Engineering and Applied Science Research

Towards the decarbonization of residential buildings through roof External Thermal Insulation (ETI) in arid zones: A case study

Imane Benoudjafer — 2024-11-18

The objective of this article is to present a range of effective thermal insulation techniques for flat roofs, based on natural insulating materials, in order to reduce excessive energy consumption used for heating and air conditioning, improve the thermal comfort of occupants, reduce the high costs associated with energy bills, and minimize the emissions of harmful CO₂ gas from buildings. In this context, the methodology followed involves studying an existing residential apartment located in an arid region. To do this, three combinations of external thermal insulation systems (ETI) have been proposed: a hot roof system, an inverted roof system, and a combined roof system, supported by a numerical simulation carried out with natural-based thermal insulation systems (wood fiber and expanded cork). Subsequently, an economic study was conducted for all the tested systems. The numerical results obtained show that the combined roof thermal insulation system, with double insulation using wood fiber (3 cm) and expanded cork (4 cm), is the optimal solution, yielding savings of 7736.83 DZD per year. Additionally, the reduction in energy consumption (kWh/m². year) and CO₂ carbon emissions (kg/year) were approximately 52.34% and 40.65% respectively.

The improvement of germination method for producing the germinated brown rice using a water spraying system with a revolved sieve

Thatchapol Chungcharoen — 2024-11-19

Water soaking is an important method in germinated brown rice (GBR) production that causes fermentation, leading to an unpleasant smell of GBR. In this research, a water spraying system with a revolved sieve is applied to produce the GBR. The increased speed and time of spray break led to higher moisture content and water absorption. The spray break of 30 min and revolved speed of 15 rpm provided the shortest time to obtain the paddy with a moisture content of 30% (w.b.). The incubation pattern with a revolved sieve and water spray provided the shortest incubation time for 90% germination. When producing the GBR with a water spraying system with a revolved sieve (GBR-WSSRS), it had a lower number of microorganisms compared to the GBR with a water soaking (GBR-WS), leading to higher scores of overall acceptability. However, the GBR-WSSRS had a lower GABA content than the GBR-WS.

Effect of steel slag and ceramic residues on the physical and mechanical properties of concrete

David Olivert Chapoñan Mondragón — 2024-11-13

Cement is a critical component in concrete, but it significantly impacts the environment from extraction to disposal, depleting resources and generating pollution. To address this issue, the use of steel slag (SS) and ceramic waste powder (CWP) was investigated as partial replacements for cement at 8%, 10%, 12%, and 15% by weight. Various mixtures were evaluated, including a control mix with a water-to-cement (w/c) ratio of 0.52, mixtures containing SS, and an optimal blend of SS with different proportions of CWP. Physical and mechanical properties were assessed through slump tests, temperature measurements, air content, and density evaluations. Compressive strength, flexural strength, tensile strength, and modulus of elasticity were also analyzed at 7, 14, and 28 days using standardized cylindrical and prismatic specimens. The results indicated a reduction in slump and temperature of the concrete by up to 45.87% and 9.10%, respectively, with a slight increase in density and air content when incorporating 10% SS and 15% CWP. In terms of mechanical properties, the optimal substitution of 10% SS improved compressive strength by 7.39%, modulus of elasticity by 13.06%, flexural strength by 8.22%, and tensile strength by 14.10% compared to the control mix. The hybrid mix of SS and CWP (10%:10%) showed significant enhancements: compressive strength increased by 17.12%, flexural strength by 19.25%, tensile strength by 26.28%, and modulus of elasticity by 21.21%. It was concluded that substituting 10% SS and 10% CWP by weight of cement enhances the mechanical properties of concrete, promoting efficiency and sustainability in environmentally friendly construction. This hybrid concrete can be effectively used in pavements, sports floors, sidewalks, and curbs.

Briquettes fuel production from sugarcane bagasse for sustainable community energy solutions

Suntorn Suttibak — 2024-10-01

The objective of this study is to determine optimum conditions for producing briquettes fuel from biomass, examine the properties of the resulting briquette fuel and transfer the technology to target communities. The production process entails implementing a screw-type briquette press equipped with controlled temperatures through a molded pipe clamp electric heater for shaping the briquettes. This is an innovative approach that allows briquettes to be produced and ready for use in a single step, while other processes require the briquettes to be dried first. The production capacity was estimated to be 12 kg/hr. Bagasse, a byproduct of sugarcane processing, was the biomass used in the current research. For this study, four distinct temperatures were chosen for experimentation, 100, 110, 120, and 130°C. The proportions of bagasse, cassava flour, and water were investigated for briquette production utilizing two formulae: 1 kg bagasse to 0.1 kg cassava flour and 0.5 liters water, and 1 kg bagasse to 0.3 kg cassava flour and 0.5 liters water. The findings indicated that bagasse briquettes could be effectively manufactured at 120°C. The ideal proportion of bagasse particles, cassava starch, and water was 1 kg : 0.3 kg : 0.5 liters, respectively. The moisture content, volatile matter, ash, and fixed carbon were respectively 8.04, 70.20, 13.05, and 16.11 wt.% on a dry basis, based on the physical and chemical property tests of the briquette fuel. The material has a density of approximately 856.70 kg/m³, a compressive strength of 89.34 kg/cm², and a higher heat value (HHV) of 24.05 MJ/kg, with a longer burning time than regular charcoal. The research emphasizes using bagasse for innovative renewable energy production technologies and disseminating this technology in target communities in Thailand.

