Engineering Commons^™

Studies On The Synthesis, Reactivity, And Stability Of Au Nanoparticles In Ts-1 Zeolites For Propylene Epoxidation Within H2/O2 Mixtures, Weixin Li

Dissertations - ALL

The increasing global demand for energy and materials has highlighted the importance of efficient production of chemical intermediates like propylene oxide (PO), a key compound in manufacturing polyurethanes, propylene glycol, and other industrial products. Traditional methods, such as the chlorohydrin process and organic peroxide methods, pose environmental and economic challenges due to hazardous by-products and complex processes. The need for greener alternatives led to the exploration of gold (Au) catalysts for the direct catalytic epoxidation of propylene using hydrogen (H2) and oxygen (O2). This research focused on understanding the propylene epoxidation process over Au catalysts, specifically Au nanoparticles (AuNPs) supported …

Wood-Plastic Composites Integration For Triboelectric Nanogenerator Electricity Generation, Hanbyeol Park, Razamala Yashna F. Dimaporo, Sophia Maureen A. Emperado, Anton Jefferson L. Pangilinan, Juan Carlo T. Gumangan

Sinaya: A Philippine Journal for Senior High School Teachers and Students

Access to electricity in underdeveloped communities is particularly crucial in improving the living standards of people and alleviating poverty by promoting sustainable development. This study deals with the exploration of incorporating wood-plastic composite (WPC) – specifically wood pulp (W) and high-density polyethylene (H) – into triboelectric nanogenerator (TENG) flooring system to convert mechanical energy to electrical energy, promoting sustainable energy, reducing greenhouse gas emissions, improving the quality of life, and serving as feasible flooring tiles. Two types of TENG tiles were prepared by using different WPC ratios: 30W:70H and 70W:30H. A static bending test was conducted to assess the flexural …

Harmonic Impedance Modeling And Oscillation Analysis Of Modular Multilevel Converter, Yuhong Wang, Wensheng Chen, Shilin Gao, Jianquan Liao, Yangfan Cheng

Journal of System Simulation

Abstract: To facilitate rapid analysis of the oscillation stability mechanism in modular multilevel converter-based high voltage direct current (MMC-HVDC) systems and streamline the simulation process for determining MMC impedance characteristics, a simplified mathematical simulation model for MMC closed-loop impedance is developed using the harmonic state space method. This model considers various control strategies and includes both AC-side and DC-side impedance models. By applying a Nyquist criterion-based impedance analysis method, the stability mechanisms on the AC and DC sides of the MMC are examined. In addition, a data-driven oscillation stability analysis method is also proposed, leveraging a global sensitivity algorithm based …

Optimal Operation Scheduling Of Integrated Energy System Considering Energy Priority, Dongli Jia, Keyan Liu, Zhaoying Ren, Zezhou Wang, Dongsheng Tang

Journal of System Simulation

Abstract: Integrated with the actual situation of power grid and the growth of new energy, a multiobjective model for optimal scheduling of the integrated energy system(IES) is established based on the analysis of the energy-flow relationship of the IES and taking into account the priority of energy utilization and the load demand response in terms of the mismatch between the distributed energy sources and the loads, the net benefit of the unit cost of the IES, and the load response degree. Combined with the equipment and the environmental benefits system, a priority constraint for energy utilization has been established for …

Research On Scheduling Strategies Simulation For Building Air-Conditioning Systems Based On Transfer Imitation Learning, Qiaochu Wang, Yan Ding, Chuanzhi Liang, Haozheng Zhang, Chen Huang

Journal of System Simulation

Abstract: To solve the problem of unstable performance and inefficient training process of low-quality data conditions at the initial stage of online deployment of air conditioner scheduling, we propose a migration-imitation learning-based air conditioning scheduling strategy simulation method. Reinforcement learning methods are used to generate building operation strategies. A standard building simulation model serves as the source domain, upon which migration learning is applied. An imitation learning loss function is incorporated into the intelligent loss function to enhance algorithm performance. The results indicate that, compared with the non-use of migration learning, the proposed method can improve the operational efficiency by …

Behavioral Modeling Of Manned-Unmanned Cooperative Air Combat Based On Improved Abc Algorithm, Peng Wang, Haoyu Liu, Ni Li, Zexi Yu, Shangjie Jia

