Performance Test Results Research Articles

Evaluation of biomass‐based cook stoves in Ethiopia: A transition strategy from conventional to modern cook stoves

AbstractPerformance improvement of cookstoves has a vital role in reducing indoor air pollution and deforestation. In this study, biomass‐based cook stoves onsite data survey and experimental approaches were carried out to evaluate the performance of different cook stoves. Based on this feasibility research, it was shown that firewood accounted for 75% of the fuel type usage. The results of several studies and experimental performance testing indicated that the efficiency of cook stoves for 3‐stone, lakech, mirt, gonze, tikikil, and pyrolysis stoves was 10%, 25%, 48%, 50%, and 76%, respectively. Merely 87 out of the total 1986 families with kebeles had improved cookstoves; the remaining households used 3‐stone stove types. According to the study, the pyrolysis stove had the lowest fuel consumption rate and cooking time, while the 3‐stone stove had the greatest fuel consumption rate and cooking time. The improvement stove reduced emissions, and the highest emission reduction stove was the gasifier stove, with a magnitude of 1.229 tons CO2/HH/Year. Among cooking stoves, gasifier stoves have a great advantage in producing energy and biochar.

Synergistic mechanisms of nitrogen configurations in sulfur hosts and their enhancement of electrochemical performance in lithium‑sulfur batteries

Lithium‑sulfur batteries (LSBs) have attracted a lot of attention due to their high theoretical capacity and energy density. However, the cathode material for LSBs is limited by the low conductivity of sulfur and its products, as well as volume fluctuations during charging and discharging, and the shuttle effect of soluble lithium polysulfide. In this work, a cathode sulfur host material Nitrogen-doped porous carbon materials (N-PCM) was synthesized, doped with Pyridine N and Pyrrolic N, using melamine and glycine as nitrogen sources, silicon dioxide as template. The synthesis method characterized by controllable nitrogen content and nitrogen configurations. The results of the electrochemical performance test indicate that the composite N-PCM/S exhibits a higher capacity and enhanced cycling stability. At a rate of 0.1C, N-PCM/S demonstrates an initial discharge capacity of up to 1308 mAh/g. At 2C, the initial discharge capacity is 603 mAh/g, while maintaining a reversible capacity of 543 mAh/g after 400 cycles. The capacity decay rate is only 0.025 % per cycle, showcasing excellent cycle stability. Additionally, the N-PCM/S exhibits excellent electrochemical performance under electrolyte-poor conditions. The results showed that the synergistic effect of different nitrogen configurations significantly enhanced the adsorption and catalytic conversion of polysulfide by sulfur hosts, accelerate the reaction rate of polysulfide.

Synthesis and marine antifouling properties of carbazole amide derivatives with fluorescent properties and their zinc acrylate resins

Fluorescent antifouling is a method that utilizes substances fluorescent repellent effect to prevent organisms attachment and fouling. It is considered one of the directions for developing environmentally friendly marine antifouling materials. The current fluorescent antifouling materials were characterized by issues such as single functionality, unclear antifouling mechanisms, and suboptimal antifouling performance. In this study, three carbazole derivatives containing carbon–carbon double bonds were synthesized by Friedel-Crafts alkylation reaction, and a series of zinc acrylate resins containing carbazole derivative structures were further synthesized through free radical polymerization. Three carbazole derivatives were tested for their fluorescence and their growth inhibition properties against bacteria and algae. The results showed that the three carbazole derivatives not only had high fluorescence intensity, but also had good inhibitory effects on bacteria and algae, with the highest inhibition rate of 81% on algae. The fluorescence properties, algal inhibition properties and anti-algal adhesion properties of the resin were investigated. The results showed that the fluorescence intensity of the resin was enhanced with the increase of carbazole derivative content. The inhibition rate of the resin against algae was as high as 88.5%, and the anti-algal adhesion rate of the resin was improved under light conditions. Mechanistic studies showed that the resin influenced the cell wall, and the fluorescence caused the algae to prioritize photosynthesis rather than attachment and settlement. Self-polishing performance test results showed that the introduction of carbazole derivatives improved the stability of the resin. The results of the real sea antifouling test show that the resin integrates fluorescence, chemical activity and self-polishing, and has excellent antifouling performance. This provides a theoretical basis for the development of environmentally friendly marine antifouling materials.

