Engineering and Applied Science Research

An investigation of pyrolysis kinetics in microwave-assisted conversion of oil palm shell and activated carbon for sustainable bio-oil production

2024-11-13T16:44:19+07:00

This study explores microwave (MW) pyrolysis of oil palm shell (OPS) blended with activated carbon (AC) to produce bio-oil, focusing on the pyrolysis kinetics and the effect of different feedstock ratios. Three OPS mixtures (70:30, 75:25, and 80:20) were analyzed at a constant temperature of 400°C. Gas chromatography-mass spectrometry (GC-MS) revealed that acetic acid, phenol, and other oxygenated compounds were dominant in the resulting bio-oils. Pyrolysis kinetics were modeled using a first-order reaction approach, with rate constants and activation energies determined for each blend. The 75:25 ratio yielded the highest bio-oil content and exhibited the most favorable kinetic performance, showing strong alignment between experimental and simulated data (R² = 0.758). The study also examined the impact of pyrolysis temperatures (400°C, 500°C, and 600°C) at the fixed 75:25 ratio, demonstrating that temperature plays a key role in both enhancing bio-oil yield and altering its chemical composition.

Optimal boosted framework for fatigue cracking prediction in polyethylene terephthalate pavement

2024-11-21T15:00:13+07:00

Depleting natural resources for construction purposes and research needs in the field of civil engineering is becoming a dependable process. To minimize this degradation process several techniques are implemented, one such method is using software approaches in research fields. In the consideration of the former investigation works, the focus point of the works is mainly on Crack Prediction on bitumen pavements. Since the bitumen pavement undergoes repeated loading under wheel loads in static conditions during traffic, and is dynamically loaded during the movement of fast moving vehicles. The strength parameters related to the fatigue limit of the bitumen are not analysed. Hence the fatigue limit of the bitumen should also be analysed. To analyze such conditions, deep learning with standardizing features is implemented to estimate the effective Strength parameters and to forecast the essential outcomes. In this study, the Fatigue Cracking Prediction of the Polymer Modified Bitumen (PMB) of grade 40 in Polyethylene Terephthalate (PET) Pavement is carried out. The Suggested Methodology is termed as Hyena based Curriculum Learning (HbCL). It is implemented in the Accuracy Prediction of Fatigue Cracking behaviour of PET pavement at different temperatures in dynamic and static load conditions. The fitness function in the optimization was triggered initially, to determine the ideal strength parameters of the Polymer Modified Bitumen as well as the PET. The tensile strength of the proposed model is 410 KPa in dynamic loading. The compression strength of the proposed model decreases with an increase in temperature. The rutting depth of the proposed model is between 1.7728mm and 1.6870mm. The Marshall Coefficient value gained was 2.7 KN/mm as the maximum for static loading. A value of 1.77mm in maximum is achieved by fatigue crack depth under dynamical load. The mean fatigue crack prediction accuracy estimated was 96.1%.

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

2024-10-18T11:20:53+07:00

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

2024-10-10T09:31:07+07:00

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.

Evaluation of coal pond ash and quarry dust mix for pavement application

2024-10-30T08:59:34+07:00

The depletion of high-quality natural resources such as soils and aggregates emphasize the necessity of incorporating alternative sustainable materials in road construction. Utilizing these waste materials not only addresses the challenge of their safe disposal but also contributes to sustainable road infrastructure development. The present work examined the potential of coal pond ash (Class F) modified with cementitious material like lime (L) and quarry dust (Q) in the subbase layer of flexible pavements. Through a series of tests including compaction, unconfined compression strength, durability assessment, and repeated load triaxial testing, it was determined that a mixture containing lime modified pond ash (70% P + 10% L) along with quarry dust of 20% exhibited the desired strength and durability characteristics required for subbase material in flexible pavement construction. Also, the proposed mixture demonstrated higher resilient modulus (M_R) than the traditional subbase layer (GSB). Further, the performance of pavement structure with the proposed mix by using KENLAYER analysis showed service life ratio (SLR) values of 1.175 for fatigue and 1.143 for rutting criteria in compared with GSB. From these findings it is suggested that the proposed mix offers a viable and sustainable solution for the road applications.

Mineralogical-based rock abrasivity assessment of siliciclastic and carbonate rocks observed in Mae Moh District, northern Thailand

