WorldWideScience

Sample records for hydrogen risk analysis

  1. Risk analysis of complex hydrogen infrastructures

    DEFF Research Database (Denmark)

    Markert, Frank; Marangon, Alessia; Carcassi, Marco

    2015-01-01

    delivered, stored and distributed, as e.g. biomass based methane, ethanol, gasoline, diesel as well as the traditional crude oil based products. Hydrogen is also in play as intermediate energy storage to secure the power supply based on large shares of fluctuating energy sources and as an intermediate...

  2. CFD Application to Hydrogen Risk Analysis and PAR Qualification

    Directory of Open Access Journals (Sweden)

    Jinbiao Xiong

    2009-01-01

    Full Text Available A three dimensional computation fluid dynamics (CFD code, GASFLOW, is applied to analyze the hydrogen risk for Qinshan-II nuclear power plant (NPP. In this paper, the effect of spray modes on hydrogen risk in the containment during a large break loss of coolant accident (LBLOCA is analyzed by selecting three different spray strategies, that is, without spray, with direct spray and with both direct and recirculation spray. A strong effect of spray modes on hydrogen distribution is observed. However, the efficiency of the passive auto-catalytic recombiners (PAR is not substantially affected by spray modes. The hydrogen risk is significantly increased by the direct spray, while the recirculation spray has minor effect on it. In order to simulate more precisely the processes involved in the PAR operation, a new PAR model is developed using CFD approach. The validation shows that the results obtained by the model agree well with the experimental results.

  3. Risk and sustainability analysis of complex hydrogen infrastructures

    DEFF Research Database (Denmark)

    Markert, Frank; Marangon, A.; Carcassi, M.

    2017-01-01

    -based fuels. Therefore, future hydrogen supply and distribution chains will have to address several objectives. Such a complexity is a challenge for risk assessment and risk management of these chains because of the increasing interactions. Improved methods are needed to assess the supply chain as a whole....... The method of “Functional modelling” is discussed in this paper. It will be shown how it could be a basis for other decision support methods for comprehensive risk and sustainability assessments....

  4. Technical Analysis of Hydrogen Production

    Energy Technology Data Exchange (ETDEWEB)

    Ali T-Raissi

    2005-01-14

    The aim of this work was to assess issues of cost, and performance associated with the production and storage of hydrogen via following three feedstocks: sub-quality natural gas (SQNG), ammonia (NH{sub 3}), and water. Three technology areas were considered: (1) Hydrogen production utilizing SQNG resources, (2) Hydrogen storage in ammonia and amine-borane complexes for fuel cell applications, and (3) Hydrogen from solar thermochemical cycles for splitting water. This report summarizes our findings with the following objectives: Technoeconomic analysis of the feasibility of the technology areas 1-3; Evaluation of the hydrogen production cost by technology areas 1; and Feasibility of ammonia and/or amine-borane complexes (technology areas 2) as a means of hydrogen storage on-board fuel cell powered vehicles. For each technology area, we reviewed the open literature with respect to the following criteria: process efficiency, cost, safety, and ease of implementation and impact of the latest materials innovations, if any. We employed various process analysis platforms including FactSage chemical equilibrium software and Aspen Technologies AspenPlus and HYSYS chemical process simulation programs for determining the performance of the prospective hydrogen production processes.

  5. Extensive analysis of hydrogen costs

    Energy Technology Data Exchange (ETDEWEB)

    Guinea, D.M.; Martin, D.; Garcia-Alegre, M.C.; Guinea, D. [Consejo Superior de Investigaciones Cientificas, Arganda, Madrid (Spain). Inst. de Automatica Industrial; Agila, W.E. [Acciona Infraestructuras, Alcobendas, Madrid (Spain). Dept. I+D+i

    2010-07-01

    Cost is a key issue in the spreading of any technology. In this work, the cost of hydrogen is analyzed and determined, for hydrogen obtained by electrolysis. Different contributing partial costs are taken into account to calculate the hydrogen final cost, such as energy and electrolyzers taxes. Energy cost data is taken from official URLs, while electrolyzer costs are obtained from commercial companies. The analysis is accomplished under different hypothesis, and for different countries: Germany, France, Austria, Switzerland, Spain and the Canadian region of Ontario. Finally, the obtained costs are compared to those of the most used fossil fuels, both in the automotive industry (gasoline and diesel) and in the residential sector (butane, coal, town gas and wood), and the possibilities of hydrogen competing against fuels are discussed. According to this work, in the automotive industry, even neglecting subsidies, hydrogen can compete with fossil fuels. Hydrogen can also compete with gaseous domestic fuels. Electrolyzer prices were found to have the highest influence on hydrogen prices. (orig.)

  6. Task D: Hydrogen safety analysis

    Energy Technology Data Exchange (ETDEWEB)

    Swain, M.R.; Sievert, B.G. [Univ. of Miami, Coral Gables, FL (United States); Swain, M.N. [Analytical Technologies, Inc., Miami, FL (United States)

    1996-10-01

    This report covers two topics. The first is a review of codes, standards, regulations, recommendations, certifications, and pamphlets which address safety of gaseous fuels. The second is an experimental investigation of hydrogen flame impingement. Four areas of concern in the conversion of natural gas safety publications to hydrogen safety publications are delineated. Two suggested design criteria for hydrogen vehicle fuel systems are proposed. It is concluded from the experimental work that light weight, low cost, firewalls to resist hydrogen flame impingement are feasible.

  7. Accident sequences and causes analysis in a hydrogen production process

    Energy Technology Data Exchange (ETDEWEB)

    Jae, Moo Sung; Hwang, Seok Won; Kang, Kyong Min; Ryu, Jung Hyun; Kim, Min Soo; Cho, Nam Chul; Jeon, Ho Jun; Jung, Gun Hyo; Han, Kyu Min; Lee, Seng Woo [Hanyang Univ., Seoul (Korea, Republic of)

    2006-03-15

    Since hydrogen production facility using IS process requires high temperature of nuclear power plant, safety assessment should be performed to guarantee the safety of facility. First of all, accident cases of hydrogen production and utilization has been surveyed. Based on the results, risk factors which can be derived from hydrogen production facility were identified. Besides the correlation between risk factors are schematized using influence diagram. Also initiating events of hydrogen production facility were identified and accident scenario development and quantification were performed. PSA methodology was used for identification of initiating event and master logic diagram was used for selection method of initiating event. Event tree analysis was used for quantification of accident scenario. The sum of all the leakage frequencies is 1.22x10{sup -4} which is similar value (1.0x10{sup -4}) for core damage frequency that International Nuclear Safety Advisory Group of IAEA suggested as a criteria.

  8. The Risk of Hydrogen Explosion an a Submarine Part 3 Production of Hydrogen Mixes

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard

    2017-03-01

    Full Text Available This series of articles presents the problems associated with the conduction of a high-risk project aimed at modernising the hydrogen combustion engines on a submarine. The article describes technical issues connected with obtaining hydrogen-air mixes.

  9. The risk of hydrogen explosion in a submarine p.I Catalytic combustion of hydrogen

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard

    2016-09-01

    Full Text Available The series of articles discuss issues related to conducting high risk projects on the example of modernisation of hydrogen incinerators on a submarine. The article depicts a technical problem situation connected with catalytic hydrogen combustion on a submarine.

  10. Hydrogen emissions and their effects on the arctic ozone losses. Risk analysis of a global hydrogen economy; Wasserstoff-Emissionen und ihre Auswirkungen auf den arktischen Ozonverlust. Risikoanalyse einer globalen Wasserstoffwirtschaft

    Energy Technology Data Exchange (ETDEWEB)

    Feck, Thomas

    2009-07-01

    Hydrogen (H{sub 2}) could be used as one of the major components in our future energy supply in an effort to avoid greenhouse gas emissions. ''Green'' hydrogen in particular, which is produced from renewable energy sources, should significantly reduce emissions that damage the climate. Despite this basically environmentally-friendly property, however, the complex chain of interactions of hydrogen with other compounds means that the implications for the atmosphere must be analysed in detail. For example, H{sub 2} emissions, which could increase the tropospheric H{sub 2} inventory, can be released throughout the complete hydrogen process chain. H{sub 2} enters the stratosphere via the tropical tropopause and is oxidised there to form water vapour (H{sub 2}O). This extra water vapour causes increased radiation in the infrared region of the electromagnetic spectrum and thus causes the stratosphere to cool down. Both the increase in H{sub 2}O and the resulting cooling down of the stratosphere encourage the formation of polar stratospheric clouds (PSC) and liquid sulphate aerosols, which facilitate the production of reactive chlorine, which in turn currently leads to dramatic ozone depletion in the polar stratosphere. In the future, H{sub 2} emissions from a global hydrogen economy could therefore encourage stratospheric ozone depletion in the polar regions and thus inhibit the ozone layer in recovering from the damage caused by chlorofluorocarbons (CFCs). In addition to estimating possible influences on the trace gas composition of the stratosphere, one of the main aims of this thesis is to evaluate the risk associated with increased polar ozone depletion caused by additional H{sub 2} emissions. Studies reported on here have shown that even if around 90% of today's fossil primary energy input was to be replaced by hydrogen and if around 9.5% of the gas was to escape in a ''worst-case'' scenario, the additional ozone loss for

  11. Comparison of Hydrogen Sulfide Analysis Techniques

    Science.gov (United States)

    Bethea, Robert M.

    1973-01-01

    A summary and critique of common methods of hydrogen sulfide analysis is presented. Procedures described are: reflectance from silver plates and lead acetate-coated tiles, lead acetate and mercuric chloride paper tapes, sodium nitroprusside and methylene blue wet chemical methods, infrared spectrophotometry, and gas chromatography. (BL)

  12. Screening analysis of solar thermochemical hydrogen concepts.

    Energy Technology Data Exchange (ETDEWEB)

    Diver, Richard B., Jr.; Kolb, Gregory J.

    2008-03-01

    A screening analysis was performed to identify concentrating solar power (CSP) concepts that produce hydrogen with the highest efficiency. Several CSP concepts were identified that have the potential to be much more efficient than today's low-temperature electrolysis technology. They combine a central receiver or dish with either a thermochemical cycle or high-temperature electrolyzer that operate at temperatures >600 C. The solar-to-hydrogen efficiencies of the best central receiver concepts exceed 20%, significantly better than the 14% value predicted for low-temperature electrolysis.

  13. Risks incurred by hydrogen escaping from containers and conduits

    Energy Technology Data Exchange (ETDEWEB)

    Swain, M.R.; Grilliot, E.S. [Univ. of Miami, Coral Gables, FL (United States); Swain, M.N. [Analytical Technologies, Inc., Miami, FL (United States)

    1998-08-01

    This paper is a discussion of a method for hydrogen leak classification. Leaks are classified as; gas escapes into enclosed spaces, gas escapes into partially enclosed spaces (vented), and gas escapes into unenclosed spaces. Each of the three enclosure classifications is further divided into two subclasses; total volume of hydrogen escaped and flow rate of escaping hydrogen. A method to aid in risk assessment determination in partially enclosed spaces is proposed and verified for several enclosure geometries. Examples are discussed for additional enclosure geometries.

  14. Information security risk analysis

    CERN Document Server

    Peltier, Thomas R

    2001-01-01

    Effective Risk AnalysisQualitative Risk AnalysisValue AnalysisOther Qualitative MethodsFacilitated Risk Analysis Process (FRAP)Other Uses of Qualitative Risk AnalysisCase StudyAppendix A: QuestionnaireAppendix B: Facilitated Risk Analysis Process FormsAppendix C: Business Impact Analysis FormsAppendix D: Sample of ReportAppendix E: Threat DefinitionsAppendix F: Other Risk Analysis OpinionsIndex

  15. Risk Analysis

    Science.gov (United States)

    Morring, Frank, Jr.

    2004-01-01

    A National Academies panel says the Hubble Space Telescope is too valuable ;or gamblingon a long-shot robotic mission to extend its service life, and urges Directly contradicting Administrator Sean O'Keefe, who killed a planned fifth shuttle servicing mission to the telescope on grounds it was too dangerous for a human crew in the post-Challenger environment, the expert committee found that upgrades to shuttle safety actually should make it less hazardous to fly to the telescope than it was before Columbia was lost. Risks of a telescope-servicing mission are only marginally greater than the planned missions to the International Space Station (ISS) O'Keefe has authorized, the panel found. After comparing those risks to the dangers inherent in trying to develop a complex space robot in the 39 months remaining in the Hubble s estimated service life, the panel opted for the human mission to save one of the major achievements of the American space program, in the words of Louis J. Lanzerotti, its chairman.

  16. Analysis of Hydrogen Bonds in Crystals

    Directory of Open Access Journals (Sweden)

    Sławomir J. Grabowski

    2016-05-01

    Full Text Available The determination of crystal structures provides important information on the geometry of species constituting crystals and on the symmetry relations between them. Additionally, the analysis of crystal structures is so conclusive that it allows us to understand the nature of various interactions. The hydrogen bond interaction plays a crucial role in crystal engineering and, in general, its important role in numerous chemical, physical and bio-chemical processes was the subject of various studies. That is why numerous important findings on the nature of hydrogen bonds concern crystal structures. This special issue presents studies on hydrogen bonds in crystals, and specific compounds and specific H-bonded patterns existing in crystals are analyzed. However, the characteristics of the H-bond interactions are not only analyzed theoretically; this interaction is compared with other ones that steer the arrangement of molecules in crystals, for example halogen, tetrel or pnicogen bonds. More general findings concerning the influence of the hydrogen bond on the physicochemical properties of matter are also presented.

  17. Estimation of Uncertainty in Risk Assessment of Hydrogen Applications

    DEFF Research Database (Denmark)

    Markert, Frank; Krymsky, V.; Kozine, Igor

    2011-01-01

    Hydrogen technologies such as hydrogen fuelled vehicles and refuelling stations are being tested in practice in a number of projects (e.g. HyFleet-Cute and Whistler project) giving valuable information on the reliability and maintenance requirements. In order to establish refuelling stations...... and extrapolations to be made. Therefore, the QRA results will contain varying degrees of uncertainty as some components are well established while others are not. The paper describes a methodology to evaluate the degree of uncertainty in data for hydrogen applications based on the bias concept of the total...... probability and the NUSAP concept to quantify uncertainties of new not fully qualified hydrogen technologies and implications to risk management....

  18. Thermal Analysis of Cryogenic Hydrogen Liquid Separator

    Science.gov (United States)

    Congiardo, Jared F.; Fortier, Craig R. (Editor)

    2014-01-01

    During launch for the new Space Launch System (SLS) liquid hydrogen is bleed through the engines during replenish, pre-press, and extended pre-press to condition the engines prior to launch. The predicted bleed flow rates are larger than for the shuttle program. A consequence of the increased flow rates is having liquif hydrogen in the vent system, which the facilities was never designed to handle. To remedy the problem a liquid separator is being designed in the system to accumulated the liquid propellant and protect the facility flare stack (which can only handle gas). The attached document is a presentation of the current thermalfluid analysis performed for the separator and will be presented at the Thermal and Fluid Analysis Workshop (NASA workshop) next week in Cleveland, Ohio.

  19. Research efforts for the resolution of hydrogen risk

    Directory of Open Access Journals (Sweden)

    Seong-Wan Hong

    2015-02-01

    Full Text Available During the past 10 years, the Korea Atomic Energy Research Institute (KAERI has performed a study to control hydrogen gas in the containment of the nuclear power plants. Before the Fukushima accident, analytical activities for gas distribution analysis in experiments and plants were primarily conducted using a multidimensional code: the GASFLOW. After the Fukushima accident, the COM3D code, which can simulate a multidimensional hydrogen explosion, was introduced in 2013 to complete the multidimensional hydrogen analysis system. The code validation efforts of the multidimensional codes of the GASFLOW and the COM3D have continued to increase confidence in the use of codes using several international experimental data. The OpenFOAM has been preliminarily evaluated for APR1400 containment, based on experience from coded validation and the analysis of hydrogen distribution and explosion using the multidimensional codes, the GASFLOW and the COM3D. Hydrogen safety in nuclear power has become a much more important issue after the Fukushima event in which hydrogen explosions occurred. The KAERI is preparing a large-scale test that can be used to validate the performance of domestic passive autocatalytic recombiners (PARs and can provide data for the validation of the severe accident code being developed in Korea.

  20. Research effects for the resolution of hydrogen risk

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seong Wan; Kim, Jong Tae; Kang, Hyung Seok; Na, Young Su; Song, Jin Ho [Division of Severe Accident and PHWR Safety Research, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-02-15

    During the past 10 years, the Korea Atomic Energy Research Institute (KAERI) has performed a study to control hydrogen gas in the containment of the nuclear power plants. Before the Fukushima accident, analytical activities for gas distribution analysis in experiments and plants were primarily conducted using a multidimensional code: the GASFLOW. After the Fukushima accident, the COM3D code, which can simulate a multidimensional hydrogen explosion, was introduced in 2013 to complete the multidimensional hydrogen analysis system. The code validation efforts of the multidimensional codes of the GASFLOW and the COM3D have continued to increase confidence in the use of codes using several international experimental data. The OpenFOAM has been preliminarily evaluated for APR1400 containment, based on experience from coded validation and the analysis of hydrogen distribution and explosion using the multidimensional codes, the GASFLOW and the COM3D. Hydrogen safety in nuclear power has become a much more important issue after the Fukushima event in which hydrogen explosions occurred. The KAERI is preparing a large-scale test that can be used to validate the performance of domestic passive autocatalytic recombiners (PARs) and can provide data for the validation of the severe accident code being developed in Korea.

  1. Final Report: Hydrogen Storage System Cost Analysis

    Energy Technology Data Exchange (ETDEWEB)

    James, Brian David [Strategic Analysis Inc., Arlington, VA (United States); Houchins, Cassidy [Strategic Analysis Inc., Arlington, VA (United States); Huya-Kouadio, Jennie Moton [Strategic Analysis Inc., Arlington, VA (United States); DeSantis, Daniel A. [Strategic Analysis Inc., Arlington, VA (United States)

    2016-09-30

    The Fuel Cell Technologies Office (FCTO) has identified hydrogen storage as a key enabling technology for advancing hydrogen and fuel cell power technologies in transportation, stationary, and portable applications. Consequently, FCTO has established targets to chart the progress of developing and demonstrating viable hydrogen storage technologies for transportation and stationary applications. This cost assessment project supports the overall FCTO goals by identifying the current technology system components, performance levels, and manufacturing/assembly techniques most likely to lead to the lowest system storage cost. Furthermore, the project forecasts the cost of these systems at a variety of annual manufacturing rates to allow comparison to the overall 2017 and “Ultimate” DOE cost targets. The cost breakdown of the system components and manufacturing steps can then be used to guide future research and development (R&D) decisions. The project was led by Strategic Analysis Inc. (SA) and aided by Rajesh Ahluwalia and Thanh Hua from Argonne National Laboratory (ANL) and Lin Simpson at the National Renewable Energy Laboratory (NREL). Since SA coordinated the project activities of all three organizations, this report includes a technical description of all project activity. This report represents a summary of contract activities and findings under SA’s five year contract to the US Department of Energy (Award No. DE-EE0005253) and constitutes the “Final Scientific Report” deliverable. Project publications and presentations are listed in the Appendix.

  2. FOOD RISK ANALYSIS

    Science.gov (United States)

    Food risk analysis is a holistic approach to food safety because it considers all aspects of the problem. Risk assessment modeling is the foundation of food risk analysis. Proper design and simulation of the risk assessment model is important to properly predict and control risk. Because of knowl...

  3. The risk of hydrogen explosion in a submarine p. IV The implementation of high risk projects

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard

    2017-06-01

    Full Text Available This series of articles on high risk projects looks at the example of the modernisation of hydrogen incinerators on a submarine. The article describes problems connected with the management of such a project.

  4. Analysis of Published Hydrogen Vehicle Safety Research

    Science.gov (United States)

    2010-02-01

    Hydrogen-fueled vehicles (HFVs) offer the promise of providing safe, clean, and efficient transportation in a setting of rising fuel prices and tightening environmental regulations. However, the technologies needed to store or manufacture hydrogen on...

  5. Foundations of Risk Analysis

    CERN Document Server

    Aven, Terje

    2012-01-01

    Foundations of Risk Analysis presents the issues core to risk analysis - understanding what risk means, expressing risk, building risk models, addressing uncertainty, and applying probability models to real problems. The author provides the readers with the knowledge and basic thinking they require to successfully manage risk and uncertainty to support decision making. This updated edition reflects recent developments on risk and uncertainty concepts, representations and treatment. New material in Foundations of Risk Analysis includes:An up to date presentation of how to understand, define and

  6. Analyses to support development of risk-informed separation distances for hydrogen codes and standards.

    Energy Technology Data Exchange (ETDEWEB)

    LaChance, Jeffrey L.; Houf, William G. (Sandia National Laboratories, Livermore, CA); Fluer, Inc., Paso Robels, CA; Fluer, Larry (Fluer, Inc., Paso Robels, CA); Middleton, Bobby

    2009-03-01

    The development of a set of safety codes and standards for hydrogen facilities is necessary to ensure they are designed and operated safely. To help ensure that a hydrogen facility meets an acceptable level of risk, code and standard development organizations are tilizing risk-informed concepts in developing hydrogen codes and standards.

  7. Analysis of Hybrid Hydrogen Systems: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Dean, J.; Braun, R.; Munoz, D.; Penev, M.; Kinchin, C.

    2010-01-01

    Report on biomass pathways for hydrogen production and how they can be hybridized to support renewable electricity generation. Two hybrid systems were studied in detail for process feasibility and economic performance. The best-performing system was estimated to produce hydrogen at costs ($1.67/kg) within Department of Energy targets ($2.10/kg) for central biomass-derived hydrogen production while also providing value-added energy services to the electric grid.

  8. Hydrogen storage and delivery system development: Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Handrock, J.L. [Sandia National Labs., Livermore, CA (United States)

    1996-10-01

    Hydrogen storage and delivery is an important element in effective hydrogen utilization for energy applications and is an important part of the FY1994-1998 Hydrogen Program Implementation Plan. This project is part of the Field Work Proposal entitled Hydrogen Utilization in Internal Combustion Engines (ICE). The goal of the Hydrogen Storage and Delivery System Development Project is to expand the state-of-the-art of hydrogen storage and delivery system design and development. At the foundation of this activity is the development of both analytical and experimental evaluation platforms. These tools provide the basis for an integrated approach for coupling hydrogen storage and delivery technology to the operating characteristics of potential hydrogen energy use applications. Results of the analytical model development portion of this project will be discussed. Analytical models have been developed for internal combustion engine (ICE) hybrid and fuel cell driven vehicles. The dependence of hydride storage system weight and energy use efficiency on engine brake efficiency and exhaust temperature for ICE hybrid vehicle applications is examined. Results show that while storage system weight decreases with increasing engine brake efficiency energy use efficiency remains relatively unchanged. The development, capability, and use of a recently developed fuel cell vehicle storage system model will also be discussed. As an example of model use, power distribution and control for a simulated driving cycle is presented. Model calibration results of fuel cell fluid inlet and exit temperatures at various fuel cell idle speeds, assumed fuel cell heat capacities, and ambient temperatures are presented. The model predicts general increases in temperature with fuel cell power and differences between inlet and exit temperatures, but under predicts absolute temperature values, especially at higher power levels.

  9. Hydrogen engine performance analysis. First annual report

    Energy Technology Data Exchange (ETDEWEB)

    Adt, Jr., R. R.; Swain, M. R.; Pappas, J. M.

    1978-08-01

    Many problems associated with the design and development of hydrogen-air breathing internal combustion engines for automotive applications have been identified by various domestic and foreign researchers. This project addresses the problems identified in the literature, seeks to evaluate potential solutions to these problems, and will obtain and document a design data-base convering the performance, operational and emissions characteristics essential for making rational decisions regarding the selection and design of prototype hydrogen-fueled, airbreathing engines suitable for manufacture for general automotive use. Information is included on the operation, safety, emission, and cost characteristics of hydrogen engines, the selection of a test engine and testing facilities, and experimental results. Baseline data for throttled and unthrottled, carburetted, hydrogen engine configurations with and without exhaust gas recirculation and water injection are presented. In addition to basic data gathering concerning performance and emissions, the test program conducted was formulated to address in detail the two major problems that must be overcome if hydrogen-fueled engines are to become viable: flashback and comparatively high NO/sub x/ emissions at high loads. In addition, the results of other hydrogen engine investigators were adjusted, using accepted methods, in order to make comparisons with the results of the present study. The comparisons revealed no major conflicts. In fact, with a few exceptions, there was found to be very good agreement between the results of the various studies.

  10. [Practical risk analysis].

    Science.gov (United States)

    Lisbona, A; Valero, M

    2015-10-01

    Risk analysis is typically considered from two complementary points of view: predictive analysis performed prior, and retrospective analysis, which follows the internal reporting of adverse situations or malfunctions, both on the organizational and material or human aspects. The purpose of these additional analyzes is to ensure that planned or implemented measures allow to keep risks to a level deemed tolerable or acceptable at a given time and in a given situation. Where a risk is deemed unacceptable, risk reduction measures should be considered (prevention, limiting the consequences and protection). Copyright © 2015. Published by Elsevier SAS.

  11. Risk analysis methodology survey

    Science.gov (United States)

    Batson, Robert G.

    1987-01-01

    NASA regulations require that formal risk analysis be performed on a program at each of several milestones as it moves toward full-scale development. Program risk analysis is discussed as a systems analysis approach, an iterative process (identification, assessment, management), and a collection of techniques. These techniques, which range from simple to complex network-based simulation were surveyed. A Program Risk Analysis Handbook was prepared in order to provide both analyst and manager with a guide for selection of the most appropriate technique.

  12. Hydrogen Technical Analysis -- Dissemination of Information

    Energy Technology Data Exchange (ETDEWEB)

    George Kervitsky, Jr.

    2006-03-20

    SENTECH is a small energy and environmental consulting firm providing technical, analytical, and communications solutions to technology management issues. The activities proposed by SENTECH focused on gathering and developing communications materials and information, and various dissemination activities to present the benefits of hydrogen energy to a broad audience while at the same time establishing permanent communications channels to enable continued two-way dialog with these audiences in future years. Effective communications and information dissemination is critical to the acceptance of new technology. Hydrogen technologies face the additional challenge of safety preconceptions formed primarily as a result of the crash of the Hindenburg. Effective communications play a key role in all aspects of human interaction, and will help to overcome the perceptual barriers, whether of safety, economics, or benefits. As originally proposed SENTECH identified three distinct information dissemination activities to address three distinct but important audiences; these formed the basis for the task structure used in phases 1 and 2. The tasks were: (1) Print information--Brochures that target the certain segment of the population and will be distributed via relevant technical conferences and traditional distribution channels. (2) Face-to-face meetings--With industries identified to have a stake in hydrogen energy. The three industry audiences are architect/engineering firms, renewable energy firms, and energy companies that have not made a commitment to hydrogen (3) Educational Forums--The final audience is students--the future engineers, technicians, and energy consumers. SENTECH will expand on its previous educational work in this area. The communications activities proposed by SENTECH and completed as a result of this cooperative agreement was designed to compliment the research and development work funded by the DOE by presenting the technical achievements and validations

  13. Hydrogen Pressurization of LOX: High Risk/High Reward (Preprint)

    National Research Council Canada - National Science Library

    Turner, Andrew E; Leichner, Aaron

    2006-01-01

    ... filled with hydrogen gas. Airship commercial service, enabled by relatively low-cost hydrogen, died along with the longest vehicle ever to fly, even though thousands of passengers had been transported without incident prior to that time...

  14. ITS risk analysis.

    Science.gov (United States)

    1996-06-01

    Risk analysis plays a key role in the implementation of an architecture. Early definition of the situations, : processes, or events that have the potential for impeding the implementation of key elements of the ITS : National Architecture is a critic...

  15. Spectrum analysis of hydrogen plasma in spherically convergent beam fusion

    Energy Technology Data Exchange (ETDEWEB)

    Ogasawara, Kazuki; Yamauchi, Kunihito; Watanabe, Masato; Sunaga, Yoshitaka; Hotta, Eiki [Tokyo Institute of Technology, Dept. of Energy Sciences, Yokohama, Kanagawa (Japan); Okino, Akitoshi [Tokyo Institute of Technology, Dept. of Electrical and Electronic Engineering, Tokyo (Japan)

    2001-09-01

    Spectroscopic analysis of spherical glow discharge fusion device was carried out using hydrogen gas. Effects of the discharge current and cathode voltage on spectrum profiles of hydrogen Balmar lines were measured. The profiles of all hydrogen lines were broadened with the cathode voltage. From the relationship between the maximum broadening width and the cathode voltage, it was indicated that the broadening was caused by the Doppler effect. From the spatial distribution of emission intensity, it was found that plasma core size became larger with discharge current and smaller with cathode voltage. (author)

  16. Program risk analysis handbook

    Science.gov (United States)

    Batson, R. G.

    1987-01-01

    NASA regulations specify that formal risk analysis be performed on a program at each of several milestones. Program risk analysis is discussed as a systems analysis approach, an iterative process (identification, assessment, management), and a collection of techniques. These techniques, which range from extremely simple to complex network-based simulation, are described in this handbook in order to provide both analyst and manager with a guide for selection of the most appropriate technique. All program risk assessment techniques are shown to be based on elicitation and encoding of subjective probability estimates from the various area experts on a program. Techniques to encode the five most common distribution types are given. Then, a total of twelve distinct approaches to risk assessment are given. Steps involved, good and bad points, time involved, and degree of computer support needed are listed. Why risk analysis should be used by all NASA program managers is discussed. Tools available at NASA-MSFC are identified, along with commercially available software. Bibliography (150 entries) and a program risk analysis check-list are provided.

  17. Ab initio charge analysis of pure and hydrogenated perovskites

    DEFF Research Database (Denmark)

    Bork, Nicolai Christian; Bonanos, Nikolaos; Rossmeisl, Jan

    2011-01-01

    We present a density functional theory based Bader analysis on the charge distribution in pure and hydrogenated SrTiO3. We find the hydrogen defect carries a +0.56e charge and the OH defect carrying a +0.50e charge compared to the host oxygen. Calculations on BaNbO3, CaTiO3, and SrZrO3 support th...

  18. Analysis of experimental hydrogen engine data and hydrogen vehicle performance and emissions simulation

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S.A. [Lawrence Livermore National Lab., CA (United States)

    1996-10-01

    This paper reports the engine and vehicle simulation and analysis done at Lawrence Livermore (LLNL) as a part of a joint optimized hydrogen engine development effort. Project participants are: Sandia National Laboratory; Los Alamos National Laboratory; and the University of Miami. Fuel cells are considered as the ideal power source for future vehicles, due to their high efficiency and low emissions. However, extensive use of fuel cells in light-duty vehicles is likely to be years away, due to their high manufacturing cost. Hydrogen-fueled, spark-ignited, homogeneous-charge engines offer a near-term alternative to fuel cells. Hydrogen in a spark-ignited engine can be burned at very low equivalence ratios. NO{sub x} emissions can be reduced to less than 10 ppm without catalyst. HC and CO emissions may result from oxidation of engine oil, but by proper design are negligible (a few ppm). Lean operation also results in increased indicated efficiency due to the thermodynamic properties of the gaseous mixture contained in the cylinder. The high effective octane number of hydrogen allows the use of a high compression ratio, further increasing engine efficiency. In this paper, a simplified engine model is used for predicting hydrogen engine efficiency and emissions. The model uses basic thermodynamic equations for the compression and expansion processes, along with an empirical correlation for heat transfer, to predict engine indicated efficiency. A friction correlation and a supercharger/turbocharger model are then used to calculate brake thermal efficiency. The model is validated with many experimental points obtained in a recent evaluation of a hydrogen research engine. The experimental data are used to adjust the empirical constants in the heat release rate and heat transfer correlation. The results indicate that hydrogen lean-burn spark-ignite engines can provide Equivalent Zero Emission Vehicle (EZEV) levels in either a series hybrid or a conventional automobile.

  19. Hydrogen embrittlement II. Analysis of hydrogen-enhanced decohesion across (111) planes in α -Fe

    Science.gov (United States)

    Katzarov, Ivaylo H.; Paxton, Anthony T.

    2017-08-01

    This is the second of two papers that present a theoretical analysis of the phenomenon of hydrogen embrittlement of α -Fe. We make contact between the thermodynamic-kinetic continuum and cohesive zone models and the quantum-mechanical magnetic tight-binding approximation to interatomic forces. We are able to solve a coupled set of equations using quantum mechanically obtained atomistic data to follow the decohesion process in time as traction is applied to a hydrogen charged crystal and decohesion occurs between two (111) crystal planes. This scheme will be readily extended from transgranular to intergranular failure, although the complexities of the trapping sites in the cohesive zone associated with a grain boundary will greatly complicate the calculation of the configurational energy. Hydrogen-enhanced decohesion postulated widely in the field has not yet been demonstrated experimentally, although our calculations find a reduction in the ideal cohesive strength as a result of dissolved hydrogen in α -Fe from 30 to 22 GPa. Because of the well-known steep and nonlinear relation between plastic and ideal elastic work of fracture, this represents a very significant reduction in toughness as a result of a hydrogen concentration of less than ten atomic parts per million.

  20. Hydrogen Safety Sensor Performance and Use Gap Analysis: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Buttner, William J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Burgess, Robert M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Schmidt, Kara [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hartmann, Kevin S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wright, Hannah [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Weidner, Eveline [Joint Research Centre, Petten, the Netherlands; Cebolla, Rafael O. [Joint Research Centre, Petten, the Netherlands; Bonato, Christian [Joint Research Centre, Petten, the Netherlands; Moretto, Pietro [Joint Research Centre, Petten, the Netherlands

    2017-11-15

    Hydrogen sensors are recognized as an important technology for facilitating the safe implementation of hydrogen as an alternative fuel, and there are numerous reports of a sensor alarm successfully preventing a potentially serious event. However, gaps in sensor metrological specifications, as well as in their performance for some applications, exist.The U.S. Department of Energy (DOE) Fuel Cell Technology Office published a short list of critical gaps in the 2007 and 2012 multiyear project plans; more detailed gap analyses were independently performed by the JRC and NREL. There have been, however, some significant advances in sensor technologies since these assessments, including the commercial availability of hydrogen sensors with fast response times (t90 less than 1 s, which had been an elusive DOE target since 2007), improved robustness to chemical poisons, improved selectivity, and improved lifetime and stability. These improvements, however, have not been universal and typically pertain to select platforms or models. Moreover, as hydrogen markets grow and new applications are being explored, more demands will be imposed on sensor performance. The hydrogen sensor laboratories at NREL and JRC are currently updating the hydrogen safety sensor gap analysis through direct interaction with international stakeholders in the hydrogen community, especially end-users. NREL and the JRC are currently organizing a series of workshops (in Europe and the U.S.) with sensor developers, end-users, and other stakeholders in 2017 to identify technology gaps and to develop a path forward to address them. One workshop is scheduled for May 10 in Brussels, Belgium at the Headquarters of the Fuel Cell and Hydrogen Joint Undertaking. A second workshop is planned at the National Renewable Energy Laboratory in Golden, CO, USA. This presentation will review improvements in sensor technologies in the past 5 to 10 years, identify gaps in sensor performance and use requirements, and identify

  1. Uncertainties in explosion risk assessment for a hydrogen refueling station

    NARCIS (Netherlands)

    Ham, J.M.; Maaijer, M. de; Hoogenband, V. van den; Dam, C.E.C.; Weeda, M.; Reijerkerk, J.; Kramer, G.J.

    2011-01-01

    The project “Towards a Hydrogen Refueling Infrastructure for Vehicles” (THRIVE) aimed at the determination of conditions to stimulate the building of a sustainable infrastructure for hydrogen as a car fuel in The Netherlands. Economic scenarios were constructed for the development of such an

  2. Hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Pier, M.

    1943-02-19

    A transcript is presented of a speech on the history of the development of hydrogenation of coal and tar. Apparently the talk had been accompanied by the showing of photographic slides, but none of the pictures were included with the report. In giving the history, Dr. Pier mentioned the dependence of much of the development of hydrogenation upon previous development in the related areas of ammonia and methanol syntheses, but he also pointed out several ways in which equipment appropriate for hydrogenation differed considerably from that used for ammonia and methanol. Dr. Pier discussed the difficulties encountered with residue processing, design of the reaction ovens, manufacture of ovens and preheaters, heating of reaction mixtures, development of steels, and development of compressor pumps. He described in some detail his own involvement in the development of the process. In addition, he discussed the development of methods of testing gasolines and other fuels. Also he listed some important byproducts of hydrogenation, such as phenols and polycyclic aromatics, and he discussed the formation of iso-octane fuel from the butanes arising from hydrogenation. In connection with several kinds of equipment used in hydrogenation (whose pictures were being shown), Dr. Pier gave some of the design and operating data.

  3. Risk Analysis of Marine Structures

    DEFF Research Database (Denmark)

    Hansen, Peter Friis

    1998-01-01

    Basic concepts of risk analysis is introduced. Formulation and analysis of fault and event trees are treated.......Basic concepts of risk analysis is introduced. Formulation and analysis of fault and event trees are treated....

  4. ANALYSIS OF AVAILABLE HYDROGEN DATA & ACCUMULATION OF HYDROGEN IN UNVENTED TRANSURANIC (TRU) DRUMS

    Energy Technology Data Exchange (ETDEWEB)

    DAYLEY, L

    2004-06-24

    This document provides a response to the second action required in the approval for the Justification for Continued Operations (JCO) Assay and Shipment of Transuranic (TRU) Waste Containers in 218-W-4C. The Waste Management Project continues to make progress toward shipping certified TRU waste to the Waste Isolation Pilot Plant (WIPP). As the existing inventory of TRU waste in the Central Waste Complex (CWC) storage buildings is shipped, and the uncovered inventory is removed from the trenches and prepared for shipment from the Hanford Site, the covered inventory of suspect TRU wastes must be retrieved and prepared for processing for shipment to WIPP. Accumulation of hydrogen in unvented TRU waste containers is a concern due to the possibility of explosive mixtures of hydrogen and oxygen. The frequency and consequence of these gas mixtures resulting in an explosion must be addressed. The purpose of this study is to recommend an approach and schedule for venting TRU waste containers in the low-level burial ground (LLBG) trenches in conjunction with TRU Retrieval Project activities. This study provides a detailed analysis of the expected probability of hydrogen gas accumulation in significant quantities in unvented drums. Hydrogen gas accumulation in TRU drums is presented and evaluated in the following three categories: Hydrogen concentrations less than 5 vol%; Hydrogen between 5-15 vol%; and Hydrogen concentrations above 15 vol%. This analysis is based on complex-wide experience with TRU waste drums, available experimental data, and evaluations of storage conditions. Data reviewed in this report includes experience from the Idaho National Environmental Engineering Laboratories (INEEL), Savannah River Site (SRS), Los Alamos National Laboratories (LANL), Oak Ridge National Laboratories, (ORNL), Rocky Flats sites, Matrix Depletion Program and the National Transportation and Packaging Program. Based on this analysis, as well as an assessment of the probability and

  5. Quantifying and Addressing the DOE Material Reactivity Requirements with Analysis and Testing of Hydrogen Storage Materials & Systems

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Y. F. [United Technologies Research Center (UTRC), East Hartford, CT (United States)

    2012-04-30

    The objective of this project is to examine safety aspects of candidate hydrogen storage materials and systems being developed in the DOE Hydrogen Program. As a result of this effort, the general DOE safety target will be given useful meaning by establishing a link between the characteristics of new storage materials and the satisfaction of safety criteria. This will be accomplished through the development and application of formal risk analysis methods, standardized materials testing, chemical reactivity characterization, novel risk mitigation approaches and subscale system demonstration. The project also will collaborate with other DOE and international activities in materials based hydrogen storage safety to provide a larger, highly coordinated effort.

  6. Analysis of hydrogen as a Transportation Fuel FY17 Report

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, Richard M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Luzi, Francesco [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wilcox Freeburg, Eric D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-09-30

    This report summarizes the results of literature reviews, surveys and analyses performed to evaluate the potential of hydrogen-fueled vehicles to be an economically viable transportation alternative. Five existing and important drivers of expanding hydrogen-fueled transportation adoption are multi-billion dollar sales reservations of Nikola Class 8 trucks, CALSTART viability analysis of hybrid-hydrogen drayage trucks in the shipyard cargo application, analysis showing economic advantages of Fuel Cell Electric Vehicles (FCEV)s over Battery Electric Vehicles (BEV)s beginning at 150-mile ranges, the announcement of a commercial 5kg electrolyzer, and commercial plans or vehicle availability by nine vehicle manufacturers of FCEV passenger vehicles. But hydrogen infrastructure availability needed to support broad adoption of hydrogen-fueled vehicles is limited to less than 50 publicly-available refueling stations, primarily in California. The demand side (consumer) economics associated with FCEV adoption showed strong economic sensitivity to the original vehicle’s fuel economy (mpg), distance traveled, and hydrogen (H2) generation costs. Seven use cases were used to evaluate the broad range of potential FCEV purchasers, including autonomous vehicle applications. Each consumer use case analysis resulted in a different hydrogen fuel cost that would be equivalent to the current fuel cost being paid by the consumer. The H2 generation costs (supply side) were sensitive to the volume of H2 supplied and H2 production costs needed to repay H2 supply facility capital costs and produce competitively-priced energy. H2FAST was used to more accurately incorporate capital, maintenance and production costs into a viable H2 supply cost to the consumer. When the H2 generation and consumer economics were combined, several applications with positive economics became clear. The availability of low-cost hydrogen pipeline connections, and therefore low-cost hydrogen, greatly benefits the

  7. Analysis of experimental hydrogen engine data and hydrogen vehicle performance and emissions simulation

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S.M.

    1996-09-01

    This paper reports the engine and vehicle simulation and analysis done at Lawrence Livermore (LLNL) as a part of a joint optimized hydrogen engine development effort. Project participants are: Sandia National Laboratory, California (SNLC), responsible for experimental evaluation; Los Alamos National Laboratory (LANL), responsible for detailed fluid mechanics engine evaluations, and the University of Miami, responsible for engine friction reduction. Fuel cells are considered as the ideal power source for future vehicles, due to their high efficiency and low emissions. However, extensive use of fuel cells in light-duty vehicles is likely to be years away, due to their high manufacturing cost. Hydrogen-fueled, spark-ignited, homogeneous-charge engines offer a near-term alternative to fuel cells. Hydrogen in a spark-ignited engine can be burned at very low equivalence ratios, so that NO{sub x} emissions can be reduced to less than 10 ppm without catalyst. HC and CO emissions may result from oxidation of engine oil, but by proper design are negligible (a few ppm). Lean operation also results in increased indicated efficiency due to the thermodynamic properties of the gaseous mixture contained in the cylinder. The high effective octane number of hydrogen allows the use of a high compression ratio, further increasing engine efficiency.

  8. Analysis of hypothetical geothermal hydrogen systems in Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Melaina, Marc; Penev, Mike [National Renewable Energy Lab. (NREL), Golden, CO (United States); Devlin, Peter [U.S. Department of Energy, Rockville, MD (United States)

    2010-07-01

    Analysis is presented for three theoretical geothermal energy systems on the Big Island of Hawaii. This preliminary study evaluates performance and economics for several strategies for enhancing integration of a geothermal renewable resource into the grid and for producing vehicle fuel by way of hydrogen production and storage. The analysis includes production of hydrogen and ammonia for use as fuels in light duty vehicles, and production of peak power using hydrogen produced off-peak, stored, and later use in a steam turbine to produce electricity during peak demand. Technological performance and costs are assessed for a near-term installation (next 2-3 years) and are compared on an apples-to-apples basis using consistent economic assumptions for two key metrics: (1) the ratio of geothermal energy product costs to comparable commodity prices, and (2) fuel costs per mile. (orig.)

  9. Analysis of electro-permeation of hydrogen in metallic alloys.

    Science.gov (United States)

    Raina, A; Deshpande, V S; Fleck, N A

    2017-07-28

    A reaction-diffusion type modelling framework is presented to analyse both electro-permeation (EP) and thermal desorption spectrometry (TDS) measurements of hydrogen in metallic alloys. It is assumed that the kinetics of hydrogen motion is governed by diffusion through the lattice, along with trapping/detrapping at specific sites such as dislocations, grain boundaries, etc. It is shown that the trapping and detrapping rates are typically much faster than the diffusion rate, and consequently a simplification of the governing equations suffices such that local equilibrium exists between lattice and trapped hydrogen. Using this local equilibrium assumption, we then present an asymptotic analysis of the governing kinetic equation for the EP test. This asymptotic analysis reveals that four regimes of behaviour exist, ranging from negligible trapping to the complete filling of deep traps. The analysis suggests that EP tests should be so-arranged that three regimes of behaviour are spanned, in order to extract the relevant material properties associated with hydrogen transport. The numerical solutions presented in this study support the asymptotic analysis. The hydrogen kinetics framework is also deployed to analyse both EP and TDS tests on the same martensitic steel. The EP measurements all lie in regime I and are thus insufficient to uniquely determine both the trap density and binding energy. Reasonable agreement is obtained between measurements and numerical predictions of TDS tests using parameters estimated from the EP tests. Further improvements in measurements are required to confirm the fidelity of this modelling approach.This article is part of the themed issue 'The challenges of hydrogen and metals'. © 2017 The Author(s).

  10. Hydrogen.

    Science.gov (United States)

    Bockris, John O'M

    2011-11-30

    The idea of a "Hydrogen Economy" is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO₂ in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H₂ from the electrolyzer. Methanol made with CO₂ from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan). Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs) by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  11. Safety risks of hydrogen fuel for applications in transportation vehicles.

    Science.gov (United States)

    2009-04-01

    Combustion of hydrocarbon fuels in many practical applications produces pollutants that are harmful to human health and environment. Hydrogen fuel is considered to be a potential answer to the clean energy demands, especially with the advances in fue...

  12. U.S. Department of Energy Hydrogen Storage Cost Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Law, Karen; Rosenfeld, Jeffrey; Han, Vickie; Chan, Michael; Chiang, Helena; Leonard, Jon

    2013-03-11

    The overall objective of this project is to conduct cost analyses and estimate costs for on- and off-board hydrogen storage technologies under development by the U.S. Department of Energy (DOE) on a consistent, independent basis. This can help guide DOE and stakeholders toward the most-promising research, development and commercialization pathways for hydrogen-fueled vehicles. A specific focus of the project is to estimate hydrogen storage system cost in high-volume production scenarios relative to the DOE target that was in place when this cost analysis was initiated. This report and its results reflect work conducted by TIAX between 2004 and 2012, including recent refinements and updates. The report provides a system-level evaluation of costs and performance for four broad categories of on-board hydrogen storage: (1) reversible on-board metal hydrides (e.g., magnesium hydride, sodium alanate); (2) regenerable off-board chemical hydrogen storage materials(e.g., hydrolysis of sodium borohydride, ammonia borane); (3) high surface area sorbents (e.g., carbon-based materials); and 4) advanced physical storage (e.g., 700-bar compressed, cryo-compressed and liquid hydrogen). Additionally, the off-board efficiency and processing costs of several hydrogen storage systems were evaluated and reported, including: (1) liquid carrier, (2) sodium borohydride, (3) ammonia borane, and (4) magnesium hydride. TIAX applied a bottom-up costing methodology customized to analyze and quantify the processes used in the manufacture of hydrogen storage systems. This methodology, used in conjunction with ® software and other tools, developed costs for all major tank components, balance-of-tank, tank assembly, and system assembly. Based on this methodology, the figure below shows the projected on-board high-volume factory costs of the various analyzed hydrogen storage systems, as designed. Reductions in the key cost drivers may bring hydrogen storage system costs closer to this DOE target

  13. Heat transfer analysis of liquid piston compressor for hydrogen applications

    DEFF Research Database (Denmark)

    Kermani, Nasrin Arjomand; Rokni, Masoud

    2015-01-01

    A hydrogen compression technology using liquid as the compression piston is investigated from heat transfer point of view. A thermodynamic model, simulating a single compression stroke, is developed to investigate the heat transfer phenomena inside the compression chamber. The model is developed...... and through the walls, is investigated and compared with the adiabatic case. The results show that depending on heat transfer correlation, the hydrogen temperature reduces slightly between 0.2% and 0.4% compared to the adiabatic case, at 500bar, due to the large wall resistance and small contact area...... at the interface. Moreover, the results of the sensitivity analysis illustrates that increasing the total heat transfer coefficients at the interface and the wall, together with compression time, play key roles in reducing the hydrogen temperature. Increasing the total heat transfer coefficient at the interface...

  14. Hydrogen

    Directory of Open Access Journals (Sweden)

    John O’M. Bockris

    2011-11-01

    Full Text Available The idea of a “Hydrogen Economy” is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO2 in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H2 from the electrolyzer. Methanol made with CO2 from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan. Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  15. Technical analysis of photovoltaic/wind systems with hydrogen storage

    OpenAIRE

    Bakić Vukman V.; Pezo Milada L.; Jovanović Marina P.; Turanjanin Valentina M.; Vučićević Biljana S.

    2012-01-01

    The technical analysis of a hybrid wind-photovoltaic energy system with hydrogen gas storage was studied. The market for the distributed power generation based on renewable energy is increasing, particularly for the standalone mini-grid applications. The main design components of PV/Wind hybrid system are the PV panels, the wind turbine and an alkaline electrolyzer with tank. The technical analysis is based on the transient system simulation program TRNSYS 16. The study is realized usin...

  16. Hydrogen and Water: An Engineering, Economic and Environmental Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Simon, A J; Daily, W; White, R G

    2010-01-06

    The multi-year program plan for the Department of Energy's Hydrogen and Fuel Cells Technology Program (USDOE, 2007a) calls for the development of system models to determine economic, environmental and cross-cutting impacts of the transition to a hydrogen economy. One component of the hydrogen production and delivery chain is water; water's use and disposal can incur costs and environmental consequences for almost any industrial product. It has become increasingly clear that due to factors such as competing water demands and climate change, the potential for a water-constrained world is real. Thus, any future hydrogen economy will need to be constructed so that any associated water impacts are minimized. This, in turn, requires the analysis and comparison of specific hydrogen production schemes in terms of their water use. Broadly speaking, two types of water are used in hydrogen production: process water and cooling water. In the production plant, process water is used as a direct input for the conversion processes (e.g. steam for Steam Methane Reforming {l_brace}SMR{r_brace}, water for electrolysis). Cooling water, by distinction, is used indirectly to cool related fluids or equipment, and is an important factor in making plant processes efficient and reliable. Hydrogen production further relies on water used indirectly to generate other feedstocks required by a hydrogen plant. This second order indirect water is referred to here as 'embedded' water. For example, electricity production uses significant quantities of water; this 'thermoelectric cooling' contributes significantly to the total water footprint of the hydrogen production chain. A comprehensive systems analysis of the hydrogen economy includes the aggregate of the water intensities from every step in the production chain including direct, indirect, and embedded water. Process and cooling waters have distinct technical quality requirements. Process water, which is typically

  17. Risk Perception of an Emergent Technology: The Case of Hydrogen Energy

    Directory of Open Access Journals (Sweden)

    Rob Flynn

    2006-01-01

    Full Text Available Although hydrogen has been used in industry for many years as a chemical commodity, its use as a fuel or energy carrier is relatively new and expert knowledge about its associated risks is neither complete nor consensual. Public awareness of hydrogen energy and attitudes towards a future hydrogen economy are yet to be systematically investigated. This paper opens by discussing alternative conceptualisations of risk, then focuses on issues surrounding the use of emerging technologies based on hydrogen energy. It summarises expert assessments of risks associated with hydrogen. It goes on to review debates about public perceptions of risk, and in doing so makes comparisons with public perceptions of other emergent technologies—Carbon Capture and Storage (CCS, Genetically Modified Organisms and Food (GM and Nanotechnology (NT—for which there is considerable scientific uncertainty and relatively little public awareness. The paper finally examines arguments about public engagement and "upstream" consultation in the development of new technologies. It is argued that scientific and technological uncertainties are perceived in varying ways and different stakeholders and different publics focus on different aspects or types of risk. Attempting to move public consultation further "upstream" may not avoid this, because the framing of risks and benefits is necessarily embedded in a cultural and ideological context, and is subject to change as experience of the emergent technology unfolds. URN: urn:nbn:de:0114-fqs0601194

  18. Elastic recoil detection analysis of hydrogen in polymers

    Energy Technology Data Exchange (ETDEWEB)

    Winzell, T.R.H.; Whitlow, H.J. [Lund Univ. (Sweden); Bubb, I.F.; Short, R.; Johnston, P.N. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1996-12-31

    Elastic recoil detection analysis (ERDA) of hydrogen in thick polymeric films has been performed using 2.5 MeV He{sup 2+} ions from the tandem accelerator at the Royal Melbourne Institute of Technology. The technique enables the use of the same equipment as in Rutherford backscattering analysis, but instead of detecting the incident backscattered ion, the lighter recoiled ion is detected at a small forward angle. The purpose of this work is to investigate how selected polymers react when irradiated by helium ions. The polymers are to be evaluated for their suitability as reference standards for hydrogen depth profiling. Films investigated were Du Pont`s Kapton and Mylar, and polystyrene. 11 refs., 3 figs.

  19. Risk Analysis in Investment Appraisal

    OpenAIRE

    Savvides, Savvakis C.

    1994-01-01

    This paper was prepared for the purpose of presenting the methodology and uses of the Monte Carlo simulation technique as applied in the evaluation of investment projects to analyse and assess risk. The first part of the paper highlights the importance of risk analysis in investment appraisal. The second part presents the various stages in the application of the risk analysis process. The third part examines the interpretation of the results generated by a risk analysis application including ...

  20. Hydrogen Trailer Storage Facility (Building 878). Consequence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Banda, Z.; Wood, C.L.

    1994-12-01

    The Department of Energy Order 5500.3A requires facility-specific hazards assessments be prepared, maintained, and used for emergency planning purposes. This consequence analysis documents the impact that a hydrogen accident could have to employees, the general public, and nearby facilities. The computer model ARCHIE was utilized to determine discharge rates, toxic vapor dispersion analyses, flammable vapor cloud hazards, explosion hazards, and flame jets for the Hydrogen Trailer Storage Facility located at Building 878. To determine over pressurization effects, hand calculations derived from the Department of the Air Force Manual, ``Structures to Resist the Effects of Accidental Explosions,`` were utilized. The greatest distances at which a postulated facility event will produce the Lower Flammability and the Lower Detonation Levels are 1,721 feet and 882 feet, respectively. The greatest distance at which 10.0 psi overpressure (i.e., total building destruction) is reached is 153 feet.

  1. Estimation of Hydrogen-Exchange Protection Factors from MD Simulation Based on Amide Hydrogen Bonding Analysis

    Science.gov (United States)

    Park, In-Hee; Venable, John D.; Steckler, Caitlin; Cellitti, Susan E.; Lesley, Scott A.; Spraggon, Glen; Brock, Ansgar

    2015-01-01

    Hydrogen exchange (HX) studies have provided critical insight into our understanding of protein folding, structure and dynamics. More recently, Hydrogen Exchange Mass Spectrometry (HX-MS) has become a widely applicable tool for HX studies. The interpretation of the wealth of data generated by HX-MS experiments as well as other HX methods would greatly benefit from the availability of exchange predictions derived from structures or models for comparison with experiment. Most reported computational HX modeling studies have employed solvent-accessible-surface-area based metrics in attempts to interpret HX data on the basis of structures or models. In this study, a computational HX-MS prediction method based on classification of the amide hydrogen bonding modes mimicking the local unfolding model is demonstrated. Analysis of the NH bonding configurations from Molecular Dynamics (MD) simulation snapshots is used to determine partitioning over bonded and non-bonded NH states and is directly mapped into a protection factor (PF) using a logistics growth function. Predicted PFs are then used for calculating deuteration values of peptides and compared with experimental data. Hydrogen exchange MS data for Fatty acid synthase thioesterase (FAS-TE) collected for a range of pHs and temperatures was used for detailed evaluation of the approach. High correlation between prediction and experiment for observable fragment peptides is observed in the FAS-TE and additional benchmarking systems that included various apo/holo proteins for which literature data were available. In addition, it is shown that HX modeling can improve experimental resolution through decomposition of in-exchange curves into rate classes, which correlate with prediction from MD. Successful rate class decompositions provide further evidence that the presented approach captures the underlying physical processes correctly at the single residue level. This assessment is further strengthened in a comparison of

  2. An analysis of hydrogen production from ammonia hydride hydrogen generators for use in military fuel cell environments

    Science.gov (United States)

    Sifer, Nicholas; Gardner, Kristopher

    In an effort to simultaneously improve upon existing power storage and generation devices while supplying America's war fighters with state-of-the-art equipment, the US military has focused on fuel cell technology for several military applications. These applications include soldier and sensor power (0-100 W) and auxiliary power units (500-3000 W). Over the past few years, the fuel cell industry has realized remarkable decreases in the size and weight of proton exchange membrane (PEM) fuel cell systems. However, a safe and affordable means of storing and generating hydrogen does not yet exist to justify their transition into the field. In order to assess the hydrogen storage capacity and hydrogen generation rates of ammonia (NH 3) based systems, the US Army Communications-Electronics Research, Development, and Engineering Center (CERDEC), tested several ammonia hydride hydrogen generator systems built by Hydrogen Components Inc. (HCI). Experimental results and analysis illustrate that while there are developments necessary at the sub-system level, the hydrogen generators are ideal energy storage devices for low power (5 W) operations over wide temperature ranges. The results show that the hydrogen generators are capable of operating autonomously for over 50+ h of operation (at a 5 W load) and producing hydrogen delivery system energy densities of 480 Wh/kg.

  3. Macro-System Model for Hydrogen Energy Systems Analysis in Transportation: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Diakov, V.; Ruth, M.; Sa, T. J.; Goldsby, M. E.

    2012-06-01

    The Hydrogen Macro System Model (MSM) is a simulation tool that links existing and emerging hydrogen-related models to perform rapid, cross-cutting analysis. It allows analysis of the economics, primary energy-source requirements, and emissions of hydrogen production and delivery pathways.

  4. Insights from Hydrogen Refueling Station Manufacturing Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mayyas, Ahmad

    2015-12-18

    In work for the Clean Energy Manufacturing Analysis Center (CEMAC), NREL is currently collaborating with Great Lakes Wind Network in conducting a comprehensive hydrogen refueling stations manufacturing competitiveness and supply chain analyses. In this project, CEMAC will be looking at several metrics that will facilitate understanding of the interactions between and within the HRS supply chain, such metrics include innovation potential, intellectual properties, learning curves, related industries and clustering, existing supply chains, ease of doing business, and regulations and safety. This presentation to Fuel Cell Seminar and Energy Exposition 2015 highlights initial findings from CEMAC's analysis.

  5. RISK ANALYSIS SERIES. PART ONE - WHY RISK ANALYSIS?

    OpenAIRE

    Iulian N. BUJOREANU

    2012-01-01

    The goal of this paper is to introduce the reader to the Risk Analysis Series to be developed in the pages of the Journal of Defense Resources Management. Risk analysis is of outmost importance in dealing with resource allocation and this is the reason the paper’s author started this series. Different views and approaches will be added during further discussion about risk analysis so that the reader develops a habit or skills of dealing with this intricate and challenging field.

  6. Fracture Analysis of Rubber Sealing Material for High Pressure Hydrogen Vessel

    National Research Council Canada - National Science Library

    YAMABE, Junichiro; FUJIWARA, Hirotada; NISHIMURA, Shin

    2011-01-01

    In order to clarify the influence of high pressure hydrogen gas on mechanical damage in a rubber O-ring, the fracture analysis of the O-ring used for a sealing material of a pressure hydrogen vessel was conducted...

  7. Analysis of hydrogenated zirconium alloys irradiated with gamma - rays

    Directory of Open Access Journals (Sweden)

    Askhatov Askar

    2017-01-01

    Full Text Available The paper represents the investigations concerning the geometrical size effect of hydrogenated zirconium alloys (Zr-1Ni-H during gamma-ray irradiation on the amount of energy absorbed. The results have shown that the less the cross-sectional dimensions of the sample or product is, the less energy is absorbed. The paper provides theoretical calculations. The zirconium sample with a cross-section of 2.8х2.8 cm absorbs 30-35% of the energy of the incident gamma-ray flow. The increase in the cross-section of a product up to 28 cm leads to the increase in the absorbed energy by more than 2 times. At the same time, the thickness of the product is constant. This effect is explained by the multiple scattering of gamma-rays. It leads to the nonuniform distribution of defects which can accumulate hydrogen and should be considered when developing the analysis methods. These edge effects are confirmed by the measurement of the thermal electromotive force for the samples of zirconium alloys before hydrogenation and gamma-ray irradiation, and after irradiation.

  8. Integrated analysis of hydrogen passenger vehicle transportation pathways

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, C.E.; James, B.D.; Lomax, F.D. Jr.; Kuhn, I.F. Jr. [Directed Technologies, Inc., Arlington, VA (United States)

    1998-08-01

    Hydrogen-powered fuel cell vehicles will reduce local air pollution, greenhouse gas emissions and oil imports. Other alternative vehicles such as gasoline- or methanol-powered fuel cell vehicles, natural gas vehicles and various hybrid electric vehicles with internal combustion engines may also provide significant environmental and national security advantages. This report summarizes a two-year project to compare the direct hydrogen fuel cell vehicle with other alternatives in terms of estimated cost and estimated societal benefits, all relative to a conventional gasoline-powered internal combustion engine vehicle. The cost estimates used in this study involve ground-up, detailed analysis of the major components of a fuel cell vehicle system, assuming mass production in automotive quantities. The authors have also estimated the cost of both gasoline and methanol onboard fuel processors, as well as the cost of stationary hydrogen fueling system components including steam methane reformers, electrolyzers, compressors and stationary storage systems. Sixteen different vehicle types are compared with respect to mass production cost, local air pollution and greenhouse gas emissions.

  9. Mitigation of the hydrogen risk in fusion reactors; Mitigation du risque hydrogene dans les reacteurs de fusion

    Energy Technology Data Exchange (ETDEWEB)

    Maruejouls, C.; Robin, J.C. [CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. d' Etudes des Reacteurs; Arnould, F.; Bachellerie, E. [Technicatome DI SEPS, 13 - Aix en Provence (France); Latge, C. [CEA Cadarache, Dept. d' Etudes des Dechets DED, 13 - Saint Paul lez Durance (France); Laurent, A. [Institut National Polytechnique de Lorraine, Lab. des Sciences du Genie Chimique, 54 - Nancy (France)

    2001-07-01

    The rupture of the first wall and the intrusion of water vapor inside the torus, is one of the major accident that can occur in a thermonuclear fusion reactor. In this situation, water oxidizes the beryllium of the wall and the reaction produces hydrogen with a strong risk of explosion inside the reactor. In order to mitigate this risk, a process based on the reduction of metal oxides (MnO{sub 2}, Ag{sub 2}O) has been developed. The aim of this study is the determination of the kinetics of this reduction reaction. A mixture of both oxides has been deposited on the surface of porous balls for an experiment on fixed beds. The modeling of the phenomenon is based on the equations used in heterogenous catalysis and the experimental determination of the kinetics of the reaction is performed with the CIGNE test-facility. The velocity of the reduction reaction is deduced from the remaining amount of hydrogen in the test-gas (N{sub 2} with 1 to 2% of H{sub 2}) after it has been flowed on the oxides coated balls of the fixed bed. (J.S.)

