Engineering Commons^™

Effective Nanomembranes From Chitosan/Pva Blend Decorated Graphene Oxide With Gum Rosin And Silver Nanoparticles For Removal Of Heavy Metals And Microbes From Water Resources, Mohamed Morsy

Nanotechnology Research Centre

No abstract provided.

Flexural Wave Manipulation By Non-Hermitian Planar Elastic Metasurface, Katerina Stojanoska

Theses and Dissertations

It has been demonstrated that metasurfaces with spatially asymmetric inner geometry exhibit unidirectional scattering effects, which can be used to control waves in a directional fashion. In this thesis, a planar Non-Hermitian elastic metasurface exhibiting unidirectional focusing of flexural waves is proposed. Asymmetrically loaded piezoelectric disks and metallic blocks comprise the unit cells. By using a negative capacitance shunting, a tunable material loss is embedded into the system. With suitable engineering of the induced loss profile, resonating building blocks are designed, which are capable of independently accessing unidirectional zero reflection. A planar metasurface is then created so that constructive interference …

Enhanced Throughput Of Aligned Polyacrylonitrile Nanofiber Manufacturing Via High-Speed Centrifugal Spinning, Jason Glen Ippolito

Theses and Dissertations

Centrifugal spinning is noteworthy due to its high fiber throughput rate compared to other nanofiber manufacturing platforms. It is capable of producing fibers in the nanoscale diameter range from a multitude of polymers, such as polyacrylonitrile (PAN). With a traditional centrifugal spinner, fiber can be rapidly spun and collected on static posts. However, the use of static posts inevitably forms a dense ring of fiber after a short period of time, and this fiber build up can halt the spinning process. In this work, the factors that influence the throughput and scalability of highly aligned centrifugally spun PAN fibers are …

The Neighborhood As An Energy-Generating Community The Case Of El-Banafseg Residential Neighborhood, East Cairo, Mona Helmy, Amany Micheal

Architectural Engineering

No abstract provided.

Effect Of Cr And Ni Concentrations On Resilience Of Cast Nb-Alloyed Heat Resistant Austenitic Steels At Extreme High Temperatures, Simon N. Lekakh, Mario F. Buchely, Mei Li, Larry Godlewski

Materials Science and Engineering Faculty Research & Creative Works

Austenitic Cr–Ni Alloyed Heat Resistant Steels with Nb Additions Are Used for Intensively Thermo-Mechanically Loaded Cast Components Working in Extreme High Temperature Oxidizing Environment. their Performance during Static Oxidation and Transient Thermo-Mechanical Loading Was Investigated to Recommend an Optimal Cost-Effective Cr/Ni Composition of Nb-Alloyed Austenitic Class Steels. the Static Oxidation and Transient Thermo-Mechanical Behavior of Three Austenitic Steels with Different Cr/Ni Alloying Levels Were Investigated and Compared for Variety of Working Conditions. Static Oxidation Was Performed between 900 °C and 1000 °C in Air for 400 H. the Critical Temperature Which Increases Spallation during Static Oxidation Was Determined for Each …

Method Of Evanescently Coupling Whispering Gallery Mode Optical Resonators Using Liquids, Hengky Chandrahalim, Kyle T. Bodily

AFIT Patents

The present invention relates to evanescently coupling whispering gallery mode optical resonators having a liquid coupling as well as methods of making and using same. The aforementioned evanescently coupling whispering gallery mode optical resonators having a liquid couplings provide increased tunability and sensing selectivity over current same. The aforementioned. Applicants’ method of making evanescent-wave coupled optical resonators can be achieved while having coupling gap dimensions that can be fabricated using standard photolithography. Thus economic, rapid, and mass production of coupled WGM resonators-based lasers, sensors, and signal processors for a broad range of applications can be realized.

Confined Growth Of Perovskite Stabilized By Strain Engineering, Xucheng Tao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Halide perovskite has been extensively studied for its excellent optoelectronic properties. In this project, we want to explore some range of band gap that conventional 2D materials could not have. To overcome this challenge, we aimed to produce two-dimensional (2D) perovskites with large scale which is suitable for device fabrication and improve its stability using strain engineering. To prepare such 2D perovskite, we tried 2D transformation first and then decided to use confined growth to optimize result. For strain engineering, we employed sputtered nickel as an external stressor.

