Chemical Engineering Commons^™

Effects Of Ferrite And Graphite Phases On Scratch Characteristics Of Nodular Cast Iron, Zhitong Xu, Ming Liu, Chenghui Gao, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

In this work, we conduct micro-scratch tests of nodular cast iron with Vickers indenter under constant normal load and investigate the effects of individual phases (i.e., ferrite and graphite phases) on the scratch charac- teristics of nodular cast iron. Using a bimodal Gaussian model to fit the experimental data of penetration depth, residual depth, elastic recovery rate, and scratch hardness, we calculate the contribution percentages of indi- vidual phases to scratch variables. The scratch variables are independent of the scratch speed used in this work, while the penetration depth increases linearly with increasing the normal load. There exists a large …

A Mechanical Model For Stress Relaxation Of Polylactic Acid/Thermoplastic Polyurethane Blends, Yi-Sheng Jhao, Hao Ouyang, Chien-Chao Huang, Fuqian Yang, Sanboh Lee

Chemical and Materials Engineering Faculty Publications

Polylactic acid (PLA) is considered a promising biodegradable polymer alternative. Due to its high brittleness, composite materials made by melt blending thermoplastic polyurethane (TPU) with PLA can enhance the toughness of PLA. To understand the forced aging caused by stress relaxation in polymer materials, this study explains the stress relaxation experiments of PLA/TPU blends with different mass ratios under applied strain through mechanical model simulations. The Kelvin representation of the standard linear solid model (SLSM) is used to analyze the stress relaxation data of TPU/PLA blends, successfully explaining that the Young’s moduli (E1 and E2) of springs decrease with increasing …

Mechanical Property Simulations Of Ploybenzimidazole Membranes., Blake Alexander Clark

Electronic Theses and Dissertations

This work explores mechanical properties of membranes made of polybenzimidazole utilizing molecular simulations. These simulations researchers to narrow down polybenzimidazole membrane compositions to viable candidates. These simulations are quicker than current purely experimental methods. The increase in throughput would be achieved by eliminating compositions that have unfavorable mechanical properties through preliminary simulation work before moving onto experimental methods. Determining polybenzimidazole membranes’ mechanical properties experimentally would, therefore, allow for researchers to speed up research in areas such as fuel cells and electrolyzers that make use of polybenzimidazole membranes. This study uses Materials Studio and the COMPASS III forcefield to perform these …

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 …

Improving Static Cold Storage Life Of The Human Heart Before Transplant, Juan Sebastian Rodriguez Paez

Theses and Dissertations

Organ storage and transportation are critical steps for the success of organ transplantation. Static cold storage (SCS) of hearts for heart transplantation (HTx) remains the standard approach. However, SCS may involve damage to the tissue resulting from extended hypothermic preservation, potentially affecting organ viability. More over, the temperature distribution on and within the heart is unknown during heart transplantation. Therefore, there is an interest to study different stages of the heart transplantation process towards determining the 3D temperature distribution on and within the heart. There could be a possibility of having a hypothermic injury in different parts of the heart …

Synthesis Of Durable Zeolite 13x Insertion Coatings And Scaled-Up Experimental Demonstration For Co2 Capture, Daniel Jamil Hocheimy

Theses and Dissertations

Minimizing the energy requirement for capturing carbon dioxide (CO₂) from post-combustion sources is critical to efficient industrial decarbonization and subsequent mitigation of the effects of climate change. The current portfolio of CO₂ capture technologies includes absorption, membrane separation and packed bed adsorption, which suffer from high energy and temperature requirements, scalability, and location dependency issues. Adsorption-based systems could cater to these concerns; however, their current embodiments primarily use packed adsorbent bed design and electricity-driven vacuum pumps to regenerate them. While simple and easy to fabricate, these designs are not scalable and cannot use heat to regenerate them …

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 …

Sulfonated Ionomer Composite Membranes For Use In Vanadium Redox Flow Batteries, Xueting Wang

All Dissertations

While vanadium redox flow batteries (VRFBs) have garnered significant attention as a promising scalable energy storage technology, the current membrane material used in this technology, Nafion™, suffers from high cross mixing of vanadium ions in the liquid electrolytes, directly impacting battery performance properties such as the voltage and coulombic efficiencies, as well as resulting in a reduction in the overall battery lifetime. The use of ionomer nancomposites has proven to be one promising route of directly addressing the issue of high ion crossover, though the mechanism by which the nanoparticles act to reduce crossover remains in open question. Herein, the …

Modeling Sex-Specific Changes In Myocardial Fibrosis, Grace Martin

Chemical Engineering Undergraduate Honors Theses

Heart disease the leading cause of death for both men and women in the United States. Cardiac fibrosis, or accumulation of extracellular matrix proteins in the heart, can occur after a heart attack and increase the risk for further complications. Current treatments for heart disease do not include extracellular matrix regulators, partly due to the complicated signaling network responsible for the production of these proteins. By using a computational model of the signaling network in cardia fibroblasts, the relationship between particular molecules and downstream extracellular matrix production can be examined.

