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1998

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Articles 391 - 420 of 2339

Full-Text Articles in Physical Sciences and Mathematics

Water Balloon Rupture In Low‐G, Mark M. Weislogel, S. Lichter Sep 1998

Water Balloon Rupture In Low‐G, Mark M. Weislogel, S. Lichter

Mechanical and Materials Engineering Faculty Publications and Presentations

A qualitative study of the bursting of water balloons in a simulated low-gravity environment was conducted aboard NASA Lewis’s DC-9 aircraft.

The tests were performed to develop techniques to rapidly deploy large liquid drops in a microgravity environment.


The Sharp Sobolev Inequality And The Banchoff-Pohl Inequality On Surfaces, Ralph Howard Sep 1998

The Sharp Sobolev Inequality And The Banchoff-Pohl Inequality On Surfaces, Ralph Howard

Faculty Publications

No abstract provided.


A Resource Allocation Mechanism Based On Cost Function Synthesis In Complex Systems, Carlos C. Amaro Aug 1998

A Resource Allocation Mechanism Based On Cost Function Synthesis In Complex Systems, Carlos C. Amaro

Dissertations

While the management of resources in computer systems can greatly impact the usefulness and integrity of the system, finding an optimal solution to the management problem is unfortunately NP hard. Adding to the complexity, today's 'modern' systems - such as in multimedia, medical, and military systems - may be, and often are, comprised of interacting real and non-real-time components. In addition, these systems can be driven by a host of non-functional objectives – often differing not only in nature, importance, and form, but also in dimensional units and range, and themselves interacting in complex ways. We refer to systems exhibiting …


Microwave Heating Of Fluid/Solid Layers : A Study Of Hydrodynamic Stability And Melting Front Propagation, John Gilchrist Aug 1998

Microwave Heating Of Fluid/Solid Layers : A Study Of Hydrodynamic Stability And Melting Front Propagation, John Gilchrist

Dissertations

In this work we study the effects of externally induced heating on the dynamics of fluid layers, and materials composed of two phases separated by a thermally driven moving front. One novel aspect of our study is in the nature of the external source, which is provided by the action of microwaves acting on dielectric materials. The main challenge is to model and solve systems of differential equations, which couple fluid dynamical motions (the Navie- Stokes equations for nonisothermal flows) and electromagnetic wave propagation (governed by Maxwell's equations).

When an electromagnetic wave impinges on a material, energy is generated within …


Emissivity Measurements And Modeling Of Silicon Related Materials And Structures, Sufian Abedrabbo Aug 1998

Emissivity Measurements And Modeling Of Silicon Related Materials And Structures, Sufian Abedrabbo

Dissertations

The objective of this dissertation is to investigate the major issues concerning applications of pyrometry for applications in rapid thermal processing (RTP) of silicon related materials. The research highlights of this work are:

Establishment of spectral ernissometry as a novel, reliable and reproducible technique for:

Determination of wavelength and temperature dependent reflectivity, transmissivity, emissivity and temperature, simultaneously, of silicon related materials and structures. The emissometer operates in the wavelength range of 1-20mm and temperature range of 300-1200K. The analysis of the influence of morphological effects on the radiative properties by measurement of (a) front-smooth incidence versus backside-rough incidence of singleside …


A Folder Organization Model For Information Systems : Exploring Its Architectural Expressive Power And Predicate-Based Filing, Simon Doong Aug 1998

A Folder Organization Model For Information Systems : Exploring Its Architectural Expressive Power And Predicate-Based Filing, Simon Doong

Dissertations

This dissertation presents an Internal Folder Organization (I-ORG) which supplements the architectural deficiencies of the existing model - the User Folder Organization (U-ORG), to electronically model a person's filing system in the modern office environment. An I-ORG folder organization gives a logical representation of how documents of the same or different kinds are related and grouped into folders based on predefined premises. Our model is represented by a Rooted Direct Acyclic Graph (RDAG). Each node in the graph represents a folder; and folders are related by "subfolder relationship" (for capturing the "and" relation) and "virtual-folder relationship" (for capturing the "or" …


A Graph Based Process Model Measurement Framework Using Scheduling Theory, Gary Guang-Li Mou Aug 1998