Integrated neural network-based MPPT and ant colony optimization-tuned PI bidirectional charger-controller for PV-powered motor-pump system

Rati Wongsathan — 2024-09-04

This study presents the design and implementation of an efficient off-grid photovoltaic (PV)-powered motor-pump system utilizing a two-stage power converter. The system integrates a neural network-based maximum power point tracking (MPPT-NN) algorithm with a proportional integral (PI) controller and an additional bidirectional PI charger. Controller gains are optimized using ant colony optimization (ACO) to achieve optimal performance. The proposed MPPT-NN-PI/ACO controller enhances control responses and improves energy utilization efficiency by 17% compared to traditional PI controller. Performance comparisons of MPPT techniques demonstrates that the proposed controller outperforms several existing methods, including commercial on-off controllers, the modified Perturb & Observe algorithm, and neural network-based controllers, by approximately 4%–20%. It shows a slightly different performance of about 1%–6% compared to advanced adaptive controllers, including fuzzy logic and neuro-fuzzy controllers. For bidirectional charger performance, the DC bus voltage connecting the boost converter and bidirectional converter remains stable with small ripples and is well-aligned with the reference voltage, ensuring uninterrupted operation under varying weather conditions. The bidirectional charge management effectively maintains battery state-of-charge (SOC), showing a decline during periods of insufficient PV energy and achieving full charging during periods of excess PV energy. System performance is validated through both simulation and laboratory-scale prototyping, ensuring robust operation.

Effects of spray drying chicken feather keratin with Arabic gum encapsulation for nutrient supplementation

Vanessa Alberto — 2024-11-07

Keratin has always been a topic of interest as a novel protein source in human nutrition, consistent with waste-to-wealth initiatives. Hydrolyzed chicken feather keratin is spray-dried to facilitate storage, transportation, and development into dietary supplements. High-heat drying, however, may affect the quality and function of this bioactive compound. The objective of this research is, thus, to determine the suitable spray-drying parameters involving inlet temperature (70 – 190 °C), feed flow rate (3 – 9 ml/min), and concentration of Arabic gum (AG) (0 – 5%w/v) for the encapsulation of hydrolyzed chicken feather keratin as a nutrient supplement. The effects of the spray-drying on powder yield, moisture content, flowability, and total protein content were investigated. Fourier Transform Infrared Spectroscopy (FTIR) determined the presence of functional groups, while Scanning Electron Microscope (SEM) investigated the powder morphology. High Performance Liquid Chromatography (HPLC) was also conducted to obtain amino acid profiling of the powder. Then, capsule quality control tests were done to ensure compliance with industrial standards. Good powder quality was obtained from the parameters of inlet temperature 190 ± 5°C, feed flow rate of 3 ml/min and AG concentration of 2.50% since it showed high yield of 81.88%, moisture content of 3.74% (<5%), flowability with AOR 43.70° (<50°), high (minimal lost) total protein content of 0.7168 g protein/g solid. The keratin functional groups remain distinguishable through FTIR with AG encapsulation. SEM showed spherical and intact structures, which suggests high integrity of encapsulating materials. Amino acid profiling confirmed the presence of essential and non-essential amino acids, which are important as building blocks of proteins in the body. The product met all capsule quality control standards according to National Pharmaceutical Regulatory Agency of Malaysia (NPRA) and United States Pharmacopeia (USP). This result showed that spray-drying hydrolyzed keratin in the presence of AG would retain its function and powder quality.

Optimizing mushroom classification through machine learning and hyperparameter tuning

Hamidah Maulida Khasanah — 2024-09-25

This research explores the application of machine learning in the classification of mushrooms as poisonous or edible, emphasizing the importance of optimal model performance to ensure food safety. This study compares four classification algorithms-Random Forest, Logistic Regression, Decision Tree, and Naive Bayes-before optimizing the two best models through Hyperparameter Tuning using Grid Search. The proposed method involves Exploratory Data Analysis (EDA), Data Preprocessing, Classification Modeling, Performance Evaluation, and Hyperparameter Tuning. The dataset used is Mushroom Classification data, and the results show that the Random Forest algorithm performs better with ROC values close to 100%, high recall, and good F1-Score. Hyperparameter tuning further improved the ROC and recall of the Random Forest model, emphasizing its adaptability to the nature of the dataset. This research emphasizes the importance of robust data processing and model optimization to achieve accurate and reliable predictions in mushroom classification, contributing to food safety endeavors.

