Materials Science and Engineering Commons^™

Machine Learning Based Prediction Models For Silicon Heterojunction Solar Cell Optimization, Rahul Jaiswal

Electrical and Computer Engineering ETDs

Silicon heterojunction solar cell of Heterojunction with Thin Intrinsic Layer (HIT) structure is a commercially available technology, and its market share will significantly increase by the next decade. With such a significant market share, any minor improvement in the device’s overall efficiency can be beneficial three folds - customer return on investment, industry revenue, and the overall carbon footprint (from manufacturing to recycling/ disposing of the device). Conventionally, device optimization for solar cells has been achieved using a hit & trial approach where multiple experiments are done to evaluate the best process conditions and device parameters. This approach has some …

Synthesis And Characterization Of Sodium Cathode Materials, He Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

As sodium batteries hold great promise as a next-generation energy storage device to replace lithium batteries, the development of sodium battery materials has become increasingly urgent. The current study aims to investigate two potential sodium-ion battery cathode materials, Sodium Vanadium Phosphate, and Sodium Manganese Hexacyanoferrate, optimize the experimental procedures, conduct a systematic analysis of material properties and characterization, and ultimately determine the ideal synthesis conditions for these materials.

In the first part of the study, we focused on optimizing the synthesis of Sodium Vanadium Phosphate. By investigating various synthesis conditions, such as annealing temperature, pressure, ascorbic acid content, and material …

Study Of A Carbon Fiber Reinforced Polymer Composite Using A Biobased Polyurethane As A Thermosetting Resin, Teddy Mageto

Electronic Theses & Dissertations

Carbon Fiber Reinforced Polymer composites (CFRP) have garnered increasing interest in recent years especially in the aerospace and automobile industries where they are gradually replacing metals as structural materials. This is owing to their light weight, high strength, high modulus, and excellent strength-to-weight ratio. Polymers are typically used as thermosetting resins in these composites. However, the synthesis of polymers currently is conducted via petrochemical processes which leads to adverse effects on the environment. To this end, in this work a biobased Polyurethane (PU) was used as a thermosetting resin in a CFRP. The biobased PU was synthesized by the reaction …

Synthesis And Characterization Of Polyaniline-Based High-Performance Carbon For Energy Storage Applications, Udeshika Kangane Arachchige

Electronic Theses & Dissertations

With the increase in global population, the demand for the energy required for daily activities including household necessities, electronic and electric devices, etc. enhances at an alarming proportion. Under these circumstances, supercapacitors (SCs) have attracted great attention as electrochemical energy storage devices. Nowadays, most commercially available supercapacitors are composed of metallic compounds. Due to the high consumption, and limited availability of these elements, it is necessary to find an alternative, effective, low-cost materials in place of using it. With the purpose of achieving high electrochemical performance, this research work focuses on developing carbon derived from polyaniline (PANI) as an efficient …

Development Of Novel Sensor Coating Methodology To Enable Understanding Of Fouling Mechanisms On Ion Exchange Membranes, Andrew Ulmer

Honors Theses

As populations expand and natural water resources are depleted, severe droughts and limited access to clean water have become an increased threat to areas across the world. Effective and economic water treatment methods such as electrodialysis (ED) are vital for combating these threats, especially in developing nations and secluded locations. Organic foulant adsorption on the surface of ion exchange membranes severely limits the capabilities of water desalination systems such as ED along with significantly increasing maintenance costs. Understanding characteristics such as the total amount and rate at which these foulants at specific concentrations adsorb and desorb to the membranes is …

Integrating Steel Slag Aggregates Into Asphalt Paving By Harmonizing Availability, Quality, Economics, And The Environment, Timothy R. Murphy

Theses and Dissertations

This thesis provides guidance on how to balance matters related to the environmental stewardship, market sources, origin and uses, material properties, performance, and economic impact of using slag materials in pavements. The literature on this topic provides numerous references on the use of slag materials for specific applications, and this thesis aims to make use of those references along with other data from the author to describe slag materials from a holistic perspective and provide some suggestions for balancing several factors that impact optimal use of this resource within pavement structures. Discussion is given to the increased importance of recycling …

Introduction To Data-Driven Systems For Plastics And Composites Manufacturing, Saeed Farahani, Srikanth Pilla, Yun Zhang, Fausto Tucci

