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Articles 1 - 16 of 16
Full-Text Articles in Engineering
Percolation Paths Of Three-Dimensions In Sensitized Stainless Steel, Alisa J. Millar Henrie
Percolation Paths Of Three-Dimensions In Sensitized Stainless Steel, Alisa J. Millar Henrie
Faculty Publications
The study of three-dimensional percolation paths through materials is important in its contribution to understanding defect sensitive properties of materials. This work shows the importance of grain boundary character in modeling defect sensitive boundaries. Also presented are trends of percolation of sensitized grain boundaries in 304 stainless steel (304SS). Of particular interest is how open paths form in a three-dimensional model created through serial sectioning. Evidence is presented that triple or quadruple points that contain typically two boundaries with special character that intersect the percolation path break up the path. Some boundaries with no known special qualities; they are not …
Mobile Agent Based Distributed Network Management : Modeling, Methodologies And Applications, Jian Ye
Mobile Agent Based Distributed Network Management : Modeling, Methodologies And Applications, Jian Ye
Dissertations
The explosive growth of the Internet and the continued dramatic increase for all wireless services are fueling the demand for increased capacity, data rates, support of multimedia services, and support for different Quality of Services (QoS) requirements for different classes of services. Furthermore future communication networks will be strongly characterized by heterogeneity. In order to meet the objectives of instant adaptability to the users' requirements and of interoperability and seamless operation within the heterogeneous networking environments, flexibility in terms of network and resource management will be a key design issue. The new emerging technology of mobile agent (MA) has arisen …
Electromagnetic Interference (Emi) Of System-On-Package (Sop), Toshio Sudo, Hideki Sasaki, Norio Masuda, James L. Drewniak
Electromagnetic Interference (Emi) Of System-On-Package (Sop), Toshio Sudo, Hideki Sasaki, Norio Masuda, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
Electromagnetic interference (EMI) issues are expected to be crucial for next-generation system-on-package (SOP) integrated high-performance digital LSIs and for radio frequency (RF) and analog circuits. Ordinarily in SOPs, high-performance digital LSIs are sources of EMI, while RF and analog circuits are affected by EMI (victims). This paper describes the following aspects of EMI in SOPs: 1) die/package-level EMI; 2) substrate-level EMI; 3) electromagnetic modeling and simulation; and 4) near electromagnetic field measurement. First, LSI designs are discussed with regard to radiated emission. The signal-return path loop and switching current in the power/ground line are inherent sources of EMI. The EMI …
Numerical Modeling Of Friction Stir Welding: A Comparison Of Alegra And Forge3, Alma H. Oliphant
Numerical Modeling Of Friction Stir Welding: A Comparison Of Alegra And Forge3, Alma H. Oliphant
Theses and Dissertations
The objective of this research was to evaluate the capabilities of ALEGRA, a Sandia National Labs hydrocode, and Forge3, a Transvalor S.A. product, to accurately model the Friction Stir Welding Process. ALEGRA and Forge3 are discussed in light of the inherent challenges of modeling Friction Stir Welding, and a rotational boundary condition is added to ALEGRA. Results are presented from Friction Stir Welding modeling outputs from both ALEGRA and Forge3. ALEGRA is shown to be incapable of modeling the Friction Stir Welding process, in large part due to its focus on shock propagation, which causes extremely small time steps. Forge3 …
Astronaut Eva Exposure Estimates From Cad Model Spacesuit Geometry, Giovanni De Angelis, Brooke M. Anderson, William Atwell, John E. Nealy, Gary D. Qualls, John W. Wilson
Astronaut Eva Exposure Estimates From Cad Model Spacesuit Geometry, Giovanni De Angelis, Brooke M. Anderson, William Atwell, John E. Nealy, Gary D. Qualls, John W. Wilson
Mathematics & Statistics Faculty Publications
Ongoing assembly and maintenance activities at the International Space Station (ISS) require much more extravehicular activity (EVA) than did the earlier U.S. Space Shuttle missions. It is thus desirable to determine and analyze, and possibly foresee, as accurately as possible what radiation exposures crew members involved in EVAs will experience in order to minimize risks and to establish exposure limits that must not to be exceeded. A detailed CAD model of the U.S. Space Shuttle EVA Spacesuit, developed at NASA Langley Research Center (LaRC), is used to represent the directional shielding of an astronaut; it has detailed helmet and backpack …
Implications Of On-Ground Nitrogen Loading And Soil Transformations On Ground Water Quality Management, M. Almasri, Jagath J. Kaluarachchi