Application of strategic environmental assessment for mass transit system: Case study of Uttaradit Province, Thailand

Pitsanu Pannaracha — 2024-07-17

This research aims to apply Strategic Environmental Assessment (SEA) at the strategic action. Plan and program of the mass transit system in Uttaradit province, Thailand. Some steps of SEA process were applied to such strategic action by focusing on the development and assessment of the appropriate alternatives together with the selected appropriate indicators. The alternatives for mass transit development plan were proposed as following; Alternative 1: No Development Plan (or No Action Plan), Alternative 2: Conventional Mass Transit System Development Plan (Conventional Plan), Alternative 3: Smart and Environmentally Friendly Mass Transit Development Plan (Smart plan). With the Pairwise Comparison and the Impact Matrix Analysis, the Smart Plan was assessed as the appropriate alternative when compared with the Conventional Plan and No Action Plan as for 49.36%, 32.17%, and 18.47 % respectively. The mass transit system under the Smart Plan were proposed as Road, Railway, and Road with Railway systems. On the same assessment procedure, the impact score of the Road with Railway, Railway and Road system were 36.64 %, 33.90% and 29.46% respectively. The appropriate alternative mass transit system was road and railway system. SEA was practical tool applied to the strategic level of the mass transit development.

Serum glycobiomarker mining suggested the improvement of cholangiocarcinoma detection using combined CA125 and CA242

Kodchakon Lekkoksung — 2024-08-06

Cholangiocarcinoma (CCA) is a malignant neoplasm originating from biliary epithelial cells. During the early stage, the patients do not show any symptoms, leading to wide and extensive spread of this disease. Nowadays, there has not been a single serum tumor marker which can be used for effective screening of the disease or classification of the patients. This study therefore aims to determine an appropriate serum marker for screening of the patients with early staged CCA by using a technique of data mining. Beginning with the C4.5 Decision tree and Logistic Regression for selection of serum markers for effective screening of the patients with CCA, the selected markers were then used for classification of the patients with CCA from non-CCA patients, and CCA from Benign Biliary Disease (BBD) by C4.5 Decision tree, Logistic Regression, Random Forest, and Artificial Neural Network. In this work, seven serum tumor markers were used, including Carbohydrate Antigen 125 (CA125), Carbohydrate Antigens 19-9 (CA19-9), Carbohydrate Antigen 242 (CA242), Carbohydrate Antigen 50 (CA50), Carbohydrate Antigen 72-4 (CA72-4), Carcinoembryonic Antigen (CEA), Cy-tokeratin-19Fragment (CYFRA 21-1). The model was used to classify the CCA and non-CCA patients and it was discovered that the serum tumor markers which could most efficiently classify the CCA patients from the non-CCA patients were the combination of CA125 and CA242 suggested by the Logistic Regression with C4.5 Decision tree as the classifier, yielding the best performance, with Sensitivity and Specificity being 75.88 % and 86.82%, respectively. In contrast, the classification of CCA patients from BBD patients was best performed by the serum tumor markers CA125 and CA72-4 suggested by C4.5 Decision tree with Logistic Regression or Random Forest as the classifier.

Decolorization of indigo carmine dye using silver nanoparticles synthesized via green method mediated by Leucaena leucocephala: A response surface methodology

Pharini Chaison — 2024-09-25

This study aims to synthesize and characterize silver nanoparticles (AgNPs) from Leucaena leucocephala leaf extract and evaluate their effectiveness in photo-catalytically degrading indigo carmine (IC) dye in an aqueous solution. The synthesized AgNPs were characterized using UV-visible spectrophotometry (UV-Vis), diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. Response surface methodology (RSM) based on central composite design (CCD) was employed to optimize the conditions for the photocatalytic degradation of IC dye under solar light. The results show that 97.52% of the maximum photodegradation of IC dye was achieved using a dye concentration, catalyst volume, and reaction time of 19.7 mgL^-1, 4.47 mL, and 97 min, respectively. RSM results revealed optimal conditions for IC dye degradation under solar irradiation. Moreover, the kinetics study of IC dye showed a good correlation with the pseudo-first order kinetic model.

Correlation between erosion and energy consumption of sandstones

Sarusa Patanapongsonti — 2024-11-07

This study aims at simulating rock erosion by slake durability testing under wet and dry conditions. Phra Wihan sandstone and conglomeratic and bedded sandstones from Phu Phan formation are used as rock specimens. The test parameters are modified from the standard to accelerate the erosion process, where 2,000 drum revolutions are used instead of 200 revolutions for up to 80 test cycles (80 days). Results indicate that fragment roundness and sphericity increase with test cycles. Bedding planes reduce the roundness of bedded sandstone as the fragments become smaller. Phra Wihan sandstone is physically insensitive to water. The water-sensitive and soft Phu Phan sandstone, however, shows notable increases of porosity and reduction of density under both wet and dry conditions. Scrubbing and colliding processes mainly reduce the fragment sizes, under dry condition. Under submerging condition, even though fragment weight is decreased by its buoyancy force, intergranular bonding of the two Phu Phan sandstones is weakened by water penetration, leading to higher percentage of passing materials and lower energy required to disintegrate the rocks than under dry condition. Water insensitive Phra Wihan sandstone erodes more quickly under dry condition than under wet condition. Even though it requires longer period to erode under water submersion, due to buoyancy force, it consumes less energy than those under dry condition to reach the same fragment sizes. Larger sandstone fragments use energy more efficiently to reduce their size than the smaller ones.

