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1

Determination of the propylene oxide-hemoglobin adduct by gas chromatography-electron impact ionization mass spectrometry.  

PubMed

A gas chromatography-mass spectrometry method was developed for the determination of the propylene oxide (PO)-hemoglobin adduct. The adduct was identified as hydroxy propyl valine (HPV), and released from globin by the modified Edman degradation and extracted with ethyl ether. HPV and deuterated HPV (d6-HPV) were synthesized for identification and quality control. d6-HPV was used as an internal reference standard. The dried extract was completely derivatized with N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA). The method detection limit (MDL) of the assay was 10 pmole/g for HPV, based on assayed hemoglobin of 0.1 g. The method was applied to the determination of the PO-hemoglobin adduct formed in young female Sprague-Dawley rats after treatment for 4 and 5 weeks with 5 and 10 mM PO via drinking water. HPV was detected by the proposed procedure. After 4 weeks, the concentration of HPV was 6.75 nmole/g hemoglobin during treatment with 5 mM, and 80.26 nmole/g hemoglobin during treatment with 10 mM. The adduct level in 5 weeks increased up to about 51.47 nmole/g during treatment with 5 mM PO in the drinking water and up to about 120.27 nmole/g during treatment with 10 mM PO. This method was also applied to determine the concentrations of HPV in the blood of 20 persons living near the Ulsan petroleum industrial complex in Korea. As a result, HPV-hemoglobin adduct was detected in the concentration range 0-1100 pmol/g in the human blood samples. PMID:16718639

Shin, Ho-Sang; Ahn, Hye-Sil

2006-06-01

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

Part-per-trillion determination of chlorobenzenes in water using dispersive liquid–liquid microextraction combined gas chromatography–electron capture detection  

Microsoft Academic Search

In this study, a simple, rapid and efficient method, dispersive liquid–liquid microextraction (DLLME) combined gas chromatography–electron capture detection (GC–ECD), for the determination of chlorobenzenes (CBs) in water samples, has been described. This method involves the use of an appropriate mixture of extraction solvent (9.5?l chlorobenzene) and disperser solvent (0.50ml acetone) for the formation of cloudy solution in 5.00ml aqueous sample

Reyhaneh Rahnama Kozani; Yaghoub Assadi; Farzaneh Shemirani; Mohammad-Reza Milani Hosseini; Mohammad Reza Jamali

2007-01-01

4

Quantitative detection of trace explosive vapors by programmed temperature desorption gas chromatography-electron capture detector.  

PubMed

The direct liquid deposition of solution standards onto sorbent-filled thermal desorption tubes is used for the quantitative analysis of trace explosive vapor samples. The direct liquid deposition method yields a higher fidelity between the analysis of vapor samples and the analysis of solution standards than using separate injection methods for vapors and solutions, i.e., samples collected on vapor collection tubes and standards prepared in solution vials. Additionally, the method can account for instrumentation losses, which makes it ideal for minimizing variability and quantitative trace chemical detection. Gas chromatography with an electron capture detector is an instrumentation configuration sensitive to nitro-energetics, such as TNT and RDX, due to their relatively high electron affinity. However, vapor quantitation of these compounds is difficult without viable vapor standards. Thus, we eliminate the requirement for vapor standards by combining the sensitivity of the instrumentation with a direct liquid deposition protocol to analyze trace explosive vapor samples. PMID:25145416

Field, Christopher R; Lubrano, Adam; Woytowitz, Morgan; Giordano, Braden C; Rose-Pehrsson, Susan L

2014-01-01

5

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...

6

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

PubMed

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

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

2015-02-01

7

Determination of pentachlorophenol residue in meat and fish by gas chromatography-electron capture detection and gas chromatography-mass spectrometry with accelerated solvent extraction.  

PubMed

A novel analytical method, using gas chromatography-electron capture detection (GC-ECD) and GC-mass spectrometry detection (MS), was developed for the qualitative and quantitative measurement of pentachlorophenol in meat and fish. The analyte was extracted by methanol-2% trichloroacetic acid (3/1, v/v) with accelerated solvent extraction (ASE). The eluted fraction was evaporated and derivatized with acetic anhydride-pyridine (1/1, v/v) for GC-ECD analysis and GC-MS confirmation. The parameters for extraction pressure, temperature and cycle of ASE, cleanup, derivatization and analysis procedure were optimized. The averaged decision limits and detection capability of the method were in the ranges of 0.25-0.41 and 0.49-1.01 µg/kg in the muscle and liver of swine and bovine and in the muscle of carp and finless eel, respectively. Spiked recoveries from levels of 0.5-2.0 µg/kg were found to be more than 71.1%, with relative standard deviation less than 14.7% in GC-ECD and GC-MS. This rapid and reliable method can be used for the characterization and quantification of residues of pentachlorophenol in animal and fish tissues. PMID:23690067

Zhao, Dongmei

2014-01-01

8

Simultaneous analysis of polychlorinated biphenyls and organochlorine pesticides in seawater samples by membrane-assisted solvent extraction combined with gas chromatography-electron capture detector and gas chromatography-tandem mass spectrometry.  

PubMed

A highly efficient and environment-friendly membrane-assisted solvent extraction system combined with gas chromatography-electron capture detector was applied in the simultaneous determination of 17 polychlorinated biphenyls and organochlorine pesticides in seawater samples. Variables affecting extraction efficiency, including extraction solvent used, stirring rate, extraction time, and temperature, were optimized extensively. Under optimal extraction conditions, recoveries between 76.9% and 104.6% in seawater samples were achieved, and relative standard deviation values below 10% were obtained. The limit of detection (signal-to-noise ratio=3) and limit of quantification (signal-to-noise ratio=10) of 17 polychlorinated biphenyls and organochlorine pesticides in seawater ranged from 0.14ngL(-1) to 0.36ngL(-1) and 0.46ngL(-1) to 1.19ngL(-1), respectively. Matrix effects on extraction efficiency were evaluated by comparing with the results obtained using tap water. The extraction effect of developed membrane-assisted solvent extraction method was further demonstrated by gas chromatography-tandem mass spectrometry which can provide structural information of the analytes for more accurate identification, and results identical to those produced by gas chromatography-electron capture detector were obtained. These findings demonstrate the applicability of the developed membrane-assisted solvent extraction determination method for coupling to gas chromatography-electron capture detector or tandem mass spectrometry for determining polychlorinated biphenyls and organochlorine pesticides in seawater samples. PMID:25310709

Shi, Xizhi; Tang, Zigang; Sun, Aili; Zhou, Lei; Zhao, Jian; Li, Dexiang; Chen, Jiong; Pan, Daodong

2014-12-01

9

Analysis of N-nitrosamines in water by isotope dilution gas chromatography-electron ionisation tandem mass spectrometry.  

PubMed

A method has been developed for the determination of eight N-nitrosamines in drinking water and treated municipal effluent. The method uses solid phase extraction (SPE), gas chromatography (GC) and analysis by tandem mass spectrometry (MS-MS) with electron ionization (EI). The target compounds are N-nitrosodimethylamine (NDMA), N-nitrosomethyethylamine (NMEA), N-nitrosodiethylamine NDEA), N-nitrosodipropylamine (NDPA), N-nitrosodi-n-butylamine (NDBuA), N-nitrosodiphenylamine (NDPhA), N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip), N-nitrosomorpholine (NMorph). The use of direct isotope analogues for isotope dilution analysis of all analytes ensures accurate quantification, accounting for analytical variabilities that may occur during sample processing, extraction and instrumental analysis. Method detection levels (MDLs) were determined to describe analyte concentrations sufficient to provide a signal with 99% certainty of detection. The established MDLs for all analytes were 0.4-4 ng L(-1) in a variety of aqueous matrices. Sample matrices were observed to have only a minor impact on MDLs and the method validation confirmed satisfactory method stability over intra-day and inter-day analyses of tap water and tertiary treated effluent samples. PMID:22967534

McDonald, James A; Harden, Nick B; Nghiem, Long D; Khan, Stuart J

2012-09-15

10

[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

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

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

2011-05-01

11

Group-selective enrichment and determination of pyrethroid insecticides in aquaculture seawater via molecularly imprinted solid phase extraction coupled with gas chromatography-electron capture detection.  

PubMed

Two types of molecularly imprinted polymers (MIPs) for the simultaneous determination of six pyrethroid insecticides have been developed using deltamethrin (D-MIPs) and cypermethrin (C-MIPs) as template molecules. A comparison of the performance of D-MIPs, C-MIPs, and the corresponding non-imprinted polymers (NIPs) were conducted. Stronger group-selective interactions between the C-MIPs and the six pyrethroid insecticides were achieved. The MISPE method based on the C-MIPs displayed higher extraction recoveries (86.4-96.0%) with RSD values ranging from 2.4 to 7.8% for the six pyrethroid insecticides in aquaculture seawater. After the C-MIP cartridge procedure, the limits of detection and quantification for fenvalerate, deltamethrin, cypermethrin, cyfluthrin, and bifenthrin were in the 16.6-37.0 and 55.3-109.1 ng L?¹ ranges, respectively, and 0.68 and 2.26 ?g L?¹ for phenothrin, respectively. The proposed MISPE method coupled with gas chromatography-electron capture detection was successfully used for the determination of the six pyrethroid insecticides in aquaculture seawater. PMID:22265776

Shi, Xizhi; Liu, Jinghua; Sun, Aili; Li, Dexiang; Chen, Jiong

2012-03-01

12

Simultaneous determination of cyanide and carbonyls in cyanogenic plants by gas chromatography-electron capture/photoionization detection.  

PubMed

A new method to simultaneously detect cyanide and carbonyl compounds arising from cyanogenic glycosides in plants is described. A portable gas chromatograph.housing two detectors using a single carrier gas is employed to measure the carbonyl compounds (photoionization detector) and cyanide as its cyanogen chloride derivative (electron capture detector) from the headspace of a plant sample. This method affords in-field, rapid screening of plants to determine cyanogenicity. Good agreement was seen between this method for cyanide determination and two traditional field cyanide test kits. Detection of both the cyanide and the carbonyl compound(s) allows for confirmation of the presence of cyanogenic glycosides and eliminates the problem of false positives often seen in traditional cyanide test kits. Gas phase limits of detection for cyanide, acetone, butanone, and benzaldehyde were 69, 41, 105, and 0.39 parts per billion by volume (ppbv), respectively, allowing sensitive detection of cyanogenic glycoside breakdown products. The method's utility for screening cyanogenic plants is demonstrated, and it should be useful for screening cyanogenic foodstuffs to determine suitability for consumption. PMID:12475032

Curtis, Abigale J; Grayless, C Charles; Fall, Ray

2002-11-01

13

Analysis of corky off-flavour compounds at ultra trace level with multidimensional gas chromatography-electron capture detection.  

PubMed

A robust method for routine quality control of corky off-flavour compounds in wine and cork soak matrices has been established. Based on an automated headspace solid phase microextraction (HS-SPME), the method needs only marginal sample preparation and achieves low (sub-ng L(-1)) trace level detection limits (LODs) for the most relevant off-flavour compounds, such as 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole (TeCA) and 2,4,6-tribromoanisole (TBA). Particularly for wine matrix, reliable trace level quantification had only been achieved after applying heart-cutting multidimensional gas chromatography (MDGC). Using a halogen-sensitive electron capture detector (ECD) and quantification with a stable isotope dilution assay (SIDA), LODs of 0.1ng L(-1) for TCA, TeCA and TBA could be obtained. Since a SIDA based quantification method is used with a non-mass spectrometric detector, the necessary chromatographic resolution of internal standard and target analyte peaks resulted from the use of highly deuterated [(2)H(5)]-isotopologues. PMID:23219330

Slabizki, Petra; Schmarr, Hans-Georg

2013-01-01

14

Determination of pyrethroid metabolites in human urine using liquid phase microextraction coupled in-syringe derivatization followed by gas chromatography/electron capture detection.  

PubMed

Metabolites of synthetic pyrethroids such as cis-3-(2,2-dibromovinyl)-2,2-di-methylcyclo-propane-1-carboxylic acid, cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid), 3-phenoxybenzoic acid (3-PBA), and 4-fluoro-3-PBA are biomarkers for exposure to phenothrin, tetramethrin, cyfluthrin, cypermethrin, deltamethrin, and permethrin. In this study, the pyrethroid metabolites in workers' urine samples were monitored for the first time with a novel sample pretreatment process combining hollow fiber liquid phase microextraction (HF-LPME) and in-syringe derivatization (ISD) followed by gas chromatography-electron capture detector (GC-ECD) analysis. A micro-syringe pre-filled with derivatizing agents and syringe needle connected to an extracting solvent impregnated hollow fiber segment was used as the LPME probe. Pyrethroid metabolites were extracted and enriched simultaneously from urine samples by HF-LPME sampling and acid hydrolysis at 70 °C for 10 min. After sampling, the ISD was performed by mixing the extracting solution and derivatizing agents through plunger movements, followed by GC-ECD analysis. Parameters influencing the HF-LPME efficiency and ISD were investigated and optimized. Under optimum conditions, the method provided enrichment factors of 69.8-154.6, repeatability from 5.0 to 12% (n = 5), and good linearity (R(2) = 0.9980-0.9998) for interested analytes spiked in urine samples. The method detection limits ranged from 1.6 to 17 ng/mL. A comparison was performed between the proposed method and conventional methods. The proposed method was applied to analyze pyrethroid metabolites in the urine samples collected from workers of pesticide formulation plants. The results suggested that the proposed HF-LPME coupled ISD method was a rapid, simple, efficient, and eco-friendly technique in the biomonitoring of metabolites of pyrethroids in workers' urine. PMID:21667061

Lin, Chiu-Hwa; Yan, Cheing-Tong; Kumar, Ponnusamy Vinoth; Li, Hong-Ping; Jen, Jen-Fon

2011-08-01

15

Determination of the enantiomer fraction of PBB 149 by gas chromatography/electron capture negative ionization tandem mass spectrometry in the selected reaction monitoring mode.  

PubMed

Enantioselective determination of the atropisomers of 2,2',3,4',5',6-hexabromobiphenyl (PBB 149) in a purified sample from a bird egg was attempted in this work. By application of the classic method for PBB determination, i.e. gas chromatography coupled to electron capture negative ionization mass spectrometry (GC/ECNI-MS) using the bromide ions, the enantiomers interfered with another brominated compound. Subsequent measurements clarified that this interference did not occur in the mass chromatogram of the molecular ion of PBB 149. Therefore, a GC/ECNI tandem mass spectrometry (MS/MS) method was developed, based on the fragmentation of [M]-. A suitable precursor-product ion transition was found for m/z 627.5 --> 80 +/- 1.5, representing the most abundant ion trace of the molecular ion and the bromide ions. Optimization of the ion source temperature, the methane gas pressure, and the collision voltages resulted in a robust method that could solve the problem. Subsequent injections of a technical PBB product (Firemaster BP-6) resulted in the anticipated racemic proportion (enantiomer fraction (EF) = 0.50 +/- 0.02 (n = 8)). By contrast, the EF in the purified extract of a bird egg was found to be 0.42 +/- 0.02 (n = 10), indicative of a significant enantioenrichment of the second eluting atropisomer. Additional measurements were performed on a non-chiral column. These measurements allowed for the detection of 16 hexabromobiphenyls (hexa-BBs) in Firemaster BP-6. These comparisons verified that PBB 149 enantiomers did not interfere with an isomer that could falsify the enantiomer fraction in the sample. The novel method using GC/ECNI-MS/MS in the selected reaction monitoring (SRM) mode was eight times more sensitive than application of conventional GC/ECNI-MS selected ion monitoring (SIM) analysis of the molecular ion. PMID:16302204

von der Recke, Roland; Mariussen, Espen; Berger, Urs; Götsch, Arntraut; Herzke, Dorte; Vetter, Walter

2005-01-01

16

Use of green coating (cork) in solid-phase microextraction for the determination of organochlorine pesticides in water by gas chromatography-electron capture detection.  

PubMed

A novel method for the determination of organochlorine pesticides in water samples with extraction using cork fiber and analysis by gas chromatography with electron capture detector was developed. Also, the procedure to extract these pesticides with DVB/Car/PDMS fiber was optimized. The optimization of the variables involved in the extraction of organochlorine pesticides using the aforementioned fibers was carried out by multivariate design. The optimum extraction conditions were sample temperature 75°C, extraction time 60min and sodium chloride concentration 10% for the cork fiber and sample temperature 50°C and extraction time 60min (without salt) for the DVB/Car/PDMS fiber. The quantification limits for the two fibers varied between 1.0 and 10.0ngL(-1). The linear correlation coefficients were >0.98 for both fibers. The method applied with the use of the cork fiber provided recovery values between 60.3 and 112.7 and RSD?25.5 (n=3). The extraction efficiency values for the cork and DVB/Car/PDMS fibers were similar. The results show that cork is a promising alternative as a coating for SPME. PMID:25618687

Neves Dias, Adriana; Simão, Vanessa; Merib, Josias; Carasek, Eduardo

2015-03-01

17

Microwave-assisted headspace controlled temperature liquid-phase microextraction of chlorophenols from aqueous samples for gas chromatography-electron capture detection.  

PubMed

A modified headspace liquid-phase microextraction (HS-LPME) method was studied for the extraction of chlorophenols (CPs) from aqueous samples with complicated matrices, before gas chromatographic (GC) analysis with electron capture detection (ECD). Microwave heating was applied to accelerate the evaporation of CPs into the headspace, and an external-cooling system was used to control the sampling temperature. Conditions influencing extraction efficiency, such as the LPME-solvent, the sampling position of LPME, the sampling temperature, microwave power, and irradiation time (the same as sampling time), sample pH, and salt addition were thoroughly optimized. Experimental results indicated that the extraction of CPs from a 10mL aquatic sample (pH 1.0) was achieved with the best efficiency through the use of 1-octanol as solvent, microwave irradiation of 167W, and sampling at 45 degrees C for 10min. The detections were linear in the concentration of 5.0-100microg/L for 2,4-dichlorophenol (2,4-DCP), and 0.5-10microg/L for 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP) and pentachlorophenol (PCP). Detection limits were found to be 0.7, 0.04, 0.07, and 0.08microg/L for 2,4-DCP, 2,4,6-TCP, 2,3,4,6-TeCP, and PCP, respectively. A landfill leachate sample was analyzed with recovery between 83 and 102%. The present method was proven to serve as a simple, sensitive, and rapid procedure for CP analysis in an aqueous sample. PMID:18760797

Shi, Yi-An; Chen, Ming-Zen; Muniraj, Sarangapani; Jen, Jen-Fon

2008-10-17

18

A rapid novel derivatization of amphetamine and methamphetamine using 2,2,2-trichloroethyl chloroformate for gas chromatography electron ionization and chemical ionization mass spectrometric analysis.  

PubMed

Amphetamine and methamphetamine are commonly abused central nervous system stimulants. We describe a rapid new derivatization of amphetamine and methamphetamine using 2,2,2-trichloroethyl chloroformate for gas chromatography-mass spectrometric analysis. Amphetamine and methamphetamine, along with N-propyl amphetamine (internal standard), were extracted from urine using 1-chlorobutane. The derivatization with 2,2,2-trichloroethyl chloroformate can be achieved at room temperature in 10 minutes. The electron ionization mass spectrum of amphetamine 2,2,2-trichloroethyl carbamate showed two weak molecular ions at m/z 309 and 311, but showed diagnostic strong peaks at m/z 218, 220, and 222. In contrast, chemical ionization of the mass spectrum of amphetamine 2,2,2-trichloroethyl carbamate showed strong (M + 1) ions at m/z 310 and 312 and other strong diagnostic peaks at m/z 274 and 276. The major advantages of this derivative are the presence of a diagnostic cluster of peaks due to the isotopic effect of three chlorine atoms (isotopes 35 and 37) in the derivatized molecule and the relative ease of its preparation. We also observed strong molecular ions for derivatized methamphetamine in the chemical ionization mass spectrum, but the molecular ions were very weak in the electron ionization mass spectrum. We used the scan mode of mass spectrometry in all analyses. When using a urine standard containing 1,000 ng/mL of amphetamine (a 7.4-micromol/L concentration) and methamphetamine (a 6.7-micromol/L concentration), the within-run precisions were 4.8% for amphetamine and 3.6% for methamphetamine. The corresponding between-run precisions were 5.3% for amphetamine and 6.7% for methamphetamine. The assay was linear for amphetamine and methamphetamine concentrations of 250 to 5,000 ng/mL (amphetamine, 1.9-37.0 micromol/L; methamphetamine, 1.7-33.6 micromol/L). The detection limit was 100 ng/mL (amphetamine, 0.74 micromol/L; methamphetamine, 0.67 micromol/L) using the scan mode of electron ionization mass spectrometry. We observed good a correlation between the concentrations of amphetamine and methamphetamine in five urine specimens positive for amphetamines using the more conventional pentafluoropropionyl derivative and our new derivative using 2,2,2-trichloroethyl chloroformate. PMID:9576569

Dasgupta, A; Spies, J

1998-05-01

19

Analysis of C(14)-C(17) Polychloro-n-alkanes in Environmental Matrixes by Accelerated Solvent Extraction-High-Resolution Gas Chromatography/Electron Capture Negative Ion High-Resolution Mass Spectrometry.  

PubMed

A method for quantifying medium-chain (C(14)-C(17)) polychloroalkanes (mPCAs) in environmental matrixes by accelerated solvent extraction high-resolution gas chromatography/electron capture negative ion high-resolution mass spectrometry in the selected ion monitoring mode is presented. The formula group abundance profiles of industrial mPCA mixtures, which are used as standards, and of samples are first determined by monitoring [M - Cl](-) ions of specific m/z values corresponding to the molecular formulas present and by correcting the integrated ion signals for the fractional abundance of the specific m/z value monitored and the number of chlorine atoms in the formula group. mPCA concentrations in environmental samples are then determined by comparing the response of a specific m/z peak in the sample to that in the standard. Extraction recoveries of mPCAs from spiked fish and sodium sulfate (in place of sediment) were >79%. Method detection limits were 13 ng/g for fish and 1.4 ng/?L for sediment, while the analytical detection limit was ?200 pg, at a signal-to-noise ratio of 4:1. By this method, mPCAs were detected in biota and sediment from the mouth of the Detroit River (MI) and ranged from 70 to 900 ng/g. The simultaneous quantitation of C(10)-C(13) (sPCAs) and C(14)-C(17) PCAs, based on monitoring two specific m/z peaks, one characteristic of sPCAs and the other of mPCAs, is also demonstrated. PMID:21662834

Tomy, G T; Stern, G A

1999-11-01

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...

21

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...

22

Highly selective and sensitive gas chromatography-electron-capture negative-ion mass spectrometry method for the indirect enantioselective identification of 2- and 3-hydroxy fatty acids in food and biological samples.  

PubMed

A gas chromatographic (GC) method is described for the indirect enantioresolution of 2- and 3-hydroxy fatty acids (OH-FAs). It combines the derivatization of each alkylated enantiomer and the subsequent transfer with (R)-(-)-alpha-methoxy-alpha-trifluoromethylphenylacetyl chloride [(R)-(-)-MTPA-Cl, Mosher's reagent] into a diastereomeric (S)-MTPA derivative. The enantiomers of each derivatized OH-FA were well separated on three non-chiral GC-columns (CP-Sil 2, CP-Sil 8/20% C18 and VF-5ms). The derivatives were detected with high sensitivity by GC with electron-capture detection (GC/ECD) and electron-capture negative-ion mass spectrometry (GC/ECNI-MS) because of their enhanced electron-capturing properties. When applied to sunflower oil spiked with a small amount of a racemic 2-OH-FA, the present method allowed for a highly selective identification without influence from the sample matrix. For more complex samples such as wool wax, GC/ECNI-MS was superior to GC/ECD, since the high sensitivity of this method was linked with high selectivity. Using GC/ECNI-MS in the selected ion monitoring (SIM) mode, 16 enantiopure 2-OH-FAs were detected in a wool wax sample. PMID:17292906

Jenske, Ramona; Vetter, Walter

2007-04-01

23

Polymer-functionalized single-walled carbon nanotubes as a novel sol-gel solid-phase micro-extraction coated fiber for determination of poly-brominated diphenyl ethers in water samples with gas chromatography-electron capture detection.  

PubMed

Single-walled carbon nanotubes (SWNTs) were functionalized with a hydroxyl-terminated silicone oil (TSO-OH). It is synthesized by the reactions of carbonyl chloride groups on the surface of SWNTs and hydroxyl groups of silicone oil (TSO-OH). The functionalized product SWNTs-TSO-OH was first used as precursor and selective stationary phase to prepare the sol-gel derived poly(SWNTs-TSO-OH) solid-phase microextraction (SPME) fiber for determination of polybrominated diphenyl ethers (PBDEs) in water samples. The possible major reaction of the sol-gel coating process was discussed and confirmed by IR spectra, Raman spectroscopy, and scanning electron microscopy. Some parameters of SPME fiber for the determination of PBDEs were investigated by headspace SPME/gas chromatography with electron-capture detection (HS-SPME/GC-ECD). Compared with the commercial SPME fiber, the new coated fiber showed higher extraction efficiency to PBDEs, better thermal stability (over 340 degrees C), and longer life span (over 200 times). All of these advantages are mainly due to the incorporation of SWNTs, which enhanced the pi-pi interaction with PBDEs and increased the surface area of extraction in contact with the sample. Moreover, the sol-gel coating technology additionally provided the porous structure of the 3-D silica network and the strong chemical binding provided which also will improve the extraction efficiency. Under optimized conditions, the method detection limits for seven PBDEs were 0.08-0.8 ng/L (S/N = 3) and the precision (RSD, n = 5) was 2.2-7.5% at the 50 ng/L level. The linearity of the developed method is in the range of 5-500 ng/L with coefficients of correlation greater than 0.995. The developed method was successfully applied for the analysis of trace PBDEs in reservoir water and wastewater samples. The recoveries obtained at spiking 50 ng/L were between 74% and 109% (n = 5) for PBDEs in water samples. PMID:19364140

Zhang, Weiya; Sun, Yin; Wu, Caiying; Xing, Jun; Li, Jianying

2009-04-15

24

Impacts of gas drilling on human and animal health.  

PubMed

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

Bamberger, Michelle; Oswald, Robert E

2012-01-01

25

The greenhouse impact of unconventional gas for electricity generation  

NASA Astrophysics Data System (ADS)

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.

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

2011-10-01

26

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...

27

Pennsylvania Energy Impacts Assessment Report 1: Marcellus Shale Natural Gas and Wind  

E-print Network

Pennsylvania Energy Impacts Assessment Report 1: Marcellus Shale Natural Gas and Wind #12;1 Pennsylvania Energy Impacts Assessment Report 1: Marcellus Shale Natural Gas and Wind November 15, 2010 Author.....................................................................................................................3 Marcellus Shale Natural Gas

Boyer, Elizabeth W.

28

ORIGINAL PAPER Impacts of ocean acidification on respiratory gas exchange  

E-print Network

ORIGINAL PAPER Impacts of ocean acidification on respiratory gas exchange and acid­base balance; Orr et al. 2005). Consequently, the effects of ocean acidification on these organisms have been). These unprecedented changes in the marine environment pose potentially dramatic challenges for marine organisms

Grosell, Martin

29

Impact of greenhouse gas emissions reduction in Indonesia: NO2  

NASA Astrophysics Data System (ADS)

In this study, we develop scenarios of total air pollution from fossil fuel consumption and its impacts for the 21st century, using an inter-temporal general equilibrium model MERGE. The Model for Evaluating the Regional and Global Effects of greenhouse gas reduction policies (MERGE) is used to project energy consumption and production. We use the base scenarios from IPCC (2000). These scenarios assume that no measures are undertaken to control greenhouse gas emissions. We extend the IPCC scenarios with mitigation scenarios, estimating the air pollution impacts of greenhouse gas emission reduction. The MERGE model was extended to analyze emissions of nitrogen dioxide (NO2), their concentrations, impacts on human health, and economic valuation. To estimate of nitrogen dioxide (NO2) impacts on respiratory symptoms, we calculated the NO2 concentration as derived from nitrogen oxide (NOx). In the baseline scenario, the concentrations of NO2 are rising to 2,263 ?g/m3 in 2100. If the Organisation for Economic Co-operation and Development (OECD) countries reduce their emissions, respiratory symptoms among adult's associated with NO2 case would reach the highest to 65,741% of adult population cases by the end of century. If all countries reduce their emission in the future, the total health problem cost associated with NO2 will lower 35% of GDP than in the baseline scenario during the century.

Susandi, A.

2004-12-01

30

Summary of Oil and Natural Gas Development Impacts on Prairie Grouse September 2006  

E-print Network

Summary of Oil and Natural Gas Development Impacts on Prairie Grouse September 2006 Jeffrey L. Beck development impacts on prairie grouse. Unpublished Report, Colorado Division of Wildlife, Grand Junction and Natural Gas Development Impacts on Prairie Grouse 2 disturbances such as oil and gas development

Beck, Jeffrey L.

31

NBER WORKING PAPER SERIES THE HOUSING MARKET IMPACTS OF SHALE GAS DEVELOPMENT  

E-print Network

NBER WORKING PAPER SERIES THE HOUSING MARKET IMPACTS OF SHALE GAS DEVELOPMENT Lucija Muehlenbachs © notice, is given to the source. #12;The Housing Market Impacts of Shale Gas Development Lucija to control for confounding factors, we recover hedonic estimates of property value impacts from shale gas

Habib, Ayman

32

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

PubMed

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

Allen, David T

2014-01-01

33

Impact Studies Using a One Stage Light Gas Gun  

E-print Network

The Center for Astrophysics,Space Physics, and Engineering Research (CASPER) has completed construction and calibration of a Light Gas Gun (LGG), which is used for low velocity impact studies. At geosynchronous orbit, space debris can impact commercial satellites at velocities of 500 m/s [1] reducing their useful lifetime. Additionally, there is an ever-increasing population of abandoned nonoperational satellites and related debris in these orbits [2]. Therefore, it is important to clearly understand the physics behind how such collisions can cause structural damage. This is most easily determined by measuring the damage incurred on representative material exposed to test collisions in the laboratory. Data collected in this manner will not only help illuminate the shock physics involved but can also aid in providing methods for designing advanced shielding for satellites.

Jorge Carmona; Mike Cook; Jimmy Schmoke; Katie Harper; Jerry Reay; Lorin Matthews; Truell Hyde

2004-01-29

34

Private Water Well Testing in Areas Impacted by Marcellus Shale Gas Drilling  

E-print Network

Private Water Well Testing in Areas Impacted by Marcellus Shale Gas Drilling (Updated November 15th in the absence of shale-gas drilling, well owners are strongly encouraged to evaluate their water on a regular testing in order to more specifically document potential impacts of Marcellus Shale gas development

Manning, Sturt

35

Craters on silicon surfaces created by gas cluster ion impacts L. P. Allena)  

E-print Network

Craters on silicon surfaces created by gas cluster ion impacts L. P. Allena) Epion Corporation, 37 HRTEM cross section imaging of individual gas cluster ion impact craters on Si 100 and Si 111 substrate. The lower energy 3 kV individual cluster impacts reveal the same crater shape in HRTEM cross section

Florida, University of

36

Ozone impacts of natural gas development in the Haynesville Shale.  

PubMed

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

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

2010-12-15

37

Impacts of Shale Gas Wastewater Disposal on Water Quality in Western Pennsylvania  

E-print Network

Impacts of Shale Gas Wastewater Disposal on Water Quality in Western Pennsylvania Nathaniel R bioaccumulation in localized areas of shale gas wastewater disposal. INTRODUCTION The safe disposal of large States, oil and gas wastewater is managed through recycling of the wastewater for shale gas operations

Jackson, Robert B.

38

Atmospheric Impacts of Marcellus Shale Gas Activities in Southwestern Pennsylvania  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

39

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

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF AGRICULTURE Forest Service White River National Forest, Colorado, Oil and Gas Leasing Environmental Impact Statement AGENCY: Forest Service, USDA. ACTION: Notice of intent to prepare an...

2010-06-30

40

Postulated impact craters yield oil and gas, lively debate  

SciTech Connect

Impact craters, also called astroblemes, are the most common landform in the solar system, and several on earth have produced oil and gas. Significant cross-disciplinary study is being aimed at understanding the origin, structure, and economic potential of surface and buried craters worldwide. The Oklahoma Geological Survey and the US Department of Energy organized a workshop to discuss the Ames structure, a feature in Major Country, Okla., along the sprawling, giant Sooner Trend/Ringwood oil producing complex. This rundown is designed to provide basic information gleaned from speakers and abstracts presented at the workshop. OGS is to publish proceedings later. This paper discusses meteors vs. volcanoes, the Oklahoma crater, questions about Ames, producing astroblemes, and future research.

