Applied Science and Engineering Progress
Applied Science and Engineering Progress (ISSN: 2672-9156, Online-ISSN: 2673-0421) is an international, double-blind peer-reviewed by at least two independent reviewers, open access scientific journal, free of charge, published by King Mongkut’s University of Technology North Bangkok (KMUTNB) since 2008. Applied Science and Engineering Progress published original research articles, reviews, and editorial corner in areas of applied science and engineering. The journal also publishes high quality and peer-reviewed papers presented at conference hosted/co-hosted by KMUTNB to expand the research connection between scientists and engineers. Applied Science and Engineering Progress also aims to introduce research progress of applied science and achievements of engineering development to the world community by demonstrating the significance of research investigations and demonstrations. Journal Abbreviation: Appl. Sci. Eng. Prog. Language: English Publication Fee: 200 USD (For manuscripts submitted after Oct. 1, 2025) Issues per Year: 4 Issues (Jan-March, April-June, July-September, and October-December) Journal Statistics Average days to acceptance: 60 days Average days to first decision: 4 days Acceptance rate in 2025: 10.2% SCOPUS Citations/article during 2019-2025 is 7.2 (update 30 Dec. 2025)
Process Modelling and Optimization of Palm Oil Biodiesel Production Using Aspen Plus and Response Surface Methodology
Copyright (c) 2026 Applied Science and Engineering Progress
The Effect of CaCl2 Cross-Binding Agent Concentration on Alginate-Carboxymethyl Cellulose-Oil Palm Empty Fruit Bunches Gel Granules as a Methylene Blue Adsorbent
Water pollution caused by synthetic dye waste, such as methylene blue, poses a serious environmental problem due to its resistance to natural degradation. This issue can be addressed by utilizing carboxymethyl cellulose (CMC) derived from oil palm empty fruit bunches (OPEFB), which not only helps reduce palm oil industry waste but also produces value-added materials for environmental applications. This study aimed to investigate the effect of varying concentrations of calcium chloride (CaCl₂) as a crosslinking agent on the synthesis of alginate–CMC gel beads derived from OPEFB, used as adsorbents for methylene blue wastewater. The study was conducted in three stages: synthesis, characterization, and application, using CaCl₂ concentrations of 3%, 4%, 5%, 6%, and 7%. The observed parameters included swelling ratio, functional group interactions (FTIR), surface morphology (SEM), and adsorption capacity for methylene blue. The results indicated that the optimal CaCl₂ concentration was 3%, achieving the highest swelling ratio of 65.35% and a maximum adsorption capacity of 3.59 mg/g. Characterization results showed that increasing the CaCl₂ concentration led to the formation of a denser gel structure with lower swelling capacity, as supported by SEM images, which revealed more compact surfaces at a 7% concentration. FTIR spectra confirmed the formation of ionic crosslinking between the polymer carboxylate groups and Ca²⁺ ions, as indicated by characteristic band shifts at 1614 cm⁻¹. The findings emphasize that controlling the CaCl₂ concentration is crucial for producing gel beads with optimal physical properties and enhanced adsorption performance.
DES Molar Ratio and Time-Driven Delignification of Pineapple Peel: Achieving Exceptional Lignin Removal and Cellulose Enrichment
This study examined the influence of Deep Eutectic Solvent (DESs) molar ratio and reaction time on the delignification of pineapple peel as a lignocellulosic biomass. Lactic acid was employed as the hydrogen bond donor (HBD), while choline chloride, betaine hydrochloride, and glycine were used as hydrogen bond acceptors (HBAs). The DESs molar ratios investigated were 1:4, 1:6, 1:8, and 1:10. Delignification was conducted at 121°C for 1, 2, and 3 h. The lignin, hemicellulose, and cellulose contents before and after delignification were determined using the Chesson–Datta method. Structural and morphological modifications of the biomass were evaluated by FTIR, SEM, and XRD analyses. The highest lignin removal was achieved using betaine:lactic acid DES with a molar ratio of 1:6 for 1 h. Under this condition, lignin removal reached 96.87%, with hemicellulose and cellulose contents of 7% and 79%, respectively. These results indicated that betaine:lactic acid DES effectively disrupts lignin bonds in pineapple peel compared to other DESs without damaging cellulose.
Retraction notice to "Optimization of CO₂ Gas Flow Rate and Distributor Holes Number for CO₂ Capture" [Applied Science and Engineering Progress (2026) .05.001]
Influence of Novel Hydrofluoric Acid and Nitric Acid Etchants on Performance of Photochemical Machining of Ti-6Al-4V alloy for Biomedical Applications
Photochemical machining (PCM) process is widely recognized for fabrication of precision engineering parts and components. This study examines the impact of novel hybrid Hydrofluoric Acid (HF) and Nitric Acid (HNO₃) etchant compositions on the PCM performance for cutting square-shaped (5 mm × 5 mm) cavities in Ti-6Al-4V alloy for biomedical component manufacturing. A total of 25 experiments were performed to determine the effects of etching composition and time on edge deviation (ED), material removal rate (MRR), and mean roughness depth (Rz). The novel HF-HNO₃ etchant enables precise PCM machining of Ti-6Al-4V, achieving minimum ED (29 µm) and Rz (1.82 µm) and maximum MRR (0.967 mg/min). The HF-HNO₃ composition was found to significantly affect etching kinetics, thereby affecting process productivity and the integrity of the machined surface. The findings provide deep insight into the etching behaviour of Ti-6Al-4V and establish process directions for applying PCM in the manufacturing of biomedical components.
Improvement of Sheet Metal Properties by Inducing Residual Stresses into Sheet Metal Components by Embossing and Reforming
In sheet metal forming, combination of embossing and reforming allows the mechanical properties of sheet metal materials to be specifically improved. Here, local property modification is achieved by the residual stresses induced as a result of the one-sided embossing process followed by a reforming step. The residual stresses induced in this specific way can lead to a significantly increase in the fatigue strength of processed sheet metal components. However, in order to ensure this kind of component optimization in continuous operation, the induced stresses have to be homogeneous. In this respect, the main objective of the study reported about in this paper was to identify a forming strategy, consisting of the process steps embossing and reforming, that generates preferably homogeneous residual stress distributions into sheet metal blanks. For this, numerical and experimental investigations were carried out with samples of the stainless steel (X6Cr17) having a thickness of 1.5 mm. It was found that embossing and reforming, integrated into a conventional forming process, is a novel approach to specifically induce very localized homogeneous compressive residual stresses in sheet metal materials. This eliminates the need for costly post-processing by means of surface treatment.
Natural Fiber-based Green Composites: Processing, Properties and Biomedical Applications
Since the advent of modern technological civilization, tremendous pollution has been emerged in our environment by disposing of waste material in the environment unconsciously. Some waste materials are biodegradable and some of them are non-biodegradable. Biodegradable waste, originated from plants or animals, can be decomposed by the natural organism (bacteria, fungi, etc.) and can be excluded from pollution. This degradation process may be rapid or slow but the environmental risks are low. On the other hand, non-biodegradable waste, obtained from inorganic components cannot be decomposed by the natural organism and act as a source of pollution. These wastes are being generated by humans, and every year billions tons of wastes are being dumped into the environment which puts our environment in danger. As a result, environmental consciousness has increased worldwide. This growing ecological and environmental awareness leads the world to develop eco-friendly materials. As the population grows day by day, it is not possible to reduce waste. So, it is wise to focus on developing new materials that would produce biodegradable waste. Recently, the attraction on the biocomposite (known as green composites) materials has significantly increased because it is generated from natural fiber which is biodegradable and it has the potential of being a substitute for conventional non-biodegradable products. Biocomposites are used in various industrial sectors, including the bio-medical industry. In this paper, the overall idea of natural fibers, extraction and surface modification methods of natural fiber, natural fiber-based biocomposites, fabrication and properties analysis of biocomposite, and recent applications of biocomposites in the medical sector have been reviewed. The primary incentive for developing and using biocomposite is to build a new generation of eco-friendly materials by replacing synthetic ones.
A Decision Support System for Consumer Behavior of Chinese In-bound Tourists on Functional Beverage: An Empirical Study during COVID-19 with Thailand Sandbox
The COVID-19 pandemic has challenged all business owners to maintain their businesses and find ways to cope with the uncertainty. The functional beverage market has shifted its focus to consumers’ health value and wellness while its operators still lack knowledge to develop their products to serve customer needs, particularly to penetrate new customer groups, which are tourists. Therefore, the objective of this research is to investigate major influential factors of consumer behavior and create a decision support system (DSS) of consumer behavior (CB) on functional beverage. Samples are 378 Chinese tourists who visited Thailand in 2019 before the COVID-19 outbreak. The structural equation modeling (SEM) was employed to analyze the data while the sensitivity analysis was to test model robustness. The results showed that motivation, reference group, and knowledge have indirectly influenced CB (buying behavior, brand consciousness, health consciousness, and quality consciousness) through Marketing Mix (MM) while MM has a direct influence on CB. Moreover, sensitivity analysis expressed that either increasing or decreasing place and decreasing knowledge can influence CB factors. These results confirmed that consumers in the new normal market were interested in brands, quality, and health; therefore, brand consciousness/brand creation was a crucial challenge for small and medium-sized enterprises (SMEs) in the industry as they needed to improve product quality and be informative in terms of products’ health benefits. Hence, SMEs had to develop the product serving customer needs, gaining competitive advantages, and boosting up the economic cycle of the whole tourism supply chain from Thailand’s sandbox project. The value of DSS can help entrepreneurs decide to produce beverage to meet Chinese tourists’ satisfaction and to save cost for product development. It is an applicable tool for entrepreneurs, chiefly SMEs, to penetrate a new tourism market and choose a new suitable product that serves consumer needs in terms of tastes, brand awareness, and health benefits in the post-pandemic era.
Effect of Tool Rotational Speed and Traverse Speed on Friction Stir Welding of 3D-Printed Polylactic Acid Material
Joining of polymers are usually carried out using adhesives that has a deteriorating quality at elevated working conditions thus limiting its application areas. Friction stir welding (FSW) is a growing solid-state welding technology, with applications including the welding of lightweight materials. FSW was recently introduced for joining thermoplastics materials and found successful. This study attempts in employing FSW to join polylactic acid (PLA)-based 3D printed engineering components and assess the effect of FSW process parameters (tool rotational speed and traverse speed) on the weld property. The present work uses the FSW process to butt weld 5 mm thick 3D printed PLA sheets with taper cylindrical profiled tool. For the experimentation, three different combinations of feed rates and pin rotational speeds are considered. Based on joint efficiency evaluation, it is found that tool rotational speed of 1400 rpm combined with 10 mm/min transverse speed produces the weld with high joint efficiency of 40%.
Utilization of Supercritical Carbon Dioxide and Co-solvent n-hexane to Optimize Oil Extraction from Gliricidia sepium Seeds for Biodiesel Production
This study was conducted to optimize the supercritical carbon dioxide (scCO2) extraction of oil from Gliricidia sepium seeds using response surface methodology. Initial experiments were carried out using scCO2 and scCO2 with co-solvent n-hexane to determine the effect of co-solvent addition in oil yield. In order to obtain the maximum yield, experiments were conducted using Response Surface Methodology - Face Centered Central Composite Design (RSM – FCCD) under the following conditions: pressure of 20, 30, and 40 MPa, temperature of 50, 60, and 70°C, and CO2 flow rate of 2, 2.5, and 3 mL/min. A second-order polynomial with extended cubic interaction model was significantly fitted (p < 0.05), and a high coefficient determination value (R2 = 0.98) was recorded. At a constant extraction time of 60 minutes, the best extraction yield (12.12%) was obtained at 60°C, 40 MPa, and 2.5 mL/min. The pressure, temperature, and CO2 flow rate were all found to have a significant effect on the oil yield. The oil was used in biodiesel production and its methyl ester composition was analyzed using Gas Chromatography-Flame Ionization Detector (GC-FID).
Properties of Mortars Mixed with Polystyrene and Hemp Fiber Wastes
When polystyrene (PS) and hemp fiber waste were mixed into the sand aggregate, some physical-mechanical properties of mortar changed. The PS and hemp fiber were tested as partial replacements for sand in mortar with three designated percentages of 2.5, 5.0 and 10.0% by mass. The properties of mortar with PS were found to be better than that of the mortar with hemp fiber. The water absorption of mortar with PS was comparable with the reference mortar but lower than that of mortar with hemp fiber. The compressive strength of the mortar with PS was higher than that with hemp fiber whereas the tensile strength of the mortar with 2.5% PS and hemp fiber was comparable and was higher than that of the reference mortar. The thermal conductivity of a wall plastered by mortar containing PS decreased as the PS content was increased, whereas the thermal conductivity of a wall plastered by mortar containing hemp fiber increased as the hemp fiber content was increased. Thick crack was detected in the reference wall while hair line crack occurred from the wall plastered with PS and hemp fiber mortars. The results indicated that 10.0% PS could be used as a partial replacement for sand in mortar with an improvement in some of the properties of the mortar.
Effects of Aging and Infill Pattern on Mechanical Properties of Hemp Reinforced PLA Composite Produced by Fused Filament Fabrication (FFF)
Additions of reinforcing natural fibers to polymer matrices provides an increase in mechanical properties. In addition, bio composite materials contribute to the sustainable ecosystem with their ease of recyclability. The effect of accelerated aging on the mechanical properties of PLA matrix biocomposite specimens has been observed in previous research. However, the effect of accelerated aging on the mechanical properties and the resulting mass loss of the material produced with fused filament fabrication (FFF) has been discussed for the first time in this study. Aging was applied to the biocomposite consisted of 10% hemp and PLA matrix produced at a constant rate, parallel to the tensile direction and cross (+/– 45°) angle, and the tensile stress and mass loss were examined. The aging effect has been observed even from the first week. Specimens with parallel printing to tensile direction showed a lower tensile performance than cross printing one. Since the structure in the laminates is quite durable, the adhesion performance in the laminate or through thickness direction has been low. Natural fibers are found so highly hygroscopic that chemical treatments will improve the interface and improve the mechanical properties.