Journal of System Simulation

Abstract: To solve the problem of difficulty in establishing collaborative behavior models and weak adversarial capabilities in typical MAV/UAV air combat scenarios, a mixed decision based MAV/UAV behavior modeling framework is proposed. Using collaborative rule sets, rule subsets, tactical action sets, and other tools, a hierarchical decision collaborative behavior model supporting five types of collaborative tactics, including grinding tactics and unilateral flanking tactics, is constructed in this framework. a behavior model parameter optimization method based on an improved artificial bee colony (ABC) algorithm is proposed. By using the Mason rotation method to initialize the population, a better initial honey source …

Path Planning Of Desert Robot Based On Deep Reinforcement Learning, Ming Li, Wangzhong Ye, Jiehua Yan

Journal of System Simulation

Abstract: Due to the complexity and variability of the desert environment, the key to the high-efficient of mobile robot is how to avoid obstacles and plan its path. To solve the problems of poor search efficiency and slow convergence of deep reinforcement learning algorithm in complex environment, an improved deep reinforcement learning path planning algorithm is proposed. The exploration factor is improved and dynamically adjusted according to the convergence degree of the algorithm, so that the exploration factor dynamically decreases with the increase of the understanding degree of the agent to the environment, thus speeding up the convergence speed of …

Effects Of Negative Poisson’S Ratio On The Mechanics Of Auxetic Carbon Fiber Composites Under Tensile, Buckling And Low Velocity Impact, Wenhua Lin

Dissertations - ALL

Carbon fiber reinforced polymer (CFRP) matrix composites exhibited superior properties, such as high specific stiffness and specific strength, excellent fatigue and corrosion resistance, and low coefficient of thermal expansion, have been popular across various industries including aerospace, marine, automotive, energy, civil infrastructure, and high-end sports over the past decades. However, one significant drawback of CFRP composites is the susceptibility to low velocity impact damage which, for aircraft, can be results of tool drop, runway debris, and bird strike during takeoff and landing. These impact events could lead to external and internal damages of a CFRP composite structure in various damage …

Thermodynamics And Shear Flow Dynamics Of Block Copolymer Morphologies In Solution, Senyuan Liu

Dissertations - ALL

Block copolymers (BCPs) have been a focal point of research for several decades. They have been engineered to produce various morphologies by altering the combinations of chemically distinct polymer segments that interact selectively with their environment, such as in aqueous or organic solvents, or within a polymer matrix. The ability to tailor morphological features by manipulating polymer chain length, composition, and monomer chemistry has led to applications in advanced material manufacturing, catalysis, emulsification, environmental remediation, targeted drug delivery, gene therapy, and medical diagnostics. Consequently, understanding the relationship between copolymer architecture and the self-assembled morphologies at equilibrium, the pathways of structure …

Pan-Cancer Analysis Of Rna Dysregulation, Somatic Mutations, And Matrix Stiffness Using Bioinformatics Approaches, Gongyu Tang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Cancer is a complex disease driven by genetic mutations, epigenetic modifications, and alterations in the tumor microenvironment. Understanding these intricate molecular mechanisms is crucial for advancing cancer diagnosis, prognosis, and treatment. RNA sequencing (RNA-seq) has emerged as a powerful tool to study cancer by providing comprehensive insights into gene expression, alternative splicing, and mutations at the transcriptome level. This dissertation leverages RNA-seq data to explore different dimensions of cancer biology through multi-omics integration and computational approaches. The research is divided into three main projects. First, I developed OncoDB, an interactive database to analyze gene expression, methylation patterns, and viral interactions …

Mems 411: Dbf Wind Tunnel, Jeremy Choh, Stefan Hester, David Howard, Yang Yang

Mechanical Engineering Design Project Class

Design, Build, Fly (DBF) is a student-run engineering team at Washington University in St. Louis (WUSTL) that designs aircraft for flight competitions. Before assembling the final product, DBF runs numerous simulations on prototypes to understand the effects of drag and lift on the designed shape. The lift and drag parameters are important to aircraft design, as DBF hopes to optimize flight performance during competitions. However, simulations require computational power, are theoretical at best, and may inaccurately represent real-life situations. Preferably, DBF can use physical testing that captures prototype performance with more qualitative details.