Mechanical Engineering Faculty Publications

Applications of high-performance plastics and composites have widely been expanded to various industries due to their superior properties, such as high strength-to-weight ratio, chemical resistance, and thermal/electrical insulation. However, the numerous possible combinations of polymers and reinforcements/fillers, the variability of these materials, and their complex manufacturing processes pose challenges in terms of efficiently developing new plastics and composites, accurately modeling their properties, and effectively monitoring and controlling their manufacturing processes. Integrating data-driven techniques, such as machine learning, artificial intelligence, and big data analytics, is a promising pathway to overcome these challenges as it is demonstrated by the state-of-the-art research works …

Research And Application Of Dynamic Compaction Treatment Method For Highway Subgrade In Karst Development Area, Liu Xiaoming, Wang Yigang, Zhao Minghua

Journal of China & Foreign Highway

This paper utilizes discrete-continuum coupled numerical simulation to investigate the failure modes of karst cave roofs with varying spans under specific compaction energy levels. The relationship between the span of the cave roof and the compaction energy required to cause roof collapse is established, providing an estimation method for the maximum unsupported span of cave roofs within the subgrade area. Based on this, the stability of karst cave foundations under the influence of subgrade loads can be evaluated. Depending on the results, a double-layer reinforced continuous concrete slab can be installed in the pavement base to enhance stability and mitigate …

Comparative Analysis Of Asphalt Pavement Performance Prediction Models Based On Gamma And Markov Processes, Ma Shibin, Chen Yonghao

Journal of China & Foreign Highway

Pavement performance prediction is a critical component of pavement management systems, serving as an essential basis and prerequisite for decision-making in asphalt pavement maintenance. This paper introduces the relevant theories of Gamma and Markov stochastic processes to construct asphalt pavement performance prediction models and address uncertainties related to pavement degradation. The results show that stochastic process models are effective in predicting pavement performance degradation and service life. Matlab programming was used to predict asphalt pavement performance and lifespan, yielding pavement degradation curves that significantly improve prediction accuracy and reliability. Finally, taking a test road section in Hebei Province as an …

Study On Interlayer Bonding Properties And Influence Factors Of Cape Seal, Li Yan, Zhang Chengxue, Qiu Yeji, Zhang Haijun

Journal of China & Foreign Highway

To address pavement issues such as shoving and rutting caused by insufficient bonding strength in cape seal layers, this paper investigates the interlayer bonding properties and influencing factors of cape seal. Mechanical tests were conducted using a pavement interlayer shear-pull testing device. Through interlayer pull-off, direct shear, and torsional shear tests, the maximum tensile force, shear force, and torque at failure were obtained. The interlayer bonding performance of cape seal was analyzed in terms of gravel coverage rates, as well as upper and lower layer combinations. The results show that when the gravel coverage rate is 80%-90%, and the cape …

Fracture Mechanics‐Based Fatigue Study Of Corrugated Steel Webs, Li Haidi, Yang Lei

Journal of China & Foreign Highway

To develop fatigue analysis and evaluation methods for corrugated steel web structures, constant-amplitude fatigue load tests were conducted on experimental beam models, supplemented by fatigue test data from domestic and international studies. The finite element submodeling method was employed to obtain stress distribution functions at structural details, and the weight function method was used to derive the stress intensity factor at the crack tip. The Paris law in fracture mechanics was applied to derive the S-N curve for corrugated steel web structures. Comparative analysis with fatigue test results shows that when the initial crack depth is set as a0=t/20 (accounting …

Research On Multi‐Source And Heterogeneous Data Integration Of Large Bridge Health Monitoring System, Wang Daijun, Zhou Tiantu, Fu Junmin, Chen Xing, Lu Shuai, Yu Zheng

Journal of China & Foreign Highway

Large bridge health monitoring systems are characterized by numerous sensors, diverse types, various communication methods, and flexible network configurations. The multi-source heterogeneous nature of the data poses significant challenges for data integration. To address the application requirements of bridge health monitoring, this paper designs a multi-source heterogeneous data integration scheme. The scheme achieves structured storage of multi-source heterogeneous data and introduces the concept of “structured communication.” This enables structured communication configuration, unified communication control, and flexible data processing, standardizing and simplifying communication configuration management in data acquisition systems. These improvements enhance code simplicity, maintainability, and the overall integration level of …

Selection And Design Of Anchorage For Suspension Bridge In Downhill Area Under Complex Geological Conditions, Chen Yongliang, He Shiyong, Xia Zhixian, Wu Wenxiang