The Influence of Fiber Processing and Alkaline Treatment on the Properties of Natural Fiber-reinforced Composites: A Review
Throughout generations, research on natural fiber-reinforced composites (NFRCs) has been growing and yielding promising results. The notion of blending natural fibers with polymers comes from the composite’s suitable properties, not limited to low density, availability at a low price, biodegradability, and environmental friendliness. The quest for high-performing and marketable NFRCs is driving innovation in the synthesis of such materials. A suitable combination of parameters that optimizes the mechanical and functional properties of the composites without increasing the cost of production is desired. The main objective of this review is to evaluate some of the parameters that influence the behavior and properties of NFRCs. The influence of alkaline modification and natural fiber processing parameters, such as particle size, modification concentration, soaking duration, processing temperature, fiber-to-polymer ratio, and adoption of additives, on composites are discussed. This review summarizes some of the work and provides some directions in the search of an all-around performing economic NFRC.
Mechanical, Absorption and Swelling Properties of Vinyl Ester Based Natural Fibre Hybrid Composites
Natural fibres such as Banana (B), Jute (J) and Kenaf (K) were hybridized in different stacking sequences in vinyl ester. The composites with hybridized fibres were tested to evaluate their tensile, flexural and impact properties. Further, they were also tested for their water absorption and thickness swelling behavior. The hybridization of the fibre mats had an encouraging outcome on the mechanical behavior. The JKBKBJ hybrid composite possessed the maximum tensile strength (34.12 MPa) while maximum stiffness of 1.667 GPa was observed for the KBJJBK hybrid composites. The observations from the flexural testing indicated that the hybrid composites resisted the flexural load for higher displacement. All the hybrid configurations presented better impact strength over the composites reinforced with kenaf and jute fibres. Among the hybrid composites investigated, the KJBBJK hybrid composite displayed highest impact strength (12.32 kJ/m2). The improved strength, stiffness and lower moisture absorption properties make the composites with hybridized fibres a potential candidate for the light weight structural applications.
Cationic Nanocellulose as Promising Candidate for Filtration Material of COVID-19: A Perspective
The threat of the novel coronavirus (COVID-19) pandemic is worrying as millions of people suffered from this outbreak. The COVID-19 can be airborne spreaded by attaching to human nasal or saliva secretion of an infected person or suspended fine particulates in the air. Therefore, in order to minimize the risks associated with this pandemic, an efficient, robust and affordable air‐borne virus removal filters are highly demanded for prevention of spreading viruses in hospitals, transportation hubs, schools, and/or other venues with high human turn‐over. Respirators such as N95, N99 and N100 as well as surgical masks have been widely used. To date, there is no filter standards or special filter technologies tailored for effectively adsorbing the airborne viruses. Studies had shown the electrostatic fibers were capable to entrap the negatively charged viruses including COVID-19. Researchers believed that the positive surface charge of filtration material is an important key to efficiently adsorb the negatively charged viruses. Nanocellulose has emerged as a new class of biobased material with promising potential application in the filtration of viruses. Nanocellulose is uniform in diameter and has excellent nanofibrillar morphology. To the best of our knowledge, further studies are necessary to determine the efficiency of cationic nanocellulose as filtration material of COVID-19.
A Review on the Philosophies for the Advancement of Polymer-based Composites: Past, Present and Future Perspective
Research has been consider as a tool for recycling existing scientific ideas to promote improved concepts for the development of new materials. All technological innovations have links with the ancient philosophies that are being adapted progressively. Given this, composite material development remains one of the most excellent methods to influence the environment to meet human needs. Various studies have shown that polymer-based composites have emerged as the leading group of composites that are fast displacing all other materials in several applications due to their inherent properties. Polymer-based composites can be entirely synthetic, completely natural, or a mixture of synthetic and natural-based. However, a recent desire for eco-friendly materials has shifted attention from complete synthetic-based materials to natural fibers, whether in a partial or a total replacement. Thus, this review provides an overview of research trends from synthetic to natural based polymer composites. The article also highlights the different intrinsic classifications of composites, their developments, areas of applications, and their projections into the future in line with considerations for environment and applications.
Thermal Stability and Tribological Behaviors of Tri-fillers Reinforced Epoxy Hybrid Composites
The present works investigates the thermal stability and wear behaviour of tri-fillers reinforced hybrid composites. The Silica (S), Coconut shell (C) and Graphite (G) fillers reinforced homogeneous and functional graded epoxy composites are prepared by vertical injection molding techniques. The effect of filler contents, design parameters and its interaction on wear and friction behavior of SCG composites has been investigated. With help of Taguchi’s techniques, L27 orthogonal array, a series of experiments are planned and conducted on pin-on-disc tribo machine with three different loading of 10, 20 and 30 N, three sliding velocities of 1, 1.5 and 2 m/s by varying the G filler content of 10, 20 and 30 wt% with constant weight fraction of S and C fillers of 10 wt%. The results shows that the increasing the Gr content was increased the wear resistance and rate. The optimization techniques used to determine the composites parameters.
Plant-Microbe Interactions - Insights and Views for Applications in Sustainable Agriculture
The term “microbiome” refers to the association of plants with various microorganisms which play an important role in the niches they occupy. These microorganisms are found in the endosphere, phyllosphere, and rhizosphere, of host plants which are involved in plant ecology and physiology. The structure and dynamics of the plant microbiome have been significant seen in the last few years. In addition, the plant microbiome enhances the host plant with gene pools, which is referred to as the second plant genome or extended genome. Interestingly, the microbiome associated with plant roots has received unique attention in recent years due to its important role in host nutrition, immunity, and development. Prospective studies of the microbiome have been coupled with the need for more sustainable production for agriculture. On the other hand, various environmental factors are associated with plant-microbiome interactions that can affect composition and diversity. This review provides insights and views of plant microbiome for sustainable agriculture. Host factors that influence the microbial community, root-associated microbial consortium, commercial application, and limitation of plant microbiome were discussed. Also, this review provides current knowledge of the plant microbiome into potential biotechnology products that can be used in agricultural systems. Regardless, microbiome innovation represents the future of sustainable agriculture.
Antifungal Activity of Silver Nanoparticles with the Potential to Control Fungal Contamination in the Male Inflorescences of Palmyra Palm
Fungal contamination of the male inflorescences of palmyra palm (Borassus flabellifer Linn.) is a serious problem during their storage prior being used as the raw material for making the local One-Tambon-One-Product, a cloth holder known as “Nguang Taan Hom” made by the Phutaan Entrepreneurship, Takua Thung District PhangNga Province, Thailand. Morphological and molecular techniques were used to identify the isolated fungi from male palmyra palm inflorescences. Three major strains: Aspergillus niger, Aspergillus fumigatus and Aspergillus sclerotiorum were studied for antifungal activities and the minimum inhibitory concentration (MIC) of silver nanoparticles (AgNPs) was found to range from 13.5–27 mg mL–1. Then, the efficiency of the AgNPs and silver nanoparticles stabilizing by Polyvinylpyrrolidone (AgNPs-PVP) on the male palmyra palm inflorescences was studied by constructing a chamber model over a period for 9 weeks. The results showed that the group inoculated with Aspergillus niger, Aspergillus fumigatus and Aspergillus sclerotiorum spores developed fungal growth after 4 weeks whereas no fungal growth was observed in the group treated with AgNPs and AgNPs-PVP at 27 μg/ mL until week 7, indicating that dipping with either AgNPs or AgNPs-PVP is able to inhibit the growth of the fungi which cause damage to raw materials and also threaten human health. Therefore, it can effectively extend the storage time of male palmyra inflorescences.
Influence of Sulfuric Acid Pretreatment and Inhibitor of Sugarcane Bagasse on the Production of Fermentable Sugar and Ethanol
Improper disposal of agricultural waste after harvesting season has posed serious health and environmental issues. Alternative methods to utilize agricultural waste to produce a value-added product, especially biofuel, have become the focus of research and industrial stakeholders. To make the process feasible, the maximum conversion should be achieved with the optimum operational condition. This research applied Response Surface Methodology (RSM) with the Box-Behnken design (BBD) to optimize sulfuric acid pretreatment of sugarcane bagasse by varying three pretreatment factors namely, acid concentration (0.5–3.5%), temperature (60–140℃), and time (20–100 min). Pretreated biomass was enzymatically hydrolyzed, and the effectiveness of pretreatment was examined according to the reducing sugar concentration. However, inhibitors namely, acetic acid, 5-hydroxymethylfurfural (5-HMF), and furfural were produced during pretreatment, which was analyzed through GC-MS analysis. The Box-Behnken design could optimize and correlate the effect of pretreatment parameters on the hydrolysis of sugarcane bagasse. The optimum pretreatment condition was predicted at an acid concentration of 3.50%, the temperature of 136.08℃, and the time of 75.36 min to obtain the maximum sugar production. Sugarcane bagasse pretreatment at optimum condition could produce a reducing sugar of 180.15 mg/g-sugarcane bagasse, which is 3.06 folds higher than untreated sugarcane bagasse. However, ethanol yield from pretreated biomass was less than unpretreated biomass because of the inhibitor formation. This study provides a new insight into utilizing agricultural waste in a more efficient and eco-friendly manner.
Influence of Incident Energy on Sisal/Epoxy Composite Subjected to Low Velocity Impact and Damage Characterization Using Ultrasonic C-Scan
Impact resistance is an inevitable characteristic of the composites employed in the high performance structural applications. Due to the growing interest in the use of sisal fibre as reinforcement in the polymer composites, it is required to determine the response of sisal/epoxy composites to low velocity impact at high incident energies where perforation can occur and assess the damage characteristics using a non-destructive technique. In this work, sisal/epoxy composites were subjected to drop weight impact in the velocity range of 3 m/s to 5 m/s at different energy levels between 20 J to 50 J according to the ASTM D7136. Based on the results observed, it is concluded that both the peak load and absorbed energy increased with the increasing incident energy level up to 40 J. At 50 J, perforation occurred and the maximum deformation was approximately 22 mm for the sisal/ epoxy composite. Damage characteristics and failure behaviour of the composite at different incident energies was examined from the visual images of the front and back face of the composite. The quantitative assessment of crack propagation in the sisal/epoxy composite and the damage area were determined from the ultrasonic C-scan images of the sample post impact at various energy levels.
Chemical Pretreatment of Lignocellulosic Biomass for the Production of Bioproducts: An Overview
Lignocellulosic biomass has attracted great interest from researchers. It was due to the abundance of this valuable material which can be converted into value-added materials such as nanocellulose, biocomposites, bioelectricity, biohydrogen and biosugars. Lignocellulosic biomass is consisting of the three major components which are cellulose, hemicellulose and lignin. In order to utilize lignocellulosic biomass for bioproducts manufacturing, they need to be pretreated prior to further processing. Pretreatment can be carried out either by mechanical, chemical, biological or combination of all these methods. Chemical pretreatment is the common method used to pretreat the lignocellulosic biomass in order to completely or partially remove the components. During the past few years, a large number of chemical pretreatment including lime, acid, steam explosion, sulfur dioxide explosion, ammonia fiber explosion, ionic liquid and others have been discovered to be efficient pretreatment of biomass. Several types of chemical pretreatment of fibers and their future direction and also challenges were tackled in this review. This review could be beneficial for future directions in the pretreatment of fiber for the development of several products.
Statistical Study of the Influence of Fiber Content, Fiber Length and Critical Length in the Mechanical Behavior of Polymeric Composites Reinforced with Carica Papaya Fibers (CPFs)
Vegetable fibers are excellent substitutes for manmade fibers because they are resistant and sustentables. This article studied the potencial application of Carica Papaya Fibers (CPF) in polymerics composites of natural resin. A simple model of micromechanical analysis was used for prediction of breaking stress, strain and Young’s modulus in composites with short fibers of Carica Papaya and matrix of polyurethane resin obtained from Ricinus Communis vegetable. The fiber contents were varied between 10–35% and fiber lengths were varied between 3–6%. The result analysis was performed using analysis of variance (ANOVA) to assess the influence of variables on the mechanical properties of each composite produced. The results showed that that increased in fiber length promoted increase in stress values, while the increase in fiber content favored the increased in the stiffness of the composite.
Performance Enhancement of Recycled Aggregate Concrete – An Experimental Study
Extensive studies have been performed on the mechanical and durability properties of the concrete prepared with recycled coarse aggregates (RCA), however, only modest consideration has been given to the studies on the behaviour of RAC prepared by alternative mixing approach techniques. This study presents the mechanical properties of the recycled aggregate concrete (RAC) with different percentages of RCA prepared by normal mixing approach (NMA), two-stage mixing approach (TSMA) and sand enveloped mixing approach (SEMA) techniques. The manufactured concrete mixtures were tested for compression, tension, flexure and elastic modulus at 7, 28 and 90 days. The results indicate that the mechanical properties of the RAC (with 100% of RCA) prepared through TSMA and SEMA were improved by 9.36 and 12.14% at 28 days. Perhaps, prolonged curing to TSMA and SEMA mixtures improved the mechanical properties of the RAC that is nearly equal to normal aggregate concrete (NAC) prepared by NMA.
