Ronald P. Koopman

A handheld real time thermal cycler for bacterial pathogen detection.

The handheld advanced nucleic acid analyzer (HANAA) is a portable real time thermal cycler unit that weighs under 1 kg and uses silicon and platinum-based thermalcycler units to conduct rapid heating and cooling of plastic reaction tubes. Two light emitting diodes (LED) provide greater than 1 mW of electrical power at wavelengths of 490 nm (blue) and 525 nm (green), allowing detection of the dyes FAM and JOE/TAMRA. Results are displayed in real time as bar graphs, and up to three, 4-sample assays can be run on the charge of the 12 V portable battery pack. The HANAA was evaluated for detection of defined Escherichia coli strains, and wild-type colonies isolated from stream water, using PCR for the lac Z and Tir genes. PCR reactions using SYBR Green dye allowed detection of E. coli ATCC 11775 and E. coli O157:H7 cells in under 30 min of assay time; however, background fluorescence associated with dye binding to nonspecific PCR products was present. DNA extracted from three isolates of Bacillus anthracis Ames, linked to a bioterrorism incident in Washington DC in October 2001, were also successfully tested on the HANAA using primers for the vrrA and capA genes. Positive results were observed at 32 and 22 min of assay time, respectively. A TaqMan probe specific to the aroQ gene of Erwinia herbicola was tested on the HANAA and when 500 cells were used as template, positive results were observed after only 7 min of assay time. Background fluorescence associated with the use of the probe was negligible. The HANAA is unique in offering real time PCR in a handheld format suitable for field use; a commercial version of the instrument, offering six reaction chambers, is available as of Fall 2002.

Analysis of Burro series 40-m3 lng spill experiments

The U.S. Department of Energy sponsored a series of nine field experiments (Burro series) conducted jointly in 1980 by the Naval Weapons Center, China Lake, California, and the Lawrence Livermore National Laboratory to determine the transport and dispersion of vapor from spills of liquefied natural gas (LNG) on water. The spill volume ranged from 24 to 39 m3, the spill rate from 11.3 to 18.4 m3/min, the wind speed from 1.8 to 9.1 m/s, and the atmospheric stability from unstable to slightly stable. An extensive array of instrumentation was deployed both upwind and downwind of the spill pond. Wind speed and direction, gas concentration, temperature, humidity, and heat flux from the ground were measured at different distances from the spill point and at different elevations relative to ground level. The wind and gas-concentration data were analyzed to further define the fluid dynamic and thermodynamic processes associated with the dispersion of the gas cloud. Data pertaining to differential boiling of LNG and observed rapid phase-transition explosions were also analyzed. The principal conclusions are summarized as follows: The turbulent processes in the lower atmospheric boundary layer dominated the transport and dispersion of gas for all experiments except Burro 8. Burro 8 was conducted under very low wind-speed conditions, and the gravity flow of the cold gas displaced the atmospheric flow, causing the wind speed within the cloud to drop essentially to zero. This has profound implications for hazard prediction from large accidental spills. High-frequency (3–5 Hz) gas-concentration measurements indicate that peak concentrations within the flammable limits are common with 10-s-average concentrations above 1%. This implies a larger flammable extent than averaged data or calculations would indicate. Differential boiloff of LNG was observed with resultant enrichment of ethane and propane in the cloud at later times. This ethane-enriched region propagates downwind and represents an additional hazard since it is more easily detonated than the methane-rich region. Energetic rapid phase transition (RPT) explosions, though not expected, did occur under at least two different circumstances during the Burro 6 and 9 tests. These explosions were large enough to damage the facility and raise questions about the coupling of the RPT-produced shock wave into the ethane-rich region of the cloud.