  10. International Conference on Risk Analysis

    CERN Document Server

    Oliveira, Teresa; Rigas, Alexandros; Gulati, Sneh

    2015-01-01

    This book covers the latest results in the field of risk analysis. Presented topics include probabilistic models in cancer research, models and methods in longevity, epidemiology of cancer risk, engineering reliability and economical risk problems. The contributions of this volume originate from the 5th International Conference on Risk Analysis (ICRA 5). The conference brought together researchers and practitioners working in the field of risk analysis in order to present new theoretical and computational methods with applications in biology, environmental sciences, public health, economics and finance.

  11. Final Report: Hydrogen Production Pathways Cost Analysis (2013 – 2016)

    Energy Technology Data Exchange (ETDEWEB)

    James, Brian David [Strategic Analysis Inc., Arlington, VA (United States); DeSantis, Daniel Allan [Strategic Analysis Inc., Arlington, VA (United States); Saur, Genevieve [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-30

    This report summarizes work conducted under a three year Department of Energy (DOE) funded project to Strategic Analysis, Inc. (SA) to analyze multiple hydrogen (H2) production technologies and project their corresponding levelized production cost of H2. The analysis was conducted using the H2A Hydrogen Analysis Tool developed by the DOE and National Renewable Energy Laboratory (NREL). The project was led by SA but conducted in close collaboration with the NREL and Argonne National Laboratory (ANL). In-depth techno-economic analysis (TEA) of five different H2 production methods was conducted. These TEAs developed projections for capital costs, fuel/feedstock usage, energy usage, indirect capital costs, land usage, labor requirements, and other parameters, for each H2 production pathway, and use the resulting cost and system parameters as inputs into the H2A discounted cash flow model to project the production cost of H2 ($/kgH2). Five technologies were analyzed as part of the project and are summarized in this report: Proton Exchange Membrane technology (PEM), High temperature solid oxide electrolysis cell technology (SOEC), Dark fermentation of biomass for H2 production, H2 production via Monolithic Piston-Type Reactors with rapid swing reforming and regeneration reactions, and Reformer-Electrolyzer-Purifier (REP) technology developed by Fuel Cell Energy, Inc. (FCE).

  12. Techno Economic Analysis of Hydrogen Production by gasification of biomass

    Energy Technology Data Exchange (ETDEWEB)

    Francis Lau

    2002-12-01

    Biomass represents a large potential feedstock resource for environmentally clean processes that produce power or chemicals. It lends itself to both biological and thermal conversion processes and both options are currently being explored. Hydrogen can be produced in a variety of ways. The majority of the hydrogen produced in this country is produced through natural gas reforming and is used as chemical feedstock in refinery operations. In this report we will examine the production of hydrogen by gasification of biomass. Biomass is defined as organic matter that is available on a renewable basis through natural processes or as a by-product of processes that use renewable resources. The majority of biomass is used in combustion processes, in mills that use the renewable resources, to produce electricity for end-use product generation. This report will explore the use of hydrogen as a fuel derived from gasification of three candidate biomass feedstocks: bagasse, switchgrass, and a nutshell mix that consists of 40% almond nutshell, 40% almond prunings, and 20% walnut shell. In this report, an assessment of the technical and economic potential of producing hydrogen from biomass gasification is analyzed. The resource base was assessed to determine a process scale from feedstock costs and availability. Solids handling systems were researched. A GTI proprietary gasifier model was used in combination with a Hysys(reg. sign) design and simulation program to determine the amount of hydrogen that can be produced from each candidate biomass feed. Cost estimations were developed and government programs and incentives were analyzed. Finally, the barriers to the production and commercialization of hydrogen from biomass were determined. The end-use of the hydrogen produced from this system is small PEM fuel cells for automobiles. Pyrolysis of biomass was also considered. Pyrolysis is a reaction in which biomass or coal is partially vaporized by heating. Gasification is a more

  13. Multidimensional Risk Analysis: MRISK

    Science.gov (United States)

    McCollum, Raymond; Brown, Douglas; O'Shea, Sarah Beth; Reith, William; Rabulan, Jennifer; Melrose, Graeme

    2015-01-01

    Multidimensional Risk (MRISK) calculates the combined multidimensional score using Mahalanobis distance. MRISK accounts for covariance between consequence dimensions, which de-conflicts the interdependencies of consequence dimensions, providing a clearer depiction of risks. Additionally, in the event the dimensions are not correlated, Mahalanobis distance reduces to Euclidean distance normalized by the variance and, therefore, represents the most flexible and optimal method to combine dimensions. MRISK is currently being used in NASA's Environmentally Responsible Aviation (ERA) project o assess risk and prioritize scarce resources.

  14. Energy Technology Analysis Prospects for Hydrogen and Fuel Cells

    CERN Document Server

    2005-01-01

    Energy security, economic prosperity and environmental protection are prominent challenges for all countries. The use of hydrogen as an energy carrier and fuel cells as motive devices in transportation and energy distribution systems are possible solutions. This book provides the reader with an authoritative and objective analysis of policy responses and hurdles and business opportunities. Information regarding the latest RD&D, policy initiatives and private sector plans are assessed from the perspective of the rapidly changing global energy system in the next half century. This book prov

  15. Quantitative Risk Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Helms, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-02-10

    The US energy sector is vulnerable to multiple hazards including both natural disasters and malicious attacks from an intelligent adversary. The question that utility owners, operators and regulators face is how to prioritize their investments to mitigate the risks from a hazard that can have the most impact on the asset of interest. In order to be able to understand their risk landscape and develop a prioritized mitigation strategy, they must quantify risk in a consistent way across all hazards their asset is facing. Without being able to quantitatively measure risk, it is not possible to defensibly prioritize security investments or evaluate trade-offs between security and functionality. Development of a methodology that will consistently measure and quantify risk across different hazards is needed.

  16. Nanoparticles: Uncertainty Risk Analysis

    DEFF Research Database (Denmark)

    Grieger, Khara Deanne; Hansen, Steffen Foss; Baun, Anders

    2012-01-01

    Scientific uncertainty plays a major role in assessing the potential environmental risks of nanoparticles. Moreover, there is uncertainty within fundamental data and information regarding the potential environmental and health risks of nanoparticles, hampering risk assessments based on standard...... approaches. To date, there have been a number of different approaches to assess uncertainty of environmental risks in general, and some have also been proposed in the case of nanoparticles and nanomaterials. In recent years, others have also proposed that broader assessments of uncertainty are also needed...... in order to handle the complex potential risks of nanoparticles, including more descriptive characterizations of uncertainty. Some of these approaches are presented and discussed herein, in which the potential strengths and limitations of these approaches are identified along with further challenges...

  17. Risk assessment of vapor cloud explosions in a hydrogen production facility with consequence modeling.

    Science.gov (United States)

    Zarei, Esameil; Jafari, Mohammad Javad; Badri, Naser

    2013-09-17

    New technologies using hazardous materials usually have certain risks. It is more serious when the technology is supposed to be applied in a large scale and become widely used by many people. The objective of this paper was to evaluate the risk of vapor cloud explosion in a hydrogen production process. Potential hazards were identified using the conventional hazard identification method (HAZID). The frequency of the proposed scenarios was estimated from statistical data and existing records. The PHAST professional software was applied for consequence modeling. Both individual and societal risks were evaluated. This cross-sectional study was conducted from June 2010 to December 2011 in a Hydrogen Production Plant in Tehran. The full bore rupture in heat exchanger had the highest harm effect distance. The full bore rupture in desulphurization reactor had the highest (57% of total) individual risk. Full bore rupture in heat exchanger was the highest contributor to social risk. It carried 64% & 66.7% of total risk in day and night respectively. For the sake of safety, mitigation measures should be implemented on heat exchanger, reformer and hydrogen purification absorbers. The main proposed risk reductive measures included; the increasing of installed equipment elevation, the application of smaller vessels and pipes.

  18. Infrared analysis of thin films amorphous, hydrogenated carbon on silicon

    CERN Document Server

    Jacob, W; Schwarz-Selinger, T

    2000-01-01

    The infrared analysis of thin films on a thick substrate is discussed using the example of plasma-deposited, amorphous, hydrogenated carbon layers (a-C:H) on silicon substrates. The framework for the optical analysis of thin films is presented. The main characteristic of thin film optics is the occurrence of interference effects due to the coherent superposition of light multiply reflected at the various internal and external interfaces of the optical system. These interference effects lead to a sinusoidal variation of the transmitted and reflected intensity. As a consequence, the Lambert-Beer law is not applicable for the determination of the absorption coefficient of thin films. Furthermore, observable changes of the transmission and reflection spectra occur in the vicinity of strong absorption bands due to the Kramers-Kronig relation. For a sound data evaluation these effects have to be included in the analysis. To be able to extract the full information contained in a measured optical thin film spectrum, ...

  19. Benchmark exercise on risk assessment methods applied to a virtual hydrogen refuelling station

    NARCIS (Netherlands)

    Ham, K.; Marangon, A.; Middha, P.; Versloot, N.; Rosmuller, N.; Carcassi, M.; Hansen, O.R.; Schiavetti, M.; Papanikolaou, E.; Venetsanos, A.; Engebø, A.; Saw, J.L.; Saffers, J.-B.; Flores, A.; Serbanescu, D.

    2011-01-01

    A benchmarking exercise on quantitative risk assessment (QRA) methodologies for hydrogen safety has been conducted within the project HyQRA, under the framework of the European Network of Excellence (NoE), HySafe. The aim of the exercise was twofold: (i) to identify the differences and similarities

  20. Computer vulnerability risk analysis.

    OpenAIRE

    2008-01-01

    The discussions presented in this dissertation have been undertaken in answer to the need for securing the intellectual assets stored on computer systems. Computer vulnerabilities and their influence on computer systems and the intellectual assets they possess are the main focus of this research. In an effort to portray the influence of vulnerabilities on a computer system, a method for assigning a measure of risk to individual vulnerabilities is proposed. This measure of risk, in turn, gives...

  1. RISK ANALYSIS SERIES. PART ONE - WHY RISK ANALYSIS?

    Directory of Open Access Journals (Sweden)

    Iulian N. BUJOREANU

    2012-01-01

    Full Text Available The goal of this paper is to introduce the reader to the Risk Analysis Series to be developed in the pages of the Journal of Defense Resources Management. Risk analysis is of outmost importance in dealing with resource allocation and this is the reason the paper’s author started this series. Different views and approaches will be added during further discussion about risk analysis so that the reader develops a habit or skills of dealing with this intricate and challenging field.

  2. Hydrogen analysis depth calibration by CORTEO Monte-Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Moser, M., E-mail: marcus.moser@unibw.de [Universität der Bundeswehr München, Institut für Angewandte Physik und Messtechnik LRT2, Fakultät für Luft- und Raumfahrttechnik, 85577 Neubiberg (Germany); Reichart, P.; Bergmaier, A.; Greubel, C. [Universität der Bundeswehr München, Institut für Angewandte Physik und Messtechnik LRT2, Fakultät für Luft- und Raumfahrttechnik, 85577 Neubiberg (Germany); Schiettekatte, F. [Université de Montréal, Département de Physique, Montréal, QC H3C 3J7 (Canada); Dollinger, G., E-mail: guenther.dollinger@unibw.de [Universität der Bundeswehr München, Institut für Angewandte Physik und Messtechnik LRT2, Fakultät für Luft- und Raumfahrttechnik, 85577 Neubiberg (Germany)

    2016-03-15

    Hydrogen imaging with sub-μm lateral resolution and sub-ppm sensitivity has become possible with coincident proton–proton (pp) scattering analysis (Reichart et al., 2004). Depth information is evaluated from the energy sum signal with respect to energy loss of both protons on their path through the sample. In first order, there is no angular dependence due to elastic scattering. In second order, a path length effect due to different energy loss on the paths of the protons causes an angular dependence of the energy sum. Therefore, the energy sum signal has to be de-convoluted depending on the matrix composition, i.e. mainly the atomic number Z, in order to get a depth calibrated hydrogen profile. Although the path effect can be calculated analytically in first order, multiple scattering effects lead to significant deviations in the depth profile. Hence, in our new approach, we use the CORTEO Monte-Carlo code (Schiettekatte, 2008) in order to calculate the depth of a coincidence event depending on the scattering angle. The code takes individual detector geometry into account. In this paper we show, that the code correctly reproduces measured pp-scattering energy spectra with roughness effects considered. With more than 100 μm thick Mylar-sandwich targets (Si, Fe, Ge) we demonstrate the deconvolution of the energy spectra on our current multistrip detector at the microprobe SNAKE at the Munich tandem accelerator lab. As a result, hydrogen profiles can be evaluated with an accuracy in depth of about 1% of the sample thickness.

  3. Campylobacter Risk Analysis

    DEFF Research Database (Denmark)

    Nauta, Maarten

    In several countries quantitative microbiological risk assessments (QMRAs) have been performed for Campylobacter in chicken meat. The models constructed for this purpose provide a good example of the development of QMRA in general and illustrate the diversity of available methods. Despite...... the differences between the models, the most prominent conclusions of the QMRAs are similar. These conclusions for example relate to the large risk of highly contaminated meat products and the insignificance of contamination from Campylobacter positive flocks to negative flocks during slaughter and processing...

  4. VHTR-based Nuclear Hydrogen Plant Analysis for Hydrogen Production with SI, HyS, and HTSE Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Youngjoon; Lee, Taehoon; Lee, Kiyoung; Kim, Minhwan [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In this paper, analyses of material and heat balances on the SI, HyS, and HTSE processes coupled to a Very High Temperature gas-cooled Reactor (VHTR) were performed. The hydrogen production efficiency including the thermal to electric energy ratio demanded from each process is found and the normalized evaluation results obtained from three processes are compared to each other. The currently technological issues to maintain the long term continuous operation of each process will be discussed at the conference site. VHTR-based nuclear hydrogen plant analysis for hydrogen production with SI, HyS, and HTSE facilities has been carried out to determine the thermal efficiency. It is evident that the thermal to electrical energy ratio demanded from each hydrogen production process is an important parameter to select the adequate process for hydrogen production. To improve the hydrogen production efficiency in the SI process coupled to the VHTR without electrical power generation, the demand of electrical energy in the SI process should be minimized by eliminating an electrodialysis step to break through the azeotrope of the HI/I{sub 2}/H{sub 2}O ternary aqueous solution.

  5. Analysis of combined hydrogen, heat, and power as a bridge to a hydrogen transition.

    Energy Technology Data Exchange (ETDEWEB)

    Mahalik, M.; Stephan, C. (Decision and Information Sciences)

    2011-01-18

    Combined hydrogen, heat, and power (CHHP) technology is envisioned as a means to providing heat and electricity, generated on-site, to large end users, such as hospitals, hotels, and distribution centers, while simultaneously producing hydrogen as a by-product. The hydrogen can be stored for later conversion to electricity, used on-site (e.g., in forklifts), or dispensed to hydrogen-powered vehicles. Argonne has developed a complex-adaptive-system model, H2CAS, to simulate how vehicles and infrastructure can evolve in a transition to hydrogen. This study applies the H2CAS model to examine how CHHP technology can be used to aid the transition to hydrogen. It does not attempt to predict the future or provide one forecast of system development. Rather, the purpose of the model is to understand how the system works. The model uses a 50- by 100-mile rectangular grid of 1-square-mile cells centered on the Los Angeles metropolitan area. The major expressways are incorporated into the model, and local streets are considered to be ubiquitous, except where there are natural barriers. The model has two types of agents. Driver agents are characterized by a number of parameters: home and job locations, income, various types of 'personalities' reflective of marketing distinctions (e.g., innovators, early adopters), willingness to spend extra money on 'green' vehicles, etc. At the beginning of the simulations, almost all driver agents own conventional vehicles. They drive around the metropolitan area, commuting to and from work and traveling to various other destinations. As they do so, they observe the presence or absence of facilities selling hydrogen. If they find such facilities conveniently located along their routes, they are motivated to purchase a hydrogen-powered vehicle when it becomes time to replace their present vehicle. Conversely, if they find that they would be inconvenienced by having to purchase hydrogen earlier than necessary or if they

  6. Analysis of the potential for hydrogen production in the province of Cordoba, Argentina, from wind resources

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, C.R.; Santa Cruz, R.; Aisa, S. [Universidad Empresarial Siglo 21, Monsenor Pablo Cabrera s/n calle, 5000 Cordoba (Argentina); Riso, M.; Jimenez Yob, G.; Ottogalli, R. [Subsecretaria de Infraestructuras y Programas, Ministerio de Obras y Servicios Publicos del Gobierno de la Provincia de Cordoba, Av. Poeta Lugones 12, 2do. Piso, 5000 Cordoba (Argentina); Jeandrevin, G. [Instituto Universitario Aeronautico, Avenida Fuerza Aerea km 6 1/2, 5022 Cordoba (Argentina); Leiva, E.P.M. [INFIQC, Unidad de Matematica y Fisica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Haya de la Torre s/n, 5010 Cordoba (Argentina)

    2010-06-15

    The potential for hydrogen production from wind resources in the province of Cordoba, second consumer of fossil fuels for transportation in Argentina, is analyzed. Three aspects of the problem are considered: the evaluation of the hydrogen resource from wind power, the analysis of the production costs via electrolysis and the annual requirements of wind energy to generate hydrogen to fuel the vehicular transport of the province. Different scenarios were considered, including pure hydrogen as well as the so-called CNG plus, where hydrogen is mixed with compressed natural gas in a 20% V/V dilution of the former. The potential for hydrogen production from wind resources is analyzed for each department of the province, excluding those regions not suited for wind farms. The analysis takes into account the efficiency of the electrolyzer and the capacity factor of the wind power system. It is concluded that the automotive transportation could be supplied by hydrogen stemming from wind resources via electrolysis. (author)

  7. Overview on hydrogen risk research and development activities: Methodology and open issues

    Directory of Open Access Journals (Sweden)

    Ahmed Bentaib

    2015-02-01

    Full Text Available During the course of a severe accident in a light water nuclear reactor, large amounts of hydrogen can be generated and released into the containment during reactor core degradation. Additional burnable gases [hydrogen (H2 and carbon monoxide (CO] may be released into the containment in the corium/concrete interaction. This could subsequently raise a combustion hazard. As the Fukushima accidents revealed, hydrogen combustion can cause high pressure spikes that could challenge the reactor buildings and lead to failure of the surrounding buildings. To prevent the gas explosion hazard, most mitigation strategies adopted by European countries are based on the implementation of passive autocatalytic recombiners (PARs. Studies of representative accident sequences indicate that, despite the installation of PARs, it is difficult to prevent at all times and locations, the formation of a combustible mixture that potentially leads to local flame acceleration. Complementary research and development (R&D projects were recently launched to understand better the phenomena associated with the combustion hazard and to address the issues highlighted after the Fukushima Daiichi events such as explosion hazard in the venting system and the potential flammable mixture migration into spaces beyond the primary containment. The expected results will be used to improve the modeling tools and methodology for hydrogen risk assessment and severe accident management guidelines. The present paper aims to present the methodology adopted by Institut de Radioprotection et de Sûreté Nucléaire to assess hydrogen risk in nuclear power plants, in particular French nuclear power plants, the open issues, and the ongoing R&D programs related to hydrogen distribution, mitigation, and combustion.

  8. Hydrogen and Biofuels - A Modeling Analysis of Competing Energy Carriers for Western Europe

    Energy Technology Data Exchange (ETDEWEB)

    Guel, Timur; Kypreos, Socrates; Barreto, Leonardo

    2007-07-01

    This paper deals with the prospects of hydrogen and biofuels as energy carriers in the Western European transportation sector. The assessment is done by combining the US hydrogen analysis H2A models for the design of hydrogen production and delivery chains, and the Western European Hydrogen Markal Model EHM with a detailed representation of biofuels, and the European electricity and transportation sector. The paper derives policy recommendations to support the market penetration of hydrogen and biofuels, and investigates learning interactions between the different energy carriers. (auth)

  9. Theoretical analysis of hydrogen spillover mechanism on carbon nanotubes

    National Research Council Canada - National Science Library

    Juarez-Mosqueda, Rosalba; Mavrandonakis, Andreas; Kuc, Agnieszka B; Pettersson, Lars G M; Heine, Thomas

    2015-01-01

    The spillover mechanism of molecular hydrogen on carbon nanotubes in the presence of catalytically active platinum clusters was critically and systematically investigated by using density-functional theory...

  10. Hydrogenated fullerenes in space: FT-IR spectra analysis

    Energy Technology Data Exchange (ETDEWEB)

    El-Barbary, A. A. [Physics Department, Faculty of Education, Ain-Shams University, Cairo, Egypt Physics Department, Faculty of Science, Jazan University, Jazan (Saudi Arabia)

    2016-06-10

    Fullerenes and hydrogenated fullerenes are found in circumstellar and interstellar environments. But the determination structures for the detected bands in the interstellar and circumstellar space are not completely understood so far. For that purpose, the aim of this article is to provide all possible infrared spectra for C{sub 20} and C{sub 60} fullerenes and their hydrogenated fullerenes. Density Functional theory (DFT) is applied using B3LYP exchange-functional with basis set 6–31G(d, p). The Fourier transform infrared spectroscopy (FT-IR) is found to be capable of distinguishing between fullerenes, mono hydrogenated fullerenes and fully hydrogenated fullerenes. In addition, deposition of one hydrogen atom outside the fully hydrogenated fullerenes is found to be distinguished by forming H{sub 2} molecule at peak around 4440 cm{sup −1}. However, deposition of one hydrogen atom inside the fully hydrogenated fullerenes cannot be distinguished. The obtained spectral structures are analyzed and are compared with available experimental results.

  11. Technical analysis of photovoltaic/wind systems with hydrogen storage

    Directory of Open Access Journals (Sweden)

    Bakić Vukman V.

    2012-01-01

    Full Text Available The technical analysis of a hybrid wind-photovoltaic energy system with hydrogen gas storage was studied. The market for the distributed power generation based on renewable energy is increasing, particularly for the standalone mini-grid applications. The main design components of PV/Wind hybrid system are the PV panels, the wind turbine and an alkaline electrolyzer with tank. The technical analysis is based on the transient system simulation program TRNSYS 16. The study is realized using the meteorological data for a Typical Metrological Year (TMY for region of Novi Sad, Belgrade cities and Kopaonik national park in Serbia. The purpose of the study is to design a realistic energy system that maximizes the use of renewable energy and minimizes the use of fossil fuels. The reduction in the CO2 emissions is also analyzed in the paper. [Acknowledgment. This paper is the result of the investigations carried out within the scientific project TR33036 supported by the Ministry of Science of the Republic of Serbia.

  12. Hydrogen engine performance analysis project. Second annual report

    Energy Technology Data Exchange (ETDEWEB)

    Adt, Jr., R. R.; Swain, M. R.; Pappas, J. M.

    1980-01-01

    Progress in a 3 year research program to evaluate the performance and emission characteristics of hydrogen-fueled internal combustion engines is reported. Fifteen hydrogen engine configurations will be subjected to performance and emissions characterization tests. During the first two years, baseline data for throttled and unthrottled, carburetted and timed hydrogen induction, Pre IVC hydrogen-fueled engine configurations, with and without exhaust gas recirculation (EGR) and water injection, were obtained. These data, along with descriptions of the test engine and its components, the test apparatus, experimental techniques, experiments performed and the results obtained, are given. Analyses of other hydrogen-engine project data are also presented and compared with the results of the present effort. The unthrottled engine vis-a-vis the throttled engine is found, in general, to exhibit higher brake thermal efficiency. The unthrottled engine also yields lower NO/sub x/ emissions, which were found to be a strong function of fuel-air equivalence ratio. (LCL)

  13. Overview on hydrogen risk research and development activities: Methodology and open issues

    Energy Technology Data Exchange (ETDEWEB)

    Bentaib, Ahmed; Meynet, Nicolas; Bleyer, Alexande [Institut de Radioprotection et de Surete Nucleaire (IRSN), Severe Accident Department, Fontenay-aux-Roses (France)

    2015-02-15

    During the course of a severe accident in a light water nuclear reactor, large amounts of hydrogen can be generated and released into the containment during reactor core degradation. Additional burnable gases [hydrogen (H2) and carbon monoxide (CO)] may be released into the containment in the corium/concrete interaction. This could subsequently raise a combustion hazard. As the Fukushima accidents revealed, hydrogen combustion can cause high pressure spikes that could challenge the reactor buildings and lead to failure of the surrounding buildings. To prevent the gas explosion hazard, most mitigation strategies adopted by European countries are based on the implementation of passive autocatalytic recombiners (PARs). Studies of representative accident sequences indicate that, despite the installation of PARs, it is difficult to prevent at all times and locations, the formation of a combustible mixture that potentially leads to local flame acceleration. Complementary research and development (R and D) projects were recently launched to understand better the phenomena associated with the combustion hazard and to address the issues highlighted after the Fukushima Daiichi events such as explosion hazard in the venting system and the potential flammable mixture migration into spaces beyond the primary containment. The expected results will be used to improve the modeling tools and methodology for hydrogen risk assessment and severe accident management guidelines. The present paper aims to present the methodology adopted by Institut de Radioprotection et de Su.

  14. The Assessment of Hydrogen Energy Systems for Fuel Cell Vehicles Using Principal Component Analysis and Cluster Analysis

    OpenAIRE

    Ren, Jing-Zheng; Tan, Shi-yu; Dong, Li-chun

    2012-01-01

    Hydrogen energy which has been recognized as an alternative instead of fossil fuel has been developed rapidly in fuel cell vehicles. Different hydrogen energy systems have different performances on environmental, economic, and energy aspects. A methodology for the quantitative evaluation and analysis of the hydrogen systems is meaningful for decision makers to select the best scenario. principal component analysis (PCA) has been used to evaluate the integrated performance of different hydroge...

  15. Technoeconomic analysis of renewable hydrogen production, storage, and detection systems

    Energy Technology Data Exchange (ETDEWEB)

    Mann, M.K.; Spath, P.L.; Kadam, K. [National Renewable Energy Lab., Golden, CO (United States)

    1996-10-01

    Technical and economic feasibility studies of different degrees of completeness and detail have been performed on several projects being funded by the Department of Energy`s Hydrogen Program. Work this year focused on projects at the National Renewable Energy Laboratory, although analyses of projects at other institutions are underway or planned. Highly detailed analyses were completed on a fiber optic hydrogen leak detector and a process to produce hydrogen from biomass via pyrolysis followed by steam reforming of the pyrolysis oil. Less detailed economic assessments of solar and biologically-based hydrogen production processes have been performed and focused on the steps that need to be taken to improve the competitive position of these technologies. Sensitivity analyses were conducted on all analyses to reveal the degree to which the cost results are affected by market changes and technological advances. For hydrogen storage by carbon nanotubes, a survey of the competing storage technologies was made in order to set a baseline for cost goals. A determination of the likelihood of commercialization was made for nearly all systems examined. Hydrogen from biomass via pyrolysis and steam reforming was found to have significant economic potential if a coproduct option could be co-commercialized. Photoelectrochemical hydrogen production may have economic potential, but only if low-cost cells can be modified to split water and to avoid surface oxidation. The use of bacteria to convert the carbon monoxide in biomass syngas to hydrogen was found to be slightly more expensive than the high end of currently commercial hydrogen, although there are significant opportunities to reduce costs. Finally, the cost of installing a fiber-optic chemochromic hydrogen detection system in passenger vehicles was found to be very low and competitive with alternative sensor systems.

  16. U.S. Geographic Analysis of the Cost of Hydrogen from Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Saur, G.; Ainscough, C.

    2011-12-01

    This report summarizes U.S. geographic analysis of the cost of hydrogen from electrolysis. Wind-based water electrolysis represents a viable path to renewably-produced hydrogen production. It might be used for hydrogen-based transportation fuels, energy storage to augment electricity grid services, or as a supplement for other industrial hydrogen uses. This analysis focuses on the levelized production, costs of producing green hydrogen, rather than market prices which would require more extensive knowledge of an hourly or daily hydrogen market. However, the costs of hydrogen presented here do include a small profit from an internal rate of return on the system. The cost of renewable wind-based hydrogen production is very sensitive to the cost of the wind electricity. Using differently priced grid electricity to supplement the system had only a small effect on the cost of hydrogen; because wind electricity was always used either directly or indirectly to fully generate the hydrogen. Wind classes 3-6 across the U.S. were examined and the costs of hydrogen ranged from $3.74kg to $5.86/kg. These costs do not quite meet the 2015 DOE targets for central or distributed hydrogen production ($3.10/kg and $3.70/kg, respectively), so more work is needed on reducing the cost of wind electricity and the electrolyzers. If the PTC and ITC are claimed, however, many of the sites will meet both targets. For a subset of distributed refueling stations where there is also inexpensive, open space nearby this could be an alternative to central hydrogen production and distribution.

  17. HBonanza: a computer algorithm for molecular-dynamics-trajectory hydrogen-bond analysis.

    Science.gov (United States)

    Durrant, Jacob D; McCammon, J Andrew

    2011-11-01

    In the current work, we present a hydrogen-bond analysis of 2673 ligand-receptor complexes that suggests the total number of hydrogen bonds formed between a ligand and its receptor is a poor predictor of ligand potency; furthermore, even that poor prediction does not suggest a statistically significant correlation between hydrogen-bond formation and potency. While we are not the first to suggest that hydrogen bonds on average do not generally contribute to ligand binding affinities, this additional evidence is nevertheless interesting. The primary role of hydrogen bonds may instead be to ensure specificity, to correctly position the ligand within the active site, and to hold the protein active site in a ligand-friendly conformation. We also present a new computer program called HBonanza (hydrogen-bond analyzer) that aids the analysis and visualization of hydrogen-bond networks. HBonanza, which can be used to analyze single structures or the many structures of a molecular dynamics trajectory, is open source and python implemented, making it easily editable, customizable, and platform independent. Unlike many other freely available hydrogen-bond analysis tools, HBonanza provides not only a text-based table describing the hydrogen-bond network, but also a Tcl script to facilitate visualization in VMD, a popular molecular visualization program. Visualization in other programs is also possible. A copy of HBonanza can be obtained free of charge from http://www.nbcr.net/hbonanza. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Initial Decision and Risk Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Engel, David W.

    2012-02-29

    Decision and Risk Analysis capabilities will be developed for industry consideration and possible adoption within Year 1. These tools will provide a methodology for merging qualitative ranking of technology maturity and acknowledged risk contributors with quantitative metrics that drive investment decision processes. Methods and tools will be initially introduced as applications to the A650.1 case study, but modular spreadsheets and analysis routines will be offered to industry collaborators as soon as possible to stimulate user feedback and co-development opportunities.

  19. Theoretical analysis of hydrogen spillover mechanism on carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Rosalba eJuarez Mosqueda

    2015-02-01

    Full Text Available The spillover mechanism of molecular hydrogen on carbon nanotubes in the presence of catalytically active platinum clusters was critically and systematically investigated by using density-functional theory. Our simulation model includes a Pt4 cluster for the catalyst nanoparticle and curved and planar circumcoronene for two exemplary single-walled carbon nanotubes (CNT, the (10,10 CNT and one of large diameter, respectively. Our results show that the H2 molecule dissociates spontaneously on the Pt4 cluster. However, the dissociated H atoms have to overcome a barrier of more than 2 eV to migrate from the catalyst to the CNT, even if the Pt4 cluster is at full saturation with six adsorbed and dissociated hydrogen molecules. Previous investigations have shown that the mobility of hydrogen atoms on the CNT surface is hindered by a barrier. We find that instead the Pt4 catalyst may move along the outer surface of the CNT with activation energy of only 0.16 eV, and that this effect offers the possibility of full hydrogenation of the CNT. Thus, although we have not found a low-energy pathway to spillover onto the CNT, we suggest, based on our calculations and calculated data reported in the literature, that in the hydrogen-spillover process the observed saturation of the CNT at hydrogen background pressure occurs through mobile Pt nanoclusters, which move on the substrate more easily than the substrate-chemisorbed hydrogens, and deposit or reattach hydrogens in the process. Initial hydrogenation of the carbon substrate, however, is thermodynamically unfavoured, suggesting that defects should play a significant role.

  20. Heat Analysis of Liquid piston Compressor for Hydrogen Applications

    DEFF Research Database (Denmark)

    Kermani, Nasrin Arjomand; Rokni, Masoud

    2014-01-01

    is developed based on the mass and energy balance of the hydrogen, liquid and the wall of the compression chamber at each time step and positional node with various compression ratios to calculate the temperature distribution of the system. The amount of heat extracted from hydrogen, directly at the interface......A new hydrogen compression technology using liquid as the compression piston is investigated from heat transfer point of view. A thermodynamic model, simulating a single compression stroke, is developed to investigate the heat transfer phenomena inside the compression chamber. The model...

  1. Hydrogen Fueling Station in Honolulu, Hawaii Feasibility Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Porter Hill; Michael Penev

    2014-08-01

    The Department of Energy Hydrogen & Fuel Cells Program Plan (September 2011) identifies the use of hydrogen for government and fleet electric vehicles as a key step for achieving “reduced greenhouse gas emissions; reduced oil consumption; expanded use of renewable power …; highly efficient energy conversion; fuel flexibility …; reduced air pollution; and highly reliable grid-support.” This report synthesizes several pieces of existing information that can inform a decision regarding the viability of deploying a hydrogen (H2) fueling station at the Fort Armstrong site in Honolulu, Hawaii.

  2. Analysis of hydrogen operation in the Danish Traffic System

    DEFF Research Database (Denmark)

    Jørgensen, Kaj

    1996-01-01

    The main report of a study of the utilisation of hydrogen in the Danish energy and traffic system.The report contains an overview and assessment of the potential hydrogen technologies as well as analyses of the energy and environmental effects of different applications in the Danish transport sec...... sector (passenger car, bus, van, truck). The report concludes that hydrogen along with electric and hybrid propulsion can be a very interesting element in a strategy for sustainable transport, but only if based mainly on renewable energy....

  3. Reliability of symptom analysis during carbohydrate hydrogen-breath tests.

    Science.gov (United States)

    Fernández-Bañares, Fernando

    2012-09-01

    Relevance of symptom analysis during hydrogen breath test (HBT) for establishing a clinical diagnosis of sugar intolerance is reviewed. Evaluation of symptoms developed in response to the ingestion of 50 g lactose could represent a simple screening test to select patients for lactose intolerance testing. Patients who do not develop symptoms do not need to be referred for HBT. In addition, symptoms reported by patients during a negative HBT cannot be at all times attributed to a false-negative test; instead, a 'nocebo' effect is likely to be implicated. On the other hand, in a double-blind randomized study, a dose of 25 g fructose was suggested as the most appropriate for testing individuals with suspected fructose malabsorption, whereas symptom reliability to diagnose fructose intolerance was inaccurate. Whereas the development of symptoms after a positive HBT may indicate sugar intolerance, it is still not clear whether the absence of symptoms after sugar malabsorption gives any indication as to the role of that sugar in the genesis of patient's complaints. Further studies should evaluate whether the disappearance of symptoms with a sugar-restricted diet after a positive HBT is a better diagnostic criterion of sugar intolerance than the development of symptoms.

  4. Qualitative and quantitative analysis of solar hydrogen generation literature from 2001 to 2014.

    Science.gov (United States)

    Maghami, Mohammad Reza; Asl, Shahin Navabi; Rezadad, Mohammad Esmaeil; Ale Ebrahim, Nader; Gomes, Chandima

    Solar hydrogen generation is one of the new topics in the field of renewable energy. Recently, the rate of investigation about hydrogen generation is growing dramatically in many countries. Many studies have been done about hydrogen generation from natural resources such as wind, solar, coal etc. In this work we evaluated global scientific production of solar hydrogen generation papers from 2001 to 2014 in any journal of all the subject categories of the Science Citation Index compiled by Institute for Scientific Information (ISI), Philadelphia, USA. Solar hydrogen generation was used as keywords to search the parts of titles, abstracts, or keywords. The published output analysis showed that hydrogen generation from the sun research steadily increased over the past 14 years and the annual paper production in 2013 was about three times 2010-paper production. The number of papers considered in this research is 141 which have been published from 2001 to this date. There are clear distinctions among author keywords used in publications from the five most high-publishing countries such as USA, China, Australia, Germany and India in solar hydrogen studies. In order to evaluate this work quantitative and qualitative analysis methods were used to the development of global scientific production in a specific research field. The analytical results eventually provide several key findings and consider the overview hydrogen production according to the solar hydrogen generation.

  5. Technoeconomic analysis of different options for the production of hydrogen from sunlight, wind, and biomass

    Energy Technology Data Exchange (ETDEWEB)

    Mann, M.K.; Spath, P.L.; Amos, W.A. [National Renewable Energy Lab., Golden, CO (United States)

    1998-08-01

    To determine their technical and economic viability and to provide insight into where each technology is in its development cycle, different options to produce hydrogen from sunlight, wind, and biomass were studied. Additionally, costs for storing and transporting hydrogen were determined for different hydrogen quantities and storage times. The analysis of hydrogen from sunlight examined the selling price of hydrogen from two technologies: direct photoelectrochemical (PEC) conversion of sunlight and photovoltaic (PV)-generated electricity production followed by electrolysis. The wind analysis was based on wind-generated electricity production followed by electrolysis. In addition to the base case analyses, which assume that hydrogen is the sole product, three alternative scenarios explore the economic impact of integrating the PV- and wind-based systems with the electric utility grid. Results show that PEC hydrogen production has the potential to be economically feasible. Additionally, the economics of the PV and wind electrolysis systems are improved by interaction with the grid. The analysis of hydrogen from biomass focused on three gasification technologies. The systems are: low pressure, indirectly-heated gasification followed by steam reforming; high pressure, oxygen-blown gasification followed by steam reforming; and pyrolysis followed by partial oxidation. For each of the systems studied, the downstream process steps include shift conversion followed by hydrogen purification. Only the low pressure system produces hydrogen within the range of the current industry selling prices (typically $0.7--$2/kg, or $5--14/GJ on a HHV basis). A sensitivity analysis showed that, for the other two systems, in order to bring the hydrogen selling price down to $2/kg, negative-priced feedstocks would be required.

  6. How resonance assists hydrogen bonding interactions: an energy decomposition analysis.

    Science.gov (United States)

    Beck, John Frederick; Mo, Yirong

    2007-01-15

    Block-localized wave function (BLW) method, which is a variant of the ab initio valence bond (VB) theory, was employed to explore the nature of resonance-assisted hydrogen bonds (RAHBs) and to investigate the mechanism of synergistic interplay between pi delocalization and hydrogen-bonding interactions. We examined the dimers of formic acid, formamide, 4-pyrimidinone, 2-pyridinone, 2-hydroxpyridine, and 2-hydroxycyclopenta-2,4-dien-1-one. In addition, we studied the interactions in beta-diketone enols with a simplified model, namely the hydrogen bonds of 3-hydroxypropenal with both ethenol and formaldehyde. The intermolecular interaction energies, either with or without the involvement of pi resonance, were decomposed into the Hitler-London energy (DeltaEHL), polarization energy (DeltaEpol), charge transfer energy (DeltaECT), and electron correlation energy (DeltaEcor) terms. This allows for the examination of the character of hydrogen bonds and the impact of pi conjugation on hydrogen bonding interactions. Although it has been proposed that resonance-assisted hydrogen bonds are accompanied with an increasing of covalency character, our analyses showed that the enhanced interactions mostly originate from the classical dipole-dipole (i.e., electrostatic) attraction, as resonance redistributes the electron density and increases the dipole moments in monomers. The covalency of hydrogen bonds, however, changes very little. This disputes the belief that RAHB is primarily covalent in nature. Accordingly, we recommend the term "resonance-assisted binding (RAB)" instead of "resonance-assisted hydrogen bonding (RHAB)" to highlight the electrostatic, which is a long-range effect, rather than the electron transfer nature of the enhanced stabilization in RAHBs. Copyright (c) 2006 Wiley Periodicals, Inc.

  7. Performance Analysis of Hybrid Solar-Hydrogen Energy System

    Science.gov (United States)

    Xiao, Jinsheng; Guan, Xuehua

    The system of solar thermoelectric-photovoltaic hybrid generation for hydrogen production is designed in this paper. The mathematical model of the hybrid system using MATLAB/SIMULINK software is carried out. And the logic control system is designed. The current of the various sub-systems and the energy of the hydrogen storage tank are simulated and analyzed, this paper proves the solar hybrid system can be reliable and effective.

  8. Expanded Capabilities for the Hydrogen Financial Analysis Scenario Tool (H2FAST)

    Energy Technology Data Exchange (ETDEWEB)

    Bush, Brian; Melaina, Marc; Penev, Michael

    2016-06-08

    This presentation describes how NREL expanded the capabilities for the Hydrogen Financial Analysis Scenario Tool (H2FAST) in FY16. It was presented at the U.S. Department of Energy Hydrogen and Fuel Cells Program 2016 Annual Merit Review and Peer Evaluation Meeting on June 8, 2016, in Washington, D.C.

  9. Engineering analysis of potential photosynthetic bacterial hydrogen-production systems

    Science.gov (United States)

    Herlevich, A.; Karpuk, M. E.

    1982-06-01

    Photosynthetic bacteria (PSB) are capable of generating hydrogen from organics in effluents from food processing, pulp and paper, and chemical and pharmaceutical industries. Hydrogen evolution takes place under light in the absence of air. The rate of hydrogen production is expected to range between 300 to 600 scf of hydrogen per 1000 galloons of waste stream treated per hour. This hydrogen production system has been demonstrated at a bench-scale level and is ready for engineering development. A conceptual design for a PSB hydrogen production system is described. The system is expected to be sited adjacent to a waste stream source which will be pretreated by fermentation and pH adjustment, innoculated with bacteria, and then passed into the reactor. The reactor effluent can either be discharged into a rapid infiltration system, an irrigation ditch, and/or recycled back into the reactor. Several potential reactor designs have been developed, analyzed, and costed. A large covered pond appears to be the most economical design approach.

  10. Risk Analysis in Road Tunnels – Most Important Risk Indicators

    DEFF Research Database (Denmark)

    Berchtold, Florian; Knaust, Christian; Thöns, Sebastian

    2016-01-01

    Methodologies on fire risk analysis in road tunnels consider numerous factors affecting risks (risk indicators) and express the results by risk measures. But only few comprehensive studies on effects of risk indicators on risk measures are available. For this reason, this study quantifies...... the effects and highlights the most important risk indicators with the aim to support further developments in risk analysis. Therefore, a system model of a road tunnel was developed to determine the risk measures. The system model can be divided into three parts: the fire part connected to the fire model Fire...

  11. Conceptual risk assessment framework for global change risk analysis SRP

    CSIR Research Space (South Africa)

    Elphinstone, CD

    2007-12-01

    Full Text Available This report is submitted as a deliverable of the SRP project Global Change Risk Analysis which aims at applying risk analysis as a unifying notion for quantifying and communicating threats to ecosystem services originating from global change...

  12. U.S. Clean Energy Hydrogen and Fuel Cell Technologies: A Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fullenkamp, Patrick [Westside Industrial Retention & Expansion Network, Cleveland, OH (United States); Holody, Diane [Westside Industrial Retention & Expansion Network, Cleveland, OH (United States); James, Brian [Strategic Analysis, Inc., Arlington, VA (United States); Houchins, Cassidy [Strategic Analysis, Inc., Arlington, VA (United States); Wheeler, Douglas [DJW Technology, Dublin, OH (United States); Hart, David [E4tech, London (United Kingdom); Lehner, Franz [E4tech, London (United Kingdom)

    2017-10-10

    The objectives of this project are a 1) Global Competitiveness Analysis of hydrogen and fuel cell systems and components manufactured including 700 bar compressed hydrogen storage system in the U.S., Europe, Asia, and other key areas to be identified to determine the global cost leaders, the best current manufacturing processes, the key factors determining competitiveness, and the potential means of cost reductions; and an 2) Analysis to assess the status of global hydrogen and fuel cell markets. The analysis of units, megawatts by country and by application will focus on polymer electrolyte membrane (PEM) fuel cell systems (automotive and stationary).

  13. Detailed kinetic modeling and sensitivity analysis of hydrogen iodide decomposition in sulfur-iodine cycle for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanwei; Zhou, Junhu; Wang, Zhihua; Cen, Kefa [State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027 (China)

    2008-01-15

    A new detailed kinetic modeling was developed for homogeneous decomposition of hydrogen iodide (HI) in the sulfur-iodine cycle. Results show the HI decomposition reaction is sensitive to temperature, and the response time of reaction reduces from 1 s to 10 ms as temperature increases from 500 to 800 {sup circle} C. The decomposition is also improved as pressure increased. Kinetic calculations are also compared with the experimental data, and all trends of the experiment can be reproduced by the model. Sensitivity analysis shows that the reactions of HI with HI, H and I play a major role in the hydrogen production process and the hydrogen consumption occurs primarily by reaction of H with I{sub 2} and reaction of I with H{sub 2} to form HI. As temperature increases, different reactions play a dominant role in HI decomposition process. Based on the detailed kinetic modeling and sensitivity analysis results, the HI decomposition reaction path diagram was constructed in this paper. (author)

  14. Breath hydrogen analysis in patients with ileoanal pouch anastomosis

    DEFF Research Database (Denmark)

    Bruun, E; Meyer, J N; Rumessen, J J

    1995-01-01

    The possible influence on functional outcomes of hydrogen production in the ileoanal pouch after restorative proctocolectomy was investigated by means of lactulose H2 breath tests. Eight of 15 patients had significant increases in breath hydrogen after 10 g lactulose. One patient declined...... to participate in further investigations, the remaining seven responders had no evidence of small bowel bacterial overgrowth after glucose H2 breath tests. The ability to produce hydrogen by anaerobic fermentation of lactulose in the pouch was unrelated to the age of the patients or of the pouch. Seven of eight...... responders had successive breath tests after ingestion of lactulose 20 g and wheat starch 100 g. Five of seven had significant increases after lactulose but none after wheat starch. The overall function of the pouch continence, spontaneity of defecation, and 24 hour stool frequency was significantly better...

  15. Thermodynamic analysis of hydrogen production via hydrothermal gasification of hexadecane

    KAUST Repository

    Alshammari, Yousef M.

    2012-04-01

    This work reports the equilibrium behaviour of the hydrothermal gasification of hexadecane, a heavy saturate model compound, under non-oxidative isothermal and oxidative adiabatic conditions, using the Peng-Robinson equation of state and the direct minimisation of Gibbs free energy employed within the Aspen HYSYS. This modelling enabled establishing both the limits and optimum conditions at which the hydrogen molar yield may be theoretically maximised. The effects of parameters including the reactor isothermal temperature, pressure, water to carbon ratio, and oxygen to carbon ratio on the molar yields of produced gaseous species were analysed. The model has been validated by comparing its results with different reported modelling and experimental data under identical conditions which resulted in a good agreement. The results reported in this work show the potential of achieving economic yields of hydrogen and syngas from liquid hydrocarbons under downhole hydrothermal conditions. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights.

  16. Hydrogen production employing Spirulina maxima 2342: A chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Juantorena, A.U.; Santoyo, E.; Gamboa, S.A.; Lastres, O.D. [Centro de Investigacion en Energia, UNAM, Temixco 62580, Morelos (Mexico); Sebastian, P.J. [Centro de Investigacion en Energia, UNAM, Temixco 62580, Morelos (Mexico); Cuerpo Academico de Energia, UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico); Sanchez-Escamilla, D. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Bustos, A. [Centro de Ciencias Fisicas, UNAM, Ave. Universidad, Cuernavaca, Morelos (Mexico); Eapen, D. [Investigacion y Desarrollo en Agroindustria, UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico)

    2007-10-15

    The biomass of the cyanobacteria, Spirulina maxima 2342, was autotrophically obtained in a 20 l bioreactor under illumination and air bubbling and analyzed for its photobiological hydrogen production capability. A volume of 250 ml of Spirulina sp. taken from the reactor was used as culture sample for performing the experiments. An illumination-agitation process was employed to induce the hydrogen photoproduction reaction. The hydrogen produced in this process was quantified by gas chromatography technique using Molesieve 5 A(16ft x (1)/(8)in) column and a thermal conductivity detector (with a detector temperature of 110{sup o}C and a column temperature of 60{sup o}C). The culture samples were finally observed in an electron microscope to evaluate the effect of vacuum on the Spirulina sp. cells. (author)

  17. RISK ANALYSIS IN MEAT PRODUCING

    Directory of Open Access Journals (Sweden)

    I. PIRVUTOIU

    2008-05-01

    Full Text Available This paper aimed to evaluate Risk bankruptcy using “Score Method” based on Canon and Holder’s Model. The data were collected from the Balance Sheet and Profit and Loss Account for the period 2005-2007, recorded by a Dairy Farm . The study has put in evidence the bad financial situation of the company a reason to face a high risk bankruptcy in the all the three years. The high values of Z score function recorded every year reflects that there is no room for a financial recover, as long as the risk coefficient is higher than 80 %. Such a risk analysis would have to be made a few years ago in order to be useful for identifying in time the factors with a negative influence on the financial statement and to take the corresponding measures for avoiding such a bankruptcy. For Dairy commercial farms, such an analysis is compulsory at present taking into account the risky business environment.

  18. Technical Analysis of the Hydrogen Energy Station Concept, Phase I and Phase II

    Energy Technology Data Exchange (ETDEWEB)

    TIAX, LLC

    2005-05-04

    patterns would be most viable for an energy station, TIAX developed several criteria for selecting a representative set of technology configurations. TIAX applied these criteria to all possible technology configurations to determine an optimized set for further analysis, as shown in Table ES-1. This analysis also considered potential energy station operational scenarios and their impact upon hydrogen and power production. For example, an energy station with a 50-kWe reformer could generate enough hydrogen to serve up to 12 vehicles/day (at 5 kg/fill) or generate up to 1,200 kWh/day, as shown in Figure ES-1. Buildings that would be well suited for an energy station would utilize both the thermal and electrical output of the station. Optimizing the generation and utilization of thermal energy, hydrogen, and electricity requires a detailed look at the energy transfer within the energy station and the transfer between the station and nearby facilities. TIAX selected the Baseline configuration given in Table ES-1 for an initial analysis of the energy and mass transfer expected from an operating energy station. Phase II The purpose of this technical analysis was to analyze the development of a hydrogen-dispensing infrastructure for transportation applications through the installation of a 50-75 kW stationary fuel cell-based energy station at federal building sites. The various scenarios, costs, designs and impacts of such a station were quantified for a hypothetical cost-shared program that utilizes a natural gas reformer to provide hydrogen fuel for both the stack(s) and a limited number of fuel cell powered vehicles, with the possibility of using cogeneration to support the building heat load.

  19. Metabolic flux analysis of the hydrogen production potential in Synechocystis sp. PCC6803

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, E. [Departamento de Lenguajes y Ciencias de la Computacion, Campus de Teatrinos, Universidad de Malaga, 29071 Malaga (Spain); Montagud, A.; Fernandez de Cordoba, P.; Urchueguia, J.F. [Instituto Universitario de Matematica Pura y Aplicada, Universidad Politecnica de Valencia, Camino de Vera 14, 46022 Valencia (Spain)

    2009-11-15

    Hydrogen is a promising energy vector; however, finding methods to produce it from renewable sources is essential to allow its wide-scale use. In that line, biological hydrogen production, although it is considered as a possible alternative, requires substantial improvements to overcome its present low yields. In that direction, genetic manipulation probably will play a central role and from that point of view metabolic flux analysis (MFA) constitutes an important tool to guide a priori most suitable genetic modifications oriented to a hydrogen yield increase. In this work MFA has been applied to analyze hydrogen photoproduction of Synechocystis sp. PCC6803. Flux analysis was carried out based on literature data and several basic fluxes were estimated in different growing conditions of the system. From this analysis, an upper limit for hydrogen photoproduction has been determined indicating a wide margin for improvement. MFA was also used to find a feasible operating space for hydrogen production, which avoids oxygen inhibition, one of the most important limitations to make hydrogen production cost effective. In addition, a set of biotechnological strategies are proposed that would be consistent with the performed mathematical analysis. (author)

  20. Lifecycle Cost Analysis of Hydrogen Versus Other Technologies for Electrical Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Steward, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Saur, G. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Penev, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ramsden, T. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2009-11-01

    This report presents the results of an analysis evaluating the economic viability of hydrogen for medium- to large-scale electrical energy storage applications compared with three other storage technologies: batteries, pumped hydro, and compressed air energy storage (CAES).

  1. Command Process Modeling & Risk Analysis

    Science.gov (United States)

    Meshkat, Leila

    2011-01-01

    Commanding Errors may be caused by a variety of root causes. It's important to understand the relative significance of each of these causes for making institutional investment decisions. One of these causes is the lack of standardized processes and procedures for command and control. We mitigate this problem by building periodic tables and models corresponding to key functions within it. These models include simulation analysis and probabilistic risk assessment models.

  2. X-ray structure determination and analysis of hydrogen interactions ...

    Indian Academy of Sciences (India)

    The crystal structure of 3,3′-dimethoxybiphenyl has been determined by X-ray diffraction methods with an aim of describing the hydrogen interaction in biphenyl derivatives. The title compound crystallizes in monoclinic space group 21/ with unit cell dimensions, = 7.706(1), = 11.745(2), = 12.721(2) Å, ...

  3. Analysis of the performance of hydrogen maser clocks at the ...

    African Journals Online (AJOL)

    Cilence

    Hydrogen maser frequency standards are commonly utilised in various space geodetic techniques such as Very Long Baseline Interferometry (VLBI) as local reference clocks. The. Hartebeesthoek Radio Astronomy Observatory in South Africa is currently operating two maser frequency standards i.e., an EFOS28 and an ...

  4. Analysis of the performance of hydrogen maser clocks at the ...

    African Journals Online (AJOL)

    Hydrogen maser frequency standards are commonly utilised in various space geodetic techniques such as Very Long Baseline Interferometry (VLBI) as local reference clocks. The Hartebeesthoek Radio Astronomy Observatory in South Africa is currently operating two maser frequency standards i.e., an EFOS28 and an ...

  5. Effectiveness of the Hydrogen Sulfide Test as a Water Quality Indicator for Diarrhea Risk in Rural Bangladesh.

    Science.gov (United States)

    Islam, Mahfuza; Ercumen, Ayse; Naser, Abu Mohd; Unicomb, Leanne; Rahman, Mahbubur; Arnold, Benjamin F; Colford, John M; Luby, Stephen P

    2017-12-01

    Microbiological water quality is usually assessed by the identification of Escherichia coli ( E. coli ), a fecal indicator. The hydrogen sulfide (H 2 S) test is an inexpensive, easy-to-use, and portable alternative field-based water quality test. Our study evaluated the H 2 S test's effectiveness as a water quality indicator for diarrhea risk. Field workers collected stored drinking water samples for H 2 S analysis and detection of E. coli by membrane filtration and measured caregiver-reported diarrhea among children trend. H 2 S test sensitivity, PPV, and NPV increased with increasing E. coli levels, consistent with previous evidence that the H 2 S test is a useful water quality tool in high-contamination settings. However, our results suggest that the H 2 S test is not an effective indicator for waterborne diarrhea.

  6. 38 CFR 75.115 - Risk analysis.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Risk analysis. 75.115...) INFORMATION SECURITY MATTERS Data Breaches § 75.115 Risk analysis. If a data breach involving sensitive... analysis or VA's Office of Inspector General conducts an independent risk analysis of the data breach. The...

  7. Hydrogen isotope analysis of amino acids and whole cells reflects biosynthetic processing of nutrient- and water-derived hydrogen

    Science.gov (United States)

    Griffin, P.; Newsome, S.; Steele, A.; Fogel, M. L.

    2011-12-01

    Hydrogen (H) isotopes serve as sensitive tracers of biochemical processes that can be exploited to answer critical questions in biogeochemistry, ecology, and microbiology. Despite this apparent utility, relatively little is known about the specific mechanisms of H isotope fractionation involved in biosynthesis. In order to understand how organisms incorporate hydrogen from their chemical milieu into biomass, we have cultured the model bacterium E. coli MG1655 in a variety of media composed of deuterium-labeled nutrients and waters. Isotopic analysis of bulk cell mass reveals that the H fractionation between media water and cell material varies as a function of the nutrient source, with commonly used organic food sources (glucose and tryptone) leading to far smaller fractionation signals than non-standard ones (such as formamide, adenine, and urea). In addition, we have completed compound specific isotope analysis of amino acids using combined GC-IRMS. Amino acids harvested from E. coli cultured on glucose in water of varied D/H composition posses an extraordinary range of isotopic compositions (400-600 %). Furthermore, these amino acids follow a systematic distribution of D/H where proline is always heaviest and glycine is always lightest. However, when the short-chain peptide tryptone is used in place of glucose, only the non-essential amino acids reflect media water D/H values, suggesting the direct incorporation of some media-borne amino acids into cellular protein. These observations provide a foundation for understanding the cellular routing of hydrogen obtained from food and water sources and indicate that D/H analysis can serve as a powerful probe of biological function.

  8. Use of triphenyl phosphate as risk mitigant for metal amide hydrogen storage materials

    Science.gov (United States)

    Cortes-Concepcion, Jose A.; Anton, Donald L.

    2016-04-26

    A process in a resulting product of the process in which a hydrogen storage metal amide is modified by a ball milling process using an additive of TPP. The resulting product provides for a hydrogen storage metal amide having a coating that renders the hydrogen storage metal amide resistant to air, ambient moisture, and liquid water while improving useful hydrogen storage and release kinetics.

  9. Risk analysis of highly combustible gas storage, supply, and distribution systems in PWR plants

    Energy Technology Data Exchange (ETDEWEB)

    Simion, G.P. [Science Applications International Corp., Albuquerque, NM (United States); VanHorn, R.L.; Smith, C.L.; Bickel, J.H.; Sattison, M.B. [EG and G Idaho, Inc., Idaho Falls, ID (United States); Bulmahn, K.D. [SCIENTECH, Inc., Idaho Falls, ID (United States)

    1993-06-01

    This report presents the evaluation of the potential safety concerns for pressurized water reactors (PWRs) identified in Generic Safety Issue 106, Piping and the Use of Highly Combustible Gases in Vital Areas. A Westinghouse four-loop PWR plant was analyzed for the risk due to the use of combustible gases (predominantly hydrogen) within the plant. The analysis evaluated an actual hydrogen distribution configuration and conducted several sensitivity studies to determine the potential variability among PWRs. The sensitivity studies were based on hydrogen and safety-related equipment configurations observed at other PWRs within the United States. Several options for improving the hydrogen distribution system design were identified and evaluated for their effect on risk and core damage frequency. A cost/benefit analysis was performed to determine whether alternatives considered were justifiable based on the safety improvement and economics of each possible improvement.

  10. Hydrogen Analysis with the Sandia ParaChoice Model.

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Rebecca Sobel [Sandia National Lab. (SNL-CA), Livermore, CA (United States); West, Todd H. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2017-07-01

    In the coming decades, light-duty vehicle options and their supporting infrastructure must undergo significant transformations to achieve aggressive national targets for reducing petroleum consumption and lowering greenhouse gas emissions. FCEVs, battery and hybrid electric vehicles, and biofuels are among the promising advanced technology options. This project examines the market penetration of FCEVs in a range of market segments, and in different energy, technology, and policy futures. Analyses are conducted in the context of varying hydrogen production and distribution pathways, as well as public infrastructure availability, fuel (gasoline, ethanol, hydrogen) and electricity costs, vehicle costs and fuel economies to better understand under what conditions, and for which market segments, FCEVs can best compete with battery electric and other alternative fuel vehicles.

  11. X-ray structure determination and analysis of hydrogen interactions ...

    Indian Academy of Sciences (India)

    Unknown

    with an aim of describing the hydrogen interaction in biphenyl derivatives. The title compound crystallizes in monoclinic space group P21/c with unit cell dimensions, a = 7⋅706(1), b = 11⋅745(2), c = 12⋅721(2) Å, β = 92⋅31(1)°,. Z = 4 and its structure has been refined up to the reliability index of 3⋅8%. The average torsion ...

  12. Comparative thermoeconomic analysis of hydrogen production by water electrolysis and by ethanol steam reforming

    Energy Technology Data Exchange (ETDEWEB)

    Riveros-Godoy, Gustavo; Chavez-Rodriguez, Mauro; Cavaliero, Carla [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Mechanical Engineering School], Email: garg@fem.unicamp.br

    2010-07-01

    Hydrogen is the focus of this work that evaluates in comparative form through thermo economic analysis two hydrogen production processes: water electrolysis and ethanol steam reforming. Even though technical-economical barriers still exist for the development of an economy based on hydrogen, these difficulties are opportunities for the appearance of new business of goods and services, diversification of the energy mix, focus of research activities, development and support to provide sustainability to the new economy. Exergy and rational efficiency concept are used to make a comparison between both processes. (author)

  13. Multi-criteria analysis on how to select solar radiation hydrogen production system

    Science.gov (United States)

    Badea, G.; Naghiu, G. S.; Felseghi, R.-A.; Rǎboacǎ, S.; Aşchilean, I.; Giurca, I.

    2015-12-01

    The purpose of this article is to present a method of selecting hydrogen-production systems using the electric power obtained in photovoltaic systems, and as a selecting method, we suggest the use of the Advanced Multi-Criteria Analysis based on the FRISCO formula. According to the case study on how to select the solar radiation hydrogen production system, the most convenient alternative is the alternative A4, namely the technical solution involving a hydrogen production system based on the electrolysis of water vapor obtained with concentrated solar thermal systems and electrical power obtained using concentrating photovoltaic systems.

  14. Thermodynamic analysis of alternate energy carriers, hydrogen and chemical heat pipes

    Science.gov (United States)

    Cox, K. E.; Carty, R. H.; Conger, W. L.; Soliman, M. A.; Funk, J. E.

    1976-01-01

    Hydrogen and chemical heat pipes were proposed as methods of transporting energy from a primary energy source (nuclear, solar) to the user. In the chemical heat pipe system, primary energy is transformed into the energy of a reversible chemical reaction; the chemical species are then transmitted or stored until the energy is required. Analysis of thermochemical hydrogen schemes and chemical heat pipe systems on a second law efficiency or available work basis show that hydrogen is superior especially if the end use of the chemical heat pipe is electrical power.

  15. Hydrogen Safety Project chemical analysis support task: Window ``C`` volatile organic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, B.M.; Stromatt, R.W.; Ross, G.A.; Hoope, E.A.