Desirability of Tribo-Performance of Natural Based Thermoset and Thermoplastic Composites: A Concise Review
Tribology, which may be defined as an interdisciplinary subject, deals with relative motion between two or more bodies, i.e., surfaces that are interacting relatively. Thus, tribology is a science covering three vital classes, namely, wear, friction and lubrication. The focus of this article is to bring out the elements that are influencing the wear-resisting behavior of thermosetting and thermoplastic composites with natural-based constituents. Based on the literature resources, the treatments on the natural fibers acting as reinforcement, and the addition of fillers in resin acting as matrix could improve the wear-resisting behavior of the composites. Additionally, other conditions such as sliding speed, sliding velocity, sliding distance and operating temperature could also influence the friction coefficient and specific wear rate of the natural-based composites.
Design and Application of a Modified EWMA Control Chart for Monitoring Process Mean
The modified exponentially weighted moving average (modified EWMA) control chart is an improvement on the performance of the standard EWMA control chart for detecting small and abrupt shifts in the process mean. In this study, the effect of varying the constant and exponential smoothing parameters for detecting shifts in the mean of an autoregressive process with exogenous variables (ARX(p,r)) with a trend and exponentially distributed white noise on the standard and modified EWMA control chart was investigated. The performances of the two control charts were compared via their average run lengths (ARLs) computed by using explicit formulas and the numerical integrated equation (NIE) technique. A comparative study of the two ARL methods on the modified and traditional EWMA control charts shows that the modified schemes had better detection ability at all levels of shift size. Finally, two examples using real datasets on gold and silver prices are given to illustrate the applicability of the proposed procedure. Our findings advocate that the modified EWMA chart is excellent for monitoring ARX(p,r) processes with exponentially distributed white noise
Trends and Developments in Natural Fiber Composites
Cleaner Environment Approach by the Utilization of Low Calcium Wood Ash in Geopolymer Concrete
The waste disposal issues were the most severe problems that could cause global warming, which depletes the environment. The research hypothesis was to find the suitability and sustainability of utilizing the waste by-products in the invention of green geopolymer concrete to eliminate the tremendous effects caused by the wastes. Due to the increased demand for fly ash in recent years, the requirement of high alkaline activators, and elevated temperature for curing, there was a research gap to find an alternative binder. The novelty of this research was to utilize the waste wood ash, which is available plenty in nearby hotels and has an inbuilt composition of high potassium that can act as a self alkaline activator. Waste wood ash procured from the local hotels was replaced with fly ash by 0 to 100% at 10% intervals. The setting and mechanical characteristics were found on the prolonged ages to understand the influence of waste wood ash. Microstructural characterization was found using Scanning Electron Microscope and X-Ray Diffraction Analysis to define the impact of waste wood ash in the microstructure. The research findings showed that replacing 30% waste wood ash with fly ash attained better performance in setting properties and all mechanical parameters. The obtained optimum mix could provide the best alternative for fly ash in geopolymer to eliminate the economic thrust by the requirement of alkaline activators and deploy the environmental impact caused by the waste wood ash.
Understanding and Efficiently Manipulating Environmental Stress Caused by Metal Ions to Improve Ethanol Fermentation
The inconsistent quality of molasses directly influences ethanol production, particularly due to contamination by metal ions that causes severe problems and reduces production efficiency. This research focused on calcium (Ca2+), potassium (K+), and magnesium (Mg2+) ions that are common in molasses. The key objective was to understand clearly the effect of ions on ethanol fermentation and Saccharomyces cerevisiae performance. Individual ions and ion mixtures were studied in sucrose solution and in molasses. The results showed that severe stress could be ordered as Ca2+>K+>Mg2+ and the adverse effect was greater when the ion concentration increased. Ca2+ was a strong inhibitor while trace amounts of Mg2+ produced a positive effect. To achieve the greatest efficiency in ethanol production using molasses in the substrate preparation, Ca2+ should not exceed 0.18% (w/w) prior to fermentation and the final sugar concentration should be 20–25% (w/v), as adjusting the addition of sucrose will result in a suitable yeast medium. Pretreatment and dilution were the best practices for ion removal, with Ca2+ being clearly decreased. Furthermore, determination of the composition and ion concentration in molasses are essential initial steps that must be routinely applied to ensure that the knowledge gained and the efficient techniques investigated can both be used to improve ethanol production.
Dynamic Mechanical Performance of Natural Fiber Reinforced Composites: A Brief Review
Natural fiber reinforced polymer composite is a much focused area of study owing to its environmentally friendly nature and good mechanical properties. These composites offer comparable mechanical properties to that of steel and other composite materials. Dynamic mechanical analysis is a widely used technique to investigate the mechanical performance of fiber reinforced composites at a wide range of temperatures. Using this technique, the thermal transitions and damping properties of fiber reinforced composites can be studied. These natural fiber composites are widely employed in structural applications in many industries. Here, in this short review we have presented the recent works on the dynamic properties of natural fiber reinforced composite materials with an essence of the influencing factors
High Priority Arbitration for Less Burst Data Transactions for Improved Average Waiting Time of Multi-Processor Cores
The multi-processor cores in SoC which have high burst data transactions can play a critical role while accessing the shared resources such as the off-chip memory. These processor cores can starve other processor cores that have less burst data transactions while accessing the same shared resources. The starving issue of other processor cores leads to degrade the entire system performance of the SoC. However, the arbiter architecture in the SoC design plays the best solution to manage different processor core requests and granting one of them to access the shared resources according to different scheduling algorithms. In this paper, we have designed AXI interconnect, which includes arbiter architecture to connect four processor cores represented by the AXI masters and the off-chip memory represented by the salve. Each processor core (AXI Master) uses the AXI4 interface protocol to improve the system performance and the arbiter based on the static fixed-priority algorithm to improve the average waiting time for all the processor cores. The SoC design architecture is modeled in System Verilog HDL; simulation and synthesis are done by using the Vivado tool and FPGA ZYNQ-7 ZC702 Evaluation Board (xc7z020clg484-1).
Fabrication and Experimental Testing of Hybrid Composite Material Having Biodegradable Bagasse Fiber in a Modified Epoxy Resin: Evaluation of Mechanical and Morphological Behavior
Natural fibers such as bagasse, jute, sisal and coir are biodegradable as well as non-toxic in nature, so the use of natural fiber is safe. Bagasse contains about 50% cellulose, 25% hemicellulose, and 25% lignin. The present work has been undertaken to develop a composite using bagasse fiber as reinforcement and to study its mechanical properties, morphology, water absorption capacity and performance. The composites were prepared with different weight percentage of bagasse fiber by hand lay-up method. In the present research work, it can be concluded that with increase in wt% of bagasse fiber in matrix material the rate of water absorption increases. Ultimate tensile strength, ultimate compressive and flexural strength of the composite are less than the pure epoxy while Young’s modulus is higher for composite. Ultimate tensile, ultimate compressive strength and flexural strength of composite is decreasing at all cross head speed with increase in wt% of bagasse fiber while flexural strain is increasing. Scanning Electron Microscopy (SEM) showed that for 5 wt% of bagasse fiber the binding between epoxy and bagasse fiber is better than the 10 and 15 wt% of bagasse fiber configuration. This was because of the increase in wt% of bagasse fiber, which results in cavities and improper binding in the composite domain. Thus, as we increase the wt% of bagasse fiber, it causes the decrease in mechanical properties of composite.
Spanish Broom Fibres Properties and Extraction for Application in Composites: A Review
The development of a number of natural fibre products for textiles was attempted during the period of Italian autarchy (1935–1943) under the direct support of the Fascist regime. Among these fibre products, Spanish broom fibre is derived from the stem of Spartium junceum, a spontaneous plant in large parts of Italy, especially in the Southern region of Calabria. The extraction of the fibre proved cumbersome though, especially for the hardness of the stem. Therefore, different retting processes were developed, mechanical, chemical and also bacterial and, in the latter case through the use of Clostridium felsineum, it was proved to be effective to a point allowing the production of textiles. The historical events linked to the fall of the dictatorship led to some oblivion and also to the possible loss of archive materials. The objective of this review is to elicit ideas and developments concerning an effective extraction and degumming of Spanish broom fibres and evaluate the more recent applications to the field of biocomposites.
Effects of Enzyme Types and Extraction Conditions on Protein Recovery and Antioxidant Properties of Hydrolysed Proteins Derived from Defatted Lemna minor
Lemna minor (L. minor), the common duckweed, contains a high protein substance and is considered as a good source of potential bioactive peptides. The objective of this study is to investigate the effect of enzymatic hydrolysis times (60–180 min) and enzyme concentrations (0.5–3.5%v/w) with Alcalase and Flavourzyme on the recovery, hydrolysis degree (DH), and antioxidant properties of peptides derived from defatted L. minor. The protein recovery, hydrolysis degree (DH), and antioxidant activities obtained by enzymatic were compared with the alkaline treatment method. The results showed that the protein recovery, DH values, and antioxidant activities were enhanced by increasing the enzyme concentration and hydrolysis time. Specifically, the recovery of protein and DH values reached the highest level after the enzymatic hydrolysis by Flavourzyme or Alcalase at 1.5 v/w enzyme for 120 min. At the same enzymatic hydrolysis condition, the samples hydrolyzed by Flavourzyme had a higher inhibitory effect on the ABTS•+ and DPPH•+ radical scavenging than those hydrolyzed by Alcalase and the alkaline treatment. Further study also showed that the DH values, amino acid contents, and antioxidant activities of the protein extracts were positively correlated. Thus, the extractions with Flavourzyme and Alcalse were a good method to produce a significant amount of amino acids and smaller peptides.
The Effectiveness of Mirror Therapy to Upper Extremity Rehabilitation in Acute Stroke Patients
Rehabilitation is a crucial part of stroke recovery to help them regain use of their limb. The aim of this article was to compare the effectiveness of long-term training of mirror therapy with conventional rehabilitation therapy on neurological and recovery of upper limb in acute stroke patients. In this randomized and assessor-blinded control study, 20 acute stroke patients were analyzed in this study and allocated to a case (n = 10, 50.6 ± 17.90 years) and control group (n = 10, 55.9 ± 11.25 years). All the participants performed daily home exercise during 12 weeks. The patients in the control group were treated with conventional therapy (CT) and a group of cases were treated with mirror therapy (MT) alone program. The outcome measurements were assessed by a therapist blinded assessor using Fugl-Meyer Assessment (FMA) upper extremity score, Brunnstrom recovery stages (BRS), Modified Ashworth Scale (MAS) and Muscle Strength to evaluate upper limb motor function and motor recovery. Data were analyzed using Wilcoxon and Mann-Whitney U tests to compare within-groups and between-group differences. The results revealed that, after 12 weeks of treatment, patients of both groups presented statistically significant improvements in all the variables measured (p < 0.05). Compared with the control group, the patients of the MT group had greater improvement in the proximal movement portion of the FMA upper extremity mean score change (15.8 ± 3.2 versus 10.0 ± 2.7, p = 0.002) while there were no differences in other variables (p > 0.05). There were also no adverse events. It suggests that 12 weeks training of mirror therapy alone was likely to improve the motor recovery of the upper limb and activity of daily living in acute stroke patients than conventional therapy, if treated early.
Mirror Therapy Rehabilitation for Lower Limb of Acute Stroke Patients
This paper aims to study the effectiveness of mirror therapy (MT) having treated to acute stroke patients. The subjects of 20 acute stroke patients, who possessed the ability to respond to verbal instructions were randomly blinded and allocated to a control group (n = 10, 59.2 ± 2.28 years) and a mirror group (n = 10, 53.8 ± 6.14 years). Both groups were treated by intervention of traditional rehabilitation therapy comparing with mirror therapy. Intervention of mirror therapy was taken 60 minutes per day, 5 days per week for 12 weeks. Measures of intervention effectiveness were taken before treatment and after treatment by therapist using Brunnstrom stages, Fugl-Meyer Assessment (FMA) lower extremity score and Brunnel Balance Assessment (BBA) balance. Data were analyzed using independent sample t-test. The results revealed that, after 12 weeks of treatment, subjects of both groups gained statistically significant improvements in all variables measure (p < 0.05). Having compared with the control group, the participants of the MT group had greater improvement on the FMA score (31.0 ± 1.20 versus 28.7 ± 0.58). MT is inexpensive and easily applicable in conjunction with traditional physiotherapy for home care program. Consequently, MT proves to be an effective approach for rehabilitation of patients with post-acute stroke.
Different Chilling-Induced Symptoms and the Underlying Oxidative Stress and Antioxidative Defense in the Exocarp and Mesocarp of Immature Sponge Gourd (Luffa cylindrica) Fruit
Immature sponge gourd fruit is consumed as a vegetable with a limited shelf life. Although cold storage is a simple and powerful tool for maintaining postharvest fruit quality, storage at a low temperature may not be appropriate for vegetables as some chilling injury (CI) of the immature sponge gourd fruit may occur. Therefore, this research aimed to elucidate the relationship between CI, oxidative stress, and the antioxidative defense mechanisms in the exocarp and mesocarp of immature sponge gourd fruit. After storage at 5°C for 6 days, visual CI symptoms, including browning and surface pitting, were found in the peel (exocarp) but not in the mesocarp. There were, however, more dead cells (stained by Evans blue) in the mesocarp of the fruit stored at 5°C. There was a more considerable increase in the electrolyte leakage rate in both fruit tissues held at 5°C than 25°C. The CI was correlated with malondialdehyde (MDA) levels in the tissues. The MDA of fruit exocarp at 5°C was 1.6 fold higher than that at 25°C on day 6, while the lipoxygenase (LOX) activity in mesocarp was 50% higher in fruit stored at a lower temperature. The action of ascorbate peroxidase (APX) was high in the exocarp of the fruit stored at 5°C, but there appeared to be a continuous depletion of the co-substrate or ascorbic acid. In conclusion, the CI in the exocarp was mainly associated with a high level of reactive oxygen species (ROS). In contrast, the CI in the mesocarp appeared to be primarily associated with increased lipid peroxidation by the elevated LOX activity under cold stress compared to storage at 25°C.
