Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

2004

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 1051 - 1080 of 2785

Full-Text Articles in Engineering

Developing A Sensing System For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic, Bingmei Fu, Yingtao Jiang, Jian Ma Apr 2004

Developing A Sensing System For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic, Bingmei Fu, Yingtao Jiang, Jian Ma

Mechanical Engineering Faculty Research

Although liquid lead-bismuth eutectic (LBE) is a good candidate for the coolant in the subcritical transmutation blanket, it is known to be very corrosive to stainless steel, the material of the carrying tubes and the containers. Such a corrosion problem can be prevented by producing and maintaining a protective oxide layer on the exposed surface of stainless steel. The proper formation of this oxide layer critically depends on the accurate measurement and control of the oxygen concentration in the liquid LBE. YSZ (Yttria Stabilized Zirconia) oxygen sensors, using molten bismuth saturated with oxygen as the reference, have been utilized to …

Go to article

Robust Procedures For Obtaining Assembly Contact State Extremal Configurations, Pan Feng, Joseph M. Schimmels Apr 2004

Robust Procedures For Obtaining Assembly Contact State Extremal Configurations, Pan Feng, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

Two important components in the selection of an admittance that facilitates force-guided assembly are the identification of: 1) the set of feasible contact states, and 2) the set of configurations that span each contact state, i.e., the extremal configurations. We present a procedure to automatically generate both sets from CAD models of the assembly parts. In the procedure, all possible combinations of principle contacts are considered when generating hypothesized contact states. The feasibility of each is then evaluated in a genetic algorithm based optimization procedure. The maximum and minimum value of each of the 6 configuration variables spanning each contact …

Go to article

Detection Of Closed Hyperstreamlines, Thomas Wischgoll Apr 2004

Detection Of Closed Hyperstreamlines, Thomas Wischgoll

Computer Science and Engineering Faculty Publications

No abstract provided.

Go to article

Corrosion Research On Rock Bolts And Steel Sets For Sub-Surface Reinforcement Of The Yucca Mountain Repository, Dhanesh Chandra, Jaak J.K. Daemen, Amy J. Smiecinski Apr 2004

Corrosion Research On Rock Bolts And Steel Sets For Sub-Surface Reinforcement Of The Yucca Mountain Repository, Dhanesh Chandra, Jaak J.K. Daemen, Amy J. Smiecinski

Publications (YM)

Corrosion resistance of Yucca Mountain (YM) carbon steel rock bolt (0.44%C) and I-beam steel sets (0.08%C) towards electrochemical/general corrosion, stress corrosion cracking (SCC), and hydrogen embrittlement (HE) susceptibility has been determined using simulated YM waters in this Task 18 for YM site underground repository tunnel support. These findings show the corrosion behavior of these structural support members with and without applied stresses in simulated YM environments. The simulated YM waters were increased in nominal concentrations from Ix to lOOx (three different levels) for electrochemical and other corrosion studies. The effect of temperature, of significance to YM repository, on the corrosion …

Go to article

Molecular-Dynamics Simulation Of The Effect Of Ions On A Liquid–Liquid Interface For A Partially Miscible Mixture, Richard L. Rowley, Kent E. Wardle, Eric Carlson, Douglas Henderson Apr 2004

Molecular-Dynamics Simulation Of The Effect Of Ions On A Liquid–Liquid Interface For A Partially Miscible Mixture, Richard L. Rowley, Kent E. Wardle, Eric Carlson, Douglas Henderson

Faculty Publications

Molecular-dynamics simulations were performed to model the effect of added salt ions on the liquid-liquid interface in a partially miscible system. Simulations of the interface between saturated phases of a model 1-hexanol + water system show a bilayer structure of 1-hexanol molecules at the interface with OH heads of the first layer directed into the water phase and the opposite orientation for the second layer. The alignment of the polar OH groups at the interface stabilizes a charge separation of sodium and chloride ions when salt is introduced into the aqueous phase, producing an electrical double layer. Chloride ions aggregate …