Analyzing the students' moral obligation considering their carpooling intentions in Oman

Muhammad Ashraf Javid — 2024-09-04

The rise in private vehicle use causes traffic congestion on the road network and increases the social costs of the trips. Travel demand management (TDM) strategies are deployed to mitigate traffic congestion sustainably as these strategies spread travel needs in space and time by influencing individual travel behavior. Carpooling is a TDM measure used to decrease the use of single occupancy vehicles and promote shared mobility among travelers sharing the same origin-destination and following the same route. This study attempts to identify the correlations between the socioeconomic demographics of travelers and their carpooling potential considering the moral obligations. A questionnaire survey was conducted with the students of the University of Nizwa, Oman, and a total of 156 samples were collected. The results revealed a high interest of respondents in carpooling as a passenger as well as a driver. The respondent's moral obligations are high to carpool for the reduction in traffic congestion, air pollution, and energy consumption. The category analysis showed some differences in interests among different groups. The ordered regression analysis revealed that variables of gender, present travel mode, trip distance, car driving, and carpooling as passengers are significant in determining the moral obligations of the travelers. These results implicate that specific carpooling programs based on specific market segments have the potential for consideration and implementation.

Improving anaerobic digestion of various sludge types through alkaline pretreatment

Watcharapol Wonglertarak — 2024-10-04

This study investigates the impact of alkaline pretreatment on the anaerobic digestion of waste activated sludge (WAS) with varying types and total solids (TS) concentrations. Using NaOH, we optimized pretreatment conditions with a pH of 8.5 and a contact time of 2 hours. Our key findings demonstrate that this pretreatment significantly enhances sludge solubilization, evidenced by a notable increase in soluble chemical oxygen demand (SCOD). Specifically, SCOD increased by 57.5% for domestic wastewater (Plant A) and by 12.1% for industrial wastewater (Plant B) at a 0.5% TS concentration. Higher TS concentrations showed similar trends, with improved solubilization and higher methane production rates. Additionally, pretreatment elevated ammonia nitrogen (NH₃-N) and phosphorus concentrations, with greater releases at higher TS levels. These improvements resulted in enhanced anaerobic digestibility, higher total solids (TS) and volatile solids (VS) destruction, and increased specific methane production. The study underscores the effectiveness of alkaline pretreatment in optimizing anaerobic digestion processes, offering practical implications for wastewater treatment efficiency.

The effects of temperature, moisture content, and cricket frass on gas emissions and survival rates in cricket farming at Honghee Village, Kalasin Province, Thailand

Sopa Cansee — 2024-08-16

Cricket frass accumulation in ponds presents a waste management challenge that can impact cricket farming productivity and quality. This study examines the effects of temperature, moisture content, and cricket frass on emissions of ammonia (NH₃) and carbon dioxide (CO₂) and on cricket survival. This study used a fractional factorial design with treatments repeated three times and was conducted in a temperature-controlled box (0.40 m × 0.60 m × 0.37 m). Freshly prepared and cleaned cricket frass, with adjusted moisture levels, was used. Gas production was monitored daily for 42 days. After replacing the frass with new samples corresponding to the 15 treatments, the environmental impacts on adult crickets were assessed over 7 days, during which the crickets showed a notably high survival rate. The findings indicated that temperature, moisture content, and cricket frass significantly influenced gas emissions and cricket survival rates. A higher moisture content increased the degradation of cricket frass, leading to increased microbial activity and heightened gas production. NH₃ was predominantly detected at the lower positions of the test box. Elevated levels of NH₃ (91.5 ppm) and CO₂ (1395 ppm) were observed at 40 ℃ temperature, 30% w.b. moisture content, and 12.86 kg/m² cricket frass. Despite environmental variations, cricket survival rates remained consistently high, ranging from 95% to 99%, particularly with low moisture content (20% w.b.) and minimal cricket frass accumulation (4.17 kg/m²). This research can assist the environmental management of low-level factors to achieve high cricket productivity. The future application for cricket farms involves managing the environment appropriately, such as cleaning cricket ponds weekly to prevent cricket frass accumulation, controlling the moisture content of food, particularly fresh plant-based food, and using watering methods that do not increase the humidity inside the cricket pond. Additionally, commercial cricket farming could be conducted in controlled temperature rooms.

Assessment of climate change and forest conservation impact on ecologically relevant flows: A case study in Wang River Bain, Thailand

Chutipat Foyhirun — 2024-08-02

Climate change is a major threat to river basins and ecosystems, leading to changes in ecosystems due to rising temperatures, expansion or contraction of specific habitat boundaries, and alterations in the timing of the seasons. This study investigated climate and land use changes to predict future hydrological regime in the Wang River Basin (WRB) and its impact on the ecosystem, focusing on key flow properties such as magnitude, duration, and intensity. The flow properties were studied based on the indicators of hydrologic alteration software and environmental flow components, which were separated into five groups and considered for economic and forest conservation scenarios based on the representative concentration pathway (RCP4.5 and RCP8.5) trajectories. The results showed that future climate change in the WRB will involve severe maximum/minimum temperature increases of 2.09–1.95°C and 4.01–4.05°C for RCP4.5 and RCP8.5 respectively, while the annual rainfall trend will decrease during the 2030s and the 2050s and then increase during the 2070s and the 2090s or a change ranging from -1.96 to 6.10% for RCP4.5 and 1.43 to 6.68% for RCP8.5 from 2030s to 2090s. The projected annual discharges for the combined impacts of climate change and land use change during 2030–2090 indicated that the discharge will tend to decrease in the future, especially in the near future (ranging from -9.75 to -12.32%). Furthermore, there will be an increase in the rise and fall rates (120.24-147.11% and 61.24–62.30%). Consequently, these impacts will eventually affect the livelihoods and ecosystems in this river basin.

