WorldWideScience

Sample records for acid gas hazards

  1. [Chemical hazards arising from shale gas extraction].

    OpenAIRE

    Daria Pakulska

    2015-01-01

    The development of the shale industry is gaining momentum and hence the analysis of chemical hazards to the environment and health of the local population is extremely timely and important. Chemical hazards are created during the exploitation of all minerals, but in the case of shale gas production, there is much more uncertainty as regards to the effects of new technologies application. American experience suggests the increasing risk of environmental contamination, mainly groundwater. The g...

  2. [Chemical hazards arising from shale gas extraction].

    Science.gov (United States)

    Pakulska, Daria

    2015-01-01

    The development of the shale industry is gaining momentum and hence the analysis of chemical hazards to the environment and health of the local population is extreiely timely and important. Chemical hazards are created during the exploitation of all minerals, but in the case of shale gas production, there is much more uncertainty as regards to the effects of new technologies application. American experience suggests the increasing risk of environmental contamination, mainly groundwater. The greatest, concern is the incomplete knowledge of the composition of fluids used for fracturing shale rock and unpredictability of long-term effects of hydraulic fracturing for the environment and health of residents. High population density in the old continent causes the problem of chemical hazards which is much larger than in the USA. Despite the growing public discontent data on this subject are limited. First of all, there is no epidemiological studies to assess the relationship between risk factors, such as air and water pollution, and health effects in populations living in close proximity to gas wells. The aim of this article is to identify and discuss existing concepts on the sources of environmental contamination, an indication of the environment elements under pressure and potential health risks arising from shale gas extraction.

  3. Chemical hazards arising from shale gas extraction

    Directory of Open Access Journals (Sweden)

    Daria Pakulska

    2015-02-01

    Full Text Available The development of the shale industry is gaining momentum and hence the analysis of chemical hazards to the environment and health of the local population is extremely timely and important. Chemical hazards are created during the exploitation of all minerals, but in the case of shale gas production, there is much more uncertainty as regards to the effects of new technologies application. American experience suggests the increasing risk of environmental contamination, mainly groundwater. The greatest concern is the incomplete knowledge of the composition of fluids used for fracturing shale rock and unpredictability of long-term effects of hydraulic fracturing for the environment and health of residents. High population density in the old continent causes the problem of chemical hazards which is much larger than in the USA. Despite the growing public discontent data on this subject are limited. First of all, there is no epidemiological studies to assess the relationship between risk factors, such as air and water pollution, and health effects in populations living in close proximity to gas wells. The aim of this article is to identify and discuss existing concepts on the sources of environmental contamination, an indication of the environment elements under pressure and potential health risks arising from shale gas extraction. Med Pr 2015;66(1:99–117

  4. Structural comparison of hazardous and non-hazardous coals based on gas sorption experiments

    Energy Technology Data Exchange (ETDEWEB)

    Lakatos, J.; Toth, J. [Research Lab. for Mining Chemistry, Hungarian Academy of Sciences, Miskolc-Egyetemvaros (Hungary); Radnai-Gyoengyoes, Z. [Geopard Ltd., Pecs (Hungary); Bokanyi, L. [Miskolc Univ., Miskolc-Egyetemvaros (Hungary). Dept. of Process Engineering

    1997-12-31

    Comparison of carbon-dioxide and propane sorption at ambient temperature was used for characterising the difference of the structure of hazardous and non hazardous coals. However, hazardous coals were found more microporous or contain more closed pores than non hazardous ones, this difference couldn`t have been enlarged and attributed to one petrographic component by producing the density fractions. Gas sorption isobars (nitrogen, methane, ethane) are proposed to make a distinction between fine pore structure of coals. (orig.)

  5. Hazard assessments of double-shell flammable gas tanks

    Energy Technology Data Exchange (ETDEWEB)

    Fox, G.L.; Stepnewski, D.D.

    1994-09-28

    This report is the fourth in a series of hazard assessments performed on the double-shell flammable gas watch list tanks. This report focuses on hazards associated with the double-shell watch list tanks (101-AW, 103-AN, 104-AN, and 105-AN). While a similar assessment has already been performed for tank 103-SY, it is also included here to incorporate a more representative slurry gas mixture and provide a consistent basis for comparing results for all the flammable gas tanks. This report is intended to provide an in-depth assessment by considering the details of the gas release event and slurry gas mixing as the gas is released from the waste. The consequences of postulated gas ignition are evaluated using a plume burn model and updated ignition frequency predictions. Tank pressurization which results from a gas burn, along with the structural response, is also considered. The report is intended to support the safety basis for work activities in flammable gas tanks by showing margins to safety limits that are available in the design and procedures.

  6. Evaluation of occupational gas and dust hazards - abstracts of papers

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    Abstracts of 13 papers are presented. The occupational hazards, generation and harmful effects of toxic gases and vapours are discussed, and the additional risks of fire and explosions encountered with flammable gases are described. Airborne dust (i.e. particulates and fibres capable of entering the respiratory system) and the health effects of these (e.g. pneumoconioses, respiratory tract cancers and allergic alveolitis), with special emphasis on asbestos and other mineral fibres, are considered. The regulations concerning the control of hazardous substances and the practicalities of meeting these are covered, with details of gas detectors, monitoring instruments and sampling techniques. Total, respirable and inhalable dusts are distinguished.

  7. Acid Gas Removal from Natural Gas with Alkanolamines

    DEFF Research Database (Denmark)

    Sadegh, Negar

    Some 40 % of the world’s remaining gas reserves are sour or acid, containing large quantities of CO2 and H2S and other sulfur compounds. Many large oil and gas fields have more than 10 mole % CO2 and H2S content. In the gas processing industry absorption with chemical solvents has been used...... commercially for the removal of acid gas impurities from natural gas. Alkanolamines, simple combinations of alcohols and ammonia, are the most commonly used category of chemical solvents for acid gas capture. This Ph.D. project is aboutthermodynamics of natural gas cleaning process with alkanolamines...... pressure on acid gas solubility was also quantitatively investigated through both experimental and modeling approaches....

  8. Chemical hazards from acid crater lakes

    Science.gov (United States)

    van Bergen, M. J.; Sumarti, S.; Heikens, A.; Bogaard, T. A.; Hartiyatun, S.

    2003-04-01

    Acid crater lakes, which are hosted by a considerable number of active volcanoes, form a potential threat for local ecosystems and human health, as they commonly contain large amounts of dissolved chemicals. Subsurface seepage or overflow can lead to severe deterioration of the water quality of rivers and wells, as observations around several of these volcanoes have shown. The Ijen crater lake in East Java (Indonesia) is a striking example, as this reservoir of hyperacid (pHdental fluorosis is widespread among the ca. 100,000 residents of the area. A conspicuous spatial correlation between fluoride concentrations and the irrigation system suggest that long-term (century) infiltration of irrigation water may have affected the quality of groundwater. Fluorosis is also a problem in some villages within the caldera, where well water sources may have a more direct subsurface connection with the lake system. From our observations we conclude that water-quality monitoring is especially needed for health reasons in volcanic areas where volatile elements, derived from passively degassing magma, are intercepted by (sub) surface water bodies.

  9. Nanostructure Engineered Chemical Sensors for Hazardous Gas and Vapor Detection

    Science.gov (United States)

    Li, Jing; Lu, Yijiang

    2005-01-01

    A nanosensor technology has been developed using nanostructures, such as single walled carbon nanotubes (SWNTs) and metal oxides nanowires or nanobelts, on a pair of interdigitated electrodes (IDE) processed with a silicon based microfabrication and micromachining technique. The IDE fingers were fabricated using thin film metallization techniques. Both in-situ growth of nanostructure materials and casting of the nanostructure dispersions were used to make chemical sensing devices. These sensors have been exposed to hazardous gases and vapors, such as acetone, benzene, chlorine, and ammonia in the concentration range of ppm to ppb at room temperature. The electronic molecular sensing in our sensor platform can be understood by electron modulation between the nanostructure engineered device and gas molecules. As a result of the electron modulation, the conductance of nanodevice will change. Due to the large surface area, low surface energy barrier and high thermal and mechanical stability, nanostructured chemical sensors potentially can offer higher sensitivity, lower power consumption and better robustness than the state-of-the-art systems, which make them more attractive for defense and space applications. Combined with MEMS technology, light weight and compact size sensors can be made in wafer scale with low cost.

  10. Interfacial Evolution and Migration Characteristics of Acid Gas Injected into a Saline Aquifer

    Institute of Scientific and Technical Information of China (English)

    YU Bo; LIU Yongzhong; LIANG Xiaoqiang; WANG Le

    2013-01-01

    Acid gas injection into saline aquifers is one of promising ways to reduce greenhouse gas emissions and to dispose hazardous waste simultaneously.On the basis of Level Set method,an improved mathematical model that described interfacial dynamics of acid gas-brine system in a deep confined saline aquifer was proposed for predicting the propagation of the acid gas plume,which was featured by using Peng-Robinson equation and modified Lucas equation to describe variations of the density and viscosity of acid gas in saline aquifers.The evolutional characteristics of acid gas plume were obtained through numerical simulations using COMSOL Multiphysics 3.5a.The results showed that under intrinsic characteristics of aquifers and operational conditions given,the variation of acid gas density was the major factor that influences the patterns and shapes of the plume.The leading edge position of acid gas plume was intensively dependent on the acid gas composition.Under the scheme of fixed mass flow rate injection,as the molar fraction of H2S increased,the position of leading edge advanced gradually towards the injection well.Moreover,the estimation of the storage efficiency of acid gas in saline aquifers was clarified and discussed.The proposed approach and the simulation results will provide insights into the determination of optimal operational strategies and rapid identification of the consequences of acid gas injection into deep confined saline aquifers.

  11. Karst hazard assessment in the design of the main gas pipeline (South Yakutia)

    Science.gov (United States)

    Strokova, L. A.; Dutova, E. M.; Ermolaeva, A. V.; Alimova, I. N.; Strelnikova, A. B.

    2015-11-01

    The paper represents the description of the zonal and regional geological factors of geoengineering conditions which characterize the territory in South Yakutia crossed by the designed main gas pipeline. Cryogenic processes and karst are considered to be the most dangerous hazards for gas pipeline maintenance. Karst hazard assessment of the gas pipeline section made in the course of the research has involved a complex of geological methods: geoengineering, geophysical, hydrogeological, and mapping. Sections prone to karst development have been identified. The authors have suggested the measures to protect potentially hazardous sections and to ensure timely informing on sinkhole collapses.

  12. Pattern recognition prediction of coal and gas outburst hazard in the sixth mine of Hebi

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-wei; SONG Wei-hua; YANG Heng; ZHANG Ming-jie

    2008-01-01

    Based on the systematical analysis influence factors of coal and gas outburst,the main factors and their magnitude was determined by the corresponding methods. With the research region divided into finite predicting units, the internal relation between the factors and the hazard of coal and gas outburst, that was combination model of influence factors, was ascertained through multi-factor pattern recognition method. On the basis of contrastive analysis the pattern of coal and gas outburst between prediction region and mined region, the hazard of every predication unit was determined. The mining area was then divided into coal and gas outburst dangerous area, threaten area and safe area respectively according to the hazard of every predication unit. Accordingly the hazard of mining area is assessed.

  13. Research on safety assessment of gas explosion hazard in heading face based on BP neural network

    Institute of Scientific and Technical Information of China (English)

    TIAN Shui-cheng; ZHU Li-jun; CHEN Yong-gang; WANG Li

    2005-01-01

    According to hazard theory and the principle of selecting assessment index,combining the causes and mechanism of gas explosion, established assessment index system of gas explosion in heading face. Based on the method of gray clustering, principle of BP neural network and characters of gas explosion in heading face, safety assessment procedural diagram of BP neural network on gas explosion hazard in heading face is designed. Meanwhile, concrete heading face of the gas explosion hazard is assessed by safety assessment method of BP neural network and grades of comprehensive safety assessment are got. The static and dynamic safety assessment can be achieved by this method. It is practical to improve safety management and to develop safety assessment technology in coalmine.

  14. Gas-phase Acidities of Aspartic Acid, Glutamic Acid, and their Amino Acid Amides.

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhong; Matus, Myrna H; Velazquez, Hector A; Dixon, David A; Cassady, Carolyn J

    2007-02-14

    Gas-phase acidities (GA or ΔGacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage’s importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3–4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2- group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

  15. Gas-phase acidities of aspartic acid, glutamic acid, and their amino acid amides

    Science.gov (United States)

    Li, Zhong; Matus, Myrna H.; Velazquez, Hector Adam; Dixon, David A.; Cassady, Carolyn J.

    2007-09-01

    Gas-phase acidities (GA or [Delta]Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage's importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3-4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2- group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

  16. Hazard-Specific Vulnerability Mapping for Water Security in a Shale Gas Context

    Science.gov (United States)

    Allen, D. M.; Holding, S.; McKoen, Z.

    2015-12-01

    Northeast British Columbia (NEBC) is estimated to hold large reserves of unconventional natural gas and has experienced rapid growth in shale gas development activities over recent decades. Shale gas development has the potential to impact the quality and quantity of surface and ground water. Robust policies and sound water management are required to protect water security in relation to the water-energy nexus surrounding shale gas development. In this study, hazard-specific vulnerability mapping was conducted across NEBC to identify areas most vulnerable to water quality and quantity deterioration due to shale gas development. Vulnerability represents the combination of a specific hazard threat and the susceptibility of the water system to that threat. Hazard threats (i.e. potential contamination sources and water abstraction) were mapped spatially across the region. The shallow aquifer susceptibility to contamination was characterised using the DRASTIC aquifer vulnerability approach, while the aquifer susceptibility to abstraction was mapped according to aquifer productivity. Surface water susceptibility to contamination was characterised on a watershed basis to describe the propensity for overland flow (i.e. contaminant transport), while watershed discharge estimates were used to assess surface water susceptibility to water abstractions. The spatial distribution of hazard threats and susceptibility were combined to form hazard-specific vulnerability maps for groundwater quality, groundwater quantity, surface water quality and surface water quantity. The vulnerability maps identify priority areas for further research, monitoring and policy development. Priority areas regarding water quality occur where hazard threat (contamination potential) coincide with high aquifer susceptibility or high overland flow potential. Priority areas regarding water quantity occur where demand is estimated to represent a significant proportion of estimated supply. The identification

  17. An assessment of gas emanation hazard using a geographic information system and geostatistics.

    Science.gov (United States)

    Astorri, F; Beaubien, S E; Ciotoli, G; Lombardi, S

    2002-03-01

    This paper describes the use of geostatistical analysis and GIS techniques to assess gas emanation hazards. The Mt. Vulsini volcanic district was selected for this study because of the wide range of natural phenomena locally present that affect gas migration in the near surface. In addition, soil gas samples that were collected in this area should allow for a calibration between the generated risk/hazard models and the measured distribution of toxic gas species at surface. The approach used during this study consisted of three general stages. First data were digitally organized into thematic layers, then software functions in the GIS program "ArcView" were used to compare and correlate these various layers, and then finally the produced "potential-risk" map was compared with radon soil gas data in order to validate the model and/or to select zones for further, more-detailed soil gas investigations.

  18. Forecasting and Evaluation of Gas Pipelines Geometric Forms Breach Hazard

    Science.gov (United States)

    Voronin, K. S.

    2016-10-01

    Main gas pipelines during operation are under the influence of the permanent pressure drops which leads to their lengthening and as a result, to instability of their position in space. In dynamic systems that have feedback, phenomena, preceding emergencies, should be observed. The article discusses the forced vibrations of the gas pipeline cylindrical surface under the influence of dynamic loads caused by pressure surges, and the process of its geometric shape deformation. Frequency of vibrations, arising in the pipeline at the stage preceding its bending, is being determined. Identification of this frequency can be the basis for the development of a method of monitoring the technical condition of the gas pipeline, and forecasting possible emergency situations allows planning and carrying out in due time reconstruction works on sections of gas pipeline with a possible deviation from the design position.

  19. Hazard of ultraviolet radiation emitted in gas tungsten arc welding of aluminum alloys.

    Science.gov (United States)

    Nakashima, Hitoshi; Utsunomiya, Akihiro; Fujii, Nobuyuki; Okuno, Tsutomu

    2016-01-01

    Ultraviolet radiation (UVR) emitted during arc welding frequently causes keratoconjunctivitis and erythema. The extent of the hazard of UVR varies depending on the welding method and conditions. Therefore, it is important to identify the levels of UVR that are present under various conditions. In this study, we experimentally evaluated the hazard of UVR emitted in gas tungsten arc welding (GTAW) of aluminum alloys. The degree of hazard of UVR is measured by the effective irradiance defined in the American Conference of Governmental Industrial Hygienists guidelines. The effective irradiances measured in this study are in the range 0.10-0.91 mW/cm(2) at a distance of 500 mm from the welding arc. The maximum allowable exposure times corresponding to these levels are only 3.3-33 s/day. This demonstrates that unprotected exposure to UVR emitted by GTAW of aluminum alloys is quite hazardous in practice. In addition, we found the following properties of the hazard of UVR. (1) It is more hazardous at higher welding currents than at lower welding currents. (2) It is more hazardous when magnesium is included in the welding materials than when it is not. (3) The hazard depends on the direction of emission from the arc.

  20. Risk Assessment for Natural Gas Hydrate Carriers: A Hazard Identification (HAZID Study

    Directory of Open Access Journals (Sweden)

    Kipyoung Kim

    2015-04-01

    Full Text Available Sea transport of natural gas in the form of hydrate pellets is a new technological approach. Introducing new technologies bears raises the possibility of introducing unknown risks or—in case of alternatives for already existing technical solutions—higher risk, either human-, environmental-, or property-related. The option of gas transport by natural gas hydrate pellets has been introduced within the Korean joint research project. One key task was the safety evaluation of the novel natural gas hydrate carrier (NGH carrier developed in the project. The aim of this work was to support and assess the risk aspects of the development to ensure that the risk level for the newly developed concept is as low as for existing competing concepts, especially LNG carriers. The NGH carrier is based on the concept of the self-preservation effect and thereby preserves NGH in the form of pellets at atmospheric pressure and temperatures lower than −20 °C. In order to identify all the possible hazards in the system and then enhance the system safety, a Hazard Identification (HAZID study was conducted. As a result of the HAZID, 80 identified hazards in total were explored and ranked in terms of risk index for the semi-quantitative risk evaluation. Among the hazards identified, three hazards were found to have unacceptable risk level and twenty eight to have acceptable but ALARP risk level. Regarding the hazards with unacceptable risk or ALARP risk, additional safety actions and recommendations for risk control were discussed and proposed in a SAFETY ACTION REGISTER, which would be considered and utilized by designers when developing the detailed system design in the future. In conclusion, the overall safety level of the NGH carrier is considered acceptable. However, it was found that a few external hazards associated with extremely harsh weather could be critical threats to the system. Relevant safety actions against them, therefore, must be provided in the

  1. Thermal Hazard Evaluation of Lauroyl Peroxide Mixed with Nitric Acid

    Directory of Open Access Journals (Sweden)

    Chi-Min Shu

    2012-07-01

    Full Text Available Many thermal runaway incidents have been caused by organic peroxides due to the peroxy group, –O–O–, which is essentially unstable and active. Lauroyl peroxide (LPO is also sensitive to thermal sources and is incompatible with many materials, such as acids, bases, metals, and ions. From the thermal decomposition reaction of various concentrations of nitric acid (HNO3 (from lower to higher concentrations with LPO, experimental data were obtained as to its exothermic onset temperature (T0, heat of decomposition (ΔHd, isothermal time to maximum rate (TMRiso, and other safety parameters exclusively for loss prevention of runaway reactions and thermal explosions. As a novel finding, LPO mixed with HNO3 can produce the detonation product of 1-nitrododecane. We used differential scanning calorimetry (DSC, thermal activity monitor III (TAM III, and gas chromatography/mass spectrometer (GC/MS analyses of the reactivity for LPO and itself mixed with HNO3 to corroborate the decomposition reactions and reaction mechanisms in these investigations.

  2. 78 FR 53190 - Pipeline Safety: Notice to Operators of Hazardous Liquid and Natural Gas Pipelines of a Recall on...

    Science.gov (United States)

    2013-08-28

    ... Liquid and Natural Gas Pipelines of a Recall on Leak Repair Clamps Due to Defective Seal AGENCY: Pipeline... seal. Hazardous liquid and natural gas pipeline operators should ] verify if they have any TDW LRCs... and Flanged Fittings. These LRCs were manufactured for use on hazardous liquid and natural...

  3. Forecast of Geological Gas Hazards for "Three-Soft" Coal Seams in Gliding Structural Areas

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Gas outbursts from "three-soft" coal seams (soft roof, soft floor and soft coal) constitute a very serious problem in the Ludian gliding structure area in western Henan.By means of theories and methods of gas geology, structural geology, coal petrology and rock tests, we have discussed the effect of control of several physical properties of soft roof on gas preservation and proposed a new method of forecasting gas geological hazards under open structural conditions.The result shows that the areas with type Ⅲ or Ⅳ soft roofs are the most dangerous areas where gas outburst most likely can take place.Therefore, countermeasures should be taken in these areas to prevent gas outbursts.

  4. Capture and release of acid-gasses with acid-gas binding organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Heldebrant, David J; Yonker, Clement R; Koech, Phillip K

    2015-03-17

    A system and method for acid-gas capture wherein organic acid-gas capture materials form hetero-atom analogs of alkyl-carbonate when contacted with an acid gas. These organic-acid gas capture materials include combinations of a weak acid and a base, or zwitterionic liquids. This invention allows for reversible acid-gas binding to these organic binding materials thus allowing for the capture and release of one or more acid gases. These acid-gas binding organic compounds can be regenerated to release the captured acid gasses and enable these organic acid-gas binding materials to be reused. This enables transport of the liquid capture compounds and the release of the acid gases from the organic liquid with significant energy savings compared to current aqueous systems.

  5. Mixed solvent system for treating acidic gas

    Energy Technology Data Exchange (ETDEWEB)

    Capobianco, P.J.; Butwell, K.F.; Kossakowski, E.J.

    1987-11-10

    This invention discloses mixtures of alkyl dialcohol amines and mono alkyl ethers of polyethylene glycols which are useful in removing acidic gases from gaseous mixtures. The solvent mixtures contain between 1.5 N and 5.0 N methyl diethanolamine (MDEA), 10 to 40 percent water and the balance is methoxytriglycol (MTG). The overall heat of reaction of the solution is typically less than 500 BTU/lb CO/sub 2/, and remains as a single liquid phase during normal gas scrubber operating conditions.

  6. Evaluation of membrane processes for acid gas treatment

    NARCIS (Netherlands)

    Jahn, J.; Bos, W.A.P. van den; Broeke, L.J.P. van den

    2012-01-01

    An overview is given of different membrane processes that are used for acid gas removal from natural gas. The main characteristics of selective membranes and membrane contactors for gas separation involving mixtures with acid gases are discussed. The removal of carbon dioxide from gaseous streams an

  7. Using Willie's Acid-Base Box for Blood Gas Analysis

    Science.gov (United States)

    Dietz, John R.

    2011-01-01

    In this article, the author describes a method developed by Dr. William T. Lipscomb for teaching blood gas analysis of acid-base status and provides three examples using Willie's acid-base box. Willie's acid-base box is constructed using three of the parameters of standard arterial blood gas analysis: (1) pH; (2) bicarbonate; and (3) CO[subscript…

  8. Validation of acid washes as critical control points in hazard analysis and critical control point systems.

    Science.gov (United States)

    Dormedy, E S; Brashears, M M; Cutter, C N; Burson, D E

    2000-12-01

    A 2% lactic acid wash used in a large meat-processing facility was validated as an effective critical control point (CCP) in a hazard analysis and critical control point (HACCP) plan. We examined the microbial profiles of beef carcasses before the acid wash, beef carcasses immediately after the acid wash, beef carcasses 24 h after the acid wash, beef subprimal cuts from the acid-washed carcasses, and on ground beef made from acid-washed carcasses. Total mesophilic, psychrotrophic, coliforms, generic Escherichia coli, lactic acid bacteria, pseudomonads, and acid-tolerant microorganisms were enumerated on all samples. The presence of Salmonella spp. was also determined. Acid washing significantly reduced all counts except for pseudomonads that were present at very low numbers before acid washing. All other counts continued to stay significantly lower (P HACCP plans and can significantly reduce the total number of microorganisms present on the carcass and during further processing.

  9. Herbs and hazards: risk of aristolochic acid nephropathy in Iran.

    Science.gov (United States)

    Ardalan, Mohammad Reza; Khodaie, Laleh; Nasri, Hamid; Jouyban, Abolghasem

    2015-01-01

    Herbs are usually considered as inherently harmless products. Nonetheless, various renal injuries have been reported in association with several herbs. The best-known herb-induced chronic kidney disease is aristolochic acid nephropathy. Aristolochic acid is found in Chinese slim herbs. Balkan endemic nephropathy is nowadays considered as an aristolochic acid nephropathy. Plants of Aristolochiaceae (also known as birthwort, dutchman's pipe, and somersworth) is named zaravand or chopoghak in Persian and it grows in different mountainous and rural areas of Iran. The fruit and the steam of the Aristolochiacae are named zaravand gerd (nokhod alvand) and zaravand dearaz, respectively, and have different usage in Iranian teadirional such as treatment of headache, back pain, and anxiety. Some patients with end-stage renal disease and bilateral small kidneys have a history of exposure to some herbal remedies. We need to consider the possibility of environmental toxins and even Aristolochia nephrotoxicity as a potential danger in Iran.

  10. Development of an Intelligent Hypertext Manual for the Space Shuttle Hazardous Gas Detection System

    Science.gov (United States)

    Lo, Ching F.; Shi, George Z.; Overbey, Glenn; Bangasser, Carl; Cegielski, Eric

    1992-01-01

    The Intelligent Hypertext Manual (IHM) for the Hazardous Gas Detection System (HGDS) of the Space Shuttle is described as an example of an integrated knowledge system. The IHM is described in terms of its design as a system for facilitating the interpretation of real-time data regarding hazardous gases and their successful and timely detection. Hypermedia technology is employed that incorporates text, video, and sound, and the architecture of the IHM integrated knowledge system is based on knowledge elements, a basic user interface, and integrated application software. Knowledge organization enhances the retrieval of documents for launch commit criteria, operations and maintenance requirements, flight-measurement location, and hypermedia incorporation. The integration of computer and AI technologies for the HGDS IHM demonstrates the potential for enhancing efficiency in aerospace operations with aerospace data that are easy to retrieve.

  11. Equilibrium water content measurements for acid gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, R.A.; Fitzpatrick, E.; Bernard, F.; Wan, H.H.; Lesage, K.L.; Davis, P.M.; Clark, P.D. [Alberta Sulphur Research Ltd., Calgary, AB (Canada)

    2009-07-01

    An accurate understanding of acid gas and water equilibrium is needed in order to design safe acid gas injection facilities. This paper described a joint industry project conducted to measure the water content of acid gas mixtures under moderate pressures and temperatures. The study has accumulated over 160 data points. Techniques used to obtain the measurements have included visual dew point determination for liquid acid gas and hydrates; the equilibration of samples in stirred autoclaves; basic static equilibration cells; and an isolated floating piston with a micro-sampler used to inject gaseous and liquid acid gas phases. As a result of the project, a high pressure micro-sampling technique has been developed to pressure limits of 1000 bar. 33 refs., 2 tabs., 10 figs.

  12. Acid sulfate soils are an environmental hazard in Finland

    Science.gov (United States)

    Pihlaja, Jouni

    2016-04-01

    Acid sulfate soils (ASS) create significant threats to the environment on coastal regions of the Baltic Sea in Finland. The sediments were deposited during the ancient Litorina Sea phase of the Baltic Sea about 7500-4500 years ago. Finland has larger spatial extent of the ASS than any other European country. Mostly based on anthropogenic reasons (cultivation, trenching etc.) ASS deposits are currently being exposed to oxygen which leads to chemical reaction creating sulfuric acid. The acidic waters then dissolve metals form the soil. Acidic surface run off including the metals are then leached into the water bodies weakening the water quality and killing fish or vegetation. In constructed areas acidic waters may corrode building materials. Geological Survey of Finland (GTK) is mapping ASS deposits in Finland. The goal is to map a total of 5 million hectares of the potentially ASS affected region. It has been estimated that the problematic Litorina Sea deposits, which are situated 0-100 m above the recent Baltic Sea shoreline, cover 500 000 hectares area. There are several phases in mapping. The work begins at the office with gathering the existing data, interpreting airborne geophysical data and compiling a field working plan. In the field, quality of the soil is studied and in uncertain cases samples are taken to laboratory analyses. Also electrical conductivity and pH of soil and water are measured in the field. Laboratory methods include multielemental determinations with ICP-OES, analyses of grain size and humus content (LOI), and incubation. So far, approximately 60 % of the potential ASS affected regions in Finland are mapped. Over 15 000 sites have been studied in the field and 4000 laboratory analyses are done. The spatial database presented in the scale of 1: 250 000 can be viewed at the GTK's web pages (http://gtkdata.gtk.fi/hasu/index.html).

  13. Intelligent hypertext manual development for the Space Shuttle hazardous gas detection system

    Science.gov (United States)

    Lo, Ching F.; Hoyt, W. Andes

    1989-01-01

    This research is designed to utilize artificial intelligence (AI) technology to increase the efficiency of personnel involved with monitoring the space shuttle hazardous gas detection systems at the Marshall Space Flight Center. The objective is to create a computerized service manual in the form of a hypertext and expert system which stores experts' knowledge and experience. The resulting Intelligent Manual will assist the user in interpreting data timely, in identifying possible faults, in locating the applicable documentation efficiently, in training inexperienced personnel effectively, and updating the manual frequently as required.

  14. Possible hazardous effects of hydrofluoric acid and recommendations for treatment approach : a review

    NARCIS (Netherlands)

    Allahbeickaraghi, Arezo; Dundar, Mine; Ozcan, Mutlu

    2012-01-01

    Hydrofluoric acid (HF) is commonly used for conditioning the glass ceramics either prior to cementation or for intraoral repair in prosthetic and restorative dentistry. The present study offers a review of chemical properties of HF used, highlight the possible hazardous effects of this agent, and to

  15. The Role of Deposition in Limiting the Hazard Extent of Dense-Gas Plumes

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, M B

    2008-05-11

    Accidents that involve large (multi-ton) releases of toxic industrial chemicals and form dense-gas clouds often yield far fewer fatalities, casualties and environmental effects than standard assessment and emergency response models predict. This modeling study, which considers both dense-gas turbulence suppression and deposition to environmental objects (e.g. buildings), demonstrates that dry deposition to environmental objects may play a significant role in reducing the distance at which adverse impacts occur - particularly under low-wind, stable atmospheric conditions which are often considered to be the worst-case scenario for these types of releases. The degree to which the released chemical sticks to (or reacts with) environmental surfaces is likely a key parameter controlling hazard extents. In all modeled cases, the deposition to vertical surfaces of environmental objects (e.g. building walls) was more efficient in reducing atmospheric chemical concentrations than deposition to the earth's surface. This study suggests that (1) hazard extents may vary widely by release environment (e.g. grasslands vs. suburbia) and release conditions (e.g. sunlight or humidity may change the rate at which chemicals react with a surface) and (2) greenbelts (or similar structures) may dramatically reduce the impacts of large-scale releases. While these results are demonstrated to be qualitatively consistent with the downwind extent of vegetation damage in two chlorine releases, critical knowledge gaps exist and this study provides recommendations for additional experimental studies.

  16. Evaluation of radiation hazard potential of TENORM waste from oil and natural gas production.

    Science.gov (United States)

    Hilal, M A; Attallah, M F; Mohamed, Gehan Y; Fayez-Hassan, M

    2014-10-01

    In this study, a potential radiation hazard from TENORM sludge wastes generated during exploration and extraction processes of oil and gas was evaluated. The activity concentration of natural radionuclides (238)U, (226)Ra and (232)Th were determined in TENORM sludge waste. It was found that sludge waste from oil and gas industry is one of the major sources of (226)Ra in the environment. Therefore, some preliminary chemical treatment of sludge waste using Triton X-100 was also investigated to reduce the radioactivity content as well as the risk of radiation hazard from TENORM wastes. The activity concentrations of (226)Ra and (228)Ra in petroleum sludge materials before and after chemical treatment were measured using gamma-ray spectrometry. The average values of the activity concentrations of (226)Ra and (228)Ra measured in the original samples were found as 8908 Bq kg(-1) and 933 Bq kg(-1), respectively. After chemical treatment of TENORM samples, the average values of the activity concentrations of (226)Ra and (228)Ra measured in the samples were found as 7835 Bq kg(-1) and 574 Bq kg(-1), respectively. Activity concentration index, internal index, absorbed gamma dose rate and the corresponding effective dose rate were estimated for untreated and treated samples.

  17. The spatiotemporal characteristics of environmental hazards caused by offshore oil and gas operations in the Gulf of Mexico.

    Science.gov (United States)

    Meng, Qingmin

    2016-09-15

    Marine ecosystems are home to a host of numerous species ranging from tiny planktonic organisms, fishes, and birds, to large mammals such as the whales, manatees, and seals. However, human activities such as offshore oil and gas operations increasingly threaten marine and coastal ecosystems, for which there has been little exploration into the spatial and temporal risks of offshore oil operations. Using the Gulf of Mexico, one of the world's hottest spots of offshore oil and gas mining, as the study area, we propose a spatiotemporal approach that integrates spatial statistics and geostatistics in a geographic information system environment to provide insight to environmental management and decision making for oil and gas operators, coastal communities, local governments, and the federal government. We use the records from 1995 to 2015 of twelve types of hazards caused by offshore oil and gas operations, and analyze them spatially over a five year period. The spatial clusters of these hazards are analyzed and mapped using Getis-Ord Gi and local Moran's I statistics. We then design a spatial correlation coefficient matrix for multivariate spatial correlation, which is the ratio of the cross variogram of two types of hazards to the product of the variograms of the two hazards, showing a primary understanding of the degrees of spatial correlation among the twelve types hazards. To the best of our knowledge, it is the first application of spatiotemporal analysis methods to environmental hazards caused by offshore oil and gas operations; the proposed methods can be applied to other regions for the management and monitoring of environmental hazards caused by offshore oil operations.

  18. Possible hazardous effects of hydrofluoric acid and recommendations for treatment approach: a review.

    Science.gov (United States)

    Ozcan, Mutlu; Allahbeickaraghi, Arezo; Dündar, Mine

    2012-02-01

    Hydrofluoric acid (HF) is commonly used for conditioning the glass ceramics either prior to cementation or for intraoral repair in prosthetic and restorative dentistry. The present study offers a review of chemical properties of HF used, highlight the possible hazardous effects of this agent, and to recommend the treatment approach for potential risks. Available published information documented in PubMed, Medline, and Picarta literature databases was reviewed. Additional information was derived from scientific reports, medical and chemical textbooks, handbooks, product information, manufacturers' instructions, Internet web sites of the HF manufacturers. No report was found on the incidence of the hazardous effects of HF in dentistry. Reports from other fields presented incidences of acute and chronic symptoms in exposure to HF. While acute symptoms include skin or nail burns, chronic ones involve systemic toxicity, eye injuries, inhalation and ingestion-related symptoms that can be even fatal. HF can be harmful and particularly aggressive to soft tissues, but symptoms may not be apparent immediately after exposure. The hazardous effects are not based on the pH value, but on the toxicity of HF. Potential hazards of HF known from other applications than dentistry should be considered also in dental applications. Especially the clinicians, who often deal with adhesive cementation or repair of glass ceramics, should take necessary precautions for possible hazards of HF.

  19. Coal seam gas water: potential hazards and exposure pathways in Queensland.

    Science.gov (United States)

    Navi, Maryam; Skelly, Chris; Taulis, Mauricio; Nasiri, Shahram

    2015-01-01

    The extraction of coal seam gas (CSG) produces large volumes of potentially contaminated water. It has raised concerns about the environmental health impacts of the co-produced CSG water. In this paper, we review CSG water contaminants and their potential health effects in the context of exposure pathways in Queensland's CSG basins. The hazardous substances associated with CSG water in Queensland include fluoride, boron, lead and benzene. The exposure pathways for CSG water are (1) water used for municipal purposes; (2) recreational water activities in rivers; (3) occupational exposures; (4) water extracted from contaminated aquifers; and (5) indirect exposure through the food chain. We recommend mapping of exposure pathways into communities in CSG regions to determine the potentially exposed populations in Queensland. Future efforts to monitor chemicals of concern and consolidate them into a central database will build the necessary capability to undertake a much needed environmental health impact assessment.

  20. Control of gas hazards in coal mines with the help of bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska-Lipowa, W.

    1979-06-01

    The physiology and biochemical activity of bacteria participating in formation and oxidation of methane in coal seams and in the bottom of water basins are discussed. Microbiological research shows the possibility of using bacteria for fighting gas hazards. The only institution in Poland conducting research in this field is the Institute of Mining Techniques of Deposits, Mining Department of the Silesia Polytechnic Institute. The Institute collected about 200 samples of water from coal mines in Silesia, Slovakia and from the Mazurian Lakes. It was proved that in some of the samples there are bacteria utilizing methane as the only source of carbon. In the laboratories of the Institute some cultures of bacteria living on methane were produced. Soviet scientists have maintained that the use of bacteria utilizing carbon dioxide and methane can reduce the content of these gases in coal mine air by 30-40%.

  1. Determination of Fatty Acid in Asparagus by Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Zehra HAJRULAI-MUSLIU

    2016-05-01

    Full Text Available Asparagus contain a lot of macronutrients and micronutrients including folate, dietary fibre (soluble and insoluble and phenolic compounds. Also asparagus is a good source of unsaturated linoleic and linolenic fatty acids which are precursors for Eicosapentanoic acid (EPA and Docosahexanoic acid (DHA. Unsaturated fatty acids have important biological effects and they have important role in human health. The objective of this study was to analyze fatty acid composition of asparagus as a potential source of linoleic and linolenic acid - a precursor for EPA and DHA. For this reason we analyzed fifty seven samples of asparagus collected from the local market. We used AOAC 996.06 method and analyses were performed with gas chromatograph with flame-ionization detector (GC-FID. The highest concentration of fatty acid in the asparagus was linoleic acid (C18:2n6 which content in asparagus is 25.620±1.0%. Also, asparagus is good source of -linolenic fatty acid (C18:3n3 and content of this fatty acid in asparagus is 8.840±0.3%. The omega-6 to omega-3 (n6/n3 ratio in asparagus was 3.19. Polyunsaturated fatty acids (PUFAs were higher than monounsaturated fatty acids (MUFAs, and from saturated fatty acids, palmitic acid was most frequent with 24.324±1.0%. From our study we can conclude that asparagus is very good source of unsaturated fatty acids, especially linoleic and linolenic fatty acids.

  2. Forecasting the degree of rock burst hazard in areas of gas bearing coal seams by the electromagnetic radiation method

    Energy Technology Data Exchange (ETDEWEB)

    Proskuryakov, V.M.; Shabarov, A.N.; Frid, V.I. (Vsesoyuznyi Nauchno-Issledovatel' skii Institut Gornoi Geomekhaniki i Marksheiderskogo Dela (USSR))

    1991-02-01

    Presents results of investigations into emission of electromagnetic waves in zones of increased rock burst hazard conducted during drivage of a ventilation gallery in the Anzherskaya mine (Severokuzbassugol' association). Relationships between the emission of electromagnetic impulses, yield of drilling, gas yield rate, the distance between increased stress zones and seam denudation and time are discussed and presented in diagrams. Regularities of variation in electromagnetic radiation at various stress states in coal seam boundary parts with the gas yield factor taken into account were found. Suitability of recording electromagnetic radiation for forecasting rock burst hazards was shown and criteria for evaluating the degree of rock burst hazard for a coal seam in the Anzherskaya mine are presented. 3 refs.

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

    Science.gov (United States)

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

    2016-01-01

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

  4. Capillary gas-chromatographic determination of urinary homovanillic acid and vanillylmandelic acid.

    Science.gov (United States)

    Tuchman, M; Crippin, P J; Krivit, W

    1983-05-01

    This relatively simple, rapid method for quantification of homovanillic acid (HVA) and vanillylmandelic acid (VMA) involves solvent extraction and capillary gas chromatography. With use of this extraction method, the overall analytical recovery from an aqueous solution is 92.5% for HVA and 79.2% for VMA. 3,4-Dihydroxybenzoic acid is the internal standard. Minimal detectable quantities with this method are less than 1 mg/g of creatinine. Capillary gas chromatography produces a chromatogram that is superior to that of packed-column gas chromatography. We also report quantitative results for urinary HVA and VMA in neuroblastoma patients and in normal individuals, demonstrating the diagnostic value of this method.

  5. Role of tectonic movements in the origin of gas outburst hazards of black coal seams in the Mecsek Area

    Energy Technology Data Exchange (ETDEWEB)

    Nemedi; Varga, Z.

    1985-01-01

    The tectonics and the major structural elements of the lower Liassic black coal seams of the Mecsek Area are reviewed. The folded and faulted tectonic elements play a predominant role in the process of gas migration and trap formation. Since these elements are of primary importance from the point of view of gas outburst hazard, the knowledge of the distribution and peculiarities of these elements is very important. The investigations needed to forecast the gas outbursts both from the local and from the areal point of view are comprehensively discussed.

  6. Regional differences in the variations of the degree of gas outburst hazard for Mecsek sub-bituminous coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Nemedi Varga, Z.

    1987-01-01

    In the collieries of the Mecsek Mountains (South Hungary) in which the sub-bituminous coal is exploited, coal and gas outbursts as well as gas outbursts have been recorded in the Pecs-area since 1984, in the Szaszvar area since 1902, and nowadays in the Komlo-area since 1964. Concerning the degree of gas outbursts hazard, the differences between the Pecs and Komlo areas cannot be explained by the differences in facies, by structural differences and by the frequency of occurrence of igneous rocks. The conditions of coalification seem to be responsible for these differences. In this respect the significance of the so-called second phase coalification is emphasized.

  7. Feedlot lamb meat fatty acids profile characterization employing gas chromatography

    Directory of Open Access Journals (Sweden)

    M.I. Cruz-Gonzalez

    2014-06-01

    Full Text Available Fat is an important constituent in diet, not only as an energy source, but for its essential fatty acids associated to fats in foods, considering that some polyunsaturated fatty acids like linoleic, linolenic and arachidonic cannot be synthesized by superior animals like humans. Scientific evidence show that the fatty acids ingest can affect the thrombotic tendency, cardiac rhythm, endothelial function systematic inflammation, insulin sensibility and oxidative stress. Samples from 21 ovine crossbreds from Pelibuey, Blackbelly, Dorper and Katahadin (40 kg average weight feed with corn based balanced diets were taken from loin area 18 h after refrigeration. Saturated and polyunsaturated fatty acids levels were analyzed by gas chromatography. Results in this work showed that the healthy fatty acids levels are higher as compared to saturated fatty acids levels, indicating that this meat can influence consumer’s buying choice decision regarded to their health.

  8. Seven Conformers of Pipecolic Acid Identified in the Gas Phase

    Science.gov (United States)

    Cabezas, Carlos; Simao, Alcides; Alonso, José L.

    2016-06-01

    The multiconformational landscape of the non-proteinogenic cyclic amino acid pipecolic acid has been explored in the gas phase. Solid pipecolic acid (m.p. 280°C) was vaporized by laser ablation (LA) and expanded in a supersonic jet where the rotational spectra of seven conformers were obtained by broadband microwave spectroscopy (CP-FTMW). All conformers were conclusively identified by comparison of the experimental spectroscopic constants with those predicted theoretically. The relative stability of the conformers rests on a delicate balance of the different intramolecular hydrogen bonds established between the carboxylic and the amino groups.

  9. Study on Cyclometalated Palladium-azo Complexes as Colorimetric Probes for Hazardous Gas in Water

    Institute of Scientific and Technical Information of China (English)

    YU,Chun-Wei; LI,Shun-Hua; ZHENG,Hong; XU,Jin-Gou

    2007-01-01

    A synthesized cyclometalated palladium-azo complex was explored as a multifunctional probe for visual detection of SO2, H2S and NH3 in water. In acidic aqueous environment, the sensing solution underwent a sharp color change from poor violet to deep blue when titrated with Na2SO3 standard solution. But the color changed from poor violet to bright yellow when titrated with Na2S standard solution. In basic environment, the sensing solution rapidly changed to magenta when titrated by NH4Cl-NH3 standard buffer solution at high concentration. However, the color of sensing solution changed to blue when titrated by NH4Cl-NH3 standard buffer solution at low concentration although the pH was kept constant during the titration. Different species of these hazardous gases at environmentally relevant concentration levels were differentiated by independent optical signal outputs, and the interference from other inorganic ions commonly existing in water was very small.

  10. The risk early-warning of gas hazard in coal mine based on Rough Set-neural network

    Institute of Scientific and Technical Information of China (English)

    TIAN Shui-cheng; WANG Li

    2007-01-01

    This article proposed the risk early-warning model of gas hazard based on Rough Set and neural network. The attribute quantity was reduced by Rough Set, the main characteristic attributes were withdrawn, the complexity of neural network system and the computing time was reduced, as well. Because of fault-tolerant ability, parallel processing ability, anti-jamming ability and processing non-linear problem ability of neural network system, the methods of Rough Set and neural network were combined. The examples research indicate: applying Rough Set and BP neural network to the gas hazard risk early-warning coal mines in coal mine, the BPNN structure is greatly simplified, the network computation quantity is reduced and the convergence rate is speed up.

  11. Modeling acid-gas generation from boiling chloride brines

    Directory of Open Access Journals (Sweden)

    Sonnenthal Eric

    2009-11-01

    Full Text Available Abstract Background This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Results Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150°C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. Conclusion The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual

  12. White Paper on Potential Hazards Associated with Contaminated Cheesecloth Exposed to Nitric Acid Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Hypes, Philip A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-20

    This white paper addresses the potential hazards associated with waste cheesecloth that has been exposed to nitric acid solutions. This issue was highlighted by the cleanup of a 100 ml leak of aqueous nitric acid solution containing Heat Source (HS) plutonium on 21 June 2016. Nitration of cellulosic material is a well-understood process due to industrial/military applications of the resulting material. Within the Department of Energy complex, nitric acids have been used extensively, as have cellulosic wipes. If cellulosic materials are nitrated, the cellulosic material can become ignitable and in extreme cases, reactive. We have chemistry knowledge and operating experience to support the conclusion that all current wastes are safe and compliant. There are technical questions worthy of further experimental evaluation. An extent of condition evaluation has been conducted back to 2004. During this time period there have been interruptions in the authorization to use cellulosic wipes in PF-4. Limited use has been authorized since 2007 (for purposes other than spill cleanup), so our extent of condition includes the entire current span of use. Our evaluation shows that there is no indication that process spills involving high molarity nitric acid were cleaned up with cheesecloth since 2007. The materials generated in the 21 June leak will be managed in a safe manner compliant with all applicable requirements.

  13. Fatty acids determination in Bronte pistachios by gas chromatographic method.

    Science.gov (United States)

    Pantano, Licia; Lo Cascio, Giovanni; Alongi, Angelina; Cammilleri, Gaetano; Vella, Antonio; Macaluso, Andrea; Cicero, Nicola; Migliazzo, Aldo; Ferrantelli, Vincenzo

    2016-10-01

    A gas chromatographic with flame ionization detector (GC-MS FID) method for the identification and quantification of fatty acids based on the extraction of lipids and derivatisation of free acids to form methyl esters was developed and validated. The proposed method was evaluated to a number of standard FAs, and Bronte pistachios samples were used for that purpose and to demonstrate the applicability of the proposed method. In this regard, repeatability, mean and standard deviation of the analytical procedure were calculated. The results obtained have demonstrated oleic acid as the main component of Bronte pistachios (72.2%) followed by linoleic acid (13.4%) and showed some differences in composition with respect to Tunisian, Turkish and Iranian pistachios.

  14. Estimation of brassylic acid by gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed J. Nasrullah, Erica N. Pfarr, Pooja Thapliyal, Nicholas S. Dusek, Kristofer L. Schiele, Christy Gallagher-Lein, and James A. Bahr

    2010-10-29

    The main focus of this work is to estimate Brassylic Acid (BA) using gas chromatography-mass spectrometry (GC-MS). BA is a product obtained from the oxidative cleavage of Erucic Acid (EA). BA has various applications for making nylons and high performance polymers. BA is a 13 carbon compound with two carboxylic acid functional groups at the terminal end. BA has a long hydrocarbon chain that makes the molecule less sensitive to some of the characterization techniques. Although BA can be characterized by NMR, both the starting material (EA) and products BA and nonanoic acid (NA) have peaks at similar {delta}, ppm values. Hence it becomes difficult for the quick estimation of BA during its synthesis.

  15. Report: Proceedings of the Hedberg Research Conference 'Gas Hydrates : Energy resource potential and associated geologic hazards'

    Digital Repository Service at National Institute of Oceanography (India)

    Veerayya, M.

    Resources Development Research' discussed the results of drilling for methane hydrate evaluation in the Nankai Trough; coring in the Gulf of Mexico; the lessons learned from the past three decades of Gas Hydrate exploration at the Mallik Gas Hydrate Field... along the Norwegian Margin. An exclusive Session was devoted to Gas Hydrate investigations in the Gulf of Mexico. The Session on 'Resource Potential and Geology of Terrestrial Arctic Gas Hydrates* covered topics viz., Prospecting for Gas Hydrates...

  16. Determining the explosion risk level and the explosion hazard area for a group of natural gas wells

    Science.gov (United States)

    Gligor, A.; Petrescu, V.; Deac, C.; Bibu, M.

    2016-11-01

    Starting from the fact that the natural gas engineering profession is generally associated with a high occupational risk, the current paper aims to help increase the safety of natural gas wells and reduce the risk of work-related accidents, as well as the occurrence of professional illnesses, by applying an assessment method that has proven its efficiency in other industrial areas in combination with a computer-aided design software. More specifically, the paper focuses on two main research directions: assessing the explosion risk for employees working at natural gas wells and indicating areas with a higher explosion hazard by using a modern software that allows their presentation in 3D. The appropriate zoning of industrial areas allows to group the various functional areas function of the probability of the occurrence of a dangerous element, such as an explosive atmosphere and subsequently it allows also to correctly select the electrical and mechanical equipment that will be used in that area, since electrical apparatuses that are otherwise found in normal work environments cannot generally be used in areas with explosion hazard, because of the risk that an electric spark, an electrostatic discharge etc. ignites the explosive atmosphere.

  17. Gas-phase acid-base properties of melamine and cyanuric acid.

    Science.gov (United States)

    Mukherjee, Sumit; Ren, Jianhua

    2010-10-01

    The thermochemical properties of melamine and cyanuric acid were characterized using mass spectrometry measurements along with computational studies. A triple-quadrupole mass spectrometer was employed with the application of the extended Cooks kinetic method. The proton affinity (PA), gas-phase basicity (GB), and protonation entropy (Δ(p)S) of melamine were determined to be 226.2 ± 2.0 kcal/mol, 218.4 ± 2.0 kcal/mol, and 26.2 ± 2.0 cal/mol K, respectively. The deprotonation enthalpy (Δ(acid)H), gas-phase acidity (Δ(acid)G), and deprotonation entropy (Δ(acid)S) of cyanuric acid were determined to be 330.7 ± 2.0 kcal/mol, 322.9 ± 2.0 kcal/mol, and 26.1 ± 2.0 cal/mol K, respectively. The geometries and energetics of melamine, cyanuric acid, and related ionic species were calculated at the B3LYP/6-31+G(d) level of theory. The computationally predicted proton affinity of melamine (225.9 kcal/mol) and gas-phase deprotonation enthalpy of cyanuric acid (328.4 kcal/mol) agree well with the experimental results. Melamine is best represented as the imide-like triazine-triamine form and the triazine nitrogen is more basic than the amino group nitrogen. Cyanuric acid is best represented as the keto-like tautomer and the N-H group is the most probable proton donor.

  18. Health hazards and disaster potential of ground gas emissions at Furnas volcano, São Miguel, Azores

    Science.gov (United States)

    Baxter, Peter J.; Baubron, Jean-Claude; Coutinho, Rui

    1999-09-01

    A health hazard assessment of exposure to soil gases (carbon dioxide and radon) was undertaken in the village of Furnas, located in the caldera of an active volcano. A soil survey to map the area of soil gas flow was undertaken, gas emissions were monitored at fumaroles and in eight houses, and a preliminary radon survey of 23 houses in the main anomaly area was performed. Potential volcanic sources of toxic contamination of air, food, and water were also investigated, and ambient air quality was evaluated. About one-third (41 ha) of the houses were located in areas of elevated carbon dioxide soil degassing. Unventilated, confined spaces in some houses contained levels of carbon dioxide which could cause asphyxiation. Mean indoor radon levels exceeded UK and US action levels in the winter months. A tenfold increase in radon levels in one house over 2 h indicated that large and potentially lethal surges of carbon dioxide could occur without warning. Toxic exposures from the gaseous emissions and from contamination of soil and water were minimal, but sulphur dioxide levels were mildly elevated close to fumaroles. In contrast, evidence of dental fluorosis was manifested in the population of the nearby fishing village of Ribeira Quente where drinking water in the past had contained elevated levels of fluoride. The disaster potential of volcanic carbon dioxide in the area could also be associated with the hydrothermal system storing dissolved carbon dioxide beneath the village. Felt, or unfelt, seismic activity, or magma unrest, especially with a reawakening of explosive volcanic activity (30% probability in the next 100 years) could result in an increase in gas flow or even a gas burst from the hydrothermal system. A survey of all houses in Furnas is advised as structural measures to prevent the ingress of soil gases, including radon, were needed in some of the study houses. Evaluations of the human hazards of volcanic gases should be undertaken in all settlements in

  19. Measurement of Gas-phase Acids in Diesel Exhaust

    Science.gov (United States)

    Wentzell, J. J.; Liggio, J.; Li, S.; Vlasenko, A. L.; Staebler, R. M.; Brook, J.; Lu, G.; Poitras, M.; Chan, T.

    2012-12-01

    Gas-phase acids were measured using chemical ionization mass spectrometry (CIMS) as part of the Diesel Engine Emission Research Experiment (DEERE). The CIMS technique, utilizing acetate ion (CH3COO-) as a reagent ion, proved to be a rapid (measurements on the order of seconds) and sensitive (several counts/pptv) method of quantifying the acid emissions. Diluted diesel exhaust measurements were made from a Constant Volume Sampling dilution tunnel using a light duty (1.9L turbocharged Volkswagen Jetta TDI) diesel engine equipped with an OEM diesel oxidation catalyst and exhaust gas recirculation, mounted on an engine dynamometer. Acids measured included isocyanic, nitrous, nitric, propionic and sum of lactic and oxalic, as well as other unidentified compounds. Complimentary measurements of CO, CO2, Total Hydrocarbon (THC), and NOx, were also performed. Several engine modes (different engine rpm and torque outputs) at steady state were examined to determine their effect on acid emissions. Emission rates with respect to NOx and fuel based emission factors were determined. Measurements of HONO fuel emission factors agree well with real-world measurements within a traffic tunnel.1 The first estimate of isocyanic acid emission factors from a diesel engine is reported, and suggests that the emission of this highly toxic compound in diesel exhaust should not be ignored. 1. Kurtenbach, R., Becker, K. H., Gomes, J. A. G., Kleffmann, J.,Lorzer, J. C., Spittler, M., Wiesen, P., Ackermann, R., Geyer, A.,and Platt, U.: Investigations of emissions and heterogeneous formation of HONO in a road traffic tunnel, Atmos. Environ., 35, 3385-3394, doi:10.1016/S1352-2310(01)00138-8, 2001.

  20. CHRIS: Hazard Assessment Handbook

    Science.gov (United States)

    1977-12-12

    CODE AIJ 91 HAZARD ASSESSMENT CODE-ABC KLMN 95 A. VENTING GAS FIRE -CODE AB 97 B. LIOUID FIRE-CODE AKL 97 C. WATER POLLUTION HAZARDS - CODE AK 99 D...The Hazard Calculation Codes for liquefied natural gas are: AB — venting gas fire . AC - gas dispersion, ADE — liquid fire, and ADFG...5.4). Spill Amount Wind Velocity Wind Direction Weather ppm tons knots Primary Code ABCKLMN Code AB - Venting Gas Fire Assessment

  1. Comments on Potential Geologic and Seismic Hazards Affecting Proposed Liquefied Natural Gas Site in Santa Monica Bay, California

    Science.gov (United States)

    Ross, Stephanie L.; Lee, Homa J.; Parsons, Tom E.; Beyer, Larry A.; Boore, David M.; Conrad, James E.; Edwards, Brian D.; Fisher, Michael A.; Frankel, Arthur D.; Geist, Eric L.; Hudnut, Kenneth W.; Hough, Susan E.; Kayen, Robert E.; Lorenson, T.D.; Luco, Nicolas; McCrory, Patricia A.; McGann, Mary; Nathenson, Manuel; Nolan, Michael; Petersen, Mark D.; Ponti, Daniel J.; Powell, Charles L.; Ryan, Holly F.; Tinsley, John C.; Wills, Chris J.; Wong, Florence L.; Xu, Jingping

    2008-01-01

    In a letter to the U.S. Geological Survey (USGS) dated March 25, 2008, Representative Jane Harman (California 36th district) requested advice on geologic hazards that should be considered in the review of a proposed liquefied natural gas (LNG) facility off the California coast in Santa Monica Bay. In 2004, the USGS responded to a similar request from Representative Lois Capps, regarding two proposed LNG facilities offshore Ventura County, Calif., with a report summarizing potential geologic and seismic hazards (Ross and others, 2004). The proposed LNG Deepwater Port (DWP) facility includes single point moorings (SPMs) and 35 miles of underwater pipelines. The DWP submersible buoys, manifolds, and risers would be situated on the floor of the southern Santa Monica Basin, in 3,000 feet of water, about 23 miles offshore of the Palos Verdes Peninsula. Twin 24-inch diameter pipelines would extend northeastward from the buoys across the basin floor, up the basin slope and across the continental shelf, skirting north around the Santa Monica submarine canyon. Figure 1 provides locations of the project and geologic features. Acronyms are defined in table 1. This facility is being proposed in a region of known geologic hazards that arise from both the potential for strong earthquakes and geologic processes related to sediment transport and accumulation in the offshore environment. The probability of a damaging earthquake (considered here as magnitude 6.5 or greater) in the next 30 years within about 30 miles (50 km) of the proposed pipeline ranges from 16% at the pipeline's offshore end to 48% where it nears land (Petersen, 2008). Earthquakes of this magnitude are capable of producing strong shaking, surface fault offsets, liquefaction phenomena, landslides, underwater turbidity currents and debris flow avalanches, and tsunamis. As part of the DWP license application for the Woodside Natural Gas proposal in Santa Monica Bay (known as the OceanWay Secure Energy Project), Fugro

  2. Corrosion in alkanolamine used for acid gas removal: From natural gas processing to CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Kittel, J.; Fleury, E.; Gonzalez, S.; Ropital, F. [IFP Energies nouvelles, Rond point de l' echangeur de Solaize, 69360 Solaize (France); Vuillemin, B.; Oltra, R. [Institut Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 21078 Dijon Cedex (France)

    2012-03-15

    The aim of this paper is to review some of the parameters influencing the corrosivity of alkanolamine solvents used for natural gas purification or for CO{sub 2} capture. In the light of literature data and of new experimental results, the influences of temperature and of acid gas loading are discussed. These two parameters appear to have a strong impact on corrosion rates of carbon steel, with extrapolated corrosion rates of several tens of mm/year for the highest temperature and acid gas loading condition. It is then proposed to discuss about similarities and differences between natural gas processing and CO{sub 2} capture from flue gas. For both applications, alkanolamine processes are used. Still, differences can be found in operating parameters. The most significant gap concerns the lean amine sections. In acid gas treatment, the regeneration of the solvent is often performed down to zero loading. Under these conditions, an extremely low corrosivity of the lean solvent is expected. On the contrary, CO{sub 2} capture from flue gas requires only a partial stripping of the CO{sub 2} in the regeneration section, due to energy efficiency reasons. Then, the lean solvent still contains some acid gas, and subsequently a higher corrosivity. Finally, the general principles for material selection for the different parts of acid gas removal units are discussed, considering both cases of natural gas processing or CO{sub 2} capture. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Simulation of a Wet Sulfuric Acid Process (WSA for Utilization of Acid Gas Separated from Omani Natural Gas

    Directory of Open Access Journals (Sweden)

    Ahmed Jawad Ali Al-Dallal

    2013-06-01

    Full Text Available In this study, a proposed process for the utilization of hydrogen sulphide separated with other gases from omani natural gas for the production of sulphuric acid by wet sulphuric acid process (WSA was studied. The processwas simulated at an acid gas feed flow of 5000 m3/hr using Aspen ONE- V7.1-HYSYS software. A sensitivity analysis was conducted to determine the optimum conditions for the operation of plant. This included primarily the threepacked bed reactors connected in series for the production of sulphur trioxidewhich represented the bottleneck of the process. The optimum feed temperature and catalyst bed volume for each reactor were estimated and then used in the simulation of the whole process for two cases namely 4 and 6 mole% SO2 stream fed to the first catalytic reactor. The 4mole% SO2 gaves the highest conversion (98% compared with 6 mole% SO2 (94.7%. A valuable quantity of heat was generated from the process. This excess heat could also be transformed into power in a turbine or used as a heating media in neighbouring process units.

  4. Amine-oxide hybrid materials for acid gas separations

    KAUST Repository

    Bollini, Praveen

    2011-01-01

    Organic-inorganic hybrid materials based on porous silica materials functionalized with amine-containing organic species are emerging as an important class of materials for the adsorptive separation of acid gases from dilute gas streams. In particular, these materials are being extensively studied for the adsorption of CO 2 from simulated flue gas streams, with an eye towards utilizing these materials as part of a post-combustion carbon capture process at large flue gas producing installations, such as coal-fired electricity-generating power plants. In this Application Article, the utilization of amine-modified organic-inorganic hybrid materials is discussed, focusing on important attributes of the materials, such as (i) CO 2 adsorption capacities, (ii) adsorption and desorption kinetics, and (iii) material stability, that will determine if these materials may one day be useful adsorbents in practical CO 2 capture applications. Specific research needs and limitations associated with the current body of work are identified. © 2011 The Royal Society of Chemistry.

  5. Wave propagation versus transient ground displacement as a credible hazard to buried oil and gas pipelines

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The cause of damage to a natural gas pipeline during the 1994 Northridge earthquake in the San Fernando Valley in California was examined in a collaborative effort by Southern California Gas Co., Pacific Gas and Electric Co., and with support from Tokyo Gas, Osaka Gas and Toho Gas. Extensive field and laboratory studies were conducted on a 1925 gas pipeline that suffered several girth weld failures in Potrero Canyon where significant ground displacement was observed. Ground cracking and sand boils were observed in the area following the earthquake but there were few other signs of permanent ground deformation near the pipeline damage. Damage consisted mostly of girth weld tensile failure and two cases of buckling of the pipe wall. Initial evidence suggested that the damage may have been caused by wave propagation, but a detailed study has shown that wave propagation effect was not a significant factor in the pipeline damage. A simple analytical model was developed to determine the transient ground deformation that might have occurred in the area of the pipeline damage. The model also provides clues regarding the cause of the ground cracking observed at the margins of the canyon. It also provides approximate magnitudes of differential ground displacements resulting from the earthquake. The model also considers the reasons for spatial distribution of pipeline damage. 13 refs., 1 tab., 6 figs.

  6. The Role of Deposition in Limiting the Hazard Extent of Dense-Gas Plumes

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, M B

    2008-01-29

    Accidents involving release of large (multi-ton) quantities of toxic industrial chemicals often yield far fewer fatalities and causalities than standard, widely-used assessment and emergency response models predict. While recent work has suggested that models should incorporate the protection provided by buildings, more refined health effect methodologies, and more detailed consideration of the release process; investigations into the role of deposition onto outdoor surfaces has been lacking. In this paper, we examine the conditions under which dry deposition may significantly reduce the extent of the downwind hazard zone. We provide theoretical arguments that in congested environments (e.g. suburbs, forests), deposition to vertical surfaces (such as building walls) may play a significant role in reducing the hazard zone extent--particularly under low-wind, stable atmospheric conditions which are often considered to be the worst-case scenario for these types of releases. Our analysis suggests that in these urban or suburban environments, the amount of toxic chemicals lost to earth's surface is typically a small fraction of overall depositional losses. For isothermal gases such as chlorine, the degree to which the chemicals stick to (or react with) surfaces (i.e. surface resistance) is demonstrated to be a key parameter controlling hazard extent (the maximum distance from the release at which hazards to human health are expected). This analysis does not consider the depositional effects associated with particulate matter or gases that undergo significant thermal change in the atmosphere. While no controlled experiments were available to validate our hypothesis, our analysis results are qualitatively consistent with the observed downwind extent of vegetation damage in two chlorine accidents.

  7. Capping hazardous red mud using acidic soil with an embedded layer of zeolite for plant growth.

    Science.gov (United States)

    Ma, Yingqun; Si, Chunhua; Lin, Chuxia

    2014-01-01

    A nearly three-year microcosm experiment was conducted to test the effectiveness of capping red mud using acidic soil with an embedded layer of zeolite in sustaining the growth of a grass species. This 'sandwich-structured' design allowed self-sustaining growth of the plants under rain-fed conditions no matter whether the underlying red mud was neutralized or not. During the initial stage, the plants grew better when the red mud was not neutralized with MgCl2 probably due to pH rise in the root zone. Neutralization of red mud led to salinization and pH decrease in the root zone. However, the difference in plant growth performance between these scenarios became less remarkable over time due to gradual improvement of soil conditions in the neutralized scenarios. Continuous leaching of soluble salts and alkali by rainwater extended the root zone to the red mud layer. As a result of vegetative production, soil organic matter rapidly accumulated. This, combined with increase in pH and decrease in salinity, markedly facilitated microbial activities and consequently improved the supply of nutrients. This study provides abasis for field-scale experimental design that will have implications for effectively establishing vegetative cover in red mud disposal sites to control dust hazards.

  8. Economics of acid gas reinjection: an innovative CO{sub 2} storage opportunity

    Energy Technology Data Exchange (ETDEWEB)

    Sam Wong; David Keith; Edward Wichert; Bill Gunter; Tom McCann [Alberta Research Council, Edmonton, AB (Canada)

    2003-07-01

    Acid gas streams, consisting primarily of hydrogen sulfide (H{sub 2}S) and carbon dioxide (CO{sub 2}), are commonly generated as a by-product of the gas sweetening process used to bring produced gases and solution gases up to pipeline specifications for sales and transport. In the past, the conventional methods for acid gas disposal are to use a Claus process or to flare the acid gas. A new technology called acid gas reinjection has emerged over the past ten years in Canada as an effective way of ensuring that acid gases are not emitted into the atmosphere. There are 38 acid gas reinjection projects presently operating in Alberta. This technology involves compressing the acid gas and injecting it into a suitable underground zone, similar to deep well disposal of produced water. Essentially, the sulfur compounds and CO{sub 2} are permanently stored in the deep geological formation preventing their release to the atmosphere. Therefore most acid gas reinjection projects can be considered as existing examples of CO{sub 2} geological storage projects. These projects provide important practical experience with CO{sub 2} storage. In addition, this technology could be extended to capture a significant fraction of the natural gas-associated CO{sub 2} stream at low cost. In this paper, a cursory economic analysis is made on one of the Alberta acid gas reinjection projects relative to sulfur recovery for determining the amount of CO{sub 2} avoided. 4 refs.

  9. Improved simultaneous gas-chromatographic analysis for homovanillic acid and vanillylmandelic acid in urine.

    Science.gov (United States)

    Leiendecker-Foster, C; Freier, E F

    1981-12-01

    We describe an improved gas-chromatographic method for the simultaneous quantitation of the catecholamine metabolites, homovanillic acid (3-methoxy-4-hydroxyphenylacetic acid) and vanillylmandelic acid (3-methoxy-4-hydroxymandelic acid). Our improvements in the method of Muskiet et al. (Clin. Chem. 23: 863, 1977) include a shorter program time and a longer silylation interval. Recovery and precision data obtained by this improved technique are similar to those of Muskiet et al. Vanillylmandelic acid results (y) were compared with those by the method of Pisano et al. (Clin. Chim. Acta 7: 285, 1962). The relation is expressed by the equation y = 0.52 + 1.05x (Sy . x = 2.33 mg/24 h and r = 0.997). Results for homovanillic acid (y) were compared with those by the method of Knight and Haymond (Clin. Chem. 23: 2007, 1977); the equation was y = 0.84 + 0.90x (Sy . x = 2.04 and r = 0.97). Retention times are also reported for several phenolic acids and other related compounds found in urine.

  10. Development of gas chromatography analysis of fatty acids in marine organisms.

    Science.gov (United States)

    Tang, Baokun; Row, Kyung Ho

    2013-08-01

    The gas chromatographic analysis of fatty acids has attracted considerable interest. In this analysis, the common derivatives of fatty acids, such as fatty acid methyl esters, can be detected using a flame ionization detector and the mass spectra can indicate the true structure of fatty acids. This paper reviews gas chromatographic methods for obtaining fatty acids from marine organisms. The stationary phase and detector for applications in gas chromatography are discussed. This article also reviews the components of fatty acids in marine animals, marine plants and marine microorganisms.

  11. Gas-grain Modeling of Isocyanic Acid (HNCO), Cyanic Acid (HOCN), Fulminic Acid (HCNO), and Isofulminic Acid (HONC) in Assorted Interstellar Environments

    Science.gov (United States)

    Quan, Donghui; Herbst, Eric; Osamura, Yoshihiro; Roueff, Evelyne

    2010-12-01

    Isocyanic acid (HNCO) is a well-known interstellar molecule. Evidence also exists for the presence of two of its metastable isomers in the interstellar medium: HCNO (fulminic acid) and HOCN (cyanic acid). Fulminic acid has been detected toward cold and lukewarm sources, while cyanic acid has been detected both in these sources and in warm sources in the Galactic Center. Gas-phase models can reproduce the abundances of the isomers in cold sources, but overproduce HCNO in the Galactic Center. Here we present a detailed study of a gas-grain model that contains these three isomers, plus a fourth isomer, isofulminic acid (HONC), for four types of sources: hot cores, the warm envelopes of hot cores, lukewarm corinos, and cold cores. The current model is partially able to rationalize the abundances of HNCO, HOCN, and HCNO in cold and warm sources. Predictions for HONC in all environments are also made.