Go to article

A Tutorial On Text-Independent Speaker Verification, Frédéric Bimbot, Jean-François Bonastre, Corinne Fredouille, Guillaume Gravier, Ivan Magrin-Chagnolleau, Sylvain Meignier, Teva Merlin, Javier Ortega-García, Dijana Petrovska-Delacrétaz, Douglas A. Reynolds Apr 2004

A Tutorial On Text-Independent Speaker Verification, Frédéric Bimbot, Jean-François Bonastre, Corinne Fredouille, Guillaume Gravier, Ivan Magrin-Chagnolleau, Sylvain Meignier, Teva Merlin, Javier Ortega-García, Dijana Petrovska-Delacrétaz, Douglas A. Reynolds

Presidential Fellows Articles and Research

This paper presents an overview of a state-of-the-art text-independent speaker verification system. First, an introduction proposes a modular scheme of the training and test phases of a speaker verification system. Then, the most commonly speech parameterization used in speaker verification, namely, cepstral analysis, is detailed. Gaussian mixture modeling, which is the speaker modeling technique used in most systems, is then explained. A few speaker modeling alternatives, namely, neural networks and support vector machines, are mentioned. Normalization of scores is then explained, as this is a very important step to deal with real-world data. The evaluation of a speaker verification system …

Go to article

Gradient-Based Non-Linear Microstructure Design, Brent L. Adams, M. Lyon Apr 2004

Gradient-Based Non-Linear Microstructure Design, Brent L. Adams, M. Lyon

Faculty Publications

The support of this research by the Army Research Office is gratefully acknowledged. M. Lyon is supported by a National Science Foundation Graduate Research Fellowship. Fourier analysis is implemented on the orientation distribution of a polycrystalline microstructure. The linearity and convexity of the Fourier space, with respect to orientation, allows one to consider all possible distributions by considering all linear combinations of single-grain orientations. The limits of the Fourier space are therefore defined by the solutions to a set of linear programming problems. A unique approach to the linear programming, similar to the Krylov subspace methods for obtaining solutions to …

Go to article

High Resolution Turbulence Treatment Of F/A-18 Tail Buffet, Scott A. Morton, Russell M. Cummings, Denis B. Kholodar Apr 2004

High Resolution Turbulence Treatment Of F/A-18 Tail Buffet, Scott A. Morton, Russell M. Cummings, Denis B. Kholodar

Aerospace Engineering

Unsteady tail loads of the F/A-18 are computed using various turbulence models at an angle of attack consistent with buffet induced by leading-edge extension vortex breakdown. Comparison of these industry standard turbulence models with the Detached Eddy Simulation (DES) hybrid RANS-LES approach reveals the inadequacies of RANS methods and the ability of DES to reproduce the observed unsteadiness at these conditions. Computed vortex breakdown position and frequencies of the DES method are shown to be accurate by comparison to flight test and experimental results. Finally, comparison of the DES unsteady tail pressures with flight-test tail pressures reveal the ability of …

Go to article

A Vector Quantization Method For Nearest Neighbor Classifier Design, Chen-Wen Yen, Chieh-Neng Young, Mark L. Nagurka Apr 2004

A Vector Quantization Method For Nearest Neighbor Classifier Design, Chen-Wen Yen, Chieh-Neng Young, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper proposes a nearest neighbor classifier design method based on vector quantization (VQ). By investigating the error distribution pattern of the training set, the VQ technique is applied to generate prototypes incrementally until the desired classification result is reached. Experimental results demonstrate the effectiveness of the method.