VR-empowered interior design: Enhancing efficiency and quality through immersive experiences

Traditional interior design methods often struggle to meet the increasingly diverse needs of modern users. As a result, virtual reality (VR) technology has emerged as an innovative solution. This study explores the application of VR technology in interior design (ID), with a focus on enhancing efficiency and quality in the design process. To achieve this, we developed an ID platform based on VR technology and employed Level of Detail (LOD) techniques for 3D model simplification, significantly improving rendering efficiency and effectively reducing rendering times. Performance testing results indicate that the average rendering times decreased from 721.50 ms, 811.20 ms, and 748.10 ms to 335.80 ms, 431.10 ms, and 371.30 ms, respectively, while the frame rates (FPS) increased from 100.80, 85.00, and 93.40 to 107.50, 91.00, and 100.20. These experimental results demonstrate that VR-based design not only accelerates the design process but also significantly enhances the visual quality of interior spaces, providing users with a more immersive experience.

Influence of GNPs@Cu on high-temperature mechanical and thermal properties of laminated MTZ composites

In this study, based on the design concept of nanocarbon-reinforced laminated metal matrix composites, the multiscale toughening effect of the natural laminated structure was applied to the fabrication of MoCu composites, and the laminated 60Mo35Cu2.5Ti2.5Zr composites (MTZ) reinforced with GNPs@Cu (copper-coated graphene) were prepared through the flake powder metallurgy process of ball milling and vacuum hot pressing. The results of microstructural characterisation and performance testing demonstrate that the unique two-dimensional structure of GNPs is highly geometrically compatible with the laminated structure, and the microstructural design of MTZ composites has been successfully realised. Additionally, GNPs can play the roles of fine grain strengthening and dislocation strengthening in the composites, and its regular arrangement in the microstructure can help to improve the load-transferring effect and thus further enhance the mechanical properties of the MTZ composites. Meanwhile, after the chemical plating treatment, the GNPs@Cu is well dispersed in the whole microstructure of the composites and is tightly bonded with the metal matrix, which effectively improves the interfacial bonding and reduces the interfacial thermal resistance as well as the hindrance to the movement of free electrons and phonons. Furthermore, the laminated structure can effectively take advantage of the high thermal conductivity of graphene in the plane direction to improve the thermal conductivity of MTZ composites in the plane direction.

Polycrystalline Diamond Film Growth on Gallium Nitride with Low Boundary Thermal Resistance

As the demand for high-frequency and high-power electronic devices has increased, gallium nitride (GaN), particularly in the context of high-electron mobility transistors (HEMTs), has attracted considerable attention. However, the ‘self-heating effect’ of GaN HEMTs represents a significant limitation regarding both performance and reliability. Diamond, renowned for its exceptional thermal conductivity, represents an optimal material for thermal management in HEMTs. This paper proposes a novel method for directly depositing diamond films onto N-polar GaN (NP-GaN) epitaxial layers. This eliminates the complexities of the traditional diamond growth process and the need for temporary substrate steps. Given the relative lag in the development of N-polar material growth technologies, which are marked by surface roughness issues, and the recognition that the thermal boundary resistance (TBRGaN/diamond) represents a critical factor constraining efficient heat transfer, our study has introduced a series of optimizations to enhance the quality of the diamond nucleation layer while ensuring that the integrity of the GaN buffer layer remains intact. Moreover, chemical mechanical polishing (CMP) technology was employed to effectively reduce the surface roughness of the NP-GaN base, thereby providing a more favorable foundation for diamond growth. The optimization trends observed in the thermal performance test results are encouraging. Integrating diamond films onto highly smooth NP-GaN epitaxial layers demonstrates a reduction in TBRGaN/diamond compared to that of diamond layers deposited onto NP-GaN with higher surface roughness that had undergone no prior process treatment.

A Review of Rheological Properties of Steel Fiber Reinforced Concrete

The rheological properties of steel fiber reinforced concrete have a significant impact on engineering quality, and experimental characterization of the rheological properties of steel fiber reinforced concrete has significant engineering significance and scientific research value. By reviewing relevant literature both domestically and internationally, the article compares and analyzes the construction characteristics and applicable scope of commonly used concrete rheometers, and analyzes the influence of factors such as water cement ratio, mineral admixtures, aggregate properties, steel fiber properties, and additives on the rheological performance test results. The results show that there are significant differences in the test results using different rheometers, and the degree of influence of different factors on the rheological properties of steel fiber reinforced concrete is also different. This can provide reference for the selection of rheological performance testing methods and parameter control of steel fiber reinforced concrete.