Implications Of On-Ground Nitrogen Loading And Soil Transformations On Ground Water Quality Management, M. Almasri, Jagath J. Kaluarachchi
Civil and Environmental Engineering Faculty Publications
This paper presents a modeling approach based on a geographic information system (GIS) to estimate the variability of on-ground nitrogen loading and the corresponding nitrate leaching to ground water. The methodology integrates all point and nonpoint sources of nitrogen, the national land cover database, soil nitrogen transformations, and the uncertainty of key soil and land use-related parameters to predict the nitrate mass leaching to ground water. The analysis considered 21 different land use classes with information derived from nitrogen sources such as fertilizer and dairy manure applications, dairy lagoons, septic systems, and dry and wet depositions. Simulations were performed at …
The Use Of A Water Quality Model To Evaluate The Impacts Of Combined Sewer Overflows On The Lower Hudson River, Wen-Pin Shu
The Use Of A Water Quality Model To Evaluate The Impacts Of Combined Sewer Overflows On The Lower Hudson River, Wen-Pin Shu
Dissertations
CSO discharges have long been recognized as a significant source of water pollution. While many sources of water pollution have been controlled over the past 20 years, CSOs continue to be a main environmental concern in several areas, especially in old cities. In the past, most CSO research focused on the CSO control processes, including floatables and suspended solids removal. Few studies have been conducted in the area of the impacts of CSO discharge on the receiving water quality. To achieve this purpose, a powerful water-modeling tool, WASP 6.1, is utilized in this study. The Lower Hudson River is selected …
Finite Element Modeling Of Contact Interface Between Trans-Tibial Residual Limb And Prosthetic Socket, Winson Lee, Ming Zhang, Xiaohong Jia, Jason Cheung
Finite Element Modeling Of Contact Interface Between Trans-Tibial Residual Limb And Prosthetic Socket, Winson Lee, Ming Zhang, Xiaohong Jia, Jason Cheung
Faculty of Engineering and Information Sciences - Papers: Part A
Finite element method has been identified as a useful tool to understand the load transfer mechanics between a residual limb and its prosthetic socket. This paper proposed a new practical approach in modeling the contact interface with consideration of the friction/slip conditions and pre-stresses applied on the limb within a rectified socket. The residual limb and socket were modeled as two separate structures and their interactions were simulated using automated contact methods. Some regions of the limb penetrated into the socket because of socket modification. In the first step of the simulation, the penetrated limb surface was moved onto the …
Numerical Modeling Of Flow At An Open-Channel Confluence, Muttucumaru Sivakumar, Kalyani Dissanayake, Ajit Godbole
Numerical Modeling Of Flow At An Open-Channel Confluence, Muttucumaru Sivakumar, Kalyani Dissanayake, Ajit Godbole
Faculty of Engineering - Papers (Archive)
This paper presents the first part of a 3D numerical simulation of a horizontal-bed open-channel water flow with a 90° equal-width junction. A commercially available CFD package is used. The results of the numerical simulations are compared with the experimental data published by previous researchers. The numerical simulation was carried out in two steps: (a) using a Cartesian mesh to determine the shape of the free surface, and (b) using a body-fitted mesh conforming to the free-surface shape. The first step yielded a fair comparison between simulated and experimentally determined free-surface profiles. Further work on the simulation in the second …
Analysis And Integration Of A Debris Model In The Virtual Range Projec, Luis Robledo
Analysis And Integration Of A Debris Model In The Virtual Range Projec, Luis Robledo
Electronic Theses and Dissertations
After the accident of the STS 107 Columbia Space Shuttle, great concern has been focused on the risk associated to the population on the ground. Before this accident happened, re-entry routes as well as risk calculation of were not of public concern. Two issues that have been raised from this lamentable accident relate to spacecraft security and to public safety. The integration of a debris model has been part of the original conceptual architecture of the Virtual Range Project. Its integration has been considered as a specific research due to the complexity of the models and the difficulties to obtain …
Modeling Of Contaminant Transport In On-Site Waste Disposal Systems, Thidarat Bunsri, Dharmappa Hagare, Muttucumaru Sivakumar
Modeling Of Contaminant Transport In On-Site Waste Disposal Systems, Thidarat Bunsri, Dharmappa Hagare, Muttucumaru Sivakumar
Faculty of Engineering - Papers (Archive)
