Engineering Commons^™

Contemporary Problems In Aerosol Aggregation And Gelation, Pai Liu

McKelvey School of Engineering Theses & Dissertations

Aggregation of nanoparticles in aerosols is a fundamental phenomenon with important implications to diverse fields ranging from material synthesis to pollutant control. The past few decades have witnessed extensive research on investigating the structure and growth mechanism of aerosol aggregates with sizes spanning across several orders of magnitude. This dissertation focuses on some contemporary problems that remain unaddressed in this topical area. Aerosol aggregates in sub-micron regimes, which are formed via the irreversible collision and aggregation of solid nanoparticle monomers, are fractal-like in their morphology. A mathematical description of this seemingly random structure dates to the seminal works by Forest …

Investigation Into The Thermodynamics And Kinetics Of The Binding Of Cu2+ And Pb2+ To Tis2 Nanoparticles Synthesized Using A Solvothermal Process, Jesus Cantu, John Valle, Kenneth Flores, Diego Gonzalez, Carolina Valdes, Jorge Lopez, Victoria Padilla, Mataz Alcoutlabi, Jason Parsons

Mechanical Engineering Faculty Publications and Presentations

In the present study, titanium (IV) sulfide (TiS2) was synthesized and investigated for the removal of Cu2+ and Pb2+ ions from aqueous solutions. TiS2 nanoparticles synthesized through a solvothermal synthesis were characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM). The average particle size for the TiS2 material was determined to be 8.03 ± 0.98 nm from the diffraction pattern. Studies were performed to examine the effects of pH, temperature, time, and interfering ions on the binding of Cu2+ and Pb2+ to the TiS2. As well isotherm studies were performed to determine the binding capacity of TiS2 for both …

The Researching Some Containig Rocks Of Uranium Ores By Method Of The Thermal Analysis, K. Sanakulov, M.A. Kurbanov, U.Z. Sharafutdinov

Gorniy vestnik Uzbekistana

The paper presents the results of comparative laboratorial testings physical and chemical properties ion-change resins: BD-706, BO – 020, BO-008, BD-709S, BD- 710M, А-560, А – 508, MS-2040. There are results present, that resins ВО-008, BD-709S, BD-710M and MS 2040 do not comply with requirements ОSТ 95.291-86. Kinet- ics of sorption uranium from sulphuric acid solution and carbonate solution presented, that resin А-560 has the best indexes.

Quantifying And Elucidating The Effect Of Co2 On The Thermodynamics, Kinetics And Charge Transport Of Aemfcs, Yiwei Zheng

Theses and Dissertations

Anion exchange membrane fuel cells (AEMFCs) have shown significant promise to provide clean, sustainable energy for grid and transportation applications – and at a lower theoretical cost than more established proton exchange membrane fuel cells (PEMFCs). Adding to the excitement around AEMFCs is the extremely high peak power that can now be obtained (> 3 W cm-2) and continuously improving durability (1000+ h), which has made the future deployment of AEMFCs in real-world applications a serious consideration. For some applications (e.g. automotive), the most critical remaining practical issue with AEMFCs is understanding and mitigating the effects of atmospheric CO2 (in …

Improving Boron For Combustion Applications, Kerri-Lee Annique Chintersingh

Dissertations

Boron has received much attention as a potential additive to explosives and propellants due to its high theoretical gravimetric and volumetric heating values. The challenge, however, is that boron particles tend to agglomerate, have lengthy ignition delays and very low combustion rates. Prior research indicates that boron’s long ignition delays are due to its inhibiting naturally occurring oxide layer, impeding the diffusion of reactants for oxidation. For combustion, current studies report that boron particles have two consecutive stages, but the actual reaction mechanism is poorly understood. Despite many years of relevant research, quantitative combustion data on micron-sized boron particles are …

Carboxylic Acid Hydrodeoxygenation Over Supported Noble Metal Catalysts, Joshua Gopeesingh

Dissertations - ALL

Carboxylic acid hydrodeoxygenation (HDO) over supported noble metal catalysts was carried out in order identify the main challenges associated with supported monometallic catalysts and identifying solutions that may increase the practicality of these high activity metals. Using propionic acid as a probe molecule, it was found that supported platinum (Pt) and ruthenium (Ru) catalysts have two main issues: selectivity and stability. Both metals are quite unselective towards HDO products, multiple chemistries occur over the catalysts that lead to a myriad of undesired products. Decarbonylation (DCN) is the most selective pathway over Pt catalysts, while both DCN and methanation chemistries are …

Influence Of Frictional Or Rotational Kinetic Energy On Wellbore-Fluid/Temperature Profiles During Drilling Operations, Ahmed Q. Al Saedi, Ralph E. Flori, C. Shah Kabir

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Temperature-profile distributions in a wellbore during drilling operations might take different forms when applying the energy balance in the overall system. For steady-state conditions, wherein the wellbore is considered a closed system, adding any source of additional energy to this system can influence the predicted temperature profiles. This study presents a new analytical model to investigate the influence of rotational energy arising from the drillstring operation on the wellbore-temperature behavior.

