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Sample records for events fuel investigations

  1. Transient dry out in Forsmark 2 during a fast pump runback - course of events, fuel investigations and measures taken

    Energy Technology Data Exchange (ETDEWEB)

    Ramenblad, Eric; Schrire, David [Vattenfall Nuclear Fuel, Jaemtlandsgatan 99, 162 87 Stockholm (Sweden); Schroeder, Bjoern [Forsmarks Kraftgrupp AB, 172 03 Oesthammar (Sweden)

    2009-06-15

    Swedish BWRs operate under the condition that dry out is not accepted for anticipated transients. To guarantee this, extensive work has been done regarding plant models, methodology development and full scope SAR analyses. In addition to this, every cycle is analyzed in detail to determine an operating limit for the minimum critical power ratio (OLMCPR). A course of events on June 13 led about 84 fuel assemblies of Forsmark 2 to exceed the safety limit minimum CPR and 18 of these experienced dry out. This had not been anticipated beforehand, hence, the OLMCPR was too low and did not protect the fuel against the transient dryout. The calculations are made up out of two separate cases. First the plant response was analyzed with the Westinghouse code BISON. Global variables like total core flow, the neutron flux (APRM) and steam dome pressure were determined. After this, boundary conditions regarding inlet temperature, core pressure drop, core power and axial power profile are used on a specific hot channel. The calculations were also compared to those that were available from the plant log, showing good agreement. Vattenfall and the fuel vendors did independent best estimate hot channel analyses to calculate what impact the transient might have had on the fuel. The agreement between different codes (GE: TRACG, Areva: HECHAN and Vattenfall: BISON/SLAVE) was very good showing that the maximum outside cladding temperature was around 450 deg. C. Since the transient leads to a decrease in power and the dry out was of such short duration, it was only the cladding and the outer part of the pellet that experienced a higher temperature than during normal full power operation. The impact on the cladding temperature when rewetting is not credited was also studied, and assuming uncertainties regarding rod power, channel flow and gap size. Rewetting had only a slight impact on the maximum temperature but, of course, a major impact on the duration. The other uncertainties added up

  2. Fuel cell ion-exchange membrane investigation

    Science.gov (United States)

    Toy, M. S.

    1972-01-01

    The present deficiencies in the fluorocarbon sulfonic acid membrane used as the solid polymer electrolyte in the H2/O2 fuel cell are studied. Considered are: Adhesives selection, elastomeric formulations, scavenger exploration, and membrane characterization. The significant data are interpreted and recommendations are given for both short and long range further investigations in two of the four major areas: membrane adhesives and membrane stabilization.

  3. BISON Fuel Performance Analysis of IFA-796 Rod 3 & 4 and Investigation of the Impact of Fuel Creep

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, Brian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sweet, Ryan T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    In order to improve the accident tolerance of light water reactor (LWR) fuel, alternative cladding materials have been proposed to replace the currently used zirconium (Zr)-based alloys. Of these materials, there is a particular focus on iron-chromiumaluminum (FeCrAl) alloys because they exhibit slower oxidation kinetics in high-temperature steam than Zr-alloys. This should decrease the energy release due to oxidation and slow cladding consumption in the presence of high temperature steam. These alloys should also exhibit increased “coping time” in the event of an accident scenario by improving the mechanical performance at high temperatures, allowing greater flexibility to achieve core cooling. As a continuation of the development of these alloys, in-reactor irradiation testing of FeCrAl cladded fuel rods has started. In order to provide insight on the possible behavior of these fuel rods as they undergo irradiation in the Halden Boiling Water Reactor, engineering analysis has been performed using FeCrAl material models implemented into the BISON fuel performance code. This milestone report provides an update on the ongoing development of modeling capability to predict FeCrAl cladding fuel performance and to provide an early look at the possible behavior of planned in-reactor FeCrAl cladding experiments. In particular, this report consists of two separate analyses. The first analysis consists of fuel performance simulations of IFA-796 rod 4 and two segments of rod 3. These simulations utilize previously implemented material models for the C35M FeCrAl alloy and UO2 to provide a bounding behavior analysis corresponding to variation of the initial fuel cladding gap thickness within the fuel rod. The second analysis is an assessment of the fuel and cladding stress states after modification of the fuel creep model that is currently implemented in the BISON fuel performance code. Effects from modifying the fuel creep model were identified for the BISON simulations

  4. Nuclear Forensics Attributing the Source of Spent Fuel Used in an RDD Event

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Mark Robert [Texas A & M Univ., College Station, TX (United States)

    2005-05-01

    An RDD attack against the U.S. is something America needs to prepare against. If such an event occurs the ability to quickly identify the source of the radiological material used in an RDD would aid investigators in identifying the perpetrators. Spent fuel is one of the most dangerous possible radiological sources for an RDD. In this work, a forensics methodology was developed and implemented to attribute spent fuel to a source reactor. The specific attributes determined are the spent fuel burnup, age from discharge, reactor type, and initial fuel enrichment. It is shown that by analyzing the post-event material, these attributes can be determined with enough accuracy to be useful for investigators. The burnup can be found within a 5% accuracy, enrichment with a 2% accuracy, and age with a 10% accuracy. Reactor type can be determined if specific nuclides are measured. The methodology developed was implemented into a code call NEMASYS. NEMASYS is easy to use and it takes a minimum amount of time to learn its basic functions. It will process data within a few minutes and provide detailed information about the results and conclusions.

  5. INVESTIGATION OF PEM FUEL CELL FOR AUTOMOTIVE USE

    Directory of Open Access Journals (Sweden)

    A. K. M. Mohiuddin

    2015-11-01

    Full Text Available This paper provides a brief investigation on suitability of Proton-exchange  membrane fuel cells (PEMFCs as the source of power for transportation purposes. Hydrogen is an attractive alternative transportation fuel. It is the least polluting fuel that can be used in an internal combustion engine (ICE and it is widely available. If hydrogen is used in a fuel cell which converts the chemical energy of hydrogen into electricity, (NOx emissions are eliminated. The investigation was carried out on a  fuel cell car model by implementing polymer electrolyte membrane (PEM types of fuel cell as the source of power to propel the prototype car. This PEMFC has capability to propel the electric motor by converting chemical energy stored in hydrogen gas into useful electrical energy. PEM fuel cell alone is used as the power source for the electric motor without the aid of any other power source such as battery associated with it. Experimental investigations were carried out to investigate the characteristics of fuel cell used and the performance of the fuel cell car. Investigated papameters are the power it develops, voltage, current and speed it produces under different load conditions. KEYWORDS: fuel cell; automotive; proton exchange membrane; polymer electrolyte membrane; internal combustion engine

  6. Investigation of the condition of spent-fuel pool components

    Energy Technology Data Exchange (ETDEWEB)

    Kustas, F.M.; Bates, S.O.; Opitz, B.E.; Johnson, A.B. Jr.; Perez, J.M. Jr.; Farnsworth, R.K.

    1981-09-01

    It is currently projected that spent nuclear fuel, which is discharged from the reactor and then stored in water pools, may remain in those pools for several decades. Other studies have addressed the expected integrity of the spent fuel during extended water storage; this study assesses the integrity of metallic spent fuel pool components. Results from metallurgical examinations of specimens taken from stainless steel and aluminum components exposed in spent fuel pools are presented. Licensee Event Reports (LERs) relating to problems with spent fuel components were assessed and are summarized to define the types of operational problems that have occurred. The major conclusions of this study are: aluminum and stainless steel spent fuel pool components have a good history of performance in both deionized and borated water pools. Although some operational problems involving pool components have occurred, these problems have had minimal impacts.

  7. Investigation Status of Heat Exchange while Boiling Hydrocarbon Fuel

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    D. S. Obukhov

    2006-01-01

    Full Text Available The paper contains analysis of heat exchange investigations while boiling hydrocarbon fuel. The obtained data are within the limits of the S.S. Kutateladze dependence proposed in 1939. Heat exchange at non-stationary heat release has not been investigated. The data for hydrocarbon fuel with respect to critical density of heat flow are not available even for stationary conditions.

  8. Human based roots of failures in nuclear events investigations

    Energy Technology Data Exchange (ETDEWEB)

    Ziedelis, Stanislovas; Noel, Marc; Strucic, Miodrag [Commission of the European Communities, Petten (Netherlands). European Clearinghouse on Operational Experience Feedback for Nuclear Power Plants

    2012-10-15

    This paper aims for improvement of quality of the event investigations in the nuclear industry through analysis of the existing practices, identifying and removing the existing Human and Organizational Factors (HOF) and management related barriers. It presents the essential results of several studies performed by the European Clearinghouse on Operational Experience. Outcomes of studies are based on survey of currently existing event investigation practices typical for nuclear industry of 12 European countries, as well as on insights from analysis of numerous event investigation reports. System of operational experience feedback from information based on event investigation results is not enough effective to prevent and even to decrease frequency of recurring events due to existing methodological, HOF-related and/or knowledge management related constraints. Besides that, several latent root causes of unsuccessful event investigation are related to weaknesses in safety culture of personnel and managers. These weaknesses include focus on costs or schedule, political manipulation, arrogance, ignorance, entitlement and/or autocracy. Upgrades in safety culture of organization's personnel and its senior management especially seem to be an effective way to improvement. Increasing of competencies, capabilities and level of independency of event investigation teams, elaboration of comprehensive software, ensuring of positive approach, adequate support and impartiality of management could also facilitate for improvement of quality of the event investigations. (orig.)

  9. Summary of 1991--1992 misadministration event investigations

    Energy Technology Data Exchange (ETDEWEB)

    Ostrom, L.T.; Leahy, T.J.; Novack, S.D. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

    1994-03-01

    Investigation team composed of representatives of the Idaho National Engineering Laboratory (INEL), the US Nuclear Regulatory Commission (NRC), and subcontracts investigated and analyzed seven misadministration events selected by the NRC concerning medical radioisotopes. Each team was led by an INEL member and depending on the nature of the event, included three or more team members with appropriate expertise in radiation oncology, medical physics, nuclear medicine technology, risk analysis, and human factors. The investigations focused on causes of the event, consequences, mitigating actions, and corrective actions. The major findings are described in this report.

  10. Porosimetry as an effective method of fuel cell investigation

    Energy Technology Data Exchange (ETDEWEB)

    Kazarinov, V.E.

    1996-04-01

    A porosimetric method is described for the investigation of all kinds of porous materials including soft or frail materials and powders. The method is well suited for the investigation of electrodes in fuel cells and batteries. The method is nondestructive and allows for repeated measurements on the same sample.

  11. LPG as a Fuel for Diesel Engines-Experimental Investigations

    Science.gov (United States)

    Cristian Nutu, Nikolaos; Pana, Constantin; Negurescu, Niculae; Cernat, Alexandru; Mirica, Ionel

    2017-10-01

    The main objective of the paper is to reduce the pollutant emissions of a compression ignition engine, fuelling the engine with liquefied petroleum gas (LPG), aiming to maintain the energetic performances of the engine. To optimise the engine operation a corelation between the substitute ratio of the diesel fuel with LPG and the adjustments for the investigated regimens must be made in order to limit the maximum pressure and smoke level, knock and rough engine functioning, fuel consumption and the level of the pollutant emissions. The test bed situated in the Thermotechnics, Engines, Thermal Equipments and Refrigeration Instalations Department was adapted to be fuelled with liquefied petroleum gas. A conventional LPG fuelling instalation was adopted, consisting of a LPG tank, a vaporiser, conections between the tank and the vaporiser and a valve to adjust the gaseous fuel flow. Using the diesel-gas methode, in the intake manifold of the engine is injected LPG in gaseous aggregation state and the airr-LPG homogeneous mixture is ignited from the flame appeared in the diesel fuel sprays. To maintain the engine power at the same level like in the standard case of fuelling only with diesel fuel, for each investigated operate regimen the diesel fuel dose was reduced, being energetically substituted with LPG. The engine used for experimental investigations is a turbocharged truck diesel engine with a 10.34 dm3 displacement. The investigated working regimen was 40% load and 1750 rpm and the energetic substitute ratios of the diesel fuel with LPG was situated between [0-25%].

  12. Investigation of Auto-ignition of Several Single Fuels

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    Firmansyaha

    2014-07-01

    Full Text Available HCCI operating principals have been widely investigated yet the uncontrollable combustion of HCCI is the major obstacle in its development. This paper is trying to increase the understanding on the auto-ignition and combustion process of several fuels to be applied in HCCI combustion system. The investigation includes the combustion behavior of 4 fuels, gasoline (RON95, diesel, n-heptane, isooctane, The investigation was done in constant volume chamber with elevated temperature (800°C. Four lambdas were tested for each fuel namely 0.8, 1, 1.2 and 2. It is found that these fuels can be categorized into two major categories based on combustion characteristics, homogeneous and diffusive combustion. Gasoline and isooctane, homogeneous combustion, shows almost the same behavior where the increase in lambda will increase the combustion delay even though isooctane shows much longer delayed compared to gasoline. While diesel and n-heptane, diffusive combustion, has no ignition delay yet showing different behavior on the later parts of the combustion where diesel effecting 10-90% combustion stage while n-heptane on 90-100%.

  13. Fuel aspects of Beyond Design Basis Event analyses for the Fast Flux Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, A. Jr.; Kessler, S.F.; Dobbin, K.D.; Waltar, A.E.

    1990-04-01

    Analyses of two Beyond Design Basis Events (transient overpower without scram and loss of flow without scram) were performed for four different core designs in the Fast Flux Test Facility using the SASSYS/SAS4A accident analysis computer code. The four core designs used the following fuels: mixed oxide, binary metal, enriched uranium oxide, and mixed nitride. Based on the numerical results for these four different fuels, a qualitative relative safety ranking was made. Nitride fuel gave the best safety performance, followed by enriched uranium oxide, binary metal, and mixed oxide. 7 refs., 6 figs., 4 tabs.

  14. An investigation of synthetic fuel production via chemical looping.

    Science.gov (United States)

    Zeman, Frank; Castaldi, Marco

    2008-04-15

    Producing liquid hydrocarbon fuels with a reduced greenhouse gas emissions profile would ease the transition to a carbon-neutral energy sector with the transportation industry being the immediate beneficiary followed by the power industry. Revolutionary solutions in transportation, such as electricity and hydrogen, depend on the deployment of carbon capture and storage technologies and/or renewable energy systems. Additionally, high oil prices may increase the development of unconventional sources, such as tar sands, that have a higher emissions profile. One process that is gaining interest is a system for producing reduced carbon fuels though chemical looping technologies. An investigation of the implications of such a process using methane and carbon dioxide that is reformed to yield methanol has been done. An important aspect of the investigation is the use of off-the-shelf technologies to achieve the results. The ability of the process to yield reduced emissions fuels depends on the source for the feed and process heat. For the range of conditions considered, the emissions profile of methanol produced in this method varies from 0.475 to 1.645 moles carbon dioxide per mole methanol. The upper bound can be lowered to 0.750 by applying CCS and/ or using nonfossil heat sources for the reforming. The process provides an initial pathway to incorporate CO2 into fuels independent of electrolytic hydrogen or developments in other sectors of the economy.

  15. Investigation and Mitigation of Degradation in Hydrogen Fuel Cells

    Science.gov (United States)

    Mandal, Pratiti

    The ever increasing demand of petroleum in the transport sector has led to depletion of low cost/low risk reserves, increased level of pollution, and greenhouse gas emissions that take a heavy toll on the environment as well as the national economy. There is an urgent need to utilize alternative energy resources along with an efficient and affordable energy conversion system to arrest environmental degradation. Polymer electrolyte fuel cells (PEFCs) show great promise in this regard, they use hydrogen gas as a fuel that electrochemically reacts with air to produce electrical energy and water as the by product. In a fuel cell electric vehicle (FCEV), these zero tail pipe emission systems offer high efficiency and power density for medium-heavy duty and long range transportation. However, PEFC technology is currently challenged by its limited durability when subjected to harsh and adverse operating conditions and transients that arises during the normal course of vehicle operation. The hydrogen-based fuel cell power train for electric vehicles must achieve high durability while maintaining high power efficiency and fuel economy in order to equal the range and lifetime of an internal-combustion engine vehicle. The technology also needs to meet the cost targets to make FCEVs a commercial success. In this dissertation, one of the degradation phenomena that severely impede the durability of the system has been investigated. In scenarios where the cell becomes locally starved of hydrogen fuel, "cell reversal" occurs, which causes the cell to consume itself through carbon corrosion and eventually fail. Carbon corrosion in the anode disrupts the original structure of the electrode and can cause undesirable outcomes like catalyst particle migration, aggregation, loss of structural and chemical integrity. Through a comprehensive study using advanced electrochemical diagnostics and high resolution 3D imaging, a new understanding to extend PEFC life time and robustness by

  16. Investigation of charge dissipation in jet fuel in a dielectric fuel tank

    Science.gov (United States)

    Kitanin, E. L.; Kravtsov, P. A.; Trofimov, V. A.; Kitanina, E. E.; Bondarenko, D. A.

    2017-09-01

    The electrostatic charge dissipation process in jet fuel in a polypropylene tank was investigated experimentally. Groundable metallic terminals were installed in the tank walls to accelerate the dissipation process. Several sensors and an electrometer with a current measuring range from 10-11 to 10-3 A were specifically designed to study the dissipation rates. It was demonstrated that thanks to the sensors and the electrometer one can obtain reliable measurements of the dissipation rate and look at how it is influenced by the number and locations of the terminals. Conductivity of jet fuel and effective conductivity of the tank walls were investigated in addition. The experimental data agree well with the numerical simulation results obtained using COMSOL software package.

  17. Investigation of stainless steel clad fuel rod failures and fuel performance in the Connecticut Yankee Reactor. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Pasupathi, V.; Klingensmith, R. W.

    1981-11-01

    Significant levels of fuel rod failures were observed in the batch 8 fuel assemblies of the Connecticut Yankee reactor. Failure of 304 stainless steel cladding in a PWR environment was not expected. Therefore a detailed poolside and hot cell examination program was conducted to determine the cause of failure and identify differences between batch 8 fuel and previous batches which had operated without failures. Hot cell work conducted consisted of detailed nondestructive and destructive examination of fuel rods from batches 7 and 8. The results indicate that the batch 8 failure mechanism was stress corrosion cracking initiating on the clad outer surface. The sources of cladding stresses are believed to be (a) fuel pellet chips wedged in the cladding gap, (b) swelling of highly nondensifying batch 8 fuel and (c) potentially harmful effects of a power change event that occurred near the end of the second cycle of irradiation for batch 8.

  18. Investigation of Nucleation Events in Wintertime Beijing, China

    Science.gov (United States)

    Zheng, Jun; Ma, Yan; Yang, Dongsen; Shi, Xiaowen; Wang, Xing

    2017-04-01

    Nucleation processes contribute substantial secondary aerosols in the atmosphere, which often lead to severe air pollution episodes in China, especially in heavily populated urban area. In this work, we conducted field observations of nucleation events in a rural site of Beijing, from January to March 2016. Nucleation events were frequently observed during the measurement period. The nucleation rates of 1.0 nm diameter aerosol (J1) were determined from direct measurements of particle size distribution of 1.4 - 3.0 nm by a particle size magnifier (PSM) with a value up to a few hundreds particles cm-3 s-1, significantly higher than what we observed during CAREBeijing 2008. Meanwhile, gaseous sulfuric acid (H2SO4) was measured with an atmospheric pressure ionization high-resolution time-of-flight chemical ionization mass spectrometer (API-HR-ToF-CIMS). H2SO4 dimers and sub-3 nm aerosols showed excellent correlations during the nucleation events. NH3 was also observed by another chemical ionization mass spectrometer with a value ranging from a few ppbv up to 20 ppbv. Cold ambient temperature (less than -10°C) and high NH3 concentration may explain the unusually high nucleation rates, which could contribute to the winder haze formation in the urban area of Beijing and should be investigated in more details.

  19. Experimental Investigation of Turbine Vane Heat Transfer for Alternative Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Nix, Andrew Carl [West Virginia Univ., Morgantown, WV (United States)

    2015-03-23

    The focus of this program was to experimentally investigate advanced gas turbine cooling schemes and the effects of and factors that contribute to surface deposition from particulate matter found in coal syngas exhaust flows on turbine airfoil heat transfer and film cooling, as well as to characterize surface roughness and determine the effects of surface deposition on turbine components. The program was a comprehensive, multi-disciplinary collaborative effort between aero-thermal and materials faculty researchers and the Department of Energy, National Energy Technology Laboratory (NETL). The primary technical objectives of the program were to evaluate the effects of combustion of syngas fuels on heat transfer to turbine vanes and blades in land-based power generation gas turbine engines. The primary questions to be answered by this investigation were; What are the factors that contribute to particulate deposition on film cooled gas turbine components? An experimental program was performed in a high-temperature and pressure combustion rig at the DOE NETL; What is the effect of coal syngas combustion and surface deposition on turbine airfoil film cooling? Deposition of particulate matter from the combustion gases can block film cooling holes, decreasing the flow of the film coolant and the film cooling effectiveness; How does surface deposition from coal syngas combustion affect turbine surface roughness? Increased surface roughness can increase aerodynamic losses and result in decreased turbine hot section efficiency, increasing engine fuel consumption to maintain desired power output. Convective heat transfer is also greatly affected by the surface roughness of the airfoil surface; Is there any significant effect of surface deposition or erosion on integrity of turbine airfoil thermal barrier coatings (TBC) and do surface deposits react with the TBC in any way to decrease its thermal insulating capability? Spallation and erosion of TBC is a persistent problem in

  20. Retrofitting a spent fuel pool spray system for alternative cooling as a strategy for beyond design basis events

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Christoph; Vujic, Zoran [Westinghouse Electric Germany GmbH, Mannheim (Germany)

    2017-06-15

    Due to requirements for nuclear power plants to withstand beyond design basis accidents, including events such as happened in 2011 in the Fukushima Daiichi Nuclear Power Plant in Japan, alternative cooling of spent fuel is needed. Alternative spent fuel cooling can be provided by a retrofitted spent fuel pool spray system based on the AP1000 plant design. As part of Krsko Nuclear Power Plant's Safety Upgrade Program, Krsko Nuclear Power Plant decided on, and Westinghouse successfully designed a retrofit of the AP1000 {sup registered} plant spent fuel pool spray system to provide alternative spent fuel cooling.

  1. Young offenders' experiences of traumatic life events: a qualitative investigation.

    Science.gov (United States)

    Paton, Joni; Crouch, William; Camic, Paul

    2009-01-01

    This investigation aimed to look at how a group of young offenders attending an inner-city youth offending team experienced adverse and traumatic life events. A qualitative approach was used and semi-structured interviews were conducted with eight young offenders about their perceptions of difficult experiences and the effects of such events. The interviews were analysed using Interpretative Phenomenological Analysis (Smith, Jarman, & Osborn, 1999). Analysis of the accounts yielded a number of themes. Young offenders experienced violence at home, in the community and in custody. Instability and transitions emerged as important themes in relation to school and home. Deprivation was experienced both in terms of poverty and the literal and emotional absence of parents. A variety of cognitive, emotional and behavioural responses to adverse/traumatic experiences were identified, including a blocking out of painful experience and aggression to self and others. There were barriers to seeking or making use of professional support. Custody appeared to offer an opportunity to reflect on and re-evaluate life trajectory. The study concluded that greater consideration of trauma when carrying out assessments would enable ;at risk' young offenders to be identified using clinical interviewing along side standardized measures to aid assessment of the complexity and uniqueness of the response to trauma.

  2. Investigation of Lubrication Properties of Petroleum Fuel and Biohydrocarbon Blends

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    Gawron Bartosz

    2016-07-01

    Full Text Available The paper covers issues regarding lubricity of petroleum fuels used in piston and turbine engines, containing hydrocarbon biocomponents. Basing on available literature it can be said that the most prospective fuel components are biohydrocarbons. The paper describes effect of biohydrocarbons included in aviation fuel and diesel fuel on lubricity of such blends. The analysis covers two processes for obtaining biohydrocarbons, the HVO and the Fischer-Tropsch process. Due to problems with actual products acquiring, biohydrocarbons models representing chemically the actual ones from specific process. Lubricity testing was carried out according to standard test methods.

  3. Evidence of fuels management and fire weather influencing fire severity in an extreme fire event

    Science.gov (United States)

    Lydersen, Jamie M; Collins, Brandon M.; Brooks, Matthew L.; Matchett, John R.; Shive, Kristen L.; Povak, Nicholas A.; Kane, Van R.; Smith, Douglas F.

    2017-01-01

    Following changes in vegetation structure and pattern, along with a changing climate, large wildfire incidence has increased in forests throughout the western U.S. Given this increase there is great interest in whether fuels treatments and previous wildfire can alter fire severity patterns in large wildfires. We assessed the relative influence of previous fuels treatments (including wildfire), fire weather, vegetation and water balance on fire severity in the Rim Fire of 2013. We did this at three different spatial scales to investigate whether the influences on fire severity changed across scales. Both fuels treatments and previous low to moderate severity wildfire reduced the prevalence of high severity fire. In general, areas without recent fuels treatments and areas that previously burned at high severity tended to have a greater proportion of high severity fire in the Rim Fire. Areas treated with prescribed fire, especially when combined with thinning, had the lowest proportions of high severity. Proportion of the landscape burned at high severity was most strongly influenced by fire weather and proportional area previously treated for fuels or burned by low to moderate severity wildfire. The proportion treated needed to effectively reduce the amount of high fire severity fire varied by spatial scale of analysis, with smaller spatial scales requiring a greater proportion treated to see an effect on fire severity. When moderate and high severity fire encountered a previously treated area, fire severity was significantly reduced in the treated area relative to the adjacent untreated area. Our results show that fuels treatments and low to moderate severity wildfire can reduce fire severity in a subsequent wildfire, even when burning under fire growth conditions. These results serve as further evidence that both fuels treatments and lower severity wildfire can increase forest resilience.

  4. Evidence of fuels management and fire weather influencing fire severity in an extreme fire event.

    Science.gov (United States)

    Lydersen, Jamie M; Collins, Brandon M; Brooks, Matthew L; Matchett, John R; Shive, Kristen L; Povak, Nicholas A; Kane, Van R; Smith, Douglas F

    2017-10-01

    Following changes in vegetation structure and pattern, along with a changing climate, large wildfire incidence has increased in forests throughout the western United States. Given this increase, there is great interest in whether fuels treatments and previous wildfire can alter fire severity patterns in large wildfires. We assessed the relative influence of previous fuels treatments (including wildfire), fire weather, vegetation, and water balance on fire-severity in the Rim Fire of 2013. We did this at three different spatial scales to investigate whether the influences on fire severity changed across scales. Both fuels treatments and previous low to moderate-severity wildfire reduced the prevalence of high-severity fire. In general, areas without recent fuels treatments and areas that previously burned at high severity tended to have a greater proportion of high-severity fire in the Rim Fire. Areas treated with prescribed fire, especially when combined with thinning, had the lowest proportions of high severity. The proportion of the landscape burned at high severity was most strongly influenced by fire weather and proportional area previously treated for fuels or burned by low to moderate severity wildfire. The proportion treated needed to effectively reduce the amount of high severity fire varied by spatial scale of analysis, with smaller spatial scales requiring a greater proportion treated to see an effect on fire severity. When moderate and high-severity fire encountered a previously treated area, fire severity was significantly reduced in the treated area relative to the adjacent untreated area. Our results show that fuels treatments and low to moderate-severity wildfire can reduce fire severity in a subsequent wildfire, even when burning under fire growth conditions. These results serve as further evidence that both fuels treatments and lower severity wildfire can increase forest resilience. © 2017 by the Ecological Society of America.

  5. INVESTIGATION ON THE FLAME EXTINCTION LIMIT OF FUEL BLENDS

    Energy Technology Data Exchange (ETDEWEB)

    Ahsan R. Choudhuri

    2005-02-01

    Lean flame extinction limits of binary fuel mixtures of methane (CH{sub 4}), propane (C{sub 3}H{sub 8}), and ethane (C{sub 2}H{sub 6}) were measured using a twin-flame counter-flow burner. Experiments were conducted to generate an extinction equivalence ratio vs. global stretch rate plot and an extrapolation method was used to calculate the equivalence ratio corresponding to an experimentally unattainable zero-stretch condition. The foregoing gases were selected because they are the primary constitutes of natural gas, which is the primary focus of the present study. To validate the experimental setup and methodology, the flame extinction limit of pure fuels at zero stretch conditions were also estimated and compared with published values. The lean flame extinction limits of methane (f{sub ext} = 4.6%) and propane (f{sub ext} = 2.25%) flames measured in the present study agreed with the values reported in the literature. It was observed that the flame extinction limit of fuel blends have a polynomial relation with the concentration of component fuels in the mixture. This behavior contradicts with the commonly used linear Le Chatelier's approximation. The experimentally determined polynomial relations between the flame extinction limits of fuel blends (i.e. methane-propane and methane-ethane) and methane concentration are as follows: (1) Methane-Propane--%f{sub ext} = (1.05 x 10{sup -9}) f{sup 5}-(1.3644 x 10{sup -7}) f{sup 4}+(6.40299 x 10{sup -6}) f{sup 3}-(1.2108459 x 10{sup -4}) f{sup 2}+(2.87305329 x 10{sup -3}) f+2.2483; (2) Methane-Ethane--%f{sub ext} = (2.1 x 10{sup -9})f{sup 5}-(3.5752 x 10{sup -7}) f{sup 4}+(2.095425 x 10{sup -5}) f{sup 3}-(5.037353 x 10{sup -4}) f{sup 2} + 6.08980409 f + 2.8923. Where f{sub ext} is the extinction limits of methane-propane and methane-ethane fuel blends, and f is the concentration (% volume) of methane in the fuel mixture. The relations were obtained by fitting fifth order curve (polynomial regression) to

  6. The investigation of effects specific fuel comsumption and emissions fuel mixtures nitromethane

    Directory of Open Access Journals (Sweden)

    Samet Çelebi

    2013-08-01

    Full Text Available In this study, changes of specific fuel consumption and exhaust emmission values of chemical produced nitromethane are compared with values of gasoline fuel. In motor tests conducted at full load, gasoline mixture including % 5 nitromethane yield decreased specific fuel consumption value of 3200 min-1 and low engine speed of % 6,18 percentage. On the other hand, engine power is increased. While CO and HC emissions were observed to be less than gasoline, CO2 and NOx emissions remained to be increased. In performed tests, it is also observed that when mixing nitromethane with % 10 more gasoline, over knocking and unstable motor behavior is observed.

  7. Investigation of a piezoelectric droplet delivery method for fuel injection and physical property evaluation

    Science.gov (United States)

    Zhao, Wei; Menon, Shyam

    2017-11-01

    A piezoelectric droplet generator is investigated to deliver liquid hydrocarbon fuels to a micro-combustor application. Besides fuel delivery, the setup is intended to measure fuel physical properties such as viscosity and surface tension. These properties are highly relevant to spray generation in internal combustion engines. Accordingly, a drop-on-demand piezoelectric dispenser is used to generate fuel droplet trains, which are studied using imaging and Phase Doppler Particle Anemometry (PDPA). The diagnostics provide information regarding droplet size and velocity and their evolution over time. The measurements are correlated with results from one-dimensional (1D) models that incorporate sub-models for piezo-electric actuation and droplet vaporization. By validating the 1D models for fuels with known physical properties, a technique is developed that has the capability to meter low-vapor pressure liquid fuels to the microcombustor and use information from the droplet train to calculate physical properties of novel fuels.

  8. Cardiovascular thromboembolic events associated with febuxostat: investigation of cases from the FDA adverse event reporting system database.

    Science.gov (United States)

    Gandhi, Pranav K; Gentry, William M; Bottorff, Michael B

    2013-06-01

    Uloric (Febuxostat) has been linked with cardiovascular thromboembolic events in gout patients. However, no post-marketing data analysis has investigated these drug-associated adverse event reports. The study objective was to identify febuxostat-associated cardiovascular thromboembolic event reports in the US using the Food and Drug Administration adverse event reporting system (AERS) database. Reports listing uloric and febuxostat as the suspect drug and cardiovascular thromboembolic events (combined in a single term based on adverse event reports of myocardial infarction, stroke, among others) as the adverse event were extracted from the drug's approval date through the fourth quarter of 2011. Bayesian statistics within the neural network architecture was implemented to identify potential signals of febuxostat-associated cardiovascular thromboembolic events. A potential signal for the drug-adverse event combination reports is generated when the lower limit of the 95% two-sided confidence interval of the information component (IC), denoted by IC025 is greater than zero. Twenty-one combination reports of febuxostat-associated cardiovascular thromboembolic events were identified in gout patients in the US. The mean age of combination cases was 64 years. Potential signals (IC025 = 4.09) was generated for combination reports of febuxostat-associated cardiovascular thromboembolic events. AERS indicated potential signals of febuxostat-associated cardiovascular thromboembolic events. AERS is not capable of establishing the causal link and detecting the true frequency of an adverse event associated with a drug. The positive IC value found in this study merits continued surveillance and assessment of cardiovascular thromboembolic events associated with Febuxostat. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Safety case for the disposal of spent nuclear fuel at Olkiluoto. Features, events and processes 2012

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-12-15

    Features, Events and Processes sits within Posiva Oy's Safety Case 'TURVA-2012' portfolio and has the objective of presenting the main features, events and processes (FEPs) that are considered to be potentially significant for the long-term safety of the planned KBS-3V repository for spent nuclear fuel at Olkiluoto. The primary purpose of this report is to support Performance Assessment, Formulation of Radionuclide Release Scenarios, Assessment of the Radionuclide Release Scenarios for the Repository System and Biosphere Assessment by ensuring that the scenarios are comprehensive and take account of all significant FEPs. The main FEPs potentially affecting the disposal system are described for each relevant subsystem component or barrier (i.e. the spent nuclear fuel, the canister, the buffer and tunnel backfill, the auxiliary components, the geosphere and the surface environment). In addition, a small number of external FEPs that may potentially influence the evolution of the disposal system are described. The conceptual understanding and operation of each FEP is described, together with the main features (variables) of the disposal system that may affect its occurrence or significance. Olkiluoto-specific issues are considered when relevant. The main uncertainties (conceptual and parameter/data) associated with each FEP that may affect understanding are also documented. Indicative parameter values are provided, in some cases, to illustrate the magnitude or rate of a process, but it is not the intention of this report to provide the complete set of numerical values that are used in the quantitative safety assessment calculations. Many of the FEPs are interdependent and, therefore, the descriptions also identify the most important direct couplings between the FEPs. This information is used in the formulation of scenarios to ensure the conceptual models and calculational cases are both comprehensive and representative. (orig.)

  10. Impact of urbanization on tropical mesoscale events: investigation of three heavy rainfall events

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, Prashant; Shivappa, Himesh [CSIR Centre for Mathematical Modeling and Computer Simulation, Bangalore (India); Goud, Bharamanagoudra S. [UVCE, Jnana Bharathi, Dept. of civil Engineering, Bangalore Univ., Bangalore (India)

    2010-06-15

    The growing worldwide trend in urbanization leading to the development of mega cities is likely to have a strong impact on local weather and climate through a variety of effects like Urban Heat Island (UHI), increased surface heat fux and atmospheric air temperature. These changes, in turn, can have a significant impact on energy demands for cooling or warming. It is, therefore, necessary to study these effects through models that comprehensively describe the local atmospheric dynamics in a large-scale environment. In this work we examine the impact of urbanization on the evolution and dynamics of three heavy rainfall events that occurred over Indian cities (Mumbai, Bangalore and Chennai) in different seasons using the mesoscale atmospheric model MM5, version-3. Numerical experiments were carried out for each of the events using a 3-nest configuration with a 2 km resolution for the innermost domain. Simulations were carried out for two scenarios; partially urban and fully urban. It was found that urbanization drastically increases maximum surface temperature (ground temperature) for both Mumbai and Chennai event, while for the Bangalore event, the change is mostly in the minimum temperature. In general it was found that urbanization increases the Diurnal Temperature Range (DTR). These differences in temperature, prominent in the pre-rainfall period, dissipate during the event window. Urbanization was also found to increase the temperature throughout the depth of the atmospheric column. Of primary concern is the change in the intensity and duration of extreme weather events. Our results show that increased urbanization affects both intensity and spatial distribution of rain. Partial urbanization was found to be associated with more total rain, larger spatial extend of distribution and less intensity, while the converse is true for the fully urban scenario. The impact of the spatial extant of urbanization (large city vs. megacity) was also examined through an

  11. Numerical investigation of hydraulic ram effects in fuel tanks

    Science.gov (United States)

    Helwig, C. H. M.; Sachs, G. W.; Seidel, K. G. K.

    1987-10-01

    This paper presents results from two-dimensional and three-dimensional numerical simulations of projectiles striking fuel filled tanks. The calculations reproduce former measurements of velocity losses of the penetrating projectile during the shock phase. It is further shown that the damage of the tank rear wall is practically independent of the distance to the front wall but can be reduced by isolating porous material or additional walls in the tank.

  12. Investigation of the effects of renewable diesel fuels on engine performance, combustion, and emissions

    KAUST Repository

    Ogunkoya, Dolanimi

    2015-01-01

    A study was undertaken to investigate renewable fuels in a compression-ignition internal combustion engine. The focus of this study was the effect of newly developed renewable fuels on engine performance, combustion, and emissions. Eight fuels were investigated, and they include diesel, jet fuel, a traditional biodiesel (fatty acid methyl ester: FAME), and five next generation biofuels. These five fuels were derived using a two-step process: hydrolysis of the oil into fatty acids (if necessary) and then a thermo-catalytic process to remove the oxygen via a decarboxylation reaction. The fuels included a fed batch deoxygenation of canola derived fatty acids (DCFA), a fed batch deoxygenation of canola derived fatty acids with varying amounts of H2 used during the deoxygenation process (DCFAH), a continuous deoxygenation of canola derived fatty acids (CDCFA), fed batch deoxygenation of lauric acid (DLA), and a third reaction to isomerize the products of the deoxygenated canola derived fatty acid alkanes (IPCF). Diesel, jet fuel, and biodiesel (FAME) have been used as benchmarks for comparing with the newer renewable fuels. The results of the experiments show slightly lower mechanical efficiency but better brake specific fuel consumption for the new renewable fuels. Results from combustion show shorter ignition delays for most of the renewable (deoxygenated) fuels with the exception of fed batch deoxygenation of lauric acid. Combustion results also show lower peak in-cylinder pressures, reduced rate of increase in cylinder pressure, and lower heat release rates for the renewable fuels. Emission results show an increase in hydrocarbon emissions for renewable deoxygenated fuels, but a general decrease in all other emissions including NOx, greenhouse gases, and soot. Results also demonstrate that isomers of the alkanes resulting from the deoxygenation of the canola derived fatty acids could be a potential replacement to conventional fossil diesel and biodiesel based on the

  13. Building 3D Event Logs for Video Investigation

    NARCIS (Netherlands)

    Dang, T.K.; Worring, M.; Bui, T.D.

    2015-01-01

    In scene investigation, creating a video log captured using a handheld camera is more convenient and more complete than taking photos and notes. By introducing video analysis and computer vision techniques, it is possible to build a spatio-temporal representation of the investigation. Such a

  14. Investigating fuel-cell transport limitations using hydrogen limiting current

    OpenAIRE

    Spingler, FB; Phillips, A; Schuler, T; Tucker, MC; Weber, AZ

    2017-01-01

    © 2017 Hydrogen Energy Publications LLC Reducing mass-transport losses in polymer-electrolyte fuel cells (PEFCs) is essential to increase their power density and reduce overall stack cost. At the same time, cost also motivates the reduction in expensive precious-metal catalysts, which results in higher local transport losses in the catalyst layers. In this paper, we use a hydrogen-pump limiting-current setup to explore the gas-phase transport losses through PEFC catalyst layers and various ga...

  15. Theoretical investigation of chemical and physical properties of gaseous fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hermann, Fredrik

    1999-12-01

    This thesis is discussing the chemical and physical properties of different gaseous fuels. A mapping of about seventy gaseous fuels resulted in eleven type gases, these gases have mainly five components (inerts, H{sub 2}, CO, CH{sub 4} and higher order of hydrocarbons) of different quantities. Calculations of heating value and Wobbe number have been done. Dew point temperatures have been estimated by using three different programs. Flammability limits, laminar flame speed and auto ignition temperatures have been calculated by using a kinetic and chemical program developed by Mauss. Flammability limits have been compared with Le Chatelier's law and measurements. Problems related to combustion such as flash back, lift off and instability are closely connected with flame speed and flow patterns. These problems are discussed in terms of laminar flame speed and Reynolds' number. The main results of this study were: Auto ignition temperature for gas mixtures behavior is very complex and unpredictable. In general small quantities of hydrogen decrease the temperature of auto ignition. The calculations of flammability limits by the kinetic and chemical software showed good agreement to measurements. Low Btu gases requires large flow area in order to avoid large pressure drop.

  16. Interferometrical techniques for the investigation of dynamic events

    Science.gov (United States)

    Pedrini, Giancarlo; Alexeenko, Igor; Osten, Wolfgang

    2013-06-01

    The availability of high resolution CCD and CMOS sensors together with the increasing computer capacity have enabled the development of different interferometrical techniques (speckle interferometry, digital holography, digital sherography) which are well suited for real time measurements. Two or more interferograms are recorded on a digital sensor at different times and the deformation of the object occurring between the exposures is calculated from the phase change. Since the process to investigate can be very fast we cannot use the well-known temporal phase shift method for the determination of the phase but we use a spatial carrier method which allows to determine that phase from one single hologram. We will show that this method can be used as well for shearography. Applications of digital holographic techniques for the investigation of vibrations, defect detection in mechanical structure and time resolved measurement of deformation of microelectromechanical systems (MEMS) are presented together with some investigation of mechanical structures by using digital shearography with spatial carrier.

  17. Investigation of low-cost LNG vehicle fuel tank concepts. Final report

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, J.E.; Siahpush, A. [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States). Idaho National Engineering and Environmental Lab.

    1998-02-01

    The objective of this study was to investigate development of a low-cost liquid natural gas (LNG) vehicle fuel storage tank with low fuel boil-off, low tank pressure, and high safety margin. One of the largest contributors to the cost of converting a vehicle to LNG is the cost of the LNG fuel tank. To minimize heat leak from the surroundings into the low-temperature fuel, these tanks are designed as cryogenic dewars with double walls separated by an evacuated insulation space containing multi-layer insulation. The cost of these fuel tanks is driven by this double-walled construction, both in terms of materials and labor. The primary focus of the analysis was to try to devise a fuel tank concept that would allow for the elimination of the double-wall requirement. Results of this study have validated the benefit of vacuum/MLI insulation for LNG fuel tanks and the difficulty in identifying viable alternatives. The thickness of a non-vacuum insulation layer would have to be unreasonably large to achieve an acceptable non-venting hold time. Reasonable hold times could be achieved by using an auxiliary tank to accept boil-off vapor from a non-vacuum insulated primary tank, if the vapor in the auxiliary tank can be stored at high pressure. The primary focus of the analysis was to try to devise a fuel tank concept that allowed for the elimination of the double-wall requirement. Thermodynamic relations were developed for analyzing the fuel tank transient response to heat transfer, venting of vapor, and out-flow of either vapor or liquid. One of the major costs associated with conversion of a vehicle to LNG fuel is the cost of the LNG fuel tank. The cost of these tanks is driven by the cryogenic nature of the fuel and by the fundamental design requirements of long non-venting hold times and low storage pressure.

  18. Investigation of Electrochemical Recovery of Zirconium from Spent Nuclear Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hwang, II-Soon [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-06-01

    This project uses both modeling and experimental studies to design optimal electrochemical technology methods for recovery of zirconium from used nuclear fuel rods for more effective waste management. The objectives are to provide a means of efficiently separating zirconium into metallic high-level waste forms and to support development of a process for decontamination of zircaloy hulls to enable their disposal as low- and intermediate-level waste. Modeling work includes extension of a 3D model previously developed by Seoul National University for uranium electrorefining by adding the ability to predict zirconium behavior. Experimental validation activities include tests for recovery of zirconium from molten salt solutions and aqueous tests using surrogate materials. *This is a summary of the FY 2013 progress for I-NERI project # 2010-001-K provided to the I-NERI office.

  19. An Investigation into Geography Teachers' Use of Current Events in Geography Classes

    Science.gov (United States)

    Degirmenci, Yavuz; Ilter, Ilhan

    2017-01-01

    This study aimed to investigate the extent to which geography teachers use current events within the context of their geography instruction, their sources of information about current events, the methods and techniques they adopt while using current events in their teaching and the skills and values they expect their students to develop. The…

  20. Experimental Investigations on Conventional and Semi-Adiabatic Diesel Engine Using Simarouba Biodiesel as Fuel

    Science.gov (United States)

    Ravi, M. U.; Reddy, C. P.; Ravindranath, K.

    2013-04-01

    In view of fast depletion of fossil fuels and the rapid rate at which the fuel consumption is taking place all over the world, scientists are searching for alternate fuels for maintaining the growth industrially and economically. Hence search for alternate fuel(s) has become imminent. Out of the limited options for internal combustion engines, the bio diesel fuel appears to be the best. Many advanced countries are implementing several biodiesel initiatives and developmental programmes in order to become self sufficient and reduce the import bills. Biodiesel is biodegradable and renewable fuel with the potential to enhance the performance and reduce engine exhaust emissions. This is due to ready usage of existing diesel engines, fuel distribution pattern, reduced emission profiles, and eco-friendly properties of biodiesel. Simarouba biodiesel (SBD), the methyl ester of Simarouba oil is one such alternative fuel which can be used as substitute to conventional petro-diesel. The present work involves experimental investigation on the use of SBD blends as fuel in conventional diesel engine and semi-adiabatic diesel engine. The oil was triple filtered to eliminate particulate matter and then transesterified to obtain biodiesel. The project envisaged aims at conducting analysis of diesel with SBD blends (10, 20, 30 and 40 %) in conventional engine and semi-adiabatic engine. Also it was decided to vary the injection pressure (180, 190 and 200 bar) and observe its effect on performance and also suggest better value of injection pressure. The engine was made semi adiabatic by coating the piston crown with partially stabilized zirconia (PSZ). Kirloskar AV I make (3.67 kW) vertical, single cylinder, water cooled diesel engine coupled to an eddy current dynamometer with suitable measuring instrumentation/accessories used for the study. Experiments were initially carried out using pure diesel fuel to provide base line data. The test results were compared based on the performance

  1. Results from Nevada Nuclear Waste Storage Investigations (NNWSI) Series 3 spent fuel dissolution tests

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, C.N.

    1990-06-01

    The dissolution and radionuclide release behavior of spent fuel in groundwater is being studied by the Yucca Mountain Project (YMP), formerly the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. Specimens prepared from pressurized water reactor fuel rod segments were tested in sealed stainless steel vessels in Nevada Test Site J-13 well water at 85{degree}C and 25{degree}C. The test matrix included three specimens of bare-fuel particles plus cladding hulls, two fuel rod segments with artificially defected cladding and water-tight end fittings, and an undefected fuel rod section with watertight end fittings. Periodic solution samples were taken during test cycles with the sample volumes replenished with fresh J-13 water. Test cycles were periodically terminated and the specimens restarted in fresh J-13 water. The specimens were run for three cycles for a total test duration of 15 months. 22 refs., 32 figs., 26 tabs.

  2. Preliminary Investigation of Candidate Materials for Use in Accident Resistant Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Jason M. Harp; Paul A. Lessing; Blair H. Park; Jakeob Maupin

    2013-09-01

    As part of a Collaborative Research and Development Agreement (CRADA) with industry, Idaho National Laboratory (INL) is investigating several options for accident resistant uranium compounds including silicides, and nitrides for use in future light water reactor (LWR) fuels. This work is part of a larger effort to create accident tolerant fuel forms where changes to the fuel pellets, cladding, and cladding treatment are considered. The goal fuel form should have a resistance to water corrosion comparable to UO2, have an equal to or larger thermal conductivity than uranium dioxide, a melting temperature that allows the material to stay solid under power reactor conditions, and a uranium loading that maintains or improves current LWR power densities. During the course of this research, fuel fabricated at INL will be characterized, irradiated at the INL Advanced Test Reactor, and examined after irradiation at INL facilities to help inform industrial partners on candidate technologies.

  3. Development of a model to predict fission product behaviour in spherical fuel elements during water ingress events

    Energy Technology Data Exchange (ETDEWEB)

    Merwe, J.J. van der [PBMR, PO Box 9396, Centurion 0046 (South Africa)]. E-mail: hanno.vdmerwe@pbmr.co.za; Coetzee, P.P. [Randse Afrikaans University, PO Box 524, Auckland Park 2006 (South Africa)

    2007-01-15

    At PBMR gaseous fission product releases from spherical fuel elements under normal conditions are calculated by the code NOBLEG. The ability of NOBLEG to calculate noble gas and halogen release under oxidizing conditions during water ingress was developed. Observations made during the water vapour injection tests performed during the irradiation experiment HFR-K6, were used to determine simple relations that can be used to predict gaseous fission product release from spherical fuel elements under oxidizing conditions caused by small water ingress events, for PBMR operational temperatures. A new model was proposed to explain peculiarities observed during the water injection tests.

  4. Investigation on the effect of diaphragm on the combustion characteristics of solid-fuel ramjet

    Science.gov (United States)

    Gong, Lunkun; Chen, Xiong; Yang, Haitao; Li, Weixuan; Zhou, Changsheng

    2017-10-01

    The flow field characteristics and the regression rate distribution of solid-fuel ramjet with three-hole diaphragm were investigated by numerical and experimental methods. The experimental data were obtained by burning high-density polyethylene using a connected-pipe facility to validate the numerical model and analyze the combustion efficiency of the solid-fuel ramjet. The three-dimensional code developed in the present study adopted three-order MUSCL and central difference schemes, AUSMPW + flux vector splitting method, and second-order moment turbulence-chemistry model, together with k-ω shear stress transport (SST) turbulence model. The solid fuel surface temperature was calculated with fluid-solid heat coupling method. The numerical results show that strong circumferential flow exists in the region upstream of the diaphragm. The diaphragm can enhance the regression rate of the solid fuel in the region downstream of the diaphragm significantly, which mainly results from the increase of turbulent viscosity. As the diaphragm port area decreases, the regression rate of the solid fuel downstream of the diaphragm increases. The diaphragm can result in more sufficient mixing between the incoming air and fuel pyrolysis gases, while inevitably producing some pressure loss. The experimental results indicate that the effect of the diaphragm on the combustion efficiency of hydrocarbon fuels is slightly negative. It is conjectured that the diaphragm may have some positive effects on the combustion efficiency of the solid fuel with metal particles.

  5. Experimental investigation and modeling of an aircraft Otto engine operating with gasoline and heavier fuels

    Science.gov (United States)

    Saldivar Olague, Jose

    A Continental "O-200" aircraft Otto-cycle engine has been modified to burn diesel fuel. Algebraic models of the different processes of the cycle were developed from basic principles applied to a real engine, and utilized in an algorithm for the simulation of engine performance. The simulation provides a means to investigate the performance of the modified version of the Continental engine for a wide range of operating parameters. The main goals of this study are to increase the range of a particular aircraft by reducing the specific fuel consumption of the engine, and to show that such an engine can burn heavier fuels (such as diesel, kerosene, and jet fuel) instead of gasoline. Such heavier fuels are much less flammable during handling operations making them safer than aviation gasoline and very attractive for use in flight operations from naval vessels. The cycle uses an electric spark to ignite the heavier fuel at low to moderate compression ratios, The stratified charge combustion process is utilized in a pre-chamber where the spray injection of the fuel occurs at a moderate pressure of 1200 psi (8.3 MPa). One advantage of fuel injection into the combustion chamber instead of into the intake port, is that the air-to-fuel ratio can be widely varied---in contrast to the narrower limits of the premixed combustion case used in gasoline engines---in order to obtain very lean combustion. Another benefit is that higher compression ratios can be attained in the modified cycle with heavier fuels. The combination of injection into the chamber for lean combustion, and higher compression ratios allow to limit the peak pressure in the cylinder, and to avoid engine damage. Such high-compression ratios are characteristic of Diesel engines and lead to increase in thermal efficiency without pre-ignition problems. In this experimental investigation, operations with diesel fuel have shown that considerable improvements in the fuel efficiency are possible. The results of

  6. Investigation of tissue-specific human orthologous alternative splice events in pig

    DEFF Research Database (Denmark)

    Hillig, Ann-Britt Nygaard; Jørgensen, Claus Bøttcher; Salicio, Susanna Cirera

    2010-01-01

    investigated alternative splice events detected in humans, in orthologous pig genes. A total of 17 genes with predicted exon skipping events were selected for further studies. The splice events for the selected genes were experimentally verified using real-time quantitative PCR analysis (qPCR) with splice......Alternative splicing of pre-mRNA can contribute to differences between tissues or cells either by regulating gene expression or creating proteins with various functions encoded by one gene. The number of investigated alternative splice events in pig has so far been limited. In this study we have...

  7. Evidence of fuels management and fire weather influencing fire severity in an extreme fire event

    Science.gov (United States)

    Jamie M. Lydersen; Brandon M. Collins; Matthew L. Brooks; John R. Matchett; Kristen L. Shive; Nicholas A. Povak; Van R. Kane; Douglas F. Smith

    2017-01-01

    Following changes in vegetation structure and pattern, along with a changing climate, large wildfire incidence has increased in forests throughout the western U.S. Given this increase there is great interest in whether fuels treatments and previous wildfire can alter fire severity patterns in large wildfires. We assessed the relative influence of previous fuels...

  8. Numerical investigation of the heterogeneous combustion processes of solid fuels

    OpenAIRE

    Alganash, Blaid; Paul, M. C.; Watson, Ian.A.

    2015-01-01

    Two-phase computational modelling based on the Euler–Euler was developed to investigate the heterogeneous combustion processes of biomass, in the solid carbon phase, inside a newly designed combustion chamber (Model 1). A transient simulation was carried out for a small amount of carbon powder situated in a cup which was located at the centre of the combustion chamber. A heat source was provided to initiate the combustion with the air supplied by three injection nozzles. The results show that...

  9. Investigation of Bio-Diesel Fueled Engines under Low-Temperature Combustion Strategies

    Energy Technology Data Exchange (ETDEWEB)

    Chia-fon F. Lee; Alan C. Hansen

    2010-09-30

    In accordance with meeting DOE technical targets this research was aimed at developing and optimizing new fuel injection technologies and strategies for the combustion of clean burning renewable fuels in diesel engines. In addition a simultaneous minimum 20% improvement in fuel economy was targeted with the aid of this novel advanced combustion system. Biodiesel and other renewable fuels have unique properties that can be leveraged to reduce emissions and increase engine efficiency. This research is an investigation into the combustion characteristics of biodiesel and its impacts on the performance of a Low Temperature Combustion (LTC) engine, which is a novel engine configuration that incorporates technologies and strategies for simultaneously reducing NOx and particulate emissions while increasing engine efficiency. Generating fundamental knowledge about the properties of biodiesel and blends with petroleum-derived diesel and their impact on in-cylinder fuel atomization and combustion processes was an important initial step to being able to optimize fuel injection strategies as well as introduce new technologies. With the benefit of this knowledge experiments were performed on both optical and metal LTC engines in which combustion and emissions could be observed and measured under realistic conditions. With the aid these experiments and detailed combustion models strategies were identified and applied in order to improve fuel economy and simultaneously reduce emissions.

  10. Investigating the dynamics of a direct parallel combination of supercapacitors and polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Papra, M.; Buechi, F.N.; Koetz, R. [Electrochemistry Laboratory, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2010-10-15

    Hydrogen fuelled vehicles with a fuel cell based powertrain are considered to contribute to sustainable mobility by reducing CO{sub 2} emissions from road transport. In such vehicles the fuel cell system is typically hybridised with an energy storage device such as a battery or a supercapacitor (SC) to allow for recovering braking energy and assist the fuel cell system for peak power. The direct parallel combination of a polymer electrolyte fuel cell (PEFC) and a SC without any control electronics is investigated in the present study. It is demonstrated that the combination enhances the dynamics of the PEFC significantly during load changes. However, due to the lack of a power electronic interface the SC cannot be utilised to its optimum capacity. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  11. Experimental Investigations on the Effects of Cerium Oxide Nanoparticle Fuel Additives on Biodiesel

    Directory of Open Access Journals (Sweden)

    V. Sajith

    2010-01-01

    Full Text Available This paper reports the results of experimental investigations on the influence of the addition of cerium oxide in the nanoparticle form on the major physicochemical properties and the performance of biodiesel. The physicochemical properties of the base fuel and the modified fuel formed by dispersing the catalyst nanoparticles by ultrasonic agitation are measured using ASTM standard test methods. The effects of the additive nanoparticles on the individual fuel properties, the engine performance, and emissions are studied, and the dosing level of the additive is optimized. Comparisons of the performance of the fuel with and without the additive are also presented. The flash point and the viscosity of biodiesel were found to increase with the inclusion of the cerium oxide nanoparticles. The emission levels of hydrocarbon and NOx are appreciably reduced with the addition of cerium oxide nanoparticles.

  12. Summary of Off-Normal Events in US Fuel Cycle Facilities for AFCI Applications

    Energy Technology Data Exchange (ETDEWEB)

    L. C. Cadwallader; S. J. Piet; S. O. Sheetz; D. H. McGuire; W. B. Boore

    2005-09-01

    This report is a collection and review of system operation and failure experiences for facilities comprising the fission reactor fuel cycle, with the exception of reactor operations. This report includes mines, mills, conversion plants, enrichment plants, fuel fabrication plants, transportation of fuel materials between these centers, and waste storage facilities. Some of the facilities discussed are no longer operating; others continue to produce fuel for the commercial fission power plant industry. Some of the facilities discussed have been part of the military’s nuclear effort; these are included when the processes used are similar to those used for commercial nuclear power. When reading compilations of incidents and accidents, after repeated entries it is natural to form an opinion that there exists nothing but accidents. For this reason, production or throughput values are described when available. These adverse operating experiences are compiled to support the design and decisions needed for the Advanced Fuel Cycle Initiative (AFCI). The AFCI is to weigh options for a new fission reactor fuel cycle that is efficient, safe, and productive for US energy security.

  13. FUNDAMENTAL INVESTIGATION OF FUEL TRANSFORMATIONS IN PULVERIZED COAL COMBUSTION AND GASIFICATION TECHNOLOGIES

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Joseph Calo; Thomas H. Fletcher; Alan Sayre

    2005-04-29

    The goal of this project was to carry out the necessary experiments and analyses to extend current capabilities for modeling fuel transformations to the new conditions anticipated in next-generation coal-based, fuel-flexible combustion and gasification processes. This multi-organization, multi-investigator project has produced data, correlations, and submodels that extend present capabilities in pressure, temperature, and fuel type. The combined experimental and theoretical/computational results are documented in detail in Chapters 1-8 of this report, with Chapter 9 serving as a brief summary of the main conclusions. Chapters 1-3 deal with the effect of elevated pressure on devolatilization, char formation, and char properties. Chapters 4 and 5 deal with advanced combustion kinetic models needed to cover the extended ranges of pressure and temperature expected in next-generation furnaces. Chapter 6 deals with the extension of kinetic data to a variety of alternative solid fuels. Chapter 7 focuses on the kinetics of gasification (rather than combustion) at elevated pressure. Finally, Chapter 8 describes the integration, testing, and use of new fuel transformation submodels into a comprehensive CFD framework. Overall, the effects of elevated pressure, temperature, heating rate, and alternative fuel use are all complex and much more work could be further undertaken in this area. Nevertheless, the current project with its new data, correlations, and computer models provides a much improved basis for model-based design of next generation systems operating under these new conditions.

  14. Test Plans for Investigating Molten Fuel Behavior in Coolant Channel during SFR Core Melting Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Suk, Soo Dong; Hahn, Doo Hee; Lee, Yong Bum

    2006-09-15

    The metal-fueled, sodium-cooled fast reactor system is expected to accommodate all credible malfunctions or accident initiators passively without damage to the core. However, the evaluation of the safety performance and the containment requirements for this system will most likely require consideration of postulated low-probability accident sequences that result in partial or whole core melting. For these sequences, some phenomenological uncertainties exist and experimental data are needed for modeling purposes. One such data need is concerned with the potential for freezing and plugging of molten metallic fuel in above-and below-core structures and possibly in inter subassembly spaces. The first basic data need is the properties for metallic fuel/steel mixtures such as liquidus/solidus and mobilization temperatures, as part of measurement of phenomenological data describing the relocation and freezing behavior of molten metallic fuel. Accordingly, plans for two different tests, one for determination of the liquidus/solidus temperature and another for determination of the mobilization temperature, are described in this report. Test plans are then described in the report for the investigations of the relocation and freezing behavior of molten metallic fuel in coolant channels, including possible chemical interactions of molten fuel with the channel steel structure.

  15. Investigation of very high burnup UO{sub 2} fuels in Light Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Cappia, Fabiola

    2017-03-27

    Historically, the average discharge burnup of Light Water Reactor (LWR) fuel has increased almost continuously. On one side, increase in the average discharge burnup is attractive because it contributes to decrease part of the fuel cycle costs. On the other side, it raises the practical problem of predicting the performance, longevity and properties of reactor fuel elements upon accumulation of irradiation damage and fission products both during in-reactor operation and after discharge. Performance of the fuel and structural components of the core is one of the critical areas on which the economic viability and public acceptance of nuclear energy production hinges. Along the pellet radius, the fuel matrix is subjected to extremely heterogeneous alteration and damage, as a result of temperature and burnup gradients. In particular, in the peripheral region of LWR UO{sub 2} fuel pellets, when the local burnup exceeds 50-70 GWd/tHM, a microstructural transformation starts to take place, as a consequence of enhanced accumulation of radiation damage, fission products and limited thermal recovery. The newly formed structure is commonly named High Burnup Structure (HBS). The HBS is characterised by three main features: (a) formation of submicrometric grains from the original grains, (b) depletion of fission gas from the fuel matrix, (c) steep increase in the porosity, which retains most of the gas depleted from the fuel matrix. The last two aspects rose significant attention because of the important impact of the fission gas behaviour on integral fuel performance. The porosity increase controls the gas-driven swelling, worsening the cladding loading once the fuel-cladding gap is closed. Another concern is that the large retention of fission gas within the HBS could lead to significant release at high burnups through the degradation of thermal conductivity or contribute to fuel pulverisation during accidental conditions. Need of more experimental investigations about the

  16. Effects of fuel Lewis number on localised forced ignition of turbulent homogeneous mixtures: A numerical investigation

    Directory of Open Access Journals (Sweden)

    Dipal Patel

    2016-09-01

    Full Text Available The influences of fuel Lewis number LeF (ranging from 0.8 to 1.2 on localised forced ignition and early stages of combustion of stoichiometric and fuel-lean homogeneous mixtures have been analysed using simple chemistry three-dimensional compressible direct numerical simulations for different values of root-mean-square velocity fluctuation and the energy deposition characteristics (i.e. characteristic width and the duration of energy deposition by the ignitor. The localised forced ignition is modelled using a source term in the energy transport equation, which deposits energy in a Gaussian manner from the centre of the ignitor over a stipulated period of time. The fuel Lewis number LeF has been found to have significant influences on the extent of burning of stoichiometric and fuel-lean homogeneous mixtures. It has been shown that the width of ignition energy deposition and the duration over which the ignition energy is deposited have significant influences on the success of ignition and subsequent flame propagation. An increase in the width of ignition energy deposition and the duration of energy deposition for a given amount of ignition energy have been found to have detrimental effects on the ignition event, which may ultimately lead to misfire. For a given value of u' (LeF, the rate of heat transfer from the hot gas kernel increases with increasing LeF (u', which in turn leads to a reduction in the extent of overall burning for both stoichiometric and fuel-lean homogeneous mixtures but the detrimental effects of high values of u' on localised forced ignition are particularly prevalent for fuel-lean mixtures. Detailed physical explanations have been provided for the observed LeF,u' and energy deposition characteristics effects.

  17. Investigation of the characteristics of a stacked direct borohydride fuel cell for portable applications

    Science.gov (United States)

    Kim, Cheolhwan; Kim, Kyu-Jung; Ha, Man Yeong

    To investigate the possibility of the portable application of a direct borohydride fuel cell (DBFC), weight reduction of the stack and high stacking of the cells are investigated for practical running conditions. For weight reduction, carbon graphite is adopted as the bipolar plate material even though it has disadvantages in tight stacking, which results in stacking loss from insufficient material strength. For high stacking, it is essential to have a uniform fuel distribution among cells and channels to maintain equal electric load on each cell. In particular, the design of the anode channel is important because active hydrogen generation causes non-uniformity in the fuel flow-field of the cells and channels. To reduce the disadvantages of stacking force margin and fuel maldistribution, an O-ring type-sealing system with an internal manifold and a parallel anode channel design is adopted, and the characteristics of a single and a five-cell fuel cell stack are analyzed. By adopting carbon graphite, the stack weight can be reduced by 4.2 times with 12% of performance degradation from the insufficient stacking force. When cells are stacked, the performance exceeds the single-cell performance because of the stack temperature increase from the reduction of the radiation area from the narrow stacking of cells.

  18. Investigation of Ruthenium Dissolution in Advanced Membrane Electrode Assemblies for Direct Methanol Based Fuel Cells Stacks

    Science.gov (United States)

    Valdez, T. I.; Firdosy, S.; Koel, B. E.; Narayanan, S. R.

    2005-01-01

    This viewgraph presentation gives a detailed review of the Direct Methanol Based Fuel Cell (DMFC) stack and investigates the Ruthenium that was found at the exit of the stack. The topics include: 1) Motivation; 2) Pathways for Cell Degradation; 3) Cell Duration Testing; 4) Duration Testing, MEA Analysis; and 5) Stack Degradation Analysis.

  19. An investigation of the influence of heating modes on ignition and pyrolysis of woody wildland fuel

    Science.gov (United States)

    B.L. Yashwanth; B. Shotorban; S. Mahalingam; D.R. Weise

    2015-01-01

    The ignition of woody wildland fuel modeled as a one-dimensional slab subject to various modes of heating was investigated using a general pyrolysis code, Gpyro. The heating mode was varied by applying different convective and/or radiative, time-dependent heat flux boundary conditions on one end of the slab while keeping the other end insulated. Dry wood properties...

  20. Bitumen/Water Emulsions as Fuels for High-Speed Ci Engines Preliminary Investigations

    DEFF Research Database (Denmark)

    Schramm, Jesper; Sigvardsen, R.; Forman, M.

    2003-01-01

    system - high content of heavy metals - high emissions of particulate matter and PAH This investigation deals with the problem of separation due to high shear stress in the injection system. It is shown that the viscosity of the injected fuel can be used to estimate whether the emulsion has separated...

  1. Dynamic modeling and experimental investigation of a high temperature PEM fuel cell stack

    DEFF Research Database (Denmark)

    Nguyen, Gia; Sahlin, Simon Lennart; Andreasen, Søren Juhl

    2016-01-01

    is investigated with simulated reformate gas. The dynamic response of the fuel cell stack was compared with a step change in current from 0.09 to 0.18 and back to 0.09 A/cm2 . This article shows that the dynamic model calculates the voltage at steady state well. The dynamic response for a change in current shows...

  2. Numerical investigation on the characteristics of two-phase flow in fuel assemblies with spacer grid

    Energy Technology Data Exchange (ETDEWEB)

    Chen, D.; Yang, Z.; Zhong, Y.; Xiao, Y.; Hu, L. [Chongqing Univ. (China). Key Lab. of Low-grade Energy Utilization Technologies and Systems

    2016-07-15

    In pressurized water reactors (PWRs), the spacer grids of the fuel assembly has significant impact on the thermal-hydraulic performance of the fuel assembly. Particularly, the spacer grids with the mixing vanes can dramatically enhance the secondary flow and have significant effect on the void distribution in the fuel assembly. In this paper, the CFD study has been carried out to analyze the effects of the spacer grid with the steel contacts, dimples and mixing vanes on the boiling two-phase flow characteristics, such as the two-phase flow field, the void distribution, and so on. Considered the influence of the boiling phase change on two-phase flow, a boiling model was proposed and applied in the CFD simulation by using the UDF (User Defined Function) method. Furthermore, in order to analyze the effects of the spacer grid with mixing vanes, the adiabatic (without boiling) two-phase flow has also been investigated as comparison with the boiling two-phase flow in the fuel assembly with spacer grids. The CFD simulation on two-phase flow in the fuel assembly with the proposed boiling model can predict the characteristics of two-phase flow better.

  3. Preliminary Investigation for Engine Performance by Using Tire-Derived Pyrolysis Oil-Diesel Blended Fuels

    Science.gov (United States)

    Rofiqul, Islam M.; Haniu, Hiroyuki; Alam, Beg R.; Takai, Kazunori

    In the first phase of the present study, the pyrolysis oil derived from light automotive tire waste has been characterized including fuel properties, elemental analyses, FT-IR, 1H-NMR, GC-MS and distillation. The studies on the oil show that it can be used as liquid fuel with a gross calorific value (GCV) of 42.00 MJ/kg and empirical formula of CH1.27O0.025N0.006. In the second phase of the investigation, the performance of a diesel engine was studied blending the pyrolysis oil with diesel fuel in different ratios. The experimental results show that the bsfc of pyrolysis oil-diesel blended fuels slightly increases and hence the brake thermal efficiency decreases compared to those of neat diesel. The pyrolysis oil-diesel blends show lower carbon monoxide (CO) emission but higher oxides of nitrogen (NOx) emissions than those of neat diesel. However, NOx emissions with pyrolysis oil-diesel blended fuels reduced when EGR was applied.

  4. An event portfolio in rural development: an ethnographic investigation of a community's use of sport and cultural events

    OpenAIRE

    Ziakas, V

    2007-01-01

    Sport events have been studied predominantly in isolation from other genres, as single events that have economic or social impacts mainly for urban communities. Yet, the apparent economic and social value of recurring small-scale sport and cultural events in rural communities call for strategic and integrated planning in policies for rural development. This requires that instead of assessing the economic or social benefits of a certain event, a series of interrelated events that comprise a ho...

  5. Oxidation investigation of cladding specimens for regular and accident tolerant fuel rods under LOCA conditions

    Science.gov (United States)

    Bazyuk, S. S.; Deryabin, I. A.; Kiselev, D. S.; Kuzma-Kichta, Yu A.; Mokrushin, A. A.; Parshin, N. Ya; Popov, E. B.; Soldatkin, D. M.

    2017-11-01

    The high-temperature oxidation tests were carried out for the regular fuel rod claddings specimens made of sponge-based zirconium alloy (E110G) and for the accident tolerant fuel (ATF) ones – pure vacuum melted molybdenum (VCPM) and niobium alloy (Nb-1%Zr). The tests were carried out under the ambient pressure p ∼ 0.1 MPa in pure water steam. The experimental data on the oxidation characteristics were obtained for E110G specimens in the temperature range T = 1100 ‑ 1500 °C, that for VCPM and Nb-1%Zr are investigated under extended temperature-duration range (more than 1 hour). The thermal effects of molybdenum (QSMR) and niobium (QSNR) interactions with steam were defined and the derived oxidation rate constants for refractory metals were compared with the known ones. Based on the computations performed with PARAM-TG code the high-temperature oxidation characteristics of model fuel assemblies of large-scale facilities under LOCA conditions with regular and ATF claddings were compared. It was shown that Zr-steam interaction of fuel rod cladding (QSZR) is more intensive compared with VCPM and Nb-1%Zr ones under investigated conditions.

