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Sample records for flammable gas single

  1. FLAMMABLE GAS DIFFUSION THROUGH SINGLE SHELL TANK (SST) DOMES

    Energy Technology Data Exchange (ETDEWEB)

    MEACHAM, J.E.

    2003-11-10

    This report quantified potential hydrogen diffusion through Hanford Site Single-Shell tank (SST) domes if the SSTs were hypothetically sealed airtight. Results showed that diffusion would keep headspace flammable gas concentrations below the lower flammability limit in the 241-AX and 241-SX SST. The purpose of this document is to quantify the amount of hydrogen that could diffuse through the domes of the SSTs if they were hypothetically sealed airtight. Diffusion is assumed to be the only mechanism available to reduce flammable gas concentrations. The scope of this report is limited to the 149 SSTs.

  2. Methodology for flammable gas evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, J.D., Westinghouse Hanford

    1996-06-12

    There are 177 radioactive waste storage tanks at the Hanford Site. The waste generates flammable gases. The waste releases gas continuously, but in some tanks the waste has shown a tendency to trap these flammable gases. When enough gas is trapped in a tank`s waste matrix, it may be released in a way that renders part or all of the tank atmosphere flammable for a period of time. Tanks must be evaluated against previously defined criteria to determine whether they can present a flammable gas hazard. This document presents the methodology for evaluating tanks in two areas of concern in the tank headspace:steady-state flammable-gas concentration resulting from continuous release, and concentration resulting from an episodic gas release.

  3. Flammable gas project topical report

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, G.D.

    1997-01-29

    The flammable gas safety issue was recognized in 1990 with the declaration of an unreviewed safety question (USQ) by the U. S. Department of Energy as a result of the behavior of the Hanford Site high-level waste tank 241-SY-101. This tank exhibited episodic releases of flammable gas that on a couple of occasions exceeded the lower flammability limit of hydrogen in air. Over the past six years there has been a considerable amount of knowledge gained about the chemical and physical processes that govern the behavior of tank 241-SY-1 01 and other tanks associated with the flammable gas safety issue. This report was prepared to provide an overview of that knowledge and to provide a description of the key information still needed to resolve the issue. Items covered by this report include summaries of the understanding of gas generation, retention and release mechanisms, the composition and flammability behavior of the gas mixture, the amounts of stored gas, and estimated gas release fractions for spontaneous releases. `Me report also discusses methods being developed for evaluating the 177 tanks at the Hanford Site and the problems associated with these methods. Means for measuring the gases emitted from the waste are described along with laboratory experiments designed to gain more information regarding rates of generation, species of gases emitted and modes of gas storage and release. Finally, the process for closing the USQ is outlined as are the information requirements to understand and resolve the flammable gas issue.

  4. 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).

  5. The Chemistry of Flammable Gas Generation

    Energy Technology Data Exchange (ETDEWEB)

    ZACH, J.J.

    2000-10-30

    The document collects information from field instrumentation, laboratory tests, and analytical models to provide a single source of information on the chemistry of flammable gas generation at the Hanford Site. It considers the 3 mechanisms of formation: radiolysis, chemical reactions, and thermal generation. An assessment of the current models for gas generation is then performed. The results are that the various phenomena are reasonably understood and modeled compared to field data.

  6. A safety assessment of rotary mode core sampling in flammable gas single shell tanks: Hanford Site, Richland, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, R.E.

    1996-04-15

    This safety assessment (SA) addresses each of the required elements associated with the installation, operation, and removal of a rotary-mode core sampling (RMCS) device in flammable-gas single-shell tanks (SSTs). The RMCS operations are needed in order to retrieve waste samples from SSTs with hard layers of waste for which push-mode sampling is not adequate for sampling. In this SA, potential hazards associated with the proposed action were identified and evaluated systematically. Several potential accident cases that could result in radiological or toxicological gas releases were identified and analyzed and their consequences assessed. Administrative controls, procedures and design changes required to eliminate or reduce the potential of hazards were identified. The accidents were analyzed under nine categories, four of which were burn scenarios. In SSTS, burn accidents result in unacceptable consequences because of a potential dome collapse. The accidents in which an aboveground burn propagates into the dome space were shown to be in the ``beyond extremely unlikely`` frequency category. Given the unknown nature of the gas-release behavior in the SSTS, a number of design changes and administrative controls were implemented to achieve these low frequencies. Likewise, drill string fires and dome space fires were shown to be very low frequency accidents by taking credit for the design changes, controls, and available experimental and analytical data. However, a number of Bureau of Mines (BOM) tests must be completed before some of the burn accidents can be dismissed with high confidence. Under the category of waste fires, the possibility of igniting the entrapped gases and the waste itself were analyzed. Experiments are being conducted at the BOM to demonstrate that the drill bit is not capable of igniting the trapped gas in the waste. Laboratory testing and thermal analysis demonstrated that, under normal operating conditions, the drill bit will not create high

  7. Offsite Radiological Consequence Analysis for the Bounding Flammable Gas Accident

    CERN Document Server

    Carro, C A

    2003-01-01

    This document quantifies the offsite radiological consequences of the bounding flammable gas accident for comparison with the 25 rem Evaluation Guideline established in DOE-STD-3009, Appendix A. The bounding flammable gas accident is a detonation in a single-shell tank The calculation applies reasonably conservation input parameters in accordance with DOE-STD-3009, Appendix A, guidance. Revision 1 incorporates comments received from Office of River Protection.

  8. Flammable gas interlock spoolpiece flow response test plan and procedure

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, T.C., Fluor Daniel Hanford

    1997-02-13

    The purpose of this test plan and procedure is to test the Whittaker electrochemical cell and the Sierra Monitor Corp. flammable gas monitors in a simulated field flow configuration. The sensors are used on the Rotary Mode Core Sampling (RMCS) Flammable Gas Interlock (FGI), to detect flammable gases, including hydrogen and teminate the core sampling activity at a predetermined concentration level.

  9. Flammable gas interlock spoolpiece flow response test report

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, T.C., Fluor Daniel Hanford

    1997-03-24

    The purpose of this test report is to document the testing performed under the guidance of HNF-SD-WM-TC-073, {ital Flammable Gas Interlock Spoolpiece Flow Response Test Plan and Procedure}. This testing was performed for Lockheed Martin Hanford Characterization Projects Operations (CPO) in support of Rotary Mode Core Sampling jointly by SGN Eurisys Services Corporation and Numatec Hanford Company. The testing was conducted in the 305 building Engineering Testing Laboratory (ETL). NHC provides the engineering and technical support for the 305 ETL. The key personnel identified for the performance of this task are as follows: Test responsible engineering manager, C. E. Hanson; Flammable Gas Interlock Design Authority, G. P. Janicek; 305 ETL responsible manager, N. J. Schliebe; Cognizant RMCS exhauster engineer, E. J. Waldo/J. D. Robinson; Cognizant 305 ETL engineer, K. S. Witwer; Test director, T. C. Schneider. Other support personnel were supplied, as necessary, from 305/306 ETL. The testing, on the flammable Gas Interlock (FGI) system spoolpiece required to support Rotary Mode Core Sampling (RMCS) of single shell flammable gas watch list tanks, took place between 2-13-97 and 2-25-97.

  10. Flammable Gas Detection for the D-Zero Gas System

    Energy Technology Data Exchange (ETDEWEB)

    Spires, L.D.; Foglesong, J.; /Fermilab

    1991-02-11

    The use of flammable gas and high voltage in detector systems is common in many experiments at Fermilab. To mitigate the hazards associated with these systems, Fermilab Engineering Standard SD-45B (Ref. 1) was adopted. Since this note is meant to be a guide and not a mandatory standard, each experiment is reviewed for compliance with SD-45B by the flammable gas safety subcommittee. Currently, there are only two types of flammable gas in use, ethane (Appendix A) and methane (Appendix B). The worst flammable-gas case is C2H6 (ethane), which has an estimated flow rate that is 73% of the CH4 (methane) flow but a heat of combustion (in kcal/g-mole) that is 173% of that of methane. In the worst case, if ethane were to spew through its restricting orifice into its gas line at 0 psig and then through a catastrophic leak into Room 215 (TRD) or Room 511 (CDC/FDCNTX), the time that would be required to build up a greater than Class 1 inventory (0.4kg H2 equivalent) would be 5.2 hours (Ref. 2). Therefore a worst-case flammable gas leak would have to go undetected for over 5 hours in order to transform a either mixing room to an environment with a Risk Class greater than Class 1. The mixing systems, gas lines, and detectors themselves will be thoroughly leak checked prior to active service. All vessels that are part of the mixing systems will be protected from overpressure by safety valves vented outside the building. Both the input and output of all detector volumes are protected from overpressure in the same way. The volume immediately outside the central tracking detectors is continuously purged by nitrogen from boiloff from the main nitrogen dewar at the site. However, if flammable gas were to build up in the mixing rooms or particular detector areas, no matter how unlikely, flammable gas detectors that are part of the interlock chain of each gas mixing system will shut down the appropriate system. This includes shutting off the output of flammable gas manifolds within the

  11. Retained Gas Sampling Results for the Flammable Gas Program

    Energy Technology Data Exchange (ETDEWEB)

    J.M. Bates; L.A. Mahoney; M.E. Dahl; Z.I. Antoniak

    1999-11-18

    The key phenomena of the Flammable Gas Safety Issue are generation of the gas mixture, the modes of gas retention, and the mechanisms causing release of the gas. An understanding of the mechanisms of these processes is required for final resolution of the safety issue. Central to understanding is gathering information from such sources as historical records, tank sampling data, tank process data (temperatures, ventilation rates, etc.), and laboratory evaluations conducted on tank waste samples.

  12. Flammability of Gas-Filled Polymers

    Directory of Open Access Journals (Sweden)

    Ushkov Valentin Anatol'evich

    2017-09-01

    Full Text Available The regularities of flame propagation on the horizontal surface of gas-filled polymers are considered depending on the concentration of oxygen in the oxidizer flow. The values of the coefficients in the expression describing relationship between the rate of flame propagation on the surface of foams and oxygen concentration are obtained. It was shown that with the mass content of reactive organophosphorus compounds reaching 4.0...5.9%, non-smoldering resole foam plastics with high performance characteristics are obtained. It was found that in order to obtain moderately combustible polyurethane foams based on oxyethylated phosphorus-containing polyols, the phosphorus concentration should not exceed 3 % of mass. To obtain flame-retardant urea-formaldehyde foam cellular plastics, the concentration of phosphorus should not exceed 0.3 % of mass. Physical-mechanical properties and flammability indices of developed gas-filled polymers based on reactive oligomers are presented.

  13. STEADY-STATE FLAMMABLE GAS RELEASE RATE CALCULATION AND LOWER FLAMMABILITY LEVEL EVALUATION FOR HANFORD TANK WASTE

    Energy Technology Data Exchange (ETDEWEB)

    HU TA

    2007-10-26

    Assess the steady-state flammability level at normal and off-normal ventilation conditions. The methodology of flammability analysis for Hanford tank waste is developed. The hydrogen generation rate model was applied to calculate the gas generation rate for 177 tanks. Flammability concentrations and the time to reach 25% and 100% of the lower flammability limit, and the minimum ventilation rate to keep from 100 of the LFL are calculated for 177 tanks at various scenarios.

  14. 46 CFR 30.10-39 - Liquefied flammable gas-TB/ALL.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Liquefied flammable gas-TB/ALL. 30.10-39 Section 30.10-39 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Definitions § 30.10-39 Liquefied flammable gas—TB/ALL. The term liquefied flammable gas means any flammable gas...

  15. STEADY STATE FLAMMABLE GAS RELEASE RATE CALCULATION & LOWER FLAMMABILITY LEVEL EVALUATION FOR HANFORD TANK WASTE [SEC 1 & 2

    Energy Technology Data Exchange (ETDEWEB)

    HU, T.A.

    2003-09-30

    Flammable gases such as hydrogen, ammonia, and methane are observed in the tank dome space of the Hanford Site high-level waste tanks. This report assesses the steady-state flammability level under normal and off-normal ventilation conditions in the tank dome space for 177 double-shell tanks and single-shell tanks at the Hanford Site. The steady-state flammability level was estimated from the gas concentration of the mixture in the dome space using estimated gas release rates, Le Chatelier's rule and lower flammability limits of fuels in an air mixture. A time-dependent equation of gas concentration, which is a function of the gas release and ventilation rates in the dome space, has been developed for both soluble and insoluble gases. With this dynamic model, the time required to reach the specified flammability level at a given ventilation condition can be calculated. In the evaluation, hydrogen generation rates can be calculated for a given tank waste composition and its physical condition (e.g., waste density, waste volume, temperature, etc.) using the empirical rate equation model provided in Empirical Rate Equation Model and Rate Calculations of Hydrogen Generation for Hanford Tank Waste, HNF-3851. The release rate of other insoluble gases and the mass transport properties of the soluble gas can be derived from the observed steady-state gas concentration under normal ventilation conditions. The off-normal ventilation rate is assumed to be natural barometric breathing only. A large body of data is required to do both the hydrogen generation rate calculation and the flammability level evaluation. For tank waste that does not have sample-based data, a statistical-based value from probability distribution regression was used based on data from tanks belonging to a similar waste group. This report (Revision 3) updates the input data of hydrogen generation rates calculation for 177 tanks using the waste composition information in the Best-Basis Inventory Detail

  16. Steady State Flammable Gas Release Rate Calculation and Lower Flammability Level Evaluation for Hanford Tank Waste

    Energy Technology Data Exchange (ETDEWEB)

    HU, T.A.

    2000-04-27

    This work is to assess the steady-state flammability level at normal and off-normal ventilation conditions in the tank dome space for 177 double-shell and single-shell tanks at Hanford. Hydrogen generation rate was calculated for 177 tanks using rate equation model developed recently.

  17. 49 CFR 193.2059 - Flammable vapor-gas dispersion protection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Flammable vapor-gas dispersion protection. 193... Flammable vapor-gas dispersion protection. Each LNG container and LNG transfer system must have a dispersion... § 193.2013) with the following exceptions: (a) Flammable vapor-gas dispersion distances must be...

  18. Slurry growth, gas retention, and flammable gas generation by Hanford radioactive waste tanks: Synthetic waste studies, FY 1991

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, S.A.; Pederson, L.R.; Ryan, J.L.; Scheele, R.D.; Tingey, J.M.

    1992-08-01

    Of 177 high-level waste storage tanks on the Hanford Site, 23 have been placed on a safety watch list because they are suspected of producing flammable gases in flammable or explosive concentrate. One tankin particular, Tank 241-SY-101 (Tank 101-SY), has exhibited slow increases in waste volume followed by a rapid decrease accompanied by venting of large quantities of gases. The purpose of this study is to help determine the processes by which flammable gases are produced, retained, and eventually released from Tank 101-SY. Waste composition data for single- and double-shell waste tanks on the flammable gas watch listare critically reviewed. The results of laboratory studies using synthetic double-shell wastes are summarized, including physical and chemical properties of crusts that are formed, the stoichiometry and rate ofgas generation, and mechanisms responsible for formation of a floating crust.

  19. 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.

  20. 77 FR 62224 - Hanford Tank Farms Flammable Gas Safety Strategy

    Science.gov (United States)

    2012-10-12

    ... tanks' headspace. A significant flammable gas accident would have considerable radiological consequences... inventory of the tanks and (2) the amount of waste that could be released in a major accident...] [FR Doc No: 2012-25064] DEFENSE NUCLEAR FACILITIES SAFETY BOARD [Recommendation 2012-2] Hanford...

  1. Evaluation of 241 AN tank farm flammable gas behavior

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, D.A.

    1994-01-01

    The 241 AN Tank Farm tanks 241-AN-103, -104, and 105 are Flammable Gas Watch List tanks. Characteristics exhibited by these tanks (i.e., surface level drops, pressure increases, and temperature profiles) are similar to those exhibited by tank 241-SY-101, which is also a Watch List tank. Although the characteristics exhibited by tank 241-SY-101 are also present in tanks 241-AN-103, -104, and 105, they are exhibited to a lesser degree in the AN Tank Farm tanks. The 241 AN Tank Farm tanks have only small surface level drops, and the pressure changes that occur are not sufficient to release an amount of gas that would cause the dome space to exceed the lower flammability limit (LFL) for hydrogen. Therefore, additional restrictions are probably unnecessary for working within the 241 AN Tank Farm, either within the dome space of the tanks or in the waste.

  2. A risk-based approach to flammable gas detector spacing.

    Science.gov (United States)

    Defriend, Stephen; Dejmek, Mark; Porter, Leisa; Deshotels, Bob; Natvig, Bernt

    2008-11-15

    Flammable gas detectors allow an operating company to address leaks before they become serious, by automatically alarming and by initiating isolation and safe venting. Without effective gas detection, there is very limited defense against a flammable gas leak developing into a fire or explosion that could cause loss of life or escalate to cascading failures of nearby vessels, piping, and equipment. While it is commonly recognized that some gas detectors are needed in a process plant containing flammable gas or volatile liquids, there is usually a question of how many are needed. The areas that need protection can be determined by dispersion modeling from potential leak sites. Within the areas that must be protected, the spacing of detectors (or alternatively, number of detectors) should be based on risk. Detector design can be characterized by spacing criteria, which is convenient for design - or alternatively by number of detectors, which is convenient for cost reporting. The factors that influence the risk are site-specific, including process conditions, chemical composition, number of potential leak sites, piping design standards, arrangement of plant equipment and structures, design of isolation and depressurization systems, and frequency of detector testing. Site-specific factors such as those just mentioned affect the size of flammable gas cloud that must be detected (within a specified probability) by the gas detection system. A probability of detection must be specified that gives a design with a tolerable risk of fires and explosions. To determine the optimum spacing of detectors, it is important to consider the probability that a detector will fail at some time and be inoperative until replaced or repaired. A cost-effective approach is based on the combined risk from a representative selection of leakage scenarios, rather than a worst-case evaluation. This means that probability and severity of leak consequences must be evaluated together. In marine and

  3. An approximate-reasoning-based method for screening flammable gas tanks

    Energy Technology Data Exchange (ETDEWEB)

    Eisenhawer, S.W.; Bott, T.F.; Smith, R.E.

    1998-03-01

    High-level waste (HLW) produces flammable gases as a result of radiolysis and thermal decomposition of organics. Under certain conditions, these gases can accumulate within the waste for extended periods and then be released quickly into the dome space of the storage tank. As part of the effort to reduce the safety concerns associated with flammable gas in HLW tanks at Hanford, a flammable gas watch list (FGWL) has been established. Inclusion on the FGWL is based on criteria intended to measure the risk associated with the presence of flammable gas. It is important that all high-risk tanks be identified with high confidence so that they may be controlled. Conversely, to minimize operational complexity, the number of tanks on the watchlist should be reduced as near to the true number of flammable risk tanks as the current state of knowledge will support. This report presents an alternative to existing approaches for FGWL screening based on the theory of approximate reasoning (AR) (Zadeh 1976). The AR-based model emulates the inference process used by an expert when asked to make an evaluation. The FGWL model described here was exercised by performing two evaluations. (1) A complete tank evaluation where the entire algorithm is used. This was done for two tanks, U-106 and AW-104. U-106 is a single shell tank with large sludge and saltcake layers. AW-104 is a double shell tank with over one million gallons of supernate. Both of these tanks had failed the screening performed by Hodgson et al. (2) Partial evaluations using a submodule for the predictor likelihood for all of the tanks on the FGWL that had been flagged previously by Whitney (1995).

  4. STEADY STATE FLAMMABLE GAS RELEASE RATE CALCULATION & LOWER FLAMMABILITY LEVEL EVALUATION FOR HANFORD TANK WASTE

    Energy Technology Data Exchange (ETDEWEB)

    HU, T.A.

    2005-10-27

    Assess the steady-state flammability level at normal and off-normal ventilation conditions. The hydrogen generation rate was calculated for 177 tanks using the rate equation model. Flammability calculations based on hydrogen, ammonia, and methane were performed for 177 tanks for various scenarios.

  5. STEADY STATE FLAMMABLE GAS RELEASE RATE CALCULATION AND LOWER FLAMMABILITY LEVEL EVALUATION FOR HANFORD TANK WASTE

    Energy Technology Data Exchange (ETDEWEB)

    HU TA

    2009-10-26

    Assess the steady-state flammability level at normal and off-normal ventilation conditions. The hydrogen generation rate was calculated for 177 tanks using the rate equation model. Flammability calculations based on hydrogen, ammonia, and methane were performed for 177 tanks for various scenarios.

  6. Flammable gas tank waste level reconcilliation for 241-SX-102

    Energy Technology Data Exchange (ETDEWEB)

    Brevick, C.H.; Gaddie, L.A.

    1997-06-23

    Fluoro Dynel Northwest (FDNW) was authorized to address flammable gas issues by reconciling the unexplained surface level increases in Tank 24 1-S-1 1 1 (S-I 1 1, typical). The trapped gas evaluation document (ref 1) states that Tank SX-102 exceeds the 25% of the lower flammable limit (FL) criterion (ref 2), based on a surface level rise evaluation. The Waste Storage Tank Status and Leak Detection Criteria document, commonly referred to as the ``Wallet Report`` is the basis for this letter report (ref 3). The Wallet Report is also a part of the trapped gas evaluation document criteria. The Wallet Report contains various tank information, including: physical information, status, levels, and dry wells, see Appendix A. The unexplained waste level rises were attributed to the production and retention of gas in the column of waste corresponding to the unacquainted for surface level rise. From 1973 through 1980, the Wallet Report tracked Tank S- 102 transfers and reported a net cumulative change of 19.95 in. This surface level increase is from an unknown source or is unacquainted for. Duke Engineering and Services Hanford (DASH) and Leached Martin Hanford Corporation (LMHC) are interested in determining the validity of the unexplained surface level changes reported in the 0611e Wallet Report based upon other corroborative sources of data. The purpose of this letter report is to assemble detailed surface level and waste addition data from daily tank records, logbooks, and other corroborative data that indicate surface levels, and to reconcile the cumulative unacquainted for surface level changes as shown in the Wallet Report from 1973 through 1980.

  7. Methodology for Predicting Flammable Gas Mixtures in Double Contained Receiver Tanks [SEC 1 THRU SEC 3

    Energy Technology Data Exchange (ETDEWEB)

    HEDENGREN, D.C.

    2000-01-31

    This methodology document provides an estimate of the maximum concentrations of flammable gases (ammonia, hydrogen, and methane) which could exist in the vapor space of a double-contained receiver tank (DCRT) from the simultaneous saltwell pumping of one or more single-shell tanks (SSTs). This document expands Calculation Note 118 (Hedengren et a1 1997) and removes some of the conservatism from it, especially in vapor phase ammonia predictions. The methodologies of Calculation Note 118 (Hedengren et a1 1997) are essentially identical for predicting flammable gas mixtures in DCRTs from saltwell pumping for low DCRT ventilation rates, 1e, < 1 cfm. The hydrogen generation model has also been updated in the methodology of this document.

  8. Learning Equipment for the Flammability Limits of Liquefied Petroleum Gas

    Directory of Open Access Journals (Sweden)

    Siriratchanee Sirisawat

    2012-01-01

    Full Text Available Problem statement: This article was developing learning equipment for flammability limit behavior which designed for study the relation of Liquefied Petroleum Gas (LPG and combustion. The equipment can be use as an instructional media for obviously experiment of combustion. Approach: The test chamber was designed by using the stainless as a structure. The mirror with safety film was used for safety purpose to the tester. The mirror was the additional equipment for the ignition vision. The size of test chamber was 40×25×20 cm. The top of chamber can be opened when the ignition was occurred to reduce the inner pressure that can break the mirror or can be a cause of damage to other parts. The 2 of stainless plates with the size of 15×40 cm. were used and the hinges were attached at the upper edges of the chamber from both sides. The metal was closely attached at the chamber edge to reduce the leak of fuel to outer environment. The bottom structure of the chamber installs the control mainboard of electronics system and motor. The control of heat gain system inside the heat chamber. Results: The test chamber is designed to demonstrate the ignition. So, the size has to be suitably designed and large enough for convenience in monitoring. It can be seen that when the test is conducted in a real system, the result is extremely differed from the theory. The reason is the experimentation by the theory using the cup burner or a cylindrical glass cup. This cup has an outside diameter of 28 mm. and around the cup tunnel has an inside diameter of 8.5 or 9.5 cm with 53.5 cm. of height. The ratios of both testing equipments are extremely differed, so there is an opportunity that the accuracy is highly shifted. Conclusion: The test chamber shows that the flammability limit of LPG vary with temperature and can be compare with burgess-wheeler law. This law mentioned “LFL and UFL is relative with the chemical in Paraffin Hydrocarbon (Alkane Group in

  9. 46 CFR 35.30-40 - Flammable liquid and gas fuels as ship's stores-TB/ALL.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Flammable liquid and gas fuels as ship's stores-TB/ALL... OPERATIONS General Safety Rules § 35.30-40 Flammable liquid and gas fuels as ship's stores—TB/ALL. Flammable liquids and gases other than diesel fuel, to be used as fuel for approved equipment must satisfy...

  10. Resolve! Version 2.5: Flammable Gas Accident Analysis Tool Acceptance Test Plan and Test Results

    Energy Technology Data Exchange (ETDEWEB)

    LAVENDER, J.C.

    2000-10-17

    RESOLVE! Version 2 .5 is designed to quantify the risk and uncertainty of combustion accidents in double-shell tanks (DSTs) and single-shell tanks (SSTs). The purpose of the acceptance testing is to ensure that all of the options and features of the computer code run; to verify that the calculated results are consistent with each other; and to evaluate the effects of the changes to the parameter values on the frequency and consequence trends associated with flammable gas deflagrations or detonations.

  11. Flammable gas issues in double-contained receiver tanks. Revision 2

    Energy Technology Data Exchange (ETDEWEB)

    Peurrung, L.M.; Mahoney, L.A.; Stewart, C.W.; Gauglitz, P.A.; Pederson, L.R.; Bryan, S.A.; Shepard, C.L.

    1998-08-01

    Four double-contained receiver tanks (DCRTs) at Hanford will be used to store salt-well pumped liquids from tanks on the Flammable Gas Watch List. This document was created to serve as a reference document describing the current knowledge of flammable gas issues in DCRTs. The document identifies, describes, evaluates, and attempts to quantify potential gas carryover and release mechanisms. It estimates several key parameters needed for these calculations, such as initial aqueous concentrations and ventilation rate, and evaluates the uncertainty in those estimates. It justifies the use of the Schumpe model for estimating vapor-liquid equilibrium constants. It identifies several potential waste compatibility issues (such as mixing and pH or temperature changes) that could lead to gas release and provides a basis for calculating their effects. It evaluates the potential for gas retention in precipitated solids within a DCRT and whether retention could lead to a buoyant displacement instability (rollover) event. It discusses rates of radiolytic, thermal, and corrosive hydrogen generation within the DCRT. It also describes in detail the accepted method of calculating the lower flammability limit (LFL) for mixtures of flammable gases. The report incorporates these analyses into two models for calculating headspace flammability, one based on instantaneous equilibrium between dissolved gases and the headspace and one incorporating limited release rates based on mass-transfer considerations. Finally, it demonstrates the use of both models to estimate headspace flammable gas concentrations and minimum ventilation rates required to maintain concentrations below 25% of the LFL.

  12. Electrical safety in flammable gas/vapor laden atmospheres

    CERN Document Server

    Korver, WOE

    1992-01-01

    This book provides comprehensive coverage of electrical system installation within areas where flammable gases and liquids are handled and processed. The accurate hazard evaluation of flammability risks associated with chemical and petrochemical locations is critical in determining the point at which the costs of electrical equipment and installation are balanced with explosion safety requirements. The book offers the most current code requirements along with tables and illustrations as analytic tools. Environmental characteristics are covered in Section 1 along with recommended electrical ins

  13. Summary of flammable gas hazard and potential consequences in tank waste remediation system facility at the Hanford site

    Energy Technology Data Exchange (ETDEWEB)

    Van Vleet, R.J., Westinghouse Hanford

    1996-12-11

    This document provides a summary of the flammable gas program since 1992. It provides the best understanding of generation, retention, release of flammable gases. It gives a composition for each of the flammable gas tanks, calculates postulated concentrations in the event of a release, calculates the pressure obtained during a burn, and provides radiological and toxicological consequences. Controls from the analysis are found in WHC-SD-WM-SAR-067.

  14. Methods of Off-Gas Flammability Control for DWPF Melter Off-Gas System at Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Choi, A.S. [Westinghouse Savannah River Company, AIKEN, SC (United States); Iverson, D.C.

    1996-05-02

    Several key operating variables affecting off-gas flammability in a slurry-fed radioactive waste glass melter are discussed, and the methods used to prevent potential off-gas flammability are presented. Two models have played a central role in developing such methods. The first model attempts to describe the chemical events occurring during the calcining and melting steps using a multistage thermodynamic equilibrium approach, and it calculates the compositions of glass and calcine gases. Volatile feed components and calcine gases are fed to the second model which then predicts the process dynamics of the entire melter off-gas system including off-gas flammability under both steady state and various transient operating conditions. Results of recent simulation runs are also compared with available data

  15. Flammable gas issues in double-contained receiver tanks. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Peurrung, L.M.; Mahoney, L.A.; Stewart, C.W.; Gauglitz, P.A.; Pederson, L.R.; Bryan, S.A.; Shepard, C.L.

    1998-06-01

    Four double-contained receiver tanks (DCRTs) at Hanford will be used to store salt-well pumped liquids from tanks on the Flammable Gas Watch List. This document was created to serve as a technical basis or reference document for flammable gas issues in DCRTs. The document identifies, describes, evaluates, and attempts to quantify potential gas carryover and release mechanisms. It estimates several key parameters needed for these calculations, such as initial aqueous concentrations and ventilation rate, and evaluates the uncertainty in those estimates. It justifies the use of the Schumpe model for estimating vapor-liquid equilibrium constants. It identifies several potential waste compatibility issues (such as mixing and pH or temperature changes) that could lead to gas release and provides a basis for calculating their effects. It evaluates the potential for gas retention in precipitated solids within a DCRT and whether retention could lead to a buoyant displacement instability (rollover) event. It discusses rates of radiolytic, thermal, and corrosive hydrogen generation within the DCRT. It also describes in detail the accepted method of calculating the lower flammability limit (LFL) for mixtures of flammable gases.

  16. Flammable gas safety program. Analytical methods development: FY 1994 progress report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.A.; Clauss, S.; Grant, K.; Hoopes, V.; Lerner, B.; Lucke, R.; Mong, G.; Rau, J.; Wahl, K.; Steele, R.

    1994-09-01

    This report describes the status of developing analytical methods to account for the organic components in Hanford waste tanks, with particular focus on tanks assigned to the Flammable Gas Watch List. The methods that have been developed are illustrated by their application to samples obtained from Tank 241-SY-101 (Tank 101-SY).

  17. Operation of the multigap resistive plate chamber using a gas mixture free of flammable components

    CERN Document Server

    Akindinov, A; Antonioli, P; Arcelli, S; Basile, M; Cara Romeo, G; Cifarelli, Luisa; Cindolo, F; De Caro, A; De Pasquale, S; Di Bartolomeo, A; Fusco-Girard, M; Golovine, V; Guida, M; Hatzifotiadou, D; Kaidalov, A B; Kim, D H; Kim, D W; Kisselev, S M; Laurenti, G; Lee, K; Lee, S C; Lioublev, E; Luvisetto, M L; Margotti, A; Martemyanov, A N; Nania, R; Noferini, F; Otiougova, P; Pesci, A; Pinazza, O; Polozov, P A; Scapparone, E; Scioli, G; Sellitto, S B; Semeria, F; Smirnitsky, A V; Tchoumakov, M M; Usenko, E; Valenti, G; Voloshin, K G; Williams, M C S; Zagreev, B V; Zampolli, C; Zichichi, A

    2004-01-01

    We have investigated the operation of the multigap resistive plate chamber (MRPC) for the ALICE-TOF system with a gas mixture free of flammable components. Two different gas mixtures, with and without iso-C//4H//1//0 have been used to measure the performance of the MRPC. The efficiency, time resolution, total charge, and the fast to total charge ratio have been found to be comparable.

  18. DWPF Melter Off-Gas Flammability Assessment for Sludge Batch 9

    Energy Technology Data Exchange (ETDEWEB)

    Choi, A. S. [Savannah River Site (SRS), Aiken, SC (United States)

    2016-07-11

    The slurry feed to the Defense Waste Processing Facility (DWPF) melter contains several organic carbon species that decompose in the cold cap and produce flammable gases that could accumulate in the off-gas system and create potential flammability hazard. To mitigate such a hazard, DWPF has implemented a strategy to impose the Technical Safety Requirement (TSR) limits on all key operating variables affecting off-gas flammability and operate the melter within those limits using both hardwired/software interlocks and administrative controls. The operating variables that are currently being controlled include; (1) total organic carbon (TOC), (2) air purges for combustion and dilution, (3) melter vapor space temperature, and (4) feed rate. The safety basis limits for these operating variables are determined using two computer models, 4-stage cold cap and Melter Off-Gas (MOG) dynamics models, under the baseline upset scenario - a surge in off-gas flow due to the inherent cold cap instabilities in the slurry-fed melter.

  19. Flammable gas double shell tank expert elicitation presentations (Part A and Part B)

    Energy Technology Data Exchange (ETDEWEB)

    Bratzel, D.R.

    1998-04-17

    This document is a compilation of presentation packages and white papers for the Flammable Gas Double Shell Tank Expert Elicitation Workshop {number_sign}2. For each presentation given by the different authors, a separate section was developed. The purpose for issuing these workshop presentation packages and white papers as a supporting document is to provide traceability and a Quality Assurance record for future reference to these packages.

  20. Results of Vapor Space Monitoring of Flammable Gas Watch List Tanks

    Energy Technology Data Exchange (ETDEWEB)

    MCCAIN, D.J.

    2000-09-27

    This report documents the measurement of headspace gas concentrations and monitoring results from the Hanford tanks that have continuous flammable gas monitoring. The systems used to monitor the tanks are Standard Hydrogen Monitoring Systems. Further characterization of the tank off-gases was done with Gas Characterization systems and vapor grab samples. The background concentrations of all tanks are below the action level of 6250 ppm. Other information which can be derived from the measurements (such as generation rate, released rate, and ventilation rate) is also discussed.

  1. Flammable Gas Safety Program: actual waste organic analysis FY 1996 progress report; Flammable Gas Safety Program: actual waste organic analysis FY 1996 progress report

    Energy Technology Data Exchange (ETDEWEB)

    Clauss, S.A.; Grant, K.E.; Hoopes, V.; Mong, G.M.; Rau, J.; Steele, R.; Wahl, K.H.

    1996-09-01

    This report describes the status of optimizing analytical methods to account for the organic components in Hanford waste tanks, with emphasis on tanks assigned to the Flammable Gas Watch List. The methods developed are illustrated by their application to samples from Tanks 241-SY-103 and 241-S-102. Capability to account for organic carbon in Tank SY-101 was improved significantly by improving techniques for isolating organic constituents relatively free from radioactive contamination and by improving derivatization methodology. The methodology was extended to samples from Tank SY-103 and results documented in this report. Results from analyzing heated and irradiated SY-103 samples (Gas Generation Task) and evaluating methods for analyzing tank waste directly for chelators and chelator fragments are also discussed.

  2. An Improved Analytical Approach to Determine the Explosive Effects of Flammable Gas-Air Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J M

    2005-11-10

    The U.S. Department of Energy (DOE) Complex includes many sites and laboratories that store quantities of low-level, solid nuclear waste in drums and other types of shipping containers. The drums may be stored for long periods of time prior to being transported and final dispositioning. Based on the radioactivity (e.g., Pu{sup 239} equivalent), chemical nature (e.g. volatile organic compounds) and other characteristics of the stored waste, flammable gases may evolve. Documented safety analyses (DSAs) for storage of these drums must address storage and safety management issues to protect workers, the general public, and the environment. This paper discusses an improved analytical method for determining the explosion effects flammable gas-air mixtures as well as the subsequent accident phenomenology.

  3. Data Observations on Double Shell Tank (DST) Flammable Gas Watch List Tank Behavior

    Energy Technology Data Exchange (ETDEWEB)

    HEDENGREN, D.C.

    2000-09-28

    This report provides the data from the retained gas sampler, void fraction instrument, ball rheometer, standard hydrogen monitoring system, and other tank data pertinent to gas retention and release behavior in the waste stored in double-shelled Flammable Gas Watch List tanks at Hanford. These include tanks 241-AN-103,241-AN-104, 241-AN-105, 241-AW-101, 241-SY-101, and 241-SY-103. The tanks and the waste they contain are described in terms of fill history and chemistry. The results of mixer pump operation and recent waste transfers and back-dilution in SY-101 are also described. In-situ measurement and monitoring systems are described and the data are summarized under the categories of thermal behavior, waste configuration and properties, gas generation and composition, gas retention and historical gas release behavior.

  4. Evaluation of mitigation strategies in Facility Group 1 double-shell flammable-gas tanks at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Unal, C.; Sadasivan, P.; Kubic, W.L.; White, J.R.

    1997-11-01

    Radioactive nuclear waste at the Hanford Site is stored in underground waste storage tanks at the site. The tanks fall into two main categories: single-shell tanks (SSTs) and double-shell tanks (DSTs). There are a total of 149 SSTs and 28 DSTs. The wastes stored in the tanks are chemically complex. They basically involve various sodium salts (mainly nitrite, nitrate, carbonates, aluminates, and hydroxides), organic compounds, heavy metals, and various radionuclides, including cesium, strontium, plutonium, and uranium. The waste is known to generate flammable gas (FG) [hydrogen, ammonia, nitrous oxide, hydrocarbons] by complex chemical reactions. The process of gas generation, retention, and release is transient. Some tanks reach a quasi-steady stage where gas generation is balanced by the release rate. Other tanks show continuous cycles of retention followed by episodic release. There currently are 25 tanks on the Flammable Gas Watch List (FGWL). The objective of this report is to evaluate possible mitigation strategies to eliminate the FG hazard. The evaluation is an engineering study of mitigation concepts for FG generation, retention, and release behavior in Tanks SY-101, AN-103, AN 104, An-105, and Aw-101. Where possible, limited quantification of the effects of mitigation strategies on the FG hazard also is considered. The results obtained from quantification efforts discussed in this report should be considered as best-estimate values. Results and conclusions of this work are intended to help in establishing methodologies in the contractor`s controls selection analysis to develop necessary safety controls for closing the FG unreviewed safety question. The general performance requirements of any mitigation scheme are discussed first.

  5. An approximate-reasoning-based method for screening high-level waste tanks for flammable gas

    Energy Technology Data Exchange (ETDEWEB)

    Eisenhawer, S.W.; Bott, T.F.; Smith, R.E.

    1998-07-01

    The in situ retention of flammable gas produced by radiolysis and thermal decomposition in high-level waste can pose a safety problem if the gases are released episodically into the dome space of a storage tank. Screening efforts at Hanford have been directed at identifying tanks in which this situation could exist. Problems encountered in screening motivated an effort to develop an improved screening methodology. Approximate reasoning (AR) is a formalism designed to emulate the kinds of complex judgments made by subject matter experts. It uses inductive logic structures to build a sequence of forward-chaining inferences about a subject. AR models incorporate natural language expressions known as linguistic variables to represent evidence. The use of fuzzy sets to represent these variables mathematically makes it practical to evaluate quantitative and qualitative information consistently. The authors performed a pilot study to investigate the utility of AR for flammable gas screening. They found that the effort to implement such a model was acceptable and that computational requirements were reasonable. The preliminary results showed that important judgments about the validity of observational data and the predictive power of models could be made. These results give new insights into the problems observed in previous screening efforts.

  6. Development of a cost efficient methodology to perform allocation of flammable and toxic gas detectors applying CFD tools

    Energy Technology Data Exchange (ETDEWEB)

    Storch, Rafael Brod; Rocha, Gean Felipe Almeida [Det Norske Veritas (DNV), Rio de Janeiro, RJ (Brazil); Nalvarte, Gladys Augusta Zevallos [Det Norske Veritas (DNV), Novik (Norway)

    2012-07-01

    This paper is aimed to present a computational procedure for flammable and toxic gas detector allocation and quantification developed by DNV. The proposed methodology applies Computational Fluid Dynamics (CFD) simulations as well as operational and safety characteristics of the analyzed region to assess the optimal number of toxic and flammable gas detectors and their optimal location. A probabilistic approach is also used when applying the DNV software ThorEXPRESSLite, following NORSOK Z013 Annex G and presented in HUSER et al. 2000 and HUSER et al. 2001, when the flammable gas detectors are assessed. A DNV developed program, DetLoc, is used to run in an iterative way the procedure described above leading to an automatic calculation of the gas detectors location and number. The main advantage of the methodology presented above is the independence of human interaction in the gas detector allocation leading to a more precise and free of human judgment allocation. Thus, a reproducible allocation is generated when comparing several different analyses and a global criteria appliance is guaranteed through different regions in the same project. A case study is presented applying the proposed methodology. (author)

  7. An analysis of tank and pump pit flammable gas data in support of saltwater pumping safety basis simplification

    Energy Technology Data Exchange (ETDEWEB)

    MCCAIN, D.J.

    2000-07-26

    Hanford Site high-level waste tanks are interim stabilized by pumping supernatant and interstitial waste liquids to double-shell tanks (DSTs) through a saltwell pump (SWP). The motor to this SWP is located atop the tank, inside a pump pit. A pumping line extends down from the pump motor into the well area, located in the salt/sludge solids in the tank below. Pumping of these wastes is complicated by the fact that some of the wastes generate and retain potentially hazardous amounts of hydrogen, nitrous oxide, and ammonia. Monitoring of flammable gas concentrations during saltwell pumping activities has shown that one effect of pumping is acceleration in the release of accumulated hydrogen. A second effect is that of a temporarily increased hydrogen concentration in both the dome space and pump pit. There is a safety concern that the hydrogen concentration during saltwell pumping activities might approach the lower flammability limit (LFL) in either the tank dome space or the pump pit. The current Final Safety Analysis Report (FSAR) (CHG 2000) for saltwell pumping requires continuous flammable gas monitoring in both the pump pit and the tank vapor space during saltwell pumping. The FSAR also requires that portable exhauster fans be available by most of the passively ventilated tanks to be saltwell pumped in the event that additional air flow is required to dilute the headspace concentration of flammable gases to acceptable levels. The first objective of this analysis is to review the need for an auxiliary exhauster. Since the purpose of the exhauster is to diffuse unacceptably high flammable gas concentrations, discovery of an alternate method of accomplishing the same task may provide cost savings. The method reviewed is that of temporarily stopping the saltwell pumps. This analysis also examines the typical hydrogen concentration peaks and the rates of increase in hydrogen levels already witnessed in tanks during saltwell pumping activities. The historical data

  8. MELTER OFF-GAS FLAMMABILITY ASSESSMENT FOR DWPF ALTERNATE REDUCTANT FLOWSHEET OPTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Choi, A.

    2011-07-08

    Glycolic acid and sugar are being considered as potential candidates to substitute for much of the formic acid currently being added to the Defense Waste Processing Facility (DWPF) melter feed as a reductant. A series of small-scale melter tests were conducted at the Vitreous State Laboratory (VSL) in January 2011 to collect necessary data for the assessment of the impact of these alternate reductants on the melter off-gas flammability. The DM10 melter with a 0.021 m{sup 2} melt surface area was run with three different feeds which were prepared at SRNL based on; (1) the baseline formic/nitric acid flowsheet, (2) glycolic/formic/nitric acid flowsheet, and (3) sugar/formic/nitric acid flowsheet - these feeds will be called the baseline, glycolic, and sugar flowsheet feeds, respectively, hereafter. The actual addition of sugar to the sugar flowsheet feed was made at VSL before it was fed to the melter. For each feed, the DM10 was run under both bubbled (with argon) and non-bubbled conditions at varying melter vapor space temperatures. The goal was to lower its vapor space temperature from nominal 500 C to less than 300 C at 50 C increments and maintain steady state at each temperature at least for one hour, preferentially for two hours, while collecting off-gas data including CO, CO{sub 2}, and H{sub 2} concentrations. Just a few hours into the first test with the baseline feed, it was discovered that the DM10 vapor space temperature would not readily fall below 350 C simply by ramping up the feed rate as the test plan called for. To overcome this, ambient air was introduced directly into the vapor space through a dilution air damper in addition to the natural air inleakage occurring at the operating melter pressure of -1 inch H{sub 2}O. A detailed description of the DM10 run along with all the data taken is given in the report issued by VSL. The SRNL personnel have analyzed the DM10 data and identified 25 steady state periods lasting from 32 to 92 minutes for all

  9. Flammability limits of lithium-ion battery thermal runaway vent gas in air and the inerting effects of halon 1301

    Science.gov (United States)

    Karp, Matthew Eugene

    Lithium-ion (rechargeable) and lithium-metal (non-rechargeable) battery cells put aircraft at risk of igniting and fueling fires. Lithium batteries can be packed in bulk and shipped in the cargo holds of freighter aircraft; currently lithium batteries are banned from bulk shipment on passenger aircraft [1]. The federally regulated Class C cargo compartment extinguishing system's utilization of a 5 %vol Halon 1301 knockdown concentration and a sustained 3 %vol Halon 1301 may not be sufficient at inerting lithium-ion battery vent gas and air mixtures [2]. At 5 %vol Halon 1301 the flammability limits of lithium-ion premixed battery vent gas (Li-Ion pBVG) in air range from 13.80 %vol to 26.07 %vol Li-Ion pBVG. Testing suggests that 8.59 %vol Halon 1301 is required to render all ratios of the Li-Ion pBVG in air inert. The lower flammability limit (LFL) and upper flammability limit (UFL) of hydrogen and air mixtures are 4.95 %vol and 76.52 %vol hydrogen, respectively. With the addition of 10 %vol and 20 %vol Halon 1301 the LFL is 9.02 %vol and 11.55 %vol hydrogen, respectively, and the UFL is 45.70 %vol and 28.39 %vol hydrogen, respectively. The minimum inerting concentration (MIC) of Halon 1301 in hydrogen and air mixtures is 26.72 %vol Halon 1301 at 16.2 %vol hydrogen. The LFL and UFL of Li-Ion pBVG and air mixtures are 7.88 %vol and 37.14 %vol Li-Ion pBVG, respectively. With the addition of 5 %vol, 7 %vol, and 8 %vol Halon 1301 the LFL is 13.80 %vol, 16.15 %vol, and 17.62 % vol Li-Ion pBVG, respectively, and the UFL is 26.07 %vol, 23.31 %vol, and 21.84 %vol Li- Ion pBVG, respectively. The MIC of Halon 1301 in Li-Ion pBVG and air mixtures is 8.59 %vol Halon 1301 at 19.52 %vol Li-Ion pBVG. Le Chatelier's mixing rule has been shown to be an effective measure for estimating the flammability limits of Li-Ion pBVGes. The LFL has a 1.79 % difference while the UFL has a 4.53 % difference. The state of charge (SOC) affects the flammability limits in an apparent parabolic

  10. Investigation of flammable gas and thermal safety issues for retrieval of waste from Tank 241-AN-105

    Energy Technology Data Exchange (ETDEWEB)

    Caley, S.M.; Stewart, C.W.; Antoniak, Z.I.; Cuta, J.M.; Mahoney, L.A.; Panisko, F.E.

    1998-09-01

    The primary purpose of this report is to identify and resolve some of the flammable gas and thermal safety issues potentially associated with the retrieval of waste from Tank 241-AN-105 (AN-105), which is the first double-shell tank scheduled for waste retrieval at Hanford. The planned retrieval scenario includes the following steps in AN-105: (1) degas the tank using two submerged mixing pumps, (2) turn off the mixer pump(s) and allow any suspended solids to settle, (3) decant the supernatant to the intermediate feed staging tank(s) (IFSTs) (AP-102 and/or AP-104) using water/caustic dilution at the transfer pump inlet, (4) add the remaining dilution water/caustic to the slurry remaining in AN-105, (5) mix the tank with the mixer pump(s) until the soluble solids dissolve, (6) turn off the mixer pump(s) and let the insoluble solids settle, and (7) decant the new supernatant to the IFST(s), leaving the insoluble solids behind. Three waste retrieval safety issues are addressed in this report. They are (1) the controlled degassing of AN-105 to ensure that the headspace remains <25% of the lower flammability limit (LFL), (2) an assessment of how dissolved gas (mainly ammonia) released during the transfer of the supernatant in AN-105 to the IFSTs and the water/caustic dilution of the remaining slurry in AN-105 will affect the flammability in these tanks; and (3) an assessment of the maximum waste temperatures that might occur in AN-105 during retrieval operations.

  11. Challenges and methodology for safety analysis of a high-level waste tank with large periodic releases of flammable gas

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, J.N.; Pasamehmetoglu, K.O.; White, J.R. [Los Alamos National Lab., NM (United States); Stewart, C.W. [Pacific Northwest Lab., Richland, WA (United States)

    1994-07-01

    Tank 241-SY-101, located at the Department of Energy Hanford Site, has periodically released up to 10,000 ft{sup 3} of flammable gas. This release has been one of the highest-priority DOE operational safety problems. The gases include hydrogen and ammonia (fuels) and nitrous oxide (oxidizer). There have been many opinions regarding the controlling mechanisms for these releases, but demonstrating an adequate understanding of the problem, selecting a mitigation methodology, and preparing the safety analysis have presented numerous new challenges. The mitigation method selected for the tank was to install a pump that would mix the tank contents and eliminate the sludge layer believed to be responsible for the gas retention and periodic releases. This report will describe the principal analysis methodologies used to prepare the safety assessment for the installation and operation of the pump, and because this activity has been completed, it will describe the results of pump operation.

  12. Flammable gas/slurry growth unreviewed safety question:justification for continued operation for the tank farms at the Hanford site

    Energy Technology Data Exchange (ETDEWEB)

    Leach, C.E., Westinghouse Hanford

    1996-07-31

    This Justification for Continued Operation (JCO) provides a basis for continued operation in 176 high level waste tanks, double contained receiver tanks (DCRTs), catch tanks, 244-AR Vault, 242-S and 242-T Evaporators and inactive miscellaneous underground storage tanks (IMUSTs) relative to flammable gas hazards. Required controls are specified.

  13. Gas retention and release behavior in Hanford single-shell waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, C.W.; Brewster, M.E.; Gauglitz, P.A.; Mahoney, L.A.; Meyer, P.A.; Recknagle, K.P.; Reid, H.C.

    1996-12-01

    This report describes the current understanding of flammable gas retention and release in Hanford single-shell waste tanks based on theory, experimental results, and observations of tank behavior. The single-shell tanks likely to pose a flammable gas hazard are listed and described, and photographs of core extrusions and the waste surface are included. The credible mechanisms for significant flammable gas releases are described, and release volumes and rates are quantified as much as possible. The only mechanism demonstrably capable of producing large ({approximately}100 m{sup 3}) spontaneous gas releases is the buoyant displacement, which occurs only in tanks with a relatively deep layer of supernatant liquid. Only the double-shell tanks currently satisfy this condition. All release mechanisms believed plausible in single-shell tanks have been investigated, and none have the potential for large spontaneous gas releases. Only small spontaneous gas releases of several cubic meters are likely by these mechanisms. The reasons several other postulated gas release mechanisms are implausible or incredible are also given.

  14. Interstage Flammability Analysis Approach

    Science.gov (United States)

    Little, Jeffrey K.; Eppard, William M.

    2011-01-01

    The Interstage of the Ares I launch platform houses several key components which are on standby during First Stage operation: the Reaction Control System (ReCS), the Upper Stage (US) Thrust Vector Control (TVC) and the J-2X with the Main Propulsion System (MPS) propellant feed system. Therefore potentially dangerous leaks of propellants could develop. The Interstage leaks analysis addresses the concerns of localized mixing of hydrogen and oxygen gases to produce deflagration zones in the Interstage of the Ares I launch vehicle during First Stage operation. This report details the approach taken to accomplish the analysis. Specified leakage profiles and actual flammability results are not presented due to proprietary and security restrictions. The interior volume formed by the Interstage walls, bounding interfaces with the Upper and First Stages, and surrounding the J2-X engine was modeled using Loci-CHEM to assess the potential for flammable gas mixtures to develop during First Stage operations. The transient analysis included a derived flammability indicator based on mixture ratios to maintain achievable simulation times. Validation of results was based on a comparison to Interstage pressure profiles outlined in prior NASA studies. The approach proved useful in the bounding of flammability risk in supporting program hazard reviews.

  15. Flammability as an ecological and evolutionary driver

    Science.gov (United States)

    Pausas, Juli G.; Keeley, Jon E.; Schwilk, Dylan W.

    2017-01-01

    We live on a flammable planet yet there is little consensus on the origin and evolution of flammability in our flora.We argue that part of the problem lies in the concept of flammability, which should not be viewed as a single quantitative trait or metric. Rather, we propose that flammability has three major dimensions that are not necessarily correlated: ignitability, heat release and fire spread rate. These major axes of variation are controlled by different plant traits and have differing ecological impacts during fire.At the individual plant scale, these traits define three flammability strategies observed in fire-prone ecosystems: the non-flammable, the fast-flammable and the hot-flammable strategy (with low ignitability, high flame spread rate and high heat release, respectively). These strategies increase the survival or reproduction under recurrent fires, and thus, plants in fire-prone ecosystems benefit from acquiring one of them; they represent different (alternative) ways to live under recurrent fires.Synthesis. This novel framework based on different flammability strategies helps us to understand variability in flammability across scales, and provides a basis for further research.

  16. Flammable Gas Alarm System Based on ADAM-6017%基于ADAM-6017的可燃气体报警系统

    Institute of Scientific and Technical Information of China (English)

    王卫华; 赵庆云; 靳建水; 赵继安; 韩国栋

    2012-01-01

    利用智能型以太网I/O ADAM-6017的特性,以分布式控制方式构建某化工厂碳酸酯类等可燃气体报警系统,给出了系统的硬件架构和软件流程及其组态方式.%Basing on Ethernet I/O ADAM-6017 and distributed control mode, the flammable gas alarm system for carbonates in a chemical plant was proposed, including its hardware and software configuration and programming process.

  17. PRELIMINARY DISCUSS ON EXPLOSION SUPPRESSION TECHNIQUE OF FLAMMABLE GAS CLOUD%可燃气云抑爆技术初探

    Institute of Scientific and Technical Information of China (English)

    汪剑辉; 刘飞; 薛一江

    2011-01-01

    Tests indicate that the combustion reaction process of explosion can be refrained by spraying explosion suppression materials in the process of explosion triggered or initial explosion phrase of flammable gas cloud, then explosion reaction can be interrupted or explosion intensity will be weakened strongly. Inorganic powders, inactive gas, and water mist are excellent materials on explosion suppression, which are worthy of being used widely. The mechanisms on explosion suppression of flammable gas cloud were discussed, and the most important problems for subsequent study were pointed out, which provide the reference for the application of explosion suppression technology.%试验表明,在可燃气云爆炸引发过程或爆炸初始阶段,通过喷洒抑爆材料可抑制爆炸燃烧反应进程,继而中断爆炸反应或显著削弱爆炸强度.无机粉末、惰气和水雾是性价比较高的抑爆材料,具有大面积推广的价值.探讨了可燃气云的抑爆机理,并指出可燃气云抑爆技术后续研究中亟待解决的问题,为可燃气云抑爆技术的实际应用提供了技术参考.

  18. The Design of Flammable/Toxic Gas Detection Alert Contrd System%可燃/有毒气体检测报警控制系统设计

    Institute of Scientific and Technical Information of China (English)

    刘定伦

    2011-01-01

    Responding to hight requirement on flammable and toxic gas detection and alarm from petrochemical industry, introduce failure safety and fault tolerance design theory, the application of SIL3 system in flammable/toxic gas detection and alarm for butyl alcohol project in an alkali plant is illustrated, respectively illustrates the realization methods of the system in respects in software and hardware, and describes system module configuration, PLC program configuration and configuration of console software.%针对可燃/有毒气体检测报警在石化行业中的高端需求,引进失效安全与容错的设计思路.介绍了SIL3等级气体监控系统在某碱厂丁辛醇项目可燃有毒气体报警系统中的应用,并分别从软件和硬件方面阐述了该系统的实现方法,对系统模块配置、PLC程序的组态和编程以及工作站软件的组态作了描述.

  19. DEVELOPMENT OF AN ANTIFOAM TRACKING SYSTEM AS AN OPTION TO SUPPORT THE MELTER OFF-GAS FLAMMABILITY CONTROL STRATEGY AT THE DWPF

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, T.; Lambert, D.

    2014-08-27

    The Savannah River National Laboratory (SRNL) has been working with the Savannah River Remediation (SRR) Defense Waste Processing Facility (DWPF) in the development and implementation of an additional strategy for confidently satisfying the flammability controls for DWPF’s melter operation. An initial strategy for implementing the operational constraints associated with flammability control in DWPF was based upon an analytically determined carbon concentration from antifoam. Due to the conservative error structure associated with the analytical approach, its implementation has significantly reduced the operating window for processing and has led to recurrent Slurry Mix Evaporator (SME) and Melter Feed Tank (MFT) remediation. To address the adverse operating impact of the current implementation strategy, SRR issued a Technical Task Request (TTR) to SRNL requesting the development and documentation of an alternate strategy for evaluating the carbon contribution from antifoam. The proposed strategy presented in this report was developed under the guidance of a Task Technical and Quality Assurance Plan (TTQAP) and involves calculating the carbon concentration from antifoam based upon the actual mass of antifoam added to the process assuming 100% retention. The mass of antifoam in the Additive Mix Feed Tank (AMFT), in the Sludge Receipt and Adjustment Tank (SRAT), and in the SME is tracked by mass balance as part of this strategy. As these quantities are monitored, the random and bias uncertainties affecting their values are also maintained and accounted for. This report documents: 1) the development of an alternate implementation strategy and associated equations describing the carbon concentration from antifoam in each SME batch derived from the actual amount of antifoam introduced into the AMFT, SRAT, and SME during the processing of the batch. 2) the equations and error structure for incorporating the proposed strategy into melter off-gas flammability assessments

  20. Testing Vegetation Flammability: The Problem of Extremely Low Ignition Frequency and Overall Flammability Score

    Directory of Open Access Journals (Sweden)

    Zorica Kauf

    2014-01-01

    Full Text Available In the recent decades changes in fire regimes led to higher vulnerability of fire prone ecosystems, with vegetation being the only component influencing fire regime which can be managed in order to reduce probability of extreme fire events. For these management practices to be effective reliable information on the vegetation flammability is being crucial. Epiradiator based testing methods are one of the methods commonly used to investigate vegetation flammability and decrease in ignition frequency is always interpreted as a decrease in flammability. Furthermore, gathered information is often combined into a single flammability score. Here we present results of leaf litter testing which, together with previously conducted research on similar materials, show that material with very low ignition frequency under certain testing conditions can be extremely flammable if testing conditions are slightly changed. Additionally, our results indicate that combining measured information into one single flammability score, even though sometimes useful, is not always meaningful and should be performed with caution.

  1. The Design of the Ventilation Casing of the Auxiliary Facilities for the Flammable Gas Yest%可燃气体检定用配套设备通风罩设计

    Institute of Scientific and Technical Information of China (English)

    李献波

    2012-01-01

    Because of the danger in the test of the inflammable gas, we design the ventilation alarm set for the casing of the flammable gas test. The signal of the overflowing flammable gas for the test which tested by the gas density sensor set is witched into A/D and passed into the SCM. The density of the flammable gas vomited during the test is displaying on the LCD, which compared with the settled maximum of the density, when the density surpass the maximum, the ventilation set is switched on and the density of the flammable gas is regulated in time.%可燃气体报警器检定中,涉及的气体具有危险性,设计可燃气体检定罩通风报警装置,实验用溢出的可燃气体,经过气体浓度传感器检测后的信号进行A/D转换及处理,通过LCD实时显示检定过程中排放的可燃气体浓度值,并与设定的浓度上限值进行比较,当超过该浓度值时,启动通风装置以使室内的可燃气体浓度得到及时调节。

  2. 开敞空间工业气云爆炸研究进展%Analyses on industrial flammable gas cloud explosions

    Institute of Scientific and Technical Information of China (English)

    毕明树; 王树兰; 丁信伟

    2001-01-01

    Experimental results are introduced on unconfined gas explosions and the theoretical methods such as TNT equivalence model,multi_energy model,self_similar solution and computational fluid dynamics method are analyzed.The importance of restricts and obstacles to flammable gas cloud is demonstrated.The advantages and disadvantages of every method in the applications are evaluated.%评述了开敞空间气云爆炸的研究进展情况,阐明了约束条件和障碍物对气云爆炸威力的作用。分析了通过理论研究提出的TNT当量法、多能模型法、自相似法和数值模拟法,评价了它们在实际应用中的优越性和局限性。

  3. 国内外易燃易爆气体传感器的分类与比较%The classification and comparison of domestic and foreign gas sensors for flammable and explosive gas detection

    Institute of Scientific and Technical Information of China (English)

    褚云

    2014-01-01

    随着工业化进程的加快,为满足对易燃易爆气体监测的要求,简要介绍了气体传感器的重要性及其发展历程。根据其工作原理的不同将易燃易爆气体传感器分为六类,并阐述了各类气体传感器的工作原理、检测气体范围及优缺点分析。最后对各类传感器的性能指标进行了对比并对未来发展方向提出建议。%Due to the development of industrialization, there is an increasing demand for the detection of flammable and explosive gases.This paper briefly introduced the importance and history of gas sensors.Sensors targeting flam-mable and explosive gas were divided into six categories according to their working principles.The working princi-ple, manufacturing techniques, target gases, advantages and disadvantages of the sensors were demonstrated.Key performance factors were compared among each category and directions for future development were given in the end of the paper.

  4. Predictive Methods for Explosion Power of Irregular Flammable Gas Cloud%不规则可燃气云爆炸威力预测方法研究

    Institute of Scientific and Technical Information of China (English)

    喻健良; 闫兴清; 王健

    2014-01-01

    采用计算流体动力学(CFD )方法,以实际球罐区甲烷泄漏扩散形成的不规则可燃气云为研究工况,探讨了不规则气云爆炸威力的模拟方法,并对比了实际形状可燃气云、最大直径球可燃气云、重心高度球可燃气云、等体积球可燃气云以及采用 TNT 当量法计算得到的气云爆炸超压值。结果表明,TNT 当量法计算结果过于保守。等体积球、重心高度球、最大直径球与实际形状气云爆炸超压偏差分别为-13.9%、-17.2%、52.3%。采用等体积球法估算不规则可燃气云爆炸威力较为便捷,且精度较高。%The numerical method for explosion power of the irregular flammable gas cloud is discussed using the computa -tional fluid dynamics in the situation of leakage and dispersion of methane in real spherical tank .The explosion overpressures are obtained and compared among the five kinds of flammable gas clouds (FGC for short) ,including the actual geometrical FGC ,maximum diameter spherical FGC ,centre of gravity spherical FGC ,equal volume spherical FGC and the TNT equiva-lent FGC .The results indicate that the TNT equivalence method is too conservative .The errors of the equal volume spherical FGC ,the centre of gravity spherical FGC and the maximum diameter spherical FGC with the actual geometry FGC are -13 .9% ,-17 .2% and 52 .3% respectively .The predictive method of equal volume spherical FGC is simple and has a good accuracy .

  5. Report on the handling of safety information concerning flammable gases and ferrocyanide at the Hanford waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    This report discusses concerns safety issues, and management at Hanford Tank Farm. Concerns center on the issue of flammable gas generation which could ignite, and on possible exothermic reactions of ferrocyanide compounds which were added to single shell tanks in the 1950's. It is believed that information concerning these issues has been mis-handled and the problems poorly managed. (CBS)

  6. Flammability Assessment Methodology Program Phase I: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    C. A. Loehr; S. M. Djordjevic; K. J. Liekhus; M. J. Connolly

    1997-09-01

    The Flammability Assessment Methodology Program (FAMP) was established to investigate the flammability of gas mixtures found in transuranic (TRU) waste containers. The FAMP results provide a basis for increasing the permissible concentrations of flammable volatile organic compounds (VOCs) in TRU waste containers. The FAMP results will be used to modify the ''Safety Analysis Report for the TRUPACT-II Shipping Package'' (TRUPACT-II SARP) upon acceptance of the methodology by the Nuclear Regulatory Commission. Implementation of the methodology would substantially increase the number of drums that can be shipped to the Waste Isolation Pilot Plant (WIPP) without repackaging or treatment. Central to the program was experimental testing and modeling to predict the gas mixture lower explosive limit (MLEL) of gases observed in TRU waste containers. The experimental data supported selection of an MLEL model that was used in constructing screening limits for flammable VOC and flammable gas concentrations. The MLEL values predicted by the model for individual drums will be utilized to assess flammability for drums that do not meet the screening criteria. Finally, the predicted MLEL values will be used to derive acceptable gas generation rates, decay heat limits, and aspiration time requirements for drums that do not pass the screening limits. The results of the program demonstrate that an increased number of waste containers can be shipped to WIPP within the flammability safety envelope established in the TRUPACT-II SARP.

  7. Single Chip Sensing of Multiple Gas Flows

    CERN Document Server

    Bruschi, P; Piotto, M

    2008-01-01

    The fabrication and experimental characterization of a thermal flow meter, capable of detecting and measuring two independent gas flows with a single chip, is described. The device is based on a 4 x 4 mm2 silicon chip, where a series of differential micro-anemometers have been integrated together with standard electronic components by means of postprocessing techniques. The innovative aspect of the sensor is the use of a plastic adapter, thermally bonded to the chip, to convey the gas flow only to the areas where the sensors are located. The use of this inexpensive packaging procedure to include different sensing structures in distinct flow channels is demonstrated.