Petzet, G.A.

1995-04-10

41

IMPACTS OF OIL AND NATURAL GAS ON PRAIRIE GROUSE: CURRENT KNOWLEDGE AND RESEARCH NEEDS1  

E-print Network

IMPACTS OF OIL AND NATURAL GAS ON PRAIRIE GROUSE: CURRENT KNOWLEDGE AND RESEARCH NEEDS1 Jeffrey L. Beck2 Abstract. The direct and indirect impacts of energy development on prairie grouse have been and natural gas development on grouse populations and habitats. The purpose of this review is to summarize

Beck, Jeffrey L.

42

The Role of Isotopes in Monitoring Water Quality Impacts Associated with Shale Gas Drilling  

E-print Network

The Role of Isotopes in Monitoring Water Quality Impacts Associated with Shale Gas Drilling Methane, including shale gas drilling. Monitoring techniques exist for detecting methane and, in some cases detail within the context of shale gas drilling activities in New York, as well as their uses

Wang, Z. Jane

43

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

PubMed

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

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

2014-08-01

44

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 ...

45

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

USGS Publications Warehouse

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)

Pattison, Malka L.

1977-01-01

46

Impacts of winter storms on air-sea gas exchange  

NASA Astrophysics Data System (ADS)

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 (50°N, 145°W). 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.

Zhang, Weiqing; Perrie, Will; Vagle, Svein

2006-07-01

47

Shale gas development impacts on surface water quality in Pennsylvania  

PubMed Central

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

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

2013-01-01

48

Shale gas development impacts on surface water quality in Pennsylvania.  

PubMed

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

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

2013-03-26

49

The aroma development during storage of Castlebrite apricots as evaluated by gas chromatography, electronic nose, and sensory analysis  

Microsoft Academic Search

One of the most important factors limiting apricot quality is the loss of flavor during storage, particularly overall aroma. To characterize fruit aroma, several techniques have been used, including both instrumental- and sensory-based methodologies. Despite the importance of aroma in fruit quality, limited information is available regarding the effects of long-term cold storage and ripening on the apricot’s volatile compound

B. G. Defilippi; H. Valdés; M. A. Moya-León; R. Infante; R. Campos-Vargas

2009-01-01

50

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

SciTech Connect

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).

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

1994-12-01

51

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

SciTech Connect

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}.

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

1993-12-01

52

Embryo impacts and gas giant mergers II: Diversity of Hot Jupiters' internal structure  

E-print Network

We consider the origin of compact, short-period, Jupiter-mass planets. We propose that their diverse structure is caused by giant impacts of embryos and super-Earths or mergers with other gas giants during the formation and evolution of these hot Jupiters. Through a series of numerical simulations, we show that typical head-on collisions generally lead to total coalescence of impinging gas giants. Although extremely energetic collisions can disintegrate the envelope of gas giants, these events seldom occur. During oblique and moderately energetic collisions, the merger products retain higher fraction of the colliders' cores than their envelopes. They can also deposit considerable amount of spin angular momentum to the gas giants and desynchronize their spins from their orbital mean motion. We find that the oblateness of gas giants can be used to infer the impact history. Subsequent dissipation of stellar tide inside the planets' envelope can lead to runaway inflation and potentially a substantial loss of gas ...

Liu, Shang-Fei; Lin, D N C; Li, Shu-Lin

2014-01-01

53

Volcanic gas impacts on vegetation at Turrialba Volcano, Costa Rica  

NASA Astrophysics Data System (ADS)

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.

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

2010-12-01

54

Oil and Gas Innovation call June 2014 Reference PI Institution Title Impact  

E-print Network

Oil and Gas Innovation call June 2014 Reference PI Institution Title Impact Score Fit score Rank NE to petrophysical models for shale gas reservoirs based on sensitivity analysis of key variables 7 5 2 NE/M007235 of Manchester CASCADE - UK Carboniferous Shale Resource Assessment, Characterization and Development Evaluation

55

Impact of Gas Heating in Inductively Coupled Plasmas  

NASA Technical Reports Server (NTRS)

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.

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

56

Modeling Impacts of Management on Carbon Sequestration and Trace Gas Emissions in Forested  

E-print Network

Modeling Impacts of Management on Carbon Sequestration and Trace Gas Emissions in Forested Wetland-DNDC, was modified to enhance its capacity to predict the impacts of management practices on carbon sequestration nonnegligible roles in mitigation in comparison with carbon sequestration. Forests are recognized for having

57

2007-No54-BoilingPoint Health and Greenhouse Gas Impacts of Biomass and Fossil Fuel  

E-print Network

2007-No54-BoilingPoint Theme Health and Greenhouse Gas Impacts of Biomass and Fossil Fuel Energy of fossil-fuel energy systems. These scenarios are analysed for various environmental and health impacts from fossil fuels and other energy sources reported by IEA []. In all of these countries except Kenya

Kammen, Daniel M.

58

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

PubMed

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

Jones, Nathan F; Pejchar, Liba

2013-01-01

59

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

PubMed Central

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

Jones, Nathan F.; Pejchar, Liba

2013-01-01

60

Impacts of greenhouse gas mitigation policies on agricultural land  

E-print Network

Greenhouse gas (GHG) emissions are widely acknowledged to be responsible for much of the global warming in the past century. A number of approaches have been proposed to mitigate GHG emissions. Since the burning of ...

Wang, Xiaodong, Ph. D. Massachusetts Institute of Technology

2008-01-01

61

Impact of shale gas development on regional water quality.  

PubMed

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

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

2013-05-17

62

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...

63

The impacts of technology on global unconventional gas supply  

E-print Network

in increasing unconventional natural gas production, as observed in the United States, Canada, and Australia. 3D seismic, horizontal drilling, multilateral completion, water and gel based fracturing, coiled tubing rig, enhanced recovery, and produced water...

Yanty, Evi

2009-06-02

64

Embryo impacts and gas giant mergers - II. Diversity of hot Jupiters' internal structure  

NASA Astrophysics Data System (ADS)

We consider the origin of compact, short-period, Jupiter-mass planets. We propose that their diverse structure is caused by giant impacts of embryos and super-Earths or mergers with other gas giants during the formation and evolution of these hot Jupiters. Through a series of numerical simulations, we show that typical head-on collisions generally lead to total coalescence of impinging gas giants. Although extremely energetic collisions can disintegrate the envelope of gas giants, these events seldom occur. During oblique and moderately energetic collisions, the merger products retain higher fraction of the colliders' cores than their envelopes. They can also deposit considerable amount of spin angular momentum to the gas giants and desynchronize their spins from their orbital mean motion. We find that the oblateness of gas giants can be used to infer the impact history. Subsequent dissipation of stellar tide inside the planets' envelope can lead to runaway inflation and potentially a substantial loss of gas through Roche lobe overflow. The impact of super-Earths on parabolic orbits can also enlarge gas giant planets' envelope and elevates their tidal dissipation rate over ˜100 Myr time scale. Since giant impacts occur stochastically with a range of impactor sizes and energies, their diverse outcomes may account for the dispersion in the mass-radius relationship of hot Jupiters.

Liu, Shang-Fei; Agnor, Craig B.; Lin, D. N. C.; Li, Shu-Lin

2015-01-01

65

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

...Environmental Impact Statement for the Gas Hills Uranium Project, Fremont and Natrona Counties...Environmental Impact Statement for the Gas Hills Uranium Project, Fremont and Natrona Counties...legal land description for the Gas Hills Uranium Project location is as follows:...

2010-11-04

66

The impact of corrosion on the oil and gas industry  

SciTech Connect

The impact of corrosion on the oil industry has been viewed in terms of its effect on both capital and operational expenditures (CAPEX and OPEX) and health, safety, and the environment (HSE). To fight against the high cost and the impact of corrosion within the oil industry, an overview of topical research and engineering activities is presented. This covers corrosion and metallurgy issues related to drilling, production, transportation, and refinery activities.

Kermani, M.B.; Harrop, D.

1996-08-01

67

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

SciTech Connect

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.

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

2009-12-09

68

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

PubMed

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

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

69

Novel glycosylation sites localized in Campylobacter jejuni flagellin FlaA by liquid chromatography electron capture dissociation tandem mass spectrometry.  

PubMed

Glycosylation of flagellin in Campylobacter jejuni is essential for motility and virulence. It is well-known that flagellin from C. jejuni 81-176 is glycosylated by pseudaminic acid and its acetamidino derivative, and that Campylobactor coli VC167 flagellin is glycosylated by legionaminic acid and its derivatives. Recently, it was shown, by use of a metabolomics approach, that C. jejuni 11168 is glycosylated by dimethyl glyceric acid derivatives of pseudaminic acid, but the sites of glycosylation were not confirmed. Here, we apply an online liquid chromatography electron capture dissociation (ECD) tandem mass spectrometry approach to localize sites of glycosylation in flagellin from C. jejuni 11168. Flagellin A is glycosylated by a dimethyl glyceric acid derivative of pseudaminic acid at Ser181, Ser207 and either Thr464 or Thr 465; and by a dimethyl glyceric acid derivative of acetamidino pseudaminic acid at Ser181 and Ser207. For comparison, on-line liquid chromatography collision-induced dissociation of the tryptic digests was performed, but it was not possible to assign sites of glycosylation by that method. PMID:21158479

Zampronio, Cleidiane G; Blackwell, Gemma; Penn, Charles W; Cooper, Helen J

2011-03-01

70

Wellbeing Impacts of City Policies for Reducing Greenhouse Gas Emissions  

PubMed Central

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

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

2014-01-01

71

Wellbeing impacts of city policies for reducing greenhouse gas emissions.  

PubMed

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

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

2014-12-01

72

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

NASA Astrophysics Data System (ADS)

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.

Post, David

2014-05-01

73

The impact of ice layers on gas transport through firn  

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

74

75 FR 54384 - Notice of Intent To Prepare an Environmental Impact Statement for the Gas Hills Uranium Project...  

Federal Register 2010, 2011, 2012, 2013

...Environmental Impact Statement for the Gas Hills Uranium Project, Fremont and Natrona Counties...proposed Gas Hills in situ recovery (ISR) Uranium Project (the Project), Fremont County...Natrona County, Wyoming. The project is a uranium exploration and development...

2010-09-07

75

Impact of Sorption Isotherms on the Simulation of CO2-Enhanced Gas Recovery and Storage Process in Marcellus Shale  

E-print Network

Continuous, low-permeability, fractured, organic-rich gas shale units are widespread and are possible, organic-rich rocks that are both the source and trap for natural gas (primarily methane). In shale gas1 Impact of Sorption Isotherms on the Simulation of CO2-Enhanced Gas Recovery and Storage Process

Mohaghegh, Shahab

76

Impact of Airway Gas Exchange on the Multiple Inert Gas Elimination Technique: Theory  

PubMed Central

The multiple inert gas elimination technique (MIGET) provides a method for estimating alveolar gas exchange efficiency. Six soluble inert gases are infused into a peripheral vein. Measurements of these gases in breath, arterial blood, and venous blood are interpreted using a mathematical model of alveolar gas exchange (MIGET model) that neglects airway gas exchange. A mathematical model describing airway and alveolar gas exchange predicts that two of these gases, ether and acetone, exchange primarily within the airways. To determine the effect of airway gas exchange on the MIGET, we selected two additional gases, toluene and m-dichlorobenzene, that have the same blood solubility as ether and acetone and minimize airway gas exchange via their low water solubility. The airway-alveolar gas exchange model simulated the exchange of toluene, m-dichlorobenzene, and the six MIGET gases under multiple conditions of alveolar ventilation-to-perfusion, V?A/Q?, heterogeneity. We increased the importance of airway gas exchange by changing bronchial blood flow, Q?br. From these simulations, we calculated the excretion and retention of the eight inert gases and divided the results into two groups: 1) the standard MIGET gases which included acetone and ether and 2) the modified MIGET gases which included toluene and m-dichlorobenzene. The MIGET mathematical model predicted distributions of ventilation and perfusion for each grouping of gases and multiple perturbations of V?A/Q? and Q?br. Using the modified MIGET gases, MIGET predicted a smaller dead space fraction, greater mean V?A, greater log(SDVA), and more closely matched the imposed V?A distribution than that using the standard MIGET gases. Perfusion distributions were relatively unaffected. PMID:20336837

Anderson, Joseph C.; Hlastala, Michael P.

2011-01-01

77

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

NASA Astrophysics Data System (ADS)

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.

Swarthout, Robert F.

78

Solar-Type Eclipsing Binary Systems with Impacting Gas Streams  

NASA Astrophysics Data System (ADS)

Our quest is the recovery of near contact solar type eclipsing binaries with evidence for stream impacts. Their existence will provide strong support of dynamic mass transfer leading to coalescence into a state of contact. This will lend strong support to the theoretical scenarios of 1) angular momentum loss(AML)via magnetic breaking scenario and 2)Thermal Relaxation Oscillations (TRO)or oscillations between a near­contact and shallow contact modes. We hypothesize that many F to early K spectral type binaries formerly classified as ''thermally decoupled'' contact binaries and other binaries with large differences in eclipse depths formerly classified as contact binaries in the 0.33 to 0.5d period range will reveal evidence for stream impacts when they are subjected to precision UBVRI multi­band photometry, since these fall in the pre­contact period range for F to K dwarf binaries. Modern light curve synthesis techniques will be used to simultaneously model the multi­band light curves. Impact spots will be adjusted numerically along with the stellar atmosphere parameters. Spectroscopic work will follow to verify stream activity and to obtain fundamental physical characteristics. Our larger goal is to understand close binary evolution in general. This study could supply an important piece to the puzzle. We now have found four candidates, CN And, BE Cep, ZZ Eri and V343 Cen giving us an encouraging 40 percent recovery thus far.

Samec, Ronald G.; Hube, Doug; Faulkner, Danny R.; van Hamme, W.

2002-08-01

79

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

PubMed Central

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

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

2009-01-01

80

Impact of numerical integration on gas curtain simulations  

SciTech Connect

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.

Rider, W.; Kamm, J.

2000-11-01

81

Impact of compressed natural gas fueled buses on street pavements  

SciTech Connect

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.

Yang, D.; Harrison, R.

1995-07-01

82

Gas desorption and up-scaling errors in CBM groundwater impact simulations  

NASA Astrophysics Data System (ADS)

Coalbed Methane (CBM) is a major energy resource in Australia. Production of CBM requires the extraction of large amounts of groundwater to enable gas desorption from the coalbeds. As CBM raises concerns regarding its impact on adjacent aquifer systems, groundwater models are often required for groundwater impact assessment. Questions arise about the suitability of traditional groundwater flow simulators for CBM groundwater impact quantification as 1) the gas phase is not simulated and 2) up-scaled properties are used that might not reflect coalbed properties appropriately. First, this study aims to quantify the errors incurred by neglecting gas desorption by comparing a CBM reservoir simulator (Eclipse) with an equivalent groundwater flow model (MODFLOW-USG) for a single 1m coal seam. Simulations show the groundwater model significantly overestimates drawdowns during the CBM production stage, as the desorbed gas volume is not accounted for, which impacts storage and the relative permeability of water that are assumed to be constant in the groundwater model. To improve the match between the groundwater model and CBM reservoir simulations, MODFLOW-USG was configured to implement a relationship that was obtained using a pseudo steady-state relationship between drawdown and desaturation derived from Eclipse simulations. A second set of simulations for a sequence of coalbeds was performed to quantify the impact of up-scaling on predicting drawdowns and to validate whether relative permeability curves in the CBM reservoir simulator still have integrity in an up-scaled context. These simulations will help understand how physically representative different up-scaled models are, what errors could be made when regional groundwater modelling is undertaken in a CBM environment and ultimately help decide whether a groundwater flow simulator can be used for CBM groundwater impact assessments. Key words: Coalbed Methane, Up-scaling, Reservoir model, Groundwater model, Dual-phase flow, Gas desorption, MODFLOW, Eclipse

Herckenrath, D.; Doherty, J.

2013-12-01

83

Solar-Type Binary Systems with Impacting Gas Streams  

NASA Astrophysics Data System (ADS)

We hypothesize that many F to early K spectral type binaries formerly classified as "thermally decoupled" (Maceroni and Van 'TVeer 1990) contact binaries will reveal stream impacts when they are subjected to precision UBVRI multi-band photometry. Other near contact binaries with large differences in eclipse depths formerly classified as contact binaries in the 0.5 to 0.33d period range will also be found in this configuration, since these fall in the pre-contact period range for F-K dwarf binaries. In this preliminary part of our study, we plan to obtain precision light curves of 20-25 likely candidates. Modern light curve synthesis techniques will be used to simultaneously model the multi-band light curves. Impact spots will be adjusted numerically within our models along with other astrophysical stellar atmosphere parameters. After this preliminary photometry, follow-up spectroscopic work will be done in the visible, UV and IR follow-up work will be done in the visible and in UV and IR to verify stream activity in emission lines. Our goal is to confirm the detached-to-contact scenario suggested by Guinan and Bradstreet. Our larger goal is to understand close binary evolution in general, in detached, semidetached and contact modes. This study could supply an important piece to the puzzle.

Samec, Ronald G.; Hube, Doug; Faulkner, Danny R.

1999-08-01

84

Impact of relative permeability models on fluid flow behavior for gas condensate reservoirs  

E-print Network

and on the quantification of their impact on reservoir fluid flow and well performance. We selected three relative permeability models to compare the results obtained in the modeling of relative permeabilities for a published North Sea gas condensate reservoir. The models...

Zapata Arango, Jose? Francisco

2012-06-07

85

Project 35013 Species-and Site-specific Impacts of Gas Supersaturation on Aquatic Animals  

E-print Network

, dynamic interactions of diverse species and healthy habitats within which they can persist. By examiningProject 35013 Species- and Site-specific Impacts of Gas Supersaturation on Aquatic Animals Sponsor three species tend to be bottom oriented and deep water species, and most TDG effects are in the upper

86

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...

87

TECHNICAL REPORTS The greenhouse gas (GHG) impact of composting a range  

E-print Network

TECHNICAL REPORTS 1396 The greenhouse gas (GHG) impact of composting a range of potential by composting and GHG emissions during composting. The primary carbon credits associated with composting are through CH4 avoidance when feedstocks are composted instead of landfilled (municipal solid waste

Brown, Sally

88

Mineralogical and Noble Gas Evidence for an ET Impact at the Younger Dryas  

Microsoft Academic Search

We report mineralogical and noble gas evidence for an ET impact associated with the Younger Dryas (YD) event and the mass extinction of various megafauna throughout the Americas approximately 12,900 years ago. We examined numerous well established, 14C dated Clovis sites across the US including detailed sediment profile analyses at Daisy Cave, CA (DC), Murray Springs, AZ (MS), Topper, SC,

T. H. Darrah; R. J. Poreda; J. P. Kennett; L. Becker; D. J. Kennett; J. M. Erlandson

2006-01-01

89

Mineralogical and Noble Gas Evidence for an ET Impact at the Younger Dryas  

Microsoft Academic Search

We report mineralogical and noble gas evidence for an ET impact associated with the Younger Dryas (YD) event and the mass extinction of various megafauna throughout the Americas approximately 12,900 years ago. We examined numerous well established, 14C dated Clovis sites across the US including detailed sediment profile analyses at Daisy Cave, CA (DC), Murray Springs, AZ (MS), Topper, SC,

T. H. Darrah; R. J. Poreda; J. P. Kennett; L. Becker; D. J. Kennett; J. M. Elrandson

2007-01-01

90

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...

91

Livestock-related greenhouse gas emissions: impacts and options for policy makers  

Microsoft Academic Search

Research shows that livestock account for a significant proportion of greenhouse gas (GHG) emissions and global consumption of livestock products is growing rapidly. This paper reviews the life cycle analysis (LCA) approach to quantifying these emissions and argues that, given the dynamic complexity of our food system, it offers a limited understanding of livestock's GHG impacts. It is argued that

Tara Garnett

2009-01-01

92

ENERGETIC INERT GAS ATOM IMPACT EFFECTS DURING ION BEAM MULTILAYER DEPOSITION  

E-print Network

that hyperthermal metal atoms created by sputtering processes such as RF diode (or magnetron) sputtering and ion,6]. This is consistent with other observations that magnetron sputtering gives rise to the best GMR multilayers under. During ion beam sputtering, inert gas neutrals with energies between 50 and 200 eV impact the growth

Wadley, Haydn

93

HumanWildlife Interactions 8(2):284290, Fall 2014 Oil and gas impacts on Wyoming's sage-  

E-print Network

Human­Wildlife Interactions 8(2):284­290, Fall 2014 Oil and gas impacts on Wyoming's sage- grouse: Historical impacts from oil and gas development to greater sage-grouse (Centrocercus urophasianus) habitat) warranted- but-precluded listing determination for the sage-grouse under the Endangered Species Act. Further

94

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

PubMed Central

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

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

2015-01-01

95

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

PubMed

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

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

2015-02-01

96

Regional Variation in Water-Related Impacts of Shale Gas Development and Implications for Emerging International Plays  

E-print Network

Regional Variation in Water-Related Impacts of Shale Gas Development and Implications for Emerging 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

Alvarez, Pedro J.

97

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

PubMed

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

Steinzor, Nadia; Subra, Wilma; Sumi, Lisa

2013-01-01

98

Impacts of Marcellus Shale Natural Gas Production on Regional Air Quality  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

99

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

PubMed

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

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

2014-02-01

100

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

PubMed

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

Barth, Jannette M

2013-01-01

101

Quantifying habitat impacts of natural gas infrastructure to facilitate biodiversity offsetting  

PubMed Central

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

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

2014-01-01

102

Experimental study on the impact of temperature on the dissipation process of supersaturated total dissolved gas.  

PubMed

Water temperature not only affects the solubility of gas in water but can also be an important factor in the dissipation process of supersaturated total dissolved gas (TDG). The quantitative relationship between the dissipation process and temperature has not been previously described. This relationship affects the accurate evaluation of the dissipation process and the subsequent biological effects. This article experimentally investigates the impact of temperature on supersaturated TDG dissipation in static and turbulent conditions. The results show that the supersaturated TDG dissipation coefficient increases with the temperature and turbulence intensity. The quantitative relationship was verified by straight flume experiments. This study enhances our understanding of the dissipation of supersaturated TDG. Furthermore, it provides a scientific foundation for the accurate prediction of the dissipation process of supersaturated TDG in the downstream area and the negative impacts of high dam projects on aquatic ecosystems. PMID:25193837

Shen, Xia; Liu, Shengyun; Li, Ran; Ou, Yangming

2014-09-01

103

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

Microsoft Academic Search

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 72×0.1 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

D. R. Currie; Leanne R. Isaacs

2005-01-01

104

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

SciTech Connect

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.

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

2007-04-01

105

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

SciTech Connect

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.

Li Shulin [Department of Astronomy, Kavli Institute of Astronomy and Astrophysics, Peking University, Beijing (China); Agnor, C.B. [Astronomy Unit, School of Mathematical Sciences, Queen Mary University of London (United Kingdom); Lin, D. N. C. [Department of Astronomy and Astrophysics, University of California Santa Cruz (United States)

2010-09-10

106

Estimating the Impact of US Agriculture Subsidies on Greenhouse Gas Emissions  

NASA Astrophysics Data System (ADS)

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.

Eshel, G.; Martin, P. A.

2006-12-01

107

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

NASA Astrophysics Data System (ADS)

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.

Allen, D.; Pacsi, A. P.

2013-12-01

108

The Impact of Measurement Noise in GPA Diagnostic Analysis of a Gas Turbine Engine  

NASA Astrophysics Data System (ADS)

The performance diagnostic analysis of a gas turbine is accomplished by estimating a set of internal engine health parameters from available sensor measurements. No physical measuring instruments however can ever completely eliminate the presence of measurement uncertainties. Sensor measurements are often distorted by noise and bias leading to inaccurate estimation results. This paper explores the impact of measurement noise on Gas Turbine GPA analysis. The analysis is demonstrated with a test case where gas turbine performance simulation and diagnostics code TURBOMATCH is used to build a performance model of a model engine similar to Rolls-Royce Trent 500 turbofan engine, and carry out the diagnostic analysis with the presence of different levels of measurement noise. Conclusively, to improve the reliability of the diagnostic results, a statistical analysis of the data scattering caused by sensor uncertainties is made. The diagnostic tool used to deal with the statistical analysis of measurement noise impact is a model-based method utilizing a non-linear GPA.

Ntantis, Efstratios L.; Li, Y. G.

2013-12-01

109

Strategic petroleum reserve and liquefied natural gas supplies. Final report. [Impact of LNG and\\/or oil embargo  

Microsoft Academic Search

The United States is planning to import liquefied natural gas (LNG) to offset the effects of our apparent dwindling natural gas supply. These imports would begin by the 1980s and would come from Algeria, Indonesia, Pakistan, Iran, Nigeria, and possibly the Soviet Union. If a disruption in LNG supplies were to occur, the impact to the nation could be eased

R. J. Fink; B. A. Bancroft; T. M. Palmieri

1977-01-01

110

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

NASA Astrophysics Data System (ADS)

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

Chang, C.; Liao, K.

2013-12-01

111

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

PubMed

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

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

2009-09-01

112

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

NASA Astrophysics Data System (ADS)

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.

Baxter, Peter J.; Kapila, Mukesh

1989-11-01

113

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

PubMed

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

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

2014-08-01

114

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

115

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

NASA Astrophysics Data System (ADS)

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.

Telichev, Igor; Cherniaev, Aleksandr

116

Semi-analytical models of hydroelastic sloshing impact in tanks of liquefied natural gas vessels.  

PubMed

The present paper deals with the methods for the evaluation of the hydroelastic interactions that appear during the violent sloshing impacts inside the tanks of liquefied natural gas carriers. The complexity of both the fluid flow and the structural behaviour (containment system and ship structure) does not allow for a fully consistent direct approach according to the present state of the art. Several simplifications are thus necessary in order to isolate the most dominant physical aspects and to treat them properly. In this paper, choice was made of semi-analytical modelling for the hydrodynamic part and finite-element modelling for the structural part. Depending on the impact type, different hydrodynamic models are proposed, and the basic principles of hydroelastic coupling are clearly described and validated with respect to the accuracy and convergence of the numerical results. PMID:21690141

Ten, I; Malenica, Š; Korobkin, A

2011-07-28

117

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

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

118

Impact of fly ash composition on mercury speciation in simulated flue gas.  

PubMed

The impact of different fly ash samples on mercury speciation in simulated flue gas at 140 degrees C was evaluated in this study. Experiments were conducted in a fixed bed reactor to determine the impact of fly ash morphological characteristics and chemical composition on mercury uptake and oxidation. No homogeneous mercury oxidation was observed at 140 degrees C. Mercury uptake tests with different fly ash samples revealed that loss on ignition (LOI), surface area, and particle size all had positive effects on mercury oxidation and adsorption (i.e., as the above parameters increased, mercury adsorption and oxidation also increased). Experiments with pure inorganic components showed that alumina (A12O3), silica (SiO2), calcium oxide (CaO), magnesium oxide (MgO), and titania (TiO2) do not promote mercury oxidation or adsorption. Ferric oxide (Fe2O3) and unburned carbon, on the other hand, showed significant mercury oxidation and capture. PMID:19947114

Bhardwaj, Ravi; Chen, Xihua; Vidic, Radisav D

2009-11-01

119

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

SciTech Connect

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.

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

120

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

PubMed

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

Ulvestad, Marte; Overland, Indra

2012-06-01

121

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

PubMed Central

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

Ulvestad, Marte; Overland, Indra

2012-01-01

122

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

SciTech Connect

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.

Sulfredge, Charles David [ORNL

2007-07-01

123

Application of flue gas desulfurization gypsum and its impact on wheat grain and soil chemistry.  

PubMed

The 11 major electricity-generating coal combustion stations in the northern Great Plains have the potential to produce almost 1 million Mg of flue gas desulfurization gypsum (FGDG) annually, which is a very attractive fertilizer (Ca and S) and amendment for sodic and acid soils. The potential environmental impacts of applying FGDG to soils in this region have not been fully investigated. The objectives of this research were to determine the influence of FGDG on soil chemical characteristics and to determine the impact that FGDG has on hard red spring wheat ( L.) yields and element analysis of the grain. Flue gas desulfurization gypsum and commercial gypsum were applied at rates of 0, 2.24, 11.2, and 22.4 Mg ha to two soils in southwestern North Dakota in the spring of 2007. Soil and grain chemistries were monitored for two growing seasons. Wheat grain yields and elemental analysis of the grain were generally not affected by the gypsum treatments, indicating that the gypsum products did not negatively affect plant productivity. In addition, soil elemental analysis was similar across the treatments at both sites in both years. The results from this study indicate that its application to soil at rates used for sodic soil remediation (Mg ha) did not negatively affect the chemistries of either the soils or the wheat evaluated in this study compared with a commercial gypsum product or control soils. PMID:25602564

DeSutter, T M; Cihacek, L J; Rahman, S

2014-01-01

124

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

NASA Astrophysics Data System (ADS)

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.

Mac Kinnon, Michael

125

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

NASA Technical Reports Server (NTRS)

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.

Ngo, Khiem Viet; Tumer, Irem

2004-01-01

126

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

SciTech Connect

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.

Kirschner, C.E.; Grantz, A. (Geological Survey, Menlo Park, CA (USA))

1990-05-01

127

Lyman Alpha Mapping Project (LAMP) Detections of LCROSS Impact Plume Gas  

NASA Astrophysics Data System (ADS)

The Lyman Alpha Mapping Project (LAMP) is an ultraviolet (UV) spectrograph on the Lunar Reconnaissance Orbiter (LRO) that is designed to map the lunar albedo at far-UV wavelengths. LAMP's spectral range of 57.5 nm to 196.5 nm includes emission line features from several known and expected lunar atmosphere constituents, including resonantly scattered Lyman-alpha (121.57 nm) emissions from hydrogen atoms and argon atom emissions at 104.82 nm and 106.67 nm. The LCROSS impact on 9 October 2009 elevated and exposed water ice and other volatiles trapped near the lunar surface (Colaprete et al., submitted, 2010). Observations with LRO/LAMP detected enhancements of volatile species in the plume shortly after impact (Gladstone et al., submitted, 2009). The plume of rapidly expanding gas includes molecular hydrogen gas seen by sunlit fluorescence. Resonantly scattered emissions from atomic Hg, Mg, and Ca in sunlight are also likely detected in a feature near 185 nm. The molecular hydrogen content within permanently shadowed regions (PSRs) is higher than possible through dissociation of water alone, which indicates that trapped hydrogen gas likely contributes to the hydrogen content of the PSRs in addition to the water detected there. The concentration of mercury in PSRs has implications for future exploration and in situ resource utilization in these regions. This investigation addresses how water and other volatiles arrive (or form) at the lunar surface, are transported through the lunar atmosphere, and are deposited within PSRs (or elsewhere), which is closely related to LAMP's primary objectives.

Retherford, Kurt; Gladstone, Randy; Stern, Alan; Hurley, Dana; Feldman, Paul; Pryor, Wayne; Hendrix, Amanda; Goldstein, David; Summy, Dustin

2010-05-01

128

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

129

Impact facility based upon high frequency two-stage light-gas gun  

NASA Astrophysics Data System (ADS)

An impact facility based upon a two-stage high-frequency light-gas gun has been developed to allow fast and low-cost hypervelocity tests. The mechanical configuration and the managing electronic system are presented. The unit is powered only by means of high-pressure gas: no explosive powder is used. The system is managed by a dedicated computer system, which acquires signals from pressure transducers and operates nine electron valves. To improve the gun reliability, the control system has been designed to carry out an automatic diagnostic procedure after each shot. To improve the gun performance and the safety, an active piston-damping procedure has been developed. In this configuration a high shot frequency has been reached (10 shots/h) . Projectiles with mass between 100- 300 mg have been launched up to 3- 4 km/s depending on the mass. This work can also be seen as a feasibility study for a new class of high-performance, high-frequency and low-cost two-stage light-gas guns, useful for the Italian Hypervelocity Laboratory, proposed to be built at the Italian Center for Aerospatial Research (CIRA).

Angrilli, F.; Pavarin, D.; De Cecco, M.; Francesconi, A.

2003-08-01

130

Speaker to Address Impact of Natural Gas Production on Greenhouse Gas Emissions When used for power generation, Marcellus Shale natural gas can significantly reduce carbon  

E-print Network

generation, Marcellus Shale natural gas can significantly reduce carbon dioxide emissions, but questions have been raised whether development of shale gas resources results in an overall lower greenhouse gas, "Life Cycle Greenhouse Gas Emissions of Marcellus Shale Gas," appeared in Environmental Research Letters

Boyer, Elizabeth W.