  6. Experimental investigation on cyclic variability, engine performance and exhaust emissions in a diesel engine using alcohol-diesel fuel blends

    Directory of Open Access Journals (Sweden)

    Gurgen Samet

    2017-01-01

    Full Text Available This paper investigates the impacts of using n-butanol-diesel fuel and ethanol-diesel fuel blends on engine performance, exhaust emission, and cycle-by-cycle variation in a Diesel engine. The engine was operated at two different engine speed and full load condition with pure diesel fuel, 5% and 10% (by vol. ethanol and n-butanol fuel blends. The coefficient of variation of indicated mean effective pressure was used to evaluate the cyclic variability of n-butanol-diesel fuel and ethanol-diesel fuel blends. The results obtained in this study showed that effective efficiency and brake specific fuel consumption generally increased with the use of the n-butanol-diesel fuel or ethanol-diesel fuel blends with respect to that of the neat diesel fuel. The addition of ethanol or n-butanol to diesel fuel caused a decrement in CO and NOx emissions. Also, the results indicated that cycle-by-cycle variation has an increasing trend with the increase of alcohol-diesel blending ratio for all engine speed. An increase in cyclic variability of alcohol-diesel fuel blends at low engine speed is higher than that of high engine speed.

  7. Investigation of polymer electrolyte membrane fuel cell internal behaviour during long term operation and its use in prognostics

    Science.gov (United States)

    Mao, Lei; Jackson, Lisa; Jackson, Tom

    2017-09-01

    This paper investigates the polymer electrolyte membrane (PEM) fuel cell internal behaviour variation at different operating condition, with characterization test data taken at predefined inspection times, and uses the determined internal behaviour evolution to predict the future PEM fuel cell performance. For this purpose, a PEM fuel cell behaviour model is used, which can be related to various fuel cell losses. By matching the model to the collected polarization curves from the PEM fuel cell system, the variation of fuel cell internal behaviour can be obtained through the determined model parameters. From the results, the source of PEM fuel cell degradation during its lifetime at different conditions can be better understood. Moreover, with determined fuel cell internal behaviour, the future fuel cell performance can be obtained by predicting the future model parameters. By comparing with prognostic results using adaptive neuro fuzzy inference system (ANFIS), the proposed prognostic analysis can provide better predictions for PEM fuel cell performance at dynamic condition, and with the understanding of variation in PEM fuel cell internal behaviour, mitigation strategies can be designed to extend the fuel cell performance.

  8. Investigation and demonstration of a rich combustor cold-start device for alcohol-fueled engines

    Energy Technology Data Exchange (ETDEWEB)

    Hodgson, J W; Irick, D K [Univ. of Tennessee, Knoxville, TN (United States)

    1998-04-01

    The authors have completed a study in which they investigated the use of a rich combustor to aid in cold starting spark-ignition engines fueled with either neat ethanol or neat methanol. The rich combustor burns the alcohol fuel outside the engine under fuel-rich conditions to produce a combustible product stream that is fed to the engine for cold starting. The rich combustor approach significantly extends the cold starting capability of alcohol-fueled engines. A design tool was developed that simulates the operation of the combustor and couples it to an engine/vehicle model. This tool allows the user to determine the fuel requirements of the rich combustor as the vehicle executes a given driving mission. The design tool was used to design and fabricate a rich combustor for use on a 2.8 L automotive engine. The system was tested using a unique cold room that allows the engine to be coupled to an electric dynamometer. The engine was fitted with an aftermarket engine control system that permitted the fuel flow to the rich combustor to be programmed as a function of engine speed and intake manifold pressure. Testing indicated that reliable cold starts were achieved on both neat methanol and neat ethanol at temperatures as low as {minus}20 C. Although starts were experienced at temperatures as low as {minus}30 C, these were erratic. They believe that an important factor at the very low temperatures is the balance between the high mechanical friction of the engine and the low energy density of the combustible mixture fed to the engine from the rich combustor.

  9. An experimental investigation of solid oxide fuel cell performance at variable operating conditions

    Directory of Open Access Journals (Sweden)

    Tikiz Ismet

    2016-01-01

    Full Text Available Cell temperature and selection of the reactant gases are crucial parameters for the design and optimization of fuel cell performance. In this study, effect of operating conditions on the performance of Solid Oxide Fuel (SOFC has been investigated. Application of Response Surface Methodology (RSM was applied to optimize operations conditions in SOFC. For this purpose, an experimental set up for testing of SOFC has been established to investigate the effect of Hydrogen, Oxygen, Nitrogen flow rates and cell temperature parameters on cell performance. Hydrogen flow rate, oxygen flow rate, nitrogen flow rate and cell temperature were the main parameters considered and they were varied between 0.25 and 1 L/min, 0.5 and 1 L/min, 0 and 1 L/min and 700-800 oC in the analyses respectively. The maximum power density was found as 0.572 W/cm2 in the experiments.

  10. Events

    Directory of Open Access Journals (Sweden)

    Igor V. Karyakin

    2016-02-01

    Full Text Available The 9th ARRCN Symposium 2015 was held during 21st–25th October 2015 at the Novotel Hotel, Chumphon, Thailand, one of the most favored travel destinations in Asia. The 10th ARRCN Symposium 2017 will be held during October 2017 in the Davao, Philippines. International Symposium on the Montagu's Harrier (Circus pygargus «The Montagu's Harrier in Europe. Status. Threats. Protection», organized by the environmental organization «Landesbund für Vogelschutz in Bayern e.V.» (LBV was held on November 20-22, 2015 in Germany. The location of this event was the city of Wurzburg in Bavaria.

  11. Numerical investigation of injector geometry effects on fuel stratification in a GCI engine

    KAUST Repository

    Atef, Nour

    2017-11-24

    Injectors play an important role in direct injection (DI) gasoline compression ignition (GCI) engines by affecting the in-cylinder mixture formation and stratification, which in turn impacts combustion and emissions. In this work, the effects of two different injector geometries, a 7-hole solid-cone injector and an outwardly opening hollow-cone injector, on fuel mixture stratification in a GCI engine were investigated by computational simulations. Three fuels with similar autoignition kinetics, but with different physical properties, were studied to isolate the effect of the combustion chemistry on combustion phasing. In addition, start of injection (SOI) sweeps relevant to low-load engine operating conditions were performed. The results show that physical properties of the fuel do not have significant influence when using a hollow-cone injector. Richer mixtures were observed at all the studied SOI (−40 to −14 CAD aTDC) cases, which can be attributed to the nature of the hollow cone spray. At later SOIs (−18 and −14 CAD aTDC), the richer mixtures are accompanied by lower mean in-cylinder temperature due to the charge cooling effect, which surpasses the equivalence ratio effect. The effect of fuel physical properties on combustion phasing was evident in multi-hole injection cases, which can be attributed to the differences in mixture stratification and equivalence ratio distribution at the time of ignition.

  12. Experimental investigation of an improved exhaust recovery system for liquid petroleum gas fueled spark ignition engine

    Directory of Open Access Journals (Sweden)

    Gürbüz Habib

    2015-01-01

    Full Text Available In this study, we have investigated the recovery of energy lost as waste heat from exhaust gas and engine coolant, using an improved thermoelectric generator (TEG in a LPG fueled SI engine. For this purpose, we have designed and manufactured a 5-layer heat exchanger from aluminum sheet. Electrical energy generated by the TEG was then used to produce hydrogen in a PEM water electrolyzer. The experiment was conducted at a stoichiometric mixture ratio, 1/2 throttle position and six different engine speeds at 1800-4000 rpm. The results of this study show that the configuration of 5-layer counterflow produce a higher TEG output power than 5-layer parallel flow and 3-layer counterflow. The TEG produced a maximum power of 63.18 W when used in a 5-layer counter flow configuration. This resulted in an improved engine performance, reduced exhaust emission as well as an increased engine speed when LPG fueled SI engine is enriched with hydrogen produced by the PEM electrolyser supported by TEG. Also, the need to use an extra evaporator for the LPG fueled SI engine is eliminated as LPG heat exchangers are added to the fuel line. It can be concluded that an improved exhaust recovery system for automobiles can be developed by incorporating a PEM electrolyser, however at the expense of increasing costs.

  13. Investigation of the Hydrodynamics of Sweep Blade in Hi-Speed Axial Fuel Pump Impeller

    Directory of Open Access Journals (Sweden)

    Ran Tao

    2013-01-01

    Full Text Available Fuel pump is a crucial component in aircraft engine ignition system. For the hi-speed axial fuel pumps, rotating stall triggers vortex and affects the operation stability and security. Sweep blade is widely used to solve the stability problems in aerodynamics field. Investigation on the hydrodynamics was conducted in this study. Based on the typical straight blade pump, positive and negative sweep blade pumps were modeled. With the large eddy simulation method, CFD simulations were conducted to calculate and analyze the flow characteristics in the pump models. To verify the simulation, experiments were also launched on the hydraulic test rig. Results show that the vortex occurs at the suction surface of blade and gathers near the blade tip region. Positive sweep blade is effective to reduce the hydraulic losses by driving the stalled fluid into the mid-part of blade. By applying the positive sweep blade on the axial fuel pump, the instability operating region will be diminished. Adopting sweep blade provides an effective means for stability and security of axial fuel pumps.

  14. Investigations of large fast core characteristics with MOX fuel at BFS facility with limited amount of Pu

    Energy Technology Data Exchange (ETDEWEB)

    Belov, S.P.; Kazanskii, Yu.A.; Kotchetkov, A.L.; Matveenko, I.P. [IPPE, Obninsk (Russian Federation)

    1996-09-01

    Theoretical investigations showed, that it is possible to investigate dimensional depended neutron characteristics of reactor with plutonium fuel in experiments without or with limited amount of plutonium. Such conclusion was proved in critical experiments at the BFS facility. (author)

  15. Numerical investigation of the ignition of dilute fuel sprays including detailed chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gutheil, E. (Univ. Stuttgart (Germany))

    1993-05-01

    One-dimensional unsteady numerical calculations have been performed to study the ignition of dilute fuel sprays. Recent investigations in this field employ global kinetic rate expressions to model the chemical reactions occurring in the gas phase. In the present paper a detailed kinetic mechanism is employed to describe the ignition process of dilute methanol sprays in air, the mechanism for methanol comprises 23 species and 168 elementary reactions. The present investigation accounts for unsteady droplet heating and vaporization using a distillation-limit model; temperature dependence of liquid phase properties is included. Effects of varying parameters such as initial gas temperature, initial fuel-vapor concentration, pressure, droplet size in both monodisperse and bidisperse sprays as well as equivalence ratio on both ignition-delay time and on spray lifetime are investigated. It is shown that there is a minimum ignition-delay time in dependence of both equivalence ratio and of initial droplet size for various conditions. Ignition-delay time of a bidisperse spray is dominated by the characteristics of the smaller droplets. There is a two-stage heating for small droplets caused by gas-phase characteristics. Fuel-vapor accumulation leads to delayed ignition and to higher gas temperatures for small droplets. The results of the calculations give profiles of radical concentrations such as OH as well as concentration of pollutants.

  16. Analytical Investigation and Improvement of Performance of a Proton Exchange Membrane (Pem) Fuel Cell in Mobile Applications

    OpenAIRE

    Khazaee I.

    2015-01-01

    In this study, the performance of a proton exchange membrane fuel cell in mobile applications is investigated analytically. At present the main use and advantages of fuel cells impact particularly strongly on mobile applications such as vehicles, mobile computers and mobile telephones. Some external parameters such as the cell temperature (Tcell ) , operating pressure of gases (P) and air stoichiometry (λair ) affect the performance and voltage losses in the PEM fuel cell. Because of the exis...

  17. Investigating the Source Mechanisms of Deflation-Inflation Events at Kilauea Volcano, Hawai`i

    Science.gov (United States)

    Johnson, J. H.; Anderson, K. R.; Poland, M. P.; Miklius, A.

    2012-12-01

    inter-related mechanisms have been suggested to explain the DI events: (1) blockage and subsequent clearing of the transport pathway that feeds the shallow summit magma system and conduit to Pu`u `O`o, and (2) convective overturns caused by replacement of degassed magma with gas-rich magma. Using a simple kinematic forward model, we invert deformation data from more than 400 DI events to estimate the location and volume change of the shallow summit source generating the ground tilt, and look for changes associated with the evolution of eruptive behaviour at Kilauea. More insight into the DI events can be gained by developing a physics-based model capable of linking magmatic processes with the temporal evolution of individual DI events. We will construct multiphysics finite element models (FEMs) to simulate deformation caused by the two proposed mechanisms to link the observations to the physical processes that drive DI events. The FEMs allow us to investigate complicated model configurations that account for 3D geometric configurations, distributions of rheologic properties, and multiple deformation sources. Crucially, the models also allow for temporal variation of fluid flow and subsurface pressurization, which will provide insights into the unique patterns of tilt observed at Kilauea.

  18. Experimental investigation of solid oxide fuel cells using biomass gasification producer gases

    Energy Technology Data Exchange (ETDEWEB)

    Norheim, Arnstein

    2005-07-01

    The main objective of this thesis is theoretical and experimental investigations related to utilisation of biomass gasification producer gases as fuel for Solid Oxide Fuel Cells (SOFC). Initial fundamental steps towards a future system of combined heat and power production based on biomass gasification and SOFC are performed and include: 1) Theoretical modeling of the composition of biomass gasification producer gases. 2) Experimental investigation of SOFC performance using biomass gasification producer gas as fuel. 3) Experimental investigation of SOFC performance using biomass gasification producer gas containing high sulphur concentration. The modeling of the composition of gasifier producer gas was performed using the program FactSage. The main objective was to investigate the amount and speciation of trace species in the producer gases as several parameters were varied. Thus, the composition at thermodynamic equilibrium of sulphur, chlorine, potassium, sodium and compounds of these were established. This was done for varying content of the trace species in the biomass material at different temperatures and fuel utilisation i.e. varying oxygen content in the producer gas. The temperature interval investigated was in the range of normal SOFC operation. It was found that sulphur is expected to be found as H2S irrespective of temperature and amount of sulphur. Only at very high fuel utilisation some S02 is formed. Important potassium containing compounds in the gas are gaseous KOH and K. When chlorine is present, the amount of KOH and K will decrease due to the formation of KCI. The level of sodium investigated here was low, but some Na, NaOH and NaCl is expected to be formed. Below a certain temperature, condensation of alkali rich carbonates may occur. The temperature at which condensation begins is mainly depending on the amount of potassium present; the condensation temperature increases with increasing potassium content. In the first experimental work

  19. Hydrides reorientation investigation of high burn-up PWR fuel cladding

    Science.gov (United States)

    Valance, Stéphane; Bertsch, Johannes

    2015-09-01

    The direction of formation of hydride in fuel cladding tube is a major issue for the assessment of the cladding remaining ductility after service. This behavior is quite well known for fresh material, but few results exist for irradiated material. The reorientation behavior of a Zircaloy-4 fuel cladding (AREVA duplex DX-D4) at a burn-up of around 72 GWd t-1 is investigated here. The increase of the fraction of reoriented hydrides through repeated thermo-mechanical loading is inspected; as well, the possibility to recover a state with a minimized quantity of reoriented hydrides is tested using pure thermal loading cycles. The study is completed by a qualitative assessment of the hydrogen density in the duplex layer, where a dependence of the hydrides density on the hoop stress state is observed.

  20. The effect of fuel pyrolysis on the coal particle combustion: An analytical investigation

    Directory of Open Access Journals (Sweden)

    Baghsheikhi Mostafa

    2016-01-01

    Full Text Available The aim of this work is to analytically investigate the symmetrical combustion of an isolated coal particle with the fuel pyrolysis effect. The modelling concept of coal particles is similar to that of the liquid droplet combustion but in the case of coal devolatilization, the particles do not shrink like droplet does due to evaporation of liquid fuel. The rate of devolatilization of volatiles can be calculated using the equation that is similar to Arrhenius equation. This model is based on an assumption of combined quasi-steady and transient behaviour of the process and especially focuses on predicting the variations of temperature profile, radius of pyrolysis and transfer number. It is revealed that the entrance of pyrolysis effect into the governing equations leads to the reduction in the film radius and consequently a reduction in the stand-off ratio and transfer number.

  1. High-throughput investigation of catalysts for JP-8 fuel cracking to liquefied petroleum gas.

    Science.gov (United States)

    Bedenbaugh, John E; Kim, Sungtak; Sasmaz, Erdem; Lauterbach, Jochen

    2013-09-09

    Portable power technologies for military applications necessitate the production of fuels similar to LPG from existing feedstocks. Catalytic cracking of military jet fuel to form a mixture of C₂-C₄ hydrocarbons was investigated using high-throughput experimentation. Cracking experiments were performed in a gas-phase, 16-sample high-throughput reactor. Zeolite ZSM-5 catalysts with low Si/Al ratios (≤25) demonstrated the highest production of C₂-C₄ hydrocarbons at moderate reaction temperatures (623-823 K). ZSM-5 catalysts were optimized for JP-8 cracking activity to LPG through varying reaction temperature and framework Si/Al ratio. The reducing atmosphere required during catalytic cracking resulted in coking of the catalyst and a commensurate decrease in conversion rate. Rare earth metal promoters for ZSM-5 catalysts were screened to reduce coking deactivation rates, while noble metal promoters reduced onset temperatures for coke burnoff regeneration.

  2. Progress in on-going experimental and computational fluid dynamic investigations within a CANDU fuel channel

    Energy Technology Data Exchange (ETDEWEB)

    Piro, M.H.A., E-mail: markus.piro@cnl.ca [Fuel and Fuel Channel Safety Branch, Canadian Nuclear Laboratories, Station 88, Chalk River, ON, Canada 37831-6063 (Canada); Wassermann, F., E-mail: wassermann@csi.tu-darmstadt.de [Center of Smart Interfaces, Technische Universität Darmstadt, Darmstadt (Germany); Grundmann, S. [Center of Smart Interfaces, Technische Universität Darmstadt, Darmstadt (Germany); Leitch, B.W. [Fuel and Fuel Channel Safety Branch, Canadian Nuclear Laboratories, Station 88, Chalk River, ON, Canada 37831-6063 (Canada); Tropea, C. [Center of Smart Interfaces, Technische Universität Darmstadt, Darmstadt (Germany)

    2016-04-01

    The present work investigates the velocity field within a simplified CANDU fuel bundle with Computational Fluid Dynamic (CFD) simulations and Magnetic Resonance Velocimetry (MRV). MRV is a relatively new experimental method that is not prone to many limitations inherent to conventional fluid flow measurement techniques. Initial results of a simplified non-deformed bundle are presented as a proof-of-concept study, while simultaneously introducing the MRV technique to the nuclear thermal–hydraulics community. The CFD predictions are generally in good agreement with experimental results, both of which reveal complex turbulent behaviour, including rotation, swirl and vortex shedding. This work presents progress in a greater effort to understand the fluid behaviour through a deformed fuel bundle in the context of safety.

  3. Fuel consumption and fire emissions estimates using Fire Radiative Power, burned area and statistical modelling on the fire event scale

    Science.gov (United States)

    Ruecker, Gernot; Leimbach, David; Guenther, Felix; Barradas, Carol; Hoffmann, Anja

    2016-04-01

    Fire Radiative Power (FRP) retrieved by infrared sensors, such as flown on several polar orbiting and geostationary satellites, has been shown to be proportional to fuel consumption rates in vegetation fires, and hence the total radiative energy released by a fire (Fire Radiative Energy, FRE) is proportional to the total amount of biomass burned. However, due to the sparse temporal coverage of polar orbiting and the coarse spatial resolution of geostationary sensors, it is difficult to estimate fuel consumption for single fire events. Here we explore an approach for estimating FRE through temporal integration of MODIS FRP retrievals over MODIS-derived burned areas. Temporal integration is aided by statistical modelling to estimate missing observations using a generalized additive model (GAM) and taking advantage of additional information such as land cover and a global dataset of the Canadian Fire Weather Index (FWI), as well as diurnal and annual FRP fluctuation patterns. Based on results from study areas located in savannah regions of Southern and Eastern Africa and Brazil, we compare this method to estimates based on simple temporal integration of FRP retrievals over the fire lifetime, and estimate the potential variability of FRP integration results across a range of fire sizes. We compare FRE-based fuel consumption against a database of field experiments in similar landscapes. Results show that for larger fires, this method yields realistic estimates and is more robust when only a small number of observations is available than the simple temporal integration. Finally, we offer an outlook on the integration of data from other satellites, specifically FireBird, S-NPP VIIRS and Sentinel-3, as well as on using higher resolution burned area data sets derived from Landsat and similar sensors.

  4. Experimental Investigation of Bearing Slip in a Wind Turbine Gearbox During a Transient Grid Loss Event

    Energy Technology Data Exchange (ETDEWEB)

    Helsen, Jan; Guo, Yi; Keller, Jonathan; Guillaume, Patrick

    2016-12-01

    This work investigates the behaviour of the high speed stage of a wind turbine gearbox during a transient grid loss event. Dynamometer testing on a full scale wind turbine nacelle is used. A combination of external and internal gearbox measurements is analysed. Particular focus is on the characterization of the high speed shaft tapered roller bearing slip behaviour. This slipping behaviour is linked to dynamic events by many researchers and described as potential bearing failure initiator. However only limited full scale dynamic testing is documented. Strain gauge bridges in grooves along the circumference of the outer ring are used to characterize the bearing behaviour in detail. It is shown that during the transient event the high speed shaft experiences a combined torsional and bending deformation. These unfavourable loading conditions induce roller slip in the bearings during the torque reversals indicating the potential of the applied load case to go beyond the preload of the tapered roller bearing.

  5. Investigative Study to Determine Effects of Hydro-Treated Renewable JP-8 Jet Fuel Blend in Existing Fuels Infrastructure

    Science.gov (United States)

    2012-02-01

    Specification. Department of Defense. MIL-DTL-25988. (2006). Detail Specification: Rubber, Fluorosilicone Elastomer, Oil- and Fuel- Resistant, Sheets, Strips ...Oil-and-Fuel- Resistant, Sheets, Strips , Molded Parts, and Extruded Shapes. Retrieved from HIS on August 28, 2010 Society of Automotive Engineers...nitrogen and sulfur to bond with the excess hydrogen creating ammonia NH3 and hydrogen sulfide (H2S). The triglycerides are also reacted and broken

  6. Electrochemical investigation of mixed metal oxide nanocomposite electrode for low temperature solid oxide fuel cell

    Science.gov (United States)

    Abbas, Ghazanfar; Raza, Rizwan; Ashfaq Ahmad, M.; Ajmal Khan, M.; Jafar Hussain, M.; Ahmad, Mukhtar; Aziz, Hammad; Ahmad, Imran; Batool, Rida; Altaf, Faizah; Zhu, Bin

    2017-10-01

    Zinc-based nanostructured nickel (Ni) free metal oxide electrode material Zn0.60/Cu0.20Mn0.20 oxide (CMZO) was synthesized by solid state reaction and investigated for low temperature solid oxide fuel cell (LTSOFC) applications. The crystal structure and surface morphology of the synthesized electrode material were examined by XRD and SEM techniques respectively. The particle size of ZnO phase estimated by Scherer’s equation was 31.50 nm. The maximum electrical conductivity was found to be 12.567 S/cm and 5.846 S/cm in hydrogen and air atmosphere, respectively at 600∘C. The activation energy of the CMZO material was also calculated from the DC conductivity data using Arrhenius plots and it was found to be 0.060 and 0.075 eV in hydrogen and air atmosphere, respectively. The CMZO electrode-based fuel cell was tested using carbonated samarium doped ceria composite (NSDC) electrolyte. The three layers 13 mm in diameter and 1 mm thickness of the symmetric fuel cell were fabricated by dry pressing. The maximum power density of 728.86 mW/cm2 was measured at 550∘C.

  7. Experimental investigation on CRDI engine using butanol-biodiesel-diesel blends as fuel

    Science.gov (United States)

    Divakar Shetty, A. S.; Dineshkumar, L.; Koundinya, Sandeep; Mane, Swetha K.

    2017-07-01

    In this research work an experimental investigation of butanol-biodisel-diesel blends on combustion, performance and emission characteristics of a direct injection (DI) diesel engine is carried out. The blends are prepared at different proportions and fuel properties such as calorific value, viscosity, flash point and fire point, cloud point, pour point of butanol (B), biodiesel (B), diesel (D), biodiesel-diesel (BD) blends and butanol-biodiesel-diesel (BBD) blends are determined. The engine test is conducted at different speed and load. From the results obtained for fuel properties we can observe that the flash, fire and pour point, viscosity and density are decreasing by increasing the percentage of butanol in BBD blends. It is also observed that the performance parameters such as brake thermal efficiency (BTE) and exhaust gas temperature increases with increase in the proportion of butanol in BBD blend. However, the brake specific fuel consumption (BFSC) decreases with increase in the proportion of butanol in BBD blend. The increase of butanol in BBD blends also influence to increase on emission characteristic such as carbon monoxide (CO), hydrocarbon (HC) and oxides of nitrogen (NOx).

  8. Investigations into the interactions between sulfur and anodes for solid oxide fuel cells

    Science.gov (United States)

    Cheng, Zhe

    Solid oxide fuel cells (SOFCs) are electrochemical devices based on solid oxide electrolytes that convert chemical energy in fuels directly into electricity via electrode reactions. SOFCs have the advantages of high energy efficiency and low emissions and hold the potential to be the power of the future especially for small power generation systems (1-10 kW). Another unique advantage of SOFCs is the potential to directly utilize hydrocarbon fuels such as natural gas through internal reforming. However, all hydrocarbon fuels contain some sulfur compounds, which transform to hydrogen sulfide (H2S) in the reforming process and dramatically degrade the performance of the existing SOFCs. In this study, the interactions between sulfur contaminant (in the form of H2S) and the anodes for SOFCs were systematically investigated in order to gain a fundamental understanding of the mechanism of sulfur poisoning and ultimately to achieve rational design of sulfur-tolerant anodes. The sulfur poisoning behavior of the state-of-the-art Ni-YSZ cermet anodes was characterized using electrochemical measurements performed on button cells (of different structures) under various operating conditions, including H2S concentration, temperature, cell current density/terminal voltage, and cell structure. Also, the mechanisms of interactions between sulfur and the Ni-YSZ cermet anode were investigated using both ex situ and in situ characterization techniques such as Raman spectroscopy. Results suggest that the sulfur poisoning of Ni-YSZ cermet anodes at high temperatures in fuels with ppm-level H2S is due not to the formation of multi-layer conventional nickel sulfides but to the adsorption of sulfur on the nickel surface. In addition, new sulfur-tolerant anode materials were explored in this study. Thermodynamic principles were applied to predict the stability of candidate sulfur-tolerant anode materials and explain complex phenomena concerning the reactivity of candidate materials with

  9. Investigation of Bose-Einstein correlations in 3 jet events with the DELPHI detector

    CERN Document Server

    Van Remortel, N; Mandl, F

    2002-01-01

    A preliminary investigation of Bose-Einstein correlations in 3 jet events has been made by analysing the collected data at the Z/sup 0/ peak from '94 and '95 and the calibration runs during the LEP2 period from '97 to 2000. Three methods were used to extract two-particle correlation functions. No significant difference was found between quark and gluon jets for all three methods. (11 refs).

  10. Investigation of Bose-Einstein Correlations in 3 jet events with the DELPHI detector

    CERN Document Server

    van Remortel, N.; Mandl, F.

    2001-01-01

    A preliminary investigation of Bose-Einstein correlations in 3 jet events has been made by analysing the collected data at the $Z^0$ peak from '94 and '95 and the calibration runs during the LEP2 period from '97 to 2000. Three methods were used to extract two-particle correlation functions. No significant difference was found between quark and gluon jets for all three methods.

  11. Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Whitty

    2007-06-30

    University of Utah's project entitled 'Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer' (DOE Cooperative Agreement DE-FC26-02NT41490) was developed in response to a solicitation released by the U.S. Department of Energy in December 2001, requesting proposals for projects targeted towards black liquor/biomass gasification technology support research and development. Specifically, the solicitation was seeking projects that would provide technical support for Department of Energy supported black liquor and biomass gasification demonstration projects under development at the time.

  12. Experimental and Numerical Investigation of Humidity Effect on Performance of PEM Fuel Cells

    DEFF Research Database (Denmark)

    Liso, Vincenzo; Al Shakhshir, Saher; Nielsen, Mads Pagh

    2017-01-01

    In this study, a single proton exchange membrane fuel cell electrical performance is tested and modelled. The aim is to investigate the effect of reactants and membrane humidity on cell electrical performance. We discuss cell performance in terms of various variables affecting water transport...... in the membrane, such as electro-osmotic drag, water diffusion and ionic conductivity. The experimental results show that membrane hydration mainly affects ohmic losses and especially when humidity at cathode side is reduced. The developed model can estimate the contribution of different overpotentials...

  13. Water transport in gas diffusion media for PEM fuel cells. Experimental and numerical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Joerg

    2010-08-20

    The water flux in partially saturated hydrophobic carbon fibre paper for polymer electrolyte membrane fuel cell applications is investigated and compared with the frequently used constitutive two-phase flow model based on Darcy's law. Further, the first steps towards a math-based material design for gas diffusion media are explored in this thesis. Two self-developed ex-situ experiments to investigate the liquid water transport are introduced. The first is a newly developed buoyancy-based measurement of the pressuresaturation relationship on thin porous material with an accuracy of 0.5 kPa for the pressure and {+-} 5% for the saturation. The second experiment measures the pressure drop in dependence of flow rates down to magnitudes of {mu}L/s across the partially saturated thin porous material. This flow rate is relevant for the fuel cell application. The liquid water transport through Toray 060 carbon fibre paper, impregnated with 7% and 10% PTFE is investigated at wet and dry boundary conditions. The experiments are also accompanied by analytical and numerical free surface modelling with the consideration of the material morphology and liquid-solid interaction. The imbibing and draining cases of an arrangement of six fibres at varying solid-liquid interaction and boundary conditions are studied with 'Surface Evolver'. In order to evaluate the findings of ex-situ and modelling work for applicability to water transport in fuel cell operation, the technique of nuclear magnetic resonance (NMR) imaging is assessed. The focus is on the visualisation of 2D and 3D water distribution in the operating fuel cell. The compatibility of the NMR experiment with fuel cell operation in relation to material selection, operating temperature, and current density is addressed. NMR imaging is employed for different current densities, stoichiometries, and fuel cell arrangements. The fuel cell arrangements differ by the cathode diffusion medium. Plain, hydrophobic, and

  14. Creatine kinase-mediated ATP supply fuels actin-based events in phagocytosis.

    Directory of Open Access Journals (Sweden)

    Jan W P Kuiper

    2008-03-01

    Full Text Available Phagocytosis requires locally coordinated cytoskeletal rearrangements driven by actin polymerization and myosin motor activity. How this actomyosin dynamics is dependent upon systems that provide access to ATP at phagosome microdomains has not been determined. We analyzed the role of brain-type creatine kinase (CK-B, an enzyme involved in high-energy phosphoryl transfer. We demonstrate that endogenous CK-B in macrophages is mobilized from the cytosolic pool and coaccumulates with F-actin at nascent phagosomes. Live cell imaging with XFP-tagged CK-B and beta-actin revealed the transient and specific nature of this partitioning process. Overexpression of a catalytic dead CK-B or CK-specific cyclocreatine inhibition caused a significant reduction of actin accumulation in the phagocytic cup area, and reduced complement receptor-mediated, but not Fc-gammaR-mediated, ingestion capacity of macrophages. Finally, we found that inhibition of CK-B affected phagocytosis already at the stage of particle adhesion, most likely via effects on actin polymerization behavior. We propose that CK-B activity in macrophages contributes to complement-induced F-actin assembly events in early phagocytosis by providing local ATP supply.

  15. Investigation of convective transport in the gas diffusion layer used in polymer electrolyte fuel cells

    Science.gov (United States)

    Beruski, Otávio; Lopes, Thiago; Kucernak, Anthony R. J.; Perez, Joelma

    2017-10-01

    Recent experimental data on a fuel-cell-like system revealed insights into the fluid flow in both free and porous media. A computational model is used to investigate the momentum and species transport in such a system, solved using the finite element method. The model consists of a stationary, isothermal, diluted species transport in free and porous media flow. The momentum transport is treated using different formulations, namely, Stokes-Darcy, Darcy-Brinkman, and hybrid Stokes-Brinkman formulations. The species transport is given by the advection equation for a reactant diluted in air. The formulations are compared to each other and to the available experimental data, where it is concluded that the Darcy-Brinkman formulation reproduces the data appropriately. The validated model is used to investigate the contribution of convection in reactant transport in porous media of fuel cells. Convective transport provides a major contribution to reactant distribution in the so-called diffusion media. For a serpentine channel and flow with Re =260 -590 , convection accounts for 29-58% of total reactant transport to the catalyst layer.

  16. Crossing borders between social and physical sciences in post-event investigations

    Science.gov (United States)

    Ruin, I.; Gruntfest, E.; Lutoff, C.; Anquetin, S.; Scolobig, A.; Creutin, J.-D.; Borga, M.

    2009-04-01

    In natural hazard research social and physical scientists tend to approach post-event investigations within their narrow disciplinary lenses. Efforts that are called trans-disciplinary often add social science but do not integrate it effectively. For example, an economist might be brought in to address a question of "value" without any understanding or interest in the context in which the value will be applied (e.g., Merrell et al. 2002, Simmons and Sutter 2005). At the same time, social scientists would benefit from some knowledge of geology, meteorology, hydrology, forecasting operations, and hazard detection systems in order, for instance, to understand the nature and types of uncertainty in the physical systems. Proactive partnership between social and physical scientists in post-event investigations needs a background knowledge and a preparation about several issues from both sides. Moreover neither physical nor social scientists necessarily understand and appreciate the contributions that they can reciprocally bring to their works. Post-event collaborations between social and physical science are rare. The few examples of multi-disciplinary work, when examined closely, are not integrated collaborative projects but patchwork quilts of a variety of specialists taking separate aspects of an issue. There are examples where social scientists and engineers are engaged in one project, but the efforts tend to include social scientists as an "add on" to an existing physical science investigation. In this way, true integration of information, data and knowledge from different fields is lacking and the result is that neither the physical nor the social science perspectives gain a comprehensive picture of the issue under scrutiny. Looking at the flash flood problem, the atmospheric and hydrological generating mechanisms of the phenomenon are poorly understood, leading to highly uncertain forecasts of and warnings for these events. On the other hand warning and crisis

  17. Landslide Event on 24 June in Sichuan Province, China: Preliminary Investigation and Analysis

    Directory of Open Access Journals (Sweden)

    Wanlin Meng

    2018-01-01

    Full Text Available This paper reports on a massive landslide event, in which 8 million cubic meters of earth and rocks slid down from the top of a mountain in the village of Xinmo, located in the county of Maoxian, in the province of Sichuan, China, on 24 June 2017. This landslide resulted in 10 fatalities and 73 people were reported as missing. This paper details the preliminary investigation, the joint-force rescue activity, and the analysis of the nearby topography, rainfall, and seismic fracture zone. The combined effects of large amounts of rainwater, steep topography, deep-seated sliding interface, and significant altitude difference between the highest point of the mountain and the Xinmo villagers’ houses are considered as the main influencing factor that triggered this landslide event. To develop geological disaster-prone areas in the future, four main recommendations to reduce casualties and environmental impacts are provided in this paper.

  18. Investigation of Micro- and Macro-Scale Transport Processes for Improved Fuel Cell Performance

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Wenbin [General Motors LLC, Pontiac, MI (United States)

    2014-08-29

    This report documents the work performed by General Motors (GM) under the Cooperative agreement No. DE-EE0000470, “Investigation of Micro- and Macro-Scale Transport Processes for Improved Fuel Cell Performance,” in collaboration with the Penn State University (PSU), University of Tennessee Knoxville (UTK), Rochester Institute of Technology (RIT), and University of Rochester (UR) via subcontracts. The overall objectives of the project are to investigate and synthesize fundamental understanding of transport phenomena at both the macro- and micro-scales for the development of a down-the-channel model that accounts for all transport domains in a broad operating space. GM as a prime contractor focused on cell level experiments and modeling, and the Universities as subcontractors worked toward fundamental understanding of each component and associated interface.

  19. Investigation of Acute Pulmonary Deficits Associated with Biomass Fuel Cookstove Emissions in Rural Bangladesh

    Directory of Open Access Journals (Sweden)

    Danielle N. Medgyesi

    2017-06-01

    Full Text Available The use of solid biomass fuels in cookstoves has been associated with chronic health impacts that disproportionately affect women worldwide. Solid fuel stoves that use wood, plant matter, and cow dung are commonly used for household cooking in rural Bangladesh. This study investigates the immediate effects of acute elevated cookstove emission exposures on pulmonary function. Pulmonary function was measured with spirometry before and during cooking to assess changes in respiratory function during exposure to cookstove emissions for 15 females ages 18–65. Cookstove emissions were characterized using continuous measurements of particulate matter (PM2.5—aerodynamic diameter <2.5 μm concentrations at a 1 s time resolution for each household. Several case studies were observed where women ≥40 years who had been cooking for ≥25 years suffered from severe pulmonary impairment. Forced expiratory volume in one second over forced vital capacity (FEV1/FVC was found to moderately decline (p = 0.06 during cooking versus non-cooking in the study cohort. The study found a significant (α < 0.05 negative association between 3- and 10-min maximum PM2.5 emissions during cooking and lung function measurements of forced vital capacity (FVC, forced expiratory volume in one second (FEV1, and FEV1/FVC obtained during cooking intervals. This study found that exposure to biomass burning emissions from solid fuel stoves- associated with acute elevated PM2.5 concentrations- leads to a decrease in pulmonary function, although further research is needed to ascertain the prolonged (e.g., daily, for multiple years impacts of acute PM2.5 exposure on immediate and sustained respiratory impairment.

  20. Heavy fuel oil pyrolysis and combustion: kinetics and evolved gases investigated by TGA-FTIR

    KAUST Repository

    Abdul Jameel, Abdul Gani

    2017-08-24

    Heavy fuel oil (HFO) obtained from crude oil distillation is a widely used fuel in marine engines and power generation technologies. In the present study, the pyrolysis and combustion of a Saudi Arabian HFO in nitrogen and in air, respectively, were investigated using non-isothermal thermo-gravimetric analysis (TGA) coupled with a Fourier-transform infrared (FTIR) spectrometer. TG and DTG (differential thermo-gravimetry) were used for the kinetic analysis and to study the mass loss characteristics due to the thermal degradation of HFO at temperatures up to 1000°C and at various heating rates of 5, 10 and 20°C/min, in air and N2 atmospheres. FTIR analysis was then performed to study the composition of the evolved gases. The TG/DTG curves during HFO combustion show the presence of three distinct stages: the low temperature oxidation (LTO); fuel decomposition (FD); and high temperature oxidation (HTO) stages. The TG/DTG curves obtained during HFO pyrolysis show the presence of two devolatilization stages similar to that seen in the LTO stage of HFO combustion. Apart from this, the TG/DTG curves obtained during HFO combustion and pyrolysis differ significantly. Kinetic analysis was also performed using the distributed activation energy model, and the kinetic parameter (E) was determined for the different stages of HFO combustion and pyrolysis processes, yielding a good agreement with the measured TG profiles. FTIR analysis showed the signal of CO2 as approximately 50 times more compared to the other pollutant gases under combustion conditions. Under pyrolytic conditions, the signal intensity of alkane functional groups was the highest followed by alkenes. The TGA-FTIR results provide new insights into the overall HFO combustion processes, which can be used to improve combustor designs and control emissions.

  1. Investigation and basic evaluation for ultra-high burnup fuel cladding material

    Energy Technology Data Exchange (ETDEWEB)

    Ioka, Ikuo; Nagase, Fumihisa; Futakawa, Masatoshi; Kiuchi, Kiyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Suga, Masataka [Kokan Keisoku Co., Kawasaki, Kanagawa (Japan)

    2001-03-01

    In ultra-high burnup of the power reactor, it is an essential problem to develop the cladding with excellent durability. First, development history and approach of the safety assessment of Zircaloy for the high burnup fuel were summarized in the report. Second, the basic evaluation and investigation were carried out on the material with high practicability in order to select the candidate materials for the ultra-high burnup fuel. In addition, the basic research on modification technology of the cladding surface was carried out from the viewpoint of the addition of safety margin as a cladding. From the development history of the zirconium alloy including the Zircaloy, it is hard to estimate the results of in-pile test from those of the conventional corrosion test (out-pile test). Therefore, the development of the new testing technology that can simulate the actual environment and the elucidation of the corrosion-controlling factor of the cladding are desired. In cases of RIA (Reactivity Initiated Accident) and LOCA (Loss of Coolant Accident), it seems that the loss of ductility in zirconium alloys under heavy irradiation and boiling of high temperature water restricts the extension of fuel burnup. From preliminary evaluation on the high corrosion-resistance materials (austenitic stainless steel, iron or nickel base superalloys, titanium alloy, niobium alloy, vanadium alloy and ferritic stainless steel), stabilized austenitic stainless steels with a capability of future improvement and high-purity niobium alloys with a expectation of the good corrosion resistance were selected as candidate materials of ultra-high burnup cladding. (author)

  2. Investigation of High Pressure, Multi-Hole Diesel Fuel Injection Using High Speed Imaging

    Science.gov (United States)

    Morris, Steven; Eagle, Ethan; Wooldridge, Margaret

    2012-10-01

    Research to experimentally capture and understand transient fuel spray behavior of modern fuel injection systems remains underdeveloped. To this end, a high-pressure diesel common-rail fuel injector was instrumented in a spherical, constant volume combustion chamber to image the early time history of injection of diesel fuel. The research-geometry fuel injector has four holes aligned on a radial plane of the nozzle with hole sizes of 90, 110, 130 and 150 μm in diameter. Fuel was injected into a non-reacting environment with ambient densities of 17.4, 24.0, and 31.8 kg/m3 at fuel rail pressures of 1000, 1500, and 2000 bar. High speed images of fuel injection were taken using backlighting at 100,000 frames per second (100 kfps) and an image processing algorithm. The experimental results are compared with a one-dimensional fuel-spray model that was historically developed and applied to fuel sprays from single-hole fuel injectors. Fuel spray penetration distance was evaluated as a function of time for the different injector hole diameters, fuel injection pressures and ambient densities. The results show the differences in model predictions and experimental data at early times in the spray development.

  3. LC-MS-Based Metabolomic Investigation of Chemopreventive Phytochemical-Elicited Metabolic Events.

    Science.gov (United States)

    Wang, Lei; Yao, Dan; Chen, Chi

    2016-01-01

    Phytochemicals are under intensive investigation for their potential use as chemopreventive agents in blocking or suppressing carcinogenesis. Metabolic interactions between phytochemical and biological system play an important role in determining the efficacy and toxicity of chemopreventive phytochemicals. However, complexities of phytochemical biotransformation and intermediary metabolism pose challenges for studying phytochemical-elicited metabolic events. Metabolomics has become a highly effective technical platform to detect subtle changes in a complex metabolic system. Here, using green tea polyphenols as an example, we describe a workflow of LC-MS-based metabolomics study, covering the procedures and techniques in sample collection, preparation, LC-MS analysis, data analysis, and interpretation.

  4. 26 CFR 48.4081-3 - Taxable fuel; taxable events other than removal at the terminal rack.

    Science.gov (United States)

    2010-04-01

    ... taxable fuel. For this purpose, the alcohol in gasohol is treated as previously taxed taxable fuel. (2....4081-1, by mixing 1,000 gallons of a liquid that has not been taxed under section 4081 with 4,000 gallons of diesel fuel that has been taxed under section 4081. The mixing occurs outside of the bulk...

  5. Experimental investigation of the ignition and flammability limits of various hydrocarbon fuels in a two-dimensional solid-fuel ramjet. Master's thesis

    Energy Technology Data Exchange (ETDEWEB)

    Wooldridge, R.C.

    1987-06-01

    An experimental investigation was conducted to study the effects of inlet step height on ignition and flammability limits and recirculation-zone and boundary-layer combustion phenomena of various hydrocarbon fuels. A windowed two-dimensional solid-fuel ramjet (SFRJ) was utilized. Hydrocarbon fuels were burned under conditions similar to the actual flight were studied using a variable geometry inlet, an automatic data acquisition system, and high speed motion pictures of the interior of the combustion chamber at the recirculation zone and the boundary layer development region. Data was obtained at a mass flux of 0.2 1bm/in2-sec at a nominal air inlet temperature of 1000 R with pressures ranging from 100 to 150 psia.

  6. Numerical Investigation of Injection Timing Influence on Fuel Slip and Influence of Compression Ratio on Knock Occurrence in Conventional Dual Fuel Engine

    Directory of Open Access Journals (Sweden)

    Mario Sremec

    2017-12-01

    Full Text Available Compressed natural gas can be used in diesel engine with great benefits, but because of its low reactivity it is usually used in a so called dual fuel combustion process. Optimal parameters for dual fuel engines are not yet investigated thoroughly which is the motivation for this work. In this work, a numerical study performed in a cycle simulation tool (AVL Boost v2013 on the influence of different injection timings on fuel slip into exhaust and influence of compression ratio on knock phenomena in port injected dual fuel engine was conducted. The introduction of natural gas into the intake port of a diesel engine usually results in some fuel slipping into the exhaust port due to valve overlap. By analysing the simulation results, the injection strategy that significantly decreases the natural gas slip is defined. The knock occurrence study showed that the highest allowed compression ratio that will result in knock free operation of the presented engine is 18 for ambient intake condition, while for charged intake conditions the compression ratio should be lowered to 16.

  7. Investigation into the Implications of Fuel Cell Shipboard Integration into the T-AGOS 19 Class

    Science.gov (United States)

    2012-02-01

    with each defined by its fundamental electrolyte: i. Alkali Fuel Cells (AFC) ii. Polymer Exchange Membrane ( PEM ) iii. Phosphoric Acid Fuel Cells ...of the PEM family (High Temperature – HTPEM and Direct Methanol Fuel Cells – DMFC) were assessed against a range of basic ship requirements...of Stationary PEM Fuel Cell Systems”, DOE hydrogen program 2010 annual report. [11] US Energy Information Administration, “EIA - Weekly Retail

  8. Thermal Hydraulic Computational Fluid Dynamics Simulations and Experimental Investigation of Deformed Fuel Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Mays, Brian [AREVA Federal Services, Lynchburg, VA (United States); Jackson, R. Brian [TerraPower, Bellevue, WA (United States)

    2017-03-08

    The project, Toward a Longer Life Core: Thermal Hydraulic CFD Simulations and Experimental Investigation of Deformed Fuel Assemblies, DOE Project code DE-NE0008321, was a verification and validation project for flow and heat transfer through wire wrapped simulated liquid metal fuel assemblies that included both experiments and computational fluid dynamics simulations of those experiments. This project was a two year collaboration between AREVA, TerraPower, Argonne National Laboratory and Texas A&M University. Experiments were performed by AREVA and Texas A&M University. Numerical simulations of these experiments were performed by TerraPower and Argonne National Lab. Project management was performed by AREVA Federal Services. The first of a kind project resulted in the production of both local point temperature measurements and local flow mixing experiment data paired with numerical simulation benchmarking of the experiments. The project experiments included the largest wire-wrapped pin assembly Mass Index of Refraction (MIR) experiment in the world, the first known wire-wrapped assembly experiment with deformed duct geometries and the largest numerical simulations ever produced for wire-wrapped bundles.

  9. Calibration method for carbon dioxide sensors to investigate direct methanol fuel cell efficiency

    Science.gov (United States)

    Stähler, M.; Burdzik, A.

    2014-09-01

    Methanol crossover is a process in direct methanol fuel cells which causes significant reduction of cell efficiency. Methanol permeates through the membrane electrode assembly and reacts at the cathode with oxygen to form carbon dioxide. This process is undesirable because it does not generate electric energy, but rather only increases heat production. Different procedures have been used for the investigation of this crossover. One method uses the detection of carbon dioxide in the exhaust gas of the cathode by means of a carbon dioxide sensor. This technique is inexpensive and enables real-time measurements but its disadvantage is the low accuracy. This paper demonstrates a simple method to generate gas mixtures for the calibration of the sensor in order to increase the accuracy. The advantages of this technique consist in the fact that only the existing devices of a direct methanol fuel cell test rig are needed and that the operator can adjust the carbon dioxide concentration for the calibration process. This is important for dealing with nonlinearities of the sensor. A detailed error analysis accompanies the experiments. At the end it is shown that the accuracy of the determined Faraday efficiency can be improved by using the presented calibration technique.

  10. Design of an 80 kWe PEM fuel cell system: Scale up effect investigation

    Energy Technology Data Exchange (ETDEWEB)

    Bonnet, C.; Carre, P. [Laboratoire des Sciences du Genie Chimique, Nancy-University-CNRS, 1 rue Grandville, BP20451, 54001 Nancy (France); Didierjean, S.; Colinart, T. [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee, Nancy-University-CNRS, 2 avenue de la Foret de Haye, 54504 Vandoeuvre les Nancy (France); Guillet, N. [CEA-Grenoble LITEN/DTH/LCPEM, 17, rue des martyrs, 38054 Grenoble Cedex 9 (France); Besse, S. [Helion, Domaine du Petit Arbois, Batiment Jules Verne, BP71, 13545 Aix en Provence Cedex 4 (France)

    2008-08-01

    In the frame of SPACT-80 project to design and manufacture a robust and durable air/hydrogen 80 kWe PEM fuel cell for transportation application, experiments have been carried out on various electrode active surfaces since the full scale system could be damaged by some particular operating conditions. Thus, the main objective of this paper was to verify that a 25 cm{sup 2} single cell, a 5-cell pilot stack and a 90-cell stack exhibit the same behaviour and that they are representative of the full device's performance. After a brief description of the studied device the scaling up effect was checked. In non-optimal conditions, experiments were mainly conducted on single cell and pilot stack. In driving cycle and when studying various gas flows, they present similar evolution for the cell voltage as well as for the water management. The water transport coefficient and the diffusion resistance values determined by impedance spectroscopy highlight the presence of liquid water that could have an effect on the gas transport to the electrode. Investigation on the air humidification conditions shows that at lower relative humidity (RH), the two fuel cells have similar behaviour but above 60% RH different evolutions appear. Whatever the air humidification conditions, liquid water is present in both compartments. (author)

  11. Experimental investigations on mixing of two biodiesels blended with diesel as alternative fuel for diesel engines

    Directory of Open Access Journals (Sweden)

    K. Srithar

    2017-01-01

    Full Text Available The world faces the crises of energy demand, rising petroleum prices and depletion of fossil fuel resources. Biodiesel has obtained from vegetable oils that have been considered as a promising alternate fuel. The researches regarding blend of diesel and single biodiesel have been done already. Very few works have been done with the combination of two different biodiesel blends with diesel and left a lot of scope in this area. The present study brings out an experiment of two biodiesels from pongamia pinnata oil and mustard oil and they are blended with diesel at various mixing ratios. The effects of dual biodiesel works in engine and exhaust emissions were examined in a single cylinder, direct injection, air cooled and high speed diesel engine at various engine loads with constant engine speed of 3000 rpm. The influences of blends on CO, CO2, HC, NOx and smoke opacity were investigated by emission tests. The brake thermal efficiency of blend A was found higher than diesel. The emissions of smoke, hydro carbon and nitrogen oxides of dual biodiesel blends were higher than that of diesel. But the exhaust gas temperature for dual biodiesel blends was lower than diesel.

  12. Numerical investigation on the regression rate of hybrid rocket motor with star swirl fuel grain

    Science.gov (United States)

    Zhang, Shuai; Hu, Fan; Zhang, Weihua

    2016-10-01

    Although hybrid rocket motor is prospected to have distinct advantages over liquid and solid rocket motor, low regression rate and insufficient efficiency are two major disadvantages which have prevented it from being commercially viable. In recent years, complex fuel grain configurations are attractive in overcoming the disadvantages with the help of Rapid Prototyping technology. In this work, an attempt has been made to numerically investigate the flow field characteristics and local regression rate distribution inside the hybrid rocket motor with complex star swirl grain. A propellant combination with GOX and HTPB has been chosen. The numerical model is established based on the three dimensional Navier-Stokes equations with turbulence, combustion, and coupled gas/solid phase formulations. The calculated fuel regression rate is compared with the experimental data to validate the accuracy of numerical model. The results indicate that, comparing the star swirl grain with the tube grain under the conditions of the same port area and the same grain length, the burning surface area rises about 200%, the spatially averaged regression rate rises as high as about 60%, and the oxidizer can combust sufficiently due to the big vortex around the axis in the aft-mixing chamber. The combustion efficiency of star swirl grain is better and more stable than that of tube grain.

  13. Meteotsunamis in the Great Lakes and Investigation into the May 27, 2012 Event on Lake Erie

    Science.gov (United States)

    Anderson, E. J.; Bechle, A.; Wu, C. H.; Schwab, D. J.; Mann, G.

    2016-02-01

    Meteotsunami events have been documented in several countries around the world in the coastal ocean, semi-enclosed basins, and in the Great Lakes. In particular, investigations in the Great Lakes have raised the issue of dangers posed by enclosed basins due to the reflection and interaction of meteotsunami waves, in which the destructive waves can arrive several hours after the atmospheric disturbance has passed. This disassociation in time and space between the atmospheric disturbance and resultant meteotsunami wave can pose a significant threat to the public. In a recent event on May 27, 2012, atmospheric conditions gave rise to two convective systems that generated a series of waves in the meteotsunami band on Lake Erie. The resulting waves swept three swimmers a half-mile offshore, inundated a marina, and may have led to a capsized boat along the southern shoreline. Examination of the observed conditions shows that these events occurred at a time between the arrivals of these two storm systems when atmospheric conditions were relatively calm but water level displacements were at their greatest. In this work, we attempt to explain the processes that led to these conditions through a combination of atmospheric and hydrodynamic modeling and an analysis of the observed radial velocities associated with the meteotsunami-inducing front. Results from a high-resolution atmospheric model and hydrodynamic model reveal that the formation of these destructive waves resulted from a combination of wave reflection, focusing, and edge waves that impacted the southern shore of Lake Erie. This event illustrates the unique danger posed by temporal lags between the inducing atmospheric conditions and resulting dangerous nearshore wave conditions.

  14. Investigation of Performance Analysis and Emission Characteristics of Waste Plastic Fuel

    Science.gov (United States)

    Ruban, M.; Ramasubramanian, S.; Pugazhenthi, R.; Sivaganesan

    2017-03-01

    Today the world is confronted with the twin crisis of fossil fuel depletion and stringent emission norms, because of the environmental awareness. The disposal and degradation of waste plastic is a major issue and scarcities of fuel were major focus area of the researchers. In this virtue the waste plastic fuel extraction makes more attention to the researchers. In this research work focused to find the performance of the waste plastic fuel and compared to diesel. The waste plastic fuel extract from thermal cracking method this process the polymer chains were breakdown into useful lower molecular weight compounds and it becomes plastic pyrolysis it can be utilized as a fuel. The properties of the waste plastic fuel is obtained by various testing process and which is analyze and compare with the fossil fuel diesel. It is found that almost it has similar properties to the diesel and almost all properties of the pyrolysis is closer to that of diesel. The characteristics of the pyrolysis were tested in the engine test bed. The pyrolysis / waste plastic fuel can be directly used in diesel engines over the entire load spectrum smoothly without any major modification. The performance of the waste plastic fuel / pyrolysis is evidenced that it is one of the best alternative fuel as well as the waste plastic can be converted into a useful fuel

  15. Understanding Our Energy Footprint: Undergraduate Chemistry Laboratory Investigation of Environmental Impacts of Solid Fossil Fuel Wastes

    Science.gov (United States)

    Berger, Michael; Goldfarb, Jillian L.

    2017-01-01

    Engaging undergraduates in the environmental consequences of fossil fuel usage primes them to consider their own anthropogenic impact, and the benefits and trade-offs of converting to renewable fuel strategies. This laboratory activity explores the potential contaminants (both inorganic and organic) present in the raw fuel and solid waste…

  16. Program of scientific investigations and development of solid-oxide fuel cells (SOFC) in VIITF proposals on scientific and technical collaboration and SOFC commercialization

    Energy Technology Data Exchange (ETDEWEB)

    Kleschev, Yu.N.; Chulharev, V.F.

    1996-04-01

    Investigations being performed at VNIITF covers the whole cycle of solid oxide fuel cell manufacturing. This report describes the main directions of investigations in materials, technologies, and commercialization.

  17. Design and Fluid Dynamic Investigations for a High Performance Light Water Reactor Fuel Assembly

    Science.gov (United States)

    Hofmeister, Jan; Laurin, Eckart; Class, Andreas G.

    2005-11-01

    Within the 5th Framework Program of the European Commission a nuclear light water reactor with supercritical steam conditions has been investigated called High Performance Light Water Reactor (HPLWR). This reactor concept is distinct from conventional light water reactor concepts by the fact, that supercritical water is used to achieve higher core outlet temperatures. The reactor operates with a high system pressure, high heat-up of the coolant within the core, and high outlet temperatures of the coolant resulting in a thermal efficiency of up to 44%. We present the design concept proposed by IKET, and a fluid dynamic problem in the foot piece of the fuel assembly, where unacceptable temperature variations must be omitted.

  18. Experimental Investigation of a Direct Methanol Fuel Cell with Hilbert Fractal Current Collectors

    Directory of Open Access Journals (Sweden)

    Jing-Yi Chang

    2014-01-01

    Full Text Available The Hilbert curve is a continuous type of fractal space-filling curve. This fractal curve visits every point in a square grid with a size of 2×2, 4×4, or any other power of two. This paper presents Hilbert fractal curve application to direct methanol fuel cell (DMFC current collectors. The current collectors are carved following first, second, and third order Hilbert fractal curves. These curves give the current collectors different free open ratios and opening perimeters. We conducted an experimental investigation into DMFC performance as a function of the free open ratio and opening perimeter on the bipolar plates. Nyquist plots of the bipolar plates are made and compared using electrochemical impedance spectroscopy (EIS experiments to understand the phenomena in depth. The results obtained in this paper could be a good reference for future current collector design.

  19. Investigation of altenative carbon materials for fuel-cell catalyst support

    DEFF Research Database (Denmark)

    Larsen, Mikkel Juul

    In order to ensure high utilization of the catalyst material in a polymer electrolyte membrane fuel cell (PEMFC) it is usually fixed in the form of nanoparticles on a supporting material. The catalyst is platinum or a platinum alloy, and the commonly used support is carbon black (CB). Although...... structured carbon forms such as graphitized CBs, carbon nanotubes (CNTs), and carbon nanofibres (CNFs). This thesis concerns the investigation of an array of different materials which may prospec-tively replace the conventional materials used in the catalyst. The study comprised 13 carbon samples which...... nanotubes (GMWCNTs), and graphitized carbon nanofibre (CNF), while the Pt/C samples were platinized samples of some of the CNTs and CNFs (Pt/FWCNT, Pt/GMWCNT, and Pt/CNF, respectively) as well as two commercial Pt/CB reference catalysts. Comparative analyses have been performed in order to be able to assess...

  20. Investigation of gas generation in regenerative fuel cells by low-energy X-rays

    Science.gov (United States)

    Selamet, Omer Faruk; Deevanhxay, Phengxay; Tsushima, Shohji; Hirai, Shuichiro

    2015-11-01

    Gas generation and discharge behaviors in an operating regenerative fuel cell (RFC) are investigated using low-energy X-ray radiography. In situ visualization at high spatial and temporal resolution reveal dynamic and inhomogeneous behaviors of the gas generation in the membrane electrode assembly (MEA) in the RFC. Temporal and spatial variation of the gas thickness in the MEA is quantitatively discussed and shows an intermittent and periodic discharge processes of the gas generated by electrolysis, suggesting that the reaction sites in the catalyst layer and the discharging path of gas bubbles are well established in the MEA for the electrolysis. Larger gas accumulation and discharge in the gas diffusion layer (GDL) under the ribs are identified in comparison with those under the channels, which is attributed to the relatively longer path for accumulated gas under the ribs to be discharged into the flow channels.

  1. Investigation on the gaseous and particulate emissions of a compression ignition engine fueled with diesel-dimethyl carbonate blends.

    Science.gov (United States)

    Cheung, C S; Zhu, Ruijun; Huang, Zuohua

    2011-01-01

    The effect of dimethyl carbonate (DMC) on the gaseous and particulate emissions of a diesel engine was investigated using Euro V diesel fuel blended with different proportions of DMC. Combustion analysis shows that, with the blended fuel, the ignition delay and the heat release rate in the premixed combustion phase increase, while the total combustion duration and the fuel consumed in the diffusion combustion phase decrease. Compared with diesel fuel, with an increase of DMC in the blended fuel, the brake thermal efficiency is slightly improved but the brake specific fuel consumption increases. On the emission side, CO increases significantly at low engine load but decreases at high engine load while HC decreases slightly. NO(x) reduces slightly but the reduction is not statistically significant, while NO(2) increases slightly. Particulate mass and number concentrations decrease upon using the blended fuel while the geometric mean diameter of the particles shifts towards smaller size. Overall speaking, diesel-DMC blends lead to significant improvement in particulate emissions while the impact on CO, HC and NO(x) emissions is small. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. Investigation of the climatic and environmental context of Hendra virus spillover events 1994-2010.

    Science.gov (United States)

    McFarlane, Rosemary; Becker, Niels; Field, Hume

    2011-01-01

    Hendra virus is a recently emerged bat-borne zoonotic agent with high lethality in horses and humans in Australia. This is a rare disease and the determinants of bat to horse transmission, including the factors that bring these hosts together at critical times, are poorly understood. In this cross-disciplinary study climatic and vegetation primary productivity variables are compared for the dispersed and heterogenic 1994-2010 outbreak sites. The significant occurrence of spillover events within the dry season (p =  0.013, 95% CI (0.57-0.98)) suggests seasonal forcing of transmission across species, or seasonal forcing of virus excretion by the reservoir host. We explore the evidence for both. Preliminary investigations of the spatial determinants of Hendra disease locations are also presented. We find that postal areas in the Australian state of Queensland in which pteropid fruit bat (flying fox) roosts occur are approximately forty times more likely (OR = 40.5, (95% CI (5.16, 317.52)) to be the location of Hendra spillover events. This appears to be independent of density of horses at these locations. We consider issues of scale of host resource use, land use change and limitations of existing data that challenge analysis and limit further conclusive outcomes. This investigation of a broad range of potential climatic and environmental influences provides a good base for future investigations. Further understanding of cross-species Hendra virus transmission requires better understanding of flying fox resource use in the urban-rural landscape.

  3. Investigation of the climatic and environmental context of Hendra virus spillover events 1994-2010.

    Directory of Open Access Journals (Sweden)

    Rosemary McFarlane

    Full Text Available Hendra virus is a recently emerged bat-borne zoonotic agent with high lethality in horses and humans in Australia. This is a rare disease and the determinants of bat to horse transmission, including the factors that bring these hosts together at critical times, are poorly understood. In this cross-disciplinary study climatic and vegetation primary productivity variables are compared for the dispersed and heterogenic 1994-2010 outbreak sites. The significant occurrence of spillover events within the dry season (p =  0.013, 95% CI (0.57-0.98 suggests seasonal forcing of transmission across species, or seasonal forcing of virus excretion by the reservoir host. We explore the evidence for both. Preliminary investigations of the spatial determinants of Hendra disease locations are also presented. We find that postal areas in the Australian state of Queensland in which pteropid fruit bat (flying fox roosts occur are approximately forty times more likely (OR = 40.5, (95% CI (5.16, 317.52 to be the location of Hendra spillover events. This appears to be independent of density of horses at these locations. We consider issues of scale of host resource use, land use change and limitations of existing data that challenge analysis and limit further conclusive outcomes. This investigation of a broad range of potential climatic and environmental influences provides a good base for future investigations. Further understanding of cross-species Hendra virus transmission requires better understanding of flying fox resource use in the urban-rural landscape.

  4. Investigation of nucleation events vertical extent: a long term study at two different altitude sites

    Directory of Open Access Journals (Sweden)

    J. Boulon

    2011-06-01

    statistical analysis of the occurrence of nucleation over the whole lower troposphere. This work highlights the fact that nucleation can occur over a large vertical extent, at least the whole low tropospheric column, and also the fact that it occurs twice as frequently as actually detected in the planetary boundary layer. The role of sulfuric acid and ions in the nucleation process was investigated at the altitude station and no correlation was found between nucleation events and the estimated sulfuric acid concentrations. However, the contribution of ion-induced nucleation was found to be relatively high (12.49 ± 2.03 % of the total nucleation rate.

  5. Experimental Investigation Of Biogas-Biodiesel Dual Fuel Combustion In A Diesel Engine

    Directory of Open Access Journals (Sweden)

    Ramesha D. K.

    2015-06-01

    Full Text Available This study is an attempt at achieving diesel fuel equivalent performance from diesel engines with maximum substitution of diesel with renewable fuels. In this context the study has been designed to analyze the influence of B20 algae biodiesel as a pilot fuel in a biodiesel biogas dual fuel engine, and results are compared to those of biodiesel and diesel operation at identical engine settings. Experiments were performed at various loads from 0 to 100 % of maximum load at a constant speed of 1500 rpm. In general, B20 algae biodiesel is compatible with diesel in terms of performance and combustion characteristics. Dual fuel mode operation displays lower thermal efficiency and higher fuel consumption than for other fuel modes of the test run across the range of engine loads. Dual fuel mode displayed lower emissions of NOx and Smoke opacity while HC and CO concentrations were considerably higher as compared to other fuels. In dual fuel mode peak pressure and heat release rate were slightly higher compared to diesel and biodiesel mode of operation for all engine loads.

  6. In-Core Fuel Managements for PWRs: Investigation on solution for optimal utilization of PWR fuel through the use of fuel assemblies with differently enriched {sup 235}U fuel pins

    Energy Technology Data Exchange (ETDEWEB)

    Caprioli, Sara

    2004-04-01

    A possibility for more efficient use of the nuclear fuel in a pressurized water reactor is investigated. The alternative proposed here consists of the implementation of PWR fuel assemblies with differently enriched {sup 235}U fuel pins. This possibility is examined in comparison with the standard assembly design. The comparison is performed both in terms of single assembly performance and in the terms of nuclear reactor core performance and fuel utility. For the evaluation of the actual performance of the new assembly types, 5 operated fuel core sequences of R3 (Ringhals' third unit), for the period 1999 - 2004 (cycles 17 - 21) were examined. For every cycle, the standard fresh fuel assemblies have been identified and taken as reference cases for the study of the new type of assemblies with differently enriched uranium rods. In every cycle, assemblies with and without burnable absorber are freshly loaded into the core. The axial enrichment distribution is kept uniform, allowing for a radial (planar) enrichment level distribution only. At an assembly level, it has been observed that the implementation of the alternative enrichment configuration can lead to lower and flatter internal peaking factor distribution with respect to the uniformly enriched reference assemblies. This can be achieved by limiting the enrichment levels distribution to a rather narrow range. The highest enrichment level chosen has the greatest impact on the power distribution of the assemblies. As it increases, the enrichment level drives the internal peaking factor to greater values than in the reference assemblies. Generally, the highest enrichment level that would allow an improvement in the power performance of the assembly lies between 3.95 w/o and 4.17 w/o. The highest possible enrichment level depends on the average enrichment of the overall assembly, which is kept constant to the average enrichment of the reference assemblies. The improvements that can be obtained at this level are

  7. Investigations of a Combustor Using a 9-Point Swirl-Venturi Fuel Injector: Recent Experimental Results

    Science.gov (United States)

    Hicks, Yolanda R.; Heath, Christopher M.; Anderson, Robert C.; Tacina, Kathleen M.

    2012-01-01

    This paper explores recent results obtained during testing in an optically-accessible, JP8-fueled, flame tube combustor using baseline Lean Direct Injection (LDI) research hardware. The baseline LDI geometry has nine fuel/air mixers arranged in a 3 x 3 array. Results from this nine-element array include images of fuel and OH speciation via Planar Laser-Induced Fluorescence (PLIF), which describe fuel spray pattern and reaction zones. Preliminary combustion temperatures derived from Stokes/Anti-Stokes Spontaneous Raman Spectroscopy are also presented. Other results using chemiluminescence from major combustion radicals such as CH* and C2* serve to identify the primary reaction zone, while OH PLIF shows the extent of reaction further downstream. Air and fuel velocities and fuel drop size results are also reported.

  8. Investigation of IrO2/Pt Electrocatalysts in Unitized Regenerative Fuel Cells

    Directory of Open Access Journals (Sweden)

    V. Baglio

    2011-01-01

    Full Text Available IrO2/Pt catalysts (at different concentrations were synthesized by incipient wetness technique and characterized by XRD, XRF, and SEM. Water electrolysis/fuel cell performances were evaluated in a 5 cm2 single cell under Unitized Regenerative Fuel Cell (URFC configuration. The IrO2/Pt composition of 14/86 showed the highest performance for water electrolysis and the lowest one as fuel cell. It is derived that for fuel cell operation an excess of Pt favours the oxygen reduction process whereas IrO2 promotes oxygen evolution. From the present results, it appears that the diffusion characteristics and the reaction rate in fuel cell mode are significantly lower than in the electrolyser mode. This requires the enhancement of the gas diffusion properties of the electrodes and the catalytic properties for cathode operation in fuel cells.

  9. INVESTIGATION OF FOSSIL FUEL AND LIQUID BIOFUEL BLEND PROPERTIES USING ARTIFICIAL NEURAL NETWORK

    OpenAIRE

    Najafi, G.; B Ghobadian; P. Nematizade

    2012-01-01

    Gasoline fuel is the baseline fuel in this research, to which bioethanol, biodiesel and diesel are additives. The fuel blends were prepared based on different volumes and following which, ASTM (American Society for Testing and Materials) test methods analysed some of the important properties of the blends, such as: density, dynamic viscosity, kinematic viscosity and water and sediment. Experimental data were analysed by means of Matlab software. The results obtained from artificial neural net...

  10. Investigation of Redox Metal Oxides for Carbonaceous Fuel Conversion and CO2 Capture

    Science.gov (United States)

    Galinsky, Nathan Lee

    The chemical looping combustion (CLC) process uses metal oxides, also referred to as oxygen carriers, in a redox scheme for conversion of carbonaceous fuels into a concentrated stream of CO2 and steam while also producing heat and electricity. The unique redox scheme of CLC allows CO2 capture with minimal energy penalty. The CLC process performance greatly depends on the oxygen carrier that is chosen. To date, more than 1000 oxygen carriers have been developed for chemical-looping processes using metal oxides containing first-row transition metals. Oxygen carriers are typically mixed with an inert ceramic support to improve their overall mechanical stability and recyclability. This study focuses on design of (i) iron oxide oxygen carriers for conversion of gaseous carbonaceous fuels and (ii) development of perovskite CaMnO 3-d with improved stability and redox properties for conversion of solid fuels. Iron oxide is cheap and environmentally benign. However, it suffers from low activity with carbonaceous fuels due partially to the low ionic conductivity of iron oxides. In order to address the low activity of iron-oxide-based oxygen carriers, support addition has been shown to lower the energy barrier of oxygen anion transport within the oxygen carrier. This work adds a mixed-ionic-and-electronic-conductor (MIEC) support to iron oxide to help facilitate O2- transport inside the lattice of iron oxide. The MIEC-supported iron oxide is compared to commonly used supports including TiO2 and Al2O 3 and the pure ionic conductor support yttria-stabilized zirconia (YSZ) for conversion of different carbonaceous fuels and hydrogen. Results show that the MIEC-supported iron oxide exhibits up to 70 times higher activity than non-MIEC-supported iron oxides for methane conversion. The MIEC supported iron oxide also shows good recyclability with only minor agglomeration and carbon formation observed. The effect of support-iron oxide synergies is further investigated to understand

  11. Energy Optimization and Fuel Economy Investigation of a Series Hybrid Electric Vehicle Integrated with Diesel/RCCI Engines

    Directory of Open Access Journals (Sweden)

    Ali Solouk

    2016-12-01

    Full Text Available Among different types of low temperature combustion (LTC regimes, eactively controlled compression ignition (RCCI has received a lot of attention as a promising advanced combustion engine technology with high indicated thermal efficiency and low nitrogen oxides ( NO x and particulate matter (PM emissions. In this study, an RCCI engine for the purpose of fuel economy investigation is incorporated in series hybrid electric vehicle (SHEV architecture, which allows the engine to run completely in the narrow RCCI mode for common driving cycles. Three different types of energy management control (EMC strategies are designed and implemented to achieve the best fuel economy. The EMC strategies encompass rule-based control (RBC, offline, and online optimal controllers, including dynamic programing (DP and model predictive control (MPC, respectively. The simulation results show a 13.1% to 14.2% fuel economy saving by using an RCCI engine over a modern spark ignition (SI engine in SHEV for different driving cycles. This fuel economy saving is reduced to 3% in comparison with a modern compression ignition (CI engine, while NO x emissions are significantly lower. Simulation results show that the RCCI engine offers more fuel economy improvement in more aggressive driving cycles (e.g., US06, compared to less aggressive driving cycles (e.g., UDDS. In addition, the MPC results show that sub-optimal fuel economy is achieved by predicting the vehicle speed profile for a time horizon of 70 s.

