Engineering Commons^™

Compilation And Generation Of Multi-Processor On A Chip Real-Time Embedded Systems, Randall S. Klingler

Theses and Dissertations

Current FPGA technology has advanced to the point that useful embedded System-on-Programmable-Chips (SoPC)s can now be designed. The Real Time Processor (RTP) project leverages the advances in FPGA technology with a system architecture that is customizable to specific real-time applications. The design and implementation of the framework for architecting such a system from ANSI-C code is presented. The Small Device C Compiler (SDCC) was retargeted to the RTP architecture and extended to produce a generator directive file. The RTPGen hardware generator was created to consume the directive file and produce a highly customized top-level structural VHDL file that can be …

Space Suit Concepts And Vehicle Interfaces For The Constellation Program, D. M. Klaus, J. Metts, R. Kobrick, M. Mesloh, T. Monk, Et Al.

Publications

In carrying out NASA’s Vision for Space Exploration, a number of different environments will be encountered that will require the crew to wear a protective space suit. Specifically, four suited mission phases are identified as Launch, Entry & Abort profiles, Contingency 0g (orbital) Extravehicular Activity (EVA), Lunar Surface EVA and Martian Surface EVA. This study presents conceptual design solutions based on a previous architecture assessment that defined space suit operational requirements for four proposed space suit configuration options. In addition, a subset of vehicle interface requirements are defined for enabling umbilical and physical connections between the suits and the various …

Bubble Dynamics Of Ultrasonic Drug Release From Polymeric Micelles, Mario A. Diaz, William G. Pitt

Faculty Publications

We have reported the ability of Pluronic P-105 micelles to sequester anthracycline drugs and release their contents upon application of 70 kHz ultrasound (US)1 (Figure 1). Optimal targeting to tumors depends on focus and control of US insonation, which is better achieved at higher frequencies. While no evidence of in vitro drug release was found at 500 kHz, drug release at 70 kHz correlates with the intensity of the subharmonic signal in the acoustic spectrum generated by the insonated bubbles2(Figure 2). Having established that bubble oscillations (cavitation) are directly related to drug release at 70 kHz, we now investigate the …

Ultrasonically-Assisted Drug Delivery In Rats Reduces Tumor Growth, William G. Pitt, Beverly L. Roeder, G. Bruce Schaalje, Bryant J. Staples

Faculty Publications

Previously we have shown that nanosized drug carriers called Plurogels™ sequestered Doxorubicin (Dox) and partially released this drug with application of ultrasound (US) (Fig. 1)1. The application to chemotherapy was successfully demonstrated in a rat tumor model2. However previous studies did not examine the distribution of Dox in the insonated and control tissue. This recent work investigated the effect of two US frequencies and examined the Dox distribution in the insonated and control tumors to determine if US was depositing more Dox at the insonated site.

Development Of Deployable Wings For Small Unmanned Aerial Vehicles Using Compliant Mechanisms, Steven D. Landon

Theses and Dissertations

Unmanned Air Vehicles (UAVs) have recently gained attention due to their increased ability to perform sophisticated missions with less cost and/or risk than their manned counterparts. This thesis develops approaches to the use of compliant mechanisms in the design of deployable wings for small UAVs. Although deployable wings with rigid-link mechanisms have been used in the past to maintain flight endurance while minimizing required storage volume, compliant mechanisms offer many advantages in manufacturability and potential space savings due to function sharing of components. A number of compliant, deployable wing concepts are generated and a classification system for them is formed. …

Wide-Angle, High-Extinction-Ratio, Infrared Polarizing Beam Splitters Using Frustrated Total Internal Reflection By An Embedded Centrosymmetric Multilayer, Siva R. Perla, R. M.A. Azzam

Electrical Engineering Faculty Publications

A centrosymmetric multilayer stack of two transparent thin-film materials, which is embedded in a high-index prism, is designed to function as an efficient polarizer or polarizing beam splitter (PBS) under conditions of frustrated total internal reflection over an extended range of incidence angles. The S(LH)^kLHL(HL)^kS multilayer structure consists of a high-index center layer H sandwiched between two identical low-index films L and high-index-low-index bilayers repeated (k times) on both sides of the central trilayer maintaining the symmetry of the entire stack. For a given set of refractive indices, all possible solutions for the thicknesses of …

