Student Abstracts: Environmental Science at LBNL

The DeltaQ Project: Quantifying Duct Leakage. BRIAN CARROLL (The University of Texas at Austin, Austin, TX 78704) DARRYL DICKERHOFF (Ernest Orlando Lawrence Berkley National Laboratory, Berkley, CA 94720) .
Existing HVAC duct systems in residential buildings are currently only 50 - 75% efficient due to air leakage to the outside environment. The recent mismatch of energy supply and demand has created an insurgence to increase the efficiency of such systems. The DeltaQ test measures the change in airflow through duct leaks (holes, cracks, poor construction) as the pressure across the leaks is varied in a controlled manner. With the HVAC system off, the house is pressurized using an apparatus called a Blower Door. Pressure transducers are placed at the inlet of the fan so that the pressure drop across the device can be measured. The fan is calibrated to produce a particular airflow rate for a given pressure drop. The fan speed is varied using computer software and pressure/flow data points are recorded. The test is then repeated with the HVAC system on. Analytical methods are then employed to curve fit the data with the least possible error. The resulting equation will determine the zero pressure point, which corresponds to the airflow out of the system's ductwork into the outside environment. My work focused on the precision of the test. My objective was to determine the repeatability and accuracy of DeltaQ test method. This was accomplished by installing various known leaks on an existing system located at an on-site testing facility. Numerous tests were performed and the results were compared to the expected leakage values. Results showed the test to be highly repeatable and accuracy was generally within 10% of the known value. The test has recently been proposed as a new ASTM standard for duct leakage measurements.

Cleanroom Energy Benchmarking. ZHONGNING CHEN (Cosumnes River College, Sacramento, CA 95823) TENGFANG (TIM) XU (Ernest Orlando Lawrence Berkley National Laboratory, Berkley, CA 94720) .
Cleanrooms are used in a wide range of industries, universities, and government facilities nowadays. Electronics and biotechnology industries which are important to the economy of California are heavily dependent upon energy-intensive cleanroom environments for their research and manufacturing. Energy use for environmental systems in these cleanrooms is high, as is the energy use for processes within cleanrooms. Pacific Gas and Electric Company (PG&E) and Lawrence Berkeley National Laboratory (LBNL) have been collecting energy use benchmarking data for energy intensive cleanroom facilities. The purpose is to provide useful energy metrics and measured data to building operators to enable them to assess their building systems performance. Meanwhile best practice information is expected to emerge which will provide awareness of the opportunities for continual improvement. Once data is collected, it is entered into a database for further evaluation and analysis. My summer research project mainly focuses on evaluation and analysis of the benchmarking data, which includes: 1) evaluate the completeness and accuracy of the benchmarking data; 2) improve the integrity of the benchmarking database; 3) conduct analysis on energy performance of environmental systems by generating charts for major metrics; 4) automate mass data analysis by using Microsoft Visual Basic; 5) document work progress & suggestions for further data analysis. I appreciate DOE, LBNL, & CSEE giving me this invaluable opportunity to study in such a world famous laboratory, and last but not least, my mentor Tim Xu for nurturing me not only how to be a good researcher, but also how to be a useful human being.

Salt-Balance in California's San Joaquin Valley. DAVID FOLLETTE (Princeton University, Princeton, NJ 08544) NIGEL QUINN (Ernest Orlando Lawrence Berkley National Laboratory, Berkley, CA 94720) .
The San Joaquin Valley is known for its fertile soil and highly productive farmland. However, with little rainfall, much of the agriculture is supported by groundwater pumping and federal and state surface water deliveries. Although the water from the Sierra Nevada snowmelt carries relatively little salt, large volumes of water use, coupled with little drainage outflow, create a serious salt balance problem. As salt accumulates in the soil, it becomes less fertile, crop yields decrease, and eventually the land is no longer economic to use. We approached the problem with a two-part solution. First, we set up and upgraded water quality monitoring stations on some of the smaller tributaries of the San Joaquin River. With a number of sensors at each site, water and salt flows are calculated. With this data, it will be easier to discriminate between the saline water sources, and work to minimize those discharges. Some of these sites required the design and construction of broad-crested weirs to act as water measurement control structures. Second, the stations were set up with modems and telephone connections for remote access to the data. In turn, with a computer and a modem, I set up a real-time system that automatically gathers data from each of the individual remote stations, creates graphs, and posts the data to the Internet. Agricultural users, bound to monthly load targets, can now monitor their discharges in real-time and ensure that they meet environmental standards. As this project continues to gather data, the salt-balance problem will be better understood and more easily solved.