  8. Design and implementation of the NDIR instrument of flammable gas measure and alarm%非分光红外线吸收型可燃气体检测报警器的设计实现

    Institute of Scientific and Technical Information of China (English)

    朱成平; 罗耿

    2013-01-01

    The instrument of flammable gas measure and alarm has extremely important meaning to safety in production .Through studying the principle of the non -dispersive infra -red absorptive-type flammable gas detection technique , confirming the precision and stability of measure through experiment , completed the type selection of main sensor and components , designing the hardware circuit adapting to it, ensuring the whole dependability of the measurement system , and through validating of tests such as environment .%可燃气体检测报警器对安全生产有着极其重要的意义。通过研究非分光红外线吸收型可燃气体检测技术的原理,借助试验确定其测量精度和稳定性,完成了主要传感元件选型,设计出与其相适应的硬件电路,保证了系统的整体可靠性,现已通过环境等试验验证。

  9. Probabilistic consequence analysis for vapor cloud explosion of flammable gas%可燃气云爆炸事故后果的概率分析

    Institute of Scientific and Technical Information of China (English)

    陈国华; 周剑峰; 张文海; 张晖; 陈清光

    2006-01-01

    Consequence analysis is very important for risk evaluation. Vapor cloud explosion (VCE) is one of the main accident types of flammable gas. Because of the limitation of people's knowledge about accident consequence, influence of natural environment, and complex process of the development of an accident, some parameters of the VCE models can not be precisely defined, so that different input values can make great difference in the final results. A probabilistic consequence analysis method based on Monte-Carlo simulation (MCS) is proposed to help analyze the influence of an accident. How to evaluate the fatality radius when its probability is given is also analyzed, a regression estimate method based on Support Vector Machine (SVM) is proposed to solve this problem. The consequence severity can be reflected by the extent of damage (fatality radius, FR) and its related probability. Input arguments which have stochastic characteristic and their probability distributions are analyzed, and the application of the probabilistic consequence analysis method for VCE of LPG (liquefied petroleum gas) is illustrated.%对事故后果进行分析,是安全评价的重要内容.可燃气体泄漏后发生蒸气云爆炸是一种重要的事故类型,由于人们对事故后果认识的局限、环境的影响、以及事故发展过程的复杂性,VCE后果分析中许多参数未能准确定义,部份输入参数取值具有随机性,不同取值使最终的分析结果相差很大.本文提出了一种事故后果的概率分析方法,通过事故的后果(死亡半径)及其发生的概率来反映后果严重程度,并基于蒙特卡罗模拟方法来计算事故后果的发生概率.本文对给定发生概率时如何确定死亡半径也进行了分析,采用基于支持向量机(SVM)的非线性回归估计方法对死亡半径进行估计.分析了VCE后果分析模型中的随机性参数及其取值,结合具体的应用实例,说明了该方法在LPG储罐蒸气云爆炸后果分析中的应用.

  10. Effects of Globally Waste Disturbing Activities on Gas Generation, Retention, and Release in Hanford Waste Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Charles W.; Fountain, Matthew S.; Huckaby, James L.; Mahoney, Lenna A.; Meyer, Perry A.; Wells, Beric E.

    2005-08-02

    Various operations are authorized in Hanford single- and double-shell tanks that disturb all or a large fraction of the waste. These globally waste-disturbing activities have the potential to release a large fraction of the retained flammable gas and to affect future gas generation, retention, and release behavior. This report presents analyses of the expected flammable gas release mechanisms and the potential release rates and volumes resulting from these activities. The background of the flammable gas safety issue at Hanford is summarized, as is the current understanding of gas generation, retention, and release phenomena. Considerations for gas monitoring and assessment of the potential for changes in tank classification and steady-state flammability are given.

  11. 锥顶钢储罐内部可燃气体爆炸冲击荷载的 CFD 模拟%CFD simulation of internal flammable gas explosion loading in cone-roof steel tanks

    Institute of Scientific and Technical Information of China (English)

    胡可; 赵阳; 王震

    2015-01-01

    Steel tanks are widely used for the storage of liquefied natural gas,petroleum and other flammable explosive substance.The detonation of these explosives generates high intensity shock wave within a short time,which will cause serious damage to storage tanks and bring catastrophic results.A rational evaluation of the explosion loading is the foundation for structure failure analysis and safety designing of tanks.A CFD model was built up based on turbulence model and eddy dissipation concept(EDC)combustion model by use of computational fluid dynamics software Fluent, which can simulate the changes of explosion flow field in tanks and obtain the overpressure time history at typical positions.Compared with TNT equivalent method,the result by CFD model is closer to the actual situation of flammable gas explosion in tanks.Furthermore,the influences of height-to-diameter ratio,concentration and species of flammable gas and initial pressure were taken into account.It is shown that,the gas reaction rate and explosion loading enhance along with the increase of height-to-diameter ratio, initial pressure and activity of flammable gas. Moreover, a stoichiometric concentration will also cause a higher explosion pressure and gas reaction rate.%钢储罐常用于液化天然气、石油等易燃易爆物的储存,一旦起火爆炸,短时间内将产生极大的爆炸冲击波,造成储罐严重破坏并带来灾难性后果。爆炸冲击荷载的合理确定是钢储罐爆炸破坏分析与安全设计的重要基础。利用计算流体动力学 FLUENT 软件,基于 k -ε湍流模型和 EDC 燃烧模型,建立了能够模拟储罐内部爆炸流场变化情况的CFD 模型,获得了特定位置处的超压时程,与 TNT 当量模型相比其模拟结果更接近罐内可燃气体爆炸的实际情况。进一步考察了储罐高径比、可燃气体浓度与种类以及初始压力等因素对爆炸冲击荷载的影响。研究表明:储

  12. Methods for Gas Sensing with Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Kaul, Anupama B. (Inventor)

    2013-01-01

    Methods for gas sensing with single-walled carbon nanotubes are described. The methods comprise biasing at least one carbon nanotube and exposing to a gas environment to detect variation in temperature as an electrical response.

  13. 国内外关于混合气体可燃性及爆炸极限的标准化研究%Standardization Study of Gas Mixture Flammability and Explosion Limit at Home and Abroad

    Institute of Scientific and Technical Information of China (English)

    武丽娜; 陈睿谦

    2016-01-01

    The paper states the impacts of explosion limit on gas mixtures classification and the significance of classification to gas mixtures;and analyzes the relations of operating temperature and explosion limit and the correction method;and summarizes the distinguishment of flammability and standard cal-culating methods of explosion limits of different composition gas mixtures.Meanwhile, both the blind zones existing in domestic standards and the revision suggestions are provided with more secure and accurate reference data for the design and production of petrochemical industry .%阐述了爆炸极限对国内外可燃气体分类的影响及类别对可燃气体的意义,分析了操作温度与爆炸极限的关系及修正方法,总结了不同类型的混合气体可燃性的判别及爆炸极限计算的标准化方法,提出了国内标准中存在的盲区及修订盲区问题的建议,为石化行业的设计及生产提供更精确、更安全的参考数据。

  14. 关于可燃有毒气体探测报警系统合理设置方案的探讨%The Discussion of Flammable & Toxic Gas Detection Alarm System Set-up Plan

    Institute of Scientific and Technical Information of China (English)

    卢炜

    2016-01-01

    The article analyses the related standards, and based on the engineering practice, discusses the level evaluated of flammable & toxic gas detection alarm system within the layer of the process plant protection, and issued an reasonable hazardous gas detection alarm system frame. At the same time, focus on the real engineering practice environment, issued the practical set-up plan.%本文通过对相关标准规范的分析,结合工程实践过程中遇到的问题,论述了可燃气体探测、有毒气体探测报警系统在过程工厂中的保护层等级与实际效用,并据此提出了较为合理的有害气体探测报警系统的架构。同时针对目前实际状况,提出了可供实际操作的系统组成。

  15. Antimisting kerosene atomization and flammability

    Science.gov (United States)

    Fleeter, R.; Petersen, R. A.; Toaz, R. D.; Jakub, A.; Sarohia, V.

    1982-01-01

    Various parameters found to affect the flammability of antimisting kerosene (Jet A + polymer additive) are investigated. Digital image processing was integrated into a technique for measurement of fuel spray characteristics. This technique was developed to avoid many of the error sources inherent to other spray assessment techniques and was applied to the study of engine fuel nozzle atomization performance with Jet A and antimisting fuel. Aircraft accident fuel spill and ignition dynamics were modeled in a steady state simulator allowing flammability to be measured as a function of airspeed, fuel flow rate, fuel jet Reynolds number and polymer concentration. The digital imaging technique was employed to measure spray characteristics in this simulation and these results were related to flammability test results. Scaling relationships were investigated through correlation of experimental results with characteristic dimensions spanning more than two orders of magnitude.

  16. Self-Flammability of Gases Generated by Hanford Tank Waste and the Potential of Nitrogen Inerting to Eliminate Flammability Safety Concerns

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Lenna A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-10-12

    Through radiolytic and thermolytic reactions, Hanford tank wastes generate and retain a variety of gases, including hydrogen, nitrous oxide, methane (and other hydrocarbons), ammonia, and nitrogen. This gas generation can be expected to continue during processing in the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The generation rates in the WTP will change from those for the in-situ tank waste because of different process temperatures, different dose rates produced by in-process changes in the proportions of solid and liquid, and dilution of the waste liquid. The flammability of the generated gas that is continuously released, and of any retained gas that might be released into a vessel headspace in quantity due to a spontaneous release, depends on the concentrations not only of the fuel gases—primarily hydrogen (H2), methane, other hydrocarbons, and ammonia—but of the oxidizer nitrous oxide (N2O). As a result of high concentrations of N2O, some gas mixtures are “self-flammable” (i.e., ignition can occur when no air is present because N2O provides the only oxidizer needed). Self-flammability could potentially reduce the effectiveness of using a nitrogen (N2) purge in the headspace as a flammability control, if its effects are not accounted for. A given amount of inertant gas (N2) can accommodate only a certain amount of a generated self-flammable gas before the mixture with inertant gas becomes flammable.

  17. Nitrogen dilution effect on the flammability limits for hydrocarbons.

    Science.gov (United States)

    Chen, Chan-Cheng; Wang, Tzu-Chi; Liaw, Horng-Jang; Chen, Hui-Chu

    2009-07-30

    Theoretical models to predict the upper/lower flammability limits of hydrocarbons diluted with inert nitrogen gas are proposed in this study. It is found that there are linear relations between the reciprocal of the upper/lower flammability limits and the reciprocal of the molar fraction of hydrocarbon in the hydrocarbon/inert nitrogen mixture. Such linearity is examined by experimental data reported in the literature, which include the cases of methane, propane, ethylene and propylene. The R-squared values (R(2)) of the regression lines of the cases explored are all greater than 0.989 for upper flammability limit (UFL). The theoretical slope of the predictive line for lower flammability limit (LFL) is found to be very close to zero for all explored cases; and this result successfully explains the experimental fact that adding inert nitrogen to a flammable material has very limited effect on LFL. Because limit oxygen concentration (LOC) could be taken as the intersectional point of the UFL curve and LFL curve, a LOC-based method is proposed to predict the slope of the UFL curve when experimental data of UFL are not available. This LOC-based method predicts the UFL with average error ranging from 2.17% to 5.84% and maximum error ranging from 8.58% to 12.18% for the cases explored. The predictive models for inert gas of nitrogen are also extended to the case of inert gas other than nitrogen. Through the extended models, it was found that the inert ability of an inert gas depends on its mean molar heat capacity at the adiabatic flame temperature. Theoretical calculation shows that the inert abilities of carbon dioxide, steam, nitrogen and helium are in the following order: carbon dioxide>steam>nitrogen>helium; and this sequence conforms to the existing experimental data reported in the literature.

  18. Carbon dioxide dilution effect on flammability limits for hydrocarbons.

    Science.gov (United States)

    Chen, Chan-Cheng; Liaw, Horng-Jang; Wang, Tzu-Chi; Lin, Chin-Yu

    2009-04-30

    Theoretical models to predict the upper/lower flammability limits of a mixture composed of hydrocarbon and inert carbon dioxide are proposed in this study. It is found theoretically that there are linear relations between the reciprocal of the upper/lower flammability limits and the reciprocal of the molar fraction of hydrocarbon in the hydrocarbon/inert gas mixture. These theoretical linear relations are examined by existing experimental results reported in the literature, which include the cases of methane, propane, ethylene, and propylene. The coefficients of determination (R(2)) of the regression lines are found to be larger than 0.959 for all aforementioned cases. Thus, the proposed models are highly supported by existing experimental results. A preliminary study also shows the conclusions in present work have the possibility to extend to non-hydrocarbon flammable materials or to inert gas other than carbon dioxide. It is coincident that the theoretical model for the lower flammability limit (LFL) in present work is the same as the empirical model conjectured by Kondo et al.

  19. Flammability across the gymnosperm phylogeny: the importance of litter particle size.

    Science.gov (United States)

    Cornwell, William K; Elvira, Alba; van Kempen, Lute; van Logtestijn, Richard S P; Aptroot, André; Cornelissen, J Hans C

    2015-04-01

    Fire is important to climate, element cycles and plant communities, with many fires spreading via surface litter. The influence of species on the spread of surface fire is mediated by their traits which, after senescence and abscission, have 'afterlife' effects on litter flammability. We hypothesized that differences in litter flammability among gymnosperms are determined by litter particle size effects on litterbed packing. We performed a mesocosm fire experiment comparing 39 phylogenetically wide-ranging gymnosperms, followed by litter size and shape manipulations on two chemically contrasting species, to isolate the underlying mechanism. The first-order control on litter flammability was, indeed, litter particle size in both experiments. Most gymnosperms were highly flammable, but a prominent exception was the non-Pinus Pinaceae, in which small leaves abscised singly produced dense, non-flammable litterbeds. There are two important implications: first, ecosystems dominated by gymnosperms that drop small leaves separately will develop dense litter layers, which will be less prone to and inhibit the spread of surface litter fire. Second, some of the needle-leaved species previously considered to be flammable in single-leaf experiments were among the least flammable in litter fuel beds, highlighting the role of the litter traits of species in affecting surface fire regimes.

  20. Specimen Holder For Flammability Tests

    Science.gov (United States)

    Rucker, Michelle A.

    1992-01-01

    Fixture holds sheet specimens for flammability tests. Frame and clamps designed to minimize local overstress on specimen. Heat capacity of fixture low, interfering less with interpretation of results of test by drawing less heat away from specimen. Accepts films, fabrics, foams, and other sheets, rigid or flexible. Specimens thin or thick, or of variable thickness. Bent to accommodate curved rigid specimens. Also used for such other tests as particle-impact tests.

  1. A Single Nanobelt Transistor for Gas Identification: Using a Gas-Dielectric Strategy.

    Science.gov (United States)

    Cai, Bin; Song, Zhiqi; Tong, Yanhong; Tang, Qingxin; Shaymurat, Talgar; Liu, Yichun

    2016-06-21

    Despite tremendous potential and urgent demand in high-response low-cost gas identification, the development of gas identification based on a metal oxide semiconductor nanowire/nanobelt remains limited by fabrication complexity and redundant signals. Researchers have shown a multisensor-array strategy with "one key to one lock" configuration. Here, we describe a new strategy to create high-response room-temperature gas identification by employing gas as dielectric. This enables gas discrimination down to the part per billion (ppb) level only based on one pristine single nanobelt transistor, with the excellent average Mahalanobis distance (MD) as high as 35 at the linear discriminant analysis (LDA) space. The single device realizes the selective recognition function of electronic nose. The effect of the gas dielectric on the response of the multiple field-effect parameters is discussed by the comparative investigation of gas and solid-dielectric devices and the studies on trap density changes in the conductive channel. The current work opens up exciting opportunities for room-temperature gas recognition based on the pristine single device.

  2. A Single Nanobelt Transistor for Gas Identification: Using a Gas-Dielectric Strategy

    Directory of Open Access Journals (Sweden)

    Bin Cai

    2016-06-01

    Full Text Available Despite tremendous potential and urgent demand in high-response low-cost gas identification, the development of gas identification based on a metal oxide semiconductor nanowire/nanobelt remains limited by fabrication complexity and redundant signals. Researchers have shown a multisensor-array strategy with “one key to one lock” configuration. Here, we describe a new strategy to create high-response room-temperature gas identification by employing gas as dielectric. This enables gas discrimination down to the part per billion (ppb level only based on one pristine single nanobelt transistor, with the excellent average Mahalanobis distance (MD as high as 35 at the linear discriminant analysis (LDA space. The single device realizes the selective recognition function of electronic nose. The effect of the gas dielectric on the response of the multiple field-effect parameters is discussed by the comparative investigation of gas and solid-dielectric devices and the studies on trap density changes in the conductive channel. The current work opens up exciting opportunities for room-temperature gas recognition based on the pristine single device.

  3. Employing a cylindrical single crystal in gas-surface dynamics

    NARCIS (Netherlands)

    Hahn, C.; Shan, J.; Liu, Y.; Berg, van den O.; Kleijn, A.W.; Juurlink, L.B.F.

    2012-01-01

    We describe the use of a polished, hollow cylindrical nickel single crystal to study effects of step edges on adsorption and desorption of gas phase molecules. The crystal is held in an ultra-high vacuum apparatus by a crystal holder that provides axial rotation about a [100] direction, and a crysta

  4. Species composition and fire: non-additive mixture effects on ground fuel flammability

    Directory of Open Access Journals (Sweden)

    Cassandra eVan Altena

    2012-04-01

    Full Text Available Biodiversity effects on many aspects of ecosystem function have been well documented. However, fire is an exception: fire experiments have mainly included single species, bulk litter, or vegetation, and, as such, the role of biodiversity as a determinant of flammability, a crucial aspect of ecosystem function, is poorly understood. This study is the first to experimentally test whether flammability characteristics of two-species mixtures are non-additive, i.e. differ from expected flammability based on the component species in monoculture. In standardized fire experiments on ground fuels, including monocultures and mixtures of five contrasting subarctic plant fuel types in a controlled laboratory environment, we measured flame speed, flame duration and maximum temperature. Broadly half of the mixture combinations showed non-additive effects for these flammability indicators; these were mainly enhanced dominance effects, where the fuel types with the more flammable value for a characteristic determined the flammability of the whole mixture. The high incidence of species non-additive effects on ground fuel flammability suggest that the combinations of fuel types may have important effects on ground fire regimes in vegetations differing or changing in species composition.

  5. Off-site ignition probability of flammable gases.

    Science.gov (United States)

    Rew, P J; Spencer, H; Daycock, J

    2000-01-07

    A key step in the assessment of risk for installations where flammable liquids or gases are stored is the estimation of ignition probability. A review of current modelling and data confirmed that ignition probability values used in risk analyses tend to be based on extrapolation of limited incident data or, in many cases, on the judgement of those conducting the safety assessment. Existing models tend to assume that ignition probability is a function of release rate (or flammable gas cloud size) alone and they do not consider location, density or type of ignition source. An alternative mathematical framework for calculating ignition probability is outlined in which the approach used is to model the distribution of likely ignition sources and to calculate ignition probability by considering whether the flammable gas cloud will reach these sources. Data are collated on the properties of ignition sources within three generic land-use types: industrial, urban and rural. These data are then incorporated into a working model for ignition probability in a form capable of being implemented within risk analysis models. The sensitivity of the model results to assumptions made in deriving the ignition source properties is discussed and the model is compared with other available ignition probability methods.

  6. Plant traits determine forest flammability

    Science.gov (United States)

    Zylstra, Philip; Bradstock, Ross

    2016-04-01

    Carbon and nutrient cycles in forest ecosystems are influenced by their inherent flammability - a property determined by the traits of the component plant species that form the fuel and influence the micro climate of a fire. In the absence of a model capable of explaining the complexity of such a system however, flammability is frequently represented by simple metrics such as surface fuel load. The implications of modelling fire - flammability feedbacks using surface fuel load were examined and compared to a biophysical, mechanistic model (Forest Flammability Model) that incorporates the influence of structural plant traits (e.g. crown shape and spacing) and leaf traits (e.g. thickness, dimensions and moisture). Fuels burn with values of combustibility modelled from leaf traits, transferring convective heat along vectors defined by flame angle and with plume temperatures that decrease with distance from the flame. Flames are re-calculated in one-second time-steps, with new leaves within the plant, neighbouring plants or higher strata ignited when the modelled time to ignition is reached, and other leaves extinguishing when their modelled flame duration is exceeded. The relative influence of surface fuels, vegetation structure and plant leaf traits were examined by comparing flame heights modelled using three treatments that successively added these components within the FFM. Validation was performed across a diverse range of eucalypt forests burnt under widely varying conditions during a forest fire in the Brindabella Ranges west of Canberra (ACT) in 2003. Flame heights ranged from 10 cm to more than 20 m, with an average of 4 m. When modelled from surface fuels alone, flame heights were on average 1.5m smaller than observed values, and were predicted within the error range 28% of the time. The addition of plant structure produced predicted flame heights that were on average 1.5m larger than observed, but were correct 53% of the time. The over-prediction in this

  7. Remote flammable gas detection/measuring device.

    CSIR Research Space (South Africa)

    Kononov, VA

    1999-11-01

    Full Text Available stream_source_info COL601.pdf.txt stream_content_type text/plain stream_size 109 Content-Encoding ISO-8859-1 stream_name COL601.pdf.txt Content-Type text/plain; charset=ISO-8859-1 /var/dspace/dspace-run/assetstore/73...

  8. Sparse graphs are not flammable

    CERN Document Server

    Prałat, Paweł

    2012-01-01

    In this paper, we consider the following \\emph{$k$-many firefighter problem} on a finite graph $G=(V,E)$. Suppose that a fire breaks out at a given vertex $v \\in V$. In each subsequent time unit, a firefighter protects $k$ vertices which are not yet on fire, and then the fire spreads to all unprotected neighbours of the vertices on fire. The objective of the firefighter is to save as many vertices as possible. The surviving rate $\\rho(G)$ of $G$ is defined as the expected percentage of vertices that can be saved when a fire breaks out at a random vertex of $G$. Let $\\tau_k = k+2-\\frac {1}{k+2}$. We show that for any $\\eps >0$ and $k \\ge 2$, each graph $G$ on $n$ vertices with at most $(\\tau_k-\\eps)n$ edges is not flammable; that is, $\\rho(G) > \\frac {2\\eps}{5\\tau_k} > 0$. Moreover, a construction of a family of flammable random graphs is proposed to show that the constant $\\tau_k$ cannot be improved.

  9. The Numerical Simulation on Diffusion of Flammable Gas from Offshore Platform Vent System%海上平台冷放空可燃气体扩散的数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    张明; 王春升; 衣华磊; 陈绍凯; 钱惠增

    2011-01-01

    为研究烃类物质大气排放所引起的潜在危险,针对某海上平台建立模型,并应用FLUENT软件对平台冷放空泄放气体扩散过程进行了数值模拟研究.研究了可燃气体扩散的基本规律,分析了不同风向、风速、泄放量、冷放空管径、以及泄放口朝向对可燃气体扩散的影响,并将数值模拟结果与规范中的推荐值作了比较,并依据计算结果对冷放空管的设计提出了建议.%To study the potential hazards of flammable mixtures that result from atmospheric discharge of hydrocarbons, the numerical simulation on diffusion of flammable mixtures is carried out using FLUENT software. According to the dimensions of platform, the model is founded. The effect of wind direction, wind speed, discharge capacity, diameter of vent pipe and orientation of vent nozzle to the diffusion of flammable mixtures are analyzed in this paper. At last some proposals about the design of discharge system are made in this paper.

  10. Effect of Inhibitors on Biogas Laminar Burning Velocity and Flammability Limits in Spark Ignited Premix Combustion

    Directory of Open Access Journals (Sweden)

    Willyanto Anggono

    2014-01-01

    Full Text Available Biogas is the natural byproduct of the decomposition of vegetation or animal manure, of which there are almost in exhaustable supplies in the world, and which does not contribute CO2 or other greenhouse gases to global warming or climate change. Biogas contains 66.4% flammable gas (CH4 and 33.6% inhibitors (CO2 and N2. This study focuses on the effects of inhibitors on biogas laminar burning velocity and flammability limits in spark ignited premix combustion. Spherically expanding laminar premixed flames, freely propagating from spark ignition sources in initially quiescent biogas–air mixtures, are continuously recorded by a high-speed digital camera. Initially, all the experiments in this paper were performed using inhibitorless biogas (biogas without inhibitors at room temperature, at reduced pressure (0.5 atm and at various equivalence ratios (ϕ from the lower flammable limit to the upper flammable limit. The results are compared with those from biogas (containing inhibitors flames at reduced pressure, inhibitorless biogas flames at atmospheric pressure (1 atm, and biogas flames at atmospheric pressure to emphasize the effect of inhibitors on biogas laminar burning velocity and flammability limits. Compared to an inhibitorless biogas-air mixtures, in the biogas-air mixtures, the presence of inhibitors cause a reduction in the laminar burning velocity and the flammable limits become narrower.

  11. Selected Parametric Effects on Materials Flammability Limits

    Science.gov (United States)

    Hirsch, David B.; Juarez, Alfredo; Peyton, Gary J.; Harper, Susana A.; Olson, Sandra L.

    2011-01-01

    NASA-STD-(I)-6001B Test 1 is currently used to evaluate the flammability of materials intended for use in habitable environments of U.S. spacecraft. The method is a pass/fail upward flame propagation test conducted in the worst case configuration, which is defined as a combination of a material s thickness, test pressure, oxygen concentration, and temperature that make the material most flammable. Although simple parametric effects may be intuitive (such as increasing oxygen concentrations resulting in increased flammability), combinations of multi-parameter effects could be more complex. In addition, there are a variety of material configurations used in spacecraft. Such configurations could include, for example, exposed free edges where fire propagation may be different when compared to configurations commonly employed in standard testing. Studies involving combined oxygen concentration, pressure, and temperature on flammability limits have been conducted and are summarized in this paper. Additional effects on flammability limits of a material s thickness, mode of ignition, burn-length criteria, and exposed edges are presented. The information obtained will allow proper selection of ground flammability test conditions, support further studies comparing flammability in 1-g with microgravity and reduced gravity environments, and contribute to persuasive scientific cases for rigorous space system fire risk assessments.

  12. Mechanisms of gas retention and release: Experimental results for Hanford single-shell waste tanks 241-A-101, 241-S-106, and 241-U-103

    Energy Technology Data Exchange (ETDEWEB)

    Rassat, S.D.; Caley, S.M.; Bredt, P.R.; Gauglitz, P.A.; Rinehart, D.E.; Forbes, S.V.

    1998-09-01

    The 177 underground waste storage tanks at the Hanford Site contain millions of gallons of radioactive waste resulting from the purification of nuclear materials and related processes. Through various mechanisms, flammable gas mixtures of hydrogen, ammonia, methane, and nitrous oxide are generated and retained in significant quantities within the waste in many ({approximately}25) of these tanks. The potential for large releases of retained gas from these wastes creates a flammability hazard. It is a critical component of the effort to understand the flammability hazard and a primary goal of this laboratory investigation to establish an understanding of the mechanisms of gas retention and release in these wastes. The results of bubble retention experimental studies using waste samples from several waste tanks and a variety of waste types support resolution of the Flammable Gas Safety Issue. Gas bubble retention information gained in the pursuit of safe storage will, in turn, benefit future waste operations including salt-well pumping, waste transfers, and sluicing/retrieval.

  13. Flammability limits in flowing ethene-air-nitrogen mixtures: an experimental study

    NARCIS (Netherlands)

    Bolk, J.W.; Siccama, N.B.; Westerterp, K.R.

    1996-01-01

    A large pilot plant was constructed to study the upper flammability limit of ethene-air-nitrogen mixtures under conditions of flow. The gas mixtures flowed through an explosion tube with a length of 3.0 m and a diameter of 21 mm. An electrically heated wire was used as ignition source. Experiments w

  14. A Single-Walled Carbon Nanotube Network Gas Sensing Device

    Directory of Open Access Journals (Sweden)

    I-Ju Teng

    2011-08-01

    Full Text Available The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT networks. The SWCNT networks are synthesized on Al2O3-deposted SiO2/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD. The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO2 and NH3 vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO2 and 24 ppm for NH3.

  15. Influence of Knits Structure on Flammability and Comfortability

    Directory of Open Access Journals (Sweden)

    Mikučionienė D.

    2014-12-01

    Full Text Available Investigations of the influence of the knit structure, i.e. the loop length and the number of yarns in a loop, on flammability and comfortability are presented in this paper. The investigations were carried out using single jersey knits from Delta TA 18 tex × 2 yarns with five variants of a loop length. Single yarn as well as folded yarn from two single yarns was used in the investigations. Comparison of the results of single-layer knits flammability and air permeability with those of multilayer packet was made. The results obtained show that an increase in the loop length of the knit increases their permeability to air and decreases the burning time as well as increase in the number of layers decreases the air permeability and increases the burning time. Moreover, the similar burning time with significantly different permeability to air can be achieved changing the basic knitting parameters, i.e. the loop length and/or the yarn linear density.

  16. Unmanned Vehicle Material Flammability Test

    Science.gov (United States)

    Urban, David; Ruff, Gary A.; Fernandez-Pello, A. Carlos; T’ien, James S.; Torero, Jose L.; Cowlard, Adam; Rouvreau, Sebastian; Minster, Olivier; Toth, Balazs; Legros, Guillaume; Eigenbrod, Christian; Smirnov, Nickolay; Fujita, Osamu; Jomaas, Grande

    2013-01-01

    Microgravity combustion phenomena have been an active area of research for the past 3 decades however, there have been very few experiments directly studying spacecraft fire safety under low-gravity conditions. Furthermore, none of these experiments have studied sample and environment sizes typical of those expected in a spacecraft fire. All previous experiments have been limited to samples of the order of 10 cm in length and width or smaller. Terrestrial fire safety standards for all other habitable volumes on earth, e.g. mines, buildings, airplanes, ships, etc., are based upon testing conducted with full-scale fires. Given the large differences between fire behavior in normal and reduced gravity, this lack of an experimental data base at relevant length scales forces spacecraft designers to base their designs using 1-g understanding. To address this question a large scale spacecraft fire experiment has been proposed by an international team of investigators. This poster presents the objectives, status and concept of this collaborative international project to examine spacecraft material flammability at realistic scales. The concept behind this project is to utilize an unmanned spacecraft such as Orbital Cygnus vehicle after it has completed its delivery of cargo to the ISS and it has begun its return journey to earth. This experiment will consist of a flame spread test involving a meter scale sample ignited in the pressurized volume of the spacecraft and allowed to burn to completion while measurements are made. A computer modeling effort will complement the experimental effort. Although the experiment will need to meet rigorous safety requirements to ensure the carrier vehicle does not sustain damage, the absence of a crew removes the need for strict containment of combustion products. This will facilitate the examination of fire behavior on a scale that is relevant to spacecraft fire safety and will provide unique data for fire model validation. This will be

  17. 16 CFR Figure 2 to Part 1610 - Flammability Apparatus Views

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Flammability Apparatus Views 2 Figure 2 to Part 1610 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY OF CLOTHING TEXTILES Pt.1610, Fig. 2 Figure 2 to Part...

  18. 14 CFR 25.1727 - Flammable fluid shutoff means: EWIS.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flammable fluid shutoff means: EWIS. 25... Systems (EWIS) § 25.1727 Flammable fluid shutoff means: EWIS. EWIS associated with each flammable fluid shutoff means and control must be fireproof or must be located and protected so that any fire in a...

  19. Calibration assessment of forest flammability potential in Italy

    Directory of Open Access Journals (Sweden)

    Corona P

    2014-10-01

    Full Text Available Fuel flammability is defined as the relative ease with which a fuel will ignite and burn with a flame; different forest types have different intrinsic “baseline” flammabilities, depending on the susceptibility to burn of the main tree species that build up the forest cover. In this perspective, we apply a forest-type based approach to classify and map the flammability level of the forests in Italy. Baseline forest type-based flammability values provided at European level have been assigned to a national forest types map, derived from Corine Land Cover 2006; flammability values have been then further calibrated against the Burned Area Selection Ratio, a measure of the actual incidence of wildfires among different forest types. Accordingly, a calibrated flammability index was derived by simple linear regression, so that predicted flammability more accurately reflects observed fire incidence among different forest types in Italy. Findings show that the flammability of forest types ranges from low to high: on average, the 17% of the forest cover has medium to high flammability, with wide regional variability; notably, in four Regions (Sardegna, Sicilia, Puglia, Calabria over one third of total forest area has medium to high flammability. Large scale mapping of forest flammability is crucial to define long-term priorities among forest areas as to how to distribute fire management effort: areas falling into medium to high flammability classes should be given priority for implementing fuel management treatments in order to mitigate fire hazard from the stand to the landscape scale.

  20. Gas sensor array based on ceramic micro-hotplate for flammable gas detection%陶瓷微热板阵列式可燃气体传感器

    Institute of Scientific and Technical Information of China (English)

    薛严冰; 唐祯安

    2012-01-01

    works in the constant voltage heating mode, it can be used as a single sensor with good response to CO or CH4 gases. When the sensor array works at pulse voltage heating mode with alternating high or low working temperatures, it can realize quantitative detection for mixed gases of CO and CH4.

  1. Analysis of flammability in the attached buildings to containment under severe accident conditions

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, J.C. de la, E-mail: juan-carlos.de-la-rosa-blul@ec.europa.eu [European Commission Joint Research Centre (Netherlands); Fornós, Joan, E-mail: jfornosh@anacnv.com [Asociación Nuclear Ascó-Vandellós (Spain)

    2016-11-15

    Highlights: • Analysis of flammability conditions in buildings outside containment. • Stepwise approach easily applicable for any kind of containment and attached buildings layout. • Detailed application for real plant conditions has been included. - Abstract: Right after the events unfolded in Fukushima Daiichi, the European Union countries agreed in subjecting Nuclear Power Plants to Stress Tests as developed by WENRA and ENSREG organizations. One of the results as implemented in many European countries derived from such tests consisted of mandatory technical instructions issued by nuclear regulatory bodies on the analysis of potential risk of flammable gases in attached buildings to containment. The current study addresses the key aspects of the analysis of flammable gases leaking to auxiliary buildings attached to Westinghouse large-dry PWR containment for the specific situation where mitigating systems to prevent flammable gases to grow up inside containment are available, and containment integrity is preserved – hence avoiding isolation system failure. It also provides a full practical exercise where lessons learned derived from the current study – hence limited to the imposed boundary conditions – are applied. The leakage of gas from the containment to the support buildings is based on separate calculations using the EPRI-owned Modular Accident Analysis Program, MAAP4.07. The FATE™ code (facility Flow, Aerosol, Thermal, and Explosion) was used to model the transport and distribution of leaked flammable gas (H{sub 2} and CO) in the penetration buildings. FATE models the significant mixing (dilution) which occurs as the released buoyant gas rises and entrains air. Also, FATE accounts for the condensation of steam on room surfaces, an effect which acts to concentrate flammable gas. The results of the analysis show that during a severe accident, flammable conditions are unlikely to occur in compartmentalized buildings such as the one used in the

  2. Species composition and fire: non-additive Mixture effects on ground fuel flammability.

    NARCIS (Netherlands)

    Altena, C.; Logtestijn, R.S.P.; Cornwell, W.K.; Cornelissen, J.H.C.

    2012-01-01

    Diversity effects on many aspects of ecosystem function have been well documented. However, fire is an exception: fire experiments have mainly included single species, bulk litter, or vegetation, and, as such, the role of diversity as a determinant of flammability, a crucial aspect of ecosystem func

  3. Employing a cylindrical single crystal in gas-surface dynamics.

    Science.gov (United States)

    Hahn, Christine; Shan, Junjun; Liu, Ying; Berg, Otto; Kleijn, Aart W; Juurlink, Ludo B F

    2012-03-21

    We describe the use of a polished, hollow cylindrical nickel single crystal to study effects of step edges on adsorption and desorption of gas phase molecules. The crystal is held in an ultra-high vacuum apparatus by a crystal holder that provides axial rotation about a [100] direction, and a crystal temperature range of 89 to 1100 K. A microchannel plate-based low energy electron diffraction/retarding field Auger electron spectrometer (AES) apparatus identifies surface structures present on the outer surface of the cylinder, while a separate double pass cylindrical mirror analyzer AES verifies surface cleanliness. A supersonic molecular beam, skimmed by a rectangular slot, impinges molecules on a narrow longitudinal strip of the surface. Here, we use the King and Wells technique to demonstrate how surface structure influences the dissociation probability of deuterium at various kinetic energies. Finally, we introduce spatially-resolved temperature programmed desorption from areas exposed to the supersonic molecular beam to show how surface structures influence desorption features.

  4. Adsorption of two gas molecules at a single metal site in a metal–organic framework

    Energy Technology Data Exchange (ETDEWEB)

    Run; #269; evski, Tom; #269; e; Kapelewski, Matthew T.; Torres-Gavosto, Rodolfo M.; Tarver, Jacob D.; Brown, Craig M.; Long, Jeffrey R. (LBNL); (Delaware); (UCB); (NIST)

    2016-11-21

    One strategy to markedly increase the gas storage capacity of metal–organic frameworks is to introduce coordinatively-unsaturated metal centers capable of binding multiple gas molecules. Herein, we provide an initial demonstration that a single metal site within a framework can support the terminal coordination of two gas molecules—specifically hydrogen, methane, or carbon dioxide.

  5. Adsorption of two gas molecules at a single metal site in a metal–organic framework

    Energy Technology Data Exchange (ETDEWEB)

    Runčevski, Tomče; Kapelewski, Matthew T.; Torres-Gavosto, Rodolfo M.; Tarver, Jacob D.; Brown, Craig M.; Long, Jeffrey R.

    2016-01-01

    One strategy to markedly increase the gas storage capacity of metal-organic frameworks is to introduce coordinatively-unsaturated metal centers capable of binding multiple gas molecules. Herein, we provide an initial demonstration that a single metal site within a framework can support the terminal coordination of two gas molecules--specifically hydrogen, methane, or carbon dioxide.

  6. Pinning and gas oversaturation imply stable single surface nanobubbles

    NARCIS (Netherlands)

    Lohse, Detlef; Zhang, Xuehua

    2015-01-01

    Surface nanobubbles are experimentally known to survive for days at hydrophobic surfaces immersed in gas-oversaturated water. This is different from bulk nanobubbles, which are pressed out by the Laplace pressure against any gas oversaturation and dissolve in submilliseconds, as derived by Epstein a

  7. Method for Predicting Hypergolic Mixture Flammability Limits

    Science.gov (United States)

    2017-02-01

    AFRL-AFOSR-UK-TR-2017-0003 Method for Predicting Hypergolic Mixture Flammability Limits Laurent Catoire Ecole Nat Sup De Techniques Avancees Final...TASK NUMBER 5f.  WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Ecole Nat Sup De Techniques Avancees 828, Boulevard Des Marechaux...provides a mitigation strategy to reduce the risk of failure for the insertion of IL fuel technology into the small satellite market as AFRL/RQRP

  8. A theorem on the single particle energy in a Fermi gas with interaction

    NARCIS (Netherlands)

    Hugenholtz, N.M.; Hove, Léon van

    1958-01-01

    This paper investigates single particle properties in a Fermi gas with interaction at the absolute zero of temperature. In such a system a single particle energy has only a meaning for particles of momentum k close to the Fermi momentum kF. These single particle states are metastable with a life-tim

  9. A theorem on the single particle energy in a Fermi gas with interaction

    NARCIS (Netherlands)

    Hugenholtz, N.M.; Hove, Léon van

    1958-01-01

    This paper investigates single particle properties in a Fermi gas with interaction at the absolute zero of temperature. In such a system a single particle energy has only a meaning for particles of momentum k close to the Fermi momentum kF. These single particle states are metastable with a

  10. Estimation of Flammability Limits of Selected Fluorocarbons with F(sub 2) and CIF(sub3)

    Energy Technology Data Exchange (ETDEWEB)

    Trowbridge, L.D.

    1999-09-01

    During gaseous diffusion plant operations, conditions leading to the formation of flammable gas mixtures may occasionally arise. Currently, these could consist of the evaporative coolant CFC-114 and fluorinating agents such as F(sub 2) and CIF(sub 3). Replacement of CFC-114 with non-ozone-depleting substitutes such as c-C(sub 4)F(sub 8) and C(sub 4)F(sub 10) is planned. Consequently, in the future, these too must be considered potential ''fuels'' in flammable gas mixtures. Two questions of practical interest arise: (1) can a particular mixture sustain and propagate a flame if ignited, and (2) what is the maximum pressure that can be generated by the burning (and possibly exploding) gas mixture, should ignite? Experimental data on these systems are limited. To assist in answering these questions, a literature search for relevant data was conducted, and mathematical models were developed to serve as tools for predicting potential detonation pressures and estimating (based on empirical correlations between gas mixture thermodynamics and flammability for known systems) the composition limits of flammability for these systems. The models described and documented in this report are enhanced versions of similar models developed in 1992.

  11. TECHNICAL JUSTIFICATION FOR CHOOSING PROPANE AS A CALIBRATION AGENT FOR TOTAL FLAMMABLE VOLATILE ORGANIC COMPOUND (VOC) DETERMINATIONS

    Energy Technology Data Exchange (ETDEWEB)

    DOUGLAS, J.G.

    2006-07-06

    This document presents the technical justification for choosing and using propane as a calibration standard for estimating total flammable volatile organic compounds (VOCs) in an air matrix. A propane-in-nitrogen standard was selected based on a number of criteria: (1) has an analytical response similar to the VOCs of interest, (2) can be made with known accuracy and traceability, (3) is available with good purity, (4) has a matrix similar to the sample matrix, (5) is stable during storage and use, (6) is relatively non-hazardous, and (7) is a recognized standard for similar analytical applications. The Waste Retrieval Project (WRP) desires a fast, reliable, and inexpensive method for screening the flammable VOC content in the vapor-phase headspace of waste containers. Table 1 lists the flammable VOCs of interest to the WRP. The current method used to determine the VOC content of a container is to sample the container's headspace and submit the sample for gas chromatography--mass spectrometry (GC-MS) analysis. The driver for the VOC measurement requirement is safety: potentially flammable atmospheres in the waste containers must be allowed to diffuse prior to processing the container. The proposed flammable VOC screening method is to inject an aliquot of the headspace sample into an argon-doped pulsed-discharge helium ionization detector (Ar-PDHID) contained within a gas chromatograph. No actual chromatography is performed; the sample is transferred directly from a sample loop to the detector through a short, inert transfer line. The peak area resulting from the injected sample is proportional to the flammable VOC content of the sample. However, because the Ar-PDHID has different response factors for different flammable VOCs, a fundamental assumption must be made that the agent used to calibrate the detector is representative of the flammable VOCs of interest that may be in the headspace samples. At worst, we desire that calibration with the selected

  12. Flammability limits of silane/perfluorocarbon/nitrogen mixtures

    OpenAIRE

    Ohtani, Hideo

    2004-01-01

    Perfluorocarbons are known to react with silane because silane is a very strong reducing agent. However, quantitative information on their explosion limits are not known. So, in this study, flammability of silane/perfluorocarbon/nitrogen was examined experimentally. Their flammability areas were revealed quantitatively as triangular flammability diagrams, and the fact that perfluorocarbon reacts with silane was ascertained. (C) 2004 Elsevier Ltd.. All rights reserved.

  13. The Reseraches and Development Process of Flammable Ice%可燃冰的研究与开发进展

    Institute of Scientific and Technical Information of China (English)

    冯望生; 宋伟宾; 郑箭的; 张维滨; 腾兆健

    2013-01-01

    Flammable ice is commonly known as natural gas hydrate which is regarded as an alternative and clean energy in the 21st century. Flammable ice has a huge potential of development and utilization. The flammable ice's structural features, distribution, mining methods and difficulties in the mining process are comprehensively presented. The prospects for the future development of flammable ice is given finally. A range of problems to the environment will be taken with the development of flammable ice. It will take a long time to achieve industrial-scale and commercial exploitation.%  可燃冰是21世纪公认的替代能和清洁能,开发利用潜力巨大,是天然气水合物的俗称。综合介绍了可燃冰的概况、结构特征、分布情况、开采方法以及开采过程中的难点问题,最后对可燃冰的未来开发前景做了展望,开采可燃冰会给环境带来的一系列问题,要实现工业规模开采和商业化开采还需要一定的时间。

  14. Implementation of single-shot ellipsometry on gas gun experiments

    Science.gov (United States)

    Grant, Sean; Ao, Tommy; Bernstein, Aaron; Ditmire, Todd; Dolan, Dan; Lin, Jung-Fu; Seagle, Chris; Davis, Jean-Paul

    2017-01-01

    We have built and implemented a time-resolved ellipsometry diagnostic for dynamic material properties experiments at Sandia National Laboratories. This diagnostic measures the complex dielectric value of a sample experiencing dynamic compression, with a time resolution of a few nanoseconds. We show and discuss the dynamic ellipsometry measurements taken from shock loading experiments on a gas gun. This work is relevant to geophysical materials at high pressure-temperature conditions.

  15. Radial artery pseudoaneurysm: A rare complication after a single arterial puncture for blood-gas analysis.

    Science.gov (United States)

    Patel, Kajal Nitin; Gandhi, Shruti P; Sutariya, Harsh C

    2016-10-01

    With a reported incidence of 0.048%, radial artery pseudoaneurysm (PA) is a rare but serious complication of arterial cannulation. We report a case of PA developing after a single puncture of the right radial artery for arterial blood-gas analysis diagnosed by Doppler ultrasound in young male patient. The development of PA after puncture of radial artery for continuous blood pressure monitoring and serial blood-gas analysis has been reported in the past; however, to the best of our knowledge, there is only one case report of development of PA after a single arterial puncture for blood-gas analysis is reported in the past.

  16. Laboratory flammability studies of mixtures of hydrogen, nitrous oxide, and air

    Energy Technology Data Exchange (ETDEWEB)

    Cashdollar, K L; Hertzberg, M; Zlochower, I A; Lucci, C E; Green, G M; Thomas, R A [Bureau of Mines, Pittsburgh, PA (United States). Pittsburgh Research Center

    1992-06-26

    At the request of the Department of Energy and the Westinghouse Hanford Company, the Bureau of Mines has investigated the flammability of mixtures of hydrogen, nitrous oxide, and air. This work is relevant to the possible hazards of flammable gas generation from nuclear waste tanks at Hanford, WA. The tests were performed in a 120-L spherical chamber under both quiescent and turbulent conditions using both electric spark and pyrotechnic ignition sources. The data reported here for binary mixtures of hydrogen in air generally confirm the data of previous investigators, but they are more comprehensive than those reported previously. The results clarify to a greater extent the complications associated with buoyancy, turbulence, and selective diffusion. The data reported here for ternary mixtures of hydrogen and nitrous oxide in air indicate that small additions of nitrous oxide (relative to the amount of air) have little effect, but that higher concentrations of nitrous oxide (relative to air) significantly increase the explosion hazard.

  17. A Discussion of SY-101 Crust Gas Retention and Release Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    SD Rassat; PA Gauglitz; SM Caley; LA Mahoney; DP Mendoza

    1999-02-23

    The flammable gas hazard in Hanford waste tanks was made an issue by the behavior of double-shell Tank (DST) 241-SY-101 (SY-101). Shortly after SY-101 was filled in 1980, the waste level began rising periodically, due to the generation and retention of gases within the slurry, and then suddenly dropping as the gases were released. An intensive study of the tank's behavior revealed that these episodic releases posed a safety hazard because the released gas was flammable, and, in some cases, the volume of gas released was sufficient to exceed the lower flammability limit (LFL) in the tank headspace (Allemann et al. 1993). A mixer pump was installed in SY-101 in late 1993 to prevent gases from building up in the settled solids layer, and the large episodic gas releases have since ceased (Allemann et al. 1994; Stewart et al. 1994; Brewster et al. 1995). However, the surface level of SY-101 has been increasing since at least 1995, and in recent months the level growth has shown significant and unexpected acceleration. Based on a number of observations and measurements, including data from the void fraction instrument (VFI), we have concluded that the level growth is caused largely by increased gas retention in the floating crust. In September 1998, the crust contained between about 21 and 43% void based on VFI measurements (Stewart et al. 1998). Accordingly, it is important to understand the dominant mechanisms of gas retention, why the gas retention is increasing, and whether the accelerating level increase will continue, diminish or even reverse. It is expected that the retained gas in the crust is flammable, with hydrogen as a major constituent. This gas inventory would pose a flammable gas hazard if it were to release suddenly. In May 1997, the mechanisms of bubble retention and release from crust material were the subject of a workshop. The evaluation of the crust and potential hazards assumed a more typical void of roughly 15% gas. It could be similar to

  18. 30 CFR 57.4460 - Storage of flammable liquids underground.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Storage of flammable liquids underground. 57... AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES... liquids underground. (a) Flammable liquids shall not be stored underground, except— (1) Small quantities...

  19. Development of an automatic analyzer for explosion limit determination of flammable gas%可燃性气体爆炸极限自动测定仪的研制

    Institute of Scientific and Technical Information of China (English)

    熊焰; 孙立鑫; 赵会玲; 宋江闯

    2015-01-01

    目前关于爆炸极限测定的工业标准和实际测试装置由于实验教学安全等方面的限制,不太适合于实验教学,也不利于推广。本文介绍了一种可燃性气体爆炸极限自动测定实验装置,可用于测定可燃气体的爆炸极限配比范围,并可根据各项参数自动计算爆炸当量。该仪器可以自动进行气体配比,具有全自动程序控温功能,自动点火,装置小巧,可随意挪动,适合各个领域的爆炸实验研究。%T his paper introduces a combustible gas explosion limit automatic measurement experimen‐tal device that can be used to determine the proportion of combustible gas explosion limit range ,and calcu‐late the explosion equivalent. The instrument can ratio gas automatically with automatic temperature con‐trol function program ,automatic ignition .It is suitable for use of experimental research in various fields for the explosion.

  20. Real-time imaging of methane gas leaks using a single-pixel camera.

    Science.gov (United States)

    Gibson, Graham M; Sun, Baoqing; Edgar, Matthew P; Phillips, David B; Hempler, Nils; Maker, Gareth T; Malcolm, Graeme P A; Padgett, Miles J

    2017-02-20

    We demonstrate a camera which can image methane gas at video rates, using only a single-pixel detector and structured illumination. The light source is an infrared laser diode operating at 1.651μm tuned to an absorption line of methane gas. The light is structured using an addressable micromirror array to pattern the laser output with a sequence of Hadamard masks. The resulting backscattered light is recorded using a single-pixel InGaAs detector which provides a measure of the correlation between the projected patterns and the gas distribution in the scene. Knowledge of this correlation and the patterns allows an image to be reconstructed of the gas in the scene. For the application of locating gas leaks the frame rate of the camera is of primary importance, which in this case is inversely proportional to the square of the linear resolution. Here we demonstrate gas imaging at ~25 fps while using 256 mask patterns (corresponding to an image resolution of 16×16). To aid the task of locating the source of the gas emission, we overlay an upsampled and smoothed image of the low-resolution gas image onto a high-resolution color image of the scene, recorded using a standard CMOS camera. We demonstrate for an illumination of only 5mW across the field-of-view imaging of a methane gas leak of ~0.2 litres/minute from a distance of ~1 metre.

  1. Flammability limits in flowing ethene-air-nitrogen mixtures: an experimental study

    OpenAIRE

    Bolk, J.W.; Siccama, N.B.; Westerterp, K.R.

    1996-01-01

    A large pilot plant was constructed to study the upper flammability limit of ethene-air-nitrogen mixtures under conditions of flow. The gas mixtures flowed through an explosion tube with a length of 3.0 m and a diameter of 21 mm. An electrically heated wire was used as ignition source. Experiments were performed at pressures of 5 and 10 bar, with gas temperatures between 25 and 300 °C and with the wire fixed horizontally and vertically. Three different phenomena are observed: negligible react...

  2. A study on flammability limits of fuel mixtures.

    Science.gov (United States)

    Kondo, Shigeo; Takizawa, Kenji; Takahashi, Akifumi; Tokuhashi, Kazuaki; Sekiya, Akira

    2008-07-15

    Flammability limit measurements were made for various binary and ternary mixtures prepared from nine different compounds. The compounds treated are methane, propane, ethylene, propylene, methyl ether, methyl formate, 1,1-difluoroethane, ammonia, and carbon monoxide. The observed values of lower flammability limits of mixtures were found to be in good agreement to the calculated values by Le Chatelier's formula. As for the upper limits, however, some are close to the calculated values but some are not. It has been found that the deviations of the observed values of upper flammability limits from the calculated ones are mostly to lower concentrations. Modification of Le Chatelier's formula was made to better fit to the observed values of upper flammability limits. This procedure reduced the average difference between the observed and calculated values of upper flammability limits to one-third of the initial value.

  3. The Evaluation of Flammability Properties Regarding Testing Methods

    Directory of Open Access Journals (Sweden)

    Osvaldová Linda Makovická

    2015-12-01

    Full Text Available In this paper, we address the historical comparison methods with current methods for the assessment of flammability characteristics for materials an especially for wood, wood components and wooden buildings. Nowadays in European Union brings harmonization in evaluated of standards into each European country and try to make one concept of evaluated the flammability properties. In each European country to the one standard level which will be used by evaluation of materials regarding flammability. In our article we focused mainly on improving the evaluation methods in terms of flammability characteristics of using materials at building industry. In the article we present examples of different assessment methods at their own test methods in terms of fire prevention. On the base of old compared of materials by STN, BS and DIN methods for testing materials on fire and new methods of evaluating the flammability properties regarding EU standards before and after starting the flash over.

  4. Gain Scheduling Control of Gas Turbine Engines: Stability by Computing a Single Quadratic Lyapunov Function

    Science.gov (United States)

    2013-06-01

    STABILITY BY COMPUTING A SINGLE QUADRATIC LYAPUNOV FUNCTION Mehrdad Pakmehr∗ PhD Candidate Decision and Control Laboratory (DCL) School of Aerospace...linearization and linear matrix inequality (LMI) techniques. Using convex optimization tools, a single quadratic Lyapunov function is computed for multiple...Scheduling Control of Gas Turbine Engines: Stability by Computing a Single Quadratic Lyapunov Function 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  5. Kinetics of a single trapped ion in an ultracold buffer gas

    CERN Document Server

    Zipkes, Christoph; Sias, Carlo; Köhl, Michael

    2010-01-01

    The immersion of a single ion confined by a radiofrequency trap in an ultracold atomic gas extends the concept of buffer gas cooling to a new temperature regime. The steady state energy distribution of the ion is determined by its kinetics in the radiofrequency field rather than the temperature of the buffer gas. Moreover, the finite size of the ultracold gas facilitates the observation of back-action of the ion onto the buffer gas. We numerically investigate the system's properties depending on mass ratio, trap geometry, differential cross-section, and non-uniform neutral atom density distribution. We identify excess micromotion to set the typical scale for the ion energy statistics and explore the applicability of the mobility collision cross-section to the ultracold regime.

  6. Iridium single atom tips fabricated by field assisted reactive gas etching

    Science.gov (United States)

    Wood, John A.; Urban, Radovan; Salomons, Mark; Cloutier, Martin; Wolkow, Robert A.; Pitters, Jason L.

    2016-03-01

    We present a simple, reliable method to fabricate Ir single atom tips (SATs) from polycrystalline wire. An electrochemical etch in CaCl2 solution is followed by a field assisted reactive gas etch in vacuum at room temperature using oxygen as an etching gas and neon as an imaging gas. Once formed, SATs are cooled to liquid nitrogen temperatures and their underlying structure is examined through evaporation of the apex atoms. Furthermore, a method is developed to repair Ir SATs at liquid nitrogen temperatures when apex atoms evaporate. This method may be used to fabricate Ir SAT ion sources.

  7. DOE/DOE Tight Oil Flammability & Transportation Spill Safety

    Energy Technology Data Exchange (ETDEWEB)

    Lord, David L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-12-01

    This presentation describes crude oils, their phase behavior, the SPR vapor pressure program, and presents data comparisons from various analytical techniques. The overall objective is to describe physical properties of crude oil relevant to flammability and transport safety

  8. Single and Mixed Gas Adsorption Equilibria of Carbon Dioxide/Methane on Activated Carbon

    NARCIS (Netherlands)

    van der Vaart, R.; van der Vaart, Rick; Huiskes, Cindy; Bosch, H.; Reith, T.

    2000-01-01

    Single gas adsorption isotherms of methane and carbon dioxide on micro-porous Norit RB1 activated carbon were determined in a gravimetric analyser in the temperature range of 292 to 349 K and pressures to 0.8 Mpa. Furthermore binary isotherms of carbon dioxide and methane mixtures were determined at

  9. Isothermal currents in InSe, GaSe, and GaS single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Micocci, G.; Rizzo, A.; Tepore, A.; Zuanni, F. (Lecce Univ. (Italy). Ist. di Fisica)

    1983-11-16

    Isothermal current-time measurements are performed on InSe, GaSe, and GaS single crystals. The results reveal the presence of trapping centres and their activation energies and capture cross-sections are determined. The limitations of this method for the determination of trapping parameters in crystals are also discussed.

  10. Single ZnO Nanowire-Based Gas Sensors to Detect Low Concentrations of Hydrogen

    Directory of Open Access Journals (Sweden)

    Marlene N. Cardoza-Contreras

    2015-12-01

    Full Text Available Low concentrations of hazardous gases are difficult to detect with common gas sensors. Using semiconductor nanostructures as a sensor element is an alternative. Single ZnO nanowire gas sensor devices were fabricated by manipulation and connection of a single nanowire into a four-electrode aluminum probe in situ in a dual-beam scanning electron microscope-focused ion beam with a manipulator and a gas injection system in/column. The electrical response of the manufactured devices shows response times up to 29 s for a 121 ppm of H2 pulse, with a variation in the nanowire resistance appreciable at room temperature and at 373.15 K of approximately 8% and 14% respectively, showing that ZnO nanowires are good candidates to detect low concentrations of H2.

  11. Wireless gas sensing in South African underground platinum mines

    CSIR Research Space (South Africa)

    Abu-Mahfouz, Adnan M

    2014-04-01

    Full Text Available Approximately 70% of South African mines are classified as fiery, where methane gas potentially could cause explosions. The number of flammable gas reports and accidents are increasing steadily for both gold and platinum mines. However...

  12. Growth of single wall carbon nanotubes using PECVD technique: An efficient chemiresistor gas sensor

    Science.gov (United States)

    Lone, Mohd Yaseen; Kumar, Avshish; Husain, Samina; Zulfequar, M.; Harsh; Husain, Mushahid

    2017-03-01

    In this work, the uniform and vertically aligned single wall carbon nanotubes (SWCNTs) have been grown on Iron (Fe) deposited Silicon (Si) substrate by plasma enhanced chemical vapor deposition (PECVD) technique at very low temperature of 550 °C. The as-grown samples of SWCNTS were characterized by field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM) and Raman spectrometer. SWCNT based chemiresistor gas sensing device was fabricated by making the proper gold contacts on the as-grown SWCNTs. The electrical conductance and sensor response of grown SWCNTs have been investigated. The fabricated SWCNT sensor was exposed to ammonia (NH3) gas at 200 ppm in a self assembled apparatus. The sensor response was measured at room temperature which was discussed in terms of adsorption of NH3 gas molecules on the surface of SWCNTs. The achieved results are used to develope a miniaturized gas sensor device for monitoring and control of environment pollutants.

  13. Long-lasting dust rings in gas-rich disks: sculpting by single and multiple planets

    CERN Document Server

    Meru, Farzana; Reggiani, Maddalena; Baruteau, Clement; Pineda, Jaime E

    2014-01-01

    We propose a mechanism by which dust rings in protoplanetary disks can form and be long-lasting compared to gas rings. This involves the existence of a pressure maximum which traps dust either in between two gap-opening planets or at the outermost gap edge of a single or multiple planet system, combined with the decoupling of large dust particles from the gas. We perform 2D gas hydrodynamical simulations of disks with one and two giant planets which may open deep or partial gaps. A gas ring forms in between two planets such that the surface mass density is higher than on either side of it. This ring is a region of pressure maximum where we expect large grains, which are marginally coupled to the gas and would otherwise be subject to radial drift, to collect. Such a pressure maximum also occurs at the outermost gap edge in a disk with one or more planets. We infer the dust evolution in these regions as the gas disk evolves, to understand the longer term behavior of the resulting dust rings. Over time the gas s...

  14. Effect of a zero g environment on flammability limits as determined using a standard flammability tube apparatus

    Science.gov (United States)

    Strehlow, R. A.; Reuss, D. L.

    1980-01-01

    Flammability limits in a zero gravity environment were defined. Key aspects of a possible spacelab experiment were investigated analytically, experimentally on the bench, and in drop tower facilities. A conceptual design for a spacelab experiment was developed.

  15. Impact Of Melter Internal Design On Off-Gas Flammability

    Energy Technology Data Exchange (ETDEWEB)

    Choi, A. S.; Lee, S. Y.

    2012-05-30

    The purpose of this study was to: (1) identify the more dominant design parameters that can serve as the quantitative measure of how prototypic a given melter is, (2) run the existing DWPF models to simulate the data collected using both DWPF and non-DWPF melter configurations, (3) confirm the validity of the selected design parameters by determining if the agreement between the model predictions and data is reasonably good in light of the design and operating conditions employed in each data set, and (4) run Computational Fluid Dynamics (CFD) simulations to gain new insights into how fluid mixing is affected by the configuration of melter internals and to further apply the new insights to explaining, for example, why the agreement is not good.

  16. Radial artery pseudoaneurysm: A rare complication after a single arterial puncture for blood-gas analysis

    OpenAIRE

    Kajal Nitin Patel; Shruti P Gandhi; Sutariya, Harsh C.

    2016-01-01

    With a reported incidence of 0.048%, radial artery pseudoaneurysm (PA) is a rare but serious complication of arterial cannulation. We report a case of PA developing after a single puncture of the right radial artery for arterial blood-gas analysis diagnosed by Doppler ultrasound in young male patient. The development of PA after puncture of radial artery for continuous blood pressure monitoring and serial blood-gas analysis has been reported in the past; however, to the best of our knowledge,...

  17. Application of PIC microcontrollers in single-sensor dual gas-CO/CH4 detectors

    Science.gov (United States)

    Pietraszek, Stanislaw; Pachole, Aleksander

    2001-08-01

    The main aim of this work is to present an application of PIC16 microcontrollers in single sensor two gas - CO and CH4 detectors, using recently developed by FIS Incorporated, semiconductor sensor SB-95. Microcontroller is used not only for comparison the actual output signal from the sensor with the warning and alarm thresholds, but also provides control and self diagnostic functions. Output logic signals allow user to check the level of gas concentration and detect the improper operation of sensor and electronics circuits.

  18. Applying Flammability Limit Probabilities and the Normoxic Upward Limiting Pressure Concept to NASA STD-6001 Test 1

    Science.gov (United States)

    Olson, Sandra L.; Beeson, Harold; Fernandez-Pello, A. Carlos

    2014-01-01

    Repeated Test 1 extinction tests near the upward flammability limit are expected to follow a Poisson process trend. This Poisson process trend suggests that rather than define a ULOI and MOC (which requires two limits to be determined), it might be better to define a single upward limit as being where 1/e (where e (approx. equal to 2.7183) is the characteristic time of the normalized Poisson process) of the materials burn, or, rounding, where approximately 1/3 of the samples fail the test (and burn). Recognizing that spacecraft atmospheres will not bound the entire oxygen-pressure parameter space, but actually lie along the normoxic atmosphere control band, we can focus the materials flammability testing along this normoxic band. A Normoxic Upward Limiting Pressure (NULP) is defined that determines the minimum safe total pressure for a material within the constant partial pressure control band. Then, increasing this pressure limit by a factor of safety, we can define the material as being safe to use at the NULP + SF (where SF is on the order of 10 kilopascal, based on existing flammability data). It is recommended that the thickest material to be tested with the current Test 1 igniter should be 3 mm thick (1/8 inches) to avoid the problem of differentiating between an ignition limit and a true flammability limit.

  19. Inflammable Gas Mixture Detection with a Single Catalytic Sensor Based on the Electric Field Effect

    Science.gov (United States)

    Tong, Ziyuan; Tong, Min-Ming; Meng, Wen; Li, Meng

    2014-01-01

    This paper introduces a new way to analyze mixtures of inflammable gases with a single catalytic sensor. The analysis technology was based on a new finding that an electric field on the catalytic sensor can change the output sensitivity of the sensor. The analysis of mixed inflammable gases results from processing the output signals obtained by adjusting the electric field parameter of the catalytic sensor. For the signal process, we designed a group of equations based on the heat balance of catalytic sensor expressing the relationship between the output signals and the concentration of gases. With these equations and the outputs of different electric fields, the gas concentration in a mixture could be calculated. In experiments, a mixture of methane, butane and ethane was analyzed by this new method, and the results showed that the concentration of each gas in the mixture could be detected with a single catalytic sensor, and the maximum relative error was less than 5%. PMID:24717635

  20. Experimental and Modeling Study of the Flammability of Fuel Tank Headspace Vapors from Ethanol/Gasoline Fuels; Phase 3: Effects of Winter Gasoline Volatility and Ethanol Content on Blend Flammability; Flammability Limits of Denatured Ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Gardiner, D. P.; Bardon, M. F.; Clark, W.

    2011-07-01

    This study assessed differences in headspace flammability for summertime gasolines and new high-ethanol content fuel blends. The results apply to vehicle fuel tanks and underground storage tanks. Ambient temperature and fuel formulation effects on headspace vapor flammability of ethanol/gasoline blends were evaluated. Depending on the degree of tank filling, fuel type, and ambient temperature, fuel vapors in a tank can be flammable or non-flammable. Pure gasoline vapors in tanks generally are too rich to be flammable unless ambient temperatures are extremely low. High percentages of ethanol blended with gasoline can be less volatile than pure gasoline and can produce flammable headspace vapors at common ambient temperatures. The study supports refinements of fuel ethanol volatility specifications and shows potential consequences of using noncompliant fuels. E85 is flammable at low temperatures; denatured ethanol is flammable at warmer temperatures. If both are stored at the same location, one or both of the tanks' headspace vapors will be flammable over a wide range of ambient temperatures. This is relevant to allowing consumers to splash -blend ethanol and gasoline at fueling stations. Fuels compliant with ASTM volatility specifications are relatively safe, but the E85 samples tested indicate that some ethanol fuels may produce flammable vapors.

  1. Dynamic behavior of gas bubble in single bubble sonoluminescence - vibrator model

    Institute of Scientific and Technical Information of China (English)

    QIAN Menglu; CHENG Qian; GE Caoyan

    2002-01-01

    Single bubble sonoluminescence is a process of energy transformation from soundto light. Therefore the motion equations of near spherical vibration of a gas bubble in anincompressible and viscous liquid can be deduced by Lagrangian Equation with dissipationfunction when the bubble is considered as a vibrator surrounded by liquid. The analyticalsolutions in the bubble expanding, collapsing and rebounding stages can be obtained by solvingthese motion equations when some approximations are adopted. And the dynamic behaviorsof the bubble in these three stages are discussed.

