SUNMONTUEWEDTHUFRISAT
Conferences, Lectures, & Seminars
Events for January
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The Sun Shines on Water and Atmospheric Aerosols
Wed, Jan 13, 2010 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Angela-Guiovana Rincon
W. M. Keck Laboratory, California Institute of TechnologyThe "free" energy carried by sunlight photons can drive accretion processes, such as photosynthesis, and degradative ones, such as the breakdown of air and water components. There is a growing interest in the development of new processes for water disinfection since the traditional processes, such as chlorination, generate toxic by-products. Sunlight is a promising alternative for water disinfection and Photocatalytic treatments based on innocuous titanium dioxide (TiO2) as ck&sensitizer vastly improve the disinfection efficiency of conventional solar water treatment. Photoexcited TiO2 induces the formation of highly reactive species, such as hydroxyl radicals, which universally inactivate bacteria and degrade organic pollutants.Key parameters influencing process efficiency involve physicochemical, biological and engineering aspects which are illustrated by laboratory and field scale experiments on solar disinfection. The sensitivity of bacteria to solar disinfection, in the absence or presence of TiO2, depend on microorganism species, strain, growth stage, cultivation medium and initial bacterial load. Disinfection results are affected by plating media used for bacterial cultivation and counting. Physicochemical parameters and reactor design also influence the process. A residual disinfection effect in the dark after solar treatment could only be observed in the presence of TiO2. Compliance with disinfection system standards require establishing the duration of the irradiation period, or effective disinfection time (EDT), that achieves full (> 99%) disinfection under specific conditions. EDT is strongly dependent on light intensity.The Earth's radiative balance is largely controlled by scattering and absorption of incoming sunlight by tropospheric aerosols. Their optical properties in the e>300nm range are essentially determined by their chemically complex "black" and "brown" natural and anthropogenic organic fractions. This phenomenon has moved to the forefront of climate change discussions, particularly after the failure of the Copenhagen summit, because it may ultimately provide an emergency geoengineering tool to control global warming via sulfate aerosol seeding.Atmospheric aerosols are exposed half of the time to intense sunlight. The key role of sunlight in their transformations is presented here using model organic aerosol. Photolysis of aqueous pyruvic acid (a surrogate for aerosol v-dicarbonyls absorbing at e>300nm) generates mixtures of identifiable aliphatic polyfunctional oligomers that develop absorptions in the visible upon standing in the dark. These absorptions can be repeatedly bleached and retrieved without carbon loss or changes in their electrospray ionization mass spectra. These observations, in conjunction with the evidence of supramolecular interactions among components of the mixture, together the non-linearity of Beer's law plots at e>350nm strongly suggest that full speciation is insufficient and possibly unnecessary for understanding the optical properties of the organic aerosol.Further studies in the presence of ammonium bisulphate indicate that the optical absorptivity of tropospheric aerosol particles is not an intrinsic property but a function of time that will respond to changes in insolation, ambient temperature and relative humidity. These phenomena and the time scales are consistent with the daily cycles of aerosol scattering and absorption observed over Mexico City.
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Ubiquitous Multi-Scale Structural Health Monitoring and Energy Harvesting System using...
Thu, Jan 21, 2010 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
...Piezoelectric SensorsDr. Seunghee Park, Assistant Professor
Department of Civil and Environmental Engineering
Department of U-City Design Engineering
Sungkyunkwan University - 300 Cheoncheon-dong
Jangan-gu Suwon Gyeonggi 440-746
KOREAA ubiquitous multi-scale structural health monitoring (SHM) and energy harvesting system using piezoelectric sensors is introduced. Firstly, SHM techniques based on the active sensing of piezoelectric materials are presented, which are broadly classified into 1) structural damage detection using impedance measurements, and 2) structural damage detection using guided wave propagations.Secondly, an energy harvesting technique using a piezoelectric patch that can convert mechanical vibrations to the electrical energy is investigated. Finally, by integrating both SHM and energy harvesting techniques with ubiquitous sensor network (USN), a ubiquitous multi- scale structural damage diagnostic system using a self-powered piezoelectric sensor node that consists of a embedded microprocessor, a miniaturized impedance measuring chip, a radio frequency (RF) telemetry module and a energy harvesting module is completed. In the near future, real-time wireless structural damage diagnosis for in-service infrastructures will be realized, implying a self-contained ubiquitous sensing system.
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Samoan Tsunami: Observations on Coastal Resilience
Wed, Jan 27, 2010 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Lesley Ewing
Sr. Civil Engineer, California Coastal CommissionAs a leader in the civil engineering community on disaster and response, the American Society of Civil Engineers (ASCE) has sent engineering teams into the field following major events, such as the attack on the World Trade Center, Hurricanes Katrina, Rita and Ike, and the Indian Ocean tsunami. In response to the 29 September 2009 Samoan Region Tsunami ASCE sent a small volunteer team of engineers to American Samoa and Samoa with the purpose of investigating the performance of coastal engineering structures, natural coastal systems, infrastructure and buildings. The ASCE team collaborated with a team of researchers from the Earthquake Engineering Research Institute and several Samoan engineers. A report of the field investigation and a technical note on structural performance are in preparation. Lesley Ewing, ASCE Team Leader, will present some of the initial observations from the Field Investigation concerning tsunami response, coastal change, structural response, lessons learned, what worked and what did not work.Lesley Ewing has worked as the California Coastal Commission's Civil Engineer for over 20 years during which time she has focused primarily on coastal issues, investigating shoreline change, and wave and storm damage along California's 1,067 miles of coast. Her work responsibilities include technical review of shoreline armoring projects, beach protection and restoration and new development along the coast. Her first Commission project was to report on the possible consequences from rising sea level to the California Coast and this has remained an important aspect throughout her current career. Prior to the CA Coastal Commission, she worked for the Rural Electrification Administration, Energy and Environmental Analysis, the Natural Resources Defense Council, and R.W. Beck and Associates.She is on the Senior Advisory Group for both California Ocean Observing Systems, technical advisor for USC's Sea Grant Program, technical reviewer for ASCE's International Conference on Coastal Engineering, past president and current director of California Shore & Beach Preservation Association, Director of the Coasts, Oceans, Ports and Rivers Institute of the ASCE, and has been on the organizing committee of several international coastal conferences, most recently ASCE's Solutions to Coastal Disasters. She is the recipient of the ASBPA Morrough P. O'Brien Award and the Coastal Zone Foundation's Coastal Zone Management Award.Ms. Ewing received a Sc.B. in civil engineering from Brown University, a M.R.P. in Regional Planning from the University of Massachusetts, Amherst, and M. Eng. in Coastal Engineering from the University of California, Berkeley. She is a licensed engineer in California and Virginia.
Audiences: Everyone Is Invited
Contact: Evangeline Reyes