Senior Design Group Z approaches DBF's needs …

Tensile Strain Validation Of Welded Wire Reinforcement, Alvaro Montes

Theses and Dissertations

There have been historical concerns regarding the ductility of welded wire reinforcement (WWR). Recent changes in ACI 318-19 now require all grades of A615 and Grade 100 A706 nonprestressed steel reinforcement to have a ratio of tensile strength to yield strength greater than 1.10 and 1.17 respectively. Although this code requirement does not currently apply to WWR, this preemptive study investigated the current state of the art of WWR manufactured in North America in preparation for such a possibility. This project included the tensile-testing of approximately 365 WWR material specimens of various cross-sectional sizes to determine the ratio of tensile-to-yield …

Enhancing Concrete Sustainability With Self-Healing Technologies, Al Shimaa Abdullatif

Theses and Dissertations

Thanks to its strength, durability and affordability, Portland cement concrete is the most commonly used building material worldwide. However, concrete cracking is inevitable due to numerous factors including shrinkage, exposure to external chemicals, internals reactions, excessive loads, to name but a few. Self-healing is a promising technique that can enable concrete to autogenously heal cracks and alleviate much of the damage. Such healing can without a doubt extend the service life with less need for external repair works therefore it contributes to sustainability. Over the years, several means of self-healing agents have been explored including bio-based procedures and the incorporation …

Post-Processing National Water Model Long-Range Forecasts With Random Forest Regression In The Cloud To Improve Forecast Accuracy For Decision-Makers And Water Managers, Jacob Matthew Anderson

Theses and Dissertations

Post-processing bias correction of streamflow forecasts can be useful in the hydrologic modeling workflow to fine-tune forecasts for operations, water management, and decision-making. Hydrologic model runoff simulations include errors, uncertainties, and biases, leading to less accuracy and precision for applications in real-world scenarios. We used random forest regression to correct biases and errors in streamflow predictions from the U.S. National Water Model (NWM) long-range streamflow forecasts, considering U.S. Geological Survey (USGS) gauge station measurements as a proxy for true streamflow. We used other features in model training, including watershed characteristics, time fraction of year, and lagged streamflow values, to help …

Local Food System Planning On Multiple Governance Scales: A Grounded Theory Analysis, Decker Ure

Theses and Dissertations

Local food systems (LFS) comprise the people, policies, infrastructure and practices of food production, distribution, and consumption in localized areas. LFS are becoming an increasingly important part of urban sustainable development and have recently gained significant traction in the urban planning and sustainable community spheres. Worldwide shocks to global food systems such as the COVID-19 pandemic and the Ukraine-Russia war have further elevated global interest in LFS, bringing local food to the forefront of many communities as they try to insulate themselves and their food supply from future risk. However, despite this growing interest in and policy momentum for local …

Harnessing Extrinsic Dissipation To Enhance The Toughness Of Composites And Composite Joints: A State-Of-The-Art Review Of Recent Advances, Gilles Lubineau, Marco Alfano, Ran Tao, Ahmed Wagih, Arief Yudhanto, Xiaole Li, Khaled Almuhammadi, Mjed Hashem, Ping Hu, Hassan A. Mahmoud, Fatih Oz

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Interfaces play a critical role in modern structures, where integrating multiple materials and components is essential to achieve specific functions. Enhancing the mechanical performance of these interfaces, particularly their resistance to delamination, is essential to enable extremely lightweight designs and improve energy efficiency. Improving toughness (or increasing energy dissipation during delamination) has traditionally involved modifying materials to navigate the well-known strength-toughness trade-off. However, a more effective strategy involves promoting non-local or extrinsic energy dissipation. This approach encompasses complex degradation phenomena that extend beyond the crack tip, such as long-range bridging, crack fragmentation, and ligament formation. This work explores this innovative …

Balancing Sustainability Goals And Treatment Efficacy For Pfas Removal From Water, Md Moshiur Rahman Tushar, Zaki Alam Pushan, Nirupam Aich, Stetson Rowles

Civil Engineering & Construction: Faculty Publications

Per- and polyfluoroalkyl substances (PFAS) are emerging water contaminants with significant environmental and health impacts, posing challenges in water treatment due to their high stability and persistence. With increasing regulations, a critical need remains in understanding the sustainability of PFAS treatment technologies. Our review examines the environmental, economic, and social impacts of current PFAS treatment technologies across different water types and contexts. Additionally, we propose a framework for future sustainability studies to enable more holistic technology evaluations under specific conditions.