A review of recent field tests and mathematical modelling of atmospheric dispersion of large spills of Denser-than-air gases

Large-scale spills of hazardous materials often produce gas clouds which are denser than air. The dominant physical processes which occur during dense-gas dispersion are very different from those recognized for trace gas releases in the atmosphere. Most important among these processes are stable stratification and gravity flow. Dense-gas flows displace the ambient atmospheric flow and modify ambient turbulent mixing. Thermodynamic and chemical reactions can also contribute to dense-gas effects. Some materials flash to aerosol and vapor when released and the aerosol can remain airborne, evaporating as it moves downwind, causing the cloud to remain cold and dense for long distances downwind. Dense-gas dispersion models, which include phase change and terrain effects have been developed and are capable of simulating many possible accidental releases. A number of large-scale field tests with hazardous materials such as liquefied natural gas (LNG), ammonia (NH3), hydrofluoric acid(HF) and nitrogen tetroxide(N2O4) have been performed and used to evaluate models. The tests have shown that gas concentrations up to ten times higher than those predicted by trace gas models can occur due to aerosols and other dense-gas effects. A methodology for model evaluation has been developed which is based on the important physical characteristics of dense-gas releases.

A Refuelable Zinc/Air Battery for Fleet Electric Vehicle Propulsion

We report the development and on-vehicle testing of an engineering prototype zinc/air battery. The battery is refueled by periodic exchange of spent electrolyte for zinc particles entrained in fresh electrolyte. The technology is intended to provide a capability for nearly continuous vehicle operation, using the fleet s home base for 10 minute refuelings and zinc recycling instead of commercial infrastructure. In the battery, the zinc fuel particles are stored in hoppers, from which they are gravity fed into individual cells and completely consumed during discharge. A six-celled (7V) engineering prototype battery was combined with a 6 V lead/acid battery to form a parallel hybrid unit, which was tested in series with the 216 V battery of an electric shuttle bus over a 75 mile circuit. The battery has an energy density of 140 Wh/kg and a mass density of 1.5 kg/L. Cost, energy efficiency, and alternative hybrid configurations are discussed.

Handheld advanced nucleic acid analyzer

There is a growing need for portable, lightweight, battery operated instruments capable of detecting and identifying bio-warfare and bio-terrorism agents in the field. To address this need, we have developed a handheld PCR instrument. LLNLs advanced thermal cycling technology and expertise with portable, field tested biological instrumentation, combined with the development of real-time, fluorescence based PCR assays, has enabled the development of a very portable, versatile, power efficient PCR instrument with a simplified operating system designed for use by first responders. The heart of the instrument is the sample module, which incorporates the advanced silicon thermal cycler developed at LLNL.

Atmospheric dispersion of large scale spills

Large scale spills of volatile cryogenic or pressurized ambient temperature liquids often produce denser-than-air clouds which disperse in the atmosphere in a manner that is different than trace gases. These differences are due to density or gravity-induced effects such as turbulence damping from the stable density stratification, alteration of the ambient velocity field due to gravity flow, and the source momentum flux. Also important are thermodynamic effects such as aerosol formation and flash vaporization upon release, evaporative cooling, or heat transfer from the ground modifying cloud buoyancy and turbulence. In addition, chemical reaction effects such as hydrolysis with atmospheric water vapor, polymerization, or decomposition which also affects cloud density and thermodynamics can be important. These effects are very important close to the release point but also can have dramatic effects on the cloud as it disperses downwind. Large scale tests involving releases of heavy gases have been conducted...

Results of 40-m3 LNG Spills onto Water

Lawrence Livermore National Laboratory (LLNL) is conducting safety research under the sponsorship of the U.S. Department of Energy (DOE) to determine the possible consequences of liquefied natural gas (LNG) spills. The LLNL program includes both the collection of data from various size experiments and development of an ensemble of computer models to make predictions for conditions under which tests cannot be performed. In spills of 40 cubic metres (m3) of LNG onto water done at the Naval Weapons Center (NWC), China Lake, California in 1980 and 1981, data was collected on gas cloud dispersion and combustion and rapid phase transition (RPT) explosions. Analysis of the data from these tests, including comparisons between the predictions of various models and the data, are presented. The results suggest that largescale spills may be more hazardous than would have been predicted based on earlier small-scale tests. Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract number W-7405-ENG-48.