bluuebunny/crossref_metadata_2025 huggingface dataset:
Segment-compensated Bandgap Reference Generator with Low-temperature Drift
Authors: Yan Yu , Huang Shengming
Published: July 2024

In this paper, a segment-compensated low-temperature-drift bandgap reference generator is proposed and designed to get the high-order nonlinear temperature characteristics for the bandgap reference circuit. Based on the Nuvoton 0.35 μm BCD process, the circuit is simulated and analyzed. The result is that a temperature coefficient of 1.12 ppm/℃ over the range of -40℃ to 125℃ is obtained, which is much lower than the 6.88 ppm/℃ before compensation. It is demonstrated that the power supply rejection ratio is 141.3 dB at 1, 000 HZ, low-frequency open-loop gain is 75 dB, and a phase margin is 57°.
Research on the welding process of Q355ND thick plate with narrow gap double wire submerged arc welding
Authors: Li Su , Zhang Wei , Zhang Yupeng , Han Shanguo , Wang Haiyan , Xin Yanggui
Published: July 2024

Aiming at the problems of low welding efficiency and unstable quality of thick plates of marine equipment in offshore deep-water areas represented by offshore wind power, the high-efficiency welding process of narrow-gap double-wire submerged arc welding of 30 mm thick Q355ND low alloy high-strength steel plate was developed by selecting the suitable welding material and welding process parameters. The results show that the welded joint has a beautiful appearance, well-fused sides, and no defects. The structure of the heat-affected zone of the joint is mainly composed of pro eutectoid ferrite, acicular ferrite, bainite, and a small amount of pearlite. The center of the seam is composed of a large amount of massive ferrite and a small amount of bainite. The average tensile strength of the joint reaches 536.5 Mpa, and the average impact energy of the weld center at -20°C reaches 48.4 J. The average impact energy of the heat-affected zone reaches 164 J. All physical and chemical performance tests meet the standard requirements. The development of welding processes has important practical significance for improving production efficiency and product quality. It will be widely used to construct offshore wind power towers, offshore platform jackets, and other offshore deep-water engineering equipment.
Design of intelligent pipeline detection and cleaning robot
Authors: Peng Fang , Su Zihao , Lei Ming , Sun Qiang , Chen Yida
Published: July 2024

This design focuses on the field of intelligent pipeline cleaning, and proposes a design scheme for an intelligent household multi-functional pipeline cleaning robot that can realize multiple functions such as damage monitoring, cleaning and repair for different pipeline structures and internal multi-physical environments. It is equipped with integrated systems such as visual recognition, pressure sensors, robotic arms, underwater gimbals, and telescopic devices, and has functions such as pipeline cleaning, turbine pushing, crawler crawling, and damage monitoring.
Testing technology and evaluation of substructure of urban viaduct in service
Authors: Liu Dongxin , Zhang Li , Wang Peimao , Tang Wenbo , Ma Yu , Chen Zhengyang
Published: July 2024

This paper mainly focuses on the test and inspection work of the viaduct substructure. With the acceleration of the urbanization process, the viaduct is an important part of urban traffic, and its safety and stability to ensure people’s travel safety and the normal operation of the city is very important. As the basic structure supporting the bridge body, the safety of the substructure of the viaduct is directly related to the safety of the whole bridge. Therefore, it is very important to inspect the substructure of the viaduct.
Analysis of the influence of winding phase shift on the comprehensive performance of multi-mode operation characteristics of dual-winding permanent magnet synchronous motor
Authors: Shi Qiaoning , Zhang Yufeng
Published: July 2024

The objective of this study is to investigate the electromagnetic properties of dual-winding permanent magnet synchronous motors with various winding phase shift angles, both under normal and fault-tolerant operating conditions. Initially, an analysis of the phase shift angle for the dual-winding motor windings is conducted, followed by the design of three distinct configurations with different phase shift angles for a 12-slot 10-pole motor. Subsequently, in the second section, a finite element model is developed to represent both healthy and faulty states of the 12-slot 10-pole dual-winding permanent magnet synchronous motor with varying phase shift angles. The third part of the study involves comparing and analysing the electromagnetic characteristics of the motor under different winding phase shift angles in healthy conditions. The fourth section delves into the comparison and analysis of the electromagnetic properties of motor faults across different winding phase shift angles. Finally, conclusions are drawn based on the analysis and summary of the electromagnetic characteristics of motor faults and health conditions across various winding phase shift angles.
A novel adaptive gramian angle field based intelligent fault diagnosis for motor rolling bearings
Authors: Yu Shubo , Liu Zhansheng , Wang Saibo , Zhang Gaorong
Published: July 2024