131

Technical, economic, and environmental impact study of converting Uzbekistan transportation fleets to natural gas operation. Export trade information  

SciTech Connect

This study, conducted by Radian International, was funded by the U.S. Trade and Development Agency. The report assesses the feasibility (technical, economic and environmental) of converting the Uzbek transportation fleets to natural gas operation. The study focuses on the conversion of high fuel use vehicles and locomotives to liquefied natural gas (LNG) and the conversion of moderate fuel use veicles to compressed natural gas (CNG). The report is divided into the following sections: Executive Summary; (1.0) Introduction; (2.0) Country Background; (3.0) Characterization of Uzbek Transportation Fuels; (4.0) Uzbek Vehicle and Locomotive Fleet Characterization; (5.0) Uzbek Natural Gas Vehicle Conversion Shops; (6.0) Uzbek Natural Gas Infrastructure; (7.0) Liquefied Natural Gas (LNG) for Vehicular Fuel in Uzbekistan; (8.0) Economic Feasibility Study; (9.0) Environmental Impact Analysis; References; Appendices A - S.

NONE

1997-04-30

132

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

PubMed

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

Olaguer, Eduardo P

2012-08-01

133

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

134

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

PubMed

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 ?(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

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

2013-01-01

135

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

PubMed

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

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

2005-04-01

136

Gas  

MedlinePLUS

... swallow and the breakdown of undigested food by bacteria in the large intestine. Certain foods may cause gas. Foods that produce gas in one person may not cause gas in another. You can reduce the amount of gas you have by Drinking lots of water and non-fizzy drinks Eating more slowly so ...

137

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

PubMed

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

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

2015-01-01

138

Hyphenated gas chromatography-mass spectrometry analysis of 3-mercaptohexan-1-ol and 3-mercaptohexyl acetate in wine: Comparison with results of other sampling procedures via a robust regression.  

PubMed

This work describes a new purge and trap gas chromatography electron impact mass spectrometry (PT-GC-EIMS) method for quantifying 3-mercaptohexan-1-ol (3-MH) and 3-mercaptohexyl acetate (3-MHA), two molecules able to characterize some wines with their tropical scents. Firstly the experimental conditions of the purge and trap extraction (sample temperature, extraction time, trap temperature, flow rate) following a multivariate approach were optimized. Then the method through the construction of the calibration curves and the establishment of the detection limits was validated. The purge and trap procedure appears faster and more sensitive than both the headspace solid phase microextraction (HS-SPME) and the solid phase extraction (SPE) procedures, reaching detection limits for the two thiols closer to their sensory thresholds. Evidence of similar performances of the three sampling methods considered was gained comparing the results relevant to same wine samples. The Theil's regression method was used for purpose of comparison. PMID:18573368

Fedrizzi, Bruno; Versini, Giuseppe; Lavagnini, Irma; Badocco, Denis; Nicolini, Giorgio; Magno, Franco

2008-07-21

139

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

PubMed

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 10³ [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

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

2011-10-01

140

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

SciTech Connect

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.

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

2005-09-01

141

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

SciTech Connect

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.

Daniel, G.

2013-06-18

142

Geochemical investigations for deep gas drilling in Siljan Impact Structure, Sweden  

SciTech Connect

The geochemical analysis program for the Gravberg 1 well in the Siljan Ring (impact structure in Sweden) monitors and evaluates for scientific and commercial purposes the gas encountered in the borehole which has penetrated Precambrian crystalline rocks to a depth of 6.6 km. At the well, three different systems measure hydrocarbons C/sub 1/-C/sub 5/. Inorganic gases, H/sub 2/, CO/sub 2/, O/sub 2/, He, and Ra, are also measured. Offsite laboratories conduct more sophisticated studies of a routine and experimental nature. These include headspace and desorbed gas analysis, and isotopic analysis of hydrocarbons, helium, and hydrogen. Two types of hydrocarbon gases have been encountered. Hydrocarbon concentration is highest in the dolerite intrusions, about 4 to 10 times higher than in granite. In the dolerites, the hydrocarbons consist of up to 98% methane, whereas in the granite the methane content is 50-70% The dolerite gases contain small proportions of unsaturates; in the granite, the C/sub 2/-C/sub 4/ oplefins are in equal amounts with the saturates. The dolerites contain isotopically heavy methane (deltaC/sup 13/ generally -10 to -24 o/oo), similar to abiogenic gases. In the granite, the methane is lighter (delta C/sup 13/ generally -23 to 36 o/oo). Experiments show that almost all the hydrocarbons in the granite are associated with the magnetic fraction; this does not hold for the dolerites. The hydrocarbon in the granites may be formed from CO and H/sub 2/ by magnetite catalysis (Fischer-Tropsch reaction) but other explanations may be possible. Hydrogen is a prominent part of the gas mix; it exceeds methane concentration normally by an order of magnitude. The hydrogen could be indigenous. Helium is found mainly below 6 km; isotopic analyses show that the helium is of crystal origin.

Castano, J.R.; Jeffrey, A.W.A.; Kaplan, I.R.; Karlsson, D.

1988-01-01

143

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

NASA Technical Reports Server (NTRS)

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".

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

2010-01-01

144

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

PubMed Central

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

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

2013-01-01

145

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

PubMed

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

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

2013-01-01

146

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

PubMed

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 ?g/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

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

2014-10-01

147

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

PubMed

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

Zielinska, Barbara; Campbell, Dave; Samburova, Vera

2014-12-01

148

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...

149

IMPACTS OF GREENHOUSE GAS AND PARTICULATE EMISSIONS FROM WOODFUEL PRODUCTION AND END-USE IN SUB-SAHARAN AFRICA  

E-print Network

IMPACTS OF GREENHOUSE GAS AND PARTICULATE EMISSIONS FROM WOODFUEL PRODUCTION AND END-USE IN SUB the atmospheric radiation budget. We use empirical studies and published emission factors to estimate with charcoal has 2-10 times the global warming effect of cooking the same meal with firewood and 5-16 times

Kammen, Daniel M.

150

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

PubMed

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

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

2014-05-01

151

Green House Gas Emissions and the Economic Impacts EU Climate Change Policies (in Finnish with an English abstract\\/summary)  

Microsoft Academic Search

This paper describes the main features of a model developed for fore-casting greenhouse gas emissions in major EU countries and Finland as well as for simulating the economic impacts of EU climate change policies. Energy demand and emissions are determined in the model by economic growth and weather conditions. Output growth especially in the energy intensive industry determines the consumption

Olavi Rantala

2007-01-01

152

Impact of reduced tillage and cover cropping on the greenhouse gas budget of a maize/soybean rotation ecosystem  

E-print Network

of increased decomposition of the cover crop residue. N2O fluxes were similar in both treatments duringImpact of reduced tillage and cover cropping on the greenhouse gas budget of a maize suggested that conservation tillage (Lal and Bruce, 1999; Lal, 2003, 2004) and cover cropping during fallow

Minnesota, University of

153

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

NASA Astrophysics Data System (ADS)

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.

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

2003-12-01

154

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

SciTech Connect

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.

Amy Childers

2011-03-30

155

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

SciTech Connect

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.

Daniel, W. E.

2013-02-13

156

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

SciTech Connect

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.

Parnell, John (University of Aberdeen, Aberdeen, UK); Newsom, Horton E. (University of New Mexico, Albuquerque, NM); Blamey, Nigel J. F. (New Mexico Tech, Socorro, NM); Boslough, Mark Bruce Elrick

2010-10-01

157

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

PubMed

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

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

2009-12-01

158

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

SciTech Connect

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.

Tegen, S.

2005-08-01

159

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

SciTech Connect

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.

Tegen, S.

2006-05-01

160

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

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

161

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

PubMed

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

Olivetti, Elsa; Gül?en, Ece; Malça, João; Castanheira, Erica; Freire, Fausto; Dias, Luis; Kirchain, Randolph

2014-07-01

162

Impact of Ionized Gas Outflows in the Evolution of Seyfert Galaxies  

NASA Astrophysics Data System (ADS)

By means of adaptive optics assisted integral field spectroscopy, we investigate the impact of feedback from Active Galactic Nuclei (AGN) driven outflows in the evolution of Seyfert galaxies. These data enable us to study at very high angular resolution 0.08”) the 2D kinematics of Br? and the high ionization line [SiVI] in nearby AGN. The spatially resolved kinematics can be modeled as a combination of an outflow bicone and a rotating disk coincident with the molecular gas. In half of the AGN measured so far, the kinetic energy of the outflows appears sufficient to provide the eagerly-sought “AGN feedback” invoked to explain fundamental galaxy properties such as the M-sigma relation. While in these objects the radio jet is extended and clearly interacting with the interstellar medium (ISM), in the other half of AGN -in which the outflow power is at least one order of magnitude less than predicted in feedback models- the radio jet is weak and compact. This suggests a link between jet power and outflow power. In addition, the inferred ionized outflowing mass can be remarkably large, 2 or more orders of magnitude greater than that required to fuel the AGN at its current luminosity, but it’s comparable to the estimated inflow rates to the central 5-25 pc. These two facts point to an interaction between the outflow and the ISM (probably the outflow is mass-loaded by the ISM and disrupting the conditions necessary for star formation).

Mueller Sanchez, Francisco; Malkan, M. A.; Hicks, E. K.; Davies, R.; Evans, D. A.

2013-01-01

163

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

NASA Astrophysics Data System (ADS)

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.

Erickson, Peter; Lazarus, Michael

2014-09-01

164

Phytoremediation of polycyclic aromatic hydrocarbons in manufactured gas plant-impacted soil.  

PubMed

Contamination of soil by hazardous substances poses a significant threat to human, environmental, and ecological health. Cleanup of the contaminants using destructive, invasive technologies has proven to be expensive and more importantly, often damaging to the natural resource properties of the soil, sediment, or aquifer. Phytoremediation is defined as the cleanup of contaminated sites using plants. There has been evidence of enhanced polycyclic aromatic hydrocarbons (PAHs) degradation in rhizosphere soils for a limited number of plants. However, research focusing on the degradation of PAHs in the rhizosphere of trees is lacking. The objective of this study was to assess the potential use of trees to enhance degradation of PAHs located in manufactured gas plant-impacted soils. In greenhouse studies with intact soil cores, acenaphthene, anthracene, fluoranthene, naphthalene, and phenanthrene decreased significantly (p < 0.05) in green ash (Fraxinus pennsylvanica Marshall) and hybrid poplar (Populus deltoides x P. nigra DN 34) phytoremediation treatments when compared to the unplanted soil control. Increases in PAH microbial degraders in rhizosphere soil were observed when compared to unvegetated soil controls. In addition, the rate of degradation or biotransformation of PAHs was greatest for soils with black willow (Salix nigra Marshall), followed by poplar, ash, and the unvegetated controls. These results support the hypothesis that a variety of plants can enhance the degradation of target PAHs in soil. PMID:16151227

Spriggs, Thomas; Banks, M Katherine; Schwab, Paul

2005-01-01

165

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

NASA Astrophysics Data System (ADS)

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.

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

2011-08-01

166

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

NASA Astrophysics Data System (ADS)

Agricultural ecosystems are major sources of greenhouse gas (GHG) emissions, specifically nitrous oxide (N2O) and carbon dioxide (CO2). An important method of researching 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 the validated DNDC model was used for sensitivity tests on three variables under consideration: climatic factors, soil properties, and agricultural management. Results indicate that: (1) the factors that N2O emissions are most sensitive to nitrogen fertilizer application rate, manure amendment and residue return rate; (2) CO2 emission increases with increasing manure amendment, residue return rate and initial soil organic carbon (SOC); and (3) net global warming potential (GWP) increases with increasing N fertilizer application rate and decreases as 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.

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

2011-03-01

167

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

168

The Impact of Etna's Volcanic Gas Emissions on Soils and Vegetation  

NASA Astrophysics Data System (ADS)

Mt. Etna is considered to be at present, on long time average, the major volcanic gas emitter in the world, accounting for about 10 percent of world-wide average volcanic emissions of CO2 and SO2. Hydrogen Chloride and HF emissions are proportionally high with measured values of 750 and 190 tons day respectively. Such huge emissions, significantly overwhelming the regional anthropogenic mass output, have a strong impact at least on local scale. Its strong influence has been assessed for example on rainwater chemistry, which display increasing contents of F (up to 227 mg/l), Cl (up to 1410 mg/l) and SO4 (up to 481 mg/l) with decreasing distances from the summit craters. The corresponding high wet deposition values (up to 72 mg/m2 day for SO4, 226 mg/m2 day for Cl and 21 mg/m2 day for F) are comparable or even higher than those measured in heavily polluted areas of central Europe. Dry deposition, estimated with a network of passive samplers, represents an additional load on the local environment especially for sulfur. The geographical pattern of wet and dry deposition reflects the dilution of the volcanic plume with increasing distance and its prevailing displacement to the east by atmospheric circulation. To study the impact on Etnean soils, 52 soil-sampling sites were chosen all around Mt Etna in areas with minor anthropic disturbance, at distances from the summit craters between 3.7 and 16 km. At each sampling site, a composite sample of the first 5 cm of the soil profile of at least 4 points within an area of about 100 m2 was collected. Samples were analyzed for bulk chemical composition and for leachable anion and cation content. Although the results display a large variability, the strong impact of crater emissions can be seen especially in fluorine content and in pH of soil solutions, which closely resemble the deposition pattern. But despite the huge acidic deposition, Etnean soils do not show the adverse effects noted in the heavily polluted areas of Central Europe because of the high acid buffering capacity of these young volcanic soils. Furthermore about 60 samples of leaves and needles of 6 different plant species were collected for the study of the impact of Etna gaseous emissions on its vegetation cover. Preliminary results indicate fluorine and sulfur content, which are sometimes higher than in heavily polluted areas, and with generally higher contents in conifers with respect to broad-leaved species. But the effects on vegetation at Etna seem significantly low, likely because: i) the acidity of the emitted sulfur and halogen compounds is buffered by the presence of large quantities of volcanic silicate ash and/or carbonate dust; ii) local vegetation species has developed some kind of resistance to the "volcanic pollution".

D'Alessandro, W.; Aiuppa, A.; Bellomo, S.; Parello, F.

2003-12-01

169

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

PubMed

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 ?g 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 ?g 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

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

2015-02-01

170

Aerosols versus Greenhouse Gas Climate Effects: Impacts on Temperature and Precipitation Changes and Implications for Decision-making  

NASA Astrophysics Data System (ADS)

Over the 20th Century, it is understood that anthropogenic emissions of aerosols have partially offset the influence of the greenhouse gas emissions on the global-mean and continental surface temperatures, consistent with the difference in their respective radiative forcings. The effect of aerosols versus greenhouse gases on precipitation and hydrologic cycle, however, is not so straightforward. Using a set of NOAA/ GFDL global climate model simulations, the impacts due to anthropogenic aerosol emissions are characterized and compared with those due to greenhouse gas emissions. This is performed for the global and continental spatial scales. The degree of aerosol offset of the greenhouse gas effects in terms of evaporation at the surface and precipitation can be greater than that occurring in the case of surface temperature, with some regions experiencing an impact that is more governed by aerosols than by the greenhouse gas emissions. These results have significant implications for decision-making concerning future emissions and mitigation/ adaptation to climate change. The removal of aerosols from the atmosphere in the near future to obtain improvements in air quality would exacerbate the warming due to greenhouse gases arising over a large part of the globe. However, the corresponding impacts due to aerosol reductions on the global evaporation and precipitation in the 21st Century, including changes in regional phenomena such as the Asian precipitation, are less clear but are important to understand. Compounding the problem is the set of uncertainties arising from lack of or incomplete knowledge of the various species of aerosols (e.g., scattering and absorbing aerosols; sulfate, soot, dust), interactions of aerosols with clouds, and the nature of the emissions scenario. An accompanying challenge is to accurately characterize and communicate this exceptional issue in climate change science to the diverse group of stakeholders, sectors and decision-makers, who are actively seeking quantification of the linkage between emissions and surface temperature and precipitation impacts.

Ramaswamy, V.; Horowitz, L. W.; Ming, Y.; Schwarzkopf, M. D.; Levy, H.

2011-12-01

171

How we made a High-impact Gas Discovery in a Maturing Basin (Western Canada)  

Microsoft Academic Search

EnCana's 2001 gas discovery at Ferrier, Alberta in the lower Mississippian Banff Formation was a significant new pool discovery in a long-active, competitive part of a maturing basin. Subsequent development of the pool has produced > 50 Bcf equivalent gas + condensate, at gross production rates of up to 100 mmcfe\\/day. The gas has been produced from dolomitized crinoidal grainstone

Marian J. Warren

172

Environmental impact assessment: enhanced gas recovery by massive hydraulic fracturing in Lincoln County, West Virginia  

Microsoft Academic Search

The US DOE has contracted with the Columbia Gas Transmission Corp. to share the cost of a field experiment of the Massive Hydraulic Fracturing (MHF) process for natural gas recovery. The project is part of a larger program to develop reservoir stimulation techniques for natural gas within the Devonian Shale formation of the Appalachian region. The experiment will take place

Schnorr

1978-01-01

173

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

174

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

PubMed

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

Currie, D R; Isaacs, Leanne R

2005-04-01

175

Impact of flue gas desulfurization gypsum application on water quality in a coastal plain soil.  

PubMed

There are growing concerns regarding the fate of nutrients, especially phosphorus (P), from land application of animal waste. One approach being studied to reduce runoff losses of P is to treat manure or the soil receiving manure with chemical amendments such as gypsum. This study used rainfall simulations to examine the impact of flue gas desulfurization (FGD) gypsum application on runoff nutrient losses on a Coastal Plains soil (Luverne sandy loam; fine, mixed, semiactive, thermic Typic Hapludults). Four rates of FGD gypsum (0, 2.2, 4.4, and 8.9 Mg ha) were applied to plots of Coastal Bermudagrass ( L.) that had received application of 13.4 Mg ha poultry litter. Plots with 8.9 Mg ha FGD gypsum but no poultry litter and plots with neither poultry litter nor FGD gypsum were also used. Rainfall simulation was used to generate water runoff for 60 min, and samples were analyzed for soluble reactive P (SRP) and soluble Al, B, Ca, Cu, Fe, K, Mg, Mn, Na, and Zn. Total concentration of Ca, Mg, K, Na, Fe, Mn, and Zn and concentration of heavy metals Ar, Hg, Al, Sb, Ba, Be, Cd, Cr, Co, Cu, Pb, Ni, Si, V, Se, Tl, and hexavalent chromium were also analyzed. Results indicated a maximum of 61% reduction in SRP concentration in runoff with the application of 8.9 Mg ha FGD gypsum. This translated to a 51% reduction in total SRP load during the 60-min runoff event. Concentrations of heavy metals in runoff were all found to be below detection limits. The results indicated that use of 4.4 Mg ha FGD gypsum on Coastal Plains pastures receiving poultry litter could be an effective method of reducing SRP losses to the environment. PMID:25602560

Torbert, H Allen; Watts, Dexter B

2014-01-01

176

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

NASA Astrophysics Data System (ADS)

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.

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

2009-03-01

177

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

PubMed

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

Evans, Jeffrey S; Kiesecker, Joseph M

2014-01-01

178

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

SciTech Connect

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.

Jennings, D.M.

1980-01-01

179

Impact  

NASA Technical Reports Server (NTRS)

Impact, emergency escape and crash survival protection are studied. Accleration, the G system of units, data interpretation, and human tolerance limits are summarized, along with physiological and biochemical response to impact. Biomechanical factors of impact are also cited.

Snyder, R. G.

1973-01-01

180

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

NASA Technical Reports Server (NTRS)

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.

Ngo, Khiem Viet; Tumer, Irem Y.

2003-01-01

181

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

PubMed

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

Tarr, Joel A

2014-01-01

182

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

PubMed

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 ?g/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

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

2013-04-01

183

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

NASA Astrophysics Data System (ADS)

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).

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

2014-09-01

184

Summary report; Impact of FGD systems emdash availability losses experienced by flue gas desulfurization systems  

Microsoft Academic Search

In 1991, the Flue Gas Desulfurization Task Force, under the direction of the North American Electric Reliability Council's (NERC) Generating Availability Trend Evaluations (GATE) Working Group, released a report on the performance of flue gas desulfurization (FGD) systems. This paper is an abridgement of the report that required two years of research and analysis by that task force. The overriding

G. M. Curley; R. Danz

1992-01-01

185

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

Microsoft Academic Search

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

D. R. Blake; F. S. Rowland

1995-01-01

186

78 FR 62012 - Transcontinental Gas Pipeline Company; Notice of Availability of the Draft Environmental Impact...  

Federal Register 2010, 2011, 2012, 2013

...authorization to expand its natural gas pipeline system in New York to provide...facilities along its existing pipeline system in Pennsylvania and...Atmospheric Administration, National Marine Fisheries Service; and City...of new 26-inch-diameter pipeline to deliver natural gas...

2013-10-11

187

78 FR 26354 - Transcontinental Gas Pipeline Company, LLC; Notice of Intent to Prepare an Environmental Impact...  

Federal Register 2010, 2011, 2012, 2013

...gas facilities by Transcontinental Gas Pipeline Company, LLC (Transco), in the Commission's...Rockaway Project, a 3.2-mile-long pipeline in Queens and Kings Counties, New York...S. Army Corps of Engineers, National Marine Fisheries Service, and New York...

2013-05-06

188

Gas-gun reverse-ballistic technique for multiple-particle impacts  

NASA Astrophysics Data System (ADS)

A reverse-ballistic impact technique is described for multiple impacts of macroscopic particles on a disk of material. The disk is accelerated in a sabot. The spatial and temporal separation of the particles can be controlled by the relative positions of the particles in a frangible mechanical support. Example results for closely spaced simultaneous impacts of multiple steel spheres with steel disks show synergistic effects in the perforation response of the disks. A hollow sabot design permits the sabot to move past the disk and spheres after impact, to minimize the influence of the sabot on the perforation process. Experiments have been performed at speeds up to 970 m/s.

Holt, William H.; Mock, Willis

2004-05-01

189

75 FR 16450 - Kern River Gas Transmission Company; Notice of Availability of the Draft Environmental Impact...  

Federal Register 2010, 2011, 2012, 2013

...Environmental Impact Statement for the Proposed Apex Expansion Project March 26, 2010. The...environmental impact statement (EIS) for the Apex Expansion Project proposed by Kern River...of the construction and operation of the Apex Expansion Project in accordance with...

2010-04-01

190

75 FR 45109 - Kern River Gas Transmission Company; Notice of Availability of the Final Environmental Impact...  

Federal Register 2010, 2011, 2012, 2013

...Environmental Impact Statement for the Proposed APEX Expansion Project July 23, 2010. The...environmental impact statement (EIS) for the Apex Expansion Project proposed by Kern River...of the construction and operation of the Apex Expansion Project in accordance with...

2010-08-02

191

The impact of fluid advection on gas hydrate stability: Investigations at sites of methane seepage offshore Costa Rica  

NASA Astrophysics Data System (ADS)

Fluid flow through marine sediments drives a wide range of processes, from gas hydrate formation and dissociation, to seafloor methane seepage including the development of chemosynthetic ecosystems, and ocean acidification. Here, we present new seismic data that reveal the 3D nature of focused fluid flow beneath two mound structures on the seafloor offshore Costa Rica. These mounds have formed as a result of ongoing seepage of methane-rich fluids. We show the spatial impact of advective heat flow on gas hydrate stability due to the channelled ascent of warm fluids towards the seafloor. The base of gas hydrate stability (BGHS) imaged in the seismic data constrains peak heat flow values to ?60 mW m and ?70 mW m beneath two separate seep sites known as Mound 11 and Mound 12, respectively. The initiation of pronounced fluid flow towards these structures was likely controlled by fault networks that acted as efficient pathways for warm fluids ascending from depth. Through the gas hydrate stability zone, fluid flow has been focused through vertical conduits that we suggest developed as migrating fluids generated their own secondary permeability by fracturing strata as they forced their way upwards towards the seafloor. We show that Mound 11 and Mound 12 (about 1 km apart on the seafloor) are sustained by independent fluid flow systems through the hydrate system, and that fluid flow rates across the BGHS are probably similar beneath both mounds. 2D seismic data suggest that these two flow systems might merge at approximately 1 km depth, i.e. much deeper than the BGHS. This study provides a new level of detail and understanding of how channelled, anomalously-high fluid flow towards the seafloor influences gas hydrate stability. Thus, gas hydrate systems have good potential for quantifying the upward flow of subduction system fluids to seafloor seep sites, since the fluids have to interact with and leave their mark on the hydrate system before reaching the seafloor.

Crutchley, G. J.; Klaeschen, D.; Planert, L.; Bialas, J.; Berndt, C.; Papenberg, C.; Hensen, C.; Hornbach, M. J.; Krastel, S.; Brueckmann, W.

2014-09-01

192

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

NASA Astrophysics Data System (ADS)

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.

Ezelle, Ralph Wayne, Jr.

2011-12-01

193

The impact of gravity segregation on multiphase non-Darcy flow in hydraulically fractured gas wells  

E-print Network

) ............................................................................................................ 14 2.2 Barree et al. (2006) relative permeability data for a light weight ceramic proppant fit to a Corey type equation............................................................ 17 2.3 Reservoir gas-water relative permeabilities... (Tidwell and Parker, 1996). When segregated flow occurs, there are areas in the fracture with single-phase gas flow separate and above that of single-phase water flow. Using conventional laboratory proppant pack experimental results may cause inaccurate...

Dickins, Mark Ian

2008-10-10

194

Impact of Fuel Interchangeability on dynamic Instabilities in Gas Turbine Engines  

SciTech Connect

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.

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

2007-03-01

195

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 ...

196

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

SciTech Connect

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.

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

2011-07-01

197

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

PubMed Central

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

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

2013-01-01

198

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

PubMed

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

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

2014-05-01

199

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

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

200

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

SciTech Connect

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.

Blake, D.R.; Rowland, F.S. [Univ. of California, Irvine, CA (United States)

1995-08-18

201

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

NASA Technical Reports Server (NTRS)

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.

Povinelli, Louis A.

2001-01-01

202

Greenhouse gas impacts of ethanol from Iowa corn: Life cycle assessment versus system wide approach  

Microsoft Academic Search

Life cycle assessment (LCA) is the standard approach used to evaluate the greenhouse gas (GHG) benefits of biofuels. However, the need for the appropriate use of LCA in policy contexts is highlighted by recent findings that corn-based ethanol may actually increase GHG emissions. This is in contrary to most existing LCA results. LCA estimates can vary across studies due to

Hongli Feng; Ofir D. Rubin; Bruce A. Babcock

2010-01-01

203

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

SciTech Connect

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.

Reichenauer, Thomas G., E-mail: thomas.reichenauer@ait.ac.at [Health and Environment Department, Environmental Resources and Technologies, AIT - Austrian Institute of Technology GmbH, 2444 Seibersdorf (Austria); Watzinger, Andrea; Riesing, Johann [Health and Environment Department, Environmental Resources and Technologies, AIT - Austrian Institute of Technology GmbH, 2444 Seibersdorf (Austria); Gerzabek, Martin H. [Institute of Soil Research, Department of Forest and Soil Sciences, University of Natural Resources and Applied Life Sciences, Peter Jordan-Strasse 82, 1190 Vienna (Austria)

2011-05-15

204

Impact of Liquefied Natural Gas usage and payload size on Hybrid Wing Body aircraft fuel efficiency  

E-print Network

This work assessed Hybrid Wing Body (HWB) aircraft in the context of Liquefied Natural Gas (LNG) fuel usage and payload/range scalability at three scales: H1 (B737), H2 (B787) and H3 (B777). The aircraft were optimized for ...

Mody, Pritesh (Pritesh Chetan)

2010-01-01

205

Characterization of the global impact of low temperature gas plasma on vegetative microorganisms  

Microsoft Academic Search

Plasma medicine and also decontamination of bacteria with physical plasmas is a promising new field of life science with huge interest especially for medical applications. Despite numerous successful applications of low temperature gas plasmas in medicine and decontamination, the fundamental nature of the interactions between plasma and microorganisms is to a large extent unknown. A detailed knowledge of these interactions

T. Winter; J. Winter; M. Polak; K. Kusch; U. Mader; R. Sietmann; J. Ehlbeck; K. D. Weltmann; M. Hecker; H. Kusch

2011-01-01

206

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...

207

Impact of mass balance calculations on adsorption capacities in microporous shale gas reservoirs  

Microsoft Academic Search

Determination of the adsorbed reservoir capacity of gas shales by adsorption analyses as done routinely by mass balance maybe in significant error if the effects of pore-size dependent void volume (porosity) is not considered. It is shown here that with increasing pressure, helium, which is invariably used to measure void volume, can access pores that are not available for adsorption

Daniel J. K. Ross; R. Marc Bustin

2007-01-01

208

Integrating Gas Turbines with Cracking Heaters - Impact on Emissions and Energy Efficiency  

E-print Network

Zink Company, Tulsa, Oklahoma - 1993 (7) ? Investigation on the in-flame NO reburning in turbine exhaust gas - Mario Ditaranto, J?rgen Hals, Tor Bj?rge, Proceedings of the Combustion Institute 32 (2009) 2659?2666 (8) ? Modeling of nitrogen...

Platvoet, E.

2011-01-01

209

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...

210

Impact of Gas Adsorption Induced Coal Matrix Damage on the Evolution of Coal Permeability  

NASA Astrophysics Data System (ADS)

It has been widely reported that coal permeability can change from reduction to enhancement due to gas adsorption even under the constant effective stress condition, which is apparently inconsistent with the classic theoretical solutions. This study addresses this inconsistency through explicit simulations of the dynamic interactions between coal matrix swelling/shrinking induced damage and fracture aperture alteration, and translations of these interactions to permeability evolution under the constant effective stress condition. We develop a coupled coal-gas interaction model that incorporates the material heterogeneity and damage evolution of coal, which allows us to couple the progressive development of damage zone with gas adsorption processes within the coal matrix. For the case of constant effective stress, coal permeability changes from reduction to enhancement while the damage zone within the coal matrix develops from the fracture wall to further inside the matrix. As the peak Langmuir strain is approached, the decrease of permeability halts and permeability increases with pressure. The transition of permeability reduction to permeability enhancement during gas adsorption, which may be closely related to the damage zone development in coal matrix, is controlled by coal heterogeneity, external boundary condition, and adsorption-induced swelling.

Zhu, W. C.; Wei, C. H.; Liu, J.; Xu, T.; Elsworth, D.

2013-11-01

211

Using biodiversity methods to assess the impacts of oil and gas development in tropical rain forests  

Microsoft Academic Search

Oil and gas development in tropical rain forests has attracted international attention because of the potentially adverse effects on the forest ecosystems. Biodiversity is a topic of particular concern, but is difficult to assess for small areas of disturbance. In July 1992 we used light traps to compare insect diversity at canopy and ground level as a means of detecting

D. P. Reagan; X. Silva del Poso

1995-01-01

212

A new impact test for the identification of a dynamic crack propagation criterion using a gas-gun device  

NASA Astrophysics Data System (ADS)

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.

Nistor, I.; Pantalé, O.; Caperaa, S.

2006-08-01

213

Structural determination of nerve agent markers using gas chromatography mass spectrometry after derivatization with 3-pyridyldiazomethane.  

PubMed

Nerve agents are a class of organophosphorous chemicals that are prohibited under the Chemical Weapons Convention. Their degradation products, phosphonic acids, are analyzed as markers of nerve agent contamination and use. Because the phosphonic acids are non-volatile and very polar, their identification by GC-MS requires a derivatization step prior to analysis. Standard derivatization methods for gas-chromatography electron-impact mass-spectrometry analysis give very similar spectra for many alkyl phosphonic acid isomers, which complicates the identification process. We present a new reagent, 3-pyridyldiazomethane, for preparing picolinyl ester derivatives of alkyl methylphosphonic acids facilitating the determination of their structure by enhancing predictable fragmentation of the O-alkyl chain. This fragmentation is directed by the nitrogen nucleus of the pyridyl moiety that abstracts hydrogen from the O-alkyl chain, inducing radical cleavage of the carbon-carbon bonds and thereby causing extensive fragmentation that can be used for detailed structure elucidation of the O-alkyl moiety. The separability of related isomers was tested by comparing the spectra of the picolinyl esters formed from twelve hexyl methylphosphonic acid isomers. Spectral library matches and principal component analysis showed that the picolinyl esters were more effectively separated than the corresponding trimethylsilyl derivatives used in the standard operating procedures. The suggested method will improve the unambiguous structural determination process for phosphonic acids. PMID:23832937

Nyholm, Jenny Rattfelt; Gustafsson, Tomas; Östin, Anders

2013-07-01

214

Impacts of oil and gas development on the recreation and tourism off the Florida straits  

SciTech Connect

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.

Bell, F.

