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1

Determination of thiazolidine-4-carboxylates in urine by chloroformate derivatization and gas chromatography-electron impact mass spectrometry.  

PubMed

The derivatization method of thiazolidine-4-carboxylic acid (TZCA) and methyl-thiazolidine-4-carboxylic acid (Me-TZCA) in urine with alcohol/chloroformate was achieved. TZCA and Me-TZCA were derivatized in one step in urine with ethyl chloroformate in 1 min at room temperature. The derivatives of TZCA and Me-TZCA had very good chromatographic properties and offered very sensitive response for gas chromatography-electron impact ionization-mass spectrometry (GC-EI-MS). On the basis of derivatization, the method for simultaneous determination of TZCA and Me-TZCA in human urine was developed. Deuterated Me-TZCA (Me-TZCA-d(4)) was synthesized as the internal standard (IS) for the analysis of urine samples. TZCA and Me-TZCA were derivatized and extracted from urine at pH 9.5 with toluene, and then the dried extract was dissolved with 100 microl ethyl acetate and injected in GC/MS system. The recoveries of TZCA and Me-TZCA were about 102 and 103%, respectively, at the concentration of 0.05 mg/l. The method detection limits (MDL) were 1.0 and 0.5 microg/l, respectively, for TZCA and Me-TZCA in 1 ml human urine. The coefficients of variation of TZCA and Me-TZCA were less than 6% at the concentrations of 0.05 and 0.2 mg/l, respectively. To assess the formation of TZCA during inhalation with formaldehyde (FA) (about 3.1 and 38.1 ppm FA in air), urine samples from rats were taken during 3 days after initiation of treatment. The mean amount of TZCA determined was 0.07 mg/l in control group and 0.18 mg/l during treatment with 3.1 ppm. The TZCA levels increased up to about 1.01 mg/l during treatment with 38.1 ppm. It is planned to study whether urinary TZCA can be used as an indicator in the biological monitoring of exposure to FA. PMID:17610311

Shin, Ho-Sang; Ahn, Hye-Sil; Lee, Byung-Hoon

2007-09-01

2

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

3

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...

4

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

5

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

PubMed

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 microl chlorobenzene) and disperser solvent (0.50 ml acetone) for the formation of cloudy solution in 5.00 ml aqueous sample containing analytes. After extraction, phase separation was performed by centrifugation and the enriched analytes in sedimented phase were determined by gas chromatography-electron capture detection (GC-ECD). Our simple conditions were conducted at room temperature with no stiring and no salt addition in order to minimize sample preparation steps. Parameters such as the kind and volume of extraction solvent, the kind and volume of disperser solvent, extraction time and salt effect, were studied and optimized. The method exhibited enrichment factors and recoveries ranging from 711 to 813 and 71.1 to 81.3%, respectively, within very short extraction time. The linearity of the method ranged from 0.05 to 100 microgl(-1) for dichlorobenzene isomers (DCB), 0.002-20 microgl(-1) for trichlorobenzene (TCB) and tetrachlorobenzene (TeCB) isomers and from 0.001 to 4 microgl(-1) for pentachlorobenzene (PeCB) and hexachlorobenzene (HCB). The limit of detection was in the low microgl(-1) level, ranging between 0.0005 and 0.05 microgl(-1). The relative standard deviations (R.S.D.s) for the concentration of DCB isomers, 5.00 microgl(-1), TCB and TeCB isomers, 0.500 microgl(-1), PeCB and HCB 0.100 microgl(-1) in water by using the internal standard were in the range of 0.52-2.8% (n=5) and without the internal standard were in the range of 4.6-6.0% (n=5). The relative recoveries of spiked CBs at different levels of chlorobenzene isomers in tap, well and river water samples were 109-121%, 105-113% and 87-120%, respectively. It is concluded that this method can be successfully applied for the determination of CBs in tap, river and well water samples. PMID:19071629

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

2007-04-30

6

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

7

Rapid analysis of organochlorine and pyrethroid pesticides in tea samples by directly suspended droplet microextraction using a gas chromatography-electron capture detector.  

PubMed

A simple and efficient directly suspended droplet microextraction (DSDME) has been developed to extract and pre-concentrate organochlorine and pyrethrin pesticides from tea samples prior to analysis by a gas chromatography-electron capture detector (GC-ECD). The optimal experimental conditions of DSDME were: 100 ?L isooctane exposed for 15 min to 5 mL of the tea aqueous sample stirred at 1100 rpm. For most of the target analytes, the optimal pretreatment of DSDME processes led to no significant interference of tea matrices. The approach was applied to the determination of organochlorine and pyrethroid pesticides in tea samples, with a linearity range of 0.0005-2 ?g/mL. The relative recoveries of all the pesticides ranged between 80.0% and 120.8% with relative standard deviations (RSDs) in the range of 0.8-19.9% (n=5). The limits of detections (LODs) ranged between 0.04 and 1 ?g/L for all the target pesticides. PMID:22440664

Liu, Dan; Min, Shungeng

2012-04-27

8

Gas chromatography-electron ionization-mass spectrometry quantitation of valproic acid and gabapentin, using dried plasma spots, for therapeutic drug monitoring in in-home medical care.  

PubMed

A simple and sensitive gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) method using dried plasma spot testing cards was developed for determination of valproic acid and gabapentin concentrations in human plasma from patients receiving in-home medical care. We have proposed that a simple, easy and dry sampling method is suitable for in-home medical patients for therapeutic drug monitoring. Therefore, in the present study, we used recently developed commercially available easy handling cards: Whatman FTA DMPK-A and Bond Elut DMS. In-home medical care patients can collect plasma using these simple kits. The spots of plasma on the cards were extracted into methanol and then evaporated to dryness. The residues were trimethylsilylated using N-methyl-N-trimethylsilyltrifluoroacetamide. For GC-EI-MS analysis, the calibration curves on both cards were linear from 10 to 200?µg/mL for valproic acid, and from 0.5 to 10?µg/mL for gabapentin. Intra- and interday precisions in plasma were both ?13.0% (coefficient of variation), and the accuracy was between 87.9 and 112% for both cards within the calibration curves. The limits of quantification were 10?µg/mL for valproic acid and 0.5?µg/mL for gabapentin on both cards. We believe that the present method will be useful for in-home medical care. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24889681

Ikeda, Kayo; Ikawa, Kazuro; Yokoshige, Satoko; Yoshikawa, Satoshi; Morikawa, Norifumi

2014-12-01

9

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

10

A study of the suitability of gas chromatography-electron capture detection for the analysis of deoxynivalenol in cereals  

Microsoft Academic Search

A gas chromatographic-electron capture detection (GC-ECD) method for the analysis of deoxynivalenol (DON) in cereals was investigated.\\u000a The sample was extracted with a mixture of acetonitrile-water and purified with a MycoSep #225 column. The silylation was\\u000a performed with Tri-Sil-TBT reagent, followed by dilution with hexane and a washing step with buffer. By using Tri-Sil-TBT\\u000a reagent no double peaks were observed

M Eskola; G Boonzaaijer; WA van Osenbruggen; A Rizzo; G Tijmensen

2000-01-01

11

Rapid analysis of cyclamate in foods and beverages by gas chromatography-electron capture detector (GC-ECD).  

PubMed

A rapid method for determination of sodium cyclamate in foods and beverages was developed. Sodium cyclamate was converted to N,N-dichloridecyclohexylamine by reaction with sodium hypochlorite under acid condition. N,N-dichloridecyclohexylamine was subsequently extracted by n-hexane and determined by gas chromatography. Conditions such as derivatization time, the concentration of sodium hypochlorite and sulphuric acid were optimised. Amino acids, aliphatic amines, and food additives such as preservatives, dyes and sweeteners showed no interference for quantification of cyclamate. The correlation coefficient of calibration curve was 0.9993 in the range of 5.0-250mg/L. The limits of detection (LOD) and limits of quantification (LOQ) were calculated as three or ten times the signal-to-noise ratio (S/N), respectively. The LOD and LOQ for yellow wine and fruit juice were 0.05 and 0.2mg/L, respectively. The LOD and LOQ for cake and preserved fruit were 0.25 and 0.8mg/kg, respectively. The intra-day and inter-day RSD were 0.28% and 1.1% (n=5), respectively. The method was successfully applied for determination of cyclamate in yellow wine, cake, fruit juice and preserved fruit. This method was simple, fast, and sensitive. It was suitable for the determination of cyclamate in foods and beverages for safety and quality control inspections. PMID:23442705

Yu, Shengbing; Zhu, Binghui; Lv, Fen; Li, Shaoxiao; Huang, Weixiong

2012-10-15

12

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

13

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

14

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

PubMed

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

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

2010-07-01

15

Simultaneous determination of bisphenol A, triclosan, and tetrabromobisphenol A in human serum using solid-phase extraction and gas chromatography-electron capture negative-ionization mass spectrometry  

Microsoft Academic Search

This study aimed at optimizing and validating a sensitive method for simultaneous determination of bisphenol A (BPA), triclosan\\u000a (TCS), and tetrabromobisphenol A (TBBPA) in human serum using solid-phase extraction (SPE) and gas chromatography coupled\\u000a to electron-capture negative-ionization mass spectrometry (GC-ECNI\\/MS). Sample preparation involved denaturation of serum\\u000a proteins with formic acid followed by SPE on an Oasis HLB cartridge. Fractionation was

Alin C. Dirtu; Laurence Roosens; Tinne Geens; Adriana Gheorghe; Hugo Neels; Adrian Covaci

2008-01-01

16

Homogeneous liquid–liquid extraction combined with gas chromatography–electron capture detector for the determination of three pesticide residues in soils  

Microsoft Academic Search

In this study, a new method was developed for analyzing malathion, cypermethrin and lambda-cyhalothrin from soil samples by using homogeneous liquid–liquid extraction (HLLE) and gas chromatography with electron capture detector (GC–ECD). Acetone was used as extraction solvent for the extraction of target pesticides from soil samples. When the extraction process was finished, the target analytes in the extraction solvent were

Xuedong Wang; Xinna Zhao; Xiujuan Liu; Yanyan Li; Lingyan Fu; Jia Hu; Changjiang Huang

2008-01-01

17

Measurement of Low Picomolar Levels of Triamcinolone Acetonide in Human Bronchoalveolar Lavage Fluid by Gas Chromatography-Electron-Capture Negative-Ion Mass Spectrometry  

Microsoft Academic Search

The intense inherent electron-capture properties of the C21 acetate derivative of triamcinolone acetonide (TAA) under methane chemical ionization mass spectrometric conditions were exploited for the development of a highly sensitive and selective gas chromatography-mass spectrometric (GC-MS) technique for measurement of levels of TAA in human bronchoalveolar lavage (BAL) fluid. After the addition of 3.0 ng of a heptadeuterated analog of

Walter C. Hubbard; Mark C. Liu; Carol Bickel; Domenick Argenti; Don Heald; Robert P. Schleimer

2001-01-01

18

Determination of 2,4,6-trichloroanisole in wines by headspace solid-phase microextraction and gas chromatography-electron-capture detection.  

PubMed

One of the most important problems in the wine world, today, is cork taint, which often has been chemically identified as 2,4,6-trichloroanisole (TCA). The perception limit of this compound is very low (close to 10 and 40 ng/l for white and red wines, respectively), so, even at such low concentrations, its presence becomes a problem in wine quality. A method for the analysis of TCA in white and red wines has been developed in our laboratory, using headspace solid-phase microextraction and gas chromatography with electron-capture detection. The method, which has been optimized using an experimental design, involves the use of fibres coated with polydimethylsiloxane (PDMS) and allows the analysis of TCA at very low concentrations (under 500 ng/l) with good accuracy (RSD < or = 10%). The limits of quantification of the method are 5 and 8 ng/l for white and red wines, respectively, while the limit of detection is 1 ng/l for both types of wine. PMID:12456090

Riu, M; Mestres, M; Busto, O; Guasch, J

2002-11-15

19

Miniaturized membrane-assisted solvent extraction combined with gas chromatography/electron-capture detection applied to the analysis of volatile organic compounds.  

PubMed

A new module of membrane-assisted solvent extraction (MASE) with miniaturized membrane bags was applied to the determination of seven volatile organic compounds (VOCs): chloroform, 1,1,1-trichloroethane, trichloroethylene, 1,1,2-trichloroethane, tetrachloroethene, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane with boiling points between 61 and 147 degrees C in aqueous samples. Different from the known procedure the new, shortened membrane bags were filled with 100 microl of an organic solvent. The membrane bags were placed in a 20 ml headspace vial and filled with 15 ml of the aqueous sample. The vial was transferred into an autosampler where it was stirred for a definite time at elevated temperature. After the extraction, 1 microl of the organic extract was transferred into the spilt/splitless injector of a GC system equipped with an electron-capture detector. This work included optimization of the membrane device, the determination of the optimized extraction conditions such as stirring rate, extraction time and the impact of salt addition. The validation of the method involved repeatability, recovery and detection limit studies, followed of its application towards real water samples. The repeatability, expressed as the relative standard deviation of the peak areas of six extractions was below 10%. The detection limits (LODs) were between 5 ng/l (tetrachloroethene) and 50 ng/l (chloroform). Calibration was performed in a range from 5 ng/l to 150 microg/l, since the concentration in the aqueous samples was expected quite various in this concentration range. Five river water samples of Bitterfeld, Saxony-Anhalt, Germany were analyzed with miniaturized-MASE and the results were compared with those obtained with Headspace-Analysis. The method can be fully automated and moreover, it allows the simultaneous determination of volatile and semi volatile compounds. PMID:16325836

Schellin, Manuela; Popp, Peter

2006-01-27

20

Model of an impact gas jet  

Microsoft Academic Search

The paper describes the behavior of an impact gas jet during a sharp change of flow direction relative to the stagnation point. Toepler images indicate that Taylor-Hertler type vortices are the structural basis of turbulence in an impact gas jet. A seven-component flow model is proposed, and the implications for heat exchange are considered.

B. P. Zhilkin; N. I. Syromiatnikov

1977-01-01

21

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

22

Greenhouse Gas Emission Impacts of Carsharing in North America  

Microsoft Academic Search

This paper evaluates the greenhouse gas (GHG) emission impacts that result from individuals participating in carsharing organizations within North America. The authors con- ducted an online survey with members of major carsharing orga- nizations and evaluated the change in annual household emissions (e.g., impact) of respondents that joined carsharing. The results show that a majority of households joining carsharing are

Elliot W. Martin; Susan A. Shaheen

2011-01-01

23

Chondrule Formation: Nebular Gas Confinement of Impact Splashes  

NASA Astrophysics Data System (ADS)

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

Dullemond, Cornelis Petrus; Johansen, Anders

2013-07-01

24

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.

25

Production of neutral gas by micrometeoroid impacts  

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

26

Determining Air Quality and Greenhouse Gas Impacts of  

E-print Network

infrastructure will reduce air pollutant emissions from the transportation sector (3-7), the extent to which airDetermining Air Quality and Greenhouse Gas Impacts of Hydrogen Infrastructure and Fuel Cell Vehicles S H A N E S T E P H E N S - R O M E R O Advanced Power and Energy Program, University

Dabdub, Donald

27

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

28

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

29

DSM impact evaluation of a residential gas dryer program  

SciTech Connect

The purpose of the paper is to present evaluation results of a program that is not widely offered by utilities in the energy business. This impact evaluation is for a Residential Gas Dryer Pilot offered by Public Service Company of Colorado (PSCo). PSCo is a combined utility serving both electricity and gas to about 1,000,000 residential customers in the State of Colorado. In September of 1992, PSCo began offering financial incentives to customers to encourage the purchase and installation of natural gas dryers in existing homes and in new residential construction projects. The goal for participation in the pilot was 200 customers living in PSCo`s Western Division territory. The pilot lasted through January 1993. One hundred nineteen customers had participated in the pilot at its conclusion. Participants received applications for mail-in rebates at the point of purchase. The incentive per participant was $100. PSCo recruited eight appliance retailers in the Western Division area to help with the promotion of the pilot. The appliance retailers informed customers of the financial incentives available from PSCo and helped persuade customers to purchase gas dryers rather than electric dryers. PSCo also promoted the pilot through bill inserts, print media, and radio ads. One of the primary objectives of the pilot is to reduce electric use. For PSCo the benefits of reducing electric use are greater than the cost of supplying more gas. The pilot did not increase the energy efficiency of the end-use since the additional gas use represents more energy consumption than is saved in electricity. The benefits of electric capacity and energy savings are addressed first in the paper. Gross program savings and net program savings are presented. The costs of the DSM program are then briefly described and then the cost-effectiveness results are presented form the Total Resource Perspective.

Guinn, D.M.; Chi, Meng

1994-12-31

30

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

31

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

32

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

33

Review of oil and gas exploitation impacts on grizzly bears  

SciTech Connect

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

Schallenberger, A.

1980-01-01

34

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

35

The greenhouse impact of unconventional gas for electricity generation  

Microsoft Academic Search

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,

Nathan Hultman; Dylan Rebois; Michael Scholten; Christopher Ramig

2011-01-01

36

Dispersive liquid-liquid microextraction followed by gas chromatography-electron capture detection for determination of polychlorinated biphenyls in fish.  

PubMed

A new method of dispersive liquid-liquid microextraction (DLLME) combined with GC-electron capture detection (GC-ECD) was proposed for the extraction and determination of four polychlorinated biphenyls (PCBs) congeners in fish samples. Acetone was used as extraction solvent for the extraction of PCBs from fish samples. The target analytes in the acetone solvent were rapidly transferred to chlorobenzene, which was used as extraction solvent in DLLME procedures. Under the optimum conditions, linearity was obtained in the concentration range from 1.25 to 1250 microg/kg for PCB 52, and 0.25 to 250 microg/kg for PCB 101, 138 and 153. Coefficients of correlation (r2) ranged from 0.9993 to 0.9999. The repeatability was tested by spiking fish samples at 10 microg/kg PCBs, and RSD% (n = 8) varied between 2.2 and 8.4%. The LODs were between 0.12 and 0.35 microg/kg. The enrichment factors of PCBs were from 87 to 123. The relative recoveries of the four PCB congeners for the perch, pomfret and yellow-fin tuna at spiking levels of 10, 20 and 50 microg/kg were in the range of 81.20-100.6%, 85.00-102.7% and 87.80-108.4%, respectively. The results demonstrated that DLLME combined with GC-ECD was a simple, rapid, and efficient technique for the extraction and determination of PCBs in fish samples. PMID:19548213

Hu, Jia; Li, Yanyan; Zhang, Wei; Wang, Huili; Huang, Changjiang; Zhang, Minghua; Wang, Xuedong

2009-06-01

37

Construction and validation of a cryogen free gas chromatography–electron-capture detection system for the measurement of ambient halocarbons  

Microsoft Academic Search

A fully automated GC–ECD system was constructed to perform unattended on site measurement of airborne halocarbons. To adequately manage water vapor during analysis a retractable thermoelectric cooling device was built and incorporated into the automated GC–ECD system for retaining water vapor during sample preconcentration. This device allows the trap tubing to engage with the cooling block when trapping, or disengage

Jia-Lin Wang; Cheng-Hsiu Wu

2002-01-01

38

Under consideration for publication in J. Fluid Mech. 1 Liquid-solid impacts with compressible gas  

E-print Network

which goes on to form a bubble. Violent flows and impacts are much studied but the influence of the air isothermal gas layer. A scaling argument for the flow was developed for the cushioning phase, when the smallUnder consideration for publication in J. Fluid Mech. 1 Liquid-solid impacts with compressible gas

Purvis, Richard

39

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

E-print Network

Modeling impacts of carbon sequestration on net greenhouse gas emissions from agricultural soils impacts of carbon sequestration on net greenhouse gas emissions from agricultural soils in China, Global Biogeochem. Cycles, 23, GB1007, doi:10.1029/2008GB003180. 1. Introduction [2] Carbon (C) sequestration has

40

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

41

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. In Pennsylvania, oil and gas wastewater is sometimes treated at brine treatment facilities and discharged to local bioaccumulation in localized areas of shale gas wastewater disposal. INTRODUCTION The safe disposal of large

Jackson, Robert B.

42

A life cycle impact of the natural gas used in the energy sector in Romania  

Microsoft Academic Search

The world's natural gas consumption continues to grow, increasing its market share of total primary energy consumption. Among the major fuels, natural gas is expected to provide the greatest increase in energy consumption in the world energy sector, due to its relatively low environmental impact and high thermodynamic quality. Natural gas plays a significant role in the energy sector because

Cristian Dinca; Patrick Rousseaux; Adrian Badea

2007-01-01

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

Impact of Natural Gas Price Decontrol on Gas Supply, Demand and Prices  

E-print Network

Major analysis completed recently by the gas transmission and distribution industry concludes that available supplies of gas energy will fall into the range of 23-31 trillion cubic feet (Tcf) by the year 2000, as conventional gas production...

Schlesinger, B.

1982-01-01

45

The Impact of Gas Bulk Rotation on the Ly? Line  

NASA Astrophysics Data System (ADS)

We present results of radiative transfer calculations to measure the impact of gas bulk rotation on the morphology of the Ly? emission line in distant galaxies. We model a galaxy as a sphere with an homogeneous mixture of dust and hydrogen at a constant temperature. These spheres undergo solid-body rotation with maximum velocities in the range 0-300 km s–1 and neutral hydrogen optical depths in the range ?H = 105-107. We consider two types of source distributions in the sphere: central and homogeneous. Our main result is that rotation introduces a dependence of the line morphology with viewing angle and rotational velocity. Observations with a line of sight parallel to the rotation axis yield line morphologies similar to the static case. For lines of sight perpendicular to the rotation axis, both the intensity at the line center and the line width increase with rotational velocity. Along the same line of sight, the line becomes single peaked at rotational velocities close to half the line width in the static case. Notably, we find that rotation does not induce any spatial anisotropy in the integrated line flux, the escape fraction or the average number of scatterings. This is because Lyman scattering through a rotating solid-body proceeds identically to the static case. The only difference is the Doppler shift from the different regions in the sphere that move with respect to the observer. This allows us to derive an analytic approximation for the viewing-angle dependence of the emerging spectrum, as a function of rotational velocity.

Garavito-Camargo, Juan N.; Forero-Romero, Jaime E.; Dijkstra, Mark

2014-11-01

46

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

47

Volcanic gas impacts on vegetation at Turrialba Volcano, Costa Rica  

Microsoft Academic Search

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

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

2010-01-01

48

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

49

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

50

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

51

Gas pre-treatment and their impact on liquefaction processes  

SciTech Connect

Natural gas generally requires removal of H{sub 2}S, CO{sub 2}, COS, organic sulfur compounds, mercury and water prior to liquefaction in order to meet product specifications, avoid blockages and to prevent damage to process equipment. The cost of pre-treatment is dependent on the type and concentrations of the contaminants in the natural gas. Most of the operational base load LNG plants process feed gas with only low concentrations of CO{sub 2}, mercury and water as contaminants. This type of gas requires the minimum of treating, often comprising of a CO{sub 2} removal unit, molecular sieves for drying and a carbon bed for mercury removal. The Shell sulfinol process is the most widely applied acid gas removal process, serving some 40% of the installed base load LNG capacity, and has proven to be very reliable and cost effective. If substantial quantities of H{sub 2}S are present in the feed, a sulfur recovery unit is required as well. When mercaptans are also present in gas feed, the Shell Sulfinol process is strongly preferred, Almost the automatic choice for as the acid gas removal step, since it combines total CO{sub 2} and H{sub 2}S removal with mercaptan removal up to 97%. Formulated methyl diethanol amine (MDEA) solvents have a comparable capital cost to Sulfinol, but lack the mercaptan removal capabilities. There is one exception, the Flexsorb formulation (from Exxon) which also contains sulfolane. Later revamp of a gas pre-treatment unit from limited mercaptan handling capability to significant mercaptan handling capability can also elegantly be done using an integrated Sulfinol based concept. Whereas the capital cost for dehydration and mercury removal depend mainly on the natural gas throughput, the relative capital investment for acid gas removal treating in a LNG plant increases significantly with increasing CO{sub 2} content., At 2% mol CO{sub 2} the acid gas unit represents from 6% of the processing equipment cost at 2% mol CO{sub 2} but at 14% mol CO{sub 2} it represents 15% of the processing equipment cost. The capital cost for dehydration and mercury removal depend mainly on the natural gas throughput. New developments such as membrane technologies are starting to be considered as an option for bulk removal of CO{sub 2} but solvent absorption remains the only cost effective treatment process for gas to meet LNG specifications. Further developments may change this in the future.

Klinkenbijl, J.M.; Dillion, M.L.; Heyman, E.C.

1999-07-01

52

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

Microsoft Academic Search

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 of formaldehyde, a hazardous air pollutant

Eduardo P. Olaguer

2012-01-01

53

The Potential Near Source Ozone Impacts of Upstream Oil and Gas Industry Emissions  

Microsoft Academic Search

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 of formaldehyde, a hazardous air pollutant

Eduardo P. Olaguer

2012-01-01

54

Impacts of Land Conversion for Biofuel Cropping on Soil Organic Matter and Greenhouse Gas Emissions  

Microsoft Academic Search

To assess the value of biofuels, the environmental costs of their production must be compared with the benefits of displacing fossil fuel. This article focuses on the environmental impacts of biofuel cropping systems and calculates net greenhouse gas (GHG) emissions using life cycle analysis. The impacts of corn and switchgrass cropping for ethanol production were calculated for three states in

Stephen J. Del Grosso; Stephen M. Ogle; William J. Parton; Paul R. Adler

2008-01-01

55

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

56

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

57

Impact of Natural Gas Infrastructure on Electric Power Systems  

E-print Network

of energy such as pumped-storage units and photovoltaic/battery systems on power system security by reducing--Combined-cycle unit, electricity market, natural gas infrastructure, pipeline contingency, pumped-storage hydro, renew

Fu, Yong

58

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...

59

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

60

Gas PreTreatment and their Impact on Liquefaction Processes  

Microsoft Academic Search

Summary Natural gas generally requires removal of H2S, CO2, COS, organic sulphur compounds, mercury and water prior to liquefaction in order to meet product specifications, avoid blockages and to prevent damage to process equipment. The cost of pre-treatment is dependent on the type and concentrations of the contaminants in the natural gas. Most of the operational base load LNG plants

J. M. Klinkenbijl; M. L. Dillon; E. C. Heyman

61

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

62

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...correct legal land description for the Gas Hills Uranium Project location is as...

