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Full-Text Articles in Engineering
An Acoustic-Based Approach For Condition Monitoring Of Pipes, Muhammad S. Khan, Turaj Ashuri, Mitchell Collins, Geoffrey Birkemeier, Emad Almohmmedali
An Acoustic-Based Approach For Condition Monitoring Of Pipes, Muhammad S. Khan, Turaj Ashuri, Mitchell Collins, Geoffrey Birkemeier, Emad Almohmmedali
Journal of the Arkansas Academy of Science
Polyvinyl chloride pipes are extensively used in municipal sewer systems. As the sewer system ages, polyvinyl chloride pipes become prone to developing cracks that can release toxic effluents into the environment. Traditionally, utility operators pass a close circuit television camera mounted on a guided vehicle through the pipe to monitor the defects. The video is observed by a trained operator who records the condition of the pipe. This arrangement has two major limitations. First, it is expensive due to complex set up. Second, if a pipe is blocked the guided vehicle cannot pass through its entire length. A more economical …
Polyethylene Oxide Nanofiber Production By Electrospinning, H. E. Schneider, J. G. Steuber, W. Du, M. Mortazavi, D. W. Bullock
Polyethylene Oxide Nanofiber Production By Electrospinning, H. E. Schneider, J. G. Steuber, W. Du, M. Mortazavi, D. W. Bullock
Journal of the Arkansas Academy of Science
Electrospinning is an inexpensive technique that is used to produce nanofibers for a variety of applications. In electrospinning, a polymer solution is dispensed from a hypodermic-like syringe where an intense electric field attracts the solution to a collector while drawing the polymer into a very thin fiber. The diameter of the fiber can be controlled by tuning the process parameters such as the applied electric field, solution flow rate, distance between syringe tip and collector, and the collector geometry. In this paper we describe results from electrospinning poly(ethylene oxide) (PEO), a likely candidate for applications involving scaffolding for tissue engineering. …
Synchronization Limits Of Chaotic Circuits, C. M. Church, Stephen R. Addison
Synchronization Limits Of Chaotic Circuits, C. M. Church, Stephen R. Addison
Journal of the Arkansas Academy of Science
Through system modeling with electronic circuits, two circuits were constructed that exhibit chaos over a wide ranges of initial conditions. The two circuits were one that modeled an algebraically simple “jerk” function and a resistor-inductor-diode (RLD) circuit where the diode was reverse-biased on the positive voltage cycle of the alternating current source. Using simulation data from other experiments, the waveforms, bifurcation plots, and phase space plots of the concrete circuit were verified. Identical circuits were then built containing variable components and coupled to their original, matching circuits. The variable components were used to observe a wide range of conditions to …
Measuring Pain Withdrawal Threshold Using A Novel Device In "Pseudo-Continuous" Mode, A. H. Walker, S. Thurman, N. Martinez, S. Burns, M. Dobretsov
Measuring Pain Withdrawal Threshold Using A Novel Device In "Pseudo-Continuous" Mode, A. H. Walker, S. Thurman, N. Martinez, S. Burns, M. Dobretsov
Journal of the Arkansas Academy of Science
The study of pain and analgesia is an important area of biomedical research that has led to a significant number of advances in the treatment of acute and chronic pain. This study introduces a novel approach to mechanical testing of pain withdrawal of a rat hind paw to a stimulus. This systematic method involves a modified electronic esthesiometer controlled by an IDEA drive that allows for consistency in experiments. The device gives the experimenter computer control of the step size and velocity of approach of the probe stimulus. We discuss here some of the limitations in the current techniques used …
Improvement Of Prony's Method Of System Identification Via Nonlinear Parameter Transformation, C. Wu
Improvement Of Prony's Method Of System Identification Via Nonlinear Parameter Transformation, C. Wu
Journal of the Arkansas Academy of Science
This paper presents an approach to improve Prony’s method of identifying a linear time-invariant system. The method is based on a nonlinear transformation of parameters, which leads to data averaging. The method yields better results than a direct application of the least squares approach to Prony’s method. A numerical example is given to demonstrate the improvement attained by the new algorithm. Signals are assumed to be contaminated by zero-mean Gaussian white noise.