So far, we have produced multilayer polycrystalline perovskites material close to atomic …

Piezoelectric And Conductive Polymer Based Flexible Devices Enabling Cardiovascular Health Sensing And Energy Harvesting, Andrew Closson

Dartmouth College Ph.D Dissertations

Piezoelectric materials show great promise for low-power wearable and implantable sensing, but their rigidity makes it challenging to integrate them with biological tissue. To address this, researchers have started exploring polymer-based functional materials that offer flexibility and are suitable for interfacing with the human body. However, these materials are still in their early stages, and a framework is necessary to illustrate how these materials, in conjunction with novel fabrication techniques and device designs, can enable the development of multi-functional sensing and energy harvesting devices.

This thesis utilizes highly scalable fabrication methods for functional polymers to build and test a flexible …

A Prediction Of Young's Modulus For Tin Containing Phosphate Glasses Using Quantitative Structural Information, Tatsuki Shimizu, Akira Saitoh, Uwe Hoppe, Grégory Tricot, Richard K. Brow

Materials Science and Engineering Faculty Research & Creative Works

A Rigid Unit Packing Fraction (RUPF) Model Was Used to Better Understand the Influence of Local Structural Units on the Young's Elastic Modulus (E) of Binary and Ternary Tin Phosphate Glasses. Quantitative Analyses of the Units that Constitute the Glass Structure, Obtained from X-Ray/neutron Diffraction and 31P MAS-NMR Spectroscopy, Were Used to Calculate Polyhedral Packing Fractions that, with Tabulated Bond Dissociation Energies, Were Used to Predict E based on a Modification of the Makashima-Mackenzie Relationship, Which Uses Ion Sizes to Calculate Packing Fractions. Predictions based on the RUPF Model Are Better Than Those based on Ion Sizes, and Extending the …

Evaluating The Potential Of Geopolymer Concrete As A Sustainable Alternative For Thin White-Topping Pavement, Sathvik S. Chandra, Pshtiwan Shakor, Sarwar Mohmmad, Bankole O. Awuzie, Atul K. Singh, Abishek Rauniyar, M Karakouzian

Civil and Environmental Engineering and Construction Faculty Research

Introduction:

The construction industry uses a large quantity of natural materials in the production of concrete. Although attempts to incorporate green materials in concrete began years ago, not every building uses such materials today, and roadways, particularly, still rely on unsustainable materials.

Methods:

Therefore, this study used alternative materials, including fly ash, manufactured sand aggregates, and different molarities of alkaline activators, to incorporate waste byproducts in a geopolymer concrete white-topping pavement layer. Recent developments have led to the emergence of geopolymers as distinct classes of materials. In the 1990s, fly ash-based geopolymers became more popular than other kinds, as they …

Two-Dimensional Field Effect Transistor, Yimeng Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

As silicon-based field-effect transistors (FETs) approach their physical limits with channel lengths approaching 5 nm, the search for new semiconductor materials that can surpass this limit has become urgent. Two-dimensional layered semiconductor nanomaterials, represented by graphene, have emerged as promising candidates due to their unique physical, mechanical, and chemical properties. Unlike traditional silicon-based FETs, two dimensional (2D) layered nanomaterials are held together by van der Waals forces between layers, with no dangling bonds on the material surface, which can effectively address the short-channel effect issue faced by traditional silicon-based FETs. However, unlike traditional silicon-based FETs, which have matured fabrication systems, …

Memristive Behavior And Its Applications In Different Materials., Mingyang Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

The huge amount of data calculation requires the next generation non-volatile memory (NVM) technology to have the characteristics of large storage capacity and fast read/write speed. The storage and computing are separated in the traditional von Neumann architecture-based hardware platforms. The data transport between information processing and storage are causing increasing time latency, which is called von Neumann Bottleneck. Memristor, as a basic circuit component, could combine perception, storage, and computing in a single component, which has a very wide range of application prospectives. In this paper, we investigate binary oxide memristor and 2D material memristor, including their structural design …

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 …