Field Performance of Asphalt Mixture Modified with Reactive Isocyanate Based Modifier

The reactive isocyanate-based modifier chemically reacts with asphalt components, overcoming the issues of increased viscosity and phase separation encountered with conventional modified binders. It can be used to modify binders to meet the highest performance grades currently specified by state highway agencies. This project aimed to demonstrate the constructability of an asphalt mixture modified with the reactive isocyanate-based modifier in the field and compare its performance with that of a control mixture. The project involved milling an approximately 5.0-cm (2-in) thick surface layer of two 30.5-m (100-foot) sections with similar foundation support. One section was resurfaced with a reactive isocyanate-modified mixture and the other with a conventional SBS-modified mix. The mixtures have shown no significant difference in field performance and laboratory performance test results. This study has provided insights into the field applicability of reactive isocyanate-based modifiers in asphalt mixtures, facilitating the ongoing efforts to develop durable road surfaces.

Preparation, properties, and characterization of dual-modified tapioca starch and its composite film

Traditional packaging materials easily cause white pollution, developing green biological packaging is highly important for environmental sustainability. In this study, double-modified tapioca starch (DMTS) was prepared and characterized. Further, clove essential oil (Ceo) at concentrations of 0.5 %/0.75 %/1.0 %/1.25 % (wt%) was loaded into the DMTS film matrix to develop an applicable active packaging material. XRD analysis and FT-IR results revealed that esterified starch was successfully prepared, the DM/CS/Ceo films had a dense intermolecular network, and the Ceo was successfully incorporated into the polymer matrix. The performance test results demonstrate well-performing mechanical, hydrophobic, and antioxidant properties of Ceo series composite films. Specifically, the EAB of the 1.25 % Ceo film increased by 10.7 %, the water contact angle increased by 18.89°, and the DPPH free radical clearance increased by 12.79 times compared to that of the DM film. In addition, the inhibition rates of the 1.25 % Ceo film against Escherichia coli and Staphylococcus aureus reached 86.51 % and 86.84 %, respectively. These results indicate that Ceo films have tremendous potential application value in prolonging food storage life.

On the Issue of Constructing Spatial Isolines for Irregular Monitoring Networks

The article examines spatial isolines construction based on data on an irregular grid. In particular, a possible solution to the problem of contour breaks is explored. Measurements of the magnetic field parameters taken from variation stations are used as data. The paper presents a description of the algorithm for constructing isolines and describes the software system that implements this algorithm. The results of system performance testing are given in the last chapter.

Intelligent alarm system for river embankment seepage based on BILSTM

Currently, the alarm functions of existing levee seepage monitoring systems are limited to single-parameter monitoring and lack rate-of-change alarms and correlation alarms. This can lead to false alarms, missed alarms, equipment failures, or unnecessary downtime. To enhance the intelligence of levee safety monitoring and seepage alarms, a levee seepage intelligent alarm system based on a Bidirectional Long Short-Term Memory (BILSTM) network model was designed and implemented. Firstly, data cleaning and preprocessing are carried out on the engineering safety monitoring operation data to reduce the influence of dirty data such as outliers and repetitive values on the accuracy of alarms. Secondly, for the correlation between the piezometric tube water levels of the levee and the Yangtze River water levels, a correlation analysis based on Mutual Information (MI) theory was conducted to minimize the effect of piezometric tube water level change delays on correlation. Finally, the BILSTM model was used to predict trends in these potentially abnormal data intervals. Based on engineering application requirements, alarm thresholds were established, and a multi-level alarm module was developed. Field operation test results show that the proposed method can accurately predict the piezometric tube water levels of levees, achieving intelligent alarms within the engineering safety monitoring system.