Understanding Sub-20 Nm Breakdown Behavior Of Liquid Dielectrics, Kumar R. Virwani, Ajay P. Malshe, Kamlakar P. Rajurkar

Department of Industrial and Management Systems Engineering: Faculty Publications

Nanoscale confinement of dielectric molecules is expected to influence their breakdown mechanism in applications such as nanoprobe based machining, molecular electronics, and other related technologies. This Letter presents the first experimental study of the breakdown of nonpolar, nonthiolated liquid dielectrics in the nanometer regime and develops a field emission assisted avalanche based approach to model such behavior. The studies show that dielectric breakdown in the sub-20 nm regime is independent of the cathode materials and is dominated by the electron emission and atomic cluster migration due to the ‘‘sub-20 nm scale confinement of the liquid dielectric.’’

Friction Stir Welding Of High-Strength Automotive Steel, Eric Michael Olsen

Theses and Dissertations

The following thesis is a study on the ability to create acceptable welds in thin-plate, ultra-high-strength steels (UHSS) by way of friction stir welding (FSW). Steels are welded together to create tailor-welded blanks (TWB) for use in the automotive industry. Dual Phase (DP) 590, 780, and 980 steel as well as Transformation-Induced Plasticity (TRIP) 590 steel with thicknesses ranging from 1.2 mm to 1.8 mm were welded using friction stir welding under a variety of processing conditions, including experiments with dissimilar thicknesses. Samples were tested under tensile loads for initial determination if an acceptable weld had been created. Acceptable welds …

Detection Of Ultrathin Biological Films Using Vacuum Ultraviolet Spectroscopic Ellipsometry, Dileep K. Goyal, Greg K. Pribil, John A. Woollam, Anuradha Subramanian

Anuradha Subramanian Publications

Spectroscopic ellipsometry (SE) is a non-contact and a non-destructive optical technique used in characterization of thin films. It is widely used to determine optical constants, thickness in multilayer stacks and microstructure (voids, alloy fraction, or mixed phase composition). This paper reports on a systematic investigation of the optical properties of two different kinds of silane compounds: 3-aminopropyltriethoxysilane (APTES) and 3-glycidoxypropyltriethoxy-silane (GPS) as well as for immunoglobulin G (IgG) attached to these modified samples using vacuum ultraviolet spectroscopic ellipsometry (VUV-SE). VUV-SE is a newly developed technique and used to evaluate the strength and energy of the interband electronic excitations/transitions in these …

Physisorption Of Nucleobases On Graphene: Density-Functional Calculations, Gowtham S, Ralph H. Scheicher, Rajeev Ahuja, Ravindra Pandey, Shashi P. Karna

Data Science Publications

We report the results of our first-principles investigation on the interaction of the nucleobases adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U) with graphene, carried out within the density-functional theory framework, with additional calculations utilizing Hartree-Fock plus second-order Møller-Plesset perturbation theory. The calculated binding energy of the nucleobases shows the following hierarchy: G>A≈T≈C>U, with the equilibrium configuration being rather similar for all five of them. Our results clearly demonstrate that the nucleobases exhibit significantly different interaction strengths when physisorbed on graphene. The stabilizing factor in the interaction between the base molecule and graphene sheet is …

North American Specification For The Design Of Cold-Formed Steel Structural Members, 2007 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Room Temperature Operational Single Electron Transistor Fabricated By Focused Ion Beam Deposition, P. Santosh Kumar Karre, Paul Bergstrom

Department of Electrical and Computer Engineering Publications

We present the fabrication and room temperature operation of single electron transistors using 8nm8nmtungsten islands deposited by focused ion beamdeposition technique. The tunnel junctions are fabricated using oxidation of tungsten in peracetic acid. Clear Coulomb oscillations, showing charging and discharging of the nanoislands, are seen at room temperature. The device consists of an array of tunnel junctions; the tunnel resistance of individual tunnel junction of the device is calculated to be as high as 25.13GΩ25.13GΩ. The effective capacitance of the array of tunnel junctions was found to be 0.499aF0.499aF, giving a charging energy of 160.6meV160.6meV.

