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Sample records for gas chromatography-electron impact

  1. Validated toxicological determination of 30 drugs of abuse as optimized derivatives in oral fluid by long column fast gas chromatography/electron impact mass spectrometry.

    PubMed

    Gunnar, Teemu; Ariniemi, Kari; Lillsunde, Pirjo

    2005-06-01

    An analytical procedure was developed for the simultaneous sensitive identification, screening and quantitation of 30 drugs of abuse using 250 microl of human oral fluid. The method employs sequential mixed-mode solid-phase extraction (SPE), optimized derivative formation and long-column fast gas chromatography/electron impact mass spectrometry (GC/EI-MS). After sequential SPE elution, the most sensitive and stable derivatives were formed by taking careful account of the characteristics of the active functional groups and possible steric hindrances affecting derivatization chemistry. Amphetamine-type stimulant drugs were acylated with heptafluorobutyric anhydride, benzodiazepines and Delta(9)-tetrahydrocannabinol were silylated with N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide and benzoylecgonine, codeine, ethylmorphine, 6-monoacetylmorphine, morphine, pholcodine, buprenorphine and norbuprenorphine with N-methyl-N-(trimethylsilyl)trifluoroacetamide. In addition, the following analytes were included: methadone, cocaine, alprazolam, midazolam, fentanyl and zolpidem. In GC separation, fast temperature ramping and high carrier gas flow-rate combined with long 30 m columns of i.d. 0.32 mm offered a reduction in analysis time and sharp peak shapes while still maintaining sufficient resolution and high sample capacity. Validated parameters including selectivity, linearity, accuracy, intra- and inter-day precision, extraction efficiency and limit of quantitation were all within required limits. In contrast to previously published methods, this single procedure is suitable for the simultaneous toxicological determination of the most common illicit drugs and benzodiazepines, and also zolpidem, in a small amount of oral fluid. PMID:15806585

  2. DETERMINATION OF ACRYLAMIDE IN RAT SERUM AND SCIATIC NERVE BY GAS CHROMATOGRAPHY-ELECTRON-CAPTURE DETECTION

    EPA Science Inventory

    A modified method for the derivatization and analysis of acrylamide as 2-bromopropenamide by gas chromatography/electron capture detection was validated in serum and sciatic nerve from rats. he method was accurate and precise over the concentration range of 2240 to 74700 ppm (w/v...

  3. Rapid direct analysis to discriminate geographic origin of extra virgin olive oils by flash gas chromatography electronic nose and chemometrics.

    PubMed

    Melucci, Dora; Bendini, Alessandra; Tesini, Federica; Barbieri, Sara; Zappi, Alessandro; Vichi, Stefania; Conte, Lanfranco; Gallina Toschi, Tullia

    2016-08-01

    At present, the geographical origin of extra virgin olive oils can be ensured by documented traceability, although chemical analysis may add information that is useful for possible confirmation. This preliminary study investigated the effectiveness of flash gas chromatography electronic nose and multivariate data analysis to perform rapid screening of commercial extra virgin olive oils characterized by a different geographical origin declared in the label. A comparison with solid phase micro extraction coupled to gas chromatography mass spectrometry was also performed. The new method is suitable to verify the geographic origin of extra virgin olive oils based on principal components analysis and discriminant analysis applied to the volatile profile of the headspace as a fingerprint. The selected variables were suitable in discriminating between "100% Italian" and "non-100% Italian" oils. Partial least squares discriminant analysis also allowed prediction of the degree of membership of unknown samples to the classes examined. PMID:26988501

  4. PARTICLE BEAM LIQUID CHROMATOGRAPHY-ELECTRON IMPACT MASS SPECTROMETRY OF DYES

    EPA Science Inventory

    A liquid chromatograph was interfaced with a triple quadrupole mass spectrometer by means of a particle beam-type interface. he system was used for the analysis and characterization by electron impact mass spectra of a series of commercial dyes. he pure dyes were separated from t...

  5. Determination of chlorobenzenes in water samples by solid-phase disk extraction and gas chromatography-electron capture detection.

    PubMed

    Hu, Hongmei; Guo, Yuanming; Sun, Xiumei; Chen, Xuechang; Zhang, Xiaoning; Liu, Qin; Xu, Chunxiu

    2014-01-01

    A simple, rapid, sensitive and high throughput method is described, based on solid-phase disk extraction (SPDE) and gas chromatography-electron capture detection, for the determination of chlorobenzens (CBs) in water samples. The proposed SPDE sample pretreatment method was initially optimized and the optimum experimental conditions were found to be as follows: 500 mL water sample (pH 2.5) extracted and enriched by an Empore 3-stn C18 (octadecyl) SPE disk at flow rate of 5 to 50 mL/min, eluted by 5 mL of acetone and 3 5 mL of methylene dichloride. The linearity of the method ranged from 0.02 to 0.4 g/L for dichlorobenzene isomers, 0.0022-0.044 g/L for trichlorobenzene isomers, 0.005-0.01 g/L for tetrachlorobenzene isomers and 0.00025 to 0.005 g/L for pentachlorobenzenes and hexachlorobenzenes, with correlation coefficients ranging between 0.9991 and 0.9999. The limits of detection were in the low ng/L level, ranging between 0.05 and 4 ng/L. The recoveries of spiked CBs with the external calibration method at different concentration levels in deionized/distilled water, tap water and sea water samples were 99-115, 91-106% and 96-110%, respectively, and with relative standard deviations of 4.5-7.6, 4.2-6.8 and 3.6-6.6% (n = 5), respectively. It is concluded that this method can successfully be applied for the determination of CBs in deionized/distilled water, tap water and sea water samples. PMID:23645828

  6. Analysis of butter fat triacylglycerols by supercritical fluid chromatography/electron impact mass spectrometry.

    PubMed

    Kallio, H; Laakso, P; Huopalahti, R; Linko, R R; Oksman, P

    1989-04-01

    Triacylglycerols (TAGs) from butter fat isolated by solvent extraction were analyzed by use of a capillary column supercritical fluid chromatograph (SFC) combined with a flame ionization detector or a double focusing mass spectrometer. The chromatographic separation was achieved by using a dimethyldiphenylpolysiloxane phase (DB-5) to bundle up the TAGs with the same carbon number. The ratio of TAGs with varying degree of unsaturation in each SFC peak was determined by using the selected ion monitoring of the molecular ions with electron impact mode. The discrimination between the fatty acids at the position sn-2 and positions sn-1/3 in a triacylglycerol molecule was demonstrated by monitoring the ions [M - RCO2CH2]+ from reference compounds. PMID:2719267

  7. Comparison and analysis of organochlorine pesticides and hexabromobiphenyls in environmental samples by gas chromatography-electron capture detector and gas chromatography-mass spectrometry.

    PubMed

    Liu, Yu; Fu, Xiaofang; Tao, Shu; Liu, Liang; Li, Wei; Meng, Bingjun

    2015-02-01

    Two analytical methods, gas chromatography-electron capture detector (GC-ECD) and gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS), were evaluated and compared for the measurement of persistent organic pollutants, specifically for 26 organochlorine pesticides and two hexabromobiphenyls, in atmospheric particulate matter and soil samples. The hypothesis tested was that the coelution of non-target compounds may lead to false positives when analyzed by GC-ECD, and that the overestimation associated with these false positives can be eliminated using GC-NCI-MS. The study showed that both methods had satisfactory linearity and reproducibility for the target compounds. Although the sensitivities of GC-ECD for most of the compounds investigated were higher than those observed with the GC-NCI-MS method, the matrices interference was obvious with GC-ECD. There was indeed an apparently high false-positive rate or overestimate when GC-ECD was used for environmental samples, implying that the GC-ECD method has been used with care and that GC-NCI-MS is generally superior for the analysis of trace amounts of these compounds in environmental samples. Based on these results, the sample extraction and cleanup procedures of the GC-NCI-MS method were optimized for achieving acceptable recoveries and less matrices interference. PMID:24872522

  8. Measurement of polychlorinated biphenyls in solid waste such as transformer insulation paper by supercritical fluid extraction and gas chromatography electron capture detection.

    PubMed

    Chikushi, Hiroaki; Fujii, Yuka; Toda, Kei

    2012-09-21

    In this work, a method for measuring polychlorinated biphenyls (PCBs) in contaminated solid waste was investigated. This waste includes paper that is used in electric transformers to insulate electric components. The PCBs in paper sample were extracted by supercritical fluid extraction and analyzed by gas chromatography-electron capture detection. The recoveries with this method (84-101%) were much higher than those with conventional water extraction (0.08-14%), and were comparable to those with conventional organic solvent extraction. Limit of detection was 0.0074 mg kg(-1) and measurable up to 2.5 mg kg(-1) for 0.5 g of paper sample. Data for real insulation paper by the proposed method agreed well with those by the conventional organic solvent extraction. Extraction from wood and concrete was also investigated and good performance was obtained as well as for paper samples. The supercritical fluid extraction is simpler, faster, and greener than conventional organic solvent extraction. PMID:22907045

  9. Solid phase extraction with silicon dioxide microsphere adsorbents in combination with gas chromatography-electron capture detection for the determination of DDT and its metabolites in water samples.

    PubMed

    Zhou, Qingxiang; Wu, Wei; Xie, Guohong

    2013-01-01

    The goal of the present study was to investigate the feasibility of silicon dioxide (SiO(2)) microspheres without special modification to enrich dichlorodiphenyltrichloroethane (DDT) and its main metabolites, p,p'-dichlorodiphenyl-2,2-dichloroethylene (p,p'-DDD) and p,p'-dichlorodiphenyldichloroethylene (DDE) in combination with gas chromatography-electron-capture detection. The experimental results indicated that an excellent linear relationship between the recoveries and the concentrations of DDT and its main metabolites was obtained in the range of 0.2-30 ng mL(-1) and the correlation coefficients were in the range of 99.96-99.99%. The detection limits based on the ratio of signal to the baseline noise (S/N = 3) were 2.2, 2.9, 3.8 and 4.1 ng L(-1) for p,p'-DDD, p,p'-DDT, o,p'-DDT, and p,p'-DDE, respectively. The precisions of the proposed method were all below 10% (n = 6). Four real water samples were utilized for validation of the proposed method, and satisfactory spiked recoveries in the range of 72.4-112.9% were achieved. These results demonstrated that the developed method was a simple, sensitive, and robust analytical method for the monitoring of pollutants in the environment. PMID:23356340

  10. Determination of acetanilide herbicides in cereal crops using accelerated solvent extraction, solid-phase extraction and gas chromatography-electron capture detector.

    PubMed

    Zhang, Yaping; Yang, Jun; Shi, Ronghua; Su, Qingde; Yao, Li; Li, Panpan

    2011-07-01

    A method was developed to determine eight acetanilide herbicides from cereal crops based on accelerated solvent extraction (ASE) and solid-phase extraction (SPE) followed by gas chromatography-electron capture detector (GC-ECD) analysis. During the ASE process, the effect of four parameters (temperature, static time, static cycles and solvent) on the extraction efficiency was considered and compared with shake-flask extraction method. After extraction with ASE, four SPE tubes (graphitic carbon black/primary secondary amine (GCB/PSA), GCB, Florisil and alumina-N) were assayed for comparison to obtain the best clean-up efficiency. The results show that GCB/PSA cartridge gave the best recoveries and cleanest chromatograms. The analytical process was validated by the analysis of spiked blank samples. Performance characteristics such as linearity, limit of detection (LOD), limit of quantitation (LOQ), precision and recovery were studied. At 0.05 mg/kg spiked level, recoveries and precision values for rice, wheat and maize were 82.3-115.8 and 1.1-13.6%, respectively. For all the herbicides, LOD and LOQ ranged from 0.8 to 1.7 μg/kg and from 2.4 to 5.3 μg/kg, respectively. The proposed analytical methodology was applied for the analysis of the targets in samples; only three herbicides, propyzamid, metolachlor and diflufenican, were detected in two samples. PMID:21656677

  11. [Analysis of organochlorine pesticides and pyrethroid pesticides in vegetables by gas chromatography-electron capture detection coupled with solid-phase extraction using multiwalled carbon nanotubes as adsorbent].

    PubMed

    Zhao, Haixiang; Jia, Yanxia; Ding, Mingyu; Sun, Dajiang; Zhao, Mengbin

    2011-05-01

    A multi-residue analytical method based on solid-phase extraction (SPE) with multiwalled carbon nanotubes (MWCNTs) as adsorbent was developed. The determination of 6 organochlorine pesticides and 7 pyrethroid pesticides in vegetables (including cucumber, cherry tomato, cabbage, lettuce, purple cabbage, leek, shallot and onion) was carried out by gas chromatography-electron capture detection (GC-ECD). The GC-ECD method used two columns (HP-50 and HP-1) and two ECD detectors. The HP-50 column was used for the analysis and the HP-1 column for validation. The clean-up conditions were optimized. The analytes were extracted by acetonitrile, and the extract was cleaned up by the MWCNTs SPE cartridge. The extract was re-dissolved by hexane, eluted with acetone-hexane (7:3, v/v) from the columns. The recoveries were over 70% for the 11 pesticides in the 13 pesticides. The results indicated that the MWCNTs SPE cartridge was efficient for 8 vegetable samples, because it reduced the contamination of the coloring materials to GC-ECD. The experimental results showed the MWCNTs SPE cartridge can adsorb the coloring materials and the eluant was nearly colorless. PMID:21847981

  12. Analysis of organophosphate flame retardants and plasticisers in water by isotope dilution gas chromatography-electron ionisation tandem mass spectrometry.

    PubMed

    Teo, Tiffany L L; McDonald, James A; Coleman, Heather M; Khan, Stuart J

    2015-10-01

    The widespread use of organophosphate flame retardants (PFRs) in commercial products have led to their increased presence in the environment. In this study, a rapid and reliable analytical method was developed for the analysis of five PFRs in water using gas chromatography tandem mass spectrometry (GC-MS/MS) with electron ionisation (EI) and a run time of 13 min. The PFRs investigated were tributyl phosphate (TBP), tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP), tris(1,3-dichloro-2-propyl) phosphate (TDCP) and triphenyl phosphate (TPP). Solid phase extraction (SPE) was undertaken to extract and concentrate target analytes from aqueous matrices. All water samples were extracted from a volume of 500 mL. Isotopically labelled compounds were used to account for analytical variability and for accurate quantification by isotope dilution. Method recoveries for all compounds were above 80% in all tested water samples. Method detection limits for all target analytes ranged from 0.3 to 24 ng/L in ultrapure water, tap water, seawater, surface water, secondary effluent and swimming pool water. Validation of this method confirmed satisfactory method stability with less than 1% coefficients of variation, verifying that this approach produced good reproducibility. PMID:26078137

  13. Evaluation of BDE-47 hydroxylation metabolic pathways based on a strong electron-withdrawing pentafluorobenzoyl derivatization gas chromatography/electron capture negative ionization quadrupole mass spectrometry.

    PubMed

    Zhai, Chao; Peng, Shunv; Yang, Limin; Wang, Qiuquan

    2014-07-15

    Understanding the metabolic pathways of polybrominated diphenyl ethers (PBDEs) is a key issue in the evaluation of their cytotoxicity after they enter the biota. In order to obtain more information concerning the metabolic pathways of PBDEs, we developed a strong electron-withdrawing pentafluorobenzoyl (PFBoyl) derivatization capillary gas chromatography/electron capture negative ionization quadrupole mass spectrometry (GC/ECNI-qMS). PFBoyl esterification greatly improves separation of the metabolites of PBDEs such as hydroxylated PBDEs (OH-PBDEs) and bromophenols (BPs) metabolites in rat liver microsomes (RLMs). On the other hand, the strong electron-withdrawing property of PFBoyl derivatized on OH-PBDEs and/or BPs makes cleavage of the ester bond on ECNI easier resulting in higher abundance of the structure-informative characteristic fragment ions at a high m/z region, which facilitate the identification of OH-PBDEs metabolites. Subsequent quantification can be performed by monitoring not only 79Br- (or 81Br-) but also their characteristic fragment ions, achieving more accurate isotope dilution quantification using GC/ECNI-qMS. These merits allow us to identify totally 12 metabolites of BDE-47, a typical example of PBDEs, in the RLMs in vitro incubation systems. In addition to the already known metabolites of BDE-47, one dihydroxylated 3,6-di-OH-BDE-47 and one dihydroxylated 3,5-di-OH-tetrabrominated dioxin were found. Moreover, the second hydroxylation took place on the same bromophenyl ring, where the first hydroxyl group was located, and was further confirmed via the identification of the dihydroxylated 2',6'-di-OH-BDE-28 of an asymmetric 2'-OH-BDE-28. This methodological development and its subsequent findings of the metabolic pathways of BDE-47 provided experimental evidence for understanding its dioxin-like behavior and endocrine disrupting risk. PMID:24925108

  14. Simultaneous determination of amitraz and its metabolite residue in food animal tissues by gas chromatography-electron capture detector and gas chromatography-mass spectrometry with accelerated solvent extraction.

    PubMed

    Yu, Huan; Tao, Yanfei; Le, Tao; Chen, Dongmei; Ishsan, Awais; Liu, Yu; Wang, Yulian; Yuan, Zonghui

    2010-07-01

    A new method has been developed for determination and confirmation of amitraz and its main metabolite, 2,4-dimethylaniline, in food animal tissues using gas chromatography-electron capture detector (GC-ECD) and gas chromatography-mass spectrometry detector (GC-MS). This method is based on a new extraction procedure using accelerated solvent extraction (ASE). It consists of an n-hexane/methanol extraction step, a cleaning-up step by BakerBond octadecyl C(18) silica bonded cartridge, hydrolysis and derivatization to 2,4-dimethyl-7-F-butyramide for GC-ECD analysis. For confirmation using GC-MS, hydrolysis and derivatization were not needed. Parameters for extraction pressure, temperature and cycle of ASE, clean-up, derivatization and analysis procedure have been optimized. Spike recoveries from 50 to 300 microg/kg levels were found to be between 72.4 and 101.3% with relative standard deviation less than 11.5% in GC-ECD, from 5 to 20 microg/kg levels were found to be between 77.4 and 107.1% with relative standard deviation less than 11.6% in GC-MS. The LOD and LOQ are 5 and 10 microg/kg, respectively, for these two analytes using GC-ECD. For GC-MS, LOD and LOQ were 2 and 5 microg/kg, respectively. The rapid and reliable method can be used for characterization and quantification of residues of amitraz and its main metabolite, 2,4-dimethylaniline, in liver and kidney samples of swine, sheep and bovine. PMID:20554255

  15. Studies of toxaphene in technical standard and extracts of background air samples (Point Petre, Ontario) using multidimensional gas chromatography-electron capture detection (MDGC-ECD).

    PubMed

    Shoeib, M; Brice, K A; Hoff, R M

    2000-01-01

    MDGC-ECD procedures have been used to provide insight into the compositional complexity of some of the specific peaks or clusters observed in the gas chromatographic analysis of a technical toxaphene standard, with reference to individual toxaphene congeners (Parlar # components) that are flow commercially available. These investigations have focussed initially upon those peaks and clusters recently identified (Shoeib. M., Brice, K.A., Hoff, R., 1999. Chemosphere 39, 849-871) as dominant constituents of background ambient air. Multiple electron-capturing components have been found to be present in all the species studied: the available individual toxaphene congeners have been matched against these components where possible. In similar fashion, the responses obtained in equivalent gas chromatographic elution windows from the analysis of typical processed air sample extracts have been investigated, with the results showing clear differences relative to the patterns found in the technical toxaphene standard. In most cases, the air sample shows reduced complexity with fewer components present in the cluster. Also, the presence of interfering responses (due to PCBs and other organochlorines) is quite apparent and significant, showing that major problems and errors could arise when using single-column GC-ECD procedures for quantitation of toxaphene in environmental samples. The presence of certain of the Parlar species in the air samples has been confirmed and in most cases these represent the dominant toxaphene component found in the targeted cluster. Furthermore, the persistence of certain congeners in the atmospheric samples appears to be strongly dependent upon chemical structure, since the congeners in question possess an alternating exo-endo chlorine substitution pattern around the six-membered ring in the bornane skeleton. Such persistence is probably the result of lower metabolization of toxaphene residues in soils, water and sediments leading to a similar pattern in the atmosphere following volatilization. PMID:10665433

  16. Use of solid-phase microextraction/gas chromatography-electron capture detection for the determination of energetic chemicals in marine samples.

    PubMed

    Monteil-Rivera, Fanny; Beaulieu, Chantale; Hawari, Jalal

    2005-02-25

    Gas chromatography with electron capture detection (GC-ECD) is a highly explosive-sensitive analytical technique. However, its application to the analysis of sediment extracts is hampered by the presence of numerous endogenous interferences. In the present study, solid-phase microextraction (SPME) was used both as a purification technique for sediment extracts and as an extraction technique for water samples prior to analysis by GC-ECD. SPME/GC-ECD coupling was optimized and applied to the trace analysis of nine explosives including nitroaromatics and RDX in real seawater and marine sediment samples. Addition of a high concentration of salt (30%, w/v) in the aqueous medium and use of a carbowax/divinylbenzene (CW/DVB) coating led to optimal extraction efficiencies. Method detection limits (MDLs) ranged from 0.05 to 0.81 microg/L in water and from 1 to 9 microg/kg in dry sediment. Except for RDX, spike recoveries in seawater were satisfactory (89-147%) when samples were fortified at 2 microg/L of each analyte. Spike recoveries from dry sediment fortified at 10 microg/kg of each analyte gave lower recoveries but these could also be due to degradation in the matrix. With a smaller volume of aqueous sample required compared to solid-phase extraction (SPE), SPME is an attractive method for the analysis of limited volumes of sediment pore-water. Moreover, the use of SPME eliminated interferences present in sediment extracts thus allowing the detection of the target analytes that were otherwise difficult to detect by direct injection. PMID:15794569

  17. Hollow fiber liquid-liquid-liquid microextraction followed by solid-phase microextraction and in situ derivatization for the determination of chlorophenols by gas chromatography-electron capture detection.

    PubMed

    Saraji, Mohammad; Ghani, Milad

    2015-10-30

    A method based on the combination of hollow fiber liquid-liquid-liquid microextraction and solid-phase microextraction (SPME) followed by gas chromatography-electron capture detection was developed for the determination of chlorophenols in water and wastewater samples. Silica microstructures fabricated on the surface of a stainless steel wire were coated by an organic solvent and used as a SPME fiber. The analytes were extracted through a hollow fiber membrane containing n-decane from sample solution to an alkaline aqueous acceptor phase. They were then extracted and in situ derivatized on the SPME fiber using acetic anhydride. Experimental parameters such as the type of extraction solvent, acceptor phase NaOH concentration, donor phase HCl concentration, the amount of derivatizing reagent, salt concentration, stirring rate and extraction time were investigated and optimized. The precision of the method for the analytes at 0.02-30μgL(-1) concentration level ranged from 7.1 to 10.2% (as intra-day relative standard deviation) and 6.4 to 9.8% (as inter-day relative standard deviation). The linear dynamic ranges were in the interval of 5-500μgL(-1), 0.05-5μgL(-1), 0.02-1μgL(-1) and 0.001-0.5μgL(-1) for 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol, respectively. The enrichment factors were between 432 and 785. The limits of detection were in the range of 0.0004-1.2μgL(-1). Tap water, well water and wastewater samples were also analyzed to evaluate the method capability for real sample analysis. PMID:26411480

  18. Quantification of multi-residue levels in peach juices, pulps and peels using dispersive liquid-liquid microextraction based on floating organic droplet coupled with gas chromatography-electron capture detection.

    PubMed

    Matsadiq, Guzalnur; Hu, Hai-Li; Ren, Hai-Bo; Zhou, Yi-Wen; Liu, Lu; Cheng, Jing

    2011-07-15

    In this paper, polychlorinated biphenyl (PCB), organochlorine pesticide (OCP) and pyrethroid pesticides in peach was investigated by comparing their residual level in peach juice, pulps and peels using dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) combined with gas chromatography-electron capture detection (GC-ECD). Extraction conditions such as the type of extractant, volume of extractant and dispersant, salt effect and extraction time were optimized. For juice samples, the linearity of the method was obtained in the range of 10-2000 ng L(-1),with determination coefficients>0.99. The limits of detection (LOD) of the method were ranged between 2.8 and 18.5 ng L(-1). For pulp and peel samples, the developed method is linear over the range assayed, 1-20 ?g kg(-1),with coefficients also >0.99. The relative recoveries of compounds analyzed from juice, pulp and peel samples were in the range of 73-106% with a relative standard deviation between 2.6 and 11.8%. The proposed method was applied to the simultaneous analysis of residues in real peach juice, pulp and peel samples. As a result, there were no target analytes found in peach juices and pulps while 3.3 ?g kg(-1) cyhalothrin and 3.5 ?g kg(-1) fenvalerate were found in peels. The experiment results revealed that the pyrethroid residues just deposited on the peels of the fruits, but did not move into pulps and juices. PMID:21703950

  19. Suitability of magnetic particle immunoassay for the analysis of PBDEs in Hawaiian freshwater fish and crabs in comparison with gas chromatography/electron capture detection-ion trap mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A gas chromatograph/electron capture detector-ion trap mass spectrometer (GC/ECD-ITMS) was used for the determination of polybrominated diphenyl ethers (PBDEs) in freshwater fish and crabs. The samples were also analyzed with an enzyme-linked immunosorbent assay (ELISA). GC/ECD-ITMS results showed...

  20. FUEL GAS ENVIRONMENTAL IMPACT

    EPA Science Inventory

    The report gives results of continued investigation and further definition of the potential environmental and economic benefits of integrated coal gasification/gas cleanup/combined gas and steam cycle power plants. Reported refinements in plant operating characteristics lower hea...

  1. NPS Gas Gun for Planar Impact Studies

    NASA Astrophysics Data System (ADS)

    Cheong Ho, Chien; Hixson, Robert

    2009-11-01

    The Naval Postgraduate School (NPS) commissioned a Gas Gun for shock wave studies on 9^th October 2009, by performing the first experiment. The Gas Gun is the key element of NPS Shock Wave Research Program within the Physics Department, where well-characterized planar impacts are essential for obtaining high quality data, to characterize a solid material. This first experiment was very successful, and returned key data on the quality of the impact conditions created. The Gas Gun is designed by SANDIA NATIONAL LABORATORIES, and the NPS spent twelve months fabricating the components of the Gas Gun and six months assembling the Gas Gun. Three inch projectile are launched at velocities up to 0.5 km/s, creating high pressure and temperature states that can be used to characterize the fundamental response of relevant materials to dynamic loading. The projectile is launched from a `wrap around' gas breech where helium gas is pressurized to relatively low pressure. This gas is used to accelerate the projectile down a 3m barrel. Upon impact, the speed of the projectile and the flatness of the impact is measured, via a stepped circular pin array circuit. The next stage of development for the Gas Gun is to integrate a Velocity Interferometer System for Any Reflector (VISAR). The VISAR sees all the waves that flow through the target plate as a result of the impact. This is a key diagnostic for determining material properties under dynamic loading conditions.

  2. A gas jet impacting a cavity

    NASA Astrophysics Data System (ADS)

    Bakhsh, H.

    A gas jet impacting a cavity produces secondary jet stagnation temperature much higher than the stagnation temperature of the primary jet. The heating phenomenon from a gas jet cavity impact is investigated. The heating phenomena in resonance tubes and Hilsch vortex tubes is reported. An end wall temperature increase of 235 C is measured in a resonating cavity. A very small hole at the cavity bottom eliminates resonance and produces a secondary jet stagnation temperature identical to the cavity end wall temperature. A secondary jet stagnation temperature increase of 19 C is obtained in high velocity measurements without resonance. Optimum secondary jet temperatures occur in cavities favorable for a good vortex pattern. Flow smoke visualization experiments verified the occurrence of a strong vortex flow at cavity diameter to jet diameter ratios near 1.5.

  3. Impacts of gas drilling on human and animal health.

    PubMed

    Bamberger, Michelle; Oswald, Robert E

    2012-01-01

    Environmental concerns surrounding drilling for gas are intense due to expansion of shale gas drilling operations. Controversy surrounding the impact of drilling on air and water quality has pitted industry and lease-holders against individuals and groups concerned with environmental protection and public health. Because animals often are exposed continually to air, soil, and groundwater and have more frequent reproductive cycles, animals can be used as sentinels to monitor impacts to human health. This study involved interviews with animal owners who live near gas drilling operations. The findings illustrate which aspects of the drilling process may lead to health problems and suggest modifications that would lessen but not eliminate impacts. Complete evidence regarding health impacts of gas drilling cannot be obtained due to incomplete testing and disclosure of chemicals, and nondisclosure agreements. Without rigorous scientific studies, the gas drilling boom sweeping the world will remain an uncontrolled health experiment on an enormous scale. PMID:22446060

  4. Development of impact design methods for ceramic gas turbine components

    NASA Technical Reports Server (NTRS)

    Song, J.; Cuccio, J.; Kington, H.

    1990-01-01

    Impact damage prediction methods are being developed to aid in the design of ceramic gas turbine engine components with improved impact resistance. Two impact damage modes were characterized: local, near the impact site, and structural, usually fast fracture away from the impact site. Local damage to Si3N4 impacted by Si3N4 spherical projectiles consists of ring and/or radial cracks around the impact point. In a mechanistic model being developed, impact damage is characterized as microcrack nucleation and propagation. The extent of damage is measured as volume fraction of microcracks. Model capability is demonstrated by simulating late impact tests. Structural failure is caused by tensile stress during impact exceeding material strength. The EPIC3 code was successfully used to predict blade structural failures in different size particle impacts on radial and axial blades.

  5. The greenhouse impact of unconventional gas for electricity generation

    NASA Astrophysics Data System (ADS)

    Hultman, Nathan; Rebois, Dylan; Scholten, Michael; Ramig, Christopher

    2011-10-01

    New techniques to extract natural gas from unconventional resources have become economically competitive over the past several years, leading to a rapid and largely unanticipated expansion in natural gas production. The US Energy Information Administration projects that unconventional gas will supply nearly half of US gas production by 2035. In addition, by significantly expanding and diversifying the gas supply internationally, the exploitation of new unconventional gas resources has the potential to reshape energy policy at national and international levels—altering geopolitics and energy security, recasting the economics of energy technology investment decisions, and shifting trends in greenhouse gas (GHG) emissions. In anticipation of this expansion, one of the perceived core advantages of unconventional gas—its relatively moderate GHG impact compared to coal—has recently come under scrutiny. In this paper, we compare the GHG footprints of conventional natural gas, unconventional natural gas (i.e. shale gas that has been produced using the process of hydraulic fracturing, or 'fracking'), and coal in a transparent and consistent way, focusing primarily on the electricity generation sector. We show that for electricity generation the GHG impacts of shale gas are 11% higher than those of conventional gas, and only 56% that of coal for standard assumptions.

  6. IMPACT OF AMMONIA UTILIZATION BY NOX FLUE GAS TREATMENT PROCESSES

    EPA Science Inventory

    The report gives results of a study of the impact of ammonia (NH3) utilization by NOx flue gas treatment (FGT) processes. The most technolologically advanced FGT system for the highly efficient (about 90%) removal of NOx from power plang stack gas is selective catalytic reduction...

  7. Chondrule Formation: Nebular Gas Confinement of Impact Splashes

    NASA Astrophysics Data System (ADS)

    Dullemond, Cornelis Petrus; Johansen, Anders

    2013-07-01

    We show that the impact debris from a high-speed collision between two planetesimals during the first few million years would sweep up the nebular gas as a snow plow, leading to deceleration and compression of the debris into a thin shell. This shell breaks up into dense bullets through the Rayleigh-Taylor instability. As a result of the compression by the gas, these bullets will have super-Roche densities and thus will gravitationally collapse to form new planetesimals. Chondrules that may have formed from impact melting would thus rapidly be reaccreted into planetesimals. These dense environments are ideal for forming compound chondrules. The hydrodynamic interaction with the nebular gas could lead to mixing between the newly formed chondrules and surviving pre-impact material. Volatiles can be exchanged between these components in the dense bullets, allowing for chemical complementarity. We believe that this scenario may have some advantages over earlier impact scenarios for chondrule formation.

  8. Production of neutral gas by micrometeoroid impacts

    NASA Astrophysics Data System (ADS)

    Collette, A.; Sternovsky, Z.; Horanyi, M.

    2014-01-01

    We present the first direct laboratory measurement of vapor produced by simulated micrometeoroid bombardment. New in situ observations from the Mercury Surface, Space Environment, Geochemistry and Ranging (MESSENGER) spacecraft, and the anticipation of results from the Lunar Atmosphere and Dust Environment Explorer (LADEE), have highlighted the uncertainty surrounding the role of micrometeoroid impacts in sustaining planetary exospheres. In a recent series of experiments, the quantity of neutral molecules generated by impacts of simulated micrometeorids of 0.1-1 μm radius was measured using a fast ion gauge, over a speed range of 1-10 km/s. The quantity of neutrals released per unit projectile mass, N/m, is consistent with a power law N/m = vβ in the projectile speed v, with β ˜ 2.4. At the highest speeds tested, the number of neutrals liberated is equivalent to 5% of the atoms in the projectile; complete vaporization is projected at speeds exceeding 20 km/s.

  9. Mitigating oil and gas impacts in coastal wetlands

    USGS Publications Warehouse

    Cahoon, Donald R.; Holmes, Joseph C., Jr.

    1989-01-01

    This abstract refers to technical recommendations for avoiding, minimizing, and restoring (i.e., mitigating) drilling site access impacts related to oil and gas activities in coastal wetlands through regulatory review, drawing mostly from the Louisiana experience. The two standard methods used to access wetland drilling locations are canals and roads, both of which require dredging. Each access method impacts wetland values and functions and each has been implicated directly and indirectly in wetland loss by converting marsh habitat to open water or upland habitat and by altering the local hydrologic regime. However, numerous regulatory management techniques exist and should be employed to avoids minimize, and restore canal and road-dump impacts.

  10. Evaluating the income and employment impacts of gas cooling technologies

    SciTech Connect

    Hughes, P.J.; Laitner, S.

    1995-03-01

    The purpose of this study is to estimate the potential employment and income benefits of the emerging market for gas cooling products. The emphasis here is on exports because that is the major opportunity for the U.S. heating, ventilating, and air-conditioning (HVAC) industry. But domestic markets are also important and considered here because without a significant domestic market, it is unlikely that the plant investments, jobs, and income associated with gas cooling exports would be retained within the United States. The prospects for significant gas cooling exports appear promising for a variety of reasons. There is an expanding need for cooling in the developing world, natural gas is widely available, electric infrastructures are over-stressed in many areas, and the cost of building new gas infrastructure is modest compared to the cost of new electric infrastructure. Global gas cooling competition is currently limited, with Japanese and U.S. companies, and their foreign business partners, the only product sources. U.S. manufacturers of HVAC products are well positioned to compete globally, and are already one of the faster growing goods-exporting sectors of the U.S. economy. Net HVAC exports grew by over 800 percent from 1987 to 1992 and currently exceed $2.6 billion annually (ARI 1994). Net gas cooling job and income creation are estimated using an economic input-output model to compare a reference case to a gas cooling scenario. The reference case reflects current policies, practices, and trends with respect to conventional electric cooling technologies. The gas cooling scenario examines the impact of accelerated use of natural gas cooling technologies here and abroad.

  11. Flow reversing in the gas layer in droplet impact

    NASA Astrophysics Data System (ADS)

    Jian, Zhen; Ray, Pascal; Josserand, Christophe; Zaleski, Stephane

    2015-03-01

    Recent numerical and experimental studies demonstrated the crucial role of surrounding gas in droplet impact. Whereas, the mechanism of gas effect in droplet splashing is still far from a crystal clear comprehension. Complicated dynamics occur in a small temporal and spatial scale before direct contact with the target surface, which are related to the origin of the splashing. Direct numerical simulations were executed with a code called Gerris for both droplet impact on a liquid surface and on a solid subtract. New dynamics in the gas layer between the droplet and the target surface were discovered. Unexpectedly, a``reversing'' gas flow (towards the center) is observed as the droplet approaches the target surface. With further descending of the droplet, the flow is reversed and evacuates towards the outside. The reversing of the flow motion direction is followed by the pressure jump and the dimple formation which have been reported as some crucial gas dynamics in droplet splashing mechanism in our previous work. An aerodynamic mechanism is proposed for the flow reversing dynamics.

  12. Simultaneous quantification of ?9-tetrahydrocannabinol, 11-hydroxy-?9-tetrahydrocannabinol, and 11-nor-?9-tetrahydrocannabinol-9-carboxylic acid in human plasma using two-dimensional gas chromatography, cryofocusing, and electron impact-mass spectrometry

    PubMed Central

    Lowe, Ross H.; Karschner, Erin L.; Schwilke, Eugene W.; Barnes, Allan J.; Huestis, Marilyn A.

    2009-01-01

    A two-dimensional (2D) gas chromatography/electron impact-mass spectrometry (GC/EI-MS) method for simultaneous quantification of ?9-tetrahydrocannabinol (THC), 11-hydroxy-?9-tetrahydrocannabinol (11-OH-THC), and 11-nor-?9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) in human plasma was developed and validated. The method employs 2D capillary GC and cryofocusing for enhanced resolution and sensitivity. THC, 11-OH-THC, and THCCOOH were extracted by precipitation with acetonitrile followed by solid-phase extraction. GC separation of trimethylsilyl derivatives of analytes was accomplished with two capillary columns in series coupled via a pneumatic Deans switch system. Detection and quantification were accomplished with a bench-top single quadrupole mass spectrometer operated in electron impact-selected ion monitoring mode. Limits of quantification (LOQ) were 0.125, 0.25 and 0.125 ng/mL for THC, 11-OH-THC, and THCCOOH, respectively. Accuracy ranged from 86.0 to 113.0% for all analytes. Intra- and inter-assay precision, as percent relative standard deviation, was less than 14.1% for THC, 11-OH-THC, and THCCOOH. The method was successfully applied to quantification of THC and its 11-OH-THC and THCCOOH metabolites in plasma specimens following controlled administration of THC. PMID:17640656

  13. Atmospheric emissions and air quality impacts from natural gas production and use.

    PubMed

    Allen, David T

    2014-01-01

    The US Energy Information Administration projects that hydraulic fracturing of shale formations will become a dominant source of domestic natural gas supply over the next several decades, transforming the energy landscape in the United States. However, the environmental impacts associated with fracking for shale gas have made it controversial. This review examines emissions and impacts of air pollutants associated with shale gas production and use. Emissions and impacts of greenhouse gases, photochemically active air pollutants, and toxic air pollutants are described. In addition to the direct atmospheric impacts of expanded natural gas production, indirect effects are also described. Widespread availability of shale gas can drive down natural gas prices, which, in turn, can impact the use patterns for natural gas. Natural gas production and use in electricity generation are used as a case study for examining these indirect consequences of expanded natural gas availability. PMID:24498952

  14. Transport of dissolved gas and its ecological impact after a gas release from deepwater.

    PubMed

    Wimalaratne, Malinda R; Yapa, Poojitha D; Nakata, Kisaburo; Premathilake, Lakshitha T

    2015-11-15

    Previous models on simulating gas releases in deepwater were not focused on the dissolved component and its impact on water quality. This paper presents a new model developed for simulating the transport/spread of dissolved methane from an underwater release and its impact on dissolved oxygen in ambient water. Methane dissolves into ambient water from gas phase, direct from hydrate phase, and from dissociating hydrates formed earlier. Dissolved methane affects the dissolved oxygen levels in ambient water due to microbial interaction and possible direct absorption of oxygen into methane bubbles. We use new model simulations of Deepspill field experiments to compare with instantaneous profiles which were unpublished until now. The comparisons are very good with a short time lag, but are within the acceptable discrepancy for models for emergency response and contingency planning. Scenario simulations show the effect on dissolved oxygen due to different methane release situations. PMID:26364205

  15. Gas chromatography-electron-capture detection of urinary methylhippuric acid isomers as biomarkers of environmental exposure to xylene.

    PubMed

    Buratti, M; Pellegrino, O; Valla, C; Fustinoni, S; Brambilla, G; Colombi, A

    1999-02-19

    Methylhippuric acid isomers (MHAs), urinary metabolites of xylenes, were determined, after clean-up by C18-SPE and esterification with hexafluoroisopropanol and diisopropylcarbodiimide, by GC with ECD detection, on an SPB-35 capillary column (30 m, 0.32 mm I.D., 0.25 microm film thickness, beta = 320). S-benzyl-mercapturic acid was used for internal standardization. Chromatographic conditions were: oven temperature 162 degrees C, for 14.2 min; ramp by 30 degrees C/min to 190 degrees C, for 3.5 min; ramp by 30 degrees C/min to 250 degrees C, for 4 min; helium flow rate: 1.7 ml/min; detector and injector temperature: 300 degrees C. The sample (1 microl) was injected with a split injection technique (split ratio 5:1). MHA recovery was >95% in the 0.5-20 micromol/l range; the limit of detection was <0.25 micromol/l; day-to-day precision, at 2 micromol/l, was Cv<10%. Urinary MHAs were determined in subjects exposed to different low-level sources of xylenes: (a) tobacco smoking habit and (b) BTX urban air pollution (airborne xylene ranging from 0.1 to 3.7 micromol/m3). Study (a) showed a significant difference between urinary MHA median excretion values of nonsmokers and smokers (4.6 micromol/l vs. 8.1 micromol/l, p<0.001). Study (b) revealed a significant difference between indoor workers and outdoor workers (4.3 micromol/l vs. 6.9 micromol/l, p<0.001), and evidenced a relationship between MHAs (y, micromol/mmol creatinine) and airborne xylene (x, micromol/m3) (y = 0.085+0.34x; r = 0.82, p<0.001, n = 56). Proposed biomarkers could represent reliable tools to study very low-level exposure to aromatic hydrocarbons such as those observed in the urban pollution due to vehicular traffic or in indoor air quality evaluation. PMID:10080637

  16. The determination of PCBs in Rocky Flats Type IV waste sludge by gas chromatography/electron capture detection. Part 2

    SciTech Connect

    Parish, K.J.; Applegate, D.V.; Postlethwait, P.D.; Boparai, A.S.; Reedy, G.T.

    1994-12-01

    Before disposal, radioactive sludge (Type IV) from Rocky Flats Plant (RFP) must be evaluated for polychlorinated biphenyl (PCB) content. The Type IV sludge consists of organic solvents, degreasers, cutting oils, and transuranic (TRU) waste mixed with calcium silicate (MicroCel E{reg_sign} and Oil Dri{reg_sign} to form a grease or paste-like material. For laboratory testing, a nonradioactive simulated Type 17V RFP sludge was prepared at Argonne National Laboratory-East (ANL-E). This sludge has a composition similar to that expected from field samples. In an earlier effort, a simplified method was developed for extraction, cleanup of extract, and determination of PCBs in samples of simulated sludge spiked with Aroclors 1254 and 1260. The simplified method has now been used to determine the presence and quantities of other Aroclors in the simulated sludge, namely, Aroclors 10 1 6, 1221, 1232, 1242, and 1248. The accuracy and precision of the data for these Aroclors were found to be similar to the data for sludges spiked with Aroclors 1254 and 1260. Since actual sludges may vary in composition, the method was also verified by analyzing another source of Type IV simulated sludge, prepared by Argonne National Laboratory-West (ANL-W).

  17. Determination of PCBs in Rocky Flats Type IV waste sludge by gas chromatography/electron capture detection

    SciTech Connect

    Parish, K.J.; Applegate, D.V.; Boparai, A.S.; Reedy, G.T.

    1993-12-01

    Type IV Rocky Flats Plant (RFP) radioactive sludge samples must be evaluated for polychlorinated biphenyl (PCB) content before disposal. The Type IV sludge consists of organic solvents, degreasers, cutting oils, and transuranic (TRU) waste mixed with calcium silicate (MicroCel E{reg_sign}) and Oil Dri{reg_sign} to form a grease or paste-like material. For laboratory studies a nonradioactive simulated Type IV RFP sludge was prepared having a composition similar to that expected from field samples. A simplified method was developed for extraction, purification and analysis of PCBs using samples of simulated sludge spiked with Aroclors 1254 and 1260 (reports provided to Argonne indicated Aroclors 1254 and 1260 as the most likely PCB contaminants in RFP sludge samples). The developed method was compared to the Environmental Protection Agency (EPA) accepted SW-846 method for analysis of PCBs (Method 8081). The accuracy and precision data were found to be similar for the two methods. The developed method was also tested with samples of simulated sludge spiked with Pu (in solid and solution forms). Reduction of radioactivity in final extract versus in the spike sample ranged from a factor of 10{sup 5} to 10{sup 7}.

  18. Impact damage on shielded gas-filled vessels

    NASA Astrophysics Data System (ADS)

    Schfer, F.; Schneider, E.; Lambert, M.

    2001-10-01

    This paper gives a summary of the findings from impacts on shielded gas-filled cylindrical aluminium alloy (A12219 T851) and titanium alloy (Ti6A14V) pressure vessels that were performed at the Ernst-Mach-Institute in the frame of an ESA contract. The effect of impacts on shielded vessels with projectiles that have a kinetic energy close to the ballistic limit of the combined system of shield and vessel's front wall was investigated. The shields were single Al-bumper plates, unreinforced MLI and MLI reinforced with 2 layers of Betacloth. The threshold diameters that cause leakage from the vessel's front wall were determined experimentally as a function of shield material and shield spacing. For Al-shielded Al- and Ti-vessels, a safety design factor to avoid leakage is presented based on existing Whipple shield equations.

  19. TRIDENT flyer plate Impact technique: comparison to gas gun plate impact technique

    SciTech Connect

    Darcie D. Koller; George T. Gray III; Sheng-Nian Luo

    2009-03-01

    This report describes the details of a series of plate impact experiments that were conducted on a gas gun in an effort to validate a new technique for plate impact using the TRIDENT laser to launch thin flyers. The diagnostics fielded were VISAR and identical samples and impactors were used on both platforms. All experimenters agree that the VISAR results should have agreed between the two experimental platforms. The VISAR results did not agree across the platforms and experimenters offer explanations and implications for this outcome.

  20. Ozone impacts of natural gas development in the Haynesville Shale.

    PubMed

    Kemball-Cook, Susan; Bar-Ilan, Amnon; Grant, John; Parker, Lynsey; Jung, Jaegun; Santamaria, Wilson; Mathews, Jim; Yarwood, Greg

    2010-12-15

    The Haynesville Shale is a subsurface rock formation located beneath the Northeast Texas/Northwest Louisiana border near Shreveport. This formation is estimated to contain very large recoverable reserves of natural gas, and during the two years since the drilling of the first highly productive wells in 2008, has been the focus of intensive leasing and exploration activity. The development of natural gas resources within the Haynesville Shale is likely to be economically important but may also generate significant emissions of ozone precursors. Using well production data from state regulatory agencies and a review of the available literature, projections of future year Haynesville Shale natural gas production were derived for 2009-2020 for three scenarios corresponding to limited, moderate, and aggressive development. These production estimates were then used to develop an emission inventory for each of the three scenarios. Photochemical modeling of the year 2012 showed increases in 2012 8-h ozone design values of up to 5 ppb within Northeast Texas and Northwest Louisiana resulting from development in the Haynesville Shale. Ozone increases due to Haynesville Shale emissions can affect regions outside Northeast Texas and Northwest Louisiana due to ozone transport. This study evaluates only near-term ozone impacts, but the emission inventory projections indicate that Haynesville emissions may be expected to increase through 2020. PMID:21086985

  1. Atmospheric Impacts of Marcellus Shale Gas Activities in Southwestern Pennsylvania

    NASA Astrophysics Data System (ADS)

    Presto, A. A.; Lipsky, E. M.; Saleh, R.; Donahue, N. M.; Robinson, A. L.

    2012-12-01

    Pittsburgh and the surrounding regions of southwestern Pennsylvania are subject to intensive natural gas exploration, drilling, and extraction associated with the Marcellus Shale formation. Gas extraction from the shale formation uses techniques of horizontal drilling followed by hydraulic fracturing. There are significant concerns about air pollutant emissions from the development and production of shale gas, especially methane emissions. We have deployed a mobile monitoring unit to investigate the atmospheric impacts of Marcellus Shale gas activities. The mobile sampling platform is a van with an on-board generator, a high-resolution GPS unit, cameras, and instrumentation for measuring methane, criteria gases (SO2, NOx, CO, O3), PM size distributions (scanning mobility particle sizer), black carbon mass (multi-angle absorption photometer), particle-bound polycyclic aromatic hydrocarbons, volatile organic compounds (gas chromatograph with flame ionization detection), and meteorological data. A major advantage of the mobile sampling unit over traditional, stationary monitors is that it allows us to rapidly visit a variety of sites. Sampling at multiple sites allows us to characterize the spatial variability of pollutant concentrations related to Marcellus activity, particularly methane. Data collected from the mobile sampling unit are combined with GIS techniques and dispersion models to map pollutants related to Marcellus Shale operations. The Marcellus Shale gas activities are a major and variable source of methane. The background methane concentration in Pittsburgh is 2.1 +/- 0.2 ppm. However, two southwestern Pennsylvania counties with the highest density of Marcellus Shale wells, Washington and Greene Counties, have many areas of elevated methane concentration. Approximately 11% of the sampled sites in Washington County and nearly 50% of the sampled sites in Greene County have elevated (>2.3 ppm) methane concentrations, compared to 1.5% of sites with elevated methane in counties with minimal Marcellus activity (Allegheny and Butler counties). Methane concentrations in areas with large numbers of active well sites can reach as high as 20 ppm (~10 times background), and are highly spatially variable. Areas with elevated methane concentrations also exhibited higher ratios of 13CH4/12CH4, consistent with a thermogenic source of the excess methane.

  2. Review of oil and gas exploitation impacts on grizzly bears

    SciTech Connect

    Schallenberger, A.

    1980-01-01

    It is concluded that available information indicates that impacts of oil and gas exploitation should be considered primarily detrimental for grizzly bears in northwestern Montana. Research has shown that grizzlies tend to react strongly to aircraft, especially helicopters. Marked animals previously captured by aircraft show the greatest reaction. Helicopter disturbance may cause den abandonment. Biologists suggest that road development has contributed to a decline in numbers of bears by accelerating habitat loss and increasing hunting and poaching pressure. Use of river valleys for transportation corridors, campsites, and other activities magnifies the effect of human presence by concentrating it in some of the most vulnerable and essential grizzly habitat. Bear-human conflicts may increase as a result of secondary development such as recreation, logging, livestock grazing, and construction of subdivisions.

  3. How does inhomogeneous reionization impact the gas content of galaxies?

    NASA Astrophysics Data System (ADS)

    Sobacchi, E.; Mesinger, A.

    The reionization of the intergalactic medium (IGM) was likely inhomogeneous and extended. By heating the IGM and photo-evaporating gas from the outskirts of galaxies, this process can have a dramatic impact on the growth of structures and suppress the observed number of dwarf galaxies. We tackle this problem using a tiered approach: combining parameterized results from suites of single-halo collapse simulations with large-scale models of reionization. We present an expression for the halo baryon fraction which is an explicit function of: (i) halo mass; (ii) an ionizing UV background (UVB) intensity; (iii) redshift; (iv) redshift at which the halo was exposed to a UVB. The latter has been shown to significantly impact the observed abundance of local dwarf galaxies. We then fold-in our parametrized results into large-scale simulations of reionization, such that the ionizing emissivity of galaxies depends on the local values of the reionization redshift and the UVB intensity, evolving in a self-consistent manner. We present a physically-motivated analytic expression for the resulting average minimum mass of star-forming galaxies, M_min, which can be readily used in modeling galaxy formation, as well as interpreting observations of dwarf galaxies at all redshifts.

  4. The Impact of Diffuse Ionized Gas on Emission-line Ratios and Gas Metallicity Measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Yan, Renbin; MaNGA Team

    2016-01-01

    Diffuse Ionized Gas (DIG) is prevalent in star-forming galaxies. Using a sample of galaxies observed by MaNGA, we demonstrate how DIG in star-forming galaxies impact the measurements of emission line ratios, hence the gas-phase metallicity measurements and the interpretation of diagnostic diagrams. We demonstrate that emission line surface brightness (SB) is a reasonably good proxy to separate HII regions from regions dominated by diffuse ionized gas. For spatially-adjacent regions or regions at the same radius, many line ratios change systematically with emission line surface brightness, reflecting a gradual increase of dominance by DIG towards low SB. DIG could significantly bias the measurement of gas metallicity and metallicity gradient. Because DIG tend to have a higher temperature than HII regions, at fixed metallicity DIG displays lower [NII]/[OII] ratios. DIG also show lower [OIII]/[OII] ratios than HII regions, due to extended partially-ionized regions that enhance all low-ionization lines ([NII], [SII], [OII], [OI]). The contamination by DIG is responsible for a substantial portion of the scatter in metallicity measurements. At different surface brightness, line ratios and line ratio gradients can differ systematically. As DIG fraction could change with radius, it can affect the metallicity gradient measurements in systematic ways. The three commonly used strong-line metallicity indicators, R23, [NII]/[OII], O3N2, are all affected in different ways. To make robust metallicity gradient measurements, one has to properly isolate HII regions and correct for DIG contamination. In line ratio diagnostic diagrams, contamination by DIG moves HII regions towards composite or LINER-like regions.

  5. 78 FR 19444 - Pawnee National Grassland, Colorado; Oil and Gas Leasing Analysis Environmental Impact Statement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-01

    ... change in the manner in which oil and gas development has occurred on the Pawnee National Grassland... the changed pattern and level of oil and gas development from those effects considered in the 1997... possibly leasing stipulations) to minimize the potential impact of oil and gas development on the...

  6. Air impacts of increased natural gas acquisition, processing, and use: a critical review.

    PubMed

    Moore, Christopher W; Zielinska, Barbara; Pétron, Gabrielle; Jackson, Robert B

    2014-01-01

    During the past decade, technological advancements in the United States and Canada have led to rapid and intensive development of many unconventional natural gas plays (e.g., shale gas, tight sand gas, coal-bed methane), raising concerns about environmental impacts. Here, we summarize the current understanding of local and regional air quality impacts of natural gas extraction, production, and use. Air emissions from the natural gas life cycle include greenhouse gases, ozone precursors (volatile organic compounds and nitrogen oxides), air toxics, and particulates. National and state regulators primarily use generic emission inventories to assess the climate, air quality, and health impacts of natural gas systems. These inventories rely on limited, incomplete, and sometimes outdated emission factors and activity data, based on few measurements. We discuss case studies for specific air impacts grouped by natural gas life cycle segment, summarize the potential benefits of using natural gas over other fossil fuels, and examine national and state emission regulations pertaining to natural gas systems. Finally, we highlight specific gaps in scientific knowledge and suggest that substantial additional measurements of air emissions from the natural gas life cycle are essential to understanding the impacts and benefits of this resource. PMID:24588259

  7. Impact design methods for ceramic components in gas turbine engines

    NASA Technical Reports Server (NTRS)

    Song, J.; Cuccio, J.; Kington, H.

    1991-01-01

    Methods currently under development to design ceramic turbine components with improved impact resistance are presented. Two different modes of impact damage are identified and characterized, i.e., structural damage and local damage. The entire computation is incorporated into the EPIC computer code. Model capability is demonstrated by simulating instrumented plate impact and particle impact tests.

  8. The Economic Impact of Shale Gas Production in the U.S

    NASA Astrophysics Data System (ADS)

    Yang, Yang

    Energy is important to our daily lives. A price change of one energy type may influence our consumption choices, commodities prices and industry production. For the United States, shale gas is becoming a promising source of natural gas because of the rapid increase in its reserve and production capacity. Shale gas production is projected to be a large proportion of U.S. gas production, as predicted by Energy Information Administration (EIA). However, besides knowing the big picture, more details are needed before characterizing shale gas as a "game changer." It is interesting to address questions like to what extent the production of shale gas could affect other industries' production, stabilize commodities' prices, and what are the impacts on factor payments, capital returns, labor payments and household consumption. In this study, I use a CGE model to measure the impact on industry and the change in social welfare associated with shale gas production.

  9. Impacts of winter storms on air-sea gas exchange

    NASA Astrophysics Data System (ADS)

    Zhang, Weiqing; Perrie, Will; Vagle, Svein

    2006-07-01

    The objective of this study is to investigate air-sea gas exchange during winter storms, using field measurements from Ocean Station Papa in the Northeast Pacific (50N, 145W). We show that increasing gas transfer rates are coincident with increasing winds and deepening depth of bubble penetration, and that this process depends on sea state. Wave-breaking is shown to be an important factor in the gas transfer velocity during the peaks of the storms, increasing the flux rates by up to 20%. Gas transfer rates and concentrations can exhibit asymmetry, reflecting a sudden increase with the onset of a storm, and gradual recovery stages.

  10. Shale gas development impacts on surface water quality in Pennsylvania

    PubMed Central

    Olmstead, Sheila M.; Muehlenbachs, Lucija A.; Shih, Jhih-Shyang; Chu, Ziyan; Krupnick, Alan J.

    2013-01-01

    Concern has been raised in the scientific literature about the environmental implications of extracting natural gas from deep shale formations, and published studies suggest that shale gas development may affect local groundwater quality. The potential for surface water quality degradation has been discussed in prior work, although no empirical analysis of this issue has been published. The potential for large-scale surface water quality degradation has affected regulatory approaches to shale gas development in some US states, despite the dearth of evidence. This paper conducts a large-scale examination of the extent to which shale gas development activities affect surface water quality. Focusing on the Marcellus Shale in Pennsylvania, we estimate the effect of shale gas wells and the release of treated shale gas waste by permitted treatment facilities on observed downstream concentrations of chloride (Cl−) and total suspended solids (TSS), controlling for other factors. Results suggest that (i) the treatment of shale gas waste by treatment plants in a watershed raises downstream Cl− concentrations but not TSS concentrations, and (ii) the presence of shale gas wells in a watershed raises downstream TSS concentrations but not Cl− concentrations. These results can inform future voluntary measures taken by shale gas operators and policy approaches taken by regulators to protect surface water quality as the scale of this economically important activity increases. PMID:23479604

  11. Shale gas development impacts on surface water quality in Pennsylvania.

    PubMed

    Olmstead, Sheila M; Muehlenbachs, Lucija A; Shih, Jhih-Shyang; Chu, Ziyan; Krupnick, Alan J

    2013-03-26

    Concern has been raised in the scientific literature about the environmental implications of extracting natural gas from deep shale formations, and published studies suggest that shale gas development may affect local groundwater quality. The potential for surface water quality degradation has been discussed in prior work, although no empirical analysis of this issue has been published. The potential for large-scale surface water quality degradation has affected regulatory approaches to shale gas development in some US states, despite the dearth of evidence. This paper conducts a large-scale examination of the extent to which shale gas development activities affect surface water quality. Focusing on the Marcellus Shale in Pennsylvania, we estimate the effect of shale gas wells and the release of treated shale gas waste by permitted treatment facilities on observed downstream concentrations of chloride (Cl(-)) and total suspended solids (TSS), controlling for other factors. Results suggest that (i) the treatment of shale gas waste by treatment plants in a watershed raises downstream Cl(-) concentrations but not TSS concentrations, and (ii) the presence of shale gas wells in a watershed raises downstream TSS concentrations but not Cl(-) concentrations. These results can inform future voluntary measures taken by shale gas operators and policy approaches taken by regulators to protect surface water quality as the scale of this economically important activity increases. PMID:23479604

  12. Social impacts of earthquakes caused by gas extraction in the Province of Groningen, The Netherlands

    SciTech Connect

    Voort, Nick van der Vanclay, Frank

    2015-01-15

    Gas extraction from the Groningen gasfield in the northern Netherlands has led to localised earthquakes which are projected to become more severe. The social impacts experienced by local residents include: damage to property; declining house prices; concerns about the chance of dykes breaking; feelings of anxiety and insecurity; health issues; and anger. These social and emotional impacts are exacerbated by the increasing distrust Groningen people have towards the national government and the gas company, NAM, a partnership between Shell and ExxonMobil. The earthquakes have reopened discussions about the distribution of benefits from gas production and the extent to which benefits are retained locally. Mitigation of the impacts is attempted, but the lack of trust decreases the effectiveness of the mitigation measures. The extent of this experience of previously-unforeseen, unanticipated impacts suggests that a new social and environmental impact assessment needs to be undertaken, and a new Social Impact Management Plan (SIMP) and Impacts and Benefits Agreement (IBA) developed, so that the project can regain its legitimacy and social licence to operate. In addition to conventional gas, this paper has wider relevance for unconventional gas developments, for example shale gas extraction by hydraulic fracturing methods (fracking). - Highlights: • Gas production in Groningen has caused over 1000 earthquakes. • The induced seismicity has caused many social impacts. • Impacts include building damage, reduced house prices, fear and health issues. • Mitigation measures attempted to date are inadequate. • Distrust towards the national government and operator hinders mitigation efforts. • Gas production in Groningen has lost its social licence to operate.

  13. Volcanic gas impacts on vegetation at Turrialba Volcano, Costa Rica

    NASA Astrophysics Data System (ADS)

    Teasdale, R.; Jenkins, M.; Pushnik, J.; Houpis, J. L.; Brown, D. L.

    2010-12-01

    Turrialba volcano is an active composite stratovolcano that is located approximately 40 km east of San Jose, Costa Rica. Seismic activity and degassing have increased since 2005, and gas compositions reflect further increased activity since 2007 peaking in January 2010 with a phreatic eruption. Gas fumes dispersed by trade winds toward the west, northwest, and southwest flanks of Turrialba volcano have caused significant vegetation kill zones, in areas important to local agriculture, including dairy pastures and potato fields, wildlife and human populations. In addition to extensive vegetative degradation is the potential for soil and water contamination and soil erosion. Summit fumarole temperatures have been measured over 200 degrees C and gas emissions are dominated by SO2; gas and vapor plumes reach up to 2 km (fumaroles and gases are measured regularly by OVSICORI-UNA). A recent network of passive air sampling, monitoring of water temperatures of hydrothermal systems, and soil pH measurements coupled with measurement of the physiological status of surrounding plants using gas exchange and fluorescence measurements to: (1) identify physiological correlations between leaf-level gas exchange and chlorophyll fluorescence measurements of plants under long term stress induced by the volcanic gas emissions, and (2) use measurements in tandem with remotely sensed reflectance-derived fluorescence ratio indices to track natural photo inhibition caused by volcanic gas emissions, for use in monitoring plant stress and photosynthetic function. Results may prove helpful in developing potential land management strategies to maintain the biological health of the area.

  14. Impact of Gas Heating in Inductively Coupled Plasmas

    NASA Technical Reports Server (NTRS)

    Hash, D. B.; Bose, D.; Rao, M. V. V. S.; Cruden, B. A.; Meyyappan, M.; Sharma, S. P.; Biegel, Bryan (Technical Monitor)

    2001-01-01

    Recently it has been recognized that the neutral gas in inductively coupled plasma reactors heats up significantly during processing. The resulting gas density variations across the reactor affect reaction rates, radical densities, plasma characteristics, and uniformity within the reactor. A self-consistent model that couples the plasma generation and transport to the gas flow and heating has been developed and used to study CF4 discharges. A Langmuir probe has been used to measure radial profiles of electron density and temperature. The model predictions agree well with the experimental results. As a result of these comparisons along with the poorer performance of the model without the gas-plasma coupling, the importance of gas heating in plasma processing has been verified.

  15. THE IMPACT OF MUNICIPAL SOLID WASTE MANAGEMENT ON GREENHOUSE GAS EMISSIONS IN THE UNITED STATES

    EPA Science Inventory

    Technological advancements in United States (U.S.) municipal solid waste (MSW) disposal and a focus on the environmental advantages of integrated MSW management have greatly reduced the environmental impacts of MSW management, including greenhouse gas (GHG) emissions. This study ...

  16. Impacts of Unconventional Gas Technology in the Annual Energy Outlook 2000

    EIA Publications

    2000-01-01

    This paper describes the methodology used in the National Energy Modeling System (NEMS) to represent unconventional gas technologies and their impacts on projections in the Annual Energy Outlook 2000 (AEO2000).

  17. Socioeconomic impacts of outer continental shelf oil and gas development; a bibliography

    USGS Publications Warehouse

    Pattison, Malka L.

    1977-01-01

    The bibliography lists reports which are concerned primarily with the socioeconomic impacts of OCS oil and gas development or which, although not primarily concerned with such impacts, include sections that contain significant discussion of them. Several of the cited reports do not address socioeconomic issues directly, but have been included because of their value in providing a broad picture of OCS oil and gas development and the associated terminology and/or techical aspects. (Sinha - OEIS)

  18. Impact of tillage and fertilizer application method on gas emissions in a corn cropping system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tillage and fertilization practices used in row crop production are thought to alter greenhouse gas emissions from soil. This study was conducted to determine the impact of fertilizer sources, land management practices, and fertilizer placement methods on greenhouse gas emissions. A new prototype i...

  19. Integrated Analysis of Greenhouse Gas Mitigation Options and Related Impacts

    EPA Science Inventory

    Increased concerns over air pollution (combined with detrimental health effects) and climate change have called for more stringent emission reduction strategies for criteria air pollutants and greenhouse gas emissions. However, stringent regulatory policies can possibly have a...

  20. Impact of shale gas development on regional water quality.

    PubMed

    Vidic, R D; Brantley, S L; Vandenbossche, J M; Yoxtheimer, D; Abad, J D

    2013-05-17

    Unconventional natural gas resources offer an opportunity to access a relatively clean fossil fuel that could potentially lead to energy independence for some countries. Horizontal drilling and hydraulic fracturing make the extraction of tightly bound natural gas from shale formations economically feasible. These technologies are not free from environmental risks, however, especially those related to regional water quality, such as gas migration, contaminant transport through induced and natural fractures, wastewater discharge, and accidental spills. We review the current understanding of environmental issues associated with unconventional gas extraction. Improved understanding of the fate and transport of contaminants of concern and increased long-term monitoring and data dissemination will help manage these water-quality risks today and in the future. PMID:23687049

  1. Environmental baseline conditions for impact assessment of unconventional gas exploitation: the G-Baseline project

    NASA Astrophysics Data System (ADS)

    Kloppmann, Wolfram; Mayer, Berhard; Millot, Romain; Parker, Beth L.; Gaucher, Eric; Clarkson, Christopher R.; Cherry, John A.; Humez, Pauline; Cahill, Aaron

    2015-04-01

    A major scientific challenge and an indispensible prerequisite for environmental impact assessment in the context of unconventional gas development is the determination of the baseline conditions against which potential environmental impacts on shallow freshwater resources can be accurately and quantitatively tested. Groundwater and surface water resources overlying the low-permeability hydrocarbon host rocks containing shale gas may be impacted to different extents by naturally occurring saline fluids and by natural gas emanations. Baseline assessments in areas of previous conventional hydrocarbon production may also reveal anthropogenic impacts from these activities not related to unconventional gas development. Once unconventional gas exploitation has started, the baseline may be irrevocably lost by the intricate superposition of geogenic and potential anthropogenic contamination by stray gas, formation waters and chemicals used during hydraulic fracturing. The objective of the Franco-Canadian NSERC-ANR project G-Baseline is to develop an innovative and comprehensive methodology of geochemical and isotopic characterization of the environmental baseline for water and gas samples from all three essential zones: (1) the production zone, including flowback waters, (2) the intermediate zone comprised of overlying formations, and (3) shallow aquifers and surface water systems where contamination may result from diverse natural or human impacts. The outcome will be the establishment of a methodology based on innovative tracer and monitoring techniques, including traditional and non-traditional isotopes (C, H, O, S, B, Sr, Cl, Br, N, U, Li, Cu, Zn, CSIA...) for detecting, quantifying and modeling of potential leakage of stray gas and of saline formation water mixed with flowback fluids into fresh groundwater resources and surface waters taking into account the pathways and mechanisms of fluid and gas migration. Here we present an outline of the project as well as first results from chemical and isotopic analyses on gas, fluid and solid samples collected during a baseline monitoring program at the Carbon Management Canada field research site in south-eastern Alberta, Canada.

  2. Hydraulic fracturing for natural gas: impact on health and environment.

    PubMed

    Carpenter, David O

    2016-03-01

    Shale deposits exist in many parts of the world and contain relatively large amounts of natural gas and oil. Recent technological developments in the process of horizontal hydraulic fracturing (hydrofracturing or fracking) have suddenly made it economically feasible to extract natural gas from shale. While natural gas is a much cleaner burning fuel than coal, there are a number of significant threats to human health from the extraction process as currently practiced. There are immediate threats to health resulting from air pollution from volatile organic compounds, which contain carcinogens such as benzene and ethyl-benzene, and which have adverse neurologic and respiratory effects. Hydrogen sulfide, a component of natural gas, is a potent neuro- and respiratory toxin. In addition, levels of formaldehyde are elevated around fracking sites due to truck traffic and conversion of methane to formaldehyde by sunlight. There are major concerns about water contamination because the chemicals used can get into both ground and surface water. Much of the produced water (up to 40% of what is injected) comes back out of the gas well with significant radioactivity because radium in subsurface rock is relatively water soluble. There are significant long-term threats beyond cancer, including exacerbation of climate change due to the release of methane into the atmosphere, and increased earthquake activity due to disruption of subsurface tectonic plates. While fracking for natural gas has significant economic benefits, and while natural gas is theoretically a better fossil fuel as compared to coal and oil, current fracking practices pose significant adverse health effects to workers and near-by residents. The health of the public should not be compromized simply for the economic benefits to the industry. PMID:26943595

  3. 76 FR 22734 - South Carolina Electric and Gas; Notice of Availability of the Final Environmental Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-22

    ... Engineers as a cooperating agency have published a final environmental impact statement (EIS), NUREG-1939, Final Environmental Impact Statement for Combined Licenses for Virgil C. Summer Nuclear Station, Units 2... COMMISSION South Carolina Electric and Gas; Notice of Availability of the Final Environmental...

  4. Limited impact on decadal-scale climate change from increased use of natural gas.

    PubMed

    McJeon, Haewon; Edmonds, Jae; Bauer, Nico; Clarke, Leon; Fisher, Brian; Flannery, Brian P; Hilaire, Jérôme; Krey, Volker; Marangoni, Giacomo; Mi, Raymond; Riahi, Keywan; Rogner, Holger; Tavoni, Massimo

    2014-10-23

    The most important energy development of the past decade has been the wide deployment of hydraulic fracturing technologies that enable the production of previously uneconomic shale gas resources in North America. If these advanced gas production technologies were to be deployed globally, the energy market could see a large influx of economically competitive unconventional gas resources. The climate implications of such abundant natural gas have been hotly debated. Some researchers have observed that abundant natural gas substituting for coal could reduce carbon dioxide (CO2) emissions. Others have reported that the non-CO2 greenhouse gas emissions associated with shale gas production make its lifecycle emissions higher than those of coal. Assessment of the full impact of abundant gas on climate change requires an integrated approach to the global energy-economy-climate systems, but the literature has been limited in either its geographic scope or its coverage of greenhouse gases. Here we show that market-driven increases in global supplies of unconventional natural gas do not discernibly reduce the trajectory of greenhouse gas emissions or climate forcing. Our results, based on simulations from five state-of-the-art integrated assessment models of energy-economy-climate systems independently forced by an abundant gas scenario, project large additional natural gas consumption of up to +170 per cent by 2050. The impact on CO2 emissions, however, is found to be much smaller (from -2 per cent to +11 per cent), and a majority of the models reported a small increase in climate forcing (from -0.3 per cent to +7 per cent) associated with the increased use of abundant gas. Our results show that although market penetration of globally abundant gas may substantially change the future energy system, it is not necessarily an effective substitute for climate change mitigation policy. PMID:25317557

  5. Wellbeing Impacts of City Policies for Reducing Greenhouse Gas Emissions

    PubMed Central

    Hiscock, Rosemary; Mudu, Pierpaolo; Braubach, Matthias; Martuzzi, Marco; Perez, Laura; Sabel, Clive

    2014-01-01

    To mitigate climate change, city authorities are developing policies in areas such as transportation, housing and energy use, to reduce greenhouse gas emissions. In addition to their effects on greenhouse gas emissions, these policies are likely to have consequences for the wellbeing of their populations for example through changes in opportunities to take physical exercise. In order to explore the potential consequences for wellbeing, we first explore what ‘wellbeing’ is and how it can be operationalized for urban planners. In this paper, we illustrate how wellbeing can be divided into objective and subjective aspects which can be measured quantitatively; our review of measures informs the development of a theoretical model linking wellbeing to policies which cities use to reduce greenhouse gas emissions. Finally, we discuss the extent to which the links proposed in the conceptual model are supported by the literature and how cities can assess wellbeing implications of policies. PMID:25464129

  6. Wellbeing impacts of city policies for reducing greenhouse gas emissions.

    PubMed

    Hiscock, Rosemary; Mudu, Pierpaolo; Braubach, Matthias; Martuzzi, Marco; Perez, Laura; Sabel, Clive

    2014-12-01

    To mitigate climate change, city authorities are developing policies in areas such as transportation, housing and energy use, to reduce greenhouse gas emissions. In addition to their effects on greenhouse gas emissions, these policies are likely to have consequences for the wellbeing of their populations for example through changes in opportunities to take physical exercise. In order to explore the potential consequences for wellbeing, we first explore what 'wellbeing' is and how it can be operationalised for urban planners. In this paper, we illustrate how wellbeing can be divided into objective and subjective aspects which can be measured quantitatively; our review of measures informs the development of a theoretical model linking wellbeing to policies which cities use to reduce greenhouse gas emissions. Finally, we discuss the extent to which the links proposed in the conceptual model are supported by the literature and how cities can assess wellbeing implications of policies. PMID:25464129

  7. Impact of Adsorption on Gas Transport in Nanopores

    PubMed Central

    Wu, Tianhao; Zhang, Dongxiao

    2016-01-01

    Given the complex nature of the interaction between gas and solid atoms, the development of nanoscale science and technology has engendered a need for further understanding of gas transport behavior through nanopores and more tractable models for large-scale simulations. In the present paper, we utilize molecular dynamic simulations to demonstrate the behavior of gas flow under the influence of adsorption in nano-channels consisting of illite and graphene, respectively. The results indicate that velocity oscillation exists along the cross-section of the nano-channel, and the total mass flow could be either enhanced or reduced depending on variations in adsorption under different conditions. The mechanisms can be explained by the extra average perturbation stress arising from density oscillation via the novel perturbation model for micro-scale simulation, and approximated via the novel dual-region model for macro-scale simulation, which leads to a more accurate permeability correction model for industrial applications than is currently available.

  8. Impacts of Imported Liquefied Natural Gas on Residential Appliance Components: Literature Review

    SciTech Connect

    Lekov, Alex; Sturges, Andy; Wong-Parodi, Gabrielle

    2009-12-09

    An increasing share of natural gas supplies distributed to residential appliances in the U.S. may come from liquefied natural gas (LNG) imports. The imported gas will be of a higher Wobbe number than domestic gas, and there is concern that it could produce more pollutant emissions at the point of use. This report will review recently undertaken studies, some of which have observed substantial effects on various appliances when operated on different mixtures of imported LNG. While we will summarize findings of major studies, we will not try to characterize broad effects of LNG, but describe how different components of the appliance itself will be affected by imported LNG. This paper considers how the operation of each major component of the gas appliances may be impacted by a switch to LNG, and how this local impact may affect overall safety, performance and pollutant emissions.

