Engineering Commons^™

Mesenchymal Stromal Cell Response To Degenerated Intervertebral Disc-Like Ph, Kyle Cannon

All Dissertations

Intervertebral disc degeneration (IVDD) has become increasingly prevalent and is a common contributing factor to low back pain. There are currently no clinical treatment options for IVDD that alleviate the symptoms of IVDD while simultaneously promoting repair of IVD tissue. One treatment option being explored is intradiscal administration of mesenchymal stromal cells (MSCs). However, the microenvironment of the degenerating IVD places significant stress on both native IVD cells and implanted cells. There are several questions that need to be addressed which may help further inform the development of efficacious intradiscal MSC therapies for IVDD. These questions include: 1) Do MSCs …

Novel Vector Assignment Approach For Inherent Strain Modeling Of Laser Powder Bed Fusion Manufacturing, Lucas M. Morand

All Dissertations

The expansion of the design space due to additive manufacturing (AM) has been a large motivator for the success of this family of processes. Despite the complexity of the physics in metal laser powder bed fusion AM causing significant stresses and strains in finished parts, the design advantages and subsequent performance improvements continue to drive the expansion of AM. Because the trial-and-error approach to AM part development is cost prohibitive, simulation of prints has become crucial. However, full thermo-mechanical simulation is susceptible to the same pitfall of time and computational cost in order to attain part-scale results. The development of …

A Computational Investigation Into Thermo-Kinetic Parameters Governing The Decomposition Of Bio-Oil Model Compounds, Ali Huseein Aljefri

Theses

Among notable products from thermal degradation of biomass are simple oxygen-containing aromatics. These compounds typically appear in high loads in collected bio-oil derived from biomass. As such, it is important to comprehend the decomposition chemistry of this category of compounds. This thesis takes on board a general approach to report thermo-kinetic parameters that govern decomposition of a selected set of bio-oil model compounds in two distinct systems: firstly radical-derived pathways in the gas phase and secondly thermal degradation in their condensed media. The first is attained through accurate density functional calculations while the second is accomplished through the use of …

Heat Sink Integrating Phase Change Materials (Pcms) For Cooling High Power Electronic Devices, Mohammad Sameer Qasem

Theses

This research explores the numerical analysis of phase change materials (PCMs) heat sinks, focusing on high heat flux dissipation applications, e.g. electronics cooling. Both 2D and 3D numerical models using gallium and paraffin RT31 as PCMs are considered within a heat sink design framework featuring a rectangular cavity and dual opposing vertical copper walls serving as fins to dissipate heat from the hot sink base that receives heat from the heat source. The inclusion of a Triply Periodic Minimal Surface (TPMS) ‘Primitive’ structure as an in-fill thermal conductivity enhancer (TCE) in the case of the gallium heat sink, and a …

Emulsion Stability, Rheological Properties, And Combustion Characteristics Of Water-Jojoba Biofuel Emulsion, Ihab Mohamed Helal

Theses

This thesis comprehensively investigates the stability, rheological properties, and engine performance implications of Water in Jojoba Biodiesel (WJBD) emulsion. The research delves into multiple aspects, including the influence of diverse surfactants and water concentrations on emulsion stability. It also yields valuable insights into the development of stable water in jojoba biodiesel emulsions, specifically tailored for diesel engines. These insights contribute significantly to the body of knowledge of positioning emulsion fuels as viable alternative to traditional diesel fuels. The anticipated benefits include notable reductions in emissions, improvement in combustion efficiency, and lower production cost. Importantly, this study underscores the critical importance …

Valorization Of Date Palm Waste For The Isolation, Characterization, And Surface Chemistry Modification Of Nanocellulose, Mohsin Raza

Dissertations

This dissertation focuses on the utilization of date palm waste, a lignocellulosic material, as a source for the extraction of nanocellulose (NC), a versatile biopolymer with applications in biodegradable composites, bioplastics, and food packaging. Conventional methods of NC production using mineral acids such as sulphuric and hydrochloric acid are reaching their limits of toxicity, so more environmentally friendly alternatives such as ionic liquids (ILs) are being explored. The research focuses on the characterization of different date palm wastes to evaluate their α−cellulose content, lignocellulosic character, and thermal stability. By comparing extraction methods with mineral acids and ILs, the study evaluates …

Retrofit Prioritization Of Substandard Buildings For Earthquake Risk Management, Roshen John Joseph