    1992-01-01

    This data package contains the results obtained by Pacific Northwest Laboratory (PNL) staff in the characterization of samples for the 101-SY Hydrogen Safety Project. The samples were submitted for analysis by Westinghouse Hanford Company (WHC) under the Technical Project Plan (TPP) 17667 and the Quality Assurance Plan MCS-027. They came from a core taken during Window ``C`` after the May 1991 gas release event. The analytical procedures required for analysis were defined in the Test Instructions (TI) prepared by the PNL 101-SY Analytical Chemistry Laboratory (ACL) Project Management Office in accordance with the TPP and the QA Plan. The requested analysis for these samples was volatile organic analysis. The quality control (QC) requirements for each sample are defined in the Test Instructions for each sample. The QC requirements outlined in the procedures and requested in the WHC statement of work were followed.

  16. Hydrogen Safety Project chemical analysis support task: Window C'' volatile organic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, B.M.; Stromatt, R.W.; Ross, G.A.; Hoope, E.A.

    1992-01-01

    This data package contains the results obtained by Pacific Northwest Laboratory (PNL) staff in the characterization of samples for the 101-SY Hydrogen Safety Project. The samples were submitted for analysis by Westinghouse Hanford Company (WHC) under the Technical Project Plan (TPP) 17667 and the Quality Assurance Plan MCS-027. They came from a core taken during Window C'' after the May 1991 gas release event. The analytical procedures required for analysis were defined in the Test Instructions (TI) prepared by the PNL 101-SY Analytical Chemistry Laboratory (ACL) Project Management Office in accordance with the TPP and the QA Plan. The requested analysis for these samples was volatile organic analysis. The quality control (QC) requirements for each sample are defined in the Test Instructions for each sample. The QC requirements outlined in the procedures and requested in the WHC statement of work were followed.

  17. Hydrogen fluoride (HF) substance flow analysis for safe and sustainable chemical industry.

    Science.gov (United States)

    Kim, Junbeum; Hwang, Yongwoo; Yoo, Mijin; Chen, Sha; Lee, Ik-Mo

    2017-11-01

    In this study, the chemical substance flow of hydrogen fluoride (hydrofluoric acid, HF) in domestic chemical industries in 2014 was analyzed in order to provide a basic material and information for the establishment of organized management system to ensure safety during HF applications. A total of 44,751 tons of HF was made by four domestic companies (in 2014); import amount was 95,984 tons in 2014 while 21,579 tons of HF was imported in 2005. The export amount of HF was 2180 tons, of which 2074 ton (China, 1422 tons, U.S. 524 tons, and Malaysia, 128 tons) was exported for the manufacturing of semiconductors. Based on the export and import amounts, it can be inferred that HF was used for manufacturing semiconductors. The industries applications of 161,123 tons of HF were as follows: manufacturing of basic inorganic chemical substance (27,937 tons), manufacturing of other chemical products such as detergents (28,208 tons), manufacturing of flat display (24,896 tons), and manufacturing of glass container package (22,002 tons). In this study, an analysis of the chemical substance flow showed that HF was mainly used in the semiconductor industry as well as glass container manufacturing. Combined with other risk management tools and approaches in the chemical industry, the chemical substance flow analysis (CSFA) can be a useful tool and method for assessment and management. The current CSFA results provide useful information for policy making in the chemical industry and national systems. Graphical abstract Hydrogen fluoride chemical substance flows in 2014 in South Korea.

  18. RISK ANALYSIS IN MILK PROCESSING

    Directory of Open Access Journals (Sweden)

    I. PIRVUTOIU

    2008-05-01

    Full Text Available This paper aimed to evaluate Risk bankruptcy using “Score Method” based on Canon and Holder’s Model. The data were collected from the Balance Sheet and Profit and Loss Account for the period 2005-2007, recorded by a Meat processing Plant (Rador Commercial Company .The study has put in evidence the financial situation of the company,the level of the main financial ratios fundamenting the calculation of Z score function value in the three years The low values of Z score function recorded every year reflects that the company is still facing backruptcy. However , the worst situation was recorded in the years 2005 and 2006, when baknruptcy risk was ranging between 70 – 80 % . In the year 2007, the risk bankruptcy was lower, ranging between 50-70 % , as Z function recorded a value lower than 4 .For Meat processing companies such an analysis is compulsory at present as long as business environment is very risky in our country.

  19. Hazards Induced by Breach of Liquid Rocket Fuel Tanks: Conditions and Risks of Cryogenic Liquid Hydrogen-Oxygen Mixture Explosions

    Science.gov (United States)

    Osipov, Viatcheslav; Muratov, Cyrill; Hafiychuk, Halyna; Ponizovskya-Devine, Ekaterina; Smelyanskiy, Vadim; Mathias, Donovan; Lawrence, Scott; Werkheiser, Mary

    2011-01-01

    We analyze the data of purposeful rupture experiments with LOx and LH2 tanks, the Hydrogen-Oxygen Vertical Impact (HOVI) tests that were performed to clarify the ignition mechanisms, the explosive power of cryogenic H2/Ox mixtures under different conditions, and to elucidate the puzzling source of the initial formation of flames near the intertank section during the Challenger disaster. We carry out a physics-based analysis of general explosions scenarios for cryogenic gaseous H2/Ox mixtures and determine their realizability conditions, using the well-established simplified models from the detonation and deflagration theory. We study the features of aerosol H2/Ox mixture combustion and show, in particular, that aerosols intensify the deflagration flames and can induce detonation for any ignition mechanism. We propose a cavitation-induced mechanism of self-ignition of cryogenic H2/Ox mixtures that may be realized when gaseous H2 and Ox flows are mixed with a liquid Ox turbulent stream, as occurred in all HOVI tests. We present an overview of the HOVI tests to make conclusion on the risk of strong explosions in possible liquid rocket incidents and provide a semi-quantitative interpretation of the HOVI data based on aerosol combustion. We uncover the most dangerous situations and discuss the foreseeable risks which can arise in space missions and lead to tragic outcomes. Our analysis relates to only unconfined mixtures that are likely to arise as a result of liquid propellant space vehicle incidents.

  20. Hydrogen Fuel Cell Analysis: Lessons Learned from Stationary Power Generation Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Scott E. Grasman; John W. Sheffield; Fatih Dogan; Sunggyu Lee; Umit O. Koylu; Angie Rolufs

    2010-04-30

    This study considered opportunities for hydrogen in stationary applications in order to make recommendations related to RD&D strategies that incorporate lessons learned and best practices from relevant national and international stationary power efforts, as well as cost and environmental modeling of pathways. The study analyzed the different strategies utilized in power generation systems and identified the different challenges and opportunities for producing and using hydrogen as an energy carrier. Specific objectives included both a synopsis/critical analysis of lessons learned from previous stationary power programs and recommendations for a strategy for hydrogen infrastructure deployment. This strategy incorporates all hydrogen pathways and a combination of distributed power generating stations, and provides an overview of stationary power markets, benefits of hydrogen-based stationary power systems, and competitive and technological challenges. The motivation for this project was to identify the lessons learned from prior stationary power programs, including the most significant obstacles, how these obstacles have been approached, outcomes of the programs, and how this information can be used by the Hydrogen, Fuel Cells & Infrastructure Technologies Program to meet program objectives primarily related to hydrogen pathway technologies (production, storage, and delivery) and implementation of fuel cell technologies for distributed stationary power. In addition, the lessons learned address environmental and safety concerns, including codes and standards, and education of key stakeholders.

  1. PNNL Development and Analysis of Material-Based Hydrogen Storage Systems for the Hydrogen Storage Engineering Center of Excellence

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Kriston P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Alvine, Kyle J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Kenneth I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Klymyshyn, Nicholas A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pires, Richard P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ronnebro, Ewa [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Simmons, Kevin L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Weimar, Mark R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westman, Matthew P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-02-29

    The Hydrogen Storage Engineering Center of Excellence is a team of universities, industrial corporations, and federal laboratories with the mandate to develop lower-pressure, materials-based, hydrogen storage systems for hydrogen fuel cell light-duty vehicles. Although not engaged in the development of new hydrogen storage materials themselves, it is an engineering center that addresses engineering challenges associated with the currently available hydrogen storage materials. Three material-based approaches to hydrogen storage are being researched: 1) chemical hydrogen storage materials 2) cryo-adsorbents, and 3) metal hydrides. As a member of this Center, Pacific Northwest National Laboratory (PNNL) has been involved in the design and evaluation of systems developed with each of these three hydrogen storage materials. This report is a compilation of the work performed by PNNL for this Center.

  2. Shifts in metabolic hydrogen sinks in the methanogenesis-inhibited ruminal fermentation: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Emilio M. Ungerfeld

    2015-02-01

    Full Text Available Maximizing the flow of metabolic hydrogen ([H] in the rumen away from CH4 and towards volatile fatty acids (VFA would increase the efficiency of ruminant production and decrease its environmental impact. The objectives of this meta-analysis were: i To quantify shifts in metabolic hydrogen sinks when inhibiting ruminal methanogenesis in vitro; and ii To understand the variation in shifts of metabolic hydrogen sinks among experiments and between batch and continuous cultures systems when methanogenesis is inhibited. Batch (28 experiments, N=193 and continuous (16 experiments, N=79 culture databases of experiments with at least 50% inhibition in CH4 production were compiled. Inhibiting methanogenesis generally resulted in less fermentation and digestion in most batch culture, but not in most continuous culture, experiments. Inhibiting CH4 production in batch cultures resulted in redirection of metabolic hydrogen towards propionate and H2 but not butyrate. In continuous cultures, there was no overall metabolic hydrogen redirection towards propionate or butyrate, and H2 as a proportion of metabolic hydrogen spared from CH4 production was numerically smaller compared to batch cultures. Dihydrogen accumulation was affected by type of substrate and methanogenesis inhibitor, with highly fermentable substrates resulting in greater redirection of metabolic hydrogen towards H2 when inhibiting methanogenesis, and some oils causing small or no H2 accumulation. In both batch and continuous culture, there was a decrease in metabolic hydrogen recovered as the sum of propionate, butyrate, CH4 and H2 when inhibiting methanogenesis, and it is speculated that as CH4 production decreases metabolic hydrogen could be increasingly incorporated into formate, microbial biomass, and, perhaps, reductive acetogenesis in continuous cultures. Energetic benefits of inhibiting methanogenesis depended on the inhibitor and its concentration and on the in vitro system.

  3. Targets for bulk hydrogen analysis using thermal neutrons

    CERN Document Server

    Csikai, J; Buczko, C M

    2002-01-01

    The reflection property of substances can be characterized by the reflection cross-section of thermal neutrons, sigma subbeta. A combination of the targets with thin polyethylene foils allowed an estimation of the flux depression of thermal neutrons caused by a bulk sample containing highly absorbing elements or compounds. Some new and more accurate sigma subbeta values were determined by using the combined target arrangement. For the ratio, R of the reflection and the elastic scattering cross-sections of thermal neutrons, R=sigma subbeta/sigma sub E sub L a value of 0.60+-0.02 was found on the basis of the data obtained for a number of elements from H to Pb. Using this correlation factor, and the sigma sub E sub L values, the unknown sigma subbeta data can be deduced. The equivalent thicknesses, to polyethylene or hydrogen, of the different target materials were determined from the sigma subbeta values.

  4. Entropy and complexity analysis of hydrogenic Rydberg atoms

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rosa, S. [Instituto Carlos I de Fisica Teorica y Computacional, Universidad de Granada, 18071-Granada (Spain); Departamento de Fisica Aplicada II, Universidad de Sevilla, 41012-Sevilla (Spain); Toranzo, I. V.; Dehesa, J. S. [Instituto Carlos I de Fisica Teorica y Computacional, Universidad de Granada, 18071-Granada (Spain); Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, 18071-Granada (Spain); Sanchez-Moreno, P. [Instituto Carlos I de Fisica Teorica y Computacional, Universidad de Granada, 18071-Granada (Spain); Departamento de Matematica Aplicada, Universidad de Granada, 18071-Granada (Spain)

    2013-05-15

    The internal disorder of hydrogenic Rydberg atoms as contained in their position and momentum probability densities is examined by means of the following information-theoretic spreading quantities: the radial and logarithmic expectation values, the Shannon entropy, and the Fisher information. As well, the complexity measures of Cramer-Rao, Fisher-Shannon, and Lopez Ruiz-Mancini-Calvet types are investigated in both reciprocal spaces. The leading term of these quantities is rigorously calculated by use of the asymptotic properties of the concomitant entropic functionals of the Laguerre and Gegenbauer orthogonal polynomials which control the wavefunctions of the Rydberg states in both position and momentum spaces. The associated generalized Heisenberg-like, logarithmic and entropic uncertainty relations are also given. Finally, application to linear (l= 0), circular (l=n- 1), and quasicircular (l=n- 2) states is explicitly done.

  5. Analysis of hydrogen storage in nanoporous materials for low carbon energy applications.

    Science.gov (United States)

    Bimbo, Nuno; Ting, Valeska P; Hruzewicz-Kołodziejczyk, Anna; Mays, Timothy J

    2011-01-01

    A robust, simple methodology for analysis of isotherms for the adsorption of fluids above their critical temperature onto nanostructured materials is presented. The analysis of hydrogen adsorption in a metal-organic framework is used as an example to illustrate the methodology, which allows the estimation of the absolute adsorption into nanoporous systems. Further advantages of employing this analysis are that adsorption systems can be described using a small number of parameters, and that excess and absolute isotherms can be extrapolated and used to predict adsorption behaviour at higher pressures and over different temperature ranges. Thermodynamic calculations, using the exact Clapeyron equation and the Clausius-Clapeyron approximation applied to the example dataset, are presented and compared. Conventional compression of hydrogen and adsorptive storage are evaluated, with an illustration of the pressure ranges in which adsorption facilitates storage of greater volumes of hydrogen than normal compression in the same operating conditions.

  6. Feasibility analysis of a hydrogen backup power system for Russian telecom market

    Science.gov (United States)

    Borzenko, V. I.; Dunikov, D. O.

    2017-11-01

    We performed feasibility analysis of 10 kW hydrogen backup power system (H2BS) consisting of a water electrolyzer, a metal hydride hydrogen storage and a fuel cell. Capital investments in H2BS are mostly determined by the costs of the PEM electrolyzer, the fuel cell and solid state hydrogen storage materials, for single unit or small series manufacture the cost of AB5-type intermetallic compound can reach 50% of total system cost. Today the capital investments in H2BS are 3 times higher than in conventional lead-acid system of the same capacity. Wide distribution of fuel cell hydrogen vehicles, development of hydrogen infrastructure, and mass production of hydrogen power systems will for sure lower capital investments in fuel cell backup power. Operational expenditures for H2BS is only 15% from the expenditures for lead acid systems, and after 4-5 years of exploitation the total cost of ownership will become lower than for batteries.

  7. Development of a new method for hydrogen isotope analysis of trace hydrocarbons in natural gas samples

    Directory of Open Access Journals (Sweden)

    Xibin Wang

    2016-12-01

    Full Text Available A new method had been developed for the analysis of hydrogen isotopic composition of trace hydrocarbons in natural gas samples by using solid phase microextraction (SPME combined with gas chromatography-isotope ratio mass spectrometry (GC/IRMS. In this study, the SPME technique had been initially introduced to achieve the enrichment of trace content of hydrocarbons with low abundance and coupled to GC/IRMS for hydrogen isotopic analysis. The main parameters, including the equilibration time, extraction temperature, and the fiber type, were systematically optimized. The results not only demonstrated that high extraction yield was true but also shows that the hydrogen isotopic fractionation was not observed during the extraction process, when the SPME device fitted with polydimethylsiloxane/divinylbenzene/carbon molecular sieve (PDMS/DVB/CAR fiber. The applications of SPME-GC/IRMS method were evaluated by using natural gas samples collected from different sedimentary basins; the standard deviation (SD was better than 4‰ for reproducible measurements; and also, the hydrogen isotope values from C1 to C9 can be obtained with satisfying repeatability. The SPME-GC/IRMS method fitted with PDMS/DVB/CAR fiber is well suited for the preconcentration of trace hydrocarbons, and provides a reliable hydrogen isotopic analysis for trace hydrocarbons in natural gas samples.

  8. Hydrogen Financial Analysis Scenario Tool (H2FAST). Web Tool User's Manual

    Energy Technology Data Exchange (ETDEWEB)

    Bush, B. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Penev, M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Melaina, M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zuboy, J. [Independent Consultant, Golden, CO (United States)

    2015-05-11

    The Hydrogen Financial Analysis Scenario Tool (H2FAST) provides a quick and convenient indepth financial analysis for hydrogen fueling stations. This manual describes how to use the H2FAST web tool, which is one of three H2FAST formats developed by the National Renewable Energy Laboratory (NREL). Although all of the formats are based on the same financial computations and conform to generally accepted accounting principles (FASAB 2014, Investopedia 2014), each format provides a different level of complexity and user interactivity.

  9. Streamlining project delivery through risk analysis.

    Science.gov (United States)

    2015-08-01

    Project delivery is a significant area of concern and is subject to several risks throughout Plan Development : Process (PDP). These risks are attributed to major areas of project development, such as environmental : analysis, right-of-way (ROW) acqu...

  10. Analysis and Design of Cryogenic Pressure Vessels for Automotive Hydrogen Storage

    Science.gov (United States)

    Espinosa-Loza, Francisco Javier

    Cryogenic pressure vessels maximize hydrogen storage density by combining the high pressure (350-700 bar) typical of today's composite pressure vessels with the cryogenic temperature (as low as 25 K) typical of low pressure liquid hydrogen vessels. Cryogenic pressure vessels comprise a high-pressure inner vessel made of carbon fiber-coated metal (similar to those used for storage of compressed gas), a vacuum space filled with numerous sheets of highly reflective metalized plastic (for high performance thermal insulation), and a metallic outer jacket. High density of hydrogen storage is key to practical hydrogen-fueled transportation by enabling (1) long-range (500+ km) transportation with high capacity vessels that fit within available spaces in the vehicle, and (2) reduced cost per kilogram of hydrogen stored through reduced need for expensive structural material (carbon fiber composite) necessary to make the vessel. Low temperature of storage also leads to reduced expansion energy (by an order of magnitude or more vs. ambient temperature compressed gas storage), potentially providing important safety advantages. All this is accomplished while simultaneously avoiding fuel venting typical of cryogenic vessels for all practical use scenarios. This dissertation describes the work necessary for developing and demonstrating successive generations of cryogenic pressure vessels demonstrated at Lawrence Livermore National Laboratory. The work included (1) conceptual design, (2) detailed system design (3) structural analysis of cryogenic pressure vessels, (4) thermal analysis of heat transfer through cryogenic supports and vacuum multilayer insulation, and (5) experimental demonstration. Aside from succeeding in demonstrating a hydrogen storage approach that has established all the world records for hydrogen storage on vehicles (longest driving range, maximum hydrogen storage density, and maximum containment of cryogenic hydrogen without venting), the work also

  11. Sizing and economic analysis of stand alone photovoltaic system with hydrogen storage

    Science.gov (United States)

    Nordin, N. D.; Rahman, H. A.

    2017-11-01

    This paper proposes a design steps in sizing of standalone photovoltaic system with hydrogen storage using intuitive method. The main advantage of this method is it uses a direct mathematical approach to find system’s size based on daily load consumption and average irradiation data. The keys of system design are to satisfy a pre-determined load requirement and maintain hydrogen storage’s state of charge during low solar irradiation period. To test the effectiveness of the proposed method, a case study is conducted using Kuala Lumpur’s generated meteorological data and rural area’s typical daily load profile of 2.215 kWh. In addition, an economic analysis is performed to appraise the proposed system feasibility. The finding shows that the levelized cost of energy for proposed system is RM 1.98 kWh. However, based on sizing results obtained using a published method with AGM battery as back-up supply, the system cost is lower and more economically viable. The feasibility of PV system with hydrogen storage can be improved if the efficiency of hydrogen storage technologies significantly increases in the future. Hence, a sensitivity analysis is performed to verify the effect of electrolyzer and fuel cell efficiencies towards levelized cost of energy. Efficiencies of electrolyzer and fuel cell available in current market are validated using laboratory’s experimental data. This finding is needed to envisage the applicability of photovoltaic system with hydrogen storage as a future power supply source in Malaysia.

  12. Sensitivity analysis in quantitative microbial risk assessment.

    Science.gov (United States)

    Zwieterin, M H; van Gerwen, S J

    2000-07-15

    The occurrence of foodborne disease remains a widespread problem in both the developing and the developed world. A systematic and quantitative evaluation of food safety is important to control the risk of foodborne diseases. World-wide, many initiatives are being taken to develop quantitative risk analysis. However, the quantitative evaluation of food safety in all its aspects is very complex, especially since in many cases specific parameter values are not available. Often many variables have large statistical variability while the quantitative effect of various phenomena is unknown. Therefore, sensitivity analysis can be a useful tool to determine the main risk-determining phenomena, as well as the aspects that mainly determine the inaccuracy in the risk estimate. This paper presents three stages of sensitivity analysis. First, deterministic analysis selects the most relevant determinants for risk. Overlooking of exceptional, but relevant cases is prevented by a second, worst-case analysis. This analysis finds relevant process steps in worst-case situations, and shows the relevance of variations of factors for risk. The third, stochastic analysis, studies the effects of variations of factors for the variability of risk estimates. Care must be taken that the assumptions made as well as the results are clearly communicated. Stochastic risk estimates are, like deterministic ones, just as good (or bad) as the available data, and the stochastic analysis must not be used to mask lack of information. Sensitivity analysis is a valuable tool in quantitative risk assessment by determining critical aspects and effects of variations.

  13. Analysis of Simplified Hydrogen and Dust Explosion in the Vacuum Vessel Accident using MELCOR Code

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Soo Min; Moon, Sung Bo; Bang, In Cheol [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The failure of the confinement barriers inside a penetration line between the VV and a port cell initiates the accident. Air ingress in VV results in formation of hydrogen/air explosive mixture and further explosion. Hydrogen explosion is assumed to trigger a dust explosion which leads to a large pressure peak creating a connection between VV and NBI Cell. Any other components related to the accident other than VV, suppression tank (ST), port cell, NBI Cell and Gallery are ignored in the analysis. Additional Free volume is assumed connected to the VV to simulate hydrogen/dust explosions. Figure 1 presents schematics of modeling of thermal-hydraulic analysis used in the accident analysis. For ITER design, three volumes of accident analysis report (AAR) presents analysis of selected postulated events important in ITER safety studies including hypothetical events. MELCOR 1.8.2 code was chosen as one of the several codes to perform ITER safety analysis because it models wide range of physical phenomena such as thermal-hydraulics, heat transfer, and other phenomena including aerosol physics. MELCOR can also predict structural temperatures using energy produced by radioactive heat or chemical reactions. Analysis has shown that hydrogen/dust explosion damaged the VV confinement barriers transporting dust from VV to the port cell, NBI cell and other penetrating lines. Unlike the accident analysis performed in the accident analysis report (AAR), the radioactive material was released into the environment shortly after the event. Simplified accident analysis was performed in attempt to perform fast safety analysis, however, multiple components and initial conditions not under consideration caused significant difference from the AAR analysis results.

  14. Computer simulation for risk management: Hydrogen refueling stations and water supply of a large region

    DEFF Research Database (Denmark)

    Markert, Frank; Kozine, Igor

    2012-01-01

    by the conventional reliability analysis models and systems analysis methods. An improvement and alternative to the conventional approach is seen in using Discrete Event Simulation (DES) models that can better account for the dynamic dimensions of the systems. The paper will describe the authors’ experience......Risk management of complex environments needs the supportive tools provided by computer models and simulation. During time, various tools have been developed and been applied with different degree of success. The still lasting increase in computer power and the associated development potentials...... stimulate and promote their application within risk management. Today, computer supported models as fault trees, event trees and Bayesian networks are commonly regarded and applied as standard tools for reliability and risk practitioners. There are though some important features that hardly can be captured...

  15. Environmental and Socio-Economic Analysis of Naphtha Reforming Hydrogen Energy Using Input-Output Tables: A Case Study from Japan

    Directory of Open Access Journals (Sweden)

    Shunichi Hienuki

    2017-08-01

    Full Text Available Comprehensive risk assessment across multiple fields is required to assess the potential utility of hydrogen energy technology. In this research, we analyzed environmental and socio-economic effects during the entire life cycle of a hydrogen energy system using input-output tables. The target system included hydrogen production by naphtha reforming, transportation to hydrogen stations, and FCV (Fuel Cell Vehicle refilling. The results indicated that 31%, 44%, and 9% of the production, employment, and greenhouse gas (GHG emission effects, respectively, during the manufacturing and construction stages were temporary. During the continuous operation and maintenance stages, these values were found to be 69%, 56%, and 91%, respectively. The effect of naphtha reforming was dominant in GHG emissions and the effect of electrical power input on the entire system was significant. Production and employment had notable effects in both the direct and indirect sectors, including manufacturing (pumps, compressors, and chemical machinery and services (equipment maintenance and trade. This study used data to introduce a life cycle perspective to environmental and socio-economic analysis of hydrogen energy systems and the results will contribute to their comprehensive risk assessment in the future.

  16. Scattering influences in quantitative fission neutron radiography for the in situ analysis of hydrogen distribution in metal hydrides

    Science.gov (United States)

    Börries, S.; Metz, O.; Pranzas, P. K.; Bücherl, T.; Söllradl, S.; Dornheim, M.; Klassen, T.; Schreyer, A.

    2015-10-01

    In situ neutron radiography allows for the time-resolved study of hydrogen distribution in metal hydrides. However, for a precise quantitative investigation of a time-dependent hydrogen content within a host material, an exact knowledge of the corresponding attenuation coefficient is necessary. Additionally, the effect of scattering has to be considered as it is known to violate Beer's law, which is used to determine the amount of hydrogen from a measured intensity distribution. Within this study, we used a metal hydride inside two different hydrogen storage tanks as host systems, consisting of steel and aluminum. The neutron beam attenuation by hydrogen was investigated in these two different setups during the hydrogen absorption process. A linear correlation to the amount of absorbed hydrogen was found, allowing for a readily quantitative investigation. Further, an analysis of scattering contributions on the measured intensity distributions was performed and is described in detail.

  17. Hydrogen Financial Analysis Scenario Tool (H2FAST); NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Melaina, Marc

    2015-04-21

    This presentation describes the Hydrogen Financial Analysis Scenario Tool, H2FAST, and provides an overview of each of the three H2FAST formats: the H2FAST web tool, the H2FAST Excel spreadsheet, and the H2FAST Business Case Scenario (BCS) tool. Examples are presented to illustrate the types of questions that H2FAST can help answer.

  18. Overview of the Hydrogen Financial Analysis Scenario Tool (H2FAST); NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Melaina, Marc; Bush, Brian; Penev, Michael

    2015-05-12

    This presentation provides an introduction to the Hydrogen Financial Analysis Scenario Tool (H2FAST) and includes an overview of each of the three versions of H2FAST: the Web tool, the Excel spreadsheet version, and the beta version of the H2FAST Business Case Scenario tool.

  19. Introduction of Hydrogen Peroxide as an Oxidant in Flow Injection Analysis: Speciation of Cr(III) and Cr(VI)

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    1998-01-01

    Hydrogen peroxide was used as an oxidant in Flow Injection Analysis (FIA). The formation of gaseous components during the analysis was suppressed by maintaining a concentration lower than 0.15% of hydrogen peroxide in 0.1 M NaOH. By this method Cr(III) was oxidised on-line to Cr(VI) which...

  20. Carbon Fiber Risk Analysis. [conference

    Science.gov (United States)

    1979-01-01

    The scope and status of the effort to assess the risks associated with the accidental release of carbon/graphite fibers from civil aircraft is presented. Vulnerability of electrical and electronic equipment to carbon fibers, dispersal of carbon fibers, effectiveness of filtering systems, impact of fiber induced failures, and risk methodology are among the topics covered.

  1. Analysis and optimization of a tubular SOFC, using nuclear hydrogen as fuel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Daniel G.; Parra, Lazaro R.G.; Fernandez, Carlos R.G., E-mail: dgr@instec.cu [Instituto Superior de Tecnologias y Ciencias Aplicadas, Habana (Cuba). Dept. de Ingenieria Nuclear; Lira, Carlos A.B.O., E-mail: cabol@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2013-07-01

    One of the main areas of hydrogen uses as an energy carrier is in fuel cells of high standards as solid oxide fuel cells (SOFC). The SOFCs are fuel cells operate at high temperatures making them ideal for use in large power systems, suitable for distributed generation of electricity. Optimization and analysis of these electrochemical devices is an area of great current study. The computational fluid dynamics software (CFD) have unique advantages for analyzing the influence of design parameters on the efficiency of fuel cells. This paper presents a SOFC design cell which employ as fuel hydrogen produced by thermochemical water splitting cycle (I-S). There will be done the optimization of the main parameters thermodynamic and electrochemical cell operating to achieve top performance. Also will be estimate the cell efficiency and a production-consumption hydrogen system. (author)

  2. Control analysis of renewable energy system with hydrogen storage for residential applications

    Science.gov (United States)

    Bilodeau, A.; Agbossou, K.

    The combination of an electrolyzer and a fuel cell can provide peak power control in a decentralized/distributed power system. The electrolyzer produces hydrogen and oxygen from off-peak electricity generated by the renewable energy sources (wind turbine and photovoltaic array), for later use in the fuel cell to produce on-peak electricity. An issue related to this system is the control of the hydrogen loop (electrolyzer, tank, fuel cell). A number of control algorithms were developed to decide when to produce hydrogen and when to convert it back to electricity, most of them assuming that the electrolyzer and the fuel cell run alternatively to provide nominal power (full power). This paper presents a complete model of a stand-alone renewable energy system with hydrogen storage controlled by a dynamic fuzzy logic controller (FLC). In this system, batteries are used as energy buffers and for short time storage. To study the behavior of such a system, a complete model is developed by integrating the individual sub-models of the fuel cell, the electrolyzer, the power conditioning units, the hydrogen storage system, and the batteries. An analysis of the performances of the dynamic fuzzy logic controller is then presented. This model is useful for building efficient peak power control.

  3. Insulated Pressure Vessels for Vehicular Hydrogen Storage: Analysis and Performance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S M; Martinez-Frias, J; Garcia-Villazana, O; Espinosa-Loza, F

    2001-06-26

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures. Future activities also include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining certification for insulated pressure vessels.

  4. Numerical Analysis on Thermochemical Characteristics of a Hydrogen Iodine Decomposer in Sulfur-Iodine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T. H.; Lee, K. Y.; Shin, Y. J. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Choi, J. S.; Choi, J. H. [Korea Maritime and Ocean University, Busan (Korea, Republic of)

    2015-05-15

    In this study, to develop optimum decomposition reactor of HI to apply hydrogen process in thermochemical VHTR-SI cycle, operating characteristics of the HI decomposition reaction were investigated using the CFD code as a commercial program. Several factors, such as hydrogen production, heat of reaction, and temperature distribution, were studied to compare the device performance with that expected for device development. The CFD analysis for HI decomposition simulation was performed by applying the actual operation conditions and HI decomposer design. The hydrogen production depended on the STV ratio. In this study, predicted hydrogen production was 1.12, 1.99, and 3.10 mol/h for STV ratios of 0.3, 0.4, and 0.5, respectively. The hydrogen production at an STV ratio of 0.5 was higher than that at 0.3 by 2 mol/h. The inner temperature of the HI decomposer was studied in the form of contour images at ITC 1-5.

  5. Advances in Risk Analysis with Big Data.

    Science.gov (United States)

    Choi, Tsan-Ming; Lambert, James H

    2017-08-01

    With cloud computing, Internet-of-things, wireless sensors, social media, fast storage and retrieval, etc., organizations and enterprises have access to unprecedented amounts and varieties of data. Current risk analysis methodology and applications are experiencing related advances and breakthroughs. For example, highway operations data are readily available, and making use of them reduces risks of traffic crashes and travel delays. Massive data of financial and enterprise systems support decision making under risk by individuals, industries, regulators, etc. In this introductory article, we first discuss the meaning of big data for risk analysis. We then examine recent advances in risk analysis with big data in several topic areas. For each area, we identify and introduce the relevant articles that are featured in the special issue. We conclude with a discussion on future research opportunities. © 2017 Society for Risk Analysis.

  6. A comparative analysis of the cryo-compression and cryo-adsorption hydrogen storage methods

    Energy Technology Data Exchange (ETDEWEB)

    Petitpas, G [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Benard, P [Universite du Quebec a Trois-Rivieres (Canada); Klebanoff, L E [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Xiao, J [Universite du Quebec a Trois-Rivieres (Canada); Aceves, S M [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-07-01

    While conventional low-pressure LH₂ dewars have existed for decades, advanced methods of cryogenic hydrogen storage have recently been developed. These advanced methods are cryo-compression and cryo-adsorption hydrogen storage, which operate best in the temperature range 30–100 K. We present a comparative analysis of both approaches for cryogenic hydrogen storage, examining how pressure and/or sorbent materials are used to effectively increase onboard H₂ density and dormancy. We start by reviewing some basic aspects of LH₂ properties and conventional means of storing it. From there we describe the cryo-compression and cryo-adsorption hydrogen storage methods, and then explore the relationship between them, clarifying the materials science and physics of the two approaches in trying to solve the same hydrogen storage task (~5–8 kg H₂, typical of light duty vehicles). Assuming that the balance of plant and the available volume for the storage system in the vehicle are identical for both approaches, the comparison focuses on how the respective storage capacities, vessel weight and dormancy vary as a function of temperature, pressure and type of cryo-adsorption material (especially, powder MOF-5 and MIL-101). By performing a comparative analysis, we clarify the science of each approach individually, identify the regimes where the attributes of each can be maximized, elucidate the properties of these systems during refueling, and probe the possible benefits of a combined “hybrid” system with both cryo-adsorption and cryo-compression phenomena operating at the same time. In addition the relationships found between onboard H₂ capacity, pressure vessel and/or sorbent mass and dormancy as a function of rated pressure, type of sorbent material and fueling conditions are useful as general designing guidelines in future engineering efforts using these two hydrogen storage approaches.

  7. Analysis of Thermal and Reaction Times for Hydrogen Reduction of Lunar Regolith

    Science.gov (United States)

    Hegde, U.; Balasubramaniam, R.; Gokoglu, S.

    2009-01-01

    System analysis of oxygen production by hydrogen reduction of lunar regolith has shown the importance of the relative time scales for regolith heating and chemical reaction to overall performance. These values determine the sizing and power requirements of the system and also impact the number and operational phasing of reaction chambers. In this paper, a Nusselt number correlation analysis is performed to determine the heat transfer rates and regolith heat up times in a fluidized bed reactor heated by a central heating element (e.g., a resistively heated rod, or a solar concentrator heat pipe). A coupled chemical and transport model has also been developed for the chemical reduction of regolith by a continuous flow of hydrogen. The regolith conversion occurs on the surfaces of and within the regolith particles. Several important quantities are identified as a result of the above analyses. Reactor scale parameters include the void fraction (i.e., the fraction of the reactor volume not occupied by the regolith particles) and the residence time of hydrogen in the reactor. Particle scale quantities include the particle Reynolds number, the Archimedes number, and the time needed for hydrogen to diffuse into the pores of the regolith particles. The analysis is used to determine the heat up and reaction times and its application to NASA s oxygen production system modeling tool is noted.

  8. Hydrogen embrittlement I. Analysis of hydrogen-enhanced localized plasticity: Effect of hydrogen on the velocity of screw dislocations in α -Fe

    Science.gov (United States)

    Katzarov, Ivaylo H.; Pashov, Dimitar L.; Paxton, Anthony T.

    2017-08-01

    We demonstrate a kinetic Monte Carlo simulation tool, based on published data using first-principles quantum mechanics, applied to answer the question: under which conditions of stress, temperature, and nominal hydrogen concentration does the presence of hydrogen in iron increase or decrease the screw dislocation velocity? Furthermore, we examine the conditions under which hydrogen-induced shear localization is likely to occur. Our simulations yield quantitative data on dislocation velocity and the ranges of hydrogen concentration within which a large gradient of velocity as a function of concentration is expected to be observed and thereby contribute to a self-perpetuating localization of plasticity—a phenomenon that has been linked to hydrogen-induced fracture and fatigue failure in ultrahigh strength steel. We predict the effect of hydrogen in generating debris made up of edge dipoles trailing in the wake of gliding screw dislocations and their role in pinning. We also simulate the competing effects of softening by enhanced kink-pair generation and hardening by solute pinning. Our simulations act as a bridge between first-principles quantum mechanics and discrete dislocation dynamics, and at the same time offer the prospect of a fully physics-based dislocation dynamics method.

  9. Risk analysis and climate alteration

    Energy Technology Data Exchange (ETDEWEB)

    Hidy, G.M. (Electric Power Research Institute, Palo Alto, CA (United States))

    1993-01-01

    Largely absent from the recent climate debates have been careful, objective risk analyses that add insight into energy, environment and economic options. Such studies require a distillation of scientific knowledge combined with socio-economic considerations. In support of this goal, work has been initiated to develop an integrated risk assessment framework for climate change. Conceptually, risk analyses are facilitated by integrated assessment models. These include several analytical components. For the risk of climate alteration, the parts can be identified in terms of (a) policy formulation, (b) economic response, (c) greenhouse gas (GHG) dispersion, (d) climate change, (e) ecosystem effects and valuation, and (f) human system effects and valuation. Simple macro-economic models incorporating these components have been developed that have added insight into the costs and apparent benefits of GHG management options. These early, rudimentary models need to be greatly improved with new knowledge to better inform decision makers on optimal management strategies. The early results from integrated analyses have: (a) reinforced the importance of requiring risk-oriented information from general scientific investigation, (b) focused on the need for far better quantitative information on the environmental effects, and (c) identified the need for substantial improvement of information about human values and priorities in different cultural settings. Technological options for managing GHGs have looked at opportunities for improving the effectiveness of the electrical system, and the human management of biospheric processes. 12 refs., 1 fig., 1 tab.

  10. Powdered hydrogenation catalysts. An evaluation and characterization by thermal analysis and ESCA

    Energy Technology Data Exchange (ETDEWEB)

    Kosak, J.R.; Duch, M.W.

    1979-01-01

    An evaluation and characterization by thermal analysis and ESCA showed that both techniques are excellent tools for screening such catalysts, e.g., carbon-supported platinum (1, 4, or 5Vertical Bar3<) or palladium (5Vertical Bar3<) tested in the liquid-phase, batch hydrogenation of p-nitrotoluene at 120/sup 0/C and 500 psig hydrogen. Thermal analysis, a chemisorption technique combined with pressure differential scanning calorimetry, affords a fast, practical means for monitoring the reproducibility of both unreduced and reduced catalysts and yields direct information on catalyst behavior in the presence of hydrogen. ESCA measures relative metal dispersion and permits the evaluation of completeness of reduction in those catalysts after prereduction. The combination of the two techniques provides comparison data about metal dispersion on the support and information on the chemical state of the metal, the latter being particularly useful for characterizing catalyst selectivity. For unreduced or completely reduced catalysts, both techniques give similar hydrogenation performance predictions, but for prereduced catalysts with only partial metal conversion to the zero oxidation state, ESCA yields more reliable data.

  11. Engineering Analysis Studies for Preliminary Design of Lightweight Cryogenic Hydrogen Tanks in UAV Applications

    Science.gov (United States)

    Sullivan, Roy M.; Palko, Joseph L.; Tornabene, Robert T.; Bednarcyk, Brett A.; Powers, Lynn M.; Mital, Subodh K.; Smith, Lizalyn M.; Wang, Xiao-Yen J.; Hunter, James E.

    2006-01-01

    A series of engineering analysis studies were conducted to investigate the potential application of nanoclay-enhanced graphite/epoxy composites and polymer cross-linked silica aerogels in cryogenic hydrogen storage tank designs. This assessment focused on the application of these materials in spherical tank designs for unmanned aeronautic vehicles with mission durations of 14 days. Two cryogenic hydrogen tank design concepts were considered: a vacuum-jacketed design and a sandwiched construction with an aerogel insulating core. Analyses included thermal and structural analyses of the tank designs as well as an analysis of hydrogen diffusion to specify the material permeability requirements. The analyses also provided material property targets for the continued development of cross-linked aerogels and nanoclay-enhanced graphite/epoxy composites for cryogenic storage tank applications. The results reveal that a sandwiched construction with an aerogel core is not a viable design solution for a 14-day mission. A vacuum-jacketed design approach was shown to be far superior to an aerogel. Aerogel insulation may be feasible for shorter duration missions. The results also reveal that the application of nanoclay-enhanced graphite/epoxy should be limited to the construction of outer tanks in a vacuum-jacketed design, since a graphite/epoxy inner tank does not provide a significant weight savings over aluminum and since the ability of nanoclay-enhanced graphite/epoxy to limit hydrogen permeation is still in question.

  12. Risk analysis based on hazards interactions

    Science.gov (United States)

    Rossi, Lauro; Rudari, Roberto; Trasforini, Eva; De Angeli, Silvia; Becker, Joost

    2017-04-01

    Despite an increasing need for open, transparent, and credible multi-hazard risk assessment methods, models, and tools, the availability of comprehensive risk information needed to inform disaster risk reduction is limited, and the level of interaction across hazards is not systematically analysed. Risk assessment methodologies for different hazards often produce risk metrics that are not comparable. Hazard interactions (consecutive occurrence two or more different events) are generally neglected, resulting in strongly underestimated risk assessment in the most exposed areas. This study presents cases of interaction between different hazards, showing how subsidence can affect coastal and river flood risk (Jakarta and Bandung, Indonesia) or how flood risk is modified after a seismic event (Italy). The analysis of well documented real study cases, based on a combination between Earth Observation and in-situ data, would serve as basis the formalisation of a multi-hazard methodology, identifying gaps and research frontiers. Multi-hazard risk analysis is performed through the RASOR platform (Rapid Analysis and Spatialisation Of Risk). A scenario-driven query system allow users to simulate future scenarios based on existing and assumed conditions, to compare with historical scenarios, and to model multi-hazard risk both before and during an event (www.rasor.eu).

  13. [Profitability analysis of clinical risk management].

    Science.gov (United States)

    Banduhn, C; Schlüchtermann, J

    2013-05-01

    Medical treatment entails many risks. Increasingly, the negative impact of these risks on patients' health is revealed and corresponding cases are reported to hospital insurances. A systematic clinical risk management can reduce risks. This analysis is designed to demonstrate the financial profitability of implementing a clinical risk management. The decision analysis of a clinical risk management includes information from published articles and studies, publicly available data from the Federal Statistical Office and expert interviews and was conducted in 2 scenarios. The 2 scenarios result from a maximum and minimum value of preventable adverse events reported in Germany. The planning horizon was a 1-year ­period. The analysis was performed from a hospital's perspective. Subsequently, a threshold-analysis of the reduction of preventable adverse events as an effect of clinical risk management was executed. Furthermore, a static capital budgeting over a 5-year period was added, complemented by a risk analysis. Regarding the given assumptions, the implementation of clinical risk management would save about 53 000 € or 175 000 €, respectively, for an average hospital within the first year. Only if the reduction of preventable adverse events is as low as 5.6 or 2.8%, respectively, will the implementation of clinical risk management produce losses. According to a comprehensive risk simulation this happens in less than one out of 1 million cases. The investment in a clinical risk management, based on a 5-year period and an interest rate of 5%, has an annually pay off of 81 000 € or 211 000 €, respectively. The implementation of clinical risk management in a hospital pays off within the first year. In the subsequent years the surplus is even higher due to the elimination of implementation costs. © Georg Thieme Verlag KG Stuttgart · New York.

  14. Collision Risk Analysis for HSC

    DEFF Research Database (Denmark)

    Urban, Jesper; Pedersen, Preben Terndrup; Simonsen, Bo Cerup

    1999-01-01

    High Speed Craft (HSC) have a risk profile, which is distinctly different from conventional ferries. Due to different hull building material, structural layout, compartmentation and operation, both frequency and consequences of collision and grounding accidents must be expected to be different from...... conventional ships. To reach a documented level of safety, it is therefore not possible directly to transfer experience with conventional ships. The purpose of this paper is to present new rational scientific tools to assess and quantify the collision risk associated with HSC transportation. The paper...

  15. Nutrition, sensory evaluation, and performance analysis of hydrogenated frying oils.

    Science.gov (United States)

    Hack, Danielle M; Bordi, Peter L; Hessert, S William

    2009-12-01

    The Food and Drug Administration now requires labeling of trans fats on nutrition labels, a decision that has created a push to reformulate deep-fat frying oils. Prior to the passage of this law, frying oils contained trans fats because trans fats made the oils more stable and thus allowing for longer frying usage. In the present study, oil performance, sensory evaluation and nutritional analysis was conducted on trans fat-free oils through a 10-day degradation process using French fries to break down the oil. The goal of the study was to test oil stability and nutrition analysis and to learn consumer preference between trans fat and trans fat-free oils. Sensory evaluation indicated a preference for fries composed from trans fat-free oil mixtures. The most stable oils were also combination oils. Based on these findings, industry representatives considering using the trans fat-free frying oils should consider using blended oils instead, which met customers' taste preference and minimized oil rancidity and usage.

  16. Isotopic disproportionation during hydrogen isotopic analysis of nitrogen-bearing organic compounds

    Science.gov (United States)

    Nair, Sreejesh; Geilmann, Heike; Coplen, Tyler B.; Qi, Haiping; Gehre, Matthias; Schimmelmann, Arndt; Brand, Willi A.

    2015-01-01

    Rationale High-precision hydrogen isotope ratio analysis of nitrogen-bearing organic materials using high-temperature conversion (HTC) techniques has proven troublesome in the past. Formation of reaction products other than molecular hydrogen (H2) has been suspected as a possible cause of incomplete H2 yield and hydrogen isotopic fractionation. Methods The classical HTC reactor setup and a modified version including elemental chromium, both operated at temperatures in excess of 1400 °C, have been compared using a selection of nitrogen-bearing organic compounds, including caffeine. A focus of the experiments was to avoid or suppress hydrogen cyanide (HCN) formation and to reach quantitative H2 yields. The technique also was optimized to provide acceptable sample throughput. Results The classical HTC reaction of a number of selected compounds exhibited H2 yields from 60 to 90 %. Yields close to 100 % were measured for the experiments with the chromium-enhanced reactor. The δ2H values also were substantially different between the two types of experiments. For the majority of the compounds studied, a highly significant relationship was observed between the amount of missing H2and the number of nitrogen atoms in the molecules, suggesting the pyrolytic formation of HCN as a byproduct. A similar linear relationship was found between the amount of missing H2 and the observed hydrogen isotopic result, reflecting isotopic fractionation. Conclusions The classical HTC technique to produce H2 from organic materials using high temperatures in the presence of glassy carbon is not suitable for nitrogen-bearing compounds. Adding chromium to the reaction zone improves the yield to 100 % in most cases. The initial formation of HCN is accompanied by a strong hydrogen isotope effect, with the observed hydrogen isotope results on H2 being substantially shifted to more negative δ2H values. The reaction can be understood as an initial disproportionation leading to H2 and HCN

  17. Risk analysis of computer system designs

    Science.gov (United States)

    Vallone, A.

    1981-01-01

    Adverse events during implementation can affect final capabilities, schedule and cost of a computer system even though the system was accurately designed and evaluated. Risk analysis enables the manager to forecast the impact of those events and to timely ask for design revisions or contingency plans before making any decision. This paper presents a structured procedure for an effective risk analysis. The procedure identifies the required activities, separates subjective assessments from objective evaluations, and defines a risk measure to determine the analysis results. The procedure is consistent with the system design evaluation and enables a meaningful comparison among alternative designs.

  18. RISK ANALYSIS, ANALYSIS OF VARIANCE: GETTING MORE FROM OUR DATA

    Science.gov (United States)

    Analysis of variance (ANOVA) and regression are common statistical techniques used to analyze agronomic experimental data and determine significant differences among yields due to treatments or other experimental factors. Risk analysis provides an alternate and complimentary examination of the same...

  19. Rate equation analysis of hydrogen uptake on Si (100) surfaces

    Science.gov (United States)

    Inanaga, S.; Rahman, F.; Khanom, F.; Namiki, A.

    2005-09-01

    We have studied the uptake process of H on Si (100) surfaces by means of rate equation analysis. Flowers' quasiequilibrium model for adsorption and desorption of H [M. C. Flowers, N. B. H. Jonathan, A. Morris, and S. Wright, Surf. Sci. 396, 227 (1998)] is extended so that in addition to the H abstraction (ABS) and β2-channel thermal desorption (TD) the proposed rate equation further includes the adsorption-induced desorption (AID) and β1-TD. The validity of the model is tested by the experiments of ABS and AID rates in the reaction system H+D/Si (100). Consequently, we find it can well reproduce the experimental results, validating the proposed model. We find the AID rate curve as a function of surface temperature Ts exhibits a clear anti-correlation with the bulk dangling bond density versus Ts curve reported in the plasma-enhanced chemical vapor deposition (CVD) for amorphous Si films. The significance of the H chemistry in plasma-enhanced CVD is discussed.

  20. Novel technique for coal pyrolysis and hydrogenation product analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pfefferle, L.D.; Boyle, J.

    1993-03-15

    A microjet reactor coupled to a VUV photoionization time-of-flight mass spectrometer has been used to obtain species measurements during high temperature pyrolysis and oxidation of a wide range of hydrocarbon compounds ranging from allene and acetylene to cyclohexane, benzene and toluene. Initial work focused on calibration of the technique, optimization of ion collection and detection and characterization of limitations. Using the optimized technique with 118 nm photoionization, intermediate species profiles were obtained for analysis of the hydrocarbon pyrolysis and oxidation mechanisms. The soft'' ionization, yielding predominantly molecular ions, allowed the study of reaction pathways in these high temperature systems where both sampling and detection challenges are severe. Work has focused on the pyrolysis and oxidative pyrolysis of aliphatic and aromatic hydrocarbon mixtures representative of coal pyrolysis and hydropyrolysis products. The detailed mass spectra obtained during pyrolysis and oxidation of hydrocarbon mixtures is especially important because of the complex nature of the product mixture even at short residence times and low primary reactant conversions. The combustion community has advanced detailed modeling of pyrolysis and oxidation to the C4 hydrocarbon level but in general above that size uncertainties in rate constant and thermodynamic data do not allow us to a priori predict products from mixed hydrocarbon pyrolyses using a detailed chemistry model. For pyrolysis of mixtures of coal-derived liquid fractions with a large range of compound structures and molecular weights in the hundreds of amu the modeling challenge is severe. Lumped models are possible from stable product data.

  1. Safety analysis, risk assessment, and risk acceptance criteria

    Energy Technology Data Exchange (ETDEWEB)

    Jamali, K. [Dept. of Energy, Germantown, MD (United States). Core Technical Support and Facility Transition; Stack, D.W.; Sullivan, L.H.; Sanzo, D.L. [Los Alamos National Lab., NM (United States)

    1997-08-01

    This paper discusses a number of topics that relate safety analysis as documented in the Department of Energy (DOE) safety analysis reports (SARs), probabilistic risk assessments (PRA) as characterized primarily in the context of the techniques that have assumed some level of formality in commercial nuclear power plant applications, and risk acceptance criteria as an outgrowth of PRA applications. DOE SARs of interest are those that are prepared for DOE facilities under DOE Order 5480.23 and the implementing guidance in DOE STD-3009-94. It must be noted that the primary area of application for DOE STD-3009 is existing DOE facilities and that certain modifications of the STD-3009 approach are necessary in SARs for new facilities. Moreover, it is the hazard analysis (HA) and accident analysis (AA) portions of these SARs that are relevant to the present discussions. Although PRAs can be qualitative in nature, PRA as used in this paper refers more generally to all quantitative risk assessments and their underlying methods. HA as used in this paper refers more generally to all qualitative risk assessments and their underlying methods that have been in use in hazardous facilities other than nuclear power plants. This discussion includes both quantitative and qualitative risk assessment methods. PRA has been used, improved, developed, and refined since the Reactor Safety Study (WASH-1400) was published in 1975 by the Nuclear Regulatory Commission (NRC). Much debate has ensued since WASH-1400 on exactly what the role of PRA should be in plant design, reactor licensing, `ensuring` plant and process safety, and a large number of other decisions that must be made for potentially hazardous activities. Of particular interest in this area is whether the risks quantified using PRA should be compared with numerical risk acceptance criteria (RACs) to determine whether a facility is `safe.` Use of RACs requires quantitative estimates of consequence frequency and magnitude.

  2. Transcriptional Profiling of Hydrogen Production Metabolism of Rhodobacter capsulatus under Temperature Stress by Microarray Analysis

    Directory of Open Access Journals (Sweden)

    Muazzez Gürgan

    2015-06-01

    Full Text Available Biohydrogen is a clean and renewable form of hydrogen, which can be produced by photosynthetic bacteria in outdoor large-scale photobioreactors using sunlight. In this study, the transcriptional response of Rhodobacter capsulatus to cold (4 °C and heat (42 °C stress was studied using microarrays. Bacteria were grown in 30/2 acetate/glutamate medium at 30 °C for 48 h under continuous illumination. Then, cold and heat stresses were applied for two and six hours. Growth and hydrogen production were impaired under both stress conditions. Microarray chips for R. capsulatus were custom designed by Affymetrix (GeneChip®. TR_RCH2a520699F. The numbers of significantly changed genes were 328 and 293 out of 3685 genes under cold and heat stress, respectively. Our results indicate that temperature stress greatly affects the hydrogen production metabolisms of R. capsulatus. Specifically, the expression of genes that participate in nitrogen metabolism, photosynthesis and the electron transport system were induced by cold stress, while decreased by heat stress. Heat stress also resulted in down regulation of genes related to cell envelope, transporter and binding proteins. Transcriptome analysis and physiological results were consistent with each other. The results presented here may aid clarification of the genetic mechanisms for hydrogen production in purple non-sulfur (PNS bacteria under temperature stress.

  3. Asbestos Workshop: Sampling, Analysis, and Risk Assessment

    Science.gov (United States)

    2012-03-01

    1EMDQ March 2012 ASBESTOS WORKSHOP: SAMPLING, ANALYSIS, AND RISK ASSESSMENT Paul Black, PhD, Neptune and Company Ralph Perona, DABT, Neptune and...NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Neptune and Company, Inc,1435 Garrison Street, Suite 110,Denver,CO...8-98) Prescribed by ANSI Std Z39-18 2 Presentation Objective Provide an overview of asbestos-related risk assessment: • Focus on risk from

  4. Methods of Risk Analysis of Telematic Objects

    Directory of Open Access Journals (Sweden)

    Jozef Stefanak

    2008-01-01

    Full Text Available The paper focuses on basic description of the tunnel as a telematic object and its architecture. Conventional methods of risk analysis of telematic objects are introduced in relation to their safety. New approaches of risk quantification are shown in connection to existing legislation and directives of European Commission.

  5. Sensitivity Analysis of Fatigue Crack Growth Model for API Steels in Gaseous Hydrogen.

    Science.gov (United States)

    Amaro, Robert L; Rustagi, Neha; Drexler, Elizabeth S; Slifka, Andrew J

    2014-01-01

    A model to predict fatigue crack growth of API pipeline steels in high pressure gaseous hydrogen has been developed and is presented elsewhere. The model currently has several parameters that must be calibrated for each pipeline steel of interest. This work provides a sensitivity analysis of the model parameters in order to provide (a) insight to the underlying mathematical and mechanistic aspects of the model, and (b) guidance for model calibration of other API steels.

  6. Risk and safety analysis of nuclear systems

    National Research Council Canada - National Science Library

    Lee, John C; McCormick, Norman J

    2011-01-01

    .... The first half of the book covers the principles of risk analysis, the techniques used to develop and update a reliability data base, the reliability of multi-component systems, Markov methods used...

  7. Guidelines for wildlife disease risk analysis

    National Research Council Canada - National Science Library

    2014-01-01

    Provides an overview of science-based processes and tools for wildlife disease risk analysis and their application to contemporary issues such as human-wildlife interactions, domestic animal-wildlife...

  8. Comprehensive risk analysis for structure type selection.

    Science.gov (United States)

    2010-04-01

    Optimization of bridge selection and design traditionally has been sought in terms of the finished structure. This study presents a : more comprehensive risk-based analysis that includes user costs and accidents during the construction phase. Costs f...

  9. Effect of culture conditions on producing and uptake hydrogen flux of biohydrogen fermentation by metabolic flux analysis method.

    Science.gov (United States)

    Niu, Kun; Zhang, Xu; Tan, Wen-Song; Zhu, Ming-Long

    2011-08-01

    In this work, metabolic flux analysis (MFA) method was used to estimate the effects of the culture conditions on both the producing and uptake hydrogen flux inside the cell of Klebsiella pneumoniae ECU-15. The results indicated that higher temperature could reduce the amount of the uptake hydrogen and enhance the hydrogen production from the NADH pathway. Moreover, both the producing hydrogen flux from formate and the uptake hydrogen flux were attained to the maximum at pH 7.0-7.5. The producing hydrogen flux was higher at 5g/L initial glucose than that of the other concentrations, and the uptake hydrogen flux showed the minimum value under the same condition. The apparent hydrogen generation was caused by the combined action of producing hydrogenase, uptake hydrogenase and bidirectional hydrogenase. These results were helpful to deeply understand the mechanism of the biohydrogen evolving process and establish the suitable molecular strategies for improving hydrogen production. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Quantitative analysis of hydrogen in SiO2/SiN/SiO2 stacks using atom probe tomography

    Directory of Open Access Journals (Sweden)

    Yorinobu Kunimune

    2016-04-01

    Full Text Available We have demonstrated that it is possible to reproducibly quantify hydrogen concentration in the SiN layer of a SiO2/SiN/SiO2 (ONO stack structure using ultraviolet laser-assisted atom probe tomography (APT. The concentration of hydrogen atoms detected using APT increased gradually during the analysis, which could be explained by the effect of hydrogen adsorption from residual gas in the vacuum chamber onto the specimen surface. The amount of adsorbed hydrogen in the SiN layer was estimated by analyzing another SiN layer with an extremely low hydrogen concentration (<0.2 at. %. Thus, by subtracting the concentration of adsorbed hydrogen, the actual hydrogen concentration in the SiN layer was quantified as approximately 1.0 at. %. This result was consistent with that obtained by elastic recoil detection analysis (ERDA, which confirmed the accuracy of the APT quantification. The present results indicate that APT enables the imaging of the three-dimensional distribution of hydrogen atoms in actual devices at a sub-nanometer scale.

  11. Gender Analysis of Risk in Innovation System

    DEFF Research Database (Denmark)

    Ayinde, Ope; Muchie, Mammo; Abaniyan, E. O.

    2011-01-01

    the new maize variety. The analytical tools used include descriptive statistics, regression model; risk utility functions and risk parameter analysis. The result showed that invasion by animals, disease and pest, lack of access to credit wind and price fluctuation were the major risk facing the maize......This study analyzed risk by gender in innovation in Kwara state, Nigeria, using downy mildew resistant maize production as case study. The study employed primary and secondary data. The primary data were collected from well-structured questionnaires administered to both male and female producing...... producers in the area in the usage of the new innovation. The study also revealed that male producers were willing to take risk in the new maize variety production than the female, while the females were more indifferent to the risk involved in the new maize production variety than males. None...

  12. Intentional risk management through complex networks analysis

    CERN Document Server

    Chapela, Victor; Moral, Santiago; Romance, Miguel

    2015-01-01

    This book combines game theory and complex networks to examine intentional technological risk through modeling. As information security risks are in constant evolution,  the methodologies and tools to manage them must evolve to an ever-changing environment. A formal global methodology is explained  in this book, which is able to analyze risks in cyber security based on complex network models and ideas extracted from the Nash equilibrium. A risk management methodology for IT critical infrastructures is introduced which provides guidance and analysis on decision making models and real situations. This model manages the risk of succumbing to a digital attack and assesses an attack from the following three variables: income obtained, expense needed to carry out an attack, and the potential consequences for an attack. Graduate students and researchers interested in cyber security, complex network applications and intentional risk will find this book useful as it is filled with a number of models, methodologies a...

  13. Uncertainties in risk assessment of hydrogen discharges from pressurized storage vessels at low temperatures

    DEFF Research Database (Denmark)

    Markert, Frank; Melideo, D.; Baraldi, D.

    2013-01-01

    20K) e.g. the cryogenic compressed gas storage covers pressures up to 35 MPa and temperatures between 33K and 338 K. Accurate calculations of high pressure releases require real gas EOS. This paper compares a number of EOS to predict hydrogen properties typical in different storage types. The vessel...

  14. Why hydrogen; Pourquoi l'hydrogene?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-02-01

    The energy consumption increase and the associated environmental risks, led to develop new energy sources. The authors present the potentialities of the hydrogen in this context of energy supply safety. They detail the today market and the perspectives, the energy sources for the hydrogen production (fossils, nuclear and renewable), the hydrogen transport, storage, distribution and conversion, the application domains, the associated risks. (A.L.B.)

  15. Development of hydrogen sensors based on fiber Bragg grating with a palladium foil for online dissolved gas analysis in transformers

    Science.gov (United States)

    Fisser, Maximilian; Badcock, Rodney A.; Teal, Paul D.; Swanson, Adam; Hunze, Arvid

    2017-06-01

    Hydrogen evolution, identified by dissolved gas analysis (DGA), is commonly used for fault detection in oil immersed electrical power equipment. Palladium (Pd) is often used as a sensing material due to its high hydrogen absorption capacity and related change in physical properties. Hydrogen is absorbed by Pd causing an expansion of the lattice. The solubility, and therefore lattice expansion, increases with increasing partial pressure of hydrogen and decreasing temperature. As long as a phase change is avoided the expansion is reversible and can be utilized to transfer strain into a sensing element. Fiber Bragg gratings (FBG) are a well-established optical fiber sensor (OFS), mainly used for temperature and strain sensing. A safe, inexpensive, reliable and precise hydrogen sensor can be constructed using an FBG strain sensor to transduce the volumetric expansion of Pd due to hydrogen absorption. This paper reports on the development, and evaluation, of an FBG gas sensing OFS and long term measurements of dissolved hydrogen in transformer mineral oil. We investigate the effects of Pd foil cross-section and strain transfer between foil and fiber on the sensitivity of the OFS. Two types of Pd metal sensors were manufactured using modified Pd foil with 20 and 100 μm thickness. The sensors were tested in transformer oil at 90°C and a hydrogen concentration range from 20- 3200 ppm.

  16. Risk Analysis at Work in Manufacturing Organization

    Directory of Open Access Journals (Sweden)

    Maroš Korenko

    2015-01-01

    Full Text Available Risk is virtually present everywhere around us. Nowadays, there is an increasing focus on safety at work; therefore, the organizations that want to be successful in the market try to eliminate risk factors to a minimum to avoid or prevent the health hazard of employees, damages to property or the environment. The work is focused on the risk assessment of a selected device, which is the most risky workplace according to the organization where the research was conducted. In the practical part, we became familiar with the equipment for welding and a thorough analysis of the current state of safety by a complex method was done. Consequently, corrective actions to reduce risk to an acceptable level were proposed. After that, we reassessed the risks of complex method, and the point method was used to verify the effectiveness of proposed remedial measures.

  17. HACCP and risk analysis in global

    Directory of Open Access Journals (Sweden)

    Uhlenhopps Eldon K.

