Engineering Commons^™

Particles In The Great Pinatubo Volcanic Cloud Of June 1991:The Role Of Ice, Song Guo, William I. Rose, Gregg J. S. Bluth, M. I. Watson

Department of Geological and Mining Engineering and Sciences Publications

Pinatubo's 15 June 1991 eruption was Earth's largest of the last 25 years, and it formed a substantial volcanic cloud. We present results of analysis of satellite-based infrared remote sensing using Advanced Very High Resolution Radiometer (AVHRR) and TIROS Operational Vertical Sounder/High Resolution Infrared Radiation Sounder/2 (TOVS/HIRS/2) sensors, during the first few days of atmospheric residence of the Pinatubo volcanic cloud, as it drifted from the Philippines toward Africa. An SO₂-rich upper (25 km) portion drifted westward slightly faster than an ash-rich lower (22 km) part, though uncertainty exists due to difficulty in precisely locating the ash cloud. …

Effect Of Interface Bonding On Spin-Dependent Tunneling From The Oxidized Co Surface, Kirill D. Belashchenko, Evgeny Y. Tsymbal, Mark Van Schilfgaarde, Derek A. Stewart, Ivan I. Oleynik, Sitaram Jaswal

Materials Research Science and Engineering Center: Faculty Publications

We demonstrate that the factorization of the tunneling transmission into the product of two surface transmission functions and a vacuum decay factor allows one to generalize Jullière's formula and explain the meaning of the "tunneling density of states" in some limiting cases. Using this factorization we calculate spin-dependent tunneling from clean and oxidized fcc Co surfaces through vacuum into Al using the principal-layer Green's-function approach. We demonstrate that a monolayer of oxygen on the Co(111) surface creates a spin-filter effect due to the Co-O bonding which produces an additional tunneling barrier in the minority-spin channel. This changes the minority-spin dominated …

Development Of Nanostructure Based Corrosion-Barrier Coatings On Steel For Transmutation Applications, Biswajit Das

Transmutation Sciences Materials (TRP)

The objective of this project is to develop a novel nanostructure based coating technology that will provide significantly improved corrosion resistance for steel in LBE at elevated temperatures (500 - 600^oC), as well as provide long-term reliability under thermal cycling. The nanostructure based coatings will consist of a layer of nanoporous alumina with the pores filled with an oxidizing metal such as Cr, followed by a capping layer of alumina. Alumina, which is a robust anti-corrosion material, provides corrosion resistance at elevated temperatures. The Cr serves two purposes: (1) it acts as a solid filler material for the …

Fundamental Chemistry Of U And Pu In The Tbp-Dodecane-Nitric Acid System, Kenneth Czerwinski, Byron Bennett

Separations Campaign (TRP)

The speciation of hexavalent U and tetravalent Pu will be examined in the TBP-dodecane-nitric acid systems. This topic is chosen based on data needs for separation modeling identified by the AFCI. Emphasis will be placed on studying the influence of nitrate and acetohydroxamic acid on U and Pu speciation as well as conditions where a third phase forms in the organic phase. The organic phase will be 30% TBP in dodecane. Equal volumes of aqueous and organic phase will be used. The speciation of the actinides in the aqueous and organic phase will be determined by a number of different …

Design Concepts And Process Analysis For Transmuter Fuel Manufacturing, Georg F. Mauer

Fuels Campaign (TRP)

This proposal addresses the subject heading ‘Transmutation Fuel Development’ in the 2004 research topic list of the UNLV Transmutation Research Program (TRP) and DOE Advanced Fuel Cycle Initiative (AFCI). The large-scale deployment of remote fabrication and refabrication processes (with a capacity of approx. 100 metric tons of Minor Actinides (MA) annually) will be required for all transmutation scenarios. The objective of this project is the design, analysis, and evaluation of manufacturing processes for transmuter fuel fabrication. Fabrication processes for different fuel types differ in terms of equipment types, throughput, and cost. The evaluation of the fabrication processes will create a …

Growth And Transport Properties Of Complementary Germanium Nanowire Field Effect Transistors, Andrew B. Greytak, Lincoln J. Lauhon, Mark S. Gudiksen, Charles M. Lieber

Faculty Publications

n- and p-type Ge nanowires were synthesized by a multistep process in which axial elongation, via vapor–liquid–solid (VLS) growth, and doping were accomplished in separate chemical vapor deposition steps. Intrinsic, single-crystal, Ge nanowires prepared by Au nanocluster-mediated VLS growth were surface-doped in situ using diborane or phosphine, and then radial growth of an epitaxial Ge shell was used to cap the dopant layer. Field-effect transistors prepared from these Ge nanowires exhibited on currents and transconductances up to 850 µA/µm and 4.9 µA/V, respectively, with device yields of >85%.