  12. Analytical Investigation and Improvement of Performance of a Proton Exchange Membrane (Pem) Fuel Cell in Mobile Applications

    Science.gov (United States)

    Khazaee, I.

    2015-05-01

    In this study, the performance of a proton exchange membrane fuel cell in mobile applications is investigated analytically. At present the main use and advantages of fuel cells impact particularly strongly on mobile applications such as vehicles, mobile computers and mobile telephones. Some external parameters such as the cell temperature (Tcell ) , operating pressure of gases (P) and air stoichiometry (λair ) affect the performance and voltage losses in the PEM fuel cell. Because of the existence of many theoretical, empirical and semi-empirical models of the PEM fuel cell, it is necessary to compare the accuracy of these models. But theoretical models that are obtained from thermodynamic and electrochemical approach, are very exact but complex, so it would be easier to use the empirical and smi-empirical models in order to forecast the fuel cell system performance in many applications such as mobile applications. The main purpose of this study is to obtain the semi-empirical relation of a PEM fuel cell with the least voltage losses. Also, the results are compared with the existing experimental results in the literature and a good agreement is seen.

  13. Investigations into the low temperature behavior of jet fuels: Visualization, modeling, and viscosity studies

    Science.gov (United States)

    Atkins, Daniel L.

    Aircraft operation in arctic regions or at high altitudes exposes jet fuel to temperatures below freeze point temperature specifications. Fuel constituents may solidify and remain within tanks or block fuel system components. Military and scientific requirements have been met with costly, low freeze point specialty jet fuels. Commercial airline interest in polar routes and the use of high altitude unmanned aerial vehicles (UAVs) has spurred interest in the effects of low temperatures and low-temperature additives on jet fuel. The solidification of jet fuel due to freezing is not well understood and limited visualization of fuel freezing existed prior to the research presented in this dissertation. Consequently, computational fluid dynamics (CFD) modeling that simulates jet fuel freezing and model validation were incomplete prior to the present work. The ability to simulate jet fuel freezing is a necessary tool for fuel system designers. An additional impediment to the understanding and simulation of jet fuel freezing has been the absence of published low-temperature thermo-physical properties, including viscosity, which the present work addresses. The dissertation is subdivided into three major segments covering visualization, modeling and validation, and viscosity studies. In the first segment samples of jet fuel, JPTS, kerosene, Jet A and Jet A containing additives, were cooled below their freeze point temperatures in a rectangular, optical cell. Images and temperature data recorded during the solidification process provided information on crystal habit, crystallization behavior, and the influence of the buoyancy-driven flow on freezing. N-alkane composition of the samples was determined. The Jet A sample contained the least n-alkane mass. The cooling of JPTS resulted in the least wax formation while the cooling of kerosene yielded the greatest wax formation. The JPTS and kerosene samples exhibited similar crystallization behavior and crystal habits during

  14. The Longitudinal Properties of a Solar Energetic Particle Event Investigated Using Modern Solar Imaging

    Science.gov (United States)

    Rouillard, A. P.; Sheeley, N.R. Jr.; Tylka, A.; Vourlidas, A.; Ng, C. K.; Rakowski, C.; Cohen, C. M. S.; Mewaldt, R. A.; Mason, G. M.; Reames, D.; hide

    2012-01-01

    We use combined high-cadence, high-resolution, and multi-point imaging by the Solar-Terrestrial Relations Observatory (STEREO) and the Solar and Heliospheric Observatory to investigate the hour-long eruption of a fast and wide coronal mass ejection (CME) on 2011 March 21 when the twin STEREO spacecraft were located beyond the solar limbs. We analyze the relation between the eruption of the CME, the evolution of an Extreme Ultraviolet (EUV) wave, and the onset of a solar energetic particle (SEP) event measured in situ by the STEREO and near-Earth orbiting spacecraft. Combined ultraviolet and white-light images of the lower corona reveal that in an initial CME lateral "expansion phase," the EUV disturbance tracks the laterally expanding flanks of the CME, both moving parallel to the solar surface with speeds of approx 450 km/s. When the lateral expansion of the ejecta ceases, the EUV disturbance carries on propagating parallel to the solar surface but devolves rapidly into a less coherent structure. Multi-point tracking of the CME leading edge and the effects of the launched compression waves (e.g., pushed streamers) give anti-sunward speeds that initially exceed 900 km/s at all measured position angles. We combine our analysis of ultraviolet and white-light images with a comprehensive study of the velocity dispersion of energetic particles measured in situ by particle detectors located at STEREO-A (STA) and first Lagrange point (L1), to demonstrate that the delayed solar particle release times at STA and L1 are consistent with the time required (30-40 minutes) for the CME to perturb the corona over a wide range of longitudes. This study finds an association between the longitudinal extent of the perturbed corona (in EUV and white light) and the longitudinal extent of the SEP event in the heliosphere.

  15. Identification of Parton Pairs in a Dijet Event and Investigation of Its Effects on Dijet Resonance Search

    Directory of Open Access Journals (Sweden)

    Sertac Ozturk

    2014-01-01

    Full Text Available Being able to distinguish parton pair type in a dijet event could significantly improve the search for new particles that are predicted by the theories beyond the Standard Model at the Large Hadron Collider. To explore whether parton pair types manifesting themselves as a dijet event could be distinguished on an event-by-event basis, I performed a simulation based study considering observable jet variables. I found that using a multivariate approach can filter out about 80% of the other parton pairs while keeping more than half of the quark-quark or gluon-gluon parton pairs in an inclusive QCD dijet distribution. The effects of event-by-event parton pair tagging for dijet resonance searches were also investigated and I found that improvement on signal significance after applying parton pair tagging can reach up to 4 times for gluon-gluon resonances.

  16. Investigation of flameholding mechanisms in a kerosene-fueled scramjet combustor

    Science.gov (United States)

    Wang, Yu-hang; Song, Wen-yan; Shi, De-yong

    2017-11-01

    Laser-induced fluorescence and high-speed photography were employed to investigate the kerosene flame stabilization mechanism in a cavity-based scramjet combustor with an inlet condition corresponds to flight Mach number of 4. Pilot hydrogen was used to ignite the kerosene fuel. The PLIF results of kerosene distribution in the reacting cases showed that the mixing process was dramatically enhanced compared to the non-reacting cases. Sharp OH gradients were observed in the shear layer and the aft region of cavity, which indicated that the flame was located at these positions. A portion of hot products participated in the recirculation of the cavity and preheated the kerosene-air mixture in the leading edge. The heated mixture was ignited in the mid-cavity and the reaction zone spread into the mainstream flow. Due to the competition between the local flame speed and the local flow speed, the high-speed images showed that the spreading location was in fluctuation. This movement was observed to cause a low-frequency wall pressure fluctuation.

  17. AREVA NP burnup credit investigation on irradiated MOX fuel within the REBUS BWR programme

    Energy Technology Data Exchange (ETDEWEB)

    Alander, Alexandra; Misu, Stefan; Timm, Wolf [AREVA, AREVA NP, Erlangen (Germany); Thareau, Sebastien [AREVA, AREVA NP, Paris (France)

    2008-07-01

    The present paper summarizes a criticality and burnup credit investigation carried out using the 2D spectral codes CASMO-4 and APOLLO2-A. Fission rate distributions and multiplication factors, for UOX and MOX configurations, are calculated as well as the reactivity effect caused by burnup on a selection of irradiated MOX fuel assemblies. 3D core criticality calculations were carried out with the Monte Carlo transport code MOCA and the deterministic transport code VARIANT (a nodal code developed by ANL) using CASMO-4 generated cross section libraries. Calculations were compared to experimental data from the critical facility VENUS in the context of the REBUS BWR Programme. The results confirm that the spectral codes CASMO-4 and APOLLO2-A are well suited to calculate fission rates, multiplication factors and reactivity effects. It is also found that the calculated burnup reactivity effect, using CASMO-4 generated cross sections and the best 3D method (MOCA), is underestimated by merely 7% compared to the experimental value, which can mainly be attributed to the simplifications done in order to model the critical configurations with reasonable efforts. (authors)

  18. Experimental and numerical investigation of fuel mixing effects on soot structures in counterflow diffusion flames

    KAUST Repository

    Choi, Byungchul

    2011-03-26

    Experimental and numerical analyses of laminar diffusion flames were performed to identify the effect of fuel mixing on soot formation in a counterflow burner. In this experiment, the volume fraction, number density, and particle size of soot were investigated using light extinction/scattering systems. The experimental results showed that the synergistic effect of an ethylene-propane flame is appreciable. Numerical simulations showed that the benzene (C6H6) concentration in mixture flames was higher than in ethylene-base flames because of the increase in the concentration of propargyl radicals. Methyl radicals were found to play an important role in the formation of propargyl, and the recombination of propargyl with benzene was found to lead to an increase in the number density for cases exhibiting synergistic effects. These results imply that methyl radicals play an important role in soot formation, particularly with regard to the number density. © 2011 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.

  19. Compound-Specific Isotope Analysis of Diesel Fuels in a Forensic Investigation

    Directory of Open Access Journals (Sweden)

    Syahidah Akmal Muhammad

    2015-02-01

    Full Text Available Compound-specific isotope analysis (CSIA offers great potential as a tool to provide chemical evidence in a forensic investigation. Many attempts to trace environmental oil spills were successful where isotopic values were particularly distinct. However, difficulties arise when a large data set is analyzed and the isotopic differences between samples are subtle. In the present study, discrimination of diesel oils involved in a diesel theft case was carried out to infer the relatedness of the samples to potential source samples. This discriminatory analysis used a suite of hydrocarbon diagnostic indices, alkanes, to generate carbon and hydrogen isotopic data of the compositions of the compounds which were then processed using multivariate statistical analyses to infer the relatedness of the data set. The results from this analysis were put into context by comparing the data with the δ13C and δ2H of alkanes in commercial diesel samples obtained from various locations in the South Island of New Zealand. Based on the isotopic character of the alkanes, it is suggested that diesel fuels involved in the diesel theft case were distinguishable. This manuscript shows that CSIA when used in tandem with multivariate statistical analysis provide a defensible means to differentiate and source-apportion qualitatively similar oils at the molecular level. This approach was able to overcome confounding challenges posed by the near single-point source of origin i.e. the very subtle differences in isotopic values between the samples.

  20. Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Shenyang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burkes, Douglas E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Senor, David J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Setyawan, Wahyu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Zhijie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-07-08

    Nano-gas bubble superlattices are often observed in irradiated UMo nuclear fuels. However, the for- mation mechanism of gas bubble superlattices is not well understood. A number of physical processes may affect the gas bubble nucleation and growth; hence, the morphology of gas bubble microstructures including size and spatial distributions. In this work, a phase-field model integrating a first-passage Monte Carlo method to investigate the formation mechanism of gas bubble superlattices was devel- oped. Six physical processes are taken into account in the model: 1) heterogeneous generation of gas atoms, vacancies, and interstitials informed from atomistic simulations; 2) one-dimensional (1-D) migration of interstitials; 3) irradiation-induced dissolution of gas atoms; 4) recombination between vacancies and interstitials; 5) elastic interaction; and 6) heterogeneous nucleation of gas bubbles. We found that the elastic interaction doesn’t cause the gas bubble alignment, and fast 1-D migration of interstitials along $\\langle$110$\\rangle$ directions in the body-centered cubic U matrix causes the gas bubble alignment along $\\langle$110$\\rangle$ directions. It implies that 1-D interstitial migration along [110] direction should be the primary mechanism of a fcc gas bubble superlattice which is observed in bcc UMo alloys. Simulations also show that fission rates, saturated gas concentration, and elastic interaction all affect the morphology of gas bubble microstructures.

  1. Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Shenyang, E-mail: shenyang.hu@pnnl.gov; Burkes, Douglas E.; Lavender, Curt A.; Senor, David J.; Setyawan, Wahyu; Xu, Zhijie

    2016-10-15

    Nano-gas bubble superlattices are often observed in irradiated UMo nuclear fuels. However, the formation mechanism of gas bubble superlattices is not well understood. A number of physical processes may affect the gas bubble nucleation and growth; hence, the morphology of gas bubble microstructures including size and spatial distributions. In this work, a phase-field model integrating a first-passage Monte Carlo method to investigate the formation mechanism of gas bubble superlattices was developed. Six physical processes are taken into account in the model: 1) heterogeneous generation of gas atoms, vacancies, and interstitials informed from atomistic simulations; 2) one-dimensional (1-D) migration of interstitials; 3) irradiation-induced dissolution of gas atoms; 4) recombination between vacancies and interstitials; 5) elastic interaction; and 6) heterogeneous nucleation of gas bubbles. We found that the elastic interaction doesn’t cause the gas bubble alignment, and fast 1-D migration of interstitials along 〈110〉 directions in the body-centered cubic U matrix causes the gas bubble alignment along 〈110〉 directions. It implies that 1-D interstitial migration along [110] direction should be the primary mechanism of a fcc gas bubble superlattice which is observed in bcc UMo alloys. Simulations also show that fission rates, saturated gas concentration, and elastic interaction all affect the morphology of gas bubble microstructures.

  2. Understanding electricity generation in osmotic microbial fuel cells through integrated experimental investigation and mathematical modeling.

    Science.gov (United States)

    Qin, Mohan; Ping, Qingyun; Lu, Yaobin; Abu-Reesh, Ibrahim M; He, Zhen

    2015-11-01

    Osmotic microbial fuel cells (OsMFCs) are a new type of MFCs with integrating forward osmosis (FO). However, it is not well understood why electricity generation is improved in OsMFCs compared to regular MFCs. Herein, an approach integrating experimental investigation and mathematical model was adopted to address the question. Both an OsMFC and an MFC achieved similar organic removal efficiency, but the OsMFC generated higher current than the MFC with or without water flux, resulting from the lower resistance of FO membrane. Combining NaCl and glucose as a catholyte demonstrated that the catholyte conductivity affected the electricity generation in the OsMFC. A mathematical model of OsMFCs was developed and validated with the experimental data. The model predicated the variation of internal resistance with increasing water flux, and confirmed the importance of membrane resistance. Increasing water flux with higher catholyte conductivity could decrease the membrane resistance. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Hybrid direct carbon fuel cell anode processes investigated using a 3-electrode half-cell setup

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Arenillas, A.; Menendez, J.A.

    2015-01-01

    anthracite and bituminous coals, as well as carbon black, were tested, revealing similar open circuit potential and activation energies in mixed 96-4vol% N2-CO2 and 50-50vol% CO-CO2 environments between 700 and 800°C. Bituminous coal showed the highest activity, likely associated to a high O/C ratio......A 3-electrode half-cell setup consisting of a yttria-stabilized zirconia (YSZ) electrolyte support was employed to investigate the chemical and electrochemical processes occurring in the vicinity of a model hybrid direct carbon fuel cell (HDCFC) anode (Ni-YSZ) in contact with a molten carbon......-alkali carbonate slurry. Electrochemical testing, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), with and without the Ni-YSZ layer highlighted the promotional effect of the Ni-YSZ anode layer, and revealed the contributions of Ni/NiO, and potentially K/K2O, redox couple(s). Treated...

  4. Investigation of resided water effects on PEM fuel cell after cold start

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Junbo; Hao, Lixing; Song, Wei; Fu, Yu. [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian (China). Fuel Cell System and Engineering Laboratory; Graduate School of the Chinese Academy of Sciences, Beijing (China); Yi, Baolian; Yu, Hongmei; Shao, Zhigang [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian (China). Fuel Cell System and Engineering Laboratory

    2007-12-15

    The effects of the residual water in the PEM fuel cell after cold start on the performance, electrode electrochemical characteristics, and cell components were investigated by controlling the cold-start processes of three cells at -5 {sup circle} C. Neither the cell performance loss nor the cell resistance increase with the start number was observed. There was no change in the electrochemical active surface area (ECA) and charge transfer resistance at low current density. The correlation between the amount of the residual water and the ohmic polarization and cell resistance showed mass-transport process slightly changed with the water amount in the cell. This trend correlated well with the charge transfer resistance at high current density. The change of mass-transport process came from the gas diffusion layer by the analysis of ECA. It was found that hydrogen crossover rate of the membrane at the three hydrated states did not change through eight start-ups at -5 {sup circle} C. Based on the analysis of SEM and water-storage capacity, it was believed that less water was stored in the catalyst layer even though much water resided in the cell. (author)

  5. A micro-level event-centered approach to investigating armed conflict and population responses.

    Science.gov (United States)

    Williams, Nathalie E; Ghimire, Dirgha J; Axinn, William G; Jennings, Elyse A; Pradhan, Meeta S

    2012-11-01

    In this article, we construct and test a micro-level event-centered approach to the study of armed conflict and behavioral responses in the general population. Event-centered approaches have been successfully used in the macro-political study of armed conflict but have not yet been adopted in micro-behavioral studies. The micro-level event-centered approach that we advocate here includes decomposition of a conflict into discrete political and violent events, examination of the mechanisms through which they affect behavior, and consideration of differential risks within the population. We focus on two mechanisms: instability and threat of harm. We test this approach empirically in the context of the recent decade-long armed conflict in Nepal, using detailed measurements of conflict-related events and a longitudinal study of first migration, first marriage, and first contraceptive use. Results demonstrate that different conflict-related events independently shaped migration, marriage, and childbearing and that they can simultaneously influence behaviors in opposing directions. We find that violent events increased migration, but political events slowed migration. Both violent and political events increased marriage and contraceptive use net of migration. Overall, this micro-level event-centered approach yields a significant advance for the study of how armed conflict affects civilian behavioral responses.

  6. Impact investigation of reactor fuel operating parameters on reactivity for use in burnup credit applications

    Science.gov (United States)

    Sloma, Tanya Noel

    When representing the behavior of commercial spent nuclear fuel (SNF), credit is sought for the reduced reactivity associated with the net depletion of fissile isotopes and the creation of neutron-absorbing isotopes, a process that begins when a commercial nuclear reactor is first operated at power. Burnup credit accounts for the reduced reactivity potential of a fuel assembly and varies with the fuel burnup, cooling time, and the initial enrichment of fissile material in the fuel. With regard to long-term SNF disposal and transportation, tremendous benefits, such as increased capacity, flexibility of design and system operations, and reduced overall costs, provide an incentive to seek burnup credit for criticality safety evaluations. The Nuclear Regulatory Commission issued Interim Staff Guidance 8, Revision 2 in 2002, endorsing burnup credit of actinide composition changes only; credit due to actinides encompasses approximately 30% of exiting pressurized water reactor SNF inventory and could potentially be increased to 90% if fission product credit were accepted. However, one significant issue for utilizing full burnup credit, compensating for actinide and fission product composition changes, is establishing a set of depletion parameters that produce an adequately conservative representation of the fuel's isotopic inventory. Depletion parameters can have a significant effect on the isotopic inventory of the fuel, and thus the residual reactivity. This research seeks to quantify the reactivity impact on a system from dominant depletion parameters (i.e., fuel temperature, moderator density, burnable poison rod, burnable poison rod history, and soluble boron concentration). Bounding depletion parameters were developed by statistical evaluation of a database containing reactor operating histories. The database was generated from summary reports of commercial reactor criticality data. Through depletion calculations, utilizing the SCALE 6 code package, several light

  7. Investigation of Meteorological Extreme Events in the North-East of Iran

    Directory of Open Access Journals (Sweden)

    S. Kouzegaran

    2016-02-01

    Full Text Available Introduction: Over the past hundred years, human activity has significantly altered the atmosphere and increase of concentration of greenhouse gases lead to warm the earth's surface. This global warming leads to change of climatic extreme index and increases the intensity and frequency of occurrence of extreme climate events. Investigation of extreme values for planning and policy for the agricultural sector and water resource management is important.In this study, a comprehensive review of extreme indices of temperature and precipitation are discussed. This paper aims to investigate extreme temperature and precipitation indices defined in accordance with CCL, and the study of other climatic parameters in the North East of Iran. Materials and Methods: In this research, statistics and data of some stations in the North East of Iran during the period 1992-2012 were used. To evaluate the extreme climate indices trend, 27 indices of rainfall and temperature, were defined by the ETCCDMI. They were calculated by RClimdex software. In this software, prior to the index calculation, data by quality control software became quantitative and incorrect data were controlled and outlier data were examined. The indices were calculated by daily data. 11 rainfall and 16 temperature indices were calculated by this software.The target of the ETCCDMI process is to delineate a standardized set of indices allowing for comparison across regions. These extreme indices were classified in five categories which included the percentile-based extreme indices, the absolute extreme indices, the threshold extreme indices, the periodic extreme indices, and the other indices. They were estimated at the 0.05 significant levels. The Mann-Kendall test was used to investigate the climatic parameters, maximum relative humidity, sunshine duration and maximum wind speed. Results and Discussion: Thermal analysis results are consistent with warming patterns, and they have showed that hot

  8. Corrective Action Investigation Plan for Corrective Action Unit 321: Area 22 Weather Station Fuel Storage, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    DOE/NV

    1999-01-28

    This Corrective Action Investigation Plan (CAIP) has been developed in accordance with the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the US Department of Energy, Nevada Operations Office (DOE/NV); the State of Nevada Division of Environmental Protection (NDEP); and the US Department of Defense (FFACO, 1996). The CAIP is a document that provides or references all of the specific information for investigation activities associated with Corrective Action Units (CAUs) or Corrective Action Sites (CASs). According to the FFACO (1996), CASs are sites potentially requiring corrective action(s) and may include solid waste management units or individual disposal or release sites. A CAU consists of one or more CASs grouped together based on geography, technical similarity, or agency responsibility for the purpose of determining corrective actions. This CAIP contains the environmental sample collection objectives and the criteria for conducting site investigation activities at the CAU 321 Area 22 Weather Station Fuel Storage, CAS 22-99-05 Fuel Storage Area. For purposes of this discussion, this site will be referred to as either CAU 321 or the Fuel Storage Area. The Fuel Storage Area is located in Area 22 of the Nevada Test Site (NTS). The NTS is approximately 105 kilometers (km) (65 miles [mi]) northwest of Las Vegas, Nevada (Figure 1-1) (DOE/NV, 1996a). The Fuel Storage Area (Figure 1-2) was used to store fuel and other petroleum products necessary for motorized operations at the historic Camp Desert Rock facility which was operational from 1951 to 1958 at the Nevada Test Site, Nevada. The site was dismantled after 1958 (DOE/NV, 1996a).

  9. AN INVESTIGATION TO RESOLVE THE INTERACTION BETWEEN FUEL CELL, POWER CONDITIONING SYSTEM AND APPLICATION LOADS

    Energy Technology Data Exchange (ETDEWEB)

    Sudip K. Mazumder; Chuck McKintyre; Dan Herbison; Doug Nelson; Comas Haynes; Michael von Spakovsky; Joseph Hartvigsen; S. Elangovan

    2003-11-03

    Solid-Oxide Fuel Cell (SOFC) stacks respond quickly to changes in load and exhibit high part- and full-load efficiencies due to its rapid electrochemistry. However, this is not true for the thermal, mechanical, and chemical balance-of-plant subsystem (BOPS), where load-following time constants are, typically, several orders of magnitude higher. This dichotomy diminishes the reliability and performance of the electrode with increasing demand of load. Because these unwanted phenomena are not well understood, the manufacturers of SOFC use conservative schemes (such as, delayed load-following to compensate for slow BOPS response or expensive inductor filtering) to control stack responses to load variations. This limits the applicability of SOFC systems for load-varying stationary and transportation applications from a cost standpoint. Thus, a need exists for the synthesis of component- and system-level models of SOFC power-conditioning systems and the development of methodologies for investigating the system-interaction issues (which reduce the lifetime and efficiency of a SOFC) and optimizing the responses of each subsystem, leading to optimal designs of power-conditioning electronics and optimal control strategies, which mitigate the electrical-feedback effects. Equally important are ''multiresolution'' finite-element modeling and simulation studies, which can predict the impact of changes in system-level variables (e.g., current ripple and load-transients) on the local current densities, voltages, and temperature (these parameters are very difficult or cumbersome, if not impossible to obtain) within a SOFC cell. Towards that end, for phase I of this project, sponsored by the U.S. DOE (NETL), we investigate the interactions among fuel cell, power-conditioning system, and application loads and their effects on SOFC reliability (durability) and performance. A number of methodologies have been used in Phase I to develop the steady-state and transient

  10. Adhesion and migration to the differentiated levels of corporate governance: an investigation of the event window

    Directory of Open Access Journals (Sweden)

    Ricardo Adriano Antonelli

    2016-04-01

    Full Text Available Even though many researchers use event study methodology, these studies commonly diverge in terms of the length of window considered and of findings. The definition of the event window is essential, but it always involves a certain degree of subjectivity and arbitrariness. In order to establish objective bases for delimiting the event window, a methodology is proposed based on the results of analysis of 75 cases of companies that have adhered or migrated to the differentiated levels of corporate governance (NDGC of BM&FBovespa. These results reveal the great importance of small event windows, because in 47 cases out of 75 windows of five trading sessions before and five after the event (5-5 were observed. This indicates that the use of large event windows to capture and measure the effects of adhesion or migration to the NDGC, although frequent, may be misleading.

  11. INVESTIGATION OF FUEL CHEMISTRY AND BED PERFORMANCE IN A FLUIDIZED BED BLACK LIQUOR STEAM REFORMER

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Whitty

    2003-12-01

    The University of Utah project ''Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer'' (DOE award number DE-FC26-02NT41490) was developed in response to a solicitation for projects to provide technical support for black liquor and biomass gasification. The primary focus of the project is to provide support for a DOE-sponsored demonstration of MTCI's black liquor steam reforming technology at Georgia-Pacific's paper mill in Big Island, Virginia. A more overarching goal is to improve the understanding of phenomena that take place during low temperature black liquor gasification. This is achieved through five complementary technical tasks: (1) construction of a fluidized bed black liquor gasification test system, (2) investigation of bed performance, (3) evaluation of product gas quality, (4) black liquor conversion analysis and modeling and (5) computational modeling of the Big Island gasifier. Four experimental devices have been constructed under this project. The largest facility, which is the heart of the experimental effort, is a pressurized fluidized bed gasification test system. The system is designed to be able to reproduce conditions near the black liquor injectors in the Big Island steam reformer, so the behavior of black liquor pyrolysis and char gasification can be quantified in a representative environment. The gasification test system comprises five subsystems: steam generation and superheating, black liquor feed, fluidized bed reactor, afterburner for syngas combustion and a flue gas cooler/condenser. The three-story system is located at University of Utah's Industrial Combustion and Gasification Research Facility, and all resources there are available to support the research.

  12. An Investigation to Resolve the Interaction Between Fuel Cell, Power Conditioning System and Application Loads

    Energy Technology Data Exchange (ETDEWEB)

    Sudip K. Mazumder

    2005-12-31

    Development of high-performance and durable solidoxide fuel cells (SOFCs) and a SOFC power-generating system requires knowledge of the feedback effects from the power-conditioning electronics and from application-electrical-power circuits that may pass through or excite the power-electronics subsystem (PES). Therefore, it is important to develop analytical models and methodologies, which can be used to investigate and mitigate the effects of the electrical feedbacks from the PES and the application loads (ALs) on the reliability and performance of SOFC systems for stationary and non-stationary applications. However, any such attempt to resolve the electrical impacts of the PES on the SOFC would be incomplete unless one utilizes a comprehensive analysis, which takes into account the interactions of SOFC, PES, balance-of-plant system (BOPS), and ALs as a whole. SOFCs respond quickly to changes in load and exhibit high part- and full-load efficiencies due to its rapid electrochemistry, which is not true for the thermal and mechanical time constants of the BOPS, where load-following time constants are, typically, several orders of magnitude higher. This dichotomy can affect the lifetime and durability of the SOFCSs and limit the applicability of SOFC systems for load-varying stationary and transportation applications. Furthermore, without validated analytical models and investigative design and optimization methodologies, realizations of cost-effective, reliable, and optimal PESs (and power-management controls), in particular, and SOFC systems, in general, are difficult. On the whole, the research effort can lead to (a) cost-constrained optimal PES design for high-performance SOFCS and high energy efficiency and power density, (b) effective SOFC power-system design, analyses, and optimization, and (c) controllers and modulation schemes for mitigation of electrical impacts and wider-stability margin and enhanced system efficiency.

  13. Investigating the effects of methanol-water vapor mixture on a PBI-based high temperature PEM fuel cell

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Andreasen, Søren Juhl; Nielsen, Heidi Venstrup

    2012-01-01

    This paper investigates the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC). A H3PO4-doped polybenzimidazole (PBI) membrane electrode assembly (MEA), Celtec P2100 of 45 cm2 of active surface area from BASF was employed....... A long-term durability test of around 1250 h was performed, in which the concentrations of methanol-water vapor mixture in the anode feed gas were varied. The fuel cell showed a continuous performance decay in the presence of vapor mixtures of methanol and water of 5% and 8% by volume in anode feed...

  14. A Micro-Level Event-Centered Approach to Investigating Armed Conflict and Population Responses

    OpenAIRE

    Williams, Nathalie E.; Ghimire, Dirgha J.; Axinn, William G.; Jennings, Elyse A.; Pradhan, Meeta S.

    2012-01-01

    In this article, we construct and test a micro-level event-centered approach to the study of armed conflict and behavioral responses in the general population. Event-centered approaches have been successfully used in the macro-political study of armed conflict but have not yet been adopted in micro-behavioral studies. The micro-level event-centered approach that we advocate here includes decomposition of a conflict into discrete political and violent events, examination of the mechanisms thro...

  15. Resolving the orthographic ambiguity during visual word recognition in Arabic: an event-related potential investigation

    Science.gov (United States)

    Taha, Haitham; Khateb, Asaid

    2013-01-01

    The Arabic alphabetical orthographic system has various unique features that include the existence of emphatic phonemic letters. These represent several pairs of letters that share a phonological similarity and use the same parts of the articulation system. The phonological and articulatory similarities between these letters lead to spelling errors where the subject tends to produce a pseudohomophone (PHw) instead of the correct word. Here, we investigated whether or not the unique orthographic features of the written Arabic words modulate early orthographic processes. For this purpose, we analyzed event-related potentials (ERPs) collected from adult skilled readers during an orthographic decision task on real words and their corresponding PHw. The subjects' reaction times (RTs) were faster in words than in PHw. ERPs analysis revealed significant response differences between words and the PHw starting during the N170 and extending to the P2 component, with no difference during processing steps devoted to phonological and lexico-semantic processing. Amplitude and latency differences were found also during the P6 component which peaked earlier for words and where source localization indicated the involvement of the classical left language areas. Our findings replicate some of the previous findings on PHw processing and extend them to involve early orthographical processes. PMID:24348367

  16. Control of Fuel Microorganisms with Magnetic Devices: Laboratory Investigation with Hormoconis Resinae

    Science.gov (United States)

    1991-11-01

    Aircraft Materials Technical Memorandum 408 CONTROL OF FUEL MICROORGANISMS WITH MAGNETIC DEVICES: LABORATORY INN, ESTIGATION WITH HORMOCONIS RESINAE ... RESINAE by G.G. McVEA R.K. SOLLY SUMMARY Automotive diesel fuel inoculated with the fungus, Hornoconis resinae , wascirculated through a magnetic device...HORMOCONIS resinae (often known by its previous name of Cladosporium resinae ) forms mats of slimy mycelia matter, which has a very high propensity to

  17. Experimental and numerical investigation on the ignition and combustion stability in solid fuel ramjet with swirling flow

    Science.gov (United States)

    Musa, Omer; Xiong, Chen; Changsheng, Zhou

    2017-08-01

    The present article investigates experimentally and numerically the ignition and flame stability of high-density polyethylene solid fuel with incoming swirling air through a solid fuel ramjet (SFRJ). A new design of swirler is proposed and used in this work. Experiments on connected pipes test facility were performed for SFRJ with and without swirl. An in-house code has been developed to simulate unsteady, turbulent, reacting, swirling flow in the SFRJ. Four different swirl intensities are utilized to study experimentally and numerically the effect of swirl number on the transient regression, ignition of the solid fuel in a hot-oxidizing flow and combustion phenomenon in the SFRJ. The results showed that using swirl flow decreases the ignition time delay, recirculation zone length, and the distance between the flame and the wall, meanwhile, increases the residence time, heat transfer, regression rate and mixing degree, thus, improving the combustion efficiency and stability.

  18. Experimental Investigation of Two Modified Chemicallooping Compustion Cycles Using Syngas from Cylindersand the Gasification of Solid Fuels

    Science.gov (United States)

    Müller, C. R.; Brown, T. A.; Bohn, C. D.; Chuang, S. Y.; Cleeton, J. P. E.; Scott, S. A.; Dennis, J. S.

    Two modified Chemical Looping Combustion (CLC) schemes were investigated: (a) CLC with in situ gasification of a solid carbonaceous fuel in the fuel reactor, and (b) CLC for the production of high purity hydrogen from low grade syngas. A comparison between the performance of the two modified cycles using (i) syngas from cylinders and (ii) syngas derived from the gasification of various solid fuels was made. Preliminary results indicate that both processes can be operated with sufficient conversions using low and high-rank coals. However, agglomeration of the oxygen carrier was observed if wood was used in process (a), probably owing to the formation of low-melting eutectics between the oxygen carrier and metals from the wood ash.

  19. Impact of Aviation Fuel Quality on Flight Safety and Environment

    OpenAIRE

    A.V. Yakovleva; S.V. Boichenko; O.A. Vovk

    2013-01-01

    The role of aviation fuels quality for provision of flight safety is described. Statistics on jet fuel consumption all over the world and Ukraine in particular is presented. Analysis of flight accidents is done; the role of fuel quality as a reason of such events as well as a factor affecting the environment is investigated.

  20. Nuclear magnetic resonance spectroscopic investigation of anode exhaust of direct methanol fuel cells without isotope enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Young Seok; Hwang, Reo Yun; Han, Ochee [Western Seoul Center, Korea Basic Science Institute, Seoul (Korea, Republic of)

    2016-12-15

    Fuel cells are devices that electrochemically convert the chemical energy of fuels such as natural gas, gasoline, and methanol, into electricity. Fuel cells more efficiently use energy than internal combustion engines and do not produce undesirable pollutants, such as NO{sub x} ,SO{sub x} and particulates. Fuel cells can be distinguished from one another by their electrolytes. Among the various direct alcohol fuel cells, direct methanol fuel cells (DMFCs) have been developed most. However, DMFCs have several practical problems such as methanol crossove r from an anode to a cathode and slow methanol oxidation reaction rates. Therefore, understanding the electrochemical reaction mechanisms of DMFCs may provide clues to solve these problems, and various analytical methods have been employed to examine these mechanisms. We demonstrated that {sup 1}H and {sup 13}C NMR spectroscopy can be used for analyzing anode exhausts of DMFCs operated with methanol without any isotope enrichment. However, the low sensitivity of NMR spectroscopy hindered our efforts to detect minor reaction intermediates. Therefore, sensitivity enhancement techniques such as dynamic nuclear polarization (DNP) NMR methods and/or presaturation methods to increase the dynamic range of the proton spectra by pre-saturating large water signals, are expected to be useful to detect low-concentration species.

  1. Numerical and Experimental Investigation of Combustion and Knock in a Dual Fuel Gas/Diesel Compression Ignition Engine

    Directory of Open Access Journals (Sweden)

    A. Gharehghani

    2012-01-01

    Full Text Available Conventional compression ignition engines can easily be converted to a dual fuel mode of operation using natural gas as main fuel and diesel oil injection as pilot to initiate the combustion. At the same time, it is possible to increase the output power by increasing the diesel oil percentage. A detailed performance and combustion characteristic analysis of a heavy duty diesel engine has been studied in dual fuel mode of operation where natural gas is used as the main fuel and diesel oil as pilot. The influence of intake pressure and temperature on knock occurrence and the effects of initial swirl ratio on heat release rate, temperature-pressure and emission levels have been investigated in this study. It is shown that an increase in the initial swirl ratio lengthens the delay period for auto-ignition and extends the combustion period while it reduces NOx. There is an optimum value of the initial swirl ratio for a certain mixture intake temperature and pressure conditions that can achieve high thermal efficiency and low NOx emissions while decreases the tendency to knock. Simultaneous increase of intake pressure and initial swirl ratio could be the solution to power loss and knock in dual fuel engine.

  2. Going for gold : Investigating the (non)sense of increased advertising around major sports events

    NARCIS (Netherlands)

    Gijsenberg, Maarten J.

    Major sports events draw unsurpassed media attention. Companies are motivated to increase their advertising investments around these events to reach large audiences in a short period. Is such an advertising surge actually beneficial though, or should companies avoid advertising in these periods

  3. Installation Restoration Program Phase 2. Confirmation/Quantification Stage 2. Bulk Fuel Storage Area Fuel Spill Investigation.

    Science.gov (United States)

    1987-10-01

    fire training areas for a government facility in Arizona. Hydrogeologie investigation for a scrap recovery facility in western Pennsylvania...V l3 c’ 1 >-v 1 * i si + 1 §i ? I • 5 o u • • a 1 1 tit j i j 9 J 1 CO z o CO | < Ö w a co 1 a • n

  4. Investigation and Taguchi Optimization of Microbial Fuel Cell Salt Bridge Dimensional Parameters

    Science.gov (United States)

    Sarma, Dhrupad; Barua, Parimal Bakul; Dey, Nabendu; Nath, Sumitro; Thakuria, Mrinmay; Mallick, Synthia

    2018-01-01

    One major problem of two chamber salt bridge microbial fuel cells (MFCs) is the high resistance offered by the salt bridge to anion flow. Many researchers who have studied and optimized various parameters related to salt bridge MFC, have not shed much light on the effect of salt bridge dimensional parameters on the MFC performance. Therefore, the main objective of this research is to investigate the effect of length and cross sectional area of salt bridge and the effect of solar radiation and atmospheric temperature on MFC current output. An experiment has been designed using Taguchi L9 orthogonal array, taking length and cross sectional area of salt bridge as factors having three levels. Nine MFCs were fabricated as per the nine trial conditions. Trials were conducted for 3 days and output current of each of the MFCs along with solar insolation and atmospheric temperature were recorded. Analysis of variance shows that salt bridge length has significant effect both on mean (with 53.90% contribution at 95% CL) and variance (with 56.46% contribution at 87% CL), whereas the effect of cross sectional area of the salt bridge and the interaction of these two factors is significant on mean only (with 95% CL). Optimum combination was found at 260 mm salt bridge length and 506.7 mm2 cross sectional area with 4.75 mA of mean output current. The temperature and solar insolation data when correlated with each of the MFCs average output current, revealed that both external factors have significant impact on MFC current output but the correlation coefficient varies from MFC to MFC depending on salt bridge dimensional parameters.

  5. A methodology for investigating new nonprecious metal catalysts for PEM fuel cells.

    Science.gov (United States)

    Susac, D; Sode, A; Zhu, L; Wong, P C; Teo, M; Bizzotto, D; Mitchell, K A R; Parsons, R R; Campbell, S A

    2006-06-08

    This paper reports an approach to investigate metal-chalcogen materials as catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells. The methodology is illustrated with reference to Co-Se thin films prepared by magnetron sputtering onto a glassy-carbon substrate. Scanning Auger microscopy (SAM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) have been used, in parallel with electrochemical activity and stability measurements, to assess how the electrochemical performance relates to chemical composition. It is shown that Co-Se thin films with varying Se are active for oxygen reduction, although the open circuit potential (OCP) is lower than for Pt. A kinetically controlled process is observed in the potential range 0.5-0.7 V (vs reversible hydrogen electrode) for the thin-film catalysts studied. An initial exposure of the thin-film samples to an acid environment served as a pretreatment, which modified surface composition prior to activity measurements with the rotating disk electrode (RDE) method. Based on the SAM characterization before and after electrochemical tests, all surfaces demonstrating activity are dominated by chalcogen. XRD shows that the thin films have nanocrystalline character that is based on a Co(1-x)Se phase. Parallel studies on Co-Se powder supported on XC72R carbon show comparable OCP, Tafel region, and structural phase as for the thin-film model catalysts. A comparison for ORR activity has also been made between this Co-Se powder and a commercial Pt catalyst.

  6. Investigation of Coal Fueled Chemical Looping Combustion Using Fe3O4 as Oxygen Carrier

    Science.gov (United States)

    Xlang, Wenguo; Sun, Xiaoyan; Wangt, Sha; Tian, Wendong; Xu, Xiang; Xu, Yanji; Xiao, Yunhan

    Chemical-looping combustion (CLC) is a novel combustion technique with CO2 separation. Magnetite (Fe3O4) was selected as the oxygen carrier and Shenhua coal (Inner Mongolia, China) as the fuel for this study. The influences of operation temperatures, and coal to Fe3O4 mass ratios on the reduction characteristics of the oxygen carrier were investigated using an atmosphere TGA. The sample, comprised of 2.25mg coal and 12.75mg Fe3O4, was heated to 1000°C. Experimental results show that the reaction between the coal volatile and Fe3O4 began at 700°C while the reaction between the coal char and Fe3O4 occurred at 800°C and reached a peak at 900°C. Fe3O4 was fully reduced into FeO, while some FeO was further reduced to Fe. As the operation temperature rises, the reduction conversion rate increases. At the temperatures of 850°C, 900°C, and 950°C, the reduction conversion rates were 37.1%, 46.5%, and 54.1% respectively. When the mass ratios of coal to Fe3O4 were 5/95, 10/90, 15/85, and 20/80, the reduction conversion rates were 29.5%,40.8%,46.5%, and 46.6% respectively. With the increase of coal to Fe3O4 mass ratio, the conversion rate increases first and then changes no more. There exists an optimal coal to Fe3O4 mass ratio.

  7. Numerical Investigation of a Gasoline-Like Fuel in a Heavy-Duty Compression Ignition Engine Using Global Sensitivity Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Pinaki; Probst, Daniel; Pei, Yuanjiang; Zhang, Yu; Traver, Michael; Cleary, David; Som, Sibendu

    2017-03-28

    significant impact on each target. The results were further assessed by investigating the impact of individual parameter variations on the targets. Overall, it was demonstrated that GSA can be an effective tool in understanding parameters sensitive to a low temperature combustion concept with novel fuels.

  8. Investigating Large Igneous Province Formation and Associated Paleoenvironmental Events: A White Paper for Scientific Drilling

    Directory of Open Access Journals (Sweden)

    Michael R. Rampino

    2008-07-01

    Full Text Available Earth’s history has been punctuated over at least the last 3.5 billion years by massive volcanism on a scale unknown in the recent geological past. Largely unknown mechanical and dynamic processes, with unclear relationships to seafloor spreading and subduction, generated voluminous, predominately mafic magmas that were emplaced into the Earth’s lithosphere. The resultant large igneous provinces (LIPs; Coffin and Eldholm, 1994; Ernst and Buchan, 2001; Bryan and Ernst, 2008 were at times accompanied by catastrophic environmental changes. The interaction of the LIP-associated mantle processes with the Earth’s crust have produced a variety of surface expressions (Fig. 1a and 1b; the most common present-day examples are oceanic plateaus (e.g., Kerguelen/Broken Ridge, Ontong Java, Manihiki, Hikurangi, Shatsky, ocean basin flood basalts (e.g., Caribbean, Nauru, magma-dominated divergent continental margins (e.g., theNorth Atlantic, and continental flood basalts (e.g., Columbia River, Deccan Traps, Siberian Traps. Environmental effects associated with LIP formation include climate changes, mass and other extinctions, variations in ocean and atmospheric chemistry, and Oceanic Anoxic Events (OAEs. Therefore, the geodynamic processes in the mantle that produce LIPs have potentially profoundly affected the Earth’s environment, particularly the biosphere and climate. The IntegratedOcean Drilling Program (IODP affords unique opportunities to investigate LIPs and associated environmental effects, building upon results from the Ocean Drilling Program (ODP and Deep Sea Drilling Project (DSDP (Coffin et al., 2006. To this end, a workshop on LIPs, sponsored by IODP Management International (IODP-MI and the Consortium for Ocean Leadership, was held at the University of Ulster in Coleraine, Northern Ireland, U.K. on 22–25 July 2007 (Coffinet al., 2007.

  9. Experimental Investigations Of The Influence Of Pressure On Critical Extinction Conditions Of Laminar Nonpremixed Flames Burning Condensed Hydrocarbon Fuels, Jet Fuels, And Surrogates

    Science.gov (United States)

    2014-10-25

    model combustion of practical fuels at high pressures. Commercial fuels, including jet fuels, kerosene, gasoline, and diesel , are composed of hundreds...the experimental testing of fuels with high boiling points for which it is difficult to avoid pyrolysis reactions during fuel vaporization [22]. Figure...flame as well as stabi- lize it. Product gases are cooled using fine water sprays within the burner body, then separated from the cooling water in a

  10. Investigating the mechanical and barrier properties to oxygen and fuel of high density polyethylene–graphene nanoplatelet composites

    Energy Technology Data Exchange (ETDEWEB)

    Honaker, K., E-mail: honakers@egr.msu.edu; Vautard, F.; Drzal, L.T.

    2017-02-15

    Highlights: • Melt mixing used to investigate high density polyethylene and graphene nanoplatelet composite. • Addition of graphene nanoplatelets resulted in a stiffer polymer matrix. • Presence of graphene nanoplatelets causes a decrease in oxygen and fuel permeation. - Abstract: Graphene nanoplatelets (GnP) of different sizes were investigated for their ability to modify high density polyethylene (HDPE) for potential fuel system applications, focusing on compounding via melt mixing in a twin-screw extruder. Mechanical properties, crystallinity of the polymer, and permeation to oxygen and fuel were assessed as a function of GnP concentration. The surface of GnP acted as a nucleation site for the generation of HDPE crystallites, increasing the crystallinity. The flexural properties were improved, clearly influenced by platelet size and quality of dispersion. A sharp, 46% decrease of the impact resistance was observed, even at low GnP concentration (0.2 wt.%). With a 15 wt.% GnP-M-15 (platelets with a 15 μm diameter), a 73% reduction in oxygen permeation was observed and a 74% reduction in fuel vapor transmission. This correlation was similar throughout the GnP concentration range. The smaller diameter platelets had a lesser effect on the properties.

  11. Experimental investigation and numerical comparison of the performance of a proton exchange membrane fuel cell at different channel geometry

    Science.gov (United States)

    Khazaee, I.

    2015-08-01

    In this study, the performance of a PEM fuel cell is investigated experimentally and numerically by changing the geometry of the channels. At first an experimental setup is used and three different fuel cells with rectangular, elliptical and triangular serpentine channels are constructed. The active area of each cell is 25 cm2 that its weight is 1,300 g. The material of the gas diffusion layer is carbon clothes, the membrane is nafion 117 and the catalyst layer is a plane with 0.004 g cm-2 platinum. Then a complete three-dimensional model for fuel cell is used to investigate the effect of using this channels geometry on the performance. The proposed model is a full cell model, which includes all the parts of the PEM fuel cell, flow channels, gas diffusion electrodes, catalyst layers and the membrane. Coupled transport and electrochemical kinetics equations are solved in a single domain; therefore no interfacial boundary condition is required at the internal boundaries between cell components. The results show that the predicted polarization curves by using this model are in good agreement with the experimental results. Also the results show that when the geometry of channel is rectangular the performance of the cell is better than the triangular and elliptical channel.

  12. Investigations on burning efficiency and exhaust emission of in-line type emulsified fuel system

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, Y.K. [National Chinyi University of Technology (Taiwan). Dept. of Mechanical Engineering; Cheng, H.C. [Point Environmental Protection Technology Company Limited (Taiwan)

    2011-07-28

    In this research, the burning efficiency as well as exhaust emission of a new water-in-oil emulsified fuel system was studied. This emulsified system contains two core processes, the first one is to mix 97% water with 3% emulsifier by volume, and get the milk-like emulsified liquid, while the second one is to compound the milk-like emulsified liquid with heavy oil then obtain the emulsified fuel. In order to overcome the used demulsification problem during in reserve or in transport, this system was designed as a made and use in-line type. From the results of a series of burning tests, the fuel saving can be 8--15%. Also, from the comparison of decline for the heat value and total energy output of emulsified fuel, one can find that the water as the dispersed phase in the combustion process will lead to a micro-explosion as well as the water gas effect, both can raise the combustion temperature and burning efficiency. By comparing the waste gas emission of different types of emulsified fuel, one can know that, the CO2 emission reduces approximately 14%, and NOx emission reduces above 46%, meaning the reduction of the exhaust gas is truly effective. From the exhaust temperature of tail pipe, the waste heat discharge also may reduce 27%, it is quite advantageous to the global warming as well as earth environmental protection.

  13. Experimental Investigation of Performance of a Miniature Direct Methanol Fuel Cell in Short-Term Microgravity

    Science.gov (United States)

    Ye, Fang; Wu, Feng; Zhao, Jian Fu; Guo, Hang; Wan, Shi Xin; Lv, Cui Ping; Ma, Chong Fang

    2010-09-01

    Experimental study of a liquid fed direct methanol fuel cell has been conducted in different gravity environments. A small single cell with 5 cm × 5 cm active area has single serpentine channel on the graphite cathode polar plate and 11 parallel straight channels on the graphite anode flow bed. Cell voltage and current have been measured and two-phase flow in anode channels has been in situ visually observed. The experimental results indicate that the effect of gravity on power performance of the direct methanol fuel cell is large when the concentration polarization governs fuel cells operation. Gravitational effect becomes larger at higher current density. Increasing methanol feeding molarity is conducive to weaken the influence of gravity on performance of liquid fed direct methanol fuel cells. Increasing feeding flow rate of methanol solution from 6 to 15 ml/min could reduce the size of carbon dioxide bubbles, while the influence of gravity still exist. Transport phenomena inside direct methanol fuel cells in microgravity is also analyzed and discussed.

  14. Experimental investigations of a four-stroke single cylinder direct injection diesel engine operated on dual fuel mode with producer gas as inducted fuel and Honge oil and its methyl ester (HOME) as injected fuels

    Energy Technology Data Exchange (ETDEWEB)

    Banapurmath, N.R.; Tewari, P.G. [Department of Mechanical Engineering, B.V.B. College of Engineering and Technology, Hubli 580031, Karnataka (India); Hosmath, R.S. [Department of Mechanical Engineering, K.L.E Society' s College of Engineering and Technology, Belgaum, Karnataka (India)

    2008-09-15

    In order to meet the energy requirements, there has been growing interest in alternative fuels like biodiesels, methyl alcohol, ethyl alcohol, biogas, hydrogen and producer gas to provide a suitable diesel oil substitute for internal combustion engines. Vegetable oils present a very promising alternative to diesel oil since they are renewable and have similar properties. Vegetable oils offer almost the same power output with slightly lower thermal efficiency when used in diesel engine [Srivastava A, Prasad R. Triglycerides-based diesel fuels. Renew Sustain Energy Rev 2000;4:111-33.; Vellguth G. Performance of vegetable oils and their monoesters as fuels for diesel engines. SAE 831358, 1983.; Demirbas A. Biodiesel production from vegetable oils via catalytic and non-catalytic supercritical methanol transesterification methods. Int J Prog Energy Combust Sci 2005;31:466-87.; Jajoo BN, Keoti RS. Evaluation of vegetable oils as supplementary fuels for diesel engines. In: Proceedings of the XV national conference on IC engines and combustion, Anna University Chennai, 1997.; Altin R, Cetinkaya S, Yucesu HS. The potential of using vegetable oil fuels as fuel for diesel engines. Int J Energy Convers Manage 2000;42:529-38, 248.; Gajendra Babu MK, Chandan Kumar Das LM. Experimental investigations on a Karanja oil methyl ester fuelled DI diesel engine. SAE 2006-01-0238, 2006.; Agarwal D, Kumar Agarwal A. Performance and emission characteristics of a Jatropha oil (preheated and blends) in a direct injection compression ignition engine. Int J Appl Therm Eng 2007;27:2314-23. ]. Research in this direction with edible oils have yielded encouraging results, but their use as fuel for diesel engine has limited applications due to higher domestic requirement [Scholl Kyle W, Sorenson Spencer C. Combustion Analysis of soyabean oil methyl ester in a direct injection diesel engine. SAE 930934, 1993.; Nwafor OMI. Effect of advanced injection timing on the performance of rapeseed oil in

  15. Investigations of ash fouling with cattle wastes as reburn fuel in a small-scale boiler burner under transient conditions.

    Science.gov (United States)

    Oh, Hyukjin; Annamalai, Kalyan; Sweeten, John M

    2008-04-01

    Fouling behavior under reburn conditions was investigated with cattle wastes (termed as feedlot biomass [FB]) and coal as reburn fuels under a transient condition and short-time operation. A small-scale (30 kW or 100,000 Btu/hr) boiler burner research facility was used for the reburn experiments. The fuels considered for these experiments were natural gas (NG) for the ashless case, pure coal, pure FB, and blends of coal and FB. Two parameters that were used to characterize the ash "fouling" were (1) the overall heat-transfer coefficient (OHTC) when burning NG and solid fuels as reburn fuels, and (2) the combustible loss through ash deposited on the surfaces of heat exchanger tubes and the bottom ash in the ash port. A new methodology is presented for determining ash-fouling behavior under transient conditions. Results on the OHTCs for solid reburn fuels are compared with the OHTCs for NG. It was found that the growth of the layer of ash depositions over longer periods typically lowers OHTC, and the increased concentration of ash in gas phase promotes radiation in high-temperature zones during initial periods while decreasing the heat transfer in low-temperature zones. The ash analyses indicated that the bottom ash in the ash port contained a smaller percentage of combustibles with a higher FB percentage in the fuels, indicating better performance compared with coal because small particles in FB burn faster and the FB has higher volatile matter on a dry ash-free basis promoting more burn out.

  16. Numerical and experimental investigation of the effect of geometry on combustion characteristics of solid-fuel ramjet

    Science.gov (United States)

    Gong, Lunkun; Chen, Xiong; Musa, Omer; Yang, Haitao; Zhou, Changsheng

    2017-12-01

    Numerical and experimental investigation on the solid-fuel ramjet was carried out to study the effect of geometry on combustion characteristics. The two-dimensional axisymmetric program developed in the present study adopted finite rate chemistry and second-order moment turbulence-chemistry models, together with k-ω shear stress transport (SST) turbulence model. Experimental data were obtained by burning cylindrical polyethylene using a connected pipe facility. The simulation results show that a fuel-rich zone near the solid fuel surface and an air-rich zone in the core exist in the chamber, and the chemical reactions occur mainly in the interface of this two regions; The physical reasons for the effect of geometry on regression rate is the variation of turbulent viscosity due to the geometry change. Port-to-inlet diameter ratio is the main parameter influencing the turbulent viscosity, and a linear relationship between port-to-inlet diameter and regression rate were obtained. The air mass flow rate and air-fuel ratio are the main influencing factors on ramjet performances. Based on the simulation results, the correlations between geometry and air-fuel ratio were obtained, and the effect of geometry on ramjet performances was analyzed according to the correlation. Three-dimensional regression rate contour obtained experimentally indicates that the regression rate which shows axisymmetric distribution due to the symmetry structure increases sharply, followed by slow decrease in axial direction. The radiation heat transfer in recirculation zone cannot be ignored. Compared with the experimental results, the deviations of calculated average regression rate and characteristic velocity are about 5%. Concerning the effect of geometry on air-fuel ratio, the deviations between experimental and theoretical results are less than 10%.

  17. Experimental investigation on NOx and green house gas emissions from a marine auxiliary diesel engine using ultralow sulfur light fuel.

    Science.gov (United States)

    Geng, Peng; Tan, Qinming; Zhang, Chunhui; Wei, Lijiang; He, Xianzhong; Cao, Erming; Jiang, Kai

    2016-12-01

    In recent years, marine auxiliary diesel engine has been widely used to produce electricity in the large ocean-going ship. One of the main technical challenges for ocean-going ship is to reduce pollutant emissions from marine auxiliary diesel engine and to meet the criteria of disposal on ships pollutants of IMO (International Maritime Organization). Different technical changes have been introduced in marine auxiliary diesel engine to apply clean fuels to reduce pollutant emissions. The ultralow sulfur light fuel will be applied in diesel engine for emission reductions in China. This study is aimed to investigate the impact of fuel (ultralow sulfur light fuel) on the combustion characteristic, NOx and green house gas emissions in a marine auxiliary diesel engine, under the 50%-90% engine speeds and the 25%-100% engine torques. The experimental results show that, in the marine auxiliary diesel engine, the cylinder pressure and peak heat release rate increase slightly with the increase of engine torques, while the ignition advances and combustion duration become longer. With the increases of the engine speed and torque, the fuel consumption decreases significantly, while the temperature of the exhaust manifold increases. The NOx emissions increase significantly with the increases of the engine speed and torque. The NO emission increases with the increases of the engine speed and torque, while the NO2 emission decreases. Meanwhile, the ratio of NO2 and NO is about 1:1 when the diesel engine operated in the low speed and load, while the ratio increases significantly with the increases of engine speed and torque, due to the increase of the cylinder temperature in the diffusive combustion mode. Moreover, the CO2 emission increases with the increases of engine speed and torque by the use of ultralow sulfur light fuel. Copyright © 2016. Published by Elsevier B.V.

  18. INVESTIGATION OF FOSSIL FUEL AND LIQUID BIOFUEL BLEND PROPERTIES USING ARTIFICIAL NEURAL NETWORK

    Directory of Open Access Journals (Sweden)

    G. Najafi

    2012-06-01

    Full Text Available Gasoline fuel is the baseline fuel in this research, to which bioethanol, biodiesel and diesel are additives. The fuel blends were prepared based on different volumes and following which, ASTM (American Society for Testing and Materials test methods analysed some of the important properties of the blends, such as: density, dynamic viscosity, kinematic viscosity and water and sediment. Experimental data were analysed by means of Matlab software. The results obtained from artificial neural network analysis of the data showed that the network with feed forward back propagation of the Levenberg-Marquardt train LM function with 10 neurons in the hidden layer was the best for predicting the parameters, including: Water and sediment (W, dynamic viscosity (DV, kinematic viscosity (KV and density (De. The experimental data had a good correlation with ANN-predicted values according to 0.96448 for regression.

  19. Thermodynamic Investigation of an Integrated Gasification Plant with Solid Oxide Fuel Cell and Steam Cycles

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2012-01-01

    A gasification plant is integrated on the top of a solid oxide fuel cell (SOFC) cycle, while a steam turbine (ST) cycle is used as a bottoming cycle for the SOFC plant. The gasification plant was fueled by woodchips to produce biogas and the SOFC stacks were fired with biogas. The produced gas...... integration configurations are completely novel and have not been studied elsewhere. Plant efficiencies of 56% were achieved under normal operation which was considerably higher than the IGCC (Integrated Gasification Combined Cycle) in which a gasification plant is integrated with a gas turbine and a steam...

  20. The Investigation of Primary School Teachers' Opinions Related to the Current Events

    Directory of Open Access Journals (Sweden)

    Halil İbrahim Sağlam

    2016-09-01

    Full Text Available The aim of this study is to examine primary school teachers’ opinions related to current events. The study group is consisted of total 30 primary school teachers who take part in THE GROUPS OF 15 female (%50 and 15 male (%50 in Sakarya during 2015 -2016 the education year. The study is carried out under science facts pattern of qualitative research designs. In order to reveal teachers’ views on current events, the form of semi-structured interviews from which is qualitative data collection tools is used. There are two sections in this study. First section is about teachers' personal information and second section is about teachers' questions to determine their views on current events. For the content validity of the questions in the negotiation form, it has been consulted with three experts and made the necessary adjustments in line with their proposals. In addition, the clarity of the questions in the negotiation form has been checked by discussing with five teachers and then the form has been finalized. The data obtained from teachers ARE analyzed by using content analysis. In the study, it is concluded that 97% of the teachers follow the current events. It is shown that 93% of female teachers and 100% male teachers follow the current events. FURTHERMORE, it is indicated that %100 of the teachers use the internet in their house.

  1. Experimental investigation of regulated and unregulated emissions from a diesel engine fueled with Euro V diesel fuel and fumigation methanol

    Science.gov (United States)

    Zhang, Z. H.; Cheung, C. S.; Chan, T. L.; Yao, C. D.

    2010-03-01

    Experiments were conducted on a four-cylinder direct-injection diesel engine with part of the engine load taken up by fumigation methanol injected into the air intake of each cylinder to investigate the regulated and unregulated gaseous emissions and particulate emission of the engine under five engine loads at an engine speed of 1920 rev min -1. The fumigation methanol was injected to top up 10%, 20% and 30% of the engine load under different engine operating conditions. The experimental results show that at low engine loads, the brake thermal efficiency (BTE) decreases with increase in fumigation methanol; but at high engine loads, the BTE is not significantly affected by fumigation methanol. The fumigation methanol results in significant increase in hydrocarbon (HC), carbon monoxide (CO) and nitrogen dioxide (NO 2) emissions, but decrease in nitrogen oxides (NO x). For the unregulated gaseous emissions, unburned methanol, formaldehyde and BTX (benzene, toluene and xylene) emissions increase but ethyne, ethene and 1,3-butadiene emissions decrease. Particulate mass and number concentrations also decrease with increase in fumigation methanol. A diesel oxidation catalyst (DOC) is found to reduce significantly most of the pollutants, including the air toxics, when the exhaust gas temperature is sufficiently high.

  2. Investigating the engine vibration in MF285 tractor effected by different blends of biodiesel fuel using statistical methods and ANFIS

    Directory of Open Access Journals (Sweden)

    A Safrangian

    2017-05-01

    Full Text Available Introduction Vibrations include a wide range of engineering sciences and discuss from different aspects. One of the aspects is related to various types of engines vibrations, which are often used as power sources in agriculture. The created vibrations can cause lack of comfort and reduce effective work and have bad influence on the health and safety. One of the important parameters of the diesel engine that has the ability to create vibration and knocking is the type of fuel. In this study, the effects of different blends of biodiesel, bioethanol and diesel on the engine vibration were investigated. As a result, a blend of fuels such as synthetic fuel that creates less vibration engine can be identified and introduced. Materials and Methods In this study, canola oil and methanol alcohol with purity of 99.99% and the molar ratio of 6:1 and sodium hydroxide catalyst with 1% by weight of oil were used for biodiesel production. Reactor configurations include: maintaining the temperature at 50 ° C, the reaction time of 5 minutes and the intensity of mixing (8000 rpm, and pump flow, 0.83 liters per minute. A Massey Ferguson (MF 285 tractor with single differential (2WD, built in 2012 at Tractor factory of Iran was used for the experiment. To measure the engine vibration signals, an oscillator with model of VM120 British MONITRAN was used. Vibration signals were measured at three levels of engine speed (2000, 1600, 1000 rpm in three directions (X, Y, Z. The analysis performed by two methods in this study: statistical data analysis and data analysis using Adaptive neuro-fuzzy inference system (ANFIS. Statistical analysis of data: a factorial experiment of 10×3 based on completely randomized design with three replications was used in each direction of X, Y and Z that conducted separately. Data were compiled and analyzed by SPSS 19 software. Ten levels of fuel were including of biodiesel (5, 15 and 25% and bioethanol (2, 4 and 6%, and diesel fuel. Data

  3. Experimental and statistical investigation of thermally induced failure in reactor fuel particles

    Energy Technology Data Exchange (ETDEWEB)

    Lunsford, J.L.; Imprescia, R.J.; Bowman, A.L.; Radosevich, C.E.

    1980-10-01

    An incomplete experimental study into the failure statistics of fuel particle for the high-temperature gas-cooled reactor (HTGR) is described. Fuel particles failure was induced by thermal ramping from room temperature to temperatures in the vicinity of 2273/sup 0/K to 2773/sup 0/K in 2 to 30 h and detected by the appearance of /sup 85/Kr in the helium carrier gas used to sweep the furnace. The concentration of krypton, a beta emitter, was detected by measuring the current that resulted when the helium sweep gas was passed through an ionization chamber. TRISO fuel particles gave a krypton concentration profile as a function of time that built up in several minutes and decayed in a fraction of an hour. This profile, which was temperature independent, was similar to the impulse response of the ionization chamber, suggesting that the TRISO particles failed instantaneously and completely. BISO fuel particles gave a krypton concentration profile as a function of time that built up in a fraction of an hour and decayed in a fraction of a day. This profile was strongly temperature dependent, suggesting that krypton release was diffusion controlled, i.e., that the krypton was diffusing through a sound coat, or that the BISO coating failed but that the krypton was unable to escape the kernel without diffusion, or that a combination of pre- and postfailure diffusion accompanied partial or complete failure.

  4. Investigation of Battery/Ultracapacitor Energy Storage Rating for a Fuel Cell Hybrid Electric Vehicle

    DEFF Research Database (Denmark)

    Schaltz, Erik; Khaligh, A.; Rasmussen, Peter Omand

    2008-01-01

    Combining high energy density batteries and high power density ultracapacitors in Fuel Cell Hybrid Electric Vehicles (FCHEV) results in a high efficient, high performance, low size, and light system. Often the batteries are rated with respect to their energy requirement in order to reduce...

  5. Vehicle fuel economy and vehicle miles traveled: An empirical investigation of Jevons' Paradox

    Science.gov (United States)

    Munyon, Vinola Vincent

    There has been, in recent decades, a concerted effort to promote energy efficiency as a means to reduce energy consumption, along the supply and demand sides. The general thesis is that, ceteris paribus, an increase in energy efficiency would lead to a decrease in the consumption of the good or service rendered efficient. This is in opposition to Jevons' Paradox which states that "It is wholly a confusion of ideas to suppose that the economical use of fuel is equivalent to a diminished consumption. The very contrary is the truth..." (Jevons, 1865). While many studies have applied Jevons' Paradox to various sectors to estimate rebound effects, few have examined if Jevons' Paradox holds when all available factors that could affect consumption of an efficient good/service are controlled for. This study hoped to fill that gap in literature. The study looked at vehicle fuel economy and vehicle miles travelled (VMT) and examined if, all else being equal, a vehicle that was more fuel efficient accrued greater VMT. Using data from the National Household Travel Survey (NHTS, 2009), a multivariate regression model was built (N = 82,485) controlling for driver, household and vehicle attributes. The findings indicated that, at the microlevel, Jevons' Paradox does hold true; a 1% increase in fuel efficiency was associated with a 1.2% increase in VMT.

  6. Numerical investigations on two-phase flow in polymer electrolyte fuel cells

    NARCIS (Netherlands)

    Qin, C.Z.

    2012-01-01

    Numerical modeling plays an important role in understanding various transport processes in polymer electrolyte fuel cells (PEFCs). It can not only provide insights into the development of new PEFC architectures, but also optimize operating conditions for better cell performance. Water balance is

  7. Experimental investigation on fuel properties of biodiesel prepared from cottonseed oil

    Science.gov (United States)

    Payl, Ashish Naha; Mashud, Mohammad

    2017-06-01

    In recent time's world's energy demands are satisfied by coal, natural gas as well as petroleum though the prices of these are escalating. If this continues, global recession is unavoidable and diminution of world reserve accelerates undoubtedly. Recently, Biodiesel is found to be more sustainable, non-toxic and energy efficient alternative which is also biodegradable. The use of biofuels in compression ignition engines is now a contemplation attention in place of petrochemicals. In view of this, cottonseed oil is quite a favorable candidate as an alternative fuel. The present study covers the various aspects of biodiesels fuel prepared from cottonseed oil. In this work Biodiesel was prepared from cottonseed oil through transesterification process with methanol, using sodium hydroxide as catalyst. The fuel properties of cottonseed oil methyl esters, kinematic viscosity, flash point, density, calorific value, boiling point etc. were evaluated and discussed in the light of Conventional Diesel Fuel. The properties of biodiesel produced from cotton seed oil are quite close to that of diesel except from flash point. And so the methyl esters of cottonseed oil can be used in existing diesel engines without any modifications.

  8. An Experimental Investigation of Hypergolic Ignition Delay of Hydrogen Peroxide with Fuel Mixtures

    Science.gov (United States)

    Blevins, John A.; Gostowski, Rudy; Chianese, Silvio

    2003-01-01

    An experimental evaluation of decomposition and ignition delay of hydrogen peroxide at concentrations of 80% to 98% with combinations of hydrocarbon fuels, tertiary amines and transition metal chelates will be presented in the proposed paper. The results will be compared to hydrazine ignition delays with hydrogen peroxide and nitric acid mixtures using the same test apparatus.

  9. Investigation into the Flow Properties of Coarse Solid Fuels for Use in Industrial Feed Systems

    Directory of Open Access Journals (Sweden)

    James M. Craven

    2015-01-01

    Full Text Available Material feeding and handling systems have been cited as one of the most common causes of process downtime where thermochemical conversion processes are concerned. New and emerging fuels come in a variety of forms, and if such fuels are to be deployed widely it is imperative that material feeding and handling systems are designed appropriately. This study proposes an approach for designing material feeding and handling systems for use with coarse solid fuels. The data obtained from this study indicates particle size to be one of the key issues affecting the flowability of bulk solids further to the uniformity in particle shape. Coarse bulk solid samples were shown to flow more freely than their milled and pulverised counterparts, generating higher degrees of flowability. The results from this study were also applied to a new feed system used for feeding solid fuels to high pressure processes named the Hydraulic Lock Hopper. In this study the Hydraulic Lock Hopper demonstrated the feeding of wood pellets, torrefied spruce pellets, and ground anthracite coal grains against a pressure of 25 barg in two modes of operation. Energy savings compared to conventional lock hopper systems were recorded in the region of 80%.

  10. An investigation on the fuel savings potential of hybrid hydraulic refuse collection vehicles.

    Science.gov (United States)

    Bender, Frank A; Bosse, Thomas; Sawodny, Oliver

    2014-09-01

    Refuse trucks play an important role in the waste collection process. Due to their typical driving cycle, these vehicles are characterized by large fuel consumption, which strongly affects the overall waste disposal costs. Hybrid hydraulic refuse vehicles offer an interesting alternative to conventional diesel trucks, because they are able to recuperate, store and reuse braking energy. However, the expected fuel savings can vary strongly depending on the driving cycle and the operational mode. Therefore, in order to assess the possible fuel savings, a typical driving cycle was measured in a conventional vehicle run by the waste authority of the City of Stuttgart, and a dynamical model of the considered vehicle was built up. Based on the measured driving cycle and the vehicle model including the hybrid powertrain components, simulations for both the conventional and the hybrid vehicle were performed. Fuel consumption results that indicate savings of about 20% are presented and analyzed in order to evaluate the benefit of hybrid hydraulic vehicles used for refuse collection. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Quantitative Investigations of Biodiesel Fuel Using Infrared Spectroscopy: An Instrumental Analysis Experiment for Undergraduate Chemistry Students

    Science.gov (United States)

    Ault, Andrew P.; Pomeroy, Robert

    2012-01-01

    Biodiesel has gained attention in recent years as a renewable fuel source due to its reduced greenhouse gas and particulate emissions, and it can be produced within the United States. A laboratory experiment designed for students in an upper-division undergraduate laboratory is described to study biodiesel production and biodiesel mixing with…

  12. A process mining-based investigation of adverse events in care processes.

    Science.gov (United States)

    Caron, Filip; Vanthienen, Jan; Vanhaecht, Kris; Van Limbergen, Erik; Deweerdt, Jochen; Baesens, Bart

    2014-01-01

    This paper proposes the Clinical Pathway Analysis Method (CPAM) approach that enables the extraction of valuable organisational and medical information on past clinical pathway executions from the event logs of healthcare information systems. The method deals with the complexity of real-world clinical pathways by introducing a perspective-based segmentation of the date-stamped event log. CPAM enables the clinical pathway analyst to effectively and efficiently acquire a profound insight into the clinical pathways. By comparing the specific medical conditions of patients with the factors used for characterising the different clinical pathway variants, the medical expert can identify the best therapeutic option. Process mining-based analytics enables the acquisition of valuable insights into clinical pathways, based on the complete audit traces of previous clinical pathway instances. Additionally, the methodology is suited to assess guideline compliance and analyse adverse events. Finally, the methodology provides support for eliciting tacit knowledge and providing treatment selection assistance.