Go to article

Polarized Neutron Measurement Of Magnetic Order In Yba2⁢Cu3⁢O6.45, Herbert A. Mook, Pengcheng Dai, Stephen M. Hayden, Arno Hiess, Sh Lee, Fatih Dogan Apr 2004

Polarized Neutron Measurement Of Magnetic Order In Yba2⁢Cu3⁢O6.45, Herbert A. Mook, Pengcheng Dai, Stephen M. Hayden, Arno Hiess, Sh Lee, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Orbital current order of the d-density-wave type has been postulated to explain the pseudo gap in high temperature superconductors. We have performed neutron scattering experiments to search for this order and show here the results obtained on an YBa2⁢Cu3⁢O6.45 sample using the best neutron spectrometers available. We argue that the data are consistent with a small, largely c-axis-directed moment, found below about 200 K.

Go to article

Hazards Identification Model For Rail Rapid Transit Accidents, Lung-Chuang Wang Apr 2004

Hazards Identification Model For Rail Rapid Transit Accidents, Lung-Chuang Wang

Journal of Marine Science and Technology–Taiwan

In comparison with the other transportation modes, rail rapid transit already enjoys a higher degree of safety as it is designed with the exclusive right of way and the automatic train control and monitoring systems. Nevertheless, rail rapid transit systems are not free from serious accidents, which often led to human injuries and facility damages. The planning of accident prevention and emergency measures, therefore, are still important issues of the rail rapid transit operations. The model presented in this study analyses the process of hazard identification in two stages, which clearly indicate the factors of the inherent and direct hazard …

Go to article

2004 - The Ninth Annual Symposium Of Student Scholars Apr 2004

2004 - The Ninth Annual Symposium Of Student Scholars

Symposium of Student Scholars Program Books

The full program book from the Ninth Annual Symposium of Student Scholars, held on April 16, 2004. Includes abstracts from the presentations and posters.

Go to article

Coupled Problem Of Thermoelasticity For Multilayered Spheres With Time-Dependent Boundary Conditions, Zong-Yi Lee Apr 2004

Coupled Problem Of Thermoelasticity For Multilayered Spheres With Time-Dependent Boundary Conditions, Zong-Yi Lee

Journal of Marine Science and Technology–Taiwan

This paper deals with quasi-static coupled thermoelastic problems for multilayered spheres. Using the Laplace transform with respect to time, the general solutions of the governing equations are obtained in transform domain. The solution is obtained by using the matrix similarity transformation and inverse Laplace transform. We obtain solutions for the temperature and thermal deformation distributions for a transient state. It is demonstrated that the computational procedures established in this paper are capable of solving the generalized thermoelasticity problem of multilayered spheres.

Go to article

Highly Selective, Electrically Conductive Monolayer Of Nanoparticles On Live Bacteria, V Berry, Rangaswamy S, Ravi F. Saraf Apr 2004

Highly Selective, Electrically Conductive Monolayer Of Nanoparticles On Live Bacteria, V Berry, Rangaswamy S, Ravi F. Saraf

Papers in Nanotechnology

Using specific peptide−bacteria affinity, a monolayer of 30 nm Au particle is selectively deposited on live bacteria surface to produce electrically conducting bridges spanning over 12 μm. The conductivity of the monolayer network is further improved by over 10-fold by “electric-field annealing”. The annealing process is explained by a percolation model.

Go to article

Optimal Pitch, Speed And Fuel Control At Sea, Thomas Hellström Apr 2004

Optimal Pitch, Speed And Fuel Control At Sea, Thomas Hellström

Journal of Marine Science and Technology–Taiwan

This paper discusses algorithms for fuel saving control for large vessels. The fuel saving is achieved by optimizing control at three levels: low level propeller and main engine control, dynamic speed control to avoid peeks in the fuel consumption and finally route planning for optimal speed profiles compensated for varying depth and weather conditions. The control problems involve classical control functions as well as numerical optimization.

