Engineering Commons^™

Preparing Nasa For The 21st Century: Oct Perspective On Edl, Harry Partridge

Ablation Workshop

NASA’s Chief Technologist, within the Office of the Chief Technologist (OCT), is the principal advisor to the NASA Administrator in matters related to Agency-wide technology policy and programs and is responsible for the planning, advocacy and coordination of technology development activities within NASA to meet future mission needs. OCT works with the Mission Directorates and mission planners to infuse new technologies into future missions and with other Governmental Agencies to coordinate technology development efforts of mutual interest. In addition, OCT manages NASA’s Space Technology Program (STP), which also includes the SBIR and STTR programs. In this presentation OCT’s role within …

Introduction: The 5th Ablation Workshop And Beyond, Ioana Cozmuta, Alexandre Martin

Ablation Workshop

No abstract provided.

Ablation Test-Case Series #2. Numerical Simulation Of Ablative-Material Response: Code And Model Comparisons, Jean R. Lachaud, Alexandre Martin, Tom Van Eekelen, Ioana Cozmuta

Mechanical Engineering Faculty Publications

This test-case series on the numerical simulation of the response of ablative-materials really started out of pure curiosity. Code developers and users were curious to see "how the codes compare" and "what is the effect of the different hypotheses in the models implemented". The objective of these test-case series is to propose problems of increasing complexity until it is agreed that the most-elaborated well-defined problem is formulated. The first test-case was mostly a simple heat transfer problem chosen for it’s simplicity (it is summarized in section 2.1). The second test-case series goes one step further, with the objective of reaching …

Ablation Test-Case Series #3. Numerical Simulation Of Ablative-Material Response: Code And Model Comparisons, Tom Van Eekelen, Jean R. Lachaud, Alexandre Martin, Ioana Cozmuta

Mechanical Engineering Faculty Publications

The test-case series #3 will be a further extension of the tests defined within the framework of the NASA ablation modelling workshops. In order to reduce the amount of work, all tests within test-case series #3, will use the TACOT material defined by Lachaud et al. The main goal of this new series, is to test the 3D modelling capabilities of the participating codes. The first 1D results were presented at the 4th Ablation workshop, and together with the results of the second test-case series, will be discussed and analyzed more thoroughly at the 5th Ablation Workshop, Feb. 28- March …

Railroad Subgrade Support And Performance Indicators: A Review Of Available Laboratory And In-Situ Testing Methods, Michael T. Mchenry, Jerry G. Rose

Kentucky Transportation Center Research Report

The quality and support of the subgrade portion of a railroad trackbed are vital to the overall performance of the track structure. The subgrade is an integral component of the track structure and its performance properties must be considered in order to effectively assess its influence on subsequent track quality. European and Asian railways are particularly advanced in implementing subgrade performance indicators into their track designs and assessments. As train speed and tonnage increase in the U.S., the evaluation and influence of subgrade performance will become even more paramount. There are numerous means of measuring and predicting subgrade performance. Both …

High Performance Modeling Of Atmospheric Re-Entry Vehicles, Alexandre Martin, Leonardo C. Scalabrin, Iain D. Boyd

Mechanical Engineering Faculty Publications

Re-entry vehicles designed for space exploration are usually equipped with thermal protection systems made of ablative material. In order to properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled into the boundary layer is complex and may lead to thermal chemical reactions that cannot be captured with simple flow chemistry models. In order to obtain better predictions, an appropriate gas flow chemistry model needs …

Modeling Of Heat Transfer Attenuation By Ablative Gases During The Stardust Re-Entry, Alexandre Martin, Iain D. Boyd

Mechanical Engineering Faculty Publications

The great majority of modern space vehicles designed for planetary exploration use ablative materials to protect the payload against the high heating environment experienced during re-entry. In order to properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled into the boundary layer is complex and may lead to thermal chemical reactions that cannot be captured with simple flow chemistry models. In order to obtain …

Effect Of Applied Magnetic Field On Shock Boundary Layer Interaction, Ovais U. Khan, Alexandre Martin