1991-05-01

215

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 ...

216

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...

217

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

SciTech Connect

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 (H{sub 2}S, NH{sub 3}, HCN, AsH{sub 3}, PH{sub 3}, HCl, NaCl, KCl, AS{sub 3}, NH{sub 4}NO{sub 3}, NH{sub 4}OH, KNO{sub 3}, HBr, HF, and HNO{sub 3}) on the performance and lifetime of commercially available and generic (prepared in-house) WGS and FT catalysts; ferrochrome-based high-temperature WGS catalyst (HT-WGS, Shiftmax 120�, Süd-Chemie), low-temperature Cu/ZnO-based WGS catalyst (LT-WGS, Shiftmax 230�, Süd-Chemie), and iron- and cobalt-based Fischer-Trospch synthesis catalysts (Fe-FT & Co-FT, UK-CAER). In this project, TDA Research, Inc. collaborated with a team at the University of Kentucky Center for Applied Energy Research (UK-CAER) led by Dr. Burt Davis. We first conducted a detailed thermodynamic analysis. The three primary mechanisms whereby the contaminants may deactivate the catalyst are condensation, deposition, and reaction. AsH{sub 3}, PH{sub 3}, H{sub 2}S, HCl, NH{sub 3} and HCN were found to have a major impact on the Fe-FT catalyst by producing reaction products, while NaCl, KCl and PH{sub 3} produce trace amounts of deposition products. The impact of the contaminants on the activity, selectivity, and deactivation rates (lifetime) of the catalysts was determined in bench-scale tests. Most of the contaminants appeared to adsorb onto (or react with) the HT- and LT-WGS catalysts were they were co-fed with the syngas: � 4.5 ppmv AsH{sub 3} or 1 ppmv PH{sub 3} in the syngas impacted the selectivity and CO conversion of both catalysts; � H{sub 2}S slowly degraded both WGS catalysts; - A binary mixture of H{sub 2}S (60 ppmv) and NH{sub 3} (38 ppmv) impacted the activity of the LT-WGS catalyst, but not the HT-WGS catalyst � Moderate levels of NH{sub 3} (100 ppmv) or HCN (10 ppmv) had no impact � NaCl or KCl had essentially no effect on the HT-WGS catalyst, but the activity of the LT-WGS catalyst decreased very slowly Long-term experiments on the Co-FT catalyst at 260 and 270 °C showed that all of the contaminants impacted it to some extent with the exception of NaCl and HF. Irrespective of its source (e.g., NH{sub 3}, KNO{sub 3}, or HNO{sub 3}), ammonia suppressed the activity of the Co-FT catalyst to a moderate degree. There was essentially no impact the Fe-FT catalyst when up to 100 ppmw halide compounds (NaCl and KCl), or up to 40 ppmw alkali bicarbonates (NaHCO{sub 3} and KHCO{sub 3}). After testing, BET analysis showed that the surface areas, and pore volumes and diameters of both WGS catalysts decreased during both single and binary H2S and NH3 tests, which was attributed to sintering and pore filling by the impurities. The HT-WGS catalyst was evaluated with XRD after testing in syngas that contained 1 ppmv PH{sub 3}, or 2 ppmv H{sub 2}S, or both H{sub 2}S (60 ppmv) and NH{sub 3} (38 ppmv). The peaks became sharper during testing, which was indicative of crystal growth and sintering, but no new phases were detected. After LT-WGS tests (3-33 ppmv NH{sub 3} and/or 0-88 ppmv H{sub 2}S) there were a few new phases that appeared, including sulfides. The fresh Fe-FT catalyst was nanocrystalline and amorphous. ICP-AA spectroscopy and other methods (e.g., chromatography) were used to analyze for

Gokhan Alptekin

2012-09-30

218

Popular Epidemiology and "Fracking": Citizens' Concerns Regarding the Economic, Environmental, Health and Social Impacts of Unconventional Natural Gas Drilling Operations.  

PubMed

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

Powers, Martha; Saberi, Poune; Pepino, Richard; Strupp, Emily; Bugos, Eva; Cannuscio, Carolyn C

2014-11-13

219

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

SciTech Connect

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).

Kirschner, C.E. (Geological Survey, Union, WA (United States)); Grantz, A.; Mullen, M.W. (Geological Survey, Menlo Park, CA (United States))

1992-05-01

220

Evolving shale gas management: water resource risks, impacts, and lessons learned.  

PubMed

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

Rahm, Brian G; Riha, Susan J

2014-05-01

221

Impact of Intrafractional Bowel Gas Movement on Carbon Ion Beam Dose Distribution in Pancreatic Radiotherapy  

SciTech Connect

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.

Kumagai, Motoki [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); School of Health Sciences, Niigata University, Niigata (Japan); Hara, Ryusuke [Hospital, National Institute of Radiological Sciences, Chiba (Japan); Mori, Shinichiro [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan)], E-mail: shinshin@nirs.go.jp; Yanagi, Takeshi [Hospital, National Institute of Radiological Sciences, Chiba (Japan); Asakura, Hiroshi [Accelerator Engineering Corporation, Chiba (Japan); Kishimoto, Riwa; Kato, Hirotoshi; Yamada, Shigeru; Kandatsu, Susumu; Kamada, Tadashi [Hospital, National Institute of Radiological Sciences, Chiba (Japan)

2009-03-15

222

Land use change and the impact on greenhouse gas exchange in north Australian savanna soils  

Microsoft Academic Search

Savanna ecosystems are subject to accelerating land use change as human demand for food and forest products increases. Land use change has been shown to both increase and decrease greenhouse gas fluxes from savannas and considerable uncertainty exists about the non-CO2 fluxes from the soil. We measured methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) over a complete wet-dry

S. P. P. Grover; S. J. Livesley; L. B. Hutley; H. Jamali; B. Fest; J. Beringer; K. Butterbach-Bahl; S. K. Arndt

2011-01-01

223

Impacts of shale gas wastewater disposal on water quality in western Pennsylvania.  

PubMed

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

Warner, Nathaniel R; Christie, Cidney A; Jackson, Robert B; Vengosh, Avner

2013-10-15

224

Dietary sodium bicarbonate, cool temperatures, and feed withdrawal: impact on arterial and venous blood-gas values in broilers.  

PubMed

Sodium bicarbonate (NaHCO3) has been used successfully in mammals and birds to alleviate pulmonary hypertension. Experiment 1 was designed to provide measurements of arterial and venous blood-gas values from unanesthetized male broilers subjected to a cool temperature (16 degrees C) challenge and fed either a control diet or the same diet alkalinized by dilution with 1% NaHCO3. The incidences of pulmonary hypertension syndrome (PHS, ascites) for broilers fed the control or bicarbonate diets were 15.5 and 10.5%, respectively (P = 0.36, NS). Non-ascitic broilers fed the control diet were heavier than those fed the bicarbonate diet on d 49 (2,671 vs. 2,484 g, respectively); however, other comparisons failed to reveal diet-related differences in heart weight, pulse oximetry values, electrocardiogram amplitudes, or blood-gas values (P > 0.05). When the data were resorted into categories based on right:total ventricular weight ratios (RV:TV) indicative of normal (RV:TV < 0.28) or elevated (RV:TV > or = 0.28) pulmonary arterial pressures, broilers with elevated RV:TV ratios had poorly oxygenated arterial blood that was more acidic, had high partial pressure of CO2 (PCO2), and had higher HCO3 concentrations when compared with broilers with normal RV:TV ratios. Experiment 2 was conducted to determine if metabolic variations associated with differences in feed intake or environmental temperature potentially could mask an impact of diet composition on blood-gas values. Male broilers maintained at thermoneutral temperature (24 degrees C) either received feed ad libitum or had the feed withdrawn > or = 12 h prior to blood sampling. Broilers fed ad libitum had lower venous saturation of hemoglobin with O2, higher venous PCO2, and higher arterial HCO3 concentrations than broilers subjected to feed withdrawal. Broilers in experiment 2 fed ad libitum and exposed to cool temperatures (16 degrees C) had lower arterial partial pressure of O2 and higher venous PCO2 than broilers fed ad libitum and maintained at 24 degrees C. Overall, these results demonstrate that changes in diet composition (control vs. 1% NaHCO3 diets) had minimal impact on arterial and venous blood-gas variables when compared with the more dramatic differences associated with feed intake (ad libitum vs. > or = 12 h withdrawal), environmental temperature (24 vs. 16 degrees C), and the pathogenesis associated with PHS (RV:TV < 0.28 vs. > or = 0.28). PMID:12710474

Wideman, R F; Hooge, D M; Cummings, K R

2003-04-01

225

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

Microsoft Academic Search

BackgroundMany 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 FindingsWe propose a systematic way to forecast patterns of future energy development and calculate impacts to species

Holly E. Copeland; Kevin E. Doherty; David E. Naugle; Amy Pocewicz; Joseph M. Kiesecker; Adina Maya Merenlender

2009-01-01

226

Impact of Power Generation Mix on Life Cycle Assessment and Carbon Footprint Greenhouse Gas Results  

Microsoft Academic Search

SummaryThe mix of electricity consumed in any stage in the life cycle of a product, process, or industrial sector has a significant effect on the associated inventory of emissions and environmental impacts because of large differences in the power generation method used. Fossil?fuel?fired or nuclear?centralized steam generators; large?scale and small?scale hydroelectric power; and renewable options, such as geothermal, wind, and

Joe Marriott; H. Scott Matthews; Chris T. Hendrickson

2010-01-01

227

SIMPLE TECHNIQUES FOR ASSESSING IMPACTS OF OIL AND GAS OPERATIONS ON PUBLIC LANDS- USE OF A PHOTOIONIZATION DETECTOR TO EVALUATE HYDROCARBONS IN THE SUBSURFACE  

Microsoft Academic Search

Simple, cost-effective techniques are needed for land managers to assess the environmental impacts of oil and gas production activities on public lands, so that sites may be prioritized for remediation or for further, more formal assessment. Field-portable instruments provide real-time data and allow the field investigator to extend an assessment beyond simply locating and mapping obvious impacts. Field investigators can

James K. Otton; Robert A. Zielinski

228

Impacts of Application of Methane Fermentation Digested Liquid on Green House Gas Emissions and Nitrogen Leaching from Upland Field  

NASA Astrophysics Data System (ADS)

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.

Nakamura, Masato; Fujikawa, Tomonori; Yuyama, Yoshito; Maeda, Morihiro; Yamaoka, Masaru

229

Cooking a `Sausage': the impact of merger shocks in cluster gas and galaxy evolution  

NASA Astrophysics Data System (ADS)

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 H? 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 H? 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.

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

230

Land use change and the impact on greenhouse gas exchange in north Australian savanna soils  

NASA Astrophysics Data System (ADS)

Savanna ecosystems are subject to accelerating land use change as human demand for food and forest products increases. Land use change has been shown to both increase and decrease greenhouse gas fluxes from savannas and considerable uncertainty exists about the non-CO2 fluxes from the soil. We measured methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) over a complete wet-dry seasonal cycle at three replicated sites of each of three land uses: savanna, young pasture and old pasture (converted from savanna 5-7 and 25-30 yr ago, respectively) in the Douglas Daly region of northern Australia. The effect of break of season rains at the end of the dry season was investigated with two irrigation experiments. Land use change from savanna to pasture increased net greenhouse gas fluxes from the soil. Pasture sites were a weaker sink for CH4 than savanna sites and, under wet conditions, old pastures turned from being sinks to a significant source of CH4. Nitrous oxide emissions were generally very low, in the range of 0 to 5 ?g N2O-N m-2 h-1, and under dry conditions soil uptake of N2O was apparent. Break of season rains produced a small, short lived pulse of N2O up to 20 ?g N2O-N m-2 h-1, most evident in pasture soil. Annual cumulative soil CO2 fluxes increased after clearing, with savanna (14.6 t CO2-C ha-1 yr-1) having the lowest fluxes compared to old pasture (18.5 t CO2-C ha-1 yr-1) and young pasture (20.0 t CO2-C ha-1 yr-1). Clearing savanna increased soil-based greenhouse gas emissions from 53 to ~70 t CO2-equivalents, a 30% increase dominated by an increase in soil CO2 emissions and shift from soil CH4 sink to source. Seasonal variation was clearly driven by soil water content, supporting the emerging view that soil water content is a more important driver of soil gas fluxes than soil temperature in tropical ecosystems where temperature varies little among seasons.

Grover, S. P. P.; Livesley, S. J.; Hutley, L. B.; Jamali, H.; Fest, B.; Beringer, J.; Butterbach-Bahl, K.; Arndt, S. K.

2011-09-01

231

Land use change and the impact on greenhouse gas exchange in north Australian savanna soils  

NASA Astrophysics Data System (ADS)

Savanna ecosystems are subjected to accelerating land use change as human demand for food and forest products increases. Land use change has been shown to both increase and decrease greenhouse gas fluxes from savannas and considerable uncertainty exists about the non-CO2 fluxes from the soil. We measured methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) over a complete wet-dry seasonal cycle at three replicate sites of each of three land uses: savanna, young pasture and old pasture (converted from savanna 5-7 and 25-30 yr ago, respectively) in the Douglas Daly region of Northern Australia. The effect of break of season rains at the end of the dry season was investigated with two irrigation experiments. Land use change from savanna to pasture increased net greenhouse gas fluxes from the soil. Pasture sites were a weaker sink for CH4 than savanna sites and, under wet conditions, old pastures turned from being sinks to a significant source of CH4. Nitrous oxide emissions were generally very low, in the range of 0 to 5 ?g N2O-N m-2 h-1, and under dry conditions soil uptake of N2O was apparent. Break of season rains produced a small, short lived pulse of N2O up to 20 ?g N2O-N m-2 h-1, most evident in pasture soil. Annual cumulative soil CO2 fluxes increased after clearing, with savanna (14.6 t CO2-C ha-1 yr-1) having the lowest fluxes compared to old pasture (18.5 t CO2-C ha-1 yr-1) and young pasture (20.0 t CO2-C ha-1 yr-1). Clearing savanna increased soil-based greenhouse gas emissions from 53 to ∼ 70 t CO2-equivalents, a 30% increase dominated by an increase in soil CO2 emissions and shift from soil CH4 sink to source. Seasonal variation was clearly driven by soil water content, supporting the emerging view that soil water content is a more important driver of soil gas fluxes than soil temperature in tropical ecosystems where temperature varies little among seasons.

Grover, S. P. P.; Livesley, S. J.; Hutley, L. B.; Jamali, H.; Fest, B.; Beringer, J.; Butterbach-Bahl, K.; Arndt, S. K.

2012-01-01

232

Amperometric Enzyme-based Gas Sensor for Formaldehyde: Impact of Possible Interferences  

PubMed Central

In this work, cross-sensitivities and environmental influences on the sensitivity and the functionality of an enzyme-based amperometric sensor system for the direct detection of formaldehyde from the gas phase are studied. The sensor shows a linear response curve for formaldehyde in the tested range (0 - 15 vppm) with a sensitivity of 1.9 ?A/ppm and a detection limit of about 130 ppb. Cross-sensitivities by environmental gases like CO2, CO, NO, H2, and vapors of organic solvents like methanol and ethanol are evaluated as well as temperature and humidity influences on the sensor system. The sensor showed neither significant signal to CO, H2, methanol or ethanol nor to variations in the humidity of the test gas. As expected, temperature variations had the biggest influence on the sensor sensitivity with variations in the sensor signal of up to 10 % of the signal for 5 vppm CH2O in the range of 25 - 30 °C.

Achmann, Sabine; Hämmerle, Martin; Moos, Ralf

2008-01-01

233

Cellulosic ethanol from municipal solid waste: a case study of the economic, energy, and greenhouse gas impacts in California.  

PubMed

As cellulosic ethanol technologies advance, states could use the organic content of municipal solid waste as a transportation fuel feedstock and simultaneously reduce externalities associated with waste disposal. We examine the major processes required to support a lignocellulosic (employing enzymatic hydrolysis) municipal solid waste-to-ethanol infrastructure computing cost, energy, and greenhouse gas effects for California. The infrastructure is compared against the Business As Usual case where the state continues to import most of its ethanol needs from the Midwest. Assuming between 60% and 90% practical yields for ethanol production, California could produce between 1.0 and 1.5 billion gallons per year of ethanol from 55% of the 40 million metric tonnes of waste currently sent to landfills annually. The classification of organic wastes and ethanol plant operation represent almost the entire system cost (between $3.5 and $4.5 billion annually) while distribution has negligible cost effects and savings from avoided landfilling is small. Fossil energy consumption from Business As Usual decreases between 82 and 130 PJ largely due to foregone gasoline consumption. The net greenhouse gas impacts are ultimately dependent on how well landfills control their emissions of decomposing organics. Based on the current landfill mix in the state, the cellulosic infrastructure would experience a slight gain in greenhouse gas emissions. However, net emissions can rise if organics diversion releases carbon that would otherwise be flared and sequestered. Emissions would be avoided if landfills are not capable of effectively controlling emissions during periods of active waste decay. There is currently considerable uncertainty surrounding the recovery efficiency of landfill emissions controls. In either case, burying lignin appears to be better than burning lignin because of its decay properties, energy and carbon content We estimate the breakeven price for lignocellulosic ethanol between $2.90 and $3.47/gal (mu = $3.13/gal). PMID:19708339

Chester, Mikhail; Martin, Elliot

2009-07-15

234

Life cycle greenhouse gas impacts of ethanol, biomethane and limonene production from citrus waste  

NASA Astrophysics Data System (ADS)

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).

Pourbafrani, Mohammad; McKechnie, Jon; MacLean, Heather L.; Saville, Bradley A.

2013-03-01

235

European greenhouse gas fluxes from land use: the impact of expanding the use of dedicated bioenergy crops.  

NASA Astrophysics Data System (ADS)

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.

Hastings, Astley; Böttcher, Hannes; Clifton-Brown, John; Fuchs, Richard; Hillier, Jon; Jones, Ed; Obersteiner, Michael; Pogson, Mark; Richards, Mark; Smith, Pete

2013-04-01

236

The impact of oxygen on the morphology of gas-phase prepared Au nanoparticles  

SciTech Connect

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.

Pohl, D.; Surrey, A.; Schultz, L. [IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden (Germany); TU Dresden, Institute of Condensed Matter Physics, D-01062 Dresden (Germany); Rellinghaus, B. [IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden (Germany)

2012-12-24

237

Volcanic gas emissions from Mount Erebus and their impact on the Antarctic environment  

SciTech Connect

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

Zreda-Gostynska, G.; Kyle, P.R. [Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico (United States)] [Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico (United States); Finnegan, D. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Prestbo, K.M. [Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico (United States)] [Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico (United States)

1997-07-01

238

Free and forced convection in high permeability soils: impact on gas flux at the soil-atmosphere interface  

NASA Astrophysics Data System (ADS)

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 4.2×0.6 [g/m^2h]. Under TCV, with a temperature gradient of 8.8 [°C/m], CO2 flux was 11.15×0.05 [g/m^2h]. Under no-wind isothermal conditions the measured flux was 2.45×0.6 [g/m^2h]. The CO2 flux was the highest when both WIC and TCV conditions were imposed simultaneously (14.6×1.1 [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.

Levintal, E.; Dragila, M. I.; Weisbrod, N.

2013-12-01

239

Gas Gun Impact Testing of PZT 95/5, Part 1: Unpoled State  

SciTech Connect

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.

FURNISH,MICHAEL D.; SETCHELL,ROBERT E.; CHHABILDAS,LALIT C.; MONTGOMERY,STEPHEN T.

2000-01-01

240

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

Microsoft Academic Search

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

Marte Ulvestad; Indra Overland

2012-01-01

241

Greenhouse gas exchange in grasslands: impacts of climate, intensity of management and other factors  

NASA Astrophysics Data System (ADS)

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.

Smith, K. A.

2003-04-01

242

Impact of seasonal temperature and pressure changes on methane gas production, dissolution, and transport in unfractured sediments  

Microsoft Academic Search

Bottom water temperature seasonality is reflected in the sediment free gas depthFree methane gas may dissolve and fuel anaerobic methane oxidationThe free gas depth can be used as a proxi for anaerobic methane oxidation rates

J. M. Mogollón; A. W. Dale; I. L'Heureux; P. Regnier

2011-01-01

243

Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissions  

NASA Astrophysics Data System (ADS)

North Australian tropical savanna accounts for 12% of the world’s 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 Australia’s 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.

Hutley, L. B.; Evans, B. J.; Beringer, J.; Cook, G. D.; Maier, S. M.; Razon, E.

2013-12-01

244

Impact of reduced tillage on the greenhouse gas balance - a meta-analysis  

NASA Astrophysics Data System (ADS)

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.

Don, Axel; Jantz, Marc

2013-04-01

245

Wastewater treatment process impact on energy savings and greenhouse gas emissions.  

PubMed

The objective of this research was to assess the energy consumption of wastewater treatment plants (WWTPs), to apply a mathematical model to evaluate their carbon footprint, and to propose energy saving strategies that can be implemented to reduce both energy consumption and greenhouse gas (GHG) emissions in Greece. The survey was focused on 10 WWTPs in Greece with a treatment capacity ranging from 10,000 to 4,000,000 population equivalents (PE). Based on the results, annual specific energy consumption ranged from 15 to 86 kWh/PE. The highest energy consumer in all the WWTPs was aeration, accounting for 40-75% of total energy requirements. The annual GHG emissions varied significantly according to the treatment schemes employed and ranged between 61 and 161 kgCO2e/PE. The highest values of CO2 emissions were obtained in extended aeration systems and the lowest in conventional activated sludge systems. Key strategies that the wastewater industry could adopt to mitigate GHG emissions are identified and discussed. A case study is presented to demonstrate potential strategies for energy savings and GHG emission reduction. Given the results, it is postulated that the reduction of dissolved oxygen (DO) set points and sludge retention time can provide significant energy savings and decrease GHG emissions. PMID:25633956

Mamais, D; Noutsopoulos, C; Dimopoulou, A; Stasinakis, A; Lekkas, T D

2015-01-01

246

Characterization of lithology and reservoir rock for deep gas drilling in Siljan Impact Structure, Sweden  

SciTech Connect

The Gravberg 1 well in the Siljan impact structure in Sweden has been drilled entirely in granite and dolerite intrusions of Precambrian age to a present depth of 6.6 km. Study of the cuttings at the well site included a lithologic description, with emphasis on quantifying mineralogical, textural, and pore-space parameters that affect porosity and permeability and that can indicate the potential presence of a fractured reservoir. Important mineral parameters are epidote, reddish feldspar, chlorite, and other alteration products. Textural parameters include the presence of fractures, cataclastic and brecciated graikns, vugs, and drusy crystals. Although rare, the presence of drusy crystals clearly shows that open fractures are present. The study is also geared to identify minerals that affect wireline logs (e.g., alteration products such as chlorite,sericite, and illite, and heavy minerals such as pyritic and magnetite4). Cuttings examination is crucial as relatively few cores or sidewalls have been recovered. Laboratory studies incorporating capillary pressure tests, SEM, and thin-section petrography (in polarized and fluorescent light) reveal that the samples contain a bimodal pore structure composed of larger pores representing the microfractures and smaller pores representing the intercrystalline microporosity developed within altered grains. Porosity in the granites averages 0.96% (typical Swedish granite is 0.5%), and the permeability is 0.003-0.027 md.

Castano, J.R.; Sneider, R.M.; Bolger, G.W.

1988-01-01

247

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)

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 Drösler (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. Drösler, M. 2005. Trace Gas Exchange and climatic relevance of bog ecosystems, Southern Germany, phD-thesis, TU München, München 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

Pohl, M.; Hagemann, U.; Liebe, M.; Sommer, M.; Augustin, J.

2012-04-01

248

Health And Economic Impact Of Greenhouse Gas Emissions Reduction In Indonesia: SO2  

NASA Astrophysics Data System (ADS)

The objective of this study is to assess Indonesia's air quality. This comprised an assessment of Indonesia's air pollution levels and their impact on the development of health and the economics. Estimates are given of concentrations of one of the major pollutants: sulfur dioxide (SO2). Emissions are estimated for Indonesian region, based on energy consumption, derived from the MERGE simulation model. The air pollution levels projection for the year 2000 to the year 2100 are based on the IPCC scenarios, extended with some mitigation scenarios for the energy sector. If the Organisation for Economic Co-operation and Development (OECD) countries reduce their emissions, Indonesian oil consumption increases, and the emissions of SO2 are higher than in the baseline scenario. Health problems increase substantially, peaking to the middle of century in the A1B and B1 scenarios, and rising to the end of century in the A2 and B2 scenarios, while the health problem costs will be the highest during the middle of century in the A1B and B1 scenarios and toward the end of century in the A2 and B2 scenarios. With international trade in emission permits, Indonesia would be higher than in the baseline scenario, since more and more oil and coal using in domestic sources of energy, followed by higher of health problem cases and higher of health problem costs. The total cases of health problem are higher 18.5% than in the baseline scenario. If all countries reduce their emission, including Indonesia, the total concentrations of SO2 are lower than previous scenarios. The cases of health problem associated with SO2 are lower than in the baseline scenario and follow by the lower of the health problem costs. The costs of health problem associated with SO2 are to 35% lower than in the baseline scenario during the simulation period.

Susandi, A.

2004-12-01

249

Unravelling the impact of hydrocarbon structure on the fumarate addition mechanism - a gas-phase ab initio study.  

PubMed

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

Bharadwaj, Vivek S; Vyas, Shubham; Villano, Stephanie M; Maupin, C Mark; Dean, Anthony M

2015-01-28

250

The Impact of Region, Nitrogen Use Efficiency, and Grower Incentives on Greenhouse Gas Mitigation in Canola (Brassica napus) Production  

NASA Astrophysics Data System (ADS)

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.

Hammac, W. A.; Pan, W.; Koenig, R. T.; McCracken, V.

2012-12-01

251

Evaluating impacts of CO2 gas intrusion into a confined sandstone aquifer: Experimental results  

SciTech Connect

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.

Qafoku, Nikolla; Lawter, Amanda R.; Shao, Hongbo; Wang, Guohui; Brown, Christopher F.

2014-12-31

252

Long-range transport and its impact on trace gas variability at selected GAW stations  

NASA Astrophysics Data System (ADS)

To improve our understanding of the impact and the time-scales of atmospheric pollution transport and to understand the mixing ratios of non- or weakly reactive gases observed within monitoring programmes such as the Global Atmosphere Watch (GAW) programme global scale atmospheric transport models provide valuable and requisite information. Atmospheric transport described in a Lagrangian framework, contrary to the Eulerian approach, does not suffer from numerical diffusion. In addition, information on transport times of newly released emissions is easily accessible in the Lagragian concept. Therefore, Lagrangian models are the ideal tool to answer the questions raised above. To this end the Lagrangian particle dispersion model FLEXPART (Version 8.0) was extended and set up on the global domain with 3 million particles that are permanently transported based on ECMWF wind fields. All particles carry 9 different counters that indicate times since certain atmospheric regions were left: 1 counter for each of the 6 WMO regions keeping track of atmospheric boundary layer contact, 2 counters for inter-hemispheric transport, and 1 counter for stratosphere-troposphere exchange. Thirteen different species are represented with each particle: 1 atmospheric air tracer, 6 carbon monoxide (CO) and 6 methane (CH4) tracers according to emissions from the 6 WMO regions. Gridded emissions are taken up by particles passing through the atmospheric boundary layer of each grid cell and are based on constant EDGAR3.2FT2000 (anthropogenic) and 8-daily GFED (v2) (biomass-burning) emission inventories. Degradation of CO and CH4 (and also CO production from CH4 degradation) is considered by temperature and pressure dependent reaction with hydroxyl radicals (OH). Monthly OH fields are taken from HTAP. Global monthly mean fields for each species, each clock and 11 age-classes are produced by the model and offer detailed insight into the time-scales of transport and the contributions from different source regions. Furthermore, receptor concentrations (daily temporal resolution) are produced for selected GAW sites and allow for model inter-comparison and interpretation of observations. In this contribution we present details on the model concept and first results obtained for an iterative spin-up run for the year 2001.

Henne, S.; Brunner, D.; Klausen, J.; Buchmann, B.

2009-04-01

253

The impact of using biodiesel/marine gas oil blends on exhaust emissions from a stationary diesel engine.  

PubMed

The purpose of this work was to investigate the impact of marine gas oil (MGO)/biodiesel blends on the exhaust emissions and fuel consumption in a single cylinder, stationary, diesel engine. Three different origins of biodiesel were used as the blending feedstock with the reference MGO, at proportions of 5 and 10% by volume. Methyl esters were examined according to the automotive FAME standard EN 14214. The baseline MGO and biodiesel blends were examined according to ISO 8217:2005 specifications for the DMA category. Independently of the biodiesel used, a decrease of PM, HC, CO and CO(2) emissions was observed. Emissions of NO(x) were also lower with respect to MGO. This reduction in NO(x) may be attributed to some physicochemical properties of the fuels applied, such as the higher cetane number and the lower volatility of methyl esters. Reductions in PM for biodiesel blends were lower in the exhaust than those of the reference fuel which was attributed to the oxygen content and the near absence of sulphur and aromatics compounds in biodiesel. However, a slight increase in fuel consumption was observed for the biodiesel blends that may be tolerated due to the exhaust emissions benefits. Brake thermal efficiency was also determined. Unregulated emissions were characterized by determining the soluble organic fraction content of the particulate matter. PMID:18988104

Karavalakis, G; Tzirakis, E; Mattheou, L; Stournas, S; Zannikos, F; Karonis, D

2008-12-01

254

Uncertainty analysis of life cycle greenhouse gas emissions from petroleum-based fuels and impacts on low carbon fuel policies.  

PubMed

The climate change impacts of U.S. petroleum-based fuels consumption have contributed to the development of legislation supporting the introduction of low carbon alternatives, such as biofuels. However, the potential greenhouse gas (GHG) emissions reductions estimated for these policies using life cycle assessment methods are predominantly based on deterministic approaches that do not account for any uncertainty in outcomes. This may lead to unreliable and expensive decision making. In this study, the uncertainty in life cycle GHG emissions associated with petroleum-based fuels consumed in the U.S. is determined using a process-based framework and statistical modeling methods. Probability distributions fitted to available data were used to represent uncertain parameters in the life cycle model. Where data were not readily available, a partial least-squares (PLS) regression model based on existing data was developed. This was used in conjunction with probability mixture models to select appropriate distributions for specific life cycle stages. Finally, a Monte Carlo simulation was performed to generate sample output distributions. As an example of results from using these methods, the uncertainty range in life cycle GHG emissions from gasoline was shown to be 13%-higher than the typical 10% minimum emissions reductions targets specified by low carbon fuel policies. PMID:21043516

Venkatesh, Aranya; Jaramillo, Paulina; Griffin, W Michael; Matthews, H Scott

2011-01-01

255

Impact of the renewable oxygenate standard for reformulated gasoline on ethanol demand, energy use, and greenhouse gas emissions  

SciTech Connect

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.

Stork, K.C.; Singh, M.K.

1995-04-01

256

Sulfur and Iron Speciation in Gas-rich Impact-melt Glasses from Basaltic Shergottites Determined by Microxanes  

NASA Technical Reports Server (NTRS)

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.

Sutton, S. R.; Rao, M. N.; Nyquist, L. E.

2008-01-01

257

Gas-phase reactive nitrogen near Grand Teton National Park: Impacts of transport, anthropogenic emissions, and biomass burning  

NASA Astrophysics Data System (ADS)

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.

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

258

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

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.

Ye Zhuang; Stanley J. Miller [University of North Dakota, Grand Forks, ND (United States). Energy & Environmental Research Center

2006-05-15

259

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, 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.

Fritz, K.; Harris, S.; Edenborn, H.M.; Sams, J.

2011-01-01

260

78 FR 41949 - Notice of Intent To Prepare an Environmental Impact Statement for the Lower Gas Hills...  

Federal Register 2010, 2011, 2012, 2013

...for the Lower Gas Hills Conventional Uranium Project, Fremont County, WY AGENCY...proposed Lower Gas Hills Conventional Uranium Project (Project) in Fremont County, Wyoming. The Project is a proposed uranium exploration and development...

