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University of South Carolina

1997

Articles 1 - 21 of 21

Full-Text Articles in Engineering

A Novel Laboratory Course On Advanced Chemical Engineering Experiments, Jochen A. Lauterbach, S. White, X. Lui, G. M. Bodner, W. N. Delgass Oct 1997

A Novel Laboratory Course On Advanced Chemical Engineering Experiments, Jochen A. Lauterbach, S. White, X. Lui, G. M. Bodner, W. N. Delgass

Faculty Publications

The chemical engineering curriculum in the United States has trained generations of technical experts who have successfully optimized chemical processes and products once they entered the chemical industry. The U.S. chemical industry, however, has entered a critical stage in which it must be able to create new and differentiated value through technical innovations that arc essential for long-term survival. This innovation process will require new skills that go far beyond the traditional expertise for the optimization of tasks possessed by young chemical engineers. The innovators must be able to identify new opportunities, explore the boundaries of technology, evaluate critical issues, …

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Electrode Performance Test On Single Ceramic Fuel Cells Using As Electrolyte Sr‐ And Mg‐Doped Lagao3, Kevin Huang, Man Feng, John B. Goodenough, Christopher Milliken Oct 1997

Electrode Performance Test On Single Ceramic Fuel Cells Using As Electrolyte Sr‐ And Mg‐Doped Lagao3, Kevin Huang, Man Feng, John B. Goodenough, Christopher Milliken

Faculty Publications

The electrode performance of a single solid oxide fuel cell was evaluated using a 500 μm thick La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) as the electrolyte membrane. Comparison of La0.6Sr0.4CoO3-δ (LSCo) and La0.9Sr0.1MnO3 (LSM) as cathodes showed LSCo gave an exchange current density two orders of magnitude higher than that of LSM. Comparison of CeO2/Ni and LSGM/Ni as anodes showed a degradation of the latter with time, and studies of the anode‐electrolyte interface and the reactivity of NiO and LSGM suggest better anode …

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An Ontology Tool For Distributed Information Environments, Kuhanandha Mahalingam, Michael N. Huhns Jun 1997

An Ontology Tool For Distributed Information Environments, Kuhanandha Mahalingam, Michael N. Huhns

Faculty Publications

This paper describes how ontologies can be used for query formulation and semantic reconciliation in large distributed information environments. It presents a tool, written in Java, that can be used to create and browse ontologies, and construct ontology-based queries. The tool incorporates several abstraction mechanisms that enable users to manage large ontologies, which are typical of large information environments. The tool is being applied to an information system for healthcare administrators, which spans hospitals, clinics, and governmental health departments.

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Internet-Based Agents: Applications And Infrastructure, Munindar P. Singh, Michael N. Huhns Jan 1997

Internet-Based Agents: Applications And Infrastructure, Munindar P. Singh, Michael N. Huhns

Faculty Publications

Software agents are mitigating the complexity of modern information systems—technically by providing a locus for managing information subsets, and psychologically by providing an abstraction for human interaction with them.

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The Effects Of Organic Compounds On Inhibition Of Hydrogen Permeation Through A Mild Steel Membrane, H. A. Duarte, D. M. See, Branko N. Popov, Ralph E. White Jan 1997

The Effects Of Organic Compounds On Inhibition Of Hydrogen Permeation Through A Mild Steel Membrane, H. A. Duarte, D. M. See, Branko N. Popov, Ralph E. White

Faculty Publications

The effectiveness of 5-(4-pyridyl)-2,7-nonadiene, and 1 phenyl-2-propyn-ol (PP) on inhibition of the hydrogen evolution reaction on a 1010 steel membrane and on the degree of hydrogen ingress into the membrane was determined. Hydrogen evolution rates and permeation currents were monitored as a function of time at different applied potentials. In the presence of 0.5 g/liter PP in the electrolyte, the hydrogen discharge and permeation current density were inhibited by 98 and 95%, respectively.

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Molecular-Level Modeling Of The Viscoelasticity Of Crosslinked Polymers: Effect Of Time And Temperature, Philip P. Simon, Harry J. Ploehn Jan 1997

Molecular-Level Modeling Of The Viscoelasticity Of Crosslinked Polymers: Effect Of Time And Temperature, Philip P. Simon, Harry J. Ploehn

Faculty Publications

We present a new molecular-level picture of chain dynamics for describing the viscoelasticity of crosslinked polymers. The associated mathematical model consists of a time-dependent momentum balance on a representative polymer segment in the crosslinked network, plus phenomenological expressions for forces acting on the segments. These include a cohesive force that accounts for intermolecular attraction, an entropic force describing the thermodynamics governing chain conformations, and a frictional force that captures the temperature dependence of relative chain motion. We treat the case of oscillatory uniaxial deformation. Solution of the model equations in the frequency domain yields the dynamic moduli as functions of …

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Mathematical Modeling Of Proton‐Exchange‐Membrane Fuel‐Cell Stacks, Dhanwa Thirumalai, Ralph E. White Jan 1997

Mathematical Modeling Of Proton‐Exchange‐Membrane Fuel‐Cell Stacks, Dhanwa Thirumalai, Ralph E. White

Faculty Publications

No abstract provided.