  12. Effect of gas emissions from Tianchi volcano (NE China) on environment and its potential volcanic hazards

    Institute of Scientific and Technical Information of China (English)

    GUO; Zhengfu; LIU; Jiaqi; HAN; Jingtai; HE; Huaiyu; DAI; Guoliang; YOU; Haitao

    2006-01-01

    The Tianchi volcano in the Changbai Mountains is located on the boundary between China and North Korea. There are many times of eruptions of the Tianchi volcano during the Holocene. One of its large eruptions occurred around 1000 years ago dated by 14C method and historical records. Composition of products of the largest Tianchi volcanic eruption studied is characterized by comenditic Plinian fallout and unwelded ignimbrite, which are mainly distributed in China and North Korea. Caldera is about 4.4 km long and 3.4 km wide, which had filled with water (e.g. Tianchi Lake). The Tianchi volcanic cone is about 2700 m high above sea level. The Tianchi Lake is located on the summit of the volcanic cone, that is also highest peak of the Changbai Mountains in northeastern China. This study analyzed Cl, F, S and H2O concentrations of melt inclusions in the phenocryst minerals (anorthoclase and quartz) and co-existing matrix glasses using the electron microprobe and estimated environmental effect of Tianchi volcanic gases. The authors proposed a new method to evaluate future eruption of active volcano and estimate potential volcanic hazards based on contents of volatile emissions. Using this method, we made a perspective of future volcanic hazard in this region.

  13. Differentiation of Bacillus anthracis from Bacillus cereus by gas chromatographic whole-cell fatty acid analysis.

    OpenAIRE

    Lawrence, D.; Heitefuss, S; Seifert, H S

    1991-01-01

    Three strains of Bacillus anthracis and seven strains of Bacillus cereus were grown on complex medium and on synthetic medium. Gas chromatographic analysis of whole-cell fatty acids of strains grown on complex medium gave nearly identical fatty acid patterns. Fatty acid patterns of strains grown on synthetic medium showed a high content of branched-chain fatty acids. Significant differences between the fatty acid patterns of the two species were found. Odd iso/anteiso fatty acid ratios were a...

  14. Identification of Cyclopentenyl Fatty Acids by Gas Liquid Chromatography and Mass Spectrometry

    DEFF Research Database (Denmark)

    Shukla, V. K. S.; Abdel-Moety, E. M.; Larsen, Elfinn;

    1979-01-01

    The straight chain fatty acids and the cyclopentenyl fatty acids present in the lipids of Hydnocarpus wightiana seeds were separated as their pyrrolidides by means of gas chromatography. A gas chromatography-mass spectrometry system confirmed the complete separation and permitted the identification...

  15. Methods for upgrading of a fuel gas and succinic acid production

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention provides methods of upgrading of a CO2-containing fuel gas comprising the use of anaerobic succinic acid-producing microorganisms. Thus, the present invention provides a method for simultaneous upgrading of a CO2-containing fuel gas and biosuccinic acid production....

  16. Assessment of Volatile Organic Compound and Hazardous Air Pollutant Emissions from Oil and Natural Gas Well Pads using Mobile Remote and On-site Direct Measurements

    Science.gov (United States)

    Emissions of volatile organic compounds (VOC) and hazardous air pollutants (HAP) from oil and natural gas production were investigated using direct measurements of component-level emissions on well pads in the Denver-Julesburg (DJ) Basin and remote measurements of production pad-...

  17. Gas and particle emissions from Soufrière Hills Volcano, Montserrat, West Indies: characterization and health hazard assessment

    Science.gov (United States)

    Allen, Andrew G.; Baxter, Peter J.; Ottley, Christopher J.

    The Soufrière Hills Volcano, Montserrat, erupting since 18 July 1995, intensified its degassing in early 1996 with the continuing growth of the lava dome inside the summit crater. During this period of increased activity, between 11 and 18 March 1996, we measured gases and particles within the visible plume to determine whether at that time it posed a health risk to the population of Plymouth, the capital town, which is 5km southwest (downwind) and was then still occupied. Gravimetric measurements were made of total suspended particles (TSP) and particles having an aerodynamic diameter of less than 10μm (PM10). Measurements were made of sulphur dioxide (SO2), hydrochloric acid (HCl), hydrofluoric acid (HF), nitric acid (HNO3), acetic acid (CH3COOH), formic acid (HCOOH), and particulate sulphate (SO42-), chloride (Cl-), nitrate (NO3-), fluoride (F-), methanesulphonate (CH3SO3-), acetate (CH3COO-), formate (HCOO-), ammonium (NH4+), sodium (Na+) and acidity (H+). Trace metals having human health implications [chromium (Cr), nickel (Ni), cobalt (Co), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), tin (Sn), mercury (Hg) and lead (Pb)] were also determined. Mean concentrations of HCl, SO2 and HF obtained in the town of Plymouth were 14.0, 5.9 and 0.8ppbv, respectively. Corresponding concentrations in the mixed plume on the crater edge were 533, 168 and 22ppbv. There were no direct emissions of HNO3, although nitrate was detected in coarse particles at the source. Higher concentrations of CH3COOH and HCOOH were measured close to the crater. Mean TSP and PM10 were 64 and 15μgm-3 in Plymouth, and 455 and 47μgm-3 on the upper volcano slope. Aerosols were highly acidic at the source but rapidly neutralised during transport. Trace metals were enriched in the aerosol relative to crater surface material. The concentrations of the acid gases, sulphur dioxide in particular, and particles were found to be too small to pose a health hazard at the time of

  18. Potential hazards of compressed air energy storage in depleted natural gas reservoirs.

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Paul W.; Grubelich, Mark Charles; Bauer, Stephen J.

    2011-09-01

    This report is a preliminary assessment of the ignition and explosion potential in a depleted hydrocarbon reservoir from air cycling associated with compressed air energy storage (CAES) in geologic media. The study identifies issues associated with this phenomenon as well as possible mitigating measures that should be considered. Compressed air energy storage (CAES) in geologic media has been proposed to help supplement renewable energy sources (e.g., wind and solar) by providing a means to store energy when excess energy is available, and to provide an energy source during non-productive or low productivity renewable energy time periods. Presently, salt caverns represent the only proven underground storage used for CAES. Depleted natural gas reservoirs represent another potential underground storage vessel for CAES because they have demonstrated their container function and may have the requisite porosity and permeability; however reservoirs have yet to be demonstrated as a functional/operational storage media for compressed air. Specifically, air introduced into a depleted natural gas reservoir presents a situation where an ignition and explosion potential may exist. This report presents the results of an initial study identifying issues associated with this phenomena as well as possible mitigating measures that should be considered.

  19. Models for recurrent gas release event behavior in hazardous waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D.N. [Pacific Northwest Lab., Richland, WA (United States); Arnold, B.C. [California Univ., Riverside, CA (United States). Dept. of Statistics

    1994-08-01

    Certain radioactive waste storage tanks at the United States Department of Energy Hanford facilities continuously generate gases as a result of radiolysis and chemical reactions. The congealed sludge in these tanks traps the gases and causes the level of the waste within the tanks to rise. The waste level continues to rise until the sludge becomes buoyant and ``rolls over``, changing places with heavier fluid on top. During a rollover, the trapped gases are released, resulting, in a sudden drop in the waste level. This is known as a gas release event (GRE). After a GRE, the wastes leading to another GRE. We present nonlinear time waste re-congeals and gas again accumulates leading to another GRE. We present nonlinear time series models that produce simulated sample paths that closely resemble the temporal history of waste levels in these tanks. The models also imitate the random GRE, behavior observed in the temporal waste level history of a storage tank. We are interested in using the structure of these models to understand the probabilistic behavior of the random variable ``time between consecutive GRE`s``. Understanding the stochastic nature of this random variable is important because the hydrogen and nitrous oxide gases released from a GRE, are flammable and the ammonia that is released is a health risk. From a safety perspective, activity around such waste tanks should be halted when a GRE is imminent. With credible GRE models, we can establish time windows in which waste tank research and maintenance activities can be safely performed.

  20. Thermodynamic properties of acid gases in mixture with natural gas and water

    NARCIS (Netherlands)

    Tang, X.

    2011-01-01

    The reliable removal of acid gas components, such as carbon dioxide (CO2) and hydrogen sulfide (H2S) from natural gas is an important technical challenge. Crude oil and hydrocarbon gas streams may contain high levels of CO2 and/or H2S as contaminants. It is desirable to prevent any contaminant to re

  1. Thermal degradation events as health hazards: Particle vs gas phase effects, mechanistic studies with particles

    Science.gov (United States)

    Oberdörster, G.; Ferin, J.; Finkelstein, J.; Soderholm, S.

    Exposure to thermal degradation products arising from fire or smoke could be a major concern for manned space missions. Severe acute lung damage has been reported in people after accidental exposure to fumes from plastic materials, and animal studies revealed the extremely high toxicity of freshly generated fumes whereas a decrease in toxicity of aged fumes has been found. This and the fact that toxicity of the freshly generated fumes can be prevented with filters raises the question whether the toxicity may be due to the particulate rather than the gas phase components of the thermodegradation products. Indeed, results from recent studies implicate ultrafine particles (particle diameter in the nm range) as potential severe pulmonary toxicants. We have conducted a number of in vivo (inhalation and instillation studies in rats) and in vitro studies to test the hypothesis that ultrafine particles possess an increased potential to injure the lung compared to larger-sized particles. We used as surrogate particles ultrafine TiO 2 particles (12 and 20 nm diameter). Results in exposed rats showed that the ultrafine TiO 2 particles not only induce a greater acute inflammatory reaction in the lung than larger-sized TiO 2 particles, but can also lead to persistent chronic effects, as indicated by an adverse effect on alveolar macrophage mediated clearance function of particles. Release of mediators from alveolar macrophages during phagocytosis of the ultrafine particles and an increased access of the ultrafine particles to the pulmonary interstitium are likely factors contributing to their pulmonary toxicity. In vitro studies with lung cells (alveolar macrophages) showed, in addition, that ultrafine TiO 2 particles have a greater potential to induce cytokines than larger-sized particles. We conclude from our present studies that ultrafine particles have a significant potential to injure the lung and that their occurrence in thermal degradation events can play a major role in

  2. Ammonia Gas Detection by Tannic Acid Functionalized and Reduced Graphene Oxide at Room Temperature

    OpenAIRE

    Sweejiang Yoo; Xin Li; Yuan Wu; Weihua Liu; Xiaoli Wang; Wenhui Yi

    2014-01-01

    Reduced graphene oxide (rGO) based chemiresistor gas sensor has received much attention in gas sensing for high sensitivity, room temperature operation, and reversible. Here, for the first time, we present a promising chemiresistor for ammonia gas detection based on tannic acid (TA) functionalized and reduced graphene oxide (rGOTA functionalized). Green reductant of TA plays a major role in both reducing process and enhancing the gas sensing properties of rGOTA functionalized. Our results sho...

  3. The Chemistry Scoring Index (CSI: A Hazard-Based Scoring and Ranking Tool for Chemicals and Products Used in the Oil and Gas Industry

    Directory of Open Access Journals (Sweden)

    Tim Verslycke

    2014-06-01

    Full Text Available A large portfolio of chemicals and products is needed to meet the wide range of performance requirements of the oil and gas industry. The oil and gas industry is under increased scrutiny from regulators, environmental groups, the public, and other stakeholders for use of their chemicals. In response, industry is increasingly incorporating “greener” products and practices but is struggling to define and quantify what exactly constitutes “green” in the absence of a universally accepted definition. We recently developed the Chemistry Scoring Index (CSI which is ultimately intended to be a globally implementable tool that comprehensively scores and ranks hazards to human health, safety, and the environment for products used in oil and gas operations. CSI scores are assigned to products designed for the same use (e.g., surfactants, catalysts on the basis of product composition as well as intrinsic hazard properties and data availability for each product component. As such, products with a lower CSI score within a product use group are considered to have a lower intrinsic hazard compared to other products within the same use group. The CSI provides a powerful tool to evaluate relative product hazards; to review and assess product portfolios; and to aid in the formulation of products.

  4. Gas chromatography of volatile fatty acids. Method involving separation from biological material by vacuum distillation.

    Science.gov (United States)

    Tyler, J E; Dibdin, G H

    1975-02-19

    A method is described for the quantitation of C2-C5 volatile fatty acids present in biological tissues. It involved recovery of the acids from their biological matrix by vacuum micro-distillation at room temperature, followed by gas phase separation of aqueous solutions on orthophosphoric acid-modified Phasepak Q columns. The subsequent gas chromatographic procedure resolved iso from normal isomers and showed a linear response for each volatile acid over the range 10-400 ng. There was no evidence of ghosting, isomer peak broadening, or peak tailing. Relative molar response values were shown to be linear with carbon number for all the volatile fatty acids studied.

  5. Ruminal Methane Production on Simple Phenolic Acids Addition in in Vitro Gas Production Method

    OpenAIRE

    A. Jayanegara

    2009-01-01

    Methane production from ruminants contributes to total global methane production, which is an important contributor to global warming. In this experiment, six sources of simple phenolic acids (benzoic, cinnamic, phenylacetic, caffeic, p-coumaric and ferulic acids) at two different levels (2 and 5 mM) added to hay diet were evaluated for their potential to reduce enteric methane production using in vitro Hohenheim gas production method. The measured variables were gas production, methane, orga...

  6. Multifunctional acid formation from the gas-phase ozonolysis of beta-pinene.

    Science.gov (United States)

    Ma, Yan; Marston, George

    2008-10-28

    The gas-phase ozonolysis of beta-pinene was studied in static chamber experiments, using gas chromatography coupled to mass spectrometric and flame ionisation detection to separate and detect products. A range of multifunctional organic acids-including pinic acid, norpinic acid, pinalic-3-acid, pinalic-4-acid, norpinalic acid and OH-pinalic acid-were identified in the condensed phase after derivatisation. Formation yields for these products under systematically varying reaction conditions (by adding different OH radical scavengers and Criegee intermediate scavengers) were investigated and compared with those observed from alpha-pinene ozonolysis, allowing detailed information on product formation mechanisms to be elucidated. In addition, branching ratios for the initial steps of the reaction were inferred from quantitative measurements of primary carbonyl formation. Atmospheric implications of this work are discussed.

  7. Measurement of abscisic acid and gibberellins by gas chromatography/mass spectrometry.

    Science.gov (United States)

    Okamoto, Masanori; Hanada, Atsushi; Kamiya, Yuji; Yamaguchi, Shinjiro; Nambara, Eiji

    2009-01-01

    Gas chromatography-mass spectrometry (GC-MS)-based analysis is an accurate and sensitive method to quantify plant hormones. This method is commonly used for analysis of low-molecular-weight compounds, such as abscisic acid (ABA), gibberellins (GAs), auxins, and brassinosteroids. Procedures are composed of four major steps: extraction, fractionation, derivatization, and detection. Here, we describe a protocol for quantification of ABA and GAs.

  8. CO2 Capture from Flue Gas using Amino Acid Salt Solutions

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai; Stenby, Erling Halfdan; Thomsen, Kaj

    2009-01-01

    difficult. Amino acid salt solutions have emerged as an alternative to the alkanolamine solutions. A number of advantages make amino acid salt solutions attractive solvents for CO2 capture from flue gas. In the present study CO2 absorption in aqueous solutions of 0.5 M potassium glycinate and 0.5 M...

  9. Comparison of gas-phase acidities of some carbon acids with their rates of hydron exchange in methanolic methoxide

    NARCIS (Netherlands)

    DeTuri, V.F.; Koch, H.F.; Koch, J.G.; Lodder, G.; Mishima, M.; Zuilhof, H.; Abrams, N.M.; Anders, C.E.; Biffinger, J.C.; Han, P.; Kurland, A.R.; Nichols, J.M.; Ruminski, A.M.; Smith, P.R.; Vasey, K.D.J.

    2006-01-01

    Hydron exchange reaction rates, k(exch)M(-1) s(-1), using methanolic sodium methoxide are compared with gas-phase acidities, Delta G(Acid)(0) kcal/mol, for four 9-YPhenylfluorenes-9-H-i, seven (YC6H4CH)-H-i(CF3)(2), seven YC6H4-(CHClCF3)-H-i, and (C6F5H)-H-i. Fourteen of the fluorinated benzylic com

  10. Highly Adsorptive, MOF-Functionalized Nonwoven Fiber Mats for Hazardous Gas Capture Enabled by Atomic Layer Deposition

    Science.gov (United States)

    2014-03-20

    opportunities. Integration of MOFs on polymeric fibrous scaffolds will enable new applications in gas adsorption, membrane separation, catalysis...potential for gas adsorption and storage, their powder form limits deployment opportunities. Integration of MOFs on polymeric fibrous scaffolds will enable...MOFs on polymeric fi brous scaffolds will enable new applications in gas adsorption, membrane separation, catalysis, and toxic gas sensing. Here

  11. 危险废物焚烧的烟气污染物的控制和净化探讨%Control and Purification Discussion of Flue Gas Pollutes of Hazardous Waste Incineration

    Institute of Scientific and Technical Information of China (English)

    吉鹏

    2012-01-01

    危险废物焚烧产生的烟气包括卤化物、硫的氧化物、氮氧化物、重金属、二恶英等。如何处理这些危险废物焚烧产物,达到欧盟EU/2000/76/EC排放标准是本项目的关键。%Hazardous waste incineration flue gas,including acid gases,such as halides,sulfur oxides,nitrogen oxides,heavy metals,dioxins.How to dispose of incineration of these products so as to meet EU2000/76/EC emission standards is the key to the project.

  12. 40 CFR 60.648 - Optional procedure for measuring hydrogen sulfide in acid gas-Tutwiler Procedure. 1

    Science.gov (United States)

    2010-07-01

    ... hydrogen sulfide in acid gas-Tutwiler Procedure. 1 60.648 Section 60.648 Protection of Environment... procedure for measuring hydrogen sulfide in acid gas—Tutwiler Procedure. 1 1 Gas Engineers Handbook, Fuel.... In principle, this method consists of titrating hydrogen sulfide in a gas sample directly with...

  13. Evaluation of Gas-Cooled Pressurized Phosphoric Acid Fuel Cells for Electric Utility Power Generation

    Science.gov (United States)

    Faroque, M.

    1983-01-01

    Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas-cooling was already demonstrated in atmospheric pressure stacks. Theoretical and experimental investigations of gas-cooling for pressurized PAFC are presented. Two approaches to gas cooling, Distributed Gas-Cooling (DIGAS) and Separated Gas-Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

  14. Evaluation of gas cooling for pressurized phosphoric acid fuel cell stacks

    Science.gov (United States)

    Farooque, M.; Skok, A. J.; Maru, H. C.; Kothmann, R. E.; Harry, R. W.

    1983-01-01

    Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas cooling has already been demonstrated in atmospheric pressure stacks. This paper presents theoretical and experimental investigation of gas cooling for pressurized PAFC. Two approaches to gas cooling, Distributed Gas Cooling (DIGAS) and Separated Gas Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

  15. Identification and determination of erucic acid in infant formula using Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Sabzevari O

    2007-05-01

    Full Text Available Background: Infant formula, depending on the source, contains various fatty acids, which may possess important nutritional and biological value for infants. The presence of some of these fatty acids in infant formula, however, can be harmful and toxic for the infant. In this regard, more attention has been paid to erucic acid since its accumulation in myocardial tissues may cause damage to the heart. Therefore, a limit has been set by the Codex Alimentarius for the presence of erucic acid in infant formula (less than 1% of total fatty acids. The purpose of the present study is to investigate amount of erucic acid present in three infant formulas used predominantly in Iran. Methods: Gas chromatography (GC is a valuable method applied for the separation of fatty acids, including erucic acid, from oils and oily food. Three brands of infant formulas, namely Humana, Biomil and Multi, were analyzed by GC using a wall coated open tubular (WCOT fused silica column and flame ionization detector (FID. Heneicosanoic acid was employed as an internal standard. Results: The findings showed that Humana and Biomil infant formula samples contained 0.06% and 0.002% erucic acid (from total fatty acids, respectively, while no erucic acid was detected in the Multi infant formula samples. Conclusion: The amount of erucic acid in the studied infant formulas was far below the Codex limit of 1% total fatty acids.

  16. GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

    Science.gov (United States)

    AbstractThe need for the development of polymeric materials based on renewable resources has led to the development of poly(lactic acid) (PLA) which is being produced from a feedstock of corn rather than petroleum. The present study examines the permeation of nitrogen...

  17. Gas Phase Structure of Amino Acids: La-Mb Studies

    Science.gov (United States)

    Mata, I. Pena S.; Sanz, M. E.; Vaquero, V.; Cabezas, C.; Perez, C.; Blanco, S.; López, J. C.; Alonso, J. L.

    2009-06-01

    Recent improvements in our laser ablation molecular beam Fourier transform microwave (LA-MB-FTMW) spectrometer such as using Laval-type nozzles and picoseconds Nd:YAG lasers (30 to 150 ps) have allowed a major step forward in the capabilities of this experimental technique as demonstrated by the last results in serine cysteine and threonine^a for which seven, six and seven conformers have been respectively identified. Taking advantage of these improvements we have investigated the natural amino acids metionine, aspartic and glutamic acids and the γ-aminobutyric acid (GABA) with the aim of identify and characterize their lower energy conformers. Searches in the rotational spectra have lead to the identification of seven conformers of metionine, six and five of aspartic and glutamic acids, respectively, and seven for the γ-aminobutyric. These conformers have been unambiguously identified by their spectroscopic constants. In particular the ^{14}N nuclear quadrupole coupling constants, that depend heavily on the orientation of the amino group with respect to the principal inertial axes of the molecule, prove to be a unique tool to distinguish unambigously between conformations with similar rotational constants. For the γ-aminobutyric acid two of the seven observed structures are stablized by an intramolecular interaction n-π*. Two new conformers of proline have been identified together with the two previously observed. J. L. Alonso, C. Pérez, M. E. Sanz, J. C. López, S. Blanco, Phys.Chem.Chem.Phys., 2009, 11, 617. D. B. Atkinson, M. A. Smith, Rev. Sci. Instrum. 1995, 66, 4434 S. Blanco, M. E. Sanz, J. C. López, J. L. Alonso, Proc. Natl. Acad. Sci. USA2007, 104, 20183. M. E. Sanz, S. Blanco, J. C. López, J. L. Alonso, Angew. Chem. Int. Ed.,2008, 120, 6312. A. Lesarri, S. Mata, E. J. Cocinero, S. Blanco, J.C. López, J. L. Alonso, Angew. Chem. Int. Ed. , 2002, 41, 4673

  18. Effects of emulsified octadecanic acids on gas production and cellulolysis by the rumen anaerobic fungus, Piromyces communis M014.

    Science.gov (United States)

    Kim, Chang-H; Lee, Shin J; Ha, Jong K; Kim, Wan Y; Lee, Sung S

    2008-02-01

    Responses of the rumen anaerobic fungus, Piromyces communis M014, to octadecanic long-chain fatty acids (LCFAs) were evaluated by measuring total and hydrogen gas productions, filter paper (FP) cellulose degradation and polysaccharidase enzyme activities. Octadecanic acids (stearic acid, C(18:0); oleic acid, C(18:1); linoleic acid, C(18:2) and linolenic acid, C(18:3)) were emulsified by ultrasonication under anaerobic conditions, and added to the medium at the level of 0.001%. When P. communis M014 was grown in culture with stearic and oleic acids, the cumulative gas production, FP cellulose digestion and enzyme activities were significantly (pinhibited all of the investigated parameters, including cellulose degradation, enzyme activities and gas production, up to 168h incubation. These results indicated that stearic and oleic acids tended to have stimulatory effects on fungal cellulolysis, whereas linolenic acid caused a significant (pinhibition of gas production and cellulase enzyme activity was.

  19. Sulfur recovery from low H{sub 2}S content acid gas using catalytic partial oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Clark, P.D.; Dowling, N.I.; Huang, M.

    2010-01-15

    The poster presentation discussed a new strategy for recovering sulfur from low hydrogen-sulphide-content acid gas using catalytic partial oxidation. In a new technology for dealing with BTX-contaminated lean acid gas, a catalytic reactor replaces the burner-furnace stage to achieve BTX conversion greater than 95 percent and control the hydrogen sulfide/sulfur dioxide ratio. The product gas is then sent to the Claus catalytic converters. The best catalysts for this process are alumina-supported Co-Mo and y-alumina. This process was compared with SELECTOX, another process that deals with poor acid gas with BTX conversion better than 95 percent. Catalytic oxidation can deal with a higher BTX feed content than SELECTOX, but the running temperature is higher. Both processes produce acceptable sulfur quality. To improve this process, the quality of the sulfur produced and the lifetime of the catalyst need to be increased, and an economic way to increase the heat to reach the running temperature needs to be found. The partial oxidation (POX) of CH{sub 4} solves both of these problems. The catalytic POX of acid gas is combined with the POX of fuel gas in the pre-heating zone. This process has the advantage that the burner-furnace stage of the Claus process can be replaced by a stream containing H{sub 2}S/SO{sub 2}=2; the reaction is performed at its adiabatic temperature requiring only a small amount of fuel gas; the presence of H{sub 2} and CO produced by the POX of fuel gas improves the quality of sulfur; the catalyst remains active for about 30 hours; and the process can tolerate high BTX content. 6 tabs., 2 figs.

  20. Effect of oxygen enrichment in air on acid gas combustion under Claus conditions

    KAUST Repository

    Ibrahim, Salisu

    2013-09-01

    Results are presented to examine the combustion of acid gas (H2S and CO2) in hydrogen-fueled flames using a mixture of oxygen and nitrogen under Claus conditions (Φ = 3). Specifically the effect of oxygen enrichment in the above flames is examined. The compositions of acid gas examined are100% H2S and 50% H2S/50% CO2 with different percentages of oxygen enrichment (0%, 19.3% and 69.3%) in the oxygen/nitrogen mixtures. The results revealed that combustion of acid gas formed SO2 wherein the mole fraction of SO2 increased to an asymptotic value at all the oxygen concentrations examined. In addition, increase in oxygen enrichment of the air resulted in increased amounts of SO2 rather than the formation of more desirable elemental sulfur. In case of 50% H2S/50% CO2 acid gas, carbon monoxide mole fraction increased with oxygen enrichment which is an indicator to the availability of additional amounts of oxygen into the reaction pool. This gas mixture resulted in the formation of other sulfurous–carbonaceous compounds (COS and CS2) due to the presence of carbon monoxide. The results showed that the rate of COS formation increased with oxygen enrichment due to the availability of higher amounts of CO while that of CS2 reduced. The global reactions responsible for this observed phenomenon are presented.

  1. Synthesis of porous starch xerogels modified with mercaptosuccinic acid to remove hazardous gardenia yellow.

    Science.gov (United States)

    Bao, Liping; Zhu, Xinyi; Dai, Hongxia; Tao, Yongxin; Zhou, Xiaoying; Liu, Wenjie; Kong, Yong

    2016-08-01

    Mercaptosuccinic acid (MSA) molecules were inserted into potato starch, leading to the breaking of intrinsic H-bonds within macromolecular chains of starch and the formation of intermolecular H-bonds between MSA and starch, which could be verified by Fourier transform infrared spectroscopy (FT-TR). MSA modified porous starch xerogels (PSX/MSA) were obtained after freeze-drying the MSA modified starch, and they were characterized by field emission scanning electron microscopy (FESEM), exhibiting the intriguing porous structure due to the separation of starch chains by MSA molecules. The PSX/MSA were then used as the adsorbents to remove gardenia yellow (GY), a natural colorant with genotoxicity. Due to the porous structure of PSX and the introduced carboxyl groups from MSA, the adsorption capacity of the PSX/MSA was much higher than that of the starch xerogels alone (SX). The adsorption behaviors of GY by the PSX/MSA fitted both the Freundlich isotherm model and the pseudo-second-order kinetic model, and the efficient adsorption of GY suggested that the PSX/MSA might be potential adsorbents for the removal of dyes from contaminated aquatic systems.

  2. Determination of Free Fatty Acids and Triglycerides by Gas Chromatography Using Selective Esterification Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Kail, Brian W; Link, Dirk D; Morreale, Bryan D

    2012-11-01

    A method for selectively determining both free fatty acids (FFA) and triacylglycerides (TAGs) in biological oils was investigated and optimized using gas chromatography after esterification of the target species to their corresponding fatty acid methyl esters (FAMEs). The method used acid catalyzed esterification in methanolic solutions under conditions of varying severity to achieve complete conversion of more reactive FFAs while preserving the concentration of TAGs. Complete conversion of both free acids and glycerides to corresponding FAMEs was found to require more rigorous reaction conditions involving heating to 120°C for up to 2 h. Method validation was provided using gas chromatography–flame ionization detection, gas chromatography–mass spectrometry, and liquid chromatography–mass spectrometry. The method improves on existing methods because it allows the total esterified lipid to be broken down by FAMEs contributed by FFA compared to FAMEs from both FFA and TAGs. Single and mixed-component solutions of pure fatty acids and triglycerides, as well as a sesame oil sample to simulate a complex biological oil, were used to optimize the methodologies. Key parameters that were investigated included: HCl-to-oil ratio, temperature and reaction time. Pure free fatty acids were found to esterify under reasonably mild conditions (10 min at 50°C with a 2.1:1 HCl to fatty acid ratio) with 97.6 ± 2.3% recovery as FAMEs, while triglycerides were largely unaffected under these reaction conditions. The optimized protocol demonstrated that it is possible to use esterification reactions to selectively determine the free acid content, total lipid content, and hence, glyceride content in biological oils. This protocol also allows gas chromatography analysis of FAMEs as a more ideal analyte than glyceride species in their native state.

  3. Determination of free fatty acids and triglycerides by gas chromatography using selective esterification reactions.

    Science.gov (United States)

    Kail, Brian W; Link, Dirk D; Morreale, Bryan D

    2012-01-01

    A method for selectively determining both free fatty acids (FFA) and triacylglycerides (TAGs) in biological oils was investigated and optimized using gas chromatography after esterification of the target species to their corresponding fatty acid methyl esters (FAMEs). The method used acid catalyzed esterification in methanolic solutions under conditions of varying severity to achieve complete conversion of more reactive FFAs while preserving the concentration of TAGs. Complete conversion of both free acids and glycerides to corresponding FAMEs was found to require more rigorous reaction conditions involving heating to 120°C for up to 2 h. Method validation was provided using gas chromatography-flame ionization detection, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry. The method improves on existing methods because it allows the total esterified lipid to be broken down by FAMEs contributed by FFA compared to FAMEs from both FFA and TAGs. Single and mixed-component solutions of pure fatty acids and triglycerides, as well as a sesame oil sample to simulate a complex biological oil, were used to optimize the methodologies. Key parameters that were investigated included: HCl-to-oil ratio, temperature and reaction time. Pure free fatty acids were found to esterify under reasonably mild conditions (10 min at 50°C with a 2.1:1 HCl to fatty acid ratio) with 97.6 ± 2.3% recovery as FAMEs, while triglycerides were largely unaffected under these reaction conditions. The optimized protocol demonstrated that it is possible to use esterification reactions to selectively determine the free acid content, total lipid content, and hence, glyceride content in biological oils. This protocol also allows gas chromatography analysis of FAMEs as a more ideal analyte than glyceride species in their native state.

  4. An integrated approach for the evaluation of technological hazard impacts on air quality: the case of the Val d'Agri oil/gas plant

    Directory of Open Access Journals (Sweden)

    M. Calvello

    2014-04-01

    Full Text Available 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.

  5. Estimating Fatty Acid Composition of Infant Buccal Mucosal Cells by Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    CHEN Fei; ZHANG Wei-li; LI Fang; ZHU Xiao-dong; ZHU Jian-xing

    2008-01-01

    Long chain polyunsaturated fatty adds, i. e., docosahexaenoic acid (DHA or C22 : 6n -3), arachidonic acid (AA or C20 : 4n - 6) have been identified as essential fatty acids and play an important role in growth and development of infants. Mensurement of fatty acid composition is usually by collection of blood, but to obtain blood in infants is difficult. Nowadays, the fatty acid composition can be estimated by collecting buccal mucosal cells, which can avoid repeated blood sampling. The purpose of this paper is to compare the fatty acid composition of cheek calls with that of plasma and red blood cells (RBCs). In this study, twenty-seven infants were enrolled, and buccal mucosal cells and blood samples were obtained from these infants of the same time. Fatty acid composition of buccal mucesal cells, plasma and RBCs were measured by capillary gas chromatography. The results show that the contents of AA and DHA in the buccal mucosal cells are correlated well with that in the plasma [r=0.36 (P=0.042) and r=0.38 (P=0.033), respectively]. The ratio of AA to DHA is 1.32% in buccal mucosal cells, 1.60% in plasma and 1.55% in RBCs and there are no significant differences among groups (P = 0.134). It shows that the fatty acid composition in buccal mucosal cells can reflect the fat nutrition status in infants and can be detected by capillary gas chromatography. Estimating fatty acid composition of buccal mucosal cells in infants by capillary gas chromatography is feasible, and because of its noninvasiveness, it can be suitable for nutrition research in infants.

  6. 75 FR 35796 - Busan 74 (2-hydroxypropyl methanethiosulfonate); Chlorine Gas; and Dichromic Acid, et al...

    Science.gov (United States)

    2010-06-23

    ... AGENCY Busan 74 (2-hydroxypropyl methanethiosulfonate); Chlorine Gas; and Dichromic Acid, et al... Number, E-mail Address Busan 74 (2-hydroxypropyl EPA-HQ-OPP-2010-02 K. Avivah Jakob methanethiosulfonate... protection, Pesticides and pests, Antimicrobials, Busan 74 (2-hydroxypropyl methanethiosulfonate);...

  7. 含硫化氢天然气泄漏事故的硫化氢中毒灾害分析%A new method for analyzing the hazardous hydrogen sulfide poisoning caused by the sulfurous natural gas leakage

    Institute of Scientific and Technical Information of China (English)

    雷达; 张建文; 冯文兴

    2012-01-01

    应用前文建立的天然气长输管道泄漏扩散模型,在大量事故统计分析基础上,针对含硫化氢天然气泄漏后硫化氢导致的化学灾害后果提出了一种新的风险分析方法.综合考虑概率风险评价法和伤害范围评价法的特点,研究了不同规模泄漏事故可能导致的个人风险和社会风险,并绘制了相应的社会风险曲线图.%The present paper is aimed to introduce a new method for analyzing the hydrogen sulfide poisoning hazards caused by the sulfurous natural gas leakage. As is well known, China is rich in sulfurous natural gas, whose deposits are huge and widely distributed in our country. However, due to its toxic nature, the release of hydrogen sulfide-containing natural gas from the pipeline tends to bring about serious threats to human life and material property near its leakage source. To predict or evaluate the threat of hydrogen sulfide poisoning , a lot of measures can be taken to test or evaluate such hydrogen sulfide poisoning source, and QRA (Quantitative Hazard Analysis) method can be thought of as an effective one. But, the above said analysis method doesn t seem enough for the sake of security management of its exploration, letting alone to do the quantitative hazards, such as individual intake hazard and societal hazard, for ex- ample, the community poisoning threat. It is for this need that we would like to propose a new analysis method for hydrogen sulfide poisoning of hydrogen sulfide-bearing natural gas known as the comprehensive hazards analysis method, based on the study of the historical accident-statistical data of EGIG ( European Gas Pipeline Incident Data Group) and BG Transco, while the probability of hazard and the scope of the damage were taken into account. While working at our method, we have also analyzed the three leakage scenarios of the East-Sichuan Gas Transportation Project, including the individual hazard analysis and societal hazard analysis. In addition

  8. The experimental and theoretical gas phase acidities of adenine, guanine, cytosine, uracil, thymine and halouracils

    Science.gov (United States)

    Chen, Edward C. M.; Herder, Charles; Chen, Edward S.

    2006-10-01

    The gas phase acidities GPA (Δ H (298) for deprotonation) of the most stable tautomers of adenine, guanine, cytosine, uracil and thymine are evaluated. New GPA are obtained from electron impact spectra and acid dissociation constants measured in dimethylsulfoxide for A, U and 5-FU. The average experimental GPA are: [N1 sbnd H] C 340(2); T 333(2); U 333(2); 5-FU 329(4); [N9 sbnd H] A 333(1); G 332(4); all in kcal/mol. Only cytosine is a weaker acid than HCl in the gas phase. The most acidic hydrogens in the nucleotides are replaced by the sugar in DNA and RNA. The experimental N3 sbnd H GPA are G 334(4); U 347(2), T 347(4), while the predicted N3 sbnd H 5-FU GPA is 343 kcal/mol. The NH sbnd H GPA are: C 346(4); A 352(2); G 336(4) (all in kcal/mol). These are supported by semi-empirical multiconfiguration configuration interaction calculations. The predicted C8 sbnd H acidities of G and A and the C6 sbnd H of T are about the same, 360(2) kcal/mol. The remaining CH acidities are 370-380 kcal/mol. The 5-halouracils are predicted to be more acidic than HCl.

  9. Impact of individual acid flue gas components on mercury capture by heat-treated activated carbon

    Institute of Scientific and Technical Information of China (English)

    Jian-ming ZHENG; Jin-song ZHOU; Zhong-yang LUO; Ke-fa CEN

    2012-01-01

    Elemental mercury capture on heat-treated activated carbon (TAC) was studied using a laboratory-scale fixed bed reactor.The capability of TAC to perform Hg0 capture under both N2 and baseline gas atmospheres was studied and the effects of common acid gas constituents were evaluated individually to avoid complications resulting from the coexistence of multiple components.The results suggest that surface functional groups (SFGs) on activated carbon (AC) are vital to Hg0 capture in the absence of acid gases.Meanwhile,the presence of acid gas components coupled with defective graphitic lattices on TAC plays an important role in effective Hg0 capture.The presence of HCl,NO2,and NO individually in basic gases markedly enhances Hg0 capture on TAC due to the heterogeneous oxidation of Hg0 on acidic sites created on the carbon surface and catalysis by the defective graphitic lattices on TAC.Similarly,the presence of SO2 improves Hg0 capture by about 20%.This improvement likely results from the deposition of sulfur groups on the AC surface and oxidation of the elemental mercury by SO2 due to catalysis on the carbon surface.Furthermore,O2 exhibits a synergistic effect on Hg0 oxidation and capture when acid gases are present in the flue gases.

  10. Gas chromatography-vacuum ultraviolet spectroscopy for analysis of fatty acid methyl esters.

    Science.gov (United States)

    Fan, Hui; Smuts, Jonathan; Bai, Ling; Walsh, Phillip; Armstrong, Daniel W; Schug, Kevin A

    2016-03-01

    A new vacuum ultraviolet (VUV) detector for gas chromatography was recently developed and applied to fatty acid methyl ester (FAME) analysis. VUV detection features full spectral acquisition in a wavelength range of 115-240nm, where virtually all chemical species absorb. VUV absorption spectra of 37 FAMEs, including saturated, monounsaturated, and polyunsaturated types were recorded. Unsaturated FAMEs show significantly different gas phase absorption profiles than saturated ones, and these classes can be easily distinguished with the VUV detector. Another advantage includes differentiating cis/trans-isomeric FAMEs (e.g. oleic acid methyl ester and linoleic acid methyl ester isomers) and the ability to use VUV data analysis software for deconvolution of co-eluting signals. As a universal detector, VUV also provides high specificity, sensitivity, and a fast data acquisition rate, making it a powerful tool for fatty acid screening when combined with gas chromatography. The fatty acid profile of several food oil samples (olive, canola, vegetable, corn, sunflower and peanut oils) were analyzed in this study to demonstrate applicability to real world samples.

  11. Analyzing solubility of acid gas and light alkanes in triethylene glycol

    Institute of Scientific and Technical Information of China (English)

    Alireza Bahadori; Had B.Vuthaluru; Saeid Mokhatab

    2008-01-01

    Physical solvents such as ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) are commonly used in wet gas dehydration processes with TEG being the most popular due to ease of regeneration and low solvent losses. Unfortunately, TEG absorbs significantly more hydrocarbons and acid gases than EG or DEG. Quantifying this amount of absorption is therefore critical in order to minimize hydrocarbon losses or to optimize hydrocarbon recovery depending on the objective of the process. In this article, a new correlation that fully covers the operating ranges of TEG dehydration units is developed in order to determine the solubility of light alkanes and acid gases in TEG solvent. The influence of several parameters on hydrocarbon and acid gas solubility including temperature, pressure, and solvent content is also examined.

  12. Amino acid salt solutions as solvents in CO2 capture from flue gas

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai; Thomsen, Kaj; Stenby, Erling Halfdan

    solutions is their ability to form solid precipitates upon the absorption of CO2. The occurrence of crystallization offers the possibility of increasing the CO2 loading capacity of the solvent. However, precipitation can also have negative effect on the CO2 capture process. The chemical nature of the solid...... loading capacity of aqueous solutions of the potassium salts of selected amino-acids (glycine, taurine, lysine proline, and glutamic acid) were examined, and the relation between the initial amino acid salt concentration and precipitation ability of each solution were determined. Experiments were...... of glycine, taurine, and lysine, while in the case of proline, and glutamic acid, the precipitate was found to be bicarbonate. These results give an important contribution to further understanding the potential of amino acid salt solutions in CO2 capture from flue gas....

  13. Effect of acid density of HZSM-5 on the oligomerization of ethylene in FCC dry gas

    Institute of Scientific and Technical Information of China (English)

    Xue Ding; Shan Geng; Chunyi Li; Chaohe Yang; Guohui Wang

    2009-01-01

    The oligomerization of ethylene in FCC dry gas over HZSM-5 catalyst with different Si/Al2 ratios was studied. The effect of acid density of catalyst on the oligomerization of ethylene was discussed. By increasing the acid density of catalyst, ethylene conversion showed a linear increase, while the yields of olefins decreased when the acid density of catalyst exceeded 0.14 mmolNH3/g owing to a promotion of hydrogen transfer reaction. Through comparing the average distance between acid sites on catalyst with kinetic diameters of olefins, it was found that the dimerization of ethylene was not restrained by the sparse distribution of acid sites, while the hydrogen transfer reaction of C3 and C4 olefins was limited. On these bases, a conclusion is proposed that the dimerization of ethylene proceeded via Eley-Rideal mechanism, while the hydrogen transfer reaction of C3 and C4 olefins followed the Langmuir-Hinshelwood mechanism.

  14. Limiting Current of Oxygen Reduction on Gas-Diffusion Electrodes for Phosphoric Acid Fuel Cells

    DEFF Research Database (Denmark)

    Li, Qingfeng; Gang, Xiao; Hjuler, Hans Aage;

    1994-01-01

    Various models have been devoted to the operation mechanism of porous diffusion electrodes. They are, however, suffering from the lack of accuracy concerning the acid-film thickness on which they are based. In the present paper the limiting current density has been measured for oxygen reduction...... on polytetrafluorine-ethyl bonded gas-diffusion electordes in phosphoric acid with and without fluorinated additives. This provides an alternative to estimate the film thickness by combining it with the acid-adsorption measurements and the porosity analysis of the catalyst layer. It was noticed that the limiting...... expression for the limiting current density. The acid-film thickness estimated this way was found to be of 0.1 mum order of magnitude for the two types of electrodes used in phosphoric acid with and without fluorinated additives at 150-degrees-C....

  15. Rapid Detection of Gas Hazards and Leaks with an Atmospheric Sampling, High Resolution, Mass Spectrometer with Low Pumping Requirements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Miniaturization of mass spectrometers is restricted almost exclusively by the ability of small vacuum pumps to remove gas loads during operation of the instrument....

  16. Evaluation of Aroma in Oriental Tobaccos as Based On Valeric Acid Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Dagnon S

    2014-12-01

    Full Text Available Levels of valeric acids (isovaleric and 3-methylvaleric in leaves and smoke of different tobacco types were quantified by capillary gas chromatography (GC using flame ionization detector (FID. The aroma characteristics of the smoke were scored by sensory evaluation. It was found that leaves of Oriental and burley tobaccos contain higher amounts of both valeric acid derivatives than Virginia tobaccos containing isovaleric acid but no 3-methylvaleric acid. Strong correlation between the aroma and pleasantness scores of smoke and the content of valeric acids in the leaves of Oriental tobaccos was observed, while it was not the case for leaves of Virginia and burley tobaccos. In all tobacco types no correlation between smoking characteristics and the content of valeric acids in the smoke was established. Regression models involving leaf isovaleric acid were developed that can be used to evaluate aroma and pleasantness of smoke in Oriental tobaccos. The data obtained allow the following conclusions to be drawn: a 3-methylvaleric acid may be a chemical marker to distinguish Virginia tobaccos from Oriental and burley tobaccos; b isovaleric acid content in leaves of Oriental tobaccos may be used for objective aroma evaluation that can be exploited for breeding and market purposes.

  17. QUANTITATIVE DETERMINATION OF FATTY ACIDS IN INFANT FORMULA BY GAS CHROMATOGRAPHY WITHOUT DERIVATIZATION

    Directory of Open Access Journals (Sweden)

    M. R. Oveisi

    2006-08-01

    Full Text Available Fatty acids play important roles in biological systems and the newborns fatty acids requirements are covered only by the milk. It is of particular interest to qualify the content of the fatty acids in the milk. This study was performed to determine the levels of some fatty acids in the infant formulas and also to describe a method without derivatization for the fatty acids analysis and applying it to the control of infant formulas. Free fatty acids were produced by adding isopropanol- KOH to milk fat extract and heating it to saponify and acidify by H2SO4. Free fatty acids were extracted and were quantified by capillary gas chromatography on a fused silica column (AT-1000 and flame ionization detector. The average experimental values of lauric, palmitic, stearic and linoleic fatty acids contents of twenty infant formulas were 6.47, 16.52, 2.11 and 14.56 g/100g, respectively. The obtained experimental values of lauric and linoleic fatty acids contents of twenty infant formulas were in good agreement with the values proposed by standards of codex alimentary.

  18. Determination of 4-Chloroindole-3-Acetic Acid Methyl Ester in Lathyrus Vicia and Pisum by Gas Chromatography - Mass Spectrometry

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen; Egsgaard, Helge; Larsen, Elfinn

    1980-01-01

    4-Chloroindole-3-acetic acid methyl ester was identified unequivocally in Lathyrus latifolius L., Vicia faba L. and Pisum sativum L. by thin layer chromatography, gas chromatography and mass spectrometry. The gas chromatographic system was able to separate underivatized chloroindole-3-acetic acid...... methyl ester isomers. The quantitative determination of 4-chloroindole-3-acetic acid methyl ester in immature seeds of these three species was performed by gas chromatography – mass spectrometry using deuterium labelled 4-chloro-indole-3-acetic acid methyl ester as an internal standard. P. sativum...

  19. Ruminal Methane Production on Simple Phenolic Acids Addition in in Vitro Gas Production Method

    Directory of Open Access Journals (Sweden)

    A. Jayanegara

    2009-04-01

    Full Text Available Methane production from ruminants contributes to total global methane production, which is an important contributor to global warming. In this experiment, six sources of simple phenolic acids (benzoic, cinnamic, phenylacetic, caffeic, p-coumaric and ferulic acids at two different levels (2 and 5 mM added to hay diet were evaluated for their potential to reduce enteric methane production using in vitro Hohenheim gas production method. The measured variables were gas production, methane, organic matter digestibility (OMD, and short chain fatty acids (SCFA. The results showed that addition of cinnamic, caffeic, p-coumaric and ferulic acids at 5 mM significantly (P p-coumaric > ferulic > cinnamic. The addition of simple phenols did not significantly decrease OMD. Addition of simple phenols tends to decrease total SCFA production. It was concluded that methane decrease by addition of phenolic acids was relatively small, and the effect of phenolic acids on methane decrease depended on the source and concentration applied.

  20. Revision of the gas-phase acidity scale below 300 kcal mol(-1).

    Science.gov (United States)

    Leito, Ivo; Raamat, Elin; Kütt, Agnes; Saame, Jaan; Kipper, Karin; Koppel, Ilmar A; Koppel, Ivar; Zhang, Min; Mishima, Masaaki; Yagupolskii, Lev M; Garlyauskayte, Romute Yu; Filatov, Andrey A

    2009-07-23

    The gas-phase acidity (GA) scale from (CF(3)CO)(2)NH to (C(2)F(5)SO(2))(2)NH--about a 24 kcal mol(-1) range of gas-phase acidities--was reexamined using the Fourier transform ion cyclotron resonance equilibrium measurement approach. Some additions and modifications to the standard methodology of GA measurements were introduced (estimation of partial pressures from mass spectra of the compounds, instead of the pressure gauge readings and use of long reaction times) to achieve higher reliability. Gas-phase acidities of 18 compounds were determined for the first time. The results reveal a contraction of the previously published values in this part of the scale. In particular, the GA values of (CF(3)SO(2))(2)NH and (C(2)F(5)SO(2))(2)NH (important components of lithium ion battery electrolytes and ionic liquids) were revised toward stronger acidities from 291.8 kcal mol(-1) to 286.5 kcal mol(-1) and from 289.4 kcal mol(-1) to 283.7 kcal mol(-1) (i.e., by 5.3 and 5.7 kcal mol(-1)), respectively. Experimental and computational evidence is presented in support of the current results.

  1. Amino Acids and Sugars in the Gas Phase: Microwave Data for Astrochemistry

    Science.gov (United States)

    Mata, S.; Cabezas, C.; Varela, M.; Peña, I.; Perez, C.; Blanco, S.; Sanz, M. E.; Lopez, J. C.; Alonso, J. L.

    2011-05-01

    Microwave spectroscopy, considered the most definitive gas phase structural probe, can distinguish between different conformational structures since they have unique spectroscopic constants and give separate rotational spectra. However it has been limited to molecular specimens having an appreciable vapor pressure. In general, molecules of biological importance have low vapor pressures and tend to undergo degradation upon heating. The combination of laser ablation with Fourier transform microwave spectroscopy in supersonic jets (LA-MB-FTMW) which overcomes the problems of thermal decomposition has rendered accessible the gas phase structural studies of these molecules. To date different α-, β- and γ-amino acids have been studied using this technique. Even in conformationally challenging systems the preferred conformations can be identified by rotational spectroscopy, as has been illustrated with the assignment of seven low-energy conformers in serine and threonine, six in cysteine and aspartic acid , and nine in γ-amino butyric (gaba). This technique has been successfully applied to the study of monosaccarides. Three conformers of the prototypes α-D-glucose and β-D-glucose have been characterized for the first time in the gas phase. After the first experimental observation of the monohydrated cluster of glycine, complexes between amino acids and nitrogen bases with water have also been investigated to obtain information on the changes induced in the conformational or tautomeric preferences by the addition of solvent molecules. The information given here is relevant for the unambiguous identification of these amino acids and sugars in the interstellar medium.

  2. Ammonia Gas Sensing Behavior of Tanninsulfonic Acid Doped Polyaniline-TiO2 Composite

    Directory of Open Access Journals (Sweden)

    Venu Gopal Bairi

    2015-10-01

    Full Text Available A highly active tannin doped polyaniline-TiO2 composite ammonia gas sensor was developed and the mechanism behind the gas sensing activity was reported for the first time. A tanninsulfonic acid doped polyaniline (TANIPANI-titanium dioxide nanocomposite was synthesized by an in situ polymerization of aniline in the presence of tanninsulfonic acid and titanium dioxide nanoparticles. X-ray diffraction and thermogravimetric analysis were utilized to determine the incorporation of TiO2 in TANIPANI matrix. UV-Visible and infrared spectroscopy studies provided information about the electronic interactions among tannin, polyaniline, and TiO2. Scanning electron microscopy (SEM along with energy dispersive X-ray spectroscopy (EDS and atomic force microscopy (AFM surface analysis techniques were used to investigate the metal oxide dispersions inside polyaniline matrix. Gas sensors were prepared by spin coating solutions of TANIPANI-TiO2 and TANIPANI composites onto glass slides. Sensors were tested at three different concentrations (20 ppm, 40 ppm, and 60 ppm of ammonia gas at ambient temperature conditions by measuring the changes in surface resistivity of the films with respect to time. Ammonia gas sensing plots are presented showing the response values, response times and recovery times. The TANIPANI-TiO2 composite exhibited better response and shorter recovery times when compared to TANIPANI control and other polyaniline composites that have been reported in the literature. For the first time a proposed mechanism of gas sensing basing on the polaron band localization and its effects on the gas sensing behavior of polyaniline are reported.

  3. Gas chromatography-mass spectrometry profiles of urinary organic acids in healthy captive cheetahs (Acinonyx jubatus).

    Science.gov (United States)

    Tordiffe, Adrian Stephen Wolferstan; van Reenen, Mari; Reyers, Fred; Mienie, Lodewyk Jacobus

    2017-04-01

    In captivity, cheetahs (Acinonyx jubatus) frequently suffer from several unusual chronic diseases that rarely occur in their free-ranging counterparts. In order to develop a better understanding of their metabolism and health we documented the urine organic acids of 41 apparently healthy captive cheetahs, in an untargeted metabolomic study, using gas chromatography-mass spectrometry. A total of 339 organic acids were detected and annotated. Phenolic compounds, thought to be produced by the anaerobic fermentation of aromatic amino acids in the distal colon, as well as their corresponding glycine conjugates, were present in high concentrations. The most abundant organic acids in the cheetahs' urine were an as yet unidentified compound and a novel cadaverine metabolite, tentatively identified as N(1),N(5)-dimethylpentane-1,5-diamine. Pantothenic acid and citramalic acid concentrations correlated negatively with age, while glutaric acid concentrations correlated positively with age, suggesting possible dysregulation of coenzyme A metabolism in older cheetahs. This study provides a baseline of urine organic acid reference values in captive cheetahs and suggests important avenues for future research in this species.

  4. Identification of 19 phthalic acid esters in dairy products by gas chromatography with mass spectrometry.

    Science.gov (United States)

    Wu, Pinggu; Cai, Chenggang; Yang, Dajin; Wang, Liyuan; Zhou, Yan; Shen, Xianghong; Ma, Bingjie; Tang, Jun

    2015-01-01

    A detection method for 19 kinds of phthalic acid ester compounds analyzed by n-hexane/ether/acetonitrile 1:7:8 v/v/v mixed solvent extraction, quick, easy, cheap, effective, rugged, and safe purification and internal standard method of quantitative gas chromatography with mass spectrometry was established. This method can effectively remove interfering materials, such as lipids, fatty acids, and pigments, from dairy products. The 19 kinds of phthalic acid ester compounds were within a 0.025-0.2 mg/kg range, the recovery rate was 65.2-125.7%, relative standard deviation was 7.9-15.4% (n = 6), and the limit of detection was 0.005-0.02 mg/kg. Concentrations of the 19 kinds of phthalic acid ester compounds ranged between 0.01 and 0.12 mg/kg in ten dairy materials and 20 dairy products. The established method is simple, rapid, accurate, and highly sensitive.

  5. Example of health hazard: people killed by gas during a phreatic eruption: Dieng Plateau (Java, Indonesia), February 20th 1979

    Energy Technology Data Exchange (ETDEWEB)

    Le Guern, F. (Lab. mixte CNRS-CEA, Yvette, France); Tazieff, H.; Faivre Pierret, R.

    1982-01-01

    On February 20th, 1979, 142 inhabitants of Dieng Plateau (Indonesia) were asphyxiated by poisonous gases during a mild phreatic eruption. From later fields gas collection and analysis, the casualties are considered to be due to CO/sub 2/ rich volcanic gases.

  6. Thermal decarboxylation of acetic acid: Implications for origin of natural gas

    Science.gov (United States)

    Kharaka, Y.K.; Carothers, W.W.; Rosenbauer, R.J.

    1983-01-01

    Laboratory experiments on the thermal decarboxylation of solutions of acetic acid at 200??C and 300??C were carried out in hydrothermal equipment allowing for on-line sampling of both the gas and liquid phases for chemical and stable-carbon-isotope analyses. The solutions had ambient pH values between 2.5 and 7.1; pH values and the concentrations of the various acetate species at the conditions of the experiments were computed using a chemical model. Results show that the concentrations of acetic acid, and not total acetate in solution, control the reaction rates which follow a first order equation based on decreasing concentrations of acetic acid with time. The decarboxylation rates at 200??C (1.81 ?? 10-8 per second) and 300??C (8.17 ?? 10-8 per second) and the extrapolated rates at lower temperatures are relatively high. The activation energy of decarboxylation is only 8.1 kcal/mole. These high decarboxylation rates, together with the distribution of short-chained aliphatic acid anions in formation waters, support the hypothesis that acid anions are precursors for an important portion of natural gas. Results of the ??13C values of CO2, CH4, and total acetate show a reasonably constant fractionation factor of about 20 permil between CO2 and CH4 at 300??C. The ??13C values of CO2 and CH4 are initially low and become higher as decarboxylation increases. ?? 1983.

  7. Quantitation of homovanillic acid (HVA) and vanillylmandelic acid (VMA) in urine using gas chromatography-mass spectrometry (GC/MS).

    Science.gov (United States)

    Allenbrand, Ryan; Garg, Uttam

    2010-01-01

    Neuroblastoma, in most cases, is characterized by increased production of catecholamines and their metabolites. Laboratory diagnosis and clinical follow-up include the measurement of urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA). In the following procedure, urine samples are diluted to give a creatinine concentration of 2 mg/dL. Deuterated internal standards are added to the diluted urine samples followed by acidification using HCl. Ethyl acetate is used to extract HVA and VMA from the acidified samples, and the extract is dried. The residue is treated with bis-(trimethylsilyl)trifluoroacetamide (BSTFA), 1% trimethylchlorosilane (TMCS), and pyridine to prepare trimethylsilyl derivatives of HVA and VMA. The derivatized samples are injected to into gas-chromatograph mass spectrometer. The concentration of HVA and VMA is determined by comparing responses of unknown sample to the responses of calibrators using selected ion monitoring.

  8. Elusive Sulfurous Acid: Gas-Phase Basicity and IR Signature of the Protonated Species.

    Science.gov (United States)

    Sinha, Rajeev K; Scuderi, Debora; Maitre, Philippe; Chiavarino, Barbara; Crestoni, Maria Elisa; Fornarini, Simonetta

    2015-05-01

    The ion corresponding to protonated sulfurous acid, H3SO3(+), has been successfully delivered into the gas phase by electrospray ionization of the solution of a suitable precursor and an in-source fragmentation process. The neutral acid is a highly elusive molecule. However, its gas-phase basicity has been ascertained by means of a kinetic study of proton-transfer reactivity. The structure of the H3SO3(+) sampled ion has been probed by IRMPD spectroscopy in two complementary IR frequency ranges in conjunction with density functional theory calculations and found to conform to a trihydroxosulfonium ion. The characteristic IR signatures may aid in deciphering the presence of this species in extraterrestrial atmospheres.

  9. Hydration energies of deprotonated amino acids from gas phase equilibria measurements.

    Science.gov (United States)

    Wincel, Henryk

    2008-08-01

    Singly hydrated clusters of deprotonated amino acids were studied using an electrospray high-pressure mass spectrometer equipped with a pulsed ion-beam reaction chamber. Thermochemical data, DeltaH(o), DeltaS(o), and DeltaG(o), for the hydration reaction [AA - H](-) + H(2)O = [AA - H](-).(H(2)O) were obtained from gas-phase equilibria determinations for AA = Gly, Ala, Val, Pro, Phe, Lys, Met, Trp, Gln, Arg, and Asp. The hydration free-energy changes are found to depend significantly on the side-chain substituents. The water binding energy in [AA - H](-).(H(2)O) increases with the gas-phase acidity of AA. The anionic hydrogen bond strengths in [AA - H](-).(H(2)O) are compared with those of the cationic bonds in the corresponding AAH(+).(H(2)O) systems.

  10. Electrons Mediate the Gas-Phase Oxidation of Formic Acid with Ozone.

    Science.gov (United States)

    van der Linde, Christian; Tang, Wai-Kit; Siu, Chi-Kit; Beyer, Martin K

    2016-08-26

    Gas-phase reactions of CO3 (.-) with formic acid are studied using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Signal loss indicates the release of a free electron, with the formation of neutral reaction products. This is corroborated by adding traces of SF6 to the reaction gas, which scavenges 38 % of the electrons. Quantum chemical calculations of the reaction potential energy surface provide a reaction path for the formation of neutral carbon dioxide and water as the thermochemically favored products. From the literature, it is known that free electrons in the troposphere attach to O2 , which in turn transfer the electron to O3 . O3 (.-) reacts with CO2 to form CO3 (.-) . The reaction reported here formally closes the catalytic cycle for the oxidation of formic acid with ozone, catalyzed by free electrons.

  11. Determination of phenoxy acid herbicides in water by electron-capture and microcoulometric gas chromatography

    Science.gov (United States)

    Goerlitz, D.F.; Lamar, William L.

    1967-01-01

    A sensitive gas chromatographic method using microcoulometric titration and electron-capture detection for the analysis of 2,4-D, silvex, 2,4,5-T, and other phenoxy acid herbicides in water is described. The herbicides are extracted from unfiltered water samples (800-1,000 ml) by use of ethyl ether ; then the herbicides are concentrated and esterilied. To allow the analyst a choice, two esterilication procedures--using either boron trifluoride-methanol or diazomethane--are evaluated. Microcoulometric gas chromatography is specific for the detection of halogenated compounds such as the phenoxy acid herbicides whereas it does not respond to nonhalogenated components. Microcoulometric gas chromatography requires care and patience. It is not convenient for rapid screening of l-liter samples that contain less than 1 microgram of the herbicide. Although electroncapture gas chromatography is less selective and more critically affected by interfering substances, it is, nevertheless, convenient and more sensitive than microcoulometric gas chromatography. Two different liquid phases are used in the gas chromatographic columns--DC-200 silicone in one column and QF-1 silicone in the other. The performance of both columns is improved by the addition of Carbowax 20M. The Gas Chrom Q support is coated with the liquid phases by the 'frontal-analysis' technique. The practical lower limits for measurement of the phenoxy acid herbicides in water primarily depend upon the sample size, interferences present, anal instrumentation used. With l-liter samples of water, the practical lower limits of measurement are 10 ppt (parts per trillion) for 2,4-D and 2 ppt for silvex and 2,4,5-T when electron-capture detection is used, and approximately 20 ppt for each herbicide when analyzed by microcoulometric-titration gas chromatography. Recoveries of the herbicides immediately after addition to unfiltered water samples averaged 92 percent for 2,4-D, 90 percent for silvex, and 98 percent for 2

  12. Gas chromatographic/mass spectrometric determination of lysergic acid diethylamide (LSD) in serum samples.

    Science.gov (United States)

    Musshoff, F; Daldrup, T

    1997-08-04

    A sensitive method for the detection and quantification of lysergic acid diethylamide (LSD) in serum samples is described. After liquid-liquid extraction the trimethylsilyl derivative of LSD is detected by gas chromatography-mass spectrometry. Experiments with spiked samples resulted in a recovery of 76%, the coefficient of variation was 9.3%. Excellent linearity was obtained over the range 0.1-10 ng ml-1. Additionally experiments demonstrating the light sensitivity of LSD are presented together with casuistics.

  13. Continuous method to remove acid gases from a gas mixture supply

    Energy Technology Data Exchange (ETDEWEB)

    Butwell, K.F.; Kubek, D.J.

    1979-07-05

    It is proposed to remove acid gases - particularly CO/sub 2/ - from process gases (e.g. hydrocarbon mixtures, synthesis gas) by counter-current absorption with alcohol amines, to use monoethanol amine to which antimony and vanadium compounds are added as corrosion inhibitors. The patent claim includes a combination of 11 process steps, whose aim is to reduce the necessity of heating and cooling by external sources to a minimum. The method is described in detail.

  14. Characterization of 22 Vibrio species by gas chromatography analysis of their cellular fatty acids.

    Science.gov (United States)

    Urdaci, M C; Marchand, M; Grimont, P A

    1990-05-01

    The cellular fatty acid compositions of 51 Vibrio strains belonging to 22 species as well as five Aeromonas strains were determined by using capillary gas-liquid chromatography (GLC). The major fatty acids were most often hexadecenoic, hexadecanoic and octadecenoic acids. Heptadecenoic acid was present in significant amounts in V. alginolyticus, V. natriegens, V. parahaemolyticus and "Vibrio navarrensis". Twenty fatty acids including branched and hydroxy acids were detected in the genus Vibrio. Quantitative results were treated by principal component analysis to display groups of strains. The first three components (accounting for 69% of the variance) showed the type strains of V. fischeri, V. ordalii, V. damsela, V. mediterranei, V. tubiashii, V. campbellii, V. pelagius, V. gazogenes, and V. nereis to be unclustered. V. alginolyticus (4 strains) and V. parahaemolyticus (4 strains) showed some overlap and the type strain of V. natriegens was in their neighborhood. V. harveyi (4 strains) formed a cluster and V. vulnificus was in its vicinity. V. cholerae (5 strains) overlapped with V. diazotrophicus (3 strains) and was close to the type strain of V. mimicus and V. anguillarum. V. metschnikovii (3 strains) clustered with the type strain of V. cincinnatiensis. A decision tree was devised for the identification of Vibrio species based on qualitative characteristics of fatty acid patterns. However, the following three groups, V. alginolyticus-V. parahaemolyticus-V. natriegens, V. metschnikovii-V. cincinnatiensis and V. cholerae-V. mimicus could not be split into such a decision tree.

  15. Identification and hazard prediction of tattoo pigments by means of pyrolysis—gas chromatography/mass spectrometry

    OpenAIRE

    2016-01-01

    The implementation of regulation for tattoo ink ingredients across Europe has generated the need for analytical methods suitable to identify prohibited compounds. Common challenges of this subject are the poor solubility and the lack of volatility for most pigments and polymers applied in tattoo inks. Here, we present pyrolysis coupled to online gas chromatography and electron impact ionization mass spectrometry (py-GC/MS) as quick and reliable tool for pigment identification using both purif...

  16. Gas/particle partitioning of PCDD/Fs in flue gas of hazardous waste incinerator%危险废物焚烧炉烟气中二恶英气固相分配

    Institute of Scientific and Technical Information of China (English)

    姬亚; 陆胜勇; 林晓青; 李晓东; 严建华

    2012-01-01

    The partitioning of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/ Fs) between gas and solid phase in the flue gas of a hazardous waste incinerator was analyzed. Results show that, gas/particle partitioning of PCDD/Fs at the inlet of baghouse filter is as follows: gas/particle value is 62/38 according to the mass fraction, while it is 76/24 according to the I-TEQ concentration value. The fraction of gas phase PCDD/F congeners decreases with rising chlorination, i. e. highly chlorinated congeners have higher tendencies to attach to the fly ash, while lowly chlorinated congeners occupy a larger fraction of the gas phase. The fractions of gas phase congeners are roughly but not accurately in line with the vapor pressures, which indicates that vapor pressure is one of the main factors to determine the gas/particle partitioning of PCDD/F congeners in flue gas.%研究某危险废物焚烧炉烟气中二恶英气固相分配特征.结果表明,布袋除尘器入口烟气中二恶英气固相分配如下:气相二恶英的质量分数平均为62%,固相为38%;气相的毒性当量质量分数平均为76%,固相为24%.各异构体气相质量分数(即每个异构体气相部分质量浓度占该异构体气、固相总质量浓度的百分比)随氯代数的增加而降低,即高氯代异构体更多地附着于飞灰上,低氯代异构体则更多地分布于气相中;气相质量分数的变化趋势基本与蒸汽压相符,表明蒸汽压是决定焚烧烟气中二恶英各异构体气固相分配的主要因素之一.

  17. Investigation of secondary formation of formic acid: urban environment vs. oil and gas producing region

    Science.gov (United States)

    Yuan, B.; Veres, P. R.; Warneke, C.; Roberts, J. M.; Gilman, J. B.; Koss, A.; Edwards, P. M.; Graus, M.; Kuster, W. C.; Li, S.-M.; Wild, R. J.; Brown, S. S.; Dubé, W. P.; Lerner, B. M.; Williams, E. J.; Johnson, J. E.; Quinn, P. K.; Bates, T. S.; Lefer, B.; Hayes, P. L.; Jimenez, J. L.; Weber, R. J.; Zamora, R.; Ervens, B.; Millet, D. B.; Rappenglück, B.; de Gouw, J. A.

    2015-02-01

    Formic acid (HCOOH) is one of the most abundant carboxylic acids in the atmosphere. However, current photochemical models cannot fully explain observed concentrations and in particular secondary formation of formic acid across various environments. In this work, formic acid measurements made at an urban receptor site (Pasadena) in June-July 2010 during CalNex (California Research at the Nexus of Air Quality and Climate Change) and a site in an oil and gas producing region (Uintah Basin) in January-February 2013 during UBWOS 2013 (Uintah Basin Winter Ozone Studies) will be discussed. Although the VOC (volatile organic compounds) compositions differed dramatically at the two sites, measured formic acid concentrations were comparable: 2.3 ± 1.3 in UBWOS 2013 and 2.0 ± 1.0 ppb in CalNex. We determine that concentrations of formic acid at both sites were dominated by secondary formation (> 99%). A constrained box model using the Master Chemical Mechanism (MCM v3.2) underestimates the measured formic acid concentrations drastically at both sites (by a factor of > 10). Compared to the original MCM model that includes only ozonolysis of unsaturated organic compounds and OH oxidation of acetylene, when we updated yields of ozonolysis of alkenes and included OH oxidation of isoprene, vinyl alcohol chemistry, reaction of formaldehyde with HO2, oxidation of aromatics, and reaction of CH3O2 with OH, the model predictions for formic acid were improved by a factor of 6.4 in UBWOS 2013 and 4.5 in CalNex, respectively. A comparison of measured and modeled HCOOH/acetone ratios is used to evaluate the model performance for formic acid. We conclude that the modified chemical mechanism can explain 19 and 45% of secondary formation of formic acid in UBWOS 2013 and CalNex, respectively. The contributions from aqueous reactions in aerosol and heterogeneous reactions on aerosol surface to formic acid are estimated to be 0-6 and 0-5% in UBWOS 2013 and CalNex, respectively. We observe that

  18. Gas emission from diffuse degassing structures (DDS) of the Cameroon volcanic line (CVL): Implications for the prevention of CO2-related hazards

    Science.gov (United States)

    Issa; Ohba, T.; Chako Tchamabé, B.; Padrón, E.; Hernández, P.; Eneke Takem, E. G.; Barrancos, J.; Sighomnoun, D.; Ooki, S.; Nkamdjou, Sigha; Kusakabe, M.; Yoshida, Y.; Dionis, S.