2013-07-12

261

Toward the Impact of Fuel Evaporation-Combustion Interaction on Spray Combustion in Gas Turbine Combustion Chambers. Part I: Effect of Partial Fuel Vaporization on Spray Combustion  

Microsoft Academic Search

\\u000a This work aims at investigating the impact of the interaction between evaporation process and combustion on spray combustion\\u000a characteristics in gas turbine combustion chambers. It is subdivided into two parts. The first part studies how the evaporation\\u000a process affects the behavior of partially pre-vaporized spray combustion. The second part attempts to answer the question\\u000a how the fuel evaporation process behaves

Amsini Sadiki; W. Ahmadi; Mouldi Chrigui; J. Janicka

262

Reversible and irreversible impacts of greenhouse gas emissions in multi-century projections with the NCAR global coupled carbon cycle-climate model  

Microsoft Academic Search

The legacy of historical and the long-term impacts of 21st century greenhouse gas emissions on climate, ocean acidification,\\u000a and carbon-climate feedbacks are investigated with a coupled carbon cycle-climate model. Emission commitment scenarios with\\u000a zero emissions after year 2100 and 21st century emissions of 1,800, 900, and 0 gigatons of carbon are run up to year 2500.\\u000a The reversibility and irreversibility

Thomas L. Frölicher; Fortunat Joos

2010-01-01

263

Studies of soluble organics in simulated in situ oil-shale retort water by electron impact and chemical ionization from a combined gas chromatograph-mass spectrometer system  

Microsoft Academic Search

Retort water samples collected from the Laramie 10-ton simulated in-situ retort were examined by both electron impact (EI) and chemical ionization (CI) mass spectrometry with a Finnigan Model 3300 gas chromatograph--mass spectrometer (GC-MS). These water samples, formed in retorting Green River oil shale of either Utah or Colorado origin, were filtered, lyophilized, extracted with benzene, and esterified. Both the benzene

C. S. Wen; T. F. Yen; J. B. Knight; R. E. Poulson

1976-01-01

264

The Impacts of Permafrost Thaw on Land-Atmosphere Greenhouse Gas Exchange in Recent Decades over the Northern High Latitudes  

NASA Astrophysics Data System (ADS)

Coupled climate-carbon models project that the northern high latitudes will serve as a substantial land carbon sink during the 21st century because both climate warming and elevated global [CO2] favor increased productivity and carbon uptake in the region. However, these models lack many of the key processes governing high-latitude ecosystem processes, and none have accounted for soil organic matter (SOM) decomposition associated with permafrost thaw. In contrast, results based on incorporating all of the major factors controlling the high-latitude C budget in process model simulations suggest that the land-based sink of arctic and boreal ecosystems is currently weakening in part due to temperature-driven increases in SOM decomposition. We hypothesize that climate-driven warming will lead to increasing active layer thickness (ALT) and the thawing of previously frozen SOM, thus accelerating C and N cycling throughout the system. Competing mechanisms analyzed here include the positive feedback to warming through the decomposition and release of previously frozen SOM as CO2 and CH4, and the negative feedback associated with the uptake of atmospheric CO2 through net primary production (NPP) stimulated by increased vegetation N uptake. To parse out these mechanisms, we compared results from experimental simulations using the Terrestrial Ecosystem Model (TEM), which include explicit simulations of climate-driven ALT dynamics, with a 'control' simulation where ALT was held constant through the transient period. Across the Pan-Arctic domain over the 1990 to 2006 time period, model results show a wide-spread increase in the depth to permafrost, with a stronger trend over the discontinuous permafrost zone (3.9 mm/yr) than that over the continuous zone (2.5 mm/yr). Simulated ALT shows good agreement with observational data from the Circumpolar Active Layer Monitoring (CALM) network in terms of annual means, the range of spatial variability, and temporal patterns. Analysis of the simulation experiments provides an estimate of 280 TgC/yr thawed from previously frozen SOM. Despite the greater rate of thaw over the discontinuous permafrost zone, the majority (60%) of the thawed SOM (170 TgC/yr) was found in the continuous zone, reflecting the larger area and higher density of SOM of this zone. Of this thawed SOM, the TEM estimates that 615 MtCO2eq/yr was released to the atmosphere, with 71% (436 MtCO2eq/yr) from the continuous zone and 8.6% (52.9 MtCO2eq/yr) of the total forcing as CH4. While the impact of ALT dynamics on SOM decomposition resulted in a consistently strong increase in CO2 and CH4 emissions, the magnitude and even sign of the impact on NPP was more variable across sub-region and year. Compared to the control, TEM estimates an increase of 80 MtCO2eq/yr in NPP, which represents a 13% negative feedback relative to CO2 and CH4 emissions. With all components combined, our simulation experiment estimates a net greenhouse gas forcing of 535 MtCO2eq/yr directly tied to ALT dynamics modeled over the Pan-Arctic domain between 1990 and 2006. This represents a significant factor in the overall land-based greenhouse gas source of 640 MtCO2eq/yr, and an additional 6.8% contribution on top of the combined 7792 MtCO2eq/yr fossil fuel emissions from the eight Arctic nations over this time period.

Hayes, D. J.; Kicklighter, D. W.; McGuire, A. D.; Chen, M.; Zhuang, Q.; Melillo, J. M.; Wullschleger, S. D.

2012-12-01

265

Precious metal catalysts in the clean-up of biomass gasification gas Part 1: Monometallic catalysts and their impact on gasification gas composition  

Microsoft Academic Search

The performance of Rh, Ru, Pt, and Pd on modified commercial zirconia support (m-ZrO2) was compared to a benchmark Ni\\/m-ZrO2 catalyst in the presence of H2S in the clean-up of gasification gas from tar, methane, and ammonia. The aim was to produce ultra clean gas applicable for liquid biofuel production. In general, the activity towards the decomposition decreased in the

H. Rönkkönen; P. Simell; M. Reinikainen; M. Niemelä; O. Krause

2011-01-01

266

Global Impacts of Gas-Phase Chemistry-Aerosol Interactions on Direct Radiative Forcing by Anthropogenic Aerosols and Ozone  

NASA Technical Reports Server (NTRS)

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.

Liao, Hong; Seinfeld, John H.

2005-01-01

267

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)

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 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. 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.

Ervens, B.; Wang, Y.; Eagar, J.; Leaitch, W. R.; Macdonald, A. M.; Valsaraj, K. T.; Herckes, P.

2012-12-01

268

Incorporating DSM impacts in econometric models: Results from a recent model enhancement study by the New York State Electric & Gas Corporation  

SciTech Connect

Many utilities in the U.S. today continue to offer full-scale DSM programs aimed at reducing energy consumption and peak demand usage. Indeed, recent impact evaluation studies purport to show significant cumulative energy reductions that have been quantified in billing analysis studies of energy savings. Load forecasters now confront a clear need to account for these impacts in company sales forecasts. This is a particularly challenging task for utilities that still rely on econometric models to forecast sales. To-date, there is still no clear consensus with regard to how the impacts of DSM programs should be accounted for in econometric models and forecasts. This paper presents the results from a recent study conducted by the Applied Energy Group for New York State Electric & Gas focusing on an evaluation an assessment of alternative techniques for integrating DSM impacts from the company`s programs within the existing set of short-range econometric models used to forecast customer class sales. Specifically, this study will examine the following forecast adjustment methods currently used by utilities across the U.S. to account for DSM impacts; (1) Ex-post adjustments to the sales forecasts w/no modifications to the models. (2) The use of dummy and spline variables in econometric models to account for DSM impacts over time. (3) Adding-in DSM impact estimates to the sales history and re-estimating the models. (4) Incorporating index variables reflecting changes in appliance/equipment stock average efficiencies resulting from company DSM programs. This paper will review the strengths and weaknesses of each of these approaches with particular attention placed on the construction of energy efficiency index variables to capture the impacts of DSM. The index variable method will be illustrated using sales data, econometric models and simulation analysis results developed in the NYSEG study.

Golemboski, W.J. [Applied Energy Group, Inc., Binghamton, NY (United States); Ferris, F.S. [New York State Electric & Gas Corp., Binghamton, NY (United States)

1995-05-01

269

Potential impacts of two SO2 oxidation pathways on regional sulfate concentrations: Aqueous-phase oxidation by NO2 and gas-phase oxidation by Stabilized Criegee Intermediates  

NASA Astrophysics Data System (ADS)

We examine the potential impacts of two additional sulfate production pathways using the Community Multiscale Air Quality modeling system. First we evaluate the impact of the aqueous-phase oxidation of S(IV) by nitrogen dioxide using two published rate constants, differing by 1-2 orders of magnitude. The reaction with alternate high and low rate constants enhances monthly mean wintertime sulfate by 4-20% and 0.4-1.2% respectively. The reaction does not significantly impact summertime sulfate. The higher sulfate predictions in winter compare better with the observed data as the model tends to underpredict sulfate concentrations both in winter and summer. We also investigate the potential impact of the gas-phase oxidation of sulfur dioxide by the Stabilized Criegee Intermediate (SCI) using a recently measured rate constant for its reaction with sulfur dioxide. Model results indicate that the gas-phase oxidation of sulfur dioxide by the SCI does not significantly affect sulfate concentrations due to the competing reaction of the SCI with water vapor. The current estimate of the rate constant for the SCI reaction with water vapor is too high for the SCI reaction with sulfur dioxide to significantly affect sulfate production. However, a sensitivity analysis using a lower rate constant for the water vapor reaction suggests that the SCI reaction with sulfur dioxide could potentially enhance sulfate production in the model. Further study is needed to accurately measure the rate constants of the aqueous-phase oxidation of S(IV) by nitrogen dioxide and the gas-phase reaction of the SCI with water vapor.

Sarwar, Golam; Fahey, Kathleen; Kwok, Roger; Gilliam, Robert C.; Roselle, Shawn J.; Mathur, Rohit; Xue, Jian; Yu, Jianzhen; Carter, William P. L.

2013-04-01

270

Evaluation of impact of shale gas operations in the Barnett Shale region on volatile organic compounds in air and potential human health risks.  

PubMed

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

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

271

Mach one impact test apparatus utilizing an 18.4-mm-bore gas gun with a novel decelerating device.  

PubMed

The design and operation of a helium-gas-driven gun capable of operation to Mach one is described in this report. The gun utilizes a unique tapered-tube decelerator that captures the sabot and prevents gas discharge from the muzzle. This feature makes it possible to operate the gun in a normal laboratory environment without excessive safety precautions. PMID:18699612

Coppa, A P; Selden, G F; Mehan, R L

1979-07-01

272

Allocation of petroleum feedstock: Baltimore Gas and Electric Company, Sollers Point SNG Plant, Sollers Point, Baltimore County, Maryland. Final environmental impact statement  

SciTech Connect

An allocation of naphtha feedstock up to 2,186,000 barrels per year to Baltimore Gas and Electric Company (BG and E) to operate its synthetic natural gas (SNG) facility is being considered. The allocation would enable BG and E to produce 10,800,000 mcf of SNG during a 180 day period. Operation of the plant at design capacity is expected to result in annual pollution emissions as follows: 626.4 tons of sulfur oxides, 168.5 tons of nitrogen oxides and 21.6 tons of particulate matter. Incremental emissions due to plant operations relative to existing emissions in Baltimore County are less than 1%. All Federal and State air quality standards should be met. Treated effluent is to be discharged into the Patapasco River where the environmental impacts are not expected to be significant. The SNG facility has been designed to be in compliance with all applicable Federal, State and local effluent standards. Water consumption requirements of 335,000 gallons per day are not expected to significantly tax the area's water resources. Sound generated by the SNG facility will be inaudible or imperceptible. All other operational impacts on land use, population, visual quality, roadways, community facilities and services and ecological systems were judged to be minimal. Environmental impacts resulting from various alternatives ranging from full allocation through denial of an allocation are discussed.

Not Available

1978-04-01

273

Determination of 14 benzodiazepines and hydroxy metabolites, zaleplon and zolpidem as tert-butyldimethylsilyl derivatives compared with other common silylating reagents in whole blood by gas chromatography-mass spectrometry.  

PubMed

The most common commercially available silylating reagents, N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA), N,O-bis-(trimethylsilyl)trifluoroacetamide+1% trimethylchlorosilane (BSTFA+1% TMCS) and N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) were evaluated to achieve optimal derivatization conditions for analyzing various benzodiazepines based on gas chromatography-electron impact ionization-mass spectrometry (GC-EI-MS). Sensitivity, repeatability, retention times and stability of the derivatives, as well as specificity of mass fragmentation, were studied in detail. Also other parameters affecting the derivatization chemistry of benzodiazepines are discussed. tert-Butyldimethylsilyl (TBDMS) derivatives proved to be more stable, reproducible and sensitive than corresponding trimethylsilyl (TMS) derivatives for the GC-EI-MS analysis of benzodiazepines. Based on the TBDMS derivatives, a rapid, reliable, sensitive and quantitative GC-MS method was developed for the determination of 14 benzodiazepines and two hydroxy metabolites, as well as two non-benzodiazepine hypnotic agents, zolpidem and zaleplon, using 50 microl of whole blood. The method was completely validated in terms of accuracy, intra- and interday precision, limit of detection (LOD), limit of quantitation (LOQ), linearity, selectivity and extraction efficiency; these were all within the required limits, except for the accuracy of nitrazepam at a medium concentration level. PMID:15734157

Gunnar, Teemu; Ariniemi, Kari; Lillsunde, Pirjo

2005-04-25

274

The Techno-economic Impacts of Using Wind Power and Plug-In Hybrid Electric Vehicles for Greenhouse Gas  

E-print Network

The Techno-economic Impacts of Using Wind Power and Plug-In Hybrid Electric Vehicles for Greenhouse of the author. #12;ii Supervisory Committee The Techno-economic Impacts of Using Wind Power and Plug-In Hybrid reliance on fossil fuels. Plug-In Hybrid Electric Vehicles (PHEVs) and wind power represent two practical

Victoria, University of

275

Short-and long-term greenhouse gas and radiative forcing impacts of changing water management in Asian  

E-print Network

assessing green- house gas emissions from various sectors of the human economy and from a range, the initial change in radiative forcing was dominated by reduced CH4 emissions (i.e. a cooling for the first

276

Evaluation of the impact on emissions and fuel economy of converting two vehicles to compressed natural gas fuel. Technical report  

Microsoft Academic Search

The EPA was requested by the Department of Energy to perform testing on two late model vehicles which had been converted with on-the-market systems to run on compressed natural gas (CNG). The EPA was requested to measure vehicle emissions, fuel economy, and acceleration characteristics of the vehicles in stock configuration, modified running on gasoline, and modified-running on natural gas. The

Penninga

1981-01-01

277

Impact of seasonal temperature and pressure changes on methane gas production, dissolution, and transport in unfractured sediments  

NASA Astrophysics Data System (ADS)

A one-dimensional reaction-transport model is used to investigate the dynamics of methane gas in coastal sediments in response to intra-annual variations in temperature and pressure. The model is applied to data from two shallow water sites in Eckernförde Bay (Germany) characterized by low and high rates of upward fluid advection. At both sites, organic matter is buried below the sulfate-reducing zone to the methanogenic zone at sufficiently high rates to allow supersaturation of the pore water with dissolved methane and to form a free methane gas phase. The methane solubility concentration varies by similar magnitudes at both study sites in response to bottom water temperature changes and leads to pronounced peaks in the gas volume fraction in autumn when the methanic zone temperature is at a maximum. Yearly hydrostatic pressure variations have comparatively negligible effects on methane solubility. Field data suggest that no free gas escapes to the water column at any time of the year. Although the existence of gas migration cannot be substantiated by direct observation, a speculative mechanism for slow moving gas is proposed here. The model results reveal that free gas migrating upward into the undersaturated pore water will completely dissolve and subsequently be consumed above the free gas depth (FGD) by anaerobic oxidation of methane (AOM). This microbially mediated process maintains methane undersaturation above the FGD. Although the complexities introduced by seasonal changes in temperature lead to different seasonal trends for the depth-integrated AOM rates and the FGD, both sites adhere to previously developed prognostic indicators for methane fluxes based on the FGD.

Mogollón, J. M.; Dale, A. W.; L'Heureux, I.; Regnier, P.

2011-09-01

278

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)

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.

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

2014-10-01

279

[Health and environmental licensing: a methodological proposal for assessment of the impact of the oil and gas industry].  

PubMed

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

Barbosa, Eduardo Macedo; Barata, Matha Macedo de Lima; Hacon, Sandra de Souza

2012-02-01

280

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)

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.

Ervens, B.; Wang, Y.; Eagar, J.; Leaitch, W. R.; Macdonald, A. M.; Valsaraj, K. T.; Herckes, P.

2013-05-01

281

Using a two-layered sphere model to investigate the impact of gas vacuoles on the inherent optical properties of Microcystis aeruginosa  

NASA Astrophysics Data System (ADS)

A two-layered sphere model is used to investigate the impact of gas vacuoles on the inherent optical properties (IOPs) of the cyanophyte Microcystis aeruginosa. Enclosing a vacuole-like particle within a chromatoplasm shell layer significantly altered spectral scattering and increased backscattering. The two-layered sphere model reproduced features in the spectral attenuation and volume scattering function (VSF) that have previously been attributed to gas vacuoles. This suggests the model is good at least as a first approximation for investigating how gas vacuoles alter the IOPs. Measured Rrs was used to provide a range of values for the central value of the real refractive index, 1 + ?, for the shell layer using measured IOPs and a radiative transfer model. Sufficient optical closure was obtained for 1 + ? between 1.1 and 1.14, which had corresponding Chl a-specific phytoplankton backscattering, bb?*, between 3.9 and 7.2 × 10-3 m2 mg-1 at 510 nm. The bb?* values are in close agreement with the literature and in situ particulate backscattering measurements. Rrs simulated for a population of vacuolate cells was greatly enlarged relative to a homogeneous population. A sensitivity analysis of empirical algorithms for estimating Chl a in eutrophic/hypertrophic waters suggests these are robust under variable constituent concentrations and likely to be species-sensitive. The study confirms that gas vacuoles cause significant increase in backscattering and are responsible for the high Rrs values observed in buoyant cyanobacterial blooms. Gas vacuoles are therefore one of the most important bio-optical substructures influencing the IOPs in phytoplankton.

Matthews, M. W.; Bernard, S.

2013-12-01

282

Using a two-layered sphere model to investigate the impact of gas vacuoles on the inherent optical properties of M. aeruginosa  

NASA Astrophysics Data System (ADS)

A two-layered sphere model is used to investigate the impact of gas vacuoles on the inherent optical properties (IOPs) of the cyanophyte Microcystis aeruginosa. Enclosing a vacuole-like particle within a chromatoplasm shell layer significantly altered spectral scattering and increased backscattering. The two-layered sphere model reproduced features in the spectral attenuation and volume scattering function (VSF) that have previously been attributed to gas vacuoles. This suggests the model is good at least as a first approximation for investigating how gas vacuoles alter the IOPs. The central value of the real refractive index, 1+ ?, for the shell layer was determined using a radiative transfer model and measured remote sensing reflectance, Rrs, and IOP data. For a cell with 50% vacuole volume, the mean 1+ ? value for the shell layer was 1.12. The corresponding chl a specific phytoplankton backscattering coefficient, bb?*, ranged between 3.9 × 10-3 and 7.2 × 10-3 m2 mg-1 at 510 nm. This agrees closely with in situ particulate backscattering measurements and values reported elsewhere. Rrs simulated for a population of vacuolate cells was greatly enlarged relative to a homogeneous population. Empirical algorithms based on Rrs were derived for estimating chl a in eutrophic/hypertrophic waters dominated by M. aeruginosa. The study confirms that gas vacuoles cause significant increase in backscattering and are responsible for the high Rrs values observed in buoyant cyanobacterial blooms. Gas vacuoles are therefore one of the most important bio-optical substructures influencing the IOPs in phytoplankton.

Matthews, M. W.; Bernard, S.

2013-06-01

283

Impacts of individual fish movement patterns on estimates of mortality due to dissolved gas supersaturation in the Columbia River Basin.  

SciTech Connect

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.

Scheibe, Timothy D.; Richmond, Marshall C.; Fidler, Larry E.

2002-12-31

284

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)

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.

Calvello, M.; Esposito, F.; Trippetta, S.

2014-04-01

285

The impact of plasma-wall interaction on the gas mixing efficiency in electron cyclotron resonance ion sourcea)  

NASA Astrophysics Data System (ADS)

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.

Schachter, L.; Stiebing, K. E.; Dobrescu, S.

2012-02-01

286

The impact of plasma-wall interaction on the gas mixing efficiency in electron cyclotron resonance ion source  

SciTech Connect

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.

Schachter, L.; Dobrescu, S. [National Institute for Physics and Nuclear Engineering, Bucharest (Romania); Stiebing, K. E. [Institut fuer Kernphysik der J. W. Goethe-Universitaet, Frankfurt/Main (Germany)

2012-02-15

287

The Venezuelan gas industry. Venezuela and other South American countries: Impact on imports into the U.S.  

SciTech Connect

The role of Venezuela as a supplier of natural gas and derivative products to international markets will experience significant growth in the medium to long term, in the context of expected market opportunities and the development plans envisaged regarding crude oil production. Venezuela has a very large natural gas resource base, which presently amounts to 287 trillion cubic feet (TCF) in terms of proven, probable and possible reserves. Local consumption is highly concentrated in the oil, petrochemicals, aluminum, steel and electricity generation sectors. At the current consumption level of 1.1 TCF/year, proven reserves would supply the country`s requirements for over 120 years. Probable and possible reserves would more than double this figure. Certainly, this is an indication that one is dealing with a gas surplus country with significant potential for growth towards the exports markets. In this regard, Venezuela`s competitive position is further strengthened by the fact that a large portion of its reserves are associated to crude oil, which allows for low production and handling costs, and a relatively high liquid content. It is expected that the natural gas industry will grow rapidly over the coming years. A significant number of gas projects will be developed, including the expansion of existing ones and the construction of new facilities for recovery of natural gas liquids, the expansion of city methane networks replacing LPG as a domestic and industrial fuel, the construction of ethane recovery units for petrochemical uses, etc., all of which represent an additional liquids production of more than 100 {times} 10{sup 3} bbl/d that could be exported to the US and The Caribbean.

Mantellini, R. [PDVSA, Caracas (Venezuela)

1995-11-01

288

Enhanced Photoacoustic Gas Analyser Response Time and Impact on Accuracy at Fast Ventilation Rates during Multiple Breath Washout  

PubMed Central

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 10–90% 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

Horsley, Alex; Macleod, Kenneth; Gupta, Ruchi; Goddard, Nick; Bell, Nicholas

2014-01-01

289

Impacts of Increased Access to Oil & Natural Gas Resources in the Lower 48 Federal Outer Continental Shelf (released in AEO2007)  

EIA Publications

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.

2007-01-01

290

Impact of using high-density polyethylene geomembrane layer as landfill intermediate cover on landfill gas extraction.  

PubMed

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

Chen, Zezhi; Gong, Huijuan; Zhang, Mengqun; Wu, Weili; Liu, Yu; Feng, Jin

2011-05-01

291

MOF-74 building unit has a direct impact on toxic gas adsorption T. Grant Glover a,n  

E-print Network

, and a physically adsorbed compound, octane. Although a large number of toxic industrial chemicals exist-bed breakthrough testing in both dry and humid conditions. Octane breakthrough tests were performed to determine). The number of studies that have examined dynamic gas separations using MOFs is limited (Britt, et al., 2008

Yaghi, Omar M.

292

Gas-gun reverse-ballistic impact deformation and fracture of Armco iron Taylor specimens of differing grain sizes  

NASA Astrophysics Data System (ADS)

Taylor cylinder specimens of Armco iron have been prepared with average grain sizes of 20 and 91 microns. For each grain size, impacts were performed at 193 and 295 ms-1. The extent of fracturing that occurred at the specimen peripheries was only minor at the lower velocity but was pronounced at the greater velocity. Radial striations of softened or melted material were observed on the specimen and anvil disk impact surfaces. EPIC-2 predictions using the Zerilli-Armstrong constitutive equation are compared to the measured specimen outlines and to the extent of deformation twinning observed in metallographic examination of specimen longitudinal sections.

Holt, W. H.; Mock, W.; Clark, J. B.; Zerilli, F. J.; Armstrong, R. W.

1994-07-01

293

Impact of gas/particle partitioning of semivolatile organic compounds on source apportionment with positive matrix factorization.  

PubMed

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

Xie, Mingjie; Hannigan, Michael P; Barsanti, Kelley C

2014-08-19

294

New York State Electric and Gas Corporation`s Milliken Station clean coal technology demonstration project and its impacts on the local ambient air quality  

SciTech Connect

New York State Electric and Gas Corporation (NYSEG) has recently completed a program which upgraded the boiler combustion system and installed a high-efficiency flue gas desulfurization (FGD) system to demonstrate innovative emissions control technology and comply with the Clean Air Act Amendments of 1990. The demonstration project was conducted at NYSEG`s Milliken Station, in the Town of Lansing, New York. The primary objective of this clean coal technology demonstration (CCTD) project was to demonstrate a retrofit of energy-efficient SO{sub 2} and NO{sub x} control systems with minimal impact on overall plant efficiency. A four-year ambient monitoring program was conducted to evaluate the effects of the FGD system and combustion modifications on the local ambient air quality, the results of which are summarized in this paper. As part of NYSEG`s Milliken Station Clean Coal Technology Demonstration project, a flue gas desulfurization system was added as well as modifications to the combustion system and electrostatic precipitators. The demonstration project added a forced oxidation, formic acid-enhanced wet limestone FGD system, which was expected to reduce SO{sub 2} emissions by at least 90 percent. The project scope also consisted of combustion modifications and selective non-catalytic reduction (SNCR) technology to reduce NOx emissions. The burners were replaced with Low NOx Concentric Firing System Level 3 (LNCFS-3) burners to reduce NOx emissions while maintaining high combustion efficiency and acceptable fly ash loss on ignition (LOI). The electrostatic precipitators (ESP) on the two 160 MWe boilers were also upgraded to accommodate the wet flue gas desulfurization system. Upgrades of the ESP on each unit consisted of replacement of the internals and retirement of part of the original ESP.

Gendron, L.J. [ENSR Corp., Acton, MA (United States); Rahimi, M.; Savichky, W. [New York State Electric and Gas Corp., Binghamton, NY (United States)

1998-12-31

295

Impact of fly ash content and fly ash transportation distance on embodied greenhouse gas emissions and water consumption in concrete  

Microsoft Academic Search

Background, aim and scope  Fly ash, a by-product of coal-fired power stations, is substituted for Portland cement to improve the properties of concrete\\u000a and reduce the embodied greenhouse gas (GHG) emissions. Much of the world’s fly ash is currently disposed of as a waste product.\\u000a While replacing some Portland cement with fly ash can reduce production costs and the embodied emissions

Kate R. O’Brien; Julien Ménaché; Liza M. O’Moore

2009-01-01

296

Potential for a solids fire during an ITP waste tank deflagration and the impact on gas pressure  

SciTech Connect

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.

Thomas, J.K.

1993-07-01

297

LARGE-SCALE SHOCK-IONIZED AND PHOTOIONIZED GAS IN M83: THE IMPACT OF STAR FORMATION  

SciTech Connect

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.

Hong, Sungryong; Calzetti, Daniela [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Dopita, Michael A. [Research School of Astronomy and Astrophysics, Australian National University, ACT 2611 (Australia); Blair, William P. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Whitmore, Bradley C.; Bond, Howard E. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Balick, Bruce [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Carollo, Marcella [Department of Physics, ETH-Zurich, Zurich 8093 (Switzerland); Disney, Michael J. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Frogel, Jay A. [Association of Universities for Research in Astronomy, Washington, DC 20005 (United States); Hall, Donald [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Holtzman, Jon A. [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Kimble, Randy A. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); McCarthy, Patrick J. [Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101-1292 (United States); O'Connell, Robert W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Paresce, Francesco [Istituto di Astrofisica Spaziale e Fisica Cosmica, INAF, Via Gobetti 101, 40129 Bologna (Italy); Saha, Abhijit [National Optical Astronomy Observatories, Tucson, AZ 85726-6732 (United States); Silk, Joseph I. [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Trauger, John T. [NASA-Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Walker, Alistair R., E-mail: wpb@pha.jhu.edu [Cerro Tololo Inter-American Observatory, La Serena (Chile)

2011-04-10

298

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)

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.

Kirchner, H. P.

1974-01-01

299

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

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.

Green, R.D.; Gilbert, H.R.

1983-01-01

300

Identification of character-impact odorants in coriander and wild coriander leaves using gas chromatography-olfactometry (GCO) and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC x GC-TOFMS).  

PubMed

The essential oil of coriander leaves (Coriandrum sativum) and wild coriander leaves (Eryngium foetidum) grown in Fiji was obtained by steam distillation. The aroma profiles were characterised using gas chromatography-olfactometry (GCO) and CharmAnalysis. The character-impact odorants were identified using comprehensive two-dimensional gas chromatography (GC x GC) combined with time-of-flight mass spectrometry (TOFMS). During GCO analysis, the co-elution of E-2-alkenals and E-2-alken-1-ols resulted in the perception of 'odour-clusters'. The most important odorants in C. sativum were found to be Z-2-decenal, a co-eluting odour-cluster (E-2-dodecenal, E-2-dodecen-1-ol, and 1-dodecanol), beta-ionone, eugenol, and E-2-decenal. E-2-decen-1-ol was the most abundant compound in C. sativum (26.0% TIC) but only contributed 0.39% of the total odour activity. The most abundant compound in E. foetidum was E-2-dodecenal (63.5% TIC), which also contributed the most odour activity (52.9%). Other important odorants were either eugenol or a trimethylbenzaldehyde isomer, beta-ionone, Z-4-dodecenal, dodecanal, and E-2-tetradecenal. GC x GC-TOFMS allowed the identification of 42 and 20 compounds not previously reported in the literature for C. sativum and E. foetidum, respectively. In particular, beta-ionone was determined to be an important odorant in both samples but could not be identified with GC-qMS. PMID:16013833

Eyres, Graham; Dufour, Jean-Pierre; Hallifax, Gabrielle; Sotheeswaran, Subramaniam; Marriott, Philip J

2005-06-01

301

The impact of wet flue gas desulfurization scrubbing on mercury emissions from coal-fired power stations  

SciTech Connect

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.

Stephen Niksa; Naoki Fujiwara [Niksa Energy Associates, Belmont, CA (US)

2005-07-01

302

Impact of the BEA zeolite morphology on isobutane adsorption followed by Reversed-Flow Inverse Gas Chromatography.  

PubMed

The mass transfer phenomena of isobutane (i-C4) were investigated at 343K on three protonic BEA zeolites. Defined by their crystallites sizes and degrees of aggregation, these samples were characterized by Reversed-Flow Inverse Gas Chromatography (RF-GC). This simple technique, used in conjunction with numerical computation, allowed the determination of physicochemical quantities like local monolayer capacities, probability density functions and diffusion coefficients in a time-resolved way. This study enabled to conclude that the effective diffusion coefficient was affected by the size of the zeolite agglomerate whereas the surface diffusion depended on the zeolite crystallite size. PMID:22964049

Batalha, N; Soualah, A; Pinard, L; Pouilloux, Y; Lemos, F; Belin, T

2012-10-19

303

Vesiculation, melt formation, noble gas/nitrogen behaviour, and impact chronology on a planetary regolith : the case of Benccubbin (CB) meteorite  

NASA Astrophysics Data System (ADS)

The Benccubbin meteorite is a member of the CB peculiar meteorite family, which all have reduced silicates, metal zoning, solar Ni/Co and large enrichments in 15N, that have been regarded as relics of their very primitive character. However, these meteorites also show tugsten isotopic ratios suggesting metal differentiation events several Ma after start of solar system formation. The Benccubbin mineralogy is best explained as being an heterogeneous planetary regolith containing clasts of different origins (e.g., CO, CI chondrules and clasts, silicates of unknown origin). This meteorite presents evidence of having been impacted, such as melt, temperature gradient recorded at the silicate/metal interface, and textures indicative of rapid cooling. Notably, Benccubbin contains vesicles in several phases : partially molten silicate clasts and CO chondrules, impact melt, and the so-called bubble grains 1. We have analysed several Benccubbin mineral and metal phases for N and noble gas isotopes and abundances by both laser fusion and vacuum crushing. 15N-rich nitrogen (d15N up to +1,000 per mil) is ubiquituous, particularly inside vesicles, and is associated with noble gases. Notably, N and noble gases appear to have largely exchanged between silicate and vesicles, reaching locally equilibrium partitioning. Gases are still released after extensive crushing up to 4,000 strokes, in contrast to the case of MORB glasses and suggesting a foam-like, decompression structure of the impacted melt. N and Ar correlate well, showing that the N solubility was comparable to that of Ar and therefore that the redox conditions were above IW, according to 2. From the N content of the glass, we estimate that it equilibrated with a vapor plume in which the pressure of nitrogen was ~300 Bar. Radiogenic 40Ar is present inside the vesicles, showing that the vesiculation event was not an early process. Ar-Ar dating of Benccubbin suggests involvement in an impact around 4.2 Ga. In contrast to very variable N and primordial noble gas contents among different phases, cosmogenic 3He, 21Ne and 38Ar abundances are uniform, and vesicles contain little cosmogenic isotopes, showing that space exposure occurred after the vesicle forming impact event. Hence the event that led to the ejection of the Benccubbin meteorite was distinct from the vesiculation one, and occurred 40-50 Ma ago according to cosmogenic 3He, 21Ne and 38Ar isotopes and 38Ar-37Ar correlation. Noble gases have been well preserved in vesicles from cosmic ray isotope contributions, permitting to determine their origin precisely despite extensive exposure in space. Noble gases present Q-like isotopic ratios but highly fractionated abundances with respect to Q. The fact that comets are definitely rich in 15N 3 and may also have Q-like noble gas signature in their refractory phases 4 is suggestive of a possible link between cometary matter and CBs. 1. Perron, C., Fieni, C. and Guilhaumou, N. Geochim.Cosmochim. Acta 72, 959-977 (2008). 2. Libourel, G., Marty, B. and Humbert, F. Geochim. Cosmochim. Acta 67, 4123-4135 (2003). 3. Bockelee-Morvan, D. et al. Large excess of heavy nitrogen in both hydrogen cyanide and cyanogen from comet 17P/Holmes. Ap J.679, L49-L52 (2008). 4. Marty, B. et al. Science 319, 75-78 (2008).