2010-11-04

63

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

Federal Register 2010, 2011, 2012, 2013

...related to the management of oil and gas operations at BISO and...environmental impact statement for an oil and gas management plan for BISO...susceptible to adverse impacts from oil and gas development. Authority...Service, Academy Place, P.O. Box 25287, Denver, Colorado...

2011-06-15

64

Unanswered Questions About the Economic Impact of Gas  

E-print Network

State, American Petroleum Institute) · Arkansas (University of Arkansas) · Texas (Perryman Group Equation Volatile · Ignores Economic Costs · Myopic View · Uses Input-Output Analysis JM Barth & Associates ? · Texas labor force has requisite skill set · Texas has support industry network · Gas company

Sibille, Etienne

65

The greenhouse impact of unconventional gas for electricity generation  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

66

ORIGINAL PAPER Impacts of ocean acidification on respiratory gas exchange  

E-print Network

system is changing rapidly due to rising atmospheric CO2, with current levels expected to rise to between calcifying organisms have been extensively studied; however, effects of imminent CO2 levels on teleost acid,000 latm CO2. The results of the current study clearly show that predicted near-future CO2 levels impact

Grosell, Martin

67

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

68

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

Federal Register 2010, 2011, 2012, 2013

...Commission [Docket No. CP13-502-000] Iroquois Gas Transmission System, L.P.; Notice...impacts of two related projects proposed by Iroquois Gas Transmission System, L.P. (Iroquois) and Constitution Pipeline Company,...

2013-07-16

69

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

70

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.

71

Suppression of large-scale structures in a gas-saturated impact jet  

Microsoft Academic Search

The suppression of large-scale vortex formations under gas-saturation conditions is detected on the basis of measurements\\u000a of the pulsation component of the surface friction when an axisymmetric hot jet of a fluid impinges on an obstacle. The conditions\\u000a for the resonant enhancement of coherent structures and the suppression of broad-band turbulence are determined for single-phase\\u000a and gas-saturated impact jets. The

S. V. Alekseenko; D. M. Markovich; V. I. Semenov

1999-01-01

72

Impact of leaf physiology on gas exchange in a Japanese evergreen broad-leaved forest  

Microsoft Academic Search

We used a multi-layer model to analyse the impact of leaf physiology on the diurnal, seasonal, and inter-annual fluctuations in gas exchange in a warm-temperate evergreen broad-leaved forest in Japan. The influences of physiological parameters at the single leaf scale on the canopy scale gas exchange were investigated, including normalised dark respiration rate, Rnleaf25, normalised maximum carboxylation rate, Vcmax25, and

Yoshiko Kosugi; Satoru Takanashi; Naoko Matsuo; Katsunori Tanaka; Hiroki Tanaka

2006-01-01

73

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

74

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

75

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

76

77 FR 42761 - Final Environmental Impact Statement for the Oil and Gas Management Plan at Big South Fork...  

Federal Register 2010, 2011, 2012, 2013

...2310-0046-422] Final Environmental Impact Statement for the Oil and Gas...availability of a Final Environmental Impact Statement (FEIS) for the Oil...visitor use and experience, and human health and safety. DATES...impacting, or threatening to impact park resources beyond the...

2012-07-20

77

Impact of radial migration on stellar and gas radial metallicity distribution  

E-print Network

Radial migration is defined as the change in guiding centre radius of stars and gas caused by gains or losses of angular momentum that result from gravitational interaction with non-axisymmetric structure. This has been shown to have significant impact on the metallicity distribution in galactic discs, and therefore affects the interpretation of Galactic archeology. We use a simulation of a Milky Way-sized galaxy to examine the effect of radial migration on the star and gas radial metallicity distribution. We find that both the star and gas component show significant radial migration. The stellar radial metallicity gradient remains almost unchanged but the radial metallicity distribution of the stars is broadened to produce a greater dispersion at all radii. However, the metallicity dispersion of the gas remains narrow. We find that the main drivers of the gas metallicity distribution evolution are metal enrichment and mixing: more efficient metal enrichment in the inner region maintains a negative slope in t...

Grand, Robert J J; Cropper, Mark

2014-01-01

78

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

79

Inelastic scattering in ocean water and its impact on trace gas retrievals from satellite data  

Microsoft Academic Search

Over clear ocean waters, photons scattered within the water body contribute significantly to the upwelling flux. In addition to elastic scattering, inelastic Vibrational Raman Scattering (VRS) by liquid water is also playing a role and can have a strong impact on the spectral distribution of the outgoing radiance. Under clear-sky conditions, VRS has an influence on trace gas retrievals from

M. Vountas; A. Richter; F. Wittrock; J. P. Burrows

2003-01-01

80

Inelastic scattering in ocean water and its impact on trace gas retrievals from satellite data  

Microsoft Academic Search

Over clear ocean waters, UV\\/Vis. photons scattered within the water body contribute significantly to the upwelling flux. In addition to elastic scattering, inelastic Vibrational Raman Scattering (VRS) by liquid water is also playing a role and can have a strong impact on the spectral distribution of the outgoing radiance. Under clear-sky conditions, VRS has an influence on trace gas retrievals

M. Vountas; T. Dinter; A. Richter; F. Wittrock; J. P. Burrows

2004-01-01

81

Impacts of Climate Change on Life Climate change is upon us, and greenhouse gas emissions  

E-print Network

to promote understanding of climate change and its consequences For further information contact: Sarah GravemImpacts of Climate Change on Life ________________________________________________________________ Climate change is upon us, and greenhouse gas emissions continue to rise: Air temperatures 1.37º F

Schladow, S. Geoffrey

82

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...

83

CARS, GAS, AND POLLUTION POLICIES Distributional and Efficiency Impacts of Gasoline Taxes  

E-print Network

CARS, GAS, AND POLLUTION POLICIES Distributional and Efficiency Impacts of Gasoline Taxes to influence the fleet composition (e.g., the market share of more fuel-efficient cars) as well as the amount), and Amil Petrin (2002), we account for the imperfectly competitive nature of the new-car market. However

Boyer, Edmond

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

Spatial distribution of the gas phase in an axisymmetric submerged impact jet  

Microsoft Academic Search

Experimental data on the spatial distribution of the gas phase in an axisymmetric impact jet are obtained by the particle\\u000a image velocimetry\\/laser-induced fluorescence (PIV\\/LIF) method. It is shown that the distribution of bubbles in the flow is determined by the dynamics of vortex structures.

A. P. Belousov

2009-01-01

86

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...

87

Impact of natural gas pipeline on mineral and energy development in Alaska  

Microsoft Academic Search

The impact of one primary and seven alternative natural gas pipeline routes and their alternatives on Alaska's mining industry is discussed. Four routes begin on Alaska's North Slope and lead to the 48 contiguous States via Canada, while three routes lead to tidewater where it would be liquified for transport to West Coast ports. The geology and the potential for

R. G. Bottge

1975-01-01

88

Impact of natural gas pipeline on mineral and energy development in Alaska. Open file report  

Microsoft Academic Search

The impact of one primary and seven alternative natural gas pipeline routes and their alternatives on Alaska's mining industry is discussed. Four routes begin on Alaska's North Slope and lead to the 48 contiguous States via Canada, while three routes lead to tidewater where it would be liquified for transport to West Coast ports. This report summarizes the geology and

Bottge

1975-01-01

89

Greenhouse Gas Impacts of Ethanol from Iowa Corn: Life Cycle Analysis versus System-wide Accounting  

Microsoft Academic Search

Life cycle analysis (LCA) is the standard approach used to evaluate the greenhouse gas (GHG) benefits of biofuels. However, it is increasingly recognized that LCA results do not account for some impacts including land use changes that have important implications on GHGs. Thus, an alternative accounting system that goes beyond LCA is needed. In this paper, we contribute to the

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

2008-01-01

90

Recent natural gas mergers/alliances and their impact on processing  

SciTech Connect

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

Kovacs, K. [Vector Associates, Houston, TX (United States); Schwenker, C. [Energy Alliances, Houston, TX (United States)

1997-12-31

91

Evaluation of ecological impacts of synthetic natural gas from wood used in current heating and car systems  

Microsoft Academic Search

A promising option to substitute fossil energy carriers by renewables is the production of synthetic natural gas (SNG) from wood, as this results in a flexible energy carrier usable via existing infrastructure in gas boilers or passenger cars. The comprehensive life cycle-based ecological impact of SNG is investigated and compared with standard fuels delivering the same service (natural gas, fuel

Remo Felder; Roberto Dones

2007-01-01

92

The Impact Of Radio-jet Driven Outflows On The Molecular Gas In Powerful Radio-galaxies  

Microsoft Academic Search

Observations of ionized and neutral gas outflows in radio-galaxies (RG) suggest that AGN feedback has a galaxy-scale impact on the host ISM, but it is still unclear how the molecular gas is affected. Thus it is crucial to determine the physical conditions of the molecular gas in powerful RG to understand how radio sources may regulate the star formation in

Pierre Guillard; P. Ogle; B. Emonts; R. Morganti; P. Appleton; C. Tadhunter; T. Oosterloo; A. Evans

2011-01-01

93

78 FR 47408 - Notice of Intent to Prepare an Environmental Impact Statement for Oil and Gas Leasing and...  

Federal Register 2010, 2011, 2012, 2013

...Impact Statement for Oil and Gas Leasing and...Lands and Federal Mineral Estate and Potentially...amendment to evaluate oil and gas leasing and...lands and Federal mineral estate in the Hollister...process to address oil and gas development...lands and Federal mineral estate in the...

2013-08-05

94

Integrated Assessment of Greenhouse Gas Stabilization Concentrations, Emission Pathways, and Impact Threshold Values for Control of Global Warming  

Microsoft Academic Search

To mitigate the dangerous impacts of global warming to the greatest extent possible, various green- house gas stabilization scenarios have been proposed. Integrated studies are proceeding on emission pathways and the costs of achieving climate stabilization, as well as on the impact risks of global warm- ing. This paper summarizes the existing knowledge on temperature rise, mitigation measures and impact

Kiyoshi TAKAHASHI

95

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

96

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

PubMed

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 km(2) across the Ustyurt (total ? 100,000 km(2)), 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

97

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

SciTech Connect

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

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

2004-05-20

98

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

NASA Astrophysics Data System (ADS)

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

Golmshtok, A. Ya.

2014-07-01

99

Socioeconomic impacts of declining outer continental shelf oil and gas activities in the Gulf of Mexico  

SciTech Connect

The Gulf of Mexico (GOM) outer continental shelf oil and gas industry experienced dramatic changes over recent years. These changes impacted socioeconomic conditions in the adjacent coastal communities. The analysis of individual socioeconomic characteristics provides a base of information which illustrates the changed conditions. Select socioeconomic data for each parish and county in the study area for the years 1960, 1970 and 1980 were inventoried, assembled and tabulated.

McKenzie, L.S.; Xander, P.J.; Johnson, M.T.C.; Davis, D.W.; Baldwin, B.

1993-11-01

100

Regional Impacts of Oil and Gas Development on Ozone Formation in the Western United States  

Microsoft Academic Search

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

Marco A. Rodriguez; Michael G. Barna; Tom Moore; Warren White; Krystyna Trzepla-Nabaglo; Paul Wakabayashi; Charles McDade; Ann Dillner; Hege Indresand; William Malm; Gavin McMeeking; Sonia Kreidenweis; Ezra Levin; Christian Carrico; Derek Day; Jeffrey Collett; Taehyoung Lee; Amy Sullivan; Suresh Raja; Marc Pitchford; Richard Poirot; Bret Schichtel; Patricia Brewer; Mark Green; Shobha Kondragunta; Pubu Ciren; Chuanyu Xu; Delbert Eatough; Robert Farber

2009-01-01

101

Legacies from three former manufactured-gas plants: impacts on groundwater quality  

NASA Astrophysics Data System (ADS)

Groundwater contamination due to accidental releases of mono- and polycyclic aromatic compounds (MAHs and PAHs) from decommissioned manufactured-gas plants is an ongoing and litigious problem. The MAHs and PAHs are derived from coal tar, which was a by-product of the gas-manufacturing process. While originally designed to contain coal tar, the manufactured-gas plant structures that remain today have often degraded over time and are not completely leak-proof. Over a period of many years, subsurface water has seeped into and out of the structures, resulting in groundwater contamination. This was particularly true once the tops of the structures were removed. In this study, process-based simulations were conducted to estimate the groundwater-quality impacts of accidental releases of dissolved naphthalene (C10H8) from the sites of three former manufactured-gas plants. The results from one-dimensional, transient, unsaturated, near-surface fluid-flow and solute-transport simulations served as input to three-dimensional saturated subsurface fluid-flow and solute-transport simulations. The simulation results and sensitivity analysis reported here indicate that accidental releases of naphthalene had significant, negative impacts on groundwater quality at each of the three sites.

Abrams, Robert H.; Loague, Keith

2000-12-01

102

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

103

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

104

Life cycle impacts and benefits of a carbon nanotube-enabled chemical gas sensor.  

PubMed

As for any emerging technology, it is critical to assess potential life cycle impacts prior to widespread adoption to prevent future unintended consequences. The subject of this life cycle study is a carbon nanotube-enabled chemical gas sensor, which is a highly complex, low nanomaterial-concentration application with the potential to impart significant human health benefits upon implementation. Thus, the net lifecycle trade-offs are quantified using an impact-benefit ratio (IBR) approach proposed herein, where an IBR < 1 indicates that the downstream benefits outweigh the upstream impacts. The cradle-to-gate assessment results indicate that the midpoint impacts associated with producing CNTs are marginal compared with those associated with the other manufacturing stages. The cumulative upstream impacts are further aggregated to units of disability-adjusted life years (DALYs) using ReCiPe end point analysis method and quantitatively compared with the potential downstream DALY benefits, as lives saved, during the use phase. The approach presented in this study provides a guiding framework and quantitative method intended to encourage the development of nanoenabled products that have the potential to realize a net environmental, health, or societal benefit. PMID:25188898

Gilbertson, Leanne M; Busnaina, Ahmed A; Isaacs, Jacqueline A; Zimmerman, Julie B; Eckelman, Matthew J

2014-10-01

105

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

106

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

107

Impacts of river bed gas on the hydraulic and thermal dynamics of the hyporheic zone  

NASA Astrophysics Data System (ADS)

Despite the presence of gas in river beds being a well known phenomenon, its potential feedbacks on the hydraulic and thermal dynamics of the hyporheic zone has not been widely studied. This paper explores hypotheses that the presence of accumulated gas impacts the hydraulic and thermal dynamics of a river bed due to changes in specific storage, hydraulic conductivity, effective porosity, and thermal diffusivity. The hypotheses are tested using data analysis and modelling for a study site on the urban River Tame, Birmingham, UK. Gas, predominantly attributed to microbial denitrification, was observed in the river bed up to around 14% by volume, and to at least 0.8 m depth below river bed. Numerical modelling indicates that, by altering the relative hydraulic conductivity distribution, the gas in the river bed leads to an increase of groundwater discharge from the river banks (relative to river bed) by a factor of approximately 2 during river low flow periods. The increased compressible storage of the gas phase in the river bed leads to an increase in the simulated volume of river water invading the river bed within the centre of the channel during storm events. The exchange volume can be more than 30% greater in comparison to that for water saturated conditions. Furthermore, the presence of gas also reduces the water-filled porosity, and so the possible depth of such invading flows may also increase markedly, by more than a factor of 2 in the observed case. Observed diurnal temperature variations within the gaseous river bed at 0.1 and 0.5 m depth are, respectively, around 1.5 and 6 times larger than those predicted for saturated sediments. Annual temperature fluctuations are seen to be enhanced by around 4 to 20% compared to literature values for saturated sediments. The presence of gas may thus alter the bulk thermal properties to such a degree that the use of heat tracer techniques becomes subject to a much greater degree of uncertainty. Although the likely magnitude of thermal and hydraulic changes due to the presence of gas for this site have been demonstrated, further research is needed into the origins of the gas and its spatial and temporal variability to enable quantification of the significance of these changes for chemical attenuation and hyporheic zone biology.

Cuthbert, M. O.; Mackay, R.; Durand, V.; Aller, M.-F.; Greswell, R. B.; Rivett, M. O.

2010-11-01

108

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

109

Oligarchic and giant impact growth of terrestrial planets in the presence of gas giant planet migration  

E-print Network

We present the results of N--body simulations which examine the effect that gas giant planet migration has on the formation of terrestrial planets. The models incorporate a 0.5 Jupiter mass planet undergoing type II migration through an inner protoplanet--planetesimal disk, with gas drag included. Each model is initiated with the inner disk being at successively increased levels of maturity, so that it is undergoing either oligarchic or giant impact style growth as the gas giant migrates. In all cases, a large fraction of the disk mass survives the passage of the giant, either by accreting into massive terrestrial planets shepherded inward of the giant, or by being scattered into external orbits. Shepherding is favored in younger disks where there is strong dynamical friction from planetesimals and gas drag is more influential, whereas scattering dominates in more mature disks where dissipation is weaker. In each scenario, sufficient mass is scattered outward to provide for the eventual accretion of a set of terrestrial planets in external orbits, including within the system's habitable zone. An interesting result is the generation of massive, short period, terrestrial planets from compacted material pushed ahead of the giant. These planets are reminiscent of the short period Neptune mass planets discovered recently, suggesting that such `hot Neptunes' could form locally as a by-product of giant planet migration.

Martyn J. Fogg; Richard P. Nelson

2005-07-07

110

Flowing gas in mass spectrometer: method for characterization and impact on ion processing.  

PubMed

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

Zhou, Xiaoyu; Ouyang, Zheng

2014-10-21

111

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

112

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

SciTech Connect

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

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

1983-04-01

113

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

114

Characteristics of impact-generated plasma with different electron temperature and gas temperature  

NASA Astrophysics Data System (ADS)

The characteristics of the plasma with difference between the electron temperature and gas temperature were investigated and the relationship between the plasma ionization degree and the internal energy of a system was obtained. A group of equations included the chemical reaction equilibrium equation, the chemical reaction rate equation and the energy conservation equation were adopted to calculate the electron density, the electron temperature and the atom temperature with a given internal energy. These equations combined with Navier-Stokes (N-S) equations is solved by a smooth particle hydrodynamic (SPH) code. The charges generated in hypervelocity impacts with five different velocities are calculated and verified with the empirical formulas. The influence of a critical velocity for plasma generation is considered in the empirical formula and the parameters are fitted by the numerical results. By comparing with the results in reference, the fitted new empirical formula is verified to be reasonable and useful for a wide range of impact velocity.

Li, Jianqiao; Song, Weidong; Ning, Jianguo; Tang, Huiping

2014-07-01

115

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

Microsoft Academic Search

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\\u000a biomarkers for exposure to phenothrin, tetramethrin, cyfluthrin, cypermethrin, deltamethrin, and permethrin. In this study,\\u000a the pyrethroid metabolites in workers’ urine samples were monitored for the first time with a novel sample pretreatment process\\u000a combining hollow fiber liquid phase microextraction (HF-LPME) and in-syringe

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

116

2-Phosphoglycolate and glycolate-electrophore detection, including detection of 87 zeptomoles of the latter by gas chromatography-electron-capture mass spectrometry  

Microsoft Academic Search

As a first stage towards a goal of studying some aspects of oxidative damage to DNA and its subsequent repair, we set up three techniques for the detection of 2-phosphoglycolate (PG). This compound is released as a metabolite from the DNA in certain cases of this process. We explored three techniques because we wanted to learn which one(s) would be

Poguang Wang; Veeravagu Murugaiah; Bernice Yeung; Paul Vouros; Roger W. Giese

1996-01-01

117

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

SciTech Connect

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

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

1993-11-01

118

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

119

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

120

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

USGS Publications Warehouse

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

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

2013-01-01

121

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.

122

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

123

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

124

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

125

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

126

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

127

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

Microsoft Academic Search

Alternative-fueled vehicle technologies have been promoted and used for reducing petroleum use, urban air pollution, and greenhouse gas emissions. In this paper, greenhouse gas emission impacts of near-term and long-term light-duty alternative-fueled vehicle technologies are evaluated. Near-term technologies, available now, include vehicles fueled with M85 (85% methanol and 15% gasoline by volume), E85 (85% ethanol that is produced from corn

1997-01-01

128

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

129

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

NASA Technical Reports Server (NTRS)

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

Jones, J. A.

1983-01-01

130

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

NASA Astrophysics Data System (ADS)

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

Jones, J. A.

1983-06-01

131

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

132

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

133

Air Impacts of Increased Natural Gas Acquisition, Processing, and Use: A Critical Review  

E-print Network

to rapid and intensive development of many unconventional natural gas plays (e.g., shale gas, tight sand as sandstones (tight-sand gas), shales (shale gas), and coal (coal-bed methane).1 Between 2000 and 2011% and is expected to reach 80% by 2040.1 In particular, annual shale gas production is expected to double from 7

Jackson, Robert B.

134

STORAGE OF HYDROGEN AS GAS HYDRATES AND ITS NEAR-FUTURE IMPACT ON THE OIL, GAS, CHEMICAL AND AUTOMOTIVE INDUSTRY  

Microsoft Academic Search

At the time of the discovery of gas hydrates, they were just a laboratory curiosity. Later on, they turned out to be the cause of serious problems during transportation of oil and gas in pipelines. No surprise that research activities were mainly focused on solving these problems. By now it is known that at the ocean floor and in the

L. J. Rovetto; C. J. Peters

135

The impacts of nitrous oxide gas on sleep quality during alcohol withdrawal  

PubMed Central

Background Poor quality of sleep among alcoholics and persons undergoing alcohol withdrawal has been described as a possible cause of alcohol relapse. It has been suggested earlier that nitrous oxide gas has a significant effect on the signs of alcohol withdrawal syndrome (AWS) and thus might be expected to reduce sleep disturbance during withdrawal. The aim of the present study was to investigate sleep quality during alcohol withdrawal, to evaluate the correlation between sleep quality and the severity of AWS and alcohol craving, and to determine if nitrous oxide treatment does counteract withdrawal's effects on the quality of sleep. Voluntary patients (n = 105) admitted to the A-Clinic detoxification center with AWS were included in the study. The AWS patients were randomly assigned to one of the following 45-minute gas treatments: (1) nitrous oxide/oxygen; (2) normal air/O2; and (3) medical (normal) air. The study was single-blind by design. Sleep quality was assessed after these treatments during the inpatient period; sleep time, sleep efficiency and the fragmentation of sleep were recorded by wrist-worn actigraphs. Severity of AWS was evaluated by the Clinical Institute Withdrawal Assessment of Alcohol Scale (CIWA-Ar) and that of alcohol dependence and craving by the Obsessive Compulsive Drinking Scale [OCDS] and the Severity of Alcohol Dependence Data (SADD) questionnaire. Results The fragmentation index and the time awake while in bed were both much above the reference values for the Finnish population. These values reflect the restless and disturbed night sleep of the subjects. The only statistically significant effects between the treatment groups were found in the correlations of CIWA-Ar (severity of AWS) scores, OCDS-scores (alcohol craving) and coffee consumption, all of which were positively associated with movement time and negatively with total sleep time and sleep efficiency. The sleep quality of patients treated with nitrous oxide gas did not differ from the sleep quality of those treated with normal air. Conclusions The severity of AWS and coffee consumption had the most significant negative impact on sleep quality. According to our results, nitrous oxide gas does not differ from placebo in its effect on sleep quality during alcohol withdrawal. PMID:21470436

2011-01-01

136

The Economic Impact of the Natural Gas Industry and the Marcellus Shale Development in West Virginia in 2009  

E-print Network

. While formed in the Appalachian Basin over 300 million years ago, the Marcellus Shale play has recently The Economic Impact of the Natural Gas Industry and the Marcellus Shale Development in West reservoir being the Marcellus Shale play. The Marcellus Shale play stretches across an area of 95,000 square

Mohaghegh, Shahab

137

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

138

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...

139

Modeling of Future-Year Emissions Control Scenarios for the Lower Fraser Valley: Impacts of Natural Gas and Propane Vehicle Technologies  

Microsoft Academic Search

The MC2-CALGRID photochemical modeling system is used to simulate the impact of two fuel substitution scenarios on ozone levels for a future year in the Lower Fraser Valley of British Columbia, Canada. The relative impacts of selected natural gas and propane vehicle technologies are compared for the year 2005. The chosen natural gas technology imposes large reductions in nonmethane hydrocarbon

M. Hedley; W. Jiang; R. McLaren; D. L. Singleton

1998-01-01

140

Impact of Rotor Surface Velocity, Leakage Models and Real Gas Properties on Rotordynamic Force Predictions of Gas Labyrinth Seals  

E-print Network

Rotordynamic coefficients of a gas labyrinth seal are assumed to be frequency independent. However, this assumption loses its validity as rotor surface velocity approaches Mach 1. The solution procedure of 1CV model by Childs and Scharrer which...

Thorat, Manish R.

2010-07-14

141

Impact of an artificial surfactant release on airsea gas fluxes during Deep Ocean Gas Exchange Experiment II  

E-print Network

; accepted 7 September 2011; published 12 November 2011. [1] During the 2007 UK SOLAS Deep Ocean Gas Exchange physical barrier and through modification of sea surface hydrodynamics and hence turbulent energy transfer

Ho, David

142

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

SciTech Connect

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

Livingston, Olga V.; Cort, Katherine A.