Dissertations

Despite the pressing need for risk mitigation techniques for reinforced concrete (RC) structures designed without considering seismic design provisions, limited research has focused on selecting experimentally verified retrofit measures from various alternatives, particularly considering minimizing disruption to operating real-life buildings. Against this backdrop, this study is directed toward selecting reliable and costeffective retrofit techniques for improving the seismic performance of substandard RC buildings with different structural systems and heights common in medium seismicity regions. Contemporary retrofit approaches are investigated, including polyparaphenylene benzobisoxazole fiber-reinforced cementitious matrix (P-FRCM) composites, carbon FRCM (C-FRCM) composites, thin high-performance reinforced concrete (HPRC) jackets, and self-centering energy …

An Adaptive Large Neighborhood Search For The Multi-Vehicle Profitable Tour Problem With Flexible Compartments And Mandatory Customers, Vincent F. Yu, Nabila Yuraisyah Salsabila, Aldy Gunawan, Anggun Nurfitriani Handoko

Research Collection School Of Computing and Information Systems

The home-refill delivery system is a business model that addresses the concerns of plastic waste and its impact on the environment. It allows customers to pick up their household goods at their doorsteps and refill them into their own containers. However, the difficulty in accessing customers’ locations and product consolidations are undeniable challenges. To overcome these issues, we introduce a new variant of the Profitable Tour Problem, named the multi-vehicle profitable tour problem with flexible compartments and mandatory customers (MVPTPFC-MC). The objective is to maximize the difference between the total collected profit and the traveling cost. We model the proposed …

Non-Vacuous Generalization Bounds For Adversarial Risk In Stochastic Neural Networks, Mustafa Waleed, Liznerski Philipp, Antoine Ledent, Wagner Dennis, Wang Puyu, Kloft Marius

Research Collection School Of Computing and Information Systems

Adversarial examples are manipulated samples used to deceive machine learning models, posing a serious threat in safety-critical applications. Existing safety certificates for machine learning models are limited to individual input examples, failing to capture generalization to unseen data. To address this limitation, we propose novel generalization bounds based on the PAC-Bayesian and randomized smoothing frameworks, providing certificates that predict the model’s performance and robustness on unseen test samples based solely on the training data. We present an effective procedure to train and compute the first non-vacuous generalization bounds for neural networks in adversarial settings. Experimental results on the widely recognized …

Enhanced Phosphogypsum Thermal Reduction By Carbon In Presence Of Sodium Chloride At High Temperature, Li Chao, An Xuebin, Jing Hu, Yixiao Wang, Shizhao Wang, Yunshan Wang, Gang Yang, Yong Sun

Research outputs 2022 to 2026

This paper reports an enhanced approach of thermal reduction of phosphogypsum (PG) in the presence of sodium chloride (NaCl) in its molten phase. The thermodynamic together with in-situ thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) result indicates the yield of CaS (solid) at the investigated temperature range (800–850 °C). Addition of NaCl not only appreciably reduces the activation energy of this reaction (800–850 °C) on average from 315 to 175 (kJ·mol−1) materially, but also significantly improve the conversion from CaSO4 to CaS. Additionally, the NaCl based waste salt (NaCl-WS) containing organic compounds (0.21 wt%) was found to produce similar results when compared …

Innovative Rate Design As A Free Market Solution To Climate, Resiliency, And Economic Challenges, Brendan J. Moore

LSU New Orleans Theses and Dissertations

A century-old problem of electricity rate design is cost-shifting between ratepayers (Wellinghoff, J. & Tong, J., 2015). A much newer cost-shifting example of great and increasing importance happens whenever ratepayer generated “renewable energy” is sold to the grid—all too often, this is accused of being unfairly rewarded (Ritchie, 2016). ProRate resolves both these concerns and ProRate can actually be derived simply from the premise of avoiding “all” cost shifts between ratepayers (Katz, CLEPm Rewards to Arrest Demand Cost-Shifting, 2019; Katz, CLEP5 Rewards to Arrest Energy Cost-Shifting, 2019). Another major problem with the Old Utility Model is the lack of price …

Primary Consolidation Settlement Of South Louisiana Clay Deposits In Marsh Environment, Alice E. Stark

LSU New Orleans Theses and Dissertations

Accurate estimation of primary consolidation of in-situ marsh soils is inherently difficult in south Louisiana due to the soft, settlement prone soils and variable alluvial material. To investigate the accuracy of settlement analysis methods commonly utilized in local practice, estimates from numerical models were compared to the results of a settlement monitoring program at a project site during construction. Sensitivity analyses were then performed using several parameters that were used in the settlement analysis, and the results were compared to the field observations.

The disagreement of observed settlement data and settlement estimates produced with a model that did not include …

Developing General Purpose Apps To Automate Image Analysis Of Wave-Augmented-Varicose-Explosion Atomization And Other Multi-Phase Interfacial Flows, Ethan Newkirk

Senior Honors Theses

Atomization involves disrupting a flow of contiguous liquid into small droplets ranging from one submicron to several hundred microns (micrometers) in diameter through the processes of exerting sufficient forces that disrupt the retaining surface tensions of the liquid. Understanding this phenomenon requires high-speed imaging from physical models or rigorous multiphase computational fluid dynamics models. We produce a MATLAB application that utilizes various methods of image analysis to quickly analyze and store mathematical data from detailed image analyses. We present a user with numerous tools and capabilities that provide results that deviate from 1.8% to 8.9% of the original image sequence …

Renewable Energy Misinformation: A Literature Based Approach To Rebutting False Claims, Matthew Ard

McNair Research Journal SJSU

No abstract provided.

Enzymatic Production Of Cyclodextrin Using Cyclodextrin Glycosyltransferase Immobilized In Metal Organic Frameworks (Mofs), Babatunde Azeez Ogunbadejo

Thesis/ Dissertation Defenses

Cyclodextrins (CDs) and their derivatives have attracted significant attention in the pharmaceutical, food, and textile industries, which has led to an increased demand for their production. CDs are typically produced by the action of cyclodextrin glycosyltransferase (CGTase) on starch. Owing to the relatively high cost of enzymes, the economic feasibility of the entire process strongly depends on the effective retention and recycling of CGTase in the reaction system, while maintaining the enzyme’s activity and stability. Previous supports used for this purpose have numerous drawbacks, including enzyme leaching, activity loss and significant mass transfer limitations. The aim of this dissertation was …

Semi-Annual Progress Report #14, Missouri University Of Science And Technology

Semi-Annual Progress Reports

No abstract provided.

Ultra-Sensitive Visible-Ir Range Fiber Based Plasmonic Sensor: A Finite-Element Analysis And Deep Learning Approach For Ri Prediction, Mohammad Al Mahfuz, Sumaiya Afroj, Afiquer Rahman, Md. Azad Hossain, Md. Anwar Hossain, Md Selim Habib

Electrical Engineering and Computer Science Faculty Publications

In this paper, a relatively simple and ultra-sensitive Photonic crystal fiber (PCF) based surface plasmon resonance (SPR) sensor is proposed for detecting different analyte refractive indices (RIs) ranging from 1.33 to 1.43 over a wide range of wavelength spectrum spanning 0.55 μm to 3.50 μm. The comprehensive finite-element simulations indicate that it is possible to achieve remarkable sensing performances such as wavelength sensitivity (WS) and figure of merit (FOM) as high as 123,000 nm/RIU and 683 RIU^-1, respectively, and extremely low value of wavelength resolution (WR) about 8.13×10⁻⁷ RIU. A novel artificial neural network (ANN) model is …

Multifidelity Comparison Of Supersonic Wave Drag Prediction Methods Using Axisymmetric Bodies †, Troy Abraham, David Lazzara, Douglas Hunsaker

Mechanical and Aerospace Engineering Student Publications and Presentations

Low-fidelity analytic and computational wave drag prediction methods assume linear aerodynamics and small perturbations to the flow. Hence, these methods are typically accurate for only very slender geometries. The present work assesses the accuracy of these methods relative to high-fidelity Euler, compressible computational-fluid-dynamics solutions for a set of axisymmetric geometries with varying radius-to-length ratios (R/L). Grid-resolution studies are included for all computational results to ensure grid-resolved results. Results show that the low-fidelity analytic and computational methods match the Euler CFD predictions to around a single drag count (~1.0 × 10^–4) for geometries with R/L ≤ 0.05 …

Experimental Analysis Study Wave Drift Force Of Moored Floating Production Units (Fpu), Arifin Rifliansah, Wibowo Harso Nugroho