Go to article

Numerical Optimization Of Sound Absorption Systems With Constrained Single-Layer Absorber, Ying-Chun Chang, Long-Jyi Yeh, Min-Chie Chiu, Gaung-Jer Lai Apr 2004

Numerical Optimization Of Sound Absorption Systems With Constrained Single-Layer Absorber, Ying-Chun Chang, Long-Jyi Yeh, Min-Chie Chiu, Gaung-Jer Lai

Journal of Marine Science and Technology–Taiwan

The thickness and the attached area of the sound absorber are confined in the practical engineering design while the sound absorber is applied inside the machine room to eliminate the reverberant sound energy. The optimization of the shape of the absorber and the quantification of the exact area of the absorber (in order to meet the required value of sound pressure level (SPL) at the concerned receiving point) becomes essential. For purposes stated above, two powerful gradient techniques with a logical control algorithm are applied during the optimization of the sound absorption system. Both the optimization of shape and the …

Go to article

Effects Of Viscous Shear Stresses On The Squeeze Films Of Porous Parallel Rectangular Plates, Jaw-Ren Lin, Long-Jin Liang, Rong-Fang Lu Apr 2004

Effects Of Viscous Shear Stresses On The Squeeze Films Of Porous Parallel Rectangular Plates, Jaw-Ren Lin, Long-Jin Liang, Rong-Fang Lu

Journal of Marine Science and Technology–Taiwan

Considering the effects of viscous shear stresses, a study of squeeze-film behavior between porous parallel plates with finite width is presented. Based upon the Brinkman model (BM), two general coupled Reynolds equations derived for curved surfaces [20] are applied to predict the two-dimensional squeeze-film pressure and thereafter the squeeze-film characteristics. The results show that the BM predicts quite different squeeze-film behaviors to those obtained by using the slip-flow model (SFM) and the Darcy model (DM). Comparing with the SFM, the viscous shear effects provide an increase in the load-carrying capacity and lengthen the response time of finite porous squeeze-film plates. …

Go to article

The Effects Of Couple Stresses In The Squeeze Film Characteristics Between A Cylinder And A Plane Surface, Jaw-Ren Lin, Won-Hsion Liao, Chi-Ren Hung Apr 2004

The Effects Of Couple Stresses In The Squeeze Film Characteristics Between A Cylinder And A Plane Surface, Jaw-Ren Lin, Won-Hsion Liao, Chi-Ren Hung

Journal of Marine Science and Technology–Taiwan

On the basis of the Stokes micro-continuum theory, the effects of couple stresses resulting from the lubricant blended with various additives upon the squeeze film behavior between a long cylinder and a plane surface are analyzed. Compared to the conventional Newtonianlubricant case, the couple stress effects characterized by the couple stress parameter signify an improvement in the squeeze film characteristics. Increasing values of the couple stress parameter increases the hydrodynamic load-carrying capacity and provides a longer time to prevent cylinder-plane surface contact. The approaching time of the cylinder in reducing the film thickness h m * = 1 to h …

Go to article

Discontinuous Conduction Mode Of Negative Output Elementary Circuit, Jung-Chien Li, Han-Yang Chen Apr 2004

Discontinuous Conduction Mode Of Negative Output Elementary Circuit, Jung-Chien Li, Han-Yang Chen

Journal of Marine Science and Technology–Taiwan

The negative output elementary circuit operated in the discontinuous conduction mode is discussed. The voltage transfer gain of this dc-to-dc converter depends on switching frequency, conduction duty ratio, inductance, and load resistance. The condition for the discontinuous conduction mode is derived and verified. The variation ratio of the output voltage is also derived.

Go to article

Response To Comments On "A Novel Approach To Determine The Astronomical Vessel Position", Jiang-Ren Chang, Chih-Li Chen, Tien-Pen Hsu Apr 2004

Response To Comments On "A Novel Approach To Determine The Astronomical Vessel Position", Jiang-Ren Chang, Chih-Li Chen, Tien-Pen Hsu

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Go to article

Magneto Rheological Dampers — A New Paradigm In Base Isolation Techniques In Earth Quake Engineering, S. Suresh Babu Apr 2004

Magneto Rheological Dampers — A New Paradigm In Base Isolation Techniques In Earth Quake Engineering, S. Suresh Babu