Journal of China & Foreign Highway

Due to the complexities of design and construction, long-span single-tower suspension bridges are rarely applied in practice. The main bridge of the Jinsha River Bridge at Tiger Leaping Gorge adopts a 766 m single-span single-tower steel truss suspension bridge. On the Lijiang anchorage side, complex geological conditions posed significant challenges due to geological structures, while the reservoir level of the planned hydropower station created adverse hydrological conditions for waterproofing and durability of the anchorage system. The selection of an appropriate anchorage type was therefore particularly challenging. This paper first details the selection process for anchorage under complex geological conditions. It …

Study On Countermeasures And Genetic Analysis Of Sloping Bridge Pile Hole Wall Failure, Yang Hua, Yin Xiaotao

Journal of China & Foreign Highway

The stability of slopes and the safety of bridge piles are interdependent, and ensuring the safety of sloping terrain is crucial for the safe construction of bridge piles. Based on three collapsed pile sections of the Huadizhai No. 2 Bridge, this paper utilized geological surveys to design initial terrain and altered terrain slope stability calculation conditions, along with horizontal compensation force calculation conditions under a safety standard of 1.35. By integrating geological analysis, slope stability assessment, and compensation force evaluations, the causes of pile hole collapse and corresponding countermeasures were analyzed. The results show that under the initial terrain, the …

Research On Gas Migration And Ventilation Disaster Prevention In Highway Tunnel, Wang Zhongqi, Lin Zhi, Feng Sen, Yang Hongyun, Chen Xiang, Liu Jiang

Journal of China & Foreign Highway

To understand the gas migration patterns and ventilation disaster prevention techniques during tunnel construction, this paper uses a real tunnel as the engineering context. A 3D transient ventilation physical model was established using Ansys Fluent, and the effects of ventilation on gas concentration were analyzed in combination with on-site monitoring data. The results show that the uneven diffusion of gas and airflow is prominent. Gas concentration and wind speed stabilize at a distance of 120 m from the tunnel face as ventilation time increases. During gas monitoring and prevention, special attention should be paid to the area between the tunnel …

Research On Influence Factors And Efficiency Analysis Of Expressway Maintenance Marketization, Zhong Wen, He Shoukui, Wang Xiaodong

Journal of China & Foreign Highway

To promote market-oriented reform of highway maintenance, this paper investigates its influencing factors and outcomes and proposes an evaluation model for assessing its effects. A panoramic analysis method within a three-dimensional framework was employed to determine the evaluation content. Drawing on the balanced scorecard concept, the analysis incorporates four dimensions: business, user, internal management, and learning and growth, with the innovative addition of a social responsibility dimension to construct an evaluation indicator system. Subsequently, a cloud-based extension model was developed to evaluate the effectiveness of expressway maintenance marketization and calculate the evaluation grade. Empirical analysis was conducted using data from …

Study On The Minimum Radius Of Vertical Curve Of Highway Main Line Entrance Section Based On Merging Sight Distance, Li Yang, Zhao Yemei, Chen Tianxing

Journal of China & Foreign Highway

Given the limited research on the vertical curve radius of highway mainline entrance sections and the lack of differentiation between entrance and exit sections in existing studies, this paper identifies merging sight distance as the primary influencing factor for the vertical curve radius of entrance sections. Using merging sight distance as the control condition, the vertical curve radius of entrance sections was studied. A safety merging sight distance calculation model for highway mainline entrance sections was established by analyzing the traffic behavior characteristics of vehicles on the entrance mainline and considering drivers’ psychological and physiological characteristics. The sight distance model …

Inspection And Evaluation Of Load‐Bearing Capacity Of Hollow‐Box Arch Bridge, Song Zegang, Yang Min

Journal of China & Foreign Highway

The inspection and evaluation of the load-bearing capacity of in-service bridges are crucial for ensuring structural and operational safety. This paper investigates a 90 m span hollow-box arch bridge, assessing its damage condition, material properties, and state parameters to determine partial evaluation coefficients. The bridge’s ultimate limit state and serviceability limit state load-bearing capacities of the main arch ring were then evaluated using both the original design standards and the current code. The results show that, compared to the original design standards, the safety factor for the compressive load-bearing capacity of the main arch ring cross-section is significantly reduced when …

Application Research And Prospect Of Passive Battered Pile, Zhou Dequan, Wang Chuangye, Zhou Yi, Zhao Yadang