  9. Comparing the ecological impacts of wind and oil & gas development: a landscape scale assessment.

    PubMed

    Jones, Nathan F; Pejchar, Liba

    2013-01-01

    Energy production in the United States is in transition as the demand for clean and domestic power increases. Wind energy offers the benefit of reduced emissions, yet, like oil and natural gas, it also contributes to energy sprawl. We used a diverse set of indicators to quantify the ecological impacts of oil, natural gas, and wind energy development in Colorado and Wyoming. Aerial imagery was supplemented with empirical data to estimate habitat loss, fragmentation, potential for wildlife mortality, susceptibility to invasion, biomass carbon lost, and water resources. To quantify these impacts we digitized the land-use footprint within 375 plots, stratified by energy type. We quantified the change in impacts per unit area and per unit energy produced, compared wind energy to oil and gas, and compared landscapes with and without energy development. We found substantial differences in impacts between energy types for most indicators, although the magnitude and direction of the differences varied. Oil and gas generally resulted in greater impacts per unit area but fewer impacts per unit energy compared with wind. Biologically important and policy-relevant outcomes of this study include: 1) regardless of energy type, underlying land-use matters and development in already disturbed areas resulted in fewer total impacts; 2) the number and source of potential mortality varied between energy types, however, the lack of robust mortality data limits our ability to use this information to estimate and mitigate impacts; and 3) per unit energy produced, oil and gas extraction was less impactful on an annual basis but is likely to have a much larger cumulative footprint than wind energy over time. This rapid evaluation of landscape-scale energy development impacts could be replicated in other regions, and our specific findings can help meet the challenge of balancing land conservation with society's demand for energy. PMID:24312296

  10. Comparing the Ecological Impacts of Wind and Oil & Gas Development: A Landscape Scale Assessment

    PubMed Central

    Jones, Nathan F.; Pejchar, Liba

    2013-01-01

    Energy production in the United States is in transition as the demand for clean and domestic power increases. Wind energy offers the benefit of reduced emissions, yet, like oil and natural gas, it also contributes to energy sprawl. We used a diverse set of indicators to quantify the ecological impacts of oil, natural gas, and wind energy development in Colorado and Wyoming. Aerial imagery was supplemented with empirical data to estimate habitat loss, fragmentation, potential for wildlife mortality, susceptibility to invasion, biomass carbon lost, and water resources. To quantify these impacts we digitized the land-use footprint within 375 plots, stratified by energy type. We quantified the change in impacts per unit area and per unit energy produced, compared wind energy to oil and gas, and compared landscapes with and without energy development. We found substantial differences in impacts between energy types for most indicators, although the magnitude and direction of the differences varied. Oil and gas generally resulted in greater impacts per unit area but fewer impacts per unit energy compared with wind. Biologically important and policy-relevant outcomes of this study include: 1) regardless of energy type, underlying land-use matters and development in already disturbed areas resulted in fewer total impacts; 2) the number and source of potential mortality varied between energy types, however, the lack of robust mortality data limits our ability to use this information to estimate and mitigate impacts; and 3) per unit energy produced, oil and gas extraction was less impactful on an annual basis but is likely to have a much larger cumulative footprint than wind energy over time. This rapid evaluation of landscape-scale energy development impacts could be replicated in other regions, and our specific findings can help meet the challenge of balancing land conservation with society’s demand for energy. PMID:24312296

  11. Energy Market Impacts of Alternative Greenhouse Gas Intensity Reduction Goals

    EIA Publications

    2006-01-01

    This report responds to a request from Senator Ken Salazar that the Energy Information Administration (EIA) analyze the impacts of implementing alternative variants of an emissions cap-and-trade program for greenhouse gases (GHGs).

  12. The impact of ice layers on gas transport through firn

    NASA Astrophysics Data System (ADS)

    Keegan, K.; Albert, M. R.; Baker, I.

    2014-02-01

    Typically, gas transport through firn is modeled in the context of an idealized firn column. However, in natural firn, imperfections are present which may alter transport dynamics in ways that may reduce the accuracy of climate records. For example, ice layers have been found in several firn cores collected in the polar regions. Here, we examined the effects of two ice layers found in a NEEM, Greenland firn core on gas transport through the firn. Both ice layers were somewhat permeable. However, only the shallower ice layer was significantly less permeable than the surrounding firn and is therefore likely to retard gas transport. Large closed bubbles were found in one ice layer, which would contain older atmospheric samples than expected. Theses bubbles are likely to significantly bias age estimates. Conversely, the permeability and thickness of ice layers at NEEM suggest that they will not significantly bias the expected firn air concentration profiles at the present spatial resolution at which these data are collected. Therefore, ice layers do not need to be accounted for in gas transport models at NEEM. However, the microstructure of these ice layers indicates that larger melting events could significantly bias ice core records.

  13. Life cycle greenhouse gas impacts of grassland management practice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biomass from conservation and dedicated grasslands could be an important feedstock for biofuels. Estimating the carbon (C) intensity of biofuel production pathways is important in order to meet greenhouse gas (GHG) targets set by government policy. Management decisions made during feedstock producti...

  14. The greenhouse impact of unconventional gas for electricity generation

    NASA Astrophysics Data System (ADS)

    Hultman, Nathan; Rebois, Dylan; Scholten, Michael; Ramig, Christopher

    2011-12-01

    In our discussion of the use of global warming potential (GWP) values in the Howarth et al (2011) paper, our text implies that the GISS group's 2009 and 2010 papers (Shindell et al 2009 and Unger et al 2010) were contradictory. Such an interpretation does not reflect the conclusions of those papers and was not our intention. First, the 2009 and 2010 papers address GWP and radiative forcing, respectively. Our intentions in that paragraph were (a) to illustrate the possible ways that the GWP and radiative forcing discussions in the scientific community were misapplied to lifecycle analysis of greenhouse gas emissions from unconventional gas extraction, and (b) to underscore that the reasonable questions about GWP raised by Shindell et al (2009) are a justification for retaining a broader, rather than narrower, range of GWP possibilities for this calculation. References Howarth R W, Santoro R and Ingraffea A 2011 Methane and the greenhouse-gas footprint of natural gas from shale formations Clim. Change Lett. 106 679-90 Shindell D T, Faluvegi G, Koch D M, Schmidt G A, Unger N and Bauer S E 2009 Improved attribution of climate forcing to emissions Science 326 716-8 Unger N, Bond T C, Wang J S, Koch D M, Menon S, Shindell D T and Bauer S E 2010 Attribution of climate forcing to economic sectors Proc. Natl Acad. Sci. 107 3382-7

  15. 75 FR 51839 - Environmental Impact Statement for Oil and Gas Development Activities on the Uintah and Ouray...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-23

    ... Bureau of Indian Affairs Environmental Impact Statement for Oil and Gas Development Activities on the... Environmental Impact Statement (EIS) that evaluates proposed oil and gas development activities on the Uintah... understanding of oil and gas development alternatives on the Reservation, and their existing and...

  16. 76 FR 35009 - Draft Oil and Gas Management Plan/Environmental Impact Statement for Big South Fork National...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-15

    ... are particularly susceptible to adverse impacts from oil and gas development. Authority: The authority... and gas management plan for BISO and OBRI was published in the Federal Register on May 31, 2006 (71 FR... National Park Service Draft Oil and Gas Management Plan/Environmental Impact Statement for Big South...

  17. Synergies and Tradeoffs Among Environmental Impacts Under Conservation Planning of Shale Gas Surface Infrastructure

    NASA Astrophysics Data System (ADS)

    Milt, Austin W.; Gagnolet, Tamara; Armsworth, Paul R.

    2016-01-01

    Hydraulic fracturing and related ground water issues are growing features in public discourse. Few have given much attention to surface impacts from shale gas development, which result from building necessary surface infrastructure. One way to reduce future impacts from gas surface development without radically changing industry practice is by formulating simple, conservation-oriented planning guidelines. We explore how four such guidelines affect the locations of well pads, access roads, and gathering pipelines on state lands in Pennsylvania. Our four guidelines aim to (1) reduce impacts on water, reduce impacts from (2) gathering pipelines and (3) access roads, and (4) reduce impacts on forests. We assessed whether the use of such guidelines accompanies tradeoffs among impacts, and if any guidelines perform better than others at avoiding impacts. We find that impacts are mostly synergistic, such that avoiding one impact will result in avoiding others. However, we found that avoiding forest fragmentation may result in increased impacts on other environmental features. We also found that single simple planning guidelines can be effective in targeted situations, but no one guideline was universally optimal in avoiding all impacts. As such, we suggest that when multiple environmental features are important in an area, more comprehensive planning strategies and tools should be used.

  18. Synergies and Tradeoffs Among Environmental Impacts Under Conservation Planning of Shale Gas Surface Infrastructure.

    PubMed

    Milt, Austin W; Gagnolet, Tamara; Armsworth, Paul R

    2016-01-01

    Hydraulic fracturing and related ground water issues are growing features in public discourse. Few have given much attention to surface impacts from shale gas development, which result from building necessary surface infrastructure. One way to reduce future impacts from gas surface development without radically changing industry practice is by formulating simple, conservation-oriented planning guidelines. We explore how four such guidelines affect the locations of well pads, access roads, and gathering pipelines on state lands in Pennsylvania. Our four guidelines aim to (1) reduce impacts on water, reduce impacts from (2) gathering pipelines and (3) access roads, and (4) reduce impacts on forests. We assessed whether the use of such guidelines accompanies tradeoffs among impacts, and if any guidelines perform better than others at avoiding impacts. We find that impacts are mostly synergistic, such that avoiding one impact will result in avoiding others. However, we found that avoiding forest fragmentation may result in increased impacts on other environmental features. We also found that single simple planning guidelines can be effective in targeted situations, but no one guideline was universally optimal in avoiding all impacts. As such, we suggest that when multiple environmental features are important in an area, more comprehensive planning strategies and tools should be used. PMID:26275668

  19. Impacts of Coal Seam Gas (Coal Bed Methane) Extraction on Water Resources in Australia

    NASA Astrophysics Data System (ADS)

    Post, David

    2014-05-01

    While extraction of methane from shale gas deposits has been the principal source of the recent expansion of the industry in the United States and potentially in Europe, extraction of methane from coal bed methane deposits (termed 'coal seam gas' in Australia) has been the focus in Australia. The two sources of methane share many of the same characteristics, with hydraulic fracturing generally (but not always) required to extract coal seam gas also. However, as coal seam gas deposits generally occur at shallower depths than shale gas, the potential impacts of extraction and hydraulic fracturing on surface and groundwater resources may be potentially of more concern for coal seam gas than for shale gas. To determine the potential for coal seam gas extraction (and coal mining more generally) to impact on water resources and water-related assets in Australia, the Commonwealth Government has recently established an Independent Expert Scientific Committee (the IESC) to provide advice to Commonwealth and State Government regulators on potential water-related impacts of coal seam gas and large coal mining developments. The IESC has in turn implemented a program of research termed 'bioregional assessments' to investigate these potential impacts. A bioregional assessment can be defined as a scientific analysis of the ecology, hydrology, geology and hydrogeology of a bioregion, with explicit assessment of the potential direct, indirect and cumulative impacts of coal seam gas and large coal mining development on water resources. These bioregional assessments are now being carried out across large portions of eastern Australia which are underlain by coal reserves. Further details of the program can be found at http://www.environment.gov.au/coal-seam-gas-mining/bioregional-assessments.html. This presentation will provide an overview of the issues related to the impacts of coal seam gas extraction on surface and groundwater resources and water-related assets in Australia. The methodology of undertaking bioregional assessments will be described, and the application of this methodology to six priority bioregions in eastern Australia will be detailed. Preliminary results of the program of research to date will be assessed in light of the requirements of the IESC to provide independent advice to the Australian Commonwealth and State Governments. Finally, parallels (and differences) between the expansion of the industry in Australia with that in the United States and Europe will be drawn.

  20. Impacts of Sixteen Different Biochars on Soil Greenhouse Gas Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One potential abatement strategy to increasing atmospheric levels of carbon dioxide (CO2) is to sequester atmospheric CO2 captured through photosynthesis in biomass and pyrolysed into a more stable form of carbon called biochar. We evaluated the impacts of 16 different biochars from different pyroly...

  1. Volatile organic compound emissions from unconventional natural gas production: Source signatures and air quality impacts

    NASA Astrophysics Data System (ADS)

    Swarthout, Robert F.

    Advances in horizontal drilling and hydraulic fracturing over the past two decades have allowed access to previously unrecoverable reservoirs of natural gas and led to an increase in natural gas production. Intensive unconventional natural gas extraction has led to concerns about impacts on air quality. Unconventional natural gas production has the potential to emit vast quantities of volatile organic compounds (VOCs) into the atmosphere. Many VOCs can be toxic, can produce ground-level ozone or secondary organic aerosols, and can impact climate. This dissertation presents the results of experiments designed to validate VOC measurement techniques, to quantify VOC emission rates from natural gas sources, to identify source signatures specific to natural gas emissions, and to quantify the impacts of these emissions on potential ozone formation and human health. Measurement campaigns were conducted in two natural gas production regions: the Denver-Julesburg Basin in northeast Colorado and the Marcellus Shale region surrounding Pittsburgh, Pennsylvania. An informal measurement intercomparison validated the canister sampling methodology used throughout this dissertation for the measurement of oxygenated VOCs. Mixing ratios of many VOCs measured during both campaigns were similar to or higher than those observed in polluted cities. Fluxes of natural gas-associated VOCs in Colorado ranged from 1.5-3 times industry estimates. Similar emission ratios relative to propane were observed for C2-C6 alkanes in both regions, and an isopentane:n-pentane ratio ≈1 was identified as a unique tracer for natural gas emissions. Source apportionment estimates indicated that natural gas emissions were responsible for the majority of C2-C8 alkanes observed in each region, but accounted for a small proportion of alkenes and aromatic compounds. Natural gas emissions in both regions accounted for approximately 20% of hydroxyl radical reactivity, which could hinder federal ozone standard compliance in downwind cities. A health risk assessment showed no increase in cancer or chronic non-cancer risk at locations near natural gas wells in Pennsylvania, but the contribution of natural gas emissions to total risk was 3-6 times higher near wells. These results will assist policy makers, natural gas producers, and citizen stakeholders in crafting effective policies to control VOC emissions from natural gas production activities.

  2. Impact of numerical integration on gas curtain simulations

    SciTech Connect

    Rider, W.; Kamm, J.

    2000-11-01

    In recent years, we have presented a less than glowing experimental comparison of hydrodynamic codes with the gas curtain experiment (e.g., Kamm et al. 1999a). Here, we discuss the manner in which the details of the hydrodynamic integration techniques may conspire to produce poor results. This also includes some progress in improving the results and agreement with experimental results. Because our comparison was conducted on the details of the experimental images (i.e., their detailed structural information), our results do not conflict with previously published results of good agreement with Richtmyer-Meshkov instabilities based on the integral scale of mixing. New experimental and analysis techniques are also discussed.

  3. Massive gas injections in JET - Impact on wall conditions

    NASA Astrophysics Data System (ADS)

    Jet Efda Contributors Kruezi, Uron; Lehnen, M.; Philipps, V.; Brezinsek, S.; Sergienko, G.; Bozenkhov, S.; Jachmich, S.; Morgan, P. D.; Matthews, G. F.

    2011-08-01

    Disruptions are a critical issue for large scale tokamaks due to the potential damage to plasma facing components. Massive Gas Injection (MGI) is considered as a 'last resort' method for disruption mitigation. A MGI system based on the Disruption Mitigation Valve (DMV) has been brought into operation at JET. Injections of neon, argon and its mixtures with deuterium show distinct effects on the machine condition during and after MGI-induced disruptions. MGI with pure argon shows a continuous accumulation in consecutive pulses. Neon on the contrary shows a fast saturation due to trapping in carbon PFCs.

  4. Impacts of Coal Seam Gas (Coal Bed Methane) and Coal Mining on Water Resources in Australia

    NASA Astrophysics Data System (ADS)

    Post, D. A.

    2013-12-01

    Mining of coal bed methane deposits (termed ';coal seam gas' in Australia) is a rapidly growing source of natural gas in Australia. Indeed, expansion of the industry is occurring so quickly that in some cases, legislation is struggling to keep up with this expansion. Perhaps because of this, community concern about the impacts of coal seam gas development is very strong. Responding to these concerns, the Australian Government has recently established an Independent Expert Scientific Committee (IESC) to provide advice to the Commonwealth and state regulators on potential water-related impacts of coal seam gas and large coal mining developments. In order to provide the underlying science to the IESC, a program of ';bioregional assessments' has been implemented. One aim of these bioregional assessments is to improve our understanding of the connectivity between the impacts of coal seam gas extraction and groundwater aquifers, as well as their connection to surface water. A bioregional assessment can be defined as a scientific analysis of the ecology, hydrology, geology and hydrogeology of a bioregion, with explicit assessment of the potential direct, indirect and cumulative impacts of coal seam gas and large coal mining development on water resources. These bioregional assessments are now being carried out across large portions of eastern Australia which are underlain by coal reserves. This presentation will provide an overview of the issues related to the impacts of coal seam gas and coal mining on water resources in Australia. The methodology of undertaking bioregional assessments will be described, and the application of this methodology to six priority bioregions in eastern Australia will be detailed. Preliminary results of the program of research to date will be assessed in light of the requirements of the IESC to provide independent advice to the Commonwealth and State governments. Finally, parallels between the expansion of the industry in Australia with that in the United States will be drawn.

  5. Gas phase plasma impact on phenolic compounds in pomegranate juice.

    PubMed

    Herceg, Zoran; Kova?evi?, Danijela Bursa?; Kljusuri?, Jasenka Gajdo; Jambrak, Anet Reek; Zori?, Zoran; Dragovi?-Uzelac, Verica

    2016-01-01

    The aim of the study was to evaluate the effect of gas phase plasma on phenolic compounds in pomegranate juice. The potential of near infrared reflectance spectroscopy combined with partial least squares for monitoring the stability of phenolic compounds during plasma treatment was explored, too. Experiments are designed to investigate the effect of plasma operating conditions (treatment time 3, 5, 7 min; sample volume 3, 4, 5 cm(3); gas flow 0.75, 1, 1.25 dm(3) min(-1)) on phenolic compounds and compared to pasteurized and untreated pomegranate juice. Pasteurization and plasma treatment resulted in total phenolic content increasing by 29.55% and 33.03%, respectively. Principal component analysis and sensitivity analysis outputted the optimal treatment design with plasma that could match the pasteurized sample concerning the phenolic stability (5 min/4 cm(3)/0.75 dm(3) min(-1)). Obtained results demonstrate the potential of near infrared reflectance spectroscopy that can be successfully used to evaluate the quality of pomegranate juice upon plasma treatment considering the phenolic compounds. PMID:26213024

  6. Impact of Shale Gas Development on Water Resources: A Case Study in Northern Poland

    NASA Astrophysics Data System (ADS)

    Vandecasteele, Ine; Marí Rivero, Inés; Sala, Serenella; Baranzelli, Claudia; Barranco, Ricardo; Batelaan, Okke; Lavalle, Carlo

    2015-06-01

    Shale gas is currently being explored in Europe as an alternative energy source to conventional oil and gas. There is, however, increasing concern about the potential environmental impacts of shale gas extraction by hydraulic fracturing (fracking). In this study, we focussed on the potential impacts on regional water resources within the Baltic Basin in Poland, both in terms of quantity and quality. The future development of the shale play was modeled for the time period 2015-2030 using the LUISA modeling framework. We formulated two scenarios which took into account the large range in technology and resource requirements, as well as two additional scenarios based on the current legislation and the potential restrictions which could be put in place. According to these scenarios, between 0.03 and 0.86 % of the total water withdrawals for all sectors could be attributed to shale gas exploitation within the study area. A screening-level assessment of the potential impact of the chemicals commonly used in fracking was carried out and showed that due to their wide range of physicochemical properties, these chemicals may pose additional pressure on freshwater ecosystems. The legislation put in place also influenced the resulting environmental impacts of shale gas extraction. Especially important are the protection of vulnerable ground and surface water resources and the promotion of more water-efficient technologies.

  7. Impact of shale gas development on water resources: a case study in northern poland.

    PubMed

    Vandecasteele, Ine; Marí Rivero, Inés; Sala, Serenella; Baranzelli, Claudia; Barranco, Ricardo; Batelaan, Okke; Lavalle, Carlo

    2015-06-01

    Shale gas is currently being explored in Europe as an alternative energy source to conventional oil and gas. There is, however, increasing concern about the potential environmental impacts of shale gas extraction by hydraulic fracturing (fracking). In this study, we focussed on the potential impacts on regional water resources within the Baltic Basin in Poland, both in terms of quantity and quality. The future development of the shale play was modeled for the time period 2015-2030 using the LUISA modeling framework. We formulated two scenarios which took into account the large range in technology and resource requirements, as well as two additional scenarios based on the current legislation and the potential restrictions which could be put in place. According to these scenarios, between 0.03 and 0.86% of the total water withdrawals for all sectors could be attributed to shale gas exploitation within the study area. A screening-level assessment of the potential impact of the chemicals commonly used in fracking was carried out and showed that due to their wide range of physicochemical properties, these chemicals may pose additional pressure on freshwater ecosystems. The legislation put in place also influenced the resulting environmental impacts of shale gas extraction. Especially important are the protection of vulnerable ground and surface water resources and the promotion of more water-efficient technologies. PMID:25877457

  8. Mapping Oil and Gas Development Potential in the US Intermountain West and Estimating Impacts to Species

    PubMed Central

    Copeland, Holly E.; Doherty, Kevin E.; Naugle, David E.; Pocewicz, Amy; Kiesecker, Joseph M.

    2009-01-01

    Background Many studies have quantified the indirect effect of hydrocarbon-based economies on climate change and biodiversity, concluding that a significant proportion of species will be threatened with extinction. However, few studies have measured the direct effect of new energy production infrastructure on species persistence. Methodology/Principal Findings We propose a systematic way to forecast patterns of future energy development and calculate impacts to species using spatially-explicit predictive modeling techniques to estimate oil and gas potential and create development build-out scenarios by seeding the landscape with oil and gas wells based on underlying potential. We illustrate our approach for the greater sage-grouse (Centrocercus urophasianus) in the western US and translate the build-out scenarios into estimated impacts on sage-grouse. We project that future oil and gas development will cause a 7–19 percent decline from 2007 sage-grouse lek population counts and impact 3.7 million ha of sagebrush shrublands and 1.1 million ha of grasslands in the study area. Conclusions/Significance Maps of where oil and gas development is anticipated in the US Intermountain West can be used by decision-makers intent on minimizing impacts to sage-grouse. This analysis also provides a general framework for using predictive models and build-out scenarios to anticipate impacts to species. These predictive models and build-out scenarios allow tradeoffs to be considered between species conservation and energy development prior to implementation. PMID:19826472

  9. Plasma jet's shielding gas impact on bacterial inactivation.

    PubMed

    Jablonowski, Helena; Hnsch, Mareike A Ch; Dnnbier, Mario; Wende, Kristian; Hammer, Malte U; Weltmann, Klaus-Dieter; Reuter, Stephan; Woedtke, Thomas von

    2015-01-01

    One of the most desired aims in plasma medicine is to inactivate prokaryotic cells and leave eukaryotic cells unharmed or even stimulate proliferation to promote wound healing. The method of choice is to precisely control the plasma component composition. Here the authors investigate the inactivation of bacteria (Escherichia coli) by a plasma jet treatment. The reactive species composition created by the plasma in liquids is tuned by the use of a shielding gas device to achieve a reactive nitrogen species dominated condition or a reactive oxygen species dominated condition. A strong correlation between composition of the reactive components and the inactivation of the bacteria is observed. The authors compare the results to earlier investigations on eukaryotic cells and show that it is possible to find a plasma composition where bacterial inactivation is strongest and adverse effects on eukaryotic cells are minimized. PMID:25832438

  10. Impact of compressed natural gas fueled buses on street pavements

    SciTech Connect

    Yang, D.; Harrison, R.

    1995-07-01

    Capital Metro, the Ausin, Texas transit authority, is currently evaluating a number of CNG fueled buses. As part of the U.S. DOT Region Six University Transportation Centers Program (UTCP), a study was instigated into the scale of incremental pavement consumption associated with the operation of these buses. The study suggests that replacing current vehicles with CNG powered models utilizing aluminum storage tanks would raise average network equivalent single rehabilitation costs across the network of over four percent. Finally, it recommends that full cost study be undertaken with evaluation of the adoption of alternative bus fuels - which includes pavement and environmental impacts.

  11. Environmental impacts of food trade via resource use and greenhouse gas emissions

    NASA Astrophysics Data System (ADS)

    Dalin, Carole; Rodríguez-Iturbe, Ignacio

    2016-03-01

    Agriculture will need to significantly intensify in the next decades to continue providing essential nutritive food to a growing global population. However, it can have harmful environmental impacts, due to the use of natural and synthetic resources and the emission of greenhouse gases, which alter the water, carbon and nitrogen cycles, and threaten the fertility, health and biodiversity of landscapes. Because of the spatial heterogeneity of resource productivity, farming practices, climate, and land and water availability, the environmental impact of producing food is highly dependent on its origin. For this reason, food trade can either increase or reduce the overall environmental impacts of agriculture, depending on whether or not the impact is greater in the exporting region. Here, we review current scientific understanding of the environmental impacts of food trade, focusing on water and land use, pollution and greenhouse gas emissions. In the case of water, these impacts are mainly beneficial. However, in the cases of pollution and greenhouse gas emissions, this conclusion is not as clear. Overall, there is an urgent need for a more comprehensive, integrated approach to estimate the global impacts of food trade on the environment. Second, research is needed to improve the evaluation of some key aspects of the relative value of each resource depending on the local and regional biophysical and socio–economic context. Finally, to enhance the impact of such evaluations and their applicability in decision-making, scenario analyses and accounting of key issues like deforestation and groundwater exhaustion will be required.

  12. IMPACT OF NOX SELECTIVE CATALYTIC REDUCTION PROCESSES ON FLUE GAS CLEANING SYSTEMS

    EPA Science Inventory

    The report gives results of a study of the impact of the ammonia leaving a nitrogen oxide (NOx) selective catalytic reduction (SCR) process on downstream flue gas cleaning processes. (NOx emissions from electric utility boilers may be reduced 80-90% by the application of pollutio...

  13. Field ionization kinetic and electron impact studies of gas phase transition states - The cyclic bromonium ion

    NASA Technical Reports Server (NTRS)

    Green, M. M.; Giguere, R. J.; Falick, A. M.; Aberth, W.; Burlingame, A. L.

    1978-01-01

    Cis- and trans-isomers of 4-t-butylcyclohexyl bromide were studied to determine the mechanism of cyclic bromonium ion formation. The field ionization kinetic and electron impact data indicate that the formation of the cyclic structure occurs simultaneously with loss of the neutral fragment. The data also show that little or no gas-phase cis-trans isomerization occurs.

  14. Environmental impacts of energy facilities: fuel cell technology compared with coal and conventional gas technology

    NASA Astrophysics Data System (ADS)

    Seip, Knut L.; Thorstensen, Bernt; Wang, Hagbarth

    We compare the environmental side effects of power plants based on fuel cell technology with the side effects of conventional electric power plants based on coal and natural gas. The environmental impact of a solid oxide fuel cell (SOFC) plant is very much less than that of a coal-fired plant (a factor of {1}/{300} for air pollution and a factor of {1}/{5} for water pollution). Compared with a conventional gas plant, impact is reduced by between 50 and 98%. Damage to cultural monuments and buildings is negligible from a fuel cell plant. Socioeconomic negative impacts are reduced by about 30% relative to conventional gas plants (aesthetics and noise) whereas employment is unaltered. Impact on health and safety is greatly reduced compared with that from coal-fired plants and is about 70% of that from conventional gas plants. Preliminary results suggest that society's willingness to pay (WTP) for clean air, and thereby better health, matches the cost of installing emission-reducing equipment on conventional power plants. There is probably an additional WTP for other benefits (e.g., decreased risk of global warming). Thus, the utility of very small emissions, lower CO 2 discharges, and other benefits from SOFC generators may compensate for the increased cost incurred in producing electricity by SOFC generators.

  15. EVALUATION OF VAPOR EQUILIBRATION AND IMPACT OF PURGE VOLUME ON SOIL-GAS SAMPLING RESULTS

    EPA Science Inventory

    Sequential sampling was utilized at the Raymark Superfund site to evaluate attainment of vapor equilibration and the impact of purge volume on soil-gas sample results. A simple mass-balance equation indicates that removal of three to five internal volumes of a sample system shou...

  16. Physicochemical impacts associated with natural gas development on methanogenesis in deep sand aquifers.

    PubMed

    Katayama, Taiki; Yoshioka, Hideyoshi; Muramoto, Yoshiyuki; Usami, Jun; Fujiwara, Kazuhiro; Yoshida, Satoshi; Kamagata, Yoichi; Sakata, Susumu

    2015-02-01

    The Minami-Kanto gas field, where gases are dissolved in formation water, is a potential analogue for a marine gas hydrate area because both areas are characterized by the accumulation of microbial methane in marine turbidite sand layers interbedded with mud layers. This study examined the physicochemical impacts associated with natural gas production and well drilling on the methanogenic activity and composition in this gas field. Twenty-four gas-associated formation water samples were collected from confined sand aquifers through production wells. The stable isotopic compositions of methane in the gases indicated their origin to be biogenic via the carbonate reduction pathway. Consistent with this classification, methanogenic activity measurements using radiotracers, culturing experiments and molecular analysis of formation water samples indicated the predominance of hydrogenotrophic methanogenesis. The cultivation of water samples amended only with methanogenic substrates resulted in significant increases in microbial cells along with high-yield methane production, indicating the restricted availability of substrates in the aquifers. Hydrogenotrophic methanogenic activity increased with increasing natural gas production from the corresponding wells, suggesting that the flux of substrates from organic-rich mudstones to adjacent sand aquifers is enhanced by the decrease in fluid pressure in sand layers associated with natural gas/water production. The transient predominance of methylotrophic methanogens, observed for a few years after well drilling, also suggested the stimulation of the methanogens by the exposure of unutilized organic matter through well drilling. These results provide an insight into the physicochemical impacts on the methanogenic activity in biogenic gas deposits including marine gas hydrates. PMID:25105906

  17. Physicochemical impacts associated with natural gas development on methanogenesis in deep sand aquifers

    PubMed Central

    Katayama, Taiki; Yoshioka, Hideyoshi; Muramoto, Yoshiyuki; Usami, Jun; Fujiwara, Kazuhiro; Yoshida, Satoshi; Kamagata, Yoichi; Sakata, Susumu

    2015-01-01

    The Minami-Kanto gas field, where gases are dissolved in formation water, is a potential analogue for a marine gas hydrate area because both areas are characterized by the accumulation of microbial methane in marine turbidite sand layers interbedded with mud layers. This study examined the physicochemical impacts associated with natural gas production and well drilling on the methanogenic activity and composition in this gas field. Twenty-four gas-associated formation water samples were collected from confined sand aquifers through production wells. The stable isotopic compositions of methane in the gases indicated their origin to be biogenic via the carbonate reduction pathway. Consistent with this classification, methanogenic activity measurements using radiotracers, culturing experiments and molecular analysis of formation water samples indicated the predominance of hydrogenotrophic methanogenesis. The cultivation of water samples amended only with methanogenic substrates resulted in significant increases in microbial cells along with high-yield methane production, indicating the restricted availability of substrates in the aquifers. Hydrogenotrophic methanogenic activity increased with increasing natural gas production from the corresponding wells, suggesting that the flux of substrates from organic-rich mudstones to adjacent sand aquifers is enhanced by the decrease in fluid pressure in sand layers associated with natural gas/water production. The transient predominance of methylotrophic methanogens, observed for a few years after well drilling, also suggested the stimulation of the methanogens by the exposure of unutilized organic matter through well drilling. These results provide an insight into the physicochemical impacts on the methanogenic activity in biogenic gas deposits including marine gas hydrates. PMID:25105906

  18. Impacts of Coal Seam Gas (Coal Bed Methane) Extraction on Water Resources in Australia

    NASA Astrophysics Data System (ADS)

    Post, David

    2015-04-01

    While extraction of methane from shale gas deposits has been the principal source of the recent expansion of the industry in the United States and Europe, in Australia extraction of methane from coal bed methane deposits (termed 'coal seam gas' in Australia) has been the focus to date. The two sources of methane share many of the same characteristics including the potential requirement for hydraulic fracturing. However as coal seam gas deposits generally occur at shallower depths than shale gas the potential impacts of extraction and hydraulic fracturing on surface and groundwater resources may be of even greater concern for coal seam gas than for shale gas. In Australia an Independent Expert Scientific Committee (IESC) has been established to provide scientific advice to federal and state government regulators on the impact that coal seam gas and large coal mining developments may have on water resources. This advice is provided to enable decisions to be informed by the best available science about the potential water-related impacts associated with these developments. To support this advice the Australian Government Department of the Environment has implemented a three-year programme of research termed 'bioregional assessments' to investigate these potential impacts. A bioregional assessment is defined as a scientific analysis of the ecology, hydrology, geology and hydrogeology of a bioregion with explicit assessment of the potential direct, indirect and cumulative impacts of coal seam gas and large coal mining development on water resources. These bioregional assessments are currently being carried out across large portions of eastern Australia underlain by coal reserves. Further details of the program and results to date can be found at http://www.bioregionalassessments.gov.au. In this presentation the methodology for undertaking bioregional assessments will be described and the application of this methodology to six priority bioregions in eastern Australia will be detailed. Results of the programme to date will be provided (being nearly two years into the three-year study) with a focus on the preliminary results of numerical groundwater modelling. Once completed this modelling will be used to evaluate the impacts of the depressurisation of coal seams on aquifers and associated ecological, economic and socio-cultural water-dependent assets.

  19. The Use of Health Impact Assessment for a Community Undergoing Natural Gas Development

    PubMed Central

    McKenzie, Lisa; Stinson, Kaylan E.; Scott, Kenneth; Newman, Lee S.; Adgate, John

    2013-01-01

    The development of natural gas wells is rapidly increasing, yet little is known about associated exposures and potential public health consequences. We used health impact assessment (HIA) to provide decision-makers with information to promote public health at a time of rapid decision making for natural gas development. We have reported that natural gas development may expose local residents to air and water contamination, industrial noise and traffic, and community changes. We have provided more than 90 recommendations for preventing or decreasing health impacts associated with these exposures. We also have reflected on the lessons learned from conducting an HIA in a politically charged environment. Finally, we have demonstrated that despite the challenges, HIA can successfully enhance public health policymaking. PMID:23597363

  20. Evaluating greenhouse gas impacts of organic waste management options using life cycle assessment.

    PubMed

    Kong, Dung; Shan, Jilei; Iacoboni, Mario; Maguin, Stephen R

    2012-08-01

    Efforts to divert organics away from landfills are viewed by many as an important measure to significantly reduce the climate change impacts of municipal solid waste management. However, the actual greenhouse gas (GHG) impacts of organics diversion from landfills have yet to be thoroughly evaluated and whether such a diversion provides significant environmental benefits in terms of GHG impacts must be answered. This study, using California-specific information, aimed to analyse the GHG impacts of organics diversion through a life-cycle assessment (LCA). This LCA considered all aspects of organics management including transportation, materials handling, GHG emissions, landfill gas capture/utilization, energy impacts, and carbon sequestration. The LCA study evaluated overall GHG impacts of landfilling, and alternative management options such as composting and anaerobic digestion for diverted organic waste. The LCA analysis resulted in net GHG reductions of 0.093, 0.048, 0.065 and 0.073 tonnes carbon equivalent per tonne organic waste for landfilling, windrow composting, aerated static pile composting, and anaerobic digestion, respectively. This study confirms that all three options for organics management result in net reductions of GHG emissions, but it also shows that organics landfilling, when well-managed, generates greater GHG reductions. The LCA provides scientific insight with regards to the environmental impacts of organics management options, which should be considered in decision and policy-making. The study also highlights the importance of how site and case-specific conditions influence project outcomes when considering organic waste management options. PMID:22588112

  1. Recent natural gas mergers/alliances and their impact on processing

    SciTech Connect

    Kovacs, K.; Schwenker, C.

    1997-12-31

    Recent mergers and acquisitions have dramatically changed the competitive landscape for companies in the oil, gas and energy services businesses. One measure of this change is the number of publicly traded oil and gas producers in the US. Prior to 1991 the Oil and Gas Journal listed 400 publicly traded producers. This list shrank in 1991 to 300, and as of 1996, the list is now down to 200 in their annual survey. The purpose of this paper is to: briefly review some of the underlying factors or events that have shaped or driven the rush to consolidate; discuss how these changes have impacted gas processing; finally, make some observations on the types of consolidations and opportunities that could occur in the future.

  2. Investigating links between shale gas development and health impacts through a community survey project in Pennsylvania.

    PubMed

    Steinzor, Nadia; Subra, Wilma; Sumi, Lisa

    2013-01-01

    Across the United States, the race for new energy sources is picking up speed and reaching more places, with natural gas in the lead. While the toxic and polluting qualities of substances used and produced in shale gas development and the general health effects of exposure are well established, scientific evidence of causal links has been limited, creating an urgent need to understand health impacts. Self-reported survey research documenting the symptoms experienced by people living in proximity to gas facilities, coupled with environmental testing, can elucidate plausible links that warrant both response and further investigation. This method, recently applied to the gas development areas of Pennsylvania, indicates the need for a range of policy and research efforts to safeguard public health. PMID:23552648

  3. Impacts of Marcellus Shale Natural Gas Production on Regional Air Quality

    NASA Astrophysics Data System (ADS)

    Swarthout, R.; Russo, R. S.; Zhou, Y.; Mitchell, B.; Miller, B.; Lipsky, E. M.; Sive, B. C.

    2012-12-01

    Natural gas is a clean burning alternative to other fossil fuels, producing lower carbon dioxide (CO2) emissions during combustion. Gas deposits located within shale rock or tight sand formations are difficult to access using conventional drilling techniques. However, horizontal drilling coupled with hydraulic fracturing is now widely used to enhance natural gas extraction. Potential environmental impacts of these practices are currently being assessed because of the rapid expansion of natural gas production in the U.S. Natural gas production has contributed to the deterioration of air quality in several regions, such as in Wyoming and Utah, that were near or downwind of natural gas basins. We conducted a field campaign in southwestern Pennsylvania on 16-18 June 2012 to investigate the impact of gas production operations in the Marcellus Shale on regional air quality. A total of 235 whole air samples were collected in 2-liter electropolished stainless- steel canisters throughout southwestern Pennsylvania in a regular grid pattern that covered an area of approximately 8500 square km. Day and night samples were collected at each grid point and additional samples were collected near active wells, flaring wells, fluid retention reservoirs, transmission pipelines, and a processing plant to assess the influence of different stages of the gas production operation on emissions. The samples were analyzed at Appalachian State University for methane (CH4), CO2, C2-C10 nonmethane hydrocarbons (NMHCs), C1-C2 halocarbons, C1-C5 alkyl nitrates and selected reduced sulfur compounds. In-situ measurements of ozone (O3), CH4, CO2, nitric oxide (NO), total reactive nitrogen (NOy), formaldehyde (HCHO), and a range of volatile organic compounds (VOCs) were carried out at an upwind site and a site near active gas wells using a mobile lab. Emissions associated with gas production were observed throughout the study region. Elevated mixing ratios of CH4 and CO2 were observed in the southwest and northeast portions of the study area indicating multiple emission sources. We also present comparisons of VOC fingerprints observed in the Marcellus Shale to our previous observations of natural gas emissions from the Denver-Julesburg Basin in northeast Colorado to identify tracers for these different natural gas sources.

  4. Study of Damage of Gas-filled Spherical Pressure Vassel Subjected to Hypervelocity Impact by Space Debris with Different Velocity

    NASA Astrophysics Data System (ADS)

    Cai, Yuan; Pang, Baojun; Jia, Bin

    2013-08-01

    As an important component of spacecraft, if a gas-filled pressure vessel is impacted by space debris, it might occur even overall bursting. Spherical aluminum projectiles are used to simulate space debris impacting gas-filled spherical pressure vessel with hypervelocity. Projectiles impact places with the same thickness in different tests. By analyzing the maximum gas pressure of the spherical vessel, the inflation pressure is determined: 1.075MPa. By numerical simulation, the critical impact velocity to perforate the front wall is determined: 2.02mm ~ 2.31mm. As the projectile velocity increases, the damage patterns of the back wall are of different bulged outwards patterns.

  5. Gas range/oven emissions impact analysis: appendix. Final report, July 1985-December 1987

    SciTech Connect

    Tikalsky, S.; Reisdorf, K.; Flickinger, J.; Totzke, D.; Haywood, J.

    1987-12-01

    Ten older homes in Wisconsin were selected to participate in the pilot project to determine if field measurements of NO/sub 2/ and CO on gas ranges vary significantly from those reported in the literature, and if use of both vented and unvented gas appliances can be apportioned to determine separate impacts. Continuous NO/sub 2/ and CO measurements were taken in several locations within each home during two measurement periods. Homeowners also kept detailed diaries of gas-appliance use. The results indicate that the gas oven was frequently implicated in the small group of case study homes as a source of peak hourly average NO/sub 2/ concentrations; NO/sub 2/ emission rates were as much as a factor of two greater than those previously reported. The study also found that routine service adjustments on the ten-range set resulted in statistically significant decreases in CO and NO/sub 2/ emission rates following servicing. This finding implies that some servicing of the gas range may be desirable and have an impact on indoor levels of NO/sub 2/ and CO.

  6. Incorporating the effect of gas in modelling the impact of CBM extraction on regional groundwater systems

    NASA Astrophysics Data System (ADS)

    Herckenrath, Daan; Doherty, John; Panday, Sorab

    2015-04-01

    Production of Coalbed Methane (CBM) requires extraction of large quantities of groundwater. To date, standard groundwater flow simulators have mostly been used to assess the impact of this extraction on regional groundwater systems. Recent research has demonstrated that predictions of regional impact assessment made by such models may be seriously compromised unless account is taken of the presence of a gas phase near extraction wells. At the same time, CBM impact assessment must accommodate the traditional requirements of regional groundwater modelling. These include representation of surficial groundwater processes and up-scaled rock properties as well as the need for calibration and predictive uncertainty quantification. The study documented herein (1) quantifies errors in regional drawdown predictions incurred through neglect of the presence of a gas phase near CBM extraction centres, and (2) evaluates the extent to which these errors can be mitigated by simulating near-well desaturation using a modified Richards equation formulation within a standard groundwater flow simulator. Two synthetic examples are provided to quantify the impact of the gas phase and verify the proposed modelling approach (implemented in MODFLOW-USG) against rigorous multiphase flow simulations (undertaken using ECLIPSE)

  7. Ice Target and Gas Target Experiments in the IMPACT Dust Accelerator

    NASA Astrophysics Data System (ADS)

    Munsat, T. L.; Collette, A.; Dee, R.; Gruen, E.; Horanyi, M.; James, D.; Janches, D.; Kempf, S.; Plane, J. M. C.; Shu, A. J.; Simolka, J.; Sternovsky, Z.; Thomas, E.

    2014-12-01

    The dust accelerator facility at the SSERVI Institute for Modeling Plasma, Atmospheres, and Cosmic Dust (IMPACT) is presently implementing two major target upgrades: a cryogenic ice target and a high-pressure gas target. The ice target consists of a LN2 cryogenic system connected to both a water-ice deposition system as well as a movable freezer/holder for a pre-mixed liquid cartridge. Planned experiments include the bombardment of a variety of frozen targets and simulated ice/regolith mixtures, and the assessment of all impact products (solid ejecta, gas, plasma) as well as spectroscopy of both the impact-produced light flashes and the reflected spectra (UV, visible, IR). Such measurements are highly relevant to both physical and chemical surface modification of airless bodies due to micrometeoroid impacts. The gas target consists of a differentially pumped chamber kept at moderate background pressures, such that high-velocity (~10 km/s) micrometeoroids are completely ablated within 10's of cm (i.e. within the measurement chamber). The chamber is configured with segmented electrodes to perform a spatially-resolved measurement of charge production during ablation, and localized light-collection optics enable an assessment of the light production (luminous efficiency). Such studies are critical to the understanding of past and future ground-based measurements of meteor ablation in Earth's atmosphere, which in turn can potentially provide the best estimates of the interplanetary dust particle flux.

  8. Life cycle water consumption and wastewater generation impacts of a Marcellus shale gas well.

    PubMed

    Jiang, Mohan; Hendrickson, Chris T; VanBriesen, Jeanne M

    2014-01-01

    This study estimates the life cycle water consumption and wastewater generation impacts of a Marcellus shale gas well from its construction to end of life. Direct water consumption at the well site was assessed by analysis of data from approximately 500 individual well completion reports collected in 2010 by the Pennsylvania Department of Conservation and Natural Resources. Indirect water consumption for supply chain production at each life cycle stage of the well was estimated using the economic input-output life cycle assessment (EIO-LCA) method. Life cycle direct and indirect water quality pollution impacts were assessed and compared using the tool for the reduction and assessment of chemical and other environmental impacts (TRACI). Wastewater treatment cost was proposed as an additional indicator for water quality pollution impacts from shale gas well wastewater. Four water management scenarios for Marcellus shale well wastewater were assessed: current conditions in Pennsylvania; complete discharge; direct reuse and desalination; and complete desalination. The results show that under the current conditions, an average Marcellus shale gas well consumes 20,000 m(3) (with a range from 6700 to 33,000 m(3)) of freshwater per well over its life cycle excluding final gas utilization, with 65% direct water consumption at the well site and 35% indirect water consumption across the supply chain production. If all flowback and produced water is released into the environment without treatment, direct wastewater from a Marcellus shale gas well is estimated to have 300-3000 kg N-eq eutrophication potential, 900-23,000 kg 2,4D-eq freshwater ecotoxicity potential, 0-370 kg benzene-eq carcinogenic potential, and 2800-71,000 MT toluene-eq noncarcinogenic potential. The potential toxicity of the chemicals in the wastewater from the well site exceeds those associated with supply chain production, except for carcinogenic effects. If all the Marcellus shale well wastewater is treated to surface discharge standards by desalination, $59,000-270,000 per well would be required. The life cycle study results indicate that when gas end use is not considered hydraulic fracturing is the largest contributor to the life cycle water impacts of a Marcellus shale gas well. PMID:24380628

  9. Life Cycle Water Consumption and Wastewater Generation Impacts of a Marcellus Shale Gas Well

    PubMed Central

    2013-01-01

    This study estimates the life cycle water consumption and wastewater generation impacts of a Marcellus shale gas well from its construction to end of life. Direct water consumption at the well site was assessed by analysis of data from approximately 500 individual well completion reports collected in 2010 by the Pennsylvania Department of Conservation and Natural Resources. Indirect water consumption for supply chain production at each life cycle stage of the well was estimated using the economic input–output life cycle assessment (EIO-LCA) method. Life cycle direct and indirect water quality pollution impacts were assessed and compared using the tool for the reduction and assessment of chemical and other environmental impacts (TRACI). Wastewater treatment cost was proposed as an additional indicator for water quality pollution impacts from shale gas well wastewater. Four water management scenarios for Marcellus shale well wastewater were assessed: current conditions in Pennsylvania; complete discharge; direct reuse and desalination; and complete desalination. The results show that under the current conditions, an average Marcellus shale gas well consumes 20 000 m3 (with a range from 6700 to 33 000 m3) of freshwater per well over its life cycle excluding final gas utilization, with 65% direct water consumption at the well site and 35% indirect water consumption across the supply chain production. If all flowback and produced water is released into the environment without treatment, direct wastewater from a Marcellus shale gas well is estimated to have 300–3000 kg N-eq eutrophication potential, 900–23 000 kg 2,4D-eq freshwater ecotoxicity potential, 0–370 kg benzene-eq carcinogenic potential, and 2800–71 000 MT toluene-eq noncarcinogenic potential. The potential toxicity of the chemicals in the wastewater from the well site exceeds those associated with supply chain production, except for carcinogenic effects. If all the Marcellus shale well wastewater is treated to surface discharge standards by desalination, $59 000–270 000 per well would be required. The life cycle study results indicate that when gas end use is not considered hydraulic fracturing is the largest contributor to the life cycle water impacts of a Marcellus shale gas well. PMID:24380628

  10. The economic impact of shale gas development on state and local economies: benefits, costs, and uncertainties.

    PubMed

    Barth, Jannette M

    2013-01-01

    It is often assumed that natural gas exploration and development in the Marcellus Shale will bring great economic prosperity to state and local economies. Policymakers need accurate economic information on which to base decisions regarding permitting and regulation of shale gas extraction. This paper provides a summary review of research findings on the economic impacts of extractive industries, with an emphasis on peer-reviewed studies. The conclusions from the studies are varied and imply that further research, on a case-by-case basis, is necessary before definitive conclusions can be made regarding both short- and long-term implications for state and local economies. PMID:23552649

  11. A novel high-performance liquid chromatography-electron spray ionization-mass spectrometry method for simultaneous determination of guggulsterones, piperine and gallic acid in Triphala guggulu.

    PubMed

    Muguli, Ganesh; Vadaparthi, P R Rao; Ramesh, B; Gowda, Vishakante; Paramesh, Rangesh; Jadhav, Atul N; Babu, K Suresh

    2015-05-01

    "Triphalaguggulu" is an important Ayurvedic formulation comprising of Guggulu, that is, Commiphora wightii (Arn.) Bhandari as a base wherein powdered fruits of triphala, that is, Phyllanthus emblica L., Terminalia bellirica (Gaertn.) Roxb and Terminalia chebula Retz, along with powdered fruit of Piper longum L. are compounded. This polyherbal preparation has been strongly recommended in chronic inflammation, piles, and fistula. However, due to the complexity of compound formulation standardization of commercial products is challenging. In the present communication marker-based standardization of "Triphalaguggulu" preparation using gallic acid (for triphala), piperine (for P. longum L.) and guggulsterones (for guggulu) is reported. These compounds of diverse chemistry were successfully separated on a Waters HR-C18 column by isocratic elution with methanol and water (80:20 v/v) as mobile phase at the flow rate of 1.0 mL/min coupled with photodiode array detector. These optimal chromatographic conditions were used for simultaneous quantification of gallic acid, guggulsterones (E and Z) and piperine in commercial samples by high-performance liquid chromatography-electron spray ionization-mass spectrometry and method was validated as per ICH guidelines. PMID:26109777

  12. A novel high-performance liquid chromatography-electron spray ionization-mass spectrometry method for simultaneous determination of guggulsterones, piperine and gallic acid in Triphala guggulu

    PubMed Central

    Muguli, Ganesh; Vadaparthi, P. R. Rao; Ramesh, B.; Gowda, Vishakante; Paramesh, Rangesh; Jadhav, Atul N.; Babu, K. Suresh

    2015-01-01

    “Triphalaguggulu” is an important Ayurvedic formulation comprising of Guggulu, that is, Commiphora wightii (Arn.) Bhandari as a base wherein powdered fruits of triphala, that is, Phyllanthus emblica L., Terminalia bellirica (Gaertn.) Roxb and Terminalia chebula Retz, along with powdered fruit of Piper longum L. are compounded. This polyherbal preparation has been strongly recommended in chronic inflammation, piles, and fistula. However, due to the complexity of compound formulation standardization of commercial products is challenging. In the present communication marker-based standardization of “Triphalaguggulu” preparation using gallic acid (for triphala), piperine (for P. longum L.) and guggulsterones (for guggulu) is reported. These compounds of diverse chemistry were successfully separated on a Waters HR-C18 column by isocratic elution with methanol and water (80:20 v/v) as mobile phase at the flow rate of 1.0 mL/min coupled with photodiode array detector. These optimal chromatographic conditions were used for simultaneous quantification of gallic acid, guggulsterones (E and Z) and piperine in commercial samples by high-performance liquid chromatography-electron spray ionization-mass spectrometry and method was validated as per ICH guidelines. PMID:26109777

  13. Putting downward pressure on natural gas prices: The impact of renewable energy and energy efficiency

    SciTech Connect

    Wiser, Ryan; Bolinger, Mark; St. Clair, Matthew

    2004-05-20

    Increased deployment of renewable energy (RE) and energy efficiency (EE) is expected to reduce natural gas demand and in turn place downward pressure on gas prices. A number of recent modeling studies include an evaluation of this effect. Based on data compiled from those studies summarized in this paper, each 1% reduction in national natural gas demand appears likely to lead to a long-term average wellhead gas price reduction of 0.75% to 2.5%, with some studies predicting even more sizable reductions. Reductions in wellhead prices will reduce wholesale and retail electricity rates, and will also reduce residential, commercial, and industrial gas bills. We further find that many of these studies appear to represent the potential impact of RE and EE on natural gas prices within the bounds of current knowledge, but that current knowledge of how to estimate this effect is extremely limited. While more research is therefore needed, existing studies suggest that it is not unreasonable to expect that any increase in consumer electricity costs attributable to RE and/or EE deployment may be substantially offset by the corresponding reduction in delivered natural gas prices. This effect represents a wealth transfer (from natural gas producers to consumers) rather than a net gain in social welfare, and is therefore not a standard motivation for policy intervention on economic grounds. Reducing gas prices and thereby redistributing wealth may still be of importance in policy circles, however, and may be viewed in those circles as a positive ancillary effect of RE and EE deployment.

  14. Evaluating the economic impacts of pipeline useage on the Texas oil & gas supply chain

    NASA Astrophysics Data System (ADS)

    Singh, Jashandeep

    The objective of this dissertation is to find the minimum supply chain cost for the Texas oil and gas industry, when pipeline is used as the major mode of transporting oil. The problem is solved, by introducing a mixed -- integer linear programming model which will help in taking the necessary decisions based on the cost estimates for various scenarios. In order to meet the objective, specific objectives were put down to evaluate their impacts. First was to evaluate the economic impact of mode of transport and the infrastructure second was to evaluate the economic impact of refinery flow. Finally this dissertation aims at the mixed -- integer programming model to demonstrate the economic impacts of pipeline usage on the supply chain.

  15. Quantifying habitat impacts of natural gas infrastructure to facilitate biodiversity offsetting

    PubMed Central

    Jones, Isabel L; Bull, Joseph W; Milner-Gulland, Eleanor J; Esipov, Alexander V; Suttle, Kenwyn B

    2014-01-01

    Habitat degradation through anthropogenic development is a key driver of biodiversity loss. One way to compensate losses is biodiversity offsetting (wherein biodiversity impacted is replaced through restoration elsewhere). A challenge in implementing offsets, which has received scant attention in the literature, is the accurate determination of residual biodiversity losses. We explore this challenge for offsetting gas extraction in the Ustyurt Plateau, Uzbekistan. Our goal was to determine the landscape extent of habitat impacts, particularly how the footprint of linear infrastructure (i.e. roads, pipelines), often disregarded in compensation calculations, compares with hub infrastructure (i.e. extraction facilities). We measured vegetation cover and plant species richness using the line-intercept method, along transects running from infrastructure/control sites outward for 500 m, accounting for wind direction to identify dust deposition impacts. Findings from 24 transects were extrapolated to the broader plateau by mapping total landscape infrastructure network using GPS data and satellite imagery. Vegetation cover and species richness were significantly lower at development sites than controls. These differences disappeared within 25 m of the edge of the area physically occupied by infrastructure. The current habitat footprint of gas infrastructure is 220 19 km2 across the Ustyurt (total ? 100,000 km2), 37 6% of which is linear infrastructure. Vegetation impacts diminish rapidly with increasing distance from infrastructure, and localized dust deposition does not conspicuously extend the disturbance footprint. Habitat losses from gas extraction infrastructure cover 0.2% of the study area, but this reflects directly eliminated vegetation only. Impacts upon fauna pose a more difficult determination, as these require accounting for behavioral and demographic responses to disturbance by elusive mammals, including threatened species. This study demonstrates that impacts of linear infrastructure in regions such as the Ustyurt should be accounted for not just with respect to development sites but also associated transportation and delivery routes. PMID:24455163

  16. Life-cycle energy and greenhouse gas emission impacts of different corn ethanol plant types

    NASA Astrophysics Data System (ADS)

    Wang, Michael; Wu, May; Huo, Hong

    2007-04-01

    Since the United States began a programme to develop ethanol as a transportation fuel, its use has increased from 175 million gallons in 1980 to 4.9 billion gallons in 2006. Virtually all of the ethanol used for transportation has been produced from corn. During the period of fuel ethanol growth, corn farming productivity has increased dramatically, and energy use in ethanol plants has been reduced by almost by half. The majority of corn ethanol plants are powered by natural gas. However, as natural gas prices have skyrocketed over the last several years, efforts have been made to further reduce the energy used in ethanol plants or to switch from natural gas to other fuels, such as coal and wood chips. In this paper, we examine nine corn ethanol plant typescategorized according to the type of process fuels employed, use of combined heat and power, and production of wet distiller grains and solubles. We found that these ethanol plant types can have distinctly different energy and greenhouse gas emission effects on a full fuel-cycle basis. In particular, greenhouse gas emission impacts can vary significantlyfrom a 3% increase if coal is the process fuel to a 52% reduction if wood chips are used. Our results show that, in order to achieve energy and greenhouse gas emission benefits, researchers need to closely examine and differentiate among the types of plants used to produce corn ethanol so that corn ethanol production would move towards a more sustainable path.

  17. The impact of faulting on the stability conditions of gas hydrates in Lake Baikal sediments

    NASA Astrophysics Data System (ADS)

    Golmshtok, A. Ya.

    2014-07-01

    The phase transition problem of methane hydrate in porous sediments is solved. Based on the obtained solution, the impact of faulting on the stability conditions of gas hydrates is investigated by the numerical modeling of the filtration and thermal regimes in the sedimentary cover of the Central Basin of Lake Baikal within the segment of the anomalous behavior of the bottom simulating reflector (BSR). It is assumed that such behavior is caused by the tectonic action. The calculations testify to the plausibility of the proposed model of formation of the anomalous area with total decomposition of the contained hydrates. It is shown that dissociation of gas hydrates in sediments due to faulting and the subsequent uplift of the products of these transformations along the incipient channel toward the bottom of the lake can result in the extensive accumulation of gas hydrates on this surface. It is also shown that if the total amount of the free gas, which left the hydrate dissociation zone, reached the level of the lake surface at normal pressure and temperature, its volume could be equivalent to the resources of a medium-size gas field. The results of numerical modeling the violation of the gas-hydrate stability conditions in Lake Baikal sediments can also be valid for the other regions with hydrate-bearing sediments if the case specific conditions and regional tectonic activity are taken into account.

  18. Life-cycle energy and greenhouse gas emission impacts of different corn ethanol plant types.

    SciTech Connect

    Wang, M.; Wu, M.; Huo, H.; Energy Systems

    2007-04-01

    Since the United States began a program to develop ethanol as a transportation fuel, its use has increased from 175 million gallons in 1980 to 4.9 billion gallons in 2006. Virtually all of the ethanol used for transportation has been produced from corn. During the period of fuel ethanol growth, corn farming productivity has increased dramatically, and energy use in ethanol plants has been reduced by almost by half. The majority of corn ethanol plants are powered by natural gas. However, as natural gas prices have skyrocketed over the last several years, efforts have been made to further reduce the energy used in ethanol plants or to switch from natural gas to other fuels, such as coal and wood chips. In this paper, we examine nine corn ethanol plant types--categorized according to the type of process fuels employed, use of combined heat and power, and production of wet distiller grains and solubles. We found that these ethanol plant types can have distinctly different energy and greenhouse gas emission effects on a full fuel-cycle basis. In particular, greenhouse gas emission impacts can vary significantly--from a 3% increase if coal is the process fuel to a 52% reduction if wood chips are used. Our results show that, in order to achieve energy and greenhouse gas emission benefits, researchers need to closely examine and differentiate among the types of plants used to produce corn ethanol so that corn ethanol production would move towards a more sustainable path.

  19. Gas chromatography-electron ionization mass spectrometry and liquid chromatography-electrospray tandem mass spectrometry for determination of impurities in the anti-cancer drug isophosphoramide mustard

    NASA Astrophysics Data System (ADS)

    Cole, Richard B.; Chou, Chau-Wen; Bou, Stephen M.; Leblanc, Blaise W.; Rodgers, Andrew H.; Struck, Robert F.; Morgan, Lee Roy

    2004-02-01

    Isophosphoramide mustard (IPM) is known to have substantial anti-cancer activities in various animal models. Liquid chromatography-electrospray mass spectrometry (LC-ES-MS) and LC-ES-MS/MS methodologies have been developed and applied to the analysis of synthesized preparations of IPM. Our studies reveal that the principal impurity in IPM is N-(2-chloroethyl)-N'-ethylphosphorodiamidic acid (MC-IPM) formed by dehydrochlorination of IPM with subsequent hydrogenation during synthesis. This impurity is present at levels in the range of 2-5% depending upon synthesis conditions. In addition, a second IPM derivative has been characterized by LC-ES-MS/MS and has been shown to be the product of a reaction of IPM with the dilute perchloric acid mobile phase used for liquid chromatography separations. The LC-ES-MS/MS method has been successfully employed to detect IPM spiked into a blood plasma sample. This work establishes that LC-ES-MS/MS is a viable tool for the detailed characterization of IPM and related products.

  20. Simultaneous screening for and determination of 128 date-rape drugs in urine by gas chromatography-electron ionization-mass spectrometry.

    PubMed

    Adamowicz, Piotr; Ka?a, Maria

    2010-05-20

    Date-rape drugs (DRDs) are used for the purpose of "drugging" unsuspected victims and raping or robbing them while under the influence of the drug. The wide variety of substances used for criminal purposes, their low concentrations in body fluids and, often, a long time delay between the event and clinical examination make comprehensive screening analysis of biological materials collected from crime victims for the presence of these drugs very difficult. Detection of a drug used to facilitate sexual assault in biological fluids can be very important evidence of a committed crime. The purpose of this study was to develop a simple GC-EI-MS screening procedure for date-rape drugs in urine. Target analytes were isolated by solid-phase extraction. 2-mL urine samples were extracted and then derivatized by using BSTFA+1%TMCS reagent. Detection of all compounds was based on full-scan mass spectra and for each compound one ion was chosen for further quantification. The method allowed the simultaneous screening, detection and quantification of 128 compounds from different groups (number of compounds): opioids (20), amphetamines (11), GHB and related products (3), hallucinogens (9), benzodiazepines (18), antihistamines (9), antidepressants (14), selective serotonin-reuptake inhibitors (4), antipsychotics (7), barbiturates (7), other sedatives (5), muscle relaxants (2) and other drugs (19). The procedure can easily be expanded to encompass more substances. The developed method appeared to be suitable for screening for the target DRDs. The procedure was successfully applied to the analysis of authentic urine samples collected from victims of rapes and other crimes in routine casework. PMID:20207513

  1. Miniaturized matrix solid phase dispersion procedure and solid phase microextraction for the analysis of organochlorinated pesticides and polybrominated diphenylethers in biota samples by gas chromatography electron capture detection.

    PubMed

    Moliner-Martinez, Y; Campíns-Falcó, P; Molins-Legua, C; Segovia-Martínez, L; Seco-Torrecillas, A

    2009-09-25

    This work has developed a miniaturized method based on matrix solid phase dispersion (MSPD) using C18 as dispersant and acetonitrile-water as eluting solvent for the analysis of legislated organochlorinated pesticides (OCPs) and polybrominated diphenylethers (PBDEs) in biota samples by GC with electron capture (GC-ECD). The method has compared Florisil-acidic Silica and C18 as dispersant for samples as well as different solvents. Recovery studies showed that the combination of C18-Florisil was better when using low amount of samples (0.1 g) and with low volumes of acetonitrile-water (2.6 mL). The use of SPME for extracting the analytes from the solvent mixture before the injection resulted in detection limits between 0.3 and 7.0 microg kg(-1) (expressed as wet mass). The miniaturized procedure was easier, faster, less time consuming than the conventional procedure and reduces the amounts of sample, dispersant and solvent volume by approximately 10 times. The proposed procedure was applied to analyse several biota samples from different parts of the Comunidad Valenciana. PMID:19709665

  2. Split of Gas-Liquid Two-Phase Flow at an Impacting Tee

    NASA Astrophysics Data System (ADS)

    Fujita, Isamu; Daiguji, Hirofumi; Sakai, Hitoshi; Hihara, Eiji

    Phase separation of gas-liquid two-phase flow at an impacting tee was investigated experimentally and theoretically. It was found that the phase separation did not occur, if the outlet branches were symmetrical and pressure drops in these branches were identical. On the other hand, if the flow rates in the branches were different, phase separation was observed. Based on the principle of minimum energy dissipation, a thermodynamic model was derived. The results of the model were qualitatively in good agreement with the experimental behavior of impacting flows.

  3. Statistical evaluation of the impact of shale gas activities on ozone pollution in North Texas.

    PubMed

    Ahmadi, Mahdi; John, Kuruvilla

    2015-12-01

    Over the past decade, substantial growth in shale gas exploration and production across the US has changed the country's energy outlook. Beyond its economic benefits, the negative impacts of shale gas development on air and water are less well known. In this study the relationship between shale gas activities and ground-level ozone pollution was statistically evaluated. The Dallas-Fort Worth (DFW) area in north-central Texas was selected as the study region. The Barnett Shale, which is one the most productive and fastest growing shale gas fields in the US, is located in the western half of DFW. Hourly meteorological and ozone data were acquired for fourteen years from monitoring stations established and operated by the Texas Commission on Environmental Quality (TCEQ). The area was divided into two regions, the shale gas region (SGR) and the non-shale gas (NSGR) region, according to the number of gas wells in close proximity to each monitoring site. The study period was also divided into 2000-2006 and 2007-2013 because the western half of DFW has experienced significant growth in shale gas activities since 2007. An evaluation of the raw ozone data showed that, while the overall trend in the ozone concentration was down over the entire region, the monitoring sites in the NSGR showed an additional reduction of 4% in the annual number of ozone exceedance days than those in the SGR. Directional analysis of ozone showed that the winds blowing from areas with high shale gas activities contributed to higher ozone downwind. KZ-filtering method and linear regression techniques were used to remove the effects of meteorological variations on ozone and to construct long-term and short-term meteorologically adjusted (M.A.) ozone time series. The mean value of all M.A. ozone components was 8% higher in the sites located within the SGR than in the NSGR. These findings may be useful for understanding the overall impact of shale gas activities on the local and regional ozone pollution. PMID:26232756

  4. Dust as interstellar catalyst. II. How chemical desorption impacts the gas

    NASA Astrophysics Data System (ADS)

    Cazaux, S.; Minissale, M.; Dulieu, F.; Hocuk, S.

    2016-01-01

    Context. Interstellar dust particles, which represent 1% of the total mass, are recognized to be very powerful interstellar catalysts in star-forming regions. The presence of dust can have a strong impact on the chemical composition of molecular clouds. While observations show that many species that formed onto dust grains populate the gas phase, the process that transforms solid state into gas phase remains unclear. Aims: The aim of this paper is to consider the chemical desorption process, i.e. the process that releases solid species into the gas phase, in astrochemical models. These models allow determining the chemical composition of star-forming environments with an accurate treatment of the solid-phase chemistry. Methods: In paper I we derived a formula based on experimental studies with which we quantified the efficiencies of the chemical desorption process. Here we extend these results to astrophysical conditions. Results: The simulations of astrophysical environments show that the abundances of gas-phase methanol and H2O2 increase by four orders of magnitude, whereas gas-phase H2CO and HO2 increase by one order of magnitude when the chemical desorption process is taken into account. The composition of the ices strongly varies when the chemical desorption is considered or neglected. Conclusions: We show that the chemical desorption process, which directly transforms solid species into gas-phase species, is very efficient for many reactions. Applied to astrophysical environments such as ρ Oph A, we show that the chemical desorption efficiencies derived in this study reproduce the abundances of observed gas-phase methanol, HO2, and H2O2, and that the presence of these molecules in the gas shows the last signs of the evolution of a cloud before the frost.

  5. Biocide and corrosion inhibition use in the oil and gas industry: Effectiveness and potential environmental impacts

    SciTech Connect

    Brandon, D.M.; Fillo, J.P.; Morris, A.E.; Evans, J.M.

    1995-12-01

    Treatment chemicals are used in all facets of the natural gas industry (NGI) from well development through transmission and storage of natural gas. The multitude of chemicals used, combined with the dozens of chemical manufacturers and/or suppliers has lead to the availability of hundreds of possible chemical products. Because of the widespread use of chemical products and their numerous sources, the NGI needs access to consistent data regarding their effectiveness and potential environmental impacts. The objective of this work was to evaluate the effectiveness and potential environmental impacts of, chemical products used in the NGI. This assessment was initially focused on biocides and corrosion inhibitors and their use in the gas production, storage and transmission facilities, The overall approach was obtain the necessary data on chemical use and effectiveness directly from the oil and gas industry, supplemented with data/information obtained from the published literature. Five case histories of chemical use were documented and evaluated to assess the effectiveness of these chemicals. Potential environmental impacts were addressed by performing a screening environmental assessment on the use of glutaraldehyde, a widely used biocide. Prototype discharge scenarios were formulated and modeled to evaluate potential impacts to groundwater and surface water. The paper describes the basis for the study, provides an overview of chemical use with a focus on biocides and corrosion inhibitors, describes and assesses the specific uses of chemicals, and presents the results of the environmental assessment. It was found that various chemicals can be effective in treating microbiologically influenced corrosion and souring, but that the effectiveness of specific chemicals is dependent on the operational scenario and the site-specific conditions.

  6. Gas range/oven emissions impact analysis. Final report, July 1985-December 1987

    SciTech Connect

    Tikalsky, S.; Reisdorf, K.; Flickinger, J.; Totzke, D.; Haywood, J.

    1987-12-01

    Ten older homes in Wisconsin were selected to participate in this pilot project to determine if field measurements of NO/sub 2/ and CO on gas ranges vary significantly from those reported in the literature, and if use of both vented and unvented gas appliances can be apportioned to determine separate impacts. Continuous NO/sub 2/ and CO measurements were taken in several locations within each home during two measurement periods. The project indicates that the gas oven was frequently implicated in the small group of case study homes as a source of peak hourly average NO/sub 2/ concentrations. In addition, NO/sub 2/ emission rates measured during the study were as much as a factor of two greater than those previously reported. The study also found that routine service adjustments on the ten range set resulted in statistically significant decreases in CO and NO/sub 2/ emission rates following servicing. This finding implies that some servicing of the gas range may be desirable and have an impact on indoor levels of NO/sub 2/ and CO.

  7. Impact assessment of offshore sulfur-mining subsidence on oil and gas infrastructure

    SciTech Connect

    Hunt, J.L. Jr.

    1988-01-01

    Since the Frasch process was discovered in the early 20th century and used in mining sulfur from salt dome cap rocks in coastal Louisiana and Texas, varying degrees of subsidence have been observed. Review of both historic and recent aerial photographs over certain mine sites situated in marshy coastal areas reveals substantial subsidence. Since production began in 1960 at the grand Isle Sulphur Mine located in state waters about 7 mi offshore of Grand Isle, Louisiana, approximately 70 ft of subsidence has occurred. The production platforms at the mine had to be raised or relocated due to the subsidence. No adverse impacts to existing offshore oil and gas pipelines and platforms resulting from subsidence associated with sulfur mining have been documented to date. Many of the salt domes nominated for inclusion in a sulfur and salt lease sale in federal waters offshore Louisiana, proposed for 1988, have a well-developed oil and gas infrastructure; thus the potential for subsidence-related impact does exist. Therefore, an analysis of the potential impacts to oil and gas infrastructure resulting from subsidence was done as part of the environmental assessment for the proposed lease sale.

  8. Global cropland and greenhouse gas impacts of UK food supply are increasingly located overseas.

    PubMed

    de Ruiter, Henri; Macdiarmid, Jennie I; Matthews, Robin B; Kastner, Thomas; Smith, Pete

    2016-01-01

    Producing sufficient, healthy food for a growing world population amid a changing climate is a major challenge for the twenty-first century. Agricultural trade could help alleviate this challenge by using comparative productivity advantages between countries. However, agricultural trade has implications for national food security and could displace environmental impacts from developed to developing countries. This study illustrates the global effects resulting from the agricultural trade of a single country, by analysing the global cropland and greenhouse gas impacts of the UK's food and feed supply. The global cropland footprint associated with the UK food and feed supply increased by 2022 kha (+23%) from 1986 to 2009. Greenhouse gas emissions (GHGE) associated with fertilizer and manure application, and rice cultivation remained relatively constant at 7.9 Mt CO2e between 1987 and 2008. Including GHGE from land-use change, however, leads to an increase from 19.1 in 1987 to 21.9 Mt CO2e in 2008. The UK is currently importing over 50% of its food and feed, whereas 70% and 64% of the associated cropland and GHGE impacts, respectively, are located abroad. These results imply that the UK is increasingly reliant on external resources and that the environmental impact of its food supply is increasingly displaced overseas. PMID:26740576

  9. Spatial Air Quality Impacts of Increased Natural Gas Development and Use in Texas

    NASA Astrophysics Data System (ADS)

    Allen, D.; Pacsi, A. P.

    2013-12-01

    Compared to coal-fired power plants on a per MWh basis, natural-gas electricity generators in the grid of the Electricity Reliability Council of Texas (ERCOT) emit substantially less nitrogen oxides (NOx) and sulfur dioxide (SO2), which are precursors for the formation of ozone (O3) and fine particulate matter (PM2.5). In addition, several life-cycle assessments have concluded that the development and use of shale gas resources will likely lead to air quality benefits, despite emissions associated with natural gas production, due to changes in fuel utilization in the electricity generation sector. The formation of ozone and PM2.5 is non-linear, however, and depends on spatial and temporal patterns associated with the precursor emissions. This study used Texas as a case-study for the changes in regional ozone and PM2.5 concentrations associated with natural gas production and use in electricity generation in the state. Texas makes a compelling case study since it was among the first states with large-scale shale gas production with horizontal drilling and hydraulic fracturing technologies, since it has a self-contained electric grid (ERCOT), and since it includes several regions which do not currently meet Federal standards for ozone. This study utilized an optimal power flow model for electricity generation in ERCOT, coupled with a regional photochemical model to estimate the ozone and PM2.5 impacts of changes to natural gas production and use in the state. The utilization of natural gas is highly dependent on the relative price of natural gas compared to coal. Thus, the amount of natural gas consumed in power generation in ERCOT was estimated for a range of prices from 1.89-7.74, which have occurred in Texas since 2006. Sensitivity scenarios in which natural gas production emissions in the Barnett Shale were raised or lowered depending on demand for the fuel in the electricity generation sector were also examined. Overall results indicate that regional ozone and fine PM2.5 concentrations are reduced as the price of natural gas decreased in Texas. The air quality impacts were predominantly driven by changes in the electricity generation sector rather than in the fuel-supply chain. The areas in which the largest changes in ozone and fine PM were modeled were regions with several coal-fired power plants, which were dispatched less frequently in our model as the price of natural gas decreased. Ozone decreases were largest in magnitude in the afternoon hours during times which were relevant for the daily maximum 8-hour ozone concentration, on which the Federal ozone standard is based. Despite localized increases in NOx and volatile organic compound (VOC) emissions associated with the natural gas production in the Barnett Shale, ozone concentrations were modeled to decrease in the region with decreasing natural gas prices.

  10. EMBRYO IMPACTS AND GAS GIANT MERGERS. I. DICHOTOMY OF JUPITER AND SATURN's CORE MASS

    SciTech Connect

    Li Shulin; Agnor, C.B.; Lin, D. N. C.

    2010-09-10

    Interior to the gaseous envelopes of Saturn, Uranus, and Neptune, there are high-density cores with masses larger than 10 Earth masses. According to the conventional sequential accretion hypothesis, such massive cores are needed for the onset of efficient accretion of their gaseous envelopes. However, Jupiter's gaseous envelope is more massive and its core may be less massive than those of Saturn. In order to account for this structural diversity and the super-solar metallicity in the envelope of Jupiter and Saturn, we investigate the possibility that they may have either merged with other gas giants or consumed several Earth-mass protoplanetary embryos during or after the rapid accretion of their envelope. In general, impinging sub-Earth-mass planetesimals disintegrate in gas giants' envelopes, deposit heavy elements well outside the cores, and locally suppress the convection. Consequently, their fragments sediment to promote the growth of cores. Through a series of numerical simulations, we show that it is possible for colliding super-Earth-mass embryos to reach the cores of gas giants. Direct parabolic collisions also lead to the coalescence of gas giants and merging of their cores. In these cases, the energy released from the impact leads to vigorous convective motion throughout the envelope and the erosion of the cores. This dichotomy contributes to the observed dispersion in the internal structure and atmospheric composition between Jupiter and Saturn and other gas giant planets and elsewhere.