Mechanical Engineering Faculty Publications

The governing magneto-hydrodynamic (MHD) equations contain classical fluid dynamics equations along with coupled Maxwell’s magnetic induction equations. These equations model both advection and diffusion effects of electromagnetic field. However, available literature indicates that some previous investigations neglect the diffusion of magnetic field and considered only ideal MHD equations for modeling a typical MHD problem. In this work, the effects of magnetic field diffusion term also known as viscous magnetic term have been investigated over flow structure. Low magnetic Reynolds number approximation and ideal full MHD set of equations have been considered and solved using a four-stage modified Runge-Kutta scheme augmented …

A Study Of Queuing Theory In Low To High Rework Environments With Process Availability, Adam J. Brown

Theses and Dissertations--Manufacturing Systems Engineering

In manufacturing systems subject to machine and operator resource constraints the effects of rework can be profound. High levels of rework burden the resources unnecessarily and as the utilization of these resources increases the expected queuing time of work in process increases exponentially. Queuing models can help managers to understand and control the effects of rework, but often this tool is overlooked in part because of concerns over accuracy in complex environments and/or the need for limiting assumptions. One aim of this work is to increase understanding of system variables on the accuracy of simple queuing models. A queuing model …

Fabrication Of Swnts For Water Desalination And Multilayer Structure For Dna Sequencing, Jingyuan Yao

Theses and Dissertations--Chemical and Materials Engineering

0.7nm single wall carbon nanotubes have been synthesized within VPI-5 zeolite channels with sucrose as carbon precursor. VPI-5 molecular sieves are synthesized hydrothermally under conventional heating. X-ray powder diffraction, micro raman, scanning electron microscope (SEM), transmission electron microscope (TEM), Thermogravimetric analysis have been used to investigate the structure of zeolite and thermal decoposition process of carbon precursors. 0.4nm single wall carbon nanotubes have also been fabricated within AlPO₄-5 nanopores. A key challenge is to produce high yield single wall carbon nanotubes with uniform diameter. In order to improve the carbon nanotube yield, different organic precursors are employed. Although …

Economic Modeling & Optimization Of A Region Specific Multi-Feedstock Biorefinery Supply Chain, William H. Faulkner

Theses and Dissertations--Manufacturing Systems Engineering

The objective of this thesis is to include strategic and tactical level decisions into the biorefinery supply chain design for a specific region while comparing multiple conversion technologies and biomass feedstocks. The allocation of biomass feedstocks, products, and the respective supply chain configuration locations are determined while ensuring the regions monthly biomass availability and product market demand constraints are met. This research considers all actions required to bring the bio-based products to market from harvesting, storing, and processing the biomass to market distribution. Two different conversion technologies are chosen for comparison: one advanced conversion technology and one conventional technology. Potential …

Microstructural And Mineralogical Transformation Of Hydraulically Disposed Fly Ash—Implications To The Environment, Jabulani S. Mahlaba, Elsabe P. Kearsley, Richard A. Kruger

Coal Combustion and Gasification Products Journal Archive

Increasing amounts of coal are combusted annually to meet the ever-increasing energy demands. The inevitable by-products include fly ash and saline effluents, which require acceptable disposal. The aim of this article is to compare the effect of hydraulic disposal with dry ash dumping. The results indicate that the former carries more environmental benefits based on the physical, chemical, and mineralogical aspects that were investigated.

Cordyline Fruticosa Growth And Soil Microbial Quality With Topical Application Of Coal Combustion By-Products Aggregates, Sangchul Hwang, Isomar Latorre, Eileen Irizarry

Coal Combustion and Gasification Products Journal Archive

Coal combustion by-products aggregates (CCAs) are a solidified composite of fly and bottom ashes (2:1, by wt). Here, we assessed the feasibility of beneficial use of CCAs as a soil amendment or conditioner by conducting an outdoor experiment with Cordyline fruticosa (lucky plant) to determine its growth and soil microbial quality under the influence of topical CCA application (95 tons ha21). Enhanced growth of C. fruticosa with CCA application was noted, with respect to plant height, growth rate, leaf size, and leaf chlorophyll intensity. Soil dehydrogenase activity and total heterotrophic bacteria count were greater with topical CCA application, especially in …

Influence Of Activator Solution Formulation On Fresh And Hardened Properties Of Low-Calcium Fly Ash Geopolymer Concrete, Carlos Montes, Erez N. Allouche