Effect Of Silicon Content On The Corrosion Resistance And Radiation-Induced Embrittlement Of Materials For Advanced Heavy Liquid Metal Nuclear Systems, Ajit K. Roy

Transmutation Sciences Materials (TRP)

The purpose of this collaborative research project involving the University of Nevada Las Vegas (UNLV), Los Alamos National Laboratory (LANL) and Idaho State University (ISU) is to evaluate the effect of silicon (Si) content on the corrosion behavior and radiation-induced embrittlement of martensitic stainless steels having chemical compositions similar to that of the modified 9Cr-1Mo 2 steel. Recent studies at LANL involving Alloy EP-823 of different Si content have demonstrated that increased Si content in this alloy may enhance the corrosion resistance in molten lead-bismuth-eutectic (LBE). Since very little data exists in the open literature on the beneficial effect of …

Cross Drain Inspection I-65, Mile-Points 0.00-24.8 And 40.5-91.3, Brad W. Rister, Jonathan Fisher

Kentucky Transportation Center Research Report

The following report contains detailed inspections of cross drains and headwalls located on I-65 in Kentucky from mile point 0.0-24.8 and 40.5-91.3. A condition assessment was performed for each located drainage structure and the discovered distresses were then recorded by location and severity. Of the 830 cross drains inspected, 313 may need some form of remedial action. Of these 313 pipes, 134 may need to be repaired or replaced and 179 may need to be cleaned.

Linear Voltage To Current Conversion Using Submicron Cmos Devices, David J. Comer, Donald Comer, Aaron Shreeve

Faculty Publications

Sponsorship: AMIS--American Micro-Systems, Inc. This paper investigates the linearity of submicron gate length CMOS devices and their behavior in open loop voltage to current (V-I) converters. Methods are developed to estimate the deviation from linearity in V-I converters due to short-channel effects. Using these methods, a converter is designed and fabricated on a 0.35 micron process. The measured deviation from linearity is less than 1% and the simulated bandwidth is 1 GHz.

Investigation Of Nanoporous Thin-Film Alumina Templates, Biswajit Das

Electrical & Computer Engineering Faculty Research

This paper presents the results of a systematic study of the fabrication of thin-film alumina templates on silicon and other substrates. Such templates are of significant interest for the low-cost implementation of semiconductor and metal nanostructure arrays. In addition, thin-film alumina templates on silicon have the potential for nanostructure integration with silicon electronics. Formation of thin-film alumina templates on silicon substrates was investigated under different fabrication conditions, and the dependence of pore morphology and pore formation rate on process parameters was evaluated. In addition, process conditions for improved pore size distribution and periodicity were determined. The template/silicon interface, important for …

Composing Systemic Aspects Into Component-Oriented Doc Middleware, Nanbor Wang

All Computer Science and Engineering Research

The advent and maturation of component-based middleware frameworks have sim-plified the development of large-scale distributed applications by separating system devel-opment and configuration concerns into different aspects that can be specified and com-posed at various stages of the application development lifecycle. Conventional component middleware technologies, such as J2EE [73] and .NET [34], were designed to meet the quality of service (QoS) requirements of enterprise applications, which focus largely on scalability and reliability. Therefore, conventional component middleware specifications and implementations are not well suited for distributed real-time and embedded (DRE) ap-plications with more stringent QoS requirements, such as low latency/jitter, timeliness, and …

Zone Heating For Wean-To-Finish Facilities: A Performance Comparison, Rick R. Stowell