The Coalition Development Of Allied Close Air Support Doctrine During World War Ii, David S. Stieghan

Doctoral Dissertations and Projects

This research aims to discover how the American and British air forces worked collaboratively to provide ground support to their armies in Europe during World War II. While the official histories and scholars of the two countries concentrate on their unique national efforts, they analyze little of their cooperative efforts. By examining primary and secondary research sources to discover the experiments, doctrine development, and combat experience of both air forces, an understanding emerges that both nations combined their efforts in World War II in separate directions until beginning to work together on planning for the D-Day invasion.

By discovering the …

Kinetic Modeling Of Bacteria Removal From Suspensions By Magnetic Nanoparticle Capture And Magnetic Separation, Bowen J. Houser

Theses and Dissertations

This thesis investigates the kinetic modeling of bacteria removal from suspensions using magnetic nanoparticle (MNP) capture and magnetic separation. Functionalized magnetic nanoparticles, especially those coated with polydopamine (pDA), were employed to bind with various bacterial species in phosphate-buffered saline (PBS), apple juice, whole blood, and its components. By analyzing the capture efficiency and kinetics of capture across different bacterial species and mediums, we developed mathematical models describing the capture kinetics of bacteria by the pDA-MNPs. Experimental results demonstrated that pDA-coated MNPs achieved high capture efficiency with certain Gram-positive species like Staphylococcus aureus, and one Gram-negative species, Neisseria perflava; however, capture …

A Computational And Mathematical Approach To The Preclinical Development Of Alpha Emitting Radiopharmaceutical Therapies, Abdulaziz Said

McKelvey School of Engineering Graduate Student Theses & Dissertations

Numerous candidate nuclides have been undergoing rigorous preclinical development in the pursuit of novel targeted therapies. Successful development of these drugs relies on the understanding of physiological impacts at the macro and micro scales, in addition to a scalable process for their production. Here, mathematical and computerized approaches have been developed to guide this preclinical development. In this report, two alpha emitting nuclides Pb-212 and Ra-223 are modeled. Radium-223 dichloride citrate a newly approved ion indicated for treatment of bone metastatic castrate resistant prostate cancer, irradiates lesions through targeted uptake in bone at sites of disease. We have undertaken the …

Safety And Optimality Monitors For Learning-Enabled Systems Using Conformal Prediction, Jackson Cox

McKelvey School of Engineering Graduate Student Theses & Dissertations

The use of machine learning to create data-driven plant models and controllers has led to an increased need for safety and optimality monitors for model-based systems. System plant models are subject to uncertainty due to learning constraints such as unseen data and overfitting or physical constraints such as unknown dynamics and noise. This uncertainty is detrimental to safety-critical systems and must be properly regulated. To curb this uncertainty, we create prediction sets using the guarantees provided by Conformal Prediction. With a user-specified high probability, these prediction sets contain the true plant system states for an entire prediction horizon, which we …

Pyrophosphate-Free Glycolysis In Clostridium Thermocellum Increases Both Thermodynamic Driving Force And Ethanol Titers, Bishal Dev Sharma, Shuen Hon, Eashant Thusoo, David M. Stevenson, Daniel Amador-Noguez, Adam M. Guss, Lee R. Lynd, Daniel G. Olson

Dartmouth Scholarship

Background

Clostridium thermocellum is a promising candidate for production of cellulosic biofuels, however, its final product titer is too low for commercial application, and this may be due to thermodynamic limitations in glycolysis. Previous studies in this organism have revealed a metabolic bottleneck at the phosphofructokinase (PFK) reaction in glycolysis. In the wild-type organism, this reaction uses pyrophosphate (PPi) as an energy cofactor, which is thermodynamically less favorable compared to reactions that use ATP as a cofactor. Previously we showed that replacing the PPi-linked PFK reaction with an ATP-linked reaction increased the thermodynamic driving force of glycolysis, but only had …