Novel High Frequency Silicon Carbide Static Induction Transistor-Based Test-Bed For The Acquisition Of Sic Power Device Reverse Recovery Characteristics, Kevin M. Speer, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth, Kraig J. Olejniczak
Novel High Frequency Silicon Carbide Static Induction Transistor-Based Test-Bed For The Acquisition Of Sic Power Device Reverse Recovery Characteristics, Kevin M. Speer, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth, Kraig J. Olejniczak
Journal of the Arkansas Academy of Science
A test system is presented that utilizes a high-frequency Silicon Carbide (SiC) Static Induction Transistor (SIT) in place of the traditional MOSFET to test reverse recovery characteristics for the new class of SiC power diodes. An easily implementable drive circuit is presented that can drive the high-frequency SIT. The SiC SIT is also compared to a commonly used Si MOSFET in the test circuit application.
Parameter Extraction Software For Compact Diode Model, Maruf Hossain, Edgar Cilio, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth
Parameter Extraction Software For Compact Diode Model, Maruf Hossain, Edgar Cilio, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth
Journal of the Arkansas Academy of Science
No abstract provided.
Testing And Modeling Electrical Characteristics Of Novel Silicon Carbide (Sic) Static Induction Transistors (Sits), Avinash S. Kashyap, Sharmila D. Mangan Lal, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth
Testing And Modeling Electrical Characteristics Of Novel Silicon Carbide (Sic) Static Induction Transistors (Sits), Avinash S. Kashyap, Sharmila D. Mangan Lal, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth
Journal of the Arkansas Academy of Science
No abstract provided.
Co-Polymers Of Furan With Pyrrole Or Thiophene: A Synthetic Study, Rose M. Mcconnell, Walter E. Godwin, Susan E. Baker, Kenya Powell, Martha Baskett, Amy Morara, Xiadong Ma
Co-Polymers Of Furan With Pyrrole Or Thiophene: A Synthetic Study, Rose M. Mcconnell, Walter E. Godwin, Susan E. Baker, Kenya Powell, Martha Baskett, Amy Morara, Xiadong Ma
Journal of the Arkansas Academy of Science
The use of conductive polymers as a substitute for metallic conductors and semiconductors has attracted much attention in the literature. In particular, aromatic heterocyclic polymers constitute an important class since they possess chemical and electrical stability in both the oxidized (doped) and neutral (undoped) state. Doping a polymer allows one to vary its electrical, mechanical, optical, and thermal properties. The properties of these polymers are promising for their many technological uses such as antistatic coatings, solar cells, and electronic devises. Polyfuran is among the least common heterocyclic polymers. Polyfuran has been reported to be much less stable that either polypyrrole …
Modeling Of Electrofusion Coils For Performance Optimization, Steve Farmer, Robert A. Sims
Modeling Of Electrofusion Coils For Performance Optimization, Steve Farmer, Robert A. Sims
Journal of the Arkansas Academy of Science
Modeling physical parameters provides a virtual design environment allowing the confirmation and optimization of electrofusion characteristics. Finite element incorporate physical parameters and their interactions along common boundaries defined within a model geometry. The electrofusion of polymeric piping is a widely accepted means of assembling piping systems with zero-leakage integrity. The key parameters in the fusion process are the coil resistance, the current passing through the coil and the time the current is applied. Modeling the coil and applying current to the model is accomplished using the MATLABpartial differential equations (PDE) toolbox. This paper presents the method of modeling and the …
Improved Methods For Electroplating Cadmium Sulfide Thin Films, Brandon Kemp, Robert Engelken, Arif Raza, Wasim Aleem, Imran Khan, Chris Barber
Improved Methods For Electroplating Cadmium Sulfide Thin Films, Brandon Kemp, Robert Engelken, Arif Raza, Wasim Aleem, Imran Khan, Chris Barber
Journal of the Arkansas Academy of Science
We report improved methods for electroplating cadmium sulfide (CMS) films. Aprevious problem was cracking/flaking of films deposited from organic solutions of elemental sulfur; attempts to improve adhesion via bath additives reduced grain size. Aqueous baths of thiosulfate ions yield cadmium-richness at low T temperatures (T), long deposition times, and/or poor bath stability. Developments in our work to be discussed include (1) plating ofuniform, adherent, and stoichiometric CdS from tetraethylene baths of CdCl 2 and elemental sulfur at T >70° C with minimal cracking/flaking, (2) improved uniformity/ adherence by use of CdL>, and (3) swept voltage methods in aqueous thiosulfate …
Characterization Of Cadmium Sulfide Films Deposited By Chemical Bath Method, Quazi Galib Samdami, Hameed A. Naseem, W. D. Brown
Characterization Of Cadmium Sulfide Films Deposited By Chemical Bath Method, Quazi Galib Samdami, Hameed A. Naseem, W. D. Brown
Journal of the Arkansas Academy of Science