    2014-08-01

    In the mid-1980s, lakes Nyos and Monoun violently released massive gas, mainly magmatic CO2 killing about 1800 people. Subsequent geochemical surveys and social studies indicate that lakes Nyos and Monoun event is cyclic in nature and may occur anywhere in the about 37 other volcanic lakes located in the corridor of the Cameroon volcanic line (CVL). This potential threat motivated us to check if, alike Nyos and Monoun, the internal dynamic of the other lakes is also controlled by inputs of deep-seated-derived CO2 and attempt to measure and provide comprehensive insights on the passive gas emission along the CVL. This knowledge shall contribute to the prevention of volcanic lake-related hazards in Cameroon and the refinement of the Global Carbon Cycle. We used in situ fixation and dry gas phase sampling methods to determine CO2 origin and the concentration, and the accumulation chamber technique to measure diffuse CO2 emission from nine lakes and on soil at Nyos Valley and Mount Manenguba Caldera. The results suggest that, although in minor concentrations (compared to Nyos and Monoun), ranging from 0.56 mmol kg- 1 to 8.75 mmol kg- 1, the bottom waters of some lakes also contain measurable magmatic CO2 with δ13C varies from - 4.42‰ to - 9.16‰ vs. PDB. That finding implies that, under certain circumstances, e.g. increase to volcanic and/or tectonic activities along the CVL, the concerned lakes could develop a Nyos-type behavioural scheme. The diffuse gas emission results indicate that the nine surveyed lakes release approximately 3.69 ± 0.37 kt km- 2 yr- 1 of CO2 to the atmosphere; extrapolation to the approximately 39 volcanic lakes located on the CVL yields an approximate CO2 output of 27.37 ± 0.5 kt km- 2 yr- 1, representing 0.023% of the global CO2 output from volcanic lakes. In addition to the precedent value, the gas removal operation in lakes Nyos and Monoun released approximately 2.52 ± 0.46 × 108 mol km- 2 yr- 1 CO2 to the atmosphere from January

  19. Ammonia Gas Detection by Tannic Acid Functionalized and Reduced Graphene Oxide at Room Temperature

    Directory of Open Access Journals (Sweden)

    Sweejiang Yoo

    2014-01-01

    Full Text Available Reduced graphene oxide (rGO based chemiresistor gas sensor has received much attention in gas sensing for high sensitivity, room temperature operation, and reversible. Here, for the first time, we present a promising chemiresistor for ammonia gas detection based on tannic acid (TA functionalized and reduced graphene oxide (rGOTA functionalized. Green reductant of TA plays a major role in both reducing process and enhancing the gas sensing properties of rGOTA functionalized. Our results show rGOTA functionalized only selective to ammonia with excellent respond, recovery, respond time, and recovery times. rGOTA functionalized electrical resistance decreases upon exposure to NH3 where we postulated that it is due to n-doping by TA and charge transfer between rGOTA functionalized and NH3 through hydrogen bonding. Furthermore, rGOTA functionalized hinders the needs for stimulus for both recovery and respond. The combination of greener sensing material and simplicity in overall sensor design provides a new sight for green reductant approach of rGO based chemiresistor gas sensor.

  20. Supramolecular Adducts of Cucurbit[7]uril and Amino Acids in the Gas Phase

    Science.gov (United States)

    Kovalenko, Ekaterina; Vilaseca, Marta; Díaz-Lobo, Mireia; Masliy, A. N.; Vicent, Cristian; Fedin, Vladimir P.

    2016-02-01

    The complexation of the macrocyclic cavitand cucurbit[7]uril (Q7) with a series of amino acids (AA) with different side chains (Asp, Asn, Gln, Ser, Ala, Val, and Ile) is investigated by ESI-MS techniques. The 1:1 [Q7 + AA + 2H]2+ adducts are observed as the base peak when equimolar Q7:AA solutions are electrosprayed, whereas the 1:2 [Q7 + 2AA + 2H]2+ dications are dominant when an excess of the amino acid is used. A combination of ion mobility mass spectrometry (IM-MS) and DFT calculations of the 1:1 [Q7 + AA + 2H]2+ (AA = Tyr, Val, and Ser) adducts is also reported and proven to be unsuccessful at discriminating between exclusion or inclusion-type conformations in the gas phase. Collision induced dissociation (CID) revealed that the preferred dissociation pathways of the 1:1 [Q7 + AA + 2H]2+ dications are strongly influenced by the identity of the amino acid side chain, whereas ion molecule reactions towards N-butylmethylamine displayed a common reactivity pattern comprising AA displacement. Special emphasis is given on the differences between the gas-phase behavior of the supramolecular adducts with amino acids (AA = Asp, Asn, Gln, Ser, Ala, Val, and Ile) and those featuring basic (Lys and Arg) and aromatic (Tyr and Phe) side chains.

  1. Pentafluorobenzyl esterification of haloacetic acids in tap water for simple and sensitive analysis by gas chromatography/mass spectrometry with negative chemical ionization.

    Science.gov (United States)

    Zhao, Can; Fujii, Yukiko; Yan, Junxia; Harada, Kouji H; Koizumi, Akio

    2015-01-01

    Chlorine is the most widely used disinfectant for control of waterborne diseases in drinking water treatment. It can react with natural organic matter in water and form haloacetic acids (HAAs). For analysis of HAA levels, derivatization with diazomethane is commonly recommended as the standard methodology in Japan. However, diazomethane is a carcinogenic alkylating agent. Therefore, in this study, a safe, simple, and sensitive quantification method was developed to monitor HAAs in drinking water. Pentafluorobenzyl esterification was used for pretreatment. The pentafluorobenzyl-ester derivative was detected by gas chromatography-negative ion chemical ionization-mass spectrometry analysis with very high sensitivity for HAAs analysis. The method has low detection limits (8-94 ng L(-1)) and good recovery rates (89-99%) for HAAs. The method was applied to 30 tap water samples from 15 cities in the Kansai region of Japan. The levels of HAAs detected were in the range 0.54-7.83 μg L(-1). Dichloroacetic acid, trichloroacetic acid, and bromochloroacetic acid were the major HAAs detected in most of the tap water, and accounted for 29%, 20% and 19% of the total HAAs, respectively. This method could be used for routine monitoring of HAAs in drinking water without exposure of workers to occupational hazards.

  2. Surface Lewis acid-base properties of polymers measured by inverse gas chromatography.

    Science.gov (United States)

    Shi, Baoli; Zhang, Qianru; Jia, Lina; Liu, Yang; Li, Bin

    2007-05-18

    Surface Lewis acid-base properties are significant for polymers materials. The acid constant, K(a) and base constant, K(b) of many polymers were characterized by some researchers with inverse gas chromatography (IGC) in recent years. In this paper, the surface acid-base constants, K(a) and K(b) of 20 kinds of polymers measured by IGC in recent years are summarized and discussed, including seven polymers characterized in this work. After plotting K(b) versus K(a), it is found that the polymers can be encircled by a triangle. They scatter in two regions of the triangle. Four polymers exist in region I. K(b)/K(a) of the polymers in region I are 1.4-2.1. The other polymers exist in region II. Most of the polymers are relative basic materials.

  3. SO2 gas adsorption by modified kaolin clays: influence of previous heating and time acid treatments.

    Science.gov (United States)

    Volzone, Cristina; Ortiga, Jose

    2011-10-01

    Modified kaolin clays were used as adsorbents for SO(2) gas adsorptions. The clays were heated up to 900 °C previous to acid treatments with 0.5 N sulfuric acid solutions at boiling temperature during different times up to 1440 min. Equilibrium adsorption at 25 °C and 0.1 MPa was carried out by using a volumetric apparatus. The samples were characterized by chemical analysis, X-ray diffraction and infrared analysis. The heating of the clays followed by acid treatment improved the adsorption capacity of the kaolin clays. The presence of amorphous silica and hydroxyl in the final products improved SO(2) adsorption capacity. Better properties for SO(2) adsorption were found in kaolin rich in not well ordered kaolinite clay mineral.

  4. Determination of major phenolic acids, phenolic diterpenes and triterpenes in Rosemary (Rosmarinus Officinalis L.) by gas chromatography and mass spectrometry:

    OpenAIRE

    Vončina, Ernest; Doleček, Valter; Islamčević Razboršek, Maša; Brodnjak-Vončina, Darinka

    2007-01-01

    A gas chromatographic-mass spectrometric (GC-MS) method for the simultaneous identification and quantification of seven major phenolic and terpenic compounds in Rosmarinus officinalis L. was developed. The compounds were identified as trimethylsilyl (TMS) derivatives of phenolic acids (caffeic and rosmarinic acid), phenolic diterpene (carnosic acid), and pentacyclic triterpenes (ursolic, oleanolic, betulinic acid and betulin). These compounds have been identified by retention time and compari...

  5. Formation of Small Gas Phase Carbonyls from Heterogeneous Oxidation of Polyunsaturated Fatty Acids (PUFA)

    Science.gov (United States)

    Zhou, S.; Zhao, R.; Lee, A.; Gao, S.; Abbatt, J.

    2011-12-01

    Fatty acids (FAs) are emitted into the atmosphere from gas and diesel powered vehicles, cooking, plants, and marine biota. Field measurements have suggested that FAs, including polyunsaturated fatty acids (PUFA), could make up an important contribution to the organic fraction of atmospheric aerosols. Due to the existence of carbon-carbon double bonds in their molecules, PUFA are believed to be highly reactive towards atmospheric oxidants such as OH and NO3 radicals and ozone, which will contribute to aerosol hygroscopicity and cloud condensation nuclei activity. Previous work from our group has shown that small carbonyls formed from the heterogeneous reaction of linoleic acid (LA) thin films with gas-phase O3. It is known that the formation of small carbonyls in the atmosphere is not only relevant to the atmospheric budget of volatile organic compounds but also to secondary organic aerosol formation. In the present study, using an online proton transfer reaction mass spectrometry (PTR-MS) and off-line gas chromatography-mass spectrometry (GC-MS) we again investigated carbonyl formation from the same reaction system, i.e. the heterogeneous ozonolysis of LA film. In addition to the previously reported carbonyls, malondialdehyde (MDA), a source of reactive oxygen species that is mutagenic, has been identified as a product for the first time. Small dicarbonyls, e.g. glyoxal, are expected to be formed from the further oxidation of MDA. In this presentation, the gas-phase chemistry of MDA with OH radicals using a newly built Teflon chamber in our group will also be presented.

  6. An optimized method for fatty acid analysis, including quantification of trans fatty acids, in human adipose tissue by gas-liquid chromatography

    DEFF Research Database (Denmark)

    Bysted, Anette; Cold, S; Hølmer, Gunhild Kofoed

    1999-01-01

    Considering the need for a quick direct method for measurement of the fatty acid composition including trans isomers ofhuman adipose tissue we have developed a procedure using gas-liquid chromatography (GLC) alone, which is thussuitable for validation of fatty acid status in epidemiological studies...

  7. Synthesis of hierarchical SnO2 nanoflowers with enhanced acetic acid gas sensing properties

    Science.gov (United States)

    Jin, W. X.; Ma, S. Y.; Tie, Z. Z.; Li, W. Q.; Luo, J.; Cheng, L.; Xu, X. L.; Wang, T. T.; Jiang, X. H.; Mao, Y. Z.

    2015-10-01

    Different morphologies hierarchical flower-like tin dioxide (SnO2) nanostructures were fabricated by changing the volume ratio of glycol and de-ionized water (Vg:Vw = 0, 1:2, 1:1 and 2:1) under a template-free and low-cost hydrothermal method and subsequent calcinations. The architectures, morphologies and gas sensing performances of the products were characterized by X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and gas-sensing measurement device. It can be observed that all the nanoflowers were composed of two-dimensional (2D) nanosheets, and the thickness of nanosheets is only about 9 nm when Vg:Vw = 1:1. The sensor based on the product of Vg:Vw = 1:1 exhibited excellent gas sensing performance toward 500 ppm acetic acid at 260 °C, and the response value of this sensor was about 153.6, which was above 7.5 times higher than that of ammonia (about 20.3). In addition, the 3D flower-like SnO2 nanostructures exhibited not only high response and selectivity to ppm level acetone, but also fast response and recovery time within 10 s, demonstrating it can be used as a potential candidate for detecting acetic acid. Finally, the possible formation mechanism was proposed, too.

  8. Assessment of DFT methods for studying acid gas capture by ionic liquids.

    Science.gov (United States)

    García, Gregorio; Atilhan, Mert; Aparicio, Santiago

    2015-10-28

    For the first time, this work reports an analysis of the performance of Density Functional methods for studying acid gas capture (CO2 and SO2) by ionic liquids (ILs). The considered functionals were selected as representatives of the available families: pure GGA (PBE and BLYP), hybrid (PBE0 and B3LYP), hybrid meta-GGA (M06, M06-2X and M06-HF), long range corrected (LC-PBEPBE, CAM-B3LYP, ωB97X) and dispersion corrected (PBE-D2, B3LYP-D2 and ωB97XD). Likewise, HF and MP2 were also applied. Binding energies of cation-anion interacting pairs as well as IL-CO2 and IL-SO2 systems were calculated for a set of 54 ILs and compared against MP2/aug-cc-pvDZ. Unlike previously reported DFT benchmarks on ILs, which calculated binding energies through single point calculations on fixed geometries, properties in this work were calculated for geometries optimized at each theoretical level. DFT functionals that are suitable for describing ion-ion and ion-gas interactions were identified, considering both Coulombic forces and dispersion interactions. The reported results allowed us to infer relationships to the rational design of ILs for acid gas capture.

  9. ELECTRIC POWER GENERATION USING A PHOSPHORIC ACID FUEL CELL ON A MUNICIPAL SOLID WASTE LANDFILL GAS STREAM

    Science.gov (United States)

    The report gives results of tests to verify the performance of a landfill gas pretreatment unit (GPU) and a phorsphoric acid fuel cell system. The complete system removes contaminants from landfill gas and produces electricity for on-site use or connection to an electric grid. Th...

  10. Are cyclopentadienylberyllium, magnesium and calcium hydrides carbon or metal acids in the gas phase?

    Science.gov (United States)

    Hurtado, Marcela; Lamsabhi, Al-Mokhtar; Mó, Otilia; Yáñez, Manuel; Guillemin, Jean-Claude

    2010-05-21

    The structure and bonding of cyclopentadienylberyllium (CpBeH), magnesium (CpMgH), and calcium (CpCaH) hydrides as well as those of their deprotonated species have been investigated by means of B3LYP/6-311+G(3df,2p)//B3LYP/6-311+G(d,p) and B3LYP/6-311+G(3df,2p)//QCISD/6-311+G(d,p) density functional theory (DFT) calculations. The three compounds exhibit C(5v) equilibrium conformations in their ground states. For CpBeH the agreement between the calculated geometry and that determined by MW spectroscopy is excellent. CpMgH and CpCaH can be viewed almost as the result of the interaction between a C₅H₅⁻ anion and a XH(+) (X = Mg, Ca) cation. Conversely, for CpBeH the interaction between the C₅H₅ and the BeH subunits is significantly covalent. These compounds exhibit a significant aromaticity, usually named three-dimension aromaticity, in contrast with the unsubstituted cyclopentadiene compound. The CpBeH derivative behaves as a C acid in the gas phase and is less acidic than cyclopentadiene. More importantly, CpMgH and CpCaH, in spite of the X(+δ)H(-δ) polarity exhibited by the X-H bond in the neutral systems, are predicted to be metal acids in the gas phase. Also surprisingly, both the Mg and the Ca derivatives are stronger acids than the Be analogue, and only slightly weaker acids than cyclopentadiene. This somewhat unexpected result is the consequence of two concomitant facts: the lower dissociation energy of the X-H (X = Mg, Ca) bonds with respect to the C-H bonds, and the significantly high electron affinity of the C₅H₅X* (X = Mg, Ca) radicals.

  11. Economic and emission accounting for acid-gas injection projects : an example from KeySpan Brazeau River, Alberta, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, R. [KeySpan Energy Canada, Calgary, AB (Canada); Wong, S.; Gunter, W.D. [Alberta Research Council, Edmonton, AB (Canada); Wichert, E. [Sogapro Engineering, Calgary, AB (Canada); McCulloch, M. [Pembina Inst., Calgary, AB (Canada)

    2005-07-01

    The Claus process has been used to treat the sour gas at the Brazeau River gas plant located 250 km southwest of Edmonton, Alberta since 1969, with a minimum sulphur requirement of 92.1 per cent. The process converts sulphur compounds to elemental sulphur, which can then be sold or stockpiled, while the residual carbon dioxide (CO{sub 2}) is vented to the atmosphere. A SuperClaus sulphur recovery process can be added to the Claus process to convert even more residual sulphur that remains in the acid gas after having passed through the Claus beds. However, given the current low price of sulphur, the cost of sulphur recovery exceeds the value of the sulphur. Another option would be to inject the acid gas, CO{sub 2} and hydrogen sulphide (H{sub 2}S), into the Nisku Q Pool, a depleted gas reservoir. The economic merits and emission characteristics of the two options were compared on a life cycle basis, with particular reference to an AGI operation at the KeySpan Brazeau River gas plant, Alberta. AGI involves compressing the acid gas and injecting it into a suitable underground zone, similar to deep well disposal of produced water. Although the purpose of the AGI operations is to dispose of the H{sub 2}S, significant quantities of CO{sub 2} are being injected at the same time. The injection of acid gas into a depleted gas reservoir would eliminate sulphur dioxide (SO{sub 2}) emissions at the plant site, increase plant efficiency, lower capital and life-cycle costs, extend plant life and employment. The Brazeau River Acid-Gas Injection Project effectively deals with the proactive de-grandfathering of sulphur recovery gas plants and reduction of greenhouse gas emissions to the atmosphere. It was concluded that acid-gas injection at Brazeau is cost effective. The current scheme would generate a breakeven sulphur price of at least $15.5/t net of transportation cost. Obtaining CO{sub 2} credits for CO{sub 2} storage in acid-gas injection operation was shown to be feasible

  12. Synthesis of Fe Nanoparticles Functionalized with Oleic Acid Synthesized by Inert Gas Condensation

    Directory of Open Access Journals (Sweden)

    L. G. Silva

    2014-01-01

    Full Text Available In this work, we study the synthesis of monodispersed Fe nanoparticles (Fe-NPs in situ functionalized with oleic acid. The nanoparticles were self-assembled by inert gas condensation (IGC technique by using magnetron-sputtering process. Structural characterization of Fe-NPs was performed by transmission electron microscopy (TEM. Particle size control was carried out through the following parameters: (i condensation zone length, (ii magnetron power, and (iii gas flow (Ar and He. Typically the nanoparticles generated by IGC showed diameters which ranged from ~0.7 to 20 nm. Mass spectroscopy of Fe-NPs in the deposition system allowed the study of in situ nanoparticle formation, through a quadrupole mass filter (QMF that one can use together with a mass filter. When the deposition system works without quadrupole mass filter, the particle diameter distribution is around +/−20%. When the quadrupole is in line, then the distribution can be reduced to around +/−2%.

  13. Identification and hazard prediction of tattoo pigments by means of pyrolysis-gas chromatography/mass spectrometry.

    Science.gov (United States)

    Schreiver, Ines; Hutzler, Christoph; Andree, Sarah; Laux, Peter; Luch, Andreas

    2016-07-01

    The implementation of regulation for tattoo ink ingredients across Europe has generated the need for analytical methods suitable to identify prohibited compounds. Common challenges of this subject are the poor solubility and the lack of volatility for most pigments and polymers applied in tattoo inks. Here, we present pyrolysis coupled to online gas chromatography and electron impact ionization mass spectrometry (py-GC/MS) as quick and reliable tool for pigment identification using both purified pigments and tattoo ink formulations. Some 36 organic pigments frequently used in tattoo inks were subjected to py-GC/MS with the aim to establish a pyrogram library. To cross-validate pigment identification, 28 commercially available tattoo inks as well as 18 self-made pigment mixtures were analyzed. Pyrograms of inks and mixtures were evaluated by two different means to work out the most reliable and fastest strategy for an otherwise rather time-consuming data review. Using this approach, the declaration of tattoo pigments currently used on the market could be verified. The pyrolysis library presented here is also assumed suitable to predict decomposition patterns of pigments when affected by other degradation scenarios, such as sunlight exposure or laser irradiation. Thus, the consumers' risk associated with the exposure to toxicologically relevant substances that originate from pigment decomposition in the dermal layers of the skin can be assessed. Differentiation between more or less harmful pigments for this field of application now will become feasible.

  14. Oil/gas pre-treatment plants and air quality hazards: PM1 measurements in Agri Valley (southern Italy

    Directory of Open Access Journals (Sweden)

    S. Trippetta

    2014-04-01

    Full Text Available A PM1 (i.e., aerosol particles with aerodynamic diameter less 1.0 μm short term monitoring campaign was carried out in Agri Valley (southern Italy in September 2012. This area is of international concern since it houses the largest European on-shore reservoir and the largest oil/gas pre-treatment plant (i.e., Centro Olio Val d'Agri – COVA within an anthropized context. PM1 measurements were performed in Viggiano, the nearest town to the COVA plant and one of the most populated town of the Agri Valley. During the study period, the PM1 daily concentrations ranged from 1.2 to 8.4 μg m−3 with a mean value of 4.6 μg m−3. Regarding the PM1 chemical composition, it can be observed that S and typical crustal elements were the most abundant constituents of the PM1 collected. By applying the Principal Component Analysis, it was pointed out that crustal soil, biomass and wood burning, secondary atmospheric reactions involving COVA plant emissions and local soil particles, and traffic were the main sources contributing to the PM1 measured in the area under study. Moreover, a possible contribution of the long-range transport of African dust was observed.

  15. Area risk level classification for hazardous gas release in petroleum refining installations%炼油装置有害气体泄漏区域风险等级划分

    Institute of Scientific and Technical Information of China (English)

    章博; 王磊; 王志刚

    2015-01-01

    The prediction results obtained from simulation of typical release scenarios for petroleum refining installations have difficulties in reflecting the real risk of hazardous gas release. In order to solve this problem, a new method of area risk level classification for hazardous gas release was proposed. It combines wind filed set and release source set to build the release scenario set and predicts the probability of each release scenario. Computational fluid dynamics ( CFD) method was used to predict the concentration field of gas leakage diffusion. Based on the leakage probability and consequences, the risk matrix of hazardous gas leakage area could be achieved. The research results indicate that the release scenario set for hazardous gas could predict the probability of each scenario quantitatively and the CFD model of hazardous gas leakage in a petroleum refi-ning installation could predict its consequence. The risk matrix of hazardous gas leakage area would provide useful reference for classifying the area risk level in petroleum refining installations.%以典型场景为代表开展的气体泄漏扩散模拟研究未能体现炼油装置的真实泄漏风险。提出一种基于泄漏场景集的炼油装置有害气体泄漏区域风险等级划分方法。融合泄漏源和风场等重要随机因素生成泄漏场景集,定量预测场景发生概率,采用计算流体力学方法( CFD)预测气体泄漏扩散体积分数场。基于场景概率和泄漏后果,得到各场景有害气体泄漏区域风险矩阵。结果表明:构建的有害气体泄漏场景集能够定量预测场景发生概率;建立的炼油装置有害气体泄漏精细CFD模型能够预测有害气体泄漏场景后果;表征各场景有害气体泄漏区域风险的区域风险矩阵可以划分符合真实情况的炼油装置有害气体泄漏区域风险等级。

  16. Acid-base and surface energy characterization of grafted polyethylene using inverse gas chromatography.

    Science.gov (United States)

    Uhlmann, Petra; Schneider, Steffen

    2002-09-06

    For a specific design of interfaces, i.e. in composites and blends, it is essential to know the surface thermodynamics of the components. Polyethylene grafted with maleic anhydride and maleic anhydride-styrene mixtures, respectively, was the component of interest of our investigations. Inverse gas chromatography (IGC) at infinite dilution was shown to be an appropriate method to evaluate the dispersive and acid-base surface characteristics although there is an influence of bulk absorption and morphology when performing IGC above the glass transition temperature of the polymer.

  17. Analysis of the citric acid cycle intermediates using gas chromatography-mass spectrometry.

    Science.gov (United States)

    Kombu, Rajan S; Brunengraber, Henri; Puchowicz, Michelle A

    2011-01-01

    Researchers view analysis of the citric acid cycle (CAC) intermediates as a metabolomic approach to identifying unexpected correlations between apparently related and unrelated pathways of metabolism. Relationships of the CAC intermediates, as measured by their concentrations and relative ratios, offer useful information to understanding interrelationships between the CAC and metabolic pathways under various physiological and pathological conditions. This chapter presents a relatively simple method that is sensitive for simultaneously measuring concentrations of CAC intermediates (relative and absolute) and other related intermediates of energy metabolism using gas chromatography-mass spectrometry.

  18. Assessment of dermal hazard from acid burns with fire retardant garments in a full-size simulation of an engulfment flash fire.

    Science.gov (United States)

    Mackay, Christopher E; Vivanco, Stephanie N; Yeboah, George; Vercellone, Jeff

    2016-09-01

    There have been concerns that fire-derived acid gases could aggravate thermal burns for individuals wearing synthetic flame retardant garments. A comparative risk assessment was performed on three commercial flame retardant materials with regard to relative hazards associated with acidic combustion gases to skin during a full engulfment flash fire event. The tests were performed in accordance with ASTM F1930 and ISO 13506: Standard Test Method for Evaluation of Flame Resistant Clothing for Protection against Fire Simulations Using an Instrumented Manikin. Three fire retardant textiles were tested: an FR treated cotton/nylon blend, a low Protex(®) modacrylic blend, and a medium Protex(®) modacrylic blend. The materials, in the form of whole body coveralls, were subjected to propane-fired flash conditions of 84kW/m(2) in a full sized simulator for a duration of either 3 or 4s. Ion traps consisting of wetted sodium carbonate-impregnated cellulose in Teflon holders were placed on the chest and back both above and under the standard undergarments. The ion traps remained in position from the time of ignition until 5min post ignition. Results indicated that acid deposition did increase with modacrylic content from 0.9μmol/cm(2) for the cotton/nylon, to 12μmol/cm(2) for the medium modacrylic blend. The source of the acidity was dominated by hydrogen chloride. Discoloration was inversely proportional to the amount of acid collected on the traps. A risk assessment was performed on the potential adverse impact of acid gases on both the skin and open wounds. The results indicated that the deposition and dissolution of the acid gases in surficial fluid media (perspiration and blood plasma) resulted in an increase in acidity, but not sufficient to induce irritation/skin corrosion or to cause necrosis in open third degree burns.

  19. Studies on Synthesis of Electrochemically Exfoliated Functionalized Graphene and Polylactic Acid/Ferric Phytate Functionalized Graphene Nanocomposites as New Fire Hazard Suppression Materials.

    Science.gov (United States)

    Feng, Xiaming; Wang, Xin; Cai, Wei; Qiu, Shuilai; Hu, Yuan; Liew, Kim Meow

    2016-09-28

    Practical application of functionalized graphene in polymeric nanocomposites is hampered by the lack of cost-effective and eco-friendly methods for its production. Here, we reported a facile and green electrochemical approach for preparing ferric phytate functionalized graphene (f-GNS) by simultaneously utilizing biobased phytic acid as electrolyte and modifier for the first time. Due to the presence of phytic acid, electrochemical exfoliation leads to low oxidized graphene sheets (a C/O ratio of 14.8) that are tens of micrometers large. Successful functionalization of graphene was confirmed by the appearance of phosphorus and iron peaks in the X-ray photoelectron spectrum. Further, high-performance polylactic acid/f-GNS nanocomposites are readily fabricated by a convenient masterbatch strategy. Notably, inclusion of well-dispersed f-GNS resulted in dramatic suppression on fire hazards of polylactic acid in terms of reduced peak heat-release rate (decreased by 40%), low CO yield, and formation of a high graphitized protective char layer. Moreover, obviously improvements in crystallization rate and thermal conductivities of polylactic acid nanocomposites were observed, highlighting its promising potential in practical application. This novel strategy toward the simultaneous exfoliation and functionalization for graphene demonstrates a simple yet very effective approach for fabricating graphene-based flame retardants.

  20. A comparative investigation on adsorption performances of mesoporous activated carbon prepared from waste rubber tire and activated carbon for a hazardous azo dye--Acid Blue 113.

    Science.gov (United States)

    Gupta, V K; Gupta, Bina; Rastogi, Arshi; Agarwal, Shilpi; Nayak, Arunima

    2011-02-15

    A mesoporous carbon developed from waste tire rubber, characterized by chemical analysis, FTIR, and SEM studies, was used as an adsorbent for the removal and recovery of a hazardous azo dye, Acid Blue 113. Surface area, porosity, and density were determined. The adsorption of the dye over the prepared adsorbent and a commercial activated carbon was achieved under different pH, adsorbate concentration, sieve size, adsorbent dosage, contact time and temperature conditions. Langmuir and Freundlich adsorption isotherm models were applied and thermodynamic parameters were calculated. Kinetic studies indicated that the adsorption process follow first order kinetics and particle diffusion mechanisms are operative. By percolating the dye solution through fixed-bed columns the bulk removal of the Acid Blue 113 was carried out and necessary parameters were determined to find out the percentage saturation of both the columns. Recovery of the dye was made by eluting 0.1 M NaOH through the column.

  1. [Determination of nine hazardous elements in textiles by inductively coupled plasma optical emission spectrometer after microwave-assisted dilute nitric acid extraction].

    Science.gov (United States)

    Chen, Fei; Xu, Dian-dou; Tang, Xiao-ping; Cao, Jing; Liu, Ya-ting; Deng, Jian

    2012-01-01

    Textiles are easily contaminated by heavy metals in the course of processing. In order to monitor the quality of textiles, a new method was developed for simultaneous determination of arsenic, antimony, lead, cadmium, chromium, cobalt, copper, nickel and mercury in textiles by inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave-assisted dilute nitric acid extraction. After optimizing extraction conditions, we ultimately selected 5% nitric acid as extractant and 5 min as extraction time with the extraction temperature of 120 degrees C and instrument power of 400W in the microwave-assisted extraction procedure. Nine hazardous elements were detected sequentially by ICP-OES. The results showed that the detection limits were 0.3-15 microg x L(-1) and the recoveries 73.6%-105% with the RSDs (n = 3) of 0.1%-3%. The proposed method was successfully used to determine nine elements in cotton, wool, terylene and acrylic.

  2. Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids.

    Science.gov (United States)

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

    2016-08-16

    Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes.

  3. Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids

    Science.gov (United States)

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

    2016-08-01

    Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes.

  4. Quality assurance of commercial beeswax II. Gas chromatography-electron impact ionization mass spectrometry of alcohols and acids.

    Science.gov (United States)

    Jiménez, J J; Bernal, J L; Aumente, S; Toribio, L; Bernal, J

    2003-07-25

    Gas chromatography with mass spectrometric detection was used to find the fraction of alcohols and acids present in pure beeswax from Apis mellifera. Some new compounds not described till now were found, such as a family of unsaturated linear fatty acids, several hydroxyacids and 1,2,3-propanetriol monoesters. The chromatographic profiles obtained from pure beeswax and bee-rejected foundation beeswax can be used to discriminate them; they mainly differ in the amount of some acids and alcohols.

  5. Acetylsalicylic acid as a potential pediatric health hazard: legislative aspects concerning accidental intoxications in the European Union.

    Science.gov (United States)

    Mund, Menen E; Gyo, Christoph; Brüggmann, Dörthe; Quarcoo, David; Groneberg, David A

    2016-01-01

    Acetylsalicylic acid is a frequently used medication worldwide. It is not used in pediatrics due its association with Reye syndrome. However, in case of pediatric intoxication, children are more fragile to salicylate poisoning because of their reduced ability of buffer the acid stress. Intoxication leads to a decoupling of oxidative phosphorylation and subsequently to a loss in mitochondrial function. Symptoms of poisoning are diverse; eventually they can lead to the death of the patient. Governmental websites of various EU countries were searched for legal information on acetylsalicylic acid availability in pharmacies and non-pharmacy stores. Various EU countries permit prescription-free sales of acetylsalicylic acid in pharmacies and non-pharmacy stores. In Sweden acetylsalicylic acid 500 mg may be sold in a maximum package size of 20 tablets or effervescent tablets in a non-pharmacy. In the UK a maximum of 16 tablets of acetylsalicylic acid 325 mg is allowed to sell in non-pharmacies. In Ireland acetylsalicylic acid is classified as S2 medication. Subsequently, acetylsalicylic acid is allowed to be sold prescription-free in pharmacies and non-pharmacy stores. In the Netherlands acetylsalicylic acid may only be sold in drug stores or pharmacies. A maximum of 24 tablets of 500 mg is allowed to purchase in a drug store. Several countries in the European Union are permitted to offer acetylsalicylic acid prescription-free in pharmacies and non-pharmacy stores without legal guidance on the storage position within the store. Further research is needed to investigate whether acetylsalicylic acid is located directly accessible to young children within the stores in EU countries which permit prescription-free sales of acetylsalicylic acid.

  6. Ab initio studies of aspartic acid conformers in gas phase and in solution

    Science.gov (United States)

    Chen, Mingliang; Lin, Zijing

    2007-10-01

    Systematic and extensive conformational searches of aspartic acid in gas phase and in solution have been performed. For the gaseous aspartic acid, a total of 1296 trial canonical structures and 216 trial zwitterionic structures were generated by allowing for all combinations of internal single-bond rotamers. All the trial structures were optimized at the B3LYP /6-311G* level and then subjected to further optimization at the B3LYP /6-311++G** level. A total of 139 canonical conformers were found, but no stable zwitterionic structure was found. The rotational constants, dipole moments, zero-point vibrational energies, harmonic frequencies, and vertical ionization energies of the canonical conformers were determined. Single-point energies were also calculated at the MP2/6-311++G** and CCSD /6-311++G** levels. The equilibrium distributions of the gaseous conformers at various temperatures were calculated. The proton affinity and gas phase basicity were calculated and the results are in excellent agreement with the experiments. The conformations in the solution were studied with different solvation models. The 216 trial zwitterionic structures were first optimized at the B3LYP /6-311G* level using the Onsager self-consistent reaction field model (SCRF) and then optimized at the B3LYP /6-311++G** level using the conductorlike polarized continuum model (CPCM) SCRF theory. A total of 22 zwitterions conformers were found. The gaseous canonical conformers were combined with the CPCM model and optimized at the B3LYP /6-311++G** level. The solvated zwitterionic and canonical structures were further examined by the discrete/SCRF model with one and two water molecules. The incremental solvation of the canonical and zwitterionic structures with up to six water molecules in gas phase was systematically examined. The studies show that combining aspartic acid with at least six water molecules in the gas phase or two water molecules and a SCRF solution model is required to provide

  7. The partitioning of Nitric Acid between the gas phase and condensed phase of aqueous sulfate aerosols.

    Science.gov (United States)

    Mentel, T. F.; Folkers, M.; Sebald, H.; Wahner, A.

    2001-12-01

    The heterogeneous hydrolysis of N2O_5 on aqueous aerosol surfaces is an important source of atmospheric HNO3. We generated HNO3 by heterogeneous hydrolysis of N2O_5 on aqueous ammonium and sodium sulfate aerosols and studied its partitioning between the gas phase and the aerosol phase. The experiments were performed in the large aerosol chamber at the FZ-Jülich at several relative humidities. Gas phase processes and the composition of the aerosols were monitored on-line simultaneously by FTIR spectroscopy and by Steam Jet Aerosol Collection/Ion Chromatography. The aerosol size distributions in the range of 20 nm to 5 μ m were measured by differential electromobility classification and by aerodynamic particle sizing. In the presence of aqueous bisulfate and sulfate aerosols a fast heterogeneous formation HNO3 is observed. (The reaction probability of N2O_5 is about 0.02.) In the case of the acidic bisulfate aerosols the major fraction of heterogeneously formed HNO3 resides in the gas phase. For neutral sulfate aerosols a significant fraction of HNO3 is taken up by the condensed phase of the aerosols. This leads to a distinctive growth of the aerosol population during the heterogeneous hydrolysis of N2O_5, which is observable in the number size distribution as well as in IR extinction measurements. The observed partitioning of HNO3 between gas phase and aqueous aerosol phase can be quantitatively understood by a Pitzer based thermodynamic model for salt solutions of high ionic strength. The model calculations and low resolution FTIR spectroscopy demonstrate that protonation of sulfate to bisulfate is the driving force for the uptake of HNO3 in neutral sulfate aerosols.

  8. Transportation of hazardous goods

    CERN Multimedia

    TS Department

    2008-01-01

    A general reminder: any transportation of hazardous goods by road is subject to the European ADR rules. The goods concerned are essentially the following: Explosive substances and objects; Gases (including aerosols and non-flammable gases such as helium and nitrogen); Flammable substances and liquids (inks, paints, resins, petroleum products, alcohols, acetone, thinners); Toxic substances (acids, thinners); Radioactive substances; Corrosive substances (paints, acids, caustic products, disinfectants, electrical batteries). Any requests for the transport of hazardous goods must be executed in compliance with the instructions given at this URL: http://ts-dep.web.cern.ch/ts-dep/groups/he/HH/adr.pdf Heavy Handling Section TS-HE-HH 73793 - 160364

  9. Investigation of the gas-phase hydrogen/deuterium exchange behavior of aromatic dicarboxylic acids in a quadrupole ion trap

    Science.gov (United States)

    Chipuk, Joseph E.; Brodbelt, Jennifer S.

    2007-11-01

    Gas-phase hydrogen/deuterium (H/D) exchange reactions of four deprotonated aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid and 2,6-naphthalic acid) with D2O were performed in a quadrupole ion trap mass spectrometer. Experimental results showed significant differences in the rate and extent of exchange when the relative position of the carboxylic acid groups varied. Spontaneous and near complete exchange of one aromatic hydrogen atom occurred when the carboxylic acid groups were in the meta-position, whereas no additional exchange was observed for either the ortho- or para-isomers or for the structurally similar naphthalic acid. Computational investigations support the participation of several possible exchange mechanisms with the contribution of each relying heavily on the relative orientation of the acid moieties. A relay mechanism that bridges the deprotonation site and the labile hydrogen site appears to be responsible for the H/D exchange of not only the labile hydrogen atom of isophthalic acid, but also for the formation of a stable carbanion and corresponding subsequent exchange of one aromatic hydrogen atom. The impact of hydrogen bonding on the relay mechanism is demonstrated by the reaction of phthalic acid as the extent and rate of reaction are greatly retarded by the favorable interaction of the two carboxylic acid groups. Finally, a flip-flop mechanism is likely responsible for the exchange of both terephthalic acid and 2,6-naphthalic acid where the reactive sites are too remote for exchange via relay.

  10. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

    Directory of Open Access Journals (Sweden)

    Jafari Mohammad Javad

    2012-12-01

    Full Text Available Abstract The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p 3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream.

  11. Chemical ionization mass spectrometry (CIMS may not measure all gas-phase sulfuric acid if base molecules are present

    Directory of Open Access Journals (Sweden)

    T. Kurtén

    2010-12-01

    Full Text Available The state-of-the art method for measuring atmospheric gas-phase sulfuric acid is chemical ionization mass spectrometry (CIMS based on nitrate reagent ions. Using computed proton affinities and reaction thermodynamics for the relevant charging reactions, we show that in the presence of strong bases such as amines, which tend to cluster with the sulfuric acid molecules, a significant fraction of the total gas-phase sulfuric acid may not be measured by a CIMS instrument. If this is the case, this effect has to be taken into account in the interpretation of atmospheric sulfuric acid measurement data, as well as in intercomparison of different CIMS instruments, which likely have different susceptibilities to amine-sulfuric acid clustering.

  12. The effect of zeolite treatment by acids on sodium adsorption ratio of coal seam gas water.

    Science.gov (United States)

    Wang, Xiaoyu; Ozdemir, Orhan; Hampton, Marc A; Nguyen, Anh V; Do, Duong D

    2012-10-15

    Many coal seam gas (CSG) waters contain a sodium ion concentration which is too high relative to calcium and magnesium ions for environment acceptance. Natural zeolites can be used as a cheap and effective method to control sodium adsorption ratio (SAR, which is a measure of the relative preponderance of sodium to calcium and magnesium) due to its high cation exchange capacity. In this study, a natural zeolite from Queensland was examined for its potential to treat CSG water to remove sodium ions to lower SAR and reduce the pH value. The results demonstrate that acid activated zeolite at 30%wt solid ratio can reduce the sodium content from 563.0 to 182.7 ppm; the pH from 8.74 to 6.95; and SAR from 70.3 to 18.5. Based on the results of the batch experiments, the sodium adsorption capacity of the acid-treated zeolite is three times greater than that of the untreated zeolite. Both the untreated and acid-treated zeolite samples were characterized using zeta potential, surface characterization, DTA/TG and particle size distribution in order to explain their adsorption behaviours.

  13. 危险废物焚烧工程烟气治理工艺设计%Process Design on the Treatment of Flue Gas from Hazardous Waste Incineration

    Institute of Scientific and Technical Information of China (English)

    岳强; 范亚民; 耿磊; 郑晖; 王金龙

    2012-01-01

    Based on the characteristics of flue gas from hazardous waste rotary kiln, the process of waste heat boiler, quench tower, activated carbon adsorption, bag-type dust collector, wet deacidification was put forward. It can effectively inhibit the resynthesis of dioxins. And the flue gas can reach the standard of Pollution Control Standard for Hazardous Wastes Incineration (GB 18484—2001) after treatment.%根据危险废物回转窑焚烧烟气的特点,提出采用余热锅炉、急冷塔、活性炭吸附、布袋除尘、湿法脱酸的烟气治理工艺,可有效抑制二恶英的再合成,排放的烟气能够达到GB 18484-2001危险废物焚烧污染控制标准的要求.

  14. Recent Selected Ion Flow Tube (SIFT) Studies Concerning the Formation of Amino Acids in the Gas Phase

    Science.gov (United States)

    Jackson, Douglas M.; Adams, Nigel G.; Babcock, Lucia M.

    2006-01-01

    Recently the simplest amino acid, glycine, has been detected in interstellar clouds, ISC, although this has since been contested. In order to substantiate either of these claims, plausible routes to amino acids need to be investigated. For gas phase synthesis, the SIFT technique has been employed to study simple amino acids via ion-molecule reactions of several ions of interstellar interest with methylamine, ethylamine, formic acid, acetic acid, and methyl formate. Carboxylic acid type ions were considered in the reactions involving the amines. In reactions where the carboxylic acid and methyl formate neutrals were studied, the reactant ions were primarily amine ion fragments. It was observed that the amines and acids preferentially fragment or accept a proton whenever energetically possible. NH3(+), however, uniquely reacted with the neutrals via atom abstraction to form NH4(+). These studies yielded a body of data relevant to astrochemistry, supplementing the available literature. However, the search for gas phase routes to amino acids using conventional molecules has been frustrated. Our most recent research investigates the fragmentation patterns of several amino acids and several possible routes have been suggested for future study.

  15. Application of acetate derivatives for gas chromatography-mass spectrometry: novel approaches on carbohydrates, lipids and amino acids analysis.

    Science.gov (United States)

    Sassaki, Guilherme L; Souza, Lauro M; Serrato, Rodrigo V; Cipriani, Thales R; Gorin, Philip A J; Iacomini, Marcello

    2008-10-24

    The structure of glycoconjugates has been determined by several chromatographic methods, however gas chromatography-mass spectrometry (GC-MS) has been widely used to identify and quantify the volatile trimethylsilyl and fluoroacyl derivatives. Adapting the reduction/acetylation strategies, we had performed the derivatization of all monosaccharide class, as well as amino acids and OH-fatty acids as from different glycoconjugates. Uronic acids gave characteristic ions at m/z 143, 156 and 173, and 19 amino acids derivatives, gave molecular ions [M]+ and daughter ions of [M-59]+ and [M-43]+ on electron impact (EI)-MS, which provide their rapid identification.

  16. Detection of a CO and NH3 gas mixture using carboxylic acid-functionalized single-walled carbon nanotubes.

    Science.gov (United States)

    Dong, Ki-Young; Choi, Jinnil; Lee, Yang Doo; Kang, Byung Hyun; Yu, Youn-Yeol; Choi, Hyang Hee; Ju, Byeong-Kwon

    2013-01-01

    Carbon nanotubes (CNT) are extremely sensitive to environmental gases. However, detection of mixture gas is still a challenge. Here, we report that 10 ppm of carbon monoxide (CO) and ammonia (NH3) can be electrically detected using a carboxylic acid-functionalized single-walled carbon nanotubes (C-SWCNT). CO and NH3 gases were mixed carefully with the same concentrations of 10 ppm. Our sensor showed faster response to the CO gas than the NH3 gas. The sensing properties and effect of carboxylic acid group were demonstrated, and C-SWCNT sensors with good repeatability and fast responses over a range of concentrations may be used as a simple and effective detection method of CO and NH3 mixture gas.

  17. Study on the removal of NOx from simulated flue gas using acidic NaClO2 solution

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The study on the removal of NOx from simulated flue gas has been carried out in lab-scale bubbling reactor using acidic solutions of sodium chlorite. Experiments were performed at various pH values and inlet NO concentrations in absence as well as presence of SO2 gas at 45oC. The effect of SO2 on NO oxidation and NO2 absorption was critically examined. The oxidative ability of sodium chlorite was investigated at different pH values and it was found to be a better oxidant at a pH less than 4. In acidic medium, sodium chlorite decomposed into ClO2 gas, which is believed to participate in NO oxidation as well as in NO2 absorption. A plausible NOx removal mechanism using acidic sodium chlorite solution has been postulated. A maximum NOx removal efficiency of about 81% has been achieved.

  18. Positive synergistic effect of the reuse and the treatment of hazardous waste on pyrometallurgical process of lead recovery from waste lead-acid batteries

    Directory of Open Access Journals (Sweden)

    Marija Štulović

    2014-09-01

    Full Text Available Modification and optimization of the pyrometallurgical process of lead recovering from the waste lead-acid batteries have been studied in this paper. The aim of this research is to develop a cleaner production in the field of the secondary lead metallurgy. Lead smelting process with the addition of flux (sodium(I-carbonate and reducing agents (coke, iron has been followed. The modified smelting process with the addition of hazardous waste (activated carbon as alternative reducing agents has shown positive results on the quality of the secondary lead, the generated slag and the process gases. Filtration efficiency of the gases, the return of baghouse dust to the process and use of oxygen burners have positive effect on the environment protection and energy efficiency. Optimization of the recycling process has been based on the properties of the slag. Stabilization of slag is proposed in the furnace with addition of waste dust from the recycling of cathode ray tube (CRT monitors. Phosphorus compounds from dust reduce leachability of toxic elements from the generated slag. Reduction the slag amount and its hazardous character through the elimination of migratory heavy metals and valorization of useful components have been proposed in the patented innovative device - cylindrical rotating washer/separator.

  19. 危险废物焚烧烟气中二噁英控制策略探讨%The control strategy discussion on the PCDD/Fs in hazardous waste incineration flue gas

    Institute of Scientific and Technical Information of China (English)

    刘凯; 覃楠钧; 施耀华; 宋晓薇

    2015-01-01

    For the problem of hazardous waste incineration is bound to produce PCDD/Fs, according to the mechanism and influencing factors of PCDD/Fs generation, this study discusses how the composition of burning material and flue-gas temperature and quantity of activated carbon ejecting affect the emission of PCDD/Fs. Combining with the analysis results, proposing the hazardous waste should be classified collection, and discussing the control requirements and conditions of flue-gas temperature and quantity of activated carbon ejecting, offering the control strategy on the PCDD/Fs in hazardous waste incineration flue gas in actually engineering project.%针对我国危险废物焚烧必然产生二噁英的问题,根据二噁英生成的机理和影响因素,探讨焚烧物料组成、烟气温度、活性炭喷射量等因素对二噁英排放的影响。结合分析探讨结果,提出在危险废物应进行分类收集,并讨论了烟气温度、活性炭喷射量的控制要求和条件,提供了实际工程应用中危险废物焚烧烟气中二噁英的控制策略。

  20. [Determination of phthalic acid esters in textiles by solid phase extraction-gas chromatography].

    Science.gov (United States)

    Niu, Zengyuan; Ye, Xiwen; Fang, Liping; Xue, Qiuhong; Sun, Zhongsong

    2006-09-01

    A method was established for the simultaneous determination of some phthalic acid esters, namely, dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPrP), dibutyl phthalate (DBP), diamyl phthalate (DAP), dihexyl phthalate (DHP), benzyln-butyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP), dicyclohexyl phthalate (DCHP), di-n-octyl phthalate (DNOP), diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP) in textiles by solid phase extraction (SPE) coupled with gas chromatography (GC). The phthalic acid esters in textiles were extracted by Soxhlet extraction with hexane, the extracts were then cleaned up and enriched by a strong anion exchange (SAX) SPE cartridge. The parameters affecting the purification efficiency of SPE cartridge, such as solvent conditioning, rinsing, and elution, were studied. Conditioning with 5 mL hexane and rinsing with 3 mL isooctane were proved to be the optimal conditions. Of the several solvent ratios (ethylacetate in hexane) used for selective elution of phthalic acid esters from the SAX SPE cartridge, the 15% (v/v) content for ethylacetate in hexane gave the best result. Under the optimized conditions, the recoveries of phthalic acid esters for spiked standards (n=7) were 86.3%-102.7%, and the relative standard deviations (RSDs) were less than 5%. In this method the detection limits for DMP, DEP, DPrP, DBP, DAP, BBP, DCHP, DEHP, DNOP were all below 1 mg/kg, and the detection limits for DINP and DIDP were 1.74 mg/kg and 1.55 mg/kg respectively. This SPE-GC method is sensitive, accurate and suitable for the analysis of phthalate environmental hormones in textiles.

  1. Gas-phase hydration thermochemistry of sodiated and potassiated nucleic acid bases.

    Science.gov (United States)

    Wincel, Henryk

    2012-09-01

    Hydration reactions of sodiated and potassiated nucleic acid bases (uracil, thymine, cytosine, and adenine) produced by electrospray have been studied in a gas phase using the pulsed ion-beam high-pressure mass spectrometer. The thermochemical properties, ΔH(o)(n), ΔS(o)(n), and ΔG(o)(n), for the hydrated systems were obtained from hydration equilibrium measurement. The structural aspects of the hydrated complexes are discussed in conjunction with available literature data. The correlation between water binding energies in the hydrated complexes and the corresponding metal ion affinities of nucleobases suggests that a significant (if not dominant) amount of the canonical structure of cytosine undergoes tautomerization during electrospray ionization, and the thermochemical values for cationized cytosine probably correspond to a mixture of tautomeric complexes.

  2. Infrared and density functional theory studies of formic acid hydrate clusters in noble gas matrices

    Science.gov (United States)

    Ito, Fumiyuki

    2016-08-01

    Infrared absorption spectra of formic acid hydrate clusters (HCOOH)m(H2O)n have been measured in noble gas matrices (Ar and Kr). The concentration dependence of the spectra and the comparison with a previous experimental study on HCOOH(H2O) and HCOOH(H2O)2 [Geoge et al., Spectrochim. Acta, Part A 60 (2004) 3225] led to the identification of large clusters. Density functional theory calculations at the B3LYP-DCP/6-31+G(2d,2p) level were carried out to determine the anharmonic vibrational properties of the clusters, enabling a consistent assignment of the observed vibrational peaks to specific clusters.

  3. Advanced Acid Gas Separation Technology for Clean Power and Syngas Applications

    Energy Technology Data Exchange (ETDEWEB)

    Amy, Fabrice [Air Products and Chemicals Inc., Allentown, PA (United States); Hufton, Jeffrey [Air Products and Chemicals Inc., Allentown, PA (United States); Bhadra, Shubhra [Air Products and Chemicals Inc., Allentown, PA (United States); Weist, Edward [Air Products and Chemicals Inc., Allentown, PA (United States); Lau, Garret [Air Products and Chemicals Inc., Allentown, PA (United States); Jonas, Gordon [Air Products and Chemicals Inc., Allentown, PA (United States)

    2015-06-30

    Air Products has developed an acid gas removal technology based on adsorption (Sour PSA) that favorably compares with incumbent AGR technologies. During this DOE-sponsored study, Air Products has been able to increase the Sour PSA technology readiness level by successfully operating a two-bed test system on coal-derived sour syngas at the NCCC, validating the lifetime and performance of the adsorbent material. Both proprietary simulation and data obtained during the testing at NCCC were used to further refine the estimate of the performance of the Sour PSA technology when expanded to a commercial scale. In-house experiments on sweet syngas combined with simulation work allowed Air Products to develop new PSA cycles that allowed for further reduction in capital expenditure. Finally our techno economic analysis of the use the Sour PSA technology for both IGCC and coal-to-methanol applications suggests significant improvement of the unit cost of electricity and methanol compared to incumbent AGR technologies.

  4. Analysis of Gas Permeability Characteristics of Poly(Lactic Acid/Poly(Butylene Succinate Nanocomposites

    Directory of Open Access Journals (Sweden)

    Amita Bhatia

    2012-01-01

    Full Text Available Gas permeability and morphological properties of nanocomposites prepared by the mixing of poly(lactic acid (PLA, poly(butylene succinate (PBS, and clay was investigated. While the composition of PLA and PBS polymers was fixed as 80% and 20% by weight, respectively, for all the nanocomposites, clay contents varied from 1 to 10 wt%. From the morphological studies using both wide angle X-ray diffraction and transmission electron microscopy, the nanocomposite having 1 wt% of clay was considered to have a mixed morphology of intercalated and delaminated structure, while some clusters or agglomerated particles were detected for nanocomposites having 3 and more than 3 wt% of clay content. However, the average particle size of the dispersed PBS phase was reduced significantly from 7 μm to 30–40 nm with the addition of clay in the blend. The oxygen barrier property was improved significantly as compared to the water vapor. A model based on gas barrier property was used for the validation of the oxygen relative permeabilities of PLA/PBS/clay nanocomposites. PLA/PBS/clay nanocomposites validated the Bharadwaj model up to 3 wt% of clay contents only, while for nanocomposites of higher clay contents the Bharadwaj model was invalid due to the clusters and agglomerates formed.

  5. Fundamental studies of acid gas treating by aqueous alkanolamines: Vapor-liquid equilibrium studies. Annual report, January-December 1992

    Energy Technology Data Exchange (ETDEWEB)

    Ng, H.J.; Huang, S.H.

    1993-02-01

    The project addresses the measurement of the solubilities of acid gases such as H2S and CO2 in alkanolamine solutions. Systems of acid gas mixtures and of amine mixtures are included in the study. The temperature range extended from 40 to 120 C and the partial pressure of the acid gases ranged from 0.005 kPa up to 3,000 kPa. The range is sufficient to cover most of the industrial operating conditions for amine-based sweeteners. The planned schedule of experimental work was maintained during 1992. The solubilities of H2S in seven amine systems have been measured and reported. The study will be continued in 1993. The measurements will be extended to systems containing CO2 as the acid gas.

  6. Strontium isotope quantification of siderite, brine and acid mine drainage contributions to abandoned gas well discharges in the Appalachian Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Elizabeth C. [Univ. of Pittsburgh, PA (United States). Dept. of Geology and Planetary Science; Capo, Rosemary C. [Univ. of Pittsburgh, PA (United States). Dept. of Geology and Planetary Science; Stewart, Brian W. [Univ. of Pittsburgh, PA (United States). Dept. of Geology and Planetary Science; Hedin, Robert S. [Hedin Environmental, Pittsburgh, PA (United States); Weaver, Theodore J. [Hedin Environmental, Pittsburgh, PA (United States); Edenborn, Harry M. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2013-04-01

    Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotope mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs.

  7. Formation of Amino Acids on the Sonolysis of Aqueous Solutions Containing Acetic Acid, Methane, or Carbon Dioxide, in the Presence of Nitrogen Gas.

    Science.gov (United States)

    Dharmarathne, Leena; Grieser, Franz

    2016-01-21

    The sonolysis of aqueous solutions containing acetic acid, methane, or carbon dioxide in the presence of nitrogen gas was found to produce a number of different amino acids at a rate of ∼1 to 100 nM/min, using ultrasound at an operating power of 70 W and 355 kHz. Gas-phase elementary reactions are suggested, and discussed, to account for the formation of the complex biomolecules from the low molar mass solutes used. On the basis of the results, a new hypothesis is presented to explain the formation of amino acids under primitive atmospheric conditions and how their formation may be linked to the eventual abiotic genesis of life on Earth.

  8. Determination of methacrylic acid in food simulants by pyrolytic butylation-gas chromatography.

    Science.gov (United States)

    Huang, Zhongping; Qiu, Ruofeng; Liu, Tingfei; Huang, Yilei; Zhu, Zuoyi; Wang, Lili

    2016-07-08

    An on-line pyrolytic butylation approach was proposed to determine methacrylic acid (MA) in food simulants by gas chromatography (GC) without an expensive pyrolyzer. MA in food simulants was converted into butyl methacrylate in the presence of tetrabutylammonium hydroxide (TBAH) without any pretreatment at 330°C in the injection-port, contributing to high GC signal response. The derivatizing conditions for the proposed method were optimized, namely the injection-port temperature, type and amount of the organic alkaline used for derivatization. A series of standard solutions of MA in the range of 1.0-50mg/kg were analyzed with correlation coefficient r≥0.9975. The limits of detection (LODs) were less than 0.15mg/kg for MA in four matrix simulants (distilled water, 3%w/v acetic acid, 10%v/v ethanol, and isooctane). Relative standard deviations (RSDs) for retention time, peak height and peak area were all less than 3.88%. The technique was successfully applied to the analysis of MA migrating from plastic cup samples, with recoveries of added MA in the range of 96.5-123.0%. Direct injection of the simulants into the GC system after migration tests, without any pretreatment step, makes the developed method of great value for rapid screening analysis of samples in bulks.

  9. Rapid and simple clean-up and derivatizaton procedure for the gas chromatographic determination of acidic drugs in plasma

    NARCIS (Netherlands)

    Roseboom, H.; Hulshoff, A.

    1979-01-01

    A rapid and simple clean-up and derivatization procedure that can be generally applied to the gas chromatographie (GC) determination of acidic drugs of various chemical and therapeutic classes is described. The drugs are extracted from acidified plasma with chloroform containing 5% of isopropanol, w

  10. Determination of urinary 18 beta-glycyrrhetinic acid by gas chromatography and its clinical application in man

    NARCIS (Netherlands)

    Guillaume, CPF; van der Molen, JC; Kerstens, MN; Dullaart, RPF; Wolthers, BG

    1999-01-01

    A sensitive and quantitative gas chromatographic assay for the determination of 18 beta-glycyrrhetinic acid (18 beta-GA), the main metabolite of glycyrrhizin after oral licorice consumption in human urine, has been developed and validated. For the extraction of 18 beta-GA from urine two Sep-Pak C-18

  11. PREPARATION OF ASYMMETRIC POLYETHERKETONE FLAT AND HOLLOW FIBER MEMBRANES FOR GAS SEPARATION USING ACETIC ACID BASED COAGULANTS

    Institute of Scientific and Technical Information of China (English)

    Ji-ping Yang; Philip J. Brown

    2008-01-01

    Membranes for gas separation have developed significantly in the last twenty years, however, there is still a need for high temperature and chemically resistant membranes that exhibit good selectivity and gas permeability. Our study examines the fundamental properties of polyetherketone (PEK, a thermally stable and chemically resistant polymer)membranes prepared using concentrated sulphuric acid (98% H2SO4) as the solvent. Non-solvents used in the work included acetic acid, ethanol, methanol, glycerol, and water. The concentration of the polymer solutions was chosen to be 20%. The membrane structures were examined using SEM, and the gas separation properties were measured using a lab-scale test rig.The results show that formation and control of membrane structures are complicated, and many preparation parameters affect membrane morphology and performance. Using appropriate conditions skinned sponge-like structured hollow fiber membranes could be made from PEK by using acetic acid as the internal coagulant. PEK hollow fibers spun from 20%PEK/H2SO4 solutions with 50% aqueous acetic acid as internal coagulant had selectivity for hydrogen/methane of around 40, implying a solution diffusion separation mechanism for gas separation without the need for fiber coating or after post-treatments.

  12. Electrophilic acid gas-reactive fluid, proppant, and process for enhanced fracturing and recovery of energy producing materials

    Science.gov (United States)

    Fernandez, Carlos A.; Heldebrant, David J.; Bonneville, Alain H. R.; Jung, Hun Bok; Carroll, Kenneth

    2016-09-20

    An electrophilic acid gas-reactive fracturing and recovery fluid, proppant, and process are detailed. The fluid expands in volume to provide rapid and controlled increases in pressure that enhances fracturing in subterranean bedrock for recovery of energy-producing materials. Proppants stabilize openings in fractures and fissures following fracturing.

  13. Direct analysis of intact glycidyl fatty acid esters in edible oils using gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    van Steenbergen, H.; Hrnčiřík, K.; Ermacora, A.; de Koning, S.; Janssen, H.-G.

    2013-01-01

    Glycidyl esters (GE), fatty acid esters of glycidol, are process contaminants formed during edible oil processing. A novel direct method for the determination of intact GE in oils and fats based on gas chromatography-mass spectrometry (GC-MS) is presented. The method consists of a simple extraction

  14. A comparative investigation on adsorption performances of mesoporous activated carbon prepared from waste rubber tire and activated carbon for a hazardous azo dye-Acid Blue 113

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, V.K., E-mail: vinodfcy@iitr.ernet.in [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Gupta, Bina [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Rastogi, Arshi [Chemistry Department, K.L.D.A.V.(P.G.) College, Roorkee (India); Agarwal, Shilpi [School of Studies in Chemistry, Jiwaji University, Gwalior, MP (India); Nayak, Arunima [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2011-02-15

    Research highlights: {yields} The system is cheap, efficient and fast for the removal of dyes from waters. {yields} Higher adsorption capacity is due to higher mesoporous volume of the adsorbent. {yields} The rate determining step of the adsorption process is particle diffusion. - Abstract: A mesoporous carbon developed from waste tire rubber, characterized by chemical analysis, FTIR, and SEM studies, was used as an adsorbent for the removal and recovery of a hazardous azo dye, Acid Blue 113. Surface area, porosity, and density were determined. The adsorption of the dye over the prepared adsorbent and a commercial activated carbon was achieved under different pH, adsorbate concentration, sieve size, adsorbent dosage, contact time and temperature conditions. Langmuir and Freundlich adsorption isotherm models were applied and thermodynamic parameters were calculated. Kinetic studies indicated that the adsorption process follow first order kinetics and particle diffusion mechanisms are operative. By percolating the dye solution through fixed-bed columns the bulk removal of the Acid Blue 113 was carried out and necessary parameters were determined to find out the percentage saturation of both the columns. Recovery of the dye was made by eluting 0.1 M NaOH through the column.

  15. Acid decomposition and thiourea leaching of silver from hazardous jarosite residues: Effect of some cations on the stability of the thiourea system.

    Science.gov (United States)

    Calla-Choque, D; Nava-Alonso, F; Fuentes-Aceituno, J C

    2016-11-05

    The recovery of silver from hazardous jarosite residues was studied employing thiourea as leaching agent at acid pH and 90°C. The stability of the thiourea in synthetic solutions was evaluated in the presence of some cations that can be present in this leaching system: cupric and ferric ions as oxidant species, and zinc, lead and iron as divalent ions. Two silver leaching methods were studied: the simultaneous jarosite decomposition-silver leaching, and the jarosite decomposition followed by the silver leaching. The study with synthetic solutions demonstrated that cupric and ferric ions have a negative effect on thiourea stability due to their oxidant properties. The effect of cupric ions is more significant than the effect of ferric ions; other studied cations (Fe(2+), Zn(2+), Pb(2+)) had no effect on the stability of thiourea. When the decomposition of jarosite and the silver leaching are carried out simultaneously, 70% of the silver can be recovered. When the acid decomposition was performed at pH 0.5 followed by the leaching step at pH 1, total silver recovery increased up to 90%. The zinc is completely dissolved with any of these processes while the lead is practically insoluble with these systems producing a lead-rich residue.

  16. Critical Test of Some Computational Chemistry Methods for Prediction of Gas-Phase Acidities and Basicities.

    Science.gov (United States)

    Toomsalu, Eve; Koppel, Ilmar A; Burk, Peeter

    2013-09-10

    Gas-phase acidities and basicities were calculated for 64 neutral bases (covering the scale from 139.9 kcal/mol to 251.9 kcal/mol) and 53 neutral acids (covering the scale from 299.5 kcal/mol to 411.7 kcal/mol). The following methods were used: AM1, PM3, PM6, PDDG, G2, G2MP2, G3, G3MP2, G4, G4MP2, CBS-QB3, B1B95, B2PLYP, B2PLYPD, B3LYP, B3PW91, B97D, B98, BLYP, BMK, BP86, CAM-B3LYP, HSEh1PBE, M06, M062X, M06HF, M06L, mPW2PLYP, mPW2PLYPD, O3LYP, OLYP, PBE1PBE, PBEPBE, tHCTHhyb, TPSSh, VSXC, X3LYP. The addition of the Grimmes empirical dispersion correction (D) to B2PLYP and mPW2PLYP was evaluated, and it was found that adding this correction gave more-accurate results when considering acidities. Calculations with B3LYP, B97D, BLYP, B2PLYPD, and PBE1PBE methods were carried out with five basis sets (6-311G**, 6-311+G**, TZVP, cc-pVTZ, and aug-cc-pVTZ) to evaluate the effect of basis sets on the accuracy of calculations. It was found that the best basis sets when considering accuracy of results and needed time were 6-311+G** and TZVP. Among semiempirical methods AM1 had the best ability to reproduce experimental acidities and basicities (the mean absolute error (mae) was 7.3 kcal/mol). Among DFT methods the best method considering accuracy, robustness, and computation time was PBE1PBE/6-311+G** (mae = 2.7 kcal/mol). Four Gaussian-type methods (G2, G2MP2, G4, and G4MP2) gave similar results to each other (mae = 2.3 kcal/mol). Gaussian-type methods are quite accurate, but their downside is the relatively long computational time.

  17. Current electrosurgical practice: hazards.

    Science.gov (United States)

    Pearce, J

    1985-01-01

    The beneficial aspects of electrosurgical cutting and coagulating techniques are nearly too numerous to list. The major contribution and electrosurgery has been to drastically reduce both blood loss and operative time resulting in reduced morbidity and mortality. There are, as well, procedures which would not be possible without electrosurgery. Nonetheless, as a source of high energy in the operating theatre, there are hazards attendant to the use of electrosurgery. Moreover, since high frequency signals are involved, the nature of the machine-patient interactions creating a potentially hazardous situation many not be easily identifiable. The significant hazards of electrosurgery in use are: explosions of combustible mixtures including anaesthesia gas and bowel gas; interference with instruments and pacemakers; stimulation of excitable tissues which on occasion has apparently caused ventricular fibrillation; and accidental radio frequency burns. Though the rate of incidents is low--in terms of the number per 100 000 procedures--individual accidents tend to be fairly catastrophic and traumatic to both the patient and surgical team. Frequently, litigation results from these accidents. Though the hazards cannot be eliminated, the probability of an incident can be minimized by careful technique.

  18. Hydrocarbon fuels from gas phase decarboxylation of hydrolyzed free fatty acid

    KAUST Repository

    Wang, Weicheng

    2012-01-01

    Gas phase decarboxylation of hydrolyzed free fatty acid (FFA) from canola oil has beeninvestigated in two fix-bed reactors by changing reaction parameters such as temperatures,FFA feed rates, and H 2-to-FFA molar ratios. FFA, which contains mostly C 18 aswell as a few C 16, C 20, C 22, and C 24 FFA, was fed into the boiling zone, evaporated, carriedby hydrogen flow at the rate of 0.5-20 ml/min, and reacted with the 5% Pd/C catalystin the reactor. Reactions were conducted atmospherically at 380-450 °C and the products,qualified and quantified through gas chromatography-flame ionization detector(GC-FID), showed mostly n-heptadecane and a few portion of n-C 15, n-C 19, n-C 21, n-C 23 as well as some cracking species. Results showed that FFA conversion increased withincreasing reaction temperatures but decreased with increasing FFA feed rates and H 2-to-FFA molar ratios. The reaction rates were found to decrease with higher temperatureand increase with higher H 2 flow rates. Highly selective heptadecane was achieved byapplying higher temperatures and higher H 2-to-FFA molar ratios. From the results, ascatalyst loading and FFA feed rate were fixed, an optimal reaction temperature of 415 °C as well as H 2-to-FFA molar ratio of 4.16 were presented. These results provided goodbasis for studying the kinetics of decarboxylation process. © 2012 American Society of Mechanical Engineers.

  19. Conformational preferences of γ-aminobutyric acid in the gas phase and in water

    Science.gov (United States)

    Song, Il Keun; Kang, Young Kee

    2012-09-01

    The conformational study of γ-aminobutyric acid (GABA) has been carried out at the M06-2X/cc-pVTZ level of theory in the gas phase and the SMD M06-2X/cc-pVTZ level of theory in water. In the gas phase, the folded conformation gG1 with gauche- and gauche+ conformations for the Cβsbnd Cα and Cγsbnd Cβ bonds, respectively, is found to be lowest in energy and enthalpy, which can be ascribed to the favored hyperconjugative n → π* interaction between the lone electron pair of the amine nitrogen atom and the Cdbnd O bond of the carboxylic group and the favored antiparallel dipole-dipole interaction between the Nsbnd H bond and the Cdbnd O bond. In addition, the intramolecular hydrogen bonds between the carboxylic group and the amine Nsbnd H group have contributed to stabilize some low-energy conformers. However, the most preferred conformation is found to be tG1 and more stable by 0.4 kcal/mol in ΔG than the conformer gG1, in which the favored entropic term due to the conformational flexibility and the other favored n → σ*, σ → σ*, and π → σ* interactions seem to play a role. The conformational preferences of the neutral GABA calculated by ΔG's are reasonably consistent with the populations deduced from FT microwave spectroscopy in supersonic jets combined with laser ablation. In water, the two folded conformers Gg and gG of the zwitterionic GABA are dominantly populated, each of which has the population of 47%, and the hydrogen bond between the ammonium Nsbnd H group and the lone electron pair of the Csbnd O- group seems to be crucial in stabilizing these conformers. Our calculated result that the folded conformers preferentially exist in water is consistent with the 1H NMR experiments in D2O.