  2. On the temperature dependence of flammability limits of gases.

    Science.gov (United States)

    Kondo, Shigeo; Takizawa, Kenji; Takahashi, Akifumi; Tokuhashi, Kazuaki

    2011-03-15

    Flammability limits of several combustible gases were measured at temperatures from 5 to 100 °C in a 12-l spherical flask basically following ASHRAE method. The measurements were done for methane, propane, isobutane, ethylene, propylene, dimethyl ether, methyl formate, 1,1-difluoroethane, ammonia, and carbon monoxide. As the temperature rises, the lower flammability limits are gradually shifted down and the upper limits are shifted up. Both the limits shift almost linearly to temperature within the range examined. The linear temperature dependence of the lower flammability limits is explained well using a limiting flame temperature concept at the lower concentration limit (LFL)--'White's rule'. The geometric mean of the flammability limits has been found to be relatively constant for many compounds over the temperature range studied (5-100 °C). Based on this fact, the temperature dependence of the upper flammability limit (UFL) can be predicted reasonably using the temperature coefficient calculated for the LFL. However, some compounds such as ethylene and dimethyl ether, in particular, have a more complex temperature dependence.

  3. Plasma gas identification using the single Langmuir probe at the PUPR mirror-cusp

    Energy Technology Data Exchange (ETDEWEB)

    Gaudier, Jorge R; Rivera, Ramon; Colmenares, Franklin; Lleonart, Giovanni; Carrera, Miguel A; Mollina, Omar; Gonzalez, Angel; Leal-Quiros, Edbertho; Prelas, Mark A [University of Missouri-Columbia, Columbia, MO (United States); Plasma Physics Laboratory, Polytechnic University of Puerto Rico, San Juan (Puerto Rico)

    2008-10-15

    Plasma can be produced by ionizing gas particles. Different gases will produce different plasma parameters. Using the single Langmuir probe, the characteristics of argon, nitrogen, hydrogen and residual gas (no gas injected) can be compared. Using a mass spectrometer, we can identify the elements present in the chamber and relate the probe characteristic curve with its respective elements. Each gas has its own characteristic appearance; by looking at the form of the curve it is possible to identify the gas producing the plasma. Plasma parameters may vary due to a number of factors; probe position, microwave power, magnetic confinement, gas and pressure are the factors that we can control. In order to compare gases, operation parameters must remain the same for all tests. Plasma tests were administered on different gases using a microwave power of 198 W to heat the gas and initiate ionization and a coil current of 390 A, while running in mirror mode; that is, the current flowing through two parallel solenoid magnets (coils) used to confine plasma runs in the same direction, making the magnetic field complementary in the direction of the probe. The coils, distance from center to center was fixed at 60 cm. In mirror mode, plasma is confined in a hot electron ring produced between the coils. The ring contains the highest plasma density in the chamber, but the center remains at lower density. The probe was submerged into the plasma 110 cm from the flange, the collector (disc) was 14 cm from the center of the chamber and 18.12 cm from the electron ring. Low power (4% of a 5 kW microwave generator) was used to protect the probes from burning at that close range. The pressure at the chamber was 2.9E-4 Torr. Good readings were taken and analyzed. Measurements with variable microwave power and variable magnetic field strength were also studied to determine whether there is a linear relationship between the machine setup and plasma conditions.

  4. Flammability Control In A Nuclear Waste Vitrification System

    Energy Technology Data Exchange (ETDEWEB)

    Zamecnik, John R.; Choi, Alexander S.; Johnson, Fabienne C.; Miller, Donald H.; Lambert, Daniel P.; Stone, Michael E.; Daniel, William E. Jr.

    2013-07-25

    The Defense Waste Processing Facility at the Savannah River Site processes high-level radioactive waste from the processing of nuclear materials that contains dissolved and precipitated metals and radionuclides. Vitrification of this waste into borosilicate glass for ultimate disposal at a geologic repository involves chemically modifying the waste to make it compatible with the glass melter system. Pretreatment steps include removal of excess aluminum by dissolution and washing, and processing with formic and nitric acids to: 1) adjust the reduction-oxidation (redox) potential in the glass melter to reduce radionuclide volatility and improve melt rate; 2) adjust feed rheology; and 3) reduce by steam stripping the amount of mercury that must be processed in the melter. Elimination of formic acid in pretreatment has been studied to eliminate the production of hydrogen in the pretreatment systems, which requires nuclear grade monitoring equipment. An alternative reductant, glycolic acid, has been studied as a substitute for formic acid. However, in the melter, the potential for greater formation of flammable gases exists with glycolic acid. Melter flammability is difficult to control because flammable mixtures can be formed during surges in offgases that both increase the amount of flammable species and decrease the temperature in the vapor space of the melter. A flammable surge can exceed the 60% of the LFL with no way to mitigate it. Therefore, careful control of the melter feed composition based on scaled melter surge testing is required. The results of engineering scale melter tests with the formic-nitric flowsheet and the use of these data in the melter flammability model are presented.

  5. Effects of surface roughness on hydrogen gas sensing properties of single Pd nanowires.

    Science.gov (United States)

    Lee, Jun Min; Lee, Wooyoung

    2011-03-01

    We report on the effects of surface roughness resulting from an ion milling technique on the hydrogen gas sensing performance of a single Pd nanowire grown by electrodeposition into nanochannels in anodized aluminum oxide templates. A combination of electron beam lithography and a lift-off process was utilized to fabricate four-terminal devices based on individual Pd nanowires. These results are the first demonstration of the effect of ion milling on the response time in a single Pd nanowire used as a hydrogen sensor. The response time of the single Pd nanowire surface-treated by ion milling was 20 times faster than that of a sample without surface treatment. The faster response time was due to the surface roughness effects of the surface treatment, an increase in the surface-to-volume ratio of the ion-milled nanowire.

  6. ISO 14624 Series - Space Systems - Safety and Compatibility of Materials Flammability Assessment of Spacecraft Materials

    Science.gov (United States)

    Hirsch, David B.

    2007-01-01

    A viewgraph presentation on the flammability of spacecraft materials is shown. The topics include: 1) Spacecraft Fire Safety; 2) Materials Flammability Test; 3) Impetus for enhanced materials flammability characterization; 4) Exploration Atmosphere Working Group Recommendations; 5) Approach; and 6) Status of implementation

  7. 14 CFR Appendix M to Part 25 - Fuel Tank System Flammability Reduction Means

    Science.gov (United States)

    2010-01-01

    .... (a) The Fleet Average Flammability Exposure of each fuel tank, as determined in accordance with... failures of the FRM that occur in service that could increase any fuel tank's Fleet Average Flammability... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel Tank System Flammability...

  8. 16 CFR Figure 1 to Part 1610 - Sketch of Flammability Apparatus

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Sketch of Flammability Apparatus 1 Figure 1 to Part 1610 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY OF CLOTHING TEXTILES Pt.1610, Fig. 1 Figure 1 to Part 1610—Sketch...

  9. 46 CFR 30.10-21 - Flammable or inflammable-TB/ALL.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Flammable or inflammable-TB/ALL. 30.10-21 Section 30.10-21 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Definitions § 30.10-21 Flammable or inflammable—TB/ALL. The words flammable and inflammable are interchangeable or...

  10. Dynamics of a single trapped ion immersed in a buffer gas

    CERN Document Server

    Höltkemeier, Bastian; López-Carrera, Henry; Weidemüller, Matthias

    2016-01-01

    We provide a comprehensive theoretical framework for describing the dynamics of a single trapped ion interacting with a neutral buffer gas, thus extending our previous studies on buffer-gas cooling of ions beyond the critical mass ratio [B. H\\"oltkemeier et al., Phys. Rev. Lett. 116, 233003 (2016)]. By transforming the collisional processes into a frame, where the ion's micromotion is assigned to the buffer gas atoms, our model allows one to investigate the influence of non-homogeneous buffer gas configurations as well as higher multipole orders of the radio-frequency trap in great detail. Depending on the neutral-to-ion mass ratio, three regimes of sympathetic cooling are identified which are characterized by the form of the ion's energy distribution in equilibrium. We provide analytic expressions and numerical simulations of the ion's energy distribution, spatial profile and cooling rates for these different regimes. Based on these findings, a method for actively decreasing the ion's energy by reducing the ...

  11. Prediction of Gas Hydrate Formation Conditions in Aqueous Solutions of Single and Mixed Electrolytes

    DEFF Research Database (Denmark)

    Zuo, You-Xiang; Stenby, Erling Halfdan

    1997-01-01

    In this paper, the extended Patel-Teja equation of state was modified to describe non-ideality of the liquid phase containing water and electrolytes accurately. The modified Patel-Teja equation of state (MPT EOS) was utilized to develop a predictive method for gas hydrate equilibria. The new method...... employs the Barkan and Sheinin hydrate model for the description of the hydrate phase, the original Patel-Teja equation of state for the vapor phase fugacities, and the MPT EOS (instead of the activity coefficient model) for the activity of water in the aqueous phase. The new method has succesfully...... predicted the gas hydrate formation conditions in aqueous solutions of single and mixed electrolytes. The agreement between experimental data and predictions was found to be excellent....

  12. Prediction of Gas Hydrate Formation Conditions in Aqueous Solutions of Single and Mixed Electrolytes

    DEFF Research Database (Denmark)

    Zuo, You-Xiang; Stenby, Erling Halfdan

    1997-01-01

    In this paper, the extended Patel-Teja equation of state was modified to describe non-ideality of the liquid phase containing water and electrolytes accurately. The modified Patel-Teja equation of state (MPT EOS) was utilized to develop a predictive method for gas hydrate equilibria. The new method...... employs the Barkan and Sheinin hydrate model for the description of the hydrate phase, the original Patel-Teja equation of state for the vapor phase fugacities, and the MPT EOS (instead of the activity coefficient model) for the activity of water in the aqueous phase. The new method has succesfully...... predicted the gas hydrate formation conditions in aqueous solutions of single and mixed electrolytes. The agreement between experimental data and predictions was found to be excellent....

  13. Pulse gas alignment and AFM manipulation of single-wall carbon nanotube

    Institute of Scientific and Technical Information of China (English)

    TIAN XiaoJun; WANG YueChao; XI Ning; DONG ZaiLi; TUNG Steve

    2008-01-01

    In the fabrication process of nanoelectronic device arrays based on single-wall carbon nanotube (SWCNT), oriented alignment of SWCNTs and property modification of metallic SWCNTs in the array are the key problems to be solved. Pulse gas alignment with substrate downward tilt is proposed to realize the controllable alignment of SWCNTs. Experimental results demonstrate that 84% SWCNTs are aligned in -15°- 15° angular to the pulse gas direction. A modified nanomanipulation technology based on atomic force microscope (AFM) is utilized to perform various kinds of SWCNT manipulation, such as SWCNT separation from the "Y" CNT, catalyst removal from the SWCNT end, continual nano buckles fabrication on SWCNT and even stretching to break, which provides a feasible way to modify the size, shape and the electrical property of SWCNTs.

  14. Selective and uniform growth of single-wall carbon nanotubes (SWCNTs) for gas sensing application

    Science.gov (United States)

    Alvi, M. A.; Al-Ghamdi, A. A.; Khan, Shamshad A.

    2017-03-01

    In the present work, we have synthesized uniformly distributed single-wall carbon nanotube (SWCNT) networks with a selective diameter suitable for gas sensing device. The SWCNT networks have been synthesized on 2-nm-thick iron (Fe) catalyst-coated silicon (Si) substrates by Plasma-Enhanced Chemical Vapor Deposition (PECVD). The as-grown SWCNTs were characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy techniques. Using SWCNT network, the sensitivity of ammonia (NH3) gases/vapors was recognized by their surface adsorption and desorption responses. The response curve was observed from the SWCNT network, which is due to a change in the resistance upon exposure to NH3 gas.

  15. Theoretical evaluation of the efficiency of gas single-stage reciprocating compressor medium pressure units

    Science.gov (United States)

    Busarov, S. S.; Vasil'ev, V. K.; Busarov, I. S.; Titov, D. S.; Panin, Ju. N.

    2017-08-01

    Developed earlier and tested in such working fluid as air, the technology of calculating the operating processes of slow-speed long-stroke reciprocating stages let the authors to obtain successful results concerning compression of gases to medium pressures in one stage. In this connection, the question of the efficiency of the application of slow-speed long-stroke stages in various fields of technology and the national economy, where the working fluid is other gas or gas mixture, is topical. The article presents the results of the efficiency evaluation of single-stage compressor units on the basis of such stages for cases when ammonia, hydrogen, helium or propane-butane mixture is used as the working fluid.

  16. Simulating the signature produced by a single airgun under real gas conditions

    Institute of Scientific and Technical Information of China (English)

    Wang Feng-Fan; Liu Huai-Shan

    2014-01-01

    Models that simulate the signature of single airguns form the basis for modeling the signals of airgun arrays. Most of the existing models assume that the air inside the produced bubble is ideal gas, which may lead to errors because of the high operating pressure of the airguns. In this study, we propose a model that precisely simulates the signals of single airguns by applying the Van der Waals equation based on the Ziolkowski algorithm. We also consider a thermodynamically open quasistatic system, the heat transition between water and gas, the throttling effect of the port and the bubble rise, and the effect of the sea surface. Modeling experiments show that (1) the energy of the source increases and the signal-to-noise ratio of the signature wavelet decreases with increasing seawater temperature, (2) the reflection coefficient of the sea surface under the actual state and depth of the source affects the notch caused by the surface reflection, (3) the computed signature with the proposed model is very close to the actual data, and (4) the proposed model accurately simulates the signature of single airguns.

  17. Powerful greenhouse gas nitrous oxide adsorption onto intrinsic and Pd doped Single walled carbon nanotube

    Science.gov (United States)

    Yoosefian, Mehdi

    2017-01-01

    Density functional studies on the adsorption behavior of nitrous oxide (N2O) onto intrinsic carbon nanotube (CNT) and Pd-doped (5,5) single-walled carbon nanotube (Pd-CNT) have been reported. Introduction of Pd dopant facilitates in adsorption of N2O on the otherwise inert nanotube as observed from the adsorption energies and global reactivity descriptor values. Among three adsorption features of N2O onto CNT, the horizontal adsorption with Eads = -0.16 eV exhibits higher adsorption energy. On the other hand the Pd-CNT exhibit strong affinity toward gas molecule and would cause a huge increase in N2O adsorption energies. Chemical and electronic properties of CNT and Pd-CNT in the absence and presence of N2O were investigated. Adsorption of N2O gas molecule would affect the electronic conductance of Pd-CNT that can serve as a signal of gas sensors and the increased energy gaps demonstrate the formation of more stable systems. The atoms in molecules (AIM) theory and the natural bond orbital (NBO) calculations were performed to get more details about the nature and charge transfers in intermolecular interactions within adsorption process. As a final point, the density of states (DOSs) calculations was achieved to confirm previous results. According to our results, intrinsic CNT cannot act as a suitable adsorbent while Pd-CNT can be introduced as novel detectable complex for designing high sensitive, fast response and high efficient carbon nanotube based gas sensor to detect N2O gas as an air pollutant. Our results could provide helpful information for the design and fabrication of the N2O sensors.

  18. The flammability limits of lean fuel-air mixtures: thermochemical and kinetic criteria for explosion hazards.

    Science.gov (United States)

    Burgess, D; Hertzberg, M

    1975-01-01

    The present state of knowledge is reviewed concisely in terms of the experimental methods used, the effect of apparatus size, accuracy of data, methods of data presentation, and the sensitivity of the limits to initial temperature and pressure. The heat of combustion per mole of gas mixture at the lean limit is a reliable thermochemical criterion for the flammability of organic fuels with comparable reactivities. The limit calorific value for the heavy paraffins is 11.5 +/- 0.1 kcal mole -1. However, kinetic effects strongly influence this value. Highly reactive fuels (hydrogen, acetylene) require lower energy contents, whereas less reactive fuels (ammonia) require higher values. Hydrogen-starved fuels (carbon monoxide, cyanogen) show marked anomalies and are sensitive to impurities that can provide H-atom chain carriers. These kinetic effects are reflected in the experimentally measurable burning velocity of the fuel. This parameter is a key ingredient in the theory of flammable limits, which is briefly sketched. Five competing processes dissipate power from the combustion wave and quench it at some characteristic limit velocity. The prevalent consensus that the limits are controlled by natural convection is clearly demonstrated, and the complex interplay of kinetics and thermochemistry follows logically therefrom.

  19. Effects of Radiative and Diffusive Transport Processes on Premixed Flames near Flammability Limits

    Science.gov (United States)

    Abbud-Madrid, Angel; Ronney, Paul D.

    1991-01-01

    A study of the mechanisms of flammability limits and the dynamics of flame extinguishment in premixed gas flames is described, a novel feature of which is the use of diluent gases having a wide range of radiative and diffusive transport properties. This feature enables an assessment of the importance of volumetric heat losses and Lewis number effects on these mechanisms. Additionally, effects of flame dynamics and flame front curvature are studied by employing spherically expanding flames obtained in a microgravity environment whereby natural convection is eliminated. New diagnostics include chamber pressure measurements and the first reported species concentration measurements in a microgravity combustion experiment. The limit mechanisms and extinguishment phenomena are found to be strongly influenced by the combined effects of radiant heat loss, Lewis number and flame curvature. Two new and as yet not well understood phenomena are reported: 'double flames' in rich H2-O2-CO2 mixtures and an 'inverse flammability region' in rich C3H8-O2-CO2 mixtures.

  20. Evaluation of lower flammability limits of fuel-air-diluent mixtures using calculated adiabatic flame temperatures.

    Science.gov (United States)

    Vidal, M; Wong, W; Rogers, W J; Mannan, M S

    2006-03-17

    The lower flammability limit (LFL) of a fuel is the minimum composition in air over which a flame can propagate. Calculated adiabatic flame temperatures (CAFT) are a powerful tool to estimate the LFL of gas mixtures. Different CAFT values are used for the estimation of LFL. SuperChems is used by industry to perform flammability calculations under different initial conditions which depends on the selection of a threshold temperature. In this work, the CAFT at the LFL is suggested for mixtures of fuel-air and fuel-air-diluents. These CAFT can be used as the threshold values in SuperChems to calculate the LFL. This paper discusses an approach to evaluate the LFL in the presence of diluents such as N2 and CO2 by an algebraic method and by the application of SuperChems using CAFT as the basis of the calculations. The CAFT for different paraffinic and unsaturated hydrocarbons are presented as well as an average value per family of chemicals.

  1. Estimation of the lower flammability limit of organic compounds as a function of temperature.

    Science.gov (United States)

    Rowley, J R; Rowley, R L; Wilding, W V

    2011-02-15

    A new method of estimating the lower flammability limit (LFL) of general organic compounds is presented. The LFL is predicted at 298 K for gases and the lower temperature limit for solids and liquids from structural contributions and the ideal gas heat of formation of the fuel. The average absolute deviation from more than 500 experimental data points is 10.7%. In a previous study, the widely used modified Burgess-Wheeler law was shown to underestimate the effect of temperature on the lower flammability limit when determined in a large-diameter vessel. An improved version of the modified Burgess-Wheeler law is presented that represents the temperature dependence of LFL data determined in large-diameter vessels more accurately. When the LFL is estimated at increased temperatures using a combination of this model and the proposed structural-contribution method, an average absolute deviation of 3.3% is returned when compared with 65 data points for 17 organic compounds determined in an ASHRAE-style apparatus.

  2. Effect of Meltable Triazine-DOPO Additive on Rheological, Mechanical, and Flammability Properties of PA6

    Directory of Open Access Journals (Sweden)

    Irina Butnaru

    2015-08-01

    Full Text Available Through a straightforward approach, a new meltable, halogen-free, nitrogen-phosphorus-based flame retardant (FR, 6-(2-(4,6-diamino-1,3,5-triazin-2-ylethyl dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DTE-DOPO was synthesized and incorporated in polyamide 6 (PA6. It was proved that a very low phosphorus content of 1.46 wt% for DTE-DOPO additive improved the flame retardancy of PA6, leading to a non-flammable material. The performance of the new additive was compared to that of the commercially-available Exolit® OP 1230. The PA6 formulations were evaluated by measuring the rheological, mechanical, and flammability behavior. Using compounding by melt extrusion, 17 wt% additives was introduced into PA6 matrix and the corresponding formulations were characterized. The results evidenced a higher homogeneity of DTE-DOPO with PA6, a high thermal stability with a catalyzing decomposition effect on PA6 caused by the presence of the new developed FR, enhanced elasticity for the PA6/DTE-DOPO formulation and a V0 rating for both formulations. Thermal and fire analysis indicated a primary gas-phase activity, combined with a complete suppression of the self-sustained burning for the PA6/DTE-DOPO formulation.

  3. Bayesian Estimation of Fugitive Methane Point Source Emission Rates from a SingleDownwind High-Frequency Gas Sensor

    Science.gov (United States)

    Bayesian Estimation of Fugitive Methane Point Source Emission Rates from a Single Downwind High-Frequency Gas Sensor With the tremendous advances in onshore oil and gas exploration and production (E&P) capability comes the realization that new tools are needed to support env...

  4. The effects of perturbations on the flammability limits

    Science.gov (United States)

    T'Ien, J. S.

    1973-01-01

    Based on the mechanism of heat losses, the known effects of external disturbances (pressure waves or turbulences) on the flammability limits are explained. This includes the sensitivity of near-limit flames to perturbations and the flame quenching by disturbances. The significance of the unstable solution as the criterion for dynamic extinction is stressed.

  5. Spruce beetle-induced changes to Engelmann spruce foliage flammability

    Science.gov (United States)

    Wesley G. Page; Michael J. Jenkins; Justin B. Runyon

    2014-01-01

    Intermountain Engelmann spruce (Picea engelmannii Parry ex Engelm) stands affected by the spruce beetle (Dendroctonus rufipennis Kirby) represent a unique and growing fuel complex. In this study, we quantified and compared the changes in moisture content, chemistry, and flammability of foliage from trees in three crown condition classes: unattacked (green [G]),...

  6. Site-resolved imaging of single atoms with a Faraday quantum gas microscope

    CERN Document Server

    Yamamoto, Ryuta; Kato, Kohei; Kuno, Takuma; Sakura, Yuto; Takahashi, Yoshiro

    2016-01-01

    We successfully demonstrate a quantum gas microscopy using the Faraday effect which has an inherently non-destructive nature. The observed Faraday rotation angle reaches 3.0(2) degrees for a single atom. We reveal the non-destructive feature of this Faraday imaging method by comparing the detuning dependence of the Faraday signal strength with that of the photon scattering rate. We determine the atom distribution with deconvolution analysis. We also demonstrate the absorption and the dark field Faraday imaging, and reveal the different shapes of the point spread functions for these methods, which are fully explained by theoretical analysis. Our result is an important first step towards an ultimate quantum non-demolition site-resolved imaging and furthermore opens up the possibilities for quantum feedback control of a quantum many-body system with a single-site resolution.

  7. Gas Detection for Experiments

    CERN Document Server

    Hay, D

    2001-01-01

    Flammable gases are often used in detectors for physics experiments. The storage, distribution and manipulation of such flammable gases present several safety hazards. As most flammable gases cannot be detected by human senses, specific well-placed gas detection systems must be installed. Following a request from the user group and in collaboration with CERN safety officers, risk analyses are performed. An external contractor, who needs to receive detailed user requirements from CERN, performs the installations. The contract is passed on a guaranteed results basis. Co-ordination between all the CERN groups and verification of the technical installation is done by ST/AA/AS. This paper describes and focuses on the structured methodology applied to implement such installations based on goal directed project management techniques (GDPM). This useful supervision tool suited to small to medium sized projects facilitates the task of co-ordinating numerous activities to achieve a completely functional system.

  8. 16 CFR 1609.1 - Text of the Flammable Fabrics Act of 1953, as amended in 1954.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Text of the Flammable Fabrics Act of 1953... FLAMMABLE FABRICS ACT REGULATIONS TEXT OF THE FLAMMABLE FABRICS ACT OF 1953, AS AMENDED IN 1954, PRIOR TO 1967 AMENDMENT AND REVISION § 1609.1 Text of the Flammable Fabrics Act of 1953, as amended in 1954....

  9. Single-stage EHD thruster response to several simulation conditions in nitrogen gas

    Science.gov (United States)

    Granados, Victor H.; Pinheiro, Mario J.; Sá, Paulo A.

    2017-09-01

    We use a numerical model to investigate the influence of pressure from 0.5 Torr (66.7 Pa) to 100 Torr (13.3 kPa) and temperature (190-400 K) on the performance (thrust, fluid velocity, and thrust-to-power-ratio) of a single stage electrohydrodynamic thruster made of a rod anode and funnel-like cathode geometry, using nitrogen as the working gas. The model includes the following nitrogen species: N, N+, N2, N2+ , and N4+ . Additional factors are investigated: (i) the ballast resistance, (ii) the secondary electron emission from the cathode (in the range of 10-5 -10°), and (iii) the influence of the gap between electrodes on the discharge. As expected, higher pressures increase the net thrust, thrust efficiency, and peak gas velocity; however, with increasing temperatures, the trend reverses. We notice that gas flow velocity diminishes for the increasing values of the secondary emission coefficient, and it is possible to identify two working regimes presenting different behaviors: in the first region, for values of the secondary electron emission coefficient between 10-5 and 10-2 , thrust was not affected, and in the second region, between 10-2 and 1, a clear decrease in thrust is observed, accompanied by an increase in the discharge current, an undesired effect for the purpose of thrust production.

  10. Predictive Modelling of Concentration of Dispersed Natural Gas in a Single Room

    Directory of Open Access Journals (Sweden)

    Abdulfatai JIMOH

    2009-07-01

    Full Text Available This paper aimed at developing a mathematical model equation to predict the concentration of natural gas in a single room. The model equation was developed by using theoretical method of predictive modelling. The model equation developed is as given in equation 28. The validity of the developed expression was tested through the simulation of experimental results using computer software called MathCAD Professional. Both experimental and simulated results were found to be in close agreement. The statistical analysis carried out through the correlation coefficients for the results of experiment 1, 2, 3 and 4 were found to be 0.9986, 1.0000, 0.9981 and 0.9999 respectively, which imply reasonable close fittings between the experimental and simulated concentrations of dispersed natural gas within the room. Thus, the model equation developed can be considered a good representation of the phenomena that occurred when there is a leakage or accidental release of such gas within the room.

  11. Research into comprehensive gas extraction technology of single coal seams with low permeability in the Jiaozuo coal mining area

    Institute of Scientific and Technical Information of China (English)

    Fu Jiangwei; Fu Xuehai; Hu Xiao; Chen Li; Ou Jianchun

    2011-01-01

    For a low permeability single coal seam prone to gas outbursts,pre-drainage of gas is difficult and inefficient,seriously restricting the safety and efficiency of production.Radical measures of increasing gas extraction efficiency are pressure relief and infrared antireflection.We have analyzed the effect of mining conditions and the regularity of mine pressure distribution in front of the working face of a major coal mine of the Jiaozuo Industrial (Group) Co.as our test area,studied the width of the depressurization zone in slice mining and analyzed gas efficiency and fast drainage in the advanced stress relaxation zone.On that basis,we further investigated and practiced the exploitation technology of shallow drilling,fan drilling and grid shape drilling at the working face.Practice and our results show that the stress relaxation zone is the ideal region for quick and efficient extraction of gas.By means of an integrated extraction technology,the amount of gas emitted into the zone was greatly reduced,while the risk of dangerous outbursts of coal and gas was lowered markedly.This exploration provides a new way to control for gas in working faces of coal mines with low permeability and risk of gas outbursts of single coal seams in the Jiaozuo mining area.

  12. Electron attachment to DNA single strands: gas phase and aqueous solution

    Science.gov (United States)

    Gu, Jiande; Xie, Yaoming; Schaefer, Henry F.

    2007-01-01

    The 2′-deoxyguanosine-3′,5′-diphosphate, 2′-deoxyadenosine-3′,5′-diphosphate, 2′-deoxycytidine-3′,5′-diphosphate and 2′-deoxythymidine-3′,5′-diphosphate systems are the smallest units of a DNA single strand. Exploring these comprehensive subunits with reliable density functional methods enables one to approach reasonable predictions of the properties of DNA single strands. With these models, DNA single strands are found to have a strong tendency to capture low-energy electrons. The vertical attachment energies (VEAs) predicted for 3′,5′-dTDP (0.17 eV) and 3′,5′-dGDP (0.14 eV) indicate that both the thymine-rich and the guanine-rich DNA single strands have the ability to capture electrons. The adiabatic electron affinities (AEAs) of the nucleotides considered here range from 0.22 to 0.52 eV and follow the order 3′,5′-dTDP > 3′,5′-dCDP > 3′,5′-dGDP > 3′,5′-dADP. A substantial increase in the AEA is observed compared to that of the corresponding nucleic acid bases and the corresponding nucleosides. Furthermore, aqueous solution simulations dramatically increase the electron attracting properties of the DNA single strands. The present investigation illustrates that in the gas phase, the excess electron is situated both on the nucleobase and on the phosphate moiety for DNA single strands. However, the distribution of the extra negative charge is uneven. The attached electron favors the base moiety for the pyrimidine, while it prefers the 3′-phosphate subunit for the purine DNA single strands. In contrast, the attached electron is tightly bound to the base fragment for the cytidine, thymidine and adenosine nucleotides, while it almost exclusively resides in the vicinity of the 3′-phosphate group for the guanosine nucleotides due to the solvent effects. The comparatively low vertical detachment energies (VDEs) predicted for 3′,5′-dADP− (0.26 eV) and 3′,5′-dGDP− (0.32 eV) indicate that electron detachment

  13. 16 CFR Figure 5 to Part 1610 - An Example of a Typical Gas Shield

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false An Example of a Typical Gas Shield 5 Figure 5 to Part 1610 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY OF CLOTHING TEXTILES Pt.1610, Fig. 5 Figure 5 to Part...

  14. Highly efficient single-layer gas diffusion layers for the proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Hung, T.F.; Bai, S.H.; Lai, Y.J.; Chen-Yang, Y.W. [Department of Chemistry and Center for Nanotechnology, Chung Yuan Christian University, Chung-Li 32023 (China); Huang, J. [Yeu Ming Tai Chemical Industrial Co., Ltd., Taichung 40768 (China); Chuang, H.J. [Materials and Electro-Optics Research Division, Electric Energy Section, Chung Shan Institute of Science and Technology, Lung-Tan 32544 (China)

    2008-09-15

    In the present study, a series of highly efficient single-layer gas diffusion layers (SL-GDLs) was successfully prepared by the addition of a vapor grown carbon nanofiber (VGCF) in the carbon black/poly(tetrafluoroethylene) composite-based SL-GDL through a simple and inexpensive process. The scanning electron micrographs of the as-prepared VGCF-containing SL-GDLs (SL-GDL-CFs) showed that the GDLs had a microporous layer (MPL)-like structure, while the wire-like VGCFs were well dispersed and crossed among the carbon black particles in the SL-GDL matrix. Utilization of the SL-GDL-CFs for MEA fabrication was also done by direct coating with the catalyst layer. Due to the presence of VGCFs, the properties of the SL-GDL-CFs, including electronic resistivity, mechanical characteristic, gas permeability, and water repellency, varied with the VGCF content, with the overall effect beneficial to the performance of the proton exchange membrane fuel cell (PEMFC). The best performances obtained from the PEMFC with VGCFs at 15 wt.% was approximately 63% higher than those without VGCFs, and about 85% as efficient as ELAT GDL, a commercial dual-layer GDL, for both the H{sub 2}/O{sub 2} and H{sub 2}/air systems. (author)

  15. Single-step gas phase synthesis of stable iron aluminide nanoparticles with soft magnetic properties

    Directory of Open Access Journals (Sweden)

    Jerome Vernieres

    2014-11-01

    Full Text Available Soft magnetic alloys at the nanoscale level have long generated a vivid interest as candidate materials for technological and biomedical purposes. Consequently, controlling the structure of bimetallic nanoparticles in order to optimize their magnetic properties, such as high magnetization and low coercivity, can significantly boost their potential for related applications. However, traditional synthesis methods stumble upon the long standing challenge of developing true nanoalloys with effective control over morphology and stability against oxidation. Herein, we report on a single-step approach to the gas phase synthesis of soft magnetic bimetallic iron aluminide nanoparticles, using a versatile co-sputter inert gas condensation technique. This method allowed for precise morphological control of the particles; they consisted of an alloy iron aluminide crystalline core (DO3 phase and an alumina shell, which reduced inter-particle interactions and also prevented further oxidation and segregation of the bimetallic core. Remarkably, the as-deposited alloy nanoparticles show interesting soft magnetic properties, in that they combine a high saturation magnetization (170 emu/g and low coercivity (less than 20 Oe at room temperature. Additional functionality is tenable by modifying the surface of the particles with a polymer, to ensure their good colloidal dispersion in aqueous environments.

  16. ZnO nanoflowers with single crystal structure towards enhanced gas sensing and photocatalysis.

    Science.gov (United States)

    Zhang, Sha; Chen, Hsueh-Shih; Matras-Postolek, Katarzyna; Yang, Ping

    2015-11-11

    In this paper, ZnO nanoflowers (NFs) were fabricated by thermal decomposition in an organic solvent and their application in gas sensors and photocatalysis was investigated. These single crystal ZnO NFs, which were observed for the first time, with an average size of ∼60 nm and were grown along the {100} facet. It was suggested that oleylamine used in the synthesis inhibited the growth and agglomeration of ZnO through the coordination of the oleylamine N atoms. The NFs exhibited excellent selectivity to acetone with a concentration of 25 ppm at 300 °C because they had a high specific surface area that provided more active sites and the surface adsorbed oxygen species for interaction with acetone. In addition, the ZnO NFs showed enhanced gas sensing response which was also ascribed to abundant oxygen vacancies at the junctions between petals of the NFs. Furthermore, ZnO-reduced graphene oxide (RGO) composites were fabricated by loading the ZnO NFs on the surface of the stratiform RGO sheet. In the photodegradation of rhodamine B tests, the composite revealed an enhanced photocatalytic performance compared with ZnO NFs under UV light irradiation.

  17. Enhanced nitrogen removal in single-chamber microbial fuel cells with increased gas diffusion areas

    KAUST Repository

    Yan, Hengjing

    2012-11-23

    Single-chamber microbial fuel cells (MFCs) with nitrifiers pre-enriched at the air cathodes have previously been demonstrated as a passive strategy for integrating nitrogen removal into current-generating bioelectrochemical systems. To further define system design parameters for this strategy, we investigated in this study the effects of oxygen diffusion area and COD/N ratio in continuous-flow reactors. Doubling the gas diffusion area by adding an additional air cathode or a diffusion cloth significantly increased the ammonia and COD removal rates (by up to 115% and 39%), ammonia removal efficiency (by up to 134%), the cell voltage and cathode potentials, and the power densities (by a factor of approximately 2). When the COD/N ratio was lowered from 13 to 3, we found up to 244% higher ammonia removal rate but at least 19% lower ammonia removal efficiency. An increase of COD removal rate by up to 27% was also found when the COD/N ratio was lowered from 11 to 3. The Coulombic efficiency was not affected by the additional air cathode, but decreased by an average of 11% with the addition of a diffusion cloth. Ammonia removal by assimilation was also estimated to understand the ammonia removal mechanism in these systems. These results showed that the doubling of gas diffusion area enhanced N and COD removal rates without compromising electrochemical performance. © 2012 Wiley Periodicals, Inc.

  18. Flammability Properties of Composites of Wood Fiber and Recycled Plastic

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Flammability properties of composites of wood fiber and recycled plastic were evaluated by the cone calorimeter and oxygen index chamber. Results were shown as follows: 1) Wood-PVC composite showed worse thermal stability on time to ignition (TTI) and mean heat release rate (MHRR), but better performance on heat release rate (HRR) and mean efficient heat of combustion (MEHC); wood-PP composite had better thermal stability properties, but was worse on other fire performance; 2) Compared with wood-PVC composi...

  19. Flammability Limits of Gases Under Low Gravity Conditions

    Science.gov (United States)

    Strehlow, R. A.

    1985-01-01

    The purpose of this combustion science investigation is to determine the effect of zero, fractional, and super gravity on the flammability limits of a premixed methane air flame in a standard 51 mm diameter flammability tube and to determine, if possible, the fluid flow associated with flame passage under zero-g conditions and the density (and hence, temperature) profiles associated with the flame under conditions of incipient extinction. This is accomplished by constructing an appropriate apparatus for placement in NASA's Lewis Research Center Lear Jet facility and flying the prescribed g-trajectories while the experiment is being performed. Data is recorded photographically using the visible light of the flame. The data acquired is: (1) the shape and propagation velocity of the flame under various g-conditions for methane compositions that are inside the flammable limits, and (2) the effect of gravity on the limits. Real time accelerometer readings for the three orthogonal directions are displayed in full view of the cameras and the framing rate of the cameras is used to measure velocities.

  20. Influence of gas flow on thermal field and stress during growth of sapphire single crystal using Kyropoulos method

    Institute of Scientific and Technical Information of China (English)

    LI Jinquan; SU Xiaoping; NA Mujilatu; YANG Hai; LI Jianmin; YU Yunqi; MI Jianjun

    2006-01-01

    The professional modeling software package CrysVUn was employed to study the process of a large sapphire single crystal growth using Kyropoulos method.The influence of gas pressure on thermal field, solid-liquid interface shape, gas velocity field and von Mises stress were studied for the first time.It is found that the root of the seed melt when gas pressure equals to one atmosphere or more than one atmosphere, especially during the seeding period, this result is consistent with the experimental observation, and this paper presents three ways to solve this problem.The temperature gradient and stress decreases significantly as the gas pressure increases.The convexity of the solid-liquid interface slightly increases when the gas pressure increases.Numerical analysis was used to optimize the hot zone design.

  1. A Gas Target Internal to the LHC for the Study of pp Single-Spin Asymmetries and Heavy Ion Collisions

    Directory of Open Access Journals (Sweden)

    Colin Barschel

    2015-01-01

    Full Text Available We discuss the application of an open storage cell as gas target for a proposed LHC fixed-target experiment AFTER@LHC. The target provides a high areal density at minimum gas input, which may be polarized 1H, 2H, or 3He gas or heavy inert gases in a wide mass range. For the study of single-spin asymmetries in pp interaction, luminosities of nearly 1033/cm2 s can be produced with existing techniques.

  2. Conductive Polymer Synthesis with Single-Crystallinity via a Novel Plasma Polymerization Technique for Gas Sensor Applications

    Directory of Open Access Journals (Sweden)

    Choon-Sang Park

    2016-09-01

    Full Text Available This study proposes a new nanostructured conductive polymer synthesis method that can grow the single-crystalline high-density plasma-polymerized nanoparticle structures by enhancing the sufficient nucleation and fragmentation of the pyrrole monomer using a novel atmospheric pressure plasma jet (APPJ technique. Transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, X-ray photoelectron spectroscopy (XPS, and field emission scanning electron microscopy (FE-SEM results show that the plasma-polymerized pyrrole (pPPy nanoparticles have a fast deposition rate of 0.93 µm·min−1 under a room-temperature process and have single-crystalline characteristics with porous properties. In addition, the single-crystalline high-density pPPy nanoparticle structures were successfully synthesized on the glass, plastic, and interdigitated gas sensor electrode substrates using a novel plasma polymerization technique at room temperature. To check the suitability of the active layer for the fabrication of electrochemical toxic gas sensors, the resistance variations of the pPPy nanoparticles grown on the interdigitated gas sensor electrodes were examined by doping with iodine. As a result, the proposed APPJ device could obtain the high-density and ultra-fast single-crystalline pPPy thin films for various gas sensor applications. This work will contribute to the design of highly sensitive gas sensors adopting the novel plasma-polymerized conductive polymer as new active layer.

  3. Growth of Cd0.96Zn0.04Te single crystals by vapor phase gas transport method

    Directory of Open Access Journals (Sweden)

    S. H. Tabatabai Yazdi

    2006-03-01

    Full Text Available   Cd0.96Zn0.04Te crystals were grown using vapor phase gas transport method (VPGT. The results show that dendritic crystals with grain size up to 3.5 mm can be grown with this technique. X-ray diffraction and Laue back-reflection patterns show that dendritic crystals are single-phase, whose single crystal grains are randomly oriented with respect to the gas-transport axis. Electrical measurements, carried out using Van der Pauw method, show that the as-grown crystals have resistivity of about 104 Ω cm and n-type conductivity.

  4. Litter flammability of French Mediterranean vegetation types : a cross-substratum analysis

    OpenAIRE

    Curt, T.; Schaffhauser, A.; Borgniet, L.; Esteve, R.; Ganteaume, A.; Jappiot, M.; Lampin-Maillet, C.; Martin, W.; N'Diaye, A

    2010-01-01

    International audience; Assessing the flammability of litters in fire-prone ecosystems of major importance to quantify the wildland fire hazard. We compared undisturbed litter samples typical of French ecosystems on the two main types of substratum, i.e. acidic versus limestone, to investigate to which extent their characteristics and flammability may differ. We measured in the laboratory several flammability parameters on oven-dried samples that mimic the high fire hazard level in summer. On...

  5. Flammability Testing of Fabrics Treated with Oil-Based Shear Thickening Fluids

    Science.gov (United States)

    2014-05-01

    thickening fluid (STF) are evaluated under flammability testing. The tested fabrics include a woven cotton-nylon blend, a woven Kevlar textile, and a...hybrid ultrahigh molecular weight polyethylene (UHMWPE) – Kevlar felt. The oil-based STF is a colloid of silica nanoparticles in a paraffin oil. Test...enhanced flammability resistance. 15. SUBJECT TERMS shear thickening fluid, Kevlar , flammability 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  6. A quantum gas microscope for detecting single atoms in a Hubbard-regime optical lattice.

    Science.gov (United States)

    Bakr, Waseem S; Gillen, Jonathon I; Peng, Amy; Fölling, Simon; Greiner, Markus

    2009-11-05

    Recent years have seen tremendous progress in creating complex atomic many-body quantum systems. One approach is to use macroscopic, effectively thermodynamic ensembles of ultracold atoms to create quantum gases and strongly correlated states of matter, and to analyse the bulk properties of the ensemble. For example, bosonic and fermionic atoms in a Hubbard-regime optical lattice can be used for quantum simulations of solid-state models. The opposite approach is to build up microscopic quantum systems atom-by-atom, with complete control over all degrees of freedom. The atoms or ions act as qubits and allow the realization of quantum gates, with the goal of creating highly controllable quantum information systems. Until now, the macroscopic and microscopic strategies have been fairly disconnected. Here we present a quantum gas 'microscope' that bridges the two approaches, realizing a system in which atoms of a macroscopic ensemble are detected individually and a complete set of degrees of freedom for each of them is determined through preparation and measurement. By implementing a high-resolution optical imaging system, single atoms are detected with near-unity fidelity on individual sites of a Hubbard-regime optical lattice. The lattice itself is generated by projecting a holographic mask through the imaging system. It has an arbitrary geometry, chosen to support both strong tunnel coupling between lattice sites and strong on-site confinement. Our approach can be used to directly detect strongly correlated states of matter; in the context of condensed matter simulation, this corresponds to the detection of individual electrons in the simulated crystal. Also, the quantum gas microscope may enable addressing and read-out of large-scale quantum information systems based on ultracold atoms.

  7. Preventing Buoyant Displacement Gas Release Events in Hanford Double-Shell Waste Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Perry A.; Stewart, Charles W.

    2001-01-01

    This report summarizes the predictive methods used to ensure that waste transfer operations in Hanford waste tanks do not create waste configurations that lead to unsafe gas release events. The gas release behavior of the waste in existing double-shell tanks has been well characterized, and the flammable gas safety issues associated with safe storage of waste in the current configuration are being formally resolved. However, waste is also being transferred between double-shell tanks and from single-shell tanks into double-shell tanks by saltwell pumping and sluicing that create new wastes and waste configurations that have not been studied as well. Additionally, planning is underway for various waste transfer scenarios to support waste feed delivery to the proposed vitrification plant. It is critical that such waste transfers do not create waste conditions with the potential for dangerous gas release events.

  8. Electrochemistry of single nanobubbles. Estimating the critical size of bubble-forming nuclei for gas-evolving electrode reactions.

    Science.gov (United States)

    German, Sean R; Edwards, Martin A; Chen, Qianjin; Liu, Yuwen; Luo, Long; White, Henry S

    2016-12-12

    In this article, we address the fundamental question: "What is the critical size of a single cluster of gas molecules that grows and becomes a stable (or continuously growing) gas bubble during gas evolving reactions?" Electrochemical reactions that produce dissolved gas molecules are ubiquitous in electrochemical technologies, e.g., water electrolysis, photoelectrochemistry, chlorine production, corrosion, and often lead to the formation of gaseous bubbles. Herein, we demonstrate that electrochemical measurements of the dissolved gas concentration, at the instant prior to nucleation of an individual nanobubble of H2, N2, or O2 at a Pt nanodisk electrode, can be analyzed using classical thermodynamic relationships (Henry's law and the Young-Laplace equation - including non-ideal corrections) to provide an estimate of the size of the gas bubble nucleus that grows into a stable bubble. We further demonstrate that this critical nucleus size is independent of the radius of the Pt nanodisk employed (gas. For example, the measured critical surface concentration of H2 of ∼0.23 M at the instant of bubble formation corresponds to a critical H2 nucleus that has a radius of ∼3.6 nm, an internal pressure of ∼350 atm, and contains ∼1700 H2 molecules. The data are consistent with stochastic fluctuations in the density of dissolved gas, at or near the Pt/solution interface, controlling the rate of bubble nucleation. We discuss the growth of the nucleus as a diffusion-limited process and how that process is affected by proximity to an electrode producing ∼10(11) gas molecules per second. Our study demonstrates the advantages of studying a single-entity, i.e., an individual nanobubble, in understanding and quantifying complex physicochemical phenomena.

  9. Retained gas sampler system acceptance test report

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, N.S., Westinghouse Hanford

    1996-07-18

    Acceptance test results for the Retained Gas Sampler System (RGSS) obtained in the 306E laboratory are reported. The RGSS will be utilized to retrieve and analyze samples from the Hanford flammable gas watch-list tanks to determine the quantity and chemistry of gases confined within the waste.

  10. Program plan for evaluation and remediation of the generation and release of flammable gases in Hanford Site waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, G.D. (comp.)

    1991-08-01

    This program plan describes the activities being conducted for the resolution of the flammable gas problem that is associated with 23 high-level waste tanks at the Hanford Site. The classification of the wastes in all of these tanks is not final and some wastes may not be high-level wastes. However, until the characterization and classification is complete, all the tanks are treated as if they contain high-level waste. Of the 23 tanks, Tank 241-SY-101 (referred to as Tank 101-SY) has exhibited significant episodic releases of flammable gases (hydrogen and nitrous oxide) for the past 10 years. The major near-term focus of this program is for the understanding and stabilization of this tank. An understanding of the mechanism for gas generation and the processes for the episodic release will be obtained through sampling of the tank contents, laboratory studies, and modeling of the tank behavior. Additional information will be obtained through new and upgraded instrumentation for the tank. A number of remediation, or stabilization, concepts will be evaluated for near-term (2 to 3 years) applications to Tank 101-SY. Detailed safety assessments are required for all activities that will occur in the tank (sampling, removal of equipment, and addition of new instruments). This program plan presents a discussion of each task, provides schedules for near-term activities, and gives a summary of the expected work for fiscal years 1991, 1992, and 1993. 16 refs., 7 figs., 8 tabs.

  11. THE EFFECT OF THE PRESENCE OF OZONE ON THE LOWER FLAMMABILITY LIMIT OF HYDROGEN IN VESSELS CONTAINING SAVANNAH RIVER SITE HIGH LEVEL WASTE

    Energy Technology Data Exchange (ETDEWEB)

    Sherburne, C.

    2012-01-12

    The Enhanced Chemical Cleaning (ECC) process uses ozone to effect the oxidation of metal oxalates produced during the dissolution of sludge in the Savannah River Site (SRS) waste tanks. The ozone reacts with the metal oxalates to form metal oxide and hydroxide precipitants, and the CO{sub 2}, O{sub 2}, H{sub 2}O and any unreacted O{sub 3} gases are discharged into the vapor space. In addition to the non-radioactive metals in the waste, however, the SRS radioactive waste also contains a variety of radionuclides, hence, hydrogen gas is also present in the vapor space of the ECC system. Because hydrogen is flammable, the impact of this resultant gas stream on the Lower Flammability Limit (LFL) of hydrogen must be understood for all possible operating scenarios of both normal and off-normal situations, with particular emphasis at the elevated temperatures and pressures of the typical ECC operating conditions. Oxygen is a known accelerant in combustion reactions, but while there are data associated with the behavior of hydrogen/oxygen environments, recent, relevant studies addressing the effect of ozone on the flammability limit of hydrogen proved scarce. Further, discussions with industry experts verified the absence of data in this area and indicated that laboratory testing, specific to defined operating parameters, was needed to comprehensively address the issue. Testing was thus designed and commissioned to provide the data necessary to support safety related considerations for the ECC process. A test matrix was developed to envelope the bounding conditions considered credible during ECC processing. Each test consists of combining a gas stream of high purity hydrogen with a gas stream comprised of a specified mixture of ozone and oxygen in a temperature and pressure regulated chamber such that the relative compositions of the two streams are controlled. The gases are then stirred to obtain a homogeneous mixture and ignition attempted by applying 10J of energy to a

  12. Controllable preparation of copper phthalocyanine single crystal nano column and its chlorine gas sensing properties

    Directory of Open Access Journals (Sweden)

    Jianhong Zhao

    2016-09-01

    Full Text Available The unsubstituted copper phthalocyanine (CuPc single crystal nano columns were fabricated for the first time as chlorine (Cl2 gas sensors in this paper. The nano columns of CuPc have been prepared on different substrates via template-free physical vapor deposition (PVD approach. The growth mechanism of CuPc nano column on quartz was explored and the same condition used on other substrates including glass, sapphire (C-plane, M-plane, R-plane, Si and SiO2/Si came to a same conclusion, which confirmed that the aligned growth of CuPc nano column is not substrate-dependent. And then the CuPc nano column with special morphology was integrated as in-situ sensor device which exhibits high sensitivity and selectivity towards Cl2 at room temperature with a minimum detection limit as low as 0.08 ppm. The response of sensor was found to increase linearly (26∼659% with the increase for Cl2 within concentration range (0.08∼4.0ppm. These results clearly demonstrate the great potential of the nano column growth and device integration approach for sensor device.

  13. The Efficiency of Non-Flammable Functional Underwear

    Directory of Open Access Journals (Sweden)

    Glombikova Viera

    2014-09-01

    Full Text Available This study evaluates the efficiency of non-flammable functional underwear used as a secondary heat barrier in extreme conditions. Five groups of knitted fabrics were analysed for flame resistance and selected physiological properties (water vapour permeability, air permeability, thermal resistance and liquid moisture transport by moisture management transport. The results indicated similar levels of flame resistance for the materials tested but show important differences in terms of physiological characteristics, namely liquid moisture transport, which influences the safety and comfort of protective clothing.

  14. Influence of temperature on flammability limits of heat treating atmosphere%温度对热处理气氛可燃极限的影响

    Institute of Scientific and Technical Information of China (English)

    Dwyer John; Hansel James G.; Philips Tom; Chen Wayne; 侯学涛

    2011-01-01

    讨论了热处理气氛中常用气体成分的可燃极限,分析了上下可燃极限与温度的关系。提出了一个应用CAFT理论推断气氛可燃极限的方法,同时解释了温度对热处理炉安全操作的影响。%The flammability limits of gas constituents commonly used in heat treating atmospheres were discussed.The upper and lower flammability limits,with respect to temperature,were analyzed.A method was described for determining these limits using CAFT theory.This temperature factor and its impact on safe furnace practices were addressed.

  15. Outlier treatment for improving parameter estimation of group contribution based models for upper flammability limit

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Abildskov, Jens; Sin, Gürkan

    2015-01-01

    Flammability data is needed to assess the risk of fire and explosions. This study presents a new group contribution (GC) model to predict the upper flammability limit UFL oforganic chemicals. Furthermore, it provides a systematic method for outlier treatment inorder to improve the parameter...

  16. Differences in leaf flammability, leaf traits and flammability-trait relationships between native and exotic plant species of dry sclerophyll forest.

    Science.gov (United States)

    Murray, Brad R; Hardstaff, Lyndle K; Phillips, Megan L

    2013-01-01

    The flammability of plant leaves influences the spread of fire through vegetation. Exotic plants invading native vegetation may increase the spread of bushfires if their leaves are more flammable than native leaves. We compared fresh-leaf and dry-leaf flammability (time to ignition) between 52 native and 27 exotic plant species inhabiting dry sclerophyll forest. We found that mean time to ignition was significantly faster in dry exotic leaves than in dry native leaves. There was no significant native-exotic difference in mean time to ignition for fresh leaves. The significantly higher fresh-leaf water content that was found in exotics, lost in the conversion from a fresh to dry state, suggests that leaf water provides an important buffering effect that leads to equivalent mean time to ignition in fresh exotic and native leaves. Exotic leaves were also significantly wider, longer and broader in area with significantly higher specific leaf area-but not thicker-than native leaves. We examined scaling relationships between leaf flammability and leaf size (leaf width, length, area, specific leaf area and thickness). While exotics occupied the comparatively larger and more flammable end of the leaf size-flammability spectrum in general, leaf flammability was significantly correlated with all measures of leaf size except leaf thickness in both native and exotic species such that larger leaves were faster to ignite. Our findings for increased flammability linked with larger leaf size in exotics demonstrate that exotic plant species have the potential to increase the spread of bushfires in dry sclerophyll forest.

  17. Differences in leaf flammability, leaf traits and flammability-trait relationships between native and exotic plant species of dry sclerophyll forest.

    Directory of Open Access Journals (Sweden)

    Brad R Murray

    Full Text Available The flammability of plant leaves influences the spread of fire through vegetation. Exotic plants invading native vegetation may increase the spread of bushfires if their leaves are more flammable than native leaves. We compared fresh-leaf and dry-leaf flammability (time to ignition between 52 native and 27 exotic plant species inhabiting dry sclerophyll forest. We found that mean time to ignition was significantly faster in dry exotic leaves than in dry native leaves. There was no significant native-exotic difference in mean time to ignition for fresh leaves. The significantly higher fresh-leaf water content that was found in exotics, lost in the conversion from a fresh to dry state, suggests that leaf water provides an important buffering effect that leads to equivalent mean time to ignition in fresh exotic and native leaves. Exotic leaves were also significantly wider, longer and broader in area with significantly higher specific leaf area-but not thicker-than native leaves. We examined scaling relationships between leaf flammability and leaf size (leaf width, length, area, specific leaf area and thickness. While exotics occupied the comparatively larger and more flammable end of the leaf size-flammability spectrum in general, leaf flammability was significantly correlated with all measures of leaf size except leaf thickness in both native and exotic species such that larger leaves were faster to ignite. Our findings for increased flammability linked with larger leaf size in exotics demonstrate that exotic plant species have the potential to increase the spread of bushfires in dry sclerophyll forest.

  18. Properties and flammability of major tree species in the Beijing area

    Institute of Scientific and Technical Information of China (English)

    Xiaoli WANG; Shukui NIU; Zhenguo KAN

    2009-01-01

    In order to examine correlations among the properties of tree species and to quantify the relationships between these properties and flammability, the properties of 20 tree species, consisting of heat of combustion, extractive contents, ash content, moisture content and basic density, were measured via experimental methods. In the first instance, the results show that, there are significant correlations between heat of combustion and extractive contents, ash content and basic density. Second, heat of combustion can be presented effectively in terms of linear regression models with extractive contents and ash content as independent variables. Third, a flammable model was developed based on four properties of tree species as independent variables, i.e., heat of combustion, extractive contents, ash content and moisture content. Finally, the flammability of 20 tree species is compared, ordered and ranked based on this flammable model. The conclusion is that flammability can be predicted from properties of tree species, which are significantly correlated among themselves.

  19. The relation between photoluminescence properties and gas pressure with [0001] InGaN single quantum well systems

    Science.gov (United States)

    Tsutsumi, Toshiaki; Alfieri, Giovanni; Kawakami, Yoichi; Micheletto, Ruggero

    2017-01-01

    We show for the first time that photoluminescence of InGaN single quantum wells (SQW) devices is related to the gas pressure in which the sample is immersed, also we give a model of the phenomena to suggest a possible cause. Our model shows a direct relation between experimental behavior and molecular coverage dynamics. This strongly suggests that the driving force of photoluminescence decrease is oxygen covering the surface of the device with a time dynamics that depends on the gas pressure. This aims to contribute to the understanding of the physical mechanism of the so-called optical memory effect and blinking phenomenon observed in these devices.

  20. Methods development for measuring and classifying flammability/combustibility of refrigerants. Interim report, task 2 - test plan

    Energy Technology Data Exchange (ETDEWEB)

    Heinonen, E.W.; Tapscott, R.E. [Univ. of New Mexico, Albuquerque, NM (United States)

    1994-07-01

    Regulations on alternative refrigerants and concerns for the environment are forcing the refrigeration industry to consider the use of potentially flammable fluids to replace CFC fluids currently in use. The objectives of this program are to establish the conditions under which refrigerants and refrigerant blends exhibit flammability and to develop appropriate methods to measure flammability.

  1. 16 CFR 1145.3 - Extremely flammable contact adhesives; risk of burns from explosive vapor ignition and flashback...

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Extremely flammable contact adhesives; risk... TO OTHER ACTS UNDER THE CONSUMER PRODUCT SAFETY ACT § 1145.3 Extremely flammable contact adhesives... associated with certain extremely flammable contact adhesives under the Consumer Product Safety Act...

  2. Flammability Tests on Hot Surface for Several Hydraulic Fluids

    Directory of Open Access Journals (Sweden)

    L. Deleanu

    2011-09-01

    Full Text Available Industrial equipment using hydraulic fluids are design to accept higher load and speed, implicitly higher temperatures, including for fluids. Leakages from enclosures like gear boxes or hydraulic systems could increase the risk of fluid reaching hot surfaces, thus producing fires hard to be controlled and isolated. The designer have to evaluate the flammability of fluids and they should select several solutions for a particular application in order to estimate the costs of different solutions and to mitigate the risk of having accidental fires due to a specific fluid grade. The tests were done with the help of an original equipment allowing a dedicated soft assistance in order to protect the operator and to sustain reproducibility, according to the standard SR EN ISO 20823:2004 Petroleum and related products. The determination of the flammability characteristics of fluids in contact with hot surfaces - Manifold ignition test, There were tested the following grades of hydraulic oil HLP 68 X-Oil, HFC Prista, MHE 40 Prista (100% oil, a rapeseed oil (obtained after a dewaxing process and an emulsion oil-in-water (5% vol. MHE 40 Prista. There were identified distinct behaviours of these fluids under the test conditions

  3. Ultrasensitive and highly selective graphene-based single yarn for use in wearable gas sensor.

    Science.gov (United States)

    Yun, Yong Ju; Hong, Won G; Choi, Nak-Jin; Kim, Byung Hoon; Jun, Yongseok; Lee, Hyung-Kun

    2015-06-04

    Electric components based on fibers or textiles have been investigated owing to their potential applications in wearable devices. High performance on response to gas, drape-ability and washing durability are of important for gas sensors based on fiber substrates. In this report, we demonstrate the bendable and washable electronic textile (e-textile) gas sensors composed of reduced graphene oxides (RGOs) using commercially available yarn and molecular glue through an electrostatic self-assembly. The e-textile gas sensor possesses chemical durability to several detergent washing treatments and mechanical stability under 1,000 bending tests at an extreme bending radius of 1 mm as well as a high response to NO2 gas at room temperature with selectivity to other gases such as acetone, ethanol, ethylene, and CO2.

  4. Ultrasensitive and Highly Selective Graphene-Based Single Yarn for Use in Wearable Gas Sensor

    Science.gov (United States)

    Ju Yun, Yong; Hong, Won G.; Choi, Nak-Jin; Hoon Kim, Byung; Jun, Yongseok; Lee, Hyung-Kun

    2015-06-01

    Electric components based on fibers or textiles have been investigated owing to their potential applications in wearable devices. High performance on response to gas, drape-ability and washing durability are of important for gas sensors based on fiber substrates. In this report, we demonstrate the bendable and washable electronic textile (e-textile) gas sensors composed of reduced graphene oxides (RGOs) using commercially available yarn and molecular glue through an electrostatic self-assembly. The e-textile gas sensor possesses chemical durability to several detergent washing treatments and mechanical stability under 1,000 bending tests at an extreme bending radius of 1 mm as well as a high response to NO2 gas at room temperature with selectivity to other gases such as acetone, ethanol, ethylene, and CO2.

  5. A Room-temperature Hydrogen Gas Sensor Using Palladium-decorated Single-Walled Carbon Nanotube/Si Heterojunction

    Directory of Open Access Journals (Sweden)

    Yong Gang DU

    2016-05-01

    Full Text Available We report a room-temperature (RT hydrogen gas (H2 sensor based on palladium-decorated single-walled carbon nanotube/Si (Pd-SWNTs/Si heterojunction. The current-voltage (I-V curves of the Pd-SWNTs/Si heterojunction in different concentrations of H2 were measured. The experimental results reveal that the Pd-SWNTs/Si heterojunction exhibits high H2 response. After exposure to 0.02 %, 0.05 %, and 0.1 % H2 for 10 min, the resistance of the heterojunction increases dramatically. The response is 122 %, 269 % and 457 %, respectively. A simple interfacial theory is used to understand the gas sensitivity results. This approach is a step toward future CNTs-based gas sensors for practical application.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12925

  6. Novel single-layer gas diffusion layer based on PTFE/carbon black composite for proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Chen-Yang, Y.W.; Hung, T.F.; Yang, F.L. [Department of Chemistry and Center for Nanotechnology, Chung Yuan Christian University, Chung-Li 32023 (China); Huang, J. [Yeu Ming Tai Chemical Industrial Co., Ltd, Taichung 40768 (China)

    2007-11-08

    A series of poly(tetrafluoroethylene)/carbon black composite-based single-layer gas diffusion layers (PTFE/CB-GDLs) for proton exchange membrane fuel cell (PEMFC) was successfully prepared from carbon black and un-sintered PTFE, which included powder resin and colloidal dispersion, by a simple inexpensive method. The scanning electron micrographs of PTFE/CB-GDLs indicated that the PTFE resins were homogeneously dispersed in the carbon black matrix and showed a microporous layer (MPL)-like structure. The as-prepared PTFE/CB-GDLs exhibited good mechanical property, high gas permeability, and sufficient water repellency. The best current density obtained from the PEMFC with the single-layer PTFE/CB-GDL was 1.27 and 0.42 A cm{sup -2} for H{sub 2}/O{sub 2} and H{sub 2}/air system, respectively. (author)

  7. Development and Design of a Single-Stage Cryogenic Modulator for Comprehensive Two-Dimensional Gas Chromatography.

    Science.gov (United States)

    Mostafa, Ahmed; Górecki, Tadeusz

    2016-05-17

    A new liquid nitrogen-based single-stage cryogenic modulator was developed and characterized. In addition, a dedicated liquid nitrogen delivery system was developed. A well-defined restriction placed inside a deactivated fused silica capillary was used to increase the cooling surface area and provide very efficient trapping. At the same time, it enabled modulation of the carrier gas flow owing to changes in gas viscosity with temperature. Gas flow is almost unimpeded at the trapping temperature but reduced to nearly zero at the desorption temperature, which prevents analyte breakthrough. Peak widths for n-alkanes of 30-40 ms at half height were obtained. Most importantly, even the solvent peak could be modulated, which is not feasible with any commercially available thermal modulator. Evaluation of the newly developed system in two-dimensional gas chromatography (GC × GC) separations of some real samples such as regular gasoline and diesel fuel showed that the analytical performance of this single-stage modulator is fully competitive to those of the more complicated dual-stage modulators.

  8. Creation and recovery of a W(111) single atom gas field ion source.

    Science.gov (United States)

    Pitters, Jason L; Urban, Radovan; Wolkow, Robert A

    2012-04-21

    Tungsten single atom tips have been prepared from a single crystal W(111) oriented wire using the chemical assisted field evaporation and etching method. Etching to a single atom tip occurs through a symmetric structure and leads to a predictable last atom unlike etching with polycrystalline tips. The single atom tip formation procedure is shown in an atom by atom removal process. Rebuilds of single atom tips occur on the same crystalline axis as the original tip such that ion emission emanates along a fixed direction for all tip rebuilds. This preparation method could be utilized and developed to prepare single atom tips for ion source development.

  9. Galactic evolution. I - Single-zone models. [encompassing stellar evolution and gas-star dynamic theories

    Science.gov (United States)

    Thuan, T. X.; Hart, M. H.; Ostriker, J. P.

    1975-01-01

    The two basic approaches of physical theory required to calculate the evolution of a galactic system are considered, taking into account stellar evolution theory and the dynamics of a gas-star system. Attention is given to intrinsic (stellar) physics, extrinsic (dynamical) physics, and computations concerning the fractionation of an initial mass of gas into stars. The characteristics of a 'standard' model and its variants are discussed along with the results obtained with the aid of these models.

  10. Gas entrainment by one single French PWR spray, SARNET-2 spray benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Malet, J., E-mail: jeanne.malet@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, Saclay (France); Mimouni, S., E-mail: stephane.mimouni@edf.fr [Electricité de France, EDF MF2E, Chatou (France); Manzini, G., E-mail: giovanni.manzini@rse-web.it [RSE, Milano (Italy); Xiao, J., E-mail: jianjun.xiao@kit.edu [IKET, KIT, Karlsruhe (Germany); Vyskocil, L., E-mail: vyl@ujv.cz [UJV Rez (Czech Republic); Siccama, N.B., E-mail: siccama@nrg.eu [NRG, Safety and Power (Netherlands); Huhtanen, R., E-mail: risto.huhtanen@vtt.fi [VTT, PO Box 1000, FI-02044 VTT (Finland)

    2015-02-15

    Highlights: • This paper presents a benchmark performed in the frame of the SARNET-2 EU project. • It concerns momentum transfer between a PWR spray and the surrounding gas. • The entrained gas velocities can vary up to 100% from one code to another. • Simplified boundary conditions for sprays are generally used by the code users. • It is shown how these simplified conditions impact the gas entrainment. - Abstract: This paper presents a benchmark performed in the frame of the SARNET-2 EU project, dealing with momentum transfer between a real-scale PWR spray and the surrounding gas. It presents a description of the IRSN tests on the CALIST facility, the participating codes (8 contributions), code-experiment and code-to-code comparisons. It is found that droplet velocities are almost well calculated one meter below the spray nozzle, even if the spread of the spray is not recovered and the values of the entrained gas velocity vary up to 100% from one code to another. Concerning sensitivity analysis, several ‘simplifications’ have been made by the contributors, especially based on the boundary conditions applied at the location where droplets are injected. It is shown here that such simplifications influence droplet and entrained gas characteristics. The next step will be to translate these conclusions in terms of variables representative of interesting parameters for nuclear safety.