Beyond The Surface: Understanding Temperature Polarisation In Dcmd Membranes Through Varied Operational Parameters, Hiras Ahamed Hijaz, Masoumeh Zargar, Abdellah Shafieian, Amir Razmjou, Mehdi Khiadani

Research outputs 2022 to 2026

Conventionally, a single Temperature Polarisation Coefficient (TPC) value is calculated to quantify Temperature Polarisation (TP). In this research, the extent of polarisation is investigated by capturing temperature profiles at specific points along a MD membrane using miniature thermocouples, eliminating the need for TPC calculations. The extent of polarisation at a point is affected by two contributory factors, namely the proximity of flow inlets and the difference in vapour pressure across the membrane at that point. Under this direction, this work examined the influence of permeate temperature, feed salinity, and flow direction on the development of the temperature profiles. Our analysis …

Kinetics Model Of Cananga (Cananga Odorata) Fresh Flower Extraction Using Microwave Hydrodistillation Method, Darnengsih Darnengsih, Hikmatun Ni’Mah, Mahfud Mahfud, Ayu Chandra Kartika Fitri

Makara Journal of Science

Recent studies have focused on improving essential oil extraction methods by incorporating advanced technologies, such as microwave-assisted hydrodistillation (MHD). Despite these advancements, further research is necessary to fully understand how different kinetic models influence extraction efficiency. This study evaluates several kinetic models for extracting essential oil from fresh Cananga flowers using MHD, examining how varying microwave power affects extraction rates and correlates with kinetic model parameters. The extraction process involved introducing 200 grams of fresh Cananga flowers in 400 mL of distilled water and subjecting the mixture to microwave power levels of 200 W, 400 W, and 600 W. The …

Optimization Of Construction Scheme Of Ultra‑Large Special‑Shaped Foundation Pit Adjacent To Existing Station And Temporary Steel Bridge, Chen Dengwei

Journal of China & Foreign Highway

With the intensifying development density of urban underground space in China，the impact of ultra-large foundation pit construction on the normal operation of adjacent structures cannot be ignored.Relying on the Huangmugang Comprehensive Transportation Hub Project in Shenzhen，this paper studied the deformation of the envelope structure and soil caused by the excavation of the ultra-large special-shaped foundation pit，as well as the structural response of the deformation of the adjacent existing station and the temporary steel bridge.The paper optimized the construction scheme of the special-shaped foundation pit excavation.The results show that the deformation trend of the envelope structure on the north and south …

Friction‑ 1d Transformer ： A 1d Vision Transformer Hybrid Model For Skid Resistance Prediction On Asphalt Pavements, Pei Feifei, Nie Zilong, Xu G Uomin, Zhan You, Gong Xianqi, Ai Changfa, Deng Yuan, Ji Zhengyun, Wang Shifa

Journal of China & Foreign Highway

The friction performance of road surfaces is an important indicator of highway safety，which is closely related to road texture.In this paper，a set of three-dimensional denoising methods for road texture data with different noise levels was proposed，which could effectively remove noise while preserving local texture features.In addition，a skid resistance prediction model named Friction- 1D Transformer was developed based on the design concept of Vision Transformer （VIT） for skid resistance evaluation of asphalt pavements.Unlike traditional convolutional neural networks，the Friction- 1D Transformer utilized positional encoding structures and multi-head attention mechanisms to extract global features from one-dimensional （1D） texture signals along the direction of …