  11. Evaluating the impact of gas extraction infrastructure on the occupancy of sagebrush-obligate songbirds.

    PubMed

    Mutter, Max; Pavlacky, David C; Van Lanen, Nicholas J; Grenyer, Richard

    2015-07-01

    Development associated with natural gas extraction may have negative effects on wildlife. Here we assessed the effects of natural gas development on the distributions of three sagebrush-obligate birds (Brewer's Sparrow, Spizella breweri; Sagebrush Sparrow, Amphispiza belli; and Sage Thrasher, Oreoscoptes montanus) at a natural gas extraction site in Wyoming, USA. Two drivers of habitat disturbance were investigated: natural gas well pads and roadways. Disturbances were quantified on a small scale (minimum distance to a disturbance) and a large scale (landscape density of a disturbance). Their effects on the study species' distributions were assessed using a multi-scale occupancy model. Minimum distances to wells and roadways were found to not have significant impacts on small-scale occupancy. However, roadway and well density at the landscape-scale significantly impacted the large-scale occupancy of Sagebrush Sparrows and Sage Thrashers. The results confirmed our hypotheses that increasing road density negatively affects the landscape-scale occupancy rates of Sagebrush Sparrow and Sage Thrasher, but did not confirm our hypothesis that increasing well density would negatively impact large-scale occupancy. We therefore suggest that linear features that affect patch size may be more important than point features in determining sagebrush-obligate songbird occupancy when compared to structural effects such as habitat fragmentation and increased predation. We recommend that future well construction be focused along existing roadways, that horizontal drilling be used to reduce the need for additional roads, and that deactivation and restoration of roadways be implemented upon the deactivation of wells, we also recommend a possible mitigation strategy when new roads are to be built. PMID:26485947

  12. Estimating the Impact of US Agriculture Subsidies on Greenhouse Gas Emissions

    NASA Astrophysics Data System (ADS)

    Eshel, G.; Martin, P. A.

    2006-12-01

    It has been proposed in the popular media that US agricultural subsidies contribute deleteriously to both the American diet and environment. In this view, subsidies render mostly corn-based, animal products and sweeteners artificically cheap, leading to enhanced consumption. Problems accompanying this structure mentioned include enhanced meat, fat and sugar consumption and the associated enhancement of obesity, cardiovascular diseases, type II diabetes and possible various types of cancer, as well as air, soil and water pollution. Often overlooked in these discussions is the potential enhancement of greenhouse gas emissions accompanying this policy-based steering of food consumption toward certain products at the expense of others, possibly more nutritionally and environmentally benign. If such enhancements are in fact borne out by data, the policies that give rise to them will prove to constitute government-sponsored enhancement of greenhouse gas emissions, in contrast to any climate change mitigation efforts. If so, they represent low- hanging fruits in the national effort to reduce greenhouse gas emissions which may one day be launched. Agriculture subsidies impact the emissions of CO2 (by direct energy consumption), nitrous oxide (by land use alteration and manure management), and methane (by ruminant digestion and manure treatment). Quantifying the impacts of agricultural subsidies is complicated by many compounding and conflicting effects (many related to human behavior rather than the natural sciences) and the relatively short data timeseries. For example, subsidy policies change over time, certain subsidy types are introduced or eliminated, food preferences change as nutritional understanding (or propaganda) shift, etc. Despite the difficulties, such quantification is crucial to better estimate the overall effect and variability of dietary choices on greenhouse gas emissions, and ultimately minimize environmental impacts. In this study, we take preliminary steps toward this challenging quantification. We calculate the added consumption of meat and corn-based sweeteners that can be readily attributable to subsidies. We conclude by using traditional, non-controversial conversion factors to express these enhancements in terms of tons of CO2-equivalent.

  13. Impacts of natural gas mining on regional methane levels in Pennsylvania

    NASA Astrophysics Data System (ADS)

    Lembeck-Edens, A. M.; Fuentes, J. D.; Martins, D. K.; Grannas, A. M.

    2013-12-01

    Increased natural gas exploration has been hypothesized to be a strong source of atmospheric methane, leading to enhanced regional methane levels. Fugitive methane emissions can result from leaky natural gas wells and pipelines. Pennsylvania is experiencing rapid natural gas well development and operation. In the Pennsylvania Marcellus Shale region, the density of natural gas wells is increasing. Therefore, a field study took place during 8 June to 6 August 2013 to investigate the magnitude of fugitive methane emissions near well sites and along established pipelines, as well as the spatial distribution of methane throughout Pennsylvania. The necessary instruments were mounted on a mobile platform (six-passenger van) to make transects running from southwestern to northeastern Pennsylvania where the highest density of wells is already established. Methane and carbon dioxide mixing ratios and their respective 13C isotopes were detected using a cavity ring-down spectrometer while the van was moving along pipelines or near natural gas well sites. Air sampling was done in areas away from natural well sites to establish the baseline of methane levels in the rural atmosphere. Also, air sampling took place around barns to distinguish the contribution of cattle to the atmospheric loading of methane. In the rural atmosphere, away from natural gas wells, methane levels remained around (baseline) 1.75 parts per millions (ppm). Methane levels in areas impacted by natural gas wells were higher than the baseline. Along pipelines, methane levels ranged from baseline levels of 1.75 ppm to 5.00 ppm. Near wells, plumes of methane-enriched air reached as high as 15.30 ppm. Although leaks from wells have been noted in previous studies, this investigation suggested that wells intermittently leaked methane. The main conclusion from the present study is that fugitive emissions from natural gas wells and pipelines contribute to enhancing the regional methane levels during daytime conditions, up to an average mixing ratio of 1.95 ppm. Along with ancillary data, we will present and discuss the implications of the results in the context of greenhouse effect forcing and regional air quality impacts.

  14. User-Friendly Tool to Calculate Economic Impacts from Coal, Natural Gas, and Wind: The Expanded Jobs and Economic Development Impact Model (JEDI II); Preprint

    SciTech Connect

    Tegen, S.; Goldberg, M.; Milligan, M.

    2006-06-01

    In this paper we examine the impacts of building new coal, gas, or wind plants in three states: Colorado, Michigan, and Virginia. Our findings indicate that local/state economic impacts are directly related to the availability and utilization of local industries and services to build and operate the power plant. For gas and coal plants, the economic benefit depends significantly on whether the fuel is obtained from within the state, out of state, or some combination. We also find that the taxes generated by power plants can have a significant impact on local economies via increased expenditures on public goods.

  15. Ozone Air Quality Impacts of Shale Gas Development in South Texas Urban Areas

    NASA Astrophysics Data System (ADS)

    Chang, C.; Liao, K.

    2013-12-01

    Recent technological advances, mainly horizontal drilling and hydraulic fracturing, and continued drilling in shale, have increased domestic production of oil and gas in the United State (U.S.). However, shale gas developments could also affect the environment and human health, particularly in areas where oil and gas developments are new activities. This study is focused on the impacts of shale gas developing activities on summertime ozone air quality in South Texas urban areas since many of them are already ozone nonattainment areas. We use an integrated approach to investigate the ozone air quality impact of the shale gas development in South Texas urban areas. They are: (1) satellite measurement of precursors, (2) observations of ground-level ozone concentrations, and (3) air mass trajectory modeling. Nitrogen dioxide (NO2) is an important precursor to ozone formation, and summertime average tropospheric nitrogen dioxide (NO2) column densities measured by the National Aeronautics and Space Administration's Ozone Monitoring Instrument increased in the South Texas shale area (i.e., the Eagle Ford Shale area) in 2011 and 2012 as compared to 2008-2010. The U.S. Environmental Protection Agency's ground-level observations showed summertime average and peak ozone (i.e., the 4th highest daily maximum 8-hour average ozone) concentrations slightly increased from 2010 to 2012 in Austin and San Antonio. However, the frequencies of peak ozone concentrations above the 75ppb ozone standard have been significantly increasing since 2011 in Austin and San Antonio. It is expected to increase the possibilities of violating the ozone National Ambient Air Quality Standard (NAAQS) for South Texas urban areas in the future. The results of trajectory modeling showed air masses transported from the southeastern Texas could reach Austin and San Antonio and confirmed that emissions from the Eagle Ford Shale area could affect ozone air quality in South Texas urban areas in 2011 and 2012. Overall, emissions associated with shale gas activities in South Texas have been affecting ozone air quality in neighboring urban areas. Developing effective control strategies for reducing emissions from shale gas activities and improving ozone air quality is an important issue in Texas and other states in the U.S..Changes in percentage of summertime 4th highest ozone daily maximum as comparing to previous year

  16. Potential impacts of the Energy Policy Act on electricity and natural gas provider fleets

    SciTech Connect

    Vyas, A.D.; Wang, M.Q.

    1996-03-01

    Section 501 of the 1992 Energy Policy and Conservation Act (EPACT) mandates that alternative-fuel providers who may sell such fuels for transportation uses acquire alternative-fuel vehicles (AFVs). The potential impacts of this mandate on the two largest groups of alternative-fuel providers--electricity and natural gas (NG) providers--are presented. Nationwide, 166 electric-only utility companies, 127 NG-only utility companies, and 55 dual-utility companies will be covered by EPACT. Together, these companies own/operate nearly 122,000 light-duty vehicles in the EPACT-defined metropolitan areas. Some 63 natural gas producers and transporters, which have 9700 light-duty vehicles, are also covered. We project that covered fuel providers will purchase 2710 AFVs in 1996 and 13, 650 AFVs by 2001. We estimate that natural gas companies already have 19.4% of their existing light-duty vehicle stocks as AFVs, dual companies have 10.0%, natural gas producers and transporters have 7. 0%, and electric companies have only 1.6%. If the existing AFVs count toward meeting the Section 501 requirements, NG providers (NG utilities, dual utilities, and NG producers and transporters) will need to make little additional effort, but electric companies will have to make substantial commitments to meet the requirements.

  17. Acute health impact of the gas release at Lake Nyos, Cameroon, 1986

    NASA Astrophysics Data System (ADS)

    Baxter, Peter J.; Kapila, Mukesh

    1989-11-01

    Available medical evidence on the acute health impact of the gas release at Lake Nyos is summarised, including the results of a survey of medical records of 845 survivors treated at Wum and Nkambe hospitals. The main clinical features were compatible with exposure to an asphyxiant gas such as CO 2 but confirmation of the identity of the gas or gases involved was not possible. Exposure to CO 2 over such a large inhabited area and reversible coma lasting for hours after CO 2 gassing do not appear to have been reported before. In some victims, blistering or ulceration of the skin was present which could not be readily explained by local injury from pressure, or burns from acid, or falling near fires. Further epidemiological studies on survivors are unlikely to be feasible, but the possibility of long-term anoxic brain damage among adults and children who had been rendered comatose by the gas should be considered, though overt evidence of major neurological or respiratory disability was not apparent in survivors in the weeks following the disaster. The inadequacy of the toxicological and forensic evidence obtained points to the need for the rapid mobilisation of medical scientists in future disasters of this kind.

  18. Impact of gas bremsstrahlung on synchrotron radiation beamline shielding at the Advanced Photon Source

    SciTech Connect

    Ipe, N.E.; Fasso, A.

    1994-01-01

    The Advanced Photon Source (APS) currently under construction at Argonne National Laboratory will be one of the world`s brightest synchrotron radiation facilities. The storage ring, capable of storing currents up to 300 mA at 7.0 GeV and 200 mA at 7.5 GeV, will produce very intense and energetic synchrotron radiation (E{sub c} = 24 keV for bending magnets and E{sub c} = 37.4 keV for wigglers, where E{sub c} is the critical energy). The synchrotron radiation (SR) beam lines consisting of experimental enclosures and transport lines will have to be shielded against synchrotron radiation and gas bremsstrahlung scattered from beam line components. For insertion devices placed in the straight sections (length = 15 m), the gas bremsstrahlung produced by the interaction of the primary stored beam with residual gas molecules or ions in the storage ring vacuum chamber dominates the SR beam line shielding. The impact of gas bremsstrahlung on the SR beam line shielding is discussed in this paper.

  19. Impact of natural gas extraction on PAH levels in ambient air.

    PubMed

    Paulik, L Blair; Donald, Carey E; Smith, Brian W; Tidwell, Lane G; Hobbie, Kevin A; Kincl, Laurel; Haynes, Erin N; Anderson, Kim A

    2015-04-21

    Natural gas extraction, often referred to as "fracking," has increased rapidly in the U.S. in recent years. To address potential health impacts, passive air samplers were deployed in a rural community heavily affected by the natural gas boom. Samplers were analyzed for 62 polycyclic aromatic hydrocarbons (PAHs). Results were grouped based on distance from each sampler to the nearest active well. PAH levels were highest when samplers were closest to active wells. Additionally, PAH levels closest to natural gas activity were an order of magnitude higher than levels previously reported in rural areas. Sourcing ratios indicate that PAHs were predominantly petrogenic, suggesting that elevated PAH levels were influenced by direct releases from the earth. Quantitative human health risk assessment estimated the excess lifetime cancer risks associated with exposure to the measured PAHs. Closest to active wells, the risk estimated for maximum residential exposure was 2.9 in 10 000, which is above the U.S. EPA's acceptable risk level. Overall, risk estimates decreased 30% when comparing results from samplers closest to active wells to those farthest. This work suggests that natural gas extraction may be contributing significantly to PAHs in air, at levels that are relevant to human health. PMID:25810398

  20. Federal Clean Water Act legislative and regulatory developments impacting the oil and gas industry

    SciTech Connect

    Lesniak, K.Z.

    1995-12-31

    Although the 103rd Congress made substantial progress towards passage of Clean Water Act amendments and reauthorization legislation and other environmental bills, including Safe Drinking Water Act reauthorization, 1994 resulted in no substantial new environmental legislation. Regulatory developments proceeded slowly as well, the most significant water regulatory issues on the federal level potentially impacting oil and gas operations being the anticipated issuance of a multi-sector storm water general permit and continuing EPA study of effluent limitations for coastal oil and gas extraction. The several Oil Pollution Act regulatory developments over the last year, including vessel financial responsibility, oil spill response planning, and revisions to the National Contingency Plan are not addressed in this paper.

  1. Flowing Gas in Mass Spectrometer: Method for Characterization and Impact on Ion Processing

    PubMed Central

    Zhou, Xiaoyu; Ouyang, Zheng

    2014-01-01

    Mass spectrometers are complex instrumentation systems with ions transferred though different pressure regions and mass analyzed at high vacuum. In this work, we have investigated the impacts of the gas flows that exit almost universally in all pressure regions and developed a method incorporating the dynamic gas field with the electric (E) field in the simulation of ion trajectories. The capability of the electro-hydrodynamic simulation (EHS) method was demonstrated for characterizing the ion optical systems in atmospheric pressure interfaces. With experimental validation, the trapping of the externally-injected ions in a linear ion trap at low pressure has also been studied. Further development of the EHS method and the knowledge acquired in this research are expected to be useful in the design of hybrid instruments and study of ion energetics. PMID:25121805

  2. Evaluating natural gas development impacts on stream ecosystems in an Upper Colorado River watershed

    NASA Astrophysics Data System (ADS)

    Holloway, J. M.; Bern, C.; Schmidt, T. S.; McDougal, R. R.; Clark, M. L.; Stricker, C. A.; Wolf, R. E.

    2011-12-01

    Oil and gas development in the western United States is increasingly placing at odds the management of two critical natural resources: fossil fuels and water. Muddy Creek, part of the Upper Colorado River watershed, is a semi-arid catchment in a sagebrush steppe ecosystem. Muddy Creek flows throughout the year and includes both perennial and ephemeral tributaries. Primary land use includes livestock grazing, oil and gas development, and recreational activities. A multi-discipline study has been initiated to determine potential impacts of the projected increase of coal bed natural gas development. Hundreds of permits for drilling co-produced waters have been issued, but low energy prices have slowed development. A watershed assessment was conducted in 2010 to determine areas within the watershed that are more susceptible to mobilization of trace elements that occur in soils forming on marine shales. Soil, stream sediment, and water samples were collected and analyzed for major elements and a suite of trace elements, with arsenic and selenium identified as potential elements of concern. A study of benthic and riparian invertebrates is being conducted to evaluate the uptake of these elements into the food web at targeted locations in the Muddy Creek watershed. Continued work will address sources of salinity to Muddy Creek, and ultimately to the Upper Colorado River. Impacts from energy development can include mobilization of naturally occurring sulfate salts through soil disturbance. Formation waters currently discharged to the surface from two failed wells within the watershed will be evaluated for their contribution to salinity, as well as dissolved organic carbon, nitrogen species, and trace elements, to the Upper Colorado River. Upon completion, this study will provide a baseline that can assist in land-use management decisions as oil and gas extraction expands in the Upper Colorado River watershed.

  3. Regional impacts of oil and gas development on ozone formation in the western United States.

    PubMed

    Rodriguez, Marco A; Barna, Michael G; Moore, Tom

    2009-09-01

    The Intermountain West is currently experiencing increased growth in oil and gas production, which has the potential to affect the visibility and air quality of various Class I areas in the region. The following work presents an analysis of these impacts using the Comprehensive Air Quality Model with extensions (CAMx). CAMx is a state-of-the-science, "one-atmosphere" Eulerian photochemical dispersion model that has been widely used in the assessment of gaseous and particulate air pollution (ozone, fine [PM2.5], and coarse [PM10] particulate matter). Meteorology and emissions inventories developed by the Western Regional Air Partnership Regional Modeling Center for regional haze analysis and planning are used to establish an ozone baseline simulation for the year 2002. The predicted range of values for ozone in the national parks and other Class I areas in the western United States is then evaluated with available observations from the Clean Air Status and Trends Network (CASTNET). This evaluation demonstrates the model's suitability for subsequent planning, sensitivity, and emissions control strategy modeling. Once the ozone baseline simulation has been established, an analysis of the model results is performed to investigate the regional impacts of oil and gas development on the ozone concentrations that affect the air quality of Class I areas. Results indicate that the maximum 8-hr ozone enhancement from oil and gas (9.6 parts per billion [ppb]) could affect southwestern Colorado and northwestern New Mexico. Class I areas in this region that are likely to be impacted by increased ozone include Mesa Verde National Park and Weminuche Wilderness Area in Colorado and San Pedro Parks Wilderness Area, Bandelier Wilderness Area, Pecos Wilderness Area, and Wheeler Peak Wilderness Area in New Mexico. PMID:19785277

  4. Safety analysis report for packaging: the ORNL gas-cylinder fire and impact shield

    SciTech Connect

    Evans, J.H.; Levine, D.L.; Eversole, R.E.; Mouring, R.W.

    1983-04-01

    The ORNL gas-cylinder fire and impact shield was designed and fabricated at the Oak Ridge Gaseous Diffusion Plant for the transport of cylinders filled with radioactive gases. The shield was evaluated analytically and experimentally to determine its compliance with the applicable regulations governing containers in which radioactive and fissile materials are transported, and the results are reported herein. Computational and test procedures were used to determine the structural integrity and thermal behavior of the cask relative to the general standards for normal conditions of transport and the standards for hypothetical accident conditions. Results of the evaluation demonstrate that the container is in compliance with the applicable regulations.

  5. Electron-Impact Excitation Cross Sections for Modeling Non-Equilibrium Gas

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.; Liu, Yen; Panesi, Marco; Munafo, Alessandro; Wray, Alan; Carbon, Duane F.

    2015-01-01

    In order to provide a database for modeling hypersonic entry in a partially ionized gas under non-equilibrium, the electron-impact excitation cross sections of atoms have been calculated using perturbation theory. The energy levels covered in the calculation are retrieved from the level list in the HyperRad code. The downstream flow-field is determined by solving a set of continuity equations for each component. The individual structure of each energy level is included. These equations are then complemented by the Euler system of equations. Finally, the radiation field is modeled by solving the radiative transfer equation.

  6. A Gas-Actuated Projectile Launcher for High-Energy Impact Testing of Structures

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R.; Jaunky, Navin; Lawson, Robin E.; Knight, Norman F., Jr.; Lyle, Karen H.

    1999-01-01

    A gas-act,uated penetration device has been developed for high-energy impact testing of structures. The high-energy impact. t,estiiig is for experimental simulation of uncontained engine failures. The non-linear transient finite element, code LS-DYNA3D has been used in the numerical simula.tions of a titanium rectangular blade with a.n aluminum target, plate. Threshold velocities for different combinations of pitch and yaw angles of the impactor were obtained for the impactor-target, t8est configuration in the numerica.1 simulations. Complet,e penet,ration of the target plate was also simulat,ed numerically. Finally, limited comparison of analytical and experimental results is presented for complete penetration of the target by the impactor.

  7. Application of the screening potential approach for Electron Impact ionization of rare-gas atoms

    NASA Astrophysics Data System (ADS)

    Saha, Hari

    2013-05-01

    The triple differential cross section for electron impact ionization of rare-gas atoms will be investigated using our recently extended MCHF method. It is well known electron correlation effects in both the initial and the final states are very important. To incorporate these effects we will use the multi-configuration Hartree-Fock method to account for electron correlation in the initial state. The electron correlation in the final state will be taken into account using the angle-dependent screening potential approximation. As a test case, the triple differential cross section (TDCS) will be calculated for electron impact ionization of Argon atom, which has experimental results. Our results will be compared with available experimental and the theoretical observations.

  8. Structural Integrity of Gas-Filled Composite Overwrapped Pressure Vessels Subjected to Orbital Debris Impact

    NASA Astrophysics Data System (ADS)

    Telichev, Igor; Cherniaev, Aleksandr

    Gas-filled pressure vessels are extensively used in spacecraft onboard systems. During operation on the orbit they exposed to the space debris environment. Due to high energies they contain, pressure vessels have been recognized as the most critical spacecraft components requiring protection from orbital debris impact. Major type of pressurized containers currently used in spacecraft onboard systems is composite overwrapped pressure vessels (COPVs) manufactured by filament winding. In the present work we analyze the structural integrity of vessels of this kind in case of orbital debris impact at velocities ranging from 2 to 10 km/s. Influence of such parameters as projectile energy, shielding standoff, internal pressure and filament winding pattern on COPVs structural integrity has been investigated by means of numerical and physical experiments.

  9. Calculation of Ground State Rotational Populations for Kinetic Gas Homonuclear Diatomic Molecules including Electron-Impact Excitation and Wall Collisions

    SciTech Connect

    David R. Farley

    2010-08-19

    A model has been developed to calculate the ground-state rotational populations of homonuclear diatomic molecules in kinetic gases, including the effects of electron-impact excitation, wall collisions, and gas feed rate. The equations are exact within the accuracy of the cross sections used and of the assumed equilibrating effect of wall collisions. It is found that the inflow of feed gas and equilibrating wall collisions can significantly affect the rotational distribution in competition with non-equilibrating electron-impact effects. The resulting steady-state rotational distributions are generally Boltzmann for N≥3, with a rotational temperature between the wall and feed gas temperatures. The N=0,1,2 rotational level populations depend sensitively on the relative rates of electron-impact excitation versus wall collision and gas feed rates.

  10. Calculation of ground state rotational populations for kinetic gas homonuclear diatomic molecules including electron-impact excitation and wall collisions

    NASA Astrophysics Data System (ADS)

    Farley, David R.

    2010-09-01

    A model has been developed to calculate the ground state rotational populations of homonuclear diatomic molecules in kinetic gases, including the effects of electron-impact excitation, wall collisions, and gas feed rate. The equations are exact within the accuracy of the cross sections used and of the assumed equilibrating effect of wall collisions. It is found that the inflow of feed gas and equilibrating wall collisions can significantly affect the rotational distribution in competition with nonequilibrating electron-impact effects. The resulting steady-state rotational distributions are generally Boltzmann for N ≥3, with a rotational temperature between the wall and feed gas temperatures. The N =0,1,2 rotational level populations depend sensitively on the relative rates of electron-impact excitation versus wall collision and gas feed rates.

  11. Calculation of ground state rotational populations for kinetic gas homonuclear diatomic molecules including electron-impact excitation and wall collisions.

    PubMed

    Farley, David R

    2010-09-01

    A model has been developed to calculate the ground state rotational populations of homonuclear diatomic molecules in kinetic gases, including the effects of electron-impact excitation, wall collisions, and gas feed rate. The equations are exact within the accuracy of the cross sections used and of the assumed equilibrating effect of wall collisions. It is found that the inflow of feed gas and equilibrating wall collisions can significantly affect the rotational distribution in competition with nonequilibrating electron-impact effects. The resulting steady-state rotational distributions are generally Boltzmann for N≥3, with a rotational temperature between the wall and feed gas temperatures. The N=0,1,2 rotational level populations depend sensitively on the relative rates of electron-impact excitation versus wall collision and gas feed rates. PMID:20831314

  12. Natural gas and CO2 price variation: impact on the relative cost-efficiency of LNG and pipelines.

    PubMed

    Ulvestad, Marte; Overland, Indra

    2012-06-01

    THIS ARTICLE DEVELOPS A FORMAL MODEL FOR COMPARING THE COST STRUCTURE OF THE TWO MAIN TRANSPORT OPTIONS FOR NATURAL GAS: liquefied natural gas (LNG) and pipelines. In particular, it evaluates how variations in the prices of natural gas and greenhouse gas emissions affect the relative cost-efficiency of these two options. Natural gas is often promoted as the most environmentally friendly of all fossil fuels, and LNG as a modern and efficient way of transporting it. Some research has been carried out into the local environmental impact of LNG facilities, but almost none into aspects related to climate change. This paper concludes that at current price levels for natural gas and CO2 emissions the distance from field to consumer and the volume of natural gas transported are the main determinants of transport costs. The pricing of natural gas and greenhouse emissions influence the relative cost-efficiency of LNG and pipeline transport, but only to a limited degree at current price levels. Because more energy is required for the LNG process (especially for fuelling the liquefaction process) than for pipelines at distances below 9100 km, LNG is more exposed to variability in the price of natural gas and greenhouse gas emissions up to this distance. If the prices of natural gas and/or greenhouse gas emission rise dramatically in the future, this will affect the choice between pipelines and LNG. Such a price increase will be favourable for pipelines relative to LNG. PMID:24683269

  13. Natural gas and CO2 price variation: impact on the relative cost-efficiency of LNG and pipelines

    PubMed Central

    Ulvestad, Marte; Overland, Indra

    2012-01-01

    This article develops a formal model for comparing the cost structure of the two main transport options for natural gas: liquefied natural gas (LNG) and pipelines. In particular, it evaluates how variations in the prices of natural gas and greenhouse gas emissions affect the relative cost-efficiency of these two options. Natural gas is often promoted as the most environmentally friendly of all fossil fuels, and LNG as a modern and efficient way of transporting it. Some research has been carried out into the local environmental impact of LNG facilities, but almost none into aspects related to climate change. This paper concludes that at current price levels for natural gas and CO2 emissions the distance from field to consumer and the volume of natural gas transported are the main determinants of transport costs. The pricing of natural gas and greenhouse emissions influence the relative cost-efficiency of LNG and pipeline transport, but only to a limited degree at current price levels. Because more energy is required for the LNG process (especially for fuelling the liquefaction process) than for pipelines at distances below 9100 km, LNG is more exposed to variability in the price of natural gas and greenhouse gas emissions up to this distance. If the prices of natural gas and/or greenhouse gas emission rise dramatically in the future, this will affect the choice between pipelines and LNG. Such a price increase will be favourable for pipelines relative to LNG. PMID:24683269

  14. Scoping Study on the Safety Impact of Valve Spacing in Natural Gas Pipelines

    SciTech Connect

    Sulfredge, Charles David

    2007-07-01

    The U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA) is responsible for ensuring the safe, reliable, and environmentally sound operation of the nation's natural gas and hazardous liquid pipelines. Regulations adopted by PHMSA for gas pipelines are provided in 49 CFR 192, and spacing requirements for valves in gas transmission pipelines are presented in 49 CFR 192.179. The present report describes the findings of a scoping study conducted by Oak Ridge National Laboratory (ORNL) to assist PHMSA in assessing the safety impact of system valve spacing. Calculations of the pressures, temperatures, and flow velocities during a set of representative pipe depressurization transients were carried out using a one-dimensional numerical model with either ideal gas or real gas properties for the fluid. With both ideal gas and real gas properties, the high-consequence area radius for any resulting fire as defined by Stevens in GRI-00/0189 was evaluated as one measure of the pipeline safety. In the real gas case, a model for convective heat transfer from the pipe wall is included to assess the potential for shut-off valve failures due to excessively low temperatures resulting from depressurization cooling of the pipe. A discussion is also provided of some additional factors by which system valve spacing could affect overall pipeline safety. The following conclusions can be drawn from this work: (1) Using an adaptation of the Stephens hazard radius criteria, valve spacing has a negligible influence on natural gas pipeline safety for the pipeline diameter, pressure range, and valve spacings considered in this study. (2) Over the first 30 s of the transient, pipeline pressure has a far greater effect on the hazard radius calculated with the Stephens criteria than any variations in the transient flow decay profile and the average discharge rate. (3) Other factors besides the Stephens criteria, such as the longer burn time for an accidental fire, greater period of danger to emergency personnel, increased unavoidable loss of gas, and possible depressurization cooling of the shut-off valves may also be important when deciding whether a change in the required valve spacing would be beneficial from a safety standpoint. (4) The average normalized discharge rate of {lambda}{sub avg} = 0.33 assumed by Stephens in developing his safety criteria is an excellent conservative value for natural gas discharge at the pressures, valve spacings, and pipe diameter used in this study. This conclusion remains valid even when real rather than ideal gas properties are considered in the analysis. (5) Significant pipe wall cooling effects (T{sub w} < -50 F or 228 K) can extend for a mile or more upstream from the rupture point within 30 s of a break. These conditions are colder than the temperature range specifications for many valve lubricants. The length of the low-temperature zone due to this cooling effect is also essentially independent of the system shut-off valve spacing or the distance between the break and a compressor station. (6) Having more redundant shut-off valves available would reduce the probability that pipe cooling effects could interfere with isolating the broken area following a pipeline rupture accident.

  15. Regional variation in water-related impacts of shale gas development and implications for emerging international plays.

    PubMed

    Mauter, Meagan S; Alvarez, Pedro J J; Burton, Allen; Cafaro, Diego C; Chen, Wei; Gregory, Kelvin B; Jiang, Guibin; Li, Qilin; Pittock, Jamie; Reible, Danny; Schnoor, Jerald L

    2014-01-01

    The unconventional fossil fuel industry is expected to expand dramatically in coming decades as conventional reserves wane. Minimizing the environmental impacts of this energy transition requires a contextualized understanding of the unique regional issues that shale gas development poses. This manuscript highlights the variation in regional water issues associated with shale gas development in the U.S. and the approaches of various states in mitigating these impacts. The manuscript also explores opportunities for emerging international shale plays to leverage the diverse experiences of U.S. states in formulating development strategies that minimize water-related impacts within their environmental, cultural, and political ecosystem. PMID:24684515

  16. BAG: A code for predicting the performance of a gas bag impact attenuation system for the PATHFINDER lander

    SciTech Connect

    Cole, J.K.; Waye, D.E.

    1993-11-01

    The National Aeronautics and Space Administration (NASA) is planning to launch a network of scientific probes to Mars beginning in late 1996. The precursor to this network will be PATHFINDER. Decelerating PATHFINDER from the high speed of its approach to Mars will require the use of several deceleration techniques working in series. The Jet Propulsion Laboratory (JPL) has proposed that gas bags be used to cushion the payload`s ground impact on Mars. This report presents the computer code, BAG, which has been developed to calculate the pneumatic performance of gas bag impact attenuators and the one-dimensional rigid-body dynamic performance of a payload during ground impact.

  17. Climate change impacts and greenhouse gas mitigation effects on U.S. water quality

    NASA Astrophysics Data System (ADS)

    Boehlert, Brent; Strzepek, Kenneth M.; Chapra, Steven C.; Fant, Charles; Gebretsadik, Yohannes; Lickley, Megan; Swanson, Richard; McCluskey, Alyssa; Neumann, James E.; Martinich, Jeremy

    2015-09-01

    Climate change will have potentially significant effects on freshwater quality due to increases in river and lake temperatures, changes in the magnitude and seasonality of river runoff, and more frequent and severe extreme events. These physical impacts will in turn have economic consequences through effects on riparian development, river and reservoir recreation, water treatment, harmful aquatic blooms, and a range of other sectors. In this paper, we analyze the physical and economic effects of changes in freshwater quality across the contiguous U.S. in futures with and without global-scale greenhouse gas mitigation. Using a water allocation and quality model of 2119 river basins, we estimate the impacts of various projected emissions outcomes on several key water quality indicators, and monetize these impacts with a water quality index approach. Under mitigation, we find that water temperatures decrease considerably and that dissolved oxygen levels rise in response. We find that the annual economic impacts on water quality of a high emissions scenario rise from 1.4 billion in 2050 to 4 billion in 2100, leading to present value mitigation benefits, discounted at 3%, of approximately $17.5 billion over the 2015-2100 period.

  18. Advanced diagnostics for impact-flash spectroscopy on light-gas guns.

    SciTech Connect

    Breiland, William George; Reinhart, William Dodd; Miller, Paul Albert; Brown, Justin L.; Thornhill, Tom Finley, III; Mangan, Michael A.; Shaner, Eric Arthur; Chhabildas, Lalit Chandra; Grine, Albert D.; Wanke, Michael Clement; Alexander, C. Scott

    2007-03-01

    This study is best characterized as new technology development for implementing new sensors to investigate the optical characteristics of a rapidly expanding debris cloud resulting from hypervelocity impact regimes of 7 to 11 km/s. Our gas guns constitute a unique test bed that match operational conditions relevant to hypervelocity impact encountered in space engagements. We have demonstrated the use of (1) terahertz sensors, (2) silicon diodes for visible regimes, (3) germanium and InGaAs sensors for the near infrared regimes, and (4) the Sandia lightning detectors which are similar to the silicon diodes described in 2. The combination and complementary use of all these techniques has the strong potential of ''thermally'' characterizing the time dependent behavior of the radiating debris cloud. Complementary spectroscopic measurements provide temperature estimates of the impact generated debris by fitting its spectrum to a blackbody radiation function. This debris is time-dependent as its transport/expansion behavior is changing with time. The rapid expansion behavior of the debris cools the cloud rapidly, changing its thermal/temperature characteristics with time. A variety of sensors that span over a wide spectrum, varying from visible regime to THz frequencies, now gives us the potential to cover the impact over a broader temporal regime starting from high pressures (Mbar) high-temperatures (eV) to low pressures (mbar) low temperatures (less than room temperature) as the debris expands and cools.

  19. The impact of lower sea-ice extent on Arctic greenhouse-gas exchange

    USGS Publications Warehouse

    Parmentier, Frans-Jan W.; Christensen, Torben R.; Sørensen, Lise Lotte; Rysgaard, Søren; McGuire, A. David; Miller, Paul A.; Walker, Donald A.

    2013-01-01

    In September 2012, Arctic sea-ice extent plummeted to a new record low: two times lower than the 1979–2000 average. Often, record lows in sea-ice cover are hailed as an example of climate change impacts in the Arctic. Less apparent, however, are the implications of reduced sea-ice cover in the Arctic Ocean for marine–atmosphere CO2 exchange. Sea-ice decline has been connected to increasing air temperatures at high latitudes. Temperature is a key controlling factor in the terrestrial exchange of CO2 and methane, and therefore the greenhouse-gas balance of the Arctic. Despite the large potential for feedbacks, many studies do not connect the diminishing sea-ice extent with changes in the interaction of the marine and terrestrial Arctic with the atmosphere. In this Review, we assess how current understanding of the Arctic Ocean and high-latitude ecosystems can be used to predict the impact of a lower sea-ice cover on Arctic greenhouse-gas exchange.

  20. Soil, Water, and Greenhouse-gas Impacts of Alternative Biomass Cropping Systems

    NASA Astrophysics Data System (ADS)

    Schulte Moore, L. A.; Bach, E.; Cambardella, C.; Hargreaves, S.; Helmers, M.; Hofmockel, K.; Isenhart, T.; Kolka, R. K.; Ontl, T.; Welsh, W.; Williams, R.; Landscape Biomass Team

    2010-12-01

    Through the 2008 Energy Independence and Security Act and other state and federal mandates, the U.S. is embarking on an aggressive agenda to reduce dependency on fossil fuels. While grain-derived ethanol will be used to largely meet initial renewable fuels targets, advanced biofuels derived from lignocellulosic materials are expected to comprise a growing proportion of the renewable energy portfolio and provide a more sustainable solution. As part of our interdisciplinary research, we are assessing the environmental impacts of four lignocellulosic biomass cropping systems and comparing them to a conventional corn cropping system. This comparison is conducted using a randomized, replicated experiment initiated in fall 2008, which compares the five cropping systems across a toposequence (i.e., floodplain, toeslope, backslope, shoulder, summit). In addition to assessing herbaceous and woody biomass yields, we are evaluating the environmental performance of these systems through changes in water quality, greenhouse-gas emissions, and carbon pools. Initial results document baseline soil parameters, including the capacity of the soils to sequester carbon across the toposequence, and the impacts of landscape heterogeneity and cropping system on soil moisture and nitrate-nitrogen levels in the vadose zone. Additional results on greenhouse-gas emissions and carbon dynamics are forthcoming from this years field research. The fuller understanding of the environmental performance of these systems will help inform federal and state policies seeking to incentivize the development of a sustainable bioenergy industry.

  1. Predictions of the Impacts of Future Marcellus Shale Natural Gas Development on Regional Ozone

    NASA Astrophysics Data System (ADS)

    Roy, A.; Adams, P. J.; Robinson, A. L.

    2012-12-01

    Recent discovery of shale gas reserves, combined with advances in drilling and fracturing technology, are leading to extensive development of natural gas in the Marcellus Shale formation which underlies parts of Pennsylvania, West Virginia, Ohio and New York. To assess the impacts of this development on regional air quality, we have constructed a VOC, NOx and PM2.5 emissions inventory for the development and production of gas from the Marcellus formation. In 2020, we estimate that Marcellus activities will contribute about 12% to both regional NOx and VOC emissions. These numbers were obtained as a best estimate (mean) from a distribution obtained through several Monte Carlo runs. We speciated these emissions for use in a 3-D chemical transport model (PMCAMx) to simulate their effects on regional ozone. The projected Marcellus emissions for 2020 were added to a 2007 base inventory developed from the NEI. We have performed multiple simulations to investigate the effects of Marcellus development on regional air quality. The model predicts significant ozone changes in the Marcellus region with a uniform increase of few ppb across a wide region of the Northeast. Sensitivity studies are being performed to investigate the effects of emissions controls and sensitivity to VOC and NOx emissions.

  2. Localising livestock protein feed production and the impact on land use and greenhouse gas emissions.

    PubMed

    Sasu-Boakye, Y; Cederberg, C; Wirsenius, S

    2014-08-01

    Livestock farmers in Sweden usually grow feed grains for livestock but import protein feed from outside Sweden. Aside from the economic implications, some environmental issues are associated with this practice. We used life cycle assessment to evaluate the impact of local protein feed production on land use and greenhouse gas emissions, compared with the use of imported protein feed, for pig meat and dairy milk produced in Sweden. Our results showed that local production reduced greenhouse gas emissions by 4.5% and 12%, respectively, for pigs and dairy cows. Land use for feed production in Sweden increased by 11% for pigs and 25% for dairy cows, but total land use decreased for pig production and increased for dairy milk production. Increased protein feed cultivation in Sweden decreased inputs needed for animal production and improved some ecological processes (e.g. nutrient recycling) of the farm systems. However, the differences in results between scenarios are relatively small and influenced to an extent by methodological choices such as co-product allocation. Moreover, it was difficult to assess the contribution of greenhouse emissions from land use change. The available accounting methods we applied did not adequately account for the potential land use changes and in some cases provided conflicting results. We conclude that local protein feed production presents an opportunity to reduce greenhouse gas emissions but at a cost of increasing land occupation in Sweden for feed production. PMID:26263191

  3. Mobile Measurements of Leaks Associated with Oil and Gas Development and the Impact on Air Quality

    NASA Astrophysics Data System (ADS)

    Herndon, Scott; DeCarlo, Peter; Yacovitch, Tara; Goetz, Douglass; Floerchinger, Cody; Roscioli, Joseph; Shorter, Joanne; Kolb, Charles

    2014-05-01

    In the United States, horizontal drilling and hydraulic fracturing technologies have enabled a rapid increase in the production rate of oil and natural gas. Frequently, the shale sources are located near large urban centers (such as Dallas/Fort Worth, TX) and smaller communities. The transient drilling activity as well as the long-term installation of wells, processing and transmission facilities have the potential to affect associated emissions to the atmosphere of methane, volatile organic compounds, NOx, particulates and other species. Using a mobile laboratory, measurements have been conducted in several active shale play production areas and at specific facilities. The regions include the Barnett shale in Dallas/Fort Worth, the Denver Julesberg Shale near Denver, and the southwest and north-central regions of the Marcellus shale near Pittsburg and Mansfield, respectively. Results of the quantification of the specific natural gas leak rate from specific facilities will be presented and discussed. Also, differences in the emissions profile from the various regions will be highlighted. The intra-regional contrasts will also be presented such as those observed in the Barnett shale in the ethane to methane ratio, demonstrating its use as an "isotope-like" signature of the source. Regional scale measurements of the observed levels of air pollutants downwind and upwind of the shale play sectors will be shown. The data from the Marcellus region will put into context on how further development of the gas resources impacts air quality in a region upwind of the highly urbanized east coast corridor.

  4. Source apportionment of atmospheric PAHs and their toxicity using PMF: Impact of gas/particle partitioning

    NASA Astrophysics Data System (ADS)

    Gao, Bo; Wang, Xin-Ming; Zhao, Xiu-Ying; Ding, Xiang; Fu, Xiao-Xin; Zhang, Yan-Li; He, Quan-Fu; Zhang, Zhou; Liu, Teng-Yu; Huang, Zou-Zhao; Chen, Lai-Guo; Peng, Yan; Guo, Hai

    2015-02-01

    24-h PM2.5 samples were simultaneously collected at six sites in a subtropical city of South China during November-December, 2009. Particle-phase concentrations of polycyclic aromatic hydrocarbons (PAHs) and organic tracers such as hopanes for vehicular emissions (VE), levoglucosan for biomass burning (BB) and picene for coal combustion (CC) were determined. Meanwhile, their gas-phase concentrations were calculated from gas/particle (G/P) partitioning theory using the particle-phase concentrations. The 4 ring PAHs (fluoranthene to chrysene) had lower particle-phase fractions (10%-79%) than other species. Estimated BaPeq and lifetime cancer risk for particle-only (P-only) vs gas + particle (G + P) data sets showed similar values, indicating PAHs with 5-7 rings dominated the carcinogenicity of PAHs. Positive Matrix Factorization (PMF) was applied on both P-only and G + P data sets to estimate the source contributions to PAHs and their toxicity. Three common sources were identified: VE, BB and CC, with CC as the most significant source for both particulate (58%) and total (G + P, 40%) PAHs. While CC exhibited consistent contributions to BaPeq for P-only (66%) vs G + P (62%) solutions, VE and BB contributions were under- and overestimated by 68% and 47%, respectively by the P-only solution, as compared to the G + P solution. The results provide an insight on the impact of G/P partitioning on the source apportionment of PAHs and their toxicity.

  5. Impact of Variations on 1-D Flow in Gas Turbine Engines via Monte Carlo Simulations

    NASA Technical Reports Server (NTRS)

    Ngo, Khiem Viet; Tumer, Irem

    2004-01-01

    The unsteady compressible inviscid flow is characterized by the conservations of mass, momentum, and energy; or simply the Euler equations. In this paper, a study of the subsonic one-dimensional Euler equations with local preconditioning is presented using a modal analysis approach. Specifically, this study investigates the behavior of airflow in a gas turbine engine using the specified conditions at the inflow and outflow boundaries of the compressor, combustion chamber, and turbine, to determine the impact of variations in pressure, velocity, temperature, and density at low Mach numbers. Two main questions motivate this research: 1) Is there any aerodynamic problem with the existing gas turbine engines that could impact aircraft performance? 2) If yes, what aspect of a gas turbine engine could be improved via design to alleviate that impact and to optimize aircraft performance? This paper presents an initial attempt to model the flow behavior in terms of their eigenfrequencies subject to the assumption of the uncertainty or variation (perturbation). The flow behavior is explored using simulation outputs from a customer-deck model obtained from Pratt & Whitney. Variations of the main variables (i.e., pressure, temperature, velocity, density) about their mean states at the inflow and outflow boundaries of the compressor, combustion chamber, and turbine are modeled. Flow behavior is analyzed for the high-pressure compressor and combustion chamber utilizing the conditions on their left and right boundaries. In the same fashion, similar analyses are carried out for the high-pressure and low-pressure turbines. In each case, the eigenfrequencies that are obtained for different boundary conditions are examined closely based on their probabilistic distributions, a result of a Monte Carlo 10,000 sample simulation. Furthermore, the characteristic waves and wave response are analyzed and contrasted among different cases, with and without preconditioners. The results reveal the existence of flow instabilities due to the combined effect of variations and excessive pressures in the case of the combustion chamber and high-pressure turbine. Finally, a discussion is presented on potential impacts of the instabilities and what can be improved via design to alleviate them for a better aircraft performance.

  6. The impact of seasonality and elevation on dissolved greenhouse gas concentrations in a northeastern Wyoming watershed

    NASA Astrophysics Data System (ADS)

    Kuhn, C.; Bettigole, C.; Raymond, P. A.; Glick, H.; Seegmiller, L.; Oliver, C.; Khadka, A.; Routh, D.

    2014-12-01

    Quantification of river and stream contributions to global carbon emission budgets using field-based measurements is key to understanding how freshwater streams act as conduits between terrestrial and atmospheric carbon pools. In order to better characterize drivers of this process, this study quantifies: a) emissions of carbon dioxide and methane from a semi-arid, high plains riverine system with montaine headwaters in order to establish baseline data for the watershed; b) the impact of stream order, seasonality and elevation on dissolved gas concentrations to better understand the spatial and temporal heterogeneity of dissolved carbon gases. To achieve the latter objective, we conducted field surveys in first and second order streams in the Clear Creek drainage of the Powder River Basin watershed. We took direct measurements of stream gases using headspace sampling at thirty sites along an elevation gradient ranging from 1,203-3,346 meters. We also intensely monitored five transects throughout the descending limb of spring runoff (June 8th-August 12th) to investigate how temperature and discharge volume impact greenhouse gas concentrations. Clear Creek, located in northeastern Wyoming, is approximately 118.4 km long with a drainage area of 2,968 km2. The creek flows east out of Bighorn National Forest where it turns northeast to converge with the Powder River about ten miles before the Montana border. The stream straddles the Middle Rockies and Northwestern Great Plains ecoregions and experiences an abrupt shift in soil type, riparian vegetation, underlying geology and stream geometry as the stream exits the mountains and enters the agricultural alluvial floodplain. These site specific biological and physical changes along the elevation gradient affect dissolved greenhouse gas concentrations.

  7. Impact origin of the Avak structure, Arctic Alaska, and genesis of the Barrow gas fields

    SciTech Connect

    Kirschner, C.E.; Grantz, A. )

    1990-05-01

    Geophysical and subsurface geologic data confirm that the Avak structure, which underlies the coastal plain 12 km southeast of Barrow, is an impact crater. The structure is a roughly circular area of chaotically deformed Upper Triassic to Lower Cretaceous sedimentary rocks 8 km in diameter bounded by a ring of anastomozing, inwardly dipping, listric normal faults. Beyond the ring, these rocks are almost flat. Basement is strongly deformed Ordovician and Silurian argillite. Strong density and seismic velocity contrast between the argillite and the overlying strata produce gravity and seismic reflection signatures that define ring anticlines around the disturbed zone and a structural high at its center. The Mesozoic strata are about 760 m thick in the adjacent Barrow gas fields, where the Neocomian pebble shale unit and the gas-producing Lower Jurassic Barrow sandstone lie at average subsea depths of 438 m and 670 m, respectively. In the Avak well, drilled on the central high, the pebble shale unit and Barrow sandstone lie near the surface, documenting more than 500 m of uplift at the high. The cores in this well also show steep dips (30-90{degree}), abundant tectonic breccia with argillite clasts 90 m above basement, fractured quartz grains, and shatter cones resembling those found in well-documented meteorite craters. Stratigraphic data suggest that the Avak meteorite struck a late Early Cretaceous marine shelf, produced peripheral highs that trapped gas in the Barrow fields, and triggered massive landslides on the adjacent outer shelf. The age of the landslides dates the impact at about 105 Ma.

  8. Using a Gas-Phase Tracer Test to Characterize the Impact of Landfill Gas Generation on Advective-Dispersive Transport of VOCs in the Vadose Zone

    PubMed Central

    Monger, Gregg R.; Duncan, Candice Morrison; Brusseau, Mark L.

    2015-01-01

    A gas-phase tracer test (GTT) was conducted at a landfill in Tucson, AZ, to help elucidate the impact of landfill gas generation on the transport and fate of chlorinated aliphatic volatile organic contaminants (VOCs). Sulfur hexafluoride (SF6) was used as the non-reactive gas tracer. Gas samples were collected from a multiport monitoring well located 15.2 m from the injection well, and analyzed for SF6, CH4, CO2, and VOCs. The travel times determined for SF6 from the tracer test are approximately two to ten times smaller than estimated travel times that incorporate transport by only gas-phase diffusion. In addition, significant concentrations of CH4 and CO2 were measured, indicating production of landfill gas. Based on these results, it is hypothesized that the enhanced rates of transport observed for SF6 are caused by advective transport associated with landfill gas generation. The rates of transport varied vertically, which is attributed to multiple factors including spatial variability of water content, refuse mass, refuse permeability, and gas generation. PMID:26380532

  9. [Analysis of the phthalates in cosmetics by capillary gas chromatography].

    PubMed

    Chen, Huiming; Wang, Chao; Wang, Xing

    2004-05-01

    A capillary gas chromatographic method with flame ionization detector (GC-FID) for the detection of the six phthalates (dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DOP)) in the cosmetics was developed. The phthalates were extracted from cosmetics with methanol under ultrasonication and then separated with high-speed centrifugation. The supernatant was dehydrated and filtrated through membrane with 0.5 microm pore diameter. The filtrate was injected into the GC system for analysis. Then the positive results observed in the GC-FID chromatogram were confirmed by gas chromatography-electron impact-mass detection (GC-EI-MS) analysis. Retention times of the peaks could be applied for qualitative analysis. External standard method was used for quantitative analysis. The recoveries of the six phthalates were between 82.90% and 109.50%. The relative standard deviations were between 2.1% and 4.6%. The detection limits of the method were: 0.1 ng for DMP, DEP, DBP and BBP, and 0.5 ng for DEHP and DOP, respectively. The method presented the advantages of high precision, high sensitivity, small sample size, and simple pretreatment. The method can be used to test the six phthalates in the cosmetics. PMID:15712902

  10. Air Quality Impacts of Greenhouse Gas Mitigation Technologies in the Power Generation and Transportation Sectors

    NASA Astrophysics Data System (ADS)

    Mac Kinnon, Michael

    Future efforts to mitigate the harmful impacts of climate change will include transitions to alternative technologies and fuels targeting reductions in greenhouse gas (GHG) emissions. Currently, economic sectors of greatest concern include transportation and power generation, which combined contribute over half of total U.S. GHG emissions. In addition to GHGs, displacement of conventional energy strategies will impact the emissions of various pollutant species with human health and environmental risks due to common generation processes and sources. In order to fully investigate the air quality (AQ) impacts of deploying various GHG mitigation technologies and fuels in coming decades, spatially and temporally resolved pollutant emissions fields are developed and utilized as input for simulations of atmospheric chemistry and transport via an advanced AQ model. Three areas of the U.S. are chosen for regional analyses in the year 2055. In order to characterize the evolution of regional energy sector emission drivers from current levels, a Base Case is developed that is representative of progression in the absence of aggressive GHG mitigation efforts. To facilitate comparison, alternative scenarios are developed to explore the effects of shifts in technologies, fuels, or behavior with the potential to mitigate GHG emissions. Scenarios are represented by generated spatially and temporally resolved emission fields and evaluated for impacts on primary and secondary air pollutant concentrations. Significant variation in energy profiles, demands, and constraints (e.g., regulatory statutes) between study domains yields significant differences in regional impacts. The magnitude of AQ improvements depends on baseline emission levels and spatial and temporal emission patterns. In addition, the current focus on reducing emissions from the targeted sectors increases the importance of emissions from other areas and sectors.

  11. Environmental health impacts of unconventional natural gas development: a review of the current strength of evidence.

    PubMed

    Werner, Angela K; Vink, Sue; Watt, Kerrianne; Jagals, Paul

    2015-02-01

    Rapid global expansion of unconventional natural gas development (UNGD) raises environmental health concerns. Many studies present information on these concerns, yet the strength of epidemiological evidence remains tenuous. This paper is a review of the strength of evidence in scientific reporting of environmental hazards from UNGD activities associated with adverse human health outcomes. Studies were drawn from peer-reviewed and grey literature following a systematic search. Five databases were searched for studies published from January 1995 through March 2014 using key search terms relevant to environmental health. Studies were screened, ranked and then reviewed according to the strength of the evidence presented on adverse environmental health outcomes associated with UNGD. The initial searches yielded >1000 studies, but this was reduced to 109 relevant studies after the ranking process. Only seven studies were considered highly relevant based on strength of evidence. Articles spanned several relevant topics, but most focussed on impacts on typical environmental media, such as water and air, with much of the health impacts inferred rather than evidenced. Additionally, the majority of studies focussed on short-term, rather than long-term, health impacts, which is expected considering the timeframe of UNGD; therefore, very few studies examined health outcomes with longer latencies such as cancer or developmental outcomes. Current scientific evidence for UNGD that demonstrates associations between adverse health outcomes directly with environmental health hazards resulting from UNGD activities generally lacks methodological rigour. Importantly, however, there is also no evidence to rule out such health impacts. While the current evidence in the scientific research reporting leaves questions unanswered about the actual environmental health impacts, public health concerns remain intense. This is a clear gap in the scientific knowledge that requires urgent attention. PMID:25461113

  12. Air Impacts of Unconventional Natural Gas Development: A Barnett Shale Case Study

    NASA Astrophysics Data System (ADS)

    Moore, C. W.; Zielinska, B.; Campbell, D.; Fujita, E.

    2013-12-01

    Many atmospheric pollutants have been linked to the lifecycle of unconventional natural gas. Attributing air emissions to particular segments of the natural gas life cycle can be difficult. Further, describing individual and community exposure to air pollutants is complex since contaminants can vary spatially and temporally, based on proximity to point sources, magnitude, transport and dispersion of emissions. Here we will present data from the Barnett Shale formation near Dallas/Fort Worth, TX with the goal of providing a better understanding of the extent to which population exposure to air toxics is associated with emissions from natural gas production operations in this region. The Barnett Shale formation covers nearly 13000 km2 and is located west of Dallas/Fort Worth, TX. This formation contains natural gas, natural gas condensate, and light oil. Samples were collected in April-May 2010 in two phases with the purpose of Phase 1 being to characterize emissions from major gas production facilities in the area, while Phase 2 involved more intensive monitoring of two residential areas identified in Phase 1. One of the residential areas was downwind of a gas well and two condensate tanks and the other area was close to a compressor station. Phase 1 sampling involved our mobile monitoring system, which includes real-time estimates of volatile organic compounds (VOC), using a portable photoionization detector monitor; continuous NO, PM2.5 mass, and a GasFindIR camera. Phase 1 also included 1-hr integrated canister VOC samples and carbonyl compound samples, using DNPH impregnated Sep-Pac Si cartridges. These samples were analyzed by GC/MS and high performance liquid chromatography with a photodiode array detector. Phase 2 sampling included 7-day integrated passive samples for NOx, NO2 and SO2 using Ogawa passive samplers, and BTEX (benzene, toluene, ethylbenzene, and xylenes), 1,3-butadiene, and carbonyl compounds (formaldehyde, acetaldehyde, and acrolein) using Radiello samplers. In addition, weekly PM2.5 samples were collected on Teflon and quartz filters that were analyzed for mass and elements (Teflon filters), for organic and elemental carbon (OC and EC) by thermal/optical reflectance (TOR) method and for polycyclic aromatic hydrocarbons (PAH) using a gas chromatography/mass spectrometry (GC/MS) technique (quartz filters).VOC emissions from condensate tanks were largely low molecular weight hydrocarbons, however these tanks were enhancing local benzene concentrations mostly through malfunctioning valves. PAH concentrations were low (in pg m-3 range) but the average PAH concentration profiles (higher fraction of methylated PAHs) indicated an influence of compressor engine exhausts and increased diesel transportation traffic. These measurements, however, only represent a small 'snap-shot' of the overall emissions picture from this area. For instance during this one month study, the compressor station was predominantly downwind of the community and this may not be the case in other times of the year. Long-term study of these systems, especially in areas that have yet to experience this type of exploration, but will in the future, is needed to truly evaluate the air impacts of unconventional natural gas development.

  13. Simulation of the impact of thunderstorm activity on atmospheric gas composition

    NASA Astrophysics Data System (ADS)

    Smyshlyaev, S. P.; Mareev, E. A.; Galin, V. Ya.

    2010-08-01

    A chemistry-climate model of the lower and middle atmosphere has been used to estimate the sensitivity of the atmospheric gas composition to the rate of thunderstorm production of nitrogen oxides at upper tropospheric and lower stratospheric altitudes. The impact that nitrogen oxides produced by lightning have on the atmospheric gas composition is treated as a subgrid-scale process and included in the model parametrically. The natural uncertainty in the global production rate of nitrogen oxides in lightning flashes was specified within limits from 2 to 20 Tg N/year. Results of the model experiments have shown that, due to the variability of thunderstorm-produced nitrogen oxides, their concentration in the upper troposphere and lower stratosphere can vary by a factor of 2 or 3, which, given the influence of nitrogen oxides on ozone and other gases, creates the potential for a strong perturbation of the atmospheric gas composition and thermal regime. Model calculations have shown the strong sensitivity of ozone and the OH hydroxyl to the amount of lightning nitrogen oxides at different atmospheric altitudes. These calculations demonstrate the importance of nitrogen oxides of thunderstorm origin for the balance of atmospheric odd ozone and gases linked to it, such as ozone and hydroxyl radicals. Our results demonstrate that one important task is to raise the accuracy of estimates of the rate of nitrogen oxide production by lightning discharges and to use physical parametrizations that take into account the local lightning effects and feedbacks arising in this case rather than climatological data in models of the gas composition and general circulation of the atmosphere.

  14. The potential near-source ozone impacts of upstream oil and gas industry emissions.

    PubMed

    Olaguer, Eduardo P

    2012-08-01

    Increased drilling in urban areas overlying shale formations and its potential impact on human health through decreased air quality make it important to estimate the contribution of oil and gas activities to photochemical smog. Flares and compressor engines used in natural gas operations, for example, are large sources not only of NOx but also offormaldehyde, a hazardous air pollutant and powerful ozone precursor We used a neighborhood scale (200 m horizontal resolution) three-dimensional (3D) air dispersion model with an appropriate chemical mechanism to simulate ozone formation in the vicinity ofa hypothetical natural gas processing facility, based on accepted estimates of both regular and nonroutine emissions. The model predicts that, under average midday conditions in June, regular emissions mostly associated with compressor engines may increase ambient ozone in the Barnett Shale by more than 3 ppb beginning at about 2 km downwind of the facility, assuming there are no other major sources of ozone precursors. Flare volumes of 100,000 cubic meters per hour ofnatural gas over a period of 2 hr can also add over 3 ppb to peak 1-hr ozone somewhatfurther (>8 km) downwind, once dilution overcomes ozone titration and inhibition by large flare emissions of NOx. The additional peak ozone from the hypothetical flare can briefly exceed 10 ppb about 16 km downwind. The enhancements of ambient ozone predicted by the model are significant, given that ozone control strategy widths are of the order of a few parts per billion. Degrading the horizontal resolution of the model to 1 km spuriously enhances the simulated ozone increases by reducing the effectiveness of ozone inhibition and titration due to artificial plume dilution. PMID:22916444

  15. Methane and its Stable Isotope Signature Across Pennsylvania: Assessing the Potential Impacts of Natural Gas Development and Agriculture

    NASA Astrophysics Data System (ADS)

    Ramos-Garcés, F.; Fuentes, J. D.; Grannas, A. M.; Martins, D. K.

    2012-12-01

    Methane is an important greenhouse gas with a global warming potential 72 times that of carbon dioxide (20 year time horizon). Many recent efforts have been focused on improving our understanding of methane sources to the atmosphere and better quantifying the atmospheric methane budget. Increased natural gas exploration, particularly associated with shale gas drilling, has been hypothesized to be a potential source of atmospheric methane during well development and also due to fugitive emissions from operational well sites and pipelines. For a six-day period in June 2012, measurements of methane and its stable isotope signature were obtained from a mobile measurement platform using cavity ringdown spectroscopy. Transects from southwestern to northeastern Pennsylvania were studied, with samples obtained in rural, forested, urban, farm-impacted and well-impacted sites. Particular emphasis was placed on performing air sampling in the vicinity of natural gas wells under development, just completed, and in full operation. In the rural atmosphere, away from cattle farms and natural gas systems, the ambient levels of methane were around 1.75 ppm. Near and around gas wells under development, ambient methane levels resembled those found in the rural atmosphere. In some cases, the atmosphere was enriched with methane (up to 2.2 ppm) in areas near old wells and existing pipelines. Ambient methane levels around cattle farms were significantly enhanced, with mixing ratios reaching about 4 ppm. We will discuss here the impact of both gas well development and agricultural activities on observed methane concentrations and stable isotope signatures.

  16. A stream-based methane monitoring approach for evaluating groundwater impacts associated with unconventional gas development.

    PubMed

    Heilweil, Victor M; Stolp, Bert J; Kimball, Briant A; Susong, David D; Marston, Thomas M; Gardner, Philip M

    2013-01-01

    Gaining streams can provide an integrated signal of relatively large groundwater capture areas. In contrast to the point-specific nature of monitoring wells, gaining streams coalesce multiple flow paths. Impacts on groundwater quality from unconventional gas development may be evaluated at the watershed scale by the sampling of dissolved methane (CH4 ) along such streams. This paper describes a method for using stream CH4 concentrations, along with measurements of groundwater inflow and gas transfer velocity interpreted by 1-D stream transport modeling, to determine groundwater methane fluxes. While dissolved ionic tracers remain in the stream for long distances, the persistence of methane is not well documented. To test this method and evaluate CH4 persistence in a stream, a combined bromide (Br) and CH4 tracer injection was conducted on Nine-Mile Creek, a gaining stream in a gas development area in central Utah. A 35% gain in streamflow was determined from dilution of the Br tracer. The injected CH4 resulted in a fivefold increase in stream CH4 immediately below the injection site. CH4 and δ(13) CCH4 sampling showed it was not immediately lost to the atmosphere, but remained in the stream for more than 2000 m. A 1-D stream transport model simulating the decline in CH4 yielded an apparent gas transfer velocity of 4.5 m/d, describing the rate of loss to the atmosphere (possibly including some microbial consumption). The transport model was then calibrated to background stream CH4 in Nine-Mile Creek (prior to CH4 injection) in order to evaluate groundwater CH4 contributions. The total estimated CH4 load discharging to the stream along the study reach was 190 g/d, although using geochemical fingerprinting to determine its source was beyond the scope of the current study. This demonstrates the utility of stream-gas sampling as a reconnaissance tool for evaluating both natural and anthropogenic CH4 leakage from gas reservoirs into groundwater and surface water. PMID:23758706

  17. Impact Resistance of Lightweight Hybrid Structures for Gas Turbine Engine Fan Containment Applications

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan G.; Noebe, Ronald D.; Revilock, Duane M.

    2003-01-01

    The ballistic impact resistance of hybrid composite sandwich structures was evaluated with the ultimate goal of developing new materials or structures for potential gas turbine engine fan containment applications. The sandwich structures investigated consisted of GLARE-5 laminates as face sheets with lightweight cellular metallic materials such as honeycomb, foam, and lattice block as a core material. The impact resistance of these hybrid sandwich structures was compared to GLARE-5 laminates and 2024-T3 Al sheet, which were tested as a function of areal weight (material thickness). The GLARE-5 laminates exhibited comparable impact properties to that of 2024-T3 Al at low areal weights, even though there were significant differences in the static tensile properties of these materials. The GLARE-5, however, did have a greater ballistic limit than straight aluminum sheet at higher areal weights. Furthermore, there is up to a 25% advantage in ballistic limit for the GLARE-5/foam sandwich structures compared to straight 2024-T3 Al. But no advantage in ballistic limit was observed between any of the hybrid sandwich structures and thicker versions of GLARE-5. Recommendations for future work are provided, based on these preliminary data.

  18. Nonlinear Oscillations of Gas Bubbles and Their Impact on Plasma Breakdown in Water

    NASA Astrophysics Data System (ADS)

    Sommers, Bradley; Foster, John

    2011-10-01

    We investigate the effects of a time varying electric field on air bubbles submerged in water. For a sufficiently strong field, a large electrical stress acting on the liquid-gas boundary can deform the volume and shape of the bubble. This deformation may drastically alter the internal pressure and polarization of the bubble, thus easing the conditions for streamer formation within the gas volume. This type of enhancement could have a broad impact on the viability of liquid plasma technologies, which tend to suffer from high voltage requirements. Bubbles with 0.5-3 mm diameter are trapped in the node of a 26.5 kHz underwater acoustic field while either alternating or pulsed voltage signals of 5-20 kV are applied across their diameter. Bubble response is captured using a high speed camera (10,000 fps), along with a high sensitivity hydrophone. The response is documented over a wide range of factors, including bubble size, field frequency, and field strength. The observed deformations of the bubble shape are then used to predict changes to the reduced field (E/N) within the bubble volume. We investigate the effects of a time varying electric field on air bubbles submerged in water. For a sufficiently strong field, a large electrical stress acting on the liquid-gas boundary can deform the volume and shape of the bubble. This deformation may drastically alter the internal pressure and polarization of the bubble, thus easing the conditions for streamer formation within the gas volume. This type of enhancement could have a broad impact on the viability of liquid plasma technologies, which tend to suffer from high voltage requirements. Bubbles with 0.5-3 mm diameter are trapped in the node of a 26.5 kHz underwater acoustic field while either alternating or pulsed voltage signals of 5-20 kV are applied across their diameter. Bubble response is captured using a high speed camera (10,000 fps), along with a high sensitivity hydrophone. The response is documented over a wide range of factors, including bubble size, field frequency, and field strength. The observed deformations of the bubble shape are then used to predict changes to the reduced field (E/N) within the bubble volume. Research supported by the NSF (CBET #1033141).

  19. The impact of soil amendments on greenhouse gas emissions: a comprehensive life cycle assessment approach

    NASA Astrophysics Data System (ADS)

    DeLonge, M. S.; Ryals, R.; Silver, W. L.

    2011-12-01

    Soil amendments, such as compost and manure, can be applied to grasslands to improve soil conditions and enhance aboveground net primary productivity. Applying such amendments can also lead to soil carbon (C) sequestration and, when materials are diverted from waste streams (e.g., landfills, manure lagoons), can offset greenhouse gas (GHG) emissions. However, amendment production and application is also associated with GHG emissions, and the net impact of these amendments remains unclear. To investigate the potential for soil amendments to reduce net GHG emissions, we developed a comprehensive, field-scale life cycle assessment (LCA) model. The LCA includes GHG (i.e., CO2, CH4, N2O) emissions of soil amendment production, application, and ecosystem response. Emissions avoided by diverting materials from landfills or manure management systems are also considered. We developed the model using field observations from grazed annual grassland in northern California (e.g., soil C; above- and belowground net primary productivity; C:N ratios; trace gas emissions from soils, manure piles, and composting), CENTURY model simulations (e.g., long-term soil C and trace gas emissions from soils under various land management strategies), and literature values (e.g., GHG emissions from transportation, inorganic fertilizer production, composting, and enteric fermentation). The LCA quantifies and contrasts the potential net GHG impacts of applying compost, manure, and commercial inorganic fertilizer to grazing lands. To estimate the LCA uncertainty, sensitivity tests were performed on the most widely ranging or highly uncertain parameters (e.g., compost materials, landfill emissions, manure management system emissions). Finally, our results are scaled-up to assess the feasibility and potential impacts of large-scale adoption of soil amendment application as a land-management strategy in California. Our base case results indicate that C sinks and emissions offsets associated with compost production and application can exceed life cycle emissions, potentially leading to a net reduction in GHG emissions of over 20 Mg CO2e per hectare of treated land. If similar results could be obtained in only 5% of California's 2,550,000 ha of rangeland, compost amendment application could offset the annual emissions of the California agriculture and forestry industries (> 28.25 million Mg CO2e, California Air Resources Board, 2008). Our findings indicate that application of compost amendments to grasslands may be an effective, beneficial, and relatively inexpensive strategy to contribute to climate change mitigation.

  20. Production of Various Carbon Nanoclusters by Impact Reaction Using Light-Gas Gun as Simulation of Asteroid Collisions in Space

    NASA Astrophysics Data System (ADS)

    Mieno, Tetsu; Hasegawa, Sunao; Mitsuishi, Kazutaka

    2011-12-01

    An impact production of carbon nanoclusters is carried out in nitrogen gas using a two-stage light-gas gun. A small polycarbonate ball (or a stainless steel ball) is injected at about 6.5 km/s into a pressurized target chamber to collide with an aluminum target (or a hexane + aluminum target) in 1 atm of nitrogen gas. We can confirm the production of many types of carbon nanoclusters such as aluminum-encapsulated carbon nanoparticles, carbon nanotubes, and balloonlike nanocarbons. Therefore, it is expected that many types of carbon nanoclusters are produced by impact reactions of asteroids in space, when such reactions take place in a carbon-rich atmosphere. Particularly on Titan satellite, a large number of carbon clusters produced by impacts of asteroids are expected to be stored.

  1. A review of water and greenhouse gas impacts of unconventional natural gas development in the United States

    SciTech Connect

    Arent, Doug; Logan, Jeff; Macknick, Jordan; Boyd, William; Medlock , Kenneth; O'Sullivan, Francis; Edmonds, James A.; Clarke, Leon E.; Huntington, Hill; Heath, Garvin; Statwick, Patricia M.; Bazilian, Morgan

    2015-01-01

    This paper reviews recent developments in the production and use of unconventional natural gas in the United States with a focus on water and greenhouse gas emission implications. If unconventional natural gas in the U.S. is produced responsibly, transported and distributed with little leakage, and incorporated into integrated energy systems that are designed for future resiliency, it could play a significant role in realizing a more sustainable energy future; however, the increased use of natural gas as a substitute for more carbon intensive fuels will alone not substantially alter world carbon dioxide concentration projections.

  2. Modeling impacts of changes in temperature and water table on C gas fluxes in an Alaskan peatland

    NASA Astrophysics Data System (ADS)

    Deng, Jia; Li, Changsheng; Frolking, Steve

    2015-07-01

    Northern peatlands have accumulated a large amount of organic carbon (C) in their thick peat profile. Climate change and associated variations in soil environments are expected to have significant impacts on the C balance of these ecosystems, but the magnitude is still highly uncertain. Verifying and understanding the influences of changes in environmental factors on C gas fluxes in biogeochemical models are essential for forecasting feedbacks between C gas fluxes and climate change. In this study, we applied a biogeochemical model, DeNitrification-DeComposition (DNDC), to assess impacts of air temperature (TA) and water table (WT) on C gas fluxes in an Alaskan peatland. DNDC was validated against field measurements of net ecosystem exchange of CO2 (NEE) and CH4 fluxes under manipulated surface soil temperature and WT conditions in a moderate rich fen. The validation demonstrates that DNDC was able to capture the observed impacts of the manipulations in soil environments on C gas fluxes. To investigate responses of C gas fluxes to changes in TA and soil water condition, we conducted a series of simulations with varying TA and WT. The results demonstrate that (1) uptake rates of CO2 at the site were reduced by either too colder or warmer temperatures and generally increased with increasing soil moisture; (2) CH4 emissions showed an increasing trend as TA increased or WT rose toward the peat surface; and (3) the site could shift from a net greenhouse gas (GHG) sink into a net GHG source under some warm and/or dry conditions. A sensitivity analysis evaluated the relative importance of TA and WT to C gas fluxes. The results indicate that both TA and WT played important roles in regulating NEE and CH4 emissions and that within the investigated ranges of the variations in TA and WT, changes in WT showed a greater impact than changes in TA on NEE, CH4 fluxes, and net C gas fluxes at the study fen.

  3. Brightness measurement of an electron impact gas ion source for proton beam writing applications

    NASA Astrophysics Data System (ADS)

    Liu, N.; Xu, X.; Pang, R.; Santhana Raman, P.; Khursheed, A.; van Kan, J. A.

    2016-02-01

    We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness that is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators.

  4. Brightness measurement of an electron impact gas ion source for proton beam writing applications.

    PubMed

    Liu, N; Xu, X; Pang, R; Santhana Raman, P; Khursheed, A; van Kan, J A

    2016-02-01

    We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness that is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators. PMID:26931964

  5. Impact origin of the Avak Structure, Arctic Alaska, and genesis of the Barrow gas fields

    USGS Publications Warehouse

    Kirschner, C.E.; Grantz, A.; Mullen, M.W.

    1992-01-01

    Geophysical and subsurface geologic data suggest that the Avak structure, which underlies the Arctic Coastal Plain 12 km southeast of Barrow, Alaska, is a hypervelocity meteorite or comet impact structure. The structure is a roughly circular area of uplifted, chaotically deformed Upper Triassic to Lower Cretaceous sedimentary rocks 8 km in diameter that is bounded by a ring of anastomosing, inwardly dipping, listric normal faults 12 km in diameter. Examination of cores from the Barrow gas fields and data concerning the age of the Avak structure suggest that the Avak meteorite struck a Late Cretaceous or Tertiary marine shelf or coastal plain between the Cenomanian (ca. 95 Ma), and deposition of the basal beds of the overlying late Pliocene and Quaternary Gubik Formation (ca. 3 Ma). -from Authors

  6. Mortality and Greenhouse Gas Impacts of Biomass and Petroleum Energy Futures in Africa

    NASA Astrophysics Data System (ADS)

    Bailis, Robert; Ezzati, Majid; Kammen, Daniel M.

    2005-04-01

    We analyzed the mortality impacts and greenhouse gas (GHG) emissions produced by household energy use in Africa. Under a business-as-usual (BAU) scenario, household indoor air pollution will cause an estimated 9.8 million premature deaths by the year 2030. Gradual and rapid transitions to charcoal would delay 1.0 million and 2.8 million deaths, respectively; similar transitions to petroleum fuels would delay 1.3 million and 3.7 million deaths. Cumulative BAU GHG emissions will be 6.7 billion tons of carbon by 2050, which is 5.6% of Africa's total emissions. Large shifts to the use of fossil fuels would reduce GHG emissions by 1 to 10%. Charcoal-intensive future scenarios using current practices increase emissions by 140 to 190%; the increase can be reduced to 5 to 36% using currently available technologies for sustainable production or potentially reduced even more with investment in technological innovation.

  7. Mortality and greenhouse gas impacts of biomass and petroleum energy futures in Africa.

    PubMed

    Bailis, Robert; Ezzati, Majid; Kammen, Daniel M

    2005-04-01

    We analyzed the mortality impacts and greenhouse gas (GHG) emissions produced by household energy use in Africa. Under a business-as-usual (BAU) scenario, household indoor air pollution will cause an estimated 9.8 million premature deaths by the year 2030. Gradual and rapid transitions to charcoal would delay 1.0 million and 2.8 million deaths, respectively; similar transitions to petroleum fuels would delay 1.3 million and 3.7 million deaths. Cumulative BAU GHG emissions will be 6.7 billion tons of carbon by 2050, which is 5.6% of Africa's total emissions. Large shifts to the use of fossil fuels would reduce GHG emissions by 1 to 10%. Charcoal-intensive future scenarios using current practices increase emissions by 140 to 190%; the increase can be reduced to 5 to 36% using currently available technologies for sustainable production or potentially reduced even more with investment in technological innovation. PMID:15802601

  8. Mortality and greenhouse gas impacts of biomass and petroleum energy futures in Africa.

    TOXLINE Toxicology Bibliographic Information

    Bailis R; Ezzati M; Kammen DM

    2005-04-01

    We analyzed the mortality impacts and greenhouse gas (GHG) emissions produced by household energy use in Africa. Under a business-as-usual (BAU) scenario, household indoor air pollution will cause an estimated 9.8 million premature deaths by the year 2030. Gradual and rapid transitions to charcoal would delay 1.0 million and 2.8 million deaths, respectively; similar transitions to petroleum fuels would delay 1.3 million and 3.7 million deaths. Cumulative BAU GHG emissions will be 6.7 billion tons of carbon by 2050, which is 5.6% of Africa's total emissions. Large shifts to the use of fossil fuels would reduce GHG emissions by 1 to 10%. Charcoal-intensive future scenarios using current practices increase emissions by 140 to 190%; the increase can be reduced to 5 to 36% using currently available technologies for sustainable production or potentially reduced even more with investment in technological innovation.