Extended Abstract Rotopod: A Novel Approach To Efficient Legged Locomotion, Damian M. Lyons

Faculty Publications

A number of attempts have been made to integrate the efficiency of wheeled locomotion with the terrain versatility of legged locomotion, e.g., Univ.Michigan’s Rhex platform and Case Western’s Whegs. Those platforms cast legs as rotating spokes placed traditionally at the corners of a rectangular platform. In this paper, we present an alternate approach, with three legs radiating down from a central hub. The energy to move the platform is generated by a rotating reaction mass mounted at the hub and, at rest, rotating parallel to the ground plane.

Our approach is to construct a platform whose natural, uncontrolled motion is …

Preface, Hans Müller-Steinhagen, M. Reza Malayeri, A. Paul Watkinson

Heat Exchanger Fouling and Cleaning VII

No abstract provided.

Table Of Contents, Hans Müller-Steinhagen, M. Reza Malayeri, Paul Watkinson

Heat Exchanger Fouling and Cleaning VII

No abstract provided.

Applying Technology Advancements To Improve Heat Exchanger Economic And Environmental Performance In Refinery Crude Preheat Trains, Himanshu Joshi, Fred Hoeve, Eric Van Der Zijden

Heat Exchanger Fouling and Cleaning VII

Fouling of heat exchangers in crude preheat trains is a major refinery operations business factor. It is realised that fouling cannot be completely eliminated, but considerable economic and environmental benefits are available with the proper application of improved technology in both the equipment and software asset management tools areas. This paper presents a technology update of refinery applications of a heat exchanger network analysis software to identify optimal crude preheat train cleaning.

Designing Two-Phase Flow Heat Exchangers For Mitigating Fouling, C.B. Panchal, Blazo Ljubicic

Heat Exchanger Fouling and Cleaning VII

Significant progress has been made in understanding the underlying mechanisms of hydrocarbon fouling and characterizing the effects of physical and chemical parameters in single-phase flows. However, the interactive effects of two-phase flows and fouling mechanisms are poorly understood. Many of the industrial heat exchangers in refining and petrochemical processing operate under multiphase flow conditions with varying flow regimes. Fouling and localized corrosion are generally experienced due to maldistribution of vapor and liquid phases in such heat exchangers. This is because design methods are inadequate to determine localized process conditions that could induce severe fouling locally, which could also lead to …

Crystallization Fouling Behaviour Of Uranium Oxide And Alumnosilicate Scale In High Level Nuclear Waste Medium, Jonas Addai-Mensah, Jun Li, Bill Wilmarth

Heat Exchanger Fouling and Cleaning VII

During high level nuclear waste (HLNW) liquor processing in evaporators operating in the temperature range 30 - 140 °C, dissolved silica, alumina, sodium hydroxide, uranium-235 and transuranic species (e.g. plutonium-238) invariably become concentrated. As the liquor evaporation proceeds, the sodium aluminosilicate (SAS) and radionuclides may exceed their solubility limits and co-precipitate, fouling the tubes and walls of the evaporator. If the fouling process is not effectively controlled or mitigated, radionuclide scale accumulation exceeding the critical mass necessary for self-sustaining nuclear fission reaction may proceed at an alarming rate, posing a serious criticality concern. To probe the mechanisms underpinning uranium oxide-sodium …

Precipitation And Fouling In Heavy Oil–Diluent Blends, E Hong, A. Paul Watkinson

Heat Exchanger Fouling and Cleaning VII

Heavy oil fractions rich in asphaltenes were mixed with diluents containing from 0.6-25% aromatics, and the resulting blends subjected to batch precipitation experiments at 85°C, and thermal fouling tests at surface temperatures in the range 230-310ºC. Deposit compositions were determined, and are compared with suspended asphaltene composition. When the heavy oils were blended with the most aromatic diluents, precipitation and fouling were negligible. As the aromaticity of the diluents was decreased, the extent of asphaltene precipitation and the fouling rates increased. The solubility parameter of the blends, δmix, and the flocculation solubility parameter for asphaltenes, δf , were determined from …

Costs Due To Utility Fouling In China, Xu Zhi-Ming, Zhang Zhong-Bin, Yang Shan-Rang

Heat Exchanger Fouling and Cleaning VII

This paper puts forward a method for evaluating the fouling costs of boilers and turbines in power plants. Furthermore, the Huaneng Dalian Power Plant and Changshan Power Plant are taken as examples for analyzing the costs of fouling. Based on data of on-site measurements in the above Power Plants, the costs due to fouling such as excess surface area, product loss, operating maintenance and increase of product costs are calculated. Results show that the total economical loss due to boiler and turbine fouling in China reaches 4.68 billion dollars, which covers is about 0.169% GDP of China in 2006.