A Graph Based Process Model Measurement Framework Using Scheduling Theory, Gary Guang-Li Mou

Dissertations

Software development processes, as a means of ensuring software quality and productivity, have been widely accepted within the software development community; software process modeling, on the other hand, continues to be a subject of interest in the research community. Even with organizations that have achieved higher SEI maturity levels, processes are by and large described in documents and reinforced as guidelines or laws governing software development activities. The lack of industry-wide adaptation of software process modeling as part of development activities can be attributed to two major reasons: lack of forecast power in the (software) process modeling and lack of …


Observation Of High Momentum Η′ Production In B Decays, T. E. Browder, Kenneth A. Bloom, Cleo Collaboration Aug 1998

Observation Of High Momentum Η′ Production In B Decays, T. E. Browder, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

We report the first observation of B→ η′X transitions with high momentum η′ mesons. We observe 39.0 ± 11.6 B decay events with 2.0 < Pη′ < 2.7 GeV/c, the high momentum region where background from b → c processes is suppressed. We discuss the physical interpretation of the signal, including the possibility that it is due to b → sg* transitions. Given that interpretation, we find Ɓ(B →η′Xs) = [6.2 ± 1.6(stat) ± 1.3(syst) -1.5+0.0(bkg)] X 10-4 for 2.0 < Pη′ < 2.7 GeV/c.


Competition Of Copper, Lead, And Cadmium Adsorption To Goethite, Chris A. Christophi Aug 1998

Competition Of Copper, Lead, And Cadmium Adsorption To Goethite, Chris A. Christophi

Theses

Competition of copper, lead, and cadmium adsorption on goethite depends on metal ion and oxide surface characteristics. Goethite was characterized via X-ray diffraction, potentiometric titrations, site density determination, particle size analysis, and optical microscopy. In this thesis, a hypothesis was tested that electronegativity is the most important factor in metal affinities and adsorption competition to goethite.

Metal affinity and site density for the goethite surface were assessed by performing adsorption edges and isotherms. Based on the results of these experiments, competition studies were designed to observe adsorption and displacement of the competing metals by limiting the number of available sites …


Requirement Elicitation And Knowledge Management Utilizing Relational Database, Client Server And Internet Technologies, Umang J. Dave Aug 1998

Requirement Elicitation And Knowledge Management Utilizing Relational Database, Client Server And Internet Technologies, Umang J. Dave

Theses

The first step in any project is a statement of requirements. Requirements specification is an inevitable part of any successful project. However, the "rush" to convert concepts to products often proves as a big hindrance in the development process of any requirements set. This, in turn, hampers the ability to produce the concept and manage knowledge as originally envisioned.

The goal of the thesis is to foster understanding among the different communities affected by the development of the given system. The thesis is based on the principle that the requirements elicitation process for complex system is fundamentally a conversation among …


Process Modeling Using Proslcse On Web-Enabled Platform, Orcan Ali Enunlu Aug 1998

Process Modeling Using Proslcse On Web-Enabled Platform, Orcan Ali Enunlu

Theses

Process modeling is a relatively complex task that needs to be addressed from a different point of view. The classical approach would be to design the model, to send it for evaluation, then to return feedback to the developing team, and to reevaluate the model with the feedback received from the parties involved.

However, it is our understanding that the steps taken during the process modeling could benefit from the advantages that the Internet offers. To demonstrate the usefulness of Internet in process modeling, I have taken an existing tool, ProSLCSE, and implemented it with Java so that it can …


Determination Of Electron Donors In The Reductive Dechlorination Of Tetrachloroethene, Samantha L. Marasigan-Bernal Aug 1998

Determination Of Electron Donors In The Reductive Dechlorination Of Tetrachloroethene, Samantha L. Marasigan-Bernal

Theses

Several substrates, namely fatty acids and alcohols, were used to enhance the reductive microbial dechlorination of PCE to ethene. All of the microcosms amended with the volatile fatty acids (butyrate, succinate, lactate, formate, butyrate/formate mixture and butyrate/succinate mixture) demonstrated complete reductive dechlorination of PCE to ethane. The cultures amended with the butyrate/succinate mixture was the quickest to completely dechlorinate PCE to ethene (49 days). Those amended with butyrate, succinate, formate and the butyrate/formate mixture exhibited complete reductive, dechlorination at 77 days. Microcosms amended with lactate exhibited complete reductive dechlorination at 160 days.

