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2024

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Articles 301 - 330 of 1004

Full-Text Articles in Materials Science and Engineering

Development And Processing Of Shape Memory Polymer Composites (Smpcs) For Application In Structural Robotics And Robotic Sensors., Kavish Sudan Aug 2024

Development And Processing Of Shape Memory Polymer Composites (Smpcs) For Application In Structural Robotics And Robotic Sensors., Kavish Sudan

Electronic Theses and Dissertations

Shape Memory Polymers (SMPs) have attracted significant attention since their introduction in the 1980s due to their remarkable ability to regain their original shape from a temporarily deformed state when exposed to an external stimulus, typically heat. This shape memory effect, driven by thermal transitions such as the glass transition temperature (Tg) or melting temperature (Tm), has made SMPs highly attractive for applications in soft robotics, aerospace, and biomedical devices. However, SMPs face challenges such as limited mechanical strength, thermal stability, and electrical conductivity, which hinder their broader adoption in advanced applications. To address these challenges, …


Development Of Iii-V And Iv Epitaxy On Sapphire Technology, Emmanuel Wangila Aug 2024

Development Of Iii-V And Iv Epitaxy On Sapphire Technology, Emmanuel Wangila

Graduate Theses and Dissertations

This research presents comprehensive insights into the epitaxial growth of germanium (Ge) on c-plane sapphire substrates using molecular beam epitaxy (MBE). The direct growth of Ge on sapphire typically yields three-dimensional (3D) Ge islands with diverse growth directions, multiple primary domains, and twinned crystals. However, incorporating a thin AlAs nucleation layer proves instrumental in enhancing surface and material quality. With a 10 nm AlAs layer, the achieved surface exhibits improved characteristics, including a smoother surface, single epitaxial orientation, sharper rocking curve, and a single domain. This study surpasses previous works by achieving a single primary domain and reducing twinning. Furthermore, …


Engineering The Properties Of Magnesium Aluminate Spinel Through Solid State Solutions, Robin Conner Aug 2024

Engineering The Properties Of Magnesium Aluminate Spinel Through Solid State Solutions, Robin Conner

All Theses

Magnesium aluminate spinel solid state solutions were prepared via the coprecipitation method and calcined in air at 900 °C for 2 h. The manipulation of magnesium aluminate spinel’s microstructure through the formation of solid state solutions with zinc and gadolinium substituting for magnesium was investigated. X-ray diffraction (XRD) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR FTIR) confirmed the formation of a single cubic crystalline phase. The luminescence properties were investigated by radioluminescence (RL) under X-ray excitation and thermoluminescence (TL) measurements. In the case of zinc, all concentrations of the solid state solutions showed similar luminescence with bands at …


High-Quality Single-Step Growth Of Gaas On C-Plane Sapphire By Molecular Beam, Emmanuel Wangila, Calbi Gunder, Mohammad Zamani-Alavijeh, Fernando Maia De Oliveira, Serhii Kryvyi, Aida Sheibani, Yuriy I. Mazur, Shui-Qing Yu, Gregory J. Salamo Aug 2024

High-Quality Single-Step Growth Of Gaas On C-Plane Sapphire By Molecular Beam, Emmanuel Wangila, Calbi Gunder, Mohammad Zamani-Alavijeh, Fernando Maia De Oliveira, Serhii Kryvyi, Aida Sheibani, Yuriy I. Mazur, Shui-Qing Yu, Gregory J. Salamo

Physics Faculty Publications and Presentations

We report on the growth of high-quality GaAs semiconductor materials on an AlAs/sapphire substrate by molecular beam epitaxy. The growth of GaAs on sapphire centers on a new single-step growth technique that produces higher-quality material than a previously reported multi-step growth method. Omega-2theta scans confirmed the GaAs (111) orientation. Samples grown at 700 °C displayed the highest crystal quality with minimal defects and strain, evidenced by narrow FWHM values of the rocking curve. By varying the As/Ga flux ratio and the growth temperature, we significantly improved the quality of the GaAs layer on sapphire, as compared to that obtained in …


Chemical Recycling Of Bio-Based Polyurethane Foams: Evaluating Bio-Based Glycols In Comparison To Petroleum-Based Glycols, Anirudh Thorbole Mr. Jul 2024

Chemical Recycling Of Bio-Based Polyurethane Foams: Evaluating Bio-Based Glycols In Comparison To Petroleum-Based Glycols, Anirudh Thorbole Mr.