  20. Gas phase acetic acid and its qualitative effects on snow crystal morphology and the quasi-liquid layer

    Directory of Open Access Journals (Sweden)

    T. N. Knepp

    2009-10-01

    Full Text Available A chamber was constructed within which snow crystals were grown on a string at various temperatures, relative humidities, and acetic acid gas phase mole fractions. The temperature, relative humidity, and acid mole fraction were measured for the first time at the point of crystal growth. Snow crystal morphological transition temperature shifts were recorded as a function of acid mole fraction, and interpreted according to the calculated acid concentration in the crystal's quasi-liquid layer, which is believed to have increased in thickness as a function of acid mole fraction, thereby affecting the crystal's morphology consistent with the hypothesis of Kuroda and Lacmann. Deficiencies in the understanding of the quasi-liquid layer and its role in determining snow crystal morphology are briefly discussed.

  1. Multiple heavy metals extraction and recovery from hazardous electroplating sludge waste via ultrasonically enhanced two-stage acid leaching.

    Science.gov (United States)

    Li, Chuncheng; Xie, Fengchun; Ma, Yang; Cai, Tingting; Li, Haiying; Huang, Zhiyuan; Yuan, Gaoqing

    2010-06-15

    An ultrasonically enhanced two-stage acid leaching process on extracting and recovering multiple heavy metals from actual electroplating sludge was studied in lab tests. It provided an effective technique for separation of valuable metals (Cu, Ni and Zn) from less valuable metals (Fe and Cr) in electroplating sludge. The efficiency of the process had been measured with the leaching efficiencies and recovery rates of the metals. Enhanced by ultrasonic power, the first-stage acid leaching demonstrated leaching rates of 96.72%, 97.77%, 98.00%, 53.03%, and 0.44% for Cu, Ni, Zn, Cr, and Fe respectively, effectively separated half of Cr and almost all of Fe from mixed metals. The subsequent second-stage leaching achieved leaching rates of 75.03%, 81.05%, 81.39%, 1.02%, and 0% for Cu, Ni, Zn, Cr, and Fe that further separated Cu, Ni, and Zn from mixed metals. With the stabilized two-stage ultrasonically enhanced leaching, the resulting over all recovery rates of Cu, Ni, Zn, Cr and Fe from electroplating sludge could be achieved at 97.42%, 98.46%, 98.63%, 98.32% and 100% respectively, with Cr and Fe in solids and the rest of the metals in an aqueous solution discharged from the leaching system. The process performance parameters studied were pH, ultrasonic power, and contact time. The results were also confirmed in an industrial pilot-scale test, and same high metal recoveries were performed.

  2. Identification and quantitation of urinary dicarboxylic acids as their dicyclohexyl esters in disease states by gas chromatography mass spectrometry.

    Science.gov (United States)

    Norman, E J; Berry, H K; Denton, M D

    1979-12-01

    Clinical studies were conducted by gas chromatography mass spectrometry selected ion monitoring of urinary dicarboxylic acids as dicyclohexyl esters. The dicyclohexyl esters of the dicarboxylic acids give characteristic electron impact mass spectra suitable for selected ion monitoring. The mass spectra exhibit a prominent acid + 1H ion and an (acid + 1H)-H2O ion for use as quantitating and confirming ions. The cyclohexyl esters are stable for days at room temperature and have excellent chromatographic properties. Dicarboxylic acid quantitation is performed within one hour using only 50 microliter of unpurified urine. A rapid method specifically for methylmalonic acid quantitation is described which has assisted physicians in the diagnosis of pernicious anemia and methylmalonic aciduria. This procedure is applicable for screening urinary organic acids for detection of inborn errors of metabolism. The detection of a child with elevated medium length dicarboxylic acids in the terminal urine specimen is reported. This condition, previously described as an inborn error, is attributed to a terminal event. Finally, an increase in urinary succinic acid paralleling putrescine levels is described during a response to cancer chemotherapy.

  3. Separation of cis/trans fatty acid isomers on gas chromatography compared to the Ag-TLC method

    Energy Technology Data Exchange (ETDEWEB)

    Ravi Kiran, C.; Reshma, M. V.; Sundaresan, A.

    2013-05-01

    The present study investigates the separation of the cis/ trans isomers of fatty acids on the 75 m SP2560 column under different gas chromatographic (GC) conditions including an isothermal program and a time-temperature program. The time-temperature program showed improved separation of cis/trans isomers of C{sub 1}4:1, C{sub 1}6:1, C{sub 1}8:1, C{sub 1}8:2 and C{sub 1}8:3 fatty acids along with short chain fatty acids compared to the isothermal program. The separation of trans/trans isomers of C{sub 1}8:1 fatty acids including elaidic acid (C{sub 1}8:1 .9t) and vaccenic acid (C{sub 1}8:1 {Delta}11t) was difficult with the time-temperature program. The thin layer chromatography impregnated with silver nitrate (Ag- TLC) method was performed to separate cis/trans fractions and GC analysis was carried out with the trans fraction. But GC analysis showed a co-elution of trans isomers of C{sub 1}8:1 fatty acid. Thus the study shows that a time-temperature programmed GC method with the highly polar cyanopropyl column is sufficient to resolve trans fatty acids along with short chain fatty acids when a large number of samples has to be analyzed. (Author) 33 refs.

  4. Gas Chromatographic Analysis of Medium Chain Fatty Acids in Coconut Oil

    Directory of Open Access Journals (Sweden)

    Julius Pontoh

    2016-09-01

    Full Text Available Analysis of medium chain of fatty acids in coconut oil becomes important due to their roles in health issues. The present analysis methods for fatty acids present in food mainly focused to the overall fatty acid concentration. The analytical method for specific medium chain fatty acids is not so much be given attention. This research is focused to the analytical methods for these particular fatty acids in coconut oil. Several analytical methods were compared including acid catalyzed, basic catalyzed and acid boron trifluoride catalyzed derivatization. The response of each fatty acid toward the derivatization methods are different. Formation of the fatty acid methyl ester from caprylic and capric was low for acid catalyzed method compared to basic catalyzed method and acid boron trifluoride catalyzed methods. This finding shows that the kinetics of the esterification among the fatty acids are not the same. The analysis of all fatty acids in coconut oil is better using basic catalyzed than the other methods.

  5. Advanced Acid Gas Separation Technology for the Utilization of Low Rank Coals

    Energy Technology Data Exchange (ETDEWEB)

    Kloosterman, Jeff

    2012-12-31

    Air Products has developed a potentially ground-breaking technology – Sour Pressure Swing Adsorption (PSA) – to replace the solvent-based acid gas removal (AGR) systems currently employed to separate sulfur containing species, along with CO{sub 2} and other impurities, from gasifier syngas streams. The Sour PSA technology is based on adsorption processes that utilize pressure swing or temperature swing regeneration methods. Sour PSA technology has already been shown with higher rank coals to provide a significant reduction in the cost of CO{sub 2} capture for power generation, which should translate to a reduction in cost of electricity (COE), compared to baseline CO{sub 2} capture plant design. The objective of this project is to test the performance and capability of the adsorbents in handling tar and other impurities using a gaseous mixture generated from the gasification of lower rank, lignite coal. The results of this testing are used to generate a high-level pilot process design, and to prepare a techno-economic assessment evaluating the applicability of the technology to plants utilizing these coals.

  6. Flue gas desulfurization by-products additions to acid soil: alfalfa productivity and environmental quality

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.; Dick, W.A.; Nelson, S.

    2001-07-01

    Flue gas desulfurization (FGD) by-products are often alkaline and contain many plant nutrients. Land application of FGD by-products is encouraged but little information is available related to plant responses and environmental impacts concerning such use. Agricultural lime (ag-lime) and several new types of FGD by-products which contain either vermiculite or perlite were applied at 0, 0.5, 1.0, and 2.0 times the soil's lime requirement (LR) rate to an acidic soil (Wooster silt loam). The highest FGD by-products application rate was equivalent to 75.2 Mg ha{sup -1}. Growth of alfalfa (Medicago sativa L.) was significantly increased compared to the untreated control in the second year after treatment with yields for the 1 x LR rate of FGD approximately 7-8 times greater compared to the untreated control and 30% greater than for the commercial ag-lime. Concentrations of Mo in alfalfa were significantly increased by FGD by-products application, compared to the untreated control, while compared to the ag-lime treatment, concentrations of B increased and Ba decreased. No soil contamination problems were observed, even at the 2xLR rate, indicating these materials can be safely applied to agricultural soils.

  7. Optimizing Techology to Reduce Mercury and Acid Gas Emissions from Electric Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey C. Quick; David E. Tabet; Sharon Wakefield; Roger L. Bon

    2004-01-31

    More than 56,000 coal quality data records from five public data sets have been selected for use in this project. These data will be used to create maps showing where coals with low mercury and acid-gas emissions might be found for power plants classified by air-pollution controls. Average coal quality values, calculated for 51,156 commercial coals by U.S. county-of-origin, are listed in the appendix. Coal moisture values are calculated for commercially shipped coal from 163 U.S. counties, where the raw assay data (including mercury and chlorine values) are reported on a dry basis. The calculated moisture values are verified by comparison with observed moisture values in commercial coal. Moisture in commercial U.S. coal shows provincial variation. For example, high volatile C bituminous rank coal from the Interior province has 3% to 4% more moisture than equivalent Rocky Mountain province coal. Mott-Spooner difference values are calculated for 4,957 data records for coals collected from coal mines and exploration drill holes. About 90% of the records have Mott-Spooner difference values within {+-}250 Btu/lb.

  8. Growth of forage legumes and grasses in acidic soil amended with flue gas desulfurization products

    Energy Technology Data Exchange (ETDEWEB)

    Clark, R.B.; Baligar, V.C. [USDA ARS, Beltsville, MD (USA)

    2003-07-01

    Large amounts of flue gas desulfurization products (FGDs) are produced when SO{sub 2} emissions are trapped in the coal burning process for generation of electricity. FGDs are normally discarded instead of being reused, and reuse on soils could be important in overall management of these products. Glasshouse experiments were conducted to determine effects of various levels of three FGDs (a FGD gypsum, an oxidized FGD + Mg, and a stabilized FGD) and the control compounds CaCO{sub 3}, CaSO{sub 3}, and CaSO{sub 4} on growth of alfalfa (Medicago sativa), white clover (Trifolium repens), orchardgrass (Dactylis glomerata), tall fescue (Festuca arundinacea), switchgrass (Panicum virgatum), and eastern gamagrass (Tripsacum dactyloides) in acidic (pH 4) soil (Typic Hapludult). The FGDs enhanced growth of each plant species, with alfalfa, white clover, and tall fescue receiving greater increases than the other species, especially when grown in soil amended with FGD + Mg. FGD gypsum did not often enhance growth unless high amounts were added. FGDs containing high B and low levels of CaSO{sub 3} were detrimental to growth. Overall, FGDs improved growth responses of these forage plants grown in an infertile low pH soil.

  9. Evaluation of the potentials of humic acid removal in water by gas phase surface discharge plasma.

    Science.gov (United States)

    Wang, Tiecheng; Qu, Guangzhou; Ren, Jingyu; Yan, Qiuhe; Sun, Qiuhong; Liang, Dongli; Hu, Shibin

    2016-02-01

    Degradation of humic acid (HA), a predominant type of natural organic matter in ground water and surface waters, was conducted using a gas phase surface discharge plasma system. HA standard and two surface waters (Wetland, and Weihe River) were selected as the targets. The experimental results showed that about 90.9% of standard HA was smoothly removed within 40 min's discharge plasma treatment at discharge voltage 23.0 kV, and the removal process fitted the first-order kinetic model. Roles of some active species in HA removal were studied by evaluating the effects of solution pH and OH radical scavenger; and the results presented that O3 and OH radical played significant roles in HA removal. Scanning electron microscope (SEM) and FTIR analysis showed that HA surface topography and molecular structure were changed during discharge plasma process. The mineralization of HA was analyzed by UV-Vis spectrum, dissolved organic carbon (DOC), specific UV absorbance (SUVA), UV absorption ratios, and excitation-emission matrix (EEM) fluorescence. The formation of disinfection by-products during HA sample chlorination was also identified, and CHCl3 was detected as the main disinfection by-product, but discharge plasma treatment could suppress its formation to a certain extent. In addition, approximately 82.3% and 67.9% of UV254 were removed for the Weihe River water and the Wetland water after 40 min of discharge plasma treatment.

  10. Growth, Gas Exchange, Abscisic Acid, and Calmodulin Response to Salt Stress in Three Poplars

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In the present study, we investigated the effects of increasing salinity on growth, gas exchange, abscisic acid(ABA), calmodulin (CAM), and the relevance to salt tolerance in seedlings of Populus euphratica Oliv. and cuttings of P. "pupularis 35-44" (P. popularis) and P. x euramericana cv. 1-214 (P. cv. Italica). The relative growth rates of shoot height (RGRH) for P. cv. Italica and P. popularis were severely reduced by increasing salt stress,whereas the growth reduction was relatively less in P. euphratica. Similarly, P. euphratica maintained higher net photosynthetic rates (Pn) and unit transpiration rates (TRN) than P. cv. Italica and P. popularis under conditions of higher salinity. Salinity caused a significant increase in leaf ABA and CaM in the three genotypes after the onset of stress, but NaCl-induced ABA and CaM accumulation was more pronounced in P. euphratica,suggesting that P. euphratica plants are more sensitive in sensing soil salinity than the other two poplars.Furthermore, P. euphratica maintained relatively higher ABA and CaM concentrations under conditions of high salinity. The higher capacity to synthesize stress signals, namely ABA and CaM, in P. euphratica and the contribution of this to the salt resistance of P. euphratica are discussed.

  11. Hazardous waste to materials: recovery of molybdenum and vanadium from acidic leach liquor of spent hydroprocessing catalyst using alamine 308.

    Science.gov (United States)

    Sahu, K K; Agrawal, Archana; Mishra, D

    2013-08-15

    Recovery of valuable materials/metals from waste goes hand in hand with environmental protection. This paper deals with the development of a process for the recovery of metals such as Mo, V, Ni, Al from spent hydroprocessing catalyst which may otherwise cause a nuisance if dumped untreated. A detailed study on the separation of molybdenum and vanadium from the leach solution of spent hydroprocessing catalyst of composition: 27.15% MoO₃, 1.7% V₂O₅, 3.75% NiO, 54.3% Al₂O₃, 2.3% SiO₂ and 10.4% LOI is reported in this paper. The catalyst was subjected to roasting under oxidizing atmosphere at a temperature of about 550 °C and leaching in dilute sulphuric acid to dissolve molybdenum, vanadium, nickel and part of aluminium. Metals from the leach solution were separated by solvent extraction. Both molybdenum and vanadium were selectively extracted with a suitable organic solvent leaving nickel and dissolved aluminium in the raffinate. Various parameters such as initial pH of the aqueous feed, organic to aqueous ratio (O:A), solvent concentration etc. were optimized for the complete extraction and recovery of Mo and V. Molybdenum and vanadium from the loaded organic were stripped by ammonia solution. They were recovered as their corresponding ammonium salt by selective precipitation, and were further calcined to get the corresponding oxides in pure form.

  12. Urinary 3-methoxy-4-hydroxyphenylacetic (homovanillic) and 3-methoxy-4-hydroxymandelic (vanillylmandelic) acids: gas-liquid chromatographic methods and experience with 13 cases of neuroblastoma.

    Science.gov (United States)

    Brewster, M A; Berry, D H; Moriarty, M

    1977-12-01

    We present a quantitative gas-chromatographic method for determining urinary 3-methoxy-4-hydroxymandelic acid (vanillylmandelic acid) and 3-methoxy-4-hydroxyphenylacetic acid (homovanillic acid). In this rapid technique an internal standard is used and the procedure involves ether extraction and silyl ether formation. Analytical recovery of vanillylmandelic acid averages 87.5% (CV, 0.95%), of homovanillic acid 102.3% (CV, 9.95%). Our data on 34 samples from 13 neuroblastoma patients show that homovanillic acid is more consistently elevated than is vanillylmandelic acid.

  13. Factors affecting variations in the detailed fatty acid profile of Mediterranean buffalo milk determined by 2-dimensional gas chromatography.

    Science.gov (United States)

    Pegolo, S; Stocco, G; Mele, M; Schiavon, S; Bittante, G; Cecchinato, A

    2017-04-01

    Buffalo milk is the world's second most widely produced milk, and increasing attention is being paid to its composition, particularly the fatty acid profile. The objectives of the present study were (1) to characterize the fatty acid composition of Mediterranean buffalo milk, and (2) to investigate potential sources of variation in the buffalo milk fatty acid profile. We determined the profile of 69 fatty acid traits in 272 individual samples of Mediterranean buffalo milk using gas chromatography. In total, 51 individual fatty acids were identified: 24 saturated fatty acids, 13 monounsaturated fatty acids, and 14 polyunsaturated fatty acids. The major individual fatty acids in buffalo milk were in the order 16:0, 18:1 cis-9, 14:0, and 18:0. Saturated fatty acids were the predominant fraction in buffalo milk fat (70.49%); monounsaturated and polyunsaturated fatty acids were at 25.95 and 3.54%, respectively. Adopting a classification based on carbon-chain length, we found that medium-chain fatty acids (11-16 carbons) represented the greater part (53.7%) of the fatty acid fraction of buffalo milk, whereas long-chain fatty acids (17-24 carbons) and short-chain fatty acids (4-10 carbons) accounted for 32.73 and 9.72%, respectively. The n-3 and n-6 fatty acids were 0.46 and 1.77%, respectively. The main conjugated linoleic acid, rumenic acid, represented 0.45% of total milk fatty acids. Herd/test date and stage of lactation were confirmed as important sources of variation in the fatty acid profile of buffalo milk. The percentages of short-chain and medium-chain fatty acids in buffalo milk increased in early lactation (+0.6 and +3.5%, respectively), whereas long-chain fatty acids decreased (-4.2%). The only exception to this pattern was butyric acid, which linearly decreased from the beginning of lactation, confirmation that its synthesis is independent of malonyl-CoA. These results seem to suggest that in early lactation the mobilization of energy reserves may have less

  14. Hazardous Chemicals

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

    Chemicals are a part of our daily lives, providing many products and modern conveniences. With more than three decades of experience, The Centers for Disease Control and Prevention (CDC) has been in the forefront of efforts to protect and assess people's exposure to environmental and hazardous chemicals. This report provides information about hazardous chemicals and useful tips on how to protect you and your family from harmful exposure.  Created: 4/10/2007 by CDC National Center for Environmental Health.   Date Released: 4/13/2007.

  15. Extreme environments in the critical zone: Linking acidification hazard of acid sulfate soils in mound spring discharge zones to groundwater evolution and mantle degassing.

    Science.gov (United States)

    Shand, Paul; Gotch, Travis; Love, Andrew; Raven, Mark; Priestley, Stacey; Grocke, Sonia

    2016-10-15

    A decrease in flow from the iconic travertine mound springs of the Great Artesian Basin in South Australia has led to the oxidation of hypersulfidic soils and extreme soil acidification, impacting their unique groundwater dependent ecosystems. The build-up of pyrite in these systems occurred over millennia by the discharge of deep artesian sulfate-containing groundwaters through organic-rich subaqueous soils. Rare iron and aluminium hydroxysulfate minerals form thick efflorescences due to high evaporation rates in this arid zone environment, and the oxidised soils pose a significant risk to local aquatic and terrestrial ecosystems. The distribution of extreme acidification hazard is controlled by regional variations in the hydrochemistry of groundwater. Geochemical processes fractionate acidity and alkalinity into separate parts of the discharge zone allowing potentially extreme environments to form locally. Differences in groundwater chemistry in the aquifer along flow pathways towards the spring discharge zone are related to a range of processes including mineral dissolution and redox reactions, which in turn are strongly influenced by degassing of the mantle along deep crustal fractures. There is thus a connection between shallow critical zone ecosystems and deep crustal/mantle processes which ultimately control the formation of hypersulfidic soils and the potential for extreme geochemical environments.

  16. Gas chromatographic separation of fatty acid esters of cholesterol and phytosterols on an ionic liquid capillary column.

    Science.gov (United States)

    Hammann, Simon; Vetter, Walter

    2015-12-15

    Steryl esters are high molecular weight compounds (600-700g/mol) regularly present as a minor lipid class in animal and plant lipids. Different sterol backbones (e.g., cholesterol, β-sitosterol and brassicasterol) which can be esterified with various fatty acids can result in highly complex steryl ester patterns in food samples. The gas chromatographic (GC) analysis of intact steryl esters is challenging, since high elution temperatures are required for their elution. On nonpolar GC phases, steryl esters with fatty acids with differing degree of unsaturation (e.g., oleate and linoleate) cannot be separated and there are only few polar columns available with sufficient temperature stability. In this study, we used gas chromatography with mass spectrometry (GC/MS) and analyzed intact steryl esters on a commercial room temperature ionic liquid (RTIL) column which was shortened to a length of 12m. The column separated the steryl esters both by total carbon number and by degree of unsaturation of the fatty acid. For instance, cholesteryl esters with stearic acid (18:0), oleic acid (18:1n-9), linoleic acid (18:2n-6) and α-linolenic acid (18:3n-3) could be resolved (R≥1.3) from each other. By analysis of synthesized standard substances, the elution orders for different steryl backbones and different fatty acids on a given sterol backbone could be determined. Analysis of spreads and plant oils allowed to determine retention times for 37 steryl esters, although a few co-elutions were observed. The ionic liquid column proved to be well-suited for the analysis of intact steryl esters.

  17. [Analysis of fatty acids in Gmnocypris przewalskii oil by gas chromatography/mass spectrometry with base-catalyzed transesterification].

    Science.gov (United States)

    Bo, Haibo; Wang, Xia; Zhai, Zongde; Li, Yongmin; Chen, Liren

    2006-03-01

    The composition of fatty acids (FA) in Gymnocypris przewalskii oil was identified and quantified by gas chromatography (GC)/electron impact (EI) mass spectrometry (MS). A base-catalyzed transesterification method was used to convert fatty acids to methyl esters. The lipids were extracted using petroleum ether and the total lipids in dried meat and skin of Gymnocypris przewalskii were about 25%. Forty-seven fatty acids were identified in the current study. Main types of fatty acids found in the oils were normal saturated, mono-branched, multi-branched, cyclopropane, furanoid, normal monounsaturated and polyunsaturated fatty acids. Saturated fatty acids were approximately 25. 7% of the total, and the main components were C(14:0) (3.4%), C(16:0) (19.4%) and C(18:0) (1.1%). Unsaturated fatty acids were totally 73.6%, and the major components of monounsaturated fatty acids were C(16:1 (9)) (19.8%), C(18:1) (9)) (18. 6%) and C(18:1 (11)) (7.3%); polyunsaturated fatty acids were mainly composed of C(18:2 (9,12)) (4.8%), C(18:3 (9, 12, 15)) (3.1%), C(20:4 (5, 8, 1, 14)) (1.2%), C(20:5 (5, 8, 11, 14, 17)) (EPA, 9.4%) and C(22:6 (4, 7, 10, 13, 16, 19)) (DHA, 6.7%). Especially, furyl-, cyclopropane- and several odd and branched chain fatty acids were found in Gymnocypris przewalskii oil. It is thus an important dietary resource of functional fatty acids.

  18. Gas chromatography of alkylphosphonic and dialkyl phosphinic acids; Cromatografia en fase gaseosa de acidos alquifosfonicos y dialquilfosinicos

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L.; Barrera Peniero, R.; Ramirez Caceres, A.; Marin Munoz, M.

    1978-07-01

    After carrying out an optimization study on the separation conditions for the TMSr- derivatives, of the hexyl-, cyclohexyl-, heptyl-, and octyl-phosphonic acids; dihexyl dicyclohexyl-, heptyl-, and octyl-phosphinic acids, and dioctyl phosphine oxide, their retention indices (I) at two temperatures and on the OV-1 and OV-17 stationary phase were determined. Correlations between I and molecular structure were established. Calibration factors of these compounds in the flame ionization detector were studied, and the results analyzed taking into account the variables affecting the quantitative results, These results were unbiased but they had a lower precision than that usually achievable in gas chromatography. (Author) 24 refs.

  19. Comparison of gas chromatographic and gravimetric methods for quantization of total fat and fatty acids in foodstuffs

    Directory of Open Access Journals (Sweden)

    Sabria Aued-Pimentel

    2010-01-01

    Full Text Available Different methods to determine total fat (TF and fatty acids (FA, including trans fatty acids (TFA, in diverse foodstuffs were evaluated, incorporating gravimetric methods and gas chromatography with flame ionization detector (GC/FID, in accordance with a modified AOAC 996.06 method. Concentrations of TF and FA obtained through these different procedures diverged (p< 0.05 and TFA concentrations varied beyond 20 % of the reference values. The modified AOAC 996.06 method satisfied both accuracy and precision, was fast and employed small amounts of low toxicity solvents. Therefore, the results showed that this methodology is viable to be adopted in Brazil for nutritional labeling purposes.

  20. [Study of the fatty acid components of the triglyceride fraction of the blood in normal and thalassemic subjects, using gas chromatography].

    Science.gov (United States)

    Gilli, G; Moiraghi Ruggenini, A; Nani, E; Bottura, G; Mastretta, L

    1977-01-01

    Thin layer chromatography was used to separate the triglyceridic fraction of plasma lipides in normal (19) and thalassaemic (15) subjects. Gas chromatographic analysis of the fraction was then carried out and the fatty acids represented were identified qualitatively and quantitatively. Statistically significant variations, specifically increase in arachidonic acid and reduction in palmitic and linoleic acids, were observed in the thalassaemic patients.

  1. Genetic and environmental relationships of detailed milk fatty acids profile determined by gas chromatography in Brown Swiss cows.

    Science.gov (United States)

    Pegolo, S; Cecchinato, A; Casellas, J; Conte, G; Mele, M; Schiavon, S; Bittante, G

    2016-02-01

    The aim of this study was to characterize the profile of 47 fatty acids, including conjugated linoleic acid (CLA), 13 fatty acid groups, and 5 Δ(9)-desaturation indices in milk samples from Brown Swiss cows. The genetic variation was assessed and the statistical relevance of the genetic background for each trait was evaluated using the Bayes factor test. The additive genetic, herd-date, and residual relationships were also estimated among all single fatty acids and groups of fatty acids. Individual milk samples were collected from 1,158 Italian Brown Swiss cows and a detailed analysis of fat percentages and milk fatty acid compositions was performed by gas chromatography. Bayesian animal models were used for (co)variance components estimation. Exploitable genetic variation was observed for most of the de novo synthesized fatty acids and saturated fatty acids, except for C4:0 and C6:0, whereas long-chain fatty acids and unsaturated fatty acids (including CLA) were mainly influenced by herd-date effects. Herd-date effect explained large portions of the total phenotypic variance for C18:2 cis-9,cis-12 (0.668), C18:3 cis-9,cis-12,cis-15 (0.631), and the biohydrogenation and elongation products of these fatty acids. The desaturation ratios showed higher heritability estimates than the individual fatty acids, except for CLA desaturation index (0.098). Among the medium-chain fatty acids, C12:0 had greater heritability than C14:0 (0.243 vs. 0.097, respectively). Both C14:0 and C16:0 showed negative additive genetic correlations with the main monounsaturated and polyunsaturated fatty acids of milk fat, suggesting that their synthesis in the mammary gland may be influenced by the presence of unsaturated fatty acids. No correlation was observed between C4:0 and the other short-chain fatty acids (except for C6:0), confirming the independence of C4:0 from de novo mammary fatty acid synthesis. Among the genetic correlations dealing with potentially beneficial fatty acids, C18

  2. Investigation of Gas-Sensing Property of Acid-Deposited Polyaniline Thin-Film Sensors for Detecting H2S and SO2

    Directory of Open Access Journals (Sweden)

    Xingchen Dong

    2016-11-01

    Full Text Available Latent insulation defects introduced in manufacturing process of gas-insulated switchgears can lead to partial discharge during long-time operation, even to insulation fault if partial discharge develops further. Monitoring of decomposed components of SF6, insulating medium of gas-insulated switchgear, is a feasible method of early-warning to avoid the occurrence of sudden fault. Polyaniline thin-film with protonic acid deposited possesses wide application prospects in the gas-sensing field. Polyaniline thin-film sensors with only sulfosalicylic acid deposited and with both hydrochloric acid and sulfosalicylic acid deposited were prepared by chemical oxidative polymerization method. Gas-sensing experiment was carried out to test properties of new sensors when exposed to H2S and SO2, two decomposed products of SF6 under discharge. The gas-sensing properties of these two sensors were compared with that of a hydrochloric acid deposited sensor. Results show that the hydrochloric acid and sulfosalicylic acid deposited polyaniline thin-film sensor shows the most outstanding sensitivity and selectivity to H2S and SO2 when concentration of gases range from 10 to 100 μL/L, with sensitivity changing linearly with concentration of gases. The sensor also possesses excellent long-time and thermal stability. This research lays the foundation for preparing practical gas-sensing devices to detect H2S and SO2 in gas-insulated switchgears at room temperature.

  3. Interactions of Gas-Phase Nitric/Nitrous Acids and Primary Organic Aerosol in the Atmosphere of Houston, TX

    Science.gov (United States)

    Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Whitlow, S. I.; Lefer, B. L.; Flynn, J.; Rappenglück, B.

    2007-12-01

    Concentrations of aerosol and gas-phase pollutants were measured on the roof of an 18-story building during the Texas Air Quality Study II Radical and Aerosol Measurement Project (TRAMP) from August 15 through September 28, 2006. Aerosol measurements included size-resolved, non-refractory mass concentrations of ammonium, nitrate, sulfate, chloride, and organic aerosol in submicron particles using an Aerodyne quadrupole aerosol mass spectrometer (Q-AMS). Particulate water-soluble organic carbon (PWSOC) was quantified using a mist chamber/total organic carbon analysis system. Concentration data for gas-phase pollutants included those for nitric acid (HNO3), nitrous acid (HONO), and hydrochloric acid (HCl) collected using a mist chamber/ion chromatographic technique, oxides of nitrogen (NOx) collected using a chemiluminescent method, and carbon monoxide (CO) collected using an infrared gas correlation wheel instrument. Coincident increases in nitrate and organic aerosol mass concentrations were observed on many occasions throughout the measurement campaign, most frequently during the morning rush hour. Based on the lack of organic aerosol processing (defined by the ratio of m/z = 44/57 in the Q-AMS spectra), strong correlation with NOx and CO, and a lack of significant increase in PWSOC concentration, the spikes in organic aerosol were likely associated with primary organic aerosol (POA). During these events, gas-phase HNO3 concentration decreases were observed simultaneously with increases in gas-phase HONO concentrations. These data likely indicate uptake of HNO3 and subsequent heterogeneous conversion to HONO involving POA. Preliminary calculations show that HNO3 partitioning could account for the majority of the observed HONO and aerosol nitrate concentrations during these events. Q-AMS chloride and HCl data also indicate uptake of chloride by particles during these events. This phenomenon was also observed during the night, but these nocturnal events were less

  4. Effect of gas saturation conditions on the expansion ratio of microcellular poly(lactic acid/wood-flour composites

    Directory of Open Access Journals (Sweden)

    2010-10-01

    Full Text Available Poly(lactic acid or PLA and PLA/wood-flour composites were microcellular foamed with CO2 through a batch foaming process. Specifically, the gas saturation pressure and time varied during processing to produce PLA foams with a high expansion ratio. A ten fold expansion ratio resulted in microcellular foamed PLA over unfoamed counterpart. The foaming conditions associated with such a high expansion ratio involved a lower gas saturation pressure up to 2.76 MPa, which corresponds to a critical gas concentration of approximately 9.4%. Beyond this critical value, foam expansion decreased significantly. Investigations also studied the effect of incorporating wood flour on the foamability of the resulting PLA/wood-flour composites. The addition of wood flour into the PLA matrix significantly affected the expansion ratio of PLA/wood-flour composite foams.

  5. Unusual hydrogen and hydroxyl migration in the fragmentation of excited doubly-positively-charged amino acids in the gas phase

    OpenAIRE

    Díaz-Tendero, Sergio; Piekarski, Dariusz G.; Alcamí, Manuel; Martín, Fernando; Maclot, Sylvain; Delaunay, Rudy; Domaracka, Alicja; Rousseau, Patrick; Adoui, Lamri; Huber, Bernd A.

    2015-01-01

    We present a combined experimental and theoretical study of the fragmentation of doubly-positively- charged amino acids in the gas phase. The combination of ab initio molecular dynamics simulations with ion- molecule collisions followed by multiple-coincidence mass spectrometric techniques, allows us to obtain a complete picture of the fragmentation dynamics. In addition to the expected Coulomb explosion, we have found evidence of hydrogen and hydroxyl-group migration processes, which leads t...

  6. Preparing ultrafine PbS powders from the scrap lead-acid battery by sulfurization and inert gas condensation

    Science.gov (United States)

    Xia, Huipeng; Zhan, Lu; Xie, Bing

    2017-02-01

    A novel method for preparing ultrafine PbS powders involving sulfurization combined with inert gas condensation is developed in this paper, which is applicable to recycle Pb from lead paste of spent lead-acid batteries. Initially, the effects of the evaporation and condensation temperature, the inert gas pressure, the condensation distance and substrate on the morphology of as-obtained PbS ultrafine particles are intensively investigated using sulfur powders and lead particles as reagents. Highly dispersed and homogeneous PbS nanoparticles can be prepared under the optimized conditions which are 1223 K heating temperature, 573 K condensation temperature, 100 Pa inert gas pressure and 60 cm condensation distance. Furthermore, this method is successfully applied to recycle Pb from the lead paste of spent lead acid battery to prepare PbS ultrafine powders. This work does not only provide the theoretical fundamental for PbS preparation, but also provides a novel and efficient method for recycling spent lead-acid battery with high added-value products.

  7. Detection of atypical bile acids in disease states and their identification by gas chromatography-mass spectrometry-computer techniques

    Energy Technology Data Exchange (ETDEWEB)

    Szczepanik-Van Leeuwen, P. A.; Stellaard, F.

    1978-01-01

    The study of the bile acid constituents of serum, bile, urine, and stool of patients exhibiting liver disease has increased in importance with the availability of newer methods for their detection and identification. A cogent question for study has been whether specific bile acids are toxic and thus are the cause of liver disease, or whether they accumulate as a result of disease-induced alteration in metabolism. Examining a wide variety of clinical samples, we have observed that many patients with diagnosed cholestasis show the presence of atypical bile acids due to metabolic aberrations in either the side chain or in the steroid ring. Because cholestasis represents a spectrum of diseases with differing metabolic and/or anatomic defects and because our studies cover a variety of cholestatic states, we have sought to establish a correlation between the presence of these atypical bile acids and the disease state. The complexity of the bile acid mixtures to be examined requires that gas chromatographic-mass spectrometric-computer techniques be used to provide a reliable analysis. It is believed that atypical bile acids can be readily identified by GC/CI mass spectrometry with great sensitivity. It is also believed that such bile acid analysis may prove useful to the study and diagnosis of liver disease. Present data suggest that the identification of atypical bile acids in biological samples may enable differentiation between different types of intrahepatic cholestasis. Such analyses may prove useful to distinguish specific diseases, such as Byler's disease (and Byler's-like cholestasis) from other types of cholestasis and may distinguish diseases involving mitochondrial defects. Finally, the presence of atypical bile acids may indicate, by the particular compounds formed, where and what kind of damage occurs in a disease and may ultimately establish if these atypical bile acids are a cause or effect of the liver damage.

  8. Decomposition of organochlorine compounds in flue gas from municipal solid waste incinerators using natural and activated acid clays.

    Science.gov (United States)

    Hwang, In-Hee; Takahashi, Shigetoshi; Matsuo, Takayuki; Matsuto, Toshihiko

    2014-09-01

    High-temperature particle control (HTPC) using a ceramic filter is a dust collection method without inefficient cooling and reheating of flue gas treatment; thus, its use is expected to improve the energy recovery efficiency of municipal solid waste incinerators (MSWIs). However there are concerns regarding de novo synthesis and a decrease in the adsorptive removal efficiency of dioxins (DXNs) at approximately 300 degrees C. In this study, the effect of natural and activated acid clays on the decomposition of monochlorobenzene (MCB), one of the organochlorine compounds in MSW flue gas, was investigated. From the results of MCB removal tests at 30-300 degrees C, the clays were classified as adsorption, decomposition, and low removal types. More than half of the clays (four kinds of natural acid clays and two kinds of activated acid clays) were of the decomposition type. In addition, the presence of Cl atoms detached from MCB was confirmed by washing the clay used in the MCB removal test at 300 degrees C. Activated acid clay was expected to have high dechlorination performance because of its proton-rich-composition, but only two clays were classed as decomposition type. Conversely, all the natural acid clays used in this work were of the decomposition type, which contained relatively higher di- and trivalent metal oxides such as Al2O3, Fe2O3, MgO, and CaO. These metal oxides might contribute to the catalytic dechlorination of MCB at 300 degrees C. Therefore, natural and activated acid clays can be used as alternatives for activated carbon at 300 degrees C to remove organochloride compounds such as DXNs. Their utilization is expected to mitigate the latent risks related to the adoption of HTPC, and also to contribute to the improvement of energy recovery efficiency of MSWI. Implications: The effect of natural and activated acid clays on MCB decomposition was investigated to evaluate their suitability as materials for the removal of organochlorine compounds, such as

  9. Effects of candidate gene polymorphisms on the detailed fatty acids profile determined by gas chromatography in bovine milk.

    Science.gov (United States)

    Pegolo, S; Cecchinato, A; Mele, M; Conte, G; Schiavon, S; Bittante, G

    2016-06-01

    Association analyses between candidate genes and bovine milk fatty acids can improve our understanding of genetic variation in milk fatty acid profiles and reveal potential opportunities to tailor milk fat composition through selection strategies. In this work, we investigated the association of 51 single nucleotide polymorphisms (SNP) selected from 37 candidate genes using a functional and positional approach, with 47 fatty acids, 9 fatty acid groups, and 5 Δ(9)-desaturation indices in milk samples from Brown Swiss cows. Individual milk samples were collected from 1,158 Italian Brown Swiss cows, and gas chromatography was used to obtain detailed milk fatty acid compositions. A GoldenGate assay system (Illumina, San Diego, CA) was used to perform genotype 96 selected SNP located in 54 genes across 22 chromosomes. In total, 51 polymorphic SNP in 37 candidate genes were retained for the association analysis. A Bayesian linear animal model was used to estimate the contribution of each SNP. A total of 129 tests indicated relevant additive effects between a given SNP and a single fatty acid trait; 38 SNP belonging to 30 genes were relevant for a total of 57 fatty acid traits. Most of the studied fatty acid traits (~81%) were relevantly associated with multiple SNP. Relevantly associated SNP were mainly found in genes related to fat metabolism, linked to or contained in previously identified quantitative trait loci for fat yield or content, or associated with genes previously identified in association analyses with milk fatty acid profiles in other cow breeds. The most representative candidate genes were LEP, PRL, STAT5A, CCL3, ACACA, GHR, ADRB2, LPIN1, STAT1, FABP4, and CSN2. In particular, relevant associations with SNP located on bovine chromosome 19 (BTA19) were found. Two candidate genes on BTA19 (CCL3 and ACACA) were relevantly associated with de novo short- and medium-chain fatty acids, likely explaining the high heritability values found for these fatty acids

  10. Fluoro- and perfluoralkylsulfonylpentafluoroanilides: synthesis and characterization of NH acids for weakly coordinating anions and their gas-phase and solution acidities.

    Science.gov (United States)

    Kögel, Julius F; Linder, Thomas; Schröder, Fabian G; Sundermeyer, Jörg; Goll, Sascha K; Himmel, Daniel; Krossing, Ingo; Kütt, Karl; Saame, Jaan; Leito, Ivo

    2015-04-01

    Fluoro- and perfluoralkylsulfonyl pentafluoroanilides [HN(C6F5)(SO2X); X = F, CF3, C4F9, C8F17] are a class of imides with two different strongly electron-withdrawing substituents attached to a nitrogen atom. They are NH acids, the unsymmetrical hybrids of the well-known symmetrical bissulfonylimides and bispentafluorophenylamine. The syntheses, the structures of these perfluoroanilides, their solvates, and some selected lithium salts give rise to a structural variety beyond the symmetrical parent compounds. The acidities of representative subsets of these novel NH acids have been investigated experimentally and quantum-chemically and their gas-phase acidities (GAs) are reported, as well as the pKa values of these compounds in acetonitrile (MeCN) and DMSO solution. In quantum chemical investigations with the vertical and relaxed COSMO cluster-continuum models (vCCC/rCCC), the unusual situation is encountered that the DMSO-solvated acid Me2SO-H-N(SO2CF3)2, optimized in the gas phase (vCCC model), dissociates to Me2SO-H(+)-N(SO2CF3)2(-) during structural relaxation and full optimization with the solvation model turned on (rCCC model). This proton transfer underlines the extremely high acidity of HN(SO2CF3)2. The importance of this effect is studied computationally in DMSO and MeCN solution. Usually this effect is less pronounced in MeCN and is of higher importance in the more basic solvent DMSO. Nevertheless, the neglect of the structural relaxation upon solvation causes typical changes in the computational pKa values of 1 to 4 orders of magnitude (4-20 kJ mol(-1)). The results provide evidence that the published experimental DMSO pKa value of HN(SO2CF3)2 should rather be interpreted as the pKa of a Me2SO-H(+)-N(SO2CF3)2(-) contact ion pair.

  11. Numerical Simulation on Hazard Zone Determination During the Dispersion of Natural Gas Containing Carbon Dioxide%含二氧化碳天然气云团扩散危险区域确定的数值模拟

    Institute of Scientific and Technical Information of China (English)

    马世海; 黄平; 杨智超; 蔡晓军

    2011-01-01

    The explosion characteristics and hazards caused by dispersion of the natural gas containing carbon dioxide are concerned about. In order to confirm the hazard zone determination during the dispersion of natural gas containing carbon dioxide, explosion characteristics and the accuracy evaluation for the numerical model, mechanism of the puff dispersion and dispersion issues caused by blowout were investigated by numerical simulation methods. A dispersion model of natural gas containing carbon dioxide was set up, and the dispersion evolvement was researched in detail, furthermore, the hazard zone concluding asphyxiation and explosion or flammability is defined. The numerical simulation results show that the flammability zone caused by the puff dispersion of the natural gas containing carbon dioxide takes on an irregular cirque distribution. Along-wind variation of flammability-zone dimension is larger than that for crosswind. For both cases of along-wind and crosswind, the distribution of variations of flammability zone with time presents the shape of parabola whose peak point is up. Besides, it does not matter to judge explosive zone based on time or on space, the affected area for flammability zone is way smaller than that for the asphyxia zone.%为确定含二氧化碳天然气云团扩散的危险区域范围,借助数值模拟方法建立了含二氧化碳天然气云团扩散模型.详细研究了含二氧化碳天然气云团扩散过程,确定了包括窒息和燃爆在内的2种危险区域.研究结果表明,含二氧化碳天然气云团扩散中燃爆区域呈不规则圆环状分布,燃爆区域的横风向尺度变化不大,而平行于风向的方向变化较大.无论横风向还是顺风向,燃爆区域尺度随时间的变化都呈开口朝下的抛物线形分布.高含二氧化碳天然气云团扩散后形成的燃爆区域无论从时间还是空间尺度看,波及的范围都远小于窒息性危险区域.

  12. Gas-phase enthalpies of formation and enthalpies of sublimation of amino acids based on isodesmic reaction calculations.

    Science.gov (United States)

    Dorofeeva, Olga V; Ryzhova, Oxana N

    2014-05-15

    Accurate gas-phase enthalpies of formation (ΔfH298°) of 20 common α-amino acids, seven uncommon amino acids, and three small peptides were calculated by combining G4 theory calculations with an isodesmic reaction approach. The internal consistency over a set of ΔfH298°(g) values was achieved by sequential adjustment of their values through the isodesmic reactions. Four amino acids, alanine, β-alanine, sarcosine, and glycine, with reliable internally self-consistent experimental data, were chosen as the key reference compounds. These amino acids together with about 100 compounds with reliable experimental data (their accuracy was supported by G4 calculations) were used to estimate the enthalpies of formation of remaining amino acids. All of the amino acids with the previously established enthalpies of formation were later used as the reference species in the isodesmic reactions for the other amino acids. A systematic comparison was made of 14 experimentally determined enthalpies of formation with the results of calculations. The experimental enthalpies of formation for 10 amino acids were reproduced with good accuracy, but the experimental and calculated values for 4 compounds differed by 11–21 kJ/mol. For these species, the theoretical ΔfH298°(g) values were suggested as more reliable than the experimental values. On the basis of theoretical results, the recommended values for the gas-phase enthalpies of formation were also provided for amino acids for which the experimental ΔfH298°(g) were not available. The enthalpies of sublimation were evaluated for all compounds by taking into account the literature data on the solid-phase enthalpies of formation and the ΔfH298°(g) values recommended in our work. A special attention was paid to the accurate prediction of enthalpies of formation of amino acids from the atomization reactions. The problems associated with conformational flexibility of these compounds and harmonic treatment of low frequency torsional

  13. 食品中乳酸菌危害因子的研究进展%Research progress on hazard factors of food - associated lactic acid bacteria

    Institute of Scientific and Technical Information of China (English)

    潘露; 胡晓清; 王小元

    2011-01-01

    Lactic acid bacteria(LAB) play an important role in food manufacturing and storage process. They not only improve food flavor and enrich food nutrition, but also have special health-care functions such as anti-aging and keeping healthy intestinal tract. However,some LAB were found to produce excessive biogenic amines,which may affect the quality of food and threat human health. Furthermore, it was revealed that some LAB carried mobile antibiotic resistant elements, which increase the risk of transferring of antibiotic resistance from LAB to other intestinal flora. Here recent researches on the biosynthesis pathway and generating mechanism ,detection methods and controlling strategies of those hazard factors of LAB were reviewed.%乳酸菌在食品加工和储存过程中具有重要作用,不仅能改善食品风味,丰富营养价值,还有维持肠道健康、延缓衰老等保健功能.但是,某些生产用乳酸菌会产生过量生物胺,影响食品感官品质,威胁人体健康,而且部分乳酸菌携带可转移耐药基因,增加了肠道菌群中耐药性水平转移的风险.综述了近年来食品中乳酸菌危害因子的合成途径和产生机制、检测方法和控制策略等.

  14. Final safety analysis addendum to hazard summary report, experimental breeder reactor No. II (EBR-II): the EBR-II cover-gas cleanup system

    Energy Technology Data Exchange (ETDEWEB)

    Fryer, R M; Monson, L R; Price, C C; Hooker, D W

    1979-04-01

    This report evaluates abnormal and accident conditions postulated for the EBR-II cover-gas cleanup system (CGCS). Major considerations include loss of CGCS function with a high level of cover-gas activity, loss of the liquid-nitrogen coolant required for removing fission products from the cover gas, contamination of the cover gas from sources other than the reactor, and loss of system pressure boundary. Calculated exposures resulting from the maximum hypothetical accident (MHA) are less than 2% of the 25-Rem limit stipulated in U.S. Regulation 10 CFR 100; i.e., a person standing at any point on an exclusion boundary (area radius of 600 m) for 2 h following onset of the postulated release would receive less than 0.45 Rem whole-body dose. The on-site whole-body dose (10 m from the source) would be less than 16 Rem.

  15. Data for generation of all Tables and Figures for AIMS-ES publication in 2016 pertaining to dry sorbent injection of trona for acid gas control

    Data.gov (United States)

    U.S. Environmental Protection Agency — emissions data and removal efficiencies for coal combustion utilizing PM control devices and dry sorbent injection of trona specifically for acid gas control. This...

  16. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    OpenAIRE

    Liu Yang; Qiang Han; Shuya Cao; Feng Huang; Molin Qin; Chenghai Guo; Mingyu Ding

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical an...

  17. Gas chromatography-mass spectrometry profile of urinary organic acids of Wistar rats orally treated with ozonized unsaturated triglycerides and ozonized sunflower oil.

    Science.gov (United States)

    Jardines, Daniel; Correa, Teresa; Ledea, Oscar; Zamora, Zullyt; Rosado, Aristides; Molerio, Jesús

    2003-01-15

    The main products in the ozonolysis of unsaturated triglycerides or vegetable oils are peroxides, aldehydes, Criegee ozonides and carboxylic acids. Some of these compounds are present in different concentrations in the biological fluids. The aim of this work is to study, using gas chromatography-mass spectrometry (GC-MS), the organic acid excretion in urine of rats orally treated with ozonized sunflower oil (OSO), ozonized triolein or ozonized trilinolein. Oral administration of OSO to Wistar rats has produced changes in the urinary content of dicarboxylic organic acids. Among others heptanedioic (pimelic acid) and nonanedioic acids (azelaic acid) were the major increased dicarboxylic acids found. The urinary dicarboxylic acid profiles of rats which received ozonized triolein only showed an increase in heptanedioic and nonanedioic acids. However, when ozonized trilinolein is applied, the profile is similar to that obtained when OSO is administered. A biochemical mechanism is proposed to explain the formation of dicarboxylic acids from ozonated unsaturated triglycerides.

  18. Pulmonary gas exchange and acid-base state at 5,260 m in high-altitude Bolivians and acclimatized lowlanders

    DEFF Research Database (Denmark)

    Wagner, Hans Peter; Araoz, Mauricio; Boushel, Robert Christopher

    2002-01-01

    Pulmonary gas exchange and acid-base state were compared in nine Danish lowlanders (L) acclimatized to 5,260 m for 9 wk and seven native Bolivian residents (N) of La Paz (altitude 3,600-4,100 m) brought acutely to this altitude. We evaluated normalcy of arterial pH and assessed pulmonary gas exch...

  19. Determination of homovanillic, isohomovanillic and vanillylmandelic acids in human urine by means of glass capillary gas-liquid chromatography with temperature-programmed electron-capture detection.

    Science.gov (United States)

    Chauhan, J; Darbre, A

    1980-10-10

    The determination of urinary homovanillic, isohomovanillic and vanillylmandelic acids as their trifluoroacetylhexafluoroisopropyl ester derivatives by glass capillary gas-liquid chromatography has been studied. It was shown that even with high column efficiencies a single peak-single compound relationship could not be assumed and for reliable quantitation it was necessary to check determinations with a second gas-liquid chromatography column.

  20. Gas flushing through hyper-acidic crater lakes: the next steps within a reframed monitoring time window

    Science.gov (United States)

    Rouwet, Dmitri

    2016-04-01

    Tracking variations in the chemical composition, water temperature and pH of brines from peak-activity crater lakes is the most obvious way to forecast phreatic activity. Volcano monitoring intrinsically implies a time window of observation that should be synchronised with the kinetics of magmatic processes, such as degassing and magma intrusion. To decipher "how much time ago" a variation in degassing regime actually occurred before eventually being detected in a crater lake is key, and depends on the lake water residence time. The above reasoning assumes that gas is preserved as anions in the lake water (SO4, Cl, F anions), in other words, that scrubbing of acid gases is complete and irreversible. Less is true. Recent work has confirmed, by direct MultiGas measurement from evaporative plumes, that even the strongest acid in liquid medium (i.e. SO2) degasses from hyper-acidic crater lakes. The less strong acid HCl has long been recognised as being more volatile than hydrophyle in extremely acidic solutions (pH near 0), through a long-term steady increase in SO4/Cl ratios in the vigorously evaporating crater lake of Poás volcano. We now know that acidic gases flush through hyper-acidic crater lake brines, but we don't know to which extend (completely or partially?), and with which speed. The chemical composition hence only reflects a transient phase of the gas flushing through the lake. In terms of volcanic surveillance this brings the advantage that the monitoring time window is definitely shorter than defined by the water chemistry, but yet, we do not know how much shorter. Empirical experiments by Capaccioni et al. (in press) have tried to tackle this kinetic problem for HCl degassing from a "lab-lake" on the short-term (2 days). With this state of the art in mind, two new monitoring strategies can be proposed to seek for precursory signals of phreatic eruptions from crater lakes: (1) Tracking variations in gas compositions, fluxes and ratios between species in

  1. Haematological, blood gas and acid-base effects of central histamine-induced reversal of critical haemorrhagic hypotension in rats.

    Science.gov (United States)

    Jochem, J

    2001-09-01

    In a rat model of volume-controlled irreversible haemorrhagic shock, which results in a severe metabolic acidosis and the death of all control animals within 30 min., intracerebroventricular injection of histamine (100 nmol) produces a prompt and long-lasting increase in mean arterial pressure and heart rate, with a 100% survival of 2 h after treatment. Histamine action is accompanied by a decrease in haematocrit value, haemoglobin concentration, erythrocyte and platelet count, and an increase in residual blood volume at the end of the experiment (2 h). Cardiovascular effects are also associated with a long-lasting rise in respiratory rate and biphasic blood acid-base changes - initial increase of metabolic acidosis with the decrease in arterial and venous pH, bicarbonate concentration and base excess, followed by almost a complete recovery of blood gas and acid-base parameters to the pre-bleeding values, with normalisation of arterial and venous pH, Pco2 bicarbonate concentration and base excess at the end of experiment. It can be concluded that in the late phase of central histamine-induced reversal of haemorrhagic hypotension there is almost a complete restoration of blood gas and acid-base status due to circulatory and respiratory compensations, while accompanying haematological changes are the result of the haemodilution and the increase in residual blood volume.

  2. Acidic methanolysis v. alkaline saponification in gas chromatographic characterization of mycobacteria: differentiation between Mycobacterium avium-intracellulare and Mycobacterium gastri.

    Science.gov (United States)

    Larsson, L

    1983-08-01

    Mycobacterium avium-intracellulare and M.gastri were analyzed with capillary gas chromatography after each strain had been subjected to acidic methanolysis or to alkaline saponification followed by methylation. Prominent peaks of myristic, palmitoleic, palmitic, oleic, stearic and tuberculostearic acids were found in the chromatograms of both species, whereas 2-octadecanol and 2-eicosanol were detected only in M. avium-intracellulare. In initial runs, both of the derivatization principles yielded virtually identical chromatograms for a given strain. After repeated injections of extracts from alkaline saponification, however, the alcohol peaks showed pronounced tailing and finally almost disappeared from the chromatograms. This disadvantage, which was not observed when only acid methanolysis was used, could be overcome with trifluoroacetylation. Restored peak shape of the underivatized alcohols could be achieved by washing the cross-linked stationary phase in the capillary tubing with organic solvents. The study demonstrated the importance of conditions which enable separation of 2-octadecanol and 2-eicosanol when gas chromatography is used for species identification of mycobacteria.

  3. Evaluation of the retention pattern on ionic liquid columns for gas chromatographic analyses of fatty acid methyl esters.

    Science.gov (United States)

    Lin, Chen-Chen; Wasta, Ziar; Mjøs, Svein A

    2014-07-11

    Fatty acid methyl esters from marine sources were analyzed by gas chromatography-mass spectrometry on three ionic liquid columns, SLB-IL61, SLB-IL82 and SLB-IL100 (Supelco). Retention indices (equivalent chain lengths) are reported for more than 100 compounds and the overlap patterns are evaluated from these data. The influence of chromatographic conditions on the retention indices of unsaturated fatty acid methyl esters is also evaluated. Compared to typical alternative phases the retention patterns on all three columns are highly dependent on the conditions. The SLB-IL61 phase had overlaps between nutritionally important fatty acids that could not be resolved by changing the chromatographic conditions. This column is therefore regarded as unsuitable for clinical and nutritional studies of the fatty acid composition, but similar overlaps may be avoided on IL82 and IL100. On all three columns double bonds close to the carboxyl group in the analytes contribute with limited retention, which makes it challenging to predict the retention of polyunsaturated fatty acid methyl esters.

  4. Gas Chromatography Analysis of Resin and Fatty Acids from Laboratory Generated Bleach Plant Effluents

    Institute of Scientific and Technical Information of China (English)

    Chhaya Sharma; S. Mohanty; S. Kumar; N.J. Rao

    2007-01-01

    Laboratory generated spent bleached liquor from the chlorination, caustic extraction stage of mixed wood kraft pulp processing has been analyzed both qualitatively and quantitatively for various resin & fatty acids by using GC. A number of resin acids,saturated and unsaturated fatty acids, chloro fatty and resin acid have been detected and their concentrations are estimated. The results are compared with results on different agriculture residue/hardwood pulps, which were reported earlier. The concentrations of various compounds detected have also been compared with their reported LC50 values.

  5. Gas release-based prescreening combined with reversed-phase HPLC quantitation for efficient selection of high-γ-aminobutyric acid (GABA)-producing lactic acid bacteria.

    Science.gov (United States)

    Wu, Qinglong; Shah, Nagendra P

    2015-02-01

    High γ-aminobutyric acid (GABA)-producing lactobacilli are promising for the manufacture of GABA-rich foods and to synthesize GRAS (generally recognized as safe)-grade GABA. However, common chromatography-based screening is time-consuming and inefficient. In the present study, Korean kimchi was used as a model of lactic acid-based fermented foods, and a gas release-based prescreening of potential GABA producers was developed. The ability to produce GABA by potential GABA producers in de Man, Rogosa, and Sharpe medium supplemented with or without monosodium glutamate was further determined by HPLC. Based on the results, 9 isolates were regarded as high GABA producers, and were further genetically identified as Lactobacillus brevis based on the sequences of 16S rRNA gene. Gas release-based prescreening combined with reversed-phase HPLC confirmation was an efficient and cost-effective method to identify high-GABA-producing LAB, which could be good candidates for probiotics. The GABA that is naturally produced by these high-GABA-producing LAB could be used as a food additive.

  6. Sulfur Recovery from Acid Gas Using the Claus Process and High Temperature Air Combustion (HiTAC Technology

    Directory of Open Access Journals (Sweden)

    Mohamed Sassi

    2008-01-01

    Full Text Available Sulfur-bearing compounds are very detrimental to the environment and to industrial process equipment. They are often obtained or formed as a by-product of separation and thermal processing of fuels containing sulfur, such as coal, crude oil and natural gas. The two sulfur compounds, which need special attention, are: hydrogen sulfide (H2S and sulfur dioxide (SO2. H2S is a highly corrosive gas with a foul smell. SO2 is a toxic gas responsible for acid rain formation and equipment corrosion. Various methods of reducing pollutants containing sulfur are described in this paper, with a focus on the modified Claus process, enhanced by the use of High Temperature Air Combustion (HiTAC technology in the Claus furnace. The Claus process has been known and used in the industry for over 100 years. It involves thermal oxidation of hydrogen sulfide and its reaction with sulfur dioxide to form sulfur and water vapor. This process is equilibrium-limited and usually achieves efficiencies in the range of 94-97%, which have been regarded as acceptable in the past years. Nowadays strict air pollution regulations regarding hydrogen sulfide and sulfur dioxide emissions call for nearly 100% efficiency, which can only be achieved with process modifications. High temperature air combustion technology or otherwise called flameless (or colorless combustion is proposed here for application in Claus furnaces, especially those employing lean acid gas streams, which cannot be burned without the use of auxiliary fuel or oxygen enrichment under standard conditions. With the use of HiTAC it has been shown, however, that fuel-lean, Low Calorific Value (LCV fuels can be burned with very uniform thermal fields without the need for fuel enrichment or oxygen addition. The uniform temperature distribution favors clean and efficient burning with an additional advantage of significant reduction of NOx, CO and hydrocarbon emission.

  7. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Liu Yang

    2015-06-01

    Full Text Available Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant and 2-CEES (a blister agent simulant were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  8. Research on the interaction of hydrogen-bond acidic polymer sensitive sensor materials with chemical warfare agents simulants by inverse gas chromatography.

    Science.gov (United States)

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-06-02

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  9. Thermodynamic modeling of acidic gas solubility in aqueous solutions of MEA, MDEA and MEA-MDEA blends

    DEFF Research Database (Denmark)

    Vrachnos, Ath.; Kontogeorgis, Georgios; Voutsas, EC

    2006-01-01

    The thermodynamic framework that was developed in a previous work [Vrachnos et al. Ind. Eng. Chem. Res. 2004, 43, 2798] for the description of chemical and vapor-liquid equilibria of carbon dioxide, hydrogen sulfide, and their mixtures in aqueous methyldiethanolamine (MDEA) solutions is revised...... and extended in this study to the absorption of carbon dioxide into aqueous monoethanolamine (MEA) solutions and aqueous MDEA-MEA blends. The results of the model are compared with experimental data taken from the literature. Very satisfactory predictions of acidic gas vapor-liquid equilibrium over MDEA, MEA...

  10. Exploring the Ideal Gas Law through a Quantitative Gasometric Analysis of Nitrogen Produced by the Reaction of Sodium Nitrite with Sulfamic Acid

    Science.gov (United States)

    Yu, Anne

    2010-01-01

    The gasometric analysis of nitrogen produced in a reaction between sodium nitrite, NaNO[superscript 2], and sulfamic acid, H(NH[superscript 2])SO[superscript 3], provides an alternative to more common general chemistry experiments used to study the ideal gas law, such as the experiment in which magnesium is reacted with hydrochloric acid. This…

  11. Gas chromatography-mass spectrometry analysis of fatty acid profiles of Antarctic and non-Antarctic yeasts.

    Science.gov (United States)

    Bhuiyan, Mohammad; Tucker, David; Watson, Kenneth

    2014-08-01

    The fatty acid profiles of Antarctic (n = 7) and non-Antarctic yeasts (n = 7) grown at different temperatures were analysed by gas chromatography-mass spectrometry. The Antarctic yeasts were enriched in oleic 18:1 (20-60 %), linoleic 18:2 (20-50 %) and linolenic 18:3 (5-40 %) acids with lesser amounts of palmitic 16:0 (Antarctic yeasts (n = 4) were enriched in 18:1 (20-55 %, with R. mucilaginosa at 75-80 %) and 18:2 (10-40 %) with lesser amounts of 16:0 (Antarctic yeasts (enriched in 18:1 and 18:2) and the third to the Antarctic yeasts (enriched in 18:2 and 18:3).

  12. Hazard and Prevention of Gas Gap in Hearth Wall of Blast Furnace%高炉炉缸气隙的危害及防治

    Institute of Scientific and Technical Information of China (English)

    邹忠平; 郭宪臻

    2012-01-01

    从炉缸问题调查着手,通过大量理论计算指出了炉缸气隙的危害,并结合现场调查、施工和生产实践,分析了炉缸产生气隙的各种因素,最终提出了从设计、施工到高炉操作的这些炉缸长寿链上各关键环节系统防止炉缸气隙的有效措施,为高炉炉缸实现无气隙化操作、实现炉缸长寿提供了全面的解决方案。研究指出夹壳式冷却方式、热水烘炉、防止炉缸漏水是减小炉缸气隙最有效的措施。%Gas gap was the biggest threat to BF hearth long campaign life. Through academic calculations and field investigations, the influencing factors to cause gas gap in hearth area was analyzed. As the results, the effective measures involving design, construction and operation were proposed to avoid gas gap for long campaign life of BF hearth, and the solutions were provided to achieve non-gas gap operation and long hearth life. Jacket cooling, using hot water during furnace drying process and leak prevention were found to be the most effective measures of gas gap prevention.

  13. Effect of thermal annealing on a novel polyamide–imide polymer membrane for aggressive acid gas separations

    KAUST Repository

    Vaughn, Justin T.

    2012-05-01

    A fluorinated, 6FDA based polyamide-imide is investigated for the purification of CH 4 from CO 2 and H 2S containing gas streams. Dense polymer films were thermally annealed and showed that increased annealing temperatures at constant annealing time caused transport behavior that does not resemble physical aging. Free volume increased after annealing at 200°C for 24h relative to annealing at 150°C for the same time. CO 2 and CH 4 permeabilities and diffusivities did not decrease as a result of the higher annealing temperature, and in fact, were shown to increase slightly. A change to the intrinsic microstructure that cannot be described by simple, densification based physical aging is hypothesized to be the reason for this trend. Furthermore, annealing increased CO 2 induced plasticization resistance and a temperature of 200°C was shown to have the greatest effect on plasticization suppression. Annealing at 200°C for 24h suppressed pure gas CO 2 plasticization up to 450psia. Fluorescence spectroscopy revealed increased intramolecular charge transfer, which is presumably due to increased electron conjugation over the N-phenyl bond. Additionally, intermolecular charge transfer increased with thermal annealing, as inferred from fluorescence intensity measurements and XRD patterns. 50/50 CO 2/CH 4 mixed gas permeation measurements reveal stable separation performance up to 1000psia. Ternary mixed gas feeds containing toluene/CO 2/CH 4 and H 2S/CO 2/CH 4 show antiplasticization, but more importantly, selectivity losses due to plasticization did not occur up to 900psia of total feed pressure. These results show that the polyamide-imide family represents a promising class of separation materials for aggressive acid gas purifications. © 2012 Elsevier B.V.

  14. Characterization of Fatty Acid Profile of Argan Oil and Other Edible Vegetable Oils by Gas Chromatography and Discriminant Analysis

    Directory of Open Access Journals (Sweden)

    Ascensión Rueda

    2014-01-01

    Full Text Available Virgin argan oil is an emergent oil that is being introduced into specialized international markets as a healthy and luxury food. In order to compare the fatty acid composition of argan oil with that of the eleven other vegetable edible oils, a combination of gas chromatography as analytical technique and multivariate discriminant analysis was applied. This analysis takes into account the conjoint effect of all the variables analyzed in the discrimination between oils and also shows the contribution of each variable to oils characterization. The model correctly classified 100% oil samples. According to the fatty acid composition, argan oil showed closest similarity firstly with sesame oil and secondly with high oleic sunflower oil. Olive oil was close to avocado oil and almond oil, followed by argan oil. Thus, similarities and differences between vegetable oils based on their fatty acid profile were established by the application of multivariate discriminant analysis. This method was proven to be a useful tool to study the relationships between oils according to the fat composition and to determine the importance of the fatty acid variables on the oils classification.

  15. CO2 Capture from Flue gas using Amino acid salt solutions

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai

    to storage. Typical solvents for the process are based on aqueous solutions of alkanolamines, such as mono-ethanolamine (MEA), but their use implies economic disadvantages and environmental complications. Amino acid salt solutions have emerged as an alternative to the alkanolamines, partlybecause....../or amino acid salt concentrations. The formation of solids poses challenges, but it also holds the promise for improving the efficiency of the capture process. This project focuses on phase equilibrium experiments of five systems CO2 + amino acid salt + H2O, at conditions relevant for the CO2 capture...... process. Also, attention is given to the chemical compositions of the precipitations, which forms as a result of CO2 absorption into the five amino acid salt solutions. Phase equilibrium data are needed to develop safe and economically viable capture processes. Two different experimental apparatuses were...

  16. Kinetics of gas phase formic acid decomposition on platinum single crystal and polycrystalline surfaces

    Science.gov (United States)

    Detwiler, Michael D.; Milligan, Cory A.; Zemlyanov, Dmitry Y.; Delgass, W. Nicholas; Ribeiro, Fabio H.

    2016-06-01

    Formic acid dehydrogenation turnover rates (TORs) were measured on Pt(111), Pt(100), and polycrystalline Pt foil surfaces at a total pressure of 800 Torr between 413 and 513 K in a batch reactor connected to an ultra-high vacuum (UHV) system. The TORs, apparent activation energies, and reaction orders are not sensitive to the structure of the Pt surface, within the precision of the measurements. CO introduced into the batch reactor depressed the formic acid dehydrogenation TOR and increased the reaction's apparent activation energies on Pt(111) and Pt(100), consistent with behavior predicted by the Temkin equation. Two reaction mechanisms were explored which explain the formic acid decomposition mechanism on Pt, both of which include dissociative adsorption of formic acid, rate limiting formate decomposition, and quasi-equilibrated hydrogen recombination and CO adsorption. No evidence was found that catalytic supports used in previous studies altered the reaction kinetics or mechanism.

  17. NASA Hazard Analysis Process

    Science.gov (United States)

    Deckert, George

    2010-01-01

    This viewgraph presentation reviews The NASA Hazard Analysis process. The contents include: 1) Significant Incidents and Close Calls in Human Spaceflight; 2) Subsystem Safety Engineering Through the Project Life Cycle; 3) The Risk Informed Design Process; 4) Types of NASA Hazard Analysis; 5) Preliminary Hazard Analysis (PHA); 6) Hazard Analysis Process; 7) Identify Hazardous Conditions; 8) Consider All Interfaces; 9) Work a Preliminary Hazard List; 10) NASA Generic Hazards List; and 11) Final Thoughts

  18. The Tiptop coal-mine fire, Kentucky: Preliminary investigation of the measurement of mercury and other hazardous gases from coal-fire gas vents

    Science.gov (United States)

    Hower, J.C.; Henke, K.; O'Keefe, J. M. K.; Engle, M.A.; Blake, D.R.; Stracher, G.B.

    2009-01-01

    The Tiptop underground coal-mine fire in the Skyline coalbed of the Middle Pennsylvanian Breathitt Formation was investigated in rural northern Breathitt County, Kentucky, in May 2008 and January 2009, for the purpose of determining the concentrations of carbon dioxide (CO2), carbon monoxide (CO), and mercury (Hg) in the vent and for measuring gas-vent temperatures. At the time of our visits, concentrations of CO2 peaked at 2.0% and > 6.0% (v/v) and CO at 600 ppm and > 700 ppm during field analysis in May 2008 and January 2009, respectively. For comparison, these concentrations exceed the U.S. Occupational Safety & Health Administration (OSHA) eight-hour safe exposure limits (0.5% CO2 and 50 ppm CO), although the site is not currently mined. Mercury, as Hg0, in excess of 500 and 2100 ??g/m3, in May and January, respectively, in the field, also exceeded the OSHA eight-hour exposure limit (50 ??g/m3). Carbonyl sulfide, dimethyl sulfide, carbon disulfide, and a suite of organic compounds were determined at two vents for the first sampling event. All gases are diluted by air as they exit and migrate away from a gas vent, but temperature inversions and other meteorological conditions could lead to unhealthy concentrations in the nearby towns. Variation in gas temperatures, nearly 300 ??C during the January visit to the fire versus vent gases. ?? 2009 Elsevier B.V.

  19. Wheat dextrin, psyllium, and inulin produce distinct fermentation patterns, gas volumes, and short-chain fatty acid profiles in vitro.