    2002-01-01

    Full Text Available Recent public concern regarding food safety, and the implementation of Global regulations and agreements on trade, have given rise to questions regarding the veterinarian’s role and expertise in formally assessing and mitigating these risk. The objective of this work is to demonstrate latest knowledge on Risk Analysis as a process, to review HACCP with regard to food safety and defense against introduction of infectious agents.

  18. Technical Analysis of Projects Being Funded by the DOE Hydrogen Program

    Energy Technology Data Exchange (ETDEWEB)

    Edward G. Skolnik

    2006-02-10

    In July 2000, Energetics began a project in which we performed site-visit based technical analyses or evaluations on hydrogen R&D projects for the purpose of providing in-depth information on the status and accomplishments of these projects to the public, and especially to hydrogen stakeholders. Over a three year period, 32 site-visit analyses were performed. In addition two concepts gleaned from the site visits became subjects of in depth techno-economic analyses. Finally, Energetics produced a compilation document that contains each site-visit analysis that we have performed, starting in 1996 on other contracts through the end of Year One of the current project (July 2001). This included 21 projects evaluated on previous contracts, and 10 additional ones from Year One. Reports on projects visited in Years One and Two were included in their respective Annual Reports. The Year Two Report also includes the two In-depth Analyses and the Compilation document. Reports in Year three began an attempt to perform reviews more geared to hydrogen safety. This Final Report contains a summary of the overall project, all of the 32 site-visit analyses and the two In-depth Analyses.

  19. Introduction of hydrogen in the Norwegian energy system. NorWays - Regional model analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Eva; Fidje, Audun; Espegren, Kari Aamodt

    2008-12-15

    The overall aim of the NorWays project has been to provide decision support for the introduction of hydrogen as an energy carrier in the Norwegian energy system. The NorWays project is a research project funded by the Research Council of Norway. An important task has been to develop alternative scenarios and identifying market segments and regions of the Norwegian energy system where hydrogen may play a significant role. The main scenarios in the project have been: Reference: Based on the assumptions of World Energy Outlook with no new transport technologies; HyWays: Basic assumptions with technology costs (H{sub 2}) based on results from the HyWays project; No tax: No taxes on transport energy ('revenue neutral'); CO{sub 2} reduction: Reduced CO{sub 2} emissions by 75% in 2050. Three regional models have been developed and used to analyse the introduction of hydrogen as energy carrier in competition with other alternatives such as natural gas, electricity, district heating and bio fuels.The focus of the analysis has been on the transportation sector. (Author)

  20. System Evaluation and Life-Cycle Cost Analysis of a Commercial-Scale High-Temperature Electrolysis Hydrogen Production Plant

    Energy Technology Data Exchange (ETDEWEB)

    Edwin A. Harvego; James E. O' Brien; Michael G. McKellar

    2012-11-01

    Results of a system evaluation and lifecycle cost analysis are presented for a commercial-scale high-temperature electrolysis (HTE) central hydrogen production plant. The plant design relies on grid electricity to power the electrolysis process and system components, and industrial natural gas to provide process heat. The HYSYS process analysis software was used to evaluate the reference central plant design capable of producing 50,000 kg/day of hydrogen. The HYSYS software performs mass and energy balances across all components to allow optimization of the design using a detailed process flow sheet and realistic operating conditions specified by the analyst. The lifecycle cost analysis was performed using the H2A analysis methodology developed by the Department of Energy (DOE) Hydrogen Program. This methodology utilizes Microsoft Excel spreadsheet analysis tools that require detailed plant performance information (obtained from HYSYS), along with financial and cost information to calculate lifecycle costs. The results of the lifecycle analyses indicate that for a 10% internal rate of return, a large central commercial-scale hydrogen production plant can produce 50,000 kg/day of hydrogen at an average cost of $2.68/kg. When the cost of carbon sequestration is taken into account, the average cost of hydrogen production increases by $0.40/kg to $3.08/kg.

  1. Economic and technical analysis of distributed utility benefits for hydrogen refueling stations

    Energy Technology Data Exchange (ETDEWEB)

    Iannucci, J.J.; Eyer, J.M.; Horgan, S.A. [Distributed Utility Associates, Livermore, CA (United States); Schoenung, S.M. [Longitude 122 West, Inc., Menlo Park, CA (United States)

    1998-08-01

    This paper discusses the potential economic benefits of operating hydrogen refueling stations to supplying pressurized hydrogen for vehicles, and supplying distributed utility generation, transmission and distribution peaking needs to the utility. The study determined under what circumstances using a hydrogen-fueled generator as a distributed utility generation source, co-located with the hydrogen refueling station components (electrolyzer and storage), would result in cost savings to the station owner, and hence lower hydrogen production costs.

  2. Risk Assessment and Integration Team (RAIT) Portfolio Risk Analysis Strategy

    Science.gov (United States)

    Edwards, Michelle

    2010-01-01

    Impact at management level: Qualitative assessment of risk criticality in conjunction with risk consequence, likelihood, and severity enable development of an "investment policy" towards managing a portfolio of risks. Impact at research level: Quantitative risk assessments enable researchers to develop risk mitigation strategies with meaningful risk reduction results. Quantitative assessment approach provides useful risk mitigation information.

  3. Computational fluid dynamics analysis of SSME phase 2 and phase 2+ preburner injector element hydrogen flow paths

    Science.gov (United States)

    Ruf, Joseph H.

    1992-01-01

    Phase 2+ Space Shuttle Main Engine powerheads, E0209 and E0215 degraded their main combustion chamber (MCC) liners at a faster rate than is normal for phase 2 powerheads. One possible cause of the accelerated degradation was a reduction of coolant flow through the MCC. Hardware changes were made to the preburner fuel leg which may have reduced the resistance and, therefore, pulled some of the hydrogen from the MCC coolant leg. A computational fluid dynamics (CFD) analysis was performed to determine hydrogen flow path resistances of the phase 2+ fuel preburner injector elements relative to the phase 2 element. FDNS was implemented on axisymmetric grids with the hydrogen assumed to be incompressible. The analysis was performed in two steps: the first isolated the effect of the different inlet areas and the second modeled the entire injector element hydrogen flow path.

  4. Risk analysis for critical asset protection.

    Science.gov (United States)

    McGill, William L; Ayyub, Bilal M; Kaminskiy, Mark

    2007-10-01

    This article proposes a quantitative risk assessment and management framework that supports strategic asset-level resource allocation decision making for critical infrastructure and key resource protection. The proposed framework consists of five phases: scenario identification, consequence and criticality assessment, security vulnerability assessment, threat likelihood assessment, and benefit-cost analysis. Key innovations in this methodology include its initial focus on fundamental asset characteristics to generate an exhaustive set of plausible threat scenarios based on a target susceptibility matrix (which we refer to as asset-driven analysis) and an approach to threat likelihood assessment that captures adversary tendencies to shift their preferences in response to security investments based on the expected utilities of alternative attack profiles assessed from the adversary perspective. A notional example is provided to demonstrate an application of the proposed framework. Extensions of this model to support strategic portfolio-level analysis and tactical risk analysis are suggested.

  5. Safety Issues with Hydrogen as a Vehicle Fuel

    Energy Technology Data Exchange (ETDEWEB)

    L. C. Cadwallader; J. S. Herring

    1999-09-01

    This report is an initial effort to identify and evaluate safety issues associated with the use of hydrogen as a vehicle fuel in automobiles. Several forms of hydrogen have been considered: gas, liquid, slush, and hydrides. The safety issues have been discussed, beginning with properties of hydrogen and the phenomenology of hydrogen combustion. Safety-related operating experiences with hydrogen vehicles have been summarized to identify concerns that must be addressed in future design activities and to support probabilistic risk assessment. Also, applicable codes, standards, and regulations pertaining to hydrogen usage and refueling have been identified and are briefly discussed. This report serves as a safety foundation for any future hydrogen safety work, such as a safety analysis or a probabilistic risk assessment.

  6. Safety Issues with Hydrogen as a Vehicle Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Cadwallader, Lee Charles; Herring, James Stephen

    1999-10-01

    This report is an initial effort to identify and evaluate safety issues associated with the use of hydrogen as a vehicle fuel in automobiles. Several forms of hydrogen have been considered: gas, liquid, slush, and hydrides. The safety issues have been discussed, beginning with properties of hydrogen and the phenomenology of hydrogen combustion. Safety-related operating experiences with hydrogen vehicles have been summarized to identify concerns that must be addressed in future design activities and to support probabilistic risk assessment. Also, applicable codes, standards, and regulations pertaining to hydrogen usage and refueling have been identified and are briefly discussed. This report serves as a safety foundation for any future hydrogen safety work, such as a safety analysis or a probabilistic risk assessment.

  7. An economic analysis of hydrogen production from wind electricity for transport purposes; Une analyse economique de la production d'hydrogene a partir d'electricite eolienne pour des usages transport

    Energy Technology Data Exchange (ETDEWEB)

    Menanteau, P. [Grenoble-1 Univ., LEPII, CNRS, 38 (France); Quemere, M.M. [Electricite de France (EDF-RD), Recherche et Developpement, 78 - Chatou (France); Le Duigou, A. [CEA Saclay, Coordinateur du projet HyFrance3, 91 - Gif-sur-Yvette (France); Le Bastard, S. [Electricite de France (EDF), stagiaire, 92 - Clamart (France)

    2010-09-15

    Wind electricity is often considered as a particularly promising option for hydrogen production from renewable energies, but the economics of such production remain generally rather unclear. The purpose of this paper is to explain such conditions by examining the parameters necessary for the production of hydrogen. The analysis undertaken here for transportation uses shows great variability in hydrogen production costs depending on considered demand applications, with a clear advantage for those systems that severely limit the use of storage facilities. (authors)

  8. Thermodynamic analysis on the CO2 conversion processes of methane dry reforming for hydrogen production and CO2 hydrogenation to dimethyl ether

    Science.gov (United States)

    He, Xinyi; Liu, Liping

    2017-12-01

    Based on the principle of Gibbs free energy minimization, the thermodynamic analysis on the CO2 conversion processes of dry reforming of methane for H2 and CO2 hydrogenation to dimethyl ether was carried out. The composition of the reaction system was determined on the basis of reaction mechanism. The effects of reaction temperature, pressure and raw material composition on the equilibrium conversion and the selectivity of products were analyzed. The results show that high temperature, low pressure, CO2/CH4 molar ratio of 1.0-1.5 and appropriate amount of oxygen are beneficial to the dry reforming of methane. For CO2 hydrogenation to dimethyl ether, low temperature, high pressure, the appropriate H2/CO2 and the proper CO addition in feed are favorable. The calculated results are compared with the relevant studies, indicating that industrial catalytic technology needs further improvement.

  9. Risk analysis to optimise safety during basic tunnel design

    NARCIS (Netherlands)

    Molag, M.; Jansen, C.M.A.

    1998-01-01

    The risk analysis to select the preferred basic tunnel design for the tunnels in the High Speed Train Link South from Amsterdam to Antwerp is described. The risk analysis has been split up in two stages: a broad qualitative risk analysis and a quantitative risk analysis. The results of the

  10. Release of hydrogen sulfide by asteroid impacts in Black Sea and risks for inland human population.

    Science.gov (United States)

    Badescu, Viorel

    2007-10-01

    The hydrogen sulfide rich waters of the Black Sea pose a potential danger for the surrounding land regions. The impact of an asteroid may cause a catastrophic poisonous gas release in the atmosphere. Some effects of this last phenomenon on the Eastern Black Sea coastal regions are evaluated in this article. Two simple models are proposed to describe the generation of the H(2)S cloud. The initial diameter of the cloud depends on asteroid size. The initial thickness of the cloud depends, in addition, on sea depth at impact location. The wind speed plays an important role in H(2)S cloud dynamics. At 10 m/s wind-speed the cloud margins may be seen at about 150 km from impact location in about 3.2 h. The maximum distance traveled by the hydrogen sulfide cloud increases by increasing the asteroid size and wind speed. The influence of the impact position on the distance traveled by hydrogen sulfide clouds is rather weak, as far as the seawater depth does not change significantly. Two values are considered when referring to the effect of hydrogen sulfide concentrations on humans: the lower concentration limit of 19.88 ppm (which corresponds to fatigue, loss of appetite, headache, irritability, poor memory, dizziness) and the upper concentration limit of 497 ppm (which corresponds to death after single exposures). The land surface area covered by the H(2)S cloud generated by a 1000 m size asteroid during the run-in ranges between about 6080 and 11,520 km(2). This may affect between 145,000 and 276,000 people. When a 250 m size asteroid is considered, the covered land surface area ranges between about 840 and 1,890 km(2) and between 20,000 and 45,000 people may be affected. In case of a 70 m size asteroid, the cloud covers up to 105 km(2) of land during the run-in. This may affect about 2500 people. These are moderate estimates. They do not include the urban population and may be 10 times underestimated for some particular wind directions. General recommendations to diminish

  11. Analysis Method for Licensing Application of Passive Autocatalytic Recombiner System as a Hydrogen Mitigation System of OPR-1000

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Changhyun; Sung, Jejoong; Ha, Sangjun [Korea Hydro and Nuclear Power Co. Ltd., Daejeon (Korea, Republic of); Yeo, Inseon [KEPCO Engineering and Construction Co. Ltd., Yongin (Korea, Republic of)

    2014-05-15

    As a result, for some plants, dual hydrogen mitigation systems are prepared with a combination of PARs and igniters that each system has a 100% of full capacity for hydrogen control for postulated severe accident conditions. In the original design of OPR-1000, hydrogen mitigation systems consist of a thermal recombiner and twenty glow-type igniters, which are used for design basis accident and severe accident, respectively. This paper presents an analysis method for licensing application in Korea to determine the capacity and locations of PARs for the design of a hydrogen mitigation system with PAR. A licensed analysis method of OPR-1000 has been presented to determine the capacity and locations of PAR for the design of a hydrogen mitigation system with PAR. A lumped parameter code of MAAP 4.0.6+ has been adopted to simulate various severe accident scenarios with a 26 multi-compartment containment model. Hydrogen generations were analysed and required capacity and locations of PAR were determined for six accident scenarios selected from a combination of probabilistic and deterministic considerations. A total of twenty-four PARs in the containment dome, steam generator rooms, annulus and adjacent areas was designed and the adequacy of this system has been confirmed through detailed analyses including sensitivity analyses with/without operations of safety systems such as containment heat removal systems, reactor coolant depressurization system and safety injection by accumulator, etc. Through the assessment on the possibility of global FA and DDT, it has been concluded that new PAR system with twenty-four recombiners can remove hydrogen effectively in the containment atmosphere and prevent from global FA and DDT. Further works are required in the future to develop a well-balanced analysis methodology with a combination of lumped and CFD tools focusing on the optimum locations of recombiners and local hydrogen behaviour in containment compartments.

  12. Supplemental Hazard Analysis and Risk Assessment - Hydrotreater

    Energy Technology Data Exchange (ETDEWEB)

    Lowry, Peter P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wagner, Katie A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-01

    A supplemental hazard analysis was conducted and quantitative risk assessment performed in response to an independent review comment received by the Pacific Northwest National Laboratory (PNNL) from the U.S. Department of Energy Pacific Northwest Field Office (PNSO) against the Hydrotreater/Distillation Column Hazard Analysis Report issued in April 2013. The supplemental analysis used the hazardous conditions documented by the previous April 2013 report as a basis. The conditions were screened and grouped for the purpose of identifying whether additional prudent, practical hazard controls could be identified, using a quantitative risk evaluation to assess the adequacy of the controls and establish a lower level of concern for the likelihood of potential serious accidents. Calculations were performed to support conclusions where necessary.

  13. An innovative molybdenum column liner for oxygen and hydrogen stable isotope analysis by pyrolysis.

    Science.gov (United States)

    Stuart-Williams, Hilary; Wong, S Chin; Farquhar, Graham D; Keitel, Claudia; Clayton, Stephen

    2008-04-01

    The most widely used method for pyrolysing samples for hydrogen or oxygen isotopic analysis involves heating them to greater than 1300 degrees C in a helium stream passed through a glassy carbon tube in an alumina casing. There are a number of difficulties with this. Glassy carbon tubes are expensive and interaction between the carbon tube and the outer casing produces unwanted carbon monoxide by reduction of the alumina at high temperatures. The latter effect is overwhelming if temperatures of 1400 degrees C or greater are used for pyrolysis. We experimented with lining alumina casings with pure molybdenum sheet. It is relatively cheap, conforms well to the interior of the reactor tube (to avoid carrier and sample bypassing of the carbon pack), resists high temperatures and neither oxidises excessively nor absorbs the gases. The main disadvantages are that silver sample cups must be used and that the molybdenum degrades over time by formation of the carbide. We can maintain sharp peaks, high precision and good accuracy over more than 700 solid samples for both hydrogen and oxygen. The reactors last longer for water injections. The molybdenum in the columns does not contribute greatly to memory effects. The precision of analysis is dependent on other factors as well as the pyrolysis column, but for oxygen we typically achieve approximately <0.2 per thousand (sucrose), <0.25 per thousand (water) and <0.25 per thousand (leaf), sometimes using only a linear correction of drift, after dividing the run into 1 to 3 segments.

  14. Template electrodeposition of high-performance copper oxide nanosensors for electrochemical analysis of hydrogen peroxide.

    Science.gov (United States)

    Rajendra Kumar Reddy, Gajjala; Kumar, P Suresh

    2017-06-01

    We report on the facile electrodeposition of copper nanostructures on graphite lead substrate using anionic, cationic and non-ionic surfactant templates. Physical and electrochemical characterisation confirmed the influence of templates on the morphology and electrochemical catalytic activities of the copper electrodeposits. These electrodes were shown to be excellent electrocatalyst for the fast detection of hydrogen peroxide. A maximum sensitivity of 951.45μA/mM/cm2, LOD of 0.43μM, response time of <1s and a linearity in wide range of concentration from 1μM to 5mM were observed when sodium dodecyl sulfate was used as the template. While most of the previously reported sensors have advantages either on the facile synthesis or fast detection of analyte, our methodology enables preparation of the electrode within 120s and analysis within another 60s without any complicated procedure, thereby demonstrating one of the fastest and cost-effective method for hydrogen peroxide analysis with high sensitivity and selectivity. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Applying emulators for improved flood risk analysis

    Directory of Open Access Journals (Sweden)

    Malde Sajni

    2016-01-01

    Full Text Available Flood risk analysis often involves the integration of multivariate probability distributions over a domain defined by a consequence function. Often, solutions of this risk integral involves Monte-Carlo sampling techniques, whereby 1000’s of potential flood events are generated. It is necessary to evaluate the consequence of flooding for each sampled event. A significant computational time is required in running flood related physical process models, making it computationally impractical to evaluate flood risk using this approach. To overcome the computational challenges, this paper focusses on the Gaussian Process Emulator (GPE meta-modelling approach. Traditionally, a “look-up table” method is used when a large number of simulations from a numerical model are required. This approach typically involves simulating conditions defined across a regular matrix, and then linearly interpolating intermediate conditions. In this paper we compare a traditional “look-up table” approach to the GPE and analyse their performance in approximating SWAN wave transformation model. In both cases, selecting an appropriate training design set is important and is taken into consideration in the analysis. The analysis shows that the GPE approach requires significantly fewer SWAN runs to obtain similar (or better accuracies, enabling a substantial reduction in computation time, hence aiding the practicality of Monte-Carlo sampling techniques in advanced flood risk modelling.

  16. Terminological Ontologies for Risk and Vulnerability Analysis

    DEFF Research Database (Denmark)

    Madsen, Bodil Nistrup; Erdman Thomsen, Hanne

    2014-01-01

    Risk and vulnerability analyses are an important preliminary stage in civil contingency planning. The Danish Emergency Management Agency has developed a generic model and a set of tools that may be used in the preparedness planning, i.e. for identifying and describing society’s critical functions......, for formulating threat scenarios and for assessing consequences. Terminological ontologies, which are systems of domain specific concepts comprising concept relations and characteristics, are useful, both when describing the central concepts of risk and vulnerability analysis (meta concepts), and for further...

  17. Tsunamis: Global Exposure and Local Risk Analysis

    Science.gov (United States)

    Harbitz, C. B.; Løvholt, F.; Glimsdal, S.; Horspool, N.; Griffin, J.; Davies, G.; Frauenfelder, R.

    2014-12-01

    The 2004 Indian Ocean tsunami led to a better understanding of the likelihood of tsunami occurrence and potential tsunami inundation, and the Hyogo Framework for Action (HFA) was one direct result of this event. The United Nations International Strategy for Disaster Risk Reduction (UN-ISDR) adopted HFA in January 2005 in order to reduce disaster risk. As an instrument to compare the risk due to different natural hazards, an integrated worldwide study was implemented and published in several Global Assessment Reports (GAR) by UN-ISDR. The results of the global earthquake induced tsunami hazard and exposure analysis for a return period of 500 years are presented. Both deterministic and probabilistic methods (PTHA) are used. The resulting hazard levels for both methods are compared quantitatively for selected areas. The comparison demonstrates that the analysis is rather rough, which is expected for a study aiming at average trends on a country level across the globe. It is shown that populous Asian countries account for the largest absolute number of people living in tsunami prone areas, more than 50% of the total exposed people live in Japan. Smaller nations like Macao and the Maldives are among the most exposed by population count. Exposed nuclear power plants are limited to Japan, China, India, Taiwan, and USA. On the contrary, a local tsunami vulnerability and risk analysis applies information on population, building types, infrastructure, inundation, flow depth for a certain tsunami scenario with a corresponding return period combined with empirical data on tsunami damages and mortality. Results and validation of a GIS tsunami vulnerability and risk assessment model are presented. The GIS model is adapted for optimal use of data available for each study. Finally, the importance of including landslide sources in the tsunami analysis is also discussed.

  18. Analysis of Preparation and Properties on Shape Memory Hydrogenated Epoxy Resin Used for Asphalt Mixtures

    Directory of Open Access Journals (Sweden)

    Biao Ma

    2017-05-01

    Full Text Available The objective of this investigation is to prepare the shape memory hydrogenated epoxy resin used for asphalt mixtures (SM-HEP-AM and study its properties. The shape memory hydrogenated epoxy resin (SM-HEP is prepared using hydrogenated bisphenol A epoxy resin (AL-3040, polypropylene glycol diglycidylether diacrylate (JH-230, and isophorone diamine (IPDA. The formulations of the SM-HEP-AM are obtained by the linearly fitted method. The thermo-mechanical property, molecular structure, and shape-memory performance of the SM-HEP-AM are studied. The glass-transition temperature (Tg is determined using the differential scanning calorimeter (DSC. The results proved that the Tg level increased when the JH-230 content decreased. The thermo-mechanical property of the SM-HEP-AM is measured by dynamical mechanical analysis (DMA. The storage modulus of the SM-HEP-AM decreased with the increase in the JH-230 content. The above phenomena are attributed to the change in the JH-230 content. The shape memory performance results of the SM-HEP-AM indicate that specimen deformation can completely recover after only several minutes at Tg + 10 °C and Tg + 20 °C. The shape recovery time of the SM-HEP-AM increases with increased JH-230 content, and the change between the shape recovery time and JH-230 content gradually decreased as the temperature increased. The deformation recovery performance of asphalt mixture with and without the SM-HEP-AM (Tg = 40 °C was tested by the deformation recovery test. This was used to prove that the SM-HEP-AM helps to improve the deformation recovery performance of the asphalt mixture.

  19. Determination of hydrogen peroxide in reactor moderator solutions by flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, M.J.

    1991-12-31

    A flow injection analysis (FIA) method for the determination of hydrogen peroxide in reactor moderator water was developed and installed at the Savannah River Site (SRS) Water Quality Laboratory. The technique has an analytical range of 0.10 to 2.50 ppm (ug/mL) with a sampling rate of 40 samples per hour. The calibration curve is linear with a correlation coefficient of 0.999, and the precision is excellent with relative standard deviations at the 0.50% level for both 0.10 and 2.50 ppm standards. When the automated FIA procedure is compared to the manual method it demonstrates a twenty minute reduction in analysis time per sample, and the total liquid waste generated per sample analyzed is reduced by roughly 95 mL. 6 refs., 10 figs., 6 tabs.

  20. Determination of hydrogen peroxide in reactor moderator solutions by flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, M.J.

    1991-01-01

    A flow injection analysis (FIA) method for the determination of hydrogen peroxide in reactor moderator water was developed and installed at the Savannah River Site (SRS) Water Quality Laboratory. The technique has an analytical range of 0.10 to 2.50 ppm (ug/mL) with a sampling rate of 40 samples per hour. The calibration curve is linear with a correlation coefficient of 0.999, and the precision is excellent with relative standard deviations at the 0.50% level for both 0.10 and 2.50 ppm standards. When the automated FIA procedure is compared to the manual method it demonstrates a twenty minute reduction in analysis time per sample, and the total liquid waste generated per sample analyzed is reduced by roughly 95 mL. 6 refs., 10 figs., 6 tabs.

  1. Risk analysis for earth dam overtopping

    Directory of Open Access Journals (Sweden)

    Mo Chongxun

    2008-06-01

    Full Text Available In this paper, a model of overtopping risk under the joint effects of floods and wind waves, which is based on risk analysis theory and takes into account the uncertainties of floods, wind waves, reservoir capacity and discharge capacity of the spillway, is proposed and applied to the Chengbihe Reservoir in Baise City in Guangxi Zhuang Autonomous Region. The simulated results indicate that the flood control limiting level can be raised by 0.40 m under the condition that the reservoir overtopping risk is controlled within a mean variance of 5×10−6. As a result, the reservoir storage will increase to 16 million m3 and electrical energy generation and other functions of the reservoir will also increase greatly.

  2. Interactions between hydrogen impurities and vacancies in Mg and Al: A comparative analysis based on density functional theory

    Science.gov (United States)

    Ismer, Lars; Park, Min Sik; Janotti, Anderson; van de Walle, Chris G.

    2009-11-01

    Using first-principles methods we have studied the interactions between hydrogen impurities and vacancies in hcp Mg and fcc Al. We find that single vacancies can, in principle, host up to 9 H atoms in Mg and 10 in Al, not 12 as recently reported in the case of Al. The difference between our results and the results in previous work is attributed to a more appropriate definition of the trapping energy of hydrogen impurities in vacancies. The concentration of hydrogen-vacancy complexes depends on the amount of hydrogen dissolved in the metal, which in turn is dictated by the hydrogen chemical potential μH . We evaluated the concentration of all relevant hydrogen-vacancy complexes as a function of μH , corresponding to different H loading conditions—ranging from low pressures to high pressures of H2 gas, up to hydrogen plasma conditions. Our analysis reveals fundamental differences in the characteristics of the hydrogen-vacancy interaction between Mg and Al. In the case of Al, up to 15% of H atoms are trapped in single vacancies in the form of H-vacancy complexes even for very low values of μH . The trapping effect slows down the diffusion of H atoms in Al by more than an order of magnitude. While interactions between vacancies and single hydrogen atoms are therefore clearly important, interactions with multiple H atoms and related mechanisms (such as hydrogen-induced superabundant vacancy formation) are predicted to occur in Al only at very high values of μH . In the case of Mg, the effects of H trapping in single vacancies are negligible for low values of μH due to the relatively low formation energy of isolated interstitial H. However, vacancies containing multiple H atoms and related mechanisms such as hydrogen-induced superabundant vacancy formation are predicted to occur in Mg at much lower values of μH than in Al. We estimate that, at room temperature, the critical pressure of an H2 gas to induce hydrogen-enhanced (superabundant) vacancy formation is ˜1

  3. Quantitative Risk Analysis: Method And Process

    Directory of Open Access Journals (Sweden)

    Anass BAYAGA

    2010-03-01

    Full Text Available Recent and past studies (King III report, 2009: 73-75; Stoney 2007;Committee of Sponsoring Organisation-COSO, 2004, Bartell, 2003; Liebenberg and Hoyt, 2003; Reason, 2000; Markowitz 1957 lament that although, the introduction of quantifying risk to enhance degree of objectivity in finance for instance was quite parallel to its development in the manufacturing industry, it is not the same in Higher Education Institution (HEI. In this regard, the objective of the paper was to demonstrate the methods and process of Quantitative Risk Analysis (QRA through likelihood of occurrence of risk (phase I. This paper serves as first of a two-phased study, which sampled hundred (100 risk analysts in a University in the greater Eastern Cape Province of South Africa.The analysis of likelihood of occurrence of risk by logistic regression and percentages were conducted to investigate whether there were a significant difference or not between groups (analyst in respect of QRA.The Hosmer and Lemeshow test was non-significant with a chi-square(X2 =8.181; p = 0.300, which indicated that there was a good model fit, since the data did not significantly deviate from the model. The study concluded that to derive an overall likelihood rating that indicated the probability that a potential risk may be exercised within the construct of an associated threat environment, the following governing factors must be considered: (1 threat source motivation and capability (2 nature of the vulnerability (3 existence and effectiveness of current controls (methods and process.

  4. Technoeconomical analysis of the co-production of hydrogen energy and carbon materials

    Science.gov (United States)

    Guerra, Zuimdie

    HECAM (Hydrogen Energy and Carbon Materials) is a new energy production strategy. The main paradigm of HECAM is that energy extracted from the carbon in hydrocarbon fuels is not worth the production of carbon dioxide. The hydrocarbon fuel is heated in an oxygen free environment and it is chemically decomposed by the heat into gases (mostly hydrogen and methane), small quantities of liquid (light oil and tar), and a solid residue containing carbon and ash (char or coke). More quantities of hydrocarbons will need to be used, but less carbon dioxide will be produced. HECAM is going to compete with steam methane reforming (SMR) to produce hydrogen. HECAM with thermocatalytic decomposition of methane and efficient sensible heat recovery has a production cost per gigajoule of hydrogen about 9% higher than SMR, but will produce about half the carbon dioxide emissions that SMR produces. If HECAM with efficient sensible heat recovery is used to produce electricity in a power plant, it will have a comparable electricity production cost and carbon dioxide emissions to a natural gas combined cycle (NGCC) power plant. The byproduct coke is not a waste residue, but a valuable co-product. Uses for the byproduct coke material may be carbon sequestration, mine land restoration, additive to enhance agricultural soils, low sulfur and mercury content heating fuel for power plants, new construction materials, or carbon-base industrial materials. This study investigated the use of byproduct coke for new construction materials. HECAM concrete substitute (HCS) materials will have a comparable cost with concrete when the cost of the raw materials is $65 per metric ton of HCS produced. HECAM brick substitute (HBS) materials will have 20% higher cost per brick than clay bricks. If the HECAM byproduct coke can be formed into bricks as a product of the HECAM process, the manufacture of HBS bricks will be cheaper and may be cost competitive with clay bricks. The results of this analysis are

  5. Electrolyzer Performance Analysis of an Integrated Hydrogen Power System for Greenhouse Heating. A Case Study

    Directory of Open Access Journals (Sweden)

    Simone Pascuzzi

    2016-07-01

    Full Text Available A greenhouse containing an integrated system of photovoltaic panels, a water electrolyzer, fuel cells and a geothermal heat pump was set up to investigate suitable solutions for a power system based on solar energy and hydrogen, feeding a self-sufficient, geothermal-heated greenhouse. The electricity produced by the photovoltaic source supplies the electrolyzer; the manufactured hydrogen gas is held in a pressure tank. In these systems, the electrolyzer is a crucial component; the technical challenge is to make it work regularly despite the irregularity of the solar source. The focus of this paper is to study the performance and the real energy efficiency of the electrolyzer, analyzing its operational data collected under different operating conditions affected by the changeable solar radiant energy characterizing the site where the experimental plant was located. The analysis of the measured values allowed evaluation of its suitability for the agricultural requirements such as greenhouse heating. On the strength of the obtained result, a new layout of the battery bank has been designed and exemplified to improve the performance of the electrolyzer. The evaluations resulting from this case study may have a genuine value, therefore assisting in further studies to better understand these devices and their associated technologies.

  6. Demonstration of compound-specific isotope analysis of hydrogen isotope ratios in chlorinated ethenes.

    Science.gov (United States)

    Kuder, Tomasz; Philp, Paul

    2013-02-05

    High-temperature pyrolysis conversion of organic analytes to H(2) in hydrogen isotope ratio compound-specific isotope analysis (CSIA) is unsuitable for chlorinated compounds such as trichloroethene (TCE) and cis-1,2-dichloroethene (DCE), due to competition from HCl formation. For this reason, the information potential of hydrogen isotope ratios of chlorinated ethenes remains untapped. We present a demonstration of an alternative approach where chlorinated analytes reacted with chromium metal to form H(2) and minor amounts of HCl. The values of δ(2)H were obtained at satisfactory precision (± 10 to 15 per thousand), however the raw data required daily calibration by TCE and/or DCE standards to correct for analytical bias that varies over time. The chromium reactor has been incorporated into a purge and trap-CSIA method that is suitable for CSIA of aqueous environmental samples. A sample data set was obtained for six specimens of commercial product TCE. The resulting values of δ(2)H were between -184 and +682 ‰, which significantly widened the range of manufactured TCE δ(2)H signatures identified by past work. The implications of this finding to the assessment of TCE contamination are discussed.

  7. Hydrogen bond density and strength analysis on hydrated Rutile (110) and Cassiterite (110) surfaces

    Science.gov (United States)

    Kumar, Nitin; Kent, Paul; Bandura, Andrei; Wesolowski, David; Kubicki, James; Sofo, Jorge

    2012-02-01

    We study the dynamics of water on the surface of cassiterite (110) and rutile (110) using ab-initio molecular dynamics simulation. Water adsorbs and dissociates on these surfaces. This dynamic equilibrium is dominated by the hydrogen bond (h-bond) network at the surface. The h-bond density analysis shows that adsorbed water molecules form higher average number of h-bonds on rutile (˜2.3) as compared to the cassiterite surface (˜2.1). On the other hand, bridging oxygen atoms form higher average number of h-bonds on cassiterite (˜1.4) than rutile surface (˜1.2). Dissociated species are found to have same average number of hydrogen bonds on both surfaces. As a consequence, the rutile surface has higher density of h-bonds at the surface than cassiterite, however, their strength is lower [N. Kumar et al., J. Chem. Phys. 134, 044706 (2011)]. This delicate balance is responsible for the different dynamical properties of both surfaces.

  8. Analysis and design of an ultrahigh temperature hydrogen-fueled MHD generator

    Science.gov (United States)

    Moder, Jeffrey P.; Myrabo, Leik N.; Kaminski, Deborah A.

    1993-01-01

    A coupled gas dynamics/radiative heat transfer analysis of partially ionized hydrogen, in local thermodynamic equilibrium, flowing through an ultrahigh temperature (10,000-20,000 K) magnetohydrodynamic (MHD) generator is performed. Gas dynamics are modeled by a set of quasi-one-dimensional, nonlinear differential equations which account for friction, convective and radiative heat transfer, and the interaction between the ionized gas and applied magnetic field. Radiative heat transfer is modeled using nongray, absorbing-emitting 2D and 3D P-1 approximations which permit an arbitrary variation of the spectral absorption coefficient with frequency. Gas dynamics and radiative heat transfer are coupled through the energy equation and through the temperature- and density-dependent absorption coefficient. The resulting nonlinear elliptic problem is solved by iterative methods. Design of such MHD generators as onboard, open-cycle, electric power supplies for a particular advanced airbreathing propulsion concept produced an efficient and compact 128-MWe generator characterized by an extraction ratio of 35.5 percent, a power density of 10,500 MWe/cu m, and a specific (extracted) energy of 324 MJe/kg of hydrogen. The maximum wall heat flux and total wall heat load were 453 MW/sq m and 62 MW, respectively.

  9. Risk-Based Explosive Safety Analysis

    Science.gov (United States)

    2016-11-30

    REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1...currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 30 November 2016 2. REPORT TYPE...Technical Paper 3. DATES COVERED (From - To) 01 November 2016 – 30 November 2016 4. TITLE AND SUBTITLE Risk-Based Explosive Safety Analysis 5a

  10. Risk and value analysis of SETI

    Science.gov (United States)

    Billingham, J.

    1990-01-01

    This paper attempts to apply a traditional risk and value analysis to the Search for Extraterrestrial Intelligence--SETI. In view of the difficulties of assessing the probability of success, a comparison is made between SETI and a previous search for extraterrestrial life, the biological component of Project Viking. Our application of simple Utility Theory, given some reasonable assumptions, suggests that SETI is at least as worthwhile as the biological experiment on Viking.

  11. Selected Tools for Risk Analysis in Logistics Processes

    Science.gov (United States)

    Kulińska, Ewa

    2012-03-01

    As each organization aims at managing effective logistics processes, risk factors can and should be controlled through proper system of risk management. Implementation of complex approach to risk management allows for the following: - evaluation of significant risk groups associated with logistics processes implementation, - composition of integrated strategies of risk management, - composition of tools for risk analysis in logistics processes.

  12. Community Energy: Analysis of Hydrogen Distributed Energy Systems with Photovoltaics for Load Leveling and Vehicle Refueling

    Energy Technology Data Exchange (ETDEWEB)

    Steward, D.; Zuboy, J.

    2014-10-01

    Energy storage could complement PV electricity generation at the community level. Because PV generation is intermittent, strategies must be implemented to integrate it into the electricity system. Hydrogen and fuel cell technologies offer possible PV integration strategies, including the community-level approaches analyzed in this report: (1) using hydrogen production, storage, and reconversion to electricity to level PV generation and grid loads (reconversion scenario); (2) using hydrogen production and storage to capture peak PV generation and refuel hydrogen fuel cell electric vehicles (FCEVs) (hydrogen fueling scenario); and (3) a comparison scenario using a battery system to store electricity for EV nighttime charging (electric charging scenario).

  13. Measurement and Analysis of the Diffusible Hydrogen in Underwater Wet Welding Joint

    Directory of Open Access Journals (Sweden)

    Kong Xiangfeng

    2016-01-01

    Full Text Available The diffusible hydrogen in steel weldments is one of the main reasons that led to hydrogen assisted cracking. In this paper, the results of literatures survey and preliminary tests of the diffusible hydrogen in underwater wet welding joint were presented. A fluid-discharge method of for measuring the diffusible hydrogen in weldment was introduced in detail. Two kinds of underwater welding electrode diffusible hydrogen are 26.5 mL/100g and 35.5 mL/100g by fluid-discharge method, which are high levels. The diffusible hydrogen of underwater welding is higher than atmospheric welding, and the result is closely related to welding material. The best way to control the diffusible hydrogen is adjusting welding material and improving fluidity of slag.

  14. Techno-economical Analysis of Hybrid PV-WT-Hydrogen FC System for a Residential Building with Low Power Consumption

    Directory of Open Access Journals (Sweden)

    Badea G.

    2016-12-01

    Full Text Available This paper shows a techno-economical analysis on performance indicators of hybrid solar-wind-hydrogen power generation system which supply with electricity a low - energy building, located in Cluj-Napoca. The case study had the main objectives, as follows: cost estimation, evaluation of energy and environmental performance for a fuel cell integrated into a small-scale hybrid system power generation and estimation of electrolytic hydrogen production based on renewable energy resources available on the proposed site. The results presented in this paper illustrate a case study for location Cluj-Napoca. The wind and solar resource can play an important role in energy needs for periods with "peak load" or intermittent energy supply. However, hydrogen production is dependent directly proportional to the availability of renewable energy resources, but the hydrogen can be considered as a storage medium for these renewable resources. It can be said that this study is a small-scale model analysis, a starting point for a detailed analysis of Romania's potential electrolytic production of hydrogen from renewable resources and supply electricity using fuel cells integrated into hybrid energy systems.

  15. The relationship between hydrogen and sulphate ions in precipitation-A numerical analysis of rain and snowfall chemistry.

    Science.gov (United States)

    Lefohn, A S; Krupa, S V

    1988-01-01

    Acidic rain has been identified as potentially harmful to the aquatic and terrestrial components of the ecosystem. Sulphate measured in rain and snow has been used as a surrogate indicator of acidic deposition. If sulphur dioxide controls are the means to limit acidic deposition, then the association between sulphate and hydrogen ion concentrations in precipitation is an important factor in establishing such limits. Selected data on rain and snowfall chemistry from the National Atmospheric Deposition Program (NADP), the Electric Power Research Institute's SURE, the utility industries' UAPSP, and the Department of Energy's MAP3S were reviewed. Numerical analyses were performed to assess the relationship between hydrogen and sulphate ion concentrations. The strength of the association between hydrogen and sulphate ions varied from site to site. In the Midwestern and Eastern regions, the Pearson correlation coefficient was over 0.50 while in the Central and Upper Midwestern parts of the United States, the correlation coefficients were less than 0.25. Regardless of the strength of the association between hydrogen and sulphate ions, all but one of the NADP/NTN sites used in our analysis exhibited at least 30% of the anions (sulphate, nitrate, and chloride) associated with cations other than hydrogen. For sites where the strength of the association was weak, between 65% and 98% of the anions appeared to be associated with cations other than hydrogen. Because a large percentage of the anions (i.e. sulphate, nitrate, and chloride) appear to be associated with cations other than hydrogen even at those sites where the association between hydrogen and sulphate ions was strong, the complex chemistry controlling the acidity in precipitation may make it difficult to predict the impact of a reduction in sulphate concentration.

  16. Investigating the role of atomic hydrogen on chloroethene reactions with iron using tafel analysis and electrochemical impedance spectroscopy.

    Science.gov (United States)

    Wang, Jiankang; Farrell, James

    2003-09-01

    Metallic iron filings are commonly employed as reducing agents in permeable barriers used for remediating groundwater contaminated by chlorinated solvents. Reactions of trichloroethylene (TCE) and tetrachloroethylene (PCE) with zerovalent iron were investigated to determine the role of atomic hydrogen in their reductive dechlorination. Experiments simultaneously measuring dechlorination and iron corrosion rates were performed to determine the fractions of the total current going toward dechlorination and hydrogen evolution. Corrosion rates were determined using Tafel analysis, and dechlorination rates were determined from rates of byproduct generation. Electrochemical impedance spectroscopy (EIS) was used to determine the number of reactions that controlled the observed rates of chlorocarbon disappearance, as well as the role of atomic hydrogen in TCE and PCE reduction. Comparison of iron corrosion rates with those for TCE reaction showed that TCE reduction occurred almost exclusively via atomic hydrogen at low pH values and via atomic hydrogen and direct electron transfer at neutral pH values. In contrast, reduction of PCE occurred primarily via direct electron transfer at both low and neutral pH values. At low pH values and micromolar concentrations, TCE reaction rates were faster than those for PCE due to more rapid reduction of TCE by atomic hydrogen. At neutral pH values and millimolar concentrations, PCE reaction rates were faster than those for TCE. This shift in relative reaction rates was attributed to a decreasing contribution of the atomic hydrogen reaction mechanism with increasing halocarbon concentrations and pH values. The EIS data showed that all the rate limitations for TCE and PCE dechlorination occurred during the transfer of the first two electrons. Results from this study show that differences in relative reaction rates of TCE and PCE with iron are dependent on the significance of the reduction pathway involving atomic hydrogen.

  17. An in vitro thermal analysis during different light-activated hydrogen peroxide bleaching

    Science.gov (United States)

    Kabbach, W.; Zezell, D. M.; Bandéca, M. C.; Pereira, T. M.; Andrade, M. F.

    2010-09-01

    This study measured the critical temperature reaching time and also the variation of temperature in the surface of the cervical region and within the pulp chamber of human teeth submitted to dental bleaching using 35% hydrogen peroxide gel activated by three different light sources. The samples were randomly divided into 3 groups ( n = 15), according to the catalyst light source: Halogen Light (HL), High Intensity Diode Laser (DL), and Light Emmited Diode (LED). The results of temperature variation were submitted to the analysis of variance and Tukey test with p bleaching for a short period of time. The LED source did not heat the target tissues significantly within the parameters used in this study.

  18. Multiple response optimization analysis for pretreatments of Tequila's stillages for VFAs and hydrogen production.

    Science.gov (United States)

    Espinoza-Escalante, Froylán M; Pelayo-Ortiz, Carlos; Gutiérrez-Pulido, Humberto; González-Alvarez, Víctor; Alcaraz-González, Víctor; Bories, André

    2008-09-01

    The objective of this work was study the effect of three pretreatments (alkalinization, thermical treatment, and sonication) on Tequila's stillages hydrolysis process in acidogenesis stage, through the following response variables: soluble chemical oxygen demand (CODs), total sugar and volatile fatty acids profile and the hydrogen production at the time. The stillages were subject to these pretreatments (according to a 2(3) factorial design); afterward they were transferred to a batch reactor at 35 degrees C and inoculated with an anaerobic digestor sludge. Multiple response optimization (MRO) analysis was done to find the global optimum for the response variables described above. This optimum is able to maximize simultaneously all these variables. It was found adequate to be useful hydrolyzing the organic matter present in Tequila's stillages. Mathematical models were fitted to observe the estimated effects of pretreatments on each response variable, then the MRO was applied.

  19. 14 CFR 417.225 - Debris risk analysis.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Debris risk analysis. 417.225 Section 417... OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.225 Debris risk analysis. A flight safety analysis must demonstrate that the risk to the public potentially exposed to inert and...

  20. Conceptual issues with risk analysis in Switzerland

    Science.gov (United States)

    Nicolet, Pierrick; Jaboyedoff, Michel; Lévy, Sébastien

    2015-04-01

    Risk analysis is a tricky procedure, where one can easily make mistakes. Indeed, although risk equations are rather general, transferring a methodology to another context or hazard type can often lead to inaccuracies or even significant errors. To illustrate this, common mistakes made with the Swiss methodology are presented, together with possible solutions. This includes the following: Risk analysis for moving objects only takes the process dimension into account (e.g. the length of a road section potentially affected by a landslide), but not the object dimension (e.g. the cars length). This is a fair simplification as long as the object dimension is considerably smaller than the process dimension. However, when the object is large compared to the process (e.g. rockfalls on a train), the results will be wrong. This problem can be illustrated by considering two blocs. According to this methodology a 1 m diameter bloc will be twice more susceptible to reach a train than a 50 cm bloc. This is obviously not correct. When it comes to rockfalls risk analysis on roads or railway found in the literature, the bloc dimension is usually neglected, in favour of the object dimension, which is a fair assumption in this context. However, it is possible to include both dimensions by using the sum of the lengths instead of one of them. Risk analysis is usually performed using 3 different scenarios, for 3 different ranges of return periods, namely 1-30, 30-100 and 100-300 years. In order to be conservative, the operator commonly considers the magnitude of the worst event that happens with a return period included between the class bounds, which means that the operator evaluates the magnitude reached or overpassed with a return period of 30, 100 and 300 years respectively. Then, since the magnitude corresponds to the upper bounds of the classes, risk is calculated using the frequency corresponding to these return periods and not to the middle of the class (and also subtracting the

  1. AGROFOREST SYSTEM INVESTMENT ANALYSIS UNDER RISK

    Directory of Open Access Journals (Sweden)

    Luiz Moreira Coelho Junior

    2008-12-01

    Full Text Available Agroforestry System is the ecological and economical interaction of the use of the land, with the combination ofagriculture, livestock and forest production, in temporary sequence and in a simultaneous way. The studies of investments in projectsassume the existence of risks and uncertainties. An alternative to reduce the risk in the forest investment is the association with theagricultural. This work analyzed the situations of risk of a system agroflorestal. Monte Carlo s method comes from the theory ofsimulations and stands out as a powerful and useful tool to provide a distribution of probabilities for the analysis of decision. A totalof 10,000 interactions of the Net Present Value (VPL, of Internal Rate of Return (TIR and of the Equivalent Periodic Benefit (BPEwere made in order to establish the probability distribution. The results presented 78.65% of chance of VPL being US$ 1,410.00;77.56% of chance of TIR being 36.36%, and; 75.39% of chance of BPE being US$ 309.70; the agroforestry system presented lowinvestment risk; and the livestock is the main product of the agrossilvopastoril system, followed by charcoal.

  2. Radiation risks: critical analysis and commentary.

    Science.gov (United States)

    Barrett, Bruce; Stiles, Melissa; Patterson, Jeff

    2012-01-01

    1) To review and summarize what is known about the health risks of radiation. 2) To compare risks from medical imaging to background radiation and to exposure from nuclear accidents. Literature review and summative critical analysis. Over the past several years, physicians and patients have become increasingly aware of the potential risks of radiation exposure from medical imaging. The Fukushima disaster further heightened public awareness of hazards associated with radiation and radioactivity. In the case of medical imaging, small but real risks of cancer and other radiation-induced disease must be balanced against potential benefits of improved diagnostic accuracy. The ethical principle of autonomy tells us that patients should be informed of potential benefits and harms of radiation imaging, and should participate in shared decision making. In the case of nuclear power, benefits and especially harms are exceptionally difficult to estimate accurately. Nevertheless, we know that hazards from today's nuclear power plants will persist for many years, affecting future generations not benefiting from electrical power generated today. A deeper and more widespread understanding of potential benefits and harms of personal and societal choices relating to radiation exposure may lead to improved medical and societal decision-making. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Approach to uncertainty in risk analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rish, W.R.

    1988-08-01

    In the Fall of 1985 EPA's Office of Radiation Programs (ORP) initiated a project to develop a formal approach to dealing with uncertainties encountered when estimating and evaluating risks to human health and the environment. Based on a literature review of modeling uncertainty, interviews with ORP technical and management staff, and input from experts on uncertainty analysis, a comprehensive approach was developed. This approach recognizes by design the constraints on budget, time, manpower, expertise, and availability of information often encountered in ''real world'' modeling. It is based on the observation that in practice risk modeling is usually done to support a decision process. As such, the approach focuses on how to frame a given risk modeling problem, how to use that framing to select an appropriate mixture of uncertainty analyses techniques, and how to integrate the techniques into an uncertainty assessment that effectively communicates important information and insight to decision-makers. The approach is presented in this report. Practical guidance on characterizing and analyzing uncertainties about model form and quantities and on effectively communicating uncertainty analysis results is included. Examples from actual applications are presented.

  4. Analysis of the composition of incident hydrogen ion beams accelerated by a Van de Graaff electrostatic accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Bazhukov, S.I.; Kibardin, A.V.; Pyatkova, T.M. (Urals Polytechnical Inst., Sverdlovsk (USSR))

    1991-06-01

    A new technique is proposed for analysis of the composition of incident hydrogen ion beams accelerated by Van de Graaff electrostatic accelerators. The procedure is based on the analysis of the energy distribution of the neutral fraction of the hydrogen ion beam by a silicon surface barrier detector. It is shown that along with the main beam components (H{sup +}, H{sup 0}) at the energy E{sub 0}, another component exists at the energy 0.25E{sub 0}. This component is brought about through acceleration and breakup of molecular H{sub 2}{sup +} ions. However such inhomogeneities do not play a noticeable role in formation of the low energy tail of hydrogen ions backscattered from thin self-supporting films. (orig.).

  5. Integrated analysis of transportation demand pathway options for hydrogen production, storage, and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, C.E.S. [Directed Technologies Inc., Arlington, VA (United States)

    1996-10-01

    Directed Technologies, Inc. has begun the development of a computer model with the goal of providing guidance to the Hydrogen Program Office regarding the most cost effective use of limited resources to meet national energy security and environmental goals through the use of hydrogen as a major energy carrier. The underlying assumption of this programmatic pathway model is that government and industry must work together to bring clean hydrogen energy devices into the marketplace. Industry cannot provide the long term resources necessary to overcome technological, regulatory, institutional, and perceptual barriers to the use of hydrogen as an energy carrier, and government cannot provide the substantial investments required to develop hydrogen energy products and increased hydrogen production capacity. The computer model recognizes this necessary government/industry partnership by determining the early investments required by government to bring hydrogen energy end uses within the time horizon and profitability criteria of industry, and by estimating the subsequent investments required by industry. The model then predicts the cost/benefit ratio for government, based on contributions of each hydrogen project to meeting societal goals, and it predicts the return on investment for industry. Sensitivity analyses with respect to various government investments such as hydrogen research and development and demonstration projects will then provide guidance as to the most cost effective mix of government actions. The initial model considers the hydrogen transportation market, but this programmatic pathway methodology will be extended to other market segments in the future.

  6. The Assessment of Hydrogen Energy Systems for Fuel Cell Vehicles Using Principal Componenet Analysis and Cluster Analysis

    DEFF Research Database (Denmark)

    Ren, Jingzheng; Tan, Shiyu; Dong, Lichun

    2012-01-01

    Hydrogen energy which has been recognized as an alternative instead of fossil fuel has been developed rapidly in fuel cell vehicles. Different hydrogen energy systems have different performances on environmental, economic, and energy aspects. A methodology for the quantitative evaluation...... to verify the correctness and accuracy of the principal components (PCs) determined by PCA in this paper. A case including 11 different hydrogen energy systems for fuel cell vehicles has been studied in this paper, and the system using steam reforming of natural gas for hydrogen production, pipeline...... for transportation of hydrogen, hydrogen gas tank for the storage of hydrogen at refueling stations, and gaseous hydrogen as power energy for fuel cell vehicles has been recognized as the best scenario. Also, the clustering results calculated by CA are consistent with those determined by PCA, denoting...

  7. Comparative analysis of seismic risk assessment methodology

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Kyoo; Kim, Tae Woon; Hwang, Mi Jung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-07-01

    SRA methodologies are separated into SPSA and SMM. SPSA methodology that has been widely used for seismic risk analysis has two kinds of methodologies such as Zion method and SSMRP method. SPSA methodology is suitable to interfacing with the analysis of internal event. However, the results of SPSA have uncertainties because of uncertainties in seismic hazard analysis and subjective judgement. Zion method specially developed for commercial use is less expensive and less time consuming but more uncertain than SSMRP method, since the former performs the fragility analysis less in detail than the latter. SMM is impossible to interface with the analysis of internal event but the uncertainties that are occurred during seismic hazard analysis is reduced because of the screening using RLE (review level earthquake). Therefore, if SPSA-based SMM methodology is chosen to be developed, the results of SRA will be more reliable and it requires low costs and time. In addition, the new methodology will require the development of a new evaluating code for SRA. (Author) 26 refs., 25 figs., 16 tabs.

  8. Risk-driven security testing using risk analysis with threat modeling approach.

    Science.gov (United States)

    Palanivel, Maragathavalli; Selvadurai, Kanmani

    2014-01-01

    Security testing is a process of determining risks present in the system states and protects them from vulnerabilities. But security testing does not provide due importance to threat modeling and risk analysis simultaneously that affects confidentiality and integrity of the system. Risk analysis includes identification, evaluation and assessment of risks. Threat modeling approach is identifying threats associated with the system. Risk-driven security testing uses risk analysis results in test case identification, selection and assessment to prioritize and optimize the testing process. Threat modeling approach, STRIDE is generally used to identify both technical and non-technical threats present in the system. Thus, a security testing mechanism based on risk analysis results using STRIDE approach has been proposed for identifying highly risk states. Risk metrics considered for testing includes risk impact, risk possibility and risk threshold. Risk threshold value is directly proportional to risk impact and risk possibility. Risk-driven security testing results in reduced test suite which in turn reduces test case selection time. Risk analysis optimizes the test case selection and execution process. For experimentation, the system models namely LMS, ATM, OBS, OSS and MTRS are considered. The performance of proposed system is analyzed using Test Suite Reduction Rate (TSRR) and FSM coverage. TSRR varies from 13.16 to 21.43% whereas FSM coverage is achieved up to 91.49%. The results show that the proposed method combining risk analysis with threat modeling identifies states with high risks to improve the testing efficiency.

  9. High-temperature nuclear reactor power plant cycle for hydrogen and electricity production – numerical analysis

    Directory of Open Access Journals (Sweden)

    Dudek Michał

    2016-01-01

    Full Text Available High temperature gas-cooled nuclear reactor (called HTR or HTGR for both electricity generation and hydrogen production is analysed. The HTR reactor because of the relatively high temperature of coolant could be combined with a steam or gas turbine, as well as with the system for heat delivery for high-temperature hydrogen production. However, the current development of HTR’s allows us to consider achievable working temperature up to 750°C. Due to this fact, industrial-scale hydrogen production using copper-chlorine (Cu-Cl thermochemical cycle is considered and compared with high-temperature electrolysis. Presented calculations show and confirm the potential of HTR’s as a future solution for hydrogen production without CO2 emission. Furthermore, integration of a hightemperature nuclear reactor with a combined cycle for electricity and hydrogen production may reach very high efficiency and could possibly lead to a significant decrease of hydrogen production costs.

  10. Analysis of Production and Delivery Center Hydrogen Applied to the Southern Patagonian Circuit

    Directory of Open Access Journals (Sweden)

    Maximiliano Fernando Medina

    2016-08-01

    Full Text Available The Desire department of the province of Santa Cruz, Argentina, presents the greatest potential electrolytic Hydrogen Production Country, From Three primary sources of sustainable energy: wind, solar, biomass. There, the Hydrogen Plant of Pico Truncado has capacity central production of hydrogen 100m3 of H2 / day, enough to supply 353 vehicles with hybrid fuel called HGNC, made by cutting 12% V / V of hydrogen in CNG (in situ at each station. Puerto Deseado, Fitz Roy, Caleta Olivia, Las Heras, Comodoro Rivadavia, Sarmiento and the Ancients: From the production cost, the cost of delivering hydrogen to the Southern Patagonian circuit comprised analyzed. Considering various local parameters are determined as a way of delivering more profitable virtual pipeline, with total cost of hydrogen estimated 6.5 USD / kg H2 and HGNC shipped in the station at 0.50 USD / Nm3.

  11. Model risk analysis for risk management and option pricing

    NARCIS (Netherlands)

    Kerkhof, F.L.J.

    2003-01-01

    Due to the growing complexity of products in financial markets, market participants rely more and more on quantitative models for trading and risk management decisions. This introduces a fairly new type of risk, namely, model risk. In the first part of this thesis we investigate the quantitative

  12. FORTRAN computer program for seismic risk analysis

    Science.gov (United States)

    McGuire, Robin K.

    1976-01-01

    A program for seismic risk analysis is described which combines generality of application, efficiency and accuracy of operation, and the advantage of small storage requirements. The theoretical basis for the program is first reviewed, and the computational algorithms used to apply this theory are described. The information required for running the program is listed. Published attenuation functions describing the variation with earthquake magnitude and distance of expected values for various ground motion parameters are summarized for reference by the program user. Finally, suggestions for use of the program are made, an example problem is described (along with example problem input and output) and the program is listed.

  13. Car-Parrinello Molecular Dynamics Simulations of Infrared Spectra of Crystalline Vitamin C with Analysis of Double Minimum Proton Potentials for Medium-Strong Hydrogen Bonds.

    Science.gov (United States)

    Brela, Mateusz Z; Wójcik, Marek J; Boczar, Marek; Witek, Łukasz; Yasuda, Mitsuru; Ozaki, Yukihiro

    2015-06-25

    We studied proton dynamics of a hydrogen bonds of the crystalline l-ascorbic acid. Our approach was based on the Car-Parrinello molecular dynamics. The focal point of our study was simulation of the infrared spectra of l-ascorbic acid associated with the O-H stretching modes that are very sensitive to the strength of hydrogen bonding. In the l-ascorbic acid there are four kinds of hydrogen bonds. We calculated their spectra by using anharmonic approximation and the time course of the dipole moment function as obtained from the Car-Parrinello simulation. The quantization of the nuclear motion of the protons was made to perform detailed analysis of strength and properties of hydrogen bonds. We presented double minimum proton potentials with small value of barriers for medium-strong hydrogen bonds. We have also shown the difference character of medium-strong hydrogen bonds compared to weaker hydrogen bonds in the l-ascorbic acid.

  14. Risk analysis methodology designed for small and medium enterprises

    OpenAIRE

    Ladislav Beránek; Radim Remeš

    2009-01-01

    The aim of this paper is to present risk analysis procedures successfully applied by several Czech small and medium enterprises. The paper presents in detail the individual steps we use in risk analysis of small and medium enterprises in the Czech Republic. Suggested method to risk analysis is based on the modification of the FRAP methodology and the BITS recommendation. Modifications of both methodologies are described in detail. We propose modified risk analysis methodology which is quick a...

  15. Risk Analysis Approach to Rainwater Harvesting Systems

    Directory of Open Access Journals (Sweden)

    Nadia Ursino

    2016-08-01

    Full Text Available Urban rainwater reuse preserves water resources and promotes sustainable development in rapidly growing urban areas. The efficiency of a large number of urban water reuse systems, operating under different climate and demand conditions, is evaluated here on the base of a new risk analysis approach. Results obtained by probability analysis (PA indicate that maximum efficiency in low demanding scenarios is above 0.5 and a threshold, distinguishing low from high demanding scenarios, indicates that in low demanding scenarios no significant improvement in performance may be attained by increasing the storage capacity of rainwater harvesting tanks. Threshold behaviour is displayed when tank storage capacity is designed to match both the average collected volume and the average reuse volume. The low demand limit cannot be achieved under climate and operating conditions characterized by a disproportion between harvesting and demand volume.

  16. Quantitative effects on cardiovascular risk factors and coronary heart disease risk of replacing partially hydrogenated vegetable oils with other fats and oils.

    Science.gov (United States)

    Mozaffarian, D; Clarke, R

    2009-05-01

    Reduced consumption of trans-fatty acids (TFA) is desirable to lower coronary heart disease (CHD) risk. In practice, partially hydrogenated vegetable oils (PHVO) that contain both TFAs and other fatty acids are the unit of replacement and could be replaced with diverse alternative fats and oils. We performed quantitative estimates of CHD effects if a person's PHVO consumption were to be replaced with alternative fats and oils based on (1) randomized dietary trials and (2) prospective observational studies. We performed meta-analyses of (1) the effects of TFAs on blood lipids and lipoproteins in controlled dietary trials and (2) associations of habitual TFA consumption with CHD outcomes in prospective cohort studies. On the basis of these results and corresponding findings for saturated fatty acids (SFA), cis-monounsaturated fatty acids (MUFA) and cis-polyunsaturated fatty acids (PUFA), we calculated the effects on CHD risk for replacing 7.5% of energy from three different PHVO formulations (containing 20, 35 or 45% TFAs) with butter, lard, palm or vegetable oils. In controlled trials, each 1% energy replacement of TFAs with SFAs, MUFAs or PUFAs, respectively, decreased the total cholesterol (TC)/high-density lipoprotein cholesterol (HDL-C) ratio by 0.31, 0.54 and 0.67; the apolipoprotein (Apo)-B/ApoAI ratio by 0.007, 0.010 and 0.011; and lipoprotein (Lp)(a) by 3.76, 1.39 and 1.11 mg/l (Pfats from one trial. On the basis of these risk factor changes in controlled trials, CHD risk would be variably decreased by different fats and oils replacing 7.5% of energy from 20% TFA PHVO (CHD risk reduction: -2.7% (butter) to -9.9% (canola)); 35% TFA PHVO (-11.9% (butter) to -16.0% (canola)); or 45% TFA PHVO (-17.6% (butter) to -19.8% (canola)). In prospective cohort studies, each 2% energy replacement of TFAs with SFAs, MUFAs or PUFAs would lower CHD risk by 17% (95% confidence interval (CI)=7-25%), 21% (95% CI=12-30%) or 24% (95% CI=15-33%), respectively. On the basis of

  17. An analysis of quantum effects on the thermodynamic properties of cryogenic hydrogen using the path integral method.

    Science.gov (United States)

    Nagashima, H; Tsuda, S; Tsuboi, N; Koshi, M; Hayashi, K A; Tokumasu, T

    2014-04-07

    In this paper, we describe the analysis of the thermodynamic properties of cryogenic hydrogen using classical molecular dynamics (MD) and path integral MD (PIMD) method to understand the effects of the quantum nature of hydrogen molecules. We performed constant NVE MD simulations across a wide density-temperature region to establish an equation of state (EOS). Moreover, the quantum effect on the difference of molecular mechanism of pressure-volume-temperature relationship was addressed. The EOS was derived based on the classical mechanism idea only using the MD simulation results. Simulation results were compared with each MD method and experimental data. As a result, it was confirmed that although the EOS on the basis of classical MD cannot reproduce the experimental data of saturation property of hydrogen in the high-density region, the EOS on the basis of PIMD well reproduces those thermodynamic properties of hydrogen. Moreover, it was clarified that taking quantum effects into account makes the repulsion force larger and the potential well shallower. Because of this mechanism, the intermolecular interaction of hydrogen molecules diminishes and the virial pressure increases.

