Digital Commons Network^™

Q Improvement Of A 5.2 Ghz Te011 Cavity By Incorporating Y1Ba2Cu3O7-X, R. Joseph Leclear

Electrical & Computer Engineering Theses & Dissertations

Research is undertaken to apply high temperature superconducting material to improve the quality factor (Q) of a 5.2 GHz cylindrical resonant cavity. In particular, the approach is to electrophoretically deposit polycrystalline Y₁Ba₂Cu₃O_7-x (YBCO) on the conducting surface of the cavity cylinder. Spalling of the YBCO ceramic coating due to expansion and contraction of the cavity during sintering and testing is overcome by segmenting the cylinder. Results show that the Q of the cavity is increased over that of a copper cavity at temperatures below 60 K. At 20 K, improvement exceeds a factor …

Simulator For Concurrent Processing Data Flow Architectures, Mahyar R. Malekpour

Electrical & Computer Engineering Theses & Dissertations

A software simulator capable of simulating execution of an algorithm graph on a given system under the Algorithm To Architecture Mapping Model (ATAMM) rules is presented in this thesis. ATAMM is capable of modeling the execution of large-grained algorithms on distributed data flow architectures. Investigating the behavior and determining the performance of an ATAMM based system requires the aid of software tools. The ATAMM Simulator presented in this thesis is capable of determining the behavior, performance, and reliability of a system without having to build a hardware prototype. Case studies are performed on four algorithms to demonstrate the capabilities of …

Afit/Afosr Symposium On Applications Of Wavelets To Signal Processing, Volume Ii, Tutorial Notes, Gregory T. Warhola, Mark E. Oxley, Steven K. Rogers, Matthew Kabrisky, Bruce W. Suter

AFIT Documents

The Air Force Institute of Technology (AFIT) hosted the Symposium on Applications of Wavelets to Signal processing during 20-22 March 1991 at the AFIT Science and Research Center, Wright-Patterson AFB, OH. This was the first major academic meeting of its kind held at AFIT. The symposium was sponsored by the Air Force Office of Scientific Research (AFOSR), Bolling AFB, DC. It focused on applications of wavelets to problems in image and speech processing, communications, and graphics and opened with a one-day short course, 'A Tutorial on Wavelets.' The symposium was attended by more than 220 researchers worldwide. They represented 15 …

Guerrero Accelerograph Array: Status And Selected Results, J. G. Anderson, A. Mendez, R. Quaas, J. N. Humphrey, R. Castro, S. K. Singh

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper summarizes the history and rational for installation of the Guerrero accelerograph array. The array is producing unprecedented quantities of high quality digital strong motion data. Recent research using the array data has included studies on attenuation, site effects, scaling of spectra with magnitude, the ratio of vertical to horizontal accelerations, and the source of the September 19, 1985 earthquake.

Seismic Risk Analysis For A Site Along The Gorda Segment Of The Cascadia Subduction Zone, Ronald C. Chaney, Guy Conversano, Gary Carver, David N. Lindberg, Frank Bickner

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A seismic risk evaluation was conducted on a site near Eureka, California. The site was subject to potential earthquake loading from a number of sources. These sources were: (1) Mendocino Fracture Zone, (2) Gorda Segment of the Cascadia Subduction Zone, (3) Little Salmon thrust fault under the site, (4) Mad River Fault Zone, and (5) Intra plate west - Gorda Plate. The geology of thrust faults in Northern California is examined along with that of the Mendocino Fracture Zone, and the southern section (Gorda Segment) of the Cascadia subduction zone. A trench log showing a splay of the Little Salmon …

Earthquake Potential Along The Hayward Fault, California, Glenn Borchardt, J. David Rogers

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The Loma Prieta event probably marks a renewed period of major seismic activity in the San Francisco Bay Area. Particularly ominous is the historic record of major events a few years apart on opposite sides of the Bay in 1836 (N. Hayward fault) and 1838 (N. Peninsula, San Andreas fault) and 1865 (Loma Prieta segment, San Andreas fault), and 1868 (S. Hayward fault) (Figure 1). Recent preliminary measurements of the Holocene geologic slip rate of the Hayward fault are as much as 9 mm/yr (Lienkaemper and others 1989) - about 80% greater than the first Holocene measurements determined as recently …

Prediction Of Loma Prieta Earthquake And Creation Of Awareness About It In Society, Arun Bapat

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Prediction of earthquake as an exercise of academic interest is one activity. Creation of awareness about seismic disaster and its mitigation is more broad base social activity. It is necessary that the predicted seismic event is likely to occur, people in the vulnerable seismic area should be told about the utility of macroseismic, short-term reliable earthquake precursors, which could be observed by common man. The happenings involving both the above cases for Loma Prieta earthquake are discussed.