    Science.gov (United States)

    Timm, Derek A; Stewart, Maria L; Hospattankar, Ashok; Slavin, Joanne L

    2010-08-01

    Dietary fiber fermentation decreases luminal pH by the production of short-chain fatty acids (SCFAs). Additional proposed physiological benefits of fiber fermentation include decreased growth of pathogenic bacteria, increased mineral absorption, and serving as an energy source for the colon epithelium. This study examined three common fiber supplements--wheat dextrin (WD) (Benefiber, Novartis Consumer Health Inc., Parsippany, NJ, USA), psyllium (PS) (Metamucil, Procter & Gamble, Cincinnati, OH, USA), and inulin (Fiber Sure, Procter & Gamble)--for pH, SCFAs, and gas production. An established in vitro fermentation model was used to simulate colonic fermentation at 0, 4, 8, 12, and 24 hours. At 24 hours, WD and inulin significantly decreased pH compared to PS. Inulin produced significantly more hydrogen and total gas. All treatments produced similar total SCFA concentrations at 24 hours; however, the rate of production was different. PS had a declining rate of SCFA production from 12 to 24 hours, whereas WD and inulin had a higher rate during that period. Fast-fermenting substrates may not provide as much SCFAs to the distal colon as slow-fermenting substrates. Differences in fermentation rate, gas production, and SCFA production observed for WD, PS, and inulin may affect their gastrointestinal tolerance and require further study.

  20. Carbohydrates blended with polydextrose lower gas production and short-chain fatty acid production in an in vitro system.

    Science.gov (United States)

    Vester Boler, Brittany M; Hernot, David C; Boileau, Thomas W; Bauer, Laura L; Middelbos, Ingmar S; Murphy, Michael R; Swanson, Kelly S; Fahey, George C

    2009-09-01

    Maximizing health benefits of prebiotics, while limiting negative side effects, is of importance to the food industry. This study examined several oligosaccharides and their blends in an in vitro fermentation model. Substrates included medium- and long-chain fructooligosaccharides (FOS), oligofructose-enriched inulin, galactooligosaccharide, polydextrose (POL), and 50:50 substrate blends. Substrates and blends were fermented in vitro using human fecal inoculum, and fermentation characteristics were quantified at 0, 4, 8, and 12 hours. We hypothesized that mixtures of short- and long-chain oligosaccharides would generate less gas than do short-chain oligosaccharides and modulate gut microflora to a greater extent than do long-chain oligosaccharides. Carbohydrates blended with POL had decreased (P inulin products led to less (P inulin after 12 hours of in vitro fermentation was lower (P < .05) when mixed with POL. Mixing the pure carbohydrates with galactooligosaccharide increased (P < .05) bifidobacteria counts measured after 12 hours of in vitro fermentation, except when mixed with medium-chain FOS. In general, when mixed with POL, all carbohydrates had lower gas production, gas production rates, butyrate and total short-chain fatty acid production, and bifidobacteria counts than when fermented alone for 12 hours.

  1. Dispersive Surface Energy and Acid-Base Parameters of Tosylate Functionalized Poly(ethylene glycol via Inverse Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Feyza Sesigur

    2014-01-01

    Full Text Available An inverse gas chromatographic (IGC study of the sorption properties of poly(ethylene glycol modified with tosylate (PEG-TOS was presented. PEG-TOS was synthesized via the tosylation of the corresponding poly(ethylene glycol (PEG with p-toluenesulfonyl chloride in the basic medium. The synthesized PEG-Tos was characterized by FTIR-ATR and 1HNMR techniques. The retention diagrams of n-hexane, n-heptane, n-octane, n-nonane, n-decane, dichloromethane, chloroform, acetone, tetrahydrofuran, ethyl acetate, and ethanol on the PEG and PEG-Tos were plotted at temperatures in K between 303 and 373 by inverse gas chromatography technique. The dispersive component of the surface-free energy, γSD, of studied adsorbent surface was estimated using retention times of different nonpolar organics in the infinite dilution region. Thermodynamic parameters of adsorption (free energy, ΔGAS, enthalpy, ΔHAS, and entropy, ΔSAS, dispersive components of the surface energies, γSD, and the acid, KA, and base, KD, constants for the PEG and PEG-Tos were calculated and the results were discussed.

  2. 天然气制甲醇关键过程火灾爆炸危险性分析%Fire and explosion hazard analysis of the principal process in methanol production from natural gas

    Institute of Scientific and Technical Information of China (English)

    尹彩虹; 孙金华

    2012-01-01

    In this paper we are trying to make a detailed description of the fire and explosion risks prone to take place in the methanol production. For this purpose, we have mainly engaged in the analysis of the methanol production, which is an important organic chemical of wide applications in chemical industry. In our paper, we have also made a brief review of the research status quo of the production and remaining problems involving the methanol production process with the natural gas as its raw material. While analyzing the explosion hazards of methanol production process, we have resorted to the DOW chemical explosion index method, which involves two major hazard process units. The two major hazard process units are known as the natural gas conversion and the heat recovery process unit and the methanol synthesis process unit. In proceeding with our analysis, we have applied the fault tree analysis method. In doing the fault tree analysis, we need to analyze the system safety of the two key process units of methanol production, that is, the hazard types of fire and explosion of the methanol production process which include the leakage type and reaction out-of-control type. In order to make the successful analysis, we have to first of all work out the fault tree based on the accidents and the factors which may account for the fire or explosion accidents. And, here we have established two minimal cut sets by using Boolean algebra reduction method with the sequence of the structure importance of each factor involved. And, next, we have to determine the way how the fire and explosion accidents occur and the order of the degree of difficulty in which the two process units might have experienced, respectively. In terms of the natural gas conversion and heat recovery processes unit, we can have 20 pathways that are likely to cause the fire and explosion accidents. And, in terms of the debugging mistakes of process parameters and illegal operation, we have worked out 23

  3. 离子色谱法测定工业废气中的甲酸、乙酸和丙酸%Industrial waste gas by ion chromatography determination of formic acid, acetic acid and propionic acid

    Institute of Scientific and Technical Information of China (English)

    吴红星

    2013-01-01

    建立了用离子色谱法测定工业废气中甲酸、乙酸和丙酸的新方法,常规无机阴离子对本方法的测定没有干扰。本方法分析速度快,所需样品量少,且无需要复杂的前处理,简便、灵敏、可靠。%established by ion chromatography determination of formic acid , acetic acid and propionic acid in industrial waste gas , a new method for the determination of inorganic anions , the conventional method without interference .This method is fast , small quantity of sam-ple, and no need of complicated pretreatment , simple, sensitive, reliable.

  4. Experimental study and phase equilibrium modeling of systems containing acid gas and glycol

    DEFF Research Database (Denmark)

    Afzal, Waheed; Breil, Martin P.; Tsivintzelis, Ioannis;

    2012-01-01

    In this work, we study phase equilibria of systems containing acid gases and glycols. The acid gases include carbonyl sulfide (COS), hydrogen sulfide (H2S), and carbon dioxide (CO2) while glycols include monoethylene glycol (MEG), diethylene glycol (DEG), and triethylene glycol (TEG). A brief...... literature survey on the solubility of the acid gases and hydrocarbons in glycols is presented. New experimental solubility data mainly for COS and some limited data for H2S in glycols from 276 to 333K and at elevated pressures are reported. Experimental measurements have been carried out using the “static......-synthetic” method. The reliability and repeatability of the experimental work are demonstrated. The experimental solubility data for COS and glycols, from this work, and those for H2S and CO2 from the literature are modeled using the cubic-plus-association (CPA) equation of state (EoS). CPA parameters for pure...

  5. A new online exhaust gas monitoring system in hydrochloric acid regeneration of cold rolling mills.

    Science.gov (United States)

    Tuo, Long; Zheng, Xiang; Chen, Xiong

    2015-07-07

    Measuring the content of hydrogen chloride (HCl) in exhaust gas used to take time and energy. In this paper, we introduce a new online monitoring system which can output real-time data to the monitoring center. The system samples and cools exhaust gas, and after a series of processing, it will be analyzed by a specific instrument. The core part of this system is remote terminal unit (RTU) which is designed on Cortex-A8 embedded architecture. RTU runs a scaled-down version of Linux which is a good choice of OS for embedded applications. It controls the whole processes, does data acquisition and data analysis, and communicates with monitoring center through Ethernet. In addition, through a software developed for windows, the monitoring process can be remotely controlled. The new system is quite beneficial for steel industry to do environment monitoring.

  6. Influence of different storage times and temperatures on blood gas and acid-base balance in ovine venous blood

    Directory of Open Access Journals (Sweden)

    H.A. Hussein

    2013-01-01

    Full Text Available The present study was designed to investigate the effects of storage temperature and time on blood gas and acid-base balance of ovine venous blood. Ten clinically healthy sheep were used in this study. A total number of 30 blood samples, were divided into three different groups, and were stored in a refrigerator adjusted to +4 ºC (Group I, n = 10, at RT of about 22-25 ºC (Group II, n = 10 and in an incubator adjusted to 37 ºC (Group III, n = 10 for up to 48 h. Blood samples were analysed for blood gas and acid-base indices at 0, 1, 2, 3, 4, 5, 6, 12, 24 and 48 h of storage. In comparison to the baseline value (0, there were significant decreases of blood pH of samples stored at RT and in the incubator after 1 h (p<0.05, the pH value of refrigerated blood samples exhibited insignificant changes during the study (p<0.05. Mean values of pCO2 showed a significant increase in Group I and Group III after 1 h then a progressive decrease after 12 h in all Groups. Mean pO2 values were significantly higher for Group I after 2 h and for Groups II and III after 1 h (p<0.05. In general, base excess decreased significantly for all the groups during the study especially in Groups II and III. In comparison with baseline values, in all groups, bicarbonate (HCO3 increased between 1 h and 6 h (p<0.05, and later decreased at the end of the study (p<0.05. In conclusion, status of acid-base indices of the samples stored at refrigerator and RT were found within normal reference range and it may be of clinical diagnostic use for up to 6 h.

  7. Potential hazards of air pollutant emissions from unconventional oil and natural gas operations on the respiratory health of children and infants.

    Science.gov (United States)

    Webb, Ellen; Hays, Jake; Dyrszka, Larysa; Rodriguez, Brian; Cox, Caroline; Huffling, Katie; Bushkin-Bedient, Sheila

    2016-06-01

    Research on air pollutant emissions associated with unconventional oil and gas (UOG) development has grown significantly in recent years. Empirical investigations have focused on the identification and measurement of oil and gas air pollutants [e.g. volatile organic compounds (VOCs), particulate matter (PM), methane] and the influence of UOG on local and regional ambient air quality (e.g. tropospheric ozone). While more studies to better characterize spatial and temporal trends in exposure among children and newborns near UOG sites are needed, existing research suggests that exposure to air pollutants emitted during lifecycle operations can potentially lead to adverse respiratory outcomes in this population. Children are known to be at a greater risk from exposure to air pollutants, which can impair lung function and neurodevelopment, or exacerbate existing conditions, such as asthma, because the respiratory system is particularly vulnerable during development in-utero, the postnatal period, and early childhood. In this article, we review the literature relevant to respiratory risks of UOG on infants and children. Existing epidemiology studies document the impact of air pollutant exposure on children in other contexts and suggest impacts near UOG. Research is sparse on long-term health risks associated with frequent acute exposures - especially in children - hence our interpretation of these findings may be conservative. Many data gaps remain, but existing data support precautionary measures to protect the health of infants and children.

  8. Analysis of fecal bile acids and neutral steroids using gas-liquid chromatography

    NARCIS (Netherlands)

    Srikumar, T.S.; Wezendonk, B.; Dokkum, W. van

    1998-01-01

    In the present pilot study, for investigating the physiological effects of different types of nondigestible oligosaccharides, we have validated the application of methodologies for the analysis of bile acids and neutral steroids in feces of human subjects. The accuracy of the extraction and chromato

  9. A validated method for gas chromatographic analysis of gamma-aminobutyric acid in tall fescue herbage

    Science.gov (United States)

    Gamma-Aminobutyric acid (GABA) is an inhibitory neurotransmitter in animals that is also found in plants and has been associated with plant responses to stress. A simple and relatively rapid method of GABA separation and quantification was developed from a commercially available kit for serum amino...

  10. Surface properties of calcium and magnesium oxide nanopowders grafted with unsaturated carboxylic acids studied with inverse gas chromatography.

    Science.gov (United States)

    Maciejewska, Magdalena; Krzywania-Kaliszewska, Alicja; Zaborski, Marian

    2012-09-28

    Inverse gas chromatography (IGC) was applied at infinite dilution to evaluate the surface properties of calcium and magnesium oxide nanoparticles and the effect of surface grafted unsaturated carboxylic acid on the nanopowder donor-acceptor characteristics. The dispersive components (γ(s)(D)) of the free energy of the nanopowders were determined by Gray's method, whereas their tendency to undergo specific interactions was estimated based on the electron donor-acceptor approach presented by Papirer. The calcium and magnesium oxide nanoparticles exhibited high surface energies (79 mJ/m² and 74 mJ/m², respectively). Modification of nanopowders with unsaturated carboxylic acids decreased their specific adsorption energy. The lowest value of γ(s)(D) was determined for nanopowders grafted with undecylenic acid, approximately 55 mJ/m². The specific interactions were characterised by the molar free energy (ΔG(A)(SP)) and molar enthalpy (ΔH(A)(SP)) of adsorption as well as the donor and acceptor interaction parameters (K(A), K(D)).

  11. Comparison of two gas-liquid chromatograph columns for the analysis of fatty acids in ruminant meat.

    Science.gov (United States)

    Alves, Susana P; Bessa, Rui J B

    2009-06-26

    Two gas-liquid chromatograph capillary columns for the analysis of fatty acids (FA) in ruminant fat are compared. Those columns are the CP-Sil 88 of 100 m long with a highly polar stationary phase and the Omegawax 250 of 30 m long with a stationary phase of intermediate polarity. Fatty acid methyl ester (FAME) patterns of branched-chain, cis and trans octadecenoate isomers, as well as conjugated and non-conjugated 18:2 and 18:3 isomers are fairly different between columns, even though most of the FAME could be separated on either column. However, the CP-Sil 88 showed better resolution of 18:1 isomers than Omegawax 250. The analysis of 96 samples of ruminant meat fat in both chromatographic systems showed that averages obtained for total FA content and for most of the individual FA did not differ between columns. Moreover, regression analysis of Omegawax and CP-Sil 88 data is highly correlated. Quantitative differences between chromatographic systems were detected for samples containing more than 66 mg fatty acids per gram of muscle dry matter.

  12. An Experimental and Computational Investigation into the Gas-Phase Acidities of Tyrosine and Phenylalanine: Three Structures for Deprotonated Tyrosine

    Energy Technology Data Exchange (ETDEWEB)

    Bokatzian, Samantha S.; Stover, Michele L.; Plummer, Chelsea E.; Dixon, David A.; Cassady, Carolyn J.

    2014-11-06

    Using mass spectrometry and correlated molecular orbital theory, three deprotonated structures were revealed for the amino acid tyrosine. The structures were distinguished experimentally by ion/molecule reactions involving proton transfer and trimethylsilyl azide. Gas-phase acidities from proton transfer reactions and from G3(MP2) calculations generally agree well. The lowest energy structure, which was only observed experimentally using electrospray ionization from aprotic solvents, is deprotonated at the carboxylic acid group and is predicted to be highly folded. A second unfolded carboxylate structure is several kcal/mol higher in energy and primarily forms from protic solvents. Protic solvents also yield a structure deprotonated at the phenolic side chain, which experiments find to be intermediate in energy to the two carboxylate forms. G3(MP2) calculations indicate that the three structures differ in energy by only 2.5 kcal/mol, yet they are readily distinguished experimentally. Structural abundance ratios are dependent upon experimental conditions, including the solvent and accumulation time of ions in a hexapole. Under some conditions, carboxylate ions may convert to phenolate ions. For phenylalanine, which lacks a phenolic group, only one deprotonated structure was observed experimentally when electrosprayed from protic solvent. This agrees with G3(MP2) calculations that find the folded and unfolded carboxylate forms to differ by 0.3 kcal/mol.

  13. Profiling fatty acids in vegetable oils by reactive pyrolysis-gas chromatography with dimethyl carbonate and titanium silicate.

    Science.gov (United States)

    Fabbri, Daniele; Baravelli, Valentina; Chiavari, Giuseppe; Prati, Silvia

    2005-12-30

    A novel methodology in on-line pyrolysis-gas chromatography (Py-GC) for the fast analysis of fatty acids in vegetable oils with minimal sample treatment and the use of non-toxic reagents is described. Pyrolysis at 500 degrees C for 10 s of sub-microgram quantity of vegetable oil dissolved in dimethyl carbonate (DMC) and in the presence of nanopowder titanium silicon oxide resulted in the production of fatty acid methyl esters (FAMEs) as unique products. Pyrolysis performed by means of a resistively heated filament pyrolyser interfaced to a GC-MS apparatus enabled the direct analysis of evolved FAMEs. The DMC/Py-GC-MS analysis was tested on soybean, coconut, linseed, walnut and olive oil and the results compared to the classical BF(3)-methanol as reference methodology. The DMC method exhibited a lower precision and was biased towards lower levels of polyunsaturated fatty acids (PUFA) in comparison to the BF(3)-methanol method, but was more advantageous in terms of reduced sample treatment, waste generation and risk factors of employed chemicals.

  14. Mineral concentrations of forage legumes and grasses grown in acidic soil amended with flue gas desulfurization products

    Energy Technology Data Exchange (ETDEWEB)

    Clark, R.B.; Baligar, V.C. [USDA ARS, Beltsville, MD (USA). Beltsville Agricultural Research Center West

    2003-07-01

    Considerable quantities of flue gas desulfurization products (FGDs) are generated when coal is burned for production of electricity, and these products have the potential to be reused rather than discarded. Use of FGDs as soil amendments could be important in overall management of these products, especially on acidic soils. Glasshouse studies were conducted to determine shoot concentrations of calcium (Ca), sulfur (S), potassium (K), magnesium (Mg), phosphorus (P), boron (B), zinc (Zn), copper (Cu), manganese (Mn), iron (Fe), aluminum (Al), sodium (Na), molybdenum (Mo), nickel (Ni), cadmium (Cd), chromium (Cr), and lead (Pb) in alfalfa (Medicago sativa), white clover (Trifolium repens), orchardgrass (Dacrylis glomerata), tall fescue (Festuca arundinacea), switchgrass (Panicum virgatum), and eastern gamagrass (Tripsacum dactyloides) grown in acidic (pH 4) soil (Typic Hapludult) amended with various levels of three FGDs and the control compounds CaCO{sub 3}, CaSO{sub 3}, and CaSO{sub 4}. Shoot concentrations of Ca, S, Mg, and B generally increased as levels of soil applied FGD increased. Concentrations of Mn, Fe, Zn, Cu were lower in shoots, especially when soil pH was high ({gt}7). Shoot concentrations of the trace elements Mo, Ni, Cd, Cr, and Pb were not above those reported as normal for foliage. Overall concentrations of most minerals remained near normal for shoots when plants were grown in FGD amended acidic soil.

  15. An experimental and computational investigation into the gas-phase acidities of tyrosine and phenylalanine: three structures for deprotonated tyrosine.

    Science.gov (United States)

    Bokatzian, Samantha S; Stover, Michele L; Plummer, Chelsea E; Dixon, David A; Cassady, Carolyn J

    2014-11-01

    Using mass spectrometry and correlated molecular orbital theory, three deprotonated structures were revealed for the amino acid tyrosine. The structures were distinguished experimentally by ion/molecule reactions involving proton transfer and trimethylsilyl azide. Gas-phase acidities from proton transfer reactions and from G3(MP2) calculations generally agree well. The lowest energy structure, which was only observed experimentally using electrospray ionization from aprotic solvents, is deprotonated at the carboxylic acid group and is predicted to be highly folded. A second unfolded carboxylate structure is several kcal/mol higher in energy and primarily forms from protic solvents. Protic solvents also yield a structure deprotonated at the phenolic side chain, which experiments find to be intermediate in energy to the two carboxylate forms. G3(MP2) calculations indicate that the three structures differ in energy by only 2.5 kcal/mol, yet they are readily distinguished experimentally. Structural abundance ratios are dependent upon experimental conditions, including the solvent and accumulation time of ions in a hexapole. Under some conditions, carboxylate ions may convert to phenolate ions. For phenylalanine, which lacks a phenolic group, only one deprotonated structure was observed experimentally when electrosprayed from protic solvent. This agrees with G3(MP2) calculations that find the folded and unfolded carboxylate forms to differ by 0.3 kcal/mol.

  16. delta 13C analyses of vegetable oil fatty acid components, determined by gas chromatography--combustion--isotope ratio mass spectrometry, after saponification or regiospecific hydrolysis.

    Science.gov (United States)

    Woodbury, S E; Evershed, R P; Rossell, J B

    1998-05-01

    The delta 13C values of the major fatty acids of several different commercially important vegetable oils were measured by gas chromatography--combustion--isotope ratio mass spectrometry. The delta 13C values obtained were found to fall into two distinct groups, representing the C3 and C4 plants classes from which the oils were derived. The delta 13C values of the oils were measured by continuous flow elemental isotope ratio mass spectrometry and were found to be similar to their fatty acids, with slight differences between individual fatty acids. Investigations were then made into the influence on the delta 13C values of fatty acids of the position occupied on the glycerol backbone. Pancreatic lipase was employed to selectively hydrolyse fatty acids from the 1- and 3-positions with the progress of the reaction being followed by high-temperature gas chromatography in order to determine the optimum incubation time. The 2-monoacylglycerols were then isolated by thin-layer chromatography and fatty acid methyl esters prepared. The delta 13C values obtained indicate that fatty acids from any position on the glycerol backbone are isotopically identical. Thus, whilst quantification of fatty acid composition at the 2-position and measurement of delta 13C values of oils and their major fatty acids are useful criteria in edible oil purity assessment, measurement of delta 13C values of fatty acids from the 2-position does not assist with oil purity assignments.

  17. Metabolism, gas exchange, and acid-base balance of giant salamanders.

    Science.gov (United States)

    Ultsch, Gordon R

    2012-08-01

    The giant salamanders are aquatic and paedomorphic urodeles including the genera Andrias and Cryptobranchus (Cryptobranchidae), Amphiuma (Amphiumidae), Siren (Sirenidae), and Necturus (Proteidae, of which only N. maculosus is considered 'a giant'). Species in the genera Cryptobranchus and Necturus are considered aquatic salamanders well adapted for breathing water, poorly adapted for breathing air, and with limited abilities to compensate acid-base disturbances. As such, they are water-breathing animals with a somewhat fish-like respiratory and acid-base physiology, whose habitat selection is limited to waters that do not typically become hypoxic or hypercarbic (although this assertion has been questioned for N. maculosus). Siren and Amphiuma species, by contrast, are dependent upon air-breathing, have excellent lungs, inefficient (Siren) or no (Amphiuma) gills, and are obligate air-breathers with an acid-base status more similar to that of terrestrial tetrapods. As such, they can be considered to be air-breathing animals that live in water. Their response to the aquatic hypercarbia that they often encounter is to maintain intracellular pH (pH(i) ) and abandon extracellular pH regulation, a process that has been referred to as preferential pH(i) regulation. The acid-base status of some present-day tropical air-breathing fishes, and of Siren and Amphiuma, suggests that the acid-base transition from a low PCO(2) -low [] system typical of water-breathing fishes to the high PCO(2) -high [] systems of terrestrial tetrapods may have been completed before emergence onto land, and likely occurred in habitats that were typically both hypoxic and hypercarbic.

  18. Carbon sequestration and eruption hazards

    Science.gov (United States)

    Zhang, Y.

    2007-12-01

    In order to reduce the buildup of carbon dioxide in the atmosphere, proposals have been made to sequestrate carbon in ocean, or in coal mines and other underground formations. High gas concentration in ocean or underground formations has to potential to power gas-driven eruptions. In this presentation, possible eruption hazards are explored. Whenever carbon dioxide is sequestrated in the form of carbon dioxide gas, or dissolved and/or absorbed carbon dioxide, it is necessary to exercise caution to avoid gas-driven eruption hazard. It is long known that explosive volcanic eruptions are driven by H2O gas in magma. Lake eruptions powered by dissolved CO2 in lake bottom water were discovered in the 1980's (Kling et al., 1987; Zhang, 1996). Gas-driven ocean eruptions with mechanism similar to lake eruptions have been hypothesized (Zhang, 2003; Zhang and Kling, 2006) although not confirmed. Mud volcanos are commonly thought to be driven by methane-rich fluids in sediment (Milkov, 2000). Recently, Zhang et al. (2007) have proposed that coal outbursts in underground coal mines are driven by dissolved high CO2 concentration in coal, causing coal fragmentation and outburst. That is, coal outbursts may be regarded as a new type of gas-driven eruptions. Therefore, high concentrations of free gas or dissolved/absorbed gas may power eruptions of magma, lake water, ocean water, sediment, and coal. Gas- driven volcanic, lake and ocean eruptions are due to volume expansion from bubble growth, whereas gas-driven coal and sediment eruptions are due to high gas-pressure, leading to fragmentation of coal and sediment. (In explosive volcanism, magma fragmentation is also a critical point.) The threshold conditions for many of these eruptions are not known yet. In planning large (industrial) scale injection of CO2 into a natural reservoir, it is important to know the eruption threshold and design the injection scheme accordingly. More safe sequestration in terms of eruption hazards would

  19. Semicontinuous measurements of gas-particle partitioning of organic acids in a ponderosa pine forest using a MOVI-HRToF-CIMS

    Science.gov (United States)

    Yatavelli, R. L. N.; Stark, H.; Thompson, S. L.; Kimmel, J. R.; Cubison, M. J.; Day, D. A.; Campuzano-Jost, P.; Palm, B. B.; Hodzic, A.; Thornton, J. A.; Jayne, J. T.; Worsnop, D. R.; Jimenez, J. L.

    2014-02-01

    Hundreds of gas- and particle-phase organic acids were measured in a rural ponderosa pine forest in Colorado, USA, during BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen - Rocky Mountain Biogenic Aerosol Study). A recently developed micro-orifice volatilization impactor high-resolution time-of-flight chemical ionization mass spectrometer (MOVI-HRToF-CIMS) using acetate (CH3C(O)O-) as the reagent ion was used to selectively ionize and detect acids semicontinuously from 20 to 30 August 2011, with a measurement time resolution of ~1.5 h. At this site 98% of the organic acid mass is estimated to be in the gas phase, with only ~2% in the particle phase. We investigated gas-particle partitioning, quantified as the fraction in the particle phase (Fp), of C1-C18 alkanoic acids, six known terpenoic acids, and bulk organic acids vs. carbon number. Data were compared to the absorptive partitioning model and suggest that bulk organic acids at this site follow absorptive partitioning to the organic aerosol mass. The rapid response (<1-2 h) of partitioning to temperature changes for bulk acids suggests that kinetic limitations to equilibrium are minor, which is in contrast to conclusions of some recent laboratory and field studies, possibly due to lack of very low ambient relative humidities at this site. Time trends for partitioning of individual and groups of acids were mostly captured by the model, with varying degrees of absolute agreement. Species with predicted substantial fractions in both the gas and particle phases show better absolute agreement, while species with very low predicted fractions in one phase often show poor agreement, potentially due to thermal decomposition, inlet adsorption, or other issues. Partitioning to the aqueous phase is predicted to be smaller than to the organic phase for alkanoic and bulk acids, and has different trends with time and carbon number than observed experimentally. This is due

  20. Survey and Down-Selection of Acid Gas Removal Systems for the Thermochemical Conversion of Biomass to Ethanol with a Detailed Analysis of an MDEA System

    Energy Technology Data Exchange (ETDEWEB)

    Nexant, Inc., San Francisco, California

    2011-05-01

    The first section (Task 1) of this report by Nexant includes a survey and screening of various acid gas removal processes in order to evaluate their capability to meet the specific design requirements for thermochemical ethanol synthesis in NREL's thermochemical ethanol design report (Phillips et al. 2007, NREL/TP-510-41168). MDEA and selexol were short-listed as the most promising acid-gas removal agents based on work described in Task 1. The second report section (Task 2) describes a detailed design of an MDEA (methyl diethanol amine) based acid gas removal system for removing CO2 and H2S from biomass-derived syngas. Only MDEA was chosen for detailed study because of the available resources.

  1. Survival of gas phase amino acids and nucleobases in space radiation conditions

    Science.gov (United States)

    Pilling, S.; Andrade, D. P. P.; de Castilho, R. B.; Cavasso-Filho, R. L.; Lago, A. F.; Coutinho, L. H.; de Souza, G. G. B.; Boechat-Roberty, H. M.; de Brito, A. Naves

    2008-10-01

    We present experimental studies on the photoionization and photodissociation processes (photodestruction) of gaseous amino acids and nucleobases in interstellar and interpla-netary radiation analogs conditions. The measurements have been undertaken at the Brazilian Synchrotron Light Laboratory (LNLS), employing vacuum ultraviolet (VUV) and soft X-ray photons. The experimental set up basically consists of a time-of-flight mass spectrometer kept under high vacuum conditions. Mass spectra were obtained using a photoelectron photoion coincidence technique. We have shown that the amino acids are effectively more destroyed (up to 70 80%) by the stellar radiation than the nucleobases, mainly in the VUV. Since polycyclic aromatic hydrocarbons have the same survival capability and seem to be ubiquitous in the ISM, it is not unreasonable to predict that nucleobases could survive in the interstellar medium and/or in comets, even as a stable cation.

  2. Survival of gas phase amino acids and nucleobases in space radiation conditions

    CERN Document Server

    Pilling, S; de Castilho, R B; Cavasso-Filho, R L; Lago, A F; Coutinho, L H; de Souza, G G B; Boechat-Roberty, H M; de Brito, A Naves

    2008-01-01

    We present experimental studies on the photoionization and photodissociation processes (photodestruction) of gaseous amino acids and nucleobases in interstellar and interplanetary radiation conditions analogs. The measurements have been undertaken at the Brazilian Synchrotron Light Laboratory (LNLS), employing vacuum ultraviolet (VUV) and soft X-ray photons. The experimental set up basically consists of a time-of-flight mass spectrometer kept under high vacuum conditions. Mass spectra were obtained using photoelectron photoion coincidence technique. We have shown that the amino acids are effectively more destroyed (up to 70-80%) by the stellar radiation than the nucleobases, mainly in the VUV. Since polycyclic aromatic hydrocarbons have the same survival capability and seem to be ubiquitous in the ISM, it is not unreasonable to predict that nucleobases could survive in the interstellar medium and/or in comets, even as a stable cation.

  3. Survival of gas phase amino acids and nucleobases in space radiation conditions

    OpenAIRE

    Pilling, S.; Andrade, D. P. P.; de Castilho, R. B.; Cavasso-Filho, R L; Lago, A. F.; de Coutinho, L. H.; de Souza, G. G. B.; Boechat-Roberty, H. M.; de Brito, A. Naves

    2008-01-01

    We present experimental studies on the photoionization and photodissociation processes (photodestruction) of gaseous amino acids and nucleobases in interstellar and interplanetary radiation conditions analogs. The measurements have been undertaken at the Brazilian Synchrotron Light Laboratory (LNLS), employing vacuum ultraviolet (VUV) and soft X-ray photons. The experimental set up basically consists of a time-of-flight mass spectrometer kept under high vacuum conditions. Mass spectra were ob...

  4. Optimization design of mixed amine method for removal of acid gas process%混合胺法脱酸工艺的优化设计

    Institute of Scientific and Technical Information of China (English)

    王志祥

    2016-01-01

    利用混合胺法脱除天然气中的酸性气体,投资少、能耗低、CO2净化度高,脱除效果显著。%This paper,we propose use mixed amine method to remove acid gas from natural gas. This method has less investment,low energy consumption,high purification degree of CO2,and removal effect is remarkable.

  5. 水和弱酸对过氧化氢异丙苯热危险性的影响%Influence of water and weak acid on thermal hazard of cumene hydroperoxide

    Institute of Scientific and Technical Information of China (English)

    金满平; 孙峰; 石宁; 谢传欣

    2012-01-01

    In order to study the influence of water and weak acid on the thermal hazard of cumene hydroperoxide (CHP) ,the thermal decomposition of CHP and CHP mixtures with different contents of water and weak acid and different pH of weak acid in the air was studied by C600 calorimeter. The corresponding kinetic and thermodynamic parameters based on experimental data were obtained,and the Semenov model was used to calculate the self accelerating decomposition temperature (SADT). The results show that small amounts of water and weak acid reduce the initial exothermic temperature,peak exothermic temperature and activation energy. The pH of weak acid also affects thermal hazard of CHP. As the pH of weak acid decreases,it is easier for the CHP decomposition reaction to occur. Calculated SADT of CHP is 84℃. The comparison on the calculated SADT results indicates that small amounts of water and weak acid reduce the SADT of CHP,and at lower pH of weak acid,the SADT also decreases.%为研究水和弱酸对过氧化氢异丙苯(CHP)热危险性的影响,利用C600微量热仪研究了CHP及CHP与不同含量水、不同含量弱酸、不同pH值弱酸的混合物在空气中受热分解的反应和放热特性,根据实验数据得出了相应的动力学和热力学参数,利用Semenov热爆炸模型计算出了自加速分解温度(SADT).结果表明:少量的水和弱酸都能够使CHP的起始放热温度、最大放热温度、活化能降低;弱酸的pH值对CHP的热危险性也有影响,pH值越低,CHP的热危险性越大;计算得到CHP的SADT为84℃,通过对CHP及CHP与不同含量水、弱酸和不同pH值弱酸混合物SADT进行比较,发现少量的水和弱酸均能降低CHP的SADT,弱酸的pH值对SADT也有影响,pH值越低,CHP与弱酸混合物的SADT越小.

  6. Detection of lysergic acid diethylamide (LSD) in urine by gas chromatography-ion trap tandem mass spectrometry.

    Science.gov (United States)

    Sklerov, J H; Kalasinsky, K S; Ehorn, C A

    1999-10-01

    A confirmatory method for the detection and quantitation of lysergic acid diethylamide (LSD) is presented. The method employs gas chromatography-tandem mass spectrometry (GC-MS-MS) using an internal ionization ion trap detector for sensitive MS-MS-in-time measurements of LSD extracted from urine. Following a single-step solid-phase extraction of 5 mL of urine, underivatized LSD can be measured with limits of quantitation and detection of 80 and 20 pg/mL, respectively. Temperature-programmed on-column injections of urine extracts were linear over the concentration range 20-2000 pg/mL (r2 = 0.999). Intraday and interday coefficients of variation were LSD-positive samples in this laboratory. Comparisons with alternate GC-MS methods and extraction procedures are discussed.

  7. Target identification of volatile metabolites to allow the differentiation of lactic acid bacteria by gas chromatography-ion mobility spectrometry.

    Science.gov (United States)

    Gallegos, Janneth; Arce, Cristina; Jordano, Rafael; Arce, Lourdes; Medina, Luis M

    2017-04-01

    The purpose of this work was to study the potential of gas chromatography-ion mobility spectrometry (GC-IMS) to differentiate lactic acid bacteria (LAB) through target identification and fingerprints of volatile metabolites. The LAB selected were used as reference strains for their influence in the flavour of cheese. The four strains of LAB can be distinguished by the fingerprints generated by the volatile organic compounds (VOCs) emitted. 2-butanone, 2-pentanone, 2-heptanone and 3-methyl-1-butanol were identified as relevant VOCs for Lactobacillus casei and Lactobacillus paracasei subsp. paracasei. 2-Butanone and 3-methyl-1-butanol were identified in Lactococcus lactis subsp. lactis and Lactococcus cremoris subsp. cremoris. The IMS signals monitoring during a 24-30h period showed the growth of the LAB in vitro. The results demonstrated that GC-IMS is a useful technology for bacteria recognition and also for screening the aromatic potential of new isolates of LAB.

  8. Peak alignment and robust principal component analysis of gas chromatograms of fatty acid methyl esters and volatiles

    DEFF Research Database (Denmark)

    Frosch, Stina; Jørgensen, Bo

    2007-01-01

    Gas chromatograms of fatty acid methyl esters and of volatile lipid oxidation products from fish lipid extracts are analyzed by multivariate data analysis [principal component analysis (PCA)]. Peak alignment is necessary in order to include all sampled points of the chromatograms in the data set....... The ability of robust algorithms to deal with outlier problems, including both sample-wise and element-wise outliers, and the advantages and drawbacks of two robust PCA methods, robust PCA (ROBPCA) and robust singular value decomposition when analysing these GC data were investigated. The results show...... that the usage of ROPCA is advantageous, compared with traditional PCA, when analysing the entire profile of chromatographic data in cases of sub-optimally aligned data. It also demonstrates how choosing the most robust PCA (sample or element-wise) depends on the type of outliers present in the data set....

  9. Stable isotope dilution analysis of salicylic acid and hydroquinone in human skin samples by gas chromatography with mass spectrometric detection.

    Science.gov (United States)

    Judefeind, Anja; van Rensburg, Peet Jansen; Langelaar, Stephan; du Plessis, Jeanetta

    2007-06-01

    A sensitive and accurate gas chromatographic-mass spectrometric (GC-MS) method has been developed for the quantitative determination of salicylic acid (SA) and hydroquinone (HQ) from human skin samples and cosmetic emulsions. Deuterium labeled SA-d(6) and HQ-d(6) were used as internal standards (IS). The samples were extracted with methanol, dried under nitrogen and derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)+1% trimethylchlorosilane (TMCS). Quantification was performed in SIM mode with a limit of quantification (LOQ) of 50 ng ml(-1) for SA and 10 ng ml(-1) for HQ. The inter-day variation (R.S.D.) was less than 5% and the accuracy was better than 13.3% for both compounds. The recoveries from the different matrices ranged between 93.1 and 103.3% for SA, and 97.3 and 100.8% for HQ.

  10. COMPUTERS HAZARDS

    Directory of Open Access Journals (Sweden)

    Andrzej Augustynek

    2007-01-01

    Full Text Available In June 2006, over 12.6 million Polish users of the Web registered. On the average, each of them spent 21 hours and 37 minutes monthly browsing the Web. That is why the problems of the psychological aspects of computer utilization have become an urgent research subject. The results of research into the development of Polish information society carried out in AGH University of Science and Technology, under the leadership of Leslaw H. Haber, in the period from 2000 until present time, indicate the emergence dynamic changes in the ways of computer utilization and their circumstances. One of the interesting regularities has been the inverse proportional relation between the level of computer skills and the frequency of the Web utilization.It has been found that in 2005, compared to 2000, the following changes occurred:- A significant drop in the number of students who never used computers and the Web;- Remarkable increase in computer knowledge and skills (particularly pronounced in the case of first years student- Decreasing gap in computer skills between students of the first and the third year; between male and female students;- Declining popularity of computer games.It has been demonstrated also that the hazard of computer screen addiction was the highest in he case of unemployed youth outside school system. As much as 12% of this group of young people were addicted to computer. A lot of leisure time that these youths enjoyed inducted them to excessive utilization of the Web. Polish housewives are another population group in risk of addiction to the Web. The duration of long Web charts carried out by younger and younger youths has been another matter of concern. Since the phenomenon of computer addiction is relatively new, no specific therapy methods has been developed. In general, the applied therapy in relation to computer addition syndrome is similar to the techniques applied in the cases of alcohol or gambling addiction. Individual and group

  11. Volcanic hazards to airports

    Science.gov (United States)

    Guffanti, M.; Mayberry, G.C.; Casadevall, T.J.; Wunderman, R.

    2009-01-01

    Volcanic activity has caused significant hazards to numerous airports worldwide, with local to far-ranging effects on travelers and commerce. Analysis of a new compilation of incidents of airports impacted by volcanic activity from 1944 through 2006 reveals that, at a minimum, 101 airports in 28 countries were affected on 171 occasions by eruptions at 46 volcanoes. Since 1980, five airports per year on average have been affected by volcanic activity, which indicates that volcanic hazards to airports are not rare on a worldwide basis. The main hazard to airports is ashfall, with accumulations of only a few millimeters sufficient to force temporary closures of some airports. A substantial portion of incidents has been caused by ash in airspace in the vicinity of airports, without accumulation of ash on the ground. On a few occasions, airports have been impacted by hazards other than ash (pyroclastic flow, lava flow, gas emission, and phreatic explosion). Several airports have been affected repeatedly by volcanic hazards. Four airports have been affected the most often and likely will continue to be among the most vulnerable owing to continued nearby volcanic activity: Fontanarossa International Airport in Catania, Italy; Ted Stevens Anchorage International Airport in Alaska, USA; Mariscal Sucre International Airport in Quito, Ecuador; and Tokua Airport in Kokopo, Papua New Guinea. The USA has the most airports affected by volcanic activity (17) on the most occasions (33) and hosts the second highest number of volcanoes that have caused the disruptions (5, after Indonesia with 7). One-fifth of the affected airports are within 30 km of the source volcanoes, approximately half are located within 150 km of the source volcanoes, and about three-quarters are within 300 km; nearly one-fifth are located more than 500 km away from the source volcanoes. The volcanoes that have caused the most impacts are Soufriere Hills on the island of Montserrat in the British West Indies

  12. The effect of H2SO4 - amine clustering on chemical ionization mass spectrometry (CIMS) measurements of gas-phase sulfuric acid

    DEFF Research Database (Denmark)

    Kurten, T.; Petaja, T.; Smith, J.;

    2011-01-01

    by the CIMS instrument, though the most reliable computational methods employed predict this fraction to be small; on the order of ten percent or less. Third, the amine molecules will evaporate practically immediately after charging, thus evading detection. These effects may need to be taken into account......The state-of-the art method for measuring atmospheric gas-phase sulfuric acid is chemical ionization mass spectrometry (CIMS) based on nitrate reagent ions. We have assessed the possible effect of the sulfuric acid molecules clustering with base molecules on CIMS measurements using computational...... chemistry. From the computational data, three conclusions can be drawn. First, a significant fraction of the gas-phase sulfuric acid molecules are very likely clustered with amines if the amine concentration is around or above a few ppt. Second, some fraction of these acid-amine clusters may not be charged...

  13. Pepsin and bile acid concentrations in sputum of mustard gas exposed patients

    Directory of Open Access Journals (Sweden)

    Ashraf Karbasi

    2013-01-01

    Full Text Available Background/Aim: Gastro-esophageal reflux has been suggested to be associated with several pulmonary complications such as asthma, and post-transplant bronchiolitis obliterans (BO. Pepsin or bile salts in the sputum is shown to be an optimal molecular marker of gastric contents macro/micro aspiration. In this study, we investigated sputum pepsin as a marker of micro-aspiration in sulfur mustard (SM exposed cases compared to healthy controls. Materials and Methods: In a case controlled study, 26 cases with BO and 12 matched healthy controls were recruited and all cases were symptomatic and their exposure to SM was previously documented during Iran-Iraq conflict. Pepsin levels in sputum and total bile acids were measured using enzymatic assay. The severity of respiratory disorder was categorized based upon the spirometric values. Result: The average concentration of pepsin in sputum was higher in the case group (0.29 ± 0.23 compared with healthy subjects (0.13 ± 0.07; P ± 0.003. Moreover, the average concentration of bile acids in the sputum cases was not significantly different in comparison to the controls ( P = 0.5. Conclusion: Higher pepsin concentrations in sputum of SM exposed patients compared with healthy control subjects indicate the occurrence of significantly more gastric micro-aspiration in SM exposed patients.

  14. A study about dimers formation of formic acid in gas phase and in the valence region

    Energy Technology Data Exchange (ETDEWEB)

    Arruda, M.S. [Universidade Federal do Reconcavo da Bahia (UFRB), Amargosa, BA (Brazil); Prudente, F.V.; Marinho, R.R.T.; Nascimento, E.M. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil)

    2012-07-01

    Full text: Study of simple pre-biotic molecules takes great importance for understanding about complex organic molecules formation like amino acids, proteins and nucleobases within the DNA and RNA. A hypothesis for the appearance of nucleobases is that they could have been synthesized from simpler organic composites contained in interstellar medium (ISM), meteorites and asteroids. Lots of experiments have demonstrated that it is possible to produce complex pre-biotic molecules from simpler molecules under environments that simulate the ISM. Thus, we have performed a theoretical and experimental study about photoionization and photofragmentation processes of simple pre-biotic molecules that are important in the synthesis of complex biomolecules. In this work particularly, we performed photoionization and photofragmentation process of formic acid-D2 (CDOOD) in order to verify if some molecular fragmentations coming from dimers that could be formed before ionization region at TOF mass spectrometer. Experimentally, we measured these molecules mass spectra in gaseous phase. These spectra were got as function of pressures in experimental chamber, temperature samples and photon energy, in the vacuum ultraviolet region, between 11 and 20 eV. These data had been obtained in the Brazilian Laboratory of Synchrotron Light, by using mass spectrometer of flight time. The mass spectra had been obtained by using the photoelectron photoion coincidence technique, PEPICO. For a better understanding of experimental results, we have made a theoretical analysis of the photofragmentation by using Density Functional Theory. (author)

  15. Influence of gas-particle partitioning on ammonia and nitric acid fluxes above a deciduous forest in the Midwestern USA

    Science.gov (United States)

    Hansen, K.; Sørensen, L. L.; Hornsby, K. E.; Boegh, E.; Pryor, S. C.

    2013-12-01

    Quantifying the atmosphere-biosphere exchange of reactive nitrogen gasses (including ammonia (NH3) and nitric acid (HNO3)) is crucial to assessing the impact of anthropogenic activities on natural and semi-natural ecosystems. However, measuring the deposition of reactive nitrogen is challenging due to bi-directionality of the flux, and the dynamics of the chemical gas/aerosol equilibrium of NH3 and HNO3 (or other atmospheric acids) with aerosol-phase ammonium (NH4+) and nitrate (NO3-). NH3 and HNO3 are both very reactive and typically exhibit higher deposition velocities than aerosol NH4+. Therefore, the phase partitioning between gas and aerosol phases can have a significant effect on local budgets and atmospheric transport distances (Nemitz et al., Atmos. Chem. Phys., 2004). In this study, fluxes of NH3, HNO3 and carbon dioxide (CO2) along with size-resolved N-aerosol concentrations are measured above the deciduous forest, Morgan Monroe State Forest (MMSF) in south-central Indiana (39°53'N, 86°25'W) during a field campaign. Two relaxed eddy accumulation (REA) systems are used to measure fluxes and concentrations of NH3 and HNO3 at 44 m. The NH3 REA system operates based on wet effluent diffusion denuders with detection by florescence and half-hourly flux measurements are calculated. HNO3 REA system is based on gas capture on sodium chloride (NaCl) coated denuders with subsequent analysis by ion-chromatography, and the resulting fluxes have a resolution of 3-4 hours. CO2 fluxes are measured by eddy covariance using a closed-path Licor LI-7500, while two MSP MOUDI-110 impactors are used to measure the 24-hourly average inorganic and 48 hourly averaged organic ion concentrations in 11 size bins, respectively, just above the canopy level (28 m). The results of this field campaign are used to quantify the fluxes of NH3, HNO3, CO2 to/from the forest during the transition towards senescence, and to investigate process-level controls (e.g. the role of phase

  16. Separation of cis/trans fatty acid isomers on gas chromatography compared to the Ag-TLC method

    Directory of Open Access Journals (Sweden)

    Sundaresan, A.

    2013-03-01

    Full Text Available The present study investigates the separation of the cis/trans isomers of fatty acids on the 75 m SP2560 column under different gas chromatographic (GC conditions including an isothermal program and a time-temperature program. The time-temperature program showed improved separation of cis/trans isomers of C14:1, C16:1, C18:1, C18:2 and C18:3 fatty acids along with short chain fatty acids compared to the isothermal program. The separation of trans/trans isomers of C18:1 fatty acids including elaidic acid (C18:1 ∆9t and vaccenic acid (C18:1 ∆11t was difficult with the time-temperature program. The thin layer chromatography impregnated with silver nitrate (Ag- TLC method was performed to separate cis/trans fractions and GC analysis was carried out with the trans fraction. But GC analysis showed a co-elution of trans isomers of C18:1 fatty acid. Thus the study shows that a time-temperature programmed GC method with the highly polar cyanopropyl column is sufficient to resolve trans fatty acids along with short chain fatty acids when a large number of samples has to be analyzed.El presente estudio investiga la separación de isómeros cis/trans de ácidos grasos mediante cromatografía de gases (GC utilizando una columna de SP2560 de 75 m y diferentes condiciones que incluyen un programa isotérmico y una programación temperatura-tiempo. La programación temperatura- tiempo mostró una mejor separación de isómeros cis / trans de los ácidos grasos C14:1, C16:1, C18:1, C18:2 y C18:3 con los ácidos grasos de cadena corta en comparación con el programa isotermo. La separación de los isómeros trans/trans de los ácidos grasos C18:1 incluyendo ácido elaídico (C18:1 Δ9t y ácido vaccénico (C18:1Δ11t fué difícil mediante programación temperatura-tiempo. La cromatografía en capa fina impregnada con nitrato de plata (Ag-TLC se realizó para separar fracciones cis/trans y el análisis de la fracciones se llevó a cabo mediante GC. El an

  17. Electrochemical gas sensors based on paper-supported room-temperature ionic liquids for improved analysis of acid vapours.

    Science.gov (United States)

    Toniolo, Rosanna; Dossi, Nicolò; Pizzariello, Andrea; Casagrande, Alice; Bontempelli, Gino

    2013-04-01

    A prototype of a fast-response task-specific amperometric gas sensor based on paper-supported room-temperature ionic liquids (RTILs) is proposed here for improved analysis of volatile acid species. It consists of a small filter paper foil soaked with a RTIL mixture containing an ionic liquid whose anion (acetate) displays a basic character, upon which three electrodes are screen printed by carbon ink profiting from a suitable mask. It takes advantage of the high electrical conductivity and negligible vapour pressure of RTILs and of their easy immobilization into a porous and inexpensive supporting material such as paper. The performance of this device, used as a wall-jet amperometric detector for flow injection analyses of headspace samples in equilibrium with aqueous solutions at controlled concentrations, was evaluated for phenol and 1-butanethiol vapours which were adopted as model acid gaseous analytes. The results obtained showed that the quite high potentials required for the detection of these analytes are lowered significantly, thanks to the addition of the basic acetate RTIL. In such a way, overlap with the medium discharge is avoided, and the possible adverse effect of interfering species is minimised. The sensor performance was quite satisfactory (detection limits, ca. 0.3 μM; dynamic range, ca. 1-200 μM, both referred to solution concentrations; correlation coefficients in the range 0.993-0.997; repeatability, ± 6% RSD; long-term stability, 9%); thus suggesting the possible use of this device for manifold applications.

  18. High-throughput capillary gas chromatography for the determination of polychlorinated biphenyls and fatty acid methyl esters in food samples.

    Science.gov (United States)

    Sandra, Pat; David, Frank

    2002-01-01

    High-throughput capillary gas chromatography (CGC) methods, developed during the Belgian 1999 "dioxin" food crisis, for the determination of the contaminating polychlorinated biphenyls (PCBs) and the fatty acid composition of the lipids are described. For PCB analysis, the fat obtained by ultrasonic extraction is fractionated by matrix solid-phase dispersion, and the PCBs are analyzed by CGC-electron capture detection on a 10-mL x 100-microm-i.d. HP-5MS column. Analytical conditions for the high-speed column are deduced from analyses on conventional CGC columns using the method translation software. The concept of retention time locking is implemented to facilitate the elucidation of the PCB markers. The fatty acid methyl esters (FAMEs) are prepared by the sodium methylate procedure on part of the ultrasonic extract followed by analysis on 10-mL x 100-microm-i.d. HP-WAX or BPX-70 capillary columns. By optimizing both the sample preparation and CGC analysis, the throughput is more than fifty PCB and FAME samples per day with the same robustness as conventional methods.

  19. Characteristic chromatographic fingerprint study of short-chain fatty acids in human milk, infant formula, pure milk and fermented milk by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Jiang, Zhenzuo; Liu, Yanan; Zhu, Yan; Yang, Jing; Sun, Lili; Chai, Xin; Wang, Yuefei

    2016-09-01

    Human milk, infant formula, pure milk and fermented milk as food products or dietary supplements provide a range of nutrients required to both infants and adults. Recently, a growing body of evidence has revealed the beneficial roles of short-chain fatty acids (SCFAs), a subset of fatty acids produced from the fermentation of dietary fibers by gut microbiota. The objective of this study was to establish a chromatographic fingerprint technique to investigate SCFAs in human milk and dairy products by gas chromatography coupled with mass spectrometry. The multivariate method for principal component analysis assessed differences between milk types. Human milk, infant formula, pure milk and fermented milk were grouped independently, mainly because of differences in formic acid, acetic acid, propionic acid and hexanoic acid levels. This method will be important for the assessment of SCFAs in human milk and various dairy products.

  20. A possible role for bile acid in the control of methanogenesis and the accumulation of hydrogen gas in the human colon.

    Science.gov (United States)

    Florin, T H; Jabbar, I A

    1994-01-01

    This study investigated a possible role for primary bile acid in the control of methanogenesis in the human colon. Production of hydrogen and methane was measured in anaerobic faecal cultures derived from faeces of six 'non-methanogenic' and three methanogenic healthy humans. Using a sensitive technique for gas measurement, methane was detected in all faecal cultures, including those from 'non-methanogenic' humans. Bile acid inhibited methanogenesis in a dose-response fashion in the in vitro 'non-methanogenic' and methanogenic faecal cultures. Inhibition was significant at bile acid concentrations > 0.05%. Methanogenesis correlated with methanogen (methanogenic bacteria) numbers. If this inhibition occurs in vivo, then it would explain much of the epidemiology of non-methanogenesis in humans. From an analysis of net hydrogen production by the faecal cultures, it is inferred that bile acid inhibits other hydrogen-consuming bacteria in addition to methanogens. These in vitro data suggest a major role for bile acid in the accumulation of hydrogen gas in the colon. Possible links between bile acid induced accumulation of gas and irritable bowel syndrome are discussed.

  1. OPTIMIZING TECHNOLOGY TO REDUCE MERCURY AND ACID GAS EMISSIONS FROM ELECTRIC POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey C. Quick; David E. Tabet; Sharon Wakefield; Roger L. Bon

    2005-10-01

    Maps showing potential mercury, sulfur, chlorine, and moisture emissions for U.S. coal by county of origin were made from publicly available data (plates 1, 2, 3, and 4). Published equations that predict mercury capture by emission control technologies used at U.S. coal-fired utilities were applied to average coal quality values for 169 U.S. counties. The results were used to create five maps that show the influence of coal origin on mercury emissions from utility units with: (1) hot-side electrostatic precipitator (hESP), (2) cold-side electrostatic precipitator (cESP), (3) hot-side electrostatic precipitator with wet flue gas desulfurization (hESP/FGD), (4) cold-side electrostatic precipitator with wet flue gas desulfurization (cESP/FGD), and (5) spray-dry adsorption with fabric filter (SDA/FF) emission controls (plates 5, 6, 7, 8, and 9). Net (lower) coal heating values were calculated from measured coal Btu values, and estimated coal moisture and hydrogen values; the net heating values were used to derive mercury emission rates on an electric output basis (plate 10). Results indicate that selection of low-mercury coal is a good mercury control option for plants having hESP, cESP, or hESP/FGD emission controls. Chlorine content is more important for plants having cESP/FGD or SDA/FF controls; optimum mercury capture is indicated where chlorine is between 500 and 1000 ppm. Selection of low-sulfur coal should improve mercury capture where carbon in fly ash is used to reduce mercury emissions. Comparison of in-ground coal quality with the quality of commercially mined coal indicates that existing coal mining and coal washing practice results in a 25% reduction of mercury in U.S. coal before it is delivered to the power plant. Further pre-combustion mercury reductions may be possible, especially for coal from Texas, Ohio, parts of Pennsylvania and much of the western U.S.

  2. Impacts of ocean acidification on respiratory gas exchange and acid-base balance in a marine teleost, Opsanus beta.

    Science.gov (United States)

    Esbaugh, Andrew J; Heuer, Rachael; Grosell, Martin

    2012-10-01

    The oceanic carbonate system is changing rapidly due to rising atmospheric CO(2), with current levels expected to rise to between 750 and 1,000 μatm by 2100, and over 1,900 μatm by year 2300. The effects of elevated CO(2) on marine calcifying organisms have been extensively studied; however, effects of imminent CO(2) levels on teleost acid-base and respiratory physiology have yet to be examined. Examination of these physiological processes, using a paired experimental design, showed that 24 h exposure to 1,000 and 1,900 μatm CO(2) resulted in a characteristic compensated respiratory acidosis response in the gulf toadfish (Opsanus beta). Time course experiments showed the onset of acidosis occurred after 15 min of exposure to 1,900 and 1,000 μatm CO(2), with full compensation by 2 and 4 h, respectively. 1,900-μatm exposure also resulted in significantly increased intracellular white muscle pH after 24 h. No effect of 1,900 μatm was observed on branchial acid flux; however, exposure to hypercapnia and HCO(3)(-) free seawater compromised compensation. This suggests branchial HCO(3)(-) uptake rather than acid extrusion is part of the compensatory response to low-level hypercapnia. Exposure to 1,900 μatm resulted in downregulation in branchial carbonic anhydrase and slc4a2 expression, as well as decreased Na(+)/K(+) ATPase activity after 24 h of exposure. Infusion of bovine carbonic anhydrase had no effect on blood acid-base status during 1,900 μatm exposures, but eliminated the respiratory impacts of 1,000 μatm CO(2). The results of the current study clearly show that predicted near-future CO(2) levels impact respiratory gas transport and acid-base balance. While the full physiological impacts of increased blood HCO(3)(-) are not known, it seems likely that chronically elevated blood HCO(3)(-) levels could compromise several physiological systems and furthermore may explain recent reports of increased otolith growth during exposure to elevated CO(2).

  3. Molten Salt Catalysts for Sulfuric Acid Production and SO2 Removal From Flue Gas

    DEFF Research Database (Denmark)

    Eriksen, Kim Michael; Fehrmann, Rasmus

    1996-01-01

    The report summarises the results obtained during 3 years of collaboration between ICE/HT,University of Patras,GR and Department of Chemistry,DTU,DK , supported by EU through a BRITE/EURAM project.The project has been concerned with fundamental investigations on the complex , redox and compound c...... chemistry of the V2O5 based sulfuric acid catalysts and model systems......The report summarises the results obtained during 3 years of collaboration between ICE/HT,University of Patras,GR and Department of Chemistry,DTU,DK , supported by EU through a BRITE/EURAM project.The project has been concerned with fundamental investigations on the complex , redox and compound...

  4. Eddy covariance captures four-phase crassulacean acid metabolism (CAM) gas exchange signature in Agave.

    Science.gov (United States)

    Owen, Nick A; Choncubhair, Órlaith Ní; Males, Jamie; Del Real Laborde, José Ignacio; Rubio-Cortés, Ramón; Griffiths, Howard; Lanigan, Gary

    2016-02-01

    Mass and energy fluxes were measured over a field of Agave tequilana in Mexico using eddy covariance (EC) methodology. Data were gathered over 252 d, including the transition from wet to dry periods. Net ecosystem exchanges (FN,EC ) displayed a crassulacean acid metabolism (CAM) rhythm that alternated from CO2 sink at night to CO2 source during the day, and partitioned canopy fluxes (FA,EC ) showed a characteristic four-phase CO2 exchange pattern. Results were cross-validated against diel changes in titratable acidity, leaf-unfurling rates, energy exchange fluxes and reported biomass yields. Projected carbon balance (g C m(-2)  year(-1) , mean ± 95% confidence interval) indicated the site was a net sink of -333 ± 24, of which contributions from soil respiration were +692 ± 7, and FA,EC was -1025 ± 25. EC estimated biomass yield was 20.1 Mg (dry) ha(-1)  year(-1) . Average integrated daily FA,EC was -234 ± 5 mmol CO2  m(-2)  d(-1) and persisted almost unchanged after 70 d of drought conditions. Regression analyses were performed on the EC data to identify the best environmental predictors of FA . Results suggest that the carbon acquisition strategy of Agave offers productivity and drought resilience advantages over conventional semi-arid C3 and C4 bioenergy candidates.

  5. The tropospheric processing of acidic gases and hydrogen sulphide in volcanic gas plumes as inferred from field and model investigations

    Directory of Open Access Journals (Sweden)

    A. Aiuppa

    2007-01-01

    Full Text Available Improving the constraints on the atmospheric fate and depletion rates of acidic compounds persistently emitted by non-erupting (quiescent volcanoes is important for quantitatively predicting the environmental impact of volcanic gas plumes. Here, we present new experimental data coupled with modelling studies to investigate the chemical processing of acidic volcanogenic species during tropospheric dispersion. Diffusive tube samplers were deployed at Mount Etna, a very active open-conduit basaltic volcano in eastern Sicily, and Vulcano Island, a closed-conduit quiescent volcano in the Aeolian Islands (northern Sicily. Sulphur dioxide (SO2, hydrogen sulphide (H2S, hydrogen chloride (HCl and hydrogen fluoride (HF concentrations in the volcanic plumes (typically several minutes to a few hours old were repeatedly determined at distances from the summit vents ranging from 0.1 to ~10 km, and under different environmental conditions. At both volcanoes, acidic gas concentrations were found to decrease exponentially with distance from the summit vents (e.g., SO2 decreases from ~10 000 μg/m3at 0.1 km from Etna's vents down to ~7 μg/m3 at ~10 km distance, reflecting the atmospheric dilution of the plume within the acid gas-free background troposphere. Conversely, SO2/HCl, SO2/HF, and SO2/H2S ratios in the plume showed no systematic changes with plume aging, and fit source compositions within analytical error. Assuming that SO2 losses by reaction are small during short-range atmospheric transport within quiescent (ash-free volcanic plumes, our observations suggest that, for these short transport distances, atmospheric reactions for H2S and halogens are also negligible. The one-dimensional model MISTRA was used to simulate quantitatively the evolution of halogen and sulphur compounds in the plume of Mt. Etna. Model predictions support the hypothesis of minor HCl chemical processing during plume transport, at least in cloud-free conditions. Larger

  6. Fingerprint vibrational spectra of protonated methyl esters of amino acids in the gas phase.

    Science.gov (United States)

    Simon, Aude; Macaleese, Luke; Maître, Philippe; Lemaire, Joël; McMahon, Terrance B

    2007-03-14

    Infrared spectra of the protonated monomers of glycine, alanine, valine, and leucine methyl esters are presented. These protonated species are generated in the gas phase via matrix assisted laser desorption ionization (MALDI) within the cell of a Fourier transform ion cyclotron resonance spectrometer (FTICR) where they are subsequently mass selected as the only species trapped in the FTICR cell. Alternatively, they have also been generated by electrospray ionization and transferred to a Paul ion-trap mass spectrometer where they are similarly isolated. In both cases IR spectra are then derived from the frequency dependence of the infrared multiple photon dissociation (IRMPD) in the mid-infrared region (1000-2200 cm(-1)), using the free electron laser facility Centre de Laser Infrarouge d'Orsay (CLIO). IR bands are assigned by comparison with the calculated vibrational spectra of the lowest energy isomers using density functional theory (DFT) calculations. There is in general good agreement between experimental IRMPD spectra and calculated IR absorption spectra for the lowest energy conformer which provides evidence for conformational preferences. The two different approaches to ion generation and trapping yield IRMPD spectra that are in excellent agreement.

  7. Direct determination of flavor relevant and further branched-chain fatty acids from sheep subcutaneous adipose tissue by gas chromatography with mass spectrometry.

    Science.gov (United States)

    Kaffarnik, Stefanie; Preuß, Siegfried; Vetter, Walter

    2014-07-11

    4-Methyloctanoic acid, 4-ethyloctanoic acid and 4-methylnonanoic acid are key-flavor compounds of sheep and goat. Yet, the low amounts of these volatile branched-chain fatty acids (vBCFAs) in the fat of the ruminants hampered their determination on a routine basis. In this work we developed a gas chromatography/mass spectrometry selected ion monitoring (GC/MS-SIM) method for the direct determination of the vBCFAs as methyl esters, which were obtained after transesterification of subcutaneous adipose tissue of sheep. The excellent sensitivity of the GC/MS-SIM method (limit of quantification, LOQ, 3.6-4.8μg/g; limit of detection, LOD, 1.1-1.4μg/g for 4-Me-8:0, 4-Et-8:0 and 4-Me-9:0) enabled us to determine the three vBCFAs without an enrichment step. Subcutaneous adipose sheep tissue of three different breeds contained 23-88μg/g 4-methyloctanoic acid, 13-26μg/g 4-ethyloctanoic acid and ∼2.9-18μg/g 4-methylnonanoic acid. Since all fatty acids were present in the FAME fraction, the samples could be screened for further branched-chain FAMEs. After elimination of unsaturated fatty acids by hydrogenation (the presence of some unsaturated fatty acids could be verified by this measure), additional measurements in SIM and full scan modes of methyl esters and picolinyl esters enabled the determination of further 97 saturated fatty acids in the samples with eight to 20 carbons. The method is suited for routine analysis and may be useful to investigate the reasons for the abundance/absence of 4-methyloctanoic acid, 4-ethyloctanoic acid and 4-methylnonanoic acid and further branched-chain fatty acids in sheep and goat.

  8. Radiation hazard control report

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Taeko; Inagaki, Masayo; Morishima, Hiroshige; Araki, Yasusuke; Takiguchi, Chizuko; Hiraji, Chihiro; Nagai, Shoya [Kinki Univ., Higashi-Osaka, Osaka (Japan)

    2003-03-01

    The document of radiation hazard control from April 2001 to March 2002 in the research institute of atomic energy of Kinki University was reported and actual data were presented. 106 personnel were subjected to the control, the reactor maximal output was 1W with total output of 399,64 W center dot h for total 718.23 h and the institute underwent the inspection by Ministry of Education, Culture, Sports, Science and Technology for twice, which resulting in getting satisfactory evaluation. The control involved was for the personnel, laboratories and field. The first was done mainly with film badges and sometimes with pocket dosimeters, and revealed the exposure of 0.480 mSv at maximum. The laboratory dose equivalent was continuously measured with the ionization chamber area monitor and sometimes with the ionization chamber survey meters, GM tube survey meters and scintillation survey meters. The film badge and TLD were also used. In addition, concentrations of radioactivity were measured in the exhaust gas and water with the dust-monitor and overall-monitor, respectively, and surface densities by smear-method with 2 pi-gas flow and liquid scintillation counters. The field control was carried out by calculation of environmental gamma-ray dose equivalent rate based on monthly TLD dose data and by actual beta-ray measurement of environmental specimens collected at every 3 months. (J.P.N.)

  9. Radiation hazard control report

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Taeko; Inagaki, Masayo; Morishima, Hiroshige; Araki, Yasusuke; Takiguchi, Chizuko; Matsubayashi, Hideki; Hiraji, Chihiro [Kinki Univ., Higashi-Osaka, Osaka (Japan)

    2002-01-01

    The document of radiation hazard control from April 2000 to March 2001 in the research institute of atomic energy of Kinki University was reported and actual data were presented. Seventy five personnel were subjected to the control, the reactor maximal output was 1W with total output of 463.74 W center dot h for total 777.34 h and the institute underwent the inspection by Science and Technology Agency for 3 times, which resulting in getting satisfactory evaluation. The control involved was for the personnel, laboratories and field. The first was done mainly with film badges and sometimes with pocket dosimeters, and revealed the exposure of 0.264 mSv at maximum. The laboratory dose equivalent was continuously measured with the ionization chamber area monitor and sometimes with the ionization chamber survey meters, GM tube survey meters and scintillation survey meters. The film badge and TLD were also used. In addition, concentrations of radioactivity were measured in the exhaust gas and water with the dust-monitor and overall-monitor, respectively, and surface densities by smear-method with the 2 pi-gas flow and liquid scintillation counters. The field control was carried out by calculation of environmental gamma-ray dose equivalent rate based on monthly TLD dose data and by actual beta-ray measurement of environmental specimens collected at every 3 months. (J.P.N.)

  10. Lipid fatty acid profile analyses in liver and serum in rats with nonalcoholic steatohepatitis using improved gas chromatography-mass spectrometry methodology

    Science.gov (United States)

    Fatty acids (FA) are essential components of lipids and exhibit important biological functions. The analyses of FAs are routinely carried out by gas chromatography-mass spectrometry, after multi-step sample preparation. In this study, several key experimental factors were carefully examined, validat...

  11. High-resolution gas chromatography/mas spectrometry method for characterization and quantitative analysis of ginkgolic acids in ginkgo biloba plants, extracts, and dietary supplements

    Science.gov (United States)

    A high resolution GC/MS with Selected Ion Monitor (SIM) method focusing on the characterization and quantitative analysis of ginkgolic acids (GAs) in Ginkgo biloba L. plant materials, extracts and commercial products was developed and validated. The method involved sample extraction with (1:1) meth...

  12. 75 FR 43906 - Hazardous Materials: Requirements for the Storage of Explosives During Transportation

    Science.gov (United States)

    2010-07-27

    ... article that is designed to function by explosion--that is, an extremely rapid release of gas or heat--or... Description of hazard Examples 1.1 Mass explosion hazard....... Instantaneous explosion of grenades, mines... projected outward rockets and mass explosion hazard. at some distance. warheads. 1.3 Fire hazard and...

  13. Quantitative analysis of fatty-acid-based biofuels produced by wild-type and genetically engineered cyanobacteria by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Guan, Wenna; Zhao, Hui; Lu, Xuefeng; Wang, Cong; Yang, Menglong; Bai, Fali

    2011-11-11

    Simple and rapid quantitative determination of fatty-acid-based biofuels is greatly important for the study of genetic engineering progress for biofuels production by microalgae. Ideal biofuels produced from biological systems should be chemically similar to petroleum, like fatty-acid-based molecules including free fatty acids, fatty acid methyl esters, fatty acid ethyl esters, fatty alcohols and fatty alkanes. This study founded a gas chromatography-mass spectrometry (GC-MS) method for simultaneous quantification of seven free fatty acids, nine fatty acid methyl esters, five fatty acid ethyl esters, five fatty alcohols and three fatty alkanes produced by wild-type Synechocystis PCC 6803 and its genetically engineered strain. Data obtained from GC-MS analyses were quantified using internal standard peak area comparisons. The linearity, limit of detection (LOD) and precision (RSD) of the method were evaluated. The results demonstrated that fatty-acid-based biofuels can be directly determined by GC-MS without derivation. Therefore, rapid and reliable quantitative analysis of fatty-acid-based biofuels produced by wild-type and genetically engineered cyanobacteria can be achieved using the GC-MS method founded in this work.