Comparison of artificial neural network and response surface methodology in predicting the tensile strength and optimization of 3D printed objects

Pichai Janmanee — 2024-11-07

This study investigates the geometric properties of 3D-printed objects using fused deposition modelling. It focuses on optimising parameters for printing in terms of their significant impact on both the quality and cost of printed objects. To enhance the quality of 3D-printed objects, it is crucial to predict the geometric properties in advance. The development of an artificial neural network model (ANN) is employed to predict the tensile strength properties of polylactic acid material during experiments. The model considers three variables: printing temperatures at three levels (190°C, 210°C, and 230°C), printing speeds at three levels (30 mm/s, 50 mm/s, and 70 mm/s), and material infill density at three levels (40%, 60%, and 80%). Tensile strength testing was conducted, and the predictive performance of ANN models was compared with mathematical models derived from the application of response surface methodology (RSM). The goal was to determine suitable printing conditions. Tensile strength testing revealed that printing temperature, printing speed, and infill density significantly impact tensile strength. The ANN configuration consists of a 3-input layer with 3 neurons, a hidden layer with 14 neurons, and an output layer with 1 neuron, denoted as 3-14-1. The model exhibited a testing decision-making accuracy of 0.938. The average error for the ANN model was 0.307, lower than the average error from the full factorial model, which was 1.392. The optimized printing conditions for maximum tensile strength were found to be a print temperature (X₁) of 230°C, a feed rate (X₂) of 30 mm/sec, and an infill density (X₃) of 80%, resulting in a tensile strength of 43.107 MPa. The mathematical model derived from RSM demonstrated efficacy in predicting and controlling the quality of printed objects, aiming to reduce production costs and enhance efficiency in future 3D printing processes.

Morinda citrifolia L. (Noni) fruits: Optimising extraction kinetics of yield and flavonoids for enhanced antioxidant activity at different temperatures

Tun Faiz Al Hakim Tun Faisal Ismail — 2024-09-23

Morinda citrifolia L., commonly known as ‘Noni’, holds significant potential in pharmaceutical research due to its bioactive constituents. This study aimed to optimise the ultrasound-assisted extraction process for yield and total flavonoid content (TFC) from M. citrifolia fruits at different temperatures (40 °C, 50 °C, and 60 °C). The extraction kinetics were analysed using four models: first-order kinetic, Peleg, power law, and two-site kinetic, determined through goodness-of-fit. Antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. Results showed the peak extraction yield at 40 °C within 90 min, yielding 1.46 ± 0.01 mg/mL, while the peak TFC was at 50 °C within 100 min, yielding 3.43 ± 0.00 mg CE/g db. The two-site kinetic model best described the extraction kinetics based on goodness of fit. The IC₅₀ value for DPPH inhibition was 1883.57 ± 0.02 µg/mL at 50 °C, indicating moderate antioxidant activity compared to ascorbic acid (95.11 ± 0.13 µg/mL). Overall, M. citrifolia fruits provide valuable insights for standardised extraction methods, potentially benefiting therapeutic applications and indirectly reducing operational costs and time for manufacturers.

Mechanical and wear behaviour of boron carbide fillers reinforced Lapox L-12 epoxy composites

Anitha Devi Sonepalli Harigovindan — 2024-07-17

To keep up with the growing demand for composites in fields like medicine, transportation, safety, and athletics, researchers constantly create new composites. These experiments examined the impact of boron carbide filler particles in epoxy by making composites out of Lapox L-12 epoxy with 5, 10, and 15 percent boron carbide fillers using the hand layup technique. The mechanical properties of the prepared composites were measured as per ASTM standards, including hardness, ultimate tensile strength, yield strength, elongation, and flexural strength. Further, wear behavior of prepared composites was evaluated as ASTM G99 standard with varying loads and speeds. Hardness, tensile and flexural strength were increased with a slight decrease in percentage elongation after boron carbide filler particles were added to epoxy Lapox L-12. Lapox L-12 with boron carbide fillers reinforced composites were shown an improvement of 56.4% in hardness, 52.5% in ultimate strength and 25.85% improvements in the flexural strength. The wear behaviour of epoxy and its composites were affected by applied load and speeds. However, Lapox L-12 with boron carbide fillers reinforced composites exhibits higher wear resistance with smooth worn surface morphologies. The improvement in the tensile and wear behavior of L-12 epoxy with _B4C composites can be utilized for several applications like air intake duct and air intake lip of an aircraft.

Parametric study on contribution of combined confining steel and steel fiber to column’s displacement ductility

Slamet Widodo — 2024-06-28

This study examines the contribution of confinement with variations in spacing s_h= (50, 65, and 80) mm and concrete reinforced with steel fiber to displacement ductility. Eight test column specimens (No. 1, 2, 3, 6, 7, 8, 11, and 12) were also reinforced with stirrups according to ACI 318M:19 provisions while four test column specimens (No. 4, 5, 9, and 10) deliberately reinforced with a slightly wider spacing of stirrups with different yield strengths (f_y) (lower than the code requirements). However, the volumetric ratio of the steel fiber was varied, i.e. V_f = 0%, 0.5%, 1%, 1.5%, and 2%. The column was then subjected to a quasi-cyclic and a constant axial load of P_a = 0.121.A_g.f_c'. The test results indicated that all test column specimens could attain the full ductile/fully ductile criteria since m_D>4. When the drift ratio required by ACI 318M-19 is observed, the use of combined confining stirrups and steel fiber works together simultaneously to achieve a drift ratio capacity that exceeds the minimum required target of 3%, meaning that the columns could perform satisfactorily.