  18. Pleiotropic analysis of cancer risk loci on esophageal adenocarcinoma risk

    Science.gov (United States)

    Lee, Eunjung; Stram, Daniel O.; Ek, Weronica E.; Onstad, Lynn E; MacGregor, Stuart; Gharahkhani, Puya; Ye, Weimin; Lagergren, Jesper; Shaheen, Nicholas J.; Murray, Liam J.; Hardie, Laura J; Gammon, Marilie D.; Chow, Wong-Ho; Risch, Harvey A.; Corley, Douglas A.; Levine, David M; Whiteman, David C.; Bernstein, Leslie; Bird, Nigel C.; Vaughan, Thomas L.; Wu, Anna H.

    2015-01-01

    Background Several cancer-associated loci identified from genome-wide association studies (GWAS) have been associated with risks of multiple cancer sites, suggesting pleiotropic effects. We investigated whether GWAS-identified risk variants for other common cancers are associated with risk of esophageal adenocarcinoma (EA) or its precursor, Barrett's esophagus (BE). Methods We examined the associations between risks of EA and BE and 387 single nucleotide polymorphisms (SNPs) that have been associated with risks of other cancers, by using genotype imputation data on 2,163 control participants and 3,885 (1,501 EA and 2,384 BE) case patients from the Barrett's and Esophageal Adenocarcinoma Genetic Susceptibility Study, and investigated effect modification by smoking history, body mass index (BMI), and reflux/heartburn. Results After correcting for multiple testing, none of the tested 387 SNPs were statistically significantly associated with risk of EA or BE. No evidence of effect modification by smoking, BMI, or reflux/heartburn was observed. Conclusions Genetic risk variants for common cancers identified from GWAS appear not to be associated with risks of EA or BE. Impact To our knowledge, this is the first investigation of pleiotropic genetic associations with risks of EA and BE. PMID:26364162

  19. First principles analysis of hydrogen chemisorption on Pd-Re alloyed overlayers and alloyed surfaces

    DEFF Research Database (Denmark)

    Pallassana, Venkataraman; Neurock, Matthew; Hansen, Lars Bruno

    2000-01-01

    Gradient corrected periodic density functional theory (DFT-GGA) slab calculations were used to examine the chemisorption of atomic hydrogen on various Pd-Re alloyed overlayers and uniformly alloyed surfaces. Adsorption was examined at 33% surface coverage, where atomic hydrogen preferred the thre...

  20. Analysis of the holistic impact of the Hydrogen Economy on the coal industry

    Science.gov (United States)

    Lusk, Shannon Perry

    As gas prices soar and energy demand continues to grow amidst increasingly stringent environmental regulations and an assortment of global pressures, implementing alternative energy sources while considering their linked economic, environmental and societal impacts becomes a more pressing matter. The Hydrogen Economy has been proposed as an answer to meeting the increasing energy demand for electric power generation and transportation in an environmentally benign way. Based on current hydrogen technology development, the most practical feedstock to fuel the Hydrogen Economy may prove to be coal via hydrogen production at FutureGen plants. The planned growth of the currently conceived Hydrogen Economy will cause dramatic impacts, some good and some bad, on the economy, the environment, and society, which are interlinked. The goal of this research is to provide tools to inform public policy makers in sorting out policy options related to coal and the Hydrogen Economy. This study examines the impact of a transition to a Hydrogen Economy on the coal industry by creating FutureGen penetration models, forecasting coal MFA's which clearly provide the impact on coal production and associated environmental impacts, and finally formulating a goal programming model that seeks the maximum benefit to society while analyzing the trade-offs between environmental, social, and economical concerns related to coal and the Hydrogen Economy.

  1. Molecular-dynamics analysis of the diffusion of molecular hydrogen in all-silica sodalite

    NARCIS (Netherlands)

    Van den Berg, A.W.C.; Bromley, S.T.; Flikkema, E.; Wojdel, J.; Maschmeyer, T.; Jansen, J.C.

    2004-01-01

    In order to investigate the technical feasibility of crystalline porous silicates as hydrogen storage materials, the self-diffusion of molecular hydrogen in all-silica sodalite is modeled using large-scale classical molecular-dynamics simulations employing full lattice flexibility. In the

  2. Final technical report [Molecular genetic analysis of biophotolytic hydrogen production in green algae

    Energy Technology Data Exchange (ETDEWEB)

    Mets, Laurens

    2000-12-31

    The principal objective of this project was to identify genes necessary for biophotolytic hydrogen production in green algae, using Chlamydomonas reinhardtii as an experimental organism. The main strategy was to isolate mutants that are selectively deficient in hydrogen production and to genetically map, physically isolate, and ultimately sequence the affected genes.

  3. Analysis of the microbial community of the biocathode of a hydrogen-producing microbial electrolysis cell

    NARCIS (Netherlands)

    Croese, E.; Pereira, M.A.; Euverink, G.J.W.; Stams, A.J.M.; Geelhoed, J.S.

    2011-01-01

    The microbial electrolysis cell (MEC) is a promising system for hydrogen production. Still, expensive catalysts such as platinum are needed for efficient hydrogen evolution at the cathode. Recently, the possibility to use a biocathode as an alternative for platinum was shown. The microorganisms

  4. Fire Protection Engineering Design Brief Template. Hydrogen Refueling Station.

    Energy Technology Data Exchange (ETDEWEB)

    LaFleur, Angela Christine [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Muna, Alice Baca [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Groth, Katrina M. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    Building a hydrogen infrastructure system is critical to supporting the development of alternate- fuel vehicles. This report provides a methodology for implementing a performance-based design of an outdoor hydrogen refueling station that does not meet specific prescriptive requirements in NFPA 2, The Hydrogen Technologies Code . Performance-based designs are a code-compliant alternative to meeting prescriptive requirements. Compliance is demonstrated by comparing a prescriptive-based fueling station design with a performance-based design approach using Quantitative Risk Assessment (QRA) methods and hydrogen risk assessment tools. This template utilizes the Sandia-developed QRA tool, Hydrogen Risk Analysis Models (HyRAM), which combines reduced-order deterministic models that characterize hydrogen release and flame behavior with probabilistic risk models to quantify risk values. Each project is unique and this template is not intended to account for site-specific characteristics. Instead, example content and a methodology are provided for a representative hydrogen refueling site which can be built upon for new hydrogen applications.

  5. Melanin Bleaching With Warm Hydrogen Peroxide and Integrated Immunohistochemical Analysis: An Automated Platform.

    Science.gov (United States)

    Liu, Chia-Hsing; Lin, Chih-Hung; Tsai, Min-Jan; Chen, Yu-Hsuan; Yang, Sheau-Fang; Tsai, Kun-Bow

    2018-02-01

    Diagnosing melanocytic lesions is among the most challenging problems in the practice of pathology. The difficulty of physically masking melanin pigment and the similarity of its color to commonly used chromogens often complicate examination of the cytomorphology and immunohistochemical staining results for tumor cells. Melanin bleach can be very helpful for histopathological diagnosis of heavily pigmented melanocytic lesions. Although various depigmentation methods have been reported, no standardized methods have been developed. This study developed a fully automated platform that incorporates hydrogen peroxide-based melanin depigmentation in an automated immunohistochemical analysis. The utility of the method was tested in 1 cell block of malignant melanoma cells in pleural effusion, 10 ocular melanoma tissue samples, and 10 cutaneous melanoma tissue samples. Our results demonstrated that the proposed method, which can be performed in only 3 hours, effectively preserves cell cytomorphology and immunoreactivity. The method is particularly effective for removing melanin pigment to facilitate histopathological examination of cytomorphology and for obtaining an unmasked tissue section for immunohistochemical analysis.

  6. Thermal Analysis on Cryogenic Liquid Hydrogen Tank on an Unmanned Aerial Vehicle System

    Science.gov (United States)

    Wang, Xiao-Yen; Harpster, George; Hunter, James

    2007-01-01

    Thermal analyses are performed on the liquid hydrogen (LH2) tank designed for an unmanned aerial vehicle (UAV) powered by solar arrays and a regenerative proton-exchange membrane (PEM) fuel cell. A 14-day cruise mission at a 65,000 ft altitude is considered. Thermal analysis provides the thermal loads on the tank system and the boiling-off rates of LH2. Different approaches are being considered to minimize the boiling-off rates of the LH2. It includes an evacuated multilayer insulation (MLI) versus aerogel insulation on the LH2 tank and aluminum versus stainless steel spacer rings between the inner and outer tank. The resulting boil-off rates of LH2 provided by the one-dimensional model and three-dimensional finite element analysis (FEA) on the tank system are presented and compared to validate the results of the three-dimensional FEA. It concludes that heat flux through penetrations by conduction is as significant as that through insulation around the tank. The tank system with MLI insulation and stainless steel spacer rings result in the lowest boiling-off rate of LH2.

  7. Analysis of overlapped and noisy hydrogen/deuterium exchange mass spectra.

    Science.gov (United States)

    Guttman, Miklos; Weis, David D; Engen, John R; Lee, Kelly K

    2013-12-01

    Noisy and overlapped mass spectrometry data hinder the sequence coverage that can be obtained from hydrogen deuterium exchange analysis, and places a limit on the complexity of the samples that can be studied by this technique. Advances in instrumentation have addressed these limits, but as the complexity of the biological samples under investigation increases, these problems are re-encountered. Here we describe the use of binomial distribution fitting with asymmetric linear squares regression for calculating the accurate deuterium content for mass envelopes of low signal or that contain significant overlap. The approach is demonstrated with a test data set of HIV Env gp140 wherein inclusion of the new analysis regime resulted in obtaining exchange data for 42 additional peptides, improving the sequence coverage by 11%. At the same time, the precision of deuterium uptake measurements was improved for nearly every peptide examined. The improved processing algorithms also provide an efficient method for deconvolution of bimodal mass envelopes and EX1 kinetic signatures. All these functions and visualization tools have been implemented in the new version of the freely available software, HX-Express v2.

  8. Analysis of near-term production and market opportunities for hydrogen and related activities

    Energy Technology Data Exchange (ETDEWEB)

    Mauro, R.; Leach, S. [National Hydrogen Association, Washington, DC (United States)

    1995-09-01

    This paper summarizes current and planned activities in the areas of hydrogen production and use, near-term venture opportunities, and codes and standards. The rationale for these efforts is to assess industry interest and engage in activities that move hydrogen technologies down the path to commercialization. Some of the work presented in this document is a condensed, preliminary version of reports being prepared under the DOE/NREL contract. In addition, the NHA work funded by Westinghouse Savannah River Corporation (WSRC) to explore the opportunities and industry interest in a Hydrogen Research Center is briefly described. Finally, the planned support of and industry input to the Hydrogen Technical Advisory Panel (HTAP) on hydrogen demonstration projects is discussed.

  9. Analysis of Material Sample Heated by Impinging Hot Hydrogen Jet in a Non-Nuclear Tester

    Science.gov (United States)

    Wang, Ten-See; Foote, John; Litchford, Ron

    2006-01-01

    A computational conjugate heat transfer methodology was developed and anchored with data obtained from a hot-hydrogen jet heated, non-nuclear materials tester, as a first step towards developing an efficient and accurate multiphysics, thermo-fluid computational methodology to predict environments for hypothetical solid-core, nuclear thermal engine thrust chamber. The computational methodology is based on a multidimensional, finite-volume, turbulent, chemically reacting, thermally radiating, unstructured-grid, and pressure-based formulation. The multiphysics invoked in this study include hydrogen dissociation kinetics and thermodynamics, turbulent flow, convective and thermal radiative, and conjugate heat transfers. Predicted hot hydrogen jet and material surface temperatures were compared with those of measurement. Predicted solid temperatures were compared with those obtained with a standard heat transfer code. The interrogation of physics revealed that reactions of hydrogen dissociation and recombination are highly correlated with local temperature and are necessary for accurate prediction of the hot-hydrogen jet temperature.

  10. Hydrogen Fueling Station Using Thermal Compression: a techno-economic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kriha, Kenneth [Gas Technology Inst., Des Plaines, IL (United States); Petitpas, Guillaume [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Melchionda, Michael [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soto, Herie [Shell, Houston TX (United States); Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Yanli [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-11

    The goal of this project was to demonstrate the technical and economic feasibility of using thermal compression to create the hydrogen pressure necessary to operate vehicle hydrogen fueling stations. The concept of utilizing the exergy within liquid hydrogen to build pressure rather than mechanical components such as compressors or cryogenic liquid pumps has several advantages. In theory, the compressor-less hydrogen station will have lower operating and maintenance costs because the compressors found in conventional stations require large amounts of electricity to run and are prone to mechanical breakdowns. The thermal compression station also utilizes some of the energy used to liquefy the hydrogen as work to build pressure, this is energy that in conventional stations is lost as heat to the environment.

  11. Risk of Pore Water Hydrogen Sulfide Toxicity in Dredged Material Bioassays

    Science.gov (United States)

    1995-11-01

    concentrations must be diluted prior to analysis. Photometric determinations are made with a spec- trophotometer. The iodometric titration method is recommended...include a spectrophotometric procedure using methylene blue, iodometric titra- tion, and a potentiometric method. The methylene blue method (allows for

  12. NMR Analysis of Amide Hydrogen Exchange Rates in a Pentapeptide-Repeat Protein from A. thaliana.

    Science.gov (United States)

    Xu, Shenyuan; Ni, Shuisong; Kennedy, Michael A

    2017-05-23

    At2g44920 from Arabidopsis thaliana is a pentapeptide-repeat protein (PRP) composed of 25 repeats capped by N- and C-terminal α-helices. PRP structures are dominated by four-sided right-handed β-helices typically consisting of mixtures of type II and type IV β-turns. PRPs adopt repeated five-residue (Rfr) folds with an Rfr consensus sequence (STAV)(D/N)(L/F)(S/T/R)(X). Unlike other PRPs, At2g44920 consists exclusively of type II β-turns. At2g44920 is predicted to be located in the thylakoid lumen although its biochemical function remains unknown. Given its unusual structure, we investigated the biophysical properties of At2g44920 as a representative of the β-helix family to determine if it had exceptional global stability, backbone dynamics, or amide hydrogen exchange rates. Circular dichroism measurements yielded a melting point of 62.8°C, indicating unexceptional global thermal stability. Nuclear spin relaxation measurements indicated that the Rfr-fold core was rigid with order parameters ranging from 0.7 to 0.9. At2g44920 exhibited a striking range of amide hydrogen exchange rates spanning 10 orders of magnitude, with lifetimes ranging from minutes to several months. A weak correlation was found among hydrogen exchange rates, hydrogen bonding energies, and amino acid solvent-accessible areas. Analysis of contributions from fast (approximately picosecond to nanosecond) backbone dynamics to amide hydrogen exchange rates revealed that the average order parameter of amides undergoing fast exchange was significantly smaller compared to those undergoing slow exchange. Importantly, the activation energies for amide hydrogen exchange were found to be generally higher for the slowest exchanging amides in the central Rfr coil and decreased toward the terminal coils. This could be explained by assuming that the concerted motions of two preceding or following coils required for hydrogen bond disruption and amide hydrogen exchange have a higher activation energy

  13. Cost Benefit Analysis of Performing a Pilot Project for Hydrogen-Powered Ground Support Equipment at Lemoore Naval Air Station

    Science.gov (United States)

    2006-12-01

    Benefits of Fuel Cells." Bullnet eCommerce Solutions, Bull Group. http://www.bullnet.co.uk/ (accessed November 25, 2006). "Hydrogen Production and...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA MBA PROFESSIONAL REPORT Cost Benefit Analysis of Performing a Pilot Project for...blank) 2. REPORT DATE December 2006 3. REPORT TYPE AND DATES COVERED MBA Professional Report 4. TITLE AND SUBTITLE: Cost Benefit Analysis of

  14. Overcoming barriers to integrating economic analysis into risk assessment.

    Science.gov (United States)

    Hoffmann, Sandra

    2011-09-01

    Regulatory risk analysis is designed to provide decisionmakers with a clearer understanding of how policies are likely to affect risk. The systems that produce risk are biological, physical, and social and economic. As a result, risk analysis is an inherently interdisciplinary task. Yet in practice, risk analysis has been interdisciplinary in only limited ways. Risk analysis could provide more accurate assessments of risk if there were better integration of economics and other social sciences into risk assessment itself. This essay examines how discussions about risk analysis policy have influenced the roles of various disciplines in risk analysis. It explores ways in which integrated bio/physical-economic modeling could contribute to more accurate assessments of risk. It reviews examples of the kind of integrated economics-bio/physical modeling that could be used to enhance risk assessment. The essay ends with a discussion of institutional barriers to greater integration of economic modeling into risk assessment and provides suggestions on how these might be overcome. © 2011 Society for Risk Analysis.

  15. An Emerging New Risk Analysis Science: Foundations and Implications.

    Science.gov (United States)

    Aven, Terje

    2017-09-07

    To solve real-life problems-such as those related to technology, health, security, or climate change-and make suitable decisions, risk is nearly always a main issue. Different types of sciences are often supporting the work, for example, statistics, natural sciences, and social sciences. Risk analysis approaches and methods are also commonly used, but risk analysis is not broadly accepted as a science in itself. A key problem is the lack of explanatory power and large uncertainties when assessing risk. This article presents an emerging new risk analysis science based on novel ideas and theories on risk analysis developed in recent years by the risk analysis community. It builds on a fundamental change in thinking, from the search for accurate predictions and risk estimates, to knowledge generation related to concepts, theories, frameworks, approaches, principles, methods, and models to understand, assess, characterize, communicate, and (in a broad sense) manage risk. Examples are used to illustrate the importance of this distinct/separate risk analysis science for solving risk problems, supporting science in general and other disciplines in particular. © 2016 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.

  16. A life cycle cost analysis framework for geologic storage of hydrogen : a user's tool.

    Energy Technology Data Exchange (ETDEWEB)

    Kobos, Peter Holmes; Lord, Anna Snider; Borns, David James; Klise, Geoffrey T.

    2011-09-01

    The U.S. Department of Energy (DOE) has an interest in large scale hydrogen geostorage, which could offer substantial buffer capacity to meet possible disruptions in supply or changing seasonal demands. The geostorage site options being considered are salt caverns, depleted oil/gas reservoirs, aquifers and hard rock caverns. The DOE has an interest in assessing the geological, geomechanical and economic viability for these types of geologic hydrogen storage options. This study has developed an economic analysis methodology and subsequent spreadsheet analysis to address costs entailed in developing and operating an underground geologic storage facility. This year the tool was updated specifically to (1) incorporate more site-specific model input assumptions for the wells and storage site modules, (2) develop a version that matches the general format of the HDSAM model developed and maintained by Argonne National Laboratory, and (3) incorporate specific demand scenarios illustrating the model's capability. Four general types of underground storage were analyzed: salt caverns, depleted oil/gas reservoirs, aquifers, and hard rock caverns/other custom sites. Due to the substantial lessons learned from the geological storage of natural gas already employed, these options present a potentially sizable storage option. Understanding and including these various geologic storage types in the analysis physical and economic framework will help identify what geologic option would be best suited for the storage of hydrogen. It is important to note, however, that existing natural gas options may not translate to a hydrogen system where substantial engineering obstacles may be encountered. There are only three locations worldwide that currently store hydrogen underground and they are all in salt caverns. Two locations are in the U.S. (Texas), and are managed by ConocoPhillips and Praxair (Leighty, 2007). The third is in Teeside, U.K., managed by Sabic Petrochemicals (Crotogino

  17. Chemical analysis and potential health risks of hookah charcoal

    Energy Technology Data Exchange (ETDEWEB)

    Elsayed, Yehya, E-mail: yelsayed@aus.edu; Dalibalta, Sarah, E-mail: sdalibalta@aus.edu; Abu-Farha, Nedal

    2016-11-01

    Hookah (waterpipe) smoking is a very common practice that has spread globally. There is growing evidence on the hazardous consequences of smoking hookah, with studies indicating that its harmful effects are comparable to cigarette smoking if not worse. Charcoal is commonly used as a heating source for hookah smoke. Although charcoal briquettes are thought to be one of the major contributors to toxicity, their composition and impact on the smoke generated remains largely unidentified. This study aims to analyze the elemental composition of five different raw synthetic and natural charcoals by using Carbon-Hydrogen-Nitrogen (CHN) analysis, inductively coupled plasma (ICP), and scanning electron microscopy coupled with energy dispersive X-Ray spectrometry (SEM-EDS). Elemental analysis showed that the raw charcoals contain heavy metals such as zinc, iron, cadmium, vanadium, aluminum, lead, chromium, manganese and cobalt at concentrations similar, if not higher than, cigarettes. In addition, thermal desorption-gas chromatography–mass spectrometry (TD-GC–MS) was used to analyze the chemical composition of the smoke produced from burning the charcoal samples. The smoke emitted from charcoal was found to be the source of numerous compounds which could be hazardous to health. A total of seven carcinogens, 39 central nervous system depressants and 31 respiratory irritants were identified. - Highlights: • Hookah charcoals, mainly synthetic brands, contains trace/heavy metals in concentrations exceeding those in cigarettes. • The concentration of lead in synthetic charcoal briquettes may impose adverse effects on human health. • The amount of nitrogen in synthetic charcoal is comparable to that reported in cigarettes. • Chemical profiling of smoke emitted from hookah charcoal reveals many compounds associated with potential health risks.

  18. Environmental risk analysis for nanomaterials: Review and evaluation of frameworks

    DEFF Research Database (Denmark)

    Grieger, Khara Deanne; Linkov, Igor; Hansen, Steffen Foss

    2012-01-01

    In response to the challenges of conducting traditional human health and ecological risk assessment for nanomaterials (NM), a number of alternative frameworks have been proposed for NM risk analysis. This paper evaluates various risk analysis frameworks proposed for NM based on a number of criteria...... to occupational settings with minor environmental considerations, and most have not been thoroughly tested on a wide range of NM. Care should also be taken when selecting the most appropriate risk analysis strategy for a given risk context. Given this, we recommend a multi-faceted approach to assess...... the environmental risks of NM as well as increased applications and testing of the proposed frameworks for different NM....

  19. Liquid Hydrogen Regulated Low Pressure High Flow Pneumatic Panel AFT Arrow Analysis

    Science.gov (United States)

    Jones, Kelley, M.

    2013-01-01

    Project Definition: Design a high flow pneumatic regulation panel to be used with helium and hydrogen. The panel will have two circuits, one for gaseous helium (GHe) supplied from the GHe Movable Storage Units (MSUs) and one for gaseous hydrogen (GH2) supplied from an existing GH2 Fill Panel. The helium will supply three legs; to existing panels and on the higher pressure leg and Simulated Flight Tanks (SFTs) for the lower pressure legs. The hydrogen line will pressurize a 33,000 gallon vacuum jacketed vessel.

  20. HANFORD SAFETY ANALYSIS & RISK ASSESSMENT HANDBOOK (SARAH)

    Energy Technology Data Exchange (ETDEWEB)

    EVANS, C B

    2004-12-21

    The purpose of the Hanford Safety Analysis and Risk Assessment Handbook (SARAH) is to support the development of safety basis documentation for Hazard Category 2 and 3 (HC-2 and 3) U.S. Department of Energy (DOE) nuclear facilities to meet the requirements of 10 CFR 830, ''Nuclear Safety Management''. Subpart B, ''Safety Basis Requirements.'' Consistent with DOE-STD-3009-94, Change Notice 2, ''Preparation Guide for U.S. Department of Energy Nonreactor Nuclear Facility Documented Safety Analyses'' (STD-3009), and DOE-STD-3011-2002, ''Guidance for Preparation of Basis for Interim Operation (BIO) Documents'' (STD-3011), the Hanford SARAH describes methodology for performing a safety analysis leading to development of a Documented Safety Analysis (DSA) and derivation of Technical Safety Requirements (TSR), and provides the information necessary to ensure a consistently rigorous approach that meets DOE expectations. The DSA and TSR documents, together with the DOE-issued Safety Evaluation Report (SER), are the basic components of facility safety basis documentation. For HC-2 or 3 nuclear facilities in long-term surveillance and maintenance (S&M), for decommissioning activities, where source term has been eliminated to the point that only low-level, residual fixed contamination is present, or for environmental remediation activities outside of a facility structure, DOE-STD-1120-98, ''Integration of Environment, Safety, and Health into Facility Disposition Activities'' (STD-1120), may serve as the basis for the DSA. HC-2 and 3 environmental remediation sites also are subject to the hazard analysis methodologies of this standard.

  1. Insurability of Cyber Risk: An Empirical Analysis

    OpenAIRE

    Biener, Christian; Eling, Martin; Wirfs, Jan Hendrik

    2015-01-01

    This paper discusses the adequacy of insurance for managing cyber risk. To this end, we extract 994 cases of cyber losses from an operational risk database and analyse their statistical properties. Based on the empirical results and recent literature, we investigate the insurability of cyber risk by systematically reviewing the set of criteria introduced by Berliner (1982). Our findings emphasise the distinct characteristics of cyber risks compared with other operational risks and bring to li...

  2. Integration of risk analysis, land use planning, and cost analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rajen, G.; Sanchez, G.

    1994-12-31

    The Department of Energy (DOE) and the Pueblo of San Ildefonso (Pueblo), which is a sovereign Indian tribe, have often been involved in adversarial situations regarding the Los Alamos National Laboratory (LANL). The Pueblo shares a common boundary with the LANL. This paper describes an on-going project that could alter the DOE and the Pueblo`s relationship to one of cooperation; and unite the DOE and the Pueblo in a Pollution Prevention/Waste Minimization, and Integrated Risk Analysis and Land Use Planning effort.

  3. Manufacturing Cost Analysis of Novel Steel/Concrete Composite Vessel for Stationary Storage of High-Pressure Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Zhili [ORNL; Zhang, Wei [ORNL; Wang, Jy-An John [ORNL; Ren, Fei [ORNL

    2012-09-01

    A novel, low-cost, high-pressure, steel/concrete composite vessel (SCCV) technology for stationary storage of compressed gaseous hydrogen (CGH2) is currently under development at Oak Ridge National Laboratory (ORNL) sponsored by DOE s Fuel Cell Technologies (FCT) Program. The SCCV technology uses commodity materials including structural steels and concretes for achieving cost, durability and safety requirements. In particular, the hydrogen embrittlement of high-strength low-alloy steels, a major safety and durability issue for current industry-standard pressure vessel technology, is mitigated through the use of a unique layered steel shell structure. This report presents the cost analysis results of the novel SCCV technology. A high-fidelity cost analysis tool is developed, based on a detailed, bottom-up approach which takes into account the material and labor costs involved in each of the vessel manufacturing steps. A thorough cost study is performed to understand the SCCV cost as a function of the key vessel design parameters, including hydrogen pressure, vessel dimensions, and load-carrying ratio. The major conclusions include: The SCCV technology can meet the technical/cost targets set forth by DOE s FCT Program for FY2015 and FY2020 for all three pressure levels (i.e., 160, 430 and 860 bar) relevant to the hydrogen production and delivery infrastructure. Further vessel cost reduction can benefit from the development of advanced vessel fabrication technologies such as the highly automated friction stir welding (FSW). The ORNL-patented multi-layer, multi-pass FSW can not only reduce the amount of labor needed for assembling and welding the layered steel vessel, but also make it possible to use even higher strength steels for further cost reductions and improvement of vessel structural integrity. It is noted the cost analysis results demonstrate the significant cost advantage attainable by the SCCV technology for different pressure levels when compared to the

  4. The market viability of nuclear hydrogen technologies.

    Energy Technology Data Exchange (ETDEWEB)

    Botterud, A.; Conzelmann, G.; Petri, M. C.; Yildiz, B.

    2007-04-06

    The Department of Energy Office of Nuclear Energy is supporting system studies to gain a better understanding of nuclear power's potential role in a hydrogen economy and what hydrogen production technologies show the most promise. This assessment includes identifying commercial hydrogen applications and their requirements, comparing the characteristics of nuclear hydrogen systems to those market requirements, evaluating nuclear hydrogen configuration options within a given market, and identifying the key drivers and thresholds for market viability of nuclear hydrogen options. One of the objectives of the current analysis phase is to determine how nuclear hydrogen technologies could evolve under a number of different futures. The outputs of our work will eventually be used in a larger hydrogen infrastructure and market analysis conducted for DOE-EE using a system-level market simulation tool now underway. This report expands on our previous work by moving beyond simple levelized cost calculations and looking at profitability, risk, and uncertainty from an investor's perspective. We analyze a number of technologies and quantify the value of certain technology and operating characteristics. Our model to assess the profitability of the above technologies is based on Real Options Theory and calculates the discounted profits from investing in each of the production facilities. We use Monte-Carlo simulations to represent the uncertainty in hydrogen and electricity prices. The model computes both the expected value and the distribution of discounted profits from a production plant. We also quantify the value of the option to switch between hydrogen and electricity production in order to maximize investor profits. Uncertainty in electricity and hydrogen prices can be represented with two different stochastic processes: Geometric Brownian Motion (GBM) and Mean Reversion (MR). Our analysis finds that the flexibility to switch between hydrogen and electricity leads

  5. 49 CFR 260.17 - Credit risk premium analysis.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Credit risk premium analysis. 260.17 Section 260... Financial Assistance § 260.17 Credit risk premium analysis. (a) When Federal appropriations are not available to cover the total subsidy cost, the Administrator will determine the Credit Risk Premium...

  6. [Risk factors for preeclampsia. Multivariate analysis].

    Science.gov (United States)

    González, A L; Ulloa Galván, G; Alpuche, G; Romero Arauz, J F

    2000-08-01

    To determine in multivariate analysis the clinical, social, and demographic factors for preeclampsia. A case-control study was designed. Three hundred patients were included, divided in two groups. 150 cases with criteria diagnosis for preeclampsia. 150 patients with normal pregnancy and deliveries. The main variables analyzed were age, schooling, marital status, employment, socioeconomic status, smoking and alcohol consumption, body mass index, familiar history of preeclampsia, history of preeclampsia in previous pregnancy, parity and type of pregnancy (single or multiple). For comparison of cases and controls on categorical variables, odds ratios and 95% confidence intervals were calculated, and multiple logistic regression analyses. Multiple logistic regression analysis showed that history of preeclampsia in previous pregnancy has OR 23.7, 95% p < 0.001, familiar history of preeclampsia OR 1.62, p < 0.08, high body mass has OR 1.60. The knowledge of the most important risk factors in our population could be useful for the clinical to pre-detect the patient who will develop preeclampsia.

  7. Analysis of conformational changes in rhodopsin by histidine hydrogen-deuterium exchange.

    Science.gov (United States)

    Lodowski, David T; Miyagi, Masaru

    2015-01-01

    Hydrogen-deuterium exchange (HDX) is a technique that measures the exchange of protein hydrogens for deuteriums in a D2O-containing buffer, providing readout of the structural dynamics. Histidine hydrogen-deuterium exchange mass spectrometry (His-HDX-MS) is a variation of this technique that measures the slow HDX of imidazole C2 hydrogens of histidines. This measurement, when accompanied by pH titration, provides both pK as and half-lives (t 1/2) of the HDX reaction for individual histidine residues in proteins. The pK a and t 1/2 values indicate the electrostatic environment and the degree of side-chain solvent accessibility of the histidine residues, respectively. Herein we describe an experimental protocol to characterize rhodopsin by His-HDX-MS. This technique can be used to monitor different states of rhodopsin and might be useful for monitoring longtime scale events in other GPCRs.

  8. Theoretical analysis and semianalytical solutions for a turbulent buoyant hydrogen-air jet

    KAUST Repository

    El-Amin, Mohamed

    2012-01-01

    Semianalytical solutions are developed for turbulent hydrogen-air plume. We derived analytical expressions for plume centerline variables (radius, velocity, and density deficit) in terms of a single universal function, called plume function. By combining the obtained analytical expressions of centerline variables with empirical Gaussian expressions of the mean variables, we obtain semianalytical expressions for mean quantities of hydrogen-air plume (velocity, density deficit, and mass fraction).

  9. Trace component analysis of process hydrogen streams at the Wilsonville Advanced Coal Liquefaction Facility

    Energy Technology Data Exchange (ETDEWEB)

    Bronfenbrenner, J.C.

    1983-09-01

    This report summarizes subcontracted work done by the Radian Corporation to analyze trace components in process hydrogen streams at the Advanced Coal Liquefaction Facility in Wilsonville, Alabama. The data will be used to help define whether the gas streams to be treated in the hydrogen processing unit in the SRC-I Demonstration Plant will require further treatment to remove trace contaminants that could be explosive under certain conditions. 2 references.

  10. Kinetic analysis on photocatalytic degradation of gaseous acetaldehyde, ammonia and hydrogen sulfide on nanosized porous TiO2 films

    Directory of Open Access Journals (Sweden)

    Iis Sopyan

    2007-01-01

    Full Text Available The characteristics of the UV illumination-assisted degradation of gaseous acetaldehyde, hydrogen sulfide, and ammonia on highly active nanostructured-anatase and rutile films were investigated. It was found that the anatase film showed a higher photocatalytic activity than the counterpart did, however, the magnitude of difference in the photocatalytic activity of both films decreased in the order ammonia>acetaldehyde>hydrogen sulfide. To elucidate the reasons for the observation, the adsorption characteristics and the kinetics of photocatalytic degradation of the three reactants on both films were analyzed. The adsorption analysis examined using a simple Langmuir isotherm, showed that adsorbability on both films decreased in the order ammonia>acetaldehyde>hydrogen sulfide, which can be explained in terms of the decreasing electron-donor capacity. Acetaldehyde and ammonia adsorbed more strongly and with higher coverage on anatase film (1.2 and 5.6 molecules/nm2, respectively than on rutile (0.6 and 4.7 molecules/nm2, respectively. Conversely, hydrogen sulfide molecules adsorbed more strongly on rutile film (0.7 molecules/nm2 than on anatase (0.4 molecules/nm2. Exposure to UV light illumination brought about the photocatalytic oxidation of the three gases in contact with both TiO2 films, and the decrease in concentration were measured, and their kinetics are analyzed in terms of the Langmuir–Hinshelwood kinetic model. From the kinetic analysis, it was found that the anatase film showed the photocatalytic activities that were factors of ~8 and ~5 higher than the rutile film for the degradation of gaseous ammonia and acetaldehyde, respectively. However, the activity was only a factor of ~1.5 higher for the photodegradation of hydrogen sulfide. These observations are systematically explained by the charge separation efficiency and the adsorption characteristics of each catalyst as well as by the physical and electrochemical properties of each

  11. The hydrogen resource. Productive, technical and economic analysis; La risorsa idrogeno: analisi produttiva tecnica ed economica

    Energy Technology Data Exchange (ETDEWEB)

    De Fronzo, G. [Lecce Univ., Lecce (Italy). Dipt. di Scienze Economiche, Matematico-Statistiche, Economici-Aziendali

    2000-02-01

    Diffusion of hydrogen as an energetic vector meets with a lot of obstacles that don't depend on available raw material, but on hydrogen combination with other elements. It is necessary, therefore, to separate hydrogen picking out the available different technologies to have different pure hydrogen of variable quantities. Besides, its diffusion as fuel is limited because of the great production cost compared to fuels sprung from petroleum. Hydrogen used on a large scale could have advantages on the environment and occupation, but there are economic and politic obstacles to limit its diffusion. Future of economic system, based on hydrogen as the main energetic vector, will depend on the programme that national and international qualified governing bodies will be able to do. [Italian] L'articolo analizza l'uso dell'idrogeno come risorsa dal punto di vista tecnico ed economico. Si discute la relazione con i programmi che governi nazionali sapranno mettere in campo per il suo sfruttamento.

  12. Multiple Sclerosis Increases Fracture Risk: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Guixian Dong

    2015-01-01

    Full Text Available Purpose. The association between multiple sclerosis (MS and fracture risk has been reported, but results of previous studies remain controversial and ambiguous. To assess the association between MS and fracture risk, a meta-analysis was performed. Method. Based on comprehensive searches of the PubMed, Embase, and Web of Science, we identified outcome data from all articles estimating the association between MS and fracture risk. The pooled risk ratios (RRs with 95% confidence intervals (CIs were calculated. Results. A significant association between MS and fracture risk was found. This result remained statistically significant when the adjusted RRs were combined. Subgroup analysis stratified by the site of fracture suggested significant associations between MS and tibia fracture risk, femur fracture risk, hip fracture risk, pelvis fracture risk, vertebrae fracture risk, and humerus fracture risk. In the subgroup analysis by gender, female MS patients had increased fracture risk. When stratified by history of drug use, use of antidepressants, hypnotics/anxiolytics, anticonvulsants, and glucocorticoids increased the risk of fracture risk in MS patients. Conclusions. This meta-analysis demonstrated that MS was significantly associated with fracture risk.

  13. Managing Software Project Risks (Analysis Phase) with Proposed Fuzzy Regression Analysis Modelling Techniques with Fuzzy Concepts

    OpenAIRE

    Elzamly, Abdelrafe; Hussin, Burairah

    2014-01-01

    The aim of this paper is to propose new mining techniques by which we can study the impact of different risk management techniques and different software risk factors on software analysis development projects. The new mining technique uses the fuzzy multiple regression analysis techniques with fuzzy concepts to manage the software risks in a software project and mitigating risk with software process improvement. Top ten software risk factors in analysis phase and thirty risk management techni...

  14. Structural reliability analysis applied to pipeline risk analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gardiner, M. [GL Industrial Services, Loughborough (United Kingdom); Mendes, Renato F.; Donato, Guilherme V.P. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2009-07-01

    Quantitative Risk Assessment (QRA) of pipelines requires two main components to be provided. These are models of the consequences that follow from some loss of containment incident, and models for the likelihood of such incidents occurring. This paper describes how PETROBRAS have used Structural Reliability Analysis for the second of these, to provide pipeline- and location-specific predictions of failure frequency for a number of pipeline assets. This paper presents an approach to estimating failure rates for liquid and gas pipelines, using Structural Reliability Analysis (SRA) to analyze the credible basic mechanisms of failure such as corrosion and mechanical damage. SRA is a probabilistic limit state method: for a given failure mechanism it quantifies the uncertainty in parameters to mathematical models of the load-resistance state of a structure and then evaluates the probability of load exceeding resistance. SRA can be used to benefit the pipeline risk management process by optimizing in-line inspection schedules, and as part of the design process for new construction in pipeline rights of way that already contain multiple lines. A case study is presented to show how the SRA approach has recently been used on PETROBRAS pipelines and the benefits obtained from it. (author)

  15. Technical Overview of Ecological Risk Assessment - Analysis Phase: Exposure Characterization

    Science.gov (United States)

    Exposure Characterization is the second major component of the analysis phase of a risk assessment. For a pesticide risk assessment, the exposure characterization describes the potential or actual contact of a pesticide with a plant, animal, or media.

  16. Advanced Risk Analysis for High-Performing Organizations

    National Research Council Canada - National Science Library

    Alberts, Christopher; Dorofee, Audrey

    2006-01-01

    ...) are not readily identified using traditional risk analysis techniques. High-performing organizations have the basic skills needed to identify and manage these new types of risk, but lack sufficient techniques...

  17. Hydrogen sensor

    Science.gov (United States)

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  18. Putting problem formulation at the forefront of GMO risk analysis.

    Science.gov (United States)

    Tepfer, Mark; Racovita, Monica; Craig, Wendy

    2013-01-01

    When applying risk assessment and the broader process of risk analysis to decisions regarding the dissemination of genetically modified organisms (GMOs), the process has a tendency to become remarkably complex. Further, as greater numbers of countries consider authorising the large-scale dissemination of GMOs, and as GMOs with more complex traits reach late stages of development, there has been increasing concern about the burden posed by the complexity of risk analysis. We present here an improved approach for GMO risk analysis that gives a central role to problem formulation. Further, the risk analysis strategy has been clarified and simplified in order to make rigorously scientific risk assessment and risk analysis more broadly accessible to diverse stakeholder groups.

  19. DATA COLLECTION, QUALITY ASSURANCE, AND ANALYSIS PLAN FOR THE 2008/2009 HYDROGEN AND FUEL CELLS KNOWLEDGE AND OPINIONS SURVEYS

    Energy Technology Data Exchange (ETDEWEB)

    Schmoyer, Richard L [ORNL; Truett, Lorena Faith [ORNL; Diegel, Susan W [ORNL

    2008-09-01

    The 2008/2009 Knowledge and Opinions Survey, conducted for the Department of Energy's Hydrogen Program will measure the levels of awareness and understanding of hydrogen and fuel cell technologies within five target populations: (1) the general public, (2) students, (3) personnel in state and local governments, (4) potential end users of hydrogen fuel and fuel cell technologies in business and industry, and (5) safety and code officials. The ultimate goal of the surveys is a statistically valid, nationally based assessment. Distinct information collections are required for each of the target populations. Each instrument for assessing baseline knowledge is targeted to the corresponding population group. While many questions are identical across all populations, some questions are unique to each respondent group. The biggest data quality limitation of the hydrogen survey data (at least of the general public and student components) will be nonresponse bias. To ensure as high a response rate as possible, various measures will be taken to minimize nonresponse, including automated callbacks, cycling callbacks throughout the weekdays, and availability of Spanish speaking interviewers. Statistical adjustments (i.e., sampling weights) will also be used to account for nonresponse and noncoverage. The primary objective of the data analysis is to estimate the proportions of target population individuals who would respond to the questions in the various possible ways. Data analysis will incorporate necessary adjustments for the sampling design and sampling weights (i.e., probability sampling). Otherwise, however, the analysis will involve standard estimates of proportions of the interviewees responding in various ways to the questions. Sample-weight-adjusted contingency table chi-square tests will also be computed to identify differences between demographic groups The first round of Knowledge and Opinions Surveys was conducted in 2004. Analysis of these surveys produced a

  20. Hydrogen as an energy vector

    OpenAIRE

    Valenzuela Ortega, Daniel

    2013-01-01

    Study of the use of the Hydrogen to storage big amounts of energy. In this project there will be an study about the different energies that are profitable to use them to obtain hydrogen, the study of the different technologies to obtain hydrogen (electrolysis, gasification, etc.), the study of the technologies for storage the hydrogen and the study of the different ways to obtain final energy with the hydrogen. There will be also an overall analysis of the efficiency of the process a...

  1. Techno-economic analysis of stand-alone photovoltaic/wind/battery/hydrogen systems for very small-scale applications

    Directory of Open Access Journals (Sweden)

    Stojković Saša M.

    2016-01-01

    Full Text Available The paper presents the results of a technical and economic analysis of three stand-alone hybrid power systems based on renewable energy sources which supply a specific group of low-power consumers. This particular case includes measuring sensors and obstacle lights on a meteorological mast for wind measurements requiring an uninterrupted power supply in cold climate conditions. Although these low-power (100 W measuring sensors and obstacle lights use little energy, their energy consumption is not the same as the available solar energy obtained on a daily or seasonal basis. In the paper, complementarity of renewable energy sources was analysed, as well as one of short-term lead-acid battery-based storage and seasonal, hydrogen-based (electrolyser, H2 tank, and fuel cells storage. These relatively complex power systems were proposed earlier for high-power consumers only, while this study specifically highlights the role of the hydrogen system for supplying low-power consumers. The analysis employed a numerical simulation method using the HOMER software tool. The results of the analysis suggest that solar and wind-solar systems, which involve meteorological conditions as referred to in this paper, include a relatively large number of lead-acid batteries. Additionally, the analysis suggests that the use of hydrogen power systems for supplying low power-consumers is entirely justifiable, as it significantly reduces the number of batteries (two at minimum in this particular case. It was shown that the increase in costs induced by the hydrogen system is acceptable.

  2. Hazards Induced by Breach of Liquid Rocket Fuel Tanks: Conditions and Risks of Cryogenic Liquid Hydrogen-Oxygen Mixture Explosions

    CERN Document Server

    Osipov, Viatcheslav; Hafiychuk, Halyna; Ponizovskaya-Devine, Ekaterina; Smelyanskiy, Vadim; Mathias, Donovan; Lawrence, Scott; Werkheiser, Mary

    2010-01-01

    We analyze the data of purposeful rupture experiments with LOx and LH2 tanks, the Hydrogen-Oxygen Vertical Impact (HOVI) tests that were performed to clarify the ignition mechanisms, the explosive power of cryogenic H2/Ox mixtures under different conditions, and to elucidate the puzzling source of the initial formation of flames near the intertank section during the Challenger disaster. We carry out a physics-based analysis of general explosions scenarios for cryogenic gaseous H2/Ox mixtures and determine their realizability conditions, using the well-established simplified models from the detonation and deflagration theory. We study the features of aerosol H2/Ox mixture combustion and show, in particular, that aerosols intensify the deflagration flames and can induce detonation for any ignition mechanism. We propose a cavitation-induced mechanism of self-ignition of cryogenic H2/Ox mixtures that may be realized when gaseous H2 and Ox flows are mixed with a liquid Ox turbulent stream, as occurred in all HOVI ...

  3. Functional analysis of a novel hydrogen peroxide resistance gene in Lactobacillus casei strain Shirota.

    Science.gov (United States)

    Serata, Masaki; Kiwaki, Mayumi; Iino, Tohru

    2016-11-01

    Lactic acid bacteria have a variety of mechanisms for tolerance to oxygen and reactive oxygen species, and these mechanisms differ among species. Lactobacillus casei strain Shirota grows well under aerobic conditions, indicating that the various systems involved in oxidative stress resistance function in this strain. To elucidate the mechanism of oxidative stress resistance in L. casei strain Shirota, we examined the transcriptome response to oxygen or hydrogen peroxide exposure. We then focused on an uncharacterized gene that was found to be up-regulated by both oxygen and hydrogen peroxide stress; we named the gene hprA1 (hydrogen peroxide resistance gene). This gene is widely distributed among lactobacilli. We investigated the involvement of this gene in oxidative stress resistance, as well as the mechanism of tolerance to hydrogen peroxide. Growth of L. casei MS105, an hprA1-disrupted mutant, was not affected by oxygen stress, whereas the survival rate of MS105 after hydrogen peroxide treatment was markedly reduced compared to that of the wild-type. However, the activity of MS105 in eliminating hydrogen peroxide was similar to that of the wild-type. We cloned hprA1 from L. caseiShirota and purified recombinant HprA1 protein from Escherichia coli. We demonstrated that the recombinant HprA1 protein bound to iron and prevented the formation of a hydroxyl radical in vitro. Thus, HprA1 protein probably contributes to hydrogen peroxide tolerance in L. casei strain Shirota by binding to iron in the cells and preventing the formation of a hydroxyl radical.

  4. Computational Aspects of Dam Risk Analysis: Findings and Challenges

    Directory of Open Access Journals (Sweden)

    Ignacio Escuder-Bueno

    2016-09-01

    Full Text Available In recent years, risk analysis techniques have proved to be a useful tool to inform dam safety management. This paper summarizes the outcomes of three themes related to dam risk analysis discussed in the Benchmark Workshops organized by the International Commission on Large Dams Technical Committee on “Computational Aspects of Analysis and Design of Dams.” In the 2011 Benchmark Workshop, estimation of the probability of failure of a gravity dam for the sliding failure mode was discussed. Next, in 2013, the discussion focused on the computational challenges of the estimation of consequences in dam risk analysis. Finally, in 2015, the probability of sliding and overtopping in an embankment was analyzed. These Benchmark Workshops have allowed a complete review of numerical aspects for dam risk analysis, showing that risk analysis methods are a very useful tool to analyze the risk of dam systems, including downstream consequence assessments and the uncertainty of structural models.

  5. Automating risk analysis of software design models.

    Science.gov (United States)

    Frydman, Maxime; Ruiz, Guifré; Heymann, Elisa; César, Eduardo; Miller, Barton P

    2014-01-01

    The growth of the internet and networked systems has exposed software to an increased amount of security threats. One of the responses from software developers to these threats is the introduction of security activities in the software development lifecycle. This paper describes an approach to reduce the need for costly human expertise to perform risk analysis in software, which is common in secure development methodologies, by automating threat modeling. Reducing the dependency on security experts aims at reducing the cost of secure development by allowing non-security-aware developers to apply secure development with little to no additional cost, making secure development more accessible. To automate threat modeling two data structures are introduced, identification trees and mitigation trees, to identify threats in software designs and advise mitigation techniques, while taking into account specification requirements and cost concerns. These are the components of our model for automated threat modeling, AutSEC. We validated AutSEC by implementing it in a tool based on data flow diagrams, from the Microsoft security development methodology, and applying it to VOMS, a grid middleware component, to evaluate our model's performance.

  6. Automating Risk Analysis of Software Design Models

    Directory of Open Access Journals (Sweden)

    Maxime Frydman

    2014-01-01

    Full Text Available The growth of the internet and networked systems has exposed software to an increased amount of security threats. One of the responses from software developers to these threats is the introduction of security activities in the software development lifecycle. This paper describes an approach to reduce the need for costly human expertise to perform risk analysis in software, which is common in secure development methodologies, by automating threat modeling. Reducing the dependency on security experts aims at reducing the cost of secure development by allowing non-security-aware developers to apply secure development with little to no additional cost, making secure development more accessible. To automate threat modeling two data structures are introduced, identification trees and mitigation trees, to identify threats in software designs and advise mitigation techniques, while taking into account specification requirements and cost concerns. These are the components of our model for automated threat modeling, AutSEC. We validated AutSEC by implementing it in a tool based on data flow diagrams, from the Microsoft security development methodology, and applying it to VOMS, a grid middleware component, to evaluate our model's performance.

  7. Risk Analysis and Risk Management in the Public Sector and in Public Auditing

    OpenAIRE

    László Domokos; Melinda Nyéki; Katalin Jakovác; Erzsébeth Németh; Csaba Hatvani

    2015-01-01

    The significance of organisational risk management has grown ostensibly during recent decades, and this is true regarding for-profit organisations and public entities alike. There are, however, unique traits that characterise risk analysis and risk management as applied in the public sector, both in terms of areas of application and execution. Being mandatory is the foremost feature of risk management as applied in the public sector, with efforts to minimise risk, and the promotion of complia...

  8. The Born-Oppenheimer molecular simulations of infrared spectra of crystalline poly-(R)-3-hydroxybutyrate with analysis of weak Csbnd H⋯Odbnd C hydrogen bonds

    Science.gov (United States)

    Brela, Mateusz Z.; Boczar, Marek; Wójcik, Marek J.; Sato, Harumi; Nakajima, Takahito; Ozaki, Yukihiro

    2017-06-01

    In this letter we present results of study of weak Csbnd H⋯Odbnd C hydrogen bonds of crystalline poly-(R)-3-hydroxybutyrate (PHB) by using Born-Oppenheimer molecular dynamics. The polymeric structure and IR spectra of PHB result from the presence of the weak hydrogen bonds. We applied the post-molecular dynamics analysis to consider a Cdbnd O motion as indirectly involved in the hydrogen bonds. Quantization of the nuclear motion of the oxygens was done to perform detailed analysis of the strength and properties of the Cdbnd O bands involved in the weak hydrogen bonds. We have also shown the dynamic character of the weak hydrogen bond interactions.

  9. Communicating Coastal Risk Analysis in an Age of Climate Change

    Science.gov (United States)

    2011-10-01

    Coastal Risk Analysis in an Age of Climate Change TR-11-04 Brian Blanton, John McGee, Oleg Kapeljushnik Renaissance...TITLE AND SUBTITLE Communicating Coastal Risk Analysis in an Age of Climate Change 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Communicating Coastal Risk Analysis in an Age of Climate Change Brian Blanton, John

  10. Terrorism Risk Modeling for Intelligence Analysis and Infrastructure Protection

    Science.gov (United States)

    2007-01-01

    COVERED 00-00-2007 to 00-00-2007 4. TITLE AND SUBTITLE Terrorism Risk Modeling for Intelligence Analysis and Infrastructure Protection 5a...meet high standards for re- search quality and objectivity. Terrorism Risk Modeling for Intelligence Analysis and Infrastructure Protection Henry H...across differ- ent urban areas, to assess terrorism risks within a metropolitan area, and to target intelligence analysis and collection efforts. The

  11. An analysis of the explosion limits of hydrogen/oxygen mixtures with nonlinear chain reactions.

    Science.gov (United States)

    Liang, Wenkai; Law, Chung K

    2018-01-03

    The ignition boundary of hydrogen/oxygen mixtures is a Z-shaped curve in the pressure-temperature space, demonstrating the existence of three explosion limits. In this study, a general analysis governing all the three explosion limits in an isothermal environment is performed by considering both linear chain reactions (reactant-radical reactions) and nonlinear chain reactions (radical-radical reactions), in addition to the zeroth-order reactant-reactant reactions. For the nonlinear reactions, it is further shown that the linear-nonlinear coupling has the major influence, while the effect of nonlinear-nonlinear coupling is negligible. Phenomenologically, at low pressures, the competition between linear branching and linear termination as well as wall destruction determines the first and second explosion limits, while the nonlinear chain reactions are unimportant because of the small radical concentrations under these conditions. However, at higher pressures, both linear and nonlinear chain reactions are needed to accurately describe the third limit, which would be underpredicted by considering the linear chain reactions alone. For intermediate and high pressures, the dominant species are HO2 and H2O2, respectively. Mechanistically, the concentration of HO2 becomes higher at higher pressures due to the three-body recombination reaction, H + O2 + M → HO2 + M, such that the radical-radical reactions involving HO2 become important, while the reaction HO2 + HO2 → H2O2 + O2 renders HO2 nonessential at the third limit, with the H2O2 radical generated by the nonlinear chain reactions becoming the controlling species.

  12. Thermodynamic Analysis and Reduction of MnO2 by Methane-Hydrogen Gas Mixture

    Science.gov (United States)

    Liu, Bingbing; Zhang, Yuanbo; Su, Zijian; Peng, Zhiwei; Li, Guanghui; Jiang, Tao

    2017-09-01

    Methane and hydrogen reduction has emerged as promising technology for clean and efficient metallurgy. To understand the reduction process of MnO2 by CH4-H2 gas mixture, the effects of various CH4/(CH4 + H2) molar ratios (0-1) and temperatures (1100°C-1250°C) on the reduction of pure MnO2 were researched. Characterization of the solid carbon derived from the decomposition of CH4 gas was also determined. Thermodynamic analysis indicated that the MnO2 was first reduced to MnO by CH4-H2 gas mixture, and then MnO was reduced to Mn7C3 according to this reaction, 7MnO(s) + 10CH4(g) = Mn7C3(s) + 7CO(g) + 20H2(g). Experimental results showed that under the CH4/(CH4 + H2) molar ratio of 0.2, the reduction extent of MnO2 increased with the rising of temperatures. Nevertheless, the deep reduction of MnO to Mn7C3 was retarded even by increasing the temperature and prolonging the time, which was a result of the formation of deposited solid carbon. The free carbon contents in the reduced samples increased with the increasing of the CH4/(CH4 + H2) molar ratio and reduction time. The reduction of MnO2 and formation of carbon can be regulated by adjusting the CH4/(CH4 + H2) molar ratio in a gas mixture. For example, when MnO2 was reduced by 50 vol.%CH4-50%N2, large amounts of MnO and Mn7C3 particles were wrapped by the platelike and rodlike carbon with nanoscale. Yet, the wrapping phenomenon cannot be observed under 10 vol.%CH4-40 vol.%H2-50 vol.%N2.

  13. Global analysis of disulfide bond proteins in Pseudomonas aeruginosa exposed to hydrogen peroxide and gamma rays.

    Science.gov (United States)

    An, Byung Chull; Lee, Seung Sik; Lee, Eun Mi; Wi, Seung Gon; Park, Woojun; Chung, Byung Yeoup

    2010-05-01

    To isolate and characterise the oxidative stress-responsible disulfide bond proteins (DSBP) from Pseudomonas aeruginosa, under hydrogen peroxide (H(2)O(2)) and gamma ray-induced stress conditions. Oxidative stress in P. aeruginosa was induced by H(2)O(2) or (60)Co gamma-rays. DSBP of P. aeruginosa were isolated by using a thiol affinity purification method and liquid chromatography-mass spectrometry (LC-MS/MS). Induction of DSBP and their transcriptional levels were analysed by Western blot and quantitative-polymerase chain reaction (q-PCR), respectively. We isolated and identified 40 DSBP in P. aeruginosa. A comparison of DSBP patterns under different stress conditions, including exposure to 0.5 mM H(2)O(2) and 30 Gy of gamma rays, was carried out. We selected 13 DSBP based on their increased intensity under oxidative stress and investigated their expression levels using q-PCR. Of these 13 proteins, P. aeruginosa (PA) 0126 and PA0277 transcriptional levels were strongly induced (4- to 9-fold) by gamma ray. A corresponding induction in the translational levels of PA0126 was confirmed by Western blot analysis. PA0126 was identified is a hypothetical protein with 206 amino acids and contained three cysteine residues. A shift in molecular weight of PA0126 under oxidised/reduced state indicated its homo-oligomeric structure under non-reducing condition. PA0126, a hypothetical protein with disulfide bonds was identified as a key responder to oxidative stress along with other known DSBP of P. aeruginosa. We determined that all DSBP underwent a redox cycling. Furthermore, our results give deeper insight into the relationship between oxidative stress and DSBP in P. aeruginosa.

  14. Evaluating the risks of clinical research: direct comparative analysis.

    Science.gov (United States)

    Rid, Annette; Abdoler, Emily; Roberson-Nay, Roxann; Pine, Daniel S; Wendler, David

    2014-09-01

    Many guidelines and regulations allow children and adolescents to be enrolled in research without the prospect of clinical benefit when it poses minimal risk. However, few systematic methods exist to determine when research risks are minimal. This situation has led to significant variation in minimal risk judgments, raising concern that some children are not being adequately protected. To address this concern, we describe a new method for implementing the widely endorsed "risks of daily life" standard for minimal risk. This standard defines research risks as minimal when they do not exceed the risks posed by daily life activities or routine examinations. This study employed a conceptual and normative analysis, and use of an illustrative example. Different risks are composed of the same basic elements: Type, likelihood, and magnitude of harm. Hence, one can compare the risks of research and the risks of daily life by comparing the respective basic elements with each other. We use this insight to develop a systematic method, direct comparative analysis, for implementing the "risks of daily life" standard for minimal risk. The method offers a way of evaluating research procedures that pose the same types of risk as daily life activities, such as the risk of experiencing anxiety, stress, or other psychological harm. We thus illustrate how direct comparative analysis can be applied in practice by using it to evaluate whether the anxiety induced by a respiratory CO2 challenge poses minimal or greater than minimal risks in children and adolescents. Direct comparative analysis is a systematic method for applying the "risks of daily life" standard for minimal risk to research procedures that pose the same types of risk as daily life activities. It thereby offers a method to protect children and adolescents in research, while ensuring that important studies are not blocked because of unwarranted concerns about research risks.

  15. A DFT study and micro-kinetic analysis of acetylene selective hydrogenation on Pd-doped Cu(111) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ling-Ling [Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071 (China); Lv, Cun-Qin, E-mail: lcq173@126.com [College of Chemistry and Environmental Engineering, Shanxi Datong University, Datong 037009, Shanxi Province (China); Wang, Gui-Chang, E-mail: wangguichang@nankai.edu.cn [Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071 (China)

    2017-07-15

    Semi-hydrogenation of acetylene in a hydrogen-rich stream is an industrially important process. Inspired by the recent experiments that Cu(111) surface doped by a small number of Pd atoms can exhibit excellent catalytic performance toward the dissociation of H{sub 2} molecule as well as the high selective hydrogenation of acetylene as compared with pure Cu and Pd metal alone at low-temperature, here we performed systematic first-principles calculations to investigate the corresponding reaction mechanism related to the acetylene hydrogenation processes on single atom alloys (SAAs) and monolayer Pd/Cu(111) (i.e.,1.00 ML Pd/Cu(111)) model catalysts in detail, and to explore the possible factors controlling the high selectivity on SAAs. Our results clearly demonstrate that the SAA catalyst has higher selectivity for the ethylene formation than that of 1.00 ML Pd/Cu(111), and lower activity for the acetylene conversion compared with that of 1.00 ML Pd/Cu(111). The relatively high selectivity on SAA is mainly due to the facile desorption of ethylene and moderate activity in the dissociation of molecular H{sub 2}. The main factor which lowers the selectivity towards the ethylene formation on 1.00 ML Pd/Cu(111) is that this system has a higher capacity to promote the breaking of C−H/C−C bonds, which leads to the formation of carbonaceous deposits and polymers such as benzene, and thus reduces the selectivity for the ethylene formation. Meanwhile, it was found that the desorption energy of ethylene on these two surfaces was smaller than the energy barrier of further hydrogenation, which results in the absence of ethane on these two systems. Micro-kinetic model analysis provides a further valuable insight into the evidence for the key factors controlling the catalytic activity and selectivity towards the selective hydrogenation of acetylene. Our findings may help people to design a highly selective hydrogenation catalyst by controlling the balance between the H{sub 2

  16. A DFT study and micro-kinetic analysis of acetylene selective hydrogenation on Pd-doped Cu(111) surfaces

    Science.gov (United States)

    Ma, Ling-Ling; Lv, Cun-Qin; Wang, Gui-Chang

    2017-07-01

    Semi-hydrogenation of acetylene in a hydrogen-rich stream is an industrially important process. Inspired by the recent experiments that Cu(111) surface doped by a small number of Pd atoms can exhibit excellent catalytic performance toward the dissociation of H2 molecule as well as the high selective hydrogenation of acetylene as compared with pure Cu and Pd metal alone at low-temperature, here we performed systematic first-principles calculations to investigate the corresponding reaction mechanism related to the acetylene hydrogenation processes on single atom alloys (SAAs) and monolayer Pd/Cu(111) (i.e.,1.00 ML Pd/Cu(111)) model catalysts in detail, and to explore the possible factors controlling the high selectivity on SAAs. Our results clearly demonstrate that the SAA catalyst has higher selectivity for the ethylene formation than that of 1.00 ML Pd/Cu(111), and lower activity for the acetylene conversion compared with that of 1.00 ML Pd/Cu(111). The relatively high selectivity on SAA is mainly due to the facile desorption of ethylene and moderate activity in the dissociation of molecular H2. The main factor which lowers the selectivity towards the ethylene formation on 1.00 ML Pd/Cu(111) is that this system has a higher capacity to promote the breaking of Csbnd H/Csbnd C bonds, which leads to the formation of carbonaceous deposits and polymers such as benzene, and thus reduces the selectivity for the ethylene formation. Meanwhile, it was found that the desorption energy of ethylene on these two surfaces was smaller than the energy barrier of further hydrogenation, which results in the absence of ethane on these two systems. Micro-kinetic model analysis provides a further valuable insight into the evidence for the key factors controlling the catalytic activity and selectivity towards the selective hydrogenation of acetylene. Our findings may help people to design a highly selective hydrogenation catalyst by controlling the balance between the H2 dissociation and

  17. Analysis of the distribution of hydrogen in the containment drywell CN Cofrentes; Analisis de la distribucion de hidrogeno en contencion y pozo seco de C. N. Cofrentes

    Energy Technology Data Exchange (ETDEWEB)

    Molina, M. C.; Serrano, C.; Gonzalez, M.; Jimenez, G.; Lopez-Alonso, E.