Optimization of Hydraulic Retention Time and Organic Loading Rate in Anaerobic Digestion of Squeezed Pineapple Liquid Wastes for Biogas Production
Pineapple wastes are produced in huge amount during the industrial canning process of pineapple; in Thailand over 400,000 tons per annum of canned pineapple exported leaving behind the waste. Besides the pulps and peels as solid wastes, the squeezed pineapple liquid wastes (SPLW) extracted from solid wastes can also be used for anaerobic digestion. In the present study, the anaerobic digestion of liquid squeezed from industrial pineapple peels was carried out using a lab-scale hybrid reactor. The reactor was operated for over 170 days with the hydraulic retention time (HRT) of 20 days decreasing down to 5 days and simultaneous control of organic loading rate (OLR). Under controlled conditions in the hybrid reactor, pH was maintained at 6.5–7.6 by adding alkaline for anaerobic microbial activity. Results showed that the chemical oxygen demand (COD) removal efficiency was at ≥ 90% for all conditions. The biogas production (mL/day) increased thoroughly from longer HRT to shorter HRT, as same as methane production with the maximum values (HRT 5 days, OLR 5 g/COD/ day with recirculation) of 55,130 and 30,322 mL/day, respectively. Moreover, the highest yields of biogas and methane were also investigated under similar conditions with the values of 0.504 and 0.277 L/gCOD, respectively. Interestingly, this optimization of both HRT and OLR of lab-scale anaerobic digestion process could be further practically applied to pilot or industrial scale in canned pineapple factories for biogas production.
Production of Food Flavouring Agents by Enzymatic Reaction and Microbial Fermentation
Rising trends in the consumptions of food flavour compounds lead to motivation in the production of food flavours. The conventional techniques of flavour production are insufficient to produce flavour compounds according to the ascending demands of the market in terms of quantities and varieties. The current flavour production methods utilize chemical synthesis, which can produce a greater numbers of flavours with less time. However, the demand for natural products in consumables have created a necessity for new methodologies to produce flavour compounds with the label of “natural” origin. Emerging techniques in biotechnologies have enabled industries to produce compounds that can be considered natural. This review provides insights into the classification of flavour compounds and their production using microorganisms and enzymes in an ecofriendlier manner. The compounds produced by these techniques can be labelled as “natural” and can increase the market size of food flavours.
Investigation of the Sound Absorption and Transmission Loss Performances of Green Homogenous and Hybrid Luffa and Jute Fiber Samples
In order to promote the use of natural fibers in noise and vibration applications, the properties of these structures should be fully identified. The sound absorption coefficients (SACs) and transmission losses (TLs) of green luffa fiber samples are thoroughly investigated and their acoustic performances are compared with the acoustic performances of green homogenous jute and hybrid jute/luffa fiber samples in this study. For this purpose, green homogenous luffa and jute fiber samples and their green hybrid fiber samples with different thicknesses (10, 20, 30, and 40 mm) are produced and their SACs and TLs are determined using the impedance tube method. First, the methods for the experimental identification of acoustic properties are presented and the variations in the measured acoustic properties are identified. After that, the effects of sample thickness on the acoustic performances of homogenous luffa as well as jute samples and their hybrid fiber samples as a function of frequency are explored. The thickness-dependent tendencies of the SACs and TLs of homogenous and hybrid luffa and jute fiber samples for low, medium and high frequency ranges are determined. Then, the acoustic performances of the homogenous and hybrid luffa and jute samples are compared and evaluated. The results and analyses for the acoustic properties of homogeneous luffa and jute fiber samples and their hybrid fiber samples for a variety of thicknesses and different frequencies presented here can be used to design homogenous as well as hybrid luffa and jute fiber structures in practical applications.
Bi-Template Assisted Sol-Gel Synthesis of Photocatalytically-Active Mesoporous Anatase TiO2 Nanoparticles
Sol-gel mesoporous titanium dioxide powders have been synthesized from chitosan and/or hexadecyltrimethylammonium bromide (HDTMA) and characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and N2 adsorption-desorption measurements. The photocatalytic performance of the synthesized meso-TiO2 powders was optimized based on the central composite design (CCD) of methyl orange (MO) degradation under UV light irradiation. The maximum MO degradation was 62.3% over a period of 60 min. Oxides produced using the binary chitosan and HDTMA template (C,H-TiO2) exhibited the relatively higher surface area (99.5 m2/g), smaller crystal size (12.78 nm), narrower band-gap energy (2.92 eV) and higher photocatalytic rate constant (0.0112 min–1) than as those from chitosan (C/TiO2) or HDTMA (H/TiO2) as the template.
Treated Clay Mineral as Adsorbent for the Removal of Heavy Metals from Aqueous Solution
The decontamination of heavy metals present in aquatic bodies is a significant challenge that requires urgent attention. Analytical methods such as BET, XRF, SEM-EDX, and XRD was employed to characterize the raw clay (NT) and acid treated clay (AT). The adsorption of Cr (VI) and Fe (III) onto AT was performed using the batch method. The effects of time, adsorbent dose, temperature, and pH show that the optimal conditions are 50 min, 0.3 g, 35°C, and pH 6. The surface area of AT was 389.37 m2/g, and the adsorption equilibrium time of AT was 50 min. Langmuir isotherms had the best fit. Adsorption capacity is 18.15 and 39.80 mg/g for Cr (VI) and Fe (III) ions, respectively. An increase in area considerably improved the adsorption capacity of AT in the surface specific area. The interaction of Cr (VI) and Fe (III) ions onto AT indicated spontaneous and endothermic reaction. The chromium (VI) kinetic constant (k2 = 1.679) was faster compared to Fe (III) rate constant (k2 = 0.0526). It agreed correctly with the pseudo-second-order equation. The sum square error (SSE) value obtained confirmed the best-fit equations. The percent adsorbed for Cr (VI) and Fe (III) is 74 and 90%. The results revealed that iron has a higher affinity towards AT than chromium. The study revealed that AT could be suitable and effective in the adsorption of chromium and iron in the wastewater medium.
Treatment of Marigold Flower Processing Wastewater Using a Sequential Biological- Electrochemical Process
Agriculture is the mainstay of the Indian economy. The agro-based industries produce high volumes of highstrength wastewaters that need to be treated and reused to prevent environmental pollution and water wastage. This study evaluated the performances of a sequential biological-electrochemical process for treating an anaerobically digested effluent of a Marigold flower processing agro-industry. The uniqueness of this wastewater possess a major challenge to its treatment since not many studies have been conducted on this wastewater. The biological treatment was carried out in a Sequential Batch Reactor (SBR). The treated water was further polished in a Continuous Bipolar-mode Electrochemical Reactor (ECR) to remove the residual organics. The anaerobically digested effluent Chemical Oxygen Demand (COD), Dissolved Organic Carbon (DOC), Total Nitrogen (TN), Total Phosphorus (TP) and Total Suspended Solids (TSS) were 5750 ± 991 mg/L, 980 ± 120 mg/L, 692 ± 60 mg/L, 9.7 ± 1.1 mg/L, and 1144 ± 166 mg/L, respectively. A significant level of treatment was achieved in the SBR. The combined system was able to remove 79% of COD, 85% of DOC, 53% of TN, and almost 100% of TP, TSS, and Volatile Suspended Solids (VSS). Several organic compounds belonging to the category of natural plants compound, pesticide, fungicide, etc. were detected in the raw wastewater. Most of the compounds were almost completely removed by the treatment system. The final effluent was almost colorless and free from suspended solids. However, for reuse, the water needs to be further treated in an advanced oxidation process.
Bioethanol Production by Pichia stipitis Immobilized on Water Hyacinth and Thin-Shell Silk Cocoon
Cell immobilization technique was applied in this study in order to examine effect of immobilized Pichia stipitis TISTR5806 on bioethanol production. Water hyacinth (WH) and thin-shell silk cocoon (CC) were used as cell carriers. Characteristics of the cell carriers were examined to explain the mechanism of bioethanol production. Carrier sizes and weights were optimized to improve bioethanol production. Moreover, stabilities of immobilized cells and carriers were evaluated. Because of high porosity, high surface area and good swelling ability of WH, cell immobilized on 1 g WH with 1 cm length produced the highest ethanol concentration at 13.3 g/L. Five cycles of a repeated batch of immobilized cell (IC) system on WH showed stable performance in ethanol production (8.2–10.4 g/L) with large numbers of the immobilized cells. The interaction between the immobilized cells and the WH surface were discovered.
Mining Bug Report Repositories to Identify Significant Information for Software Bug Fixing
Most studies relating to bug reports aims to automatically identify necessary information from bug reports for software bug fixing. Unfortunately, the study of bug reports focuses only on one issue, but more complete and comprehensive software bug fixing would be facilitated by assessing multiple issues concurrently. This becomes a challenge in this study, where it aims to present a method of identifying bug reports at severe level from a bug report repository, together with assembling their related bug reports to visualize the overall picture of a software problem domain. The proposed method is called “mining bug report repositories”. Two techniques of text mining are applied as the main mechanisms in this method. First, classification is applied for identifying severe bug reports, called “bug severity classification”, while “threshold-based similarity analysis” is then applied to assemble bug reports that are related to a bug report at severe level. Our datasets are from three opensource namely SeaMonkey, Firefox, and Core:Layout downloaded from the Bugzilla. Finally, the best models from the proposed method are selected and compared with two baseline methods. For identifying severe bug reports using classification technique, the results show that our method improved accuracy, F1, and AUC scores over the baseline by 11.39, 11.63, and 19% respectively. Meanwhile, for assembling related bug reports using threshold-based similarity technique, the results show that our method improved precision, and likelihood scores over the other baseline by 15.76, and 9.14% respectively. This demonstrate that our proposed method may help increasing chance to fix bugs completely.
D-Optimal Design Optimization for the Separation of Oleic Acid from Malaysian High Free Fatty Acid Crude Palm Oil Fatty Acids Mixture Using Urea Complex Fractionation
Oleic acid (OA) rich vegetable oils is important for the daily essential dietary oils intake but restrict to particular oil such as olive oil. However OA enrichment to other vegetable oil such as palm oil is always possible. OA can be obtained from cheap resources such as high free fatty acid crude palm oil (HFFA-CPO). OA concentrate from HFFA-CPO fatty acids mixture requires efficient and low cost technique. Urea complex crystallization fractionation is a classic method for fractionating saturated and monounsaturated fatty acids from polyunsaturated fatty acids of many vegetable oils. In this work, the separation and purification of oleic acid (OA) from unsaturated fatty acids mixture fraction (USFA) of HFFA-CPO fatty acids mixture by urea complex fractionation (UCF) was studied. The crystallization reaction conditions of urea inclusion for the non-urea complex fraction (NUCF) were optimized using the response surface methodology (RSM) and the optimal model was developed. The results showed high content of OA (88%) in urea complex fraction (UCF) with 86% yield at optimal conditions of urea-to-USFAs ratio of 4.62 : 1 (w/w), crystallization temperature at –10°C and crystallization time of 24 h. The results have demonstrated that urea complex crystallization fractionation method is a very effective with low cost, stable, obtainable, and comparatively ease to recover of OA from polyunsaturated fatty acids (PUFA) of an oil fatty acids mixture. Pure OA is plausible to be used back for the OA enrichment modification into palm oil for new dietary oil.
A Comprehensive Review on the Drying Kinetics of Common Tubers
Sun-drying has been conventionally used in the production of tuber-derived commodities such as cassava, potato, sweet potato, and yam. Recent developments in the drying process involves the use of different drying equipment to improve quality and profitability. The importance of drying parameters in the operation of drying equipment necessitates drying kinetic studies on common tubers. This article aims to review the drying kinetics studies conducted on common tubers. Particular interest is on the effect of the drying process parameters like temperature and velocity of heating air medium, the physico-chemical pretreatment method, and sample preparation on the drying rate and time. The different best fit drying kinetic models for specific tubers have also been extensively studied. The role of drying process parameters and best fit model equations on the design of the drying equipment has been emphasized.
Explicit Formulas of ARL on Double Moving Average Control Chart for Monitoring Process Mean of ZIPINAR(1) Model with an Excessive Number of Zeros
Usually, the performance of control charts are widely measured by average run length (ARL). In this paper, the derivative explicit formulas of the ARL for double moving average (DMA) control chart are proposed for monitoring the process mean of zero-inflated Poisson integer-valued autoregressive first-order (ZIPINAR(1)) model. This model is fit when there are an excessive number of zeros in the count data. The performance of the DMA control chart is compared with the results of moving average and Shewhart control charts by considering from out of control average run length (ARL1). The numerical results found that the DMA control chart performed better than other control charts in order to detect mean shift in the process. In addition, the real-world application of the DMA control chart for ZIPINAR(1) process is addressed.
Numerical Modeling for Corrosion Rate between Heat-affected Zone and Unaffected Base Metal of Galvanized Steel Welded by Brazing
Brazing of galvanized steel causes decaying of the zinc coating and decreasing of corrosion resistance on heat-affected zone (HAZ) and weldment. The corrosion rates among the HAZ, unaffected base metal (UBM), and weldment of galvanized steel welded by brazing were numerically modeled by COMSOL Multiphysics. The numerically modeled current density values from various zones, such as the couples between the HAZ and the UBM, between the weldment and the HAZ, and between the UBM and steel were used to calculate the corrosion rates. In this work, two different methods based on Faraday’s Law, the mixed potential theory and the Numerical modeling, were compared for calculations of the corrosion rates of each region. Using the mixed potential theory, the calculated corrosion rates of regions I, II, III, IV, V and VI were 0.853, 0.284, 2.105,1.754, 2.028 and 0.554 mm/y, respectively. Where as based on the Numerical modeling, these rates of all regions were 0.918, 0.275, 2.198, 1.904, 2.151, and 0.566 mm/y, in orderly. These comparisons suggested that the corrosion rates obtained from the two methods were similar. However, the results showed that the Numerical modeling method could predict the corrosion rate with less error.