The Gramian Angle Field (GAF) can encode one-dimensional vibration signals into two-dimensional feature maps containing time correlation information. However, the feature representation ability of traditional GAF-encoded images is limited, making it challenging to further improve fault diagnosis accuracy. To address these issues, an AGAF-CNN intelligent fault diagnosis method is proposed in this paper. In addition to traditional GAF encoding, an adaptive adjustment parameter is introduced that automatically determines its value based on the dynamic distribution characteristics of the input data. This ensures that the resulting feature map after two-dimensional encoding contains optimal fault discriminant features. By leveraging CNN’s capability to process image data, the proposed method extracts deep-level feature representations from the vibration signal feature map and performs accurate diagnosis. The approach is validated using a rolling bearing dataset from Case Western Reserve University in the United States, and superior diagnostic accuracy is demonstrated compared to other vibration signal coding methods combined with CNN-based fault diagnosis methods. The theoretical and practical advantages of AGAF feature coding are explained comprehensively.
Research on microcracks detection of metal plate based on nonlinear ultrasound
Authors: Zhan Xianglin , Liu Lian
Published: July 2024

In recent years, phased array ultrasonic non-destructive testing technology has been increasingly applied in the field of non-destructive testing. However, current phased array ultrasonic testing is based on traditional linear ultrasound and is not sensitive to defects such as microcracks in materials. This article proposes a nonlinear ultrasonic phased array detection technology—fundamental amplitude difference. Nonlinear components are obtained by subtracting the transmission of even and odd elements from the transmission of all elements in a phased array. First, to improve the detection effect, MATLAB software is used to simulate and study probes with different parameters. Under the premise of meeting the probe design standards, the various parameters of the probes are determined. Then, an experimental model was established using the finite element tool Abaqus. The relationship between microcracks of different lengths and nonlinear components was calculated by constructing multiple microcrack damage models. The final simulation results show that as the size of microcracks increases, the corresponding nonlinear components also gradually increase, which can more accurately detect nonlinear components and improve detection accuracy.
Research on Simulation and Power Regulation Control Strategy of Fengning Variable-Speed Pumped Storage Unit
Authors: Bai Changyu , Cai Weijiang , Zhai Jinnan , Yu Shuang
Published: July 2024

Variable-speed pumped storage unit demonstrates rapid power response and flexible adjustment of unit speed, significantly enhancing unit operational efficiency and the power system’s stability. This paper focuses on simulating the control strategy of the Fengning variable-speed pumped storage unit. First, the water pump/turbine and motor models are established based on the relevant parameters of the Fengning variable-speed pumped storage unit. Second, according to the distinct responsibilities of the governor and the excitation system, the control strategies of the unit in the power priority mode and speed priority mode are designed. Finally, we compare and analyze the power response characteristics of a single-machine infinite bus system under various operating conditions and control strategies. We also summarize the applicable scope and existing problems under different operating conditions.
A control strategy for peak clipping and valley filling based on DC microgrid
Authors: Wei Qing , Shao Guangyi , Wu Hao , Wu Qian , Zhang Yanchi
Published: July 2024

In this paper, the peak clipping and valley filling control strategy for DC microgrid is proposed. The purpose of the proposed control strategy is to make the power system run more smoothly while reducing the cost of electricity. The working mode of the DC microgrid is determined by the peak-valley time of the electricity cost. By distinguishing different periods of time, the charging and discharging of the battery are controlled, and the difference between the peak and valley electricity prices is earned for the users. The maximum power was extracted from photovoltaic panels by P&O (Perturb and Observe) MPPT algorithm, and SPWM technology based on droop control strategy was adopted. The system is simulated in matlab/simulink environment, and the feasibility of the control strategy is verified.
Development and Application of Substation Grounding Grid Topology Detection and Recognition System
Authors: Ji Wangwei , Lin Yi , Li Guocheng
Published: July 2024

To solve the problem of substation grounding grid faults difficult to diagnose in the case of non-power non-excavation, based on the inductive apparent magnetic resistance method developed a set of grounding grid topology detection and identification systems, to achieve non-destructive detection and real-time imaging of the grounding grid location, structure, breakpoints, and other information to identify and rebuild the topology of the grounding grid. The paper introduces the system design and practical experiments and applications in a substation in Guangzhou City, the system has achieved good application results, reaching the level of engineering prototype, the development of the system device has a good practical significance, and has a broad application prospect.
Analysis and Optimization of Lightning Protection Level Against Backflash for 220 kV Transmission Lines
Authors: Ma Hui , Sun Fengwei , Wang Dazhong , Fan Bo , Shi Sinan
Published: July 2024

Lightning strikes are a major cause of insulator flashover and line tripping; hence, improving line lightning resistance is essential. This article establishes a 220 kV transmission line model in PSCAD/EMTDC and examines the effect of alternative grounding resistance and phase arrester configurations on lightning resistance levels. The analytical findings demonstrate that the transmission line’s lightning resistance level is inversely connected with its ground resistance. When ground resistance cannot be lowered, lightning resistance can be improved by adding a lightning arrester. The lightning resistance level of each arrester arrangement varies depending on the ground resistance circumstances. An appropriate configuration policy must be picked depending on the site characteristics. The study results in this research give a specific reference for lightning protection transformation of 220 kV transmission lines.
Research on Metal Corrosion Behaviour of Indirect Air-cooled Circulating Water System
Authors: Li Yongli , Wang Xijun , Tan Yu , Zhang Xiuli , Wei Junjie , Zhang Hongjiang , Xing Chengxia , Hu Yuanxiang , Wang Rui , Zhang Shenghan
Published: July 2024