International Conference on Case Histories in Geotechnical Engineering

Over the past three decades, a great deal of interest has been generated regarding the use of structural protective systems to mitigate the effects of dynamic environmental hazards, such as earth quakes and strong wind, on Civil Engineering structures. These systems usually employ supplemental damping devices to increase the energy dissipation capability of the protected structure. One of the most promising new devices proposed for structural protection is Magneto rheological (MR) fluid dampers because of their mechanical simplicity, high dynamic range, low pressure requirements, large force capacity and robustness, this class of devices has been shown to mesh well within …

Go to article

Past Proceedings: 3rd International Conference On Recent Advances In Geotechnical Earthquake Engineering & Soil Dynamics (1995), Multiple Authors Apr 2004

Past Proceedings: 3rd International Conference On Recent Advances In Geotechnical Earthquake Engineering & Soil Dynamics (1995), Multiple Authors

International Conference on Case Histories in Geotechnical Engineering

No abstract provided.

Go to article

Restoration Of Path Service To Lower Manhattan, Raymond E. Sandiford, Samuel Leifer, Mark Mcneilly Apr 2004

Restoration Of Path Service To Lower Manhattan, Raymond E. Sandiford, Samuel Leifer, Mark Mcneilly

International Conference on Case Histories in Geotechnical Engineering

When the World Trade Center was destroyed the transit link connecting Lower Manhattan and New Jersey, the Port Authority’s Trans Hudson system or PATH, was cut. The PATH station, which was located beneath the WTC, was destroyed, the two tunnels under the Hudson River were flooded, and the first PATH station in New Jersey was rendered useless for train movements. Immediately after Sept 11, the re-establishment of the downtown PATH service was identified as a key element in the revitalization of Lower Manhattan. The re-establishment of PATH service required that three elements of major construction be completed. These were the …

Go to article

Non-Destructive Evaluation Of Deep Foundations, Frank Rausche Apr 2004

Non-Destructive Evaluation Of Deep Foundations, Frank Rausche

International Conference on Case Histories in Geotechnical Engineering

Non-Destructive Testing (NDT) or Non-Destructive Evaluation (NDE) of a great variety of materials and structures has become an integral part of many manufacturing processes. The same tendency towards more testing for improved quality assurance is also apparent in the deep foundation industry. However, the process of testing long piles, deeply embedded in the ground, is more complex than the NDE of other materials: the product can only be accessed from its smallest side and the material is often concrete or timber, which are rather heterogeneous materials with unreliable properties. The greatest difficulties, however, are presented by the intimate contact between …

Go to article

The Collapse Of Fukae (Hanshin Expressway) Bridge, Kobe, 1995: The Role Of Soil And Soil-Structure Interaction, George Mylonakis, Costis Syngros Apr 2004

The Collapse Of Fukae (Hanshin Expressway) Bridge, Kobe, 1995: The Role Of Soil And Soil-Structure Interaction, George Mylonakis, Costis Syngros

International Conference on Case Histories in Geotechnical Engineering

The paper investigates the role of soil in the collapse of a 630m segment (Fukae section) of the elevated Hanshin Expressway during the severe Kobe earthquake of 1995. From a geotechnical viewpoint, the earthquake has been associated with extensive liquefactions (notably of reclaimed ground), lateral soil spreading, and damage to waterfront structures. However, there is evidence that soil-foundation-structure interaction (SFSI) in non-liquefied ground played a detrimental role in the seismic performance of local structures, including the one under investigation. The bridge consisted of single circular concrete columns monolithically connected to a concrete deck, founded on pile groups in alluvium sand …

Go to article

Settlement Back-Analysis Of Buildings On Soft Soil In Southern Germany, H.-G. Kempfert, B. Soumaya Apr 2004

Settlement Back-Analysis Of Buildings On Soft Soil In Southern Germany, H.-G. Kempfert, B. Soumaya

International Conference on Case Histories in Geotechnical Engineering

This paper presents 10 case-histories of buildings on soft clay in southern Germany. A lot of field observations show that the calculated settlements using the routine analysis are on average 50 % larger than settlements actually measured in this area. A back-analysis is carried out to verify the soil parameters which are intended to investigate in the subsurface exploration phase and later in a laboratory test program. Recommendations for the engineering practice are suggested to review the determination of compressibility parameters and, consequently, to improve the settlement prediction.