Journal of China & Foreign Highway

Battered piles oriented in specific directions demonstrate superior horizontal load-bearing capacity compared to vertical piles. However, the working mechanism of battered piles remains inadequately understood, and corresponding design standards are yet to be established. These limitations hinder the effective utilization and application of the horizontal load-bearing and stability potential of battered piles. This paper comprehensively analyzes the soil-pile interaction mechanisms, horizontal displacement, and load-bearing behavior of passive battered piles and their composite systems under lateral unloading and lateral loading conditions, using model tests, numerical simulations, and theoretical analysis. In addition, it proposes future research directions aimed at advancing the study …

Study On Applicability Of Flexible Gabion Revetment In Soft Soil Subgrade In Lake District, Su Weiwei, Lei Mingxuan, Liu Guotian, Zhang Liujun, Liu Junyong

Journal of China & Foreign Highway

Based on FLAC3D finite difference software, this paper conducts numerical simulations of both flexible gabion revetment structures and rigid revetment structures to compare their deformation and stress characteristics. The results indicate that the flexible gabion revetment structure demonstrates excellent applicability for soft soil subgrades in lake districts. Compared with rigid revetment structures, the gabion revetment structure improves overturning stability through coordinated deformation within the foundation. It significantly reduces the basal stress, thus lowering the bearing capacity requirements for the foundation, and ensures a more uniform stress distribution at the base, minimizing differential settlement and enhancing foundation stability. Moreover, the gabion …

Study On Supporting Effect Of Pre‐Stressed Rock Bolts On Tunnel Face, Shen Xiangqian, Chen Daoyun, Zheng Chao

Journal of China & Foreign Highway

Focusing on the stability issues of the tunnel face in the large deformation section of soft rock in the Muzhailing Tunnel on the Weiyuan-Wudu Expressway, this paper proposes a technical solution for temporary reinforcement of the tunnel face using pre-stressed rock bolts. Numerical simulations were conducted to evaluate the reinforcement effect and effective range of pre-stressed rock bolts on the tunnel face, and the influence of initial ground stress on the reinforcement effect was further analyzed. The results show that under the given engineering conditions, pre-stressed rock bolts demonstrate significantly better reinforcement effects on the tunnel face compared to fully …

Study On Health State Evaluation Method Of Highway Tunnel Based On Neutrosophic Theory, Deng Fayou, Xia Caichu, Xu Chongbang

Journal of China & Foreign Highway

The structural complexity and inherent uncertainties of highway tunnels necessitate comprehensive consideration of various uncertain factors to reasonably evaluate their health state. By introducing neutrosophic theory, which accounts for structural uncertainties, this paper proposes a health state evaluation method for highway tunnels based on neutrosophic cosine and tangent similarity measures. The proposed method was applied to evaluate the health state of 10 samples. A comparison between the actual evaluation grades and the results obtained using the proposed method shows that the evaluation results are consistent with the actual grades. This indicates that the proposed method effectively addresses uncertainties in the …

Interlayer Bonding Performance Of Wtr/Apao Composite Modified Asphalt, Ji Hongyan, Yan Kezhen, Yuan Jian, Zhang Xuanyu

Journal of China & Foreign Highway

To investigate the bonding performance of waste tire rubber (WTR)/ amorphous α-olefin copolymer (APAO) composite modified asphalt as a waterproof bonding layer in asphalt pavements on cement concrete bridges, shear and pull-off tests were conducted. The shear strength and pull-off strength of SBS-modified asphalt, WTR-modified asphalt, and WTR/APAO composite modified asphalt were compared under different application rates and temperatures. The results show that WTR/APAO composite modified asphalt exhibits the best bonding performance, followed by WTR-modified asphalt, with SBS-modified asphalt performing the worst. Based on the shear and pull-off strengths at different temperatures, the optimal application rates were determined as 1.7 …

Optimization Study On Indoor Vibratory Compaction Curves Of Cement Stabilized Macadam, Qiu Youqiang, Zhang Liujun

Journal of China & Foreign Highway

To obtain well-defined secondary convex vibratory compaction curves and reduce the need for supplemental compaction point tests, this paper uses vibratory compaction tests for cement stabilized macadam in laboratory settings. Tests were conducted for two pavement sections along National Highway 110 (Hohhot to Bikeqi), exploring the influence of predefined moisture content intervals on vibratory compaction curves under varying cement dosages. The vibratory compaction curves were also compared with heavy compaction curves for analysis. The results show that the vibratory compaction curve is significantly influenced by the predefined moisture content intervals and cement dosage. For a moisture content interval of 1%, …