Thin filmcadmium sulfide is a leading candidate in the fabrication of large area solar cells. The chemical bath deposition method is one of the least expensive sources for the fabrication of device quality cadmium sulfide thin films.Inthe present work, the deposition of CdS films on glass substrate from an aqueous solution containing cadmium acetate, ammonia, ammonium acetate, and thiourea are investigated. The structural properties of CdS films are characterized. Good quality thin films within 0.1 - o.5 |im thickness were obtained in30 minute deposition time, and at 70*-90*C. The films show preferential orientations. The optical transmittance of the films are …
Diagnostics Of Cdte Electrodeposition By Rest Potential Voltammetry, Brandon Kemp, Robert Engelken, Arif Raza, Arees Siddiqui, Omer Mustafa
Diagnostics Of Cdte Electrodeposition By Rest Potential Voltammetry, Brandon Kemp, Robert Engelken, Arif Raza, Arees Siddiqui, Omer Mustafa
Journal of the Arkansas Academy of Science
Due to the extreme sensitivity of the partial elemental currents (i.e.,iCd, iTe) and, hence, stoichiometry to deposition voltage, temperature, mass transport, and ambient light intensity during electrodeposition of semiconductor films, it is important to implement in-situ methods for monitoring the stoichiometry and related semiconductor efficacy of the growing film. We report investigation of open circuit rest potential (Eoc) voltammetry as one such method during electrodeposition of CdTe from aprotic electrolytes such as ethylene glycol. Plots of transient open circuit potential versus sweep voltage exhibit distinct transition and plateau structures corresponding to Te, CdTe, and Cd phases and correlating with the …
Polishing Of Cvd-Diamond Substrates Using Reactive Ion Etching, Gopi M.R. Sirineni, Hameed A. Naseem, W. D. Brown, A. P. Malshe
Polishing Of Cvd-Diamond Substrates Using Reactive Ion Etching, Gopi M.R. Sirineni, Hameed A. Naseem, W. D. Brown, A. P. Malshe
Journal of the Arkansas Academy of Science
Multichip modules (MCM)have proved to be a viable packaging technology for achieving small size and high performance. By their nature, MCMs typically integrate multiple bare die into a module that can be the plastic or ceramic package. As a result, the MCMrequires an efficient mechanism for removing excess heat. Diamond with its excellent thermal conductivity, is the ideal choice as a substrate material for these applications. Chemical vapor deposited (CVD) diamond substrates makes possible the practical realization of a novel diamond based 3-D MCM. However, the diamond films grown by CVD technique are polycrystalline and have non-uniform filmroughness and randomly …
Using The Cern Program-Library Graphics And Interactive Data Display, Morgan T. Burks, Wilson H. Howe, Christine A. Byrd, Wilfred J. Braithwaite
Using The Cern Program-Library Graphics And Interactive Data Display, Morgan T. Burks, Wilson H. Howe, Christine A. Byrd, Wilfred J. Braithwaite
Journal of the Arkansas Academy of Science
Small scale Monte Carlo programming is growing rapidly due to the ease with which complex problems may be formulated by any programmer. These programmers may choose to exploit graphics and interactive displays available in the program library developed and maintained by CERN (the Center for European Nuclear Research). This paper outlines the use of graphics and interactive data display features of the CERN program library, developed for visualizing simulated data events in particle detectors. One example uses GEANT, CERN's Monte Carlo modeling program, to simulate 300 MeV/c protons incident on a silicon slab. Display packages for GEANT are available both …
Comparison Of High-Temperature Superconductors In Multi-Chip Module Applications, D. E. Ford, S. S. Scott, S. S. Ang, W. D. Brown
Comparison Of High-Temperature Superconductors In Multi-Chip Module Applications, D. E. Ford, S. S. Scott, S. S. Ang, W. D. Brown
Journal of the Arkansas Academy of Science
In the application of high-temperature superconductors (HTSCs) in multi-chip module (MCM) technology, it is first necessary to investigate the advantages and disadvantages of the various HTSC compounds. The standard criteria for comparing the suitability of HTSCs in electronics applications has been critical temperature (Tc )and critical current density (Jc ). It is also necessary to consider the physical properties of HTSCs in relation to the various processing techniques required in fabrication of MCMs. These techniques can be grouped into four main areas: deposition, patterning, packaging, and characterization. The four main HTSC materials, Y-Ba-Cu-O, Bi-Sr-Ca-Cu-O, Tl,Ba-Ca-Cu-O and Hg-Ba-Ca-Cu-O, will be compared …
Gamma Ray Emissions From Binary Pulsar Systems, Tony A. Hall, Andrew T. Sustich
Gamma Ray Emissions From Binary Pulsar Systems, Tony A. Hall, Andrew T. Sustich
Journal of the Arkansas Academy of Science
A method is developed for estimating the gamma ray flux impinging upon the earth from production in binary pulsar systems. We calculate production of the 6.13 MeV gamma ray line characteristic of 16O. These are produced by protons emitted by the pulsar interacting with 16O atoms at the surface of the companion. We examine different types of companion stars and estimate the gamma ray flux at the earth as a function of proton emission from the pulsar and distance from the earth. Prospects for detection from earth are discussed.