The microcosms amended with the alcohols (ethanol, propanol, …


Development And Field Testing Of Pulse Introduction Membrane Extraction (Pime) For Measurement Of Ground Water Contamination, Anthony San Juan Aug 1998

Development And Field Testing Of Pulse Introduction Membrane Extraction (Pime) For Measurement Of Ground Water Contamination, Anthony San Juan

Theses

VOCs are a class of aromatic and aliphatic compounds with a variety of functional groups, and are in general detrimental to human health even at trace levels. Conventional analysis of VOCs in groundwater usually involves sampling at site followed by laboratory analysis. This results in long turn around times, high cost and also errors associated with sample preservation during transportation and storage. In order to address these problems, a field portable instrument referred to as Pulse Introduction Membrane Extraction (PIME) has been developed for monitoring trace level halogenated organic contaminants in ground water. A membrane extraction approach has been used, …


Supercritical Fluid Extraction (Sfe) And High Performance Liquid Chromotography (Hplc) Analysis Of Polycyclic Aromatic Hydrocarbon (Pah) Contaminated Soil, Marie Renee Gargas Aug 1998

Supercritical Fluid Extraction (Sfe) And High Performance Liquid Chromotography (Hplc) Analysis Of Polycyclic Aromatic Hydrocarbon (Pah) Contaminated Soil, Marie Renee Gargas

Theses

Methods for the extraction and analysis of polycyclic aromatic hydrocarbons (PAHs) from contaminated soil were evaluated for use in a treatability study. Candidate procedures were selected from EPA SW-846 (Third Edition) methods. Soxhlet extraction (3540B) was selected to determine initial PAH concentrations. Supercritical fluid extraction with carbon dioxide (SFE: 3561) and high performance liquid chromatography (HPLC: 8310) were evaluated for use as the extraction and analysis methods. Experimental soil was obtained from a petroleum product refinery site; a Certified Reference Material (CRM) was also studied.

Experiments focused on determining concentrations of anthracene, chrysene, fluoranthene, phenanthrene, and pyrene in untreated experimental …


The Feasibility Of Transferring Clean Technology From The United States To China : A Case Study From The Paper Industry, He Ning Aug 1998

The Feasibility Of Transferring Clean Technology From The United States To China : A Case Study From The Paper Industry, He Ning

Theses

In their pursuit of economic development, many developing countries are causing pollution at an alarming rate. One solution to the problem is the use of clean technology. Some developed countries have created various manufacture technologies which result in pollution prevention. There is a need for the transfer of clean technology from the developed countries to developing countries. It is beneficial to study the feasibility of such transfer.

The manufacturing processes of the paper industry are selected for this study. An investigation and comparison was conducted in order to evaluate the feasibility of clean technology transfer from the United States to …


Prospects Of Electrochemistry, Katsumi Niki Aug 1998

Prospects Of Electrochemistry, Katsumi Niki

Journal of Electrochemistry

No abstract provided.


Direct Electrochemical Reaction Of Cytochrome C At The Poly (Ethylene Oxide) Film Modified Gold Electrodes, Xiao-Gang Qu, Gong-Quan Sun, Hui Yang, Tian-Hong Lu Aug 1998

Direct Electrochemical Reaction Of Cytochrome C At The Poly (Ethylene Oxide) Film Modified Gold Electrodes, Xiao-Gang Qu, Gong-Quan Sun, Hui Yang, Tian-Hong Lu

Journal of Electrochemistry

In this paper, the direct electrochemical reaction of cytochrome c was sudied at the poly (ethylene oxide) film modified gold electrodes. It was found the PEO is a good promoter for the electrochemical reaction of cytochrome c, and the reversibility of reaction of cytochrome c was found to depend on the molecular weight of PEO and the morphology of the PEO films.