Makara Journal of Technology

Drift forces caused by sea waves and currents are an important aspect that needs to be studied in planning moored floating structures, especially Floating Production Units (FPU) type ships which are operated for oil and gas exploration. This study describes the drift forces on the FPU which is subjected to environmental loads in the form of waves. The slow-drift movement that occurs in a moored FPU, and experiencing irregular waves is a very important problem. The complexity of determining drift forces analytically and numerically requires the use of hydrodynamics model test. In the model test on a certain model scale …

Great South Metals Processing Cost Optimization, Duy Nguyen, Pierce Morgan, Proma Dey, Rodrick Adams

Senior Design Project For Engineers

Great South Metals, a prominent service center in flat-rolled metal industry, undertook a strategic initiative to overhaul its pricing and operational strategies. The implementation of this project aimed at refining GSM's pricing matrix to accurately reflect processing costs for both GSM-owned and customer-owned materials. The project utilized a DMAIC approach, focusing on the integration of complex data sets with ERP systems and managing organizational change. Key strategies introduced include the Grandfather method, which respects longstanding customer relationships while transitioning them to new pricing structures, and Staggered Break Adjustments, which optimize machine operation and reduce downtime. The implementation of these strategies …

Thermogravimetric Analysis And Chemical Kinetics Of Waste Tires, Mahir Mohammed Said

Tanzania Journal of Engineering and Technology (TJET)

The focus of this paper is to analyse the pyrolysis reaction of waste tires. The pyrolysis was studied experimentally using thermal and chemical kinetics. The tires were pyrolyzed using thermogravimetry at a temperature range of 200 to 600°C, with heating rates of 10, 20, and 50°C/min. The activating energy was observed to increase with increased temperature. The highest activating energy was 101.02 kJ/mol at a heating rate of 50°C/min.

Enhanced Post Deposition Annealing Conditions On The Fabrication Of High Quality Thermochromic Vanadium Dioxide Films, Nuru R. Mlyuka

Tanzania Journal of Engineering and Technology (TJET)

Sputter deposition of thermochromic VO2 thin films for smart window applications has been faced with several challenges including the need for high deposition temperature, extremely precise and narrow range of oxygen/argon flow ratio and target poisoning during sputtering. Deposition of VO2 at room temperature without oxygen followed by post-deposition annealing has been cited as one of the potential mitigations to the challenge. In this study, the effects of post-deposition annealing conditions on the structural, electrical and optical properties of VO2 thin films are reported. The films were prepared on soda lime glass substrates using DC magnetron sputtering of metallic vanadium …

Causes And Consequences Of Inefficient Drilling And Blasting In Mine Development Headings: A Case Study Of Hard Rock Gold Mining Operations In Northern Tanzania, George Bennett

Tanzania Journal of Engineering and Technology (TJET)

Despite the introduction of the perimeter blasting technique at the Tulawaka Gold Mine, the mine continued to suffer from an overbreak of mine development headings, with an average overbreak of 24% every 22 m, which is approximately twice the acceptable 10% overbreak. The causes of this problem include ineffective drilling practices and uneven and excessive charging of explosives, resulting in a slightly high powder factor of 3.94 kg/m3 instead of 3.8 kg/m3, as per the design. The problem of overbreak resulted in ore dilution, a longer mine development cycle time and additional costs of approximately US$ 45 per cut, especially …

An Optimization Tool For A Standalone Photovoltaic System, Johanes Kasilima

Tanzania Journal of Engineering and Technology (TJET)

Stand-alone photovoltaic systems (SAPV) are often used in remote areas where access to grid electricity is limited. This system depends on solar energy. However, Photovoltaic (PV) systems need a greater initial investment than conventional sources of energy, and their effectiveness is reliant on a number of environmental conditions such as the unpredictable solar radiation. One step in reducing the investment cost of a PV system is determining the optimal size of solar PV components that minimize costs. This paper presents a Particle Swarm based optimization tool for sizing Stand-alone PV systems. The optimization tool selects the optimal Levelized Cost of …

Design And Optimization Of An Azeotropic Distillation Pilot Plant For The Production Of Pure Ethanol, Samwel V. Manyele

Tanzania Journal of Engineering and Technology (TJET)