  11. Lean flammability limit of downward propagating hydrogen-air flames

    Science.gov (United States)

    Patnaik, G.; Kailasanath, K.

    1992-01-01

    Detailed multidimensional numerical simulations that include the effects of wall heat losses have been performed to study the dynamics of downward flame propagation and extinguishment in lean hydrogen-air mixtures. The computational results show that a downward propagating flame in an isothermal channel has a flammability limit of around 9.75 percent. This is in excellent agreement with experimental results. Also in excellent agreement are the detailed observations of the flame behavior at the point of extinguishment. The primary conclusion of this work is that detailed numerical simulations that include wall heat losses and the effect of gravity can adequately simulate the dynamics of the extinguishment process in downward-propagating hydrogen-air flames. These simulations can be examined in detail to gain understanding of the actual extinction process.

  12. Thermoplastic Polyurethane Elastomer Nanocomposites: Morphology, Thermophysical, and Flammability Properties

    Directory of Open Access Journals (Sweden)

    Wai K. Ho

    2010-01-01

    Full Text Available Novel materials based on nanotechnology creating nontraditional ablators are rapidly changing the technology base for thermal protection systems. Formulations with the addition of nanoclays and carbon nanofibers in a neat thermoplastic polyurethane elastomer (TPU were melt-compounded using twin-screw extrusion. The TPU nanocomposites (TPUNs are proposed to replace Kevlar-filled ethylene-propylene-diene-monomer rubber, the current state-of-the-art solid rocket motor internal insulation. Scanning electron microscopy analysis was conducted to study the char characteristics of the TPUNs at elevated temperatures. Specimens were examined to analyze the morphological microstructure during the pyrolysis reaction and in fully charred states. Thermophysical properties of density, specific heat capacity, thermal diffusivity, and thermal conductivity of the different TPUN compositions were determined. To identify dual usage of these novel materials, cone calorimetry was employed to study the flammability properties of these TPUNs.

  13. FLAMMABILITY OF ARALDITE BASED COMPOSITE MIXED WITH INORGANIC RETARDANTS

    Directory of Open Access Journals (Sweden)

    ALI I. AL-MOSAWI

    2012-10-01

    Full Text Available Flammability characteristics of araldite based composite mixed with inorganic hybrid flame retardant represent zinc borate - antimony trioxide as a surface layer(4mm thickness have been studied by thermal erosion test . Antimony trioxide was added to zinc borate with various amounts (10%,20% and 30% to forming a hybrid flame retardant for enhance the action of this material to react flame . The result composite material was exposed to a direct flame generated from Oxyacetylene torch (3000ºC with different flame exposure intervals (10,20mm, and studies the range of resistance of retardant material layer to the flames and protected the substrate. The optimum results were with large percentage from protective layer which is zinc borate-30% antimony trioxide and large exposed distance.

  14. Milestone Report #2: Direct Evaporator Leak and Flammability Analysis Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen

    2013-09-01

    The direct evaporator is a simplified heat exchange system for an Organic Rankine Cycle (ORC) that generates electricity from a gas turbine exhaust stream. Typically, the heat of the exhaust stream is transferred indirectly to the ORC by means of an intermediate thermal oil loop. In this project, the goal is to design a direct evaporator where the working fluid is evaporated in the exhaust gas heat exchanger. By eliminating one of the heat exchangers and the intermediate oil loop, the overall ORC system cost can be reduced by approximately 15%. However, placing a heat exchanger operating with a flammable hydrocarbon working fluid directly in the hot exhaust gas stream presents potential safety risks. The purpose of the analyses presented in this report is to assess the flammability of the selected working fluid in the hot exhaust gas stream stemming from a potential leak in the evaporator. Ignition delay time for cyclopentane at temperatures and pressure corresponding to direct evaporator operation was obtained for several equivalence ratios. Results of a computational fluid dynamic analysis of a pinhole leak scenario are given.

  15. Radiation of X-rays using polarized LiNbO3 single crystal in low-pressure ambient gas.

    Science.gov (United States)

    Fukao, Shinji; Nakanishi, Yoshikazu; Mizoguchi, Tadahiro; Ito, Yoshiaki; Yoshikado, Shinzo

    2009-09-01

    The dependence of X-ray intensity on the pressure and type of ambient gas was investigated for LiNbO(3) single crystals polarized in the c-axis direction at pressures of approximately 1 to 30 Pa. Ionization of surrounding gas molecules by the electric field generated by the crystal led to the production of both positive ions and free electrons. The electrons were accelerated toward a Cu target, radiating both white X-rays and X-rays specific to the crystal or target material by bremsstrahlung. The integrated X-ray intensity per cycle in the energy range 1 to 20 keV showed a local maximum value at a pressure P(max). The logarithm of P(max) was proportional to the Boltzmann factor using the first ionization energy of each ambient gas molecule. The value of P(max) was found to be independent of the electrical surface area of the crystal. The integrated X-ray intensity was approximated qualitatively by a quadratic function with pressure, which was upwardly convex. It was found that one of the causes of the reduction in X-ray intensity at pressures P > P(max) is the adsorption of positive ions generated by the ionization of gas molecules on the negative electric surface. It was also discovered that the lifetime of the X-ray radiation device could be improved when the X-ray radiation case was covered with another hermetically sealed decompression case. The gas with the smallest first ionization energy, with a partial pressure of P(max), was enclosed inside the X-ray radiation case (inner case) and the gas with the largest first ionization energy was enclosed at a suitable pressure between the inner and outer cases.

  16. Dynamic structure factor in single- and two-species thermal GBL lattice gas

    Science.gov (United States)

    Dubbeldam, D.; Hoekstra, A. G.; Sloot, P. M. A.

    2000-07-01

    The two-dimensional 19-bits GBL lattice gas model conserves energy in a non-trivial way, allowing temperature, temperature gradients, and heat conduction. We describe the thermodynamics of the model, its equilibrium properties, and confirm the change of sound speed with energy density at fixed density with simulation results. The sound speed, the sound damping, and the thermal diffusivity are extracted from the dynamic structure factor and shown for various energy densities at fixed density. We have extended the 19 bits GBL model with multiple-species (miscible fluid model) and have measured the dynamic structure factor for this two-component thermal lattice gas model.

  17. All-optical production and trapping of metastable noble gas atoms down to the single atom regime

    CERN Document Server

    Kohler, M; Sahling, P; Sieveke, C; Jerschabek, N; Kalinowski, M B; Becker, C; Sengstock, K

    2014-01-01

    The determination of isotope ratios of noble gas atoms has many applications e.g. in physics, nuclear arms control, and earth sciences. For several applications, the concentration of specific noble gas isotopes (e.g. Kr and Ar) is so low that single atom detection is highly desirable for a precise determination of the concentration. As an important step in this direction, we demonstrate operation of a krypton Atom Trap Trace Analysis (ATTA) setup based on a magneto-optical trap (MOT) for metastable Kr atoms excited by all-optical means. Compared to other state-of-the-art techniques for preparing metastable noble gas atoms, all-optical production is capable of overcoming limitations regarding minimal probe volume and avoiding cross-contamination of the samples. In addition, it allows for a compact and reliable setup. We identify optimal parameters of our experimental setup by employing the most abundant isotope Kr-84, and demonstrate single atom detection within a 3D MOT.

  18. A NEW OPTIMISED DESIGN OF SINGLE PHASE GAS INSULATED CONE TYPE INSULATOR

    Directory of Open Access Journals (Sweden)

    M. GOPI CHAND NAIK

    2012-03-01

    Full Text Available The Gas Insulated Substation (GIS have various advantages like Compactness, immunity from environmental conditions, high operational reliability, low maintenance cost. In a number of GIS installations, the main design considerations involved in gas insulated equipment are at cone insulator, gas and metal interface. Hence there isa need for control of electric stresses in order to reduce internal discharges, surface discharges to the enclosure surface. In conventional approach, in order to reduce such distortion of electric field, many techniques are applied like, control of the spacer shape, additional shielding of electrodes for relaxation of electric field around spacer and low permittivity of spacer material. The new techniques of Functionally Gradient Material (FGMspacer has been proposed in this paper. In this paper the applicability of FGM spacer for gas insulated power apparatus has been verified. In the FGM spacer, a spatial distribution of permittivity for the control of theelectric field distribution in and around the spacer is used. The electric field calculations for several types of FGM spacers have been carried out using Finite Element Method (FEM. The electric field distribution along the radial distance of the spacer insulator have been obtained for various FGM materials and results arecompared.

  19. Environmental Transmission Electron Microscopy (ETEM) Studies of Single Iron Nanoparticle Carburization in Synthesis Gas

    DEFF Research Database (Denmark)

    Liu, Xi; Zhang, Chenghua; Li, Yongwang

    2017-01-01

    Structuralevolution of iron nanoparticles involving the formationand growth of iron carbide nuclei in the iron nanoparticle was directlyvisualized at the atomic level, using environmental transmission electronmicroscopy (TEM) under reactive conditions mimicking Fischer–Tropschsynthesis. Formation...... and electronenergy-loss spectra provides a detailed picture from initial activationto final degradation of iron under synthesis gas....

  20. 可燃气体-空气-氮气混合物爆炸极限的预测%Prediction of flammability limits of gaseous mixtures of combustible-air-nitrogen

    Institute of Scientific and Technical Information of China (English)

    李国梁; 潘勇; 蒋军成

    2012-01-01

    可燃气体爆炸是工业生产中时有发生的重大灾害事故类型之一,爆炸极限是判断其爆炸危险性的一个重要参数.工业过程中常采用向被保护的设备中引入惰性气体的方法来防止爆炸事故的发生.本研究采用计算绝热火焰温度法,对几种常见的有机可燃气体与氮气混合物的爆炸极限范围进行预测计算,并将计算值与文献值进行比较.结果表明该方法对爆炸下限的预测与实验值吻合程度较好,对爆炸上限的预测则存在一定的误差,并对产生误差的主要原因进行分析.%Explosions of flammable gases were the possible major disasters occurring in industrial processes, and the flammability limits were important parameters to judge the explosion risk of flammable substances. Inerting was a common procedure in process industries to lower the likelihood of explosion by adding an inert gas to a combustible mixture. The inert gas was usually nitrogen or carbon dioxide. In this study, the calculated adiabatic flame temperatures (CAFT) were used to forecast the flammability limits of several organic flammable gases diluted with inert nitrogen, and the calculated values were compared with observed values in available literatures. It was found that the CAFT method could well describe the lower flammability limit of combustible diluted with inert nitrogen, while deviation existed between the observed and calculated values in the case of upper flammability limit, and the main reasons of the error were analyzed.

  1. Investigation of the Extinguishing Features for Liquid Fuels and Organic Flammable Liquids Atomized by a Water Flow

    Directory of Open Access Journals (Sweden)

    Voytkov Ivan V.

    2016-01-01

    Full Text Available The processes of heat and mass transfer were investigated experimentally while moving and evaporating the atomized water flow in high-temperature combustion products of typical liquid fuels and organic flammable liquids: gasoline, kerosene, acetone, crude oil, industrial alcohol. We determined typical periods of liquid extinguishing by an atomized water flow of various dispersability. Data of the discharge of extinguishing medium corresponding to various parameters of atomization and duration of using the atomization devices was presented. It is shown that Um≈3.5 m/s is a minimal outflow velocity of droplets during moving while passing the distance of 1m in the high-temperature gas medium to stop the combustion of organic liquids.

  2. Evaluating Material Flammability in Microgravity and Martian Gravity Compared to the NASA Standard Normal Gravity Test

    Science.gov (United States)

    Oslon, Sandra. L.; Ferkul, Paul

    2012-01-01

    Drop tower tests are conducted at Martian gravity to determine the flammability of three materials compared to previous tests in other normal gravity and reduced gravity environments. The comparison is made with consideration of a modified NASA standard test protocol. Material flammability limits in the different gravity and flow environments are tabulated to determine the factor of safety associated with normal gravity flammability screening. Previous testing at microgravity and Lunar gravity indicated that some materials burned to lower oxygen concentrations in low gravity than in normal gravity, although the low g extinction limit criteria are not the same as 1g due to time constraints in drop testing. Similarly, the data presented in this paper for Martian gravity suggest that there is a gravity level below Earth s at which materials burn more readily than on Earth. If proven for more materials, this may indicate the need to include a factor of safety on 1g flammability limits.

  3. Calculated flame temperature (CFT) modeling of fuel mixture lower flammability limits.

    Science.gov (United States)

    Zhao, Fuman; Rogers, William J; Mannan, M Sam

    2010-02-15

    Heat loss can affect experimental flammability limits, and it becomes indispensable to quantify flammability limits when apparatus quenching effect becomes significant. In this research, the lower flammability limits of binary hydrocarbon mixtures are predicted using calculated flame temperature (CFT) modeling, which is based on the principle of energy conservation. Specifically, the hydrocarbon mixture lower flammability limit is quantitatively correlated to its final flame temperature at non-adiabatic conditions. The modeling predictions are compared with experimental observations to verify the validity of CFT modeling, and the minor deviations between them indicated that CFT modeling can represent experimental measurements very well. Moreover, the CFT modeling results and Le Chatelier's Law predictions are also compared, and the agreement between them indicates that CFT modeling provides a theoretical justification for the Le Chatelier's Law.

  4. 49 CFR 175.310 - Transportation of flammable liquid fuel; aircraft only means of transportation.

    Science.gov (United States)

    2010-10-01

    ... impracticable. The stowage requirements of § 175.75(a) do not apply to a person operating an aircraft under the... racks or slings. (c) Flammable liquid fuels may be carried on a cargo aircraft, subject to the...

  5. Non-Flammable Crew Clothing Utilizing Phosphorus-Based Fire Retardant Polymers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For maintaining U.S. leadership role in space exploration, there is an urgent need to develop non-flammable shirts, shorts, sweaters, and jackets without...

  6. Detecting Pesticide Residue by Using Modulating Temperature Over a Single SnO2-Based Gas Sensor

    Directory of Open Access Journals (Sweden)

    Zengliang Yu

    2003-09-01

    Full Text Available A new rapid detecting method (called dynamic measurements was reported to detect and distinguish the presence of two pesticide gases in the ambient atmosphere. The method employed only a single SnO2-based gas sensor in a rectangular temperature mode to perform the qualitative analysis of a binary gas mixture (acephate and trichlorphon in air. Polar plots was used for quantitative analysis which the feature extraction was performed by FFT. Experimental results showed that high selectivity of the sensor achieved in the range of 250~3000C and modulating frequency 20mHz, one can easily observe the qualitative difference among the response to pure acephate and trichlorphon gases of the same concentration and to the mixture, and the concentration of pesticide gases can be obtained based on the changes of polar plots.

  7. Development of Metal-impregnated Single Walled Carbon Nanotubes for Toxic Gas Contaminant Control in Advanced Life Support Systems

    Science.gov (United States)

    Cinke, Martin; Li, Jing; Chen, Bin; Wignarajah, Kanapathipillai; Pisharody, Suresh A.; Fisher, John W.; Delzeit, Lance; Meyyappan, Meyya; Partridge, Harry; Clark, Kimberlee

    2003-01-01

    The success of physico-chemical waste processing and resource recovery technologies for life support application depends partly on the ability of gas clean-up systems to efficiently remove trace contaminants generated during the process with minimal use of expendables. Highly purified metal-impregnated carbon nanotubes promise superior performance over conventional approaches to gas clean-up due to their ability to direct the selective uptake gaseous species based both on the nanotube s controlled pore size, high surface area, and ordered chemical structure that allows functionalization and on the nanotube s effectiveness as a catalyst support material for toxic contaminants removal. We present results on the purification of single walled carbon nanotubes (SWCNT) and efforts at metal impregnation of the SWCNT's.

  8. Clothing Flammability and Burn Injuries: Public Opinion Concerning an Overlooked, Preventable Public Health Problem.

    Science.gov (United States)

    Frattaroli, Shannon; Spivak, Steven M; Pollack, Keshia M; Gielen, Andrea C; Salomon, Michele; Damant, Gordon H

    2016-01-01

    The objective of this study was to describe knowledge of clothing flammability risk, public support for clothing flammability warning labels, and stronger regulation to reduce the risk. As part of a national survey of homeowners about residential sprinkler systems, the authors included questions about clothing flammability. The authors used an online web panel to sample homeowners and descriptive methods to analyze the resulting data. The sample included 2333 homeowners. Knowledge of clothing flammability and government oversight of clothing flammability risk was low. Homeowners were evenly split about the effectiveness of current standards; however, when presented with clothing-related burn injury and death data, a majority (53%) supported stricter standards. Most homeowners (64%) supported warning labels and indicated that such labels would either have no effect on their purchasing decisions (64%) or be an incentive (24%) to purchase an item. Owners of sprinkler-equipped homes were more likely to support these interventions than owners of homes without sprinkler systems. Public knowledge about clothing flammability risks is low. Most homeowners supported clothing labels to inform consumers of this risk and increased government intervention to reduce the risk.

  9. Design of single mode spiral photonic crystal fiber for gas sensing applications

    Directory of Open Access Journals (Sweden)

    Md. Ibadul Islam

    2017-04-01

    Full Text Available In this paper, a spiral shape photonic crystal fiber (S-PCF has been suggested as a gas sensor for detecting toxic or colorless gases as well as monitoring the air pollution by metering gas condensate elements in production facilities. Our reported S-PCF is micro-structured where two layers porous core is encircled by a spiral shape cladding. The geometrical parameters have altered to optimize the parameters of the proposed structure. The numerical analysis of the proposed S-PCF is performed by utilizing finite element method (FEM. The relative sensitivity and birefringence of the proposed S-PCF are 55.10% and 7.23 × 10−3 respectively at the 1.33 μm wavelength that lies in the absorption line of toxic gases (methane and hydrogen fluoride. Besides, effective area, nonlinear coefficient and V parameters are also described briefly.

  10. Analysis of regenerated single-shaft ceramic gas-turbine engines and resulting fuel economy in a compact car

    Science.gov (United States)

    Klann, J. L.; Tew, R. C., Jr.

    1977-01-01

    Ranges in design and off-design operating conditions of an advanced gas turbine and their effects on fuel economy were analyzed. The assumed engine incorporated a single stage radial flow turbine and compressor with fixed geometry. Fuel economies were calculated over the composite driving cycle with gasoline as the fuel. At a constant turbine-inlet temperature, with a regenerator sized for a full power effectiveness the best fuel economies ranged from 11.1 to 10.2 km/liter (26.2 to 22.5 mpg) for full power turbine tip speeds of 770 to 488m/sec (2530 to 1600ft/sec), respectively.

  11. Microgravity Flammability of PMMA Rods in Concurrent Flow

    Science.gov (United States)

    Olson, Sandra L.; Ferkul, Paul V.

    2015-01-01

    Microgravity experiments burning cast PMMA cylindrical rods in axial flow have been conducted aboard the International Space Station in the Microgravity Science Glovebox (MSG) facility using the Burning and Suppression of Solids (BASS) flow duct, as part of the BASS-II experiment. Twenty-four concurrent-flow tests were performed, focusing on finding flammability limits as a function of oxygen and flow speed. The oxygen was varied by using gaseous nitrogen to vitiate the working volume of the MSG. The speed of the flow parallel to the rod was varied using a fan at the entrance to the duct. Both blowoff and quenching limits were obtained at several oxygen concentrations. Each experiment ignited the rod at the initially hemispherical stagnation tip of the rod, and allowed the flame to develop and heat the rod at a sufficient flow to sustain burning. For blowoff limit tests, the astronaut quickly turned up the flow to obtain extinction. Complementary 5.18-second Zero Gravity Facility drop tests were conducted to compare blowoff limits in short and long duration microgravity. For quenching tests, the flow was incrementally turned down and the flame allowed to stabilize at the new flow condition for at least the solid-phase response time before changing it again. Quenching was observed when the flow became sufficiently weak that the flame could no longer provide adequate heat flux to compensate for the heat losses (conduction into the rod and radiation). A surface energy balance is presented that shows the surface radiative loss exceeds the conductive loss into the rod near the limit. The flammability boundary is shown to represent a critical Damkohler number, expressed in terms of the reaction rate divided by the stretch rate. For the blowoff branch, the boundary exhibits a linear dependence on oxygen concentration and stretch rate, indicating that the temperature at blowoff must be fairly constant. For the quenching branch, the dominance of the exponential nature of

  12. Synthesis and Gas Sensing Properties of Single La-Doped SnO2 Nanobelts

    Directory of Open Access Journals (Sweden)

    Yuemei Wu

    2015-06-01

    Full Text Available Single crystal SnO2 nanobelts (SnO2 NBs and La-SnO2 nanobelts (La-SnO2 NBs were synthesized by thermal evaporation. Both a single SnO2 NB sensor and a single La-SnO2 NB sensor were developed and their sensing properties were investigated. It is found that the single La-SnO2 NB sensor had a high sensitivity of 8.76 to ethanediol at a concentration of 100 ppm at 230 °C, which is the highest sensitivity of a single SnO2 NB to ethanediol among three kinds of volatile organic (VOC liquids studied, including ethanediol, ethanol, and acetone. The La-SnO2 NBs sensor also exhibits a high sensitivity, good selectivity and long-term stability with prompt response time to ethanediol. The mechanism behind the enhanced sensing performance of La-doped SnO2 nanobelts is discussed.

  13. Synthesis and Gas Sensing Properties of Single La-Doped SnO₂ Nanobelts.

    Science.gov (United States)

    Wu, Yuemei; Zhang, Heng; Liu, Yingkai; Chen, Weiwu; Ma, Jiang; Li, Shuanghui; Qin, Zhaojun

    2015-06-16

    Single crystal SnO2 nanobelts (SnO2 NBs) and La-SnO2 nanobelts (La-SnO2 NBs) were synthesized by thermal evaporation. Both a single SnO2 NB sensor and a single La-SnO2 NB sensor were developed and their sensing properties were investigated. It is found that the single La-SnO2 NB sensor had a high sensitivity of 8.76 to ethanediol at a concentration of 100 ppm at 230 °C, which is the highest sensitivity of a single SnO2 NB to ethanediol among three kinds of volatile organic (VOC) liquids studied, including ethanediol, ethanol, and acetone. The La-SnO2 NBs sensor also exhibits a high sensitivity, good selectivity and long-term stability with prompt response time to ethanediol. The mechanism behind the enhanced sensing performance of La-doped SnO2 nanobelts is discussed.

  14. Surface-Anchored Poly(4-vinylpyridine)–Single-Walled Carbon Nanotube–Metal Composites for Gas Detection

    KAUST Repository

    Yoon, Bora

    2016-08-05

    A platform for chemiresistive gas detectors based upon single-walled carbon nanotube (SWCNT) dispersions stabilized by poly(4-vinylpyridine) (P4VP) covalently immobilized onto a glass substrate was developed. To fabricate these devices, a glass substrate with gold electrodes is treated with 3-bromopropyltrichlorosilane. The resulting alkyl bromide coating presents groups that can react with the P4VP to covalently bond (anchor) the polymer–SWCNT composite to the substrate. Residual pyridyl groups in P4VP not consumed in this quaternization reaction are available to coordinate metal nanoparticles or ions chosen to confer selectivity and sensitivity to target gas analytes. Generation of P4VP coordinated to silver nanoparticles produces an enhanced response to ammonia gas. The incorporation of soft Lewis acidic Pd2+ cations by binding PdCl2 to P4VP yields a selective and highly sensitive device that changes resistance upon exposure to vapors of thioethers. The latter materials have utility for odorized fuel leak detection, microbial activity, and breath diagnostics. A third demonstration makes use of permanganate incorporation to produce devices with large responses to vapors of volatile organic compounds that are susceptible to oxidation.

  15. Testing and analysis of a modernized freight wagon's elements flammability

    Science.gov (United States)

    Płaczek, M.; Wróbel, A.; Baier, A.

    2016-08-01

    Paper concerns an issue of freight wagon modernization using composite materials. The goal of the project is to elongate the period between repairs (by better corrosion protection) and improve conditions of exploitation of modernized freight wagons (for example easier unloading during winter conditions - no freezes of the charge to the freight wagon body shell). Application of the composite panels to the freight wagon's body shell was proposed as the solution that can solve mentioned problems. The composite panels composed of fiberglass and epoxy resin were proposed. They will be mounted on the body shell using rivet nuts. What is more the body shell of the modernized freight wagon will be painted using an anti-corrosion agent. In this paper the analysis of a flammability of the proposed composition (the composite plate made of fiberglass and epoxy resin mounted to the steel sheet with additional anticorrosion agent) is presented. In the paper results of laboratory tests conducted according to international standards are presented. A series of samples of elements of modernized freight wagons was tested using the created laboratory stand. Obtained results were averaged and the proposed material was assigned to the one of the class of materials for their combustibility.

  16. Model of ASTM Flammability Test in Microgravity: Iron Rods

    Science.gov (United States)

    Steinberg, Theodore A; Stoltzfus, Joel M.; Fries, Joseph (Technical Monitor)

    2000-01-01

    There is extensive qualitative results from burning metallic materials in a NASA/ASTM flammability test system in normal gravity. However, this data was shown to be inconclusive for applications involving oxygen-enriched atmospheres under microgravity conditions by conducting tests using the 2.2-second Lewis Research Center (LeRC) Drop Tower. Data from neither type of test has been reduced to fundamental kinetic and dynamic systems parameters. This paper reports the initial model analysis for burning iron rods under microgravity conditions using data obtained at the LERC tower and modeling the burning system after ignition. Under the conditions of the test the burning mass regresses up the rod to be detached upon deceleration at the end of the drop. The model describes the burning system as a semi-batch, well-mixed reactor with product accumulation only. This model is consistent with the 2.0-second duration of the test. Transient temperature and pressure measurements are made on the chamber volume. The rod solid-liquid interface melting rate is obtained from film records. The model consists of a set of 17 non-linear, first-order differential equations which are solved using MATLAB. This analysis confirms that a first-order rate, in oxygen concentration, is consistent for the iron-oxygen kinetic reaction. An apparent activation energy of 246.8 kJ/mol is consistent for this model.

  17. Explosion characteristics of flammable organic vapors in nitrous oxide atmosphere.

    Science.gov (United States)

    Koshiba, Yusuke; Takigawa, Tomihisa; Matsuoka, Yusaku; Ohtani, Hideo

    2010-11-15

    Despite unexpected explosion accidents caused by nitrous oxide have occurred, few systematic studies have been reported on explosion characteristics of flammable gases in nitrous oxide atmosphere compared to those in air or oxygen. The objective of this paper is to characterize explosion properties of mixtures of n-pentane, diethyl ether, diethylamine, or n-butyraldehyde with nitrous oxide and nitrogen using three parameters: explosion limit, peak explosion pressure, and time to the peak explosion pressure. Then, similar mixtures of n-pentane, diethyl ether, diethylamine, or n-butyraldehyde with oxygen and nitrogen were prepared to compare their explosion characteristics with the mixtures containing nitrous oxide. The explosion experiments were performed in a cylindrical vessel at atmospheric pressure and room temperature. The measurements showed that explosion ranges of the mixtures containing nitrous oxide were narrow compared to those of the mixtures containing oxygen. On the other hand, the maximum explosion pressures of the mixtures containing nitrous oxide were higher than those of the mixtures containing oxygen. Moreover, our experiments revealed that these mixtures differed in equivalence ratios at which the maximum explosion pressures were observed: the pressures of the mixtures containing nitrous oxide were observed at stoichiometry; in contrast, those of the mixtures containing oxygen were found at fuel-rich area. Chemical equilibrium calculations confirmed these behaviors.

  18. Comparison of axisymmetric and three-dimensional models for gas uptake in a single bifurcation during steady expiration.

    Science.gov (United States)

    Madasu, Srinath; Ultman, James S; Borhan, Ali

    2008-02-01

    Reactive gas uptake is predicted and compared in a single bifurcation at steady expiratory flow in terms of Sherwood number using an axisymmetric single-path model (ASPM) and a three-dimensional computational fluid dynamics model (CFDM). ASPM is validated in a two-generation geometry by comparing the average gas-phase mass transfer coefficients with the experimental values. ASPM predicted mass transfer coefficients within 20% of the experimental values. The flow and concentration variables in the ASPM were solved using Galerkin finite element method and in the CFDM using commercial finite element software FIDAP. The simulations were performed for reactive gas flowing at Reynolds numbers ranging from 60 to 350 in both symmetric bifurcation for three bifurcation angles, 30 deg, 70 deg, and 90 deg, and in an asymmetric bifurcation. The numerical models compared with each other qualitatively but quantitatively they were within 0.4-8% due to nonfully developed flow in the parent branch predicted by the CFDM. The radially averaged concentration variation along the axial location matched qualitatively between the CFDM and ASPM but quantitatively they were within 32% due to differences in the flow field. ASPM predictions compared well with the CFDM predictions for an asymmetric bifurcation. These results validate the simplified ASPM and the complex CFDM. ASPM predicts higher Sherwood number with a flat velocity inlet profile compared to a parabolic inlet velocity profile. Sherwood number increases with the inlet average velocity, wall mass transfer coefficient, and bifurcation angle since the boundary layer grows slower in the parent and daughter branches.

  19. Highly birefringent single mode spiral shape photonic crystal fiber based sensor for gas sensing applications

    Directory of Open Access Journals (Sweden)

    Md. Ibadul Islam

    2017-06-01

    Full Text Available This article represents a gas sensor based on spiral photonic crystal fiber (S-PCF for detecting harmful or colorless gasses and monitoring air pollution by metering gas condensate elements in production facilities. The proposed micro-structured S-PCF contains two layers porous core encircled by a spiral shape cladding. The geometrical parameters are tuned to fix the optimized S-PCF structure. The numerical analysis of the proposed S-PCF is performed by utilizing finite element method (FEM with circular perfectly match layer (C-PML. The relative sensitivity and birefringence of the recommended structure are 57.61% and 7.53 × 10−3 respectively at 1.33 μm wavelength on the absorption line of toxic gasses (methane and hydrogen fluoride. The exhibited beam divergence is about 4.1° at the same wavelength. Besides, beat length, nonlinear coefficient, effective area and V parameters are also described briefly for optimized S-PCF structure over broader wavelength range from 1 μm to 1.8 μm.

  20. Single-stage temperature-controllable water gas shift reactor with catalytic nickel plates

    Science.gov (United States)

    Park, Jin-Woo; Lee, Sung-Wook; Lee, Chun-Boo; Park, Jong-Soo; Lee, Dong-Wook; Kim, Sung-Hyun; Kim, Sung-Soo; Ryi, Shin-Kun

    2014-02-01

    In this study, a microstructured reactor with catalytic nickel plates is newly designed and developed for proper heat management in an exothermic water gas shift WGS reaction. The reactor is designed to increase the reactor capacity simply by numbering-up a set of a catalyst layers and heat exchanger layers. The WGS reactor is built up with two sets of a catalyst layers and heat exchanger layers. The performance of the reactor is verified by WGS testing with the variation of the furnace temperatures, gas hourly space velocity (GHSV) and coolant (N2) flow rate. At a GHSV of 10,000 h-1, CO conversion reaches the equilibrium value with a CH4 selectivity of ≤0.5% at the furnace temperature of ≥375 °C. At high GHSV (40,000 h-1), CO conversion decreases considerably because of the heat from the exothermic WGS reaction at a large reactants mass. By increasing the coolant flow rate, the heat from the WGS reaction is properly managed, leading an increase of the CO conversion to the equilibrium value at GHSV of 40,000 h-1.

  1. Understanding vented gas explosions

    Energy Technology Data Exchange (ETDEWEB)

    Lautkaski, R. [VTT Energy, Espoo (Finland). Energy Systems

    1997-12-31

    The report is an introduction to vented gas explosions for nonspecialists, particularly designers of plants for flammable gases and liquids. The phenomena leading to pressure generation in vented gas explosions in empty and congested rooms are reviewed. The four peak model of vented gas explosions is presented with simple methods to predict the values of the individual peaks. Experimental data on the external explosion of dust and gas explosions is discussed. The empirical equation relating the internal and external peak pressures in vented dust explosions is shown to be valid for gas explosion tests in 30 m{sup 3} and 550 m{sup 3} chambers. However, the difficulty of predicting the internal peak pressure in large chambers remains. Methods of explosion relief panel design and principles of vent and equipment layout to reduce explosion overpressures are reviewed. (orig.) 65 refs.

  2. Modeling and simulation of plasma gas flow driven by a single nanosecond-pulsed dielectric barrier discharge

    Science.gov (United States)

    Xu, S. Y.; Cai, J. S.; Li, J.

    2016-10-01

    A simplified (7 species and 9 processes) plasma kinetic model is proposed to investigate the mechanism of the plasma aerodynamic actuation driven by nanosecond-pulsed dielectric barrier discharge (NS-DBD). The governing equations include conservation equations for each species, the Poisson equation for the electric potential, and Navier-Stokes equations for the gas dynamic flow. Numerical simulations of plasma discharge and flow actuation on NS-DBD plasma actuators have been carried out. Key discharge characteristics and the responses of the quiescent air were reproduced and compared to those obtained in experiments and numerical simulations. Results demonstrate that the reduced plasma kinetic model is able to capture the dominant species and reactions to predict the actuation in complicated hydrodynamics. For the one-dimensional planar and two-dimensional symmetric NS-DBD, the forming of the sheath collapse is mainly due to the charge accumulation and secondary emission from the grounded electrode. Rapid species number density rise and electric field drop occur at the edge of the plasma sheath, where the space charge density gradient peaks. For the aerodynamic actuation with typical asymmetry electrodes, discharge characteristics have a core area on the right edge of the upper electrode, where the value can be much higher. The formation and propagation of the compression waves generated through rapid heating have also been performed and compared to those measured in a recent experiment. Energy release leads to gas expansion and forms a cylindrical shock wave, centering at the upper electrode tip with low gas acceleration. For the present single pulsed 12 kV case, the mean temperature of gas heating reaches about 575 K at 1 μs and decreases to about 460 K at 10 μs.

  3. 46 CFR 30.10-29 - Gas free-TB/ALL.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Gas free-TB/ALL. 30.10-29 Section 30.10-29 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Definitions § 30.10-29 Gas free—TB/ALL. The term gas free means free from dangerous concentrations of flammable or toxic gases. ...

  4. Computer Aided Design of Ni-Based Single Crystal Superalloy for Industrial Gas Turbine Blades

    Science.gov (United States)

    Wei, Xianping; Gong, Xiufang; Yang, Gongxian; Wang, Haiwei; Li, Haisong; Chen, Xueda; Gao, Zhenhuan; Xu, Yongfeng; Yang, Ming

    The influence of molybdenum, tungsten and cobalt on stress-rupture properties of single crystal superalloy PWA1483 has been investigated using the simulated calculation of JMatPro software which ha s been widely used to develop single crystal superalloy, and the effect of alloying element on the stability of strengthening phase has been revealed by using the Thermo-Calc software. Those properties calculation results showed that the increasing of alloy content could facilitate the precipitation of TCP phases and increase the lattice misfit between γ and γ' phase, and the effect of molybdenum, tantalum was the strongest and that of cobalt was the weakest. Then the chemical composition was optimized, and the selected compositions showed excellent microstructure stability and stress-rupture properties by the confirmation of d-electrons concept and software calculation.

  5. Comparative study of shale-gas production using single- and dual-continuum approaches

    KAUST Repository

    El-Amin, Mohamed

    2017-07-06

    In this paper, we explore the possibility of specifying the ideal hypothetical positions of matrices blocks and fractures in fractured porous media as a single-continuum reservoir model in a way that mimics the dual-porosity dual-permeability (DPDP) configuration. In order to get an ideal mimic, we use the typical configuration and geometrical hypotheses of the DPDP model for the SDFM. Unlike the DPDP model which consists of two equations for the two-continuum coupled by a transfer term, the proposed single-domain fracture model (SDFM) model consists of a single equation for the single-continuum. Each one of the two models includes slippage effect, adsorption, Knudsen diffusion, geomechanics, and thermodynamics deviation factor. For the thermodynamics calculations, the cubic Peng-Robinson equation of state is employed. The diffusion model is verified by calculating the total mass flux through a nanopore by combination of slip flow and Knudsen diffusion and compared with experimental data. A semi-implicit scheme is used for the time discretization while the thermodynamics equations are updated explicitly. The spatial discretization is done using the cell-centered finite difference (CCFD) method. Finally, numerical experiments are performed under variations of the physical parameters. Several results are discussed such as pressure, production rate and cumulative production. We compare the results of the two models using the same dimensions and physical and computational parameters. We found that the DPDP and the SDFM models production rate and cumulative production behave similarly with approximately the same slope but with some differences in values. Moreover, we found that the poroelasticity effect reduces the production rate and consequently the cumulative production rate but in the SDFM model the reservoir takes more time to achieve depletion than the DPDP model. The normal fracture factor which appears in the transfer term of the DPDP model is adjusted against

  6. Computational Study of Combustion Dynamics in a Single-Element Lean Direct Injection Gas Turbine Combustor

    Science.gov (United States)

    2013-12-01

    spray injection models , viz., Log Normal Distributed Drop Injection Model , Single Drop Injection Model and Hollow Cone Injection Model , have...not match experiment. The hollow cone injection model was able to predict the correct dominant acoustic mode (4L) but the pressure amplitude was...processes of pressure-swirl hollow - cone fuel sprays ," Atomization and Sprays , vol. 7, pp. 663-684, Nov-Dec 1997. 22 M. A. Patterson and R. D.

  7. Direct gas-phase synthesis of single-phase {beta}-FeSi{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bywalez, Robert, E-mail: robert.bywalez@uni-due.de; Orthner, Hans; Mehmedovic, Ervin [University of Duisburg-Essen, IVG, Institute for Combustion and Gas Dynamics - Reactive Fluids (Germany); Imlau, Robert; Kovacs, Andras; Luysberg, Martina [Forschungszentrum Juelich, Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute 5 (Germany); Wiggers, Hartmut [University of Duisburg-Essen, IVG, Institute for Combustion and Gas Dynamics - Reactive Fluids (Germany)

    2013-09-15

    For the first time, phase-pure {beta}-FeSi{sub 2} nanoparticles were successfully produced by gas-phase synthesis. We present a method to fabricate larger quantities of semiconducting {beta}-FeSi{sub 2} nanoparticles, with crystallite sizes between 10 and 30 nm, for solar and thermoelectric applications utilizing a hot-wall reactor. A general outline for the production of those particles by thermal decomposition of silane and iron pentacarbonyl is provided based on kinetic data. The synthesized particles are investigated by X-ray diffraction and transmission electron microscopy, providing evidence that the as-prepared materials are indeed {beta}-FeSi{sub 2}, while revealing morphological characteristics inherent to the nanoparticles created.

  8. Finite size effect on hydrogen gas sensing performance in single Pd nanowires

    Science.gov (United States)

    Jeon, Kye Jin; Jeun, Minhong; Lee, Eunsongyi; Lee, Jun Min; Lee, Kyoung-Il; von Allmen, Paul; Lee, Wooyoung

    2008-12-01

    We present the hydrogen sensing performance of individual Pd nanowires grown by electrodeposition into nanochannels of anodized aluminum oxide (AAO) templates investigated as a function of the nanowire diameter. Four-terminal devices based on individual Pd nanowires were found to successfully detect hydrogen gas (H2). Our experimental results show that the H2 sensing sensitivity increases and the response time decreases with decreasing diameter of Pd nanowires with d = 400, 200, 80 and 20 nm, due to the high surface-to-volume ratio and short diffusion paths, respectively. This is in qualitatively good agreement with simulated results obtained from a theoretical model based on a combination of the rate equation and diffusion equation.

  9. Finite size effect on hydrogen gas sensing performance in single Pd nanowires.

    Science.gov (United States)

    Jeon, Kye Jin; Jeun, Minhong; Lee, Eunsongyi; Lee, Jun Min; Lee, Kyoung-Il; von Allmen, Paul; Lee, Wooyoung

    2008-12-10

    We present the hydrogen sensing performance of individual Pd nanowires grown by electrodeposition into nanochannels of anodized aluminum oxide (AAO) templates investigated as a function of the nanowire diameter. Four-terminal devices based on individual Pd nanowires were found to successfully detect hydrogen gas (H(2)). Our experimental results show that the H(2) sensing sensitivity increases and the response time decreases with decreasing diameter of Pd nanowires with d = 400, 200, 80 and 20 nm, due to the high surface-to-volume ratio and short diffusion paths, respectively. This is in qualitatively good agreement with simulated results obtained from a theoretical model based on a combination of the rate equation and diffusion equation.

  10. Single-dimensional currents of a polarizable or magnetizable ideal gas

    Energy Technology Data Exchange (ETDEWEB)

    Gorskii, V.B.

    1977-01-01

    A study is made of one-dimensional, smooth non-dissipative currents in a stream tube of an electrically polarizable or magnetizable ideal gas where electrical and magnetic permeability depend on its density and temperature. A generalized Bernoulli equation was found for these flows as well as a differential relationship (a version of the inverse action law) which determines the conditions for the acceleration and continuous flow transfer through the speed of sound. Certain individual cases of those flows as well as a differential relationship (a version of the inverse action law) which determines the conditions for the acceleration and continuous flow transfer through the speed of sound. Certain individual cases of those flows are examined. 7 references.

  11. Energy distribution of metal and noble gas ions traversing single-crystal copper films

    Science.gov (United States)

    Isakhanov, Z. A.

    2012-09-01

    A comparative investigation of the energy distribution of ions that traversed single-crystal cooper films reveals that the energy loss of channeled and nonchanneled particles depends not only on the mass but also on the radius of bombarding ions. It is established that the energy spectra of transmitted ions are highly sensitive to a change in the composition and structure of the films. From the change in these spectra, one can estimate the degree of disordering in thin films under various applied forces.

  12. Spatial distribution of particles sputtered from single crystals by gas cluster ions

    Science.gov (United States)

    Nazarov, A. V.; Chernysh, V. S.; Nordlund, K.; Djurabekova, F.; Zhao, J.

    2017-09-01

    The results of molecular dynamics simulations of the bombardment of the Cu (100) and Mo (100) single-crystals by 10 keV Ar cluster ions of different sizes are presented in this paper. Spatial distributions of sputtered material were calculated. The anisotropy of the angular distributions of sputtered atoms was revealed. It was found that the character of the anisotropy is different for Cu and Mo targets. The reasons leading to this anisotropy are discussed according to the dependences of the angular distributions on the cluster size and on the target material.

  13. Space Systems - Safety and Compatibility of Materials - Method to Determine the Flammability Thresholds of Materials

    Science.gov (United States)

    Hirsch, David

    2009-01-01

    Spacecraft fire safety emphasizes fire prevention, which is achieved primarily through the use of fire-resistant materials. Materials selection for spacecraft is based on conventional flammability acceptance tests, along with prescribed quantity limitations and configuration control for items that are non-pass or questionable. ISO 14624-1 and -2 are the major methods used to evaluate flammability of polymeric materials intended for use in the habitable environments of spacecraft. The methods are upward flame-propagation tests initiated in static environments and using a well-defined igniter flame at the bottom of the sample. The tests are conducted in the most severe flaming combustion environment expected in the spacecraft. The pass/fail test logic of ISO 14624-1 and -2 does not allow a quantitative comparison with reduced gravity or microgravity test results; therefore their use is limited, and possibilities for in-depth theoretical analyses and realistic estimates of spacecraft fire extinguishment requirements are practically eliminated. To better understand the applicability of laboratory test data to actual spacecraft environments, a modified ISO 14624 protocol has been proposed that, as an alternative to qualifying materials as pass/fail in the worst-expected environments, measures the actual upward flammability limit for the material. A working group established by NASA to provide recommendations for exploration spacecraft internal atmospheres realized the importance of correlating laboratory data with real-life environments and recommended NASA to develop a flammability threshold test method. The working group indicated that for the Constellation Program, the flammability threshold information will allow NASA to identify materials with increased flammability risk from oxygen concentration and total pressure changes, minimize potential impacts, and allow for development of sound requirements for new spacecraft and extravehicular landers and habitats

  14. Modelling leaf, plant and stand flammability for ecological and operational decision making

    Science.gov (United States)

    Zylstra, Philip

    2014-05-01

    Numerous factors have been found to affect the flammability of individual leaves and plant parts; however the way in which these factors relate to whole plant flammability, fire behaviour and the overall risk imposed by fire is not straightforward. Similarly, although the structure of plant communities is known to affect the flammability of the stand, a quantified, broadly applicable link has proven difficult to establish and validate. These knowledge gaps have presented major obstacles to the integration into fire behaviour science of research into factors affecting plant flammability, physiology, species succession and structural change, so that the management of ecosystems for fire risk is largely uninformed by these fields. The Forest Flammability Model (Zylstra, 2011) is a process-driven, complex systems model developed specifically to address this disconnect. Flame dimensions and position are calculated as properties emerging from the capacity for convective heat to propagate flame between horizontally and vertically separated leaves, branches, plants and plant strata, and this capacity is determined dynamically from the ignitability, combustibility and sustainability of those objects, their spatial arrangement and a vector-based model of the plume temperature from each burning fuel. All flammability properties as well as the physics of flame dimensions, angle and temperature distributions and the vertical structure of wind within the plant array use published sub-models which can be replaced as further work is developed. This modular structure provides a platform for the immediate application of new work on any aspect of leaf flammability or fire physics. Initial validation of the model examined its qualitative predictions for trends in forest flammability as a function of time since fire. The positive feedback predicted for the subalpine forest examined constituted a 'risky prediction' by running counter to the expectations of the existing approach, however

  15. Elution parameters in constant-pressure, single-ramp temperature-programmed gas chromatography.

    Science.gov (United States)

    Blumberg, L M; Klee, M S

    2001-05-18

    The dependence of the degree of interaction of a solute with the stationary phase at the time of its elution from the column in temperature-programmed GC is best described by interaction level of the solute. The latter represents the fraction of a solute residing in the stationary phase relative to the total amount of the solute. A simple approach to the evaluation of interaction levels of eluting solutes in a single-ramp temperature program is proposed. In a single-ramp temperature program having no preceding temperature plateau, all solutes that elute at temperatures that are about 60 degrees C higher than the initial temperature of the heating ramp elute with nearly the same interaction levels that can be found as exp(-r), where r is dimensionless heating rate. A specially designed temperature plateau preceding the ramp causes all solutes eluting during the entire time of the ramp to elute with nearly the same interaction levels equal to exp(-r). A transformation of the interaction level of a solute into its retention factor or mobility factor (a fraction of a solute in a mobile phase in relation to the total amount of the solute) and vice versa is also described.

  16. The 1257 Samalas eruption (Lombok, Indonesia): the single greatest stratospheric gas release of the Common Era

    Science.gov (United States)

    Vidal, Céline M.; Métrich, Nicole; Komorowski, Jean-Christophe; Pratomo, Indyo; Michel, Agnès; Kartadinata, Nugraha; Robert, Vincent; Lavigne, Franck

    2016-10-01

    Large explosive eruptions inject volcanic gases and fine ash to stratospheric altitudes, contributing to global cooling at the Earth’s surface and occasionally to ozone depletion. The modelling of the climate response to these strong injections of volatiles commonly relies on ice-core records of volcanic sulphate aerosols. Here we use an independent geochemical approach which demonstrates that the great 1257 eruption of Samalas (Lombok, Indonesia) released enough sulphur and halogen gases into the stratosphere to produce the reported global cooling during the second half of the 13th century, as well as potential substantial ozone destruction. Major, trace and volatile element compositions of eruptive products recording the magmatic differentiation processes leading to the 1257 eruption indicate that Mt Samalas released 158 ± 12 Tg of sulphur dioxide, 227 ± 18 Tg of chlorine and a maximum of 1.3 ± 0.3 Tg of bromine. These emissions stand as the greatest volcanogenic gas injection of the Common Era. Our findings not only provide robust constraints for the modelling of the combined impact of sulphur and halogens on stratosphere chemistry of the largest eruption of the last millennium, but also develop a methodology to better quantify the degassing budgets of explosive eruptions of all magnitudes.

  17. The 1257 Samalas eruption (Lombok, Indonesia): the single greatest stratospheric gas release of the Common Era

    Science.gov (United States)

    Vidal, Céline M.; Métrich, Nicole; Komorowski, Jean-Christophe; Pratomo, Indyo; Michel, Agnès; Kartadinata, Nugraha; Robert, Vincent; Lavigne, Franck

    2016-01-01

    Large explosive eruptions inject volcanic gases and fine ash to stratospheric altitudes, contributing to global cooling at the Earth’s surface and occasionally to ozone depletion. The modelling of the climate response to these strong injections of volatiles commonly relies on ice-core records of volcanic sulphate aerosols. Here we use an independent geochemical approach which demonstrates that the great 1257 eruption of Samalas (Lombok, Indonesia) released enough sulphur and halogen gases into the stratosphere to produce the reported global cooling during the second half of the 13th century, as well as potential substantial ozone destruction. Major, trace and volatile element compositions of eruptive products recording the magmatic differentiation processes leading to the 1257 eruption indicate that Mt Samalas released 158 ± 12 Tg of sulphur dioxide, 227 ± 18 Tg of chlorine and a maximum of 1.3 ± 0.3 Tg of bromine. These emissions stand as the greatest volcanogenic gas injection of the Common Era. Our findings not only provide robust constraints for the modelling of the combined impact of sulphur and halogens on stratosphere chemistry of the largest eruption of the last millennium, but also develop a methodology to better quantify the degassing budgets of explosive eruptions of all magnitudes. PMID:27721477

  18. The 1257 Samalas eruption (Lombok, Indonesia): the single greatest stratospheric gas release of the Common Era.

    Science.gov (United States)

    Vidal, Céline M; Métrich, Nicole; Komorowski, Jean-Christophe; Pratomo, Indyo; Michel, Agnès; Kartadinata, Nugraha; Robert, Vincent; Lavigne, Franck

    2016-10-10

    Large explosive eruptions inject volcanic gases and fine ash to stratospheric altitudes, contributing to global cooling at the Earth's surface and occasionally to ozone depletion. The modelling of the climate response to these strong injections of volatiles commonly relies on ice-core records of volcanic sulphate aerosols. Here we use an independent geochemical approach which demonstrates that the great 1257 eruption of Samalas (Lombok, Indonesia) released enough sulphur and halogen gases into the stratosphere to produce the reported global cooling during the second half of the 13th century, as well as potential substantial ozone destruction. Major, trace and volatile element compositions of eruptive products recording the magmatic differentiation processes leading to the 1257 eruption indicate that Mt Samalas released 158 ± 12 Tg of sulphur dioxide, 227 ± 18 Tg of chlorine and a maximum of 1.3 ± 0.3 Tg of bromine. These emissions stand as the greatest volcanogenic gas injection of the Common Era. Our findings not only provide robust constraints for the modelling of the combined impact of sulphur and halogens on stratosphere chemistry of the largest eruption of the last millennium, but also develop a methodology to better quantify the degassing budgets of explosive eruptions of all magnitudes.

  19. Flammability of tree species for use in fuelbreaks at forest fires prevention

    Directory of Open Access Journals (Sweden)

    Bruna Kovalsyki

    2017-01-01

    Full Text Available Among several silvicultural measures of forest fires prevention, fuelbreaks stands out. These structures are used to reduce and/or prevent fire spread. They consist of plantations with lower flammability species than the main species. The aim of this study was to evaluate the flammability of Psidium cattleianum Sabine., Ligustrum lucidum W. T. Aiton., Schinus terebinthifolius Raddi. and Bougainvillea glabra Choisy, for potential use in fuelbreaks. In this research Pinus taeda L. was used as control. Samples consisted of 1 g of fine material (< 0.7 cm of diameter newly collected. Samples burning were performed in epiradiator, under temperature between 250 °C and 350 °C. It was carried out 50 replications for each species. It was analyzed ignition frequency, time to ignition, combustion duration, combustion index, and it was also determined flammability value. P. taeda presents a very high combustion intensity and was classified as a flammable species. The other species were considered poorly flammable. S. terebinthifolius and B. glabra indicated low combustion intensity, L. lucidum medium and P. cattleianum high combustion intensity. In this context, it was concluded that these species have potential to be used in fuelbreaks to prevent forest fires.

  20. Operational Considerations for Oxygen Flammability Risks: Concentrated Oxygen Diffusion and Permeation Behaviors

    Science.gov (United States)

    Harper, Susana; Smith, Sarah; Juarez, Alfredo; Hirsch, David

    2010-01-01

    Increased human spaceflight operations utilize oxygen concentrations that are frequently varied with use of concentrations up to 100 percent oxygen. Even after exiting a higher percentage oxygen environment, high oxygen concentrations can still be maintained due to material saturation and oxygen entrapment between barrier materials. This paper examines the material flammability concerns that arise from changing oxygen environments during spaceflight operations. We examine the time required for common spacecraft and spacesuit materials exposed to oxygen to return to reduced ignitability and flammability once removed from the increased concentration. Various common spacecraft materials were considered: spacecraft cabin environment foams, Extra Vehicular Mobility Unit materials and foams, Advanced Crew Escape Suit materials, and other materials of interest such as Cotton, Nomex^ HT90-40, and Tiburon Surgical Drape. This paper presents calculated diffusion coefficients derived from experimentally obtained oxygen transmission rates for the tested materials and the analytically derived times necessary for reduced flammability to be achieved based on NASA flammability criteria. Oxygen material saturation and entrapment scenarios are examined. Experimental verification data on oxygen diffusion in saturation scenarios are also presented and discussed. We examine how to use obtained data to address flammability concerns during operational planning to reduce the likelihood of fires while improving efficiency for procedures.

  1. Wire Insulation Flammability Experiment: USML-1 One Year Post Mission Summary

    Science.gov (United States)

    Greenberg, Paul S.; Sacksteder, Kurt R.; Kashiwagi, Takashi

    1994-01-01

    Herein we report the results from the Wire Insulation Flammability (WIF) Experiment performed in the Glovebox Facility on the USML-1 mission. This experiment explored various aspects of electrically induced fire scenarios in a reduced gravity environment. Under quiescent microgravity conditions, heat and mass transfer are dominated by diffusive and radiative transport; while in normal-gravity buoyancy induced convection often dominates. Of considerable scientific and practical interest is the intermediate situation of combustion occurring in the presence of imposed gas flows, with lower characteristic velocities than those induced by buoyancy in noma1 gravity. Two distinct cases naturally arise: flow direction opposed to, or concurrent with, the flame spread direction. Two tests of each kind were conducted in the WIF experiment, providing the first controlled demonstration of flame spreading in forced convection ever conducted in space. Four test modules were flown. The wire insulation, 1.5 mm in diameter, was polyethylene, extruded onto nichrome wire. Temperatures of the wh3 cores and insulation heated in quiescent and flowing environments were measured. Video and still-camera images of the samples, burning in air flowing at approximately 10 cm/sec, were recorded to obtain flame characteristics including spread rate, structure and temperature. Flame spread rates in concurrent flow were approximately twice those in opposed flow. In concurrent and opposed flow regimes, the spreading flames stabilized around a bead of molten insulation material, within which bubble nucleation was observed. An ignition attempt without flow mated a quiescent cloud of vaporized fuel which ignited dramatically yet failed to sustain normal flame spread. Finally, all tests produced substantial soot agglomerates, particularly the concurrent flow tests; and the collected soot has a morphology very distinct from soot formed in normal gravity flames. Several unexpected and unique microgravity

  2. Environmental Stress Testing of the Single Sample Cylinder: A Proven Consensus Standard for Internal Gas Analysis (IGA) or Residual Gas Analysis (RGA)

    Science.gov (United States)

    Schuessler, Philipp WH

    2010-01-01

    In August 2008, Schuessler Consulting was contracted by NASA GSFC in support of the NASA Electronic Parts and Packaging (NEPP) program to perform two separate studies on moisture laden air in a stainless steel cylinder that had been designed to become a consensus standard for Test Method 1018. This Test Method was originally released for hybrids under Mil. Std. 883 but was quickly utilized on other microelectronic devices under the auspice of Mil. Std. 750. The cylinder had subsequently been fabricated for the 750 community. It was back-filled with moist air and subsequently analyzed over a period of time under a previous NASA contract. It had been shown that moisture in the 4000 - 5000 ppm range could be analyzed rather precisely with a mass spectrometer, commonly referred to as a Residual Gas Analyzer (RGA). The scope of this study was to ascertain if the composition and precision varied as a function of thermal shock at sub-zero temperatures and whether there was consensus when the standard was submitted to other RGA units. It was demonstrated and published that the consensus standard would yield precise RGA data for moisture within +/- 1% when optimized for a given RGA unit. It has been subsequently shown in this study at Oneida Research Services, that sub-zero storage did not affect that precision when a well-defined protocol for the analysis was followed. The consensus standard was taken to a second facility for analysis where it was found that moisture adsorption on the transfer lines caused precision to drop to +/- 12%. The Single Sample Cylinder (SSC) is a one liter stainless steel cylinder with associated sampling valves and has considerable weight and volume. But this considerable size allows for approximately 300 gas samples of the same composition to be delivered to any RGA unit. Lastly, a smaller cylinder, approximately 75 cc, of a second consensus standard was fabricated and tested with a different mix of fixed gases where moisture was kept in the

  3. Krypton Gas for High Quality Single Wall Carbon Nanotubes Synthesis by KrF Excimer Laser Ablation

    Directory of Open Access Journals (Sweden)

    Jasim Al-Zanganawee

    2015-01-01

    Full Text Available We report for the first time the production of single wall carbon nanotubes (SWCNTs by KrF excimer laser ablation method under the krypton gas atmosphere. For the ablation experiment 450 mJ energy and 30 Hz repetition rate KrF excimer laser was used, and the target was prepared with the following composition: 0.6% Ni, 0.6% Co, and 98.8% C (atomic percentage. The ablation product was characterized by confocal Raman microspectroscopy, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and thermogravimetric analysis (TGA. The SWCNTs obtained are a mixture of semiconducting and metallic types with narrow diameters distribution of 1.26 to 1.49 nm, are micrometers long, and contain low amount of graphite and amorphous carbon.

  4. Taguchi Based Regression Analysis of End-Wall Film Cooling in a Gas Turbine Cascade with Single Row of Holes

    Science.gov (United States)

    Ravi, D.; Parammasivam, K. M.

    2016-09-01

    Numerical investigations were conducted on a turbine cascade, with end-wall cooling by a single row of cylindrical holes, inclined at 30°. The mainstream fluid was hot air and the coolant was CO2 gas. Based on the Reynolds number, the flow was turbulent at the inlet. The film hole row position, its pitch and blowing ratio was varied with five different values. Taguchi approach was used in designing a L25 orthogonal array (OA) for these parameters. The end-wall averaged film cooling effectiveness (bar η) was chosen as the quality characteristic. CFD analyses were carried out using Ansys Fluent on computational domains designed with inputs from OA. Experiments were conducted for one chosen OA configuration and the computational results were found to correlate well with experimental measurements. The responses from the CFD analyses were fed to the statistical tool to develop a correlation for bar η using regression analysis.

  5. Design of Accumulators and Liquid/Gas Charging of Single Phase Mechanically Pumped Fluid Loop Heat Rejection Systems

    Science.gov (United States)

    Bhandari, Pradeep; Dudik, Brenda; Birur, Gajanana; Karlmann, Paul; Bame, David; Mastropietro, A. J.

    2012-01-01

    For single phase mechanically pumped fluid loops used for thermal control of spacecraft, a gas charged accumulator is typically used to modulate pressures within the loop. This is needed to accommodate changes in the working fluid volume due to changes in the operating temperatures as the spacecraft encounters varying thermal environments during its mission. Overall, the three key requirements on the accumulator to maintain an appropriate pressure range throughout the mission are: accommodation of the volume change of the fluid due to temperature changes, avoidance of pump cavitation and prevention of boiling in the liquid. The sizing and design of such an accumulator requires very careful and accurate accounting of temperature distribution within each element of the working fluid for the entire range of conditions expected, accurate knowledge of volume of each fluid element, assessment of corresponding pressures needed to avoid boiling in the liquid, as well as the pressures needed to avoid cavitation in the pump. The appropriate liquid and accumulator strokes required to accommodate the liquid volume change, as well as the appropriate gas volumes, require proper sizing to ensure that the correct pressure range is maintained during the mission. Additionally, a very careful assessment of the process for charging both the gas side and the liquid side of the accumulator is required to properly position the bellows and pressurize the system to a level commensurate with requirements. To achieve the accurate sizing of the accumulator and the charging of the system, sophisticated EXCEL based spreadsheets were developed to rapidly come up with an accumulator design and the corresponding charging parameters. These spreadsheets have proven to be computationally fast and accurate tools for this purpose. This paper will describe the entire process of designing and charging the system, using a case study of the Mars Science Laboratory (MSL) fluid loops, which is en route to

  6. Magnetoelectronic transport of the two-dimensional electron gas in CdSe single quantum wells

    Indian Academy of Sciences (India)

    P K Ghosh; A Ghosal; D Chattopadhyay

    2009-02-01

    Hall mobility and magnetoresistance coefficient for the two-dimensional (2D) electron transport parallel to the heterojunction interfaces in a single quantum well of CdSe are calculated with a numerical iterative technique in the framework of Fermi–Dirac statistics. Lattice scatterings due to polar-mode longitudinal optic (LO) phonons, and acoustic phonons via deformation potential and piezoelectric couplings, are considered together with background and remote ionized impurity interactions. The parallel mode of piezoelectric scattering is found to contribute more than the perpendicular mode. We observe that the Hall mobility decreases with increasing temperature but increases with increasing channel width. The magnetoresistance coefficient is found to decrease with increasing temperature and increase with increasing magnetic field in the classical region.

  7. Experimental and theoretical comparison of gas desorption energies on metallic and semiconducting single-walled carbon nanotubes.

    Science.gov (United States)

    Mandeltort, Lynn; Chen, De-Li; Saidi, Wissam A; Johnson, J Karl; Cole, Milton W; Yates, John T

    2013-05-22

    Single-walled carbon nanotubes (SWNTs) exhibit high surface areas and precisely defined pores, making them potentially useful materials for gas adsorption and purification. A thorough understanding of the interactions between adsorbates and SWNTs is therefore critical to predicting adsorption isotherms and selectivities. Metallic (M-) and semiconducting (S-) SWNTs have extremely different polarizabilities that might be expected to significantly affect the adsorption energies of molecules. We experimentally and theoretically show that this expectation is contradicted, for both a long chain molecule (n-heptane) and atoms (Ar, Kr, and Xe). Temperature-programmed desorption experiments are combined with van der Waals corrected density functional theory, examining adsorption on interior and exterior sites of the SWNTs. Our calculations show a clear dependence of the adsorption energy on nanotube diameter but not on whether the tubes are conducting or insulating. We find no significant experimental or theoretical difference in adsorption energies for molecules adsorbed on M- and S-SWNTs having the same diameter. Hence, we conclude that the differences in polarizabilities between M- and S-SWNTs have a negligible influence on gas adsorption for spherical molecules as well as for highly anisotropic molecules such as n-heptane. We expect this conclusion to apply to all types of adsorbed molecules where van der Waals interactions govern the molecular interaction with the SWNT.

  8. Modeling and validation of single-chamber microbial fuel cell cathode biofilm growth and response to oxidant gas composition

    Science.gov (United States)

    Ou, Shiqi; Zhao, Yi; Aaron, Douglas S.; Regan, John M.; Mench, Matthew M.

    2016-10-01

    This work describes experiments and computational simulations to analyze single-chamber, air-cathode microbial fuel cell (MFC) performance and cathodic limitations in terms of current generation, power output, mass transport, biomass competition, and biofilm growth. Steady-state and transient cathode models were developed and experimentally validated. Two cathode gas mixtures were used to explore oxygen transport in the cathode: the MFCs exposed to a helium-oxygen mixture (heliox) produced higher current and power output than the group of MFCs exposed to air or a nitrogen-oxygen mixture (nitrox), indicating a dependence on gas-phase transport in the cathode. Multi-substance transport, biological reactions, and electrochemical reactions in a multi-layer and multi-biomass cathode biofilm were also simulated in a transient model. The transient model described biofilm growth over 15 days while providing insight into mass transport and cathodic dissolved species concentration profiles during biofilm growth. Simulation results predict that the dissolved oxygen content and diffusion in the cathode are key parameters affecting the power output of the air-cathode MFC system, with greater oxygen content in the cathode resulting in increased power output and fully-matured biomass.

  9. Detachment of CVD-grown graphene from single crystalline Ni films by a pure gas phase reaction

    Science.gov (United States)

    Zeller, Patrick; Henß, Ann-Kathrin; Weinl, Michael; Diehl, Leo; Keefer, Daniel; Lippmann, Judith; Schulz, Anne; Kraus, Jürgen; Schreck, Matthias; Wintterlin, Joost

    2016-11-01

    Despite great previous efforts there is still a high need for a simple, clean, and upscalable method for detaching epitaxial graphene from the metal support on which it was grown. We present a method based on a pure gas phase reaction that is free of solvents and polymer supports and avoids mechanical transfer steps. The graphene was grown on 150 nm thick, single crystalline Ni(111) films on Si(111) wafers with YSZ buffer layers. Its quality was monitored by using low energy electron diffraction and scanning tunneling microscopy. The gas phase etching uses a chemical transport reaction, the so-called Mond process, based on the formation of gaseous nickel tetracarbonyl in ~ 1 bar of CO at ~ 75 °C and by adding small amounts of sulfide catalysts. X-ray photoelectron spectroscopy, Raman spectroscopy and scanning electron microscopy were used to characterize the detached graphene. It was found that the method successfully removes the nickel from underneath the graphene layer, so that the graphene lies on the insulating oxide buffer layer. Small residual particles of nickel sulfide and cracks in the obtained graphene layer were identified. The defect concentrations were comparable to graphene samples obtained by wet chemical etching and by the bubbling transfer.

  10. Applied reaction dynamics: Efficient synthesis gas production via single collision partial oxidation of methane to CO on Rh(111)

    Science.gov (United States)

    Gibson, K. D.; Viste, M.; Sibener, S. J.

    2006-10-01

    Supersonic molecular beams have been used to determine the yield of CO from the partial oxidation of CH4 on a Rh(111) catalytic substrate, CH4+(1/2)O2→CO +2H2, as a function of beam kinetic energy. These experiments were done under ultrahigh vacuum conditions with concurrent molecular beams of O2 and CH4, ensuring that there was only a single collision for the CH4 to react with the surface. The fraction of CH4 converted is strongly dependent on the normal component of the incident beam's translational energy, and approaches unity for energies greater than ˜1.3eV. Comparison with a simplified model of the methane-Rh(111) reactive potential gives insight into the barrier for methane dissociation. These results demonstrate the efficient conversion of methane to synthesis gas, CO +2H2, are of interest in hydrogen generation, and have the optimal stoichiometry for subsequent utilization in synthetic fuel production (Fischer-Tropsch or methanol synthesis). Moreover, under the reaction conditions explored, no CO2 was detected, i.e., the reaction proceeded with the production of very little, if any, unwanted greenhouse gas by-products. These findings demonstrate the efficacy of overcoming the limitations of purely thermal reaction mechanisms by coupling nonthermal mechanistic steps, leading to efficient C-H bond activation with subsequent thermal heterogeneous reactions.

