Select a calendar:
Filter October Events by Event Type:
Conferences, Lectures, & Seminars
Events for October
-
ENSEMBLE UNCERTAINTY QUANTIFICATION
Tue, Oct 03, 2006 @ 11:00 AM - 12:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:Dr. Steven F. Wojtkiewicz
Department of Civil Engineering
University of Minnesota
ykvich@umn.edu Abstract:
This presentation addresses the need for the development of uncertainty quantification algorithms that leverage information from one realization to another. Although the size of the computational models used in many engineering and scientific simulations is extremely large, i.e. millions of equations, the uncertainty to be analyzed is oftentimes very localized to small regions of the model. One example of this manifests itself in a study of the effects of damping in connections between structural dynamic subsystems. While the full analysis model for this system is on the order of a million degrees of freedom, the nodes involved in an uncertainty analysis of the connection is on the order of ten. Here, recent efforts to explore, expand, and develop UQ methods that exploit this localization of uncertainty will be discussed.
Algorithms for linear algebraic and dynamic systems have been developed and will be outlined. In addition, their efficacy will be demonstrated through several examples. These algorithms utilize linear algebra techniques for low rank matrix updates, Sherman-Morrison-Woodbury formulas, and their dynamical analogs. The computational procedure consists of a small number of full system runs, the number of nodes involved in the connections in the abovementioned scenario. The solutions from this small number of runs are then used to construct a solution update procedure where the remaining computation for each realization involves a system solution of this greatly reduced size.
The ratio of the cost of each subsequent realization after these initial calculations to a full system solution is on the order of the ratio of the number of degrees of freedom of the full system model to that involving uncertainty. Thus, one can expect speedups of several orders of magnitude for the subsequent realizations. In addition, the system updates, due to the small systems being solved, can be performed using a wider variety of computing resources.
It is foreseen that the greatly increased number of realizations can be used to obtain greater fidelity in failure assessments (smaller failure probabilities) and/or to address the epistemic uncertainty issue by considering alternate plausible uncertainty models, including interval models, for the parameters being studied.Prof. Steve Wojtkiewicz received his Ph. D. in Aeronautical and Astronautical Engineering in 2000 from the University of Illinois at Urbana-Champaign. After graduating, he joined Sandia National Laboratories in Albuquerque, New Mexico where he was a member of the technical staff in the Structural Dynamics Research Department from 2000-2004. He held research appointments at Johns Hopkins University and the University of Southern California before joining the faculty at the University of Minnesota in the Department of Civil Engineering in August 2005. His research interests include the optimization, dynamic analysis and control of large structural systems and the development of uncertainty quantification and validation algorithms for large computational models.Location: Kaprielian Hall (KAP) - 203
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
-
The Health Effects of Combustion-Generated Particles
Wed, Oct 04, 2006 @ 03:30 PM - 04:30 AM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
JOINT SEMINAR with AME and CEE Speaker:
Ian M. Kennedy
Department of Mechanical and Aeronautical Engineering
University of California DavisAbstract
The link between exposure to fine particles in the atmosphere and adverse
health effects has been well-established by epidemiological studies. Most of
the fine and ultrafine material of concern derives from combustion sources
and is largely a mixture of elemental and organic carbon, metals, and
inorganic compounds such as sulfates. When inhaled by people, the particles
can be taken-up by cells in the lung. The particles can also penetrate into
the circulatory system and lodge in organs such as the liver and heart. The
mechanism for their impact on health is not entirely understood although the
generation of reactive oxygen species such as the OH radical is a major
focus. The inflammation that can be caused by these reactive species can
exacerbate pre-existing ailments. Combustion conditions in mobile and
stationary sources can affect the reactivity of aerosols and their ability
to generate reactive oxygen species. Combustion conditions can also affect
the speciation of transition metals, the morphology of particles and their
composition, and their size, all parameters that may lead to adverse health
effects. This presentation will review the current state of knowledge about
sources, transport, transformation and fate of fine and ultrafine particles
that arise from combustion sources. The impact of combustion conditions on
the potential for adverse health impacts will be given particular attentionWednesday, Oct. 4th
Stauffer Science Lecture Hall (SLH), Rm 100
3:30 pmRefreshments will be served at 3:15 pmLocation: John Stauffer Science Lecture Hall (SLH) - - Room100
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
-
Total Maximum Daily Loads as a Tool for Environmental Regulation and Improvements in Water Quality
Fri, Oct 06, 2006 @ 01:00 PM - 02:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:Dr. LB Nye
California Regional Water Quality Control Board
Los Angeles RegionAbstractThe calculation and implementation of Total Maximum Daily Loads (TMDLs) are an important tool for improving water quality in California. A TMDL is a calculation of the total amount of a pollutant which can be discharged to a waterbody without the waterbody exceeding water quality standards. In the development of a TMDL, that total amount will then be allocated to the various sources of the pollutant and other regulatory tools, such as wastewater discharge permits, will conform to those allocations. While the Clean Water Act (CWA) in 1972, required the development of TMDLs, that provision of the CWA was largely ignored by the USEPA and States until the 1990s when a series of legal actions focused new attention on the use of TMDLs. The Los Angeles Regional Water Quality Control Board (Regional Board), one of nine Regional Water Quality Boards of the State of California, has been developing and implementing TMDLs since 2001. TMDLs developed by the Regional Board have addressed metals, pesticides, chloride, pathogenic bacteria and nutrients among other contaminants. The development of TMDLs is both a technical and political process and is rarely straightforward. The Regional Board remains committed to the appropriate use of TMDLs as a tool to effect real improvement in water quality in the Los Angeles Region