Biological sex is an important factor for cardiac health and …

Electrode Engineering For Enhanced Performance And Low-Cost Redox Flow Batteries, Abena Williams

All Dissertations

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Yeast Surface Display Of Multiple Heterologous Proteins Via Molecular And Biochemical Processing Techniques, Shadrach Ibinola

Graduate Theses and Dissertations

The arming of yeast cell wall, also known as yeast surface display, is an effective technology for expressing target proteins extracellularly. It has been shown to provide bioengineered yeast with qualities that are not known to native yeast such as the ability to survive harsh conditions including high pH and temperature, for example. Furthermore, this technique has been implemented for various applications which include, protein engineering, bioethanol production, bioremediation, vaccine construction, and antibody development. The major mechanisms of yeast surface display exploit agglutination, flocculation, or proteins with internal repeats as the means by which a target (protein) is covalently attached …

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 …

Algorithms For Structural Synthesis Of Control Systems For Dynamic Objects Under Conditions Of Unmeasurable Disturbances, Husan Zakirovich Igamberdiev, Uktam Farkhodovich Mamirov, Bunyod Mamurjon Ugli Buronov

Chemical Technology, Control and Management

The paper talks about ways to use inverse dynamic models to structure a control system for moving objects when disturbances are not measured. To solve the main problems that arise when implementing the inverse dynamic model method, methods for synthesizing inverse systems with given dynamic characteristics are used. The solution to this problem is obtained based on the theory that dynamic observers are invariant to unmeasured input influences. We broke down the matrix operator on the right into elementary orthogonal rotation matrices and on the left into permutation matrices to get a stable answer to the equation of the current …

Modernization Of Water Flow Measurement In Open Irrigation Systems Using The Slope-Area Method, R.M. Aliev, Djalilov Anvar

Chemical Technology, Control and Management

This article describes two methods for determining water flow in open irrigation systems: “speed - area” and “slope - area”. The authors considered the problem of its modernization using the existing method for determining water flow “slope - area” in open irrigation systems. The essence of the issue is the remote transfer of parameters necessary for calculating water flow in open irrigation systems and improving the means of their processing. In scientific studies conducted by the authors, the required hydraulic parameters were studied using the “slope - area” and “speed - area” water flow methods. Based on experimentally obtained data, …

Improving Technology For Producing Complex Fertilizer From Low-Grade Phosphorites Of The Central Kyzylkum, A.Zh. Allamuratova, A.U. Erkaev, A.M. Reimov, Saparbay Kazakhbaev, Dilshodbek Kurbiyazov

Chemical Technology, Control and Management

The methods of nitric acid processing of phosphate raw materials are analyzed. A technology has been developed for the nitric acid processing of phosphate raw materials into nitrogen-phosphorus fertilizer with the implementation of the process in a condensed pulp by adding sulfuric acid. A technology for producing complex fertilizers with a wide range of N:P₂O₅:K₂O ratios with improved physico-chemical parameters due to the introduction of various potassium salts into the process is proposed.

Artificial Neural Network Based Grain Moisture Measuring Device, Erkin Eljaev, Shohrux Nurali O‘G‘Li Narzullayev, Elyor Faxriddinovich Khudoyberdiev

Chemical Technology, Control and Management

To date, the intellectualization of solving technical issues in managing, controlling, and measuring technological processes in all branches of industrial production is considered an urgent task. In this regard, a class of intelligent devices and sensors has emerged. Intelligent devices and sensors differ from their analog counterparts in that they have functions such as automatic adjustment of the measurement range, self-calibration, data processing, and decision-making. The article discusses the development of intelligent measuring instruments based on a capacitive transducer for measuring the moisture content of grain and grain products.

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, …

Sediment Characteristics And Hydrocarbon Composition Of Makukwa Seep In Southern Tanzania: Potential Implications For Subterranean Hydrocarbon Accumulation, Makungu M. Madirisha

Tanzania Journal of Engineering and Technology (TJET)

Exploring the interplay between natural seeps and nearby sediment and hydrocarbon properties is key to unlocking subsurface hydrocarbon potential. This study presents findings on the hydrocarbon composition and sediment characteristics of the Makukwa seep in southern Tanzania, providing insight into subterranean hydrocarbon accumulation. Sediment analysis across areas A and B, located approximately 20 m apart, showed a decrease in porosity with depth, indicative of typical sandstone formations. Area A, near the seeps, exhibited porosity ranging from 23% to 36%, whereas Area B, further away, showed porosity ranging from 22% to 38%. This suggests that a lower cretaceous sandstone layer may …

Production Of Biofertilizer From Fruit And Garden Waste, Neema Msuya

Tanzania Journal of Engineering and Technology (TJET)

The project focused on the production of bio-fertilizer from fruit and garden waste, with a specific emphasis on utilizing pineapple tops in the composting process. The objective was to produce and assess the properties of the bio fertilizer obtained from this process and evaluate its potential application in agriculture. In this study, the composting process was done in a 0.7 m long, 0.85 wide and 1.1 m high vessel, and 0.238 m3 pineapple top wastes, resulting in 0.35 m3 of biofertilizer. The bio fertilizer produced exhibited favorable characteristics, including a moisture content of 36%, pH of 7.1, and a total …

Assessment Of Risk Factors Related To Body Pain Complaints In Tanzania Construction Industry, Fatma K. Mohamed

Tanzania Journal of Engineering and Technology (TJET)

The construction industry is associated with risks that can result in musculoskeletal diseases. Although young male workers who are presumed to be healthy dominate the industry in Tanzania, body pain complaints have been widely reported. The aim of this study is to assess the prevalence and causes of body pains in workers. A cross-sectional study involving 396 workers was conducted. A chi square test was used for testing association of independent categorical variables and binary logistic regression analysis was used to determine predictors for body pain complaints. The results show that all study participants complained of at least one form …