Verification By Comparison Between Static And Dynamic Engineering Soil Parameters Evaluated By Means Of Box Tests, Jan Bencat

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A conventional track structure system consists of rails, ties, ballast, subballast and subgrade. To design a track on the basis of live load response and permanent settlement, it is necessary to have knowledge of dynamic stresses in the foundation layers of the track. It needs to determine the material properties and thus, the dynamic and permanent deformation response of the track structure. This paper gives results of the experimental measurements of static and dynamic engineering soil parameters evaluated by means of box tests, Bencat 1989.

Seismic Design Of Rigid Underground Walls In New England, Cetin Soydemir

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The Mononobe-Okabe equation is still widely used in design practice to estimate earthquake induced soil pressures against earth retaining structures without differentiation of the lateral yielding or non-yielding character of the structure. Where these structures are rigid and non-yielding because of structural restraints (e.g., basement walls, bridge abutments, underground transportation, hydraulic and sanitary structures) the use of Mononobe-Okabe equation would not be appropriate and would be generally unsafe. Alternate design recommendations are proposed, based on the results of recent analytical and experimental studies by other researchers, for a nominal design earthquake expected to be representative of the New England seismicity.

Energy Approach For Liquefaction Of Sandy And Clayey Silts, Y. L. Cao, K. T. Law

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The liquefaction potential of sandy and clayey silts is assessed in this paper using an energy approach original developed for sand. Three series of laboratory tests were conducted to examine the liquefaction resistance of clean silt, sandy silt and clayey silt. The test results have been analyzed to establish a liquefaction failure criterion for silty soils. Based on this criterion, the case records of a new database have been studied and the results suggest that a single criterion can be used for sand, silt, sandy silt and clayey silt. For sandy or silty soils without clay content, the criterion is …

Geotechnical Damage Due To Bihar Earthquake Of August 1988, Sudhir K. Jain, Anil K. Agrawal, Raghunath P. Tripathi

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The Bihar-Nepal earthquake of August 21, 1988 (magnitude 6.6) caused significant loss of life and property. Besides the epicentral area, two distant places (Munger in India and Bhaktapur in Nepal) suffered significantly. This was also the case in the 1934 earthquake (magnitude 8.4) and is due to peculiar geology of the area. Geotechnical damage in the affected area includes liquefaction, cracking and subsidence of embankments, and cracks in bridge abutments and wing walls. Besides, in the hilly regions of Sikkim, landslides and rockfalls disrupted road network significantly. Extensive damage took place in the eastern Nepal also. This paper describes the …

A Model For Predicting Liquefaction Induced Displacement, Peter M. Byrne

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A simple model for predicting liquefaction induced displacement is presented. The method is based on a single-degree-of-freedom system that incorporates the post-liquefaction stress-strain response of sand. The key parameters are the residual strength and the limiting shear strain, and considerable data presently exists on these two parameters from correlation with SPT (N₁)₆₀ values. Based on this data, liquefaction induced displacements from the model are compared with both field and laboratory measurements. The model predictions are found to be in excellent agreement with the measurements and indicate that liquefaction induced displacements are very sensitive to the density or …

The Optimization Principles Of The System "Mass Blast-Protected Structure", Yugeni Borisov, Boris Pishkin

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The real work is ideological result of the investigations, which have been carried out for 25 years, on structural dynamics under the seismo-explosive loads, induced by industrial and experimental blasts, simulating natural earthquakes, and on the optimization parameters of drill explosive works in the mining quarrels.