  14. [Novel method for the identification of illegal cooking oil (2) : determination of special odd-chain fatty acids by multidimensional gas chromatography-mass spectrometry].

    Science.gov (United States)

    Jin, Jing; Wang, Longxing; Chen, Jiping; Tian, Yuzeng; Zou, Lili; Zhang, Baoqin; Wang, Shuqiu; Wang, Xingfu

    2012-11-01

    Endogenesis referents from illegal cooking oil (ICO), namely, 13-methyl-tetradecanoic acid and undecanoic acid have been confirmed via non-target and target screening of fatty acids. The former is mainly originated from animal oil, and the later from heated vegetable oil. Based on the retention interactions between gas chromatographic columns with different polarities and alkyl acids, the alkyl acids with various carbon chain or their isomers with the same carbon chains can be separated effectively using multidimensional gas chromatographymass spectrometry. And the accurate quantification of 13-methyl-tetradecanoic acid and undecanoic acid was obtained. The target compounds can be cleaned up online and enriched with the developed method. Subsequently, the fourth and fifth assessments organized by China National Center for Food Safety Risk Assessment were performed in our laboratory. After continuous improvement, the precision of the method was increased. In detail, 100% vegetable oils, 71% ICO (the 4th batch) and 75% ICO (the 5th batch) have been identified. In combination with the capsaicinoid contents, edible oils can be identified in a comprehensive way, and the precision for ICO samples was increased to 89% and 100% for the 4th batch and the 5th batch samples, respectively. Owing to the aforementioned advantages, the developed method has been chosen as one of the four instrumental methods for the identification of ICO by China Ministry of Public Health, waiting for the validation from authoritative departments.

  15. POPs as hazardous waste and appearance in the industry

    OpenAIRE

    Alili, Agron; Karakaseva, Snezana; Krstev, Boris; Krstev, Aleksandar

    2014-01-01

    Hazardous waste is waste, which is consist from composition or concentration of hazardous substances which can cause hazards on environmental and people health and have one or more hazardous properties, such as explosive, reactive (oxidizing), flammability, irritability, toxicity, infectivity, carcinogenicity, mutagenicity, reproduction toxicity, ecotoxicity and discharge properties of toxic gases in contact with water, air od acid, determined in accordance with this law or other regulatin, w...

  16. Efficient carbon dioxide utilization and simultaneous hydrogen enrichment from off-gas of acetone-butanol-ethanol fermentation by succinic acid producing Escherichia coli.

    Science.gov (United States)

    He, Aiyong; Kong, Xiangping; Wang, Chao; Wu, Hao; Jiang, Min; Ma, Jiangfeng; Ouyang, Pingkai

    2016-08-01

    The off-gas from acetone-butanol-ethanol (ABE) fermentation was firstly used to be CO2 source (co-substrate) for succinic acid production. The optimum ratio of H2/CO2 indicated higher CO2 partial pressures with presence of H2 could enhance C4 pathway flux and reductive product productivity. Moreover, when an inner recycling bioreactor was used for CO2 recycling at a high total pressure (0.2Mpa), a maximum succinic acid concentration of 65.7g·L(-1) was obtained, and a productivity of 0.76g·L(-1)·h(-1) and a high yield of 0.86g·g(-1) glucose were achieved. Furthermore, the hydrogen content was simultaneously enriched to 92.7%. These results showed one successful attempt to reuse the off-gas of ABE fermentation which can be an attractive CO2 source for succinic acid production.

  17. Determination of the Content of Acrolein, Acetic Acid and Acrylic Acid in Tail Gas from Acrylic Acid Production of Propylene Oxidation by Gas Chromatography%气相色谱法测定丙烯氧化生产丙烯酸尾气中丙烯醛、乙酸、丙烯酸含量

    Institute of Scientific and Technical Information of China (English)

    陈科杰

    2013-01-01

    采用毛细管气相色谱法测定丙烯氧化生产丙烯酸尾气中丙烯醛、乙酸、丙烯酸的含量,色谱柱为FFAP(30 m×0.53 mm,1μm),检测器为FID,用外标法进行定量,尾气样品中丙烯醛、乙酸、丙烯酸的检出限分别为0.025,0.033,0.031 mg/m3,测定结果的相对偏差为0.97%~2.63%(n=5),加标回收率为98.29%~103.60%。%The content of acrolein, acetic acid and acrylic acid in tail gas from acrylic acid produection of propylene oxidation was determined by capillary gas chronmatography with FFAP column (30 m×0.53 mm,1 µm), FID as the detector and external standard as the quantitative method. The detection limits of 3 components in tail gas were 0.025, 0.033 and 0.031 mg/m3, respectively. The relative standard deviation was 0.97%-2.63%(n=5), and the recoveries were 98.29%-103.60%.

  18. Rapid analysis of fatty acid profiles in raw nuts and seeds by microwave-ultrasonic synergistic in situ extraction-derivatisation and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Liu, Rui-Lin; Song, Shuang-Hong; Wu, Mei; He, Tian; Zhang, Zhi-Qi

    2013-12-15

    Based on microwave-ultrasonic synergistic in situ extraction-derivatisation (MUED), gas chromatography-mass spectrometry was proposed for rapid analysis of fatty acid profiles in raw nut and seed materials. Several critical experimental parameters for MUED, including reaction temperature, microwave power, amounts of catalyst and derivatisation reagent, have been optimised using response surface methodology. The results showed that the chromatographic peak areas of total fatty acids and the content of total unsaturated fatty acids obtained with MUED were markedly higher than those obtained by the conventional method (P<0.05 and P<0.01, respectively). The MUED method simplified the handling steps compared to the conventional procedure, shortened the sample preparation time whilst improving the extraction and derivatisation efficiency of lipids, and reduced oxidisation and decomposition of the unsaturated fatty acids. The simplicity, robustness and practicality of this method highlighted its significant potential for application in the rapid analysis of fatty acids in natural food resource samples.

  19. Semi-continuous measurements of gas/particle partitioning of organic acids in a ponderosa pine forest using a MOVI-HRToF-CIMS

    Directory of Open Access Journals (Sweden)

    R. L. N. Yatavelli

    2013-06-01

    Full Text Available Hundreds of gas and particle phase organic acids were measured in a rural ponderosa pine forest in Colorado, USA, during the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen – Rocky Mountain Biogenic Aerosol Study (BEACHON-RoMBAS. A recently developed Micro-Orifice Volatilization Impactor High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (MOVI-HRToF-CIMS using acetate (CH3C(OO- as the reagent ion was used to selectively ionize and detect acids semi-continuously from 20–30 August 2011, with a measurement time resolution of ~1.5 h. At this site 98% of the organic acid mass is estimated to be in the gas-phase, with only ~2% in the particle phase. We investigated gas/particle partitioning, quantified as the fraction in the particle phase (Fp, of C1–C18 alkanoic acids, six known terpenoic acids and total bulk organic acids. Data were compared to the absorptive partitioning model and suggest that bulk organic acids at this site follow absorptive partitioning to the organic aerosol mass. The rapid response (<1–2 h of partitioning to temperature changes for bulk acids suggests that kinetic limitations to equilibrium are minor, which is in contrast to conclusions of some recent laboratory and field studies, possibly due to lack of very low ambient relative humidities at this site. Time trends for partitioning of individual and groups of acids were mostly captured by the model, with varying degrees of absolute agreement. Species with predicted substantial fractions in both the gas and particle phases show better absolute agreement, while species with very low predicted fractions in one phase often show agreement on trends, but poor absolute agreement, potentially due to thermal decomposition, inlet adsorption, or other issues. Based on measurement-model comparison we conclude that species carbon number and oxygen content, together with ambient temperature control the volatility of organic

  20. Semi-continuous measurements of gas/particle partitioning of organic acids in a ponderosa pine forest using a MOVI-HRToF-CIMS

    Science.gov (United States)

    Yatavelli, R. L. N.; Stark, H.; Thompson, S. L.; Kimmel, J. R.; Cubison, M. J.; Day, D. A.; Campuzano-Jost, P.; Palm, B. B.; Thornton, J. A.; Jayne, J. T.; Worsnop, D. R.; Jimenez, J. L.

    2013-06-01

    Hundreds of gas and particle phase organic acids were measured in a rural ponderosa pine forest in Colorado, USA, during the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen - Rocky Mountain Biogenic Aerosol Study (BEACHON-RoMBAS). A recently developed Micro-Orifice Volatilization Impactor High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (MOVI-HRToF-CIMS) using acetate (CH3C(O)O-) as the reagent ion was used to selectively ionize and detect acids semi-continuously from 20-30 August 2011, with a measurement time resolution of ~1.5 h. At this site 98% of the organic acid mass is estimated to be in the gas-phase, with only ~2% in the particle phase. We investigated gas/particle partitioning, quantified as the fraction in the particle phase (Fp), of C1-C18 alkanoic acids, six known terpenoic acids and total bulk organic acids. Data were compared to the absorptive partitioning model and suggest that bulk organic acids at this site follow absorptive partitioning to the organic aerosol mass. The rapid response (<1-2 h) of partitioning to temperature changes for bulk acids suggests that kinetic limitations to equilibrium are minor, which is in contrast to conclusions of some recent laboratory and field studies, possibly due to lack of very low ambient relative humidities at this site. Time trends for partitioning of individual and groups of acids were mostly captured by the model, with varying degrees of absolute agreement. Species with predicted substantial fractions in both the gas and particle phases show better absolute agreement, while species with very low predicted fractions in one phase often show agreement on trends, but poor absolute agreement, potentially due to thermal decomposition, inlet adsorption, or other issues. Based on measurement-model comparison we conclude that species carbon number and oxygen content, together with ambient temperature control the volatility of organic acids and are good

  1. The Contribution of the Activation Entropy to the Gas-Phase Stability of Modified Nucleic Acid Duplexes

    Science.gov (United States)

    Hari, Yvonne; Dugovič, Branislav; Istrate, Alena; Fignolé, Annabel; Leumann, Christian J.; Schürch, Stefan

    2016-07-01

    Tricyclo-DNA (tcDNA) is a sugar-modified analogue of DNA currently tested for the treatment of Duchenne muscular dystrophy in an antisense approach. Tandem mass spectrometry plays a key role in modern medical diagnostics and has become a widespread technique for the structure elucidation and quantification of antisense oligonucleotides. Herein, mechanistic aspects of the fragmentation of tcDNA are discussed, which lay the basis for reliable sequencing and quantification of the antisense oligonucleotide. Excellent selectivity of tcDNA for complementary RNA is demonstrated in direct competition experiments. Moreover, the kinetic stability and fragmentation pattern of matched and mismatched tcDNA heteroduplexes were investigated and compared with non-modified DNA and RNA duplexes. Although the separation of the constituting strands is the entropy-favored fragmentation pathway of all nucleic acid duplexes, it was found to be only a minor pathway of tcDNA duplexes. The modified hybrid duplexes preferentially undergo neutral base loss and backbone cleavage. This difference is due to the low activation entropy for the strand dissociation of modified duplexes that arises from the conformational constraint of the tc-sugar-moiety. The low activation entropy results in a relatively high free activation enthalpy for the dissociation comparable to the free activation enthalpy of the alternative reaction pathway, the release of a nucleobase. The gas-phase behavior of tcDNA duplexes illustrates the impact of the activation entropy on the fragmentation kinetics and suggests that tandem mass spectrometric experiments are not suited to determine the relative stability of different types of nucleic acid duplexes.

  2. Discussion about the Hazards and Preventive Measures of Cine Film Acetic Acid Syndrome%浅谈电影胶片醋酸综合症的危害及其预防措施

    Institute of Scientific and Technical Information of China (English)

    周亚军; 李玉虎

    2011-01-01

    The cine film, as a kind of important historical and cultural heritage, is an important part of the archives protection works. The cellulose triacetate base cinefilm is the largest group in library collections, the acetic acid syndromes is produced from the hydrolysis of the cellulose triacetate ester base film under the storage condition of high temperature and humidity and other adverse environment. Acetic acid syndrome has become the major diseases which threaten the archives preservation of cellulose triacetate cine film, which is considered the cancer of cine film. This paper summarizes the hazards and analyses the reasons of acetic acid syndrome, and preventive measures are introduced.%电影胶片是一类重要的历史文化遗产,也是国家档案保存的重要组成部分.三醋酸纤维素酯电影胶片是馆藏最多的一类影片,然而其片基构成材料三醋酸纤维素酯水解而产生的醋酸综合症是危害其安全存贮的主要病害,被称为电影胶片的“癌症”.本文分析了醋酸综合症产生的原因,介绍了醋酸综合症的危害及预防电影胶片发生醋酸综合症的措施.

  3. Study of polyaniline doped with trifluoromethane sulfonic acid in gas-diffusion electrodes for proton-exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Gharibi, Hussein; Zhiani, Mohammad; Kheirmand, Mehdi; Kakaei, Karim [Department of Physical Chemistry, Faculty of Science, Tarbiat Modarres University, P.O. Box 14115-175, Tehran (Iran); Entezami, Ali Akbar [Faculty of Chemistry, Tabriz University, Tabriz (Iran); Mirzaie, Rasol Abdullah [Department of Chemistry, Faculty of Science, Shahid Rajaee University, Tehran (Iran)

    2006-04-21

    Polytetrafluoroethylene (PTFE)-bonded gas-diffusion electrodes (GDEs), modified with polyaniline as an electron and proton conductor in the catalyst layer, are prepared and evaluated for use in proton-exchange membrane fuel cells (PEMFCs). Polyaniline is coated on the GDE by electropolymerization of aniline and trifluoromethane sulfonic acid as the proton-conductive monomer. The electrodes are characterized by cyclic voltammetry, current-potential measurements, electrochemical impedance spectroscopy, and chronoamperometry. The polyaniline is found to be homogenously dispersed in the catalyst layer, making it a good candidate proton and electron conductor. Use of polyaniline instead of Nafion in the catalyst layer, increases the utility of the electrocatalyst by 18%. The results are consistent with the presence of polyaniline as a conductive polymer in the reaction layer reducing the polarization resistance of the electrode in comparison with that of a corresponding electrode containing Nafion. Thus, the present results indicate that PEMFCs using polyaniline-containing electrocatalysts should give superior performance to those using catalysts containing traditional ionomers. (author)

  4. Development of Monopole Interaction Models for Ionic Compounds. Part I: Estimation of Aqueous Henry's Law Constants for Ions and Gas Phase pKa Values for Acidic Compounds.

    Science.gov (United States)

    Hilal, S H; Saravanaraj, A N; Carreira, L A

    2014-02-01

    The SPARC (SPARC Performs Automated Reasoning in Chemistry) physicochemical mechanistic models for neutral compounds have been extended to estimate Henry's Law Constant (HLC) for charged species by incorporating ionic electrostatic interaction models. Combinations of absolute aqueous pKa values, relative pKa values in the gas phase, and aqueous HLC for neutral compounds have been used to develop monopole interaction models that quantify the energy differences upon moving an ionic solute molecule from the gas phase to the liquid phase. Inter-molecular interaction energies were factored into mechanistic contributions of monopoles with polarizability, dipole, H-bonding, and resonance. The monopole ionic models were validated by a wide range of measured gas phase pKa data for 450 acidic compounds. The RMS deviation error and R(2) for the OH, SH, CO2 H, CH3 and NR2 acidic reaction centers (C) were 16.9 kcal/mol and 0.87, respectively. The calculated HLCs of ions were compared to the HLCs of 142 ions calculated by quantum mechanics. Effects of inter-molecular interaction of the monopoles with polarizability, dipole, H-bonding, and resonance on acidity of the solutes in the gas phase are discussed.

  5. 75 FR 53371 - Liquefied Natural Gas Facilities: Obtaining Approval of Alternative Vapor-Gas Dispersion Models

    Science.gov (United States)

    2010-08-31

    ... Pipeline and Hazardous Materials Safety Administration Liquefied Natural Gas Facilities: Obtaining Approval... Safety Administration (PHMSA) issues federal safety standards for siting liquefied natural gas (LNG...) NFPA 59A: Standard for the Production, Storage, and Handling of Liquefied Natural Gas. That...

  6. Household Hazardous Waste

    Science.gov (United States)

    Jump to main content US EPA United States Environmental Protection Agency Search Search Hazardous Waste Share Facebook Twitter ... risks associated with household hazardous wastes, it is important that people always monitor the use, storage, and ...

  7. Hazard Analysis Database Report

    CERN Document Server

    Grams, W H

    2000-01-01

    The Hazard Analysis Database was developed in conjunction with the hazard analysis activities conducted in accordance with DOE-STD-3009-94, Preparation Guide for U S . Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports, for HNF-SD-WM-SAR-067, Tank Farms Final Safety Analysis Report (FSAR). The FSAR is part of the approved Authorization Basis (AB) for the River Protection Project (RPP). This document describes, identifies, and defines the contents and structure of the Tank Farms FSAR Hazard Analysis Database and documents the configuration control changes made to the database. The Hazard Analysis Database contains the collection of information generated during the initial hazard evaluations and the subsequent hazard and accident analysis activities. The Hazard Analysis Database supports the preparation of Chapters 3 ,4 , and 5 of the Tank Farms FSAR and the Unreviewed Safety Question (USQ) process and consists of two major, interrelated data sets: (1) Hazard Analysis Database: Data from t...

  8. Introducing Environmental and Sustainable Chemistry Topics Using a Nanotechnology Approach: Removing Hazardous Metal Ions by Means of Humic-Acid-Modified Superparamagnetic Nanoparticles

    Science.gov (United States)

    Gomes da Silva, Delmarcio; Menegatti de Melo, Fernando; Silveira, Alceu Totti, Jr.; Constancio da Cruz, Bruno; Prado, Caio Cesar Pestana; Pereira de Vasconcelos, Luana Cristina; Lucas, Vitor Amaral Sanches; Toma, Henrique Eisi

    2016-01-01

    A laboratory experiment has been developed to illustrate environmental and sustainability aspects, focusing on the wastewater treatment by means of superparamagnetic nanoparticles functionalized with humic acid. The experiment, conducted by a group of high school students, involves nanoparticle synthesis and minor characterization, followed by…

  9. Analysis on structural response of FPSO subjected to deflagration hazard of leaking oil and gas%泄漏油气燃爆灾害下FPSO结构响应分析∗

    Institute of Scientific and Technical Information of China (English)

    李修峰; 陈国明; 师吉浩

    2015-01-01

    Given the high risk about structural damage of FPSO subjected to deflagration hazard resulted by leaking oil and gas, the structural dynamic response under blast wave was studied by combining equivalent TNT method and AUTODYN. The characteristics of elastic-plastic state, displacement and stress distribution of structure were ana-lyzed in details, and the degree of structural damage under different deflagration conditions was evaluated. The re-sults showed that the blast wave propagates around in high speed after TNT initiation, and it takes only 10 ms for blast wave to cover the whole area of processing module direct . The reflection of equipments and coupling superpo-sition effect enhances the destructive power of blast wave greatly. The crude oil thermal theater and electric clipper desalter are vulnerable to suffering the failure damage and whole displacement. The large displacement and plastic deformation occurs in edge region of process deck, and part of structure suffers buckling failure. The more oil and gas leaks, the greater equivalent stress and displacement of structure in same position are, and the wider regional distribution with large stress and displacement becomes. When the leakage aperture is 60 mm, some structure fail completely.%为评估FPSO泄漏油气燃爆事故中结构损伤风险,采用等效TNT法结合AUTODYN软件分析结构在爆炸冲击波下动态响应,分析其塑性、变形及应力分布,评估不同工况下结构损伤程度。结果表明,TNT起爆后冲击波高速传播,10ms时已覆盖工艺I区,经反射叠加耦合后破坏力增强;原油热处理器和电脱盐器发生失效和变形,生产甲板边缘位置受约束较小,发生较大变形,部分区域屈曲破坏;参与反应的油气越多,相同结构等效应力及变形越大,大应力、大变形区域分布越广;d=60mm时部分结构完全失效。

  10. Magnetohydrodynamics and its hazard assessment

    Science.gov (United States)

    Chan, W.-T.

    1981-11-01

    Potential occupational and environmental hazards of a typical combined open-cycle MHD/steam cycle power plant are critically assessed on the basis of direct/indirect research information. Among the potential occupational hazards, explosion at the coal feed system or at the superconducting magnet; combustor rupture in a confined pit; high intensity dc magnetic field exposure at the channel; and combustion products leakage from the pressurized systems are of primary concern. While environmental emissions of SO(x), NO(x) and fine particulates are considered under control in experimental scale, control effectiveness at high capacity operation remains uncertain. Gaseous emission of some highly toxic trace elements including radioactive species may be of concern without gas cleaning device in the MHD design.

  11. Hazard function theory for nonstationary natural hazards

    Science.gov (United States)

    Read, Laura K.; Vogel, Richard M.

    2016-04-01

    Impact from natural hazards is a shared global problem that causes tremendous loss of life and property, economic cost, and damage to the environment. Increasingly, many natural processes show evidence of nonstationary behavior including wind speeds, landslides, wildfires, precipitation, streamflow, sea levels, and earthquakes. Traditional probabilistic analysis of natural hazards based on peaks over threshold (POT) generally assumes stationarity in the magnitudes and arrivals of events, i.e., that the probability of exceedance of some critical event is constant through time. Given increasing evidence of trends in natural hazards, new methods are needed to characterize their probabilistic behavior. The well-developed field of hazard function analysis (HFA) is ideally suited to this problem because its primary goal is to describe changes in the exceedance probability of an event over time. HFA is widely used in medicine, manufacturing, actuarial statistics, reliability engineering, economics, and elsewhere. HFA provides a rich theory to relate the natural hazard event series (X) with its failure time series (T), enabling computation of corresponding average return periods, risk, and reliabilities associated with nonstationary event series. This work investigates the suitability of HFA to characterize nonstationary natural hazards whose POT magnitudes are assumed to follow the widely applied generalized Pareto model. We derive the hazard function for this case and demonstrate how metrics such as reliability and average return period are impacted by nonstationarity and discuss the implications for planning and design. Our theoretical analysis linking hazard random variable X with corresponding failure time series T should have application to a wide class of natural hazards with opportunities for future extensions.

  12. Volcanic hazards on the Island of Hawaii

    Science.gov (United States)

    Mullineaux, Donal Ray; Peterson, Donald W.

    1974-01-01

    Volcanic hazards on the Island of Hawaii have been determined to be chiefly products of eruptions: lava flows, falling fragments, gases, and particle-and-gas clouds. Falling fragments and particle-and-gas clouds can be substantial hazards to life, but they are relatively rare. Lava flows are the chief hazard to property; they are frequent and cover broad areas. Rupture, subsidence, earthquakes, and sea waves (tsunamis) caused by eruptions are minor hazards; those same events caused by large-scale crustal movements, however, are major hazards to both life and property. Volcanic hazards are greatest on Mauna Loa and Kilauea, and the risk is highest along the rift zones of those volcanoes. The hazards are progressively less severe on Hualalai, Mauna Kea, and Kohala volcanoes. Some risk from earthquakes extends across the entire island, and the risk from tsunamis is high all along the coast. The island has been divided into geographic zones of different relative risk for each volcanic hazard, and for all those hazards combined. Each zone is assigned a relative risk for that area as a whole; the degree of risk varies within the zones, however, and in some of them the risk decreases gradationally across the entire zone. Moreover, the risk in one zone may be locally as great or greater than that at some points in the zone of next higher overall risk. Nevertheless, the zones can be highly useful for land-use planning. Planning decisions to which the report is particularly applicable include the selection of kinds of structures and kinds of land use that are appropriate for the severity and types of hazards present. For example, construction of buildings that can resist a lava flow is generally not feasible, but it is both feasible and desirable to build structures that can resist falling rock fragments, earthquakes, and tsunamis in areas where risk from those hazards is relatively high. The report can also be used to select sites where overall risk is relatively low, to

  13. Synthesis of hydrophobic cross-linked polyzwitterionic acid for simultaneous sorption of Eriochrome black T and chromium ions from binary hazardous waters.

    Science.gov (United States)

    Saleh, Tawfik A; Muhammad, Auwal M; Ali, Shaikh A

    2016-04-15

    Hydrophobic cross-linked polyzwitterionic acid (HCPZA) containing long chain (C18) hydrophobes and residues of a glutamic acid having unquenched nitrogen valency was synthesized. Exploiting the chelating ability of the amino acid residues to scavenge toxic metals and the hydrophobic surface to scoop up the organic contaminants, the resin HCPZA was evaluated for simultaneous removal of chromium and Eriochrome black T (EBT) from wastewaters. The structure and morphology of the polymer before and after sorption were characterized by using FTIR, TGA, EDX and SEM. The effect of various parameters such as contact time, pH and initial concentrations were investigated to arrive at optimum conditions. The adsorption of Eriochrome black T and Cr (III) on HCPZA reached equilibrium in 30 min. The mechanism of adsorption was investigated using kinetic, diffusion and isotherm models. The adsorption kinetic data were described well by the pseudo-second order model and by the Freundlich isotherm model. EDX analysis confirmed the adsorption of Cr (III) and EBT on the polymer. The hydrophobic resin exhibited a remarkable simultaneous adsorption capacity for EBT and Cr (III) and thus demonstrated its potential to be a promising adsorbent for removal of dyes and heavy metal ions from wastewaters.

  14. Temperature and acidity effects on WO{sub 3} nanostructures and gas-sensing properties of WO{sub 3} nanoplates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Huili [School of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin 300384 (China); Liu, Zhifang; Yang, Jiaqin; Guo, Wei [Department of Materials Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (MOE), TKL of Metal and Molecule-based Material Chemistry, Synergetic Innovation Centre of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071 (China); Zhu, Lianjie, E-mail: zhulj@tjut.edu.cn [School of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin 300384 (China); Zheng, Wenjun, E-mail: zhwj@nankai.edu.cn [Department of Materials Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (MOE), TKL of Metal and Molecule-based Material Chemistry, Synergetic Innovation Centre of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071 (China)

    2014-09-15

    Graphical abstract: Generally, large acid quantity and high temperature are beneficial to the formation of anhydrous WO3, but the acidity effect on the crystal phase is weaker than that of temperature. Large acid quantity is found helpful to the oriented growth of tungsten oxides, forming a nanoplate-like product. - Highlights: • Large acid quantity is propitious to the oriented growth of a WO{sub 3} nanoplate. • Effect of acid quantity on crystal phases of products is weaker than that of temperature. • One step hydrothermal synthesis of WO{sub 3} is facile and can be easily scaled up. • A WO{sub 3} nanoplate shows a fast response and distinct sensing selectivity to acetone gas. - Abstract: WO{sub 3} nanostructures were successfully synthesized by a facile hydrothermal method using Na{sub 2}WO{sub 4}·2H{sub 2}O and HNO{sub 3} as raw materials. They are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The specific surface area was obtained from N{sub 2} adsorption–desorption isotherm. The effects of the amount of HNO{sub 3}, hydrothermal temperature and reaction time on the crystal phases and morphologies of the WO{sub 3} nanostructures were investigated in detail, and the reaction mechanism was discussed. Large amount of acid is found for the first time to be helpful to the oriented growth of tungsten oxides, forming nanoplate-like products, while hydrothermal temperature has more influence on the crystal phase of the product. Gas-sensing properties of the series of as-prepared WO{sub 3} nanoplates were tested by means of acetone, ethanol, formaldehyde and ammonia. One of the WO{sub 3} nanoplates with high specific surface area and high crystallinity displays high sensitivity, fast response and distinct sensing selectivity to acetone gas.

  15. Prevalence of hazardous exposures in veterinary practice

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, P.; Schenker, M.B.; Green, R.; Samuels, S.

    1989-01-01

    All female graduates of a major U.S. veterinary school were surveyed by mailed questionnaire to obtain details of work practice and hazard exposure during the most recent year worked and during all pregnancies. Exposure questions were based on previously implicated occupational hazards which included anesthetic gases, radiation, zoonoses, prostaglandins, vaccines, physical trauma, and pesticides. The response rate was 86% (462/537). We found that practice type and pregnancy status were major determinants of hazard exposure within the veterinary profession. Small-animal practitioners reported the highest rates of exposure to anesthetic gas (94%), X-ray (90%), and pesticides (57%). Large-animal practitioners reported greater rates of trauma (64%) and potential exposure to prostaglandins (92%), Brucella abortus vaccine (23%), and carbon monoxide (18%). Potentially hazardous workplace practices or equipment were common. Forty-one percent of respondents who reported taking X-rays did not wear film badges, and 76% reported physically restraining animals for X-ray procedures. Twenty-seven percent of the respondents exposed to anesthetic gases worked at facilities which did not have waste anesthetic gas scavenging systems. Women who worked as veterinarians during a pregnancy attempted to reduce exposures to X-rays, insecticides, and other potentially hazardous exposures. Some potentially hazardous workplace exposures are common in veterinary practice, and measures to educate workers and to reduce these exposures should not await demonstration of adverse health effects.

  16. Influence of Smelting-Flue-Gas-Sulfuric Acid Purifying Process to Reagent Sulfuric Acid Preparation%冶炼烟气硫酸净化工艺对制取试剂硫酸的影响研究

    Institute of Scientific and Technical Information of China (English)

    张析; 余江鸿; 王进龙

    2014-01-01

    s:By using smelting-flue-gas sulfuric acid from a lead-zinc smelter as raw material to prepare reagent sulfuric acid through the process of direct distillation , it has heavy impact on quality of the reagent acid due to that lab test shows high content of impurities in the raw material acid .Therefore, raw material acid should be purified before distillatio , and experi-mental test is carried out to study raw material acid purifying process .Reagent sulfuric acid prepared from purified raw ma-terial acid meet the specifications for Chemically Pure under the National Standard GB /T625-2007.%利用某铅锌冶炼厂冶炼烟气硫酸为原料,经分析化验,原料酸中杂质含量较高,直接蒸馏对试剂硫酸的质量影响较大。因此,在蒸馏前需对原料酸进行净化处理,对原料酸的净化工艺进行了试验研究,采用经过净化的原料酸制取的试剂硫酸产品指标达到国家标准GB/T625-2007化学纯指标要求。

  17. Use of solid-phase microextraction for the detection of acetic acid by ion-trap gas chromatography-mass spectrometry and application to indoor levels in museums.

    Science.gov (United States)

    Godoi, Ana F L; Van Vaeck, Luc; Van Grieken, René

    2005-03-01

    A simple and efficient method using solid-phase microextraction (SPME) and gas chromatography-ion trap mass spectrometry (GC-ITMS) was developed for the analysis of acetic acid in air. The choice of the SPME fibre revealed to be critical as well as the sampling and desorption time. A dilution vessel was used for calibration. The precision of the method was found to be 4.7% relative standard deviation (RSD) and the detection limit 5.7 microg m(-3). The SPME-GC-MS technique was applied to the analysis of acetic acid in museum atmospheres.

  18. Effect of flue gas CO2 on the growth, carbohydrate and fatty acid composition of a green microalga Scenedesmus obliquus for biofuel production.

    Science.gov (United States)

    Ji, Min-Kyu; Yun, Hyun-Shik; Hwang, Jae-Hoon; Salama, El-Sayed; Jeon, Byong-Hun; Choi, Jaeyoung

    2016-10-31

    Effect of various flue gas CO2 concentrations (5%, 10% and 14.1%) on growth rate and biochemical properties of a green microalga Scenedesmus obliquus was investigated. S. obliquus showed the highest biomass production and growth rate (0.36 g L(-1) and μmax = 1.00 day(-1)), total inorganic carbon removal (35.8 mg L(-1)), lipid productivity (9.9 mg L(-1) day) and carbohydrate productivity (10.3 mg L(-1) day) with 14.1% CO2 after 8 days of cultivation. Fatty acid methyl ester analysis revealed that the palmitic and oleic acid contents were increased up to 5% and 7% with 14.1% CO2, respectively. Application of flue gas CO2 enhanced the growth along with lipid and carbohydrate productivity of S. obliquus, which can be exploited for reducing the CO2 concentration.

  19. Effects of phosphoric acid sprayed into an incinerator furnace on the flue gas pressure drop at fabric filters.

    Science.gov (United States)

    Takahashi, Shigetoshi; Hwang, In-Hee; Matsuto, Toshihiko

    2016-06-01

    Fabric filters are widely used to remove dust from flue gas generated by waste incineration. However, a pressure drop occurs at the filters, caused by growth of a dust layer on the filter fabric despite regular cleaning by pulsed-jet air. The pressure drop at the fabric filters leads to energy consumption at induced draft fan to keep the incinerator on negative pressure, so that its proper control is important to operate incineration facility efficiently. The pressure drop at fabric filters decreased whenever phosphoric acid wastewater (PAW) was sprayed into an incinerator for treating industrial waste. Operational data obtained from the incineration facility were analyzed to determine the short- and long-term effects of PAW spraying on the pressure drop. For the short-term effect, it was confirmed that the pressure drop at the fabric filters always decreased to 0.3-1.2kPa within about 5h after spraying PAW. This effect was expected to be obtained by about one third of present PAW spraying amount. However, from the long-term perspective, the pressure drop showed an increase in the periods of PAW spraying compared with periods for which PAW spraying was not performed. The pressure drop increase was particularly noticeable after the initial PAW spraying, regardless of the age and type of fabric filters used. These results suggest that present PAW spraying causes a temporary pressure drop reduction, leading to short-term energy consumption savings; however, it also causes an increase of the pressure drop over the long-term, degrading the overall operating conditions. Thus, appropriate PAW spraying conditions are needed to make effective use of PAW to reduce the pressure drop at fabric filters from a short- and long-term point of view.

  20. Development of a gas-liquid chromatographic method for the analysis of fatty acid tryptamides in cocoa products.

    Science.gov (United States)

    Hug, Bernadette; Golay, Pierre-Alain; Giuffrida, Francesca; Dionisi, Fabiola; Destaillats, Frédéric

    2006-05-03

    The determination of the occurrence and level of cocoa shells in cocoa products and chocolate is an important analytical issue. The recent European Union directive on cocoa and chocolate products (2000/36/EC) has not retained the former limit of a maximum amount of 5% of cocoa shells in cocoa nibs (based on fat-free dry matter), previously authorized for the elaboration of cocoa products such as cocoa mass. In the present study, we report a reliable gas-liquid chromatography procedure suitable for the determination of the occurrence of cocoa shells in cocoa products by detection of fatty acid tryptamides (FATs). The precision of the method was evaluated by analyzing nine different samples (cocoa liquors with different ranges of shells) six times (replicate repeatability). The variations of the robust coefficient of variation of the repeatability demonstrated that FAT(C22), FAT(C24), and total FATs are good markers for the detection of shells in cocoa products. The trueness of the method was evaluated by determining the FAT content in two spiked matrices (cocoa liquors and cocoa shells) at different levels (from 1 to 50 mg/100 g). A good relation was found between the results obtained and the spiking (recovery varied between 90 and 130%), and the linearity range was established between 1 and 50 mg/100 g in cocoa products. For total FAT contents of cocoa liquor containing 5% shells, the measurement uncertainty allows us to conclude that FAT is equal to 4.01 +/- 0.8 mg/100 g. This validated method is perfectly suitable to determine shell contents in cocoa products using FAT(C22), FAT(C24), and total FATs as markers. The results also confirmed that cocoa shells contain FAT(C24) and FAT(C22) in a constant ratio of nearly 2:1.

  1. 鲁奇低温甲醇洗酸气提浓的操作优化%Operational Optimization Increasing Concentration of Acidic Gas in Lurgi Rectisol Plant

    Institute of Scientific and Technical Information of China (English)

    张成祥; 张先春; 宋淑群

    2014-01-01

    针对兖矿国宏化工有限责任公司50万t/a甲醇项目鲁奇低温甲醇洗装置酸气浓度较低的问题,依据德国鲁奇公司提供的低温甲醇洗物料平衡表,对热再生塔和甲醇水分离塔进行了物料平衡计算。计算结果表明,CO2浓度为65.682%,降低CO2含量可提高酸气浓度,故采取了关闭预洗甲醇调节阀、提高酸气浓度的操作方法,使酸气中H2 S浓度由32%上升至44%。%In allusion to problem that the concentration of acid gas is relatively lower in the Lurgi Rectisol plant of methanol project with a capacity of 500 000 t/a in the Yankuang Guohong Chemical Engineering Company Ltd. , material based on material balance list of Rectisol plant, provided by German Lurgi Company, material balance calculation was made for the heat regeneration tower and methanol water separation tower. Calculating result indicates that CO2 concentration is 65. 682%, decreasing CO2 content can increase the acid gas concentration, therefore adopting these operating methods, such as closing the adjusting valve for prewashing methanol and increasing acid gas concentration, that can make increasing the H2 S of acid gas concentration from 32% to 44%.

  2. 反式脂肪酸的危害及检测方法进展%Progress on Hazard and Detection Methods of Trans Fatty Acids

    Institute of Scientific and Technical Information of China (English)

    陈立奇; 晏立新

    2011-01-01

    @@ 反式脂肪酸(Trans Fatty Acids,TFA)也叫人造脂肪,是将植物油中的不饱和脂肪酸经过催化、加氢,使不饱和脂肪酸的结构发生变化,变成反式脂肪酸.随着科学的进步和人们生活水平的提高,以往传统的食品加工方法以及由此而产生的一些食品安全问题,不断引起人们的疑虑.

  3. Preliminary Study on the Effect of Ethylene Diamine- n, n-diacetic Acid on Methane Gas Production Rate from Cow Manure

    Directory of Open Access Journals (Sweden)

    Nwokem N Calvin

    2014-09-01

    Full Text Available In an effort to improve methane gas production rate from cattle slurry; ethylene diamine- N, N-diacetic acid chelating ligand was introduced into the digester system. Experimental analysis involving the determination of trace metals, pH and methane gas yield, were carried out with the use of the Flame Atomic Absorption Spectrophotometer and Biogas5000 analyser. The results showed that there was an increase in the pH of the system; the amount of methane gas yield equally increased by 12% and the Hydraulic Retention Time decreased from 50 days to 25 days on addition of ethylene diamine- N, N-diacetic acid chelating ligand. Also, increasing the concentration of the chelating ligand further decreased the HRT of the digester system from 25 days to 19days. Concentration of trace metals like Iron, Cobalt and Nickel within the digester system ranged from 0.001-0.050 mg/L; these metals reacted with ethylene diamine- N, N-diacetic acid chelating ligand to form metal chelates. The metal chelate formed resulted in the catalysis of the hydrolysis stage (which is the rate determining step of the anaerobic digestion process. Thus, the decrease in HRT was due to the metal chelate catalysis of the hydrolysis stage of the anaerobic digestion process were the metal chelate formation served as the driving force in the solvolysis process.

  4. High-resolution gas chromatography/mass spectrometry method for characterization and quantitative analysis of ginkgolic acids in Ginkgo biloba plants, extracts, and dietary supplements.

    Science.gov (United States)

    Wang, Mei; Zhao, Jianping; Avula, Bharathi; Wang, Yan-Hong; Avonto, Cristina; Chittiboyina, Amar G; Wylie, Philip L; Parcher, Jon F; Khan, Ikhlas A

    2014-12-17

    A high-resolution gas chromatography/mass spectrometry (GC/MS) with selected ion monitor method focusing on the characterization and quantitative analysis of ginkgolic acids (GAs) in Ginkgo biloba L. plant materials, extracts, and commercial products was developed and validated. The method involved sample extraction with (1:1) methanol and 10% formic acid, liquid-liquid extraction with n-hexane, and derivatization with trimethylsulfonium hydroxide (TMSH). Separation of two saturated (C13:0 and C15:0) and six unsaturated ginkgolic acid methyl esters with different positional double bonds (C15:1 Δ8 and Δ10, C17:1 Δ8, Δ10, and Δ12, and C17:2) was achieved on a very polar (88% cyanopropyl) aryl-polysiloxane HP-88 capillary GC column. The double bond positions in the GAs were determined by ozonolysis. The developed GC/MS method was validated according to ICH guidelines, and the quantitation results were verified by comparison with a standard high-performance liquid chromatography method. Nineteen G. biloba authenticated and commercial plant samples and 21 dietary supplements purported to contain G. biloba leaf extracts were analyzed. Finally, the presence of the marker compounds, terpene trilactones and flavonol glycosides for Ginkgo biloba in the dietary supplements was determined by UHPLC/MS and used to confirm the presence of G. biloba leaf extracts in all of the botanical dietary supplements.

  5. Liquid-liquid extraction of Cd(II) from pure and Ni/Cd acidic chloride media using Cyanex 921: a selective treatment of hazardous leachate of spent Ni-Cd batteries.

    Science.gov (United States)

    Choi, Seon-Young; Nguyen, Viet Tu; Lee, Jae-Chun; Kang, Ho; Pandey, B D

    2014-08-15

    The present paper is focused on solvent extraction of hazardous Cd(II) from acidic chloride media by Cyanex 921, a new extractant mixed with 10% (v/v) TBP in xylene. The optimum conditions for extraction and stripping of Cd(II) were investigated with an aqueous feed of 0.1 mol/L Cd(II) in 2.0 mol/L HCl. McCabe-Thiele diagram was in good agreement with the simulation studies, showing the quantitative extraction (99.9%) of Cd(II) within two counter-current stages utilizing 0.30 mol/L Cyanex 921 at O/A ratio of 3/2 in 10 min. Stoichiometry of the complexes extracted was determined and confirmed by numerical treatment and graphical method, revealing the formation of HCdCl3 · 2L and HCdCl3 · 4L for Cyanex 921(L) concentration in the range 0.03-0.1 mol/L and 0.1-1.0 mol/L, respectively. The thermodynamic parameters for the extraction of cadmium were also determined. The stripping efficiency of cadmium from the loaded organic with 0.10 mol/L HCl was 99.6% in a three-stage counter-current process at an O/A ratio of 2/3. Cyanex 921 was successfully applied for the separation of Cd(II) from Ni(II) in the simulated leach liquor of spent Ni-Cd batteries. The study demonstrates the applicability of the present hydrometallurgical approach for the treatment of hazardous waste, the spent Ni-Cd batteries.

  6. Simultaneous Determination of Melamine, Ammelide, Ammeline, and Cyanuric Acid in Milk and Milk Products by Gas Chromatography-tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    HONG MIAO; SAI FAN; YONG-NING WU; LEI ZHANG; PING-PING ZHOU; JING-GUANG LI; HUI-JING CHEN; YUN-FENG ZHAO

    2009-01-01

    Objective To develop an analytical method for simultaneously qualitative and quantitative determination of melamine and triazine-related by-products including ammelide, ammeline, and cyanuric acid in milk and milk products by gas chromatography-tandem mass spectrometry (GC-MS/MS). Methods Melamine and triazine-related by-products namely ammelide, ammeline and cyanuric acid in the samples were extracted in a solvent mixture of diethylamine, water, and acetonitrile (10:40:50, V/V/V). After centrifugation, an aliquot of the supernatant was evaporated to dryness under a gentle stream of nitrogen gas, and then melamine and triazine-related by-products were derivatized using BSTFA with 1% TMCS. The derivatives of melamine and its analogues were determined by gas chromatography/ tandem mass spectrometry using multiple reactional monitoring (MRM) with 2, 6-Diamino-4-chloropyrimidine (DACP) being used as an internal standard. Results The linear detectable ranges were from 0.004 mg/kg to 1.6 mg/kg for melamine, ammelide, ammeline, and cyanuric acid with a correlation coefficient no less than 0.999. The recovery rates of the four compounds in spiked blank milk powder at concentrations 0.5, 1, 2 mg/kg were between 61.4%-117.2%, and the relative standard deviation was no more than 11.5% (n=6). The detection limits of melamine, ammelide, ammeline and cyanuric acid in milk powder were 0.002 mg/kg with a ratio of signal to noise of 3. Conclusion This GC-MS/MS method for simultaneous determination of melamine, ammelide, ammeline, and cyanuric acid in milk and milk products is sensitive and specific.

  7. Hydrogen Oxidation on Gas Diffusion Electrodes for Phosphoric Acid Fuel Cells in the Presence of Carbon Monoxide and Oxygen

    DEFF Research Database (Denmark)

    Gang, Xiao; Li, Qingfeng; Hjuler, Hans Aage;

    1995-01-01

    Hydrogen oxidation has been studied on a carbon-supported platinum gas diffusion electrode in a phosphoric acidelectrolyte in the presence of carbon monoxide and oxygen in the feed gas. The poisoning effect of carbon monoxide presentin the feed gas was measured in the temperature range from 80...... to 150°C. It was found that throughout the temperaturerange, the potential loss due to the CO poisoning can be reduced to a great extent by the injection of small amounts ofgaseous oxygen into the hydrogen gas containing carbon monoxide. By adding 5 volume percent (v/o) oxygen, an almost...

  8. Rapid analysis of phthalic acid esters in environmental water using fast elution gas chromatography with mass spectrometry and adaptive library spectra.

    Science.gov (United States)

    Li, Pao; Mei, Zhen; Cai, Wensheng; Shao, Xueguang

    2014-07-01

    A method for the fast determination of the components in a complex sample by using gas chromatography with mass spectrometry was developed and used for the quantitative analysis of phthalic acid esters in environmental water. In the method, the adaptively corrected mass spectra were used to compensate for the differences between the library spectra and the measured ones in the experiment. The correction was obtained by the iterative transformation of the library spectra using iterative target transformation factor analysis, and the resolution was performed by non-negative immune algorithm using the corrected spectra. Rapid analysis of 16 phthalic acid esters in water samples was achieved using fast elution gas chromatography with mass spectrometry measurements. The results show that the mass spectra and chromatographic profiles of the phthalic acid esters can be obtained from the overlapping signal of 13 min elution, and accurate quantitative analysis can be obtained. The recoveries of the phthalic acid esters obtained by standard addition are between 90.3 and 107.4%, and the relative standard deviations obtained in repeated measurements are less than 9%.

  9. Lipids and Fatty Acids in Algae: Extraction, Fractionation into Lipid Classes, and Analysis by Gas Chromatography Coupled with Flame Ionization Detector (GC-FID).

    Science.gov (United States)

    Guihéneuf, Freddy; Schmid, Matthias; Stengel, Dagmar B

    2015-01-01

    Despite the number of biochemical studies exploring algal lipids and fatty acid biosynthesis pathways and profiles, analytical methods used by phycologists for this purpose are often diverse and incompletely described. Potential confusion and potential variability of the results between studies can therefore occur due to change of protocols for lipid extraction and fractionation, as well as fatty acid methyl esters (FAME) preparation before gas chromatography (GC) analyses. Here, we describe a step-by-step procedure for the profiling of neutral and polar lipids using techniques such as solid-liquid extraction (SLE), thin-layer chromatography (TLC), and gas chromatography coupled with flame ionization detector (GC-FID). As an example, in this protocol chapter, analyses of neutral and polar lipids from the marine microalga Pavlova lutheri (an EPA/DHA-rich haptophyte) will be outlined to describe the distribution of fatty acid residues within its major lipid classes. This method has been proven to be a reliable technique to assess changes in lipid and fatty acid profiles in several other microalgal species and seaweeds.

  10. Software safety hazard analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, J.D. [Lawrence Livermore National Lab., CA (United States)

    1996-02-01

    Techniques for analyzing the safety and reliability of analog-based electronic protection systems that serve to mitigate hazards in process control systems have been developed over many years, and are reasonably well understood. An example is the protection system in a nuclear power plant. The extension of these techniques to systems which include digital computers is not well developed, and there is little consensus among software engineering experts and safety experts on how to analyze such systems. One possible technique is to extend hazard analysis to include digital computer-based systems. Software is frequently overlooked during system hazard analyses, but this is unacceptable when the software is in control of a potentially hazardous operation. In such cases, hazard analysis should be extended to fully cover the software. A method for performing software hazard analysis is proposed in this paper.

  11. Gas chromatography/mass spectrometric analysis of methyl esters of N,N-dialkylaminoethane-2-sulfonic acids for verification of the Chemical Weapons Convention.

    Science.gov (United States)

    Pardasani, Deepak; Gupta, Arvinda K; Palit, Meehir; Shakya, Purushottam; Kanaujia, Pankaj K; Sekhar, K; Dubey, Devendra K

    2005-01-01

    This paper describes the synthesis and gas chromatography/electron ionization mass spectrometric (GC/EI-MS) analysis of methyl esters of N,N-dialkylaminoethane-2-sulfonic acids (DAESAs). These sulfonic acids are important environmental signatures of nerve agent VX and its toxic analogues, hence GC/EI-MS analysis of their methyl esters is of paramount importance for verification of the Chemical Weapons Convention. DAESAs were prepared by condensation of 2-bromoethane sulfonic acid with dialkylamines, and by condensation of dialkylaminoethyl chloride with sodium bisulfite. GC/EI-MS analysis of methyl esters of DAESAs yielded mass spectra; based on these spectra, generalized fragmentation routes are proposed that rationalize most of the characteristic ions.

  12. "Sour gas" hydrothermal jarosite: Ancient to modern acid-sulfate mineralization in the southern Rio Grande Rift

    Science.gov (United States)

    Lueth, V.W.; Rye, R.O.; Peters, L.

    2005-01-01

    deeply circulating meteoric water. Jarosite ??34S values range from -24??? to 5???, overlapping the values for barite and gypsum at the high end of the range and for sulfides at the low end. Most ??34S values for barite are 10.6??? to 13.1???, and many ??34S values for gypsum range from 13.1??? to 13.9??? indicating that a component of aqueous sulfate was derived from Permian evaporites (??34 S=12??2???). The requisite H2SO4 for jarosite formation was derived from oxidation of H2S which was likely largely sour gas derived from the thermochemical reduction of Permian sulfate. The low ??34S values for the precursor H2S probably resulted from exchange deeper in the basin with the more abundant Permian SO42- at ???150 to 200 ??C. Jarosite formed at shallow levels after the pH buffering capacity of the host rock (typically limestone) was neutralized by precipitation of earlier minerals. Some limestone-hosted deposits contain caves that may have been caused by the low pH of the deep basin fluids due to the addition of deep-seated HF and other magmatic gases during periods of renewed rifting. Caves in other deposits may be due to sulfuric acid speleogenesis as a result of H2S incursion into oxygenated groundwaters. The isotopic data in these "sour gas" jarosite occurrences encode a record of episodic tectonic or hydrologic processes that have operated in the rift over the last 10 my. ?? 2004 Elsevier B.V. All rights reserved.

  13. Numerical Simulation of Hazardous Gas Dispersion Around Buildings in Urban Environment%城市建筑群环境有毒有害气体扩散数值模拟

    Institute of Scientific and Technical Information of China (English)

    郑茂辉; 金敏; 许建明

    2013-01-01

    应用计算流体力学(CFD)原理和方法建立街区尺度点源泄漏扩散的数值模型,并经风洞试验结果验证其正确性.对街区建筑物扰动和两种来流风速(1.5 m·s-1,3.0 m·s-1)下近地面气云扩散过程及特性进行模拟与分析.结果表明:给定合适的计算参数,基于RNG k-ε模型和SIMPLE算法能够有效模拟复杂障碍物条件下有毒有害气体的扩散过程;近地面气云扩散受道路、建筑物布局和来流风速的影响明显,建筑物周围测点浓度同该处源距、方位、高度以及风向偏离程度存在密切联系;较大的来流风速加快气云水平输送,同时有利于浓度的稀释;泄漏停止后建筑物密集区间浓度稀释相对滞缓,可能对人群健康构成威胁.%A street-level computational fluid dynamics (CFD) model was established to simulate the movement characteristics of the released gas and the concentration distribution around the complex arrangement of buildings. A wind tunnel experiment about release and dispersion in building array was used to validate the model. Then numerical simulations were carried out with two different reference wind speeds, 1. 5 m·s-1 and 3.0 m·s-1, in a genuine urban area. The results show that, given appropriate parameters, the RNG κ—ε closure and SIMPLE algorithm can be employed to predict the dispersion process accurately in obstacle terrain. The time-varying concentration distributions near the ground highlight the influences of wind speed, road and building arrangement, on the dispersion. The sampling concentration around buildings is strongly affected by the positions of sampling points relative to source, including height, distance from the source, angle from wind direction, and so on. The higher wind velocity speeds up plume propagation, as well as concentration dilution process. The results also confirm that, among dense buildings the hazardous gas may stay much longer, which constitutes a threat to public

  14. Gas-Phase Partial Oxidation of Lignin to Carboxylic Acids over Vanadium Pyrophosphate and Aluminum-Vanadium-Molybdenum.

    Science.gov (United States)

    Lotfi, Samira; Boffito, Daria C; Patience, Gregory S

    2015-10-26

    Lignin is a complex polymer that is a potential feedstock for aromatic compounds and carboxylic acids by cleaving the β-O-4 and 5-5' linkages. In this work, a syringe pump atomizes an alkaline solution of lignin into a catalytic fluidized bed operating above 600 K. The vanadium heterogeneous catalysts convert all the lignin into carboxylic acids (up to 25 % selectivity), coke, carbon oxides, and hydrogen. Aluminum-vanadium-molybdenum mostly produced lactic acid (together with formic acid, acrylic acid, and maleic anhydride), whereas the vanadium pyrophosphate catalyst produced more maleic anhydride.

  15. Optimal control system design of an acid gas removal unit for an IGCC power plants with CO2 capture

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D.; Bhattacharyya, D.; Turton, R.; Zitney, S.

    2012-01-01

    Future IGCC plants with CO{sub 2} capture should be operated optimally in the face of disturbances without violating operational and environmental constraints. To achieve this goal, a systematic approach is taken in this work to design the control system of a selective, dual-stage Selexol-based acid gas removal (AGR) unit for a commercial-scale integrated gasification combined cycle (IGCC) power plant with pre-combustion CO{sub 2} capture. The control system design is performed in two stages with the objective of minimizing the auxiliary power while satisfying operational and environmental constraints in the presence of measured and unmeasured disturbances. In the first stage of the control system design, a top-down analysis is used to analyze degrees of freedom, define an operational objective, identify important disturbances and operational/environmental constraints, and select the control variables. With the degrees of freedom, the process is optimized with relation to the operational objective at nominal operation as well as under the disturbances identified. Operational and environmental constraints active at all operations are chosen as control variables. From the results of the optimization studies, self-optimizing control variables are identified for further examination. Several methods are explored in this work for the selection of these self-optimizing control variables. Modifications made to the existing methods will be discussed in this presentation. Due to the very large number of candidate sets available for control variables and due to the complexity of the underlying optimization problem, solution of this problem is computationally expensive. For reducing the computation time, parallel computing is performed using the Distributed Computing Server (DCS®) and the Parallel Computing® toolbox from Mathworks®. The second stage is a bottom-up design of the control layers used for the operation of the process. First, the regulatory control layer is

  16. Metabolomics study with gas chromatography-mass spectrometry for predicting valproic acid-induced hepatotoxicity and discovery of novel biomarkers in rat urine.

    Science.gov (United States)

    Lee, Min Sun; Jung, Byung Hwa; Chung, Bong Chul; Cho, Sung Hee; Kim, Ki Young; Kwon, Oh Seoung; Nugraha, Boya; Lee, Young-Joo

    2009-01-01

    Three different doses of valproic acid (20, 100, and 500 mg/kg/d) are administered orally to Sprague-Dawley rats for 5 days, and the feasibility of metabolomics with gas chromatography-mass spectrometry as a predictor of the hepatotoxicity of valproic acid is evaluated. Body weight is found to decrease with the 100-mg/kg/d dose and significantly decrease with the 500-mg/kg/d dose. Mean excreted urine volume is lowest in the 500-mg/kg/d group among all groups. The plasma level of alpha-glutathione-S-transferase, a sensitive and earlier biomarker for hepatotoxicity, increases significantly with administration of 100 and 500 mg/kg/d; however, there is not a significant difference in alpha-glutathione-S-transferase plasma levels between the control and 20-mg/kg/d groups. Clusters in partial least squares discriminant analysis score plots show similar patterns, with changes in physiological conditions and plasma levels of alpha-glutathione-S-transferase; the cluster for the control and 20-mg/kg/d groups does not clearly separate, but the clusters are separate for 100- and 500-mg/kg/d groups. A biomarker of hepatotoxicity, 8-hydroxy-2'-deoxyguanosine and octanoylcarnitine, is identified from nontargeted and targeted metabolic profiling. These results validate that metabolic profiling using gas chromatography-mass spectrometry could be a useful tool for finding novel biomarkers. Thus, a nontargeted metabolic profiling method is established to evaluate the hepatotoxicity of valproic acid and demonstrates proof-of-concept that metabolomic approach with gas chromatography-mass spectrometry has great potential for predicting valproic acid-induced hepatotoxicity and discovering novel biomarkers.

  17. Reclamation of acid, toxic coal spoils using wet flue gas desulfurization by-product, fly ash and sewage sludge. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kost, D.A.; Vimmerstedt, J.P.; Stehouwer, R.C.

    1997-03-01

    Establishment of vegetation on acid abandoned minelands requires modification of soil physical and chemical conditions. Covering the acid minesoil with topsoil or borrow soil is a common practice but this method may be restricted by availability of borrow soil and cause damage to the borrow site. An alternative approach is to use waste materials as soil amendments. There is a long history of using sewage sludge and fly ash as amendments for acid minesoils. Flue gas desulfurization (FGD) by-products are newer materials that are also promising amendments. Most flue gas sludges are mixtures of Calcium sulfate (CaSO{sub 4}), calcium sulfite (CaSO{sub 3}), calcium carbonate (CaCO{sub 3}), calcium hydroxide [Ca(OH){sub 2}], and fly ash. Some scrubbing processes produce almost pure gypsum (CaSO{sub 4}2H{sub 2}O). The primary purpose of the project is to evaluate two wet FGD by-products for effects on vegetation establishment and surface and ground water quality on an acid minesoil. One by-product from the Conesville, OH power plant (American Electric Power Service Corporation) contains primarily calcium sulfite and fly ash. The other by-product (Mg-gypsum FGD) from an experimental scrubber at the Zimmer power plant (Cincinnati Gas and Electric Company) is primarily gypsum with 4% magnesium hydroxide. These materials were compared with borrow soil and sewage sludge as minesoil amendments. Combinations of each FGD sludge with sewage sludge were also tested. This report summarizes two years of measurements of chemical composition of runoff water, ground water at two depths in the subsoil, soil chemical properties, elemental composition and yield of herbaceous ground cover, and elemental composition, survival and height of trees planted on plots treated with the various amendments. The borrow soil is the control for comparison with the other treatments.

  18. Determination of Aliphatic Acid and Ester in Ganoderma lucidum by Gas Chromatography-Time of Flight Mass Spectrometry%气相色谱-飞行时间质谱测定灵芝中脂肪酸(酯)

    Institute of Scientific and Technical Information of China (English)

    李前荣; 潘振; 尹浩

    2004-01-01

    The extracts of Ganoderma lucidum capsule powder (A) and natural ganoaerma lucidum (B) have been and analyzed by gas chromatography-time of flight mass spectrometry (GC-TOFMS). A great quantity of aliphatic acid (ester)Was observed at tR= 18min and tR = 20min, including the unsaturated aliphatic acid which is valuable. The relative content of aliphatic acid in sample A was 49.6%, of which 19.4% was linoleic acid, and those in sample B was 32.6%, of which 7.0% was linoleic acid. The relative content of aliphatic acids in sample A was higher than that in sample B.

  19. Sweet sour gas solution : a win-win Apache Canada plan sweeps an acid gas problem underground, reduces harmful emissions and boosts production

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.

    2004-08-01

    This article discusses the experiences of Apache Canada Ltd. in their efforts to cut costs and deal with environmental problems at their oil and gas field in northwest Alberta. Yields were low and the hydrocarbons sour, containing hydrogen sulphide and carbon dioxide. Some of the hydrogen sulphide is used to produce elemental sulphur (at the expense of releasing large amounts of greenhouse gas) and the rest has to be sequestered. Low sulphur prices have worsened the problem. The solution has been to inject both of the evolved gases into the ground where the hydrogen sulphide acts as a solvent forcing the oil downwards through the rock to a recovery well. The solvent acts to free the oil trapped in the rock. In this way Apache plans to produce more oil from its depleted deposits and sequester the hydrogen sulphide and carbon dioxide it produces anyway. It plans to stop the production of elemental sulphur since it is no longer economically viable. The end of sulphur production, and having gases sequestered in the oil extraction scheme mean that far fewer greenhouse gases are emitted to the atmosphere. 1 ref., 3 figs.

  20. Profiling of esterified fatty acids as biomarkers in the blood of dengue fever patients using a microliter-scale extraction followed by gas chromatography and mass spectrometry.

    Science.gov (United States)

    Khedr, Alaa; Hegazy, Maha; Kamal, Ahmed; Shehata, Mostafa A

    2015-01-01

    An improved gas chromatography with mass spectrometry procedure was developed to highlight the esterified fatty acids in 100 μL blood of dengue fever patients in the early febrile phase versus healthy volunteers. 24 adult patients and 24 healthy volunteers were included in this study. The recoveries of targeted esterified fatty acids content were in the range of 92.10-101.00% using methanol/dichloromethane (2:1, v/v) as the extraction solvent. An efficient chromatographic separation of targeted 17 esterified fatty acid methyl esters was obtained. The limits of detection and quantification were within the range of 16-131 and 53-430 ng/mL, respectively. The relative standard deviation of intraday and interday precision values ranged from 0.4 to 5.0%. The statistical data treatment showed a significant decrease of the content of four saturated fatty acids, C14:0, C15:0, C16:0, and C18:0 (P value dengue fever patients. Moreover, the amount of three omega-6 fatty acids including C18:3n6, C18:2n6, and C20:4n6 was dramatically decreased in the blood of dengue fever patients to a limit of 50 ± 10%.

  1. NGNP SITE 2 HAZARDS ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Wayne Moe

    2011-10-01

    The Next Generation Nuclear Plant (NGNP) Project initiated at Idaho National Laboratory (INL) by the U.S. Department of Energy pursuant to the 2005 Energy Policy Act, is based on research and development activities supported by the Generation IV Nuclear Energy Systems Initiative. The principal objective of the NGNP Project is to support commercialization of the high temperature gas-cooled reactor (HTGR) technology. The HTGR is a helium-cooled and graphite-moderated reactor that can operate at temperatures much higher than those of conventional light water reactor (LWR) technologies. Accordingly, it can be applied in many industrial applications as a substitute for burning fossil fuels, such as natural gas, to generate process heat in addition to producing electricity, which is the principal application of current LWRs. Nuclear energy in the form of LWRs has been used in the U.S. and internationally principally for the generation of electricity. However, because the HTGR operates at higher temperatures than LWRs, it can be used to displace the use of fossil fuels in many industrial applications. It also provides a carbon emission-free energy supply. For example, the energy needs for the recovery and refining of petroleum, for the petrochemical industry and for production of transportation fuels and feedstocks using coal conversion processes require process heat provided at temperatures approaching 800 C. This temperature range is readily achieved by the HTGR technology. This report summarizes a site assessment authorized by INL under the NGNP Project to determine hazards and potential challenges that site owners and HTGR designers need to be aware of when developing the HTGR design for co-location at industrial facilities, and to evaluate the site for suitability considering certain site characteristics. The objectives of the NGNP site hazard assessments are to do an initial screening of representative sites in order to identify potential challenges and restraints

  2. Gas chromatographic determination and mechanism of formation of D-amino acids occurring in fermented and roasted cocoa beans, cocoa powder, chocolate and cocoa shell.

    Science.gov (United States)

    Pätzold, R; Brückner, H

    2006-07-01

    Fermented cocoa beans of various countries of origin (Ivory Coast, Ghana, Sulawesi), cocoa beans roasted under defined conditions (100-150 degrees C; 30-120 min), low and high fat cocoa powder, various brands of chocolate, and cocoa shells were analyzed for their contents of free L-and D-amino acids. Amino acids were isolated from defatted products using a cation exchanger and converted into volatile N(O)-pentafluoropropionyl amino acid 2-propyl esters which were analyzed by enantioselective gas chromatography mass spectrometry on a Chirasil-L-Val capillary column. Besides common protein L-amino acids low amounts of D-amino acids were detected in fermented cocoa beans. Quantities of D-amino acids increased on heating. On roasting cocoa beans of the Forastero type from the Ivory Coast at 150 degrees C for 2 h, relative quantities of D-amino acids approached 17.0% D-Ala, 11.7% D-Ile, 11.1% D-Asx (Asp + Asn), 7.9% D-Tyr, 5.8% D-Ser, 4.8% D-Leu, 4.3% D-Phe, 37.0% D-Pro, and 1.2% D-Val. In cocoa powder and chocolate relative quantities amounted to 14.5% D-Ala, 10.6% D-Tyr, 9.8% D-Phe, 8.1% L-Asx, and 7.2% D-Ile. Lower quantities of other D-amino acids were also detected. In order to corroborate our hypothesis that D-amino acids are generated from Amadori compounds (fructose amino acids) formed in the course of the Maillard reaction, fructose-L-phenylalanine and fructose-D-phenylalanine were synthesized and heated at 200 degrees C for 5-60 min. Already after 5 min release of 11.7% D-Phe and 11.8% L-Phe in the free form could be analyzed. Based on the data a racemization mechanism is presented founded on the intermediate and reversible formation of an amino acid carbanion in the Amadori compounds.

  3. Identification of the botanical origin of pine nuts found in food products by gas-liquid chromatography analysis of fatty acid profile.

    Science.gov (United States)

    Destaillats, Frédéric; Cruz-Hernandez, Cristina; Giuffrida, Francesca; Dionisi, Fabiola

    2010-02-24

    Pine nuts are traditionally used in various part of the world for the preparation of desserts or sauces or in salads. Local production is not sufficient to cope with the high demand of pine nuts around the world, and countries such as China or Pakistan are exporting much of their production to Western countries. Almost all the nuts that are traditionally consumed belong to the Pinus genus, but over the past years, the number of consumer complaints following consumption of commercial pine nuts increased. Some consumers experienced taste disturbance lasting for up to two weeks after consumption. Food safety agencies raised some concerns regarding pine nuts imported from Asia and their association with taste disturbance. However, even though a formal association has not been found to date, the Pinus genus comprises species that are not classified as edible and could be eventually used to adulterate edible species. Pinus spp. seed lipids are known to contain very specific polyunsaturated fatty acids know as Delta5-olefinic acids. Seed fatty acid profile of conifers had been used in the past as a taxonomic marker, and in the present study to identify the botanical origin of pine nut in nine commercial products. Fast gas-liquid chromatography (GLC) was used to resolve the complete fatty acid profile of Pinus spp. samples in less than 5 min. A diagnostic index based on the relative levels of the main fatty acids including distinctive Delta5-olefinic acids was used to identify botanical origins. Results revealed the occurrence of the following Pinus spp. in commercial products: P. pinea, P. koraiensis, P. gerardiana, P. armandii and P. massoniana. The later two species, known as Chinese white pine and Chinese red pine, are only cultivated in China and are not listed as common source of edible pine nuts by the Food and Agriculture Organization (FAO). The present study shows that the botanical origin of pine nuts can be identified in products based on the fatty acid profile.

  4. Determination of Organic Acids in Forest Litters by a Capillary Gas Chromatography%毛细管气相色谱法测定森林凋落物中的有机酸

    Institute of Scientific and Technical Information of China (English)

    宋金凤; 刘永; 崔晓阳

    2004-01-01

    Organic acids in forest litters play important role in forests and forest soils. Based on the fresh litter materials of Fraxinus mandshurica and Larix olgensis forest in northeast China, a capillary gas chromatography procedure was established to determine organic acids in forest litters. Organic acids in forest litter were lixiviated and derived into corresponding esters with 7:100 (v:v) H2SO4:CH3OH at 60℃, extracted in CHCl3 and analyzed by capillary gas chromatography (GC) system. It resulted that, the method reported in this paper to separate, identify and determine organic acids in forest litter by GC was reliable and easy to operate. The disposal of sample was convenient, and the esterification with CH3 OH occurred while extracting organic acids with the same reagent, so volatilization loss of low-molecular-weight organic acids and oxidation of unsaturated fatty acids were avoided in course of condensation and esterification at high temperature when the conventional method to determine organic acids was used. Good selectivity was obtained, low-molecular-weight organic acids and high fatty acids could be determined simultaneously and accurately. Recovery of thirteen organic acids detected by adding standard samples ranged from 84.66% to 97.45% with relative standard deviation from 1.53% to 8.54%, and lowest detection limit of different organic acids was in range of 0.39 to 6.46 ng. The method could be used to determine organic acids in forest litters with satisfactory results.

  5. Natural hazards science strategy

    Science.gov (United States)

    Holmes, Jr., Robert R.; Jones, Lucile M.; Eidenshink, Jeffery C.; Godt, Jonathan W.; Kirby, Stephen H.; Love, Jeffrey J.; Neal, Christina A.; Plant, Nathaniel G.; Plunkett, Michael L.; Weaver, Craig S.; Wein, Anne; Perry, Suzanne C.

    2012-01-01

    The mission of the U.S. Geological Survey (USGS) in natural hazards is to develop and apply hazard science to help protect the safety, security, and economic well-being of the Nation. The costs and consequences of natural hazards can be enormous, and each year more people and infrastructure are at risk. USGS scientific research - founded on detailed observations and improved understanding of the responsible physical processes - can help to understand and reduce natural hazard risks and to make and effectively communicate reliable statements about hazard characteristics, such as frequency, magnitude, extent, onset, consequences, and where possible, the time of future events. To accomplish its broad hazard mission, the USGS maintains an expert workforce of scientists and technicians in the earth sciences, hydrology, biology, geography, social and behavioral sciences, and other fields, and engages cooperatively with numerous agencies, research institutions, and organizations in the public and private sectors, across the Nation and around the world. The scientific expertise required to accomplish the USGS mission in natural hazards includes a wide range of disciplines that this report refers to, in aggregate, as hazard science. In October 2010, the Natural Hazards Science Strategy Planning Team (H-SSPT) was charged with developing a long-term (10-year) Science Strategy for the USGS mission in natural hazards. This report fulfills that charge, with a document hereinafter referred to as the Strategy, to provide scientific observations, analyses, and research that are critical for the Nation to become more resilient to natural hazards. Science provides the information that decisionmakers need to determine whether risk management activities are worthwhile. Moreover, as the agency with the perspective of geologic time, the USGS is uniquely positioned to extend the collective experience of society to prepare for events outside current memory. The USGS has critical statutory

  6. Formation of gas-phase carbonyls from heterogeneous oxidation of polyunsaturated fatty acids at the air–water interface and of the sea surface microlayer

    Directory of Open Access Journals (Sweden)

    S. Zhou

    2013-07-01

    Full Text Available Motivated by the potential for reactive heterogeneous chemistry occurring at the ocean surface, gas-phase products were observed when a reactive sea surface microlayer (SML component, i.e. the polyunsaturated fatty acid (PUFA linoleic acid (LA, was exposed to gas-phase ozone at the air–seawater interface. Similar oxidation experiments were conducted with SML samples collected from two different oceanic locations, in the eastern equatorial Pacific Ocean and from the west coast of Canada. Online proton-transfer-reaction mass spectrometry (PTR-MS and light-emitting diode cavity enhanced differential optical absorption spectroscopy (LED-CE-DOAS were used to detect oxygenated gas-phase products from the ozonolysis reactions. The LA studies indicate that oxidation of a PUFA monolayer on seawater gives rise to prompt and efficient formation of gas phase aldehydes. The products are formed via the decomposition of primary ozonides which form upon the initial reaction of ozone with the carbon-carbon double bonds in the PUFA molecules. In addition, two highly reactive di-carbonyls, malondialdehyde (MDA and glyoxal, were also generated, likely as secondary products. Specific yields relative to reactant loss were 78%, 29%, 4% and <1% for n-hexanal, 3-nonenal, MDA and glyoxal, respectively, where the yields for MDA and glyoxal are likely lower limits. Heterogeneous oxidation of SML samples confirm for the first time that similar carbonyl products are formed via ozonolysis of environmental samples. The potential impact of such chemistry on the atmosphere of the marine boundary layer is discussed.