Study On Treatment Of Karst Foundation By Dynamic Compaction, Lyu Jiang, Zhao Hui, Yang Biao

Journal of China & Foreign Highway

Dynamic compaction is a commonly used method for treating karst foundations with cavities; however, the design parameters of dynamic compaction under different working conditions lack clear standards. This paper employs the finite element software Abaqus to simulate the effects of surrounding rock quality and karst roof thickness on the stability of karst cave roofs during dynamic compaction treatment. The results indicate that the vertical displacement and maximum tensile stress of karst cave roofs are negatively correlated with roof thickness. For Grade II and III surrounding rocks with better properties, no cave collapse occurred after dynamic compaction treatment. In contrast, for …

Research On Road Crack Recognition Model Based On Yolo V3 Deep Learning Algorithm, Su Weiguo, Wang Jingxiao

Journal of China & Foreign Highway

To address the challenges of manual intervention in road crack detection and the inaccuracy of traditional recognition algorithms, this paper proposes a road crack recognition method based on the YOLO v3 deep learning algorithm. The dataset images were first resized to 416×416 pixels. Labelme was then used to annotate cracks in the images and convert the boundary box location information. Finally, the YOLO v3 algorithm framework was employed for model training. The results show that the YOLO v3 algorithm achieves precision, recall, and F1 scores above 95%, with an image detection speed of 0.123 seconds per image. The YOLO v3 …

Discussion On Formula Of Off‐Load Increase Coefficient Of Single‐Box Multi‐Cell Wide Girder, Gao Qingfei, Wang Renzhi, Li Jun, Guo Binqiang, Qin Weijun

Journal of China & Foreign Highway

Single-box multi-cell wide girders are widely applied in highway and urban bridges due to their excellent integrity and large width, especially with increasing traffic volumes. However, existing methods for calculating the off-load increase coefficient of single-box multi-cell wide girders are either too complex or fail to meet engineering needs, limiting their applicability in preliminary design. This paper explores eight influencing factors of the off-load increase coefficient, calculates the coefficients using the transverse frame method, and proposes an empirical formula for the off-load increase coefficient. The proposed formula is validated using the Xiushui Street Wide Girder Bridge in Jilin City.

Study On Modification Of Phosphate Pretreated Aggregate Vegetation Porous Concrete, Li Zhengxing, Hou Zebiao

Journal of China & Foreign Highway

To enhance the interfacial structure between aggregates and cementitious materials in vegetation porous concrete and improve its compressive strength, this paper investigates the effects of phosphate pretreatment on aggregate properties and the corresponding compressive strength of vegetation porous concrete. The performance of untreated aggregates, water-washed aggregates, and acid-treated aggregates was evaluated, and the modification mechanism was explored from the perspective of the interfacial transition zone (ITZ) using scanning electron microscopy (SEM). The results show that phosphate effectively removes impurities from the aggregate surface and increases surface roughness, thus improving the compactness and stability of the ITZ. After soaking the aggregates …

Experimental Study On Water Stability Of Sand Compound Modified Mud Road, Chai Ruixiang, Wu Kai, Ye Wei, Cui Jinmei, Wang Jicheng, Li Zhantao

Journal of China & Foreign Highway

Sand compound modified mud, as a coupled medium of sand and soil, differs from traditional modified mud. To further investigate its water stability indicators, orthogonal design was employed to conduct indoor water stability simulation tests (surface infiltration test, underground capillary water test, and dry-wet cycle test) on sand compound modified mud. The water stability of the modified mud was characterized using the change rate of unconfined compressive strength (UCS). The results show that the unconfined compressive strength and water stability of the modified mud were significantly improved. Under different water disturbance conditions, the order of influence of factors such as …

Soil Respiration Measurements Reveal High Retention Of Organic Carbon From Corn Residue Derived High-Lignin Fermentation Byproduct Enabling Sustainable Lignocellulosic Biofuel Production, Michelle Sun Wang

Dartmouth College Master’s Theses

While 2G biofuel production can utilize non-edible, lignocellulosic feedstocks such as agricultural residues to produce liquid fuel, harvesting crop residues is unsustainable without careful management of the soil underneath. By harvesting a fraction of the crop residues left in the field after harvest, soil health can diminish and critically, the soil organic carbon (SOC) stored in agricultural fields can decrease. Currently, in the most popular 2G process models published, the issue of soil degradation remains unresolved with residue harvest strategies receiving considerable attention in the literature and other SOC management strategies receiving far less. Specifically, the strategy of returning the …