The indirect air cooling system of an air-cooled power plant consists of a surface condenser and an aluminum radiator. The radiator is usually made of 1050A pure aluminum, and the circulating water pipe connecting the radiator is made of Q235B carbon steel. This article simulates and controls typical water quality parameters such as dissolved oxygen and pH value in indirect air cooling systems using a self-designed simulation device, and studies the influence of various water quality parameters on material corrosion behavior in intercooled circulating water systems when aluminum and carbon steel coexist. The results indicate that factors such as dissolved oxygen, conductivity, pH value, temperature, and redox potential can all affect the corrosion rate of carbon steel and aluminum materials; The increase in temperature and dissolved oxygen leads to an increase in corrosion rate; The main way carbon steel corrodes the system is by consuming dissolved oxygen; The corrosion behaviour in the water circuit will lead to an overall decrease in pH value. In the presence of multiple metals, the influence of iron ions in the solution significantly increases the corrosion rate of aluminum.
Testing Deicing Force of Fire Preventive Clothing by Introducing Universal Testing Machine Based on Modified Aided Equipment
Authors: Yanfei Chen , Ning Wang , Xiyu Chen , Jianjun Xia
Published: July 2024

To determine the deicing force of forest fire preventive clothing, modified aided equipment for a universal testing machine was designed. Firstly, the cold situations were analyzed in five clothing climate zones of China. Secondly, the traditional equipment for push-pull force gauges was redesigned for higher accuracy. Thirdly, the outer layer of forest fire preventive clothing was coated by a hydrophobic silicone rubber coating. Finally, the deicing force was tested by a introducing universal testing machine. The results showed that the data of deicing force in different tests had good consistency by introducing a Universal Testing Machine on modified aided equipment.
Research on the Design and Temperature Rise Performance of Megawatt-level Ultra-high Current Charging Connection Components for Electric Vehicles
Authors: Zou Zhiping , Wang Jiandong , Pang Yuefeng , Ding Jiafeng , Lu Zizhao , Zhang Kaiyu , Wan Sha
Published: July 2024

With the clear trend of low-carbon transformation of transportation, the electrification process of heavy-duty vehicles has created an urgent need for high-power charging technology. In this paper, a charging connection module with megawatt-level charging power is designed based on the ChaoJi charging interface, and the compatibility and safety of the module are enhanced by adding mechanical code locks and electric locks. The temperature rise test and heat transfer failure test under 1200-1700 A current are also carried out on the charging connection assembly, and the results show that the charging connection assembly can meet the temperature rise performance requirements of 1500 A current charging. At the same time, it also ensures stable and safe operation without a cooling device for 40 s when the heat transfer fails.
Effect of Different Skew Angle on Tensile Fracture Behavior of SiC Fiber Monofilament
Authors: Zhang Xingjian , Fan Jinjuan , Liu Changkui , Ye Jinfa , Peng Ruiqi
Published: July 2024

In fiber reinforced composites (FRP), silicon carbide fiber is indispensable. Its mechanical properties determine the performance of ceramic matrix composites. Therefore, the tensile and fracture behavior of silicon carbide fiber monofilaments should be studied in depth. In order to make the test results of fiber properties more accurate, this paper takes SiC fiber monofilament as the research object, carries out tensile tests at different deflection angles, and carries out WEIBULL statistical analysis and comparison of the data. The microscopic morphology of the tensile fracture of each single fiber was observed by SEM, and the change rule of the mechanical properties and fracture behavior of the fiber with the deflection angle was summarized, and whether the slight deflection affected the test results was explored. The results showed that: (1) The mechanical properties of SiC fiber monofilament decreased gradually with the increase of deflection angle, and the extent of decline gradually increased. (2) With the increase of deflection angle, the proportion of stepped fracture gradually increases, and that of flat fracture gradually decreases.
Numerical simulation of mechanical properties of composite high-pressure vessel for space application
Authors: Gu Sendong , Zhao Jipeng , Ma Yanlong , Yang Wenbo , Yu Bin , Wang Tian
Published: July 2024

A composite high-pressure vessel reinforced with T1000 carbon fiber and featuring an ultra-thin titanium lining for space applications is examined. Using the laminated plate theory for composite materials and the elastic-plastic theory for isotropic materials, a three-dimensional finite element model is developed. The pressure test results confirm the correctness of the finite element model. Under various internal pressure circumstances, the displacement and strain distribution of the metal liner and the laminated composite are compared and analyzed. It is shown that the composite vessel primarily deforms along the axial direction when the internal pressure is greater than the working pressure of the vessel. Only elastic deformation is present in the composite layer, but both plastic and elastic deformation are present in the ultra-thin titanium liner.
Mechanical mechanism of shear cavitating water jet dissociation of flake graphite
Authors: Dong Xing , Jiang Yun , Guo Chenhao
Published: July 2024

