Conferences, Lectures, & Seminars
Events for December
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Vibration Mitigation of Nonlinear Structures using Nonlinear Energy Sinks
Thu, Dec 06, 2007 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:
Mr. Régis Viguié,
Ph.D. Candidate,
Aerospace and Mechanical Engineering Department,
University of Liège,
Liège, BelgiumAbstract:The tuned mass damper (TMD) is a simple and efficient device but it is only effective when it is precisely tuned to the frequency of a particular vibration mode. Because nonlinear vibrating structures have resonant frequencies that vary with the total energy in the system, the efficiency of a TMD is questionable in this case. In order to overcome this limitation, the nonlinear energy pumping phenomenon from the main mechanical structure to a coupled, local, passive nonlinear energy sink (NES) is investigated. It is shown that, unlike the TMD, an NES has no preferential resonant frequency, which makes it a good candidate for vibration mitigation of MDOF linear or nonlinear vibrating structures. In this presentation, the essential features of an NES will be described. Some potential applications of nonlinear energy pumping, including vibration absorption in drill-string systems and aeroelastic instability suppression, will be presented. Finally, the determination of a suitable design for the NES will also be discussed as well as some possible realizations of this nonlinear absorber.
Location: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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An Air Quality Engineer in Industry
Fri, Dec 07, 2007 @ 01:00 PM - 02:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:
Patricia G Menjivar,
Senior Environmental, Health and Safety Engineer,
Environmental, Health and Safety,
Space and Airborne Systems,
Raytheon Company,
El Segundo, CaliforniaAbstract:California's air pollution control program is one of the most effective in the world. California legislature is continuously in the forefront of newly created air quality regulations that affect not just California but the Nation. Industry in California must keep abreast of newly created regulations, such as AB32. Despite these improvements, California continues to face the nation's greatest air quality challenge. An Air Quality Engineer must work these challenges with Industry for efficient and feasible outcomes while keeping the mission to find and support alternatives or reduce hazards in order to protect the environment and its citizens. Ms. Patricia Menjivar will present her experiences as a Senior Air Quality Engineer.
Location: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Regional Earth System Modeling and Forecasting
Fri, Dec 07, 2007 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker: Dr. Yi Chao,
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CAAbstract: It was March 5, 1950, the first computerized weather forecast was issued using the world's first-ever electronic computer known as ENIAC (Electronic Numerical Integrator And Computer). It took just about 24 hours to make a 24-hour forecast. Today, a 7-day weather forecast takes only a few hours on today's supercomputers, and it becomes routine to check weather conditions before taking a vacation.In this talk, I will summarize the essential elements of a weather forecasting system. I will then review the current research and progress to apply the weather forecast technology in forecasting other Earth system components such as hurricane, ocean and climate. Our recent experiences in developing a forecasting system for the southern California coastal ocean will be described. The needs to refine these forecast systems ( e.g., increase the spatial resolutions from kilometers to meters down to the street level for air quality forecasting) and the associated information technology and computational challenge will be discussed.About the speaker (http://science.jpl.nasa.gov/people/Chao/)
Dr. Yi Chao received his Ph.D. in 1990 from Princeton University in a joint graduate program with NOAA Geophysical Fluid Dynamics Laboratory. After two years' postdoc research at UCLA, he joined Jet Propulsion Laboratory, California Institute of Technology as a Research Scientist in 1993. He is now a Principal Scientist and the manager for the Climate, Oceans and Solid Earth Section within the science division. His research interests include satellite oceanography with a particular focus on coastal oceans, numerical modeling and data assimilation, interdisciplinary science of Earth system science, and climate variability and change.