2011-03-03

143

Formation of secondary aerosols: impact of the gas-phase chemical mechanism  

NASA Astrophysics Data System (ADS)

The impact of two recent gas-phase chemical kinetic mechanisms (CB05 and RACM2) on the formation of secondary inorganic and organic aerosols is compared for simulations of PM2.5 over Europe between 15 July and 15 August 2001. The host chemistry transport model is Polair3D of the Polyphemus air-quality platform. Particulate matter is modeled with SIREAM, which is coupled to the thermodynamic model ISORROPIA and to the secondary organic aerosol module MAEC. Model performance is satisfactory with both mechanisms for speciated PM2.5. The monthly-mean difference of the concentration of PM2.5 is less than 1 ?g/m3 (6%) over the entire domain. Secondary chemical components of PM2.5 include sulfate, nitrate, ammonium and organic aerosols, and the chemical composition of PM2.5 is not significantly different between the two mechanisms. Monthly-mean concentrations of inorganic aerosol are higher with RACM2 than with CB05 (+16% for sulfate, +11% for nitrate, and +12% for ammonium), whereas the concentrations of organic aerosols are slightly higher with CB05 than with RACM2 (+26% for anthropogenic SOA and +1% for biogenic SOA). Differences in the inorganic and organic aerosols result primarily from differences in oxidant concentrations (OH, O3 and NO3). Nitrate formation tends to be HNO3-limited over land and differences in the concentrations of nitrate are due to differences in concentration of HNO3. Differences in aerosols formed from aromatics SVOC are due to different aromatics oxidation between CB05 and RACM2. The aromatics oxidation in CB05 leads to more cresol formation, which then leads to more SOA. Differences in the aromatics aerosols would be significantly reduced with the recent CB05-TU mechanism for toluene oxidation. Differences in the biogenic aerosols are due to different oxidant concentrations (monoterpenes) and different particulate organic mass concentrations affecting the gas-particle partitioning of SOA (isoprene).

Kim, Y.; Sartelet, K.; Seigneur, C.

2010-08-01

144

The impact of CO{sub 2} taxation on oil and gas production in Norway  

SciTech Connect

This paper analyses the effect of the CO{sub 2} tax which was imposed on the burning of gas in the Norwegian sector of the North Sea, effective in 1991. The introduction of the tax resulted in a number of technical improvements aimed at the reduction of flaring, and increased energy efficiency of the power generation and total production process. An economic analysis was done to establish the following: (1) How did the tax affect the profitability of the technical measures which were implemented did the tax make it profitable, or would it have been profitable without the tax; (2) can we expect improvements to continue in the coming years; and (3) what will be the impact on the development of new fields, on field abandonment and on measures to improve oil recovery how much more oil will be left in the reservoir because of the tax. The first task was analyzed by an empirical approach, the latter based on models. The reduction in CO{sub 2} discharge during 1990-1993 was in the order of 8%, the main contribution came from reduction in flaring. This rate of improvement is not expected to continue, since most processes have been brought up to {open_quotes}state-of-the-art{close_quotes} by during these initial years. However, continuous energy optimization is still expected to give some improvements The majority of the technical measures taken to reduce the CO{sub 2} discharge proved to be profitable without the tax, and no unprofitable measures were implemented. The effect of earlier abandonment of fields is smaller than expected, advancing the abandonment by a few weeks for a typical North Sea field. The same seems to be the case for development of new fields. The additional reserves needed to compensate for the tax is in the order of 3 - 4% for a medium GOR oil field, above 5% for a larger gas field.

Celius, H.K. [IKU Petroleum Research, Trondheim (Norway); Ingeberg, K. [ECON Center for Economic Analysis, Oslo (Norway)

1996-12-31

145

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

146

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

NASA Astrophysics Data System (ADS)

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

Pacsi, A. P.; Allen, D.

2013-12-01

147

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

PubMed

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

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

2013-10-15

148

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

149

Gas and Particulate Aircraft Emissions Measurements: Impacts on local air quality.  

NASA Astrophysics Data System (ADS)

Air travel and freight shipping by air are becoming increasingly important and are expected to continue to expand. The resulting increases in the local concentrations of pollutants, including particulate matter (PM), volatile organic compounds (VOCs), and nitrogen oxides (NOX), can have negative impacts on regional air quality, human health and can impact climate change. In order to construct valid emission inventories, accurate measurements of aircraft emissions are needed. These measurements must be done both at the engine exit plane (certification) and downwind following the rapid cooling, dilution and initial atmospheric processing of the exhaust plume. We present here results from multiple field experiments which include the Experiment to Characterize Volatile Aerosol and Trace Species Emissions (EXCAVATE) and the four Aircraft Particle Emissions eXperiments (APEX- 1/Atlanta/2/3) which characterized gas and particle emissions from both stationary or in-use aircraft. Emission indices (EIs) for NOx and VOCs and for particle number concentration, refractory PM (black carbon soot) and volatile PM (primarily sulfate and organic) particles are reported. Measurements were made at the engine exit plane and at several downstream locations (10 and 30 meters) for a number of different engine types and engine thrust settings. A significant fraction of organic particle mass is composed of low volatility oil-related compounds and is not combustion related, potentially emitted by vents or heated surfaces within aircraft engines. Advected plumes measurements from in-use aircraft show that the practice of reduced thrust take-offs has a significant effect on total NOx and soot emitted in the vicinity of the airport. The measurements reported here represent a first observation of this effect and new insights have been gained with respect to the chemical processing of gases and particulates important to the urban airshed.

Jayne, J. T.; Onasch, T.; Northway, M.; Canagaratna, M.; Worsnop, D.; Timko, M.; Wood, E.; Miake-Lye, R.; Herndon, S.; Knighton, B.; Whitefield, P.; Hagen, D.; Lobo, P.; Anderson, B.

2007-12-01

150

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

Microsoft Academic Search

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

Alex Lekov; Andy Sturges; Gabrielle Wong-Parodi

2009-01-01

151

Electronic excitation of gas-phase furan molecules by electron impact  

NASA Astrophysics Data System (ADS)

Experiments and ab initio calculations of the differential and integral cross sections for the electronic excitation from the ground state 1A1 to the 3B2 and 3A1 states of gas-phase furan molecules by low-energy electron impact were performed. Experimental differential cross sections were measured at incident electron energies between 5 and 15 eV and for scattering angles from 10? to 130?. The calculated cross sections were obtained using the Schwinger multichannel method implemented with pseudopotentials. The influence of channel-coupling and polarization effects is investigated through the comparison between three different models of scattering calculations, each one considering a distinct channel-coupling scheme. The comparison of experimental and calculated cross sections for electronically inelastic electron scattering by C4H4O molecules is found to be mostly reasonable. The existing discrepancies in this combined theoretical and experimental study help to illustrate difficulties in readily establishing reliable electronic excitation cross sections of polyatomic molecules by low-energy electrons.

da Costa, Romarly F.; Bettega, Márcio H. F.; Lima, Marco A. P.; Lopes, Maria C. A.; Hargreaves, Leigh R.; Serna, Gabriela; Khakoo, Murtadha A.

2012-06-01

152

The impact of gas bulk rotation on the lyman-alpha line  

E-print Network

We present results of radiative transfer calculations to measure the impact of gas bulk rotation on the morphology of the Lyman $\\alpha$ emission line in distant galaxies. We model a galaxy as a sphere with an homogeneous mixture of dust and hydrogen at a constant temperature. These spheres undergo solid-body rotation with maximum velocities in the range $0-300$ \\kms and neutral hydrogen optical depths in the range $\\tau_{\\rm H}=10^{5}-10^{7}$. We consider two types of source distributions in the sphere: central and homogeneous. Our main result is that rotation introduces a dependence of the line morphology with viewing angle and rotational velocity. Observations with a line of sight parallel to the rotation axis yield line morphologies similar to the static case. For lines of sight perpendicular to the rotation axis both the intensity at the line center and the line width increase with rotational velocity. Along the same line of sight, the line becomes single peaked at rotational velocities close to half the...

Garavito-Camargo, Juan N; Dijkstra, Mark

2014-01-01

153

Municipal solid waste management scenarios for Attica and their greenhouse gas emission impact.  

PubMed

Disposal of municipal solid waste in sanitary landfills is still the main waste management method in the Attica region, as in most regions of Greece. Nevertheless, diversion from landfilling is being promoted by regional plans, in which the perspectives of new waste treatment technologies are being evaluated. The present study aimed to assess the greenhouse gas (GHG) emissions impact of different municipal solid waste treatment technologies currently under assessment in the new regional plan for Attica. These technologies are mechanical-biological treatment, mass-burn incineration and mechanical treatment and have been assessed in the context of different scenarios. The present study utilized existing methodologies and emission factors for the quantification of GHG emissions from the waste management process and found that all technologies under assessment could provide GHG emission savings. However, the performance and ranking of these technologies is strongly dependent on the existence of end markets for the waste-derived fuels produced by the mechanical-biological treatment processes. In the absence of these markets the disposal of these fuels would be necessary and thus significant GHG savings would be lost. PMID:19837710

Papageorgiou, Asterios; Karagiannidis, Avraam; Barton, John R; Kalogirou, Efstratios

2009-11-01

154

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

155

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

156

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

157

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

158

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

SciTech Connect

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

Wang, M.Q.

1997-05-20

159

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

E-print Network

Turbine Exhaust Gas (TEG) contains high levels of oxygen, typically 15 vol. percent, due to gas turbine blade material temperature limits. As such it can be used as an oxidant for combustion in cracking furnaces and reformers. Its high temperature...

Platvoet, E.

2011-01-01

160

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

161

78 FR 23554 - Sierrita Gas Pipeline LLC; Supplemental Notice of Intent To Prepare an Environmental Impact...  

Federal Register 2010, 2011, 2012, 2013

...No. CP13-73-000] Sierrita Gas Pipeline LLC; Supplemental Notice of Intent...operation of facilities by Sierrita Gas Pipeline LLC (Sierrita) in Pima County...of 36-inch-diameter natural gas pipeline and construction of two meter...

2013-04-19

162

Analysis of tert-butyldimethylsilyl derivatives in heavy gas oil from Brazilian naphthenic acids by gas chromatography coupled to mass spectrometry with electron impact ionization.  

PubMed

Naphthenic acids, C(n)H(2n+Z)O(2), are a complex mixture of alkyl-substituted acyclic and cycle-aliphatic carboxylic acids. The content of naphthenic acids and their derivatives in crude oils is very small, which hinders their extraction from matrixes of wide and varied composition. In this work, liquid-liquid extraction, followed by solid phase extraction with an ion exchange resin (Amberlyst A-27) and ultrasound desorption were used to isolate the acid fraction from heavy gas oil of Marlim petroleum (Campos, Rio de Janeiro, Brazil). The analysis was accomplished through gas chromatography coupled to mass spectrometry with electron impact ionization, after derivatization with N-methyl-N-(tert-butyldimethylsilyl)trifluoracetamide (MTBDMSTFA). The results indicate the presence of carboxylic acids belonging to families of alicyclic and naphthenic compounds which contain up to four rings in the molecule. PMID:16439253

Vaz de Campos, Maria Cecília; Oliveira, Eniz Conceição; Filho, Pedro José Sanches; Piatnicki, Clarisse Maria Sartori; Caramão, Elina Bastos

2006-02-10

163

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

164

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

165

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

166

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

SciTech Connect

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

Wiser, Ryan; Bolinger, Mark

2004-09-20

167

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

168

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

SciTech Connect

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

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

2011-07-01

169

IMPACTS OF SEASONALITY ON HYDROGEN PRODUCTION USING NATURAL GAS PRESSURE LETDOWN STATIONS  

Microsoft Academic Search

One of the difficulties associated with the development of a hydrogen economy is the creation of a supply infrastructure. A means for distributed hydrogen generation through a process using the exergy in high pressure natural gas streams has been proposed. The system recovers energy via expansion of natural gas through a turbo-expander at existing pressure reduction systems. Generated electric power

Jesse Maddaloni; Andrew Rowe; Rick Bailey; Duncan McDonald

170

Impact of thermophysical properties research on acid gas injection process design  

SciTech Connect

Stricter regulations and increased environmental concerns are making the previously common practice of flaring acid gas less attractive. Producers are being forced to find alternative methods to deal with this unwanted by-product. Acid gas injection has quickly become the method of choice for disposal, especially for small producers. Presented in this paper is a brief overview of the acid gas injection process. Included in this discussion is a description of what physical property and phase equilibria data are required and why. In addition, some new experimental data for the water content and density of sour gas mixtures are presented. These data are useful for checking the validity of the correlations used in the design of an acid gas injection scheme. In addition, such data are useful for optimizing the interaction parameters in the thermodynamic models employed to calculate such properties.

Ng, H.J.; Carroll, J.J.; Maddocks, J.

1999-07-01

171

Impacts of the tectonic stress field on natural gas migration and accumulation: A case study of the Kuqa Depression in the Tarim Basin, China  

Microsoft Academic Search

Stress, fluid and temperature are three of the major factors that impact natural gas migration and accumulation. In order to study the influences of tectonic stress field on natural gas migration and accumulation in low-permeability rocks, we take the Kuqa Depression as an example and analyze the evolution of the structure and tectonic stress field at first. Then we study

Lianbo Zeng; Hongjun Wang; Lei Gong; Benming Liu

2010-01-01

172

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

PubMed

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

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

2010-12-01

173

Impacts from Climate Change and Adaptation Responses on Energy Economy and Greenhouse Gas Emissions in the Toronto-Niagara Region, Canada  

Microsoft Academic Search

Climate change may impact the energy sector directly and indirectly. The objective of this study is to develop a systematic approach for assessing impacts of climate change and adaptation response as well as the growing population on energy economy and greenhouse gas emissions. Such an approach was based on regional energy systems characterization, climate change scenario analysis, vulnerability assessment, energy

Q. G. Lin; G. H. Huang; B. Bass

2011-01-01

174

Impact of electric power generation on green house gas emissions in Europe: Russia, Greece, Italy and views of the EU power plant supply industry – A critical analysis  

Microsoft Academic Search

This paper analyses the impact of electric power generation on greenhouse gas emissions in Europe (including the Asian part of Russia) with reference to Russia, Greece, Italy, and views of the EU power plant supply industry in respect of the Kyoto protocol. The outlook of power industry development in Russia in the 21st century is first considered and its impact

T. J. Hammons

2006-01-01

175

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

SciTech Connect

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

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

1994-02-10

176

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.

177

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

Federal Register 2010, 2011, 2012, 2013

...natural gas pipeline system in Wyoming, Utah, and Nevada, to...receipt points in southwestern Wyoming, to existing delivery connections...compression: The Coyote Creek Compressor Station located in Uinta County, Wyoming; the Elberta...

2010-08-02

178

The Impact of Biofuel and Greenhouse Gas Policies on Land Management, Agricultural Production, and Environmental Quality  

E-print Network

This dissertation explores the combined effects of biofuel mandates and terrestrial greenhouse gas GHG mitigation incentives on land use, management intensity, commodity markets, welfare, and the full costs of GHG abatement through conceptual...

Baker, Justin Scott

2012-10-19

179

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

180

Electricity price impacts of alternative Greenhouse gas emission cap-and-trade programs  

SciTech Connect

Limits on greenhouse gas emissions would raise the prices of the goods and services that require such emissions for their production, including electricity. Looking at a variety of emission limit cases and scenarios for selling or allocating allowances to load-serving entities, the authors estimate how the burden of greenhouse gas limits are likely to be distributed among electricity consumers in different states. (author)

Edelston, Bruce; Armstrong, Dave; Kirsch, Laurence D.; Morey, Mathew J.

2009-07-15

181

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

182

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

183

Impact of chlorine dioxide gas sterilization on nosocomial organism viability in a hospital room.  

PubMed

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

2013-06-01

184

Impact of Exhaust Gas Recirculation on the Performances of Diesel Engine  

E-print Network

“Worldwide emission regulation has been tightening year after year. Numbers of researchers are trying to work out combinations of key technologies to meet the forth-coming emission norms. Exhaust gas recirculation (EGR) for diesel engine to reduce oxides of nitrogen is chosen for present work. The emphasis is given on oxides of nitrogen (NOx). Experiments were carried out on computerized single cylinder four- stroke diesel engine with eddy current dynamometer (10 BHP 7.4 KW).” “Exhaust gas re-circulation set-up is developed. It consists of EGR cooler; air filters box, rota-meter, exhaust control valve, pressure gauge and temperature indicator etc. Engine set-up was modified and coupled with EGR setup. Exhaust gas recirculation system was tested with different EGR

P. V. Walke; Dr. N. V. Deshp; R. G. Bodkhe

185

Estimating the impact of residential gas cooling equipment on electric utility summer peak in northern California  

SciTech Connect

Residential gas-fired cooling equipment helps electric utilities trim a portion of the summer peak load curve. This paper details a methodology for developing initial estimates of such peak reduction and the consequent savings in plant costs by taking into account a set of key variables. The key variables include the weather patterns over the service territory, the size and distribution of building stock for the residential sector, the availability of gas distribution lines, the market penetration of gas cooling equipment, as a fraction of the maximum possible penetration, and the historical plant cost for generating power. The application of the methodology is illustrated in detail by using a Northern California utility service territory as a case study.

Kumar, B. [Energetics, Inc., Columbia, MD (United States); Nowakowski, G.A. [Gas Research Inst., Chicago, IL (United States)

1995-12-31

186

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

187

Estimation of measurement uncertainty of polychlorinated biphenyls, polycyclic aromatic hydrocarbons and organochlorine pesticides in the atmosphere using gas chromatography-mass spectrometry and gas chromatography-electron capture detector.  

PubMed

Estimation of uncertainty of measurement is a crucial issue to achieve accurate measurement results. When the target has adverse environmental and health effects, accuracy of the results become more important. POPs are the pollutants that have toxic effects and unfortunately, there is a lack of information about uncertainty of the method for determining POPs in air samples. In this work, uncertainty calculations were carried out for PCBs, OCPs, and PAHs in air samples analyzed by using GC-MS and GC-ECD. The main dominant sources for combined uncertainty were calibration curve, recovery and repeatability. The relative uncertainties were found to be in the range of 23-52% for PCBs, 24-59% for OCPs and 23-90% for PAHs. PMID:24369999

Aslan-Sungur, Güler; Gaga, Eftade O; Yenisoy-Karaka?, Serpil

2014-01-17

188

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

PubMed

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

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

2014-11-01

189

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

PubMed

Growing concern over emissions from increased airport operations has resulted in a need to assess the impact of aviation related activities on local air quality in and around airports, and to develop strategies to mitigate these effects. One such strategy being investigated is the use of alternative fuels in aircraft engines and auxiliary power units (APUs) as a means to diversify fuel supplies and reduce emissions. This paper summarizes the results of a study to characterize the emissions of an APU, a small gas turbine engine, burning conventional Jet A-1, a fully synthetic jet fuel, and other alternative fuels with varying compositions. Gas phase emissions were measured at the engine exit plane while PM emissions were recorded at the exit plane as well as 10 m downstream of the engine. Five percent reduction in NO(x) emissions and 5-10% reduction in CO emissions were observed for the alternative fuels. Significant reductions in PM emissions at the engine exit plane were achieved with the alternative fuels. However, as the exhaust plume expanded and cooled, organic species were found to condense on the PM. This increase in organic PM elevated the PM mass but had little impact on PM number. PMID:22913288

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

2012-10-01

190

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

191

IMPACTS AND RECOVERY IN A COLDWATER STREAM FOLLOWING A NATURAL GAS PIPELINE CROSSING INSTALLATION  

Microsoft Academic Search

Findlay Creek is a small, coldwater stream which was crossed by a natural gas pipeline using conventional open- cut techniques in late August 1992. Pipeline crossing activities included the removal of a beaver dam which was located along the proposed alignment, the installation of a temporary road crossing, and the actual pipeline installation. A monitoring study was initiated to examine

Paul G. Anderson; Christian G. J. Fraikin; Trevor J. Chandler

192

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

SciTech Connect

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

Moses, C.A.; Bernstein, H. [Southwest Research Inst., San Antonio, TX (United States)] [Southwest Research Inst., San Antonio, TX (United States)

1994-01-01

193

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

194

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

ERIC Educational Resources Information Center

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

Copp, James H.

195

Minimizing anchoring impacts during construction of offshore oil and gas facilities  

Microsoft Academic Search

Reviewing the development proposed for the Point Arguello Field offshore California, one of the largest domestic oil fields discovered since Prudhoe Bay, has been a challenging experience for Minerals Management Service scientists. Due to the many unusual environmental conditions in this area, special precautions had to be taken to minimize environmental impacts and maximize operational safety. This paper describes the

Mary Elaine Dunaway; Phillip Schroeder

1988-01-01

196

JEDI II: Jobs and Economic Development Impacts from Coal, Natural Gas, and Wind Power (Poster)  

SciTech Connect

Using economic multipliers, JEDI II measures the potential employment (job and earnings) and economic development impacts (output) from new power plants by calculating the dollar flow from construction and annual operations. In its default form, JEDI II conducts state-specific analyses. County or regional analyses require additional multipliers.

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

2006-01-01

197

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

E-print Network

2003). Incidentally, each of these basins underlies current habitat for greater sage-grouse (Centrocercus urophasianus) or Gunnison sage-grouse (C. minimus; Schroeder et al. 2004). Rigorous research activities on prairie grouse, based on 12 papers that report empirical evidence about impacts on greater sage-grouse

Beck, Jeffrey L.

198

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

Microsoft Academic Search

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

C. E. Kirschner; A. Grantz

1990-01-01

199

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

200

The impact of ten years at -20°C on gas exchange in five lichen species  

Microsoft Academic Search

Rates of net CO2 exchange in five sympatric species of Umbilicaria were measured after 10 years at-20°C. During that time, the lichens had been at either a high (saturated) or a low (air-dry) water content. The results showed an immediate, return to normal rates of gas exchange for air-dried then frozen U.vellea. Rates returned to normal for air-dried U. deusta

D. W. Larson

1989-01-01

201

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

202

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

PubMed

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. PMID:20888746

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

2011-05-01

203

The impact of thermal gas in AGN jets on the low-frequency emission  

E-print Network

We study the effect of non-relativistic, thermal matter in the jets of active galaxies (AGN) on the low-frequency non-thermal emission and the variability thereof. In matter-dominated jets, sizable quantities of gas should exist, in particular in the compression zones near the collision fronts that are an implicit ingredient of Fermi-type particle acceleration scenarios. Non-relativistic thermal gas in AGN jets noticably contributes to the optical depth at radio to infrared frequencies, and much less to the emission, with an efficiency that is strongly temperature-dependent. The observable flux of low-frequency emission is thus modulated by the temperature evolution of the thermal gas, and it can therefore display very complicated variability. For a particular particle energisation scenario we calculate the temperature evolution of the thermal plasma as well as the radiation transport of low-frequency emission, and thus derive simulated light curves at different frequencies and their typical correlation properties.

M. Siewert; M. Pohl; R. Schlickeiser

2004-09-03

204

Evaluating 2012 Ozone Impacts of Natural Gas Development in the Haynesville Shale with an Updated Emission Inventory  

NASA Astrophysics Data System (ADS)

The Haynesville Shale, located approximately 10,000-13,000 feet beneath Northeast Texas and Northwest Louisiana contains very large recoverable reserves of natural gas. Development of the Haynesville began in 2008, and since then, more than 3,000 wells have been drilled. The development of natural gas resources in the Haynesville is economically important, but also generates emissions of ozone precursors in a region with several ozone monitors that are close to or exceeding the 2008 National Ambient Air Quality Standard. During 2009, we developed an emission inventory of ozone precursors for projected future Haynesville Shale development from 2009 through 2020. Photochemical modeling with the 2012 emission inventory showed significant ozone impacts within Northeast Texas and Northwest Louisiana as a result of Haynesville emissions, with projected 8-hour ozone design value increases up to 5 ppb at area monitors. The original emission inventory was assembled during spring 2009, early in the development of the Haynesville when available data were limited. Since then, development in the Haynesville has continued, and additional data are now available and were used to refine the development projections and emission inventory through the year 2020. The updated 2012 emission inventory is now based on actual data rather than projections made in 2009. The number of drilling rigs operating in 2012 was lower than projected, but the well count was higher due intensive drilling activity in 2010-2011 that exceeded projections. The updated emission inventory draws on more Haynesville-specific data than the previous inventory. Energy producers currently active in the Haynesville were surveyed and provided information that included well drilling times, equipment used for well construction, production equipment present at typical Haynesville wells, and produced gas composition analyses. Producers provided information on the amount of truck traffic associated with transport of materials, equipment, and personnel to and from wells and the types and activity of non-road equipment operating at well sites. Well production data for 2009 through 2012 from Texas and Louisiana state regulatory agencies was used to update the well decline curve used to project formation-wide gas production. The updated emission inventory was used to quantify 2012 ozone impacts from the Haynesville with the CAMx photochemical grid model. The ozone contribution from truck traffic was determined. We evaluated the effect of the Haynesville on ozone design values in Northeast Texas and Northwest Louisiana as well as on regional ozone. The model projections for ozone were compared to recent trends in observed ozone.

Kemball-Cook, S. R.; Bar-Ilan, A.; Yarwood, G.

2013-12-01

205

A comparison of particle impact in gas-solid and liquid-solid erosion  

Microsoft Academic Search

The sizes of craters formed on cylindrical, electro-polished, OFHC copper erosion specimens subjected to impact by closely-sized glass beads, average diameter 540 ?m, suspended in diesel oil in a slurry-pot erosion tester operating at nominal rotation speeds of 18.7, 14.0 and 9.35 m s?1 have been compared with those produced in an identical apparatus operating at the same speeds, in

Hector McI Clark

1995-01-01

206

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

207

The Impact of Farm Machinery Management on the Greenhouse Gas Emissions from Canadian Agriculture  

Microsoft Academic Search

The impact of proposed changes in field operations and land use on fossil fuel consumption on Canadian farms was analyzed using a computer model of the mechanics of farm machinery. The model predicted tractor\\/harvester power needs (kW), implement sizes and work required (kW-h) to complete each field operation on model farms in Canada's four farming regions. These predictions were integrated

J. A. Dyer; R. L. Desjardins

2003-01-01

208

Fuel-cycle greenhouse gas emissions impacts of alternative transportation fuels and advanced vehicle technologies.  