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The Effects Of Organic Compounds On Inhibition Of Hydrogen Permeation Through A Mild Steel Membrane, H. A. Duarte, D. M. See, Branko Popov, Ralph E. White Jan 1997

The Effects Of Organic Compounds On Inhibition Of Hydrogen Permeation Through A Mild Steel Membrane, H. A. Duarte, D. M. See, Branko Popov, Ralph E. White

Faculty Publications

No abstract provided.

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Chemical Stability Study Of Bace0.9Nd0.1O3−Α High Temperature Proton-Conducting Ceramic, Fanglin Chen, O. Toft Sorensen, Guangyao Meng, Dingkum Peng Jan 1997

Chemical Stability Study Of Bace0.9Nd0.1O3−Α High Temperature Proton-Conducting Ceramic, Fanglin Chen, O. Toft Sorensen, Guangyao Meng, Dingkum Peng

Faculty Publications

BaCe0.9Nd0.1O3−a (BCN) ceramic is known to be an excellent high-temperature proton conductor and is a candidate electrolyte for use in solid oxide fuel cells, hydrogen or steam sensors and steam electrolysers. In this work, the chemical stability of BCN was investigated systematically by combining XRD and DTA–TG techniques to study its processing compatibility and its feasibility in potential applications. It was found that above 1200 °C, BCN reacted with alumina or zirconia, leading to the loss of barium and an excess of cerium. In cold water, both sintered BCN disks and powder samples had very …

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Preparation Of Nd-Doped Baceo3 Proton-Conducting Ceramics By Homogeneous Oxalate Coprecipitation, Fanglin Chen, Ping Wang, O. Toft Sorensen, Guangyao Meng, Dingkum Peng Jan 1997

Preparation Of Nd-Doped Baceo3 Proton-Conducting Ceramics By Homogeneous Oxalate Coprecipitation, Fanglin Chen, Ping Wang, O. Toft Sorensen, Guangyao Meng, Dingkum Peng

Faculty Publications

Nd-doped BaCeO3 have been obtained from homogeneous coprecipitated oxalates when calcined at temperatures T≥1000 °C. Ball-milling of the calcined powders well disperses the agglomerates and consequently has a beneficial effect in the densification process. The calcination temperature has a major influence on the sintering process and powders calcined at 1100 °C possess good sinterabilities. The pressure applied to press the green pellets has no apparent influence on the sintered density at sintering temperatures of T≥1400 °C. By controlling the processing variables it was possible to obtain near fully dense Nd-doped BaCeO3 ceramics with homogeneous microstructure at a sintering …

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Molecular-Level Modeling Of The Viscoelasticity Of Crosslinked Polymers: Effect Of Time And Temperature, P. P. Simon, Harry J. Ploehn Jan 1997

Molecular-Level Modeling Of The Viscoelasticity Of Crosslinked Polymers: Effect Of Time And Temperature, P. P. Simon, Harry J. Ploehn

Faculty Publications

We present a new molecular-level picture of chain dynamics for describing the viscoelasticity of crosslinked polymers. The associated mathematical model consists of a time-dependent momentum balance on a representative polymer segment in the crosslinked network, plus phenomenological expressions for forces acting on the segments. These include a cohesive force that accounts for intermolecular attraction, an entropic force describing the thermodynamics governing chain conformations, and a frictional force that captures the temperature dependence of relative chain motion. We treat the case of oscillatory uniaxial deformation. Solution of the model equations in the frequency domain yields the dynamic moduli as functions of …

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Ontologies For Agents, Michael N. Huhns, Munindar P. Singh Jan 1997

Ontologies For Agents, Michael N. Huhns, Munindar P. Singh

Faculty Publications

An ontology is a computational model of some portion of the world. It is often captured in some form of a semantic network-a graph whose nodes are concepts or individual objects and whose arcs represent relationships or associations among the concepts. This network is augmented by properties and attributes, constraints, functions, and rules that govern the behavior of the concepts. Formally, an ontology is an agreement about a shared conceptualization, which includes frameworks for modeling domain knowledge and agreements about the representation of particular domain theories. Definitions associate the names of entities in a universe of discourse (for example, classes, …

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The Agent Test, Michael N. Huhns, Munindar P. Singh Jan 1997

The Agent Test, Michael N. Huhns, Munindar P. Singh

Faculty Publications

The authors consider agents on the World Wide Web, including information retrieval agents. They propose a test for agenthood, involving communication in multi-agent systems.