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Farm research trials were conducted in 2003 and 2004 to assess the effects of the type of zone heater and floor mat used in a wean-to-finish building on the thermal environment created for newly weaned pigs and resulting pig performance. Modulated LP gas-fired brooder heaters were compared to electric heat lamps, and floor mats made from farm-cut wood sheathing (3/8” oriented-strand board, OSB) were compared to commercial [unheated] rubber mats in a replicated 2x2 factorial experiment. No consistent differences in air temperature near the heating zone were found between either of the treatments, with treatment means within 1^oF …

Acuta Enews May 2004, Vol. 33, No. 5

ACUTA Newsletters

ln This lssue

Board Approves State of Nominees for 2004-05

From ACUTA Headquarters................................ Jeri A. Semer, CAE, Executive Director

Tech Talk................................... Kevin Tanzillo, Dux Public Relations

Securing Your Wireless Network........................................ Stephen Cobb and Chey Cobb

Board Report............................................. Carmine Piscopo, Providence College, ACUTA Secretary/Treasurer

DC Update..................................... Whitney Johnson, Retired, Northern Michigan Univ.

CUPA-HR Salary Survey

Be a Moderator/Monitor in Chicago............................ Donna Hall, Manager, Professional Development

On-Line Algorithms For Computing Mean And Variance Of Interval Data, And Their Use In Intelligent Systems, Berlin Wu, Hung T. Nguyen, Vladik Kreinovich

Departmental Technical Reports (CS)

No abstract provided.

Application Of Kolmogorov Complexity To Advanced Problems In Mechanics, Vladik Kreinovich, Isaak A. Kunin

Departmental Technical Reports (CS)

In the 1960s, A.N. Kolmogorov described the main reason why a mathematical correct solution to a system of differential equations may be not physically possible: Traditional mathematical analysis tacitly assumes that all numbers, no matter how large or how small, are physically possible. From the engineering viewpoint, however, a number like 10^{10^10} is not possible, because it exceeds the number of particles in the Universe. In this paper, we extend Kolmogorov's ideas from discrete objects to continuous objects known with given accuracy epsilon, and show how this extension can clarify the analysis of dynamical systems.

Using Fft-Based Data Processing Techniques To Characterize Asphaltic Concrete Mixtures, Scott A. Starks, Vladik Kreinovich, Roberto Araiza, Soheil Nazarian, J. Adidhela

Departmental Technical Reports (CS)

A natural way to test the quality of a pavement is to send signals with different frequencies through the pavement and compare the results with the signals passing through an ideal pavement. For this comparison, we must determine how, for the corresponding mixture, the elasticity E depends on the frequency f in the range from 0.1 to 10^5 Hz. It is very expensive to perform measurements in high frequency area (above 20 Hz). To avoid these measurements, we can use the fact that for most of these mixtures, when we change a temperature, the new dependence changes simply by scaling. …

Using 1-D Radar Observations To Detect A Space Explosion Core Among The Explosion Fragments: Sequential And Distributed Algorithms, P. Debroux, J. Boehm, Vladik Kreinovich, Gang Xiang, J. Beck, K. Tupelly, R. Kandathi, Luc Longpre, K. Villaverde

Departmental Technical Reports (CS)

A radar observes the result of a space explosion. Due to radar's low horizontal resolution, we get a 1-D signal s(t) representing different 2-D slices. Based on these slices, we must distinguish between the body at the core of the explosion and the slowly out-moving fragments. We propose new algorithms for processing this 1-D data. Since these algorithms are time-consuming, we also exploit the possibility of parallelizing these algorithms.

Characterization Of Aerobic And Anaerobic Microbial Activity In Hydrocarbon-Contaminated Soil, Lynne C. Maloney, Yarrow M. Nelson, Christopher L. Kitts

Civil and Environmental Engineering

Microbial activity in hydrocarbon-contaminated soil was characterized and quantified to determine the potential for natural attenuation at a former oil field in California. Plate counts, direct microscopic counts, and carbon dioxide and methane production rates were used to quantify the populations and activity of soil microorganisms. Terminal restriction fragment (TRF) analysis provided preliminary identification of dominant microorganisms and community shifts as depth and contaminant concentrations changed. Plate counts under aerobic conditions resulted in 1.5 to 22 × 10⁶ colony-forming units (CFU) per gram of soil, and direct microscopic counts of total bacteria were 3 to 33 × 10^{6 …}

