Materials Science and Engineering Commons^™

Computational Studies Of Charge-Transfer Mechanisms In Electrochemical Materials, Mohammadreza Reza Nouri

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Understanding charge transfer mechanisms of electrochemical reactions is critical for advancing a variety of electrochemical energy storage and conversion technologies such as water electrolysis, fuel cells, and batteries. (Photo)electrochemical water splitting, involving OER at the anode and HER at the cathode, presents an environmentally friendly way of storing energy from renewable sources in the form of pure hydrogen. While a lot of emphasis has been placed on developing highly active and stable OER/HER catalysts, our atomic-level understanding of the underlying charge transfer mechanisms falls behind.

In this work, we focus on both Faradaic and non-Faradaic charge transfer mechanisms to investigate …

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 …

Secondary Electron Yield Of Metals, Alloys, And Metal Oxides From First Principles Based Monte Carlo Simulations, Raul E. Gutierrez

Electrical and Computer Engineering ETDs

Density Functional Theory (DFT) based Monte Carlo (MC) simulations of the Sec-
ondary Electron Yield (SEY) of metals, alloys, and metal oxides are performed to
find material properties that could help reduce or influence the multipactor effect.
In order to accurately model the SEY of materials, knowledge of the frequency- and
momentum-dependent Energy Loss Function (qDepELF) is required. The qDepELF
is difficult to determine from experiment; however, it can be calculated from first
principles. The DFT-MC approach for simulating the secondary electron genera-
tion, propagation, and emission processes is described herein. Material properties,
which are calculated using DFT and used …

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

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 …

Research On Performance Of Coal Gangue Concrete, Wang Jiliang, Ma Wenhui, Xu Weidong, Lyu Zhigang

Journal of China & Foreign Highway

Coal gangue is an industrial solid waste produced in the process of raw coal mining.It has a large stock and a relatively low utilization rate.Using coal gangue as concrete aggregate can not only solve the environmental pollution caused by coal gangue storage but also make up for the shortage of natural sand and gravel resources，which opens up an effective way for the large-scale utilization of coal gangue.According to the application characteristics of coal gangue as concrete aggregate，the chemical component，mineral composition，and physical properties of coal gangue were systematically analyzed.The influence of coal gangue as aggregate on the working performance，mechanical properties，volume stability，and …

Experimental Study On Shear Performance Of Uhpc‑Nc Interface, Wan Zhiyong, Chen Jianping, He Shaohua, Huang Xu, Sun Xiangdong

Journal of China & Foreign Highway

Ultra-high performance concrete （UHPC） has great application prospects in engineering structure reinforcement.The reliability of the bonding properties at the interface between the new UHPC reinforcement layer and the old concrete structure is critical for ensuring the serviceability of the reinforced structures.To determine the influence of different interface treatments on the bonding properties at the interface between the UHPC and normal concrete （NC），six Z-shaped UHPC-NC bonding specimens were designed，and the bonding properties of the UHPC-NC with three different kinds of interface，namely smooth，chisel，chisel + reinforced，were investigated.In addition，nonlinear finite element models for the concrete interface were established to determine the distribution law of …

Application Of Sequential Quadratic Programming Method In Cable Force Adjustment Of Cable‑Stayed Bridges, Xu Yufeng, Zhu Mengyang, Chen Si, Xie Yunfei

Journal of China & Foreign Highway

When the construction of a cable-stayed bridge enters the completion stage，due to various factors，there is a certain error between the actual alignment and internal force of the structure and the theoretical completion state，and it is usually necessary to adjust the cable force.In order to calculate the cable force adjustment of a cable-stayed bridge in the adjustment stage，a method based on an influence matrix and sequential quadratic programming was proposed to solve the cable force adjustment.A large-span hybrid girder cable-stayed bridge was taken as the background，and the alignment and internal force response values of the structure with varying cable units were …

Protection Design Of Middle Piers Of Overpass Bridges Based On Double Protection Concept, Lyu Sizhong, Wang Xin, Guo Jianmin, Liu Siyuan, Li Yuxin, Yang Fuyu

Journal of China & Foreign Highway

The collision accident types of middle piers of overpass bridges were summarized and analyzed，and it was proven that anti-collision and anti-scratching were two important requirements of pier protection.Then，the new concept of double protection and corresponding technical schemes were put forward.The first protection adopted the way of setting concrete barriers or ship-shaped elevating members on the periphery of the pier to prevent vehicles from impacting the pier，and the second protection used the self-wrapped steel plate or aluminum foam plate to prevent vehicles from scratching the pier.The safety of the pier protection structure schemes was verified by computer simulation and unit test，and …

Research On Yolov 5‑Ganomaly Joint Algorithm For High‑Strength Bolt Detection, Xie Haibo, Zhu Weijun, Zhang Bi2, Zhang Dahai