Electronic Theses & Dissertations

The paradigm shift towards bio-based polyurethane foams (bio-PUF) has significantly increased post-consumer waste. To address this issue, this research represents a novel approach to enhance sustainable development in the recycling industry by replacing traditional petroleum-based glycols with sustainable bio-based alternatives. This study explores the glycolysis of bio-PUF using bio-based SG-522 glycol and polyethylene glycol (PEG) for comparison. The findings from this research as outlined, reveal no significant differences in depolymerization time between the two glycols, achieving proper depolymerization and high recovery yields of over 95% after solvent purification. Comprehensive FT-IR and NMR analyses confirmed the successful degradation of bio-PUF and …


Metal Casting Furnace Design Development Using Computer Simulation, Ramadhan Wahyu Irianto, Yanuar R.A. Pradana, Suprayitno Suprayitno Jul 2024

Metal Casting Furnace Design Development Using Computer Simulation, Ramadhan Wahyu Irianto, Yanuar R.A. Pradana, Suprayitno Suprayitno

Journal of Mechanical Engineering Science and Technology (JMEST)

Metal foundries still rely heavily on crucible furnaces. The current furnace design, which is currently being used by the partner industry, has been found to be not properly designed and will result in a reduction in efficiency. CFD simulation will be used to find the optimal melting furnace design. This research simulation consists of 3 stages: pre-processing, solving, and post-processing. There are two furnace geometries, cylindrical and hexagonal, while the burner location will be divided into 3 positions, namely P1, P2, and P3. The most optimal furnace design will be used as a basis for the verification testing process. The …


Evolution Of Residual Stress, Crystal Orientation, And Texture On Preheating Weld Treatment Of Low Carbon Steel Astm A572 Grade 42, Suratno Adi Saputro, Andoko Andoko, Poppy Puspitasari Jul 2024

Evolution Of Residual Stress, Crystal Orientation, And Texture On Preheating Weld Treatment Of Low Carbon Steel Astm A572 Grade 42, Suratno Adi Saputro, Andoko Andoko, Poppy Puspitasari

Journal of Mechanical Engineering Science and Technology (JMEST)

Preheating is one type of heat treatment on the material prior to starting the welding process by increasing the temperature of the material. It is used to reduce the cooling rate during the welding processes to minimize the risk of residual stress and cracking during welding. Besides the benefits of welding, it also has a negative impact, especially on the integrity of the material, because the heating process at high temperatures will cause residual stress, which will affect the mechanical properties, chemical composition, and microstructure of the material, especially on Heat Affected Zone (HAZ). This study aims to analyze the …


Static And Modal Analysis Of A Box Structured Satellite Deployment Mechanism With Self-Actuated Torsion Joint, Dongping Sheng, Renzhe Ma, Chun Su Jul 2024

Static And Modal Analysis Of A Box Structured Satellite Deployment Mechanism With Self-Actuated Torsion Joint, Dongping Sheng, Renzhe Ma, Chun Su

Journal of Mechanical Engineering Science and Technology (JMEST)

A brand-new satellite deployment mechanism with boxed structure and self-actuated torsion joints is proposed and an effective method to verify the feasibility of this mechanism is established in this paper. This mechanism has the characteristics of high base frequency, high ratio of deployed and folded space occupation ratio. In order to meet the design requirements, the related analysis and optimization need to be conducted, and several conclusions are obtained. Firstly, the modal analysis of deployment mechanism at folded and fully deployed state is analyzed, and the result showed that the proper wall thickness is the key parameter to satisfy the …


A Review Of Fault Detecting Devices For Belt Conveyor Idlers, Fahad Alharbi, Suhuai Luo Jul 2024

A Review Of Fault Detecting Devices For Belt Conveyor Idlers, Fahad Alharbi, Suhuai Luo

Journal of Mechanical Engineering Science and Technology (JMEST)

The shift towards automated inspection methods represents considerable progress in conveyor system maintenance, enhancing safety and efficiency while posing challenges in data analysis and implementation costs. This study critically analyses sensor technologies and inspection methods for detecting faults in conveyor belt idlers, highlighting their essential role in preserving the operational integrity of industrial conveyor systems. By synthesizing various research findings, the study assesses the effectiveness of different sensor devices in identifying defects, including built-in sensors, fixed sensor options like acoustic, ultrasonic sensors, cameras, accelerometers, and Distributed Optical Fibre Sensors (DOFS), as well as mobile sensor systems. Our findings emphasize the …


Analysis Of Avgas Fuel Spraying Schemes Using The Ansys Application Approach, Dimas Endrawan Putra, Nasrul Ilminnafik, M Fahrur Rozy Hentihu, Muh. Nurkoyim Kustanto, Danang Yudistiro, Skriptyan N.H. Syuhri Jul 2024

Analysis Of Avgas Fuel Spraying Schemes Using The Ansys Application Approach, Dimas Endrawan Putra, Nasrul Ilminnafik, M Fahrur Rozy Hentihu, Muh. Nurkoyim Kustanto, Danang Yudistiro, Skriptyan N.H. Syuhri

Journal of Mechanical Engineering Science and Technology (JMEST)

Avgas fuel consumption on Cessna trainer aircraft is very high. However, there has been little research regarding spray impacts in Cessna aircraft engines. The phenomenon of avgas spray colliding with the cylinder wall may occur during fuel injection, resulting in a changed spray radius and height, which will affect the mixing of fuel and air. In several aspects, this affects engine performance and exhaust emissions on Cessna aircraft. This research aims to determine and study the phenomenon of spray impact on avgasfueled aircraft engines. The fuel spray in the study occurred in the combustion chamber using pressure from a fuel …


Effect Of Addition Titanium Dioxide Nanoparticle On Properties Of Pineapple Leaf Fiber Mediated Tempo Oxidation, Rahmad Ikrom Ramadhan, Heru Suryanto, Ahmad Atif Fikri, Aminnudin Aminnudin, Jibril Maulana, Faqih Fadillah, Mohamed T. Mito, Kemal Masera Jul 2024

Effect Of Addition Titanium Dioxide Nanoparticle On Properties Of Pineapple Leaf Fiber Mediated Tempo Oxidation, Rahmad Ikrom Ramadhan, Heru Suryanto, Ahmad Atif Fikri, Aminnudin Aminnudin, Jibril Maulana, Faqih Fadillah, Mohamed T. Mito, Kemal Masera

Journal of Mechanical Engineering Science and Technology (JMEST)

Indonesia is an agricultural country with the potential to grow many plants as natural fiber sources. In order to improve its properties, natural fiber needs to be treated by applying nanomaterial so that it can compete with the characteristics of synthetic fibers. The study aims to determine the influence of adding titanium dioxide (TiO2) nanoparticles on pineapple leaf fiber (PALF) characteristics. The PALF was collected from the Subang plantation (Indonesia). The chemical treatment was carried out with pre-treatment using an alkalization process for 3 hours, and the oxidation process was carried out with TEMPO. TiO2 nanoparticle grafting was carried out …


Analysis Of Ballistic Capability In Making Bulletproof Multilayers Using Woven Ramie Fiber, Hardfacing Metal With Epoxy Matrix For Bulletproof Vests, Rizal Wahyu Permana, Syamsul Hadi, Bima Cahya Maula Dana Jul 2024

Analysis Of Ballistic Capability In Making Bulletproof Multilayers Using Woven Ramie Fiber, Hardfacing Metal With Epoxy Matrix For Bulletproof Vests, Rizal Wahyu Permana, Syamsul Hadi, Bima Cahya Maula Dana

Journal of Mechanical Engineering Science and Technology (JMEST)

Bulletproof material in level III bulletproof vests must be created using hard and soft materials to prevent bullet penetration. Kevlar and SiC + PE are imported materials used as armor in bulletproof vests. The use of Kevlar and SiC is very dependent on foreign sources with high prices. An innovation was carried out by making bulletproof material using cheaper multilayer methods involving metal from hardfacing welding as a hard layer and ramie fiber as a soft layer with an epoxy matrix. To see the level of penetration and surface morphology structure in the specimens, 9 variations were made: 3 layers …


Computational Fluid Dynamics Analysis Of Temperature Distribution In Solar Distillation Panel With Various Flat Plate Materials, Trismawati Trismawati, Hendry Y. Nanlohy, Helen Riupassa, Susi Marianingsih Jul 2024

Computational Fluid Dynamics Analysis Of Temperature Distribution In Solar Distillation Panel With Various Flat Plate Materials, Trismawati Trismawati, Hendry Y. Nanlohy, Helen Riupassa, Susi Marianingsih

Journal of Mechanical Engineering Science and Technology (JMEST)

As the world population continues to grow, the demand for clean water is increasing daily, making it a crucial resource to access. However, there are ways to harness abundant resources like solar energy and seawater to produce clean water. The present studies have conducted experimental investigations to convert seawater into freshwater using solar stills, where solar energy is utilized as the primary heat source for evaporation. The temperature distribution inside the solar stills was analyzed using a flat plate made of three different materials: copper, stainless steel, and aluminum. To examine the temperature distribution and performance of the solar stills, …


Comparative Analysis Of The Effect Dual Spark Ignition And Single Spark Ignition On Performance And Exhaust Emissions In Bioethanol-Fueled Engines, Avita Ayu Permanasari, Ahmad Faizal Wahidin, Hasan Ismail, Erwin Komara, Poppy Puspitasari, Gina A. Lorenzo Jul 2024

Comparative Analysis Of The Effect Dual Spark Ignition And Single Spark Ignition On Performance And Exhaust Emissions In Bioethanol-Fueled Engines, Avita Ayu Permanasari, Ahmad Faizal Wahidin, Hasan Ismail, Erwin Komara, Poppy Puspitasari, Gina A. Lorenzo

Journal of Mechanical Engineering Science and Technology (JMEST)

Bioethanol is an alternative fuel that has a high octane value of around 100 to 110, making it difficult to be applied to spark ignition engines directly. So, it is necessary to make adjustments, including increasing combustion efficiency and thermal efficiency of the combustion chamber by increasing the compression ratio and adjusting the ignition system, both in single spark ignition (SSI) and dual spark ignition (DSI) types. The study aims to determine the effect of SSI and DSI applications on engine performance, specific fuel consumption (SFC), and exhaust emissions using 96% and 99% levels of bioethanol fuel. The results showed …


Performance Enhancement Of Dye Sensitized Solar Cell (Dssc) Through Tio2/Rgo Hybrid: Comprehensive Study On Synthesis And Characterization, Rustan Hatib, Khairil Anwar, Ramang Magga, Muh Anjas Astak, Denny Widhiyanuriyawan, Wardoyo Wardoyo Jul 2024

Performance Enhancement Of Dye Sensitized Solar Cell (Dssc) Through Tio2/Rgo Hybrid: Comprehensive Study On Synthesis And Characterization, Rustan Hatib, Khairil Anwar, Ramang Magga, Muh Anjas Astak, Denny Widhiyanuriyawan, Wardoyo Wardoyo

Journal of Mechanical Engineering Science and Technology (JMEST)