Marty, B.; Turner, G.; Kelley, S. P.

2008-12-01

304

Effect of placements (horizontal with vertical) on gas-solid flow and particle impact erosion in gate valve  

NASA Astrophysics Data System (ADS)

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 250?m.

Lin, Zhe; Zhu, Linhang; Cui, Baoling; Li, Yi; Ruan, Xiaodong

2014-12-01

305

CO2 injectivity in saline aquifers: The impact of non-Darcy flow, phase miscibility, and gas compressibility  

NASA Astrophysics Data System (ADS)

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.

Mijic, Ana; LaForce, Tara C.; Muggeridge, Ann H.

2014-05-01

306

Potential impacts of electric power production utilizing natural gas, renewables and carbon capture and sequestration on US Freshwater resources.  

PubMed

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

Tidwell, Vincent C; Malczynski, Leonard A; Kobos, Peter H; Klise, Geoffrey T; Shuster, Erik

2013-08-01

307

DAYCENT Model Projections of Land Use Change Impacts on N Gas Emissions in the Central US (Invited)  

NASA Astrophysics Data System (ADS)

Nitrogen additions to cropped soils from fertilizers and symbiotic N fixation are an important source of N2O, NOx, and NH3 emissions. As the need for biofuel feedstock increases, pasture, prairie, and other lands are being converted to biofuel cropping systems. We used the DAYCENT biogeochemical model to quantify emission patterns of N gas related aerosol precursors under current land use and land use changes. DAYCENT is the daily time step version of the CENTURY model and simulates plant growth, soil organic matter decomposition, and the microbial processes that result in N gas emissions. Land use change scenarios considered include conversion of current cropland, pasture, CRP, and abandoned crop land to different biofuel cropping systems under conventional and improved management scenarios. Model results suggest that conversion of cropland to corn ethanol cropping would result in a small increase in emissions but use of improved fertilizers would mitigate this increase. Conversion of pasture, CRP, and abandoned crop land to corn ethanol cropping results in substantial increases in emissions that would only be partially mitigated by using improved fertilizers. However, converting these non-cropped lands to cellulosic biofuel cropping systems, such as switchgrass and miscanthus, would result in a more modest increase in emissions. Converting land already used for cropping to cellulosic biofuel crops would likely result in a decrease in emissions. We conclude that previous land use interacts with current land management strategies to control emissions.

Del Grosso, S.; Parton, W. J.; Ogle, S. M.

2009-12-01

308

Determination of geosmin and 2-methylisoborneol in water using solid-phase microextraction and gas chromatography-chemical ionisation/electron impact ionisation-ion-trap mass spectrometry.  

PubMed

A method for the determination of geosmin and 2-methylisoborneol (MIB) in water by solid-phase microextraction (SPME) is presented. Various SPME fibre chemistries have been compared for their efficiency in extracting MIB from water. Extraction conditions including the extraction time and temperature have been optimised. A 30 ml water sample is extracted for 20 min at 60 degrees C using a divinylbenzene fibre, and the extract analysed by gas chromatography with ion-trap mass spectrometry detection. d5-Geosmin and d3-MIB are added as internal standards to compensate for any variability in the SPME process which is not carried out to equilibrium. Chemical ionisation, using acetonitrile as the reagent gas, was found to give superior sensitivity to electron impact ionisation (EI) for the detection of MIB. EI was used as the ionisation mode for detection of geosmin. The method shows good linearity over the concentration range 5-40 ng l-1 and gives detection limits of 1 ng l-1 for both geosmin and MIB. Recovery (93-110%) and precision (3-12%) over this concentration range, for both raw and treated drinking waters, are comparable to currently employed methods such as closed-loop stripping analysis (CLSA). The method offers the advantage of being simple to use, with much shorter analysis times in comparison to CLSA. PMID:10209901

McCallum, R; Pendleton, P; Schumann, R; Trinh, M U

1998-10-01

309

Explicit Finite Element Modeling of Multilayer Composite Fabric for Gas Turbine Engine Containment Systems, Phase II. Part 2; Ballistic Impact Testing  

NASA Technical Reports Server (NTRS)

This report summarizes the ballistic impact testing that was conducted to provide validation data for the development of numerical models of blade-out events in fabric containment systems. The ballistic impact response of two different fiber materials - Kevlar(TradeName) 49 and Zylon(TradeName) AS (as spun) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation, and velocity of the projectile were varied and recorded. In most cases, the tests were designed so the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models to predict the response of fabrics under conditions that simulate those of a jet engine blade-release situation. In addition, some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different fabric materials.

Revilock, D. M.; Pereira, J. M.

2009-01-01

310

First controlled sub-seabed CO2 release experiment: Insights into gas migration pathways and impacts on sediment physical properties  

NASA Astrophysics Data System (ADS)

Carbon Capture and Storage (CCS) is a key technology to potentially mitigate global warming by reducing the amount of carbon dioxide (CO2) from industrial facilities and power generation that escapes into the atmosphere. In order to broaden the usage of geological storage as a safe and reliable climate change mitigation option, it is vital to understand CO2 behaviour after its injection within a storage reservoir, including its migration through overlying sediments, as well as its biogeochemical and ecological impacts in the event of leakage at the seafloor. To address these issues, the first controlled CO2 release experiment, entitled 'Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage (QICS)', took place in Ardmucknish Bay, Oban, in May-July 2012. This experiment involved the injection of CO2 of known flux under shallow unconsolidated marine sediments over 36 days and repeated monitoring using geophysical and geochemical techniques. High resolution seismic reflection data (chirp and boomer), covering both pre-release and release stages, allows the detection of various CO2-related anomalies including seismic chimneys, enhanced reflectors within the sediment overburden and bubbles into the overlying water column. CO2 migration pattern is predominantly controlled by the stratigraphy in the early stages of the experiment. However, the increasing flow rate becomes the dominant factor determining CO2 migration, towards the end of the experiment. In addition, analysis of reflection coefficients and seismic attenuation indicates the effect of CO2 on sediment physical properties.

Cevatoglu, M.; Bull, J. M.; Vardy, M. E.; Wright, I. C.; Gernon, T. M.

2013-12-01

311

The ionizing fluxes of early type stars and their impact on HII regions and the `Diffuse Ionized Gas'  

E-print Network

We discuss recent results on the ionizing fluxes of O stars obtained from our "combined stellar structure and atmosphere models" (CoStar) accounting for stellar winds, non-LTE effects and line blanketing. The implications on the ionization structure of HII regions are summarized, and observational constraints on the ionizing spectra and the total ionizing photon fluxes are presented. Using our CoStar models we derive new consistent predictions for the H and HeI ionizing fluxes of steady-state massive star populations. Implications for the interpretation of observations of `Diffuse Ionized Gas' in galaxies are discussed. Finally we present preliminary model calculations aiming to improve our current predictions further and compare our results to recent results from the Munich group.

Daniel Schaerer

1997-10-08

312

A Model Study of the Impact of Source Gas Changes on the Stratosphere for 1850-2100  

NASA Technical Reports Server (NTRS)

The long term stratospheric impacts due to emissions of CO2, CH4, N2O, and ozone depleting substances (ODSs) are investigated using an updated version of the Goddard two-dimensional (2D) model. Perturbation simulations with the ODSs, CO2, CH4, and N2O varied individually are performed to isolate the relative roles of these gases in driving stratospheric changes over the 1850-2100 time period. We also show comparisons with observations and the God- 40 dard Earth Observing System chemistry-climate model simulations for the time period 1970-2100 to illustrate that the 2D model captures the basic processes responsible for longterm stratospheric change. The 2D simulations indicate that prior to 1940, the 45 ozone increases due to CO2 and CH4 loading outpace the ozone losses due to increasing N2O and carbon tetrachloride (CCl4) emissions, so that ozone reaches a broad maximum during the 1920s-1930s. This preceeds the significant ozone depletion during approx. 1960-2050 driven by the ODS loading. During the latter half of the 21st century as ODS emissions diminish, CO2, N2O, and CH4 loading will all have significant impacts on global total ozone based on the IPCC AIB (medium) scenario, with CO2 having the largest individual effect. Sensitivity tests illustrate that due to the strong chemical interaction between methane and chlorine, the CH4 impact on total ozone becomes significantly more positive with larger ODS loading. The model simulations also show that changes in stratospheric temperature, Brewer-Dobson circulation (BDC), and age of air during 1850-2100 are controlled mainly by the CO2 and ODS loading. The simulated acceleration of the BDC causes the age of air to decrease by approx. 1 year from 1860-2100. The corresponding photochemical lifetimes of N2O, CFCl3, CF2Cl2, and CCl4 decrease by 11-13% during 1960-2100 due to the acceleration of the BDC, with much smaller lifetime changes 4%) caused by changes in the photochemical loss rates.

Fleming, E. L.; Jackman, C. H.; Stolarski, R. S.; Douglass, A. R.

2011-01-01

313

Updating the lake-atmosphere gas transfer velocity with impacts on the role of lake ecosystems in global carbon cycling  

NASA Astrophysics Data System (ADS)

Currently, the global estimate for the amount of carbon bound in terrestrial ecosystems is 3.0 × 0.9 Pg C y-1 [Le Quéré et al., 2009]. Lakes are not explicitly included in currently used global carbon models [Randall et al., 2007] but it has been estimated that the global net CO2 flux from lakes to the atmosphere range from 0.07 to 0.15 Pg C y-1 [Cole et al., 2007], corresponding to 2.3-5.0% of the total average terrestrial net uptake of carbon. These lake flux estimates may be considerably biased [MacIntyre et al., 2010], since although the data pertain to about 5000 lakes throughout the world [Sobek and Tranvik, 2005], the estimates are not from direct flux measurements. Instead, they are based on surface-water CO2 partial pressure in combination with the gas transfer velocity, k. The uncertainty in the global net CO2 flux is mostly due to the uncertainties in k, which can vary considerably. Cole and Caraco (1998) measured a range of 1.4 to 4.8 cm h-1 for k, but again, these values are not based on direct flux measurements of CO2. The most widely used empirical models of k have wind speed as the only explaining variable. However, the gas transfer velocity is also known to depend on turbulence in the surface water [MacIntyre et al., 2010], which in turn depends mostly on penetrative water convection at low wind conditions [MacIntyre et al., 2010; MacIntyre et al., 2001] - the conditions often prevailing in lakes [Schladow et al., 2002]. We formulated an improved model for k with heat flux parameterization in addition to a wind-speed parameter, determined from an analysis of 4 months (August - November 2011) of continuous high-frequency data in a typical small boreal lake in southern Finland. The CO2 flux from the lake to the atmosphere, atmospheric partial pressure of CO2, and latent and sensible heat were measured with the EC technique installed on a platform. Ancillary measurements included surface-water CO2 concentration and temperature, and net longwave and shortwave radiation. The modeled average k for the whole period, 9.5 cm h-1, was near to the measured average, 8.7 cm h-1. We used 24-hour averages when comparing the results. The new model for k had an R2 value of 0.66 when its performance was compared to the measured gas transfer velocity. Even though this is a lot higher value than when comparing the measured k with a widely used model for k (Cole and Caraco 1998, R2=0.29), the new model could not predict all the sudden changes in k and still roughly one third of the variation was left unexplained. This might be due to the environmental factors omitted by the model, e.g. surfactants. As a result, we showed that the current estimate of the global net CO2 flux from lakes to the atmosphere triples from 0.07-0.15 Pg C y-1 to 0.23-0.48 Pg C y-1 when the average k by Cole and Caraco (1998) is replaced with the new k. This corresponds to 7.5-16.0% of the total CO2 bound in terrestrial ecosystems compared with the current estimates of 2.3-5.0%. The new parameterization of k, assuming that it represents lakes in general, thus shows that the role of lakes in the global carbon cycle has been heavily underestimated and emphasizes the explicit inclusion of lakes in global carbon models.

Heiskanen, J. J.; Mammarella, I.; Haapanala, S.; Vesala, T.; Pumpanen, J. S.; Ojala, A.

2013-12-01

314

MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM - PRELIMINARY REPORT  

SciTech Connect

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 c

Zamecnik, J.; Choi, A.

2009-03-25

315

Impact of oxidation catalysts on exhaust NO2/NOx ratio from lean-burn natural gas engines.  

PubMed

Oxides of nitrogen (NOx) emitted from internal combustion engines are composed primarily of nitric oxide (NO) and nitrogen dioxide (NO2). Exhaust from most combustion sources contains NOx composed primarily of NO. There are two important scenarios specific to lean-burn natural gas engines in which the NO2/NOx ratio can be significant: (1) when the engine is operated at ultralean conditions and (2) when an oxidation catalyst is used. Large NO2/NOx ratios may result in additional uncertainty in NOx emissions measurements because the most common technique (chemiluminescence) was developed for low NO2/NOx ratios. In this work, scenarios are explored in which the NO2/NOx ratio can be large. Additionally, three NOx measurement approaches are compared for exhaust with various NO2/NOx ratios. The three measurement approaches are chemiluminescence, chemical cell, and Fourier-transform infrared spectroscopy. A portable analyzer with chemical cell technology was found to be the most accurate for measuring exhaust NOx with large NO2/NOx ratios. PMID:20681434

Olsen, Daniel B; Kohls, Morgan; Arney, Gregg

2010-07-01

316

Assessing impacts of unconventional natural gas extraction on microbial communities in headwater stream ecosystems in Northwestern Pennsylvania  

PubMed Central

Hydraulic fracturing and horizontal drilling have increased dramatically in Pennsylvania Marcellus shale formations, however the potential for major environmental impacts are still incompletely understood. High-throughput sequencing of the 16S rRNA gene was performed to characterize the microbial community structure of water, sediment, bryophyte, and biofilm samples from 26 headwater stream sites in northwestern Pennsylvania with different histories of fracking activity within Marcellus shale formations. Further, we describe the relationship between microbial community structure and environmental parameters measured. Approximately 3.2 million 16S rRNA gene sequences were retrieved from a total of 58 samples. Microbial community analyses showed significant reductions in species richness as well as evenness in sites with Marcellus shale activity. Beta diversity analyses revealed distinct microbial community structure between sites with and without Marcellus shale activity. For example, operational taxonomic units (OTUs) within the Acetobacteracea, Methylocystaceae, Acidobacteriaceae, and Phenylobacterium were greater than three log-fold more abundant in MSA+ sites as compared to MSA? sites. Further, several of these OTUs were strongly negatively correlated with pH and positively correlated with the number of wellpads in a watershed. It should be noted that many of the OTUs enriched in MSA+ sites are putative acidophilic and/or methanotrophic populations. This study revealed apparent shifts in the autochthonous microbial communities and highlighted potential members that could be responding to changing stream conditions as a result of nascent industrial activity in these aquatic ecosystems. PMID:25408683

Trexler, Ryan; Solomon, Caroline; Brislawn, Colin J.; Wright, Justin R.; Rosenberger, Abigail; McClure, Erin E.; Grube, Alyssa M.; Peterson, Mark P.; Keddache, Mehdi; Mason, Olivia U.; Hazen, Terry C.; Grant, Christopher J.; Lamendella, Regina

2014-01-01

317

Feebates and Fuel Economy Standards: Impacts on Fuel Use in Light-Duty Vehicles and Greenhouse Gas Emissions  

SciTech Connect

This study evaluates the potential impacts of a national feebate system, a market-based policy that consists of graduated fees on low-fuel-economy (or high-emitting) vehicles and rebates for high-fuel-economy (or lowemitting) vehicles. In their simplest form, feebate systems operate under three conditions: a benchmark divides all vehicles into two categories-those charged fees and those eligible for rebates; the sizes of the fees and rebates are a function of a vehicle's deviation from its benchmark; and placement of the benchmark ensures revenue neutrality or a desired level of subsidy or revenue. A model developed by the University of California for the California Air Resources Board was revised and used to estimate the effects of six feebate structures on fuel economy and sales of new light-duty vehicles, given existing and anticipated future fuel economy and emission standards. These estimates for new vehicles were then entered into a vehicle stock model that simulated the evolution of the entire vehicle stock. The results indicate that feebates could produce large, additional reductions in emissions and fuel consumption, in large part by encouraging market acceptance of technologies with advanced fuel economy, such as hybrid electric vehicles.

Greene, David L [ORNL

2011-01-01

318

Assessing impacts of unconventional natural gas extraction on microbial communities in headwater stream ecosystems in Northwestern Pennsylvania.  

PubMed

Hydraulic fracturing and horizontal drilling have increased dramatically in Pennsylvania Marcellus shale formations, however the potential for major environmental impacts are still incompletely understood. High-throughput sequencing of the 16S rRNA gene was performed to characterize the microbial community structure of water, sediment, bryophyte, and biofilm samples from 26 headwater stream sites in northwestern Pennsylvania with different histories of fracking activity within Marcellus shale formations. Further, we describe the relationship between microbial community structure and environmental parameters measured. Approximately 3.2 million 16S rRNA gene sequences were retrieved from a total of 58 samples. Microbial community analyses showed significant reductions in species richness as well as evenness in sites with Marcellus shale activity. Beta diversity analyses revealed distinct microbial community structure between sites with and without Marcellus shale activity. For example, operational taxonomic units (OTUs) within the Acetobacteracea, Methylocystaceae, Acidobacteriaceae, and Phenylobacterium were greater than three log-fold more abundant in MSA+ sites as compared to MSA- sites. Further, several of these OTUs were strongly negatively correlated with pH and positively correlated with the number of wellpads in a watershed. It should be noted that many of the OTUs enriched in MSA+ sites are putative acidophilic and/or methanotrophic populations. This study revealed apparent shifts in the autochthonous microbial communities and highlighted potential members that could be responding to changing stream conditions as a result of nascent industrial activity in these aquatic ecosystems. PMID:25408683

Trexler, Ryan; Solomon, Caroline; Brislawn, Colin J; Wright, Justin R; Rosenberger, Abigail; McClure, Erin E; Grube, Alyssa M; Peterson, Mark P; Keddache, Mehdi; Mason, Olivia U; Hazen, Terry C; Grant, Christopher J; Lamendella, Regina

2014-01-01

319

Impact of wildfire emissions on trace gas and aerosol concentration measured at the Zotino Tall Tower Observatory (ZOTTO) in Central Siberia  

NASA Astrophysics Data System (ADS)

Boreal wildfires are large sources of reactive trace gases and aerosols to the atmosphere, accounting for 20% of carbon emissions from global biomass burning. Siberian wildfires are a major extratropical source of carbon monoxide (CO), as well as a significant source of black carbon, smoke aerosols, and other climate-relevant atmospheric gas/particle species. Smoke particles released by Siberian wildfires could be tracked thousands of kilometers downwind in the entire Northern Hemisphere, perturbing regional to global radiation budgets by influencing light scattering and cloud microphysical processes. The boreal regions of the Northern Hemisphere are expected to experience the largest temperature increases, which will likely increase the severity and frequency of fires. Consequently, long-term continuous trace gas and aerosol measurements in central Siberia are vital for assessing the atmospheric impact of Siberian boreal fires on regional to global air quality and climate. Since 2006, the Zotino Tall Tower Facility (ZOTTO; www.zottoproject.org), a unique international research platform for large-scale climatic observations, is operational about 20 km west of the Yenisei river (60.8°N; 89.35°E). A 300 m-tall tower allows regular probing of the mixed part of the boundary layer, which is only moderately influenced by diurnal variations of local surface fluxes and thus, in comparison with surface layer, representative for a larger region. Our investigation of the wildfires' impact on surface air composition in Central Siberia is based on four years of CO/CO2/CH4 and aerosol particle mass data measured at 300 m a.g.l.. Episodes of atmospheric transport from wildfires upwind of the measurements site are identified based on ensembles of HYSPLIT backward trajectories and MODIS active fire products. The emission factors are calculated using the Carbon Mass Balance method. In an effort to simplify combustion to its most fundamental principles, the combustion efficiency (CE) is used to represent the completeness of combustion. The following general notion is applied: if the CE exceeds 90 %, a fire is typically in the flaming phase, whereas if CE is less than 85 % combustion is in the smoldering phase. Most fires can be considered as being in a "mixed" phase. Ideally, the emission ratios can be obtained by dividing the excess concentrations of trace gas species measured in a fire plume (e.g. CO, CO2) by the excess concentration of a measured reference gas from the data set. Ground-based CO and CO2 measurements in plumes from relatively distant fires can usually not be used to extract CO/CO2 emission ratios due to the uncertain contributions of biogenic CO2 from respiration to the plume air. We present our attempt to extract CO/CO2 relationships related to sources from statistical analysis of our data set. The burnt biomass load is taken from the Global Land Cover 2000 project and validated by our in situ data set. Finally, episodes of emissions from the wildfires identified at the given location and time are calculated with a simple bottom-up approach using the equation of Seiler and Crutzen.

Panov, A.; Chi, X.; Winderlich, J.; Birmili, W.; Lavri?, J. V.; Andreae, M. O.

2012-04-01

320

MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM-PRELIMINARY REPORT  

SciTech Connect

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 c

Zamecnik, J.; Choi, A.

2010-08-18

321

Modeling Impacts of Alternative Practices on Net Global Warming Potential and Greenhouse Gas Intensity from Rice–Wheat Annual Rotation in China  

PubMed Central

Background Evaluating the net exchange of greenhouse gas (GHG) emissions in conjunction with soil carbon sequestration may give a comprehensive insight on the role of agricultural production in global warming. Materials and Methods Measured data of methane (CH4) and nitrous oxide (N2O) were utilized to test the applicability of the Denitrification and Decomposition (DNDC) model to a winter wheat – single rice rotation system in southern China. Six alternative scenarios were simulated against the baseline scenario to evaluate their long-term (45-year) impacts on net global warming potential (GWP) and greenhouse gas intensity (GHGI). Principal Results The simulated cumulative CH4 emissions fell within the statistical deviation ranges of the field data, with the exception of N2O emissions during rice-growing season and both gases from the control treatment. Sensitivity tests showed that both CH4 and N2O emissions were significantly affected by changes in both environmental factors and management practices. Compared with the baseline scenario, the long-term simulation had the following results: (1) high straw return and manure amendment scenarios greatly increased CH4 emissions, while other scenarios had similar CH4 emissions, (2) high inorganic N fertilizer increased N2O emissions while manure amendment and reduced inorganic N fertilizer scenarios decreased N2O emissions, (3) the mean annual soil organic carbon sequestration rates (SOCSR) under manure amendment, high straw return, and no-tillage scenarios averaged 0.20 t C ha?1 yr?1, being greater than other scenarios, and (4) the reduced inorganic N fertilizer scenario produced the least N loss from the system, while all the scenarios produced comparable grain yields. Conclusions In terms of net GWP and GHGI for the comprehensive assessment of climate change and crop production, reduced inorganic N fertilizer scenario followed by no-tillage scenario would be advocated for this specified cropping system. PMID:23029173

Wang, Jinyang; Zhang, Xiaolin; Liu, Yinglie; Pan, Xiaojian; Liu, Pingli; Chen, Zhaozhi; Huang, Taiqing; Xiong, Zhengqin

2012-01-01

322

Impacts of rice varieties and management on yield-scaled greenhouse gas emissions from rice fields in China: a meta-analysis  

NASA Astrophysics Data System (ADS)

Increasing numbers of studies have suggested that a comprehensive assessment of the impacts of cropping practices on greenhouse gas (GHG) emissions per unit yield (yield-scaled), rather than by land area (area-scaled), is needed to inform trade-off decisions to increase yields and reduce GHG emissions. We conducted a meta-analysis to quantify impacts of rice varieties on the global warming potential (GWP) of GHG emissions at the yield scale in China. The results showed that significantly higher yield-scaled GWP occurred with indica rice varieties (1101.72 kg CO2 equiv. Mg-1) compared to japonica rice varieties (711.38 kg CO2 equiv. Mg-1). Lower yield-scaled GHG emissions occurred within 120-130 days of growth duration after transplanting (GDAT; 613.66 kg CO2 equiv. Mg-1), followed by 90-100 days of GDAT (749.72 kg CO2 equiv. Mg-1), 100-110 days of GDAT (794.29 kg CO2 equiv. Mg-1), and 70-80 days of GDAT (800.85 kg CO2 equiv. Mg-1). The greatest reduction, 41%, occurred at a rate of 150-200 kg N ha-1 relative to the non-fertilized control. Consequently, appropriate cultivar choice and pairs was of vital importance in the rice cropping system. A further life cycle assessment of GHG emissions among rice varieties at the yield scale is urgently needed to develop win-win policies for rice production to achieve higher yield with lower emissions.

Zheng, H.; Huang, H.; Yao, L.; Liu, J.; He, H.; Tang, J.

2013-12-01

323

Impacts of rice varieties and management on yield-scaled greenhouse gas emissions from rice fields in China: A meta-analysis  

NASA Astrophysics Data System (ADS)

Increasing numbers of studies have suggested that a comprehensive assessment of the impacts of cropping practices on greenhouse gas (GHG) emissions per unit yield (yield-scaled), rather than by land area (area-scaled), is needed to inform trade-off decisions to increase yields and reduce GHG emissions. We conducted a meta-analysis to quantify impacts of rice varieties on the global warming potential (GWP) of GHG emissions at the yield scale in China. Our results showed that significantly higher yield-scaled GWP occurred with indica rice varieties (1101.72 kg CO2 equiv. Mg-1) than japonica rice varieties (711.38 kg CO2 equiv. Mg-1). Lower yield-scaled GHG emissions occurred within 120-130 days of growth duration after transplanting (GDAT; 613.66 kg CO2 equiv. Mg-1), followed by 90-100 days of GDAT (749.72 kg CO2 equiv. Mg-1, 100-110 days of GDAT (794.29 kg CO2 equiv. Mg-1), and 70-80 days of GDAT (800.85 kg CO2 equiv. Mg-1). The fertilizer rate of 150-200 kg N ha-1 resulted in the lowest yield-scaled GWP. Consequently, appropriate cultivar choice and pairs were of vital importance in the rice cropping system. A further life cycle assessment of GHG emissions among rice varieties at the yield scale is urgently needed to develop win-win policies for rice production to achieve higher yield with lower emissions.

Zheng, H.; Huang, H.; Yao, L.; Liu, J.; He, H.; Tang, J.

2014-07-01

324

Comparative evaluation of liquid chromatography–mass spectrometry versus gas chromatography–mass spectrometry for the determination of hexabromocyclododecanes and their degradation products in indoor dust  

Microsoft Academic Search

Domestic and office dust samples (n=37) were analyzed for hexabromocyclododecanes (HBCDs) using gas chromatography–electron-capture negative ionization–mass spectrometry (GC–ECNI\\/MS) and liquid chromatography–electrospray tandem mass spectrometry (LC–ESI\\/MS\\/MS). To determine the best method to quantify HBCDs using GC–ECNI\\/MS, BDE 128 was used as internal standard (I.S.) in all samples, while 13C-labeled ?-HBCD was used as I.S. in some samples. Total HBCD concentrations (sum

Mohamed Abou-Elwafa Abdallah; Catalina Ibarra; Hugo Neels; Stuart Harrad; Adrian Covaci

2008-01-01

325

Offshore oil & gas markets heating up: Gulf of Mexico rising from `Dead Sea` image; healthy Gulf, North Sea markets combine for big impact  

SciTech Connect

Only three years ago, Gulf of Mexico drilling activity was so moribund that it was termed the Dead Sea. But the market has changed so there is now effectively 100 percent utilization in several important categories of offshore rigs, and almost every type of offshore rig is now getting higher use and better rates. What makes these changes so profound is that few industry participants saw this tightness developing, and almost no one predicted that it would occur so soon. Even the largest offshore contractors were pleasantly surprised as they watched their key drilling markets tighten so uickly after many years of vast oversupply. Today, while neither the Gulf of Mexico nor the North Sea could be described as booming, they are not falling apart either. The combination of both markets merely being normal at the same time has made a big impact on the worldwide supply and demand for offshore drilling. The need for steady and increasing offshore oil and gas production has never been so high. The technology now in place is allowing the development of offshore areas deemed almost impossible less than a decade ago. Also, the vast excess supply of offshore equipment is gone for many forms of drilling, and the need for steadily higher dayrates is real and will merely increase over time.

Simmons, M.R.

1995-09-01

326

Assessing economic impacts to coastal recreation and tourism from oil and gas development in the Oregon and Washington Outer Continental Shelf. Inventory and evaluation of Washington and Oregon coastal recreation resources  

SciTech Connect

The purpose of the three-part study was to assist Materials Management Service (MMS) planners in evaluation of the anticipated social impact of proposed oil and gas development on the environment. The purpose of the report is primarily to analyze the econometric models of the Dornbusch study. The authors examine, in detail, key aspects of the gravity, consumer surplus, and economic effects (input-output) models. The purpose is two-fold. First, the authors evaluate the performance of the model in satisfying the objective for which it was developed: analyzing economic impacts of OCS oil and gas development in California. Second, the authors evaluate the applicability of the modeling approach employed in the Dornbusch study for analyzing potential OCS development impacts in Washington and Oregon. At the end of the report, the authors offer suggestions for any future study of economic impacts of OCS development in Washington and Oregon. The recommendations concern future data gathering procedures and alternative modeling approaches for measuring economic impacts.

Ellis, G.M.; Johnson, N.S.; Chapman, D.

1991-05-01

327

[A case of chloropicrin detection by purge and trap gas chromatography/mass spectrometry].  

PubMed

Chloropicrin (CP) is an agricultural chemical used as insecticide or fungicide, which occasionally causes accidental poisoning and may used in criminal cases including suicide and homicide. Although CP is usually analyzed using gas chromatography/electron capture detection technique (GC/ECD), further identification by gas chromatography/mass spectrometry (GC/MS) may be required from the view point of forensic chemistry and also clinical toxicology. However, it is very difficult to detect a trace of CP by routine GC/MS. The present paper describes a criminal case, in which GC/MS equipped with curie point purge and trap sampler was successfully applied to detect a small amount of CP. PMID:14582358

Ishizawa, Fujio; Ishiwata, Tetsuya; Miyata, Katsufumi; Yoshida, Tsutomu

2003-07-01

328

Improvement of a ``mini'' two-stage light-gas gun for hypervelocity impact experiments: Technical devices to accelerate and detect a ``minute'' projectile efficiently  

Microsoft Academic Search

A gas-gun system was improved and optimized in order to obtain higher projectile velocity. The gas gun used in this study was a ``mini'' two-stage light-gas gun suitable for the acceleration of a ``minute'' projectile. As a major improvement in the mini gun, the high-pressure coupler was divided into two parts. One part was a generation section of the hot

Fumikazu Saito; Toshitika Usui; Hideki Tamura; Yusuke Tanaka; Michiaki Shimizu; Ken-Ichi Kondo

2005-01-01

329

Modeling gas dissolution in deepwater oil/gas spills  

NASA Astrophysics Data System (ADS)

Gases in deepwater oil/gas spills can lose considerable amounts of the gas phase due to dissolution in water. Gas dissolution has a significant impact on the behavior of the oil/gas jet/plume because of its impact on the buoyancy. A method is presented in this paper for computing gas dissolution that covers a broad range of water depth, from shallow water where gases behave as ideal ones under low pressure to deepwater where gases behave as non-ideal ones under high pressures. The method presented also accounts for the spherical and non-spherical shapes of gas bubbles. The gas dissolution computations are validated by comparing the computed results with observed data from previously conducted laboratory experiments. The gas dissolution computation module is then integrated with a model for underwater oil/gas jets/plumes by Yapa and Zheng [J. Hydraul. Res. 35 (5) (1997) 673]. Scenario simulations are presented to show the impacts of gas dissolution on the behavior of jets/plumes. These scenarios show the impact of dissolution on the behavior of the jet/plume. The comparison of results using ideal gas conditions and non-ideal gas conditions is also shown.

