53 research outputs found
FLORIDA TOWER FOOTPRINT EXPERIMENTS
The Florida Footprint experiments were a series of field programs in which perfluorocarbon tracers were released in different configurations centered on a flux tower to generate a data set that can be used to test transport and dispersion models. These models are used to determine the sources of the CO{sub 2} that cause the fluxes measured at eddy covariance towers. Experiments were conducted in a managed slash pine forest, 10 km northeast of Gainesville, Florida, in 2002, 2004, and 2006 and in atmospheric conditions that ranged from well mixed, to very stable, including the transition period between convective conditions at midday to stable conditions after sun set. There were a total of 15 experiments. The characteristics of the PFTs, details of sampling and analysis methods, quality control measures, and analytical statistics including confidence limits are presented. Details of the field programs including tracer release rates, tracer source configurations, and configuration of the samplers are discussed. The result of this experiment is a high quality, well documented tracer and meteorological data set that can be used to improve and validate canopy dispersion models
Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7 fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale
Searches for electroweak neutralino and chargino production in channels with Higgs, Z, and W bosons in pp collisions at 8 TeV
Searches for supersymmetry (SUSY) are presented based on the electroweak pair production of neutralinos and charginos, leading to decay channels with Higgs, Z, and W bosons and undetected lightest SUSY particles (LSPs). The data sample corresponds to an integrated luminosity of about 19.5 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV collected in 2012 with the CMS detector at the LHC. The main emphasis is neutralino pair production in which each neutralino decays either to a Higgs boson (h) and an LSP or to a Z boson and an LSP, leading to hh, hZ, and ZZ states with missing transverse energy (E-T(miss)). A second aspect is chargino-neutralino pair production, leading to hW states with E-T(miss). The decays of a Higgs boson to a bottom-quark pair, to a photon pair, and to final states with leptons are considered in conjunction with hadronic and leptonic decay modes of the Z and W bosons. No evidence is found for supersymmetric particles, and 95% confidence level upper limits are evaluated for the respective pair production cross sections and for neutralino and chargino mass values
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DETECTION OF INTERSTATE LIQUIDS PIPELINE LEAKS: FEASIBILITY EVALUATION.
The approximately 200,000-mile fuel pipeline system in the U.S. operates at flow rates up to 2.5 x 10{sup 6}gallons per hour (GPH). Most commercial technologies only provide on-line leak detection at about 0.3% of flow rate, i.e., about 7,500 GPH or larger. Detection of leaks at about 1 GPH or so is desirable both from a regulatory and leak-prevention standpoint. Brookhaven's commercially-accepted perfluorocarbon tracer (PFT) technology for underground leak detection of utility industry dielectric fluids at leak rates less than 0.1 GPH, with new enhancements, will be able to cost-effectively detect fuel pipeline system leaks to about 1 GPH--3 orders-of-magnitude better than any on-line system. The magnitude of detected leaks would be calculable as well. Proposed mobile surveys (such as those used periodically in the gas pipeline industry) at about 110 to 120 miles per day would allow such small leaks to be detected at 10-ppb tagging levels (less than $1,500 of PFT for a 48-hour tag at the maximum transport rate) under worst-case meteorological dispersion conditions. Smaller leaks could be detected by proportionately larger tagging concentrations. Leaks would be pinpointed by subsequent conventional barholing and vapor analyses. There are no health nor safety issues associated with the use of the proposed technological approach nor any consequential environmental impacts associated with the proposed magnitudes of PFT tagging
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Rate processes for iodine removal and hypoiodous acid formation in the presence of chemically reactive containment sprays
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Feasibility of perfluorocarbon tracers (PFTs) in atmospheric source-receptor experiments
A brief description of the perfluorocarbon tracer (PFT) system, which includes the tracers and the release equipment, the air samplers and the analyzers, is presented along with details on the research needs to provide a viable system for MATEX-scenario experiments. The present family of 2 viable PFTs needs to be increased to 5 to 6. Given the present precision of the analysis system, a one year long tracer experiment consisting of 4 hour releases every 60 hours from 5 different sites would require nearly 150 metric tons of PFTs at a cost of 13,000,000. A model is presented to demonstrate the feasibility of tracer material balances. Assessment of earlier long-range tracer experiments indicates the need for possibly 400 ground sampling sites requiring 14 million worth of samplers for a one-year tracer experiment. As many as six aircraft would be needed to conduct airborne model validation and material balance studies for each tracer plume
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Evaluation of an airborne gas chromatograph for long distance meteorological tracing
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Variables effecting ozone treatment of physical-chemical effluent
The treatment of raw sewage from an on-site apartment area was investigated in a series of laboratory experiments in which changes in turbidity, pH, total organic carbon, chemical oxygen demand, and, in some cases, biochemical oxygen demands were determined. Raw sewage, but mainly the effluent following physical-chemical treatment, was examined for improvement in discharge quality by ozone treatment in combination with oxygen sparging, ionizing gamma radiation from /sup 60/Co heating, acidifying, and several other variables. The average composition of the raw sewage was a TOC of 125 ppM (range from 65 to 240), COD of 190 ppM (range from 85 to 475), turbidity of 145 J. U. (range from 60 to 350), and pH of 7.3 (range from 6.5 to 8.4). Physical chemical treatment usually consisted of the addition of CaO (to pH 11) and FeCl/sub 3/ as a coagulant aid in an inclined tube followed by course filtration; typical treatment time was 15 minutes giving an average reduction in TOC and COD of 40 to 60%. Subsequent treatment was usually performed with 200 cm/sup 3/ samples of the effluent in fine and course fritted bubblers. The combination of radiation plus ozone gave the largest reduction of TOC and COD. In one experiment, 15 minutes of treatment followed by 30 minutes of irradiation and ozonation reduced the raw sewage TOC from 95 to 14 ppM carbon and COD from 150 to 6 ppM oxygen. (auth
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Brookhaven air infiltration measurement system (BNL/AIMS) description and application
A unique capability to measure part-per-quadrillion concentrations of a family of perfluorocarbon tracers (PFTs) is presented. Together with our unique PFT source and passive sampler, measurement of average air exchange and infiltration rate can be determined for periods as short as 12 hours. A more expensive programmable sampler can provide information on a frequency of as little as once per minute for each of its 23 sampling tubes. The principal of AIMS is based on the applicable steady-state assumption that the average concentration (e.g., in pL/L) of a tracer vapor in a chamber (i.e., a building or room) is equal to the emission rate of the tracer source (e.g., in pL/min) divided by the air leakage or infiltration rate (e.g., in L/min). Knowing the source rate and measuring the average concentration then provides a means to calculate the air leakage rate. Extending this technique to a multichamber concept, in which a different type of PFT source is deployed in each chamber of a building, allows the calculation of not only the infiltration rates in each chamber but also the air exchange rates between chambers as well. Since both the PFT source and the passive sampler, a miniature Capillary Adsorption Tube Sampler (CATS), are about the size of a cigarette, inexpensive, and reusable, the BNL/AIMS is a very cost-effective means (if not the only means) for determining these air exchange rates
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