  9. Bird interactions with offshore oil and gas platforms: review of impacts and monitoring techniques.

    PubMed

    Ronconi, Robert A; Allard, Karel A; Taylor, Philip D

    2015-01-01

    Thousands of oil and gas platforms are currently operating in offshore waters globally, and this industry is expected to expand in coming decades. Although the potential environmental impacts of offshore oil and gas activities are widely recognized, there is limited understanding of their impacts on migratory and resident birds. A literature review identified 24 studies and reports of bird-platform interactions, most being qualitative and half having been peer-reviewed. The most frequently observed effect, for seabirds and landbirds, is attraction and sometimes collisions associated with lights and flares; episodic events have caused the deaths of hundreds or even thousands of birds. Though typically unpredictable, anecdotally, it is known that poor weather, such as fog, precipitation and low cloud cover, can exacerbate the effect of nocturnal attraction to lights, especially when coincidental with bird migrations. Other effects include provision of foraging and roosting opportunities, increased exposure to oil and hazardous environments, increased exposure to predators, or repulsion from feeding sites. Current approaches to monitoring birds at offshore platforms have focused on observer-based methods which can offer species-level bird identification, quantify seasonal patterns of relative abundance and distribution, and document avian mortality events and underlying factors. Observer-based monitoring is time-intensive, limited in spatial and temporal coverage, and suffers without clear protocols and when not conducted by trained, independent observers. These difficulties are exacerbated because deleterious bird-platform interaction is episodic and likely requires the coincidence of multiple factors (e.g., darkness, cloud, fog, rain conditions, occurrence of birds in vicinity). Collectively, these considerations suggest a need to implement supplemental systems for monitoring bird activities around offshore platforms. Instrument-based approaches, such as radar, cameras, acoustic recordings, and telemetry, hold promise for continuous monitoring. Recommendations are provided for a rigorous and comprehensive monitoring approach within an adaptive management framework. PMID:25261750

  10. Impact of offshore gas platforms on the structural and functional biodiversity of nematodes.

    PubMed

    Fraschetti, S; Guarnieri, G; Gambi, C; Bevilacqua, S; Terlizzi, A; Danovaro, R

    2016-04-01

    The Mediterranean Sea hosts hundreds of offshore gas platforms, whose activity represents a potential threat to marine ecosystems. Evidence from several studies indicates that nematodes can be highly sensitive to changes in the environmental quality. Here, we investigated the response of nematode assemblages to the presence of offshore gas platforms (located in the central Mediterranean Sea) in terms of spatial heterogeneity, structural and functional diversity. Since the effect of the investigated offshore platforms on macrofaunal assemblages were previously assessed by Terlizzi et al. (2008), the study provided also the opportunity to compare the response of different benthic compartments to the same impact related to fossil fuel extraction on marine environments. The platforms had a significant impact on nematode assemblages up to 1000 m distance from the structure. The effects were evident in term of: a) more homogeneous spatial distribution of nematode assemblages, b) increased trophic diversity of deposit feeders and c) changes in life strategies with an increase of opportunistic species in sediments closer to the platforms. Such effects seemed to be related to the dimension of the platform structures, rather than to chemical pollution or changes in food availability. These findings suggest that the platforms exert a physical alteration of the surrounding environment that is reflected by altered structural and functional traits of nematode biodiversity. The use of nematodes for monitoring the effects of the platforms only partially matched with the results obtained using macrofauna, providing further insights on potential outcomes on the functional response of marine assemblages to fossil fuel extraction. PMID:26878347

  11. Impact of Pilot Light Modeling on the Predicted Annual Performance of Residential Gas Water Heaters: Preprint

    SciTech Connect

    Maguire, J.; Burch, J.

    2013-08-01

    Modeling residential water heaters with dynamic simulation models can provide accurate estimates of their annual energy consumption, if the units? characteristics and use conditions are known. Most gas storage water heaters (GSWHs) include a standing pilot light. It is generally assumed that the pilot light energy will help make up standby losses and have no impact on the predicted annual energy consumption. However, that is not always the case. The gas input rate and conversion efficiency of a pilot light for a GSWH were determined from laboratory data. The data were used in simulations of a typical GSWH with and without a pilot light, for two cases: 1) the GSWH is used alone; and 2) the GSWH is the second tank in a solar water heating (SWH) system. The sensitivity of wasted pilot light energy to annual hot water use, climate, and installation location was examined. The GSWH used alone in unconditioned space in a hot climate had a slight increase in energy consumption. The GSWH with a pilot light used as a backup to an SWH used up to 80% more auxiliary energy than one without in hot, sunny locations, from increased tank losses.

  12. Impact of Salinity on the Air-Water Partition Coefficient of Gas Tracers

    SciTech Connect

    Zhong, Lirong; Pope, Gary A.; Evans, John C.; Cameron, Richard J.

    2005-09-01

    The use of a gas partitioning interwell tracer test (PITT) has been proposed as a standard approach to the measurement of field-scale vadose zone water saturation fractions. The accuracy of the saturation measurement is largely dependent on the determination of the air-water partitioning coefficient, K, of the tracers; however, in practice, K is also strongly influenced by the physical and chemical properties of the water. In this study, column tests were conducted to investigate the impact of salinity on tracer partitioning coefficients for two promising gas phase candidate tracers, dibromomethane and dimethylether. Sodium thiosulfate was used as a salinity surrogate. The dynamic K values of the two partitioning tracers were measured for sodium thiosulfate concentrations between 0% and 36% by weight. Methane was used as the non-partitioning tracer for all experiments. K values were found to decrease significantly with increasing sodium thiosulfate concentration. Similar correlations between K values and sodium thiosulfate concentration were found for both of the partitioning tracers tested.

  13. The impact of municipal solid waste management on greenhouse gas emissions in the United States.

    PubMed

    Weitz, Keith A; Thorneloe, Susan A; Nishtala, Subba R; Yarkosky, Sherry; Zannes, Maria

    2002-09-01

    Technological advancements, environmental regulations, and emphasis on resource conservation and recovery have greatly reduced the environmental impacts of municipal solid waste (MSW) management, including emissions of greenhouse gases (GHGs). This study was conducted using a life-cycle methodology to track changes in GHG emissions during the past 25 years from the management of MSW in the United States. For the baseline year of 1974, MSW management consisted of limited recycling, combustion without energy recovery, and landfilling without gas collection or control. This was compared with data for 1980, 1990, and 1997, accounting for changes in MSW quantity, composition, management practices, and technology. Over time, the United States has moved toward increased recycling, composting, combustion (with energy recovery) and landfilling with gas recovery, control, and utilization. These changes were accounted for with historical data on MSW composition, quantities, management practices, and technological changes. Included in the analysis were the benefits of materials recycling and energy recovery to the extent that these displace virgin raw materials and fossil fuel electricity production, respectively. Carbon sinks associated with MSW management also were addressed. The results indicate that the MSW management actions taken by U.S. communities have significantly reduced potential GHG emissions despite an almost 2-fold increase in waste generation. GHG emissions from MSW management were estimated to be 36 million metric tons carbon equivalents (MMTCE) in 1974 and 8 MMTCE in 1997. If MSW were being managed today as it was in 1974, GHG emissions would be approximately 60 MMTCE. PMID:12269661

  14. ASSESSMENT OF THE IMPACT OF TOA PARTITIONING ON DWPF MELTER OFF-GAS FLAMMABILITY

    SciTech Connect

    Daniel, G.

    2013-06-18

    An assessment has been made to evaluate the impact on the DWPF melter off-gas flammability of increasing the amount of TOA in the current solvent used in the Modular Caustic-Side Solvent Extraction Process Unit (MCU) process. The results of this study showed that the concentrations of nonvolatile carbon of the current solvent limit (150 ppm) in the Slurry Mix Evaporator (SME) product would be about 7% higher and the nonvolatile hydrogen would be 2% higher than the actual current solvent (126 ppm) with an addition of up to 3 ppm of TOA when the concentration of Isopar L in the effluent transfer is controlled below 87 ppm and the volume of MCU effluent transfer to DWPF is limited to 15,000 gallons per Sludge Receipt and Adjustment Tank (SRAT)/SME cycle. Therefore, the DWPF melter off-gas flammability assessment is conservative for up to an additional 3 ppm of TOA in the effluent based on these assumptions. This report documents the calculations performed to reach this conclusion.

  15. Aluminum/ammonia heat pipe gas generation and long term system impact for the Space Telescope's Wide Field Planetary Camera

    NASA Technical Reports Server (NTRS)

    Jones, J. A.

    1983-01-01

    In the Space Telescope's Wide Field Planetary Camera (WFPC) project, eight heat pipes (HPs) are used to remove heat from the camera's inner electronic sensors to the spacecraft's outer, cold radiator surface. For proper device functioning and maximization of the signal-to-noise ratios, the Charge Coupled Devices (CCD's) must be maintained at -95 C or lower. Thermoelectric coolers (TEC's) cool the CCD's, and heat pipes deliver each TEC's nominal six to eight watts of heat to the space radiator, which reaches an equilibrium temperature between -15 C to -70 C. An initial problem was related to the difficulty to produce gas-free aluminum/ammonia heat pipes. An investigation was, therefore, conducted to determine the cause of the gas generation and the impact of this gas on CCD cooling. In order to study the effect of gas slugs in the WFPC system, a separate HP was made. Attention is given to fabrication, testing, and heat pipe gas generation chemistry studies.

  16. Stealing the Gas: Giant Impacts and the Large Diversity in Exoplanet Densities

    NASA Astrophysics Data System (ADS)

    Inamdar, Niraj K.; Schlichting, Hilke E.

    2016-02-01

    Although current sensitivity limits are such that true solar system analogs remain challenging to detect, numerous planetary systems have been discovered that are very different from our own solar system. The majority of systems harbor a new class of planets, bodies that are typically several times more massive than the Earth but orbit their host stars well inside the orbit of Mercury. These planets frequently show evidence for large hydrogen and helium envelopes containing several percent of the planet’s mass and display a large diversity in mean densities. Here we show that this wide range can be achieved by one or two late giant impacts, which are frequently needed to achieve long-term orbital stability in multiple planet systems once the gas disk has disappeared. We demonstrate using hydrodynamical simulations that a single collision between similarly sized exoplanets can easily reduce the envelope-to-core-mass ratio by a factor of two and show that this leads to a corresponding increase in the observed mean density by factors of two to three. In addition, we investigate how envelope mass loss depends on envelope mass, planet radius, semimajor axis, and the mass distribution inside the envelope. We propose that a small number of giant impacts may be responsible for the large observed spread in mean densities, especially for multiple-planet systems that contain planets with very different densities and have not been significantly sculpted by photoevaporation.

  17. Impacts of Vehicle Weight Reduction via Material Substitution on Life-Cycle Greenhouse Gas Emissions

    SciTech Connect

    Kelly, Jarod C.; Sullivan, John L.; Burnham, Andrew; Elgowainy, Amgad

    2015-10-20

    This study examines the vehicle-cycle impacts associated with substituting lightweight materials for those currently found in light-duty passenger vehicles. We determine part-based energy use and greenhouse gas (GHG) emission ratios by collecting material substitution data from both the literature and automotive experts and evaluating that alongside known mass-based energy use and GHG emission ratios associated with material pair substitutions. Several vehicle parts, along with full vehicle systems, are examined for lightweighting via material substitution to observe the associated impact on GHG emissions. Results are contextualized by additionally examining fuel-cycle GHG reductions associated with mass reductions relative to the baseline vehicle during the use phase and also determining material pair breakeven driving distances for GHG emissions. The findings show that, while material substitution is useful in reducing vehicle weight, it often increases vehicle-cycle GHGs depending upon the material substitution pair. However, for a vehicle’s total life cycle, fuel economy benefits are greater than the increased burdens associated with the vehicle manufacturing cycle, resulting in a net total life-cycle GHG benefit. The vehicle cycle will become increasingly important in total vehicle life-cycle GHGs, since fuel-cycle GHGs will be gradually reduced as automakers ramp up vehicle efficiency to meet fuel economy standards.

  18. Sulfur Isotopes in Gas-rich Impact-Melt Glasses in Shergottites

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; Hoppe, P.; Sutton, S. R.; Nyquist, Laurence E.; Huth, J.

    2010-01-01

    Large impact melt glasses in some shergottites contain huge amounts of Martian atmospheric gases and they are known as gas-rich impact-melt (GRIM) glasses. By studying the neutron-induced isotopic deficits and excesses in Sm-149 and Sm-150 isotopes resulting from Sm-149 (n,gamma) 150Sm reaction and 80Kr excesses produced by Br-79 (n,gamma) Kr-80 reaction in the GRIM glasses using mass-spectrometric techniques, it was shown that these glasses in shergottites EET79001 and Shergotty contain regolith materials irradiated by a thermal neutron fluence of approx.10(exp 15) n/sq cm near Martian surface. Also, it was shown that these glasses contain varying amounts of sulfates and sulfides based on the release patterns of SO2 (sulfate) and H2S (sulfide) using stepwise-heating mass-spectrometric techniques. Furthermore, EMPA and FE-SEM studies in basaltic-shergottite GRIM glasses EET79001, LithB (,507& ,69), Shergotty (DBS I &II), Zagami (,992 & ,994) showed positive correlation between FeO and "SO3" (sulfide + sulfate), whereas those belonging to olivine-phyric shergottites EET79001, LithA (,506, & ,77) showed positive correlation between CaO/Al2O3 and "SO3".

  19. Decreasing Impact Tilt on a High Performance Two-Stage Gas Gun

    NASA Astrophysics Data System (ADS)

    Byers, M. E.; Rigg, P. A.; Esparza, J. S.

    2007-06-01

    There are four high-performance two-stage light gas guns in operation in the DOE complex. All four guns are similar in performance and diagnostics capabilities. Projectile velocity on these guns has typically been measured using a combination of magnetic coils and two frames of flash radiography. This requires that the projectile be in 'free flight' for a long distance (18 to 25 inches typical) in order to capture the projectile in flight. This leads to typical projectile tilt at impact in excess of 10 mrad. Recently, we have replaced the coil/x-ray system on the LANL high performance two-stage gun with Photonic Doppler Velocimetry (PDV) to obtain high accuracy (0.1%) projectile velocity measurements. This allows us to move the target very close to the end of the barrel to potentially decrease the impact tilt significantly. We will present the results of this study and compare them to the performance of the gun when the free flight section was present.

  20. Enhanced formation of disinfection byproducts in shale gas wastewater-impacted drinking water supplies.

    PubMed

    Parker, Kimberly M; Zeng, Teng; Harkness, Jennifer; Vengosh, Avner; Mitch, William A

    2014-10-01

    The disposal and leaks of hydraulic fracturing wastewater (HFW) to the environment pose human health risks. Since HFW is typically characterized by elevated salinity, concerns have been raised whether the high bromide and iodide in HFW may promote the formation of disinfection byproducts (DBPs) and alter their speciation to more toxic brominated and iodinated analogues. This study evaluated the minimum volume percentage of two Marcellus Shale and one Fayetteville Shale HFWs diluted by fresh water collected from the Ohio and Allegheny Rivers that would generate and/or alter the formation and speciation of DBPs following chlorination, chloramination, and ozonation treatments of the blended solutions. During chlorination, dilutions as low as 0.01% HFW altered the speciation toward formation of brominated and iodinated trihalomethanes (THMs) and brominated haloacetonitriles (HANs), and dilutions as low as 0.03% increased the overall formation of both compound classes. The increase in bromide concentration associated with 0.01-0.03% contribution of Marcellus HFW (a range of 70-200 μg/L for HFW with bromide = 600 mg/L) mimics the increased bromide levels observed in western Pennsylvanian surface waters following the Marcellus Shale gas production boom. Chloramination reduced HAN and regulated THM formation; however, iodinated trihalomethane formation was observed at lower pH. For municipal wastewater-impacted river water, the presence of 0.1% HFW increased the formation of N-nitrosodimethylamine (NDMA) during chloramination, particularly for the high iodide (54 ppm) Fayetteville Shale HFW. Finally, ozonation of 0.01-0.03% HFW-impacted river water resulted in significant increases in bromate formation. The results suggest that total elimination of HFW discharge and/or installation of halide-specific removal techniques in centralized brine treatment facilities may be a better strategy to mitigate impacts on downstream drinking water treatment plants than altering disinfection strategies. The potential formation of multiple DBPs in drinking water utilities in areas of shale gas development requires comprehensive monitoring plans beyond the common regulated DBPs. PMID:25203743

  1. Including impacts of particulate emissions on marine ecosystems in life cycle assessment: the case of offshore oil and gas production.

    PubMed

    Veltman, Karin; Huijbregts, Mark A J; Rye, Henrik; Hertwich, Edgar G

    2011-10-01

    Life cycle assessment is increasingly used to assess the environmental performance of fossil energy systems. Two of the dominant emissions of offshore oil and gas production to the marine environment are the discharge of produced water and drilling waste. Although environmental impacts of produced water are predominantly due to chemical stressors, a major concern regarding drilling waste discharge is the potential physical impact due to particles. At present, impact indicators for particulate emissions are not yet available in life cycle assessment. Here, we develop characterization factors for 2 distinct impacts of particulate emissions: an increased turbidity zone in the water column and physical burial of benthic communities. The characterization factor for turbidity is developed analogous to characterization factors for toxic impacts, and ranges from 1.4 PAF (potentially affected fraction) m(3) /d/kg(p) (kilogram particulate) to 7.0 x 10 [corrected] for drilling mud particles discharged from the rig. The characterization factor for burial describes the volume of sediment that is impacted by particle deposition on the seafloor and equals 2.0 10(-1) PAF m(3) /d/kg(p) for cutting particles. This characterization factor is quantified on the basis of initial deposition layer characteristics, such as height and surface area, the initial benthic response, and the recovery rate. We assessed the relevance of including particulate emissions in an impact assessment of offshore oil and gas production. Accordingly, the total impact on the water column and on the sediment was quantified based on emission data of produced water and drilling waste for all oil and gas fields on the Norwegian continental shelf in 2008. Our results show that cutting particles contribute substantially to the total impact of offshore oil and gas production on marine sediments, with a relative contribution of 55% and 31% on the regional and global scale, respectively. In contrast, the contribution of particulate emissions to the total impact on the marine water column is of minor importance. We conclude that particles are an important stressor in marine ecosystems, particularly for marine sediment, and particulate emissions should therefore be included in a (life cycle) impact assessment of offshore oil and gas production. PMID:21735543

  2. Potential of Best Practice to Reduce Impacts from Oil and Gas Projects in the Amazon

    PubMed Central

    Finer, Matt; Jenkins, Clinton N.; Powers, Bill

    2013-01-01

    The western Amazon continues to be an active and controversial zone of hydrocarbon exploration and production. We argue for the urgent need to implement best practices to reduce the negative environmental and social impacts associated with the sector. Here, we present a three-part study aimed at resolving the major obstacles impeding the advancement of best practice in the region. Our focus is on Loreto, Peru, one of the largest and most dynamic hydrocarbon zones in the Amazon. First, we develop a set of specific best practice guidelines to address the lack of clarity surrounding the issue. These guidelines incorporate both engineering-based criteria and key ecological and social factors. Second, we provide a detailed analysis of existing and planned hydrocarbon activities and infrastructure, overcoming the lack of information that typically hampers large-scale impact analysis. Third, we evaluate the planned activities and infrastructure with respect to the best practice guidelines. We show that Loreto is an extremely active hydrocarbon front, highlighted by a number of recent oil and gas discoveries and a sustained government push for increased exploration. Our analyses reveal that the use of technical best practice could minimize future impacts by greatly reducing the amount of required infrastructure such as drilling platforms and access roads. We also document a critical need to consider more fully the ecological and social factors, as the vast majority of planned infrastructure overlaps sensitive areas such as protected areas, indigenous territories, and key ecosystems and watersheds. Lastly, our cost analysis indicates that following best practice does not impose substantially greater costs than conventional practice, and may in fact reduce overall costs. Barriers to the widespread implementation of best practice in the Amazon clearly exist, but our findings show that there can be great benefits to its implementation. PMID:23650541

  3. Trace gas/aerosol boundary concentrations and their impacts on continental-scale AQMEII modeling domains

    NASA Astrophysics Data System (ADS)

    Schere, Kenneth; Flemming, Johannes; Vautard, Robert; Chemel, Charles; Colette, Augustin; Hogrefe, Christian; Bessagnet, Bertrand; Meleux, Frederik; Mathur, Rohit; Roselle, Shawn; Hu, Rong-Ming; Sokhi, Ranjeet S.; Rao, S. Trivikrama; Galmarini, Stefano

    2012-06-01

    Over twenty modeling groups are participating in the Air Quality Model Evaluation International Initiative (AQMEII) in which a variety of mesoscale photochemical and aerosol air quality modeling systems are being applied to continental-scale domains in North America and Europe for 2006 full-year simulations for model inter-comparisons and evaluations. To better understand the reasons for differences in model results among these participating groups, each group was asked to use the same source of emissions and boundary concentration data for their simulations. This paper describes the development and application of the boundary concentration data for this AQMEII modeling exercise. The European project known as GEMS (Global and regional Earth-system Monitoring using Satellite and in-situ data) has produced global-scale re-analyses of air quality for several years, including 2006 (http://gems.ecmwf.int). The GEMS trace gas and aerosol data were made available at 3-hourly intervals on a regular latitude/longitude grid of approximately 1.9 resolution within 2 cut-outs from the global model domain. One cut-out was centered over North America and the other over Europe, covering sufficient spatial domain for each modeling group to extract the necessary time- and space-varying (horizontal and vertical) concentrations for their mesoscale model boundaries. Examples of the impact of these boundary concentrations on the AQMEII continental simulations are presented to quantify the sensitivity of the simulations to boundary concentrations. In addition, some participating groups were not able to use the GEMS data and instead relied upon other sources for their boundary concentration specifications. These are noted, and the contrasting impacts of other data sources for boundary data are presented. How one specifies four-dimensional boundary concentrations for mesoscale air quality simulations can have a profound impact on the model results, and hence, this aspect of data preparation must be performed with considerable care.

  4. Transient Climate Impacts for Scenarios of Aerosol Emissions from Asia: A Story of Coal versus Gas

    NASA Astrophysics Data System (ADS)

    Grandey, B. S.; Cheng, H.; Wang, C.

    2014-12-01

    Projections of anthropogenic aerosol emissions are uncertain. In Asia, it is possible that emissions may increase if business continues as usual, with economic growth driving an increase in coal burning. But it is also possible that emissions may decrease rapidly due to the widespread adoption of cleaner technology or a shift towards non-coal fuels, such as natural gas. In this study, the transient climate impacts of three aerosol emissions scenarios are investigated: an RCP4.5 (Representative Concentration Pathway 4.5) control; a scenario with reduced Asian anthropogenic aerosol emissions; and a scenario with enhanced Asian anthropogenic aerosol emissions. A coupled atmosphere-ocean configuration of CESM (Community Earth System Model), including CAM5 (Community Atmosphere Model version 5), is used. Enhanced Asian aerosol emissions are found to delay global mean warming by one decade at the end of the century. Aerosol-induced suppression of the East Asian and South Asian summer monsoon precipitation occurs. The enhanced Asian aerosol emissions also remotely impact precipitation in other parts of the world: over the Sahel, West African monsoon precipitation is suppressed; and over Australia, austral summer monsoon precipitation is enhanced. These remote impacts on precipitation are associated with a southward shift of the ITCZ. The aerosol-induced sea surface temperature (SST) response appears to play an important role in the precipitation changes over South Asia and Australia, but not over East Asia. These results indicate that energy production in Asia, through the consequent aerosol emissions and associated radiative effects, might significantly influence future climate both locally and globally.

  5. The impact of meteorological forcings on gas phase air pollutants over Europe

    NASA Astrophysics Data System (ADS)

    Watson, Laura; Lacressonnière, Gwendoline; Gauss, Michael; Engardt, Magnuz; Andersson, Camilla; Josse, Béatrice; Marécal, Virginie; Nyiri, Agnes; Sobolowski, Stefan; Siour, Guillaume; Vautard, Robert

    2015-10-01

    The impact of meteorological forcings on gas phase air pollutants (ozone and nitrogen dioxide) over Europe was studied using four offline chemistry transport models (CTMs) as part of the IMPACT2C project. This study uses long (20- and 30-year) simulations to evaluate the present-day performance of the CTMs, which is a necessary first step before undertaking any analysis of future air quality impacts. Two sets of meteorological forcings were used for each model: reanalysis of past observation data (ERA-Interim) and Global Climate Model (GCM) output. The results for the simulations forced by reanalysis data were assessed in relation to AirBase v7 measurement data, and it was determined that all four models slightly overpredict annual O3 values (mean biases range between 0.7 and 6.6 ppb) and three out of the four models underpredict observed annual NO2 (mean biases range between -3.1 and -5.2 ppb). The simulations forced by climate models result in spatially averaged monthly concentrations of O3 that are generally between 0 and 5 ppb higher than the values obtained from simulations forced by reanalysis data; therefore it was concluded that the use of climate models introduces an additional bias to the results, but this bias tends not to be significant in the majority of cases. The bias in O3 results appears to be correlated mainly to differences in temperature and boundary layer height between the two types of simulations, whereas the less significant bias in NO2 is negatively correlated to temperature and boundary layer height. It is also clear that the selection of chemical boundary conditions is an important factor in determining the variability of O3 model results. These results will be used as a baseline for the interpretation of future work, which will include an analysis of future climate scenarios upon European air quality.

  6. Potential of best practice to reduce impacts from oil and gas projects in the Amazon.

    PubMed

    Finer, Matt; Jenkins, Clinton N; Powers, Bill

    2013-01-01

    The western Amazon continues to be an active and controversial zone of hydrocarbon exploration and production. We argue for the urgent need to implement best practices to reduce the negative environmental and social impacts associated with the sector. Here, we present a three-part study aimed at resolving the major obstacles impeding the advancement of best practice in the region. Our focus is on Loreto, Peru, one of the largest and most dynamic hydrocarbon zones in the Amazon. First, we develop a set of specific best practice guidelines to address the lack of clarity surrounding the issue. These guidelines incorporate both engineering-based criteria and key ecological and social factors. Second, we provide a detailed analysis of existing and planned hydrocarbon activities and infrastructure, overcoming the lack of information that typically hampers large-scale impact analysis. Third, we evaluate the planned activities and infrastructure with respect to the best practice guidelines. We show that Loreto is an extremely active hydrocarbon front, highlighted by a number of recent oil and gas discoveries and a sustained government push for increased exploration. Our analyses reveal that the use of technical best practice could minimize future impacts by greatly reducing the amount of required infrastructure such as drilling platforms and access roads. We also document a critical need to consider more fully the ecological and social factors, as the vast majority of planned infrastructure overlaps sensitive areas such as protected areas, indigenous territories, and key ecosystems and watersheds. Lastly, our cost analysis indicates that following best practice does not impose substantially greater costs than conventional practice, and may in fact reduce overall costs. Barriers to the widespread implementation of best practice in the Amazon clearly exist, but our findings show that there can be great benefits to its implementation. PMID:23650541

  7. Impact of emissions from natural gas production facilities on ambient air quality in the Barnett Shale area: a pilot study.

    PubMed

    Zielinska, Barbara; Campbell, Dave; Samburova, Vera

    2014-12-01

    Rapid and extensive development of shale gas resources in the Barnett Shale region of Texas in recent years has created concerns about potential environmental impacts on water and air quality. The purpose of this study was to provide a better understanding of the potential contributions of emissions from gas production operations to population exposure to air toxics in the Barnett Shale region. This goal was approached using a combination of chemical characterization of the volatile organic compound (VOC) emissions from active wells, saturation monitoring for gaseous and particulate pollutants in a residential community located near active gas/oil extraction and processing facilities, source apportionment of VOCs measured in the community using the Chemical Mass Balance (CMB) receptor model, and direct measurements of the pollutant gradient downwind of a gas well with high VOC emissions. Overall, the study results indicate that air quality impacts due to individual gas wells and compressor stations are not likely to be discernible beyond a distance of approximately 100 m in the downwind direction. However, source apportionment results indicate a significant contribution to regional VOCs from gas production sources, particularly for lower-molecular-weight alkanes (< C6). Although measured ambient VOC concentrations were well below health-based safe exposure levels, the existence of urban-level mean concentrations of benzene and other mobile source air toxics combined with soot to total carbon ratios that were high for an area with little residential or commercial development may be indicative of the impact of increased heavy-duty vehicle traffic related to gas production. Implications: Rapid and extensive development of shale gas resources in recent years has created concerns about potential environmental impacts on water and air quality. This study focused on directly measuring the ambient air pollutant levels occurring at residential properties located near natural gas extraction and processing facilities, and estimating the relative contributions from gas production and motor vehicle emissions to ambient VOC concentrations. Although only a small-scale case study, the results may be useful for guidance in planning future ambient air quality studies and human exposure estimates in areas of intensive shale gas production. PMID:25562933

  8. Regional ozone impacts of increased natural gas use in the Texas power sector and development in the Eagle Ford shale.

    PubMed

    Pacsi, Adam P; Kimura, Yosuke; McGaughey, Gary; McDonald-Buller, Elena C; Allen, David T

    2015-03-17

    The combined emissions and air quality impacts of electricity generation in the Texas grid and natural gas production in the Eagle Ford shale were estimated at various natural gas price points for the power sector. The increased use of natural gas in the power sector, in place of coal-fired power generation, drove reductions in average daily maximum 8 h ozone concentration of 0.6-1.3 ppb in northeastern Texas for a high ozone episode used in air quality planning. The associated increase in Eagle Ford upstream oil and gas production nitrogen oxide (NOx) emissions caused an estimated local increase, in south Texas, of 0.3-0.7 ppb in the same ozone metric. In addition, the potential ozone impacts of Eagle Ford emissions on nearby urban areas were estimated. On the basis of evidence from this work and a previous study on the Barnett shale, the combined ozone impact of increased natural gas development and use in the power sector is likely to vary regionally and must be analyzed on a case by case basis. PMID:25723953

  9. A framework to predict the impacts of shale gas infrastructures on the forest fragmentation of an agroforest region.

    PubMed

    Racicot, Alexandre; Babin-Roussel, Véronique; Dauphinais, Jean-François; Joly, Jean-Sébastien; Noël, Pascal; Lavoie, Claude

    2014-05-01

    We propose a framework to facilitate the evaluation of the impacts of shale gas infrastructures (well pads, roads, and pipelines) on land cover features, especially with regards to forest fragmentation. We used a geographic information system and realistic development scenarios largely inspired by the PA (United States) experience, but adapted to a region of QC (Canada) with an already fragmented forest cover and a high gas potential. The scenario with the greatest impact results from development limited by regulatory constraints only, with no access to private roads for connecting well pads to the public road network. The scenario with the lowest impact additionally integrates ecological constraints (deer yards, maple woodlots, and wetlands). Overall the differences between these two scenarios are relatively minor, with <1 % of the forest cover lost in each case. However, large areas of core forests would be lost in both scenarios and the number of forest patches would increase by 13-21 % due to fragmentation. The pipeline network would have a much greater footprint on the land cover than access roads. Using data acquired since the beginning of the shale gas industry, we show that it is possible, within a reasonable time frame, to produce a robust assessment of the impacts of shale gas extraction. The framework we propose could easily be applied to other contexts or jurisdictions. PMID:24554146

  10. 78 FR 21347 - Supplemental Draft Environmental Impact Statement for Effects of Oil and Gas Activities in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... Statement for Effects of Oil and Gas Activities in the Arctic Ocean AGENCY: National Marine Fisheries... released for public comment the ``Supplemental Draft Environmental Impact Statement (DEIS) for the Effects... content of the Supplemental DEIS can be found in the Notice of Availability (78 FR 19212, March 29,...

  11. A Framework to Predict the Impacts of Shale Gas Infrastructures on the Forest Fragmentation of an Agroforest Region

    NASA Astrophysics Data System (ADS)

    Racicot, Alexandre; Babin-Roussel, Vronique; Dauphinais, Jean-Franois; Joly, Jean-Sbastien; Nol, Pascal; Lavoie, Claude

    2014-05-01

    We propose a framework to facilitate the evaluation of the impacts of shale gas infrastructures (well pads, roads, and pipelines) on land cover features, especially with regards to forest fragmentation. We used a geographic information system and realistic development scenarios largely inspired by the PA (United States) experience, but adapted to a region of QC (Canada) with an already fragmented forest cover and a high gas potential. The scenario with the greatest impact results from development limited by regulatory constraints only, with no access to private roads for connecting well pads to the public road network. The scenario with the lowest impact additionally integrates ecological constraints (deer yards, maple woodlots, and wetlands). Overall the differences between these two scenarios are relatively minor, with <1 % of the forest cover lost in each case. However, large areas of core forests would be lost in both scenarios and the number of forest patches would increase by 13-21 % due to fragmentation. The pipeline network would have a much greater footprint on the land cover than access roads. Using data acquired since the beginning of the shale gas industry, we show that it is possible, within a reasonable time frame, to produce a robust assessment of the impacts of shale gas extraction. The framework we propose could easily be applied to other contexts or jurisdictions.

  12. 78 FR 42516 - Iroquois Gas Transmission System, L.P.; Notice of Intent To Prepare an Environmental Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-16

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Iroquois Gas Transmission System, L.P.; Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Wright Interconnect Project and Request for Comments on Environmental Issues The staff of the...

  13. NONWATER QUALITY IMPACTS OF CLOSED-CYCLE COOLING SYSTEMS AND THE INTERACTION OF STACK GAS AND COOLING TOWER PLUMES

    EPA Science Inventory

    The report gives results of a literature survey of the nonwater quality impacts of closed-cycle cooling systems. Following discussions of cooling tower and stack gas plumes, interactions of these plumes are considered. For cooling tower plumes, plume types, behavior, salt drift g...

  14. Impact of wood pruning to greenhouse gas emissions in three orchards and a vineyard

    NASA Astrophysics Data System (ADS)

    Germer, Sonja; Schleicher, Sarah; Bischoff, Wolf-Anno; Gomez Palermo, Maider; Kern, Jürgen

    2015-04-01

    Pruning of orchards and vineyards is usually burned or left on the soil for nutrient and organic carbon recycling. Recently the interest rose to extract pruning for energetic use. Very few studies exist that analyzed the effects of pruning removal on soil physical and chemical characteristics. This is linked to the fact that changes are expected rather in the long term, but project funding is typically restricted to 2 or 3 years. Some soil characteristics, however, as organic carbon content and greenhouse gas emissions might also change on the short term as our literature review reveals. The main objective of this research is to determine if pruning extraction from orchards and vineyards impact greenhouse gas emissions (N2O, CH4, and CO2) from soil to the atmosphere, change soil nitrogen and carbon content or effect nitrogen leaching. Results from our study and from the literature will be compiled to formulate best management practices for sustainable pruning utilization from orchards and vineyards. Here we compare four different study sites in a block design over two rows each with two parcels where we extracted pruning and two parcels where pruning was chipped and left on the soil (n=4). Comparisons were made for initial soil chemistry and greenhouse gas emissions in a cherry orchard without irrigation in Germany, a vineyard without irrigation in France, an almond orchard with drip irrigation in Spain and a peach orchard with flood irrigation in Spain. Soil greenhouse gas emissions depend on soil chemistry and soil moisture. These characteristics can be expected to vary between the tree rows and inter-rows of orchards. Therefore we took soil samples from row and inter-row positions of each study site and analyzed them for chemical parameters (pH, total C, N, S, and H, and available PO4, NH4, NO3, K, Mg, Ca). Additionally soil moisture and temperature data have been recorded for tree rows and inter-rows in the cherry orchard and the vineyard. Gas samples were taken with closed chambers twice a month in both row positions from all four study sites. Results reveal some initial differences of soil chemical parameter, in particular for the cherry orchard. No pruning treatment effects were found during the first growing season after treatment installation. We found, however, differences in CO2 emissions according to the sampling position in the orchards during the summer months. CO2 emissions were higher in the inter-row in vineyards than in the vine rows. In the cherry and almond orchard the opposite was found with higher CO2 emissions in tree rows than inter-rows. This finding indicates that possible pruning effects on greenhouse gas emissions that might get apparent in the long term can vary according to sampling position.

  15. Greenhouse Gas and Particulate Emissions and Impacts from Cooking Technologies in Africa

    NASA Astrophysics Data System (ADS)

    Kammen, D. M.; Bailis, R.; Kituyi, E.; Ezzati, M.

    2003-12-01

    In much of Africa, the largest fraction of energy consumption occurs within the residential sector and is derived primarily from woodfuels burned in simple stoves with poor combustion characteristics. Many of the products of incomplete combustion (PICs) are damaging to human health, particularly when they are concentrated in poorly ventilated indoor environments. Incomplete combustion also has potentially harmful impacts on the climate. Prevalent PICs include methane, a potent greenhouse gas (GHG) that is among the pollutants subject to controls under the Kyoto Protocol as well as carbon monoxide (CO), non-methane hydrocarbons (NMHCs) and particulate matter (PM), which can all have an effect on climate, but are not subject to controls under Kyoto. In addition, when woodfuels are used at a rate that reduces standing stocks of trees over the medium or long term, the CO2 released by combustion also has an impact. The choice of stove and fuel technology can have a significant impact on the emission of GHGs as well as on human exposure to health damaging pollutants. In this paper we analyze the emissions of different household energy technologies on a life-cycle basis. We use emission factors to estimate the emissions associated with production, distribution and end-use of common household fuels and assess the likely impacts of these emissions on public health and the global environment. We focus largely on charcoal, a popular fuel in many sub-Saharan African countries. Charcoal is produced by heating wood in the absence of sufficient air for complete combustion to occur. This process removes moisture and most of the volatile compounds. The compounds driven off in the process consist of condensable tars as well as many gaseous hydrocarbons, including ~40 g CH4 per kg of charcoal produced. Combining upstream and end-use emissions, every meal cooked with charcoal has 2-10 times the global warming effect of cooking the same meal with firewood and 5-12 times the effect of cooking the same meal with LPG or kerosene. When charcoal is produced in large quantities, as it is in Africa, the net warming effect can exceed the impact from the "modern energy sector" (transportation and industry) by 50-100 percent, even if charcoal is produced on a sustainable cycle so that all of the wood harvested for charcoal production is allowed to regenerate. However, while charcoal may be worse than firewood with respect to greenhouse gas emissions, it is an improvement with respect to exposure to health damaging pollutants, particularly particulate matter (PM). Levels of PM in households using charcoal are over 90 percent lower than households using open wood fires (316 -(159) mg/m3 for households using charcoal in a common improved stove compared to 3764 (360) mg/m3) for households using wood in open fires: mean (standard error)). These differences in exposure are consistent with 30 and 50 percent reductions in the incidence of acute respiratory infection (ARI) in adults and children under 5 respectively. Reconciling the costs and benefits of different household energy technologies creates a difficult policy challenge, particularly with the severe budgetary and resource constraints that household consumers and government agencies face in sub-Saharan Africa.

  16. The Spatial and Temporal Consumptive Water Use Impacts of Rapid Shale Gas Development and Use in Texas

    NASA Astrophysics Data System (ADS)

    Pacsi, A. P.; Allen, D.

    2013-12-01

    Over the past several years, the development of shale gas resources has proceeded rapidly in many areas of the United States, and this shale gas development requires the use of millions of gallons of water, per well, for hydraulic fracturing. Recent life cycle assessments of natural gas from shale formations have calculated the potential for water use reduction when water use is integrated along the entire natural gas supply chain, if the shale gas is used in natural-gas power plants to displace coal-fired electricity generation. Actual grid operation, however, is more complicated and would require both that sufficient unused natural gas generation capacity exists for the displacement of coal-fired power generation and that the natural gas price is low enough that the switching is financially feasible. In addition, water savings, which would occur mainly from a reduction in the cooling water demand at coal-fired power plants, may occur in different regions and at different times than water used in natural gas production. Thus, consumptive water impacts may be spatial and temporally disparate, which is not a consideration in current life-cycle literature. The development of shale gas resources in Texas in August 2008 through December 2009 was chosen as a case study for characterizing this phenomenon since Texas accounted for two-thirds of the shale gas produced in the United States during this period and since the price of natural gas for electricity generation dropped significantly over the episode. Changes to the Texas self-contained electric grid (ERCOT) for a scenario with actual natural gas production and prices was estimated using a constrained grid model, rather than assuming that natural gas generation would displace coal-fired power plant usage. The actual development scenario was compared to an alternative development scenario in which natural gas prices remained elevated throughout the episode. Upstream changes in water consumption from lignite (coal) mining and natural gas production in Texas were also estimated, and water consumption was aggregated by river basin for spatial resolution. Temporal results indicated that the development of shale gas resources during the episode led to a net reduction in consumptive water use in Texas but that a lag time existed before the water use in natural gas production regions was offset by changes in the electricity generation and lignite mining sectors. The water impact on specific river basins in production regions was varied. Some river basins had sufficient changes in coal-fired power plant generation to offset increased water use in shale gas production and for cooling at natural-gas fired power plants, while others did not. Thus, some areas have likely experienced increased water use due to shale gas production despite overall reductions in life-cycle consumptive water use in the state. The largest consumptive water use increase for a river basin, however, was less than 1% of its total water consumption.

  17. Analyzing the Impact of Residential Building Attributes, Demographic and Behavioral Factors on Natural Gas Usage

    SciTech Connect

    Livingston, Olga V.; Cort, Katherine A.

    2011-03-03

    This analysis examines the relationship between energy demand and residential building attributes, demographic characteristics, and behavioral variables using the U.S. Department of Energy’s Residential Energy Consumption Survey 2005 microdata. This study investigates the applicability of the smooth backfitting estimator to statistical analysis of residential energy consumption via nonparametric regression. The methodology utilized in the study extends nonparametric additive regression via local linear smooth backfitting to categorical variables. The conventional methods used for analyzing residential energy consumption are econometric modeling and engineering simulations. This study suggests an econometric approach that can be utilized in combination with simulation results. A common weakness of previously used econometric models is a very high likelihood that any suggested parametric relationships will be misspecified. Nonparametric modeling does not have this drawback. Its flexibility allows for uncovering more complex relationships between energy use and the explanatory variables than can possibly be achieved by parametric models. Traditionally, building simulation models overestimated the effects of energy efficiency measures when compared to actual "as-built" observed savings. While focusing on technical efficiency, they do not account for behavioral or market effects. The magnitude of behavioral or market effects may have a substantial influence on the final energy savings resulting from implementation of various energy conservation measures and programs. Moreover, variability in behavioral aspects and user characteristics appears to have a significant impact on total energy consumption. Inaccurate estimates of energy consumption and potential savings also impact investment decisions. The existing modeling literature, whether it relies on parametric specifications or engineering simulation, does not accommodate inclusion of a behavioral component. This study attempts to bridge that gap by analyzing behavioral data and investigate the applicability of additive nonparametric regression to this task. This study evaluates the impact of 31 regressors on residential natural gas usage. The regressors include weather, economic variables, demographic and behavioral characteristics, and building attributes related to energy use. In general, most of the regression results were in line with previous engineering and economic studies in this area. There were, however, some counterintuitive results, particularly with regard to thermostat controls and behaviors. There are a number of possible reasons for these counterintuitive results including the inability to control for regional climate variability due to the data sanitization (to prevent identification of respondents), inaccurate data caused by to self-reporting, and the fact that not all relevant behavioral variables were included in the data set, so we were not able to control for them in the study. The results of this analysis could be used as an in-sample prediction for approximating energy demand of a residential building whose characteristics are described by the regressors in this analysis, but a certain combination of their particular values does not exist in the real world. In addition, this study has potential applications for benefit-cost analysis of residential upgrades and retrofits under a fixed budget, because the results of this study contain information on how natural gas consumption might change once a particular characteristic or attribute is altered. Finally, the results of this study can help establish a relationship between natural gas consumption and changes in behavior of occupants.

  18. Reducing Onshore Natural Gas and Oil Exploration and Production Impacts Using a Broad-Based Stakeholder Approach

    SciTech Connect

    Amy Childers

    2011-03-30

    Never before has the reduction of oil and gas exploration and production impacts been as important as it is today for operators, regulators, non-governmental organizations and individual landowners. Collectively, these stakeholders are keenly interested in the potential benefits from implementing effective environmental impact reducing technologies and practices. This research project strived to gain input and insight from such a broad array of stakeholders in order to identify approaches with the potential to satisfy their diverse objectives. The research team examined three of the most vital issue categories facing onshore domestic production today: (1) surface damages including development in urbanized areas, (2) impacts to wildlife (specifically greater sage grouse), and (3) air pollution, including its potential contribution to global climate change. The result of the research project is a LINGO (Low Impact Natural Gas and Oil) handbook outlining approaches aimed at avoiding, minimizing, or mitigating environmental impacts. The handbook identifies technical solutions and approaches which can be implemented in a practical and feasible manner to simultaneously achieve a legitimate balance between environmental protection and fluid mineral development. It is anticipated that the results of this research will facilitate informed planning and decision making by management agencies as well as producers of oil and natural gas. In 2008, a supplemental task was added for the researchers to undertake a 'Basin Initiative Study' that examines undeveloped and/or underdeveloped oil and natural gas resources on a regional or geologic basin scope to stimulate more widespread awareness and development of domestic resources. Researchers assessed multi-state basins (or plays), exploring state initiatives, state-industry partnerships and developing strategies to increase U.S. oil and gas supplies while accomplishing regional economic and environmental goals.

  19. Volcanic gas emissions and their impact on ambient air character at Kilauea Volcano, Hawaii

    SciTech Connect

    Sutton, A.J.; Elias, T.; Navarrete, R.

    1994-12-31

    Gas emissions from Kilauea occur from the summit caldera, along the middle East Rift Zone (ERZ), and where lava enters the ocean. We estimate that the current ERZ eruption of Kilauea releases between 400 metric tonnes of SO{sub 2} per day, during eruptive pauses, to as much as 1850 metric tonnes per day during actively erupting periods, along with lesser amounts of other chemically and radiatively active species including H{sub 2}S, HCl and HF. In order to characterize gas emissions from Kilauea in a meaningful way for assessing environmental impact, we made a series of replicate grab-sample measurements of ambient air and precipitation at the summit of Kilauea, along its ERZ, and at coastal sites where lava enters the ocean. The grab-sampling data combined with SO{sub 2} emission rates, and continuous air quality and meteorological monitoring at the summit of Kilauea show that the effects of these emissions on ambient air character are a complex function of chemical reactivity, source geometry and effusivity, and local meteorology. Prevailing tradewinds typically carry the gases and aerosols released to the southwest, where they are further distributed by the regional wind regime. Episodes of kona, or low speed variable winds sometimes disrupt this pattern, however, and allow the gases and their oxidation products to collect at the summit and eastern side of the island. Summit solfatara areas of Kilauea are distinguished by moderate to high ambient SO{sub 2}, high H{sub 2}S at one location, and low H{sub 2}S at all others, and negligible HCl concentrations, as measured 1 m from degassing point-sources. Summit solfatara rain water has high sulfate and low chloride ion concentrations, and low pH.

  20. Assessment of the impact of the next generation solvent on DWPF melter off-gas flammability

    SciTech Connect

    Daniel, W. E.

    2013-02-13

    An assessment has been made to evaluate the impact on the DWPF melter off-gas flammability of replacing the current solvent used in the Modular Caustic-Side Solvent Extraction Process Unit (MCU) process with the Next Generation Solvent (NGS-MCU) and blended solvent. The results of this study showed that the concentrations of nonvolatile carbon and hydrogen of the current solvent in the Slurry Mix Evaporator (SME) product would both be about 29% higher than their counterparts of the NGS-MCU and blended solvent in the absence of guanidine partitioning. When 6 ppm of guanidine (TiDG) was added to the effluent transfer to DWPF to simulate partitioning for the NGS-MCU and blended solvent cases and the concentration of Isopar{reg_sign} L in the effluent transfer was controlled below 87 ppm, the concentrations of nonvolatile carbon and hydrogen of the NGS-MCU and blended solvent were still about 12% and 4% lower, respectively, than those of the current solvent. It is, therefore, concluded that as long as the volume of MCU effluent transfer to DWPF is limited to 15,000 gallons per Sludge Receipt and Adjustment Tank (SRAT)/SME cycle and the concentration of Isopar{reg_sign} L in the effluent transfer is controlled below 87 ppm, using the current solvent assumption of 105 ppm Isopar{reg_sign} L or 150 ppm solvent in lieu of NGS-MCU or blended solvent in the DWPF melter off-gas flammability assessment is conservative for up to an additional 6 ppm of TiDG in the effluent due to guanidine partitioning. This report documents the calculations performed to reach this conclusion.

  1. Quantitative fluid inclusion gas analysis of airburst, nuclear, impact and fulgurite glasses.

    SciTech Connect

    Parnell, John; Newsom, Horton E.; Blamey, Nigel J. F.; Boslough, Mark Bruce Elrick

    2010-10-01

    We present quantitative fluid inclusion gas analysis on a suite of violently-formed glasses. We used the incremental crush mass spectrometry method (Norman & Blamey, 2001) to analyze eight pieces of Libyan Desert Glass (LDG). As potential analogues we also analyzed trinitite, three impact crater glasses, and three fulgurites. The 'clear' LDG has the lowest CO{sub 2} content and O{sub 2}/Ar ratios are two orders of magnitude lower than atmospheric. The 'foamy' glass samples have heterogeneous CO{sub 2} contents and O{sub 2}/Ar ratios. N{sub 2}/Ar ratios are similar to atmospheric (83.6). H{sub 2} and He are elevated but it is difficult to confirm whether they are of terrestrial or meteoritic origin. Combustion cannot account for oxygen depletion that matches the amount of CO{sub 2} produced. An alternative mechanism is required that removes oxygen without producing CO{sub 2}. Trinitite has exceedingly high CO{sub 2} which we attribute to carbonate breakdown of the caliche at ground zero. The O{sub 2}/Ar ratio for trinitite is lower than atmospheric but higher than all LDG samples. N{sub 2}/Ar ratios closely match atmospheric. Samples from Lonar, Henbury and Aouelloul impact craters have atmospheric N{sub 2}/Ar ratios. O{sub 2}/Ar ratios at Lonar and Henbury are 9.5 to 9.9 whereas the O{sub 2}/Ar ratio is 0.1 for the Aouelloul sample. In most fulgurites the N{sub 2}/Ar ratio is higher than atmospheric, possibly due to interference from CO. Oxygen ranges from 1.3 to 19.3%. Gas signatures of LDG inclusions neither match those from the craters, trinitite nor fulgurites. It is difficult to explain both the observed depletion of oxygen in the LDG and a CO{sub 2} level that is lower than it would be if the CO{sub 2} were simply a product of hydrocarbon combustion in air. One possible mechanism for oxygen depletion is that as air turbulently mixed with a hot jet of vaporized asteroid from an airburst and expanded, the atmospheric oxygen reacted with the metal vapor to form metal oxides that condensed. This observation is compatible with the model of Boslough & Crawford (2008) who suggest that an airburst incinerates organic materials over a large area, melting surface materials that then quench to form glass. Bubbles would contain a mixture of pre-existing atmosphere with combustion products from organic material and products of the reaction between vaporized cosmic materials (including metals) and terrestrial surface and atmosphere.

  2. Impact of chemically amended pig slurry on greenhouse gas emissions, soil properties and leachate.

    PubMed

    O' Flynn, Cornelius J; Healy, Mark G; Lanigan, Gary J; Troy, Shane M; Somers, Cathal; Fenton, Owen

    2013-10-15

    The effectiveness of chemical amendment of pig slurry to ameliorate phosphorus (P) losses in runoff is well studied, but research mainly has concentrated only on the runoff pathway. The aims of this study were to investigate changes to leachate nutrient losses, soil properties and greenhouse gas (GHG) emissions due to the chemical amendment of pig slurry spread at 19kg total phosphorus (TP), 90kg total nitrogen (TN), and 180kg total carbon (TC) ha(-1). The amendments examined were: (1) commercial grade liquid alum (8% Al2O3) applied at a rate of 0.88:1 [Al:TP], (2) commercial-grade liquid ferric chloride (38% FeCl3) applied at a rate of 0.89:1 [Fe:TP] and (3) commercial-grade liquid poly-aluminium chloride (PAC) (10% Al2O3) applied at a rate of 0.72:1 [Al:TP]. Columns filled with sieved soil were incubated for 8mo at 10C and were leached with 160mL (19mm) distilled water wk(-1). All amendments reduced the Morgan's phosphorus and water extractable P content of the soil to that of the soil-only treatment, indicating that they have the ability to reduce P loss in leachate following slurry application. There were no significant differences between treatments for nitrogen (N) or carbon (C) in leachate or soil, indicating no deleterious impact on reactive N emissions or soil C cycling. Chemical amendment posed no significant change to GHG emissions from pig slurry, and in the cases of alum and PAC, reduced cumulative N2O and CO2 losses. Chemical amendment of land applied pig slurry can reduce P in runoff without any negative impact on nutrient leaching and GHG emissions. Future work must be conducted to ascertain if more significant reductions in GHG emissions are possible with chemical amendments. PMID:23850764

  3. Determining air quality and greenhouse gas impacts of hydrogen infrastructure and fuel cell vehicles.

    PubMed

    Stephens-Romero, Shane; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald; Samuelsen, Scott

    2009-12-01

    Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 mug/m(3) in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario). PMID:19943683

  4. Greenhouse gas emission impacts of alternative-fueled vehicles: Near-term vs. long-term technology options

    SciTech Connect

    Wang, M.Q.

    1997-05-20

    Alternative-fueled vehicle technologies have been promoted and used for reducing petroleum use, urban air pollution, and greenhouse gas emissions. In this paper, greenhouse gas emission impacts of near-term and long-term light-duty alternative-fueled vehicle technologies are evaluated. Near-term technologies, available now, include vehicles fueled with M85 (85% methanol and 15% gasoline by volume), E85 (85% ethanol that is produced from corn and 15% gasoline by volume), compressed natural gas, and liquefied petroleum gas. Long-term technologies, assumed to be available around the year 2010, include battery-powered electric vehicles, hybrid electric vehicles, vehicles fueled with E85 (ethanol produced from biomass), and fuel-cell vehicles fueled with hydrogen or methanol. The near-term technologies are found to have small to moderate effects on vehicle greenhouse gas emissions. On the other hand, the long-term technologies, especially those using renewable energy (such as biomass and solar energy), have great potential for reducing vehicle greenhouse gas emissions. In order to realize this greenhouse gas emission reduction potential, R and D efforts must continue on the long-term technology options so that they can compete successfully with conventional vehicle technology.

  5. The Impact of a Lower Sea Ice Extent on Arctic Greenhouse Gas Exchange

    NASA Astrophysics Data System (ADS)

    Parmentier, Frans-Jan W.; Christensen, Torben R.; Lotte Sørensen, Lise; Rysgaard, Søren; McGuire, A. David; Miller, Paul A.; Walker, Donald A.

    2013-04-01

    Arctic sea ice extent hit a new record low in September 2012, when it fell to a level about two times lower than the 1979-2000 average. Record low sea ice extents such as these are often hailed as an obvious example of the impact of climate change on the Arctic. Less obvious, however, are the further implications of a lower sea ice extent on Arctic greenhouse gas exchange. For example, a reduction in sea ice, in consort with a lower snow cover, has been connected to higher surface temperatures in the terrestrial part of the Arctic (Screen et al., 2012). These higher temperatures and longer growing seasons have the potential to alter the CO2 balance of Arctic tundra through enhanced photosynthesis and respiration, as well as the magnitude of methane emissions. In fact, large changes are already observed in terrestrial ecosystems (Post et al., 2009), and concerns have been raised of large releases of carbon through permafrost thaw (Schuur et al., 2011). While these changes in the greenhouse gas balance of the terrestrial Arctic are described in numerous studies, a connection with a decline in sea ice extent is nonetheless seldom made. In addition to these changes on land, a lower sea ice extent also has a direct effect on the exchange of greenhouse gases between the ocean and the atmosphere. For example, due to sea ice retreat, more ocean surface remains in contact with the atmosphere, and this has been suggested to increase the oceanic uptake of CO2 (Bates et al., 2006). However, the sustainability of this increased uptake is uncertain (Cai et al., 2010), and carbon fluxes related directly to the sea ice itself add much uncertainty to the oceanic uptake of CO2 (Nomura et al., 2006; Rysgaard et al., 2007). Furthermore, significant emissions of methane from the Arctic Ocean have been observed (Kort et al., 2012; Shakhova et al., 2010), but the consequence of a lower sea ice extent thereon is still unclear. Overall, the decline in sea ice that has been seen in recent years has the potential to influence greenhouse gas exchange across terrestrial ecosystems and the Arctic Ocean, but the overall impact remains unclear. In this study, we therefore try to reduce this uncertainty by addressing the influence of the decline in sea ice extent on all affected greenhouse gas fluxes in the high latitudes. Also, we will address the need for more research, on the ocean and on the land, to understand the impact of a lower sea ice extent on Arctic greenhouse gas exchange. References: Bates, N. R., Moran, S. B., Hansell, D. A. and Mathis, J. T.: An increasing CO2 sink in the Arctic Ocean due to sea-ice loss, Geophys. Res. Lett., 33, L23609, doi:10.1029/2006GL027028, 2006. Cai, W.-J., Chen, L., Chen, B., Gao, Z., Lee, S. H., Chen, J., Pierrot, D., Sullivan, K., Wang, Y., Hu, X., Huang, W.-J., et al.: Decrease in the CO2 Uptake Capacity in an Ice-Free Arctic Ocean Basin, Science, 329(5991), 556-559, doi:10.1126/science.1189338, 2010. Kort, E. A., Wofsy, S. C., Daube, B. C., Diao, M., Elkins, J. W., Gao, R. S., Hintsa, E. J., Hurst, D. F., Jimenez, R., Moore, F. L., Spackman, J. R., et al.: Atmospheric observations of Arctic Ocean methane emissions up to 82 degrees north, Nature Geosci., 5(5), 318-321, doi:10.1038/NGEO1452, 2012. Nomura, D., Yoshikawa-Inoue, H. and Toyota, T.: The effect of sea-ice growth on air-sea CO2 flux in a tank experiment, vol. 58, pp. 418-426. 2006. Post, E., Forchhammer, M. C., Bret-Harte, M. S., Callaghan, T. V., Christensen, T. R., Elberling, B., Fox, A. D., Gilg, O., Hik, D. S., Høye, T. T., Ims, R. A., et al.: Ecological Dynamics Across the Arctic Associated with Recent Climate Change, Science, 325(5946), 1355-1358, doi:10.1126/science.1173113, 2009. Rysgaard, S., Glud, R. N., Sejr, M. K., Bendtsen, J. and Christensen, P. B.: Inorganic carbon transport during sea ice growth and decay: A carbon pump in polar seas, J. Geophys. Res., 112, C03016, doi:10.1029/2006JC003572, 2007. Schuur, E. A. G., Abbott, B. and Network, P. C.: High risk of permafrost thaw, Nature, 480(7375), 32-33, 2011. Screen, J. A., Deser, C. and Simmonds, I.: Local and remote controls on observed Arctic warming, Geophys. Res. Lett., 39, L10709, doi:10.1029/2012GL051598, 2012. Shakhova, N., Semiletov, I., Salyuk, A., Yusupov, V., Kosmach, D. and Gustafsson, O.: Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf, Science, 327(5970), 1246-1250, doi:10.1126/science.1182221, 2010.

  6. Impact of Asphaltenes and Resins on the Wetting Characteristics of Tars at Former Manufactured Gas Plants

    NASA Astrophysics Data System (ADS)

    Hauswirth, S. C.; Birak, P. S.; Rylander, S.; Pedit, J. A.; Miller, C. T.

    2008-12-01

    Tars produced as a byproduct of coal and oil gasification at manufactured gas plants (MGPs) during the 19th and early 20th centuries were often released into the environment through poor disposal practices or leaks in holding tanks and piping. These tars are persistent contaminants, leaching polycyclic aromatic hydrocarbons (PAHs) into groundwater and posing a significant risk to human and ecological health. MGP tars also have several properties that make them notoriously difficult to remediate. They are denser than water, so they can migrate to depths which make direct removal difficult or impossible, and their relatively high viscosities and ability to alter the wetting characteristics of porous media result in inefficient removal by traditional pump-and-treat methods. In this study, we investigate the last of these properties. Previous studies have linked wetting changes to asphaltenes---polar, high molecular weight compounds present in the tars. However, we have conducted qualitative bottle tests for tar samples collected from two former MGPs which indicate that there is no direct correlation between asphaltene concentration and the tendency to alter wetting characteristics of porous media. To better understand the factors controlling wetting behavior, we isolate asphaltenes and resins, another class of polar compounds, from a tar sample and recombine them with the remaining PAH mixture to create a series of tars of varying composition. We assess the relative impact of each of the fractions on wettability through contact angle measurements conducted at three different pHs.

  7. Impacts of Vehicle Weight Reduction via Material Substitution on Life-Cycle Greenhouse Gas Emissions.

    PubMed

    Kelly, Jarod C; Sullivan, John L; Burnham, Andrew; Elgowainy, Amgad

    2015-10-20

    This study examines the vehicle-cycle and vehicle total life-cycle impacts of substituting lightweight materials into vehicles. We determine part-based greenhouse gas (GHG) emission ratios by collecting material substitution data and evaluating that alongside known mass-based GHG ratios (using and updating Argonne National Laboratory's GREET model) associated with material pair substitutions. Several vehicle parts are lightweighted via material substitution, using substitution ratios from a U.S. Department of Energy report, to determine GHG emissions. We then examine fuel-cycle GHG reductions from lightweighting. The fuel reduction value methodology is applied using FRV estimates of 0.15-0.25, and 0.25-0.5 L/(100km100 kg), with and without powertrain adjustments, respectively. GHG breakeven values are derived for both driving distance and material substitution ratio. While material substitution can reduce vehicle weight, it often increases vehicle-cycle GHGs. It is likely that replacing steel (the dominant vehicle material) with wrought aluminum, carbon fiber reinforced plastic (CRFP), or magnesium will increase vehicle-cycle GHGs. However, lifetime fuel economy benefits often outweigh the vehicle-cycle, resulting in a net total life-cycle GHG benefit. This is the case for steel replaced by wrought aluminum in all assumed cases, and for CFRP and magnesium except for high substitution ratio and low FRV. PMID:26393414

  8. Modeling impacts of farming management practices on greenhouse gas emissions in the oasis region of China

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Sun, G. J.; Zhang, F.; Qi, J.; Zhao, C. Y.

    2011-08-01

    Agricultural ecosystems are major sources of greenhouse gas (GHG) emissions, specifically nitrous oxide (N2O) and carbon dioxide (CO2). An important method of investigating GHG emissions in agricultural ecosystems is model simulation. Field measurements quantifying N2O and CO2 fluxes were taken in a summer maize ecosystem in Zhangye City, Gansu Province, in northwestern China in 2010. Observed N2O and CO2 fluxes were used for validating flux predictions by a DeNitrification-DeComposition (DNDC) model. Then sensitivity tests on the validated DNDC model were carried out on three variables: climatic factors, soil properties and agricultural management. Results indicated that: (1) the factors that N2O emissions were sensitive to included nitrogen fertilizer application rate, manure amendment and residue return rate; (2) CO2 emission increased with increasing manure amendment, residue return rate and initial soil organic carbon (SOC); and (3) net global warming potential (GWP) increased with increasing N fertilizer application rate and decreased with manure amendment, residue return rate and precipitation increase. Simulation of the long-term impact on SOC, N2O and net GWP emissions over 100 yr of management led to the conclusion that increasing residue return rate is a more efficient method of mitigating GHG emission than increasing fertilizer N application rate in the study area.

  9. Impact of the Keystone XL pipeline on global oil markets and greenhouse gas emissions

    NASA Astrophysics Data System (ADS)

    Erickson, Peter; Lazarus, Michael

    2014-09-01

    Climate policy and analysis often focus on energy production and consumption, but seldom consider how energy transportation infrastructure shapes energy systems. US President Obama has recently brought these issues to the fore, stating that he would only approve the Keystone XL pipeline, connecting Canadian oil sands with US refineries and ports, if it `does not significantly exacerbate the problem of carbon pollution'. Here, we apply a simple model to understand the implications of the pipeline for greenhouse gas emissions as a function of any resulting increase in oil sands production. We find that for every barrel of increased production, global oil consumption would increase 0.6 barrels owing to the incremental decrease in global oil prices. As a result, and depending on the extent to which the pipeline leads to greater oil sands production, the net annual impact of Keystone XL could range from virtually none to 110 million tons CO2 equivalent annually. This spread is four times wider than found by the US State Department (1-27 million tons CO2e), who did not account for global oil market effects. The approach used here, common in lifecycle analysis, could also be applied to other pending fossil fuel extraction and supply infrastructure.

  10. Impact of policy on greenhouse gas emissions and economics of biodiesel production.

    PubMed

    Olivetti, Elsa; Gl?en, Ece; Mala, Joo; Castanheira, Erica; Freire, Fausto; Dias, Luis; Kirchain, Randolph

    2014-07-01

    As an alternative transportation fuel to petrodiesel, biodiesel has been promoted within national energy portfolio targets across the world. Early estimations of low lifecycle greenhouse gas (GHG) emissions of biodiesel were a driver behind extensive government support in the form of financial incentives for the industry. However, studies consistently report a high degree of uncertainty in these emissions estimates, raising questions concerning the carbon benefits of biodiesel. Furthermore, the implications of feedstock blending on GHG emissions uncertainty have not been explicitly addressed despite broad practice by the industry to meet fuel quality standards and to control costs. This work investigated the impact of feedstock blending on the characteristics of biodiesel by using a chance-constrained (CC) blend optimization method. The objective of the optimization is minimization of feedstock costs subject to fuel standards and emissions constraints. Results indicate that blending can be used to manage GHG emissions uncertainty characteristics of biodiesel, and to achieve cost reductions through feedstock diversification. Simulations suggest that emissions control policies that restrict the use of certain feedstocks based on their GHG estimates overlook blending practices and benefits, increasing the cost of biodiesel. In contrast, emissions control policies which recognize the multifeedstock nature of biodiesel provide producers with feedstock selection flexibility, enabling them to manage their blend portfolios cost effectively, potentially without compromising fuel quality or emissions reductions. PMID:24828402

  11. Climate impacts of air quality policy: switching to a natural gas-fueled public transportation system in New Delhi.

    PubMed

    Reynolds, Conor C O; Kandlikar, Milind

    2008-08-15

    Between 2001 and 2003, public transport vehicles in New Delhi were required to switch their fuel to natural gas in an attemptto reduce their air pollution impacts. This study examines the climatic impacts of New Delhi's fuel switching policy, and outlines implications for such efforts in rapidly industrializing countries. Natural gas is mostly composed of methane, an important greenhouse gas. Emitted aerosols (black carbon, particulate organic carbon, and sulfate) also cause radiative forcing. We find that methane and black carbon emissions are critical contributors to the change in carbon dioxide equivalent [CO2(e)] emissions. In New Delhi, the switch to natural gas results in a 30% increase in CO2(e) when the impact of aerosols is not considered. However, when aerosol emissions are taken into account in our model, the net effect of the switch is estimated to be a 10% reduction in CO2(e), and there may be as much as a 30% reduction in CO2(e). There is significant potential for emissions reductions through the United Nations Framework Convention on Climate Change (UNFCCC) Clean Development Mechanism for such fuel switching projects. PMID:18767636

  12. Characterization of VOCs Across Pennsylvania: Assessing Emissions from Rural, Forested, Agricultural and Natural Gas Drilling-Impacted Areas

    NASA Astrophysics Data System (ADS)

    Grannas, A. M.; Fuentes, J. D.; Ramos-Garcs, F.; Wang, D. K.; Martins, D. K.

    2012-12-01

    Volatile organic compounds (VOCs) of both biogenic and anthropogenic origin are important to troposphere chemistry, particularly the formation of photochemical smog and secondary organic aerosol. There is concern that increased natural gas exploration may lead to increased emissions of certain VOCs during well development and due to fugitive emissions from operational well sites and pipelines. For a six-day period in June 2012, a variety of VOCs were measured using canister sampling from a mobile measurement platform. Transects from southwestern to northeastern Pennsylvania were studied, with samples obtained in rural, forested, urban, farm-impacted and gas well-impacted sites. As expected, biogenic VOCs and isoprene oxidation products were enhanced in forested regions, while anthropogenic non-methane hydrocarbons were enhanced in urban areas. BTEX (benzene, toluene, ethylbenzene and xylenes) was enhanced in urban areas, but the concentrations of BTEX measured near developing and existing natural gas sites were similar to rural and forested sites. Halogenated hydrocarbons and Freon compounds were consistent at all site locations. We will discuss the specific concentrations and signatures of these compounds and assess the potential impact of agricultural activities and gas well development on the observed VOC concentrations and variability.

  13. Climate Change Impacts on US Agriculture and the Benefits of Greenhouse Gas Mitigation

    NASA Astrophysics Data System (ADS)

    Monier, E.; Sue Wing, I.; Stern, A.

    2014-12-01

    As contributors to the US EPA's Climate Impacts and Risk Assessment (CIRA) project, we present empirically-based projections of climate change impacts on the yields of five major US crops. Our analysis uses a 15-member ensemble of climate simulations using the MIT Integrated Global System Model (IGSM) linked to the NCAR Community Atmosphere Model (CAM), forced by 3 emissions scenarios (a "business as usual" reference scenario and two stabilization scenarios at 4.5W/m2 and 3.7 W/m2 by 2100), quantify the agricultural impacts avoided due to greenhouse gas emission reductions. Our innovation is the coupling of climate model outputs with empirical estimates of the long-run relationship between crop yields and temperature, precipitation and soil moisture derived from the co-variation between yields and weather across US counties over the last 50 years. Our identifying assumption is that since farmers' planting, management and harvesting decisions are based on land quality and expectations of weather, yields and meteorological variables share a long-run equilibrium relationship. In any given year, weather shocks cause yields to diverge from their expected long-run values, prompting farmers to revise their long-run expectations. We specify a dynamic panel error correction model (ECM) that statistically distinguishes these two processes. The ECM is estimated for maize, wheat, soybeans, sorghum and cotton using longitudinal data on production and harvested area for ~1,100 counties from 1948-2010, in conjunction with spatial fields of 3-hourly temperature, precipitation and soil moisture from the Global Land Data Assimilation System (GLDAS) forcing and output files, binned into annual counts of exposure over the growing season and mapped to county centroids. For scenarios of future warming the identical method was used to calculate counties' current (1986-2010) and future (2036-65 and 2086-2110) distributions of simulated 3-hourly growing season temperature, precipitation and soil moisture. Finally, we combine these variables with the fitted long-run response to obtain county-level yields under current average climate and projected future climate under our three warming scenarios. We close our presentation with a discussion of the implications for mitigation and adaptation decisions.

  14. Impact of Unconventional Shale Gas Waste Water Disposal on Surficial Streams

    NASA Astrophysics Data System (ADS)

    Cozzarelli, I.; Akob, D.; Mumford, A. C.

    2014-12-01

    The development of unconventional natural gas resources has been rapidly increasing in recent years, however, the environmental impacts and risks are not yet well understood. A single well can generate up to 5 million L of produced water (PW) consisting of a blend of the injected fluid and brine from a shale formation. With thousands of wells completed in the past decade, the scope of the challenge posed in the management of this wastewater becomes apparent. The USGS Toxic Substances Hydrology Program is studying both intentional and unintentional releases of PW and waste solids. One method for the disposal of PW is underground injection; we are assessing the potential risks of this method through an intensive, interdisciplinary study at an injection disposal facility in the Wolf Creek watershed in WV. Disposal of PW via injection begun in 2002, with over 5.5 mil. L of PW injected to date. The facility consists of the injection well, a tank farm, and two former holding ponds (remediated in early 2014) and is bordered by two small tributaries of Wolf Creek. Water and sediments were acquired from these streams in June 2014, including sites upstream, within, and downstream from the facility. We are analyzing aqueous and solid phase geochemistry, mineralogy, hydrocarbon content, microbial community composition, and potential toxicity. Field measurements indicated that conductivity downstream (416 μS/cm) was elevated in comparison to upstream (74 μS/cm) waters. Preliminary data indicated elevated Cl- (115 mg/L) and Br- (0.88 mg/L) concentrations downstream, compared to 0.88 mg/L Cl- and <0.03 mg/L Br- upstream of the facility. Because elevated TDS is a marker of PW, these data provide a first indication that PW from the facility is impacting nearby streams. In addition, total Fe concentrations downstream were 8.1 mg/L, far in excess of the 0.13 mg/L found upstream from the facility, suggesting the potential for microbial Fe cycling. We are conducting a broad suite of experiments to assess the potential for microbial metabolism of the organic components of PW, and to determine the effects of this metabolism on the geochemistry of the site. We anticipate that this study will prove to be a useful model for the potential impact of a PW disposal facility on adjoining surface- and shallow groundwater.

  15. Comparing Statewide Economic Impacts of New Generation from Wind, Coal, and Natural Gas in Arizona, Colorado, and Michigan: Preprint

    SciTech Connect

    Tegen, S.

    2005-08-01

    With increasing concerns about energy independence, job outsourcing, and risks of global climate change, it is important for policy makers to understand all impacts from their decisions about energy resources. This paper assesses one aspect of the impacts: direct economic effects. The paper compares impacts to states from equivalent new electrical generation from wind, natural gas, and coal. Economic impacts include materials and labor for construction, operations, maintenance, fuel extraction, and fuel transport, as well as project financing, property tax, and landowner revenues. We examine spending on plant construction during construction years, in addition to all other operational expenditures over a 20-year span. Initial results indicate that adding new wind power can be more economically effective than adding new gas or coal power, and that a higher percentage of dollars spent on coal and gas will leave the state. For this report, we interviewed industry representatives and energy experts, in addition to consulting government documents, models, and existing literature. The methodology for this research can be adapted to other contexts for determining economic effects of new power generation in other states and regions.

  16. Comparing Statewide Economic Impacts of New Generation from Wind, Coal, and Natural Gas in Arizona, Colorado, and Michigan

    SciTech Connect

    Tegen, S.

    2006-05-01

    With increasing concerns about energy independence, job outsourcing, and risks of global climate change, it is important for policy makers to understand all impacts from their decisions about energy resources. This paper assesses one aspect of the impacts: direct economic effects. The paper compares impacts to states from equivalent new electrical generation from wind, natural gas, and coal. Economic impacts include materials and labor for construction, operations, maintenance, fuel extraction, and fuel transport, as well as project financing, property tax, and landowner revenues. We examine spending on plant construction during construction years, in addition to all other operational expenditures over a 20-year span. Initial results indicate that adding new wind power can be more economically effective than adding new gas or coal power and that a higher percentage of dollars spent on coal and gas will leave the state. For this report, we interviewed industry representatives and energy experts, in addition to consulting government documents, models, and existing literature. The methodology for this research can be adapted to other contexts for determining economic effects of new power generation in other states and regions.

  17. 75 FR 37749 - White River National Forest, Colorado, Oil and Gas Leasing Environmental Impact Statement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-30

    ... increasing rate of oil and gas development adjacent ] to and on the WRNF, and a projection of substantial increase in oil and gas development on the WRNF. The EIS will address current applicable guidance, policy... projected oil and gas development activities on the WRNF. Consequently, the Forest Supervisor of the...