Utilization of waste transformer oil for alternative fuel: Design of combustion system model, economic feasibility, and performance test

Lukas Kano Mangalla — 2024-09-04

The utilization of waste transformer oil (WTO) for combustion applications can offer significant potential to generate thermal energy and reduce industrial waste disposal. This study focuses on the development of a burner system designed to utilize WTO as an alternative fuel blended with 30% biodiesel and 70% diesel (B30) to produce thermal energy for various applications in industrial processes. Moreover, the economic feasibility and performance test were explored to provide an overview of the economically designed burner system and inform that WTO blended with B30 is suitable for an environmentally friendly alternative fuel. The development combustor consists of a vertical metal tube cylinder supplied with pressurized air from a blower. Secondary air flow was also provided at the tip of the burner for complete combustion of the fuel. Various test scenarios were conducted to optimize combustion and emission performance. The combustion temperature of the fuel was measured at the tip of the burner, while the emissions gases were recorded at 150 cm above the burner tip. Based on the experimental results, it is shown that the developed burner system can effectively burn the WTO blended B30 to produce thermal with low emissions gases. The maximum combustion temperature reached by the burner is 979°C, achieved with a combustion mixture consisting of 30%:70% WTO/B30 (v/v). The economic feasibility of the developed burner system was very useful and inexpensive to be developed at household or industrial scales and emissions from the combustion process are relatively low, with no significant environmental or health risks. Future studies may explore different fuel blends, system improvements, and broader industrial applications.

Mathematical analysis of scaled-size clinker bed for temperature and pressure drop evaluation

Emmanuel Toluwalope Idowu — 2024-08-08

In order to leverage on existing scaling methodologies, clinker bed was investigated to evaluate its performance for scaled down sizes. Small-sized clinker bed will provide cheaper and faster means of carrying out performance optimization study of clinker cooling process, which has been a research focus in recent years. Heat transfer mathematical equations were adopted to determine the outlet’s temperatures and air pressure drop across the clinker bed, while Buckingham Pi theorem was employed to perform the scaling down of the clinker bed. Findings from the study revealed that for the actual size, predicted air outlet temperature, when compared to the experimental and numerical simulation results from existing literature, produced deviation of –5.46% and +1.65% respectively. For the scaled down-sizes, the air outlet temperature when compared with the actual size of experimental result, yielded deviations of 3.96%, 5.77% and 4.9% because the scaled sizes have 3, 6 and 9 scale factors, respectively. The results further revealed that an increase in mass flow rate of air will improve the heat transfer performance of the clinker bed, but this comes with an increase in pressure drop across the clinker bed heights. Furthermore, an increase in clinker flow rate was observed to be undesirable because the clinker outlet temperature actually being expected to cool down eventually increases, although pressure drop remained unchanged. By adopting a thermal-hydraulic performance factor, maximum percentage deviation between of the actual size and each scaled size was 0.08% which indicates negligible performance deviation. The study therefore reveals that the size of clinker bed can be reduced to enable the development of small-scale prototype, and for numerical simulation to optimize the cooling process, especially when the outlet temperature and air pressure drop are the primary targets of investigation.

Relationship between structural and mechanical properties of polyethylene matrix nanocomposites

Fath Eddine Zakaria Rahmaoui — 2024-07-17

This study examined the impact of incorporating graphene nanoplatelets (GnP) into high-density polyethylene (PE) to create nanocomposites, with and without a compatibiliser. We specifically focused on the impact of structural crystallinity on the mechanical properties of the nanocomposites. These nanocomposites exhibited a much higher Young's modulus compared with pure PE. Specifically, the Young’s modulus increased exponentially with the addition of a compatibiliser and linearly without it. One explanation for this exponential rise in Young's modulus is that the crystal's compacted polymer chain structure improved its stiffness, facilitating effective load transfer. Additionally, a poor distribution of GnP in the nanocomposites with a filler content of 0.5 and 1 wt.%, both with and without a compatibiliser, led to a decreased stress and strain at break. However, at higher filler contents, well-distributed GnP play a key role in enhancing stress and strain at break.

Structural equation modeling of the factors influencing pedestrians’ overpass utilization preference: A case study in Iligan City, Philippines

Joel G. Opon — 2024-07-02

Overpasses are constructed because they allow continuous passage of pedestrians without disturbing the flow of vehicles. However, research from developing countries along with the anecdotal evidence from the study location revealed that generally most pedestrians prefer not using overpasses in crossing roads, rendering them inefficient and causing safety concerns. As such, this paper examines the factors - both observable and latent - influencing pedestrians’ overpass utilization preference. The study was situated in Iligan City, Philippines, wherein four overpasses in the city were investigated by conducting on-site observations and questionnaire surveys. The data collected were analyzed using a combination of multiple linear regression (MLR), exploratory factor analysis (EFA), and structural equation modeling (SEM). On-site pedestrian traffic count revealed that the overpasses in Iligan City are generally ineffective, with only 38.42% average utilization rate. The MLR revealed three observable contributing factors that may affect pedestrian overpass crossing choice: having a driver's license, the overpass width, and the overpass span. EFA and SEM were able to identify safety, convenience, facility condition, and security as the latent factors having a positive direct influence on the preference of pedestrians overpass utilization. These results are instrumental at determining areas of concern relating to overpass design and improvements to increase the utilization rates of the overpass facilities in the city.