Ac Impedance Study Of The La0.8Sr0.2Mno3/Ysz Electrode, Shi-Zhong Wang, Yi Jiang, Ya-Hong Zhang, Jing-Wang Yan, Wen-Zhao Li Aug 1998

Ac Impedance Study Of The La0.8Sr0.2Mno3/Ysz Electrode, Shi-Zhong Wang, Yi Jiang, Ya-Hong Zhang, Jing-Wang Yan, Wen-Zhao Li

Journal of Electrochemistry

Electrochemical reaction of oxygen on the La0.8Sr0.2MnO3/YSZ electrode has been investigated in detail with AC impedance. The results demonstrated that the rate determining step(rds) of the reaction varies with the temperature, oxygen partial pressure and overpotential applied. At open circuit potential, the rds is the dissociative adsorption of oxygen on the LSM surface. A large number of electron holes are generated at high anodic overpotentials, while oxygen vacancies are formed at high cathodic overpotentials. The formation of the electron holes results in the electronic conduction of the YSZ electrolyte and the extension of the …


The Hydrogen Evolution Reaction On The Hydrogen Storage Alloy Electrode, Shi-Gang Lu, Qun Li, Qing-Guo Liu, Chun Lu, Bing Dang, Han-Xi Yang Aug 1998

The Hydrogen Evolution Reaction On The Hydrogen Storage Alloy Electrode, Shi-Gang Lu, Qun Li, Qing-Guo Liu, Chun Lu, Bing Dang, Han-Xi Yang

Journal of Electrochemistry

The hydrogen evolution reaction was studied in 1 mol/L KOH solution on the hydrogen storage alloy Mm(NiCoMnAl)5 electrode using open circuit potential decay and ac impedance technique. The reaction was found to proceed by the Volmer(discharge)-Tafel(recombination)mechanism. The measured overpotential η can be subdivided into two components η 1 and η 2 corresponding to the elementary Volmer and Tafel reaction. The Faradaic impedance was analyzed and characterized by the Volmer reaction. Then the exchange current density was evaluated . It was founded that the activity of hydrogen storage alloy electrode for the hydrogen evolution reaction was similar to that of …


Study Of Electrocrystallized N(N≥40) Multilayers In Boric Acid Solution, Ren-He Yin, Wen-Guang Shi, Wei-Min Cao Aug 1998

Study Of Electrocrystallized N(N≥40) Multilayers In Boric Acid Solution, Ren-He Yin, Wen-Guang Shi, Wei-Min Cao

Journal of Electrochemistry

Co(0.5 nm~2.2 nm)/Pt(2.0 nm)] n(n>40) multilayers were prepared by electrocrystallization on copper and glass carbon with a dual cell technique under potential control.The periodical modulated structure of the multilayers was demonstrated by the low angle X-ray diffraction. Potential shift negative to the deposition potential of the Co layer and positive to the deposition potential of the Pt layer decreased the value of the full width at half maximum(FWHM) of first Bragg Peak.CoPt 3 alloy was found as the interface of the multilayers by the middle angle X-ray diffraction.The hysteresis loops show that the easy magnetization of these multilayers lay …


Modification Of Carbon Anode Materials Of Lithium-Ion Secondary Battery, Yuping Wu, Chun-Rong Wan, Chang-Yin Jiang, Jiang-Iun Li Aug 1998

Modification Of Carbon Anode Materials Of Lithium-Ion Secondary Battery, Yuping Wu, Chun-Rong Wan, Chang-Yin Jiang, Jiang-Iun Li

Journal of Electrochemistry

In this paper, the latest research work on modification of carbon anode materials of lithium ion secondary battery is reviewed. Modification methods include: incorporation of nonmetal elements such as boron, silicon, nitrogen, phosphorus and sulfur, metal elements such as potassium, aluminum, gallium and transitional metal elements such as vanadium, nickel, cobalt, copper and iron and surface treatment such as oxidation and formation of surface layer. Since these methods can affect the carbon materials' electronics state, crystal structure and surface structure, the electrochemical properties of the carbon materials could probably be improved. Besides, mechanisms for lithium storage in carbonaceous materials are …


Influence Of Electrolytes To The Interfacial Electroc Characteristics Of The Porous Membrane Of Anodized Aluminum, Ya-Fe Kuang, Ling Wang, Mei-Yuan Wang Aug 1998