Phosphorus Adsorption Capacity Of Volcanic Scoria, Easton Jeffrey Perkins

Theses and Dissertations

Phosphorus (P) pollution in stormwater runoff poses a significant threat to water quality, contributing to eutrophication and ecosystem degradation. This research evaluates the potential of volcanic scoria (VSco), an abundant and cost-effective resource in Utah, USA, to influence P concentrations in urban stormwater systems. Batch adsorption experiments examined the behavior of VSco across three particle sizes—fine (<0.841 mm), medium (0.841–2 mm), and granular (2.38–9.5 mm)—under conditions mimicking stormwater scenarios. The results reveal that fine VSco exhibited higher adsorption efficiency than medium and granular sizes, achieving notable P removal at higher concentrations. However, at lower concentrations, fine VSco showed potential for P release due to desorption of pre-existing P. Medium and granular VSco showed minimal adsorption capacity and, in some cases, acted as P sources, highlighting a dual potential depending on stormwater conditions. Adsorption isotherms indicate that the adsorption behavior of fine VSco aligns with the Langmuir model, with a finite and relatively low adsorption capacity. Calculated distribution coefficient (Kd) values for fine VSco ranged from 0.04 to 0.005 L/g, indicating weak adsorption efficiency compared to materials like activated carbon (1–10 L/g) or soils with moderate adsorption capacity (0.1–0.5 L/g). Loss-on-ignition tests confirmed that VSco’s performance is driven by its physical and chemical properties, particularly its calcium content, rather than organic matter. The study emphasizes caution in applying fine VSco for stormwater remediation due to its potential to release P under typical runoff conditions. However, fine VSco may still be viable in specific scenarios where P levels are higher, such as in stormwater hotspots or localized areas with elevated concentrations, allowing for targeted remediation. The research underscores the need for further testing to refine VSco’s applications, particularly in low-impact development (LID) practices, such as infiltration basins and rain gardens, to effectively manage P levels while supporting ecological and aesthetic goals. These findings contribute to understanding the complex role of VSco in urban stormwater systems, offering insights for sustainable water quality management and nutrient cycling in urban landscapes.

Developing A New Liquefaction Ejecta Prediction Model Considering Soil Properties Of Non-Liquifiable Surface Layers Using New Large Database From The 2012 Emilia Romagna, Italy Earthquakes, Jonah Bradley Dundas

Theses and Dissertations

The presence of a non-liquefied crust overlying a liquefied layer has been found to have a significant effect on sand ejecta and surficial liquefaction damage, as observed by Ishihara (1985). Following the 2010-2011 Canterbury seismic sequence in New Zealand, almost no foundation deformation occurred in areas with liquefaction susceptible soils overlain by at least a 3 meter thick crust [1]. In contrast, the 2012 Emilia-Romagna earthquake in Italy provided surface evidence of liquefaction despite 6+ meter thick crusts. Several researchers have proposed liquefaction prediction models [e.g. LPI [2], Ishihara Curves [3], LSN [4], LPIISH [5] and the methods proposed by …

Experimental Investigation On Shrinkage Effect Of Ultra‑High Performance Concrete Under Steam Curing, Li Bing, Yang Tengyu, Fang Changle, Luo Zirun, Li Chuanxi, Tan Ke

Journal of China & Foreign Highway

Determining the free shrinkage of U HPC is an important basis for analyzing the shrinkage effect of steel UHPC composite bridge deck.Therefore，based on the UHPC materials to be used in a project，three batches of UHPC free shrinkage specimens were made，and three specimens were made in each batch.By testing the strain and temperature of specimens during curing，the free shrinkage strain-age curve and temperature-age curve of UHPC were obtained.The development and variation law of UHPC shrinkage strain are discussed.Based on the experimental results，the equivalent time is introduced on the basis of Arrhenius empirical formula，and a modified model of free shrinkage is proposed.Finally，based …

Mechanical And Vegetative Performance Of Bamboo Fiber‑Reinforced Eco‑Concrete With Recycled Aggregate, Li Tao, Deng Bofan, He Maolin, Liu Ting, Chen Houde

Journal of China & Foreign Highway

In response to the current common urban construction waste disposal issue，this study utilized processed recycled construction waste aggregate and bamboo waste materials to produce bamboo fiber-reinforced eco-concrete with recycled aggregate.By adjusting the dosage of bamboo fiber，the effects of the dosage of bamboo fiber on the mechanical and vegetative performance of the concrete were systematically analyzed by means of orthogonal tests and verification methods.The test results indicate that bamboo fiber enhances the toughness of eco-concrete significantly.Particularly，when the dosage of bamboo fiber exceeds 3.0 kg/m3，there is a significant enhancement in the tensile performance of the eco-concrete with recycled aggregate.Due to the spatial …