  7. Derivatisation/solid-phase microextraction followed by gas chromatography-mass spectrometry for the analysis of phenoxy acid herbicides in aqueous samples

    DEFF Research Database (Denmark)

    Nilsson, Torben; Baglio, Daniela; Galdo-Miguez, Isabel

    1998-01-01

    Different combinations of derivatisation and solid-phase microextraction followed by gas chromatography-mass spectrometry were optimised and evaluated for the analysis of phenoxy acid herbicides in water. The most successful derivatisation approach was aqueous-phase derivatisation with benzyl...... bromide. The benzyl esters were extracted most efficiently by the solid-phase microextraction fibre coated with polydimethylsiloxane-divinylbenzene. No carry-over problems were encountered with this fibre upon desorption at 250 degrees C. Detection limits in the ng/l range were obtained, while...

  8. The Effect of Temperature and Acid Gas Loading on Corrosion Behavior of API 5L X52 Carbon Steel in Amine Unit

    Science.gov (United States)

    Javidi, M.; Lalehparvar, M. M.; Ghassemi, A.

    2016-05-01

    The effect of temperature and H2S concentration on amine corrosion of API 5L X52 carbon steel in a CO2-saturated 25 wt.% diethanolamine solution was investigated via electrochemical techniques. It was found that increase in temperature from 25 to 80 °C resulted in severe increase in corrosion rate from 0.88 to 16.24 mpy due to increase in degradation rate of amine. Also, it was concluded that increase in H2S concentration led to increase in corrosion rate because of formation of more heat stable amine salts. The effect of temperature on corrosion rate was more significant than acid gas loading.

  9. Analysis of feed stream acid gas concentration effects on the transport properties and separation performance of polymeric membranes for natural gas sweetening: A comparison between a glassy and rubbery polymer

    KAUST Repository

    Vaughn, Justin T.

    2014-09-01

    A 6FDA based polyamide-imide, 6F-PAI-1, is compared to Pebax®, a commercially available rubbery polyether/polyamide block copolymer, for the simultaneous separation of CO2 and H2S from CH4. Feed streams of 20/20/60 and 5/45/50H2S/CO2/CH4 were used to compare the effect of acid gas concentration on the separation efficiency of 6F-PAI-1 and Pebax® under industrially relevant conditions. 6F-PAI-1 showed CO2/CH4 selectivities at 850psia total feed pressure of 30 and 40 for the 20/20/60 and 5/45/50 feed streams, respectively, while selectivity for H2S/CH4 was approximately 20 for both feeds. Pebax® showed selectivities of 40 and 10 for H2S/CH4 and CO2/CH4, respectively. Both selectivities were mostly independent of acid gas concentration in the feed, an unsurprising trend considering the non-glassy nature of this material. The selectivities in 6F-PAI-1 translated to less than 6% CH4 lost in the permeate stream for both feeds, while for the 5/45/50 feed, CH4 fraction in the permeate at 850psia was less than 4%. These promising results suggest that glassy polymers possessing favorable intrinsic plasticization resistance, such as 6F-PAI-1, may be appropriate for the typical case of natural gas sweetening where CO2 concentration in the feed is higher than it is for H2S. © 2014 Elsevier B.V.

  10. Compressed Gas Safety for Experimental Fusion Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Lee C. Cadwallader

    2004-09-01

    Experimental fusion facilities present a variety of hazards to the operators and staff. There are unique or specialized hazards, including magnetic fields, cryogens, radio frequency emissions, and vacuum reservoirs. There are also more general industrial hazards, such as a wide variety of electrical power, pressurized air, and cooling water systems in use, there are crane and hoist loads, working at height, and handling compressed gas cylinders. This paper outlines the projectile hazard assoicated with compressed gas cylinders and mthods of treatment to provide for compressed gas safety. This information should be of interest to personnel at both magnetic and inertial fusion experiments.

  11. Nanoassembled thin film gas sensors. III. Sensitive detection of amine odors using TiO2/poly(acrylic acid) ultrathin film quartz crystal microbalance sensors.

    Science.gov (United States)

    Lee, Seung-Woo; Takahara, Naoki; Korposh, Sergiy; Yang, Do-Hyeon; Toko, Kiyoshi; Kunitake, Toyoki

    2010-03-15

    Quartz crystal microbalance (QCM) gas sensors based on the alternate adsorption of TiO(2) and polyacrilic acid (PAA) were developed for the sensitive detection of amine odors. Individual TiO(2) gel layers could be regularly assembled with a thickness of approximately 0.3 nm by the gas-phase surface sol-gel process (GSSG). The thickness of the poly(acrylic acid) (PAA) layer is dependent on its molecular weight, showing different thicknesses of approximately 0.4 nm for PAA(25) (Mw 250,000) and 0.6-0.8 nm for PAA(400) (Mw 4,000,000). The QCM sensors showed a linear response to ammonia in the concentration range 0.3-15 ppm, depending on the deposition cycle of the alternate TiO(2)/PAA layer. The ammonia binding is based on the acid-base interaction to the free carboxylic acid groups of PAA and the limit of detection (LOD) of the 20-cycle TiO(2)/PAA(400) film was estimated to be 0.1 ppm when exposed to ammonia. The sensor response was very fast and stable in a wide relative humidity (rH) range of 30-70%, showing almost the same frequency changes at a given concentration of ammonia. Sensitivity to n-butylamine and ammonia was higher than to pyridine, which is owing to the difference of molecular weight and basicity of the amine analytes. The alternate TiO(2)/PAA(400) films have a highly effective ability to capture amine odors, and the ambient ammonia concentration of 15 ppm could be condensed up to approximately 20,000 ppm inside the films.

  12. Selection of Taste Markers Related to Lactic Acid Bacteria Microflora Metabolism for Chinese Traditional Paocai: A Gas Chromatography-Mass Spectrometry-Based Metabolomics Approach.

    Science.gov (United States)

    Zhao, Nan; Zhang, Chuchu; Yang, Qin; Guo, Zhuang; Yang, Bo; Lu, Wenwei; Li, Dongyao; Tian, Fengwei; Liu, Xiaoming; Zhang, Hao; Chen, Wei

    2016-03-23

    Traditional paocai brine (PB) is continuously propagated by back-slopping and contains numerous lactic acid bacteria (LAB) strains. Although PB is important for the quality of paocai (Chinese sauerkraut), the taste features, taste-related compounds of PB-paocai and the effects of LAB communities from PB on the taste compounds remain unclear. An electronic tongue was used to evaluate the taste features of 13 PB-paocai samples. Umami, saltiness, bitterness, sweetness, and aftertaste astringency were the main taste features of PB-paocai. A total of 14 compounds were identified as discriminant taste markers for PB-paocai via gas chromatography-mass spectrometry (GC-MS)-based multimarker profiling. A LAB co-culture (Lactobacillus plantarum, Lactobacillus buchneri, and Pediococcus ethanoliduran) from PB could significantly increase glutamic acid (umami), sucrose (sweetness), glycine (sweetness), lactic acid (sourness), and γ-aminobutyric acid in PB-paocai, which would endow it with important flavor features. Such features could then facilitate starter screening and fermentation optimization to produce paocai-related foods with better nutritional and sensory qualities.

  13. Quantification of trace fatty acid methyl esters in diesel fuel by using multidimensional gas chromatography with electron and chemical ionization mass spectrometry.

    Science.gov (United States)

    Webster, R L; Rawson, P M; Evans, D J; Marriott, P J

    2016-07-01

    Measurement of contamination of marine and naval diesel fuels (arising from product mixing or adulteration) with biodiesel or fatty acid methyl esters can be problematic, especially at very low levels. A suitable solution for this task for trace amounts of individual fatty acid methyl esters with resolution and quantification can be achieved by using a multidimensional gas chromatographic approach with electron and chemical ionization mass spectrometric detection. A unique column set comprising a 100 m methyl-siloxane nonpolar first dimension column and high-temperature ionic liquid column in the second dimension enabled identification of individual fatty acid methyl esters at below the lowest concentrations required to be reported in a diesel fuel matrix. Detection limits for individual fatty acid methyl esters compounds ranged from 0.5 to 5.0 mg/L, with excellent linearity up to 5000 mg/L and repeatability of the method from 1.3 to 3.2%. The method was applied to the analysis of diesel fuel samples with suspected biodiesel contamination. Contamination at 568 mg/L was calculated for an unknown sample and interpretation of the results permitted the determination of a likely source of the contamination.

  14. 76 FR 28326 - Pipeline Safety: National Pipeline Mapping System Data Submissions and Submission Dates for Gas...

    Science.gov (United States)

    2011-05-17

    ... Systems and Liquefied Natural Gas Annual Reports AGENCY: Pipeline and Hazardous Materials Safety... operators of gas transmission and gathering systems and Liquefied Natural Gas (LNG) facilities that they... to Pipeline and Liquefied Natural Gas Reporting Requirements'' (One Rule). This rulemaking...

  15. Quantitative analysis of aberrant fatty acid composition of zebrafish hepatic lipids induced by organochlorine pesticide using stable isotope-coded transmethylation and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Zhong, Hongying; Dong, Linjie; Dong, Qingjian; Ke, Changshu; Fu, Jieying; Wang, Xiaoli; Liu, Cong; Dai, Ling

    2012-07-01

    Organochlorine pesticides have been extensively used worldwide for agricultural purposes. Due to their resistance to metabolism, a major public health concern has been raised. Aberrant hepatic lipid composition has been a hallmark of many liver diseases associated with exposure to various toxins and chemicals. And thus lots of efforts have been focused on the development of analytical techniques that can rapidly and quantitatively determine the changes in fatty acid composition of hepatic lipids. In this work, changes in fatty acid composition of hepatic lipids in response to DDT (dichlorodiphenyltrichloroethane) exposure were quantitatively analyzed by a gas chromatography-mass spectrometric approach based on stable isotope-coded transmethylation. It has been quantitatively demonstrated that polyunsaturated fatty acids including C20:3n3, C20:4n6, and C22:6n3 decrease in response to DDT exposure. However, saturated long chain fatty acids including C16:0, C18:0, as well as monounsaturated long chain fatty acid C18:1n9 consistently increase in a DDT-concentration-dependent manner. In particular, much higher changes in the level of hepatic C16:0 and C18:0 for male fish were observed than that for female fish. These experimental results are in accordance with qualitative histopathological analysis that revealed liver morphological alterations. The stable isotope-coded mass spectrometric approach provides a reliable means for investigating hepatotoxicity associated with fatty acid synthesis, desaturation, mitochondrial beta-oxidation, and lipid mobilization. It should be useful in elucidation of hepatotoxic mechanisms and safety assessment of environmental toxins.

  16. Developing hazardous waste programs

    Science.gov (United States)

    Showstack, Randy

    Developing a fully operational hazardous waste regulatory system requires at least 10 to 15 years—even in countries with strong legal and bureaucratic institutions, according to a report on "The Evolution of Hazardous Waste Programs," which was funded by Resources for the Future (RFF) and the World Bank's South Asia Environment Group, and issued on June 4.The report, which compares the experiences of how four developed and four developing countries have created hazardous waste programs, indicates that hazardous waste issues usually do not become a pressing environmental issue until after countries have dealt with more direct threats to public health, such as contaminated drinking water and air pollution. The countries examined include Indonesia, Thailand, Germany, and the United States.

  17. Automated Standard Hazard Tool

    Science.gov (United States)

    Stebler, Shane

    2014-01-01

    The current system used to generate standard hazard reports is considered cumbersome and iterative. This study defines a structure for this system's process in a clear, algorithmic way so that standard hazard reports and basic hazard analysis may be completed using a centralized, web-based computer application. To accomplish this task, a test server is used to host a prototype of the tool during development. The prototype is configured to easily integrate into NASA's current server systems with minimal alteration. Additionally, the tool is easily updated and provides NASA with a system that may grow to accommodate future requirements and possibly, different applications. Results of this project's success are outlined in positive, subjective reviews complete by payload providers and NASA Safety and Mission Assurance personnel. Ideally, this prototype will increase interest in the concept of standard hazard automation and lead to the full-scale production of a user-ready application.

  18. Natural Hazards Image Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Photographs and other visual media provide valuable pre- and post-event data for natural hazards. Research, mitigation, and forecasting rely on visual data for...

  19. Flood Hazard Area

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The National Flood Hazard Layer (NFHL) data incorporates all Digital Flood Insurance Rate Map(DFIRM) databases published by FEMA, and any Letters Of Map Revision...

  20. Hazardous Waste Research Center

    Data.gov (United States)

    Federal Laboratory Consortium — The U.S. Army Engineer Waterways Experiment Station (WES) is playing a major role in development of technologies for cleanup of toxic and hazardous waste in military...

  1. Flood Hazard Boundaries

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The National Flood Hazard Layer (NFHL) data incorporates all Digital Flood Insurance Rate Map(DFIRM) databases published by FEMA, and any Letters Of Map Revision...

  2. What Are Volcano Hazards?

    Science.gov (United States)

    ... Sheet 002-97 Revised March 2008 What Are Volcano Hazards? Volcanoes give rise to numerous geologic and ... as far as 15 miles from the volcano. Volcano Landslides A landslide or debris avalanche is a ...

  3. Probabilistic Tsunami Hazard Analysis

    Science.gov (United States)

    Thio, H. K.; Ichinose, G. A.; Somerville, P. G.; Polet, J.

    2006-12-01

    The recent tsunami disaster caused by the 2004 Sumatra-Andaman earthquake has focused our attention to the hazard posed by large earthquakes that occur under water, in particular subduction zone earthquakes, and the tsunamis that they generate. Even though these kinds of events are rare, the very large loss of life and material destruction caused by this earthquake warrant a significant effort towards the mitigation of the tsunami hazard. For ground motion hazard, Probabilistic Seismic Hazard Analysis (PSHA) has become a standard practice in the evaluation and mitigation of seismic hazard to populations in particular with respect to structures, infrastructure and lifelines. Its ability to condense the complexities and variability of seismic activity into a manageable set of parameters greatly facilitates the design of effective seismic resistant buildings but also the planning of infrastructure projects. Probabilistic Tsunami Hazard Analysis (PTHA) achieves the same goal for hazards posed by tsunami. There are great advantages of implementing such a method to evaluate the total risk (seismic and tsunami) to coastal communities. The method that we have developed is based on the traditional PSHA and therefore completely consistent with standard seismic practice. Because of the strong dependence of tsunami wave heights on bathymetry, we use a full waveform tsunami waveform computation in lieu of attenuation relations that are common in PSHA. By pre-computing and storing the tsunami waveforms at points along the coast generated for sets of subfaults that comprise larger earthquake faults, we can efficiently synthesize tsunami waveforms for any slip distribution on those faults by summing the individual subfault tsunami waveforms (weighted by their slip). This efficiency make it feasible to use Green's function summation in lieu of attenuation relations to provide very accurate estimates of tsunami height for probabilistic calculations, where one typically computes

  4. Modeling Phase Equilibria for Acid Gas Mixtures Using the CPA Equation of State. I. Mixtures with H2S

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht;

    2010-01-01

    The Cubic-Plus-Association (CPA) equation of state is applied to a large variety of mixtures containing H2S, which are of interest in the oil and gas industry. Binary H2S mixtures with alkanes, CO2, water, methanol, and glycols are first considered. The interactions of H2S with polar compounds...

  5. K Basin Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    PECH, S.H.

    2000-08-23

    This report describes the methodology used in conducting the K Basins Hazard Analysis, which provides the foundation for the K Basins Final Safety Analysis Report. This hazard analysis was performed in accordance with guidance provided by DOE-STD-3009-94, Preparation Guide for U. S. Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports and implements the requirements of DOE Order 5480.23, Nuclear Safety Analysis Report.

  6. K Basins Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    WEBB, R.H.

    1999-12-29

    This report describes the methodology used in conducting the K Basins Hazard Analysis, which provides the foundation for the K Basins Safety Analysis Report (HNF-SD-WM-SAR-062, Rev.4). This hazard analysis was performed in accordance with guidance provided by DOE-STD-3009-94, Preparation Guide for U. S. Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports and implements the requirements of DOE Order 5480.23, Nuclear Safety Analysis Report.

  7. Phytoremediation of Hazardous Wastes

    Science.gov (United States)

    2007-11-02

    TITLE AND SUBTITLE Phytoremediation of Hazardous Wastes 6. AUTHOR(S) Steven C. McCutcheon, N. Lee Wolfe, Laura H. Carreria and Tse-Yuan Ou 5... phytoremediation (the use of plants to degrade hazardous contaminants) was developed. The new approach to phytoremediation involves rigorous pathway analyses...SUBJECT TERMS phytoremediation , nitroreductase, laccase enzymes, SERDP 15. NUMBER OF PAGES 8 16. PRICE CODE N/A 17. SECURITY CLASSIFICATION OF

  8. Efficiency of Gas-Phase Ion Formation in Matrix-Assisted Laser Desorption Ionization with 2,5-Dihydroxybenzoic Acid as Matrix

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyung Man; Ahn, Sung Hee; Bae, Yong Jin; Kim, Myung Soo [Seoul National Univ., Seoul (Korea, Republic of)

    2013-03-15

    Numbers of matrix- and analyte-derived ions and their sum in matrix-assisted laser desorption ionization (MALDI) of a peptide were measured using 2,5-dihydroxybenzoic acid (DHB) as matrix. As for MALDI with α-cyano-4-hydroxy cinnamic acid as matrix, the sum was independent of the peptide concentration in the solid sample, or was the same as that of pure DHB. This suggested that the matrix ion was the primary ion and that the peptide ion was generated by matrix-to-peptide proton transfer. Experimental ionization efficiencies of 10{sup -5}-10{sup -4} for peptides and 10{sup -8}-10{sup -7} for matrices are far smaller than 10.3-10.1 for peptides and 10{sup -5}-10{sup -3} for matrices speculated by Hillenkamp and Karas. Number of gas-phase ions generated by MALDI was unaffected by laser wavelength or pulse energy. This suggests that the main role of photo-absorption in MALDI is not in generating ions via a multi-photon process but in ablating materials in a solid sample to the gas phase.

  9. Importance of blood gas measurements in perinatal asphyxia and alternatives to restore the acid base balance status to improve the newborn performance

    Directory of Open Access Journals (Sweden)

    H. Orozco-Gregorio

    2007-01-01

    Full Text Available Prolonged or intermittent asphyxia in utero and during farrowing weakens piglets and renders them less capable of adaptation to extrauterine life. Piglets with lesser viability at birth have increased blood pCO2 and blood lactic acid concentrations and decreased blood pH. Moreover, the ability to thermoregulate during an acute cold stress is inversely related to umbilical blood lactate concentrations. Blood gas measurements and noninvasive estimations provide important information about oxygenation. The general goals of oxygen therapy in the neonate are to maintain adequate arterial PaO2 and SaO2, and to minimize cardiac work and the work of breathing. Arterial blood gas determinations of pCO2 provide the most accurate determinations of the adequacy of alveolar ventilation. Blood gases obtained in the immediate perinatal period can help assess perinatal asphyxia, but particular attention must be paid to the sampling site, the time of life, and the possible and proven diagnoses. The decision to obtain blood gases must be weighed by the individual clinician against the potential benefits. Current measures for restoring the acid base balance status in the newborn with perinatal asphyxia are discussed.

  10. Training hazard perception skills. [previously known as: Training hazard perception.

    NARCIS (Netherlands)

    2010-01-01

    Hazard perception is an essential skill in the driving task, but it is still badly developed among novice drivers. Hazard perception consists of more than perceiving hazards. It also concerns appraising the seriousness of the hazards, and knowing how to act to avert them. There are indications that

  11. Transportation of Hazardous Materials Emergency Preparedness Hazards Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Blanchard, A.

    2000-02-28

    This report documents the Emergency Preparedness Hazards Assessment (EPHA) for the Transportation of Hazardous Materials (THM) at the Department of Energy (DOE) Savannah River Site (SRS). This hazards assessment is intended to identify and analyze those transportation hazards significant enough to warrant consideration in the SRS Emergency Management Program.

  12. Quantification of fatty acids in the muscle of Antarctic fish Trematomus bernacchii by gas chromatography-mass spectrometry: Optimization of the analytical methodology.

    Science.gov (United States)

    Truzzi, C; Illuminati, S; Annibaldi, A; Antonucci, M; Scarponi, G

    2017-04-01

    This work presents data on the quantification of fatty acids (FAs, in terms of mass unit per tissue weight) in the muscle of Trematomus bernacchii, a key species in Antarctica, often used as bioindicator for contamination studies. Modifications in fatty acids content should be considered a useful biomarker to study how contaminants affect Antarctic biota. Until now, very few studies quantified fatty acids of muscle of T. bernacchii, and only as percentage of a single fatty acid on total lipids. To perform the quantification of fatty acids, we used an analytical method based on a fast microwave-assisted extraction of lipids from a lyophilized sample, a base-catalyzed trans-esterification of lipid extract to obtain Fatty Acids Methyl Esters (FAMEs), and a separation and identification of FAMEs by gas chromatography-mass spectrometry. With the optimized and validated method, a fast and accurate separation of Fatty Acids Methyl Esters was performed in 43 min. The linearity was checked up to about 320 μg mL(-1); limit of detection and limit of quantification are in the range 4-22 μg mL(-1) and 13-66 μg mL(-1), respectively. The optimized method showed a good accuracy and precision. Major fatty acids were 14:0, 16:0, 16:1n7, 18:1n9, 18:1n7, 20:1n9, 20:5n3 and 22:6n3. Quantified FAs compute for about 47 mg g(-1) tissue dry weight (dw), with 9.1 ± 0.1 mg g(-1) dw of saturated FAs, 25.5 ± 0.1 mg g(-1) dw of mono-unsaturated FAs, and 12.2 ± 0.1 mg g(-1) dw of poly-unsaturated FAs.

  13. Determination of Labeled Fatty Acids Content in Milk Products, Infant Formula, and Adult/Pediatric Nutritional Formula by Capillary Gas Chromatography: Collaborative Study, Final Action 2012.13.

    Science.gov (United States)

    Golay, Pierre-Alain; Moulin, Julie

    2016-01-01

    A collaborative study was conducted on AOAC First Action Method 2012.13 "Determination of Labeled Fatty Acids Content in Milk Products and Infant Formula by Capillary Gas Chromatography," which is based on an initial International Organization for Standardization (ISO)-International Dairy Federation (IDF) New Work Item that has been moved forward to ISO 16958:2015|IDF 231:2015 in November 2015. It was decided to merge the two activities after the agreement signed between ISO and AOAC in June 2012 to develop common standards and to avoid duplicate work. The collaborative study was performed after having provided highly satisfactory single-laboratory validation results [Golay, P.A., & Dong, Y. (2015) J. AOAC Int. 98, 1679-1696] that exceeded the performance criteria defined in AOAC Standard Method Performance Requirement (SMPR(®)) 2012.011 (September 29, 2012) on 12 products selected by the AOAC Stakeholder Panel on Infant Formula (SPIFAN). After a qualification period of 1 month, 18 laboratories participated in the fatty acids analysis of 12 different samples in duplicate. Six samples were selected to meet AOAC SPIFAN requirements (i.e., infant formula and adult nutritionals in powder and liquid formats), and the other Six samples were selected to meet ISO-IDF requirements (i.e., dairy products such as milk powder, liquid milk, cream, butter, infant formula with milk, and cheese). The fatty acids were analyzed directly in all samples without preliminary fat extraction, except in one sample (cheese). Powdered samples were analyzed after dissolution (i.e., reconstitution) in water, whereas liquid samples (or extracted fat) were analyzed directly. After addition of the internal standards solution [C11:0 fatty acid methyl ester (FAME) and C13:0 triacylglycerols (TAG)] to the samples, fatty acids attached to lipids were transformed into FAMEs by direct transesterification using methanolic sodium methoxide. FAMEs were separated using highly polar capillary GLC and were

  14. Comparison of four extraction/methylation analytical methods to measure fatty acid composition by gas chromatography in meat.

    Science.gov (United States)

    Juárez, M; Polvillo, O; Contò, M; Ficco, A; Ballico, S; Failla, S

    2008-05-01

    Four different extraction-derivatization methods commonly used for fatty acid analysis in meat (in situ or one-step method, saponification method, classic method and a combination of classic extraction and saponification derivatization) were tested. The in situ method had low recovery and variation. The saponification method showed the best balance between recovery, precision, repeatability and reproducibility. The classic method had high recovery and acceptable variation values, except for the polyunsaturated fatty acids, showing higher variation than the former methods. The combination of extraction and methylation steps had great recovery values, but the precision, repeatability and reproducibility were not acceptable. Therefore the saponification method would be more convenient for polyunsaturated fatty acid analysis, whereas the in situ method would be an alternative for fast analysis. However the classic method would be the method of choice for the determination of the different lipid classes.

  15. Structural analysis of lignin by pyrolysis-gas chromatography. 7. Conditions for acid hydrolysis of wood pulp and characteristics of acid-insoluble residues; Netsubunkai gas chromatography ni yoru lignin no kozo kaiseki. 7. Mokuzai pulp no sankasuibunkai joken to sanfuyosei zansa no seijo

    Energy Technology Data Exchange (ETDEWEB)

    Oi, H.; Ju, Y.; Kuroda, K. [The University of Tsukuba, Tsukuba (Japan)

    1997-10-01

    In order to simply analyze lignin present in wood/pulp and the carbohydrate composition, an attempt was made to improve hydrolysis conditions. The tests used pulp samples from degreased akamatsu (Pinus densiflora) meals, akamatsu holocellulose and akamatsu chips. Four methods were tested for acid hydrolysis; the Klason lignin, Yoshiwara, carbohydrate composition and modified carbohydrate composition methods. The acid-insoluble residues were analyzed by pyrolysis-gas chromatography, and the pyrograms prepared under different hydrolysis conditions were compared with each other. The test results indicate that the lignin and composition methods need 2.5h of the primary hydrolysis treatment with 72% sulfuric acid, time of this treatment should be increased to 2.5h for the carbohydrate composition method, and the modified carbohydrate method can quantitatively analyze lignin present in many wood and pulp samples. 7 refs., 6 figs., 3 tabs.

  16. Nitrous Oxide Explosive Hazards

    Science.gov (United States)

    2008-05-01

    be explained by formation of liquid blobs formed by gas expansion cooling and fast conversion of liquid blobs to gas when they entered warm zones...conditions of low pressure and lack of energetic stimulus needed to start a decomposing flame process. Warm zone volumes with turbulent gas flow have been...decomposition conditions. (13) - High pressure gas cools during venting. With flow restriction in vent blobs of liquid could intermittently impede

  17. Novel pre-fractionation method of trans fatty acids by gas chromatography with silver-ion cartridge column.

    Science.gov (United States)

    Goto, Hirofumi; Shionoya, Noriko; Sugie, Megumi; Tominaga, Makoto; Shimelis, Olga; Taniguchi, Makoto; Igarashi, Tomoji; Hirata, Yoshiaki

    2012-01-01

    We developed a novel pre-separation method of trans fatty acids (TFAs) using a silver-ion cartridge column and GC. As a preliminary study, a mixture of fatty acid methyl esters consisting of saturated, cis-unsaturated, and trans-unsaturated fatty acids was dissolved in dichloromethane and loaded onto a Bond Elut SCX ion-exchange cartridge column that was converted to the silver-ion form. The column was then eluted with dichloromethane to obtain the saturated fatty acids, dichloromethane/ethyl acetate (90/10) for the trans mono-ene, dichloromethane/ethyl acetate (65/35) for the cis mono-ene, dichloromethane/acetone (60/40) for the trans di-ene, and acetone/acetonitrile (80/20) for the others. Satisfactory separation of the cis/trans isomers was confirmed by GC analysis. To generalize this technique, the elution conditions of the ready-to-use Discovery Ag-ION SPE cartridge column were also optimized. Both cartridge columns had good separation, recovery, and repeatability. Peer laboratory verification was carried out between two laboratories using different production lots of the ready-to-use cartridge column, and the robustness of the product and reproducibility of the method were found to be satisfactory. This technique is therefore a powerful tool not only for routine analyses of TFAs in oils, fats, and foods but also for detailed analyses of TFAs in various research fields.

  18. Comparison of the Use of Gas Chromotography, Spectrophotometry, and Near Infrared Spectropscopy to Quantify Prussic Acid Potential in Forages

    Science.gov (United States)

    Sorghum [Sorghum bicolor (L.) Moench] has been shown to contain the cyanogenic glycoside dhurrin, which is responsible for the disorder known as prussic acid poisoning in livestock. The current standard method for estimating HCN uses spectrophotometery to measure the aglycone of the dhurrin, p-hydro...

  19. Optimization of acetic acid production from synthesis gas by chemolithotrophic bacterium--Clostridium aceticum using statistical approach.

    Science.gov (United States)

    Sim, Jia Huey; Kamaruddin, Azlina Harun

    2008-05-01

    Efforts in optimizing reducing agents, cysteine-HCl.H2O and sodium sulfide in order to attain satisfactory responses during acetic acid fermentation have been carried out in this study. Cysteine-HCl.H2O each with five concentrations (0.00-0.50 g/L) was optimized one at a time and followed by sodium sulfide component (0.00-0.50 g/L). Response surface methodology (RSM) was used to determine the optimum concentrations of cysteine-HCl.H2O and sodium sulfide. The statistical analysis showed that the amount of cells produced and efficiency in CO conversion were not affected by sodium sulfide concentration. However, sodium sulfide is required as it does influence the acetic acid production. The optimum reducing agents for acetic acid fermentation was at 0.30 g/L cysteine-HCl.H2O and sodium sulfide respectively and when operated for 60 h cultivation time resulted in 1.28 g/L acetic acid production and 100% CO conversion.

  20. Gas chromatographic determination of acid herbicides in surface water samples with electron-capture detection and mass spectrometric confirmation

    NARCIS (Netherlands)

    Vink, M.; Poll, J.M. van der

    1996-01-01

    The development of a multi-residue method for the determination of eight polar acidic herbicides (MCPA, MCPB, mecoprop, 2,4-D, dichlorprop, bentazone, dicamba and dikegulac) in surface water is described. The method involves an off-line solid-phase extraction (SPE) procedure prior to instrumental an

  1. Photocatalytic H2 Production Using Pt-TiO2 in the Presence of Oxalic Acid: Influence of the Noble Metal Size and the Carrier Gas Flow Rate

    Directory of Open Access Journals (Sweden)

    Ákos Kmetykó

    2014-10-01

    Full Text Available The primary objective of the experiments was to investigate the differences in the photocatalytic performance when commercially available Aeroxide P25 TiO2 photocatalyst was deposited with differently sized Pt nanoparticles with identical platinum content (1 wt%. The noble metal deposition onto the TiO2 surface was achieved by in situ chemical reduction (CRIS or by mixing chemically reduced Pt nanoparticle containing sols to the aqueous suspensions of the photocatalysts (sol-impregnated samples, CRSIM. Fine and low-scale control of the size of resulting Pt nanoparticles was obtained through variation of the trisodium citrate concentration during the syntheses. The reducing reagent was NaBH4. Photocatalytic activity of the samples and the reaction mechanism were examined during UV irradiation (λmax = 365 nm in the presence of oxalic acid (50 mM as a sacrificial hole scavenger component. The H2 evolution rates proved to be strongly dependent on the Pt particle size, as well as the irradiation time. A significant change of H2 formation rate during the oxalic acid transformation was observed which is unusual. It is probably regulated both by the decomposition rate of accumulated oxalic acid and the H+/H2 redox potential on the surface of the catalyst. The later potential is influenced by the concentration of the dissolved H2 gas in the reaction mixture.

  2. Identification of Aircraft Hazards

    Energy Technology Data Exchange (ETDEWEB)

    K. Ashley

    2006-12-08

    Aircraft hazards were determined to be potentially applicable to a repository at Yucca Mountain in ''Monitored Geological Repository External Events Hazards Screening Analysis'' (BSC 2005 [DIRS 174235], Section 6.4.1). That determination was conservatively based upon limited knowledge of flight data in the area of concern and upon crash data for aircraft of the type flying near Yucca Mountain. The purpose of this report is to identify specific aircraft hazards that may be applicable to a monitored geologic repository (MGR) at Yucca Mountain, using NUREG-0800, ''Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants'' (NRC 1987 [DIRS 103124], Section 3.5.1.6), as guidance for the inclusion or exclusion of identified aircraft hazards. The intended use of this report is to provide inputs for further screening and analysis of identified aircraft hazards based upon the criteria that apply to Category 1 and Category 2 event sequence analyses as defined in 10 CFR 63.2 [DIRS 176544] (Section 4). The scope of this report includes the evaluation of military, private, and commercial use of airspace in the 100-mile regional setting of the repository at Yucca Mountain with the potential for reducing the regional setting to a more manageable size after consideration of applicable screening criteria (Section 7).

  3. IDENTIFICATION OF AIRCRAFT HAZARDS

    Energy Technology Data Exchange (ETDEWEB)

    K.L. Ashley

    2005-03-23

    Aircraft hazards were determined to be potentially applicable to a repository at Yucca Mountain in the ''Monitored Geological Repository External Events Hazards Screening Analysis'' (BSC 2004, Section 6.4.1). That determination was conservatively based on limited knowledge of flight data in the area of concern and on crash data for aircraft of the type flying near Yucca Mountain. The purpose of this report is to identify specific aircraft hazards that may be applicable to a Monitored Geologic Repository (MGR) at Yucca Mountain using NUREG-0800, ''Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants'' (NRC 1987, Section 3.5.1.6), as guidance for the inclusion or exclusion of identified aircraft hazards. NUREG-0800 is being used here as a reference because some of the same considerations apply. The intended use of this report is to provide inputs for further screening and analysis of the identified aircraft hazards based on the criteria that apply to Category 1 and 2 event sequence analyses as defined in 10 CFR 63.2 (see Section 4). The scope of this technical report includes the evaluation of military, private, and commercial use of airspace in the 100-mile regional setting of the MGR at Yucca Mountain with the potential for reducing the regional setting to a more manageable size after consideration of applicable screening criteria (see Section 7).

  4. Apparatus for incinerating hazardous waste

    Science.gov (United States)

    Chang, R.C.W.

    1994-12-20

    An apparatus is described for incinerating wastes, including an incinerator having a combustion chamber, a fluid-tight shell enclosing the combustion chamber, an afterburner, an off-gas particulate removal system and an emergency off-gas cooling system. The region between the inner surface of the shell and the outer surface of the combustion chamber forms a cavity. Air is supplied to the cavity and heated as it passes over the outer surface of the combustion chamber. Heated air is drawn from the cavity and mixed with fuel for input into the combustion chamber. The pressure in the cavity is maintained at least approximately 2.5 cm WC higher than the pressure in the combustion chamber. Gases cannot leak from the combustion chamber since the pressure outside the chamber (inside the cavity) is higher than the pressure inside the chamber. The apparatus can be used to treat any combustible wastes, including biological wastes, toxic materials, low level radioactive wastes, and mixed hazardous and low level transuranic wastes. 1 figure.

  5. Household hazardous waste

    DEFF Research Database (Denmark)

    Fjelsted, Lotte; Christensen, Thomas Højlund

    2007-01-01

    incinerated. Allowing household paint waste to be collected with ordinary household waste is expected to reduce the cost of handling household hazardous waste, since paint waste in Denmark comprises the major fraction of household hazardous waste.......'Paint waste', a part of the 'household hazardous waste', amounting to approximately 5 tonnes was collected from recycling stations in two Danish cities. Sorting and analyses of the waste showed paint waste comprised approximately 65% of the mass, paint-like waste (cleaners, fillers, etc...... and the paint waste was less contaminated with heavy metals than was the ordinary household waste. This may suggest that households no longer need to source-segregate their paint if the household waste is incinerated, since the presence of a small quantity of solvent-based paint will not be harmful when...

  6. A novel system for continuous production of formic acid based on recycling of yellow phosphorous tail gas%连续化回收黄磷尾气副产甲酸的新系统

    Institute of Scientific and Technical Information of China (English)

    刘宝庆; 张义堃; 蒋家羚; 林兴华; 何锦林

    2012-01-01

    The recycling of yellow phosphorous tail gas rich in carbon monoxide is related to energy conservation and environment protection. Based on the analysis of existing technologies for the recycling of yellow phosphorous tail gas, a novel continuous process was developed by combining the resources recycling of yellow phosphorous tail gas with formic acid production, which made phosphoric acid acidification method as the core and could produce formic acid with high quality and low cost on the basis of considering the high and variable viscosity of system and the rationality of energy utilization. At the same time, a multilevel acidification reactor was also designed by integrating the reaction, heating and condensation reflux, which was divided into several reaction regions and equipped with different stirrers. The novel acidification reactor as the core equipment had the advantages of compact structure, energy conservation and wide adaptability.

  7. Dust Hazard Management in the Outer Solar System

    Science.gov (United States)

    Seal, David A.

    2012-01-01

    Most robotic missions to the outer solar system must grapple with the hazards posed by the dusty rings of the gas giants. Early assessments of these hazards led simply to ring avoidance due to insufficient data and high uncertainties on the dust population present in such rings. Recent approaches, principal among them the Cassini dust hazard management strategy, provide useful results from detailed modeling of spacecraft vulnerabilities and dust hazard regions, which along with the range of mission trajectories are used to to assess the risks posed by each passage through a zone of potential hazard. This paper shows the general approach used to implement the analysis for Cassini, with recommendations for future outer planet missions.

  8. Lightning hazards to aircraft

    Science.gov (United States)

    Corn, P. B.

    1978-01-01

    Lightning hazards and, more generally, aircraft static electricity are discussed by a representative for the Air Force Flight Dynamics Laboratory. An overview of these atmospheric electricity hazards to aircraft and their systems is presented with emphasis on electrical and electronic subsystems. The discussion includes reviewing some of the characteristics of lightning and static electrification, trends in weather and lightning-related mishaps, some specific threat mechanisms and susceptible aircraft subsystems and some of the present technology gaps. A roadmap (flow chart) is presented to show the direction needed to address these problems.

  9. Use of redox potential modification by gas improves microbial quality, color retention, and ascorbic acid stability of pasteurized orange juice.

    Science.gov (United States)

    Alwazeer, Duried; Delbeau, Carole; Divies, Charles; Cachon, Rémy

    2003-12-15

    The aim of this paper was to study the effect of both redox potential (Eh) and pasteurization of orange juice on stability of color and ascorbic acid, and growth recovery of microorganisms during storage at 15 degrees C for 7 weeks. Three conditions of Eh, +360 mV (ungassed), +240 mV (gassed with N2), and -180 mV (gassed with N2-H2) were applied to orange juice. Both thermal destruction and recovery of sublethally heat-injured cells of Lactobacillus plantarum and Saccharomyces cerevisiae were investigated. While oxidizing conditions were the most effective for thermal destruction of L. plantarum and S. cerevisiae, reducing conditions decreased recovery of heated cells of S. cerevisiae. In addition, gassing the juice with N2 or N2-H2 increased color retention and ascorbic acid stability. The present study demonstrated that juice must be reduced just after the heat treatment in order, firstly, to maximize microbial destruction during pasteurization, and secondly, to prevent the development of microorganisms and stabilize color and ascorbic acid during storage.

  10. Ethanol and Acetic Acid Production from Carbon Monoxide in a Clostridium Strain in Batch and Continuous Gas-Fed Bioreactors

    Science.gov (United States)

    Nalakath Abubackar, Haris; Veiga, María C.; Kennes, Christian

    2015-01-01

    The effect of different sources of nitrogen as well as their concentrations on the bioconversion of carbon monoxide to metabolic products such as acetic acid and ethanol by Clostridium autoethanogenum was studied. In a first set of assays, under batch conditions, either NH4Cl, trypticase soy broth or yeast extract (YE) were used as sources of nitrogen. The use of YE was found statistically significant (p supply, in order to estimate the effect of running conditions on products and biomass formation. The bioreactors were operated under different conditions, i.e., EXP1 (pH = 5.75, YE 1g/L), EXP2 (pH = 4.75, YE 1 g/L) and EXP3 (pH = 5.75, YE 0.2 g/L). When compared to EXP2 and EXP3, it was found that EXP1 yielded the maximum biomass accumulation (302.4 mg/L) and products concentrations, i.e., acetic acid (2147.1 mg/L) and ethanol (352.6 mg/L). This can be attributed to the fact that the higher pH and higher YE concentration used in EXP1 stimulated cell growth and did, consequently, also enhance metabolite production. However, when ethanol is the desired end-product, as a biofuel, the lower pH used in EXP2 was more favourable for solventogenesis and yielded the highest ethanol/acetic acid ratio, reaching a value of 0.54. PMID:25608591

  11. 77 FR 70543 - Pipeline Safety: Meeting of the Gas Pipeline Advisory Committee and the Liquid Pipeline Advisory...

    Science.gov (United States)

    2012-11-26

    ... for natural gas pipelines and for hazardous liquid pipelines. Both committees were established under... TRANSPORTATION Pipeline and Hazardous Materials Safety Administration Pipeline Safety: Meeting of the Gas Pipeline Advisory Committee and the Liquid Pipeline Advisory Committee AGENCY: Pipeline and...

  12. Improving the purity of GaN grown by the ammonothermal method with in-autoclave gas-phase acidic mineralizer synthesis

    Science.gov (United States)

    Tomida, D.; Chichibu, S. F.; Kagamitani, Y.; Bao, Q.; Hazu, K.; Simura, R.; Sugiyama, K.; Yokoyama, C.; Ishiguro, T.; Fukuda, T.

    2012-06-01

    In-autoclave synthesis of a gas-phase acidic mineralizer was investigated for high-purity GaN growth by the ammonothermal (AT) method. To reduce oxygen contamination of GaN from highly hygroscopic NH4Cl powder, purified NH3 and HCl gases were introduced sequentially fed into a Pt-lined autoclave to synthesize NH4Cl within the autoclave. The autoclave was pre-charged with GaN seed wafers and polycrystalline precursors, and carefully dehydrated under dynamic vacuum. Because of the decrease in oxygen concentration, the lattice parameter approached the intrinsic value. The Ga-polar layers exhibit a near-band-edge emission peak at room temperature.

  13. Prenatal diagnosis of methylmalonic aciduria by measuring methylmalonic acid in dried amniotic fluid on filter paper using gas chromatography-mass spectrometry.

    Science.gov (United States)

    Inoue, Yoshito; Ohse, Morimasa

    2011-06-01

    Methylmalonic aciduria is a common inherited metabolic disorder. Methylmalonic acid (MMA), a key indicator of methylmalonic aciduria, increases in the amniotic fluid of affected fetuses. For prenatal diagnosis, the MMA in amniotic fluid can be measured by stable-isotope dilution gas chromatography-mass spectrometry. Here, we quantified the MMA in cell-free amniotic fluid samples that had been dried on filter paper and transported at ambient temperatures, and compared the results with data obtained from the original amniotic fluid. Our results indicated that the filter paper method was reproducible and accurate enough to be applied to clinical analysis. We also used the filter paper method to screen at-risk fetuses and obtained a clear diagnosis in each case. We conclude that our method enables the prenatal diagnosis of methylmalonic aciduria using practical procedures and a simplified method for transporting the samples.

  14. Combined quantification of faecal sterols, stanols, stanones and bile acids in soils and terrestrial sediments by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Birk, Jago Jonathan; Dippold, Michaela; Wiesenberg, Guido L B; Glaser, Bruno

    2012-06-15

    Faeces incorporation can alter the concentration patterns of stanols, stanones, Δ(5)-sterols and bile acids in soils and terrestrial sediments. A joint quantification of these substances would give robust and specific information about the faecal input. Therefore, a method was developed for their purification and determination via gas chromatography-mass spectrometry (GC-MS) based on a total lipid extract (TLE) of soils and terrestrial sediments. Stanols, stanones, Δ(5)-steroles and bile acids were extracted by a single Soxhlet extraction yielding a TLE. The TLE was saponified with KOH in methanol. Sequential liquid-liquid extraction was applied to recover the biomarkers from the saponified extract and to separate the bile acids from the neutral stanoles, stanones and Δ(5)-steroles. The neutral fraction was directly purified using solid phase extraction (SPE) columns packed with 5% deactivated silica gel. The bile acids were methylated in dry HCl in methanol and purified on SPE columns packed with activated silica gel. A mixture of hexamethyldisilazane (HMDS), trimethylchlorosilane (TMCS) and pyridine was used to silylate the hydroxyl groups of the stanols and Δ(5)-sterols avoiding a silylation of the keto groups of the stanones in their enol-form. Silylation of the bile acids was carried out with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) containing N-trimethylsilylimidazole (TSIM). TLEs from a set of soils with different physico-chemical properties were used for method evaluation and for comparison of amounts of faecal biomarkers analysed with saponification and without saponification of the TLE. Therefore, a Regosol, a Podzol and a Ferralsol were sampled. To proof the applicability of the method for faecal biomarker analyses in archaeological soils and sediments, additional samples were taken from pre-Columbian Anthrosols in Amazonia and an Anthrosol from a site in central Europe settled since the Neolithic. The comparison of the amounts of steroids

  15. Effective methylation of phosphonic acids related to chemical warfare agents mediated by trimethyloxonium tetrafluoroborate for their qualitative detection and identification by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Valdez, Carlos A; Leif, Roald N; Alcaraz, Armando

    2016-08-24

    The effective methylation of phosphonic acids related to chemical warfare agents (CWAs) employing trimethyloxonium tetrafluoroborate (TMO·BF4) for their qualitative detection and identification by gas chromatography-mass spectrometry (GC-MS) is presented. The methylation occurs in rapid fashion (1 h) and can be conveniently carried out at ambient temperature, thus providing a safer alternative to the universally employed diazomethane-based methylation protocols. Optimization of the methylation parameters led us to conclude that methylene chloride was the ideal solvent to carry out the derivatization, and that even though methylated products can be observed surfacing after only 1 h, additional time was not found to be detrimental but beneficial to the process particularly when dealing with analytes at low concentrations (∼10 μg mL(-1)). Due to its insolubility in methylene chloride, TMO·BF4 conveniently settles to the bottom during the reaction and does not produce additional interfering by-products that may further complicate the GC-MS analysis. The method was demonstrated to successfully methylate a variety of Schedule 2 phosphonic acids, including their half esters, resulting in derivatives that were readily detected and identified using the instrument's spectral library. Most importantly, the method was shown to simultaneously methylate a mixture of the organophosphorus-based nerve agent hydrolysis products: pinacolyl methylphosphonate (PMPA), cyclohexyl methylphosphonate (CyMPA) and ethyl methylphosphonate (EMPA) (at a 10 μg mL(-1) concentration each) in a fatty acid ester-rich organic matrix (OPCW-PT-O3) featured in the 38th Organisation for the Prohibition of Chemical Weapons (OPCW) Proficiency Test. In addition, the protocol was found to effectively methylate N,N-diethylamino ethanesulfonic acid and N,N-diisopropylamino ethanesulfonic acid that are products arising from the oxidative degradation of the V-series agents VR and VX respectively. The

  16. A field-deployable, chemical ionization time-of-flight mass spectrometer: application to the measurement of gas-phase organic and inorganic acids

    Directory of Open Access Journals (Sweden)

    T. H. Bertram

    2011-03-01

    Full Text Available We report a new field-deployable chemical ionization time-of-flight mass spectrometer (CI-TOFMS for the direct measurement of trace gases in the atmosphere. We apply the technique to the measurement of gas-phase inorganic and organic acids via negative-ion proton transfer, using acetate as the reagent ion. A novel high pressure interface, incorporating two RF-only quadrupoles is used to efficiently focus ions through four stages of differential pumping before analysis with a compact TOFMS. The high ion-duty cycle (>20% of the TOFMS, coupled to efficient production and transmission of ions in the high pressure interface results in a highly sensitive (>300 ions s−1 pptv−1 instrument capable of the fast measurement of atmospheric gases at trace levels. We demonstrate the efficient transfer and detection of both bare ions and ion-molecule clusters, and characterize the instrument during field measurements aboard the R/V Atlantis as part of the CalNex campaign during the spring of 2010. The in-field short-term precision is better than 5% at 1 pptv (pL/L, for 1-second averages. The detection limit (3σ, 1-second averages of the current version of the CI-TOFMS, as applied to the in situ detection of gas-phase acids, is limited by the magnitude and variability in the background determination and was determined to be 4 pptv.

  17. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 2 covers the advances in gas phase ion chemistry. The book discusses the stabilities of positive ions from equilibrium gas-phase basicity measurements; the experimental methods used to determine molecular electron affinities, specifically photoelectron spectroscopy, photodetachment spectroscopy, charge transfer, and collisional ionization; and the gas-phase acidity scale. The text also describes the basis of the technique of chemical ionization mass spectrometry; the energetics and mechanisms of unimolecular reactions of positive ions; and the photodissociation

  18. Control of the Position of Oxygen Delivery in Soybean Lipoxygenase-1 by Amino Acid Side Chains within a Gas Migration Channel.

    Science.gov (United States)

    Collazo, Lara; Klinman, Judith P

    2016-04-22

    Understanding gas migration pathways is critical to unraveling structure-function relationships in enzymes that process gaseous substrates such as O2, H2, and N2 This work investigates the role of a defined pathway for O2 in regulating the peroxidation of linoleic acid by soybean lipoxygenase 1. Computational and mutagenesis studies provide strong support for a dominant delivery channel that shuttles molecular oxygen to a specific region of the active site, thereby ensuring the regio- and stereospecificity of product. Analysis of reaction kinetics and product distribution in channel mutants also reveals a plasticity to the gas migration pathway. The findings show that a single site mutation (I553W) limits oxygen accessibility to the active site, greatly increasing the fraction of substrate that reacts with oxygen free in solution. They also show how a neighboring site mutation (L496W) can result in a redirection of oxygen toward an alternate position of the substrate, changing the regio- and stereospecificity of peroxidation. The present data indicate that modest changes in a protein scaffold may modulate the access of small gaseous molecules to enzyme-bound substrates.

  19. A selective and sensitive method for quantitation of lysergic acid diethylamide (LSD) in whole blood by gas chromatography-ion trap tandem mass spectrometry.

    Science.gov (United States)

    Libong, Danielle; Bouchonnet, Stéphane; Ricordel, Ivan

    2003-01-01

    A gas chromatography-ion trap tandem mass spectrometry (GC-ion trap MS-MS) method for detection and quantitation of LSD in whole blood is presented. The sample preparation process, including a solid-phase extraction step with Bond Elut cartridges, was performed with 2 mL of whole blood. Eight microliters of the purified extract was injected with a cold on-column injection method. Positive chemical ionization was performed using acetonitrile as reagent gas; LSD was detected in the MS-MS mode. The chromatograms obtained from blood extracts showed the great selectivity of the method. GC-MS quantitation was performed using lysergic acid methylpropylamide as the internal standard. The response of the MS was linear for concentrations ranging from 0.02 ng/mL (detection threshold) to 10.0 ng/mL. Several parameters such as the choice of the capillary column, the choice of the internal standard and that of the ionization mode (positive CI vs. EI) were rationalized. Decomposition pathways under both ionization modes were studied. Within-day and between-day stability were evaluated.

  20. Health Care Wide Hazards

    Science.gov (United States)

    ... Other Hazards (Lack of) PPE Slips/Trips/Falls Stress Tuberculosis Universal Precautions Workplace Violence Use of Medical Lasers Health Effects Use ... Needlesticks Noise Mercury Inappropriate PPE Slips/Trips/Falls ... of Universal Precautions Workplace Violence For more information, see Other Healthcare Wide ...

  1. Hazards of Mercury.

    Science.gov (United States)

    Environmental Research, 1971

    1971-01-01

    Common concern for the protection and improvement of the environment and the enhancement of human health and welfare underscore the purpose of this special report on the hazards of mercury directed to the Secretary's Pesticide Advisory Committee, Department of Health, Education, and Welfare. The report summarizes the findings of a ten-member study…

  2. Overconfidence and Moral Hazard

    DEFF Research Database (Denmark)

    de la Rosa, Leonidas Enrique

    2011-01-01

    In this paper, I study the effects of overconfidence on incentive contracts in a moral-hazard framework. Agent overconfidence can have conflicting effects on the equilibrium contract. On the one hand, an optimistic or overconfident agent disproportionately values success-contingent payments...

  3. Cadmium - is it hazardous

    Energy Technology Data Exchange (ETDEWEB)

    Zartner-Nyilas, G.; Valentin, H.; Schaller, K.H.; Schiele, R.

    1983-01-01

    The report summarizes the state of knowledge and experience on cadmium. Biological, toxicological and epidemiological data have been evaluated. Cd pollution of the environment is reviewed under the aspect of human health. Uptake in food, threshod values of Cd exposure of the population, types and extent of health hazards, possible carcinogenic effects and future fields of research are discussed.

  4. Moral Hazard and Stability

    DEFF Research Database (Denmark)

    Tumennasan, Norovsambuu

    2014-01-01

    not form. Formally, we study the team formation problem in which the agents’ efforts are not verifiable and the size of teams does not exceed quota r . We show that if the team members cannot make transfers, then moral hazard affects stability positively in a large class of games. For example, a stable...

  5. Maintenance and hazardous substances

    NARCIS (Netherlands)

    Kuhl, K.; Terwoert, J.; Cabecas, J.J.M.

    2012-01-01

    Maintenance workers come into close contact with a broad variety of often hazardous chemicals. Depending on the specific type, these chemicals may not only cause diseases like skin sores or cancer, but many of them are highly flammable and explosive. This e-facts focuses on the specific risks relate

  6. Ethanol and Acetic Acid Production from Carbon Monoxide in a Clostridium Strain in Batch and Continuous Gas-Fed Bioreactors

    Directory of Open Access Journals (Sweden)

    Haris Nalakath Abubackar

    2015-01-01

    Full Text Available The effect of different sources of nitrogen as well as their concentrations on the bioconversion of carbon monoxide to metabolic products such as acetic acid and ethanol by Clostridium autoethanogenum was studied. In a first set of assays, under batch conditions, either NH4Cl, trypticase soy broth or yeast extract (YE were used as sources of nitrogen. The use of YE was found statistically significant (p < 0.05 on the product spectrum in such batch assays. In another set of experiments, three bioreactors were operated with continuous CO supply, in order to estimate the effect of running conditions on products and biomass formation. The bioreactors were operated under different conditions, i.e., EXP1 (pH = 5.75, YE 1g/L, EXP2 (pH = 4.75, YE 1 g/L and EXP3 (pH = 5.75, YE 0.2 g/L. When compared to EXP2 and EXP3, it was found that EXP1 yielded the maximum biomass accumulation (302.4 mg/L and products concentrations, i.e., acetic acid (2147.1 mg/L and ethanol (352.6 mg/L. This can be attributed to the fact that the higher pH and higher YE concentration used in EXP1 stimulated cell growth and did, consequently, also enhance metabolite production. However, when ethanol is the desired end-product, as a biofuel, the lower pH used in EXP2 was more favourable for solventogenesis and yielded the highest ethanol/acetic acid ratio, reaching a value of 0.54.

  7. Stability of gas-phase tartaric acid anions investigated by quantum chemistry, mass spectrometry, and infrared spectroscopy.

    Science.gov (United States)

    Tonner, Ralf; Schwerdtfeger, Peter; May, Amanda L; Steill, Jeffrey D; Berden, Giel; Oomens, Jos; Campagna, Shawn R; Compton, Robert N

    2012-05-17

    In an effort to understand the chemical factors that stabilize dianions, experimental and theoretical studies on the stability of the tartrate dianion were performed. Quantum chemical calculations at the coupled cluster level reveal only a metastable state with a possible decomposition pathway (O(2)C-CH(OH)-CH(OH)-CO(2))(2-) → (O(2)C-CH(OH)-CH(OH))(•-) + CO(2) + e(-) explaining the observed gas-phase instability of this dianion. Further theoretical data were collected for the bare dianion, this molecule complexed to water, sodium, and a proton, in both the meso and l forms as well as for the uncomplexed radical anion and neutral diradical. The calculations suggest that the l-tartrate dianion is more thermodynamically stable than the dianion of the meso stereoisomer and that either dianion can be further stabilized by association with a separate species that can help to balance the charge of the molecular complex. Mass spectrometry was then used to measure the energy needed to initiate collisionally induced dissociation of the racemic tartrate dianion and for the proton and sodium adducts of both the racemic and meso form of this molecule. Infrared action spectra of the dianion stereoisomers complexed with sodium were also acquired to determine the influence of the metal ion on the vibrations of the dianions and validate the computationally predicted structures. These experimental data support the theoretical conclusions and highlight the instability of the bare tartrate dianion. From the experimental work, it could also be concluded that the pathway leading to dissociation is under kinetic control because the sodium adduct of the racemic stereoisomer dissociated at lower collisional energy, although it was calculated to be more stable, and that decomposition proceeded via C-C bond dissociation as computationally predicted. Taken together, these data provide insight into the gas-phase stability of the tartrate dianion and highlight the role of adducts in

  8. 33 CFR 127.203 - Portable gas detectors.

    Science.gov (United States)

    2010-07-01

    ...) WATERFRONT FACILITIES WATERFRONT FACILITIES HANDLING LIQUEFIED NATURAL GAS AND LIQUEFIED HAZARDOUS GAS Waterfront Facilities Handling Liquefied Natural Gas Equipment § 127.203 Portable gas detectors. The marine... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Portable gas detectors....

  9. Comparison of Genetic Parameters Estimation of Fatty Acids from Gas Chromatography and FT-IR in Holsteins

    DEFF Research Database (Denmark)

    Poulsen, Nina Aagaard; Eskildsen, C E A; Skov, Thomas;

    Fourier transform infrared (FT-IR) is routinely used in the milk recording system and IR-based solutions are therefore attractive to ensure the full potential of genomic selection data in future breeding programs. Today, IR-based models can be used to predict a wide range of milk traits......, and their genetic parameters. However, IR-predicted phenotypes for detailed milk composition are often based on their correlation to other traits in a given data set rather than on direct predictions. Here, genetic parameters for individual milk fatty acids were estimated based on either IR-predicted phenotypes...

  10. Hazardous Waste: Learn the Basics of Hazardous Waste

    Science.gov (United States)

    Jump to main content US EPA United States Environmental Protection Agency Search Search Hazardous Waste Share Facebook Twitter ... listed or characteristic hazardous waste. Finally, it is important to note that some facilities petitioned EPA to ...

  11. Hazardous Material Storage Facilities and Sites - Commercial Hazardous Waste Operations

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — A Commercial Hazardous Waste Operation is a DEP primary facility type related to the Waste Management Hazardous Waste Program. The sub-facility types related to...

  12. A gas chromatography-mass spectrometry method for the determination of delta-aminolevulinic acid in plant leaves.

    Science.gov (United States)

    Hijaz, Faraj; Killiny, Nabil

    2016-05-20

    Delta-aminolevulinic (δ-ALA) acid is an important intermediate for tetrapyrroles biosynthesis and it has recently received great attention in plant physiology and human toxicology. However, the colorimetric method which is the most common method for determination of δ-ALA is time consuming and is not specific. In this study, a method for determination of δ-ALA in plant tissues was developed based on the trimethylsilyl (TMS) derivative of the pyrrole formed from the reaction of δ-ALA with ethyl acetoacetate via Knorr condensation. The δ-ALA in the HCl extract was reacted with ethyl acetoacetate to form a pyrrole. Then, the pyrrole compound was extracted using ethyl acetate and the solvent was evaporated to dryness. The dried sample was derivatized to its TMS ester and analyzed using GC-MS. The concentration of δ-ALA in citrus leaves incubated with levulinic acid was also determined by the conventional colorimetric method. The linear range was 10-200ppm in the full scan mode and 0.1-20ppm in the selected ion monitoring (SIM). The limit of detection was 6ppm in the full scan and 0.05ppm in SIM mode, representing a four-fold increase in sensitivity compared to the colorimetric method. The GC-MS method developed in this study is simple, accurate, sensitive, and could also be used to measure δ-ALA in other biological samples.

  13. Wet air oxidation of formic acid using nanoparticle-modified polysulfone hollow fibers as gas-liquid contactors.

    Science.gov (United States)

    Hogg, Seth R; Muthu, Satish; O'Callaghan, Michael; Lahitte, Jean-Francois; Bruening, Merlin L

    2012-03-01

    Catalytic wet air oxidation (CWAO) using membrane contactors is attractive for remediation of aqueous pollutants, but previous studies of even simple reactions such as formic acid oxidation required multiple passes through tubular ceramic membrane contactors to achieve high conversion. This work aims to increase single-pass CWAO conversions by using polysulfone (PS) hollow fibers as contactors to reduce diffusion distances in the fiber lumen. Alternating adsorption of polycations and citrate-stabilized platinum colloids in fiber walls provides catalytically active PS hollow fibers. Using a single PS fiber, 50% oxidation of a 50 mM formic acid feed solution results from a single pass through the fiber lumen (15 cm length) with a solution residence time of 40 s. Increasing the number of PS fibers to five while maintaining the same volumetric flow rate leads to over 90% oxidation, suggesting that further scale up in the number of fibers will facilitate high single pass conversions at increased flow rates. The high conversion compared to prior studies with ceramic fibers stems from shorter diffusion distances in the fiber lumen. However, the activity of the Pt catalyst is 20-fold lower than in previous ceramic fibers. Focusing the Pt deposition near the fiber lumen and limiting pore wetting to this region might increase the activity of the catalyst.

  14. Carbon isotopic ratio analysis by gas chromatography/combustion/isotope ratio mass spectrometry for the detection of gamma-hydroxybutyric acid (GHB) administration to humans.

    Science.gov (United States)

    Saudan, Christophe; Augsburger, Marc; Mangin, Patrice; Saugy, Martial

    2007-01-01

    Since GHB (gamma-hydroxybutyric acid) is naturally produced in the human body, clinical and forensic toxicologists must be able to discriminate between endogenous levels and a concentration resulting from exposure. To suggest an alternative to the use of interpretative concentration cut-offs, the detection of exogenous GHB in urine specimens was investigated by means of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). GHB was isolated from urinary matrix by successive purification on Oasis MCX and Bond Elute SAX solid-phase extraction (SPE) cartridges prior to high-performance liquid chromatography (HPLC) fractioning using an Atlantis dC18 column eluted with a mixture of formic acid and methanol. Subsequent intramolecular esterification of GHB leading to the formation of gamma-butyrolactone (GBL) was carried out to avoid introduction of additional carbon atoms for carbon isotopic ratio analysis. A precision of 0.3 per thousand was determined using this IRMS method for samples at GHB concentrations of 10 mg/L. The (13)C/(12)C ratios of GHB in samples of subjects exposed to the drug ranged from -32.1 to -42.1 per thousand, whereas the results obtained for samples containing GHB of endogenous origin at concentration levels less than 10 mg/L were in the range -23.5 to -27.0 per thousand. Therefore, these preliminary results show that a possible discrimination between endogenous and exogenous GHB can be made using carbon isotopic ratio analyses.

  15. Determination of arsenic species in solid matrices utilizing supercritical fluid extraction coupled with gas chromatography after derivatization with thioglycolic acid n-butyl ester.

    Science.gov (United States)

    Wang, Zhifeng; Cui, Zhaojie

    2016-12-01

    A method using derivatization and supercritical fluid extraction coupled with gas chromatography was developed for the analysis of dimethylarsinate, monomethylarsonate and inorganic arsenic simultaneously in solid matrices. Thioglycolic acid n-butyl ester was used as a novel derivatizing reagent. A systematic discussion was made to investigate the effects of pressure, temperature, flow rate of the supercritical CO2 , extraction time, concentration of the modifier, and microemulsion on extraction efficiency. The application for real environmental samples was also studied. Results showed that thioglycolic acid n-butyl ester was an effective derivatizing reagent that could be applied for arsenic speciation. Using methanol as modifier of the supercritical CO2 can raise the extraction efficiency, which can be further enhanced by adding a microemulsion that contains Triton X-405. The optimum extraction conditions were: 25 MPa, 90°C, static extraction for 10 min, dynamic extraction for 25 min with a flow rate of 2.0 mL/min of supercritical CO2 modified by 5% v/v methanol and microemulsion. The detection limits of dimethylarsinate, monomethylarsonate, and inorganic arsenic in solid matrices were 0.12, 0.26, and 1.1 mg/kg, respectively. The optimized method was sensitive, convenient, and reliable for the extraction and analysis of different arsenic species in solid samples.

  16. Acid-yield measurements of the gas-phase ozonolysis of ethene as a function of humidity using Chemical Ionisation Mass Spectrometry (CIMS

    Directory of Open Access Journals (Sweden)

    K. E. Leather

    2012-01-01

    Full Text Available Gas-phase ethene ozonolysis experiments were conducted at room temperature to determine formic acid yields as a function of relative humidity (RH using the integrated EXTreme RAnge chamber-Chemical Ionisation Mass Spectrometry technique, employing a CH3I ionisation scheme. RHs studied were <1, 11, 21, 27, 30 % and formic acid yields of (0.07±0.01 and (0.41±0.07 were determined at <1 % RH and 30 % RH respectively, showing a strong water dependence. It has been possible to estimate the ratio of the rate coefficient for the reaction of the Criegee biradical, CH2OO with water compared with decomposition. This analysis suggests that the rate of reaction with water ranges between 1×10−12–1×10−15 cm3 molecule−1 s−1 and will therefore dominate its loss with respect to bimolecular processes in the atmosphere. Global model integrations suggest that this reaction between CH2OO and water may dominate the production of HC(OOH in the atmosphere.

  17. Spoilage potential of psychrotrophic lactic acid bacteria (LAB) species: Leuconostoc gelidum subsp. gasicomitatum and Lactococcus piscium, on sweet bell pepper (SBP) simulation medium under different gas compositions.

    Science.gov (United States)

    Pothakos, Vasileios; Nyambi, Clarice; Zhang, Bao-Yu; Papastergiadis, Antonios; De Meulenaer, Bruno; Devlieghere, Frank

    2014-05-16

    Sweet bell peppers are a significant constituent of retail, chilled-stored and packaged food products like fresh salads, marinades and ready-to-eat (RTE) meals. Previously, through general screening of the Belgian market and by means of source tracking analysis in a plant manufacturing minimally processed, vegetable salads the susceptibility of fresh-cut sweet bell peppers to lactic acid bacterium (LAB) contamination was substantiated. The determination of the metabolic profiles of Leuconostoc gelidum subsp. gasicomitatum and Lactococcus piscium, two major psychrotrophic, spoilage-related LAB species, on sweet bell pepper (SBP) simulation medium under different packaging conditions - 1.) vacuum: 100% N2, 2.) air: 21% O2, 79% N2, 3.) MAP1: 30% CO2, 70% N2 and 4.) MAP2: 50% O2, 50% CO2 - facilitated a better understanding of the spoilage potential of these microbes as well as the presumptive contribution of O2 in the spectrum of produced volatile organic compounds (VOCs) associated with poor organoleptic properties of food products. Generally, none of the applied gas compositions inhibited the growth of the 4 L. gelidum subsp. gasicomitatum isolates, however the presence of O2 resulted in buttery off-odors by inducing primarily the accumulation of diacetyl and pungent "vinegar" smell due to acetic acid. The 3 tested isolates of L. piscium varied greatly among their growth dynamics and inhibition at MAP2. They exhibited either weak spoilage profile or very offensive metabolism confirming significant intraspecies diversity.

  18. Hazard perception in traffic. [previously knows as: Hazard perception.

    NARCIS (Netherlands)

    2008-01-01

    Hazard perception is an essential part of the driving task. There are clear indications that insufficient skills in perceiving hazards play an important role in the occurrence of crashes, especially those involving novice drivers. Proper hazard perception not only consists of scanning and perceiving

  19. EFSA BIOHAZ Panel (EFSA Panel on Biological Hazards), 2014. Scientific Opinion on the evaluation of the safety and efficacy of peroxyacetic acid solutions for reduction of pathogens on poultry carcasses and meat

    DEFF Research Database (Denmark)

    Hald, Tine; Baggesen, Dorte Lau

    Studies evaluating the safety and efficacy of solutions, containing peroxyacetic acid (PAA) as the active ingredient, in mixtures with acetic acid, hydrogen peroxide, and 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) and possibly octanoic acid and peroxyoctanoic acid, for reduction of pathogens...... include monitoring of the concentration of HEDP and of the decontaminating substance in the working solution and post-marketing surveillance for resistance in both pathogenic and commensal bacteria....

  20. Effects of crystalline menthol on blood metabolites in Holstein steers and in vitro volatile fatty acid and gas production.