2024-10-17T09:43:49+07:00

Understanding a target rock's characteristics and tool wear behaviors after cutting that rock significantly leads to appropriate tool selections and reliable tool lifetime prediction for ground excavation or drilling activities in mining and construction industries. Rock abrasivity is defined as the ability of rocks to cause damage to cutting tools. There are several methods for investigating the abrasivity of rocks ranging from micro-scale geotechnical approaches to real-scale in-situ tests. Applying mineralogical analysis to the rock abrasivity assessment methods for the tool wear prediction is lacking in detail, despite its simplicity, effectiveness, and affordability. This study preliminarily tests the abrasivity of four stratigraphic sedimentary units hosted in the Mae Moh Basin, northern Thailand, by investigating a rock abrasivity index (RAI). The method involves microscopic petrographic analysis, equivalent quartz content (EQC) determination, and the uniaxial compressive strength (UCS) tests. The RAI of each representative rock unit is a product of its EQC and UCS. The petrographic results reveal that the rock samples are sandstones and limestones. The sandstones can be divided into two subtypes including sublithic and lithic arenites with the EQC of 90.3% and 43.3%, respectively. The limestones, on the other hand, show the opposite values of below 3%. The UCS results suggest that the strengths of sandstones are higher than limestones. Additionally, the lithic-rich sandstone shows the highest UCS value (92.2 MPa). The calculated RAI of sandstones ranges from 39.9 to 72.5, indicating medium-to-very abrasive materials, whereas the limestones show RAI values of less than 2, indicating non-abrasive rocks. Determination of rock abrasivity using its mechanical and mineralogical properties appears to be a practical method for drilling or excavation strategies.

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

2024-10-09T14:28:09+07:00

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

2024-09-02T16:23:41+07:00

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

2024-08-02T16:48:36+07:00

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.

Evaluation of the Highway Capacity Manual (HCM) and Thailand’s Department of Highways’ approaches to estimating the capacity of a multilane highway segment via the empirical method

2024-10-02T14:25:09+07:00

This study aims to evaluate the methods used by the Thailand Department of Highways (DOH) and the Highway Capacity Manual (HCM 2010 and HCM 2016) for estimating the capacity of an urban multilane highway segment in Thailand, by comparing these estimates with the empirical capacity derived from a speed-flow plot. Field data were collected from a six-lane urban highway segment in Thailand, followed by documentation of the roadway conditions and analysis of vehicle composition. Capacity estimates were calculated using the DOH and HCM methods prior to comparing them to the empirically measured capacity. The results showed that the empirical capacity was 1,619 pc/h/ln. The capacities estimated using the HCM 2010 and HCM 2016 methods were 34.8% and 35.3% greater than the empirically measured capacity, respectively, while the capacity estimated using the DOH method was 14.1% lower than the measured capacity. These findings indicate significant discrepancies in the estimates produced by the three models, when applied to the multilane highways segment. Given that the DOH model has not been updated in over two decades, this study concludes that its accuracy in capacity estimation may be compromised by evolving factors, such as driver behavior, traffic flow characteristics, vehicle types, and vehicle performance. Moreover, the DOH method's omission of variables (including access point density, median type, and terrain type) may further affect its accuracy. Similarly, since HCM 2010 and HCM 2016 are tailored to the United States, using both models to estimate the capacity of the multilane highway segment of interest may lead to errors due to differences in driver behaviors between Thai and American drivers, distinct traffic flow characteristics, the model’s omission of the percentage of motorcycles, and the overestimation of speed at capacity on the highway segment.

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

2024-09-02T11:15:23+07:00

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.

Security enhancement of decentralized healthcare system by transformer blockchain mechanism

2024-10-25T15:33:56+07:00

Medical data plays an essential role in diagnosing diseases and planning therapeutic. However, securing these data is a very critical function in the healthcare system. Some of the traditional Encryption and decryption mechanisms have resulted in a loss of sensitive medical information. In addition, maintaining the confidential score of the medical information is a much more needed and essential task. Considering these cases, the healthcare application was adopted in this present study. Therefore, to enhance security, a novel Transformer Neural Data Encryption Blockchain (TNDEB) has been proposed in this research. The IoMT database was initially collected and trained to detect and eliminate malicious events. Further, the hashing and encryption process has been carried out to secure the data. Moreover, to check the data similarity, the homomorphism function was performed at the verification module, and the verified data was decrypted using the shared private key. The chief contribution of this study is to keep medical information confidential with the support of the holomorphic concept. Additionally, the cryptanalysis was carried out by launching the brute force attack to compute the performance efficiency of the TNDEB model. Subsequently, the validated performance results are compared with existing models. The decrypt and encrypt time achieved by the TNDEB model is 1.260ms and 1.010ms, respectively. In addition, the gained confidential score is 98.8%. Hence, the proposed model is highly suitable for the IMoT application to secure the information at a high confidential rate.

Optimizing mushroom classification through machine learning and hyperparameter tuning

2024-08-20T10:20:50+07:00

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

2024-06-10T10:31:44+07:00

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

2024-06-13T13:30:33+07:00

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

2024-08-09T10:37:49+07:00

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

2024-09-17T11:00:06+07:00

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

2024-07-30T11:55:22+07:00

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

2024-09-16T09:58:55+07:00

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

2024-06-17T15:10:32+07:00

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

2024-05-31T09:32:47+07:00

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

2024-09-05T14:31:56+07:00

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

2024-07-16T17:33:09+07:00

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

2024-06-06T14:27:48+07:00

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

2024-05-03T15:13:55+07:00

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

2024-07-10T10:51:53+07:00

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

2024-06-12T11:10:45+07:00

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

2024-06-24T14:15:12+07:00

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

2024-05-09T10:25:34+07:00

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

2024-06-04T10:34:49+07:00

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.