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Mobile Agents, Michael N. Huhns, Munindar P. Singh Jan 1997

Mobile Agents, Michael N. Huhns, Munindar P. Singh

Faculty Publications

A lot of agents are executing on the Web, and some of them are starting to move around. While most agents are static (existing as a single process or thread on one host), others can pick up and move their code and data to a new host where they resume executing.

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Conversational Agents, Michael N. Huhns, Munindar P. Singh Jan 1997

Conversational Agents, Michael N. Huhns, Munindar P. Singh

Faculty Publications

When you build or buy an agent for the Web, you want it to perform as well as possible. Increasingly, this means your agent should take advantage not only of the Web's information resources, but also of all the other agents that might be operating there.

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Agents Are Everywhere!, Michael N. Huhns, Munindar P. Singh Jan 1997

Agents Are Everywhere!, Michael N. Huhns, Munindar P. Singh

Faculty Publications

A decade ago this claim would have evoked images from the Cold War—and probably gotten this column classified! Today, it describes one of the hottest technical areas on the Internet.

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Hierarchical Classification As An Aid To Browsing, John R. Rose, Caroline M. Eastman Jan 1997

Hierarchical Classification As An Aid To Browsing, John R. Rose, Caroline M. Eastman

Faculty Publications

An approach to browsing large chemical reaction databases is presented. The method that is described builds on earlier work in which unsupervised hierarchical classification was used to extract generalizations of reaction classes from reaction databases for use in reaction knowledge bases. The method described in this paper involves classification based on both semantic and topological features. It supports the creation of deep hierarchies in which succeeding levels represent increasing degrees of abstraction. The creation of a hierarchy allows the user to quickly locate interesting items or classes of items by performing a tree traversal as opposed to sequentially scanning a …

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Electrowinning Of Nonnoble Metals With Simultaneous Hydrogen Evolution At Flow-Through Porous Electrodes Iii. Time Effects, Mahmoud M. Saleh, John W Weidner, Bahgat E. El-Anadouli, Badr G. Ateya Jan 1997

Electrowinning Of Nonnoble Metals With Simultaneous Hydrogen Evolution At Flow-Through Porous Electrodes Iii. Time Effects, Mahmoud M. Saleh, John W Weidner, Bahgat E. El-Anadouli, Badr G. Ateya

Faculty Publications

The electrowinning of zinc from a recirculating alkaline zincate solution at a flow-through porous electrode was investigated. Experimental results were obtained to test the predictions of a mathematical model. The effects of electrolyte flow rate, cell current, and electrode thickness on the concentration-time relations and coulombic efficiency-time relations were studied. The experimental results show that the highest recovery rate was obtained at both high flow rates and cell currents. There is, however, a practical limit for increasing both the cell current and the electrolyte flow rate. Reasonable agreement between the model predictions and experimental results was obtained. A case study …

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An Electrochemical Route For Making Porous Nickel Oxide Electrochemical Capacitors, Venkat Srinivasan, John W. Weidner Jan 1997

An Electrochemical Route For Making Porous Nickel Oxide Electrochemical Capacitors, Venkat Srinivasan, John W. Weidner

Faculty Publications

Porous nickel oxide films were prepared by electrochemically precipitating nickel hydroxide and heating the hydroxide in air at 300°C. The resulting nickel oxide films behave as an electrochemical capacitor with a specific capacitance of 59 F/g electrode material. These nickel oxide films maintain high utilization at high rates of discharge (i.e., high power density) and have excellent cycle life. Porous cobalt oxide films were also synthesized. Although the specific capacitances of these films are approximately one-fifth that of the nickel oxide films, the results demonstrate the versatility of fabricating a wide range of porous metal oxide films using …

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Ellipsometric And Raman Spectroscopic Study Of Thermally Formed Films On Titanium, E. Hristova, Lj. Arsov, Branko N. Popov, Ralph E. White Jan 1997

Ellipsometric And Raman Spectroscopic Study Of Thermally Formed Films On Titanium, E. Hristova, Lj. Arsov, Branko N. Popov, Ralph E. White

Faculty Publications

Thermal films on titanium surfaces were formed by heating titanium samples in air at atmospheric pressure. The optical constants, thickness, and structure of the formed films at various temperatures and times of heating were investigated by ellipsometry and Raman spectroscopy. The complex index of refraction and the thickness of generated films were determined by comparing the experimental loci and obtained by ellipsometric measurements with theoretical computed vs. curves. It was found that the thickness in homogeneity and porosity of formed films increase with increasing temperature and the duration of the thermal treatment. Beyond a certain critical temperature, the appearance of …

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Governing Equations For Transport In Porous Electrodes, Pauline De Vidts, Ralph E. White Jan 1997

Governing Equations For Transport In Porous Electrodes, Pauline De Vidts, Ralph E. White

Faculty Publications

No abstract provided.

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