Sputter Deposition And Thallination Of Ti-Ba-Ca-Cu-O Superconducting Thin Films, T. H. Dhayagude, S. S. Ang, W. D. Brown
Sputter Deposition And Thallination Of Ti-Ba-Ca-Cu-O Superconducting Thin Films, T. H. Dhayagude, S. S. Ang, W. D. Brown
Journal of the Arkansas Academy of Science
Thallination techniques used for the fabrication of sputter-deposited TI2Ba2CaCu 2Ox and TI2Ba2Ca2Cu3Ox superconducting thin films were investigated. Differences in elemental composition of precursor Ba-Ca-Cu-O sputtering targets were found to yield different superconducting phases. Thallination conditions which yielded transition temperatures as high as 122 K for samples annealed in air are described. Finally, reactive ion etching of films using a mixture of chlorine and argon gases is discussed.
Multiple Sample Cryostat For The Determination Of Superconductor Properties, G. Burnside, Roger M. Hawk, Paul C. Mcleod
Multiple Sample Cryostat For The Determination Of Superconductor Properties, G. Burnside, Roger M. Hawk, Paul C. Mcleod
Journal of the Arkansas Academy of Science
Cryostats which are currently used to characterize the properties of superconductors between 4 K and 100 K are primarily single sample devices. The purpose of this paper is to present an instrument design which can hold up to five (5) one cm. diameter samples at a stable temperature (+ /-0.1K) within the above range specified while measurements of the sample properties are made.
Semi-Insulating Polysilicon Hetero- And Isotype Junctions On Silicon, R. M. Ranade, S. S. Ang, W. D. Brown
Semi-Insulating Polysilicon Hetero- And Isotype Junctions On Silicon, R. M. Ranade, S. S. Ang, W. D. Brown
Journal of the Arkansas Academy of Science
The effects of nitrogen trifluorideinthe gas stream during deposition of semi-insulating polysilicon (SIPOS) on the electrical characteristics of undoped (SIPSO)/p-Si, and n+-SIPOS/n-Si isotype junctions were investigated. The current-voltage characteristics of undoped SIPOS/p-Si heterojunctions exhibit a strong dependence on the oxygen content of the SIPOS film and depart from a hyperbolic sine behavior as the refractive index of the SIPOS increases.. The addition of nitrogen trifluoride decreases the current density of these undoped SIPOS/p-Si heterojunctions due presumably to the oxidation/hydrolysis of SiF species intoSiO2. The n+-SIPOS formed a rectifying isotype junction o n-Si. The forward current voltage characteristics exhibit two distinct …
Properties Of Ruthenium Oxide Coatings, Roger M. Hawk, Kamesh V. Gadepally, David N. Patangia
Properties Of Ruthenium Oxide Coatings, Roger M. Hawk, Kamesh V. Gadepally, David N. Patangia
Journal of the Arkansas Academy of Science
Ruthenium oxide coatings have been deposited on titanium substrates using a flood coating process. These films were heat treated for varying times and temperatures. The resulting films subsequently were characterized by performing resistivity and SEM analyses. Resistivity of the ruthenium oxide coating was found to be extremely dependent upon the firing temperature. Effect of the process conditions and formulations of the coatings on the morphology with respect to their electrical characteristics is presented. Capacitors were fabricated using plates coated with ruthenium oxide coatings. Capacitance versus heat treatment temperatures are discussed and at one firing temperature (480'C), the capacitance was 50 …
Data Acquisition And Control Program For Chromatography, M. Keith Hudson, William G. Hood
Data Acquisition And Control Program For Chromatography, M. Keith Hudson, William G. Hood
Journal of the Arkansas Academy of Science
No abstract provided.