Crude Oil Fouling In A Pilot-Scale Parallel Tube Apparatus, B. D. Crittenden, S. T. Kolaczkowski, T. Takemoto, D. Z. Phillips

Heat Exchanger Fouling and Cleaning VII

Maya crude oil fouling reveals a seemingly straightforward dependency of initial fouling rate on surface temperature but a maximum is found in the initial fouling rate – velocity relationship which mirrors that found in a model chemical system of styrene polymerization. The linear dependency of the logarithm of the pre-exponential factor on apparent activation energy for the crude oil is also found in the styrene system. The apparent activation energy for the crude oil ranged from 26.4 kJ/mol at 1.0 m/s to 245 kJ/mol at 4.0 m/s. Such strong dependencies of apparent activation energy on velocity, even at high velocity, …

Crude Oil Fouling: Petronas Refineries Experience, M.S. Rafeen, M.F. Mohamed, M.Z. Mamot, N.A. Manan, Dr A. Shafawi, Dr M. Ramasamy

Heat Exchanger Fouling and Cleaning VII

Managing crude oil fouling has been a challenge in PETRONAS refineries. Over the past several years, numerous initiatives have been conducted in order to have better control of the situation [1][2][3][4]. The control strategy currently implemented is to periodically clean the heat exchanger based on the heat exchanger monitoring parameter and supported by antifouling chemical injection program. A review was conducted in one of PETRONAS’ refineries in order to come up with a better fouling control strategy. The review is separated into two parts. Firstly, the plant operational data for two selected hot pre-heat exchanger trains was analyzed. From the …

Scale Deposits In Porous Media And Their Removal By Edta Injection, J. Moghadasi, H. Müller-Steinhagen, M. Jamialahmadi, A. Sharif

Heat Exchanger Fouling and Cleaning VII

Formation damage has been observed in several oil reservoirs and production equipment in Iranian oil fields. Laboratory and field testing confirmed that the primary cause of damage was the build-up of calcium carbonate, calcium sulfate and strontium sulfate scale either in the perforation tunnels or in the formation sandstone nears the wellbore. Conventional acid treatments could dissolve this scale, but scale precipitation from the spent acid caused rapid productivity decline. A scale removal treatment with Na2H2EDTA has been developed that can effectively dissolve scale and chelate the dissolved metal ions. Chelation of the dissolved scale prevents scale reprecipitation. This study …

The Effect Of Fouling On Heat Transfer, Pressure Drop And Throughput In Refinery Preheat Trains: Optimisation Of Cleaning Schedules, E. M. Ishiyama, W. R. Paterson, D. I. Wilson

Heat Exchanger Fouling and Cleaning VII

Optimising cleaning schedules for refinery preheat trains requires a robust and reliable simulator, reliable fouling models and the ability to handle the thermal and hydraulic impacts of fouling. The interaction between thermal and hydraulic effects is explored using engineering analyses and fouling rate laws based on the ‘threshold fouling’ concept; the potential occurrence of a new phenomenon, ‘thermo-hydraulic channeling’ in parallel heat exchangers, is identified. The importance of the foulant thermal conductivity is highlighted. We also report the development of a highly flexible preheat train simulator constructed in MATLAB&#;/Excel&#;. It is able to accommodate variable throughput, control valve operation and …

Formation Of Gum And Deposits In An Oxygenated Naphtha Stream, Yonghua Li, Paul Watkinson, Patricio Herrera, Feridoun Fahiminia, Morgan James

Heat Exchanger Fouling and Cleaning VII

Gums formed when organic fluids are in contact with air can cause fouling of process equipment. The oxidation and formation of gum in a naphtha stream was studied in a stirred batch reactor as a function of temperature (96 to 130ºC) and at a total pressure of 584 kPa. Mixtures of air and nitrogen in the pressurizing gas gave dissolved oxygen contents in the range 10-270 ppm wt. Peroxide and existent (dissolved) gum contents were measured over periods of up to 80 hours. Rates of reaction were low, with maximum concentrations of peroxide typically below 4 meq/L, and gum formation …