The TiO2 film is immersed in a graphite oxide solution, preparing it for thermal reduction, which converts the graphite oxide to reduced graphene oxide (rGO). This process produces rGO hybrid TiO2 photoanodes for dye-sensitized solar cells (DSSC). rGO in the TiO2 structure prevents electron recombination and improves overall efficiency. The main advantage of this method is its ability to prevent loss of rGO during the sintering process, which is a common problem with other methods. The study investigated heating temperatures ranging between 300˚C, 350˚C, 400˚C, 450˚C, and 500˚C to determine optimal conditions. The presence of rGO in the photoanode structure …


Crashworthiness And Deformation Pattern Analysis Of Single And Double Wall With Addition Infill Structure, Redyarsa Dharma Bintara, Moch. Agus Choiron, Yahya Zakariya, M. Hasbi Ash Shiddieqy, Fajar Adi Pratama Jul 2024

Crashworthiness And Deformation Pattern Analysis Of Single And Double Wall With Addition Infill Structure, Redyarsa Dharma Bintara, Moch. Agus Choiron, Yahya Zakariya, M. Hasbi Ash Shiddieqy, Fajar Adi Pratama

Journal of Mechanical Engineering Science and Technology (JMEST)

Ship collisions are a phenomenon that often occurs in maritime transportation. One part of the ship that often experiences damage is the ship's wall (hull). This research aims to analyze and compare deformation patterns, stress distribution, and energy absorption in three wall models, single wall, double wall, and double wall, with the addition of infill structures. The infill structure used Polylactic Acid (PLA) polymer material because it provided convenience in the manufacturing process, while the walls of the test model used Aluminum 6063 material. The test model was developed by carrying out the design process using CAD software. Furthermore, a …


Durability Of Thermoplastic Polyurethane Round Belt Joint With Variations In Heating Methods And Cutting Shapes, Achmad Sabilarrosyad Prawiro Kusumo, Anggit Murdani Jul 2024

Durability Of Thermoplastic Polyurethane Round Belt Joint With Variations In Heating Methods And Cutting Shapes, Achmad Sabilarrosyad Prawiro Kusumo, Anggit Murdani

Journal of Mechanical Engineering Science and Technology (JMEST)

Thermoplastic polyurethane round belts are widely used for conveyors in various industries, particularly in the food and beverage industry, due to their flexible and abrasion-resistant characteristics. These belts are also popular in manufacturing industries because of their ease of joint. However, a common issue arises when the conveyor belt breaks during the production process. This problem can be attributed to the lack of parameters in the belt joining process at companies. Operators do not have a standard parameter for the joining process. When there is an improper joining operation of an operator, the conveyor belt could fail earlier than the …


Heuristic Approach To Comparing The Environmental Impacts Of Carbon Nanotube Production Methods, Ahmad Atif Fikri, Irham Fadlika, Albarrobi Nabila Saeful, Krisna Dwipa Muhdi, Daniel Febrian Pratama, Nasir Garba Bello Jul 2024

Heuristic Approach To Comparing The Environmental Impacts Of Carbon Nanotube Production Methods, Ahmad Atif Fikri, Irham Fadlika, Albarrobi Nabila Saeful, Krisna Dwipa Muhdi, Daniel Febrian Pratama, Nasir Garba Bello

Journal of Mechanical Engineering Science and Technology (JMEST)

Carbon Nanotubes (CNTs) production so far has its own advantages and disadvantages. Some methods that can be used in producing CNTs are chemical vapor deposition (CVD), laser ablation, and arc discharge. The three methods have their own requirements, this causes different environmental impacts on each method. Studies into the environmental impact of the CNTs production process found that during thermal pretreatment of the reactant gas, more than 45 by-products were formed, including methane, volatile organic compounds, and polycyclic aromatic hydrocarbons. Calculating the environmental impact of CNTs production method often has challenges in implementation, because each production process has different systems …