To obtain the mechanical mechanism of shear-type cavitation water jet dissociating flake graphite to improve the grinding technology of flake graphite, the motion state of flake graphite particles in shear-type cavitation water jet, the micro-jet impact process, the high-pressure elastic potential energy pressure release process, and the water wedge stretching process have been analyzed using the theory of hydraulic transport of liquid-solid two-phase, the theory of jets, the cavitation primordial principle, the principle of capacity conversion, and the water wedge action. The primary mechanical mechanism of shear cavitation water jet dissociation of flake graphite is collision friction effect, micro-jet impact, pressure release, and water wedge stretching effect, under these four kinds of loads individually or jointly, to achieve the purpose of removing the surface of flake graphite particles of the veinstone minerals to realize the dissociation of flake graphite. Moreover, the collision friction, pressure release, and water wedge stretching effects destroy the material under tensile stress to remove the veinstone minerals, and the micro-jet impact effect is the destruction of the material under compressive stress to remove the veinstone minerals.
Field Natural Experimental Study of Ice Growth Characteristics of Split Conductor and Single Conductor on Hybrid Freezing Icing
Authors: Wang Yuelong , Wang Yanwei , Zhang Shuwei , Zhang Zhijin , Wang Linghao
Published: July 2024

Transmission line icing seriously endangers the safe operation of transmission lines. At present, most of the research on transmission line icing is based on numerical simulation, and the growth law of transmission line ice in a natural environment has not been explored and studied. In this paper, natural ice-covering experiments are carried out in the Xuefeng Mountain Field (Natural) Ice Covering Test Base of Chongqing University, and single conductor, three-split, and four-split conductor ice-covering change rules in the mixed rime ice environment are explored. Test results found that the wind direction has a greater impact on the ice, and the windward side of the conductor ice is much larger than the leeward side. The downwind side of the ice of both single conductor and split conductor is smaller than the upwind side. The weight of ice on the split conductor line on the downwind side is about 86% of that on the upwind side. The results can provide a reference for the design of external insulation of UHV DC transmission lines.
Experimental and Engineering Simulation of Loss Characteristics of Silicon Steel Wafers Based on Levenberg-Marquardt Optimization Algorithm
Authors: Lv Benqing , Ning Yinhang , Huang Zhihao , Fu Longlong , Xu Shuai
Published: July 2024

The loss characteristics of 20WTG1500 silicon steel wafers are simulated and studied by using the Epstein square circle method. First, the loss-measured data are fitted based on the classical Bertotti loss model. When working, a Levenberg-Marquardt (L-M) algorithm is proposed to calculate the parameters of the loss model accurately. For the problem of significant calculation errors of hysteresis loss and stray loss in the classical loss separation model, a variable parameter closely related to the magnetic induction intensity is constructed by using the fixed parameter values of the classical loss model. Then, the loss improvement model is proposed. The accuracy of the improved model is proved by comparing the fitting results of the enhanced model with the measured data.
Study on Microstructure and Wear Resistance of WC-based Cermet Coatings Prepared by HVAF
Authors: Deng Chunyin , Liu Chengwei , Wang Xiaoping , Guan Haiyang , Zhu Ping , Wu Shuhui , Chen Guoxing
Published: July 2024

To mitigate the risk of vapor corrosion damage to the overflow mechanical parts, WC-based metal-ceramic coatings were applied to the surface of a 45-gauge steel substrate by supersonic air-assisted flame spraying (HVAF). The mechanical and wear-resistant qualities of the coating were identified by Vickers micro-hardness, ball-disc friction, and wear test, as well as optics, scanning electron, X-ray diffractometer, and white light interferometer systems. The findings demonstrate the layered structure of the WC-based coating, which is made up of the bonded phase and its distribution of hard phase particles that are diffusely dispersed. The coating is free of cracks, inclusions, and other defects, and its structure and organization are dense with a porosity of 0.86 ± 0.05%. The phenomenon of oxidative decarburization did not occur in the process of preparing the WC hard phase for WC-based metal-ceramic coatings. As a result, the coating’s micro-hardness of 11.83 ± 0.55 GPa is eight times that of the substrate. The results of comparing the three-dimensional abrasion patterns of the coating and the substrate reveal that the coating has superior abrasion resistance because its width and depth of abrasion are smaller than that of the substrate and a lot of furrows have formed on the substrate material’s surface. In contrast, the sprayed layer only had faint traces of abrasion. After three years of actual service, the impeller surface coating is essentially unaltered, which effectively addresses the issue of vapor corrosion damage to the slurry pump’s impeller and extends the pump’s service life to guarantee the overflow mechanical components operate safely and steadily.
Sensitivity of the global hydrological cycle to the altitude of stratospheric sulphate aerosol layer
Authors: K H Usha , Bala Govindasamy , Xavier Anu
Published: July 2024