    2014-07-01

    The development model of the containment CN Cofrentes by GOTHIC was carried out by introducing all geometric and Containment data structures, thus being able to model all the interior spaces and rooms that compose it. Thus we have obtained a detailed 3D model with sufficient accuracy to the global study of hydrogen management, allowing to take into account, when the distribution of hydrogen, both asymmetric containment as downloads mass and energy in it are made, allowing to simulate the distribution of steam and hydrogen present in the severe accident to determine the areas of greatest risk of deflagration or detonation during the evolution of the accident. (Author)

  18. Technical Rationale for Australian Computer Security Risk Analysis Guidelines

    Science.gov (United States)

    1992-06-01

    systems and products to be used for the electronic processing of National Security and/or Sensitive Material.... Computer security , Computer information security, Secure communications, Risk analysis.

  19. RISK ANALYSIS IN INFORMATION TECHNOLOGY AND COMMUNICATION OUTSOURCING

    Directory of Open Access Journals (Sweden)

    Edmir Parada Vasques Prado

    2011-12-01

    Full Text Available This research aims at evaluating the risk analysis process in Information Technology and Communication (ICT outsourcing conducted by organizations of the private sector. The research is characterized by being a descriptive, quantitative and transversal type study, which was used the survey method. Data were collected through questionnaire, the sample is not random and we used a convenience sampling process. The research made contributions to understanding the risk analysis process in ICT services outsourcing, and identified statistically significant relationships between risk analysis, organization's size and its industry, and between risk analysis and diversity of outsourced services

  20. A comparative analysis of risk and quality

    DEFF Research Database (Denmark)

    Lynette, Jennifer Elyse

    2017-01-01

    independently, decision making and judgement processes have the potential to be positively impacted by furthering research and developing a deeper understanding of these constructs. By understanding risk management principles and combining that with a quality systems approach, decision making can be improved......Within the field of emergency management and fire response, risk and quality are conceptualized to some degree in every response effort. Quality is viewed as a relatively new concept within the field of emergency management and fire response. Whereas, within this same field the concept of risk...... interest to the field of emergency management and fire response, includes the methods used by risk research to measure risk in the field, and how that concept can be utilized for future research focusing on quality in the same field. By analyzing the subjective assessments that involve risk and quality...

  1. A first principles analysis of the effect of hydrogen concentration in hydrogenated amorphous silicon on the formation of strained Si-Si bonds and the optical and mobility gaps

    Energy Technology Data Exchange (ETDEWEB)

    Legesse, Merid; Nolan, Michael, E-mail: Michael.nolan@tyndall.ie; Fagas, Giorgos, E-mail: Georgios.fagas@tyndall.ie [Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork (Ireland)

    2014-05-28

    In this paper, we use a model of hydrogenated amorphous silicon generated from molecular dynamics with density functional theory calculations to examine how the atomic geometry and the optical and mobility gaps are influenced by mild hydrogen oversaturation. The optical and mobility gaps show a volcano curve as the hydrogen content varies from undersaturation to mild oversaturation, with largest gaps obtained at the saturation hydrogen concentration. At the same time, mid-gap states associated with dangling bonds and strained Si-Si bonds disappear at saturation but reappear at mild oversaturation, which is consistent with the evolution of optical gap. The distribution of Si-Si bond distances provides the key to the change in electronic properties. In the undersaturation regime, the new electronic states in the gap arise from the presence of dangling bonds and strained Si-Si bonds, which are longer than the equilibrium Si-Si distance. Increasing hydrogen concentration up to saturation reduces the strained bonds and removes dangling bonds. In the case of mild oversaturation, the mid-gap states arise exclusively from an increase in the density of strained Si-Si bonds. Analysis of our structure shows that the extra hydrogen atoms form a bridge between neighbouring silicon atoms, thus increasing the Si-Si distance and increasing disorder in the sample.

  2. Market penetration analysis of hydrogen vehicles in Norwegian passenger transport towards 2050

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Eva; Fidje, Audun; Espegren, Kari Aamodt [Institute for Energy Technology, Energy Systems Department, P.O. Box 40, NO-2027 Kjeller (Norway); Stiller, Christoph [Department of Energy and Process Engineering, The Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Svensson, Ann Mari; Moeller-Holst, Steffen [Department of Energy Conversion and Materials, SINTEF Materials and Chemistry, NO-7465 Trondheim (Norway)

    2010-07-15

    The Norwegian energy system is characterized by high dependency on electricity, mainly hydro power. If the national targets to reduce emissions of greenhouse gases should be met, a substantial reduction of CO{sub 2} emissions has to be obtained from the transport sector. This paper presents the results of the analyses of three Norwegian regions with the energy system model MARKAL during the period 2005-2050. The MARKAL models were used in connection with an infrastructure model H2INVEST. The analyses show that a transition to a hydrogen fuelled transportation sector could be feasible in the long run, and indicate that with substantial hydrogen distribution efforts, fuel cell cars can become competitive compared to other technologies both in urban (2025) and rural areas (2030). In addition, the result shows the importance of the availability of local energy resources for hydrogen production, like the advantages of location close to chemical industry or surplus of renewable electricity. (author)

  3. National hydrogen technology competitiveness analysis with an integrated fuzzy AHP and TOPSIS approaches: In case of hydrogen production and storage technologies

    Science.gov (United States)

    Lee, Seongkon; Mogi, Gento

    2017-02-01

    The demand of fossil fuels, including oil, gas, and coal has been increasing with the rapid development of developing countries such as China and India. U.S., Japan, EU, and Korea have been making efforts to transfer to low carbon and green growth economics for sustainable development. And they also have been measuring to cope with climate change and the depletion of conventional fuels. Advanced nations implemented strategic energy technology development plans to lead the future energy market. Strategic energy technology development is crucial alternative to address the energy issues. This paper analyze the relative competitiveness of hydrogen energy technologies in case of hydrogen production and storage technologies from 2006 to 2010. Hydrogen energy technology is environmentally clean technology comparing with the previous conventional energy technologies and will play a key role to solve the greenhouse gas effect. Leading nations have increasingly focused on hydrogen technology R&D. This research is carried out the relative competitiveness of hydrogen energy technologies employed by an integrated fuzzy analytic hierarchy process (Fuzzy AHP) and The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) approaches. We make four criteria, accounting for technological status, R&D budget, R&D human resource, and hydrogen infra. This research can be used as fundamental data for implementing national hydrogen energy R&D planning for energy policy-makers.

  4. Analysis of the microbial community of the biocathode of a hydrogen-producing microbial electrolysis cell

    Energy Technology Data Exchange (ETDEWEB)

    Croese, Elsemiek; Pereira, Maria Alcina [Wageningen Univ. (Netherlands). Lab. of Microbiology; Wetsus, Centre of Excellence for Sustainable Water Technology, Leeuwarden (Netherlands); Euverink, Gert-Jan W. [Wetsus, Centre of Excellence for Sustainable Water Technology, Leeuwarden (Netherlands); Stams, Alfons J.M.; Geelhoed, Jeanine S. [Wageningen Univ. (Netherlands). Lab. of Microbiology

    2011-12-15

    The microbial electrolysis cell (MEC) is a promising system for hydrogen production. Still, expensive catalysts such as platinum are needed for efficient hydrogen evolution at the cathode. Recently, the possibility to use a biocathode as an alternative for platinum was shown. The microorganisms involved in hydrogen evolution in such systems are not yet identified. We analyzed the microbial community of a mixed culture biocathode that was enriched in an MEC bioanode. This biocathode produced 1.1 A m{sup -2} and 0.63 m{sup 3} H{sub 2} m{sup -3} cathode liquid volume per day. The bacterial population consisted of 46% Proteobacteria, 25% Firmicutes, 17% Bacteroidetes, and 12% related to other phyla. The dominant ribotype belonged to the species Desulfovibrio vulgaris. The second major ribotype cluster constituted a novel taxonomic group at the genus level, clustering within uncultured Firmicutes. The third cluster belonged to uncultured Bacteroidetes and grouped in a taxonomic group from which only clones were described before; most of these clones originated from soil samples. The identified novel taxonomic groups developed under environmentally unusual conditions, and this may point to properties that have not been considered before. A pure culture of Desulfovibrio strain G11 inoculated in a cathode of an MEC led to a current development from 0.17 to 0.76 A m{sup -2} in 9 days, and hydrogen gas formation was observed. On the basis of the known characteristics of Desulfovibrio spp., including its ability to produce hydrogen, we propose a mechanism for hydrogen evolution through Desulfovibrio spp. in a biocathode system. (orig.)

  5. Analysis of the microbial community of the biocathode of a hydrogen-producing microbial electrolysis cell.

    Science.gov (United States)

    Croese, Elsemiek; Pereira, Maria Alcina; Euverink, Gert-Jan W; Stams, Alfons J M; Geelhoed, Jeanine S

    2011-12-01

    The microbial electrolysis cell (MEC) is a promising system for hydrogen production. Still, expensive catalysts such as platinum are needed for efficient hydrogen evolution at the cathode. Recently, the possibility to use a biocathode as an alternative for platinum was shown. The microorganisms involved in hydrogen evolution in such systems are not yet identified. We analyzed the microbial community of a mixed culture biocathode that was enriched in an MEC bioanode. This biocathode produced 1.1 A m(-2) and 0.63 m3 H2 m(-3) cathode liquid volume per day. The bacterial population consisted of 46% Proteobacteria, 25% Firmicutes, 17% Bacteroidetes, and 12% related to other phyla. The dominant ribotype belonged to the species Desulfovibrio vulgaris. The second major ribotype cluster constituted a novel taxonomic group at the genus level, clustering within uncultured Firmicutes. The third cluster belonged to uncultured Bacteroidetes and grouped in a taxonomic group from which only clones were described before; most of these clones originated from soil samples. The identified novel taxonomic groups developed under environmentally unusual conditions, and this may point to properties that have not been considered before. A pure culture of Desulfovibrio strain G11 inoculated in a cathode of an MEC led to a current development from 0.17 to 0.76 A m(-2) in 9 days, and hydrogen gas formation was observed. On the basis of the known characteristics of Desulfovibrio spp., including its ability to produce hydrogen, we propose a mechanism for hydrogen evolution through Desulfovibrio spp. in a biocathode system.

  6. Integration of phase change materials in compressed hydrogen gas systems: Modelling and parametric analysis

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Rothuizen, Erasmus; Jørgensen, Jens-Erik

    2016-01-01

    A dynamic fueling model is built to simulate the fueling process of a hydrogen tank with an integrated passive cooling system. The study investigates the possibility of absorbing a part of the heat of compression in the high latent-heat material during melting, with the aim of saving the monetary...... temperature. Results show that a 10-mm-thick layer of paraffin wax can absorb enough heat to reduce the adiabatic temperature by 20 K when compared to a standard Type IV tank, but its influence on the hydrogen peak temperature that occurs at the end of refueling is modest. The heat transfer from the gas...

  7. Numerical analysis of hydrogen and methane propagation during testing of combustion engines

    Directory of Open Access Journals (Sweden)

    Dvořák V.

    2007-10-01

    Full Text Available The research of gas-fuelled combustion engines using hydrogen or methane require accordingly equipped test benches which take respect to the higher dangerous of self ignition accidents. This article deals with numerical calculations of flow in laboratory during simulated leakage of gas-fuel from fuel system of tested engine. The influences of local suction and influences of roof exhausters on the flow in the laboratory and on the gas propagation are discussed. Results obtained for hydrogen and for methane are compared. Conclusions for design and performance of suction devices and test benches are deduced from these results.

  8. Final design, fluid dynamic and structural mechanical analysis of a liquid hydrogen Moderator for the European Spallation Source

    Science.gov (United States)

    Bessler, Y.; Henkes, C.; Hanusch, F.; Schumacher, P.; Natour, G.; Butzek, M.; Klaus, M.; Lyngh, D.; Kickulies, M.

    2017-02-01

    The European Spallation Source (ESS) is currently in the construction phase and should have first beam on Target in 2019. ESS, located in Sweden, will be the most powerful spallation neutron source worldwide, with the goal to produce neutrons for research. As an in-kind partner the Forschungszentrum Juelich will among others, design and manufacture the four liquid hydrogen Moderators, which are located above and below the Target. Those vessels are confining the cold hydrogen used to reduce the energy level of the fast neutrons, produced by spallation in the Target, in order to make the neutrons usable for neutron scattering instruments. Due to the requirements [1], a fluid dynamic analysis with pressure and temperature depended hydrogen data, taking into account the pseudo critical phenomena and the pulsed neutronic heating (pressure waves) is necessary. With the fluid dynamic results, a structure mechanical analysis including radiation damage investigation (RCC-MRx code [5]), low temperature properties as well as strength reduction by welding can be realized. Finally, the manufacturing and welding completes the design process.

  9. Comparative proteomics analysis of the root apoplasts of rice seedlings in response to hydrogen peroxide.

    Directory of Open Access Journals (Sweden)

    Lu Zhou

    Full Text Available BACKGROUND: Plant apoplast is the prime site for signal perception and defense response, and of great importance in responding to environmental stresses. Hydrogen peroxide (H(2O(2 plays a pivotal role in determining the responsiveness of cells to stress. However, how the apoplast proteome changes under oxidative condition is largely unknown. In this study, we initiated a comparative proteomic analysis to explore H(2O(2-responsive proteins in the apoplast of rice seedling roots. METHODOLOGY/PRINCIPAL FINDINGS: 14-day-old rice seedlings were treated with low concentrations (300 and 600 µM of H(2O(2 for 6 h and the levels of relative electrolyte leakage, malondialdehyde and H(2O(2 were assayed in roots. The modified vacuum infiltration method was used to extract apoplast proteins of rice seedling roots, and then two-dimensional electrophoresis gel analysis revealed 58 differentially expressed protein spots under low H(2O(2 conditions. Of these, 54 were successfully identified by PMF or MS/MS as matches to 35 different proteins including known and novel H(2O(2-responsive proteins. Almost all of these identities (98% were indeed apoplast proteins confirmed either by previous experiments or through publicly available prediction programs. These proteins identified are involved in a variety of processes, including redox homeostasis, cell wall modification, signal transduction, cell defense and carbohydrate metabolism, indicating a complex regulative network in the apoplast of seedling roots under H(2O(2 stress. CONCLUSIONS/SIGNIFICANCE: The present study is the first apoplast proteome investigation of plant seedlings in response to H(2O(2 and may be of paramount importance for the understanding of the plant network to environmental stresses. Based on the abundant changes in these proteins, together with their putative functions, we proposed a possible protein network that provides new insights into oxidative stress response in the rice root apoplast

  10. Microbial community analysis in a long-term membrane-less microbial electrolysis cell with hydrogen and methane production.

    Science.gov (United States)

    Rago, Laura; Ruiz, Yolanda; Baeza, Juan A; Guisasola, Albert; Cortés, Pilar

    2015-12-01

    A single-chamber microbial electrolysis cell (MEC) aiming at hydrogen production with acetate as sole carbon source failed due to methanogenesis build-up despite the significant amount of 2-bromoethanesulfonate (BES) dosage, 50 mM. Specific batch experiments and a thorough microbial community analysis, pyrosequencing and qPCR, of cathode, anode and medium were performed to understand these observations. The experimental data rebuts different hypothesis and shows that methanogenesis at high BES concentration was likely due to the capacity of some Archaea (hydrogen-oxidizing genus Methanobrevibacter) to resist high BES concentration up to 200 mM. Methanobrevibacter, of the Methanobacteriales order, represented almost the 98% of the total Archaea in the cathode whereas Geobacter was highly abundant in the anode (72% of bacteria). Moreover, at higher BES concentration (up to 200 mM), methanogenesis activity decreased resulting in an increase of homoacetogenic activity, which challenged the performance of the MEC for H2 production.

  11. Dynamic Project Risk Analysis and Management Based on Influence Diagrams

    Science.gov (United States)

    Liu, Xiaohua; Yue, Chaoyuan

    This paper presents a real-time process-oriented project risk analysis and management model which can be combined with the project general management, based on the hierarchical risk influence diagram which is constructed on the basis of network planning. Through network planning, it can solve the problems of the dynamic and overall identification of risk elements, and the showing and analysis of risk transfer along with the working procedure, and the timely and dynamic risk prevention and control as well. The influence diagram can effectively represent the risk combination and transfer in time and logic order. And it is good at the analysis of the sensitivity and control value of risk elements, as well as being convenient for communicating between experts, managers and owner. So the hierarchical risk influence diagram can make the decision of risk management timelier and more accurate. The problems of risk description, diagrams construction and risk evaluation are solved very well in applying the general influence diagram to dynamic project risk analysis. In the end, good result is attained in the example.

  12. RISK ANALYSIS APPLIED IN OIL EXPLORATION AND PRODUCTION

    African Journals Online (AJOL)

    ES Obe

    projects. Although the use of risk management techniques does not reduce the uncertainty in Oil field projects; it reduces the impact of the losses should an unfavourable event occur. Keywords: risk analysis, oil field, risk management, projects, investment opportunity. 1. Introduction. The Oil Exploration and Production is a.

  13. Risk analysis methods of the water resources system under uncertainty

    Directory of Open Access Journals (Sweden)

    Zeying GUI,Chenglong ZHANG,Mo Li,Ping GUO

    2015-09-01

    Full Text Available The main characteristic of the water resources system (WRS is its great complexity and uncertainty, which makes it highly desirable to carry out a risk analysis of the WRS. The natural environmental, social economic conditions as well as limitations of human cognitive ability are possible sources of the uncertainties that need to be taken into account in the risk analysis process. In this paper the inherent stochastic uncertainty and cognitive subjective uncertainty of the WRS are discussed first, from both objective and subjective perspectives. Then the quantitative characterization methods of risk analysis are introduced, including three criteria (reliability, resiliency and vulnerability and five basic optimization models (the expected risk value model, conditional value at risk model, chance-constrained risk model, minimizing probability of risk events model, and the multi-objective optimization model. Finally, this paper focuses on the various methods of risk analysis under uncertainty, which are summarized as random, fuzzy and mixed methods. A more comprehensive risk analysis methodology for the WRS is proposed based on the comparison of the advantages, disadvantages and applicable conditions of these three methods. This paper provides a decision support of risk analysis for researchers, policy makers and stakeholders of the WRS.

  14. Risk analysis of heat recovery steam generator with semi quantitative risk based inspection API 581

    Science.gov (United States)

    Prayogo, Galang Sandy; Haryadi, Gunawan Dwi; Ismail, Rifky; Kim, Seon Jin

    2016-04-01

    Corrosion is a major problem that most often occurs in the power plant. Heat recovery steam generator (HRSG) is an equipment that has a high risk to the power plant. The impact of corrosion damage causing HRSG power plant stops operating. Furthermore, it could be threaten the safety of employees. The Risk Based Inspection (RBI) guidelines by the American Petroleum Institute (API) 58 has been used to risk analysis in the HRSG 1. By using this methodology, the risk that caused by unexpected failure as a function of the probability and consequence of failure can be estimated. This paper presented a case study relating to the risk analysis in the HRSG, starting with a summary of the basic principles and procedures of risk assessment and applying corrosion RBI for process industries. The risk level of each HRSG equipment were analyzed: HP superheater has a medium high risk (4C), HP evaporator has a medium-high risk (4C), and the HP economizer has a medium risk (3C). The results of the risk assessment using semi-quantitative method of standard API 581 based on the existing equipment at medium risk. In the fact, there is no critical problem in the equipment components. Damage mechanisms were prominent throughout the equipment is thinning mechanism. The evaluation of the risk approach was done with the aim of reducing risk by optimizing the risk assessment activities.

  15. Mechanistic Study of Nitric Oxide Reduction by Hydrogen on Pt(100) (I): A DFT Analysis of the Reaction Network.

    Science.gov (United States)

    Bai, Yunhai; Mavrikakis, Manos

    2017-05-08

    Periodic, self-consistent density functional theory (DFT-GGA, PW91) calculations are used to study the reaction mechanism for nitric oxide (NO) reduction by hydrogen (H2) on Pt(100). Energetics of various N-O activation paths, including both direct and hydrogen-assisted N-O bond-breaking paths, and the formation of three different N-containing products (N2, N2O, and NH3), are systematically studied. On the basis of our analysis, NO* dissociation has a lower barrier than NO* hydrogenation to HNO* or NOH*, and therefore, the direct NO dissociation path is predicted to dominate N-O activation on clean Pt(100). The reaction of atomic N* with N* and NO* is proposed as the mechanism for N2 and N2O formation, respectively. NH3 formation from N* via three successive hydrogenation steps is also studied and is found to be kinetically more difficult than N2 and N2O formation from N*. Finally, NO adsorption phase diagrams on Pt(100) are constructed, and these phase diagrams suggest that, at low temperatures (e.g., 400 K), the Pt(100) surface may be covered by half a monolayer of NO. We propose that high NO coverage might affect the NO + H2 reaction mechanism, and therefore, one should explicitly take the NO coverage into consideration in first-principles studies to determine the reaction mechanism on catalyst surfaces under reaction conditions. A detailed analysis of high NO coverage effects on the reaction mechanism will be presented in a separate contribution.

  16. Risk analysis of analytical validations by probabilistic modification of FMEA

    DEFF Research Database (Denmark)

    Barends, D.M.; Oldenhof, M.T.; Vredenbregt, M.J.

    2012-01-01

    Risk analysis is a valuable addition to validation of an analytical chemistry process, enabling not only detecting technical risks, but also risks related to human failures. Failure Mode and Effect Analysis (FMEA) can be applied, using a categorical risk scoring of the occurrence, detection...... and severity of failure modes, and calculating the Risk Priority Number (RPN) to select failure modes for correction. We propose a probabilistic modification of FMEA, replacing the categorical scoring of occurrence and detection by their estimated relative frequency and maintaining the categorical scoring...

  17. Assessment and uncertainty analysis of groundwater risk.

    Science.gov (United States)

    Li, Fawen; Zhu, Jingzhao; Deng, Xiyuan; Zhao, Yong; Li, Shaofei

    2018-01-01

    Groundwater with relatively stable quantity and quality is commonly used by human being. However, as the over-mining of groundwater, problems such as groundwater funnel, land subsidence and salt water intrusion have emerged. In order to avoid further deterioration of hydrogeological problems in over-mining regions, it is necessary to conduct the assessment of groundwater risk. In this paper, risks of shallow and deep groundwater in the water intake area of the South-to-North Water Transfer Project in Tianjin, China, were evaluated. Firstly, two sets of four-level evaluation index system were constructed based on the different characteristics of shallow and deep groundwater. Secondly, based on the normalized factor values and the synthetic weights, the risk values of shallow and deep groundwater were calculated. Lastly, the uncertainty of groundwater risk assessment was analyzed by indicator kriging method. The results meet the decision maker's demand for risk information, and overcome previous risk assessment results expressed in the form of deterministic point estimations, which ignore the uncertainty of risk assessment. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Is the hydrogen production from biomass technology really sustainable? Answer by Life Cycle Emergy Analysis

    DEFF Research Database (Denmark)

    Liang, Hanwei; Ren, Jingzheng; Dong, Liang

    2016-01-01

    .8303 and the emergy index of sustainability (ESI) which is a measure of the sustainability of a product, a process or a service is 0.1996. Therefore, it is not sustainable in the long term perspective for hydrogen production from corn stalks by supercritical water gasification in the current situation of Huaibei city...... and utilization efficiency of corn stalks....

  19. Expert Opinion Analysis on Renewable Hydrogen Storage Systems Potential in Europe

    NARCIS (Netherlands)

    Astiaso Garcia, D.; Barbanera, F.; Cumo, F.; De Matteo, U.; Nastasi, B.

    2016-01-01

    Among the several typologies of storage technologies, mainly on different physical principles (mechanical, electrical and chemical), hydrogen produced by power to gas (P2G) from renewable energy sources complies with chemical storage principle and is based on the conversion of electrical energy into

  20. Analysis of Cost-Effective Off-Board Hydrogen Storage and Refueling Stations

    Energy Technology Data Exchange (ETDEWEB)

    Ted Barnes; William Liss

    2008-11-14

    This report highlights design and component selection considerations for compressed gas hydrogen fueling stations operating at 5000 psig or 350 bar. The primary focus is on options for compression and storage – in terms of practical equipment options as well as various system configurations and how they influence delivery performance and station economics.

  1. Developing an amperometric hydrogen peroxide sensor for an exhaled breath analysis system

    NARCIS (Netherlands)

    Wiedemair, Justyna; van Dorp, Henriëtte; Olthuis, Wouter; van den Berg, Albert

    In this work, we present a chip-integrated amperometric sensor targeted at the detection of hydrogen peroxide (H2O2) in the gaseous phase. Electrode chips are manufactured in a series of microfabrication steps and characterized electrochemically. Using such devices detection of H2O2 in an aqueous

  2. Analysis of atomic force microscopy phase data to dynamically detect adsorbed hydrogen under ambient conditions.

    Science.gov (United States)

    Young, Matthew J; Pfromm, Peter H; Rezac, Mary E; Law, Bruce M

    2014-10-14

    Characterization of the interactions of hydrogen with catalytic metal surfaces and the mass transfer processes involved in heterogeneous catalysis are important for catalyst development. Although a range of technologies for studying catalytic surfaces exist, much of it relies on high-vacuum conditions that preclude in situ research. In contrast, atomic force microscopy (AFM) provides an opportunity for direct observation of surfaces under or near actual reaction conditions. Tapping-mode AFM was explored here because it expands AFM beyond the usual topographic information toward speciation and other more subtle surface information. This work describes using phase-angle information from tapping-mode AFM to follow the interactions of hydrogen with palladium, polycarbonate, and iron. Real-time AFM phase-angle information allowed for the observation of multiphase mass transfer to and from the surface of palladium at atmospheric pressure and room temperature without the need for complex sample preparation. The AFM observations are quantitatively benchmarked against and confirm mass transfer predictions based on bulk hydrogen diffusion data. Additionally, they support recent studies that demonstrate the existence of multiple hydrogen states during interactions with palladium surfaces.

  3. Numerical analysis of accidental hydrogen releases from high pressure storage at low temperatures

    DEFF Research Database (Denmark)

    Markert, Frank; Melideo, Daniele; Baraldi, Daniele

    2014-01-01

    ) and temperatures (down to 20 K), e.g. cryogenic compressed gas storage covers pressures up to 35 MPa and temperatures between 33 K and 338 K. Accurate calculations of high pressure releases require real gas EOS. This paper compares a number of EOS to predict hydrogen properties typical in different storage types...

  4. Analysis of total hydrogen content in palm oil and palm kernel oil ...

    African Journals Online (AJOL)

    A fast and non-destructive technique based on thermal neutron moderation has been used for determining the total hydrogen content in two types of red palm oil (dzomi and amidze) and palm kernel oil produced by traditio-nal methods in Ghana. An equipment consisting of an 241Am-Be neutron source and 3He neutron ...

  5. Science Based Governance? EU Food Regulation Submitted to Risk Analysis

    NARCIS (Netherlands)

    Szajkowska, A.; Meulen, van der B.M.J.

    2014-01-01

    Anna Szajkowska and Bernd van der Meulen analyse in their contribution, Science Based Governance? EU Food Regulation Submitted to Risk Analysis, the scope of application of risk analysis and the precautionary principle in EU food safety regulation. To what extent does this technocratic,

  6. Operational Risk Management A Practical Approach to Intelligent Data Analysis

    CERN Document Server

    Kenett, Ron

    2010-01-01

    The book will introduce modern Operational Risk (OpR) Management and illustrates the various sources of OpR assessment and OpR mitigation. This book discusses how various data sources can be integrated and analyzed and how OpR is synergetic to other risk management activities such as Financial Risk Management and Internationalization. The topics will include state of the art technology such as semantic analysis, ontology engineering, data mining and statistical analysis.

  7. Common Methods for Security Risk Analysis

    National Research Council Canada - National Science Library

    Malboeuf, Sylvie; Sandberg-Maitland, William; Dziadyk, William; Bacic, Eugen

    2005-01-01

    .... The study provides a history of Canada's initiatives with respect to risk management and investigates how Canada can augment the Working Group with its experiences and its future initiatives and opportunities...

  8. Track inspection planning and risk measurement analysis.

    Science.gov (United States)

    2014-11-01

    This project models track inspection operations on a railroad network and discusses how the inspection results can : be used to measure the risk of failure on the tracks. In particular, the inspection times of the tracks, inspection frequency of the ...

  9. The Network's Data Security Risk Analysis

    Directory of Open Access Journals (Sweden)

    Emil BURTESCU

    2008-01-01

    Full Text Available Establishing the networks security risk can be a very difficult operation especially for the small companies which, from financial reasons can't appeal at specialist in this domain, or for the medium or large companies that don't have experience. The following method proposes not to use complex financial calculus to determine the loss level and the value of impact making the determination of risk level a lot easier.

  10. The Operational Risk – Comparative Analysis

    Directory of Open Access Journals (Sweden)

    Gabriela Victoria Anghelache

    2009-11-01

    Full Text Available In many cases operational risks tend to be underestimated, considering that the losses they cause are generally minor can’t threatening the survival of a bank. Losses resulting from these events come from a complex interaction between organizational factors, personal and market that do not fit into a simple classification scheme. Observing what happened in the past we can say that operational risk is an important question of the financial losses in the banking sector.

  11. Risk analysis for privacy and identity management

    OpenAIRE

    Wangen, Gaute Bjørklund

    2012-01-01

    ENGELSK: The concept of privacy was recognized as early as the time of Aristotle, and has been a theme of debate since. Risks to privacy are problematic because the concept of "privacy" holds different meaning and importance to different people and cultures. What is considered private in Europe, may not be considered private in China, and vice versa. This makes defining and detecting risks to privacy a complex matter. As people become increasingly dependent on online services, ...

  12. Experimental study of combustion behavior during continuous hydrogen injection with an operating igniter

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Zhe, E-mail: zhe.liang@cnl.ca; Clouthier, Tony; Thomas, Bryan

    2016-03-15

    Highlights: • Combustion during continuous hydrogen release. • Periodical slow burning with a low release rate or weak turbulence. • Fast global burning with stratified hydrogen or strong turbulence. • Initiation of standing flame. - Abstract: Deliberate hydrogen ignition systems have been widely installed in many water cooled nuclear power plants to mitigate hydrogen risk in a loss-of-coolant accident. Experimental studies were performed at a large scale facility to simulate a post-accident containment scenario, where hydrogen is released into a volume (not closed) with an energized igniter. The test chamber had a volume of 60 m{sup 3}. The test parameters included hydrogen injection mass flow rate, injection elevation, igniter elevation, and level of turbulence in the chamber. Several dynamic combustion behaviors were observed. Under certain conditions, slow burning occurred periodically or locally without significant pressurization, and the hydrogen concentration could be maintained near the lean hydrogen flammability limit or a steady hydrogen distribution profile could be formed with a maximum hydrogen concentration less than 9 vol.%. Under other conditions, a global fast burn or a burn moving along the hydrogen dispersion pathway was observed and was followed by an immediate initiation of a standing flame. The study provided a better understanding of the dynamic combustion behavior induced by a deliberate igniter during a continuous hydrogen release. The data can be used for validation of combustion models used for hydrogen safety analysis.

  13. Analysis of energy consumption and CO{sub 2} emissions of the life cycle of bio-hydrogen applied to the Portuguese road transportation sector

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Ana Filipa; Baptista, Patricia; Silva, Carla [IDMEC (Portugal). Dept. of Mechanical Engineering

    2010-07-01

    In this work the main objective is to analyze energy consumption and CO{sub 2} emissions of biohydrogen for use in the transportation sector in Portugal. A life cycle assessment will be performed in order to evaluate bio-hydrogen pathways, having biodiesel and conventional fossil diesel as reference. The pathways were production of feedstock, pre-treatment, treatment, compression, distribution and applications. For the well-to-tank analysis the SimaPro 7.1 software and excel tools are used. This study includes not only a well-to-tank analysis but also a tank-to-wheel analysis (using ADVISOR software) estimating hydrogen consumption and electricity consumption of a fuel cell hybrid and a plug-in hybrid. Several bio-hydrogen feedstocks to produce hydrogen through fermentation processes will be considered: potato peels. (orig.)

  14. Integrating Household Risk Mitigation Behavior in Flood Risk Analysis: An Agent-Based Model Approach.

    Science.gov (United States)

    Haer, Toon; Botzen, W J Wouter; de Moel, Hans; Aerts, Jeroen C J H

    2017-10-01

    Recent studies showed that climate change and socioeconomic trends are expected to increase flood risks in many regions. However, in these studies, human behavior is commonly assumed to be constant, which neglects interaction and feedback loops between human and environmental systems. This neglect of human adaptation leads to a misrepresentation of flood risk. This article presents an agent-based model that incorporates human decision making in flood risk analysis. In particular, household investments in loss-reducing measures are examined under three economic decision models: (1) expected utility theory, which is the traditional economic model of rational agents; (2) prospect theory, which takes account of bounded rationality; and (3) a prospect theory model, which accounts for changing risk perceptions and social interactions through a process of Bayesian updating. We show that neglecting human behavior in flood risk assessment studies can result in a considerable misestimation of future flood risk, which is in our case study an overestimation of a factor two. Furthermore, we show how behavior models can support flood risk analysis under different behavioral assumptions, illustrating the need to include the dynamic adaptive human behavior of, for instance, households, insurers, and governments. The method presented here provides a solid basis for exploring human behavior and the resulting flood risk with respect to low-probability/high-impact risks. © 2016 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.

  15. Vibrational analysis on the revised potential energy curve of the low-barrier hydrogen bond in photoactive yellow protein.

    Science.gov (United States)

    Kanematsu, Yusuke; Kamikubo, Hironari; Kataoka, Mikio; Tachikawa, Masanori

    2016-01-01

    Photoactive yellow protein (PYP) has a characteristic hydrogen bond (H bond) between p-coumaric acid chromophore and Glu46, whose OH bond length has been observed to be 1.21 Å by the neutron diffraction technique [Proc. Natl. Acad. Sci. 106, 440-4]. Although it has been expected that such a drastic elongation of the OH bond could be caused by the quantum effect of the hydrogen nucleus, previous theoretical computations including the nuclear quantum effect have so far underestimated the bond length by more than 0.07 Å. To elucidate the origin of the difference, we performed a vibrational analysis of the H bond on potential energy curve with O…O distance of 2.47 Å on the equilibrium structure, and that with O…O distance of 2.56 Å on the experimental crystal structure. While the vibrationally averaged OH bond length for equilibrium structure was underestimated, the corresponding value for crystal structure was in reasonable agreement with the corresponding experimental values. The elongation of the O…O distance by the quantum mechanical or thermal fluctuation would be indispensable for the formation of a low-barrier hydrogen bond in PYP.

  16. Vibrational analysis on the revised potential energy curve of the low-barrier hydrogen bond in photoactive yellow protein

    Directory of Open Access Journals (Sweden)

    Yusuke Kanematsu

    2016-01-01

    Full Text Available Photoactive yellow protein (PYP has a characteristic hydrogen bond (H bond between p-coumaric acid chromophore and Glu46, whose OH bond length has been observed to be 1.21 Å by the neutron diffraction technique [Proc. Natl. Acad. Sci. 106, 440–4]. Although it has been expected that such a drastic elongation of the OH bond could be caused by the quantum effect of the hydrogen nucleus, previous theoretical computations including the nuclear quantum effect have so far underestimated the bond length by more than 0.07 Å. To elucidate the origin of the difference, we performed a vibrational analysis of the H bond on potential energy curve with O…O distance of 2.47 Å on the equilibrium structure, and that with O…O distance of 2.56 Å on the experimental crystal structure. While the vibrationally averaged OH bond length for equilibrium structure was underestimated, the corresponding value for crystal structure was in reasonable agreement with the corresponding experimental values. The elongation of the O…O distance by the quantum mechanical or thermal fluctuation would be indispensable for the formation of a low-barrier hydrogen bond in PYP.

  17. Analysis of hydrogen, carbon, sulfur and volatile compounds in (U{sub 3}Si{sub 2} - Al) nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Sergio C.; Redigolo, Marcelo M.; Amaral, Priscila O.; Leao, Claudio; Oliveira, Glaucia A.C. de; Bustillos, Oscar V., E-mail: ovega@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Uranium silicide U{sub 3}Si{sub 2} is used as nuclear fuel in the research nuclear reactor IEA-R1 at IPEN/CNEN, Sao Paulo, Brazil. The U{sub 3}Si{sub 2} is dispersed in aluminum reaching high densities of uranium in the nucleus of the fuel, up to 4.8 gU cm{sup -3}. This nuclear fuel must comply with a quality control, which includes analysis of hydrogen, carbon and sulfur for the U{sub 3}Si{sub 2} and volatile compound for the aluminum. Hydrogen, carbon and sulfur are analyzed by the method of Radio Frequency gas extraction combustion coupled with Infrared detector. Volatile compounds are analyzed by the method of heated gas extraction coupled with gravimetric measurement. These methods are recommended by the American Society for Testing Materials (ASTM) for nuclear materials. The average carbon and sulfur measurements are 30 μg g{sup -1} and 3 μg g{sup -1}, respectively, and 40 μg g{sup -1} for volatile compounds. The hydrogen analyzer is a TCHEN 600 LECO, carbon and sulfur analyzer is a CS 244 LECO and the volatile compounds analyzer is a home-made apparatus that use a resistant furnace, a gas pipe measurement and a glove-box with controlled atmosphere where an analytical balance has been installed, this analyzer was made at IPEN laboratory. (author)

  18. DGGE analysis of buffalo manure eubacteria for hydrogen production: effect of pH, temperature and pretreatments.

    Science.gov (United States)

    Carillo, Petronia; Carotenuto, Claudia; Di Cristofaro, Filomena; Kafantaris, Ioannis; Lubritto, Carmine; Minale, Mario; Morrone, Biagio; Papa, Stefania; Woodrow, Pasqualina

    2012-12-01

    Buffalo dung is a low-cost substrate with plenty of carbohydrates, an optimal carbon/nitrogen ratio, and a rich microbial flora, and could become a valuable source of biogas. Therefore, in the present study we compared the type and amount of specific eubacteria to the different configurations of pH, temperature and thermal pretreatment after fermentation in batch reactors in order to understand the suitability of buffalo manure for hydrogen production. The phylogenetic structure of the microbial community in fermentation samples was studied using denaturing gradient gel electrophoresis to generate fingerprints of 16S rRNA genes. The sequences analysis revealed abundance of the phyla Bacteroidetes and Firmicutes, and in particular of the order Clostridiales. Very active hydrogen producing bacteria belonging to Clostridium cellulosi species were identified demonstrating the suitability of this substrate to produce hydrogen. Moreover, a large fraction of 16S-rDNA amplicons could not be assigned to lower taxonomic ranks, demonstrating that numerous microorganisms involved in anaerobic fermentation in digesters or bioreactors are still unclassified or unknown.

  19. Transcriptional analysis of Mycobacterium fortuitum cultures upon hydrogen peroxide treatment using the novel standard rrnA-P1

    Directory of Open Access Journals (Sweden)

    Rebollo María

    2008-06-01

    Full Text Available Abstract Background The ability of an intracellular pathogen to establish infection depends on the capacity of the organism to survive and replicate inside the host. Mycobacterium fortuitum is a bacteria that contains genes involved in the detoxification of the oxygen reactive species such as those produced by the host during the infection. In this work, we investigate the effects of hydrogen peroxide on the transcription and expression of these genes by developing a real time quantitative PCR technique (qRT-PCR using the ribosomal promoter region (rrnA-P1 as reference product for quantification of the mRNA levels. Results M. fortuitum cultures were treated with different hydrogen peroxide concentrations (0.02 to 20 mM during several periods of time (30 to 120 minutes. The activity of the enzymes KatGII and SodA, and the transcription of corresponding genes were evaluated. The transcriptional regulator furAII gene was also studied. The ribosomal promoter region rrnA-P1 was validated as referential product under the stress conditions checked by qRT-PCR. Minor changes were observed under the conditions tested except when bacteria were incubated in the presence of 20 mM hydrogen peroxide. Under those conditions, the levels of transcription of the three genes under study increased at 30 minutes of treatment. The viability of the bacteria was not influenced under the conditions tested. Conclusion In this work, we have quantified transcriptional responses to stress suggesting that, the opportunistic pathogen M. fortuitum is more resistant and differs in behaviour in the presence of hydrogen peroxide, when compared to the major pathogen Mycobacterium tuberculosis and the saprophyte Mycobacterium smegmatis. Besides, we demonstrate the mycobacterial non-coding region rrnA-P1 to be a suitable reference product in the analysis of qRT-PCR transcriptional data of M. fortuitum.

  20. Financial Risk Factor Analysis for Facility Gas Leakages of H2 and NG

    Directory of Open Access Journals (Sweden)

    In-Bok Lee

    2016-09-01

    Full Text Available Fuel cells may be the key to a more environmentally-friendly future because they emit low carbon dioxide per unit of energy supplied. However, little work has investigated the potential financial risks pertaining to fuel cell systems. Often used in the analysis of the safety of systems involving flammable or hazardous materials, risk factor analysis has recently been used to analyze the potential financial losses that may occur from industrial hazards. Therefore, this work undertakes a financial risk factor analysis to determine the costs of leakages of hydrogen and natural gas, which are used in fuel cell systems. Total leakage was calculated from an analysis of several leakage rates and modes. The impact of applying appropriate detection and prevention systems was also investigated. The findings were then used to analyze the consequences for various sections of the system and to calculate the overall cost based on facility outage or damage, and the cost of taking safety precautions. This provides a basis for comparison among proposed potential reactionary measures.

  1. Application of Explosion Area Control Volume in MELCOR Code for Safety Analysis of Hydrogen and Dust Explosion Accident in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Soo Min; Moon, Sung Bo; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of)

    2016-10-15

    Nuclear fusion power is said to be one of the most promising energy sources to generate large amount of energy with less radioactive waste or less radiological hazard due to nuclear accidents. However, the nuclear fusion device still confronts the tritium management tasks because they hold considerable amount of tritium for fusion reaction. In so-called 'Hypothetical events,' the beyond the design basis accidents in nuclear fusion reactors, a radiological material release may occur. Therefore, safety analysis for hydrogen mitigation and management should be performed to demonstrate the ultimate safety margin of the design to evade from situations such as the Fukushima accident. For ITER facility, accident analysis report (AAR) demonstrates the analysis of selected postulated accident scenarios holding the most challenging in terms of expected radiological consequences including beyond design basis accidents. Hydrogen and dust explosion in the ITER vacuum vessel using explosion area was modeled with MELCOR code. The vacuum vessel confinement was ruptured making a penetration line between vacuum vessel and port/NBI cell. The overall pressure transient of the accident was similar with the ITER accident analysis report (AAR) results, however, amount of tungsten dust release into the environment was significantly different.

  2. Electrochemical Hydrogen Compressor

    Energy Technology Data Exchange (ETDEWEB)

    Lipp, Ludwig [FuelCell Energy, Inc., Torrington, CT (United States)

    2016-01-21

    Conventional compressors have not been able to meet DOE targets for hydrogen refueling stations. They suffer from high capital cost, poor reliability and pose a risk of fuel contamination from lubricant oils. This project has significantly advanced the development of solid state hydrogen compressor technology for multiple applications. The project has achieved all of its major objectives. It has demonstrated capability of Electrochemical Hydrogen Compression (EHC) technology to potentially meet the DOE targets for small compressors for refueling sites. It has quantified EHC cell performance and durability, including single stage hydrogen compression from near-atmospheric pressure to 12,800 psi and operation of EHC for more than 22,000 hours. Capital cost of EHC was reduced by 60%, enabling a path to meeting the DOE cost targets for hydrogen compression, storage and delivery ($2.00-2.15/gge by 2020).

  3. Risk Analysis for the Different Consolidation Proposals

    CERN Document Server

    Strait, J

    2009-01-01

    In parallel with the repairs in sector 34, improvements are planned to a number of systems, to allow safe detection of faults similar to the one which caused the incident of 19 September, and to limit the damage should a similar incident nonetheless occur. These include improved bus and quench detection systems, improved pressure relief for the insulating and beam vacuum systems, and improved anchoring of the SSS to the tunnel floor. Not all of the planned mitigations, however, may be fully implemented before the restart of the LHC in 2009. I will review the potential benefits of partial or complete implementation of each of the planned improvements, individually or together with others, and conversely the potential risks (consequences) of delayed implementation. I will also review the risks that remain even after the planned consolidation is complete. Considering all proposals and the different risks, I will comment on what would be the best strategy for consolidation, and on the strategy for operations unde...

  4. The Total Risk Analysis of Large Dams under Flood Hazards

    Directory of Open Access Journals (Sweden)

    Yu Chen

    2018-02-01

    Full Text Available Dams and reservoirs are useful systems in water conservancy projects; however, they also pose a high-risk potential for large downstream areas. Flood, as the driving force of dam overtopping, is the main cause of dam failure. Dam floods and their risks are of interest to researchers and managers. In hydraulic engineering, there is a growing tendency to evaluate dam flood risk based on statistical and probabilistic methods that are unsuitable for the situations with rare historical data or low flood probability, so a more reasonable dam flood risk analysis method with fewer application restrictions is needed. Therefore, different from previous studies, this study develops a flood risk analysis method for large dams based on the concept of total risk factor (TRF used initially in dam seismic risk analysis. The proposed method is not affected by the adequacy of historical data or the low probability of flood and is capable of analyzing the dam structure influence, the flood vulnerability of the dam site, and downstream risk as well as estimating the TRF of each dam and assigning corresponding risk classes to each dam. Application to large dams in the Dadu River Basin, Southwestern China, demonstrates that the proposed method provides quick risk estimation and comparison, which can help local management officials perform more detailed dam safety evaluations for useful risk management information.

  5. Analysis of Energy Storage System with Distributed Hydrogen Production and Gas Turbine

    Science.gov (United States)

    Kotowicz, Janusz; Bartela, Łukasz; Dubiel-Jurgaś, Klaudia

    2017-12-01

    Paper presents the concept of energy storage system based on power-to-gas-to-power (P2G2P) technology. The system consists of a gas turbine co-firing hydrogen, which is supplied from a distributed electrolysis installations, powered by the wind farms located a short distance from the potential construction site of the gas turbine. In the paper the location of this type of investment was selected. As part of the analyses, the area of wind farms covered by the storage system and the share of the electricity production which is subjected storage has been changed. The dependence of the changed quantities on the potential of the hydrogen production and the operating time of the gas turbine was analyzed. Additionally, preliminary economic analyses of the proposed energy storage system were carried out.

  6. The Hydrogen bonding effects in structural analysis of phenilon C-2: the quantum-chemical interpretation

    Directory of Open Access Journals (Sweden)

    Andrey V. Tokar

    2017-11-01

    Full Text Available Using ab initio methods of quantum chemistry the structure and spectral properties for molecular complexes, which were formed by monomer of phenilon С-2 chain, including some intra- and intermolecular hydrogen bonding effects as well as electrostatic interactions with evaluation of their contributions in total stabilization energy, have been investigated at natural bond orbitals theory. It is shown, that the overlapping of n1,2(O→ σ*(NН type with energies 15.4 and 9.5 kJ/mol, which correspond to the strong hydrogen bonding between amide groups, is a main direction for co-operating of some area for structural fragments of macromolecules. The proposed theoretical models are validated in reflection of spectral and energetic parameters for investigating system.

  7. Analysis of Energy Storage System with Distributed Hydrogen Production and Gas Turbine

    Directory of Open Access Journals (Sweden)

    Kotowicz Janusz

    2017-12-01

    Full Text Available Paper presents the concept of energy storage system based on power-to-gas-to-power (P2G2P technology. The system consists of a gas turbine co-firing hydrogen, which is supplied from a distributed electrolysis installations, powered by the wind farms located a short distance from the potential construction site of the gas turbine. In the paper the location of this type of investment was selected. As part of the analyses, the area of wind farms covered by the storage system and the share of the electricity production which is subjected storage has been changed. The dependence of the changed quantities on the potential of the hydrogen production and the operating time of the gas turbine was analyzed. Additionally, preliminary economic analyses of the proposed energy storage system were carried out.

  8. Comment on "Entropy and complexity analysis of hydrogenic Rydberg atoms" [J. Math. Phys. 54, 052109 (2013)

    Science.gov (United States)

    Jiao, Li Guang; Zan, Li Rong

    2017-10-01

    In a recent paper [S. López-Rosa et al., J. Math. Phys. 54, 052109 (2013)], the authors made detailed investigations on the information-theoretic quantities for hydrogenic atoms in Rydberg states. Asymptotic forms of different types of complexity measures (Crámer-Rao, Fisher-Shannon, and LMC types) in both position and momentum spaces were obtained for hydrogenic states (n,l,m) with fixed l and increasingly large n. However, the expressions for the Crámer-Rao complexity are incorrect due to the wrong definition of variance. The correct form of this complexity in position space is presented exactly in this work. In momentum space, two different definitions of variance are provided and corresponding Crámer-Rao complexities are discussed separately. In either case, the momentum complexity increases much faster than that in position space when increasing principal quantum number n.

  9. Comparative Analysis of Schemes to Form a Hydrogen-Air Mixture in the Radial Pylons Channel

    Directory of Open Access Journals (Sweden)

    D. P. Alekseev

    2015-01-01

    Full Text Available The study of the processes occurring in the scramjet is an important task. These processes include formation of a hydrogen-air mixture to the combustion chamber scramjet. The experimental study of such processes involves various difficulties. Therefore the use of mathematical models and numerical modeling to analyze such problems is of importance.In this paper we consider the formation of hydrogen-air mixture by injecting hydrogen into concurrent supersonic airflow by the radial pylons arranged in the three-dimensional channel with a central coaxial cylinder. As a basis of the geometric model, a channel of circular cross section is taken, which is a sector in axisymmetric formulation. In the channel pylons are set. The paper considers pylons of two different shapes, as well as two versions of their location in the channel. Pylons are different in height, fastening method, and different flow vortex generators (turbulator, designed to improve the mixing efficiency. The pylon №1 is attached to the channel wall and occupies no more than 1/3 of the channel radius in radial direction. The pylon №2 is located along the entire channel radius and fastened with its one side to the wall of the channel and with another one to the coaxial cylinder extending along the axis of symmetry. Pylons are distinguished by different flow turbulators designed to improve the mixing efficiency. Hydrogen injection is carried out from the pylon surface before a turbulator. Hydrogen injection angle relative to the axis of the channel in the case of the first turbulator arises from its geometry to be 12º, in the case of the second turbulator it is 0º (to reduce losses of the total flow pressure. We study the influence of the geometric shape of the pylons on characteristics of emerging hydrogen-air mixture flow.Research is conducted numerically on the basis of Reynolds equations for a turbulent motion of viscous multicomponent gas with k  turbulence model. The

  10. Integration of phase change materials in compressed hydrogen gas systems: Modelling and parametric analysis

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Rothuizen, Erasmus; Jørgensen, Jens-Erik

    2016-01-01

    A dynamic fueling model is built to simulate the fueling process of a hydrogen tank with an integrated passive cooling system. The study investigates the possibility of absorbing a part of the heat of compression in the high latent-heat material during melting, with the aim of saving the monetary...... and energy resources spent at the refueling station to cool the gas prior to tank filling. This is done while respecting the technical constraint of keeping the walls below the critical temperature of 85 C to ensure the mechanical stability of the storage system even when the gas is fueled at ambient...... temperature. Results show that a 10-mm-thick layer of paraffin wax can absorb enough heat to reduce the adiabatic temperature by 20 K when compared to a standard Type IV tank, but its influence on the hydrogen peak temperature that occurs at the end of refueling is modest. The heat transfer from the gas...

  11. Evaluation of the plasma hydrogen isotope content by residual gas analysis at JET and AUG

    Science.gov (United States)

    Drenik, A.; Alegre, D.; Brezinsek, S.; De Castro, A.; Kruezi, U.; Oberkofler, M.; Panjan, M.; Primc, G.; Reichbauer, T.; Resnik, M.; Rohde, V.; Seibt, M.; Schneider, P. A.; Wauters, T.; Zaplotnik, R.; ASDEX-Upgrade, the; EUROfusion MST1 Teams; contributors, JET

    2017-12-01

    The isotope content of the plasma reflects on the dynamics of isotope changeover experiments, efficiency of wall conditioning and the performance of a fusion device in the active phase of operation. The assessment of the isotope ratio of hydrogen and methane molecules is used as a novel method of assessing the plasma isotope ratios at JET and ASDEX-Upgrade (AUG). The isotope ratios of both molecules in general shows similar trends as the isotope ratio detected by other diagnostics. At JET, the absolute values of RGA signals are in relatively good agreement with each other and with spectroscopy data, while at AUG the deviation from neutral particle analyser data are larger, and the results show a consistent spatial distribution of the isotope ratio. It is further shown that the isotope ratio of the hydrogen molecule can be used to study the degree of dissociation of the injected gas during changeover experiments.

  12. Stress Analysis in Managing the Region’s Budget Risks

    Directory of Open Access Journals (Sweden)

    Natalya Pavlovna Pazdnikova

    2014-09-01

    Full Text Available The article addresses the implementation of budget risk management methods into the practices of governmental authorities. Drawing on the example of a particular region the article aims to demonstrate the possible methods of budget risk management. The authors refine the existing approaches to the notion of risk in its relation to budget system by introducing the notion of “budget risk.” Here the focus is the risk of default of budget spending in full which causes underfunding of territories and decrease in quality of life in the region. The authors have particularized the classification of budget risks and grouped together the criteria and factors which significantly influence the assessment and choice of method to manage budget risks. They hypothesize that budget risk is a financial risk. Therefore, the methods of financial risks management can be applied to budget risks management. The authors suggest a methodological approach to risk assessment based on correlation and regression analysis of program financing. The application of Kendall rank correlation coefficient allowed to assess the efficiency of budget spending on the implementation of state programs in Perm Krai. Two clusters — “Nature management and infrastructure” and “Public security” — turned out to be in the zone of high budget risk. The method of stress analysis, which consists in calculating Value at Risk (VaR, was applied to budget risks that in terms of probability are classified as critical. In order to assess risk as probability rate, the amount of Perm Krai deficit budget was calculated as induced variable from budget revenues and spending. The results demonstrate that contemporary management of public resources in the regions calls for the implementation of new management tools of higher quality and budget risk management is one of them.

  13. Integrated Hybrid System Architecture for Risk Analysis

    Science.gov (United States)

    Moynihan, Gary P.; Fonseca, Daniel J.; Ray, Paul S.

    2010-01-01

    A conceptual design has been announced of an expert-system computer program, and the development of a prototype of the program, intended for use as a project-management tool. The program integrates schedule and risk data for the purpose of determining the schedule applications of safety risks and, somewhat conversely, the effects of changes in schedules on changes on safety. It is noted that the design has been delivered to a NASA client and that it is planned to disclose the design in a conference presentation.

  14. Quantitative Risk Analysis for Homeland Security Resource Allocation

    Science.gov (United States)

    2006-12-01

    pork barrel” to protect the interests of their home states or districts. In light of this, the 9/11 Commission recommended that “homeland security...have touched other industries beyond finance. Molak breaks some of these down and offers six types of risk analysis: chemical risk analysis, cancer ...nuclear plant safety.179 The insurance industry also uses QRA to evaluate relationships between smokers and lung cancer .180 The same analysis can

  15. Permeability test and fuzzy orthogonal analysis of hydrogenated nitrile O-ring

    OpenAIRE

    Hu, Qin; Wan, Changcheng; Wang, Changxin

    2015-01-01

    In the high temperature, high pressure and high corrosive environment of the oil and gas drilling downhole, the weatherability of rubber sealing material has a great influence on the production safety. In order to study the important degree of every key environmental factor in downhole influencing the sealing performance of rubber sealing material, a new device of simulating downhole environment is designed to test the permeability of O-ring. The sample is hydrogenated nitrile O-ring and orth...

  16. CH spectroscopy for carbon chemical erosion analysis in high density low temperature hydrogen plasma

    NARCIS (Netherlands)

    Westerhout, J.; Cardozo, N. J. L.; Rapp, J.; van Rooij, G. J.

    2009-01-01

    The CH A-X molecular band is measured upon seeding the hydrogen plasma in the linear plasma generator Pilot-PSI [electron temperature T-e=0.1-2.5 eV and electron density n(e)=(0.5-5) X 10(20) m(-3)] with methane. Calculated inverse photon efficiencies for these conditions range from 3 up to

  17. Current research and development activities on fission products and hydrogen risk after the accident at Fukushima Daiichi Nuclear Power Station

    Directory of Open Access Journals (Sweden)

    Takeshi Nishimura

    2015-02-01

    Full Text Available After the Fukushima Daiichi nuclear power plant (NPP accident, new regulatory requirements were enforced in July 2013 and a backfit was required for all existing nuclear power plants. It is required to take measures to prevent severe accidents and mitigate their radiological consequences. The Regulatory Standard and Research Department, Secretariat of Nuclear Regulation Authority (S/NRA/R has been conducting numerical studies and experimental studies on relevant severe accident phenomena and countermeasures. This article highlights fission product (FP release and hydrogen risk as two major areas. Relevant activities in the S/NRA/R are briefly introduced, as follows: 1. For FP release: Identifying the source terms and leak mechanisms is a key issue from the viewpoint of understanding the progression of accident phenomena and planning effective countermeasures that take into account vulnerabilities of containment under severe accident conditions. To resolve these issues, the activities focus on wet well venting, pool scrubbing, iodine chemistry (in-vessel and ex-vessel, containment failure mode, and treatment of radioactive liquid effluent. 2. For hydrogen risk: because of three incidents of hydrogen explosion in reactor buildings, a comprehensive reinforcement of the hydrogen risk management has been a high priority topic. Therefore, the activities in evaluation methods focus on hydrogen generation, hydrogen distribution, and hydrogen combustion.

  18. Perchlorate reduction by hydrogen autotrophic bacteria and microbial community analysis using high-throughput sequencing.

    Science.gov (United States)

    Wan, Dongjin; Liu, Yongde; Niu, Zhenhua; Xiao, Shuhu; Li, Daorong

    2016-02-01

    Hydrogen autotrophic reduction of perchlorate have advantages of high removal efficiency and harmless to drinking water. But so far the reported information about the microbial community structure was comparatively limited, changes in the biodiversity and the dominant bacteria during acclimation process required detailed study. In this study, perchlorate-reducing hydrogen autotrophic bacteria were acclimated by hydrogen aeration from activated sludge. For the first time, high-throughput sequencing was applied to analyze changes in biodiversity and the dominant bacteria during acclimation process. The Michaelis-Menten model described the perchlorate reduction kinetics well. Model parameters q(max) and K(s) were 2.521-3.245 (mg ClO4(-)/gVSS h) and 5.44-8.23 (mg/l), respectively. Microbial perchlorate reduction occurred across at pH range 5.0-11.0; removal was highest at pH 9.0. The enriched mixed bacteria could use perchlorate, nitrate and sulfate as electron accepter, and the sequence of preference was: NO3(-) > ClO4(-) > SO4(2-). Compared to the feed culture, biodiversity decreased greatly during acclimation process, the microbial community structure gradually stabilized after 9 acclimation cycles. The Thauera genus related to Rhodocyclales was the dominated perchlorate reducing bacteria (PRB) in the mixed culture.

  19. Expert Opinion Analysis on Renewable Hydrogen Storage Systems Potential in Europe

    Directory of Open Access Journals (Sweden)

    Davide Astiaso Garcia

    2016-11-01

    Full Text Available Among the several typologies of storage technologies, mainly on different physical principles (mechanical, electrical and chemical, hydrogen produced by power to gas (P2G from renewable energy sources complies with chemical storage principle and is based on the conversion of electrical energy into chemical energy by means of the electrolysis of water which does not produce any toxic or climate-relevant emission. This paper aims to pinpoint the potential uses of renewable hydrogen storage systems in Europe, analysing current and potential locations, regulatory framework, governments’ outlooks, economic issues, and available renewable energy amounts. The expert opinion survey, already used in many research articles on different topics including energy, has been selected as an effective method to produce realistic results. The obtained results highlight strategies and actions to optimize the storage of hydrogen produced by renewables to face varying electricity demand and generation-driven fluctuations reducing the negative effects of the increasing share of renewables in the energy mix of European Countries.

  20. Hydrogen from biomass gas steam reforming for low temperature fuel cell: energy and exergy analysis

    Directory of Open Access Journals (Sweden)

    A. Sordi

    2009-03-01

    Full Text Available This work presents a method to analyze hydrogen production by biomass gasification, as well as electric power generation in small scale fuel cells. The proposed methodology is the thermodynamic modeling of a reaction system for the conversion of methane and carbon monoxide (steam reforming, as well as the energy balance of gaseous flow purification in PSA (Pressure Swing Adsorption is used with eight types of gasification gases in this study. The electric power is generated by electrochemical hydrogen conversion in fuel cell type PEMFC (Proton Exchange Membrane Fuel Cell. Energy and exergy analyses are applied to evaluate the performance of the system model. The simulation demonstrates that hydrogen production varies with the operation temperature of the reforming reactor and with the composition of the gas mixture. The maximum H2 mole fraction (0.6-0.64 mol.mol-1 and exergetic efficiency of 91- 92.5% for the reforming reactor are achieved when gas mixtures of higher quality such as: GGAS2, GGAS4 and GGAS5 are used. The use of those gas mixtures for electric power generation results in lower irreversibility and higher exergetic efficiency of 30-30.5%.