One of the most common problems of septic systems is poor drainage in the field. Septic systems release number of organic contaminants that cause groundwater pollution, especially organic substances, nutrients and pathogenic microorganisms. However, there are mechanisms that operate between soil and contaminants, which can purify the septic tank effluent. Below the drainage field, soil is separated into two zones; unsaturated and saturated zone, which provide the water movement mainly in vertical and horizontal direction, respectively. The purpose of this paper is to develop a conceptual model and to define governing equations for the transport of septic tank effluent in …
Nitrification Investigation And Modeling In The Chloraminated Drinking Water Distribution System, Suibing Liu
Nitrification Investigation And Modeling In The Chloraminated Drinking Water Distribution System, Suibing Liu
Electronic Theses and Dissertations
This dissertation consists of five papers concerning nitrification in chloraminated drinking water distribution systems in a one and a half year field study. Seven finished waters were produced from different treatment processes and distributed to eighteen pilot distribution systems (PDSs) that were made pipes taken from actual distribution systems. Unlined cast iron (UCI), galvanized steel (G), lined cast iron (LCI), and PVC pipes were used to build the PDSs. All finished waters were stabilized and chloraminated before entering the PDSs. This dissertation consists of five major parts. (1) System variations of nitrates, nitrites, DO, pH, alkalinity, temperature, chloramine residuals and …
An Approach To Automating Data Collection For Simulation, Irin Portnaya
An Approach To Automating Data Collection For Simulation, Irin Portnaya
Electronic Theses and Dissertations
In past years many industries have utilized simulation as a means for decision making. That wave has introduced simulation as a powerful optimization and development tool in the manufacturing industry. Input data collection is a significant and complex event in the process of simulation. The simulation professionals have grown to accept it is as a strenuous but necessary task. Due to the nature of this task, data collection problems are numerous and vary depending on the situation. These problems may involve time consumption, lack of data, lack of structure, etc. This study concentrates on the challenges of input data collection …
Evaluation Of Surface (Top Down) Longitudinal Wheel Path Cracking, Terhi K. Pellinen, Geoff Rowe, Kalapi Biswas
Evaluation Of Surface (Top Down) Longitudinal Wheel Path Cracking, Terhi K. Pellinen, Geoff Rowe, Kalapi Biswas
JTRP Technical Reports
The research involved evaluating three surface cracked pavements during 2002 and 2003. A 500m section of I-65 North of Lafayette was chosen as the first site (designated as Site 1), an I-65 section in downtown Indianapolis was the second site (Site 2), and US-421 in Madison was the third site (Site 3). Site 1 had 11-year old pavement, Site 2 had 12-year old pavement and Site 3 had 4.5-year old pavement. All these sites exhibited longitudinal wheel path cracking which was later identified as top-down cracking. All sites had excellent structural capacity indicating that the top-down cracking was confined in …
Electrodeposition Of Feconicu Quaternary System, Qiang Huang
Electrodeposition Of Feconicu Quaternary System, Qiang Huang
LSU Doctoral Dissertations
Electrodeposition is a cost-effective method to produce thin film materials, which have been used widely in the microelectronic industry, and is advantageous to fabricate metal deposits into recessed and curved areas. In this dissertation, FeCoNiCu quaternary alloy system was investigated, both experimentally and theoretically, for fabrication of multilayers, grating structures, and nanowires. Multilayer structures are composed of alternating ferromagnetic and nonmagnetic nanometric layers, and are of interest due to the giant magnetoresistance (GMR) property it possesses, a change in electric resistance in the presence of an external magnetic field. In addition, the compositional modulation, or the composition contrast, in multilayer …
Optimization Modeling For Groundwater And Conjunctive Use Water Policy Development, Richard C. Peralta, R. Shulstad
Optimization Modeling For Groundwater And Conjunctive Use Water Policy Development, Richard C. Peralta, R. Shulstad
Civil and Environmental Engineering Faculty Publications
Planners must sometimes decide how to restrict or reduce groundwater use to prevent unacceptable future problems. Often there are several alternatives (policies). Comparing policies can involve formulating a sustained groundwater yield optimization problem and computing an optimal groundwater pumping strategy for each. This is easy via the SOMOS simulation/optimization (S/O) model. Subsequent analysis can include: flow simulation to predict transient water level response to pumping; and economic evaluation to estimate costs and returns. Two examples predict the best consequences of potential physical and legal management policies for alluvial and valley basin fill aquifers hydraulically linked to surface waters. Results show …