Z-scheme heterojunction TNCoPc/BiOBr nanomicrospheres for efficient photodegradation of tetracycline and rhodamine B: Degradation performance, intrinsic mechanism and degradation pathway studies

The natural ecosystem has been significantly jeopardized due to the misuse of organic dyes and antibiotics. To treat organic wastewater safely and efficiently, this study synthesized a binary composite photocatalyst TNCoPc/BiOBr, using a solvothermal method that involved loading cobalt tetranitro phthalocyanine onto BiOBr. The results of the catalytic performance tests indicated that the composites exhibited the capacity to degrade rhodamine B and tetracycline hydrochloride by 97.75 % and 78.37 %, respectively. Moreover, the composite exhibited good cyclic stability. Subsequent analytical characterization confirmed the formation of a Z-scheme heterojunction, resulting in a synergistic effect. This Z-scheme heterojunction facilitated the capacity of photocatalyst to achieve enhanced light absorption, augmented photogenerated carrier separation efficiency, and augmented redox capacity. Additionally, theoretical calculations were employed to further elucidate the catalytic mechanism and synergistic effects. The results demonstrate that the Co-N4 sites are the active center of the TNCoPc and verify the contribution of nitro substitution to the photogenerated electron transfer mechanism on TNCoPc. Furthermore, a systematic degradation pathway was predicted and deduced based on Fukui indices and liquid chromatography-mass spectrometry data. This study presents a paradigm for the application of composite photocatalysts containing substituted phthalocyanines in the degradation of organic wastewater.

Tribological properties of graphene oxide reinforced aramid paper-based composites

Self-lubricating paper-based composites can provide technological solutions such as low friction and extended service life for the aerospace airframe kinematic mechanical components. To improve the tribological properties of aramid short fibers, this study chemically combined graphene oxide (GO) with aramid nanofibers (ANF) through intermolecular forces, creating a self-lubricating GO-reinforced aramid paper-based composite GO/ANF. Mechanical performance tests have shown that the introduction of GO can significantly improve the fracture strength, Young's modulus, and toughness of paper-based composites. The frictional performance test results show that compared with ANF, the GO/ANF paper-based composites can maintain the lowest coefficient of friction (COF) and wear under high load and high sliding rate conditions. When the amount of GO added is 1 wt%, the COF and volume wear rate of GO/ANF paper-based composites are reduced by 23 % and 89 %, respectively. Mechanism analysis indicates that synergistic effects and friction transfer films are important factors contributing to the excellent performance of paper-based composites. This GO/ANF paper-based composite has good application prospects as a good anti-wear liner material in self-lubricating sliding bearing.

RANCANG BANGUN TRANSMIS MESIN PERONTOK 3600 RPM BERBASIS MOTOR BENSIN

A rice threshing machine is the process of separating rice from its stems, so that reducing rice agricultural yields is very strategic in supporting rice production. Modification of the tool which previously used a slamming system, resulted in the yield of grain containing quite high levels of grain. The aim of this research is to design the transmission rotation to make the belt pulley and shaft more effective. The rice threshing machine transmission system consists of a pulley and belt with various belt sizes. The appearance of the pulley for calculations is adjusted to a pulley size of 10 inches = 25.4cm. Then the belt that connects the 10 inch/25.4cm pulley and the 9.74cm A58 belt is the belt that connects the pulley and the shaft. Based on the results of transmission performance testing with power and planning moment of 5.8164 kW and pulley planning moment of 1573.65 kg.mm from type A, the calculation of driver pulley rotation = 3 inches (d1) and motor rotation = 3600 rpm (n1) can be used rpm of the drive pulley when it is not loaded and when working, namely the rpm of the drive pulley when it is not loaded is 1080 rpm. Furthermore, the pulley rpm when working is 9.75\ rpm\ and\ The design power of the shaft is 4.92\ for the shear stress that occurs on the shaft of 0.838 kg/mm which is smaller than the allowable shear stress with a value of 5.16 kg/mm. so that the power and moment of planning the shaft with a diameter that can be used safely.