SciTech Connect

At an international conference on global warming, held in Kyoto, Japan, in December 1997, the United States committed to reduce its greenhouse gas (GHG) emissions by 7% over its 1990 level by the year 2012. To help achieve that goal, transportation GHG emissions need to be reduced. Using Argonne's fuel-cycle model, I estimated GHG emissions reduction potentials of various near- and long-term transportation technologies. The estimated per-mile GHG emissions results show that alternative transportation fuels and advanced vehicle technologies can help significantly reduce transportation GHG emissions. Of the near-term technologies evaluated in this study, electric vehicles; hybrid electric vehicles; compression-ignition, direct-injection vehicles; and E85 flexible fuel vehicles can reduce fuel-cycle GHG emissions by more than 25%, on the fuel-cycle basis. Electric vehicles powered by electricity generated primarily from nuclear and renewable sources can reduce GHG emissions by 80%. Other alternative fuels, such as compressed natural gas and liquefied petroleum gas, offer limited, but positive, GHG emission reduction benefits. Among the long-term technologies evaluated in this study, conventional spark ignition and compression ignition engines powered by alternative fuels and gasoline- and diesel-powered advanced vehicles can reduce GHG emissions by 10% to 30%. Ethanol dedicated vehicles, electric vehicles, hybrid electric vehicles, and fuel-cell vehicles can reduce GHG emissions by over 40%. Spark ignition engines and fuel-cell vehicles powered by cellulosic ethanol and solar hydrogen (for fuel-cell vehicles only) can reduce GHG emissions by over 80%. In conclusion, both near- and long-term alternative fuels and advanced transportation technologies can play a role in reducing the United States GHG emissions.

Wang, M. Q.

1998-12-16

209

Assessing environmental impact from gas and oil exploration in the SW Barents Sea using benthic foraminiferal assemblages  

NASA Astrophysics Data System (ADS)

During the last decades petroleum industry and shipping activities have increased in the SW Barents Sea. Oil exploration wells were drilled in the 1980s with production starting in 2007. These activities are projected to expand in the coming years. As part of the Northern Environmental Waste Management (EWMA) project, a competence cluster for petroleum industry related waste handling, we investigate the impacts of enhanced anthropogenic activities on benthic foraminiferal assemblages in the SW Barents Sea. Sediment cores (0-20 cm) from sites in proximity to two oil- and gas fields are under investigation. These sediment cores, dated with the 210Pb method, represent the last 90 to 150 years. Both dead and living benthic foraminifera (100 µm-1 mm) were counted to elucidate differences in foraminiferal assemblages between pre-impact and recent conditions. In addition, the heavy metal concentrations, persistent organic pollutant (POP) concentrations, grain size and total organic content (TOC) of the sediment cores have been analyzed. Pollution levels of the surface sediments (0-1 cm) are of background to good level (level I-II) according to the definitions of the Water Framework Directorate (WFD). Patterns in living benthic foraminiferal assemblages identified in the sea floor surface sediments, are the result of natural environmental changes such as depth, water mass and sediment composition. Further downcore (1-20 cm) pollution levels are in general of background environmental status (WFD level I). However, at some depth intervals, especially in sediment cores from the near proximity of the oil- and gas- fields, pollution levels are slightly enhanced (WFD level II). Further work will include statistical comparison of dead and living foraminiferal assemblages with sediment pollution levels, sediment properties, and oceanographic conditions. This research contributes to the development of foraminifera as a useful bio-monitoring technique for the Arctic region as industrial activities increase in the coming years.

Dijkstra, N.; Junttila, J.; Husum, K.; Carroll, J.; Hald, M.

2012-04-01

210

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; Hammerle, Martin; Moos, Ralf

2008-01-01

211

Impact of alkyl substituents on the gas-phase competition between substitution and elimination.  

PubMed

The S(N)2 and E2 reactions of a series of alkyl bromides with varying substitution patterns at the ?- and ?-carbons have been studied in the gas phase using naphthoate and phenoxide-based nucleophiles. The experimental work is supported by calculations at the MP2/6-31+G(d,p)//MP2/6-31+G(d) level. The results parallel reactivity patterns observed in the condensed phase, but offer new insights into steric factors in S(N)2 processes. In the gas phase, polarizability is more important, and the highest S(N)2 reactivity is observed when the ?-carbon is 2°. In addition, the data confirm that alkyl substituents at the ?-carbon have a greater accelerating effect on E2 reactions than those at the ?-carbon. Finally, computed data based on lowest enthalpy pathways provide poor descriptions of the reactions of the larger alkyl bromides and are skewed toward crowded systems that offer stabilizing, nonbonded interactions at the expense of conformational freedom. PMID:23895292

Conner, Keyanna M; Gronert, Scott

2013-09-01

212

Impact on aviation operations of volcanic gas and ash clouds from the 2008 eruptions of Okmok and Kasatochi, Alaska  

NASA Astrophysics Data System (ADS)

The eruptions of Okmok in July 2008 and Kasatochi in August 2008 both produced sulfur dioxide clouds notable for their dispersion over the northern conterminous United States. An aircraft encounter with the Okmok volcanic cloud occurred near Kodiak Island on 15 July, and some other flights were diverted north of normal air routes, but the overall impact on aviation of the Kasatochi eruption was greater. The 7 August 2008 eruption of Kasatochi sent an impressive amount of sulfur dioxide gas into the atmosphere, about 1.5 megatons according to S. Carn (this session), an order of magnitude greater than from Okmok. Preliminary estimates of Kasatochi's erupted volume range between 0.1 and 0.25 cubic kilometers (dense rock equivalent), making it one of the largest North American eruptions in the past 25 years. As Kasatochi's cloud dispersed over the Gulf of Alaska, Canada, and the northern conterminous United States, widespread disruptions to aviation operations occurred. On 10 August 2008 the ash/gas cloud passed over the southeast coast of Alaska, resulting in flight cancellations between Anchorage and Seattle, Portland, San Francisco, Denver, Los Angeles, and Vancouver BC and the stranding of a reported 6,000 passengers. The cancellations were primarily night flights, aa the airlines were concerned that pilots would not be able to visually identify the potentially hazardous volcanic cloud. As the cloud moved over Canada and parts of the United States, the area of sulfur dioxide detected by the satellite-borne Ozone Monitoring Instrument, while in accord with dispersion modeling by the Montreal Volcanic Ash Advisory Center, was much larger than the area of ash detected by the thermal infrared brightness-temperature-differencing (BTD) remote-sensing method. Concurrently, numerous pilot reports of sulfurous odors in the cockpit and visible brownish haze at cruise altitudes (the latter as late as two weeks after the eruption) suggested that sulfur dioxide gas had been converted to sulfur aerosols. Procedures for aircraft entry into volcanic ash clouds have been formulated, but procedures are not well specified for flying into large areas of sulfur dioxide gas and related aerosols. Airlines coped by flying over, under, and sometimes through the observable haze layer. Given the different types of data now available to detect and quantify ash, gas, and aerosols in the atmosphere, a focused scientific effort is needed to provide aviation users with integrated depictions of volcanic clouds so that appropriate operational procedures can be developed.

Guffanti, M.; Schneider, D. J.; Ewert, J. W.; Targosz, S.

2008-12-01

213

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

214

Impact on North Atlantic Winter Climate due to Changes of Greenhouse gas and Sulfate Aerosol Concentrations  

NASA Astrophysics Data System (ADS)

This study examines the future change of the North Atlantic winter climate influenced by increased concentrations of greenhouses gases and sulfate aerosol of anthropogenic origin. The direct effect of the aerosol on the clear sky radiative forcing and its climatic impact is investigated. Indirect aerosol effects are not considered in this study. Results of different climate simulations of an ocean/atmosphere general circulation model using IS92a (business-as-usual) type forcing are presented. Comparing the simulation forced with greenhouse gases alone with the simulation including aerosol forcing suggests that the aerosol has a significant impact on hydrological cycle and dynamics. Our results illustrate a similar but weaker response if the impact of the aerosol is considered in addition to greenhouses gases. Since the radiative forcing by sulfate is negative due to the backscattering of sunlight, the warming is attenuated if the sulfate aerosol comes into play. The simulations suggest that without the direct radiative effect of the aerosol, the North Atlantic climate would be warmer by about 1.2 K in winter. This temperature reduction has been diagnosed by averaging over the region 20°N- 80°N and 90°W-60°E and is statistically significant. Evaporation and precipitation are also reduced. However, significant differences occur only over some regions, especially over the Northeastern North Atlantic. The North Atlantic Oscillation (NAO) index has a reduced variability in the simulation including sulfate aerosol effects in a warming climate. There is also evidence that in this experiment fewer extreme NAO cases occur, which is associated with a reduction in storm activity and a decrease in the frequency of storm days.

Fischer-Bruns, I.; Feichter, J.

2007-05-01

215

Low temperature impact toughness of the main gas pipeline steel after long-term degradation  

NASA Astrophysics Data System (ADS)

The correlation of microstructure, temperature and Charpy V-notch impact properties of a steel 17G1S pipeline steel was investigated in this study. Within the concept of physical mesomechanics, the dynamic failure of specimens is represented as a successive process of the loss of shear stability, which takes place at different structural/scale levels of the material. Characteristic stages are analyzed for various modes of failure, moreover, typical levels of loading and oscillation periods, etc. are determined. Relations between low temperature derived through this test, microstructures and Charpy (V-notch) toughness test results are also discussed in this paper.

Maruschak, Pavlo O.; Danyliuk, Iryna M.; Bishchak, Roman T.; Vuherer, Tomaž

2014-12-01

216

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

217

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

218

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

219

The Impacts of a 2-Degree Rise in Global Temperatures upon Gas-Phase Air Pollutants in Europe  

NASA Astrophysics Data System (ADS)

The 15th session of the Conference of Parties (COP 15) in 2009 ratified the Copenhagen Accord, which "recognises the scientific view that" global temperature rise should be held below 2 degrees C above pre-industrial levels in order to limit the impacts of climate change. Due to the fact that a 2-degree limit has been frequently referred to by policy makers in the context of the Copenhagen Accord and many other high-level policy statements, it is important that the impacts of this 2-degree increase in temperature are adequately analysed. To this end, the European Union sponsored the project IMPACT2C, which uses a multi-disciplinary international team to assess a wide variety of impacts of a 2-degree rise in global temperatures. For example, this future increase in temperature is expected to have a significant influence upon meteorological conditions such as temperature, precipitation, and wind direction and intensity; which will in turn affect the production, deposition, and distribution of air pollutants. For the first part of the air quality analysis within the IMPACT2C project, the impact of meteorological forcings on gas phase air pollutants over Europe was studied using four offline atmospheric chemistry transport models. Two sets of meteorological forcings were used for each model: reanalysis of past observation data and global climate model output. Anthropogenic emissions of ozone precursors for the year 2005 were used for all simulations in order to isolate the impact of meteorology and assess the robustness of the results across the different models. The differences between the simulations that use reanalysis of past observation data and the simulations that use global climate model output show how global climate models modify climate hindcasts by boundary conditions inputs: information that is necessary in order to interpret simulations of future climate. The baseline results were assessed by comparison with AirBase (Version 7) measurement data, and were then used as a reference for an analysis of future climate scenarios upon European air quality. The future scenarios included two types of emission data for the year 2050: one set of emission data corresponding to a current legislation scenario and another corresponding to a scenario with a maximum feasible reduction in emissions. The future scenarios were run for the time period that corresponds to a 2-degree increase in global temperatures; a time period that varies depending on which global climate model is used. In order to calculate the effect of climate change on emission reduction scenarios, the "climate penalty", the future simulations were compared to a simulation using the same future emissions but with current (2005) climate. Results show that climate change will have consequential impacts with regards to the production and geographical distribution of ozone and nitrogen oxides.

Watson, Laura; Josse, Béatrice; Marecal, Virginie; Lacressonnière, Gwendoline; Vautard, Robert; Gauss, Michael; Engardt, Magnuz; Nyiri, Agnes; Siour, Guillaume

2014-05-01

220

The Impacts of Changes in Snowfall on Soil Greenhouse Gas Emissions Using an Automated Chamber System  

NASA Astrophysics Data System (ADS)

Snow cover has decreased in many regions of the northern hemisphere and is projected to decrease further in most. The reduced snow cover may enhance soil freezing and increase the depth of frost. The frequency of freeze-thaw cycles is likely to increase due to the reduction of snowpack thickness. Freeze and thaw cycles can strongly affect soil C and N dynamics. The pulses of N2O and CO2 emissions from soil after thawing have been reported in various studies. However, most studies were based on the controlled laboratory conditions or low resolution static chamber methods in situ. Near-continuous automated chambers provide the temporal resolution needed for capturing short-lived pulses of greenhouse gases after intermittent melting events. We investigated the winter and spring response of soil greenhouse gas emissions (CO2, CH4 and N2O) to changes of snow depth using an automated chamber system. This study was established in 2010 at the Kellogg Biological Station (KBS) in southwest Michigan. The plot was no till rotational (corn-soybean-wheat) cropland, most recently in corn. The experiment was a completely randomized design (CRD) with three levels of snow depth: ambient, double, and no snow. Each level had four replicates. Twelve automated chambers were randomly assigned to treatments and greenhouse gas fluxes measured 4 times per day in each plot. There were more freeze-thaw cycles in the no snow treatment than in the ambient and double snow treatments. Soil temperature at 5 cm depth was more variable in the no snow treatment than in the ambient and double snow treatments. CH4 fluxes were uniformly low with no significant difference across three treatments. CO2 showed expected seasonal changes with the highest emission in spring and lowest emissions through the winter. N2O peaks were higher in spring due to freeze thaw effects and cumulative N2O fluxes were substantially higher in the no snow treatment than in the ambient and double snow treatments.

Ruan, L.; Kahmark, K.; Robertson, G.

2012-12-01

221

DESIGNING AND CONDUCTING WORKSHOPS: LESSONS FROM A TWO-YEAR PROJECT (ONSHORE IMPACTS OF OUTER CONTINENTAL SHELF OIL AND GAS DEVELOPMENT: A TRAINING PROJECT)  

EPA Science Inventory

The report describes the process of developing and conducting two series of workshops on 'Onshore Impact of Outer Continental Shelf Oil and Gas Development'. The purpose of this report is to evaluate the workshops from the standpoint of their objectives, content, teaching methods...

222

Gas phase hydrolysis of formaldehyde to form methanediol: impact of formic acid catalysis.  

PubMed

We find that formic acid (FA) is very effective at facilitating diol formation through its ability to reduce the barrier for the formaldehyde (HCHO) hydrolysis reaction. The rate limiting step in the mechanism involves the isomerization of a prereactive collision complex formed through either the HCHO···H2O + FA and/or HCHO + FA···H2O pathways. The present study finds that the effective barrier height, defined as the difference between the zero-point vibrational energy (ZPE) corrected energy of the transition state (TS) and the HCHO···H2O + FA and HCHO + FA···H2O starting reagents, are respectively only ?1 and ?4 kcal/mol. These barriers are substantially lower than the ?17 kcal/mol barrier associated with the corresponding step in the hydrolysis of HCHO catalyzed by a single water molecule (HCHO + H2O + H2O). The significantly lower barrier heights for the formic acid catalyzed pathway reveal a new important role that organic acids play in the gas phase hydrolysis of atmospheric carbonyl compounds. PMID:23614454

Hazra, Montu K; Francisco, Joseph S; Sinha, Amitabha

2013-11-21

223

Impacts  

Microsoft Academic Search

Even without the impacts of climate change, water managers face prodigious challenges in meeting sustainable development goals. Growing populations need affordable food, water and energy. Industrial development demands a growing share of water resources and contaminates those same resources with its untreated wastes. Nature is at the back of the queue, but preserving enough flows to sustain aquatic ecosystems is

M. Hellmuth; P. Kabat

2003-01-01

224

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

225

Greenhouse gas emissions from MSW incineration in China: impacts of waste characteristics and energy recovery.  

PubMed

Determination of the amount of greenhouse gas (GHG) emitted during municipal solid waste incineration (MSWI) is complex because both contributions and savings of GHGs exist in the process. To identify the critical factors influencing GHG emissions from MSWI in China, a GHG accounting model was established and applied to six Chinese cities located in different regions. The results showed that MSWI in most of the cities was the source of GHGs, with emissions of 25-207 kg CO(2)-eq t(-1) rw. Within all process stages, the emission of fossil CO(2) from the combustion of MSW was the main contributor (111-254 kg CO(2)-eq t(-1) rw), while the substitution of electricity reduced the GHG emissions by 150-247 kg CO(2)-eq t(-1) rw. By affecting the fossil carbon content and the lower heating value of the waste, the contents of plastic and food waste in the MSW were the critical factors influencing GHG emissions of MSWI. Decreasing food waste content in MSW by half will significantly reduce the GHG emissions from MSWI, and such a reduction will convert MSWI in Urumqi and Tianjin from GHG sources to GHG sinks. Comparison of the GHG emissions in the six Chinese cities with those in European countries revealed that higher energy recovery efficiency in Europe induced much greater reductions in GHG emissions. Recovering the excess heat after generation of electricity would be a good measure to convert MSWI in all the six cities evaluated herein into sinks of GHGs. PMID:22796016

Yang, Na; Zhang, Hua; Chen, Miao; Shao, Li-Ming; He, Pin-Jing

2012-12-01

226

Greenhouse gas emissions from MSW incineration in China: Impacts of waste characteristics and energy recovery  

SciTech Connect

Determination of the amount of greenhouse gas (GHG) emitted during municipal solid waste incineration (MSWI) is complex because both contributions and savings of GHGs exist in the process. To identify the critical factors influencing GHG emissions from MSWI in China, a GHG accounting model was established and applied to six Chinese cities located in different regions. The results showed that MSWI in most of the cities was the source of GHGs, with emissions of 25-207 kg CO{sub 2}-eq t{sup -1} rw. Within all process stages, the emission of fossil CO{sub 2} from the combustion of MSW was the main contributor (111-254 kg CO{sub 2}-eq t{sup -1} rw), while the substitution of electricity reduced the GHG emissions by 150-247 kg CO{sub 2}-eq t{sup -1} rw. By affecting the fossil carbon content and the lower heating value of the waste, the contents of plastic and food waste in the MSW were the critical factors influencing GHG emissions of MSWI. Decreasing food waste content in MSW by half will significantly reduce the GHG emissions from MSWI, and such a reduction will convert MSWI in Urumqi and Tianjin from GHG sources to GHG sinks. Comparison of the GHG emissions in the six Chinese cities with those in European countries revealed that higher energy recovery efficiency in Europe induced much greater reductions in GHG emissions. Recovering the excess heat after generation of electricity would be a good measure to convert MSWI in all the six cities evaluated herein into sinks of GHGs.

Yang Na [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Zhang Hua, E-mail: zhanghua_tj@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Chen Miao; Shao Liming [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); He Pinjing, E-mail: xhpjk@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China)

2012-12-15

227

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

228

Polybrominated diphenyl ether flame retardants in the antarctic environment  

E-print Network

hemisphere and Antarctica. The analyses reported in this dissertation document the levels of PBDEs in lichens, mosses and seabird eggs collected at King George Island, Antarctic Peninsula. The analyses were carried out using Gas Chromatography/Electron Impact...

Yogui, Gilvan Takeshi

2009-05-15

229

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

230

Impact of operating conditions on performance of a novel gas double-dynamic solid-state fermentation bioreactor (GDSFB).  

PubMed

A self-designed novel solid-state fermentation (SSF) bioreactor named "gas double-dynamic solid-state fermentation bioreactor (GDSFB)" showed great success in processes for the production of several valuable products. For the present study, a simple GDSFB (2 L in volume) was designed to investigate the impact of exhaust time on SSF performance. Both air pressure and vent aperture significantly influenced the exhaust time. The production of cellulase by Penicillium decumbens JUA10 was studied in this bioreactor. When the vent aperture was maintained at 0.2 cm, the highest FPA activity of 17.2 IU/g dry solid-state medium was obtained at an air pressure of 0.2 MPa (gauge pressure). When the air pressure was maintained at 0.2 MPa, a vent aperture of 0.3 cm gave the highest FPA activity of 18.0 IU/g dry solid-state medium. Further analysis revealed that the exhaust time was a crucial indicator of good performance in GDSFB. PMID:23579630

Chen, Hongzhang; Li, Yanjun; Xu, Fujian

2013-11-01

231

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

232

The impact of ambient gas on the magnetic properties of Ti 40Zr 40Ni 20 powders during mechanical alloying  

NASA Astrophysics Data System (ADS)

Ti 40Zr 40Ni 20 in the form of elemental powders was mechanically alloyed in a planetary ball-mill under argon and hydrogen atmospheres at an acceleration of 55 m s -2 for different time intervals. The samples were analyzed by X-ray diffraction (XRD), vibrating-sample magnetometry (VSM) and scanning electron microscopy (SEM), which revealed the large impact of the ambient gas, i.e. argon and hydrogen, on the magnetic properties, morphology and structure. Namely, during mechanical alloying in argon the saturation magnetization decreased due to the modification of the Ni d-states upon alloying with paramagnetic Ti and Zr, whereas in hydrogen the Ni d-states remained largely unmodified, since the formation of TiH 2 and ZrH 2 was faster than the alloying with the ferromagnetic nickel. However, after 40 h we obtained a mixture of nanocrystalline Ni and ZrH 2/TiH 2 hydrides, which in equilibrium contained 1.55 mass% of hydrogen. In the case of argon we determined welding of the Ti 40Zr 40Ni 20 amorphous particles, whereas in hydrogen such a process was suppressed by the brittle ZrH 2/TiH 2 hydrides. In addition, we revealed that the mechanical alloying of pure Ni powder for 100 h in argon does not affect its magnetic properties.

Kocjan, A.; McGuiness, P. J.; Kobe, S.

2011-02-01

233

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

234

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

235

Screening of beta-blockers in human serum by ion-pair chromatography and their identification as methyl or acetyl derivatives by gas chromatography-mass spectrometry.  

PubMed

A simultaneous screening method for atenolol, acebutolol, metoprolol, oxprenolol, alprenolol and propranolol by ion-pair chromatography with a column-switching technique was developed. The serum samples were purified using either liquid-liquid extraction or solid-phase extraction methods. The pretreatment of the samples consisted of hydrolysis and protein precipitation. The drug separation was on either octadecylsilica or polymer-based alkyl column material. Binary eluent mixtures containing methanol and a buffer solution with a quaternary ammonium salt as an ion-pair former were used. Detection of the compounds in liquid chromatographic analysis was based on ultraviolet spectra. The effects of methanol, two buffers and the ion-pair former on the retention of the compounds were studied. The determination limits ranged from nanograms to micrograms in the ion-pair chromatographic method, depending on the drug studied. Identification was based on the mass spectra or, if necessary, on selected-ion monitoring spectra of either the methylated or the acetylated compounds obtained by means of gas chromatography-electron impact or negative chemical ionization mass spectrometry. The detection limits for the identified compounds were in the picogram range. The matrix effect was strong, and this resulted in determination limits in the nanogram range with the scan method. PMID:8095938

Sirén, H; Saarinen, M; Hainari, S; Lukkari, P; Riekkola, M L

1993-02-19

236

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

Federal Register 2010, 2011, 2012, 2013

...Statement for Effects of Oil and Gas Activities in the Arctic Ocean AGENCY: National Marine Fisheries Service (NMFS...DEIS) for the Effects of Oil and Gas Activities in the Arctic Ocean.'' Based on a written request received by...

2013-04-10

237

77 FR 2513 - Draft Environmental Impact Statement for Effects of Oil and Gas Activities in the Arctic Ocean  

Federal Register 2010, 2011, 2012, 2013

...Statement for Effects of Oil and Gas Activities in the Arctic Ocean AGENCY: National Marine Fisheries Service (NMFS...DEIS) for the Effects of Oil and Gas Activities in the Arctic Ocean.'' Based on several written requests received...

2012-01-18

238

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

239

Effect of increased ambient temperature on the growth rate of young pine forests in the impact zone of a petroleum gas flare  

Microsoft Academic Search

The effect of increased ambient temperature on the vertical, radial, and volume increments of Scots pine (Pinus sylvestris L.) trees has been studied in the zone of thermal impact from a burning petroleum gas flare. Regular age-dependent changes\\u000a in the pattern of increment dependence on the distance from the flare and ambient temperature have been revealed. The mechanisms\\u000a of these

S. A. Shavnin; I. A. Yusupov; A. A. Montile; D. Yu. Golikov; A. I. Montile

2009-01-01

240

Metal contamination of surface water, sediment and Tympanotonus fuscatus var. radula of Iko River and environmental impact due to Utapete gas flare station, Nigeria  

Microsoft Academic Search

Inter-seasonal studies on the trace metal load of surface water, sediment and Tympanotonus fuscatus var. radula of Iko River were conducted between 2003 and 2004. The impact of anthropogenic activities especially industrial effluent,\\u000a petroleum related wastes, gas flare and episodic oil spills on the ecosystem are remarkable. Trace metals analyzed included\\u000a cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead

Nsikak U. Benson; Usoro M. Etesin

2008-01-01

241

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

242

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

243

Impact of the gas flow ratio on the physical properties of GaN grown by vertical flow metalorganic chemical vapour deposition  

NASA Astrophysics Data System (ADS)

We studied the effect of gas flow ratio of the H 2 carrier gas to the NH 3 precursor on the physical and crystal properties of GaN. GaN was grown by vertical reactor metalorganic chemical vapour deposition (MOCVD) on a low-temperature-deposited GaN buffer layer. A (0 0 0 1) sapphire substrate was used. The impact of the gas flow ratio as it was varied from 0.25 to 1 was investigated and discussed. With increase in flow ratio, the concentrations of magnesium and carbon impurities in GaN increased. The flow ratio of 0.5 is the optimum value to minimise the background electron concentration and to maintain crystal quality. The decrease in the background electron concentration is due to the compensation mechanism of acceptor-like magnesium and carbon impurities.

Yuan, Tzu-Tao; Kuei, Ping-Yu; Hsieh, Li-Zen; Li, Ta-Ching; Lin, Wen-Jen

2010-07-01

244

Arctic summary report. Outer Continental Shelf and onshore oil and gas activities and impacts in the Arctic: a summary report, October 1981. Arctic summary report  

SciTech Connect

This summary report begins with a chapter describing the Arctic subregion. Sections of this chapter discuss the geology of the area, including the most recent OCS oil and gas resource and reserve estimates, climate, sand and gravel, the biological environment, the people, and current land use. The magnitude and timing of oil and gas activity are discussed in chapter 2. The third chapter presents information on oil and gas transportation strategies. Chapter 4 describes the nearshore and onshore facilities and impacts that are occurring and/or probably will occur as a result of current and projected lease sales. Appendixes provide further detail, and a glossary presents definitions of geologic, industry-specific, and other special terms used in the report. OCS resource and reserve estimates presented in the summary report reflect the most recent Federal Government information.