A System For Monitoring Pressures And Spinal Curvature In Spinally Injured People Immobilised On A Spinal Raft, Ruairí De Fréin, Eoin Flinn, Ted Burke

Articles

We present a system designed to study the pressure at various ‘hot spots’ on the back of the body and the deformation of the spine experienced by a patient when strapped to a spinal board, and the potential alleviation of both by the addition of an inflatable “spinal raft” (or other similar device). In measuring pressure we devised a system of air-filled sacks interfaced with a PC. Each sack, placed under a particular key point on the body, is inflated until its faces just begin to separate and a switch thereby opens. The pressure reading is then captured and displayed …

Biological Feasibility And Optimization Of Biosparging At A Hydrocarbon-Contaminated Site, Jason G. Waudby, Yarrow M. Nelson

Civil and Environmental Engineering

The purpose of this study was to identify any biological/chemical factors which may be limiting the biodegradation of total petroleum hydrocarbon (TPH) contaminants at a biosparge site located at a former oil field near Guadalupe, California. Laboratory experiments using a combination of respirometry and TPH analyses were conducted to determine if biodegradation of TPH at the site is limited by a lack of hydrocarbon-degrading microorganisms, depleted inorganic nutrient concentrations, insufficient dissolved oxygen supply, or the chemical composition of the partially biodegraded petroleum constituents in the groundwater. No increase in total CO₂ production was observed in samples with added nutrients, …

Biodegradability And Toxicity Of Hydrocarbon Leachate From Land Treatment Units, Sandy L. Scott, Yarrow M. Nelson

Civil and Environmental Engineering

The biodegradability of leachate from the land treatment of hydrocarbon-contaminated soil was investigated in the laboratory using respirometry and toxicity testing in combination with total petroleum hydrocarbon (TPH) measurements. Soil in land treatment units (LTU) had been contaminated with a diesel-like hydrocarbon mixture formerly used as a diluent for crude oil at an oil field in California. Leachate was collected from two different LTUs for treatability testing in a respirometer under aerobic conditions. Only about 12% reduction in TPH concentration was observed after aeration for 161 days, indicating limited biodegradability of the hydrocarbon constituents in the leachate. Similarly, Microtox® toxicity …

Combining Systematic Layout Planning And Computer Simulation In The Design Of Manufacturing Facilities, Akintoye M. Akinyoade

All-Inclusive List of Electronic Theses and Dissertations

In this study, the systematic layout planning (SLP) and computer simulation were combined to improve the layout design of a manufacturing facility using a case study.

Nu-Deck Precast Deck Panels And Innovative Bridge Research And Construction, Maher K. Tadros, Charles J. Vranek

Nebraska Department of Transportation: Research Reports

Most of the deficiency in existing stringer-type bridges lie in deterioration of the bridge deck. Cast-in-place reinforced concrete decks experience cracking shortly after construction due to large differential creep and shrinkage with the supporting beams, and due to the temperature drop experienced during the hydration cycle. The NUDECK (Nebraska University) system is a full-depth precast/prestressed concrete bridge deck panel system. The combination of high performance precast concrete, where little creep and shrinkage occur after the deck is made composite with the beams, and two-way prestressing assure continued pre-compression of the deck during its life. With this system, construction time and …

Geometry Of Protein Structures. I. Why Hyperbolic Surfaces Are A Good Approximation For Beta-Sheets, Boguslaw Stec, Vladik Kreinovich

Departmental Technical Reports (CS)

Protein structure is invariably connected to protein function. To analyze the structural changes of proteins, we should have a good description of basic geometry of proteins' secondary structure. A beta-sheet is one of important elements of protein secondary structure that is formed by several fragments of the protein that form a surface-like feature. The actual shapes of the beta-sheets can be very complicated, so we would like to approximate them by simpler geometrical shapes from an approximating family. Which family should we choose? Traditionally, hyperbolic (second order) surfaces have been used as a reasonable approximation to the shape of beta-sheets. …

Fuzzy And Probabilistic Models Of Association Information In Sensor Networks, Leon Reznik, Vladik Kreinovich

Departmental Technical Reports (CS)

The paper considers the problem of improving accuracy and reliability of measurement information acquired by sensor networks. It offers the way of integrating sensor measurement results with association information available or a priori derived at aggregation nodes. The models applied for describing both sensor sensor results and association information are reviewed with consideration given to both neuro-fuzzy and probabilistic models and methods. The information sources, typically available in sensor systems, are classified according to the model (fuzzy or probabilistic), which seems more feasible to be applied. The integration problem is formulated as an optimization problem.