Stratospheric aerosol geoengineering (SAG) has been proposed as one of the potential options to offset the impacts of anthropogenically induced climate change. Previous modelling studies have shown that the efficacy of the cooling via SAG increases with altitude of the aerosol layer. It has been also shown that the stratospheric heating associated with SAG could stabilize the tropical atmosphere and weaken the tropical hydrological cycle. Using a global climate model, we perform a systematic study by prescribing volcanic sulphate aerosols at three different altitudes (22 km, 18 km and 16 km) and assess the sensitivity of the global and tropical mean precipitation to the altitude. We find that even though the efficacy of cooling increases with altitude of the aerosol layer, the global and tropical mean precipitation changes are less sensitive to the height of the aerosol layer. This is because the magnitude of both the global and tropical mean precipitation reduction increases with aerosol altitude in response to increasing efficacy of aerosols, but this sensitivity related to the slow response is nearly offset by the sensitivity of fast precipitation adjustments to aerosol altitude. A perspective and analysis based on atmospheric energy budget is presented to explain the lack of sensitivity of the hydrological cycle to the altitude of the stratospheric sulphate aerosol layer.
Opposing approaches for enhancing energy efficiency in buildings
Authors: Rahman Motiar
Published: July 2024

This paper proposes two opposing approaches for enhancing energy efficiency in buildings as a part of combating climate change and summarizes interim outcomes from two ongoing research projects. The first project focuses on adopting sustainable design methodologies in new buildings, and the second one aims at ’greening’ old but otherwise economically viable and usable buildings. Finally, the paper points to the potential for an integrated platform for efficient energy management system for buildings for clients and/or owners, albeit with addressing a range of issues.
Study on effect of anti-bribery management system to the quality of authority organization operational management in construction industry
Authors: Ali Khairul Ammar Muhammad , Gau Patrick Robert , Bakar Amalina Amirah Abu
Published: July 2024

Unethical behaviours are quite common in the construction industries. This study aims to assess the impact of unethical behaviours within organization, and the effectiveness of implementing Anti-Bribery Management System (ABMS) within organization. Among many of the government organizations, the main target respondents for this study were workers such as consultants and contractors who had worked with organization ’B’. The organization is called as Organization ’B’ as this topic research might be sensitive. In this study, distribution of questionnaires via online platform was used as a quantitative method where a total of 54 respondents out of 146 expected sample sizes were obtained. Majority of the respondents are agreeable towards the unethical behaviour will contribute to lower the quality of their works as the mean value is greater than 4.0. Plus, the implementing of ABMS are also shows positive impact in the quality of their works as the mean value is also greater than 4.0. From overall respondents, the top 3 variables for unethical behaviour are ’Hard Control Measures’, ’Conflict of Interest’, and ’Lack Supervision’. As for the implementation of ABMS, the top 3 variables are ’ABMS Qualification’, ’Leadership’, and ’Policies and Procedures’.
Early warning system for headwater risk in Johor Eco-Park: First development life cycle report
Authors: Mahmud Mohd Rizaludin , Md Reba Mohd Nadzri , Aman Salim , Mahli Abd. Ramlizauyahuddin , Awang Nor Wahida
Published: July 2024

The headwater phenomenon is common in tropical waterfall and upper stream of Johor Eco-Park and threatens the visitors. Prior to that, an IoT system has been developed to issue early warning alert to the eco-park users on headwater risk. This paper presents the first life cycle report for the early headwater risk system in Gunung Pulai and Gunung Belumut Eco Park. Adapting the spiral development life cycle (SDLC), the system has completed its first complete spiral cycle whereas it has been implemented. This first SDLC report consists of four different parts: (i) problem and risk management, (ii) framework, (iii) system development, and (iv) testing and implementation. The alert on the site was triggered by the warning siren at the strategic locations. Simultaneously, the alert was also triggered in the web system and phone application to the eco-park management and prospective users to prevent from entering the premises. An auto generated report were also issued to provide potential disaster information for further action from the respective authorities. The developed system is subjected to be improved in the 2nd cycle by addressing several drawbacks including telecommunication signals, noise minimization, and threats from wild animals to the devices.
Characterization and prediction of acid mine drainage potential and metal solubility: Critical data for tailings and waste rock management in high sulfidation gold deposits
Authors: Eka Onwardana M , Ibrahim Abdul Haqi , Sedarta  , Tibri Tengku , Lismawaty
Published: July 2024

In the Purnama gold deposit at the Martabe mine of South Tapanuli District, North Sumatra Province, Indonesia, gold is extracted from the ore and the remaining fine-sized material is stored in the tailings storage facility (TSF) and waste rocks are placed as TSF embankments. Without proper management, tailings and waste rocks from mining can create acid mine drainage (AMD) and release toxic chemicals, posing significant risks to local ecosystems and residents in mining areas. To address this, a mineralogical and geochemical characterization study was investigated, as well as the leaching behavior of heavy metals in the tailings leach column tests (LCT) was conducted. Geochemical characterization showed quartz hornblende andesite and hornblende dacite as NAF materials; clay breccia, volcanic andesite, carbonaceous clay, volcanic breccia, and silica breccia as PAF materials. Further tests revealed that volcanic breccia, carbon clay, and volcanic andesite were classified as high-risk PAF materials, supported by XRD test results. Finally, the LCT results showed that volcanic breccia produced rapid acid drainage, with arsenic (45.9 mg L−1), copper (41.4 mg L−1), and manganese (14.1 mg L−1) being the main dissolved metals. It is important to manage PAF rocks and ensure the water leachate does not contain high concentrations of these metals.
Removal of diclofenac by photocatalysis utilizing crosslinked chitosan/oil-palm embedded titanium dioxide
Authors: Ghee K Z , Mokhtar Z , Hasan M
Published: July 2024