Jackson, J.B.; Golden, B.F.; Stadnychenko, A.; Kolasinski, S.

1981-01-01

245

Multiresidue method for the simultaneous determination of four groups of pesticides in ground and drinking waters, using solid-phase microextraction–gas chromatography with electron-capture and thermionic specific detection  

Microsoft Academic Search

A common sample preparation procedure capable of efficiently concentrating various groups of pesticides, taking advantage of universal detectors like the mass spectrometer or combined techniques of group selective detectors like gas chromatography–electron capture detection (ECD)\\/thermionic specific detection (TSD), is desirable in environmental analysis. Six solid-phase microextraction fibres available for analysis of semi-volatiles (7, 30 and 100 ?m poly(dimethylsiloxane) (PDMS), 85

C Gonçalves; M. F Alpendurada

2002-01-01

246

Landowner Attitudes and Perceptions of Impact from Wind and Natural Gas Development in Northern Pennsylvania: Implications for Energy Landscapes in Rural America  

NASA Astrophysics Data System (ADS)

Energy developments such as industrial scale wind farms and unconventional natural gas drilling represent some of the largest and most controversial land use changes occurring in the United States today. A diverse array of academic disciplines have each sought to explain the social, psychological, and economic effects of siting large industrial facilities in rural areas, however the research has largely remained discipline-specific. This study measures resident attitudes and perceptions of impact from both wind and gas drilling occurring simultaneously in the Armenia Mountain Area of northern Pennsylvania. The results of a mail survey of landowners (n = 1028) in this study area reveal factors that explain landowner variation in attitudes and perception of impact, and describe new forms of participation in the planning and siting of these energy projects. Direction is provided for a new and synthetic theoretical understanding of how residents perceive these impacts and impacts from land use change. The work advances “risk of social and psychological disruption” as a key factor that may influence how residents respond to the prospect of large land use changes. Implications for the regulation and planning of these energy sources are offered, including a new understanding of how landowners participate in the planning and siting of large energy projects. Finally, the limitations of this work, as well as opportunities and implications for future research, are discussed.

Jacquet, Jeffrey Bryan

247

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

248

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

249

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

250

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

251

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

252

Single microparticle launching method using two-stage light-gas gun for simulating hypervelocity impacts of micrometeoroids and space debris  

SciTech Connect

A single microparticle launching method is described to simulate the hypervelocity impacts of micrometeoroids and microdebris on space structures at the Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency. A microparticle placed in a sabot with slits is accelerated using a rifled two-stage light-gas gun. The centrifugal force provided by the rifling in the launch tube separates the sabot. The sabot-separation distance and the impact-point deviation are strongly affected by the combination of the sabot diameter and the bore diameter, and by the projectile diameter. Using this method, spherical projectiles of 1.0-0.1 mm diameter were launched at up to 7 km/s.

Kawai, Nobuaki; Tsurui, Kenji; Hasegawa, Sunao; Sato, Eiichi [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan)

2010-11-15

253

[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

254

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

NASA Technical Reports Server (NTRS)

Under the Federal Aviation Administration's Airworthiness Assurance Center of Excellence and the Aircraft Catastrophic Failure Prevention Program, National Aeronautics and Space Administration Glenn Research Center collaborated with Arizona State University, Honeywell Engines, Systems and Services, and SRI International to develop improved computational models for designing fabric-based engine containment systems. In the study described in this report, ballistic impact tests were conducted on layered dry fabric rings to provide impact response data for calibrating and verifying the improved numerical models. This report provides data on projectile velocity, impact and residual energy, and fabric deformation for a number of different test conditions.

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

2004-01-01

255

77 FR 47052 - El Paso Natural Gas Company; Notice of Intent To Prepare an Environmental Impact Statement for...  

Federal Register 2010, 2011, 2012, 2013

...right-of-way after construction; Impacts on threatened and endangered species (including the masked bobwhite quail, Pima pineapple cactus, and Chiricahua leopard frog) and other sensitive species (including the cactus ferruginous pygmy owl); and...

2012-08-07

256

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

257

Impact of hot fluid advection on hydrocarbon gas production and seepage in mud volcano sediments of thick Cenozoic deltas  

NASA Astrophysics Data System (ADS)

Hydrocarbon seeps are ubiquitous at gas-prone Cenozoic deltas such as the Nile Deep Sea Fan (NDSF) On the contrary at the periphery, a lower but sustained CH4 flux is indicated by deeper sulphate-methane transition zones and the presence of 13C-depleted biomarkers of AOM, consistent with predominantly immature organic matter. Values of ?13C-CH4?-60‰VPDB and decreased concentrations of 13C-enriched C2+ are typical of mixed microbial CH4 and biodegraded thermogenic gas from Plio-Pleistocene reservoirs of the region. The maturity of gas condensate migrated from pre-Miocene sources into Miocene reservoirs of the Western NDSF is higher than that of the gas vented at the centre of NAMV, supporting the hypothesis that it is rather released from the degradation of oil in Neogene reservoirs. Combined with the finding of hot pore water and petroleum at the centre, our results suggest that clay mineral dehydration of Neogene sediments, which takes place posterior to reservoir filling, may contribute to intense gas generation at high sedimentation rate deltas.

Nuzzo, Marianne; Elvert, Marcus; Schmidt, Mark; Scholz, Florian; Reitz, Anja; Hinrichs, Kai-Uwe; Hensen, Christian

2012-08-01

258

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

259

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

260

Fundamental insights on impact of non-condensible gas evolution from coating pyrolysis and intentional injection on molten-aluminum water explosion onset during direct-chill casting  

SciTech Connect

Explosive interactions between molten aluminum and water are being studied with a focus on fundamentals to determine what causes robust-enough triggers for explosion onset, to determine the extent of protection provided from various coatings and to develop a fundamentally-based simple, cost-effective novel methodology for prevention. The workscope includes experimentation and mathematical modeling of the interactions between molten metals and water at various different coated and uncoated surfaces. Phenomenological issues related to surface wettability, gas generation from coatings, charring of coatings, inertial constraint, melt temperature, water temperature, external shocks are being investigated systematically to gage their relative impact on the triggerability of surface-assisted steam explosions. The steam explosion triggering studies (SETS) facility was designed and constructed as a rapid-turnaround, cost-effective, and safe means to address these phenomenological issues. Data from SETS tests have indicated that, non-condensible gas (NCG) generation during paint pyrolysis plays a predominant role in explosion prevention. This paper describes results of studies on impact of deliberate NCG injection on explosion prevention, via molten melt drops free-falling into water, as well as from tests using the SETS facility for studying entrapment induced explosive boiling. SETS is also being used to obtain information on time-varying and integral amounts of NCGs generated from various paints. Relevant data are presented. Results of investigations, taken together provide compelling evidence on the positive role NCGs play on explosion prevention.

Taleyarkhan, R.P.; Kim, S.H. [Oak Ridge National Lab., TN (United States); Gulec, K. [Oak Ridge Associated Universities, TN (United States)

1998-05-01

261

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 one of the biggest onshore European reservoir and the largest oil/gas pre-treatment plant, named Centro Olio Val d'Agri (COVA), located in a rural/anthropized context. Several hazards are associated with this plant. These are mainly represented by possible impacts of the COVA atmospheric emissions on the local air quality and human health. This work uses a novel approach based on the integration of air quality measurements from the regional monitoring network, additional experimental measurements (i.e. sub-micrometre particulate matter (PM1) and black carbon (BC)) and advanced statistical analyses to provide a preliminary evaluation of the Val d'Agri air quality state and give some indication of specific areas potentially affected by COVA hazards. Results show that the COVA plant emissions have a particular impact on the air quality of the area closest to it. In this area several pollutants specifically related to the COVA combustion processes (i.e. nitrogen oxides, benzene and toluene) show the highest concentration values and significant correlations. The proposed approach represents a first step in the assessment of the risks associated with oil/gas exploration and pre-treatment activities and a starting point for the development of effective and exportable air quality monitoring strategies.

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

2014-08-01

262

Impact of oil and gas vents and slicks on petroleum exploration in the deepwater Gulf of Mexico  

Microsoft Academic Search

Active petroleum vents and slicks have been identified in the deep water of the northern Gulf of Mexico using numerous techniques. The occurrence and distribution of these petroleum vents are strongly influenced by the local geological framework—especially the presence of vertical migration pathways into shallow sediments. Oil and gas vents may be more useful for establishing the existence of petroleum

A. S. Kornacki; J. W. Kendrick; J. L. Berry

1994-01-01

263

Biodegradation of gas-phase styrene using the fungus Sporothrix variecibatus: impact of pollutant load and transient operation.  

PubMed

Biofiltration of gas-phase styrene was studied using a newly isolated fungus Sporothrix variecibatus, in a perlite biofilter, at inlet concentrations and gas-flow rates ranging from 0.13 to 14 g m(-3) and 0.075 to 0.34 m(3) h(-1), respectively, corresponding to empty bed residence times (EBRT) ranging between 91 and 20s. Styrene loading rates were varied between 50 and 845 g m(-3) h(-1)and a maximum elimination capacity of 336 g m(-3) h(-1) was attained with nearly 65% styrene removal. On the other hand, the critical inlet loads to achieve more than 90% removal were 301, 240 and 92 g m(-3) h(-1) for EBRT of 91, 40, and 20s, respectively. In order to test the stability and shock bearing capacity of the fungal biofilter, short-term tests were conducted by suddenly increasing the gas-phase styrene concentration, while maintaining the gas-flow rate constant. The response, a restoration in the removal performance to previous high values, after subjecting the biofilter to shock loads proves the resilient nature of the attached Sporothrix sp. and its suitability for biofiltration under non-steady state conditions. PMID:20149411

Rene, Eldon R; Veiga, María C; Kennes, Christian

2010-03-01

264

Strategies for carbon dioxide emissions reductions: Residential natural gas efficiency, economic, and ancillary health impacts in Maryland  

Microsoft Academic Search

As part of its commitments to the Regional Greenhouse Gas Initiative (RGGI), the State of Maryland, USA, auctions emission permits to electric utilities, creating revenue that can be used to benefit consumers and the environment. This paper explores the CO2 emissions reductions that may be possible by allocating some of that revenue to foster efficiency improvements in the residential sector’s

Matthias Ruth; Andrew Blohm; Joanna Mauer; Steven A. Gabriel; Vijay G. Kesana; Yihsu Chen; Benjamin F. Hobbs; Daraius Irani

2010-01-01

265

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

266

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

267

An analytical investigation of 24 oxygenated-PAHs (OPAHs) using liquid and gas chromatography-mass spectrometry.  

PubMed

We developed two independent approaches for separation and quantitation of 24 oxygenated polycyclic aromatic hydrocarbons (OPAHs) using both liquid chromatography-atmospheric pressure chemical ionization/mass spectrometry (LC-APCI/MS) and gas chromatography-electron impact/mass spectrometry (GC-EI/MS). Building on previous OPAH research, we examined laboratory stability of OPAHs, improved existing method parameters, and compared quantification strategies using standard addition and an internal standard on an environmental sample. Of 24 OPAHs targeted in this research, 19 compounds are shared between methods, with 3 uniquely quantitated by GC-EI/MS and 2 by LC-APCI/MS. Using calibration standards, all GC-EI/MS OPAHs were within 15 % of the true value and had less than 15 % relative standard deviations (RSDs) for interday variability. Similarly, all LC-APCI/MS OPAHs were within 20 % of the true value and had less than 15 % RSDs for interday variability. Instrument limits of detection ranged from 0.18 to 36 ng mL(-1) on the GC-EI/MS and 2.6 to 26 ng mL(-1) on the LC-APCI/MS. Four standard reference materials were analyzed with each method, and we report some compounds not previously published in these materials, such as perinaphthenone and xanthone. Finally, an environmental passive sampling extract from Portland Harbor Superfund, OR was analyzed by each method using both internal standard and standard addition to compensate for potential matrix effects. Internal standard quantitation resulted in increased precision with similar accuracy to standard addition for most OPAHs using 2-fluoro-fluorenone-(13)C as an internal standard. Overall, this work improves upon OPAH analytical methods and provides some considerations and strategies for OPAHs as focus continues to expand on this emerging chemical class. PMID:24005604

O'Connell, Steven G; Haigh, Theodore; Wilson, Glenn; Anderson, Kim A

2013-11-01

268

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

269

Technology choice in a least-cost expansion analysis framework: The impact of gas prices, planning horizon, and system characteristics  

SciTech Connect

The current outlook for new capacity addition by electric utilities is uncertain and tenuous. Regardless of the amount, it is inevitable that new capacity will be needed in the 1990s and beyond. The fundamental question about the addition capacity requirements centers on technology choice and the factors influencing the decision process. We examined technology choices in 10 representative power pools with a dynamic optimization expansion model, the Wien Automatic System Planning (WASP) Package. These 10 power pools were determined to be representative on the basis of a cluster analysis conducted on all 26 power pools in the United States. A least-cost expansion plan was determined for each power pool with three candidate technologies--natural gas combustion turbine (CT), natural gas combined cycle (NGCC), and integrated gasification combined cycle (IGCC)--three alternative gas price tracks, and two planning horizons between the years 1995 and 2020. This paper summarizes the analysis framework and presents results for Power Pool 1, the American Electric Power (AEP) service territory. 7 refs., 9 figs., 1 tab.

Guziel, K.A.; South, D.W.

1990-01-01

270

Large-scale shock-ionized and photo-ionized gas in M83: the impact of star formation  

E-print Network

We investigate the ionization structure of the nebular gas in M83 using the line diagnostic diagram, [O III](5007 \\degA)/H{\\beta} vs. [S II](6716 \\deg A+6731 \\deg 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. For the photo-ionized 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 photo-ionized from the shock-ionized component of the gas. We find that the shock-ionized H{\\alpha} emission ranges from ~2% to about 15-33% of the total, depending on the separation criteria used. An interesting feature in the diagnostic diagram is an horizontal distribution aro...

Hong, Sungryong; Dopita, Michael A; Blair, William P; Whitmore, Bradley C; Balick, Bruce; Bond, Howard E; Carollo, Marcella; Disney, Michael J; Frogel, Jay A; Hall, Donald; Holtzman, Jon A; Kimble, Randy A; McCarthy, Patrick J; O'Connell, Robert W; Paresce, Francesco; Saha, Abhijit; Silk, Joseph I; Trauger, John T; Walker, Alistair R; Windhorst, Rogier A; Young, Erick T; Mutchler, Max

2011-01-01

271

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

272

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

273

Gulf of Mexico summary report 3. A revision of Outer Continental Shelf oil and gas activities in the Gulf of Mexico and their onshore impacts: Gulf of Mexico summary report 2, August 1981  

Microsoft Academic Search

This report is the latest in a series of annual reports summarizing current oil and gas activities in the Gulf of Mexico OCS and their onshore impacts. Oil production for 1981 was 0.27 billion barrels, and gas production was 4.84 trillion cubic feet. Most of the shallow-water areas of the Gulf of Mexico Continental Shelf have been explored. Industry has

K. J. Havran; J. D. Wiese; K. M. Collins; F. N. Kurz

1982-01-01

274

Impact of resonance regeneration and decay on the net-proton fluctuations in a hadron resonance gas  

E-print Network

We investigate net-proton fluctuations as important observables measured in heavy-ion collisions within the hadron resonance gas (HRG) model. Special emphasis is given to effects which are a priori not inherent in a thermally and chemically equilibrated HRG approach. In particular, we point out the importance of taking into account the successive regeneration and decay of resonances below the chemical freeze-out, which lead to a randomization of the isospin of nucleons and thus to additional fluctuations in the net-proton number. We find good agreement between our model results and the recent STAR measurements of the higher-order moments of the net-proton distribution.

Marlene Nahrgang; Marcus Bluhm; Paolo Alba; Rene Bellwied; Claudia Ratti

2014-02-06

275

Impact of resonance regeneration and decay on the net-proton fluctuations in a hadron resonance gas  

E-print Network

We investigate net-proton fluctuations as important observables measured in heavy-ion collisions within the hadron resonance gas (HRG) model. Special emphasis is given to effects which are a priori not inherent in a thermally and chemically equilibrated HRG approach. In particular, we point out the importance of taking into account the successive regeneration and decay of resonances below the chemical freeze-out, which lead to a randomization of the isospin of nucleons and thus to additional fluctuations in the net-proton number. We find good agreement between our model results and the recent STAR measurements of the higher-order moments of the net-proton distribution.

Nahrgang, Marlene; Alba, Paolo; Bellwied, Rene; Ratti, Claudia

2014-01-01

276

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

277

NATURAL GAS VARIABILITY IN CALIFORNIA: ENVIRONMENTAL IMPACTS AND DEVICE PERFORMANCE EXPERIMENTAL EVALUATION OF POLLUTANT EMISSIONS FROM RESIDENTIAL APPLIANCES  

SciTech Connect

The effect of liquefied natural gas on pollutant emissions was evaluated experimentally with used and new appliances in the laboratory and with appliances installed in residences, targeting information gaps from previous studies. Burner selection targeted available technologies that are projected to comprise the majority of installed appliances over the next decade. Experiments were conducted on 13 cooktop sets, 12 ovens, 5 broiler burners, 5 storage water heaters, 4 forced air furnaces, 1 wall furnace, and 6 tankless water heaters. Air-free concentrations and fuel-based emission factors were determined for carbon monoxide, nitrogen oxides, nitrogen dioxide, and the number of (predominantly ultrafine) particles over complete burns?including transient effects (device warm-up and intermittent firing of burners) following ignition--and during more stable end-of-burn conditions. Formaldehyde was measured over multi-burn cycles. The baseline fuel was Northern California line gas with Wobbe number (a measure of fuel energy delivery rate) of 1320-1340; test fuels had Wobbe numbers of roughly 1390 and 1420, and in some cases 1360. No ignition or operational problems were observed during test fuel use. Baseline emissions varied widely across and within burner groups and with burner operational mode. Statistically significant emissions changes were observed for some pollutants on some burners.

Singer, Brett C.; Apte, Michael G.; Black, Douglas R.; Hotchi, Toshifumi; Lucas, Donald; Lunden, Melissa M.; Mirer, Anna G.; Spears, Michael; Sullivan, Douglas P.

2009-12-01

278

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

279

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

280

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

281

Impact of gas-phase mechanisms on Weather Research Forecasting Model with Chemistry (WRF/Chem) predictions: Mechanism implementation and comparative evaluation  

NASA Astrophysics Data System (ADS)

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 conducted over the continental United States for July 2001, with three different gas-phase mechanisms, a default one (i.e., CBM-Z) and two newly implemented ones (i.e., CB05 and SAPRC-99). Simulation results are evaluated against available surface observations, satellite data, and reanalysis data. The model with these three gas-phase mechanisms gives similar predictions of most meteorological variables in terms of spatial distribution and statistics, but large differences exist in shortwave radiation and temperature and relative humidity at 2 m at individual sites under cloudy conditions, indicating the importance of aerosol semi-direct and indirect effects on these variables. Large biases exist in the simulated wind speed at 10 m, cloud water path, cloud optical thickness, and precipitation, due to uncertainties in current cloud microphysics and surface layer parameterizations. Simulations with all three gas-phase mechanisms well reproduce surface concentrations of O3, CO, NO2, and PM2.5, and column NO2. Larger biases exist in the surface concentrations of nitrate and organic matter (OM) and in the spatial distribution of column CO, tropospheric ozone residual, and aerosol optical depth, due to uncertainties in primary OM emissions, limitations in model representations of chemical transport, and radiative processes. Different gas-phase mechanisms lead to different predictions of mass concentrations of O3 (up to 5 ppb), PM2.5 (up to 0.5 ?g m-3), secondary inorganic PM2.5 species (up to 1.1 ?g m-3), organic PM (up to 1.8 ?g m-3), and number concentration of PM2.5 (up to 2 × 104 cm-3). Differences in aerosol mass and number concentrations further lead to sizeable differences in simulated cloud condensation nuclei (CCN) and cloud droplet number concentration (CDNC) due to the feedback mechanisms among H2SO4 vapor, PM2.5 number, CCN, and CDNC through gas-phase chemistry, new particle formation via homogeneous nucleation, aerosol growth, and aerosol activation by cloud droplets. This study illustrates the important impact of gas-phase mechanisms on chemical and aerosol predictions, their subsequent effects on meteorological predictions, and a need for an accurate representation of such feedbacks through various atmospheric processes in the model. The online-coupled models that simulate feedbacks between meteorological variables and chemical species may provide more accurate representations of the real atmosphere for regulatory applications and can be applied to simulate chemistry-climate feedbacks over a longer period of time.

Zhang, Yang; Chen, Yaosheng; Sarwar, Golam; Schere, Kenneth

2012-01-01

282

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

283

The dynamical evolution of circumstellar gas around massive stars. I. The impact of the time sequence Ostar -> LBV -> WR star.  

NASA Astrophysics Data System (ADS)

We show that computation of the behavior of circumstellar gas provides a powerful tool for the investigation of stellar mass loss history. Our computations allow us to add a new dimension to the Hertzsprung-Russell diagram by including the existence and size of circumstellar nebulae as an additional diagnostic of stellar evolution. As a first example, we follow the dynamics of the interaction of a 60Msun_ star (Langer et al. 1994) with its circumstellar medium over its entire lifetime. We use an implicit hydrodynamic code for massive stellar evolution to provide the inner boundary conditions for an explicit hydrodynamic code to model the circumstellar gas dynamics. The final supernova phase is not included. Our computations predict short-lived (?=~10^4^yr) observable nebulae during the luminous blue variable (LBV) stage and the onset of the Wolf-Rayet stage. Small scale features of ring nebulae can also give insight into the preceding stellar wind evolution. We find that variations in the stellar wind drive an instability that produces radial filaments in ring nebulae. The filaments maintain an almost steady angular spacing, but grow radially. This may explain the short angular spacing and comet-like tails of clumps observed in ring nebulae surrounding massive stars such as RCW 58 or AG Carinae. This instability may also explain the clumps observed in several planetary nebulae such as the Helix nebula and NGC 2392. Furthermore, the double shell structure found in our computations resembles that observed in ? Carinae. Finally, we obtain a fragmented circumstellar nebula in our model for the LBV phase corresponding to P Cygni.

Garcia-Segura, G.; Mac Low, M.-M.; Langer, N.

1996-01-01

284

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

285

Integration of Satellite Estimates of Daily Inundation Extent into a Land Surface Ecosystem-Atmosphere Gas Exchange Model: Impacts on Methane Modeling  

NASA Astrophysics Data System (ADS)

Soil moisture and the spatial extent of soil saturation, transient inundation, and wetland ecosystems are key determinants of greenhouse gas (GHG, e.g., methane) emissions from the land surface to the atmosphere. We are investigating how near-daily surface water and soil moisture observations such as those expected from NASA's planned Soil Moisture Active-Passive (SMAP) mission could be integrated into an ecosystem-atmosphere gas exchange model to improve its estimates of GHG fluxes. SMAP, to be launched in November 2014, will combine ~3-km resolution synthetic aperture radar (SAR), ~40-km-resolution L-band radiometry, and 3-day revisit period to make a novel dataset expected to provide inundation and soil moisture estimates superior to alternative methods at that temporal-spatial scale. We test the potential impact of this new data source using the Dynamic Land Surface Ecosystem Model (DLEM). DLEM quantifies regional fluxes of methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) given atmospheric forcing data, with soil saturation as a prognostic variable. In this presentation, we discuss the results of integrating DLEM CH4 emission model products with time-varying subgrid inundation extent estimates from satellite remote sensing observations of North America. To emulate SMAP observations, we have derived a new daily inundation fraction dataset for 2008-2010 using data from NASA's Advanced Microwave Scanning Radiometer-EOS (AMSR-E). To test data-model integration, we created a testbed composed of two separate multi-year DLEM runs in which subgrid land cover conditions were artificially prescribed: one run with maximum wetlands coverage and one with no wetlands. We can combine CH4 products from the two runs using our daily inundation fraction estimates or other inundation representations such that the combination approximates CH4 flux results from a model with explicit inundation forcing. The testbed allows us to simulate a larger array of mixed-grid cases than would be possible with individual model runs explicitly forced by different daily inundation data inputs. Here, we compare CH4 flux results representing two model-data integration realizations: one in which the saturated wetlands coverage is held constant (i.e., representing persistent wetlands) and one in which it is allowed to vary with daily SMAP-like inundation estimates. We show how the impacts of inundation inputs on model CH4 emission vary regionally, seasonally, and year-to-year. We also assess the relative impact on atmospheric CH4 concentration using atmospheric transport results from the Weather Research and Forecasting/Stochastic Time-Inverted Lagrangian Transport (WRF/STILT) Lagrangian particle dispersion model.

Galantowicz, J. F.; Wei, L. H.; Samanta, A.; Picton, J.; Zhang, B.; Lu, C.; Yang, J.; Tian, H.; Eluszkiewicz, J.; Nehrkorn, T.; Mountain, M.

2013-12-01

286

The Impact of the Gas Distribution on the Determination of Dynamical Masses of Galaxies Using Unresolved Observations  

NASA Astrophysics Data System (ADS)

Dynamical mass (M dyn) is a key property of any galaxy, yet a determination of M dyn is not straightforward if spatially resolved measurements are not available. This situation occurs in single-dish H I observations of the local universe, but also frequently in high-redshift observations. M dyn measurements in high-redshift galaxies are commonly obtained through observations of the CO line, the most abundant tracer of the molecular medium. Even though in most cases the CO line width can be determined with reasonable accuracy, a measurement of the size of the emitting region is typically challenging given current facilities. We show how the integrated spectra ("global profiles") of a variety of galaxy models depend on the spatial distribution of the tracer gas as well as its velocity dispersion. We demonstrate that the choice of tracer emission line (e.g., H I tracing extended, "flat," emission versus CO tracing more compact, "exponential," emission) significantly affects the shape of the global profiles. In particular, in the case of high (~50 km s-1) velocity dispersions, compact tracers (such as CO) result in Gaussian-like (non-double-horned) profiles, as is indeed frequently seen in high-redshift observations. This leads to significantly different determinations of M dyn if different distributions of the tracer material ("flat" versus "exponential") are considered. We determine at which radii the rotation curve reaches the rotation velocity corresponding to the velocity width, and find that for each tracer this happens at a well-defined radius: H I velocity widths typically originate at ~5 optical scale lengths, while CO velocity widths trace the rotation velocity at ~2 scale lengths. We additionally explore other distributions to take into account that CO distributions at high redshift likely differ from those at low redshift. Our models, while not trying to reproduce individual galaxies, define characteristic radii that can be used in conjunction with the measured velocity widths in order to define dynamical masses consistent with the assumed gas distribution.

de Blok, W. J. G.; Walter, Fabian

2014-05-01

287

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

288

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

289

Comparison of the limulus amebocyte lysate test and gas chromatography-mass spectrometry for measuring lipopolysaccharides (endotoxins) in airborne dust from poultry-processing industries.  