Zheng, Li; Yapa, Poojitha D.

2002-01-01

330

Impact of Gas-Phase Mechanisms on Weather Research Forecasting Model with Chemistry (WRF/Chem) Predictions: Mechanism Implementation and Comparative Evaluation  

EPA Science Inventory

Gas-phase mechanisms provide important oxidant and gaseous precursors for secondary aerosol formation. Different gas-phase mechanisms may lead to different predictions of gases, aerosols, and aerosol direct and indirect effects. In this study, WRF/Chem-MADRID simulations are cond...

331

Gas transport of oil: It`s impact on sealing and the development of secondary porosity. Annual report, July 1994June 1995  

Microsoft Academic Search

Laboratory experiments were completed that show gas capillary sealing can produce completely impermeable zones in strata with multiple sand-shale interfaces. Evidence has been assembled that indicates gas-capillary phenomena are responsible for sealing in the offshore Louisiana Gulf Coast and that these seals exert a fundamental and predictable control on basin fluid flow. The pressure transition zone contains a sufficient number

Cathles

1996-01-01

332

A study of the impact of oil and gas development on the Dene First Nations of the Sahtu (Great Bear Lake) Region of the Canadian Northwest Territories (NWT)  

Microsoft Academic Search

Purpose – Beneath Canada's Northwest Territories lies a potential of 30 trillion cubic feet of natural gas. Will a $16 billion gas-pipeline bring prosperity or gloom? Will this bring employment opportunities for local people or will more qualified people be brought in from southern communities? The purpose of this paper is to give an account of what Dene residents of

Leo Paul Dana; Robert Brent Anderson; Aldene Meis-Mason

2009-01-01

333

Simple Techniques For Assessing Impacts Of Oil And Gas Operations On Public Lands: A Field Evaluation Of A Photoionization Detector (PID) At A Condensate Release Site, Padre Island National Seashore, Texas  

USGS Publications Warehouse

Simple, cost-effective techniques are needed for land managers to assess the environmental impacts of oil and gas production activities on public lands, so that sites may be prioritized for remediation or for further, more formal assessment. Field-portable instruments provide real-time data and allow the field investigator to extend an assessment beyond simply locating and mapping obvious disturbances. Field investigators can examine sites for the presence of hydrocarbons in the subsurface using a soil auger and a photoionization detector (PID). The PID measures volatile organic compounds (VOC) in soil gases. This allows detection of hydrocarbons in the shallow subsurface near areas of obvious oil-stained soils, oil in pits, or dead vegetation. Remnants of a condensate release occur in sandy soils at a production site on the Padre Island National Seashore in south Texas. Dead vegetation had been observed by National Park Service personnel in the release area several years prior to our visit. The site is located several miles south of the Malaquite Beach Campground. In early 2001, we sampled soil gases for VOCs in the area believed to have received the condensate. Our purpose in this investigation was: 1) to establish what sampling techniques might be effective in sandy soils with a shallow water and contrast them with techniques used in an earlier study; and 2) delineate the probable area of condensate release. Our field results show that sealing the auger hole with a clear, rigid plastic tube capped at the top end and sampling the soil gas through a small hole in the cap increases the soil VOC gas signature, compared to sampling soil gases in the bottom of an open hole. This sealed-tube sampling method increases the contrast between the VOC levels within a contaminated area and adjacent background areas. The tube allows the PID air pump to draw soil gas from the volume of soil surrounding the open hole below the tube in a zone less influenced by atmospheric air. In an open hole, the VOC readings seem to be strongly dependent on the degree of diffusion and advection of soil gas VOCs into the open hole from the surrounding soil, a process that may vary with soil and wind conditions. Making measurements with the sealed hole does take some additional time (4-7 minutes after the hole is augered) compared to the open-hole technique (1-2 minutes). We used the rigid-plastic tube technique to survey for soil gas VOCs across the entire site, less than ? acre. Condensate has impacted at least 0.28 acres. The impacted area may extend northwest of the surveyed area.

Otton, James K.; Zielinski, Robert A.

2001-01-01

334

Tracking plasma generated H2O2 from gas into liquid phase and revealing its dominant impact on human skin cells  

NASA Astrophysics Data System (ADS)

The pathway of the biologically active molecule hydrogen peroxide (H2O2) from the plasma generation in the gas phase by an atmospheric pressure argon plasma jet, to its transition into the liquid phase and finally to its inhibiting effect on human skin cells is investigated for different feed gas humidity settings. Gas phase diagnostics like Fourier transformed infrared spectroscopy and laser induced fluorescence spectroscopy on hydroxyl radicals (·OH) are combined with liquid analytics such as chemical assays and electron paramagnetic resonance spectroscopy. Furthermore, the viability of human skin cells is measured by Alamar Blue® assay. By comparing the gas phase results with chemical simulations in the far field, H2O2 generation and destruction processes are clearly identified. The net production rate of H2O2 in the gas phase is almost identical to the H2O2 net production rate in the liquid phase. Moreover, by mimicking the H2O2 generation of the plasma jet with the help of an H2O2 bubbler it is concluded that the solubility of gas phase H2O2 plays a major role in generating hydrogen peroxide in the liquid. Furthermore, it is shown that H2O2 concentration correlates remarkably well with the cell viability. Other species in the liquid like ·OH or superoxide anion radical (O_{2}^{\\cdot -} ) do not vary significantly with feed gas humidity.

Winter, J.; Tresp, H.; Hammer, M. U.; Iseni, S.; Kupsch, S.; Schmidt-Bleker, A.; Wende, K.; Dünnbier, M.; Masur, K.; Weltmann, K.-D.; Reuter, S.

2014-07-01

335

Assessment of non-economic impacts to coastal recreation and tourism from oil and gas development: A review of selected literature and example-methodology. Inventory and evaluation of Washington and Oregon coastal recreation resources  

SciTech Connect

The purpose of the study three-part was to assist Minerals Management Service (MMS) planners in evaluation of the anticipated social impact of proposed oil and gas development on the environment. The Pacific Northwest coastal areas of Washington and Oregon, widely known for their natural beauty, provide a variety of recreational opportunities for both local residents and visitors. In fact, tourism is one of the leading industries in the two states and is an important source of revenue for the economies of many coastal communities. Thus, the Department of Interior, Minerals Management Service (MMS), in anticipation of the proposed Lease Sale 132, funded the research project with the aim of adding to the existing knowledge of Oregon and Washington coastal recreation resources that might be affected by proposed oil and gas development activities.

Kruger, L.E.; Johnson, D.R.; Lee, R.G.

1991-05-01

336

Impact of the Application Technique on Nitrogen Gas Emissions and Nitrogen Budgets in Case of Energy Maize Fertilized with Biogas Residues  

NASA Astrophysics Data System (ADS)

Despite an increasing cultivation of energy maize fertilized with ammonia-rich biogas residues (BR), little is known about the impact of the application technique on gaseous nitrogen (N) losses as well as N budgets, indicative of N use efficiency. To contribute to closing this knowledge gap we conducted a field experiment supplemented by a laboratory incubation study. The field experiment was carried out in Dedelow, located in the Northeastern German Lowlands and characterized by well-drained loamy sand (haplic luvisol). Two treatments with different application technique for BR fertilization - i) trail hoses and ii) injection - were compared to an unfertilized control (0% N). Seventy percent of the applied N-BR was assumed to be plant-available. In 2013, biweekly nitrous oxide (N2O) measurements were conducted during the time period between BR application and maize harvest (18.04.-11.09.2013; 147 days) using non-flow-through non-steady-state chamber measurements. To quantify soil Nmin status, soil samples were taken from 0-30 cm soil depth in the spring (before fertilization) and autumn (after maize harvest). Immediately after BR application, ammonia (NH3) volatilization was measured intensively using the open dynamic chamber Dräger-Tube method. Export of N due to harvest was determined via plant N content (Nharvest). Based on the measured N gas fluxes, N soil and plant parameters, soil N budgets were calculated using a simple difference approach. Values of N output (Nharvest, NN2O_cum and NNH3_cum) are subtracted from N input values (Nfertilizer and Nmin_autumnminus Nmin_spring). In order to correctly interpret N budgets, other N fluxes must be integrated into the budget calculation. Apart from soil-based mobilization and immobilization turnover processes and nitrate leaching, this applies specifically to N2 losses due to denitrification. Therefore, we measured the N2 emissions from laboratory-incubated undisturbed soil cores (250 cm3) by means of the helium incubation approach. With cumulative field emissions of 2.9±0.8 kg N2O-N ha-1 and 3.9±0.4 kg N2O-N ha-1 after trail hose application and injection, respectively, our results showed no clear application effect. NH3-N losses were higher for trail hose application (7.2 kg NH3-N ha-1) compared to injection (5.2 kg NH3-N ha-1). The calculated N budgets showed negative values (accumulative deficit) up to -6 kg N ha-1 and -32 kg N ha-1 for trail hose application and injection, respectively. But differences between treatments were not significant. Overall N budgets were more influenced by plant N uptake (91-96%) than by gaseous N losses (4-9%). However, results from the laboratory incubation indicate that N2 may also be a potentially important pathway of N loss, contributing to 34% of total gaseous N loss, corresponding to 5 kg N2-N ha-1 yr-1.

Andres, Monique; Fränzke, Manuel; Schuster, Carola; Kreuter, Thomas; Augustin, Jürgen

2014-05-01

337

Detection of Mycobacterium tuberculosis in Sputum by Gas Chromatography-Mass Spectrometry of Methyl Mycocerosates Released by Thermochemolysis  

PubMed Central

Tuberculosis requires rapid diagnosis to prevent further transmission and allow prompt administration of treatment. Current methods for diagnosing pulmonary tuberculosis lack sensitivity are expensive or are extremely slow. The identification of lipids using gas chromatography- electron impact mass spectrometry (GC-EI/MS) could provide an alternative solution. We have studied mycocerosic acid components of the phthiocerol dimycocerosate (PDIM) family of lipids using thermochemolysis GC-EI/MS. To facilitate use of the technology in a routine diagnostic laboratory a simple extraction procedure was employed where PDIMs were extracted from sputum using petroleum ether, a solvent of low polarity. We also investigated a method using methanolic tetramethylammonium hydroxide, which facilitates direct transesterification of acidic components to methyl esters in the inlet of the GC-MS system. This eliminates conventional chemical manipulations allowing rapid and convenient analysis of samples. When applied to an initial set of 40 sputum samples, interpretable results were obtained for 35 samples with a sensitivity relative to culture of 94% (95%CI: 69.2,100) and a specificity of 100% (95%CI: 78.1,100). However, blinded testing of a larger set of 395 sputum samples found the assay to have a sensitivity of 61.3% (95%CI: 54.9,67.3) and a specificity of 70.6% (95%CI: 62.3,77.8) when compared to culture. Using the results obtained we developed an improved set of classification criteria, which when applied in a blinded re-analysis increased the sensitivity and specificity of the assay to 64.9% (95%CI: 58.6,70.8) and 76.2% (95%CI: 68.2,82.8) respectively. Highly variable levels of background signal were observed from individual sputum samples that inhibited interpretation of the data. The diagnostic potential of using thermochemolytic GC-EI/MS of PDIM biomarkers for diagnosis of tuberculosis in sputum has been established; however, further refinements in sample processing are required to enhance the sensitivity and robustness of the test. PMID:22403716

O'Sullivan, Denise M.; Nicoara, Simona C.; Mutetwa, Reggie; Mungofa, Stanley; Lee, Oona Y-C.; Minnikin, David E.; Bardwell, Max W.; Corbett, Elizabeth L.; McNerney, Ruth; Morgan, Geraint H.

2012-01-01

338

Outer continental shelf oil and gas activities in the Pacific (Southern California) and their onshore impacts: a summary report, May 1980  

USGS Publications Warehouse

Outer Continental Shelf (OCS) oil and gas exploration and development have been under way in the Pacific (Southern California) Region since 1966. During that time, there have been four Federal lease sales: in 1966, 1968, 1975 (Sale 35), and 1979 (Sale 48). Oil and gas production from three leases has been going on since 1968. It peaked in 1971 and now averages around 31,400 barrels of oil and 15.4 million cubic feet of gas per day. Discoveries on areas leased in the 1968 and 1975 sales have led to plans for eight new platforms to begin production in the early 1980's. Five platforms are in the eastern end of Santa Barbara Channel, one is in the western Channel, and two are in San Pedro Bay, south of Long Beach. Three rigs are doing exploratory drilling in the Region. The most recent estimates by the U.S. Geological Survey of remaining reserves for all identified fields in the Southern California Region are 695 million barrels of oil and 1,575 billion cubic feet of gas (January 1979). The USGS has also made risked estimates of economically recoverable oil and gas resources for all the leased tracts in the Region (March 1980). These risked estimates of economically recoverable resources are 394 billion barrels of oil and 1,295 billion cubic feet of gas. The USGS estimates of undiscovered recoverable resources for the entire Southern California OCS Region (January 1980) are 3,200 million barrels of oil and 3,400 billion cubic feet of gas. Because of the long history of oil and gas production in Southern California from wells onshore and in State waters, there are many existing facilities for the transportation, processing, and refining of oil and gas. Some of the expected new OCS production can be accommodated in these facilities. Four new onshore projects will be required. Two of these are under construction: (1) a 9.6-km (6-mi) onshore oil pipeline (capacity: 60,000 bpd) between Carpinteria (Santa Barbara County) and the existing Mobil-Rincon separation and treatment facility (Ventura County), and (2) a small supply base and dock (upgrade of existing facility) and a 0.4-hectare (1-acre) crude oil distribution facility in Long Beach (Los Angeles County), connected to landfall by a 3-km (1.8-mi) onshore pipeline. The two other facilities are awaiting permit approval: (1) a gas treatment plant at Las Flores Canyon (Santa Barbara County) and (2) a separation and treatment plant at Mandalay Beach (Ventura County) with 4 km (2.5 mi) of onshore pipeline on the same right-of-way from landfall to the plant and from the plant to an existing gas transmission line.

Macpherson, George S.; Bernstein, Janis

1980-01-01

339

Impact of mine closure and access facilities on gas emissions from old mine workings to surface: examples of French iron and coal  

E-print Network

: examples of French iron and coal Lorraine basins C. Lagny, R. Salmon, Z. Pokryszka and S. Lafortune (INERIS of mine shafts located in the iron Lorraine basin, in the Lorraine and in North-East coal basins are quite in mine workings but gas entrance and exit are allowed. Coal shafts are secured and can be equipped

Boyer, Edmond

340

Aroma-impact compounds in dried spice as a quality index using solid phase microextraction with olfactometry and comprehensive two-dimensional gas chromatography.  

PubMed

A systematic experimental procedure is used to identify the aroma-impact compounds, leading to a shelf quality index based on head space solid-phase microextraction. Dried (ground) fennel seeds, having shelf life of 6 months (0.5Y) and 5 years (5Y), were used as a spice model for assessment of comparative aroma quality. Aroma-impact odorants were analysed by GC-olfactometry (GC-O) in parallel with comprehensive two-dimensional GC-flame ionisation detection (GC×GC-FID) using a polar/non-polar phase combination for the GC×GC column set. Tentative identification of aroma-impact odorants involved correlating data from the GC-O/FID system with GC×GC-time-of-flight mass spectrometry analysis by means of retention indices. Major compounds responsible for aroma perception were limonene, 1,8-cineole, terpinen-4-ol, estragole and trans-anethole, and showed an average decrease of 30-50% NIF from 0.5Y to 5Y. Monoterpenes which represent 'freshness', e.g. ?-pinene and ?-myrcene, exhibited identifiable aroma-impact only for the 0.5Y product. Sesquiterpenes and sesquiterpene oxides are suggested as an aging index, being present in increased amounts in 5Y. p-Anisaldehyde odour intensity for both samples remained the same (aroma perception sweet creamy, floral odour and Chinese seasoning powder). PMID:23993622

Maikhunthod, Bussayarat; Marriott, Philip J

2013-12-15

341

Impact of Limitations on Access to Oil and Natural Gas Resources in the Federal Outer Continental Shelf (released in AEO2009)  

EIA Publications

The U.S. offshore is estimated to contain substantial resources of both crude oil and natural gas, but until recently some of the areas of the lower 48 states Outer Continental Shelf (OCS) have been under leasing moratoria. The Presidential ban on offshore drilling in portions of the lower 48 OCS was lifted in July 2008, and the Congressional ban was allowed to expire in September 2008, removing regulatory obstacles to development of the Atlantic and Pacific OCS.

2009-01-01

342

Log-scale permeability estimation from thin sections and its impact on the effective permeability of the formation of Donghae-1 gas field, Block VI1, South Korea  

Microsoft Academic Search

Donghae-1 is an offshore gas reservoir located at the Block VI-1, 60km from Ulsan harbor, South Korea. The reservoir sand interval ranges depths from 2,330m to 2,620m, and is divided into five formations, B1 to B5. There are many thin shale layers in the formations. There are a few lab measurements of permeability and they showed a reasonable porosity-permeability relation

Y. Keehm; D. Hu; T. Mukerji

2007-01-01

343

Impact of the deeper geological basement on soil gas and indoor radon concentrations in areas of Quaternary fluvial sediments (Bohemian Massif, Czech Republic)  

Microsoft Academic Search

The relationship of soil gas radon Rn222 and indoor radon was studied within the Quaternary fluvial sediments of the Czech Republic. The processing of data selection\\u000a from the radon database of the Czech Geological Survey and indoor radon data (database of the National Radiation Protection\\u000a institute) has proved the concentration dependence of radon in Quaternary fluvial sediments on deeper bedrock.

Ivan BarnetPetra; Petra Pacherová

2011-01-01

344

Life-cycle greenhouse gas emissions of shale gas, natural gas, coal, and petroleum.  

PubMed

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. It has been debated whether the fugitive methane emissions during natural gas production and transmission outweigh the lower carbon dioxide emissions during combustion when compared to coal and petroleum. Using the current state of knowledge of methane emissions from shale gas, conventional natural gas, coal, and petroleum, we estimated up-to-date life-cycle greenhouse gas emissions. In addition, we developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings that need to be further addressed. Our base case results show that shale gas life-cycle emissions are 6% lower than conventional natural gas, 23% lower than gasoline, and 33% lower than coal. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty whether shale gas emissions are indeed lower than conventional gas. Moreover, this life-cycle analysis, among other work in this area, provides insight on critical stages that the natural gas industry and government agencies can work together on to reduce the greenhouse gas footprint of natural gas. PMID:22107036

Burnham, Andrew; Han, Jeongwoo; Clark, Corrie E; Wang, Michael; Dunn, Jennifer B; Palou-Rivera, Ignasi

2012-01-17

345

Life-cycle analysis of shale gas and natural gas.  

SciTech Connect

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. Using the current state of knowledge of the recovery, processing, and distribution of shale gas and conventional natural gas, we have estimated up-to-date, life-cycle greenhouse gas emissions. In addition, we have developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps - such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings - that need to be addressed further. Our base case results show that shale gas life-cycle emissions are 6% lower than those of conventional natural gas. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty regarding whether shale gas emissions are indeed lower than conventional gas emissions. This life-cycle analysis provides insight into the critical stages in the natural gas industry where emissions occur and where opportunities exist to reduce the greenhouse gas footprint of natural gas.

Clark, C.E.; Han, J.; Burnham, A.; Dunn, J.B.; Wang, M. (Energy Systems); ( EVS)

2012-01-27

346

Determination of 5alpha-androst-16-en-3alpha-ol in truffle fermentation broth by solid-phase extraction coupled with gas chromatography-flame ionization detector/electron impact mass spectrometry.  

PubMed

A novel method using solid-phase extraction coupled with gas chromatography and flame ionization detector (FID)/electron impact mass spectrometry (EIMS) was developed for the determination of 5alpha-androst-16-en-3alpha-ol (androstenol), a steroidal compound belonging to the group of musk odorous 16-androstenes, in truffle fermentation broth. Comparison studies between FID and EIMS indicated two detectors gave similar quantitative results. The highest androstenol concentration of 123.5 ng/mL was detected in Tuber indicum fermentation broth, while no androstenol was found in Tuber aestivum fermentation broth. For the first time, this work confirmed the existence of androstenol in the truffle fermentation broth, which suggested truffle fermentation is a promising alternative for androstenol production on a large scale. PMID:18585987

Wang, Guan; Li, Yuan-Yuan; Li, Dong-Sheng; Tang, Ya-Jie

2008-07-15

347

Gas Gangrene  

MedlinePLUS

... Issues > Conditions > Skin > Gas Gangrene Health Issues Listen Gas Gangrene Article Body Gangrene describes the death of ... this is the case, the disease is called gas gangrene or clostridial myonecrosis (myo refers to muscle, ...

348

Natural Gas Exports from Iran  

EIA Publications

This assessment of the natural gas sector in Iran, with a focus on Iran’s natural gas exports, was prepared pursuant to section 505 (a) of the Iran Threat Reduction and Syria Human Rights Act of 2012 (Public Law No: 112-158). As requested, it includes: (1) an assessment of exports of natural gas from Iran; (2) an identification of the countries that purchase the most natural gas from Iran; (3) an assessment of alternative supplies of natural gas available to those countries; (4) an assessment of the impact a reduction in exports of natural gas from Iran would have on global natural gas supplies and the price of natural gas, especially in countries identified under number (2); and (5) such other information as the Administrator considers appropriate.

2012-01-01

349

Molasses for ethanol: the economic and environmental impacts of a new pathway for the lifecycle greenhouse gas analysis of sugarcane ethanol  

NASA Astrophysics Data System (ADS)

Many biofuel standards, including California's recently adopted low carbon fuel standard, consider just one feedstock from one supplying country for the production of sugarcane ethanol: fresh mill-pressed cane juice from a Brazilian factory. While cane juice is the dominant feedstock for ethanol in most Brazilian factories, a large number of producers in Indonesia, India, and the Caribbean, and a significant number in Brazil, manufacture most of their ethanol from molasses, a low value co-product of raw sugar. Several producers in these countries have the capacity to export ethanol to California, but the GREET (from: greenhouse gas, regulated emissions and energy use in transportation) model, which is the LCA (lifecycle assessment) model of choice for most biofuel regulators including California, does not currently include this production pathway. We develop a modification to GREET to account for this pathway. We use the upstream and process lifecycle results from the existing GREET model for Brazilian ethanol to derive lifecycle greenhouse gas emissions for ethanol manufactured from any combination of molasses and fresh cane juice. We find that ethanol manufactured with only molasses as a feedstock with all other processes and inputs identical to those of the average Brazilian mill has a lifecycle GHG (greenhouse gas) rating of 15.1 gCO2- eq MJ-1, which is significantly lower than the current California-GREET assigned rating of 26.6 gCO2- eq MJ-1. Our model can be applied at any level of granulation from the individual factory to an industry-wide average. We examine some ways in which current sugarcane producers could inaccurately claim this molasses credit. We discuss methods for addressing this in regulation.

Gopal, Anand R.; Kammen, Daniel M.

2009-10-01

350

The carbon kinetic isotope effects of ozone-alkene reactions in the gas-phase and the impact of ozone reactions on the stable carbon isotope ratios of alkenes in the atmosphere  

NASA Astrophysics Data System (ADS)

The kinetic isotope effects (KIEs) for several ozone-alkene reactions in the gas phase were studied in a 30 L PTFE reaction chamber. The time dependence of the stable carbon isotope ratios and the concentrations were determined using a gas chromatography combustion isotope ratio mass spectrometry (GCC-IRMS) system. The following average KIE values were obtained: 18.9 +/- 2.8 (ethene), 9.5 +/- 2.5 (propene), 8.7 +/- 1 (1-butene), 8.1 +/- 0.4 (E-2-butene), 7.9 +/- 0.4 (1,3-butadiene), 6.7 +/- 0.9 (1-pentene), 7.3 +/- 0.2 (Z-2-pentene), 6.7 +/- 0.7 (cyclopentene), 6.1 +/- 1 (isoprene), 5.0 +/- 0.7 (1-hexene), 5.6 +/- 0.5 (cyclohexene), and 4.3 +/- 0.7 (1-heptene). These data are the first of their kind to be reported in the literature. The ozone-alkene KIE values show a systematic inverse dependence from alkene carbon number. Based on the observed KIEs, the contribution of ozone-alkene reactions to the isotopic fractionation of alkenes in the atmosphere can be estimated. On average this contribution is generally small compared to the impact of reaction with OH radicals. However, when OH-concentrations are very low, e.g. during nighttime and at high latitudes in winter, the contribution of the ozone reaction dominates and under these conditions the ozone-alkene reaction will have a clearly visible impact on the stable carbon isotope ratio of atmospheric alkenes.

Iannone, R.; Anderson, R. S.; Rudolph, J.; Huang, L.; Ernst, D.

2003-07-01

351

Gas gangrene  

MedlinePLUS

Tissue infection - Clostridial; Gangrene - gas; Myonecrosis; Clostridial infection of tissues ... Gas gangrene is most often caused by a bacterium called Clostridium perfringens. It also can be caused ...

352

Impact of biochar application on nitrogen nutrition of rice, greenhouse-gas emissions and soil organic carbon dynamics in two paddy soils of China  

SciTech Connect

Two field microcosm experiments and 15N labeling techniques were used to investigate the first-year effects of biochar addition on rice N nutrition and GHG emissions in an Inceptisol and an Ultisol. Biochar N bioavailability and effect of biochar on fertilizer nitrogen-use efficiency (NUE) were studied by 15N-enriched wheat biochar (7.8803 atom% 15N) and fertilizer urea (5 atom% 15N) (Experiment I). Corn biochar and corn stalks were applied at 12 Mg ha-1 to study their effects on GHG emissions (Experiment II). Biochar had no significant impact on rice production and less than 2% of the biochar N was available to plants in the first season. Biochar addition increased soil C and N contents and decreased urea NUE.. Seasonal cumulative CH4 emissions with biochar were similar to the controls, but significantly lower than the local practice of straw amendment. Soil emissions of N2O with biochar amendment were similar to the control in the acidic Ultisol, but significantly higher in the slightly alkaline Inceptisol. Carbon-balance calculations found no major losses of biochar-C. Low bio-availability of biochar N did not make a significant impact on rice production or N nutrition during the first year.. Replacement of straw amendments with biochar could decrease CH4 emissions and increase SOC stocks.

Xie, Zubin; Xu, Yanping; Liu, Gang; Liu, Qi; Zhu, Jianguo; Tu, Cong; Amonette, James E.; Cadisch, Georg; Yong, Jean W.; Hu, Shuijin

2013-09-01

353

Large-scale depositional characteristics of the Ulleung Basin and its impact on electrical resistivity and Archie-parameters for gas hydrate saturation estimates  

USGS Publications Warehouse

Gas hydrate saturation estimates were obtained from an Archie-analysis of the Logging-While-Drilling (LWD) electrical resistivity logs under consideration of the regional geological framework of sediment deposition in the Ulleung Basin, East Sea, of Korea. Porosity was determined from the LWD bulk density log and core-derived values of grain density. In situ measurements of pore-fluid salinity as well as formation temperature define a background trend for pore-fluid resistivity at each drill site. The LWD data were used to define sets of empirical Archie-constants for different depth-intervals of the logged borehole at all sites drilled during the second Ulleung Basin Gas Hydrate Drilling Expedition (UBGH2). A clustering of data with distinctly different trend-lines is evident in the cross-plot of porosity and formation factor for all sites drilled during UBGH2. The reason for the clustering is related to the difference between hemipelagic sediments (mostly covering the top ?100 mbsf) and mass-transport deposits (MTD) and/or the occurrence of biogenic opal. For sites located in the north-eastern portion of the Ulleung Basin a set of individual Archie-parameters for a shallow depth interval (hemipelagic) and a deeper MTD zone was achieved. The deeper zone shows typically higher resistivities for the same range of porosities seen in the upper zone, reflecting a shift in sediment properties. The presence of large amounts of biogenic opal (up to and often over 50% as defined by XRD data) was especially observed at Sites UBGH2-2_1 and UBGH2-2_2 (as well as UBGH1-9 from a previous drilling expedition in 2007). The boundary between these two zones can also easily be identified in gamma-ray logs, which also show unusually low readings in the opal-rich interval. Only by incorporating different Archie-parameters for the different zones a reasonable estimate of gas hydrate saturation was achieved that also matches results from other techniques such as pore-fluid freshening, velocity-based calculations, and pressure-core degassing experiments. Seismically, individual boundaries between zones were determined using a grid of regional 2D seismic data. Zoning from the Archie-analysis for sites in the south-western portion of the Ulleung Basin was also observed, but at these sites it is linked to individually stacked MTDs only and does not reflect a mineralogical occurrence of biogenic opal or hemipelagic sedimentation. The individual MTD events represent differently compacted material often associated with a strong decrease in porosity (and increase in density), warranting a separate set of empirical Archie-parameters.

Riedel, Michael; Collett, Timothy S.; Kim, H.-S.; Bahk, J.-J.; Kim, J.-H.; Ryu, B.-J.; Kim, G.-Y.

2013-01-01

354

Natural Gas and the Transformation of the U.S. Energy Sector: A Program Studying Multi-sector Opportunities and Impacts  

SciTech Connect

In recognition of the major transitions occurring within the U.S. energy economy, the Joint Institute for Strategic Energy Analysis (JISEA) and Stanford University's Precourt Institute for Energy (PIE) engaged energy system stakeholders from government, industry, academia, and the environmental community in a discussion about the priority issues for a program of rigorous research relating to natural gas. Held December 10-11, 2012 on the Golden, CO campus of the National Renewable Energy Laboratory, the workshop provided invited experts opportunity to describe the state of current knowledge in defined topic areas, and to suggest analytic priorities for that topic area. Following discussion, all stakeholders then contributed potential research questions for each topic, and then determined priorities through an interactive voting process. This record of proceedings focuses on the outcomes of the discussion.

Gossett, S.

2013-01-01

355

Impact of residual carbon on two-dimensional electron gas properties in AlxGa1-xN/GaN heterostructure  

NASA Astrophysics Data System (ADS)

High tuneability of residual carbon doping is developed in a hot-wall metalorganic chemical vapor deposition reactor. Two orders of temperature-tuned carbon concentration, from ˜2 × 1018 cm-3 down to ˜1 × 1016 cm-3, can be effectively controlled in the growth of the GaN buffer layer. Excellent uniformity of two-dimensional electron gas (2DEG) properties in AlxGa1-xN/AlN/GaN heterostructure with very high average carrier density and mobility, 1.1 × 1013 cm-2 and 2035 cm2/V.s, respectively, over 3" semi-insulating SiC substrate is realized with the temperature-tuned carbon doping scheme. Reduction of carbon concentration is evidenced as a key to achieve high 2DEG carrier density and mobility.

Chen-Tai, Jr.; Forsberg, Urban; Janzén, Erik

2013-05-01

356

Environmental Impact of a Tritium Extraction System Small Pipe Break by the Atmospheric Modelling of Elemental Tritium Gas transport with Flexpart  

NASA Astrophysics Data System (ADS)

In the case of a little Tritium-Extraction-System (TES) pipe break (with critical failure of a fuelling line), the tritium source term has not yet been determined in the frame of European Test Blanket Systems, as Design Basis Accident (DBA) but it is expected to be in the order of a few grams. In this critical scenario acute modeling of environmental tritium transport forms (HT and HTO) for the assessment of fusion facilities dosimetric impact appears as of major interest. This paper considers different term releases of tritium-forms to the atmosphere from ITER which has experienced a frequent failure of a fueling line, due the little TES pipe break affecting a Helium-Cooled-Lithium-Lead Test-Blanket-Module. In case of 24.3 g of tritium were released from the broken fuelling-line directly into the gallery found only 0.5 g was released to the environment, assuming a little rupture in the TES piping located in the Port Cell. In this paper we assume a hypothetical daily release of one gram of tritium in HT and HTO forms. The daily failure is taken just in order to evaluate different meteorological scenarios or weather conditions. The FLEXPART working model simulates the tritium forms dispersion and environmental impact out of the complex ITER-tokamak (and its safeguards) of selected environmental patterns both inland and in-sea using ECMWF/FLEXPART model. We explore specific values of this ratio at different levels. We examine the influence of meteorological conditions of the tritium behavior during 48 hours after the release. For this purpose we have FLEXPART version 9.2 numerical weather model which is useful to follow real-time releases of tritium at low levels of the boundary layer to provide an approximation of tritium cloud behavior ranging from 3 to 48 hours.

Castro, Paloma; Ardao, Jose; Velarde, Marta; Xiberta, Jorge; Sedano, Luis

2014-05-01

357

Co-precipitation of radium with barium and strontium sulfate and its impact on the fate of radium during treatment of produced water from unconventional gas extraction.  