Photocatalytic degradation of diclofenac from aqueous solution utilizing cross-linked chitosan/oil palm ash embedded titanium dioxide composite beads (TiO2-COPA) was studied. Fourier Transform Infrared Spectroscopy (FTIR) was established to identify the functional groups of the composite beads. In order to conduct a kinetic and isotherm analysis, a number of parameters were taken into account, initial diclofenac concentration (10–50 mg L−1) and the dosage of composite beads (0.2–0.4 g). When compared to other concentrations, the initial concentration of diclofenac at 10 mg L−1 had the highest degradation percentage (51.32 %). With 69.32 % degradation, 0.4 g of titanium TiO2-COPA composite beads showed the greatest percentage. Photocatalytic degradation kinetics data were evaluated using pseudo-first order and pseudo-second order models. The rate constants for these models for under different initial concentrations were assessed. Kinetic studies proved that the photocatalysis conformed with the pseudo-first-order model. Langmuir Hinshelwood was utilized to analyze the equilibrium data at different diclofenac concentrations.
Impact of roots on the shear strength of root-reinforced soil on slopes
Authors: Rahman Ena Kartina Abdul , Jeludin Muneerah , Ratnayake Uditha , Musthapa Siti Maisarah
Published: July 2024

Tropical countries generally receive high rainfall throughout the year causing high runoff, wet soils and erosion. Undulating terrain from continuing erosion and frequent occurrences of landslides are the features of topographic evolution under such hydrological conditions. Vegetation is the only natural supporting factor that mitigates both erosion and landslides. It contributes to controlling soil erosion and strengthening of the soil by forming a mesh of roots at the surface. The objective of this study is to quantify soil strength on slopes when there is a presence of roots. Undisturbed samples were taken from two different depths of soil. The exact depth and distance varied slightly to avoid large roots and large gravel particles present in the natural environment. Immediately after sampling, the triaxial tests were performed under unconsolidated and undrained conditions. Subsequently, the tested samples were crushed carefully, to manually recover all roots and to classify the soil. From this study, it was observed that the presence of root fibres within the soil matrix has enhanced the soil strength through a binding action in the fibre-soil composite. The correlation between root content and shear strength is prominent near the surface and becomes less obvious in deeper soil layers when the root concentration becomes more sparsely distributed.
Indicative microzonation map of the contact zone between the kenny hill and limestone formation using active, passive and hybrid MASW methods
Authors: Zaki M F M , Ghazaly Z M , Bawadi N F , Ahmad M M , Nujid M M
Published: July 2024

The impact of the far-field earthquake generated by the Sumatra-Andaman earthquake (Richter scale of 9.3) was also felt by Malaysians. The ground motion triggered by this earthquake is caused by the shear wave velocity (Vs), particularly at a depth of 30 m (Vs30). Therefore, this dynamic soil properties need to be determined, which was evaluated using the active, passive, and hybrid multichannel analysis of surface waves (MASW) methods at 16 locations in the contact zone between the Kenny Hill and limestone formations in Kuala Lumpur, Malaysia. The Vs determined from the MASW for the contact zone ranging from 198 m/s to 286 m/s at the ground surface and from 376 m/s to 662 m/s at 30 m depth. In contrast, in the non-contact zone, Vs range from 212 m/s to 328 m/s at the ground surface and from 562 m/s to 921 m/s at 30 m depth. For Vs30, the contact zone has a minimum value of 280 m/s and a maximum value of 380 m/s, while the non-contact zone has a minimum value of 370 m/s and a maximum value of 530 m/s.
Numerical analysis on the differential settlement of geosynthetic reinforced soil integrated bridge system
Authors: Abdullah N H H , Ng K S , Jais I B M
Published: July 2024

Bump scenarios at the bridge approach frequently occur due to the differential settlement at the transition of the approach pavements and the bridge decks. The differential settlement between the approach roadway and the bridge deck is due to the greater consolidation settlement of the existing subsoil supporting the approach road relative to the foundation supporting the bridge deck. To overcome this problem, an economical method known as the geosynthetic reinforced integrated bridge system (GRS-IBS) is utilized. In this paper, a detailed description of the modelling approach to the GRS-IBS is presented. A validation analysis of the numerical model in terms of settlement, horizontal wall displacement, vertical pressure below the foundation, and lateral earth pressure shows good agreement with field observations. An analysis of the differential settlement of the GRS-IBS proves that it could eliminate the bump problems at the bridge approach. Then, further study was carried out to investigate the behaviour of GRS-IBS founded on soft soil. Finding shows that the bump formation for this system is out of tolerance. This finding aligns with the Federal Highway Administration (FHWA) guides, in which the GRS-IBS are not suitable where highly compressible soil is encountered. Several recommendations for future studies are given at the end of this paper.
Subgrade stabilization for road foundation in application for inundated area in Perlis, Malaysia
Authors: Ghazaly Z M , Bawadi N F , Ahmad M M , Nujid M M , Zaki M F M
Published: July 2024