  11. AN INVESTIGATION INTO THE MECHANICS OF SINGLE CRYSTAL TURBINE BLADES WITH A VIEW TOWARDS ENHANCING GAS TURBINE EFFICIENCY

    Energy Technology Data Exchange (ETDEWEB)

    K.R. Rajagopal; I.J. Rao

    2006-05-05

    The demand for increased efficiency of gas turbines used in power generation and aircraft applications has fueled research into advanced materials for gas turbine blades that can withstand higher temperatures in that they have excellent resistance to creep. The term ''Superalloys'' describes a group of alloys developed for applications that require high performance at elevated temperatures. Superalloys have a load bearing capacity up to 0.9 times their melting temperature. The objective of the investigation was to develop a thermodynamic model that can be used to describe the response of single crystal superalloys that takes into account the microstructure of the alloy within the context of a continuum model. Having developed the model, its efficacy was to be tested by corroborating the predictions of the model with available experimental data. Such a model was developed and it is implemented in the finite element software ABAQUS/STANDARD through a user subroutine (UMAT) so that the model can be used in realistic geometries that correspond to turbine blades.

  12. Single-walled carbon nanotubes as stationary phase in gas chromatographic separation and determination of argon, carbon dioxide and hydrogen.

    Science.gov (United States)

    Safavi, Afsaneh; Maleki, Norooz; Doroodmand, Mohammad Mahdi

    2010-08-24

    A chromatographic technique is introduced based on single-walled carbon nanotubes (SWCNTs) as stationary phase for separation of Ar, CO(2) and H(2) at parts per million (ppm) levels. The efficiency of SWCNTs was compared with solid materials such as molecular sieve, charcoal, multi-walled carbon nanotubes and carbon nanofibers. The morphology of SWCNTs was optimized for maximum adsorption of H(2), CO(2) and Ar and minimum adsorption of gases such as N(2), O(2), CO and H(2)O vapour. To control temperature of the gas chromatography column, peltier cooler was used. Mixtures of Ar, CO(2) and H(2) were separated according to column temperature program. Relative standard deviation for nine replicate analyses of 0.2 mL H(2) containing 10 microL of each Ar or CO(2) was 2.5% for Ar, 2.8% for CO(2) and 3.6% for H(2). The interfering effects of CO, and O(2) were investigated. Working ranges were evaluated as 40-600 ppm for Ar, 30-850 ppm for CO(2) and 10-1200 ppm for H(2). Significant sensitivity, small relative standard deviation (RSD) and acceptable limit of detection (LOD) were obtained for each analyte, showing capability of SWCNTs for gas separation and determination processes. Finally, the method was used to evaluate the contents of CO(2) in air sample.

  13. Impregnation of Catalytic Metals in Single-Walled Carbon Nanotubes for Toxic Gas Conversion in Life Support System

    Science.gov (United States)

    Li, Jing; Wignarajah, Kanapathipillai; Cinke, Marty; Partridge, Harry; Fisher, John

    2004-01-01

    Carbon nanotubes (CNTs) possess extraordinary properties such as high surface area, ordered chemical structure that allows functionalization, larger pore volume, and very narrow pore size distribution that have attracted considerable research attention from around the world since their discovery in 1991. The development and characterization of an original and innovative approach for the control and elimination of gaseous toxins using single walled carbon nanotubes (SWNTs) promise superior performance over conventional approaches due to the ability to direct the selective uptake of gaseous species based on their controlled pore size, increased adsorptive capacity due to their increased surface area and the effectiveness of carbon nanotubes as catalyst supports for gaseous conversion. We present our recent investigation of using SWNTs as catalytic supporting materials to impregnate metals, such as rhodium (Rh), palladium (Pd) and other catalysts. A protocol has been developed to oxidize the SWNTs first and then impregnate the Rh in aqueous rhodium chloride solution, according to unique surface properties of SWNTs. The Rh has been successfully impregnated in SWNTs. The Rh-SWNTs have been characterized by various techniques, such as TGA, XPS, TEM, and FTIR. The project is funded by a NASA Research Announcement Grant to find applications of single walled nanocarbons in eliminating toxic gas Contaminant in life support system. This knowledge will be utilized in the development of a prototype SWNT KO, gas purification system that would represent a significant step in the development of high efficiency systems capable of selectively removing specific gaseous for use in regenerative life support system for human exploration missions.

  14. Impregnation of Catalytic Metals in Single-Walled Carbon Nanotubes for Toxic Gas Conversion in Life Support System

    Science.gov (United States)

    Li, Jing; Wignarajah, Kanapathipillai; Cinke, Marty; Partridge, Harry; Fisher, John

    2004-01-01

    Carbon nanotubes (CNTs) possess extraordinary properties such as high surface area, ordered chemical structure that allows functionalization, larger pore volume, and very narrow pore size distribution that have attracted considerable research attention from around the world since their discovery in 1991. The development and characterization of an original and innovative approach for the control and elimination of gaseous toxins using single walled carbon nanotubes (SWNTs) promise superior performance over conventional approaches due to the ability to direct the selective uptake of gaseous species based on their controlled pore size, increased adsorptive capacity due to their increased surface area and the effectiveness of carbon nanotubes as catalyst supports for gaseous conversion. We present our recent investigation of using SWNTs as catalytic supporting materials to impregnate metals, such as rhodium (Rh), palladium (Pd) and other catalysts. A protocol has been developed to oxidize the SWNTs first and then impregnate the Rh in aqueous rhodium chloride solution, according to unique surface properties of SWNTs. The Rh has been successfully impregnated in SWNTs. The Rh-SWNTs have been characterized by various techniques, such as TGA, XPS, TEM, and FTIR. The project is funded by a NASA Research Announcement Grant to find applications of single walled nanocarbons in eliminating toxic gas Contaminant in life support system. This knowledge will be utilized in the development of a prototype SWNT KO, gas purification system that would represent a significant step in the development of high efficiency systems capable of selectively removing specific gaseous for use in regenerative life support system for human exploration missions.

  15. Origin of natural gas; Tennen gas no kigen

    Energy Technology Data Exchange (ETDEWEB)

    Katayama, Y. [The Institute of Applied Energy, Tokyo (Japan)

    1996-03-20

    Natural gas, which is a general term of flammable hydrocarbon gases such as methane, is classified by origin into the following categories : (1) oil field gas (oil gas), (2) aquifers (bacteria-fermented methane), (3) coal gas (coal field gas), and (4) abiogenetic gas. The natural gas which has (1-4) origins and is now used as resource in a large quantity is (1) oil field gas. This gas is a hydrocarbon gas recovered in the production process of petroleum and contains components such as ethane, propane and butane. To the contrary, (2) aquifers and (3) coal gas have methane as main component. As (4) abiogenetic methane, there are gas formed in inorganic reaction in activities of submarine volcanos and deep gas (earth origin gas). Oil field gas has kerogen origin. Aquifers were formed by fermentation of organic matters. Coal gas was formed by coalification of vitrinite. As abiogenetic methane, there are inorganic reaction formation gas and deep gas, the latter of which exists little as resource. 7 refs., 11 figs., 1 tab.

  16. The natural gas industry within the Single Market. Contributions towards the EC legal and administrative discussion on market organization, common carriage and price transparency. Die Gaswirtschaft im Binnenmarkt. Beitraege zur gemeinschaftsrechtlichen und ordnungspolitischen Diskussion von Marktordnungen, Common Carriage und Preistransparenz

    Energy Technology Data Exchange (ETDEWEB)

    Mestmaecker, E.J. (Max-Planck-Institut fuer Auslaendisches und Internationales Privatrecht, Hamburg (Germany, F.R.)); Groener, H. (Bayreuth Univ. (Germany, F.R.). Lehrstuhl fuer Volkswirtschaftslehre 1); Basedow, J. (Augsburg Univ. (Germany, F.R.). Lehrstuhl fuer Buergerliches Recht, Rechtsvergleichung, Internationales Privat-, Prozess- und Wirtschaftsrecht)

    1990-01-01

    The document contains three contributions: 1. Natural gas within the European Single Market; 2. The realization of the EC Single Market for the pipebound power industry: Comparison of electric power industry and natural gas supply, and 3. Natural gas transports within European traffic law. (UA).

  17. Comparison of dilution effects of R134a and nitrogen on flammable hydrofluorocarbons

    Institute of Scientific and Technical Information of China (English)

    Zhenming Li; Maoqiong Gong; Jianfeng Wu; Yuan Zhou

    2009-01-01

    An experimental apparatus has been built to measure the flammability limits of combustible gases based on Chi-nese national standard GB/T 12474-90. The flammability limits of four binary mixtures of R161/R134a, Ri52a/R134a, RI61/N2 and RI52a/N2 were measured with this apparatus at atmospheric pressure and ambient temperature. The fuel inertization points (FIP) of these mixtures can be found from the envelopes. Comparisons were made with the literature data; good agreement for most measurements was obtained. R134a was found to have a better dilution effect than nitrogen in reducing the flammability of hydrofluorocarbons.

  18. Low-energy electron irradiation of preheated and gas-exposed single-wall carbon nanotubes

    Science.gov (United States)

    Ecton, P. A.; Beatty, J.; Verbeck, G.; Lakshantha, W.; Rout, B.; Perez, J. M.

    2016-11-01

    We investigate the conditions under which electron irradiation at 2 keV of single-wall carbon nanotube (SWCNT) bundles produces an increase in the Raman D peak. We find that irradiation of SWCNTs that are preheated in situ at 600 °C for 1 h in ultrahigh vacuum before irradiation does not result in an increase in the D peak. Irradiation of SWCNTs that are preheated in vacuum and then exposed to air or gases results in an increase in the D peak, suggesting that adsorbates play a role in the increase in the D peak. Small diameter SWCNTs that are not preheated or preheated and then exposed to air show a significant increase in the D and G bands after irradiation. X-ray photoelectron spectroscopy shows no chemical shifts in the C 1s peak of SWCNTs that have been irradiated versus SWCNTs that have not been irradiated, suggesting that chemisorption of adsorbates is not responsible for the increase in the D peak.

  19. Low-energy electron irradiation of preheated and gas-exposed single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ecton, P.A. [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Beatty, J.; Verbeck, G. [Department of Chemistry, University of North Texas, Denton, TX 76203 (United States); Lakshantha, W.; Rout, B. [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Perez, J.M., E-mail: jperez@unt.edu [Department of Physics, University of North Texas, Denton, TX 76203 (United States)

    2016-11-30

    Highlights: • Preheating SWCNTs in situ before irradiation prevents an increase in the D peak. • Preheated SWCNTs exposed to air or gases before irradiation show an increase in D peak. • The increase in D peak is not due to irradiation-induced chemisorption of adsorbates. • The effects are more significant for small diameter SWCNTs. • The increase in D peak is attributed to defects that increase inter-tube interactions. - Abstract: We investigate the conditions under which electron irradiation at 2 keV of single-wall carbon nanotube (SWCNT) bundles produces an increase in the Raman D peak. We find that irradiation of SWCNTs that are preheated in situ at 600 °C for 1 h in ultrahigh vacuum before irradiation does not result in an increase in the D peak. Irradiation of SWCNTs that are preheated in vacuum and then exposed to air or gases results in an increase in the D peak, suggesting that adsorbates play a role in the increase in the D peak. Small diameter SWCNTs that are not preheated or preheated and then exposed to air show a significant increase in the D and G bands after irradiation. X-ray photoelectron spectroscopy shows no chemical shifts in the C 1s peak of SWCNTs that have been irradiated versus SWCNTs that have not been irradiated, suggesting that chemisorption of adsorbates is not responsible for the increase in the D peak.

  20. Adsorbing H₂S onto a single graphene sheet: A possible gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Reshak, A. H., E-mail: maalidph@yahoo.co.uk [New Technologies-Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Auluck, S. [Council of Scientific and Industrial Research-National Physical Laboratory, Dr. K S Krishnan Marg, New Delhi 110012 (India)

    2014-09-14

    The electronic structure of pristine graphene sheet and the resulting structure of adsorbing a single molecule of H₂S on pristine graphene in three different sites (bridge, top, and hollow) are studied using the full potential linearized augmented plane wave method. Our calculations show that the adsorption of H₂S molecule on the bridge site opens up a small direct energy gap of about 0.1 eV at symmetry point M, while adsorption of H₂S on top site opens a gap of 0.3 eV around the symmetry point K. We find that adsorbed H₂S onto the hollow site of pristine graphene sheet causes to push the conduction band minimum and the valence band maximum towards Fermi level resulting in a metallic behavior. Comparing the angular momentum decomposition of the atoms projected electronic density of states of pristine graphene sheet with that of H₂S–graphene for three different cases, we find a significant influence of the location of the H₂S molecule on the electronic properties especially the strong hybridization between H₂S molecule and graphene sheet.

  1. Processing and Characterization of Flame Retardant Cotton Blend Nonwovens for Soft Furnishings to Meet Federal Flammability Standards

    Science.gov (United States)

    Effective July 1, 2007, it is mandatory that all mattress sets meet the federal flammability standard CFR 1633. It is necessary to impart flame resistance that would provide at least 30 minutes for occupants to escape fire. Changes in the flammability laws are expected on soft furnishings of sleep ...

  2. Assessing and ranking the flammability of some ornamental plant species to select firewise plants for landscaping in WUI (SE France).

    Science.gov (United States)

    Ganteaume, A.; Jappiot, M.; Lampin, C.

    2012-04-01

    The increasing urbanization of Wildland-Urban Interfaces (WUI) as well as the high fire occurrence in these areas requires the assessment and the ranking of the flammability of the ornamental vegetation surrounding houses especially that planted in hedges. Thus, the flammability of seven species, among those most frequently planted in hedges in Provence (South-Eastern France), were studied at particle level and at dead surface fuel level (litters) under laboratory conditions. The flammability parameters (ignition frequency, time-to-ignition, flaming duration) of the very fine particles (live leaves and particles Cupressus sempervirens litter had the highest bulk density and the longest flaming duration but the lowest flame propagation. Pyracantha coccinea litter was the longest to ignite and flame propagation was low but lasted a long time. Hierarchical cluster analysis performed on the flammability parameters of live leaves and of litters ranked the seven species in four distinct clusters from the most flammable (Prunus laurocerasus and Pyracantha coccinea) to the least flammable (Pittosporum tobira and Nerium oleander); the other species displaying two groups of intermediate flammabilities (Phyllostachys sp.- Photinia fraseri and Cupressus sempervirens ). The species with highly flammable characteristics should not be used in hedges planted in WUIs in South-Eastern France.

  3. An Equilibrium-Based Model of Gas Reaction and Detonation

    Energy Technology Data Exchange (ETDEWEB)

    Trowbridge, L.D.

    2000-04-01

    During gaseous diffusion plant operations, conditions leading to the formation of flammable gas mixtures may occasionally arise. Currently, these could consist of the evaporative coolant CFC-114 and fluorinating agents such as F2 and ClF3. Replacement of CFC-114 with a non-ozone-depleting substitute is planned. Consequently, in the future, the substitute coolant must also be considered as a potential fuel in flammable gas mixtures. Two questions of practical interest arise: (1) can a particular mixture sustain and propagate a flame if ignited, and (2) what is the maximum pressure that can be generated by the burning (and possibly exploding) gas mixture, should it ignite? Experimental data on these systems, particularly for the newer coolant candidates, are limited. To assist in answering these questions, a mathematical model was developed to serve as a tool for predicting the potential detonation pressures and for estimating the composition limits of flammability for these systems based on empirical correlations between gas mixture thermodynamics and flammability for known systems. The present model uses the thermodynamic equilibrium to determine the reaction endpoint of a reactive gas mixture and uses detonation theory to estimate an upper bound to the pressure that could be generated upon ignition. The model described and documented in this report is an extended version of related models developed in 1992 and 1999.

  4. Investigation into the conditions under which HFC134a may become flammable.

    CSIR Research Space (South Africa)

    Kramers, AP

    2002-01-01

    Full Text Available flammability limit of a propane/HFC134a/air mixture (Schröeder 1995). The contribution of the lubricant to the flammability of HFC134a was not well understood. The literature review and findings of the Tau Tona accident report (Department of Minerals... are also highly dependent on the type of ignition source and the volume of the vessel used. 2.1.2 Lubricants used with HFC134a Lubricants used with refrigerant 134a are mineral oils; alkyl benzenes; dibasic, polybasic and polyol esters...

  5. Will elevated CO2 alter fuel characteristics and flammability of eucalypt woodlands?

    Science.gov (United States)

    Collins, Luke; Resco, Victor; Boer, Matthias; Bradstock, Ross; Sawyer, Robert

    2016-04-01

    Rising atmospheric CO2 may enhance forest productivity via CO2 fertilisation and increased soil moisture associated with water savings, potentially resulting in increased woody plant abundance i.e. woody thickening. Changes to vegetation structure via woody thickening, as well as changes to vegetation properties (e.g. leaf characteristics and moisture content), may have important implications for ecosystem flammability and fire regimes. Understanding how elevated CO2 alters flammability and fire regimes will have implications for ecosystem dynamics, particularly carbon sequestration and emissions. We present data from Free Air CO2 Enrichment (EucFACE) and whole tree growth chamber (WTC) experiments to assess the effect of elevated CO2 on fuel properties and flammability of eucalypt woodlands. Experiments involved ambient (˜400 ppm) and elevated CO2treatments, with elevated treatments being +150 ppm and +240 ppm at EucFACE and the WTCs respectively. We examined the response of vegetation parameters known to influence ecosystem flammability, namely (i) understorey vegetation characteristics (ii) understorey fuel moisture and (iii) leaf flammability. Understorey growth experiments at EucFACE using seedlings of two common woody species (Hakea sericia, Eucalyptus tereticornis) indicate that elevated CO2 did not influence stem and leaf biomass, height or crown dimensions of seedlings after 12 months exposure to experimental treatments. Temporal changes to understorey live fuel moisture were assessed at EucFACE over an 18 month period using time lapse cameras. Understorey vegetation greenness was measured daily from digital photos using the green chromatic coordinate (GCC), an index that is highly correlated with live fuel moisture (R2 = 0.90). GCC and rates of greening and browning were not affected by elevated CO2, though they were highly responsive to soil moisture availability and temperature. This suggests that there is limited potential for elevated CO2 to alter

  6. Comparative study of all-printed polyimide humidity sensors with single- and multiwalled carbon nanotube gas-permeable top electrodes

    Science.gov (United States)

    Itoh, Eiji; Yuan, Zihan

    2017-05-01

    We have developed printed capacitive humidity sensors with highly gas permeable carbon nanotube top electrodes using solution techniques. The hydrophobic, porous multiwalled carbon nanotube (MWCNT) network was suitable for gas permeation, and the response of the capacitive humidity sensors was faster than that of a device with a single-walled carbon nanotube (SWCNT) top electrode. The newly developed measurement system consisting of a small measurement chamber, a computer-controlled high-speed solenoid valve, and a mass-flow controller enabled us to vary the ambient relative humidity within 0.1 s. A comparative study of the devices consisting of a 1.1-µm-thick partially fluorinated polyimide dielectric layer and an MWCNT or SWCNT top electrode revealed that the rise time (humidification process) of the device with MWCNTs (0.49 s) in the transient measurement was almost 3 times shorter than that with SWCNTs (1.48 s) owing to the hydrophobic surface of the MWCNTs. A much larger difference was observed during the drying process (recovery time) probably owing to the hydrophilic parts of the SWCNT surface. It was revealed that the response time was almost proportional to the square of the thickness of the polyimide dielectric layer, d, and the sensitivity was inversely proportional to d. The rise time decreased to 0.15 s and a sensitivity per unit area of 12.1 pF %RH-1 cm-2 was obtained in a device with 0.6-µm-thick polyimide and MWCNT top electrodes. This value is suitable for use in high-speed humidity sensors to realize a real-time humidity and breath-sensing measurement system.

  7. The vibrational spectra of N-phenylpyrrole in the gas phase, in argon matrices and in single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Schweke, D. [Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Farkas Center for Light-Induced Processes, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Brauer, B. [Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Fritz Haber Research Center, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Gerber, R.B. [Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Fritz Haber Research Center, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Department of Chemistry, University of California, Irvine, CA 92697 (United States); Haas, Y. [Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Farkas Center for Light-Induced Processes, Hebrew University of Jerusalem, Jerusalem 91904 (Israel)], E-mail: yehuda@chem.ch.huji.ac.il

    2007-03-30

    The infrared spectrum of N-phenylpyrrole (PP) was measured in the gas phase and in an argon matrix, and the Raman spectrum was obtained in a single crystal. The measured matrix shifts are found to be small: many bands are not split, and the shifts from the gas phase values are less than 1%. Splitting to two sub-bands is observed for some bands, indicating the presence of two major trapping sites, in agreement with previous predictions. The spectra are analyzed with the help of harmonic calculations on the free molecule and on its adduct with one or two argon atoms, and anharmonic frequency calculations on the free molecule. Harmonic frequencies were obtained at the MP2/cc-pVDZ and DFT-B3LYP/cc-pVDZ levels. Anharmonic frequencies were obtained by the correlation-corrected vibrational self-consistent field (CC-VSCF) method with a variant of the PM3 semiempirical electronic structure method, calibrated for much improved spectroscopic accuracy. The potential surfaces used in the CC-VSCF calculation obtained by adjusting standard PM3 surfaces so that they provide harmonic frequencies that are comparable to those obtained at the DFT-B3LYP/cc-pVDZ level. Agreement between the experimental and theoretical results is in general very good, allowing the assignments of most bands. The harmonic frequency calculations of PP-Ar clusters, at the MP2/cc-pVDZ level show that the environment can greatly affect the intensities of some of the transitions, which is in accord with experiment.

  8. Flammability Analysis For Actinide Oxides Packaged In 9975 Shipping Containers

    Energy Technology Data Exchange (ETDEWEB)

    Laurinat, James E.; Askew, Neal M.; Hensel, Steve J.

    2013-03-21

    Packaging options are evaluated for compliance with safety requirements for shipment of mixed actinide oxides packaged in a 9975 Primary Containment Vessel (PCV). Radiolytic gas generation rates, PCV internal gas pressures, and shipping windows (times to reach unacceptable gas compositions or pressures after closure of the PCV) are calculated for shipment of a 9975 PCV containing a plastic bottle filled with plutonium and uranium oxides with a selected isotopic composition. G-values for radiolytic hydrogen generation from adsorbed moisture are estimated from the results of gas generation tests for plutonium oxide and uranium oxide doped with curium-244. The radiolytic generation of hydrogen from the plastic bottle is calculated using a geometric model for alpha particle deposition in the bottle wall. The temperature of the PCV during shipment is estimated from the results of finite element heat transfer analyses.

  9. Correlation of Flammability Test Data on Antimisting Fuels.

    Science.gov (United States)

    1982-12-01

    studies using filters made of stainless steel meshes, Millipore PTFE membranes and cured aircraft filter papers. 4 The aim of this RAE work was to...The study of Weiss and Worsham 4 5 produced one of the best available sets of droplet data. They employed hot wax in a hot gas stream to avoid effects...potential usefulness in antimisting fuels correlations. An example of a mass-size distribution obtained experimentally for hot wax in a hot gas stream by

  10. Specifications for gas treatment apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Teraoka, Yuden; Yoshigoe, Akitaka [Japan Atomic Energy Research Inst., Kansai Research Establishment, Synchrotron Radiation Research Center, Mikazuki, Hyogo (Japan)

    2001-03-01

    A surface reaction analysis apparatus was installed as an experimental end-station for the study of surface chemistry at the JAERI soft x-ray beamline in the SPring-8. The surface reaction analysis apparatus is devoted to the study of reaction mechanisms on solid surfaces with incident gas molecules. It is necessary to supply reagent gases to the apparatus. Chlorine and metal organic molecules will be used in the apparatus as well as oxygen molecules. Since the chlorine is corrosive and virulent, the metal organic molecules are flammable, the satiety treatments and the removal of virulence from the exhaust gas are needed. This gas supply and exhaust system is mainly composed of a cylinder cabinet, a gas mixer, a virulence removal cell and an urgent virulence removal apparatus. The former three devices are considered to take a countermeasure against virulent gas leak. The detail specifications concerning the gas supply and exhaust system are described in this report. (author)

  11. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  12. Application of noncatalytic gas-solid reactions for a single pellet of changing size to the modeling of fluidized-bed combustion of coal char containing sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Rehmat, A.; Saxena, S.C.; Land, R.H.

    1980-09-01

    A mechanistic model is developed for coal char combustion, with sulfur retention by limestone or dolomite sorbent, in a gas fluidized bed employing noncatalytic single pellet gas-solid reactions. The shrinking core model is employed to describe the kinetics of chemical reactions taking place on a single pellet; changes in pellet size as the reaction proceeds are considered. The solids are assumed to be in back-mix condition whereas the gas flow is regarded to be in plug flow. Most char combustion occurs near the gas distributor plate (at the bottom of the bed), where the bubbles are small and consequently the mass transfer rate is high. For such a case, the analysis is considerably simplified by ignoring the bubble phase since it plays an insignificant role in the overall rate of carbon conversion. Bubble-free operation is also encounterd in the turbulent regime, where the gas flow is quite high and classical bubbles do not exist. Formulation of the model includes setting up heat and mass balance equations pertaining to a single particle (1) exposed to a varying reactant concentration along the height of the bed and (2) whose size changes during reaction. These equations are then solved numerically to account for particles of all sizes in the bed in obtaining the overall carbon conversion efficiency and resultant sulfur retention. In particular, the influence on sorbent requirement of several fluid-bed variables such as oxygen concentration profile, particle size, reaction rate for sulfation reaction, and suflur adsorption efficiency are examined.

  13. Electronic Properties of Boron and Silicon Doped (10, 0 Zigzag Single-Walled Carbon Nanotube upon Gas Molecular Adsorption: A DFT Comparative Study

    Directory of Open Access Journals (Sweden)

    P. A. Gowri sankar

    2013-01-01

    Full Text Available We have performed a comparative study of nine predominant gas molecules (H2, H2O, O2, CO, CO2, NO, NO2, NH3, and CH3OH adsorption property on the top surface of the (10, 0 zigzag single-walled pristine Carbon nanotube (C-CNT, Boron doped carbon nanotube (B-CNT, and Silicon doped carbon nanotube (Si-CNT are investigated by using density functional theory (DFT computations to exploit their potential applications as gas sensors. For the first time, we calculated the optimal equilibrium position, absorption energy (Ead, and density of states (DOS of the considered gas molecules adsorbed on the open end of zigzag single-walled (10, 0 B-CNT and Si-CNT. Our first principle calculations demonstrate that the B-CNT and Si-CNT adsorbent materials are able to adsorb the considered gas molecules with variety of adsorption energy and their electronic structure dramatic changes in the density of states near the Fermi level. The obtained comparative DFT studies results are useful for designing a high-fidelity gas sensor materials and selective adsorbents for a selective gas sensor.

  14. LIQUIFIED NATURAL GAS (LNG CARRIERS

    Directory of Open Access Journals (Sweden)

    Daniel Posavec

    2010-12-01

    Full Text Available Modern liquefied natural gas carriers are double-bottom ships classified according to the type of LNG tank. The tanks are specially designed to store natural gas cooled to -161°C, the boiling point of methane. Since LNG is highly flammable, special care must be taken when designing and operating the ship. The development of LNG carriers has begun in the middle of the twentieth century. LNG carrier storage space has gradually grown to the current maximum of 260000 m3. There are more than 300 LNG carriers currently in operation (the paper is published in Croatian.

  15. Structural and magnetic ordering of CrNb3S6 single crystals grown by gas transport method

    Science.gov (United States)

    Borisenko, E. B.; Berezin, V. A.; Kolesnikov, N. N.; Gartman, V. K.; Matveev, D. V.; Shakhlevich, O. F.

    2017-07-01

    Paramagnetic layered semiconductor NbS2 doped with some transition metals can transform into ferromagnetic material. That is why such materials are promising candidates for spintronic devices. It is found that only at certain concentrations of a doping metal T crystallographic ordering is possible, which is essential for magnetic ordering of ternary compounds TNbS2. In particular, CrNb3S6 crystals are studied, which form almost completely ordered superstructure with intercalated Cr between NbS2 layers. The main difficulty in crystal growth is reaching stoichiometry of the compound. This problem is solved in the developed method of two-staged gas transport chemical reaction. This new approach provides growth of CrNb3S6 single crystals of several millimeters in diameter and 0.3-0.5 mm thickness. X-ray phase analysis (XRD) of powders is performed to identify all phases involved in synthesis and growth of the crystals. High frequency absorption in external periodic magnetic field as a function of temperature and intensity of magnetic field is used to estimate the temperature of ferromagnetic transition in CrNb3S6 single crystals. The Curie temperature is estimated as 115 K. Growth of CrNb3S6 crystals from vapor phase is studied in detail and full analysis of phase transitions during growth is given. It has been shown that using of high frequency absorption in the crystal provides reliable estimation of the point of ferromagnetic transition in this semiconductor. The authors are grateful to the Physical Science Department of Russian Academy of Sciences for financial support of the studies in the frameworks of the program "Physics of new materials and structures" (project no. 00-12-10).

  16. Calculation of the upper flammability limit of methane/air mixtures at elevated pressures and temperatures.

    Science.gov (United States)

    Van den Schoor, F; Verplaetsen, F; Berghmans, J

    2008-05-30

    Four different numerical methods to calculate the upper flammability limit of methane/air mixtures at initial pressures up to 10 bar and initial temperatures up to 200 degrees C are evaluated by comparison with experimental data. Planar freely propagating flames are calculated with the inclusion of a radiation heat loss term in the energy conservation equation to numerically obtain flammability limits. Three different reaction mechanisms are used in these calculations. At atmospheric pressure, the results of these calculations are satisfactory. At elevated pressures, however, large discrepancies are found. The spherically expanding flame calculations only show a marginal improvement compared with the planar flame calculations. On the other hand, the application of a limiting burning velocity with a pressure dependence Su,lim approximately p(-1/2) is found to predict the pressure dependence of the upper flammability limit very well, whereas the application of a constant limiting flame temperature is found to slightly underestimate the temperature dependence of the upper flammability limit.

  17. 14 CFR 26.39 - Newly produced airplanes: Fuel tank flammability.

    Science.gov (United States)

    2010-01-01

    ... TRANSPORTATION AIRCRAFT CONTINUED AIRWORTHINESS AND SAFETY IMPROVEMENTS FOR TRANSPORT CATEGORY AIRPLANES Fuel...) that meet the requirements of 14 CFR 25.981 in effect on December 26, 2008. (1) The fuel tank is... tank exceeds a Fleet Average Flammability Exposure of 7 percent. (c) All other fuel tanks that...

  18. 30 CFR 35.22 - Test to determine effect of evaporation on flammability.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Test to determine effect of evaporation on... § 35.22 Test to determine effect of evaporation on flammability. (a) Purpose. The purpose of this test shall be to determine the effect of evaporation on the reduction of fire resistance of a hydraulic...

  19. MESERAN Test Results for Elimination of Flammable Solvents in Wipe Applications at Pantex

    Energy Technology Data Exchange (ETDEWEB)

    M. G. Benkovich

    2005-03-30

    In recent years, efforts have been made within the nuclear weapons complex (National Nuclear Security Administration) of the Department of Energy (DOE) to replace Resource Conservation and Recovery Act (RCRA) regulated solvents (i.e., flammable, toxic, corrosive, and reactive) and ozone-depleting chemicals (ODC) with more benign alternatives. Within the National Nuclear Security Administration (NNSA) and the Department of Defense (DoD) sectors, these solvents are used for cleaning hardware during routine maintenance operations. A primary goal of this study is to replace flammable solvents for wiping applications. Two cleaners, including a hydrofluoroether (HFE) and an azeotrope of the HFE and isopropyl alcohol (IPA), have been studied as potential replacements for flammable solvents. Cleaning efficacy, short-term and longterm materials compatibility, corrosion, drying times, flammability, environment, safety and health (ES&H) issues and accelerated aging studies are among the tests that are being conducted and that are used to screen candidate solvents by the interagency team performing this work. The results are compared to the traditionally used isopropyl alcohol, which serves as the baseline cleaner. This report details the results of MESERAN (Measurement and Evaluation of Surfaces by Evaporative Rate ANalysis) testing performed at the Kansas City Plant (KCP) to quantify the cleaning efficacy on samples contaminated with the various contaminants and cleaned by wiping with the various solvents being evaluated.

  20. Group-Contribution based Property Estimation and Uncertainty analysis for Flammability-related Properties

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Marcarie, Camille; Abildskov, Jens

    2016-01-01

    This study presents new group contribution (GC) models for the prediction of Lower and Upper Flammability Limits (LFL and UFL), Flash Point (FP) and Auto Ignition Temperature (AIT) of organic chemicals applying the Marrero/Gani (MG) method. Advanced methods for parameter estimation using robust...

  1. Non-Toxic, Non-Flammable, -80 C Phase Change Materials

    Science.gov (United States)

    Cutbirth, J. Michael

    2013-01-01

    The objective of this effort was to develop a non-toxic, non-flammable, -80 C phase change material (PCM) to be used in NASA's ICEPAC capsules for biological sample preservation in flight to and from Earth orbit. A temperature of about -68 C or lower is a critical temperature for maintaining stable cell, tissue, and cell fragment storage.

  2. The detection of single electrons using a Microgas gas amplification and a MediPix2 CMOS pixel readout

    NARCIS (Netherlands)

    Forniani, A.; Campbell, M.; Chefdeville, M.A.; Colas, P.; Colijn, A.P.; Graaf, van der H.; Giomataris, Y.; Heijne, E.H.M.; Kluit, P.; Llopart, X.; Schmitz, J.; Timmermans, J.; Visschers, J.L.

    2005-01-01

    By placing a Micromegas gas gain grid on top of a CMOS pixel readout circuit (MediPix2), we developed a device which acts as a pixel-segmented direct anode in gas-filled detectors. With a He/Isobutane 80/20 mixture (capable of achieving gas gain factors up to 20×103) and employing a drift length of

  3. A THEORETICAL-MODEL FOR THE INFLUENCE OF GAS PROPERTIES AND PRESSURE ON SINGLE-BUBBLE FORMATION AT AN ORIFICE

    NARCIS (Netherlands)

    WILKINSON, PM; VANDIERENDONCK, LL

    1994-01-01

    A number of authors have on the basis of experiments determined that pressure and gas density can have an influence on bubble formation size. Usually this influence is attributed to the gas momentum force, generated by gas flowing into the bubble during its formation. In this article the theoretical

  4. Standard test method for isotopic analysis of uranium hexafluoride by double standard single-collector gas mass spectrometer method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This is a quantitative test method applicable to determining the mass percent of uranium isotopes in uranium hexafluoride (UF6) samples with 235U concentrations between 0.1 and 5.0 mass %. 1.2 This test method may be applicable for the entire range of 235U concentrations for which adequate standards are available. 1.3 This test method is for analysis by a gas magnetic sector mass spectrometer with a single collector using interpolation to determine the isotopic concentration of an unknown sample between two characterized UF6 standards. 1.4 This test method is to replace the existing test method currently published in Test Methods C761 and is used in the nuclear fuel cycle for UF6 isotopic analyses. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro...

  5. Gas-phase production of single-walled carbon nanotubes from carbon monoxide: a review of the hipco process

    Science.gov (United States)

    Nikolaev, Pavel

    2004-01-01

    The latest process for producing large quantities of single-walled carbon nanotubes (SWNTs) to emerge from the Rice University, dubbed HiPco, is living up to its promise. The current production rates approach 450 mg/h (or 10 g/day), and nanotubes typically have no more than 7 mol % of iron impurities. Second-generation HiPco apparatus can run continuously for 7-10 days at a time. In the HiPco process nanotubes grow in high-pressure, high-temperature flowing CO on catalytic clusters of iron. Catalyst is formed in situ by thermal decomposition of iron pentacarbonyl, which is delivered intact within a cold CO flow and then rapidly mixed with hot CO in the reaction zone. Upon heating, the Fe(CO)5 decomposes into atoms that condense into larger clusters. SWNTs nucleate and grow on these particles in the gas phase via CO disproportionation: CO + CO --> CO2 + C (SWNT), catalyzed by the Fe surface. The concentration of CO2 produced in this reaction is equal to that of carbon and can therefore serve as a useful real-time feedback parameter. It was used to study and optimize SWNT production as a function of temperature, pressure, and Fe(CO)5 concentration. The results of the parametric study are in agreement with current understanding of the nanotube formation mechanism.

  6. Effect of phonon focusing on Knudsen flow of phonon gas in single-crystal nanowires made of spintronics materials

    Science.gov (United States)

    Kuleev, I. I.; Bakharev, S. M.; Kuleev, I. G.; Ustinov, V. V.

    2017-01-01

    Effect of anisotropy of elastic energy on the phonon propagation in single-crystal nanowires made of Fe, Cu, MgO, InSb, and GaAs materials that are used to fabricate spintronics devices in the regime of the Knudsen flow of phonon gas has been studied. A new method of analyzing the focusing of quasi-transverse modes has been suggested, which made it possible to determine the average values of the densities of phonon states in the regions of focusing and defocusing slow and fast quasi-transverse modes. The effect of phonon focusing on the anisotropy of heat conductivity and lengths of the phonon free paths has been analyzed for all acoustic modes that exist in spintronics nanostructures. It has been shown that for all the nanowires investigated the angular dependences of the free paths of fast and slow transverse modes in the {100} and {110} planes correlate with the angular dependences of the densities of phonon states for these modes. Directions of the heat flux that ensure the maximum and minimum phonon heat conductivity in the nanowires have been determined.

  7. Flammability of Some Ornamental Species in Wildland-Urban Interfaces in Southeastern France: Laboratory Assessment at Particle Level

    Science.gov (United States)

    Ganteaume, Anne; Jappiot, Marielle; Lampin, Corinne; Guijarro, Mercedes; Hernando, Carmen

    2013-08-01

    Assessment of the flammability of ornamental vegetation (particularly hedges) planted around houses is necessary in light of the increasing urbanization of the wildland-urban interfaces (WUIs) and the high fire occurrence in such areas. The structure and flammability of seven of the species most frequently planted as hedges in Provence (southeastern France) were studied at particle level. Spatial repartition of the different types of fuel particles within plants was assessed by means of the cube method. The leaf flammability was assessed using an epiradiator as a burning device, and measurements of foliar physical characteristics and gross heat of combustion (GHC) helped to explain the results of burning experiments. Co-inertia analysis revealed that species with thin leaves were quick to ignite ( Pyracantha coccinea, Phyllostachys sp.) and species with high leaf GHC burned the longest ( Pittosporum tobira, Nerium oleander). Species presenting high ignitability ( Photinia fraseri, Phyllostachys sp. and Pyracantha coccinea) were characterized by high foliar surface area-to-volume ratio, and species presenting lower ignitability were characterized by high GHC ( Pittosporum tobira, Nerium oleander, Cupressus sempervirens). Hierarchical cluster analysis of the flammability variables (ignition frequency, time-to-ignition and flaming duration) categorized the relative flammability of the seven species (including dead Cupressus sempervirens) in five clusters of species from poorly flammable ( Pittosporum tobira) to extremely flammable (dead Cupressus sempervirens).This study provides useful information for reducing fire risk in WUIs in the study area.

  8. Drag reduction by polymer addition in single and two-phase gas-liquid flows in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Bizotto, Vanessa Cristina; Paes, Diogo Melo; Franca, Fernando de Almeida [Universidade Estadual de Campinas, SP (Brazil). Centro de Estudos de Petroleo. LabPetro]. E-mails: vanessa@cepetro.unicamp.br; diogopaes10@hotmail.com; Sabadini, Edvaldo [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica]. E-mails: sabadini@iqm.unicamp.br; ffranca@fem.unicamp.br

    2008-07-01

    Turbulence mechanisms, as the eddies formation frequency and size, promote energy dissipation that appears as pressure drop in pipe flows. Adding minute amounts of polymers - ppm - of high molecular weight to the solution can lead to the reduction of the viscous dissipation. The formed macromolecules interact with the eddies, cause the eddies coherence breakdown, damp the energy transport and reduces the pressure drop. This phenomenon is known as the hydrodynamic drag reduction (DR, for short). Thus, for a given pipe flow rate there is decrease in pressure head, which is a desired operating strategy when transporting liquids. Studies on the hydrodynamic drag reduction in polymeric systems have been carried out in collaboration by the Chemistry Institute and the Petroleum Laboratory - LabPetro, UNICAMP. These studies have allowed microscopic approaches to the engineering scales, tackling the most usual processes - single phase flows, as well as gas-liquid two-phase flows in pipelines, which are quite common in the chemical and the petroleum industries. Tests conducted in the Chemistry Institute comprised over-the-bench experimentations made with a rotational double-gap type rheometer. These quick performed tests used small amount of polymers, and provided information on the additive concentration, the drag reduction and the solution mechanical stability along a turbulent shearing process. The results indicated that 17% is the limiting drag reduction achieved when a 2 ppm aqueous solution of polyacrylamide - PAM - was tested. These tests, besides giving preliminary estimations, are limited in terms of engineering application due to the low shearing rates applied by the viscometer. The tests performed at LabPetro comprised pressure drop measurements in actual pipe flows, both water single and air-water two-phase flows, using the previous knowledge acquired with the viscometer tests. In the former case, the Prandtl-von Karman map has been drawn to show the %DR in terms

  9. Dispersion coefficients for the interaction of inert gas atoms with alkali and alkaline earth ions and alkali atoms with their singly ionized ions

    CERN Document Server

    Singh, Sukhjit; Sahoo, B K; Arora, Bindiya

    2016-01-01

    We report the dispersion coefficients for the interacting inert gas atoms with the alkali ions, alkaline earth ions and alkali atoms with their singly charged ions. We use our relativistic coupled-cluster method to determine dynamic dipole and quadrupole polarizabilities of the alkali atoms and singly ionized alkaline earth atoms, whereas a relativistic random phase approximation approach has been adopted to evaluate these quantities for the closed-shell configured inert gas atoms and the singly and doubly ionized alkali and alkaline earth atoms, respectively. Accuracies of these results are adjudged from the comparison of their static polarizability values with their respective experimental results. These polarizabilities are further compared with the other theoretical results. Reason for the improvement in the accuracies of our estimated dispersion coefficients than the data listed in [At. Data and Nucl. Data Tables 101, 58 (2015)] are discussed. Results for some of the atom-ion interacting systems were not...

  10. Estimation and Uncertainty Analysis of Flammability Properties for Computer-aided molecular design of working fluids for thermodynamic cycles

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Abildskov, Jens; Sin, Gürkan

    assessment of novel working fluids relies on accurate property data. Flammability data like the lower and upper flammability limit (LFL and UFL) play an important role in quantifying the risk of fire and explosion. For novel working fluid candidates experimental values are not available for the safety...... analysis. In this case property prediction models like group contribution (GC) models can estimate flammability data. The estimation needs to be accurate, reliable and as less time consuming as possible [1]. However, GC property prediction methods frequently lack rigorous uncertainty analysis. Hence...

  11. Single-Step, Solvent-Free, Catalyst-Free Preparation of Holey Carbon Allotropes

    Science.gov (United States)

    Lin, Yi (Inventor); Kim, Jae-Woo (Inventor); Connell, John W. (Inventor); Funk, Michael R. (Inventor); Campbell, Caroline J. (Inventor)

    2017-01-01

    Methods for forming holey carbon allotropes and graphene nanomeshes are provided by the various embodiments. The various embodiments may be applicable to a variety of carbon allotropes, such as graphene, graphene oxide, reduced graphene oxide, thermal exfoliated graphene, graphene nanoribbons, graphite, exfoliated graphite, expanded graphite, carbon nanotubes (e.g., single-walled carbon nanotubes, double-walled carbon nanotubes, few-walled carbon nanotubes, multi-walled carbon nanotubes, etc.), carbon nanofibers, carbon fibers, carbon black, amorphous carbon, fullerenes, etc. The methods may produce holey carbon allotropes without the use of solvents, catalysts, flammable gas, additional chemical agents, or electrolysis to produce the pores (e.g., holes, etc.) in the carbon allotropes. In an embodiment, a carbon allotrope may be heated at a working window temperature for a working period of time to create holes in the carbon allotrope.

  12. Mathematical modelling of porous silicon based pellistor-type catalytic flammable gas sensors

    NARCIS (Netherlands)

    Kolev, S.D.; Kolev, S.D.; Adam, M.; Barsony, I.; Barsony, I.; van den Berg, Albert; Cobianu, C.

    1998-01-01

    The development of a three-dimensional thermal mathematical model of a pellistor based on the fundamental physical laws of heat transfer and employing a few clearly stated simplifying assumptions concerning the convective heat transfer in ambient air is reported. The model was numerically solved

  13. Flammable gas deflagration consequence calculations for the tankwaste remediation system basis for interim operation

    Energy Technology Data Exchange (ETDEWEB)

    Van Vleet, R.J., Westinghouse Hanford

    1996-09-23

    This paper calculates the radiological dose consequences and the toxic exposures for deflagration accidents at various Tank Waste Remediation System facilities. These will be used in support of the Tank Waste Remediation System Basis for Interim Operation.

  14. 下水道和化粪池内可燃气体浓度预警模式研究%Study on Early Warning Mode of Flammable Gases Concentration in Urban Sewers and Septic Tanks

    Institute of Scientific and Technical Information of China (English)

    米莉; 彭乾皓; 彭绪亚

    2012-01-01

    The establishment of gas safety monitoring system of sewers and septic tanks to achieve off-gauge early warning of flammable gases concentration is an effective way to prevent and reduce gas explosion accidents. This study addresses frequent alarm and false alarm phenomena in gas monitoring system by field investigation and data collection of gas explosions in metropolitan Chongqing. Also, data from Nan' an District was collected for one year and the early warning modes of flammable gases concentration were established; stability mode, perturbation mode and accumulation mode. Discrimination standards were determined. The discrimination standard was based on concentration trends of flammable gases. If the concentration at a subsequent moment is consistently three times higher than that at its preceding moment during a sampling period, an increasing trend of flammable gases concentration is marked. According to this discrimination standard, the alarm frequency of the existing gas safety monitoring system can be reduced by at least half, improving the system reliability and validity.%建立下水道和化粪池气体安全监控系统,实现可燃气体浓度超限预警是预防和减少下水道和化粪池气体爆炸事故的有效方式.针对现有气体安全监控系统存在的频繁报警与“误报”现象,通过现场调研和数据收集,分析重庆市主城区已发生气体爆炸事故以及重庆市南岸区一年来的监测数据,建立了可燃气体浓度预警模式:稳定模式、扰动模式和聚集模式,并建立了相应的判别标准.预警模式判别标准基于可燃气体浓度变化趋势判别式,若从某一采样时刻起,连续3次出现后一时刻的采样浓度大于前一时刻的现象,即判定为可燃气体浓度有增加趋势.通过该判别标准,至少能使现有系统报警次数减少50%,从而提高气体监控预警系统的可靠性和有效性.

  15. Hydrogen gas production is associated with reduced interleukin-1β mRNA in peripheral blood after a single dose of acarbose in Japanese type 2 diabetic patients.

    Science.gov (United States)

    Tamasawa, Atsuko; Mochizuki, Kazuki; Hariya, Natsuyo; Saito, Miyoko; Ishida, Hidenori; Doguchi, Satako; Yanagiya, Syoko; Osonoi, Takeshi

    2015-09-05

    Acarbose, an α-glucosidase inhibitor, leads to the production of hydrogen gas, which reduces oxidative stress. In this study, we examined the effects of a single dose of acarbose immediately before a test meal on postprandial hydrogen gas in breath and peripheral blood interleukin (IL)-1β mRNA expression in Japanese type 2 diabetic patients. Sixteen Japanese patients (14 men, 2 women) participated in this study. The mean±standard deviation age, hemoglobin A1c and body mass index were 52.1±15.4 years, 10.2±2.0%, and 27.7±8.0kg/m(2), respectively. The patients were admitted into our hospital for 2 days and underwent test meals at breakfast without (day 1) or with acarbose (day 2). We performed continuous glucose monitoring and measured hydrogen gas levels in breath, and peripheral blood IL-1β mRNA levels before (0min) and after the test meal (hydrogen gas: 60, 120, 180, and 300min; IL-1β: 180min). The induction of hydrogen gas production and the reduction in peripheral blood IL-1β mRNA after the test meal were not significant between days 1 (without acarbose) and 2 (with acarbose). However, the changes in total hydrogen gas production from day 1 to day 2 were closely and inversely associated with the changes in peripheral blood IL-1β mRNA levels. Our results suggest that an increase in hydrogen gas production is inversely associated with a reduction of the peripheral blood IL-1β mRNA level after a single dose of acarbose in Japanese type 2 diabetic patients. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Gas phase synthesis of non-bundled, small diameter single-walled carbon nanotubes with near-armchair chiralities

    Energy Technology Data Exchange (ETDEWEB)

    Mustonen, K.; Laiho, P.; Kaskela, A.; Zhu, Z.; Reynaud, O.; Houbenov, N.; Tian, Y.; Jiang, H.; Kauppinen, E. I., E-mail: esko.kauppinen@aalto.fi [Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto (Finland); Susi, T. [Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna (Austria); Nasibulin, A. G. [Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto (Finland); Skolkovo Institute of Science and Technology, Nobel str. 3, 143026 (Russian Federation); Saint-Petersburg State Polytechnical University, 29 Polytechniheskaya st., St. Petersburg, 195251 (Russian Federation)

    2015-07-06

    We present a floating catalyst synthesis route for individual, i.e., non-bundled, small diameter single-walled carbon nanotubes (SWCNTs) with a narrow chiral angle distribution peaking at high chiralities near the armchair species. An ex situ spark discharge generator was used to form iron particles with geometric number mean diameters of 3–4 nm and fed into a laminar flow chemical vapour deposition reactor for the continuous synthesis of long and high-quality SWCNTs from ambient pressure carbon monoxide. The intensity ratio of G/D peaks in Raman spectra up to 48 and mean tube lengths up to 4 μm were observed. The chiral distributions, as directly determined by electron diffraction in the transmission electron microscope, clustered around the (n,m) indices (7,6), (8,6), (8,7), and (9,6), with up to 70% of tubes having chiral angles over 20°. The mean diameter of SWCNTs was reduced from 1.10 to 1.04 nm by decreasing the growth temperature from 880 to 750 °C, which simultaneously increased the fraction of semiconducting tubes from 67% to 80%. Limiting the nanotube gas phase number concentration to ∼10{sup 5 }cm{sup −3} prevented nanotube bundle formation that is due to collisions induced by Brownian diffusion. Up to 80% of 500 as-deposited tubes observed by atomic force and transmission electron microscopy were individual. Transparent conducting films deposited from these SWCNTs exhibited record low sheet resistances of 63 Ω/□ at 90% transparency for 550 nm light.

  17. Preparation and characterization of poly(methyl methacrylate)-clay nanocomposites via melt intercalation: Effect of organoclay on thermal, mechanical and flammability properties

    Energy Technology Data Exchange (ETDEWEB)

    Unnikrishnan, Lakshmi; Mohanty, Smita [Laboratory for Advanced Research in Polymeric Materials (LARPM), Central Institute of Plastics Engineering and Technology, Bhubaneswar 751024 (India); Nayak, Sanjay K., E-mail: drsknayak@gmail.com [Laboratory for Advanced Research in Polymeric Materials (LARPM), Central Institute of Plastics Engineering and Technology, Bhubaneswar 751024 (India); Ali, Anwar [Laboratory for Advanced Research in Polymeric Materials (LARPM), Central Institute of Plastics Engineering and Technology, Bhubaneswar 751024 (India)

    2011-05-15

    Research highlights: {yields} The present work deals with preparation and characterization of poly(methyl methacrylate) nanocomposites via melt intercalation technique. {yields} The effect of various modified nanoclays on the properties of base matrix has been investigated. {yields} It was observed that compatibilization using maleic anhydride improved the performance characteristics of PMMA/layered silicate nanocomposites. - Abstract: The PMMA nanocomposites were prepared by melt processing method. The influence of organoclay loading on extent of intercalation, thermal, mechanical and flammability properties of poly(methyl methacrylate) (PMMA)-clay nanocomposites were studied. Three different organoclay modifiers with varying hydrophobicity (single tallow vs. ditallow) were investigated. The nanocomposites were characterized by using wide angle X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, differential scanning calorimetry (DSC), and tensile tests. The intercalation of polymer chain within the silicate galleries was confirmed by WAXD and TEM. Mechanical properties such as tensile modulus (E), tensile strength, percentage elongation at break and impact strength were determined for nanocomposites at various clay loadings. Overall thermal stability of nanocomposites increased by 16-17 deg. C. The enhancement in T{sub g} of nanocomposite is merely by 2-4 deg. C. The incorporation of maleic anhydride as compatibilizer further enhanced all the properties indicating improved interface between PMMA and clay. The flammability characteristics were studied by determining the rate of burning and LOI.

  18. Analysis of Single Point Well Test in Changling Gas Field%长岭气田一点法产能试井分析

    Institute of Scientific and Technical Information of China (English)

    贺英; 贾永禄; 阮宝涛; 杨思松

    2012-01-01

    Changling gas field is a typical volcanic gas reservoir with low porosity and low permeability.In well testing,in order to reduce the amount of natural gas emission,single point method is normally used to calculate absolute open flow of gas wells.However,the values——of parameter α in different gas fields are quite different.This paper studied six wells' testing data,found out that some well productivity curves were reverse,for which the abnormal well testing data were processed,correcting this part of well productivity data.And through getting each well productivity factor by using binomial equation and the average factor(α=0.494 3) of Changling gas field,the single point empirical formula for this gas field is obtained.Moreover,this paper presents the comparisons of this formula with the absolute open flows from stable well testing and single point methods proposed by ChenYuanqian and Changqing gas field.And the results indicate that this formula is suitable and practical for Changling gas field.%现场多采用一点法计算气井无阻流量而减少放空量。但是在应用一点法产能试井公式计算气井无阻流量时,不同气田的经验参数α值差异较大。研究了长岭气田6口稳定试井资料,发现部分井产能曲线反向,通过处理,校正了这部分井的产能数据。通过计算每口井的二项式产能方程,获取了每口井的产能系数,计算出长岭气田平均的产能系数(α=0.494 3),得到了长岭气田的一点法经验公式。通过与稳定测试得到的无阻流量进行比较,以及与常用的陈元千一点法、长庆气田一点法等计算结果进行对比,表明本文得到的一点法公式符合长岭气田实际情况。

  19. Estimation and Uncertainty Analysis of Flammability Properties for Computer-aided molecular design of working fluids for thermodynamic cycles

    OpenAIRE

    Frutiger, Jerome; Abildskov, Jens; Sin, Gürkan

    2015-01-01

    Computer Aided Molecular Design (CAMD) is an important tool to generate, test and evaluate promising chemical products. CAMD can be used in thermodynamic cycle for the design of pure component or mixture working fluids in order to improve the heat transfer capacity of the system. The safety assessment of novel working fluids relies on accurate property data. Flammability data like the lower and upper flammability limit (LFL and UFL) play an important role in quantifying the risk of fire and e...

  20. THE IMPACT OF OZONE ON THE LOWER FLAMMABLE LIMIT OF HYDROGEN IN VESSELS CONTAINING SAVANNAH RIVER SITE HIGH LEVEL WASTE

    Energy Technology Data Exchange (ETDEWEB)

    Sherburne, Carol [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Remediation, LLC; Osterberg, Paul [Fauske and Associates, LLC, Burr Ridge, IL (United States); Johnson, Tom [Fauske and Associates, LLC, Burr Ridge, IL (United States); Frawely, Thomas [Fauske and Associates, LLC, Burr Ridge, IL (United States)

    2013-01-23

    The Savannah River Site, in conjunction with AREVA Federal services, has designed a process to treat dissolved radioactive waste solids with ozone. It is known that in this radioactive waste process, radionuclides radiolytically break down water into gaseous hydrogen and oxygen, which presents a well defined flammability hazard. Flammability limits have been established for both ozone and hydrogen separately; however, there is little information on mixtures of hydrogen and ozone. Therefore, testing was designed to provide critical flammability information necessary to support safety related considerations for the development of ozone treatment and potential scale-up to the commercial level. Since information was lacking on flammability issues at low levels of hydrogen and ozone, a testing program was developed to focus on filling this portion of the information gap. A 2-L vessel was used to conduct flammability tests at atmospheric pressure and temperature using a fuse wire ignition source at 1 percent ozone intervals spanning from no ozone to the Lower Flammable Limit (LFL) of ozone in the vessel, determined as 8.4%(v/v) ozone. An ozone generator and ozone detector were used to generate and measure the ozone concentration within the vessel in situ, since ozone decomposes rapidly on standing. The lower flammability limit of hydrogen in an ozone-oxygen mixture was found to decrease from the LFL of hydrogen in air, determined as 4.2 % (v/v) in this vessel. From the results of this testing, Savannah River was able to develop safety procedures and operating parameters to effectively minimize the formation of a flammable atmosphere.

  1. A Review of the Flammability Factors of Kenaf and Allied Fibre Reinforced Polymer Composites

    Directory of Open Access Journals (Sweden)

    C. H. Lee

    2014-01-01

    Full Text Available Natural fibre is a well-known reinforcement fibre in polymer-matrix Composites (PMC lately. Natural fibre has fast growing and abundance properties which make it available at very low cost. For kenaf fibre there is long lists of research projects which have been done regarding its behaviour, and properties and modification made to it. In this paper, fire flammability is the main concern for natural fibre reinforced polymer (NFRP composites especially kenaf fibre. To estimate its flammability, a wide range of factors can be considered such as fibre content, type of matrices, pH conditions, treatment, and fire retardant (FR filler’s type. The most important criteria are the ignition time, rate of propagation, and fire behavior. thermogravimetric analysis (TGA, different scanning calorimetric (DSC, and dynamic mechanical analysis (DMA are the three most famous methods used to investigate the fire behaviour of composites.

  2. Estimation and Uncertainty Analysis of Flammability Properties of Chemicals using Group-Contribution Property Models

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Abildskov, Jens; Sin, Gürkan

    or time constraints, property prediction models like group contribution (GC) models can estimate flammability data. The estimation needs to be accurate, reliable and as less time consuming as possible. However, GC property prediction methods frequently lack rigorous uncertainty analysis. Hence......, there is no information about the reliability of the data. Furthermore, the global optimality of the GC parameters estimation is often not ensured. In this research project flammability-related property data, like LFL and UFL, are estimated using the Marrero and Gani group contribution method (MG method). In addition...... the group contribution in three levels: The contributions from a specific functional group (1st order parameters), from polyfunctional (2nd order parameters) as well as from structural groups (3rd order parameters). The latter two classes of GC factors provide additional structural information beside...

  3. Plasmonic nanoantenna array with single-chip integrated metal-organic framework for infrared absorption gas sensing (Conference Presentation)

    Science.gov (United States)

    Chong, Xinyuan; Kim, Ki-Joong; Li, Erwen; Zhang, Yujing; Ohodnicki, Paul R.; Chang, Chih-Hung; Wang, Alan X.

    2017-03-01

    Surface-enhanced infrared absorption (SEIRA) is a spectroscopic technique used to identify molecular fingerprints by resonant detection of infrared vibrational modes through coupling with the plasmonic modes of metallic nanostructures. Many reported works have demonstrated its capability to enhance the infrared absorption of solid or liquid samples. However, this technique has not been successfully applied to gas sensing yet due to the short light-matter interaction length and intrinsically weak absorption of gas compared to solid or liquid materials. Usually, IR gas sensing is conducted in a gas cell with a long absorption path. In the paper, we propose an integrated photonic device to expand the application of SEIRA to gas sensing by combining metal-organic framework (MOF) ZIF-8 (zeolitic imidazole framework) with plasmonic nanoantenna array. The device consists of an Au nanopatch array on sapphire substrate and is covered by a thin layer of MOF material. The MOF thin film, which is a new class of highly nanoporous material, serves as a gas absorber to selectively adsorb and concentrate CO2 from ambient environment into the thin layer, which has a high spatial overlap with the high intensity optical field of the plasmonic nanopatch antenna array. Namely, we can effectively increase the gas molecule concentration at the hot-spots for the SEIRA device. The experimentally demonstrated peak IR enhancement factor of the device for carbon dioxide sensing is over 1,100 times.

  4. Hydrogen mitigation Gas Characterization System: System design description

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, T.C.

    1998-07-17

    The Gas Characterization System (GCS) design is described for flammable gas monitoring. Tank 241-SY-101 (SY-101) is known to experience periodic tank level increases and decreases during which hydrogen gas is released. It is believed that the generated gases accumulate in the solids-containing layer near the bottom of the tank. Solids and gases are also present in the crust and may be present in the interstitial liquid layer. The accumulation of gases creates a buoyancy that eventually overcomes the density and bonding strength of the bottom layer. When this happens, the gas from the bottom layer is released upward through the liquid layer to the vapor space above the tank crust. Previous monitoring of the vapor space gases during such an event indicates hydrogen release concentrations greater than the lower flammability limit (LFL) of hydrogen in a partial nitrous oxide atmosphere. Tanks 241-AN-105, 241-AW-101, and 241-SY-103 have been identified as having the potential to behave similar to SY-101. These waste tanks have been placed on the flammable gas watch list (FGWL). All waste tanks on the FGWL will have a standard hydrogen monitoring system (SHMS) installed to measure hydrogen. In the event that hydrogen levels exceed 0.75% by volume, additional characterization will be required. The purpose of this additional vapor space characterization is to determine the actual lower flammability limit of these tanks, accurately measure low baseline gas release concentrations, and to determine potential hazards associated with larger Gas Release Events (GREs). The instruments to be installed in the GCS for vapor monitoring will allow accurate analysis of samples from the tank vapor space. It will be possible to detect a wide range of hydrogen from parts per million to percent by volume, as well as other gas species suspected to be generated in waste tanks.

  5. Computer systems and software description for gas characterization system

    Energy Technology Data Exchange (ETDEWEB)

    Vo, C.V.

    1997-04-01

    The Gas Characterization System Project was commissioned by TWRS management with funding from TWRS Safety, on December 1, 1994. The project objective is to establish an instrumentation system to measure flammable gas concentrations in the vapor space of selected watch list tanks, starting with tank AN-105 and AW-101. Data collected by this system is meant to support first tank characterization, then tank safety. System design is premised upon Characterization rather than mitigation, therefore redundancy is not required.

  6. The hydrogen–air burning rate near the lean flammability limit

    OpenAIRE

    Fernández Galisteo, Daniel; Sánchez Pérez, Antonio Luis; Liñán Martínez, Amable; Williams, F. A.

    2009-01-01

    This paper investigates the inner structure of the thin reactive layer of hydrogen–air fuellean deflagrations close to the flammability limit. The analysis, which employs seven elementary reactions for the chemistry description, uses the ratio of the characteristic radical and fuel concentrations as a small asymptotic parameter, enabling an accurate analytic expression for the resulting burning rate to be derived. The analysis reveals that the steady-state assumption for chemical intermedi...

  7. Prediction of upper flammability limit percent of pure compounds from their molecular structures.

    Science.gov (United States)

    Gharagheizi, Farhad

    2009-08-15

    In this study, a quantitative structure-property relationship (QSPR) is presented to predict the upper flammability limit percent (UFLP) of pure compounds. The obtained model is a five parameters multi-linear equation. The parameters of the model are calculated only from chemical structure. The average absolute error and squared correlation coefficient of the obtained model over all 865 pure compounds used to develop the model are 9.7%, and 0.92, respectively.

  8. Cleaning and materials compatibility test results for elimination of flammable solvents in wipe applications.

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Edwin Paul

    2005-06-01

    In recent years, efforts have been made within the nuclear weapons complex (National Nuclear Security Administration) of the Department of Energy (DOE) to replace Resource Conservation and Recovery Act (RCRA) regulated solvents (i.e., flammable, toxic, corrosive, and reactive) and ozone-depleting chemicals (ODC) with more benign alternatives. Within the National Nuclear Security Administration (NNSA) and the Department of Defense (DoD) sectors, these solvents are used for cleaning hardware during routine maintenance operations. A primary goal of this study is to replace flammable solvents used in wiping applications. Two cleaners, including a hydrofluoroether (HFE) and an azeotrope of the HFE and isopropyl alcohol (IPA), have been studied as potential replacements for flammable solvents. Cleaning efficacy, short-term and long-term materials compatibility, corrosion, drying times, flammability, environment, safety and health (ES&H) and accelerated aging issues were among the experiments used to screen candidate solvents by the interagency team performing this work. This report presents cleaning efficacy results as determined by the contact angle Goniometer as well as materials compatibility results of various metal alloys and polymers. The results indicate that IPA (baseline cleaner) and the HFE/IPA azeotrope are roughly equivalent in their ability to remove fluorinated grease, silicone grease, and a simulated finger print contaminant from various metal alloys. All of the ASTM sandwich and immersion corrosion tests with IPA, HFE or the HFE/IPA azeotrope on metal alloys showed no signs of corrosion. Furthermore, no deleterious effects were noted for polymeric materials immersed in IPA, HFE, or the HFE/IPA azeotrope.

  9. Qualitative Assessment of the Ignition of Highly Flammable Fuels by Primary Explosives,

    Science.gov (United States)

    1983-06-01

    primary explosives used in the investigation are listed below:- basic lead azide lead azide lead styphnate barium styphnate potassium picrate lead...in Bakelite Tubes Basic Lead Azide w Lead Styphnate LDNR Barium Styphnate I Flash Composition Potassium Picrate I TABLE 3 IGNITION OF HEXANE SOAKED...Flammability Nichrome Bridgewire in Aluminium Tube Potassium Picrate X LDVR X Barium Styphnate X Tetracene X 200 mq Lead Styphnate X 400 mq Lead

  10. Textiles: Some technocal information and data III: Low flammable and other high performance fibres

    CSIR Research Space (South Africa)

    Hunter, L

    1978-07-01

    Full Text Available importance in the flammability performance is well illustrated in the case of certain wool shag carpets. Legislation for carpets sold in Canada requires that all carpets be tested under bone dry conditions. Consequently the natural moisture content... of the wool fibres (10-14%) is not available to prevent the spread of flame. If, however, these carpets were tested under higher relative humidity conditions the burning methenamine tablet employed as ignition source would not be sufficient to cause flame...