This study aimed to design an azeotropic distillation plant using Aspen Plus® V10 software and determine optimal process conditions for producing pure ethanol greater than 95% from pre-concentrated near-azeotropic ethanol-water solution. The non-random two-liquid Redlich-Kwong thermodynamic model was the base method for property analysis and performance prediction. Modelling and simulation of the converged process were conducted for fixed column variables (R = 5, N = 12 and p = 1 atm). Plant operating parameters were varied in the range of 0 to 1 for the pre-heater vapour fraction, 2 to 10 for the column feed plates (NFP), 2 to 6 …

Optimization Pump As Turbine Coupled To A Self-Excited Induction Generator Using Multi-Objective Genetic Algorithm, Emanuel J. Nyirenda

Tanzania Journal of Engineering and Technology (TJET)

As a way of accelerating the deployment of affordable and clean renewable energy generation technologies, applying a pump working as a turbine coupled to a self-excited induction generator is gaining popularity in various areas including energy recovery and micro hydro systems. However, it is currently challenging to predict the performance of the PAT-SEIG system and there is no agreed-upon rule on the selection of the appropriate system to be installed at a particular site. This paper has presented multi-objective optimization to select the best operating point of the PAT-SEIG system. The results show that the peak efficiencies for the PAT …

Effect Of Zr And W Doping On Microstructures, Transition Temperature And Solar Transmittance Modulation Of Thermochromic W/Zr Co-Doped Vo2 Thin Films, Haji F. Haji

Tanzania Journal of Engineering and Technology (TJET)

Thermochromic W/Zr co-doped VO2-based thin films with different concentrations of Zr were successfully deposited on soda lime glass substrates by direct current (DC) magnetron sputtering of V(99)W(01) alloy and Zr targets at a substrate temperature of 425 °C. The films were characterized by x–ray diffraction (XRD), atomic force microscopy (AFM), Rutherford backscattering spectroscopy (RBS), two-point probe and UV/VIS/NIR spectroscopy. The film’s structural properties evolution was significantly influenced by Zr concentration in the films. The transition temperature and hysteresis loop widths of the films were found to decrease with increasing Zr concentration. For the Zr concentrations of 0.21 at.%, 0.23 at.% …

Evaluation Of Cybersecurity In Remote Working Settings For Mobile Network Operators, Victoria Mahabi

Tanzania Journal of Engineering and Technology (TJET)

Cybersecurity has increasingly been a primary concern to people as technology advances and allows them to work remotely. This study thus evaluated the cybersecurity posture for organisations that have opted for remote working culture, whereas emerging cyber threats, practices to combat them, and appropriate guidelines for managing cyber threats were discussed. The study used a descriptive design with a quantitative approach from 118 information technology personnel working for Tanzania's three major mobile network operators (MNOs). SPSS analysed the collected data. The study revealed that predominant cyber-threats affecting MNOs in remote working include human errors, phishing attacks, malicious domains, denial of …

Examining Mechanical Property Differences In Concrete With Natural And Synthetic Fiber Additives, Walid Fouad Edris, Sammy Elbialy, Ayman El-Zohairy, Ashraf Mohamed Soliman

Faculty Publications

The rapid growth of Natural Fiber Laminate (NFL) innovation is a direct response to environmental challenges, positioning these materials as superior alternatives to synthetic fiber composites. This paper delved into the outcomes of an extensive experimental study investigating the influence of sisal fiber (SLF), banana fiber (BF), and glass fiber (GF) on the mechanical and microstructural characteristics of concrete. The water absorption curves were established for sisal fiber concrete (SLFC), banana fiber concrete (BFC), and glass fiber concrete (GFC). Furthermore, Scanning Electron Microscope (SEM) observations were conducted to perform microanalysis and failure analysis of the tested specimens. The results revealed …

Sol-Gel Synthesis And Microstructure Characterization Of Nio-Tio2 Semiconductor, Godlisten N. Shao

Tanzania Journal of Engineering and Technology (TJET)

NiO-TiO2 is a fascinating p-n semiconducting binary metal oxide with unique electronic and optical properties. The NiO-TiO2 has been synthesized using complicated preparation methods and expensive precursors that hamper their large-scale production. The present study reports the preparation of NiO-TiO2 semiconductor with improved physicochemical properties. NiO-TiO2 samples were prepared through one-pot sol-gel synthesis process followed by sintering of the as-synthesized materials at temperatures ranging from 600 to 1000 °C. The role of thermal treatment and NiO content on the microstructures was exquisitely studied. The microstructure of the NiO-TiO2 samples was examined by Raman spectroscopy, XRD, XRF, SEM-EDAX, high resolution TEM, …