Inundated areas, which are prone to frequent flooding, pose significant challenges for road infrastructure due to the adverse effects of water on subgrade soils. Thus, the objectives of this research were to identify and characterize the soil type from roadside of Kampung Bakau, Kangar, Perlis, and evaluate and propose the effective subgrade stabilization methods to enhance the performance and durability of road foundations under such condition. In this research, atterberg limit, standard proctor, and california bearing ratio (CBR) tests were conducted. For CBR test, 6 sets of soil samples were considered. In addition, during the CBR tests, soaked and unsoaked method were performed to simulate the condition of flooding. In general, the soil samples taken were characterized as high plasticity silt. Besides that, the results obtained from CBR test showed that lime with 8 % addition in mixture provides the highest strength which was 4.50 kN of load resisted at 2.00 mm penetration. Meanwhile, cement with 3 % addition in mixture showed the lowest strength observed in the CBR test which was 1.75 kN. In conclusion, this research showed that for high plasticity silt type of soil, the optimized subgrade stabilization method is by lime with 8 % addition in mixture.
Unconfined compressive strength of subgrade stabilized with coconut shell ash and lime in variation to curing time
Authors: Ramli Rozaini , Halim Mohammad Al Aiman Abdul , Mansor Syahirah
Published: July 2024

Many construction projects have encountered issues where the soil does not meet the necessary specifications for use as a subgrade layer. The high compressibility and low shear strength of these soils can lead to significant distortion when exposed to traffic loads. To address these issues, this study evaluated the impact of using natural additives namely coconut shell ash (CSA) admixed with lime. The research looked at how different types of treated soil and the quantity of chemicals used impacted the effectiveness of these additives. Variation portions of 2 %, 4 %, 6 %, 8 % and 10 % CSA with a constant 6% lime were used in the investigation. The study also examined how different variations of CSA and lime impacted the soil’s mechanical properties. Unconfined compressive strength (UCS) test was incorporated with curing times of 7, 14 and 28 days. The study's results found that using a combination of CSA and lime effectively improved the soil’s strength and durability. It conclusion, treated soil admixed with 6 % CSA and 6 % lime significantly improved the UCS as the value achieved 230.82 kN/m2 at 7 days. It's proven that untreated soil is more susceptible to water compared to treated soil.
Flexural strength behaviour of two-hollow interlocking concrete block inclusion with recycled concrete aggregate
Authors: Othman Nur Syahirah , Nor Noorsuhada Md , Saliah Soffian Noor Mat
Published: July 2024

In this study, the flexural strength of two hollow, interlocking concrete blocks (ICBs) made from 50 % recycled concrete aggregates (RCA) was determined under three–point loading. The study used a 1:4 concrete mix in which 50 % of the sand was replaced with recycled concrete aggregate. There was also a control mix without RCA and superplasticiser. The flexural strength, and compressive strength of the interlocking concrete blocks were determined after 7, 14 and 28 days of curing. The two-hollow interlocking concrete blocks (THICB) exhibited optimum strength for the elements, indicating the potential usability of RCA as a component of a mortar mix. The result shows that the compressive and flexural strength of the concrete blocks increased with the recycled concrete aggregate content. Replacing the fine aggregate with RCA of 0 and 50 % therefore has a significant effect on improving important properties of the ICBs.
Residual compressive strength of locally corroded circular CFST stub columns: An experimental study
Authors: Alatshan Faesal , Osman Siti Aminah , Hamid Roszilah A. , Mashiri Fidelis
Published: July 2024

Circular concrete-filled steel tubular (CFST) columns are widely used in civil engineering structures due to their high strength, stiffness, and ductility. However, these columns are susceptible to local corrosion damage, which can reduce their load-carrying capacity and durability. This paper presents an experimental investigation of the impact of local corrosion on the residual compressive strength of CFST stub columns. The experimental program included 9 CFST columns, which were divided into two groups: G1 and G2. G1 specimens were subjected to actual electrochemical corrosion, while G2 specimens were subjected to mechanical damage to simulate the corrosion effect. The experimental results included the tested columns’ corrosion profiles, failure modes, load-strain relationships, and load-carrying capacities. The main findings of this paper show that: (1) Different heights and thicknesses of corrosion profile representing the non-uniform localized corrosion. (2) Failure modes were mainly affected by the localized damage conditions, where the buckling occurred in the affected area. (3) Load-strain relationships exhibited elastic behavior initially, followed by nonlinear plastic behavior until reaching their ultimate compressive capacity. (4) The mechanical damage method can reasonably approximate the corrosion damage in CFST columns. This paper provides useful insights into the structural behavior of locally damaged CFST short columns.
Influence of seawater mixing on fresh and mechanical properties of oil palm shell lightweight aggregate concrete containing spent garnet
Authors: Jamaludin Nur Farah Aziera , Muthusamy Khairunisa , Hashim Muhammad Fitri Abu , Nazle Haiqal Akashah Mohamad , Othman Nor Hazurina
Published: July 2024