  18. The impact of a pulsing groundwater table on greenhouse gas emissions in riparian grey alder stands.

    PubMed

    Mander, Ülo; Maddison, Martin; Soosaar, Kaido; Teemusk, Alar; Kanal, Arno; Uri, Veiko; Truu, Jaak

    2015-02-01

    Floods control greenhouse gas (GHG) emissions in floodplains; however, there is a lack of data on the impact of short-term events on emissions. We studied the short-term effect of changing groundwater (GW) depth on the emission of (GHG) carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in two riparian grey alder (Alnus incana) stands of different age in Kambja, southern Estonia, using the opaque static chamber (five replicates in each site) and gas chromatography methods. The average carbon and total nitrogen content in the soil of the old alder (OA) stand was significantly higher than in the young alder (YA) stand. In both stands, one part was chosen for water table manipulation (Manip) and another remained unchanged with a stable and deeper GW table. Groundwater table manipulation (flooding) significantly increases CH4 emission (average: YA-Dry 468, YA-Manip 8,374, OA-Dry 468, OA-Manip 4,187 μg C m(-2) h(-1)) and decreases both CO2 (average: OA-Dry 138, OA-Manip 80 mg C m(-2) h(-1)) and N2O emissions (average: OA-Dry 23.1, OA-Manip 11.8 μg N m(-2) h(-1)) in OA sites. There was no significant difference in CO2 and CH4 emissions between the OA and YA sites, whereas in OA sites with higher N concentration in the soil, the N2O emission was significantly higher than at the YA sites. The relative CO2 and CH4 emissions (the soil C stock-related share of gaseous losses) were higher in manipulated plots showing the highest values in the YA-Manip plot (0.03 and 0.0030 % C day(-1), respectively). The soil N stock-related N2O emission was very low achieving 0.000019 % N day(-1) in the OA-Dry plot. Methane emission shows a negative correlation with GW, whereas the 20 cm depth is a significant limit below which most of the produced CH4 is oxidized. In terms of CO2 and N2O, the deeper GW table significantly increases emission. In riparian zones of headwater streams, the short-term floods (e.g. those driven by extreme climate events) may significantly enhance methane emission whereas the long-term lowering of the groundwater table is a more important initiator of N2O fluxes from riparian gley soils than flood pulses. PMID:25124475

  19. Health Impact Assessments, Regulation, and the Unconventional Gas Industry in the UK: Exploiting Resources, Ideology, and Expertise?

    PubMed

    Watterson, Andrew; Dinan, William

    2016-02-01

    Health impact assessments (HIAs) across the globe may be used by governments and industries to secure approval for unconventional gas extraction developments. HIA is an umbrella term that covers an array of health review and assessment practices, ranging from the very general to quite specific and technical health studies. Our concern in this paper is principally with the specialist end of the HIA continuum and particularly its application to unconventional gas extraction in the UK. We outline the context within which HIAs in unconventional gas extraction may be conducted. We then explain what HIAs may do. HIAs are often commissioned from consultancy companies to assess unconventional gas extraction project risks and benefits and propose mitigation measures. Communities can rarely afford HIAs in the planning process and may consider them biased when commissioned by vested interests. The oil and gas industry uses these techniques for its own ends. Hiring experts, be they specialist consultants, researchers, lobbyists, ex-government officials, or regulators, to influence planning and regulation is a well-tried tactic and structural advantage exploited by industry in seeking license to operate. Equitable and ethical HIA principles are urgently needed in the UK in relation to unconventional gas to secure the integrity and probity of the emerging regulatory system and address concerns regarding unregulated practitioners. PMID:26531123

  20. Long-term impacts of manure amendments on carbon andgreenhouse gas dynamics of rangelands.

    PubMed

    Owen, Justine J; Parton, William J; Silver, Whendee L

    2015-12-01

    Livestock manure is applied to rangelands as an organic fertilizer to stimulate forage production, but the long-term impacts of this practice on soil carbon (C) and greenhouse gas (GHG) dynamics are poorly known. We collected soil samples from manured and nonmanured fields on commercial dairies and found that manure amendments increased soil C stocks by 19.07.3MgCha(-1) and N stocks by 1.940.63MgNha(-1) compared to nonmanured fields (0-20cm depth). Long-term historical (1700-present) and future (present-2100) impacts of management on soil C and N dynamics, net primary productivity (NPP), and GHG emissions were modeled with DayCent. Modeled total soil C and N stocks increased with the onset of dairying. Nitrous oxide (N2 O) emissions also increased by ~2kg N2 O-Nha(-1) yr(-1) . These emissions were proportional to total N additions and offset 75-100% of soil C sequestration. All fields were small net methane (CH4 ) sinks, averaging -4.71.2kg CH4 -Cha(-1) yr(-1) . Overall, manured fields were net GHG sinks between 1954 and 2011 (-0.740.73Mg CO2 eha(-1) yr(-1) , CO2 e are carbon dioxide equivalents), whereas nonmanured fields varied around zero. Future soil C pools stabilized 40-60years faster in manured fields than nonmanured fields, at which point manured fields were significantly larger sources than nonmanured fields (1.450.52Mg CO2 eha(-1) yr(-1) and 0.510.60Mg CO2 eha(-1) yr(-1) , respectively). Modeling also revealed a large background loss of soil C from the passive soil pool associated with the shift from perennial to annual grasses, equivalent to 29.41.47 Tg CO2 e in California between 1820 and 2011. Manure applications increased NPP and soil C storage, but plant community changes and GHG emissions decreased, and eventually eliminated, the net climate benefit of this practice. PMID:26183573

  1. Greenhouse gas impacts of declining hydrocarbon resource quality: Depletion, dynamics, and process emissions

    NASA Astrophysics Data System (ADS)

    Brandt, Adam Robert

    This dissertation explores the environmental and economic impacts of the transition to hydrocarbon substitutes for conventional petroleum (SCPs). First, mathematical models of oil depletion are reviewed, including the Hubbert model, curve-fitting methods, simulation models, and economic models. The benefits and drawbacks of each method are outlined. I discuss the predictive value of the models and our ability to determine if one model type works best. I argue that forecasting oil depletion without also including substitution with SCPs results in unrealistic projections of future energy supply. I next use information theoretic techniques to test the Hubbert model of oil depletion against five other asymmetric and symmetric curve-fitting models using data from 139 oil producing regions. I also test the assumptions that production curves are symmetric and that production is more bell-shaped in larger regions. Results show that if symmetry is enforced, Gaussian production curves perform best, while if asymmetry is allowed, asymmetric exponential models prove most useful. I also find strong evidence for asymmetry: production declines are consistently less steep than inclines. In order to understand the impacts of oil depletion on GHG emissions, I developed the Regional Optimization Model for Emissions from Oil Substitutes (ROMEO). ROMEO is an economic optimization model of investment and production of fuels. Results indicate that incremental emissions (with demand held constant) from SCPs could be 5-20 GtC over the next 50 years. These results are sensitive to the endowment of conventional oil and not sensitive to a carbon tax. If demand can vary, total emissions could decline under a transition because the higher cost of SCPs lessens overall fuel consumption. Lastly, I study the energetic and environmental characteristics of the in situ conversion process, which utilizes electricity to generate liquid hydrocarbons from oil shale. I model the energy inputs and outputs from the ICP use them to calculate the GHG emissions from the ICP. Energy outputs (as refined liquid fuel) range from 1.2 to 1.6 times the total primary energy inputs. Well-to-tank greenhouse gas emissions range from 30.6 to 37.1 gCeq./MJ of final fuel delivered, 21 to 47% larger than those from conventionally produced petroleum-based fuels.

  2. Impact of exploratory offshore drilling on benthic communities in the Minerva gas field, Port Campbell, Australia.

    PubMed

    Currie, D R; Isaacs, Leanne R

    2005-04-01

    Changes to benthic infauna caused by exploratory gas drilling operations in the Minerva field were examined experimentally using a BACI (before, after, control, impact) design. Analysis of 72 x 0.1 m2 Smith-McIntyre grab samples obtained from one pre-drilling and three post-drilling periods yielded a diverse fauna consisting of 196 invertebrate species and 5035 individuals. Changes to benthic community structure were assessed using ANOVA and nonmetric multidimensional scaling (MDS). The abundances of two common species (Apseudes sp. 1 and Prionospio coorilla) decreased significantly at the well-head site immediately after drilling. The size of these reductions in abundance ranged between 71% and 88%, and persisted for less than 4 months after drilling. A third common species (Katlysia sp. 1) increased in abundance 200 m east of the well-head following drilling. Most species occurred at densities too low to be analysed individually and so were pooled at higher taxonomic levels. Changes in the abundance of species aggregated by phylum varied, but significant declines in the most abundant phyla (Crustaceans and Polychaetes) of 45-73% were observed at all sites within a 100 m radius of the well-head following drilling. In most cases these changes became undetectable four months after drilling following species recruitments. MDS ordinations confirm that drilling related changes to benthic community structure are most pronounced at stations located closest to the well-head. Additionally, the ordinations indicate that modified communities persist at the well-head for more than 11 months following exploratory drilling. PMID:15465131

  3. Quantitation of opioids in whole blood by electron impact-gas chromatography-mass spectrometry.

    PubMed

    Tiscione, Nicholas B; Shan, Xiaoqin; Alford, Ilene; Yeatman, Dustin Tate

    2011-03-01

    Opioids are frequently encountered in Forensic Toxicology casework. A PubMed literature search was conducted to find a method using electron impact-gas chromatography-mass spectrometry to examine whole blood specimens. A previously published method was identified, and an updated version was provided by the State of North Carolina Office of the Chief Medical Examiner. This procedure was used as a starting point for development and validation of a refined procedure to be used in the Palm Beach County Sheriff's Office Forensic Toxicology laboratory for routine analysis of antemortem forensic toxicology case samples. Materials and instrumentation common to most forensic toxicology laboratories were utilized while obtaining detection limits from 1 to 10 ng/mL and quantitation limits of 2.5 to 10 ng/mL using 1 mL of whole blood. Target compounds were chosen based on applicability to the method as well as availability and common use in the United States and include dihydrocodeine, codeine, morphine, hydrocodone, 6-monoacetylmorphine, hydromorphone, oxycodone, and oxymorphone. Each analyte demonstrated two zero-order linear ranges (r(2) > 0.990) over the concentrations evaluated (from 2.5 to 500 ng/mL). The coefficient of variation of replicate analyses was less than 12%. Quantitative accuracy was within 27% at 2.5 ng/mL, 11% at 10 ng/mL, and 8% at 50 ng/mL. The validated method provides a more sensitive procedure for the quantitation of common opioids in blood using standard laboratory equipment and a small amount of sample. PMID:21396229

  4. Impacts of mustard gas exposure on veterans mental health: A study on the role of education

    PubMed Central

    Karami, Gholam-Reza; Ameli, Javad; Roeintan, Rahim; Jonaidi-Jafari, Nematollah; Saburi, Amin

    2013-01-01

    Background: The mustard gas (MG) exposure can impair physical health and therefore increase the probability of the posttraumatic stress disorder (PTSD) and psychological disorders. Aim: The aim of this study was to investigate long-term effects of MG exposure on veterans mental health. Materials and Methods: This was a cross-sectional study. In order to assess prevalence of mental health and PTSD of 100 MG victims 25 years after the exposure to MG in Iran-Iraq conflict, the general health questionnaire (GHQ-28) and Impact of Event Scale-Revised, respectively was administered. Results: The mean (standard deviation (SD)) age of participants was 40.63 (5.86) years. The mean GHQ-28 (47.34) of the study group was higher compared to standardized cutoff point (23) of the Iranian community. Also, it was found that 38 participants (38%) suffer from PTSD. The results of this study showed that academic education in the PTSD group was less than that in the non-PTSD group (P=0.03). In addition, in multivariate analysis it was found that only education level of the veterans and their wives were effective on the mental health score (adjusted P=0.036 and 0.041, respectively). The mean score of depression and psychosocial activity subscale in patients at higher education level was lower than patients at lower education level (P<0.05). Conclusion: This study found that sulfur mustard (SM) exposure can be effect on mental health even 25 years after exposure. Therefore, the psychological state should be more considered in chemical injured veterans and it is important that providing more mental health centers for this community. PMID:24459369

  5. The impact of gas bulk rotation on the Lyα line

    SciTech Connect

    Garavito-Camargo, Juan N.; Forero-Romero, Jaime E.; Dijkstra, Mark E-mail: je.forero@uniandes.edu.co

    2014-11-10

    We present results of radiative transfer calculations to measure the impact of gas bulk rotation on the morphology of the Lyα emission line in distant galaxies. We model a galaxy as a sphere with an homogeneous mixture of dust and hydrogen at a constant temperature. These spheres undergo solid-body rotation with maximum velocities in the range 0-300 km s{sup –1} and neutral hydrogen optical depths in the range τ{sub H} = 10{sup 5}-10{sup 7}. We consider two types of source distributions in the sphere: central and homogeneous. Our main result is that rotation introduces a dependence of the line morphology with viewing angle and rotational velocity. Observations with a line of sight parallel to the rotation axis yield line morphologies similar to the static case. For lines of sight perpendicular to the rotation axis, both the intensity at the line center and the line width increase with rotational velocity. Along the same line of sight, the line becomes single peaked at rotational velocities close to half the line width in the static case. Notably, we find that rotation does not induce any spatial anisotropy in the integrated line flux, the escape fraction or the average number of scatterings. This is because Lyman scattering through a rotating solid-body proceeds identically to the static case. The only difference is the Doppler shift from the different regions in the sphere that move with respect to the observer. This allows us to derive an analytic approximation for the viewing-angle dependence of the emerging spectrum, as a function of rotational velocity.

  6. Modeling impacts of carbon sequestration on net greenhouse gas emissions from agricultural soils in China

    NASA Astrophysics Data System (ADS)

    Qiu, Jianjun; Li, Changsheng; Wang, Ligang; Tang, Huajun; Li, Hu; van Ranst, Eric

    2009-03-01

    Soil organic carbon (SOC) contents in many farmlands have been depleted because of the long-term history of intensive cultivation in China. Chinese farmers are encouraged to adopt alternative management practices on their farms to sequester SOC. On the basis of the availability of carbon (C) resources in the rural areas in China, the most promising practices are (1) incorporating more crop residue in the soils and (2) resuming traditional manure fertilizer. By implementing the alternative practices, increase in SOC content has been observed in some fields. This paper investigates how the C sequestration strategies could affect nitrous oxide (N2O) and methane (CH4) emissions from the agricultural soils in six selected sites across China. A process-based model, denitrification-decomposition or DNDC, which has been widely validated against data sets of SOC dynamics and N2O and CH4 fluxes observed in China, was adopted in the study to quantify the greenhouse gas impacts of enhanced crop residue incorporation and manure amendment under the diverse climate, soil, and crop rotation conditions across the six agroecosystems. Model results indicated that (1) when the alternative management practices were employed C sequestration rates increased, however, N2O or CH4 emissions were also increased for these practices; and (2) reducing the application rates of synthetic fertilizer in conjunction with the alternative practices could decrease N2O emissions while at the same time maintaining existing crop yields and C sequestration rates. The modeling approach could help with development of spatially differentiated best management practices at large regional scales.

  7. Impact of the choice of emission metric on greenhouse gas abatement and costs

    NASA Astrophysics Data System (ADS)

    van den Berg, Maarten; Hof, Andries F.; van Vliet, Jasper; van Vuuren, Detlef P.

    2015-02-01

    This paper analyses the effect of different emission metrics and metric values on timing and costs of greenhouse gas mitigation in least-cost emission pathways aimed at a forcing level of 3.5 W m-2 in 2100. Such an assessment is currently relevant in view of UNFCCC’s decision to replace the values currently used. An emission metric determines the relative weights of non-CO2 greenhouse gases in obtaining CO2-equivalent emissions. For the first commitment period of the Kyoto Protocol, the UNFCCC has used 100 year global warming potential (GWP) values as reported in IPCC’s Second Assessment Report. For the second commitment period, the UNFCCC has decided to use 100 year GWP values from IPCC’s Fourth Assessment Report. We find that such a change has only a minor impact on (the optimal timing of) global emission reductions and costs. However, using 20 year or 500 year GWPs to value non-CO2 greenhouse gases does result in a significant change in both costs and emission reductions in our model. CO2 reductions are favored over non-CO2 gases when the time horizon of the GWPs is increased. Application of GWPs with time horizons longer than 100 year can increase abatement costs substantially, by about 20% for 500 year GWPs. Surprisingly, we find that implementation of a metric based on a time-dependent global temperature potential does not necessary lead to lower abatement costs. The crucial factor here is how fast non-CO2 emissions can be reduced; if this is limited, the delay in reducing methane emissions cannot be (fully) compensated for later in the century, which increases total abatement costs.

  8. Alaska outer continental shelf beaufort sea planning area oil and gas lease sale 144. Final environmental impact statement. Volume 1

    SciTech Connect

    1996-05-01

    The Final Environmental Impact Statement (EIS) covers the proposed Beaufort Sea OCS Oil and Gas Lease Sale 144. This document includes the purpose and background of the proposed action, the alternatives, the descriptions of the affected environment, and the potential environmental effects of the proposed action and the alternatives. Proposed mitigating, measures and their potential effects are analyzed, in addition to potential cumulative effects resulting from the proposed activities.

  9. Energy Market and Economic Impacts Proposal to Reduce Greenhouse Gas Intensity with a Cap and Trade System

    EIA Publications

    2007-01-01

    This report was prepared by the Energy Information Administration (EIA), in response to a September 27, 2006, request from Senators Bingaman, Landrieu, Murkowski, Specter, Salazar, and Lugar. The Senators requested that EIA assess the impacts of a proposal that would regulate emissions of greenhouse gases (GHGs) through an allowance cap-and-trade system. The program would set the cap to achieve a reduction in emissions relative to economic output, or greenhouse gas intensity.

  10. Hurricane Andrew's impact on natural gas and oil facilities on the outer continental shelf (interim report as of November 1993)

    SciTech Connect

    Daniels, G.R.

    1994-01-01

    The interim report reviews Hurricane Andrew's impact on Federal Outer Continental Shelf (OCS) natural gas and oil drilling and production facilities. The report provides background on Hurricane Andrew's progression, discusses how OCS operators responded to the storm, summarizes the types of damage to offshore facilies caused by Hurricane Andrew, and discusses Minerals Management Service's continuing damage assessment and repair efforts. The summaries of damage estimates are presented in tables in Appendix 1. A glossary of report terminology is provided in Appendix 2.

  11. Gas

    MedlinePLUS

    ... premature birth Stanford University Prematurity Research Center Featured articles Accomplishments and lessons learned since the establishment of ... The impact of premature birth on society Featured articles How long should you wait before getting pregnant ...

  12. The development of laboratory correlations showing the impact of multiphase flow, fluid, and proppant selection upon gas well productivity

    SciTech Connect

    Penny, G.S.; Jin, L.

    1995-12-31

    This paper describes the development and use of laboratory data to show the impact of multiphase, non-Darcy flow upon gas production from hydraulic fractures. In the work, the impact of proppant type and fracturing fluid damage upon non-Darcy flow and effective conductivity vs. closure, temperature and gas/water/oil ratios is shown for sands, resin-coated sands and ceramics with various fracturing fluids. Laboratory derived correlations are then used to predict gas productivity and economics under various conditions of multiphase non-Darcy flow and the predictions are compared to field examples. The results of the testing show that multiphase non-Darcy flow dramatically increases the difference between the effective conductivities of various proppants at high closures. The laboratory data and field observations show that when this is taken into account, a premium proppant can show twice the production rate of commonly used sand products at high closures in gas wells producing as little as 10 barrels of water or condensate per MMCF.

  13. Gas

    MedlinePLUS

    ... of gases that contain sulfur. Gas in the digestive tract comes from two sources: air that you swallow and the breakdown of undigested food by bacteria in the large intestine. Certain foods may ... National Institute of Diabetes and Digestive and Kidney Diseases

  14. The impact of lithologic heterogeneity and focused fluid flow upon gas hydrate distribution in marine sediments

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sayantan; Bhatnagar, Gaurav; Dugan, Brandon; Dickens, Gerald R.; Chapman, Walter G.; Hirasaki, George J.

    2014-09-01

    Gas hydrate and free gas accumulation in heterogeneous marine sediment is simulated using a two-dimensional (2-D) numerical model that accounts for mass transfer over geological timescales. The model extends a previously documented one-dimensional (1-D) model such that lateral variations in permeability (k) become important. Various simulations quantitatively demonstrate how focused fluid flow through high-permeability zones affects local hydrate accumulation and saturation. Simulations that approximate a vertical fracture network isolated in a lower permeability shale (kfracture >> kshale) show that focused fluid flow through the gas hydrate stability zone (GHSZ) produces higher saturations of gas hydrate (25-70%) and free gas (30-60%) within the fracture network compared to surrounding shale. Simulations with a dipping, high-permeability sand layer also result in elevated saturations of gas hydrate (60%) and free gas (40%) within the sand because of focused fluid flow through the GHSZ. Increased fluid flux, a deep methane source, or both together increase the effect of flow focusing upon hydrate and free gas distribution and enhance hydrate and free gas concentrations along the high-permeability zones. Permeability anisotropy, with a vertical to horizontal permeability ratio on the order of 10-2, enhances transport of methane-charged fluid to high-permeability conduits. As a result, gas hydrate concentrations are enhanced within these high-permeability zones. The dip angle of these high-permeability structures affects hydrate distribution because the vertical component of fluid flux dominates focusing effects. Hydrate and free gas saturations can be characterized by a local Peclet number (localized, vertical, focused, and advective flux relative to diffusion) relative to the methane solubility gradient, somewhat analogous to such characterization in 1-D systems. Even in lithologically complex systems, local hydrate and free gas saturations might be characterized by basic parameters (local flux and diffusivity).

  15. Regional air quality impacts of increased natural gas production and use in Texas.

    PubMed

    Pacsi, Adam P; Alhajeri, Nawaf S; Zavala-Araiza, Daniel; Webster, Mort D; Allen, David T

    2013-04-01

    Natural gas use in electricity generation in Texas was estimated, for gas prices ranging from $1.89 to $7.74 per MMBTU, using an optimal power flow model. Hourly estimates of electricity generation, for individual electricity generation units, from the model were used to estimate spatially resolved hourly emissions from electricity generation. Emissions from natural gas production activities in the Barnett Shale region were also estimated, with emissions scaled up or down to match demand in electricity generation as natural gas prices changed. As natural gas use increased, emissions decreased from electricity generation and increased from natural gas production. Overall, NOx and SO2 emissions decreased, while VOC emissions increased as natural gas use increased. To assess the effects of these changes in emissions on ozone and particulate matter concentrations, spatially and temporally resolved emissions were used in a month-long photochemical modeling episode. Over the month-long photochemical modeling episode, decreases in natural gas prices typical of those experienced from 2006 to 2012 led to net regional decreases in ozone (0.2-0.7 ppb) and fine particulate matter (PM) (0.1-0.7 μg/m(3)). Changes in PM were predominantly due to changes in regional PM sulfate formation. Changes in regional PM and ozone formation are primarily due to decreases in emissions from electricity generation. Increases in emissions from increased natural gas production were offset by decreasing emissions from electricity generation for all the scenarios considered. PMID:23441728

  16. Toxic legacy: the environmental impact of the manufactured gas industry in the United States.

    PubMed

    Tarr, Joel A

    2014-01-01

    The manufactured gas industry provided cities in the United States with energy for light and power during much of the period from approximately 1850 to 1950. This article explores the history of the effects of this industry on air, land, and water environments; it also examines attempts by the courts and municipal and state governments to regulate gas-waste pollution and the industry's response. The article concludes by exploring the heritage of badly contaminated sites that the manufactured gas industry left to the nation after it was replaced by natural gas after World War II. PMID:24988796

  17. The potential impact of renewable energy deployment on natural gas prices in New England

    SciTech Connect

    Wiser, Ryan; Bolinger, Mark

    2004-09-20

    Concerns about the price and supply of natural gas have deepened in recent years both nationally and in New England. Renewable energy (RE) technologies can directly hedge natural gas price risk by reducing the need to purchase variable-price natural gas-fired electricity generation, and replacing that generation with fixed-price renewable electricity supply. In addition to its direct contribution to price stability, an increasing number of studies show that renewable energy deployment can also put downward pressure on natural gas prices by reducing demand for gas among gas-fired generators. These gas price reductions are, in turn, expected to reduce electricity prices and--more importantly--directly reduce consumer natural gas bills. Many recent studies have found that this effect may be significant, substantially benefiting consumers. These studies are reviewed in the attached paper, published in the proceedings of a recent national energy conference. An important consideration is that--strictly speaking--this price reduction represents a consumer benefit that comes at the expense of producers; it therefore represents a wealth transfer, not a net gain in social welfare. That said, current concerns about the price and supply of natural gas suggest that policymakers may want to pursue actions that reduce the strain of high prices on consumer energy bills.

  18. Socioeconomic impacts of natural gas curtailments: a study of the textile industry in the southeastern United States. Final report

    SciTech Connect

    Jennings, D.M.

    1980-01-01

    A study was undertaken to identify the effects of fuel curtailments in the textile industry in North and South Carolina. Regional economic and social structures were affected with natural gas curtailments in 1976 and 1977. This document presents results of the effects of production shutdown resulting from the curtailments. Chapter II presents background information on the pipelines that service the region. Chapters III and IV describe the affected communities and the observed increase in government expenditures to counteract the impacts. Chapter V contains a complete list of textile plants in the study area that had to either work under abbreviated schedules or close entirely during the winter of 1976-1977. Attention was given to economic impacts at the industrial level that may have been attributable to the curtailment. Chapter VI covers these topics. In some instances, textile mills have relocated their plant facilities because they could not be guaranteed continuous fuel service at their original site. These data are the main concern of Chapter VII. Chapter VIII concentrates on social impacts; many facilities which provide services essential to human needs were subjected to gas curtailments so that the critical energy supplies could be diverted to industry. Chapter VIII also discusses an interesting geographic separation between social and economic impacts.

  19. Shale gas, wind and water: assessing the potential cumulative impacts of energy development on ecosystem services within the Marcellus play.

    PubMed

    Evans, Jeffrey S; Kiesecker, Joseph M

    2014-01-01

    Global demand for energy has increased by more than 50 percent in the last half-century, and a similar increase is projected by 2030. This demand will increasingly be met with alternative and unconventional energy sources. Development of these resources causes disturbances that strongly impact terrestrial and freshwater ecosystems. The Marcellus Shale gas play covers more than 160,934 km(2) in an area that provides drinking water for over 22 million people in several of the largest metropolitan areas in the United States (e.g. New York City, Washington DC, Philadelphia & Pittsburgh). Here we created probability surfaces representing development potential of wind and shale gas for portions of six states in the Central Appalachians. We used these predictions and published projections to model future energy build-out scenarios to quantify future potential impacts on surface drinking water. Our analysis predicts up to 106,004 new wells and 10,798 new wind turbines resulting up to 535,023 ha of impervious surface (3% of the study area) and upwards of 447,134 ha of impacted forest (2% of the study area). In light of this new energy future, mitigating the impacts of energy development will be one of the major challenges in the coming decades. PMID:24586599

  20. Shale Gas, Wind and Water: Assessing the Potential Cumulative Impacts of Energy Development on Ecosystem Services within the Marcellus Play

    PubMed Central

    Evans, Jeffrey S.; Kiesecker, Joseph M.

    2014-01-01

    Global demand for energy has increased by more than 50 percent in the last half-century, and a similar increase is projected by 2030. This demand will increasingly be met with alternative and unconventional energy sources. Development of these resources causes disturbances that strongly impact terrestrial and freshwater ecosystems. The Marcellus Shale gas play covers more than 160,934 km2 in an area that provides drinking water for over 22 million people in several of the largest metropolitan areas in the United States (e.g. New York City, Washington DC, Philadelphia & Pittsburgh). Here we created probability surfaces representing development potential of wind and shale gas for portions of six states in the Central Appalachians. We used these predictions and published projections to model future energy build-out scenarios to quantify future potential impacts on surface drinking water. Our analysis predicts up to 106,004 new wells and 10,798 new wind turbines resulting up to 535,023 ha of impervious surface (3% of the study area) and upwards of 447,134 ha of impacted forest (2% of the study area). In light of this new energy future, mitigating the impacts of energy development will be one of the major challenges in the coming decades. PMID:24586599

  1. Impact of Contaminants Present in Coal-Biomass Derived Synthesis Gas on Water-gas Shift and Fischer-Tropsch Synthesis Catalysts

    SciTech Connect

    Alptekin, Gokhan

    2013-02-15

    Co-gasification of biomass and coal in large-scale, Integrated Gasification Combined Cycle (IGCC) plants increases the efficiency and reduces the environmental impact of making synthesis gas ("syngas") that can be used in Coal-Biomass-to-Liquids (CBTL) processes for producing transportation fuels. However, the water-gas shift (WGS) and Fischer-Tropsch synthesis (FTS) catalysts used in these processes may be poisoned by multiple contaminants found in coal-biomass derived syngas; sulfur species, trace toxic metals, halides, nitrogen species, the vapors of alkali metals and their salts (e.g., KCl and NaCl), ammonia, and phosphorous. Thus, it is essential to develop a fundamental understanding of poisoning/inhibition mechanisms before investing in the development of any costly mitigation technologies. We therefore investigated the impact of potential contaminants (H2S, NH3, HCN, AsH3, PH3, HCl, NaCl, KCl, AS3, NH4NO3, NH4OH, KNO3, HBr, HF, and HNO3) on the performance and lifetime of commercially available and generic (prepared in-house) WGS and FT catalysts.

  2. Localized Starbursts in Dwarf Galaxies Produced by the Impact of Low-metallicity Cosmic Gas Clouds

    NASA Astrophysics Data System (ADS)

    Sánchez Almeida, J.; Elmegreen, B. G.; Muñoz-Tuñón, C.; Elmegreen, D. M.; Pérez-Montero, E.; Amorín, R.; Filho, M. E.; Ascasibar, Y.; Papaderos, P.; Vílchez, J. M.

    2015-09-01

    Models of galaxy formation predict that gas accretion from the cosmic web is a primary driver of star formation over cosmic history. Except in very dense environments where galaxy mergers are also important, model galaxies feed from cold streams of gas from the web that penetrate their dark matter halos. Although these predictions are unambiguous, the observational support has been indirect so far. Here, we report spectroscopic evidence for this process in extremely metal-poor galaxies (XMPs) of the local universe, taking the form of localized starbursts associated with gas having low metallicity. Detailed abundance analyses based on Gran Telescopio Canarias optical spectra of 10 XMPs show that the galaxy hosts have metallicities around 60% solar, on average, while the large star-forming regions that dominate their integrated light have low metallicities of some 6% solar. Because gas mixes azimuthally in a rotation timescale (a few hundred Myr), the observed metallicity inhomogeneities are only possible if the metal-poor gas fell onto the disk recently. We analyze several possibilities for the origin of the metal-poor gas, favoring the metal-poor gas infall predicted by numerical models. If this interpretation is correct, XMPs trace the cosmic web gas in their surroundings, making them probes to examine its properties.

  3. Impact of oil and gas infrastructure development in La Manga Canyon, NM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    La Manga Canyon is a small watershed (~20km2) in the San Juan Basin that has historically been developed for natural gas and recently for coal bed methane. Since gas production began in the 1940s, an extensive network of dirt roads have transected the watershed, providing access to well sites. There...

  4. The Impact of Molecular Gas on Mass Models of Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Frank, B. S.; de Blok, W. J. G.; Walter, F.; Leroy, A.; Carignan, C.

    2016-04-01

    We present CO velocity fields and rotation curves for a sample of nearby galaxies, based on data from HERACLES. We combine our data with THINGS, SINGS, and KINGFISH results to provide a comprehensive sample of mass models of disk galaxies inclusive of molecular gas. We compare the kinematics of the molecular (CO from HERACLES) and atomic (H i from THINGS) gas distributions to determine the extent to which CO may be used to probe the dynamics in the inner part of galaxies. In general, we find good agreement between the CO and H i kinematics, with small differences in the inner part of some galaxies. We add the contribution of the molecular gas to the mass models in our galaxies by using two different conversion factors αCO to convert CO luminosity to molecular gas mass surface density—the constant Milky Way value and the radially varying profiles determined in recent work based on THINGS, HERACLES, and KINGFISH data. We study the relative effect that the addition of the molecular gas has on the halo rotation curves for Navarro–Frenk–White and the observationally motivated pseudo-isothermal halos. The contribution of the molecular gas varies for galaxies in our sample—for those galaxies where there is a substantial molecular gas content, using different values of αCO can result in significant differences to the relative contribution of the molecular gas and hence the shape of the dark matter halo rotation curves in the central regions of galaxies.

  5. Cropping System Impacts on Greenhouse Gas Emissions in the Cool, Humid Northeastern U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimating global greenhouse gas (GHG) emissions from agriculture requires regional measurements of different production systems. A long-term potato cropping systems experiment in Maine was designed to contribute to the USDA-ARS national project entitled Greenhouse Gas Reduction through Agricultural...

  6. Impact of Higher Natural Gas Prices on Local Distribution Companies and Residential Customers

    EIA Publications

    2007-01-01

    This report examines some of the problems faced by natural gas consumers as a result of increasing heating bills in recent years and problems associated with larger amounts of uncollectible revenue and lower throughput for the local distribution companies (LDCs) supplying the natural gas.

  7. Technological Change and Its Labor Impact in Five Energy Industries. Coal Mining/Oil and Gas Extraction/Petroleum Refining/Petroleum Pipeline Transportation/Electric and Gas Utilities.

    ERIC Educational Resources Information Center

    Bureau of Labor Statistics (DOL), Washington, DC.

    This bulletin appraises major technological changes emerging in five American industries (coal mining, oil and gas extraction, petroleum refining, petroleum pipeline transportation, and electric and gas utilities) and discusses the impact of these changes on productivity and occupations over the next five to ten years. Its separate reports on each…

  8. Technological Change and Its Labor Impact in Five Energy Industries. Coal Mining/Oil and Gas Extraction/Petroleum Refining/Petroleum Pipeline Transportation/Electric and Gas Utilities.

    ERIC Educational Resources Information Center

    Bureau of Labor Statistics (DOL), Washington, DC.

    This bulletin appraises major technological changes emerging in five American industries (coal mining, oil and gas extraction, petroleum refining, petroleum pipeline transportation, and electric and gas utilities) and discusses the impact of these changes on productivity and occupations over the next five to ten years. Its separate reports on each

  9. Impact of Shale Gas Development on Water Resource in Fuling, China

    NASA Astrophysics Data System (ADS)

    Yang, Hong; Huang, Xianjin; Yang, Qinyuan; Tu, Jianjun

    2015-04-01

    As a low-carbon energy, shale gas rapidly developed in U.S. in last years due to the innovation of the technique of hydraulic fracture, or fracking. Shale gas boom produces more gas with low price and reduced the reliance on fuel import. To follow the American shale gas success, China made an ambitious plan of shale gas extraction, 6.5 billion m3 by 2015. To extract shale gas, huge amount water is needed to inject into each gas well. This will intensify the competition of water use between industry, agricultural and domestic sectors. It may finally exacerbate the water scarcity in China. After the extraction, some water was returned to the ground. Without adequate treatment, the flowback water can introduce heavy metal, acids, pesticides, and other toxic material into water and land. This may inevitably worsen the water and land contamination. This study analysed the potential water consumption and wastewater generation in shale gas development in Fuling, Southwest China. The survey found the average water consumption is 30,000 cubic meter for one well, higher than shale well in U.S. Some 2%-20% water flowed back to the ground. The water quality monitoring showed the Total Suspended Solid (TSS) and Chemical Oxygen Demand (COD) were the main factors above those specified by China's water regulation. Shale gas is a lower-carbon energy, but it is important to recognize the water consuming and environmental pollution during the fracking. Strict monitoring and good coordination during the shale gas exploitation is urgently needed for the balance of economic development, energy demand and environmental protection.

  10. Natural Gas Variability In California: Environmental Impacts And Device Performance Combustion Modeling of Pollutant Emissions From a Residential Cooking Range

    SciTech Connect

    Tonse, S. R.; Singer, B. C.

    2011-07-01

    As part of a larger study of liquefied natural gas impacts on device performance and pollutant emissions for existing equipment in California, this report describes a cmoputer modeling study of a partially premixed flame issueing from a single cooktop burner port. The model consisted of a reactive computational fluid dynamics three-dimensional spatial grid and a 71-species chemical mechanism with propane combustion capability. Simulations were conducted with a simplified fuel mixture containing methane, ethane, and propane in proportions that yield properties similar to fuels distributed throughout much of California now and in recent years (baseline fuel), as well as with two variations of simulated liquefied natural gas blends. A variety of simulations were conducted with baseline fuel to explore the effect of several key parameters on pollutant formation and other flame characteristics. Simulations started with fuel and air issuing through the burner port, igniting, and continuing until the flame was steady with time. Conditions at this point were analyzed to understand fuel, secondary air and reaction product flows, regions of pollutant formation, and exhaust concentrations of carbon monoxide, nitric oxide and formaldehyde. A sensitivity study was conducted, varying the inflow parameters of this baseline gs about real-world operating conditions. Flame properties responded as expected from reactive flow theory. In the simulation, carbon monoxide levels were influenced more by the mixture's inflow velocity than by the gas-to-air ratio in the mixture issuing from the inflow port. Additional simulations were executed at two inflow conditions - high heat release and medium heat release - to examine the impact of replacing the baseline gas with two mixtures representative of liquefied natural gas. Flame properties and pollutant generation rates were very similar among the three fuel mixtures.

  11. A Study of the Impact of Variations on Aerodynamic Flow in Gas Turbine Engines via Monte-Carlo Simulations

    NASA Technical Reports Server (NTRS)

    Ngo, Khiem Viet; Tumer, Irem Y.

    2003-01-01

    The unsteady compressible inviscid flow is characterized by the conservations of mass, momentum, and energy; or simply the Euler equations. In this paper, a study of the subsonic one-dimensional Euler equations with local preconditioning is presented with a modal analysis approach. Specifically, this study investigates the behavior of airflow in a gas turbine engine using the specified conditions at the inflow and outflow boundaries of the compressor, combustion chamber, and turbine, under the impact of variations in pressure, velocity, temperature, and density at low Mach numbers. Two main questions that motivate this research are: 1) Is there any aerodynamic problem with the existing gas turbine engines that could impact aircraft performance? 2) If yes, what aspect of a gas turbine engine could be improved via design to alleviate that impact and to optimize aircraft performance. This paper presents an initial attempt to the flow behavior in terms (perturbation) using simulation outputs from a customer-deck model obtained from Pratt&Whitney, (i.e., pressure, temperature, velocity, density) about their mean states at the inflow and outflow boundaries of the compressor, combustion chamber, and turbine. Flow behavior is analyzed for the high pressure compressor and combustion chamber employing the conditions on their left and right boundaries. In the same fashion, similar analyses are carried out for the high and low-pressure turbines. In each case, the eigenfrequencies that are obtained for different boundary conditions are examined closely based on their probabilistic distributions, a result of a Monte Carlo 10,000-sample simulation. Furthermore, the characteristic waves and eave response are analyzed and contrasted among different cases, with and without preconditioners. The results reveal the existence of flow instabilities due to the combined effect of variations and excessive pressures; which are clearly the case in the combustion chamber and high-pressure turbine. Finally a discussion is presented on potential impacts of the instabilities and what can be improved via design to alleviate them for a better aircraft performance.

  12. Application of nonparametric regression and statistical testing to identify the impact of oil and natural gas development on local air quality

    SciTech Connect

    Pekney, Natalie J.; Cheng, Hanqi; Small, Mitchell J.

    2015-11-05

    Abstract: The objective of the current work was to develop a statistical method and associated tool to evaluate the impact of oil and natural gas exploration and production activities on local air quality.

  13. Selective determination of 2,4-xylenol by gas chromatography/supersonic jet/resonance-enhanced multiphoton ionization/time-of-flight mass spectrometry.

    PubMed

    Tsukatani, Hiroko; Okudaira, Hiroki; Shitamichi, Osamu; Uchimura, Tomohiro; Imasaka, Totaro

    2010-12-01

    Gas chromatography/supersonic jet/resonance-enhanced multiphoton ionization/time-of-flight mass spectrometry (GC/SSJ/REMPI/TOF-MS) was employed for isomer-selective determination of 2,4-xylenol in river and seawater samples. The sample containing 2,4-xylenol was measured using argon, rather than helium, as the GC carrier gas to cool the analyte molecule sufficiently. The instrumental detection limit (IDL) achieved at a flow rate of 1 mLmin(-1) was 14 pg. Although this value was comparable to the value (ca. 10 pg) obtained by gas chromatography/electron impact/quadrupole mass spectrometry (GC/EI/QMS). When the flow rate was increased to 8 mLmin(-1), interference from the 2,5-xylenol isomer was completely suppressed. The IDL was degraded to 83 or 160 pg at a flow rate of 5 or 8 mLmin(-1), respectively. The recovery of 2,4-xylenol from the river and the seawater samples was 85 and 93%, respectively. The time for analysis was only 10 min per one sample in GC/SSJ/REMPI/TOF-MS. These results suggest that GC/SSJ/REMPI/TOF-MS is useful for the selective measurement of 2,4-xylenol, which has been designated a Class I chemical substance in the Pollutant Release and Transfer Register (PRTR). PMID:21056717

  14. Simultaneous water and gas injection pilot at the Kuparek River Field, surface line impact

    SciTech Connect

    Stoisits, R.F.; Krist, G.J.; Rugen, J.A.

    1995-12-31

    Immiscible writer alternating gas (IWAG) injection has effectively managed produced gas at the Kuparuk River Field: increasing field oil rate and recovery. Although IWAG economics are very favorable, this pilot study was undertaken to ascertain whether separate water and gas injection lines to the drill sites and on-pad distribution systems can be eliminated by simultaneously injecting water and gas in waterflood lines. A significant problem in simultaneous water and gas injection is the phase separation which occurs at branches in the injection pipe network. The higher density phase, because of its greater momentum, will tend to flow in the straight or least deviated pipe branch, while the lower density phase will tend to flow into the most deviated branch of pipe. Studies conducted at ARCO`s Exploration and Production Technology Research Center in Plano, Texas; indicated that static mixers positioned at the pipe branches could achieve equal distribution of the phases to both runs of the pipe branch. In the pilot study gas was injected into all 8 inches waterflood line which supplied two drill sites. A static mixer was placed at the function for the two drill sites. Static mixers were also placed in the 4 inches injection manifold of one of the drill sites, the other drill site had no mixers in the injection manifold. Gas was distributed to both drill sites. At the drill site with static mixers in the injection manifold. gas was distributed to the wells on the injection manifold; while at the drill site without static mixers, phase separation occurred and only one well on the injection manifold received gas.

  15. Contributions of gas flaring to a global air pollution hotspot: Spatial and temporal variations, impacts and alleviation

    NASA Astrophysics Data System (ADS)

    Anejionu, Obinna C. D.; Whyatt, J. Duncan; Blackburn, G. Alan; Price, Catheryn S.

    2015-10-01

    Studies of environmental impacts of gas flaring in the Niger Delta are hindered by limited access to official flaring emissions records and a paucity of reliable ambient monitoring data. This study uses a combination of geospatial technologies and dispersion modelling techniques to evaluate air pollution impacts of gas flaring on human health and natural ecosystems in the region. Results indicate that gas flaring is a major contributor to air pollution across the region, with concentrations exceeding WHO limits in some locations over certain time periods. Due to the predominant south-westerly wind, concentrations are higher in some states with little flaring activity than in others with significant flaring activity. Twenty million people inhabit areas of high flare-associated air pollution, which include all of the main ecological zones of the region, indicating that flaring poses a substantial threat to human health and the environment. Model scenarios demonstrated that substantial reductions in pollution could be achieved by stopping flaring at a small number of the most active sites and by improving overall flaring efficiency.

  16. Possibility of Production of Amino Acids by Impact Reaction Using a Light-Gas Gun as a Simulation of Asteroid Impacts

    NASA Astrophysics Data System (ADS)

    Okochi, Kazuki; Mieno, Tetsu; Kondo, Kazuhiko; Hasegawa, Sunao; Kurosawa, Kosuke

    2015-06-01

    In order to investigate impact production of carbonaceous products by asteroids on Titan and other satellites and planets, simulation experiments were carried out using a 2-stage light gas gun. A small polycarbonate or metal bullet with about 6.5 km/s was injected into a pressurized target chamber filled with 1 atm of nitrogen gas, to collide with a ice + iron target or an iron target or a ice + hexane + iron target. After the impact, black soot including fine particles was deposited on the chamber wall. The soot was carefully collected and analyzed by High Performance Liquid Chromatography (HPLC), Fourier Transform Infrared Spectroscopy (FT-IR), and Laser Desorption Time-of-Flight Mass Spectrometry (LD-ToF-MS). As a result of the HPLC analysis, about 0.04-8 pmol of glycine, and a lesser amount of alanine were found in the samples when the ice + hexane + iron target was used. In case of the ice + iron target and the iron target, less amino acids were produced. The identification of the amino acids was also supported by FTIR and LD-ToF-MS analysis.

  17. Possibility of production of amino acids by impact reaction using a light-gas gun as a simulation of asteroid impacts.

    PubMed

    Okochi, Kazuki; Mieno, Tetsu; Kondo, Kazuhiko; Hasegawa, Sunao; Kurosawa, Kosuke

    2015-06-01

    In order to investigate impact production of carbonaceous products by asteroids on Titan and other satellites and planets, simulation experiments were carried out using a 2-stage light gas gun. A small polycarbonate or metal bullet with about 6.5 km/s was injected into a pressurized target chamber filled with 1 atm of nitrogen gas, to collide with a ice + iron target or an iron target or a ice + hexane + iron target. After the impact, black soot including fine particles was deposited on the chamber wall. The soot was carefully collected and analyzed by High Performance Liquid Chromatography (HPLC), Fourier Transform Infrared Spectroscopy (FT-IR), and Laser Desorption Time-of-Flight Mass Spectrometry (LD-ToF-MS). As a result of the HPLC analysis, about 0.04-8 pmol of glycine, and a lesser amount of alanine were found in the samples when the ice + hexane + iron target was used. In case of the ice + iron target and the iron target, less amino acids were produced. The identification of the amino acids was also supported by FTIR and LD-ToF-MS analysis. PMID:25796389

  18. First Environmental Impact Statement for an Oil and Gas Project to use the Comprehensive Air Quality Model with Extensions (CAMx) for the Far-Field Assessment including Ozone Impacts

    NASA Astrophysics Data System (ADS)

    Parker, L. K.; Shah, T.; Johnson, J.; Grant, J.; Bar-Ilan, A.; Kemball-Cook, S. R.; Zapert, J.; Morris, R.

    2014-12-01

    The CAMx photochemical grid model was used to estimate potential air quality and air quality related values (acid deposition and visibility) impacts caused by the drilling and production of 8950 proposed natural gas wells in southwest Wyoming. This is the first time CAMx has been used to assess the far-field air quality impacts, including ozone, in an environmental impact statement for an oil and gas project. CAMx source apportionment capabilities estimated project-specific contributions to total ambient air concentrations for ozone, NO2, SO2, PM2.5, PM10, as well as acid deposition and potential visibility impacts from the proposed gas wells. The project emissions were based on a very detailed inventory generated with operator input. Ozone impacts caused by the wells were lower than expected in the vicinity of the project, and made no significant contribution to high ozone concentrations (modeled and monitored) northwest of the project area.

  19. Results of Two-Stage Light-Gas Gun Development Efforts and Hypervelocity Impact Tests of Advanced Thermal Protection Materials

    NASA Technical Reports Server (NTRS)

    Cornelison, C. J.; Watts, Eric T.

    1998-01-01

    Gun development efforts to increase the launching capabilities of the NASA Ames 0.5-inch two-stage light-gas gun have been investigated. A gun performance simulation code was used to guide initial parametric variations and hardware modifications, in order to increase the projectile impact velocity capability to 8 km/s, while maintaining acceptable levels of gun barrel erosion and gun component stresses. Concurrent with this facility development effort, a hypervelocity impact testing series in support of the X-33/RLV program was performed in collaboration with Rockwell International. Specifically, advanced thermal protection system materials were impacted with aluminum spheres to simulate impacts with on-orbit space debris. Materials tested included AETB-8, AETB-12, AETB-20, and SIRCA-25 tiles, tailorable advanced blanket insulation (TABI), and high temperature AFRSI (HTA). The ballistic limit for several Thermal Protection System (TPS) configurations was investigated to determine particle sizes which cause threshold TPS/structure penetration. Crater depth in tiles was measured as a function of impact particle size. The relationship between coating type and crater morphology was also explored. Data obtained during this test series was used to perform a preliminary analysis of the risks to a typical orbital vehicle from the meteoroid and space debris environment.

  20. CO2 utilization and storage in shale gas reservoirs: Experimental results and economic impacts

    DOE PAGESBeta

    Schaef, Herbert T.; Davidson, Casie L.; Owen, Antionette Toni; Miller, Quin R. S.; Loring, John S.; Thompson, Christopher J.; Bacon, Diana H.; Glezakou, Vassiliki Alexandra; McGrail, B. Peter

    2014-12-31

    Natural gas is considered a cleaner and lower-emission fuel than coal, and its high abundance from advanced drilling techniques has positioned natural gas as a major alternative energy source for the U.S. However, each ton of CO2 emitted from any type of fossil fuel combustion will continue to increase global atmospheric concentrations. One unique approach to reducing anthropogenic CO2 emissions involves coupling CO2 based enhanced gas recovery (EGR) operations in depleted shale gas reservoirs with long-term CO2 storage operations. In this paper, we report unique findings about the interactions between important shale minerals and sorbing gases (CH4 and CO2) andmore » associated economic consequences. Where enhanced condensation of CO2 followed by desorption on clay surface is observed under supercritical conditions, a linear sorption profile emerges for CH4. Volumetric changes to montmorillonites occur during exposure to CO2. Theory-based simulations identify interactions with interlayer cations as energetically favorable for CO2 intercalation. Thus, experimental evidence suggests CH4 does not occupy the interlayer and has only the propensity for surface adsorption. Mixed CH4:CO2 gas systems, where CH4 concentrations prevail, indicate preferential CO2 sorption as determined by in situ infrared spectroscopy and X-ray diffraction techniques. Collectively, these laboratory studies combined with a cost-based economic analysis provide a basis for identifying favorable CO2-EOR opportunities in previously fractured shale gas reservoirs approaching final stages of primary gas production. Moreover, utilization of site-specific laboratory measurements in reservoir simulators provides insight into optimum injection strategies for maximizing CH4/CO2 exchange rates to obtain peak natural gas production.« less

  1. Impact of Fuel Interchangeability on dynamic Instabilities in Gas Turbine Engines

    SciTech Connect

    Ferguson, D.H.; Straub, D.L.; Richards, G.A.; Robey, E.H.

    2007-03-01

    Modern, low NOx emitting gas turbines typically utilize lean pre-mixed (LPM) combustion as a means of achieving target emissions goals. As stable combustion in LPM systems is somewhat intolerant to changes in operating conditions, precise engine tuning on a prescribed range of fuel properties is commonly performed to avoid dynamic instabilities. This has raised concerns regarding the use of imported liquefied natural gas (LNG) and natural gas liquids (NGL’s) to offset a reduction in the domestic natural gas supply, which when introduced into the pipeline could alter the fuel BTU content and subsequently exacerbate problems such as combustion instabilities. The intent of this study is to investigate the sensitivity of dynamically unstable test rigs to changes in fuel composition and heat content. Fuel Wobbe number was controlled by blending methane and natural gas with various amounts of ethane, propane and nitrogen. Changes in combustion instabilities were observed, in both atmospheric and pressurized test rigs, for fuels containing high concentrations of propane (> 62% by vol). However, pressure oscillations measured while operating on typical “LNG like” fuels did not appear to deviate significantly from natural gas and methane flame responses. Mechanisms thought to produce changes in the dynamic response are discussed.

  2. The Impact of Water Regulation on the Availability of Shale Gas Resources for Production

    NASA Astrophysics Data System (ADS)

    Victor, D. G.

    2011-12-01

    Visions for a large increase in North American production of natural gas from shale are based heavily on the sharp rise in the estimated available resource. Those estimates are prepared by looking at the underlying geology as well as the cost and availability of technologies for extracting gas. We add to that equation the potential current and future regulation of water injection (subsurface) and runoff (surface). Using the political science theory of "veto points" we show that US water legislation is organized in ways that allow for large numbers of political forces to block (or make costly) access to gas resources. By our estimate, 26% of the shale gas resource will be unavailable-a fraction that could rise if there are strong contagion effects as jurisdictions that have traditionally had industry-friendly regulatory systems apply much stricter rules. This work has potentially large implications for visions of the new natural gas revolution and the price of North American (and potentially world) natural gas.

  3. Greenhouse gas emission impacts of electric vehicles under varying driving cycles in various counties and US cities

    SciTech Connect

    Wang, M.Q.; Marr, W.W.

    1994-02-10

    Electric vehicles (EVs) can reduce greenhouse gas emissions, relative to emissions from gasoline-fueled vehicles. However, those studies have not considered all aspects that determine greenhouse gas emissions from both gasoline vehicles (GVs) and EVs. Aspects often overlooked include variations in vehicle trip characteristics, inclusion of all greenhouse gases, and vehicle total fuel cycle. In this paper, we estimate greenhouse gas emission reductions for EVs, including these important aspects. We select four US cities (Boston, Chicago, Los Angeles, and Washington, D.C.) and six countries (Australia, France, Japan, Norway, the United Kingdom, and the United States) and analyze greenhouse emission impacts of EVs in each city or country. We also select six driving cycles developed around the world (i.e., the US federal urban driving cycle, the Economic Community of Europe cycle 15, the Japanese 10-mode cycle, the Los Angeles 92 cycle, the New York City cycle, and the Sydney cycle). Note that we have not analyzed EVs in high-speed driving (e.g., highway driving), where the results would be less favorable to EVs; here, EVs are regarded as urban vehicles only. We choose one specific driving cycle for a given city or country and estimate the energy consumption of four-passenger compact electric and gasoline cars in the given city or country. Finally, we estimate total fuel cycle greenhouse gas emissions of both GVs and EVs by accounting for emissions from primary energy recovery, transportation, and processing; energy product transportation; and powerplant and vehicle operations.

  4. Impact of AGN and stellar feedback on the gas of a simulated z~2 star-forming galaxy

    NASA Astrophysics Data System (ADS)

    Roos, Orianne; Bournaud, Frdric; Juneau, Stephanie; Gabor, Jared

    2015-08-01

    With high-resolution simulations of star-forming disk galaxies at high redshift, we study the effects of combined AGN and stellar feedback models on the gas of the host-galaxy. AGN feedback is modeled using a standard thermal recipe of feedback (gas is heated and pushed away) plus a post-processing method to compute AGN ionization. We first consider AGN feedback only and show that, even though the AGN generates powerful outflows, the effects of AGN feedback on star formation is relatively weak on time-scales up to a few 100s of Myrs, even when long-range radiative feedback is accounted for. Furthermore, as the combination of stellar feedback models generates outflows that are more powerful than the sum of the models taken separately, we check whether combined AGN and stellar feedback also couple non-linearly. We then include several stellar feedback sources on top of AGN feedback, such as young stars creating HII regions through radiative pressure and supernovae releasing thermal and kinetic energy in the ISM. We follow their impact on the gas of high-resolution simulations and study the coupling between the different sources of outflows (AGN, young stars, supernovae) , which could produce very fast outflows, with important outflow rates. How do these feedback-driven winds affect the host? What is the amount of expelled gas? What is its density and temperature and what is the consequence for in place and future star formation? Can such outflows change the distribution of existing stars?

  5. The impact of the Sarbanes Oxley Act on auditing fees: An empirical study of the oil and gas industry

    NASA Astrophysics Data System (ADS)

    Ezelle, Ralph Wayne, Jr.

    2011-12-01

    This study examines auditing of energy firms prior and post Sarbanes Oxley Act of 2002. The research explores factors impacting the asset adjusted audit fee of oil and gas companies and specifically examines the effect of the Sarbanes Oxley Act. This research analyzes multiple year audit fees of the firms engaged in the oil and gas industry. Pooled samples were created to improve statistical power with sample sizes sufficient to test for medium and large effect size. The Sarbanes Oxley Act significantly increases a firm's asset adjusted audit fees. Additional findings are that part of the variance in audit fees was attributable to the market value of the enterprise, the number of subsidiaries, the receivables and inventory, debt ratio, non-profitability, and receipt of a going concern report.

  6. Contemporaneous mass extinctions, continental flood basalts, and `impact signals': are mantle plume-induced lithospheric gas explosions the causal link?

    NASA Astrophysics Data System (ADS)

    Phipps Morgan, J.; Reston, T. J.; Ranero, C. R.

    2004-01-01

    Contemporaneous occurrences of the geologic signals of 'large impacts', craton-associated continental flood basalts, and mass extinctions have occurred far too often during the past 400 Myr to be plausibly attributed to random coincidence. While there is only a 1 in 8 chance that even one synchronous large impact within the interval of a continental flood basalt and mass extinction event should have happened during this period, there is now geologic evidence of four such 'coincidences', implying causal links between them. The 66 Ma (K-T) evidence suggests that impacts do not trigger flood basalts, since the Deccan flood basalt had started erupting well before the Chicxulub impact event. If extraterrestrial impacts do not trigger continental flood basalt volcanism, then we are really only left with two possible resolutions to the dilemma posed by these mega-coincidences: either the reported 'impact signals' at the times of great mass extinctions are spurious or misleading, or - somehow - a terrestrial process linked to continental rifting and the eruption of cratonic flood basalts is sometimes able to generate the shocked quartz, microspherules, and other geologic traces commonly attributed to large extraterrestrial impacts, while also triggering a mass extinction event. Here we explore a promising mechanistic link: a large explosive carbon-rich gas release event from cratonic lithosphere, triggered by mantle plume incubation beneath cratonic lithosphere, and typically associated with the onset phase of continental rifting. Sudden CO 2/CO and SO 2 release into the atmosphere would provide the primary killing mechanism of the induced extinction event. Such explosive deep-lithospheric blasts could create shock waves, cavitation, and mass jet formation within the venting region that could both create and transport a sufficiently large mass of shocked crust and mantle into globally dispersive super-stratospheric trajectories. We suggest these be called 'Verneshot' events.

  7. Bering Sea summary report: Outer Continental Shelf oil and gas activities in the Bering Sea and their onshore impacts

    SciTech Connect

    Deis, J.; Pierson, R.; Kurz, F.

    1983-09-01

    Two federal offshore oil-and-gas lease sales have been held in the Bering Sea Subregion. Lease Sale 57, Norton Basin, was held on March 15, 1983. Lease Sale 70, St. George Basin, was held on April 12, 1983. The sale offered 479 tracts, of which 97 received bids. The Department of the Interior has indicated that it will accept 96 of the 97 high bids; however, to date, leases have not been awarded. The Department of the Interior was enjoined from issuing leases by the US District Court of Alaska because of possible impacts from postlease preliminary seismic activities on gray and right whales. In accordance with the Court's ruling, leases cannot be issued until the completion of a supplemental environmental impact statement, which is anticipated to occur in November 1983. Six lease offerings in the Bering Sea Subregion are scheduled through 1987. Six deep stratigraphic test wells are the only wells drilled to date in the Bering Sea Subregion. To date, oil companies have not submitted exploration plans for the Norton Basin Planning Area. Exploration in Norton Basin could begin in the summer of 1984, at the earliest. Exploration plans cannot be submitted for the St. George Basin Planning Area until the leases are awarded. At this time, various onshore areas are being considered as possible support bases for offshore oil-and-gas exploration. At this stage, before exploratory drilling has occurred and in the absence of a commercial discovery, plans for transporting petroleum from the Bering Sea to markets in the United States are unclear. The current estimates of risked resources for lands leased in Lease Sale 57, Norton Basin, are 33 million barrels of oil and 110 billion cubic feet of gas. Lease Sale 70, St. George Basin, estimates of risked resources for leased lands are 27 million barrels of oil and 310 billion cubic feet of gas. 55 references, 10 figures, 3 tables.

  8. PAH sorption mechanism and partitioning behavior in lampblack-impacted soils from former oil-gas plant sites.

    PubMed

    Hong, Lei; Ghosh, Upal; Mahajan, Tania; Zare, Richard N; Luthy, Richard G

    2003-08-15

    This study assessed polycyclic aromatic hydrocarbon (PAH) association and aqueous partitioning in lampblack-impacted field soils from five sites in California that formerly housed oil-gas process operations. Lampblack is the solid residue resulting from the decomposition of crude oil at high temperatures in the gas-making operation and is coated or impregnated with oil gasification byproducts, among which PAHs are the compounds of the greatest regulatory concern. A suite of complementary measurements investigated the character of lampblack particles and PAH location and the associated effects on PAH partitioning between lampblack and water. PAH analyses on both whole samples and density-separated components demonstrated that 81-100% of PAHs in the lampblack-impacted soils was associated with lampblack particles. FTIR, 13C NMR, and SEM analyses showed that oil-gas lampblack solids comprise primarily aromatic carbon with soot-like structures. A free-phase aromatic oil may be present in some of the lampblack soils containing high PAH concentrations. Comparable long-term aqueous partitioning measurements were obtained with an air-bridge technique and with a centrifugation/alum flocculation procedure. Large solid/water partition coefficient (Kd) values were observed in samples exhibiting lower PAH and oil levels, whereas smaller Kd values were measured in lampblack samples containing high PAH levels. The former result is in agreement with an oil-soot partitioning model, and the latter is in agreement with a coal tar-water partitioning model. Lampblack containing high PAH levels appears to exhaust the sorption capacity of the soot-carbon, creating a free aromatic oil phase that exhibits partitioning behavior similar to PAHs in coal tar. This study improves mechanistic understanding of PAH sorption on aged lampblack residuals at former oil-gas sites and provides a framework for mechanistic assessment of PAH leaching potential and risk from such site materials. PMID:12953875

  9. AIR QUALITY IMPACTS OF LIQUEFIED NATURAL GAS IN THE SOUTH COAST AIR BASIN OF CALIFORNIA

    SciTech Connect

    Carerras-Sospedra, Marc; Brouwer, Jack; Dabdub, Donald; Lunden, Melissa; Singer, Brett

    2011-07-01

    The effects of liquefied natural gas (LNG) on pollutant emission inventories and air quality in the South Coast Air Basin of California were evaluated using recent LNG emission measurements by Lawrence Berkeley National Laboratory and the Southern California Gas Company (SoCalGas), and with a state-of-the-art air quality model. Pollutant emissions can be affected by LNG owing to differences in composition and physical properties, including the Wobbe index, a measure of energy delivery rate. This analysis uses LNG distribution scenarios developed by modeling Southern California gas flows, including supplies from the LNG receiving terminal in Baja California, Mexico. Based on these scenarios, the projected penetratino of LNG in the South Coast Air Basin is expected to be limited. In addition, the increased Wobbe index of delivered gas (resulting from mixtures of LNG and conventional gas supplies) is expected to cause increases smaller than 0.05 percent in overall (area-wide) emissions of nitrogen oxides (NOx). BAsed on the photochemical state of the South Coast Air Basin, any increase in NOx is expected to cause an increase in the highest local ozone concentrations, and this is reflected in model results. However, the magnitude of the increase is well below the generally accepted accuracy of the model and would not be discernible with the existing monitoring network. Modeling of hypothetical scenarios indicates that discernible changes to ambient ozone and particulate matter concentrations would occur only at LNG distribution rates that are not achievable with current or planned infrastructure and with Wobbe index vlaues that exceed current gas quality tariffs. Results of these hypothetical scenarios are presented for consideration of any proposed substantial expansion of LNG supply infrastructure in Southern California.

  10. Multiscale study of bacterial growth: Experiments and model to understand the impact of gas exchange on global growth

    NASA Astrophysics Data System (ADS)

    Lalanne-Aulet, David; Piacentini, Adalberto; Guillot, Pierre; Marchal, Philippe; Moreau, Gilles; Colin, Annie

    2015-11-01

    Using a millifluidics and macroscale setup, we study quantitatively the impact of gas exchange on bacterial growth. In millifluidic environments, the permeability of the incubator materials allows an unlimited oxygen supply by diffusion. Moreover, the efficiency of diffusion at small scales makes the supply instantaneous in comparison with the cell division time. In hermetic closed vials, the amount of available oxygen is low. The growth curve has the same trend but is quantitatively different from the millifluidic situation. The analysis of all the data allows us to write a quantitative modeling enabling us to capture the entire growth process.

  11. Screening of steroids in horse urine and plasma by using electron impact and chemical ionization gas chromatography-mass spectrometry.

    PubMed

    Singh, A K; Gordon, B; Hewetson, D; Granley, K; Ashraf, M; Mishra, U; Dombrovskis, D

    1989-10-01

    Gas chromatography with chemical ionization mass spectrometry and selected-ion monitoring provided a sensitive method for the screening and confirmation of steroids in horse urine and plasma. Chemical ionization mass spectrometry was more sensitive than the electron impact ionization mass spectrometry for most of the steroids except for testosterone, prednisone-metabolite-2 and prednisolone-metabolite-2. The chromatographic conditions used in this study provided clean separation of different natural and synthetic steroids. Approximately 75-85% of the steroids added to plasma and approximately 65-70% of the steroids added to urine were recovered by the extraction procedure used in this study. PMID:2808600

  12. [Impact of introduction of O2 on the welding arc of gas pool coupled activating TIG].

    PubMed

    Huang, Yong; Wang, Yan-Lei; Zhang, Zhi-Guo

    2014-05-01

    In the present paper, Boltzmann plot method was applied to analyze the temperature distributions of the are plasma when the gas pool coupled activating TIG welding was at different coupling degrees with the outer gas being O2. Based on this study of temperature distributions, the changing regularities of are voltage and are appearance were studied. The result shows that compared with traditional TIG welding, the introduction of O2 makes the welding arc constricted slightly, the temperature of the are center build up, and the are voltage increase. When argon being the inner gas, oxygen serving as the outer gas instead of argon makes the are constricted more obviously. When the coupling degree increases from 0 to 2, the temperature of the are center and the are voltage both increase slightly. In the gas pool coupled activating TIG welding the are is constricted not obviously, and the reason why the weld penetration is improved dramatically in the welding of stainless steel is not are constriction. PMID:25095400

  13. Regional Air Quality Impacts of Hydraulic Fracturing and Natural Gas Activity: Evidence from Ambient VOC Observations

    NASA Astrophysics Data System (ADS)

    Vinciguerra, T.; Ehrman, S.; Yao, S.; Dadzie, J.; Chittams, A.; Dickerson, R. R.

    2014-12-01

    Over the past decade, many anthropogenic pollutants have been successfully reduced, providing improved air quality. However, a new influx of emissions associated with hydraulic fracturing and natural gas operations could be counteracting some of these benefits. Using hourly measurements from Photochemical Assessment Monitoring Stations (PAMS) in the Baltimore, MD and Washington, D.C. areas, we observed that following a period of decline, daytime ethane concentrations have increased significantly since 2010. This trend appears to be linked with the rapid natural gas production in upwind, neighboring states, especially Pennsylvania and West Virginia. Furthermore, ethane concentrations failed to display this trend at a PAMS site outside of Atlanta, GA, a region without widespread natural gas operations. Year-to-year changes in VOCs were further evaluated by using Positive Matrix Factorization (PMF) to perform source apportionment on hourly observations in Essex, MD from 2005-2013. This process takes ambient measurements and attributes them to sources such as biogenic, natural gas, industrial, gasoline, and vehicle exhaust by using tracer species as identifiers. Preliminary PMF results also indicate an increasing influence of natural gas sources for this area.

  14. Impact of Chlorine Dioxide Gas Sterilization on Nosocomial Organism Viability in a Hospital Room

    PubMed Central

    Lowe, John J.; Gibbs, Shawn G.; Iwen, Peter C.; Smith, Philip W.; Hewlett, Angela L.

    2013-01-01

    To evaluate the ability of ClO2 to decontaminate pathogens known to cause healthcare-associated infections in a hospital room strains of Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis, Mycobacterium smegmatis, and Staphylococcus aureus were spot placed in duplicate pairs at 10 sites throughout a hospital room and then exposed to ClO2 gas. Organisms were collected and evaluated for reduction in colony forming units following gas exposure. Six sterilization cycles with varied gas concentrations, exposure limits, and relative humidity levels were conducted. Reductions in viable organisms achieved ranged from 7 to 10-log reductions. Two sterilization cycles failed to produce complete inactivation of organisms placed in a bathroom with the door closed. Reductions of organisms in the bathroom ranged from 6-log to 10-log reductions. Gas leakage between hospital floors did not occur; however, some minor gas leakage from the door of hospital room was measured which was subsequently sealed to prevent further leakage. Novel technologies for disinfection of hospital rooms require validation and safety testing in clinical environments. Gaseous ClO2 is effective for sterilizing environmental contamination in a hospital room. Concentrations of ClO2 up to 385 ppm were safely maintained in a hospital room with enhanced environmental controls. PMID:23792697

  15. Impact of mine wastewaters on greenhouse gas emissions from northern peatlands used for mine water treatment

    NASA Astrophysics Data System (ADS)

    Palmer, Katharina; Ronkanen, Anna-Kaisa; Klöve, Björn; Hynynen, Jenna; Maljanen, Marja

    2015-04-01

    The amount of wastewaters generated during mining operations is increasing along with the increasing number of operation mines, which poses great challenges for mine water management and purification. Mine wastewaters contain high concentrations of nitrogen compounds such as nitrate (NO3-) and ammonium (NH4+) originating from remnant explosives as well as sulfate (SO42-) originating from the oxidation of sulfidic ores. At a mine site in Finnish Lapland, two natural peatlands have been used for cost-effective passive wastewater treatment. One peatland have been used for the treatment of drainage waters (TP 1), while the other has been used for the treatment of process-based wastewaters (TP 4). In this study, the impact of mine water derived nitrogen compounds as well as SO42- on the emission of the potent greenhouse gases methane (CH4) and nitrous oxide (N2O) from those treatment peatlands was investigated. Contaminant concentrations in the input and output waters of the treatment peatlands were monitored which allowed for the calculation of contaminant-specific retention efficiencies. Treatment peatlands showed generally good retention efficiencies for metals and metalloids (e.g. nickel, arsenic, antimony, up to 98% reduction in concentration) with rather low input-concentrations (i.e., in the μg/l-range). On the other hand, retention of contaminants with high input-concentrations (i.e., in mg/l-range) such as NO3-, NH4+ and SO42- was much lower (4-41%, 30-60% and -42-30%, respectively), indicating the limited capability of the treatment peatlands to cope with such high input concentrations. NO3- and NH4+ concentrations were determined in surface and pore water from TP 4 in July 2013 as well as in surface water from TP 1 and TP 4 in October 2013. Up to 720 μM NO3- and up to 600 μM NH4+ were detected in surface water of TP 4 in July 2013. NO3- and NH4+ concentrations in surface waters were highest near the mine wastewater distribution ditch and decreased with increasing distances from the ditch. NO3- concentrations were lower in pore water than in surface water, and the peak in NO3- concentration shifted further away from the distribution ditch with increasing depth. On the contrary, NH4+ concentrations were generally higher in pore water than in surface water, and peak concentrations increased with increasing depth. Highest NH4+ concentrations were detected in 30 to 60 cm depth near the outlet at the south end of TP 4. Fluxes of the greenhouse gases CH4 and N2O from 4 sampling points (2 from TP 4, 1 from TP 1, 1 from reference area) were measured on 7 different occasions 2013 and 2014. CH4 emissions were in the same range as measured in other northern pristine peatlands in the reference area, which is not influenced by mine wastewaters. Treatment peatlands showed only very minor CH4 emissions or even CH4 uptake. On the other hand, treatment peatlands showed high N2O emissions, which were in the same range as N2O emissions observed from northern peat soils used for agriculture. Highest emissions were generally observed near the wastewater distribution ditch of TP 4. N2O emissions from the reference area were negligible or even negative. NO3-, NH4+ and SO42- concentrations were determined from surface waters from each sampling point and sampling occasion. N2O emissions were positively correlated with NO3- concentrations, indicating denitrification-derived N2O production in treatment peatlands. On the other hand, CH4 emissions were negatively correlated with SO42- and NO3- concentrations, indicating that the presence of alternative electron acceptors in large amounts suppresses CH4 production in treatment peatlands. In conclusion, the study revealed that (i) treatment peatlands receive high loads of NO3-, NH4+ and SO42- which are not well retained in the peatlands, (ii) mine wastewaters positively and negatively affect N2O and CH4 emissions, respectively, (iii) N2O emissions are positively correlated with NO3- concentrations, and (iv) CH4 emissions are negatively correlated with NO3- and SO42- concentrations. This study thus illustrates the pronounced impacts of mine wastewaters on processes involved in greenhouse gas turnover in peatlands ecosystems.

  16. Impact of gas flow rate on breakdown of filamentary dielectric barrier discharges

    NASA Astrophysics Data System (ADS)

    Höft, H.; Becker, M. M.; Kettlitz, M.

    2016-03-01

    The influence of gas flow rate on breakdown properties and stability of pulsed dielectric barrier discharges (DBDs) in a single filament arrangement using a gas mixture of 0.1 vol. % O2 in N2 at atmospheric pressure was investigated by means of electrical and optical diagnostics, accompanied by fluid dynamics and electrostatics simulations. A higher flow rate perpendicular to the electrode symmetry axis resulted in an increased breakdown voltage and DBD current maximum, a higher discharge inception jitter, and a larger emission diameter of the discharge channel. In addition, a shift of the filament position for low gas flow rates with respect to the electrode symmetry axis was observed. These effects can be explained by the change of the residence time of charge carriers in the discharge region—i.e., the volume pre-ionization—for changed flow conditions due to the convective transport of particles out of the center of the gap.

  17. Urban leakage of liquefied petroleum gas and its impact on Mexico City air quality

    SciTech Connect

    Blake, D.R.; Rowland, F.S.

    1995-08-18

    Alkane hydrocarbons (propane, isobutane, and n-butane) from liquefied petroleum gas (LPG) are present in major quantities throughout Mexico City air because of leakage of the unburned gas from numerous urban sources. These hydrocarbons, together with olefinic minor LPG components, furnish substantial amounts of hydroxyl radical reactivity, a major precursor to formation of the ozone component of urban smog. The combined processes of unburned leakage and incomplete combustion of LPG play significant role in causing the excessive ozone characteristic of Mexico City. Reductions in ozone levels should be possible through changes in LPG composition and lowered rates of leakage. 23 refs., 3 tabs.

  18. Hazard Ranking Methodology for Assessing Health Impacts of Unconventional Natural Gas Development and Production: The Maryland Case Study.

    PubMed

    Boyle, Meleah D; Payne-Sturges, Devon C; Sangaramoorthy, Thurka; Wilson, Sacoby; Nachman, Keeve E; Babik, Kelsey; Jenkins, Christian C; Trowell, Joshua; Milton, Donald K; Sapkota, Amir

    2016-01-01

    The recent growth of unconventional natural gas development and production (UNGDP) has outpaced research on the potential health impacts associated with the process. The Maryland Marcellus Shale Public Health Study was conducted to inform the Maryland Marcellus Shale Safe Drilling Initiative Advisory Commission, State legislators and the Governor about potential public health impacts associated with UNGDP so they could make an informed decision that considers the health and well-being of Marylanders. In this paper, we describe an impact assessment and hazard ranking methodology we used to assess the potential public health impacts for eight hazards associated with the UNGDP process. The hazard ranking included seven metrics: 1) presence of vulnerable populations (e.g. children under the age of 5, individuals over the age of 65, surface owners), 2) duration of exposure, 3) frequency of exposure, 4) likelihood of health effects, 5) magnitude/severity of health effects, 6) geographic extent, and 7) effectiveness of setbacks. Overall public health concern was determined by a color-coded ranking system (low, moderately high, and high) that was generated based on the overall sum of the scores for each hazard. We provide three illustrative examples of applying our methodology for air quality and health care infrastructure which were ranked as high concern and for water quality which was ranked moderately high concern. The hazard ranking was a valuable tool that allowed us to systematically evaluate each of the hazards and provide recommendations to minimize the hazards. PMID:26726918

  19. Hazard Ranking Methodology for Assessing Health Impacts of Unconventional Natural Gas Development and Production: The Maryland Case Study

    PubMed Central

    Sangaramoorthy, Thurka; Wilson, Sacoby; Nachman, Keeve E.; Babik, Kelsey; Jenkins, Christian C.; Trowell, Joshua; Milton, Donald K.; Sapkota, Amir

    2016-01-01

    The recent growth of unconventional natural gas development and production (UNGDP) has outpaced research on the potential health impacts associated with the process. The Maryland Marcellus Shale Public Health Study was conducted to inform the Maryland Marcellus Shale Safe Drilling Initiative Advisory Commission, State legislators and the Governor about potential public health impacts associated with UNGDP so they could make an informed decision that considers the health and well-being of Marylanders. In this paper, we describe an impact assessment and hazard ranking methodology we used to assess the potential public health impacts for eight hazards associated with the UNGDP process. The hazard ranking included seven metrics: 1) presence of vulnerable populations (e.g. children under the age of 5, individuals over the age of 65, surface owners), 2) duration of exposure, 3) frequency of exposure, 4) likelihood of health effects, 5) magnitude/severity of health effects, 6) geographic extent, and 7) effectiveness of setbacks. Overall public health concern was determined by a color-coded ranking system (low, moderately high, and high) that was generated based on the overall sum of the scores for each hazard. We provide three illustrative examples of applying our methodology for air quality and health care infrastructure which were ranked as high concern and for water quality which was ranked moderately high concern. The hazard ranking was a valuable tool that allowed us to systematically evaluate each of the hazards and provide recommendations to minimize the hazards. PMID:26726918

  20. Climate Change Impacts and Greenhouse Gas Mitigation Effects on U.S. Hydropower Generation

    EPA Science Inventory

    Climate change will have potentially significant effects on hydropower generation due to changes in the magnitude and seasonality of river runoff and increases in reservoir evaporation. These physical impacts will in turn have economic consequences through both producer revenues ...