  1. Numerical analysis of hydrogen-assisted rolling-contact fatigue of wind turbine bearings

    Directory of Open Access Journals (Sweden)

    J. Toribio

    2014-10-01

    Full Text Available Offshore wind parks at locations further from the shore often involve serious difficulties, e.g. the maintenance. The bearings of offshore wind turbines are prone to suffer hydrogen-assisted rolling-contact fatigue (HA-RCF. Three important aspects linked with bearing failures are being extensively researched: (i rolling contact fatigue (RCF, (ii influence of carbide particles on fatigue life, and (iii local microplastic strain accumulation via ratcheting. However, there is no reference related to bearing failure in harsh environment. This way, this paper helps to gain a better understanding of the influence of hydrogen on the service life of offshore wind turbine bearings through a numerical study. So, the widely used RCF ball-on-rod test was simulated by finite element method in order to obtain the stress-strain state inside the bearings during life in service and, from this, to elucidate the potential places where the hydrogen could be more harmful and, therefore, where the bearing material should be improved.

  2. Risk Analysis and Security Countermeasure Selection

    CERN Document Server

    Norman, Thomas L

    2009-01-01

    Explains how to evaluate the appropriateness of security countermeasures, from a cost-effectiveness perspective. This title guides readers from basic principles to complex processes in a step-by-step fashion, evaluating DHS-approved risk assessment methods, including CARVER, API/NPRA, RAMCAP, and various Sandia methodologies

  3. Evaluation of the Impact That PARs Have on the Hydrogen Risk in the Reactor Containment: Methodology and Application to PSA Level 2

    Directory of Open Access Journals (Sweden)

    Ahmed Bentaib

    2010-01-01

    Full Text Available This paper presents a methodology and its application to a Level 2 Probabilistic Safety Assessment (PSA-2, to evaluate the impact of the Passive Autocatalytic Recombiners (PARs on the hydrogen risk in the reactor containment in case of a severe accident. Among the whole set of accidental scenarios calculated in the framework of the PSA-2, nine have been selected as representative in terms of the in-vessel hydrogen production rate and in-vessel total produced hydrogen mass. Five complementary scenarios have been added as representative of the core reflooding situations. For this set of selected scenarios the evolution of the conditions in the containment (i.e., pressure, temperature, and composition during the in-vessel phase of the accident has been evaluated by means of a lumped parameter approach. The use of spray systems in the containment has also been considered as well as the presence of recombiners. Moreover, the ignition by recombiners of the flammable atmosphere has been considered.

  4. Rapid analysis of urinary opiates using fast gas chromatography–mass spectrometry and hydrogen as a carrier gas

    Directory of Open Access Journals (Sweden)

    Sumandeep Rana

    2014-09-01

    Gas chromatographic–mass spectrometric analysis was performed in electron ionization mode by selective ion monitoring, using hydrogen as a carrier gas, a short narrow bore GC capillary column, and fast temperature program, allowing for a rapid analytical cycle to maximize the instrument time for high throughput laboratories. While maintaining specificity for these drugs, concentrations in human urine ranging from 50 to 5,000 ng/mL can be measured with intraday and interday imprecision, expressed as variation coefficients, of less than 2.3% for all analytes within a run time of less than 3.5 minutes.

  5. Preliminary risk analysis of an Hydrogen production plant using the reformed process of methane with vapor coupled to a high temperature nuclear reactor; Analisis preliminar de riesgo de una planta de produccion de hidrogeno utilizando el proceso de reformado de metano con vapor acoplada a un reactor nuclear de alta temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Flores y Flores, A. [Facultad de Ingenieria, UNAM, 04510 Mexico D.F. (Mexico)]. E-mail: alain_fyf@yahoo.com; Nelson E, P.F.; Francois L, J.L. [Facultad de Ingenieria, Laboratorio de Analisis en Ingenieria de Reactores Nucleares, UNAM, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Morelos (Mexico)

    2004-07-01

    It is necessary to identify the different types of dangers, as well as their causes, probabilities and consequences of the same ones, inside plants, industries and any process to classify the risks. This work is focused in particular to a study using the technical HAZOP (Hazard and Operability) for a plant of reformed of methane with vapor coupled to a nuclear reactor of the type HTTR (High Temperature Test Reactor), which is designed to be built in Japan. In particular in this study the interaction is analyzed between the nuclear reactor and the plant of reformed of methane with vapor. After knowing the possible causes of risk one it is built chart of results of HAZOP to have a better vision of the consequences of this faults toward the buildings and constructions, to people and the influence of the fault on each plant; for what there are proposed solutions to mitigate these consequences or to avoid them. The work is divided in three sections: a brief introduction about the technique of HAZOP; some important aspects of the plant of reformed of methane with vapor; and the construction of the chart of results of HAZOP. (Author)

  6. Hydrogen Generator

    Science.gov (United States)

    1983-01-01

    A unit for producing hydrogen on site is used by a New Jersey Electric Company. The hydrogen is used as a coolant for the station's large generator; on-site production eliminates the need for weekly hydrogen deliveries. High purity hydrogen is generated by water electrolysis. The electrolyte is solid plastic and the control system is electronic. The technology was originally developed for the Gemini spacecraft.

  7. Hydrogen energy systems studies

    Energy Technology Data Exchange (ETDEWEB)

    Ogden, J.M.; Steinbugler, M.; Dennis, E. [Princeton Univ., NJ (United States)] [and others

    1995-09-01

    For several years, researchers at Princeton University`s Center for Energy and Environmental Studies have carried out technical and economic assessments of hydrogen energy systems. Initially, we focussed on the long term potential of renewable hydrogen. More recently we have explored how a transition to renewable hydrogen might begin. The goal of our current work is to identify promising strategies leading from near term hydrogen markets and technologies toward eventual large scale use of renewable hydrogen as an energy carrier. Our approach has been to assess the entire hydrogen energy system from production through end-use considering technical performance, economics, infrastructure and environmental issues. This work is part of the systems analysis activity of the DOE Hydrogen Program. In this paper we first summarize the results of three tasks which were completed during the past year under NREL Contract No. XR-11265-2: in Task 1, we carried out assessments of near term options for supplying hydrogen transportation fuel from natural gas; in Task 2, we assessed the feasibility of using the existing natural gas system with hydrogen and hydrogen blends; and in Task 3, we carried out a study of PEM fuel cells for residential cogeneration applications, a market which might have less stringent cost requirements than transportation. We then give preliminary results for two other tasks which are ongoing under DOE Contract No. DE-FG04-94AL85803: In Task 1 we are assessing the technical options for low cost small scale production of hydrogen from natural gas, considering (a) steam reforming, (b) partial oxidation and (c) autothermal reforming, and in Task 2 we are assessing potential markets for hydrogen in Southern California.

  8. Network analysis and percolation transition in hydrogen bonded clusters: nitric acid and water extracted by tributyl phosphate.

    Science.gov (United States)

    Servis, Michael J; Wu, David T; Braley, Jenifer C

    2017-05-10

    Extraction of polar molecules by amphiphilic species results in a complex variety of clusters whose topologies and energetics control phase behavior and efficiency of liquid-liquid separations. A computational approach including quantum mechanical vibrational frequency calculations and molecular dynamics simulation with intermolecular network theory is used to provide a robust assessment of extractant and polar solute association through hydrogen bonding in the tributyl phosphate (TBP)/HNO3/H2O/dodecane system for the first time. The distribution of local topologies of the TBP/HNO3/H2O hydrogen bonded clusters is shown to be consistent with an equilibrium binding model. Mixed TBP/HNO3/H2O clusters are predicted that have not been previously observable in experiment due to limitations in scattering and spectroscopic resolution. Vibrational frequency calculations are compared with experimental data to validate the experimentally observed TBP-HNO3-HNO3 Chain structure. At high nitric acid and water loading, large hydrogen-bonded clusters of 20 to 80 polar solutes formed. The cluster sizes were found to be exponentially distributed, consistent with a constant average solute association free energy in that size range. Due to the deficit of hydrogen bond donors in the predominantly TBP/HNO3 organic phase, increased water concentrations lower the association free energy and enable growth of larger cluster sizes. For sufficiently high water concentrations, changes in the cluster size distribution are found to be consistent with the formation of a percolating cluster rather than reverse micelles, as has been commonly assumed for the occurrence of an extractant-rich third phase in metal-free solvent extraction systems. Moreover, the compositions of the large clusters leading to percolation agrees with the 1 : 3 TBP : HNO3 ratio reported in the experimental literature for TBP/HNO3/H2O third phases. More generally, the network analysis of cluster formation from atomic

  9. Methodology for risk analysis of projects

    Directory of Open Access Journals (Sweden)

    Roșu Maria Magdalena

    2017-01-01

    Full Text Available The risk in the organization activity as an economic and social system open, adaptive, with varying degrees of permeability to the influences from the current business environment, which is increasingly unpredictable and in which the only constant is the change, refers to the probability of not complying with the objectives set in terms of performance, execution and cost. The insufficient application of the recognized project management methodologies can be one of the main causes of projects failures in the organization with major influences on the activity efficiency and the performance recorded. Therefore, the methodology proposed in the paper, wants to be an effective tool, a formalized risk management tool, considered as a cyclical process, with several distinct phases, indispensable to the current organizational practice which should contribute to optimizing the project performance and its successful completion.

  10. Risk Factor Analysis In Oral Cancers

    Directory of Open Access Journals (Sweden)

    Bharti A.R

    1992-01-01

    Full Text Available A case-control study involving 54 cases and 108 matched controls was conducted to find out the association of risk factors like smoking, chewing paan and tobacco and the occurrence of cancers of the oral cavity. More than 80% of the cases were over 40 years of age, with a male: female ratio of 2:1, paan and tobacco chewing were significantly related to the oral cancers (Odds Ratio of 9.3 and 7.8 respectively. Smoking showed a statistically significant relationship with oral cancers among male patients. In addition, the study also established dose-response and time-response relationship these risk factors and oral cancer.

  11. Environmental risk assessment in GMO analysis.

    Science.gov (United States)

    Pirondini, Andrea; Marmiroli, Nelson

    2010-01-01

    Genetically modified or engineered organisms (GMOs, GEOs) are utilised in agriculture, expressing traits of interest, such as insect or herbicide resistance. Soybean, maize, cotton and oilseed rape are the GM crops with the largest acreage in the world. The distribution of GM acreage in the different countries is related with the different positions concerning labelling of GMO products: based on the principle of substantial equivalence, or rather based on the precautionary principle. The paper provides an overview on how the risks associated with release of GMO in the environments can be analysed and predicted, in view of a possible coexistence of GM and non-GM organisms in agriculture.Risk assessment procedures, both qualitative and quantitative, are compared in the context of application to GMOs considering also legislation requirements (Directive 2001/18/EC). Criteria and measurable properties to assess harm for human health and environmental safety are listed, and the possible consequences are evaluated in terms of significance.Finally, a mapping of the possible risks deriving from GMO release is reported, focusing on gene transfer to related species, horizontal gene transfer, direct and indirect effects on non target organisms, development of resistance in target organisms, and effects on biodiversity.

  12. Some limitations of "Risk = Threat x Vulnerability x Consequence" for risk analysis of terrorist attacks.

    Science.gov (United States)

    Cox, Louis Anthony Tony

    2008-12-01

    Several important risk analysis methods now used in setting priorities for protecting U.S. infrastructures against terrorist attacks are based on the formula: Risk = Threat x Vulnerability x Consequence. This article identifies potential limitations in such methods that can undermine their ability to guide resource allocations to effectively optimize risk reductions. After considering specific examples for the Risk Analysis and Management for Critical Asset Protection (RAMCAP) framework used by the Department of Homeland Security, we address more fundamental limitations of the product formula. These include its failure to adjust for correlations among its components, nonadditivity of risks estimated using the formula, inability to use risk-scoring results to optimally allocate defensive resources, and intrinsic subjectivity and ambiguity of Threat, Vulnerability, and Consequence numbers. Trying to directly assess probabilities for the actions of intelligent antagonists instead of modeling how they adaptively pursue their goals in light of available information and experience can produce ambiguous or mistaken risk estimates. Recent work demonstrates that two-level (or few-level) hierarchical optimization models can provide a useful alternative to Risk = Threat x Vulnerability x Consequence scoring rules, and also to probabilistic risk assessment (PRA) techniques that ignore rational planning and adaptation. In such two-level optimization models, defender predicts attacker's best response to defender's own actions, and then chooses his or her own actions taking into account these best responses. Such models appear valuable as practical approaches to antiterrorism risk analysis.

  13. Public understanding of hydrogen energy. A theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Sherry-Brennan, Fionnguala; Devine-Wright, Hannah; Devine-Wright, Patrick [Manchester Architecture Research Centre (MARC), University of Manchester, Humanities Bridgeford Street, Oxford Road, Manchester M13 9PL (United Kingdom)

    2010-10-15

    The aim of this paper was to investigate public understanding of hydrogen energy using a particular social-psychological theory, namely, the theory of social representations to explore how processes of understanding generated lay knowledge of hydrogen energy. Using a free association method for data collection and multidimensional scaling for analysis, the results enabled the identification of themes in the data such as energy, environment, community, science, and technology, and people and place, around which understanding was based. Processes of representation, such as anchoring to pre-existing knowledge, were seen as essential in guiding understanding. The results indicated that there were diverse influences involved in understanding and, although risk perception of hydrogen was acknowledged, community concerns were seen to override any negative effect of focussing on risk. The role of emotion in decision-making was highlighted as positive emotional responses to the Promoting Unst's Renewable Energy (PURE), a local hydrogen storage project, resulted in hydrogen energy generally being positively evaluated despite acknowledged risks posed by hydrogen such as its explosiveness and flammability. Recommendations for policy include recognising that the combination of expert and lay knowledge plays an important role in public acceptance or rejection of hydrogen energy. (author)

  14. Public understanding of hydrogen energy: A theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Sherry-Brennan, Fionnguala, E-mail: fionnguala@manchester.ac.u [Manchester Architecture Research Centre (MARC), University of Manchester, Humanities Bridgeford Street, Oxford Road, Manchester M13 9PL (United Kingdom); Devine-Wright, Hannah; Devine-Wright, Patrick [Manchester Architecture Research Centre (MARC), University of Manchester, Humanities Bridgeford Street, Oxford Road, Manchester M13 9PL (United Kingdom)

    2010-10-15

    The aim of this paper was to investigate public understanding of hydrogen energy using a particular social-psychological theory, namely, the theory of social representations to explore how processes of understanding generated lay knowledge of hydrogen energy. Using a free association method for data collection and multidimensional scaling for analysis, the results enabled the identification of themes in the data such as energy, environment, community, science, and technology, and people and place, around which understanding was based. Processes of representation, such as anchoring to pre-existing knowledge, were seen as essential in guiding understanding. The results indicated that there were diverse influences involved in understanding and, although risk perception of hydrogen was acknowledged, community concerns were seen to override any negative effect of focussing on risk. The role of emotion in decision-making was highlighted as positive emotional responses to the Promoting Unst's Renewable Energy (PURE), a local hydrogen storage project, resulted in hydrogen energy generally being positively evaluated despite acknowledged risks posed by hydrogen such as its explosiveness and flammability. Recommendations for policy include recognising that the combination of expert and lay knowledge plays an important role in public acceptance or rejection of hydrogen energy.

  15. Analysis of Alternatives for Risk Assessment Methodologies and Tools

    Energy Technology Data Exchange (ETDEWEB)

    Nachtigal, Noel M. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). System Analytics; Fruetel, Julia A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Systems Research and Analysis; Gleason, Nathaniel J. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Systems Research and Analysis; Helms, Jovana [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Systems Research and Analysis; Imbro, Dennis Raymond [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Systems Research and Analysis; Sumner, Matthew C. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Systems Research and Analysis

    2013-10-01

    The purpose of this document is to provide a basic overview and understanding of risk assessment methodologies and tools from the literature and to assess the suitability of these methodologies and tools for cyber risk assessment. Sandia National Laboratories (SNL) performed this review in support of risk modeling activities performed for the Stakeholder Engagement and Cyber Infrastructure Resilience (SECIR) division of the Department of Homeland Security (DHS) Office of Cybersecurity and Communications (CS&C). The set of methodologies and tools covered in this document is not intended to be exhaustive; instead, it focuses on those that are commonly used in the risk assessment community. The classification of methodologies and tools was performed by a group of analysts with experience in risk analysis and cybersecurity, and the resulting analysis of alternatives has been tailored to address the needs of a cyber risk assessment.

  16. Development of economic consequence methodology for process risk analysis.

    Science.gov (United States)

    Zadakbar, Omid; Khan, Faisal; Imtiaz, Syed

    2015-04-01

    A comprehensive methodology for economic consequence analysis with appropriate models for risk analysis of process systems is proposed. This methodology uses loss functions to relate process deviations in a given scenario to economic losses. It consists of four steps: definition of a scenario, identification of losses, quantification of losses, and integration of losses. In this methodology, the process deviations that contribute to a given accident scenario are identified and mapped to assess potential consequences. Losses are assessed with an appropriate loss function (revised Taguchi, modified inverted normal) for each type of loss. The total loss is quantified by integrating different loss functions. The proposed methodology has been examined on two industrial case studies. Implementation of this new economic consequence methodology in quantitative risk assessment will provide better understanding and quantification of risk. This will improve design, decision making, and risk management strategies. © 2014 Society for Risk Analysis.

  17. Management of Microbiologically Influenced Corrosion in Risk Based Inspection analysis

    DEFF Research Database (Denmark)

    Skovhus, Torben Lund; Hillier, Elizabeth; Andersen, Erlend S.

    2016-01-01

    Operating offshore oil and gas production facilities is often associated with high risk. In order to manage the risk, operators commonly use aids to support decision making in the establishment of a maintenance and inspection strategy. Risk Based Inspection (RBI) analysis is widely used...... in the offshore industry as a means to justify the inspection strategy adopted. The RBI analysis is a decision-making technique that enables asset managers to identify the risk related to failure of their most critical systems and components, with an effect on safety, environmental and business related issues...... and an extensive up-to date literature study. The parameters are discussed and subsequently combined in a novel procedure that allows assessment of MIC in a RBI analysis. The procedure is sub-divided into one screening step and a detailed assessment, which fits the recommended approach to assess risk in a RBI...

  18. Cost-benefit analysis of the african risk capacity facility:

    OpenAIRE

    Clarke, Daniel J; Hill, Ruth Vargas

    2013-01-01

    The African Risk Capacity (ARC), has been proposed as a pan-Africa drought risk pool to insure against drought risk in Africa south of the Sahara. If fully operationalized, the ARC will mark a major change in how donors fund emergency support to countries in Africa during times of need. In this paper, we undertake a cost-benefit analysis of the ARC pool and discuss how lessons can inform the design of the ARC.

  19. RISK ANALYSIS IN CONSTRUCTION PROJECTS: A PRACTICAL SELECTION METHODOLOGY

    OpenAIRE

    Alberto De Marco; Muhammad Jamaluddin Thaheem

    2014-01-01

    Project Risk Management (PRM) is gaining attention from researchers and practitioners in the form of sophisticated tools and techniques to help construction managers perform risk management. However, the large variety of techniques has made selecting an appropriate solution a complex and risky task in itself. Accordingly, this study proposes a practical framework methodology to assist construction project managers and practitioners in choosing a suitable risk analysis technique based on selec...

  20. Risk Analysis for Resource Planning Optimization

    Science.gov (United States)

    Cheung, Kar-Ming

    2008-01-01

    This paper describes a systems engineering approach to resource planning by integrating mathematical modeling and constrained optimization, empirical simulation, and theoretical analysis techniques to generate an optimal task plan in the presence of uncertainties.

  1. Risk and safety analysis of nuclear systems

    National Research Council Canada - National Science Library

    Lee, John C; McCormick, Norman J

    2011-01-01

    ...), and failure modes of systems. All of this material is general enough that it could be used in non-nuclear applications, although there is an emphasis placed on the analysis of nuclear systems...

  2. A continuum damage analysis of hydrogen attack in 2.25 Cr-1Mo vessel

    DEFF Research Database (Denmark)

    van der Burg, M.W.D.; van der Giessen, E.; Tvergaard, Viggo

    1998-01-01

    reaction of carbides with hydrogen, thus forming cavities with high pressure methane gas. Driven by the methane gas pressure, the cavities grow, while remote tensile stresses can significantly enhance the cavitation rate. The damage model gives the strain-rate and damage rate as a function...... and later decelerate the cavitation rate significantly. Numerical studies for different material parameters and different stress conditions demonstrate the HA process inside a vessel in time. Also, the lifetime of the pressure vessel is determined. The analyses underline that the general applicability...

  3. Optimization of source-sample-detector geometries for bulk hydrogen analysis using epithermal neutrons.

    Science.gov (United States)

    Csikai, J; Dóczi, R

    2009-01-01

    The advantages and limitations of epithermal neutrons in qualification of hydrocarbons via their H contents and C/H atomic ratios have been investigated systematically. Sensitivity of this method and the dimensions of the interrogated regions were determined for various types of hydrogenous samples. Results clearly demonstrate the advantages of direct neutron detection, e.g. by BF(3) counters as compared to the foil activation method in addition to using the hardness of the spectral shape of Pu-Be neutrons to that from a (252)Cf source.

  4. Analysis of the Quasi-Elastic Scattering of Neutrons in Hydrogenous Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Porohit, S.N. [Nuclear Science and Engineering Dept., Rensselaer Polytechnique Inst., Troy, NY (United States)

    1966-11-15

    A critical discussion of the quasi-elastic scattering of neutrons by incoherent (hydrogenous) liquids is presented. Using the line shape expression a comparative discussion of several phenomenological models has been carried out. Extension of the Singwi-Sjoelander zero phonon expression, for the jump-diffusion model, so as to include the one phonon expression has also been given. For a delayed diffusion model a complete treatment of S(K, {omega}) is presented. Along the lines of the macroscopic diffusion cooling, a microscopic diffusion cooling effect in fluids is speculated.

  5. The use of current risk analysis tools evaluated towards preventing external domino accidents

    NARCIS (Netherlands)

    Reniers, Genserik L L; Dullaert, W.; Ale, B. J.M.; Soudan, K.

    Risk analysis is an essential tool for company safety policy. Risk analysis consists of identifying and evaluating all possible risks. The efficiency of risk analysis tools depends on the rigueur of identifying and evaluating all possible risks. The diversity in risk analysis procedures is such that

  6. The JPL Cost Risk Analysis Approach that Incorporates Engineering Realism

    Science.gov (United States)

    Harmon, Corey C.; Warfield, Keith R.; Rosenberg, Leigh S.

    2006-01-01

    This paper discusses the JPL Cost Engineering Group (CEG) cost risk analysis approach that accounts for all three types of cost risk. It will also describe the evaluation of historical cost data upon which this method is based. This investigation is essential in developing a method that is rooted in engineering realism and produces credible, dependable results to aid decision makers.

  7. Risk analysis of early childhood eczema

    DEFF Research Database (Denmark)

    Bisgaard, Hans; Halkjaer, Liselotte B; Hinge, Rikke

    2009-01-01

    assessments included filaggrin loss-of-function mutation; parent's atopic disease; sex; social status; previous deliveries; third trimester complications and exposures; anthropometrics at birth; month of birth; duration solely breast-fed; introduction of egg, cow's milk, and fish; time spent in day care; cat......: The Copenhagen Study on Asthma in Childhood is a prospective clinical study of a birth cohort of 411 children born of mothers with asthma. Eczema was diagnosed, treated, and monitored at the clinical research unit, and complete follow-up for the first 3 years of life was available for 356 children. Risk...

  8. Vulnerability and Risk Analysis Program: Overview of Assessment Methodology

    National Research Council Canada - National Science Library

    2001-01-01

    .... Over the last three years, a team of national laboratory experts, working in partnership with the energy industry, has successfully applied the methodology as part of OCIP's Vulnerability and Risk Analysis Program (VRAP...

  9. Simulation Approach to Mission Risk and Reliability Analysis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — It is proposed to develop and demonstrate an integrated total-system risk and reliability analysis approach that is based on dynamic, probabilistic simulation. This...

  10. Hierarchical Modelling of Flood Risk for Engineering Decision Analysis

    DEFF Research Database (Denmark)

    Custer, Rocco

    to changing flood risk. In the presence of flood protection structures, flood development depends on the state of all protection structures in the system. As such, hazard is a function not only of rainfall and river discharge, but also of protection structures’ fragility. A methodology for flood risk analysis...... and decision analysis for hierarchical flood protection systems is proposed, which allows for joint consideration of hazard models and fragility models of protection structures. In the implementation of the flood risk analysis methodology several challenges are identified, two of which are addressed...... systems, as well as the implementation of the flood risk analysis methodology and the vulnerability modelling approach are illustrated with an example application. In summary, the present thesis provides a characterisation of hierarchical flood protection systems as well as several methodologies to model...

  11. Risk and Interdependencies in Critical Infrastructures A Guideline for Analysis

    CERN Document Server

    Utne, Ingrid; Vatn, Jørn

    2012-01-01

    Today’s society is completely dependent on critical networks such as  water supply, sewage, electricity, ICT and transportation. Risk and vulnerability analyses are needed to grasp the impact of threats and hazards. However, these become quite complex as there are strong interdependencies both within and between infrastructure systems. Risk and Interdependencies in Critical Infrastructures: A  guideline for analysis provides methods for analyzing risks and interdependencies of critical infrastructures.  A number of analysis approaches are described and are adapted to each of these infrastructures. Various approaches are also revised, and all are supported by several examples and illustrations. Particular emphasis is given to the analysis of various interdependencies that often exist between the infrastructures.  Risk and Interdependencies in Critical Infrastructures: A  guideline for analysis provides a good tool to identify the hazards that are threatening your infrastructures, and will enhance the un...

  12. Evaluation of rail test frequencies using risk analysis

    Science.gov (United States)

    2009-03-03

    Several industries now use risk analysis to develop : inspection programs to ensure acceptable mechanical integrity : and reliability. These industries include nuclear and electric : power generation, oil refining, gas processing, onshore and : offsh...

  13. Dynamical study, hydrogen bond analysis, and constant pH simulations of the beta carbonic anhydrase of Methanobacterium thermoautotrophicum.

    Science.gov (United States)

    Bracht, Fabrício; de Alencastro, Ricardo Bicca

    2016-01-01

    Within the five classes (α, β, γ, δ, and ζ) of carbonic anhydrases (CAs) the first two, containing mammal and plant representatives, are the most studied among all CAs. In this study, we have focused our investigation on the beta-class carbonic anhydrase of Methanobacterium thermoautotrophicum. We investigated both the importance of the Asp-Arg dyad near the catalytic zinc-bound water and the possible roles that water molecules within the active site and residues near the entrance of the catalytic cleft have on the first step of the enzyme's reaction mechanism. Hydrogen-bonding analysis of selected residues within the active site and constant pH replica exchange molecular dynamics constant pH replica exchange simulations were performed. The latter was done in order to evaluate the pKa values of possible proton acceptors. We found an intricate hydrogen-bonding network involving two acidic residues within the active site, Asp16 and Asp34, and the catalytic water molecule. We also observed a very strong interaction between the zinc-bound water and residues Asp34 and Arg36. This interaction was not significantly affected by the change in the protonation state of both the catalytic water and aspartate residue 34. The pKa analysis show that the effect of the R36A mutation affects not only the possible proton acceptors, but also the catalytic water itself.

  14. Latent Model Analysis of Substance Use and HIV Risk Behaviors among High-Risk Minority Adults

    Science.gov (United States)

    Wang, Min Qi; Matthew, Resa F.; Chiu, Yu-Wen; Yan, Fang; Bellamy, Nikki D.

    2007-01-01

    Objectives: This study evaluated substance use and HIV risk profile using a latent model analysis based on ecological theory, inclusive of a risk and protective factor framework, in sexually active minority adults (N=1,056) who participated in a federally funded substance abuse and HIV prevention health initiative from 2002 to 2006. Methods: Data…

  15. Cyclic Performance Analysis of Hydrogen/Bromine Flow Batteries for Grid-Scale Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Cho, KT; Tucker, MC; Ding, M; Ridgway, P; Battaglia, VS; Srinivasan, V; Weber, AZ

    2014-06-03

    This paper explores the critical factors dominating the cycle performance of the hydrogen/bromine redox flow battery (RFB). Carbon electrode oxidation to CO2 was seen as the dominant side reaction, which can be prevented by operating the cell below 1.4 V. Crossover of bromide species from the positive to the negative electrode, especially during charge, dominates the coulombic efficiency, and can result in dissolution of the Pt catalyst if an adequate hydrogen supply is not maintained. This paper also describes the tradeoffs in voltaic, energy, and coulombic efficiencies during cycling, including the determination of the peak energy efficiency with respect to the HBr concentration and current density. Long-term cycling demonstrates negligible cell-component degradation over 600 cycles (approximate to 3 months), with capacity loss caused by the bromine from the system, which can be mitigated by proper system design. The data and methodologies provided in this paper can be used to understand better the operation of this and other RFBs.

  16. Permeability test and fuzzy orthogonal analysis of hydrogenated nitrile O-ring

    Directory of Open Access Journals (Sweden)

    Qin Hu

    2015-03-01

    Full Text Available In the high temperature, high pressure and high corrosive environment of the oil and gas drilling downhole, the weatherability of rubber sealing material has a great influence on the production safety. In order to study the important degree of every key environmental factor in downhole influencing the sealing performance of rubber sealing material, a new device of simulating downhole environment is designed to test the permeability of O-ring. The sample is hydrogenated nitrile O-ring and orthogonal experiment method is used to do nine tests by getting three levels from temperature, pressure and CO2 volume fraction. Test adopts fuzzy orthogonal method to analyze the main effects and the interaction between two factors, taking tensile strength, diameter variety rate and pH value of indicator as evaluation index. The results show that: the environmental factor influencing the sealing performance of hydrogenated nitrile O-ring from high to low by turns is temperature, pressure and CO2 volume fraction, while the interaction between temperature and pressure is the most significant. It provides a new way to study the influence of downhole complex environment on the performance of rubber sealing material. Moreover, the results have important reference value to further study the failure mechanism of rubber sealing ring in many environmental factors and the rational use in engineering.

  17. Thermodynamic Analysis of Three Compressed Air Energy Storage Systems: Conventional, Adiabatic, and Hydrogen-Fueled

    Directory of Open Access Journals (Sweden)

    Hossein Safaei

    2017-07-01

    Full Text Available We present analyses of three families of compressed air energy storage (CAES systems: conventional CAES, in which the heat released during air compression is not stored and natural gas is combusted to provide heat during discharge; adiabatic CAES, in which the compression heat is stored; and CAES in which the compression heat is used to assist water electrolysis for hydrogen storage. The latter two methods involve no fossil fuel combustion. We modeled both a low-temperature and a high-temperature electrolysis process for hydrogen production. Adiabatic CAES (A-CAES with physical storage of heat is the most efficient option with an exergy efficiency of 69.5% for energy storage. The exergy efficiency of the conventional CAES system is estimated to be 54.3%. Both high-temperature and low-temperature electrolysis CAES systems result in similar exergy efficiencies (35.6% and 34.2%, partly due to low efficiency of the electrolyzer cell. CAES with high-temperature electrolysis has the highest energy storage density (7.9 kWh per m3 of air storage volume, followed by A-CAES (5.2 kWh/m3. Conventional CAES and CAES with low-temperature electrolysis have similar energy densities of 3.1 kWh/m3.

  18. ANALYSIS OF RISK FACTORS ECTOPIC PREGNANCY

    Directory of Open Access Journals (Sweden)

    Budi Santoso

    2017-04-01

    Full Text Available Introduction: Ectopic pregnancy is a pregnancy with extrauterine implantation. This situation is gynecologic emergency that contributes to maternal mortality. Therefore, early recognition, based on identification of the causes of ectopic pregnancy risk factors, is needed. Methods: The design descriptive observational. The samples were pregnant women who had ectopic pregnancy at Maternity Room, Emergency Unit, Dr. Soetomo Hospital, Surabaya, from 1 July 2008 to 1 July 2010. Sampling technique was total sampling using medical records. Result: Patients with ectopic pregnancy were 99 individuals out of 2090 pregnant women who searched for treatment in Dr. Soetomo Hospital. However, only 29 patients were accompanied with traceable risk factors. Discussion:. Most ectopic pregnancies were in the age group of 26-30 years, comprising 32 patients (32.32%, then in age groups of 31–35 years as many as 25 patients (25.25%, 18 patients in age group 21–25 years (18.18%, 17 patients in age group 36–40 years (17.17%, 4 patients in age group 41 years and more (4.04%, and the least was in age group of 16–20 years with 3 patients (3.03%. A total of 12 patients with ectopic pregnancy (41.38% had experience of abortion and 6 patients (20.69% each in groups of patients with ectopic pregnancy who used family planning, in those who used family planning as well as ectopic pregnancy patients with history of surgery. There were 2 patients (6.90% of the group of patients ectopic pregnancy who had history of surgery and history of abortion. The incidence rate of ectopic pregnancy was 4.73%, mostly in the second gravidity (34.34%, whereas the nulliparous have the highest prevalence of 39.39%. Acquired risk factors, i.e. history of operations was 10.34%, patients with family planning 20.69%, patients with history of abortion 41.38%, patients with history of abortion and operation 6.90% patients with family and history of abortion was 20.69%.

  19. Socioeconomic Considerations in Dam Safety Risk Analysis.

    Science.gov (United States)

    1987-06-01

    techniques are compared. The application of eco - nomic principles to the analysis of water projects is, of course, well ,p.~-*..’. ,~. -. . - 5 delineated...aniciateddirct lss s 25perent r mre-o°th commnitys sock f reid ialand ommrcia captal "o 44 which destroy a sizable percentage of the region’s industrial

  20. Quantitative risk analysis in two pipelines operated by TRANSPETRO

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Claudio B. [PETROBRAS Transporte S/A (TRANSPETRO), Rio de Janeiro, RJ (Brazil); Pinho, Edson [Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropedica, RJ (Brazil); Bittencourt, Euclides [Centro Universitario FIB, Salvador , BA (Brazil)

    2009-07-01

    Transportation risk analysis techniques were used to study two pipelines operated by TRANSPETRO. The Pipeline A is for the simultaneous transportation of diesel, gasoline and LPG and comprises three parts, all of them crossing rural areas. The Pipeline B is for oil transportation and one of its ends is located in an area of a high density population. Both pipelines had their risk studied using the PHAST RISK{sup R} software and the individual risk measures, the only considered measures for license purposes for this type of studies, presented level far below the maximum tolerable levels considered. (author)

  1. THE ANALYSIS OF RISK MANAGEMENT PROCESS WITHIN MANAGEMENT

    Directory of Open Access Journals (Sweden)

    ROMANESCU MARCEL LAURENTIU

    2016-10-01

    Full Text Available This article highlights the risk analysis within management, focusing on how a company could practicaly integrate the risks management in the existing leading process. Subsequently, it is exemplified the way of manage risk effectively, which gives numerous advantages to all firms, including improving their decision-making process. All these lead to the conclusion that the degree of risk specific to companies is very high, but if managers make the best decisions then it can diminish it and all business activitiy and its income are not influenced by factors that could disturb in a negative way .

  2. An analysis of the thermodynamic cycles with high-temperature nuclear reactor for power generation and hydrogen co-production

    Directory of Open Access Journals (Sweden)

    Dudek Michał

    2017-01-01

    Full Text Available In the present paper, numerical analysis of the thermodynamic cycle with the high-temperature nuclear gas reactor (HTGR for electricity and hydrogen production have been done. The analysed system consists of two independent loops. The first loop is for HTGR and consists of a nuclear reactor, heat exchangers, and blower. The second loop (Rankine cycle consist of up-to four steam turbines, that operate in heat recovery system. The analysis of the system shows that it is possible to achieve significantly higher efficiency than could be offered by traditional nuclear reactor technology (PWR and BWR. It is shown that the thermal efficiency about 52.5% it is possible to achieve when reactor works at standard conditions and steam is superheated up to 530oC. For the cases when the steam has supercritical conditions the value of thermal efficiency is still very high and equal about 50%.

  3. Environmental risk analysis of hazardous material rail transportation.

    Science.gov (United States)

    Saat, Mohd Rapik; Werth, Charles J; Schaeffer, David; Yoon, Hongkyu; Barkan, Christopher P L

    2014-01-15

    An important aspect of railroad environmental risk management involves tank car transportation of hazardous materials. This paper describes a quantitative, environmental risk analysis of rail transportation of a group of light, non-aqueous-phase liquid (LNAPL) chemicals commonly transported by rail in North America. The Hazardous Materials Transportation Environmental Consequence Model (HMTECM) was used in conjunction with a geographic information system (GIS) analysis of environmental characteristics to develop probabilistic estimates of exposure to different spill scenarios along the North American rail network. The risk analysis incorporated the estimated clean-up cost developed using the HMTECM, route-specific probability distributions of soil type and depth to groundwater, annual traffic volume, railcar accident rate, and tank car safety features, to estimate the nationwide annual risk of transporting each product. The annual risk per car-mile (car-km) and per ton-mile (ton-km) was also calculated to enable comparison between chemicals and to provide information on the risk cost associated with shipments of these products. The analysis and the methodology provide a quantitative approach that will enable more effective management of the environmental risk of transporting hazardous materials. Published by Elsevier B.V.

  4. Risk-benefit analysis and public policy: a bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Clark, E.M.; Van Horn, A.J.

    1976-11-01

    Risk-benefit analysis has been implicitly practiced whenever decision-makers are confronted with decisions involving risks to life, health, or to the environment. Various methodologies have been developed to evaluate relevant criteria and to aid in assessing the impacts of alternative projects. Among these have been cost-benefit analysis, which has been widely used for project evaluation. However, in many cases it has been difficult to assign dollar costs to those criteria involving risks and benefits which are not now assigned explicit monetary values in our economic system. Hence, risk-benefit analysis has evolved to become more than merely an extension of cost-benefit analysis, and many methods have been applied to examine the trade-offs between risks and benefits. In addition, new scientific and statistical techniques have been developed for assessing current and future risks. The 950 references included in this bibliography are meant to suggest the breadth of those methodologies which have been applied to decisions involving risk.

  5. APPROPRIATE ALLOCATION OF CONTINGENCY USING RISK ANALYSIS METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Andi Andi

    2004-01-01

    Full Text Available Many cost overruns in the world of construction are attributable to either unforeseen events or foreseen events for which uncertainty was not appropriately accommodated. It is argued that a significant improvement to project management performance may result from greater attention to the process of analyzing project risks. The objective of this paper is to propose a risk analysis methodology for appropriate allocation of contingency in project cost estimation. In the first step, project risks will be identified. Influence diagramming technique is employed to identify and to show how the risks affect the project cost elements and also the relationships among the risks themselves. The second step is to assess the project costs with regards to the risks under consideration. Using a linguistic approach, the degree of uncertainty of identified project risks is assessed and quantified. The problem of dependency between risks is taken into consideration during this analysis. For the final step, as the main purpose of this paper, a method for allocating appropriate contingency is presented. Two types of contingencies, i.e. project contingency and management reserve are proposed to accommodate the risks. An illustrative example is presented at the end to show the application of the methodology.

  6. Analysis of labour risks in the Spanish industrial aerospace sector.

    Science.gov (United States)

    Laguardia, Juan; Rubio, Emilio; Garcia, Ana; Garcia-Foncillas, Rafael

    2016-01-01

    Labour risk prevention is an activity integrated within Safety and Hygiene at Work in Spain. In 2003, the Electronic Declaration for Accidents at Work, Delt@ (DELTA) was introduced. The industrial aerospace sector is subject to various risks. Our objective is to analyse the Spanish Industrial Aerospace Sector (SIAS) using the ACSOM methodology to assess its labour risks and to prioritise preventive actions. The SIAS and the Services Subsector (SS) were created and the relevant accident rate data were obtained. The ACSOM method was applied through double contrast (deviation and translocation) of the SIAS or SS risk polygon with the considered pattern, accidents from all sectors (ACSOM G) or the SIAS. A list of risks was obtained, ordered by action phases. In the SIAS vs. ACSOM G analysis, radiation risks were the worst, followed by overstrains. Accidents caused by living beings were also significant in the SS vs. SIAE, which will be able to be used to improve Risk Prevention. Radiation is the most significant risk in the SIAS and the SS. Preventive actions will be primary and secondary. ACSOM has shown itself to be a valid tool for the analysis of labour risks.

  7. A continuum damage analysis of hydrogen attack in a 2.25Cr–1Mo pressure vessel

    NARCIS (Netherlands)

    Burg, M.W.D. van der; Giessen, E. van der; Tvergaard, V.

    1998-01-01

    A micromechanically based continuum damage model is presented to analyze the stress, temperature and hydrogen pressure dependent material degradation process termed hydrogen attack, inside a pressure vessel. Hydrogen attack (HA) is the damage process of grain boundary facets due to a chemical

  8. Analysis of Hydrogen Isotopic Exchange: Lava Creek Tuff Ash and Isotopically Labeled Water

    Science.gov (United States)

    Ross, A. M.; Seligman, A. N.; Bindeman, I. N.; Nolan, G. S.

    2015-12-01

    Nolan and Bindeman (2013) placed secondarily hydrated ash from the 7.7 ka eruption of Mt. Mazama (δD=-149‰, 2.3wt% H2Ot) in isotopically labeled water (+650 ‰ δD, +56 ‰ δ18O) and observed that the H2Ot and δ18O values remained constant, but the δD values of ash increased with the surrounding water at 20, 40 and 70 °C. We expand on this work by conducting a similar experiment with ash from the 640 ka Lava Creek Tuff (LCT, δD of -128 ‰; 2.1 wt.% H2Ot) eruption of Yellowstone to see if significantly older glass (with a hypothesized gel layer on the surface shielding the interior from alteration) produces the same results. We have experiments running at 70, 24, and 5 °C, and periodically remove ~1.5 mg of glass to measure the δD (‰) and H2Ot (wt.%) of water extracted from the glass on a TC/EA MAT 253 continuous flow system. After 600 hours, the δD of the samples left at 5 and 24 °C remains at -128 ‰, but increased 8‰ for the 70 °C run series. However, there is no measurable change in wt.% of H2Ot, indicating that hydrogen exchange is not dictated by the addition of water. We are measuring and will report further progress of isotope exchange. We also plan to analyze the water in the LCT glass for δ18O (‰) to see if, as is the case for the Mt. Mazama glass, the δ18O (‰) remains constant. We also analyzed Mt. Mazama glass from the Nolan and Bindeman (2013) experiments that have now been sitting in isotopically labeled water at room temperature for ~5 years. The water concentration is still unchanged (2.3 wt.% H2Ot), and the δD of the water in the glass is now -111 ‰, causing an increase of 38 ‰. Our preliminary results show that exchange of hydrogen isotopes of hydrated glass is not limited by the age of the glass, and that the testing of hydrogen isotopes of secondarily hydrated glass, regardless of age, may not be a reliable paleoclimate indicator.

  9. Development of a risk-analysis model. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1979-10-01

    This report consists of a main body, which provides a presentation of risk analysis and its general and specific application to the needs of the Office of Buildings and Community Systems of the Department of Energy; and several case studies employing the risk-analysis model developed. The highlights include a discussion of how risk analysis is currently used in the private, regulated, and public sectors and how this methodology can be employed to meet the policy-analysis needs of the Office of Buildings and Community Systems of the Department of Energy (BCS/DOE). After a review of the primary methodologies available for risk analysis, it was determined that Monte Carlo simulation techniques provide the greatest degree of visibility into uncertainty in the decision-making process. Although the data-collection requirements can be demanding, the benefits, when compared to other methods, are substantial. The data-collection problem can be significantly reduced, without sacrificing proprietary-information rights, if prior arrangements are made with RD and D contractors to provide responses to reasonable requests for base-case data. A total of three case studies were performed on BCS technologies: a gas-fired heat pump; a 1000 ton/day anaerobic digestion plant; and a district heating and cooling system. The three case studies plus the risk-analysis methodology were issued as separate reports. It is concluded that, based on the overall research of risk analysis and the case-study experience, that the risk-analysis methodology has significant potential as a policy-evaluation tool within BCS.

  10. Geotechnical risk analysis by flat dilatometer (DMT)

    Science.gov (United States)

    Amoroso, Sara; Monaco, Paola

    2015-04-01

    In the last decades we have assisted at a massive migration from laboratory testing to in situ testing, to the point that, today, in situ testing is often the major part of a geotechnical investigation. The State of the Art indicates that direct-push in situ tests, such as the Cone Penetration Test (CPT) and the Flat Dilatometer Test (DMT), are fast and convenient in situ tests for routine site investigation. In most cases the DMT estimated parameters, in particular the undrained shear strength su and the constrained modulus M, are used with the common design methods of Geotechnical Engineering for evaluating bearing capacity, settlements etc. The paper focuses on the prediction of settlements of shallow foundations, that is probably the No. 1 application of the DMT, especially in sands, where undisturbed samples cannot be retrieved, and on the risk associated with their design. A compilation of documented case histories that compare DMT-predicted vs observed settlements, was collected by Monaco et al. (2006), indicating that, in general, the constrained modulus M can be considered a reasonable "operative modulus" (relevant to foundations in "working conditions") for settlement predictions based on the traditional linear elastic approach. Indeed, the use of a site investigation method, such as DMT, that improve the accuracy of design parameters, reduces risk, and the design can then center on the site's true soil variability without parasitic test variability. In this respect, Failmezger et al. (1999, 2015) suggested to introduce Beta probability distribution, that provides a realistic and useful description of variability for geotechnical design problems. The paper estimates Beta probability distribution in research sites where DMT tests and observed settlements are available. References Failmezger, R.A., Rom, D., Ziegler, S.R. (1999). "SPT? A better approach of characterizing residual soils using other in-situ tests", Behavioral Characterics of Residual Soils, B

  11. Authenticity and Traceability of Vanilla Flavors by Analysis of Stable Isotopes of Carbon and Hydrogen

    DEFF Research Database (Denmark)

    Hansen, Anne-Mette Sølvbjerg; Fromberg, Arvid; Frandsen, Henrik Lauritz

    2014-01-01

    to differentiate these two groups of natural vanillin from vanillin produced otherwise. Vanilla flavors were also analyzed for ratios of hydrogen stable isotopes (delta H-2). A graphic representation of delta C-13 versus delta H-2 revealed that vanillin extracted from pods grown in adjacent geographic origins......Authenticity and traceability of vanilla flavors were investigated using gas chromatographyisotope ratio mass spectrometry (GC-IRMS). Vanilla flavors produced by chemical synthesis (n = 2), fermentation (n = 1), and extracted from two different species of the vanilla orchid (n = 79) were analyzed....... The authenticity of the flavor compound vanillin was evaluated on the basis of measurements of ratios of carbon stable isotopes (delta C-13). It was found that results of delta C-13 for vanillin extracted from Vanilla planifolia and Vanilla tahitensis were significantly different (t test) and that it was possible...

  12. Hydrogen-induced program threshold voltage degradation analysis in SONOS wafer

    Science.gov (United States)

    Lin, Qing; Zhao, Crystal; Sheng, Nan

    2016-02-01

    This paper studies the hydrogen-induced program state threshold voltage degradation in SONOS wafers, which ultimately impacts wafer sort test yield. During wafer sort step, all individual integrated circuits noted as die are tested for functional defects by applying special test patterns to them. The proportion between the passing die (good die) and the non-passing die (bad die) is sort yield. The different N2/H2 ratio in IMD1 alloy process yields differently at flash checkerboard test. And the SIMS curves were also obtained to depict the distribution profile of H+ in SONOS ONO stack structure. It is found that, the H+ accumulated in the interface between the Tunnel oxide and Si layer, contributes the charge loss in Oxynitride layer, which leads to the program threshold voltage degradation and even fall below lower specification limit, and then impacts the sort yield of SONOS wafers.

  13. Hydrogen Embrittlement

    Science.gov (United States)

    Woods, Stephen; Lee, Jonathan A.

    2016-01-01

    Hydrogen embrittlement (HE) is a process resulting in a decrease in the fracture toughness or ductility of a metal due to the presence of atomic hydrogen. In addition to pure hydrogen gas as a direct source for the absorption of atomic hydrogen, the damaging effect can manifest itself from other hydrogen-containing gas species such as hydrogen sulfide (H2S), hydrogen chloride (HCl), and hydrogen bromide (HBr) environments. It has been known that H2S environment may result in a much more severe condition of embrittlement than pure hydrogen gas (H2) for certain types of alloys at similar conditions of stress and gas pressure. The reduction of fracture loads can occur at levels well below the yield strength of the material. Hydrogen embrittlement is usually manifest in terms of singular sharp cracks, in contrast to the extensive branching observed for stress corrosion cracking. The initial crack openings and the local deformation associated with crack propagation may be so small that they are difficult to detect except in special nondestructive examinations. Cracks due to HE can grow rapidly with little macroscopic evidence of mechanical deformation in materials that are normally quite ductile. This Technical Memorandum presents a comprehensive review of experimental data for the effects of gaseous Hydrogen Environment Embrittlement (HEE) for several types of metallic materials. Common material screening methods are used to rate the hydrogen degradation of mechanical properties that occur while the material is under an applied stress and exposed to gaseous hydrogen as compared to air or helium, under slow strain rates (SSR) testing. Due to the simplicity and accelerated nature of these tests, the results expressed in terms of HEE index are not intended to necessarily represent true hydrogen service environment for long-term exposure, but rather to provide a practical approach for material screening, which is a useful concept to qualitatively evaluate the severity of

  14. Re-evaluation of melanin bleaching using warm diluted hydrogen peroxide for histopathological analysis.

    Science.gov (United States)

    Momose, Masanobu; Ota, Hiroyoshi; Hayama, Masayoshi

    2011-06-01

    Excessive amounts of melanin pigments may hamper histopathological assessments of melanocytic lesions by obscuring cellular morphology and hindering antibody-antigen interactions. To determine the optimal melanin-bleaching conditions for histopathological examination, heavily pigmented melanomas were treated with warm hydrogen peroxide (H2O2) diluted with various diluents (1% disodium hydrogen phosphate 12H2O (Na2 HPO4); phosphate buffer 0.05 M, pH 7.4 (PB); and PBS 0.05 M, pH 7.4) at varying temperatures (50°C, 55°C, and 60°C) and for varying incubation times (0.5, 1, 2, and 3 h). The effect of the sequential order of antigen retrieval and bleaching on preserving tissue morphology was then evaluated. Additionally, the effect of melanin bleaching using warm diluted H2O2 on the antigenicity of melanoma-related markers (HMB-45, MART-1, and S-100) and other markers used for histopathology was examined in amelanotic melanomas and tonsil tissue. Optimal and complete bleaching was achieved using warm 3% H2O2 in PB treatment at 55°C for 2 h following antigen retrieval with microwaving or digestion with trypsin. Under these conditions, the tissue morphology and antigenicity of various immunohistochemical markers were also well preserved. Bleaching with warm 3% H2O2 PB is a fast and efficient method of bleaching melanin pigments and performing immunohistochemical examination in heavily melanin-pigmented lesions. © 2011 The Authors. Pathology International © 2011 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd.

  15. Sims Analysis of Water Abundance and Hydrogen Isotope in Lunar Highland Plagioclase

    Science.gov (United States)

    Hui, Hejiu; Guan, Yunbin; Chen, Yang; Peslier, Anne H.; Zhang, Youxue; Liu, Yang; Rossman, George R.; Eiler, John M.; Neal, Clive R.

    2015-01-01

    The detection of indigenous water in mare basaltic glass beads has challenged the view established since the Apollo era of a "dry" Moon. Since this discovery, measurements of water in lunar apatite, olivine-hosted melt inclusions, agglutinates, and nominally anhydrous minerals have confirmed that lunar igneous materials contain water, implying that some parts of lunar mantle may have as much water as Earth's upper mantle. The interpretation of hydrogen (H) isotopes in lunar samples, however, is controversial. The large variation of H isotope ratios in lunar apatite (delta Deuterium = -202 to +1010 per mille) has been taken as evidence that water in the lunar interior comes from the lunar mantle, solar wind protons, and/or comets. The very low deuterium/H ratios in lunar agglutinates indicate that solar wind protons have contributed to their hydrogen content. Conversely, H isotopes in lunar volcanic glass beads and olivine-hosted melt inclusions being similar to those of common terrestrial igneous rocks, suggest a common origin for water in both Earth and Moon. Lunar water could be inherited from carbonaceous chondrites, consistent with the model of late accretion of chondrite-type materials to the Moon as proposed by. One complication about the sources of lunar water, is that geologic processes (e.g., late accretion and magmatic degassing) may have modified the H isotope signatures of lunar materials. Recent FTIR analyses have shown that plagioclases in lunar ferroan anorthosite contain approximately 6 ppm H2O. So far, ferroan anorthosite is the only available lithology that is believed to be a primary product of the lunar magma ocean (LMO). A possible consequence is that the LMO could have contained up to approximately 320 ppm H2O. Here we examine the possible sources of water in the LMO through measurements of water abundances and H isotopes in plagioclase of two ferroan anorthosites and one troctolite from lunar highlands.

  16. Approaching risk analysis and risk management in the fertility laboratory and semen bank.

    Science.gov (United States)

    Janssens, Pim M W; Cheung, Kin Sun

    2009-12-01

    Present-day quality consciousness, as reflected in the newest European Directives and guidelines, demands from laboratories working with human gametes and embryos that attention be paid to risk analysis and management. Using these Directives and guidelines as reference, while also aiming at accreditation, we have worked out an approach for risk analysis in the fertility laboratory and semen bank for the processing of semen to be used for intrauterine insemination and for the preservation of semen in the semen bank, based on the general principles of failure mode and effect analysis. In this overview, we describe how risk analyses and various aspects of risk management in the fertility laboratory and semen bank can be carried out.

  17. Impossible Certainty: Cost Risk Analysis for Air Force Systems

    Science.gov (United States)

    2006-01-01

    7 For more detailed information, see, for example, Henrici (1964). 52 Impossible Certainty: Cost Risk Analysis for Air Force Systems... Henrici , Peter, Elements of Numerical Analysis, New York: John Wiley, 1964. Hess, Ronald W., and H. P. Romanoff, Aircraft Airframe Cost Estimating

  18. Revealing the underlying drivers of disaster risk: a global analysis

    Science.gov (United States)

    Peduzzi, Pascal

    2017-04-01

    Disasters events are perfect examples of compound events. Disaster risk lies at the intersection of several independent components such as hazard, exposure and vulnerability. Understanding the weight of each component requires extensive standardisation. Here, I show how footprints of past disastrous events were generated using GIS modelling techniques and used for extracting population and economic exposures based on distribution models. Using past event losses, it was possible to identify and quantify a wide range of socio-politico-economic drivers associated with human vulnerability. The analysis was applied to about nine thousand individual past disastrous events covering earthquakes, floods and tropical cyclones. Using a multiple regression analysis on these individual events it was possible to quantify each risk component and assess how vulnerability is influenced by various hazard intensities. The results show that hazard intensity, exposure, poverty, governance as well as other underlying factors (e.g. remoteness) can explain the magnitude of past disasters. Analysis was also performed to highlight the role of future trends in population and climate change and how this may impacts exposure to tropical cyclones in the future. GIS models combined with statistical multiple regression analysis provided a powerful methodology to identify, quantify and model disaster risk taking into account its various components. The same methodology can be applied to various types of risk at local to global scale. This method was applied and developed for the Global Risk Analysis of the Global Assessment Report on Disaster Risk Reduction (GAR). It was first applied on mortality risk in GAR 2009 and GAR 2011. New models ranging from global assets exposure and global flood hazard models were also recently developed to improve the resolution of the risk analysis and applied through CAPRA software to provide probabilistic economic risk assessments such as Average Annual Losses (AAL

  19. Ontology-based specification, identification and analysis of perioperative risks.

    Science.gov (United States)

    Uciteli, Alexandr; Neumann, Juliane; Tahar, Kais; Saleh, Kutaiba; Stucke, Stephan; Faulbrück-Röhr, Sebastian; Kaeding, André; Specht, Martin; Schmidt, Tobias; Neumuth, Thomas; Besting, Andreas; Stegemann, Dominik; Portheine, Frank; Herre, Heinrich

    2017-09-06

    Medical personnel in hospitals often works under great physical and mental strain. In medical decision-making, errors can never be completely ruled out. Several studies have shown that between 50 and 60% of adverse events could have been avoided through better organization, more attention or more effective security procedures. Critical situations especially arise during interdisciplinary collaboration and the use of complex medical technology, for example during surgical interventions and in perioperative settings (the period of time before, during and after surgical intervention). In this paper, we present an ontology and an ontology-based software system, which can identify risks across medical processes and supports the avoidance of errors in particular in the perioperative setting. We developed a practicable definition of the risk notion, which is easily understandable by the medical staff and is usable for the software tools. Based on this definition, we developed a Risk Identification Ontology (RIO) and used it for the specification and the identification of perioperative risks. An agent system was developed, which gathers risk-relevant data during the whole perioperative treatment process from various sources and provides it for risk identification and analysis in a centralized fashion. The results of such an analysis are provided to the medical personnel in form of context-sensitive hints and alerts. For the identification of the ontologically specified risks, we developed an ontology-based software module, called Ontology-based Risk Detector (OntoRiDe). About 20 risks relating to cochlear implantation (CI) have already been implemented. Comprehensive testing has indicated the correctness of the data acquisition, risk identification and analysis components, as well as the web-based visualization of results.

  20. Cyber Risk Management for Critical Infrastructure: A Risk Analysis Model and Three Case Studies.

    Science.gov (United States)

    Paté-Cornell, M-Elisabeth; Kuypers, Marshall; Smith, Matthew; Keller, Philip

    2018-02-01

    Managing cyber security in an organization involves allocating the protection budget across a spectrum of possible options. This requires assessing the benefits and the costs of these options. The risk analyses presented here are statistical when relevant data are available, and system-based for high-consequence events that have not happened yet. This article presents, first, a general probabilistic risk analysis framework for cyber security in an organization to be specified. It then describes three examples of forward-looking analyses motivated by recent cyber attacks. The first one is the statistical analysis of an actual database, extended at the upper end of the loss distribution by a Bayesian analysis of possible, high-consequence attack scenarios that may happen in the future. The second is a systems analysis of cyber risks for a smart, connected electric grid, showing that there is an optimal level of connectivity. The third is an analysis of sequential decisions to upgrade the software of an existing cyber security system or to adopt a new one to stay ahead of adversaries trying to find their way in. The results are distributions of losses to cyber attacks, with and without some considered countermeasures in support of risk management decisions based both on past data and anticipated incidents. © 2017 Society for Risk Analysis.

  1. Econometric analysis of the R and D performance in the national hydrogen energy technology development for measuring relative efficiency: The fuzzy AHP/DEA integrated model approach

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seong Kon; Kim, Jong Wook [Energy Policy Research Center, Korea Institute of Energy Research, 71-2, Jang-dong, Yuseong-gu, Daejeon 305-343 (Korea); Mogi, Gento [Department of Technology management for innovation, Graduate School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Lee, Sang Kon [PNU-IFAM Joint Research Center, Pusan National University, 30 Jangjeon-Dong, Kumjeong-Gu, Busan 609-735 (Korea); Hui, K.S. [Department of Manufacturing Engineering and Engineering Management, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong (China)

    2010-03-15

    Hydrogen energy technology can be one of the best key players related to the sector of the United Nations Framework Convention on Climate Change (UNFCCC) and the hydrogen economy. Comparing to other technologies, hydrogen energy technology is more environmentally sound and friendly energy technology and has great potential as a future dominant energy carrier. Advanced nations including Korea have been focusing on the development of hydrogen energy technology R and D for the sustainable development and low carbon green society. In this paper, we applied the integrated fuzzy analytic hierarchy process (Fuzzy AHP) and the data envelopment analysis (DEA) for measuring the relative efficiency of the R and D performance in the national hydrogen energy technology development. On the first stage, the fuzzy AHP effectively reflects the vagueness of human thought. On the second stage, the DEA approach measures the relative efficiency of the national R and D performance in the sector of hydrogen energy technology development with economic viewpoints. The efficiency score can be the fundamental data for policymakers for the well focused R and D planning. (author)

  2. Molecular structure and vibrational spectroscopic analysis of an antiplatelet drug; clopidogrel hydrogen sulphate (form 2) - A combined experimental and quantum chemical approach

    Science.gov (United States)

    Srivastava, Anubha; Mishra, Soni; Tandon, Poonam; Patel, Sarasvatkumar; Ayala, A. P.; Bansal, A. K.; Siesler, H. W.

    2010-02-01

    Clopidogrel hydrogen sulphate which belongs to a class of medicine called antiplatelet drugs. Chemically it is methyl (+)-(S)-α-(2-chlorophenyl)-4,5,6,7-tetrahydrothieno [3,2- c] pyridine-5-acetate hydrogen sulphate having the empirical formula C 16H 17ClNO 2S.HSO 4 and molecular mass 321.82 g/mol. The present study is confined to vibrational spectroscopy of the polymorph identified as form 2 of the clopidogrel hydrogen sulphate. The vibrational analysis of clopidogrel hydrogen sulphate salt (form 2) considering separately the two counterions has been performed. We also report a theoretical and experimental study of the molecular conformation and vibrational dynamics of the independent moieties of the clopidogrel hydrogen sulphate salt. The equilibrium geometry, harmonic vibrational frequencies, infrared intensities and activities of Raman scattering were calculated by ab initio Hartree-Fock and density functional theory employing B3LYP with complete relaxation in the potential energy surface using 6-311++G(d,p) basis set. The calculated wavenumbers after a proper scaling show a very good agreement with the observed values. A complete vibrational assignment is provided for the observed Raman and infrared spectra of clopidogrel hydrogen sulphate form 2.

  3. Hydrogen Production for Refuelling Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hulteberg, Christian; Aagesen, Diane (Intelligent Energy, Long Beach, CA (United States))

    2009-08-15

    The aim of this work is to support the development of a high-profile demonstration of hydrogen generation technologies in a Swedish context. The overall objective of the demonstration is to deploy a reforming based hydrogen refilling station along the Swedish west coast; intermediate to the Malmoe refuelling station and planned stations in Goeteborg. In this way, the Norwegian hydrogen highway will be extended through the south of Sweden and down into Denmark. The aim of the project's first phase, where this constitutes the final report, was to demonstrate the ability to operate the IE reforming system on the E.On/SGC site-specific fuel. During the project, a preliminary system design has been developed, based on IE's proprietary reformer. The system has been operated at pressure, to ensure a stable operation of the downstream PSA; which has been operated without problems and with the expected hydrogen purity and recovery. The safe operation of the proposed and tested system was first evaluated in a preliminary risk assessment, as well as a full HazOp analysis. A thorough economic modelling has been performed on the viability of owning and operating this kind of hydrogen generation equipment. The evaluation has been performed from an on-site operation of such a unit in a refuelling context. The general conclusion from this modelling is that there are several parameters that influence the potential of an investment in a Hestia hydrogen generator. The sales price of the hydrogen is one of the major drivers of profitability. Another important factor is the throughput of the unit, more important than efficiency and utilization. Varying all of the parameters simultaneously introduce larger variations in the NPV, but 60% of the simulations are in the USD 90 000 to USD 180 000 interval. The chosen intervals for the parameters were: Hydrogen Sales Price (USD 5 - USD 7 per kg); Investment Cost (USD 70 000 - USD 130 000 per unit); Throughput (20 - 30 kg

  4. Use Of Risk Analysis Fremeworks In Urban Flood Assessments

    DEFF Research Database (Denmark)

    Arnbjerg-Nielsen, Karsten; Madsen, Henrik

    , primarily insurance companies and mortgage providers, but also politicians and media are highly interested. Presently two very different approaches are being followed in both research and practice. One is the introduction of risk analysis and risk management tools to provide professionals and politicians...... in extreme precipitation has been observed, corresponding to an increase of design levels of at least 30 %. Analysis of climate change model output has given clear evidence, that further increases in extreme precipitation must be expected in the future due to anthropogenic emissions of greenhouse gasses...... with better decision support tools. Some of the developments are risk frameworks that encompass economic and/or ethic evaluation of climate change adaptation options and improved risk management. This line of development is based on a societal-based evaluation of maximizing the outcome for society...

  5. ANALYSIS METHODS OF BANKRUPTCY RISK IN ROMANIAN ENERGY MINING INDUSTRY

    Directory of Open Access Journals (Sweden)

    CORICI MARIAN CATALIN

    2016-12-01

    Full Text Available The study is an analysis of bankruptcy risk and assessing the economic performance of the entity in charge of energy mining industry from southwest region. The scientific activity assesses the risk of bankruptcy using score’s method and some indicators witch reflecting the results obtained and elements from organization balance sheet involved in mining and energy which contributes to the stability of the national energy system. Analysis undertaken is focused on the application of the business organization models that allow a comprehensive assessment of the risk of bankruptcy and be an instrument of its forecast. In this study will be highlighted developments bankruptcy risk within the organization through the Altman model and Conan-Holder model in order to show a versatile image on the organization's ability to ensure business continuity

  6. Conformational Analysis of Proteins in Highly Concentrated Solutions by Dialysis-Coupled Hydrogen/Deuterium Exchange Mass Spectrometry

    DEFF Research Database (Denmark)

    Houde, Damian; Esmail Nazari, Zeinab; Bou-Assaf, George M

    2016-01-01

    When highly concentrated, an antibody solution can exhibit unusual behaviors, which can lead to unwanted properties, such as increased levels of protein aggregation and unusually high viscosity. Molecular modeling, along with many indirect biophysical measurements, has suggested that the cause...... for these phenomena can be due to short range electrostatic and/or hydrophobic protein-protein interactions. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) is a useful tool for investigating protein conformation, dynamics, and interactions. However, "traditional" continuous dilution labeling HDX......-MS experiments have limited utility for the direct analysis of solutions with high concentrations of protein. Here, we present a dialysis-based HDX-MS (di-HDX-MS) method as an alternative HDX-MS labeling format, which takes advantage of passive dialysis rather than the classic dilution workflow. We applied...

  7. Layer of protection analysis for reactive chemical risk assessment.

    Science.gov (United States)

    Wei, Chunyang; Rogers, William J; Mannan, M Sam

    2008-11-15

    Reactive chemical hazards have been a significant concern for the chemical process industries (CPI). Without sufficient control and mitigation of chemical reaction hazards, reactive incidents have led to severe consequences, such as release of flammable and toxic materials, fires and explosions, and threats to human lives, properties, and the environment. Consequence of reactive hazards can be well understood through calorimetric testing and computational techniques. However, risks of incidents caused by reactive chemicals have not been well addressed due partly to sparse failure frequency data. In this paper, the semi-quantitative layer of protection analysis (LOPA) approach is used to estimate reactive chemical risk, and the probabilities or frequencies of failure scenarios are addressed. Using LOPA, reactive risks can be evaluated with respect to predefined criteria, and the effectiveness of risk reduction measures can be assessed. The hydroxylamine (HA) production system is employed as a case study to demonstrate the application of LOPA to reactive chemical risk assessment.

  8. Surplus analysis of Sparre Andersen insurance risk processes

    CERN Document Server

    Willmot, Gordon E

    2017-01-01

    This carefully written monograph covers the Sparre Andersen process in an actuarial context using the renewal process as the model for claim counts. A unified reference on Sparre Andersen (renewal risk) processes is included, often missing from existing literature. The authors explore recent results and analyse various risk theoretic quantities associated with the event of ruin, including the time of ruin and the deficit of ruin. Particular attention is given to the explicit identification of defective renewal equation components, which are needed to analyse various risk theoretic quantities and are also relevant in other subject areas of applied probability such as dams and storage processes, as well as queuing theory. Aimed at researchers interested in risk/ruin theory and related areas, this work will also appeal to graduate students in classical and modern risk theory and Gerber-Shiu analysis.

  9. Risk factor analysis of equine strongyle resistance to anthelmintics

    Directory of Open Access Journals (Sweden)

    G. Sallé

    2017-12-01

    Full Text Available Intestinal strongyles are the most problematic endoparasites of equids as a result of their wide distribution and the spread of resistant isolates throughout the world. While abundant literature can be found on the extent of anthelmintic resistance across continents, empirical knowledge about associated risk factors is missing. This study brought together results from anthelmintic efficacy testing and risk factor analysis to provide evidence-based guidelines in the field. It involved 688 horses from 39 French horse farms and riding schools to both estimate Faecal Egg Count Reduction (FECR after anthelmintic treatment and to interview farm and riding school managers about their practices. Risk factors associated with reduced anthelmintic efficacy in equine strongyles were estimated across drugs using a marginal modelling approach. Results demonstrated ivermectin efficacy (96.3% ± 14.5% FECR, the inefficacy of fenbendazole (42.8% ± 33.4% FECR and an intermediate profile for pyrantel (90.3% ± 19.6% FECR. Risk factor analysis provided support to advocate for FEC-based treatment regimens combined with individual anthelmintic dosage and the enforcement of tighter biosecurity around horse introduction. The combination of these measures resulted in a decreased risk of drug resistance (relative risk of 0.57, p = 0.02. Premises falling under this typology also relied more on their veterinarians suggesting practitionners play an important role in the sustainability of anthelmintic usage. Similarly, drug resistance risk was halved in premises with frequent pasture rotation and with stocking rate below five horses/ha (relative risk of 0.53, p < 0.01. This is the first empirical risk factor analysis for anthelmintic resistance in equids. Our findings should guide the implementation of more sustained strongyle management in the field. Keywords: Horse, Nematode, Anthelmintic resistance, Strongyle, Cyathostomin

  10. Risk portofolio management under Zipf analysis based strategies

    OpenAIRE

    M. Ausloos Ph. Bronlet

    2005-01-01

    A so called Zipf analysis portofolio management technique is introduced in order to comprehend the risk and returns. Two portofoios are built each from a well known financial index. The portofolio management is based on two approaches: one called the "equally weighted portofolio", the other the "confidence parametrized portofolio". A discussion of the (yearly) expected return, variance, Sharpe ratio and $\\beta$ follows. Optimization levels of high returns or low risks are found.

  11. RISK ANALYSIS ON MEASURE OF FINANCIAL INDICATORS OF CONSTRUCTION ENTERPRISES

    OpenAIRE

    Lima, André Soares de Menezes; Lima, Nilton Cesar; Souza, Gustavo Henrique Silva de; Martins, Vidigal Fernandes

    2016-01-01

    The construction companies that choose to participate in the execution of public works are exposed to various risks while performing their activities. Many of these works are paralyzed due to the fact that companies cannot afford the high costs of their implementation. Given this fact, this study sought to identify, through the analysis of the financial statements of the heavy construction companies listed on Bovespa, the risks to which these contractors are exposed. It was possible to note t...

  12. Economic Analysis of Hydrogen Energy Station Concepts: Are "H 2E-Stations" a Key Link to a Hydrogen Fuel Cell Vehicle Infrastructure?

    OpenAIRE

    Lipman, Timothy E.; Edwards, Jennifer L.; Kammen, Daniel M.

    2002-01-01

    Fuel cell vehicles (FCVs) powered directly with hydrogen (H2) will need access to a H2 refueling infrastruture. For this reason, most direct-H2 FCVs introduced prior to 2008-2010 are likely to be placed in fleets where they can be centrally refueled. However, access to additional refueling sites would increase the usefulness of these early FCVs, and once FCV commercialization spreads to the general public, consumers will require at least a minimal H2 refueling infrastructure in order to make ...

  13. Contributions to risk informed decision-making. Operational risk analysis in the oil and gas industry

    Energy Technology Data Exchange (ETDEWEB)

    Roeed, Willy

    2006-08-15

    This thesis addresses the use of risk analyses to support decision-making, to find the balance between different concerns, such as for example safety of personnel and operational costs, i.e. economic values. The focus is on the offshore oil and gas industry, but many of the discussions and conclusions are general and could also be applied to other industries. The thesis applies an understanding of risk being the combination of the two basic dimensions (a) possible consequences (outcomes) and (b) associated uncertainties. This risk concept is general, and risk analyses can be used to provide decision-making support to all kinds of decision problems. However, our main focus is on risk analyses in the operational phase, so-called operational risk analyses, and in particular evaluation of safety barrier performance, for the protection of personnel, environment and assets. Hence, the main focus in this thesis is upon risks in terms of hazardous events. The challenges in the operational phase differ from the planning phase, and many risk analyses carried out today do not reflect installation-specific information obtained in the operational phase to the extent that is wanted. There is a need for more suitable risk analysis tools, and the thesis gives some contributions to development of such tools

  14. State of the art in benefit-risk analysis: introduction.

    Science.gov (United States)

    Verhagen, H; Tijhuis, M J; Gunnlaugsdóttir, H; Kalogeras, N; Leino, O; Luteijn, J M; Magnússon, S H; Odekerken, G; Pohjola, M V; Tuomisto, J T; Ueland, Ø; White, B C; Holm, F

    2012-01-01

    Risk-taking is normal in everyday life if there are associated (perceived) benefits. Benefit-Risk Analysis (BRA) compares the risk of a situation to its related benefits and addresses the acceptability of the risk. Over the past years BRA in relation to food and food ingredients has gained attention. Food, and even the same food ingredient, may confer both beneficial and adverse effects. Measures directed at food safety may lead to suboptimal or insufficient levels of ingredients from a benefit perspective. In BRA, benefits and risks of food (ingredients) are assessed in one go and may conditionally be expressed into one currency. This allows the comparison of adverse and beneficial effects to be qualitative and quantitative. A BRA should help policy-makers to make more informed and balanced benefit-risk management decisions. Not allowing food benefits to occur in order to guarantee food safety is a risk management decision much the same as accepting some risk in order to achieve more benefits. BRA in food and nutrition is making progress, but difficulties remain. The field may benefit from looking across its borders to learn from other research areas. The BEPRARIBEAN project (Best Practices for Risk-Benefit Analysis: experience from out of food into food; http://en.opasnet.org/w/Bepraribean) aims to do so, by working together with Medicines, Food Microbiology, Environmental Health, Economics & Marketing-Finance and Consumer Perception. All perspectives are reviewed and subsequently integrated to identify opportunities for further development of BRA for food and food ingredients. Interesting issues that emerge are the varying degrees of risk that are deemed acceptable within the areas and the trend towards more open and participatory BRA processes. A set of 6 'state of the art' papers covering the above areas and a paper integrating the separate (re)views are published in this volume. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Hypertension and Risk of Cataract: A Meta-Analysis

    Science.gov (United States)

    Yu, Xiaoning; Lyu, Danni; Dong, Xinran; He, Jiliang; Yao, Ke

    2014-01-01

    Background Cataract is the major cause of blindness across the world. Many epidemiologic studies indicated that hypertension might play an important role in the development of cataract, while others not. We therefore conducted this meta-analysis to determine the relationship between risk of cataract and hypertension. Methods Retrieved studies on the association of hypertension with cataract risk were collected from PubMed, Web of Science and the Cochrane Library during June 2014 and were included into the final analysis according to the definite inclusion criteria. Odds ratio (OR) or risk ratio (RR) were pooled with 95% confidence interval (CI) to evaluate the relationship between hypertension and cataract risk. Subgroup analyses were carried out on the basis of cataract type, race and whether studies were adjusted for main components of metabolic syndrome (MS). Results The final meta-analysis included 25 studies (9 cohort, 5 case-control and 11 cross-sectional) from 23 articles. The pooled results showed that cataract risk in populations with hypertension significantly increased among cohort studies (RR 1.08; 95% CI: 1.05–1.12) and case-control or cross-sectional studies (OR 1.28; 95% CI: 1.12–1.45). This association was proved to be true among both Mongolians and Caucasians, and the significance was not altered by the adjustment of main components of MS. Subgroup analysis on cataract types indicated that an increased incidence of posterior subcapsular cataract (PSC) resulted among cohort studies (RR 1.22; 95% CI: 1.03–1.46) and cross-sectional/case-control studies (OR 1.23; 95% CI: 1.09–1.39). No association of hypertension with risk of nuclear cataract was found. Conclusions The present meta-analysis suggests that hypertension increases the risk of cataract, especially PSC. Further efforts should be made to explore the potential biological mechanisms. PMID:25474403

  16. Comparative proteomic analysis of differentially expressed proteins induced by hydrogen sulfide in Spinacia oleracea leaves.

    Science.gov (United States)

    Chen, Juan; Liu, Ting-Wu; Hu, Wen-Jun; Simon, Martin; Wang, Wen-Hua; Chen, Juan; Liu, Xiang; Zheng, Hai-Lei

    2014-01-01

    Hydrogen sulfide (H2S), as a potential gaseous messenger molecule, has been suggested to play important roles in a wide range of physiological processes in plants. The aim of present study was to investigate which set of proteins is involved in H2S-regulated metabolism or signaling pathways. Spinacia oleracea seedlings were treated with 100 µM NaHS, a donor of H2S. Changes in protein expression profiles were analyzed by 2-D gel electrophoresis coupled with MALDI-TOF MS. Over 1000 protein spots were reproducibly resolved, of which the abundance of 92 spots was changed by at least 2-fold (sixty-five were up-regulated, whereas 27 were down-regulated). These proteins were functionally divided into 9 groups, including energy production and photosynthesis, cell rescue, development and cell defense, substance metabolism, protein synthesis and folding, cellular signal transduction. Further, we found that these proteins were mainly localized in cell wall, plasma membrane, chloroplast, mitochondria, nucleus, peroxisome and cytosol. Our results demonstrate that H2S is involved in various cellular and physiological activities and has a distinct influence on photosynthesis, cell defense and cellular signal transduction in S. oleracea leaves. These findings provide new insights into proteomic responses in plants under physiological levels of H2S.

  17. Comparative proteomic analysis of differentially expressed proteins induced by hydrogen sulfide in Spinacia oleracea leaves.

    Directory of Open Access Journals (Sweden)

    Juan Chen

    Full Text Available Hydrogen sulfide (H2S, as a potential gaseous messenger molecule, has been suggested to play important roles in a wide range of physiological processes in plants. The aim of present study was to investigate which set of proteins is involved in H2S-regulated metabolism or signaling pathways. Spinacia oleracea seedlings were treated with 100 µM NaHS, a donor of H2S. Changes in protein expression profiles were analyzed by 2-D gel electrophoresis coupled with MALDI-TOF MS. Over 1000 protein spots were reproducibly resolved, of which the abundance of 92 spots was changed by at least 2-fold (sixty-five were up-regulated, whereas 27 were down-regulated. These proteins were functionally divided into 9 groups, including energy production and photosynthesis, cell rescue, development and cell defense, substance metabolism, protein synthesis and folding, cellular signal transduction. Further, we found that these proteins were mainly localized in cell wall, plasma membrane, chloroplast, mitochondria, nucleus, peroxisome and cytosol. Our results demonstrate that H2S is involved in various cellular and physiological activities and has a distinct influence on photosynthesis, cell defense and cellular signal transduction in S. oleracea leaves. These findings provide new insights into proteomic responses in plants under physiological levels of H2S.

  18. A new method for removal of hydrogen peroxide interference in the analysis of chemical oxygen demand.

    Science.gov (United States)

    Wu, Tingting; Englehardt, James D

    2012-02-21

    Many advanced oxidation processes involve addition of hydrogen peroxide (H(2)O(2)) with the aim of generating hydroxyl radicals to oxidize organic contaminants in water. However, chemical oxygen demand, a common measure of gross residual organic contamination, is subject to interference from residual H(2)O(2) in the treated water. A new method, involving catalytic decomposition of H(2)O(2) with addition of heat and sodium carbonate (Na(2)CO(3)), is proposed in this work to address this problem. The method is demonstrated experimentally, and modeled kinetically. Results for 5 mM H(2)O(2) in deionized (DI) water included reduction to below the COD detection limit after 60 min heating (90(◦)C) with addition of 20 g/L Na(2)CO(3) concentrated solution, whereas 900 min were required in treated municipal wastewater. An approximate second order rate constant of 11.331 M(-1)·min(-1) at Na(2)CO(3) dosage of 20 g/L was found for the tested wastewater. However, kinetic modeling indicated a two-step reaction mechanism, with formation of peroxocarbonate (CO(4)(2-)) and ultimate decomposition to H(2)O and O(2) in pure H(2)O(2) solution. A similar mechanism is apparent in wastewater at high catalyst concentrations, whereas at low Na(2)CO(3) addition rates, the catalytic effects of other constituents appear important.

  19. Analysis of turbulent free jet hydrogen-air diffusion flames with finite chemical reaction rates

    Science.gov (United States)

    Sislian, J. P.

    1978-01-01

    The nonequilibrium flow field resulting from the turbulent mixing and combustion of a supersonic axisymmetric hydrogen jet in a supersonic parallel coflowing air stream is analyzed. Effective turbulent transport properties are determined using the (K-epsilon) model. The finite-rate chemistry model considers eight reactions between six chemical species, H, O, H2O, OH, O2, and H2. The governing set of nonlinear partial differential equations is solved by an implicit finite-difference procedure. Radial distributions are obtained at two downstream locations of variables such as turbulent kinetic energy, turbulent dissipation rate, turbulent scale length, and viscosity. The results show that these variables attain peak values at the axis of symmetry. Computed distributions of velocity, temperature, and mass fraction are also given. A direct analytical approach to account for the effect of species concentration fluctuations on the mean production rate of species (the phenomenon of unmixedness) is also presented. However, the use of the method does not seem justified in view of the excessive computer time required to solve the resulting system of equations.

  20. An ion species model for positive ion sources - part II analysis of hydrogen isotope effects

    CERN Document Server

    Surrey, E

    2014-01-01

    A one dimensional model of the magnetic multipole volume plasma source has been developed for application to intense ion/neutral atom beam injectors. The model uses plasma transport coefficients for particle and energy flow to create a detailed description of the plasma parameters along an axis parallel to that of the extracted beam. In this paper the isotopic modelling of positive hydrogenic ions is considered and compared with experimental data from the neutral beam injectors of the Joint European Torus. The use of the code to gain insights into the processes contributing to the ratios of the ionic species is demonstrated and the conclusion is drawn that 75% of the atomic ion species arises from ionization of dissociated molecules and 25% from dissociation of the molecular ions. However whilst the former process is independent of the filter field, the latter is sensitive to the change in distribution of fast and thermal electrons produced by the magnetic filter field and an optimum combination of field stre...

  1. Analysis of multiple scattering contributions in electron-impact ionization of molecular hydrogen

    Science.gov (United States)

    Ren, Xueguang; Hossen, Khokon; Wang, Enliang; Pindzola, M. S.; Dorn, Alexander; Colgan, James

    2017-10-01

    We report a combined experimental and theoretical study on the low-energy (E 0 = 31.5 eV) electron-impact ionization of molecular hydrogen (H2). Triple differential cross sections are measured for a range of fixed emission angles of one outgoing electron between {θ }1=-70^\\circ and -130° covering the full 4π solid angle of the second electron. The energy sharing of the outgoing electrons varies from symmetric ({E}1={E}2=8 eV) to highly asymmetric (E 1 = 1 eV and E 2 = 15 eV). In addition to the binary and recoil lobes, a structure is observed perpendicular to the incoming beam direction which is due to multiple scattering of the projectile inside the molecular potential. The absolutely normalized experimental cross sections are compared with results from the time-dependent close-coupling (TDCC) calculations. Molecular alignment dependent TDCC results demonstrate that these structures are only present if the molecule axis is lying in the scattering plane.

  2. Risk Analysis and Decision Making FY 2013 Milestone Report

    Energy Technology Data Exchange (ETDEWEB)

    Engel, David W.; Dalton, Angela C.; Dale, Crystal; Jones, Edward; Thompson, J.

    2013-06-01

    Risk analysis and decision making is one of the critical objectives of CCSI, which seeks to use information from science-based models with quantified uncertainty to inform decision makers who are making large capital investments. The goal of this task is to develop tools and capabilities to facilitate the development of risk models tailored for carbon capture technologies, quantify the uncertainty of model predictions, and estimate the technical and financial risks associated with the system. This effort aims to reduce costs by identifying smarter demonstrations, which could accelerate development and deployment of the technology by several years.

  3. Is adaptation or transformation needed? Active nanomaterials and risk analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kuzma, Jennifer, E-mail: jkuzma@ncsu.edu [North Carolina State University, School of Public and International Affairs and Genetic Engineering and Society Center (United States); Roberts, John Patrick [North Carolina State University, School of Public and International Affairs (United States)

    2016-07-15

    Nanotechnology has been a key area of funding and policy for the United States and globally for the past two decades. Since nanotechnology research and development became a focus and nanoproducts began to permeate the market, scholars and scientists have been concerned about how to assess the risks that they may pose to human health and the environment. The newest generation of nanomaterials includes biomolecules that can respond to and influence their environments, and there is a need to explore whether and how existing risk-analysis frameworks are challenged by such novelty. To fill this niche, we used a modified approach of upstream oversight assessment (UOA), a subset of anticipatory governance. We first selected case studies of “active nanomaterials,” that are early in research and development and designed for use in multiple sectors, and then considered them under several, key risk-analysis frameworks. We found two ways in which the cases challenge the frameworks. The first category relates to how to assess risk under a narrow framing of the term (direct health and environmental harm), and the second involves the definition of what constitutes a “risk” worthy of assessment and consideration in decision making. In light of these challenges, we propose some changes for risk analysis in the face of active nanostructures in order to improve risk governance.

  4. Risk Analysis Methodology for Kistler's K-1 Reusable Launch Vehicle

    Science.gov (United States)

    Birkeland, Paul W.

    2002-01-01

    Missile risk analysis methodologies were originally developed in the 1940s as the military experimented with intercontinental ballistic missile (ICBM) technology. As the range of these missiles increased, it became apparent that some means of assessing the risk posed to neighboring populations was necessary to gauge the relative safety of a given test. There were many unknowns at the time, and technology was unpredictable at best. Risk analysis itself was in its infancy. Uncertainties in technology and methodology led to an ongoing bias toward conservative assumptions to adequately bound the problem. This methodology ultimately became the Casualty Expectation Analysis that is used to license Expendable Launch Vehicles (ELVs). A different risk analysis approach was adopted by the commercial aviation industry in the 1950s. At the time, commercial aviation technology was more firmly in hand than ICBM technology. Consequently commercial aviation risk analysis focused more closely on the hardware characteristics. Over the years, this approach has enabled the advantages of technological and safety advances in commercial aviation hardware to manifest themselves in greater capabilities and opportunities. The Boeing 777, for example, received approval for trans-oceanic operations "out of the box," where all previous aircraft were required, at the very least, to demonstrate operations over thousands of hours before being granted such approval. This "out of the box" approval is likely to become standard for all subsequent designs. In short, the commercial aircraft approach to risk analysis created a more flexible environment for industry evolution and growth. In contrast, the continued use of the Casualty Expectation Analysis by the launch industry is likely to hinder industry maturation. It likely will cause any safety and reliability gains incorporated into RLV design to be masked by the conservative assumptions made to "bound the problem." Consequently, for the launch

  5. Analysis of interactions among barriers in project risk management

    Science.gov (United States)

    Dandage, Rahul V.; Mantha, Shankar S.; Rane, Santosh B.; Bhoola, Vanita

    2017-06-01

    In the context of the scope, time, cost, and quality constraints, failure is not uncommon in project management. While small projects have 70% chances of success, large projects virtually have no chance of meeting the quadruple constraints. While there is no dearth of research on project risk management, the manifestation of barriers to project risk management is a less dwelt topic. The success of project management is oftentimes based on the understanding of barriers to effective risk management, application of appropriate risk management methodology, proactive leadership to avoid barriers, workers' attitude, adequate resources, organizational culture, and involvement of top management. This paper represents various risk categories and barriers to risk management in domestic and international projects through literature survey and feedback from project professionals. After analysing the various modelling methods used in project risk management literature, interpretive structural modelling (ISM) and MICMAC analysis have been used to analyse interactions among the barriers and prioritize them. The analysis indicates that lack of top management support, lack of formal training, and lack of addressing cultural differences are the high priority barriers, among many others.

  6. Gambler Risk Perception: A Mental Model and Grounded Theory Analysis.

    Science.gov (United States)

    Spurrier, Michael; Blaszczynski, Alexander; Rhodes, Paul

    2015-09-01

    Few studies have investigated how gamblers perceive risk or the role of risk perception in disordered gambling. The purpose of the current study therefore was to obtain data on lay gamblers' beliefs on these variables and their effects on decision-making, behaviour, and disordered gambling aetiology. Fifteen regular lay gamblers (non-problem/low risk, moderate risk and problem gamblers) completed a semi-structured interview following mental models and grounded theory methodologies. Gambler interview data was compared to an expert 'map' of risk-perception, to identify comparative gaps or differences associated with harmful or safe gambling. Systematic overlapping processes of data gathering and analysis were used to iteratively extend, saturate, test for exception, and verify concepts and themes emerging from the data. The preliminary findings suggested that gambler accounts supported the presence of expert conceptual constructs, and to some degree the role of risk perception in protecting against or increasing vulnerability to harm and disordered gambling. Gambler accounts of causality, meaning, motivation, and strategy were highly idiosyncratic, and often contained content inconsistent with measures of disordered gambling. Disordered gambling appears heavily influenced by relative underestimation of risk and overvaluation of gambling, based on explicit and implicit analysis, and deliberate, innate, contextual, and learned processing evaluations and biases.

  7. Hydrogen Bibliography

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-01

    The Hydrogen Bibliography is a compilation of research reports that are the result of research funded over the last fifteen years. In addition, other documents have been added. All cited reports are contained in the National Renewable Energy Laboratory (NREL) Hydrogen Program Library.

  8. Hydrogen exchange

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Rand, Kasper Dyrberg

    2016-01-01

    Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

  9. An numerical analysis of high-temperature helium reactor power plant for co-production of hydrogen and electricity

    Science.gov (United States)

    Dudek, M.; Podsadna, J.; Jaszczur, M.

    2016-09-01

    In the present work, the feasibility of using a high temperature gas cooled nuclear reactor (HTR) for electricity generation and hydrogen production are analysed. The HTR is combined with a steam and a gas turbine, as well as with the system for heat delivery for medium temperature hydrogen production. Industrial-scale hydrogen production using copper-chlorine (Cu-Cl) thermochemical cycle is considered and compared with high temperature electrolysis. Presented cycle shows a very promising route for continuous, efficient, large-scale and environmentally benign hydrogen production without CO2 emissions. The results show that the integration of a high temperature helium reactor, with a combined cycle for electric power generation and hydrogen production, may reach very high efficiency and could possibly lead to a significant decrease of hydrogen production costs.

  10. Towards quantitative SERS detection of hydrogen cyanide at ppb level for human breath analysis

    Directory of Open Access Journals (Sweden)

    Rikke Kragh Lauridsen

    2015-09-01

    Full Text Available Lung infections with Pseudomonas aeruginosa (PA is the most common cause of morbidity and mortality in cystic fibrosis (CF patients. Due to its ready adaptation to the dehydrated mucosa of CF airways, PA infections tend to become chronic, eventually killing the patient. Hydrogen cyanide (HCN at ppb level has been reported to be a PA biomarker. For early PA detection in CF children not yet chronically lung infected a non-invasive Surface-Enhanced Raman Spectroscopy (SERS-based breath nanosensor is being developed. The triple bond between C and N in cyanide, with its characteristic band at ∼2133 cm−1, is an excellent case for the SERS-based detection due to the infrequent occurrence of triple bonds in nature. For demonstration of direct HCN detection in the gas phase, a gold-coated silicon nanopillar substrate was exposed to 5 ppm HCN in N2. Results showed that HCN adsorbed on the SERS substrate can be consistently detected under different experimental conditions and up to 9 days after exposure. For detection of lower cyanide concentrations serial dilution experiments using potassium cyanide (KCN demonstrated cyanide quantification down to 1 μM in solution (corresponding to 18 ppb. Lower KCN concentrations of 10 and 100 nM (corresponding to 0.18 and 1.8 ppb produced SERS intensities that were relatively similar to the reference signal. Since HCN concentration in the breath of PA colonized CF children is reported to be ∼13.5 ppb, the detection of cyanide is within the required range.

  11. Irreversibility analysis of hydrogen separation schemes in thermochemical cycles. [Condensation, physical absorption, diffusion, physical adsorption, thermal adsorption, and electrochemical separation

    Energy Technology Data Exchange (ETDEWEB)

    Cox, K.E.

    1978-01-01

    Six processes have been evaluated as regards irreversibility generation for hydrogen separation from binary gas mixtures. The results are presented as a series of plots of separation efficiency against the mol fraction hydrogen in the feed gas. Three processes, condensation, physical absorption and electrochemical separation indicate increasing efficiency with hydrogen content. The other processes, physical and thermal adsorption, and diffusion show maxima in efficiency at a hydrogen content of 50 mol percent. Choice of separation process will also depend on such parameters as condition of feed, impurity content and capital investment. For thermochemical cycles, schemes based on low temperature heat availability are preferable to those requiring a work input.

  12. Experimental and theoretical analysis of asymmetric induction in heterogeneous catalysis: diastereoselective hydrogenation of chiral alpha-hydroxyketones over Pt catalyst.

    Science.gov (United States)

    Busygin, Igor; Taskinen, Antti; Nieminen, Ville; Toukoniitty, Esa; Stillger, Thomas; Leino, Reko; Murzin, Dmitry Yu

    2009-04-01

    Assessing the origin of asymmetric induction in heterogeneously catalyzed hydrogenation is a challenging task. In this work, hydrogenation of a chiral compound, (R)-1-hydroxy-1-phenyl-2-propanone [(R)-PAC], in toluene over cinchonidine modified and unmodified Pt/Al(2)O(3) was studied. To reveal the detailed reaction mechanism and the origin of stereoselectivity in the Pt-catalyzed hydrogenation of the CO double bond, the structures and energies of several adsorption modes of (R)-PAC as well as whole reaction paths for hydrogenation were investigated on Pt(111) by density functional theory (DFT). In agreement with experimental results, the theoretically obtained potential energy profiles for the studied hydrogenation mechanisms implied that (1R,2S)-1-phenyl-1,2-propanediol is formed in excess with respect to the other diastereomeric product diol, (1R,2R)-1-phenyl-1,2-propanediol. Generally, if the elementary hydrogen addition step was thermodynamically more favorable on one of the two diastereotopic faces, it was also kinetically preferred on the same face, and vice versa. Pairwise addition of hydrogen was the most energetically favorable mechanism. Adsorption and hydrogenation of other structurally similar chiral alpha-hydroxyketones, (R)-3-hydroxy-2-butanone and (R)-2-hydroxy-1-cyclohexanone, were also studied computationally on Pt(111). The results showed that cluster model DFT calculations can be used to assess (dia)stereoselectivity in metal-catalyzed hydrogenation of even such complex organic molecules as studied here.

  13. A Big Data Analysis Approach for Rail Failure Risk Assessment.

    Science.gov (United States)

    Jamshidi, Ali; Faghih-Roohi, Shahrzad; Hajizadeh, Siamak; Núñez, Alfredo; Babuska, Robert; Dollevoet, Rolf; Li, Zili; De Schutter, Bart

    2017-08-01

    Railway infrastructure monitoring is a vital task to ensure rail transportation safety. A rail failure could result in not only a considerable impact on train delays and maintenance costs, but also on safety of passengers. In this article, the aim is to assess the risk of a rail failure by analyzing a type of rail surface defect called squats that are detected automatically among the huge number of records from video cameras. We propose an image processing approach for automatic detection of squats, especially severe types that are prone to rail breaks. We measure the visual length of the squats and use them to model the failure risk. For the assessment of the rail failure risk, we estimate the probability of rail failure based on the growth of squats. Moreover, we perform severity and crack growth analyses to consider the impact of rail traffic loads on defects in three different growth scenarios. The failure risk estimations are provided for several samples of squats with different crack growth lengths on a busy rail track of the Dutch railway network. The results illustrate the practicality and efficiency of the proposed approach. © 2017 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.

  14. Risk analysis by FMEA as an element of analytical validation.

    Science.gov (United States)

    van Leeuwen, J F; Nauta, M J; de Kaste, D; Odekerken-Rombouts, Y M C F; Oldenhof, M T; Vredenbregt, M J; Barends, D M

    2009-12-05

    We subjected a Near-Infrared (NIR) analytical procedure used for screening drugs on authenticity to a Failure Mode and Effects Analysis (FMEA), including technical risks as well as risks related to human failure. An FMEA team broke down the NIR analytical method into process steps and identified possible failure modes for each step. Each failure mode was ranked on estimated frequency of occurrence (O), probability that the failure would remain undetected later in the process (D) and severity (S), each on a scale of 1-10. Human errors turned out to be the most common cause of failure modes. Failure risks were calculated by Risk Priority Numbers (RPNs)=O x D x S. Failure modes with the highest RPN scores were subjected to corrective actions and the FMEA was repeated, showing reductions in RPN scores and resulting in improvement indices up to 5.0. We recommend risk analysis as an addition to the usual analytical validation, as the FMEA enabled us to detect previously unidentified risks.

  15. Analysis of risk factors and risk assessment for ischemic stroke recurrence

    Directory of Open Access Journals (Sweden)

    Xiu-ying LONG

    2016-08-01

    Full Text Available Objective To screen the risk factors for recurrence of ischemic stroke and to assess the risk of recurrence. Methods Essen Stroke Risk Score (ESRS was used to evaluate the risk of recurrence in 176 patients with ischemic stroke (96 cases of first onset and 80 cases of recurrence. Univariate and multivariate stepwise Logistic regression analysis was used to screen risk factors for recurrence of ischemic stroke.  Results There were significant differences between first onset group and recurrence group on age, the proportion of > 75 years old, hypertension, diabetes, coronary heart disease, peripheral angiopathy, transient ischemic attack (TIA or ischemic stroke, drinking and ESRS score (P < 0.05, for all. First onset group included one case of ESRS 0 (1.04%, 8 cases of 1 (8.33%, 39 cases of 2 (40.63%, 44 cases of 3 (45.83%, 4 cases of 4 (4.17%. Recurrence group included 2 cases of ESRS 3 (2.50%, 20 cases of 4 (25% , 37 cases of 5 (46.25% , 18 cases of 6 (22.50% , 3 cases of 7 (3.75% . There was significant difference between 2 groups (Z = -11.376, P = 0.000. Logistic regression analysis showed ESRS > 3 score was independent risk factor for recurrence of ischemic stroke (OR = 31.324, 95%CI: 3.934-249.430; P = 0.001.  Conclusions ESRS > 3 score is the independent risk factor for recurrence of ischemic stroke. It is important to strengthen risk assessment of recurrence of ischemic stroke. To screen and control risk factors is the key to secondary prevention of ischemic stroke. DOI: 10.3969/j.issn.1672-6731.2016.07.011

  16. Fault tree analysis for integrated and probabilistic risk analysis of drinking water systems.

    Science.gov (United States)

    Lindhe, Andreas; Rosén, Lars; Norberg, Tommy; Bergstedt, Olof

    2009-04-01

    Drinking water systems are vulnerable and subject to a wide range of risks. To avoid sub-optimisation of risk-reduction options, risk analyses need to include the entire drinking water system, from source to tap. Such an integrated approach demands tools that are able to model interactions between different events. Fault tree analysis is a risk estimation tool with the ability to model interactions between events. Using fault tree analysis on an integrated level, a probabilistic risk analysis of a large drinking water system in Sweden was carried out. The primary aims of the study were: (1) to develop a method for integrated and probabilistic risk analysis of entire drinking water systems; and (2) to evaluate the applicability of Customer Minutes Lost (CML) as a measure of risk. The analysis included situations where no water is delivered to the consumer (quantity failure) and situations where water is delivered but does not comply with water quality standards (quality failure). Hard data as well as expert judgements were used to estimate probabilities of events and uncertainties in the estimates. The calculations were performed using Monte Carlo simulations. CML is shown to be a useful measure of risks associated with drinking water systems. The method presented provides information on risk levels, probabilities of failure, failure rates and downtimes of the system. This information is available for the entire system as well as its different sub-systems. Furthermore, the method enables comparison of the results with performance targets and acceptable levels of risk. The method thus facilitates integrated risk analysis and consequently helps decision-makers to minimise sub-optimisation of risk-reduction options.

  17. Hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Donath, E.

    1942-10-16

    This report mentioned that not very severe demands for purity were made on the hydrogen used in hydrogenation of coal or similar raw materials, because the catalysts were not very sensitive to poisoning. However, the hydrogenation plants tried to remove most impurities anyway by means of oil washes. The report included a table giving the amount of wash oil used up and the amount of hydrogen lost by dissolving into the wash oil used up and the amount of hydrogen lost by dissolving into the wash oil in order to remove 1% of various impurities from 1000 m/sup 3/ of the circulating gas. The amounts of wash oil used up were 1.1 m/sup 3/ for removing 1% nitrogen, 0.3 m/sup 3/ for 1% carbon monoxide, 0.03 m/sup 3/ for 1% methane. The amount of hydrogen lost was 28 m/sup 3/ for 1% nitrogen, 9 m/sup 3/ for 1% methane and ranged from 9 m/sup 3/ to 39 m/sup 3/ for 1% carbon monoxide and 1 m/sup 3/ to 41 m/sup 3/ for carbon dioxide depending on whether the removal was done in liquid phase or vapor phase and with or without reduction of the oxide to methane. Next the report listed and described the major processes used in German hydrogenation plants to produce hydrogen. Most of them produced water gas, which then had its carbon monoxide changed to carbon dioxide, and the carbon oxides washed out with water under pressure and copper hydroxide solution. The methods included the Winkler, Pintsch-Hillebrand, and Schmalfeldt-Wintershall processes, as well as roasting of coke in a rotating generator, splitting of gases formed during hydrogenation, and separation of cokery gas into its components by the Linde process.

  18. Photoelectrochemical hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Rocheleau, R.E.; Miller, E.; Misra, A. [Univ. of Hawaii, Honolulu, HI (United States)

    1996-10-01

    The large-scale production of hydrogen utilizing energy provided by a renewable source to split water is one of the most ambitious long-term goals of the U.S. Department of Energy`s Hydrogen Program. One promising option to meet this goal is direct photoelectrolysis in which light absorbed by semiconductor-based photoelectrodes produces electrical power internally to split water into hydrogen and oxygen. Under this program, direct solar-to-chemical conversion efficiencies as high as 7.8 % have been demonstrated using low-cost, amorphous-silicon-based photoelectrodes. Detailed loss analysis models indicate that solar-to-chemical conversion greater than 10% can be achieved with amorphous-silicon-based structures optimized for hydrogen production. In this report, the authors describe the continuing progress in the development of thin-film catalytic/protective coatings, results of outdoor testing, and efforts to develop high efficiency, stable prototype systems.

  19. Downside Risk analysis applied to the Hedge Funds universe

    Science.gov (United States)

    Perelló, Josep

    2007-09-01

    Hedge Funds are considered as one of the portfolio management sectors which shows a fastest growing for the past decade. An optimal Hedge Fund management requires an appropriate risk metrics. The classic CAPM theory and its Ratio Sharpe fail to capture some crucial aspects due to the strong non-Gaussian character of Hedge Funds statistics. A possible way out to this problem while keeping the CAPM simplicity is the so-called Downside Risk analysis. One important benefit lies in distinguishing between good and bad returns, that is: returns greater or lower than investor's goal. We revisit most popular Downside Risk indicators and provide new analytical results on them. We compute these measures by taking the Credit Suisse/Tremont Investable Hedge Fund Index Data and with the Gaussian case as a benchmark. In this way, an unusual transversal lecture of the existing Downside Risk measures is provided.

  20. Infectious complications in bullous pemphigoid: an analysis of risk factors.

    Science.gov (United States)

    Phoon, Yee Wei; Fook-Chong, Stephanie M C; Koh, Hong Yi; Thirumoorthy, Thamotharampillai; Pang, Shiu Ming; Lee, Haur Yueh

    2015-05-01

    Infections are common in bullous pemphigoid and contribute to significant mortality. We sought to define the spectrum of infectious complications and to identify associated risk factors in a bullous pemphigoid cohort. A retrospective cohort study conducted at an academic medical center. In all, 97 patients were included. Infectious complications occurred in 54 patients (56%) and the median duration from diagnosis to first episode of infection was 3 months. Bacteremia occurred in 14 patients (26%) and 26 of 30 deaths (87%) were attributable to infections. On univariate analysis, significant risk factors include low Karnofsky score (risk factors for infectious complications include functional impairment and the presence of dementia, which may allow for better risk stratification and individualized treatment of bullous pemphigoid. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  1. Analysis of coastal protection under rising flood risk

    Directory of Open Access Journals (Sweden)

    Megan J. Lickley

    2014-01-01

    Full Text Available Infrastructure located along the U.S. Atlantic and Gulf coasts is exposed to rising risk of flooding from sea level rise, increasing storm surge, and subsidence. In these circumstances coastal management commonly based on 100-year flood maps assuming current climatology is no longer adequate. A dynamic programming cost–benefit analysis is applied to the adaptation decision, illustrated by application to an energy facility in Galveston Bay. Projections of several global climate models provide inputs to estimates of the change in hurricane and storm surge activity as well as the increase in sea level. The projected rise in physical flood risk is combined with estimates of flood damage and protection costs in an analysis of the multi-period nature of adaptation choice. The result is a planning method, using dynamic programming, which is appropriate for investment and abandonment decisions under rising coastal risk.

  2. Cognitive and Motivational Biases in Decision and Risk Analysis.

    Science.gov (United States)

    Montibeller, Gilberto; von Winterfeldt, Detlof

    2015-07-01

    Behavioral decision research has demonstrated that judgments and decisions of ordinary people and experts are subject to numerous biases. Decision and risk analysis were designed to improve judgments and decisions and to overcome many of these biases. However, when eliciting model components and parameters from decisionmakers or experts, analysts often face the very biases they are trying to help overcome. When these inputs are biased they can seriously reduce the quality of the model and resulting analysis. Some of these biases are due to faulty cognitive processes; some are due to motivations for preferred analysis outcomes. This article identifies the cognitive and motivational biases that are relevant for decision and risk analysis because they can distort analysis inputs and are difficult to correct. We also review and provide guidance about the existing debiasing techniques to overcome these biases. In addition, we describe some biases that are less relevant because they can be corrected by using logic or decomposing the elicitation task. We conclude the article with an agenda for future research. © 2015 Society for Risk Analysis.

  3. Alcohol drinking and pancreatic cancer risk: a meta-analysis of the dose-risk relation.

    Science.gov (United States)

    Tramacere, Irene; Scotti, Lorenza; Jenab, Mazda; Bagnardi, Vincenzo; Bellocco, Rino; Rota, Matteo; Corrao, Giovanni; Bravi, Francesca; Boffetta, Paolo; La Vecchia, Carlo

    2010-03-15

    In order to provide a more precise quantification of the association between alcohol consumption and pancreatic cancer risk, we performed a meta-analysis of relevant dose-risk results. We conducted a PubMed search of all case-control (N=21) and cohort (N=11) studies published up to March 2009. We computed summary relative risk (RR) estimates using either fixed- or, in the presence of heterogeneity, random-effects models. The pooled RR was 0.92 (95% confidence interval, 95% CI, 0.86-0.97) for or = 3 drinks/day. The increased risk for heavy drinking was similar in women and men, but apparently stronger in cohort studies (RR=1.29), in studies with high quality index (RR=1.30), and did not appear to be explained by residual confounding by either history of pancreatitis or tobacco smoking. This meta-analysis provides strong evidence for the absence of a role of moderate drinking in pancreatic carcinogenesis, coupled to an increased risk for heavy alcohol drinking. Given the moderate increase in risk and the low prevalence of heavy drinkers in most populations, alcohol appears to be responsible only for a small fraction of all pancreatic cancers.

  4. Meta-analysis of modifiable risk factors for Alzheimer's disease.

    Science.gov (United States)

    Xu, Wei; Tan, Lan; Wang, Hui-Fu; Jiang, Teng; Tan, Meng-Shan; Tan, Lin; Zhao, Qing-Fei; Li, Jie-Qiong; Wang, Jun; Yu, Jin-Tai

    2015-12-01

    The aetiology of Alzheimer's disease (AD) is believed to involve environmental exposure and genetic susceptibility. The aim of our present systematic review and meta-analysis was to roundly evaluate the association between AD and its modifiable risk factors. We systematically searched PubMed and the Cochrane Database of Systematic Reviews from inception to July 2014, and the references of retrieved relevant articles. We included prospective cohort studies and retrospective case-control studies. 16,906 articles were identified of which 323 with 93 factors met the inclusion criteria for meta-analysis. Among factors with relatively strong evidence (pooled population >5000) in our meta-analysis, we found grade I evidence for 4 medical exposures (oestrogen, statin, antihypertensive medications and non-steroidal anti-inflammatory drugs therapy) as well as 4 dietary exposures (folate, vitamin E/C and coffee) as protective factors of AD. We found grade I evidence showing that one biochemical exposure (hyperhomocysteine) and one psychological condition (depression) significantly increase risk of developing AD. We also found grade I evidence indicative of complex roles of pre-existing disease (frailty, carotid atherosclerosis, hypertension, low diastolic blood pressure, type 2 diabetes mellitus (Asian population) increasing risk whereas history of arthritis, heart disease, metabolic syndrome and cancer decreasing risk) and lifestyle (low education, high body mass index (BMI) in mid-life and low BMI increasing the risk whereas cognitive activity, current smoking (Western population), light-to-moderate drinking, stress, high BMI in late-life decreasing the risk) in influencing AD risk. We identified no evidence suggestive of significant association with occupational exposures. Effective interventions in diet, medications, biochemical exposures, psychological condition, pre-existing disease and lifestyle may decrease new incidence of AD. Published by the BMJ Publishing Group

  5. Analysis of South Carolina hydrogen and fuel cell workers views and opinion leadership behavior: A waiting opportunity?

    Energy Technology Data Exchange (ETDEWEB)

    Besley, John C. [School of Journalism and Mass Communications, University of South Carolina, Columbia, SC 29205 (United States); Baxter-Clemmons, Shannon [South Carolina Hydrogen Fuel Cell Alliance, P.O. Box 12302, Columbia, SC 29201 (United States)

    2010-08-15

    The current study uses quantitative survey results to explore what a near census of hydrogen and fuel cell (HFC) workers in South Carolina (n = 70) say about their HFC experiences and the degree to which these workers can be expected to act as opinion leaders for the field. In general, these workers say they are positive about the environmental, national security, and economic potential of HFC technologies. They further see HFC technologies as having small and manageable levels of risk. A number of these workers exhibit characteristics associated with both issue-specific and general opinion leadership. Issue-specific leadership and positive views about HFC technology were associated with higher levels of self-reported technology-related interpersonal discussion. The study concludes that the existence of workers with positive HFC experiences and a demonstrated interest in telling others about their experiences may represent an opportunity for those charged with promoting HFC development and adoption. Future efforts should explore how HFC workers could be effectively integrated into such efforts as a means of reaching difficult to reach audiences. (author)

  6. Risk analysis of fireworks transport in cargo container ships

    OpenAIRE

    Branka, Ruddy; Marlair, Guy; Nedelec, Brigitte

    2010-01-01

    International audience; The study deals with the analysis of the most suitable configuration for positioning the fireworks containers in the cargo ship in order to minimize the risks for the ship in case of an accident (transmission of fire or deflagration originating from containers filled with fireworks devices to other containers or arising from other containers to the those containing fireworks).

  7. Development Risk Methodology for Whole Systems Trade Analysis

    Science.gov (United States)

    2016-08-01

    in this report is $112,400. DEVELOPMENT RISK METHODOLOGY FOR WHOLE SYSTEMS TRADE ANALYSIS DESTRUCTION NOTICE Destroy by any method that...official endorsement or approval of the use of such commercial hardware or software. The report may not be cited for purposes of advertisement ...4 Figure 4. Criticality and Schedule Overrun

  8. Analysis of Historical Rainfall Data and Associated Risks on Rain ...

    African Journals Online (AJOL)

    Biometrics, GIS and Agro-metrology Research and Support Directorate ... crop failures. This signifies the need for every year rainfall forecasts and their appropriate analysis to have successful planting as well to minimize related risks and ... with several other crops, the exact date and location for the domestication of tef is.

  9. Longitudinal analysis of HIV risk behaviour patterns and their ...

    African Journals Online (AJOL)

    2018-02-06

    Feb 6, 2018 ... To cite this article: Karl Peltzer (2018) Longitudinal analysis of HIV risk behaviour patterns and their predictors among public .... Methods. Study design. This is a longitudinal observational study of TB patients with hazardous or harmful drinking problems in public primary care clinics in South Africa. Sample ...

  10. Quantitative risk analysis as a basis for emergency planning

    Energy Technology Data Exchange (ETDEWEB)

    Yogui, Regiane Tiemi Teruya [Bureau Veritas do Brasil, Rio de Janeiro, RJ (Brazil); Macedo, Eduardo Soares de [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil)

    2009-07-01

    Several environmental accidents happened in Brazil and in the world during the 70's and 80's. This strongly motivated the preparation for emergencies in the chemical and petrochemical industries. Environmental accidents affect the environment and the communities that are neighbor to the industrial facilities. The present study aims at subsidizing and providing orientation to develop Emergency Planning from the data obtained on Quantitative Risk Analysis, elaborated according to the Technical Standard P4.261/03 from CETESB (Sao Paulo Environmental Agency). It was observed, during the development of the research, that the data generated on these studies need a complementation and a deeper analysis, so that it is possible to use them on the Emergency Plans. The main issues that were analyzed and discussed on this study were the reevaluation of hazard identification for the emergency plans, the consequences and vulnerability analysis for the response planning, the risk communication, and the preparation to respond to the emergencies of the communities exposed to manageable risks. As a result, the study intends to improve the interpretation and use of the data deriving from the Quantitative Risk Analysis to develop the emergency plans. (author)

  11. Analysis of operational risk in a Polish coal preparation plant

    Energy Technology Data Exchange (ETDEWEB)

    Cieslak, W.; Sablik, J.; Martyniak, J.; Wycisk, H. [Central Mining Institute, Katowice (Poland)

    2001-07-01

    The article presents methodology and results of studies, which allow one to characterise a coal preparation plant by means of operational risk analysis and to draw conclusions which could be used for making production management and investment decisions. 6 refs., 6 figs., 2 tabs.

  12. Analysis OfProductivity And Risk Factors In Commercial Poultry ...

    African Journals Online (AJOL)

    The study examined the resource usc efficiency nnd occurrence of risk factors in poultry production in osun state, nigeria using the prouuction function nnd bayesian decision model analysis. Data were collected using a set of questionnaire from. 200 poultry farmers selected from five local government areas of the state ...

  13. Risk Analysis Applied in Oil Exploration and Production | Mbanugo ...

    African Journals Online (AJOL)

    The analysis in this work is based on the actual field data obtained from Devon Exploration and Production Inc. The Net Present Value (NPV) and the Expected Monetary Value (EMV) were computed using Excel and Visual Basic to determine the viability of these projects. Although the use of risk management techniques ...

  14. The integration methods of fuzzy fault mode and effect analysis and fault tree analysis for risk analysis of yogurt production

    Science.gov (United States)

    Aprilia, Ayu Rizky; Santoso, Imam; Ekasari, Dhita Murita

    2017-05-01

    Yogurt is a product based on milk, which has beneficial effects for health. The process for the production of yogurt is very susceptible to failure because it involves bacteria and fermentation. For an industry, the risks may cause harm and have a negative impact. In order for a product to be successful and profitable, it requires the analysis of risks that may occur during the production process. Risk analysis can identify the risks in detail and prevent as well as determine its handling, so that the risks can be minimized. Therefore, this study will analyze the risks of the production process with a case study in CV.XYZ. The method used in this research is the Fuzzy Failure Mode and Effect Analysis (fuzzy FMEA) and Fault Tree Analysis (FTA). The results showed that there are 6 risks from equipment variables, raw material variables, and process variables. Those risks include the critical risk, which is the risk of a lack of an aseptic process, more specifically if starter yogurt is damaged due to contamination by fungus or other bacteria and a lack of sanitation equipment. The results of quantitative analysis of FTA showed that the highest probability is the probability of the lack of an aseptic process, with a risk of 3.902%. The recommendations for improvement include establishing SOPs (Standard Operating Procedures), which include the process, workers, and environment, controlling the starter of yogurt and improving the production planning and sanitation equipment using hot water immersion.

  15. RiskChanges Spatial Decision Support system for the analysis of changing multi-hazard risk

    Science.gov (United States)

    van Westen, Cees; Zhang, Kaixi; Bakker, Wim; Andrejchenko, Vera; Berlin, Julian; Olyazadeh, Roya; Cristal, Irina

    2015-04-01

    Within the framework of the EU FP7 Marie Curie Project CHANGES and the EU FP7 Copernicus project INCREO a spatial decision support system was developed with the aim to analyse the effect of risk reduction planning alternatives on reducing the risk now and in the future, and support decision makers in selecting the best alternatives. Central to the SDSS are the stakeholders. The envisaged users of the system are organizations involved in planning of risk reduction measures, and that have staff capable of visualizing and analyzing spatial data at a municipal scale. The SDSS should be able to function in different countries with different legal frameworks and with organizations with different mandates. These could be subdivided into Civil protection organization with the mandate to design disaster response plans, Expert organizations with the mandate to design structural risk reduction measures (e.g. dams, dikes, check-dams etc), and planning organizations with the mandate to make land development plans. The SDSS can be used in different ways: analyzing the current level of risk, analyzing the best alternatives for risk reduction, the evaluation of the consequences of possible future scenarios to the risk levels, and the evaluation how different risk reduction alternatives will lead to risk reduction under different future scenarios. The SDSS is developed based on open source software and following open standards, for code as well as for data formats and service interfaces. Code development was based upon open source software as well. The architecture of the system is modular. The various parts of the system are loosely coupled, extensible, using standards for interoperability, flexible and web-based. The Spatial Decision Support System is composed of a number of integrated components. The Risk Assessment component allows to carry out spatial risk analysis, with different degrees of complexity, ranging from simple exposure (overlay of hazard and assets maps) to

  16. Predicting complication risk in spine surgery: a prospective analysis of a novel risk assessment tool.

    Science.gov (United States)

    Veeravagu, Anand; Li, Amy; Swinney, Christian; Tian, Lu; Moraff, Adrienne; Azad, Tej D; Cheng, Ivan; Alamin, Todd; Hu, Serena S; Anderson, Robert L; Shuer, Lawrence; Desai, Atman; Park, Jon; Olshen, Richard A; Ratliff, John K

    2017-07-01

    OBJECTIVE The ability to assess the risk of adverse events based on known patient factors and comorbidities would provide more effective preoperative risk stratification. Present risk assessment in spine surgery is limited. An adverse event prediction tool was developed to predict the risk of complications after spine surgery and tested on a prospective patient cohort. METHODS The spinal Risk Assessment Tool (RAT), a novel instrument for the assessment of risk for patients undergoing spine surgery that was developed based on an administrative claims database, was prospectively applied to 246 patients undergoing 257 spinal procedures over a 3-month period. Prospectively collected data were used to compare the RAT to the Charlson Comorbidity Index (CCI) and the American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) Surgical Risk Calculator. Study end point was occurrence and type of complication after spine surgery. RESULTS The authors identified 69 patients (73 procedures) who experienced a complication over the prospective study period. Cardiac complications were most common (10.2%). Receiver operating characteristic (ROC) curves were calculated to compare complication outcomes using the different assessment tools. Area under the curve (AUC) analysis showed comparable predictive accuracy between the RAT and the ACS NSQIP calculator (0.670 [95% CI 0.60-0.74] in RAT, 0.669 [95% CI 0.60-0.74] in NSQIP). The CCI was not accurate in predicting complication occurrence (0.55 [95% CI 0.48-0.62]). The RAT produced mean probabilities of 34.6% for patients who had a complication and 24% for patients who did not (p = 0.0003). The generated predicted values were stratified into low, medium, and high rates. For the RAT, the predicted complication rate was 10.1% in the low-risk group (observed rate 12.8%), 21.9% in the medium-risk group (observed 31.8%), and 49.7% in the high-risk group (observed 41.2%). The ACS NSQIP calculator consistently

  17. SU-F-T-243: Major Risks in Radiotherapy. A Review Based On Risk Analysis Literature

    Energy Technology Data Exchange (ETDEWEB)

    López-Tarjuelo, J; Guasp-Tortajada, M; Iglesias-Montenegro, N; Monasor-Denia, P [Servicio de Radiofísica y Protección Radiológica, Consorcio Hospitalario Provincial de Castellón, Castellón de la Plana, España/Spain (Spain); Bouché-Babiloni, A; Morillo-Macías, V; Ferrer-Albiach, C [Servicio de Oncología Radioterápica, Consorcio Hospitalario Provincial de Castellón, Castellón de la Plana, España/Spain (Spain)

    2016-06-15

    Purpose: We present a literature review of risk analyses in radiotherapy to highlight the most reported risks and facilitate the spread of this valuable information so that professionals can be aware of these major threats before performing their own studies. Methods: We considered studies with at least an estimation of the probability of occurrence of an adverse event (O) and its associated severity (S). They cover external beam radiotherapy, brachytherapy, intraoperative radiotherapy, and stereotactic techniques. We selected only the works containing a detailed ranked series of elements or failure modes and focused on the first fully reported quartile as much. Afterward, we sorted the risk elements according to a regular radiotherapy procedure so that the resulting groups were cited in several works and be ranked in this way. Results: 29 references published between 2007 and February 2016 were studied. Publication trend has been generally rising. The most employed analysis has been the Failure mode and effect analysis (FMEA). Among references, we selected 20 works listing 258 ranked risk elements. They were sorted into 31 groups appearing at least in two different works. 11 groups appeared in at least 5 references and 5 groups did it in 7 or more papers. These last sets of risks where choosing another set of images or plan for planning or treating, errors related with contours, errors in patient positioning for treatment, human mistakes when programming treatments, and planning errors. Conclusion: There is a sufficient amount and variety of references for identifying which failure modes or elements should be addressed in a radiotherapy department before attempting a specific analysis. FMEA prevailed, but other studies such as “risk matrix” or “occurrence × severity” analyses can also lead professionals’ efforts. Risk associated with human actions ranks very high; therefore, they should be automated or at least peer-reviewed.

  18. Risk factors for deep vein thrombosis and pulmonary embolism after traumatic injury: A competing risks analysis.

    Science.gov (United States)

    Van Gent, Jan-Michael; Calvo, Richard Yee; Zander, Ashley L; Olson, Erik J; Sise, C Beth; Sise, Michael J; Shackford, Steven R

    2017-12-01

    Venous thromboembolism, including deep vein thrombosis (DVT) and pulmonary embolism (PE), is typically reported as a composite measure of the quality of trauma center care. Given that recent data suggesting postinjury DVT and PE are distinct clinical processes, a better understanding may result from analyzing them as independent, competing events. Using competing risks analysis, we evaluated our hypothesis that the risk factors and timing of postinjury DVT and PE are different. We examined all adult trauma patients admitted to our Level I trauma center from July 2006 to December 2011 who received at least one surveillance duplex ultrasound of the lower extremities and who were at high risk or greater for DVT. Outcomes included DVT and PE events, and time-to-event from admission. We used competing risks analysis to evaluate risk factors for DVT while accounting for PE as a competing event, and vice versa. Of 2,370 patients, 265 (11.2%) had at least one venous thromboembolism event, 235 DVT only, 19 PE only, 11 DVT and PE. Within 2 days of admission, 38% of DVT cases had occurred compared with 26% of PE. Competing risks modeling of DVT as primary event identified older age, severe injury (Injury Severity Score, ≥ 15), mechanical ventilation longer than 4 days, active cancer, history of DVT or PE, major venous repair, male sex, and prophylactic enoxaparin and prophylactic heparin as associated risk factors. Modeling of PE as the primary event showed younger age, nonsevere injury (Injury Severity Score, < 15), central line placement, and prophylactic heparin as relevant factors. The risk factors for PE and DVT after injury were different, suggesting that they are clinically distinct events that merit independent consideration. Many DVT events occurred early despite prophylaxis, bringing into question the preventability of postinjury DVT. We recommend trauma center quality reporting program measures be revised to account for DVT and PE as unique events. Epidemiologic

  19. Analysis of biotechnological hydrogen production efficiency for microorganisms with different types of metabolism, promising directions for further research

    Directory of Open Access Journals (Sweden)

    Людмила Сергіївна Зубченко

    2015-10-01

    Full Text Available The basic biotechnological methods of hydrogen production, namely biological water splitting, using algae or cyanobacteria, dark fermentation and bioelectrochemical systems are analyzed in the article. Biochemical features of hydrogen production by microorganisms with different types of metabolism are reviewed. Disadvantages of each method and the prospects for future research are determined

  20. Scattering matrix analysis for evaluating the photocurrent in hydrogenated-amorphous-silicon-based thin film solar cells.

    Science.gov (United States)

    Shin, Myunghun; Lee, Seong Hyun; Lim, Jung Wook; Yun, Sun Jin

    2014-11-01

    A scattering matrix (S-matrix) analysis method was developed for evaluating hydrogenated amorphous silicon (a-Si:H)-based thin film solar cells. In this approach, light wave vectors A and B represent the incoming and outgoing behaviors of the incident solar light, respectively, in terms of coherent wave and incoherent intensity components. The S-matrix determines the relation between A and B according to optical effects such as reflection and transmission, as described by the Fresnel equations, scattering at the boundary surfaces, or scattering within the propagation medium, as described by the Beer-Lambert law and the change in the phase of the propagating light wave. This matrix can be used to evaluate the behavior of angle-incident coherent and incoherent light simultaneously, and takes into account not only the light scattering process at material boundaries (haze effects) but also nonlinear optical processes within the material. The optical parameters in the S-matrix were determined by modeling both a 2%-gallium-doped zinc oxide transparent conducting oxide and germanium-compounded a-Si:H (a-SiGe:H). Using the S-matrix equations, the photocurrent for an a-Si:H/a-SiGe:H tandem cell and the optical loss in semitransparent a-Si:H solar cells for use in building-integrated photovoltaic applications were analyzed. The developed S-matrix method can also be used as a general analysis tool for various thin film solar cells.