Influence Of Electrolytes To The Interfacial Electroc Characteristics Of The Porous Membrane Of Anodized Aluminum, Ya-Fe Kuang, Ling Wang, Mei-Yuan Wang

Journal of Electrochemistry

The influence of electrolytic composition on the interfacial electric Characteristic of the porous membrane membrance of anodized aluminum was investigated with a electrodialytic method. Results indicated that, when the porous membrane was pretreated with F -, PO 3- 4,SiO 2- 3 and tannic acid, the isoelectric point in 0.01 mol/L KCI, were shifted from normal 9.20 to 3.40, 4.30, 3.30 and 4.50, respectively, and responsive characteristics of ζ potential to pH was changed. Furthermore, after pretreatment of porous membrance with fuchsine basic and fuchsine acid solution,there was no isoelectric point at 2.0


Formation And Effect Of Tribo Cell For Fe Cr Alloy, Dong-Bai Sun, Tao Li, Hong-Ying Yu, De-Ji Yang Aug 1998

Formation And Effect Of Tribo Cell For Fe Cr Alloy, Dong-Bai Sun, Tao Li, Hong-Ying Yu, De-Ji Yang

Journal of Electrochemistry

The micro galvanic corrosion of 1Cr18 alloy and its effects on the triboelectrochemical behavior were investigated and analyzed in this article. It is shown that the micro galvanic corroson is due to the electrochemical inhomogenity on the surface of the alloy during the friction process. Like galvanic corrosion,the micro galvanic corrosion behaviors are greatly affected by the area ratio of unrubbed to rubbed surface.The load effects on electrochemical behavior of 1Cr18 alloy are also attributed to existence of electrochemical inhomogenity on the surface of materal.


Lithiun Insertion In Carbon Nanotubes, Guo-Tao Wu, Chun-Sheng Wang, Zhong-Fu Qi, Wenz-Hu Li Aug 1998

Lithiun Insertion In Carbon Nanotubes, Guo-Tao Wu, Chun-Sheng Wang, Zhong-Fu Qi, Wenz-Hu Li

Journal of Electrochemistry

Carbon nanotubes were produced by chemical vapour deposition(CVD) of acetylene under hydrogen gas.The reversible specific capacity of carbon nanotubes is up to 700 mAh/g, much higher than the theoretical specific capacity of graphite(372 mAh/g).After twenty charge/discharge cycles,the discharge capacity of carbon nanotube anode still maintains 65.3% of its original discharge capacity . Besides, the charge/discharge efficiency of carbon nanotube in the first charge/discharge cycle was found to improve from 42.6% up to 55.9% by coating carbon nanotubes with copper.


External Transducing Measurement Of The Internal Pressure In Sealed Battery By Resistance Strain Gauge, Han-Xi Yang, Rong-Hui Hu, Xin-Ping Ai, Cong-Zhi Yang, Sheng-Xian Li Aug 1998

External Transducing Measurement Of The Internal Pressure In Sealed Battery By Resistance Strain Gauge, Han-Xi Yang, Rong-Hui Hu, Xin-Ping Ai, Cong-Zhi Yang, Sheng-Xian Li

Journal of Electrochemistry

A novel method to monitor dynamically the internal pressure of sealed battery with no damage of the battery by using of resistance strain measurement technique is presented. This technique employs the resistence strain gauges in touch of the battery case and to detect the minimal change in the battery deformation due to the increasing internal pressure, electrode expantion or intrenal temperature rise. Application of the technique for the study of the effects of the battery processing factors on the battery performance is described taking Ni MH battery as example.


Photoelectrochemical Studies On Nanoporous Tio2/Pan Film Electrode, Min-Sheng Liu, Yan-Zhong Hao, Xue-Bin Qiao, Mai-Zhi Yang, Sheng-Min Cai Aug 1998

Photoelectrochemical Studies On Nanoporous Tio2/Pan Film Electrode, Min-Sheng Liu, Yan-Zhong Hao, Xue-Bin Qiao, Mai-Zhi Yang, Sheng-Min Cai