  13. Experimental and numerical investigation of flame characteristics during swirl burner operation under conventional and oxy-fuel conditions

    Directory of Open Access Journals (Sweden)

    Jovanović Rastko D.

    2017-01-01

    Full Text Available Oxy-fuel coal combustion, together with carbon capture and storage or utilization, is a set of technologies allowing to burn coal without emitting globe warming CO2. As it is expected that oxy-fuel combustion may be used for a retrofit of existing boilers, development of a novel oxy-burners is very important step. It is expected that these burners will be able to sustain stable flame in oxy-fuel conditions, but also, for start-up and emergency reasons, in conventional, air conditions. The most cost effective way of achieving dual-mode boilers is to introduce dual-mode burners. Numerical simulations allow investigation of new designs and technologies at a relatively low cost, but for the results to be trustworthy they need to be validated. This paper proposes a workflow for design, modeling, and validation of dual-mode burners by combining experimental investigation and numerical simulations. Experiments are performed with semi-industrial scale burners in 0.5 MWt test facility for flame investigation. Novel CFD model based on ANSYS FLUENT solver, with special consideration of coal combustion process, especially regarding devolatilization, ignition, gaseous and surface reactions, NOx formation, and radiation was suggested. The main model feature is its ability to simulate pulverized coal combustion under different combusting atmospheres, and thus is suitable for both air and oxy-fuel combustion simulations. Using the proposed methodology two designs of pulverized coal burners have been investigated both experimentally and numerically giving consistent results. The improved burner design proved to be a more flexible device, achieving stable ignition and combustion during both combustion regimes: conventional in air and oxy-fuel in a mixture of O2 and CO2 (representing dry recycled flue gas with high CO2 content. The proposed framework is expected to be of use for further improvement of multi-mode pulverized fuel swirl burners but can be also used

  14. Development of a mobility and fuel strategy for Germany. Preliminary investigation; Entwicklung einer Mobilitaets- und Kraftstoffstrategie fuer Deutschland. Voruntersuchung

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-08-15

    Mobility is a key element in our society and often synonymous with traffic. It is desirable to secure a clean and diversified energy supply, to design a more sustainable transport structure and to minimize the burden on people and environment. This requires an updating of the fuel strategy 2004 and its progress toward a comprehensive mobility strategy and fuel strategy. Under this aspect, the contribution under consideration presents a preliminary investigation of the development of a mobility strategy and fuel strategy in Germany. Over the past ten years, the transport sector has reduced its energy consumption only slightly. The targets for the energy reduction now are -10 % up to 2020 and -40 % up to 2050. The transport sector challenges a significant contribution to the reduction of greenhouse gas emissions. In order to advance the necessary energy political as well as climate political changes the Federal Government wants to develop a comprehensive mobility strategy and fuel strategy. For this purpose, the contribution under consideration provides nine concrete recommendations for action for this.

  15. Development of Dual Fuel Single Cylinder Natural Gas Engine an Analysis and Experimental Investigation for Performance and Emission

    OpenAIRE

    Syed Kaleemuddin; G. A.P. Rao

    2009-01-01

    The present study reports the experimental investigations carried and upgradation of 395 cc air cooled engine to dual fuel (CNG/Gasoline) application. The original 395 cc direct injection naturally aspirated, air cooled diesel engine was first converted to run on Gasoline by addition of electronic ignition system and reduction in compression ratio to suit both gasoline and CNG application. CFX software has been employed to calculate and improve the cooling capacity of engine with the use of C...

  16. NUMERICAL INVESTIGATION OF THE EFFECTS OF AIR/FUEL RATIO ON COMBUSTION IN A SPARK IGNITION ENGINE

    OpenAIRE

    DINLER, Nureddin; YUCEL, Nuri

    2016-01-01

    Combustion is one of the main research areas of internal combustion engines. To reduce the air pollution from internal combustion engines, it is required to increase combustion efficiency. In this study, effects of air/fuel ratio were investigated numerically. An axisymmetrical internal combustion engine was modeled in order to simulate in-cylinder engine flow and combustion. Two dimensional transient continuity, momentum, turbulence, energy and combustion equations were solved. k-e turbulenc...

  17. Investigation of high temperature operation of proton exchange membrane fuel cells

    Science.gov (United States)

    Adjemian, Kevork Tro

    Proton exchange membrane fuel cells (PEMFCs) have garnered much attention in the media over the past years as they can provide a clean, environmentally friendly alternative to internal combustion engines. PEMFCs also have the flexibility to operate on many different types of fuels, thereby diminishing our reliance on foreign oil. PEMFCs, however, suffer from many drawbacks which need to be overcome before mass production becomes viable. One drawback is the expense of the fuel cell system, costing several times more than existing technologies. Another problem is that if the fuel cell is running on reformed fuels, trace amounts of carbon monoxide (10 ppm) in the hydrogen gas stream will completely poison the anode electrocatalyst, killing the PEMFC. Also, as a lot of waste heat is generated, a very elaborate cooling system needs to be used, making the overall system more expensive and complex. A possible solution to both the carbon monoxide poisoning and thermal management of a PEMFC is to elevate its operating temperature above 100°C. Unfortunately, current state-of-the-art electrolytes used in PEMFCs, i.e. Nafion 115, rely on water for the conduction of protons and by elevating the temperature, water loss occurs due to evaporation resulting in inadequate PEMFC performance. This thesis delves into the modification of Nafion and similar electrolytes to permit PEMFC operation above 100°C. This was accomplished by impregnating the pores of the Nafion with hydrophilic inorganic materials-silicon oxide via sol-gel processing and various inorganic particles. By performing these modifications to the various electrolytes, several composite membranes performed exceptionally well at an operating temperature of 130°C and demonstrated carbon monoxide tolerance of up to 500 ppm. In addition, a theory on how these materials help improve the water management characteristics of Nafion was developed, laying the foundation for the development of a completely novel membrane to

  18. The Investigation of Primary School Teachers' Opinions Related to the Current Events

    OpenAIRE

    Halil İbrahim Sağlam; Rabia Eda Bozkan; Erkan Bozkan

    2016-01-01

    The aim of this study is to examine primary school teachers’ opinions related to current events. The study group is consisted of total 30 primary school teachers who take part in THE GROUPS OF 15 female (%50) and 15 male (%50) in Sakarya during 2015 -2016 the education year. The study is carried out under science facts pattern of qualitative research designs. In order to reveal teachers’ views on current events, the form of semi-structured interviews from which is qualitative data collection ...

  19. Investigation of the Semicoa 2N7616 and 2N7425 and the Microsemi 2N7480 for Single-Event Gate Rupture and Single-Event Burnout

    Science.gov (United States)

    Scheick, Leif

    2014-01-01

    Single-event-effect test results for hi-rel total-dose-hardened power MOSFETs are presented in this report. The 2N7616 and the 2N7425 from Semicoa and the 2N7480 from International Rectifier were tested to NASA test condition standards and requirements. The 2N7480 performed well and the data agree with the manufacture's data. The 2N7616 and 2N7425 were entry parts from Semicoa using a new device architecture. Unfortunately, the device performed poorly and Semicoa is withdrawing power MOSFETs from it line due to these data. Vertical metal-oxide-semiconductor field-effect transistors (MOSFETs) are the most commonly used power transistor. MOSFETs are typically employed in power supplies and high current switching applications. Due to the inherent high electric fields in the device, power MOSFETs are sensitive to heavy ion irradiation and can fail catastrophically as a result of single-event gate rupture (SEGR) or single-event burnout (SEB). Manufacturers have designed radiation-hardened power MOSFETs for space applications. See [1] through [5] for more information. The objective of this effort was to investigate the SEGR and SEB responses of two power MOSFETs recently produced. These tests will serve as a limited verification of these parts. It is acknowledged that further testing on the respective parts may be needed for some mission profiles.

  20. Investigation of engine performance and emissions of a diesel engine with a blend of marine gas oil and synthetic diesel fuel.

    Science.gov (United States)

    Nabi, Md Nurun; Hustad, Johan Einar

    2012-01-01

    This paper investigates diesel engine performance and exhaust emissions with marine gas oil (MGO) and a blend of MGO and synthetic diesel fuel. Ten per cent by volume of Fischer-Tropsch (FT), a synthetic diesel fuel, was added to MGO to investigate its influence on the diesel engine performance and emissions. The blended fuel was termed as FT10 fuel, while the neat (100 vol%) MGO was termed as MGO fuel. The experiments were conducted with a fourstroke, six-cylinder, turbocharged, direct injection, Scania DC 1102 diesel engine. It is interesting to note that all emissions including smoke (filter smoke number), total particulate matter (TPM), carbon monoxide (CO), total unburned hydrocarbon (THC), oxides of nitrogen (NOx) and engine noise were reduced with FT10 fuel compared with the MGO fuel. Diesel fine particle number and mass emissions were measured with an electrical low pressure impactor. Like other exhaust emissions, significant reductions in fine particles and mass emissions were observed with the FT10 fuel. The reduction was due to absence of sulphur and aromatic compounds in the FT fuel. In-cylinder gas pressure and engine thermal efficiency were identical for both FT10 and MGO fuels.

  1. An Investigation of the Relationship between Stressful Life Events and Psychological, Behavioral and Physiological Outcomes

    Science.gov (United States)

    1984-09-01

    life events were significantly related to ’ "decreased job satisfacion (Sarason & Johnson, 1979). An enlarged sample size, though, would be required...19 Background..................................20 Social Arrangement. . . . . . . . 21 Individual Differences ..... ...... 2 Job Demand...Organizational problems shown by research efforts to be affected by stress have included absenteeism, decreased productivity, turnover and job

  2. Note: Tangential x-ray diagnosis for investigating fast MHD events in EAST tokamak.

    Science.gov (United States)

    Li, Erzhong; Hu, Liqun; Chen, Kaiyun; Zhang, Jizong; Chen, Yiebin; Zhou, Ruijie; Gan, Kaifu; Liu, Yong

    2010-10-01

    A tangential x-ray diagnosis has been installed in the experimental advanced superconducting tokamakvacuum vessel for the study of fast magnetohydrodynamics (MHD) events. This system is based on absolute x-ray ultraviolet detectors with a collimator which is processed by laser machine. The first experimental results have proved its ability to measure the small-scale and transient MHD perturbations.

  3. Investigating extreme event loading on coastal bridges using wireless sensor technology

    Science.gov (United States)

    Gelineau, Douglas A.; Davis, Justin R.; Rice, Jennifer A.

    2017-04-01

    Coastal infrastructure, such as bridges, are susceptible to many forms of coastal hazards: particularly hurricane surge and wave loading. These two forms of loading can cause catastrophic damage to aging highway infrastructure. It is estimated that storm damage costs the United States about $50 Billion per year. In light of this, it is crucial that we understand the damaging forces placed on infrastructure during storm events so that we can develop safer and more resilient coastal structures. This paper presents the ongoing research to enable the efficient collection of extreme event loads acting on both the substructure and superstructure of low clearance, simple span, reinforced concrete bridges. Bridges of this type were commonly constructed during the 1950's and 60's and are particularly susceptible to deck unseating caused by hurricane surge and wave loading. The sensing technology used to capture this data must be ruggedized to survive in an extremely challenging environment, be designed to allow for redundancy in the event of sensors or other network components being lost in the storm, and be relatively low cost to allow for more bridges to be instrumented per storm event. The prototype system described in this paper includes wireless technology, rapid data transmission, and, for the sensors, self-contained power. While this specific application focuses on hurricane hazards, the framework can be extended to include other natural hazards.

  4. PFOS and PFOSA in Bottlenose Dolphins: An Investigation into Two Unusually High Mortality Events

    Science.gov (United States)

    Along the Atlantic coast of the United States during 1987 and 1988, bottlenose dolphins (Tursiops truncatus) suffered one of this country's largest marine mammal mass mortality events. An estimated 50% of all near-shore bottlenose died during this short period. Two years later a ...

  5. Investigating Holocene Glacial and Pluvials Events in the Sierra Nevada of California

    Science.gov (United States)

    Ashford, J.; Sickman, J. O.; Lucero, D. M.; Kirby, M.; Gray, A. B.

    2016-12-01

    Understanding interannual and decadal variation in snowfall and extreme hydrologic events in the Sierra Nevada is hampered by short instrumental record and uncertainty caused by extrapolating paleoclimate data from lower elevation systems to the alpine snow deposition zone. Longer paleo records from high elevation systems are necessary to provide a more accurate record of snow water content and extreme precipitation events over millennial timescales that can be used to test hypotheses regarding teleconnections between Pacific climate variability and water supply and flood risk in California. In October 2013 we collected sediment cores from Pear Lake, an alpine lake in Sequoia National Park. The cores were split and characterized by P-wave velocity, magnetic susceptibility and density scanning along with grain-size analysis at 1-2 cm increments. Radiocarbon dates indicate that the Pear Lake cores contain a 13.5K year record of lake sediment. In contrast to other Sierra Nevada lakes previously cored by our group, high-resolution scanning revealed alternating fine grained, light-dark bands (1 mm to 5 mm thick) for most of the Pear Lake core length. This pattern was interrupted at intervals by homogenous clasts (up to 75 mm thick) ranging in grain size from sand to gravel up to 1 cm diameter. The sand to gravel sized clasts are most likely associated with extreme precipitation events. Preliminary grain-size analysis results show evidence of isolated extreme hydrologic events and sections of increased event frequency which we hypothesize are the result of atmospheric rivers intersecting the southern Sierra Nevada outside of the snow covered period.

  6. Cool? Young people investigate living in cold housing and fuel poverty. A mixed methods action research study.

    Science.gov (United States)

    O'Sullivan, Kimberley C; Howden-Chapman, Philippa; Sim, Dalice; Stanley, James; Rowan, Rebekah L; Harris Clark, Isobel K; Morrison, Lydia L A

    2017-12-01

    Living in cold housing conditions and risk of fuel poverty presents a range of physiological and psychosocial health risks. Limited research has specifically investigated the effects of fuel poverty on children and young people, and even less has been conducted with youth input into the research process. The Cool? Study used mixed methods, participatory action research carried out with youth researchers involved at all stages through questionnaire design, analysis, qualitative design, e-interviewing and dissemination of results. This article reports on results of an online survey of 656 adolescents aged 14-16 years completed at 17 schools in New Zealand. Sampling was based on selecting schools for invitation, with the probability of selection weighted proportional to school size, within strata defined by climate zone. Results from a small e-mail interview study of survey respondents who consented to follow-up are also reported. The study found that almost half of the survey respondents (47%) felt their home was sometimes cold during the winter; a further 40% felt their home was often or always cold. More than two thirds of respondents (70%) had shivered inside at least once during winter. Respondents were more likely to report key indicators of fuel poverty depending on their self-reported ethnicity, with Māori at increased risk. Living in private rental housing or state-owned housing also increased risk of fuel poverty compared to those in owner-occupied dwellings. Participants of email interviews expressed concern about the widespread problem of cold housing for youth and a desire for Government intervention. The integrated results confirm that cold housing and risk of fuel poverty are important problems for young people in New Zealand. Results contribute to the evidence-base for policy targeting of schemes such as the Government-sponsored retrofitting of insulation to households with dependent children.

  7. Investigation of Amphibian Mortality Events in Wildlife Reveals an On-Going Ranavirus Epidemic in the North of the Netherlands

    NARCIS (Netherlands)

    Rijks, Jolianne M; Saucedo, Bernardo; Spitzen-van der Sluijs, Annemarieke; Wilkie, Gavin S; van Asten, Alphons J A M; van den Broek, Jan; Boonyarittichaikij, Roschong; Stege, Marisca; van der Sterren, Fleur; Martel, An; Pasmans, Frank; Hughes, Joseph; Gröne, Andrea; van Beurden, Steven J; Kik, Marja J L

    2016-01-01

    In the four years following the first detection of ranavirus (genus Ranavirus, family Iridoviridae) infection in Dutch wildlife in 2010, amphibian mortality events were investigated nationwide to detect, characterize and map ranaviruses in amphibians over time, and to establish the affected host

  8. Experimental investigation of nitrogen based emissions from an ammonia fueled SI-engine

    DEFF Research Database (Denmark)

    Westlye, Fredrik Ree; Ivarsson, Anders; Schramm, Jesper

    2013-01-01

    cylinder 0.612 l CFR engine with a compression ratio varying from 7 to 15 using a fuel composition of 80 vol% NH3 and 20 vol% H2. Wet exhaust samples are analysed with an FT-IR. Emission measurements reveal that nitric oxide stem from other reaction paths than the dissociation of molecular nitrogen....... This causes the NO emissions to peak around 35% rather than 10% excess air, as is typical in HC fueled SI-engines. However the magnitude of NO emissions are comparable to that of measurements conducted with gasoline due to lower flame temperatures. Nitrogen dioxide levels are higher when comparing...... with gasoline, but has a relatively low share of the total NOx emissions (3-4%). Nitrous oxide is a product of NH2 reacting with NO 2 and NH reacting with NO. The magnitude is largely affected by ignition timing due to the temperature development during expansion and the amount of excess air, as increased...

  9. Experimental investigation on a turbine compressor for air supply system of a fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Masayasu [Sumitomo Heavy Industries, Ltd., Yokosuka (Japan); Tsuchiyama, Syozo [Shipbuilding Research Association, Minato-ku, Tokyo (Japan)

    1996-12-31

    This report covers part of a joint study on a PEFC propulsion system for surface ships, summarized in a presentation to this Seminar, entitled {open_quotes}Study on a Polymer Electrolyte Fuel Cell (PEFC) Propulsion System for Surface Ships{close_quotes}, and which envisages application to a 1,500 DWT cargo vessel. The aspect treated here concerns a study on the air supply system for the PEFC, with particular reference to system components.

  10. A Microfluidic Pore Network Approach to Investigate Water Transport in Fuel Cell Porous Transport Layers

    OpenAIRE

    Bazylak, A.; Berejnov, V.; Markicevic, B.; Sinton, D.; Djilali, N.

    2008-01-01

    Pore network modelling has traditionally been used to study displacement processes in idealized porous media related to geological flows, with applications ranging from groundwater hydrology to enhanced oil recovery. Very recently, pore network modelling has been applied to model the gas diffusion layer (GDL) of a polymer electrolyte membrane (PEM) fuel cell. Discrete pore network models have the potential to elucidate transport phenomena in the GDL with high computational efficiency, in cont...

  11. Numerical investigations on two-phase flow in polymer electrolyte fuel cells

    OpenAIRE

    Qin, C.Z.

    2012-01-01

    Numerical modeling plays an important role in understanding various transport processes in polymer electrolyte fuel cells (PEFCs). It can not only provide insights into the development of new PEFC architectures, but also optimize operating conditions for better cell performance. Water balance is critical to the operation of PEFCs, since the membrane needs to attain sufficient water for effective ionic conduction. On the other hand, too much water accumulating in PEFCs would result in mass tra...

  12. Fundamental Investigation of Jet Fuel Spray and Ignition Process in an Optically Accessible Piston Engine

    Science.gov (United States)

    2015-01-16

    cylinder head and piston were used for the current work. Schematic cross sections of the engine components used in the experiments are shown in...0533 Ignition Process in an Optically Accessible Piston Engine Sb. GRANT NUMBER Sc. PROGRAM ELEMENT NUMBER 611102 6. AUTHORS Sd. PROJECT NUMBER...Process in an Optically Accessible Piston Engine Report Title Effects of transient rate-of-injection (ROI) fuel sprays on jet development and

  13. Development of self-supporting MPLs for investigations of water transport in PEM fuel cells

    OpenAIRE

    Bauder, Alexander; Haußmann, Jan; Markötter, Henning; Wagner, Norbert; Manke, Ingo; Scholta, Joachim; Friedrich, K. Andreas

    2012-01-01

    The performance of a polymer electrolyte membrane (PEM) fuel cell has a strong dependence of its water management. The membrane needs humidity to have sufficient ion conductivity. But at high humidity, especially at high current densities, flooding of the electrodes can occur and consequently the available active area begins to decrease. The primary purpose of a micro porous layer (MPL) on a gas diffusion layer (GDL) is the effective wicking of liquid water from the catalyst layer into the di...

  14. Experimental investigation of optimal timing of the Diesel engine injection pump using biodiesel fuel

    OpenAIRE

    Kegl, Breda

    2012-01-01

    This paper discusses the influence of biodiesel on output characteristics of adiesel engine and optimal timing setup for its injection pump. The influence of biodiesel is studied by running experiments on an NA diesel bus engine MAN D2 2566 with a direct-injection M system. The fuel used is biodiesel produced from rapeseed. Special attention is focused on the determination of the optimal injection-pump timing with respect to engine harmful emissions, enginefuel consumption, and other engine p...

  15. Investigation of burnup credit allowance in the criticality safety evaluation of spent fuel casks

    Energy Technology Data Exchange (ETDEWEB)

    Lake, W.H. (USDOE, Washington, DC (USA)); Sanders, T.L. (Sandia National Labs., Albuquerque, NM (USA)); Parks, C.V. (Oak Ridge National Lab., TN (USA))

    1990-01-01

    This presentation discusses work in progress on criticality analysis verification for designs which take account of the burnup and age of transported fuel. The work includes verification of cross section data, correlation with experiments, proper extension of the methods into regimes not covered by experiments, establishing adequate reactivity margins, and complete documentation of the project. Recommendations for safe operational procedures are included, as well as a discussion of the economic and safety benefits of such designs.

  16. Design and experimental investigation of an oxy-fuel combustion system for magnetohydrodynamic power extraction

    Science.gov (United States)

    Hernandez, Manuel Johannes

    A general consensus in the scientific and research community is the need to restrict carbon emissions in energy systems. Therefore, extensive research efforts are underway to develop the next generation of energy systems. In the field of power generation, researchers are actively investigating novel methods to produce electricity in a cleaner, efficient form. Recently, Oxy-Combustion for magnetohydrodynamic power extraction has generated significant interest, since the idea was proposed as a method for clean power generation in coal and natural gas power plants. Oxy-combustion technologies have been proposed to provide high enthalpy, electrically conductive flows for direct conversion of electricity. Direct power extraction via magnetohydrodynamics (MHD) can occur as a consequence of the motion of "seeded" combustion products in the presence of magnetic fields. However, oxy-combustion technologies for MHD power extraction has not been demonstrated in the available literature. Furthermore, there are still fundamental unexplored questions remaining, associated with this technology, for MHD power extraction. In this present study, previous magnetohydrodynamic combustion technologies and technical issues in this field were assessed to develop a new combustion system for electrically conductive flows. The research aims were to fully understand the current-state-of-the-art of open-cycle magnetohydrodynamic technologies and present new future directions and concepts. The design criteria, methodology, and technical specifications of an advanced cooled oxy-combustion technology are presented in this dissertation. The design was based on a combined analytical, empirical, and numerical approach. Analytical one-dimensional (1D) design tools initiated design construction. Design variants were analyzed and vetted against performance criteria through the application of computational fluid dynamics modeling. CFD-generated flow fields permitted insightful visualization of the

  17. Investigation of a Tricarbide Grooved Ring Fuel Element for a Nuclear Thermal Rocket

    Science.gov (United States)

    Taylor, Brian D.; Emrich, Bill; Tucker, Dennis; Barnes, Marvin; Donders, Nicolas; Benensky, Kelsa

    2017-01-01

    Deep space exploration, especially that of Mars, is on the horizon as the next big challenge for space exploration. Nuclear propulsion, through which high thrust and efficiency can be achieved, is a promising option for decreasing the cost and logistics of such a mission. Work on nuclear thermal engines goes back to the days of the NERVA program. Currently, nuclear thermal propulsion is under development again in various forms to provide a superior propulsion system for deep space exploration. The authors have been working to develop a concept nuclear thermal engine that uses a grooved ring fuel element as an alternative to the traditional hexagonal rod design. The authors are also studying the use of carbide fuels. The concept was developed in order to increase surface area and heat transfer to the propellant. The use of carbides would also raise the temperature limitations of the reactor. It is hoped that this could lead to a higher thrust to weight nuclear thermal engine. This paper describes the modeling of neutronics, heat transfer, and fluid dynamics of this alternative nuclear fuel element geometry. Fabrication experiments of grooved rings from carbide refractory metals are also presented along with material characterization and interactions with a hot hydrogen environment.

  18. [Combustion zone investigation and modelling in fuel flexible suspension fired boilers]. Result summary and status

    Energy Technology Data Exchange (ETDEWEB)

    Lovmand Hvid, S.

    2011-12-15

    The project has been designed to obtain data from a power plant boiler with co-combustion, partly to gain greater knowledge of particle turnover in the fuel zone, partly to support the development of modeling tools. Data collection occurred at Studstrup Power Station Unit 4, where the fuel is a combination of coal and biomass. The boiler is equipped with 24 dust burners, four of which have been converted to firing with biomass. Measurements have been carried out in the flame zone with different fuels: coal alone, coal + straw and coal + wood. During the experiments velocity fields, temperature fields and gas concentration fields were measured in the firing zone. Also, particle samples from the flame zone ware collected. Several measurements are performed with well-known techniques, but in addition, the project developed new optical measurement methods based on UV spectroscopy. They allow measuring other gases than the hitherto known methods and allow you to gain insight into the dynamic variations beyond just mean fields. The collection of particle samples from the boiler was, as expected, a very challenging task under the given conditions, but was carried out with a largely satisfactory result. Analysis of the samples has initially failed to lead to an increased recognition of the speed of the conversion process, but the samples will be analyzed in more detail in other projects. (LN)

  19. Numerical investigations with WRF about atmospheric features leading to heavy precipitation and flood events over the Central Andes' complex topography

    Science.gov (United States)

    Zamuriano, Marcelo; Brönnimann, Stefan

    2017-04-01

    It's known that some extremes such as heavy rainfalls, flood events, heatwaves and droughts depend largely on the atmospheric circulation and local features. Bolivia is no exception and while the large scale dynamics over the Amazon has been largely investigated, the local features driven by the Andes Cordillera and the Altiplano is still poorly documented. New insights on the regional atmospheric dynamics preceding heavy precipitation and flood events over the complex topography of the Andes-Amazon interface are added through numerical investigations of several case events: flash flood episodes over La Paz city and the extreme 2014 flood in south-western Amazon basin. Large scale atmospheric water transport is dynamically downscaled in order to take into account the complex topography forcing and local features as modulators of these events. For this purpose, a series of high resolution numerical experiments with the WRF-ARW model is conducted using various global datasets and parameterizations. While several mechanisms have been suggested to explain the dynamics of these episodes, they have not been tested yet through numerical modelling experiments. The simulations captures realistically the local water transport and the terrain influence over atmospheric circulation, even though the precipitation intensity is in general unrealistic. Nevertheless, the results show that Dynamical Downscaling over the tropical Andes' complex terrain provides useful meteorological data for a variety of studies and contributes to a better understanding of physical processes involved in the configuration of these events.

  20. Solution combustion synthesis using Schiff-base aluminum complex without fuel and optical property investigations of alumina nanoparticles

    Science.gov (United States)

    Salehi, Mehdi; Arabsarhangi, Ehsan

    2015-05-01

    Synthesis of alumina nanomaterials via a solution combustion technique using Schiff base aluminum (III) complex at 820 and 950 °C for 4 h was performed successfully. The synthesis procedure was performed using the complex in the absence and presence of urea and glycine as fuel for comparison. The obtained data showed that the procedure without using fuel resulted in a better phase and morphology. To investigate the phase formation, powder X-ray diffraction technique was used. Also, SEM micrographs were used to investigate the morphology of the obtained materials. The optical properties of the obtained materials were studied by FTIR spectra. According to the PXRD data, it was found that with annealing at 950 °C, the phase formation of the obtained materials showed cubic crystal structure with cell parameter a = 3.14 Å for gamma phase. Also, by annealing at 820 °C using fuels for 4 h, the main phase was found to be in gamma.

  1. The effect of cosmic rays on biological systems - an investigation during GLE events

    Science.gov (United States)

    Belisheva, N. K.; Lammer, H.; Biernat, H. K.; Vashenuyk, E. V.

    2012-01-01

    In this study, first direct and circumstantial evidences of the effects of cosmic rays (CR) on biological systems are presented. A direct evidence of biological effects of CR is demonstrated in experiments with three cellular lines growing in culture during three events of Ground Level Enhancement (GLEs) in the neutron count rate detected by ground-based neutron monitor in October 1989. Various phenomena associated with DNA lesion on the cellular level demonstrate coherent dynamics of radiation effects in all cellular lines coincident with the time of arrival of high-energy solar particles to the near-Earth space and with the main peak in GLE. These results were obtained in the course of six separate experiments, with partial overlapping of the time of previous and subsequent experiments, which started and finished in the quiet period of solar activity (SA). A significant difference between the values of multinuclear cells in all cellular lines in the quiet period and during GLE events indicates that the cause of radiation effects in the cell cultures is an exposure of cells to the secondary solar CR near the Earth's surface. The circumstantial evidence was obtained by statistical analysis of cases of congenital malformations (CM) at two sites in the Murmansk region. The number of cases of all classes of CM reveals a significant correlation with the number of GLE events. The number of cases of CM with pronounced chromosomal abnormalities clearly correlates with the GLE events that occurred a year before the birth of a child. We have found a significant correlation between modulations of the water properties and daily background variations of CR intensity. We believe that the effects of CR on biological systems can be also mediated by fluctuations in water properties, considered as one of possible mechanisms controlling the effects of CRs on biological systems.

  2. Using the relational event model (REM) to investigate the temporal dynamics of animal social networks

    Science.gov (United States)

    Tranmer, Mark; Marcum, Christopher Steven; Morton, F. Blake; Croft, Darren P.; de Kort, Selvino R.

    2015-01-01

    Social dynamics are of fundamental importance in animal societies. Studies on nonhuman animal social systems often aggregate social interaction event data into a single network within a particular time frame. Analysis of the resulting network can provide a useful insight into the overall extent of interaction. However, through aggregation, information is lost about the order in which interactions occurred, and hence the sequences of actions over time. Many research hypotheses relate directly to the sequence of actions, such as the recency or rate of action, rather than to their overall volume or presence. Here, we demonstrate how the temporal structure of social interaction sequences can be quantified from disaggregated event data using the relational event model (REM). We first outline the REM, explaining why it is different from other models for longitudinal data, and how it can be used to model sequences of events unfolding in a network. We then discuss a case study on the European jackdaw, Corvus monedula, in which temporal patterns of persistence and reciprocity of action are of interest, and present and discuss the results of a REM analysis of these data. One of the strengths of a REM analysis is its ability to take into account different ways in which data are collected. Having explained how to take into account the way in which the data were collected for the jackdaw study, we briefly discuss the application of the model to other studies. We provide details of how the models may be fitted in the R statistical software environment and outline some recent extensions to the REM framework. PMID:26190856

  3. Using the relational event model (REM) to investigate the temporal dynamics of animal social networks.

    Science.gov (United States)

    Tranmer, Mark; Marcum, Christopher Steven; Morton, F Blake; Croft, Darren P; de Kort, Selvino R

    2015-03-01

    Social dynamics are of fundamental importance in animal societies. Studies on nonhuman animal social systems often aggregate social interaction event data into a single network within a particular time frame. Analysis of the resulting network can provide a useful insight into the overall extent of interaction. However, through aggregation, information is lost about the order in which interactions occurred, and hence the sequences of actions over time. Many research hypotheses relate directly to the sequence of actions, such as the recency or rate of action, rather than to their overall volume or presence. Here, we demonstrate how the temporal structure of social interaction sequences can be quantified from disaggregated event data using the relational event model (REM). We first outline the REM, explaining why it is different from other models for longitudinal data, and how it can be used to model sequences of events unfolding in a network. We then discuss a case study on the European jackdaw, Corvus monedula, in which temporal patterns of persistence and reciprocity of action are of interest, and present and discuss the results of a REM analysis of these data. One of the strengths of a REM analysis is its ability to take into account different ways in which data are collected. Having explained how to take into account the way in which the data were collected for the jackdaw study, we briefly discuss the application of the model to other studies. We provide details of how the models may be fitted in the R statistical software environment and outline some recent extensions to the REM framework.

  4. Brain Events Underlying Episodic Memory Changes in Aging: A Longitudinal Investigation of Structural and Functional Connectivity.

    Science.gov (United States)

    Fjell, Anders M; Sneve, Markus H; Storsve, Andreas B; Grydeland, Håkon; Yendiki, Anastasia; Walhovd, Kristine B

    2016-03-01

    Episodic memories are established and maintained by close interplay between hippocampus and other cortical regions, but degradation of a fronto-striatal network has been suggested to be a driving force of memory decline in aging. We wanted to directly address how changes in hippocampal-cortical versus striatal-cortical networks over time impact episodic memory with age. We followed 119 healthy participants (20-83 years) for 3.5 years with repeated tests of episodic verbal memory and magnetic resonance imaging for quantification of functional and structural connectivity and regional brain atrophy. While hippocampal-cortical functional connectivity predicted memory change in young, changes in cortico-striatal functional connectivity were related to change in recall in older adults. Within each age group, effects of functional and structural connectivity were anatomically closely aligned. Interestingly, the relationship between functional connectivity and memory was strongest in the age ranges where the rate of reduction of the relevant brain structure was lowest, implying selective impacts of the different brain events on memory. Together, these findings suggest a partly sequential and partly simultaneous model of brain events underlying cognitive changes in aging, where different functional and structural events are more or less important in various time windows, dismissing a simple uni-factorial view on neurocognitive aging. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  5. Investigation on Flame Characteristics and Burner Operability Issues of Oxy-Fuel Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Choudhuri, Ahsan [Univ. Of Texas, El Paso, TX (United States)

    2013-09-30

    Oxy-fuel combustion has been used previously in a wide range of industrial applications. Oxy- combustion is carried out by burning a hydrocarbon fuel with oxygen instead of air. Flames burning in this configuration achieve higher flame temperatures which present opportunities for significant efficiency improvements and direct capture of CO2 from the exhaust stream. In an effort to better understand and characterize the fundamental flame characteristics of oxy-fuel combustion this research presents the experimental measurements of flame stability of various oxyfuel flames. Effects of H2 concentration, fuel composition, exhaust gas recirculation ratio, firing inputs, and burner diameters on the flame stability of these fuels are discussed. Effects of exhaust gas recirculation i.e. CO2 and H2O (steam) acting as diluents on burner operability are also presented. The roles of firing input on flame stability are then analyzed. For this study it was observed that many oxy-flames did not stabilize without exhaust gas recirculation due to their higher burning velocities. In addition, the stability regime of all compositions was observed to decrease as the burner diameter increased. A flashback model is also presented, using the critical velocity gradient gF) values for CH4-O2-CO2 flames. The second part of the study focuses on the experimental measurements of the flow field characteristics of premixed CH4/21%O2/79%N2 and CH4/38%O2/72%CO2 mixtures at constant firing input of 7.5 kW, constant, equivalence ratio of 0.8, constant swirl number of 0.92 and constant Reynolds Numbers. These measurements were taken in a swirl stabilized combustor at atmospheric pressure. The flow field visualization using Particle Imaging Velocimetry (PIV) technique is implemented to make a better understanding of the turbulence characteristics of

  6. Stock market returns and clinical trial results of investigational compounds: an event study analysis of large biopharmaceutical companies.

    Science.gov (United States)

    Hwang, Thomas J

    2013-01-01

    For biopharmaceutical companies, investments in research and development are risky, and the results from clinical trials are key inflection points in the process. Few studies have explored how and to what extent the public equity market values clinical trial results. Our study dataset matched announcements of clinical trial results for investigational compounds from January 2011 to May 2013 with daily stock market returns of large United States-listed pharmaceutical and biotechnology companies. Event study methodology was used to examine the relationship between clinical research events and changes in stock returns. We identified public announcements for clinical trials of 24 investigational compounds, including 16 (67%) positive and 8 (33%) negative events. The majority of announcements were for Phase 3 clinical trials (N = 13, 54%), and for oncologic (N = 7, 29%) and neurologic (N = 6, 24%) indications. The median cumulative abnormal returns on the day of the announcement were 0.8% (95% confidence interval [CI]: -2.3, 13.4%; P = 0.02) for positive events and -2.0% (95% CI: -9.1, 0.7%; P = 0.04) for negative events, with statistically significant differences from zero. In the day immediately following the announcement, firms with positive events were associated with stock price corrections, with median cumulative abnormal returns falling to 0.4% (95% CI: -3.8, 12.3%; P = 0.33). For firms with negative announcements, the median cumulative abnormal returns were -1.7% (95% CI: -9.5, 1.0%; P = 0.03), and remained significantly negative over the two day event window. The magnitude of abnormal returns did not differ statistically by indication, by trial phase, or between biotechnology and pharmaceutical firms. The release of clinical trial results is an economically significant event and has meaningful effects on market value for large biopharmaceutical companies. Stock return underperformance due to negative events is greater in magnitude and persists longer than

  7. Stock market returns and clinical trial results of investigational compounds: an event study analysis of large biopharmaceutical companies.

    Directory of Open Access Journals (Sweden)

    Thomas J Hwang

    Full Text Available For biopharmaceutical companies, investments in research and development are risky, and the results from clinical trials are key inflection points in the process. Few studies have explored how and to what extent the public equity market values clinical trial results.Our study dataset matched announcements of clinical trial results for investigational compounds from January 2011 to May 2013 with daily stock market returns of large United States-listed pharmaceutical and biotechnology companies. Event study methodology was used to examine the relationship between clinical research events and changes in stock returns.We identified public announcements for clinical trials of 24 investigational compounds, including 16 (67% positive and 8 (33% negative events. The majority of announcements were for Phase 3 clinical trials (N = 13, 54%, and for oncologic (N = 7, 29% and neurologic (N = 6, 24% indications. The median cumulative abnormal returns on the day of the announcement were 0.8% (95% confidence interval [CI]: -2.3, 13.4%; P = 0.02 for positive events and -2.0% (95% CI: -9.1, 0.7%; P = 0.04 for negative events, with statistically significant differences from zero. In the day immediately following the announcement, firms with positive events were associated with stock price corrections, with median cumulative abnormal returns falling to 0.4% (95% CI: -3.8, 12.3%; P = 0.33. For firms with negative announcements, the median cumulative abnormal returns were -1.7% (95% CI: -9.5, 1.0%; P = 0.03, and remained significantly negative over the two day event window. The magnitude of abnormal returns did not differ statistically by indication, by trial phase, or between biotechnology and pharmaceutical firms.The release of clinical trial results is an economically significant event and has meaningful effects on market value for large biopharmaceutical companies. Stock return underperformance due to negative events is greater in magnitude and persists longer

  8. An fNIRS investigation of associative recognition in the prefrontal cortex with a rapid event-related design.

    Science.gov (United States)

    Schaeffer, James D; Yennu, Amarnath S; Gandy, Kellen C; Tian, Fenghua; Liu, Hanli; Park, Heekyeong

    2014-09-30

    Functional near-infrared spectroscopy (fNIRS) measures hemodynamic changes at the cortical level. The use of fNIRS is growing in popularity for studying cognitive neuroscience in which event-related designs are widely used with functional magnetic resonance imaging (fMRI). However, the applicability of event-related designs with fNIRS has not been fully understood. Therefore, the present study employed fNIRS with a rapid-presentation event-related design for investigating prefrontal cortical activity during complex associative recognition. Participants studied a list of word pairs and were later given an associative recognition test. Throughout the experiment, each event was presented rapidly (∼4s). Data were sorted based on accuracy of associative memory judgments and analyzed using the general linear model (GLM) with an event-related design. During retrieval, significant increases in oxygenated hemoglobin concentrations were observed in dorsolateral and ventrolateral prefrontal regions for successful associative recognition. When comparing retrieval to encoding, significant increases in oxygenated hemoglobin concentrations were also observed in dorsolateral prefrontal cortex. The current fNIRS results corroborate previous fMRI findings that have demonstrated the involvement of dorsolateral and ventrolateral prefrontal cortex in associative recognition. Therefore, the present study validates versatile use of fNIRS with a rapid-presentation event-related design in the investigation of neural mechanisms of associative memory. The findings of this study provide evidence that fNIRS can be a viable research method for investigating complex cognitive processes commonly of interest in cognitive neuroscience. Taken together, these results demonstrate that fNIRS can be a cost-effective and accessible experimental tool for cognitive neuroscience. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Experimental investigations on a diesel engine operated with fuel blends derived from a mixture of Pakistani waste tyre oil and waste soybean oil biodiesel.

    Science.gov (United States)

    Qasim, Muhammad; Ansari, Tariq Mahmood; Hussain, Mazhar

    2017-10-18

    The waste tyre and waste cooking oils have a great potential to be used as alternative fuels for diesel engines. The aim of this study was to convert light fractions of pyrolysis oil derived from Pakistani waste vehicle tyres and waste soybean oil methyl esters into valuable fuel and to reduce waste disposal-associated environmental problems. In this study, the waste tyre pyrolysis liquid (light fraction) was collected from commercial tyre pyrolysis plant and biodiesel was prepared from waste soybean oil. The fuel blends (FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50) were prepared from a 30:70 mixture of waste tyre pyrolysis liquid and waste soybean oil methyl esters with different proportions of mineral diesel. The mixture was named as the fuel mixture of waste oils (FMWO). FT-IR analysis of the fuel mixture was carried out using ALPHA FT-IR spectrometer. Experimental investigations on a diesel engine were carried out with various FMWO blends. It was observed that the engine fuel consumption was marginally increased and brake thermal efficiency was marginally decreased with FMWO fuel blends. FMWO10 has shown lowest NOx emissions among all the fuel blends tested. In addition, HC, CO and smoke emissions were noticeably decreased by 3.1-15.6%, 16.5-33.2%, and 1.8-4.5%, respectively, in comparison to diesel fuel, thereby qualifying the blends to be used as alternative fuel for diesel engines.

  10. Experimental study on the 300W class planar type solid oxide fuel cell stack: Investigation for appropriate fuel provision control and the transient capability of the cell performance

    Science.gov (United States)

    Komatsu, Y.; Brus, G.; Kimijima, S.; Szmyd, J. S.

    2012-11-01

    The present paper reports the experimental study on the dynamic behavior of a solid oxide fuel cell (SOFC). The cell stack consists of planar type cells with standard power output 300W. A Major subject of the present study is characterization of the transient response to the electric current change, assuming load-following operation. The present studies particularly focus on fuel provision control to the load change. Optimized fuel provision improves power generation efficiency. However, the capability of SOFC must be restricted by a few operative parameters. Fuel utilization factor, which is defined as the ratio of the consumed fuel to the supplied fuel is adopted for a reference in the control scheme. The fuel flow rate was regulated to keep the fuel utilization at 50%, 60% and 70% during the current ramping. Lower voltage was observed with the higher fuel utilization, but achieved efficiency was higher. The appropriate mass flow control is required not to violate the voltage transient behavior. Appropriate fuel flow manipulation can contribute to moderate the overshoot on the voltage that may appear to the current change. The overshoot on the voltage response resulted from the gradual temperature behavior in the SOFC stack module.

  11. Cultural Resource Investigations for the Resumption of Transient Testing of Nuclear Fuels and Material at the Idaho National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Pace, Brenda R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Williams, Julie B. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2013-11-01

    The U. S. Department of Energy (DOE) has a need to test nuclear fuels under conditions that subject them to short bursts of intense, high-power radiation called ‘transient testing’ in order to gain important information necessary for licensing new nuclear fuels for use in U.S. nuclear power plants, for developing information to help improve current nuclear power plant performance and sustainability, for improving the affordability of new generation reactors, for developing recyclable nuclear fuels, and for developing fuels that inhibit any repurposing into nuclear weapons. To meet this mission need, DOE is considering alternatives for re-use and modification of existing nuclear reactor facilities to support a renewed transient testing program. One alternative under consideration involves restarting the Transient Reactor Test (TREAT) reactor located at the Materials and Fuels Complex (MFC) on the Idaho National Laboratory (INL) site in southeastern Idaho. This report summarizes cultural resource investigations conducted by the INL Cultural Resource Management Office in 2013 to support environmental review of activities associated with restarting the TREAT reactor at the INL. These investigations were completed in order to identify and assess the significance of cultural resources within areas of potential effect associated with the proposed action and determine if the TREAT alternative would affect significant cultural resources or historic properties that are eligible for nomination to the National Register of Historic Places. No archaeological resources were identified in the direct area of potential effects for the project, but four of the buildings proposed for modifications are evaluated as historic properties, potentially eligible for nomination to the National Register of Historic Places. This includes the TREAT reactor (building #), control building (building #), guardhouse (building #), and warehouse (building #). The proposed re-use of these historic

  12. Investigation of Diesel Fuel Fire Vulnerability Parameters in Armored Personnel Carriers due to Ballistic Penetration

    Science.gov (United States)

    1985-03-22

    VIEW. (SPEC27.A) 10 The fuel was either cooled with an immersion coil refrigeration unit or heated with an electric immersion heater . The air...false floor plate was easily put out. by a fire extinguisher as in Test No. 1 or was suffocated due to the door closure as in Test Nos. 2 and 3. A...extinguished with dry powder-type fire extinguish- ers, but were easily suffocated by closing the rear- door. The reduction in the bulk temperature of the

  13. Investigation of the self-heating and spontaneous ignition of refuse-derived fuel (RDF) during storage.

    Science.gov (United States)

    Yasuhara, Akio; Amano, Yuko; Shibamoto, Takayuki

    2010-07-01

    Refuse-derived fuel (RDF)-RDF-5 according to ASTM guidelines-derived from municipal solid waste and other waste materials, has been prepared as a fuel source for power plants in Japan. RDF has been known as a stable and safe solid-fuel. However, some spontaneous ignition incidents occurred during storage of RDF in certain facilities. In the present study, the storage conditions, which might induce the spontaneous ignition in RDF samples, was investigated to understand and prevent this phenomenon. When the initial temperature of RDF sample was consistent, higher water content and shorter induction times was observed (e.g., the induction times of select RDF samples with 5.8% and 16.7% water content, was 446 and 270 min, respectively). Also, the induction time was affected by the size of a RDF sample. No relationship between bacterial fermentation and spontaneous ignition was observed. The linear relationship between the induction time and the inverse of the initial temperature of the RDF sample was obtained in the Arrhenius equation. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  14. Preparation and investigation of cheap polymer electrolyte membranes for fuel cells

    DEFF Research Database (Denmark)

    Larsen, Mikkel Juul; Ma, Yue; Lund, Peter Brilner

    The electrolyte of choice for low temperature polymer electrolyte fuel cells (PEFCs) has tra­di­ti­o­nal­ly been DuPontTM Nafion® membranes or similar poly(perfluorosulfonic acid)s. The chemical struc­ture and morphology in the hydrated state of Nafion® is shown in figure 1 from which it is seen...... that the material consists of hydrophilic and hydrophobic domains. This structure gives hy­drated Nafion® very high proton conductivity as well as great stability.[i]           However, the poly(perfluorosulfonic acid) membranes are very expensive materials, and their high water uptake, significant methanol...... crossover, and relatively poor thermal stability constitute seri­ous drawbacks with respect to their fuel cell use.[ii],[iii],[iv] These aspects propel the search for cheaper and better alternatives.           In this study membrane systems consisting of a hydrophobic poly...

  15. Investigation of ecological parameters of four-stroke SI engine, with pneumatic fuel injection system

    Science.gov (United States)

    Marek, W.; Śliwiński, K.

    2016-09-01

    The publication presents the results of tests to determine the impact of using waste fuels, alcohol, to power the engine, on the ecological parameters of the combustion engine. Alternatively fuelled with a mixture of iso- and n-butanol, indicated with "X" and "END, and gasoline and a mixture of fuel and alcohol. The object of the study was a four-stroke engine with spark ignition designed to work with a generator. Motor power was held by the modified system of pneumatic injection using hot exhaust gases developed by Prof. Stanislaw Jarnuszkiewicz, controlled by modern mechatronic systems. Tests were conducted at a constant speed for the intended use of the engine. The subject of the research was to determine the control parameters such as ignition timing, mixture composition and the degree of exhaust gas recirculation on the ecological parameters of the engine. Tests were carried out using partially quality power control. In summary we present the findings of this phase of the study.

  16. Investigation of coal fueled chemical looping combustion using Fe3O4 as oxygen carrier: Influence of variables

    Science.gov (United States)

    Sun, Xiaoyan; Xiang, Wenguo; Wang, Sha; Tian, Wendong; Xu, Xiang; Xu, Yanji; Xiao, Yunhan

    2010-06-01

    Chemical-looping combustion (CLC) is a novel combustion technique with inherent CO2 separation. Magnetite (Fe3O4) was selected as the oxygen carrier. Shenhua coal (Inner Mongolia, China), straw coke and natural coke were used as fuels for this study. Influences of operation temperatures, coal to Fe3O4 mass ratios, and different kinds of fuels on the reduction characteristics of the oxygen carrier were investigated using an atmosphere thermogravimetric analyzer (TGA). Scanning electron microscopy (SEM) was used to analyse the characteristic of the solid residues. Experimental results shown that the reaction between the coal and the oxygen carrier become strong at a temperature of higher than 800°C. As the operation temperature rises, the reduction conversion rate increases. At the temperatures of 850°C, 900°C, and 950°C, the reduction conversion rates were 37.1%, 46.5%, and 54.1% respectively. However, SEM images show that at the temperature of higher than 950°C, the iron oxides become melted and sintered. The possible operation temperature should be kept around 900°C. When the mass ratios of coal to Fe3O4 were 5/95, 10/90, 15/85, and 20/80, the reduction conversion rates were 29.5%, 40.8%, 46.5%, and 46.6% respectively. With the increase of coal, the conversion rate goes up. But there exist an optimal ratio around 15/85. Comparisons based on different kinds of fuels show that the solid fuel with a higher volatile and a more developed pore structure is conducive to the reduction reactivity of the oxygen carrier.

  17. Investigation of drop coalescence via transient shape evolution: A sequential event based approach

    CERN Document Server

    Haldar, Krishnayan; Behera, Manas Ranjan; Chakraborty, Sudipto

    2015-01-01

    While a drop of liquid is placed on another liquid surface, two possible coalescence outcomes are observed. The parent drop bounces several times, floats and then disappears within the liquid pool without producing daughter droplets. This is called complete coalescence. Another outcome is the generation of secondary droplets from the primary drop itself. This is called partial coalescence. Repetitions of such phenomenon as a successive self-similar event is also known as coalescence cascade. In a nutshell, complete coalescence is governed strongly by swallowing mechanism whereas partial coalescence is attributed to slippage mechanism and solutal Marangoni flow. Here we use high speed camera and witness that water drop coalesces completely after impacting on pool of liquid whereas drop of non-ionic surfactant (TWEEN 20) coalesces partially. We also observe that number of daughter droplet generation is a strong function of surfactant concentration. Here we utilise the images to elaborately explain both the phen...

  18. Using discrepant events in science demonstrations to promote student engagement in scientific investigations: An action research study

    Science.gov (United States)

    Mancuso, Vincent J.

    Students' scientific investigations have been identified in national standards and related reform documents as a critical component of students' learning experiences in school, yet it is not easy to implement them in science classrooms. Could science demonstrations help science teachers put this recommendation into practice? While demonstrations are a common practice in the science classroom and research has documented some positive effects in terms of student motivation and engagement from their use, the literature also shows that, as traditionally presented, science demonstrations do not always achieve their intended outcomes. This, in turn, suggested the value of investigating what design elements of demonstrations could be used to promote specific instructional goals. Employing action research as a methodology, the proposed study was developed to explore how science demonstrations can be designed so as to most effectively promote student engagement in scientific investigations. More specifically, I was interested in examining the effects of using a discrepant event as part of the demonstration, as a way to create cognitive conflict and, thus, increase interest and engagement. I also investigated the relative merit of the well-researched POE (Predict, Observe, Explain) design versus employing demonstrations that appear to the student to be unplanned (what I will refer to as NOE, or a Naturally Occurring Experience). This study was informed by Constructivism, Situated Cognition and Conceptual Change as theoretical frameworks. The project included the design, implementation and study of an intervention consisting of three instructional units designed to support students' learning of the concepts of density, molecular arrangement of gas particles, and cohesion, respectively. In each of these units, lasting a total of two 80-minute class periods, students were asked to design and conduct an investigation to gain a better understanding of the concept under study. In

  19. Syntactic comprehension in Parkinson's disease: Investigating early automatic and late integrational processes using event-related brain potentials

    OpenAIRE

    Friederici, A; Kotz, S; Werheid, K.; Hein, G; Von Cramon, D

    2003-01-01

    Parkinson's disease (PD) has been associated with a general impairment of procedures and with an impairment of syntactic procedures in particular. The present study investigated comprehension processes in PD using event-related brain potentials (ERPs). PD patients and controls listened to sentences that were either correct or syntactically or semantically incorrect. The language-related ERP component correlated with semantic processes (N400) was present in both groups. In the syntactic domain...

  20. Investigation of bacterial effects of Asian dust events through comparison with seasonal variability in outdoor airborne bacterial community

    OpenAIRE

    Jonguk Park; Tomoaki Ichijo; Masao Nasu; Nobuyasu Yamaguchi

    2016-01-01

    Atmospheric bacterial dispersion with aeolian dust has been reported to have a potential impact on public health and ecosystems. Asian dust is a major aeolian event that results in an estimated 4 million tons of Asian dust particles falling in Japan annually, 3,000?5,000 km away from their source regions. However, most studies have only investigated the effects of Asian dust during dust seasons. Therefore, in this study, outdoor bacterial abundance and community composition were determined by...

  1. Measuring workplace trauma response in Australian paramedics: an investigation into the psychometric properties of the Impact of Event Scale

    Directory of Open Access Journals (Sweden)

    Hogan N

    2015-12-01

    Full Text Available Nicola Hogan,1 Shane Costello,1 Malcolm Boyle,2 Brett Williams2 1Faculty of Education, Monash University, Clayton, VIC, Australia; 2Department of Community Emergency Health and Paramedic Practice, Monash University, Frankston, VIC, Australia Introduction: Investigation into the psychological effects of violence toward health care workers and its associated trauma is increasing. The Impact of Event Scale (IES provides a measure of current, subjective, emotional distress symptomatic of a specific traumatic event. However, its validity among paramedics is largely unknown. Problem: The purpose of this study was to investigate the psychometric properties and factor structure of the IES with a sample of Australian paramedics. Methods: The study aimed to investigate the psychometric properties and factor structure of the 15-item IES with a sample of Australian paramedics using Exploratory Factor Analysis with model fit statistics as found in confirmatory analysis. Results: Maximum Likelihood Factor Analysis with Varimax rotation supported the hypothesis that a two-factor solution would provide the best fit of the data. Procrustes rotation provided further support for this hypothesis indicating that the factors, labeled “Intrusion” and “Avoidance”, as well as the individual items of the 12-item final model, were a good fit to an ideal solution. Conclusion: The revision of the scale has improved its validity for use in the general population of paramedics, improving the potential for its use in trauma-related research. Keywords: impact of event scale, psychometrics, paramedics, occupational violence, PTSD

  2. An investigation into the effect of anode purging on the fuel cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Mokmeli, Ali; Asghari, Saeed [Isfahan Engineering Research Center, 7th kilometer of Imam Khomeini St., Isfahan (Iran)

    2010-09-15

    The anode purge is a crucial process for the fuel cell long time operation because when the hydrogen is supplied in a circulation mode, any impurities present in hydrogen will gradually accumulate which lead to output voltage loss. A mathematical model is proposed for the purge process based on some operational purge parameters. The governing equations are solved and the effect of purge process on the stack working parameters is analyzed. Purge operational parameters are determined in such a way that the minimum pressure fluctuations in the anode compartment and a compromise between the minimum voltage loss and minimum hydrogen waste are achieved. A semi-stable condition is introduced and indicated that the behavior of voltage loss and hydrogen waste at this condition with respect to purge stop time (duration which the purge valve is closed) is semi-logarithmic. (author)

  3. Preliminary investigation of single chamber single electrode microbial fuel cell using sewage sludge as a substrate

    Science.gov (United States)

    Sai Chaithanya, M.; Thakur, Somil; Sonu, Kumar; Das, Bhaskar

    2017-11-01

    A microbial fuel cell (MFC) consists of a cathode and anode; micro-organisms transfer electrons acquired from the degradation of organic matter in the substrate to anode; and thereby to cathode; by using an external circuit to generate electricity. In the present study, a single chamber single electrode microbial fuel cell has been fabricated to generate electricity from the sludge of the sewage treatment plant at two different ambient temperature range of 25 ± 4°C and 32 ± 4°C under aerobic condition. No work has been done yet by using the single electrode in any MFC system; it is hypothesized that single electrode submerged partially in substrate and rest to atmosphere can function as both cathode and anode. The maximum voltage obtained was about 2890 mV after 80 (hrs) at temperature range of 25 ± 4°C, with surface power density of 1108.29 mW/m2. When the ambient temperature was 32 ± 4°C, maximum voltage obtained was 1652 mV after 40 (hrs.) surface power density reduced to 865.57 mW/m2. When amount of substrate was decreased for certain area of electrode at 25 ± 4°C range, electricity generation decreased and it also shortened the time to reach peak voltage. On the other hand, when the ambient temperature was increased to 32 ± 4°C, the maximum potential energy generated was less than that of previous experiment at 25 ± 4°C for the same substrate Also the time to reach peak voltage decreased to 40 hrs. When comparing with other single chamber single electrode MFC, the present model is generating more electricity that any MFC using sewage sludge as substrate except platinum electrode, which is much costlier that electrode used in the present study.

  4. Final Report: Investigation of Catalytic Pathways for Lignin Breakdown into Monomers and Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Gluckstein, Jeffrey A [ORNL; Hu, Michael Z. [ORNL; Kidder, Michelle [ORNL; McFarlane, Joanna [ORNL; Narula, Chaitanya Kumar [ORNL; Sturgeon, Matthew R [ORNL

    2010-12-01

    Lignin is a biopolymer that comprises up to 35% of woody biomass by dry weight. It is currently underutilized compared to cellulose and hemicellulose, the other two primary components of woody biomass. Lignin has an irregular structure of methoxylated aromatic groups linked by a suite of ether and alkyl bonds which makes it difficult to degrade selectively. However, the aromatic components of lignin also make it promising as a base material for the production of aromatic fuel additives and cyclic chemical feed stocks such as styrene, benzene, and cyclohexanol. Our laboratory research focused on three methods to selectively cleave and deoxygenate purified lignin under mild conditions: acidolysis, hydrogenation and electrocatalysis. (1) Acidolysis was undertaken in CH2Cl2 at room temperature. (2) Hydrogenation was carried out by dissolving lignin and a rhodium catalyst in 1:1 water:methoxyethanol under a 1 atm H2 environment. (3) Electrocatalysis of lignin involved reacting electrically generated hydrogen atoms at a catalytic palladium cathode with lignin dissolved in a solution of aqueous methanol. In all of the experiments, the lignin degradation products were identified and quantified by gas chromatography mass spectroscopy and flame ionization detection. Yields were low, but this may have reflected the difficulty in recovering the various fractions after conversion. The homogeneous hydrogenation of lignin showed fragmentation into monomers, while the electrocatalytic hydrogenation showed production of polyaromatic hydrocarbons and substituted benzenes. In addition to the experiments, promising pathways for the conversion of lignin were assessed. Three conversion methods were compared based on their material and energy inputs and proposed improvements using better catalyst and process technology. A variety of areas were noted as needing further experimental and theoretical effort to increase the feasibility of lignin conversion to fuels.

  5. Investigating event-specific drought attribution using self-organizing maps

    Science.gov (United States)

    Harrington, L. J.; Gibson, P. B.; Dean, S. M.; Mitchell, D.; Rosier, S.; Frame, D. J.

    2016-12-01

    Previous studies evaluating anthropogenic influences on the meteorological drivers of drought have found mixed results owing to (1) the complex physical mechanisms which lead to the onset of drought, (2) differences in the characteristics and timescales of drought for different regions of the world, and (3) different approaches to the question of attribution. For a mid-latitude, temperate climate like New Zealand, strongly modulated by oceanic influences, summer droughts last on the order of three months, and are less strongly linked to persistent temperature anomalies than continental climates. Here, we demonstrate the utility of a novel approach for characterizing the meteorological conditions conducive to extreme drought over the North Island of New Zealand, using the January-March 2013 event as a case study. Specifically, we consider the use of self-organizing map (SOM) techniques in a multi-member coupled climate model ensemble to capture changes in daily circulation, between two 41-year periods (1861-1901 and 1993-2033). Comparisons are made with seasonal pressure and precipitation indices. Our results demonstrate robust (>99% confidence) increases in the likelihood of observing circulation patterns like those of the 2013 drought in the recent-climate simulations when compared with the early-climate simulations. Best-guess estimates of the fraction of attributable risk range from 0.2 to 0.4, depending on the metric used and threshold considered. Contributions to uncertainty in these attribution statements are discussed.

  6. An event-related potential investigation of the relationship between semantic and perceptual levels of representation

    NARCIS (Netherlands)

    Van Schie, H.T.; Wijers, A.A.; Kellenbach, M.L; Stowe, L.A.

    The present study was conducted to investigate relationships between semantic and perceptual levels of representation. A picture - word repetition paradigm was used in which we manipulated the semantic relationship between pictures and words. Experiment I involved two types of trials, one with words

  7. Experimental Investigation of the Stability and Fate of Ferrihydrite during Aqueous Events on Early Mars

    Science.gov (United States)

    Dehouck, E.; McLennan, S. M.; Sklute, E.; Dyar, M. D.

    2016-12-01

    Ferrihydrite is a nanocrystalline, hydrated iron oxide species. On Earth, it is found in many surface and near-surface environments, including cold and hot springs, fresh and acid sulfate waters, lacustrine and marine sediments, and various types of soils. On Mars, its presence is suggested by measurements from the Mössbauer instruments of the Mars Exploration Rovers Spirit and Opportunity, and by mass balance calculations based on results from the CheMin X-ray diffractometer aboard the Mars Science Laboratory rover Curiosity. Gusev, Meridiani and Gale landing sites all show evidence of aqueous events, but in a wide range of conditions - e.g., acidic to circum-neutral pH, fluvio-lacustrine to playa-like to hydrothermal systems. Given the metastability of ferrihydrite, it is unclear what would have been its fate in these various geological contexts. Accordingly, we will present a series of laboratory experiments aimed at a better understanding of the stability and fate of ferrihydrite during episodes of rock/water interactions on early Mars. Ferrihydrite was altered at low (40 °C) and high (150 °C) temperature, in pure form or in mixtures with silica gel or olivine, and at several pHs. Samples were analyzed by X-ray diffraction, Mössbauer spectroscopy and visible/near-infrared (VNIR) spectroscopy. Results obtained at low temperature are at odds with some earlier studies and suggest that ferrihydrite behaves quite differently in rock-dominated conditions compared to water-dominated conditions. The co-existence of amorphous silica appears to slow down the recrystallization to hematite at high temperature and to favor the conversion into jarosite over goethite under low-T, acidic conditions. We will discuss the implications of these results for the aqueous history of Mars.

  8. Using a New Event-Based Simulation Framework for Investigating Resource Provisioning in Clouds

    Directory of Open Access Journals (Sweden)

    Simon Ostermann

    2011-01-01

    Full Text Available Today, Cloud computing proposes an attractive alternative to building large-scale distributed computing environments by which resources are no longer hosted by the scientists' computational facilities, but leased from specialised data centres only when and for how long they are needed. This new class of Cloud resources raises new interesting research questions in the fields of resource management, scheduling, fault tolerance, or quality of service, requiring hundreds to thousands of experiments for finding valid solutions. To enable such research, a scalable simulation framework is typically required for early prototyping, extensive testing and validation of results before the real deployment is performed. The scope of this paper is twofold. In the first part we present GroudSim, a Grid and Cloud simulation toolkit for scientific computing based on a scalable simulation-independent discrete-event engine. GroudSim provides a comprehensive set of features for complex simulation scenarios from simple job executions on leased computing resources to file transfers, calculation of costs and background load on resources. Simulations can be parameterised and are easily extendable by probability distribution packages for failures which normally occur in complex distributed environments. Experimental results demonstrate the improved scalability of GroudSim compared to a related process-based simulation approach. In the second part, we show the use of the GroudSim simulator to analyse the problem of dynamic provisioning of Cloud resources to scientific workflows that do not benefit from sufficient Grid resources as required by their computational demands. We propose and study four strategies for provisioning and releasing Cloud resources that take into account the general leasing model encountered in today's commercial Cloud environments based on resource bulks, fuzzy descriptions and hourly payment intervals. We study the impact of our techniques to the

  9. Using an Emergency Department Syndromic Surveillance System to investigate the impact of extreme cold weather events.

    Science.gov (United States)

    Hughes, H E; Morbey, R; Hughes, T C; Locker, T E; Shannon, T; Carmichael, C; Murray, V; Ibbotson, S; Catchpole, M; McCloskey, B; Smith, G; Elliot, A J

    2014-07-01

    This report describes the development of novel syndromic cold weather public health surveillance indicators for use in monitoring the impact of extreme cold weather on attendances at EDs, using data from the 2010-11 and 2011-12 winters. A number of new surveillance indicators were created specifically for the identification and monitoring of cold weather related ED attendances, using the diagnosis codes provided for each attendance in the Emergency Department Syndromic Surveillance System (EDSSS), the first national syndromic surveillance system of its kind in the UK. Using daily weather data for the local area, a time series analysis to test the sensitivity of each indicator to cold weather was undertaken. Diagnosis codes relating to a health outcome with a potential direct link to cold weather were identified and assigned to a number of 'cold weather surveillance indicators'. The time series analyses indicated strong correlations between low temperatures and cold indicators in nearly every case. The strongest fit with temperature was cold related fractures in females, and that of snowfall was cold related fractures in both sexes. Though currently limited to a small number of sentinel EDs, the EDSSS has the ability to give near real-time detail on the magnitude of the impact of weather events. EDSSS cold weather surveillance fits well with the aims of the Cold Weather Plan for England, providing information on those particularly vulnerable to cold related health outcomes severe enough to require emergency care. This timely information aids those responding to and managing the effects on human health, both within the EDs themselves and in the community as a whole. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  10. Experiment Investigation of the Influencing Factors on Bed Agglomeration During Fluidized-Bed Gasification of Biomass Fuels

    Science.gov (United States)

    Chen, Y. Q.; Chen, H. P.; Yang, H. P.; Wang, X. H.; Zhang, S. H.

    With the depleting of fossil fuel and environmental polluting increasing, the utilization of biomass resources caught increasing concern. Biomass gasification in fluidized bed, as one promising technology, developed quickly. However, serious agglomeration was displayed as biomass ash reacted with bed material (silica sand) at higher temperature. It hindered the wide utilization of CFB gasifier. The objective ofthis work is to investigate the agglomeration behavior between biomass ash and silica sand, and catch the inherent mechanism. Firstly, the influence of ash compounds on the agglomeration behavior was analyzed with biomass ash and synthesis ash compounds addition in fixed bed as ash sample mixed with bed material evenly before every trial. The reaction temperature was set 850°C that is the operated temperature for many fluidized bed gasificated biomass fuels. Then the influence of reaction time was analyzed. The characteristics of the agglomerated silica sand particles were analyzed by the XRD. Finally, it was simulated with HSC computer mode based on thermodynamic equilibrium. It was observed that when the ratio of the biomass ash to the silica sand was above 0.2, the agglomeration was observed. With the increase of the reaction time, more silica sand particles agglomerated with the biomass ash. There are two kinds of silicate eutecticum investigated by the XRD. It is of great significance for the running ofCFB biomass gasifier and the development ofbiomass utilization technology.

  11. Investigation of nanostructured electrocatalysts and mass transport phenomena in polymer electrolyte fuel cells

    Science.gov (United States)

    Goenaga, Gabriel A.

    Proton exchange membrane (PEM) fuel cells (FC) are promising devices in the search of clean and efficient technologies to reduce the use of fossil fuels. However, their poor performance in dynamic applications and high cost of platinum group metal (PGM) catalysts, have prevented them from becoming an affordable solution. This dissertation comprehend three research projects that study the mass transport phenomena in modified PEMs, the reduction of the amount of PGM catalyst used for oxygen reduction reaction (ORR) and the use of non-PGM catalysts as alternative catalyst to Pt for ORR. Nafion is the most used PEM for FC applications. Nafion proton conductivity is proportional to its degree of hydration, what imposes low temperature operation to maintain appropriate water content. In this research, Nafion composite membranes doped with hydrophilic metal inorganic particles have been studied using pulse field gradient (PFG) nuclear magnetic resonance (NMR). The Nafion composite membranes were found to have higher water uptake, higher water retention, higher water diffusion and, in some cases, lower methanol diffusion (crossover) than the filler free Nafion membrane. The amount of Pt and PGM catalysts supported on carbon used in the electrodes, has a great impact in the PEMFC cost. In particular, it is of high relevance to reduce the amount of Pt in the cathode electrode, in which the sluggish ORR demands four to five times more Pt catalyst than in the anode. In this thesis is shown that the use of aligned carbon nanotubes (ACNTs) as Pt support, allows a more uniform distribution of the Pt nanoparticles, what in addition to their high hydrophobicity and high corrosive resistance, lead to improved mass transport and stability of the membrane electrode assembly (MEA), when compared to a benchmark MEA that uses Pt catalyst supported on carbon black. The improvement was accomplished using less Pt than in the benchmark MEA. Replacing Pt with non-PGM catalyst can lead to an

  12. Project proposals on the creation of Russian-American joint enterprise for investigation, development and manufacture of power plants on the basis of solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Smotrov, N.V.; Kleschev, Yu.N.

    1996-04-01

    This paper describes a proposal for a joint Russian-American enterprise for performing scientific investigations, development, and manufacture of fuel cell power plants on the basis of the solid oxide fuel cell. RASOFCo. Russian-American Solid Oxide Fuel Cells Company. RASOFCo will provide the series output of the electrochemical generator (ECG) of 1kW power, then of 5kW and 10kW as well as the development and the output of 10kW power plant with the subsequent output of a power plant of greater power. An ECG based on solid oxide fuel cells uses methane as a fuel. Predicted technical characteristics, market analysis, assessment of potential demands for power plants of low power for Tyumentransgas, participants of the joint enterprise and their founding contributions, strategy for manufacture and financing, and management of RASOFCo are discussed.

  13. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL)Established to investigate, integrate, testand verifyperformance and technology readiness offuel cell systems and fuel reformers for use with...