Mechanical Properties Of Corner Lap-45 Types Joined Using Friction Stir Welding, Widia Setiawan, Nugroho Santoso, Felixianus Eko Wismo Winarto, Radhian Krisnaputra, Wirawan Widya Mandala, Jibril Maulana Jul 2024

Mechanical Properties Of Corner Lap-45 Types Joined Using Friction Stir Welding, Widia Setiawan, Nugroho Santoso, Felixianus Eko Wismo Winarto, Radhian Krisnaputra, Wirawan Widya Mandala, Jibril Maulana

Journal of Mechanical Engineering Science and Technology (JMEST)

Solid welding has always been concerned with probe design, pins, and joint strength. Many researchers have conducted studies on joints, such as butt joints, lap joints, and T joints, but the results show low strength. This study analyzes the mechanical properties of a new design of a 90o angle joint joined by friction stir welding. This study connected aluminum 6061 using the friction stir welding method using a rectifying jig and a probe with EMS 45 material. The corner joint designs used corner-lap 45 with feed rate as independent variables in 6, 8, 10, 15, and 30 mm/min and dependent …


Study Of A Remote Wind Resource Assessment System Integrated With Internet Of Things, Filian Arbiyani, Filbert Filbert, Anthony Nathanael Theo Jul 2024

Study Of A Remote Wind Resource Assessment System Integrated With Internet Of Things, Filian Arbiyani, Filbert Filbert, Anthony Nathanael Theo

Journal of Mechanical Engineering Science and Technology (JMEST)

Wind energy is an emerging and popular source of clean energy due to its non-polluting nature and low cost. The efficient use of wind energy requires accurate and precise wind parameter measurements, which is where wind resource assessment (WRA) comes into play. The IoT and cloud-based systems have been applied to remote monitoring systems and provide crucial solutions for data acquisition, storage, and analytics in wind energy technology. This study aims to build a remote WRA system integrated with the Internet of Things. This study utilizes an Arduino Uno microcontroller, RK100-01 wind speed sensor, BMP280 temperature and pressure sensor, and …


Experimental Study On Reinforced Geogrid Of Construction And Demolition Wastes Based On Dic Technology, Tan Peng, Li Hai, Li Xiangping, Gu Fan, Zhang Junhui Jul 2024

Experimental Study On Reinforced Geogrid Of Construction And Demolition Wastes Based On Dic Technology, Tan Peng, Li Hai, Li Xiangping, Gu Fan, Zhang Junhui

Journal of China & Foreign Highway

In order to control differential settlement caused by new and old subgrade connections after expressway reconstruction and expansion,this paper proposed a layered treatment structure for the loose steps of the old road with high water content.A layer of construction and demolition waste was laid on the step surface of the old road to wrap the geogrid.The treatment effect was compared with that of sand wrapping and lime mixing,and the digital speckle correlation (DIC) was used to observe the reinforced influence zone,so as to determine the thickness of different layers of the subgrade wrapped by construction and demolition wastes.The particle rotation …


Experimental Study On Effect Of Temperature On Bound Water Adsorption And Deformation Of High Liquid Limit Soil, Zi Yinhui, Shen Xuning, Zhang Hao, Zhang Rui, Li Lu Jul 2024

Experimental Study On Effect Of Temperature On Bound Water Adsorption And Deformation Of High Liquid Limit Soil, Zi Yinhui, Shen Xuning, Zhang Hao, Zhang Rui, Li Lu

Journal of China & Foreign Highway

In order to study the effect of temperature change on the bound water content adsorbed by high liquid limit clay and the deformation law of high liquid limit clay embankment,the high liquid limit clay in Hainan Province was selected as the primary research object and compared with the low liquid limit sand in Hunan Province.The effect of temperature on the bound water content adsorbed by high liquid limit clay was explored through a nuclear magnetic resonance test.In addition,the effect of temperature on the deformation of high liquid limit clay embankments was analyzed through the consolidation test with a temperature-controlled consolidometer.The …


Stability Analysis Of High And Steep Bank Slope Of Jinqi Bridge On Wudang‑Changshun Expressway, Wang Hao Jul 2024