Coal Combustion and Gasification Products Journal Archive

The effect of the composition of activator solutions on fresh and hardened properties of geopolymer concrete was investigated. Research variables included liquid sodium silicate product (DH, NH, and StarH), sodium hydroxide molar concentration (6, 10, and 14), and sodium silicate–to–sodium hydroxide ratio (1, 2, and 3). Response variables were compressive strength, corrosion resistance expressed as remaining compressive strength and mass loss, and flowability. Results were analyzed using Minitab statistical software. Findings suggest that activator solution formulation has a significant effect on the properties of the resulting geopolymer binder. The experimental design used was found effective in establishing the optimum activator …

Mineralogical Transformations In Coal Feedstocks During Carbon Conversion, Based On Packed-Bed Combustor Tests: Part 2. Behavior Of Individual Particles, Ratale H. Matjie, Colin R. Ward, Zhongsheng Li

Coal Combustion and Gasification Products Journal Archive

Handpicked carbon-rich particles (coal or char), mineral-rich particles (heated stones), and bonded stone aggregates (clinkers) from the upper and lower parts of a pilot-scale packed-bed combustor bed, designed to simulate conversion or combustion processes, were subjected to mineralogical and inorganic geochemical studies, in order to evaluate the reactions that may occur during carbon conversion at a particle-by-particle scale. The mineral matter of the carbon-rich particles was found to have higher proportions of carbonate minerals and kaolinite than the mineral-rich (stone) particles in the coal feedstocks used in the study, and to form phases such as anorthite, gehlenite, pyrrhotite, troilite, and …

Mineralogical Transformations In Coal Feedstocks During Carbon Conversion, Based On Packed-Bed Combustor Tests: Part 1. Bulk Coal And Ash Studies, Ratale H. Matjie, Colin R. Ward, Zhongsheng Li

Coal Combustion and Gasification Products Journal Archive

Mineralogical and inorganic geochemical studies have been carried out on composite samples of six different coarse-crushed (,120 mm) feed coals tested in a pilot-scale packed-bed combustor designed to simulate conversion and some fixed-bed combustion processes, and also on composite samples of the ashes produced. The mineral matter of the coals consisted mainly of quartz, kaolinite, and Ca-bearing carbonate minerals (calcite, dolomite, aragonite), with minor proportions of illite, pyrite, and several other phases, along with some Ca in an organically associated form. The base to acid ratio of the coal ashes ranged from 0.1 to 0.3, due mainly to variations in …

Potential Indoor Air Exposures And Health Risks From Mercury Off-Gassing Of Coal Combustion Products Used In Building Materials, Christopher M. Long, Sonja N. Sax, Ari S. Lewis

Coal Combustion and Gasification Products Journal Archive

Coal combustion products (CCPs), including coal fly ash (CFA) and flue gas desulfurization (FGD) gypsum, have gained accepted use as substitutes for traditional substances in building materials. Because of the presence of mercury (Hg) in CCP materials, some concerns have been raised regarding the potential for Hg to off-gas from building materials into indoor air. Risk assessment offers a well-accepted, objective framework in which to determine whether such off-gassing could result in humanexposures of health concern. We thus conducted a screening-level human health risk assessment to estimate worst-case inhalation risks from indoor air exposures to Hg for multiple CCP utilization …

Quantifying The Benefits Of Using Flue Gas Desulfurization Gypsum In Sustainable Wallboard Production, Jin Cheol Lee, Sabrina L. Bradshaw, Tuncer B. Edil, Craig H. Benson

Coal Combustion and Gasification Products Journal Archive

Electric utilities produce more than 11.2 Mt of flue gas desulfurization (FGD) gypsum annually. Approximately 7.5 Mt is used in wallboard production. This article examines the environmental and cost benefits associated with replacement of natural gypsum in wallboard with FGD gypsum. A life-cycle analysis program was used to quantify the benefits of using FGD gypsum from electric power production in wallboard construction. Comparisons were made between energy consumption, water use, and greenhouse gas (GHG) emissions associated with obtaining and processing virgin gypsum material and those with FGD gypsum. The added impact of disposing of the unused FGD gypsum in landfills …