PubMed

Radium occurs in flowback and produced waters from hydraulic fracturing for unconventional gas extraction along with high concentrations of barium and strontium and elevated salinity. Radium is often removed from this wastewater by co-precipitation with barium or other alkaline earth metals. The distribution equation for Ra in the precipitate is derived from the equilibrium of the lattice replacement reaction (inclusion) between the Ra(2+) ion and the carrier ions (e.g., Ba(2+) and Sr(2+)) in aqueous and solid phases and is often applied to describe the fate of radium in these systems. Although the theoretical distribution coefficient for Ra-SrSO4 (Kd = 237) is much larger than that for Ra-BaSO4 (Kd = 1.54), previous studies have focused on Ra-BaSO4 equilibrium. This study evaluates the equilibria and kinetics of co-precipitation reactions in Ra-Ba-SO4 and Ra-Sr-SO4 binary systems and the Ra-Ba-Sr-SO4 ternary system under varying ionic strength (IS) conditions that are representative of brines generated during unconventional gas extraction. Results show that radium removal generally follows the theoretical distribution law in binary systems and is enhanced in the Ra-Ba-SO4 system and restrained in the Ra-Sr-SO4 system by high IS. However, the experimental distribution coefficient (Kd') varies widely and cannot be accurately described by the distribution equation, which depends on IS, kinetics of carrier precipitation and does not account for radium removal by adsorption. Radium removal in the ternary system is controlled by the co-precipitation of Ra-Ba-SO4, which is attributed to the rapid BaSO4 nucleation rate and closer ionic radii of Ra(2+) with Ba(2+) than with Sr(2+). Carrier (i.e., barite) recycling during water treatment was shown to be effective in enhancing radium removal even after co-precipitation was completed. Calculations based on experimental results show that Ra levels in the precipitate generated in centralized waste treatment facilities far exceed regulatory limits for disposal in municipal sanitary landfills and require careful monitoring of allowed source term loading (ASTL) for technically enhanced naturally occurring materials (TENORM) in these landfills. Several alternatives for sustainable management of TENORM are discussed. PMID:24670034

Zhang, Tieyuan; Gregory, Kelvin; Hammack, Richard W; Vidic, Radisav D

2014-04-15

358

Outer Continental Shelf oil and gas activities in the Gulf of Alaska and their onshore impacts. Gulf of Alaska summary report update, April 1983  

SciTech Connect

For several years, exploratory drilling has been at a standstill in the subregion. Drilling stopped in the Gulf of Alaska on July 1, 1978, when Exxon, using the Alaskan Star, drilled a dry hole on a Lease Sale 39 tract. In the Cook Inlet drilling continued until June 28, 1980, when ARCO, using the Ocean Bounty, drilled a dry hole on a Lease Sale CI tract. Exploratory drilling has now resumed, however. ARCO, the most active bidder in Lease Sale 55, has submitted an exploratory plan covering seven tracts, and spudded its first well on April 10, 1983. Chevron has two approved exploration plans for Lease Sale 60 tracts and is planning to drill later this year. The existing infrastructures were capable of meeting the demands placed upon them during exploration activities resulting from Lease Sales 39 and CI. Because similar support will be required for the exploration of tracts leased in Lease Sales 55 and 60, the effects on communities providing support are expected to be minimal. If a commercial discovery of oil or gas is made in the Gulf of Alaska subregion, the OCS Information Program will issue a new summary report to aid State and local planners plan for the effects associated with development. Otherwise, this report will be updated aperiodically. The staff of the OCS Information Program is also available to assist agencies if additional information or clarification is desired. The address and phone number of the OCS Information Program are inside the front cover of this report.

Jackson, J.B.

1983-04-01

359

Anaesthesia gas supply: gas cylinders.  

PubMed

Invention of oxygen cylinder was one of the most important developments in the field of medical practice. Oxygen and other gases were compressed and stored at high pressure in seamless containers constructed from hand-forged steel in1880. Materials technology has continued to evolve and now medical gas cylinders are generally made of steel alloys or aluminum. The filling pressure as well as capacity has increased considerably while at the same time the weight of cylinders has reduced. Today oxygen cylinder of equivalent size holds a third more oxygen but weighs about 20 kg less. The cylinders are of varying sizes and are color coded. They are tested at regular intervals by the manufacturer using hydraulic, impact, and tensile tests. The top end of the cylinder is fitted with a valve with a variety of number and markings stamped on it. Common valve types include: Pin index valve, bull nose, hand wheel and integral valve. The type of valve varies with cylinder size. Small cylinders have a pin index valve while large have a bull nose type. Safety features in the cylinder are: Color coding, pin index, pressure relief device, Bodok seal, and label attached etc., Safety rules and guidelines must be followed during storage, installation and use of cylinders to ensure safety of patients, hospital personnel and the environment. PMID:24249883

Srivastava, Uma

2013-09-01

360

Anaesthesia Gas Supply: Gas Cylinders  

PubMed Central

Invention of oxygen cylinder was one of the most important developments in the field of medical practice. Oxygen and other gases were compressed and stored at high pressure in seamless containers constructed from hand-forged steel in1880. Materials technology has continued to evolve and now medical gas cylinders are generally made of steel alloys or aluminum. The filling pressure as well as capacity has increased considerably while at the same time the weight of cylinders has reduced. Today oxygen cylinder of equivalent size holds a third more oxygen but weighs about 20 kg less. The cylinders are of varying sizes and are color coded. They are tested at regular intervals by the manufacturer using hydraulic, impact, and tensile tests. The top end of the cylinder is fitted with a valve with a variety of number and markings stamped on it. Common valve types include: Pin index valve, bull nose, hand wheel and integral valve. The type of valve varies with cylinder size. Small cylinders have a pin index valve while large have a bull nose type. Safety features in the cylinder are: Color coding, pin index, pressure relief device, Bodok seal, and label attached etc., Safety rules and guidelines must be followed during storage, installation and use of cylinders to ensure safety of patients, hospital personnel and the environment. PMID:24249883

Srivastava, Uma

2013-01-01

361

Environmental impact report (draft)  

SciTech Connect

The three projects as proposed by Pacific Gas and Electric Company and the environmental analysis of the projects are discussed. Sections on the natural and social environments of the proposed projects and their surrounding areas consist of descriptions of the setting, discussions of the adverse and beneficial consequences of the project, and potential mitigation measures to reduce the effects of adverse impacts. The Environmental Impact Report includes discussions of unavoidable adverse effects, irreversible changes, long-term and cumulative impacts, growth-inducing effects, and feasible alternatives to the project. (MHR)

Not Available

1980-05-01

362

Log-scale permeability estimation from thin sections and its impact on the effective permeability of the formation of Donghae-1 gas field, Block VI-1, South Korea  

NASA Astrophysics Data System (ADS)

Donghae-1 is an offshore gas reservoir located at the Block VI-1, 60km from Ulsan harbor, South Korea. The reservoir sand interval ranges depths from 2,330m to 2,620m, and is divided into five formations, B1 to B5. There are many thin shale layers in the formations. There are a few lab measurements of permeability and they showed a reasonable porosity-permeability relation for the entire reservoir. However, investigating thin sections revealed that formations can have a different lithology each other, and there are lithological differences even within a formation. This requires more careful and detailed investigation. We first obtained blue-epoxy saturated thin sections from available core samples at every 10cm depth, then estimated porosity and permeability from each thin section by the computational rock physics method, which estimates permeability by lattice-Boltzmann flow simulations on stochastically created 3D pore structures from thin section images. The numerically estimated permeabilites were compared to the lab measurements for quality control purposes. This enabled us to have different porosity-permeability relation in each formation. We even try to have multiple relations within a formation for B4 and B5. The multiple porosity-permeability relations were applied to the entire reservoir intervals using the well-log data and we could obtain well-log scale permeability estimation. This new methodology can give a better estimation for effective permeability for the reservoir and can be applied to the reservoir containing log-scale layers with measurable lithological differences.

Keehm, Y.; Hu, D.; Mukerji, T.

2007-12-01

363

Impact of greenhouse gas metrics on the quantification of agricultural emissions and farm-scale mitigation strategies: a New Zealand case study  

NASA Astrophysics Data System (ADS)

Agriculture emits a range of greenhouse gases. Greenhouse gas metrics allow emissions of different gases to be reported in a common unit called CO2-equivalent. This enables comparisons of the efficiency of different farms and production systems and of alternative mitigation strategies across all gases. The standard metric is the 100 year global warming potential (GWP), but alternative metrics have been proposed and could result in very different CO2-equivalent emissions, particularly for CH4. While significant effort has been made to reduce uncertainties in emissions estimates of individual gases, little effort has been spent on evaluating the implications of alternative metrics on overall agricultural emissions profiles and mitigation strategies. Here we assess, for a selection of New Zealand dairy farms, the effect of two alternative metrics (100 yr GWP and global temperature change potentials, GTP) on farm-scale emissions and apparent efficiency and cost effectiveness of alternative mitigation strategies. We find that alternative metrics significantly change the balance between CH4 and N2O; in some cases, alternative metrics even determine whether a specific management option would reduce or increase net farm-level emissions or emissions intensity. However, the relative ranking of different farms by profitability or emissions intensity, and the ranking of the most cost-effective mitigation options for each farm, are relatively unaffected by the metric. We conclude that alternative metrics would change the perceived significance of individual gases from agriculture and the overall cost to farmers if a price were applied to agricultural emissions, but the economically most effective response strategies are unaffected by the choice of metric.

Reisinger, Andy; Ledgard, Stewart

2013-06-01

364

Situated lifestyles: II. The impacts of urban density, housing type and motorization on the greenhouse gas emissions of the middle-income consumers in Finland  

NASA Astrophysics Data System (ADS)

The relationship between urban form and greenhouse gas (GHG) emissions has been studied extensively during the last two decades. The prevailing paradigm arising from these studies is that a dense or compact urban form would best enable low-carbon living. However, the vast majority of these studies have actually concentrated on transportation and/or housing energy, whereas a growing number of studies argue that the GHG implications of other consumption should be taken into account and the relationships evaluated. With this two-part study of four different area types in Finland we illustrate the importance of including all the consumption activities into the GHG assessment. Furthermore, we add to the discussion the idea that consumption choices, or lifestyles, and the resulting GHGs are not just a product of the values of individuals but actually tied to the form of the surrounding urbanization: that is, lifestyles are situated. In part I (Heinonen et al 2013 Environ. Res. Lett. 8 025003) we looked into this situation in Finland, showing how the residents of the most urbanized areas bring about the highest GHG emissions due to their higher consumption volumes and the economies-of-scale advantages in the less urbanized areas. In part II here, we concentrate only on the middle-income segment and look for differences in the lifestyles when the budget constraints are equal. Here we also add the variables housing type and motorization into the assessment. The same time-use and private expenditure data as in part I and the same GHG assessment method are used here to maintain high transparency and comparability between the two parts. The results of the study imply that larger family sizes and economies-of-scale effects in the less dense areas offset the advantages of more dense living when the emissions are assessed on per capita basis. Also, at equal income levels the carbon footprints vary surprisingly little due to complementary effects of the majority of low-carbon lifestyle choices. Motorization was still found to increase the emissions, but a similar pattern regarding housing type was not found.

Heinonen, Jukka; Jalas, Mikko; Juntunen, Jouni K.; Ala-Mantila, Sanna; Junnila, Seppo

2013-09-01

365

Studies on the impact, detection, and control of microbiology influenced corrosion related to pitting failures in the Russian oil and gas industry. Final CRADA report.  

SciTech Connect

The objectives of the Project are: (1) to design effective anti-corrosion preparations (biocides, inhibitors, penetrants and their combinations) for gas- and oil-exploration industries; (2) to study a possibility of development of environmentally beneficial ('green') biocides and inhibitors of the new generation; (3) to develop chemical and microbiological methods of monitoring of sites at risk of corrosion; and (4) to evaluate potentialities in terms of technology, raw materials and material and technical basis to set up a production of effective anti-corrosion preparations of new generation in Russia. During the four years of the project 228 compounds and formulations were synthesized and studied in respect to their corrosion inhibiting activity. A series of compounds which were according to the Bubble tests more efficient (by a factor of 10-100) than the reference inhibitor SXT-1102, some possessing the similar activity or slightly better activity than new inhibitor ??-1154? (company ONDEO/Nalco). Two synthetic routes for the synthesis of mercaptopyrimidines as perspective corrosion inhibitors were developed. Mercaptopyrimidine derivatives can be obtained in one or two steps from cheap and easily available precursors. The cost for their synthesis is not high and can be further reduced after the optimization of the production processes. A new approach for lignin utilization was proposed. Water-soluble derivative of lignin can by transformed to corrosion protective layer by its electropolymerization on a steel surface. Varying lignosulfonates from different sources, as well as conditions of electrooxidation we proved, that drop in current at high anodic potentials is due to electropolymerization of lignin derivative at steel electrode surface. The electropolymerization potential can be sufficiently decreased by an increase in ionic strength of the growing solution. The lignosulfonate electropolymerization led to the considerable corrosion protection effect of carbon steel. More than three times decrease of corrosion rate on steel surface was observed after lignosulfonate electropolymerization, exceeding protective effect of standard commercially available corrosion inhibitor. Solikamsky lignin could be a promising candidate as a base for the development of the future green corrosion inhibitor. A protective effect of isothiazolones in compositions with other biocides and inhibitors was investigated. Additionally to high biocidal properties, combination of kathon 893 and copper sulfate may also produce a strong anticorrosion effect depending on concentrations of the biocides. Based on its joint biocidal and anticorrosion properties, this combination can be recommended for protection of pipelines against carbon dioxide-induced corrosion. By means of linear polarization resistance test, corrosion properties of biocides of different classes were studied. Isothiazolones can be recommended for treating oil-processing waters in Tatarstan to curb carbon dioxide - induced corrosion. A laboratory research on evaluation of the efficiency of biocides, inhibitors and penetrants by biological and physical-and-chemical methods has been carried out. It was shown that action of corrosion inhibitors and biocides strongly depends on character of their interaction with mineral substances available in waters on oil-exploration sites. It was found that one of approaches to designing environmentally safe ('green') antimicrobial formulations may be the use of synergetic combinations, which allow one to significantly decrease concentrations of biocides. It was shown that the efficacy of biocides and inhibitors depends on physicochemical characteristics of the environment. Anticorrosion and antimicrobial effects of biocides and inhibitors depended in much on the type of medium and aeration regimen. Effects of different biocides, corrosion inhibitors. penetrants and their combinations on the biofilm were investigated. It has been shown that minimal inhibiting concentrations of the reagents for the biofilm are much higher than those for aquatic mic

Ehst, D.

2006-09-30

366

Long-term aerosol and trace gas measurements in Eastern Lapland, Finland: the impact of Kola air pollution to new particle formation and potential CCN  

NASA Astrophysics Data System (ADS)

Sulphur and primary emissions have been decreasing largely all over Europe, resulting in improved air quality and decreased direct radiation forcing by aerosols. The smelter industry in Kola Peninsula is one of largest sources of anthropogenic SO2 within the Arctic domain and since late 1990s the sulphur emissions have been decreasing rapidly (Paatero et al., 2008; Prank et al., 2010). New particle formation (NPF) is tightly linked with the oxidizing product of SO2, namely sulphuric acid (H2SO4), since it is known to be the key component in atmospheric nucleation (Sipilä et al., 2010). Thus, decreasing sulphur pollution may lead to less NPF. However, low values of condensation sink (CS), which is determined by the amount of pre-existing particles, favours NPF. We used 14 years (1998-2011) of aerosol number size distribution and trace gas data from SMEAR I station in Eastern Lapland, Finland, to investigate these relationships between SO2, NPF and CS. The station is a clean background station with occasional sulphur pollution episodes when the air masses arrive over Kola Peninsula. We found that while SO2 decreased by 11.3 % / year, the number of clear NPF event days was also decreasing by 9.9 % / year. At the same time, CS was decreasing also (-8.0 % / year) leading to formation of more particles per single NPF event (J3 increased by 29.7 % / year in 2006-2011) but the low vapour concentrations of H2SO4 (proxy decreased by 6.2 % / year) did not allow them to grow into climatically relevant sizes. Over the time, concentrations of potential CCN (cloud condensing nuclei) were also decreasing with more moderate pace, -4.0 % / year. The events started on average earlier after sunrise when the SO2 concentration during the start of the event was higher and NPF occurred more frequently in air masses which were travelling over Kola. Despite the total decrease in sulphur pollution originating from Kola there is currently no evidence of cleaning of the emissions, rather the decrease is a result of socio-economic changes in the area. It is very likely that in areas with low background aerosol concentrations but close to large sources of anthropogenic sulphur emissions the trends in NPF depend on the overall human activity, general cleaning of the emissions and changes in natural biogenic emissions. This should be taken into account when estimating e.g. the effect of Arctic shipping routes to the future climate. Paatero, J., et al. (2008). Effects of Kola air pollution on the environment in the Western part of the Kola peninsula and Finnish Lapland - Final report. Finnish Meteorological Institute Reports, 6, 1-26. Prank, M., M. et al. (2010). A refinement of the emission data for Kola Peninsula based on inverse dispersion modelling. Atmos. Chem. Phys., 10, 10849-10865. Sipilä, M., et al. (2010). The role of sulfuric acid in atmospheric nucleation. Science, 327, 1243-1246.

Kyrö, Ella-Maria; Väänänen, Riikka; Kerminen, Veli-Matti; Virkkula, Aki; Asmi, Ari; Nieminen, Tuomo; Dal Maso, Miikka; Petäjä, Tuukka; Keronen, Petri; Aalto, Pasi; Riipinen, Ilona; Lehtipalo, Katrianne; Hari, Pertti; Kulmala, Markku

2014-05-01

367

Geomechanical Development of Fractured Reservoirs During Gas Production  

E-print Network

and utilized in a finite element model to coupled gas diffusion and rock mass deformation. The dual permeability method (DPM) is implemented into the Finite Element Model (FEM) to investigate fracture deformation and closure and its impact on gas flow...

Huang, Jian

2013-04-05

368

Economics and Politics of Shale Gas in Europe  

E-print Network

also trigger another wave of price renegotiations, at least for Russian gas contracts. In particular, access to the pipeline network and cost of access are important factors since the economics of shale gas In Europe will be marginal compared... entry). 18 References AMION Consulting (2014). Potential Economic Impacts of Shale Gas in the Ocean Gateway. Available at: http://www.igasplc.com/media/10851/ocean- gateway-shale-gas-impact-study.pdf Barteau, M. and S. Kota (2014). Shale...

Chyong, Chi Kong; Reiner, David M.

2015-01-01

369

Gas vesicles.  

PubMed Central

The gas vesicle is a hollow structure made of protein. It usually has the form of a cylindrical tube closed by conical end caps. Gas vesicles occur in five phyla of the Bacteria and two groups of the Archaea, but they are mostly restricted to planktonic microorganisms, in which they provide buoyancy. By regulating their relative gas vesicle content aquatic microbes are able to perform vertical migrations. In slowly growing organisms such movements are made more efficiently than by swimming with flagella. The gas vesicle is impermeable to liquid water, but it is highly permeable to gases and is normally filled with air. It is a rigid structure of low compressibility, but it collapses flat under a certain critical pressure and buoyancy is then lost. Gas vesicles in different organisms vary in width, from 45 to > 200 nm; in accordance with engineering principles the narrower ones are stronger (have higher critical pressures) than wide ones, but they contain less gas space per wall volume and are therefore less efficient at providing buoyancy. A survey of gas-vacuolate cyanobacteria reveals that there has been natural selection for gas vesicles of the maximum width permitted by the pressure encountered in the natural environment, which is mainly determined by cell turgor pressure and water depth. Gas vesicle width is genetically determined, perhaps through the amino acid sequence of one of the constituent proteins. Up to 14 genes have been implicated in gas vesicle production, but so far the products of only two have been shown to be present in the gas vesicle: GvpA makes the ribs that form the structure, and GvpC binds to the outside of the ribs and stiffens the structure against collapse. The evolution of the gas vesicle is discussed in relation to the homologies of these proteins. Images PMID:8177173

Walsby, A E

1994-01-01

370

Impact of the Manaus urban plume on trace gas mixing ratios near the surface in the Amazon Basin: Implications for the NO-NO2-O3 photostationary state and peroxy radical levels  

NASA Astrophysics Data System (ADS)

We measured the mixing ratios of NO, NO2, O3, and volatile organic carbon as well as the aerosol light-scattering coefficient on a boat platform cruising on rivers downwind of the city of Manaus (Amazonas State, Brazil) in July 2001 (Large-Scale Biosphere-Atmosphere Experiment in Amazonia-Cooperative LBA Airborne Regional Experiment-2001). The dispersion and impact of the Manaus plume was investigated by a combined analysis of ground-based (boat platform) and airborne trace gas and aerosol measurements as well as by meteorological measurements complemented by dispersion calculations (Hybrid Single-Particle Lagrangian Integrated Trajectory model). For the cases with the least anthropogenic influence (including a location in a so far unexplored region ˜150 km west of Manaus on the Rio Manacapuru), the aerosol scattering coefficient, ?s, was below 11 Mm-1, NOx mixing ratios remained below 0.6 ppb, daytime O3 mixing ratios were mostly below 20 ppb and maximal isoprene mixing ratios were about 3 ppb in the afternoon. The photostationary state (PSS) was not established for these cases, as indicated by values of the Leighton ratio, ?, well above unity. Due to the influence of river breeze systems and other thermally driven mesoscale circulations, a change of the synoptic wind direction from east-northeast to south-southeast in the afternoon often caused a substantial increase of ?s and trace gas mixing ratios (about threefold for ?s, fivefold for NOx, and twofold for O3), which was associated with the arrival of the Manaus pollution plume at the boat location. The ratio ? reached unity within its uncertainty range at NOx mixing ratios of about 3 ppb, indicating "steady-state" conditions in cases when radiation variations, dry deposition, emissions, and reactions mostly involving peroxy radicals (XO2) played a minor role. The median midday/afternoon XO2 mixing ratios estimated using the PSS method range from 90 to 120 parts per trillion (ppt) for the remote cases (?s < 11 Mm-1 and NOx < 0.6 ppb), while for the polluted cases our estimates are 15 to 60 ppt. These values are within the range of XO2 estimated by an atmospheric chemistry box model (Chemistry As A Box model Application-Module Efficiently Calculating the Chemistry of the Atmosphere (CAABA/MECCA)-3.0).

Trebs, Ivonne; Mayol-Bracero, Olga L.; Pauliquevis, Theotonio; Kuhn, Uwe; Sander, Rolf; Ganzeveld, Laurens; Meixner, Franz X.; Kesselmeier, Jürgen; Artaxo, Paulo; Andreae, Meinrat O.

2012-03-01

371

Gas separating  

DOEpatents

Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

Gollan, A.

1988-03-29

372

Gas separating  

DOEpatents

Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

Gollan, A.Z.

1990-12-25

373

76 FR 70429 - Notice of Intent To Prepare an Environmental Impact Statement and Notice of Potential Floodplain...  

Federal Register 2010, 2011, 2012, 2013

...proposed project on local sensitive receptors, local environmental conditions, and special- use areas, including impacts to smog and haze, impacts from dusts, and impacts from amine and greenhouse gas emissions; Water resources: potential impacts...

2011-11-14

374

Enhancing impact: visualization of an integrated impact assessment strategy.  

PubMed

The environmental impact assessment process is over 40 years old and has dramatically expanded. Topics, such as social, health and human rights impact are now included. The main body of an impact analysis is generally hundreds of pages long and supported by countless technical appendices. For large, oil/gas, mining and water resources projects both the volume and technical sophistication of the reports has far exceeded the processing ability of host communities. Instead of informing and empowering, the reports are abstruse and overwhelming. Reinvention is required. The development of a visual integrated impact assessment strategy that utilizes remote sensing and spatial analyses is described. PMID:22639133

Krieger, Gary R; Bouchard, Michel A; de Sa, Isabel Marques; Paris, Isabelle; Balge, Zachary; Williams, Dane; Singer, Burton H; Winkler, Mirko S; Utzinger, Jürg

2012-05-01

375

Surface hydrocarbon components of two species of Nasutitermes from Trinidad  

Microsoft Academic Search

Colonies ofNasutitermes costalis (Holmgren) andN. ephratae (Holmgren) were collected from five locations in Trinidad. Cuticular hydrocarbons were characterized by gas chromatography-electron impact mass spectrometry and quantified by capillary gas chromatography. Sixteen major components were identified; all but one component (12, 16-dimethyltriacontane) were common to both species. The methyl-branched hydrocarbons were predominant inN. costalis, while the majority of the hydrocarbon components

Michael I. Haverty; Barbara L. Thorne; Marion Page

1990-01-01

376

Chemical composition, antioxidant and antimicrobial properties of the essential oils of three Salvia species from Turkish flora  

Microsoft Academic Search

Essential oils of three different Salvia species [Salvia aucheri var. aucheri (endemic), Salvia aramiensis and Salvia pilifera (endemic)] were screened for their possible antioxidant and antimicrobial properties as well as their chemical compositions. According to the gas chromatography (GC)\\/EIMS (gas chromatography\\/electron impact mass spectrum) analysis results; 41 (97.2%), 51 (98.5%) and 83 compounds (98.2%) were identified, respectively. While 1,8-cineole (30.5%),

Mustafa Kelen; Bektas Tepe

2008-01-01

377

A Numerical Study of Microscale Flow Behavior in Tight Gas and Shale Gas Reservoir Systems  

Microsoft Academic Search

Various attempts have been made to model flow in shale gas systems. However, there is currently little consensus regarding\\u000a the impact of molecular and Knudsen diffusion on flow behavior over time in such systems. Direct measurement or model-based\\u000a estimation of matrix permeability for these “ultra-tight” reservoirs has proven unreliable. The composition of gas produced\\u000a from tight gas and shale gas

C. M. Freeman; G. J. Moridis; T. A. Blasingame

378

A gas jet impacting a cavity  

NASA Astrophysics Data System (ADS)

A subsonic jet impinging upon a cavity is studied to explain the resultant heating phenomenon. Flow visualization within the cavity shows a large central vortex dominating the flow pattern. Velocity measurements inside the cavity are made using a hot-wire anemometer. Temperature is measured with a copper-constantan thermocouple. The velocity field within the cavity is described by a modified Rankine combined vortex. An uncommon form of the energy equation is used to account for turbulent heating in adverse pressure gradients. A theoretical solution is developed to model the temperature field in the cavity. There is a good agreement between the calculated and measured temperatures. The heating effect is related to Ranque-Hilsch tubes.

Stiffler, A. Kent; Bakhsh, Hazoor

1986-11-01

379

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING  

SciTech Connect

A new project was initiated this quarter to develop gas/liquid membranes for natural gas upgrading. Efforts have concentrated on legal agreements, including alternative field sites. Gas Technology Institute (GTI) is conducting this research program whose objective is to develop gas/liquid membranes for natural gas upgrading to assist DOE in achieving their goal of developing novel methods of upgrading low quality natural gas to meet pipeline specifications. Kvaerner Process Systems (KPS) and W. L. Gore & Associates (GORE) gas/liquid membrane contactors are based on expanded polytetrafluoroethylene (ePTFE) membranes acting as the contacting barrier between the contaminated gas stream and the absorbing liquid. These resilient membranes provide much greater surface area for transfer than other tower internals, with packing densities five to ten times greater, resulting in equipment 50-70% smaller and lower weight for the same treating service. The scope of the research program is to (1) build and install a laboratory- and a field-scale gas/liquid membrane absorber; (2) operate the units with a low quality natural gas feed stream for sufficient time to verify the simulation model of the contactors and to project membrane life in this severe service; and (3) conducted an economic evaluation, based on the data, to quantify the impact of the technology. Chevron, one of the major producers of natural gas, has offered to host the test at a gas treating plant. KPS will use their position as a recognized leader in the construction of commercial amine plants for building the unit along with GORE providing the membranes. GTI will provide operator and data collection support during lab- and field-testing to assure proper analytical procedures are used. Kvaerner and GTI will perform the final economic evaluation. GTI will provide project management and be responsible for reporting and interactions with DOE on this project.

Howard S. Meyer

2002-06-01

380

Impact Tectonics  

NASA Astrophysics Data System (ADS)

This volume is the 8th in a series of impact books resulting from the activities of the scientific program "Response of the Earth System to Impact Processes" (IMPACT), by the European Science Foundation. The book resulted from an international meeting at Mora, Sweden, which was held as part of the IMPACT program. The papers cover various structural geologic, geochemical, and geophysical topics on research of asteroid impact structures on Earth and Mars.

Koeberl, Christian; Henkel, Herbert

381

75 FR 63469 - Environmental Impacts Statements; Notice of Availability  

Federal Register 2010, 2011, 2012, 2013

...nepa/. Weekly receipt of Environmental Impact Statements Filed 10...Sale 193, Analyzing the Environmental Impact of Natural Gas Development...To Evaluate Coastal Storm Damage Reduction, Topsail Island...12, 2010. Cliff Rader, Environmental Protection Specialist,...

2010-10-15

382

Gasotransmitters, poisons, and antimicrobials: it's a gas, gas, gas!  

PubMed Central

We review recent examples of the burgeoning literature on three gases that have major impacts in biology and microbiology. NO, CO and H2S are now co-classified as endogenous gasotransmitters with profound effects on mammalian physiology and, potentially, major implications in therapeutic applications. All are well known to be toxic yet, at tiny concentrations in human and cell biology, play key signalling and regulatory functions. All may also be endogenously generated in microbes. NO and H2S share the property of being biochemically detoxified, yet are beneficial in resisting the bactericidal properties of antibiotics. The mechanism underlying this protection is currently under debate. CO, in contrast, is not readily removed; mounting evidence shows that CO, and especially organic donor compounds that release the gas in biological environments, are themselves effective, novel antimicrobial agents. PMID:23967379

2013-01-01

383

Technology's Impact on Production  

SciTech Connect

As part of a cooperative agreement with the United States Department of Energy (DOE) - entitled Technology's Impact on Production: Developing Environmental Solutions at the State and National Level - the Interstate Oil and Gas Compact Commission (IOGCC) has been tasked with assisting state governments in the effective, efficient, and environmentally sound regulation of the exploration and production of natural gas and crude oil, specifically in relation to orphaned and abandoned wells and wells nearing the end of productive life. Project goals include: (1) Developing (a) a model framework for prioritization and ranking of orphaned or abandoned well sites; (b) a model framework for disbursement of Energy Policy Act of 2005 funding; and (c) a research study regarding the current status of orphaned wells in the nation. (2) Researching the impact of new technologies on environmental protection from a regulatory perspective. Research will identify and document (a) state reactions to changing technology and knowledge; (b) how those reactions support state environmental conservation and public health; and (c) the impact of those reactions on oil and natural gas production. (3) Assessing emergent technology issues associated with wells nearing the end of productive life. Including: (a) location of orphaned and abandoned well sites; (b) well site remediation; (c) plugging materials; (d) plug placement; (e) the current regulatory environment; and (f) the identification of emergent technologies affecting end of life wells. New Energy Technologies - Regulating Change, is the result of research performed for Tasks 2 and 3.

Rachel Amann; Ellis Deweese; Deborah Shipman

2009-06-30

384

Gas Analyzer  

NASA Technical Reports Server (NTRS)

The M200 originated in the 1970's under an Ames Research Center/Stanford University contract to develop a small, lightweight gas analyzer for Viking Landers. Although the unit was not used on the spacecraft, it was further developed by The National Institute for Occupational Safety and Health (NIOSH). Three researchers from the project later formed Microsensor Technology, Inc. (MTI) to commercialize the analyzer. The original version (Micromonitor 500) was introduced in 1982, and the M200 in 1988. The M200, a more advanced version, features dual gas chromatograph which separate a gaseous mixture into components and measure concentrations of each gas. It is useful for monitoring gas leaks, chemical spills, etc. Many analyses are completed in less than 30 seconds, and a wide range of mixtures can be analyzed.

1989-01-01

385

Gas Chromatography  

NSDL National Science Digital Library

This is a website from the US Environmental Protection Agency that explains Gas Chromatography for those interested in environmental analysis. The level of the material assumes some user background in the field.

386

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING  

SciTech Connect

Gas Technology Institute (GTI) is conducting this research program whose objective is to develop gas/liquid membranes for natural gas upgrading to assist DOE in achieving their goal of developing novel methods of upgrading low quality natural gas to meet pipeline specifications. Kvaerner Process Systems (KPS) and W. L. Gore & Associates (GORE) gas/liquid membrane contactors are based on expanded polytetrafluoroethylene (ePTFE) membranes acting as the contacting barrier between the contaminated gas stream and the absorbing liquid. These resilient membranes provide much gr