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Conferences, Lectures, & Seminars
Events for November
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Effect of Phase Spectrum Uncertainties of Earthquake Motion on Seismic Fragility Curve of Steel Brid
Tue, Nov 01, 2005 @ 11:00 AM - 12:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
*BY
*Prof. Tadanobu Sato
*Faculty of Science and Engineering
Waseda University
satotdnb@aoni.waseda.jpAbstract:* The earthquake resistant capacity of a structure with uncertainties is evaluated by fragility curves based on the probabilistic concept. We estimate fragility curves by using Monte Carlo simulation (MCS) and limit seismic intensity. For the effective estimation of the tail part, namely low conditional failure probability, we use the Subset simulation method. Samples are generated to search the failure region in each subspace by using Markov Chain Monte Carlo (MCMC). The effect of phase spectrum uncertainties on the fragility curve is also examined and a method to define a design earthquake motion eliminating phase uncertainties.
Location: Kaprielian Hall (KAP) - 203
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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A Portable Continuous Desulfurization Unit for Diesel
Fri, Nov 11, 2005 @ 01:00 PM - 02:00 AM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:Meng-Wei Wan, PhD Candidate
Department of Civil and Environmental Engineering
University of Southern CaliforniaAbstractDue to the stringent rules requiring ultra-low sulfur content in diesel fuels, it is necessary to develop alternative methods of desulfurization of fossil fuel derived oil, such as diesel. Current technology is not sufficient to solve this problem. The ultrasound assisted oxidative desulfurization process (UAOD) which combines three complementary techniques: ultrasonication, phase transfer catalysis and transition metal catalyzed oxidation, has accomplished high sulfur removal in a short contact time at ambient temperature and atmospheric pressure. For diesel fuels containing various levels of sulfur content, the UAOD process followed by solvent extraction has demonstrated that the sulfur reduction can reach above 95 % removal efficiency or a final sulfur content below 15 ppm in mild conditions.
For large-scale commercial production, this research has successfully developed and operated a continuous desulfurization unit, which consists of a sonoreactor, an RF amplifier, a function generator, a pretreatment tank, and a pipeline system. A single unit only requires about 2` x 4` x 1` space for installation. The results indicate a remarkable 92% removal efficiency for sulfur in marine logistic diesel, even at a treatment rate as high as 25 lb/hour, which is approximately 2 barrels per day. Therefore, the sonoreactor unit demonstrated the feasibility of large-scale operation even in a relatively small installation with low capital investment and maintenance cost. It also ensures the safety considerations by operating with diluted hydrogen peroxide under ambient temperature and atmospheric pressure.Location: Kaprielian Hall (KAP) - 156
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Ship Shock Trial Modeling and Simulation
Wed, Nov 16, 2005 @ 03:30 PM - 04:30 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:Young S. Shin, Ph.D.
Department of Mechanical and Astronautical Engineering
Naval Postgraduate School
Monterey, California 93943
(831) 656-2568, yshin@nps.eduAbstract
During World War II many surface combatants were damaged or severely crippled by close-proximity underwater explosions from ordnance that had actually missed their target. Since this time all new classes of combatants have been required to conduct shock trial tests on the lead ship of the class in order to test the survivability of mission essential equipment in a severe shock environment. While these tests are extremely important in determining the vulnerabilities of a surface ship, they require an extensive amount of preparation, man-hours, and money. Furthermore, these tests present an obvious danger to the crew on board, the ship itself, and any marine life in the vicinity. Creating a virtual shock environment by use of a computer to model the ship structure and the surrounding fluid presents a valuable design tool and an attractive alternative to these tests. The research work shown in this paper investigated the accuracy of shock simulation using the shock trials conducted on DDG class ship. The ship shock modeling and simulation strategy is discussed and the effects of fluid volume size, mesh density, mesh quality are also investigated.
Location: Stauffer Science Lecture Hall, Room 102
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Thermal Remediation of Creosote and Pentachlorophenol in a Heterogeneous Stratigraphy
Fri, Nov 18, 2005 @ 01:00 PM - 02:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:Craig L. Eaker, Ph.D.
Southern California Edison
Rosemead,CA
craig.eaker@sce.comAbstractThe presentation is a case study of the results of the Visalia Steam Remediation Project (VSRP) conducted May 1997 through June 2000. The present laboratory data demonstrates success in achieving the project goal of restoring the groundwater quality to meet the regulatory standards. During 36 months of field operations, approximately 660,000,000 pounds of steam was injected into the formation to thermally treat 375,000 yards of contaminated material. About 1,330,000 pounds of a mixture of Creosote, Diesel, Pentachlorophenol, and Dioxins were extracted as vapors and liquids, or were chemically oxidized in the formation. Currently the groundwater at the "Point of Compliance" meets the Remediation Standards as specified by the California EPA, Department of Toxic Substance Control (DTSC). The groundwater assays in this vicinity have produced results which comply with the Remediation Standards for Pentachlorophenol (1 ug/L), Benzo(a)Pyrene (0.2 ug/L), and TCDDeqv (30 pg/L).The presentation will graphically represent six years of groundwater assays which clearly demonstrate the effectiveness of a thermal remedy to restore groundwater, adversely impacted by wood preservative chemicals, to a drinking water quality. Additionally, "best practices" for steam reservoir management and empirical observations of in-situ oxidation and saponification of wood preservative chemicals will be presented.Location: Kaprielian Hall (KAP) - 156
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Polycrystalline modeling of fcc materials under changes in strain path
Mon, Nov 28, 2005 @ 11:00 AM - 12:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:Irene Beyerlein
Theoretical Division, Los Alamos National Laboratory
Los Alamos, NM 87545, USAAbstractStudies show that when the load path is changed, the stress-strain behavior of a polycrystalline metal highly depends on the texture (the distribution of crystallographic orientations of the crystals) and microstructures that developed during the pre-straining. Particularly when the pre-strains are large, texture and microstructural evolution within individual crystals become heterogeneous, potentially inducing noticeable changes in the macroscopic flow response when the direction of loading is changed. At Los Alamos, we are developing a constitutive model for fcc materials under strain path changes, including reversals of the applied load (leading to a drop in yield stress, the so-called Bauschinger effect) and straining in directions normal to the pre-strain (leading to an increase in yield stress, a cross-effect). The model accounts for both texture evolution and several microscale mechanisms responsible for the possible directional anisotropy in the single crystals. These mechanisms include the formation of dislocation microstructures preferentially on slip planes, localized destruction of such microstructures generated by channeling dislocations activated in subsequent strain paths, and the release of polar dislocations when slip is locally reversed. We apply this model to predict the response under Bauschinger tests, in which the direction of axial loading is reversed. As a more complex example, we also apply our model to predict the subsequent flow stress in pure copper processed by equal channel angular extrusion (ECAE), a process which imposes severe plastic shear strains.Location: Kaprielian Hall (KAP) - 203
Audiences: Everyone Is Invited
Contact: Evangeline Reyes