PubMed Central

The lipopolysaccharide (endotoxin) content in airborne dust samples from three different poultry slaughterhouses was determined with both the chromogenic Limulus amebocyte lysate assay and gas chromatography-mass spectrometry analysis of lipopolysaccharide-derived 3-hydroxy fatty acids. Gram-negative cell walls were also measured by using two-dimensional gas chromatography/electron-capture analysis of diaminopimelic acid originating from the peptidoglycan. The correlation between the results of the Limulus assay and those of gas chromatography-mass spectrometry for determination of the lipopolysaccharide content in the dust samples was poor, whereas a good correlation was obtained between lipopolysaccharide and diaminopimelic acid concentrations with the gas chromatographic methods. The results suggest that it is predominantly cell-wall-dissociated lipopolysaccharides that are measured with the Limulus assay, whereas the gas chromatographic methods allow determination of total concentrations of lipopolysaccharide, including Limulus-inactive lipopolysaccharide, gram-negative cells, and cellular debris. PMID:2187411

Sonesson, A; Larsson, L; Schütz, A; Hagmar, L; Hallberg, T

1990-01-01

290

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

291

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

292

Environmental impacts of the expected increase in sea transportation, with a particular focus on oil and gas scenarios for Norway and northwest Russia  

NASA Astrophysics Data System (ADS)

We have complemented existing global sea transportation emission inventories with new regional emission data sets and scenarios for ship traffic and coastal activity in 2015. Emission inventories for 2000 and 2015 are used in a global Chemical Transport Model (CTM) to quantify environmental atmospheric impacts with particular focus on the Arctic region. Although we assume that ship emissions continue to increase from 2000 to 2015, reductions are assumed for some chemical components and regions because of implementation of new regulations. Current ship traffic (2000) is estimated to contribute significantly to coastal pollution. Norwegian coastal ship traffic is responsible for more than 1/3 and 1/6 of the Norwegian NOx and SO2 emissions, respectively. For these short-lived components the impact of Norwegian coastal emissions is regionally important. For most components the international ship transportation outside coastal waters dominates the effects. Ship emissions increase wet deposition in Scandinavia with 30-50% for nitrate and 10-25% for sulfate. In general, coastal regions with prevailing onshore winds show substantial increases in deposition of acid components. Maximum surface increase in ozone is in excess of 10 ppbv. Column ozone increases are also significant. Assuming no changes in nonshipping emissions, scenarios for shipping activities in 2015 lead to more than 20% increase in NO2 from 2000 to 2015 in some coastal areas. Ozone increases are in general small. Wet deposition of acidic species increases up to 10% in areas where current critical loads are exceeded. Regulations limiting the sulfur content in the fuel in the North Sea and English Channel will be an efficient measure to reduce sulfate deposition in nearby coastal regions. The expected oil and gas transport by ships from Norway and northwest Russia, sea transport along the Northern Sea Route and new Norwegian coastal gas power plants will have a significant regional effect by increases of acid deposition in north Scandinavia and the Kola Peninsula. Augmented levels of particles in the Arctic are calculated, and thus the contribution from ship traffic to phenomena like Arctic haze could be increasing.

Dalsøren, Stig B.; Endresen, Øyvind; Isaksen, Ivar S. A.; Gravir, Gjermund; Sørgârd, Eirik

2007-01-01

293

Effect of farming practices for greenhouse gas mitigation and subsequent alternative land use on environmental impacts of beef cattle production systems.  

PubMed

This study evaluated effects of farming practice scenarios aiming to reduce greenhouse gas (GHG) emissions and subsequent alternative land use on environmental impacts of a beef cattle production system using the life cycle assessment approach. The baseline scenario includes a standard cow-calf herd with finishing heifers based on grazing, and a standard bull-fattening herd using a diet mainly based on maize silage, corresponding to current farm characteristics and management by beef farmers in France. Alternative scenarios were developed with changes in farming practices. Some scenarios modified grassland management (S1: decreasing mineral N fertiliser on permanent grassland; S2: decreasing grass losses during grazing) or herd management (S3: underfeeding of heifers in winter; S4: fattening female calves instead of being reared at a moderate growth rate; S5: increasing longevity of cows from 7 to 9 years; S6: advancing first calving age from 3 to 2 years). Other scenarios replaced protein sources (S7: partially replacing a protein supplement by lucerne hay for the cow-calf herd; S8: replacing soya bean meal with rapeseed meal for the fattening herd) or increased n-3 fatty acid content using extruded linseed (S9). The combination of compatible scenarios S1, S2, S5, S6 and S8 was also studied (S10). The impacts, such as climate change (CC, not including CO2 emissions/sequestration of land use and land-use change, LULUC), CC/LULUC (including CO2 emissions of LULUC), cumulative energy demand, eutrophication (EP), acidification and land occupation (LO) were expressed per kg of carcass mass and per ha of land occupied. Compared with the baseline, the most promising practice to reduce impacts per kg carcass mass was S10 (all reduced by 13% to 28%), followed by S6 (by 8% to 10%). For other scenarios, impact reduction did not exceed 5%, except for EP (up to 11%) and LO (up to 10%). Effects of changes in farming practices (the scenarios) on environmental impacts varied according to impact category and functional unit. For some scenarios (S2, S4, S6 and S10), permanent grassland area and LO per kg of carcass decreased by 12% to 23% and 9% to 19%, respectively. If the 'excess' permanent grassland was converted to fast-growing conifer forest to sequester carbon in tree and soil biomass, CC/LULUC per kg of carcass could be reduced by 20%, 25%, 27% and 48% for scenarios S2, S4, S6 and S10, respectively. These results illustrate the potential of farming practices and forest as an alternative land use to contribute to short- and mid-term GHG mitigation of beef cattle production systems. PMID:23190866

Nguyen, T T H; Doreau, M; Eugène, M; Corson, M S; Garcia-Launay, F; Chesneau, G; van der Werf, H M G

2013-05-01

294

Gas Pressure  

NSDL National Science Digital Library

This radio broadcast discusses the boom in natural gas drilling in the Rocky Mountain region and is possible impacts on the environment. A resource advocate points out the issue of well density, which can range from four wells per square mile to sixteen, 32, or more, and results in fragmentation of habitat as well as an ugly industrial appearance. The clip is 2 minutes in length and is available in MP3 format.

Pomplun, Steve

2012-08-06

295

Isolation and characterization of hydrogen-oxidizing bacteria induced following exposure of soil to hydrogen gas and their impact on plant growth.  

PubMed

In many legumes, the nitrogen fixing root nodules produce H2 gas that diffuses into soil. It has been demonstrated that such exposure of soil to H2 can promote plant growth. To assess whether this may be due to H2-oxidizing microorganisms, bacteria were isolated from soil treated with H2 under laboratory conditions and from soils collected adjacent to H2 producing soybean nodules. Nineteen isolates of H2-oxidizing bacteria were obtained and all exhibited a half-saturation coefficient (Ks) for H2 of about 1 ml l(-1). The isolates were identified as Variovorax paradoxus, Flavobacterium johnsoniae and Burkholderia spp. using conventional microbiological tests and 16S rRNA gene sequence analysis. Seventeen of the isolates enhanced (57-254%) root elongation of spring wheat seedlings. Using an Arabidopsis thaliana bioassay, plant biomass was increased by 11-27% when inoculated by one of four isolates of V. paradoxus or one isolate of Burkholderia that were selected for evaluation. The isolates of V. paradoxus found in both H2-treated soil and in soil adjacent to soybean nodules had the greatest impact on plant growth. The results are consistent with the hypothesis that H2-oxidizing bacteria in soils have plant growth promoting properties. PMID:17222141

Maimaiti, Jiamila; Zhang, Ye; Yang, Jing; Cen, Yan-Ping; Layzell, David B; Peoples, Mark; Dong, Zhongmin

2007-02-01

296

Development and validation of compressible mixture viscous fluid algorithm applied to predict the evolution of inertial fusion energy chamber gas and the impact of gas on direct-drive target survival  

E-print Network

upon temperature and pressure gradients within the gas. V isgases diffuse relative to each other due to temperature and pressure gradients.gas conductively cools much more rapidly for the same temperature gradient.

Martin, Robert Scott

2011-01-01

297

Compact ultrafast orthogonal acceleration time-of-flight mass spectrometer for on-line gas analysis by electron impact ionization and soft single photon ionization using an electron beam pumped rare gas excimer lamp as VUV-light source.  

PubMed

Orthogonal acceleration time-of-flight mass spectrometers (oaTOFMS), which are exhibiting a pulsed orthogonal extraction of ion bunches into the TOF mass analyzer from a continuous primary ion beam, are well-suited for continuous ionization methods such as electron impact ionization (EI). Recently an electron beam pumped rare gas excimer lamp (EBEL) was introduced, which emits intensive vacuum UV (VUV) radiation at, e.g., 126 nm (argon excimer) and is well suited as the light source for soft single photon ionization (SPI) of organic molecules. In this paper, a new compact oaTOFMS system which allows switching between SPI, using VUV-light from an EBEL-light source, and conventional EI is described. With the oaTOFMS system, EBEL-SPI and EI mass spectral transients can be recorded at very high repetition rates (up to 100 kHz), enabling high duty cycles and therefore good detection efficiencies. By using a transient recorder card with the capability to perform on-board accumulation of the oaTOF transients, final mass spectra with a dynamic range of 106 can be saved to the hard disk at a rate of 10 Hz. As it is possible to change the ionization modes (EI and SPI) rapidly, a comprehensive monitoring of complex gases with highly dynamic compositions, such as cigarette smoke, is possible. In this context, the EI based mass spectra address the bulk composition (compounds such as water, oxygen, carbon dioxide, etc. in the up to percentage concentration range) as well as some inorganic trace gases such as argon, sulfur dioxide, etc. down to the low ppm level. The EBEL-SPI mass spectra on the other hand are revealing the organic composition down to the lower ppb concentration range. PMID:17900147

Mühlberger, F; Saraji-Bozorgzad, M; Gonin, M; Fuhrer, K; Zimmermann, R

2007-11-01

298

SPECIAL ISSUE DEVOTED TO THE 25th ANNIVERSARY OF THE A.M. PROKHOROV GENERAL PHYSICS INSTITUTE: Generation of laser-pulse-field harmonics in a gas upon impact ionisation of atoms  

NASA Astrophysics Data System (ADS)

The generation of harmonics of a high-power-laser-pulse field in a gas during impact ionisation of atoms by oscillating electrons is studied theoretically. Fields are considered under conditions when the oscillation energy of electrons in the radiation field, remaining nonrelativistic, considerably exceeds the ionisation potential of an atom. In addition, the radiation field was assumed weak compared to the atomic field (Ea = 5.1×109 V cm-1), which allowed us to neglect the field ionisation of atoms, taking into account only the impact ionisation of atoms by oscillating electrons. Under such conditions, along with the elastic scattering of electrons, the inelastic scattering of oscillating electrons accompanied by ionisation of gas atoms can make a significant contribution to a nonlinear current induced in the plasma.

Kuzelev, M. V.; Rukhadze, A. A.

2007-10-01

299

Correlation of radioactive waste treatment costs and the environmental impact of waste effluents in the nuclear fuel cycle: reprocessing of high-temperature gas-cooled reactor fuel containing U-233 and thorium  

Microsoft Academic Search

A cost\\/benefit study was made to determine the cost and effectiveness of various radioactive waste (radwaste) treatment systems for decreasing the release of radioactive materials from a model high-temperature gas-cooled reactor (HTGR) fuel reprocessing plant and to determine the radiological impact (dose commitment) of the released materials on the environment. The study is designed to assist the U. S. Nuclear

W. Jr. Davis; R. E. Blanco; B. C. Finney; G. S. Hill; R. E. Moore; J. P. Witherspoon

2011-01-01

300

Correlation of radioactive waste treatment costs and the environmental impact of waste effluents in the nuclear fuel cycle: fabrication of high-temperature gas-cooled reactor fuel containing uranium-233 and thorium  

Microsoft Academic Search

A cost\\/benefit study was made to determine the cost and effectiveness of various radioactive waste (radwaste) treatment systems for decreasing the release of radioactive materials from model High-Temperature Gas-Cooled (HTGR) fuel fabrication plants and to determine the radiological impact (dose commitment) of the released materials on the environment. The study is designed to assist in defining the term ''as low

J. W. Roddy; R. E. Blanco; G. S. Hill; R. E. Moore; R. D. Seagren; J. P. Witherspoon

1976-01-01

301

Assessment of Anthropogenic Impact on Marine Ecosystems and Biological Resources in the Process of Oil and Gas Field Development in the Shelf Area  

Microsoft Academic Search

Current methodology of environmental impact assessment in connection with the environmental consequences of hydrocarbons production in the shelf area is analyzed. Basing on the ecosystem approach, a scheme of environmental impact estimates is suggested, envisaging the use of a set of gradations (scales) to characterize spatial and temporal scope of impacts and their consequences, as well as criteria (thresholds) of

S. A. Patin

2004-01-01

302

Outer Continental Shelf oil and gas information program. Outer Continental Shelf and onshore oil and gas activities and impacts in the Arctic: a summary report. Update 1, May 1982  

Microsoft Academic Search

This report was written to provide State and local officials in Alaska and other interested parties with current planning information about oil- and gas-related activities on the North Slope. Although only one exploratory well has been drilled on the Arctic OCS, the area has a long history of oil- and gas-related activities. The State has leased land on the North

J. B. Jackson; B. C. Pretz

1982-01-01

303

Guide to new natural gas utilization technologies  

Microsoft Academic Search

The natural gas industry in the United States is undergoing a fundamental transition as the wellhead price is decontrolled. The phased decontrol of new gas under the Natural Gas Policy Act of 1978 (NGPA) has had a dramatic positive impact on the natural gas supply picture. For the first time in 15 years the U.S. gas industry - which accounts

Hay

1985-01-01

304

3-D agricultural air quality modeling: Impacts of NH3/H2S gas-phase reactions and bi-directional exchange of NH3  

NASA Astrophysics Data System (ADS)

Accurately simulating the transport and fate of reduced nitrogen (NHx = ammonia (NH3) + ammonium (NH4+))- and sulfur-containing compounds emitted from agricultural activities represents a major challenge in agricultural air quality modeling. In this study, the Community Multiscale Air Quality (CMAQ) modeling system is further developed and improved by implementing 22 ammonia (NH3)/hydrogen sulfide (H2S) related gas-phase reactions and adjusting a few key parameters (e.g., emission potential) for bi-directional exchange of NH3 fluxes. Several simulations are conducted over the eastern U.S. domain at a 12-km horizontal resolution for January and July 2002 to examine the impacts of those improved treatments on air quality. The 5th generation mesoscale model (MM5) and CMAQ predict an overall satisfactory and consistent performance with previous modeling studies, especially for 2-m temperature, 2-m relative humidity, ozone (O3), and fine particulate matter (PM2.5). High model biases exist for precipitation in July and also dry/wet depositions. The updated model treatments contribute to O3, NHx, and PM2.5 by up to 0.4 ppb, 1.0 ?g m-3, and 1.0 ?g m-3 in January, respectively, and reduce O3 by up to 0.8 ppb and contribute to NHx and PM2.5 by up to 1.2 and 1.1 ?g m-3 in July, respectively. The spatial distributions of O3 in both months and sulfur dioxide (SO2) in January are mainly affected by inline dry deposition velocity calculation. The spatial distributions of SO2 and sulfate (SO42-) in July are affected by both inline dry deposition velocity and NH3/H2S reactions. The variation trends of NH3, NHx, ammonium nitrate (NH4NO3), PM2.5 and total nitrogen (TN) are predominated by bi-directional exchange of NH3 fluxes. Uncertainties of NH3 emission potentials and empirical constants used in the bi-directional exchange scheme may significantly affect the concentrations of NHx and PM2.5, indicating that a more accurate and explicit treatment for those parameters should be considered in the future work.

Wang, Kai; Zhang, Yang

2014-12-01

305

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

306

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

307

The impact of carbon dioxide and exhaust gas recirculation on the oxidative reactivity of soot from ethylene flames and diesel engines  

NASA Astrophysics Data System (ADS)

Restrictive emissions standards to reduce nitrogen oxides (NOx) and particulate matter (PM) emissions from diesel engines necessitate the development of advanced emission control technology. The engine manufacturers in the United States have implemented the exhaust gas recirculation (EGR) and diesel particulate filters (DPF) to meet the stringent emissions limits on NOx and PM, respectively. Although the EGR-DPF system is an effective means to control diesel engine emissions, there are some concerns associated with its implementation. The chief concern with this system is the DPF regenerability, which depends upon several factors, among which are the physicochemical properties of the soot. Despite the plethora of research that has been conducted on DPF regenerability, the impact of EGR on soot reactivity and DPF regenerability is yet to be examined. This work concerns the impact of EGR on the oxidative reactivity of diesel soot. It is part of ongoing research to bridge the gap in establishing a relationship between soot formation conditions, properties, and reactivity. This work is divided into three phases. In the first phase, carbon dioxide (CO2) was added to the intake charge of a single cylinder engine via cylinders of compressed CO2. This approach simulates the cold-particle-free EGR. The results showed that inclusion of CO2 changes the soot properties and yields synergistic effects on the oxidative reactivity of the resulting soot. The second phase of this research was motivated by the findings from the first phase. In this phase, post-flame ethylene soot was produced from a laboratory co-flow laminar diffusion flame to better understand the mechanism by which the CO2 affects soot reactivity. This phase was accomplished by successfully isolating the dilution, thermal, and chemical effects of the CO2. The results showed that all of these effects account for a measurable increase in soot reactivity. Nevertheless, the thermal effect was found to be the most important factor governing the soot reactivity. In the third phase of this research, diesel soot was generated under 0 and 20% EGR using a four-cylinder, four-stroke, turbocharged common rail direct injection (DI) DDC diesel engine. The objective of this work was to examine the relevance of the single cylinder engine and flame studies to practical engine operation. The key engine parameters such as load, speed, and injection timing were kept constant to isolate the EGR effect on soot properties from any other engine effects. The thermokinetic analyses of the flame soot and engine soot showed a significant increase in soot oxidation rate as a result of the CO2 or EGR inclusion into the combustion process. The activation energy of soot oxidation was found to be independent of soot origin or formation history. The increase in soot oxidation rate is attributed solely to the increase in soot active sites, which are presented implicitly in the pre-exponential factor (A) of the oxidation rate equation. This latter statement was confirmed by measuring the initial active site area (ASA i) of all soot samples considered in this study. As expected, higher oxidation rates are associated with higher ASAi. The chemical properties of the soot were investigated to determine their effects upon soot reactivity. The results showed that the H/C and O/C ratios were not modified by CO2 or EGR addition. Therefore, these ratios are not reactivity parameters and their effects upon soot reactivity were ruled out. In distinct contrast, the physical properties of the soot were modified by the addition of CO2 or EGR. The interlayer spacing (d002) between the aromatic sheets increased, the crystallite width (La) decreased and the crystallite height (Lc) decreased as a consequence of CO 2 or EGR addition. The modified physical properties of the soot are responsible for the increased rate of soot oxidation. In order to examine the soot oxidation behavior in the DPF, the soot samples produced from the DDC engine under 0 and 20% EGR were partially oxidized in a thermogravimetric analyzer (TGA) to s

Al-Qurashi, Khalid O.

308

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

309

Determining marginal electricity for near-term plug-in and fuel cell vehicle demands in California: Impacts on vehicle greenhouse gas emissions  

Microsoft Academic Search

California has taken steps to reduce greenhouse gas emissions from the transportation sector. One example is the recent adoption of the Low Carbon Fuel Standard, which aims to reduce the carbon intensity of transportation fuels. To effectively implement this and similar policies, it is necessary to understand well-to-wheels emissions associated with distinct vehicle and fuel platforms, including those using electricity.

Ryan McCarthy; Christopher Yang

2010-01-01

310

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  

Microsoft Academic Search

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

Ehst

2006-01-01

311

Impacts of rumen fluid modified by feeding Yucca schidigera to lactating dairy cows on in vitro gas production of 11 common dairy feedstuffs, as well as animal performance  

Microsoft Academic Search

The objective was to determine effects of feeding increasing levels of a Yucca schidigera extract (YSE) to dairy cows on 24h in vitro gas production and 27h in vitro neutral detergent fibre (aNDFom) digestion of 11 common dairy feedstuffs, as well as in vivo rumen fermentation and performance of the cows to which the YSE was fed. The principle was

M. D. Singer; P. H. Robinson; A. Z. M. Salem; E. J. DePeters

2008-01-01

312

Impacts of future climate scenarios on the balance between productivity and total greenhouse gas emissions from pasture based dairy systems in south-eastern Australia  

Microsoft Academic Search

The challenge for agriculture is to increase production in warmer climates in order to meet the demands of an increasing global population, while also meeting targets for reduced greenhouse gas (GHG) emissions. Our aim was to quantify the net effect of future climate scenarios on the productivity and total GHG emissions from pasture based dairy systems in 4 regions of

B. R. Cullen; R. J. Eckard

2011-01-01

313

Ngfast : a simulation model for rapid assessment of impacts of natural gas pipeline breaks and flow reductions at U. S. state borders and import points.  

SciTech Connect

This paper describes NGfast, the new simulation and impact-analysis tool developed by Argonne National Laboratory for rapid, first-stage assessments of impacts of major pipeline breaks. The methodology, calculation logic, and main assumptions are discussed. The concepts presented are most useful to state and national energy agencies tasked as first responders to such emergencies. Within minutes of the occurrence of a break, NGfast can generate an HTML-formatted report to support briefing materials for state and federal emergency responders. Sample partial results of a simulation of a real system in the United States are presented.

Portante, E. C.; Craig, B. A.; Folga, S.M.

2007-01-01

314

Preservative properties of Calamintha officinalis essential oil with and without EDTA  

Microsoft Academic Search

Aims: This study was focused on the preserving properties of Calamintha officinalis essential oil, a plant known for its diaphoretic, expectorant and aromatic properties. Methods and Results: The commercial aerial parts of C. officinalis Moench were hydrodistilled and the essential oil analysed by Gas chromatography\\/Electron impact mass spectrometry (GC ? EIMS). The inhibition efficacy of this essence, alone (0Æ5 and

A. Nostro; M. A. Cannatelli; I. Morelli; P. L. Cioni; A. Bader; A. Marino; V. Alonzo

2002-01-01

315

Environmental impacts of the expected increase in sea transportation, with a particular focus on oil and gas scenarios for Norway and northwest Russia  

Microsoft Academic Search

We have complemented existing global sea transportation emission inventories with new regional emission data sets and scenarios for ship traffic and coastal activity in 2015. Emission inventories for 2000 and 2015 are used in a global Chemical Transport Model (CTM) to quantify environmental atmospheric impacts with particular focus on the Arctic region. Although we assume that ship emissions continue to

Stig B. Dalsøren; Øyvind Endresen; Ivar S. A. Isaksen; Gjermund Gravir; Eirik Sørgård

2007-01-01

316

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

317

Modelling impacts of alternative farming management practices on greenhouse gas emissions from a winter wheat–maize rotation system in China  

Microsoft Academic Search

Agricultural production plays an important role in affecting atmospheric greenhouse gas concentrations. Field measurements were conducted in Quzhou County, Hebei Province in the North China Plains to quantify carbon dioxide (CO2) and nitrous oxide (N2O) emissions from a winter wheat–maize rotation field, a common cropping system across the Chinese agricultural regions. The observed flux data in conjunction with the local

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

2010-01-01

318

Assessing the impact of forest fragmentation due to natural gas development on wild turkey nesting success in Van Buren County, Arkansas  

NASA Astrophysics Data System (ADS)

Natural gas exploration and production has caused large scale changes to portions of the Arkansas landscape. Well pad site construction, access roads, and pipelines utilized to extract and transport natural gas have fragmented forested areas. The forest fragmentation resulting from these rapid changes could be contributing to the documented decline in nesting success of the wild turkey (Meleagris gallopavo). This study quantified temporal changes in forest fragmentation in terms of the number of forest patches, mean forest patch area, and forest edge length. The correlation between these fragmentation variables and nesting success data was explored to test the hypotheses of this study that 1) the number of forest patches is negatively correlated to nesting success, that 2) forest patch size is positively correlated to nesting success, and that 3) forest edge habitat length is negatively correlated to nesting success. There were 838 wells added within Van Buren County during the years 2000 through 2009. These wells resulted in a total forest loss of about 1.5% area from the initial inventory of forest in 2000. Pearson product moment correlation (PPMC) values ranging from -0.19 to 0.17 suggests relationships exist between poults per hen and forest fragmentation due to natural gas development. These PPMC values and their respective directions confirm the hypothesis. However, their p-values were all greater than 0.5 which suggests the correlations may not be statistically significant. A stronger regression model, giving adjusted R squared value of 0.766, was constructed which takes into account annual precipitation, previous year's wild turkey harvest, along with the number of conifer forest patches. This study concludes that the low wild turkey nesting success may not be directly influenced by forests lost due to natural gas development within the study area Van Buren County Arkansas.