Ground Failure During Loma Prieta Eq - Downtown Santa Cruz, Alan Kropp, Michael Thomas

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Ground failure occurred in numerous locations in the downtown Santa Cruz area during the Lorna Prieta Earthquake. These failures included liquefaction, lateral spreading and lurch cracking. Mapping of many of these features was made within three days of the earthquake, before heavy rains obscured much of the surface evidence. Data from a United States Geological Survey study of liquefaction potential in Santa Cruz has been examined. In addition, subsurface information has been collected from several downtown subsurface exploration studies. A comparison has been made between areas where ground failure was predicted and where it occurred during the Lorna Prieta Earthquake. …

Classification Of Analysis Methods For Dynamic Soil-Structure Interaction, John P. Wolf

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The various methods to perform soil-structure-interaction analysis are classified. The first classification uses as criterion the behavior (linear or nonlinear) of the structure and of the unbounded soil. The second classification distinguishes between the direct method and the substructure method, which do not necessarily lead to identical results. Within each method, however, the various procedures are mathematically equivalent. In the substructure method the dynamic stiffness representing the interaction forces of the unbounded soil is determined based on the boundary element method in the time or frequency domain. In the latter case various so-called realizations in the time domain are distinguished …

Seismic Design Of Earth Retaining Structures, R. V. Whitman

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Recent experiments, field observations and theoretical numerical studies are summarized: Where the simple conditions assumed by the Mononobe-Okabe theory are reproduced. ln tests, predictions and observations agree well. However, a retaining structure and surrounding soil are a complex dynamic system and behavior is far from simple. Emphasis has shifted somewhat away from dynamic stresses toward evaluation of residual displacements. With a good understanding of actual behavior, traditional methods may still be used except for large and unusual structures. The largest unknowns concern the behavior of cohesive soils and moderately dense to dense saturated sands.

Earthquake Probabilities On The New Madrid Fault And The Impact Of Loma Prieta On Central U.S. Earthquake Preparedness, David Stewart

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Reliable probabilities of future damaging earthquakes in the New Madrid Fault Zone for purposes of mitigation and response planning are not available, even though considerable thought and research has gone into this question. Generalizations sufficient for pre-earthquake planning do exist, however, which suggest the need to prepare for at least a 50% chance of a 6.0 surface wave magnitude event within a decade, but that a repeat of the massive 8.0 magnitude events of 1811-12 need not be of concern for at least another century or two. The Loma Prieta was a significant stimulus toward greater earthquake planning and preparation …

Lumped-Parameter Model For Foundation On Layer, John P. Wolf, Antonio Paronesso

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A lumped-parameter model to represent a disk on the surface of a layer built-in at its base vibrating in horizontal, vertical, rocking or torsional motions is presented. Eight frequency-independent real coefficients determine the springs, dampers and the mass of the lumped-parameter model with two internal degrees of freedom. These coefficients are specified for various ratios of the radius of the disk to the depth of the layer and for various Poisson's ratios. To derive the mechanical properties of the lumped-parameter a systematic procedure of curve-fitting of the dynamic-stiffness coefficient up to at least twice the fundamental frequency of the layer …

Soil-Structure Interaction Effects On The Response Of Meloland Bridge, E. A. Maragakis, S. Vrontinos, B. M. Douglas, S. Abdel-Ghaffar

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A study related to the experimental data obtained from the full-scale tests of Meloland Road overcrossing is presented. The major objective of this study is to demonstrate that the soil structure interaction effects play a significant role in the dynamic response of the structure. Initially, the results from the static deformation of the bridge under the quick-release loads are presented. These results were obtained by applying a special integration technique on the experimental acceleration records. Then a preliminary analytical model of the bridge is fitted to the experimental data in order to evaluate the values of the soil-structure springs along …

The Soil-Structure Interaction In Bridge Dynamics Problems, E. V. Berezantseva, A. M. Uzdin, Yu. G. Kozmin

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

At the Bridges Department of Leningrad Institute of Railway Communication Engineers complex investigations of bridge dynamics under the seismic and rolling stock loads had been carried out. It is ascertained that for theoretical description of bridge oscillations the question of "piers-base" interaction is a matter of principal importance. During the process of oscillations there is a loss of energy due to the radiation by the propagation of elastic waves in the soil. These losses of energy considerably exceed the hysteresis ones, especially for bridges with metal span structures. Researches carried out allowed to make the theoretical estimation of the general …

Performance Of A Hazardous Waste And Sanitary Landfill Subjected To Loma Prieta Earthquake, Hari D. Sharma, Harish K. Goyal

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Loma Prieta Earthquake of October 17, 1989 caused severe damages in the San Francisco Bay Area. Field measurements made during the earthquake and analyses performed to date indicate that bedrock accelerations were amplified to 2 to 3 times in propagating through deep cohesive deposits. In view of this, the performance of a hazardous waste and sanitary landfill subjected to Loma Prieta Earthquake and founded on deep cohesive deposits was evaluated. Analyses indicate that the peak accelerations at the base of the refuse are slightly amplified in propagating through the refuse thicknesses of up to about 50 feet. For higher refuse …