Stability Analysis Of High And Steep Bank Slope Of Jinqi Bridge On Wudang‑Changshun Expressway, Wang Hao

Journal of China & Foreign Highway

Jinqi Bridge on the Wudang-Changshun Expressway in Guizhou Province crosses the Maotiao River,and the poor geological conditions such as dangerous rock mass and collapse accumulation body on the bank slope of the river are relatively developed,which seriously affects the site selection and safety of the bridge.In order to study the stability of the high and steep bank slope of the bridge,the paper explored the main poor geological conditions in the bridge site through a comprehensive air-ground investigation.By means of numerical analysis,InSAR,and other technologies,the movement range of dangerous rock mass on the bank slope was quantitatively evaluated.The stability and deformation mode …


Shear Creep Characteristics And Slope Deformation Mechanism Of Siliceous Slate, Li Jian, Yan Liangyu, Yu Kaibing, Li Ming, Yan Tingzhou, Zhao Jia Jul 2024

Shear Creep Characteristics And Slope Deformation Mechanism Of Siliceous Slate, Li Jian, Yan Liangyu, Yu Kaibing, Li Ming, Yan Tingzhou, Zhao Jia

Journal of China & Foreign Highway

To study the time-dependent creep effect of siliceous slate and the deformation and failure evolution law of high slope,in this paper,the shear creep test of indoor rock mass was carried out to plot the shear creep duration curves of siliceous slate under different normal stresses,the shear displacement-time curve,and the creep rate-time curve under different normal loads and shear loads.The average creep rate and shear load variation of siliceous slate were studied,and the long-term shear strength parameters of siliceous slate were determined by the steady-state creep rate method.The results show that in the creep test,the sensitivity of cohesion is significantly greater …


Working Performance Of Rigid Airfield Runway Considering Influence Of Cavity Depth, Dai Xuan, Li Zhao, Cai Jing, Li Yue, Liu Guoguang, Qi Lin Jul 2024

Working Performance Of Rigid Airfield Runway Considering Influence Of Cavity Depth, Dai Xuan, Li Zhao, Cai Jing, Li Yue, Liu Guoguang, Qi Lin

Journal of China & Foreign Highway

In order to analyze the influence of cavity depth on runway safety,a numerical simulation was carried out using the finite difference method.A total of 208 sets of different working conditions were designed by taking into account factors such as different aircraft types,runway dimensions,and cavity depth and area.Based on the runway life model considering the exponential decay of the structural condition,an analytical method was proposed to evaluate the impact of the cavity on the runway life.The results show that the bending and stress of the runway increase gradually with the increase in the cavity depth,but the growth rate is getting slower …


Intelligent Compaction Of Asphalt Pavement And Its Key Influencing Factors, Zhu Huifang, Wang Liang Jul 2024

Intelligent Compaction Of Asphalt Pavement And Its Key Influencing Factors, Zhu Huifang, Wang Liang

Journal of China & Foreign Highway

Intelligent compaction,as a new type of road construction quality monitoring and management technology,has been widely used in the compaction process of asphalt pavement.However,due to the lack of understanding of the compaction process and the interaction mechanism between asphalt mixture particles,the problems of over-compaction and non-uniformity of compaction often occur in the actual construction,which seriously affects the quality of road construction and service performance.In this study,through the combination of the engineering field and indoor tests,the variation characteristics of asphalt mixture compaction with the number of compaction were analyzed by using the semi-variance function of the geostatistical model,and the effect of temperature …


Properties And Mechanism Of Reclaimed Asphalt Based On Sbs Structure Repair, Feng Xinjun, Yang Hongyang, Xiao Honghai, Zhu Ziqiang Jul 2024

Properties And Mechanism Of Reclaimed Asphalt Based On Sbs Structure Repair, Feng Xinjun, Yang Hongyang, Xiao Honghai, Zhu Ziqiang