  1. Social Impacts of Oil and Gas Developments on a Small Rural Community.

    ERIC Educational Resources Information Center

    Copp, James H.

    To examine the effects of the 1978-81 oil and gas boom on social and economic relations and institutions in Caldwell, Texas, researchers gathered data about the community using census information, historical accounts, official records, publications, observations, interviews, and surveys of 133 residents, 91 businesses, and 40 oil field service

  2. Impact of Dissociation and Sensible Heat Release on Pulse Detonation and Gas Turbine Engine Performance

    NASA Technical Reports Server (NTRS)

    Povinelli, Louis A.

    2001-01-01

    A thermodynamic cycle analysis of the effect of sensible heat release on the relative performance of pulse detonation and gas turbine engines is presented. Dissociation losses in the PDE (Pulse Detonation Engine) are found to cause a substantial decrease in engine performance parameters.

  3. Impact of different plants on the gas profile of a landfill cover

    SciTech Connect

    Reichenauer, Thomas G.; Watzinger, Andrea; Riesing, Johann; Gerzabek, Martin H.

    2011-05-15

    Research highlights: > Plants influence gas profile and methane oxidation in landfill covers. > Plants regulate water content and increase the availability of oxygen for methane oxidation. > Plant species with deep roots like alfalfa showed more stimulation of methane oxidation than plants with shallow root systems like grasses. - Abstract: Methane is an important greenhouse gas emitted from landfill sites and old waste dumps. Biological methane oxidation in landfill covers can help to reduce methane emissions. To determine the influence of different plant covers on this oxidation in a compost layer, we conducted a lysimeter study. We compared the effect of four different plant covers (grass, alfalfa + grass, miscanthus and black poplar) and of bare soil on the concentration of methane, carbon dioxide and oxygen in lysimeters filled with compost. Plants were essential for a sustainable reduction in methane concentrations, whereas in bare soil, methane oxidation declined already after 6 weeks. Enhanced microbial activity - expected in lysimeters with plants that were exposed to landfill gas - was supported by the increased temperature of the gas in the substrate and the higher methane oxidation potential. At the end of the first experimental year and from mid-April of the second experimental year, the methane concentration was most strongly reduced in the lysimeters containing alfalfa + grass, followed by poplar, miscanthus and grass. The observed differences probably reflect the different root morphology of the investigated plants, which influences oxygen transport to deeper compost layers and regulates the water content.

  4. Air Quality Impacts of Oil and Gas Operations in the Northern Colorado Front Range

    NASA Astrophysics Data System (ADS)

    Helmig, D.; Thompson, C. R.; Jacques, H.; Smith, K. R.; Terrell, R. M.

    2014-12-01

    Exceedences of the US EPA National Ambient Air Quality Standard (NAAQS) for surface ozone have been reported from monitoring sites in the Northern Colorado Front Range (NCFR) for more than fifteen years during summer. Comparison of ozone records from the NCFR clearly show that ozone primarily results from regional photochemical daytime production. Recent trend analyses do not show an improvement of surface ozone despite efforts by the State of Colorado to curb ozone precursor emissions. Our review of atmospheric volatile organic compound (VOC) measurements from historic and recent monitoring shows significant spatial increases of atmospheric VOC towards the oil and gas development area in Weld County, NW of the Denver-Boulder metropolitan region. Secondly, analyses of VOC trends and VOC signatures show an overall increase of oil and gas associated VOC relative to other VOC sources. These analyses suggest that oil and gas emissions are playing and increasing role in ozone production in the NCFR and that reductions of oil and gas emissions would be beneficial for lowering surface ozone and attainment of the ozone NAAQS.

  5. Identifying emerging smart grid impacts to upstream and midstream natural gas operations.

    SciTech Connect

    McIntyre, Annie

    2010-09-01

    The Smart Grid has come to describe a next-generation electrical power system that is typified by the increased use of communications and information technology in the generation, delivery and consumption of electrical energy. Much of the present Smart Grid analysis focuses on utility and consumer interaction. i.e. smart appliances, home automation systems, rate structures, consumer demand response, etc. An identified need is to assess the upstream and midstream operations of natural gas as a result of the smart grid. The nature of Smart Grid, including the demand response and role of information, may require changes in upstream and midstream natural gas operations to ensure availability and efficiency. Utility reliance on natural gas will continue and likely increase, given the backup requirements for intermittent renewable energy sources. Efficient generation and delivery of electricity on Smart Grid could affect how natural gas is utilized. Things that we already know about Smart Grid are: (1) The role of information and data integrity is increasingly important. (2) Smart Grid includes a fully distributed system with two-way communication. (3) Smart Grid, a complex network, may change the way energy is supplied, stored, and in demand. (4) Smart Grid has evolved through consumer driven decisions. (5) Smart Grid and the US critical infrastructure will include many intermittent renewables.

  6. Cropping System Management Impacts on Greenhouse Gas Emissions in the Cool, Humid Northeastern U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimating global greenhouse gas (GHG) emissions requires regional measurements be made within different production systems. A long-term potato cropping system experiment established in 2004 in Presque Isle, ME, on a sandy loam soil was designed to contribute to three of the following scenarios rel...

  7. Impact study on the use of biomass-derived fuels in gas turbines for power generation

    SciTech Connect

    Moses, C.A.; Bernstein, H.

    1994-01-01

    This report evaluates the properties of fuels derived from biomass, both gaseous and liquid, against the fuel requirements of gas turbine systems for gernating electrical power. The report attempts to be quantitative rather than merely qualitative to establish the significant variations in the properties of biomass fuels from those of conventional fuels. Three general categories are covered: performance, durability, and storage and handling.

  8. Impact of biochar field aging on laboratory greenhouse gas production potentials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent observations of decreased greenhouse gas (GHG) production from biochar amended soils have been used to further substantiate the environmental benefit of biochar production and soil incorporation strategies. However, the mechanisms behind the “biochar effect” have not been fully elucidated. In...

  9. The Effect of Greenhouse Gas Mitigation on Drought Impacts in the U.S.

    EPA Science Inventory

    In this paper, we present a methodology for analyzing the economic benefits in the U.S. of changes in drought frequency and severity due to global greenhouse gas (GHG) mitigation. We construct reduced-form models of the effect of drought on agriculture and reservoir recreation i...

  10. Social Impacts of Oil and Gas Developments on a Small Rural Community.

    ERIC Educational Resources Information Center

    Copp, James H.

    To examine the effects of the 1978-81 oil and gas boom on social and economic relations and institutions in Caldwell, Texas, researchers gathered data about the community using census information, historical accounts, official records, publications, observations, interviews, and surveys of 133 residents, 91 businesses, and 40 oil field service…

  11. Impact of Time to First Rainfall Event on Greenhouse Gas Emissions Following Manure Applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Use of inorganic fertilizers and manures are known to result in the release of greenhouse gases to the atmosphere, and rainfall events can also increase greenhouse gas emissions from soils. However, little is known about the temporal relationship between fertilizer application and rainfall on greenh...

  12. When galaxy clusters collide: the impact of merger shocks on cluster gas and galaxy evolution

    NASA Astrophysics Data System (ADS)

    Stroe, A.

    2015-09-01

    Galaxy clusters mainly grow through mergers with other clusters and groups. Major mergers give rise to cluster-wide traveling shocks, which can be detected at radio wavelengths as relics: elongated, diffuse synchrotron emitting areas located at the periphery of merging clusters. The 'Sausage' cluster hosts an extraordinary Mpc-wide relic, which enables us to study to study particle acceleration and the effects of shocks on cluster galaxies. We derive shock properties and the magnetic field structure for the relic. Our results indicate that particles are shock-accelerated, but turbulent re-acceleration or unusually efficient transport of particles in the downstream area are important effects. We demonstrate the feasibility of high-frequency observations of radio relics, by presenting a 16 GHz detection of the 'Sausage' relic. Halpha mapping of the cluster provides the first direct test as to whether the shock drives or prohibits star formation. We find numerous galaxies in! close proximity to the radio relic which are extremely massive, metal-rich, star-forming with evidence for gas mass loss though outflows. We speculate that the complex interaction between the merger, the shock wave and gas is a fundamental driver in the evolution of cluster galaxies from gas rich spirals to gas-poor ellipticals.

  13. Determining the Origins and Impact of Hot Gas in the Milky Way

    NASA Astrophysics Data System (ADS)

    Miller, Matthew J.; Bregman, Joel N.; Hodges-Kluck, Edmund J.

    2016-01-01

    The Milky Way's circumgalactic medium contains million degree gas that is volume-filling on ≥10 kpc scales based on X-ray emission from the ROSAT All-Sky Survey, detections of OVII Kα (λ=21.602 Å) absorption lines at z~0 in AGN spectra, ubiquitous detections of OVII-OVIII emission lines in ~1,000 blank-sky spectra, and the discovery of the ~10 kpc outflow from the Galactic center known as the Fermi bubbles. Analyses on the line strengths in individual or small samples of sight lines (< 30) imply plasma densities between 10-5-10-2 cm-3, but the dominant hot gas structure is argued to be either a disk morphology (~108 M⊙ of material) or a spherical morphology (1010-1011 M⊙ of material). This is a crucial distinction since these morphologies arise from significantly different galaxy evolution processes, and the Fermi bubbles are recently discovered objects that are interacting with the ambient CGM. In this dissertation, I constrain the global hot gas density structure by comparing the largest samples of OVII equivalent width measurements and OVII-OVIII line intensities with model line strengths from parametric density models. I find that a spherical profile with n ∝ r-3/2 extending to the Milky Way's virial radius results in model line strenghts that are most consistent with how the observed line strengths vary across the sky. These results imply a hot gas mass between 2-5 x 1010 M⊙ within 250 kpc (≤ 50% of the Galactic missing baryons), a hot gas metallicity of Z ≥ .3 Z⊙, and that most of the hot gas formed as shock-heated material during the Milky Way's formation. For the Fermi bubbles, the line intensities and ratios suggest they contain hotter gas than the surrounding medium (> 2 x 106 K) and densities between 10-4-10-3 cm-3. This implies the bubbles are over-pressurized and expanding into the surrounding halo, potentially heating and displacing the ambient CGM.

  14. The extra-large light-gas gun of the Fraunhofer EMI: Applications for impact cratering research

    NASA Astrophysics Data System (ADS)

    Lexow, B.; Wickert, M.; Thoma, K.; Sch?Fer, F.; Poelchau, M. H.; Kenkmann, T.

    2013-01-01

    The extra-large light-gas gun (XLLGG) at the Fraunhofer Ernst-Mach-Institut (EMI, Efringen-Kirchen, Germany) is a two-stage light-gas gun that can accelerate projectile masses of up to 100 g up to velocities of 6 km s-1. The accelerator's set-up allows various combinations of pump and launch tubes for applications in different fields of hypervelocity impact research. In the framework of the MEMIN (Multidisciplinary Experimental and Modeling Impact Research Network) program, the XLLGG is used for mesoscale cratering experiments with projectiles made of steel and of iron meteorites, and targets consisting of sandstone and other rocks. The craters produced with this equipment reach a diameter of up to 40 cm, a size unique in laboratory cratering research. With the implementation of neural networks, the acceleration process is being optimized, currently yielding peak velocities of 7.8 km s-1 for a 100 g projectile. Here, we summarize technical aspects of the XLLGG.

  15. Evaluating options for balancing the water-electricity nexus in California: Part 2--greenhouse gas and renewable energy utilization impacts.

    PubMed

    Tarroja, Brian; AghaKouchak, Amir; Sobhani, Reza; Feldman, David; Jiang, Sunny; Samuelsen, Scott

    2014-11-01

    A study was conducted to compare the technical potential and effectiveness of different water supply options for securing water availability in a large-scale, interconnected water supply system under historical and climate-change augmented inflow and demand conditions. Part 2 of the study focused on determining the greenhouse gas and renewable energy utilization impacts of different pathways to stabilize major surface reservoir levels. Using a detailed electric grid model and taking into account impacts on the operation of the water supply infrastructure, the greenhouse gas emissions and effect on overall grid renewable penetration level was calculated for each water supply option portfolio that successfully secured water availability from Part 1. The effects on the energy signature of water supply infrastructure were found to be just as important as that of the fundamental processes for each option. Under historical (baseline) conditions, many option portfolios were capable of securing surface reservoir levels with a net neutral or negative effect on emissions and a benefit for renewable energy utilization. Under climate change augmented conditions, however, careful selection of the water supply option portfolio was required to prevent imposing major emissions increases for the system. Overall, this analysis provided quantitative insight into the tradeoffs associated with choosing different pathways for securing California's water supply. PMID:25087186

  16. Impact of alternative fuels on emissions characteristics of a gas turbine engine - part 1: gaseous and particulate matter emissions.

    PubMed

    Lobo, Prem; Rye, Lucas; Williams, Paul I; Christie, Simon; Uryga-Bugajska, Ilona; Wilson, Christopher W; Hagen, Donald E; Whitefield, Philip D; Blakey, Simon; Coe, Hugh; Raper, David; Pourkashanian, Mohamed

    2012-10-01

    Growing concern over emissions from increased airport operations has resulted in a need to assess the impact of aviation related activities on local air quality in and around airports, and to develop strategies to mitigate these effects. One such strategy being investigated is the use of alternative fuels in aircraft engines and auxiliary power units (APUs) as a means to diversify fuel supplies and reduce emissions. This paper summarizes the results of a study to characterize the emissions of an APU, a small gas turbine engine, burning conventional Jet A-1, a fully synthetic jet fuel, and other alternative fuels with varying compositions. Gas phase emissions were measured at the engine exit plane while PM emissions were recorded at the exit plane as well as 10 m downstream of the engine. Five percent reduction in NO(x) emissions and 5-10% reduction in CO emissions were observed for the alternative fuels. Significant reductions in PM emissions at the engine exit plane were achieved with the alternative fuels. However, as the exhaust plume expanded and cooled, organic species were found to condense on the PM. This increase in organic PM elevated the PM mass but had little impact on PM number. PMID:22913288

  17. the Impact of Biogenic Gas on DNAPLs' Migration in Coarse Sand

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Yang, J.; Ye, S.; Wu, J.

    2011-12-01

    Dense Non-Aqueous Phase Liquids (DNAPLs) are major concerns in many common groundwater contaminants. DNAPLs have low solubilities and significant vapor pressures, which allow them to partition into the gas phase of the unsaturated zone. Bioremediation is a promising alternative to traditional technologies at treating DNAPLs because of its noninvasive and cost-effective. A two-dimensional sandbox system was set up for investigating flow and transport of TCE in saturated and unsaturated porous media. Image analysis of multiphase flow in the sandbox by a charge-coupled device (CCD) camera was found to be effective in monitoring the migration of DNAPL and gas bubbles. To simulate the bubbles generated by microbes, the unsaturated medium was developed by injecting air into the cell through sampling needle at the fixed location. In both saturated and unsaturated condition, TCE move downward because of its weight and density and form a pool at the bottom of the cell. In addition, the local dense "lens" of the porous media can make TCE change the path of infiltration. The movement of TCE in the unsaturated cell is slightly slower than its movement on the saturated condition. The gas bubbles hinder the movement of TCE. Some residual TCE are founded in the unsaturated phase of the cell. In the multiphase system, the saturations of DNAPL, gas and water can be estimated by using the light intensity and correlate models. The results show that it is consistent to the observations except that there is relative large error in the beginning of the DNAPL infiltration. However, as long as the experiments carry on, the relative error can decrease to 1%. What's more, the volume amount of infiltration of DNAPL and gas bubbles can also be estimated by light intensity through the cell. It is feasible to use the light transmission method to characterize the movement and spatial distribution of DNAPL in saturated and unsaturated porous media.

  18. Impacts of prescribed burning on soil greenhouse gas fluxes in a suburban native forest of south-eastern Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Wang, Y. Z.; Xu, Z. H.; Fu, L.

    2015-11-01

    Prescribed burning is a forest management practice that is widely used in Australia to reduce the risk of damaging wildfires. Prescribed burning can affect both carbon (C) and nitrogen (N) cycling in the forest and thereby influence the soil-atmosphere exchange of major greenhouse gases, i.e. carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). To quantify the impact of a prescribed burning (conducted on 27 May 2014) on greenhouse gas exchange and the potential controlling mechanisms, we carried out a series of field measurements before (August 2013) and after (August 2014 and November 2014) the fire. Gas exchange rates were determined in four replicate plots which were burned during the combustion and in another four adjacent unburned plots located in green islands, using a set of static chambers. Surface soil properties including temperature, pH, moisture, soil C and N pools were also determined either by in situ measurement or by analysing surface 10 cm soil samples. All of the chamber measurements indicated a net sink of atmospheric CH4, with mean CH4 uptake ranging from 1.15 to 1.99 mg m-2 d-1. Prescribed burning significantly enhanced CH4 uptake as indicated by the significant higher CH4 uptake rates in the burned plots measured in August 2014. In the following 3 months, the CH4 uptake rate was recovered to the pre-burning level. Mean CO2 emission from the forest soils ranged from 2721.76 to 7113.49 mg m-2 d-1. The effect of prescribed burning on CO2 emission was limited within the first 3 months, as no significant difference was observed between the burned and the adjacent unburned plots in both August and November 2014. The CO2 emissions showed more seasonal variations, rather than the effects of prescribed burning. The N2O emission in the plots was quite low, and no significant impact of prescribed burning was observed. The changes in understory plants and litter layers, surface soil temperature, C and N substrate availability and microbial activities, following the prescribed burning, were the factors that controlled the greenhouse gas exchanges. Our results suggested that the low-intensity prescribed burning would decrease soil CO2 emission and increase CH4 uptake, but this effect would be present within a relatively short period. Only slight changes in the surface soil properties during the combustion and very limited impacts of prescribed burning on the mineral soils supported the rapid recovery of the greenhouse gas exchange rates.

  19. Impact of Marcellus Shale natural gas development in southwest Pennsylvania on volatile organic compound emissions and regional air quality.

    PubMed

    Swarthout, Robert F; Russo, Rachel S; Zhou, Yong; Miller, Brandon M; Mitchell, Brittney; Horsman, Emily; Lipsky, Eric; McCabe, David C; Baum, Ellen; Sive, Barkley C

    2015-03-01

    The Marcellus Shale is the largest natural gas deposit in the U.S. and rapid development of this resource has raised concerns about regional air pollution. A field campaign was conducted in the southwestern Pennsylvania region of the Marcellus Shale to investigate the impact of unconventional natural gas (UNG) production operations on regional air quality. Whole air samples were collected throughout an 8050 km(2) grid surrounding Pittsburgh and analyzed for methane, carbon dioxide, and C1-C10 volatile organic compounds (VOCs). Elevated mixing ratios of methane and C2-C8 alkanes were observed in areas with the highest density of UNG wells. Source apportionment was used to identify characteristic emission ratios for UNG sources, and results indicated that UNG emissions were responsible for the majority of mixing ratios of C2-C8 alkanes, but accounted for a small proportion of alkene and aromatic compounds. The VOC emissions from UNG operations accounted for 17 ± 19% of the regional kinetic hydroxyl radical reactivity of nonbiogenic VOCs suggesting that natural gas emissions may affect compliance with federal ozone standards. A first approximation of methane emissions from the study area of 10.0 ± 5.2 kg s(-1) provides a baseline for determining the efficacy of regulatory emission control efforts. PMID:25594231

  20. Impact of anti-tacking agents on properties of gas-entrapped membrane and effervescent floating tablets.

    PubMed

    Kriangkrai, Worawut; Puttipipatkhachorn, Satit; Sriamornsak, Pornsak; Pongjanyakul, Thaned; Sungthongjeen, Srisagul

    2014-12-01

    Tackiness caused by the gas-entrapped membrane (Eudragit(®)RL 30D) was usually observed during storage of the effervescent floating tablets, leading to failure in floatation and sustained release. In this work, common anti-tacking agents (glyceryl monostearate (GMS) and talc) were used to solve this tackiness problem. The impact of anti-tacking agent on the properties of free films and corresponding floating tablets was investigated. GMS was more effective than talc in reducing tackiness of the film. Addition and increasing amount of anti-tacking agents lowered the film mechanical strength, but the coating films were still strong and flexible enough to resist the generated gas pressure inside the floating tablet. Wettability and water vapor permeability of the film decreased with increasing level of anti-tacking agents as a result of their hydrophobicity. No interaction between anti-tacking agents and polymer was observed as confirmed by Fourier transform infrared spectroscopy, powder X-ray diffractometry, and differential scanning calorimetry studies. Increasing amount of anti-tacking agents decreased time to float and tended to retard drug release of the floating tablets. Floating properties and drug release were also influenced by type of anti-tacking agents. The obtained floating tablets still possessed good floating properties and controlled drug release even though anti-tacking agent had some effects. The results demonstrated that the tackiness problem of the floating tablets could be solved by incorporating anti-tacking agent into the gas-entrapped membrane. PMID:24927669

  1. Oxygen transport from the atmosphere to soil gas beneath a slab-on-grade foundation overlying petroleum-impacted soil.

    PubMed

    Lundegard, Paul D; Johnson, Paul C; Dahlen, Paul

    2008-08-01

    Modeling and field study results suggest that, in the case of a building overlying an aerobically biodegradable vapor source (i.e., petroleum-impacted soil), the significance of vapor intrusion into the building depends on the source vapor concentration, the relative position of the vapor source and building, and the rate of O2 transport from the atmosphere to the soil gas beneath the building. This work quantified the latter at a house having about a 250 m2 slab-on-grade foundation footprint. It was constructed on 1.5 m of clean fill overlying a petroleum hydrocarbon-impacted soil layer undergoing methanogenesis. Soil gas O2 and CH4 profiles adjacent to and beneath the foundation were measured and then the soil gas beneath the slab was rapidly displaced with N2. The natural replenishment of O2 was monitored for 90 days using in situ O2 sensors, and the responses with time were similar, independent of location. The O2 replenishment rate was about 2500 g-O2/d immediately after the N2 flood and then it declined to 200-500 g-O2/d over 30 days. Weather events affected the O2 replenishment rate; an increase occurred during a strong wind period (> 3 m/s), and a decrease occurred during a heavy rainfall event. The spatial and temporal patterns in the O2 sensor responses and quantified O2 replenishment rates could not be accounted for by simple mechanistic hypotheses involving lateral diffusion or advection through the bulk soil, and instead the data suggest rapid replenishment immediately below the foundation followed by downward diffusion. PMID:18754472

  2. Impact of Natural Gas Appliances on Pollutant Levels in California Homes

    SciTech Connect

    Mullen, Nasim A.; Li, Jina; Singer, Brett C.

    2012-12-01

    This report presents results from the first year of a 2-year study, investigating associations of five air pollutants (CO, NO2, NOX, formaldehyde and acetaldehyde) with the presence of natural gas appliances in California homes. From November 2011 to March 2012, pollutant concentration and occupant activity data were collected in 155 homes for 6-day periods. The sample population included both single-family (68%) and multi-family (32%) dwellings, with 87% having at least one gas appliance and 77% having an unvented gas cooking appliance. The geometric mean (GM) NO2 levels measured in the kitchen, bedroom and outside of homes were similar at values of 15, 12 and 11 ppb, respectively. In contrast, the GM NOx levels measured in the kitchen and bedroom of homes were much higher than levels measured outdoors, at levels of 42 and 41 ppb, compared to 19 ppb, respectively. Roughly 10% of sampled homes had 6-day average NO2 levels that exceeded the outdoor annual average limit set by the California Ambient Air Quality Standards (CAAQS) (30 ppb). The GMs of the highest 1-h and 8-h CO level measured in homes were 2.5 and 1.1 ppm, respectively. Four homes had a 1-h or 8-h concentration that exceeded the outdoor limits set by the CAAQS. The GM formaldehyde and acetaldehyde concentrations measured in homes were 15 and 7 ppb, respectively. Roughly 95% of homes had average formaldehyde levels indoors that exceeded the Chronic Reference Exposure Level set by the California EPA (7 ppb). Concentrations of NO2 and NOx, and to a lesser extent CO were associated with use of gas appliances, particularly unvented gas cooking appliances. Based on first principles, it is expected that effective venting of cooking pollutant emissions at the source will lead to a reduction of pollutant concentrations. However, no statistical association was detected between kitchen exhaust fan use and pollutant concentrations in homes in this study where gas cooking occurred frequently. The lack of statistical

  3. The impact of drainage and re-flooding of a restored wetland on ecosystem-scale greenhouse gas effluxes

    NASA Astrophysics Data System (ADS)

    Novick, K. A.; Katul, G. G.; Ardon, M. L.; Morse, J. L.; Bernhardt, E. S.

    2008-12-01

    Prior to European settlement, wetland ecosystems comprised much of the low-lying land of the Southeastern U.S. coastal plain. In the centuries since, the majority of these wetlands were drained as the landscape was transformed for agricultural and silvicultural uses, with significant impacts on biosphere-atmosphere exchange of greenhouse gases, as well as a decrease in ecosystem services related to water quality. In recent years, management agencies have focused on wetland restoration in an attempt to return some of these ecosystem services. These restored wetlands are understudied ecosystems that have the potential for large source fluxes of greenhouse gases (i.e. CO2, CH4, N2O). In this study, we develop a system to estimate landscape level gas efflux in a restored wetland in Eastern N.C., and to assess the impact of rapid drainage and re-flooding on these fluxes. A mobile eddy covariance tower is deployed for the portion of the wetland that is drained from late August to early September, 2008. Simultaneously, vertical temperature profiles and concentration profiles of CO2, CH4, and N2O are collected at two locations -- one within the drained area and one adjacent to it. Eddy covariance fluxes are linked to the source area using recent source-weight function models, and fluxes are linked to measured gradients using similarities in eddy-diffusivities. A suite of meteorological measurements (radiation, humidity, temperature) and soil measurements (soil moisture, soil temperature, water table depth, soil pore trace gas concentrations) are also collected. The data are used to assess the impact of wetland draining and re- flooding on mass and energy fluxes.

  4. Impact of Intrafractional Bowel Gas Movement on Carbon Ion Beam Dose Distribution in Pancreatic Radiotherapy

    SciTech Connect

    Kumagai, Motoki; Hara, Ryusuke; Mori, Shinichiro Yanagi, Takeshi; Asakura, Hiroshi; Kishimoto, Riwa; Kato, Hirotoshi; Yamada, Shigeru; Kandatsu, Susumu; Kamada, Tadashi

    2009-03-15

    Purpose: To assess carbon ion beam dose variation due to bowel gas movement in pancreatic radiotherapy. Methods and Materials: Ten pancreatic cancer inpatients were subject to diagnostic contrast-enhanced dynamic helical CT examination under breath-holding conditions, which included multiple-phase dynamic CT with arterial, venous, and delayed phases. The arterial-venous phase and arterial-delayed phase intervals were 35 and 145 s, respectively. A compensating bolus was designed to cover the target obtained at the arterial phase. Carbon ion dose distribution was calculated by applying the bolus to the CT data sets at the other two phases. Results: Dose conformation to the clinical target volume was degraded by beam overshoot/undershoot due to bowel gas movement. The D95 for clinical target volume was degraded from 98.2% (range, 98.0-99.1%) of the prescribed dose to 94.7% (range, 88.0-99.0%) at 145 s. Excessive dosing to normal tissues varied among tissues and was, for example, 12.2 GyE/13.1 GyE (0 s/145 s) for the cord and 38.8 GyE/39.8 GyE (0 s/145 s) for the duodenum. The magnitude of beam overshoot/undershoot was particularly exacerbated from the anterior and left directions. Conclusions: Bowel gas movement causes dosimetric variation to the target during treatment for radiotherapy. The effect of bowel gas movement varies with beam angle, with greatest influence on the anterior-posterior and left-right beams.

  5. Evolving shale gas management: water resource risks, impacts, and lessons learned.

    PubMed

    Rahm, Brian G; Riha, Susan J

    2014-05-01

    Unconventional shale gas development promises to significantly alter energy portfolios and economies around the world. It also poses a variety of environmental risks, particularly with respect to the management of water resources. We review current scientific understanding of risks associated with the following: water withdrawals for hydraulic fracturing; wastewater treatment, discharge and disposal; methane and fluid migration in the subsurface; and spills and erosion at the surface. Some of these risks are relatively unique to shale gas development, while others are variations of risks that we already face from a variety of industries and activities. All of these risks depend largely on the pace and scale of development that occurs within a particular region. We focus on the United States, where the shale gas boom has been on-going for several years, paying particular attention to the Marcellus Shale, where a majority of peer-reviewed study has taken place. Governments, regulatory agencies, industry, and other stakeholders are challenged with responding to these risks, and we discuss policies and practices that have been adopted or considered by these various groups. Adaptive Management, a structured framework for addressing complex environmental issues, is discussed as a way to reduce polarization of important discussions on risk, and to more formally engage science in policy-making, along with other economic, social and value considerations. Data suggests that some risks can be substantially reduced through policy and best practice, but also that significant uncertainty persists regarding other risks. We suggest that monitoring and data collection related to water resource risks be established as part of planning for shale gas development before activity begins, and that resources are allocated to provide for appropriate oversight at various levels of governance. PMID:24664241

  6. On The Impact of Borescope Camera Air Purge on DWPF Melter Off-Gas Flammability

    SciTech Connect

    CHOI, ALEXANDER

    2004-07-22

    DWPF Engineering personnel requested that a new minimum backup film cooler air flow rate, which will meet the off-gas safety basis limits for both normal and seismic sludge-only operations, be calculated when the air purge to the borescope cameras is isolated from the melter. Specifically, it was requested that the latest calculations which were used to set the off-gas flammability safety bases for the sludge batch 2 and 3 feeds be revised, while maintaining all other process variables affecting off-gas flammability such as total organic carbon (TOC), feed rate, melter air purges, and vapor space temperature at their current respective maximum or minimum limits. Before attempting to calculate the new minimum backup film cooler air flow, some of the key elements of the combustion model were reviewed, and it was determined that the current minimum backup film cooler air flow of 233 lb/hr is adequate to satisfy the off-gas flammability safety bases for both normal and seismic operations i n the absence of any borescope camera air purge. It is, therefore, concluded that there is no need to revise the reference E-7 calculations. This conclusion is in essence based on the fact that the current minimum backup film cooler air flow was set to satisfy the minimum combustion air requirement under the worst-case operating scenario involving a design basis earthquake during which all the air purges not only to the borescope cameras but to the seal pot are presumed to be lost due to pipe ruptures. The minimum combustion air purge is currently set at 150 per cent of the stoichiometric air flow required to combust 3 times the normal flow of flammable gases. The DWPF control strategy has been that 100 per cent of the required minimum combustion air is to be provided by the controlled air purge through the backup film cooler alone.

  7. Impact of surface structure and feed gas composition on Bacillus subtilis endospore inactivation during direct plasma treatment.

    PubMed

    Hertwig, Christian; Steins, Veronika; Reineke, Kai; Rademacher, Antje; Klocke, Michael; Rauh, Cornelia; Schlter, Oliver

    2015-01-01

    This study investigated the inactivation efficiency of cold atmospheric pressure plasma treatment on Bacillus subtilis endospores dependent on the used feed gas composition and on the surface, the endospores were attached on. Glass petri-dishes, glass beads, and peppercorns were inoculated with the same endospore density and treated with a radio frequency plasma jet. Generated reactive species were detected using optical emission spectroscopy. A quantitative polymerase chain reaction (qPCR) based ratio detection system was established to monitor the DNA damage during the plasma treatment. Argon + 0.135% vol. oxygen + 0.2% vol. nitrogen as feed gas emitted the highest amounts of UV-C photons and considerable amount of reactive oxygen and nitrogen species. Plasma generated with argon + 0.135% vol. oxygen was characterized by the highest emission of reactive oxygen species (ROS), whereas the UV-C emission was negligible. The use of pure argon showed a negligible emission of UV photons and atomic oxygen, however, the emission of vacuum (V)UV photons was assumed. Similar maximum inactivation results were achieved for the three feed gas compositions. The surface structure had a significant impact on the inactivation efficiency of the plasma treatment. The maximum inactivation achieved was between 2.4 and 2.8 log10 on glass petri-dishes and 3.9 to 4.6 log10 on glass beads. The treatment of peppercorns resulted in an inactivation lower than 1.0 log10. qPCR results showed a significant DNA damage for all gas compositions. Pure argon showed the highest results for the DNA damage ratio values, followed by argon + 0.135% vol. oxygen + 0.2% vol. nitrogen. In case of argon + 0.135% vol. oxygen the inactivation seems to be dominated by the action of ROS. These findings indicate the significant role of VUV and UV photons in the inactivation process of B. subtilis endospores. PMID:26300855

  8. Popular epidemiology and "fracking": citizens' concerns regarding the economic, environmental, health and social impacts of unconventional natural gas drilling operations.

    TOXLINE Toxicology Bibliographic Information

    Powers M; Saberi P; Pepino R; Strupp E; Bugos E; Cannuscio CC

    2015-06-01

    Pennsylvania sits atop the Marcellus Shale, a reservoir of natural gas that was untapped until the 2004 introduction of unconventional natural gas drilling operations (UNGDO) in the state. Colloquially known as fracking, UNGDO is a controversial process that employs large volumes of water to fracture the shale and capture gas; it has become a multi-billion dollar industry in Pennsylvania. We analyzed letters to the editor of the most widely circulated local newspaper in the most heavily drilled county in Pennsylvania (Bradford County) in order to characterize residents' concerns and their involvement in popular epidemiology--the process by which citizens investigate risks associated with a perceived environmental threat. We reviewed 215 letters to the editor that referenced natural gas operations and were published by The Daily Review between January 1, 2008 and June 8, 2013. We used NVivo 10 to code and analyze letters and identify major themes. Nvivo is qualitative data analysis software (http://www.qsrinternational.com/products_nvivo.aspx that allows researchers to code and analyze "unstructured" data, including text files of any type (e.g., interview transcripts, news articles, letters, archival materials) as well as photographs and videos. Nvivo can be used to classify, sort, query, comment on, and share data across a research group. Letters demonstrated citizen engagement in beginning and intermediate stages of lay epidemiology, as well as discord and stress regarding four main issues: socio-economic impacts, perceived threats to water, population growth and implications, and changes to the rural landscape. Residents called for stronger scientific evidence and a balance of economic development and health and environmental protections. Citizens' distress regarding UNGDO appeared to be exacerbated by a dearth of information to guide economic growth and health, environmental, and social concerns. This analysis proposes locally informed questions to guide future surveillance and research.

  9. Impact of surface structure and feed gas composition on Bacillus subtilis endospore inactivation during direct plasma treatment

    PubMed Central

    Hertwig, Christian; Steins, Veronika; Reineke, Kai; Rademacher, Antje; Klocke, Michael; Rauh, Cornelia; Schlüter, Oliver

    2015-01-01

    This study investigated the inactivation efficiency of cold atmospheric pressure plasma treatment on Bacillus subtilis endospores dependent on the used feed gas composition and on the surface, the endospores were attached on. Glass petri-dishes, glass beads, and peppercorns were inoculated with the same endospore density and treated with a radio frequency plasma jet. Generated reactive species were detected using optical emission spectroscopy. A quantitative polymerase chain reaction (qPCR) based ratio detection system was established to monitor the DNA damage during the plasma treatment. Argon + 0.135% vol. oxygen + 0.2% vol. nitrogen as feed gas emitted the highest amounts of UV-C photons and considerable amount of reactive oxygen and nitrogen species. Plasma generated with argon + 0.135% vol. oxygen was characterized by the highest emission of reactive oxygen species (ROS), whereas the UV-C emission was negligible. The use of pure argon showed a negligible emission of UV photons and atomic oxygen, however, the emission of vacuum (V)UV photons was assumed. Similar maximum inactivation results were achieved for the three feed gas compositions. The surface structure had a significant impact on the inactivation efficiency of the plasma treatment. The maximum inactivation achieved was between 2.4 and 2.8 log10 on glass petri-dishes and 3.9 to 4.6 log10 on glass beads. The treatment of peppercorns resulted in an inactivation lower than 1.0 log10. qPCR results showed a significant DNA damage for all gas compositions. Pure argon showed the highest results for the DNA damage ratio values, followed by argon + 0.135% vol. oxygen + 0.2% vol. nitrogen. In case of argon + 0.135% vol. oxygen the inactivation seems to be dominated by the action of ROS. These findings indicate the significant role of VUV and UV photons in the inactivation process of B. subtilis endospores. PMID:26300855

  10. Popular epidemiology and "fracking": citizens' concerns regarding the economic, environmental, health and social impacts of unconventional natural gas drilling operations.

    PubMed

    Powers, Martha; Saberi, Poune; Pepino, Richard; Strupp, Emily; Bugos, Eva; Cannuscio, Carolyn C

    2015-06-01

    Pennsylvania sits atop the Marcellus Shale, a reservoir of natural gas that was untapped until the 2004 introduction of unconventional natural gas drilling operations (UNGDO) in the state. Colloquially known as fracking, UNGDO is a controversial process that employs large volumes of water to fracture the shale and capture gas; it has become a multi-billion dollar industry in Pennsylvania. We analyzed letters to the editor of the most widely circulated local newspaper in the most heavily drilled county in Pennsylvania (Bradford County) in order to characterize residents' concerns and their involvement in popular epidemiology--the process by which citizens investigate risks associated with a perceived environmental threat. We reviewed 215 letters to the editor that referenced natural gas operations and were published by The Daily Review between January 1, 2008 and June 8, 2013. We used NVivo 10 to code and analyze letters and identify major themes. Nvivo is qualitative data analysis software (http://www.qsrinternational.com/products_nvivo.aspx) that allows researchers to code and analyze "unstructured" data, including text files of any type (e.g., interview transcripts, news articles, letters, archival materials) as well as photographs and videos. Nvivo can be used to classify, sort, query, comment on, and share data across a research group. Letters demonstrated citizen engagement in beginning and intermediate stages of lay epidemiology, as well as discord and stress regarding four main issues: socio-economic impacts, perceived threats to water, population growth and implications, and changes to the rural landscape. Residents called for stronger scientific evidence and a balance of economic development and health and environmental protections. Citizens' distress regarding UNGDO appeared to be exacerbated by a dearth of information to guide economic growth and health, environmental, and social concerns. This analysis proposes locally informed questions to guide future surveillance and research. PMID:25392053

  11. Impacts of shale gas wastewater disposal on water quality in western Pennsylvania.

    PubMed

    Warner, Nathaniel R; Christie, Cidney A; Jackson, Robert B; Vengosh, Avner

    2013-10-15

    The safe disposal of liquid wastes associated with oil and gas production in the United States is a major challenge given their large volumes and typically high levels of contaminants. In Pennsylvania, oil and gas wastewater is sometimes treated at brine treatment facilities and discharged to local streams. This study examined the water quality and isotopic compositions of discharged effluents, surface waters, and stream sediments associated with a treatment facility site in western Pennsylvania. The elevated levels of chloride and bromide, combined with the strontium, radium, oxygen, and hydrogen isotopic compositions of the effluents reflect the composition of Marcellus Shale produced waters. The discharge of the effluent from the treatment facility increased downstream concentrations of chloride and bromide above background levels. Barium and radium were substantially (>90%) reduced in the treated effluents compared to concentrations in Marcellus Shale produced waters. Nonetheless, (226)Ra levels in stream sediments (544-8759 Bq/kg) at the point of discharge were ~200 times greater than upstream and background sediments (22-44 Bq/kg) and above radioactive waste disposal threshold regulations, posing potential environmental risks of radium bioaccumulation in localized areas of shale gas wastewater disposal. PMID:24087919

  12. Impact of Gas-liquid Two-phase Flow on Fluid Borne Noise

    NASA Astrophysics Data System (ADS)

    Taniwaki, Mitsuhiro; Shimomura, Nobuo

    In pipe lines such as those found in refrigeration cycle, a gas-liquid two-phase flow may occur because of a pressure change in the pipe. This flow causes noise. A vapor phase ratio in a fluid and the behavior of bubbles are related to the outbreak of noise. This experimental study investigated the fluid borne noise caused by gas-liquid two-phase flow passing through a contracted section in horizontal pipe. In the experiment, sound pressure was measured for two purposes: to see the influence of the air-water ratio on sound pressure and to see the change in sound pressure when a single bubble passed through a contracted section in horizontal pipe. The experiment showed that the fluid borne noise of gas-liquid two-phase flow grew louder than that of a liquid single-phase flow. As for the frequency distribution of the fluid borne noise, the sound pressure level was higher in the high frequency band. Furthermore, the fluid borne noise grew louder with increasing bubble diameter.

  13. Impact of increasing atmospheric CO2 on crop gas exchange under different tillage practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing atmospheric CO2 concentration may impact production agriculture. In the fall of 1997, a study was initiated to examine the response of different tillage systems to changing atmospheric CO2 level. The study used a split-plot design (three replications) with two tillage systems (conventiona...

  14. Manure management and temperature impacts on gas concentrations in monoslope cattle facilities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Roofed and confined cattle feeding facilities are increasingly popular in the Northern Great Plains, but little is known about the impact this housing system and associated manure management methods have on the air quality inside and outside the barn. The objective of this study was to determine ga...

  15. 76 FR 52655 - Pacific Gas and Electric Company; Notice of Availability of the Final Environmental Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-23

    ...) regulations, 18 CFR part 380 (Order No. 486, 52 FR 47897), the Office of Energy Projects has reviewed the... Environmental Impact Statement for the Kilarc-Cow Creek Hydroelectric Project In accordance with the National..., contact FERC Online Support. For further information, contact the environmental coordinator,...

  16. 75 FR 37429 - Pacific Gas and Electric Company; Notice of Availability of the Draft Environmental Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-29

    ... No. 486, 52 FR 47897), the Office of Energy Projects has reviewed the application, filed March 12... Environmental Impact Statement for the Kilarc-Cow Creek Hydroelectric Project and Announcing Intention To Hold..., contact the environmental coordinator, CarLisa Linton-Peters at (202) 502-8416, or via e-mail at...

  17. Impacts of oil and gas development on the recreation and tourism off the Florida straits

    SciTech Connect

    Bell, F.

    1991-05-01

    The study was undertaken for the purpose of addressing potential problems of OCS activities on tourism and recreation in Monroe County, Florida. The strategic objective of the study was to develop a model to simulate the effects of various OCS activities on tourism visitation, expenditures, and regional gross economic impacts.

  18. 78 FR 23554 - Sierrita Gas Pipeline LLC; Supplemental Notice of Intent To Prepare an Environmental Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-19

    ... environmental issues. By this notice, the Commission requests public comments on the scope of the issues related... Environmental Impact Statement for the Sierrita Pipeline Project and Request for Comments on Environmental Issues As previously noticed on August 1, 2012, and supplemented herein, the staff of the Federal...

  19. Climate Change Impacts and Greenhouse Gas Mitigation Effects on US Water Quality

    EPA Science Inventory

    Climate change will have potentially significant effects on freshwater quality due to increases in river and lake temperatures, changes in the magnitude and seasonality of river runoff, and more frequent and severe extreme events. These physical impacts will in turn have economic...

  20. Impact of biochar on manure carbon stabilization and greenhouse gas emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous studies indicate that biochar additions sometimes increase soil respiration and carbon dioxide emissions, which could partially offset carbon (C) credits associated with soil biochar applications. Little is known, however, about the impact of biochar on the mineralization of manure in soil ...

  1. A new impact test for the identification of a dynamic crack propagation criterion using a gas-gun device

    NASA Astrophysics Data System (ADS)

    Nistor, I.; Pantal, O.; Caperaa, S.

    2006-08-01

    The modelling of damage and fracture behaviour under high rates of loadings for metallic structures presents the more and more interests for engineering design, especially for crash phenomena. In order to perform a numerical simulation of such phenomena a crack propagation criterion must be identified using adapted laboratory tests. The objective of this paper is to present a new impact test intended for the identification of a cohesive crack criterion implemented into a home-made FEM code based on Extended Finite Element Method. Therefore, a double-notched specimen is impacted using a gas-gun device in order to obtain different crack paths depending on projectile speed. A post-impact macro-photographic observation allows to measure the crack path, the angles and the advancing length. These experimental results are used as input responses in the identification procedure for determining the crack cohesive criterion parameters. Some experimental results, for an aluminium alloy crack criterion identification, are presented to illustrate the proposed approach.

  2. Impact origin of the Avak structure, Arctic Alaska, and genesis of the Barrow gas fields

    SciTech Connect

    Kirschner, C.E. ); Grantz, A.; Mullen, M.W. )

    1992-05-01

    Geophysical and subsurface geologic data suggest that the Avak structure, which underlies the Arctic Coastal Plain 12 km southeast of Barrow, Alaska, is a hypervelocity meteorite or comet impact structure. The structure is a roughly circular area of uplifted, chaotically deformed Upper Triassic to Lower Cretaceous sedimentary rocks 8 km in diameter that is bounded by a ring of anastomosing, inwardly dipping, listric normal faults 12 km in diameter. A zone of gently outward-dipping sedimentary country rocks forms a discontinuous ring of rim anticlines within the peripheral ring of normal faults. Beyond these anticlines, the sedimentary rocks are almost flat-lying. Data concerning the age of the Avak structure are not definitive. If submarine landslide deposits in the upper part of the Aptian and Albian Torok Formation, in the subsurface 200 km to the east, were triggered by the Avak event, then the Avak meteorite struck a submerged marine shelf about 100 [plus minus] 5 Ma. However, the impact features found at Avak characterize the distal zones of meteorite impact structures. Fused rocks, plastic deformation, and shock-metamorphic minerals found in more proximal zones of impact structures are apparently missing. These observations, and the lack of Avak ejecta in cuttings and cores from the Torok Formation and Nanushuk Group in surrounding test wells, indicate that the impact event postdated these beds. In this case, the Avak meteorite struck a Late Cretaceous or Tertiary marine shelf or coastal plain between the Cenomanian (ca. 95 Ma), and deposition of the basal beds of the overlying late Pliocene and Quaternary Gubik Formation (ca. 3 Ma).

  3. Impacts of prescribed burning on soil greenhouse gas fluxes in a suburban native forest of south-eastern Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Wang, Y. Z.; Xu, Z. H.; Fu, L.

    2015-07-01

    Prescribed burning is a forest management practice that is widely used in Australia to reduce the risk of damaging wildfires. It can affect both carbon (C) and nitrogen (N) cycling in the forest and thereby influence the soil-atmosphere exchange of major greenhouse gases, i.e. carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). To quantify the impact of a prescribed burning (conducted on 27 May 2014) on greenhouse gas exchange and the potential controlling mechanisms, we carried out a series of field measurements before (August 2013) and after (August 2014 and November 2014) the fire. Gas exchange rates were determined at 4 replicate sites which were burned during the combustion and another 4 adjacent unburned sites located in green islands, using a set of static chambers. Surface soil properties including temperature, pH, moisture, soil C and N pools were also determined either by in situ measurement or by analysing surface 10 cm soil samples. All of the chamber measurements indicated a net sink of atmospheric CH4, with mean CH4 uptake ranging from 1.15 to 1.99 mg m-2 day-1. The burning significantly enhanced CH4 uptake as indicated by the significant higher CH4 uptake rates at the burned sites measured in August 2014. While within the next 3 months the CH4 uptake rate was recovered to pre-burning levels. Mean CO2 emission from forest soils ranged from 2721.76 to 7113.49 mg m-2 day-1. The effect of prescribed burning on CO2 emission was limited within the first 3 months, as no significant difference was observed between the burned and the adjacent unburned sites in both August and November 2014. The temporal dynamics of the CO2 emission presented more seasonal variations, rather than burning effects. The N2O emission at the studied sites was quite low, and no significant impact of burning was observed. The changes in understory plants and litter layers, surface soil temperature, C and N substrate availability and microbial activities, resulting from the burning, were the factors that controlled the greenhouse gas exchanges. Our results suggested that the low intensity prescribed burning would decrease soil CO2 emission and increase CH4 uptake, however, this effect would be present within a relative short period. Only slight changes in the surface soil during the combustion and very limited damages in the mineral soils supported the quick recovery of the greenhouse gas exchange rates.

  4. Evaluating 2012 Ozone Impacts of Natural Gas Development in the Haynesville Shale with an Updated Emission Inventory

    NASA Astrophysics Data System (ADS)

    Kemball-Cook, S. R.; Bar-Ilan, A.; Yarwood, G.

    2013-12-01

    The Haynesville Shale, located approximately 10,000-13,000 feet beneath Northeast Texas and Northwest Louisiana contains very large recoverable reserves of natural gas. Development of the Haynesville began in 2008, and since then, more than 3,000 wells have been drilled. The development of natural gas resources in the Haynesville is economically important, but also generates emissions of ozone precursors in a region with several ozone monitors that are close to or exceeding the 2008 National Ambient Air Quality Standard. During 2009, we developed an emission inventory of ozone precursors for projected future Haynesville Shale development from 2009 through 2020. Photochemical modeling with the 2012 emission inventory showed significant ozone impacts within Northeast Texas and Northwest Louisiana as a result of Haynesville emissions, with projected 8-hour ozone design value increases up to 5 ppb at area monitors. The original emission inventory was assembled during spring 2009, early in the development of the Haynesville when available data were limited. Since then, development in the Haynesville has continued, and additional data are now available and were used to refine the development projections and emission inventory through the year 2020. The updated 2012 emission inventory is now based on actual data rather than projections made in 2009. The number of drilling rigs operating in 2012 was lower than projected, but the well count was higher due intensive drilling activity in 2010-2011 that exceeded projections. The updated emission inventory draws on more Haynesville-specific data than the previous inventory. Energy producers currently active in the Haynesville were surveyed and provided information that included well drilling times, equipment used for well construction, production equipment present at typical Haynesville wells, and produced gas composition analyses. Producers provided information on the amount of truck traffic associated with transport of materials, equipment, and personnel to and from wells and the types and activity of non-road equipment operating at well sites. Well production data for 2009 through 2012 from Texas and Louisiana state regulatory agencies was used to update the well decline curve used to project formation-wide gas production. The updated emission inventory was used to quantify 2012 ozone impacts from the Haynesville with the CAMx photochemical grid model. The ozone contribution from truck traffic was determined. We evaluated the effect of the Haynesville on ozone design values in Northeast Texas and Northwest Louisiana as well as on regional ozone. The model projections for ozone were compared to recent trends in observed ozone.

  5. Fuel-cycle greenhouse gas emissions impacts of alternative transportation fuels and advanced vehicle technologies.

    SciTech Connect

    Wang, M. Q.

    1998-12-16

    At an international conference on global warming, held in Kyoto, Japan, in December 1997, the United States committed to reduce its greenhouse gas (GHG) emissions by 7% over its 1990 level by the year 2012. To help achieve that goal, transportation GHG emissions need to be reduced. Using Argonne's fuel-cycle model, I estimated GHG emissions reduction potentials of various near- and long-term transportation technologies. The estimated per-mile GHG emissions results show that alternative transportation fuels and advanced vehicle technologies can help significantly reduce transportation GHG emissions. Of the near-term technologies evaluated in this study, electric vehicles; hybrid electric vehicles; compression-ignition, direct-injection vehicles; and E85 flexible fuel vehicles can reduce fuel-cycle GHG emissions by more than 25%, on the fuel-cycle basis. Electric vehicles powered by electricity generated primarily from nuclear and renewable sources can reduce GHG emissions by 80%. Other alternative fuels, such as compressed natural gas and liquefied petroleum gas, offer limited, but positive, GHG emission reduction benefits. Among the long-term technologies evaluated in this study, conventional spark ignition and compression ignition engines powered by alternative fuels and gasoline- and diesel-powered advanced vehicles can reduce GHG emissions by 10% to 30%. Ethanol dedicated vehicles, electric vehicles, hybrid electric vehicles, and fuel-cell vehicles can reduce GHG emissions by over 40%. Spark ignition engines and fuel-cell vehicles powered by cellulosic ethanol and solar hydrogen (for fuel-cell vehicles only) can reduce GHG emissions by over 80%. In conclusion, both near- and long-term alternative fuels and advanced transportation technologies can play a role in reducing the United States GHG emissions.

  6. Forest Conversion: Impact on Total Greenhouse Gas Balance and Mitigation Strategies

    NASA Astrophysics Data System (ADS)

    Papen, H.; Brueggemann, N.; Gasche, R.; Butterbach-Bahl, K.

    2006-12-01

    At present, large efforts are undertaken in wide parts of Germany and Europe to create the scientific and socio-economic data basis that can be used by political decision makers and foresters for developing and implementing a future-oriented forestry allowing a sustainable use of forests under changing environmental conditions (e.g. climate change and increasing N-deposition). Different forest management strategies are available to initiate forest conversion, in particular "clear-cutting" and "selective cutting". Although these forest conversion strategies are widely used, little information is available about their individual effects on the biosphere-atmosphere greenhouse gas exchange and on the total greenhouse gas balance (CO2 + N2O + CH4) of the system. The results obtained from continuous long-term measurements (1999-2005) of N2O and CH4 fluxes from the soil of different experimental sites (untreated spruce control site, selective-cutting site, clear-cut site) at the Hglwald Forest, Bavaria, Germany show that conversion of N-affected forest plantations by clear-cutting leads to an enormous release of N2O from the soil into the atmosphere, not only during the first year after treatment, but for several consecutive years, and simultaneously to a marked reduction in the uptake capacity of the soil for CH4. Although selective cutting also enhances the source strength for N2O and reduces the CH4 sink strength, respectively, the effects are by far less pronounced as compared to clear-cutting. Establishing the total greenhouse gas balance (CH4, N2O, CO2) for a forest rotation time of 80 years by considering the huge differences in global warming potentials of these greenhouse gases revealed that the enhanced N2O emissions and reduced CH4 deposition rates due to different forest conversion practices can compensate CO2 sequestration benefits to a significant extent.

  7. Impact of postconsumer recycling initiatives on industrial energy demand-opportunities and threats for natural gas. Final report, December 1991-June 1993

    SciTech Connect

    Artz, N.; Kinkelaar, M.; Kirk, M.

    1993-01-01

    The rapid change in municipal solid waste and industrial waste management practices in the U.S. could have significant impact on industrial energy demand and ultimately, natural gas demand. The study examines the impact of increased rates of postconsumer recycling and waste used as fuel on industrial natural gas demand for the time period 1990 to 2005. Increased postconsumer recycling and waste used as fuel are projected to decrease natural gas demand in the U.S. by 29 trillion Btu per year by 1995 and over 71 trillion Btu by 2005. Increased ferrous scrap use in electric are furnaces and postconsumer plastics recycling are projected to cause the most significant loss in natural gas demand.

  8. Investigation of Controlling Factors Impacting Water Quality in Shale Gas Produced Brine

    NASA Astrophysics Data System (ADS)

    Fan, W.; Hayes, K. F.; Ellis, B. R.

    2014-12-01

    The recent boom in production of natural gas from unconventional reservoirs has generated a substantial increase in the volume of produced brine that must be properly managed to prevent contamination of fresh water resources. Produced brine, which includes both flowback and formation water, is often highly saline and may contain elevated concentrations of naturally occurring radioactive material and other toxic elements. These characteristics present many challenges with regard to designing effective treatment and disposal strategies for shale gas produced brine. We will present results from a series of batch experiments where crushed samples from two shale formations in the Michigan Basin, the Antrim and Utica-Collingwood shales, were brought into contact with synthetic hydraulic fracturing fluids under in situ temperature and pressure conditions. The Antrim has been an active shale gas play for over three decades, while the Utica-Collingwood formation (a grouped reservoir consisting of the Utica shale and Collingwood limestone) is an emerging shale gas play. The goal of this study is to investigate the influence of water-rock interactions in controlling produced water quality. We evaluate toxic element leaching from shale samples in contact with model hydraulic fracturing fluids under system conditions corresponding to reservoir depths up to 1.5 km. Experimental results have begun to elucidate the relative importance of shale mineralogy, system conditions, and chemical additives in driving changes in produced water quality. Initial results indicate that hydraulic fracturing chemical additives have a strong influence on the extent of leaching of toxic elements from the shale. In particular, pH was a key factor in the release of uranium (U) and divalent metals, highlighting the importance of the mineral buffering capacity of the shale. Low pH values persisted in the Antrim and Utica shale experiments and resulted in higher U extraction efficiencies than that observed in the presence of the carbonate-rich Collingwood limestone. In addition to assessing U leaching, we also measured the activity of 226Ra and 228Ra via high-resolution gamma ray spectroscopy. Laboratory results will be compared to observations from a complimentary field sampling campaign of Antrim produced brine.

  9. Cooking a `Sausage': the impact of merger shocks in cluster gas and galaxy evolution

    NASA Astrophysics Data System (ADS)

    Stroe, Andra; Sobral, David; Harwood, Jeremy; Van Weeren, Reinout J.; Rumsey, Clare; Intema, Huib; Röttgering, Huub; Brüggen, Marcus; Saunders, Richard; Hardcastle, Martin; Hoeft, Matthias

    2015-01-01

    Galaxy clusters mainly grow through mergers with other clusters and groups. Major mergers give rise to important astrophysical phenomena such as the segregation of dark and luminous matter and the formation of cluster-wide traveling shocks and also drive galaxy evolution. The observable effects of shock waves can be seen at radio wavelengths as relics: elongated, diffuse synchrotron emitting areas located at the periphery of merging clusters. Despite the great interest in relics, candidates with simple geometry, undisturbed morphology and high surface brightness are scarce. The `Sausage' cluster hosts an extraordinary Mpc-wide relic, which enables us to study to study particle acceleration and the effects of shocks on cluster galaxies. We use a unique combination of facilities (INT, WHT, Keck, Subaru, CFHT, GMRT, WSRT, AMI) to obtain the first cluster-wide, multi-wavelength, multi-method analysis aimed at giving a complete picture of a merging cluster with relics. Using the radio data, we derive shock properties and the magnetic field structure for the relic. Using spectral modeling, we test acceleration and electron energy-loss mechanisms and resolve the discrepancy between the Mach number calculated from the radio and X-rays. Our results indicate that particles are shock-accelerated, but turbulent re-acceleration or unusually efficient transport of particles in the downstream area and line-of-sight mixing are important effects. We demonstrate the feasibility of high-frequency observations of radio relics, by presenting a 16 GHz detection of the `Sausage' relic. The radio analysis is complemented by Hα mapping of the cluster volume, aimed at providing the first direct test as to whether the shock drives or prohibits star formation. We find numerous Hα emitting galaxies in close proximity to the radio relic which are extremely massive, metal-rich, mostly star-forming with evidence for gas mass loss though outflows. We speculate that the complex interaction between the merger, the shock wave and gas is a fundamental driver in the evolution of cluster galaxies from gas rich spirals to gas-poor ellipticals.

  10. The impact of emissions standards on the design of aircraft gas turbine engine combustors

    NASA Technical Reports Server (NTRS)

    Rudey, R. A.

    1976-01-01

    Effective emission control techniques have been identified and a wide spectrum of potential applications for these techniques to existing and advanced engines are being considered. Results from advanced combustor concept evaluations and from fundamental experiments are presented and discussed and comparisons are made with existing EPA emission standards and recommended levels for high altitude cruise. The impact that the advanced low emission concepts may impose on future aircraft engine combustor designs and related engine components is discussed.

  11. Quantifying the impact of nitric oxide calibration gas mixture oxidation on reported nitrogen dioxide concentrations

    NASA Astrophysics Data System (ADS)

    Sweeney, Bryan P.; Quincey, Paul G.; Green, David; Fuller, Gary W.

    2015-03-01

    Chemiluminescent analysers for measuring nitric oxide (NO) and nitrogen dioxide (NO2) in ambient air are generally calibrated with certified gas standard cylinders of NO in nitrogen. Verification of the NOx and NO amount fractions has been carried out on many such 'on-site' calibration cylinders at air quality monitoring stations. These measurements indicate that significant numbers of these gas mixtures have become somewhat degraded, with several percent of the NO oxidised to NO2. The effect of not compensating for this degradation on reported concentrations is discussed. If such degradation is not quantified and corrected for, there will be a systematic under-reporting of NO2 concentrations, which, due to the non-linearity of the effect, could reduce high reported NO2 concentrations at kerbside sites by around 20%. This could significantly reduce the number of reported exceedances of the NO2 limit value at such sites, compared to results obtained where there is no degradation of the NO cylinder.

  12. Impact on aviation operations of volcanic gas and ash clouds from the 2008 eruptions of Okmok and Kasatochi, Alaska

    NASA Astrophysics Data System (ADS)

    Guffanti, M.; Schneider, D. J.; Ewert, J. W.; Targosz, S.

    2008-12-01

    The eruptions of Okmok in July 2008 and Kasatochi in August 2008 both produced sulfur dioxide clouds notable for their dispersion over the northern conterminous United States. An aircraft encounter with the Okmok volcanic cloud occurred near Kodiak Island on 15 July, and some other flights were diverted north of normal air routes, but the overall impact on aviation of the Kasatochi eruption was greater. The 7 August 2008 eruption of Kasatochi sent an impressive amount of sulfur dioxide gas into the atmosphere, about 1.5 megatons according to S. Carn (this session), an order of magnitude greater than from Okmok. Preliminary estimates of Kasatochi's erupted volume range between 0.1 and 0.25 cubic kilometers (dense rock equivalent), making it one of the largest North American eruptions in the past 25 years. As Kasatochi's cloud dispersed over the Gulf of Alaska, Canada, and the northern conterminous United States, widespread disruptions to aviation operations occurred. On 10 August 2008 the ash/gas cloud passed over the southeast coast of Alaska, resulting in flight cancellations between Anchorage and Seattle, Portland, San Francisco, Denver, Los Angeles, and Vancouver BC and the stranding of a reported 6,000 passengers. The cancellations were primarily night flights, aa the airlines were concerned that pilots would not be able to visually identify the potentially hazardous volcanic cloud. As the cloud moved over Canada and parts of the United States, the area of sulfur dioxide detected by the satellite-borne Ozone Monitoring Instrument, while in accord with dispersion modeling by the Montreal Volcanic Ash Advisory Center, was much larger than the area of ash detected by the thermal infrared brightness-temperature-differencing (BTD) remote-sensing method. Concurrently, numerous pilot reports of sulfurous odors in the cockpit and visible brownish haze at cruise altitudes (the latter as late as two weeks after the eruption) suggested that sulfur dioxide gas had been converted to sulfur aerosols. Procedures for aircraft entry into volcanic ash clouds have been formulated, but procedures are not well specified for flying into large areas of sulfur dioxide gas and related aerosols. Airlines coped by flying over, under, and sometimes through the observable haze layer. Given the different types of data now available to detect and quantify ash, gas, and aerosols in the atmosphere, a focused scientific effort is needed to provide aviation users with integrated depictions of volcanic clouds so that appropriate operational procedures can be developed.

  13. Impacts of Application of Methane Fermentation Digested Liquid on Green House Gas Emissions and Nitrogen Leaching from Upland Field

    NASA Astrophysics Data System (ADS)

    Nakamura, Masato; Fujikawa, Tomonori; Yuyama, Yoshito; Maeda, Morihiro; Yamaoka, Masaru

    Nitrogen uptake by crops, green-house gas emissions and nitrogen leaching were studied by using monolith lysimeters applied with digested liquid or ammonium sulfate to evaluate the environmental impacts of applications of methane fermentation digested liquid on Andosol upland field. A two-year experiment indicated the percentages of nitrogen uptake, leached nitrogen and nitrous oxide (N2O) emissions to each material-derived nitrogen were 27%, 44% and 0.41% in the digested liquid plot and 32%, 46% and 0.11% in the ammonium sulfate plot. The results show that digested liquid is readily release fertilizer like ammonium sulfate, and nitrogen is leached as easily from the digested liquid as from the ammonium sulfate and the N2O emissions from the digested liquid plot are higher than from the ammonium sulfate plot.

  14. Assessing environmental impact from gas and oil exploration in the SW Barents Sea using benthic foraminiferal assemblages

    NASA Astrophysics Data System (ADS)

    Dijkstra, N.; Junttila, J.; Husum, K.; Carroll, J.; Hald, M.

    2012-04-01

    During the last decades petroleum industry and shipping activities have increased in the SW Barents Sea. Oil exploration wells were drilled in the 1980s with production starting in 2007. These activities are projected to expand in the coming years. As part of the Northern Environmental Waste Management (EWMA) project, a competence cluster for petroleum industry related waste handling, we investigate the impacts of enhanced anthropogenic activities on benthic foraminiferal assemblages in the SW Barents Sea. Sediment cores (0-20 cm) from sites in proximity to two oil- and gas fields are under investigation. These sediment cores, dated with the 210Pb method, represent the last 90 to 150 years. Both dead and living benthic foraminifera (100 µm-1 mm) were counted to elucidate differences in foraminiferal assemblages between pre-impact and recent conditions. In addition, the heavy metal concentrations, persistent organic pollutant (POP) concentrations, grain size and total organic content (TOC) of the sediment cores have been analyzed. Pollution levels of the surface sediments (0-1 cm) are of background to good level (level I-II) according to the definitions of the Water Framework Directorate (WFD). Patterns in living benthic foraminiferal assemblages identified in the sea floor surface sediments, are the result of natural environmental changes such as depth, water mass and sediment composition. Further downcore (1-20 cm) pollution levels are in general of background environmental status (WFD level I). However, at some depth intervals, especially in sediment cores from the near proximity of the oil- and gas- fields, pollution levels are slightly enhanced (WFD level II). Further work will include statistical comparison of dead and living foraminiferal assemblages with sediment pollution levels, sediment properties, and oceanographic conditions. This research contributes to the development of foraminifera as a useful bio-monitoring technique for the Arctic region as industrial activities increase in the coming years.

  15. Life cycle greenhouse gas impacts of ethanol, biomethane and limonene production from citrus waste

    NASA Astrophysics Data System (ADS)

    Pourbafrani, Mohammad; McKechnie, Jon; MacLean, Heather L.; Saville, Bradley A.

    2013-03-01

    The production of biofuel from cellulosic residues can have both environmental and financial benefits. A particular benefit is that it can alleviate competition for land conventionally used for food and feed production. In this research, we investigate greenhouse gas (GHG) emissions associated with the production of ethanol, biomethane, limonene and digestate from citrus waste, a byproduct of the citrus processing industry. The study represents the first life cycle-based evaluations of citrus waste biorefineries. Two biorefinery configurations are studied—a large biorefinery that converts citrus waste into ethanol, biomethane, limonene and digestate, and a small biorefinery that converts citrus waste into biomethane, limonene and digestate. Ethanol is assumed to be used as E85, displacing gasoline as a light-duty vehicle fuel; biomethane displaces natural gas for electricity generation, limonene displaces acetone in solvents, and digestate from the anaerobic digestion process displaces synthetic fertilizer. System expansion and two allocation methods (energy, market value) are considered to determine emissions of co-products. Considerable GHG reductions would be achieved by producing and utilizing the citrus waste-based products in place of the petroleum-based or other non-renewable products. For the large biorefinery, ethanol used as E85 in light-duty vehicles results in a 134% reduction in GHG emissions compared to gasoline-fueled vehicles when applying a system expansion approach. For the small biorefinery, when electricity is generated from biomethane rather than natural gas, GHG emissions are reduced by 77% when applying system expansion. The life cycle GHG emissions vary substantially depending upon biomethane leakage rate, feedstock GHG emissions and the method to determine emissions assigned to co-products. Among the process design parameters, the biomethane leakage rate is critical, and the ethanol produced in the large biorefinery would not meet EISA’s requirements for cellulosic biofuel if the leakage rate is higher than 9.7%. For the small biorefinery, there are no GHG emission benefits in the production of biomethane if the leakage rate is higher than 11.5%. Compared to system expansion, the use of energy and market value allocation methods generally results in higher estimates of GHG emissions for the primary biorefinery products (i.e., smaller reductions in emissions compared to reference systems).

  16. Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2.

    PubMed

    Zhou, Changjie; Yang, Weihuang; Zhu, Huili

    2015-06-01

    Density functional theory calculations were performed to assess changes in the geometric and electronic structures of monolayer WS2 upon adsorption of various gas molecules (H2, O2, H2O, NH3, NO, NO2, and CO). The most stable configuration of the adsorbed molecules, the adsorption energy, and the degree of charge transfer between adsorbate and substrate were determined. All evaluated molecules were physisorbed on monolayer WS2 with a low degree of charge transfer and accept charge from the monolayer, except for NH3, which is a charge donor. Band structure calculations showed that the valence and conduction bands of monolayer WS2 are not significantly altered upon adsorption of H2, H2O, NH3, and CO, whereas the lowest unoccupied molecular orbitals of O2, NO, and NO2 are pinned around the Fermi-level when these molecules are adsorbed on monolayer WS2. The phenomenon of Fermi-level pinning was discussed in light of the traditional and orbital mixing charge transfer theories. The impacts of the charge transfer mechanism on Fermi-level pinning were confirmed for the gas molecules adsorbed on monolayer WS2. The proposed mechanism governing Fermi-level pinning is applicable to the systems of adsorbates on recently developed two-dimensional materials, such as graphene and transition metal dichalcogenides. PMID:26049513

  17. Shot noise generated by gas impact during a cometary fly-by

    NASA Astrophysics Data System (ADS)

    Grard, R.

    1983-11-01

    The spectrum of shot noise detected by a satellite electric field sensor made of two spheres in the solar wind and at various distances from the nucleus of comet Halley is predicted. The interaction between the antenna and the cometary gas flow is analyzed. At low frequencies, the noise is dominated by the effect of escaping or collected particles, and the distribution varies. At intermediate frequencies, the role of the trapped particles is preponderant, and the spectrum is flat. At high frequencies, above the inverse bounce period, the noise spectrum decreases. The noise level can be reduced by using meshed probes which have a smaller collecting area. This approach is particularly efficient at frequencies 1 kHz for spheres 5 cm in radius; the antenna impedance is then mostly capacitive and a reduction of its conductance has no significant effect.

  18. The impact of oxygen on the morphology of gas-phase prepared Au nanoparticles

    SciTech Connect

    Pohl, D.; Surrey, A.; Schultz, L.; Rellinghaus, B.

    2012-12-24

    We present an easy procedure for the synthesis of single crystalline gold nanoparticles with a mean diameter of 4 nm using a DC-sputtering in an argon-oxygen gas mixture. Morphology population statistics have been determined to quantify the influence of oxygen. It is found that the particles undergo a structural transition from predominantly icosahedral to single crystalline particles with increasing amount of oxygen. Aberration-corrected high-resolution transmission electron microscopy investigation proves that likewise prepared single crystalline nanoparticles are defect and oxygen free. In contrast, the icosahedral particles prepared with pure argon show the presence of edge dislocations pointing to an energetic disfavoring already at these relatively small particle sizes. This morphology control of clean and uncovered Au nanoparticles provides a high application potential, e.g., for studying the influence of the particle morphology on plasmonic and catalytic properties.

  19. Low temperature impact toughness of the main gas pipeline steel after long-term degradation

    NASA Astrophysics Data System (ADS)

    Maruschak, Pavlo; Danyliuk, Iryna; Bishchak, Roman; Vuherer, Tomaž

    2014-12-01

    The correlation of microstructure, temperature and Charpy V-notch impact properties of a steel 17G1S pipeline steel was investigated in this study. Within the concept of physical mesomechanics, the dynamic failure of specimens is represented as a successive process of the loss of shear stability, which takes place at different structural/scale levels of the material. Characteristic stages are analyzed for various modes of failure, moreover, typical levels of loading and oscillation periods, etc. are determined. Relations between low temperature derived through this test, microstructures and Charpy (V-notch) toughness test results are also discussed in this paper.

  20. THE IMPACT OF COLD GAS ACCRETION ABOVE A MASS FLOOR ON GALAXY SCALING RELATIONS

    SciTech Connect

    Bouche, N.; Genzel, R.; Genel, S.; Cresci, G.; Foerster Schreiber, N. M.; Davies, R. I.; Tacconi, L.; Dekel, A.; Shapiro, K. L.

    2010-08-01

    Using the cosmological baryonic accretion rate and normal star formation (SF) efficiencies, we present a very simple model for star-forming galaxies that accounts for the mass and redshift dependences of the star formation rate (SFR)-mass and Tully-Fisher (TF) relations from z {approx} 2 to the present. The time evolution follows from the fact that each modeled galaxy approaches a steady state where the SFR follows the (net) cold gas accretion rate. The key feature of the model is a halo mass floor M {sub min} {approx_equal} 10{sup 11} M{sub sun} below which accretion is quenched in order to simultaneously account for the observed slopes of the SFR-mass and TF relations. The same successes cannot be achieved via an SF threshold (or delay) nor by varying the SF efficiency or the feedback efficiency. Combined with the mass ceiling for cold accretion due to virial shock heating, the mass floor M{sub min} explains galaxy 'downsizing', where more massive galaxies formed earlier and over a shorter period of time. It turns out that the model also accounts for the observed galactic baryon and gas fractions as a function of mass and time, and the cosmic SFR density, which are all resulting from the mass floor M {sub min}. The model helps us to understand that it is the cosmological decline of accretion rate that drives the decrease of cosmic SFR density between z {approx} 2 and z = 0 and the rise of the cosmic SFR density from z {approx} 6 to z {approx} 2 that allows us to put a constraint on our main parameter M {sub min} {approx_equal} 10{sup 11} M{sub sun}. Among the physical mechanisms that could be responsible for the mass floor, our view is that photoionization feedback (from first in situ hot stars) lowering the cooling efficiency is likely to play a large role.

  1. Volcanic gas emissions from Mount Erebus and their impact on the Antarctic environment

    SciTech Connect

    Zreda-Gostynska, G.; Kyle, P.R.; Finnegan, D.; Prestbo, K.M.

    1997-07-01

    Emission rates of SO{sub 2}, HCl, and HF from the active volcano Mount Erebus, Antarctica, increased between 1986 and 1991; SO{sub 2} from 7.7 to 25.9Ggyr{sup {minus}1}, HCl from 6.9 to 13.3Ggyr{sup {minus}1} and HF from 4.0 to 6.0Ggyr{sup {minus}1}. The emission rates of halogens from Mount Erebus are high relative to SO{sub 2} emissions and are accompanied by relatively high emissions of trace gases and aerosols (Na, K, As, Zn, In, As, Se, and Au). Many elements (S, Cl, and metals) found in the Erebus plume are common impurities in Antarctic snow. Using a model which assumes a homogeneous distribution of the volcanic gas plume over Antarctica, we suggest that Erebus could be a source of the impurities. We calculate that Erebus could potentially contribute between 4 and 14ngg{sup {minus}1} snow of Cl at the south pole, and between 11 and 36ngg{sup {minus}1} snow of Cl at Dome C. Excess Cl (Cl in excess of that derived from marine NaCl aerosols) recorded in snow and firn cores from south pole and Dome C could be mainly derived from Erebus. Similarly, our predicted concentrations of Erebus-derived Cu, Zn, Cd, V, As, and Au in Antarctic snow are close to those reported. Trace element and Pb isotope compositions of Erebus aerosols are similar to those collected in remote regions of Antarctica. The volcanic gas plume emitted from Erebus appears to make a significant contribution to the Antarctic atmosphere and can be detected in the snow deposited over a wide area of the continent.{copyright} 1997 American Geophysical Union

  2. European greenhouse gas fluxes from land use: the impact of expanding the use of dedicated bioenergy crops.

    NASA Astrophysics Data System (ADS)

    Hastings, Astley; Böttcher, Hannes; Clifton-Brown, John; Fuchs, Richard; Hillier, Jon; Jones, Ed; Obersteiner, Michael; Pogson, Mark; Richards, Mark; Smith, Pete

    2013-04-01

    Bioenergy derived from vegetation cycles carbon to and from the atmosphere using the chemical energy fixed by the plants by photosynthesis using solar energy. However bioenergy is not carbon neutral as energy is used and greenhouse gasses (GHG) are emitted in the process of growing bioenergy feeedstocks and processing them into a usable fuel, whether it is biomass or liquid fuel such as biodiesel or bioethanol. Using bio instead of fossil fuels replaces greenhouse gas emissions from coal, oil and gas by those of the biofuel. To estimate the impact on European greenhouse gas fluxes of expanding the use of bioenergy, it is necessary to quantify the difference between the GHG emissions associated with producing and using the biofuel and the fossil fuel it replaces, and to take into account any emissions associated with the change from the original land use to that of growing the bioenergy feedstock. This involves estimating any displacement of food, fibre and timber production to other geographical areas. Here we report on a study of the GHG emissions from the potential increasing use of a variety of biofuels produced from feedstocks grown in the EU countries. The GHG emissions of the historical land use of EU27 have been modelled using ECOSSE on a 1 km grid to estimate the impact the agriculture intensification and land use change of the last 50 years and the associated crop yield gains. The excess land made available from the yield gains is considered to be available for use for bioenergy, and the yields of potential bioenergy feedstocks are estimated from EUROSTAT data or modelled using the bioenergy crop growth model MISCANFOR. These yields are used to calculate the energy used and GHG emissions associated with the use of the resulting biofuel using a life cycle analysis, and to estimate the organic matter input into the soil. The ECOSSE model is then used to estimate the soil carbon change and GHG emissions associated with the land use change to growing the bioenergy feedstock. This data has been used to quantify the net change in GHG emissions and the quantity of energy produced. We conclude that home grown bioenergy will be a modest contributor to both GHG emission reduction and energy demand.