Mechanical behavior and microscopic damage mechanism of hybrid fiber-reinforced geopolymer concrete at elevated temperature

Geopolymer concrete (GPC) that is prepared from eco-friendly materials exhibits much more excellent resistance on high temperature compared with ordinary Portland cement concrete. In this study, hybrid fibers containing varying proportions of steel fiber (0.5%–2.0 %) and polyvinyl alcohol (PVA) fiber (0.2%–0.8 %) were incorporated in GPC. The hybrid fiber-reinforced geopolymer concrete (HFRGC) was subjected to temperatures ranging from 200 °C to 800 °C. The physical properties tests, mechanical properties tests, and microstructure tests of HFRGC were carried out at elevated temperatures, while the environmental impact and cost-effectiveness of HFRGC were assessed. The results of physical properties tests showed that the appearance and mass loss of the HFRGC were mainly affected by temperature, while hybrid fibers had a negligible effect on both. The appearance of HFRGC gradually transformed from gray to brick red with increasing temperature, and the mass loss of HFRGC at 800 °C was as high as 9.4 %. The mechanical performance test results indicated that the mechanical strength of HFRGC increased at 200 °C and then decreased with elevated temperature. At 200 °C, the compressive strength, splitting tensile strength, and flexural strength of HFRGC containing 1.5 % steel fibers and 0.6 % PVA fibers were respectively increased by 13.1 %, 14.7 %, and 4.4 % as compared with ambient conditions. The microstructure test results showed that further geopolymerization at 200 °C promoted the densification of the matrix. The matrix was damaged at higher temperatures violently while the porosity of HFRGC was dramatically increased from 13.35 % at 25 °C to 27.83 % at 800 °C. Based on the thermal behavior, environmental impact, and cost-effectiveness of HFRGC, a reference for future research in the fire prevention of GPC was provided.

High-value care modeling: Evaluating cost conscious and potentially wasteful behaviors.

42 Background: Value-based care is key to decreasing waste, addressing increasing healthcare costs, and minimizing patient financial toxicity - especially in the treatment of high-cost diagnoses such as cancer. Medical student exposure to role-modeling of high-value care (HVC) behaviors may help shape professional identity formation and have long-term effects on future practices. Our study aimed to investigate the frequency and characteristics of faculty role-modeling of HVC in medical student core clinical rotations. Methods: A cross-sectional survey study was performed with third- and fourth-year medical students on clinical rotations at 11 U.S. medical schools. The survey assessed thirteen variables associated with cost conscious role-modeling behaviors or potentially wasteful role-modeling behaviors, as well as questions characterizing the rotation such behaviors were observed on, demographic information, and organizational culture around HVC. Results: Cost-conscious role-modeling behaviors were observed “sometimes” or “often” between 52.9-70.5% of the time across all clinical rotations, with the exception of observing a student or resident being praised for ordering a cost-effective diagnostic work-up (seen only 25.7% of the time). Potentially wasteful role modeling behaviors were observed “sometimes” or “often” 5%-14.3% of the time, except simultaneously ordering numerous tests before seeing results of initial screening tests (45.1%) and repeating tests rather than attempting to obtain recently performed test results (42.9%). HVC was most often observed on internal medicine rotations (58.3%) and least frequently on surgery rotations (34.5%). Attendings were significantly more likely to model HVC compared to residents/fellows in 5/7 domains. Organizational culture correlated with frequency of HVC behavior observed. Conclusions: HVC role-modeling behaviors, as observed by medical students, are variable across clinical rotations. HVC practices are essential not only within oncology, but across all medical specialties; future studies should strive to identify factors which promote or inhibit HVC modeling and understand differences between HVC education in undergraduate medical curriculum.

Performance analysis of selected database management systems

The article presents the results of performance tests of database management systems. In order to conduct the tests, an application running in Java environment and using an ORM tool such as Hibernate for communication with the database was used. The tests were carried out for test scenarios such as CRUD operations, join queries, aggregate functions, and filter conditions in queries. The DBMSes used for testing were MySQL, PostgreSQL and H2. Performance analysis looked at the execution time of operations, RAM usage and CPU load. Additionally, tests were carried out for different sizes of user groups using the application. PostgreSQL proved to be the best choice for complex operations.