  14. Verbal Learning and Memory in Cannabis and Alcohol Users: An Event-Related Potential Investigation

    Directory of Open Access Journals (Sweden)

    Janette L. Smith

    2017-12-01

    Full Text Available Aims: Long-term heavy use of cannabis and alcohol are known to be associated with memory impairments. In this study, we used event-related potentials to examine verbal learning and memory processing in a commonly used behavioral task.Method: We conducted two studies: first, a small pilot study of adolescent males, comprising 13 Drug-Naive Controls (DNC, 12 heavy drinkers (HD and 8 cannabis users (CU. Second, a larger study of young adults, comprising 45 DNC (20 female, 39 HD (16 female, and 20 CU (9 female. In both studies, participants completed a modified verbal learning task (the Rey Auditory Verbal Learning Test, RAVLT while brain electrical activity was recorded. ERPs were calculated for words which were subsequently remembered vs. those which were not remembered, and for presentations of learnt words, previously seen words, and new words in a subsequent recognition test. Pre-planned principal components analyses (PCA were used to quantify the ERP components in these recall and recognition phases separately for each study.Results: Memory performance overall was slightly lower than published norms using the standardized RAVLT delivery, but was generally similar and showed the expected changes over trials. Few differences in performance were observed between groups; a notable exception was markedly poorer delayed recall in HD relative to DNC (Study 2. PCA identified components expected from prior research using other memory tasks. At encoding, there were no between-group differences in the usual P2 recall effect (larger for recalled than not-recalled words. However, alcohol-related differences were observed in a larger P540 (indexing recollection in HD than DNC, and cannabis-related differences were observed in a smaller N340 (indexing familiarity and a lack of previously seen > new words effect for P540 in Study 2.Conclusions: This study is the first examination of ERPs in the RAVLT in healthy control participants, as well as substance

  15. Investigation of single event upset subject to protons of intermediate energy range

    Energy Technology Data Exchange (ETDEWEB)

    Takami, Y.; Shiraishi, F. (Rikkyo Univ., Yokosuka, Kanagawa (Japan). Inst. for Atomic Energy); Goka, T.; Shimano, Y. (Tsukuba Space Center, NASDA, 2-1-1, Sengen, Tsukuba, Ibaragi 305 (JP)); Sekiguchi, M.; Shida, K. (Inst. for Nuclear Energy, Univ. of Tokyo, 3-2-1 Midoricho, Tanashi, Tokyo 188 (JP)); Kishida, N.; Kadotani, H. (Century Research Center Corp., Tokyo (Japan)); Kikuchi, T. (NEC Corp., 4035 Ikebecho, Midoriku, Yokohama, Kanagawa 226 (JP)); Hoshino, N. (Toshiba Corp., Kawasaki (Japan)); Murakami, S. (Fujitsu Labs. Ltd., Kawasaki, Kanagawa (Japan)); Anayama, H.; Morio, A. (Reliability Center for Electonic Components of Japan, 3-4-13 Nihonbashi, Chuoku, Tokyo 103 (JP))

    1990-12-01

    Nuclear reaction models to reproduce p + Si nuclear reactions precisely in the incident proton energy region of below 50 MeV were investigated, and a computer code based on exciton models was developed. Si irradiation experiments in the intermediate energy region were performed to measure energy deposit by p + Si nuclear reactions, with two totally depleted Si detectors in face-to-face arrangement. Coincident signals were analyzed by a two dimensional pulse height analyzer. This method is shown to be effective in discriminating signals of contaminating particles.

  16. A Numerical Investigation of the Thermal Stresses of a Planar Solid Oxide Fuel Cell

    Directory of Open Access Journals (Sweden)

    Paulina Pianko-Oprych

    2016-09-01

    Full Text Available A typical operating temperature of a solid oxide fuel cell (SOFC is quite high above 750 °C and affects the thermomechanical behavior of the cell. Thermal stresses may cause microstructural instability and sub-critical cracking. Therefore, a joint analysis by the computational fluid dynamics (CFD and computational structural mechanics based on the finite element method (FEM was carried out to analyze thermal stresses in a planar SOFC and to predict potential failure locations in the cell. A full numerical model was based on the coupling of thermo-fluid model with the thermo-mechanical model. Based on a temperature distribution from the thermo-fluid model, stress distribution including the von Mises stress, shear stress as well as the operating principal stress were derived in the thermo-mechanical model. The FEM calculations were performed under different working conditions of the planar SOFC. The highest total stress was noticed at the lower operating voltage of 0.3 V, while the lowest total stress was determined at the voltage of 0.7 V. The obtained stress distributions allowed a better understanding of details of internal processes occurring within the SOFC and provided helpful guidance in the optimization of a new SOFC design.

  17. BISON Investigation of the Effect of the Fuel- Cladding Contact Irregularities on the Peak Cladding Temperature and FCCI Observed in AFC-3A Rodlet 4

    Energy Technology Data Exchange (ETDEWEB)

    Medvedev, Pavel G. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    The primary objective of this report is to document results of BISON analyses supporting Fuel Cycle Research and Development (FCRD) activities. Specifically, the present report seeks to provide explanation for the microstructural features observed during post irradiation examination of the helium-bonded annular U-10Zr fuel irradiated during the AFC-3A experiment. Post irradiation examination of the AFC-3A rodlet revealed microstructural features indicative of the fuel-cladding chemical interaction (FCCI) at the fuel-cladding interface. Presence of large voids was also observed in the same locations. BISON analyses were performed to examine stress and temperature profiles and to investigate possible correlation between the voids and FCCI. It was found that presence of the large voids lead to a formation of circumferential temperature gradients in the fuel that may have redirected migrating lanthanides to the locations where fuel and cladding are in contact. Resulting localized increase of lanthanide concentration is expected to accelerate FCCI. The results of this work provide important guidance to the post irradiation examination studies. Specifically, the hypothesis of lanthanides being redirected from the voids to the locations where the fuel and the cladding are in contact should be verified by conducting quantitative electron microscopy or Electron Probe Micro-Analyzer (EPMA). The results also highlight the need for computer models capable of simulating lanthanide diffusion in metallic fuel and establish a basis for validation of such models.

  18. Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine

    Energy Technology Data Exchange (ETDEWEB)

    Oener, Cengiz [Technical Education Faculty, Automotive Division, Firat University, 23119 Elazig (Turkey); Altun, Sehmus [Technical Education Faculty, Automotive Division, Batman University, 72060 Batman (Turkey)

    2009-10-15

    In this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NO{sub x}), sulphur dioxide (SO{sub 2}) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NO{sub x} emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification. (author)

  19. Numerical investigation of the effect of cathode catalyst layer structure and composition on polymer electrolyte membrane fuel cell performance

    Science.gov (United States)

    Kamarajugadda, Sai; Mazumder, Sandip

    The effect of the cathode catalyst layer's structure and composition on the overall performance of a polymer electrolyte membrane fuel cell (PEMFC) is investigated numerically. The starting point of the sub-grid scale catalyst layer model is the well-known flooded agglomerate concept. The proposed model addresses the effects of ionomer (Nafion) loading, catalyst (platinum) loading, platinum/carbon ratio, agglomerate size and cathode layer thickness. The sub-grid scale model is first validated against experimental data and previously published results, and then embedded within a two-dimensional validated computational fluid dynamics code that can predict the overall performance of the fuel cell. The integrated model is then used to explore a wide range of the compositional and structural parameter space, mentioned earlier. In each case, the model is able to correctly predict the trends observed by past experimental studies. It is found that the performance trends are often different at intermediate versus high current densities-the former being governed by agglomerate-scale (or local) losses, while the latter is governed by catalyst layer thickness-scale (or global) losses. The presence of an optimal performance with varying Nafion content in the cathode is more due to the local agglomerate-scale mass transport and conductivity losses in the polymer coating around the agglomerates than due to the amount of Nafion within the agglomerate. It is also found that platinum mass loading needs to be at a moderate level in order to optimize fuel cell performance, even if cost is to be disregarded.

  20. Investigation of Colour Reconnection in WW Events with the DELPHI detector at LEP-2

    CERN Document Server

    Abdallah, J; Adam, W; Adzic, P; Albrecht, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Amaldi, Ugo; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W D; Arnoud, Y; Ask, S; Åsman, B; Augustin, J E; Augustinus, A; Baillon, P; Ballestrero, A; Bambade, P; Barbier, R; Bardin, D; Barker, G J; Baroncelli, A; Battaglia, M; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Ben-Haim, E; Benekos, N; Benvenuti, A; Bérat, C; Berggren, M; Berntzon, L; Bertrand, D; Besancon41, M; Besson, N; Bloch, D; Blom, M; Bluj, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Brenner, R; Brodet, E; Brückman, P; Brunet8, J M; Buschbeck55, B; Buschmann, P; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F; Chapkin, M; Charpentier, P; Checchia, P; Chierici, R; Shlyapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Crennell, D J; Cuevas-Maestro, J; D'Hondt, J; Dalmau, J; Da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; De Paula, L; Di Ciaccio, L; Di Simone, A; Doroba, K; Drees, J; Eigen, G; Ekelöf, T J C; Ellert, M; Elsing, M; Espirito-Santo, M C; Fanourakis, G K; Fassouliotis, D; Feindt, M; Fernández, J; Ferrer, A; Ferro, F; Flagmeyer, U; Föth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J; Gandelman, M; García, C; Gavillet, P; Gazis, E; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Herr, H; Hoffman, J; Holmgren, S O; Holt, P J; Houlden, M A; Jackson, J N; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Johansson, P D; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Katsanevas, S; Katsoufis, E; Kernel, G; Kersevan, B P; Kerzel, U; King, B T; Kjaer, N J; Kluit, P; Kokkinias, P; Kourkoumelis, C; Kuznetsov, O; Krumshtein, Z; Kucharczyk, M; Lamsa, J; Leder, G; Ledroit, F; Leinonen, L; Leitner, R; Lemonne, J; Lepeltier, V; Lesiak, T; Liebig, W; Liko, D; Lipniacka, A; Lopes, J H; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; McNulty, R; Meroni, C; Migliore, E; Mitaroff, W A; Mjörnmark, U; Moa, T; Moch, R; Mönig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Müller, U; Münich, K; Mulders, M; Mundim, L; Murray, W; Muryn, B; Myatt, G; Myklebust, T; Nassiakou, M; Navarria, F; Nawrocki, K; Nicolaidou, R; Nikolenko, M; Oblakowska-Mucha, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, R; Österberg, K; Ouraou, A; Oyanguren, A; Paganoni, M; Paiano, S; Palacios, J P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Pozdnyakov, V; Pukhaeva, N; Pullia, A; Rames, J; Read, A; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P B; Richard, F; Rídky, J; Rivero, M; Rodríguez, D; Romero, A; Ronchese, P; Roudeau, P; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovskii, A; Salmi, L; Salt, J; Sander, C; Savoy-Navarro, A; Schwickerath, U; Sekulin, R; Siebel, M; Sisakian, A; Smadja, G; Smirnova, O; Sokolov, A; Sopczak, A; Sosnowski, R; Spassoff, Tz; Stanitzki, M; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli de Fatis, T; Taffard, A C; Tegenfeldt, F; Timmermans, J; Tkatchev, L; Tobin, M; Todorovova, S; Tomé, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M L; Tyapkin, I A; Tyapkin, P; Tzamarias, S; Uvarov, V; Valenti, G; van Dam, P; Van Eldik, J; Van Remortel, N; Van Vulpen, I; Vegni, G; Veloso, F; Venus, W; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weiser, C; Wicke, D; Wickens, J; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O; Zalewska-Bak, A; Zalewski, P; Zavrtanik, D; Zhuravlov, V; Zimin, N; Zintchenko, A; Zupan, M

    2007-01-01

    In the reaction e+e- -> WW -> (q_1 qbar_2)(q_3 qbar_4) the usual hadronization models treat the colour singlets q_1 qbar_2 and q_3 qbar_4 coming from two W bosons independently. However, since the final state partons may coexist in space and time, cross-talk between the two evolving hadronic systems may be possible during fragmentation through soft gluon exchange. This effect is known as Colour Reconnection. In this article the results of the investigation of Colour Reconnection effects in fully hadronic decays of W pairs in DELPHI at LEP are presented. Two complementary analyses were performed, studying the particle flow between jets and W mass estimators, with negligible correlation between them, and the results were combined and compared to models. In the framework of the SK-I model, the value for its kappa parameter most compatible with the data was found to be: kappa_{SK-I} = 2.2^{+2.5}_{-1.3} corresponding to the probability of reconnection P_{reco} to be in the range 0.31 < P_{reco} < 0.68 at 68%...

  1. Investigation of nano Pt and Pt-based alloys electrocatalysts for direct methanol fuel cells and their properties

    Directory of Open Access Journals (Sweden)

    Chunguang Suo

    2014-03-01

    Full Text Available The electrocatalysts used in micro direct methanol fuel cell (μDMFC, such as Pt/C and Pt alloy/C, prepared by liquid-phase NaBH4 reduction method have been investigated. XC-72 (Cobalt corp. Company, U.S.A is chosen as the activated carrier for the electrocatalysts to keep the catalysts powder in the range of several nanometers. The XRD, SEM, EDX analyses indicated that the catalysts had small particle size in several nanometers, in excellent dispersed phase and the molar ratio of the precious metals was found to be optimal. The performances of the DMFCs using cathodic catalyst with Pt percentage of 30wt% and different anodic catalysts (Pt-Ru, Pt-Ru-Mo were tested. The polarization curves and power density curves of the cells were measured to determine the optimal alloy composition and condition for the electrocatalysts. The results showed that the micro direct methanol fuel cell with 30wt% Pt/C as the cathodic catalyst and n(Pt:n(Ru:n(Mo = 3:2:2 PtRuMo/C as the anodic catalyst at room temperature using 2.0mol/L methanol solution has the best performances.

  2. Raman spectroscopic investigation of graphitization of diamond during spark plasma sintering of UO{sub 2}-diamond composite nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhichao [Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, 32611 (United States); Subhash, Ghatu, E-mail: subhash@ufl.edu [Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, 32611 (United States); Tulenko, James S. [Materials Science and Engineering, University of Florida, Gainesville, FL, 32611 (United States)

    2016-07-15

    Micro-Raman spectroscopy (MRS) was utilized to investigate the graphitization of diamond particles within a UO{sub 2}-diamond composite processed by spark plasma sintering (SPS). While pure diamond gives a sharp Raman peak at 1331.6 cm{sup −1}, the graphitized diamond shows broad peaks either at 1350 cm{sup −1} (G-peak) or 1580 cm{sup −1} (D-peak). The degree of graphitization was quantified by calculating the area beneath the diamond and graphite peaks. It was found that more than 20% of diamond was graphitized on the surface of the UO{sub 2}-diamond pellet and only around 10% diamond was graphitized in the interior regions of the pellet. This current study highlights the necessity to review the implications of these results carefully while implementing UO{sub 2}-diamond composite nuclear fuel. - Highlights: • Characterized the phase transformation of diamond in UO{sub 2}-diamond composite fuel. • Quantified the degree of graphitization using Raman spectroscopy. • Discussed the effect of spark plasma sintering on the graphitization.

  3. Experimental Investigation and Discussion on the Mechanical Endurance Limit of Nafion Membrane Used in Proton Exchange Membrane Fuel Cell

    Directory of Open Access Journals (Sweden)

    Yang Xiao

    2014-10-01

    Full Text Available As a solution of high efficiency and clean energy, fuel cell technologies, especially proton exchange membrane fuel cell (PEMFC, have caught extensive attention. However, after decades of development, the performances of PEMFCs are far from achieving the target from the Department of Energy (DOE. Thus, further understanding of the degradation mechanism is needed to overcome this obstacle. Due to the importance of proton exchange membrane in a PEMFC, the degradation of the membrane, such as hygrothermal aging effect on its properties, are particularly necessary. In this work, a thick membrane (Nafion N117, which is always used as an ionic polymer for the PEMFCs, has been analyzed. Experimental investigation is performed for understanding the mechanical endurance of the bare membranes under different loading conditions. Tensile tests are conducted to compare the mechanical property evolution of two kinds of bare-membrane specimens including the dog-bone and the deeply double edge notched (DDEN types. Both dog-bone and DDEN specimens were subjected to a series of degradation tests with different cycling times and wide humidity ranges. The tensile tests are repeated for both kinds of specimens to assess the strain-stress relations. Furthermore, Fourier transform infrared spectroscopy (FT-IR, X-ray diffraction (XRD and Scanning electron microscope (SEM observation and water absorption measurement were conducted to speculate the cause of this variation. The initial cracks along with the increasing of bound water content were speculated as the primary cause.

  4. Investigation of GDL compression effects on the performance of a PEM fuel cell cathode by lattice Boltzmann method

    Science.gov (United States)

    Molaeimanesh, G. R.; Nazemian, M.

    2017-08-01

    Proton exchange membrane (PEM) fuel cells with a great potential for application in vehicle propulsion systems will have a promising future. However, to overcome the exiting challenges against their wider commercialization further fundamental research is inevitable. The effects of gas diffusion layer (GDL) compression on the performance of a PEM fuel cell is not well-recognized; especially, via pore-scale simulation technique capturing the fibrous microstructure of the GDL. In the current investigation, a stochastic microstructure reconstruction method is proposed which can capture GDL microstructure changes by compression. Afterwards, lattice Boltzmann pore-scale simulation technique is adopted to simulate the reactive gas flow through 10 different cathode electrodes with dissimilar carbon paper GDLs produced from five different compression levels and two different carbon fiber diameters. The distributions of oxygen mole fraction, water vapor mole fraction and current density for the simulated cases are presented and analyzed. The results of simulations demonstrate that when the fiber diameter is 9 μm adding compression leads to lower average current density while when the fiber diameter is 7 μm the compression effect is not monotonic.

  5. Energy dispersive X-ray diffraction applied to laboratory investigation on proton exchange membrane water content in working fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Isopo, A.; Rossi Albertini, V. [Istituto di Struttura della Materia - CNR, Roma (Italy); Nobili, F. [Scuola di Scienze e Tecnologie - Sezione Chimica, Universita degli Studi di Camerino (Italy)

    2012-10-15

    An original method, based on the energy-dispersive X-ray diffraction, has been recently proposed as a possible laboratory tool to accomplish long time resolved investigation of the water content in a proton exchange membrane fuel cell. However, this method has never been applied to a real working fuel cell. Therefore, a clear comprehension of its effectiveness in terms of relevant parameters such as time and space resolution, sensitivity, and reproducibility has not yet been achieved. In this paper, all these aspects are discussed and clarified. In order to focus on the method overall effectiveness and on the extent of possible improvements, a basic experimental configuration for both the electrochemical station and the X-ray equipment has been set. The method is described with particular attention to its operating principle and to the evaluation of the errors introduced in data assessment. Finally, applications to some model experiments, in particular working states of the device, are provided and the obtained results are discussed. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Modelling Accident Tolerant Fuel Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Hales, Jason Dean [Idaho National Laboratory; Gamble, Kyle Allan Lawrence [Idaho National Laboratory

    2016-05-01

    The catastrophic events that occurred at the Fukushima-Daiichi nuclear power plant in 2011 have led to widespread interest in research of alternative fuels and claddings that are proposed to be accident tolerant. The United States Department of Energy (DOE) through its Nuclear Energy Advanced Modeling and Simulation (NEAMS) program has funded an Accident Tolerant Fuel (ATF) High Impact Problem (HIP). The ATF HIP is a three-year project to perform research on two accident tolerant concepts. The final outcome of the ATF HIP will be an in-depth report to the DOE Advanced Fuels Campaign (AFC) giving a recommendation on whether either of the two concepts should be included in their lead test assembly scheduled for placement into a commercial reactor in 2022. The two ATF concepts under investigation in the HIP are uranium silicide fuel and iron-chromium-aluminum (FeCrAl) alloy cladding. Utilizing the expertise of three national laboratory participants (Idaho National Laboratory, Los Alamos National Laboratory, and Argonne National Laboratory), a comprehensive multiscale approach to modeling is being used that includes atomistic modeling, molecular dynamics, rate theory, phase-field, and fuel performance simulations. Model development and fuel performance analysis are critical since a full suite of experimental studies will not be complete before AFC must prioritize concepts for focused development. In this paper, we present simulations of the two proposed accident tolerance fuel systems: U3Si2 fuel with Zircaloy-4 cladding, and UO2 fuel with FeCrAl cladding. Sensitivity analyses are completed using Sandia National Laboratories’ Dakota software to determine which input parameters (e.g., fuel specific heat) have the greatest influence on the output metrics of interest (e.g., fuel centerline temperature). We also outline the multiscale modelling approach being employed. Considerable additional work is required prior to preparing the recommendation report for the Advanced

  7. Investigation of Chronic Toxic and Carcinogenic Effects of Gasoline Engine Exhausts Deriving from Fuel without and with Ferrocene Additive.

    Science.gov (United States)

    Peters, L; Ernst, H; Koch, W; Bartsch, W; Bellmann, B; Creutzenberg, O; Hoymann, H G; Dasenbrock, C; Heinrich, U

    2000-01-01

    Chronic toxic and carcinogenic effects of gasoline engine exhaust inhalation were investigated in rats. The exhaust from the combustion of commercial fuel containing 30 ppm ferrocene additive was compared to exhaust from the same fuel without ferrocene. This study was part of a procedure to get a special authorization for the use of ferrocene as gasoline additive according to the German Gasoline Lead Act. To generate the exhausts, pairs of engines of the same type and age were operated on computer-controlled test benches in a combined urban-freeway driving cycle. The engines were equipped with three-way catalysts and lambda sensors. Rats inhaled the exhausts after dilution at ratios of about 1.20 and 1:40 for 18 h/day, 5 days/wk for 12 mo (chronic toxicity study) or for 24 mo followed by 6 mo of clean air (carcinogenicity study). The limiting factor for the exhaust concentration was the relative humidity of the exposure atmosphere. At defined intervals, body weight and food consumption, parameters of clinical chemistry, hematology, bronchoalveolar lavage (BAL), and mechanical lung function were measured, as well as lung clearance and particle retention in the lungs. In the high-dose groups and the controls the complete organ/tissue spectrum was investigated histopathologically, and in the low-dose groups the respiratory tract. Only slight exposure-related effects could be detected, like a loss in the background iron content of the cell pellet of the bronchoalveolar lavage fluid and cytoplasmic inclusions and goblet-cell hyperplasias in the nasal cavity. Between the clean-air controls and the exhaust-exposed groups, no exposure-related differences occurred in body weight development, mortality incidences, or any of the clinical investigations. Ninety-two to 94% of the animals developed age-related tumors, predominantly in the mammary glands, uterus, adrenals, thyroid, and pituitary. In the respiratory tract a total of five tumors was found: one in the controls and

  8. An Investigation of the Ionospheric Disturbances Due to the 2014 Sudden Stratospheric Warming Events Over Brazilian Sector

    Science.gov (United States)

    de Jesus, R.; Batista, I. S.; Jonah, O. F.; de Abreu, A. J.; Fagundes, P. R.; Venkatesh, K.; Denardini, C. M.

    2017-11-01

    The present study investigates the ionospheric F region response in the Brazilian sector due to sudden stratospheric warming (SSW) events of 2014. The data used for this work are obtained from GPS receivers and magnetometer measurements during day of year (DOY) 01 to 120, 2014 at different stations in the equatorial and low-latitude regions in the Brazilian sector. In addition, the data obtained from Communication/Navigation Outage Forecasting System satellites during DOY 01 to 75 of 2014 are used. The main novelty of this research is that, during the 2014 SSW events, daytime vertical total electron content (VTEC) shows a strong increase on the order of about 23% and 11% over the equatorial and low-latitude regions, respectively. We also observed that the nighttime VTEC (SSW days) is increased by 8% and 33% over equatorial and low-latitude regions, respectively. The magnetometer measurements show a strong counterelectrojet during the SSW days. The results show an amplification of the 0.5 day and 2-16 day periods in the VTEC and equatorial electrojet during the SSWs. The occurrences of ionospheric irregularities during the SSW events are around 84% and 53% in the equatorial and low-latitude regions, respectively, which is less frequent when compared with those during the pre-SSW periods.

  9. A fundamental investigation into the relationship between lubricant composition and fuel ignition quality

    KAUST Repository

    Kuti, Olawole Abiola

    2015-11-01

    A fundamental experiment involving the use of an ignition quality tester (IQT) was carried out to elucidate the effects of lubricant oil composition which could lead to low speed pre-ignition (LSPI) processes in direct injection spark ignition (DISI) engines. Prior to the IQT tests, lubricant base oils were analyzed using ultra-high resolution mass spectrometry to reveal their molecular composition. High molecular-weight hydrocarbons such as nC16H34, nC17H36, and nC18H38 were selected as surrogates of lubricant base oil constituents, and then mixed with iso-octane (iC8H18-gasoline surrogate) in proportions of 1 vol.% (iC8H18 = 99 vol.%) and 10 vol.% (iC8H18 = 90 vol.%) for the IQT experiments. In addition, lubricant base oils such as SN100 (Group I) and HC4 and HC6 (Group III) and a fully formulated lubricant (SAE 20W50) were mixed with iso-octane in the same proportions. The IQT results were conducted at an ambient pressure of 15 bar and a temperature range of 680-873 K. In the temperature range of 710-850 K, the addition of 10 vol.% base oils surrogates, base oils, and lubricating oil to the 90 vol.% iC8H18 reduces the average total ignition delay time by up to 54% for all mixtures, while the addition of 1 vol.% to 99 vol.% iC8H18 yielded a 7% reduction within the same temperature range. The shorter total ignition delay was attributed to the higher reactivity of the lubricant base oil constituents in the fuel mixtures. A correlation between reactivity of base oils and their molecular composition was tentatively established. These results suggest that the lubricants have the propensity of initiating LSPI in DISI engines. Furthermore, similar results for n-alkanes, lubricant base oils, and fully formulated commercial lubricants suggest that it is the hydrocarbon fraction that contributes primarily to enhanced reactivity, and not the inorganic or organometallic additives. © 2015 Elsevier Ltd. All rights reserved.

  10. Operando X-ray investigation of solid oxide fuel cell model electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, Sergey Aleksandrovic

    2017-04-15

    A detailed study of three solid oxide fuel cells (SOFCs) related model systems is presented in this work with the aim of the better understanding of the structural changes in cell components associated with their operation. The first model system is an La{sub 0.6}Sr{sub 0.4}CoO{sub 3-d} (LSC) on yttria-stabilized zirconia (YSZ). Changes in the YSZ(100) single crystal surface structure buried under the squared LSC microelectrode were studied at a synchrotron under operational conditions. High flux photon beam at the synchrotron allowed access to the LSC/YSZ interface. Structural information from the substrate surface at an atomic scale was acquired. Element-specific anomalous XRD data allowed to distinguish between Y and Zr scattering contributions. For the first time, it was shown that the Y cation concentration at the electrode/electrolyte interface strongly depends on the sample environment and the applied potential. The second model system is a Pt/YSZ. Buried YSZ(111) surface and dense Pt film morphology changes under operational conditions were addressed. High-energy X-rays were necessary to collect surface-sensitive information from the interface due to highly absorbing Pt film. The main conclusion is - under conditions applied, the YSZ single crystal surface remains stable at an atomic level. A nagging topic of the Pt ''phase oxide'' formation at the Pt/YSZ interface during anodic polarization was also raised. Although XRD data did not show a clear evidence of PtO{sub x} presence at the interface, energy-dispersive X-ray analysis of the film cross-cut profile after the synchrotron experiment revealed distinct oxygen signal from delaminated parts of the film. Last but not least, the structure of a ZrO{sub 2} ultrathin film grown on a Pt{sub 3}Zr(0001) single crystal was studied in ultra-high vacuum for the first time be means of SXRD. This model system is aiming to improve understanding of the electrolyte materials based on ZrO{sub 2} (e

  11. The Campanian Ignimbrite Eruption, Heinrich Event 4, and palaeolithic change in Europe: A high-resolution investigation

    Science.gov (United States)

    Fedele, Francesco G.; Giaccio, Biagio; Isaia, Roberto; Orsi, Giovanni

    The Campanian Ignimbrite (CI) eruption from the Phlegraean Fields Caldera, southern Italy, represents one of the largest late Quaternary volcanic event. Its recent dating at 39,280±110 yr BP draws attention to the occurrence of this volcanic catastrophe during a time interval characterized by biocultural modifications in western Eurasia. These included the Middle to Upper Palaeolithic transition and the supposed change from Neandertal to "modern" Homo sapiens anatomy, a subject of continuing investigation and controversy. The paper aims to clarify the position and relevance of the CI event in this context. At several archaeological sites of southeastern Europe, the CI ash separates the cultural layers containing Middle Palaeolithic and/or "Earliest Upper Palaeolithic" assemblages from the layers in which Upper Palaeolithic industries occur. At the same sites the CI tephra coincides with a long interruption of occupation. The palaeclimatic records containing the CI products show that the eruption occurred just at the beginning of Heinrich Event 4 (HE4), which was characterized by extreme climatic conditions, compared to the other HEs. From the observation of this concurrence of factors, we advance the hypothesis of a positive climate-volcanism feedback triggered by the co-occurrence of the CI eruption and HE4 onset. Both the environmental and cultural data available for a c.5000-year interval on either side of the event, suggest that a reappraisal of the identity and destiny of the archaeological industries representing the so-called Middle to Upper Palaeolithictransition is in order. This might force a reassessment of the Upper Palaeolithic notion as traditionally employed.

  12. Investigation of neutronic and safety parameters variation in 5 MW research reactor due to U{sub 3}O{sub 8}Al fuel conversion to ThO{sub 2} + U{sub 3}O{sub 8}Al

    Energy Technology Data Exchange (ETDEWEB)

    Gholamzadeh, Zohreh; Alipoor, Zahra; Mirvakili, Seyed Mohammad [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Reactor Research School; Feghhi, Seyed Amir Hossein [Shahid Beheshti Univ., Tehran (Iran, Islamic Republic of). Dept. of Radiation Application; Vahedi, M.; Bagheri, H. [Univ. of Science and Technology, Tehran (Iran, Islamic Republic of). Energy Dept.; Tenreiro, Claudio [Talca Univ. (Chile). Energy Dept.

    2017-05-15

    Thorium-based fuels could comprise several advantages and are being investigated as a potentially competitive option with uranium-based fuels for research or power reactors. The present study investigates computationally the application of two different thorium-based fuels in a research reactor. Void and temperature reactivity coefficients, safety factor, power peaking factor, neutron generation time, effective delayed neutron fraction and {sup 135}Xe worth parameter were investigated for the fuel conversions. The results showed both the investigated fuels would not significantly disturb neutronic and safety parameters of the modeled core in comparison with its routine fuel loading. However, 235-enriched thorium based fuel concluded in noticeably reduction of High Level Waste (HLW) but 233-enriched type could be taken in attention because of its longer fuel cycle (∝15 %) and integrated neutron flux (∝23 %).

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

    Directory of Open Access Journals (Sweden)

    Voytkov Ivan V.

    2016-01-01

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

  14. Experimental investigation of urea injection parameters influence on NOx emissions from blended biodiesel-fueled diesel engines.

    Science.gov (United States)

    Mehregan, Mina; Moghiman, Mohammad

    2017-11-27

    The present work submits an investigation about the effect of urea injection parameters on NOx emissions from a four-stroke four-cylinder diesel engine fueled with B20 blended biodiesel. An L9(34) Taguchi orthogonal array was used to design the test plan. The results reveal that increasing urea concentration leads to lower NOx emissions. Urea flow rate increment has the same influence on NOx emission. The same result is obtained by an increase in spray angle. Also, according to the analysis of variance (ANOVA), urea concentration and then urea flow rate are the most effective design parameters on NOx emissions, while spray angle and mixing length have less influence on this pollutant emission. Finally, since the result of confirmation test is in good agreement with the predicted value based on the Taguchi technique, the predictive capability of this method in the present study could be deduced.

  15. Cultural Resource Investigation for the Materials and Fuels Complex Wastewater System Upgrade at the Idaho National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Brenda R. Pace; Julie B raun Williams; Hollie Gilbert; Dino Lowrey; Julie Brizzee

    2010-05-01

    The Materials and Fuels Complex (MFC) located in Bingham County at the Idaho National Laboratory (INL) in southeastern Idaho is considering several alternatives to upgrade wastewater systems to meet future needs at the facility. In April and May of 2010, the INL Cultural Resource Management Office conducted archival searches, archaeological field surveys, and coordination with the Shoshone-Bannock Tribes to identify cultural resources that may be adversely affected by the proposed construction and to provide recommendations to protect any resources listed or eligible for listing on the National Register of Historic Places. These investigations showed that one National Register-eligible archaeological site is located on the boundary of the area of potential effects for the wastewater upgrade. This report outlines protective measures to help ensure that this resource is not adversely affected by construction.

  16. Investigating a two-component model of solid fuel organic aerosol in London: processes, PM1 contributions, and seasonality

    Science.gov (United States)

    Young, D. E.; Allan, J. D.; Williams, P. I.; Green, D. C.; Harrison, R. M.; Yin, J.; Flynn, M. J.; Gallagher, M. W.; Coe, H.

    2015-03-01

    Solid fuel emissions, including those from biomass burning, are increasing in urban areas across the European Union due to rising energy costs and government incentives to use renewable energy sources for heating. In order to help protect human health as well as to improve air quality and pollution abatement strategies, the sources of combustion aerosols, their contributions, and the processes they undergo need to be better understood. A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was therefore deployed at an urban background site between January and February 2012 to investigate solid fuel organic aerosols (SFOA) in London. The variability of SFOA was examined and the factors governing the split between the two SFOA factors derived from Positive Matrix Factorisation (PMF) were assessed. The concentrations of both factors were found to increase during the night and during cold periods, consistent with domestic space heating activities. The split between the two factors is likely governed predominantly by differences in burn conditions where SFOA1 best represents more efficient burns and SFOA2 best represents less efficient burns. The differences in efficiency may be due to burner types or burn phase, for example. Different fuel types and levels of atmospheric processing also likely contribute to the two factors. As the mass spectral profile of SFOA is highly variable, the findings from this study may have implications for improving future source apportionment and factorisation analyses. During the winter, SFOA was found to contribute 38% to the total non-refractory submicron organic aerosol (OA) mass, with similar contributions from both SFOA factors (20% from SFOA1 and 18% from SFOA2). A similar contribution of SFOA was derived for the same period from a compact time-of-flight AMS (cToF-AMS), which measured for a full calendar year at the same site. The seasonality of SFOA was investigated using the year-long data set where concentrations

  17. Perceiving control over aversive and fearful events can alter how we experience those events: an investigation of time perception in spider-fearful individuals

    Directory of Open Access Journals (Sweden)

    Simona eBuetti

    2012-09-01

    Full Text Available We used a time perception task to study the effects of the subjective experience of control on emotion and cognitive processing. This task is uniquely sensitive to the emotionality of the stimuli: high-arousing negative stimuli are perceived as lasting longer than high-arousing positive events, while the opposite pattern is observed for low-arousing stimuli. We evaluated the temporal distortions of emotionally-charged events in non-anxious (Experiments 1 and 5 and spider-fearful individuals (Experiments 2-4. Participants were shown images of varying durations between 400 and 1600 ms and were asked to report if the perceived duration of the image seemed closer to a short (400 ms or to a long (1600 ms standard duration. Our results replicate previous findings showing that the emotional content of the image modulated the perceived duration of that image. More importantly, we studied whether giving participants the illusion that they have some control over the emotional content of the images could eliminate this temporal distortion. Results confirmed this hypothesis, even though our participant population was composed of highly-reactive emotional individuals (spider fearful facing fear-related images (spiders. Further, we also showed that under conditions of little-to-no control, spider-fearful individuals perceive temporal distortions in a distinct manner from non-anxious participants: the duration of events was entirely determined by the valence of the events, rather than by the typical valence x arousal interaction. That is, spider-fearful participants perceived negative events as lasting longer than positive events, regardless of their level of arousal. Finally, we also showed that under conditions of cognitive dissonance, control can eliminate temporal distortions of low arousal events, but not of high-arousing events, providing an important boundary condition to the otherwise positive effects of control on time estimation.

  18. Theoretical investigations on improving performance of cooling systems for fuel cell vehicles; Theoretische Untersuchungen zur Kuehlleistungssteigerung durch innovative Kuehlsysteme fuer Brennstoffzellen-Elektrofahrzeuge

    Energy Technology Data Exchange (ETDEWEB)

    Reichler, Mark

    2008-04-01

    In this work theoretical investigations are carried out for cooling systems, which are used in fuel cell vehicles. This work focuses mainly on the capability of increasing the heat rejection rate by using new alternative cooling systems and by improving the conventional cooling system. Fuel cell vehicles have a higher demand of heat rejection to the ambient than comparable vehicles with combustion engine. The performance of conventional liquid cooling systems, especially at high loads and high ambient temperatures, is often not sufficient anymore. Hence, cooling systems with improved performance are necessary for fuel cell vehicles. The investigations in this work are based on DaimlerChrysler's ''A-Class'' having a PEM-Fuel Cell system integrated. Specific computational models are developed for radiators and condensers to evaluate the performance of different cooling concepts. The models are validated with experimental data. Based on an intensive investigation in the open literature the state of the art of cooling systems for fuel cell vehicles is depicted. Furthermore new cooling concepts as an alternative to the liquid cooling system are presented. The method of cooling the fuel cell by using two-phase transition shows the greatest capability to increase the cooling performance. Hence, this concept is investigated in detail. Two different concepts with three different refrigerants (R113, R245fa und R236fa) are analyzed. Cooling performance of this concept shows improvement of 18.2 up to 32.6 % compared to the conventional liquid cooling system. Thus, a two phase cooling system represents an alternative cooling system for fuel cell vehicles, which should be closer investigated by experiments. (orig.)

  19. Fuel flexible fuel injector

    Science.gov (United States)

    Tuthill, Richard S; Davis, Dustin W; Dai, Zhongtao

    2015-02-03

    A disclosed fuel injector provides mixing of fuel with airflow by surrounding a swirled fuel flow with first and second swirled airflows that ensures mixing prior to or upon entering the combustion chamber. Fuel tubes produce a central fuel flow along with a central airflow through a plurality of openings to generate the high velocity fuel/air mixture along the axis of the fuel injector in addition to the swirled fuel/air mixture.

  20. Investigation of Novel Electrocatalysts for Metal Supported Solid Oxide Fuel Cells - Ru:GDC

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Nielsen, Jimmi; Thydén, Karl Tor Sune

    2015-01-01

    ]. In the present study, MS-SOFCs infiltrated with Ru:GDC electrocatalyst are investigated. The Ru:GDC precursor solution was infiltrated into the anode backbone and heat treated in air at different temperatures to remove the organic materials while preventing the corrosion of the metal particles. The morphology...... the development of metal supported SOFCs (MS-SOFCs) by using the cheaper support materials such as stainless steel. Furthermore, MS-SOFCs offer some advantages compared to conventional electrode and electrolyte supported SOFCs such as higher thermal conductivity, ductility in support, which are advantageous...

  1. Microscale In Vitro Assays for the Investigation of Neutral Red Retention and Ethoxyresorufin-O-Deethylase of Biofuels and Fossil Fuels

    DEFF Research Database (Denmark)

    Heger, Sebastian; Bluhm, Kerstin; Brendt, Julia

    2016-01-01

    Only few information on the potential toxic effectiveness of biofuels are available. Due to increasing worldwide demand for energy and fuels during the past decades, biofuels are considered as a promising alternative for fossil fuels in the transport sector. Hence, more information on their hazard......, ecotoxicological methods are applied to gain information on potential adverse environmental effects of biofuels at an early phase of their development. In the present study, three potential biofuels, ethyl levulinate, 2-methyltetrahydrofuran and 2-methylfuran were tested. Furthermore, we investigated a fossil...... gasoline fuel, a fossil diesel fuel and an established biodiesel. Two in vitro bioassays, one for assessing cytotoxicity and one for aryl hydrocarbon receptor agonism, so called dioxin-like activity, as measured by Ethoxyresorufin-O-Deethylase, were applied using the permanent fish liver cell line RTL-W1...

  2. Investigating the knowledge and preparedness of proximal residents to a general-emergency event at the Koeberg Nuclear Power Station

    Directory of Open Access Journals (Sweden)

    Alberto P. Francioli

    2016-01-01

    Full Text Available Ward 23 in the City of Cape Town South Africa is situated within 16 km of Koeberg Nuclear Power Station (KNPS. Massive investments were made to provide the 13 800 residents of Ward 23 with information on emergency preparedness and evacuation procedures in case of a general-emergency event at KNPS. However, it is not known whether these efforts to inform and prepare the proximal residents for a general emergency have been effective or not. The objective of this study was to investigate the level of knowledge of and preparedness for an emergency exhibited by residents of Ward 23. Data was collected through the distribution of semi-structured questionnaires to 204 residents at the study site to ascertain their views on the provision and accessibility of emergency information and to find out whether they utilised this information to prepare themselves. The results revealed that the majority of interviewed residents had very poor knowledge concerning emergency procedures, and few had made any effort to prepare themselves. The majority of better-informed and prepared residents tended to reside closer to KNPS. The poor levels of knowledge and preparedness are attributed to residents’ lack of awareness concerning the availability of information, misconceptions regarding a nuclear hazard and a general emergency event or a lack of incentive to inform themselves due to a perceived high sense of security and the improbability of such an event occurring. To improve resident knowledge and preparedness, efforts should be made to advertise the availability and importance of such emergency information and enhance incentives for residents to inform themselves.

  3. Investigating the impact of Lake Agassiz drainage routes on the 8.2 ka cold event with a climate model

    Directory of Open Access Journals (Sweden)

    Y.-X. Li

    2009-08-01

    Full Text Available The 8.2 ka event is the most prominent abrupt climate change in the Holocene and is often believed to result from catastrophic drainage of proglacial lakes Agassiz and Ojibway (LAO that routed through the Hudson Bay and the Labrador Sea into the North Atlantic Ocean, and perturbed Atlantic meridional overturning circulation (MOC. One key assumption of this triggering mechanism is that the LAO freshwater drainage was dispersed over the Labrador Sea. Recent data, however, show no evidence of lowered δ18O values, indicative of low salinity, from the open Labrador Sea around 8.2 ka. Instead, negative δ18O anomalies are found close to the east coast of North America, extending as far south as Cape Hatteras, North Carolina, suggesting that the freshwater drainage may have been confined to a long stretch of continental shelf before fully mixing with North Atlantic Ocean water. Here we conduct a sensitivity study that examines the effects of a southerly drainage route on the 8.2 ka event with the ECBilt-CLIO-VECODE model. Hosing experiments of four routing scenarios, where freshwater was introduced to the Labrador Sea in the northerly route and to three different locations along the southerly route, were performed to investigate the routing effects on model responses. The modeling results show that a southerly drainage route is possible but generally yields reduced climatic consequences in comparison to those of a northerly route. This finding implies that more freshwater would be required for a southerly route than for a northerly route to produce the same climate anomaly. The implicated large amount of LAO drainage for a southerly routing scenario is in line with a recent geophysical modelling study of gravitational effects on sea-level change associated with the 8.2 ka event, which suggests that the volume of drainage might be larger than previously estimated.

  4. Microscale In Vitro Assays for the Investigation of Neutral Red Retention and Ethoxyresorufin-O-Deethylase of Biofuels and Fossil Fuels.

    Directory of Open Access Journals (Sweden)

    Sebastian Heger

    Full Text Available Only few information on the potential toxic effectiveness of biofuels are available. Due to increasing worldwide demand for energy and fuels during the past decades, biofuels are considered as a promising alternative for fossil fuels in the transport sector. Hence, more information on their hazard potentials are required to understand the toxicological impact of biofuels on the environment. In the German Cluster of Excellence "Tailor-made Fuels from Biomass" design processes for economical, sustainable and environmentally friendly biofuels are investigated. In an unique and interdisciplinary approach, ecotoxicological methods are applied to gain information on potential adverse environmental effects of biofuels at an early phase of their development. In the present study, three potential biofuels, ethyl levulinate, 2-methyltetrahydrofuran and 2-methylfuran were tested. Furthermore, we investigated a fossil gasoline fuel, a fossil diesel fuel and an established biodiesel. Two in vitro bioassays, one for assessing cytotoxicity and one for aryl hydrocarbon receptor agonism, so called dioxin-like activity, as measured by Ethoxyresorufin-O-Deethylase, were applied using the permanent fish liver cell line RTL-W1 (Oncorhynchus mykiss. The special properties of these fuel samples required modifications of the test design. Points that had to be addressed were high substance volatility, material compatibility and low solubility. For testing of gasoline, diesel and biodiesel, water accommodated fractions and a passive dosing approach were tested to address the high hydrophobicity and low solubility of these complex mixtures. Further work has to focus on an improvement of the chemical analyses of the fuel samples to allow a better comparison of any effects of fossil fuels and biofuels.

  5. Microscale In Vitro Assays for the Investigation of Neutral Red Retention and Ethoxyresorufin-O-Deethylase of Biofuels and Fossil Fuels.

    Science.gov (United States)

    Heger, Sebastian; Bluhm, Kerstin; Brendt, Julia; Mayer, Philipp; Anders, Nico; Schäffer, Andreas; Seiler, Thomas-Benjamin; Hollert, Henner

    Only few information on the potential toxic effectiveness of biofuels are available. Due to increasing worldwide demand for energy and fuels during the past decades, biofuels are considered as a promising alternative for fossil fuels in the transport sector. Hence, more information on their hazard potentials are required to understand the toxicological impact of biofuels on the environment. In the German Cluster of Excellence "Tailor-made Fuels from Biomass" design processes for economical, sustainable and environmentally friendly biofuels are investigated. In an unique and interdisciplinary approach, ecotoxicological methods are applied to gain information on potential adverse environmental effects of biofuels at an early phase of their development. In the present study, three potential biofuels, ethyl levulinate, 2-methyltetrahydrofuran and 2-methylfuran were tested. Furthermore, we investigated a fossil gasoline fuel, a fossil diesel fuel and an established biodiesel. Two in vitro bioassays, one for assessing cytotoxicity and one for aryl hydrocarbon receptor agonism, so called dioxin-like activity, as measured by Ethoxyresorufin-O-Deethylase, were applied using the permanent fish liver cell line RTL-W1 (Oncorhynchus mykiss). The special properties of these fuel samples required modifications of the test design. Points that had to be addressed were high substance volatility, material compatibility and low solubility. For testing of gasoline, diesel and biodiesel, water accommodated fractions and a passive dosing approach were tested to address the high hydrophobicity and low solubility of these complex mixtures. Further work has to focus on an improvement of the chemical analyses of the fuel samples to allow a better comparison of any effects of fossil fuels and biofuels.

  6. The investigation of form and processes in the coastal zone under extreme storm events - the case study of Rethymno, Greece

    Science.gov (United States)

    Afentoulis, Vasileios; Mohammadi, Bijan; Tsoukala, Vasiliki

    2017-04-01

    Coastal zone is a significant geographical and particular region, since it gathers a wide range of social-human's activities and appears to be a complex as well as fragile system of natural variables. Coastal communities are increasingly at risk from serious coastal hazards, such as shoreline erosion and flooding related to extreme hydro-meteorological events: storm surges, heavy precipitation, tsunamis and tides. In order to investigate the impact of these extreme events on the coastal zone, it is necessary to describe the driving mechanisms which contribute to its destabilization and more precisely the interaction between the wave forces and the transport of sediment. The aim of the present study is to examine the capability of coastal zone processes simulation under extreme wave events, using numerical models, in the coastal area of Rethymno, Greece. Rethymno city is one of the eleven case study areas of PEARL (Preparing for Extreme And Rare events in coastal regions) project, an EU funded research project, which aims at developing adaptive risk management strategies for coastal communities focusing on extreme hydro-meteorological events, with a multidisciplinary approach integrating social, environmental and technical research and innovation so as to increase the resilience of coastal regions all over the world. Within this framework, three different numerical models have been used: the MIKE 21 - DHI, the XBeach model and a numerical formulation for sea bed evolution, developed by Afaf Bouharguane and Bijan Mohammadi (2013). For the determination of the wave and hydrodynamic conditions, as well as the assessment of the sediment transport components, the MIKE 21 SW and the MIKE 21 FM modules have been applied and the bathymetry of Rethymno is arranged into a 2D unstructured mesh. This method of digitalization was selected because of its ability to easily represent the complex geometry of the coastal zone. It allows smaller scale wave characteristics to be

  7. INVESTIGATION OF MAIZE COBS CRUSHING - PREPARATION FOR USE AS A FUEL

    Directory of Open Access Journals (Sweden)

    Savo Bojić

    2011-01-01

    Full Text Available Maize crop residues have great significance, particularly in developing countries, where the harvest of maize ears and their natural drying is widely applied. After drying and grain threshing, maize cobs are available for energetic use on farmers' yards. Shortcomings for their energetic utilization by combustion, in comparison with wood, are higher contents of potassium, chlorine and nitrogen, and lower ash softening point. Tests in small wood chip boilers showed that the size of maize cobs should be reduced in order to facilitate better combustion and feeding with commonly used screw conveyors. Desirable length of particles should be 1-1.5 of their diameter. Within the framework of the Eureka project, a low-cost maize cobs crusher was developed and tested. It consists of a drum with six rows of knives, stationary comb-like knives and a screen situated below the drum. The test resulted with working parameters that enable appropriate size reduction. Analyses of crushed material showed that over 80% of particles were in the range of 3.15-45 mm, less than 1% smaller than 1 mm, and less than 1% larger than 63 mm. This granulation is comparable with size class P45 for wood chips in accordance with standard DIN CEN/TS 14961. Further investigations should focus on improving the combustion facilities, in order to avoid formation of ash slag, and keeping exhaust gas characteristics within values defined by legislation.

  8. Investigating Surface and Near-Surface Bushfire Fuel Attributes: A Comparison between Visual Assessments and Image-Based Point Clouds.

    Science.gov (United States)

    Spits, Christine; Wallace, Luke; Reinke, Karin

    2017-04-20

    Visual assessment, following guides such as the Overall Fuel Hazard Assessment Guide (OFHAG), is a common approach for assessing the structure and hazard of varying bushfire fuel layers. Visual assessments can be vulnerable to imprecision due to subjectivity between assessors, while emerging techniques such as image-based point clouds can offer land managers potentially more repeatable descriptions of fuel structure. This study compared the variability of estimates of surface and near-surface fuel attributes generated by eight assessment teams using the OFHAG and Fuels3D, a smartphone method utilising image-based point clouds, within three assessment plots in an Australian lowland forest. Surface fuel hazard scores derived from underpinning attributes were also assessed. Overall, this study found considerable variability between teams on most visually assessed variables, resulting in inconsistent hazard scores. Variability was observed within point cloud estimates but was, however, on average two to eight times less than that seen in visual estimates, indicating greater consistency and repeatability of this method. It is proposed that while variability within the Fuels3D method may be overcome through improved methods and equipment, inconsistencies in the OFHAG are likely due to the inherent subjectivity between assessors, which may be more difficult to overcome. This study demonstrates the capability of the Fuels3D method to efficiently and consistently collect data on fuel hazard and structure, and, as such, this method shows potential for use in fire management practices where accurate and reliable data is essential.

  9. Investigation of the Effect of Control Measures on Reduction of Risk Events in an Edible Oil Factory in Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Malihe Kolahdouzi

    2017-07-01

    Full Text Available Background & Aims of the Study: Identification of hazards is one of the first goals of risk analysis. Failure mode and effect analysis method (FMEA is universally defined as efficient procedures for finding potential failures aimed to remove or decrease the risk which is related to them. This study aimed to investigate the effect of control measures on reduction of risk events in an edible oil factory in Tehran. Methods: This cross-sectional study was conducted in an edible oil factory in Tehran, Iran. For this, a four-member team of safety engineer experts was formed. Some factory units were selected randomly. After that, in all units, probability, severity and detection probability of hazards in all processes and tasks were assessed based on FMEA method. Regarding to the RPN, some control measures were taken to reduce the risk of events. After 9 months, risk assessment was repeated; primary and secondary RPNs were compared with each other to investigate the effect of interventions. Results: The results showed that highest and lowest probability of hazard were related to installation and can production unit, respectively. The highest and lowest severity of hazard were related to tool and can production unit, respectively. There was a significant difference between the probability of hazard in can-making and filling units, before and after the interventions. There was a significant difference between the severity of hazard in can-making, filling and neutralization units, before and after the interventions. As well, total probability, severity and RPN had a significant difference in all parts of the factory before and after the interventions. Conclusions: According to the results of this study and the overall risk reduction caused by interventional measures, it can be concluded that, FMEA is a successful method for identifying hazards and risk control measures.

  10. Investigating the feasibility of growing algae for fuel in Southern nevada

    Science.gov (United States)

    Moazeni, Faegheh

    Microalgae capable of growing in waste are adequate to be mass-cultivated for biodiesel, avoiding fertilizers and clean water, two obstacles to sustainability of the feedstock production. This study replaces fertilizers and clean water with waste products. The investigated wastes include (1) the liquid fraction of sewage after solids and particles are removed, known as centrate, and (2) algal biomass residue, i.e. the algae remaining at the end of the lipids extraction process at biofuel plants. These wastes contain sufficient amount of nitrogen and phosphorus required for algal growth. This study proposes a system in which centrate would be used as an initial source of water and nutrients for microalgal growth. The generated biomass waste can be continuously recycled, serving as a fertilizer. If so desired, the centrate can be reverted back into the system from time to time as a nutrition supplement and as a make-up water source, particularly in open ponds that face evaporation. Of the six studied algae, i.e. Chlorella sorokiniana, Encyonema caespitosum, Nitzschia thermalis, Scenedesmus sp., Synechocystis sp., and Limnothrix sp., mostly isolated from the habitats influenced by municipal wastewater in and around the Las Vegas Valley, two green algae were eligible. In the laboratory, the green algae C. sorokiniana and Scenedesmus sp. grew in the media composed of centrate or algal residue faster than in the mineral medium BG11, optimized for algal growth. The enhanced productivity is mainly attributed to the photosynthesis known for mixotrophic process and the presence of organic carbon in the waste which serves as an extra source of energy. Tolerance for hard water and strong light and, in the case of C. sorokiniana , an unusually high optimum temperature between 32 and 35°C are also attributing factors to the enhanced productivity of algae. These studied species are particularly suited for cultivation in their native southwestern United States, particularly

  11. Disagreements between central clinical events committee and site investigator assessments of myocardial infarction end- points in an international clinical trial: Review of the PURSUIT study

    NARCIS (Netherlands)

    K.W. Mahaffey (Kenneth); R.A. Harrington (Robert Alex); K.M. Akkerhuis (Martijn); N.S. Kleiman (Neal); L.G. Berdan (Lisa); B.S. Crenshaw (Brian); B.E. Tardiff (Barbara); C.B. Granger (Christopher); I. DeJong (Ingrid); M. Bhapkar (Manju); P. Widimsky (Petr); R. Corbalon (Ramón); K.L. Lee (Kerry); J.W. Deckers (Jaap); M.L. Simoons (Maarten); E.J. Topol (Eric); R.M. Califf (Robert)

    2001-01-01

    textabstractBackground. Limited information has been published regarding how specific processes for event adjudication can affect event rates in trials. We reviewed nonfatal myocardial infarctions (MIs) reported by site investigators in the international Platelet Glycoprotein IIb/IIIa in Unstable

  12. Disagreements between central clinical events committee and site investigator assessments of myocardial infarction end-points in an international clinical trial: review of the PURSUIT study

    NARCIS (Netherlands)

    K.W. Mahaffey (Kenneth); R.A. Harrington (Robert Alex); N.S. Kleiman (Neal); L.G. Berdan (Lisa); B.S. Crenshaw (Brian); B.E. Tardiff (Barbara); C.B. Granger (Christopher); I. DeJong (Ingrid); M. Bhapkar (Manju); P. Widimsky (Petr); R. Corbalon (Ramón); K.L. Lee (Kerry); J.W. Deckers (Jaap); M.L. Simoons (Maarten); E.J. Topol (Eric); R.M. Califf (Robert); K.M. Akkerhuis (Martijn)

    2001-01-01

    textabstractAbstract: Background Limited information has been published regarding how specific processes for event adjudication can affect event rates in trials. We reviewed nonfatal myocardial infarctions (MIs) reported by site investigators in the international Platelet Glycoprotein IIb/IIIa in

  13. Investigation of emissions characteristics of secondary butyl alcohol-gasoline blends in a port fuel injection spark ignition engine

    Directory of Open Access Journals (Sweden)

    Yusri I.M.

    2017-01-01

    Full Text Available Exhaust emissions especially from light duty gasoline engine are a major contributor to air pollution due to the large number of vehicles on the road. The purpose of this study is to experimentally analyse the exhaust pollutant emissions of a four-stroke port fuel spark ignition engines operating using secondary butyl alcohol–gasoline blends by percentage volume of 5% (GBu5, 10% (GBu10 and 15% (GBu15 of secondary butyl- alcohol (2-butanol additives in gasoline fuels at 50% of wide throttle open. The exhaust emissions characteristics of the engine using blended fuels was compared to the exhaust emissions of the engine with gasoline fuels (G100 as a reference fuels. Exhaust emissions analysis results show that all of the blended fuels produced lower CO by 8.6%, 11.6% and 24.8% for GBu5, GBu10 and GBu15 respectively from 2500 to 4000 RPM, while for HC, both GBu10 and GBu15 were lower than that G100 fuels at all engine speeds. In general, when the engine was operated using blended fuels, the engine produced lower CO and HC, but higher CO2.

  14. Characterization and source regions of 51 high-CO events observed during Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container (CARIBIC) flights between south China and the Philippines, 2005-2008

    Science.gov (United States)

    Lai, S. C.; Baker, A. K.; Schuck, T. J.; Slemr, F.; Brenninkmeijer, C. A. M.; van Velthoven, P.; Oram, D. E.; Zahn, A.; Ziereis, H.

    2011-10-01

    Carbon monoxide (CO) and other atmospheric trace constituents were measured from onboard an Airbus 340-600 passenger aircraft in the upper troposphere (UT) between south China and the Philippines during Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container (CARIBIC) flights from May 2005 until March 2008. A total of 132 events having CO enhancements were observed in the UT over the region during the 81 CARIBIC flights from Frankfurt, Germany, to Manila, Philippines, with a stopover in Guangzhou, China. Among these, 51 high-CO events with enhancements more than 50 ppb above background were observed. For these events enhancements ranged from 52.7 to 221.3 ppb and persisted for 3 to 78 min (˜40 to 1200 km), indicating an influence of strong pollution from biomass/biofuel/fossil fuel burning on the trace gas composition of the UT. Back trajectory analysis shows that south China, the Indochinese Peninsula, and the Philippines/Indonesia are the main source regions of the high-CO events. The composition of air parcels originating from south China was found to be primarily influenced by anthropogenic urban/industrial emissions, while emissions from biomass/biofuel burning contributed substantially to CO enhancements from the Indochinese Peninsula. During the Philippines/Indonesia events, air parcel composition suggests contributions from both biomass/biofuel burning and urban/industrial sources. Long-range transport of air parcels from northeast Asia and India also contributed to CO enhancements in the UT over the region. The general features of regional influence, typical cases, and the contributions of biomass/biofuel burning and anthropogenic emissions are presented and discussed to characterize the air parcels during the observed high-CO events.

  15. Experimental Investigation of Operation of VVER Steam Generator in Condensation Mode in the Event of the Severe Accident

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, Andrey [Institute for Physics and Power Engineering by A.I. Leypunsky, 1 Bondarenko sq. Obninsk, 249033 (Russian Federation)

    2008-07-01

    For new Russian nuclear power plants with VVER-1200 reactor in the event of a beyond design basis accident, provision is made for the use of passive safety systems for necessary core cooling. These safety systems include the passive heat removal system (PHRS). In the case of leakage in the primary circuit this system assures the transition of steam generators (SG) to operation in the mode of condensation of the primary circuit steam. As a result, the condensate from SG arrives at the core providing its additional cooling. To investigate the condensation mode of VVER SG operation, a large scale HA2M-SG test facility was constructed. The rig incorporates: buffer tank, SG model with scale is 1:46, PHRS heat exchanger. Experiments at the test facility have been performed to investigate condensation mode of operation of SG model at the pressure 0.4 MPa, correspond to VVER reactor pressure at the last stage of the beyond design basis accident. The report presents the test procedure and the basic obtained test results. (authors)

  16. Biobutanol as Fuel for Direct Alcohol Fuel Cells-Investigation of Sn-Modified Pt Catalyst for Butanol Electro-oxidation.

    Science.gov (United States)

    Puthiyapura, Vinod Kumar; Brett, Dan J L; Russell, Andrea E; Lin, Wen-Feng; Hardacre, Christopher

    2016-05-25

    Direct alcohol fuel cells (DAFCs) mostly use low molecular weight alcohols such as methanol and ethanol as fuels. However, short-chain alcohol molecules have a relative high membrane crossover rate in DAFCs and a low energy density. Long chain alcohols such as butanol have a higher energy density, as well as a lower membrane crossover rate compared to methanol and ethanol. Although a significant number of studies have been dedicated to low molecular weight alcohols in DAFCs, very few studies are available for longer chain alcohols such as butanol. A significant development in the production of biobutanol and its proposed application as an alternative fuel to gasoline in the past decade makes butanol an interesting candidate fuel for fuel cells. Different butanol isomers were compared in this study on various Pt and PtSn bimetallic catalysts for their electro-oxidation activities in acidic media. Clear distinctive behaviors were observed for each of the different butanol isomers using cyclic voltammetry (CV), indicating a difference in activity and the mechanism of oxidation. The voltammograms of both n-butanol and iso-butanol showed similar characteristic features, indicating a similar reaction mechanism, whereas 2-butanol showed completely different features; for example, it did not show any indication of poisoning. Ter-butanol was found to be inactive for oxidation on Pt. In situ FTIR and CV analysis showed that OHads was essential for the oxidation of primary butanol isomers which only forms at high potentials on Pt. In order to enhance the water oxidation and produce OHads at lower potentials, Pt was modified by the oxophilic metal Sn and the bimetallic PtSn was studied for the oxidation of butanol isomers. A significant enhancement in the oxidation of the 1° butanol isomers was observed on addition of Sn to the Pt, resulting in an oxidation peak at a potential ∼520 mV lower than that found on pure Pt. The higher activity of PtSn was attributed to the

  17. Investigation of Amphibian Mortality Events in Wildlife Reveals an On-Going Ranavirus Epidemic in the North of the Netherlands.

    Science.gov (United States)

    Rijks, Jolianne M; Saucedo, Bernardo; Spitzen-van der Sluijs, Annemarieke; Wilkie, Gavin S; van Asten, Alphons J A M; van den Broek, Jan; Boonyarittichaikij, Roschong; Stege, Marisca; van der Sterren, Fleur; Martel, An; Pasmans, Frank; Hughes, Joseph; Gröne, Andrea; van Beurden, Steven J; Kik, Marja J L

    2016-01-01

    In the four years following the first detection of ranavirus (genus Ranavirus, family Iridoviridae) infection in Dutch wildlife in 2010, amphibian mortality events were investigated nationwide to detect, characterize and map ranaviruses in amphibians over time, and to establish the affected host species and the clinico-pathological presentation of the disease in these hosts. The ultimate goal was to obtain more insight into ranavirus disease emergence and ecological risk. In total 155 dead amphibians from 52 sites were submitted between 2011 and 2014, and examined using histopathology, immunohistochemistry, virus isolation and molecular genetic characterization. Ranavirus-associated amphibian mortality events occurred at 18 sites (35%), initially only in proximity of the 2010 index site. Specimens belonging to approximately half of the native amphibian species were infected, including the threatened Pelobates fuscus (spadefoot toad). Clustered massive outbreaks involving dead adult specimens and ranavirus genomic identity indicated that one common midwife toad virus (CMTV)-like ranavirus strain is emerging in provinces in the north of the Netherlands. Modelling based on the spatiotemporal pattern of spread showed a high probability that this emerging virus will continue to be detected at new sites (the discrete reproductive power of this outbreak is 0.35). Phylogenetically distinct CMTV-like ranaviruses were found in the south of the Netherlands more recently. In addition to showing that CMTV-like ranaviruses threaten wild amphibian populations not only in Spain but also in the Netherlands, the current spread and risk of establishment reiterate that understanding the underlying causes of CMTV-like ranavirus emergence requires international attention.

  18. Investigation of Amphibian Mortality Events in Wildlife Reveals an On-Going Ranavirus Epidemic in the North of the Netherlands.

    Directory of Open Access Journals (Sweden)

    Jolianne M Rijks

    Full Text Available In the four years following the first detection of ranavirus (genus Ranavirus, family Iridoviridae infection in Dutch wildlife in 2010, amphibian mortality events were investigated nationwide to detect, characterize and map ranaviruses in amphibians over time, and to establish the affected host species and the clinico-pathological presentation of the disease in these hosts. The ultimate goal was to obtain more insight into ranavirus disease emergence and ecological risk. In total 155 dead amphibians from 52 sites were submitted between 2011 and 2014, and examined using histopathology, immunohistochemistry, virus isolation and molecular genetic characterization. Ranavirus-associated amphibian mortality events occurred at 18 sites (35%, initially only in proximity of the 2010 index site. Specimens belonging to approximately half of the native amphibian species were infected, including the threatened Pelobates fuscus (spadefoot toad. Clustered massive outbreaks involving dead adult specimens and ranavirus genomic identity indicated that one common midwife toad virus (CMTV-like ranavirus strain is emerging in provinces in the north of the Netherlands. Modelling based on the spatiotemporal pattern of spread showed a high probability that this emerging virus will continue to be detected at new sites (the discrete reproductive power of this outbreak is 0.35. Phylogenetically distinct CMTV-like ranaviruses were found in the south of the Netherlands more recently. In addition to showing that CMTV-like ranaviruses threaten wild amphibian populations not only in Spain but also in the Netherlands, the current spread and risk of establishment reiterate that understanding the underlying causes of CMTV-like ranavirus emergence requires international attention.

  19. Nuclear fuel element

    Science.gov (United States)

    Zocher, Roy W.

    1991-01-01

    A nuclear fuel element and a method of manufacturing the element. The fuel element is comprised of a metal primary container and a fuel pellet which is located inside it and which is often fragmented. The primary container is subjected to elevated pressure and temperature to deform the container such that the container conforms to the fuel pellet, that is, such that the container is in substantial contact with the surface of the pellet. This conformance eliminates clearances which permit rubbing together of fuel pellet fragments and rubbing of fuel pellet fragments against the container, thus reducing the amount of dust inside the fuel container and the amount of dust which may escape in the event of container breach. Also, as a result of the inventive method, fuel pellet fragments tend to adhere to one another to form a coherent non-fragmented mass; this reduces the tendency of a fragment to pierce the container in the event of impact.

  20. Investigations of Aluminum-Doped Self-Healing Zircaloy Surfaces in Context of Accident-Tolerant Fuel Cladding Research

    Science.gov (United States)

    Carr, James; Vasudevamurthy, Gokul; Snead, Lance; Hinderliter, Brian; Massey, Caleb

    2016-06-01

    We present here some important results investigating aluminum as an effective surface dopant for increased oxidation resistance of zircaloy nuclear fuel cladding. At first, the transport behavior of aluminum into reactor grade zircaloy was studied using simple diffusion couples at temperatures greater than 770 K. The experiments revealed the formation of tens of microns thick graded Zr-Al layers. The activation energy of aluminum in zircaloy was found to be ~175 kJ/mol (~1.8 eV), indicating the high mobility of aluminum in zircaloy. Subsequently, aluminum sputter-coated zircaloy coupons were heat-treated to achieve surface doping and form compositionally graded layers. These coupons were then tested in steam environments at 1073 and 1273 K. The microstructure of the as-fabricated and steam-corroded specimens was compared to those of pure zircaloy control specimens. Analysis of data revealed that aluminum effectively competed with zircaloy for oxygen up until 1073 K blocking oxygen penetration, with no traces of large scale spalling, indicating mechanically stable interfaces and surfaces. At the highest steam test temperatures, aluminum was observed to segregate from the Zr-Al alloy under layers and migrate to the surface forming discrete clusters. Although this is perceived as an extremely desirable phenomenon, in the current experiments, oxygen was observed to penetrate into the zirconium-rich under layers, which could be attributed to formation of surface defects such as cracks in the surface alumina layers.

  1. Computational investigation of the flow field contribution to improve electricity generation in granular activated carbon-assisted microbial fuel cells

    Science.gov (United States)

    Zhao, Lei; Li, Jian; Battaglia, Francine; He, Zhen

    2016-11-01

    Microbial fuel cells (MFCs) offer an alternative approach to treat wastewater with less energy input and direct electricity generation. To optimize MFC anodic performance, adding granular activated carbon (GAC) has been proved to be an effective way, most likely due to the enlarged electrode surface for biomass attachment and improved mixing of the flow field. The impact of a flow field on the current enhancement within a porous anode medium (e.g., GAC) has not been well understood before, and thus is investigated in this study by using mathematical modeling of the multi-order Butler-Volmer equation with computational fluid dynamics (CFD) techniques. By comparing three different CFD cases (without GAC, with GAC as a nonreactive porous medium, and with GAC as a reactive porous medium), it is demonstrated that adding GAC contributes to a uniform flow field and a total current enhancement of 17%, a factor that cannot be neglected in MFC design. However, in an actual MFC operation, this percentage could be even higher because of the microbial competition and energy loss issues within a porous medium. The results of the present study are expected to help with formulating strategies to optimize MFC with a better flow pattern design.

  2. Experimental investigation of carbon monoxide poisoning effect on a PBI/H3PO4 high temperature polymer electrolyte membrane fuel cell

    DEFF Research Database (Denmark)

    Zhou, Fan; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2015-01-01

    of CO2 and water content in anode stream on CO poisoning of a HT-PEM fuel cell were investigated. Polarization curves and electrochemical impedance spectra were measured to quantify the performance loss caused by CO poisoning under different conditions. The experimental results suggest that higher anode...

  3. Experimental and analytical investigation on the emission and combustion characteristics of CI engine fueled with tamanu oil methyl esters

    OpenAIRE

    Perumal Navaneetha Krishnan; Durairaj Vasudevan

    2016-01-01

    The emission and combustion characteristics of a four stroke multi fuel single cylinder variable compression ratio engine fueled with tamanu oil methyl ester and its blends 10%, 20%, 40%, and 60% with diesel (on volume basis) are examined and compared with standard diesel. Biodiesel produced from tamanu oil by trans-esterification process has been used in this study. The experiment has been conducted at a constant engine speed of 1500 rpm with 50% load and ...

  4. Extending the scope of 'in silico experiments': Theoretical approaches for the investigation of reaction mechanisms, nucleation events and phase transitions

    Directory of Open Access Journals (Sweden)

    Dirk Zahn et al

    2007-01-01

    Full Text Available The investigation of the atomistic mechanisms of processes in complex systems constitutes a major challenge to both theory and experiment. While experimental studies offer a wide variety of insights at the macroscopic scale, the atomistic level of detail often remains elusive. On the other hand, molecular simulation approaches may easily achieve microscopic resolution and hence appear particularly suited for detailed mechanistic analyses. However, the computational effort is typically quite considerable and in many cases special simulation strategies are needed to make simulations possible. This review is dedicated to special approaches for tackling the time/length-scale problem inherent to molecular dynamics simulations. Employing these techniques opened a series of new perspectives. The latter are illustrated with the example of recent simulation studies of the atomistic mechanisms involved in complex processes like crystal nucleation, phase transitions and reactions in solution. Along this line, we discuss the reaction mechanisms for He insertion into C60 fullerenes, nucleation events and domain morphogenesis in pressure-induced phase transitions in solids and ion aggregation from solution.

  5. Some alternatives? Event-related potential investigation of literal and pragmatic interpretations of 'some' presented in isolation

    Directory of Open Access Journals (Sweden)

    Cecile Barbet

    2016-09-01

    Full Text Available In sentence verification tasks involving under-informative statements such as 'Some elephants are mammals', some adults appear more tolerant to pragmatic violations than others. The underlying causes of such inter-individual variability remain however essentially unknown. Here, we investigated inter-individual variation in adults deriving the scalar inference not all triggered by the quantifier 'some'. We first assessed the individual intolerance to pragmatic violations in adult participants presented with under-informative some-statements (e.g., Some infants are young. We then recorded event-related brain potentials in the same participants using an oddball paradigm where an ambiguous deviant word 'some' presented in isolation had to be taken either as a match (in its literal interpretation at least some or as a mismatch (in its pragmatic interpretation some but not all and where an unambiguous deviant target word 'all' was featured as control. Mean amplitude modulation of the classic P3b provided a measure of the ease with which participants considered 'some' and 'all' as deviants within each experimental block. We found that intolerance to pragmatic violations was associated with a reduction in the magnitude of the P3b effect elicited by the target 'some' when it was to be considered a literal match. However, we failed to replicate a straightforward literal interpretation facilitation effect in our experiment which offers a control for task demands. We propose that the derivation of scalar inferences also relies on general, but flexible, mismatch resolution processes.

  6. Emotional Incongruence of Facial Expression and Voice Tone Investigated with Event-Related Brain Potentials of Infants

    Directory of Open Access Journals (Sweden)

    Kota Arai

    2011-10-01

    Full Text Available Human emotions are perceived from multi-modal information including facial expression and voice tone. We aimed to investigate development of neural mechanism for cross-modal perception of emotions. We presented congruent and incongruent combinations of facial expression (happy and voice tone (happy or angry, and measured EEG to analyze event-related brain potentials for 8-10 month-old infants and adults. Ten repetitions of 10 trials were presented in random order for each participant. Half of them performed 20% congruent (happy face with happy voice and 80% incongruent (happy face with angry voice trials, and the others performed 80% congruent and 20% incongruent trials. We employed the oddball paradigm, but did not instruct participants to count a target. The odd-ball (infrequent stimulus increased the amplitude of P2 and delayed its latency for infants in comparison with the frequent stimulus. When the odd-ball stimulus was also emotionally incongruent, P2 amplitude was more increased and its latency was more delayed than for the odd-ball and emotionally congruent stimulus. However, we did not find difference of P2 amplitude or latency for adults between conditions. These results suggested that the 8–10 month-old infants already have a neural basis for detecting emotional incongruence of facial expression and voice tone.

  7. Investigation of bacterial effects of Asian dust events through comparison with seasonal variability in outdoor airborne bacterial community.

    Science.gov (United States)

    Park, Jonguk; Ichijo, Tomoaki; Nasu, Masao; Yamaguchi, Nobuyasu

    2016-10-20

    Atmospheric bacterial dispersion with aeolian dust has been reported to have a potential impact on public health and ecosystems. Asian dust is a major aeolian event that results in an estimated 4 million tons of Asian dust particles falling in Japan annually, 3,000-5,000 km away from their source regions. However, most studies have only investigated the effects of Asian dust during dust seasons. Therefore, in this study, outdoor bacterial abundance and community composition were determined by 16S rRNA quantitative PCR and amplicon sequencing, respectively, and compared on Asian and non-Asian dust days (2013-2015; 44 samples over four seasons). Seasonal variations in bacterial abundance of non-Asian dust days were not observed. Bacterial abundance of individual samples collected on non-Asian dust days changed dynamically relative to Asian dust days, with bacterial abundance occasionally reaching those of Asian dust days. The bacterial community composition on non-Asian dust days was rather stable seasonally, and did not differ from that on Asian dust days. These results indicate that bacteria in Asian dust does not immediately influence indigenous bacterial communities at the phylum/class level in distant downwind areas; accordingly, further studies of bacterial communities in downwind areas closer to the dust source are warranted.

  8. Construction of a Direct Water-Injected Two-Stroke Engine for Phased Direct Fuel Injection-High Pressure Charging Investigations

    Science.gov (United States)

    Somsel, James P.

    1998-01-01

    The development of a water injected Orbital Combustion Process (OCP) engine was conducted to assess the viability of using the powerplant for high altitude NASA aircraft and General Aviation (GA) applications. An OCP direct fuel injected, 1.2 liter, three cylinder, two-stroke engine has been enhanced to independently inject water directly into the combustion chamber. The engine currently demonstrates low brake specific fuel consumption capability and an excellent power to weight ratio. With direct water injection, significant improvements can be made to engine power, to knock limits/ignition advance timing, and to engine NO(x) emissions. The principal aim of the testing was to validate a cyclic model developed by the Systems Analysis Branch at NASA Ames Research Center. The work is a continuation of Ames' investigations into a Phased Direct Fuel Injection Engine with High Pressure Charging (PDFI-ITPC).

  9. Taguchi Method for Investigating the Performance Parameters and Exergy of a Diesel Engine Using Four Types of Diesel Fuels

    Directory of Open Access Journals (Sweden)

    Dara K. Khidir

    2016-05-01

    Full Text Available The effects of changes in engine operating parameters, i.e., engine speed, throttle and water temperature, for four types of diesel fuel (A, B, C and D of different specific gravities, as supplied from local market and refineries, were studied and simultaneously optimized. The experiment design was based on Taguchi’s “L' 16” orthogonal table, and the engine was put to test at different engine speeds, throttling opening percentages and water temperatures, using different fuels. The data were analyzed using S/N (signal to noise ratio for each factor. The obtained results show that the optimum operating conditions for minimum BSFC (brake specific fuel consumption are achieved when the engine speed is 2500 rpm, the throttle is placed at 75% of full throttling, the water temperature is 80 oC and the engine is using fuel type D. Also, results of S/N ratio reveal that the throttle has significant influence on brake thermal and exergic efficiencies. Water temperature is the second most effective factor and then comes the influence of engine speed. The least effective factor among the studied parameters for the types of fuel considered in this experiment is the fuel type.

  10. Experimental investigation on the morphology of soot aggregates from the burning of typical solid and liquid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Dongmei, E-mail: 20021567@163.com; Guo, Chenning [China Jiliang University, College of Quality and Safety Engineering (China); Shi, Long [RMIT University, Civil and Infrastructure Engineering Discipline, School of Engineering (Australia)

    2017-03-15

    Soot particles from the burning of typical fuels are one of the critical sources causing environmental problems and human disease. To understand the soot formation of these typical fuels, the size and morphology of soot aggregates produced from the burning of typical solid and liquid fuels, including diesel, kerosene, natural rubber (NR) latex foam, and wood crib, were studied by both extractive sampling and subsequent image analysis. The 2D and 3D fractal dimensions together with the diameter distribution of agglomerate and primary particles were analyzed for these four typical fuels. The average diameters of the primary particles were within 45–85 nm when sampling from different heights above the fire sources. Irregular sheet structures and flake-like masses were observed from the burning of NR latex foam and wood cribs. Superaggregates with a mean maximum length scale of over 100 μm were also found from the burning of all these four tested fuels. The fractal dimension of a single aggregate was 3 for all the tested fuels.

  11. Numerical investigation of interfacial mass transport resistance and two-phase flow in PEM fuel cell air channels

    Science.gov (United States)

    Koz, Mustafa

    Proton exchange membrane fuel cells (PEMFCs) are efficient and environmentally friendly electrochemical engines. The performance of a PEMFC is adversely affected by oxygen (O2) concentration loss from the air flow channel to the cathode catalyst layer (CL). Oxygen transport resistance at the gas diffusion layer (GDL) and air channel interface is a non-negligible component of the O2 concentration loss. Simplified PEMFC performance models in the available literature incorporate the O2 resistance at the GDL-channel interface as an input parameter. However, this parameter has been taken as a constant so far in the available literature and does not reflect variable PEMFC operating conditions and the effect of two-phase flow in the channels. This study numerically calculates the O2 transport resistance at the GDL-air channel interface and expresses this resistance through the non-dimensional Sherwood number (Sh). Local Sh is investigated in an air channel with multiple droplets and films inside. These water features are represented as solid obstructions and only air flow is simulated. Local variations of Sh in the flow direction are obtained as a function of superficial air velocity, water feature size, and uniform spacing between water features. These variations are expressed with mathematical expressions for the PEMFC performance models to utilize and save computational resources. The resulting mathematical correlations for Sh can be utilized in PEMFC performance models. These models can predict cell performance more accurately with the help of the results of this work. Moreover, PEMFC performance models do not need to use a look-up table since the results were expressed through correlations. Performance models can be kept simplified although their predictions will become more realistic. Since two-phase flow in channels is experienced mostly at lower temperatures, performance optimization at low temperatures can be done easier.

  12. Investigation of the Feasibility of Utilizing Gamma Emission Computed Tomography in Evaluating Fission Product Migration in Irradiated TRISO Fuel Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Jason M. Harp; Paul A. Demkowicz

    2014-10-01

    In the High Temperature Gas-Cooled Reactor (HTGR) the TRISO particle fuel serves as the primary fission product containment. However the large number of TRISO particles present in proposed HTGRs dictates that there will be a small fraction (~10-4 to 10-5) of as manufactured and in-pile particle failures that will lead to some fission product release. The matrix material surrounding the TRISO particles in fuel compacts and the structural graphite holding the TRISO particles in place can also serve as sinks for containing any released fission products. However data on the migration of solid fission products through these materials is lacking. One of the primary goals of the AGR-3/4 experiment is to study fission product migration from failed TRISO particles in prototypic HTGR components such as structural graphite and compact matrix material. In this work, the potential for a Gamma Emission Computed Tomography (GECT) technique to non-destructively examine the fission product distribution in AGR-3/4 components and other irradiation experiments is explored. Specifically, the feasibility of using the Idaho National Laboratory (INL) Hot Fuels Examination Facility (HFEF) Precision Gamma Scanner (PGS) system for this GECT application is considered. To test the feasibility, the response of the PGS system to idealized fission product distributions has been simulated using Monte Carlo radiation transport simulations. Previous work that applied similar techniques during the AGR-1 experiment will also be discussed as well as planned uses for the GECT technique during the post irradiation examination of the AGR-2 experiment. The GECT technique has also been applied to other irradiated nuclear fuel systems that were currently available in the HFEF hot cell including oxide fuel pins, metallic fuel pins, and monolithic plate fuel.

  13. P3b versus P3a: an event-related potential investigation of the glucose facilitation effect.

    Science.gov (United States)

    Riby, L M; Sünram-Lea, S I; Graham, C; Foster, J K; Cooper, T; Moodie, C; Gunn, V P

    2008-07-01

    The ingestion of a glucose containing drink has been shown to improve performance on a variety of cognitive tasks. There is debate, however, as to whether glucose especially benefits hippocampal memory functioning or whether it has a more global effect on attentional systems. The present study used event related potential methodology (ERPs) to investigate further glucose-mediated cognitive processes. Each participant acted as his/her own control in a repeated measures design, receiving one of two possible treatments (25 g glucose vs. placebo) in a counterbalanced order. After a two hour fasting period participants completed a visual three-stimulus oddball task. This paradigm involves an individual detecting an infrequent target stimulus randomly embedded in a train of repetitive background or standard stimuli. Detection of the target results in a large P3b ERP component (memory updating effect). The infrequent presentation of a novel and irrelevant stimulus, randomly interspersed with the target and standard stimuli, generates a P3a response (orientation of attention effect). These components were used as markers to establish whether the glucose enhancement effect was restricted to the neuro-cognitive processes related to memory. Consistent with behavioural work, glucose moderated the magnitude and latency of the P3b ERP component. However, glucose also interacted with attentional systems (P3a and an earlier P2), although this effect was non-significant. This work converges with recent fMRI findings indicating the sensitivity of the medial-temporal lobes and the pre-frontal cortex to glucose administration.

  14. The Investigation of Mobbing Events Taking Place at Higher Education Institutions in Turkey Considering the Reflections on Media

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    Çubukçu Zühal

    2015-08-01

    Full Text Available The business-life related competition established in modern communities has also brought about some other problems. The attacks and intimidation attempts have introduced the term of “mobbing” which is defined as regular and continuous psychological violence faced by people always trying to produce and win from those who they work with. The term of “mobbing” has recently become a popular academic issue which has been sophisticatedly handled in relevant literature. Mobbing is defined as the act of continuous and systematic intimidation purposefully performed by either some employees or employers on some employees through emotional violence. As mobbing is considered to be significant for both corporate and employee, the starting point of this study was to investigate how mobbing acts are reflected on newspapers as they are mass communication means. One of the most important means of media is print media. Print media is the first means of media when mentioned about media. Newspapers are means through which people are always kept up to date about the latest news in civilized societies. With this regard, the most basic purpose of this study is to investigate the news about the mobbing events experienced in higher education system under the light of national policy documents and reports. The study was carried out based on a qualitative approach. The news released in print media was chosen purposefully as print media means report news in a detailed way, have an evidential value and can be read again on demand. The research group in this study consists of the mobbing news released on Hurriyet, Sabah and Zaman which are newspapers published in Turkey between the years of 2009-2013. These newspapers were purposefully chosen based on criterion sampling method. The most basic understanding underlying this sampling method is to study on all cases which meet the standards set prior to the start of the study. The newspapers mentioned above were chosen

  15. Preliminary investigation of polynuclear aromatic hydrocarbon emissions from a diesel engine operating on vegetable oil-based alternative fuels

    Energy Technology Data Exchange (ETDEWEB)

    Mills, G.A.; Howard, A.G.

    1983-09-01

    Polynuclear aromatic hydrocarbon (PAH) exhaust emissions from a diesel engine operating on unmodified (sunflower, rapeseed, soyabean) and modified (ethyl-ester sunflower) vegetable oil were compared with emissions resulting from the combustion of diesel gas oil. Three engine load/speed conditions were assessed for each fuel and emission levels for 20 PAH compounds are presented for each test. PAH emission profiles arising from the combustion of unmodified oils were similar, with the total PAH exhaust concentrations generally being lower than the levels obtained using diesel fuel. Increasing engine load was found to increase greatly the production of carcinogenic PAH species in the exhaust from combusted unmodified vegetable oils. The formation of alkyl-substituted PAH, common in diesel exhaust emissions, was very limited using these fuels. Results obtained from operation of the engine on the ethyl-ester of sunflower oil indicated PAH emissions in between those obtained using diesel oil and the unmodified vegetable oils. 18 references.

  16. A preliminary investigation of polynuclear aromatic hydrocarbon emissions from a diesel engine operating on vegetable oil-based alternative fuels

    Energy Technology Data Exchange (ETDEWEB)

    Mills, G.A.; Howard, A.G.

    1983-09-01

    Polynuclear aromatic hydrocarbon (PAH) exhaust emissions from a diesel engine operating on unmodified (sunflower, rapeseed, soyabean) and modified (ethyl-ester sunflower) vegetable oil were compared with emissions resulting from the combustion of diesel gas oil. Three engine load/speed conditions were assessed for each fuel and emission levels for 20 PAH compounds are presented for each test. PAH emission profiles arising from the combustion of unmodified oils were similar, with the total PAH exhaust concentrations generally being lower than the levels obtained using diesel fuel. Increasing engine load was found to increase greatly the production of carcinogenic PAH species in the exhaust from combusted unmodified vegetable oils. The formation of alkyl-substituted PAH, common in diesel exhaust emissions, was very limited using these fuels. Results obtained from operation of the engine on the ethyl-ester of sunflower oil indicated PAH emissions in between those obtained using diesel oil and the unmodified vegetable oils

  17. Experimental investigation of syngas flame stability using a multi-tube fuel injector in a high pressure combustor

    Science.gov (United States)

    Maldonado, Sergio Elzar

    Over 92% of the coal consumed by power plants is used to generate electricity in the United States (U.S.). The U.S. has the world's largest recoverable reserves of coal, it is estimated that reserves of coal will last more than 200 years based in current production and demand levels. Integrated Gasification Combined Cycle (IGCC) power plants aim to reduce the amount of pollutants by gasifying coal and producing synthesis gas. Synthesis gas, also known as syngas, is a product of coal gasification and can be used in gas turbines for energy production. Syngas is primarily a mixture of hydrogen and carbon monoxide and is produced by gasifying a solid fuel feedstock such as coal or biomass. The objective of the thesis is to create a flame stability map by performing various experiments using high-content hydrogen fuels with varying compositions of hydrogen representing different coal feedstocks. The experiments shown in this thesis were performed using the High-Pressure Combustion facility in the Center for Space Exploration Technology Research (CSETR) at the University of Texas at El Paso (UTEP). The combustor was fitted with a novel Multi-Tube fuel Injector (MTI) designed to improve flame stability. This thesis presents the results of testing of syngas fuels with compositions of 20, 30, and 40% hydrogen concentrations in mixtures with carbon monoxide. Tests were completed for lean conditions ranging from equivalence ratios between 0.6 and 0.9. The experimental results showed that at an equivalence ratio of 0.6, a stable flame was not achieved for any of the fuel mixtures tested. It was also observed that the stability region of the syngas flame increased as equivalence ratio and the hydrogen concentration in syngas fuel increases with the 40% hydrogen-carbon monoxide mixture demonstrating the greatest stability region. Design improvements to the MTI are also discussed as part of the future work on this topic.

  18. The Investigation and Development of Low Cost Hardware Components for Proton-Exchange Membrane Fuel Cells - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    George A. Marchetti

    1999-12-15

    Proton exchange membrane (PEM) fuel cell components, which would have a low-cost structure in mass production, were fabricated and tested. A fuel cell electrode structure, comprising a thin layer of graphite (50 microns) and a front-loaded platinum catalyst layer (600 angstroms), was shown to produce significant power densities. In addition, a PEM bipolar plate, comprising flexible graphite, carbon cloth flow-fields and an integrated polymer gasket, was fabricated. Power densities of a two-cell unit using this inexpensive bipolar plate architecture were shown to be comparable to state-of-the-art bipolar plates.

  19. Investigation of black and brown carbon multiple-wavelength-dependent light absorption from biomass and fossil fuel combustion source emissions

    Science.gov (United States)

    Michael R. Olson; Mercedes Victoria Garcia; Michael A. Robinson; Paul Van Rooy; Mark A. Dietenberger; Michael Bergin; James Jay Schauer

    2015-01-01

    Quantification of the black carbon (BC) and brown carbon (BrC) components of source emissions is critical to understanding the impact combustion aerosols have on atmospheric light absorption. Multiple-wavelength absorption was measured from fuels including wood, agricultural biomass, coals, plant matter, and petroleum distillates in controlled combustion settings....

  20. Investigation into the effect of different fuels on ignition delay of M-type diesel combustion process

    Directory of Open Access Journals (Sweden)

    Bibić Dževad

    2008-01-01

    Full Text Available An ignition delay is a very complex process which depends on a great number of parameters. In practice, definition of the ignition delay is based on the use of correlation expressions. However, the correlation expressions have very often limited application field. This paper presents a new correlation which has been developed during the research project on the direct injection M-type diesel engine using both the diesel and biodiesel fuel, as well as different values of a static injection timing. A dynamic start of injection, as well as the ignition delay, is defined in two ways. The first approach is based on measurement of a needle lift, while the second is based on measurement of a fuel pressure before the injector. The latter approach requires calculation of pressure signals delay through the fuel injection system and the variation of a static advance injection angle changing. The start of a combustion and the end of the ignition delay is defined on the basis of measurements of an in-cylinder pressure and its point of separation from a skip-fire pressure trace. The developed correlation gives better prediction of the ignition delay definition for the M-type direct injection diesel engine in the case of diesel and biodiesel fuel use when compared with the classic expression by the other authors available in the literature.

  1. Experimental investigation and performance evaluation of DI diesel engine fueled by waste oil-diesel mixture in emulsion with water

    Directory of Open Access Journals (Sweden)

    Nanthagopal Kasianantham

    2009-01-01

    Full Text Available Exploitation of the natural reserves of petroleum products has put a tremendous onus on the automotive industry. Increasing pollution levels and the depletion of the petroleum reserves have lead to the search for alternate fuel sources for internal combustion engines. Usage of vegetable oils poses some challenges like poor spray penetration, valve sticking and clogging of injector nozzles. Most of these problems may be solved by partial substitution of diesel with vegetable oil. In this work, the performance and emission characteristics of a direct injection diesel engine fueled by waste cooking oil-diesel emulsion with different water contents are evaluated. The use of waste cooking oil-diesel emulsion lowers the peak temperature, which reduces the formation of NOx. Moreover the phenomenon of micro explosion that results during the combustion of an emulsified fuel finely atomizes the fuel droplets and thus enhances combustion. Experiments show that CO concentration is reduced as the water content is increased and it is seen that 20% water content gives optimum results. Also, there is a significant reduction in NOx emissions.

  2. Cool? Young people investigate living in cold housing and fuel poverty. A mixed methods action research study

    Directory of Open Access Journals (Sweden)

    Kimberley C. O'Sullivan

    2017-12-01

    Conclusion: The integrated results confirm that cold housing and risk of fuel poverty are important problems for young people in New Zealand. Results contribute to the evidence-base for policy targeting of schemes such as the Government-sponsored retrofitting of insulation to households with dependent children.

  3. An investigation of crown fuel bulk density effects on the dynamics of crown fire initiation in shrublands

    Science.gov (United States)

    Watcharapong Tachajapong; Jesse Lozano; Shankar Mahalingam; Xiangyang Zhou; David R. Weise

    2008-01-01

    Crown fire initiation is studied by using a simple experimental and detailed physical modeling based on Large Eddy Simulation (LES). Experiments conducted thus far reveal that crown fuel ignition via surface fire occurs when the crown base is within the continuous flame region and does not occur when the crown base is located in the hot plume gas region of the surface...

  4. Disagreements between central clinical events committee and site investigator assessments of myocardial infarction endpoints in an international clinical trial: review of the PURSUIT study

    Directory of Open Access Journals (Sweden)

    Lee Kerry L

    2001-07-01

    Full Text Available Abstract Background Limited information has been published regarding how specific processes for event adjudication can affect event rates in trials. We reviewed nonfatal myocardial infarctions (MIs reported by site investigators in the international Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin (Eptifibatide Therapy (PURSUIT trial and those adjudicated by a central clinical events committee (CEC to determine the reasons for differences in event rates. Methods The PURSUIT trial randomised 10,948 patients with acute coronary syndromes to receive eptifibatide or placebo. The primary end-point was death or post-enrolment MI at 30 days as assessed by the CEC; this end-point was also constructed using site-reported events. The CEC identified suspected MIs by systematic review of clinical, cardiac enzyme, and electrocardiographic data. Results The CEC identified 5005 (46% suspected events, of which 1415 (28% were adjudicated as MI. The site investigator and CEC assessments of whether a MI had occurred disagreed in 983 (20% of the 5005 patients with suspected MI, mostly reflecting site misclassification of post-enrolment MIs (as enrolment MIs or underreported periprocedural MIs. Patients for whom the CEC and site investigator agreed that no end-point MI had occurred had the lowest mortality at 30 days and between 30 days and 6 months, and those with agreement that a MI had occurred had the highest mortality. Conclusion CEC adjudication provides a standard, systematic, independent, and unbiased assessment of end-points, particularly for trials that span geographic regions and clinical practice settings. Understanding the review process and reasons for disagreement between CEC and site investigator assessments of MI is important to design future trials and interpret event rates between trials.

  5. Microfluidic fuel cell systems

    Science.gov (United States)

    Ho, Bernard; Kjeang, Erik

    2011-06-01

    A microfluidic fuel cell is a microfabricated device that produces electrical power through electrochemical reactions involving a fuel and an oxidant. Microfluidic fuel cell systems exploit co-laminar flow on the microscale to separate the fuel and oxidant species, in contrast to conventional fuel cells employing an ion exchange membrane for this function. Since 2002 when the first microfluidic fuel cell was invented, many different fuels, oxidants, and architectures have been investigated conceptually and experimentally. In this mini-review article, recent advancements in the field of microfluidic fuel cell systems are documented, with particular emphasis on design, operation, and performance. The present microfluidic fuel cell systems are categorized by the fluidic phases of the fuel and oxidant streams, featuring gaseous/gaseous, liquid/gaseous, and liquid/liquid systems. The typical cell configurations and recent contributions in each category are analyzed. Key research challenges and opportunities are highlighted and recommendations for further work are provided.

  6. Experimental investigation of the effects of diesel-like fuel obtained from waste lubrication oil on engine performance and exhaust emission

    Energy Technology Data Exchange (ETDEWEB)

    Arpa, Orhan [Dicle University, Mechanical Engineering Department, Diyarbakir (Turkey); Yumrutas, Recep [University of Gaziantep, Mechanical Engineering Department, Gaziantep (Turkey); Argunhan, Zeki [University of Batman, Mechanical Engineering Department, Batman (Turkey)

    2010-10-15

    In this study, effects of diesel-like fuel (DLF) on engine performance and exhaust emission are investigated experimentally. The DLF is produced from waste engine lubrication oil purified from dust, heavy carbon soot, metal particles, gum-type materials and other impurities. A fuel production system mainly consisting of a waste oil storage tank, filters, a reactor, oil pump, a product storage tank, thermostats and control panel is designed and manufactured. The DLF is produced by using the system and applying pyrolitic distillation method. Characteristics, performance and exhaust emissions tests of the produced DLF are carried out at the end of the production. The characteristic tests such as density, viscosity, flash point, heating value, sulfur content and distillation of the DLF sample are performed utilizing test equipments presented in motor laboratory of Mechanical Engineering Department, University of Gaziantep, Turkey. Performance and exhaust emission tests for the DLF are performed using diesel test engine. It is observed from the test results that about 60 cc out of each 100 cc of the waste oil are converted into the DLF. Characteristics and distillation temperatures of the DLF are close to those values of a typical diesel fuel sample. It is observed that the produced DLF can be used in diesel engines without any problem in terms of engine performance. The DLF increases torque, brake mean effective pressure, brake thermal efficiency and decreases brake specific fuel consumption of the engine for full power of operation. (author)

  7. Using temporally aligned event-related potentials for the investigation of attention shifts prior to and during saccades.

    Science.gov (United States)

    Huber-Huber, Christoph; Ditye, Thomas; Marchante Fernández, María; Ansorge, Ulrich

    2016-11-01

    According to the pre-motor theory of attention, attention is shifted to a saccade's landing position before the saccade is executed. Such pre-saccadic attention shifts are usually studied in psychophysical dual-task conditions, with a target-discrimination task before saccade onset. Here, we present a novel approach to investigate pre-saccadic attention shifts with the help of event-related potentials (ERPs). Participants executed one or two saccades to color-defined targets while ERPs and eye-movements were recorded. In single-target blocks participants executed a single saccade. In two-targets blocks participants made either a single saccade to one of the targets, or two successive saccades to both targets. Importantly, in two-targets blocks, targets could appear on the same or on opposite sides of the vertical midline. This allowed us to study contra-to-ipsilateral ERP differences (such as the N2pc or PCN) that reflect attention shifts to the targets, prior to saccade onset and during saccades. If pre-saccadic attention shifts to saccade target locations are necessary for saccade execution and if searched-for saccade targets capture attention, there should be enhanced attentional competition (1) between two targets compared to single targets; (2) between two opposite-sides targets compared to two same-side targets; and (3) in two saccades rather than one saccade conditions: More attentional competition was expected to delay saccade latency and to weaken pre-saccadic laterality effects in ERPs. Hypotheses were tested by means of temporally aligned ERPs that were simultaneously time-locked to stimulus onsets, saccade onsets, and saccade offsets. Predictions (1) and (2) were partly and fully confirmed, respectively, but no evidence was found for (3). We explain the implications of our results for the role of attention during saccade preparation, and we point out how temporally aligned ERPs compare to ICA-based electroencephalogram (EEG) artifact correction

  8. Investigation of the Thermal Performance of a Vertical Two-Phase Closed Thermosyphon as a Passive Cooling System for a Nuclear Reactor Spent Fuel Storage Pool

    Directory of Open Access Journals (Sweden)

    Mukhsinun Hadi Kusuma

    2017-04-01

    Full Text Available The decay heat that is produced by nuclear reactor spent fuel must be cooled in a spent fuel storage pool. A wickless heat pipe or a vertical two-phase closed thermosyphon (TPCT is used to remove this decay heat. The objective of this research is to investigate the thermal performance of a prototype model for a large-scale vertical TPCT as a passive cooling system for a nuclear research reactor spent fuel storage pool. An experimental investigation and numerical simulation using RELAP5/MOD 3.2 were used to investigate the TPCT thermal performance. The effects of the initial pressure, filling ratio, and heat load were analyzed. Demineralized water was used as the TPCT working fluid. The cooled water was circulated in the water jacket as a cooling system. The experimental results show that the best thermal performance was obtained at a thermal resistance of 0.22°C/W, the lowest initial pressure, a filling ratio of 60%, and a high evaporator heat load. The simulation model that was experimentally validated showed a pattern and trend line similar to those of the experiment and can be used to predict the heat transfer phenomena of TPCT with varying inputs.

  9. Investigation of the thermal performance of a vertical two-phase closed thermosyphon as a passive cooling system for a nuclear reactor spent fuel storage pool

    Energy Technology Data Exchange (ETDEWEB)

    Kusuma, Mukhsinun Hadi; Putra, Nandy; Imawan, Ficky Augusta [Heat Transfer Laboratory, Department of Mechanical Engineering Universitas Indonesia, Kampus (Indonesia); Antariksawan, Anhar Riza [Centre for Nuclear Reactor Safety and Technology, National Nuclear Energy Agency of Indonesia (BATAN), Kawasan Puspiptek Serpong (Indonesia)

    2017-04-15

    The decay heat that is produced by nuclear reactor spent fuel must be cooled in a spent fuel storage pool. A wickless heat pipe or a vertical two-phase closed thermosyphon (TPCT) is used to remove this decay heat. The objective of this research is to investigate the thermal performance of a prototype model for a large-scale vertical TPCT as a passive cooling system for a nuclear research reactor spent fuel storage pool. An experimental investigation and numerical simulation using RELAP5/MOD 3.2 were used to investigate the TPCT thermal performance. The effects of the initial pressure, filling ratio, and heat load were analyzed. Demineralized water was used as the TPCT working fluid. The cooled water was circulated in the water jacket as a cooling system. The experimental results show that the best thermal performance was obtained at a thermal resistance of 0.22°C/W, the lowest initial pressure, a filling ratio of 60%, and a high evaporator heat load. The simulation model that was experimentally validated showed a pattern and trend line similar to those of the experiment and can be used to predict the heat transfer phenomena of TPCT with varying inputs.

  10. The DO-climate events are probably noise induced: statistical investigation of the claimed 1470 years cycle

    Directory of Open Access Journals (Sweden)

    P. D. Ditlevsen

    2007-01-01

    Full Text Available The significance of the apparent 1470 years cycle in the recurrence of the Dansgaard-Oeschger (DO events, observed in the Greenland ice cores, is debated. Here we present statistical significance tests of this periodicity. The detection of a periodicity relies strongly on the accuracy of the dating of the DO events. Here we use both the new NGRIP GICC05 time scale based on multi-parameter annual layer counting and the GISP2 time scale where the periodicity is most pronounced. For the NGRIP dating the recurrence times are indistinguishable from a random occurrence. This is also the case for the GISP2 dating, except in the case where the DO9 event is omitted from the record.

  11. A replica exchange transition interface sampling method with multiple interface sets for investigating networks of rare events

    NARCIS (Netherlands)

    Swenson, D.W.H.; Bolhuis, P.G.

    2014-01-01

    The multiple state transition interface sampling (TIS) framework in principle allows the simulation of a large network of complex rare event transitions, but in practice suffers from convergence problems. To improve convergence, we combine multiple state TIS [J. Rogal and P. G. Bolhuis, J. Chem.

  12. Fuel Exhaling Fuel Cell.

    Science.gov (United States)

    Manzoor Bhat, Zahid; Thimmappa, Ravikumar; Devendrachari, Mruthyunjayachari Chattanahalli; Kottaichamy, Alagar Raja; Shafi, Shahid Pottachola; Varhade, Swapnil; Gautam, Manu; Thotiyl, Musthafa Ottakam

    2018-01-18

    State-of-the-art proton exchange membrane fuel cells (PEMFCs) anodically inhale H 2 fuel and cathodically expel water molecules. We show an unprecedented fuel cell concept exhibiting cathodic fuel exhalation capability of anodically inhaled fuel, driven by the neutralization energy on decoupling the direct acid-base chemistry. The fuel exhaling fuel cell delivered a peak power density of 70 mW/cm 2 at a peak current density of 160 mA/cm 2 with a cathodic H 2 output of ∼80 mL in 1 h. We illustrate that the energy benefits from the same fuel stream can at least be doubled by directing it through proposed neutralization electrochemical cell prior to PEMFC in a tandem configuration.

  13. Investigating the engine vibration in MF285 tractor effected by different blends of biodiesel fuel using statistical methods and ANFIS

    OpenAIRE

    A Safrangian; L Naderloo; H Javadikia; M Mostafaei; S. S Mohtasebi

    2017-01-01

    Introduction Vibrations include a wide range of engineering sciences and discuss from different aspects. One of the aspects is related to various types of engines vibrations, which are often used as power sources in agriculture. The created vibrations can cause lack of comfort and reduce effective work and have bad influence on the health and safety. One of the important parameters of the diesel engine that has the ability to create vibration and knocking is the type of fuel. In this stud...

  14. Investigation on Aromaticity Index and Double-Bond Equivalent of Aromatic Compounds and Ionic Liquids for Fuel Desulphurization

    Directory of Open Access Journals (Sweden)

    Syamsul B. Abdullah

    2013-01-01

    Full Text Available Aromaticity index (AI and double-bond equivalent (DBE were studied to seek a simpler approach in identifying suitable ionic liquids for the desulphurization process. Manifestation of interaction mechanism by COSMO-RS and Raman spectroscopy is discussed. The findings demonstrate that AI and DBE calculations can be used to analyze and arrogate potential combination of cation and anion for fuel desulphurization purposes.

  15. The main directions in technology investigation of soid oxide fuel cell in Russian Federal Research Center Institute of Physics & Power Engineering (IPPE)

    Energy Technology Data Exchange (ETDEWEB)

    Ievleva, J.I.; Kolesnikov, V.P.; Mezhertisky, G.S. [and others

    1996-04-01

    The main direction of science investigations for creation of efficient solid oxide fuel cells (SOFC) in IPPE are considered in this work. The development program of planar SOFC with thin-film electrolyte is shown. General design schemes of experimental SOFC units are presented. The flow design schemes of processes for initial materials and electrodes fabrication are shown. The results of investigations for creation thin-film solid oxide electrolyte at porous cathode by magnetron sputtering from complex metal target in oxidative environment are presented.

  16. Investigation of strut-ramp injector in a Scramjet combustor: Effect of strut geometry, fuel and jet diameter on mixing characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Soni, Rahul Kumar; De, Ashoke De [Indian Institute of Technology Kanpur, Kanpur (India)

    2017-03-15

    The strut-based injector has been found to be one of the most promising injector designs for a supersonic combustor, offering enhanced mixing of fuel and air. The mixing and flow field characteristics of the straight (SS) and Tapered strut (TS), with fixed ramp angle and height at free stream Mach number 2 in conjunction with fuel injection at Mach 2.3 have been investigated numerically and reported. In the present investigation, hydrogen (H{sub 2}) and ethylene (C{sub 2}H{sub 4}) are injected in oncoming supersonic flow from the back of the strut, where jet to free stream momentum ratio is maintained at 0.79 and 0.69 for H2 and C{sub 2}H{sub 4}, respectively. The predicted wall static pressure and species mole fractions at various downstream locations are compared with the experimental data for TS case with 0.6 mm jet diameter and found to be in good agreement. Further, the effect of jet diameter and strut geometry on the near field mixing in strut ramp configuration is discussed for both the fuels. The numerical results are assessed based on various parameters for the performance evaluation of different strut ramp configurations. The SS configuration for both the injectant has been found to be an optimum candidate; also it is observed that for higher jet diameter larger combustor length is required to achieve satisfactory near field mixing.

  17. Preliminary investigation of the combustion of a 50 percent pentaborane - 50 percent JP-4 fuel blend in a turbojet combustor at simulated altitude conditions

    Science.gov (United States)

    Branstetter, J Robert; Kaufman, Warner B; Gibbs, James B

    1957-01-01

    A preliminary investigation was conducted to determine the combustion characteristics of a fuel composed of 50 percent pentaborane and 50 percent JP-4 (MIL-F-5624A) by weight in a turbojet combustor. A combustor designed to fit the housing of a J33-A-23 turbojet engine was selected for convenience. The fuel was evaluated at two engine conditions simulating altitudes of 40,000 and 57,000 feet, an engine speed of 85 percent of rated rpm, and a flight Mach number of 0.6. The pentaborane blend was initially evaluated in combustors developed for pure pentaborane and diborane reported in NACA RM E53B18 and RM E52L15. The performance of the blend was unsatisfactory in these combustors. A new combustor was then developed which provided combustor efficiencies measured from 91 to 101 percent as compared with efficiencies of 92 to 94 percent previously obtained for pentaborane at comparable conditions. Additional refinements of design details are needed to obtain lower oxide deposits and a more uniform outlet temperature profile; however, the combustor is believed to incorporate some of the design principles required to obtain satisfactory over-all performance with the fuel blend investigated.

  18. Investigations of relative sooting tendencies of different fuels in diffusion flames up to 10 bar; Untersuchungen zur relativen Russneigung verschiedener Kraftstoffe in Diffusionsflammen im Druckbereich bis 10 bar

    Energy Technology Data Exchange (ETDEWEB)

    Eberius, H.; Jander, H.

    1999-07-01

    The authors investigated the influence of the chemical structure of different fuels on soot formation in an engine. Soot-forming laminar diffusion flames were investigated in a high-pressure burner at pressures up to 10 bar with methane, i-octane and benzene as fuels. It was found that the relative sooting tendency of the fuels is strongly influenced by pressure. The differences in the relative sooting tendency can be measured qualitatively and to a large extent also quantitatively for defined and optimized flames. [German] Die Russbildung in Flammen, z.B. bei Flugtriebwerken haengt von einer Vielzahl von Parametern ab, wie Turbulenz, Temperaturfeld, Treibstoff und Einduesung des fluessigen Brennstoffs. Vor diesem Hintergrund stellt sich die Frage, wie weit einzelne Treibstoffkomponenten, allein aufgrund ihrer chemischen Struktur, die Russbildung beeinflussen. Zu dieser Fragestellung werden in einem Hochdruckbrenner russende laminare Diffusionsflammen im Druckbereich bis 10 bar untersucht mit Methan, i-Oktan und Benzol als Brennstoff. Als Ergebnis zeigt sich insbesondere ein grosser Einfluss des Druckes auf die relative Russneigung der Brennstoffe. Die Unterschiede der relativen Russneigung lassen sich fuer festgelegte und optimierte Flammen qualitativ und weitgehend auch quantitativ erfassen. (orig.)

  19. Report of an investigation into deterioration of the Plutonium Fuel Form Fabrication Facility (PuFF) at the DOE Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

    This investigations of the Savannah River Site's Plutonium Fuel Form fabrication facility located in Building 235-F was initiated in April 1991. The purpose of the investigation was to determine whether, as has been alleged, operation of the facility's argon inert gas system was terminated with the knowledge that continued inoperability of the argon system would cause accelerated corrosion damage to the equipment in the plutonium 238 processing cells. The investigation quickly established that the decision to discontinue operation of the argon system, by not repairing it, was merely one of the measures, and not the most important one, which led to the current deteriorated state of the facility. As a result, the scope of the investigation was broadened to more identify and assess those factors which contributed to the facility's current condition. This document discusses the backgrounds, results, and recommendations of this investigation.

  20. Investigating the Supersymmetric Explanation of Anomalous CDF lepton(s) photon(s) Missing-$E_T$ Events

    CERN Document Server

    Allanach, Benjamin C; Sridhar, K

    2002-01-01

    The recent excess over the Standard Model prediction in the \\mu \\gamma missing-E_T channel reported by CDF can be well-explained by resonant smuon production with a single dominant R-parity violating coupling \\lambda'_{211}, in the context of models where the gravitino is the lightest supersymmetric particle. The slepton decays to the lightest neutralino and a muon followed by neutralino decaying to a gravitino and photon. The kinematical distributions are fitted well by our hypothesis and we use them to constrain the available parameter space. The model also provides an explanation for the ee\\gamma\\gamma missing-E_T event observed in Run I of the Tevatron by the CDF experiment. Our model predicts an excess of between 5 and 35 events in a \\gamma missing-E_T channel at Run I. We provide predictions for signatures expected by the model at Run II.

  1. Experimental Investigation of Single-Event Transient Waveforms Depending on Transistor Spacing and Charge Sharing in 65-nm CMOS

    Science.gov (United States)

    Mitrović, Mladen; Hofbauer, Michael; Goll, Bernhard; Schneider-Hornstein, Kerstin; Swoboda, Robert; Steindl, Bernhard; Voss, Kay-Obbe; Zimmermann, Horst

    2017-08-01

    Single-event cross sections of four inverter chains, with uniform inverter spacing ranging from 120 nm to 4 μm, were experimentally measured and compared. These inverter chains were irradiated using a focused ion beam. Full analog waveforms of responses were sensed using on-chip wide-bandwidth analog multiplexers. Cross sections are examined with respect to pulse heights and pulse widths, for direct-hit waveforms as well as for waveforms propagated through the chain. The influence of ion hit position and charge sharing effects on the initial shape and propagation of the single-event transients (SETs) was analyzed. We have observed a considerable reduction of cross section for tightly spaced inverters, for both direct hits and propagated SETs.

  2. Investigating the Capability to Extract Impulse Response Functions From Ambient Seismic Noise Using a Mine Collapse Event

    Science.gov (United States)

    Kwak, Sangmin; Song, Seok Goo; Kim, Geunyoung; Cho, Chang Soo; Shin, Jin Soo

    2017-10-01

    Using recordings of a mine collapse event (Mw 4.2) in South Korea in January 2015, we demonstrated that the phase and amplitude information of impulse response functions (IRFs) can be effectively retrieved using seismic interferometry. This event is equivalent to a single downward force at shallow depth. Using quantitative metrics, we compared three different seismic interferometry techniques—deconvolution, coherency, and cross correlation—to extract the IRFs between two distant stations with ambient seismic noise data. The azimuthal dependency of the source distribution of the ambient noise was also evaluated. We found that deconvolution is the best method for extracting IRFs from ambient seismic noise within the period band of 2-10 s. The coherency method is also effective if appropriate spectral normalization or whitening schemes are applied during the data processing.

  3. Experimental investigation of the oxy-fuel combustion of hard coal in a circulating fluidized-bed combustion; Experimentelle Untersuchung der Oxy-Fuel-Verbrennung von Steinkohle in einer zirkulierenden Wirbelschichtfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Hofbauer, Gerrit Arne

    2017-03-16

    The United Nations Framework Convention on Climate Change (UNFCCC) in 1992 first illustrated the social, economic and politic focus being placed on combating climate change caused by anthropogenic greenhouse gases. From there onwards research and development efforts have particularly centred on the reduction of CO{sub 2} emissions in the production of electrical power through the use of carbonaceous fossil fuels. The long-term goal is a conversion to sustainable and CO{sub 2} free means of producing power, utilizing in the main part renewable forms of energy such as solar, wind and hydro power. Currently, such renewable ways of creating electricity only represent a small percentage of global energy production. The technological and economic hurdles that are associated with a substantial increase of renewable energy production have greatly slowed their increased implementation. However, the goal of keeping the atmospheric CO{sub 2} concentration below 450 ppm requires a significantly faster reduction in the amount of greenhouse gas emissions. Therefore, considerations are being given to bridge technologies which would be able to capture and store the CO{sub 2} emissions from fossil fired power plants. These technologies are referred to as CCS (carbon capture and storage). Oxy-fuel combustion, combustion with pure oxygen instead of air, is one of those technologies and forms the focus of investigation of this work. The Institute of Combustion and Power Plant Technology in Stuttgart, Germany, have researched this matter, carrying out combustion experiments in its 150 kW{sub th} circulating fluidized bed pilot facility. The experiments were aimed at investigating the influence of excess oxygen, combustion temperature and inlet oxygen concentration on the combustion process and comparing air to oxy-fuel combustion. These results were compared to the results of fundamental investigations and combustion experiments carried out by other research groups. The relationship

  4. Investigating the impact of Lake Agassiz drainage routes on the 8.2 ka cold event with climate modeling

    OpenAIRE

    Y.-X. Li; H. Renssen; A. P. Wiersma; T. E. Törnqvist

    2009-01-01

    The 8.2 ka event is the most prominent abrupt climate change in the Holocene and is widely believed to result from catastrophic drainage of proglacial lakes Agassiz and Ojibway (LAO) that routed through the Hudson Bay and the Labrador Sea into the North Atlantic Ocean, and perturbed Atlantic meridional overturning circulation (MOC). One key assumption of this triggering mechanism is that the LAO freshwater drainage was spread over the Labrador Sea. Recent data, however, show no evidence of lo...

  5. Experimental and analytical investigation on the emission and combustion characteristics of CI engine fueled with tamanu oil methyl esters

    Directory of Open Access Journals (Sweden)

    Perumal Navaneetha Krishnan

    2016-01-01

    Full Text Available The emission and combustion characteristics of a four stroke multi fuel single cylinder variable compression ratio engine fueled with tamanu oil methyl ester and its blends 10%, 20%, 40%, and 60% with diesel (on volume basis are examined and compared with standard diesel. Biodiesel produced from tamanu oil by trans-esterification process has been used in this study. The experiment has been conducted at a constant engine speed of 1500 rpm with 50% load and at compression ratios of 16:1, 17:1, 18:1, 19:1, and 20:1. With different blend and for selected compression ratio the exhaust gas emissions such as CO, HC, NOx, CO2, and the combustion characteristics are measured. The variation of the emission parameters for different compression ratios and for different blends is given, and optimum compression ratio which gives best performance has been identified. The results indicate higher rate of pressure rise and minimum heat release rate at higher compression ratio for tamanu oil methyl ester when compared with standard diesel. The blend B40 for tamanu oil methyl ester is found to give minimum emission at 50% load. The blend when used as fuel results in reduction of polluting gases like HC, CO, and increase in NOx emissions. The previously mentioned emission parameters have been validated with the aid of artificial neural network. A separate model is developed for emission characteristics in which compression ratio, blend percentage and load percentage were used as the input parameter whereas CO, CO2, HC, and NOx were used as the output parameter. This study shows that there is a good correlation between the artificial neural network predicted values and the experimental data for different emission parameters.

  6. A pulse-width modulation controlled wire-mesh heater apparatus for investigation of solid fuel pyrolysis.

    Science.gov (United States)

    Wagner, David Ray; Whitty, Kevin J

    2012-11-01

    A novel wire mesh heater apparatus has been developed to study the devolatilization of solid fuels under pressurized conditions at well-controlled heating rates on the order of 1000 K/s. The apparatus combines direct current and pulse-width modulation with a fast-acting and high current-capacity relay to achieve operating frequencies up to 2000 Hz. This frequency allows much quicker feedback and tighter control of temperature than conventional ac-based systems that operate at 50 to 60 Hz. The present apparatus has been successfully operated at 63 bars with final temperatures of 1473 K and heating rates of 1100 K/s.

  7. A new general and rapid method for investigating hot corrosion: preliminary tests on electrodes for molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, T.R. [Dept. of Chemistry, Univ. of Leeds, Leeds (United Kingdom); Volkovich, V.A. [Dept. of Rare Metals, Ural State Technical Univ. - UPI, Ekaterinburg (Russian Federation)

    2004-07-01

    With the increase and improvement in corrosion resistant alloys, coatings and surface treatments, the ability to test and predict their long-term behaviour to oxidation under hot corrosion conditions, within a reasonable time period, becomes diminished. Peroxide and superoxide ions are the most active oxidisers and we have established a means for generating them in significant concentrations in molten carbonates. This thus has the potential for enabling accelerated hot corrosion studies and we here describe the technique and report preliminary studies on the nickel and nickel oxide electrodes used in molten carbonate fuel cells. Further applications are expected to follow. (orig.)

  8. Experimental investigation on the effect of intake air temperature and air-fuel ratio on cycle-to-cycle variations of HCCI combustion and performance parameters

    Energy Technology Data Exchange (ETDEWEB)

    Maurya, Rakesh Kumar; Agarwal, Avinash Kumar [Engine Research Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2011-04-15

    Combustion in HCCI engines is a controlled auto ignition of well-mixed fuel, air and residual gas. Since onset of HCCI combustion depends on the auto ignition of fuel/air mixture, there is no direct control on the start of combustion process. Therefore, HCCI combustion becomes unstable rather easily, especially at lower and higher engine loads. In this study, cycle-to-cycle variations of a HCCI combustion engine fuelled with ethanol were investigated on a modified two-cylinder engine. Port injection technique is used for preparing homogeneous charge for HCCI combustion. The experiments were conducted at varying intake air temperatures and air-fuel ratios at constant engine speed of 1500 rpm and P-{theta} diagram of 100 consecutive combustion cycles for each test conditions at steady state operation were recorded. Consequently, cycle-to-cycle variations of the main combustion parameters and performance parameters were analyzed. To evaluate the cycle-to-cycle variations of HCCI combustion parameters, coefficient of variation (COV) of every parameter were calculated for every engine operating condition. The critical optimum parameters that can be used to define HCCI operating ranges are 'maximum rate of pressure rise' and 'COV of indicated mean effective pressure (IMEP)'. (author)

  9. The influence of membrane electrode assembly water content on the performance of a polymer electrolyte membrane fuel cell as investigated by 1H NMR microscopy.

    Science.gov (United States)

    Feindel, Kirk W; Bergens, Steven H; Wasylishen, Roderick E

    2007-04-21

    The relation between the performance of a self-humidifying H(2)/O(2) polymer electrolyte membrane fuel cell and the amount and distribution of water as observed using (1)H NMR microscopy was investigated. The integrated (1)H NMR image signal intensity (proportional to water content) from the region of the polymer electrolyte membrane between the catalyst layers was found to correlate well with the power output of the fuel cell. Several examples are provided which demonstrate the sensitivity of the (1)H NMR image intensity to the operating conditions of the fuel cell. Changes in the O(2)(g) flow rate cause predictable trends in both the power density and the image intensity. Higher power densities, achieved by decreasing the resistance of the external circuit, were found to increase the water in the PEM. An observed plateau of both the power density and the integrated (1)H NMR image signal intensity from the membrane electrode assembly and subsequent decline of the power density is postulated to result from the accumulation of H(2)O(l) in the gas diffusion layer and cathode flow field. The potential of using (1)H NMR microscopy to obtain the absolute water content of the polymer electrolyte membrane is discussed and several recommendations for future research are provided.

  10. On the Experimental and Theoretical Investigations of Lean Partially Premixed Combustion, Burning Speed, Flame Instability and Plasma Formation of Alternative Fuels at High Temperatures and Pressures

    Science.gov (United States)

    Askari, Omid

    This dissertation investigates the combustion and injection fundamental characteristics of different alternative fuels both experimentally and theoretically. The subjects such as lean partially premixed combustion of methane/hydrogen/air/diluent, methane high pressure direct-injection, thermal plasma formation, thermodynamic properties of hydrocarbon/air mixtures at high temperatures, laminar flames and flame morphology of synthetic gas (syngas) and Gas-to-Liquid (GTL) fuels were extensively studied in this work. These subjects will be summarized in three following paragraphs. The fundamentals of spray and partially premixed combustion characteristics of directly injected methane in a constant volume combustion chamber have been experimentally studied. The injected fuel jet generates turbulence in the vessel and forms a turbulent heterogeneous fuel-air mixture in the vessel, similar to that in a Compressed Natural Gas (CNG) Direct-Injection (DI) engines. The effect of different characteristics parameters such as spark delay time, stratification ratio, turbulence intensity, fuel injection pressure, chamber pressure, chamber temperature, Exhaust Gas recirculation (EGR) addition, hydrogen addition and equivalence ratio on flame propagation and emission concentrations were analyzed. As a part of this work and for the purpose of control and calibration of high pressure injector, spray development and characteristics including spray tip penetration, spray cone angle and overall equivalence ratio were evaluated under a wide range of fuel injection pressures of 30 to 90 atm and different chamber pressures of 1 to 5 atm. Thermodynamic properties of hydrocarbon/air plasma mixtures at ultra-high temperatures must be precisely calculated due to important influence on the flame kernel formation and propagation in combusting flows and spark discharge applications. A new algorithm based on the statistical thermodynamics was developed to calculate the ultra-high temperature plasma

  11. Certain investigation in a compression ignition engine using rice bran methyl ester fuel blends with ethanol additive

    Directory of Open Access Journals (Sweden)

    Krishnan Arumugam

    2017-01-01

    Full Text Available In this study and analysis, the physical properties such as calorific value, viscosity, flash, and fire point temperatures of rice bran oil methyl ester were found. The rice bran oil biodiesel has been prepared by transesterification process from pure rice bran oil in the presence of methanol and NaOH. Moreover, property enhancement of rice bran oil methyl ester was also made by adding different additives such as ethanol in various proportions. Rice bran oil methyl ester with 1, 3, and 5% ethanol were analyzed for its fuel properties. The effects of diesel-B20ROME blends with ethanol additive of 1, 3, and 5% on a compression ignition engine were examined considering its emissions. It is found that the increase in biodiesel concentration in the fuel blend influences CO2 and NOx emissions. On the other hand CO and HC emissions are reduced. It is interesting to observe the emission as ethanol-B20ROME blends, reduces CO2 and NOx which are the major contributors to global warming. As the NOx and CO2 can be reduced drastically by the proposed blends, the global warming can be reduced considerably.

  12. Analytical and experimental investigation of rubbing interaction in labyrinth seals for a liquid hydrogen fuel pump. [space shuttle main engine

    Science.gov (United States)

    Dolan, F. X.; Kennedy, F. E.; Schulson, E. M.

    1984-01-01

    Cracking of the titanium knife edges on the labyrinth seals of the liquid hydrogen fuel pump in the Space Shuttle main engine is considered. Finite element analysis of the thermal response of the knife edge in sliding contact with the wear ring surface shows that interfacial temperatures can be quite high and they are significantly influenced by the thermal conductivity of the surfaces in rubbing contact. Thermal shock experiments on a test specimen similar to the knife edge geometry demonstrate that cracking of the titanium alloy is possible in a situation involving repeated thermal cycles over a wide temperature range, as might be realized during a rub in the liquid hydrogen fuel pump. High-speed rub interaction tests were conducted using a representative knife edge and seal geometry over a broad range of interaction rates and alternate materials were experimentally evaluated. Plasma-sprayed aluminum-graphite was found to be significantly better than presently used aluminum alloy seals from the standpoint of rub performance. Ion nitriding the titanium alloy knife-edges also improved rub performance compared to the untreated baseline.

  13. Investigation of diesel-ethanol blended fuel properties with palm methyl ester as co-solvent and blends enhancer

    Directory of Open Access Journals (Sweden)

    Mat Taib Norhidayah

    2017-01-01

    Full Text Available Diesel engine is known as the most efficient engine with high efficiency and power but always reported as high fuel emission. Malaysia National Automotive Policy (NAP was targeting to improve competitive regional focusing on green technology development in reducing the emission of the engine. Therefore, ethanol was introduced to reduce the emission of the engine and while increasing its performance, Palm methyl ester was introduced as blend enhancer to improve engine performance and improve diesel-ethanol blends stability. This paper aimed to study the characteristics of the blends and to prove the ability of palm-methyl-ester as co-solvent in ethanol-diesel blends. Stability and thermophysical test were carried out for different fuel compositions. The stability of diesel-ethanol blended was proved to be improved with the addition of PME at the longer period and the stability of the blends changed depending on temperature and ethanol content. Density and viscosity of diesel-ethanol-PME blends also give higher result than diesel-ethanol blends and it's proved that PME is able to increase density and viscosity of blends. Besides, heating value of the blends also increases with the increasing PME in diesel-ethanol blends.

  14. Combined Theoretical and Experimental Investigation and Design of H2S Tolerant Anode for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Gerardine G. Botte; Damilola Daramola; Madhivanan Muthuvel

    2009-01-07

    A solid oxide fuel cell (SOFC) is a high temperature fuel cell and it normally operates in the range of 850 to 1000 C. Coal syngas has been considered for use in SOFC systems to produce electric power, due to its high temperature and high hydrogen and carbon monoxide content. However, coal syngas also has contaminants like carbon dioxide (CO{sub 2}) and hydrogen sulfide (H{sub 2}S). Among these contaminants, H{sub 2}S is detrimental to electrode material in SOFC. Commonly used anode material in SOFC system is nickel-yttria stabilized zirconia (Ni-YSZ). The presence of H{sub 2}S in the hydrogen stream will damage the Ni anode and hinder the performance of SOFC. In the present study, an attempt was made to understand the mechanism of anode (Ni-YSZ) deterioration by H{sub 2}S. The study used computation methods such as quantum chemistry calculations and molecular dynamics to predict the model for anode destruction by H{sub 2}S. This was done using binding energies to predict the thermodynamics and Raman spectroscopy to predict molecular vibrations and surface interactions. On the experimental side, a test stand has been built with the ability to analyze button cells at high temperature under syngas conditions.

  15. Investigation of Lab Fire Prevention Management System of Combining Root Cause Analysis and Analytic Hierarchy Process with Event Tree Analysis

    Directory of Open Access Journals (Sweden)

    Cheng-Chan Shih

    2016-01-01

    Full Text Available This paper proposed a new approach, combining root cause analysis (RCA, analytic hierarchy process (AHP, and event tree analysis (ETA in a loop to systematically evaluate various laboratory safety prevention strategies. First, 139 fire accidents were reviewed to identify the root causes and draw out prevention strategies. Most fires were caused due to runaway reactions, operation error and equipment failure, and flammable material release. These mostly occurred in working places of no prompt fire protection. We also used AHP to evaluate the priority of these strategies and found that chemical fire prevention strategy is the most important control element, and strengthening maintenance and safety inspection intensity is the most important action. Also together with our surveys results, we proposed that equipment design is also critical for fire prevention. Therefore a technical improvement was propounded: installing fire detector, automatic sprinkler, and manual extinguisher in the lab hood as proactive fire protections. ETA was then used as a tool to evaluate laboratory fire risks. The results indicated that the total risk of a fire occurring decreases from 0.0351 to 0.0042 without/with equipment taking actions. Establishing such system can make Environment, Health and Safety (EH&S office not only analyze and prioritize fire prevention policies more practically, but also demonstrate how effective protective equipment improvement can achieve and the probabilities of the initiating event developing into a serious accident or controlled by the existing safety system.

  16. Cardiovascular events in Japanese asymptomatic patients with type 2 diabetes: a 1-year interim report of a J-ACCESS 2 investigation using myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kenichi [Kanazawa University Hospital, Department of Nuclear Medicine, Kanazawa (Japan); Yamasaki, Yoshimitsu [Osaka University, Center for Advanced Science and Innovation, Osaka (Japan); Kusuoka, Hideo [National Hospital Organization Osaka National Hospital, Osaka (Japan); Izumi, Tohru [Kitasato University, Department of Cardiology and Internal Medicine, Sagamihara (Japan); Kashiwagi, Atsunori [Shiga University of Medical Science, Department of Medicine, Ohtsu (Japan); Kawamori, Ryuzo [Juntendo University, Department of Medicine, Metabolism and Endocrinology, School of Medicine, Tokyo (Japan); Shimamoto, Kazuaki [Sapporo Medical University School of Medicine, Second Department of Internal Medicine, Sapporo (Japan); Yamada, Nobuhiro [University of Tsukuba, Division of Metabolism and Endocrinology, Department of Internal Medicine, Faculty of Medicine, Tsukuba (Japan); Nishimura, Tsunehiko [Kyoto Prefectural University of Medicine, Department of Radiology, Graduate School of Medical Science, 465 Kajii-cho, Kawara-machi, Hirokoji, Kamigyo-ku, Kyoto (Japan)

    2009-12-15

    Diabetic patients have a high risk for cardiovascular events. The role of myocardial perfusion imaging was investigated in asymptomatic diabetic patients to evaluate short-term prognosis in a Japanese population. A total of 506 asymptomatic patients {>=}50 years of age who had carotid artery maximum intima-media thickness {>=}1.1 mm, urinary albumin excretion of {>=}30 mg/g creatinine, with additional criteria of abdominal obesity, low HDL cholesterol, high triglyceride level, and hypertension were enrolled and followed up over a 3-year period. Gated SPECT with stress-rest protocol was performed and analyzed by summed defect scores and QGS software. One-year cardiovascular events were analyzed. Myocardial ischemia was observed in 17% of patients, and abnormal perfusion findings of ischemia and/or scar were observed in 32% of patients. By the end of the 1-year follow-up, 33 (6.5%) cardiovascular events occurred including 6 all-cause deaths. Patients with summed stress score (SSS) >8 had a higher incidence of either death or cardiovascular events. Event-free survival rates for SSS 0-3, 4-8, 9-13, and {>=}14 were 0.96, 0.95, 0.82, and 0.76, respectively. Multivariate Cox regression analysis showed that significant variables were SSS, history of cerebrovascular accident, and electrocardiographic abnormality at rest. The 1-year interim summary showed that cardiovascular events were significantly higher in patients with SPECT abnormality, although hard cardiac event rate was relatively low. Targeted treatment strategy is required for asymptomatic but potentially high-risk diabetic patients. (orig.)

  17. An investigation of the factors which influence to the satisfaction with tourist experience of a tourist-visitor of an event in Novi Sad

    Directory of Open Access Journals (Sweden)

    Hadžić Olga

    2006-01-01

    Full Text Available In this paper we investigate factors which influence to the satisfaction with tourist experience of a tourist/visitor of an event, and which are under the control in some extent by the organizer of the event, as well as by the tourism sector of the destination and the local community. A qualitative method (open interview and a quantitative method (the method of Importance/Performance matrix are used.. The results obtained by the application of these methods can help to the organizer of an event, as well as to the tourism sector on the destination, to make an estimation of the successfulness of the event, which is important in the planning process of a similar event in the future. We pointed out the necessity of joint efforts of many partners (stakeholders in tourism sector on the destination in order to satisfy the expectation of a tourist-visitor of the manifestation. Important stakeholders are experts in the domains of the space planning and the protection of the environment. They have to choose in their plans the venue for manifestations and camps for the accommodation of many visitors, which is of the special importance if tourism sector on the destination wish to include in their tourism offer international music manifestations, which attract thousand of tourists.

  18. Numerical investigation of the impact of gas composition on the combustion process in a dual-fuel compression-ignition engine

    NARCIS (Netherlands)

    Mikulski, M.; Wierzbicki, S.

    2016-01-01

    This study discusses the model of operation of a dual-fuel compression-ignition engine, powered by gaseous fuel with an initial dose of diesel fuel as the ignition inhibitor. The study used a zero-dimensional multiphase mathematical model of a dual-fuel engine to simulate the impact of enhancing

  19. Investigation of chemical modifiers for sulfur determination in diesel fuel samples by high-resolution continuum source graphite furnace molecular absorption spectrometry using direct analysis

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Charles S. [Instituto Federal Sul-rio-grandense, Câmpus Pelotas, Pelotas, RS (Brazil); Universidade Federal do Rio Grande do Sul, Instituto de Química, Porto Alegre, RS (Brazil); Vale, Maria Goreti R. [Universidade Federal do Rio Grande do Sul, Instituto de Química, Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Welz, Bernhard [Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Universidade Federal de Santa Catarina, Departamento de Química, Florianópolis, SC (Brazil); Andrade, Jailson B. [Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Dessuy, Morgana B., E-mail: mbdessuy@ufrgs.br [Universidade Federal do Rio Grande do Sul, Instituto de Química, Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil)

    2015-06-01

    High-resolution continuum source graphite furnace molecular absorption spectrometry has been applied for sulfur determination in diesel fuel. The sharp rotational lines of the carbon monosulfide molecule (formed during the vaporization step) were used to measure the absorbance. The analytical line at 258.056 nm was monitored using the sum of three pixels. Different chemical modifiers were investigated and the mixture of palladium and magnesium was used as chemical modifier in combination with iridium as permanent modifier. L-Cysteine was chosen as sulfur standard and the calibration was done against aqueous standard solutions. The proposed method was applied for the analyses of four diesel samples: two S10 samples and two S500 samples. The trueness of the method was checked with a certified reference material (CRM) of sulfur in diesel fuel (NIST 2724b). Accurate results, for samples and CRM, were achieved after a dilution with propan-1-ol. The following figures of merit were obtained: characteristic mass of 17 ± 3 ng, limit of detection and limit of quantification of 1.4 mg kg{sup −1} and 4.7 mg kg{sup −1}, respectively. - Highlights: • Ir, Ru and Zr were investigated as permanent modifiers. • Ca, Mg, Pd and Pd/Mg were investigated as modifiers in solution. • Indirect determination of sulfur monitoring the molecular absorbance of the CS • Direct analysis of diesel samples using a dilution in propan-1-ol.

  20. Event dependent sampling of recurrent events

    DEFF Research Database (Denmark)

    Kvist, Tine Kajsa; Andersen, Per Kragh; Angst, Jules

    2010-01-01

    The effect of event-dependent sampling of processes consisting of recurrent events is investigated when analyzing whether the risk of recurrence increases with event count. We study the situation where processes are selected for study if an event occurs in a certain selection interval. Motivation...

  1. In situ investigation of tubular microbial fuel cells deployed in an aeration tank at a municipal wastewater treatment plant.

    Science.gov (United States)

    Zhang, Fei; Ge, Zheng; Grimaud, Julien; Hurst, Jim; He, Zhen

    2013-05-01

    To examine the feasibility of integrating microbial fuel cells (MFCs) into an activated sludge process, three MFCs with different ion exchange membranes and/or cathode catalysts were installed in an aeration tank to treat primary effluent. Both contaminant treatment and electricity generation were studied during the operation for more than 400 days. The effects of membrane/catalysts on MFC performance were not observed, likely due to the low removal of chemical oxygen demand (COD) (electricity generation. The MFCs did not achieve any obvious removal of nutrients. The produced energy was lower than the theoretic energy consumption. The performance was seriously affected by cathode biofouling, variation of wastewater quality, and other operating conditions. Unlike prior lab studies by others, the results of this study suggest that MFCs may not be suitable for deployment in an aeration tank, unless the key problems such as biofouling are solved. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Investigation of black and brown carbon multiple-wavelength-dependent light absorption from biomass and fossil fuel combustion source emissions

    Science.gov (United States)

    Olson, Michael R.; Victoria Garcia, Mercedes; Robinson, Michael A.; Van Rooy, Paul; Dietenberger, Mark A.; Bergin, Michael; Schauer, James Jay

    2015-07-01

    Quantification of the black carbon (BC) and brown carbon (BrC) components of source emissions is critical to understanding the impact combustion aerosols have on atmospheric light absorption. Multiple-wavelength absorption was measured from fuels including wood, agricultural biomass, coals, plant matter, and petroleum distillates in controlled combustion settings. Filter-based absorption measurements were corrected and compared to photoacoustic absorption results. BC absorption was segregated from the total light extinction to estimate the BrC absorption from individual sources. Results were compared to elemental carbon (EC)/organic carbon (OC) concentrations to determine composition's impact on light absorption. Multiple-wavelength absorption coefficients, Angstrom exponent (6.9 to 0.9 OC/TC), source emissions have variable absorption spectra, and nonbiomass combustion sources can be significant contributors to BrC.

  3. Investigating the effects of proton exchange membrane fuel cell conditions on carbon supported platinum electrocatalyst composition and performance

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Anant; Artyushkova, Kateryna; Atanassov, Plamen; Colbow, Vesna; Dutta, Monica; Harvey, Davie; Wessel, Silvia

    2011-12-01

    Changes that carbon-supported platinum electrocatalysts undergo in a proton exchange membrane fuel cell environment were simulated by ex situ heat treatment of catalyst powder samples at 150 C and 100% relative humidity. In order to study modifications that are introduced to chemistry, morphology, and performance of electrocatalysts, XPS, HREELS and three-electrode rotating disk electrode experiments were performed. Before heat treatment, graphitic content varied by 20% among samples with different types of carbon supports, with distinct differences between bulk and surface compositions within each sample. Following the aging protocol, the bulk and surface chemistry of the samples were similar, with graphite content increasing or remaining constant and Pt-carbide decreasing for all samples. From the correlation of changes in chemical composition and losses in performance of the electrocatalysts, we conclude that relative distribution of Pt particles on graphitic and amorphous carbon is as important for electrocatalytic activity as the absolute amount of graphitic carbon present

  4. Investigating the effects of proton exchange membrane fuel cell conditions on carbon supported platinum electrocatalyst composition and performance

    Energy Technology Data Exchange (ETDEWEB)

    A. Patel; K. Artyushkova; P. Atanassov; V. Colbow; M. Dutta; D. Harvey; S. Wessel

    2012-04-30

    Changes that carbon-supported platinum electrocatalysts undergo in a proton exchange membrane fuel cell environment were simulated by ex situ heat treatment of catalyst powder samples at 150 C and 100% relative humidity. In order to study modifications that are introduced to chemistry, morphology, and performance of electrocatalysts, XPS, HREELS and three-electrode rotating disk electrode experiments were performed. Before heat treatment, graphitic content varied by 20% among samples with different types of carbon supports, with distinct differences between bulk and surface compositions within each sample. Following the aging protocol, the bulk and surface chemistry of the samples were similar, with graphite content increasing or remaining constant and Pt-carbide decreasing for all samples. From the correlation of changes in chemical composition and losses in performance of the electrocatalysts, we conclude that relative distribution of Pt particles on graphitic and amorphous carbon is as important for electrocatalytic activity as the absolute amount of graphitic carbon present

  5. An investigation into the transient behavior of a microreactor system for reforming of Diesel fuel in the kw range

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, G.; Schelhaas, K.P.; Schuerer, J.; Tiemann, D.; Ziogas, A. [Institut fuer Mikrotechnik Mainz GmbH, Mainz (Germany); Hessel, V. [Institut fuer Mikrotechnik Mainz GmbH, Mainz (Germany); Department of Chemical Engineering and Chemistry, Eindhoven University of Technology (Netherlands); O' Connell, M.

    2009-11-15

    A diesel reformer based on microreaction technology was developed for application in an auxiliary power unit (APU) system. The transient characteristics of this reactor for reforming of diesel fuel are reported. Diesel steam reforming was performed at various S/C ratios with load changes ranging from 30 % LL to 80 % LL, i.e., a 1.5 kW to a 4 kW electrical equivalent. The reactor itself was based on an integrated reformer/burner heat exchange reactor concept. The reforming was performed at temperatures above 750 C and at various S/C ratios, down to a minimum of 3.17. Variation of experimental parameters, such as O/C and S/C ratios, are critical for optimum and efficient operation of the reformer. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  6. Fossil fuels -- future fuels

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    Fossil fuels -- coal, oil, and natural gas -- built America`s historic economic strength. Today, coal supplies more than 55% of the electricity, oil more than 97% of the transportation needs, and natural gas 24% of the primary energy used in the US. Even taking into account increased use of renewable fuels and vastly improved powerplant efficiencies, 90% of national energy needs will still be met by fossil fuels in 2020. If advanced technologies that boost efficiency and environmental performance can be successfully developed and deployed, the US can continue to depend upon its rich resources of fossil fuels.

  7. Investigation of the performance decay of anodic PtRu catalyst with working time of direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhen-Bo; Zuo, Peng-Jian; Yin, Ge-Ping [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Wang, Xin-Peng; Yang, Bo-Qian; Feng, Xian-Ping [Department of Physics, University of Puerto Rico, P.O. Box 23343, San Juan, PR 00931 (United States)

    2008-06-15

    Life tests of direct methanol fuel cells (DMFC) were carried out with three individual single cells at a current density of 100 mA cm{sup -2} for three different times under ambient pressure and at a cell temperature of 60 C. X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS) were used to characterize the anodic PtRu catalysts before and after the life tests. XRD results showed that the particle sizes of anodic catalysts increased from an original value of 2.8 to 3.0, 3.2, and 3.3 nm, whereas their lattice parameters first increased and then decreased from an original value of 3.8761 to 3.8879, 3.8777, and 3.8739 Aa before and after 117, 210, and 312 working hours, respectively. XPS results indicated that during cells' working the contents of Pt and Ru oxides in anodic catalysts increased, but the metal content gradually decreased with test times. Polarization curves, power density curves, and in situ CO-stripping cyclic voltammetric (CV) curves were also plotted to evaluate the performances of fuel cells and electrochemically active surface areas (S{sub EAS}) of anodic catalysts before and after life tests. After different time tests, the performances of DMFC lowered to different extents and could not recover their initial performances. The S{sub EAS} of anodic catalyst decreased slightly by 4.78 and 9.03 m{sup 2} g{sup -1} after 117 and 312 working hours, respectively. The utilization of anodic catalysts lowered slightly. This indicates that the change of (S{sub EAS}) and utilization of anodic catalysts are not the main factors affecting the performance degradation of DMFC. The dissolution of Ru metal from anodic catalysts surface could be one of the main factors for the performance degradation of the PtRu black catalyst. (author)

  8. Corrosion investigations on zircaloy-4 and titanium dissolver materials for MOX fuel dissolution in concentrated nitric acid containing fluoride ions

    Energy Technology Data Exchange (ETDEWEB)

    Jayaraj, J.; Krishnaveni, P.; Krishna, D. Nanda Gopala; Mallika, C.; Mudali, U. Kamachi, E-mail: kamachi@igcar.gov.in

    2016-05-15

    Aqueous reprocessing of plutonium-rich mixed oxide fuels require fluoride as a dissolution catalyst in boiling nitric acid for an effective dissolution of the spent fuel. High corrosion rates were obtained for the candidate dissolver materials zircaloy-4 (Zr-4) and commercial pure titanium (CP-Ti grade 2) in boiling 11.5 M HNO{sub 3} + 0.05 M NaF. Complexing the fluoride ions either with Al(NO{sub 3}){sub 3} or ZrO(NO{sub 3}){sub 2} aided in decreasing the corrosion rates of Zr-4 and CP-Ti. From the obtained corrosion rates it is concluded that CP-Ti is a better dissolver material than Zr-4 for extended service life in boiling 11.5 M HNO{sub 3} + 0.05 M NaF, when complexed with 0.15 M ZrO(NO{sub 3}){sub 2}. XPS analysis confirmed the presence of TiO{sub 2} and absence of fluoride on the surface of CP-Ti samples, indicating that effective complexation had occurred in solution leading to passivation of the metal and imparting high corrosion resistance. - Highlights: • Zr-4 and CP-Ti exhibited high corrosion rate in boiling fluorinated nitric acid. • Corrosion rate decreased in fluorinated nitric acid containing ZrO(NO{sub 3}){sub 2} and Al(NO{sub 3}){sub 3}. • High inhibiting efficiency is exhibited by 0.15 M ZrO(NO{sub 3}){sub 2} when compared to Al(NO{sub 3}){sub 3}. • Corrosion rates of CP-Ti were negligible in complexed fluorinated nitric acid. • XPS analysis on CP-Ti confirmed the presence of TiO{sub 2} and absence of fluoride.

  9. Investigating Potential Causes for An Abrupt Change of Thermal State in Earth's Upper Mantle During the Great Oxygenation Event

    Science.gov (United States)

    Li, M.; McNamara, A. K.

    2014-12-01

    The oxygenic photosynthesis might have well evolved about 3 billion years ago, but there seems no great increase of atmospheric oxygen until the great oxygenation event (GOE) at about 2.4 Ga. One possibility for the suppressing of atmospheric oxygen level before the GOE is through consumption of oxygen by reduced volcanic gasses. The amount of atmospheric oxygen that could be consumed by volcanic gases depends on the absolute amount of volcanic gases as well as the redox state of the upper mantle. Evidence from the redox sensitive V/Sc ratio have shown that the redox state of the upper mantle have remained constant for the last 3.5 billion years (e.g., Li and Lee, 2004). If so, abrupt changes in thermal state of Earth's upper mantle could explain the rapid changes of degassing rate at the time of GOE. The Earth's lowermost mantle has been shown to be compositionally heterogeneous, which could be caused by the presence of dense, primordial material resulting from early differentiation processes. An important question is how do chemical heterogeneities in the lowermost mantle influence the secular cooling of the upper mantle. Here, we performed numerical calculations to explore the effects of themochemical convection on the thermal evolution of Earth's upper mantle. A large parameter space is explored, with varying Rayleigh number, viscosity, internal heating and density of chemical heterogeneities. We start with an initially hot mantle with a layer of dense material in the lowermost mantle. We found that when the mantle is hot, the dense material remains layered and covers the entire CMB, leading to low CMB heat flux. In this stage, the upper mantle cools down rapidly. However, as the mantle cools, the dense material is swept into discrete thermochemical piles by cold downwellings, leading to increasing CMB heat flux. The cooling rate of the mantle is temporarily reduced as this transition occurs. This occurs at a time consistent with the GOE event. Li, Z. X. A. and

  10. An event-related potential investigation of the effects of age on alerting, orienting, and executive function

    Directory of Open Access Journals (Sweden)

    David A S Kaufman

    2016-05-01

    Full Text Available The present study compared young and older adults on behavioral and neural correlates of three attentional networks (alerting, orienting, and executive control. Nineteen young and 16 older neurologically-healthy adults completed the Attention Network Test (ANT while behavioral data (reaction time and error rates and 64-channel event-related potentials (ERPs were acquired. Significant age-related RT differences were observed across all three networks; however, after controlling for generalized slowing, only the alerting network remained significantly reduced in older compared with young adults. ERP data revealed that alerting cues led to enhanced posterior N1 responses for subsequent attentional targets in young adults, but this effect was weakened in older adults. As a result, it appears that older adults did not benefit fully from alerting cues, and their lack of subsequent attentional enhancements may compromise their ability to be as responsive and flexible as their younger counterparts. N1 alerting deficits were associated with several key neuropsychological tests of attention that were difficult for older adults. Orienting and executive attention networks were largely similar between groups. Taken together, older adults demonstrated behavioral and neural alterations in alerting, however, they appeared to compensate for this reduction, as they did not significantly differ in their abilities to use spatially informative cues to aid performance (e.g., orienting, or successfully resolve response conflict (e.g., executive control. These results have important implications for understanding the mechanisms of age-related changes in attentional networks.

  11. Pictures of a thousand words: investigating the neural mechanisms of reading with extremely rapid event-related fMRI.

    Science.gov (United States)

    Yarkoni, Tal; Speer, Nicole K; Balota, David A; McAvoy, Mark P; Zacks, Jeffrey M

    2008-08-15

    Reading is one of the most important skills human beings can acquire, but has proven difficult to study naturalistically using functional magnetic resonance imaging (fMRI). We introduce a novel Event-Related Reading (ERR) fMRI approach that enables reliable estimation of the neural correlates of single-word processing during reading of rapidly presented narrative text (200-300 ms/word). Application to an fMRI experiment in which subjects read coherent narratives and made no overt responses revealed widespread effects of orthographic, phonological, contextual, and semantic variables on brain activation. Word-level variables predicted activity in classical language areas as well as the inferotemporal visual word form area, specifically supporting a role for the latter in mapping visual forms onto articulatory or acoustic representations. Additional analyses demonstrated that ERR results replicate across experiments and predict reading comprehension. The ERR approach represents a powerful and extremely flexible new approach for studying reading and language behavior with fMRI.

  12. Couple adjustment to a stressful life event: a dyadic investigation of the roles of positive reframing and perceived benefits.

    Science.gov (United States)

    Samios, Christina; Baran, Shayne

    2018-03-01

    This study examines positive reframing (a form of meaning making), perceived benefits (a form of meanings made) and adjustment in couples who experienced a stressful life event in the past year. This study tested whether couple members' scores were nonindependent and whether one's own perceived benefits was predicted by their own positive reframing (actor effect) as well as their partner's positive reframing (partner effect). Further, this study tested actor and partner effects for the link between perceived benefits and adjustment and whether positive reframing (the initial variable) works through perceived benefits (the mediator) to affect adjustment (the outcome) at the dyadic level. A standard dyadic design was used. Eighty couples completed measures of positive reframing, perceived benefits, and adjustment (depression, anxiety, positive affect, life satisfaction, and relationship satisfaction). Partners' scores on study variables were related, and although only actor effects were found for the path between positive reframing and perceived benefits, both actor and partner effects were found for the path between perceived benefits and adjustment. Mediation was found for actor-actor and actor-partner indirect effects. Results indicate that a greater focus on interpersonal factors is needed to further meaning-making theory and inform practice.

  13. Using Discrepant Events in Science Demonstrations to Promote Student Engagement in Scientific Investigations: An Action Research Study

    Science.gov (United States)

    Mancuso, Vincent J.

    2010-01-01

    Students' scientific investigations have been identified in national standards and related reform documents as a critical component of students' learning experiences in school, yet it is not easy to implement them in science classrooms. Could science demonstrations help science teachers put this recommendation into practice? While demonstrations…

  14. Investigating the interactive role of stressful life events, reinforcement sensitivity and personality traits in prediction of the severity of Multiple Sclerosis (MS symptoms

    Directory of Open Access Journals (Sweden)

    2017-06-01

    Full Text Available Background & Objective: Multiple sclerosis is a chronic neurological condition recognized by demyelination in the central nervous system. The present study was conducted to investigate the interactive role of stressful life events, reinforcement sensitivity, and personality traits in prediction of the severity of symptoms of Multiple sclerosis (MS symptoms. Materials & Methods: This is a correlational study whose statistical population consisted of all the patients suffering from Multiple Sclerosis in Shiraz in the first half of 1394, among whom 162 patients were included in this research by means of purposive sampling method. Five-Factor Personality Inventory, Jackson Personality Inventory, Stressful Life Events Scale, and Expanded Disability Status Scale (EDSS were utilised as research tools. In order to analyze the data, descriptive and inferential methods were used. The data were analysed using Pearson correlation and hierarchical regression. Results: The findings revealed that stressful life events (β = 0.41, p <0.001, Behavioral Inhibition System (β = 0.26, p<0.05, and neuroticism index (β = 0.92, p <0.05 were able to predict variance of scores of the severity of symptoms of Multiple Sclerosis significantly. Conclusion: Stressful life events, Behavioral Inhibition System, and neuroticism showed a significant relationship with the severity of symptoms of Multiple Sclerosis; thus, it seems that interaction of personality traits and environmental conditions are among influential factors of the severity of symptoms of Multiple Sclerosis. This fact implies that individuals' personal traits play an eminent role in the progression of the disease.

  15. Experimental modelling of wave amplification over irregular bathymetry for investigations of boulder transport by extreme wave events.

    Science.gov (United States)

    O'Boyle, Louise; Whittaker, Trevor; Cox, Ronadh; Elsäßer, Björn

    2017-04-01

    nearshore multibeam sonar survey. Water surface elevation is recorded using twin-wire resistance type wave probes along a shore-normal bathymetry transect as the waves shoal. Variations in significant wave height and maximum elevation are presented for both regular and irregular bathymetry and for a number of typical North Atlantic sea states. These results are significant for calibration of numerical wave propagation models over irregular bathymetry and for those seeking to understand the magnitude of nearshore extreme wave events. References [1] Met Éireann, 2014, Winter 2013/2014: Monthly Weather Bulletin, December issue, p. 1-5. http://www.met.ie/climate-ireland/weather-events/winterstorms13_14.pdf. [2] Cox, R. et. al., 2016, Movement of boulders and megagravel by storm waves Vol. 18, EGU2016-10535, 2016 EGU General Assembly 2016

  16. DUPIC fuel compatibility assessment

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hang Bok; Rho, G. H.; Park, J. W. [and others

    2000-03-01

    The purpose of this study is to assess the compatibility of DUPIC(Direct Use of Spent PWR Fuel in CANDU Reactors) fuel with the current CANDU 6 reactor, which is one of the technology being developed to utilize the spent PWR fuel in CANDU reactors. The phase 1 study of this project includes the feasibility analysis on applicability of the current core design method, the feasibility analysis on operation of the DUPIC fuel core, the compatibility analysis on individual reactor system, the sensitivity analysis on the fuel composition, and the economic analysis on DUPIC fuel cycle. The results of the validation calculations have confirmed that the current core analysis system is acceptable for the feasibility study of the DUPIC fuel compatibility analysis. The results of core simulations have shown that both natural uranium and DUPIC fuel cores are almost the same from the viewpoint of the operational performance. For individual reactor system including reactively devices, the functional requirements of each system are satisfied in general. However, because of the pronounced power flattening in the DUPIC core, the radiation damage on the critical components increases, which should be investigated more in the future. The DUPIC fuel composition heterogeneity dose not to impose any serious effect on the reactor operation if the fuel composition is adjusted. The economics analysis has been performed through conceptual design studies on the DUPIC fuel fabrication, fuel handling in a plant, and spent fuel disposal, which has shown that the DUPIC fuel cycle is comparable to the once-trough fuel cycle considering uncertainties associated with unit costs of the fuel cycle components. The results of Phase 1 study have shown that it is feasible to use the DUPIC fuel in CANDU reactors without major changes in hardware. However further studies are required to confirm the safety of the reactor under accident condition.

  17. Investigating SO3 Formation from the Combustion of Heavy Fuel Oil in a Four-Stroke Medium Speed Test Engine

    DEFF Research Database (Denmark)

    Cordtz, Rasmus Lage; Schramm, Jesper; Rabe, Rom

    2013-01-01

    The validation of detailed models, in terms of SO3 formation in large marine engines operating on sulfur-containing heavy fuel oils (HFOs), relies on experimental work. The requisite is addressed in the present work, where SO3 is measured in the exhaust gas of an 80 kW medium-speed single......-cylinder HFO-fuelled test engine. SO3 formation is triggered by running the engine at altered operational conditions and speeds within 1050−1500 rpm. The test engine does not represent a large low-speed marine engine; however, the nature of high-temperature SO3 formation may well be explored with the current...... engine and serve as reference for further modeling studies. SO3 is measured using a continuous SO3 monitor from PENTOL GmbH. The monitor offers online SO3 readings and short sampling times, in contrast to other extractive methods. The measurement is based on SO3 capture in isopropanol prior to chemical...

  18. Numerical and Experimental Investigation of a Supersonic Flow Field around Solid Fuel on an Inclined Flat Plate

    Directory of Open Access Journals (Sweden)

    Uzu-Kuei Hsu

    2009-01-01

    Full Text Available This research adopts a shock tube 16 meters long and with a 9 cm bore to create a supersonic, high-temperature, and high-pressure flowfield to observe the gasification and ignition of HTPB solid fuel under different environments. Also, full-scale 3D numerical simulation is executed to enhance the comprehension of this complex phenomenon. The CFD (Computational Fluid Dynamics code is based on the control volume method and the pre-conditioning method for solving the Navier-Stokes equations to simulate the compressible and incompressible coupling problem. In the tests, a HTPB slab is placed in the windowed-test section. Various test conditions generate different supersonic Mach numbers and environmental temperatures. In addition, the incident angles of the HTPB slab were changed relative to the incoming shock wave. Results show that as the Mach number around the slab section exceeded 1.25, the flowfield temperature achieved 1100 K, which is higher than the HTPB gasification temperature (930 K ~ 1090 K. Then, gasification occurred and a short-period ignition could be observed. In particular, when the slab angle was 7∘, the phenomenon became more visible. This is due to the flow field temperature increase when the slab angle was at 7∘.

  19. High-quality fuel from food waste - investigation of a stepwise process from the perspective of technology development.

    Science.gov (United States)

    Yin, Ke; Li, Ling; Giannis, Apostolos; Weerachanchai, Piyarat; Ng, Bernard J H; Wang, Jing-Yuan

    2017-07-01

    A stepwise process (SP) was developed for sustainable energy production from food waste (FW). The process comprised of hydrothermal treatment followed by oil upgrading. Synthetic food waste was primarily used as feedstock in the hydrothermal reactor under subcritical water conditions. The produced hydrochars were analyzed for calorific value (17.0-33.7 MJ/kg) and elemental composition indicating high-quality fuel comparable to coal. Hydrothermal carbonization (e.g. 180°C) would be efficient for oil recovery (>90%) from FW, as compared to hydrothermal liquefaction (320°C) whereby lipid degradation may take place. The recovered oil was upgraded to biodiesel in a catalytic refinery process. Selected biodiesels, that is, B3 and B4 were characterized for density (872.7 and 895.5 kg/m3), kinematic viscosity (3.115 and 8.243 cSt), flash and pour point (30°C and >126°C), micro carbon (0.03% and 0.04%), sulfur (both biofuel and hydrochar production.

  20. Investigacion experimental de la prestaciones de un motor monocilíndrico usando combustible diesel emulsionado; Experimental investigation of the single cylinder engine performance using emulsified diesel fuel

    Directory of Open Access Journals (Sweden)

    Eliezer Ahmed- Melo Espinosa y otros

    2013-01-01

    Full Text Available En esta investigación se realiza un análisis de las prestaciones y emisiones de un motor Petter mono-cilíndrico de inyección directa al usar como combustible una emulsión de 5% de agua, 2% de surfactante y combustible diesel. Los resultados obtenidos con la emulsión muestran un ligero incremento en el torque y la potencia efectiva, así como en el consumo específico de combustible y el retardo de la ignición. Respecto a las emisiones de gases contaminantes, los hidrocarburos noquemados (HC y el monóxido de carbono (CO para la emulsió aumentaron en comparación con los resultados obtenidos para el combustible diesel. En ambos casos, los aumentos son unaconsecuencia de la disminución de las temperaturas en el interior de la cámara de combustión, los aumentos en el retardo de la ignición y al enfriamiento de la llama.In this investigation an analysis based on the performances and emission of a Petter single cylinderdirect injection diesel engine when using an emulsion of 5% of water, 2% of surfactant and diesel fuel as fuel is carried out. The result obtained with the emulsion tested shown slight increase ineffective torque and power output, but also increases in brake specific fuel consumption and ignition delay. Concerning the exhausts, increases in hydrocarbons (HC and carbon monoxide(CO emissions for emulsion were obtained. In both cases the increases are due to the effect of lower temperatures inside the combustion chamber, longer ignition delays and quenching of theflame.

  1. Development, investigation and modelling of a micro reformer as part of a system for off-grid power supply with PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Rochlitz, Lisbeth

    2008-11-18

    In this thesis a micro reformer fuel cell system ({mu}RFCS) for 300 Wel off-grid power supply, fuelled with bioethanol, was simulated, designed, developed and investigated in a test-rig. First a literature study was carried through to point out the specific characteristics of micro reforming, the most important being heat transfer, and present the systems currently under research and already on the market. As a next step, the processes of the RFCS were simulated with the commercial simulation tool CHEMCAD. This comprised thermodynamic equilibrium simulations for the separate reactions of steam reforming, water gas shift and selective methanation. It also included a simulation of the complete {mu}RFCS with thermodynamic equilibrium for all reactors and assumed values for heat loss and fuel cell efficiency. The resulting net electrical efficiency was 24%. As a third step, a reaction pathway scheme with parallel and serial reactions for the steam reforming reaction of ethanol was simulated, developed, evaluated and proven plausible by matching the simulation to experimental results obtained in the {mu}RFCS test rig. The equilibrium simulations were used to evaluate the catalyst screening carried through for reformer, water gas shift and selective methanation catalysts. The catalysts for the {mu}RFCS were chosen and the optimum operating conditions determined by the screening tests. Having accomplished the simulation and design of the system, the largest proportion of this work was spent on the construction, set-up, testing and evaluation of the complete {mu}RFCS. The focus for the evaluations lay on the reformer side of the system. The technical feasibility was demonstrated for an ethanol/water mix of 3 ml/min at S/C 3. The first tests without optimized heat and water management between the reformer system and the fuel cell system resulted in power output of around 115 W{sub el}, at a total electrical efficiency of 31%. (orig.)

  2. Numerical investigation on the effect of injection pressure on the internal flow characteristics for diethyl ether, dimethyl ether and diesel fuel injectors using CFD

    Directory of Open Access Journals (Sweden)

    Vijayakumar Thulasi

    2011-01-01

    Full Text Available The spray characteristics of the diesel fuel are greatly affected by the cavitation formed inside the injector due to the high pressure differential across the nozzle. Many researchers across the globe are exploring the potential of using diethyl ether and dimethyl ether as an alternate for diesel fuel to meet the strict emission norms. Due to the variation in the fuel properties the internal flow characteristics in injectors for ether fuels are expected to be different from that of the diesel fuel. In this paper computational technique is used to study and compare the internal flow characteristics of diethyl ether, dimethyl ether and diesel fuel. The two phase flow model considering the fuel as a mixture of liquid and vapor is adopted for the simulation study. The injection pressure is varied from 100 to 400 bar and the flow characteristics of all three fuels are simulated and compared. Results indicate that all three fuels have distinct cavitating patterns owing to different property values. The dimethyl ether is found to be more cavitating than diesel and diethyl ether fuels as expected. The mass of fuel injected are found to be decreasing for the ether fuels when compared with diesel fuel at all injection pressures.

  3. Research investigations in oil shale, tar sand, coal research, advanced exploratory process technology, and advanced fuels research: Volume 1 -- Base program. Final report, October 1986--September 1993

    Energy Technology Data Exchange (ETDEWEB)

    Smith, V.E.

    1994-05-01

    Numerous studies have been conducted in five principal areas: oil shale, tar sand, underground coal gasification, advanced process technology, and advanced fuels research. In subsequent years, underground coal gasification was broadened to be coal research, under which several research activities were conducted that related to coal processing. The most significant change occurred in 1989 when the agreement was redefined as a Base Program and a Jointly Sponsored Research Program (JSRP). Investigations were conducted under the Base Program to determine the physical and chemical properties of materials suitable for conversion to liquid and gaseous fuels, to test and evaluate processes and innovative concepts for such conversions, to monitor and determine environmental impacts related to development of commercial-sized operations, and to evaluate methods for mitigation of potential environmental impacts. This report is divided into two volumes: Volume 1 consists of 28 summaries that describe the principal research efforts conducted under the Base Program in five topic areas. Volume 2 describes tasks performed within the JSRP. Research conducted under this agreement has resulted in technology transfer of a variety of energy-related research information. A listing of related publications and presentations is given at the end of each research topic summary. More specific and detailed information is provided in the topical reports referenced in the related publications listings.

  4. Investigations on autothermal reforming of kerosene Jet A-1 for supplying solid oxide fuel cells (SOFC); Untersuchungen zur autothermen Reformierung von Kerosin Jet A-1 zur Versorgung oxidkeramischer Festelektrolyt-Brennstoffzellen (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Lenz, B.

    2007-01-25

    The auxiliary power unit of commercial aircraft is a gas turbine producing electric power with an efficiency of 18 %. This APU can be replaced by a fuel cell system, consisting of an autothermal kerosene reformer and a solid oxide fuel cell (SOFC). The fuel is kerosene Jet A-1. The autothermal reforming of Jet A-1 is practically investigated under variation of steam-to-carbon-ratio, air ratio, space velocity, time in operation and reactor pressure on commercial catalysts. Using stationary system simulation the thermodynamic processes of the device is investigated. Finally, the autothermal reformer and the SOFC consisting of 14 cells are coupled. During this test series, I-V-characteristics are measured, fuel utilisation is calculated and the self-sufficient system operation is shown. (orig.)

  5. Offender Mobility During the Crime: Investigating the Variability of Crime Event Contexts and Associated Outcomes in Stranger Sexual Assaults.

    Science.gov (United States)

    Hewitt, Ashley; Beauregard, Eric

    2017-06-01

    Using data from qualitative interviews and police reports, latent class analysis is used on a sample of 54 repeat stranger sexual offenders who committed 204 sexual assaults to identify discrete contexts present at the time of victim encounter that influence these offenders' decision to use more than one location to commit their crimes. Five distinct classes are identified: residential outdoor common area, spontaneous/quiet outdoor site, residential home, active green space, and indoor/public gathering place. An investigation into the outcome(s) that most often result from the offender's decision to move the victim during the sexual assault indicates that those who move the victim from an active green space overwhelmingly engage in sexual penetration, as well as forcing their victims to commit sexual acts on them. Crimes where the victim is moved from a residential home show evidence of the offender physically harming the victim as well as using more force than necessary to complete the assault. Implications for situational crime prevention are discussed.

  6. Investigation of local meteorological events and their relationship with ozone and aerosols during an ESCOMPTE photochemical episode

    Directory of Open Access Journals (Sweden)

    P. Augustin

    2006-11-01

    Full Text Available The international ESCOMPTE campaign, which took place in summer 2001 in the most highly polluted French region, was devoted to validate air pollution prediction models. Surface and remote sensing instruments (Lidar, Radar and Sodar were deployed over the Marseille area, along the Mediterranean coast, in order to investigate the fine structure of the sea-breeze circulation and its relationship with the pollutant concentrations. The geographical situation of the Marseille region combines a complex coastline and relief which both lead to a peculiar behaviour of the sea-breeze circulation. Several local sea breezes, perpendicular to the nearest coastline, settled in during the morning. In the afternoons, when the thermal gradient between the continental and marine surface grows up, a southerly or a westerly sea breeze may dominate. Their respective importance is then a function of time, space and altitude. Furthermore, an oscillation of the westerly sea breeze with a period of about 3 h is also highlighted. We show that these dynamical characteristics have profound influences on the atmospheric boundary-layer (ABL development and on pollutant concentrations. In fact, the direction and intensity of the sea-breeze determine the route and the transit time of the stable marine air flow over the continental surface. Thus, the ABL depth may exhibit several collapses correlated with the westerly sea-breeze pulsation. The ozone and aerosol concentrations are also related to the dynamical features. In the suburbs and parts of the city under pulsed sea breezes, a higher ABL depth and higher ozone concentrations are observed. In the city centre, this relationship between pulsed sea-breeze intensity and ozone concentration is different, emphasising the importance of the transit time and also the build-up of pollutants in the marine air mass along the route. Finally, the variations of aerosol concentration are also described according to the breeze direction.

  7. Investigation of the efect of the coal particle sizes on the interfacial and rheological properties of coal-water slurry fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kihm, K.D.; Deignan, P. [Texas A& M Univ., College Station, TX (United States)

    1995-11-01

    Experiments were conducted to investigate the effect of particle size on coal-water slurry (CWS) surface tension properties. Two different coal powder samples of different size ranges were obtained through sieving of coal from the Upper Elkhorn Seam. The surfactant (anionic DDBS-soft, dodecylbenzene sulfonic acid) concentration varied from 0 to 1.0% in weight while the coal loading remained at 40% in weight for all the cases. A du Nouy ring tensiometer and a maximum bubble pressure tensiometer measured the static and dynamic surface tensions, respectively, The results show that both static and dynamic surface tensions tend to increase with decreasing coal particle sizes suspended in CWS fuels. Examination of the peak pressure, minimum pressure, surfactant diffusion time, and dead time were also made to correlate these microscopic pressure behavior with the macroscopic dynamic surface tension and to examine the accuracy of the experiment.

  8. Final disposal of spent fuel in the Finnish bedrock. Detailed site investigations 1993-1996; Kaeytetyn polttoaineen loppusijoitus Suomen kallioperaeaen. Yksityiskohtaiset sijoituspaikkatutkimukset 1993-1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    Posiva Oy, jointly owned company of Imatran Voima Oy (IVO) and Teollisuuden Voima Oy (TVO), studies the Finnish bedrock for the final disposal of the spent nuclear fuel. The study is in accordance with the decision in principle by Finnish government in 1983 and aims at site selection. The report is the summary of the first stage of the detailed site investigations carried out during the years 1993-1996. The three sites in question, Romuvaara in Kuhmo, Kivetty in Aeaenekoski and Olkiluoto in Eurajoki were selected for the detailed characterization on the basis of the preliminary site investigations at five areas. The interim reporting in 1996 is comprehensive and comprises a series of reports covering different disciplines and sites. The programme for 1993-1996 was divided into three sub-programs: (1) the baseline investigations describing the present conditions in the bedrock, (2) the additional characterization for the acquisition of complementary data, and (3) the investigations for testing the earlier results and hypotheses to build confidence in existing understanding. (refs.).

  9. Thermal engineering research. [Runge-Kutta investigation of gas flow inside multilayer insulation system for rocket booster fuel tanks

    Science.gov (United States)

    Shih, C. C.

    1973-01-01

    A theoretical investigation of gas flow inside a multilayer insulation system has been made for the case of the broadside pumping process. A set of simultaneous first-order differential equations for the temperature and pressure of the gas mixture was obtained by considering the diffusion mechanism of the gas molecules through the perforations on the insulation layers. A modified Runge-Kutta method was used for numerical experiment. The numerical stability problem was investigated. It has been shown that when the relaxation time is small compared with the time period over which the gas properties change appreciably, the set of differential equations can be replaced by a set of algebraic equations for solution. Numerical examples were given, and comparisons with experimental data were made.

  10. Preliminary Modeling of Accident Tolerant Fuel Concepts under Accident Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gamble, Kyle A.; Hales, Jason D.

    2016-12-01

    The catastrophic events that occurred at the Fukushima-Daiichi nuclear power plant in 2011 have led to widespread interest in research of alternative fuels and claddings that are proposed to be accident tolerant. Thus, the United States Department of Energy through its NEAMS (Nuclear Energy Advanced Modeling and Simulation) program has funded an Accident Tolerant Fuel (ATF) High Impact Problem (HIP). The ATF HIP is funded for a three-year period. The purpose of the HIP is to perform research into two potential accident tolerant concepts and provide an in-depth report to the Advanced Fuels Campaign (AFC) describing the behavior of the concepts, both of which are being considered for inclusion in a lead test assembly scheduled for placement into a commercial reactor in 2022. The initial focus of the HIP is on uranium silicide fuel and iron-chromium-aluminum (FeCrAl) alloy cladding. Utilizing the expertise of three national laboratory participants (INL, LANL, and ANL) a comprehensive mulitscale approach to modeling is being used including atomistic modeling, molecular dynamics, rate theory, phase-field, and fuel performance simulations. In this paper, we present simulations of two proposed accident tolerant fuel systems: U3Si2 fuel with Zircaloy-4 cladding, and UO2 fuel with FeCrAl cladding. The simulations investigate the fuel performance response of the proposed ATF systems under Loss of Coolant and Station Blackout conditions using the BISON code. Sensitivity analyses are completed using Sandia National Laboratories’ DAKOTA software to determine which input parameters (e.g., fuel specific heat) have the greatest influence on the output metrics of interest (e.g., fuel centerline temperature). Early results indicate that each concept has significant advantages as well as areas of concern. Further work is required prior to formulating the proposition report for the Advanced Fuels Campaign.

  11. Experimental analysis of methanol cross-over in a direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Casalegno, Andrea [Dipartimento di Energetica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy)]. E-mail: andrea.casalegno@polimi.it; Grassini, Paolo [Dipartimento di Energetica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy)]. E-mail: PGrassini@seal.it; Marchesi, Renzo [Dipartimento di Energetica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy)]. E-mail: renzo.marchesi@polimi.it

    2007-03-15

    Methanol cross-over through the polymeric membrane is one of the main causes limiting direct methanol fuel cell performances. It causes fuel wasting and enhances cathode overpotential. A repeatable and reproducible measurement system, that assures the traceability of the measurement to international reference standards, is necessary to compare different fuel cell construction materials. In this work a method to evaluate methanol cross-over rate and operating condition influence is presented and qualified in term of measurement uncertainty. In the investigated range, the methanol cross-over rate results mainly due to diffusion through the membrane, in fact it is strongly affected by temperature. Moreover the cross-over influence on fuel utilization and fuel cell efficiency is investigated. The methanol cross-over rate appears linearly proportional to electrochemical fuel utilization and values, obtained by measurements at different anode flow rate but constant electrochemical fuel utilization, are roughly equal; methanol wasting, due to cross-over, is considerable and can still be higher than electrochemical utilization. The fuel recirculation effect on energy efficiency has been investigated and it was found that fuel recirculation gives more advantage at low temperature, but fuel cell energy efficiency results are in any event higher at high temperature.

  12. Experimental investigation of convective boiling in mini-channels: Cooling application of the proton exchange membrane fuel cells

    Directory of Open Access Journals (Sweden)

    Boudouh Mounir

    2017-01-01

    Full Text Available An experimental study of convective boiling heat transfer of water flowing in minichannels at low flow rate is carried out with pure de-ionised water and copper-water nanofluids. A low concentration of copper nanometer-sized particles was used to enhance the boiling heat transfer. The aim is to characterize the surface temperature as well as to estimate the local heat transfer coefficients by using the inverse heat conduction problem IHCP. The inlet water temperature is fixed at 60°C and mass fluxes operated in range of 212-573 kg/m².s in minichannels of dimensions 500×2000 μm². The maximum heat flux investigated in the tests is limited to 7000 W/m². The results show that the surface temperature and the local heat transfer coefficient are dependent on the axial location and the adding of copper nanoparticles can significantly improve the heat transfer.

  13. Investigacion experimental de la prestaciones de un motor monocilíndrico usando combustible diesel emulsionado; Experimental investigation of the single cylinder engine performance using emulsified diesel fuel

    Directory of Open Access Journals (Sweden)

    Eliezer Ahmed Melo Espinosa

    2015-04-01

    Full Text Available En esta investigación se realiza un análisis de las prestaciones y emisiones de un motor Petter mono-cilíndrico de inyección directa al usar como combustible una emulsión de 5% de agua, 2%de surfactante y combustible diesel. Los resultados obtenidos con la emulsión muestran un ligero incremento en el torque y la potencia efectiva, así como en el consumo específico de combustible y el retardo de la ignición. Respecto a las emisiones de gases contaminantes, los hidrocarburos noquemados (HC y el monóxido de carbono (CO para la emulsión aumentaron en comparación con los resultados obtenidos para el combustible diesel. En ambos casos, los aumentos son unaconsecuencia de la disminución de las temperaturas en el interior de la cámara de combustión, los aumentos en el retardo de la ignición y al enfriamiento de la llama. In this investigation an analysis based on the performances and emission of a Petter single cylinder direct injection diesel engine when using an emulsion of 5% of water, 2% of surfactant and dieselfuel as fuel is carried out. The result obtained with the emulsion tested shown slight increase in effective torque and power output, but also increases in brake specific fuel consumption and ignition delay. Concerning the exhausts, increases in hydrocarbons (HC and carbon monoxide(CO emissions for emulsion were obtained. In both cases the increases are due to the effect of lower temperatures inside the combustion chamber, longer ignition delays and quenching of the flame.

  14. TEM and XAS investigation of fission gas behaviors in U-Mo alloy fuels through ion beam irradiation

    Science.gov (United States)

    Zang, Hang; Yun, Di; Mo, Kun; Wang, Kunpeng; Mohamed, Walid; Kirk, Marquis A.; Velázquez, Daniel; Seibert, Rachel; Logan, Kevin; Terry, Jeffrey; Baldo, Peter; Yacout, Abdellatif M.; Liu, Wenbo; Zhang, Bo; Gao, Yedong; Du, Yang; Liu, Jing

    2017-10-01

    In this study, smaller-grained (hundred nano-meter size grain) and larger-grained (micro-meter size grain) U-10Mo specimens have been irradiated (implanted) with 250 keV Xe+ beam and were in situ characterized by TEM. Xe bubbles were not seen in the specimen after an implantation fluence of 2 × 1020 ions/m2 at room temperature. Nucleation of Xe bubbles happened during heating of the specimen to a final temperature of 300 °C. By comparing measured Xe bubble statistics, the nucleation and growth behaviors of Xe bubbles were investigated in smaller-grained and larger-grained U-10Mo specimens. A multi-atom kind of nucleation mechanism has been observed in both specimens. X-ray Absorption spectroscopy showed the edge position in the bubbles to be the same as that of Xe gas. The size of Xe bubbles has been shown to be bigger in larger-grained specimens than in smaller-grained specimens at the same implantation conditions.

  15. Integrated account of method, site selection and programme prior to the site investigation phase[Planning for a Swedish repository for spent nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-12-01

    In order to dispose of the spent nuclear fuel in a safe manner, SKB plans to site a deep repository and an encapsulation plant with associated canister fabrication and transportation system. After an integrated evaluation of feasibility studies and other material, SKB will proceed with investigations of the rock and studies regarding establishment of the deep disposal system in the municipality of Oskarshamn or in Northern Uppland. The plans also include further study of the prospects for a deep repository in the municipality of Nykoeping. In the municipality of Oskarshamn, SKB plans further studies of a siting of the deep repository at Simpevarp. There SKB wants to initiate site investigations with test drilling. For the encapsulation plant, SKB wants to continue studying a siting at CLAB. In Northern Uppland, SKB plans to study two siting alternatives for the deep repository. One is Forsmark in the municipality of Oesthammar, where SKB wants to initiate a site investigation with test drilling. The other is Tierp north of Skutskaer, where SKB intends to start test drilling in an area north of Tierp. First, however, a suitable drilling area with possible transport solutions needs to be defined. This alternative requires the participation of the municipalities of both Tierp and Aelvkarleby. A siting of the encapsulation plant in Northern Uppland will also be studied. For the municipality of Nykoeping, SKB plans to conduct a new safety assessment for the Fjaellveden area, based on data from previous investigations as well as additional studies of how a deep repository could be arranged. SKB will thereby gather data from yet another geographic and geological region beyond those that are prioritized. No test drilling is planned in Nykoeping. The goal of the site investigation phase is to obtain all permits needed to build the planned facilities. It will take an estimated 7 - 8 years to assemble the requisite supporting material, carry out consultations, compile siting

  16. Investigation of truck size and weight limits: technical supplement. Volume 3. Truck and rail fuel effects of truck size and weight limits. Final report, October 1978-June 1981

    Energy Technology Data Exchange (ETDEWEB)

    Knapton, D.A.

    1981-07-01

    Data and indirect fuel consumption for new truck size and weight limits are presented. These effects are examined in terms of changes in the competitive relationships between highway and rail services. The method for estimating fuel consumption includes line haul and access fuel and makes allowance for the system fuel requirements of empty backhaul and circuitry. Single unit trucks, conventional tractor-semi-trailer, Western Doubles, Turnpike Doubles, and Triple Trailer combination rigs as well as the competitive carload boxcar and TOFC rail services are considered. Truck service (i.e., van, reefer, household moving van, flat bed, tanker and dump), and the competitive rail services are disaggregated.

  17. Investigation on electrical surface modification of waste to energy ash for possible use as an electrode material in microbial fuel cells.

    Science.gov (United States)

    Webster, Megan; Lee, Hae Yang; Pepa, Kristi; Winkler, Nathan; Kretzschmar, Ilona; Castaldi, Marco J

    2018-01-01

    With the world population expected to reach 8.5 billion by 2030, demand for access to electricity and clean water will grow at unprecedented rates. Municipal solid waste combusted at waste to energy (WtE) facilities decreases waste volume and recovers energy, but yields ash as a byproduct, the beneficial uses of which are actively being investigated. Ash is intrinsically hydrophobic, highly oxidized, and exhibits high melting points and low conductivities. The research presented here explores the potential of ash to be used as an electrode material for a microbial fuel cell (MFC). This application requires increased conductivity and hydrophilicity, and a lowered melting point. Three ash samples were investigated. By applying an electric potential in the range 50-125 V across the ash in the presence of water, several key property changes were observed: lower melting point, a color change within the ash, evidence of changes in surface morphologies of ash particles, and completely wetting water-ash contact angles. We analyzed this system using a variety of analytical techniques including sector field inductively coupled plasma mass spectrometry, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and tensiometry. Ability to make such surface modifications and significant property changes could allow ash to become useful in an application such as an electrode material for a MFC.

  18. Fuel cell catalyst degradation

    DEFF Research Database (Denmark)

    Arenz, Matthias; Zana, Alessandro

    2016-01-01

    Fuel cells are an important piece in our quest for a sustainable energy supply. Although there are several different types of fuel cells, the by far most popular is the proton exchange membrane fuel cell (PEMFC). Among its many favorable properties are a short start up time and a high power density...... increasing focus. Activity of the catalyst is important, but stability is essential. In the presented perspective paper, we review recent efforts to investigate fuel cell catalysts ex-situ in electrochemical half-cell measurements. Due to the amount of different studies, this review has no intention to give...

  19. HTPEM Fuel Cell Impedance

    DEFF Research Database (Denmark)

    Vang, Jakob Rabjerg

    As part of the process to create a fossil free Denmark by 2050, there is a need for the development of new energy technologies with higher efficiencies than the current technologies. Fuel cells, that can generate electricity at higher efficiencies than conventional combustion engines, can...... potentially play an important role in the energy system of the future. One of the fuel cell technologies, that receives much attention from the Danish scientific community is high temperature proton exchange membrane (HTPEM) fuel cells based on polybenzimidazole (PBI) with phosphoric acid as proton conductor....... This type of fuel cell operates at higher temperature than comparable fuel cell types and they distinguish themselves by high CO tolerance. Platinum based catalysts have their efficiency reduced by CO and the effect is more pronounced at low temperature. This Ph.D. Thesis investigates this type of fuel...

  20. Nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Beauvy, M.; Berthoud, G.; Defranceschi, M.; Ducros, G.; Guerin, Y.; Limoge, Y.; Madic, Ch.; Santarini, G.; Seiler, J.M.; Sollogoub, P.; Vernaz, E.; Guillet, J.L.; Ballagny, A.; Bechade, J.L.; Bonin, B.; Brachet, J.Ch.; Delpech, M.; Dubois, S.; Ferry, C.; Freyss, M.; Gilbon, D.; Grouiller, J.P.; Iracane, D.; Lansiart, S.; Lemoine, P.; Lenain, R.; Marsault, Ph.; Michel, B.; Noirot, J.; Parrat, D.; Pelletier, M.; Perrais, Ch.; Phelip, M.; Pillon, S.; Poinssot, Ch.; Vallory, J.; Valot, C.; Pradel, Ph.; Bonin, B.; Bouquin, B.; Dozol, M.; Lecomte, M.; Vallee, A.; Bazile, F.; Parisot, J.F.; Finot, P.; Roberts, J.F

    2009-07-01

    Fuel is one of the essential components in a reactor. It is within that fuel that nuclear reactions take place, i.e. fission of heavy atoms, uranium and plutonium. Fuel is at the core of the reactor, but equally at the core of the nuclear system as a whole. Fuel design and properties influence reactor behavior, performance, and safety. Even though it only accounts for a small part of the cost per kilowatt-hour of power provided by current nuclear power plants, good utilization of fuel is a major economic issue. Major advances have yet to be achieved, to ensure longer in-reactor dwell-time, thus enabling fuel to yield more energy; and improve ruggedness. Aside from economics, and safety, such strategic issues as use of plutonium, conservation of resources, and nuclear waste management have to be addressed, and true technological challenges arise. This Monograph surveys current knowledge regarding in-reactor behavior, operating limits, and avenues for R and D. It also provides illustrations of ongoing research work, setting out a few noteworthy results recently achieved. Content: 1 - Introduction; 2 - Water reactor fuel: What are the features of water reactor fuel? 9 (What is the purpose of a nuclear fuel?, Ceramic fuel, Fuel rods, PWR fuel assemblies, BWR fuel assemblies); Fabrication of water reactor fuels (Fabrication of UO{sub 2} pellets, Fabrication of MOX (mixed uranium-plutonium oxide) pellets, Fabrication of claddings); In-reactor behavior of UO{sub 2} and MOX fuels (Irradiation conditions during nominal operation, Heat generation, and removal, The processes involved at the start of irradiation, Fission gas behavior, Microstructural changes); Water reactor fuel behavior in loss of tightness conditions (Cladding, the first containment barrier, Causes of failure, Consequences of a failure); Microscopic morphology of fuel ceramic and its evolution under irradiation; Migration and localization of fission products in UOX and MOX matrices (The ceramic under

  1. Investigating the impacts of deep ocean euxinia on continental shelf environments during the Great Ordovician Biodiversification Event: did changes in global oceanic redox have any effect?

    Science.gov (United States)

    Marenco, P. J.; Marenco, K. N.; Phillips, D. E.; Garcia, E.; Toure, N.; Fullem, A.

    2013-12-01

    The Great Ordovician Biodiversification Event was one of the most important radiations in the history of animal life. In particular, the GOBE was characterized by pronounced increases in diversity within the Paleozoic and Modern Evolutionary Faunas (e.g., Droser and Finnegan, 2003). Rather than being attributable to a singular cause, a number of tectonic, ecologic, and climate-related factors are thought to have contributed to this biodiversification event (e.g., Servais et al., 2009). For example, continental shelf area during the GOBE was more extensive than at any other time during the Phanerozoic, and the availability of these warm, shallow-water, well-oxygenated environments likely influenced the radiation (e.g., Servais et al., 2009). Despite this evidence for favorable conditions, recent geochemical studies suggest that the early Paleozoic, including the Ordovician, was a time of episodic deep ocean euxinia (e.g., Gill et al., 2011, Thompson and Kah, 2012). It remains unclear how the hypothesized deep ocean euxinia may have affected the GOBE. For example, it is possible that episodic incursions of euxinic deep water onto the continental shelves may have acted to slow down the GOBE or even dampen its magnitude. On the other hand, such incursions may have accelerated the radiation by adding additional selection pressures to communities that were already adapting to new predation and substrate conditions. Alternatively, the GOBE may have proceeded without any incursions of euxinic deep water onto the continental shelves. One way to address this issue is to investigate short-term, localized redox changes in shallow marine settings. Here we present results from our ongoing investigation of redox changes in shallow-water environments from the Lower and Middle Ordovician of Utah. Specifically, we use abundances of total organic carbon (TOC) and total sulfur (TS) as localized redox proxies. We use the isotopic composition of carbonate associated sulfate (δ34SCAS

  2. An event-related potential investigation of the acute effects of aerobic and coordinative exercise on inhibitory control in children with ADHD

    Directory of Open Access Journals (Sweden)

    Sebastian Ludyga

    2017-12-01

    Full Text Available The current body of evidence suggests that an aerobic exercise session has a beneficial effect on inhibitory control, whereas the impact of coordinative exercise on this executive function has not yet been examined in children with ADHD. Therefore, the present study aims to investigate the acute effects of aerobic and coordinative exercise on behavioral performance and the allocation of attentional resources in an inhibitory control task.Using a cross-over design, children with ADHD-combined type and healthy comparisons completed a Flanker task before and after 20 min moderately-intense cycling exercise, coordinative exercise and an inactive control condition. During the task, stimulus-locked event-related potentials were recorded with electroencephalography.Both groups showed an increase of P300 amplitude and decrease of reaction time after exercise compared to the control condition. Investigating the effect of exercise modality, aerobic exercise led to greater increases of P300 amplitude and reductions in reaction time than coordinative exercise in children with ADHD.The findings suggest that a single exercise bout improves inhibitory control and the allocation of attentional resources. There were some indications that an aerobic exercise session seems to be more efficient than coordinative exercise in reducing the inhibitory control deficits that persist in children with ADHD. Keywords: P300, Executive function, Cognitive performance, Flanker task, Development, Healthy children

  3. Investigation of the role of the micro-porous layer in polymer electrolyte fuel cells with hydrogen deuterium contrast neutron radiography.

    Science.gov (United States)

    Cho, Kyu Taek; Mench, Matthew M

    2012-03-28

    In this study, the high resolution hydrogen-deuterium contrast radiography method was applied to elucidate the impact of the micro-porous layer (MPL) on water distribution in the porous fuel cell media. At the steady state, deuterium replaced hydrogen in the anode stream, and the large difference in neutron attenuation of the D(2)O produced at the cathode was used to track the produced water. It was found that the water content peaked in the cathode-side diffusion media (DM) for the cell without MPL, but with an MPL on the anode and cathode DM, the peak water amount was pushed toward the anode, resulting in a relatively flattened water profile through components and demonstrating a liquid barrier effect. Additionally, the dynamic water behavior in diffusion media was analyzed to understand the effect of a MPL and operating conditions. The water content in the DM changed with applied current, although there is a significant amount of residual liquid content that does not appear to be part of capillary channels. The effect of the MPL on irreducible saturation in DM and cell performance was also investigated.

  4. Nano-nitride cathode catalysts of Ti, Ta, and Nb for polymer electrolyte fuel cells: Temperature-programmed desorption investigation of molecularly adsorbed oxygen at low temperature

    KAUST Repository

    Ohnishi, Ryohji

    2013-01-10

    TiN, NbN, TaN, and Ta3N5 nanoparticles synthesized using mesoporous graphitic (mpg)-C3N4 templates were investigated for the oxygen reduction reaction (ORR) as cathode catalysts for polymer electrolyte fuel cells. The temperature-programmed desorption (TPD) of molecularly adsorbed O2 at 120-170 K from these nanoparticles was examined, and the resulting amount and temperature of desorption were key factors determining the ORR activity. The size-dependent TiN nanoparticles (5-8 and 100 nm) were then examined. With decreasing particle size, the density of molecularly adsorbed O2 per unit of surface area increased, indicating that a decrease in particle size increases the number of active sites. It is hard to determine the electrochemical active surface area for nonmetal electrocatalysts (such as oxides or nitrides), because of the absence of proton adsorption/desorption peaks in the voltammograms. In this study, O2-TPD for molecularly adsorbed O2 at low temperature demonstrated that the amount and strength of adsorbed O2 were key factors determining the ORR activity. The properties of molecularly adsorbed O2 on cathode catalysts are discussed against the ORR activity. © 2012 American Chemical Society.

  5. Investigation of the presence of toxic components of petroleum hydrocarbons in Guanabara Bay, Brazil following the 2000 PETROBRAS fuel oil spill

    Energy Technology Data Exchange (ETDEWEB)

    Romao, Catia Maria [Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renovaveis (IBAMA), Rio de Janeiro, RJ (Brazil). Escritorio de Licenciamento de Petroleo e Nuclear; Vleet, Edward S. Van

    2003-07-01

    On January 18, 2000, approximately 340,000 gallons of marine fuel 380 oil were released into Guanabara Bay, Rio de Janeiro, Brazil, as a consequence of a pipeline transfer accident at the Duque de Caxias Refinery (PETROBRAS). Two years after the spill, the present investigation (sponsored by Center for Disaster Management and Humanitarian Assistance - College of Public Health - University of South Florida) was conducted to assess the levels of Polycyclic Aromatic Hydrocarbons (PAHs) on samples of water, sediments and edible tissue of the fishes (Mullet - Mugilliza and Croaker - Micropogonias furnieri) collected using two types of device (nets and fish traps) from the spill area in July and August 2002. The fishes samples collected in both months were considered to range from being not contaminated to being moderately contaminated by PAHs. Among all the sediments, only one (Point 10, July 2002) showed a total PAH concentration representing highly contaminated conditions. Except for Point 10, all other sediments could be considered minimally to moderately contaminated. Dissolved PAH concentrations found in the water samples were considered to range from minimally to moderately contaminated. (author)

  6. Microscale X-ray tomographic investigation of the interfacial morphology between the catalyst and micro porous layers in proton exchange membrane fuel cells

    Science.gov (United States)

    Prass, Sebastian; Hasanpour, Sadegh; Sow, Pradeep Kumar; Phillion, André B.; Mérida, Walter

    2016-07-01

    The interfacial morphology between the catalyst layer (CL) and micro porous layer (MPL) influences the performance of proton exchange membrane fuel cells (PEMFCs). Here we report a direct method to investigate the CL-MPL interfacial morphology of stacked and compressed gas diffusion layer (GDL with MPL)-catalyst coated membrane (CCM) assemblies. The area, origin and dimensions of interfacial gaps are studied with high-resolution X-ray micro computed tomography (X-μCT). The projected gap area (fraction of the CL-MPL interface separated by gaps) is higher for GDL-CCM assemblies with large differences in the surface roughness between CL and MPL but reduces with increasing compression and similarity in roughness. Relatively large continuous gaps are found in proximity to cracks in the MPL. These are hypothesized to form due to the presence of large pores on the surface of the GDL. Smaller gaps are induced by the surface roughness features throughout the CL-MPL interface. By modification of the pore sizes on the GDL surface serving as substrate for the MPL, the number and dimension of MPL crack induced gaps can be manipulated. Moreover, adjusting the CL and MPL surface roughness parameters to achieve similar orders of roughness can improve the surface mating characteristics of these two components.

  7. Investigation of electrolyte leaching in the performance degradation of phosphoric acid-doped polybenzimidazole membrane-based high temperature fuel cells

    Science.gov (United States)

    Jeong, Yeon Hun; Oh, Kyeongmin; Ahn, Sungha; Kim, Na Young; Byeon, Ayeong; Park, Hee-Young; Lee, So Young; Park, Hyun S.; Yoo, Sung Jong; Jang, Jong Hyun; Kim, Hyoung-Juhn; Ju, Hyunchul; Kim, Jin Young

    2017-09-01

    Precise monitoring of electrolyte leaching in high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) devices during lifetime tests is helpful in making a diagnosis of their quality changes and analyzing their electrochemical performance degradation. Here, we investigate electrolyte leaching in the performance degradation of phosphoric acid (PA)-doped polybenzimidazole (PBI) membrane-based HT-PEMFCs. We first perform quantitative analyses to measure PA leakage during cell operation by spectrophotometric means, and a higher PA leakage rate is detected when the current density is elevated in the cell. Second, long-term degradation tests under various current densities of the cells and electrochemical impedance spectroscopy (EIS) analysis are performed to examine the influence of PA loss on the membrane and electrodes during cell performance degradation. The combined results indicate that PA leakage affect cell performance durability, mostly due to an increase in charge transfer resistance and a decrease in the electrochemical surface area (ECSA) of the electrodes. Additionally, a three-dimensional (3-D) HT-PEMFC model is applied to a real-scale experimental cell, and is successfully validated against the polarization curves measured during various long-term experiments. The simulation results highlight that the PA loss from the cathode catalyst layer (CL) is a significant contributor to overall performance degradation.

  8. Addressing fuel recycling in solid oxide fuel cell systems fed by alternative fuels

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2017-01-01

    An innovative study on anode recirculation in solid oxide fuel cell systems with alternative fuels is carried out and investigated. Alternative fuels under study are ammonia, pure hydrogen, methanol, ethanol, DME and biogas from biomass gasification. It is shown that the amount of anode off-fuel...... recirculation depends strongly on type of the fuel used in the system. Anode recycling combined with fuel cell utilization factors have an important impact on plant efficiency, which will be analysed here. The current study may provide an in-depth understanding of reasons for using anode off-fuel recycling...... and its effect on plant efficiency. For example, it is founded that anode recirculation is not needed when the plant is fed by ammonia. Further, it is founded that when the system is fed by pure hydrogen then anode recirculation should be about 20% of the off-fuel if fuel cell utilization factor is 80...

  9. Small Volume Fuel Testers Report

    Energy Technology Data Exchange (ETDEWEB)

    Schoegl, I. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McNenly, M. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Killingsworth, N. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-31

    Micro-liter fuel ignition testing (μ-FIT) is based on the premise that characteristics FREI (Flames with Repetitive Extinction and Ignition, i.e. cyclically occurring combustion events within heated capillaries), are linked to fuel properties. In early FY16, proof-of-concept measurements with primary reference fuel (PRF) mixtures, i.e. blends of n-heptane and iso-octane, yielded clear evidence for the feasibility of the approach. Our experiments showed that it is critical to accurately link observed flame positions to local temperatures, which provides information on ignition, extinction and flame propagation, all of which are known to be impacted by fuel properties. In FY16, one major hurdle was uncertainty of temperature calibration, which required significant efforts for corrective action that were not included in the original scope of work. Temperature calibrations are obtained by translating a thermocouple within the capillary in absence of a flame. While measurements have good repeatability when accounting for transient and insertion effects, results from nominally identical thermocouples reveal unacceptable uncertainty (up to ±50K), which is attributed to variations in thermocouple placement and manufacturing tolerances. This issue is currently being resolved by switching to non-intrusive optical temperature measurements. Updates are expected to yield uncertainties of less than ±10K, while also eliminating transient and insertion effects. The experimental work was complemented by computational efforts where it was shown that a simplified Lagrangian zero-D model with detailed kinetics yields fuelspecific differentiation of ignition temperatures for simple fuels that are consistent with experiments. Further, a 2D transient model was implemented in OpenFOAM to investigate combustion behavior of simple fuels at elevated pressure. In an upcoming visit to LLNL, more advanced simulations using LLNL’s computational tools (e.g. zero-RK) are planned, which will

  10. Investigation of vegetation-induced drag parameterizations for natural and nature-based extreme events coastal protection in the Chesapeake Bay

    Science.gov (United States)

    Maldonado, S.; Suckale, J.; Ferreira, C.; Arkema, K.

    2016-12-01

    Increasing intensity and frequency of extreme meteorological events around the world highlight the need for resilient coastal defenses. For more than a century, it has been recognized that coastal ecosystems such as marshes and mangroves may mitigate the damage caused by natural hazards such as storms. Aquatic vegetation can potentially attenuate waves and currents through drag forces, with strong implications for sediment transport processes and hence morphological evolution. However, although observations exist that support such a theory, an accurate quantification of the protective role of coastal ecosystems remains a standing challenge for the scientific community, which manifests itself in the large, diverse set of available empirical expressions for parameterizing the fluid-vegetation interaction. We propose a comparison of different state-of-the-art parameterizations for the effect of vegetation on hydrodynamics (particularly, the drag coefficient), with varying degrees of complexity and number of required input variables. The inter-comparison of such alternatives, when validated against field data, can lead to a modeling framework that optimizes the trade-offs between complexity, input requirements and uncertainty in the results. We focus our numerical study on storm events in the marshes and wetlands of Chesapeake Bay. We simulate the hydrodynamics via the Non-Linear Shallow Water Equations, which are in turn solved numerically through a Finite Volume scheme. The simulations are complemented by an ongoing 2-years field campaign, where we continuously collect hydrodynamic measurements such as free surface elevation and vertical velocity profiles, biophysical characteristics of the vegetation and high-resolution topo-bathymetric data of the site. Field measurements are used for calibration and validation purposes. We also investigate some implications on sediment transport processes. We expect that results from our study can support policy makers and

  11. Psychological stress, adverse life events and breast cancer incidence: a cohort investigation in 106,000 women in the United Kingdom.

    Science.gov (United States)

    Schoemaker, Minouk J; Jones, Michael E; Wright, Lauren B; Griffin, James; McFadden, Emily; Ashworth, Alan; Swerdlow, Anthony J

    2016-07-15

    Women diagnosed with breast cancer frequently attribute their cancer to psychological stress, but scientific evidence is inconclusive. We investigated whether experienced frequency of stress and adverse life events affect subsequent breast cancer risk. Breast cancer incidence was analysed with respect to stress variables collected at enrolment in a prospective cohort study of 106,000 women in the United Kingdom, with 1783 incident breast cancer cases. Relative risks (RR) were obtained as hazard ratios using Cox proportional hazards models. There was no association of breast cancer risk overall with experienced frequency of stress. Risk was reduced for death of a close relative during the 5 years preceding study entry (RR = 0.87, 95 % confidence interval (CI): 0.78-0.97), but not for death of a spouse/partner or close friend, personal illness/injury, or divorce/separation. There was a positive association of divorce with oestrogen-receptor-negative (RR = 1.54, 95 % CI: 1.01-2.34), but not with oestrogen-receptor-positive breast cancer. Risk was raised in women who were under age 20 at the death of their mother (RR = 1.31, 95 % CI: 1.02-1.67), but not of their father, and the effect was attenuated after excluding mothers with breast or ovarian cancer (RR = 1.17, 95 % CI: 0.85-1.61). This large prospective study did not show consistent evidence for an association of breast cancer risk with perceived stress levels or adverse life events in the preceding 5 years, or loss of parents during childhood and adolescence.

  12. Analysis and simulation of straw fuel logistics

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Daniel [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Agricultural Engineering

    1998-12-31

    Straw is a renewable biomass that has a considerable potential to be used as fuel in rural districts. This bulky fuel is, however, produced over large areas and must be collected during a limited amount of days and taken to the storages before being ultimately transported to heating plants. Thus, a well thought-out and cost-effective harvesting and handling system is necessary to provide a satisfactory fuel at competitive costs. Moreover, high-quality non-renewable fuels are used in these operations. To be sustainable, the energy content of these fuels should not exceed the energy extracted from the straw. The objective of this study is to analyze straw as fuel in district heating plants with respect to environmental and energy aspects, and to improve the performance and reduce the costs of straw handling. Energy, exergy and emergy analyses were used to assess straw as fuel from an energy point of view. The energy analysis showed that the energy balance is 12:1 when direct and indirect energy requirements are considered. The exergy analysis demonstrated that the conversion step is ineffective, whereas the emergy analysis indicated that large amounts of energy have been used in the past to form the straw fuel (the net emergy yield ratio is 1.1). A dynamic simulation model, called SHAM (Straw HAndling Model), has also been developed to investigate handling of straw from the fields to the plant. The primary aim is to analyze the performance of various machinery chains and management strategies in order to reduce the handling costs and energy needs. The model, which is based on discrete event simulation, takes both weather and geographical conditions into account. The model has been applied to three regions in Sweden (Svaloev, Vara and Enkoeping) in order to investigate the prerequisites for straw harvest at these locations. The simulations showed that straw has the best chances to become a competitive fuel in south Sweden. It was also demonstrated that costs can be

  13. Corrective Action Investigation Plan for Corrective Action Unit 321: Area 22 Weather Station Fuel Storage, Nevada Test Site, Nevada, Revision 0. UPDATED WITH RECORD OF TECHNICAL CHANGE No.1

    Energy Technology Data Exchange (ETDEWEB)

    U.S. DOE/NV

    1999-02-08

    This Corrective Action Investigation Plan (CAIP) has been developed in accordance with the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the US Department of Energy, Nevada Operations Office (DOE/NV); the State of Nevada Division of Environmental Protection (NDEP); and the US Department of Defense (FFACO, 1996). The CAIP is a document that provides or references all of the specific information for investigation activities associated with Corrective Action Units (CAUs) or Corrective Action Sites (CASs). According to the FFACO (1996), CASs are sites potentially requiring corrective action(s) and may include solid waste management units or individual disposal or release sites. A CAU consists of one or more CASs grouped together based on geography, technical similarity, or agency responsibility for the purpose of determining corrective actions. This CAIP contains the environmental sample collection objectives and the criteria for conducting site investigation activities at the CAU 321 Area 22 Weather Station Fuel Storage, CAS 22-99-05 Fuel Storage Area. For purposes of this discussion, this site will be referred to as either CAU 321 or the Fuel Storage Area. The Fuel Storage Area is located in Area 22 of the Nevada Test Site (NTS). The NTS is approximately 105 kilometers (km) (65 miles [mi]) northwest of Las Vegas, Nevada (DOE/NV, 1996a). The Fuel Storage Area was used to store fuel and other petroleum products necessary for motorized operations at the historic Camp Desert Rock facility which was operational from 1951 to 1958 at the Nevada Test Site, Nevada. The site was dismantled after 1958 (DOE/NV, 1996a).

  14. Program of scientific investigations and development of solid-oxide fuel cells (SOFC) in VNIITF. Proposals on scientific and technical collaboration and SOFC commercialization

    Energy Technology Data Exchange (ETDEWEB)

    Kleschev, Yu.N.; Chukharev, V.F.

    1996-04-01

    This paper describes proposals on scientific and technical collaborations pertaining to solid oxide fuel cell commercialization. Topics included for discussion are: materials research and manufacture; market estimation and cost; directions of collaboration; and project of proposals on joint enterprise creation.

  15. Oxy-fuel combustion of solid fuels

    DEFF Research Database (Denmark)

    Toftegaard, Maja Bøg; Brix, Jacob; Jensen, Peter Arendt

    2010-01-01

    Oxy-fuel combustion is suggested as one of the possible, promising technologies for capturing CO2 from power plants. The concept of oxy-fuel combustion is removal of nitrogen from the oxidizer to carry out the combustion process in oxygen and, in most concepts, recycled flue gas to lower the flame...... provide additional options for improvement of process economics are however likewise investigated. Of particular interest is the change of the combustion process induced by the exchange of carbon dioxide and water vapor for nitrogen as diluent. This paper reviews the published knowledge on the oxy......-fuel process and focuses particularly on the combustion fundamentals, i.e. flame temperatures and heat transfer, ignition and burnout, emissions, and fly ash characteristics. Knowledge is currently available regarding both an entire oxy-fuel power plant and the combustion fundamentals. However, several...

  16. An Investigation of Fuel Mixing and Reaction in a CH4/Syngas/Air Premixed Impinging Flame with Varied H2/CO Proportion

    Directory of Open Access Journals (Sweden)

    Chih-Pin Chiu

    2017-07-01

    Full Text Available For industrial applications, we propose a concept of clean and efficient combustion through burning syngas on an impinging burner. We performed experimental measurements of particle image velocimetry, OH radical (OH* chemiluminescence, flame temperature, and CO emission to examine the fuel mixing and reaction of premixed impinging flames of CH4/syngas/air with H2/CO in varied proportions. The velocity distribution of the combustion flow field showed that a deceleration area in the main flow formed through the mutual impingement of two jet flows, which enhanced the mixing of fuel and air because of an increased momentum transfer. The deceleration area expanded with an increased CO proportion, which indicated that the mixing of fuel and air also increased with the increased CO proportion. Our examination of the OH* chemiluminescence demonstrated that its intensity increased with increased CO proportion, which showed that the reaction between fuel and air accordingly increased. CO provided in the syngas hence participated readily in the reaction of the CH4/syngas/air premixed impinging flames when the syngas contained CO in a large proportion. Although the volume flow rate of the provided CO quadrupled, the CO emission increased by only 12% to 15%. The results of this work are useful to improve the feasibility of fuel-injection systems using syngas as an alternative fuel.

  17. FAILED FUEL DISPOSITION STUDY

    Energy Technology Data Exchange (ETDEWEB)

    THIELGES, J.R.

    2004-12-20

    In May 2004 alpha contamination was found on the lid of the pre-filter housing in the Sodium Removal Ion Exchange System during routine filter change. Subsequent investigation determined that the alpha contamination likely came from a fuel pin(s) contained in an Ident-69 (ID-69) type pin storage container serial number 9 (ID-69-9) that was washed in the Sodium Removal System (SRS) in January 2004. Because all evidence indicated that the wash water interacted with the fuel, this ID49 is designated as containing a failed fuel pin with gross cladding defect and was set aside in the Interim Examination and Maintenance (IEM) Cell until it could be determined how to proceed for long term dry storage of the fuel pin container. This ID49 contained fuel pins from the driver fuel assembly (DFA) 16392, which was identified as a Delayed Neutron Monitor (DNM) leaker assembly. However, this DFA was disassembled and the fuel pin that was thought to be the failed pin was encapsulated and was not located in this ID49 container. This failed fuel disposition study discusses two alternatives that could be used to address long term storage for the contents of ID-69-9. The first alternative evaluated utilizes the current method of identifying and storing DNM leaker fuel pin(s) in tubes and thus, verifying that the alpha contamination found in the SRS came from a failed pin in this pin container. This approach will require unloading selected fuel pins from the ID-69, visually examining and possibly weighing suspect fuel pins to identify the failed pin(s), inserting the failed pin(s) in storage tubes, and reloading the fuel pins into ID49 containers. Safety analysis must be performed to revise the 200 Area Interim Storage Area (ISA) Final Safety Analysis Report (FSAR) (Reference 1) for this fuel configuration. The second alternative considered is to store the failed fuel as-is in the ID-69. This was evaluated to determine if this approach would comply with storage requirements. This

  18. Fossil Fuels.

    Science.gov (United States)

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with fossil fuels. Some topics covered are historic facts, development of fuels, history of oil production, current and future trends of the oil industry, refining fossil fuels, and environmental problems. Material in each unit may…

  19. Multi-physics modelling contributions to investigate the atmospheric cosmic rays on the single event upset sensitivity along the scaling trend of CMOS technologies.

    Science.gov (United States)

    Hubert, G; Regis, D; Cheminet, A; Gatti, M; Lacoste, V

    2014-10-01

    Particles originating from primary cosmic radiation, which hit the Earth's atmosphere give rise to a complex field of secondary particles. These particles include neutrons, protons, muons, pions, etc. Since the 1980s it has been known that terrestrial cosmic rays can penetrate the natural shielding of buildings, equipment and circuit package and induce soft errors in integrated circuits. Recently, research has shown that commercial static random access memories are now so small and sufficiently sensitive that single event upsets (SEUs) may be induced from the electronic stopping of a proton. With continued advancements in process size, this downward trend in sensitivity is expected to continue. Then, muon soft errors have been predicted for nano-electronics. This paper describes the effects in the specific cases such as neutron-, proton- and muon-induced SEU observed in complementary metal-oxide semiconductor. The results will allow investigating the technology node sensitivity along the scaling trend. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Deficits in inhibitory control in smokers during a Go/NoGo task: an investigation using event-related brain potentials.

    Directory of Open Access Journals (Sweden)

    Maartje Luijten

    Full Text Available INTRODUCTION: The role of inhibitory control in addictive behaviors is highlighted in several models of addictive behaviors. Although reduced inhibitory control has been observed in addictive behaviors, it is inconclusive whether this is evident in smokers. Furthermore, it has been proposed that drug abuse individuals with poor response inhibition may experience greater difficulties not consuming substances in the presence of drug cues. The major aim of the current study was to provide electrophysiological evidence for reduced inhibitory control in smokers and to investigate whether this is more pronounced during smoking cue exposure. METHODS: Participants (19 smokers and 20 non-smoking controls performed a smoking Go/NoGo task. Behavioral accuracy and amplitudes of the N2 and P3 event-related potential (ERP, both reflecting aspects of response inhibition, were the main variables of interest. RESULTS: Reduced NoGo N2 amplitudes in smokers relative to controls were accompanied by decreased task performance, whereas no differences between groups were found in P3 amplitudes. This was found to represent a general lack of inhibition in smokers, and not dependent on the presence of smoking cues. CONCLUSIONS: The current results suggest that smokers have difficulties with response inhibition, which is an important finding that eventually can be implemented in smoking cessation programs. More research is needed to clarify the exact role of cue exposure on response inhibition.

  1. The P300 event-related brain potential as a neurobiological endophenotype for substance use disorders: a meta-analytic investigation.

    Science.gov (United States)

    Euser, Anja S; Arends, Lidia R; Evans, Brittany E; Greaves-Lord, Kirstin; Huizink, Anja C; Franken, Ingmar H A

    2012-01-01

    Endophenotypes are intermediate phenotypes on the putative causal pathway from genotype to phenotype and can aid in discovering the genetic etiology of a disorder. There are currently very few suitable endophenotypes available for substance use disorders (SUD). The amplitude of the P300 event-related brain potential is a possible candidate. The present study determined whether the P300 amplitude fulfils two fundamental criteria for an endophenotype: (1) an association with the disorder (disease marker), and (2) presence in unaffected biological relatives of those who have the disorder (vulnerability marker). For this purpose, two separate meta-analyses were performed. Meta-analysis 1 investigated the P300 amplitude in relation to SUD in 39 studies and Meta-analysis 2 investigated P300 amplitude in relation to a family history (FH+) of SUD in 35 studies. The findings indicate that a reduced P300 amplitude is significantly associated with SUD (d=0.51) and, though to a lesser extent, with a FH+ of SUD (d=0.28). As a disease maker, the association between reduced P300 amplitude and SUD is significantly larger for participants that were exclusively recruited from treatment facilities (d=0.67) than by other methods (i.e., community samples and family studies; d=0.45 and 0.32, respectively), and larger for abstinent SUD patients (d=0.71) than for current substance users (d=0.37). Furthermore, in contrast to FH+ males, a P300 amplitude reduction seems not to be present in FH+ females (d=-0.07). Taken together, these results suggest that P300 amplitude reduction can be both a useful disease and vulnerability marker and is a promising neurobiological endophenotype for SUD, though only in males. Implications and future directions are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Investigation of a methanol reformer concept considering the particular impact of dynamics and long-term stability for use in a fuel-cell-powered passenger car

    Science.gov (United States)

    Peters, R.; Düsterwald, H. G.; Höhlein, B.