Enhancement of PHB Production Process in a Fed-Batch Bioreactor Using Input-Output Linearization Technique with Optimal Setpoints
Polyhydroxy butyrate (PHB) is a polyester that has been widely applied to formulate bioplastics. A challenge for the PHB production is the enhancement of PHB accumulation in bacterial cells, which can be conducted through the nutrient feeding strategy. A control system based on an input/output (I/O) linearization technique for the PHB production in a fed-batch bioreactor is proposed in this work. The concept of feast/famine phase is employed to provide the optimal desired targets for each time instant through optimization problems. The developed controller is applied to regulate the controlled output to follow the desired setpoints by manipulating the feed flow rate of nutrients. Simulation results show that the proposed control system attempts to follow the optimal desired targets (discrete-time approach) during the process operation. The accumulation of PHB in bacterial cells is around 25% higher than that of the process with a modified PI controller. Control performance tests indicate that the proposed control strategy successfully regulates the process according to the desired targets and handles the process disturbance effectively.
Corrosion Behaviour of AISI409 Stainless Steel with Al Slurry Coating in Molten Salt
A concentrated solar power plant produces electricity by collecting thermal energy from sunlight. Then the thermal energy is stored in the heat transfer fluid (HTF). The most widely used and studied HTF is solar salt (60wt%NaNO3–40wt%KNO3) that achieves the most requirements of HTF. However, at high temperatures, the corrosion is still violent for most materials, thus the material selection is important. This research aims to investigate the feasibility for application of AISI 409 ferritic stainless steel as containers of the molten salt. AISI 409 is suitable for high temperature usage, and more economical than other grades which have higher chromium. To investigate the corrosion resistance in molten salt, AISI 409 samples were coated by dipping in Al slurry. Then they were heated up to 400°C to remove binders. The coatings with Fe-Al intermetallic and alumina layers were formed after binder removal and subsequently annealing at 700°C for 3 h in the air atmosphere. This research reported the corrosion behaviour of Al coated and uncoated samples which had been treated by immersion in molten salt at 500°C for 100 h with analysis results. The results demonstrated that weight and thickness of uncoated samples were increased due to formation of the oxide layers such as Fe2O3 and Fe3O4 on the surfaces. For the Al coated samples, the weight and thickness of the coat layers were massively decreased after being immersed in molten salt at the first 1 h due to removal of Al-O, slag or impurity in the coating. Nevertheless, the weight increased gradually until 100 h. The oxidation of the Fe-Al intermetallic layer exhibited about 35% slower oxidation than that of uncoated samples, thus the coating technique has potential to be applied against molten salt.
Application of Statistical Solvent Mixture Design in Optimizing the Solid-Liquid Extraction of Phenolic Compounds from Mango Seed Kernels
Mango seed kernel (MSK) is a waste material of the mango processing industry and is reported to significantly contain phenolic compounds with anti-oxidative properties. In this work, these compounds are isolated via solid-liquid extraction (SLE) in which solvent mixture design approach was used to evaluate the optimal quaternary solvent ratio in relation to the phenolics content of extracts from MSK. The quaternary solvent is composed of ethanol (E), methanol (M), acetone (A), and water (W). The extraction process was implemented at 40°C for 60 minutes with the ratio between solid and solvent at 1:25. Response surface methodology coupled with simplex lattice design was developed to evaluate the optimal solvent system and their interaction effects on the phenolic compounds content. The linear, two-way, and three-way interaction, except for methanol-acetonewater system, resulted in positive effects on the phenolic compounds content. The response model shows that a quaternary mixture with approximately 3:3:3:1 E:M:A:W ratio provided the highest phenolic content. A Scheffé cubic model sufficiently described the extraction process. The results of this study showed that the extraction of phenolic compounds in MSK via SLE using a mixture of solvents is possible. Higher extraction efficiencies can be achieved by optimizing the SLE process, and the optimum conditions can be applied to produce phenolic extracts with positive antioxidant activity.
Modification of Waste Leather Trimming with in Situ Generated Silver Nanoparticles by One Step Method
Waste leather trimming (WLT) was modified by in situ generation of silver nanoparticles (AgNPs) and silver oxide nanoparticles (Ag2ONPs) by one step thermal assisted method. The modified WLT was analyzed by FTIR, SEM, EDS, XRD and TGA techniques and antibacterial analysis. The generated silver based nanoparticles had a mean size of 93 nm. The FTIR spectra revealed no major changes between WLT and modified WLT. The XRD studies indicated additional peaks in the diffractogram of modified WLT which belonged to AgNPs and Ag2ONPs. The unmodified WLT had four inflection temperatures at 89, 303, 454, and 785°C while these values for the modified WLT were 84, 211, 305, and 328°C indicating a slight lowering of thermal stability due to the catalytic activity of the generated silver based nanoparticles. Further, the modified WLT formed the inhibition zones against E.coli, P.aeruinosa, S.aeureus and B.lichinomonas bacteria with diameters of 33, 36, 29, and 30 mm respectively. Hence, the modified WLT can be considered as filler for making low cost antibacterial biocomposites.
Binary Integer Programming Approach to Optimal Content Placement in Cloud-based Content Delivery Networks
Over the last decades, Content Delivery Networks (CDNs) have been developed to overcome the limitation of user perceived latency by replicating contents from origin server to its content servers around the globe close to clients. As some contents occupy most of the storage capacity and processing power in traditional private content servers, cloud computing can provide a pool of storage and processing power resources for caching contents. By adopting cloud computing to CDN, the content provider can use the cloud infrastructure by distributing the contents to cloud servers which will then deliver to near clients. In this paper, we propose a cloud-based CDN framework designed by two schemes 1) UDP/TCP-based content distribution from origin server to cloud servers and 2) SDN-based cloud server coordination. In addition, we also formulate the optimal content placement problem using binary integer programming to minimize the total cost of renting resources including storage, processing power, and network bandwidth in cloud providers for hosting contents from origin server. Then, the optimal solution obtained from binary integer programming is evaluated by greedy algorithm and simulations. The proposed framework helps content provider to offer high quality of services to clients while minimizing the cost of rented cloud resources.
Evaluation of Eutrophication State of Mae Kuang Reservoir, Chiang Mai, Thailand by Using Carlson’s Trophic State Index
Eutrophication is an event that occurred when the lakes have a high growth rate of phytoplankton and causing deterioration of water quality. In this work, we use Carlson’s Trophic State Index (CTSI) to evaluate the situation of eutrophication of Mae Kuang Reservoir for the first time. Three parameters, i.e., total phosphorus, chlorophyll-a, and water transparency were used to calculate CTSI. The results showed that the reservoir has started to be eutrophic. In June and October, the ranges of the CTSI were 49.26–59.60 and 49.07–56.04, respectively, which indicated a low eutrophic state of the reservoir. However, in this primary eutrophic condition, the water quality was not bad, and the living organisms can survive. The CTSI is a valuable and simple alternative method for monitoring and estimating lake ecosystems' eutrophic status.
Effective Data Augmentation and Training Techniques for Improving Deep Learning in Plant Leaf Disease Recognition
Plant disease is the most common problem in agriculture. Usually, the symptoms appear on leaves of the plants which allow farmers to diagnose and prevent the disease from spreading to other areas. An accurate and consistent plant disease recognition system can help prevent the spread of diseases and save maintenance costs. In this research, we present a plant leaf disease recognition system using two deep convolutional neural networks (CNNs); MobileNetV2 and NasNetMobile. These CNN architectures are designed to be suitable for smartphones due to the models being small. We have experimented on training techniques; online, offline, and mixed training techniques on two plant leaf diseases. As for data augmentation techniques, we found that the combination of rotation, shift, and zoom techniques significantly increases the performance of the CNN architectures. The experimental results show that the most accurate algorithm for plant leaf disease recognition is NASNetMobile architecture using transfer learning. Additionally, the most accurate result is obtained when combining the offline training technique with data augmentation techniques.
Natural and Synthetic Antioxidants Prevent the Degradation of Vitamin D3 Fortification in Canola Oil during Baking and In Vitro Digestion
Vitamin D insufficiency is widespread in the northern and partly equatorial hemisphere countries. Fortification of vitamin D in commonly consumed vegetable oils can prevent rickets in children, osteoporosis and bone fractures in adults. Avoiding the loss of vitamin D3 fortification in oils during cooking is beneficial for consumer’s health. The aim of this work was to investigate the stability of cholecalciferol (vitamin D3) fortification in canola oil during baking at 80 to 230°C for 10 to 40 min. The natural antioxidants (β-carotene and α-tocopherol) and the synthetic ones (butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ)) were used to prevent the degradation of vitamin D3. The kinetic degradation of vitamin D3, oxidative status of canola oil and the bioaccessibility in in vitro digestion were assessed. Vitamin D3 was relatively stable at 80 and 130°C for 10 to 40 min. High temperatures of 180 and 230°C caused the highest loss of vitamin D3 being up to 90%. Reaction rate of vitamin D3 degradation ranged from 2.01 to 6.80 × 10–2 sec–1. BHT and TBHQ had the highest antioxidant activity (> 50 %) to decrease the degradation of vitamin D3 at 230°C. The oxidative status (peroxide value, malondialdehyde content) of canola oil was improved after incorporating antioxidant agents. The vitamin D3 bioaccessibility was increased 1.5 fold after in vitro digestion. The consumption of 5 g brownie containing vitamin D3 100 μg/L and antioxidant agents 180 mg/L in 1 mL of canola oil would cover the daily intake.
Hot Forging Process Design and Initial Billet Size Optimization for Manufacturing of the Talar Body Prosthesis by Finite Element Modeling
In hot forging industry, the process design and the billet size determination are very crucial steps because those steps directly influence both the product quality and material utilization. The purpose of this paper was to propose a technique used to design the hot forging process for the manufacturing of the talar body prosthesis. The talar body prosthesis is one of the artificial bones, which its geometry is a free form shape. In this study, the Finite Element Modeling (FEM) was used as a tool to verify the proposed design before implementation in a production line. In addition, an initial billet was determined the optimum size in the FEM by varying the mass ratio factor, the diameter, and the length. It was found that the mass ratio factor is a very useful guideline since the optimum size is quite close to the provided size from the guideline. The FEM results showed that the dimensions of the initial billet significantly affect the complete metal filling in the die cavity. Moreover, the optimum size between the diameter and length can reduce the material waste in the hot forging process of the talar body prosthesis. Finally, the experimental results of the hot forging process showed that the proposed process design with the optimum size of the initial billet is achieved in order to manufacture the talar body prosthesis and the material utilization of the new proposed process is improved from the traditional process by 2.6 times.
Photocatalytic Degradation of Diazinon in g-C3N4/Fe(III)/persulfate system under Visible LED Light Irradiation
In the past years, the non-conventional treatment of pesticides in wastewater like photocatalytic degradation has been the focus of the attention of researchers to mitigate its impact on both humans and the environment. In this study, synthesized graphitic carbon nitride (g-C3N4) from urea is used in the photocatalytic degradation of diazinon as a photocatalyst with the addition of ferric nitrate (Fe3(NO3)3) and potassium persulfate (K2S2O8) to enhanced degradation. Graphitic carbon nitride was produced using direct calcination of urea at 550°C for 2 h. The physicochemical properties of the synthesized g-C3N4 were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), and X-ray Diffractometer (XRD). The photocatalytic degradation of diazinon was conducted under a g-C3N4/Fe(III)/persulfate system using different parameters such as catalyst loading (75, 100, and 125 mg), Fe3(NO3)3 (325, 350, and 375 mg L–1), and K2S2O8 (275, 300, and 325 mg L–1) resulting to an improved photocatalytic degradation efficiency. The physicochemical results showed a synthesized g-C3N4 that exhibits properties that are following the international standards. The results of photocatalytic degradation showed the highest degradation of g-C3N4 at 37.3%, under the parametric conditions of 125 mg g-C3N4, 325 mg L–1 of Fe3(NO3)3, and 300 mg L–1 of K2S2O8. The degradation efficiency was observed to increase as the catalyst load increases, while an increase in degradation efficiency can only be observed up to a certain value using ferric nitrate and persulfate. Overall, this study provided insight on the possible use of urea, as a source of g-C3N4 and the use of g-C3N4 as a photocatalyst using visible light as a more economic approach and cost-efficient way of handling wastewater.
Application of Chitosan in Plant Defense Responses to Biotic and Abiotic Stresses
Chitosan, a copolymer of N-acetyl-D-glucosamine and D-glucosamine, which possesses properties that make it useful in various fields, is produced by the deacetylation of chitin derivatives. It is used in agriculture as a biostimulant for plant growth and protection, it also induces several responsive genes, proteins, and secondary metabolites in plants. Chitosan elicits a signal transduction pathway and transduces secondary molecules such as hydrogen peroxide and nitric oxide. Under biotic stress, chitosan can stimulate phytoalexins, pathogenesis-related proteins, and proteinase inhibitors. Pretreatment of chitosan before exposure to abiotic stresses (drought, salt, and heat) induces plant growth, production of antioxidant enzymes, secondary metabolites, and abscisic acid (ABA). It also causes changes in physiology, biochemistry, and molecular biology of the plant cells. However, plant responses depend on different chitosan-based structures, concentrations, species, and developmental stages. This review collects updated information on chitosan applications, particularly in plant defense responses to biotic and abiotic stress conditions.