Classification of Traffic Violations Using the Naïve Bayes Algorithm at Padang City Police

Traffic violations have been increasing each year. According to data from the Padang City Police from 2018 to 2023, there were 128,913 traffic violation cases. This is not a small number, and it is time for the police to start utilizing machine learning (ML) technology to evaluate traffic violation cases, as ML can identify hidden patterns or information that cannot be detected manually by conventional statistics or by traffic officers. This research aims to classify traffic violations using the Naïve Bayes algorithm at the Padang City Police by conducting evaluations and comparisons using different dataset ratios. The best algorithm obtained from the comparison will then be analyzed, and the research findings are expected to serve as a reference for the relevant authorities. This research is quantitative in nature, using an experimental method. The data sources or information were obtained from traffic ticket documentation at the Padang City Police and questionnaires distributed to traffic officers of the Padang City Police. The research results show that the Naïve Bayes (NB) algorithm can be used to classify traffic violations at the Padang City Police. The performance test results of the Naïve Bayes (NB) algorithm using all comparison algorithms with different training and testing dataset ratios resulted in 100% accuracy. However, during cross-validation, the Naïve Bayes algorithm achieved the highest accuracy only with training and testing dataset ratios of 80%:20% and 90%:10%. This is due to the large dataset size in this research, which is more than 100,000 entries. The evaluation results of the Naïve Bayes algorithm show that the best model is achieved with the Naïve Bayes algorithm using an 80% training and 20% testing dataset split. Although the performance is similarly high with a 90%:10% training and testing ratio, the researcher chose the 80%:20% training and testing ratio as the best algorithm for reasons of efficiency during training. The argument is that even with just 80%, it is able to predict/classify 20%, which is more efficient than training 90% to predict/classify 10%. Another finding from this implementation is that with a large dataset of 100,000 entries or more, high and stable performance can be achieved, so this research also suggests that to achieve good results from traffic violation classification, the dataset should be above 100,000 entries.

Analysis and Evaluation of Load-Carrying Capacity of CFRP-Reinforced Steel Structures.

Carbon Fiber Reinforced Polymer (CFRP) can be used to reinforce steel structures depending on its high strength and lightweight resistance. To analyze and evaluate the load-carrying capacity of CFRP-reinforced steel structures. This study uses the Finite Element Analysis (FEA) and the experimental tests combined to investigate the influence that the reinforcement patterns and the relevant parameters have on the load-carrying capacity. We made specimens with different reinforcement patterns. Take the steel beam specimen with full reinforcement as an example. Compared with the load-carrying capacity of the steel beam reinforced by two-layer CFRP cloth, that respectively increases by 5.16% and 11.1% when the number of the CFRP cloth increases to four and six, respectively. Based on a specimen set consisting of CFRP-reinforced steel structures under different reinforcement patterns, the random forest algorithm is used to develop an evaluation model for the load carrying. The performance test results show that the MAE (Mean Absolute Error) of the evaluation model can reach 0.12 and the RMSE (Root Mean Square Error) is 0.25, presenting a good prediction accuracy, which lays a solid foundation for the research on the CFRP-based reinforcement technology and process.

Helmet Net: An Improved YOLOv8 Algorithm for Helmet Wearing Detection

It is of profound significance to detect whether cyclists wear helmets to protect their personal safety and maintain road traffic safety. Due to the limitations of space, distance and cyclist movement, it is challenging to detect helmet-wearing accurately and quickly. In view of this, a novel You Only Look Once (YOLOv8) algorithm for helmet-wearing detection is suggested in this paper. Firstly, YOLOv8n with the best performance test results is selected as the baseline model from several advanced object detection algorithms. Secondly, improvement measures are taken for YOLOv8n. The squeeze-and-excitation networks (SENet) is integrated at the C2f of the neck to improve the network representation ability. Part of conv modules in the backbone is replaced with the lightweight convolution (LConv) to improve the computational efficiency and the generalization ability of the model. The loss function is changed with the Wise-IoU (WIoU), to enhance the overall performance of the model. Additionally, the reasoning method is replaced by the slicing aided hyper inference (SAHI), which aims to lower the rate of missed detections for smaller objects and strengthen the accuracy of their detection. Through the above improvement methods, a new helmet-wearing detection algorithm is formed, called helmet net. Furthermore, in comparison to the YOLOv8n, the proposed algorism demonstrated an increase in precision, recall, and mean average precision (mAP) by 5, 7.3, and 6.4%, respectively, for helmet-wearing detection. At the same time, the speed reaches 111.1 fps, which can contribute to the real-time detection of helmet-wearing. After adding SAHI, the detection results show that the model can detect more small objects, which further enhances the competence of model for helmet-wearing detection.