    A methanol reformer concept including a reformer, a catalytic burner, a gas cleaning unit, a PEMFC and an electric motor for use in fuel-cell-powered passenger cars was investigated. Special emphasis was placed on the dynamics and the long-term stability of the reformer. Experiments on a laboratory scale were performed in a methanol steam reformer consisting of four different reactor tubes, which were separately balanced. Due to the endothermy of the steam reforming reaction of methanol, a sharp drop in the reaction temperature of about 50 K occurs at the beginning of the catalyst bed. This agrees well with the high catalytic activity at the entrance of the catalyst bed. Forty-five percent of the methanol was converted within the first 10 cm of the catalyst bed where 12.6 g of the CuO/ZnO catalyst was located. Furthermore, CO formation during methanol steam reforming strongly depends on methanol conversion. Long-term measurements for more than 700 h show that the active reaction zone moved through the catalyst bed. Calculations, on the basis of these experiments, revealed that 63 g of reforming catalyst was necessary for mobile PEMFC applications, in this case for 400 W el at a system efficiency of 42% and a theoretical specific hydrogen production of 5.2 m 3n/(h kg Cat). This amount of catalyst was assumed to maintain a hydrogen production of at least 80% of the original amount over an operating range of 3864 h. Cycled start-up and shut-down processes of the methanol steam reformer under nitrogen and hydrogen atmospheres did not harm the catalytic activity. The simulation of the breakdown of the heating system, in which a liquid water/methanol mixture was in close contact with the catalyst, did not reveal any deactivation of the catalytic activity.

  3. Understanding the complexation of Eu3 + with potential ligands used for preferential separation of lanthanides and actinides in various stages of nuclear fuel cycle: A luminescence investigation

    Science.gov (United States)

    Sengupta, Arijit; Kadam, R. M.

    2017-02-01

    A systematic photoluminescence based investigation was carried out to understand the complexation of Eu3 + with different ligands (TBP: tri-n-butyl phosphate, DHOA: di-n-hexyl octanamide, Cyanex 923: tri-n-alkyl phosphine oxide and Cyanex 272: Bis (2,4,4 trimethyl) pentyl phosphinic acid) used for preferential separation of lanthanides and actinides in various stages of nuclear fuel cycle. In case of TBP and DHOA complexes, 3 ligand molecules coordinated in monodentate fashion and 3 nitrate ion in bidentate fashion to Eu3 + to satisfy the 9 coordination of Eu. In case of Cyanex 923 and Cyanex 272 complexes, 3 ligand molecules, 3 nitrate ion and 3 water molecules coordinated to Eu3 + in monodentate fashion. The Eu complexes of TBP and DHOA were found to have D3h local symmetry while that for Cyanex 923 and Cyanex 272 were C3h. Judd-Ofelt analysis of these systems revealed that the covalency of Eusbnd O bond followed the trend DHOA > TBP > Cyanex 272 > Cyanex 923. Different photophysical properties like radiative and non-radiative life time, branching ratio for different transitions, magnetic and electric dipole moment transition probabilities and quantum efficiency were also evaluated and compared for these systems. The magnetic dipole transition probability was found to be almost independent of ligand field perturbation while electric dipole transition probability for 5D0-7F2 transition was found to be hypersensitive with ligand field with a trend DHOA > TBP > Cyanex 272 > Cyanex 923. Supplementary Table 2: Determination of inner sphere water molecules from the different empirical formulae reported in the literature.

  4. The onset of childhood amnesia in childhood: a prospective investigation of the course and determinants of forgetting of early-life events.

    Science.gov (United States)

    Bauer, Patricia J; Larkina, Marina

    2014-01-01

    The present research was an examination of the onset of childhood amnesia and how it relates to maternal narrative style, an important determinant of autobiographical memory development. Children and their mothers discussed unique events when the children were 3 years of age. Different subgroups of children were tested for recall of the events at ages 5, 6, 7, 8, and 9 years. At the later session they were interviewed by an experimenter about the events discussed 2 to 6 years previously with their mothers (early-life events). Children aged 5, 6, and 7 remembered 60% or more of the early-life events. In contrast, children aged 8 and 9 years remembered fewer than 40% of the early-life events. Overall maternal narrative style predicted children's contributions to mother-child conversations at age 3 years; it did not have cross-lagged relations to memory for early-life events at ages 5 to 9 years. Maternal deflections of the conversational turn to the child predicted the amount of information children later reported about the early-life events. The findings have implications for our understanding of the onset of childhood amnesia and the achievement of an adult-like distribution of memories in the school years. They highlight the importance of forgetting processes in explanations of the amnesia.

  5. Myocardial perfusion imaging for predicting cardiac events in Japanese patients with advanced chronic kidney disease: 1-year interim report of the J-ACCESS 3 investigation

    Energy Technology Data Exchange (ETDEWEB)

    Joki, Nobuhiko; Hase, Hiroki [Toho University Ohashi Medical Center, Department of Nephrology, Tokyo (Japan); Kawano, Yuhei; Nakamura, Satoko [National Cerebral and Cardiovascular Center, Division of Hypertension and Nephrology, Osaka (Japan); Nakajima, Kenichi [Kanazawa University Hospital, Department of Nuclear Medicine, Kanazawa (Japan); Hatta, Tsuguru [Hatta Medical Office of Internal Medicine, Kyoto (Japan); Nishimura, Shigeyuki [Saitama Medical University International Medical Center, Saitama (Japan); Moroi, Masao [Toho University Ohashi Medical Center, Department of Cardiology, Tokyo (Japan); Nakagawa, Susumu [Saiseikai Central Hospital, Department of Cardiology, Tokyo (Japan); Kasai, Tokuo [Tokyo Medical University Hachioji Medical Center, Tokyo (Japan); Kusuoka, Hideo [Osaka National Hospital, Osaka (Japan); Takeishi, Yasuchika [Fukushima Medical University, Department of Cardiology and Hematology, Fukushima (Japan); Momose, Mitsuru [Tokyo Women' s Medical University, Department of Diagnostic Imaging and Nuclear Medicine, Tokyo (Japan); Takehana, Kazuya [Kansai Medical University, Department of Cardiology, Osaka (Japan); Nanasato, Mamoru [Cardiovascular Center, Nagoya Daini Red Cross Hospital, Nagoya (Japan); Yoda, Shunichi [Nihon University Itabashi Hospital, Department of Cardiology, Tokyo (Japan); Nishina, Hidetaka [Tsukuba Medical Center Hospital, Department of Cardiology, Tsukuba (Japan); Matsumoto, Naoya [Suruga-dai Nihon University Hospital, Department of Cardiology, Tokyo (Japan); Nishimura, Tsunehiko [Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto (Japan)

    2014-09-15

    Whether myocardial perfusion imaging (MPI) can predict cardiac events in patients with advanced conservative chronic kidney disease (CKD) remains unclear. The present multicenter prospective cohort study aimed to clarify the ability of MPI to predict cardiac events in 529 patients with CKD and estimated glomerular filtration rates (eGFR) < 50 ml/min per 1.73{sup 2} without a definitive diagnosis of coronary artery disease. All patients were assessed by stress-rest MPI with {sup 99m}Tc-tetrofosmin and analyzed using summed defect scores and QGS software. Cardiac events were analyzed 1 year after registration. Myocardial perfusion abnormalities defined as summed stress score (SSS) ≥4 and ≥8 were identified in 19 and 7 % of patients, respectively. At the end of the 1-year follow-up, 33 (6.2 %) cardiac events had occurred that included cardiac death, sudden death, nonfatal myocardial infarction, and hospitalization due to heart failure. The event-free rates at that time were 0.95, 0.90, and 0.81 for groups with SSS 0-3, 4-7, and ≥8, respectively (p = 0.0009). Thus, patients with abnormal SSS had a higher incidence of cardiac events. Multivariate Cox regression analysis showed that SSS significantly impacts the prediction of cardiac events independently of eGFR and left ventricular ejection fraction. MPI would be useful to stratify patients with advanced conservative CKD who are at high risk of cardiac events without adversely affecting damaged kidneys. (orig.)

  6. Talking about Real-Life Events: An Investigation into the Ability of People with Intellectual Disabilities to Make Links between Their Beliefs and Emotions within Dialogue

    Science.gov (United States)

    Hebblethwaite, Amy; Jahoda, Andrew; Dagnan, Dave

    2011-01-01

    Background: This study compares how people with and without intellectual disabilities talk about events, beliefs and emotions in dialogues about real-life, emotive events and in a structured task assessing understanding of cognitive mediation. Materials and Methods: A cognitive-emotive interview was used to assist 19 adults with intellectual…

  7. Reports of Perceived Adverse Events of Stimulant Medication on Cognition, Motivation, and Mood: Qualitative Investigation and the Generation of Items for the Medication and Cognition Rating Scale

    NARCIS (Netherlands)

    Kovshoff, H.; Banaschewski, T.; Buitelaar, J.K.; Carucci, S.; Coghill, D.; Danckaerts, M.; Dittmann, R.W.; Falissard, B.; Grimshaw, D.G.; Hollis, C.; Inglis, S.; Konrad, K.; Liddle, E.; McCarthy, S.; Nagy, P.; Thompson, M.; Wong, I.C.; Zuddas, A.; Sonuga-Barke, E.J.

    2016-01-01

    OBJECTIVE: There is no questionnaire to specifically monitor perceived adverse events of methylphenidate (MPH) on cognition, motivation, and mood. The current study therefore had two goals. First, to harvest accounts of such putative events from transcripts of interviews in samples enriched for such

  8. Fuel distribution

    Energy Technology Data Exchange (ETDEWEB)

    Tison, R.R.; Baker, N.R.; Blazek, C.F.

    1979-07-01

    Distribution of fuel is considered from a supply point to the secondary conversion sites and ultimate end users. All distribution is intracity with the maximum distance between the supply point and end-use site generally considered to be 15 mi. The fuels discussed are: coal or coal-like solids, methanol, No. 2 fuel oil, No. 6 fuel oil, high-Btu gas, medium-Btu gas, and low-Btu gas. Although the fuel state, i.e., gas, liquid, etc., can have a major impact on the distribution system, the source of these fuels (e.g., naturally-occurring or coal-derived) does not. Single-source, single-termination point and single-source, multi-termination point systems for liquid, gaseous, and solid fuel distribution are considered. Transport modes and the fuels associated with each mode are: by truck - coal, methanol, No. 2 fuel oil, and No. 6 fuel oil; and by pipeline - coal, methane, No. 2 fuel oil, No. 6 oil, high-Btu gas, medium-Btu gas, and low-Btu gas. Data provided for each distribution system include component makeup and initial costs.

  9. Checklist for transition to new highway fuel(s).

    Energy Technology Data Exchange (ETDEWEB)

    Risch, C.; Santini, D.J. (Energy Systems)

    2011-12-15

    Transportation is vital to the U.S. economy and society. As such, U.S. Presidents have repeatedly stated that the nation needs to reduce dependence on petroleum, especially for the highway transportation sector. Throughout history, highway transportation fuel transitions have been completed successfully both in United States and abroad. Other attempts have failed, as described in Appendix A: Historical Highway Fuel Transitions. Planning for a transition is critical because the changes can affect our nation's ability to compete in the world market. A transition will take many years to complete. While it is tempting to make quick decisions about the new fuel(s) of choice, it is preferable and necessary to analyze all the pertinent criteria to ensure that correct decisions are made. Doing so will reduce the number of changes in highway fuel(s). Obviously, changes may become necessary because of occurrences such as significant technology breakthroughs or major world events. With any and all of the possible transitions to new fuel(s), the total replacement of gasoline and diesel fuels is not expected. These conventional fuels are envisioned to coexist with the new fuel(s) for decades, while the revised fuel and vehicle infrastructures are implemented. The transition process must analyze the needs of the primary 'players,' which consist of the customers, the government, the fuel industry, and the automotive industry. To maximize the probability of future successes, the prime considerations of these groups must be addressed. Section 2 presents a succinct outline of the Checklist. Section 3 provides a brief discussion about the groupings on the Checklist.

  10. Heterogeneous UO{sub 2} fuel irradiated up to a high burn-up: Investigation of the HBS and of fission product releases

    Energy Technology Data Exchange (ETDEWEB)

    Noirot, J., E-mail: jean.noirot@cea.fr [CEA, DEN, DEC, Cadarache, F-13108 St. Paul Lez Durance (France); Lamontagne, J. [CEA, DEN, DEC, Cadarache, F-13108 St. Paul Lez Durance (France); Nakae, N. [JNES, Toranomon Towers Office, 4-1-28, Toranomon, Minato-ku, Tokyo 105-0001 (Japan); Kitagawa, T. [MNF, 622-1 Funaishikawa, Tokai-mura, Naka-gun, Ibaraki 319-1197 (Japan); Kosaka, Y. [NDC, 622-12 Funaishikawa, Tokai-mura, Ibaraki 319-1111 (Japan); Tverberg, T. [IFE, P.O. Box 173, NO-1751 Halden (Norway)

    2013-11-15

    A UO{sub 2} fuel with a heterogeneous distribution of {sup 235}U was irradiated up to a high burn-up in the Halden Boiling Water Reactor (HBWR). The last 100 days of irradiation were performed with an increased level of linear power. The effect of the heterogeneous fissile isotope distribution on the formation of the HBS was studied free of the possible influence of Pu which exists in heterogeneous MOX fuels. The HBS formed in {sup 235}U-rich agglomerates and its main characteristics were very similar to those of the HBS formed in Pu-rich agglomerates of heterogeneous MOX fuels. The maximum local contents of Nd and Xe before HBS formation were studied in this fuel. In addition to a Pu effect that promotes the HBS phenomenon, comparison with previous results for heterogeneous MOX fuels showed that the local fission product concentration was not the only parameter that has to be taken into consideration. It appears that the local actinide depletion by fission and/or the energy locally deposited through electronic interactions in the fission fragment recoils also have an effect on the HBS formation threshold. Moreover, a major release of fission gases from the peripheral {sup 235}U-rich agglomerates of HBS bubbles and a Cs radial movement are also evidenced in this heterogeneous UO{sub 2}. Cs deposits on the peripheral grain boundaries, including the HBS grain boundaries, are considered to reveal the release paths.

  11. Experimental investigation of hydraulic effects of two-stage fuel injection on fuel-injection systems and diesel combustion in a high-speed optical common-rail diesel engine

    OpenAIRE

    Herfatmanesh, MR; Zhao, H

    2014-01-01

    In order to meet the ever more stringent emission standards, significant efforts have been devoted to the research and development of internal combustion engines. The requirements for more efficient and responsive diesel engines have led to the introduction and implementation of multiple injection strategies. However, the effects of such injection modes on the hydraulic systems, such as the high-pressure pipes and fuel injectors, must be thoroughly examined and compensated for since the combu...

  12. Investigation into the effects of trace coal syn gas species on the performance of solid oxide fuel cell anodes, PhD. thesis, Russ College of Engineering and Technology of Ohio University

    Energy Technology Data Exchange (ETDEWEB)

    Trembly, Jason P. [Ohio Univ., Athens, OH (United States). Russ College of Engineering and Technology

    2007-06-01

    Coal is the United States’ most widely used fossil fuel for the production of electric power. Coal’s availability and cost dictates that it will be used for many years to come in the United States for power production. As a result of the environmental impact of burning coal for power production more efficient and environmentally benign power production processes using coal are sought. Solid oxide fuel cells (SOFCs) combined with gasification technologies represent a potential methodology to produce electric power using coal in a much more efficient and cleaner manner. It has been shown in the past that trace species contained in coal, such as sulfur, severely degrade the performance of solid oxide fuel cells rendering them useless. Coal derived syngas cleanup technologies have been developed that efficiently remove sulfur to levels that do not cause any performance losses in solid oxide fuel cells. The ability of these systems to clean other trace species contained in syngas is not known nor is the effect of these trace species on the performance of solid oxide fuel cells. This works presents the thermodynamic and diffusion transport simulations that were combined with experimental testing to evaluate the effects of the trace species on the performance of solid oxide fuel cells. The results show that some trace species contained in coal will interact with the SOFC anode. In addition to the transport and thermodynamic simulations that were completed experimental tests were completed investigating the effect of HCl and AsH3 on the performance of SOFCs.

  13. Seismicity and tectonic tremor accompany the 2014 Gisborne Slow Slip Event: Insights from the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip (HOBITSS) Experiment, New Zealand

    Science.gov (United States)

    Todd, E. K.; Schwartz, S. Y.; Sheehan, A. F.; Mochizuki, K.

    2016-12-01

    The northern Hikurangi Margin is host to some of the shallowest slow slip events (SSEs) in the world. Slow slip offshore Gisborne, New Zealand has been observed at depths as shallow as 2 km and may extend all the way to the trench. Gisborne SSEs are accompanied by tectonic tremor and increased levels of seismicity, but this activity has only been observed at the onshore, downdip edge of the slow slip patch. Between May 2014 and June 2015, 24 absolute pressure gauges, 10 broadband seismometers, and 5 short period seismometers were deployed offshore Gisborne along the east coast of the North Island of New Zealand as part of the HOBITSS Experiment. These instruments were in place during a large Gisborne SSE (peak slip 20 cm) in September and October 2014. Using this new ocean-derived dataset in conjunction with existing land data from the New Zealand National Seismograph Network operated by GeoNet (http://geonet.org.nz), we present an in-depth, systematic investigation of tremor and microseismicity associated with this shallow Gisborne SSE to further examine the spatial heterogeneity of slip processes on the shallow megathrust. Tremor and earthquakes are collocated with the geodetically inverted slow slip patch with tremor occurring offshore and earthquakes concentrated downdip of a shallowly subducted seamount near the region of peak displacement during the SSE. This discovery indicates that the region of the megathrust slipping in these SSEs is capable of multiple types of slip and understanding the spatiotemporal relationships between these strain release modes has implications for local seismic hazards.

  14. Investigating the role of temporal lobe activation in speech perception accuracy with normal hearing adults: An event-related fNIRS study.

    Science.gov (United States)

    Defenderfer, Jessica; Kerr-German, Anastasia; Hedrick, Mark; Buss, Aaron T

    2017-11-01

    Functional near infrared spectroscopy (fNIRS) is a safe, non-invasive, relatively quiet imaging technique that is tolerant of movement artifact making it uniquely ideal for the assessment of hearing mechanisms. Previous research demonstrates the capacity for fNIRS to detect cortical changes to varying speech intelligibility, revealing a positive relationship between cortical activation amplitude and speech perception score. In the present study, we use an event-related design to investigate the hemodynamic response in the temporal lobe across different listening conditions. We presented participants with a speech recognition task using sentences in quiet, sentences in noise, and vocoded sentences. Hemodynamic responses were examined across conditions and then compared when speech perception was accurate compared to when speech perception was inaccurate in the context of noisy speech. Repeated measures, two-way ANOVAs revealed that the speech in noise condition (-2.8dB signal-to-noise ratio/SNR) demonstrated significantly greater activation than the easier listening conditions on multiple channels bilaterally. Further analyses comparing correct recognition trials to incorrect recognition trials (during the presentation phase of the trial) revealed that activation was significantly greater during correct trials. Lastly, during the repetition phase of the trial, where participants correctly repeated the sentence, the hemodynamic response demonstrated significantly higher deoxyhemoglobin than oxyhemoglobin, indicating a difference between the effects of perception and production on the cortical response. Using fNIRS, the present study adds meaningful evidence to the body of knowledge that describes the brain/behavior relationship related to speech perception. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Investigation of boundary-layer wind predictions during nocturnal low-level jet events using the Weather Research and Forecasting model

    Energy Technology Data Exchange (ETDEWEB)

    Mirocha, Jeff D.; Simpson, Matthew D.; Fast, Jerome D.; Berg, Larry K.; Baskett, R.

    2016-04-01

    Simulations of two periods featuring three consecutive low level jet (LLJ) events in the US Upper Great Plains during the autumn of 2011 were conducted to explore the impacts of various setup configurations and physical process models on simulated flow parameters within the lowest 200 m above the surface, using the Weather Research and Forecasting (WRF) model. Sensitivities of simulated flow parameters to the horizontal and vertical grid spacing, planetary boundary layer (PBL) and land surface model (LSM) physics options, were assessed. Data from a Light Detection and Ranging (lidar) system, deployed to the Weather Forecast Improvement Project (WFIP; Finley et al. 2013) were used to evaluate the accuracy of simulated wind speed and direction at 80 m above the surface, as well as their vertical distributions between 120 and 40 m, covering the typical span of contemporary tall wind turbines. All of the simulations qualitatively captured the overall diurnal cycle of wind speed and stratification, producing LLJs during each overnight period, however large discrepancies occurred at certain times for each simulation in relation to the observations. 54-member ensembles encompassing changes of the above discussed configuration parameters displayed a wide range of simulated vertical distributions of wind speed and direction, and potential temperature, reflecting highly variable representations of stratification during the weakly stable overnight conditions. Root mean square error (RMSE) statistics show that different ensemble members performed better and worse in various simulated parameters at different times, with no clearly superior configuration . Simulations using a PBL parameterization designed specifically for the stable conditions investigated herein provided superior overall simulations of wind speed at 80 m, demonstrating the efficacy of targeting improvements of physical process models in areas of known deficiencies. However, the considerable magnitudes of the

  16. The processing of number and gender agreement in Spanish: an event-related potential investigation of the effects of structural distance.

    Science.gov (United States)

    Alemán Bañón, José; Fiorentino, Robert; Gabriele, Alison

    2012-05-25

    Previous research suggests that the processing of agreement is affected by the distance between the agreeing elements. However, the unique contribution of structural distance (number of intervening syntactic phrases) to the processing of agreement remains an open question, since previous investigations do not tease apart structural and linear distance (number of intervening words). We used event-related potentials (ERPs) to examine the extent to which structural distance impacts the processing of Spanish number and gender agreement. Violations were realized both within the phrase and across the phrase. Across both levels of structural distance, linear distance was kept constant, as was the syntactic category of the agreeing elements. Number and gender agreement violations elicited a robust P600 between 400 and 900 ms, a component associated with morphosyntactic processing. No amplitude differences were observed between number and gender violations, suggesting that the two features are processed similarly at the brain level. Within-phrase agreement yielded more positive waveforms than across-phrase agreement, both for agreement violations and for grammatical sentences (no agreement by distance interaction). These effects can be interpreted as evidence that structural distance impacts the establishment of agreement overall, consistent with sentence processing models which predict that hierarchical structure impacts the processing of syntactic dependencies. However, due to the lack of an agreement by distance interaction, the possibility cannot be ruled out that these effects are driven by differences in syntactic predictability between the within-phrase and across-phrase configurations, notably the fact that the syntactic category of the critical word was more predictable in the within-phrase conditions. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Motor fuel prices in Turkey

    OpenAIRE

    Erdogdu, Erkan

    2013-01-01

    The world’s most expensive motor fuel (gasoline, diesel and LPG) is sold most likely in the Republic of Turkey. This paper investigates the key issues related to the motor fuel prices in Turkey. First of all, the paper analyses the main reason behind high prices, namely motor fuel taxes in Turkey. Then, it estimates the elasticity of motor fuel demand in Turkey using an econometric analysis. The findings indicate that motor fuel demand in Turkey is quite inelastic and, therefore, not responsi...

  18. Accident tolerant composite nuclear fuels

    Directory of Open Access Journals (Sweden)

    Szpunar Barbara

    2017-01-01

    Full Text Available Investigated accident tolerant nuclear fuels are fuels with enhanced thermal conductivity, which can withstand the loss of coolant for a longer time by allowing faster dissipation of heat, thus lowering the centerline temperature and preventing the melting of the fuel. Traditional nuclear fuels have a very low thermal conductivity and can be significantly enhanced if transformed into a composite with a very high thermal conductivity components. In this study, we analyze the thermal properties of various composites of mixed oxides and thoria fuels to improve thermal conductivity for the next generation safer nuclear reactors.

  19. Investigation of economics of back-end nuclear fuel cycle options in the Republic of Korea based on Once-through

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seok-Ki; Yim, Man-Sung [Korea Advance Institute of Science and Technology, Daejeon (Korea, Republic of)

    2015-05-15

    The purpose of this study is to examine these questions and perform economic evaluations of various cases of Once-through back-end fuel cycles in the ROK. Therefore, the study is to support decision making in terms of how the long term spent nuclear fuel (SNF) management strategy should be developed. A spreadsheet model was developed to plan reactor construction, the interim storage and the HLW repository construction within engineered constraints, based on the estimation of the spent fuel flow and the energy supply of the nuclear power program. The model computes the back-end levelized costs for various fuel cycle choices. The scenarios assumed in the model include (1) 0 year/10year/20year of licensed operation period extension; (2) the phase-out of NPP program and the continuous use including the reunification of Korean peninsula; (3) reactor decommissioning and construction lead times - 10 years and 5 years respectively in this study; (4) geological constraints of siting for a new reactor - 38 for without the reunification and 70 for with the reunification; (5) the first initiation of reactor decommissioning and operation of HLW repository - assumed to be 2020 and 2050; and (6) capacity factor of reactor operation and the on-site wet storage pool capacity - 0.85 and 0.498 MTHM per MWe which is equivalent with APR1400. The capacity factor for PHWR reactors was assumed at 0.85 and the plan for PHWR was fixed as phase-out. The spreadsheet model conducts computation for annual expenditures of the back-end fuel cycle and calculates the levelized costs. Licensed operation period extension enhances not only economic efficiency, stable energy supply, but also reduces burden of siting for a new reactor and waste disposal. And regardless the reunification, continuous use of nuclear energy lowers the back-end fuel cycle cost. With projection that a large portion of social cost is included in the current back-end fuel cycle cost, nuclear energy likely has more competency in

  20. Structure and Dynamics of Fuel Jets Injected into a High-Temperature Subsonic Crossflow: High-Data-Rate Laser Diagnostic Investigation under Steady and Oscillatory Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lucht, Robert [Purdue Univ., West Lafayette, IN (United States); Anderson, William [Purdue Univ., West Lafayette, IN (United States)

    2015-01-23

    An investigation of subsonic transverse jet injection into a subsonic vitiated crossflow is discussed. The reacting jet in crossflow (RJIC) system investigated as a means of secondary injection of fuel in a staged combustion system. The measurements were performed in test rigs featuring (a) a steady, swirling crossflow and (b) a crossflow with low swirl but significant oscillation in the pressure field and in the axial velocity. The rigs are referred to as the steady state rig and the instability rig. Rapid mixing and chemical reaction in the near field of the jet injection is desirable in this application. Temporally resolved velocity measurements within the wake of the reactive jets using 2D-PIV and OH-PLIF at a repetition rate of 5 kHz were performed on the RJIC flow field in a steady state water-cooled test rig. The reactive jets were injected through an extended nozzle into the crossflow which is located in the downstream of a low swirl burner (LSB) that produced the swirled, vitiated crossflow. Both H2/N2 and natural gas (NG)/air jets were investigated. OH-PLIF measurements along the jet trajectory show that the auto-ignition starts on the leeward side within the wake region of the jet flame. The measurements show that jet flame is stabilized in the wake of the jet and wake vortices play a significant role in this process. PIV and OH–PLIF measurements were performed at five measurement planes along the cross- section of the jet. The time resolved measurements provided significant information on the evolution of complex flow structures and highly transient features like, local extinction, re-ignition, vortex-flame interaction prevalent in a turbulent reacting flow. Nanosecond-laser-based, single-laser-shot coherent anti-Stokes Raman scattering (CARS) measurements of temperature and H2 concentraiton were also performed. The structure and dynamics of a reacting transverse jet injected into a vitiated oscillatory crossflow presents a unique opportunity for

  1. Putting the relationship between social anxiety and alcohol use into context: A daily diary investigation of drinking in response to embarrassing events

    OpenAIRE

    O’Grady, Megan A.; Cullum, Jerry; Armeli, Stephen; Tennen, Howard

    2011-01-01

    The goal of this study was to clarify mixed findings regarding the association between dispositional social anxiety and drinking among college students by using a daily diary method to examine whether a within-person social-contextual event moderated the relationship between social anxiety and alcohol use. College students (n = 476) completed a measure of dispositional social anxiety and then for 30 days reported whether they experienced an embarrassing event in public and the amount of alcoh...

  2. Case study of dust event sources from the Gobi and Taklamakan deserts: An investigation of the horizontal evolution and topographical effect using numerical modeling and remote sensing.

    Science.gov (United States)

    Fan, Jin; Yue, Xiaoying; Sun, Qinghua; Wang, Shigong

    2017-06-01

    A severe dust event occurred from April 23 to April 27, 2014, in East Asia. A state-of-the-art online atmospheric chemistry model, WRF/Chem, was combined with a dust model, GOCART, to better understand the entire process of this event. The natural color images and aerosol optical depth (AOD) over the dust source region are derived from datasets of moderate resolution imaging spectroradiometer (MODIS) loaded on a NASA Aqua satellite to trace the dust variation and to verify the model results. Several meteorological conditions, such as pressure, temperature, wind vectors and relative humidity, are used to analyze meteorological dynamic. The results suggest that the dust emission occurred only on April 23 and 24, although this event lasted for 5days. The Gobi Desert was the main source for this event, and the Taklamakan Desert played no important role. This study also suggested that the landform of the source region could remarkably interfere with a dust event. The Tarim Basin has a topographical effect as a "dust reservoir" and can store unsettled dust, which can be released again as a second source, making a dust event longer and heavier. Copyright © 2016. Published by Elsevier B.V.

  3. Fuel Cells

    DEFF Research Database (Denmark)

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Fuel cells have been the subject of intense research and development efforts for the past decades. Even so, the technology has not had its commercial breakthrough yet. This entry gives an overview of the technological challenges and status of fuel cells and discusses the most promising applications...... of the different types of fuel cells. Finally, their role in a future energy supply with a large share of fluctuating sustainable power sources, e.g., solar or wind, is surveyed....

  4. Investigation of the Performance of D2O-Cooled High-Conversion Reactors for Fuel Cycle Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Hiruta, Hikaru [Idaho National Lab. (INL), Idaho Falls, ID (United States); Youinou, Gilles [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2013-09-01

    This report presents FY13 activities for the analysis of D2O cooled tight-pitch High-Conversion PWRs (HCPWRs) with U-Pu and Th-U fueled cores aiming at break-even or near breeder conditions while retaining the negative void reactivity. The analyses are carried out from several aspects which could not be covered in FY12 activities. SCALE 6.1 code system is utilized, and a series of simple 3D fuel pin-cell models are developed in order to perform Monte Carlo based criticality and burnup calculations. The performance of U-Pu fueled cores with axial and internal blankets is analyzed in terms of their impact on the relative fissile Pu mass balance, initial Pu enrichment, and void coefficient. In FY12, Pu conversion performances of D2O-cooled HCPWRs fueled with MOX were evaluated with small sized axial/internal DU blankets (approximately 4cm of axial length) in order to ensure the negative void reactivity, which evidently limits the conversion performance of HCPWRs. In this fiscal year report, the axial sizes of DU blankets are extended up to 30 cm in order to evaluate the amount of DU necessary to reach break-even and/or breeding conditions. Several attempts are made in order to attain the milestone of the HCPWR designs (i.e., break-even condition and negative void reactivity) by modeling of HCPWRs under different conditions such as boiling of D2O coolant, MOX with different 235U enrichment, and different target burnups. A similar set of analyses are performed for Th-U fueled cores. Several promising characteristics of 233U over other fissile like 239Pu and 235U, most notably its higher fission neutrons per absorption in thermal and epithermal ranges combined with lower ___ in the fast range than 239Pu allows Th-U cores to be taller than MOX ones. Such an advantage results in 4% higher relative fissile mass balance than that of U-Pu fueled cores while retaining the negative void

  5. Event Modeling

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2001-01-01

    are dynamic and we present a modeling approach that can be used to model such dynamics. We characterize events as both information objects and change agents (Bækgaard 1997). When viewed as information objects events are phenomena that can be observed and described. For example, borrow events in a library can......The purpose of this chapter is to discuss conceptual event modeling within a context of information modeling. Traditionally, information modeling has been concerned with the modeling of a universe of discourse in terms of information structures. However, most interesting universes of discourse...... be characterized by their occurrence times and the participating books and borrowers. When we characterize events as information objects we focus on concepts like information structures. When viewed as change agents events are phenomena that trigger change. For example, when borrow event occurs books are moved...

  6. Fuel cells:

    DEFF Research Database (Denmark)

    Sørensen, Bent

    2013-01-01

    A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil...... and nuclear fuel-based energy technologies....

  7. Investigations of Multiple Swirl-Venturi Fuel Injector Concepts: Recent Experimental Optical Measurement Results for 1-Point, 7-Point, and 9-Point Configurations

    Science.gov (United States)

    Hicks, Yolanda R.; Anderson, Robert C.; Tedder, Sarah A.; Tacina, Kathleen M.

    2015-01-01

    This paper presents results obtained during testing in optically-accessible, JP8-fueled, flame tube combustors using swirl-venturi lean direct injection (LDI) research hardware. The baseline LDI geometry has 9 fuel/air mixers arranged in a 3 x 3 array within a square chamber. 2-D results from this 9-element array are compared to results obtained in a cylindrical combustor using a 7-element array and a single element. In each case, the baseline element size remains the same. The effect of air swirler angle, and element arrangement on the presence of a central recirculation zone are presented. Only the highest swirl number air swirler produced a central recirculation zone for the single element swirl-venturi LDI and the 9-element LDI, but that same swirler did not produce a central recirculation zone for the 7-element LDI, possibly because of strong interactions due to element spacing within the array.

  8. Investigation of novel solid oxide fuel cell cathodes based on impregnation of SrTixFe1-xO3-δ into ceria-based backbones

    DEFF Research Database (Denmark)

    Brinch-Larsen, Mathias; Søgaard, Martin; Hjelm, Johan

    2013-01-01

    Solid oxide fuel cell (SOFC) cathodes were prepared by impregnating the nitrates corresponding to SrTixFe1-xO3-δ (STF), x= 0; 0.1; 0.2; 0.3; 0.4 and 0.5, into a porous backbone of Ce 0.9Gd0.1O2-δ (CGO). STF was chosen as very high oxygen surface exchange rate, high ionic conductivity and electroc...

  9. Sulfate Formation Enhanced by a Cocktail of High NOx, SO2, Particulate Matter, and Droplet pH during Haze-Fog Events in Megacities in China: An Observation-Based Modeling Investigation.

    Science.gov (United States)

    Xue, Jian; Yuan, Zibing; Griffith, Stephen M; Yu, Xin; Lau, Alexis K H; Yu, Jian Zhen

    2016-07-19

    In recent years in a few Chinese megacities, fog events lasting one to a few days have been frequently associated with high levels of aerosol loading characterized by high sulfate (as high as 30 μg m(-3)), therefore termed as haze-fog events. The concomitant pollution characteristics include high gas-phase mixing ratios of SO2 (up to 71 ppbv) and NO2 (up to 69 ppbv), high aqueous phase pH (5-6), and smaller fog droplets (as low as 2 μm), resulting from intense emissions from fossil fuel combustion and construction activities supplying abundant Ca(2+). In this work, we use an observation-based model for secondary inorganic aerosols (OBM-SIA) to simulate sulfate formation pathways under conditions of haze-fog events encountered in Chinese megacities. The OBM analysis has identified, at a typical haze-fogwater pH of 5.6, the most important pathway to be oxidation of S(IV) by dissolved NO2, followed by the heterogeneous reaction of SO2 on the aerosol surface. The aqueous phase oxidation of S(IV) by H2O2 is a very minor formation pathway as a result of the high NOx conditions suppressing H2O2 formation. The model results indicate that the unique cocktail of high fogwater pH, high concentrations of NO2, SO2, and PM, and small fog droplets are capable of greatly enhancing sulfate formation. Such haze-fog conditions could lead to rapid sulfate production at night and subsequently high PM2.5 in the morning when the fog evaporates. Sulfate formation is simulated to be highly sensitive to fogwater pH, PM, and precursor gases NO2 and SO2. Such insights on major contributing factors imply that reduction of road dust and NOx emissions could lessen PM2.5 loadings in Chinese megacities during fog events.

  10. Investigation of the Chiral Magnetic Effect using Event Shape Engineering in Pb–Pb collisions at √sNN = 5.02 TeV

    CERN Document Server

    Huang, Yiwen

    2018-01-01

    The fluctuations in the initial energy density of heavy-ion collisions, reflected in the event-by-event variation of elliptic flow v2, allow an efficient selection of events corresponding to specific initial geometries. This technique, Event Shape Engineering, has been used to search for the Chiral Magnetic Effect (CME), a parity violating effect of the strong interaction. The three-particle correlator γαβ = hcos(ϕα + ϕβ − 2Ψ2)i, calculated for different combinations of charges α and β, has been employed to disentangle the CME signal from background effects in Pb–Pb collisions at √sNN = 5.02 TeV recorded by the ALICE detector. In order to constrain the CME contribution to the measured correlations, the charge-dependence of γαβ is compared with the expectations for the CME signal based on Monte Carlo calculations with magnetic field of spectators.

  11. FY 2013 Summary Report: Post-Irradiation Examination of Zircaloy-4 Samples in Target Capsules and Initiation of Bending Fatigue Testing for Used Nuclear Fuel Vibration Integrity Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Howard, Richard H [ORNL; Yan, Yong [ORNL; Wang, Jy-An John [ORNL; Ott, Larry J [ORNL; Howard, Rob L [ORNL

    2013-10-01

    This report documents ongoing work performed at Oak Ridge National Laboratory (ORNL) for the Department of Energy, Office of Fuel Cycle Technology Used Fuel Disposition Campaign (UFDC), and satisfies the deliverable for milestone M2FT-13OR0805041, “Data Report on Hydrogen Doping and Irradiation in HFIR.” This work is conducted under WBS 1.02.08.05, Work Package FT-13OR080504 ST “Storage and Transportation-Experiments – ORNL.” The objectives of work packages that make up the S&T Experiments Control Account are to conduct the separate effects tests (SET) and small-scale tests that have been identified in the Used Nuclear Fuel Storage and Transportation Data Gap Prioritization (FCRD-USED-2012-000109). In FY 2013, the R&D focused on cladding and container issues and small-scale tests as identified in Sections A-2.9 and A-2.12 of the prioritization report.

  12. Reports of Perceived Adverse Events of Stimulant Medication on Cognition, Motivation, and Mood: Qualitative Investigation and the Generation of Items for the Medication and Cognition Rating Scale.

    Science.gov (United States)

    Kovshoff, Hanna; Banaschewski, Tobias; Buitelaar, Jan K; Carucci, Sara; Coghill, David; Danckaerts, Marina; Dittmann, Ralf W; Falissard, Bruno; Grimshaw, Dina Gojkovic; Hollis, Chris; Inglis, Sarah; Konrad, Kerstin; Liddle, Elizabeth; McCarthy, Suzanne; Nagy, Peter; Thompson, Margaret; Wong, Ian C K; Zuddas, Alessandro; Sonuga-Barke, Edmund J S

    2016-08-01

    There is no questionnaire to specifically monitor perceived adverse events of methylphenidate (MPH) on cognition, motivation, and mood. The current study therefore had two goals. First, to harvest accounts of such putative events from transcripts of interviews in samples enriched for such potential experiences. Second, to use the derived data to generate items for a new questionnaire that can be used for monitoring such events in medication trials or routine clinical care. Following a literature search aimed at identifying associations between MPH and cognition and/or motivation, a qualitative semistructured interview was designed to focus specifically on the domains of cognition (i.e., reasoning, depth/breadth of thinking, intellectual capacity, and creativity) and motivation (i.e., drive, effort, and attitudes toward rewards/incentives). Interviews were conducted with 45 participants drawn from the following four groups: (a) clinicians, child and adolescent psychiatrists, and pediatricians specializing in attention-deficit/hyperactivity disorder (ADHD) (n = 15); (2) teachers, with experience of teaching at least 10 medicated children with ADHD (n = 10); (3) parents of children with ADHD (n = 8) treated with MPH; and (4) adolescents/adults with ADHD (n = 12). Purposeful sampling was used to selectively recruit ADHD participants whose histories suggested a degree of vulnerability to MPH adverse events. Data were analyzed using a deductive approach to content analysis. While we probed purposefully for cognitive and motivational adverse events, a third domain, related to mood, emerged from the reports. Therefore, three domains, each with a number of subdomains, were identified from the interview accounts: (i) Cognition (six subdomains; attention/concentration, changes in thinking, reduced creativity, sensory overload, memory, slower processing speed); (ii) motivation (four subdomains; loss of intrinsic motivation for goal-directed activities, external

  13. Gas-Cooled Reactor Programs annual progress report for period ending December 31, 1973. [HTGR fuel reprocessing, fuel fabrication, fuel irradiation, core materials, and fission product distribution; GCFR fuel irradiation and steam generator modeling

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.; Coobs, J.H.; Lotts, A.L.

    1976-04-01

    Progress is summarized in studies relating to HTGR fuel reprocessing, refabrication, and recycle; HTGR fuel materials development and performance testing; HTGR PCRV development; HTGR materials investigations; HTGR fuel chemistry; HTGR safety studies; and GCFR irradiation experiments and steam generator modeling.

  14. SENTINEL EVENTS

    Directory of Open Access Journals (Sweden)

    Andrej Robida

    2004-09-01

    Full Text Available Background. The Objective of the article is a two year statistics on sentinel events in hospitals. Results of a survey on sentinel events and the attitude of hospital leaders and staff are also included. Some recommendations regarding patient safety and the handling of sentinel events are given.Methods. In March 2002 the Ministry of Health introduce a voluntary reporting system on sentinel events in Slovenian hospitals. Sentinel events were analyzed according to the place the event, its content, and root causes. To show results of the first year, a conference for hospital directors and medical directors was organized. A survey was conducted among the participants with the purpose of gathering information about their view on sentinel events. One hundred questionnaires were distributed.Results. Sentinel events. There were 14 reports of sentinel events in the first year and 7 in the second. In 4 cases reports were received only after written reminders were sent to the responsible persons, in one case no reports were obtained. There were 14 deaths, 5 of these were in-hospital suicides, 6 were due to an adverse event, 3 were unexplained. Events not leading to death were a suicide attempt, a wrong side surgery, a paraplegia after spinal anaesthesia, a fall with a femoral neck fracture, a damage of the spleen in the event of pleural space drainage, inadvertent embolization with absolute alcohol into a femoral artery and a physical attack on a physician by a patient. Analysis of root causes of sentinel events showed that in most cases processes were inadequate.Survey. One quarter of those surveyed did not know about the sentinel events reporting system. 16% were having actual problems when reporting events and 47% beleived that there was an attempt to blame individuals. Obstacles in reporting events openly were fear of consequences, moral shame, fear of public disclosure of names of participants in the event and exposure in mass media. The majority of

  15. Investigating the Evolution of Southern California Salt Marshes: A Facies Model to Understand the Influence of Seismic Events on Environmental Resiliency and Sustainability

    Science.gov (United States)

    Aranda, A. N.; Carlin, J. A.; Rhodes, B. P.; Kirby, M.

    2016-02-01

    Only 10-20% of the US Pacific coast is estimated to be suitable for marsh development. In southern California specifically, marshes are disappearing ecosystems due to high population and urbanization. The future environmental impacts from climate change on these ecosystems are complicated not only by anthropogenic influences, but also by seismic activity in the region. In general, marsh evolution and response to seismic activity has yet to be fully explored in southern California. This study aims to develop a sediment facies model for salt marsh evolution in southern California by utilizing the salt marshes of the Seal Beach Wetlands (SBW). The SBW is an ideal location to develop the facies model because it straddles the active Newport-Inglewood Fault Zone. We collected sediment cores from the SBW that underwent a variety of sedimentological and geochemical analyses including grain size, X-Ray Fluorescence core scanning, magnetic susceptibility, and loss-on-ignition.. The results show a facies model consisting of sequences of marsh accretion punctuated by seismic events. These seismic events caused the marsh to subside, effectively re-setting marsh development from peat generation at a vegetated marsh state, to subtidal to intertidal mud deposition. The model also allowed us to qualify and quantify marsh recovery as inferred from event intensity, where what we perceived as more intense events resulted in more significant ecosystem disturbances and longer recovery times. Understanding this interplay between seismic activity and marsh development highlights the fragile nature of these ecosystems to climate change and sea level rise, as these stresses will only become amplified by seismic events.

  16. Fuel failures in the Connecticut Yankee reactor (Haddam Neck). Addendum to NP-2119

    Energy Technology Data Exchange (ETDEWEB)

    Raven, L.F.A.; Howl, D.; Naylor, J.; Pitek, M.T.; Clink, L.J.

    1984-05-01

    Significant levels of fuel rod failures were observed in the batch 8 fuel assemblies of the Connecticut Yankee reactor. Results of detailed poolside and hot cell examinations, reported earlier in NP-2119, indicated the failure mechanism was stress corrosion cracking initiating on the clad outer surface. The sources of cladding stresses were believed to be (a) fuel pellet chips wedged in the cladding gap, (b) swelling of highly nondensifying batch 8 fuel, and (c) potentially harmful effects of a power change event that occurred near the end of the second cycle of irradiation for batch 8. This report reviews the 1977-78 experience and conclusions of the earlier investigations against the background of the total operational experience of the reactor from initial startup to the present time. It provides more details on operating conditions and uses the results of SLEUTH-SEER analyses to interpret the effects of operational maneuvers. The investigation adds more evidence for the importance of the ramp effects.

  17. Fuel cell-fuel cell hybrid system

    Science.gov (United States)

    Geisbrecht, Rodney A.; Williams, Mark C.

    2003-09-23

    A device for converting chemical energy to electricity is provided, the device comprising a high temperature fuel cell with the ability for partially oxidizing and completely reforming fuel, and a low temperature fuel cell juxtaposed to said high temperature fuel cell so as to utilize remaining reformed fuel from the high temperature fuel cell. Also provided is a method for producing electricity comprising directing fuel to a first fuel cell, completely oxidizing a first portion of the fuel and partially oxidizing a second portion of the fuel, directing the second fuel portion to a second fuel cell, allowing the first fuel cell to utilize the first portion of the fuel to produce electricity; and allowing the second fuel cell to utilize the second portion of the fuel to produce electricity.

  18. Event Modeling

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2001-01-01

    The purpose of this chapter is to discuss conceptual event modeling within a context of information modeling. Traditionally, information modeling has been concerned with the modeling of a universe of discourse in terms of information structures. However, most interesting universes of discourse...... are dynamic and we present a modeling approach that can be used to model such dynamics.We characterize events as both information objects and change agents (Bækgaard 1997). When viewed as information objects events are phenomena that can be observed and described. For example, borrow events in a library can...

  19. Proceedings of the Water Reactor Fuel Performance Meeting - WRFPM / Top Fuel 2009

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-06-15

    SFEN, ENS, SNR, ANS, AESJ, CNS KNS, IAEA and NEA are jointly organizing the 2009 International Water Reactor Fuel Performance / TopFuel 2009 Meeting following the 2008 KNS Water Reactor Performance Meeting held during October 19-23, 2008 in Seoul, Korea. This meeting is held annually on a tri-annual rotational basis in Europe, USA and Asia. In 2009, this meeting will be held in Paris, September 6-10, 2009 in coordination with the Global 2009 Conference at the same date and place. That would lead to a common opening session, some common technical presentations, a common exhibition and common social events. The technical scope of the meeting includes all aspects of nuclear fuel from fuel rod to core design as well as manufacturing, performance in commercial and test reactors or on-going and future developments and trends. Emphasis will be placed on fuel reliability in the general context of nuclear 'Renaissance' and recycling perspective. The meeting includes selectively front and/or back end issues that impact fuel designs and performance. In this frame, the conference track devoted to 'Concepts for transportation and interim storage of spent fuels and conditioned waste' will be shared with 'GLOBAL' conference. Technical Tracks: - 1. Fuel Performance, Reliability and Operational Experience: Fuel operating experience and performance; experience with high burn-up fuels; water side corrosion; stress corrosion cracking; MOX fuel performance; post irradiation data on lead fuel assemblies; radiation effects; water chemistry and corrosion counter-measures. - 2. Transient Fuel Behaviour and Safety Related Issues: Transient fuel behavior and criteria (RIA, LOCA, ATWS, Ramp tests..). Fuel safety-related issues such as PCI (pellet cladding interaction), transient fission gas releases and cladding bursting/ballooning during transient events - Advances in fuel performance modeling and core reload methodology, small and large-scale fuel testing

  20. Committed Sport Event Volunteers

    Science.gov (United States)

    Han, Keunsu; Quarterman, Jerome; Strigas, Ethan; Ha, Jaehyun; Lee, Seungbum

    2013-01-01

    The purpose of this study was to investigate the relationships among selected demographic characteristics (income, education and age), motivation and commitment of volunteers at a sporting event. Three-hundred and five questionnaires were collected from volunteers in a marathon event and analyzed using structural equation modeling (SEM). Based on…

  1. Sphygmomanometrically determined pulse pressure is a powerful independent predictor of recurrent events after myocardial infarction in patients with impaired left ventricular function. SAVE investigators. Survival and Ventricular Enlargement.

    Science.gov (United States)

    Mitchell, G F; Moyé, L A; Braunwald, E; Rouleau, J L; Bernstein, V; Geltman, E M; Flaker, G C; Pfeffer, M A

    1997-12-16

    There is increasing evidence of a link between conduit vessel stiffness and cardiovascular events, although the association has never been tested in a large post-myocardial infarction patient population. We evaluated the relationship between baseline pulse pressure, measured by sphygmomanometry 3 to 16 days after myocardial infarction, and subsequent adverse clinical events in the 2231 patients enrolled in the SAVE Trial. Increased pulse pressure was associated with increased age, left ventricular ejection fraction, female sex, history of prior infarction, diabetes, and hypertension and use of digoxin and calcium channel blockers. Over a 42-month period, there were 503 deaths, 422 cardiovascular deaths, and 303 myocardial infarctions. Pulse pressure was significantly related to each of these end points as a univariate predictor. In a multivariate analysis, pulse pressure remained a significant predictor of total mortality (relative risk, 1.08 per 10 mm Hg increment in pulse pressure; 95% CI, 1.00 to 1.17; Pmyocardial infarction (relative risk, 1.12; 95% CI, 1.01 to 1.23; Pmyocardial infarction, diabetes, or hypertension; and treatment with beta-blockers, calcium channel blockers, digoxin, aspirin, or thrombolytic therapy. These data provide strong evidence for a link between pulse pressure, which is related to conduit vessel stiffness, and subsequent cardiovascular events after myocardial infarction in patients with left ventricular dysfunction.

  2. Fuel Flexible, Low Emission Catalytic Combustor for Opportunity Fuel Applications

    Energy Technology Data Exchange (ETDEWEB)

    Eteman, Shahrokh

    2013-06-30

    Limited fuel resources, increasing energy demand and stringent emission regulations are drivers to evaluate process off-gases or process waste streams as fuels for power generation. Often these process waste streams have low energy content and/or highly reactive components. Operability of low energy content fuels in gas turbines leads to issues such as unstable and incomplete combustion. On the other hand, fuels containing higher-order hydrocarbons lead to flashback and auto-ignition issues. Due to above reasons, these fuels cannot be used directly without modifications or efficiency penalties in gas turbine engines. To enable the use of these wide variety of fuels in gas turbine engines a rich catalytic lean burn (RCL®) combustion system was developed and tested in a subscale high pressure (10 atm.) rig. The RCL® injector provided stability and extended turndown to low Btu fuels due to catalytic pre-reaction. Previous work has shown promise with fuels such as blast furnace gas (BFG) with LHV of 85 Btu/ft3 successfully combusted. This program extends on this work by further modifying the combustor to achieve greater catalytic stability enhancement. Fuels containing low energy content such as weak natural gas with a Lower Heating Value (LHV) of 6.5 MJ/m3 (180 Btu/ft3 to natural gas fuels containing higher hydrocarbon (e.g ethane) with LHV of 37.6 MJ/m3 (1010 Btu/ft3) were demonstrated with improved combustion stability; an extended turndown (defined as the difference between catalytic and non-catalytic lean blow out) of greater than 250oF was achieved with CO and NOx emissions lower than 5 ppm corrected to 15% O2. In addition, for highly reactive fuels the catalytic region preferentially pre-reacted the higher order hydrocarbons with no events of flashback or auto-ignition allowing a stable and safe operation with low NOx and CO emissions.

  3. Nalco Fuel Tech

    Energy Technology Data Exchange (ETDEWEB)

    Michalak, S.

    1995-12-31

    The Nalco Fuel Tech with its seat at Naperville (near Chicago), Illinois, is an engineering company working in the field of technology and equipment for environmental protection. A major portion of NALCO products constitute chemical materials and additives used in environmental protection technologies (waste-water treatment plants, water treatment, fuel modifiers, etc.). Basing in part on the experience, laboratories and RD potential of the mother company, the Nalco Fuel Tech Company developed and implemented in the power industry a series of technologies aimed at the reduction of environment-polluting products of fuel combustion. The engineering solution of Nalco Fuel Tech belong to a new generation of environmental protection techniques developed in the USA. They consist in actions focused on the sources of pollutants, i.e., in upgrading the combustion chambers of power engineering plants, e.g., boilers or communal and/or industrial waste combustion units. The Nalco Fuel Tech development and research group cooperates with leading US investigation and research institutes.

  4. Thermal behavior analysis of PWR fuel during RIA at various fuel burnups using modified theatre code

    Directory of Open Access Journals (Sweden)

    Nawaz Amjad

    2016-01-01

    Full Text Available The fuel irradiation and burnup causes geometrical and dimensional changes in the fuel rod which affects its thermal resistance and ultimately affects the fuel rod behavior during steady-state and transient conditions. The consistent analysis of fuel rod thermal performance is essential for precise evaluation of reactor safety in operational transients and accidents. In this work, analysis of PWR fuel rod thermal performance is carried out under steady-state and transient conditions at different fuel burnups. The analysis is performed by using thermal hydraulic code, THEATRe. The code is modified by adding burnup dependent fuel rod behavior models. The original code uses as-fabricated fuel rod dimensions during steady-state and transient conditions which can be modified to perform more consistent reactor safety analysis. AP1000 reactor is considered as a reference reactor for this analysis. The effect of burnup on steady-state fuel rod parameters has been investigated. For transient analysis, hypothetical reactivity initiated accident was simulated by considering a triangular power pulse of variable pulse height (relative to the full power reactor operating conditions and pulse width at different fuel burnups which corresponds to fresh fuel, low and medium burnup fuels. The effect of power pulse height, pulse width and fuel burnup on fuel rod temperatures has been investigated. The results of reactivity initiated accident analysis show that the fuel failure mechanisms are different for fresh fuel and fuel at different burnup levels. The fuel failure in fresh fuel is expected due to fuel melting as fuel temperature increases with increase in pulse energy (pulse height. However, at relatively higher burnups, the fuel failure is expected due to cladding failure caused by strong pellet clad mechanical interaction, where, the contact pressure increases beyond the cladding yield strength.

  5. Seismic behaviour of fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    Song, Heuy Gap; Jhung, Myung Jo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1993-11-01

    A general approach for the dynamic time-history analysis of the reactor core is presented in this paper as a part of the fuel assembly qualification program. Several detailed core models are set up to reflect the placement of the fuel assemblies within the core shroud. Peak horizontal responses are obtained for each model for the motions induced from earthquake. The dynamic responses such as fuel assembly shear force, bending moment and displacement, and spacer grid impact loads are carefully investigated. Also, the sensitivity responses are obtained for the earthquake motions and the fuel assembly non-linear response characteristics are discussed. (Author) 9 refs., 24 figs., 1 tab.

  6. Investigation of carbon supported PtW catalysts as CO tolerant anodes at high temperature in proton exchange membrane fuel cell

    Science.gov (United States)

    Hassan, Ayaz; Paganin, Valdecir A.; Ticianelli, Edson A.

    2016-09-01

    The CO tolerance mechanism and the stability of carbon supported PtW electrocatalysts are evaluated in the anode of a proton exchange membrane fuel cell (PEMFC) at two different temperatures. The electrocatalysts are characterized by energy dispersive spectroscopy, X-ray diffraction, and transmission electron spectroscopy. Employed electrochemical techniques include cyclic voltammetry, CO stripping, fuel cell polarization, and online mass spectrometry. At a cell temperature of 85 °C, the PtW/C catalyst shows higher CO tolerance compared to Pt/C due an electronic effect of WOx in the Pt 5d band, which reduces the CO adsorption. An increase in hydrogen oxidation activity in the presence of CO is observed for both the catalysts at a higher temperature, due to the decrease of the Pt-CO coverage. A reduction in the current densities occurs for the PtW/C catalyst in both polarization curves and cyclic voltammograms after 5000 cycles of the anode in the range of 0.1-0.7 V vs. RHE at 50 mVs-1. This decrease in performance is assigned to the dissolution of W, with a consequent increase in the membrane resistivity. However, the observed decline of performance is small either in the presence of pure H2 or in the presence of H2/CO.

  7. Ignition of alkane-rich FACE gasoline fuels and their surrogate mixtures

    KAUST Repository

    Sarathy, Mani

    2015-01-01

    Petroleum derived gasoline is the most used transportation fuel for light-duty vehicles. In order to better understand gasoline combustion, this study investigated the ignition propensity of two alkane-rich FACE (Fuels for Advanced Combustion Engines) gasoline test fuels and their corresponding PRF (primary reference fuel) blend in fundamental combustion experiments. Shock tube ignition delay times were measured in two separate facilities at pressures of 10, 20, and 40 bar, temperatures from 715 to 1500 K, and two equivalence ratios. Rapid compression machine ignition delay times were measured for fuel/air mixtures at pressures of 20 and 40 bar, temperatures from 632 to 745 K, and two equivalence ratios. Detailed hydrocarbon analysis was also performed on the FACE gasoline fuels, and the results were used to formulate multi-component gasoline surrogate mixtures. Detailed chemical kinetic modeling results are presented herein to provide insights into the relevance of utilizing PRF and multi-component surrogate mixtures to reproduce the ignition behavior of the alkane-rich FACE gasoline fuels. The two FACE gasoline fuels and their corresponding PRF mixture displayed similar ignition behavior at intermediate and high temperatures, but differences were observed at low temperatures. These trends were mimicked by corresponding surrogate mixture models, except for the amount of heat release in the first stage of a two-stage ignition events, when observed. © 2014 The Combustion Institute.

  8. Experimental Study of Turbine Fuel Thermal Stability in an Aircraft Fuel System Simulator

    Science.gov (United States)

    Vranos, A.; Marteney, P. J.

    1980-01-01

    The thermal stability of aircraft gas turbines fuels was investigated. The objectives were: (1) to design and build an aircraft fuel system simulator; (2) to establish criteria for quantitative assessment of fuel thermal degradation; and (3) to measure the thermal degradation of Jet A and an alternative fuel. Accordingly, an aircraft fuel system simulator was built and the coking tendencies of Jet A and a model alternative fuel (No. 2 heating oil) were measured over a range of temperatures, pressures, flows, and fuel inlet conditions.

  9. RF Coupling into the Fuel Tank of a Large Transport Aircraft from Intentionally Transmitting Peds in the Passenger Cabin

    Science.gov (United States)

    Nguyen, Truong X.; Dudley, Kenneth L.; Scearce, Stephen A.; Ely, Jay J.; Richardson, Robert E.; Hatfield, Michael O.

    2000-01-01

    An investigation was performed to study the potential for radio frequency (RF) power radiated from Portable Electronic Devices (PEDs) to create an arcing/sparking event within the fuel tank of a large transport aircraft. This paper describes the experimental methods used for measuring RF coupling to the fuel tank and Fuel Quantity Indication System (FQIS) wiring from PED sources located in the passenger cabin. To allow comparison of voltage/current data obtained in a laboratory chamber FQIS installation to an actual aircraft FQIS installation, aircraft fuel tank RF reverberation characteristics were also measured. Results from the measurements, along with a survey of threats from typical intentional transmitting PEDs are presented. The resulting worst-case power coupled onto fuel tank FQIS wiring is derived. The same approach can be applied to measure RF coupling into various other aircraft systems.

  10. Studies of DNA repair in saccharomyces cerevisiae. I. Characterization of a new allele of RAD6. II. Investigation of events in the first cell cycle after DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Douthwright-Fasse, Jane Ann [Univ. of Rochester, NY (United States)

    1979-01-01

    Studies in two independent, but related, areas of DNA repair have been carried out in Saccharomyces cerevisiae; characterization of a new allele in the RAD6 gene which suggests that the gene is multifunctional, and utilization of photoreactivation as a probe of events occurring during the first cell cycle after DNA damage. Strains carrying the new allele, designated rad6-4, are as sensitive to uv and ionizing radiation as those carrying rad6-1 or rad6-3 but, unlike them, are capable of induced mutagenesis and sporulation. Although rad6-4 may well be a missense mutation, the evidence shows that it is unlikely that this phenotype is due to leakiness. Instead, the data suggest that the RAD6 gene is multifunctional. One function is necessary to recover from DNA damage in an error-free manner, and the other is concerned with mutagenic processes and sporulation. Rad6-1 and rad6-3 strains are deficient in both of these functions, while rad6-4 strains are deficient only in the error-free function. The loss of photoreversibility (LOP) of ultraviolet induced mutations to arginine independence in an excision defective strain carrying arg4-17 examines the events occurring in the first cell cycle after DNA damage. LOP is dependent upon de novo protein synthesis. LOP begins immediately after UV irradiation, before semiconservative DNA synthesis takes place, and is complete after four hours in growth medium.There is no evidence indicating whether the normal function of the protein is involved in excision repair, or in one of the two repair processes believed to be inducible; induced mutagenesis or recombinational repair.

  11. Using naturalistic driving study data to investigate the impact of driver distraction on driver's brake reaction time in freeway rear-end events in car-following situation.

    Science.gov (United States)

    Gao, Jingru; Davis, Gary A

    2017-12-01

    The rear-end crash is one of the most common freeway crash types, and driver distraction is often cited as a leading cause of rear-end crashes. Previous research indicates that driver distraction could have negative effects on driving performance, but the specific association between driver distraction and crash risk is still not fully revealed. This study sought to understand the mechanism by which driver distraction, defined as secondary task distraction, could influence crash risk, as indicated by a driver's reaction time, in freeway car-following situations. A statistical analysis, exploring the causal model structure regarding drivers' distraction impacts on reaction times, was conducted. Distraction duration, distraction scenario, and secondary task type were chosen as distraction-related factors. Besides, exogenous factors including weather, visual obstruction, lighting condition, traffic density, and intersection presence and endogenous factors including driver age and gender were considered. There was an association between driver distraction and reaction time in the sample freeway rear-end events from SHRP 2 NDS database. Distraction duration, the distracted status when a leader braked, and secondary task type were related to reaction time, while all other factors showed no significant effect on reaction time. The analysis showed that driver distraction duration is the primary direct cause of the increase in reaction time, with other factors having indirect effects mediated by distraction duration. Longer distraction duration, the distracted status when a leader braked, and engaging in auditory-visual-manual secondary task tended to result in longer reaction times. Given drivers will be distracted occasionally, countermeasures which shorten distraction duration or avoid distraction presence while a leader vehicle brakes are worth considering. This study helps better understand the mechanism of freeway rear-end events in car-following situations, and

  12. Fuel Cell Equivalent Electric Circuit Parameter Mapping

    DEFF Research Database (Denmark)

    Jeppesen, Christian; Zhou, Fan; Andreasen, Søren Juhl

    In this work a simple model for a fuel cell is investigated for diagnostic purpose. The fuel cell is characterized, with respect to the electrical impedance of the fuel cell at non-faulty conditions and under variations in load current. Based on this the equivalent electrical circuit parameters can...

  13. Fuel cells for electrochemical energy conversion

    Science.gov (United States)

    O'Hayre, Ryan P.

    2017-07-01

    This short article provides an overview of fuel cell science and technology. This article is intended to act as a "primer" on fuel cells that one can use to begin a deeper investigation into this fascinating and promising technology. You will learn what fuel cell are, how they work, and what significant advantages and disadvantages they present.

  14. Hydrogen-enriched fuels

    Energy Technology Data Exchange (ETDEWEB)

    Roser, R. [NRG Technologies, Inc., Reno, NV (United States)

    1998-08-01

    NRG Technologies, Inc. is attempting to develop hardware and infrastructure that will allow mixtures of hydrogen and conventional fuels to become viable alternatives to conventional fuels alone. This commercialization can be successful if the authors are able to achieve exhaust emission levels of less than 0.03 g/kw-hr NOx and CO; and 0.15 g/kw-hr NMHC at full engine power without the use of exhaust catalysts. The major barriers to achieving these goals are that the lean burn regimes required to meet exhaust emissions goals reduce engine output substantially and tend to exhibit higher-than-normal total hydrocarbon emissions. Also, hydrogen addition to conventional fuels increases fuel cost, and reduces both vehicle range and engine output power. Maintaining low emissions during transient driving cycles has not been demonstrated. A three year test plan has been developed to perform the investigations into the issues described above. During this initial year of funding research has progressed in the following areas: (a) a cost effective single-cylinder research platform was constructed; (b) exhaust gas speciation was performed to characterize the nature of hydrocarbon emissions from hydrogen-enriched natural gas fuels; (c) three H{sub 2}/CH{sub 4} fuel compositions were analyzed using spark timing and equivalence ratio sweeping procedures and finally; (d) a full size pick-up truck platform was converted to run on HCNG fuels. The testing performed in year one of the three year plan represents a baseline from which to assess options for overcoming the stated barriers to success.

  15. Reforming of fuel inside fuel cell generator

    Science.gov (United States)

    Grimble, Ralph E.

    1988-01-01

    Disclosed is an improved method of reforming a gaseous reformable fuel within a solid oxide fuel cell generator, wherein the solid oxide fuel cell generator has a plurality of individual fuel cells in a refractory container, the fuel cells generating a partially spent fuel stream and a partially spent oxidant stream. The partially spent fuel stream is divided into two streams, spent fuel stream I and spent fuel stream II. Spent fuel stream I is burned with the partially spent oxidant stream inside the refractory container to produce an exhaust stream. The exhaust stream is divided into two streams, exhaust stream I and exhaust stream II, and exhaust stream I is vented. Exhaust stream II is mixed with spent fuel stream II to form a recycle stream. The recycle stream is mixed with the gaseous reformable fuel within the refractory container to form a fuel stream which is supplied to the fuel cells. Also disclosed is an improved apparatus which permits the reforming of a reformable gaseous fuel within such a solid oxide fuel cell generator. The apparatus comprises a mixing chamber within the refractory container, means for diverting a portion of the partially spent fuel stream to the mixing chamber, means for diverting a portion of exhaust gas to the mixing chamber where it is mixed with the portion of the partially spent fuel stream to form a recycle stream, means for injecting the reformable gaseous fuel into the recycle stream, and means for circulating the recycle stream back to the fuel cells.

  16. Coking of JP-4 fuels in electrically heated metal tubes

    Science.gov (United States)

    Smith, Arthur L; Cook, William P; Hlavin, Vincent F

    1956-01-01

    A limited exploratory investigation of the rate of coking of four JP-4 fuels in electrically heated metal tubes was conducted in order to provide design information for fuel prevaporizers for turbojet-engine combustors. The fuels tested included two production and two minimum-quality JP-4 type fuels. The heating tube was operated at fuel pressures of approximately 500, 400, and 50 pounds per square inch. The operating fuel temperature was varied between approximately 600 degrees and 1200 degrees F.

  17. Experimental analysis of injection characteristics using biodiesel fuel

    OpenAIRE

    Kegl, Breda; Hribernik, Aleš

    2012-01-01

    This paper deals with injection characteristics using different fuels at different fuel temperatures. The fuels under consideration are neat biodiesel from rapeseed oil and some blends with diesel as well as neat mineral diesel D2. The fuel and fuel temperature influences are investigated experimentally in the mechanically controlled diesel fuel injection M system. At first, attention is focused on the injection characteristics, especially on fuelling, mean injection rate, mean injection pres...

  18. Material-dependent and material-independent selection processes in the frontal and parietal lobes: an event-related fMRI investigation of response competition

    Science.gov (United States)

    Hazeltine, Eliot; Bunge, Silvia A.; Scanlon, Michael D.; Gabrieli, John D E.

    2003-01-01

    The present study used the flanker task [Percept. Psychophys. 16 (1974) 143] to identify neural structures that support response selection processes, and to determine which of these structures respond differently depending on the type of stimulus material associated with the response. Participants performed two versions of the flanker task while undergoing event-related functional magnetic resonance imaging (fMRI). Both versions of the task required participants to respond to a central stimulus regardless of the responses associated with simultaneously presented flanking stimuli, but one used colored circle stimuli and the other used letter stimuli. Competition-related activation was identified by comparing Incongruent trials, in which the flanker stimuli indicated a different response than the central stimulus, to Neutral stimuli, in which the flanker stimuli indicated no response. A region within the right inferior frontal gyrus exhibited significantly more competition-related activation for the color stimuli, whereas regions within the middle frontal gyri of both hemispheres exhibited more competition-related activation for the letter stimuli. The border of the right middle frontal and inferior frontal gyri and the anterior cingulate cortex (ACC) were significantly activated by competition for both types of stimulus materials. Posterior foci demonstrated a similar pattern: left inferior parietal cortex showed greater competition-related activation for the letters, whereas right parietal cortex was significantly activated by competition for both materials. These findings indicate that the resolution of response competition invokes both material-dependent and material-independent processes.

  19. Is 4/20 an Event-Specific Marijuana Holiday? A Daily Diary Investigation of Marijuana Use and Consequences Among College Students.

    Science.gov (United States)

    Bravo, Adrian J; Pearson, Matthew R; Conner, Bradley T; Parnes, Jamie E

    2017-01-01

    Given the popular association between April 20 ("4/20") and marijuana, the present study examined marijuana use and consequences on 4/20 compared with other days in order to test whether 4/20 is a high-risk, event-specific marijuana use holiday among college student marijuana users. Fifty-nine college student marijuana users from three different, large U.S. universities located in Virginia, New Mexico, and Colorado completed daily brief surveys (marijuana use (i.e., percentage of users who consumed marijuana, number of unique marijuana use sessions, subjective high/intoxication while under the influence of marijuana, and number of grams of marijuana consumed) and marijuana-related consequences. Using oneway repeated-measures analyses of variance, we found that (a) 50% of students reported using marijuana on 4/20, which was significantly more than weekdays (28%) and weekend days (37%); (b) students reported a significantly higher number of unique marijuana use sessions on 4/20 (M = 1.47) compared with weekdays (M = 0.91); and (c) students reported a significantly higher number of grams consumed on 4/20 (M = 0.79) compared with weekdays (M = 0.35) and weekend days (M = 0.47). Our study provides preliminary support that 4/20 is a day associated with increased marijuana use but provides little evidence for an association with more problematic use.

  20. An Investigation of the Critical Events and Influential Factors to the Evolution of the U.S. Man and the Biosphere Program.

    Science.gov (United States)

    Thomsen, Jennifer M

    2018-01-20

    The UNESCO Man and the Biosphere program has operated for 45 years as an international program that started in the 1970s to conserve biotic communities and provide areas for research, education, and training. The program later evolved in the 1990s to address social and environmental issues in a sustainable manner across a landscape. This program was one of the first efforts that recognized the importance of working beyond park and protected area boundaries and the need to sustain livelihoods as much as the resources. In the MAB program's infancy, the United States (U.S.) was a major advocate and leader with more than 45 biosphere reserves, most of them established in or around 1976. Yet, many political, economic, and other external factors influenced the U.S. MAB involvement in subsequent years. Consequently, the U.S. has remained largely inactive in the international MAB network for the past fifteen years until a recent push to revive the program under the leadership of the State Department and the National Park Service. Through in-depth research on two longterm U.S. bio