Principles And Clinical Applications Of Magnetic Resonance, Rao P. Gullapalli, Teresa T. Evans, Roger M. Hawk
Principles And Clinical Applications Of Magnetic Resonance, Rao P. Gullapalli, Teresa T. Evans, Roger M. Hawk
Journal of the Arkansas Academy of Science
A review is presented which covers the basic theory of nuclear magnetic resonance (NMR) with regard to angular momentum, magnetic moments, and the classical mechanical description of the NMR experiment. Longitudinal (T,) and Transverse (T2) relaxation times are defined as well as the basic pulse sequences used for their measurement. In particular, the 180°-t-90° and the Hahn Spin Echo pulse sequences are described in detail. Basic Magnetic Resonance Imaging (MRI) theory is discussed with regard to slice selection, frequency encoding, and phase encoding to define the imaged volume element. The equations defining the amount of Tt , T2 , and …
Integrated Circuits Interconnect Metallization For The Submicron Age, Kamesh V. Gadepally, Roger M. Hawk
Integrated Circuits Interconnect Metallization For The Submicron Age, Kamesh V. Gadepally, Roger M. Hawk
Journal of the Arkansas Academy of Science
The interconnect metallization being used by the semiconductor industry has been aluminum or aluminum silicon. Aluminum silicon is being replaced by aluminum copper and aluminum copper silicon, due to its superior resistance to electromigration and hillock growth. This paper discusses the implementation of aluminum copper/silicon alloys in semiconductor processing, along with a review of the problems and advantages of the same.
Versatile Potentiostat With Optional Computer Control, Gary L. Fuller, William A. Russell Jr., Roger M. Hawk, James D. Wilson, P. D. Bratton
Versatile Potentiostat With Optional Computer Control, Gary L. Fuller, William A. Russell Jr., Roger M. Hawk, James D. Wilson, P. D. Bratton
Journal of the Arkansas Academy of Science
A versatile potentiostat which can supply a maximum of 125 ma is described. The potentiostat uses readily available electronic components and an interface is detailed which allows the potentiostat optional computer control.
Computer-Controlled Programmable Pulse Generator For A Jeol Jnm-Ft-1a Radio Frequency Amplifier Section Of A Nuclear Magnetic Resonance Spectrometer, William H. Russell, Roger M. Hawk
Computer-Controlled Programmable Pulse Generator For A Jeol Jnm-Ft-1a Radio Frequency Amplifier Section Of A Nuclear Magnetic Resonance Spectrometer, William H. Russell, Roger M. Hawk
Journal of the Arkansas Academy of Science
A microprocessor controlled programmable pulse generator was specifically designed to interface with the JEOL JNM-FT-1 A Radio Frequency (RF) section of a nuclear magnetic resonance (NMR) spectrometer. The programmable pulse generator was programmed and controlled by an IBM compatible computer. Statis rams were utilized as the programmable pulse generator's on board memory which were used to store the pulse sequences. Pulse widths can be programmed from 0.2 microseconds to 14.3 minutes. The JEOL RF section is unique in that it allows the pulse generator to control the phase of the RF transmitted to the NMR probe and whether the sample …
Image Processing Instrumentation For Giardia Lamblia Detection, Cy R. Tamanaha, Mark A. Gross
Image Processing Instrumentation For Giardia Lamblia Detection, Cy R. Tamanaha, Mark A. Gross
Journal of the Arkansas Academy of Science
Currently, the identification and enumeration of Giardia Iamblia cysts are based upon microscopic methods requiring individuals proficient in this area. It is a tedious process which consumes time that could be constructively used elsewhere. This project attempts to alleviate that burden by employing a computer to automatically process Indirect Fluorescent Antibody (IFA) prepared slides using digital image processing techniques. A computer controlled frame grabber, in conjunction with a CCD TV camera mounted on the epi-fluorescence microscope phototube, captures the light intensities of the objects in view under the microscope objective. The captured image is stored as pixels, with each pixel …
Application Of Geligam Software To The Analysis Of X-Ray Spectra, R. S. Saunders, Harold L. Pray, H. B. Eldridge
Application Of Geligam Software To The Analysis Of X-Ray Spectra, R. S. Saunders, Harold L. Pray, H. B. Eldridge
Journal of the Arkansas Academy of Science
No abstract provided.
Random Wave Form Generator, Zaboj V. Harvalik
Random Wave Form Generator, Zaboj V. Harvalik
Journal of the Arkansas Academy of Science
No abstract provided.