Microstructural and mechanical behavior of friction stir welded AZ31-AZ61 magnesium alloys dissimilar joint

Ahmed Kellai — 2024-07-11

In this work, the effect of high tool rotation speed (ω) and forward velocity (V) in dissimilar friction stir welding (FSW) of AZ31-AZ61 magnesium alloys thin plates on microstructural and mechanical properties was studied. The results reveal a continuous dynamic recrystallization and grain refinement in the stir zone (SZ) with formation of precipitates particles Al₈Mn₅ and some undissolved intergranular compounds β-Al₁₂Mg₁₇. Also, the microstructures of both thermo-mechanically affected zones TMAZ_AZ31 and TMAZ_AZ61 consist of elongated restored grains generally coarser than those found in SZ. The heat affected zone (HAZ) exhibits the same grains appearance as those of base metals (BMs). The stir zone displays the highest microhardness with 60 HV and 68 HV for both sides of the weld joint AZ31 and AZ61, respectively. The ultimate tensile strength (UTS) of the welded joint improves, reaching values of 75.77% for AZ31 base materials and 63.55% for AZ61 base materials.

Obesity level prediction using deep learning approach – A comparative analysis

Srinivasa Gupta Nagarajan — 2024-07-25

Obesity, the excessive accumulation of body fat, affected millions globally and was influenced by eating habits, lack of activity, genetics, environmental factors, and emotional strain. It could lead to severe health issues, including insulin resistance, cardiovascular diseases, cancer, sleep apnea, joint problems, and mental health disorders. This study aimed to predict obesity levels using Machine Learning (ML) and Deep Learning (DL) models on a real-life dataset of obesity patients. The dataset comprised several patient health records with 17 different elements related to obesity, classifying obesity levels into seven types. The study evaluated the accuracy of various models before and after applying the Synthetic Minority Over-sampling Technique (SMOTE). Before SMOTE, the TabNet (T) and XG-Boost (XGB) classifiers achieved high accuracies of 96.6% and 96.2%, respectively, outperforming Random Forest (RF) (94.8%), Multi-Layer Perceptron (MLP) (94.5%), Bagging (B) (94.07%), Decision Tree (DT) (93.6%), Support Vector Machine (SVM) (82.5%), K-Nearest Neighbor (KNN) (75.9%), Stochastic Gradient Descent (SGD) (68.6%), AdaBoost (AB) (28.4%), Stacking (S) (16.8%), and G-Boost (GB) (95.5%). After applying SMOTE, GB and XGB showed improved accuracies of 99.3% and 99%, respectively, surpassing RF (97.4%), Bagging (96.28%), DT (96.9%), SVM (90.3%), KNN (85.7%), SGD (67.6%), AB (34.9%), and Stacking (12.3%). Comparatively, the existing methods showed accuracies with GB (97.2%), DT (96.7%), RF (94.8%), SVM (43.4%), and AB (33.1%), while the proposed models exhibited superior performance: GB (99.3%), DT (96.9%), RF (97.4%), SVM (90.2%), AB (34.9%), XGB (99%), TabNet (98.4%), and MLP (97.7%). The proposed models significantly outperformed the existing ones, demonstrating their effectiveness in predicting obesity levels.

A Taguchi fractional factorial design approach to assessing Cattle-Poultry-Hog manure mix ratio influences on biogas yield

Inyeneobong Ekoi Edem — 2024-05-25

Methane production from co-substrate (CS) bio-digestion of cow, poultry and hog manure (CM: PM: HM) can be a potential energy alternative supply. The effect of the co-digestion of these CSs on biogas and methane yield was investigated in this study. Using the Taguchi fractional factorial design (TFFD) method, twenty-eight experiments with varying CSs mix ratios (CMR) were prepared including three experiments made up of the three individual substrates (ISs). Under mesophilic temperature conditions, controlled volatile solid concentration, and a thirty-day hydraulic retention time with all other physicochemical conditions kept unconstrained, the daily cumulative biogas and methane yields were collected and evaluated. Using these, the ultimate methane yields ( were predicted using Richard's kinetic model. The relative of the CSs with those of the ISs was compared to establish the synergistic properties of the CSs. The effects of the CSs interactions were also assessed using a quartic polynomial regression model. Furthermore, the optimal CMR necessary for producing the maximum methane yield was also predicted using the TFFD analysis. The range for the CMRs and ISs was (0.93-1.97) and (0.55-1.31) litres respectively indicating that higher methane yield production is possible with the use of CSs. However, to achieve this, the CMRs have to be carefully chosen. The relative was also found to be higher for all the CMRs further indicating the superiority of co-digesting the substrate rather than mono-digestion. The CSs interactions model showed that the addition of HM and PM produced the best and worst synergistic effects respectively. The TFFD analysis revealed an optimal CMR for CM: PM: HM to be 5:1:5.