Journal of China & Foreign Highway

At present,the common asphalt regenerant is used for treating the aged styrene-butadiene-styrene (SBS) modified asphalt in China,which fails to repair the SBS cross-networking structure,resulting in the poor regeneration effect of the aged SBS modified asphalt.In this study,a new reactive regenerator containing a structural repair agent,extractive oil,plasticizer,solubilizer,and a small amount of SBS was used to regenerate the aged SBS modified asphalt.The conventional properties and rheological properties of reclaimed SBS modified asphalt were studied by three index tests,Brookfield viscosity test,dynamic shear rheological test,and low temperature bending rheological test.Then,a fluorescence microscope and infrared spectrometer were used to study the regeneration mechanism of the …


Influence Of Lateral Constraint Conditions And Compactness On Compression Characteristics Of Compacted Loess In Northern Shaanxi, Chang Yinghong, Zhao Jinpeng, Zhang Xiaozhou, Yang Hao, Li Zhe, Shao Dengfeng, Liu Lulu Jul 2024

Influence Of Lateral Constraint Conditions And Compactness On Compression Characteristics Of Compacted Loess In Northern Shaanxi, Chang Yinghong, Zhao Jinpeng, Zhang Xiaozhou, Yang Hao, Li Zhe, Shao Dengfeng, Liu Lulu

Journal of China & Foreign Highway

In recent years,with the rapid development of road engineering construction,subgrade settlement caused by vertical compression of compacted loess has become increasingly serious.The previous research on the deformation of compacted loess mostly focuses on moisture content,porosity,saturation,and other aspects,ignoring the influence of lateral constraint conditions and different compaction on compacted loess.To address these issues,based on the reconstruction and expansion project of G 307 road in northern Shaanxi,this paper selected compacted soil samples of subgrade on site to carry out indoor compression tests.By applying different lateral constraint conditions,the stress-strain curves of compacted loess subjected to vertical multistage load under different compactness and confining …


Effect Of Aging Temperature On Properties Of Sealant Under Field Construction Conditions, Liu Hanchao, Teng Xinhua, Zhang Jingyan, Zhang Kaihua, Lin Hui Jul 2024

Effect Of Aging Temperature On Properties Of Sealant Under Field Construction Conditions, Liu Hanchao, Teng Xinhua, Zhang Jingyan, Zhang Kaihua, Lin Hui

Journal of China & Foreign Highway

In order to study the influence of short-term aging temperature on the properties of sealant,a sealant was prepared,and field construction conditions were simulated.The properties of the sealant before and after short-term aging at 180‒220 ℃ were tested.The viscoelastic properties,physicochemical properties,and microstructures of the sealant were studied,and the mechanism of property changes was discussed.The results show that the cone penetration and flow value of the aged sealant decrease,while the softening point and elastic recovery rate increase.Aging at high temperature (>180 ℃) for a short time and low temperature (160 ℃) for a long time will cause obvious property changes.The tensile …


Experimental Study On Capillary Water‑Holding Characteristics Of Loess Backfill In Ecological Ditches, Nan Yalin, Zhang Xiaoyu, Chen Hong, An Peng, Liu Kui, Camara Ibrahima Kalil Jul 2024

Experimental Study On Capillary Water‑Holding Characteristics Of Loess Backfill In Ecological Ditches, Nan Yalin, Zhang Xiaoyu, Chen Hong, An Peng, Liu Kui, Camara Ibrahima Kalil

Journal of China & Foreign Highway

The municipal ecological ditches have the basic functions of accumulating water for infiltration in the rainy season and conserving moisture in the dry season.However,the design of loess backfill in ecological ditches is based on no evidence,which often leads to landscape vegetation drowning in the rainy season or dying in the dry season.For this reason,a study was carried out by remoulding loess with a small-size capillary water rise height test,a large-size water-holding characteristic model test,and an unsaturated numerical analysis.The results show that the final capillary water rise height of the soil column can reach 100 cm when the dry density is …