  11. Non-flammable electrolytes based on trimethyl phosphate solvent for lithium-ion batteries

    Institute of Scientific and Technical Information of China (English)

    HU Chuan-yue; LI Xin-hai

    2005-01-01

    The properties of trimethyl phosphate(TMP)-based nonflammable electrolytes with LiPF6 as solute were investigated using graphite anode and LiCoO2 cathode. The effect of TMP on non-flammability of electrolytes was also evaluated. It is found that the TMP reduction decomposition on graphite electrode at the potential of 1.3V (vs Li/Li+) is suppressed with ethylene carbonate(EC), dimethyl carbonate(DMC) and ethylmethyl carbonate(EMC) cosolvents and vinylene carbonate(VC) additives. The results show that the non-flammable electrolyte of 1mol/L LiPF6 61%(EC1.5-DMC1.0-EMC1.0)-39% TMP has good electrochemical properties. The discharge capacities of half-cells after 20 cycles are 254.8mA·h/g for Li/graphite and 144.1mA·h/g for Li/LiCoO2. The graphite/LiCoO2 prismatic lithium-ion cell delivers a discharge capacity of 131mA·h/g at first cycle. With an addition of 4%VC to this non-flammable electrolyte, a discharge capacity of 134mA·h/g at first cycle and a capacity ratio of 84.3% after 50 cycles are obtained for prismatic lithium-ion batteries. Furthermore, a nail penetration test demonstrates that the safety of prismatic lithium-ion batteries is dramatically improved by using TMP-containing non-flammable electrolytes.

  12. Inhibited flammability and surface inactivation of wood irradiated by low energy hydrogen ion showers (LEHIS)

    Energy Technology Data Exchange (ETDEWEB)

    Blantocas, Gene Q. [Plasma Physics Laboratory, National Institute of Physics, College of Science, University of the Philippines, Diliman, Quezon City 1101 (Philippines) and Physical Science Department, West Visayas State University, La Paz, Iloilo City 5000 (Philippines)]. E-mail: gqblantocas@yahoo.com; Mateum, Philip Edward R. [College of Architecture, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Orille, Ross William M. [College of Architecture, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Ramos, Rafael Julius U. [College of Architecture, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Monasterial, Jonathan Lee C. [Plasma Physics Laboratory, National Institute of Physics, College of Science, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Ramos, Henry J. [Plasma Physics Laboratory, National Institute of Physics, College of Science, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Bo-ot, Luis Ma.T. [Plasma Physics Laboratory, National Institute of Physics, College of Science, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Archilife Environ-Control Research Center, Department of Architecture, National Cheng Kung University, Tainan 701, Taiwan (China)

    2007-06-15

    Changes on the properties of wood irradiated by low energy hydrogen ion showers (LEHIS) were examined. The experimental facility employed was an in-house constructed, compact gas discharge ion source with beam energies maintained approximately in the 1keV range fixed at 1mA discharge current, 3mTorr gas filling pressure. Wood specimens used were of species endemic in the Philippines namely Shorea sp., Shorea polysperma and Cocos nucifera. Results showed the processed samples manifested characteristics of inhibited flammability, and became relatively hydrophobic after the treatment. In the fire resistance test, it was also observed during initial flaming that the processed surfaces accumulated less soot attesting to a much lower smoldering rate, i.e. lesser combustibility. To assess the increase in fire endurance time for the processed wood against the control substrates, a non-directional, two-tailed t-test was utilized. Significant at the 0.05 level, the t-statistic measured 9.164 as opposed to only 4.303 in its corresponding critical value at two degrees of freedom. Hence, the treatment appeared to show strong statistical evidence of being effective in enhancing fire resistance. The processed specimens also exhibited moisture absorptive inhibition time of more than 10min versus an average absorption period of just 8s for the unprocessed samples. Spectroscopy using a cast steel mass analyzer indicated a predominance of H{sup +} with faint signals of H{sub 2}{sup +} in the ion showers. It is hypothesized that the monatomic ion plays an essential participatory role in the surface modification process. Data from an earlier work using Narra wood (Pterocarpus indicus) [G.Q. Blantocas, H.J. Ramos, M. Wada, Jpn. J. Appl. Phys. 45 (2006) 8498] was extended in the current study to substantiate this hypothesis. The data is now presented as current density ratio H{sup +}/H{sub 2}{sup +} versus the change rate constant K of the wetting model equation. It is shown that wood

  13. Inhibited flammability and surface inactivation of wood irradiated by low energy hydrogen ion showers (LEHIS)

    Science.gov (United States)

    Blantocas, Gene Q.; Mateum, Philip Edward R.; Orille, Ross William M.; Ramos, Rafael Julius U.; Monasterial, Jonathan Lee C.; Ramos, Henry J.; Bo-ot, Luis Ma. T.

    2007-06-01

    Changes on the properties of wood irradiated by low energy hydrogen ion showers (LEHIS) were examined. The experimental facility employed was an in-house constructed, compact gas discharge ion source with beam energies maintained approximately in the 1 keV range fixed at 1 mA discharge current, 3 mTorr gas filling pressure. Wood specimens used were of species endemic in the Philippines namely Shorea sp., Shorea polysperma and Cocos nucifera. Results showed the processed samples manifested characteristics of inhibited flammability, and became relatively hydrophobic after the treatment. In the fire resistance test, it was also observed during initial flaming that the processed surfaces accumulated less soot attesting to a much lower smoldering rate, i.e. lesser combustibility. To assess the increase in fire endurance time for the processed wood against the control substrates, a non-directional, two-tailed t-test was utilized. Significant at the 0.05 level, the t-statistic measured 9.164 as opposed to only 4.303 in its corresponding critical value at two degrees of freedom. Hence, the treatment appeared to show strong statistical evidence of being effective in enhancing fire resistance. The processed specimens also exhibited moisture absorptive inhibition time of more than 10 min versus an average absorption period of just 8 s for the unprocessed samples. Spectroscopy using a cast steel mass analyzer indicated a predominance of H+ with faint signals of H2+in the ion showers. It is hypothesized that the monatomic ion plays an essential participatory role in the surface modification process. Data from an earlier work using Narra wood (Pterocarpus indicus) [G.Q. Blantocas, H.J. Ramos, M. Wada, Jpn. J. Appl. Phys. 45 (2006) 8498] was extended in the current study to substantiate this hypothesis. The data is now presented as current density ratio H+ /H2+versus the change rate constant K of the wetting model equation. It is shown that wood affinity to water decreased as the

  14. Flammability of self-extinguishing kenaf/ABS nanoclays composite for aircraft secondary structure

    Science.gov (United States)

    Karunakaran, S.; Majid, D. L.; Mohd Tawil, M. L.

    2016-10-01

    This study investigates the flammability properties of kenaf fiber reinforced acrylonitrile butadiene styrene (ABS) with nanoclays composites. Natural fiber is one of the potential materials to be used with thermoplastic as a composite due to its attractive properties such as lightweight and strong. In this paper, flammability properties of this material are evaluated through Underwriters Laboratory 94 Horizontal Burning (UL94 HB), which has been conducted for both controlled and uncontrolled conditions, smoke density and limiting oxygen index tests (LOI). These flammability tests are in compliance with the Federal Aviation Regulation (FAR) requirement. The results from UL94 HB and smoke density tests show that the presence of nanoclays with effective composition of kenaf fiber reinforced ABS has enhanced the burning characteristics of the material by hindering propagation of flame spread over the surface of the material through char formation. Consequently, this decreases the burning rate and produces low amount of smoke during burning. On contrary, through LOI test, this material requires less oxygen to burn when exposed to fire, which hinders the enhancement of burning characteristics. This is due to burning mechanism exhibited by nanoclays that catalyzes barrier formation and flame propagation rate over the surface of the biocomposite material. Overall, these experimental results suggest that this biocomposite material is capable of self-extinguishing and possesses effective fire extinction. The observed novel synergism from the result obtained is promising to be implemented in secondary structures of aircraft with significant benefits such as cost-effective, lightweight and biodegradable self-extinguishing biocomposite.

  15. Flammability limits and explosion characteristics of toluene-nitrous oxide mixtures.

    Science.gov (United States)

    Vandebroek, L; Van den Schoor, F; Verplaetsen, F; Berghmans, J; Winter, H; van't Oost, E

    2005-04-11

    Flammability limits and explosion characteristics of toluene-nitrous oxide mixtures are experimentally determined in an 8l spherical vessel, and are compared with corresponding values of toluene-air mixtures. The experiments, performed at atmospheric pressure and at an initial temperature of 70 degrees C, show that the flammable range of toluene in nitrous oxide (0.25-22.5 mol%) is about three times as wide as the corresponding range of toluene in air (1.3-7.1 mol%). Maximum values of the explosion pressure ratio and the deflagration index, K(G), are clearly higher when nitrous oxide is applied as an oxidizer. This can be attributed to the increased flame temperature and burning velocity of toluene-nitrous oxide flames. Moreover, extremely high values of K(G) for near-stoichiometric mixtures in combination with strong acoustic oscillations in the pressure signals of these mixtures indicate the existence of a flame accelerating mechanism. These phenomena are enhanced when an initial pressure of 6 bara is applied. Finally, when evaluating the lower flammability limit, it was found that pure nitrous oxide decomposes at pressures above 4.5 bara when applying an ignition energy of about 10 J.

  16. Dynamics of flames near the rich-flammability limit of hydrogen-air mixtures

    Science.gov (United States)

    Kailasanath, K.; Ganguly, K.; Patnaik, G.

    1993-01-01

    Flames near the rich-flammability limit of hydrogen-air mixtures are studied using a detailed, time-dependent, one-dimensional Lagrangian model. Results from the numerical simulations indicate that a steady burning velocity is not obtained for very rich hydrogen-air mixtures. As the amount of hydrogen is increased, a damped oscillation is observed in the flame and burning velocities, and then, with further increase in the amount of hydrogen, an undamped oscillation with a complex set of frequencies is observed. Simulations with a simplified one-step irreversible chemical reaction do not show these oscillations, suggesting that chemical kinetics plays a strong role in inducing these oscillations. Further analysis shows that the oscillations are due to a competition for H atoms between chain branching and chain-terminating reactions. Simulations of spherically expanding flames suggest that stretch effects (due to curvature) will cause the oscillations to occur in less rich mixtures than that observed for planar flames. The implications of these oscillations on the rich-flammability limit as well as the role of chemical kinetics in creating a fundamental flammability limit is discussed.

  17. Effect of Zirconium Chloride as a Mordant on Flammability of Dyeing Wool with Madder

    Directory of Open Access Journals (Sweden)

    Arash Almasian

    2015-03-01

    Full Text Available In this research, the effect of zirconium salt as a mordant on flammability of dyeing wool fabric with madder was studied.Wool fabrics were treated with different concentrations of zirconium salt in water solution including 1, 3, 6 and 9% o.w.f. and the dyeing process was carried out on the fabrics in the states before, simultaneously and after-mordanting with madder. Formic acid and oxalic acid were used to generate acidic pH.The chemical characteristics and the changes induced by zirconium were investigated by Fourier-transform infrared spectra (FTIR. Flammability of samples was investigated by horizontal flammability test (HFT. The surfaces of untreated and treated fabrics were evaluated by scanning electron microscopy to observe the morphological changes. The EDX results showed presence of zirconium salt on the surface of wool.The results show that zirconium treated fabrics have a higher weight and lower bending rigidity compared to untreated ones. Furthermore,the zirconium mordant made the wool fabric hydrophobic.

  18. Group-contribution based property estimation and uncertainty analysis for flammability-related properties.

    Science.gov (United States)

    Frutiger, Jérôme; Marcarie, Camille; Abildskov, Jens; Sin, Gürkan

    2016-11-15

    This study presents new group contribution (GC) models for the prediction of Lower and Upper Flammability Limits (LFL and UFL), Flash Point (FP) and Auto Ignition Temperature (AIT) of organic chemicals applying the Marrero/Gani (MG) method. Advanced methods for parameter estimation using robust regression and outlier treatment have been applied to achieve high accuracy. Furthermore, linear error propagation based on covariance matrix of estimated parameters was performed. Therefore, every estimated property value of the flammability-related properties is reported together with its corresponding 95%-confidence interval of the prediction. Compared to existing models the developed ones have a higher accuracy, are simple to apply and provide uncertainty information on the calculated prediction. The average relative error and correlation coefficient are 11.5% and 0.99 for LFL, 15.9% and 0.91 for UFL, 2.0% and 0.99 for FP as well as 6.4% and 0.76 for AIT. Moreover, the temperature-dependence of LFL property was studied. A compound specific proportionality constant (K(LFL)) between LFL and temperature is introduced and an MG GC model to estimate K(LFL) is developed. Overall the ability to predict flammability-related properties including the corresponding uncertainty of the prediction can provide important information for a qualitative and quantitative safety-related risk assessment studies.

  19. Buffer gas-assisted four-wave mixing resonances in alkali vapor excited by a single cw laser

    Science.gov (United States)

    Shmavonyan, Svetlana; Khanbekyan, Aleksandr; Khanbekyan, Alen; Mariotti, Emilio; Papoyan, Aram V.

    2016-12-01

    We report the observation of a fluorescence peak appearing in dilute alkali (Rb, Cs) vapor in the presence of a buffer gas when the cw laser radiation frequency is tuned between the Doppler-broadened hyperfine transition groups of an atomic D2 line. Based on steep laser radiation intensity dependence above the threshold and spectral composition of the observed features corresponding to atomic resonance transitions, we have attributed these features to the buffer gas-assisted four-wave mixing process.

  20. A national assessment of underground natural gas storage: identifying wells with designs likely vulnerable to a single-point-of-failure

    Science.gov (United States)

    Michanowicz, Drew R.; Buonocore, Jonathan J.; Rowland, Sebastian T.; Konschnik, Katherine E.; Goho, Shaun A.; Bernstein, Aaron S.

    2017-05-01

    The leak of processed natural gas (PNG) from October 2015 to February 2016 from the Aliso Canyon storage facility, near Los Angeles, California, was the largest single accidental release of greenhouse gases in US history. The Interagency Task Force on Natural Gas Storage Safety and California regulators recently recommended operators phase out single-point-of-failure (SPF) well designs. Here, we develop a national dataset of UGS well activity in the continental US to assess regulatory data availability and uncertainty, and to assess the prevalence of certain well design deficiencies including single-point-of-failure designs. We identified 14 138 active UGS wells associated with 317 active UGS facilities in 29 states using regulatory and company data. State-level wellbore datasets contained numerous reporting inconsistencies that limited data concatenation. We identified 2715 active UGS wells across 160 facilities that, like the failed well at Aliso Canyon, predated the storage facility, and therefore were not originally designed for gas storage. The majority (88%) of these repurposed wells are located in OH, MI, PA, NY, and WV. Repurposed wells have a median age of 74 years, and the 2694 repurposed wells constructed prior to 1979 are particularly likely to exhibit design-related deficiencies. An estimated 210 active repurposed wells were constructed before 1917—before cement zonal isolation methods were utilized. These wells are located in OH, PA, NY, and WV and represent the highest priority related to potential design deficiencies that could lead to containment loss. This national baseline assessment identifies regulatory data uncertainties, highlights a potentially widespread vulnerability of the natural gas supply chain, and can aid in prioritization and oversight for high-risk wells and facilities.

  1. Ultrasonic nebulization extraction-heating gas flow transfer-headspace single drop microextraction of essential oil from pericarp of Zanthoxylum bungeanum Maxim.

    Science.gov (United States)

    Wei, Shigang; Zhang, Huihui; Wang, Yeqiang; Wang, Lu; Li, Xueyuan; Wang, Yinghua; Zhang, Hanqi; Xu, Xu; Shi, Yuhua

    2011-07-22

    The ultrasonic nebulization extraction-heating gas flow transfer coupled with headspace single drop microextraction (UNE-HGFT-HS-SDME) was developed for the extraction of essential oil from Zanthoxylum bungeanum Maxim. The gas chromatography-mass spectrometry was applied to the determination of the constituents in the essential oil. The contents of the constituents from essential oil obtained by the proposed method were found to be more similar to those obtained by hydro-distillation (HD) than those obtained by ultrasonic nebulization extraction coupled with headspace single drop microextraction (UNE-HS-SDME). The heating gas flow was firstly used in the analysis of the essential oil to transfer the analytes from the headspace to the solvent microdrop. The relative standard deviations for determining the five major constituents were in the range from 1.5 to 6.7%. The proposed method is a fast, sensitive, low cost and small sample consumption method for the determination of the volatile and semivolatile constituents in the plant materials.

  2. Gas gain operations with single photon resolution using an integrating ionization chamber in small-angle X-ray scattering experiments

    CERN Document Server

    Menk, R H; Besch, H J; Walenta, Albert H; Amenitsch, H; Bernstorff, S

    2000-01-01

    In this work a combination of an ionization chamber with one-dimensional spatial resolution and a MicroCAT structure will be presented. Initially, MicroCAT was thought of as a shielding grid (Frisch-grid) but later was used as an active electron amplification device that enables single X-ray photon resolution measurements at low fluxes even with integrating readout electronics. Moreover, the adjustable gas gain that continuously covers the entire range from pure ionization chamber mode up to high gas gains (30000 and more) provides stable operation yielding a huge dynamic range of about 10 sup 8 and more. First measurements on biological samples using small angle X-ray scattering techniques with synchrotron radiation will be presented.

  3. Comparison and evaluation of methods for the determination of flammability limits, applied to methane/hydrogen/air mixtures.

    Science.gov (United States)

    Van den Schoor, F; Hermanns, R T E; van Oijen, J A; Verplaetsen, F; de Goey, L P H

    2008-02-11

    Different methods, both experimental and numerical, to determine the flammability limits are compared and evaluated, exemplified by a determination of the flammability limits of methane/hydrogen/air mixtures for hydrogen fuel molar fractions of 0, 0.2, 0.4 and 0.6, at atmospheric pressure and ambient temperature. Two different experimental methods are used. The first method uses a glass tube with visual observation of the flame, whereas the second method uses a closed spherical vessel with a pressure rise criterion to determine whether flame propagation has occurred. In addition to these experiments, the flammability limits are determined numerically. Unsteady planar and spherically expanding flames are calculated with a one-dimensional flame code with the inclusion of radiation heat loss in the optically thin limit. Comparison of the experimental results with the results of the planar flame calculations shows large differences, especially for lean mixtures. These differences increase with increasing hydrogen content in the fuel. Better agreement with the experimental results is found for the spherically expanding flame calculations. A limiting burning velocity of 5 cm/s is found to predict the upper flammability limit determined with the tube method very well, whereas the limiting flame temperature approach was found to give poorer agreement. Further analysis indicates that the neglect of flame front instabilities is the probable cause of the large differences between experimental and numerical results at the lower flammability limit.

  4. Experimental Analysis of Performance and Emission Parameters of Neem Oil Ethyl Ester and HHO Gas Addition with Neem Oil Ethyl Ester in a Single Cylinder Four Stroke Compression Ignition Engine

    National Research Council Canada - National Science Library

    M Subramanian

    2014-01-01

    .... Present work is focussed on analysing experimentally the performance and emission characteristics of Neem oil biodiesel and addition of HHO gas along with Neem oil biodiesel in a single cylinder...

  5. Gas-liquid selective oxidations with oxygen under explosive conditions in a micro-structured reactor.

    Science.gov (United States)

    Leclerc, Arnaud; Alamé, Mohamad; Schweich, Daniel; Pouteau, Patrick; Delattre, Cyril; de Bellefon, Claude

    2008-05-01

    The gas-liquid oxidation of cyclohexane is performed at high temperature (>200 degrees C) and pressure (up to 25 bar) using pure oxygen in a Pyrex capped silicon etched microreactor which allows convenient screen reaction conditions well above the flammability limit.

  6. Mechanisms of direct detonation initiation via thermal explosion of radiatively heated gas-particles layer

    Science.gov (United States)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Yakovenko, I. S.

    Conceptual approach of detonation wave direct initiation by external radiative heating of microparticles locally suspended in flammable gaseous mixture is proposed. Combustion waves and detonation initiation mechanisms in the congestion regions of microparticles heated by radiation are studied numerically. Necessary criteria on geometrical scales of gas-particles layer and spatial uniformity of particles distribution for successful detonation initiation are formulated.

  7. Online monitoring of trace chlorinated benzenes in flue gas of municipal solid waste incinerator by windowless VUV lamp single photon ionization TOFMS coupled with automatic enrichment system.

    Science.gov (United States)

    Liu, Wei; Jiang, Jichun; Hou, Keyong; Wang, Weiguo; Qi, Yachen; Wang, Yan; Xie, Yuanyuan; Hua, Lei; Li, Haiyang

    2016-12-01

    Chlorinated benzenes are typical precursors and indicators for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) emissions from waste incinerators. Online and real-time monitoring of chlorobenzenes is a challenge due to their low concentration and complex nature of the flue gas. In this work, a continuous online monitoring system was built for detection of trace chlorinated benzenes based on a time-of-flight mass spectrometer (TOFMS). A single photon ionization (SPI) source based on a radiofrequency-excited windowless vacuum ultraviolet (VUV) lamp was developed for the first time to eliminate the signal attenuation resulting from the contamination of magnesium fluoride windows and to avoid the fragment ions. An automatic enrichment system including three parallel Tenax TA adsorption tubes was designed and coupled to the TOFMS to achieve the required ultrahigh sensitivity. The limits of quantitation at 7.65, 5.37 and 6.77pptv were obtained for monochlorobenzene (MCBz), dichlorobenzene (DCBz) and trichlorobenzene (TrCBz), respectively, within a 29-min analytical period. Moreover, this apparatus was applied to continuously online monitor the actual flue gas from a waste incinerator for three months. During this period, the concentrations of MCBz, DCBz and TrCBz detected in the flue gas were in the range of 100-1200, 50-800 and 50-300pptv, respectively. The relative standard deviation (RSD) of the sensitivity for the windowless VUV lamp ion source was 9.71% evaluated by the internal standard benzene over the 3-months flue gas monitoring. These results demonstrated the capability of this method in long-term analysis of the trace chlorinated benzenes in the flue gas. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. A global distribution of the ignitability component of flammability based on climatic drivers

    Science.gov (United States)

    Karali, Anna; Fyllas, Nikolaos M.; Hatzaki, Maria; Giannakopoulos, Christos; Nastos, Panagiotis

    2017-04-01

    Fire regime is the result of complex interactions among ignition, topography, weather and vegetation. Even though the influence of vegetation varies regionally, it remains the only component that can be directly managed in order to reduce the negative impacts of wildland fires. Therefore, reliable information on vegetation flammability is required, making it one of the essential components of fire risk assessment and management. Specific Leaf Area (SLA [cm2 g-1], the ratio of leaf area to leaf dry mass) has received little attention regarding its relationship with ignitability and, thus, flammability. However, recent studies on a regional scale have shown that leaves of higher SLA are more ignitable. Thus, in the framework of the current study, the ignitability, as a function of SLA on global scale, is explored. In order to calculate SLA, a linear regression model combining SLA and climate data has been used (Maire et al., 2015). The climate data used for its calculation include the maximum monthly fractional sunshine duration, the maximum monthly temperature and the number of days with daily mean temperature above 0°C for each grid cell, obtained from the ERA-Interim gridded observations database. Subsequently, the ignitability component of flammability is calculated on a global scale using a bivariate regression relationship with SLA based on experimental burns of leaf materials (Grootemaat et al., 2015). The global distribution of ignitability can subsequently be combined with fire weather index (FWI) values for the development of an integrated index of forest fire vulnerability for the current and future climate, using CMIP5 climate model outputs. This will enable the integration of functional biogeographic data with widely applied fire risk assessment methodologies at regional to global spatial scales.

  9. Single gas chromatography method with nitrogen phosphorus detector for urinary cotinine determination in passive and active smokers

    Directory of Open Access Journals (Sweden)

    Lusiane Malafatti

    2010-12-01

    Full Text Available Nicotine is a major addictive compound in cigarettes and is rapidly and extensively metabolized to several metabolites in humans, including urinary cotinine, considered a biomarker due to its high concentration compared to other metabolites. The aim of this study was to develop a single method for determination of urinary cotinine, in active and passive smokers, by gas chromatography with a nitrogen phosphorus detector (GC-NPD. Urine (5.0 mL was extracted with 1.0 mL of sodium hydroxide 5 mol L-1, 5.0 mL of chloroform, and lidocaine used as the internal standard. Injection volume was 1 μL in GC-NPD. Limit of quantification was 10 ng mL-1. Linearity was evaluated in the ranges 10-1000 ng mL-1 and 500-6000 ng mL-1, with determination coefficients of 0.9986 and 0.9952, respectively. Intra- and inter-assay standard relative deviations were lower than 14.2 %, while inaccuracy (bias was less than +11.9%. The efficiency of extraction was greater than 88.5%. Ruggedness was verified, according to Youden's test. Means of cotinine concentrations observed were 2,980 ng mL-1 for active smokers and 132 ng mL-1, for passive smokers. The results revealed that satisfactory chromatographic separation between the analyte and interferents was obtained with a ZB-1 column. This method is reliable, precise, linear and presented ruggedness in the range evaluated. The results suggest that it can be applied in routine analysis for passive and active smokers, since it is able to quantify a wide range of cotinine concentrations in urine.A nicotina é uma substância presente no cigarro capaz de causar dependência, sendo biotransformada em vários metabólitos nos seres humanos, dentre eles a cotinina urinária, que é considerada um indicador biológico de exposição à nicotina, devido a suas altas concentrações, comparado a outras matrizes. Assim, o objetivo deste estudo foi desenvolver um único método para determinação de cotinina urinária, em amostras de

  10. A new group contribution-based model for estimation of lower flammability limit of pure compounds.

    Science.gov (United States)

    Gharagheizi, Farhad

    2009-10-30

    In the present study, a new method is presented for estimation of lower flammability limit (LFL) of pure compounds. This method is based on a combination of a group contribution method and neural networks. The parameters of the model are the occurrences of a new collection of 105 functional groups. Basing on these 105 functional groups, a feed forward neural network is presented to estimate the LFL of pure compounds. The average absolute deviation error obtained over 1057 pure compounds is 4.62%. Therefore, the model is an accurate model and can be used to predict the LFL of a wide range of pure compounds.

  11. ASTM Committee G-4 metals flammability test program - Data and discussion

    Science.gov (United States)

    Stoltzfus, Joel M.; Homa, John M.; Williams, Ralph E.; Benz, Frank J.

    1988-01-01

    Results of metals flammability tests performed on twenty-six metals in the NASA/White Sands Test Facility are discussed together with the test systems. The promoted combustion and ignition characteristics of these metals are described, and the metals are ranked according to their suitability for use in oxygen systems. In general, alloys with high copper and nickel contents and low iron content were found to rank higher than those that had high iron content, while alloys that had high aluminum content were ranked the lowest.

  12. Up in flames: a flammability assessment of alcohol-based hand sanitizers on common perioperative materials

    OpenAIRE

    Samuel Almengor; W. Patrick Monaghan; Jacksonville, FL

    2015-01-01

    Introduction: The objective of this study was to perform a flammability assessment of alcohol-based hand sanitizers on common perioperative materials. There is an estimated 550–650 surgical fires that occur nationally each year, an instance comparable to that of wrong-site surgery, yet only about 100 operating room fires are reported each year.  The median cost of an OR fire settlement claim is $120,166.  Generation of fire requires the presence of three components, known as the “fire triad”:...

  13. Flammability control in the oxygen environment of the Apollo guidance and navigation equipment

    Science.gov (United States)

    Holley, M. D.; Bachman, S.

    1971-01-01

    The Apollo guidance and navigation (G&N) equipment test program, the redesign philosophy, and the actual equipment modifications that were used to limit burn rates in an environment of 100 percent oxygen at pressures of 6.2 and 16 psia are described. The major approach was a serious basic review of the real function of the nonmetallic materials of concern. The result of this review was that the materials could be replaced, eliminated, or covered by nonflammable metallic materials. Although several low-flammability nonmetallic materials were investigated, the direct approach of cover, eliminate, or replace generally proved to be quicker and more effective.

  14. Making highly flammable liquid wastes of petrochemical works safe by combustion without burners

    Energy Technology Data Exchange (ETDEWEB)

    Shelygin, B.L.; Bakhirev, V.I.; Gudzyuk, V.L.

    1983-11-01

    At the V.I. Lenin Energy Institute in Ivanov a technological program was implementd for combustion of highly flammable bulk wastes (for example, piperylene fractions) of petrochemical enterprises, with a moisture content of under 10% and mechanical admixtures (particles of catalyst dust) of up to 5%, without the use of burners. In devising the program, the results of mathematical theoretical analysis of pre-igniting preparation of substances to make them safe were utilized as well as the experience acquired in burning petroleum sludge in furnaces with bubbling equipment.

  15. Quaternary Ammonium Ionic Liquids as a Less Flammable Electrolyte for Lithium Batteries

    Institute of Scientific and Technical Information of China (English)

    H.Matsumoto; Z.B.Zhou; H.Sakaebe; K.Tatsumi

    2007-01-01

    1 Results Less-flammability is one of the most valuable properties of ionic liquids (ILs) comprised of perfluoroanions such as BF-4,TFSI-([(CF3SO2)2N]-).Recently,such a unique liquid has been expected to use as an electrolyte in order to improve thermal stability and longevity of a lithium secondary battery,which have been increasingly required for an application especially to an electric vehicle and a hybrid car.We previously reported that PI13[TFSI] (PI13: N-methyl-N-propylpiperidinium) could be used ...

  16. A single-pulse shock tube coupled with high-repetition-rate time-of-flight mass spectrometry and gas chromatography for high-temperature gas-phase kinetics studies

    Science.gov (United States)

    Sela, P.; Shu, B.; Aghsaee, M.; Herzler, J.; Welz, O.; Fikri, M.; Schulz, C.

    2016-10-01

    Shock tubes are frequently used to investigate the kinetics of chemical reactions in the gas phase at high temperatures. Conventionally, two complementary arrangements are used where either time-resolved intermediate species measurements are conducted after the initiation of the reaction or where the product composition is determined after rapid initiation and quenching of the reaction through gas-dynamic processes. This paper presents a facility that combines both approaches to determine comprehensive information. A single-pulse shock tube is combined with high-sensitivity gas chromatography/mass spectrometry for product composition and concentration measurement as well as high-repetition-rate time-of-flight mass spectrometry for time-dependent intermediate concentration determination with 10 μs time resolution. Both methods can be applied simultaneously. The arrangement is validated with investigations of the well-documented thermal unimolecular decomposition of cyclohexene towards ethylene and 1,3-butadiene at temperatures between 1000 and 1500 K and pressures ranging from 0.8 to 2.4 bars. The comparison shows that the experimental results for both detections are in very good agreement with each other and with literature data.

  17. Microwave distillation followed by headspace single drop microextraction coupled to gas chromatography-mass spectrometry (GC-MS) for fast analysis of volatile components of Echinophora platyloba DC.

    Science.gov (United States)

    Gholivand, Mohammad Bagher; Abolghasemi, Mir Mahdi; Piryaei, Marzieh; Maassoumi, Sayed Mohammad; Papzan, Abdolhamid

    2013-05-01

    To avoid the traditional and time consuming hydrodistillation, the analyses of volatile components in aerial parts of Echinophora platyloba DC was carried out by a simple microwave distillation followed by headspace single drop microextraction (MD-HS-SDME) coupled to gas chromatography-mass spectrometry (GC-MS). The headspace volatile compounds were collected after irradiation using a single drop of n-heptadecan. The extraction conditions were optimised using the relative peak areas as index. The chemical composition of the MD-HS-SDME extracts was confirmed according to their retention indexes and mass spectra. Fifty-three components were extracted and identified by using the MD-HS-SDME method. E-β-ocimene (53.81%), R-D-decalactone (12.75%), α-pinene (6.43%), n-heptanol (6.27%), β-phellanderne (2.70%) and linalool (1.89%) were the major constituents. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Numerical simulation on vacuum solution heat treatment and gas quenching process of a low rhenium-containing Ni-based single crystal turbine blade

    Directory of Open Access Journals (Sweden)

    Zhe-xin Xu

    2016-11-01

    Full Text Available Numerical heat-transfer and turbulent flow model for an industrial high-pressure gas quenching vacuum furnace was established to simulate the heating, holding and gas fan quenching of a low rhenium-bearing Ni-based single crystal turbine blade. The mesh of simplified furnace model was built using finite volume method and the boundary conditions were set up according to the practical process. Simulation results show that the turbine blade geometry and the mutual shielding among blades have significant influence on the uniformity of the temperature distribution. The temperature distribution at sharp corner, thin wall and corner part is higher than that at thick wall part of blade during heating, and the isotherms show a toroidal line to the center of thick wall. The temperature of sheltered units is lower than that of the remaining part of blade. When there is no shelteration among multiple blades, the temperature distribution for all blades is almost identical. The fluid velocity field, temperature field and cooling curves of the single and multiple turbine blades during gas fan quenching were also simulated. Modeling results indicate that the loading tray, free outlet and the location of turbine blades have important influences on the flow field. The high-speed gas flows out from the nozzle is divided by loading tray, and the free outlet enhanced the two vortex flow at the end of the furnace door. The closer the blade is to the exhaust outlet and the nozzle, the greater the flow velocity is and the more adequate the flow is. The blade geometry has an effect on the cooling for single blade and multiple blades during gas fan quenching, and the effects in double layers differs from that in single layer. For single blade, the cooing rate at thin-walled part is lower than that at thick-walled part, the cooling rate at sharp corner is greater than that at tenon and blade platform, and the temperature at regions close to the internal position is

  19. Anaerobic digestion of kitchen wastes in a single-phased anaerobic sequencing batch reactor(ASBR) with gas-phased absorb of CO2

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bo; HE Zheng-guang; ZHANG Li-li; XU Jian-bo; SHI Hong-zhuan; CAI Wei-min

    2005-01-01

    The performance of the single-stage anaerobic digestion of kitchen wastes was investigated in an anaerobic sequencing batch reactor(ASBR) with gas-phased absorb of CO2. The ASBR was operated at four chemical oxygen demand(COD) loading rates, 2.8,respectively. The operation of the reactor with gas-phased absorb of CO2 was stable in spite of the low pH (2.6-3.9) and high concentration of TS(142 g/L) of input mixture. The output volatile fatty acid(VFA) concentration was between 2.7-4.7 g/L and had no inhibition on the methanogenic microorganism. The reactor without gas-phased absorb of CO2 became acidified when the total COD alkaline will be required to keep pH in the appropriate range for the methanogenic microorganism based on theoretical calculation. Gasphased absorb of CO2 effectively reduced the alkaline consumption, hence avoided excessive cation into the reactor.

  20. Porous and single-crystalline ZnO nanobelts: fabrication with annealing precursor nanobelts, and gas-sensing and optoelectronic performance

    Science.gov (United States)

    Jin, Xiao-Bo; Li, Yi-Xiang; Su, Yao; Guo, Zheng; Gu, Cui-Ping; Huang, Jia-Rui; Meng, Fan-Li; Huang, Xing-Jiu; Li, Min-Qiang; Liu, Jin-Huai

    2016-09-01

    Porous and single-crystalline ZnO nanobelts have been prepared through annealing precursors of ZnSe · 0.5N2H4 well-defined and smooth nanobelts, which have been synthesized via a simple hydrothermal method. The composition and morphology evolutions with the calcination temperatures have been investigated in detail for as-prepared precursor nanobelts, suggesting that they can be easily transformed into ZnO nanobelts by preserving their initial morphology via calcination in air. In contrast, the obtained ZnO nanobelts are densely porous, owing to the thermal decomposition and oxidization of the precursor nanobelts. More importantly, the achieved porous ZnO nanobelts are single-crystalline, different from previously reported ones. Motivated by the intrinsic properties of the porous structure and good electronic transporting ability of single crystals, their gas-sensing performance has been further explored. It is demonstrated that porous ZnO single-crystalline nanobelts exhibit high response and repeatability toward volatile organic compounds, such as ethanol and acetone, with a short response/recovery time. Furthermore, their optoelectronic behaviors indicate that they can be promisingly employed to fabricate photoelectrochemical sensors.

  1. Engineering Calculation Method of Electromagnetic Effect on Oil/Gas Pipelines from 1 000 kV AC Transmission Line Having Single-phase Ground Fault

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wenliang; JIANG Jun; GUO Jian; LU Jiayu

    2012-01-01

    There will be more and more AC transmission lines near oil/gas pipelines in the future.So in order to determine the safe distance between them,simple and effective methods are required for engineers to efficiently evaluate the electromagnetic effect on oil/gas pipelines due to faults of AC transmission lines.In this paper,an easily handled fitting formula is obtained based on multiple calculation results,which is the maximum voltage on the pipeline anticorrosive coating produced by 1 000 kV AC transmission line under single phase ground fault.Although the calculation results obtained from the fitting formula differ from those gained by precise calculation with softwares,the verification of the formula shows that it is applicable for engineering calculation.This research could be applied to evaluate the electromagnetic effect of 1 000 kV AC transmission line under single-phase ground fault on nearby pipelines,as well as to determine the safe distance or the maximum parallel length.

  2. Open and Closed Endotracheal Suctioning and Arterial Blood Gas Values: A Single-Blind Crossover Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    Azam Faraji

    2015-01-01

    Full Text Available Aim. This study was aimed at comparing the effects of the open and closed suctioning techniques on the arterial blood gas values in patients undergoing open-heart surgery. Methods. In a clinical trial, we recruited 42 patients after open-heart surgery in an educational hospital. Each patient randomly underwent both open and closed suctioning. ABGs, PaO2, SaO2, PaCO2, were analyzed before and one, five, and fifteen minutes after each suctioning episode. Results. At first the pressure of oxygen in arterial blood increased; however, this increase in the open technique was greater than that of the closed system (P<0.001. The pressure of oxygen decreased five and fifteen minutes after both suctioning techniques (P<0.05. The trends of carbon dioxide variations after the open and closed techniques were upward and downward, respectively. Moreover, the decrease in the level of oxygen saturation five and fifteen minutes after the open suctioning was greater than that of the closed suctioning technique (P<0.05.  Conclusion. Arterial blood gas disturbances in the closed suctioning technique were less than those of the open technique. Therefore, to eliminate the unwanted effects of endotracheal suctioning on the arterial blood gases, the closed suctioning technique is recommended.

  3. Tests of Flammability of Cotton Fabrics and Expected Skin Burns in Microgravity

    Science.gov (United States)

    Cavanagh, Jane M.; Torvi, David A.; Gabriel, Kamiel S.; Ruff, Gary A.

    2004-01-01

    During a shuttle launch and other portions of space flight, astronauts wear specialized flame resistant clothing. However during most of their missions on board the Space Shuttle or International Space Station, astronauts wear ordinary clothing, such as cotton shirts and pants. As the behaviour of flames is considerably different in microgravity than under earth s gravity, fabrics are expected to burn in a different fashion in microgravity than when tested on earth. There is interest in determining how this change in burning behaviour may affect times to second and third degree burn of human skin, and how the results of standard fabric flammability tests conducted under earth s gravity correlate with the expected fire behaviour of textiles in microgravity. A new experimental apparatus was developed to fit into the Spacecraft Fire Safety Facility (SFSF), which is used on NASA s KC-135 low gravity aircraft. The new apparatus was designed to be similar to the apparatus used in standard vertical flammability tests of fabrics. However, rather than using a laboratory burner, the apparatus uses a hot wire system to ignite 200 mm high by 80 mm wide fabric specimens. Fabric temperatures are measured using thermocouples and/or an infrared imaging system, while flame spread rates are measured using real time observations or video. Heat flux gauges are placed between 7 and 13 mm away from the fabric specimen, so that heat fluxes from the burning fabric to the skin can be estimated, along with predicted times required to produce skin burns.

  4. Swelling of organoclays in styrene. Effect on flammability in polystyrene nanocomposites

    Directory of Open Access Journals (Sweden)

    2010-08-01

    Full Text Available In this work the effect of the compatibility between organoclays and styrene on the flammability of polystyrene/clay nanocomposites obtained through in situ incorporation was investigated. The reactions were carried out by bulk polymerization. The compatibility between organoclays and styrene was inferred from swelling of the organoclay in styrene. The nanocomposites were characterized by X-ray diffraction and Transmission Electron Microscopy. The heat release rate was obtained by Cone Calorimeter and the nanocomposites were tested by UL94 horizontal burn test. Results showed that intercalated and partially exfoliated polystyrene/clay nanocomposites were obtained depending on the swelling behavior of the organoclay in styrene. The nanocomposites submitted to UL94 burning test presented a burning rate faster than the virgin polystyrene (PS, however an increase of the decomposition temperature and an accentuated decrease on the peak of heat release of the nanocomposites were also observed compared to virgin PS. These results indicate that PS/clay nanocomposites, either intercalated or partially exfoliated, reduced the flammability approximately by the same extent, although reduced the ignition resistance of the PS.

  5. Development of organic non-flammable spacecraft potting, encapsulating and conformal coating compounds

    Science.gov (United States)

    Lieberman, S. L.

    1971-01-01

    The overall program objective was to develop a flexible compound which not only functioned in a manned aerospace environment as an effective electrical insulation, but whose flammability characteristics in 16.5 psia, 60% oxygen/40% nitrogen were evidenced by rapid self-extinguishment and minimal thermal (pyrolysis) degradation. The following polymeric matrices were examined in depth: fluoroelastomers, modified fluoroelastomers, silicone RTV's, and modified silicone and fluorosilicone RTV's. Almost none of these systems burned in air, but all burned in 6.2 psia oxygen. Inorganic, organic, and inorganic/organic additives were evaluated in conjunction with these polymers in order to achieve the required survival in the 16.5 psia 60/40 environment. Depending upon formulations, it was possible to achieve nonflammable products when tested in the 1/4 in. x 1/4 in. x 1 in. configuration, even up to and including 16.5 psia oxygen. However, in order to assure this level of flame resistance, it was found necessary to heavily load the matrix with the additives. This resulted in a significant reduction in mechanical properties and large increases in viscosities. Optimization of formulations to obtain a suitable balance between these properties and flammability resistance led to the final selection of Formulation 387 as the primary system.

  6. Structure-flammability relationship study of phosphoester dimers by MLR and PLS

    Directory of Open Access Journals (Sweden)

    Luminita Crisan

    Full Text Available Abstract Polyphosphonates and polyphosphates having good flame retardancy represent an important class of organophosphorus based polymer additives. In this analysis the flammability of 28 previously synthesized polyphosphoesters, modelled as dimmers, was explored using the multiple linear regression (MLR and Partial Least Square (PLS methodology. The statistical quality of the final MLR and PLS models was estimated using the following parameters: the squared correlation coefficient ( r t r a i n i n g 2= 0.917 and 0.976, the training root-mean-square errors (RMSEtr = 0.029 and 0.016 and the leave-seven-out cross-validation correlation coefficient ( q L 7 O 2= 0.748 and 0.881, respectively. External validation was checked for a test set of seven compounds using several criteria. The MLR models had somewhat inferior fitting results. The final MLR and PLS models can be used for the estimation of limiting oxygen index (LOI values of new polyphosphoester structures. The presence of phosphonate groups and increasing molecular branching in an isomeric series favour the dimer flammability.

  7. Mechanical, Thermal Degradation, and Flammability Studies on Surface Modified Sisal Fiber Reinforced Recycled Polypropylene Composites

    Directory of Open Access Journals (Sweden)

    Arun Kumar Gupta

    2012-01-01

    Full Text Available The effect of surface treated sisal fiber on the mechanical, thermal, flammability, and morphological properties of sisal fiber (SF reinforced recycled polypropylene (RPP composites was investigated. The surface of sisal fiber was modified with different chemical reagent such as silane, glycidyl methacrylate (GMA, and O-hydroxybenzene diazonium chloride (OBDC to improve the compatibility with the matrix polymer. The experimental results revealed an improvement in the tensile strength to 11%, 20%, and 31.36% and impact strength to 78.72%, 77%, and 81% for silane, GMA, and OBDC treated sisal fiber reinforced recycled Polypropylene (RPP/SF composites, respectively, as compared to RPP. The thermogravimetric analysis (TGA, differential scanning calorimeter (DSC, and heat deflection temperature (HDT results revealed improved thermal stability as compared with RPP. The flammability behaviour of silane, GMA, and OBDC treated SF/RPP composites was studied by the horizontal burning rate by UL-94. The morphological analysis through scanning electron micrograph (SEM supports improves surface interaction between fiber surface and polymer matrix.

  8. Structure-flammability relationship study of phosphoester dimers by MLR and PLS

    Directory of Open Access Journals (Sweden)

    Luminita Crisan

    2016-01-01

    Full Text Available Abstract Polyphosphonates and polyphosphates having good flame retardancy represent an important class of organophosphorus based polymer additives. In this analysis the flammability of 28 previously synthesized polyphosphoesters, modelled as dimmers, was explored using the multiple linear regression (MLR and Partial Least Square (PLS methodology. The statistical quality of the final MLR and PLS models was estimated using the following parameters: the squared correlation coefficient ( r t r a i n i n g 2= 0.917 and 0.976, the training root-mean-square errors (RMSEtr = 0.029 and 0.016 and the leave-seven-out cross-validation correlation coefficient ( q L 7 O 2= 0.748 and 0.881, respectively. External validation was checked for a test set of seven compounds using several criteria. The MLR models had somewhat inferior fitting results. The final MLR and PLS models can be used for the estimation of limiting oxygen index (LOI values of new polyphosphoester structures. The presence of phosphonate groups and increasing molecular branching in an isomeric series favour the dimer flammability.

  9. Operational safety and post-maintenance gas leak detection in GE frame 9001FA gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Farthing, D.A.; Marley, L.; Lees, J.A. [PowerGen plc, Connah' s Quay Power Station, Deeside (United Kingdom)

    1999-12-01

    The increased use of natural-gas-fuelled combined cycle gas turbine and combined heat and power plants in recent years has been accompanied by the practice of constructing acoustic enclosures around the gas turbines for environmental reasons. This can increase the risk of an explosion if, for any reason, there is a build-up of flammable gas within the enclosure, since there can be a range of possible ignition sources. The UK Health and Safety Executive consider gas leaks within such enclosures to be foreseeable, especially following maintenance. The paper presents a review of operational safety and a leak detection method for the inspection and design of flanged joints within the acoustic enclosures around GE 9001FA gas turbines, providing a practical step towards minimising the risk of explosion due to fuel leakage. (Author)

  10. Analyses of photoinitiated H+CO 2 reactions: Gas phase single-collision conditions and CO 2HBr adducts

    Science.gov (United States)

    Wittig, C.; Engel, Y. M.; Levine, R. D.

    1988-12-01

    Analyses of data obtained under single-collision bulk conditions and from CO 2HBr complexes suggest that with complexes ≈80% of the OHproduct accrues via a mechanism wherein repulsive entrance-channel interactions enhance Br-HOCO † c.m. kinetic energy at the expense of HOCO † internal energy. Resonances are described in which H is localized between Br and OCO until the reactive window opens.

  11. An improved single crystal adsorption calorimeter for determining gas adsorption and reaction energies on complex model catalysts

    Science.gov (United States)

    Fischer-Wolfarth, Jan-Henrik; Hartmann, Jens; Farmer, Jason A.; Flores-Camacho, J. Manuel; Campbell, Charles T.; Schauermann, Swetlana; Freund, Hans-Joachim

    2011-02-01

    A new ultrahigh vacuum microcalorimeter for measuring heats of adsorption and adsorption-induced surface reactions on complex single crystal-based model surfaces is described. It has been specifically designed to study the interaction of gaseous molecules with well-defined model catalysts consisting of metal nanoparticles supported on single crystal surfaces or epitaxial thin oxide films grown on single crystals. The detection principle is based on the previously described measurement of the temperature rise upon adsorption of gaseous molecules by use of a pyroelectric polymer ribbon, which is brought into mechanical/thermal contact with the back side of the thin single crystal. The instrument includes (i) a preparation chamber providing the required equipment to prepare supported model catalysts involving well-defined nanoparticles on clean single crystal surfaces and to characterize them using surface analysis techniques and in situ reflectivity measurements and (ii) the adsorption/reaction chamber containing a molecular beam, a pyroelectric heat detector, and calibration tools for determining the absolute reactant fluxes and adsorption heats. The molecular beam is produced by a differentially pumped source based on a multichannel array capable of providing variable fluxes of both high and low vapor pressure gaseous molecules in the range of 0.005-1.5 × 1015 molecules cm-2 s-1 and is modulated by means of the computer-controlled chopper with the shortest pulse length of 150 ms. The calorimetric measurements of adsorption and reaction heats can be performed in a broad temperature range from 100 to 300 K. A novel vibrational isolation method for the pyroelectric detector is introduced for the reduction of acoustic noise. The detector shows a pulse-to-pulse standard deviation ≤15 nJ when heat pulses in the range of 190-3600 nJ are applied to the sample surface with a chopped laser. Particularly for CO adsorption on Pt(111), the energy input of 15 nJ (or 120 nJ cm

  12. Single crystal to single crystal (SC-to-SC) transformation from a nonporous to porous metal-organic framework and its application potential in gas adsorption and Suzuki coupling reaction through postmodification.

    Science.gov (United States)

    Sen, Rupam; Saha, Debraj; Koner, Subratanath; Brandão, Paula; Lin, Zhi

    2015-04-07

    A new amino-functionalized strontium-carboxylate-based metal-organic framework (MOF) has been synthesized that undergoes single crystal to single crystal (SC-to-SC) transformation upon desolvation. Both structures have been characterized by single-crystal X-ray analysis. The desolvated structure shows an interesting 3D porous structure with pendent -NH2 groups inside the pore wall, whereas the solvated compound possesses a nonporous structure with DMF molecules on the metal centers. The amino group was postmodified through Schiff base condensation by pyridine-2-carboxaldehyde and palladium was anchored on that site. The modified framework has been utilized for the Suzuki cross-coupling reaction. The compound shows high activity towards the C-C cross-coupling reaction with good yields and turnover frequencies. Gas adsorption studies showed that the desolvated compound had permanent porosity and was microporous in nature with a BET surface area of 2052 m(2)  g(-1). The material also possesses good CO2 (8 wt %) and H2 (1.87 wt %) adsorption capabilities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Evaluation of Reformer Produced Synthesis Gas for Emissions Reductions in Natural Gas Reciprocating Engines

    Energy Technology Data Exchange (ETDEWEB)

    Mark Scotto

    2010-05-30

    Rolls-Royce Fuel Cell Systems (US) Inc. (RRFCS) has developed a system that produces synthesis gas from air and natural gas. A near-term application being considered for this technology is synthesis gas injection into reciprocating engines for reducing NO{sub x} emissions. A proof of concept study using bottled synthesis gas and a two-stroke reciprocating engine showed that injecting small amounts of high-flammable content synthesis gas significantly improved combustion stability and enabled leaner engine operation resulting in over 44% reduction in NO{sub x} emissions. The actual NO{sub x} reduction that could be achieved in the field is expected to be engine specific, and in many cases may be even greater. RRFCS demonstrated that its synthesis gas generator could produce synthesis gas with the flammable content that was successfully used in the engine testing. An economic analysis of the synthesis gas approach estimates that its initial capital cost and yearly operating cost are less than half that of a competing NO{sub x} reduction technology, Selective Catalytic Reduction. The next step in developing the technology is an integrated test of the synthesis gas generator with an engine to obtain reliability data for system components and to confirm operating cost. RRFCS is actively pursuing opportunities to perform the integrated test. A successful integrated test would demonstrate the technology as a low-cost option to reduce NO{sub x} emissions from approximately 6,000 existing two-stroke, natural gas-fired reciprocating engines used on natural gas pipelines in North America. NO{sub x} emissions reduction made possible at a reasonable price by this synthesis gas technology, if implemented on 25% of these engines, would be on the order of 25,000 tons/year.

  14. Different catalytic effects of a single water molecule: the gas-phase reaction of formic acid with hydroxyl radical in water vapor.

    Science.gov (United States)

    Anglada, Josep M; Gonzalez, Javier

    2009-12-07

    The effect of a single water molecule on the reaction mechanism of the gas-phase reaction between formic acid and the hydroxyl radical was investigated with high-level quantum mechanical calculations using DFT-B3LYP, MP2 and CCSD(T) theoretical approaches in concert with the 6-311+G(2df,2p) and aug-cc-pVTZ basis sets. The reaction between HCOOH and HO has a very complex mechanism involving a proton-coupled electron transfer process (pcet), two hydrogen-atom transfer reactions (hat) and a double proton transfer process (dpt). The hydroxyl radical predominantly abstracts the acidic hydrogen of formic acid through a pcet mechanism. A single water molecule affects each one of these reaction mechanisms in different ways, depending on the way the water interacts. Very interesting is also the fact that our calculations predict that the participation of a single water molecule results in the abstraction of the formyl hydrogen of formic acid through a hydrogen atom transfer process (hat).

  15. Analysis of honeybush tea (Cyclopia spp.) volatiles by comprehensive two-dimensional gas chromatography using a single-stage thermal modulator.

    Science.gov (United States)

    Ntlhokwe, Gaalebalwe; Tredoux, Andreas G J; Górecki, Tadeusz; Edwards, Matthew; Vestner, Jochen; Muller, Magdalena; Erasmus, Lené; Joubert, Elizabeth; Christel Cronje, J; de Villiers, André

    2017-07-01

    The applicability of comprehensive two-dimensional gas chromatography (GC×GC) using a single-stage thermal modulator was explored for the analysis of honeybush tea (Cyclopia spp.) volatile compounds. Headspace solid phase micro-extraction (HS-SPME) was used in combination with GC×GC separation on a non-polar × polar column set with flame ionisation (FID) detection for the analysis of fermented Cyclopia maculata, Cyclopia subternata and Cyclopia genistoides tea infusions of a single harvest season. Method optimisation entailed evaluation of the effects of several experimental parameters on the performance of the modulator, the choice of columns in both dimensions, as well as the HS-SPME extraction fibre. Eighty-four volatile compounds were identified by co-injection of reference standards. Principal component analysis (PCA) showed clear differentiation between the species based on their volatile profiles. Due to the highly reproducible separations obtained using the single-stage thermal modulator, multivariate data analysis was simplified. The results demonstrate both the complexity of honeybush volatile profiles and the potential of GC×GC separation in combination with suitable data analysis techniques for the investigation of the relationship between sensory properties and volatile composition of these products. The developed method therefore offers a fast and inexpensive methodology for the profiling of honeybush tea volatiles. Graphical abstract Surface plot obtained for the GC×GC-FID analysis of honeybush tea volatiles.

  16. Vapor and gas sampling of single-shell tank 241-B-102 using the in situ vapor sampling system

    Energy Technology Data Exchange (ETDEWEB)

    Lockrem, L.L.

    1997-08-05

    The Vapor Issue Resolution Program tasked the Vapor Team (the team) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-B-102. This document presents sampling data resulting from the April 18, 1996 sampling of SST 241-B-102. Analytical results will be presented in a separate report issued by Pacific Northwest National Laboratory (PNNL), which supplied and analyzed the sampling media. The team, consisting of Sampling and Mobile Laboratories (SML) and Special Analytical Studies (SAS) personnel, used the vapor sampling system (VSS) to collect representative samples of the air, gases, and vapors from the headspace of SST 241-B-102 with sorbent traps and SUMMA canisters.

  17. Methods development for measuring and classifying flammability/combustibility of refrigerants. Interim report, Task 1 -- Annotated bibliography and summary

    Energy Technology Data Exchange (ETDEWEB)

    Heinonen, E.W.; Tapscott, R.E. [New Mexico Univ., Albuquerque, NM (United States). Center for Global Enviromental Technology

    1994-06-01

    For Task 1 of the flammable refrigerant methods development contract, NMERI performed a literature search to identify references on the flammability of refrigerants. A database to store a bibliographic record of the literature search was then developed. This database is contained in the Microsoft Access{reg_sign} relational database management system for Windows{trademark}. Searches for applicable sources were made on-line using the STN{reg_sign} scientific and technical network; off-line using the National Technical Information Service (NTIS) database; WorldCat CD-rom database; the University of New Mexico library search; the Air-Conditioning and Refrigeration institute (ARI) Refrigerant Database; and personal contacts. Three specific areas were searched: refrigerant properties, flammability test methods, and ignition technology. Many of the articles retrieved fall into multiple categories. Ignition technology was included as a separate category because of the importance of the ignition process to flammability and the vast amount of information available on ignition of gaseous fuels, especially hydrocarbons. Over 90 separate references have been entered into the database. Two separate report formats have been developed to display the results of the literature search. Appendix B is the short report format--without abstract, while Appendix C is the long format--with abstract.

  18. Deep Sludge Gas Release Event Analytical Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Sams, Terry L.

    2013-08-15

    Long Abstract. Full Text. The purpose of the Deep Sludge Gas Release Event Analytical Evaluation (DSGRE-AE) is to evaluate the postulated hypothesis that a hydrogen GRE may occur in Hanford tanks containing waste sludges at levels greater than previously experienced. There is a need to understand gas retention and release hazards in sludge beds which are 200 -300 inches deep. These sludge beds are deeper than historical Hanford sludge waste beds, and are created when waste is retrieved from older single-shell tanks (SST) and transferred to newer double-shell tanks (DST).Retrieval of waste from SSTs reduces the risk to the environment from leakage or potential leakage of waste into the ground from these tanks. However, the possibility of an energetic event (flammable gas accident) in the retrieval receiver DST is worse than slow leakage. Lines of inquiry, therefore, are (1) can sludge waste be stored safely in deep beds; (2) can gas release events (GRE) be prevented by periodically degassing the sludge (e.g., mixer pump); or (3) does the retrieval strategy need to be altered to limit sludge bed height by retrieving into additional DSTs? The scope of this effort is to provide expert advice on whether or not to move forward with the generation of deep beds of sludge through retrieval of C-Farm tanks. Evaluation of possible mitigation methods (e.g., using mixer pumps to release gas, retrieving into an additional DST) are being evaluated by a second team and are not discussed in this report. While available data and engineering judgment indicate that increased gas retention (retained gas fraction) in DST sludge at depths resulting from the completion of SST 241-C Tank Farm retrievals is not expected and, even if gas releases were to occur, they would be small and local, a positive USQ was declared (Occurrence Report EM-RP--WRPS-TANKFARM-2012-0014, "Potential Exists for a Large Spontaneous Gas Release Event in Deep Settled Waste Sludge"). The purpose of this technical

  19. Gas Flow and Electric Field Characterization in Plasma Jets for Biomedical Applications: From Single Jet to Multi Jet Arrays

    Science.gov (United States)

    Robert, Eric

    2015-09-01

    This work reports first on time-resolved measurement of longitudinal and radial electric fields (EF) associated with plasma propagation in dielectric capillaries. Plasma propagation occurs in a region where longitudinal EF exists ahead the ionization front position revealed from plasma emission with ICCD measurement. The ionization front propagation induces the sudden rise of a radial EF component. Both of these EF components have a few kV/cm in amplitude for helium or neon plasmas. Their amplitude is kept almost constant along a few tens of cm long capillary. The key role of the voltage pulse polarity and the drastic impact of the presence of a target in front of the plasma jet are discussed from Schlieren images. All these experimental measurements are in excellent agreement with model calculations which are used to infer EF data on capillary axis. EF diagnostics in the plasma plume in the free jet mode but also in contact with various targets is proposed. The combination of intense transient EF, both of ns and µs duration, together with significant transient reactive species generation during plasma jet treatments may be reconsidered. Typical EF amplitudes likely to induce electrostimulation, electroporation are indeed probably achieved in many in vivo protocols. Stimulation of tissue oxygenation, blood flow rate modulation and more recently immune system triggering may be examples where EF could play a significant role. The second part of this work is dedicated to the development of multi jets, using two different setups, based on a single plasma source. Plasma splitting in dielectric tubes drilled with sub millimetric orifices, but also plasma transfer across metallic tubes equipped with such orifices are analyzed from ICCD imaging and time resolved EF measurements. This allows for the design of plasma jet arrays but also emphasizes the necessity to account for voltage pulse polarity, target potential status, consecutive helium flow modulation and

  20. Integrated development and industrial application of high sour natural gas purification technology

    Institute of Scientific and Technical Information of China (English)

    Sun Lili

    2013-01-01

    Aiming at acute characteristics of flammability,explosibility,causticity and leakiness of high sour nat-ural gas,giving full consideration to local natural conditions in Sichuan Province and starting with purification pro-cess,the paper analyzed process configurations,energy utilization and conservation,safety and environment pro-tection measures. The integrated technology and engineering scheme for high sour natural gas purification was es-tablished and successfully used in industrial application.

  1. Evaluation of Gas Retention in Waste Simulants: Tall Column Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Schonewill, Philip P.; Gauglitz, Phillip A.; Shimskey, Rick W.; Denslow, Kayte M.; Powell, Michael R.; Boeringa, Gregory K.; Bontha, Jagannadha R.; Karri, Naveen K.; Fifield, Leonard S.; Tran, Diana N.; Sande, Susan; Heldebrant, David J.; Meacham, Joseph E.; Smet, Dave; Bryan, Wesley E.; Calmus, Ronald B.

    2014-05-16

    Gas generation in Hanford’s underground waste storage tanks can lead to gas accumulation within the layer of settled solids (sludge) at the tank bottom. The gas, which typically has hydrogen as the major component together with other flammable species, is formed principally by radiation-driven chemical reactions. Accumulation of these gases within the sludge in a waste tank is undesirable and limits the amount of tank volume for waste storage. Further, accumulation of large amounts of gas in the sludge may potentially result in an unacceptable release of the accumulated gas if the sludge-layer density is reduced to less than that of the overlying sludge or that of the supernatant liquid. Rapid release of large amounts of flammable gases could endanger personnel and equipment near the tank. For this reason, a thorough understanding of the circumstances that can lead to a potentially problematic gas accumulation in sludge layers is needed. To respond to this need, the Deep Sludge Gas Release Event Program (DSGREP) was commissioned to examine gas release behavior in sludges.

  2. [Coupling of gas chromatography with single photon ionization time-of-flight mass spectrometry and its application to characterization of compounds in diesel].

    Science.gov (United States)

    Xie, Yuanyuan; Hua, Lei; Chen, Ping; Hou, Keyong; Jiang, Jichun; Wang, Yan; Li, Haiyang

    2015-02-01

    A novel analytical method coupling gas chromatography (GC) with single photon ionization time-of-flight mass spectrometry (SPI-TOF MS) has been developed. First of all, a double-wall-tube transfer line was built to combine GC with SPI-TOF MS, which realized seamless connection between GC and SPI ion source. Based on this, standard n-pentadecane and benzene/toluene/xylene standard gas mixtures were used to study important voltage parameters of the ion source. After the optimization of the ion source voltages, pure molecular ion peaks of the analytes were obtained in the mass spectra and qualitative analysis of different kinds of organic compounds were eventually realized rapidly and accurately. At last, GC/SPI-TOF MS was applied to the characterization of volatile and semvolatile organic compounds in diesel and two-dimensional spectra of GC×SPI-TOF MS were obtained. Without complicated spectra interpretation and data processing, volatile and semi-volatile organic compounds in diesel have been classified qualitatively by ion mass-to-charge ratio (m/z) in SPI mass spectra, including aliphatic compounds, aromatic compounds and nitrogen-containing compounds with low concentration such as benzopyrroles. Isomeric compounds in diesel were separated and identified by retention times of chromatographic peaks. The results indicate that the proposed analytical method of GC/SPI-TOF MS is suitable for the characterization of complicated samples such as diesel and environmental pollutants with easy operation and high efficiency.

  3. Stability of hybrid modes of a single-component electron plasma containing an admixture of background gas ions

    Science.gov (United States)

    Yeliseyev, Yu. N.

    2014-05-01

    The spectrum of eigenmodes of a waveguide completely filled with a cold electron plasma containing a small admixture of ions produced due to electron-impact ionization of background gas atoms is calculated numerically. The calculations were performed within the entire range of allowable values of the radial electric and longitudinal magnetic fields for both magnetized and unmagnetized ions by using the earlier derived nonlocal dispersion relation [Plasma Phys. Rep. 36, 563 (2010)]. The spectrum consists of three families of electron modes with frequencies equal to the Doppler-shifted upper and lower hybrid frequencies and modified ion cyclotron (MIC) modes. When the Doppler shift caused by electron rotation in the crossed electric and magnetic fields compensates for the hybrid frequency, the electron modes become low-frequency modes and interact with the ion modes. For m = 1, only the lower hybrid modes can be low-frequency ones, whereas at m ≥ 2, both lower and upper hybrid modes can be low-frequency ones. The spectrum of modes having the azimuthal number m = 2 is thoroughly analyzed. It is shown that, in this case, the lower hybrid modes behave similar to the m = 1 modes. The dispersion curves of the upper hybrid modes intersect with all harmonics of the MIC frequency (positive, negative, and zero) and are unstable in the vicinities of the intersections. The maximum value of the instability growth rate is several times higher than the ion plasma frequency. The MIC modes are unstable within a wide range of the field strengths, and their growth rates are two orders of magnitude slower. Instabilities are caused by the relative motion of electrons and ions (the transverse current) and the anisotropy of the ion distribution function.

  4. Responding to Terrorist Incidents in Your Community: Flammable-Liquid Fire Fighting Techniques for Municipal and Rural Firefighters

    Energy Technology Data Exchange (ETDEWEB)

    Denise Baclawski

    2010-03-08

    The University of Nevada, Reno Fire Science Academy (FSA) applied for grant funding to develop and deliver programs for municipal, rural, and volunteer firefighters. The FSA specializes in preparing responders for a variety of emergency events, including flammable liquid fires resulting from accidents, intentional acts, or natural disasters. Live fire training on full scale burnable props is the hallmark of FSA training, allowing responders to practice critical skills in a realistic, yet safe environment. Unfortunately, flammable liquid live fire training is often not accessible to municipal, rural, or volunteer firefighters due to limited department training budgets, even though most department personnel will be exposed to flammable liquid fire incidents during the course of their careers. In response to this training need, the FSA developed a course during the first year of the grant (Year One), Responding to Terrorist Incidents in Your Community: Flammable-Liquid Fire Fighting Techniques for Municipal and Rural Firefighters. During the three years of the grant, a total of 2,029 emergency responders received this training. In Year Three, two new courses, a train-the-trainer for Responding to Terrorist Incidents in Your Community and Management of Large-Scale Disasters for Public Officials were developed and pilot tested during the Real-World Disaster Management Conference held at the FSA in June of 2007. Two research projects were conducted during Years Two and Three. The first, conducted over a two year period, evaluated student surveys regarding the value of the flammable liquids training received. The second was a needs assessment conducted for rural Nevada. Both projects provided important feedback and a basis for curricula development and improvements.