Cultivating efficiency in human resource management: The integration of Lean concept and IT solutions for operational enhancement

Chompoonoot Kasemset — 2024-06-17

Improving HRM operations, especially in large enterprises, requires efficient monitoring of issues and documenting individual accomplishments. This study aims to enhance these processes by integrating Lean principles with IT solutions to address inefficiencies, particularly in task recording and achievement tracking, thus advancing real-time data interconnectivity objectives. The study begins with an examination of existing operations, proceeds to analyze the process, and identifies waste while determining the value of activities. Solutions are then proposed using the ECRS technique to improve operational effectiveness. The ECRS technique for lean implementation involves utilizing ‘eliminate’ for non-value-added (NVA) activities, and ‘combine’, ‘rearrange’, and ‘simplify’ for value-added (VA) and necessary but non-value-added (NNVA) activities. After implementing these strategies using Microsoft Planner and Microsoft Power Apps, the time needed for monitoring critical issues is reduced from five days to two per week, along with streamlining the process from seven steps to five. The new application offers updates in real-time and enables staff to independently view their achievement records. Embracing the Lean approach and IT solutions, unnecessary tasks are eliminated, resulting in a reduction of the coordinators' workload.

Influence of prickly pear gum on the physical and mechanical properties of adobe reinforced with palm fiber

Socrates Pedro Muñoz Pérez — 2024-07-11

Throughout history, adobe has been essential to many cultures, but its vulnerability to climate and load-bearing limitations have led to research into new natural materials to improve it. Therefore, the objective of this research was to evaluate the influence of prickly pear gum on the physical and mechanical properties of adobe reinforced with palm fiber. Peruvian standard E.080 was used for adobe preparation under an experimental design, preparing samples with 5, 10, 15 and 20% of prickly pear gum (PPG) to replace the volume of water, reinforcing it with 0.25, 0.5, 1 and 1.5% of palm fiber (PF) by weight of the soil, carrying out tests to determine the physical and mechanical properties of the adobe under study. The results revealed that the optimal dosage was 15% PPG + 0.5% PF, suction and warping decreased by 27% and 3.4% respectively, and absorption increased by 68% compared to the control design. Compression strength in masonry unit, flexural strength in masonry unit, compressive strength in prisms, and diagonal shear strength walls showed significant increases of 24.47, 98, 24.39, and 73.4%, respectively, compared to the control design. It was concluded that the use of PPG and PF provides significant benefits to the physical and mechanical properties of adobe.

Prediction of fatal crashes based on various victim types on national highways passing through urban areas of developing countries

Srinivasa Rao Gandupalli — 2024-06-19

The issue of safety on national roads that traverse urban areas in emerging countries has been a significant cause for concern. Statistical analysis and modelling techniques for road safety evaluation in metropolitan India are still evolving due to inadequate crash data, inventory, and traffic volume data records. This work aims to formulate safety performance functions (SPF) using negative binomial (NB) count data models to pinpoint the variables influencing total fatal crashes and other individual victim types, i.e., pedestrians, motorcyclists, and single vehicles on mid-block sections. Using four years of crash data (2014–2017) from Visakhapatnam City Police, India, the applicability of the current study framework has been established. Besides the geometric design elements, segment length, speed and average daily traffic, this study also focuses on information collected from road safety audits such as the provision of service roads, land use type, median opening, side access, pedestrian crossings, sight clearance to the driver, availability of earthen shoulders, proper signage, and good road markings. The study outcome reveals that road segment length, service road presence, and land use type are significant risk variables associated with fatal crashes in Visakhapatnam City, India. The length of the road segment positively correlated with frequencies of total fatal, pedestrian, motorcycle and single-vehicle fatal crashes. It increased the frequency of fatal crashes on each increment by 103%, 122%, 73% and 98%, respectively. Service roads increase crash frequencies, and road stretches with commercial/mixed land use types attract more crashes. This research emphasizes the essential safety precautions that transportation engineers and planners must implement to establish a more secure environment for all road users.

The effect of a leachate collection ditch on natural attenuation of heavy metal migration from an open dump landfill: An indication from sequential extraction

Krongkaew Mighanetara — 2024-05-24

Open dump landfills are recognised as potential sources of heavy metal (HM) contamination. Their migration to the wider environment is largely controlled by their speciation; and in this study, results from sequential extraction, pH values and organic matter contents in soils around an open dump landfill and sediments in a leachate collection ditch were investigated in order to study the attenuation processes that lead to a decrease in HM mobility. The results revealed that Cu and Zn leached from the landfill were largely retained by sediments in the collection ditch and mostly bound to organic fraction. A simple mass balance suggested that, in comparison to other sources, HM accumulation in soils that resulted from the landfill was relatively low for Cu and relatively high for Zn. The concentrations observed were within safe limits according to the Thai standard for non-residential soil. This study showed that a leachate collection ditch plays an important role in minimising HM migration. Monitoring and further studies on fate and migration pathways of pollutants from open dump landfills, in particular to those underlain by different geologic settings to our study are needed to develop cost-effective measures to prevent/minimise the effect of landfill leachate and ensure that the environment surrounding landfill sites is safe.