Journal of China & Foreign Highway

High-strength bolt loosening detection of bridges faces problems such as heavy workload，small targets，many anomalies，and difficult collection.Therefore，this paper proposed a semi-supervised deep learning model，which could obtain the bolt loosening detection model even with a small number of negative samples and solve the problem of unbalanced model training samples.The accuracy of the YOLOv 5-CT model for bolt target detection reached 98.33%.By preprocessing bolt data，the reconstruction ability of bolt images by the Ganomaly model was improved.When the hidden space vector value was 100，the model had the highest SAUC and the best discriminant performance.In the model test stage，the threshold of abnormal fraction was set …

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 …

Temperature And Strain Development Characteristics Of Tunnel Concrete Based On Double Grating Sensors, Fang Jianping, Zhang Mengxi, Yao Xiaonan

Journal of China & Foreign Highway

In order to better prevent tunnel concrete from cracking，the development law of concrete temperature and strain was studied.Based on the connection project of Sanjiang Middle Road in the Smart New City of Quzhou，a data acquisition system was established to monitor concrete temperature and strain on site.The defects of the traditional method that the temperature and strain monitoring are insensitive，and the monitoring data is discontinuous were overcome.In addition，the high-performance double grating temperature-strain sensor was used to simultaneously monitor the temperature and strain at the same position，and the temperature compensation method was used to overcome the influence of the ambient temperature on …

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 …

Research On General Drawing Design Technologies For Cover Culverts In Hunan Province, Peng Xiaoming, Li Yukun, Hu Qiong, Xia Yutao

Journal of China & Foreign Highway

As one of the main structures of highways，a culvert has the characteristics of large quantity and wide range.Affected by design and construction factors，engineering diseases of culverts have been prominent for a long time.With the extensive promotion of the green highway construction concept and the continuous updating of technical standards and design specifications，the original general drawing of culverts fails to meet the needs of the sustainable and healthy development of highway construction under the new situation.Hunan Provincial Communications Planning，Survey & Design Institute has conducted extensive and in-depth investigation and research on the key technologies of highway culvert design and prepared a …

Transverse Deformation And Countermeasures Of Cantilever Assembly Of Super‑Wide Steel Box Girder Of Zhongshan Bridge Over Shenzhen‑Zhongshan Link, Zhou Yu

Journal of China & Foreign Highway

In view of the transverse deformation of super-wide steel box girders of cable-stayed bridges during the cantilever assembly，the construction characteristics of the two-way eight-lane super-wide steel box girder of Zhongshan Bridge over Shenzhen-Zhongshan Link were analyzed，and the main causes of the transverse deformation during the cantilever assembly of the super-wide steel box girder were investigated.According to the matching height difference adjustment technology in the cantilever assembly construction of the wide box girder in China and abroad，this paper innovatively proposed a matching process of straight beam locking + initial tension of hanging cables，which better solved the problem of poor transverse deformation …

Fume Emission And Environmental Impact Assessment In Fresh Asphalt Tunnel Construction Site, Deng Wenti, Zou Guilian, Zhang Yuan, Yu Liang, Xie Huiduan

Journal of China & Foreign Highway

In view of the random monitori ng of fum e emission in asphalt pavement construction sites，combined with the engineering application of fresh asphalt in the construction of hot-mixed and hot-spread asphalt pavement in large and long tunnels for fume emission reduction，the fume collection and evaluation method of asphalt pavement construction sites were studied，and the emission reduction effect of fresh asphalt was evaluated.The Summa tanks were used to collect the asphalt fume at different positions of the paver，and the asphalt fume was quantitatively analyzed by gas chromatograph-mass spectrometer （GC-MS）.The results show that compared with the non-fresh asphalt from the same source，the …

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

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 …

Rotating Wheel Tracking Tester And Torsional Resistance Of Asphalt Mixtures, Yao Hongru, Wang Qiang, Lu Guangyan, Zhou Xiaolong

Journal of China & Foreign Highway

Asphalt pavement is prone to pla stic deformation and aggregate raveling when it is in torsion.At present，there is no standard test method and equipment to evaluate the torsional resistance of asphalt mixtures.In order to study the effective evaluation method for the torsional shear resistance of asphalt mixtures，this paper introduced the structures and working principles of three kinds of equipment developed in Japan.The torsional resistance of five typical asphalt mixtures was evaluated by rotating wheel tracking tests，and factors affecting the torsional resistance of asphalt mixtures were analyzed.The results show that the types of structures and binders of asphalt mixtures have an …

Construction Of Carbon Emission Monitoring And Management System For Commercial Vehicles, Chang Zheng, Song Yan, Ji Meichen, Liu Yuqing, Wang Jing