  5. Increasing the instrumental throughput of gas chromatography method using multiple injections in a single experimental run: application in determination of friedelan-3-ol and friedelin in Maytenus ilicifolia.

    Science.gov (United States)

    Vistuba, Jacqueline Pereira; Piovezan, Marcel; Pizzolatti, Moacir Geraldo; Rebelo, Andrey Martinez; Azevedo, Mônia Stremel; Vitali, Luciano; Costa, Ana Carolina Oliveira; Amadeu Micke, Gustavo

    2013-01-25

    The aim of this study was to develop a separation method using multiple injections in a single experimental run (MISER) employing gas chromatography with flame ionization detection (GC-FID) for the first time, without instrument modification, to increase the instrumental throughput. The method was applied to the determination of the triterpenes friedelan-3-ol and friedelin in a plant extract obtained from Maytenus ilicifolia leaves. The column used in the chromatography system was a ZB-50 (30 m × 0.25 mm × 0.15 μm) with 50% phenyl-50% methyl-polysiloxane. The samples (1.0 μL) were injected using the split mode (1:90), with the injector at 280 °C and FID detector at 320 °C. The column temperature was programmed to isothermal mode at 300°C. Helium was used as the carrier gas with a constant flow of 1.5 mL min(-1). It was possible to perform three injections in the same run using the MISER method. An increase in the instrumental throughput by a factor of around 2.6 was observed when the use of multiple injections was compared with the single injection method. This method showed good linearity for both analytes with R(2)>0.99 and the values for the limit of detection were 0.24 mg L(-1) and 0.44 mg L(-1), for friedelan-3-ol and friedelin, respectively. Furthermore, the values for the limits of quantification were 0.79 mg L(-1) for friedelan-3-ol and 1.16 mg L(-1) for friedelin. The proposed method has potential for other GC applications, allowing an increase in the instrumental throughput of the methods by applying this separation technique.

  6. Influence of dispersion degree of water drops on efficiency of extinguishing of flammable liquids

    Directory of Open Access Journals (Sweden)

    Korolchenko Dmitriy

    2016-01-01

    Full Text Available Depending on the size of water drops, process of fire extinguishing is focused either in a zone of combustion or on a burning liquid surface. This article considers two alternate solutions of a heat balance equation. The first solution allows us to trace decrease of temperature of a flammable liquid (FL surface to a temperature lower than fuel flash point at which combustion is stopped. And the second solution allows us to analyze decrease of burnout rate to a negligible value at which steam-air mixture becomes nonflammable. As a result of solve of a heat balance equation it was made the following conclusion: water drops which size is equal to 100 μm will completely evaporate in a zone of combustion with extent of 1 m if the flying speed of drops is even 16 mps (acc. to Stokes v = 3 mps; whereas drops of larger size will evaporate only partially.

  7. Flammability of polypropylene/organoclay nanocomposites; Inflamabilidade de nanocompositos de polipropileno/argila organofilica

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Tatianny Soares; Barbosa, Renata, E-mail: tsaeng3@yahoo.com.br [Universidade Federal do Piaui (UFPI), Teresina (Brazil); Carvalho, Laura Hecker de [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Canedo, Eduardo Luis [Instituto de Tecnologia de Pernambuco, Recife (Brazil)

    2014-11-01

    The flammabilities of nanocomposites made with three polypropylene grades (homo and copolymers) with 5 wt % of organoclay (Cloisite 20A), 5 or 15 wt % of maleated polypropylene as compatibilizer, and 0, 0.5 or 1 wt % of cis-13-docosenamide (Erucamide) as co-intercalant, were studied using the horizontal burning test UL94HB. Masterbatches prepared in an internal mixer were diluted in the polypropylene matrix using a corotating twin-screw extruder, with different screw configurations and operating at 240 or 480 rpm. Results indicate that the high burning rate of the composites was not affected by the processing conditions. For all formulations was observed a significant reduction in smoke release, lack of dripping and the formation of a char surface layer, that protected the core of the samples. (author)

  8. Upward Flame Propagation and Wire Insulation Flammability: 2006 Round Robin Data Analysis

    Science.gov (United States)

    Hirsch, David B.

    2007-01-01

    This viewgraph document reviews test results from tests of different material used for wire insulation for flame propagation and flammability. The presentation focused on investigating data variability both within and between laboratories; evaluated the between-laboratory consistency through consistency statistic h, which indicates how one laboratory s cell average compares with averages from other labs; evaluated the within-laboratory consistency through the consistency statistic k, which is an indicator of how one laboratory s within-laboratory variability compares with the variability of other labs combined; and extreme results were tested to determine whether they resulted by chance or from nonrandom causes (human error, instrument calibration shift, non-adherence to procedures, etc.)

  9. Flammability properties of polypropylene containing montmorillonite and some of silicon compounds

    Directory of Open Access Journals (Sweden)

    A.A. Younis

    2017-03-01

    Full Text Available New polypropylene (PP blends were prepared using phenyltrimethoxysilane (PTMS, glycidoxypropyltrimethoxysilane (GPTMS and potassium-montmorillonite (K-MMT. Polymers A (K-MMT/PTMS, B (MMT/GPTMS and C (modified-MMT were prepared using sol-gel technique then incorporated in the PP matrix by different concentrations. Fourier transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, and differential scanning calorimeter (DSC were used to investigate the structure and thermal stability. The mechanical properties (tensile strength/TS and elongation/% were measured. The flame-retardant properties of the unblended and blended (PP/A, PP/B and PP/C were estimated by limiting oxygen index (LOI, flame chamber (UL/94 and oxygen bomb calorimeter (OBC tests, whereas the thermal stabilities were investigated using TGA were carried flammability out to detect the properties of the blended PP.

  10. Experimental Studies on the Flammability and Fire Hazards of Photovoltaic Modules

    Directory of Open Access Journals (Sweden)

    Hong-Yun Yang

    2015-07-01

    Full Text Available Many of the photovoltaic (PV systems on buildings are of sufficiently high voltages, with potential to cause or promote fires. However, research about photovoltaic fires is insufficient. This paper focuses on the flammability and fire hazards of photovoltaic modules. Bench-scale experiments based on polycrystalline silicon PV modules have been conducted using a cone calorimeter. Several parameters including ignition time (tig, mass loss, heat release rate (HRR, carbon monoxide (CO and carbon dioxide (CO2 concentration, were investigated. The fire behaviours, fire hazards and toxicity of gases released by PV modules are assessed based on experimental results. The results show that PV modules under tests are inflammable with the critical heat flux of 26 kW/m2. This work will lead to better understanding on photovoltaic fires and how to help authorities determine the appropriate fire safety provisions for controlling photovoltaic fires.

  11. A highly conductive, non-flammable polymer–nanoparticle hybrid electrolyte

    KAUST Repository

    Agrawal, Akanksha

    2015-01-01

    © 2015 The Royal Society of Chemistry. We report on the physical properties of lithium-ion conducting nanoparticle-polymer hybrid electrolytes created by dispersing bidisperse mixtures of polyethylene glycol (PEG)-functionalized silica nanoparticles in an aprotic liquid host. At high particle contents, we find that the ionic conductivity is a non-monotonic function of the fraction of larger particles xL in the mixtures, and that for the nearly symmetric case xL ≈ 0.5 (i.e. equal volume fraction of small and large particles), the room temperature ionic conductivity is nearly ten-times larger than in similar nanoparticle hybrid electrolytes comprised of the pure small (xL ≈ 0) or large (xL ≈ 1) particle components. Complementary trends are seen in the activation energy for ion migration and effective tortuosity of the electrolytes, which both exhibit minima near xL ≈ 0.5. Characterization of the electrolytes by dynamic rheology reveals that the maximum conductivity coincides with a distinct transition in soft glassy properties from a jammed to partially jammed and back to jammed state, as the fraction of large particles is increased from 0 to 1. This finding implies that the conductivity enhancement arises from purely entropic loss of correlation between nanoparticle centers arising from particle size dispersity. As a consequence of these physics, it is now possible to create hybrid electrolytes with MPa elastic moduli and mS cm-1 ionic conductivity levels at room temperature using common aprotic liquid media as the electrolyte solvent. Remarkably, we also find that even in highly flammable liquid media, the bidisperse nanoparticle hybrid electrolytes can be formulated to exhibit low or no flammability without compromising their favorable room temperature ionic conductivity and mechanical properties.

  12. Role of single-point mutations and deletions on transition temperatures in ideal proteinogenic heteropolymer chains in the gas phase.

    Science.gov (United States)

    Olivares-Quiroz, L

    2016-07-01

    A coarse-grained statistical mechanics-based model for ideal heteropolymer proteinogenic chains of non-interacting residues is presented in terms of the size K of the chain and the set of helical propensities [Formula: see text] associated with each residue j along the chain. For this model, we provide an algorithm to compute the degeneracy tensor [Formula: see text] associated with energy level [Formula: see text] where [Formula: see text] is the number of residues with a native contact in a given conformation. From these results, we calculate the equilibrium partition function [Formula: see text] and characteristic temperature [Formula: see text] at which a transition from a low to a high entropy states is observed. The formalism is applied to analyze the effect on characteristic temperatures [Formula: see text] of single-point mutations and deletions of specific amino acids [Formula: see text] along the chain. Two probe systems are considered. First, we address the case of a random heteropolymer of size K and given helical propensities [Formula: see text] on a conformational phase space. Second, we focus our attention to a particular set of neuropentapeptides, [Met-5] and [Leu-5] enkephalins whose thermodynamic stability is a key feature on their coupling to [Formula: see text] and [Formula: see text] receptors and the triggering of biochemical responses.

  13. The Application of Gas Dwell Time Control for Rapid Single Wall Carbon Nanotube Forest Synthesis to Acetylene Feedstock

    Directory of Open Access Journals (Sweden)

    Naoyuki Matsumoto

    2015-07-01

    Full Text Available One aspect of carbon nanotube (CNT synthesis that remains an obstacle to realize industrial mass production is the growth efficiency. Many approaches have been reported to improve the efficiency, either by lengthening the catalyst lifetime or by increasing the growth rate. We investigated the applicability of dwell time and carbon flux control to optimize yield, growth rate, and catalyst lifetime of water-assisted chemical vapor deposition of single-walled carbon nanotube (SWCNT forests using acetylene as a carbon feedstock. Our results show that although acetylene is a precursor to CNT synthesis and possesses a high reactivity, the SWCNT forest growth efficiency is highly sensitive to dwell time and carbon flux similar to ethylene. Through a systematic study spanning a wide range of dwell time and carbon flux levels, the relationship of the height, growth rate, and catalyst lifetime is found. Further, for the optimum conditions for 10 min growth, SWCNT forests with ~2500 μm height, ~350 μm/min initial growth rates and extended lifetimes could be achieved by increasing the dwell time to ~5 s, demonstrating the generality of dwell time control to highly reactive gases.

  14. The Application of Gas Dwell Time Control for Rapid Single Wall Carbon Nanotube Forest Synthesis to Acetylene Feedstock

    Science.gov (United States)

    Matsumoto, Naoyuki; Oshima, Azusa; Sakurai, Shunsuke; Yamada, Takeo; Yumura, Motoo; Hata, Kenji; Futaba, Don N.

    2015-01-01

    One aspect of carbon nanotube (CNT) synthesis that remains an obstacle to realize industrial mass production is the growth efficiency. Many approaches have been reported to improve the efficiency, either by lengthening the catalyst lifetime or by increasing the growth rate. We investigated the applicability of dwell time and carbon flux control to optimize yield, growth rate, and catalyst lifetime of water-assisted chemical vapor deposition of single-walled carbon nanotube (SWCNT) forests using acetylene as a carbon feedstock. Our results show that although acetylene is a precursor to CNT synthesis and possesses a high reactivity, the SWCNT forest growth efficiency is highly sensitive to dwell time and carbon flux similar to ethylene. Through a systematic study spanning a wide range of dwell time and carbon flux levels, the relationship of the height, growth rate, and catalyst lifetime is found. Further, for the optimum conditions for 10 min growth, SWCNT forests with ~2500 μm height, ~350 μm/min initial growth rates and extended lifetimes could be achieved by increasing the dwell time to ~5 s, demonstrating the generality of dwell time control to highly reactive gases.

  15. Significant Gas Adsorption and Catalytic Performance by a Robust Cu(II) -MOF Derived through Single-Crystal to Single-Crystal Transmetalation of a Thermally Less-Stable Zn(II) -MOF.

    Science.gov (United States)

    Pal, Tapan K; De, Dinesh; Neogi, Subhadip; Pachfule, Pradip; Senthilkumar, S; Xu, Qiang; Bharadwaj, Parimal K

    2015-12-21

    By using a bent tetracarboxylic acid ligand that incorporates a pendent-NH2 functional group, a 3D Zn(II)-framework (1) based on Zn2 (CO2)4 secondary building units and Zn12 (CO2)24 supramolecular building blocks has been synthesized. Framework 1 is thermally less stable, which precludes its application as a porous framework for gas adsorption or catalytic studies. This framework undergoes single-crystal to single-crystal transmetalation to give isostructural 1Cu. Unlike 1, the Cu(II) analogue is very stable and can be activated by removing metal-bound lattice solvent molecules by heating to afford 1Cu'. The activated 1Cu' exhibits excellent H2 storage (2.29 wt%) at 77 K and a high 32.1 wt% CO2 uptake at 273 K. Additionally, it displays significant selectivity for CO2 adsorption over N2 and H2 and can catalyse size-selective Knoevenagel condensation reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Permanent gas analysis using gas chromatography with vacuum ultraviolet detection.

    Science.gov (United States)

    Bai, Ling; Smuts, Jonathan; Walsh, Phillip; Fan, Hui; Hildenbrand, Zacariah; Wong, Derek; Wetz, David; Schug, Kevin A

    2015-04-03

    The analysis of complex mixtures of permanent gases consisting of low molecular weight hydrocarbons, inert gases, and toxic species plays an increasingly important role in today's economy. A new gas chromatography detector based on vacuum ultraviolet (VUV) spectroscopy (GC-VUV), which simultaneously collects full scan (115-240 nm) VUV and UV absorption of eluting analytes, was applied to analyze mixtures of permanent gases. Sample mixtures ranged from off-gassing of decomposing Li-ion and Li-metal batteries to natural gas samples and water samples taken from private wells in close proximity to unconventional natural gas extraction. Gas chromatography separations were performed with a porous layer open tubular column. Components such as C1-C5 linear and branched hydrocarbons, water, oxygen, and nitrogen were separated and detected in natural gas and the headspace of natural gas-contaminated water samples. Of interest for the transport of lithium batteries were the detection of flammable and toxic gases, such as methane, ethylene, chloromethane, dimethyl ether, 1,3-butadiene, CS2, and methylproprionate, among others. Featured is the capability for deconvolution of co-eluting signals from different analytes.

  17. Carrier dynamics of optical emission from two-dimensional electron gas in undoped AlGaN/GaN single heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Kwack, H.S.; Cho, Y.H. [Department of Physics and Institute for Basic Science Research, Chungbuk National University, Cheongju 361-763 (Korea); Kim, G.H. [School of Information and Communication Engineering, Sungkyunkwan University, Suwon 440-746 (Korea); Park, M.R.; Youn, D.H.; Bae, S.B.; Lee, K.S. [Basic Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon 305-350 (Korea); Lee, J.H.; Lee, J.H. [Department of Electric and Electronic Engineering, Kyungpook National University, Taegu 702-701 (Korea)

    2006-06-15

    The structural and optical properties of undoped AlGaN/GaN single heterojunctions (HJs) were studied by means of high-resolution x-ray diffraction, photoluminescence (PL), cathodoluminescence (CL), and time-resolved PL spectroscopy. An additional two-dimensional electron gas (2DEG)-related PL and CL emission appeared at about 40 meV below the GaN band-edge emission energy and persisted up to about 100 K, while this peak disappeared when the top AlGaN layer was removed by reactive ion etching. Depth-resolved CL spectra reveal the presence of a 2DEG at the heterointerface. The additional PL and CL emission below the GaN band-edge emission is attributed to the recombination between photogenerated holes and electrons confined at 2DEG states in the triangular-shaped interface potential. For the 2DEG emission, we observed an about 50-ps delayed rise time than the GaN and AlGaN emissions by using time-resolved PL, indicating effective carrier transfer from the GaN flatband and AlGaN regions to the heterointerface. From the results, we explained the optical properties and carrier recombination dynamics of 2DEG, GaN, and AlGaN emissions in undoped AlGaN/GaN single HJs. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Carrier dynamics of optical emission from two-dimensional electron gas in undoped AlGaN/GaN single heterojunctions

    Science.gov (United States)

    Kwack, H. S.; Cho, Y. H.; Kim, G. H.; Park, M. R.; Youn, D. H.; Bae, S. B.; Lee, K.-S.; Lee, J. H.; Lee, J. H.

    2006-06-01

    The strucutral and optical properties of undoped AlGaN/GaN single heterojunctions (HJs) were studied by means of high-resolution x-ray diffraction, photoluminescence (PL), cathodoluminescence (CL), and time-resolved PL spectroscopy. An additional two-dimensional electron gas (2DEG)-related PL and CL emission appeared at about 40 meV below the GaN band-edge emission energy and persisted up to about 100 K, while this peak disappeared when the top AlGaN layer was removed by reactive ion etching. Depth-resolved CL spectra reveal the presence of a 2DEG at the heterointerface. The additional PL and CL emission below the GaN band-edge emission is attributed to the recombination between photogenerated holes and electrons confined at 2DEG states in the triangular-shaped interface potential. For the 2DEG emission, we observed an about 50-ps delayed rise time than the GaN and AlGaN emissions by using time-resolved PL, indicating effective carrier transfer from the GaN flatband and AlGaN regions to the heterointerface. From the results, we explained the optical properties and carrier recombination dynamics of 2DEG, GaN, and AlGaN emissions in undoped AlGaN/GaN single HJs.

  19. Phenomenon of dual- and single-retention behaviors of solutes and its validation by computational simulation in linear programmed temperature gas chromatography.

    Science.gov (United States)

    Wu, Liejun; Duan, Xiaojuan; Liu, Chuanyu; Zhang, Guangxiang; Li, Qing X

    2016-07-01

    The current theory of programmed temperature gas chromatography considers that solutes are focused by the stationary phase at the column head completely and does not explicitly recognize the different effects of initial temperature (To ) and heating rate (rT ) on the retention time or temperature of a homologue series. In the present study, n-alkanes, 1-alkenes, 1-alkyl alcohols, alkyl benzenes, and fatty acid methyl esters standards were used as model chemicals and were separated on two nonpolar columns, one moderately polar column and one polar column. Effects of To and rT on the retention of nonstationary phase focusing solutes can be explicitly described with isothermal and cubic equation models, respectively. When the solutes were in the stationary phase focusing status, the single-retention behavior of solutes was observed. It is simple, dependent upon rT only and can be well described by the cubic equation model that was visualized through four sequential slope analyses. These observed dual- and single-retention behaviors of solutes were validated by various experimental data, physical properties, and computational simulation.

  20. Inherently safe passive gas monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    Cordaro, Joseph V.; Bellamy, John Stephen; Shuler, James M.; Shull, Davis J.; Leduc, Daniel R.

    2016-09-06

    Generally, the present disclosure is directed to gas monitoring systems that use inductive power transfer to safely power an electrically passive device included within a nuclear material storage container. In particular, the electrically passive device can include an inductive power receiver for receiving inductive power transfer through a wall of the nuclear material storage container. The power received by the inductive power receiver can be used to power one or more sensors included in the device. Thus, the device is not required to include active power generation components such as, for example, a battery, that increase the risk of a spark igniting flammable gases within the container.

  1. Modeling of Single Lignite Particle Drying Process in Flue Gas%单颗粒褐煤烟气干燥过程模型研究

    Institute of Scientific and Technical Information of China (English)

    郝正虎; 吴玉新; 吕俊复; 张守玉; 王秀军; 彭定茂

    2012-01-01

    摘要:褐煤干燥对提高褐煤品质具有重要意义。为了深入研究高温烟气干燥褐煤的物理过程,在一维球坐标系下对单个球形褐煤颗粒的干燥脱水过程建立了数值模型。模型中以褐煤颗粒内的蒸发界面为基础,将褐煤颗粒分为干区和湿区,对湿区求解传热方程,对干区求解烟气传热和传质方程,模拟褐煤干燥中的水分蒸发过程。模型采用Crank-Nicolson隐式差分方法进行离散化,模拟得到单个褐煤颗粒动态蒸发的过程。利用该模型分析不同粒径褐煤干燥过程中的烟气温度、颗粒含水量、颗粒内部温度分布等变化规律。发现颗粒最高温度不超过烟气和颗粒的最终平衡温度。褐煤颗粒粒径和初始烟气温度对褐煤的干燥过程有重要影响,较高的初始烟气温度条件下所需的干燥时间短,干燥时间近似与褐煤颗粒粒径的平方成正比。%Lignite drying is very useful for improving lignite quality. In order to deeply understand lignite drying process in high temperature flue gas, a onedimensional spherical numerical model of a single lignite particle drying process in flue gas was proposed. In this model, lignite particle was divided into dry region and wet region by an evaporation interface. In the wet region, only heat transfer was considered. In the dry region, both heat transfer and mass transfer were involved to describe water evaporation. Crank-Nicolson scheme was adopted to describe the transport equations so that dynamic evaporation process can be correctly solved in a large time step. With the proposed model, gas temperature, moisture content and temperature distribution within the particle varying with the resident time were simulated during drying process. It is found that the maximum particle temperature during drying process is lower than the particleflue gas balance temperature. Particle diameter as well as initial flue gas temperature has an

  2. 无约束气云弱点火爆炸压力实验研究%EXPERIMENTAL STUDY ON EXPLOSION PRESSURES OF UNRESTRICTED GAS CLOUD EXPLOSIONS

    Institute of Scientific and Technical Information of China (English)

    毕明树; 王淑兰; 丁信伟; 罗正鸿

    2001-01-01

    The strength of flammable gas cloud explosion has been experimentally researched by means of acetylene-air clouds which were ignited by electric sparks.The ignition device which provides ignition energy of about 100mJ was made according to international standard ISO 6184 and American Standard NFPA68. The explosion pressure was picked up by pressure transducer with a dynamic responding time of 0.001 s and recorded by computer. By regressing the experimental data,the relationship of gas cloud explosion pressure to the initial radius of gas cloud and the distance to the center of gas cloud can be obtained. That is p=Ar20/r where A is a constant depending on flammable gas cloud.The damage of unrestricted gas cloud to building structure is discussed based on the strength of houses.

  3. CFD Study of Gas Dispersion and Jet Fires in Complex Geometries

    DEFF Research Database (Denmark)

    Osenbroch, Jørgen

    been performed. The results have been compared to large scale experimental findings (Savvides et al. 1999, BG Technology & Shell Global Solutions April 1999). The pre-release ventilation rates are in good quantitative agreement with experiments and well within the criteria for acceptable performance......An implementation and validation of a gas dispersion model and a radiation model in the Computational Fluid Dynamics (CFD) code EXSIM (Sæter 1998, Hjertager et al. 1992) have been performed. The extended code is named FLEXSIM (Fire Leak Explosion Simulator). The computational simulations have been....... The predicted flammable gas volumes show an acceptable quantitative agreement with the majority of the measurements within a factor of two. The flammable gas volumes inside the module are in general over predicted but show an acceptable overall quantitative statistical performance. Two simulations with decaying...

  4. 可燃制冷剂标准修订进展%Progress on the Revision of Safety Standards for Flammable Refrigerants

    Institute of Scientific and Technical Information of China (English)

    吴克安; 郭智恺; 郑冬芳; 谢品赞; 张建君

    2014-01-01

    This paper focused on the revision of safety standards related to the refrigerants and systems’ flammability all over the world. The attitude towards the strongly flammable refrigerant applications such as hydrocarbons was discussed. Result showed that most of the states’ attitudes towards the weaker flammable refrigerants were relaxed, but there were still disagreements for the strongly flammable hydrocarbons.%阐述了全球各主要地区制冷剂及系统关于可燃性的安全标准的修订情况,并介绍了各国对于HCs类易可燃性制冷剂的应用态度。各国对弱可燃制冷剂的态度有所松动,但对于HCs类易燃制冷剂的应用仍有较大分歧。

  5. 19F single-quantum and 19F-33S heteronuclear multiple-quantum coherence NMR of SF6 in thermotropic nematogens and in the gas phase.

    Science.gov (United States)

    Tervonen, Henri; Saunavaara, Jani; Ingman, L Petri; Jokisaari, Jukka

    2006-08-24

    (19)F single-quantum (SQC) and (19)F-(33)S heteronuclear multiple-quantum coherence (HMQC) NMR spectroscopy of sulfur hexafluoride (SF(6)) dissolved in thermotropic liquid crystals (TLCs) were used to investigate the properties of TLCs. On one hand, environmental effects on the NMR parameters of SF(6), (19)F nuclear shielding, (19)F-(33)S spin-spin coupling, secondary isotope effects of sulfur on (19)F shielding, and the self-diffusion coefficient in the direction of the external magnetic field were studied as well. The temperature dependence of the (19)F shielding of SF(6) in TLCs was modeled with a function that takes into account the properties of both TLC and SF(6). It appears that the TLC environment deforms the electronic system of SF(6) so that the (19)F shielding tensor becomes slightly anisotropic, with the anisotropy being from -0.5 to -1.4 ppm, depending upon the TLC solvent. On the contrary, no sign of residual dipolar coupling between (19)F and (33)S was found, meaning that the so-called deformational effects, which arise from the interaction between vibrational and reorientational motions of the molecule, on the geometry of the molecule are insignificant. Diffusion activation energies, E(a), were determined from the temperature dependence of the self-diffusion coefficients. In each TLC, E(a) increases when moving from an isotropic phase to a nematic phase. The spin-spin coupling constant, J((19)F,(33)S), increases by ca. 10 Hz when moving from the gas phase to TLC solutions. The secondary isotope shifts of (19)F shielding are practically independent of TLC solvent and temperature. For the first time, (19)F-(33)S heteronuclear multiple-quantum NMR spectra were recorded for SF(6) in the gas phase and in a liquid-crystalline solution.

  6. Predicting arene rate coefficients with respect to hydroxyl and other free radicals in the gas-phase: a simple and effective method using a single topological descriptor

    Directory of Open Access Journals (Sweden)

    M. R. McGillen

    2007-02-01

    Full Text Available The reactivity of aromatic compounds is of great relevance to pure and applied chemical disciplines, yet existing methods for estimating gas-phase rate coefficients for their reactions with free radicals lack accuracy and universality. Here a novel approach is taken, whereby strong relationships between rate coefficients of aromatic hydrocarbons and a Randić-type topological index are investigated, optimized and developed into a method which requires no specialist software or computing power.

    Measured gas-phase rate coefficients for the reaction of aromatic hydrocarbons with OH radicals were correlated with a calculated Randić-type index, and optimized by including a term for side chain length. Although this method is exclusively for use with hydrocarbons, it is more diverse than any single existing methodology since it incorporates alkenylbenzenes into correlations, and can be extended towards other radical species such as O(3P (and tentatively NO3, H and Cl. A comparison (with species common to both techniques is made between the topological approach advocated here and a popular approach based on electrophilic subsituent constants, where it compares favourably.

    A modelling study was carried out to assess the impact of using estimated rate coefficients as opposed to measured data in an atmospheric model. The difference in model output was negligible for a range of NOx concentrations, which implies that this method has utility in complex chemical models.

    Strong relationships (e.g.~for OH, R2 = 0.96 between seemingly diverse compounds including benzene, multisubstituted benzenes with saturated, unsaturated, aliphatic and cyclic substitutions and the nonbenzenoid aromatic, azulene suggests that the Randić-type index presented here represents a new and effective way of describing aromatic reactivity, based on a quantitative structure-activity relationship (QSAR.

  7. Predicting arene rate coefficients with respect to hydroxyl and other free radicals in the gas-phase: a simple and effective method using a single topological descriptor

    Directory of Open Access Journals (Sweden)

    M. R. McGillen

    2007-07-01

    Full Text Available The reactivity of aromatic compounds is of great relevance to pure and applied chemical disciplines, yet existing methods for estimating gas-phase rate coefficients for their reactions with free radicals lack accuracy and universality. Here a novel approach is taken, whereby strong relationships between rate coefficients of aromatic hydrocarbons and a Randić-type topological index are investigated, optimized and developed into a method which requires no specialist software or computing power.

    Measured gas-phase rate coefficients for the reaction of aromatic hydrocarbons with OH radicals were correlated with a calculated Randić-type index, and optimized by including a term for side chain length. Although this method is exclusively for use with hydrocarbons, it is more diverse than any single existing methodology since it incorporates alkenylbenzenes into correlations, and can be extended towards other radical species such as O(3P (and tentatively NO3, H and Cl. A comparison (with species common to both techniques is made between the topological approach advocated here and a popular approach based on electrophilic subsituent constants, where it compares favourably.

    A modelling study was carried out to assess the impact of using estimated rate coefficients as opposed to measured data in an atmospheric model. The difference in model output was negligible for a range of NOx concentrations, which implies that this method has utility in complex chemical models.

    Strong relationships (e.g. for OH, R2=0.96 between seemingly diverse compounds including benzene, multisubstituted benzenes with saturated, unsaturated, aliphatic and cyclic substitutions and the nonbenzenoid aromatic, azulene suggests that the Randić-type index presented here represents a new and effective way of describing aromatic reactivity, based on a quantitative structure-activity relationship (QSAR.

  8. Regional long-term production modeling from a single well test, Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

    Science.gov (United States)

    Anderson, B.J.; Kurihara, M.; White, M.D.; Moridis, G.J.; Wilson, S.J.; Pooladi-Darvish, M.; Gaddipati, M.; Masuda, Y.; Collett, T.S.; Hunter, R.B.; Narita, H.; Rose, K.; Boswell, R.

    2011-01-01

    Following the results from the open-hole formation pressure response test in the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well (Mount Elbert well) using Schlumberger's Modular Dynamics Formation Tester (MDT) wireline tool, the International Methane Hydrate Reservoir Simulator Code Comparison project performed long-term reservoir simulations on three different model reservoirs. These descriptions were based on 1) the Mount Elbert gas hydrate accumulation as delineated by an extensive history-matching exercise, 2) an estimation of the hydrate accumulation near the Prudhoe Bay L-pad, and 3) a reservoir that would be down-dip of the Prudhoe Bay L-pad and therefore warmer and deeper. All of these simulations were based, in part, on the results of the MDT results from the Mount Elbert Well. The comparison group's consensus value for the initial permeability of the hydrate-filled reservoir (k = 0.12 mD) and the permeability model based on the MDT history match were used as the basis for subsequent simulations on the three regional scenarios. The simulation results of the five different simulation codes, CMG STARS, HydrateResSim, MH-21 HYDRES, STOMP-HYD, and TOUGH+HYDRATE exhibit good qualitative agreement and the variability of potential methane production rates from gas hydrate reservoirs is illustrated. As expected, the predicted methane production rate increased with increasing in situ reservoir temperature; however, a significant delay in the onset of rapid hydrate dissociation is observed for a cold, homogeneous reservoir and it is found to be repeatable. The inclusion of reservoir heterogeneity in the description of this cold reservoir is shown to eliminate this delayed production. Overall, simulations utilized detailed information collected across the Mount Elbert reservoir either obtained or determined from geophysical well logs, including thickness (37 ft), porosity (35%), hydrate saturation (65%), intrinsic permeability (1000 mD), pore water

  9. Flammability of radiation cross-linked low density polyethylene as an insulating material for wire and cable

    Science.gov (United States)

    Basfar, A. A.

    2002-03-01

    Various formulations of low-density polyethylene blended with ethylene vinyl acetate were prepared to improve the flame retardancy for wire and cable applications. The prepared formulations were cross-linked by γ-rays to 50, 100, 150 and 200 kGy in the presence of trimethylolpropane triacrylate (TMPTA). The effect of thermal aging on mechanical properties of these formulations were investigated. In addition, the influence of various combinations of aluminum trihydroxide and zinc borate as flame retardant fillers on the flammability was explored. Limiting oxygen index (LOI) and average extent of burning were used to characterize the flammability of investigated formulations. An improved flame retardancy of low density polyethylene was achieved by various combinations of flame ratardant fillers and cross-linking by gamma radiation.

  10. Single-walled carbon nanotubes coated fibers for solid-phase microextraction and gas chromatography-mass spectrometric determination of pesticides in Tea samples.

    Science.gov (United States)

    Wu, Fang; Lu, Wanping; Chen, Jinghua; Liu, Wei; Zhang, Lan

    2010-08-15

    Using a single-walled carbon nanotubes (SWCNTs) as stationary phase of solid-phase microextraction (SPME) fibers, a simple, low cost and environmentally friendly method for extraction of 13 pesticides in Tea samples has been developed following gas chromatography-mass spectrometric determination. Potential factors affecting the extraction efficiency were investigated and optimized, including extraction and desorption time, extraction temperature, stirring rate, solution pH and ionic strength. Under optimized conditions, the linearity of the developed method was in the range of 0.125-25 ng/mL with correlation coefficients greater than 0.9928 and the limits of detections (LODs) were 0.027-0.23 ng/mL (S/N=3). Meanwhile, the relative standard deviations (RSDs) for five successive measurements with single fiber, fiber-to-fiber, day-to-day were 2.3-13.0, 8.2-14.6 and 4.1-12.5%, respectively, indicating good reproducibility of the proposed method. The fiber had high extraction efficiency for studied pesticides in comparison with commercial poly(dimethylsiloxane) (PDMS) and polyacrylate (PA) fibers and could be used for more than 70 times without decrease of efficiency. The developed method was successfully applied for the analysis of real samples including green Tea, oolong Tea, white Tea, and flower Tea, and the recoveries of the pesticides spiked in these samples ranged from 75.1 to 118.4%. Chlorfenapyr and lambda-cyhalothrin were found in the Tea samples bought randomly from local market. The results demonstrated that the developed SWCNTs-SPME method was a simple, efficient pretreatment and enrichment procedure for pesticides in complex matrices. Copyright 2010 Elsevier B.V. All rights reserved.

  11. A QSPR model for estimation of lower flammability limit temperature of pure compounds based on molecular structure.

    Science.gov (United States)

    Gharagheizi, Farhad

    2009-09-30

    In this study, a quantitative structure-property relationship was presented to estimate lower flammability limit temperature (LFLT) of pure compounds. This relationship is a multi-linear equation and has six parameters. These chemical structure-based parameters were selected from 1664 molecular-based parameters by genetic algorithm multivariate linear regression (GA-MLR). Since 1171 compounds were used to develop this equation, the model can be used to estimate the LFLT of a wide range of pure compounds.

  12. Experimental flammability limits and associated theoretical flame temperatures as a tool for predicting the temperature dependence of these limits

    OpenAIRE

    Zlochower, Isaac A.

    2012-01-01

    The utility and limitations of adiabatic flame temperature calculations and minimum mixture energies in predicting the temperature dependence of flammability limits are explored. The limiting flame temperatures at constant pressure (1 bar) are calculated using a standard widely-used thermodynamic computer program. The computation is based on the calculated limiting flame temperature value at the reference initial temperature and the experimental limit concentration. The values recently determ...

  13. Flammability of Cellulose-Based Fibers and the Effect of Structure of Phosphorus Compounds on Their Flame Retardancy

    OpenAIRE

    Khalifah A. Salmeia; Milijana Jovic; Audrone Ragaisiene; Zaneta Rukuiziene; Rimvydas Milasius; Daiva Mikucioniene; Sabyasachi Gaan

    2016-01-01

    Cellulose fibers are promoted for use in various textile applications due their sustainable nature. Cellulose-based fibers vary considerably in their mechanical and flammability properties depending on their chemical composition. The chemical composition of a cellulose-based fiber is further dependent on their source (i.e., seed, leaf, cane, fruit, wood, bast, and grass). Being organic in nature, cellulose fibers, and their products thereof, pose considerable fire risk. In this work we have c...

  14. Investigation of the Extinguishing Features for Liquid Fuels and Organic Flammable Liquids Atomized by a Water Flow

    OpenAIRE

    2016-01-01

    The processes of heat and mass transfer were investigated experimentally while moving and evaporating the atomized water flow in high-temperature combustion products of typical liquid fuels and organic flammable liquids: gasoline, kerosene, acetone, crude oil, industrial alcohol. We determined typical periods of liquid extinguishing by an atomized water flow of various dispersability. Data of the discharge of extinguishing medium corresponding to various parameters of atomization and duration...

  15. Considerations on Seismic Design of Installations using Natural Gas Fuel

    Directory of Open Access Journals (Sweden)

    Adriana Tokar

    2016-10-01

    Full Text Available The paper presents issues relating to existing standards underlying seismic design restrictions for non-structural components (NSC related to constructions. Are presented measures that can be implemented to maintain a high level of safety in case of earthquake, natural gas plants, which due to the flammability of fuel, carry some risk of fire or explosion. The purpose of this paper is to highlight the need for seismic design of facilities using natural gas fuel for new buildings but also to review the existing installations in buildings by taking mandatory measures.

  16. Effect of Zirconium Dioxide Nanoparticles as a Mordant on Properties of Wool with Thyme: Dyeing, Flammability and Antibacterial

    Directory of Open Access Journals (Sweden)

    M. Taheri

    2015-03-01

    Full Text Available In this research, the zirconium dioxide nanoparticle was synthesized and the effect of these particles as a mordant on properties of wool fabric in dying process with a natural dye,also flammability and antibacterial properties were studied. The wool fabrics were treated with different concentrations of zirconium dioxide nanoparticles including 1, 3, 6 and 9% o.w.f. and the dyeing process was carried out on the fabrics in the states before, simultaneously and after mordanting with Thyme. The chemical characteristics and the changes induced by zirconium were investigated by Fourier-transform infrared spectra (FTIR.The influence of the amount of nano-ZrO2 and the type of mordanting treatment on dye absorbency were studied by reflectance spectrophotometer (RS. Flammability of samples was investigated by horizontal flammability test (HFT.The antibacterial properties were determined by reduction growth of a Gram-negative bacterium E. coli and a Gram-positive bacterium Staphylococcus aureus. The surfaces of untreated and treated fabrics were evaluated by scanning electron microscopy to observe the morphological changes.

  17. Nanoengineering Ni(x)Fe(1-x) catalysts for gas-phase, selective synthesis of semiconducting single-walled carbon nanotubes.

    Science.gov (United States)

    Chiang, Wei-Hung; Sakr, Mohammed; Gao, Xuan P A; Sankaran, R Mohan

    2009-12-22

    The inhomogeneity of as-grown single-walled carbon nanotubes (SWCNTs), in terms of chiral structure, is a major obstacle to integration of these novel materials in advanced electronics. While separation methods have circumvented this problem, current synthesis approaches must be refined for large-scale production of SWCNTs with uniform properties. In addition, it is highly desirable to alter the initial chirality distribution which constrains fundamental study and applications. Here, we demonstrate that semiconducting SWCNTs are selectively produced in the gas phase by engineering catalysts at the nanoscale with precise size and composition. The semiconducting content in as-grown mixtures of SWCNTs is assessed by UV-visible-NIR absorbance and micro-Raman spectroscopy and reaches a maximum purity of 90% for samples catalyzed by Ni(0.27)Fe(0.73) nanoparticles (2.0 nm mean diameter). Electrical studies are performed on thin film transistors (TFTs) fabricated from as-grown SWCNTs and reveal high on/off current ratios of 10(3).

  18. Ultrasonic nebulization extraction coupled with headspace single drop microextraction and gas chromatography-mass spectrometry for analysis of the essential oil in Cuminum cyminum L.

    Science.gov (United States)

    Wang, Lu; Wang, Ziming; Zhang, Huihui; Li, Xueyuan; Zhang, Hanqi

    2009-08-04

    A novel method for analysis of essential oil in Cuminum cyminum L. using simultaneous ultrasonic nebulization extraction and headspace single drop microextraction (UNE-HS-SDME) followed by gas chromatography-mass spectrometry was developed. Experimental parameters, including the kind of suspended solvent, microdrop volume, sample amount, extraction time, enrichment time and salt concentration were examined and optimized. Compared with hydrodistillation (HD), UNE-HS-SDME provides the advantages of a small amount of sample (50 mg), time-saving (20 min), simplicity, cheapness and low toxicity. In addition, UNE-HS-SDME also provided higher enrichment efficiency and sensitivity compared with stirring extraction (SE)-HS-SDME, ultrasonic assistant extraction (UAE) and UNE. Some constituents in the essential oil, were identified and the detection limits for beta-pinene, p-cymene and gamma-terpinene range from 6.67 pLL(-1) to 14.8 pLL(-1). The results indicated that the UNE-HS-SDME is simple and highly efficient extraction and enrichment technique.

  19. Rapid analysis of Fructus forsythiae essential oil by ionic liquids-assisted microwave distillation coupled with headspace single-drop microextraction followed by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Jiao, Jiao; Ma, Dan-Hui; Gai, Qing-Yan; Wang, Wei; Luo, Meng; Fu, Yu-Jie; Ma, Wei

    2013-12-04

    A rapid, green and effective miniaturized sample preparation and analytical technique, i.e. ionic liquids-assisted microwave distillation coupled with headspace single-drop microextraction (ILAMD-HS-SDME) followed by gas chromatography-mass spectrometry (GC-MS) was developed for the analysis of essential oil (EO) in Fructus forsythiae. In this work, ionic liquids (ILs) were not only used as the absorption medium of microwave irradiation but also as the destruction agent of plant cell walls. 1-Ethyl-3-methylimidazolium acetate ([C2mim]OAc) was chosen as the optimal ILs. Moreover, n-heptadecane (2.0 μL) was selected as the appropriate suspended solvent for the extraction and concentration of EO. Extraction conditions of the proposed method were optimized using the relative peak area of EO constituents as the index, and the optimal operational parameters were obtained as follows: irradiation power (300 W), sample mass (0.7 g), mass ratio of ILs to sample (2.4), temperature (78°C) and time (3.4 min). In comparison to previous reports, the proposed method was faster and required smaller sample amount but could equally monitor all EO constituents with no significant differences.

  20. Morphology of Diamond Layers Grown on Different Facets of Single Crystal Diamond Substrates by a Microwave Plasma CVD in CH4-H2-N2 Gas Mixtures

    Directory of Open Access Journals (Sweden)

    Evgeny E. Ashkinazi

    2017-06-01

    Full Text Available Epitaxial growth of diamond films on different facets of synthetic IIa-type single crystal (SC high-pressure high temperature (HPHT diamond substrate by a microwave plasma CVD in CH4-H2-N2 gas mixture with the high concentration (4% of nitrogen is studied. A beveled SC diamond embraced with low-index {100}, {110}, {111}, {211}, and {311} faces was used as the substrate. Only the {100} face is found to sustain homoepitaxial growth at the present experimental parameters, while nanocrystalline diamond (NCD films are produced on other planes. This observation is important for the choice of appropriate growth parameters, in particular, for the production of bi-layer or multilayer NCD-on-microcrystalline diamond (MCD superhard coatings on tools when the deposition of continuous conformal NCD film on all facet is required. The development of the film morphology with growth time is examined with SEM. The structure of hillocks, with or without polycrystalline aggregates, that appear on {100} face is analyzed, and the stress field (up to 0.4 GPa within the hillocks is evaluated based on high-resolution mapping of photoluminescence spectra of nitrogen-vacancy NV optical centers in the film.

  1. Gas bubble retention and its effect on waste properties: Retention mechanisms, viscosity, and tensile and shear strengths

    Energy Technology Data Exchange (ETDEWEB)

    Gauglitz, P.A.; Rassat, S.D.; Powell, M.R. [and others

    1995-08-01

    Several of the underground nuclear storage tanks at Hanford have been placed on a flammable gas watch list, because the waste is either known or suspected to generate, store, and episodically release flammable gases. Because retention and episodic release of flammable gases from these tanks containing radioactive waste slurries are critical safety concerns, Pacific Northwest Laboratory (PNL) is studying physical mechanisms and waste properties that contribute to the episodic gas release from these storage tanks. This study is being conducted for Westinghouse Hanford Company as part of the PNL Flammable Gas project. Previous investigations have concluded that gas bubbles are retained by the slurry or sludge that has settled at the bottom of the tanks; however, the mechanisms responsible for the retention of these bubbles are not well understood. Understanding the rheological behavior of the waste, particularly of the settled sludge, is critical to characterizing the tendency of the waste to retain gas bubbles and the dynamics of how these bubbles are released from the waste. The presence of gas bubbles is expected to affect the rheology of the sludge, specifically its viscosity and tensile and shear strengths, but essentially no literature data are available to assess the effect of bubbles. The objectives of this study were to conduct experiments and develop theories to understand better how bubbles are retained by slurries and sludges, to measure the effect of gas bubbles on the viscosity of simulated slurries, and to measure the effect of gas bubbles on the tensile and shear strengths of simulated slurries and sludges. In addition to accomplishing these objectives, this study developed correlations, based on the new experimental data, that can be used in large-scale computations of waste tank physical phenomena.

  2. 含氧煤层气液化流程爆炸极限分析%Analysis of flammability limits for liquefaction process of oxygen-bearing coal-bed methane

    Institute of Scientific and Technical Information of China (English)

    李秋英; 王莉; 巨永林

    2011-01-01

    大部分含氧煤层气由于技术限制没有被合理利用,而是直接放空,不仅浪费资源.而且污染大气环境.针对某一典型煤层气气源条件和组分特点,设计了一种新型的液化精馏工艺流程,结合HYSYS软件模拟计算结果以及爆炸极限理论,对该液化精馏工艺流程的爆炸极限进行了分析计算,结果表明煤层气中甲烷浓度在压缩、液化以及节流过程中都高于爆炸上限,操作过程安全性比较高.但在精馏塔顶部甲烷浓度开始低于爆炸上限而导致精馏过程存在安全隐患.首先对原料气进行初步脱氧,然后再通过调整精馏塔塔底采出量来控制塔顶杂质气体中甲烷含量,使得其在整个液化及精馏流程中始终高于爆炸上限.分析结果表明,采取安全措施后整个流程都不存在爆炸危险性,甲烷回收率和产品纯度都较高,而且整个流程能耗也比较低.模拟结果显示,所设计的液化及精馏流程对不同气源具有较好的适用性,分析计算结果为含氧煤层气的杂质分离、操作过程的爆炸极限分析以及安全措施的采取提供了一定的参考.%Most of oxygen-bearing coal-bed methane (CBM) has not been utilized due to the limit in technique for production. The discharged gas leads to not only the waste of resources but also environmental pollution. In this study, a liquefaction process is proposed and designed for the typical CBM. HYSYS software is adopted to simulate the process. The flammability limits are analyzed and calculated based on the flammability limit theory and the simulated results of HYSYS. The results indicate that no flammable hazards exist in the processes of compression, liquefaction and throttling but they may appear at the top of the distillation tower. A method, in which oxygen is first removed from the feed gas with the control of the bottom flowrate (flowrate of the liquid product at column bottom), is adopted to ensure that the methane

  3. The influence of leaf morphology on litter flammability and its utility for interpreting palaeofire.

    Science.gov (United States)

    Belcher, Claire M

    2016-06-05

    Studies of palaeofire rely on quantifying the abundance of fossil charcoals in sediments to estimate changes in fire activity. However, gaining an understanding of the behaviour of palaeofires is also essential if we are to determine the palaeoecological impact of wildfires. Here, I use experimental approaches to explore relationships between litter fire behaviour and leaf traits that are observable in the fossil record. Fire calorimetry was used to assess the flammability of 15 species of conifer litter and indicated that leaf morphology related to litter bulk density and fuel load that determined the duration of burning and the total energy released. These data were applied to a fossil case study that couples estimates of palaeolitter fire behaviour to charcoal-based estimates of fire activity and observations of palaeoecological changes. The case study reveals that significant changes in fire activity and behaviour likely fed back to determine ecosystem composition. This work highlights that we can recognize and measure plant traits in the fossil record that relate to fire behaviour and therefore that further research is warranted towards estimating palaeofire behaviour as it can enhance our ability to interpret the palaeoecological impact of palaeofires throughout Earth's long evolutionary history.This article is part of the themed issue 'The interaction of fire and mankind'.

  4. THERMAL DECOMPOSITION AND FLAMMABILITY OF ACRYLONITRILE-BUTADIENE-STYRENE/MULTI-WALLED CARBON NANOTUBES COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Li-fang Tong; Hai-yun Ma; Zheng-ping Fang

    2008-01-01

    Thermal and flammability properties of acrylonitrile-butadiene-styrene copolymer (ABS) with the addition of multi-walled carbon nanotubes (MWNTs) were studied. ABS/MWNTs composites were prepared via melt blending with the MWNTs content varied from 0.2% to 4.0% by mass. Thermogravimetry results showed that the addition of MWNTs accelerated the degradation of ABS during the whole process under air atmosphere, and both onset and maximum degradation temperature were lower than those of pure ABS. The destabilization effect of MWNTs on the thermal stability of the composites became unobvious under nitrogen, and the addition of MWNTs could improve the maximum degradation temperature. The heat release rate and time of ignition (tign) for the composites reduced greatly with the addition of MWNTs especially when the concentration of nanotubes was higher than 1.0%. The accumulation of carbon nanotubes with a network structure was observed and the char layer became thicker with increasing nanotubes concentration. Results from Raman spectra showed a higher degree of graphitization for the residues of ABS/MWNTs composites.

  5. The deforestation story: testing for anthropogenic origins of Africa's flammable grassy biomes.

    Science.gov (United States)

    Bond, William; Zaloumis, Nicholas P

    2016-06-05

    Africa has the most extensive C4 grassy biomes of any continent. They are highly flammable accounting for greater than 70% of the world's burnt area. Much of Africa's savannas and grasslands occur in climates warm enough and wet enough to support closed forests. The combination of open grassy systems and the frequent fires they support have long been interpreted as anthropogenic artefacts caused by humans igniting frequent fires. True grasslands, it was believed, would be restricted to climates too dry or too cold to support closed woody vegetation. The idea that higher-rainfall savannas are anthropogenic and that fires are of human origin has led to initiatives to 'reforest' Africa's open grassy systems paid for by carbon credits under the assumption that the net effect of converting these system to forests would sequester carbon, reduce greenhouse gases and mitigate global warming. This paper reviews evidence for the antiquity of African grassy ecosystems and for the fires that they sustain. Africa's grassy biomes and the fires that maintain them are ancient and there is no support for the idea that humans caused large-scale deforestation. Indicators of old-growth grasslands are described. These can help distinguish secondary grasslands suitable for reforestation from ancient grasslands that should not be afforested.This article is part of the themed issue 'The interaction of fire and mankind'.

  6. Characterization of the explosion risk in processes involving flammable gases, vapors or dusts; Caracterisation du risque d'explosion dans les procedes mettant en oeuvre des gaz, vapeurs ou poussieres inflammables

    Energy Technology Data Exchange (ETDEWEB)

    Chaineaux, J. [Institut National de l' Environnement Industriel et des Risques, 60 - Verneuil en Halatte (INERIS) (France)

    2001-07-01

    The knowledge of the main flammability, explodability and oxidizability characteristics of flammable gases, vapors and dusts is a necessary prerequisite to the definition of prevention and protection means against explosions. After a recall about the combustion reaction, each characteristic is defined and its link with the physics of combustion starting and propagation is indicated. For some characteristics, the different orders of scale is also indicated in the case of flammable gases, vapors and dusts. (J.S.)

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

    Science.gov (United States)

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

    2007-11-01

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

  8. Quantitative recognition of flammable and toxic gases with artificial neural network using metal oxide gas sensors in embedded platform

    Directory of Open Access Journals (Sweden)

    B. Mondal

    2015-06-01

    Full Text Available Artificial Neural Network (ANN based pattern recognition technique is used for ensuring the reliable evaluation of responses from an array of Zinc Oxide (ZnO based sensors comprising of pure ZnO nano-rods and composites of ZnO–SnO2. All the sensors were fabricated in the lab. The paper first reports the development of an artificial neural network based model for successfully recognizing different concentration of hydrogen, methane and carbon mono-oxide. Feed forward back propagation neural network was used for the classification of the gases at critical concentrations. The optimized ANN algorithm is then embedded in the microcontroller based circuit and finally verified under lab conditions.

  9. Human biomonitoring of aluminium after a single, controlled manual metal arc inert gas welding process of an aluminium-containing worksheet in nonwelders.

    Science.gov (United States)

    Bertram, Jens; Brand, Peter; Hartmann, Laura; Schettgen, Thomas; Kossack, Veronika; Lenz, Klaus; Purrio, Ellwyn; Reisgen, Uwe; Kraus, Thomas

    2015-10-01

    Several existing field studies evaluate aluminium welding works but no thoroughly controlled exposure scenario for welding fume has been described yet. This study provides information about the uptake and elimination of aluminium from welding fumes under controlled conditions. In the Aachen Workplace Simulation Laboratory, we are able to generate welding fumes of a defined particle mass concentration. We exposed 12, until then occupationally unexposed participants with aluminium-containing welding fumes of a metal inert gas (MIG) welding process of a total dust mass concentration of 2.5 mg/m(3) for 6 h. Room air filter samples were collected, and the aluminium concentration in air derived. Urine and plasma samples were collected directly before and after the 6-h lasting exposure, as well as after 1 and 7 days. Human biomonitoring methods were used to determine the aluminium content of the samples with high-resolution continuum source atomic absorption spectrometry. Urinary aluminium concentrations showed significant changes after exposure compared to preexposure levels (mean t(1) (0 h) 13.5 µg/L; mean t(2) (6 h) 23.5 µg/L). Plasma results showed the same pattern but pre-post comparison did not reach significance. We were able to detect a significant increase of the internal aluminium burden of a single MIG aluminium welding process in urine, while plasma failed significance. Biphasic elimination kinetic can be observed. The German BAT of 60 µg/g creatinine was not exceeded, and urinary aluminium returned nearly to baseline concentrations after 7 days.

  10. Rapid analysis of Fructus forsythiae essential oil by ionic liquids-assisted microwave distillation coupled with headspace single-drop microextraction followed by gas chromatography–mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Jiao [State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040 (China); Ma, Dan-Hui [College of Life Sciences, Northeast Forestry University, Harbin 150040 (China); Gai, Qing-Yan; Wang, Wei; Luo, Meng [State Engineering Laboratory of Bio-Resource Eco-Utilization, Northeast Forestry University, Harbin 150040 (China); Fu, Yu-Jie, E-mail: yujie_fu2002@yahoo.com [State Engineering Laboratory of Bio-Resource Eco-Utilization, Northeast Forestry University, Harbin 150040 (China); Ma, Wei, E-mail: mawei@hljucm.net [State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040 (China); School of Pharmaceutical, Heilongjiang University of Chinese Medicine, Harbin 150040 (China)

    2013-12-04

    Graphical abstract: -- Highlights: •A new ILAMD-HS-SDME method is developed for the microextraction of essential oil. •ILs used as destruction agent of plant cell walls and microwave absorption medium. •Parameters affecting the extraction efficiency are optimized by Box–Behnken design. •Procedure benefits: similar constituents, shorter duration and smaller sample amount. •ILAMD-HS-SDME followed by GC–MS is a promising technique in analytical fields. -- Abstract: A rapid, green and effective miniaturized sample preparation and analytical technique, i.e. ionic liquids-assisted microwave distillation coupled with headspace single-drop microextraction (ILAMD-HS-SDME) followed by gas chromatography–mass spectrometry (GC–MS) was developed for the analysis of essential oil (EO) in Fructus forsythiae. In this work, ionic liquids (ILs) were not only used as the absorption medium of microwave irradiation but also as the destruction agent of plant cell walls. 1-Ethyl-3-methylimidazolium acetate ([C{sub 2}mim]OAc) was chosen as the optimal ILs. Moreover, n-heptadecane (2.0 μL) was selected as the appropriate suspended solvent for the extraction and concentration of EO. Extraction conditions of the proposed method were optimized using the relative peak area of EO constituents as the index, and the optimal operational parameters were obtained as follows: irradiation power (300 W), sample mass (0.7 g), mass ratio of ILs to sample (2.4), temperature (78 °C) and time (3.4 min). In comparison to previous reports, the proposed method was faster and required smaller sample amount but could equally monitor all EO constituents with no significant differences.

  11. Dynamics of Crust Dissolution and Gas Release in Tank 241-SY-101

    Energy Technology Data Exchange (ETDEWEB)

    Rassat, Scot D.; Stewart, Charles W.; Wells, Beric E.; Kuhn, William L.; Antoniak, Zenen I.; Cuta, Judith M.; Recknagle, Kurtis P.; Terrones, Guillermo; Viswanathan, Vilayanur V.; Sukamto, Johanes H.; Mendoza, Donaldo P.

    2000-01-24

    Due primarily to an increase in floating crust thickness, the waste level in Tank 241-SY-101 has grown appreciably and the flammable gas volume stored in the crust has become a potential hazard. To remediate gas retention in the crust and the potential for buoyant displacement gas releases from the nonconvective layer at the bottom of the tank, SY-101 will be diluted to dissolve a large fraction of the solids that allow the waste to retain gas. The plan is to transfer some waste out and back-dilute with water in several steps. In this work, mechanisms and rates of waste solids dissolution and gas releases are evaluated theoretically and experimentally. Particular emphasis is given to crust dissolution processes and associated gas releases, although dissolution and gas release from the mixed-slurry and nonconvective layers are also considered. The release of hydrogen gas to the tank domespace is modeled for a number of scenarios. Under the tank conditions expected at the time of back-dilution, no plausible continuous or sudden gas release scenarios resulting in flammable hydrogen concentrations were identified.

  12. A single gas chromatograph for accurate atmospheric mixing ratio measurements of CO2, CH4, N2O, SF6 and CO

    NARCIS (Netherlands)

    van der Laan, S.; Neubert, R. E. M.; Meijer, H. A. J.; Simpson, W.R.

    2009-01-01

    We present an adapted gas chromatograph capable of measuring simultaneously and semi-continuously the atmospheric mixing ratios of the greenhouse gases CO2, CH4, N2O and SF6 and the trace gas CO with high precision and long-term stability. The novelty of our design is that all species are measured

  13. A single gas chromatograph for accurate atmospheric mixing ratio measurements of CO2, CH4, N2O, SF6 and CO

    NARCIS (Netherlands)

    van der Laan, S.; Neubert, R. E. M.; Meijer, H. A. J.; Simpson, W.R.

    2009-01-01

    We present an adapted gas chromatograph capable of measuring simultaneously and semi-continuously the atmospheric mixing ratios of the greenhouse gases CO2, CH4, N2O and SF6 and the trace gas CO with high precision and long-term stability. The novelty of our design is that all species are measured w

  14. 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.

  15. From Fireproof Desert to Flammable Grassland: Buffelgrass Invasion in the Sonoran Desert

    Science.gov (United States)

    Betancourt, J. L.

    2007-12-01

    Only a few decades ago, the Sonoran Desert of northwestern Mexico and southern Arizona was considered mostly fireproof, a case of not enough fine fuel to connect the dominant shrubs and cacti. This has changed with invasions by non-native, winter annual and summer-flower perennial grasses that are rapidly transforming fireproof desert into flammable grassland. Of particular concern is buffelgrass, Pennisetum ciliare, a fire-prone and invasive African perennial grass that has already converted millions of hectares across Sonora since the mid-1960s and has made quick headway in southern and central Arizona beginning in the 1980s. Near Tucson and Phoenix, AZ, buffelgrass invasion is proceeding exponentially, with population expansion (and the costs of mitigation) more than doubling every year. As this conversion progresses, there will be increased fire risks, lost tourist revenue, diminished property values, insurmountable setbacks to conservation efforts, and the threat of large ignition fronts in desert valleys routinely spreading into the mountains. Although somewhat belated, an integrated, multi-jurisdictional effort is being organized to reduce ecological and economic impacts. My presentation will summarize the history and context of buffelgrass introduction and invasion, the disconnect in attitudes and policies across state and international boundaries, ongoing management efforts, the role of science and responsibilities of scientists, accelerated spread with changing climate, and impacts to regional ecosystems and economies. This narrative may serve as a template for other semi-arid lands where buffelgrass and similar grasses have become invasive, including Australia, South America, and many islands in the Pacific Ocean (including Hawaii), Indian Ocean, and Caribbean Sea.

  16. Permeability and flammability study of composite sandwich structures for cryogenic applications

    Science.gov (United States)

    Bubacz, Monika

    Fiber reinforced plastics offer advantageous specific strength and stiffness compared to metals and has been identified as candidates for the reusable space transportation systems primary structures including cryogenic tanks. A number of carbon and aramid fiber reinforced plastics have been considered for the liquid hydrogen tanks. Materials selection is based upon mechanical properties and containment performance (long and short term) and upon manufacturing considerations. The liquid hydrogen tank carries shear, torque, end load, and bending moment due to gusts, maneuver, take-off, landing, lift, drag, and fuel sloshing. The tank is pressurized to about 1.5 atmosphere (14.6psi or 0.1 MPa) differential pressure and on ascent maintains the liquid hydrogen at a temperature of 20K. The objective of the research effort into lay the foundation for developing the technology required for reliable prediction of the effects of various design, manufacturing, and service parameters on the susceptibility of composite tanks to develop excessive permeability to cryogenic fuels. Efforts will be expended on developing the materials and structural concepts for the cryogenic tanks that can meet the functional requirements. This will include consideration for double wall composite sandwich structures, with inner wall to meet the cryogenic requirements. The structure will incorporate nanoparticles for properties modifications and developing barriers. The main effort will be extended to tank wall's internal skin design. The main requirements for internal composite stack are: (1) introduction of barrier film (e.g. honeycomb material paper sheet) to reduce the wall permeability to hydrogen, (2) introduction of nanoparticles into laminate resin to prevent micro-cracking or crack propagation. There is a need to characterize and analyze composite sandwich structural damage due to burning and explosion. Better understanding of the flammability and blast resistance of the composite structures

  17. In situ rheology and gas volume in Hanford double-shell waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, C.W.; Alzheimer, J.M.; Brewster, M.E.; Chen, G.; Reid, H.C.; Shepard, C.L.; Terrones, G. [Pacific Northwest National Lab., Richland, WA (United States); Mendoza, R.E. [Westinghouse Hanford Co., Richland, WA (United States)

    1996-09-01

    This report is a detailed characterization of gas retention and release in 6 Hanford DS waste tanks. The results came from the ball rheometer and void fraction instrument in (flammable gas watch list) tanks SY-101, SY-103, AW-101, AN-103, AN-104, and AN-105 are presented. Instrument operation and derivation of data reduction methods are presented. Gas retention and release information is summarized for each tank and includes tank fill history and instrumentation, waste configuration, gas release, void fraction distribution, gas volumes, rheology, and photographs of the waste column from extruded core samples. Potential peak burn pressure is computed as a function of gas release fraction to portray the `hazard signature` of each tank. It is shown that two tanks remain well below the maximum allowable pressure, even if the entire gas content were released and ignited, and that none of the others present a hazard with their present gas release behavior.

  18. Is methane a new therapeutic gas?

    Directory of Open Access Journals (Sweden)

    Liu Wenwu

    2012-09-01

    Full Text Available Abstract Background Methane is an attractive fuel. Biologically, methanogens in the colon can use carbon dioxide and hydrogen to produce methane as a by-product. It was previously considered that methane is not utilized by humans. However, in a recent study, results demonstrated that methane could exert anti-inflammatory effects in a dog small intestinal ischemia-reperfusion model. Point of view Actually, the bioactivity of methane has been investigated in gastrointestinal diseases, but the exact mechanism underlying the anti-inflammatory effects is required to be further elucidated. Methane can cross the membrane and is easy to collect due to its abundance in natural gas. Although methane is flammable, saline rich in methane can be prepared for clinical use. These seem to be good news in application of methane as a therapeutic gas. Conclusion Several problems should be resolved before its wide application in clinical practice.

  19. About the development of single microdischarges in dielectric barrier discharges in CO2 and CO2/N2 gas mixtures. DBD-MDs in CO2 and CO2/N2

    Science.gov (United States)

    Brandenburg, Ronny; Sarani, Abdollah

    2017-08-01

    The conversion of carbon dioxide as one of the main greenhouse gases into carbon monoxide as a chemical feedstock is considered as so-called carbon capture usage technology. Recently it was shown, that the dissociation of carbon dioxide to carbon monoxide in Dielectric Barrier Discharges can be enhanced by the addition of nitrogen gas. Here, the development of microdischarges in CO2 and CO2/N2 gas mixtures is studied. Therefore, a single filament DBD arrangement operated under sinusoidal high-voltage is investigated by means of spectroscopic and electrical diagnostics with high spatial and temporal resolution and sensitivity. The filament development is similar as in air or other nitrogen-oxygen gas mixtures, but the gas composition influences the duration and other parameters. The higher the CO2 content the weaker the filaments and the faster the quenching of excited molecular states. The optimum power dissipation into single discharge is obtained for a CO2 content between 20 and 30 vol.%.

  20. Preparation of Magnesium Hydroxide and Nanofiber Polymer Composites to Reduce the Flammability and Melt Dripping Behaviour of Polymers

    Directory of Open Access Journals (Sweden)

    S. S. Raza

    2014-12-01

    Full Text Available Nanoscale alumina fibers reduce the flammability and melt dripping behaviour of polymers. Magnesium hydroxide breaks the agglomerates by generating shear and iterative forces. Mixing was done with Brabender Plasticoder. The temperature and time of mixing greatly affects the mixing behaviour. At higher temperatures blow holes were observed. By increasing the mixing time agglomerates were broken to a greater extent. Different concentrations of nanofibers, Magnesium hydroxide and surface treatments are used to investigate the properties of polymer. Thermogravimetric analysis (TGA, optical microscopy and flame test was done to see the effect of different parameters on mixing and flame retardancy behaviour.