Location: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Uncertain Elasto-Plasticity
Wed, Dec 12, 2007 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker: Dr. Boris Jeremic, Department of Civil and Environmental Engineering, University of California, Davis, jeremic@ucdavis.eduAbstract:
Behavior of realistic materials is inherently uncertain. Two main sources of
such behavior are (a) the constitutive level uncertainties and (b) the uncertain
spatial variability of material.Presented in this talk is the method for simulating uncertain elastic-plastic
behavior. On the constitutive level, an Euler-Lagrange form of
Fokker-Planck-Kolmogorov (FPK) equation is applied to the description of the
evolution of probability density function of stress response for (any) elastic
and/or elastic-plastic material model with random material properties. The FPK
approach does not suffer from the "closure problem" associated with perturbation
methods nor does it require repetitive use of deterministic elastic-plastic
simulations as associated with Monte Carlo technique. Furthermore, the FPK
approach transforms the nonlinear stochastic constitutive ordinary differential
equation into linear deterministic partial differential equation, which, even if
not amenable to analytical solution, greatly simplifies the numerical solution
process. On the finite element level, spatial variability of material properties
is modeled and simulated using Karhunen-Loeve expansions of input random fields
in eigen-modes of their covariance function and polynomial chaos expansion with
Galerkin method to represent the solution random field.Number of examples will be presented, illustrating methodology and main results,
some of which are quite surprising and can be seen, at first glance as
counter-intuitive.Location: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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An Adaptive Cut-Cell Method for Environmental Fluid Mechanics
Thu, Dec 13, 2007 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:
Dr. Michael F. Barad, P.E.,
Environmental Fluid Mechanics Laboratory Department of Civil and Environmental Engineering, Stanford University, barad@stanford.edu Abstract:
I will present our block-structured adaptive mesh refinement (AMR) computational fluid dynamics model and its application to the study of highly nonlinear multiscale environmen¬tal flows. AMR allows researchers to "zoom in" on important flow features by dynamically tracking them with recursively nested finer grids. For example, this permits the accurate multiscale simulation of oceanic internal gravity waves, including generation at the meter scale, propagation and interaction over tens of kilometers, and sub-meter scale shear insta¬bility induced decay, all in the same calculation. The method is capable of simulating a wide range of flows in environmental fluid mechanics, including flows in lakes, rivers, wetlands, and the coastal ocean. The method is also capable of studying flows in bioreactors and other complex fluid systems, potential avenues for fruitful interdisciplinary collaborations.
The model is based on the solution of the variable density, incompressible, Navier-Stokes equations in two or three dimensions, including air/water and fluid/solid interfaces and the transport of scalars. It is composed of a second-order accurate, finite-volume projection method, which includes a slope limited Godunov discretization of the advective terms. We discretize irregular domains as a collection of (cut-cell) control volumes formed by the intersection of the domain with Cartesian grid cells. The control volumes naturally fit within parallelizable block data structures, and permit dynamic AMR coarsening and refinement of arbitrarily complex domains as a simulation progresses. This methodology is combined with finite-volume AMR discretizations based on two-way flux matching at refinement boundaries to obtain a conservative method that is second-order accurate in solution error.
Location: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Internationalizing the Engineering Curriculum
Fri, Dec 14, 2007 @ 11:00 AM - 12:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker:
Larry Shuman,
Senior Associate Dean and Professor of Industrial Engineering,
School of Engineering,
University of PittsburghAbstract:
Three years ago, Tom Friedman proclaimed that the "World is Flat." In doing this, Friedman delineated ten "flatteners" that converged around 2000 to both level the playing field for the design of products and services, and bring three billion new players onto the scene. Friedman, among others, emphatically proposes that it is now essential for U.S. engineering students to not only become more innovative, but equally important, learn to work collaboratively with colleagues across the globe. We have taken this message to heart and are creating innovative courses and programs to internationalize engineering education.We have done this in two ways. First by creating a series of innovative, short-term courses, and second, through a focus on sustainability, we have been able to leverage a growing relationship with a Brazilian partner to not only integrate more extensive international experiences into research and education, but to also do this at both the graduate and undergraduate levels. Further, we have been able to obtain funding to do much of this. Both ways will be addressed; current achievements and future plans will be presented, and challenges