Optimization of Partial Epoxidation on Jatropha curcas Oil Based Methyl Linoleate Using Urea-hydrogen Peroxide and Methyltrioxorhenium Catalyst
Natural epoxy fatty acids such as Coronaric acid (9,10-epoxy-12Z-octadecenoic acid) and vernolic acid (12,13-epoxy-9Z-octadecenoic acid) are rich in of Vernolia galamensis, Vernolia anthelmintica and Chrysanthemums coronanium. The two fatty acids each contains an oxirana ring and a double bond C = C. The oil or its derivatives are suitable for industrial usage as reactive diffluent of alkyd resins, plasticizers and stabilizers, surface coatings, surfactants and lubricants, as intermediates in chemical reactions for making linear epoxides of composite materials and polymers. However, the use of such oils on an industrial scale is impossible due to limited resources. Therefore, epoxidation reactions need to be carried out to overcome the demand for partial epoxide fatty acids. Partially epoxidation of methyl linoleate at room temperature (30°C) in the presence of pyridine, methyltrioxorhenium (MTO) as catalyst and urea-hydrogen peroxide (UHP) as oxidant was studied by using response surface methodology (RSM). A five-level-four-factors central composite rotatable design (CCRD) was used to optimize the partially epoxidation conditions and study the effect of MTO, UHP, pyridine and reaction time on relative conversion to oxirane (RCO). Quadratic polynomial model was employed to generate response surface plots for RCO. At optimal condition, 79.05% monoepoxide was formed at the RCO of 58.15% under condition of 0.75 mol% mole ratio of MTO, 300 mol% mole ratio of UHP and 9 mol% of pyridine at 120 min reaction time. It can be concluded that the effect of UHP mole ratios was the dominant factor to control the degree of partial epoxidation of methyl linoleate followed by mole ratio of MTO, reaction time and mole ratio of pyridine to formed methyl 12,13-epoxy-9Z-octadecenoate or/and methyl 9,10-epoxy-12Z-octadecenoate.
Evaluation of Forging Die Defect by Considering Plastic Deformation and Abrasive Wear in a Hot Forged Axle Shaft
In the hot forging process, an abrasive wear is a major problem in the manufacturing process which may possibly happen together with the plastic deformation. Both effects are difficult to distinguish in the real tooling. Finite Element Modeling (FEM) is a tool that use to simulate those phenomena in the hot forging process. However, some unknown factors are not directly obtained from the actual measurement. Thus, the sensitivity analysis is applied together with FEM to approximate those parameters. This research was to evaluate the die defects of the hot forged axle shaft process which were the plastic deformation and the abrasive wear. The reliable simulation modeling was developed by conducting the sensitivity analysis of the unknown parameters; heat transfer and friction coefficient, and compared the results with the experimental results. Then, the evaluation of the defects was performed by considering the effect of the plastic deformation and abrasive wear separately. The plastic deformation would be determined by comparing the effective stress with the yield strength of the die material at the same temperature. To predict abrasive wear in 3D space the die profile from the actual process was measured by CMM and then it was compared with that obtained by FEM. Archard’s model was used to predict the abrasive die wear in FEM. The variation of the K-values was significant to the wear prediction. According to this study, the average K-value obtained from different positions gives the best representative than considering only a single point K-value.
Feasibility of Using Natural Rubber (NR) Latex Foam as a Soft Robotic Finger: Role of Foaming Agent in Morphology and Dynamic Properties of NR Latex Foam
Sarcopenia caused by ageing and muscle loss is mostly found in the elderly people. Since a number of older people have been increased, a device which assists with grasping can play an important role in an ageing society. The purpose of this research is to select the material which is potentially a part of soft robotic actuator. Natural rubber (NR) latex produced locally in Thailand is intentionally chosen and chemically vulcanized by using a conventional vulcanization system into a molded fingered foam. The research focuses on varying the amount of foaming agent (Benzene sulfonyl hydrazide, BSH). Effect of foaming agent quantity on morphology and dynamic properties of the prepared natural rubber foam was elucidated. The suitable foam formula is selected and molded as the human fingers in the structure of a potential soft robotic actuator which were tested for the movement.
A Modified Strain-displacement Method for High Accuracy 8-Node Solid Finite Element
Higher-order three-dimensional solid elements are widely used for machine design and structural analyses. Although higher-order solid elements offer higher accuracy, the assembly routines often consume large amount of computational time and memory usage. In contrast, lower-order solid elements such as an 8-nod are simpler in programming implementation and consume less computational resources. However, they can produce problems of locking phenomena e.g. membrane and shear locking. Moreover, in a three-dimensional analysis using continuum solid elements, it is necessary to consider the stresses in the through-thickness direction, for example, in layered soil and foundation. This research aims to develop a modified strain-displacement finite element formulation that eliminates locking problems and generally applicable to both thick and thin threedimensional structures. The proposed formulation is based on the key concept of energy equivalence mapped between the global and natural curvilinear coordinates. The advantage of the proposed method is the ability to select a set of chosen strain functions that can be defined arbitrarily on the natural curvilinear coordinates.
The Performance of CUSUM Control Chart for Monitoring Process Mean for Autoregressive Moving Average with Exogenous Variable Model
The objective of this study was to derive explicit formulas for the average run length (ARL) of an autoregressive moving average with an exogenous variable (ARMAX(p,q,r)) process with exponential white noise on a cumulative sum (CUSUM) control chart. To check the accuracy of the ARL derivations, the efficiency of the proposed explicit formulas was compared with a numerical integral equation (NIE) method in terms of the absolute percentage error. There was excellent agreement between the two methods, but when comparing their computational times, the explicit formulas only required 1 second whereas the NIE method required 599.499–835.891 s. In addition, real-world application of the derived explicit formulas was illustrated using Hong Kong dollar exchange rates data with an exogenous variable (the US dollar) to evaluate the ARL of an ARMAX (p,q,r) process on a CUSUM control chart.
Enhancement of CO2 Adsorption Containing Zinc-ion-exchanged Zeolite NaA Synthesized from Rice Husk Ash
Carbon dioxide is main causes the greenhouse effect and it contributes to global warming. Zeolite NaA is an excellent adsorbent among other materials but its potential as a carbon dioxide adsorption still needs to be developed. Therefore, this research was to synthesize zeolite NaA from rice husk ash under different temperatures and crystallization times. The synthesized zeolite NaA was modified with zinc by an ion exchange method. Adsorbents were tested for the carbon dioxide adsorption at different operating temperatures and flow rates. The results showed that the zeolite NaA was successfully synthesized from rice husk ash under optimal conditions of the crystallization temperature at 333.15 K and time for 2 h. The zeolite NaA can be synthesized at low crystallization temperature and time resulted in this adsorbent has low cost while achieving high efficiency. The results of zeolite NaA modification with zinc playing a key role to increase the BET surface area, micropore volume and total pore volume resulted in an increase of carbon dioxide adsorption capacity. High carbon dioxide adsorption at 89.08% with the operating temperature at 573.15 K and carbon dioxide flow rate of 1 L/h were shown with 5 wt.% zeolite NaA.
Stability Improvement of Brake Disc to Mode Coupling at High Frequency Squeal
In this research study, the high-frequency squeal noise of a brake disc was found to occurred at a frequency of about 15 kHz. The potential root cause has been studied where mode frequency coupling and shape locking mechanism of brake disc and brake pads components are the main investigated topic. From the vehicle field test and the Dynamometer test, the braking condition, friction coefficient and braking pressure, have been confirmed to be used in numerical experiments. The updated finite element model (FEM) with the modal testing data of the existing brake components are formulated for the Complex Eigenvalue Analysis (CEA). In this study, the modification is based on in-board and out-board cheek thickness of the brake disc. Two of nine modifications of the brake disc cheek thickness are proposed with the method of separation the brake disc out-of-plane and in-plane modes and the method of avoiding shape locking between the brake disc and the brake pads modes. The constructed prototypes are verified with the vehicle field test and well agreed with the CEA.
Severity Estimation of Plant Leaf Diseases Using Segmentation Method
Plants have assumed a significant role in the history of humankind, for the most part as a source of nourishment for human and animals. However, plants typically powerless to different sort of diseases such as leaf blight, gray spot and rust. It will cause a great loss to farmers and ranchers. Therefore, an appropriate method to estimate the severity of diseases in plant leaf is needed to overcome the problem. This paper presents the fusions of the Fuzzy C-Means segmentation method with four different colour spaces namely RGB, HSV, L*a*b and YCbCr to estimate plant leaf disease severity. The percentage of performance of proposed algorithms are recorded and compared with the previous method which are K-Means and Otsu’s thresholding. The best severity estimation algorithm and colour space used to estimate the diseases severity of plant leaf is the combination of Fuzzy C-Means and YCbCr color space. The average performance of Fuzzy C-Means is 91.08% while the average performance of YCbCr is 83.74%. Combination of Fuzzy C-Means and YCbCr produce 96.81% accuracy. This algorithm is more effective than other algorithms in terms of not only better segmentation performance but also low time complexity that is 34.75s in average with 0.2697s standard deviation.
Using of Plastic Wastes as Additives in Bituminous Mixes
Plastic wastes are everywhere in today’s lifestyle and are growing rapidly specially in a developing country like Egypt. As these are non-biodegradable, there is a main issue facing the community concerning the handling of this plastic rubbish. On the other hand, different forms of increased distresses in flexible pavements such as cracking and rutting as well as moisture damage ratio should be faced and reduced by modifying the performance of hot asphalt mixtures. The reclaimed plastics that originally made of polymers have been used as an anti-stripping modifier to reduce the appearance of distresses in asphalt pavement surface and increase the resistance against moisture damage. In this research, the recycled plastic wastes have been used according to dry mixing process using contents (0.0, 2.0, 3.0, 4.0 and 5%) from the total weight of hot asphalt mixture. The optimal bitumen content has been derived for each polymer content by using Marshall procedure. The performance of modified bitumen mixtures have been recognized using Marshall quotient (as indicator of the stiffness), static indirect tensile strength and tensile strength ratio (as indicator of moisture damage resistance), dynamic modulus value (as indicator of stiffness of the asphalt mixture when tested in a compressive and repeated load test under different temperatures) and flow number (as indicator of permanent axial deformation resistance). The results obtained that the addendum of plastic rubbish to HMA improves its characteristics such as stability, strength, resistance to moisture damage and permanent deformation. The addition ratio of 3% polymer provides better pavement performance. Moreover, it has an economic importance where it reduces the exhaustion of natural asphalt in paving works by about 14.5%.
Microencapsulation of Thunbergia laurifolia Crude Extract and Its Antioxidant Properties
In this study, the antioxidant activity and total phenolic content of Thunbergia laurifolia Lindl. or Rang Chuet (RC) extracts from leaf, stem and rhizome were evaluated by using ferric reducing antioxidant power assay (FRAP) and the folin ciocalteu method for total phenolic compounds (TPC).The extracts were prepared by infusion using different amount of plant powder (2.5, 5.0, and 7.5 g) at different concentrations of ethanol as 0, 25, 50, and 75% and extraction time of 24, 48, and 72 h. The crude extract of 7.5 g leaf powder extracted for 72 h using water as the extraction solvent showed the highest antioxidant properties and total phenolic content. This extraction condition produced a FRAP content of 2.62 ± 0.01 mmol Fe2+/g that was significantly differed from those of the stem and rhizome and the highest TPC content of 877.36±18.75 (mg GAE/g). The crude extract from the leaf was subsequently encapsulated by using β-cylcodextrin (BCD) and maltodextrin 20DE (MD) as coating materials using freeze drying method. The encapsulated powder was investigated for its antioxidant activity. The highest encapsulation efficiency (EE) was obtained when only maltodextrin 20DE was used. The storage stability of encapsulated T. luarifolia leaf crude extract was then studied by storing the encapsulated powder at 35, 45, and 55°C for 5 weeks. The storage temperature had no effect on the stability of the encapsulated powder when TPC was used as the criteria unlike that of FRAP which was inconsistent during storage.
Effect of Reinforcements on Mechanical Properties of Nickel Alloy Hybrid Metal Matrix Composites Processed by Sand Mold Technique
Hybrid Metal Matrix Composites (HMMCs) have gained wide applications in aerospace, marine, and domestic areas because of its significant properties relative to external forces and enabling environment. In present research work, Ni-alloy selected as a matrix and Al2O3 of 40–80 μm and TiO2 of 1–5 μm were selected as reinforcements. The composites were prepared by keeping 9 wt. % of TiO2 as unvarying and Al2O3 is varied from 3 weight % to 12 weight % in steps of 3 weight %. Induction furnace is used for the casting of composites and mixing is done by using mechanical stirring at 160 rpm for a time period of 5 min. The prepared composites are then tested for their tensile and hardness as per the ASTM standards. The Scanning Electron Microscopy was used for microstructural study. From experimentation, it was observed that increment in the weight percentage of Al2O3 with constant TiO2 increases the mechanical properties of hybrid composites and proper stirring improves homogeneity in the composite material. The test results show that the addition of Al2O3 up to 9 weight percent increases in tensile strength compared to Ni alloy and tensile strength slowly decreases with the addition of Al2O3 and that the hardness values are directly proportional to the weight percent of the addition of Al2O3 / TiO2.
Input-output Linearizing Control of Strong Acid-base Neutralization Process with Fluctuation in Feed pH
This work presents a control system design for coupled control of pH and level with fluctuation in influent pH by manipulating influent and acid flow rates. A mathematical model based on the difference between proton and hydroxide ions estimated by the measured pH is introduced and applied in a formulation of the model-based control system. A feedback controller and estimated state disturbance are obtained by solving a minimization problem of squared errors between requesting input-output linearizing output responses and the reference setpoints. To eliminate the offset response, the estimated disturbance is applied in the calculation of the closed-loop compensator. The performance of the developed control system is evaluated in a bench-scale pH neutralization process of HCl-NaOH system, and it is also compared to that of a proportional-integral controller. The results show that the developed controllers could enforce a system with fluctuation in influent pH to the desired setpoints effectively, while the PI controller gave oscillation in outputs around the setpoints and cannot achieve the desired targets.
Designing of Double Acceptance Sampling Plan for Zero-inflated and Over-dispersed Data Using Multi-objective Optimization
The double acceptance sampling plan (DSP) is wildly used tools for the decision of production quality control. In actually, most production processes have excellent quality control and well inspected, the number of defective items for many samples will be zero. For this reason, the traditional probability distribution is not appropriate for the DSP. This research proposed the DSP for the manufacturing that was affected by zero-inflated and over-dispersed count data. The number of defects for a sample inspection is considered under the zero-inflated Negative Binomial (ZINB) distribution. The required sample sizes (n1, n2) are designed to achieve the optimal plan parameter of (n1, n2, c1, c2)* the DSP under the ZINB distribution (DSPZINB). The Genetic Algorithm with multi-objective optimization is used to estimate the optimal plan parameters which are maximizing the probability of accepting a lot (Pa) and minimizing the total cost of inspection (TC) and the average number of samples (ASN) simultaneously. The sensitivity analysis of the required sample size is used to analyze the performance of the proposed DSPZINB which is presented through three numerical examples. The results showed that a smaller of required sample sizes and n1 < n2 are provide the optimal plan parameters to achieve the minimum and maximum value of the multi-objective function. Moreover, the proposed DSPZINB give a good performance when a shape parameter of ZINB distribution (k) is small and approaches zeros while a zero-inflation parameter (ϕ) is a large value.
Crashworthiness Investigation of Multi-stage Structures Designed for Underrun Protection Devices
Due to the disparity between large trucks and passenger vehicles, most deaths in large truck crashes are occupants in small cars, which under-ride the large truck. To protect the under-riding of small vehicles during crash and mitigate the severity, various designs of underrun protection devices have been developed to be installed at the front, side, rear of trucks. Not only can underrun protection devices protect a small vehicle from under-riding a truck, but also minimize the severity of crash to develop crashworthiness. In this paper, various cross section patterns of underrun protection device guard bar are designed with the aims to improve the crashworthiness. Moreover, the crashworthiness capability is clarified for future design guideline. The proposed structural configuration is designed from the concept of multi-stage energy absorption, which also results in an improvement of bending stiffness. To investigate the crashworthiness of the proposed design, the dynamic analysis is performed in LS-DYNA explicit commercial finite element analysis package. The guard bar is cut partially and investigated by performing drop impact test. Energy absorption, specific energy absorption, peak impact force, crash force efficiency, and stroke efficiency are considered as quantitative criteria for crashworthiness evaluation. The technique of order of preference by similarity to ideal solution is adopted to perform a multi-criteria decision analysis and identify the overall performance score of each design. The results indicate that the triple stage UPD guard bar yields the best performance score and improve the overall crashworthiness score up to 10% as compared with the rectangular design of standard UPD guard bar.
Cover Vol. 13, No.4, October-December 2020
Cover Vol. 13, No.4 October-December 2020
On the New Weight Parameter of the Mixture Pareto Distribution and Its Application to Real Data
This research aims to investigate the theoretical properties of new distribution which are based on the preceding well-known distributions by adding the new weight parameter. The new distribution is called the new weight parameter of the mixture of Pareto distribution. The advantage of the new distribution is the right-skewed distribution that is depending on the shape parameter. This property made the new mixture of Pareto distribution have high benefits of reliability engineering and survival analysis. Besides, we applied the purposed distribution to three sets of actual data: cement industry data, hard drive failure data, and heart attack data to show that new mixture Pareto distribution is fit to real data for generating data models.
Optimizing Operating Conditions for Oxidative Coupling Methane (OCM) in the Presence of NaCl-MnOx/SiO2
A novel NaCl-MnOx/SiO2, synthesized using slurry mixed method, was used as a catalyst in oxidative coupling of methane process. Optimal conditions were determined using both computational and experimental methods. NaCl, MnOx and SiO2 which are the component of our catalyst are studied. In this research, the catalyst provided the best experimental result when the ratio of MnOx to SiO2 was 2 to 1. CH4 conversion, C2+ selectivity, C2+ yield and C2H4/C2H6 ratio were achieved at 38%, 71%, 27% and 7.2, respectively when operated the process at optimal temperature of 750°C under atmospheric pressure with ratio of CH4:O2 at 4 and 3000 mL g–1 h–1 of weight hourly space velocity (WHSV). The catalytic performance of NaCl-MnOx/SiO2, was found to be higher than other recently developed catalysts. Besides, NaCl-MnOx/SiO2 gave only less than 10% selectivity of the unwanted CO2, while the other SiO2-based catalysts reported as high as 17% of CO2 selectivity. It also achieved high ethylene production when benchmark with previous research. The experimental results were validated using Aspen Plus at temperature ranging from 700 to 850°C.
P2CTS-3D IC: An Efficient Placement Aware Partitioning and Clock Tree Synthesis in 3D-Integrated Circuits
The three dimensional integration of electronic circuits (3D-ICs) is one of the most promising approaches to encounter eternally increasing demands of functionality, performance, and power consumption. However, there exist many challenges in the minimization of power dissipation, skew, latency, wirelength, and obstacle avoidance in 3D-ICs. To overcome the discussed problems, an efficient placement aware partitioning and synthesis by clock tree have been proposed in 3D-ICs. In the proposed framework, the first process begins with the partition of netlist into multiple layers using hybrid Chemical Reaction Optimization (CRO) and K-Medoid algorithm and the placement process has been executed using Grid Warping Technique (GWT). Then, the routing process has been performed using the Line Search (LS) algorithm. The clock tree synthesis process gets accomplished with a Density Sorting (DS) algorithm that considers multiple TSVs. Further, the Clock tree topology has been implemented using the algorithm of Merging with Defer and Embedding (DME) and the algorithm of Graph with Neighbor at the Nearest. Consequently, the buffering and the embedding processes have been carried out to measure the total power dissipation and timing parameters. The proposed work minimizes the skew value compared to the other existing methods like GAP, EP, and SEA and it also provides efficient clock tree synthesis with Defer Merging and Embedding (DME) and Nearest Neighbor Graph (NNG) algorithm based methods as well as it reduces the skew optimally. Finally, the performance of the proposed work has been evaluated and proved to be better by considering the following metrics such as wirelength, power, skew, latency, and area.
Industry 4 and the Future of Smart Manufacturing
Piper Trilinear and Gibbs Description of Groundwater Chemistry in Port Harcourt, Nigeria
Several studies have shown that there are high salinity values in the groundwater quality in certain areas within Port Harcourt city. However, a detailed investigation on the cause is not yet documented hence, this research investigated the factors governing the hydro-geochemistry of the said area. This was achieved by analysing concentrations of 7 ions (both cations and anions) and total dissolved solids (TDS) in water samples obtained from 26 drilled boreholes and 4 hand dug wells, evenly distributed within the study area. The examined ions are Ca2+, Mg2+, Na+, K+, Cl-, HCO3- and SO42-. Laboratory results were plotted on Piper trilinear and Gibbs diagrams through Aquachem 5.1 software package and it was revealed that 63.33% of the total samples fell in Na-Cl hydrochemical facies while the remaining 36.67% occurred in Ca-Cl facies. It was also revealed that the controlling factors for formation of the analysed ions were precipitation and rock weathering on 76.67% and 23.33% respectively. Hence, it was concluded that Na-Cl facies is the dominance hydrochemical facies in the study area while the main factor governing the formation of ions is precipitation. However, it was recommended that the rate of pumping out water from wells in certain parts of the study area should be reduced in other to avoid seawater intrusion.
Recent Situation and Progress in Biorefining Process of Lignocellulosic Biomass: Toward Green Economy
Towards the rising trends of Bio Economy, Circular Economy and Green Economy (BCG economy) concept, biorefining process has been developed continuously to improve the utilizations of unused lignocellulosic biomass to produce value-added chemicals and products. During the early era of biorefining process, the major focuses of biorefining products were dedicated to biofuels, especially bioethanol and biobutanol due to the coherent situation of rising crude oil price. Currently, the targeted products of biorefining processes are directed to platform chemicals, which their purposes are not limited to fuels, but are expanded to various downstream industries. However, most of developed processes are still unable to overcome the numbers of concerns, especially economic issue and scaling up technology. This review explores the recent pretreatment technologies of lignocellulosic biomass and addresses the direction of development to provide the updated situation of biorefining process for peer-researchers and related industries.
Influence of Nitrate-nitrite Contamination on Pink Color Defect in Ginger Marinated Steamed Chicken Drumsticks
This study aimed at investigating influence of nitrate-nitrite contamination in ginger on pink color defect in marinated steamed chicken drumsticks. Three marinade formulations representing different degrees of nitratenitrite contamination were explored (i.e. no ginger (0 ppm) – A, ginger paste #1 containing 30 ppm nitrate – B, and ginger paste #2 containing 30 ppm nitrate + 8 ppm nitrite – C, respectively). Total myoglobin content was measured in chicken drumsticks before marination. Nitric oxide myoglobin (NOMb) was determined in the samples both before and after marination. After cooking, occurrences of pinking, a* value and nitrosyl hemochrome (NHC) content were evaluated. It was found that pink color defect was observed in treatment C. These results indicated that the presence of nitrite in ginger (treatment C) played a significant role in pinking appearance of steamed chicken drumstick. The maximum nitrite contamination in chicken drumstick was also investigated using sodium nitrite solution and it was found that it should not be more than 0.8 ppm. Thus, it is crucial to control the amount of nitrite contamination in ginger paste to avoid pink color defect formation.
Heat Loss Analysis of Continuous Drying Oven with Outside Conveyor Chain
In continuous manufacturing lines, conveyor chains are employed to transport future products in and out of these ovens in various processes of the production. As such, the typically metal conveyor system creates a significant heat loss by absorbing the thermal energy from inside the oven and releasing it outside. This work analyzed heat transfer of a novel drying oven design with their conveyor chains outside of the heated zone. The problem was complex due to multiple modes of heat transfer and an intermediate area between the heated zone and the outside chain. A mathematical model was proposed along with a numerical solution approach based on Finite Difference Method (FDM). Using problem parameters from a real latex-gloves production line as an example, it was found that the new design could reduce the heat loss by 23.1% when replacing all conventional ovens with the new designs.
Numerical and Physical Investigation of the Mixing Process in Gas Stirred Ladle System
Secondary steelmaking or ladle metallurgy is one of the important processes that adjust and homogenize the chemical compositions and the temperature. In this process, argon gas is injected into the melt through porous plugs to accelerate the chemical reaction and the mixing. One of the indicators for the mixing efficiency is “the mixing time”. The purposes of this study were to investigate the effects of gas flow rate and purging system on the mixing time and flow characteristics by using numerical and physical investigation and to predict the velocity magnitude acting on the refractory wall by analyzing the effects of gas flow rate. A 1:5 scaled water model and a full-scale ladle model of Millcon steel PLC were used in the study. The numerical simulation modelling was carried out by using CFD commercial software Flow-3D. The results from the numerical simulation were in consistence with the experiment results. The simulation results showed that with the highest gas flow rate the reduction of the mixing time was around 36% and the velocity magnitude increased to approximately 44% in comparison with the lowest gas flow rate in the full-scale model. The area at the ladle wall near the liquid surface has a higher chance of the damage than other areas. Besides, employing the dual-plugs system led to approximately 33–49% shorter mixing time compared to the single-plug system. The results show that the gas flow rate affects the turbulent kinetic energy directly. However, high turbulent kinetic energy leads to open-eye size which results in re-oxidation and contamination. Therefore, it is important to optimize the flow rate to achieve both productivity and steel cleanliness.
Energy, Economic and Environmental (3E) Analysis for Sustainable Development: A Case Study of a 9.9 MW Biomass Power Plant in Thailand
In Thailand, the use of biomass for electricity generation has been implemented with incineration technology for many years. However, recent reports indicate that electricity demand is still high and biomass power plant is one of the key factors for electricity management. The major purpose of this research paper is to analyze the energy, economic and environmental features of biomass power plant for the national sustainable development strategy. An existing 9.9 MW biomass power plant located in Suphanburi is selected as the case study to assess thermal combustion for electricity generation. The in-house operations of biomass-based power plant and the process flow of energy in terms of electricity generation using agricultural wastes and forestry residues are provided. Different expenses like capital cost, processing cost, and transportation cost and the major revenue from the sale of electricity are taken into consideration. Five environmental factors (air, sound, water, ash, and transportation) of biomass power plant for sustainability are investigated. Findings from this research project indicate that incineration is a suitable technology for biomass-based electricity generation with considerable profit for all stakeholders.
Hybrid Control Scheme for Anaerobic Digestion in a CSTR-UASB Reactor System
Anaerobic digestion is an important wastewater treatment technology for industrial wastewater. To achieve the target of global environmental regulation, process control plays an important role in the system operation. The control system for anaerobic digestion process is generally applied to each reactor separately without consideration of variables that mutually affect the operation of the other one. This work proposes a hybrid control scheme for a CSTR-UASB reactor system described by a PDE-ODE model. The CSTR system is employed to rapidly reduce the inlet COD concentration while the UASB reactor is used to accurately regulate the outlet COD concentration of the system. An input-output (I/O) linearization and proportional-integral (PI) control techniques are applied to formulate the control scheme for the process. The distributed variables are applied to the developed control system for handling the spatially distributed dynamics of the bacterial biomass. The COD concentration of both reactors are manipulated through the dilution rate and feed flow rate to achieve the desired targets. Simulation results of the closed-loop system illustrate that the developed control scheme regulates the controlled outputs to follow the desired trajectories and manipulate the control problems effectively.