Observation Of An Isokinetic Temperature And Compensation Effect For High Temperature Crude Oil Fouling, C. A. Bennett, R. S. Kistler, K. Nangia, W. Al-Ghawas, N. Al-Hajji, A. Al-Jemaz

Heat Exchanger Fouling and Cleaning VII

The initial fouling rates of four crude oils were determined at a nominal bulk temperature of 315 °C, an initial heated wall shear stress of 13 Pa, and initial surface temperatures between 375 and 445 °C. These initial fouling rates ranged from 1.3(10-6) to 7.8(10-5) m2 K/kJ. Corresponding Arrhenius plots were linear with the initial fouling rates passing through an isokinetic temperature of 407.5 °C. A plot of the natural logarithm of the preexponential factors (7.6(104) – 5.2(1015) m2 K/kJ) versus the apparent activation energies (128 – 269 kJ/mol) was also linear, confirming the validity of the isokinetic temperature and …

Investigation Of The Mechanisms Of Heat Exchanger Corrosion In A Municipal Waste Incineration Plant By Analysis Of The Raw Gas And Variation Of Operating Parameters, C. Deuerling, J. Maguhn, H. Nordsieck, B. Benker, R. Zimmermann, R. Warnecke

Heat Exchanger Fouling and Cleaning VII

The detailed mechanism of high temperature chlorine corrosion, the dominant cause of corrosion in a municipal solid waste incinerator (MSI), has still to be clarified (Schroer, 2002). Upon its way through the boiler the raw gas is subject to various physical and chemical processes and interactions. Of these, sulphation of chlorides is supposed to have the major impact on chlorine corrosion (Neumann, 1997). The physical and chemical mechanisms of corrosion were investigated at a municipal solid waste incinerator. Both, the particulate and gas phase of the flue gas, were chemically and physically analyzed during their way through the boiler, at …

Milk Protein Fouling In A Tubular Heat Exchanger: Effect Of Milk Temperature And Reynolds Number, D.H.G. Pelegrine, K.F. Oliveira, M.T.M.S. Gomes

Heat Exchanger Fouling and Cleaning VII

In the present work, β-lactoglobulin fouling phenomenon was studied, when milk flowed in a tubular heat exchanger, where hot water was used to raise milk temperature. Experiments have been carried out to determine the effect of Reynolds number and fluid temperature in whey protein fouling, in a tubular heat exchanger and the results showed that fouling increases as the fluid temperature increases. In addition, as the Reynolds number increases, the total amount of fouling (obtained by integrating the whole amount of deposit down the tube dividing by the total area) decreased.

The Thermo-Hydrodynamics Of A Concentric Ohmic Heater For Processing Dairy Fluids, H.J. Tham, X.D. Chen, B. Young, B. Bansal, L. Zhang, G. Duffy

Heat Exchanger Fouling and Cleaning VII

The thermo-hydraulic performance of a 300W concentric annular ohmic heater was investigated. To minimize possible electrochemical reactions and corrosion, a higher frequency was applied and factors of field strength and frequency were studied. 2D computer simulation solving momentum, thermal and electrical energy was performed using the FlexPDE software. A good agreement between experimental and analytical analysis of static heating was obtained. There were significant differences between calculated and measured wall temperature near the entrance. The calculated outlet temperature was however in reasonable agreement with the experiment value.

Influence Of Different Surface Materials On Nucleation And Crystal Growth In Heat Exchangers, T. Geddert, S. Kipp, W. Augustin, S. Scholl

Heat Exchanger Fouling and Cleaning VII

The influence of different materials on the fouling tendency in saline calcium sulfate solution was investigated. The effects of the untreated material on the crystallization process have been studied experimentally in the micro- and macroscopic scale. The crystallization in the induction period was visualized with SEM and AFM to locate preferred nucleation spots and to visualize the crystal growth. The different materials are showing different crystal growth behavior (number and size of the crystals). These results are corresponding with the macroscopic fouling results with limited shear stress. Also different roughness values on stainless steel have been studied with respect to …