In-situ X-ray Absorption Spectroscopy on Mn-Oxide based Lithium Battery Electrodes. ALISON FOWLKS (The University of Michigan, Ann Arbor, MI 48104) ARTUR BRAUN (Ernest Orlando Lawrence Berkley National Laboratory, Berkley, CA 94720) .
In-situ X-ray Absorption Spectroscopy was performed to investigate structural changes in Lithium Manganese Oxide, a lithium battery electrode material during electrochemical lithiation. Various spectroscopy techniques, such as XANES and EXAFS, were employed to monitor the changes in the electronic and crystallographic structure during the deep discharge process. XANES was used to quantitatively study the chemical shift of the spectra and to determine the average manganese oxidation state before and after discharge. EXAFS data provided such information as the inter-atomic distances and coordination numbers. Analysis of the EXAFS spectra showed the occurrence of a crystal phase transition from a cubic lattice to one of lower symmetry.

A Transition from Tango to Java. MONG KON MO (Fresno City College, Fresno, CA 93741) JONATHAN KOOMEY (Ernest Orlando Lawrence Berkley National Laboratory, Berkley, CA 94720) .
The End-Use Forecasting Group has developed a number of web applications (i.e. Home Energy Saver and Home Improvement Tool) using Tango. However, the group came to a decision that they wanted to port their Tango applications to Java for deployment on a Java Application Server because of the Java platform's increased stability, portability, and performance. Since the group does not have any Java programmers, they are consulting a private contractor, who will develop the Java applications. As an intermediate step in the transition from Tango to Java, a development Java Application Server (Orion) was setup and a connection between Orion and the group's Oracle database was verified with a sample Java 2 Enterprise Edition (J2EE) compliant application. As the Java applications are developed by the private contractor, the development server can be used to verify that the applications are functioning properly before being deployed on a production server.

Physiological and Kinetic Characterization of Octane-Degrading Bacteria. NICOLE PORTLEY (Boston College, Chestnut Hill, MA 02467) WILLIAM T. STRINGFELLOW (Ernest Orlando Lawrence Berkley National Laboratory, Berkley, CA 94720) .
Several bacteria capable of degrading n-alkanes have been isolated. These bacteria were grown in mixed cultures derived from enrichments of Mission Valley, California, soil. Several strains can use octane as a carbon source. Studies have focused on the physiology of these octane-degrading bacteria. Growth curve analysis allowed for differentiation between bacteria types, because log phase growth rates are unique for each strain. Respirometry analysis measured oxygen uptake by cells, which directly correlates with octane metabolism. Kinetic constants were measured for each organism, including the Ks (maximum growth rate) and Vmax (maximum enzyme activity under saturated conditions). Respirometry results demonstrated differences in efficiency among the enzymes, and this variance may indicate the presence of diverse enzymatic pathways. This research will be integrated with genetic analyses (16S rDNA gene and alkB gene) and Fatty Acid Methyl Ester analyses in order to identify and characterize these bacteria. These bacteria are being developed for use in industrial chemical production.

The Effects of Land Use on Midsummer Soil Respiration in Selected Crop Groups of the Southern Great Plains. NICOLE STALEY (Modesto Junior College, Modesto, CA 95350) MARC FISCHER (Ernest Orlando Lawrence Berkley National Laboratory, Berkley, CA 94720) .
Land use and management practices have significant impacts on the cycles of carbon in managed ecosystems. In order to understand and predict the effects of current and future land use I measured the soil respiration in plots that represent dominant land use types for the Southern Great Plains. I used an infared gas analyzer (Li-Cor 6400), thermocouples, and soil moisture sensors. I used a simple respiration model in which, soil respiration is dependent on the soil temperature, soil organic matter, root biomass, and moisture content of the soil. The laboratory tests confirmed that there is a temperature and moisture dependence. The field measurements showed that at this time of year the lack of soil moisture limits respiration to constant low levels, the temperature has less effect, and plant matter (AGB-above ground biomass) increases the respiration level.

Genetic Regulation of Selenium Detoxification in Bacillus subtilis. GENEVIEVE WALDEN (Fresno City College, Fresno, CA 93722) DR. TERRANCE LEIGHTON (Ernest Orlando Lawrence Berkley National Laboratory, Berkley, CA 94720) .
Selenium contamination is a major environmental problem in California, appearing as discharge from oil refineries in the Bay Area and as agricultural runoff in the Central Valley of California. The soil bacteria Bacillus subtilis has been shown to detoxify selenium by biotransforming the toxic, water soluble selenite to the insoluble, less toxic elemental selenium, and depositing the selenium between the cell wall and the plasma membrane. Since the exact mechanism of the detoxification pathway is still unclear, our project involved the use of sodium azide to stop the production of ATP during the detoxification process to see if the detoxification pathway was energy dependent. The main focus, however, was to knock out genes that had been identified through genome wide expression arrays as being overexpressed during detoxification. To characterize these genes, mutants were exposed to selenium stress in physiology experiments. At certain time points, samples were taken to assess cell viability counts and selenium detoxification.