Journal of Electrochemistry

The photon to electricity conversion process of nanoporous TiO2/PAn film electrode was studied in electrolytes with and without redox couple by using the photocurrent action spectra and potential dependence of photocurrent. It is concluded that the nanoporous TiO2/PAn film electrode has a structure of duplex n type semiconductor layers. The band gap of PAn film is 2.88eV.The TiO2 nanoporous film electrode modified by PAn can extend the range of optical absorption into visible and infrared region and effectively increase the photocurrent in the visible and infrared region. The photocurrent threshold shifts to>600nm and conversion …


Studies On The Electrode Kinetics Of Electrooxidation Of Mn2+, Wan-Li Hu, Tong Su, Wei Guo, Ding Zhou Aug 1998

Studies On The Electrode Kinetics Of Electrooxidation Of Mn2+, Wan-Li Hu, Tong Su, Wei Guo, Ding Zhou

Journal of Electrochemistry

The mechanism of electrooxidation of MnSO4 on Pb Sb As alloy anode was investigated by using rotating disc electrode technique. The results shown that the conditional standard potential of Mn(Ⅲ)/Mn(Ⅱ)in 40% H2SO4 is 0.886 4 V.The rate controlling step of electrode process is mixed controlled by charge transfer and diffusion.


Electrochemical Behavior Of Chemically Prepared Ring-Substituted Polyanilines, Li-Zong Dai, Hui-Huang Wu Aug 1998

Electrochemical Behavior Of Chemically Prepared Ring-Substituted Polyanilines, Li-Zong Dai, Hui-Huang Wu

Journal of Electrochemistry

Polyaniline (PAn) has been known as a promising conducting polymer for technological applications. In research work elecrochemically synthesized PAn has been frequently used since electropolymerization is convenient to prepare the polymer film with controllable thickness or dopingon electrodes. However , the processibility of elecrosynthesized PAn is too poor to produce largearea devices because of its insolubility and infusibility. Recently, therefore, chemical polymerization has attracted a considerable attentionfl-3],  especially suitably derivatized ring substituted (e.g. alkyl or alkoxy) polyanilines have been synthesized, and their appreciable solubility in commonorganic solvents enable the preparation of film on industrial scale by casting. Moreover, emulsionpolymerization reduces …


Electrochemical Determination Of Trace Amouns Of Gold(Ⅲ)By Cathodic Sptripping Voltammetry Using A Carborn Paste Electroele Modified With Bacteria, Rong-Zong Hu, Hao Xu, Jin-Kun Fu, Wen-Yun Hu, Yan-Zhen Chen Aug 1998

Electrochemical Determination Of Trace Amouns Of Gold(Ⅲ)By Cathodic Sptripping Voltammetry Using A Carborn Paste Electroele Modified With Bacteria, Rong-Zong Hu, Hao Xu, Jin-Kun Fu, Wen-Yun Hu, Yan-Zhen Chen

Journal of Electrochemistry

An electrochemically pretreated carbon paste electrode modified with bacteria has been studied and used for determination of trace amounts of gold(Ⅲ). A detection limit of 1 ng/mL was obtained by applying cathodic stripping valtammetry. There is a linear relationship between the concentration and peak height in the range of 10~100 μg/mL. The ralative standard deviation of the response to 84.7 μg/mL Au(Ⅲ) is 3.43%.


Li-Ion Intercalation Charactersitic Of Gas-Coke, Zheng-Hua Deng, Xiao-Zheng Zhang, Xiao-Bing Ding, Mian-Zhong Chen, Wei-Guo Xie, Guo-Xiang Wan Aug 1998

Li-Ion Intercalation Charactersitic Of Gas-Coke, Zheng-Hua Deng, Xiao-Zheng Zhang, Xiao-Bing Ding, Mian-Zhong Chen, Wei-Guo Xie, Guo-Xiang Wan

Journal of Electrochemistry

A novel of carbon gas coke prepared from natural gas by thermoplasma technology has been studied. The cyclic voltametry and charge discharge test for the Li/gas coke cell demonstrated that this gas coke material has a good performance of the Li ion intercalation characteristic. X-ray diffraction pattern of the gas cokeis showed that the structure of gas coke is similar to the graphite and collapsed from order to disorder during the charge discharge cycles. The gas coke electrode give rise to a new diffraction peak at a low angle after intercalating Li ion and a reversible capacity with 235 mAh/g …