Waste Classification Of Slag Generated In A Pilot-Scale Entrained-Flow Gasifier, Ashleigh Cousins, Robin W. Hughes, David J. Mccalden, Dennis Y. Lu, Edward J. Anthony

Coal Combustion and Gasification Products Journal Archive

Series of gasification tests have been completed in the pilot-scale entrained-flow slagging gasifier at CanmetENERGY using Canadian coals, oil-sand coke, and blends of these fuels to determine if the produced slags are nonhazardous in nature. Solid wastes generated during these tests were analyzed for their trace metals, crystallinity, and toxic constituent leaching tendency in an attempt to provide more insight into the possibility of disposal or by-product use of gasifier-produced solid waste. The gasification tests were performed at conditions representative of commercial gasifiers using a dry-fuel-feed configuration. The lower-volatility elements were found to partition between the slag and process-water solids …

Kentucky Water Resources Research Institute Annual Technical Report Fy 2011, Kentucky Water Resources Research Institute, University Of Kentucky

KWRRI Annual Technical Reports (USGS’s 104b Grant Program)

The FY2011 Annual Technical Report for Kentucky consolidates reporting requirements for the Section 104(b) base grant award into a single document that includes; 1) a synopsis of each research project that was conducted during the period, 2) citations for related publications, reports, and presentations, 3) a description of information transfer activities, 4) a summary of student support during the reporting period, and 5) notable awards and achievements during the year.

Project 2011KY166B (Sewage to fertilizer: a proposed solution to water pollution) was not initiated because the principal investigator (Dr. Rebecca Evans Kelley) resigned from the Department of Biological Sciences at …

The Influence Of Membrane Cholesterol-Related Shear Stress Mechanosensitivity On Neutrophil Flow Behavior, Xiaoyan Zhang

Theses and Dissertations--Biomedical Engineering

Hypercholesterolemia is a dominant risk factor for a variety of cardiovascular diseases and involves a chronic inflammatory component in which neutrophil activity plays a critical role. Recently, fluid shear stress mechanotransduction has been established as a control mechanism that regulates the activity of neutrophils by reducing the formation of pseudopods and the surface expression of CD18 integrins, thereby rendering these cells rounded, deformable, and non-adhesive. This is critical for maintaining a healthy circulation, because chronically activated neutrophils not only release excess cytotoxic and degradative agents but also exhibit a reduced efficiency to pass through the small vessels of the microcirculation …

Development Of Performance Measures And Revenue Projections For State Highway Transportation Systems, Dwight V. Denison, Christopher Jepsen, Bryan Gibson, Candice Wallace, Doug Kreis

Kentucky Transportation Center Research Report

The purpose of this report is to develop a pilot model that demonstrates how metrics can be identified and reported in a “dashboard” format to be used to monitor the progress of a transportation system in efficiently meeting established priorities. An additional component of this research is to examine the revenue implications of a shift away from the traditional funding mechanism on the financial viability of state transportation systems.

Kentucky Traffic Collision Facts 2012 Report, Kentucky Transportation Center, Kentucky State Police

Kentucky Transportation Center Research Report

KENTUCKY’S TRAFFIC COLLISION FACTS report for 2012 is based on collision reports submitted to the Kentucky State Police Records Branch. As required by Kentucky Revised Statutes 189.635, “every law enforcement agency whose officers investigate a vehicle accident of which a report must be made...shall file a report of the accident...within ten days after investigation of the accident upon forms supplied by the bureau.” The stated purpose of this requirement is to utilize data on traffic collisions for such purposes as will improve the traffic safety program in the Commonwealth. Data contained in this report are based solely on the observations …

Improvement Of Silicon Oxide Quality Using Heat Treatment, Lei Han

Theses and Dissertations--Electrical and Computer Engineering

In decades, the tremendous development of integrated circuits industry could be mostly attributed to SiO2, since its satisfactory properties as a gate dielectric candidate. The effectivity of SiO2 has been challenged since dielectric layer was scaled down below 3nm, when the gate leakage current of SiO2 became unacceptable. Institution to silicon-based CMOS techniques were proposed, but they have their own limitations. Nowadays, materials with high dielectric constants are mainstream gate dielectric materials in industry, but a SiO2 interfacial layer is still necessary to avoid gap between gate dielectric layer and Si substrate, and to minimize interface trap charges. In this …

Collectors For Enabling Flotation Of Oxidized Coal, Raghav M. Dube

Theses and Dissertations--Mining Engineering

The coalburg seam coal is an example of difficult to float bituminous coal. Laboratory tests conducted on coalburg flotation feed sample revealed recovery values around 28% with 15% product ash when using fuel oil as collector under natural pH conditions. A detailed study showed that increasing pH from natural value of 5.6 to 7.5 provided a significant improvement in recovery of approximately 32 absolute percentage points. The improvement is believed to be result of the release of humic acids from the surface and the dispersion of clay particles thereby leaving a more hydrophobic surface.