Go to article

Design And Installation Of Foundations In Various Ground Conditions At Four Power Stations In The U.K., Christopher D. Parks, David E. Jones, José L. M. Clemente Apr 2004

Design And Installation Of Foundations In Various Ground Conditions At Four Power Stations In The U.K., Christopher D. Parks, David E. Jones, José L. M. Clemente

International Conference on Case Histories in Geotechnical Engineering

The design and installation of safe and economic foundation solutions for large projects is of great importance in contributing to commercial success. On four recent power projects in the U.K., a variety of foundation solutions have been adopted, driven largely by the particular ground conditions encountered at each location. All four projects were gas fired combined cycle power station facilities and each location provided unique challenges in both the design and installation of the foundations. The variety of foundation soils encountered was diverse; soft alluvial peat and clay, loose to medium dense silty sands and moderately weak to moderately strong …

Go to article

Design And Construction Of A Support Of Excavation System For A Deep Cut-And-Cover Tunnel In Downtown Boston, Yousef Alostaz, Abdol Hagh, Jack Pecora Apr 2004

Design And Construction Of A Support Of Excavation System For A Deep Cut-And-Cover Tunnel In Downtown Boston, Yousef Alostaz, Abdol Hagh, Jack Pecora

International Conference on Case Histories in Geotechnical Engineering

This paper presents the analysis, design, implementation and construction of a Value Engineering Cost Proposal (VECP) for the support of excavation system for parts of the underground Central Artery Tunnel in downtown Boston. The excavation varies between about 130 ft and 240 ft in width and between 60 ft and 100 ft in depth. The typical structure of the tunnel consists of soldier pile tremie concrete (SPTC) walls, roof girders with a cast-in place (CIP) concrete slab and a CIP invert slab. The SPTC walls, constructed using the bentonite slurry technique, act as the temporary earth-support structure as well as …

Go to article

Increase In Pile Capacity With Time In Missouri River Alluvium, Paul J. Axtell, Jacob W. Owen, Scott D. Vollink Apr 2004

Increase In Pile Capacity With Time In Missouri River Alluvium, Paul J. Axtell, Jacob W. Owen, Scott D. Vollink

International Conference on Case Histories in Geotechnical Engineering

The data measured in this study suggest that the increase in compressive pile capacity for a 42-ft long, HP14x102 pile, in a predominantly fine-grained Missouri River alluvium soil profile, increases by about 16 percent from days seven to forty-four after driving. It appears evident that Davisson’s (1973) failure criteria seems to agree fairly well with the observed plunging failure of two compressive pile-load failure tests performed in Missouri River alluvium. By comparison of compressive proof and failure tests performed on day forty-four after driving, it appears that loading a pile to some degree prior to failure, and then reloading the …

Go to article

Settlement Of A Light Rail Pier Supported On Large Diameter Bored Piles Remediated By Jet Grouting, Emilio M. Morales, Toshio Ono Apr 2004

Settlement Of A Light Rail Pier Supported On Large Diameter Bored Piles Remediated By Jet Grouting, Emilio M. Morales, Toshio Ono

International Conference on Case Histories in Geotechnical Engineering

A support Pier (Pier 161) for a Light Rail line being constructed for the Metro Manila Light Rail Project encountered large settlements after the installation of the Precast Deck Girders. This pier supports bridge crossing across the San Juan River with a total span of sixty (60) meters. This Pier is supported on six (6) 1500 mm diameter bored piles designed to extend down to 17 meters or socketed into bedrock at least 2.0 meters based on design requirements. The structure started to settle during the erection of the superstructure when the dead load reached about 700 metric tons. Total …

Go to article

First Prev Next Last