Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Electrical and Computer Engineering (620)
- Physical Sciences and Mathematics (619)
- Civil and Environmental Engineering (429)
- Biomedical Engineering and Bioengineering (425)
- Chemical Engineering (425)
-
- Mechanical Engineering (299)
- Life Sciences (288)
- Materials Science and Engineering (284)
- Civil Engineering (281)
- Operations Research, Systems Engineering and Industrial Engineering (260)
- Medicine and Health Sciences (213)
- Computer Engineering (207)
- Industrial Engineering (206)
- Social and Behavioral Sciences (202)
- Nanoscience and Nanotechnology (181)
- Power and Energy (175)
- Electrical and Electronics (160)
- Environmental Sciences (159)
- Computer Sciences (149)
- Physics (136)
- Bioresource and Agricultural Engineering (134)
- Electronic Devices and Semiconductor Manufacturing (132)
- Education (128)
- Structural Engineering (113)
- Molecular, Cellular, and Tissue Engineering (111)
- Transportation Engineering (106)
- Earth Sciences (101)
- Operational Research (98)
- Chemistry (95)
- Keyword
-
- Applied sciences (345)
- Pure sciences (63)
- Engineering (40)
- Simulation (33)
- Service learning (27)
-
- Sustainability (26)
- Machine Learning (25)
- Machine learning (25)
- Power electronics (25)
- Biological sciences (24)
- Optimization (23)
- Concrete (22)
- Nanoparticles (20)
- Silicon carbide (20)
- Arkansas (18)
- Earth sciences (18)
- Graphene (18)
- Optoelectronics (18)
- Transportation (17)
- Fatigue (16)
- Plasmonics (16)
- Power Electronics (16)
- Asynchronous (15)
- Modeling (15)
- Social sciences (15)
- Asphalt (14)
- Deep learning (14)
- Reliability (14)
- Silicon Carbide (14)
- Additive Manufacturing (13)
- Publication Year
- Publication
-
- Graduate Theses and Dissertations (1219)
- Chemical Engineering Undergraduate Honors Theses (228)
- Journal of the Arkansas Academy of Science (175)
- Biomedical Engineering Undergraduate Honors Theses (156)
- Mechanical Engineering Undergraduate Honors Theses (148)
-
- Biological and Agricultural Engineering Undergraduate Honors Theses (106)
- Civil Engineering Undergraduate Honors Theses (92)
- Electrical Engineering Undergraduate Honors Theses (90)
- Industrial Engineering Undergraduate Honors Theses (88)
- Computer Science and Computer Engineering Undergraduate Honors Theses (65)
- Biomedical Engineering Faculty Publications and Presentations (49)
- Chemical Engineering Faculty Publications and Presentations (43)
- Biological and Agricultural Engineering Faculty Publications and Presentations (36)
- Mechanical Engineering Faculty Publications and Presentations (29)
- Electrical Engineering Faculty Publications and Presentations (26)
- Electrical Engineering and Computer Science Faculty Publications and Presentations (25)
- Inquiry: The University of Arkansas Undergraduate Research Journal (25)
- Operations Management Presentations (25)
- Physics Faculty Publications and Presentations (23)
- Computer Science and Computer Engineering Faculty Publications and Presentations (22)
- Electrical Engineering and Computer Science Undergraduate Honors Theses (21)
- Civil Engineering Faculty Publications and Presentations (19)
- 2026 Research Poster Competition (18)
- Chemistry & Biochemistry Faculty Publications and Presentations (12)
- 2025 Research Poster Competition (9)
- Data Science Undergraduate Honors Theses (9)
- Industrial Engineering Faculty Publications and Presentations (9)
- Physics Undergraduate Honors Theses (7)
- Biological Sciences Undergraduate Honors Theses (6)
- High School Lesson Plans (4)
- Publication Type
- File Type
Articles 2761 - 2790 of 2828
Full-Text Articles in Engineering
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.