Location: Kaprielian Hall (KAP) - rielian Hall, Room156
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
-
Burned Hillslopes + Fire = Mud: An Approach for Assessing Post-wildfire Debris-Flow Hazards
Wed, Oct 11, 2006 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:Dr. Susan H. Cannon
U.S. Geological Survey
Denver, COAbstract: Debris flows can be one of the most hazardous consequences of rain on recently-burned hillslopes. The deaths of sixteen people during the Christmas Day 2003 storm that impacted recently-burned hillslopes in southern California highlight the most drastic consequences of post-wildfire debris flows. The enhanced occurrence of catastrophic wildfires in the western United States, and the encroachment of development into fire-prone ecosystems, has resulted in the need for tools and methods to identify and quantify the potential hazards posed by debris flows from burned watersheds. In this talk I will describe an approach developed to answer some of the questions fundamental to post-fire debris-flow hazard assessments- what is the process? where might debris flows occur? how big will the event be? and how often will debris flows be produced? Evaluation of the response of basins burned by the fall of October of 2003 fires in southern California to the Christmas Day storm provides valuable information on ways to improve the approach. Biography: Sue Cannon has Masters degrees in geology and civil engineering from the University of Colorado, and a PhD from the University of Colorado. She has been a researcher with the U.S. Geological Survey Landslide Hazards Program since 1990, and has been working on issues dealing with the generation of fire-related debris flows since 1994. Her primary focus is the development of tools and methods for defining fire-related debris-flow hazards, and although she has had research projects in Montana, Idaho, Colorado, New Mexico, her focus is now on southern California. She finds it hard to stay away from a good fire.Location: Kaprielian Hall (KAP) - rielian Hall , Room 203
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
-
Fuel Cell Grade Diesel Processed by Ultrasound-Assisted oxidative Desulfurization Technology
Fri, Oct 13, 2006 @ 01:00 PM - 02:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Environmental Engineering SeminarOmid Etemadi, Ph.D. Candidate
Environmental Engineering
University of Southern CaliforniaAbstractUltrasound-Assisted Oxidative Desulfurization (UAOD) process has been improved for practical use by substituting solid adsorption with solvent extraction. Therefore the advantages of both oxidative and adsorptive desulfurization have been put together for an enhanced continuous system. A tailor-made modular sonoreactor was used in a portable unit of continuous flow system with a fixed-bed adsorbent. The whole system operates at ambient temperature and atmospheric pressure. Alumina is used for removing the oxidized sulfur compounds in MGO marine logistic diesel and JP-8 jet fuel diesel. For the same sulfur removal much lower alumina is needed than the liquid solvent for extraction. For achieving a green chemistry, the recovery of the adsorbent was through calcining instead of using organic solvents for regeneration of alumina. Tests on model compounds prove the selectivity of alumina in adsorption. Scale-up tests have promising results for industrial use of the system.This presentation focuses on sulfur removal in certain diesel fuels and the results support the selective nature of oxidation and adsorption. Chromatograms from sulfur chemiluminescence detector (GC-SCD) and pulsed flame-photometric detector (GC-PFPD) show the levels of removal down to ultra-low sulfur diesel. Images from scanning electron microscopy (SEM) and results of small angle neutron scattering (SANS) for different phases of alumina clarify the characteristics of the adsorbents.Location: Kaprielian Hall (KAP) - 156
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
-
Vehicle Testing at the California Air Resources Board
Fri, Oct 20, 2006 @ 01:00 PM - 02:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:
Edward Sun, P.E.
Staff Air Pollution Specialist
Air Resources Board
El Monte, CAAbstractSouthern California has been known as the smog capital of the United States. With the San Gabriel Mountains blocking natural air flow, the contaminants in large amount of automobile exhaust are triggered by sunlight in a Mediterranean climate to form ozone that causes public health issues ranging from allergies, asthma attacks, difficulties in breathing, to premature deaths. After decades of efforts in new regulations, the ozone level has been significantly reduced, mostly through technologies implemented in modern automobiles. In addition to ozone, other air contaminants, such as particulate matter and greenhouse gases, are starting to receive more attention in recent years. This presentation will introduce the California Air Resources Board's Low-Emission Vehicle program, Fleet Greenhouse Gas Reduction program, and Vehicle Testing, which includes Electric Vehicle testing, Hybrid Electric Vehicle testing, Plug-In Hybrid Vehicle testing, and Hydrogen Fuel Cell Vehicle testing.
Location: Kaprielian Hall (KAP) - rielian Hall, Room 156
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
-
Got SSRP Citys 60 Mile-Program to Rehabilitate the Old Sewer Pipes
Fri, Oct 27, 2006 @ 01:00 PM - 02:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:
Tahir Upshur
Civil EngineerCity of Los Angeles
Department of Public Works
Bureau of Engineering
Wastewater Conveyance Engineering DivisionAbstractThe Bureau of Engineering (BOE) and Sanitation (BOS) had embarked on an effort to systematically review and study the secondary sewer system throughout the City of Los Angeles, which is programmed to assess its physical and hydraulic conditions and predict the future needs of the wastewater capital improvement. This is so-called, "SSRP (Secondary Sewer Renewal Project) 60 Mile-Program." The secondary sewer system consists of approximately 220 separate sewer sheds with sewers less than 16 inches in diameter. The basic planning strategy is to evaluate the sewers in priority order using ranking and defect categories, maintenance history, pipe age, material, spill history, and other factors. Based on this data base including CCTV of sewer pipes, BOE engineers do the decision making process whether the sewer should be rehabilitated by way of lining or spot repair. The 60 miles of sewer lines would be renewed to correct the current situation where leaking and non-functioning pipes are prevalent.
Location: Kaprielian Hall (KAP) - 156
Audiences: Everyone Is Invited
Contact: Evangeline Reyes