Journal of China & Foreign Highway

To construct a comprehensive carbon emission monitoring and management system for commercial vehicles，firstly，this article described the background and significance of carbon emission monitoring and management of commercial vehicles and summarized the research in relevant fields in China and abroad.Then，this article expounded on the carbon emission monitoring system for commercial vehicles，which covered three major levels：monitoring target layer，monitoring implementation layer，and monitoring summary layer，so as to achieve comprehensive and accurate carbon emission monitoring.Finally，combined with the carbon emission monitoring data of commercial vehicles，this article put forward a carbon emission management system for commercial vehicles based on data information，including carbon emission data sharing and opening，data …

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 …

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

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 …

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 …

Performance Of Composite Modified Permeable Concrete With Nano‑Silicon And Polypropylene Fiber, Liu Benli, Zhang Peng, Shan Jingsong, Zhao Haijian, Su Benjun, Li Chao

Journal of China & Foreign Highway

In order to improve the comprehensive performance of permeable concrete，nano-silicon and polypropylene fiber were added to permeable concrete to study the performance of the composite modified permeable concrete.Firstly，the influence of single-doped nano-silicon on the performance of cement paste and permeable concrete was studied，and the content of nano-silicon and the optimal water-to-binder ratio were determined.On this basis，different proportions of polypropylene fiber were mixed，and the reasonable content of polypropylene fiber was determined.The results show that nano-silicon improves the porosity of permeable concrete and increases the optimal water-to-binder ratio.When the content of nano-silicon is 0.5%，and the water-to-binder ratio is 0.32，the compressive strength of …

Oxygen Diffusion Behavior In Asphalt Film Based On Molecular Dynamics Simulation, Zhang Yu, Li Zheng, Fang Long, Han Bo, Wang Weicheng, Mao Zigen, Liu Qi, Yu Bin

Journal of China & Foreign Highway

Asphalt aging is one of the most important concerns during the use of asphalt pavement.However，asphalt usually exists in the form of a film in the mixture.Oxygen diffusion is an important factor affecting asphalt aging.To investigate the oxygen diffusion behavior in asphalt film under different working conditions，an oxygen-asphalt-aggregate （OAA） model was developed in this study to simulate the state of the asphalt film on the aggregate surface under real conditions.Oxygen diffusion and asphalt component migration in the OAA model were investigated under different conditions of time，temperature，oxygen concentration，and aggregate type.The influence of each factor on the molecular behavior of the model was …

Force Analysis Of Open Web Triangular Area Of Ganxi Super Bridge During Construction, Sun Keqiang, Li Baifu, Xue Qilin

Journal of China & Foreign Highway

Ganxi Super Bridge is an open web continuous rigid frame bridge with a main span of 300 m，and the upper chord box girder in the open web triangular area adopts the post support of a few telescopic columns with the hanging basket for suspension casting.The lower chord box girder adopts the full cable-stayed buckle method with a hanging basket for suspension casting.To analyze the force characteristics of the temporary structural system in the triangular area during the construction process using this method，the force variation law during the construction process of the temporary structural system in the triangular area was summarized …

Value Of Effective Length Coefficient Of Pier Of Long‑Span Continuous Rigid Frame Bridge, Tang Like, Song Suidi, Zhang Yang

Journal of China & Foreign Highway

The effective length coefficient of a pier is a controlling factor affecting the safety and economic index of bridge structures.The values of the effective length coefficient of compression members in Chinese and foreign codes are basically similar，and they are only applicable to ideal boundary conditions.In practical application，it is necessary to make appropriate adjustments according to the specific structural form.In order to get the value closer to the actual situation of the structure，this paper analyzed the overall stability of the structure and investigated the influence laws of different factors on the effective length coefficient of the continuous rigid frame bridge in …

Calculation Of Slag Weight In Shield Construction Based On Compound Continuous Belt Conveyor, Zhou Biao, Ding Xiaobin, Sun Wenjian, Ren Xufeng

Journal of China & Foreign Highway

Based on the construction data of continuous belt conveyors in shield construction，this paper evaluates two common calculation methods of slag weight （slag weight calculation based on loosening coefficient and slag weight calculation based on external additives ） to accurately manage slag in shield construction.According to the law of slag discharged from each ring in shield construction，an improved slag weight estimation method in shield construction was proposed.The results show that there is a big error in the slag weight calculation based on the loosening coefficient.When slag weight calculation based on external additives is used，the calculated value is always smaller than the …

Comparative Study On Dynamic Effect Of Basic Longitudinal Section Alignment, Du Yongping, Wang Peng

Journal of China & Foreign Highway

To improve the alignment in the old road reconstruction project，stress analysis was carried out，and the alignment and smoothness parameters were used as the major variables in the dynamic equation.A “human-vehicle-road ” dynamic analysis model was established，and alignment comparison groups were set，with only one group set with easing vertical curves.The Newmark- β method was used for programming and calculating the dynamic effects generated by the basic alignment with a radius of 7 000 m.The vibration indicators such as peak acceleration，root mean square of acceleration，vibration period，and frequency were used to analyze the dynamic effects of the basic alignment group.By analyzing the causes …