Casey, James Kendall

319

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

320

Reactive mass transfer at gas–liquid interfaces: impact of micro-scale fluid dynamics on yield and selectivity of liquid-phase cyclohexane oxidation  

Microsoft Academic Search

The impact of single-bubble wake dynamics on the reaction-enhanced mass transfer and on the yield and selectivity of the cyclohexane oxidation reaction was studied using a two-dimensional CFD-reaction model that was developed by our group. Temperature and the concentrations of the (desired) intermediate and (undesired) final products of this autocatalytic reaction were the parameters of this study. Two bubble types

Johannes G. Khinast; Athanas A. Koynov; Tiberiu M. Leib

2003-01-01

321

Impacts of Spatial Fidelity Violations in the Forward Signal Model on DOAS-based Greenhouse Gas Retrievals: a Preliminary Analysis for OCO-2 (and Other Missions)  

NASA Technical Reports Server (NTRS)

Success in three aspects of OCO-2 mission is threatened by unaccounted spa,al variability effects, all involving atmospheric scattering: 1. Low/moderately opaque clouds can escape the prescreening by mimicking a brighter surface. 2. Prescreening does not account for long-range radia,ve impact (adjacency effect) of nearby clouds. Need for extended cloud masking? 3. Oblique looks in target mode are highly exposed to surface adjacency and aerosol variability effects.We'll be covering all three bases!

Davis, Anthony B.; Frakenbert, Christian

2012-01-01

322

Soil radium, soil gas radon and indoor radon empirical relationships to assist in post-closure impact assessment related to near-surface radioactive waste disposal.  

PubMed

Least squares (LS), Theil's (TS) and weighted total least squares (WTLS) regression analysis methods are used to develop empirical relationships between radium in the ground, radon in soil and radon in dwellings to assist in the post-closure assessment of indoor radon related to near-surface radioactive waste disposal at the Low Level Waste Repository in England. The data sets used are (i) estimated ²²?Ra in the < 2 mm fraction of topsoils (eRa226) derived from equivalent uranium (eU) from airborne gamma spectrometry data, (ii) eRa226 derived from measurements of uranium in soil geochemical samples, (iii) soil gas radon and (iv) indoor radon data. For models comparing indoor radon and (i) eRa226 derived from airborne eU data and (ii) soil gas radon data, some of the geological groupings have significant slopes. For these groupings there is reasonable agreement in slope and intercept between the three regression analysis methods (LS, TS and WTLS). Relationships between radon in dwellings and radium in the ground or radon in soil differ depending on the characteristics of the underlying geological units, with more permeable units having steeper slopes and higher indoor radon concentrations for a given radium or soil gas radon concentration in the ground. The regression models comparing indoor radon with soil gas radon have intercepts close to 5 Bq m?³ whilst the intercepts for those comparing indoor radon with eRa226 from airborne eU vary from about 20 Bq m?³ for a moderately permeable geological unit to about 40 Bq m?³ for highly permeable limestone, implying unrealistically high contributions to indoor radon from sources other than the ground. An intercept value of 5 Bq m?³ is assumed as an appropriate mean value for the UK for sources of indoor radon other than radon from the ground, based on examination of UK data. Comparison with published data used to derive an average indoor radon: soil ²²?Ra ratio shows that whereas the published data are generally clustered with no obvious correlation, the data from this study have substantially different relationships depending largely on the permeability of the underlying geology. Models for the relatively impermeable geological units plot parallel to the average indoor radon: soil ²²?Ra model but with lower indoor radon: soil ²²?Ra ratios, whilst the models for the permeable geological units plot parallel to the average indoor radon: soil ²²?Ra model but with higher than average indoor radon: soil ²²?Ra ratios. PMID:20951477

Appleton, J D; Cave, M R; Miles, J C H; Sumerling, T J

2011-03-01

323

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

324

Hydrogeology of a coal-seam gas exploration area, southeastern British Columbia, Canada: Part 2. Modeling potential hydrogeological impacts associated with depressurizing  

NASA Astrophysics Data System (ADS)

A three-dimensional, finite-element flow model was used to assess the hydrogeological effects of depressurizing coalbeds lying in the Weary Creek exploration block, Elk River valley, southeastern British Columbia, Canada. The simulation results permit, at an early stage, assessment of the environmental and economic implications of how the flow system may respond to depressurization. Estimated reservoir conditions for the coal-seam gas targets lying within the Upper Jurassic-Lower Cretaceous Mist Mountain Formation indicate that the coalbeds must be depressurized by up to 350 m to attain the critical gas desorption pressure. The simulations suggest that depressurizing has little effect on groundwater flux to the Elk River. Simulated water production for three depressurizing wells operating under steady-state, single-phase flow for initial reservoir conditions of 13 and 16.5 cm3/g is 645 m3/d (4,057 barrels/d) and 355 m3/d (2,233 barrels/d), respectively. Groundwaters collected from monitoring wells have relatively low salinity, ranging from about 250-1,300 mg/L. The groundwater is supersaturated with respect to Ca-Mg-Fe carbonates (calcite, dolomite, and siderite) and Al-bearing silicates, including kaolinite and illite. Dissolved trace-metal concentrations are low; only Fe, Cd, Cr, and Zn exceed Canadian water-quality guidelines for aquatic life. Groundwaters were devoid of the more soluble monocyclic aromatic organic compounds, including benzene, toluene, ethylbenzene, and polycyclic aromatic compounds, including naphthalene.

Harrison, S.; Molson, J.; Abercrombie, H.; Barker, J.

2000-12-01

325

Gas chromatographic-mass spectrometric separation and identification of combustion products of organo-phosphorus and chlorine pesticides and evaluation of their impact on the environment.  

PubMed

A simple and rapid GC-MS method for separation, identification and quantitative determination of combustion products of organophosphorus and chlorine pesticides viz; monocrotophos, chloropyriphos, butachlor and benzenehexachloride has been developed. The method provides a positive means of identifying organic combustion products and enables to assess not only their toxicity to human beings but also their impact on the environment. The data is useful for emergency preparations in case of fire in chemical plants and warehouses that store pesticides in large quantities. PMID:12058907

Rao, R Nageswara; Khalid, Sara; Rajani, T; Husain, S

2002-04-19

326

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

327

Application of landfill gas as a liquefied natural gas fuel for refuse trucks in Texas  

E-print Network

apparent negative impacts of these conventional fuels are global warming, poor air-quality, and adverse health effects. Considering these negative impacts, it is necessary to develop and use non-conventional sources of energy. Landfill gas (LFG) generated...

Gokhale, Bhushan

2007-04-25

328

Acid-catalyzed condensed-phase reactions of limonene and terpineol and their impacts on gas-to-particle partitioning in the formation of organic aerosols.  

PubMed

We investigated the condensed-phase reactions of biogenic VOCs with C double bond C bonds (limonene, C(10)H(16), and terpineol, C(10)H(18)O) catalyzed by sulfuric acid by both bulk solution (BS) experiments and gas-particle (GP) experiments using a flow cell reactor. Product analysis by gas chromatography-mass spectrometry (GC-MS) showed that cationic polymerization led to dimeric and trimeric product formation under conditions of relative humidity (RH) <20% (in the GP experiments) and a sulfuric acid concentration of 57.8 wt % (in the BS experiments), while hydration occurred under conditions of RH > 20% (in the GP experiments) and sulfuric acid concentrations of 46.3 wt % or lower (in the BS experiments). Apparent partitioning coefficients (K(p,rxn)) were estimated from the GP experiments by including the reaction products. Only under extremely low RH conditions (RH < 5%) did the values of K(p,rxn) ( approximately 5 x 10(-6) m(3)/microg for limonene and approximately 2 x 10(-5) m(3)/microg for terpineol) substantially exceed the physical partitioning coefficients (K(p) = 6.5 x 10(-8) m(3)/microg for limonene and =2.3 x 10(-6) m(3)/microg for terpineol) derived from the absorptive partitioning theory. At RH higher than 5%, the apparent partitioning coefficients (K(p,rxn)) of both limonene and terpineol were in the same order of magnitude as the K(p) values derived from the absorptive partitioning theory. Compared with other conditions including VOC concentration and degree of neutralization (by ammonium) of acidic particles, RH is a critical parameter that influences both the reaction mechanisms and the uptake ability (K(p,rxn) values) of these processes. The finding suggests that RH needs to be considered when taking the effects of acid-catalyzed reactions into account in estimating organic aerosol formation from C double bond C containing VOCs. PMID:20550185

Li, Yong Jie; Cheong, Gema Y L; Lau, Arthur P S; Chan, Chak K

2010-07-15

329

Impact of historical land-use changes on greenhouse gas exchange in the U.S. Great Plains, 1883-2003.  

PubMed

European settlement of North America has involved monumental environmental change. From the late 19th century to the present, agricultural practices in the Great Plains of the United States have dramatically reduced soil organic carbon (C) levels and increased greenhouse gas (GHG) fluxes in this region. This paper details the development of an innovative method to assess these processes. Detailed land-use data sets that specify complete agricultural histories for 21 representative Great Plains counties reflect historical changes in agricultural practices and drive the biogeochemical model, DAYCENT, to simulate 120 years of cropping and related ecosystem consequences. Model outputs include yields of all major crops, soil and system C levels, soil trace-gas fluxes (N2O emissions and CH4 consumption), and soil nitrogen mineralization rates. Comparisons between simulated and observed yields allowed us to adjust and refine model inputs, and then to verify and validate the results. These verification and validation exercises produced measures of model fit that indicated the appropriateness of this approach for estimating historical changes in crop yield. Initial cultivation of native grass and continued farming produced a significant loss of soil C over decades, and declining soil fertility led to reduced crop yields. This process was accompanied by a large GHG release, which subsided as soil fertility decreased. Later, irrigation, nitrogen-fertilizer application, and reduced cultivation intensity restored soil fertility and increased crop yields, but led to increased N2O emissions that reversed the decline in net GHG release. By drawing on both historical evidence of land-use change and scientific models that estimate the environmental consequences of those changes, this paper offers an improved way to understand the short- and long-term ecosystem effects of 120 years of cropping in the Great Plains. PMID:21774417

Hartman, Melannie D; Merchant, Emily R; Parton, William J; Gutmann, Myron P; Lutz, Susan M; Williams, Stephen A

2011-06-01

330

Impact of operating parameters changing on energy, environment and economic efficiencies of a lean burn gas engine used in a cogeneration plant  

SciTech Connect

The facts that national electrical company Electricite de France (EDF) has a monopoly on electrical power production in France and an extensive installed base of nuclear power plants, explain the difficulty encountered in developing cogeneration technology in France. Cogeneration only really first appeared in this country in the early 1990's, with the liberalization of energy markets and the government's encouragement. Since then, the number of cogeneration plants has continuously increased and electrical generating capacity is now approximately 1,200 MWe. Turbine and reciprocating engines (most of which are natural gas fired) account respectively for about 55% and 45% of the installed power. Unlike other countries, such as Germany--which has about two thousand 500 kWe and smaller units--the future of low-power cogeneration in France is far from assured, and there are currently less than 10 such plants. To help develop this efficient technology for producing electrical power and hot water, the Ecole des Mines de Nantes purchased a 210 kWe cogeneration generator set in 1996. This facility provides all or part of the school's electrical and heat requirements during five months between November and March. This cogeneration facility is also used during the rest of the year to perform research experiments in the field of lean-burn natural gas combustion. Lastly, it is also used to provide training for industry in cogeneration technology. Within this context, work was undertaken to study the set's energy and emissions performance, in relation to such parameters as spark advance and air factor, and at various loads.

Lemoult, B.; Tazerout, M.; Rousseau, S.

1998-07-01

331

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

332

The impact of accounting methods on the association between unexpected earnings and abnormal returns: The case of oil and gas industry  

NASA Astrophysics Data System (ADS)

Full cost (FC) and successful efforts (SE) are two competing accounting methods that account for exploration and development expenditures in oil and gas industry. In 1977, the Financial Accounting Standards Board (FASB) abolished the FC method but the abolishment was overruled by the Securities and Exchange Commission (SEC) in 1978. Many studies have addressed the issue and focused on the market reaction to the uncertain status of the standard rather than on the information content of earnings. This study examines the extent to which the differences in variability of stock price responses to earnings announcements are associated with the FC and SE accounting methods. The purpose of this study is to investigate whether the market reacts differently to the release of earnings by FC and SE firms. The study contributes to the current literature by comparing the earnings response coefficient (ERC) of FC and SE firms and providing an alternative model to measure unexpected earnings. The study examines cross-sectional differences in ERCs associated with firm-characteristics (such as accounting method and size) and compare the results with firm-specific differences in ERCs which have not been used in previous oil and gas studies. The larger sample, the longer sample period, and the different source of data position this study as a triangulation to previous ERC studies. The study finds that pooled cross-sectional estimation results support previous findings that ERCs for SE firms are significantly higher than those for FC firms especially for return intervals before (including) the earnings release date. However, ERCs for FC firms tend to be larger than those for SE firms when firm-specific estimations are performed. For return intervals immediately following the announcement date, the firm-specific ERCs for FC firms are significantly higher than those of SE firms. This study also finds that the unexpected earnings variances are not homogeneous across firms and the firm-specific time-series variances vary more for FC firms than for SE firms resulting in more downward-biased ERCs for FC firms. Given that firm-specific estimations are more appropriate, the general conclusion is that ERCs for FC firms are higher than (or at least the same as) the ERCs for SE firms.

Suwardjono

333

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

334

Impact broadening, shifting, and asymmetry of the D1 and D2 lines of alkali-metal atoms colliding with noble-gas atoms  

NASA Astrophysics Data System (ADS)

The Anderson Talman theory of spectral line broadening is used together with potential energy curves calculated at the spin-orbit multi-reference configuration interaction level to compute broadening, shifting, and asymmetry coefficients of the D1 and D2 lines of alkali-metal atoms M, as they collide with noble gas atoms N, where M =K, Rb, and Cs, and N =He, Ne, and Ar. Our calculated coefficients are compared to experimental results for a variety of temperatures. In all cases general agreement is observed for the broadening coefficients, while significant disagreement is observed for the shifting coefficients. We also compare our K +He broadening and shifting results with fully quantum-mechanical calculations that employ the Baranger theory of collisional line broadening, and we compare our results with other semiclassical calculations. As with the comparison to experiment, closer agreement is observed for the broadening coefficients while the shifting coefficients exhibit significant disagreement. We use the natural variation between the difference potentials of the nine M +N pairs to explore the relationship between potential and line shape as determined by Anderson-Talman theory and develop a picture for the mechanism that underlies the general agreement between theoretical and experimental results on the broadening coefficient and the general disagreement on shifting coefficients.

Blank, L.; Weeks, David E.

2014-08-01

335

Heat-Capacity Lag in Gas Dynamics  

Microsoft Academic Search

The existence of energy dissipations in gas dynamics, which must be attributed to a lag in the vibrational heat capacity of the gas, has been established both theoretically and experimentally. The flow about a very small impact tube is discussed. It is shown that total-head defects due to heat-capacity lag during and after the compression of the gas at the

Arthur Kantrowitz

1946-01-01

336

Impact of urbanization on hydrochemical evolution of groundwater and on unsaturated-zone gas composition in the coastal city of Tel Aviv, Israel  

NASA Astrophysics Data System (ADS)

The coastal city of Tel Aviv was founded at the beginning of the 20th century. The number of its inhabitants and its water consumption increased rapidly. This study analyses a 15-year record (1934-1948) of pre-industrial development of groundwater chemistry in the urban area. Archive data on concentrations of major ions, dissolved gases (CO 2 and O 2), organic matter, and pH were available for each half-year during the period of 1934-1948. The major factors causing changes in the chemistry of groundwater flowing in three sandy sub-aquifers have been seawater encroachment due to overpumping, and infiltration of effluents from pit-latrine collectors. Influence of these factors decreases with depth. Landward-penetrating seawater passed through clayey coastal sediments, interbedded among sands and calcareous sandstones, and spread into the Kurkar Group aquifer. This has led to exchange of sodium (dominant in seawater) with calcium adsorbed on clay particles, enriching groundwater with calcium. Intensity of cation exchange decreases inland and with depth. Infiltration of pit-latrine effluents has introduced large amounts of ammonium into the unsaturated zone. Its rapid oxidation in unsaturated sediments has caused massive nitrate production, accompanied by pore-water acidification. This process induces dissolution of vadose carbonate, resulting in enrichment of groundwater recharge in calcium. Anthropogenically induced dissolution of calcite in the unsaturated zone has been the major factor for the increase of Ca 2+ concentration in groundwater, accounting for about 80% of this increase. In the interface zone, an additional 20% of calcium has been supplied by cation exchange. Owing to pH increase caused by denitrification in the aquifer, Ca 2+-rich waters supersaturated with calcite could be formed, especially in the capillary fringe of the uppermost sub-aquifer, which could induce calcite precipitation and ultimately lead to the cementation of sandy aquifers. Urban development has caused drastic changes in the gas content in the unsaturated zone and in groundwater. Carbon dioxide was intensively generated by nitrification-denitrification processes, by hydration of urea, to a lesser degree by oxidation of organic matter, and probably by anoxic biodegradation of organics. Between 1934 and 1948, concentrations of CO 2 in unsaturated sediment air rose from 3.2% to 7.6%. In the unsaturated zone, oxygen consumption for oxidation of ammonium and organic matter lowered O 2 concentrations in sediment air to unusually low values of 3.9-12.9%. Nitrification in the urban unsaturated zone could thus serve as a pump, sucking in atmospheric oxygen at a rate of about 0.3-0.5 g m -2 day -1. The extreme concentrations of CO 2 and O 2 in unsaturated sediments have been preserved due to production and consumption of gas under conditions of diminishing areas open to the atmosphere, uncovered by buildings and by roads.

Zilberbrand, M.; Rosenthal, E.; Shachnai, E.

2001-08-01

337

Impact of a reduced red and processed meat dietary pattern on disease risks and greenhouse gas emissions in the UK: a modelling study  

PubMed Central

Objectives Consumption of red and processed meat (RPM) is a leading contributor to greenhouse gas (GHG) emissions, and high intakes of these foods increase the risks of several leading chronic diseases. The aim of this study was to use newly derived estimates of habitual meat intakes in UK adults to assess potential co-benefits to health and the environment from reduced RPM consumption. Design Modelling study using dietary intake data from the National Diet and Nutrition Survey of British Adults. Setting British general population. Methods Respondents were divided into fifths by energy-adjusted RPM intakes, with vegetarians constituting a sixth stratum. GHG emitted in supplying the diets of each stratum was estimated using data from life-cycle analyses. A feasible counterfactual UK population was specified, in which the proportion of vegetarians measured in the survey population doubled, and the remainder adopted the dietary pattern of the lowest fifth of RPM consumers. Outcome measures Reductions in risks of coronary heart disease, diabetes and colorectal cancer, and GHG emissions, under the counterfactual. Results Habitual RPM intakes were 2.5 times higher in the top compared with the bottom fifth of consumers. Under the counterfactual, statistically significant reductions in population aggregate risks ranged from 3.2% (95% CI 1.9 to 4.7) for diabetes in women to 12.2% (6.4 to 18.0) for colorectal cancer in men, with those moving from the highest to lowest consumption levels gaining about twice these averages. The expected reduction in GHG emissions was 0.45 tonnes CO2 equivalent/person/year, about 3% of the current total, giving a reduction across the UK population of 27.8 million tonnes/year. Conclusions Reduced consumption of RPM would bring multiple benefits to health and environment. PMID:22964113

Smith, James N; Powles, John W

2012-01-01

338

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

339

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

340

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

341

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.

Gollan, Arye Z. [Newton, MA

1990-12-25

342

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.

Gollan, Arye (Newton, MA)

1988-01-01

343

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

344

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

345

Gas Laws  

NSDL National Science Digital Library

In this activity, students study gas laws at a molecular level. They vary the volume of a container at constant temperature to see how pressure changes (Boyle's Law), change the temperature of a container at constant pressure to see how the volume changes with temperature (Charlesâs Law), and experiment with heating a gas in a closed container to discover how pressure changes with temperature (Gay Lussac's Law). They also discover the relationship between the number of gas molecules and gas volume (Avogadro's Law). Finally, students use their knowledge of gas laws to model a heated soda can collapsing as it is plunged into ice water.

Consortium, The C.

2011-12-11

346

Determination of greenhouse gas emission resulting from gas flaring activities in Nigeria  

Microsoft Academic Search

Greenhouse gas emission and its effect on the environment have gained the attention of researchers, environmentalists and policy makers in recent times. This is as a result of its devastating impact both on the climate and the environment. Records of natural gas produced and natural gas flared in Nigeria from 1999 to 2009 were collected and subjected to descriptive analysis

O. Anomohanran

2012-01-01

347

ECONOMIC IMPACT OF THE APPALACHIAN GATEWAY  

E-print Network

, natural gas demand is forecast to increase through 2035. The Marcellus shale play and the new natural gas ECONOMIC IMPACT OF THE APPALACHIAN GATEWAY PROJECT By Randall A. Childs transmission infrastructure in place to get the gas to the customers. The Appalachian Gateway Project

Mohaghegh, Shahab

348

Intraspinal gas.  

PubMed

Intraspinal gas can be observed in a number of pathological settings including degenerative disc disease, infection, tumor or trauma, and in patients who have undergone therapeutic and diagnostic procedures. The air can be epidural, intradural or intradiscal. Intraspinal gas is usually asymptomatic. We report intraspinal gas in three patients, one with cervical, one with thoracic, and one with lumber disc disease and spondylolisthesis. The investigations were all completed at the the same medical center and CT and MRI were done in each case. The gas was in the epidural space in all three patients. These cases provide further evidence that intraspinal gas may persist without causing symptoms, and that resultant symptoms can disappear spontaneously. MRI is not reliable for diagnosing intraspinal gas; CT is recommended. PMID:17430780

Konya, Deniz; Ozgen, Serdar; Sun, Ibrahim H; Pamir, Necmettin M

2007-06-01

349

Hyptis suaveolens and Hyptis spicigera (Lamiaceae) essential oils: qualitative analysis, contact toxicity and repellent activity against Sitophilus granarius (L.) (Coleoptera: Dryophthoridae)  

Microsoft Academic Search

Essential oils from Hyptis suaveolens (L.) Poiteau (Lamiaceae) and Hyptis spicigera Lamarck (Lamiaceae) were first analysed by gas chromatography and by gas chromatography\\/electron impact mass spectroscopy\\u000a and then evaluated for toxicity and repellent activity against Sitophilus granarius (L.) (Coleoptera: Dryophthoridae), one of the most serious worldwide stored grain pests. Fifty-six compounds have been identified\\u000a in the essential oil of H.

Barbara ContiAngelo CanalePier; Angelo Canale; Pier Luigi Cioni; Guido Flamini; Alessandro Rifici

2011-01-01

350

Gas Properties  

NSDL National Science Digital Library

Pump gas molecules to a box and see what happens as you change the volume, add or remove heat, change gravity, and more. Measure the temperature and pressure, and discover how the properties of the gas vary in relation to each other.

Simulations, Phet I.; Barbera, Jack; Dubson, Michael; Koch, Linda; Lemaster, Ron; Perkins, Kathy

2005-07-01

351

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

352

Economics of natural gas upgrading  

SciTech Connect

Natural gas could be an important alternative energy source in meeting some of the market demand presently met by liquid products from crude oil. This study was initiated to analyze three energy markets to determine if greater use could be made of natural gas or natural gas derived products and if those products could be provided on an economically competitive basis. The three markets targeted for possible increases in gas use were motor fuels, power generation, and the chemical feedstocks market. The economics of processes to convert natural gas to transportation fuels, chemical products, and power were analyzed. The economic analysis was accomplished by drawing on a variety of detailed economic studies, updating them and bringing the results to a common basis. The processes analyzed included production of methanol, MTBE, higher alcohols, gasoline, CNG, and LNG for the transportation market. Production and use of methanol and ammonia in the chemical feedstock market and use of natural gas for power generation were also assessed. Use of both high and low quality gas as a process feed stream was evaluated. The analysis also explored the impact of various gas price growth rates and process facility locations, including remote gas areas. In assessing the transportation fuels market the analysis examined production and use of both conventional and new alternative motor fuels.

Hackworth, J.H.; Koch, R.W.

1995-07-01

353

Underground natural gas storage reservoir management  

SciTech Connect

The objective of this study is to research technologies and methodologies that will reduce the costs associated with the operation and maintenance of underground natural gas storage. This effort will include a survey of public information to determine the amount of natural gas lost from underground storage fields, determine the causes of this lost gas, and develop strategies and remedial designs to reduce or stop the gas loss from selected fields. Phase I includes a detailed survey of US natural gas storage reservoirs to determine the actual amount of natural gas annually lost from underground storage fields. These reservoirs will be ranked, the resultant will include the amount of gas and revenue annually lost. The results will be analyzed in conjunction with the type (geologic) of storage reservoirs to determine the significance and impact of the gas loss. A report of the work accomplished will be prepared. The report will include: (1) a summary list by geologic type of US gas storage reservoirs and their annual underground gas storage losses in ft{sup 3}; (2) a rank by geologic classifications as to the amount of gas lost and the resultant lost revenue; and (3) show the level of significance and impact of the losses by geologic type. Concurrently, the amount of storage activity has increased in conjunction with the net increase of natural gas imports as shown on Figure No. 3. Storage is playing an ever increasing importance in supplying the domestic energy requirements.

Ortiz, I.; Anthony, R.

1995-06-01

354

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

355

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

356

Natural Gas  

NASA Astrophysics Data System (ADS)

Natural gas is a naturally occurring mixture of simple hydrocarbons and nonhydrocarbons that exists as a gas at ordinary pressures and temperatures. In the raw state, as produced from the earth, natural gas consists principally of methane (CH4) and ethane (C2H4), with fractional amounts of propane (C3H8), butane (C4H10), and other hydrocarbons, pentane (C5H12) and heavier. Occasionally, small traces of light aromatic hydrocarbons such as benzene and toluene may also be present.

Maddox, Robert N.; Moshfeghian, Mahmood; Ldol, James D.; Johannes, Arland H.

357

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

358

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

359

The Future of Electricity (and Gas) Regulation  

E-print Network

prices rose (BERR, 2007a, p.10). 11 Figure 1: Source: BERR (2007a, p.9) While recent rises in electricity and gas bills are driven by supply and demand in fossil fuel commodity markets, the impact of environmental factors on the final price... the public from dangers arising from the conveyance of gas through pipes or the use of gas conveyed through pipes and from the generation, transmission, distribution or supply of electricity; • Contribute to the achievement of sustainable development...