The Need For Pfc Abatement In Semiconductor Manufacturing, Mohsen Manesh, Brian Kendrick
The Need For Pfc Abatement In Semiconductor Manufacturing, Mohsen Manesh, Brian Kendrick
Inquiry: The University of Arkansas Undergraduate Research Journal
Perfluorocompounds (PFCs) are highly stable chemical compounds used in two integral steps of semiconductor manufacturing: chemical vapor deposition (CVD) chambers and etch chambers. Unfortunately, PFCs are also greenhouse gases linked to global warming. This, combined with their long atmospheric lifetimes gives them global warming potentials much higher than C02 the principal greenhouse gas. In a series of voluntary agreements with the United States and other national governments, the worldwide semiconductor industry has set a goal of reducing PFC emissions to 90% of their 1995 levels. To reach this goal, researchers have explored four main methods of reduction: substitution of PFCs, …
Extraction Of Silymarin Compounds From Milk Thistle (Silybum Marianum) Seed Using Hot, Liquid Water As The Solvent, J.F. Alvarez Barreto
Extraction Of Silymarin Compounds From Milk Thistle (Silybum Marianum) Seed Using Hot, Liquid Water As The Solvent, J.F. Alvarez Barreto
Inquiry: The University of Arkansas Undergraduate Research Journal
High value specialty chemicals are usually obtained from natural products by extracting with generally regarded as safe (GRAS) solvents. Because organic solvents are quite often used, high operating and disposal costs often occur. When compared to traditional solvents, water can be viewed as an interesting alternative because of its low operating and disposal costs. Milk thistle contains compounds (taxifolin, silychristin, silydianin, silybinin A and silybinin B) that display hepatoxic protection properties. This paper examines the batch extraction of silymarin compounds from milk thistle seed meal in 50'C, 70'C, 85'C and 100'C water as a function of time. For taxifolin, silychristin, …
Stability And Optimization Of Photoconductivity In Thermally Vacuum Evaporated Indium (Iii) Sulfide Thin Films, Gustavo Rehder, Robert Engelken, Randy Stidham, Richard Tanner, Lee Ketchum, Anil Baral
Stability And Optimization Of Photoconductivity In Thermally Vacuum Evaporated Indium (Iii) Sulfide Thin Films, Gustavo Rehder, Robert Engelken, Randy Stidham, Richard Tanner, Lee Ketchum, Anil Baral
Journal of the Arkansas Academy of Science
Long term stability of photosensitivity versus time in indium (III) sulfide thin films thermally vacuum evaporated onto photocell-patterned printed circuit boards varies sensitively with several factors including contact metal type, contact metal diffusion and electromigration into the semiconductor, doping, and encapsulation method. Because of the significant photoconductivity and relative low toxicity and environmental impact of this compound semiconductor, it is important to better characterize these dependences toward commercial applications. We will report on measurements of photoconductivity vs. time as functions of such factors and evolving methods to stabilize this photoconductivity.
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 …
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 …
Pressure And Flow Validation Of A Second Generation Gas Extraction Probe For A Hybrid Rocket Gas Extraction System, Constance Meadors, Andrew B. Wright
Pressure And Flow Validation Of A Second Generation Gas Extraction Probe For A Hybrid Rocket Gas Extraction System, Constance Meadors, Andrew B. Wright
Journal of the Arkansas Academy of Science
A gas extraction system (GES) has been designed for use with the hybrid rocket facility at the University of Arkansas at Little Rock (UALR) for spectroscopic analysis of rocket plumes. While monitoring gas flow-rate and pressure, the GES extracts gases from the hybrid rocket plume and transports them to a mass spectrometer. This paper describes design and construction of a gas extraction probe (GEP) prototype capable of extracting gases directly from the plume. Gas dynamics equations were used to design two venturi-type GEP, converging and converging-diverging. The probe was tested with air to verify design assumptions. Flow rate through the …
A Method Of Implementing The Interleaver In 3g Wireless Communication Systems For Randomization Of Burst Errors, Eric Duquette
A Method Of Implementing The Interleaver In 3g Wireless Communication Systems For Randomization Of Burst Errors, Eric Duquette
Inquiry: The University of Arkansas Undergraduate Research Journal
In less than a year or two, third generation ( 3G) wireless communication systems will be replacing the currently existing second generation (2G) wireless systems and be used worldwide. The 3G systems will have a higher data transfer capacity, which allows for simultaneous data, voice, and video transfer (e.g., multimedia applications) while most of 2G systems only allow for low-rate data and voice transfer. The wireless communications industry has set standards for 3G, which detail various operations of the technology. It should be noted that the 3G standards outline only the different operations and not the processes for the production …
Analysis Of Wireless Networking On The University Of Arkansas Campus, Julia Lincoln
Analysis Of Wireless Networking On The University Of Arkansas Campus, Julia Lincoln
Inquiry: The University of Arkansas Undergraduate Research Journal
Wireless communication has already begun to change the way business and research is done today. Development of the wireless network for digital cellular phone has already improved the area of voice communications. The area of portable and mobile connectivity for computers and other devices is beginning to emerge. The research analyzes and compares a few of these wireless networks. Physical aspects such as range, interference factors, and frequency capabilities and restrictions are assessed. Capacity analysis including round trip times, latency, and throughput are done as well. Issues of authentication and addressing protocols are researched to determine optimal performance and convenience …
Field Interpretation Of Latitude And Longitude In Arkansas: A Portable Coordinate Projection, William R. Teague
Field Interpretation Of Latitude And Longitude In Arkansas: A Portable Coordinate Projection, William R. Teague
Journal of the Arkansas Academy of Science
Two- and three-dimensional coordinate systems are fundamental to most quantitative mapping applications. The Geodetic, Universal Transverse Mercator (UTM),and State Plane systems have traditional roles in various science, surveying, and government agency engineering applications. The coordinates of three-dimensional Geodetic system are latitude, longitude, and height above ellipsoid (HAE).Because of its ability to cope with the intrinsically three dimensional character of the earth's surface, the Geodetic system is capable of supporting precise relative positioning and very high accuracy computations of distance between any two positions on or near the earth's surface. The two-dimensional UTMand State Plane systems are extremely useful for the …
Mechatronic Design Of A Treaded Mobile Robot For Mine Sweeping, Andrew B. Wright
Mechatronic Design Of A Treaded Mobile Robot For Mine Sweeping, Andrew B. Wright
Journal of the Arkansas Academy of Science
Autonomous mobile robots, which can be programmed to exhibit cooperative behaviors, are ideal mechanisms for sweeping land mines. They can spread out to hunt for the mines, using a dispersal rule. Once a mine is located, they can congregate to surround it using a clustering rule. Should a robot be destroyed by tripping an unseen mine, the cost is minimal compared to a human life. UALR has been experimenting with coupled oscillator based rule generators for several years using fragile, indoor robots in a laboratory setting to validate the clustering and dispersal behaviors. In order to accomplish outdoor trials, a …
Derivation Of Equations Of Motion For A Four Link Robotic Leg For A Walking Vehicle, Andrew B. Wright
Derivation Of Equations Of Motion For A Four Link Robotic Leg For A Walking Vehicle, Andrew B. Wright
Journal of the Arkansas Academy of Science
A four degree of freedom leg for a walking robot has been modeled using Newton's method. Unlike robot manipulators, which have a fixed base, a leg model must include inertial forces due to base motion. These forces have been included in the formulation. These equations can be used for design, simulation, and control. The inverse kinematics for this leg are also presented. This allows the joint angles to be computed from a desired foot-hold position.
Thin Film Deposition Of Silicon For Solar Cell Applications, Sailesh Kumar, Roger M. Hawk
Thin Film Deposition Of Silicon For Solar Cell Applications, Sailesh Kumar, Roger M. Hawk
Journal of the Arkansas Academy of Science
Thin films of silicon have been formed using a patented electrostatic deposition method which utilizes charged particle motion in an electric field. After deposition, the films are heat treated for varying times and temperatures in a programmable furnace maintained under a purified argon atmosphere. X-ray diffraction (XRD) confirmed that these films were polycrystalline in nature. These films were found to have grain sizes of about 50 microns. Solar cells were fabricated using these large grained polycrystalline silicon films by sputtering pure gold as both front and back contacts. The cells have shown efficiencies of 1.8%. This paper reports on the …
Preparation Of Powder Precursors And Evaporation Of Photoconductive Indium Sulfide Films, Chris Barber, Robert Engelken, Brandon Kemp, Wasim Aleem, Imran Khan, Chris Edrington, Michael Buck, Clayton Workman, Anup Thapa, Tom Jakobs
Preparation Of Powder Precursors And Evaporation Of Photoconductive Indium Sulfide Films, Chris Barber, Robert Engelken, Brandon Kemp, Wasim Aleem, Imran Khan, Chris Edrington, Michael Buck, Clayton Workman, Anup Thapa, Tom Jakobs
Journal of the Arkansas Academy of Science
We have demonstrated significant photoconductance in indium sulfide thin films prepared by thermal vacuum evaporation ofIn2$3 powders synthesized in-house by chemical precipitation ofInCl3 or In(CH3COO)3, and (NH4)2S or Na2S. The Delta G lambda/Gdark values have been as high as 0.1 in the initial unoptimized films. Excess sulfur (via a mixture of polysulfide and sulfide ions in the synthesis bath) appears to be important in achieving reproducible and large photoconductivities. In2S3 is particularly attractive as a lower toxicity alternative to CdS in optoelectronic applications such as photovoltaic and photoconductive cells.
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 …
Electrodeposition Of Copper Indium Sulfide Films From Organic Solutions, Arif Raza, Robert Engelken, Brandon Kemp, Imran Khan, Wasim Aleem, Chris Barber
Electrodeposition Of Copper Indium Sulfide Films From Organic Solutions, Arif Raza, Robert Engelken, Brandon Kemp, Imran Khan, Wasim Aleem, Chris Barber
Journal of the Arkansas Academy of Science
We report on organic solutions ofCuCl 2 ,InClg, and elemental sulfur for electrodepositing CuIn x Sv films. CuInS 2 and CuInSe 2 are promising solar cellmaterials; our work on CuInSg prefaces planned work on plating CuInSe 2 from nonaqueous solvents. Two promising solvent systems are (1) mixed propylcne carbonate and water and (2) mixed ethylene glycol, propionic acid, and water (Engelken et al., 1988). Gray-brown films ofCuInx Sy (nominally GuInS2 ) have been plated from both baths. Major problems include (1) reduction ofCu+2 to Cu and Cu x S by the solvent at high temperatures (T>l()0°C), hence depleting Cu+2,(2) …
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 …
Molten Salt Electrolytes For Electrodeposition Of Cdte Films, Arif Raza, Robert Engelken, Brandon Kemp, Arees Siddiqui, Omer Mustafa
Molten Salt Electrolytes For Electrodeposition Of Cdte Films, Arif Raza, Robert Engelken, Brandon Kemp, Arees Siddiqui, Omer Mustafa
Journal of the Arkansas Academy of Science
We report preliminary investigation of several molten salt electrolytes containing CdCl2 and TeCl4 for the electrodeposition of CdTe films at temperatures well above (>250 °C) those used with aqueous and organic electrolytes. These high temperatures have potential todramatically increase the crystallite size (Poole, Engelken, et al., 1994), as is important for optoelectronic device applications of CdTe, a leading II-VIsemiconductor. This paper willsurvey the results obtained withelectrolytes such as B2O,/HBO2 (m.p. - 230'C), NaCH3COO (m.p. » 324°C), ZnCl2 (m.p. - 283*C), and LiCl/KCl (m.p. * 350 °C), with an emphasis on the latter two. Key material to be presented includes …
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 …
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 …
Construction Resource Allocation Using A Genetic Algorithm, Siripong Malasri, Jennifer R. Martin
Construction Resource Allocation Using A Genetic Algorithm, Siripong Malasri, Jennifer R. Martin
Journal of the Arkansas Academy of Science
A proper allocation of limited resources (men, machines, materials, and money) is critical in a construction project. Traditionally, resource allocation problems have been solved using methods in operations research (OR), such as mathematical programming. In recent years, genetic algorithms (GA) have emerged as an effective optimization methodology. One major advantage of the GA approach over the OR approach is that the GA approach is universal for various types of optimization problems, unlike the OR approach which varies depending on the types of problems at hand. This paper shows an application of GA to a resource allocation problem in the construction …
Retrieval Of Atmospheric Turbidity Coefficiant And Water Column Density Fro Solar Irradiance Data, Felix Tendeku
Retrieval Of Atmospheric Turbidity Coefficiant And Water Column Density Fro Solar Irradiance Data, Felix Tendeku
Journal of the Arkansas Academy of Science
Ground-based measurement of solar irradiance has been made using a spectroradiometer at wavelengths inapx-water absorption band. An algorithm is formulated to retrieve simultaneously the atmospheic water column density and Angstrom's turbidity coefficient. The transmission models used to account for the contribution from diverse atmospheic absorbing and scattering elements are presented.
Concrete Beam Design Optimization With Genetic Algorithms, Siripong Malasri, D. A. Halijan, M. L. Keough
Concrete Beam Design Optimization With Genetic Algorithms, Siripong Malasri, D. A. Halijan, M. L. Keough
Journal of the Arkansas Academy of Science
This paper demonstrates an application of the natural selection process to the design of structural members. Reinforced concrete beam design is used as the example to show how various chromosomes representing a design solution can be formulated. Fitter chromosomes (or better solutions) have a better chance of being selected for cross over; this in turn creates better generations. Random mutation is used to enhance the diversity of the population. The evolution progresses through several generations, and the best solution is then used in the design. The method gives reasonable results, but sometimes a local (as opposed to the global) optimized …
Application Of Machine Learning Principles To Modeling Of Nonlinear Dynamic Systems, Murray R. Clark
Application Of Machine Learning Principles To Modeling Of Nonlinear Dynamic Systems, Murray R. Clark
Journal of the Arkansas Academy of Science
A method for the development of mathematical models for dynamic systems with arbitrary nonlinearities from measured data is described. The method involves the use of neural networks as embedded processors in dynamic system simulation models. The technique is demonstrated through generation of models for anharmonic oscillators described by the Duffing Equation and the Van der Pol Equation from measured input/output data. It is shown that high quality models of these systems can be developed using this technique which are efficient in terms of model size. Using neural networks as embedded processors, accurate models of the Duffing Oscillator and the Van …
Method For Determining Atmospheric Aerosol Optical Depth Using Solar Transmission Measurements, Felix Tendeku
Method For Determining Atmospheric Aerosol Optical Depth Using Solar Transmission Measurements, Felix Tendeku
Journal of the Arkansas Academy of Science
A multiple wavelength radiometer instrumentation has been developed and used to measure solar irradiance in a water vapor absorption band in the near-infrared region. From these measurements the total atmospheric optical depth at each wavelength of observation is deduced using a linear least-squares fitting method. An iteration technique, based on a power law wavelength dependence of aerosol optical depth, is employed to retrieve aerosol optical depth from the total optical depth data. The technique permits simultaneous determination of precipitable water vapor amount.
Solid State Nmr Of Hydrogen In Thin Film Synthetic Diamond, G. Burnside, Roger M. Hawk, Richard A. Komoroski, W. D. Brown
Solid State Nmr Of Hydrogen In Thin Film Synthetic Diamond, G. Burnside, Roger M. Hawk, Richard A. Komoroski, W. D. Brown
Journal of the Arkansas Academy of Science
Thin film synthetic diamond promises to be the next semiconductor material, if the manufacturing processes which produce it can be controlled. Solid state nuclear magnetic resonance (NMR) using magic angle spinning (MAS) is used to measure the content of hydrogen in diamond which controls the resistivity of the diamond thin films. Spectral results are presented for proton NMR of thin film synthetic diamond. Experimental calibration techniques using BaF2 as the hydrogen standard will be discussed, as well as acquisition times, pulsing sequences, spinning rates, and rotor composition.
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 …
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 …