  3. Greenhouse gas emission impacts of alternative-fueled vehicles: Near-term vs. long-term technology options

    SciTech Connect

    Wang, M.Q.

    1997-12-31

    The U.S. transportation sector produces nearly one-third of total U.S. greenhouse gas (GHG) emissions. Among various transportation control strategies evaluated in the U.S., use of vehicles fueled with alternative fuels has been proposed to help solve urban air pollution problems, reduce U.S. dependence on imported oil, and reduce transportation GHG emissions. GHG emission impacts of alternative-fueled vehicles depend on type of fuels used, type of primary energy sources used to produce the fuels, and energy efficiencies of vehicles and up-stream energy production activities. Past studies have shown widely-varied, sometimes contradicting, results of GHG emissions by alternative-fueled vehicles. A fuel-cycle model has been developed at Argonne National Laboratory to estimate fuel-cycle emissions and energy consumption of various alternative-fueled vehicles. The model, called Greenhouse Gases, Regulated Emissions, and Energy use in Transportation (GREET), calculates fuel-cycle emissions of five criteria pollutants (volatile organic compounds, carbon monoxide, nitrogen oxides, sulfur oxides, and particulate matter) and three greenhouse gases (carbon dioxide, methanol, and nitrous oxide). In this paper, the GREET will be used to estimate fuel-cycle GHG emission impacts of near-term and long-term alternative-fueled vehicle technology options.

  4. Free and forced convection in high permeability soils: impact on gas flux at the soil-atmosphere interface

    NASA Astrophysics Data System (ADS)

    Levintal, E.; Dragila, M. I.; Weisbrod, N.

    2013-12-01

    In low permeability soils, gas flux is mostly governed by diffusion and considered to be a relatively slow and continuous process of soil ventilation and aeration. Recent studies have shown that as the soil permeability increases, gas circulation by convective mechanisms become important. In high permeability matrices, the overall gas flux through the earth-atmosphere interface can be significantly greater than the diffusive gas flux. There are several driving mechanisms which can trigger convective gas exchange at the earth - atmosphere interface, two of those can be of great importance and are being explored in this research. The first one is thermal convection venting (TCV), which develops when there are unstable density gradients. The second mechanism is wind induced convection (WIC), which develops due to surface winds that create pressure differences, thus driving air movement. Development of TCV and WIC are directly affected by soil properties, mostly soil permeability. The objectives of this research are to investigate: (a) the effect of porous media grain size, and the resulting permeability, on TCV and WIC, under homogeneous (one grain size) and simple heterogeneous (two grain sizes) conditions; and (b) the effect of atmospheric conditions on TCV and WIC, and mixed venting on the overall gas flux. The experiments were carried out in a Climate Controlled Laboratory using large columns packed with different ideal spherical particles and under different environmental conditions. Both wind and thermal gradients are imposed and controlled independently in order to isolate the different atmospheric effects. A network of sensors enables continuous monitoring of gas flux and thermal gradient inside the columns. A continuous low flow of CO2 enriched air enables constant CO2 concentration at the bottom of the column. Preliminary results show that in homogenous porous media with high permeability of 6.67 * 10-6 [m^2], using 4-cm diameter spheres, CO2 fluxes were significantly higher under WIC and TCV conditions compared to no-wind, isothermal conditions. Under WIC, surface wind speed of 1.5 [m/s], CO2 flux was 4.20.6 [g/m^2h]. Under TCV, with a temperature gradient of 8.8 [C/m], CO2 flux was 11.150.05 [g/m^2h]. Under no-wind isothermal conditions the measured flux was 2.450.6 [g/m^2h]. The CO2 flux was the highest when both WIC and TCV conditions were imposed simultaneously (14.61.1 [g/m^2h]), suggesting a superposition of the TCV and WIC mechanisms. In the layered heterogeneity experiment, still in process, preliminary results suggest the lower permeability layer is acting as the limiting factor for the TCV and WIC fluxes, (e.g., smaller particles of 1 cm over 4 cm in diameter). Initial results indicate that there is a permeability threshold value, which can be accurately determined and compared to models, above which TCV and WIC will occur and impact fluxes either independently or in conjunction depending on atmospheric conditions.

  5. Application of nonparametric regression and statistical testing to identify the impact of oil and natural gas development on local air quality

    NASA Astrophysics Data System (ADS)

    Cheng, Hanqi; Small, Mitchell J.; Pekney, Natalie J.

    2015-10-01

    The objective of the current work was to develop a statistical method and associated tool to evaluate the impact of oil and natural gas exploration and production activities on local air quality. Nonparametric regression of pollutant concentrations on wind direction was combined with bootstrap hypothesis testing to provide statistical inference regarding the existence of a local/regional air quality impact. The block bootstrap method was employed to address the effect of autocorrelation on test significance. The method was applied to short-term air monitoring data collected at three sites within Pennsylvania's Allegheny National Forest. All of the measured pollutant concentrations were well below the National Ambient Air Quality Standards, so the usual criteria and methods for data analysis were not sufficient. Using advanced directional analysis methods, test results were first applied to verify the existence of a regional impact at a background site. Next the impact of an oil field on local NOx and SO2 concentrations at a second monitoring site was identified after removal of the regional effect. Analysis of a third site also revealed air quality impacts from nearby areas with a high density of oil and gas wells. All results and conclusions were quantified in terms of statistical significance level for the associated inferences. The proposed method can be used to formulate hypotheses and verify conclusions regarding oil and gas well impacts on air quality and support better-informed decisions for their management and regulation.

  6. Greenhouse gas exchange in grasslands: impacts of climate, intensity of management and other factors

    NASA Astrophysics Data System (ADS)

    Smith, K. A.

    2003-04-01

    Grasslands occupy some 40% of the terrestrial land surface. They are generally categorised as natural (occurring mainly in those regions where the rainfall is too low to support forest ecosystems), semi-natural (where management, mainly by grazing, has changed the vegetation composition), and artificial (where forests have been cleared to create new pasture land). The soils of the natural and semi-natural grasslands constitute a large reservoir of carbon, and make a substantial contribution to the soil sink for atmospheric CH_4. The conversion of much of the natural temperate grassland to arable agriculture, e.g. in North America and Europe, resulted in a considerable decrease in soil organic carbon, and its release to the atmosphere as CO_2 has made a substantial contribution to the total atmospheric concentration of this gas. The associated increase in cycling of soil N (released from the organic matter) will have contributed to N_2O emissions, and land disturbance and fertilisation has resulted in a depletion of the soil CH_4 sink. Conversion of tropical forests to pastures has also been a major source of CO_2, and these pastures show elevated emissions of N_2O for some years after conversion. Seasonally flooded tropical grasslands are a significant source of CH_4 emissions. Consideration of grassland ecosystems in their entirety, in relation to GHG exchange, necessitates the inclusion of CH_4 production by fauna - domesticated livestock and wild herbivores, as well as some species of termites - in the overall assessment. Stocking rates on pasture land have increased, and the total CH_4 emissions likewise. The relationship between animal production and CH_4 emissions is dependent on the nutritional quality of the vegetation, as well as on animal numbers. In both temperate and tropical regions, increased N inputs as synthetic fertilisers and manures (and increased N deposition) are producing possibly a more-than-linear response in terms of emissions of N_2O. In several Western European countries, very high rates of N application to both grazed grassland and to grass crops grown for winter feed have made these lands the principal source of N_2O. It has been estimated that 40% of global emissions of NO, a precursor of tropospheric ozone, come from grasslands and savannas. Global warming is expected to bring about substantial changes in the overall greenhouse gas exchange of grasslands, with a net loss of soil C as CO_2, and possibly enhanced N_2O emissions. Increased rainfall is predicted for some regions, and this can also be expected to give rise to increases in N_2O.

  7. Water Resource Impacts During Unconventional Shale Gas Development: The Pennsylvania Experience

    NASA Astrophysics Data System (ADS)

    Brantley, S. L.; Yoxtheimer, D.; Arjmand, S.; Grieve, P.; Vidic, R.; Abad, J. D.; Simon, C. A.; Pollak, J.

    2013-12-01

    The number of unconventional Marcellus shale wells in PA has increased from 8 in 2005 to more than 6000 today. This rapid development has been accompanied by environmental issues. We analyze publicly available data describing this Pennsylvania experience (data from www.shalenetwork.org and PA Department of Environmental Protection, i.e., PA DEP). After removing permitting and reporting violations, the average percent of wells/year with at least one notice of violation (NOV) from PA DEP is 35 %. Most violations are minor. An analysis of NOVs reported for wells drilled before 2013 revealed a rate of casing, cement, or well construction issues of 3.4%. Sixteen wells were given notices specifically related to migration of methane. A similarly low percent of wells were contaminated by brine components. Such contamination could derive from spills, subsurface migration of flowback water or shallow natural brines, or contamination by drill cuttings. Most cases of contamination of drinking water supplies with methane or brine components were reported in the previously glaciated part of the state. Before 2011, flowback and production water was often discharged legally into streams after minimal treatment, possibly increasing dissolved Br concentrations in some rivers. The rate of large spills or releases of gas-related industrial wastes in the state peaked in 2009 but little evidence of spills has been found in publicly available surface water chemistry data. The most likely indicators of spillage or subsurface release of flowback or production waters are the dissolved ions Na, Ca, and Cl. However, the data coverage for any given analyte is generally spatially and temporally sparse. Publicly available water quality data for before and after spills into Larrys Creek and Bobs Creek document the difficulties of detecting such events. An observation from the Pennsylvania experience is that the large number of people who have complained about their water supply (~1000 letters investigated by state regulators) and the media attention during the fast start in PA may have led to better management practices. Maintaining online databases of observations could similarly drive shale-gas practice to become even more environmentally protective.

  8. Contact lens impact on quality of life in keratoconus patients: rigid gas permeable versus soft silicone-hydrogel keratoconus lenses

    PubMed Central

    Yildiz, Elvin Hatice; Erdurmus, Mesut; Elibol, Emine Savran; Acar, Banu; Vural, Ece Turan

    2015-01-01

    AIM To determine the impact of rigid gas permeable (RGP) and silicone-hydrogel keratoconus lenses on the quality of life (QoL) in keratoconus (KCN) patients using the self-reported results from the Contact Lens Impact on Quality of Life (CLIQ) Questionnaire. METHODS From January 2013 to April 2013, 27 consecutive KCN patients who wore RGP contact lenses (conflexair100 UV KE Zeiss-Wöhlk) or soft silicone-hydrogel contact lenses (SHCLs) for KCN (KeraSoft IC- Bausch&Lomb or Hydrocone Toris K–Swiss lens) completed the CLIQ questionnaire. RESULTS The mean age of 27 patients was 29.6±8.0y. Fifteen patients were RGP user. The groups were comparable with respect to the mean patient age, sex, and mean K values (P=0.1, P=0.8 and P=0.1, respectively). The mean CLIQperson measure was 42.8±5.5 in RGP group and 39.6±5.5 in SHCLs for KCN group (P=0.06). CLIQperson measure was positively correlated with steep K value (r=0.301, P=0.04). When eyes were stratified by visual acuity with contact lenses, the mean CLIQperson measure was 42.01±5.6 in eyes with a visual acuity of 20/20-20/25 (n=44) and 38.4±5.26 in eyes with a visual acuity of 20/32 or less (n=10; P=0.097). CONCLUSION RGP lenses and SHCLs for KCN have similar impact on QoL. PMID:26558228

  9. Gas Gun Impact Testing of PZT 95/5, Part 1: Unpoled State

    SciTech Connect

    FURNISH,MICHAEL D.; SETCHELL,ROBERT E.; CHHABILDAS,LALIT C.; MONTGOMERY,STEPHEN T.

    2000-01-01

    In the present study, 10 impact tests were conducted on unpoled PZT 95/5, with 9% porosity and 2 at% Nb doping. These tests were instrumented to obtain time-resolved loading, unloading and span signatures. As well, PVDF gauges allowed shock timing to be established explicitly. The ferroelectric/antiferroelectric phases transition was manifested as a ramp to 0.4 GPa. The onset of crushup produced the most visible signature: a clear wave separation at 2.2 GPa followed by a highly dispersive wave. The end states also reflected crushup, and are consistent with earlier data and with related poled experiments. A span strength value of 0.17 GPa was measured for a shock stress of 0.5 GPa, this decreased to a very small value (no visible pullback signature) for a shock strength of 1.85 GPa.

  10. Impact of process design on greenhouse gas (GHG) generation by wastewater treatment plants.

    PubMed

    Bani Shahabadi, M; Yerushalmi, L; Haghighat, F

    2009-06-01

    The overall on-site and off-site greenhouse gas emissions by wastewater treatment plants (WWTPs) of food processing industry were estimated by using an elaborate mathematical model. Three different types of treatment processes including aerobic, anaerobic and hybrid anaerobic/aerobic processes were examined in this study. The overall on-site emissions were 1952, 1992, and 2435 kg CO2e/d while the off-site emissions were 1313, 4631, and 5205 kg CO2e/d for the aerobic, anaerobic and hybrid treatment systems, respectively, when treating a wastewater at 2000 kg BOD/d. The on-site biological processes made the highest contribution to GHG emissions in the aerobic treatment system while the highest emissions in anaerobic and hybrid treatment systems were obtained by off-site GHG emissions, mainly due to on-site material usage. Biogas recovery and reuse as fuel cover the total energy needs of the treatment plants for aeration, heating and electricity for all three types of operations, and considerably reduce GHG emissions by 512, 673, and 988 kg CO2e/d from a total of 3265, 6625, and 7640 kg CO2e/d for aerobic, anaerobic, and hybrid treatment systems, respectively. Considering the off-site GHG emissions, aerobic treatment is the least GHG producing type of treatment contrary to what has been reported in the literature. PMID:19375775

  11. Gulf of Mexico OCS oil and gas lease sales 171, 174, 177, and 180. Western planning area. Draft environmental impact statement

    SciTech Connect

    1997-10-01

    This EIS is a description of the environmental aspects and impacts of oil and gas activities resultig from these lease sales or the states bordering the Gulf of Mexico. It provides a description the proposed actions, issues and areas of concern, and the major differences of holding these lease sales.

  12. Gulf of Mexico OCS oil and gas lease sales 169, 172, 175, 178, and 182. Central planning area. Final environmental impact statement

    SciTech Connect

    1997-11-01

    This EIS is a description of the environmental aspects and impacts of oil and gas activities resultig from these lease sales or the states bordering the Gulf of Mexico. It provides a description of the areas, the affected environment, and the environmental consequences; It also discusses the proposed actions, issues and areas of concern, and the major differences of holding these lease sales.

  13. DESIGNING AND CONDUCTING WORKSHOPS: LESSONS FROM A TWO-YEAR PROJECT (ONSHORE IMPACTS OF OUTER CONTINENTAL SHELF OIL AND GAS DEVELOPMENT: A TRAINING PROJECT)

    EPA Science Inventory

    The report describes the process of developing and conducting two series of workshops on 'Onshore Impact of Outer Continental Shelf Oil and Gas Development'. The purpose of this report is to evaluate the workshops from the standpoint of their objectives, content, teaching methods...

  14. Impacts from oil and gas produced water discharges on the gulf of Mexico hypoxic zone.

    SciTech Connect

    Parker, M. E.; Satterlee, K.; Veil, J. A.; Environmental Science Division; ExxonMobil Production Co.; Shell Offshore

    2006-01-01

    Shallow water areas of the Gulf of Mexico continental shelf experience low dissolved oxygen (hypoxia) each summer. The hypoxic zone is primarily caused by input of nutrients from the Mississippi and Atchafalaya Rivers. The nutrients stimulate the growth of phytoplankton, which leads to reduction of the oxygen concentration near the sea floor. During the renewal of an offshore discharge permit used by the oil and gas industry in the Gulf of Mexico, the U.S. Environmental Protection Agency (EPA) identified the need to assess the potential contribution from produced water discharges to the occurrence of hypoxia. The EPA permit required either that all platforms in the hypoxic zone submit produced water samples, or that industry perform a coordinated sampling program. This paper, based on a report submitted to EPA in August 2005 (1), describes the results of the joint industry sampling program and the use of those results to quantify the relative significance of produced water discharges in the context of other sources on the occurrence of hypoxia in the Gulf of Mexico. In the sampling program, 16 facilities were selected for multiple sampling - three times each at one month intervals-- and another 34 sites for onetime sampling. The goal of the sampling program was to quantify the sources and amount of oxygen demand associated with a variety of Gulf of Mexico produced waters. Data collected included direct oxygen demand measured by BOD5 (5-day biochemical oxygen demand) and TOC (total organic carbon) and indirect oxygen demand measured by nitrogen compounds (ammonia, nitrate, nitrate, and TKN [total Kjeldahl nitrogen]) and phosphorus (total phosphorus and orthophosphate). These data will serve as inputs to several available computer models currently in use for forecasting the occurrence of hypoxia in the Gulf of Mexico. The output of each model will be compared for consistency in their predictions and then a semi-quantitative estimate of the relative significance of produced water inputs to hypoxia will be made.

  15. Impact of reduced tillage on the greenhouse gas balance - a meta-analysis

    NASA Astrophysics Data System (ADS)

    Don, Axel; Jantz, Marc

    2013-04-01

    Minimum tillage and no-tillage has been acknowledged as human induced measure for climate mitigation due to its potential to sequester additional soil carbon. However, there is increasing evidence that reduced tillage affects the vertical distribution of carbon in the soil profile, but hardy increases soil carbon stocks. Additionally, reduced tillage may increase the N2O emissions that would counterbalance the positive effects of soil carbon sequestration. Here we present a new meta-analysis on the full field scale effect of reduced tillage and no-tillage for the temperate zone including soil organic carbon, N2O and diesel derived fossil fuel emissions for field management. This analysis was performed using strict selection criteria and included data from more than 115 sites on soil carbon stock changes and from more than 30 sites with measured N2O fluxes on paired fields with conventional and reduced tillage. Soil organic carbon stocks did hardly increase (mean ±standard deviation: 2 ±11 Mg C ha-1) under no tillage as compared to moldboard ploughing. At 38% of all sites decreasing soil carbon stocks were detected under no-tillage as compared to conventional tillage. On the other hand, N2O emissions increased by around 40% on no-tillage fields with large deviations between sites. Thus, the total greenhouse gas balance turned out to be more negative for most no-tillage fields as compared to conventional tillage fields. The large observed scatter and deviations between sites and their controlling factors are discussed.

  16. Greenhouse gas emissions from MSW incineration in China: Impacts of waste characteristics and energy recovery

    SciTech Connect

    Yang Na; Zhang Hua; Chen Miao; Shao Liming; He Pinjing

    2012-12-15

    Determination of the amount of greenhouse gas (GHG) emitted during municipal solid waste incineration (MSWI) is complex because both contributions and savings of GHGs exist in the process. To identify the critical factors influencing GHG emissions from MSWI in China, a GHG accounting model was established and applied to six Chinese cities located in different regions. The results showed that MSWI in most of the cities was the source of GHGs, with emissions of 25-207 kg CO{sub 2}-eq t{sup -1} rw. Within all process stages, the emission of fossil CO{sub 2} from the combustion of MSW was the main contributor (111-254 kg CO{sub 2}-eq t{sup -1} rw), while the substitution of electricity reduced the GHG emissions by 150-247 kg CO{sub 2}-eq t{sup -1} rw. By affecting the fossil carbon content and the lower heating value of the waste, the contents of plastic and food waste in the MSW were the critical factors influencing GHG emissions of MSWI. Decreasing food waste content in MSW by half will significantly reduce the GHG emissions from MSWI, and such a reduction will convert MSWI in Urumqi and Tianjin from GHG sources to GHG sinks. Comparison of the GHG emissions in the six Chinese cities with those in European countries revealed that higher energy recovery efficiency in Europe induced much greater reductions in GHG emissions. Recovering the excess heat after generation of electricity would be a good measure to convert MSWI in all the six cities evaluated herein into sinks of GHGs.

  17. Fragmentation of saturated perfluorocarbon gas dielectrics under low-energy-electron impact

    SciTech Connect

    Spyrou, S.M.; Sauers, I.; Christophorou, L.G.

    1982-01-01

    We have proposed earlier the use of perfluorocarbons (PFCs) in combination with other gases for application as insulators in high voltage equipment. The potential use of these compounds requires knowledge of the effects resulting from electron impact in the 0 to 10 eV energy range (a region in which the preponderance of electron energies lie prior to breakdown). Electrons in this energy range attach to molecules either nondissociatively (e + AX ..-->.. AX/sup -/) or dissociatively (e + AX ..-->.. A/sup -/ + X). The stability of the molecule toward low-energy electrons depends on which mode of attachment predominates. We have studied previously a number of cyclic and unsaturated PFCs of dielectric interest. Saturated perfluoroalkanes, having the form n-C/sub N/F/sub 2N + 2/ with N = 3 to 6, are also attractive for this purpose (C/sub 3/F/sub 8/ and n-C/sub 4/F/sub 10/ for example, have dc uniform breakdown strengths of, respectively, 90 and 130% that of SF/sub 6/). We have, thus, undertaken a systematic study of these compounds using the electron swarm and the electron beam (by time-of-flight mass spectrometry) methods. The results obtained with the latter method are reported and discussed. Results obtained by the former method have been reported earlier.

  18. Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissions

    NASA Astrophysics Data System (ADS)

    Hutley, L. B.; Evans, B. J.; Beringer, J.; Cook, G. D.; Maier, S. M.; Razon, E.

    2013-12-01

    North Australian tropical savanna accounts for 12% of the worlds total savanna land cover. Accordingly, understanding processes that govern carbon, water and energy exchange within this biome is critical to global carbon and water budgeting. Climate and disturbances drive ecosystem carbon dynamics. Savanna ecosystems of the coastal and sub-coastal of north Australia experience a unique combination of climatic extremes and are in a state of near constant disturbance from fire events (1 in 3 years), storms resulting in windthrow (1 in 5-10 years) and mega-cyclones (1 in 500-1000 years). Critically, these disturbances occur over large areas creating a spatial and temporal mosaic of carbon sources and sinks. We quantify the impact on gross primary productivity (GPP) and fire occurrence from a tropical mega-cyclone, tropical Cyclone Monica (TC Monica), which affected 10?400 km2 of savanna across north Australia, resulting in the mortality and severe structural damage to 140 million trees. We estimate a net carbon equivalent emission of 43 Tg of CO2-e using the moderate resolution imaging spectroradiometer (MODIS) GPP (MOD17A2) to quantify spatial and temporal patterns pre- and post-TC Monica. GPP was suppressed for four years after the event, equivalent to a loss of GPP of 0.5 Tg C over this period. On-ground fuel loads were estimated to potentially release 51.2 Mt CO2-e, equivalent to 10% of Australias accountable greenhouse gas emissions. We present a simple carbon balance to examine the relative importance of frequency versus impact for a number of key disturbance processes such as fire, termite consumption and intense but infrequent mega-cyclones. Our estimates suggested that fire and termite consumption had a larger impact on Net Biome Productivity than infrequent mega-cyclones. We demonstrate the importance of understanding how climate variability and disturbance impacts savanna dynamics in the context of the increasing interest in using savanna landscapes for enhanced carbon sinks in emission offset schemes.

  19. Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

    NASA Astrophysics Data System (ADS)

    Järveoja, J.; Peichl, M.; Maddison, M.; Soosaar, K.; Vellak, K.; Karofeld, E.; Teemusk, A.; Mander, Ü.

    2015-10-01

    Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting water table levels (WTL) on the annual C and GHG balances of restoration treatments with high (Res-H) and low (Res-L) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in Res-H relative to Res-L. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in Res-L compared to Res-H. However, the means of the measured net ecosystem CO2 exchanges (NEE) were not significantly different between Res-H and Res-L. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges in Res-H and Res-L, respectively. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, Res-H, Res-L and BP were C sources of 111, 103 and 268 g C m-2 yr-1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha-1 yr-1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments three years following restoration. However, the C and GHG balances in Res-H and Res-L were considerably lower than in BP owing to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.

  20. Evaluating Impacts of CO2 Gas Intrusion Into a Confined Sandstone aquifer: Experimental Results

    SciTech Connect

    Qafoku, Nikolla; Lawter, Amanda R.; Shao, Hongbo; Wang, Guohui; Brown, Christopher F.

    2014-12-31

    Deep subsurface storage and sequestration of CO2 has been identified as a potential mitigation technique for rising atmospheric CO2 concentrations. Sequestered CO2 represents a potential risk to overlying aquifers if the CO2 leaks from the deep storage reservoir. Experimental and modeling work is required to evaluate potential risks to groundwater quality and develop a systematic understanding of how CO2 leakage may cause important changes in aquifer chemistry and mineralogy by promoting dissolution/precipitation, adsorption/desorption, and redox reactions. Sediments from the High Plains aquifer in Kansas, United States, were used in this investigation, which is part of the National Risk Assessment Partnership Program sponsored by the US Department of Energy. This aquifer was selected to be representative of consolidated sand and gravel/sandstone aquifers overlying potential CO2 sequestration repositories within the continental US. In this paper, we present results from batch experiments conducted at room temperature and atmospheric pressure with four High Plains aquifer sediments. Batch experiments simulate sudden, fast, and short-lived releases of the CO2 gas as would occur in the case of well failure during injection. Time-dependent release of major, minor, and trace elements were determined by analyzing the contacting solutions. Characterization studies demonstrated that the High Plains aquifer sediments were abundant in quartz and feldspars, and contained about 15 to 20 wt% montmorillonite and up to 5 wt% micas. Some of the High Plains aquifer sediments contained no calcite, while others had up to about 7 wt% calcite. The strong acid extraction tests confirmed that in addition to the usual elements present in most soils, rocks, and sediments, the High Plains aquifer sediments had appreciable amounts of As, Cd, Pb, Cu, and occasionally Zn, which potentially may be mobilized from the solid to the aqueous phase during or after exposure to CO2. However, the results from the batch experiments showed that the High Plains sediments mobilized only low concentrations of trace elements (potential contaminants), which were detected occasionally in the aqueous phase during these experiments. Importantly, these occurrences were more frequent in the calcite-free sediment. Results from these investigations provide useful information to support site selection, risk assessment, and public education efforts associated with geological CO2 storage and sequestration.

  1. Evaluating Impacts of CO2 Gas Intrusion Into a Confined Sandstone aquifer: Experimental Results

    DOE PAGESBeta

    Qafoku, Nikolla; Lawter, Amanda R.; Shao, Hongbo; Wang, Guohui; Brown, Christopher F.

    2014-12-31

    Deep subsurface storage and sequestration of CO2 has been identified as a potential mitigation technique for rising atmospheric CO2 concentrations. Sequestered CO2 represents a potential risk to overlying aquifers if the CO2 leaks from the deep storage reservoir. Experimental and modeling work is required to evaluate potential risks to groundwater quality and develop a systematic understanding of how CO2 leakage may cause important changes in aquifer chemistry and mineralogy by promoting dissolution/precipitation, adsorption/desorption, and redox reactions. Sediments from the High Plains aquifer in Kansas, United States, were used in this investigation, which is part of the National Risk Assessment Partnershipmore » Program sponsored by the US Department of Energy. This aquifer was selected to be representative of consolidated sand and gravel/sandstone aquifers overlying potential CO2 sequestration repositories within the continental US. In this paper, we present results from batch experiments conducted at room temperature and atmospheric pressure with four High Plains aquifer sediments. Batch experiments simulate sudden, fast, and short-lived releases of the CO2 gas as would occur in the case of well failure during injection. Time-dependent release of major, minor, and trace elements were determined by analyzing the contacting solutions. Characterization studies demonstrated that the High Plains aquifer sediments were abundant in quartz and feldspars, and contained about 15 to 20 wt% montmorillonite and up to 5 wt% micas. Some of the High Plains aquifer sediments contained no calcite, while others had up to about 7 wt% calcite. The strong acid extraction tests confirmed that in addition to the usual elements present in most soils, rocks, and sediments, the High Plains aquifer sediments had appreciable amounts of As, Cd, Pb, Cu, and occasionally Zn, which potentially may be mobilized from the solid to the aqueous phase during or after exposure to CO2. However, the results from the batch experiments showed that the High Plains sediments mobilized only low concentrations of trace elements (potential contaminants), which were detected occasionally in the aqueous phase during these experiments. Importantly, these occurrences were more frequent in the calcite-free sediment. Results from these investigations provide useful information to support site selection, risk assessment, and public education efforts associated with geological CO2 storage and sequestration.« less

  2. Impact of energy maize cultivation and erosion on carbon gas exchange and soil organic carbon budgets in young moraine landscapes

    NASA Astrophysics Data System (ADS)

    Pohl, M.; Hagemann, U.; Liebe, M.; Sommer, M.; Augustin, J.

    2012-04-01

    The hilly young moraine landscape of north-eastern Germany is dominated by the cultivation of energy crops like maize. It is suspected that this cultivation can increase erosion effects and lead to the release of soil carbon (C). Therefore, in an interdisciplinary approach, the CarboZALF project investigates the impact of various factors such as erosion on greenhouse gas (GHG) fluxes and C dynamics on the site and the landscape level. From the CarboZalf-D project site located in the Uckermark, we present measured and modeled GHG fluxes (CO2 and CH4) and C dynamics of maize on four erosion-related soil types: a) haplic luvisol, b) eroded haplic luvisol, c) haplic regosol (calcaric) and d) endogleyic colluvic regosol. CO2 flux measurements of ecosystem respiration (Reco) and net ecosystem exchange (NEE) were conducted every four weeks by using a non-flow-through non-steady-state closed chamber system (Livingston and Hutchinson 1995) based on Drsler (2005). Measurement gaps of NEE were filled by modeling the Reco fluxes using the Lloyd-Taylor (Lloyd and Taylor 1994) method and the gross primary production (GPP) fluxes using Michaelis-Menten (Michaelis and Menten 1913) modeling approach. Annual NEE balances were then calculated based on the modeled Reco and GPP fluxes. CH4 fluxes were measured bi-weekly using a static chamber system with interval sampling. The system C budget is the sum of annual NEE, C export and CH4-C values. The endogleyic colluvic regosol featured the highest uptake of CH4 (< 1 kg C ha-1 yr-1), but the impact of erosion on the cumulative CH4 fluxes was very small. However, erosion and deposition had a significant impact on GPP, NEE and the C export, but with little differences between the resulting annual C balances. All investigated soil types were C sinks, storing 620 - 2600 kg C ha-1 yr-1. We conclude that i) maize cultivation must not be accompanied by soil organic carbon loss; ii) erosion seems to cause spatial variability of GHG fluxes and soil organic carbon budgets at least at the site level. Due to the temporal variability of GHG fluxes, generalized conclusions are only possible after long term investigations. This also applies to the question concerning the degree to which erosion influences C dynamics at the landscape scale. Drsler, M. 2005. Trace Gas Exchange and climatic relevance of bog ecosystems, Southern Germany, phD-thesis, TU Mnchen, Mnchen Livingston, G.P. & Hutchinson, G.L. 1995. Enclosure-based measurement of trace gas exchange: Applications and sources of error. p. 14-51. In P.A. Matson & Harriss, R.C. (ed.) Methods in ecology - Biogenic trace gases: Measuring emissions from soil and water. Blackwell Science, Oxford, England

  3. Unravelling the impact of hydrocarbon structure on the fumarate addition mechanism--a gas-phase ab initio study.

    PubMed

    Bharadwaj, Vivek S; Vyas, Shubham; Villano, Stephanie M; Maupin, C Mark; Dean, Anthony M

    2015-02-14

    The fumarate addition reaction mechanism is central to the anaerobic biodegradation pathway of various hydrocarbons, both aromatic (e.g., toluene, ethyl benzene) and aliphatic (e.g., n-hexane, dodecane). Succinate synthase enzymes, which belong to the glycyl radical enzyme family, are the main facilitators of these biochemical reactions. The overall catalytic mechanism that converts hydrocarbons to a succinate molecule involves three steps: (1) initial H-abstraction from the hydrocarbon by the radical enzyme, (2) addition of the resulting hydrocarbon radical to fumarate, and (3) hydrogen abstraction by the addition product to regenerate the radical enzyme. Since the biodegradation of hydrocarbon fuels via the fumarate addition mechanism is linked to bio-corrosion, an improved understanding of this reaction is imperative to our efforts of predicting the susceptibility of proposed alternative fuels to biodegradation. An improved understanding of the fuel biodegradation process also has the potential to benefit bioremediation. In this study, we consider model aromatic (toluene) and aliphatic (butane) compounds to evaluate the impact of hydrocarbon structure on the energetics and kinetics of the fumarate addition mechanism by means of high level ab initio gas-phase calculations. We predict that the rate of toluene degradation is ?100 times faster than butane at 298 K, and that the first abstraction step is kinetically significant for both hydrocarbons, which is consistent with deuterium isotope effect studies on toluene degradation. The detailed computations also show that the predicted stereo-chemical preference of the succinate products for both toluene and butane are due to the differences in the radical addition rate constants for the various isomers. The computational and kinetic modeling work presented here demonstrates the importance of considering pre-reaction and product complexes in order to accurately treat gas phase systems that involve intra and inter-molecular non-covalent interactions. PMID:25566585

  4. The impact of the weather conditions on the cooling performance of the heat pump driven by an internal natural gas combustion engine

    NASA Astrophysics Data System (ADS)

    Janovcová, Martina; Jandačka, Jozef; Malcho, Milan

    2015-05-01

    Market with sources of heat and cold offers unlimited choice of different power these devices, design technology, efficiency and price categories. New progressive technologies are constantly discovering, about which is still little information, which include heat pumps powered by a combustion engine running on natural gas. A few pieces of these installations are in Slovakia, but no studies about their work and effectiveness under real conditions. This article deals with experimental measurements of gas heat pump efficiency in cooling mode. Since the gas heat pump works only in system air - water, air is the primary low - energy source, it is necessary to monitor the impact of the climate conditions for the gas heat pump performance.

  5. Impact of 40 years poplar cultivation on soil carbon stocks and greenhouse gas fluxes

    NASA Astrophysics Data System (ADS)

    Ferré, C.; Leip, A.; Matteucci, G.; Previtali, F.; Seufert, G.

    2005-08-01

    Within the JRC Kyoto Experiment in the Regional Park and UN-Biosphere Reserve "Parco Ticino" (North-Italy, near Pavia), the soil carbon stocks and fluxes of CO2, N2O, and CH4 were measured in a poplar plantation in comparison with a natural mesohygrophilous deciduous forest nearby, which represents the pristine land cover of the area. Soil fluxes were measured using the static and dynamic closed chamber techniques for CH4 N2O, and CO2, respectively. We made further a pedological study to relate the spatial variability found with soil parameters.

    Annual emission fluxes of N2O and CO2 and deposition fluxes of CH4 were calculated for the year 2003 for the poplar plantation and compared to those measured at the natural forest site. N2O emissions at the poplar plantation were 0.15plusmn;0.1 g N2O m-2 y-1 and the difference to the emissions at the natural forest of 0.07±0.06 g N2O m-2 y-1 are partly due to a period of high emissions after the flooding of the site at the end of 2002. CH4 consumption at the natural forest was twice as large as at the poplar plantation. In comparison to the relict forest, carbon stocks in the soil under the poplar plantation were depleted by 61% of surface (10 cm) carbon and by 25% down the profile under tillage (45 cm). Soil respiration rates were not significant different at both sites with 1608±1053 and 2200±791 g CO2 m-2 y-1 at the poplar plantation and natural forest, respectively, indicating that soil organic carbon is much more stable in the natural forest. In terms of the greenhouse gas budget, the non-CO2 gases contributed minor to the overall soil balance with only 0.9% (N2O) and -0.3% (CH4 of CO2-eq emissions in the natural forest, and 2.7% (N2O) and -0.2% of CO2-eq. emissions in the poplar plantation.

    The very high spatial variability of soil fluxes within the two sites was related to the morphology of the floodplain area, which was formed by the historic course of the Ticino river and led to a small-scale (tenth of meters) variability in soil texture and to small-scale differences in elevation. Differences of site conditions are reflected by differences of inundation patterns, ecosystem productivity, CO2 and N2O emission rates, and soil contents of carbon and nitrogen. Additional variability was observed during a flooding event and after fertilisation at the poplar site. Despite of this variability, the two sites are comparable as both originate from alluvial deposits.

    The study shows that changes in soil carbon stocks and related fertility are the most visible phenomena after 40 years of land use change from a pristine forest to a fast growing poplar plantation. Therefore, the conservation and careful management of existing carbon stocks deserves highest priority in the context of the Kyoto Protocol.

  6. Assessing impacts of alternative fertilizer management practices on both nitrogen loading and greenhouse gas emissions in rice cultivation

    NASA Astrophysics Data System (ADS)

    Zhao, Zheng; Yue, Yubo; Sha, Zhimin; Li, Changsheng; Deng, Jia; Zhang, Hanlin; Gao, Maofang; Cao, Linkui

    2015-10-01

    Nitrogen (N) losses and greenhouse gas (GHG) emissions from paddy rice fields contaminate water bodies and atmospheric environment. A 2-year (2012-2013) field experiment was conducted at a typical paddy rice field in a rural suburb of Shanghai, China. N losses and GHG emissions from the paddy field with alternative fertilizer management practices were simultaneously measured. Four treatments were tested in the experiment: applications of only chemical synthetic fertilizer urea (CT), only organic manure (OT), a combination of the two types of fertilizers (MT) and a control (CK). Results from the field study indicated that CT produced the highest seasonal N loading rate (18.79 kg N/ha) and N2O emissions (1.81 kg N2O/ha) but with the lowest seasonal CH4 emissions (69.09 kg CH4/ha). With organic manure applied, MT and OT respectively reduced N loading by 21.86% and 30.41%, reduced N2O emissions by 28.34% and 69.41%, but increased CH4 emissions by 137% and 310% in comparison with CT. However, the net impact of CH4 and N2O emissions on global warming was enhanced when organic manure was applied. In addition, CT and MT produced the optimal rice yield during the experimental period, while OT treatment led to a yield reduction by 9.29% compared with CT. In conclusion, the impacts of alternative fertilizer management practices on ecosystem services ought to be assessed specifically due to the great variations across rice yields, N loss and GHG emissions.

  7. The Impact of Region, Nitrogen Use Efficiency, and Grower Incentives on Greenhouse Gas Mitigation in Canola (Brassica napus) Production

    NASA Astrophysics Data System (ADS)

    Hammac, W. A.; Pan, W.; Koenig, R. T.; McCracken, V.

    2012-12-01

    The Environmental Protection Agency (EPA) has mandated through the second renewable fuel standard (RFS2) that biodiesel meet a minimum threshold requirement (50% reduction) for greenhouse gas (GHG) emission reduction compared to fossil diesel. This designation is determined by life cycle assessment (LCA) and carries with it potential for monetary incentives for biodiesel feedstock growers (Biomass Crop Assistance Program) and biodiesel processors (Renewable Identification Numbers). A national LCA was carried out for canola (Brassica napus) biodiesel feedstock by the EPA and it did meet the minimum threshold requirement. However, EPA's national LCA does not provide insight into regional variation in GHG mitigation. The authors propose for full GHG reduction potential of biofuels to be realized, LCA results must have regional specificity and should inform incentives for growers and processors on a regional basis. The objectives of this work were to determine (1) variation in biofuel feedstock production related GHG emissions between three agroecological zones (AEZs) in eastern Washington State (2) the impact of nitrogen use efficiency (NUE) on GHG mitigation potential for each AEZ and (3) the impact of incentives on adoption of oilseed production. Results from objective (1) revealed there is wide variability in range for GHG estimates both across and within AEZs based on variation in farming practices and environment. It is expected that results for objective (2) will show further GHG mitigation potential due to minimizing N use and therefore fertilizer transport and soil related GHG emission while potentially increasing biodiesel production per hectare. Regional based incentives may allow more timely achievement of goals for bio-based fuels production. Additionally, incentives may further increase GHG offsetting by promoting nitrogen conserving best management practices implementation. This research highlights the need for regional assessment/incentive based strategies for maximizing GHG mitigation potential of biofuel feedstocks.

  8. Impacts of Enhanced-Efficiency Nitrogen Fertilizers on Greenhouse Gas Emissions in a Coastal Plain Soil under Cotton.

    PubMed

    Watts, Dexter B; Runion, G Brett; Smith Nannenga, Katy W; Torbert, H Allen

    2015-11-01

    Enhanced-efficiency N fertilizers (EENFs) have the potential to increase crop yield while decreasing soil N loss. However, the effect of EENFs on greenhouse gas (GHG) emissions from different agricultural systems is not well understood. Thus, studies from a variety of locations and cropping systems are needed to evaluate their impact. An experiment was initiated on a Coastal Plain soil under cotton ( L.) production for comparing EENFs to traditional sources. Nitrogen sources included urea, ammonia sulfate (AS), urea-ammonia sulfate (UAS), controlled-release, polymer-coated urea (Environmental Smart Nitrogen [ESN]), stabilized granular urea (SuperU), poultry litter (PL), poultry litter plus AgrotainPlus (PLA), and an unfertilized control. Carbon dioxide (CO), nitrous oxide (NO), and methane (CH) fluxes were monitored regularly after fertilization through harvest from 2009 to 2011 using a closed-chamber method. Poultry litter and PLA had higher CO flux than other N treatments, while ESN and SU were generally lowest following fertilization. Nitrous oxide fluxes were highly variable and rarely affected by N treatments; PL and PLA were higher but only during the few samplings in 2010 and 2011. Methane fluxes were higher in 2009 (wet year) than 2010 or 2011, and N treatments had minimal impact. Global warming potential (GWP), calculated from cumulative GHG fluxes, was highest with PL and PLA and lowest for control, UAS, ESN, and SU. Results suggest that PL application to cotton increases GHG flux, but GHG flux reductions from EENFs were infrequently different from standard inorganic fertilizers, suggesting their higher cost may render them presently impractical. PMID:26641321

  9. Impact of supplemental firing of tire-derived fuel (TDF) on mercury species and mercury capture with the advanced hybrid filter in a western subbituminous coal flue gas

    SciTech Connect

    Ye Zhuang; Stanley J. Miller

    2006-05-15

    Pilot-scale experimental studies were carried out to evaluate the impacts of cofiring tire-derived fuel and a western subbituminous coal on mercury species in flue gas. Mercury samples were collected at the inlet and outlet of the Advanced Hybrid filter to determine mercury concentrations in the flue gas with and without TDF cofiring, respectively. Cofiring of TDF with a subbituminous coal had a significant effect on mercury speciation in the flue gas. With 100% coal firing, there was only 16.8% oxidized mercury in the flue gas compared to 47.7% when 5% TDF (mass basis) was fired and 84.8% when 10% TDF was cofired. The significantly enhanced mercury oxidation may be the result of additional homogeneous gas reactions between Hg{sup 0} and the reactive chlorine generated in the TDF-cofiring flue gas and the in situ improved reactivity of unburned carbon in ash by the reactive chlorine species. Although the cofiring of TDF demonstrated limited improvement on mercury-emission control with the Advanced Hybrid filter, it proved to be a very cost-effective mercury control approach for power plants equipped with wet or dry flue gas desulfurization (FGD) systems because of the enhanced mercury oxidation. 15 refs., 4 figs., 4 tabs.

  10. Sulfur and Iron Speciation in Gas-rich Impact-melt Glasses from Basaltic Shergottites Determined by Microxanes

    NASA Technical Reports Server (NTRS)

    Sutton, S. R.; Rao, M. N.; Nyquist, L. E.

    2008-01-01

    Sulfur is abundantly present as sulfate near Martian surface based on chemical and mineralogical investigations on soils and rocks in Viking, Pathfinder and MER missions. Jarosite is identified by Mossbauer studies on rocks at Meridian and Gusev, whereas MgSO4 is deduced from MgO - SO3 correlations in Pathfinder MER and Viking soils. Other sulfate minerals such as gypsum and alunogen/ S-rich aluminosilicates and halides are detected only in martian meteorites such as shergottites and nakhlites using SEM/FE-SEM and EMPA techniques. Because sulfur has the capacity to occur in multiple valence states, determination of sulfur speciation (sulfide/ sulfate) in secondary mineral assemblages in soils and rocks near Mars surface may help us understand whether the fluid-rock interactions occurred under oxidizing or reducing conditions. To understand the implications of these observations for the formation of the Gas-rich Impact-melt (GRIM) glasses, we determined the oxidation state of Fe in the GRIM glasses using Fe K micro-XANES techniques.

  11. Fisheries impacts of underwater explosives used to salvage oil and gas platforms in the Gulf of Mexico

    SciTech Connect

    Gitschlag, G.R.

    1997-05-01

    There are more than 4,000 oil and gas structures present in the U.S. Gulf of Mexico. Approximately 100 structure removals occur each year and 66% of these are removed with explosives. From 1993-1995 an intensive study was conducted on the fish kill resulting from the explosive removal of 6 platforms off the Louisiana coast in water depths from 14-28 m (45-92 ft). After explosives were detonated, all floating fish and a sample of the dead fish which sank to the sea floor were collected. Estimated fish mortality ranged from approximately 2,000-5,000 with a mean of 3,000 and standard deviation of 1,045. The four most abundant species impacted by underwater explosives included spadefish, blue runner, red snapper, and sheepshead. One of these species, red snapper, is important both commercially and recreationally. Estimated mortality of red snapper ranged from 0-1200 with an average per platform of 500. A large standard deviation of 414 indicated high variability in red snapper mortality between platforms. Further study is planned to increase sample size, reduce variance, and address deeper water platform removals where red snapper abundance is expected to increase.

  12. Gas-phase reactive nitrogen near Grand Teton National Park: Impacts of transport, anthropogenic emissions, and biomass burning

    NASA Astrophysics Data System (ADS)

    Prenni, A. J.; Levin, E. J. T.; Benedict, K. B.; Sullivan, A. P.; Schurman, M. I.; Gebhart, K. A.; Day, D. E.; Carrico, C. M.; Malm, W. C.; Schichtel, B. A.; Collett, J. L.; Kreidenweis, S. M.

    2014-06-01

    Excess inputs of reactive nitrogen can adversely affect terrestrial and aquatic ecosystems, particularly in sensitive ecosystems found at high elevations. Grand Teton National Park is home to such sensitive natural areas and is in proximity to potentially large reactive nitrogen sources. The Grand Teton Reactive Nitrogen Deposition Study (GrandTReNDS) was conducted in spring-summer 2011, with the aim of better understanding sources of reactive nitrogen influencing the region, spatial and temporal variability of reactive nitrogen in the atmosphere, and current levels of nitrogen deposition. Overall, NOy was determined to be the most abundant class of ambient gas phase reactive nitrogen compounds, and ammonia was determined to be the most abundant individual nitrogen species. NOx, NOy and NH3 concentrations all showed a diel cycle, with maximum concentrations during the day and minimum concentrations at night. This pattern appeared to be driven, in part, by mountain-valley circulation as well as long range transport, which brought air to the site from anthropogenic sources in the Snake River Valley and northern Utah. In addition to the nitrogen sources noted above, we found elevated concentrations of all measured nitrogen species during periods impacted by biomass burning.

  13. Impact of the renewable oxygenate standard for reformulated gasoline on ethanol demand, energy use, and greenhouse gas emissions

    SciTech Connect

    Stork, K.C.; Singh, M.K.

    1995-04-01

    To assure a place for renewable oxygenates in the national reformulated gasoline (RFG) program, the US Environmental Protection Agency has promulgated the renewable oxygenate standard (ROS) for RFG. It is assumed that ethanol derived from corn will be the only broadly available renewable oxygenate during Phase I of the RFG program. This report analyzes the impact that the ROS could have on the supply of ethanol, its transported volume, and its displacement from existing markets. It also considers the energy and crude oil consumption and greenhouse gas (GHG) emissions that could result from the production and use of various RFGs that could meet the ROS requirements. The report concludes that on the basis of current and projected near-term ethanol capacity, if ethanol is the only available renewable oxygenate used to meet the requirements of the ROS, diversion of ethanol from existing use as a fuel is likely to be necessary. Year-round use of ethanol and ETBE would eliminate the need for diversion by reducing winter demand for ethanol. On an RFG-program-wide basis, using ethanol and ETBE to satisfy the ROS can be expected to slightly reduce fossil energy use, increase crude oil use, and have essentially no effect on GHG emissions or total energy use relative to using RFG oxygenated only with MTBE.

  14. Oil and gas impacts on air quality in federal lands in the Bakken region: an overview of the Bakken Air Quality Study and first results

    NASA Astrophysics Data System (ADS)

    Prenni, A. J.; Day, D. E.; Evanoski-Cole, A. R.; Sive, B. C.; Hecobian, A.; Zhou, Y.; Gebhart, K. A.; Hand, J. L.; Sullivan, A. P.; Li, Y.; Schurman, M. I.; Desyaterik, Y.; Malm, W. C.; Collett, J. L., Jr.; Schichtel, B. A.

    2016-02-01

    The Bakken formation contains billions of barrels of oil and gas trapped in rock and shale. Horizontal drilling and hydraulic fracturing methods have allowed for extraction of these resources, leading to exponential growth of oil production in the region over the past decade. Along with this development has come an increase in associated emissions to the atmosphere. Concern about potential impacts of these emissions on federal lands in the region prompted the National Park Service to sponsor the Bakken Air Quality Study over two winters in 2013-2014. Here we provide an overview of the study and present some initial results aimed at better understanding the impact of local oil and gas emissions on regional air quality. Data from the study, along with long-term monitoring data, suggest that while power plants are still an important emissions source in the region, emissions from oil and gas activities are impacting ambient concentrations of nitrogen oxides and black carbon and may dominate recent observed trends in pollutant concentrations at some of the study sites. Measurements of volatile organic compounds also definitively show that oil and gas emissions were present in almost every air mass sampled over a period of more than 4 months.

  15. Oil and gas impacts on air quality in federal lands in the Bakken region: an overview of the Bakken Air Quality Study and first results

    NASA Astrophysics Data System (ADS)

    Prenni, A. J.; Day, D. E.; Evanoski-Cole, A. R.; Sive, B. C.; Hecobian, A.; Zhou, Y.; Gebhart, K. A.; Hand, J. L.; Sullivan, A. P.; Li, Y.; Schurman, M. I.; Desyaterik, Y.; Malm, W. C.; Schichtel, B. A.; Collett, J. L., Jr.

    2015-10-01

    The Bakken formation contains billions of barrels of oil and gas trapped in rock and shale. Horizontal drilling and hydraulic fracturing methods have allowed for extraction of these resources, leading to exponential growth of oil production in the region over the past decade. Along with this development has come an increase in associated emissions to the atmosphere. Concern about potential impacts of these emissions on federal lands in the region prompted the National Park Service to sponsor the Bakken Air Quality Study over two winters in 2013-2014. Here we provide an overview of the study and present some initial results aimed at better understanding the impact of local oil and gas emissions on regional air quality. Data from the study, along with long term monitoring data, suggest that while power plants are still an important emissions source in the region, emissions from oil and gas activities are impacting ambient concentrations of nitrogen oxides and black carbon and may dominate recent observed trends in pollutant concentrations at some of the study sites. Measurements of volatile organic compounds also definitively show that oil and gas emissions were present in almost every air mass sampled over a period of more than four months.

  16. Impacts of Sedimentation from Oil and Gas Development on Stream Macroinvertebrates in Two Adjacent Watersheds of the Allegheny National Forest of Northwestern Pennsylvania

    SciTech Connect

    Fritz, K.; Harris, S.; Edenborn, H.M.; Sams, J.

    2011-01-01

    Fritz, Kelley'*, Steven Harris', Harry Edenborn2, and James Sams2. 'Clarion University of Pennsylvania, Clarion, PA 16214, 2National Energy Technology Laboratory, U.S. Dept. Energy, Pittsburgh, PA 15236. Impacts a/Sedimentation/rom Oil and Gas Development on Stream Macroinvertebrates in Two Adjacent Watersheds a/the Allegheny National Forest a/Northwestern Pennsylvania - The Allegheny National Forest (ANF), located in northwestern Pennsy Ivania, is a multiuse forest combining commercial development with recreational and conservation activities. As such, portions of the ANF have been heavily logged and are now the subject of widespread oil and gas development. This rapid increase in oil and gas development has led to concerns about sediment runoff from the dirt and gravel roads associated with development and the potential impact on the aquatic biota of the receiving streams. We examined and compared the benthic macroinvertebrate communities in two adjacent watersheds of similar size and topography in the ANF; the Hedgehog Run watershed has no oil and gas development, while the adjacent Grunder Run watershed has extensive oil and gas development. In Hedgehog and Grunder Run, we collected monthly kicknet samples from riffles and glides at two sites from April to October 2010. At the same intervals, we measured standard water quality parameters, including conductivity and turbidity. Preliminary results have indicated much higher turbidity in Grunder Run, but little difference in the diversity and abundance of benthic macro invertebrates inhabiting the two streams.

  17. Marcellus and mercury: Assessing potential impacts of unconventional natural gas extraction on aquatic ecosystems in northwestern Pennsylvania.

    PubMed

    Grant, Christopher J; Weimer, Alexander B; Marks, Nicole K; Perow, Elliott S; Oster, Jacob M; Brubaker, Kristen M; Trexler, Ryan V; Solomon, Caroline M; Lamendella, Regina

    2015-01-01

    Mercury (Hg) is a persistent element in the environment that has the ability to bioaccumulate and biomagnify up the food chain with potentially harmful effects on ecosystems and human health. Twenty-four streams remotely located in forested watersheds in northwestern PA containing naturally reproducing Salvelinus fontinalis (brook trout), were targeted to gain a better understanding of how Marcellus shale natural gas exploration may be impacting water quality, aquatic biodiversity, and Hg bioaccumulation in aquatic ecosystems. During the summer of 2012, stream water, stream bed sediments, aquatic mosses, macroinvertebrates, crayfish, brook trout, and microbial samples were collected. All streams either had experienced hydraulic fracturing (fracked, n = 14) or not yet experienced hydraulic fracturing (non-fracked, n = 10) within their watersheds at the time of sampling. Analysis of watershed characteristics (GIS) for fracked vs non-fracked sites showed no significant differences (P > 0.05), justifying comparisons between groups. Results showed significantly higher dissolved total mercury (FTHg) in stream water (P = 0.007), lower pH (P = 0.033), and higher dissolved organic matter (P = 0.001) at fracked sites. Total mercury (THg) concentrations in crayfish (P = 0.01), macroinvertebrates (P = 0.089), and predatory macroinvertebrates (P = 0.039) were observed to be higher for fracked sites. A number of positive correlations between amount of well pads within a watershed and THg in crayfish (r = 0.76, P < 0.001), THg in predatory macroinvertebrates (r = 0.71, P < 0.001), and THg in brook trout (r = 0.52, P < 0.01) were observed. Stream-water microbial communities within the Deltaproteobacteria also shared a positive correlation with FTHg and to the number of well pads, while stream pH (r = -0.71, P < 0.001), fish biodiversity (r = -0.60, P = 0.02), and macroinvertebrate taxa richness (r = -0.60, P = 0.01) were negatively correlated with the number of well pads within a watershed. Further investigation is needed to better elucidate relationships and pathways of observed differences in stream water chemistry, biodiversity, and Hg bioaccumulation, however, initial findings suggest Marcellus shale natural gas exploration is having an effect on aquatic ecosystems. PMID:25734824

  18. Results of the California Healthy Homes Indoor Air Quality Study of 2011-2013: impact of natural gas appliances on air pollutant concentrations.

    PubMed

    Mullen, N A; Li, J; Russell, M L; Spears, M; Less, B D; Singer, B C

    2016-04-01

    This study was conducted to assess the current impact of natural gas appliances on air quality in California homes. Data were collected via telephone interviews and measurements inside and outside of 352 homes. Passive samplers measured time-resolved CO and time-integrated NOX , NO2 , formaldehyde, and acetaldehyde over ~6-day periods in November 2011 - April 2012 and October 2012 - March 2013. The fraction of indoor NOX and NO2 attributable to indoor sources was estimated. NOX , NO2 , and highest 1-h CO were higher in homes that cooked with gas and increased with amount of gas cooking. NOX and NO2 were higher in homes with cooktop pilot burners, relative to gas cooking without pilots. Homes with a pilot burner on a floor or wall furnace had higher kitchen and bedroom NOX and NO2 compared to homes without a furnace pilot. When scaled to account for varying home size and mixing volume, indoor-attributed bedroom and kitchen NOX and kitchen NO2 were not higher in homes with wall or floor furnace pilot burners, although bedroom NO2 was higher. In homes that cooked 4 h or more with gas, self-reported use of kitchen exhaust was associated with lower NOX , NO2 , and highest 1-h CO. Gas appliances were not associated with higher concentrations of formaldehyde or acetaldehyde. PMID:25647016

  19. Anthropogenic Sulfur Perturbations on Biogenic Oxidation: SO2 Additions Impact Gas-Phase OH Oxidation Products of α- and β-Pinene.

    PubMed

    Friedman, Beth; Brophy, Patrick; Brune, William H; Farmer, Delphine K

    2016-02-01

    In order to probe how anthropogenic pollutants can impact the atmospheric oxidation of biogenic emissions, we investigated how sulfur dioxide (SO2) perturbations impact the oxidation of two monoterpenes, α-and β-pinene. We used chemical ionization mass spectrometry to examine changes in both individual molecules and gas-phase bulk properties of oxidation products as a function of SO2 addition. SO2 perturbations impacted the oxidation systems of α-and β-pinene, leading to an ensemble of products with a lesser degree of oxygenation than unperturbed systems. These changes may be due to shifts in the OH:HO2 ratio from SO2 oxidation and/or to SO3 reacting directly with organic molecules. Van Krevelen diagrams suggest a shift from gas-phase functionalization by alcohol/peroxide groups to functionalization by carboxylic acid or carbonyl groups, consistent with a decreased OH:HO2 ratio. Increasing relative humidity dampens the impact of the perturbation. This decrease in oxygenation may impact secondary organic aerosol formation in regions dominated by biogenic emissions with nearby SO2 sources. We observed sulfur-containing organic compounds following SO2 perturbations of monoterpene oxidation; whether these are the result of photochemistry or an instrumental artifact from ion-molecule clustering remains uncertain. However, our results demonstrate that the two monoterpene isomers produce unique suites of oxidation products. PMID:26735899

  20. Global Impacts of Gas-Phase Chemistry-Aerosol Interactions on Direct Radiative Forcing by Anthropogenic Aerosols and Ozone

    NASA Technical Reports Server (NTRS)

    Liao, Hong; Seinfeld, John H.

    2005-01-01

    We present here a first global modeling study on the influence of gas-phase chemistry/aerosol interactions on estimates of anthropogenic forcing by tropospheric O3 and aerosols. Concentrations of gas-phase species and sulfate, nitrate, ammonium, black carbon, primary organic carbon, secondary organic carbon, sea salt, and mineral dust aerosols in the preindustrial, present-day, and year 2100 (IPCC SRES A2) atmospheres are simulated online in the Goddard Institute for Space Studies general circulation model II' (GISS GCM II'). With fully coupled chemistry and aerosols, the preindustrial, presentday, and year 2100 global burdens of tropospheric ozone are predicted to be 190, 319, and 519 Tg, respectively. The burdens of sulfate, nitrate, black carbon, and organic carbon are predicted respectively to be 0.32. 0.18, 0.01, 0.33 Tg in preindustrial time, 1.40, 0.48, 0.23, 1.60 Tg in presentday, and 1.37, 1.97, 0.54, 3.31 Tg in year 2100. Anthropogenic O3 is predicted to have a globally and annually averaged present-day forcing of +0.22 W m(sup -2) and year 2100 forcing of +0.57 W m(sup -2) at the top of the atmosphere (TOA). Net anthropogenic TOA forcing by internally mixed sulfate, nitrate, organic carbon, and black carbon aerosols is estimated to be virtually zero in the present-day and +0.34 W m(sup -2) in year 2100, whereas it is predicted to be -0.39 W m(sup -2) in present-day and -0.61 W m(sup -2) in year 2100 if the aerosols are externally mixed. Heterogeneous reactions are shown to be important in affecting anthropogenic forcing. When reactions of N2O5, NO3, NO2, and HO2 on aerosols are accounted for, TOA anthropogenic O3 forcing is less by 20-45% in present-day and by 20-32% in year 2100 at mid to high latitudes in the Northern Hemisphere, as compared with values predicted in the absence of heterogeneous gas aerosol reactions. Mineral dust uptake of HNO3 and O3 is shown to have practically no influence on anthropogenic O3 forcing. Heterogeneous reactions of N2Os, NO3, NO2, and HO2 are predicted to have noticeable impacts on anthropogenic aerosol forcing over industrialized areas, leading to 0-2 W m(sup -2) more anthropogenic aerosol cooling in present-day and 2-8 W m(sup -2) more cooling in year 2100 in these areas as compared with forcings calculated in the absence of heterogeneous reactions. Sea salt uptake of SO2 reduces the magnitude of TOA aerosol cooling by 0.5-1 W m(sup -2) over the oceans around 60 N in the present-day and year 2100 scenarios. Near dust sources, mineral dust uptake of SO2 and HNO3 leads to less anthropogenic aerosol cooling by 0.5-1 W m(sup -2) in the present day and 1-2 W m(sup -2) in year 2100.

  1. A study of the gas-phase ozonolysis of terpenes: the impact of radicals formed during the reaction

    NASA Astrophysics Data System (ADS)

    Fick, Jerker; Pommer, Linda; Andersson, Barbro; Nilsson, Calle

    The gas-phase ozonolysis of α-pinene, Δ3-carene and limonene was investigated at ppb levels and the impact of the ozone, relative air humidity (RH), and time was studied using experimental design. The amounts of terpene reacted varied in the different settings and were as high as 8.1% for α-pinene, 10.9% for Δ3-carene and 23.4% for limonene. The designs were able to describe almost all the variation in the experimental data and were also successful in predicting omitted values. The results described the effects of time and ozone and also showed that RH did not have a statistically significant effect on the ozonolysis. The results also showed that all three terpenes were affected by an additional oxidation of OH radicals and/or other reactive species. The results from the designs states that this additional oxidation was responsible for 40% of the total amount of α-pinene reacted, 33% of the total amount of Δ3-carene reacted and 41% of the total amount of limonene reacted at the settings 20 ppb terpene, 75 ppb ozone, 20% RH and a reaction time of 213 s. Additional experiments with 2-butanol as OH radical scavenger showed that the reaction with OH radicals was responsible for 37% of the total α-pinene reacted and 39% of the total Δ3-carene reacted at the same settings. The scavenger experiments also showed that there were no significant amounts of OH radicals formed during the ozonolysis of limonene. The results from the designs were also compared to a mathematical model in order to evaluate further the data.

  2. Impact of the Asian monsoon on the extratropical lower stratosphere: trace gas observations during TACTS over Europe 2012

    NASA Astrophysics Data System (ADS)

    Müller, S.; Hoor, P.; Bozem, H.; Gute, E.; Vogel, B.; Zahn, A.; Bönisch, H.; Keber, T.; Krämer, M.; Rolf, C.; Riese, M.; Schlager, H.; Engel, A.

    2015-12-01

    The transport of air masses originating from the Asian monsoon anticyclone into the extratropical upper troposphere and lower stratosphere (Ex-UTLS) above potential temperatures Θ = 380 K was identified during the HALO aircraft mission TACTS in August and September 2012. In-situ measurements of CO, O3 and N2O during TACTS Flight 2 on the 30 August 2012 show the irreversible mixing of aged with younger (originating from the troposphere) stratospheric air masses within the Ex-UTLS. Backward trajectories calculated with the trajetory module of the CLaMS model indicate that these tropospherically affected air masses originate from the Asian monsoon anticyclone. From the monsoon circulation region these air masses are quasi-isentropically transported above Θ = 380 K into the Ex-UTLS where they subsequently mix with stratospheric air masses. The overall trace gas distribution measured during TACTS shows that this transport pathway has a significant impact on the Ex-UTLS during boreal summer and autumn. This leads to an intensification of the tropospheric influence on the Ex-UTLS with ΔΘ > 30 K (relative to the tropopause) within three weeks during the TACTS mission. In the same time period a weakening of the tropospheric influence on the lowermost stratosphere (LMS) is determined. Therefore, the study shows that the transport of air masses originating from the Asian summer monsoon region within the lower stratosphere above Θ = 380 K is of major importance for the change of the chemical composition of the Ex-UTLS from summer to autumn.

  3. Fluorine concentration in snow cover within the impact area of aluminium production plant (Krasnoyarsk city) and coal and gas-fired power plant (Tomsk city)

    NASA Astrophysics Data System (ADS)

    Talovskaya, A. V.; Osipova, N. A.; Filimonenko, E. A.; Polikanova, S. A.; Samokhina, N. P.; Yazikov, E. G.; Matveenko, I. A.

    2015-11-01

    The fluorine contents in snow melt water find in the impact areas of aluminum production plant and coal and gas-fired power plant are compared. In melt water, soluble fluoride is found in the form of fluoride ion, the content of which was determined by the potentiometric method using ion-selective electrode. According to the measurements of 2013-2014, fluoride content in melt water ranges 10.6-15.4 mg/dm3 at the distance 1-3 km from the borders of Krasnoyarsk aluminum plant with the mean value 13.1 mg/dm3. Four-year monitoring from 2012 to 2015 in the impact area of Tomsk coal and gas-fired power plant showed that fluoride content in melt water in vicinity of the thermal power plant is significantly lower than in the samples from the impact area of the aluminum plant. But higher content of fluoride ion (0.2 - 0.3 mg/dm3) in snow samples in vicinity of coal and gas-fired power plant was revealed in winter of 2015. Intake of soluble fluoride is mostly explained by dust-aerosol emissions of study plants and deposition of fluorine compounds from air.

  4. Impact of tetragonal rings on the stability of small fullerenes encapsulated with noble gas: A density functional theory survey

    NASA Astrophysics Data System (ADS)

    Wang, Wei-Wei; Dang, Jing-Shuang; Zhao, Xiang

    2012-05-01

    First-principles calculations have been applied to investigate low-lying C32 fullerenes and their noble gas endohedral complexes X@C32. We find that thermodynamic stabilities of related systems may change to the different extent when the noble gas is encaged, which reveals the selectivity of encapsulation for inert gas on different pristine fullerenes. A non-classical fullerene with D4d symmetry is predicted as the most stable structure and relative stabilities of its endohedral compounds enhance with the enlargement of inserted rare gas. The fragment including one square adjoined with four hexagons plays a substantial role on specific stabilities of corresponding complexes.

  5. Life cycle air emissions impacts and ownership costs of light-duty vehicles using natural gas as a primary energy source.

    PubMed

    Luk, Jason M; Saville, Bradley A; MacLean, Heather L

    2015-04-21

    This paper aims to comprehensively distinguish among the merits of different vehicles using a common primary energy source. In this study, we consider compressed natural gas (CNG) use directly in conventional vehicles (CV) and hybrid electric vehicles (HEV), and natural gas-derived electricity (NG-e) use in plug-in battery electric vehicles (BEV). This study evaluates the incremental life cycle air emissions (climate change and human health) impacts and life cycle ownership costs of non-plug-in (CV and HEV) and plug-in light-duty vehicles. Replacing a gasoline CV with a CNG CV, or a CNG CV with a CNG HEV, can provide life cycle air emissions impact benefits without increasing ownership costs; however, the NG-e BEV will likely increase costs (90% confidence interval: $1000 to $31 000 incremental cost per vehicle lifetime). Furthermore, eliminating HEV tailpipe emissions via plug-in vehicles has an insignificant incremental benefit, due to high uncertainties, with emissions cost benefits between -$1000 and $2000. Vehicle criteria air contaminants are a relatively minor contributor to life cycle air emissions impacts because of strict vehicle emissions standards. Therefore, policies should focus on adoption of plug-in vehicles in nonattainment regions, because CNG vehicles are likely more cost-effective at providing overall life cycle air emissions impact benefits. PMID:25825338

  6. Landowner Attitudes and Perceptions of Impact from Wind and Natural Gas Development in Northern Pennsylvania: Implications for Energy Landscapes in Rural America

    NASA Astrophysics Data System (ADS)

    Jacquet, Jeffrey Bryan

    Energy developments such as industrial scale wind farms and unconventional natural gas drilling represent some of the largest and most controversial land use changes occurring in the United States today. A diverse array of academic disciplines have each sought to explain the social, psychological, and economic effects of siting large industrial facilities in rural areas, however the research has largely remained discipline-specific. This study measures resident attitudes and perceptions of impact from both wind and gas drilling occurring simultaneously in the Armenia Mountain Area of northern Pennsylvania. The results of a mail survey of landowners (n = 1028) in this study area reveal factors that explain landowner variation in attitudes and perception of impact, and describe new forms of participation in the planning and siting of these energy projects. Direction is provided for a new and synthetic theoretical understanding of how residents perceive these impacts and impacts from land use change. The work advances risk of social and psychological disruption as a key factor that may influence how residents respond to the prospect of large land use changes. Implications for the regulation and planning of these energy sources are offered, including a new understanding of how landowners participate in the planning and siting of large energy projects. Finally, the limitations of this work, as well as opportunities and implications for future research, are discussed.

  7. Dissolved organic carbon (DOC) and select aldehydes in cloud and fog water: the role of the aqueous phase in impacting trace gas budgets

    NASA Astrophysics Data System (ADS)

    Ervens, B.; Wang, Y.; Eagar, J.; Leaitch, W. R.; Macdonald, A. M.; Valsaraj, K. T.; Herckes, P.

    2012-12-01

    Cloud and fog droplets efficiently scavenge and process water-soluble compounds and thus modify the chemical composition of the gas and particle phases. The concentrations of dissolved organic carbon (DOC) in the aqueous phase reach concentrations on the order of ~10 mg C L-1 which is typically on the same order of magnitude as the sum of inorganic anions. Aldehydes and carboxylic acids typically comprise a large fraction of DOC because of their high solubility. The dissolution of species in the aqueous phase can lead to (i) the removal of species from the gas phase preventing their processing by gas phase reactions (e.g. photolysis of aldehydes) and (ii) the formation of unique products that do not have any efficient gas phase sources (e.g. dicarboxylic acids). We present measurements of DOC and select aldehydes in fog water at high elevation and intercepted clouds in a biogenically-impacted location (Whistler, Canada) and in fog water in a more polluted area (Davis, CA). Concentrations of formaldehyde, glyoxal and methylglyoxal were in the micromolar range and comprised ?2% each individually of the DOC. Comparison of the DOC and aldehyde concentrations to those at other locations shows good agreement and reveals highest levels for both in anthropogenically impacted regions. Based on this overview, we conclude that the fraction of organic carbon (dissolved and insoluble inclusions) in the aqueous phase comprises 1-~40% of total organic carbon. Higher values are observed to be associated with aged air masses where organics are expected to be more highly oxidized and thus more soluble. Accordingly, the aqueous/gas partitioning ratio expressed here as an effective Henry's law constant for DOC (KH*DOC) increases by an order of magnitude from 7103 M atm-1 to 7104 M atm-1 during the ageing of air masses. The measurements are accompanied by photochemical box model simulations. They suggest that the scavenging of aldehydes by the aqueous phase can reduce HO2 gas phase levels by two orders of magnitude due to a weaker net source of HO2 production from aldehyde photolysis in the gas phase. Despite the high solubility of dialdehydes (glyoxal, methylglyoxal), their impact on the HO2 budget by scavenging is <10% of that of formaldehyde. The overview of DOC and aldehyde measurements presented here reveals that clouds and fogs can be efficient sinks for organics, with increasing importance in aged air masses. Even though aldehydes, specifically formaldehyde, only comprise ~1% of DOC, their scavenging and processing in the aqueous phase might translate into significant effects on the oxidation capacity of the atmosphere.

  8. 77 FR 2513 - Draft Environmental Impact Statement for Effects of Oil and Gas Activities in the Arctic Ocean

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-18

    ... Effects of Oil and Gas Activities in the Arctic Ocean AGENCY: National Marine Fisheries Service (NMFS... the Effects of Oil and Gas Activities in the Arctic Ocean.'' Based on several written requests... the Notice of Availability (76 FR 82275, December 30, 2011). Public Meetings Comments will be...

  9. 75 FR 67997 - Notice of Correction to Notice of Intent To Prepare an Environmental Impact Statement for the Gas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-04

    ... Uranium Project, Fremont and Natrona Counties, Wyoming (75 FR 54384). The notice inadvertently contained an incorrect legal land description. The correct legal land description for the Gas Hills Uranium... Statement for the Gas Hills Uranium Project, Fremont and Natrona Counties, WY AGENCY: Bureau of...

  10. Management practices impact on net global warming potential and greenhouse gas intensity from cropland soils – a review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural practices contribute significant amount of greenhouse gas (GHG) emissions, but little is known about their effects on net global warming potential (GWP) and greenhouse gas intensity (GHGI) that account for all sources and sinks of carbon dioxide emissions per unit area or crop yield. Se...

  11. 77 FR 47052 - El Paso Natural Gas Company; Notice of Intent To Prepare an Environmental Impact Statement for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-07

    ... Energy Regulatory Commission El Paso Natural Gas Company; Notice of Intent To Prepare an Environmental... (Project) involving construction and operation of facilities by El Paso Natural Gas Company (El Paso) in.... The Project would link El Paso's existing South Mainline System near Tucson to the U.S.-Mexico...

  12. Impact of arterial blood gas analysis in disability evaluation of the bituminous coal miner with simple pneumoconiosis.

    PubMed

    Fields, C L; Roy, T M; Dow, F T; Anderson, W H

    1992-04-01

    The Department of Labor has set guidelines for the use of resting arterial blood gas analysis in determination of total and permanent disability for coal workers' pneumoconiosis. To determine the prevalence with which bituminous coal miners fall below the arterial tensions of both oxygen and carbon dioxide published in the Federal Register, we studied 1012 miners who had both reproducible spirometry and arterial blood gas analysis as part of their disability evaluation. Eighty-seven percent of impaired miners could be identified by the spirometric criteria. Thirteen percent of impaired bituminous coal miners had acceptable pulmonary function but were eligible for black lung benefits by the blood gas guidelines. This population would have been missed if blood gas analysis were excluded from the evaluation process. On the other hand, approximately 25% of the blood gas analyses that were performed could be eliminated if a policy was adopted to do this test only on miners with spirometry that exceed the federal guidelines. PMID:1564579

  13. Evaluation of impact of shale gas operations in the Barnett Shale region on volatile organic compounds in air and potential human health risks.