The Liquefaction Sand Boils In The San Francisco Marina District During The 1989 Loma Prieta Earthquake, J. P. Bardet, M. Kapuskar

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The paper presents and analyzes the observations of the sand boils that emerged in the Marina District after the Loma Prieta Earthquake of October 17, 1989. The sand boils left behind by liquefaction revealed an old lagoon, the periphery of which had experienced severe damage in the 1906 San Francisco earthquake. The buildings in the Marina District were damaged primarily as the liquefied ground spread laterally along the shoreline of the 1906 lagoon that was filled to host the 1915 Panama-Pacific International Exposition in San Francisco. The present work infers that the sand boils are not random phenomena but instrumental …

Geotechnical Lessons Learned From Mexico And Other Recent Earthquakes, Emilio Rosenblueth, Efrain Ovando

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper describes the most relevant effects of the September 1985 earthquakes on Mexico City. It discusses the results of recent exploration and research on regional geology, local site conditions and site response analyses, basic soil properties, and observation of actual behavior of soil-foundation-structure systems. The paper shows the impact of these investigations upon new - building code requirements, on general design practice and on the specialist's perception of earthquake behavior of Mexico City's subsoil. Recent earthquakes recorded in and around Mexico City have contributed insight into some of the unresolved questions left after the experience of 1985. Damaging earthquakes …

GMax From Pressuremeter Tests: Theory; Chamber Tests; And Field Measurements, Peter M. Byrne, Francisco Salgado, J. A. Howie

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A method of analysis to predict the in situ maximum shear modulus G_max,0 from self-boring pressuremeter unload tests is presented. The method considers both the stress and void ratio changes induced by pressuremeter loading and the nonlinear stress-strain response upon unloading. The results are presented in the form of a chart that allows G_max,0 to be determined from the equivalent elastic unload modulus, G*, for a wide range of loading and unloading conditions. The analysis procedure is checked with chamber tests and field data and the results are found to be in good agreement provided factors to account …

Phase Separation In Glasses, N. J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

The detection, acceptance and further investigation of glass-glass phase separation was closely connected with the development of methods making detection possible, such as electron microscope technique pioneered and exploited by Werner Vogel, to whom this paper is dedicated on the occasion of his 65th birthday. Structures are not always found in agreement with rules derived from thermodynamic principles, and also depend on thermal history, as well as mode of preparation. The phenomenon is exemplified in many glass-forming systems. Among more recent applications are the control of crystallization by preceding phase separation as in glass-ceramics and semiconductor-doped glasses for non-linear optics. …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, March 1991, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A twelve page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Acuta Enews March 1991, Vol. 20, No. 3

ACUTA Newsletters

In This Issue

Telecom graduate study

Greenville Tech outgrows PBX

World-calling discounts

Call for Presentations

Update on Hawaii

Listing of exhibitors

Hiro Kurashina's Review Of William N. Morgan's Prehistoric Architecture In Micronesia, Hiro Kurashina

Pacific Studies

No abstract provided.

A Common Interface Real-Time Multiprocessor Operating System For Embedded Systems, Michael S. Rottman

Theses and Dissertations

Large real time applications such as aerospace avionics systems, battle management, and factory automation place many demands and constraints on the computing system not found in other applications. Software development is hindered by software dependence on the computer architecture and the lack of portability between systems. This thesis specifies and designs a real time multiprocessor operating system (RTMOS) that implements a consistent programming model, enabling the development of real time parallel software independent of the target architecture. The RTMOS defines the core functionality required to demonstrate the programming model. The RTMOS functional requirements are specified using Structured Analysis and Design …

Optimal Iterative Task Scheduling For Parallel Simulations, Joann M. Sartor

Theses and Dissertations

The ultimate purpose of this research is to reduce the time needed for execution of parallel computer simulations. In particular, the impact of task assignment strategies is determined for parallel VHDL circuit simulations. The classical scheduling problem, which assigns n precedence-constrained tasks to m processors is NP-complete in all but the simplest cases. The problem of assigning simulation tasks is further complicated by the iterative nature of computer simulations: each task is required to execute multiple times as the simulation executes. This investigation develops a polynomial-time algorithm (the level strategy) which provides optimal assignment for iterative systems with specific constraints. …