The rapid advancement in construction practices has led to a higher demand for natural aggregates in the production of concrete. Simultaneously, there has been an increase in pollution due to the improper disposal of industrial waste. Effective waste management has become imperative to prevent environmental harm. A sustainable solution involves incorporating waste materials such as oil palm shells (OPS) from the palm oil industry and spent garnet from shipbuilding activities into concrete production. This research aims to explore the impact of introducing spent garnet as a partial substitute for sand on the fresh and hardened properties of lightweight aggregate concrete (LWAC) made with OPS, mixed with seawater. Two sets of concrete mixes were prepared, varying the proportion of spent garnet as a partial replacement for fine aggregate, and both seawater and freshwater were used in the mixing process. Laboratory tests were conducted to evaluate workability, oven-dry density, and compressive strength of the concrete. The findings indicate that the workability decreases in freshwater but improves in both freshwater and seawater when spent garnet is added. All mixtures containing spent garnet qualify as LWAC. Notably, seawater-mixed OPS LWAC, with 10 % spent garnet, demonstrates the highest compressive strength. The use of seawater accelerates hydration, enhancing concrete strength compared to freshwater. In conclusion, incorporating spent garnet as a replacement for sand in concrete production results in environmentally friendly OPS LWAC. This approach contributes to waste reduction and minimizes reliance on landfills, promoting sustainable construction practices.
Shifting to sustainable micromobility: Understanding the factors influencing willingness to use e-scooters for campus-based travel of university students in Yogyakarta, Indonesia
Authors: Prayitno P A , Fardianto K Y , Sidhiq S , Kennyzyra M
Published: July 2024

E-scooters are experiencing a global rise in usage for urban micro-mobility, however, in Indonesia, their primary purpose is mostly for leisure activities. Notwithstanding legal constraints, the use of e-scooters for travel purposes is still predominantly lacking. The objective of this study is to gain insights into the attributes, movement behaviours, inclinations, and perspectives of prospective e-scooter riders, as well as their level of interest in utilising these vehicles for commuting inside the Universitas Islam Indonesia campus. A dataset consisting of information from 380 students was gathered and examined using descriptive statistics, chi-square tests of association, mean score analysis, and ordered probit models. The findings indicated that transportation on campus is predominantly dependent on motorised cars, accounting for 67 % of trips within a 2 kilometer radius. There were no significant factors observed that were linked to a propensity to use e-scooters. However, past experience with e-scooters was statistically significant for certain development scenarios. Male students were primarily influenced by factors such as discomfort during long distance journeys, inadequate infrastructure, and unfavourable weather conditions. In contrast, female students tended to prioritise the discomfort experienced when standing.
Analysis of land use change on flood discharge of Bengawan Solo Upstream sub-basin
Authors: Sutiyono Y , Wardhana P N
Published: July 2024

This study investigated land use changes of Bengawan Solo Upstream sub-watershed impact toward flood discharge between year 2015 and year 2019. The daily rainfall intensity was calculated statistically by using analysis frequency, and effective rainfall was acquired by compensation of potential storage and land use. Runoff discharge was calculated using the Nakayasu and the Soil Conservation Service method, while base flow discharge calculated using equation suggested by Hydrograph Synder Synthetic Gama-1. Land use change is represented by curve number (CN) value for year 2015 and year 2019 at values of 78.11 and 78.07, respectively. Decline of CN value was caused by surge of vegetation land area. Agricultural land CN value was not much different from settlement CN value. Overall, flood discharge that occurred plummeted between year 2015 and year 2019, although it was not significant. Decrease in flood discharge corresponds to decrease in CN value. Decline of CN value as much as 0.05 % yielded decrease of flood discharge as much as 0.16 % until 0.22 % related to return period.
Comparison of the missing rainfall data method in enhancing discharge estimation
Authors: Mahyun A W , Mohd Azrul Ismail M , Salwa M Z M , Isa Nurfitriah , Azlinda A G , Fauzi M R
Published: July 2024

Missing rainfall data can cause the results of an analysis to be inaccurate. This study aims to compare the performance of different methods in estimating missing rainfall data and to evaluate the estimated missing rainfall data method on hydrograph estimation. The methods used to estimate missing rainfall data in three selected stations include the arithmetic mean (AM) method, the inverse squared distance (ISD) method, and replacing missing value with zero value (ZERO). The study employs root mean square error (RMSE) to assess the accuracy and reliability of the methods. The estimated rainfall data are then utilized in Stormwater Management Modelling Software 5 (SWMM5) to evaluate the data impact on the discharge estimation. The results indicated that the AM method is the best method to estimate missing rainfall data by considering the lowest RMSE value equal to 1.185. In conclusion, the comparison of missing rainfall data methods in this study has shed light on their performance in enhancing discharge estimation.