A significant part of the drilling operation is rotation of the drillstring. Depending on the drilling rig, various equipment provides this kind of energy, such as the rotary table or …

The Development Of A Viscoelastic Ellipsoidal Model For Use In Measuring Plantar Tissue Material Properties During Walking, Jessica Lee Deberardinis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: The mechanical characteristics of the plantar tissues during walking is not well understood as most of the current research focuses on testing specific plantar regions in cadavers or while the feet of the participants are raised. In this work, it is hypothesized that a viscoelastic geometric ellipsoid model used to assess multiple structures of the foot would be accurate and robust. This model would be participant-specific and applicable to the entire stance phase of gait.

Methods: The proposed viscoelastic ellipsoid model would represent several key anatomical areas: Heel, Posterior Midfoot, Anterior Midfoot, Metatarsals 1-2, Metatarsals 3-5, Toe 1, Toe …

Kinetic Analysis Of Biosolid Pyrolysis, William Regan Kreutter

Master's Theses (2009 -)

Waste reduction and energy recovery have been an environmental focus. Many of these solutions involve the thermal degradation of waste, such as household garbage or organic waste. To help reduce the negative environmental impact associated with processes like incineration, methods have been developed to utilize the carbonaceous material and energy contained in waste. Wastewater treatment plants are responsible for collecting and cleaning billions of gallons of sewage and stormwater each year. The water collected goes through multiple cleaning stages before being discharged into surface water. Sewage sludge, commonly referred to as biosolids, are produced during the process. Biosolids are carbon …

Design Of Shape-Morphing Structures Consisting Of Bistable Compliant Mechanisms, Rami Alfattani

USF Tampa Graduate Theses and Dissertations

This dissertation presents a design concept for shape-morphing structures that have two stable configurations. The design concept defines the methodology of transforming a planar structural shape into spatial structural shape using bistable compliant mechanisms. Bistable complaint mechanisms are used to achieve structural stable configurations. The dissertation incorporating geometrical relationships for the mechanisms that form the primary structure described in step-by-step process. This dissertation implements the design layouts for designer to creating shape-morphing structures including origami. The novel contribution of the work is classified in three models. The first model presents a methodology to induce bistability behavior into an origami reverse …

Leaching Characteristics Of Rare Earth Elements From Bituminous Coal-Based Sources, Xinbo Yang

Theses and Dissertations--Mining Engineering

The demand for rare earth elements (REEs) has increased over the last decade due to applications in high technology devices including those in the defense industry. The recovery of REEs from primary sources such as rare earth minerals are viable using physical separations followed by chemical processing. However, weak market values and environmental concerns have limited the viability of such operations. On the other hand, REE recovery from secondary sources such as apatite ore, bauxite waste, and waste recycling, provides an opportunity to take advantage of a resource that does not require mining costs as well as other associated costs …

Elucidation Of The Catalytic Partial Oxidation Of Methane Utilizing The One-Of-A-Kind Catalytic Shock Tube Technique, Robyn E. Smith

Dissertations and Theses

The mechanism for the catalytic partial oxidation of methane has been debated in scientific literature for over 20 years. This is a seemingly simple reaction producing CO, CO₂, H₂ and H₂O through either partial oxidation followed by complete oxidation or complete oxidation followed by reforming steps. What is happening when the reaction is allowed to occur in an environment absent of transport limitations, absent of temperature gradients and temperature changes, absent of boundary layers must be understood and, until now, has yet to be achieved in one experimental technique.

A novel method using a one …

Pyrolysis Kinetics Of Live And Dead Wildland Vegetation From The Southern United States, Elham Amini, Mohammad-Saeed Safdari, David R. Weise, Thomas H. Fletcher

Faculty Publications

The fundamental combustion behavior of live wildland vegetation is not fully understood. Since the combustion process during wildland fire starts with pyrolysis, there is a need for better understanding of pyrolysis to develop improved wildland fire models. The kinetics of pyrolysis of live and dead wildland vegetation has not been explored in detail. In this study, the pyrolysis kinetics were determined for 14 different plant species (live and dead) which are all native to the forests in the southern United States. Pyrolysis experiments were carried out in a Thermogravimetric analyzer (TGA) under inert conditions at 5 different heating rates ranged …