Based on the tests conducted with …

Validation Of Computational Fluid Dynamic Simulations Of Membrane Artificial Lungs With X-Ray Imaging, Cameron Christopher Jones

Theses and Dissertations--Biomedical Engineering

The functional performance of membrane oxygenators is directly related to the perfusion dynamics of blood flow through the fiber bundle. Non-uniform flow and design characteristics can limit gas exchange efficiency and influence susceptibility of thrombus development in the fiber membrane. Computational fluid dynamics (CFD) is a powerful tool for predicting properties of the flow field based on prescribed geometrical domains and boundary conditions. Validation of numerical results in membrane oxygenators has been predominantly based on experimental pressure measurements with little emphasis placed on confirmation of the velocity fields due to opacity of the fiber membrane and limitations of optical velocimetric …

Use Of Hybrid Diffuse Optical Spectroscopies In Continuous Monitoring Of Blood Flow, Blood Oxygenation, And Oxygen Consumption Rate In Exercising Skeletal Muscle, Katelyn Gurley

Theses and Dissertations--Biomedical Engineering

This study combines noninvasive hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] with occlusive calibration for continuous measurement of absolute blood flow (BF), tissue blood oxygenation (S_tO₂), and oxygen consumption rate (VO₂) in exercising skeletal muscle. Subjects performed rhythmic dynamic handgrip exercise, while an optical probe connected to a hybrid NIRS/DCS flow-oximeter directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO₂], [Hb], and [tHb]), S_tO₂, relative BF (rBF), and relative VO₂ (rVO₂) in the forearm flexor muscles. Absolute baseline BF and …

Shear Strength Of Web-Tapered I-Shaped Members, Ryan Paul Studer

Theses and Dissertations--Civil Engineering

Plate girders are fabricated in situations where standard structural shapes do not possess the required strength necessary to carry applied loads. In many instances, plate girders are tapered so that the resistance to bending is proportional to the bending moment, creating cost effective, aesthetically pleasing structures. The AISC 2010 Specifications accurately predict the flexural capacity of tapered plate girders but recent research has suggested that the required shear strength is overly conservative. The researchers postulate that the required shear strength is overly conservative due to an effect known as modified shear that has been neglected from the AISC 2010 Specifications …

Bisphosphonates And Bone Microdamage, William A. Caruthers

Theses and Dissertations--Biomedical Engineering

Osteoporosis is a significant healthcare issue due to the increasing elderly population. Bisphosphonates are used to treat osteoporosis by reducing the rate of resorption, increasing bone mineral density (BMD) and thereby reducing fracture risk. Long-term bisphosphonate treatment, however, has been associated with low-energy fractures. Bone microdamage may provide a partial explanation for one of the mechanisms responsible for these fractures since it has been shown to reduce bone toughness, fracture resistance, and bone strength. The goal of this study was to quantify the changes in bone microdamage parameters with the duration of bisphosphonate treatment. This study selected, stained, and histomorphometrically …

Identifying Hot-Spots Of Fecal Contamination In The Royal Spring Karstshed, Samuel C. Lee

Theses and Dissertations--Civil Engineering

The City of Georgetown, Kentucky relies on a vast karst spring network as a drinking water source. This karst feature has several inputs from sinkholes and streams in the Cane Run Watershed: a watershed associated with a variety of land uses in the recharge area. The recharge area encompasses the area from North Lexington to Georgetown and is composed of urban, suburban, agricultural and industrial usage. A serious water quality issue exists with respect to the impact of fecal contamination within the spring recharge area. Identification of fecal contamination is quantified by microbial indicators adapted from surface water applications: fecal …