Pollitt, Michael G.

360

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

361

Gas Hydrates: It's A Gas!  

NSDL National Science Digital Library

In this activity, students will investigate the occurrence of gas hydrates on the ocean floor. They will discover the importance of carbon, where carbon is stored on Earth, and that the largest reservoir of carbon is gas hydrates. Students will discover that Earth's climate changes, and how the greenhouse effect works. They will also learn about the potential of hydrates as a major new energy resource and explore the conditions under which hydrates form.

362

Gas sensor  

SciTech Connect

An electro-chemical cell for quantitatively detecting an acidic or an alkaline gas, e.g. carbon dioxide, includes a sensing electrode which is connected to a top cap by a contact strip and is accessible to the gas to be tested through a hole. The electrode comprises an electro-chemical couple whose potential is pH-dependent (e.g. silver/silver oxide for carbon dioxide) the active material being supported by a nickel gauze to give good current collection. A counter electrode without significant gas access is immersed in an electrolyte whose pH is such that it will change following adsorption of the gas being tested for. A wicking separator ensures an electrolytic path between the two electrodes. The components are contained within a metal can, the top cap being held by folding over the rim. An insulating grommet is fitted between the two electrodes. When using silver/silver oxide for the sensing electrode, the counter electrode may be of the same material and the electrolyte may be potassium carbonate. The current flowing between the electrodes is a measure of the concentration of gas being detected. A reference electrode may also be included.

Tantram, A.D.S.; Finbow, J.R.; Hobbs, B.S.

1984-10-02

363

Dam Impacts  

NSDL National Science Digital Library

While the creation of a dam provides many benefits, it can have negative impacts on local ecosystems. Students learn about the major environmental impacts of dams and the engineering solutions used to address them.

Integrated Teaching And Learning Program

364

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING  

SciTech Connect

Efforts this quarter have concentrated on legal agreements, including alternative field sites. Preliminary design of the bench-scale equipment has been initiated. 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

365

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING  

SciTech Connect

Efforts this quarter have concentrated on legal agreements, including alternative field sites. Preliminary design of the bench-scale equipment continues. 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

2002-06-30

366

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 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. KPS 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. Efforts this quarter have concentrated on legal agreements, including alternative field sites. Preliminary design of the bench-scale equipment continues.

Howard S. Meyer

2002-10-01

367

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 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. Efforts this quarter have concentrated on legal agreements, including alternative field sites. Preliminary design of the bench-scale equipment continues.

Howard S. Meyer

2003-01-01

368

Gas Analyzer  

NASA Technical Reports Server (NTRS)

A miniature gas chromatograph, a system which separates a gaseous mixture into its components and measures the concentration of the individual gases, was designed for the Viking Lander. The technology was further developed under National Institute for Occupational Safety and Health (NIOSH) and funded by Ames Research Center/Stanford as a toxic gas leak detection device. Three researchers on the project later formed Microsensor Technology, Inc. to commercialize the product. It is a battery-powered system consisting of a sensing wand connected to a computerized analyzer. Marketed as the Michromonitor 500, it has a wide range of applications.

1983-01-01

369

The cost of natural gas shortages in Ireland  

Microsoft Academic Search

This paper investigates the economic implications of disruptions of one to ninety days to the supply of natural gas in Ireland. We assess the impact of a hypothetical gas supply disruption in both winter and summer in 2008 (with observed market characteristics) and in 2020 (with projected market characteristics). The cost of a natural gas outage includes the cost of

Eimear Leahy; Conor Devitt; Richard S. J. Tol

2012-01-01

370

The Cost of Natural Gas Shortages in Ireland  

Microsoft Academic Search

This paper investigates the economic implications of disruptions of one to ninety days to the supply of natural gas in Ireland. We assess the impact of a hypothetical gas supply disruption in both winter and summer in 2008 (with observed market characteristics) and in 2020 (with projected market characteristics). The cost of a natural gas outage includes the cost of

Eimear Leahy; Conor Devitt; Seán Lyons; Richard S. J. Tol

2011-01-01

371

Gas Chromatography  

NSDL National Science Digital Library

This site contains a brief introduction to the concepts of injection and detection in gas chromatography, focusing on the split/splitless injection port and flame ionization detectors. The treatment is similar to that in analytical chemistry textbooks, and includes detailed illustrations.

2011-05-25

372

Got Gas?  

NSDL National Science Digital Library

Create gas with a glass of water, some wire, conductors and a battery! You will be separating water (H2O) into oxygen and hydrogen. This hands-on experiment explores the process of electrolysis, and shows how graphite in a pencil works as an electrical conductor.

Centre, Discovery

1999-01-01

373

Impact accelerations  

NASA Technical Reports Server (NTRS)

The degree to which impact acceleration is an important factor in space flight environments depends primarily upon the technology of capsule landing deceleration and the weight permissible for the associated hardware: parachutes or deceleration rockets, inflatable air bags, or other impact attenuation systems. The problem most specific to space medicine is the potential change of impact tolerance due to reduced bone mass and muscle strength caused by prolonged weightlessness and physical inactivity. Impact hazards, tolerance limits, and human impact tolerance related to space missions are described.

Vongierke, H. E.; Brinkley, J. W.

1975-01-01

374

Nitrated polycyclic aromatic hydrocarbons in urban air particles  

Microsoft Academic Search

The organic extract of urban air particles from St. Louis, MO, was fractionated by high-performance liquid chromatography. The moderately polar fraction was characterized by gas chromatography-electron impact and methane negative ion chemical ionization mass spectrometry. The compounds identified in the sample included nitronaphthalene, 9-nitroanthracene, 3-nitrofluoranthene, 1-nitropyrene, arenecarbonitriles, and several polycyclic ketones, quinones, and anhydrides. These studies represent the first mass

Thomas Ramdahl; Georg Becher; A. Bjorseth

1982-01-01

375

Manage fuel gas with an expert system  

SciTech Connect

The Star Louisiana refinery has fuel gas header systems throughout the plant that are utilized by fuel gas producers and consumers. The refinery simultaneously exports surplus fuel gas from the export gas header, and maintains a minimum natural gas makeup rates from multiple external suppliers for fuel gas header pressure control. Successfully implementing a fuel gas expert system has facilitated communication of accurate, timely information to all unit control board operators in the refinery when any change or sub-optimal situation occurs in either of these systems. Information provided from the expert system rule knowledge base results in: proper unit operating actions taken when a flaring situation approaches, thus minimizing the negative impact of flaring on the environment and minimizing product loses to the flare; minimizing purchase of makeup natural gas used for fuel gas system pressure control; maximizing export gas capacity to prevent surplus fuel gas production from limiting refinery operation; immediately recognizing an upset in any fuel gas header system and advising the best corrective action for all affected refinery units; and minimizing voice communication required between units in an upset, since the expert system provides the communication immediately in expert advice messages.

Giacone, G.; Toben, S.; Bergeron, G. [Star Enterprise, Convent, LA (United States); Ayral, T. [Key Control Inc., Westlake Village, CA (United States)

1996-09-01

376

Natural gas 1994: Issues and trends  

SciTech Connect

This report provides an overview of the natural gas industry in 1993 and early 1994 (Chapter 1), focusing on the overall ability to deliver gas under the new regulatory mandates of Order 636. In addition, the report highlights a range of issues affecting the industry, including: restructuring under Order 636 (Chapter 2); adjustments in natural gas contracting (Chapter 3); increased use of underground storage (Chapter 4); effects of the new market on the financial performance of the industry (Chapter 5); continued impacts of major regulatory and legislative changes on the natural gas market (Appendix A).

Not Available

1994-07-01

377

Natural gas 1998: Issues and trends  

SciTech Connect

Natural Gas 1998: Issues and Trends provides a summary of the latest data and information relating to the US natural gas industry, including prices, production, transmission, consumption, and the financial and environmental aspects of the industry. The report consists of seven chapters and five appendices. Chapter 1 presents a summary of various data trends and key issues in today`s natural gas industry and examines some of the emerging trends. Chapters 2 through 7 focus on specific areas or segments of the industry, highlighting some of the issues associated with the impact of natural gas operations on the environment. 57 figs., 18 tabs.

NONE

1999-06-01

378

Gas Hydrates  

Microsoft Academic Search

This review states contemporary views about gas hydrates, and also about non-stoichiometric clathrates with the general formula M·nH2O. The known types of the hydrates and their crystal structure are described. The thermodynamics of hydrate formation is considered. Methods of determining the composition of the hydrates are described. Factual information concerning the hydrates of individual gases and organic liquids and mixed

S. Sh Byk; V. I. Fomina

1968-01-01

379

Projectile density, impact angle and energy effects on hypervelocity impact damage to carbon fibre\\/peek composites  

Microsoft Academic Search

This paper explores the effects of projectile density, impact angle and energy on the damage produced by hypervelocity impacts on carbon fibre\\/PEEK composites. Tests were performed using the light gas gun facilities at the University of Kent at Canterbury, UK, and the NASA Johnson Space Center two-stage light gas gun facilities at Rice University in Houston, Texas. Various density spherical

Chantal G. Lamontagne; Gerald N. Manuelpillai; Justin H. Kerr; Emma A. Taylor; Roderick C. Tennyson; Mark J. Burchell

2001-01-01

380

Pennsylvania's Natural Gas Future  

E-print Network

, President #12;UGI Propane Gas & Electric Domestic International Regulated Utilities Midstream & Marketing development (safety/regulation) · Aging and limited distribution infrastructure #12;Conclusion · Gas1 Pennsylvania's Natural Gas Future Penn State Natural Gas Utilization Workshop Bradley Hall

Lee, Dongwon

381

Gas Grill Fact Sheet  

MedlinePLUS

... year,thousands of people fire up their liquid propane (LP) or natural gas grills at the start ... possible gas explosions or fires. LP gas/liquid propane and natural gas are flammable. Many accidents occur ...

382

Note: Heated flyer-plate impact system.  

PubMed

A technique for launching heated flyer plates was developed on a single-stage gas gun. This type of impact creates a well-posed mechanical state and a tunable thermal state, which is useful for calibrating dynamic temperature measurements. Proof-of-principle thermoreflectance measurements were performed using this technique. Since the target remains at room temperature until the moment of impact, heated flyers avoid differential expansion and annealing issues, allowing novel impact experiments to be performed. PMID:25085187

Dolan, D H; Seagle, C T; Ao, T; Hacking, R G

2014-07-01

383

76 FR 381 - Notice of Availability of the Draft Environmental Impact Statement/Draft Environmental Impact...  

Federal Register 2010, 2011, 2012, 2013

...Impact Report for the Iberdrola Renewable/Pacific Wind Development Tule Wind Project and San Diego Gas and Electric's East County...analysis document for the Iberdrola Renewable/Pacific Wind Development Tule Wind Project (Tule Project)...

2011-01-04

384

Earth Impact  

NSDL National Science Digital Library

This activity poses the question: What would happen if a meteor or comet impacted Earth? Students simulate an impact in a container of sand using various-sized rocks, all while measuring, recording and graphing results and conclusions. Then students brainstorm ways to prevent an object from hitting the Earth.

Integrated Teaching And Learning Program

385

Maneuvering impact boring head  

DOEpatents

An impact boring head may comprise a main body having an internal cavity with a front end and a rear end. A striker having a head end and a tail end is slidably mounted in the internal cavity of the main body so that the striker can be reciprocated between a forward position and an aft position in response to hydraulic pressure. A compressible gas contained in the internal cavity between the head end of the striker and the front end of the internal cavity returns the striker to the aft position upon removal of the hydraulic pressure.

Zollinger, W. Thor (Idaho Falls, ID); Reutzel, Edward W. (Idaho Falls, ID)

1998-01-01

386

Impact nailing arrangement  

US Patent & Trademark Office Database

An impact nailing arrangement having a nail with integral pointed target-penetration and securing forward section, rear hammer section, and medial compression shear section, the forward section having a threaded object-securing surface rearwardly of its pointed forward target-securing end. The nail is propelled into a target in the preferred embodiment by any one of several illustrated latent energy means, and the forward section is secured by initial point penetration and subsequent compression shear of the medial shear section to enable the hammer section to impart a secondary securing impact to the forward section. Various alternative propulsion arrangements including electrical actuation of a powder charge, spring actuation, and valved pressurized gas, are disclosed.

1979-06-26

387

Is the U.S. shale gas boom having an effect on the European gas market?  

NASA Astrophysics Data System (ADS)

This thesis focuses on the impact of the American shale gas boom on the European natural gas market. The study presents different tests in order to analyze the dynamics of natural gas prices in the U.S., U.K. and German natural gas market. The question of cointegration between these different markets are analyzed using several tests. More specifically, the ADF tests for the presence of a unit root. The error correction model test and the Johansen cointegration procedure are applied in order to accept or reject the hypothesis of an integrated market. The results suggest no evidence of cointegration between these markets. There currently is no evidence of an impact of the U.S. shale gas boom on the European market.

Yao, Isaac

388

The Public Heath Implications of Unconventional Gas Drilling For presentation to the  

E-print Network

is concerned about the potential health impacts of unconventional shale gas development; 2) there is genuine information they are receiving about two important aspects of unconventional shale gas drilling. The nation

Jiang, Huiqiang

389

Gas Hydrates: It's a Gas  

NSDL National Science Digital Library

In this activity, students will discover the importance of carbon, where carbon is stored on Earth, and that the largest reservoir of carbon is in the form of gas hydrates where methane and other hydrocarbon gases are trapped in a lattice of water molecules in deep sea sediments. Students will learn how climate change is related to the greenhouse effect. They will also learn about the potential of hydrates as a major new energy resource, and explore the conditions under which hydrates form. In addition, students will understand the use of acoustics for mapping the sea floor and sub-sea floor.

390

Dynamics of a Single Reactive Gas Bubble  

Microsoft Academic Search

\\u000a The dynamics of a single combustible stoichiometric oxyacetylene gas bubble immersed in glycerine subjected to an impulsive\\u000a pressure wave has been studied experimentally and theoretically. Emphasis is placed on determining the range of bubble sizes\\u000a over which ignition of the gas occurs after the passage of a pressure pulse generated by the impact of a projectile with a\\u000a piston. Bubbles

B. Bruckert; D. L. Frost; A. N. Meidani; R. Chue; M. Brouillette

391

Gas Chromatography  

NSDL National Science Digital Library

This video, distributed on YouTube by the Royal Society of Chemistry, is on the basic principles of Gas Chromatography. This video is a short primer which introduces the technique and instrumentation. There are many assumptions that are made in the presentation of this material, due to the fact the video is meant to be a basic introduction. The ultimate strength of this video is the general nature of the content that makes it appealing to a wide audience. The video may be most appropriate in a lower-level general education science course (i.e forensic science) or as a quick orientation video for instrumental analysis students. The GC-FID and GC-MS are highlighted. Running time for the video is 5:17.

2011-05-26

392

Deep Impact: Observations from a Worldwide Earth-Based Campaign  

Microsoft Academic Search

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P\\/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas

K. J. Meech; N. Ageorges; M. F. A'Hearn; C. Arpigny; A. Ates; J. Aycock; S. Bagnulo; J. Bailey; R. Barber; L. Barrera; R. Barrena; J. M. Bauer; M. J. S. Belton; F. Bensch; B. Bhattacharya; N. Biver; G. Blake; D. Bockelée-Morvan; H. Boehnhardt; B. P. Bonev; T. Bonev; M. W. Buie; M. G. Burton; H. M. Butner; R. Cabanac; R. Campbell; H. Campins; M. T. Capria; T. Carroll; F. Chaffee; S. B. Charnley; R. Cleis; A. Coates; A. Cochran; P. Colom; A. Conrad; I. M. Coulson; J. Crovisier; J. deBuizer; R. Dekany; J. de Léon; N. Dello Russo; A. Delsanti; M. DiSanti; J. Drummond; L. Dundon; P. B. Etzel; T. L. Farnham; P. Feldman; Y. R. Fernández; M. D. Filipovic; S. Fisher; A. Fitzsimmons; D. Fong; R. Fugate; H. Fujiwara; T. Fujiyoshi; R. Furusho; T. Fuse; E. Gibb; O. Groussin; S. Gulkis; M. Gurwell; E. Hadamcik; O. Hainaut; D. Harker; D. Harrington; M. Harwit; S. Hasegawa; C. W. Hergenrother; P. Hirst; K. Hodapp; M. Honda; E. S. Howell; D. Hutsemékers; D. Iono; W.-H. Ip; W. Jackson; E. Jehin; Z. J. Jiang; G. H. Jones; P. A. Jones; T. Kadono; U. W. Kamath; H. U. Käufl; T. Kasuga; H. Kawakita; M. S. Kelley; F. Kerber; M. Kidger; D. Kinoshita; M. Knight; L. Lara; S. M. Larson; S. Lederer; C.-F. Lee; A. C. Levasseur-Regourd; J. Y. Li; Q.-S. Li; J. Licandro; Z.-Y. Lin; C. M. Lisse; G. LoCurto; A. J. Lovell; S. C. Lowry; J. Lyke; D. Lynch; J. Ma; K. Magee-Sauer; G. Maheswar; J. Manfroid; O. Marco; P. Martin; G. Melnick; S. Miller; T. Miyata; G. H. Moriarty-Schieven; N. Moskovitz; B. E. A. Mueller; M. J. Mumma; S. Muneer; D. A. Neufeld; T. Ootsubo; D. Osip; S. K. Pandea; E. Pantin; R. Paterno-Mahler; B. Patten; B. E. Penprase; A. Peck; G. Petitpas; N. Pinilla-Alonso; J. Pittichova; E. Pompei; T. P. Prabhu; C. Qi; R. Rao; H. Rauer; H. Reitsema; S. D. Rodgers; P. Rodriguez; R. Ruane; G. Ruch; W. Rujopakarn; D. K. Sahu; S. Sako; I. Sakon; N. Samarasinha; J. M. Sarkissian; I. Saviane; M. Schirmer; P. Schultz; R. Schulz; P. Seitzer; T. Sekiguchi; F. Selman; M. Serra-Ricart; R. Sharp; R. L. Snell; C. Snodgrass; T. Stallard; G. Stecklein; C. Sterken; J. A. Stüwe; S. Sugita; M. Sumner; N. Suntzeff; R. Swaters; S. Takakuwa; N. Takato; J. Thomas-Osip; E. Thompson; A. T. Tokunaga; G. P. Tozzi; H. Tran; M. Troy; C. Trujillo; J. Van Cleve; R. Vasundhara; R. Vazquez; F. Vilas; G. Villanueva; K. von Braun; P. Vora; R. J. Wainscoat; K. Walsh; J. Watanabe; H. A. Weaver; W. Weaver; M. Weiler; P. R. Weissman; W. F. Welsh; D. Wilner; S. Wolk; M. Womack; D. Wooden; L. M. Woodney; C. Woodward; Z.-Y. Wu; J.-H. Wu; T. Yamashita; B. Yang; Y.-B. Yang; S. Yokogawa; A. C. Zook; A. Zauderer; X. Zhao; X. Zhou; J.-M. Zucconi

2005-01-01

393

Phenomena of liquid drop impact on solid and liquid surfaces  

Microsoft Academic Search

The fluid dynamic phenomena of liquid drop impact are described and reviewed. These phenomena include bouncing, spreading and splashing on solid surfaces, and bouncing, coalescence and splashing on liquid surfaces. Further, cavitation and the entrainment of gas into an impacted liquid may be observed. In order to distinguish properly between the results of different experiments different impact scenarios are discussed.

Martin Rein

1993-01-01

394

What you need to know about environmental impact statements  

Microsoft Academic Search

Environmental Research and Technology, Inc., offers practical information on environmental-impact statements and the associated regulatory practices that confront gas-processing management when seeking federal approval for expansion, modernization, and new construction projects. The report defines the impact statement and its relation to project approvals, describes the company's role in assessing the project's environmental impact, presents guidelines for environmental planning, and discusses

B. H. Willis; W. M. Henebry

1976-01-01

395

Impact Cratering  

NSDL National Science Digital Library

This Lunar and Planetary Institute webpage provides information about the characteristics and formation of impact craters on Earth and the moon. Earth's significant impact craters are described, and the difference in cratering on Earth and moon is explained. Craters on Earth, the moon, and Mars are pictured. The page is illustrated with images of craters, and is nicely organized into a series of questions and answers.

Institute, Lunar A.

2012-07-27

396

COMBUSTION MODIFICATION CONTROLS FOR STATIONARY GAS TURBINE. VOLUME I: ENVIRONMENTAL ASSESSMENT  

EPA Science Inventory

The report gives an environmental assessment of combustion modification techniques for stationary gas turbines, with respect to NOx control effectiveness, operational impact, thermal efficiency impact, control costs, and effect on emissions of pollutants other than NOx....

397

Natural Gas Regulatory Policy: Current Issues  

E-print Network

the options of industrial energy consumers for purchasing and moving natural gas. This panel viII discuss important developments in federal and state regulatory arenas and their impacts on purchasing options. Among the issues discussed viII be: 1.... Federal Regulation a. Self-implementing transportation b. Service obligation c. Pipeline capacity brokering d. Non-regulated and partially regulated sales e. FERC Order No. 500 f. Rate treatments impacts 2. State Regulation a...

Watkins, G.

398

Anesthesia and gas exchange in tracheal surgery.  

PubMed

Tracheobronchial surgery constitutes a challenge to the anesthetist because it involves the anatomic structures dedicated to bulk gas transport. Common approaches to airway management and gas exchange for extrathoracic and intrathoracic airway surgery are reviewed, with due regard to less common methods thought crucial for specific procedures. Tracheal surgery, beyond sharing the airways, requires sharing with the surgeon ideas on preoperative assessment, on the impact on gas exchange of induction across compromised airways, and of emergence from anesthesia with airways altered by surgical repair. Mutual understanding is essential to prevent, rapidly identify, and correct imminent loss of airway viability. PMID:24295656

Wiedemann, Klaus; Männle, Clemens

2014-02-01

399

Impact beyond the impact factor.  

PubMed

The journal impact factor is an annually calculated number for each scientific journal, based on the average number of times its articles published in the two preceding years have been cited. It was originally devised as a tool for librarians and publishers to provide information about the citation performance of a journal as a whole, but over the last few decades it has increasingly been used to assess the quality of specific articles and the research performance of individual investigators, institutions, and countries. In addition to this clear abuse of the journal impact factor, several conceptual and technical issues limit its usability as a measure of journal reputation, especially when journals are compared across different fields. An author's decision regarding the suitability of a scholarly journal for publication should, therefore, be based on the impact that this journal makes in the field of research, rather than on the journal impact factor. PMID:24264238

Zupanc, Günther K H

2014-02-01

400

Resilience-Based Design of Natural Gas Distribution Networks  

E-print Network

). Then the gas distribution network has a significant impact on the Italian national economy; however, because of the remainder being hydroelectric energy and a smaller percentage being renewable sources (e.g., wind and solar and the economy of the

Bruneau, Michel

401

Macroeconomic impacts of energy shocks  

SciTech Connect

This study compares the responses of 14 macroeconomic models to supply-side shocks in the form of sudden energy price increases or decreases and to policies for lessening the impacts of price jumps. Four energy price shocks were examined: oil price increases of 50 and 20 percent, an oil price reduction of 20 percent, and an 80 percent increase in domestic natural gas prices. Five policy responses were considered for offsetting the GNP impacts of the larger oil price increase: monetary accommodation, an income tax rate reduction, an increase in the investment tax credit for equipment, a reduction in the employer's payroll tax rate, and an oil stockpile release.

Hickman, B.G.; Huntington, H.G.; Sweeney, J.L.

1987-01-01

402

Impact of N{sub 2} and forming gas plasma exposure on the growth and interfacial characteristics of Al{sub 2}O{sub 3} on AlGaN  

SciTech Connect

The interface and atomic layer deposition (ALD) of Al{sub 2}O{sub 3} on the annealed, N{sub 2} plasma and forming gas (N{sub 2}:H{sub 2}) exposed Al{sub 0.25}Ga{sub 0.75}N surface was studied using in situ X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. Exposure of the Al{sub 0.25}Ga{sub 0.75}N surface to the plasma treatments is able to remove spurious carbon, and readily facilitate uniform ALD Al{sub 2}O{sub 3} nucleation.

Qin, Xiaoye; Dong, Hong; Brennan, Barry; Azacatl, Angelica; Kim, Jiyoung; Wallace, Robert M. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)] [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)

2013-11-25

403

Gas amplified ionization detector for gas chromatography  

DOEpatents

A gas-amplified ionization detector for gas chromatrography which possesses increased sensitivity and a very fast response time. Solutes eluding from a gas chromatographic column are ionized by UV photoionization of matter eluting therefrom. The detector is capable of generating easily measured voltage signals by gas amplification/multiplication of electron products resulting from the UV photoionization of at least a portion of each solute passing through the detector.

Huston, Gregg C. (LaBelle, PA)

1992-01-01

404

Impact: Earth!  

NSDL National Science Digital Library

What would happen if a large meteorite or other object hit the Earth? It's something that has engaged the minds and talents of astrophysicists (and students of all ages) for decades. Now the generally curious can create their own simulated impact with Purdue University's "Impact Earth" website. Visitors can browse the Famous Craters area to get started. This part includes some "classics," such as the Ries Crater and the Tunguska Fireball. Of course, visitors really must use the handy interface to craft their own impact, projectile, and target parameters to get the full effect on how such an event plays out. Also, the site includes a complete Documentation file (a peer-reviewed article) and a detailed glossary.

2013-01-01

405

Ideal Gas Law and the Gas Constant  

NSDL National Science Digital Library

This site offers an interactive tutorial in which students test the validity of the ideal gas law by measuring the pressure of a gas at various molar concentrations. The value of the gas constant is determined graphically. This tutorial is coupled to others to further guide the student to a better understanding of the principles which govern the behavior of gases.

Blauch, David N.

406

Impact Crater  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Today marks the 45th anniversary of the dawn of the Space Age (October 4, 1957). On this date the former Soviet Union launched the world's first satellite, Sputnik 1. Sputnik means fellow traveler. For comparison Sputnik 1 weighed only 83.6 kg (184 pounds) while Mars Odyssey weighs in at 758 kg (1,671 pounds).

This scene shows several interesting geologic features associated with <