Calibration Of Plasma Impedance Probe On The Floating Potential Measurement Unit, Krishna Kishore Kurra

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Charging of the International Space Station (ISS) is identified as a potential space hazard for astronauts. Floating potential measurement unit (FMPU) was developed to address this issue. This project is aimed at developing a procedure for the calibration of Plasma Impedance Probe, one of the four probes housed by FPMU. Non-linear curve fits are used to find the calibration coefficients and the equations are symbolically solved to obtain the load magnitude and phase from the pulse code modulated (PCM) data. There is a brief discussion of various methods tried during this process. The results are compared with the actual test …

Dynamic Mechanical And Thermal Analysis Of Aligned Vapor Grown Carbon Nanofibers Reinforced Polyethylene, Jose Jaime Taha-Tijerina

Theses and Dissertations - UTB/UTPA

Dynamic-mechanical and thermal characterization of aligned vapor grown carbon-nanofibers (VGCNFs)-reinforced high-density polyethylene (HDPE) has been performed. VGCNFs with diameters ranging from 50–200nm were used. Nanofibers were purified to remove amorphous carbon and metal catalyst, resulting in deagglomeration, and creating an open network that allowed polymer infiltration during mixing. High-shear mixing was used to disperse and distribute the nanofibers uniformly within the matrix. Extensional flow at different draw ratios (λ) was used to obtain anisotropic nanoreinforced composite (NC) tapes. Dynamic Mechanical Analysis (DMA) showed a dual increase, in storage and loss modulus, with draw ratio. This behavior is attributed to the …

Hydraulic Characteristics Of Labyrinth Weirs, Corwin M. Willmore

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Primarily, half-round crest labyrinth weirs were tested in this study with the side leg angle (a) ranging between 7 to 35 degrees. Historical data was primarily limited to quarter-round data. This study presents data and equations for estimating the discharge coefficient for labyrinth weirs with both half-round, quarter-round, and two Ogee-type crest weir shapes . A method is presented for comparing the flow capacity between weirs in order to determine the most efficient weir at a given Ht/P. For a labyrinth weir with the crest shape,# of cycles (N), and the cycle width (w) held constant, the discharge coefficient (Cct) …

Cavitation Effects On The Stability Of A Submerged Journal Bearing, Jerzy T. Sawicki, T. V. V. L. N. Rao

Mechanical Engineering Faculty Publications

A computational procedure for the mechanism of shear between the liquid sublayer and air cavity in the cavitation zone of a submerged journal bearing is presented here. Using the mass conservation principle, Elrod's universal equation is modified to take into consideration the shear of the air cavity in the cavitation region. Results of steady state and transient response for the submerged journal bearing using the present approach are compared with the universal equation based on the striated flow in the cavitation region. At steady state, the angular extent of cavitation region predicted by the present approach is higher than that …

Comparison Of Near-Field Millimeter Wave Probes For Detecting Corrosion Pit Under Paint, Mohammad Tayeb Ahmad Ghasr, Sergey Kharkovsky, R. Zoughi, Russell A. Austin

Electrical and Computer Engineering Faculty Research & Creative Works

Corrosion pitting defection is a critical issue in the maintenance of aircraft. Near-field microwave nondestructive techniques have been successfully used for defection of corrosion under paint. In this paper a comparison between several different millimeter wave probes is made for the detection and evaluation of corrosion precursor pitting under paint at Ka-band and V-band. Since the pittings investigated here are very small in size, spatial resolution and sensitivity of the probes are critical issues. If is shown that modified open-ended rectangular probes namely, tapered waveguide and dielectric slab-loaded waveguide probes provide high resolution and sensitivity for the detection and evaluation …