    PubMed

    Bunch, A G; Perry, C S; Abraham, L; Wikoff, D S; Tachovsky, J A; Hixon, J G; Urban, J D; Harris, M A; Haws, L C

    2014-01-15

    Shale gas exploration and production (E&P) has experienced substantial growth across the U.S. over the last decade. The Barnett Shale, in north-central Texas, contains one of the largest, most active onshore gas fields in North America, stretching across 5000 square miles and having an estimated 15,870 producing wells as of 2011. Given that these operations may occur in relatively close proximity to populated/urban areas, concerns have been expressed about potential impacts on human health. In response to these concerns, the Texas Commission on Environmental Quality established an extensive air monitoring network in the region. This network provides a unique data set for evaluating the potential impact of shale gas E&P activities on human health. As such, the objective of this study was to evaluate community-wide exposures to volatile organic compounds (VOCs) in the Barnett Shale region. In this current study, more than 4.6 million data points (representing data from seven monitors at six locations, up to 105 VOCs/monitor, and periods of record dating back to 2000) were evaluated. Measured air concentrations were compared to federal and state health-based air comparison values (HBACVs) to assess potential acute and chronic health effects. None of the measured VOC concentrations exceeded applicable acute HBACVs. Only one chemical (1,2-dibromoethane) exceeded its applicable chronic HBACV, but it is not known to be associated with shale gas production activities. Annual average concentrations were also evaluated in deterministic and probabilistic risk assessments and all risks/hazards were below levels of concern. The analyses demonstrate that, for the extensive number of VOCs measured, shale gas production activities have not resulted in community-wide exposures to those VOCs at levels that would pose a health concern. With the high density of active wells in this region, these findings may be useful for understanding potential health risks in other shale play regions. PMID:24076504

  14. Influence of Biochar on C and N Transformation in Soil and Their Impact on Greenhouse Gas Emissions

    NASA Astrophysics Data System (ADS)

    Chintala, R.; Schumacher, T. E.; Kumar, S.; Clay, D. E.; Malo, D. D.

    2014-12-01

    The capacity of pyrogenic biochar to mitigate soil surface exchange of greenhouse gases (GHG) is dependent on the influence of biochar on physiochemical transformations of C and N in soils. Incorporated biochar amendments are hypothesized to interfere with transformations of C and N as a result of the unique recalcitrant chemical structure and surface complexity of biochars. The nature of interference by biochar with C and N transformations are assumed to be dynamic not only due to their highly variable amphilicity inherited from feedstock source and controlled pyrolytic processing parameters but also to variation in soil factors. Experiments comprised of laboratory and field studies were designed to gain insight into the priming effect of incorporated non-native biochar materials on the transformations of C and N species in the soil. Molecular structure and surface functionality of plant based biochar materials produced from carbon optimized gasification of corn stover (Zea mays L.), Ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue, and switchgrass (Panicum virgatum L.) were studied in the laboratory using NMR and SEM-EdX. Biochar materials were found to be highly hydrophobic (low H/C values) with high aromaticity. The surface morphology of all the biochar materials was highly heterogeneous and pore size ranged from 1-22µm with the faces and edges of ordered sheets. In the field study, all the three biochar types were applied at a 1% (w/w) rate to a Maddock soil (Sandy, Mixed, Frigid Entic Hapludolls) located in an eroded upper landscape position and a Brookings soil (Fine-Silty, Mixed, Superactive, Frigid Pachic Hapludolls) located in a depositional landscape position. The crop rotation is a corn (Zea mays L.) followed by soybean (Glycine max L.). The priming effect of biochars on the transformations of C and N is determined by measuring the changes in soil C (total organic carbon, microbial biomass C, hydrolyzable C, and δ 13C) and N pools (microbial biomass N, inorganic N, and δ 15N). Greenhouse gas fluxes (CO2, CH4, and N2O) were measured and correlation studies will be conducted to determine the relationship with the interference effect of biochars on C and N transformation in soil. Initial data shows that biochar has an impact especially on CO2, and N2O emissions.

  15. Numerical Simulation of Subsurface Transport and Groundwater Impacts from Hydraulic Fracturing of Tight/Shale Gas Reservoirs

    NASA Astrophysics Data System (ADS)

    Reagan, M. T.; Moridis, G. J.; Keen, N. D.

    2014-12-01

    The use of reservoir stimulation techniques, such as hydraulic fracturing, has grown tremendously over the last decade, and concerns have arisen that reservoir stimulation creates environmental threats through the creation of permeable pathways that could connect the stimulated reservoir to shallower groundwater aquifers. This study investigates, by numerical simulation, gas and water transport between a deeper tight-gas reservoir and a shallower overlying groundwater aquifer following hydraulic fracturing operations, assuming that the formation of a connecting pathway has already occurred. We focus on two general transport scenarios: 1) communication between the reservoir and aquifer via a connecting fracture or fault and 2) communication via a deteriorated, preexisting nearby well. The simulations explore a range of permeabilities and geometries over time scales, and evaluate the mechanisms and factors that could lead to the escape of gas or reservoir fluid and the contamination of groundwater resources. We also examine the effects of overpressured reservoirs, and explore long-term transport processes as part of a continuing study. We conclude that the key factors driving short-term transport of gas include high permeability for the connecting pathway and the overall volume of the connecting feature. Gas production from the reservoir via a horizontal well is likely to mitigate release through the reduction of available free gas and the lowering of reservoir pressure. We also find that fractured tight-gas reservoirs are unlikely to act as a continuing source of large volumes of migrating gas, and incidents of gas escape are likely to be limited in duration and scope. Reliable field and laboratory data must be acquired to constrain the factors and determine the likelihood of these outcomes.

  16. 78 FR 65637 - Sierrita Gas Pipeline LLC; Notice of Availability of the Draft Environmental Impact Statement for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-01

    ...-inch-diameter natural gas pipeline in Pima County, Arizona; two meter stations; two pig launchers and two pig receivers; \\1\\ and \\1\\ A pig is an internal tool that can be used to clean and dry a...

  17. The impact of ice layers on gas transport through firn at the North Greenland Eemian Ice Drilling (NEEM) site, Greenland

    NASA Astrophysics Data System (ADS)

    Keegan, K.; Albert, M. R.; Baker, I.

    2014-10-01

    Typically, gas transport through firn is modeled in the context of an idealized firn column. However, in natural firn, imperfections are present, which can alter transport dynamics and therefore reduce the accuracy of reconstructed climate records. For example, ice layers have been found in several firn cores collected in the polar regions. Here, we examined the effects of two ice layers found in a NEEM, Greenland firn core on gas transport through the firn. These ice layers were found to have permeability values of 3.0 and 4.0 10-10 m2, and are therefore not impermeable layers. However, the shallower ice layer was found to be significantly less permeable than the surrounding firn, and can therefore retard gas transport. Large closed bubbles were found in the deeper ice layer, which will have an altered gas composition than that expected because they were closed near the surface after the water phase was present. The bubbles in this layer represent 12% of the expected closed porosity of this firn layer after the firn-ice transition depth is reached, and will therefore bias the future ice core gas record. The permeability and thickness of the ice layers at the North Greenland Eemian Ice Drilling (NEEM) site suggest that they do not disrupt the firn-air concentration profiles and that they do not need to be accounted for in gas transport models at NEEM.

  18. Collision-energy-resolved metastable impact electron spectroscopy of thiophene and 2,2'-bithiophene: Stereodynamics in gas phase and adsorbed layer on Ag(110)

    NASA Astrophysics Data System (ADS)

    Kudo, S.; Kishimoto, N.; Ohno, K.

    2010-06-01

    2,2'-bithiophene in the gas phase was studied by ultraviolet photoelectron spectroscopy (UPS) and two-dimensional Penning ionization electron spectroscopy (2D-PIES) to obtain the information of stereodynamics in Penning ionization and anisotropic interaction around the ionization region. Thiophene and the 2,2'-bithiophene layer on a Ag(110) surface were investigated by two-dimensional metastable impact electron spectroscopy (2D-MIES). From the relative intensity in the UPS and PIES spectra and the collision energy dependence of partial ionization cross sections (CEDPICS) for 2,2'-bithiophene, ionization bands were assigned to π orbitals. A comparison with the CEDPICS for a gas molecule and the molecular layer on Ag(110) revealed that the attractive interaction between He*(23S) and both thiophene and 2,2-bithiophene was weak due to the formed molecular layer.

  19. Impact of gas chromatography and mass spectrometry combined with gas chromatography and olfactometry for the sex differentiation of Baccharis articulata by the analysis of volatile compounds.

    PubMed

    Minteguiaga, Manuel; Umpirrez, Noelia; Faria, Laura; Falco, Manuel A; Xavier, Vanessa B; Cassel, Eduardo; Dellacassa, Eduardo

    2015-09-01

    The Baccharis genus has more than 400 species of aromatic plants. However, only approximately 50 species have been studied in oil composition to date. From these studies, very few take into consideration differences between male and female plants, which is a significant and distinctive factor in Baccharis in the Asteraceae family. Baccharis articulata is a common shrub that grows wild in south Brazil, northern and central Argentina, Bolivia, Paraguay and Uruguay. It is considered to be a medicinal plant and is employed in traditional medicine. We report B. articulata male and female volatile composition obtained by simultaneous distillation-extraction technique and analyzed by gas chromatography with mass spectrometry. Also, an assessment of aromatic differences between volatile extracts was evaluated by gas chromatography with olfactometry. The results show a very similar chemical composition between male and female extracts, with a high proportion of terpene compounds of which ?-pinene, limonene and germacrene D are the main components. Despite the chemical similarity, great differences in aromatic profile were found: male plant samples exhibited the strongest odorants in number and intensity of aromatic attributes. These differences explain field observations which indicate differences between male and female flower aroma, and might be of ecological significance in the attraction of pollinating insects. PMID:26140379

  20. Comparative evaluation of the impacts of domestic gas and electric heat pump heating on air pollution in California. Final report

    SciTech Connect

    Ganji, A.

    1992-07-01

    Residential space and water heating accounts for approximately 12% of California`s and 15% of the United States, energy consumption. most Of the residential heating is by direct use of natural gas. combustion of natural gas is a contributor to the overall air pollution,, especially CO and NO{sub x} in the urban areas. Another efficient method for domestic water and space heating is use of electric heat pumps, the most popular category of which uses air as its heat source. Electric heat pumps do not emit air pollutants at the point of use, but use electric power, which is a major contributor to air pollution at its point of generation from fossil fuels. It is the specific objective of this report to evaluate and compare the energy efficiency and source air pollutants of natural gas heaters and electric heat pumps used for domestic heating. Effect of replacing natural gas heaters with electric heat pumps on air pollutant emissions due to domestic heating in two urban areas and in California as a whole has also been evaluated. The analysis shows that with the present state of technology, electric heat pumps have higher heating efficiencies than natural gas heaters. Considering the current electricity generation mix in the US, electric heat pumps produce two to four times more NO{sub x}, much less CO, and comparable amount of CO{sub 2} per unit of useful heating energy compared to natural gas heaters. With California mix, electric heat pumps produce comparable NO{sub x} and much less CO and approximately 30% less CO{sub 2} per unit heat output. Replacement of natural gas heaters with electric heat pumps will slightly increase the overall NO{sub x}, and reduce CO and CO{sub 2} emissions in California. The effect of advanced technology power generation and heat pump heating has also been analyzed.

  1. Comparative evaluation of the impacts of domestic gas and electric heat pump heating on air pollution in California

    SciTech Connect

    Ganji, A. . Div. of Engineering)

    1992-07-01

    Residential space and water heating accounts for approximately 12% of California's and 15% of the United States, energy consumption. most Of the residential heating is by direct use of natural gas. combustion of natural gas is a contributor to the overall air pollution,, especially CO and NO{sub x} in the urban areas. Another efficient method for domestic water and space heating is use of electric heat pumps, the most popular category of which uses air as its heat source. Electric heat pumps do not emit air pollutants at the point of use, but use electric power, which is a major contributor to air pollution at its point of generation from fossil fuels. It is the specific objective of this report to evaluate and compare the energy efficiency and source air pollutants of natural gas heaters and electric heat pumps used for domestic heating. Effect of replacing natural gas heaters with electric heat pumps on air pollutant emissions due to domestic heating in two urban areas and in California as a whole has also been evaluated. The analysis shows that with the present state of technology, electric heat pumps have higher heating efficiencies than natural gas heaters. Considering the current electricity generation mix in the US, electric heat pumps produce two to four times more NO{sub x}, much less CO, and comparable amount of CO{sub 2} per unit of useful heating energy compared to natural gas heaters. With California mix, electric heat pumps produce comparable NO{sub x} and much less CO and approximately 30% less CO{sub 2} per unit heat output. Replacement of natural gas heaters with electric heat pumps will slightly increase the overall NO{sub x}, and reduce CO and CO{sub 2} emissions in California. The effect of advanced technology power generation and heat pump heating has also been analyzed.

  2. Impact of hot fluid advection on hydrocarbon gas production and seepage in mud volcano sediments of thick Cenozoic deltas

    NASA Astrophysics Data System (ADS)

    Nuzzo, Marianne; Elvert, Marcus; Schmidt, Mark; Scholz, Florian; Reitz, Anja; Hinrichs, Kai-Uwe; Hensen, Christian

    2012-08-01

    Hydrocarbon seeps are ubiquitous at gas-prone Cenozoic deltas such as the Nile Deep Sea Fan (NDSF) On the contrary at the periphery, a lower but sustained CH4 flux is indicated by deeper sulphate-methane transition zones and the presence of 13C-depleted biomarkers of AOM, consistent with predominantly immature organic matter. Values of ?13C-CH4?-60VPDB and decreased concentrations of 13C-enriched C2+ are typical of mixed microbial CH4 and biodegraded thermogenic gas from Plio-Pleistocene reservoirs of the region. The maturity of gas condensate migrated from pre-Miocene sources into Miocene reservoirs of the Western NDSF is higher than that of the gas vented at the centre of NAMV, supporting the hypothesis that it is rather released from the degradation of oil in Neogene reservoirs. Combined with the finding of hot pore water and petroleum at the centre, our results suggest that clay mineral dehydration of Neogene sediments, which takes place posterior to reservoir filling, may contribute to intense gas generation at high sedimentation rate deltas.

  3. Impacts of individual fish movement patterns on estimates of mortality due to dissolved gas supersaturation in the Columbia River Basin.

    SciTech Connect

    Scheibe, Timothy D.; Richmond, Marshall C.; Fidler, Larry E.

    2002-12-31

    Spatial and temporal distributions of dissolved gases in the Columbia and Snake rivers vary due to many factors including river channel and dam geometries, operational decisions, and natural variations in flow rates. As a result, the dissolved gas exposure histories experienced by migrating juvenile salmonids can vary significantly among individual fish. A discrete, particle-based model of individual fish movements and dissolved gas exposure history has been developed and applied to examine the effects of such variability on estimates of fish mortality. The model, called the Fish Individual-based Numerical Simulator or FINS, is linked to a two-dimensional (vertically-averaged) hydrodynamic simulator that quantifies local water velocity, temperature, and dissolved gas levels as a function of river flow rates and dam operations. Simulated gas exposure histories are then input to biological mortality models to predict the effects of various river configurations on fish injury and mortality due to dissolved gas supersaturation. This model framework provides a critical linkage between hydrodynamic models of the river system and models of biological effects. FINS model parameters were estimated and validated based on observations of individual fish movements collected using radiotelemetry methods during 1997 and 1998. The model was then used to simulate exposure histories under selected operational scenarios. We compare mortality rates estimated using the FINS model approach (incorporating individual behavior and spatial and temporal variability) to those estimated using average exposure times and levels as is done in traditional lumped-parameter model approaches.

  4. The impact of plasma-wall interaction on the gas mixing efficiency in electron cyclotron resonance ion source

    SciTech Connect

    Schachter, L.; Dobrescu, S.; Stiebing, K. E.

    2012-02-15

    It is generally accepted that different effects are necessary to explain the gas mixing method of increasing the output of highly charged ions from an ECRIS. The two most important effects are the mass effect and the dilution effect. Their relative weights have not been determined experimentally yet, but it is generally assumed that the mass effect is dominant in standard ECRIS installations with stainless steel plasma chambers. In order to gain more insight into the physics of the gas mixing effect and in particular on the relevance of the dilution process, we have carried out a study where we have investigated the role of the plasma-wall interaction on the gas mixing effect. In this contribution, we shall discuss Charge state distributions spectra, measured at the Frankfurt ECRIS using different working gases, pure argon, a mixture of argon and oxygen, and argon mixed with neon.

  5. Regional air quality impacts of hydraulic fracturing and shale natural gas activity: Evidence from ambient VOC observations

    NASA Astrophysics Data System (ADS)

    Vinciguerra, Timothy; Yao, Simon; Dadzie, Joseph; Chittams, Alexa; Deskins, Thomas; Ehrman, Sheryl; Dickerson, Russell R.

    2015-06-01

    Over the past decade, concentrations of many anthropogenic pollutants have been successfully reduced, improving air quality. However, a new influx of emissions associated with hydraulic fracturing and shale natural gas operations could be counteracting some of these benefits. Using hourly measurements from Photochemical Assessment Monitoring Stations (PAMS) in the Baltimore, MD and Washington, DC areas, we observed that following a period of decline, daytime ethane concentrations have increased significantly since 2010, growing from ∼7% of total measured nonmethane organic carbon to ∼15% in 2013. This trend appears to be linked with the rapidly increasing natural gas production in upwind, neighboring states, especially Pennsylvania and West Virginia. Ethane concentrations failed to display this trend at a PAMS site outside of Atlanta, GA, a region without new widespread natural gas operations.

  6. Dissolved organic carbon (DOC) and select aldehydes in cloud and fog water: the role of the aqueous phase in impacting trace gas budgets

    NASA Astrophysics Data System (ADS)

    Ervens, B.; Wang, Y.; Eagar, J.; Leaitch, W. R.; Macdonald, A. M.; Valsaraj, K. T.; Herckes, P.

    2013-05-01

    Cloud and fog droplets efficiently scavenge and process water-soluble compounds and, thus, modify the chemical composition of the gas and particle phases. The concentrations of dissolved organic carbon (DOC) in the aqueous phase reach concentrations on the order of ~ 10 mgC L-1 which is typically on the same order of magnitude as the sum of inorganic anions. Aldehydes and carboxylic acids typically comprise a large fraction of DOC because of their high solubility. The dissolution of species in the aqueous phase can lead to (i) the removal of species from the gas phase preventing their processing by gas phase reactions (e.g., photolysis of aldehydes) and (ii) the formation of unique products that do not have any efficient gas phase sources (e.g., dicarboxylic acids). We present measurements of DOC and select aldehydes in fog water at high elevation and intercepted clouds at a biogenically-impacted location (Whistler, Canada) and in fog water in a more polluted area (Davis, CA). Concentrations of formaldehyde, glyoxal and methylglyoxal were in the micromolar range and comprised ? 2% each individually of the DOC. Comparison of the DOC and aldehyde concentrations to those at other locations shows good agreement and reveals highest levels for both in anthropogenically impacted regions. Based on this overview, we conclude that the fraction of organic carbon (dissolved and insoluble inclusions) in the aqueous phase of clouds or fogs, respectively, comprises 2-~ 40% of total organic carbon. Higher values are observed to be associated with aged air masses where organics are expected to be more highly oxidised and, thus, more soluble. Accordingly, the aqueous/gas partitioning ratio expressed here as an effective Henry's law constant for DOC (KH*DOC) increases by an order of magnitude from 7 103 M atm-1 to 7 104 M atm-1 during the ageing of air masses. The measurements are accompanied by photochemical box model simulations. These simulations are used to contrast two scenarios, i.e., an anthropogenically vs. a more biogenically impacted one as being representative for Davis and Whistler, respectively. Since the simplicity of the box model prevents a fully quantitative prediction of the observed aldehyde concentrations, we rather use the model results to compare trends in aldehyde partitioning and ratios. They suggest that the scavenging of aldehydes by the aqueous phase can reduce HO2 gas phase levels significantly by two orders of magnitude due to a weaker net source of HO2 production from aldehyde photolysis in the gas phase. Despite the high solubility of dicarbonyl compounds (glyoxal, methylglyoxal), their impact on the HO2 budget by scavenging is < 10% of that of formaldehyde. The overview of DOC and aldehyde measurements presented here reveals that clouds and fogs can be efficient sinks for organics, with increasing importance in aged air masses. Even though aldehydes, specifically formaldehyde, only comprise ~ 1% of DOC, their scavenging and processing in the aqueous phase might translate into significant effects in the oxidation capacity of the atmosphere.

  7. [Health and environmental licensing: a methodological proposal for assessment of the impact of the oil and gas industry].

    PubMed

    Barbosa, Eduardo Macedo; Barata, Matha Macedo de Lima; Hacon, Sandra de Souza

    2012-02-01

    Bearing in mind the importance of the impacts of the oil industry on human health, this article seeks to present a methodological proposal for analysis of these aspects in environmental impact assessment studies, based on the established legal parameters and a validated matrix for the hydroelectric sector. The lack of health considerations in the environmental impact assessment was detected in most of the 21 oil production enterprises analyzed, that were licensed in the period from January 1, 2004 through October 30, 2009. The health matrix proved to be an appropriate methodological approach to analyze these aspects in the environmental licensing process, guiding decisions and interventions in socio-environmental management. PMID:22267026

  8. Explicit Finite Element Modeling of Multilayer Composite Fabric for Gas Turbine Engine Containment Systems. Part 2; Ballistic Impact Testing

    NASA Technical Reports Server (NTRS)

    Pereira, J. M.; Revilock, D. M.

    2004-01-01

    Under the Federal Aviation Administration's Airworthiness Assurance Center of Excellence and the Aircraft Catastrophic Failure Prevention Program, National Aeronautics and Space Administration Glenn Research Center collaborated with Arizona State University, Honeywell Engines, Systems and Services, and SRI International to develop improved computational models for designing fabric-based engine containment systems. In the study described in this report, ballistic impact tests were conducted on layered dry fabric rings to provide impact response data for calibrating and verifying the improved numerical models. This report provides data on projectile velocity, impact and residual energy, and fabric deformation for a number of different test conditions.

  9. How Deep is the Critical Zone: A Scientific Question with Potential Impact For Decision-makers in Areas of Shale-Gas Development and Hydraulic Fracturing

    NASA Astrophysics Data System (ADS)

    Brantley, S. L.

    2014-12-01

    Citizens living in areas of shale-gas development such as the Marcellus gas play in Pennsylvania and surrounding states are cognizant of the possibility that drilling and production of natural gas -- including hydraulic fracturing -- may have environmental impacts on their water. The Critical Zone is defined as the zone from vegetation canopy to the lower limits of groundwater. This definition is nebulous in terms of the lower limit, and yet, defining the bottom of the Critical Zone is important if citizens are to embrace shale-gas development. This is because, although no peer-reviewed study has been presented that documents a case where hydraulic fracturing or formation fluids have migrated upwards from fracturing depths to drinking water resources, a few cases of such leakage have been alleged. On the other hand, many cases of methane migration into aquifers have been documented to occur and some have been attributed to shale-gas development. The Critical Zone science community has a role to play in understanding such contamination problems, how they unfold, and how they should be ameliorated. For example, one big effort of the Critical Zone science community is to promote sharing of data describing the environment. This data effort has been extended to provide data for citizens to understand water quality by a team known as the Shale Network. As scientists learn to publish data online, these efforts must also be made accessible to non-scientists. As citizens access the data, the demand for data will grow and all branches of government will eventually respond by providing more accessible data that will help the public and policy-makers make decisions.

  10. Enhanced Photoacoustic Gas Analyser Response Time and Impact on Accuracy at Fast Ventilation Rates during Multiple Breath Washout

    PubMed Central

    Horsley, Alex; Macleod, Kenneth; Gupta, Ruchi; Goddard, Nick; Bell, Nicholas

    2014-01-01

    Background The Innocor device contains a highly sensitive photoacoustic gas analyser that has been used to perform multiple breath washout (MBW) measurements using very low concentrations of the tracer gas SF6. Use in smaller subjects has been restricted by the requirement for a gas analyser response time of <100 ms, in order to ensure accurate estimation of lung volumes at rapid ventilation rates. Methods A series of previously reported and novel enhancements were made to the gas analyser to produce a clinically practical system with a reduced response time. An enhanced lung model system, capable of delivering highly accurate ventilation rates and volumes, was used to assess in vitro accuracy of functional residual capacity (FRC) volume calculation and the effects of flow and gas signal alignment on this. Results 1090% rise time was reduced from 154 to 88 ms. In an adult/child lung model, accuracy of volume calculation was ?0.9 to 2.9% for all measurements, including those with ventilation rate of 30/min and FRC of 0.5 L; for the un-enhanced system, accuracy deteriorated at higher ventilation rates and smaller FRC. In a separate smaller lung model (ventilation rate 60/min, FRC 250 ml, tidal volume 100 ml), mean accuracy of FRC measurement for the enhanced system was minus 0.95% (range ?3.8 to 2.0%). Error sensitivity to flow and gas signal alignment was increased by ventilation rate, smaller FRC and slower analyser response time. Conclusion The Innocor analyser can be enhanced to reliably generate highly accurate FRC measurements down at volumes as low as those simulating infant lung settings. Signal alignment is a critical factor. With these enhancements, the Innocor analyser exceeds key technical component recommendations for MBW apparatus. PMID:24892522

  11. CO2 utilization and storage in shale gas reservoirs: Experimental results and economic impacts

    SciTech Connect

    Schaef, Herbert T.; Davidson, Casie L.; Owen, Antionette Toni; Miller, Quin R. S.; Loring, John S.; Thompson, Christopher J.; Bacon, Diana H.; Glezakou, Vassiliki Alexandra; McGrail, B. Peter

    2014-12-31

    Natural gas is considered a cleaner and lower-emission fuel than coal, and its high abundance from advanced drilling techniques has positioned natural gas as a major alternative energy source for the U.S. However, each ton of CO2 emitted from any type of fossil fuel combustion will continue to increase global atmospheric concentrations. One unique approach to reducing anthropogenic CO2 emissions involves coupling CO2 based enhanced gas recovery (EGR) operations in depleted shale gas reservoirs with long-term CO2 storage operations. In this paper, we report unique findings about the interactions between important shale minerals and sorbing gases (CH4 and CO2) and associated economic consequences. Where enhanced condensation of CO2 followed by desorption on clay surface is observed under supercritical conditions, a linear sorption profile emerges for CH4. Volumetric changes to montmorillonites occur during exposure to CO2. Theory-based simulations identify interactions with interlayer cations as energetically favorable for CO2 intercalation. Thus, experimental evidence suggests CH4 does not occupy the interlayer and has only the propensity for surface adsorption. Mixed CH4:CO2 gas systems, where CH4 concentrations prevail, indicate preferential CO2 sorption as determined by in situ infrared spectroscopy and X-ray diffraction techniques. Collectively, these laboratory studies combined with a cost-based economic analysis provide a basis for identifying favorable CO2-EOR opportunities in previously fractured shale gas reservoirs approaching final stages of primary gas production. Moreover, utilization of site-specific laboratory measurements in reservoir simulators provides insight into optimum injection strategies for maximizing CH4/CO2 exchange rates to obtain peak natural gas production.

  12. Differential Treatment of Pregnancy in Employment: The Impact of "General Electric Co. v. Gilbert" and "Nashville Gas Co. v. Satty."

    ERIC Educational Resources Information Center

    Taylor, Ellen T.

    1978-01-01

    After discussing the facts and reasoning of the two cases (General Electric Co. vs Gilbert and Nashville Gas Co. vs Satty), the author argues that the decisions are largely the product of pregnancy stereotypes and that the Court's reasoning is flawed and should not be applied outside the context of pregnancy. Journal availability: see EA 511 481.

  13. Impacts of prior land use and increased corn acreage on life cycle assessment of net greenhouse gas flux

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the increased demand for corn ethanol, farmers are expected to plant the largest corn acreage in the United States since 1944. One of the main reasons for producing corn ethanol is the reduced greenhouse gas (GHG) emissions compared with gasoline. However, quantifying the offset of GHG emission...

  14. 77 FR 32626 - Transcontinental Gas Pipe Line Company, LLC; Notice of Intent To Prepare an Environmental Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-01

    ... of this notice. Currently, the NPS, U.S. Environmental Protection Agency (EPA), and U.S. Army Corps... fire hazards. Evacuation plans Alternatives: Assessment of existing systems, alternative system... Energy Regulatory Commission Transcontinental Gas Pipe Line Company, LLC; Notice of Intent To Prepare...

  15. Impact of localized gas injection on ICRF coupling and SOL parameters in JET-ILW H-mode plasmas

    NASA Astrophysics Data System (ADS)

    Lerche, E.; Goniche, M.; Jacquet, P.; Van Eester, D.; Bobkov, V.; Colas, L.; Czarnecka, A.; Brezinsek, S.; Brix, M.; Crombe, K.; Graham, M.; Groth, M.; Monakhov, I.; Mathurin, T.; Matthews, G.; Meneses, L.; Noble, C.; Petrzilka, V.; Rimini, F.; Shaw, A.

    2015-08-01

    Recent JET-ILW [1,2] experiments reiterated the importance of tuning the plasma fuelling in order to optimize ion cyclotron resonance frequency (ICRF) heating in high power H-mode discharges. By fuelling the plasma from gas injection modules (GIMs) located in the mid-plane and on the top of the machine instead of adopting the more standardly used divertor GIMs, a considerable increase of the ICRF antenna coupling resistances was achieved with moderate gas injection rates (<1.5 1022 e/s). This effect is explained by an increase of the scrape-off-layer density in front of the antennas when mid-plane and top fuelling is used. By distributing the gas injection to optimize the coupling of all ICRF antenna arrays simultaneously, a substantial increase in the ICRF power capability and reliability was attained. Although similar core/pedestal plasma properties were observed for the different injection cases, the experiments indicate that the RF-induced impurity sources are reduced when switching from divertor to main chamber gas injection.

  16. Impact of using high-density polyethylene geomembrane layer as landfill intermediate cover on landfill gas extraction.

    PubMed

    Chen, Zezhi; Gong, Huijuan; Zhang, Mengqun; Wu, Weili; Liu, Yu; Feng, Jin

    2011-05-01

    Clay is widely used as a traditional cover material for landfills. As clay becomes increasingly costly and scarce, and it also reduces the storage capacity of landfills, alternative materials with low hydraulic conductivity are employed. In developing countries such as China, landfill gas (LFG) is usually extracted for utilization during filling stage, therefore, the intermediate covering system is an important part in a landfill. In this study, a field test of LFG extraction was implemented under the condition of using high-density polyethylene (HDPE) geomembrane layer as the only intermediate cover on the landfill. Results showed that after welding the HDPE geomembranes together to form a whole airtight layer upon a larger area of landfill, the gas flow in the general pipe increased 25% comparing with the design that the HDPE geomembranes were not welded together, which means that the gas extraction ability improved. However as the heat isolation capacity of the HDPE geomembrane layer is low, the gas generation ability of a shallow landfill is likely to be weakened in cold weather. Although using HDPE geomembrane layer as intermediate cover is acceptable in practice, the management and maintenance of it needs to be investigated in order to guarantee its effective operation for a long term. PMID:21232931

  17. Biodegradation of gas-phase styrene using the fungus Sporothrix variecibatus: impact of pollutant load and transient operation.

    PubMed

    Rene, Eldon R; Veiga, María C; Kennes, Christian

    2010-03-01

    Biofiltration of gas-phase styrene was studied using a newly isolated fungus Sporothrix variecibatus, in a perlite biofilter, at inlet concentrations and gas-flow rates ranging from 0.13 to 14 g m(-3) and 0.075 to 0.34 m(3) h(-1), respectively, corresponding to empty bed residence times (EBRT) ranging between 91 and 20s. Styrene loading rates were varied between 50 and 845 g m(-3) h(-1)and a maximum elimination capacity of 336 g m(-3) h(-1) was attained with nearly 65% styrene removal. On the other hand, the critical inlet loads to achieve more than 90% removal were 301, 240 and 92 g m(-3) h(-1) for EBRT of 91, 40, and 20s, respectively. In order to test the stability and shock bearing capacity of the fungal biofilter, short-term tests were conducted by suddenly increasing the gas-phase styrene concentration, while maintaining the gas-flow rate constant. The response, a restoration in the removal performance to previous high values, after subjecting the biofilter to shock loads proves the resilient nature of the attached Sporothrix sp. and its suitability for biofiltration under non-steady state conditions. PMID:20149411

  18. Impact of gas/particle partitioning of semivolatile organic compounds on source apportionment with positive matrix factorization.

    PubMed

    Xie, Mingjie; Hannigan, Michael P; Barsanti, Kelley C

    2014-08-19

    To quantify and minimize the influence of gas/particle (G/P) partitioning on receptor-based source apportionment using particle-phase semivolatile organic compound (SVOC) data, positive matrix factorization (PMF) coupled with a bootstrap technique was applied to three data sets mainly composed of "measured-total" (measured particle- + gas-phase), "particle-only" (measured particle-phase) and "predicted-total" (measured particle-phase + predicted gas-phase) SVOCs to apportion carbonaceous aerosols. Particle- (PM2.5) and gas-phase SVOCs were collected using quartz fiber filters followed by PUF/XAD-4/PUF adsorbents and measured using gas chromatography-mass spectrometry (GC-MS). Concentrations of gas-phase SVOCs were also predicted from their particle-phase concentrations using absorptive partitioning theory. Five factors were resolved for each data set, and the factor profiles were generally consistent across the three PMF solutions. Using a previous source apportionment study at the same receptor site, those five factors were linked to summertime biogenic emissions (odd n-alkane factor), unburned fossil fuels (light SVOC factor), road dust and/or cooking (n-alkane factor), motor vehicle emissions (PAH factor), and lubricating oil combustion (sterane factor). The "measured-total" solution was least influenced by G/P partitioning and used as reference. Two out of the five factors (odd n-alkane and PAH factors) exhibited consistent contributions for "particle-only" vs "measured-total" and "predicted-total" vs "measured-total" solutions. Factor contributions of light SVOC and n-alkane factors were more consistent for "predicted-total" vs "measured-total" than "particle-only" vs "measured-total" solutions. The remaining factor (sterane factor) underestimated the contribution by around 50% from both "particle-only" and "predicted-total" solutions. The results of this study confirm that when measured gas-phase SVOCs are not available, "predicted-total" SVOCs should be used to decrease the influence of G/P partitioning on receptor-based source apportionment. PMID:25083820

  19. An integrated approach for the evaluation of technological hazard impacts on air quality: the case of the Val d'Agri oil/gas plant

    NASA Astrophysics Data System (ADS)

    Calvello, M.; Esposito, F.; Trippetta, S.

    2014-08-01

    The Val d'Agri area (southern Italy) hosts one of the biggest onshore European reservoir and the largest oil/gas pre-treatment plant, named Centro Olio Val d'Agri (COVA), located in a rural/anthropized context. Several hazards are associated with this plant. These are mainly represented by possible impacts of the COVA atmospheric emissions on the local air quality and human health. This work uses a novel approach based on the integration of air quality measurements from the regional monitoring network, additional experimental measurements (i.e. sub-micrometre particulate matter (PM1) and black carbon (BC)) and advanced statistical analyses to provide a preliminary evaluation of the Val d'Agri air quality state and give some indication of specific areas potentially affected by COVA hazards. Results show that the COVA plant emissions have a particular impact on the air quality of the area closest to it. In this area several pollutants specifically related to the COVA combustion processes (i.e. nitrogen oxides, benzene and toluene) show the highest concentration values and significant correlations. The proposed approach represents a first step in the assessment of the risks associated with oil/gas exploration and pre-treatment activities and a starting point for the development of effective and exportable air quality monitoring strategies.

  20. An integrated approach for the evaluation of technological hazard impacts on air quality: the case of the Val d'Agri oil/gas plant

    NASA Astrophysics Data System (ADS)

    Calvello, M.; Esposito, F.; Trippetta, S.

    2014-04-01

    The Val d'Agri area (southern Italy) hosts the biggest on-shore European reservoir and the largest oil/gas pre-treatment plant, named Centro Olio Val d'Agri (COVA), located in a rural/anthropized context. Several hazards are associated to this plant. These are mainly represented by possible impacts of the COVA atmospheric emissions on the local air quality and human health. This work uses a novel approach based on the integration of air quality measurements from the regional monitoring network, additional experimental measurements (i.e., sub-micrometric particulate matter - PM1 and Black Carbon - BC) and advanced statistical analyses to provide a preliminary evaluation of the Val d'Agri air quality state and give some indications of specific areas potentially affected by COVA hazards. Results show that the COVA plant emissions exert an impact especially on the air quality of the area closest to it. In this area several pollutants specifically related to the COVA combustion processes (i.e., nitrogen oxides, benzene and toluene) show the highest concentration values and significant correlations. The proposed approach represents a first step in the assessment of the risks associated to oil/gas exploration and pre-treatment activities and a starting point for the development of effective and exportable air quality monitoring strategies.

  1. Golden age of gas and its impact on the world energy, the global carbon cycle and climate

    NASA Astrophysics Data System (ADS)

    Tereshin, A. G.; Klimenko, A. V.; Klimenko, V. V.

    2015-05-01

    Global and regional resource and environmental problems of production and use of unconventional gas (UG) are studied. Estimations for world and national reserves of various kinds of UG are presented. The dynamics of the gas share in total energy consumption and thermal power generation around the world is analyzed. Projections of the world production of conventional gas and UG are proposed. Variations in carbon dioxide concentration in the atmosphere and the corresponding changes in average global air temperature are calculated for various scenarios suggesting unconventional gas substitution of different energy sources. The possible consequences of expected climate changes for Russia's power industry are analyzed. It is shown that, despite the uncertainty in the estimates of the economic and environmental consequences of shale gas (SG) production, its use, according to the available resource estimates, can make it possible to solve global and regional problems associated with energy (import substitution) and environment protection (replacing the less clean coal fuel). However, the development of the huge global resources of this type of fuel can have a significant effect on the chemical and thermal radiative balance of the Earth's atmosphere, and it must be noted that the climatic effect of carbon dioxide emissions from the UG combustion greatly exceeds the consequences of methane leakage during its production. In order to sustain the stability of the global climate system, the development of the world's large UG resources must be accompanied by an equivalent reduction in the use of coal. This is the only way for UG to become a safe energy bridge to the future, able to keep the climate system at the threshold of critical values. Direct effects of possible climatic changes on the territory of Russia for the domestic energy complex are estimated as more positive than adverse, mainly due to lower energy costs for space heating.

  2. Volumetric strain associated with methane desorption and its impact on coalbed gas production from deep coal seams

    SciTech Connect

    Cui, X.J.; Bustin, R.M.

    2005-09-01

    For deep coal seams, significant reservoir pressure drawdown is required to promote gas desorption because of the Langmuir-type isotherm that typifies coals. Hence, a large permeability decline may occur because of pressure drawdown and the resulting increase in effective stress, depending on coal properties and the stress field during production. However, the permeability decline can potentially be offset by the permeability enhancement caused by the matrix shrinkage associated with methane desorption. The predictability of varying permeability is critical for coalbed gas exploration and production-well management. We have investigated quantitatively the effects of reservoir pressure and sorption-induced volumetric strain on coal-seam permeability with constraints from the adsorption isotherm and associated volumetric strain measured on a Cretaceous Mesaverde Group coal (Piceance basin) and derived a stress-dependent permeability model. Our results suggest that the favorable coal properties that can result in less permeability reduction during earlier production and an earlier strong permeability rebound (increase in permeability caused by coal shrinkage) with methane desorption include (1) large bulk or Young's modulus; (2) large adsorption or Langmuir volume; (3) high Langmuir pressure; (4) high initial permeability and dense cleat spacing; and (5) low initial reservoir pressure and high in-situ gas content. Permeability variation with gas production is further dependent on the orientation of the coal seam, the reservoir stress field, and the cleat structure. Well completion with injection of N2 and displacement of CH{sub 4} only results in short-term enhancement of permeability and does not promote the overall gas production for the coal studied.

  3. Impacts of Increased Access to Oil & Natural Gas Resources in the Lower 48 Federal Outer Continental Shelf (released in AEO2007)

    EIA Publications

    2007-01-01

    This analysis was updated for Annual Energy Outlook 2009 (AEO): Impact of Limitations on Access to Oil and Natural Gas Resources in the Federal Outer Continental Shelf (OCS). The OCS is estimated to contain substantial resources of crude oil and natural gas; however, some areas of the OCS are subject to drilling restrictions. With energy prices rising over the past several years, there has been increased interest in the development of more domestic oil and natural gas supply, including OCS resources. In the past, federal efforts to encourage exploration and development activities in the deep waters of the OCS have been limited primarily to regulations that would reduce royalty payments by lease holders. More recently, the states of Alaska and Virginia have asked the federal government to consider leasing in areas off their coastlines that are off limits as a result of actions by the President or Congress. In response, the Minerals Management Service (MMS) of the U.S. Department of the Interior has included in its proposed 5-year leasing plan for 2007-2012 sales of one lease in the Mid-Atlantic area off the coastline of Virginia and two leases in the North Aleutian Basin area of Alaska. Development in both areas still would require lifting of the current ban on drilling.

  4. Analysis of Restricted Natural Gas Supply Cases

    EIA Publications

    2004-01-01

    The four cases examined in this study have progressively greater impacts on overall natural gas consumption, prices, and supply. Compared to the Annual Energy Outlook 2004 reference case, the no Alaska pipeline case has the least impact; the low liquefied natural gas case has more impact; the low unconventional gas recovery case has even more impact; and the combined case has the most impact.

  5. Impacts of European livestock production: nitrogen, sulphur, phosphorus and greenhouse gas emissions, land-use, water eutrophication and biodiversity

    NASA Astrophysics Data System (ADS)

    Leip, Adrian; Billen, Gilles; Garnier, Josette; Grizzetti, Bruna; Lassaletta, Luis; Reis, Stefan; Simpson, David; Sutton, Mark A.; de Vries, Wim; Weiss, Franz; Westhoek, Henk

    2015-11-01

    Livestock production systems currently occupy around 28% of the land surface of the European Union (equivalent to 65% of the agricultural land). In conjunction with other human activities, livestock production systems affect water, air and soil quality, global climate and biodiversity, altering the biogeochemical cycles of nitrogen, phosphorus and carbon. Here, we quantify the contribution of European livestock production to these major impacts. For each environmental effect, the contribution of livestock is expressed as shares of the emitted compounds and land used, as compared to the whole agricultural sector. The results show that the livestock sector contributes significantly to agricultural environmental impacts. This contribution is 78% for terrestrial biodiversity loss, 80% for soil acidification and air pollution (ammonia and nitrogen oxides emissions), 81% for global warming, and 73% for water pollution (both N and P). The agriculture sector itself is one of the major contributors to these environmental impacts, ranging between 12% for global warming and 59% for N water quality impact. Significant progress in mitigating these environmental impacts in Europe will only be possible through a combination of technological measures reducing livestock emissions, improved food choices and reduced food waste of European citizens.

  6. The variation in molecular gas depletion time among nearby galaxies - II. The impact of galaxy internal structures

    NASA Astrophysics Data System (ADS)

    Huang, Mei-Ling; Kauffmann, Guinevere

    2015-06-01

    We use a data set of nearby galaxies drawn from the HERA CO-Line Extragalactic Survey, ATLAS3D, and COLD GASS surveys to study variations in molecular gas depletion time (tdep) in galaxy structures such as bulges, grand-design spiral arms, bars and rings. Molecular gas is traced by CO line emission and star formation rate (SFR) is derived using the combination of far-ultraviolet and mid-infrared (MIR) data. The contribution of old stars to MIR emission for the ATLAS3D sample is corrected using 2MASS K-band images. We apply a two-dimensional image decomposition algorithm to decompose galaxies into bulges and discs. Spiral arms, bars and rings are identified in the residual maps, and molecular gas depletion times are derived on a square grid of 1 kpc2 size. In previous work, we showed that tdep correlates strongly with specific star formation rate (sSFR). We now find that at a given sSFR, the bulge has shorter tdep than the disc. The shift to shorter depletion times is most pronounced in the inner bulge (R < 0.1 Re). Grids from galaxies with bars and rings are similar to those from galactic bulges in that they have reduced tdep at a given sSFR. In contrast, the tdep versus sSFR relation in the discs of galaxies with spiral arms is displaced to longer tdep at fixed sSFR. We then show that the differences in the tdep-sSFR relation for bulges, discs, arms, bars and rings can be linked to variations in stellar, rather than gas surface density between different structures. Our best current predictor for tdep, both globally and for 1 kpc grids, is given by tdep = -0.36 log (?SFR) - 0.50 log (?*) + 5.87.

  7. Potential for a solids fire during an ITP waste tank deflagration and the impact on gas pressure

    SciTech Connect

    Thomas, J.K.

    1993-07-01

    During the In-Tank Precipitation (ITP) process, solid deposits may form at the water-line on internal waste tank surfaces. These solids may be combustible due to the presence of tetraphenylborate compounds and hence there is a potential that a waste tank deflagration could ignite a solids fire. The work described in this report evaluates the potential for a waste tank deflagration to ignite a solids fire and the subsequent effect on gas pressure. Thermal analyses were performed using a one-dimensional conduction model, radiative heat flux values calculated with the Deflagration Pressure Analysis Code (DPAC), and effective deposit properties calculated from the component properties. It was shown that a solids fire could only be ignited by a waste tank deflagration for a limited range of cases. For the best-estimate mixtures, a solids fire could not be ignited prior to the time the peak gas pressure is reached and would not increase the peak pressure. For the upper-bound mixtures, the thickness of the solid layer which could be ignited is insufficient to increase the energy released by the deflagration by a significant amount. It was also shown that these conclusions are relatively insensitive to uncertainties related to deposit composition. Thus, the contribution from a solids fire to the gas pressure resulting from a waste tank deflagration may be neglected.

  8. LARGE-SCALE SHOCK-IONIZED AND PHOTOIONIZED GAS IN M83: THE IMPACT OF STAR FORMATION

    SciTech Connect

    Hong, Sungryong; Calzetti, Daniela; Dopita, Michael A.; Blair, William P.; Whitmore, Bradley C.; Bond, Howard E.; Balick, Bruce; Carollo, Marcella; Disney, Michael J.; Frogel, Jay A.; Hall, Donald; Holtzman, Jon A.; Kimble, Randy A.; McCarthy, Patrick J.; O'Connell, Robert W.; Paresce, Francesco; Saha, Abhijit; Silk, Joseph I.; Trauger, John T.; Walker, Alistair R.

    2011-04-10

    We investigate the ionization structure of the nebular gas in M83 using the line diagnostic diagram, [O III](5007 A)/H{beta} versus [S II](6716 A+6731 A)/H{alpha}, with the newly available narrowband images from the Wide Field Camera 3 (WFC3) of the Hubble Space Telescope (HST). We produce the diagnostic diagram on a pixel-by-pixel (0.''2 x 0.''2) basis and compare it with several photo- and shock-ionization models. We select four regions from the center to the outer spiral arm and compare them in the diagnostic diagram. For the photoionized gas, we observe a gradual increase of the log ([O III]/H{beta}) ratios from the center to the spiral arm, consistent with the metallicity gradient, as the H II regions go from super-solar abundance to roughly solar abundance from the center out. Using the diagnostic diagram, we separate the photoionized from the shock-ionized component of the gas. We find that the shock-ionized H{alpha} emission ranges from {approx}2% to about 15%-33% of the total, depending on the separation criteria used. An interesting feature in the diagnostic diagram is a horizontal distribution around log ([O III]/H{beta}) {approx} 0. This feature is well fit by a shock-ionization model with 2.0 Z{sub sun} metallicity and shock velocities in the range of 250-350 km s{sup -1}. A low-velocity shock component, <200 km s{sup -1}, is also detected and is spatially located at the boundary between the outer ring and the spiral arm. The low-velocity shock component can be due to (1) supernova remnants located nearby, (2) dynamical interaction between the outer ring and the spiral arm, and (3) abnormal line ratios from extreme local dust extinction. The current data do not enable us to distinguish among those three possible interpretations. Our main conclusion is that, even at the HST resolution, the shocked gas represents a small fraction of the total ionized gas emission at less than 33% of the total. However, it accounts for virtually all of the mechanical energy produced by the central starburst in M83.

  9. 75 FR 6175 - Notice of Intent to Prepare an Environmental Impact Statement on the Effects of Oil and Gas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-08

    ... (DPEIS) and a schedule of public hearings (72 FR 17117) to assess the impacts of MMS' issuance of permits.... Therefore, MMS and NMFS filed a Notice of Withdrawal of the DPEIS on October 28, 2009 (74 FR 55539) and... exploration and development wells, maximizing extraction and production from a reservoir, and to...

  10. Impact of Reduced Tillage and Cover Cropping on the Greenhouse Gas Budget of a Maize/Soybean Rotation Ecosystem

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to evaluate the impact of an alternative management scenario (reduced tillage and cover cropping) on ecosystem respiration and N2O and CH4 exchange in a maize (Zea mays L)/soybean (Glycine max L.) rotation agroecosystem in north-central Minnesota. The control treatmen...

  11. MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM - PRELIMINARY REPORT

    SciTech Connect

    Zamecnik, J.; Choi, A.

    2009-03-25

    The Defense Waste Processing Facility (DWPF) is currently evaluating an alternative Chemical Process Cell (CPC) flowsheet to increase throughput. It includes removal of the steam-stripping step, which would significantly reduce the CPC processing time and lessen the sampling needs. However, its downside would be to send 100% of the mercury that come in with the sludge straight to the melter. For example, the new mercury content in the Sludge Batch 5 (SB5) melter feed is projected to be 25 times higher than that in the SB4 with nominal steam stripping of mercury. This task was initiated to study the impact of the worst-case scenario of zero-mercury-removal in the CPC on the DWPF melter off-gas system. It is stressed that this study is intended to be scoping in nature, so the results presented in this report are preliminary. In order to study the impact of elevated mercury levels in the feed, it is necessary to be able to predict how mercury would speciate in the melter exhaust under varying melter operating conditions. A homogeneous gas-phase oxidation model of mercury by chloride was developed to do just that. The model contains two critical parameters pertaining to the partitioning of chloride among HCl, Cl, Cl{sub 2}, and chloride salts in the melter vapor space. The values for these parameters were determined at two different melter vapor space temperatures by matching the calculated molar ratio of HgCl (or Hg{sub 2}Cl{sub 2}) to HgCl{sub 2} with those measured during the Experimental-Scale Ceramic Melter (ESCM) tests run at the Pacific Northwest National Laboratory (PNNL). The calibrated model was then applied to the SB5 simulant used in the earlier flowsheet study with an assumed mercury stripping efficiency of zero; the molar ratio of Cl-to-Hg in the resulting melter feed was only 0.4, compared to 12 for the ESCM feeds. The results of the model run at the indicated melter vapor space temperature of 650 C (TI4085D) showed that due to excessive shortage of chloride, only 6% of the mercury fed is expected to get oxidized, mostly as HgCl, while the remaining mercury would exist either as elemental mercury vapor (90%) or HgO (4%). Noting that the measured chloride level in the SB5 qualification sample was an order of magnitude lower than that used in the SB5 simulant, the degree of chloride shortage will be even greater. As a result, the projected level of HgCl in the actual SB5 melter exhaust will be even lower than 6% of the total mercury fed, while that of elemental mercury is likely to be greater than 90%. The homogeneous oxidation of mercury in the off-gas was deemed to be of primary importance based on the postulation that mercury and other volatile salts form submicron sized aerosols upon condensation and thus remain largely in the gas stream downstream of the quencher where they can deposit in the off-gas lines, Steam-Atomized Scrubbers (SAS), and High-Efficiency Mist Eliminator (HEME). Formation of these submicron semi-volatile salts in the condensate liquid is considered to be unlikely, so the liquid phase reactions were considered to be less important. However, subsequent oxidation of mercury in the liquid phase in the off-gas system was examined in a simplified model of the off-gas condensate. It was found that the condensate chemistry was consistent with further oxidation of elemental mercury to Hg{sub 2}Cl{sub 2} and conversion of HgO to chlorides. The results were consistent with the available experimental data. It should also be noted that the model predictions presented in this report do not include any physically entrained solids, which typically account for much of the off-gas carryover on a mass basis. The high elemental mercury vapor content predicted at the DWPF Quencher inlet means that physically entrained solids could provide the necessary surface onto which elemental mercury vapor could condense, thereby coating the solids as well as the internal surfaces of the off-gas system with mercury. Clearly, there are many process benefits to be gained by removing the steam-stripping step from the CPC cycle. The goal of this task was to study what adverse impact the zero-mercury-removal scenario would have on the DWPF melter off-gas system operation. It is stressed again that this study was intended to be scoping in nature, so the results presented in this report are preliminary. Any further substantiation of these results for actual implementation into the DWPF flowsheet would require an in-depth modeling study of all three reaction zones, including the aqueous-phase reactions in the quencher, OGCT, Steam Atomized Scrubber (SAS), and off-gas condenser with recirculated condensate, and the proof-of-principle experiments.

  12. Collision-induced electronic excitation of CH+ ions by impact on rare gas atoms and some diatomic molecules

    NASA Astrophysics Data System (ADS)

    Ehbrecht, A.; Kowalski, A.; Ottinger, Ch

    1996-11-01

    Efficient excitation of the A1[Pi] and B1[Delta] electronic states of CH+ ions was observed in collisions of CH+(X1+) with noble gas atoms or diatomics (H2, D2, N2, O2, NO, CO) at kinetic energies up to 1 keVlab. This process and the competing charge transfer forming CH(A2[Delta]) were investigated by spectral analysis of the subsequent optical emission. In the energy range available, the excitation functions increase steadily with the collision energy. For systems where charge transfer excitation is negligible, the cross-section depends only moderately on the target gas species. Population of the CH+(B) state, which requires simultaneous excitation of two electrons in the collision, proceeds with unexpectedly high efficiency. The energy dependence here is somewhat different for rare gases and for diatomics. The total cross-sections for collisional formation of the electronically excited A and B states of CH+ are of the order of several Å2. From the ground singlet state only radiating singlet states of CH+ are collisionally populated, even when target gases are used for which the spin-conservation rule would permit population of the CH+(b3-) state; the collisional transfer to this state does, however, occur from the CH+(a3[Pi]) metastable state present in the projectile ion beam. The population of rotational states of CH+(A) corresponds to temperatures of 4000 K at 100 eVlab and 3000 K at 1000 eVlab, independent of the target gas.

  13. The impact of wet flue gas desulfurization scrubbing on mercury emissions from coal-fired power stations.

    PubMed

    Niksa, Stephen; Fujiwara, Naoki

    2005-07-01

    This article introduces a predictive capability for Hg retention in any Ca-based wet flue gas desulfurization (FGD) scrubber, given mercury (Hg) speciation at the FGD inlet, the flue gas composition, and the sulphur dioxide (SO2) capture efficiency. A preliminary statistical analysis of data from 17 full-scale wet FGDs connects flue gas compositions, the extents of Hg oxidation at FGD inlets, and Hg retention efficiencies. These connections clearly signal that solution chemistry within the FGD determines Hg retention. A more thorough analysis based on thermochemical equilibrium yields highly accurate predictions for total Hg retention with no parameter adjustments. For the most reliable data, the predictions were within measurement uncertainties for both limestone and Mg/lime systems operating in both forced and natural oxidation mode. With the U.S. Environmental Protection Agency's (EPA) Information Collection Request (ICR) database, the quantitative performance was almost as good for the most modern FGDs, which probably conform to the very high SO2 absorption efficiencies assumed in the calculations. The large discrepancies for older FGDs are tentatively attributed to the unspecified SO2 capture efficiencies and operating temperatures and to the possible elimination of HCl in prescrubbers. The equilibrium calculations suggest that Hg retention is most sensitive to inlet HCl and O2 levels and the FGD temperature; weakly dependent on SO2 capture efficiency; and insensitive to HgCl2, NO, CA:S ratio, slurry dilution level in limestone FGDs, and MgSO3 levels in Mg/lime systems. Consequently, systems with prescrubbers to eliminate HCl probably retain less Hg than fully integrated FGDs. The analysis also predicts re-emission of Hg(O) but only for inlet O2 levels that are much lower than those in full-scale FGDs. PMID:16111136

  14. The impact of wet flue gas desulfurization scrubbing on mercury emissions from coal-fired power stations

    SciTech Connect

    Stephen Niksa; Naoki Fujiwara

    2005-07-01

    The article introduces a predictive capability for mercury (Hg) retention in any Ca-based wet flue gas desulfurization (FGD) scrubber, given Hg speciation at the FGD inlet, the flue gas composition, and the sulphur dioxide (SO{sub 2}) capture efficiency. A preliminary statistical analysis of data from 17 full-scale wet FGDs connects flue gas compositions, the extents of Hg oxidation at FGD inlets, and Hg retention efficiencies. These connections show that solution chemistry within the FGD determines Hg retention. A more thorough analysis based on thermochemical equilibrium yields highly accurate predictions for total Hg retention with no parameter adjustments. For the most reliable data, the predictions were within measurement uncertainties for both limestone and Mg/lime systems operating in both forced and natural oxidation mode. With the U.S. Environmental Protection Agency's (EPA) Information Collection Request (ICR) database, the quantitative performance was almost as good for the most modern FGDs, which probably conform to the very high SO{sub 2} absorption efficiencies assumed in the calculations. The large discrepancies for older FGDs are tentatively attributed to the unspecified SO{sub 2} capture efficiencies and operating temperatures and to the possible elimination of HCl in prescrubbers. The equilibrium calculations suggest that Hg retention is most sensitive to inlet HCl and O{sub 2} levels and the FGD temperature; weakly dependent on SO{sub 2} capture efficiency; and insensitive to HgCl{sub 2}, NO, CA:S ratio, slurry dilution level in limestone FGDs, and MgSO{sub 3} levels in Mg/lime systems. Consequently, systems with prescrubbers to eliminate HCl probably retain less Hg than fully integrated FGDs. The analysis also predicts re-emission of Hg{sub 0} but only for inlet O{sub 2} levels that are much lower than those in full-scale FGDs. 12 refs., 5 figs., 3 tabs.

  15. Alaska outer continental shelf beaufort sea planning area oil and gas lease sale 144. Final environmental impact statement. Volume 2

    SciTech Connect

    1996-05-01

    ;Table of Contents: Review and Analysis of Comments Received; Consultation and Coordination; Appendices; Resource Estimates and Exploration and Development Report; Oil-Spill-Risk Analysis; Alternative-Energy Sources as an Alternative to the OCS Program; MMS Alaska OCS Region Studies Program; Employment and Population Forecasts: Methodology and Supporting Tables for Section III.C.1, Economy of the North Slope Borough and Section IV.B.8; Effects on the Economy of the North Slope Borough; Endangered Species Act Section 7 Consultation and Documentation; and Fate and Effects of Exploratory Phase Oil and Gas Drilling Discharges in the Beaufort Sea Planning Area, Lease Sale 144.

  16. Impact of Shallow Convection on the Gas Hydrate Reservoir in the Gulf of Mexico Salt Tectonics Province

    NASA Astrophysics Data System (ADS)

    Wilson, A.; Ruppel, C.

    2005-12-01

    Previous modeling studies have suggested that subseafloor hydrogeology in the northern Gulf of Mexico could be strongly affected by the presence of salt domes, but these efforts were at the time limited to formulations that decoupled thermal and chemical buoyancy. The earlier studies concluded that downwelling associated with the negative buoyancy of dense briny fluids dominated upwelling associated with positive thermal buoyancy near salt domes. In this study, we use modern hydrologic models that fully couple thermal and chemical effects to re-examine this problem with particular focus on Gulf of Mexico gas hydrate reservoirs. We first demonstrate that even slight variations in seafloor bathymetry lead to the onset of shallow convection in marine sediments and that the existence of such convective patterns is not dependent on the presence of salt or the geometry of the salt body. Bathymetric highs are generally the loci of upwelling, while downwelling is concentrated in bathymetric lows. The length scale of the convective cells depends on the wavelength of seafloor topography but is generally hundreds to less than 2000 m, consistent with observational evidence one of us has earlier reported for the Mississippi Canyon and Garden Banks gas hydrate areas. The model calculations are consistent with the observed pattern of chloride, sulfate, and thermal anomalies, suggesting that the modeling results can be used to estimate the variation in the depth of hydrate stability and hydrate occurrence in these highly dynamic systems. Our simulations of the transient evolution of convective regimes near salt domes show that the near-surface, thermally-driven system eventually separates from the deeper, chemically-driven system dominated by stable, dense brines. In this scenario, the gas hydrate stability zone will change as a function of time due to the changing hydraulic regime in the sediments. Superposed on such hydraulic effects on the hydrate stability zone would be the influence of better understood processes such as sedimentation or erosion of the sedimentary column. Finally, we explicitly consider the role of faults in focusing fluids in these systems and conclude that faults can radically perturb the chemical and thermal conditions near salt domes to the point of entirely dominating the flow field and thus the gas hydrate stability field. The results are applied to zones of focused flux, such as the mud mounds in the Garden Banks and Mississippi Canyon areas and the seeps at Bush Hill, and to a zone of 'diffuse advective flux' characterized by a regional BSR at Keathley Canyon.

  17. Impact of Kr gas mixing in oxygen plasma etching of ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer films

    SciTech Connect

    Yoon, Joo-Won; Ohmi, Shun-ichiro; Park, Byung-Eun; Ishiwara, Hiroshi

    2008-10-20

    Oxygen plasma etching characteristics of ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer films are investigated. It was found in MFM (M: metal; F: ferroelectric) capacitors that plasma damage effects to the ferroelectric properties were insignificant when Au metal masks were used. On the contrary, C-V (capacitance versus voltage) characteristics were significantly degraded in plasma-etched MFIS (I: insulator; S: semiconductor) diodes. The origin of this phenomenon is speculated to be degradation of the SiO{sub 2}/Si interface by energetic oxygen ions and then mixing of Kr gas to the oxygen plasma is attempted to decrease the plasma damage.

  18. Strengthening of oxidation resistant materials for gas turbine applications. [treatment of silicon ceramics for increased flexural strength and impact resistance

    NASA Technical Reports Server (NTRS)

    Kirchner, H. P.

    1974-01-01

    Silicon nitride and silicon carbide ceramics were treated to form compressive surface layers. On the silicon carbide, quenching and thermal exposure treatments were used, and on the silicon nitride, quenching, carburizing, and a combination of quenching and carburizing were used. In some cases substantial improvements in impact resistance and/or flexural strength were observed. The presence of compressive surface stresses was demonstrated by slotted rod tests.

  19. Impact of Dynamic Loading on the Implant-abutment Interface Using a Gas-enhanced Permeation Test In Vitro

    PubMed Central

    Al-Jadaa, Anas; Attin, Thomas; Peltomäki, Timo; Heumann, Christian; Schmidlin, Patrick Roger

    2015-01-01

    Purpose : To assess implant leakage under static conditions as well as during and after dynamic loading. Materials and methods : Implants (Astra Tech (A), Biomet 3i (B) and Nobel Biocare (C)) were evaluated for leakage (n=8/group). Testing to assess the gas pressure change over time (hPa/min) and infiltrated fluid volume, was performed in a Gas Enhanced Permeation Test (GEPT) to qualify embedding. Implant apexes were then drilled, abutments were mounted and resin build-ups were fabricated. GEPT was reassessed. Samples were afterward mounted in a computer-controlled masticator while tested to bacterial leakage, they were daily observed for turbidity. Samples were then reassessed using GEPT. Dunnett's and Fisher's exact tests were utilized to compare implant and to analyze bacterial leakage. Results : Significant differences in GEPT values were shown after loading (p=0.034). Leakage resistance was best for B when compared to C (p=0.023). Samples with higher GEPT values demonstrated earlier bacterial leakage, occurring after 1 or 2 days (A=4, B=0, C=6) and showing favorability for implant system B (p=0.009). Conclusion : Implants leaking under static conditions had increased potential for bacterial leakage under dynamic conditions. As strongly correlating to sophisticated analytical methods, GEPT is a promising technique for assessing the overall implant system leakage resistance. PMID:25870719

  20. Potential impacts of electric power production utilizing natural gas, renewables and carbon capture and sequestration on US Freshwater resources.

    PubMed

    Tidwell, Vincent C; Malczynski, Leonard A; Kobos, Peter H; Klise, Geoffrey T; Shuster, Erik

    2013-08-01

    Carbon capture and sequestration (CCS) has important implications relative to future thermoelectric water use. A bounding analysis is performed using past greenhouse gas emission policy proposals and assumes either all effected capacity retires (lower water use bound) or is retrofitted (upper bound). The analysis is performed in the context of recent trends in electric power generation expansion, namely high penetration of natural gas and renewables along with constrained cooling system options. Results indicate thermoelectric freshwater withdrawals nationwide could increase by roughly 1% or decrease by up to 60% relative to 2009 levels, while consumption could increase as much as 21% or decrease as much as 28%. To identify where changes in freshwater use might be problematic at a regional level, electric power production has been mapped onto watersheds with limited water availability (where consumption exceeds 70% of gauged streamflow). Results suggest that between 0.44 and 0.96 Mm(3)/d of new thermoelectric freshwater consumption could occur in watersheds with limited water availability, while power plant retirements in these watersheds could yield 0.90 to 1.0 Mm(3)/d of water savings. PMID:23789965

  1. CO2 injectivity in saline aquifers: The impact of non-Darcy flow, phase miscibility, and gas compressibility

    NASA Astrophysics Data System (ADS)

    Mijic, Ana; LaForce, Tara C.; Muggeridge, Ann H.

    2014-05-01

    A key aspect of CO2 storage is the injection rate into the subsurface, which is limited by the pressure at which formation starts to fracture. Hence, it is vital to assess all of the relevant processes that may contribute to the pressure increase in the aquifer during CO2 injection. Building on an existing analytical solution for immiscible and spatially varying non-Darcy flow, this paper presents a mathematical model that accounts for combined effects of non-Darcy flow, phase miscibility, and gas compressibility in radial two-phase displacements. Results show that in low-permeability formations when CO2 is injected at high rates, non-Darcy simulations forecast better displacement efficiency compared to flow under Darcy conditions. This will have a positive effect on the formation CO2 storage capacity. This, however, comes at the cost of increased well pressures. More favorable estimations of the pressure buildup are obtained when CO2 compressibility is taken into account because reservoir pressures are reduced due to the change in the gas phase properties. Also, non-Darcy flow results in a significant reduction in halite precipitation in the near-well region, with a positive effect on CO2 injectivity. In the examples shown, non-Darcy flow conditions may lead to significantly different pressure and saturation distributions in the near-well region, with potentially important implications for CO2 injectivity.

  2. NATURAL GAS VARIABILITY IN CALIFORNIA: ENVIRONMENTAL IMPACTS AND DEVICE PERFORMANCE EXPERIMENTAL EVALUATION OF POLLUTANT EMISSIONS FROM RESIDENTIAL APPLIANCES

    SciTech Connect

    Singer, Brett C.; Apte, Michael G.; Black, Douglas R.; Hotchi, Toshifumi; Lucas, Donald; Lunden, Melissa M.; Mirer, Anna G.; Spears, Michael; Sullivan, Douglas P.

    2009-12-01

    The effect of liquefied natural gas on pollutant emissions was evaluated experimentally with used and new appliances in the laboratory and with appliances installed in residences, targeting information gaps from previous studies. Burner selection targeted available technologies that are projected to comprise the majority of installed appliances over the next decade. Experiments were conducted on 13 cooktop sets, 12 ovens, 5 broiler burners, 5 storage water heaters, 4 forced air furnaces, 1 wall furnace, and 6 tankless water heaters. Air-free concentrations and fuel-based emission factors were determined for carbon monoxide, nitrogen oxides, nitrogen dioxide, and the number of (predominantly ultrafine) particles over complete burns?including transient effects (device warm-up and intermittent firing of burners) following ignition--and during more stable end-of-burn conditions. Formaldehyde was measured over multi-burn cycles. The baseline fuel was Northern California line gas with Wobbe number (a measure of fuel energy delivery rate) of 1320-1340; test fuels had Wobbe numbers of roughly 1390 and 1420, and in some cases 1360. No ignition or operational problems were observed during test fuel use. Baseline emissions varied widely across and within burner groups and with burner operational mode. Statistically significant emissions changes were observed for some pollutants on some burners.

  3. Impact of alternative fuels on emissions characteristics of a gas turbine engine - part 2: volatile and semivolatile particulate matter emissions.

    PubMed

    Williams, Paul I; Allan, James D; Lobo, Prem; Coe, Hugh; Christie, Simon; Wilson, Christopher; Hagen, Donald; Whitefield, Philip; Raper, David; Rye, Lucas

    2012-10-01

    The work characterizes the changes in volatile and semivolatile PM emissions from a gas turbine engine resulting from burning alternative fuels, specifically gas-to-liquid (GTL), coal-to-liquid (CTL), a blend of Jet A-1 and GTL, biodiesel, and diesel, to the standard Jet A-1. The data presented here, compares the mass spectral fingerprints of the different fuels as measured by the Aerodyne high resolution time-of-flight aerosol mass spectrometer. There were three sample points, two at the exhaust exit plane with dilution added at different locations and another probe located 10 m downstream. For emissions measured at the downstream probe when the engine was operating at high power, all fuels produced chemically similar organic PM, dominated by C(x)H(y) fragments, suggesting the presence of long chain alkanes. The second largest contribution came from C(x)H(y)O(z) fragments, possibly from carbonyls or alcohols. For the nondiesel fuels, the highest loadings of organic PM were from the downstream probe at high power. Conversely, the diesel based fuels produced more organic material at low power from one of the exit plane probes. Differences in the composition of the PM for certain fuels were observed as the engine power decreased to idle and the measurements were made closer to the exit plane. PMID:22913312

  4. Incineration of animal by-products - The impact of selected parameters on the flux of flue gas enthalpy.

    PubMed

    Bujak, Janusz; Sitarz, Piotr

    2016-04-01

    This paper presents model analyses and tests of animal by-product waste thermal treatment plants. A schedule of tests was prepared, and 62,024 cases of system operation were analysed. A map/work field of the tested plant was drawn up on the basis thereof. Calculations were made following an algorithm described by Bujak (2015a) written in the VBA (Visual Basic for Application) language. The tests showed that when incinerating animal waste, the flux of physical enthalpy of the flue gas from the afterburner chamber depends on numerous design and operating parameters. The most important include the following: humidity and flux of the waste, concentration of oxygen in the flue gas in the afterburner chamber and loss of heat flux to the atmosphere through the external surfaces of the plant. Individual design and operating parameters can be selected so that the process of incineration is ensured without additional fuel. The performed analyses were verified against the actual object at the industrial scale using a meat plant that manufactures ham and processes beef, pork and poultry with a capacity of 150tonnes/day. The production process waste included mainly bones and - in much smaller quantities - meat and bone meal, at 17tonnes/day. The performed tests and analyses can be used to optimise the operation of the waste thermal treatment plant at the stages of design and operation. PMID:26926784

  5. Effect of placements (horizontal with vertical) on gas-solid flow and particle impact erosion in gate valve

    NASA Astrophysics Data System (ADS)

    Lin, Zhe; Zhu, Linhang; Cui, Baoling; Li, Yi; Ruan, Xiaodong

    2014-12-01

    Gate valve has various placements in the practical usages. Due to the effect of gravity, particle trajectories and erosions are distinct between placements. Thus in this study, gas-solid flow properties and erosion in gate valve for horizontal placement and vertical placement are discussed and compared by using Euler-Lagrange simulation method. The structure of a gate valve and a simplified structure are investigated. The simulation procedure is validated in our published paper by comparing with the experiment data of a pipe and an elbow. The results show that for all investigated open degrees and Stokes numbers (St), there are little difference of gas flow properties and flow coefficients between two placements. It is also found that the trajectories of particles for two placements are mostly identical when St « 1, making the erosion independent of placement. With the increase of St, the distinction of trajectories between placements becomes more obvious, leading to an increasing difference of the erosion distributions. Besides, the total erosion ratio of surface T for horizontal placement is two orders of magnitudes larger than that for vertical placement when the particle diameter is 250μm.

  6. MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM-PRELIMINARY REPORT

    SciTech Connect

    Zamecnik, J.; Choi, A.

    2010-08-18

    The Defense Waste Processing Facility (DWPF) is currently evaluating an alternative Chemical Process Cell (CPC) flowsheet to increase throughput. It includes removal of the steam-stripping step, which would significantly reduce the CPC processing time and lessen the sampling needs. However, its downside would be to send 100% of the mercury that comes in with the sludge straight to the melter. For example, the new mercury content in the Sludge Batch 5 (SB5) melter feed is projected to be 25 times higher than that in the SB4 with nominal steam stripping of mercury. This task was initiated to study the impact of the worst-case scenario of zero-mercury-removal in the CPC on the DWPF melter offgas system. It is stressed that this study is intended to be scoping in nature, so the results presented in this report are preliminary. In order to study the impact of elevated mercury levels in the feed, it is necessary to be able to predict how mercury would speciate in the melter exhaust under varying melter operating conditions. A homogeneous gas-phase oxidation model of mercury by chloride was developed to do just that. The model contains two critical parameters pertaining to the partitioning of chloride among HCl, Cl, Cl{sub 2}, and chloride salts in the melter vapor space. The values for these parameters were determined at two different melter vapor space temperatures by matching the calculated molar ratio of HgCl (or Hg{sub 2}Cl{sub 2}) to HgCl{sub 2} with those measured during the Experimental-Scale Ceramic Melter (ESCM) tests run at the Pacific Northwest National Laboratory (PNNL). The calibrated model was then applied to the SB5 simulant used in the earlier flowsheet study with an assumed mercury stripping efficiency of zero; the molar ratio of Cl-to-Hg in the resulting melter feed was only 0.4, compared to 12 for the ESCM feeds. The results of the model run at the indicated melter vapor space temperature of 650 C (TI4085D) showed that due to excessive shortage of chloride, only 6% of the mercury fed is expected to get oxidized, mostly as HgCl, while the remaining mercury would exist either as elemental mercury vapor (90%) or HgO (4%). Noting that the measured chloride level in the SB5 qualification sample was an order of magnitude lower than that used in the SB5 simulant, the degree of chloride shortage will be even greater. As a result, the projected level of HgCl in the actual SB5 melter exhaust will be even lower than 6% of the total mercury fed, while that of elemental mercury is likely to be greater than 90%. The homogeneous oxidation of mercury in the off-gas was deemed to be of primary importance based on the postulation that mercury and other volatile salts form submicron sized aerosols upon condensation and thus remain largely in the gas stream downstream of the quencher where they can deposit in the off-gas lines, Steam-Atomized Scrubbers (SAS), and High-Efficiency Mist Eliminator (HEME). Formation of these submicron semi-volatile salts in the condensate liquid is considered to be unlikely, so the liquid phase reactions were considered to be less important. However, subsequent oxidation of mercury in the liquid phase in the off-gas system was examined in a simplified model of the off-gas condensate. It was found that the condensate chemistry was consistent with further oxidation of elemental mercury to Hg{sub 2}Cl{sub 2} and conversion of HgO to chlorides. The results were consistent with the available experimental data. It should also be noted that the model predictions presented in this report do not include any physically entrained solids, which typically account for much of the off-gas carryover on a mass basis. The high elemental mercury vapor content predicted at the DWPF Quencher inlet means that physically entrained solids could provide the necessary surface onto which elemental mercury vapor could condense, thereby coating the solids as well as the internal surfaces of the off-gas system with mercury. Clearly, there are many process benefits to be gained by removing the steam-stripping step from the CPC cycle. The goal of this task was to study what adverse impact the zero-mercury-removal scenario would have on the DWPF melter off-gas system operation. It is stressed again that this study was intended to be scoping in nature, so the results presented in this report are preliminary. Any further substantiation of these results for actual implementation into the DWPF flowsheet would require an in-depth modeling study of all three reaction zones, including the aqueous-phase reactions in the quencher, OGCT, Steam Atomized Scrubber (SAS), and off-gas condenser with recirculated condensate, and the proof-of-principle experiments.

  7. Differential impact of immediate total deregulation of wellhead prices of natural gas on minority and low-income homeowners: a general review and a case study in the Washington, DC area

    SciTech Connect

    Green, R.D.; Gilbert, H.R.

    1983-01-01

    In this study, the authors evaluate the impact of total deregulation of wellhead prices of natural gas on various strata of the residential consuming population, and compare it to the baseline impact of a continuation of the Natural Gas Policy Act of 1978. They found that minority and poverty homeowners will suffer greater relative welfare losses than their white and non-poverty counterparts. They developed quantitative estimates of the extent of these differentials, and offered some policy proposals suggested by these findings. 54 refs., 8 figs., 68 tabs.

  8. Assessment of Emerging Regional Air Quality (AQ) and Greenhouse Gas (GHG) Impacts