    Science.gov (United States)

    Van Bibber-Krueger, C L; Miller, K A; Aperce, C C; Alvarado-Gilis, C A; Higgins, J J; Drouillard, J S

    2016-03-01

    Fifty-two Holstein steers (573 ± 9.92 kg BW) were used to determine if oral administration of crystalline menthol would induce changes in endogenous secretions of IGF-1 and circulating concentrations of glucose, lactate, and plasma urea nitrogen (PUN). Steers were blocked by BW and assigned within block to treatment. Treatments consisted of 0, 0.003, 0.03, or 0.3% crystalline menthol (DM basis) added to the diet. Animals were housed in individual, partially covered pens equipped with feed bunks and automatic water fountains. On d 1 of the experiment, blood samples were obtained via jugular venipuncture at 0, 6, 12, 18, and 24 h after feeding. Treatment administration commenced on d 2, and blood samples were again drawn at 0, 6, 12, 18, and 24 h after feeding. This blood-sampling schedule was repeated on d 9, 16, 23, and 30. Plasma was analyzed for PUN, glucose, and lactate concentrations. Serum was used to analyze IGF-1 concentration. Body weights were measured on d 1, 9, 16, 23, and 30. To accompany the live animal phase, in vitro fermentations were performed using ruminal fluid cultures. Measurements included VFA concentrations and fermentative gas production for cultures containing crystalline menthol at 0, 0.003, 0.03, or 0.3% of substrate DM. Addition of menthol to the diet of steers resulted in a treatment × day interaction ( menthol had greater serum IGF-1 concentrations on d 2 compared with steers fed 0.03% menthol. Steers fed 0% menthol had greater serum IGF-1 concentrations on d 9 compared with steers fed 0.03 and 0.3% menthol, whereas no differences were observed on d 23 or 30. Plasma glucose was similar among treatments until d 23, when steers supplemented with 0.03% menthol had lower glucose concentrations. Plasma urea nitrogen concentrations were not different among treatments; however, PUN concentrations varied by day. A linear response was detected for BW ( = 0.03), with steers consuming 0% menthol having the greatest BW and steers that consumed 0

  1. Comparison and validation of 2 analytical methods for the determination of free fatty acids in dairy products by gas chromatography with flame ionization detection.

    Science.gov (United States)

    Mannion, David T; Furey, Ambrose; Kilcawley, Kieran N

    2016-07-01

    Accurate quantification of free fatty acids (FFA) in dairy products is important for quality control, nutritional, antimicrobial, authenticity, legislative, and flavor purposes. In this study, the performance of 2 widely used gas chromatographic flame ionization detection methods for determination of FFA in dairy products differing in lipid content and degree of lipolysis were evaluated. We used a direct on-column approach where the isolated FFA extract was injected directly and a derivatization approach where the FFA were esterified in the injector to methyl esters using tetramethylammonium hydroxide as a catalyst. A comprehensive validation was undertaken to establish method linearity, limits of detection, limits of quantification, accuracy, and precision. Linear calibrations of 3 to 700mg/L (R(2)>0.999) and 20 to 700mg/L (R(2)>0.997), and limits of detection and limits of quantification of 0.7 and 3mg/L and 5 and 20mg/L were obtained for the direct injection on-column and the derivatization method, respectively. Intraday precision of 1.5 to 7.2% was obtained for both methods. The direct injection on-column method had the lower levels of limits of detection and quantification, because FFA are directly injected onto the GC as opposed to the split injection used in the derivatization method. However, the direct injection on-column method experienced accumulative column phase deterioration and irreversible FFA absorption because of the acidic nature of the injection extract, which adversely affected method robustness and the quantification of some longer chain FFA. The derivatization method experienced issues with quantification of butyric acid at low concentrations because of coelution with the injection solvent peak, loss of polyunsaturated FFA due to degradation by tetramethylammonium hydroxide, and the periodic emergence of by-product peaks of the tetramethylammonium hydroxide reaction that interfered with the quantification of some short-chain FFA. The

  2. Determination of acidic pharmaceuticals and potential endocrine disrupting compounds in wastewaters and spring waters by selective elution and analysis by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Gibson, Richard; Becerril-Bravo, Elías; Silva-Castro, Vanessa; Jiménez, Blanca

    2007-10-26

    Although the trend in development of analytical methods for emerging contaminants is towards reduced sample preparation and increased detector selectivity, there are still benefits from removal of matrix material during sample preparation. This paper describes a simple method for acidic pharmaceuticals and a range of potential endocrine disrupting compounds in untreated wastewaters and spring waters. It is based on separation of the two classes during elution from the extraction cartridge with final analysis by gas chromatography-mass spectrometry. 3,4-D was used as the recovery standard for the acids while 4-n-nonylphenol and [2H4]estrone were used for the endocrine disrupters; mean recoveries varied between 89% and 111%. The method was also extensively validated by fortification with the target compounds. Recoveries of acids were from 68% to 97% with relative standard deviations generally less than 10% and recoveries of endocrine disrupters were 68-109% with relative standard deviations less than 20%. Detection limits varied from 0.005 to 1 ng/L in spring water, and from 0.5 to 100 ng/L in untreated wastewater. Concentrations of the analytes in the wastewater ranged from 0.018 to 22.4 microg/L. Values were comparable to reported data, although concentrations were generally relatively high, probably because of a lack of treatment. Triclosan, phthalates, estrone, 17beta-estradiol, ibuprofen, and naproxen were present in the spring water from aquifers recharged indirectly with this wastewater after its use for irrigation; concentrations ranged from 0.01 to 25.0 ng/L. The much lower concentrations compared to wastewater indicate effective removal processes on passage through the soil and subsoil.

  3. Gas generation during waste treatment of acidic solutions from the dissolution of irradiated LEU targets for 99Mo production

    Energy Technology Data Exchange (ETDEWEB)

    Bakel, Allen J. [Argonne National Lab. (ANL), Argonne, IL (United States); Conner, Cliff [Argonne National Lab. (ANL), Argonne, IL (United States); Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-01-01

    The goal of the Reduced Enrichment for Research and Test Reactors Program is to limit the use of high-enriched uranium (HEU) in research and test reactors by substituting low-enriched uranium (LEU) wherever possible. The work reported here documents our work to develop the calcining technologies and processes that will be needed for 99Mo production using LEU foil targets and the Modified Cintichem Process. The primary concern with the conversion to LEU from HEU targets is that it would result in a five- to six-fold increase in the total uranium. This increase results in more liquid waste from the process. We have been working to minimize the increase in liquid waste and to minimize the impact of any change in liquid waste. Direct calcination of uranium-rich nitric acid solutions generates NO2 gas and UO3 solid. We have proposed two processes for treating the liquid waste from a Modified Cintichem Process with a LEU foil. One is an optimized direct calcination process that is similar to the process currently in use. The other is a uranyl oxalate precipitation process. The specific goal of the work reported here was to characterize and compare the chemical reactions that occur during these two processes. In particular, the amounts and compositions of the gaseous and solid products were of interest. A series of experiments was carried out to show the effects of temperature and the redox potential of the reaction atmosphere. The primary products of the direct calcination process were mixtures of U3O8 and UO3 solids and NO2 gas. The primary products of the oxalate precipitation process were mixtures of U3O8 and UO2 solid and CO2 gas. Higher temperature and a reducing atmosphere tended to favor quadrivalent over hexavalent uranium in the solid product. These data will help producers to decide between the two processes. In addition, the data can be used to design

  4. Seismic hazard maps for Haiti

    Science.gov (United States)

    Frankel, Arthur; Harmsen, Stephen; Mueller, Charles; Calais, Eric; Haase, Jennifer

    2011-01-01

    We have produced probabilistic seismic hazard maps of Haiti for peak ground acceleration and response spectral accelerations that include the hazard from the major crustal faults, subduction zones, and background earthquakes. The hazard from the Enriquillo-Plantain Garden, Septentrional, and Matheux-Neiba fault zones was estimated using fault slip rates determined from GPS measurements. The hazard from the subduction zones along the northern and southeastern coasts of Hispaniola was calculated from slip rates derived from GPS data and the overall plate motion. Hazard maps were made for a firm-rock site condition and for a grid of shallow shear-wave velocities estimated from topographic slope. The maps show substantial hazard throughout Haiti, with the highest hazard in Haiti along the Enriquillo-Plantain Garden and Septentrional fault zones. The Matheux-Neiba Fault exhibits high hazard in the maps for 2% probability of exceedance in 50 years, although its slip rate is poorly constrained.

  5. The Additive Hazard Mixing Models

    Institute of Scientific and Technical Information of China (English)

    Ping LI; Xiao-liang LING

    2012-01-01

    This paper is concerned with the aging and dependence properties in the additive hazard mixing models including some stochastic comparisons.Further,some useful bounds of reliability functions in additive hazard mixing models are obtained.

  6. FEMA DFIRM Flood Hazard Areas

    Data.gov (United States)

    Minnesota Department of Natural Resources — FEMA flood hazard delineations are used by the Federal Emergency Management Agency (FEMA) to designate the Special Flood Hazard Area (SFHA) and for insurance rating...

  7. Industrial hazard and safety handbook

    CERN Document Server

    King, Ralph W

    1979-01-01

    Industrial Hazard and Safety Handbook (Revised Impression) describes and exposes the main hazards found in industry, with emphasis on how these hazards arise, are ignored, are identified, are eliminated, or are controlled. These hazard conditions can be due to human stresses (for example, insomnia), unsatisfactory working environments, as well as secret industrial processes. The book reviews the cost of accidents, human factors, inspections, insurance, legal aspects, planning for major emergencies, organization, and safety measures. The text discusses regulations, codes of practice, site layou

  8. 33 CFR 127.1203 - Gas detection.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Gas detection. 127.1203 Section... Waterfront Facilities Handling Liquefied Hazardous Gas Equipment § 127.1203 Gas detection. (a) Each... LHG that transfers a toxic LHG, other than anhydrous ammonia, must have at least two portable...

  9. The Siding Spring Hazard at Mars

    Science.gov (United States)

    Kelley, Michael; Bauer, James; Bodewits, Dennis; Farnham, Tony; Li, Jian-Yang; Samarasinha, Nalin; Stevenson, Rachel; Tricarico, Pasquale

    2014-02-01

    Comet C/2013 A1 (Siding Spring) will pass Mars at the extremely close distance of 136,000 km in Oct 2014, giving Mars orbiting spacecraft an up-close and unprecedented view of this dynamically new comet. However, 100 minutes after the closest approach to the nucleus, Mars passes within 30,000 km of the comet's orbit. Here, large dust grains may be found on impacting trajectories, potentially posing a fatal hazard to the spacecraft. Such large grains must be ejected from the comet nucleus well before the time of encounter. Therefore, we propose IRAC imaging of this comet to assess the present-day gas production rate, which will aid dust impact hazard assessment.

  10. Hazardous waste sites

    Energy Technology Data Exchange (ETDEWEB)

    Hembra, R.L

    1989-01-01

    This report has found that while most states have accomplished few or no cleanups of sites contaminated by hazardous waste, some have enacted tough cleanup laws, committed relatively large resources to the cleanup effort, and achieved considerable results. At the 17 cleanup sites analyzed, state cleanup plans were generally stringent. However, no federal standards have been set for over half of the contaminants found at these sites. For 11 sites, the states set cleanup levels without doing formal risk assessments. Also, most states reviewed did not consider the full range of alternatives EPA requires. Most states have not shown that they can effectively clean up large, hazardous waste sites. This report recommends that EPA turn sites targeted for cleanup over to the states only if there are adequate controls and oversight.

  11. 77 FR 17573 - Hazard Communication

    Science.gov (United States)

    2012-03-26

    ..., 1915 and 1926 Hazard Communication; Final Rule #0;#0;Federal Register / Vol. 77 , No. 58 / Monday... Administration 29 CFR Parts 1910, 1915, and 1926 RIN 1218-AC20 Hazard Communication AGENCY: Occupational Safety... modifying its Hazard Communication Standard (HCS) to conform to the United Nations' Globally...

  12. Hazard Maps in the Classroom.

    Science.gov (United States)

    Cross, John A.

    1988-01-01

    Emphasizes the use of geophysical hazard maps and illustrates how they can be used in the classroom from kindergarten to college level. Depicts ways that hazard maps of floods, landslides, earthquakes, volcanoes, and multi-hazards can be integrated into classroom instruction. Tells how maps may be obtained. (SLM)

  13. PUREX facility hazards assessment

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, L.N.

    1994-09-23

    This report documents the hazards assessment for the Plutonium Uranium Extraction Plant (PUREX) located on the US Department of Energy (DOE) Hanford Site. Operation of PUREX is the responsibility of Westinghouse Hanford Company (WHC). This hazards assessment was conducted to provide the emergency planning technical basis for PUREX. DOE Order 5500.3A requires an emergency planning hazards assessment for each facility that has the potential to reach or exceed the lowest level emergency classification. In October of 1990, WHC was directed to place PUREX in standby. In December of 1992 the DOE Assistant Secretary for Environmental Restoration and Waste Management authorized the termination of PUREX and directed DOE-RL to proceed with shutdown planning and terminal clean out activities. Prior to this action, its mission was to reprocess irradiated fuels for the recovery of uranium and plutonium. The present mission is to establish a passively safe and environmentally secure configuration at the PUREX facility and to preserve that condition for 10 years. The ten year time frame represents the typical duration expended to define, authorize and initiate follow-on decommissioning and decontamination activities.

  14. Efficient gas barrier properties of multi-layer films based on poly(lactic acid) and fish gelatin.

    Science.gov (United States)

    Hosseini, Seyed Fakhreddin; Javidi, Zahra; Rezaei, Masoud

    2016-11-01

    Multi-layer film structures of poly(lactic acid) (PLA) and fish gelatin (FG), prepared using the solvent casting technique, were studied in an effort to produce bio-based films with low oxygen (OP) and water vapor permeability (WVP). The scanning electron microscopy (SEM) images of triple-layer film showed that the outer PLA layers are being closely attached to the inner FG layer to make continuous film. The OP of multi-layer film (5.02cm(3)/m(2)daybar) decreased more than 8-fold compared with that of the PLA film, and the WVP of multi-layer film (0.125gmm/kPah m(2)) also decreased 11-fold compared with that of the FG film. Lamination with PLA profoundly increased the water resistance of the bare gelatin film. Meanwhile, the tensile strength of the triple-layer film (25±2.13MPa) was greater than that of FG film (7.48±1.70MPa). At the same time, the resulting film maintains high optical clarity. Differential scanning calorimetry (DSC) analysis also revealed that the materials were compatible showing only one Tg which decreased with FG deposition. This material exhibits an environmental-friendliness potential and a high versatility in food packaging.

  15. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  16. Environmental screening of acidic compounds based on capillary zone electrophoresis/laser-induced fluorescence detection with identification by gas chromatography/mass spectrometry and gas chromatography/high-resolution mass spectrometry.

    Science.gov (United States)

    Brumley, W C; Grange, A H; Kelliher, V; Patterson, D B; Montcalm, A; Glassman, J; Farley, J W

    2000-01-01

    This paper describes the application of capillary zone electrophoresis/laser-induced fluorescence detection (CZE/LIF) to the discovery of acidic compounds in environmental matrixes or the screening of extracts for acidic components. Published studies indicate that coal-derived materials contain a significant fraction of acidic compounds relative to materials derived from petroleum and shales. Such compounds may be useful as marker compounds for site assessment and source apportionment issues, and their identification may be important in toxicological and other health issues. We used deep-UV light from the frequency-doubled Ar ion laser at 244 and 257 nm to study extracts of samples. The CZE/LIF technique possesses good sensitivity and therefore overcomes one of the limitations of CZE with UV detection. The present work depends on high pressure/temperature solvent extraction of polynuclear aromatic hydrocarbon (PNA)-contaminated soil, followed by separation using CZE. The anionic analytes were separated by using borate or phosphate buffer (pH 9.2-12.3) after a chemical class separation. Samples were also characterized by gas chromatography/mass spectrometry (GC/MS) using full scans at low resolution, and elemental compositions were determined unequivocally by GC/high-resolution MS (GC/HRMS) using mass peak profiling (MPP). The similarity of low-resolution electron ionization mass spectra for a standard, 1-hydroxypyrene, and for a series of compounds in a contaminated-soil extract suggested that several types of phenolic and hydroxy-PNAs were present, including hydroxylated derivatives of fluorenes, fluoranthenes, and pyrenes. GC/HRMS using MPP confirmed the elemental compositions of the hydroxyfluorenes and hydroxypyrenes (and presumably hydroxyfluoranthenes) as [C13H10O] and [C16H10O], respectively. A new version of the MPP software was written for the Finnigan-MAT 900S-Trap and was similar to that developed previously for the VG 250SE. Inclusion of a calibration

  17. Blood pressure, acid-base and blood gas status and indicators of oxidative stress in healthy male rats exposed to acute hyperbaric oxygenation.

    Science.gov (United States)

    Drenjancevic, Ines; Kibel, Aleksandar; Kibel, Dijana; Seric, Vatroslav; Cosic, Anita

    2013-01-01

    Different protocols of hyperbaric oxygenation (HBO2) are used for research purposes; however, data on the changes in blood pressure, oxidative stress and acid-base and gas status induced by various oxygenation protocols are scarce and conflicting. The aim of this study was to examine the effects of an acute session of HBO2 [2 bar (200 kPa) for two hours] on arterial systolic and diastolic blood pressure, arterial blood gases and acid-base status, and oxidative stress in rats. Sprague-Dawley rats (12-15 weeks) were examined prior to, immediately and 24 hours after a two-hour HBO2 exposure at 2 bars. The femoral artery was cannulated to determine blood pressure, and blood samples were collected to measure blood gases and acid-base status, Ferric reducing antioxidant power ability of plasma (FRAP) and thiobarbituric acid reactive substances (TBARS). Immediately after HBO2 systolic and diastolic blood pressure significantly decreased (from 138 +/- 14/103 +/- 13 to 113 +/- 12/72 +/- 16 mmHg). However, these values were still inside the normal physiological range. pH decreased (from 7.34 +/- 0.05 to 7.28 +/- 0.05), pCO2 decreased (from 7.07 +/- 0.89 to 5.76 +/- 0.50 kPa), pO2 increased (from 12.48 +/- 0.88 to 13.68 +/- 2.4 kPa), plasma bicarbonate decreased (from 27.04 +/- 3.25 to 20.52 +/- 3.02 mmol/L). Exposure to HBO2 immediately increased TBARS levels (from 0.17 +/- 0.09 to 21.79 +/- 1.05 microM/MDA), while FRAP levels were not significantly changed. Measurements on separate animals 24 hours after a single HBO2 exposure showed no differences in comparison to control animals, except for pO2, which was significantly lower (11.10 +/- 0.31 kPa). The results define values of important parameters, serving as a necessary basis for complex analysis of HBO2 effects in research on rat animal models.

  18. 77 FR 2126 - Pipeline Safety: Implementation of the National Registry of Pipeline and Liquefied Natural Gas...

    Science.gov (United States)

    2012-01-13

    ... Registry of Pipeline and Liquefied Natural Gas Operators AGENCY: Pipeline and Hazardous Materials Safety... registry of pipeline and liquefied natural gas operators. FOR FURTHER INFORMATION CONTACT: Jamerson Pender... 72878), titled: ``Pipeline Safety: Updates to Pipeline and Liquefied Natural Gas Reporting...

  19. Gas-phase structures of Pb(2+)-cationized phenylalanine and glutamic acid determined by infrared multiple photon dissociation spectroscopy and computational chemistry.

    Science.gov (United States)

    Burt, Michael B; Fridgen, Travis D

    2013-02-14

    Infrared multiple photon dissociation (IRMPD) spectroscopy in the 3200-3800 cm(-1) region was used to determine the gas-phase structures of bare and monohydrated [Pb(Phe-H)](+) and [Pb(Glu-H)](+). These experiments were supported by infrared spectra calculated at the B3LYP/6-31+G(d,p) level of theory as well as 298 K enthalpies and Gibbs energies determined using the MP2(full)/6-311++G(2d,2p)//B3LYP/6-31+G(d,p) method. The gas-phase structure of [Pb(Phe-H)](+) has Pb(2+) bound in a tridentate fashion between Phe's amine nitrogen, one oxygen of the deprotonated carboxyl group, and the aromatic ring. The IRMPD spectrum of [Pb(Glu-H)](+) can be assigned to a structure where the side chain carboxyl group is deprotonated. The structure of [Pb(Phe-H)H(2)O](+) is simply the hydrated analogue of [Pb(Phe-H)](+) where water attaches to Pb(2+) in the same hemisphere as the ligated amino acid. The spectrum of [Pb(Glu-H)H(2)O](+) could not be assigned a unique structure. The IRMPD spectrum shows features attributed to symmetric and antisymmetric O-H stretching of water and a broad band characteristic of a hydrogen bonded O-H stretching vibration. These features can only be explained by the presence of at least two isomers and agree with the computational results that predict the four lowest energy structures to be within 6 kJ mol(-1) of one another.

  20. Anaesthesia machine: checklist, hazards, scavenging.

    Science.gov (United States)

    Goneppanavar, Umesh; Prabhu, Manjunath

    2013-09-01

    From a simple pneumatic device of the early 20(th) century, the anaesthesia machine has evolved to incorporate various mechanical, electrical and electronic components to be more appropriately called anaesthesia workstation. Modern machines have overcome many drawbacks associated with the older machines. However, addition of several mechanical, electronic and electric components has contributed to recurrence of some of the older problems such as leak or obstruction attributable to newer gadgets and development of newer problems. No single checklist can satisfactorily test the integrity and safety of all existing anaesthesia machines due to their complex nature as well as variations in design among manufacturers. Human factors have contributed to greater complications than machine faults. Therefore, better understanding of the basics of anaesthesia machine and checking each component of the machine for proper functioning prior to use is essential to minimise these hazards. Clear documentation of regular and appropriate servicing of the anaesthesia machine, its components and their satisfactory functioning following servicing and repair is also equally important. Trace anaesthetic gases polluting the theatre atmosphere can have several adverse effects on the health of theatre personnel. Therefore, safe disposal of these gases away from the workplace with efficiently functioning scavenging system is necessary. Other ways of minimising atmospheric pollution such as gas delivery equipment with negligible leaks, low flow anaesthesia, minimal leak around the airway equipment (facemask, tracheal tube, laryngeal mask airway, etc.) more than 15 air changes/hour and total intravenous anaesthesia should also be considered.

  1. Anaesthesia machine: Checklist, hazards, scavenging

    Directory of Open Access Journals (Sweden)

    Umesh Goneppanavar

    2013-01-01

    Full Text Available From a simple pneumatic device of the early 20 th century, the anaesthesia machine has evolved to incorporate various mechanical, electrical and electronic components to be more appropriately called anaesthesia workstation. Modern machines have overcome many drawbacks associated with the older machines. However, addition of several mechanical, electronic and electric components has contributed to recurrence of some of the older problems such as leak or obstruction attributable to newer gadgets and development of newer problems. No single checklist can satisfactorily test the integrity and safety of all existing anaesthesia machines due to their complex nature as well as variations in design among manufacturers. Human factors have contributed to greater complications than machine faults. Therefore, better understanding of the basics of anaesthesia machine and checking each component of the machine for proper functioning prior to use is essential to minimise these hazards. Clear documentation of regular and appropriate servicing of the anaesthesia machine, its components and their satisfactory functioning following servicing and repair is also equally important. Trace anaesthetic gases polluting the theatre atmosphere can have several adverse effects on the health of theatre personnel. Therefore, safe disposal of these gases away from the workplace with efficiently functioning scavenging system is necessary. Other ways of minimising atmospheric pollution such as gas delivery equipment with negligible leaks, low flow anaesthesia, minimal leak around the airway equipment (facemask, tracheal tube, laryngeal mask airway, etc. more than 15 air changes/hour and total intravenous anaesthesia should also be considered.

  2. Volcanic gas

    Science.gov (United States)

    McGee, Kenneth A.; Gerlach, Terrance M.

    1995-01-01

    In Roman mythology, Vulcan, the god of fire, was said to have made tools and weapons for the other gods in his workshop at Olympus. Throughout history, volcanoes have frequently been identified with Vulcan and other mythological figures. Scientists now know that the “smoke" from volcanoes, once attributed by poets to be from Vulcan’s forge, is actually volcanic gas naturally released from both active and many inactive volcanoes. The molten rock, or magma, that lies beneath volcanoes and fuels eruptions, contains abundant gases that are released to the surface before, during, and after eruptions. These gases range from relatively benign low-temperature steam to thick hot clouds of choking sulfurous fume jetting from the earth. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other volcanic gases are hydrogen sulfide, hydrochloric acid, hydrogen, carbon monoxide, hydrofluoric acid, and other trace gases and volatile metals. The concentrations of these gas species can vary considerably from one volcano to the next.

  3. Versatile microanalytical system with porous polypropylene capillary membrane for calibration gas generation and trace gaseous pollutants sampling applied to the analysis of formaldehyde, formic acid, acetic acid and ammonia in outdoor air.

    Science.gov (United States)

    Coelho, Lúcia H G; Melchert, Wanessa R; Rocha, Flavio R; Rocha, Fábio R P; Gutz, Ivano G R

    2010-11-15

    The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the μg m(-3) range) and their variations with sampling site and time. In this work, a capillary membrane diffusion scrubber (CMDS) was scaled down to match with capillary electrophoresis (CE), a quick separation technique that requires nothing more than some nanoliters of sample and, when combined with capacitively coupled contactless conductometric detection (C(4)D), is particularly favorable for ionic species that do not absorb in the UV-vis region, like the target analytes formaldehyde, formic acid, acetic acid and ammonium. The CMDS was coaxially assembled inside a PTFE tube and fed with acceptor phase (deionized water for species with a high Henry's constant such as formaldehyde and carboxylic acids, or acidic solution for ammonia sampling with equilibrium displacement to the non-volatile ammonium ion) at a low flow rate (8.3 nL s(-1)), while the sample was aspirated through the annular gap of the concentric tubes at 2.5 mL s(-1). A second unit, in all similar to the CMDS, was operated as a capillary membrane diffusion emitter (CMDE), generating a gas flow with know concentrations of ammonia for the evaluation of the CMDS. The fluids of the system were driven with inexpensive aquarium air pumps, and the collected samples were stored in vials cooled by a Peltier element. Complete protocols were developed for the analysis, in air, of NH(3), CH(3)COOH, HCOOH and, with a derivatization setup, CH(2)O, by associating the CMDS collection with the determination by CE-C(4)D. The ammonia concentrations obtained by electrophoresis were checked against the reference spectrophotometric method based on Berthelot's reaction. Sensitivity enhancements of this reference method were achieved by using a modified Berthelot reaction, solenoid micro-pumps for liquid propulsion and a long optical path cell based on a liquid core waveguide (LCW). All

  4. Analysis of Conjugated Linoleic Acid Isomers by Gas Chromatography%气相色谱法定量分析共轭亚油酸异构体

    Institute of Scientific and Technical Information of China (English)

    王伟; 杨虹; 杨天奎

    2012-01-01

    Conjugated linoleic acids (CLA) are the positional and geometric isomers of linoleic acid,among them,9 c,11t-CLA and 10 t,12 c-CLA exhibited the stronger biological activity. In this study,a method was developed for the quantitative determination of 9 c, 11t-CLA and 10 t, 12 c-CLA by capillary gas chromatography. The sample of CLA oil was methylated with KOH in methanol.The calculation of results was carried out with external standards. The recovery of 9c, 11t-CLA and,10 t,12 c-CLA was between 97.66%-103.51% ,96.12%-102.48% , respectively. The detection and quantitation limits were separately 2.4 mg/kg and 8 mg/kg.%共轭亚油酸(CLA)是亚油酸的位置和几何异构体.其中9c,11t-CLA和10t,12c-CLA是目前发现生理活性比较强的两种共轭结构.作者使用氢氧化钾甲醇溶液对油脂中的共轭亚油酸甘三酯进行水解和甲酯化,利用毛细管气相色谱进行分离后外标法定量.作者得到共轭亚油酸9c,11t-CLA回收率在97.66%~ 103.51%之间,10t,12c-CLA回收率在96.12%~ 102.48%之间,检出限2.4 mg/kg,定量限8 mg/kg.

  5. Living with geo-resources and geo-hazards

    NARCIS (Netherlands)

    Hangx, Suzanne; Niemeijer, André

    2015-01-01

    Two of the key strategic topics on the European Committee’s Horizon2020 Roadmap revolve around geo-resources and geo-hazards, and their impact on societal and economic development. On the way towards a better policy for sustainable geo-resources production, such as oil, gas, geothermal energy and gr

  6. Hydrogen Storage in the Carbon Dioxide - Formic Acid Cycle.

    Science.gov (United States)

    Fink, Cornel; Montandon-Clerc, Mickael; Laurenczy, Gabor

    2015-01-01

    This year Mankind will release about 39 Gt carbon dioxide into the earth's atmosphere, where it acts as a greenhouse gas. The chemical transformation of carbon dioxide into useful products becomes increasingly important, as the CO(2) concentration in the atmosphere has reached 400 ppm. One approach to contribute to the decrease of this hazardous emission is to recycle CO(2), for example reducing it to formic acid. The hydrogenation of CO(2) can be achieved with a series of catalysts under basic and acidic conditions, in wide variety of solvents. To realize a hydrogen-based charge-discharge device ('hydrogen battery'), one also needs efficient catalysts for the reverse reaction, the dehydrogenation of formic acid. Despite of the fact that the overwhelming majority of these reactions are carried out using precious metals-based catalysts (mainly Ru), we review here developments for catalytic hydrogen evolution from formic acid with iron-based complexes.

  7. Flammable Gas Safety Self-Study 52827

    Energy Technology Data Exchange (ETDEWEB)

    Glass, George [Los Alamos National Laboratory

    2016-03-17

    This course, Flammable Gas Safety Self-Study (COURSE 52827), presents an overview of the hazards and controls associated with commonly used, compressed flammable gases at Los Alamos National Laboratory (LANL).

  8. Survey of knowledge of hazards of chemicals potentially associated with the advanced isotope separation processes

    Energy Technology Data Exchange (ETDEWEB)

    Chester, R.O.; Kirkscey, K.A.; Randolph, M.L.

    1979-09-01

    Hazards of chemical potentially associated with the advanced isotope separation processes are estimated based on open literature references. The tentative quantity of each chemical associated with the processes and the toxicity of the chemical are used to estimate this hazard. The chemicals thus estimated to be the most potentially hazardous to health are fluorine, nitric acid, uranium metal, uranium hexafluoride, and uranium dust. The estimated next most hazardous chemicals are bromine, hydrobromic acid, hydrochloric acid, and hydrofluoric acid. For each of these chemicals and for a number of other process-associated chemicals the following information is presented: (1) any applicable standards, recommended standards and their basis; (2) a brief discussion to toxic effects including short exposure tolerance, atmospheric concentration immediately hazardous to life, evaluation of exposures, recommended control procedures, chemical properties, and a list of any toxicology reviews; and (3) recommendations for future research.

  9. Gas-saturated solution process to obtain microcomposite particles of alpha lipoic acid/hydrogenated colza oil in supercritical carbon dioxide.

    Science.gov (United States)

    Mishima, Kenji; Honjo, Masatoshi; Sharmin, Tanjina; Ito, Shota; Kawakami, Ryo; Kato, Takafumi; Misumi, Makoto; Suetsugu, Tadashi; Orii, Hideaki; Kawano, Hiroyuki; Irie, Keiichi; Sano, Kazunori; Mishima, Kenichi; Harada, Takunori; Ouchi, Mikio

    2016-09-01

    Alpha lipoic acid (ALA), an active substance in anti-aging products and dietary supplements, need to be masked with an edible polymer to obscure its unpleasant taste. However, the high viscosity of the ALA molecules prevents them from forming microcomposites with masking materials even in supercritical carbon dioxide (scCO2). Therefore, the purpose of this study was to investigate and develop a novel production method for microcomposite particles for ALA in hydrogenated colza oil (HCO). Microcomposite particles of ALA/HCO were prepared by using a novel gas-saturated solution (PGSS) process in which the solid-dispersion method is used along with stepwise temperature control (PGSS-STC). Its high viscosity prevents the formation of microcomposites in the conventional PGSS process even under strong agitation. Here, we disperse the solid particles of ALA and HCO in scCO2 at low temperatures and change the temperature stepwise in order to mix the melted ALA and HCO in scCO2. As a result, a homogeneous dispersion of the droplets of ALA in melted HCO saturated with CO2 is obtained at high temperatures. After the rapid expansion of the saturated solution through a nozzle, microcomposite particles of ALA/HCO several micrometers in diameter are obtained.

  10. Collection of VLE data for acid gas - alkanolamine systems using Fourier transform infrared spectroscopy. Final report, September 29, 1990--September 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Bullin, J.A.; Rogers, W.J.

    1996-11-01

    This report describes research from September 29, 1990 through September 30, 1996, involving the development a novel Fourier transform infrared (FTIR) spectroscopic apparatus and method for measuring vapor - liquid equilibrium (VLE) systems of carbon dioxide and hydrogen sulfide with aqueous alkanolamine solutions. The original apparatus was developed and modified as it was used to collect VLE data on acid gas systems. Vapor and liquid calibrations were performed for spectral measurements of hydrogen sulfide and carbon dioxide in the vapor and in solution with aqueous diethanolamine (DEA) and methyldiethanolamine (MDEA). VLE measurements were made of systems of hydrogen sulfide and carbon dioxide in 20 wt % DEA at 50{degrees}C and 40{degrees}C. VLE measurements were made of systems of hydrogen sulfide and carbon dioxide in 50 wt% and 23 wt% MDEA at 40{degrees}C and in 23 wt% MDEA at 50{degrees}C. VLE measurements were made of systems of hydrogen sulfide and carbon dioxide in 35 wt% MDEA + 5 wt% DEA and in 35 wt% MDEA + 10 wt% DEA at 40{degrees}C and 50{degrees}C. Measurements were made of residual amounts of carbon dioxide in each VLE system. The new FTIR spectrometer is now a consistently working and performing apparatus.

  11. Catalytic hydroprocessing of SRC-II heavy distillate fractions: Conversion of the acidic fractions characterized by gas chromatography/mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Grandy, D.W.; Petrakis, L.; Li, C.; Gates, B.C.

    1986-01-01

    Kinetics data have been determined for the catalytic hydroprocessing of the acidic fractions of a heavy distillate of a liquid derived from Powhatan No. 5 coal. A commercial, sulfided Ni-Mo/..gamma..-Al/sub 2/O/sub 3/ catalyst was used in the experiments, carried out at 350/sup 0/C and 120 atm with the coal liquid fractions dissolved in cyclohexane. The feed and hydrotreated products were analyzed by gas chromatography/mass spectrometry. The data were analyzed with group-type methods for compound classes, and results were also obtained for some individual organooxygen compounds. Catalytic hydroprocessing leads to a large increase in the number of compounds and a shift to lower boiling ranges. The data are broadly consistent with reaction networks determined with pure compounds; the most important reactions include aromatic ring hydrogenation, hydrodeoxygenation, and hydrodemethylation. Pseudo-first-order rate constants for conversion of the predominant organooxygen coupounds are on the order of 10/sup -4/ L/(g of catalysts); the reactivity decreases in the order cyclohexylphenol > dimethylhydroxyindan > tetrahydronaphthol > phenylphenol > 1-naphthol.

  12. ASSESSMENT OF HEMATOLOGICAL PARAMETERS, ACID-BASE STATUS AND ARTERIAL BLOOD GAS TEST BEFORE AND AFTER TREATMENT OF ACUTE BRONCHIOLITIS IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Zuvdija Cecunjanin

    2016-08-01

    Full Text Available Objective: The purpose of our retrospective study was to investigate the necessity of some laboratory testing in patients with acute bronchiolitis before and after treatment. Methods: We have taken blood samples of all children puncturing the cubital vein, and analyzed it using the Colter appliances-automatic counter blood count, for analyzes of a number of erythrocytes, leukocytes, platelets, differential blood count, Hct, Hb. CRP concentration in serum of patients determined by laser nephelometry with CardioPhase® high sensitivity C-reactive protein (hsCRP. For assessment of acid-base status and arterial blood gas analysis were used ABL5 and ABL700 Radiometer Copenhagen. We monitored the following parameters: pH, pCO2, HCO3-, total CO2, base excess, pO2, SpO2. Results: There was a significant improvement of hypoxemia after management of acute bronchiolitis in the form of a significant increase in average values of pO2 and SpO2 after treatment of acute bronchiolitis. The average value of the number of leukocytes and value of CRP in children were significantly decreased before and after management of acute bronchiolitis. There was no significant difference in duration of hospitalization in term and preterm newborns. Conclusion: No routine diagnostic tests are used routinely. However, there is an improvement of hypoxemia after management of acute bronchiolitis in children.

  13. Critical assessment of inverse gas chromatography as means of assessing surface free energy and acid-base interaction of pharmaceutical powders.

    Science.gov (United States)

    Telko, Martin J; Hickey, Anthony J

    2007-10-01

    Inverse gas chromatography (IGC) has been employed as a research tool for decades. Despite this record of use and proven utility in a variety of applications, the technique is not routinely used in pharmaceutical research. In other fields the technique has flourished. IGC is experimentally relatively straightforward, but analysis requires that certain theoretical assumptions are satisfied. The assumptions made to acquire some of the recently reported data are somewhat modified compared to initial reports. Most publications in the pharmaceutical literature have made use of a simplified equation for the determination of acid/base surface properties resulting in parameter values that are inconsistent with prior methods. In comparing the surface properties of different batches of alpha-lactose monohydrate, new data has been generated and compared with literature to allow critical analysis of the theoretical assumptions and their importance to the interpretation of the data. The commonly used (simplified) approach was compared with the more rigorous approach originally outlined in the surface chemistry literature.

  14. Effect of H2S and COS in the fuel gas on the performance of ambient pressure phosphoric acid fuel cells

    Science.gov (United States)

    Ross, P. N., Jr.

    1985-04-01

    The objective of this project was to determine in laboratory cells the tolerance of phosphoric acid fuel cells (PAFC) to hydrogen sulfide and carbonyl sulphide impurities in the anode feed gas. The study was conducted in three phases: the first was testing in a small (1 sq cm) free electrolyte cell to examine the effect of electrode structure on cell tolerance and to determine the order of magnitude of sulfur causing failure in cells at zero utilization; the second was testing in standard 2' x 2' PAFC laboratory hardware at ambient pressure to examine the effect of hydrogen utilization on tolerance and the possible effect of fuel impurities on cathode performance; the final phase was testing with a 2' x 2' cell in a pressure vessel to determine the effect of pressurized operation on cell tolerance. The poisoning effect of hydrogen sulfide was characteristically different from the effects of carbon monoxide, in that it was not manifested by a marginal (e.g., 0 to 50 mV) increase in anode potential but either had no effect or caused catastrophic polarization. Critical levels were derived for hydrogen sulfide as related to cell operating conditions.

  15. Prediction of capillary gas chromatographic retention times of fatty acid methyl esters in human blood using MLR, PLS and back-propagation artificial neural networks.

    Science.gov (United States)

    Gupta, Vinod Kumar; Khani, Hadi; Ahmadi-Roudi, Behzad; Mirakhorli, Shima; Fereyduni, Ehsan; Agarwal, Shilpi

    2011-01-15

    Quantitative structure-retention relationship (QSRR) models correlating the retention times of fatty acid methyl esters in high resolution capillary gas chromatography and their structures were developed based on non-linear and linear modeling methods. Genetic algorithm (GA) was used for the selection of the variables that resulted in the best-fitted models. Gravitational index (G2), number of cis double bond (NcDB) and number of trans double bond (NtDB) were selected among a large number of descriptors. The selected descriptors were considered as inputs for artificial neural networks (ANNs) with three different weights update functions including Levenberg-Marquardt backpropagation network (LM-ANN), BFGS (Broyden, Fletcher, Goldfarb, and Shanno) quasi-Newton backpropagation (BFG-ANN) and conjugate gradient backpropagation with Polak-Ribiére updates (CGP-ANN). Computational result indicates that the LM-ANN method has better predictive power than the other methods. The model was also tested successfully for external validation criteria. Standard error for the training set using LM-ANN was SE=0.932 with correlation coefficient R=0.996. For the prediction and validation sets, standard error was SE=0.645 and SE=0.445 and correlation coefficient was R=0.999 and R=0.999, respectively. The accuracy of 3-2-1 LM-ANN model was illustrated using leave multiple out-cross validations (LMO-CVs) and Y-randomization.

  16. Health hazard evaluation report HETA 93-0501-2580, Western Zirconium, Ogden, Utah

    Energy Technology Data Exchange (ETDEWEB)

    Husberg, B.; Berardinelli, S.

    1996-05-01

    In response to an employee request, an investigation was begun into possible hazardous working conditions at Western Zirconium, Ogden, Utah. The requestor expressed concern over work related asthma and respiratory problems reported among employees at the facility. The company employed 430 workers at the site in the production of zirconium metal parts for use in nuclear power reactors. Records indicated occupational overexposure to hydrogen-chloride and chlorine gas and the sporadic release of hydrofluoric-acid. Spirometry data indicated that five current workers at the site had significant cross sectional changes in their spirometry. Five current workers had longitudinal changes in their spirometry and four had both cross sectional and longitudinal changes. The authors conclude that there was a potential for occupational exposure to respiratory irritants.

  17. 基于FDS的海洋平台油气处理系统火灾危险分析%Fire hazard analysis on oil & gas processing system on the offshore platform based on FDS

    Institute of Scientific and Technical Information of China (English)

    郭杰; 朱渊; 陈国明

    2011-01-01

    以某海洋平台下层甲板油气处理系统为研究对象,针对油气处理系统原油泄漏引发的火灾事故,以计算流体力学为理论基础,采用FDS软件建立油气处理系统火灾动力学模型,选取温度、热辐射强度、烟气层高度(厚度)和能见度等4个火灾危险性评价指标,对火灾影响后果进行了评价.油气处理系统一旦发生火灾将导致严重后果,人员需立即疏散并采取控制措施;通过对比不同脱险梯道受火灾影响程度,确定出了最有利于人员疏散的路径;设备泄漏孔径越大,火灾危险性越大,不利于人员疏散.%To study the fire accidents happened in the oil & gas processing system of offshore plat form due to oil discharge, a fire dynamic model is built by using FDS software, which is based on computational fluid dynamics. Four criteria including temperature, radiation intensity, smoke layer height (thickness) and visibility are used to assess the consequences of the fire. It is shown that the fire resulting from the oil &. gas processing system is so dangerous that people should be evacuated and control measured should he taken immediately. The prime escape route is determined by comparing the damages to the escape routs caused by the fire. And with the growth of the lesk aperture, the fire is more danger ous and people's evacuation is more difficult.

  18. 碱吸收法对酸性气体的处理效能研究%The research of treatment efficiency on acid gas with alkali absorption method

    Institute of Scientific and Technical Information of China (English)

    杨宏远; 齐永红; 刘彦婷

    2012-01-01

    介绍了根除炼油厂酸性气体污染问题的方法。具体实施方法是,以酸性气为原料,通过碱液吸收、精制提纯后,生产液体硫氢化钠产品。经过试生产,硫氢化钠产品完全满足国家标准中产品的各项指标,实现了酸性气体零排放。该工艺技术成熟、投资省、无二次污染,实现了炼油厂酸性气的资源化利用。%The method of eradicating the pollution from refinery acidic gas is introduced. The specific implementation method is using the acidic gas as raw material, through the absorption, products refined after the purification, production of the liquid sodium hydrosul- fide. Through trial production, all indexes of sodium hydrosulfidc productions can fully meet the national standard, and acid gases also achieved zero emissions. The process is a mature technology and low investment, no secondary pollution, realizes the resource utilization of refinery acid gas.

  19. Measurement of Organic Acids Produced By The Gas-Phase Ozonolysis of Simple Olefins Using Chemical Ionization Mass Spectrometry (CIMS) as a Function of Temperature And Humidity

    Science.gov (United States)

    Percival, C. J.; Bacak, A.; Leather, K. E.; McGillen, M. R.

    2009-12-01

    Non-methane hydrocarbons (NMHCs) form an important trace component of the atmosphere and are of particular environmental interest because of their deleterious effects on air quality, their numerous (and potentially counteractive) effects on Earth’s climate system and their sophisticated semiochemical roles in the world’s ecosystems. NMHCs are also important precursors to the formation of secondary organic aerosol (SOA) (e.g. Pandis et al., 1991; Kavouras et al., 1999). The ozonolysis reactions of olefins result in complex menageries of products, of which the acids are ubiquitous. Although the gas phase acid concentrations are small, they are thought to be key species in SOA formation as a result of their low volatility (e.g., Ma et al., 2009). Despite this, the factors that control acid formation are not well understood, especially with regards to humidity and temperature. Acid yields will be measured using the newly commissioned EXTreme RAnge (EXTRA) chamber (Leather et al., 2009). EXTRA is a 125 L stainless steel chamber, which can be temperature controlled using a commercial chest freezer unit (for T ≤ -20 °C) or a purpose built oven for T > 25 °C. The EXTRA chamber can be operated at pressures from 10-3800 Torr and at temperatures from 180-473 K. The stainless steel chamber walls have been coated with PFA to minimize wall loss of radicals. Fans, located at both ends of the cylinder, promote rapid mixing of reactants. Six sample ports are located at either end of the chamber for connection to ADS-GC-ECD, CIMS and commercial sensors such as a Thermo Electron Corporation 49i Ozone Analyzer, an Edinburgh Instruments Gascard CO2 sensor and a Trace Analytical inc. RGA3 CO analyzer. Experiments will be performed as a function of atmospherically relevant temperatures (T= 180-300 K). The field CIMS has sub ppt(v) L.O.D.s with a sub 1 Hz time response so will enable products to be quantified at very low concentrations in real time. Acid products will be detected

  20. Analysis of sterols and fatty acids in natural and cultured Cordyceps by one-step derivatization followed with gas chromatography-mass spectrometry.

    Science.gov (United States)

    Yang, F Q; Feng, K; Zhao, J; Li, S P

    2009-07-12

    Ten free fatty acids namely lauric acid, myristic acid, pentadecanoic acid, palmitoleic acid, palmitic acid, linoleic acid, oleic acid, stearic acid, docosanoic acid and lignoceric acid and four free sterols including ergosterol, cholesterol, campesterol and beta-sitosterol in natural (wild) Cordyceps sinensis, Cordyceps liangshanensis and Cordyceps gunnii, as well as cultured C. sinensis and Cordyceps militaris were first determined using pressurized liquid extraction (PLE), trimethylsilyl (TMS) derivatization and GC-MS analysis. The conditions such as the amount of reagent, temperature and time for TMS derivatization of analytes were optimized. Under the optimum conditions, all calibration curves showed good linearity within the tested ranges. The intra- and inter-day variations for 14 investigated compounds were less than 3.4% and 5.2%, respectively. The results showed that palmitic acid, linoleic acid, oleic acid, stearic acid and ergosterol are main components in natural and cultured Cordyceps which could be discriminated by hierarchical clustering analysis based on the contents of 14 investigated compounds or the 4 fatty acids, where the contents of palmitic acid and oleic acid in natural Cordyceps are significantly higher than those in the cultured ones.

  1. Periurbanisation and natural hazards

    Directory of Open Access Journals (Sweden)

    Delphine Loison

    2009-03-01

    Full Text Available In mountainous areas in recent decades urbanisation has expanded to areas where low ground adjoins mountainsides that are unstable in a number of respects. Periurbanisation in mountain basins with unstable sides poses specific problems that local players have to address. The Lavanchon basin (southeast of Grenoble, which is subject to very rapid urban growth combined with particularly dynamic mountainsides, is representative of the way activity is being brought into closer contact with potential hazards. A diachronic study of changes in land use between 1956 and 2001 shows how valley infrastructures at the bottom of mountainsides have become increasingly dense. In this context, a survey was carried out among a number of residents in the Lavanchon basin in an attempt to evaluate the degree of awareness that the population has of the natural hazards to which it is exposed. The results show that slightly more than half of the population surveyed was aware of the problem of natural hazards being present in the area, with most inhabitants being more concerned about industrial and pollution hazards. New residents were unaware of or were unwilling to accept the reality of hazards. The low incidence of significant natural events, the effectiveness of the protective structures built, the absence of information provided by the public authorities and the division of the basin between several management bodies appear to have engendered a feeling of safety from natural phenomena. The geographical distribution of appreciation of the hazard clearly shows a distinction between those inhabitants living on the low ground and those at the bottom of the mountainsides, and this corresponds fairly closely with the historical and current location of the main potentially hazardous events that have occurred.Dans les territoires de montagne, les dernières décennies ont vu l’expansion de l’urbanisation vers les zones de contact entre la plaine et les versants, lieux

  2. Hazard maps of Colima volcano, Mexico

    Science.gov (United States)

    Suarez-Plascencia, C.; Nunez-Cornu, F. J.; Escudero Ayala, C. R.

    2011-12-01

    Colima volcano, also known as Volcan de Fuego (19° 30.696 N, 103° 37.026 W), is located on the border between the states of Jalisco and Colima and is the most active volcano in Mexico. Began its current eruptive process in February 1991, in February 10, 1999 the biggest explosion since 1913 occurred at the summit dome. The activity during the 2001-2005 period was the most intense, but did not exceed VEI 3. The activity resulted in the formation of domes and their destruction after explosive events. The explosions originated eruptive columns, reaching attitudes between 4,500 and 9,000 m.a.s.l., further pyroclastic flows reaching distances up to 3.5 km from the crater. During the explosive events ash emissions were generated in all directions reaching distances up to 100 km, slightly affected nearby villages as Tuxpan, Tonila, Zapotlán, Cuauhtemoc, Comala, Zapotitlan de Vadillo and Toliman. During the 2005 this volcano has had an intense effusive-explosive activity, similar to the one that took place during the period of 1890 through 1900. Intense pre-plinian eruption in January 20, 1913, generated little economic losses in the lower parts of the volcano due to low population density and low socio-economic activities at the time. Shows the updating of the volcanic hazard maps published in 2001, where we identify whit SPOT satellite imagery and Google Earth, change in the land use on the slope of volcano, the expansion of the agricultural frontier on the east and southeast sides of the Colima volcano, the population inhabiting the area is approximately 517,000 people, and growing at an annual rate of 4.77%, also the region that has shown an increased in the vulnerability for the development of economic activities, supported by the construction of highways, natural gas pipelines and electrical infrastructure that connect to the Port of Manzanillo to Guadalajara city. The update the hazard maps are: a) Exclusion areas and moderate hazard for explosive events

  3. Overconfidence and Moral Hazard

    DEFF Research Database (Denmark)

    de la Rosa, Leonidas Enrique

    In this paper, I study the effects of overconfidence on incentive contracts in a moral-hazard framework in which principal and agent knowingly hold asymmetric beliefs regarding the probability of success of their enterprise. Agent overconfidence can have conflicting effects on the equilibrium......-powered incentives are sufficient to induce any given effort level. If the agent is overall moderately overconfident, the latter effect dominates; because the agent bears less risk in this case, he actually benefits from his overconfidence. If the agent is significantly overconfident, the former effect dominates......; the agent is then exposed to an excessive amount of risk, which is harmful to him. An increase in overconfidence--either about the base probability of success or the extent to which effort affects it--makes it more likely that high levels of effort are implemented in equilibrium....

  4. Sports: The Infectious Hazards.

    Science.gov (United States)

    Minooee, Arezou; Wang, Jeff; Gupta, Geeta K

    2015-10-01

    Although the medical complications of sports are usually traumatic in nature, infectious hazards also arise. While blood-borne pathogens such as HIV, hepatitis B, and hepatitis C, cause significant illness, the risk of acquiring these agents during sporting activities is minimal. Skin infections are more commonplace, arising from a variety of microbial agents including bacterial, fungal, and viral pathogens. Sports involving water contact can lead to enteric infections, eye infections, or disseminated infections such as leptospirosis. Mumps, measles, and influenza are vaccine-preventable diseases that have been transmitted during sporting events, both in players and in spectators. Prevention is the key to many of these infections. Players should be vaccinated and should not participate in sports if their infection can be spread by contact, airborne, or droplet transmission.

  5. Identification of Potential Hazard using Hazard Identification and Risk Assessment

    Science.gov (United States)

    Sari, R. M.; Syahputri, K.; Rizkya, I.; Siregar, I.

    2017-03-01

    This research was conducted in the paper production’s company. These Paper products will be used as a cigarette paper. Along in the production’s process, Company provides the machines and equipment that operated by workers. During the operations, all workers may potentially injured. It known as a potential hazard. Hazard identification and risk assessment is one part of a safety and health program in the stage of risk management. This is very important as part of efforts to prevent occupational injuries and diseases resulting from work. This research is experiencing a problem that is not the identification of potential hazards and risks that would be faced by workers during the running production process. The purpose of this study was to identify the potential hazards by using hazard identification and risk assessment methods. Risk assessment is done using severity criteria and the probability of an accident. According to the research there are 23 potential hazard that occurs with varying severity and probability. Then made the determination Risk Assessment Code (RAC) for each potential hazard, and gained 3 extreme risks, 10 high risks, 6 medium risks and 3 low risks. We have successfully identified potential hazard using RAC.

  6. 活性炭脱硫富集烟气制酸系统技术改造实践%Technological revamping of sulphuric acid plant based on off-gas enriched by activated carbon desulphurization

    Institute of Scientific and Technical Information of China (English)

    李强

    2012-01-01

    The process and problems of the sulphuric acid plant based on a new 450 m2 sintering machine off-gas which is enriched by activated carbon desulphurization are introduced. Some improvements were made in accordance with lower gas temperature at spray tower inlet, insufficient bubble column height, high dust content at the inlet of drying tower, serious acid accumulation in acid distributor groove and darken product acid color. After retrofitting, the system operated well and the product acid became clear and transparent.%介绍了新450m^2烧结机烟气活性炭脱硫富集烟气制酸系统流程和存在问题。针对喷淋塔进口烟气温度偏低、泡沫柱高度不足、干燥塔进口尘含量超高、分酸槽内酸泥堆积严重、成品酸色度差等问题采取有效改造措施。改造后系统运行正常,产品酸清澈透明。

  7. Design features of a sulphuric acid plant based on lead and zinc sintering machine off-gas%硫酸用新型耐蚀合金的研究与开发

    Institute of Scientific and Technical Information of China (English)

    刘焕安

    2001-01-01

    Design features of a 150kt/a sulphuric acid plant based on lead and zinc sintering machine off-gases are described. The plant adopted a single absorption technology including closed dilute-acid-scrubbing gas cleaning and ammonia-acid off-gas treatment. The dilute acid settling system,cooling water circulation system, installation of electrostatic precipitator, high-temperature absorption technology and acid distributor of drying and absorption section, and preheater, hot bypass and insulation of conversion section are emphasized in detail.%论述硫酸对金属腐蚀的特殊性和合金设计的基本原理。介绍高温浓硫酸用高硅不锈钢HD-1、合金球墨铸铁HD-3以及稀硫酸用高钼含氮奥氏体不锈钢HD-7、HD-11的研究开发和应用范围。

  8. Estimation of the uncertainty associated with the results based on the validation of chromatographic analysis procedures: application to the determination of chlorides by high performance liquid chromatography and of fatty acids by high resolution gas chromatography.

    Science.gov (United States)

    Quintela, M; Báguena, J; Gotor, G; Blanco, M J; Broto, F

    2012-02-03

    This article presents a model to calculate the uncertainty associated with an analytical result based on the validation of the analysis procedure. This calculation model is proposed as an alternative to commonly used bottom-up and top-down methods. This proposal is very advantageous as the validation of the procedures and the estimation of the uncertainty of the measurement are part of the technical requirements needed in order to obtain the ISO 17025:2005 accreditation. This model has been applied to the determination of chloride by liquid chromatography in lixiviates and in the determination of palmitic acid and stearic acid by gas chromatography in magnesium stearate samples.

  9. Simultaneous determination of total fatty acid esters of chloropropanols in edible oils by gas chromatography-mass spectrometry with solid-supported liquid-liquid extraction.

    Science.gov (United States)

    Liu, Qing; Han, Feng; Xie, Ke; Miao, Hong; Wu, Yongning

    2013-11-01

    This study aimed to establish a novel robust method for the simultaneous determination of total fatty acid esters of 4 chloropropanols including fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD esters), 2-monochloropropane-1,3-diol (2-MCPD esters), 1,3-dichloropropan-2-ol (1,3-DCP esters) and 2,3-dichloropropan-1-ol (2,3-DCP esters) in edible oils. In this method, sodium methylate in methanol was used as the reagent for the ester cleavage reaction of chloropropanols esters. The reaction products were extracted by a sodium sulfate solution, and then purified by solid-supported liquid-liquid extraction (SLE) using diatomaceous earth (Hydromatrix™) as the sorbent. Finally, the extracts were derivatized with heptafluorobutyrylim idazole (HFBI) and analyzed by gas chromatography-mass spectrometry (GC-MS). Quantification was achieved using deuterated chloropropanols as their respective internal standards, including 3-MCPD-d5, 2-MCPD-d5, 1,3-DCP-d5 and 2,3-DCP-d5. A good linear relationship between peak area and concentrations was obtained within the range of 0.025-2.000mgL(-1) with a correlation coefficients not less than 0.999 for all the chloropropanols esters. The limits of detection (LODs) of esters of 3-MCPD, 2-MCPD, 1,3-DCP and 2,3-DCP (calculated as corresponding chloropropanols) were 30, 30, 100 and 30μgkg(-1), respectively. The average recoveries of the 3-MCPD esters and the 4 chloropropanols spiked at 0.1, 0.5 and 2mgkg(-1) into blank oil matrix were typically in a range from 70.7% to 113.3%. The robust method validation data including calibration, LOD/LOQ, accuracy and repeatability and proficiency test results (Z-score: -0.5) of the official Food Analysis Performance Assessment Scheme (FAPAS) indicated that the present quantitative method could be successfully applied to the determination of total chloropropanols esters in various edible oils.

  10. Can Blood Gas and Acid-Base Parameters at Maximal 200 Meters Front Crawl Swimming be Different Between Former Competitive and Recreational Swimmers?

    Science.gov (United States)

    Kapus, Jernej; Usaj, Anton; Strumbelj, Boro; Kapus, Venceslav

    2008-01-01

    The aim of the present study was to ascertain whether maximal 200 m front crawl swimming strategies and breathing patterns influenced blood gas and acid-base parameters in a manner which gives advantage to former competitive swimmers in comparison with their recreational colleagues. Twelve former competitive male swimmers (the CS group) and nine recreational male swimmers (the RS group) performed a maximal 200 m front crawl swimming with self- selected breathing pattern. Stroke rate (SR) and breathing frequency (BF) were measured during the swimming test. Measures also included blood lactate concentration ([LA]) and parameters of blood acid-base status before and during the first minute after the swimming test. The CS group swam faster then the RS group. Both groups have similar and steady SR throughout the swimming test. This was not matched by similar BF in the CS group but matched it very well in the RS group (r = 0.89). At the beginning of swimming test the CS group had low BF, but they increased it throughout the swimming test. The BF at the RS group remained constant with only mirror variations throughout the swimming test. Such difference in velocity and breathing resulted in maintaining of blood Po2 from hypoxia and Pco2 from hypercapnia. This was similar in both groups. [LA] increased faster in the CS group than in the RS group. On the contrary, the rate of pH decrease remained similar in both groups. The former competitive swimmers showed three possible advantages in comparison to recreational swimmers during maximal 200 m front crawl swimming: a more dynamic and precise regulation of breathing, more powerful bicarbonate buffering system and better synchronization between breathing needs and breathing response during swimming. Key pointsTraining programs for competitive swimmers should promote adaptations to maximal efforts.Those adaptations should include high and maximal intensity swims with controlled breathing frequency (taking breath every fourth

  11. Determination of Sulfuric Acid Mist in the Waste Gas of Stalionary Pollution Sources by Ion Chromatography%离子色谱法对固定污染源废气硫酸雾的测定

    Institute of Scientific and Technical Information of China (English)

    刘畅

    2011-01-01

    对用离子色谱法测定固定污染源废气硫酸雾的原理、所用药品、仪器条件、样品前处理以及整个操作过程进行详细介绍,并阐述计算方法,以为测定废气中硫酸雾含量提供技术参考。%Ion chromatography determination of sulfuric acid mist in the waste gas of stalionary pollution sources principle,used in medicines,instruments,sample preparation,as well as the entire procedure was described in detail and presented the results of calculation method,it could provide technical references for content determination of sulfuric acid mist in exhaust gas.

  12. 75 FR 72877 - Pipeline Safety: Updates to Pipeline and Liquefied Natural Gas Reporting Requirements

    Science.gov (United States)

    2010-11-26

    ... Safety: Updates to Pipeline and Liquefied Natural Gas Reporting Requirements; Final Rule #0;#0;Federal... to Pipeline and Liquefied Natural Gas Reporting Requirements AGENCY: Pipeline and Hazardous Materials... collections from operators of natural gas pipelines, hazardous liquid pipelines, and liquefied natural......

  13. CHRIS: Hazardous Chemical Data

    Science.gov (United States)

    1978-10-01

    STCCK:STRAIGHT RUN RESICUE CARTHAMuS TINCTCRIUS OIL OILS1. EDIBLE: SAFFLOWER CARWINATE 125t1 DIPHEI4YLPETHANEOIISOCYANATE (NC!) CATECHIN -CATE00OL...CALCIUM PHOSPHATETCE ccoTOI TOLUENE 294-DIISCCYANATE 4TOIl TEA TRIETPYLALUMINL TEAR GAS aCLOROACETOPHENONE TEFLON "ONOMER TETRAFLUCROETHYLEEv U...TETRADECYLEENZENE lT - ETRADECN TDC 1-RIDTIEE TETRACHLOROETHYLENE TDI TOLUENE 2 ,4-DIISOCYANATE IG TTATYEECYO TDN IRIDECANOL I TETRADECANOL TEA

  14. Effect of acid-catalyzed formation rates of benzimidazole-linked polymers on porosity and selective CO2 capture from gas mixtures.

    Science.gov (United States)

    Altarawneh, Suha; İslamoğlu, Timur; Sekizkardes, Ali Kemal; El-Kaderi, Hani M

    2015-04-01

    Benzimidazole-linked polymers (BILPs) are emerging candidates for gas storage and separation applications; however, their current synthetic methods offer limited control over textural properties which are vital for their multifaceted use. In this study, we investigate the impact of acid-catalyzed formation rates of the imidazole units on the porosity levels of BILPs and subsequent effects on CO2 and CH4 binding affinities and selective uptake of CO2 over CH4 and N2. Treatment of 3,3'-Diaminobenzidine tetrahydrochloride hydrate with 1,2,4,5-tetrakis(4-formylphenyl)benzene and 1,3,5-(4-formylphenyl)-benzene in anhydrous DMF afforded porous BILP-15 (448 m(2) g(-1)) and BILP-16 (435 m(2) g(-1)), respectively. Alternatively, the same polymers were prepared from the neutral 3,3'-Diaminobenzidine and catalytic amounts of aqueous HCl. The resulting polymers denoted BILP-15(AC) and BILP-16(AC) exhibited optimal surface areas; 862 m(2) g(-1) and 643 m(2) g(-1), respectively, only when 2 equiv of HCl (0.22 M) was used. In contrast, the CO2 binding affinity (Qst) dropped from 33.0 to 28.9 kJ mol(-1) for BILP-15 and from 32.0 to 31.6 kJ mol(-1) for BILP-16. According to initial slope calculations at 273 K/298 K, a notable change in CO2/N2 selectivity was observed for BILP-15(AC) (61/50) compared to BILP-15 (83/63). Similarly, ideal adsorbed solution theory (IAST) calculations also show the higher specific surface area of BILP-15(AC) and BILP-16(AC) compromises their CO2/N2 selectivity.

  15. Graphitic carbon nitrides modified hollow fiber solid phase microextraction for extraction and determination of uric acid in urine and serum coupled with gas chromatography-mass spectrometry.

    Science.gov (United States)

    Sun, Ying-pei; Chen, Juan; Qi, Huan-yang; Shi, Yan-ping

    2015-11-01

    An elevated uric acid (UA) in urine or serum can affect renal function and blood pressure, which is an indicator of gout, cardiovascular and renal diseases, hypertension, etc. In this work, a new type of mixed matrix membrane (MMM), based on graphitic carbon nitrides (g-CNs) and hollow fiber (HF), was prepared and combined with solid phase microextraction (SPME) mode to determine UA in urine and serum followed by gas chromatography-mass spectrometry (GC/MS). The porous g-CNs were dispersed in ammonia, and then the exfoliated g-CNs nanosheets were held in the pores of HF by capillary forces and sonification. The prepared g-CNs modified HF (g-CNs-HF) was immersed in biofluid directly to extract UA with SPME mode and the solvent-free mode is convenient for further derivatization and analysis. To achieve the highest extraction efficiency (EF), main extraction and derivatization parameters, such as g-CNs-HF immobilizing time, sonification power and time of extraction, derivatization and desorption time, were optimized. Under the optimum extraction conditions, a favorable linearity of UA was obtained in the range 0.1-200μgmL(-1) with correlation coefficients higher than 0.9990, and the average recoveries at three spiked levels of UA in urine and serum ranged from 80.7% to 121.6%, from 84.7% to 101.1%, respectively. The obtained results demonstrated the developed g-CNs-HF-SPME is a simple, rapid, cost-effective, solvent-free method for the analysis of UA in biofluid.

  16. State estimation of an acid gas removal (AGR) plant as part of an integrated gasification combined cycle (IGCC) plant with CO2 capture

    Energy Technology Data Exchange (ETDEWEB)

    Paul, P.; Bhattacharyya, D.; Turton, R.; Zitney, S.

    2012-01-01

    An accurate estimation of process state variables not only can increase the effectiveness and reliability of process measurement technology, but can also enhance plant efficiency, improve control system performance, and increase plant availability. Future integrated gasification combined cycle (IGCC) power plants with CO2 capture will have to satisfy stricter operational and environmental constraints. To operate the IGCC plant without violating stringent environmental emission standards requires accurate estimation of the relevant process state variables, outputs, and disturbances. Unfortunately, a number of these process variables cannot be measured at all, while some of them can be measured, but with low precision, low reliability, or low signal-to-noise ratio. As a result, accurate estimation of the process variables is of great importance to avoid the inherent difficulties associated with the inaccuracy of the data. Motivated by this, the current paper focuses on the state estimation of an acid gas removal (AGR) process as part of an IGCC plant with CO2 capture. This process has extensive heat and mass integration and therefore is very suitable for testing the efficiency of the designed estimators in the presence of complex interactions between process variables. The traditional Kalman filter (KF) (Kalman, 1960) algorithm has been used as a state estimator which resembles that of a predictor-corrector algorithm for solving numerical problems. In traditional KF implementation, good guesses for the process noise covariance matrix (Q) and the measurement noise covariance matrix (R) are required to obtain satisfactory filter performance. However, in the real world, these matrices are unknown and it is difficult to generate good guesses for them. In this paper, use of an adaptive KF will be presented that adapts Q and R at every time step of the algorithm. Results show that very accurate estimations of the desired process states, outputs or disturbances can be

  17. 酵母产气特性及其对馒头面团酸度的影响%Effects of yeast characteristic of gas production on the acidity of steamed bread dough

    Institute of Scientific and Technical Information of China (English)

    宋金丽; 郑心羽; 张佩

    2015-01-01

    In aim to identify the gas characteristics produced by different species of yeasts and their influ-ence on fermented dough acidity,the curves of gas production,under the condition of 28,32,35,38 and 40 ℃,were determined respectively.The acidity and pH value of dough during fermentation were deter-mined as well.Results showed that the optimum temperature for gas production was 38 ℃.The gas prop-erties of dough,fermented by different yeasts,were obviously different.The acidity and pH value of dough was relevant to both adding amount of yeast and sugar resistant characteristics of yeast.The acidity was increasing during fermentation process,thus the pH value declined.%为确定不同品种酵母产气特性及其对发酵面团酸度的影响,将发酵面团于28、32、35、38、40℃五个温度条件下测定面团发酵产气曲线图,对发酵过程中面团的酸度和 pH 进行测定。结果表明酵母最佳产气温度为38℃,添加不同品种酵母面团的产气性能有明显差异,面团发酵酸度和面团 pH 与酵母的添加量和酵母耐糖特性均有关系,发酵过程中面团酸度呈现上升趋势,面团 pH逐渐下降。

  18. 高含硫气田开发酸污对天然气净化厂输电线路安全影响研究及防护措施优选%Optimization of protective measures and safety impact study of high sulfur gas field acid pollution on the electric transmission line of natural gas purification plant

    Institute of Scientific and Technical Information of China (English)

    王和琴; 陈惟国; 苗辉; 周培利

    2013-01-01

    基于高含硫气田开发过程中的天然气净化厂尾气排放特性及在大气中浓度分布的预测,以普光气田为例,就酸性气体对220 kV 线路绝缘性能分析,分别测试了模拟酸雾环境中污秽绝缘子以及空气的绝缘性能。结果表明,在盐雾的作用下,绝缘子的闪络电压下降了约20%,雾的pH值为3时,空气的绝缘强度下降了约15.1%,pH值等于3的酸雾与II级空气污染相结合,空气的绝缘强度大约下降了23.2%。在pH值等于3的酸雨酸雾环境下,线路的耐雷水平下降了约20%。结合实验室分析结果和普光气田的实际情况,分析了酸性气田输电线路的防护措施。%Based on the gas emission characteristics of natural gas purification plant and con-centration distribution prediction in atmosphere during the development process of high sour gas filed ,insulation performance analysis of acid gases on the 220 kV line was conducted ,taking Pu-guang gas field as example .Insulating property of polluted insulator and the air under simulated acid mist environment were measured respectively .The results showed that flashover voltage of insulator dropped about 20% under the action of salt mist .Insulating strength of the air dropped about 15 .1% when the pH value of mist was 3 .After the combination of acid mist (pH=3) and class II air pollution ,insulating strength of the air dropped about 23 .2% .Lightning withstand level of electric transmission line decreased 20% approximately under acid rain and acid mist envi-ronment with pH value of 3 .Combined the laboratory analysis results and practical situation in Puguang gas field ,the protective measures of electric transmission line in acid gas field were ana-lyzed .

  19. Hazard Map for Autonomous Navigation

    DEFF Research Database (Denmark)

    Riis, Troels

    This dissertation describes the work performed in the area of using image analysis in the process of landing a spacecraft autonomously and safely on the surface of the Moon. This is suggested to be done using a Hazard Map. The correspondence problem between several Hazard Maps are investigated fu...

  20. Global Polynomial Kernel Hazard Estimation

    DEFF Research Database (Denmark)

    Hiabu, Munir; Miranda, Maria Dolores Martínez; Nielsen, Jens Perch

    2015-01-01

    This paper introduces a new bias reducing method for kernel hazard estimation. The method is called global polynomial adjustment (GPA). It is a global correction which is applicable to any kernel hazard estimator. The estimator works well from a theoretical point of view as it asymptotically redu...