  1. In situ formation and characterisation of singly ionised atomic europium in rare gas matrices—Luminescence spectroscopy and MP2 calculations

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, Owen; Davis, Barry; McCaffrey, John G., E-mail: john.mccaffrey@nuim.ie [Department of Chemistry, Maynooth University, National University of Ireland—Maynooth, County Kildare (Ireland)

    2015-02-07

    Irradiation of atomic europium isolated in the solid rare gases, with low intensity laser excitation of the y{sup 8}P←a{sup 8}S resonance transition at ca. 465 nm, is found to produce singly charged europium cations (Eu{sup +}) in large amounts in xenon and in smaller amounts in argon. Confirmation of the formation of matrix-isolated Eu{sup +} is obtained from characteristic absorption bands in the UV and in the visible spectral regions. The luminescence produced with excitation of the cation bands is presented in greatest detail for Eu/Xe and assigned. Excitation of the 4f{sup 7}({sup 8}S{sub 7/2})6p{sub 3/2} absorption bands of Eu{sup +} between 390 and 410 nm produces emission which is quite distinct from that resulting from excitation of the 4f{sup 7}({sup 8}S{sub 7/2})6p{sub 1/2} absorption (430 to 450 nm) features. The latter consists of narrow, resolved emission bands with Stokes shifts ten times smaller than the former. The observed spectral differences are discussed in relation to the different spatial symmetries of the p{sub 3/2} and p{sub 1/2} orbitals in these j-j coupled (7/2, 3/2){sub J} and the (7/2, 1/2){sub J} levels. Møller-Plesset calculations are conducted to obtain the molecular parameters of the neutral Eu-RG and cationic Eu{sup +}-RG diatomics (RG = Ar, Kr, Xe). From the short bond lengths and the strong binding energies obtained for the Eu{sup +}-RG species, these values suggest the isolation of the ion in small, possibly interstitial sites especially in xenon. In contrast, but consistent with previous work [O. Byrne and J. G. McCaffrey, J. Chem. Phys. 134, 124501 (2011)], the interaction potentials calculated herein for the Eu-RG diatomics suggest that the neutral Eu atom occupies tetra-vacancy (tv) and hexa-vacancy (hv) sites in the solid rare gas hosts. Possible reasons for the facile production of Eu{sup +} in the solid rare gases are discussed. The mechanism proposed is that atomic europium is also acting as an electron acceptor

  2. Synthesis of chemically-modified single-walled carbon nanotubes by counter-current ammonia gas injection into the induction thermal plasma process

    Science.gov (United States)

    Shahverdi, Ali

    Pristine single-walled carbon nanotubes (SWCNTs) are poorly dispersible and insoluble in many solvents and need to be chemically modified prior to their use in many applications. This work is focused on the investigation of the synthesis of chemically modified SWCNTs material through an in situ approach. The main objectives of the presented research are: 1) to explore the in situ chemical process during the synthesis of SWCNT and 2) to closely examine the effect of a reactive environment on SWCNTs. Effects of the catalyst type and content on the SWCNTs final product, synthesized by induction thermal plasma (ITP), were studied to replace toxic cobalt (Co) in the feedstock. In this regard, three different catalyst mixtures (i.e. Ni-Y2O3, Ni-Co-Y2O3, and Ni-Mo-Y2O3) were used. Experimental results showed that the catalyst type affects the quality of the SWCNT final product. Similar quality SWCNTs can be produced when the same amount of Co was replaced by Ni. Moreover, the results observed in this experimental work were further explained by thermodynamic calculation results. Thermogravimetry (TG) was used throughout the work to characterize the SWCNTs product. TG was firstly standardized by studying the effects of three main instrumental parameters (temperature ramp, TR, initial mass of the sample, IM, and gas flow rate, FR) on the Tonset and full-width half maximum (FWHM) obtained from TG and derivative TG graphs of carbon black, respectively. Therefore, a two-level factorial statistical design was performed. The statistical analysis showed that the effect of TR, IM, and to a lower extent, FR, is significant on FWHM and insignificant on Tonset. A methodology was then developed based upon the SWCNTs synthesis using the ITP system, through an in situ chemistry approach. Ammonia (NH3) was selected and counter-currently injected into the ITP reactor at three different flow rates and by four different nozzle designs. Numerical simulation indicated a better mixing of NH3 in

  3. Efficiency Assessment of Using Flammable Compounds from Water Treatment and Methanol Production Waste for Plasma Synthesis of Iron-Containing Pigments

    Science.gov (United States)

    Shekhovtsova, Anastasia P.; Karengin, Alexander G.

    2016-08-01

    This article describes the possibility of applying the low-temperature plasma for obtaining iron-containing pigments from water purification and flammable methanol production waste. In this paper were calculated combustion parameters of water-saltorganic compositions (WSOC) with different consists. Authors determined the modes of energy- efficient processing of the previously mentioned waste in an air plasma. Having considered the obtained results there were carried out experiments with flammable dispersed water-saltorganic compositions on laboratory plasma stand. All the experimental results are confirmed by calculations.

  4. Safety Strategies in Flammable and Combustible Place%浅议易燃易爆场所消防安全对策

    Institute of Scientific and Technical Information of China (English)

    田颍

    2011-01-01

    According to the present situation of fire in flammable and explosive place, analyzed the fire characteristics and occurrence regularity in flammable and explosive place, discussed the formation reasons, and explored scientific reasonable and operable measures of fire and explosion.%本文根据易燃易爆场所的火灾现状,分析易燃易爆场所的火灾特点,发生规律,探讨其火灾形成原因,探讨科学合理并具有可操作性的防火防爆对策.

  5. Differences in the risk profiles and risk perception of flammable liquid hazards in San Luis Potosi, Mexico

    Directory of Open Access Journals (Sweden)

    Claudia Yazmín Ortega Montoya

    2014-10-01

    Full Text Available The pace of urbanization and industrialization in developing countries is rapidly increasing. Unfortunately, regulatory and private-sector control of hazards has not always kept pace. This work identifies the level of emergency preparedness in chemical industries and evaluates the spatial distribution of hazards using a worst-case release scenario. Consequently, we identified potentially exposed urban communities and evaluated the social perception of a hazard. This research characterizes risk scenarios in a case study of the industrial area in San Luis Potosi, Mexico. Intervention zones of major concern are recognized when deficiencies in emergency preparedness join a poor social perception of hazards in communities that are potentially exposed. The worst-case scenario radii of flammable chemicals range from 425 m to 733 m. Potentially exposed communities have a limited perception of chemical risk and no training in emergency response. Proximity to an industrial area influences communities towards a better recognition of hazards. However, communities far from the industrial area have higher exposure to low preparedness worst-case scenarios for flammable chemicals and have a larger level of vulnerability because of their lack of risk perception.

  6. Flammability of Cellulose-Based Fibers and the Effect of Structure of Phosphorus Compounds on Their Flame Retardancy

    Directory of Open Access Journals (Sweden)

    Khalifah A. Salmeia

    2016-08-01

    Full Text Available Cellulose fibers are promoted for use in various textile applications due their sustainable nature. Cellulose-based fibers vary considerably in their mechanical and flammability properties depending on their chemical composition. The chemical composition of a cellulose-based fiber is further dependent on their source (i.e., seed, leaf, cane, fruit, wood, bast, and grass. Being organic in nature, cellulose fibers, and their products thereof, pose considerable fire risk. In this work we have compared the flammability properties of cellulose fibers obtained from two different sources (i.e., cotton and peat. Compared to cotton cellulose textiles, peat-based cellulose textiles burn longer with a prominent afterglow which can be attributed to the presence of lignin in its structure. A series of phosphoramidates were synthesized and applied on both cellulose textiles. From thermogravimetric and pyrolysis combustion flow analysis of the treated cellulose, we were able to relate the flame retardant efficacy of the synthesized phosphorus compounds to their chemical structure. The phosphoramidates with methyl phosphoester groups exhibited higher condensed phase flame retardant effects on both types of cellulose textiles investigated in this study. In addition, the bis-phosphoramidates exhibited higher flame retardant efficacy compared to the mono-phosphoramidates.

  7. Altered community flammability in Florida's Apalachicola ravines and implications for the persistence of the endangered conifer Torreya taxifolia.

    Directory of Open Access Journals (Sweden)

    John M Mola

    Full Text Available Plant species and communities often reflect historic fire regimes via ecological and evolutionary responses to recurrent fires. Plant communities of the southeastern USA experience a wide array of fire regimes, perhaps nowhere more marked than the juxtaposition of fire-prone uplands and adjacent mesic ravines along Florida's Apalachicola River. The ravines contain many endemic and disjunct species, most notably the endangered endemic conifer Torreya taxifolia. A rapid decline in T. taxifolia over the past 60 years has been associated with widespread replacement by other tree species. To understand the changes accompanying the shift in ravine composition, we compared leaf litter flammability of nine historic and contemporary species. We measured maximum flame height, flame duration, smoldering duration, mass loss, absorptive capacity, and drying rate. Ordination and perMANOVA suggest the nine species segregated into three distinct groups: the fire-impeding T. taxifolia and Taxus floridana; an intermediate group of three deciduous angiosperms; and a mixed cluster of four flammable species. Results suggest T. taxifolia and T. floridana were fire-impeding species in these communities, while contemporary dominants burn similarly to the upslope pyric species. The increasing presence of fire-facilitating species may portend a shifting fire regime that further imperils T. taxifolia and other rare species in the formerly fire-safe ravines.

  8. Ignition Properties of Thermally Thin Plastics: The Effectiveness of Non-Competitive Char Formation in Reducing Flammability

    OpenAIRE

    Nelson, M. I.; Brindley, J.; McIntosh, A. C.

    2002-01-01

    The retardancy effect of char formation upon the flammability of thermally thin products is investigated. The char is formed in a single-step non-competitive scheme and is assumed to be thermally stable. The criterion for ignition is that of a critical mass flux of volatiles from the solid into the gas phase. Both steady-state and transient formulations of the model are considered. In the high activation energy limit the critical heat flux efficiency in the steady-state model is p...

  9. 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.

  10. An experimental Study on Transverse Hydrogen Gas Injection into Mach 1.8 Airflow Channel—The 1st report:single Circular Injector

    Institute of Scientific and Technical Information of China (English)

    T.Nagashima; Y.Kotani; 等

    1997-01-01

    Experimental results from a series of injection tests of pressurized H2,N2 gases into Mach 1.8 airflows between parallel channel walls through a flush-mounted circular sonic opening have been presented.Schlieren pictures revealed complex interaction flow features including the occurrence of bow/separation shock waves due to the injection as well as the barrel shock/Mach disc structure inside the injected gas stream.The injectant penetration measured by the Mach disc height against the injection pressure showed a good agreement with the correlation curve based upon the “effective back pressure” concept.The revesed flow region beneath the separation shock wave,the injectant wake and its associated flow entrainment were also visualized by the oil paint method.Wall static pressure distributions around the injector were measured in detail,which corresponded very well to the above results of flow visualization. Gas samplings were also undertaken by using the pressure taps to confirm the presence of H2 gas in the spearation region ahead of the injector.Traversing of total pressure and H2 gas concentration at the exit of the test channel showed monotonous increase of the loss while its profile was kept very similar with the injection pressure.The area indicating the loss and the presence of H2 gas almost coincided with each other,which remained to be small to indicate very slow gas mixing/diffusion with the main air flow.With the increase of airflow total temperature to 1200K,a bulk flame was first observed at the exit section.Further increase up to 1460 K observed an ignition flame at the injector.However,the reflection of the bow shock wave was found to be a more likely trigger of the bulk flame ignition within the test section.

  11. Brine and Gas Flow Patterns Between Excavated Areas and Disturbed Rock Zone in the 1996 Performance Assessment for the Waste Isolation Pilot Plant for a Single Drilling Intrusion that Penetrates Repository and Castile Brine Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    ECONOMY,KATHLEEN M.; HELTON,JON CRAIG; VAUGHN,PALMER

    1999-10-01

    The Waste Isolation Pilot Plant (WIPP), which is located in southeastern New Mexico, is being developed for the geologic disposal of transuranic (TRU) waste by the U.S. Department of Energy (DOE). Waste disposal will take place in panels excavated in a bedded salt formation approximately 2000 ft (610 m) below the land surface. The BRAGFLO computer program which solves a system of nonlinear partial differential equations for two-phase flow, was used to investigate brine and gas flow patterns in the vicinity of the repository for the 1996 WIPP performance assessment (PA). The present study examines the implications of modeling assumptions used in conjunction with BRAGFLO in the 1996 WIPP PA that affect brine and gas flow patterns involving two waste regions in the repository (i.e., a single waste panel and the remaining nine waste panels), a disturbed rock zone (DRZ) that lies just above and below these two regions, and a borehole that penetrates the single waste panel and a brine pocket below this panel. The two waste regions are separated by a panel closure. The following insights were obtained from this study. First, the impediment to flow between the two waste regions provided by the panel closure model is reduced due to the permeable and areally extensive nature of the DRZ adopted in the 1996 WIPP PA, which results in the DRZ becoming an effective pathway for gas and brine movement around the panel closures and thus between the two waste regions. Brine and gas flow between the two waste regions via the DRZ causes pressures between the two to equilibrate rapidly, with the result that processes in the intruded waste panel are not isolated from the rest of the repository. Second, the connection between intruded and unintruded waste panels provided by the DRZ increases the time required for repository pressures to equilibrate with the overlying and/or underlying units subsequent to a drilling intrusion. Third, the large and areally extensive DRZ void volumes is a

  12. 16 CFR 1500.43a - Method of test for flashpoint of volatile flammable materials.

    Science.gov (United States)

    2010-01-01

    ... (cooling) fluid is solid carbon dioxide (dry ice) and acetone. If the refrigerant charged cooling module is... test flame, are required. These flames may be fueled by piped gas service. A gage ring 4mm (5/32 in...

  13. Experimental Analysis of Performance and Emission Parameters of Neem Oil Ethyl Ester and HHO Gas Addition with Neem Oil Ethyl Ester in a Single Cylinder Four Stroke Compression Ignition Engine

    Directory of Open Access Journals (Sweden)

    M Subramanian

    2014-04-01

    Full Text Available Need for alternate fuel is increasing day by day due various problems associated with the conventional fuels. Present work is focussed on analysing experimentally the performance and emission characteristics of Neem oil biodiesel and addition of HHO gas along with Neem oil biodiesel in a single cylinder compression ignition engine. Biodiesel is extracted by tranesterification of non edible crude Neem oil using ethanol and Naoh as catalyst. The biodiesel is blended with diesel. The blends used are N30 and N40. HHO gas is produced from the process of electrolysis the HHO gas is the combination of hydrogen and oxygen. The produced gas is made to pass through a moisture separator and sent along the intake manifold with the intake air. The performance and emission characteristics are noted down and compared. It was observed that there was a rise in brake thermal efficiency and lesser specific fuel consumption, Reduced Oxygen content in exhaust gases, lesser HC and CO emission and there was a rise in NOX emission when HHO is supplemented with biodiesel Keywords –

  14. 基于单V锥节流装置的湿气气液流量在线测量%Online Measurement of Gas and Liquid Flow Rate in Wet Gas Base on Single V-cone Throttle

    Institute of Scientific and Technical Information of China (English)

    贺登辉; 张锋; 曹洪贵; 杨园园; 白博峰

    2016-01-01

    The two-phase mass flow coefficient is proposed to correct the deviation of the V-Cone meter when it is used to measure the wet gas. The effects of the Lockhart-Martinelli parameter, the gas densiometric Froude number and the gas to liquid density ratio on the two-phase flow coefficient are experimentally investigated. The diameter ratio of the V-Cone meter is 0.55. The experimental fluids are air and tap water. The gas to liquid density ratio, the gas densiometric Froude number and the Lockhart-Martinelli parameter range from 0.002 445 to 0.006 083, from 0.3 to 2.0 and from 0.01 to 0.34, respectively. The results show that the two-phase mass flow coefficient linearly increases with the Lockhart-Martinelli parameter and is affected by the gas densiometric Froude number and the gas to liquid density ratio. Then the quantitative relationship between the two-phase mass flow coefficient and the Lockhart-Martinelli parameter, the gas densiometric Froude number and the gas to liquid density ratio is obtained, based on which the correlation for the wet gas flow measurement is developed. The differential pressure response of the front and back cone of the V-Cone to the wet gas is investigated and the parameters affecting the different responses are also discussed, and finally the wet gas correlation to meter the gas and liquid mass flow rate is concluded. In the present cases, the relative error of the gas mass flow rate predicted by the correlation is within ±5.0% and the average relative error is 2.2%; the relative error of the liquid mass flow rate predicted by the correlation is within ±20.0% and the average relative error is 9.8%. The method proposed in this study possesses some remarkable performances, including simple structure, low cost and high accuracy.%提出采用两相质量流量系数对V锥节流装置湿气测量误差进行修正,试验研究洛克哈特-马蒂内利参数、气体密度弗鲁德数以及气液密度比对 V 锥节流装置两相质

  15. 秦山三期60Co调节棒提棒后控制棒驱动机构气空间氘气可燃性安全评价%Safety Assessment on Flammability of Deuterium in Air Space of CRDM After Withdrawal of 60Co Control Rod for Qinshan Phase Ⅲ

    Institute of Scientific and Technical Information of China (English)

    方立凯; 丁捷; 付亚茹

    2012-01-01

    由于控制棒驱动机构气空间内的氘气不能完成参与气体复合,而60Co调节棒提出重水液面后棒表面温度较高,因此,需分析气空间内氘气的可燃性.本文采用理论计算加试验的方法,分别确定了60Co调节棒提出重水液面后的温度及氘气混合气的可燃浓度和所需的最小点火温度.通过分析表明,在正常运行20个月内,60Co调节棒提棒不会造成氘气混合气的爆燃.%Since the deuterium (D2) in CRDM can't be recombined completely, the surface temperature of the 60Co control rod is high when it is withdrawn, and it is required to evaluate the flammability of D2 mixture gas. In this article, theoretical and test method were used to determine the surface temperature of the 80 Co control rod when it was withdrawn, the minimum flammability volume fraction and ignition temperature, respectively. The results show it is unlikely that the high surface temperature can be the potential for D2 ignition.

  16. HST/COS SPECTRA OF THREE QSOs THAT PROBE THE CIRCUMGALACTIC MEDIUM OF A SINGLE SPIRAL GALAXY: EVIDENCE FOR GAS RECYCLING AND OUTFLOW

    Energy Technology Data Exchange (ETDEWEB)

    Keeney, Brian A.; Stocke, John T.; Danforth, Charles W.; Shull, J. Michael; Green, James C. [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Rosenberg, Jessica L. [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States); Ryan-Weber, Emma V. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Mail H30, P.O. Box 218, Hawthorn, 3122 VIC (Australia); Savage, Blair D., E-mail: brian.keeney@colorado.edu [Department of Astronomy, University of Wisconsin-Madison, 5534 Sterling Hall, 475 North Charter Street, Madison, WI 53706 (United States)

    2013-03-01

    We have used the Cosmic Origins Spectrograph (COS) to obtain far-UV spectra of three closely spaced QSO sight lines that probe the circumgalactic medium (CGM) of an edge-on spiral galaxy, ESO 157-49, at impact parameters of 74 and 93 h {sup -1} {sub 70} kpc near its major axis and 172 h {sup -1} {sub 70} kpc along its minor axis. H I Ly{alpha} absorption is detected at the galaxy redshift in the spectra of all three QSOs, and metal lines of Si III, Si IV, and C IV are detected along the two major-axis sight lines. Photoionization models of these clouds suggest metallicities close to the galaxy metallicity, cloud sizes of {approx}1 kpc, and gas masses of {approx}10{sup 4} M {sub Sun }. Given the high covering factor of these clouds, ESO 157-49 could harbor {approx}2 Multiplication-Sign 10{sup 9} M {sub Sun} of warm CGM gas. We detect no metals in the sight line that probes the galaxy along its minor axis, but gas at the galaxy metallicity would not have detectable metal absorption with ionization conditions similar to the major-axis clouds. The kinematics of the major-axis clouds favor these being portions of a 'galactic fountain' of recycled gas, while two of the three minor-axis clouds are constrained geometrically to be outflowing gas. In addition, one of our QSO sight lines probes a second more distant spiral, ESO 157-50, along its major axis at an impact parameter of 88 h {sup -1} {sub 70} kpc. Strong H I Ly{alpha} and C IV absorption only are detected in the QSO spectrum at the redshift of ESO 157-50.

  17. 49 CFR 176.400 - Stowage of Division 1.5, Class 4 (flammable solids) and Class 5 (oxidizers and organic peroxides...

    Science.gov (United States)

    2010-10-01

    ...) and Class 5 (oxidizers and organic peroxides) materials. 176.400 Section 176.400 Transportation Other... Solids), Class 5 (Oxidizers and Organic Peroxides), and Division 1.5 Materials § 176.400 Stowage of Division 1.5, Class 4 (flammable solids) and Class 5 (oxidizers and organic peroxides) materials. (a)...

  18. Measurement for the Flammability Point of Mg and Mg Alloy%镁及镁合金燃点的测试

    Institute of Scientific and Technical Information of China (English)

    陈萍; 张茂勋

    2001-01-01

    The three experimental sketches were made to measure the flammability point according to the physical and chemical characteristics of Mg and Mg alloy by the conventional methods of measuring the flammable solid mate rial's flammability point. Moreover, the results were analyzed. It was prelimina rily defined the possible temperature region of the Mg and Mg alloy's flammability point exists under certain grain size and temperature raising condition, so do the influence of the grain size and temperature raising condition on the flamm ability point.%根据镁及镁合金的物理、化学特性,借鉴常规可燃固体材料燃点的测试方法,设计了三种试 验方案,并对其结果进行处理分析。初步确定了在一定粒度和升温条件下镁及镁合金燃点可 能存在的温度区间以及粒度和升温条件对其燃点的影响。

  19. Explosion impacts during transport of hazardous cargo: GIS-based characterization of overpressure impacts and delineation of flammable zones for ammonia.

    Science.gov (United States)

    Inanloo, Bahareh; Tansel, Berrin

    2015-06-01

    The aim of this research was to investigate accidental releases of ammonia followed by an en-route incident in an attempt to further predict the consequences of hazardous cargo accidents. The air dispersion model Areal Locations of Hazardous Atmospheres (ALOHA) was employed to track the probable outcomes of a hazardous material release of a tanker truck under different explosion scenarios. The significance of identification of the flammable zones was taken into consideration; in case the flammable vapor causes an explosion. The impacted areas and the severity of the probable destructions were evaluated for an explosion by considering the overpressure waves. ALOHA in conjunction with ArcGIS was used to delineate the flammable and overpressure impact zones for different scenarios. Based on the results, flammable fumes were formed in oval shapes having a chief axis along the wind direction at the time of release. The expansions of the impact areas under the overpressure value which can lead to property damage for 2 and 20 tons releases, under very stable and unstable atmospheric conditions were estimated to be around 1708, 1206; 3742, 3527 feet, respectively, toward the wind direction. A sensitivity analysis was done to assess the significance of wind speed on the impact zones. The insight provided by this study can be utilized by decision makers in transportation of hazardous materials as a guide for possible rerouting, rescheduling, or limiting the quantity of hazardous cargo to reduce the possible impacts after hazardous cargo accidents during transport.

  20. Evaluation of Reformer Produced Synthesis Gas for Emissions Reductions in Natural Gas Reciprocating Engines

    Energy Technology Data Exchange (ETDEWEB)

    Mark V. Scotto; Mark A. Perna

    2010-05-30

    Rolls-Royce Fuel Cell Systems (US) Inc. (RRFCS) has developed a system that produces synthesis gas from air and natural gas. A near-term application being considered for this technology is synthesis gas injection into reciprocating engines for reducing NOx emissions. A proof of concept study using bottled synthesis gas and a two-stroke reciprocating engine showed that injecting small amounts of highflammables content synthesis gas significantly improved combustion stability and enabled leaner engine operation resulting in over 44% reduction in NOx emissions. The actual NOx reduction that could be achieved in the field is expected to be engine specific, and in many cases may be even greater. RRFCS demonstrated that its synthesis gas generator could produce synthesis gas with the flammables content that was successfully used in the engine testing. An economic analysis of the synthesis gas approach estimates that its initial capital cost and yearly operating cost are less than half that of a competing NOx reduction technology, Selective Catalytic Reduction. The next step in developing the technology is an integrated test of the synthesis gas generator with an engine to obtain reliability data for system components and to confirm operating cost. RRFCS is actively pursuing opportunities to perform the integrated test. A successful integrated test would demonstrate the technology as a low-cost option to reduce NOx emissions from approximately 6,000 existing two-stroke, natural gas-fired reciprocating engines used on natural gas pipelines in North America. NOx emissions reduction made possible at a reasonable price by this synthesis gas technology, if implemented on 25% of these engines, would be on the order of 25,000 tons/year.

  1. Gas turbine

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ok Ryong

    2004-01-15

    This book introduces gas turbine cycle explaining general thing of gas turbine, full gas turbine cycle, Ericson cycle and Brayton cycle, practical gas turbine cycle without pressure loss, multiaxial type gas turbine cycle and special gas turbine cycle, application of basic theory on a study on suction-cooling gas turbine cycle with turbo-refrigerating machine using the bleed air, and general performance characteristics of the suction-cooling gas turbine cycle combined with absorption-type refrigerating machine.

  2. Thermal radiation effect on thermal explosion in gas containing fuel droplets

    Science.gov (United States)

    Goldfarb, Igor; Gol'dshtein, Vladimir; Kuzmenko, Grigory; Sazhin, Sergei

    1999-12-01

    The effect of thermal radiation on the dynamics of a thermal explosion of a flammable gas mixture with the addition of volatile fuel droplets is studied. This is based on an original physical model of self-ignition. The thermal radiation energy exchange between the evaporating surface of the fuel droplets and burning gas is described using the P-1 model with Marshak boundary conditions. The original system of equations describing the effects of heating, evaporation and the combustion of fuel droplets is simplified to enable their analysis using asymptotic methods. The mathematical formulation is eventually reduced to a singularly perturbed system of ordinary differential equations. This allows us to apply the advanced geometric asymptotic technique (integral manifold method) for the qualitative analysis of the behaviour of the solution. Possible types of dynamic behaviour of the system are classified and parametric regions of their existence are determined analytically. The main attention is concentrated on the situations where delays might occur before the final ignition. Our study is focused on the impact of thermal radiation on the delay time. The dimensionless parameter responsible for the impact of thermal radiation is singled out and analysed. The dependence of the delay characteristics on the physical parameters of the problem under consideration is analysed. An explicit expression for the minimum time delay of the thermal explosion of fuel droplets in the presence of thermal radiation is derived and applied to the thermal explosion of n-decane and tetralin droplets. It is pointed out that the effects of thermal radiation can be significant, especially at high temperatures, and cannot be ignored in the analysis of this phenomenon.

  3. Gas distribution effects on waste properties: Viscosities of bubbly slurries

    Energy Technology Data Exchange (ETDEWEB)

    Gauglitz, P.A.; Shah, R.R.; Davis, R.L.

    1994-09-01

    The retention and episodic release of flammable gases are critical safety concerns for double-shell tanks that contain waste slurries. The rheological behavior of the waste, particularly of the settled sludge, is critical to characterizing the tendency of the waste to retain gas bubbles. The presence of gas bubbles is expected to affect the rheology of the sludge, but essentially no literature data are available to assess the effect of bubbles. Accordingly, the objectives of this study are to develop models for the effect of gas bubbles on the viscosity of a particulate slurry, develop an experimental method (capillary rheometer), collect data on the viscosity of a bubbly slurry, and develop a theoretical basis for interpreting the experimental data from the capillary rheometer.

  4. Precise control of photoluminescence of silicon-vacancy color centers in homoepitaxial single-crystal diamond: evaluation of efficiency of Si doping from gas phase

    Science.gov (United States)

    Ralchenko, Victor; Sedov, Vadim; Saraykin, Vladimir; Bolshakov, Andrey; Zavedeev, Evgeny; Ashkinazi, Evgeny; Khomich, Andrew

    2016-09-01

    Ability to precisely control the Si-related color center abundance in diamond is important for the use of silicon-vacancy (SiV) defects with bright photoluminescence (PL) in quantum information technologies and optical biomarkers. Here, we evaluated the efficiency of Si incorporation in (100) plane of homoepitaxial diamond layers upon in situ doping by adding silane SiH4 in the course of diamond chemical vapor deposition in microwave plasma using CH4-H2 mixtures. Both the Si concentration in the doped samples, as determined by secondary ion mass spectrometry, and PL intensity of SiV centers at 738 nm wavelength, measured at excitation wavelength of 473 nm, demonstrate a linear increase with silane content in feed gas in the range. The incorporation efficiency f, defined as the ratio of Si concentration in diamond to that in gas, f = [Si/C]dia/[Si/C]gas is found to be (1.1 ± 0.5) × 10-3 for the silane concentrations explored, [SiH4/CH4] < 0.7 %; thus, the Si atoms are accommodated in (100) diamond face easier than nitrogen and phosphorus, but more difficult than boron. This finding allows a tailoring of the Si content and photoluminescence intensity of SiV centers in in situ doped CVD diamond.

  5. Evaluation of Additives to Reduce Solid Propellant Flammability in Ambient Air.

    Science.gov (United States)

    1975-12-01

    WP 4gw«’WUK_u.,HU!«J»B^!PB!*-pi!^p5ggB5,^.IJll.l II Hill JMflH» !,S--*"JU’j*llfgg V. D. Organometallic Compounds E. Enthalpy and Gas Composition...zone near the burning surface of the propellent where the reactive species can be neutralised more effectively. B. Char Formers Several phisphorus... Enthalpy and Gas Composition Measurements of Coolants and Binders* Two experimental techniques were used to measure the enthalpy changes that are

  6. Evaluation of Gas Retention in Waste Simulants: Intermediate-Scale Column and Open-Channel-Depth Tests

    Energy Technology Data Exchange (ETDEWEB)

    Powell, Michael R.; Gauglitz, Phillip A.; Denslow, Kayte M.; Fischer, Christopher M.; Heldebrant, David J.; Prowant, Matthew S.; Sande, Susan; Davis, James M.; Telander, Monty R.

    2014-02-14

    Gas generation in Hanford’s radioactive waste storage tanks can lead to gas accumulation within the layer of settled solids (sludge) at the tank bottom. The gas, which may be hazardous and/or flammable, is formed principally by radiation-driven chemical reactions. Accumulation of these gases within the sludge increases the sludge-layer volume, which decreases the available tank volume for waste storage. Further, accumulation of large amounts of gas in the sludge can potentially result in a relatively rapid release of the accumulated gas if the sludge-layer density is reduced to less than that of the overlying sludge or that of the supernatant liquid. The potential for rapid release of large amounts of hazardous and/or flammable gases is a safety hazard that needs to be managed. Accordingly, a thorough understanding is needed of the circumstances that can lead to problematic gas accumulation in sludge layers. The Deep-Sludge Gas Release Event Project (DSGREP) is tasked with developing an improved understanding of these gas release events.

  7. Effects of Lewis-acid polymer on the electrochemical properties of alkylphosphate-based non-flammable gel electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Lalia, Boor Singh; Yoshimoto, Nobuko; Egashira, Minato; Morita, Masayuki [Department of Applied Chemistry, Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube 755-8611 (Japan)

    2009-10-20

    Non-flammable polymer gel electrolytes (NPGE) consisting of 1.0 mol dm{sup -3} (=M) LiBF{sub 4}/EC + DEC + TEP (55:25:20 volume ratio) + PVdF-HFP (EC: ethylene carbonate, DEC: diethyl carbonate, TEP: triethylphosphate, PVdF-HFP: poly(vinyledenefluoride-co-hexafluoropropylene)) have been developed for rechargeable lithium batteries. The effects of addition of Lewis-acid polymer (LAP) with different mole ratio in NPGE have been studied. The addition of LAP improved physico-chemical properties of NPGE, viz ionic conductivity and lithium ion transport number, as well as mechanical and thermal properties. The ionic conductivity of the gel electrolyte containing LAP reached that of the base solution electrolyte (1.0 M LiBF{sub 4}/EC + DEC + TEP (55:25:20)) along with better mechanical properties. Interfacial resistance at Li-metal electrode/NPGE was also improved by introducing LAP in the gel. (author)

  8. Effects of Lewis-acid polymer on the electrochemical properties of alkylphosphate-based non-flammable gel electrolyte

    Science.gov (United States)

    Lalia, Boor Singh; Yoshimoto, Nobuko; Egashira, Minato; Morita, Masayuki

    Non-flammable polymer gel electrolytes (NPGE) consisting of 1.0 mol dm -3 (=M) LiBF 4/EC + DEC + TEP (55:25:20 volume ratio) + PVdF-HFP (EC: ethylene carbonate, DEC: diethyl carbonate, TEP: triethylphosphate, PVdF-HFP: poly(vinyledenefluoride-co-hexafluoropropylene)) have been developed for rechargeable lithium batteries. The effects of addition of Lewis-acid polymer (LAP) with different mole ratio in NPGE have been studied. The addition of LAP improved physico-chemical properties of NPGE, viz ionic conductivity and lithium ion transport number, as well as mechanical and thermal properties. The ionic conductivity of the gel electrolyte containing LAP reached that of the base solution electrolyte (1.0 M LiBF 4/EC + DEC + TEP (55:25:20)) along with better mechanical properties. Interfacial resistance at Li-metal electrode/NPGE was also improved by introducing LAP in the gel.

  9. Fabrication of polystyrene/agave particle biocomposites using compression molding technique: evaluation of flammability, biodegradability, mechanical and thermal behaviour

    Indian Academy of Sciences (India)

    A S Singha; Raj K Rana

    2013-12-01

    Polystyrene (PS) composites reinforced with ungrafted and acrylonitrile (AN) grafted agave particles (AgP) have been prepared with 10–30% particle content by weight using compression molding technique. The composite specimens thus prepared were subjected to the evaluation of mechanical, chemical, flammability and biodegradability properties. PS composites with 20% particle loading exhibited optimum mechanical properties. AN grafted AgP/PS composites exhibited higher mechanical strength as compared to ungrafted AgP/PS composites. Further AN grafted AgP/PS composites exhibited better thermal properties and biodegradability as compared to PS matrix. Addition of fire retardant fillers such as magnesium hydroxide Mg(OH)2 and zinc borate lowered burning rate of PS composites considerably. Scanning electron microscopy (SEM) of tensile fracture surfaces of AN grafted AgP/PS composites showed better particle/matrix adhesion.

  10. Effect of Particle Size of Additives on the Flammability and Mechanical Properties of Intumescent Flame Retarded Polypropylene Compounds

    Directory of Open Access Journals (Sweden)

    Katalin Bocz

    2015-01-01

    Full Text Available The effect of particle size reduction of the components of a common intumescent flame retardant system, consisting of pentaerythritol (PER and ammonium polyphosphate (APP in a weight ratio of 1 to 2, was investigated on the flammability and mechanical performance of flame retarded polypropylene (PP compounds. Additives of reduced particle size were obtained by ball milling. In the case of PER, the significant reduction of particle size resulted in inferior flame retardant and mechanical performance, while the systems containing milled APP noticeably outperformed the reference intumescent system containing as-received additives. The beneficial effect of the particle size reduction of APP is explained by the better distribution of the particles in the polymer matrix and by the modified degradation mechanism which results in the formation of an effectively protecting carbonaceous foam accompanied with improved mechanical resistance. Nevertheless, 10% higher tensile strength was measured for the flame retarded PP compound when as-received APP was substituted by milled APP.

  11. Design of the liquefied natural gas (LNG) vehicle gas cylinder filling semi-physical simulation training and assessment system

    Science.gov (United States)

    Gao, Jie; Zheng, Jianrong; Zhao, Yinghui

    2017-08-01

    With the rapid development of LNG vehicle in China, the operator's training and assessment of the operating skills cannot operate on material objects, because of Vehicle Gas Cylinder's high pressure, flammable and explosive characteristics. LNG Vehicle Gas Cylinder's filling simulation system with semi-physical simulation technology presents the overall design and procedures of the simulation system, and elaborates the realization of the practical analog machine, data acquisition and control system and the computer software, and introduces the design process of equipment simulation model in detail. According to the designed assessment system of the Vehicle Gas Cylinder, it can obtain the operation on the actual cylinder filling and visual effects for the operator, and automatically record operation, the results of real operation with its software, and achieve the operators' training and assessment of operating skills on mobile special equipment.

  12. Preventing and controlling accidental gas releases

    Science.gov (United States)

    Moskowitz, P. D.; Fthenakis, V. M.; Kalb, P. D.

    1988-07-01

    Toxic, flammable, and explosive gases may be used in photovoltaic cell research laboratories and in commercial manufacturing facilities. Accidental release of these materials can present hazards to life and property. Accidents can arise from a variety of mechanical and human related failures. These can occur from the time materials are received at the loading dock of the facility to the time treated gases are discharged to the atmosphere through a stack. Each type of initiating event may require a different control approach. These may range from the training and certification of plant workers charged with the handling of gas cylinder hookups to installation of emergency pollution control systems. Since engineering options for controlling released materials are limited, emphasis should be placed on administrative and engineering approaches for preventing such accidents. These are likely to be the most effective approaches for protecting life and property.

  13. Baseline intrinsic flammability of Earth’s ecosystems estimated from paleoatmospheric oxygen over the past 350 million years

    Science.gov (United States)

    Belcher, Claire M.; Yearsley, Jonathan M.; Hadden, Rory M.; McElwain, Jennifer C.; Rein, Guillermo

    2010-01-01

    Atmospheric oxygen (O2) is estimated to have varied greatly throughout Earth’s history and has been capable of influencing wildfire activity wherever fuel and ignition sources were present. Fires consume huge quantities of biomass in all ecosystems and play an important role in biogeochemical cycles. This means that understanding the influence of O2 on past fire activity has far-reaching consequences for the evolution of life and Earth’s biodiversity over geological timescales. We have used a strong electrical ignition source to ignite smoldering fires, and we measured their self-sustaining propagation in atmospheres of different oxygen concentrations. These data have been used to build a model that we use to estimate the baseline intrinsic flammability of Earth’s ecosystems according to variations in O2 over the past 350 million years (Ma). Our aim is to highlight times in Earth’s history when fire has been capable of influencing the Earth system. We reveal that fire activity would be greatly suppressed below 18.5% O2, entirely switched off below 16% O2, and rapidly enhanced between 19–22% O2. We show that fire activity and, therefore, its influence on the Earth system would have been high during the Carboniferous (350–300 Ma) and Cretaceous (145–65 Ma) periods; intermediate in the Permian (299–251 Ma), Late Triassic (285–201 Ma), and Jurassic (201–145 Ma) periods; and surprisingly low to lacking in the Early–Middle Triassic period between 250–240 Ma. These baseline variations in Earth’s flammability must be factored into our understanding of past vegetation, biodiversity, evolution, and biogeochemical cycles. PMID:21149686

  14. Cyanuric chloride derivatives for cotton textile treatment--synthesis, analysis, and flammability testing

    Science.gov (United States)

    In a series of experiments, two cyanuric chloride derivatives were synthesized in good yields and analyzed by 1H, 13C, and 31P nuclear magnetic resonance spectroscopy as well as high performance liquid and gas chromatography-mass spectroscopy. Cotton fabric was treated with these compounds and teste...

  15. Selective Plasmonic Gas Sensing: H2, NO2, and CO Spectral Discrimination by a Single Au-CeO2 Nanocomposite Film

    Energy Technology Data Exchange (ETDEWEB)

    Joy, N.; Nandasiri, Manjula I.; Rogers, Phillip H.; Jiang, Weilin; Varga, Tamas; Kuchibhatla, Satyanarayana V N T; Thevuthasan, Suntharampillai; Carpenter, Michael A.

    2012-06-05

    A Au-CeO2 nanocomposite film has been investigated as a potential sensing element for high-temperature plasmonic sensing of H2, CO, and NO2 in an oxygen containing environment. The CeO2 thin film was deposited by molecular beam epitaxy (MBE) and Au was implanted into the as-grown film at an elevated temperature followed by high temperature annealing to form well-defined Au nanoclusters. The Au-CeO2 nanocomposite film was characterized by x-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). For the gas sensing experiments, separate exposures to varying concentrations of H2, CO, and NO2 were performed at a temperature of 500°C in oxygen backgrounds of 5.0, 10, and ~21% O2. Changes in the localized surface plasmon resonance (LSPR) absorption peak were monitored during gas exposures and are believed to be the result of oxidation-reduction processes that fill or create oxygen vacancies in the CeO2. This process affects the LSPR peak position either by charge exchange with the Au nanoparticles or by changes in the dielectric constant surrounding the particles. Multivariate analysis was used to gauge the inherent selectivity of the film between the separate analytes. From principal component analysis (PCA), unique and identifiable responses were seen for each of the analytes. Linear discriminant analysis (LDA) was also used and showed separation between analytes as well as trends in gas concentration. Results indicate that the Au-CeO2 thin film is selective to O2, H2, CO, and NO2 in separate exposures. Combined with the observed stability over long exposure periods, the Au-CeO2 film shows good potential as an optical sensing element for harsh environmental conditions.

  16. The effect of surfactant on headspace single drop microextraction for the determination of some volatile aroma compounds in citronella grass and lemongrass leaves by gas chromatography

    Science.gov (United States)

    A rapid method for the determination of some volatile aromatic compounds (VACs), including citronellal, citronellol, neral, geranial, geraniol, and eugenol in citronella grass and lemongrass leaves, was developed using surfactant as a surface tension modifier while performing headspace single drop m...

  17. A Study of the Curing and Flammability Properties of Bisphenol A Epoxy Diacrylate Resin Utilizing a Novel Flame Retardant Monomer, bis[di-acryloyloxyethyl]-p-tert-butyl-phenyl Phosphate

    Directory of Open Access Journals (Sweden)

    Syang-Peng Rwei

    2017-02-01

    Full Text Available A UV-curable, flame-retardant monomer, DAPP (bis[di-acryloyloxyethyl]-p-tert-butyl-phenyl-phosphate, was synthesized based on BPDCP (4-tert-butylphenyl-dichloro phosphate and HEA (2-hydroxy ethyl acrylate. DAPP was blended with regular bisphenol A epoxy acrylate (BAEA in various ratios to yield various phosphorus contents. The TGA-IR (thermogravimetric analyzer interface with an infrared spectrometer results demonstrate that compounding 30 mol % DAPP with BAEA significantly reduced the amount of released CO gas. In contrast, the peak intensity of CO2 is independent of phosphorus content. The limiting oxygen index (LOI, reaching the saturated value of 26, and the heat release rate (HRR measured using a cone-calorimeter, 156.43 KW/m2, confirm the saturation point when 30 mol % DAPP was compounded into BAEA. A study of the kinetics of pyrolysis reveals that Ea decreases as the phosphorus content increases. Both the TGA-IR and pyrolysis results reveal that the phosphorus compound DAPP is easily decomposed during the initial stage of burning to form an insulating layer, which inhibits further burning of the resin and the consequent release of other flammable gases.

  18. Conversion of actual flue gas CO 2 via cycloaddition to propylene oxide catalyzed by a single-site, recyclable zirconium catalyst

    KAUST Repository

    Kelly, Michael J.

    2017-06-12

    A reusable zirconium-based catalyst for the cycloaddition of CO2 to propylene oxide (PO) was prepared by the surface organometallic chemistry (SOMC) methodology. Accordingly, well-defined amounts of the ZrCl4·(OEt2)2 precursor were grafted on the surface of silica dehydroxylated at 700°C (SiO2-700) and at 200°C (SiO2-200) in order to afford surface coordination compounds with different podality and chemical environment. The identity of the surface complexes was thoroughly investigated by FT-IR, elemental microanalysis and solid state NMR and applied as a recoverable and reusable heterogeneous catalyst for the title reaction using pure CO2 and flue gas samples from a cement factory. The observed catalytic activity for the isolated zirconium complexes is rationalized by means of systematic DFT calculations.

  19. Total Eddy Currents Induced in Screens of a Symmetrical Three-Phase Single-Pole Gas-Insulated Transmission Line (GIL

    Directory of Open Access Journals (Sweden)

    Zygmunt Piatek

    2008-01-01

    Full Text Available In the paper we discuss the question of eddy currents induced in screens of a symmetrical three-phase singlepole gas-insulated transmission line (GIL. First, we determine the eddy currents induced in the tubular screen by the magnetic field of self-current of the phase conductor. Then the magnetic field in the external parallel phase conductor is presented by means of a vector magnetic potential as Fourrier series. In the non-conducting external and internal area of the screen we use Laplace equation for the magnetic field strength taking into account the reverse reaction of eddy currents induced in the screen. In the conducting screen we apply Helmholtz equation for eddy currents density. Using classical boundary conditions we determine the density of the currents. The solutions obtained are used to determine the total eddy currents induced in all the screens of the GIL under consideration.

  20. A single gas chromatograph for accurate atmospheric mixing ratio measurements of CO2, CH4, N2O, SF6 and CO

    Directory of Open Access Journals (Sweden)

    H. A. J. Meijer

    2009-09-01

    Full Text Available We present an adapted gas chromatograph capable of measuring simultaneously and semi-continuously the atmospheric mixing ratios of the greenhouse gases CO2, CH4, N2O and SF6 and the trace gas CO with high precision and long-term stability. The novelty of our design is that all species are measured with only one device, making it a very cost-efficient system. No time lags are introduced between the measured mixing ratios. The system is designed to operate fully autonomously which makes it ideal for measurements at remote and unmanned stations. Only a small amount of sample air is needed, which makes this system also highly suitable for flask air measurements. In principle, only two reference cylinders are needed for daily operation and only one calibration per year against international WMO standards is sufficient to obtain high measurement precision and accuracy. The system described in this paper is in use since May 2006 at our atmospheric measurement site Lutjewad near Groningen, The Netherlands at 6°21´ E, 53°24´N, 1 m a.s.l. Results show the long-term stability of the system. Observed measurement precisions at our remote research station Lutjewad were: ±0.04 ppm for CO2, ±0.8 ppb for CH4, ±0.8 ppb for CO, ±0.3 ppb for N2O, and ±0.1 ppt for SF6. The ambient mixing ratios of all measured species as observed at station Lutjewad for the period of May 2007 to August 2008 are presented as well.

  1. Gas and Gas Pains

    Science.gov (United States)

    ... problems with gas if you: Are lactose or gluten intolerant Eat a diet rich in fruits, vegetables, whole grains and legumes Drink carbonated beverages Have a chronic intestinal condition, such as irritable bowel syndrome or inflammatory bowel disease Neither age nor sex ...

  2. A safety assessment for proposed pump mixing operations to mitigate episodic gas releases in tank 241-SY-101: Hanford Site,Richland, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Lentsch, J.W.

    1996-07-01

    This safety assessment addresses each of the elements required for the proposed action to remove a slurry distributor and to install, operate, and remove a mixing pump in Tank 241-SY-101,which is located within the Hanford Site, Richland, Washington.The proposed action is required as part of an ongoing evaluation of various mitigation concepts developed to eliminate episodic gas releases that result in hydrogen concentrations in the tank dome space that exceed the lower flammability limit.

  3. Safety assessment for proposed pump mixing operations to mitigate episodic gas releases in tank 241-101-SY: Hanford Site, Richland, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Lentsch, J.W., Westinghouse Hanford

    1996-05-16

    This safety assessment addresses each of the elements required for the proposed action to remove a slurry distributor and to install, operate, and remove a mixing pump in Tank 241-SY-101, which is located within the Hanford Site, Richland, Washington. The proposed action is required as part of an ongoing evaluation of various mitigation concepts developed to eliminate episodic gas releases that result in hydrogen concentrations in the tank dome space that exceed the lower flammability limit.

  4. Is there a Difference in Van Der Waals Interactions between Rare Gas Atoms Adsorbed on Metallic and Semiconducting Single-Walled Carbon Nanotubes?

    Energy Technology Data Exchange (ETDEWEB)

    Chen, De-Li [Univ. of Pittsburgh, PA (United States). Dept. of Chemical and Petroleum Engineering; Mandeltort, Lynn [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Chemistry; Saidi, Wissam A. [Univ. of Pittsburgh, PA (United States). Dept. of Chemical and Petroleum Engineering; Yates, John T. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Chemistry; Cole, Milton W. [Pennsylvania State Univ., University Park, PA (United States). Dept of Physics; Johnson, J. Karl [Univ. of Pittsburgh, PA (United States). Dept. of Chemical and Petroleum Engineering; National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2013-03-01

    Differences in polarizabilities of metallic (M) and semiconducting (S) single-walled carbon nanotubes (SWNTs) might give rise to differences in adsorption potentials. We show from experiments and van der Waals-corrected density functional theory (DFT) that binding energies of Xe adsorbed on M- and S-SWNTs are nearly identical. Temperature programmed desorption of Xe on purified M- and S-SWNTs give similar peak temperatures, indicating that desorption kinetics and binding energies are independent of the type of SWNT. Binding energies computed from vdW-corrected DFT are in good agreement with experiments.

  5. Is there a difference in van der Waals interactions between rare gas atoms adsorbed on metallic and semiconducting single-walled carbon nanotubes?

    Science.gov (United States)

    Chen, De-Li; Mandeltort, Lynn; Saidi, Wissam A; Yates, John T; Cole, Milton W; Johnson, J Karl

    2013-03-29

    The differences in the polarizabilities of metallic (M) and semiconducting (S) single-walled carbon nanotubes (SWNTs) might give rise to differences in adsorption potentials. We show from experiments and van der Waals--corrected density functional theory that the binding energies of Xe adsorbed on M- and S-SWNTs are nearly identical. Temperature programed desorption experiments of Xe on purified M- and S-SWNTs give similar peak temperatures, indicating that desorption kinetics and binding energies are independent of the type of SWNT. Binding energies computed from vdW-corrected density functional theory are in good agreement with experiments.

  6. Research Progress and Development Trend of Anti - flammability Leather%阻燃性皮革的研究进展及其发展趋势

    Institute of Scientific and Technical Information of China (English)

    刘兰; 胡杨; 林海; 但年华; 陈达; 但卫华

    2011-01-01

    The concept of leather's flame - resistant properties was discussed. The development of anti - flammability leather in worldwide was reviewed. Furthermore, the available test and characterization methods of flame - resistant properties were briefly introduced. The development trend of anti - flammability leather was put forward.%阐述了皮革阻燃性的概念,介绍了国内外阻燃性皮革的研究现状,列举了目前能够用于皮革阻燃性能检测的一些测试表征及评价方法,提出了未来阻燃性皮革的发展趋势。

  7. Sino-American regulations and standards of flammability for textiles%中美纺织品燃烧性法规和标准体系

    Institute of Scientific and Technical Information of China (English)

    赵婷; 林云周; 傅佳亚; 方芳

    2011-01-01

    China's regulations and standards of flammability for textiles as well as its development are introduced.The scope and technical requirements of these standards are introduced particularly.At the same time, the flammability technical regulation system for textiles of USA are detailed, so as to provide reference and demonstration for research and establishment of our flama ratardant textiles.%介绍了我国纺织品燃烧性能方面的法规、标准及最新进展,并详细阐述各标准的适用范围和技术要求.同时介绍了美国的纺织品燃烧性技术法规体系,为研究和建立我国的阻燃织物法规体系提供参考.

  8. Single photon ionization (SPI) via incoherent VUV-excimer light: robust and compact time-of-flight mass spectrometer for on-line, real-time process gas analysis.

    Science.gov (United States)

    Mühlberger, F; Wieser, J; Ulrich, A; Zimmermann, R

    2002-08-01

    Fast on-line detection of organic compounds from complex mixtures, such as industrial process gas streams, require selective and sensitive analytical methods. One feasible approach for this purpose is the use of mass spectrometry (MS) with a selective and soft (fragment-free) ionization technique, such as chemical ionization (CI) or photo ionization (PI). Single photon ionization (SPI) with vacuum ultraviolet (VUV) light is a particularly sof tionization technique, well-suited for detection of both aromatic and aliphatic species. Problematic, however, is the generation of the VUV light. In general, the vacuum ultraviolet (VUV) light sources for SPI-MS are based either on lasers (e.g., 118-nm radiation generated by frequency-tripling of the third harmonic of a Nd:YAG laser) or on conventional VUV lamps, such as deuterium lamps. Althoughthe laser-based techniques are very sophisticated and expensive, the conventional lamps have serious drawbacks regarding their optical parameters, such as low-output power, low spectral power density, and broad emission bands. In this work, a novel excimer VUV light source, in which an electron beam is used to form rare gas excimer species, is used. The excimer VUV light sourceproduces brilliant and intense VUV light. The novel VUV light source was coupled to a compact and mobile time-of-flight mass spectrometer (TOFMS). A special interface design, including optical (VUV optics) as well as electronic measures (e.g., pulsed ion extraction) was realized. The use of the excimer VUV lamp for SPI will allow the realization of very compact, rugged, and sensitive SPI-TOFMS devices, which preferably will be adapted for process analytical application or monitoring issues (e.g., chemical warfare detection). The excimer VUV-lamp technology delivers VUV light with a good beam quality and high-output power at low costs. Furthermore, it allows changing the emitted wavelength as well as the bandwidth of the excimer VUV lamp in t he 100-200-nm region

  9. Development of gas chromatography-flame ionization detection system with a single column and liquid nitrogen-free for measuring atmospheric C2-C12 hydrocarbons.

    Science.gov (United States)

    Liu, Chengtang; Mu, Yujing; Zhang, Chenglong; Zhang, Zhibo; Zhang, Yuanyuan; Liu, Junfeng; Sheng, Jiujiang; Quan, Jiannong

    2016-01-04

    A liquid nitrogen-free GC-FID system equipped with a single column has been developed for measuring atmospheric C2-C12 hydrocarbons. The system is consisted of a cooling unit, a sampling unit and a separation unit. The cooling unit is used to meet the temperature needs of the sampling unit and the separation unit. The sampling unit includes a dehydration tube and an enrichment tube. No breakthrough of the hydrocarbons was detected when the temperature of the enrichment tube was kept at -90 °C and sampling volume was 400 mL. The separation unit is a small round oven attached on the cooling column. A single capillary column (OV-1, 30 m × 0.32 mm I.D.) was used to separate the hydrocarbons. An optimal program temperature (-60 ∼ 170 °C) of the oven was achieved to efficiently separate C2-C12 hydrocarbons. There were good linear correlations (R(2)=0.993-0.999) between the signals of the hydrocarbons and the enrichment amount of hydrocarbons, and the relative standard deviation (RSD) was less than 5%, and the method detection limits (MDLs) for the hydrocarbons were in the range of 0.02-0.10 ppbv for sampling volume of 400 mL. Field measurements were also conducted and more than 50 hydrocarbons from C2 to C12 were detected in Beijing city.

  10. Efficiency Assessment of Using Flammable Compounds from Water Treatment and Methanol Production Waste for Plasma Synthesis of Iron-Containing Pigments

    OpenAIRE

    Shekhovtsova, Anastasia; Karengin, Aleksander Grigorievich

    2016-01-01

    This article describes the possibility of applying the low-temperature plasma for obtaining iron-containing pigments from water purification and flammable methanol production waste. In this paper were calculated combustion parameters of water-saltorganic compositions (WSOC) with different consists. Authors determined the modes of energy- efficient processing of the previously mentioned waste in an air plasma. Having considered the obtained results there were carried out experiments with flamm...

  11. Determination of Campesterol, Stigmasterol, and beta-Sitosterol in Saw Palmetto Raw Materials and Dietary Supplements by Gas Chromatography: Single-Laboratory Validation

    Science.gov (United States)

    Sorenson, Wendy R.; Sullivan, Darryl

    2008-01-01

    In conjunction with an AOAC Presidential Task Force on Dietary Supplements, a method was validated for measurement of 3 plant sterols (phytosterols) in saw palmetto raw materials, extracts, and dietary supplements. AOAC Official Method 994.10, “Cholesterol in Foods,” was modified for purposes of this validation. Test samples were saponified at high temperature with ethanolic potassium hydroxide solution. The unsaponifiable fraction containing phytosterols (campesterol, stigmasterol, and beta-sitosterol) was extracted with toluene. Phytosterols were derivatized to trimethylsilyl ethers and then quantified by gas Chromatography with a hydrogen flame ionization detector. The presence of the phytosterols was detected at concentrations greater than or equal to 1.00 mg/100 g based on 2–3 g of sample. The standard curve range for this assay was 0.00250 to 0.200 mg/mL. The calibration curves for all phytosterols had correlation coefficients greater than or equal to 0.995. Precision studies produced relative standard deviation values of 1.52 to 7.27% for campesterol, 1.62 to 6.48% for stigmasterol, and 1.39 to 10.5% for beta-sitosterol. Recoveries for samples fortified at 100% of the inherent values averaged 98.5 to 105% for campesterol, 95.0 to 108% for stigmasterol, and 85.0 to 103% for beta-sitosterol. PMID:16512224

  12. Vibrational spectroscopy of the mass-selected tetrahydrofurfuryl alcohol monomers and its dimers in gas phase using IR depletion and VUV single photon ionization

    Science.gov (United States)

    Wang, Pengchao; Hu, Yongjun; Zhan, Huaqi; Chen, Jiaxin; Jin, Shan; Song, Wentao; Li, Yujian

    2017-10-01

    Tetrahydrofurfuryl alcohol (THFA, C5H10O2) is a close chemical analog of the sugar rings present in the phosphate-deoxyribose backbone structure of the nucleic acids. In present report, the infrared (IR) spectra of the size-selected THFA monomer and its dimer have been investigated in a pulsed supersonic jet using infrared-vacuum ultraviolet (VUV) ionization. Herein, the laser light at 118 nm wavelength served as the source of ;soft; ionization in a time-of-flight mass spectrometer. The IR features for the monomers located at 3622 cm- 1 can be assigned to the intramolecular hydrogen bonding stretch vibrations mainly referring to A and C conformers. Compared with the monomer, however, characteristic peaks for the dimer centered at 3415 and 3453 cm- 1, red shifted 207 and 169 cm- 1, respectively, were associated with the intermolecular hydrogen bonding stretch vibrations. Combined with the quantum-chemical calculations, the dimer in the gas phase preferred cyclic AC conformer stabled by forming two strong intermolecular hydrogen bonds, which shown the high hydrogen bond selectivity in the cluster. The conclusions drawn from the role played in the conformational flexibility by the hydroxyl and ether groups may be extended to other biomolecules.

  13. The influence of CO2 in biogas flammability limit and laminar burning velocity in spark ignited premix combustion at various pressures

    Science.gov (United States)

    Anggono, W.; Wardana, I. N. G.; Lawes, M.; Hughes, K. J.; Wahyudi, S.; Hamidi, N.; Hayakawa, A.

    2016-03-01

    Biogas is an alternative energy source that is sustainable and renewable containing more than 50% CH4 and its biggest impurity or inhibitor is CO2. Demands for replacing fossil fuels require an improved fundamental understanding of its combustion processes. Flammability limits and laminar burning velocities are important characteristics in these processes. Thus, this research focused on the effects of CO2 on biogas flammability limits and laminar burning velocities in spark ignited premixed combustion. Biogas was burned in a spark ignited spherical combustion bomb. Spherically expanding laminar premixed flames, freely propagating from spark ignition in initial, were continuously recorded by a high-speed digital camera. The combustion bomb was filled with biogas-air mixtures at various pressures, CO2 levels and equivalence ratios (ϕ) at ambient temperature. The results were also compared to those of the previous study into inhibitorless biogas (methane) at various pressures and equivalence ratios (ϕ). Either the flammable areas become narrower with increased percentages of carbon dioxide or the pressure become lower. In biogas with 50% CO2 content, there was no biogas flame propagation for any equivalence ratio at reduced pressure (0.5 atm). The results show that the laminar burning velocity at the same equivalence ratio declined in respect with the increased level of CO2. The laminar burning velocities were higher at the same equivalence ratio by reducing the initial pressure.

  14. 一种易燃易爆物自动阻断系统的研究%Study on the Automatic Blocking System of Flammable and Explosive Materials

    Institute of Scientific and Technical Information of China (English)

    高影; 孙慧松; 张晓峰; 曹井新

    2015-01-01

    目前,火灾状态下绝大多数的阻断系统是采用耐高温箱体对易燃易爆物进行隔离,但由于箱体的导热特点,导致易燃易爆物在高温的状态下会直接发生爆炸.该课题针对以上问题,设计一套自动阻断系统,将易燃易爆物放置于耐高温箱体中,火灾发生时形成真空隔离带,并利用无线技术发出火灾报警信息.%At present, in the fire condition, the majority of blocking systems are using high temperature resistant boxes to isolate the flammable and explosive materials. But because of the heat conduction characteristics of boxes, it will lead to the explosion of flammable and explosive materials in high temperature. In view of the problem above, this paper designs a set of automatic blocking system. Place flammable and explosive materials in the high temperature boxes and the vacuum isolation belt is formed when the fire occurs. And use wireless technology to produce fire alarm messages.

  15. 浅析可燃性冷媒空调的安全要求%Analysis on New Safety Requirements for Air Conditioner With Flammable Ignition Source

    Institute of Scientific and Technical Information of China (English)

    范建波; 陈信勇; 肖彪; 于丽

    2015-01-01

    The refrigerant of HCFCs will be phase-out and replaced gradually by environmental refrigerant which are flammable and explosible. At the same time, air conditioner are electrical equipment which contains a lot of live parts, it is easy to ignite flammable gases. This paper analyzes the protection of ignition source of the air conditioner with flammable refrigerant according to the standard. It provides the reference for related personnel.%目前空调行业有计划地进行逐步淘汰HCFCs制冷剂,取而代之的是具有可燃可爆特性的环保制冷剂.空调属于用电设备,含有大量的带电部件,容易点燃可燃性气体.本文结合空调安全标准,浅析可燃制冷剂空调点火源的防护要求,供相关人员参考.

  16. Single step determination of PCB 126 and 153 in rat tissues by using solid phase microextraction/gas chromatography-mass spectrometry: Comparison with solid phase extraction and liquid/liquid extraction.

    Science.gov (United States)

    Poli, Diana; Caglieri, Andrea; Goldoni, Matteo; Castoldi, Anna F; Coccini, Teresa; Roda, Elisa; Vitalone, Annabella; Ceccatelli, Sandra; Mutti, Antonio

    2009-03-15

    A simple and reliable solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) method was developed for the single-step determination of PCBs 126 and 153 in rat brain and serum, using liquid/liquid and solid phase extraction (SPE) as reference techniques. The multi-factor categorical experimental design used to study simultaneously the main parameters and their interactions affecting the efficiency of the method, showed that the use of an 85mum PA exposed at 100 degrees C for 40min was the optimum sampling condition for both PCBs. SPME was then validated by studying its linear dynamic (over two orders of magnitude), limits of detection (brain: 2ng/g, serum: 0.2ng/g) and analytical precision that was within 9% for SPME in both brain and serum. Finally, the method was used to determine the brain and blood target dose in mothers and pups after oral exposure of the mothers.

  17. Superdiffusive gas recovery from nanopores

    Science.gov (United States)

    Wu, Haiyi; He, Yadong; Qiao, Rui

    2016-11-01

    Understanding the recovery of gas from reservoirs featuring pervasive nanopores is essential for effective shale gas extraction. Classical theories cannot accurately predict such gas recovery and many experimental observations are not well understood. Here we report molecular simulations of the recovery of gas from single nanopores, explicitly taking into account molecular gas-wall interactions. We show that, in very narrow pores, the strong gas-wall interactions are essential in determining the gas recovery behavior both quantitatively and qualitatively. These interactions cause the total diffusion coefficients of the gas molecules in nanopores to be smaller than those predicted by kinetic theories, hence slowing down the rate of gas recovery. These interactions also lead to significant adsorption of gas molecules on the pore walls. Because of the desorption of these gas molecules during gas recovery, the gas recovery from the nanopore does not exhibit the usual diffusive scaling law (i.e., the accumulative recovery scales as R ˜t1 /2 ) but follows a superdiffusive scaling law R ˜tn (n >0.5 ), which is similar to that observed in some field experiments. For the system studied here, the superdiffusive gas recovery scaling law can be captured well by continuum models in which the gas adsorption and desorption from pore walls are taken into account using the Langmuir model.

  18. Super-Diffusive Gas Recovery from Nanopores

    CERN Document Server

    Wu, Haiyi; Qiao, Rui

    2016-01-01

    Understanding the recovery of gas from reservoirs featuring pervasive nanopores is essential for effective shale gas extraction. Classical theories cannot accurately predict such gas recovery and many experimental observations are not well understood. Here we report molecular simulations of the recovery of gas from single nanopores, explicitly taking into account molecular gas-wall interactions. We show that, in very narrow pores, the strong gas-wall interactions are essential in determining the gas recovery behavior both quantitatively and qualitatively. These interactions cause the total diffusion coefficients of the gas molecules in nanopores to be smaller than those predicted by kinetic theories, hence slowing down the rate of gas recovery. These interactions also lead to significant adsorption of gas molecules on the pore walls. Because of the desorption of these gas molecules during gas recovery, the gas recovery from the nanopore does not exhibit the usual diffusive scaling law (i.e., the accumulative ...

  19. Scaling of heat transfer in gas-gas injector combustor

    Institute of Scientific and Technical Information of China (English)

    Wang Xiao-Wei; Cai Guo-Biao; Gao Yu-Shan

    2011-01-01

    The scaling of heat transfer in gas-gas injector combuetor is investigated theoretically, numerically and experimentally based on the previous study on the scaling of gas-gas combustion flowfield. The similarity condition of the gas-gas injector combustor heat transfer is obtained by conducting a formulation analysis of the boundary layer Navier-Stokes equations and a dimensional analysis of the corresponding heat transfer phenomenon. Then, a practicable engineering scaling criterion of the gas-gas injector combustor heat transfer is put forward. The criterion implies that when the similarity conditions of inner flowfield are satisfied, the size and the pressure of gas-gas combustion chamber can be changed, while the heat transfer can still be qualitatively similar to the distribution trend and quantitatively correlates well with the size and pressure as q ∝ pc0.8dt-0.2. Based on the criterion, single-element injector chambers with different geometric sizes and at different chamber pressures ranging from 1 MPa to 20 MPa are numerically simulated. A single-element injector chamber is designed and hot-fire tested at seven chamber pressures from 0.92 MPa to 6.1 MPa.The inner wall heat flux are obtained and analysed. The numerical and experimental results both verified the scaling criterion in gas-gas injector combustion chambers under different chamber pressures and geometries.

  20. Principle and Performance of Gas Self-inducing Reactors and Applications to Biotechnology.

    Science.gov (United States)

    Ye, Qin; Li, Zhimin; Wu, Hui

    2016-01-01

    Gas-liquid contacting is an important unit operation in chemical and biochemical processes, but the gas utilization efficiency is low in conventional gas-liquid contactors especially for sparingly soluble gases. The gas self-inducing impeller is able to recycle gas in the headspace of a reactor to the liquid without utilization of additional equipment such as a gas compressor, and thus, the gas utilization efficiency is significantly enhanced. Gas induction is caused by the low pressure or deep vortex at a sufficiently high impeller speed, and the speed at which gas induction starts is termed the critical speed. The critical impeller speed, gas-induction flow rate, power consumption, and gas-liquid mass transfer are determined by the impeller design and operation conditions. When the reactor is operated in a dead-end mode, all the introduced gas can be completely used, and this feature is especially favorable to flammable and/or toxic gases. In this article, the principles, designs, characteristics of self-inducing reactors, and applications to biotechnology are described.