Statistical Inference on the Ratio of Delta-Lognormal Coefficients of Variation
The coefficient of variation is useful to measure and compare the dispersion of the data when different units are used in different datasets. This article aims to propose new confidence intervals for the ratio of two independent coefficients of variation with delta-lognormal distribution. The proposed methods include the concept of the generalized confidence interval and the method of variance estimate recovery. They are applied with three methods, variance stabilizing transformation, Wilson score method, and Jeffreys method. The performance of the confidence intervals was assessed by the coverage probabilities and the expected lengths via the Monte Carlo simulation. The outcomes of the simulation study showed that the generalized confidence interval is appropriate to construct the confidence interval for the ratio of delta-lognormal coefficients of variation. Two rainfall datasets from Nakhon Ratchasima, Thailand are used to demonstrate the proposed confidence intervals.
A Comprehensive Review on Effects of Nanoparticles-Antioxidant Additives-Biodiesel Blends on Performance and Emissions of Diesel Engine
The present review investigates the effects of different nanoparticles and antioxidants blended with biodiesel on the diesel engine’s performance and emission characteristics. Biodiesel usage in diesel engine decreases the dependence on imported petroleum and yields benefits like reduction in global warming and engine exhaust emissions. However, inherent drawbacks like lower calorific value (CV), higher density, and viscosity while increased fuel consumption and nitrogen oxides (NOx) emissions limit the biodiesel application in engines. In this way, the additives in the form of nanoparticles of different materials and antioxidants play a prominent role in mitigating the drawbacks of biodiesel. This review paper focuses on the effect of various additives in the form of nanoparticles and antioxidants blended with biodiesel on engine performance and emission characteristics. Biodiesel blended with additives reveals that the reduction of carbon monoxide (CO), unburnt hydrocarbons, and NOx emissions and also improvement in brake thermal efficiency (BTHE) and brake specific fuel consumption (BSFC) as compared to diesel and neat biodiesel. The comprehensive review suggests that nanoparticles of different materials and antioxidants blending with biodiesel improved its characteristics and also establish an optimum improvement in engine performance and emission characteristics.
Green-composites: Ecofriendly and Sustainability
Comparison of the Flow Behaviours of Physical and Numerical Models on a Stepped Spillway
A massive water release can create high discharge and high velocity, which in turn can lead to erosion at the surface of a spillway. The difficulties of data collection and the high cost of experiments impose barriers to the study of large spillways. A numerical model that can simulate the flow behaviour is a valid choice to solve this problem. The objective of this research is to study the flow behaviour and flow velocity triggered by physical model tests and numerical model simulations. The small differences between the results of the two models illustrate that the numerical model is reliable and can be used to design a stepped spillway. Computational fluid dynamics (CFD) is a numerical modelling technique used in this study. For the numerical modelling of turbulence, the k–epsilon turbulence model is used. This model comprises 3 submodels: The standard k–epsilon, renormalized group (RNG) k–epsilon and realizable k–epsilon models. The results show that the RNG k–epsilon model is the most suitable model. The results reveal that the stepped spillway results in a 98% reduction of energy dissipation based on the present case study. The quantified differences between the results of the physical model and those of the numerical model are approximately 0.1–11.23%.
Natural Language Interface to Database for Data Retrieval and Processing
Though many studies related to natural language interface to a database have been conducted for many years, the results of these studies are not covered in many used cases such as the use of negative sentences, processing functions, and variety of sentence patterns with various types of query specification. To solve these problems, a model called “Natural Language Processing for Data Retrieval and Processing (NLP-DRP)” was proposed. A new algorithm named ‘Ranking Trie’ was implemented with the combination of Pattern Parsing, Ontology, and Fuzzy system to improve Lexical analysis, Semantic analysis, and Output transformation processes to allow users to retrieve and process data with various patterns of sentences and conditions. The model was incrementally tested and updated by a Learning dataset collected from users with a total of 3,868 Natural Language Query Sentences (NLQSs) then finally evaluated by the test dataset with a total of 500 NLQSs. The results showed that the NLP-DRP could retrieve data, processed, and generated outputs which consistent with user requirements with all values of Accuracy, Precision, Recall, and F-measure higher than 0.9.
Mannanase and Cellulase Enzyme Production from the Agricultural Wastes by the Bacillus subtilis P2-5 Strain
The objective of this research was to use agricultural wastes as substrates in enzyme production processes, instead of using a commercial substrate named locust bean gum (LBG), in order to determine an alternative way of managing agricultural wastes, to reduce waste disposal costs, and to reduce enzyme production costs. There are four potential factors generally considered in enzyme production, which are designated as a substrate, an inoculum, temperature, and an incubator shaker speed. In this research, three agricultural wastes, namely tea waste, coffee grounds, and copra meal were considered as substrates. A new bacterium that was isolated from the soil named Bacillus subtilis P2-5 was considered as the inoculum, and it was tested at 1 and 5% (v/v). A factorial experiment was then conducted, in order to study the effects of these factors and their interactions on mannanase and cellulase activities. The results showed that the three wastes can be used as substrates to produce mannanase and cellulase. Tea waste obtained the highest enzyme activities when compared to coffee grounds and copra meal. The optimal condition to maximize both of the mannanase and cellulase activities was to use tea waste, 1% (v/v) of inoculum, 37°C, and 150 rpm. Although the enzyme activities obtained from the tea waste were lower than those obtained from LBG, the proposed idea is still recommended, since benefits from these agricultural wastes can be obtained, rather than merely casting them aside.
Impact of Fermentation Conditions on the Extraction of Phenolics and Sensory Characteristics of Mangosteen Wine
Phenolics play a major role in determining the quality of wine. This study focuses on the impact of fermentation conditions (varying pericarp content: 0, 5, 7.5, and 10% (w/v); Saccharomyces cerevisiae strain: Montrachet-UCD #522 and Pasteur Red-UCD #904) on the extraction of phenolics and sensory characteristics of mangosteen wine at 30 ± 2°C. The addition of pericarp showed a significant effect on color intensity, but the choice of strain of yeast used has no effect. With increasing percentage of pericarp added, the amount of phenolics, tannins, and anthocyanins increased, with the highest total phenolic content to be 4,000 mg/L catechin equivalent at the end of fermentation. At lower percentage of added pericarp, the yeast induced no apparent difference to the sensory characteristics, but at higher percentage the difference was more apparent. Wine with lower percentage of pericarp added had higher intensity of mangosteen pulp flavor, whereas wine with higher percentage of pericarp has more mangosteen pericarp characteristics. Pasteur Red contributed to a higher degree of fruity and floral aroma/flavor, while Montrachet contributed to a more intense body.
A Comparative Study between the Seven Types of Fuel Cells
In the new era with advanced technologies, fuel cell has been widely used as source of power both for portable and stationary applications. The application has become more popular nowadays as it is an eco-friendly device and has no noise due to absence of rotating components. Fuel cells are designed with high efficiency compared to conventional energy sources. However, the benefits have come with weaknesses and threats that might deter its prevalent application. This paper is, therefore, aimed at comparing the seven mainly used fuel cells. The SWOT analysis of the fuel cells are also presented separately, and the pros and cons of each cell were summarized.
Virtual Reality Technology for Maintenance Training
This paper is part of a bigger research project that aims at establishing an integrated VR environment for preparing, evaluating, and executing maintenance training in virtual environments. In order to apply the virtual reality technology to maintenance task training, this paper presents a Virtual Reality for Training in Maintenance Task (VR-TMT) platform using the simulation of the process of a gearbox disassembly and assembly as an example. The system setup and configuration are presented in detail, as well as the analysis of the experience, perception level and side effects of using VR devices. The results show that the user experience and perception levels on provided by the VR-TMT platform are on a good level. In addition to that, the VR-TMT system is easy to use, understand and flexible for transport. Users can therefore profit from the VR-TMT platform to train anywhere and anytime according to their needs. The majority of the experimental users experienced only few side effects, in particular both physical and visual tiredness. However, the experiment confirmed that the immersive experience of VR-supported maintenance task training outweighs the reported side effects.
Effect of Spray Drying Air Temperature to the Changes of Properties of Skimmed Coconut Milk Powder
This study investigated different conditions for producing suitable skimmed coconut milk powder using spray drying process. Skimmed coconut milk is a by-product of the virgin coconut oil extraction process. The skimmed coconut milk was composed of 6.4% protein, 0.27% fiber, 6.27% sugar, 3.6% fat and 86.93% moisture content. Spray drying involved an inlet flow rate of 0.27 m3/s, temperatures between 190 and 210°C and the use of 15 and 20% maltodextrin as drying aid. As inlet and outlet temperatures increased, the product yield, moisture content, bulk density and wettability reduced. The particle size of skimmed coconut milk powder was found to be 250 μm. The average percentage of solubility of the skimmed coconut milk powder in the current study was 39.57%. The amino acid content analysis was carried out using the HPLC method to reveal the glutamic acid and arginine acid as non essential amino acid. The color of skimmed coconut milk powder at high inlet temperatures caused significant changes in L* and b* and high maltodextrin concentrations caused significant changes of a* (p < 0.05). The optimum yield of skimmed coconut milk powder was 18.65% when using 20% maltodextrin with an inlet temperature of 190°C and an outlet temperature of 80°C for spray drying.
Effect of Hemicellulase Enzyme in Flotation Deinking of Laser-printed Paper
Deinking is one of the most important steps in paper recycling process. Novel deinking method such as emzymatic deinking has grown more and more important in environmentally friendly paper recycling. The aim of this work was to investigate the effect of hemicellulase enzyme on the efficiency of ink removal from laser-printed paper in flotation deinking process. The influence on pulp and mechanical properties of deinked paper such as freeness, tensile index and tear index are also studied. The experiments performed at the dosages of hemicellulase enzyme from 0 to 0.15% with the concentration of nonionic surfactant (Tween-80) of 1.75% (Base on oven-dried weight of paper). The results obtained in this work revealed the enhancement of ink removal efficiency (11.3–95.3%), as indicated by the decreasing of the effective residual ink concentration (ERIC) as compared to non-deinked paper. Moreover, the results showed the improvement in freeness (3.7–13.2%), tensile index (5.2–18.1%), and tear index (19–25.6%) with respect to the control condition obtained with the absence of enzyme. These improvements were achieved considerably after flotation process but tended to drop down when the dosage of enzyme was too much. The maximum deinking efficiency (about 95%) was found at 0.1% hemicellulase enzyme (based on oven-dried weight of paper) which the mechanical properties after flotation deinking process increased about 25% and 18% in tear index and tensile index, respectively, as compared to control.
Purification and Characterization of a Novel Bacteriocin Against Vancomycin Resistant Enterococci Produced by Enterococcus hirae HM02-04
Enterococcus hirae HM02-04 isolated from breast milk exerted growth inhibition against especially vancomycin resistance enterococci (VRE). The aims of this study were to purify and characterize the antimicrobial substance produced by the strain HM02-04. One active peptide was successfully purified by 3 steps of Amberlite XAD-16 adsorption-desorption, cation exchange chromatography, and reverse-phase HPLC. It had 2605.298 Da peptide by MALDI-TOF MS analysis. The peptide sequence determined by LC-MS/MS contained only 23 amino acid residues providing the molecular mass of 2312.67 Da by in silico analysis. However, its amino acid sequence obtained showed no homology to other bacteriocins including enterocins previously reported and proposed as a novel one named Hiracin HM02-04. This is the first report to discover E. hirae isolated from breast milk that was able to produce a bacteriocin against VRE. Hiracin HM02-04 was stable at a high temperature of 121°C for 15 min and at a wide pH range of 3–9. It was sensitive to actinase E, pepsin, proteinase K and trypsin. The Hiracin HM02-04 has the narrow inhibition spectrum and no inhibition against Listeria. This bacteriocin was also found to have a bactericidal mode of action with concomitant cell lysis against the strain VRE 426. The present research addresses Hiracin HM02-04 as a promising alternative to conventional antibiotics in the treatment of enterococcal infections.
The Influence of Manganese Oxide on the Densification and Mechanical Properties of 3Y-TZP Ceramics
With outstanding integration of mechanical performances and biocompatibility, 3 mol% of yttria stabilised tetragonal zirconia polycrystals (3Y-TZP) ceramic are extensively fabricated as biomedical implants. Conventional sintering (CS) was generally employed to produce 3Y-TZP bodies with promising densification, which resulted in grain coarsening and mechanical properties deterioration due to elevated sintering temperatures (> 1500°C). The main weakness of 3Y-TZP ceramic is the spontaneous tetragonal to monoclinic phase transformation under humid environment, which is known as low-temperature degradation (LTD). In present work, undoped and MnO2 (0.3 and 0.5 wt%) doped 3Y-TZP green bodies were prepared and subjected to CS at 1200–1500°C for an hour of dwelling time. It was found that the optimum concentration of MnO2 dopant was 0.5 wt%. Reasonable toughness values of 5–7 MPa.m1/2 revealed the tetragonal phase stability of 3Y-TZP grains was not altered by doping of MnO2. Moreover, outstanding density level of > 96% of 0.5 wt% MnO2 doped 3Y-TZP ceramics demonstrated the superb Young’s modulus of > 200 GPa and Vicker’s hardness of >13 GPa. Fabrication of 3Y-TZP by doping MnO2 had reduced the total processing time by ~ 9% and sintering temperature by up to 150°C when compared to undoped 3Y-TZP ceramics sintered at 1400°C.