will be identified and discussed.Relative to the former, we have built upon a very successful study abroad experience for rising engineering and business students that combines coursework with a two week study visit focusing on manufacturing in an international setting. Using variations of this model we have developed upper level international courses that combine study at Pitt with international field visits. Three will be described: INNOVATE (ENGR 1600) that focuses on globalization and is taught simultaneously at Pitt, Rice and Tulsa using closed circuit TV to share lectures and bring students together. During the spring break, everyone plus other students and faculty from the US and India, Japan, Singapore and China participate in the INNOVATE symposium. This year's symposium will focus on Singapore and Vietnam. EMPOWER (ENGR 1620) focuses on the development of sustainable energy in Brazil. After a preparatory series of lectures students from Pitt and other US universities visit various sites in Brazil including the University of Campinas (UNICAMP). Product Realization for Global Economies (ENGR 1610) also brings together engineering and business students to develop a product (through prototype) for Brazilians living in public housing. Students travel to Brazil during the spring break; this year they will be joined by UNICAMP students as part of a course within a course. The latter effort has been headed by our Mascaro Sustainability Initiative (MSI) whose initial focus was on sustainable water usage and green building, but has recently expanded to include other sustainability problems. MSI has enabled us to build integrated educational and research programs in sustainability with a solid international component. Funding has been received from the National Science Foundation's Integrative Graduate Education and Research Traineeship (IGERT), International Research Experiences for Students (IRES), and REU programs; the US Department of Education's Graduate Assistance in Areas of National Need (GAANN) and FIPSE-CAPES programs; and the National Collegiate Inventors and Innovators Alliances (NCIIA) as well as private foundations. The interdisciplinary initiative involves faculty and students from across the University as well as international partners.
Location: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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ENE Oral Defense
Tue, Dec 18, 2007 @ 02:00 PM - 04:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Ultra Clean Fuels via UAOD Process with
Room Temperature Ionic Liquid and Solid Catalyst PolishingShun Sheng Cheng
KAP 209, 2007/12/20, 2-4 pmAbstractLimitation of 15 ppm has been considered for the content of sulfur in the diesel fuel due to the sulfur regulation by the EPA. However, ultra low sulfur diesel (ULSD) fuel has not been produced sufficiently by the current desulfurization technology.
In this study, a new desulfurization technology has been development, this include modified ultrasound assisted oxidative desulfurization (UAOD) process and fluidized bed reactor (FBR), which has been considered as one of the innovative schemes related to the desulfurization. In this respect, ionic liquid, oxidant, phase transfer catalysis, stirring, sonication, and acid catalyst have been combined in the modified UAOD process specifically. Thus, mild conditions have also provided high desulfurization efficiency.
During the study, proper oxidant, catalyst, as well as, ionic liquid was utilized during the demonstration under the modified UAOD process, specifically for model sulfur compounds. It has been observed that duration of three hours has been enough for desulfurize 99.9% of various type of model sulfur compound.
Various levels of sulfur content are contained, and can be observed in diesel fuels. Valley Oil, JP-5, and Treated Valley Oil are some of the levels. In this regard, 99.9% removal efficiency in the sulfur reduction can be demonstrated by the solvent extraction, as well as, solid adsorption, which has been followed by the modified UAOD process. Moreover, recycling can be done to the ionic liquid and acid catalyst, which is usually contained in the spent aqueous phase. Interestingly, high efficiency, as well as, high selectivity can be exhibited by the same.
In the pilot study, treatment tank, a pipeline system, as well as, high shear mixer has been created for the development of practical application of a batch-type continuous flow system. During these developments, appropriate time and mild conditions were given during the operations. The results show 99.9% of desulfurization efficiency can be achieve by the process. Moreover, utilization of ionic liquid and acid catalyst had been done at a less extent by the pilot study, as compared to the batch study.
FBR has been used to pass the oxidized organic compounds that have came out from the batch-type continuous flow system. Moreover, acidic alumina can adsorb almost 99.9% of oxidized sulfur, as indicated by the results. Additionally, recycling has also not affect the adsorption capacity of adsorbent.
It has been shown by the results of this dissertation that sulfur removal from the diesel fuels can be done effectively by the employment of modified UAOD process and FBR. In addition, new environmental standards can be met easily by the production of ULSD fuel by the utilization of appropriate design, as well as, chemicals during the process.
Location: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes