Life cycle evaluation of spaceflight qualified nickel-hydrogen batteries

Energy Technology Data Exchange (ETDEWEB)

Coates, D.K.; Brill, J.N. [Eagle-Picher Industries, Inc., Joplin, MO (United States). Advanced Systems Operation

1995-12-31

Life cycle test results are summarized from more than 300 spaceflight qualified nickel-hydrogen (NiH{sub 2}) battery cells currently on life test. Cells ranging in size from 4 ampere-hours (Ah) to 120 Ah are being tested under a variety of conditions to support current NiH{sub 2} battery applications. Results to date include 55,600 accelerated LEO cycles at 30% DOD; 102,840 accelerated LEO cycles at 15% DOD; 44,900 cycles under a real-time LEO profile; 44,100 cycles in real-time LEO; 30 accelerated GEO eclipse seasons and 7 real-time GEO eclipse seasons, both at 75% DOD maximum. Alternative separator materials have completed more than 40,000 charge/discharge cycles in accelerated LEO testing and advanced design electrocatalytic hydrogen electrodes have completed more than 16,000 cycles in real-time LEO testing. Common pressure vessel cell designs have completed 18,000 cycles in real-time LEO testing at 45% DOD.

Long-Term Cycling of the Magnesium Hydrogen System

DEFF Research Database (Denmark)

Pedersen, Allan Schrøder; Kjøller, John; Larsen, Bent

1984-01-01

Magnesium powder with a grain size of approximately 50γm was hydrogenated for 30 min and dehydrogenated the same time at 390°C, 515 times. A moderate loss in hydrogen storage capacity was observed and was ascribed to a measured decrease in reaction kinetics as the cycle number increased. The time...

Advanced Electrochemical Technologies for Hydrogen Production by Alternative Thermochemical Cycles

Energy Technology Data Exchange (ETDEWEB)

Lvov, Serguei; Chung, Mike; Fedkin, Mark; Lewis, Michele; Balashov, Victor; Chalkova, Elena; Akinfiev, Nikolay; Stork, Carol; Davis, Thomas; Gadala-Maria, Francis; Stanford, Thomas; Weidner, John; Law, Victor; Prindle, John

2011-01-06

Hydrogen fuel is a potentially major solution to the problem of climate change, as well as addressing urban air pollution issues. But a key future challenge for hydrogen as a clean energy carrier is a sustainable, low-cost method of producing it in large capacities. Most of the world's hydrogen is currently derived from fossil fuels through some type of reforming processes. Nuclear hydrogen production is an emerging and promising alternative to the reforming processes for carbon-free hydrogen production in the future. This report presents the main results of a research program carried out by a NERI Consortium, which consisted of Penn State University (PSU) (lead), University of South Carolina (USC), Tulane University (TU), and Argonne National Laboratory (ANL). Thermochemical water decomposition is an emerging technology for large-scale production of hydrogen. Typically using two or more intermediate compounds, a sequence of chemical and physical processes split water into hydrogen and oxygen, without releasing any pollutants externally to the atmosphere. These intermediate compounds are recycled internally within a closed loop. While previous studies have identified over 200 possible thermochemical cycles, only a few have progressed beyond theoretical calculations to working experimental demonstrations that establish scientific and practical feasibility of the thermochemical processes. The Cu-Cl cycle has a significant advantage over other cycles due to lower temperature requirements – around 530 °C and below. As a result, it can be eventually linked with the Generation IV thermal power stations. Advantages of the Cu-Cl cycle over others include lower operating temperatures, ability to utilize low-grade waste heat to improve energy efficiency, and potentially lower cost materials. Another significant advantage is a relatively low voltage required for the electrochemical step (thus low electricity input). Other advantages include common chemical agents and

Life cycle assessment of hydrogen energy pattern

International Nuclear Information System (INIS)

Aissani, Lynda; Bourgois, Jacques; Rousseaux, Patrick; Jabouille, Florent; Loget, Sebastien; Perier Camby, Laurent; Sessiecq, Philippe

2007-01-01

In the last decades transportation sector is a priority for environmental research. Indeed, it is the most impacting sector because it involves greenhouse emissions and fossil resources exhaustion. The Group of 'Ecole des Mines' (GEM), in France, carries out studies concerning clean and renewable energies for this sector with the 'H2-PAC' project. The GEM with four teams performs studies concerning energy systems for transportation sector and more particularly the hydrogen system. The four teams of the GEM work each one on a process of this system. More precisely, the team of Albi studies biomass gasification in order to produce synthesis gas. The team of Nantes studies purification of this gas to obtain pure hydrogen and hydrogen storage on activated carbon. The team of Paris studies fuel cell use and especially Polymer Exchange Membrane Fuel Cell. Finally, the team of St Etienne evaluates this system along its life cycle from an environmental point of view. This paper presents this environmental evaluation witch is realized according to Life Cycle Assessment (LCA) methodology. (authors)

Life cycle assessment of nuclear-based hydrogen production via thermochemical water splitting using a copper-chlorine (Cu-Cl) cycle

Science.gov (United States)

Ozbilen, Ahmet Ziyaettin

The energy carrier hydrogen is expected to solve some energy challenges. Since its oxidation does not emit greenhouse gases (GHGs), its use does not contribute to climate change, provided that it is derived from clean energy sources. Thermochemical water splitting using a Cu-Cl cycle, linked with a nuclear super-critical water cooled reactor (SCWR), which is being considered as a Generation IV nuclear reactor, is a promising option for hydrogen production. In this thesis, a comparative environmental study is reported of the three-, four- and five-step Cu-Cl thermochemical water splitting cycles with various other hydrogen production methods. The investigation uses life cycle assessment (LCA), which is an analytical tool to identify and quantify environmentally critical phases during the life cycle of a system or a product and/or to evaluate and decrease the overall environmental impact of the system or product. The LCA results for the hydrogen production processes indicate that the four-step Cu-Cl cycle has lower environmental impacts than the three- and five-step Cu-Cl cycles due to its lower thermal energy requirement. Parametric studies show that acidification potentials (APs) and global warming potentials (GWPs) for the four-step Cu-Cl cycle can be reduced from 0.0031 to 0.0028 kg SO2-eq and from 0.63 to 0.55 kg CO2-eq, respectively, if the lifetime of the system increases from 10 to 100 years. Moreover, the comparative study shows that the nuclear-based S-I and the four-step Cu-Cl cycles are the most environmentally benign hydrogen production methods in terms of AP and GWP. GWPs of the S-I and the four-step Cu-Cl cycles are 0.412 and 0.559 kg CO2-eq for reference case which has a lifetime of 60 years. Also, the corresponding APs of these cycles are 0.00241 and 0.00284 kg SO2-eq. It is also found that an increase in hydrogen plant efficiency from 0.36 to 0.65 decreases the GWP from 0.902 to 0.412 kg CO 2-eq and the AP from 0.00459 to 0.00209 kg SO2-eq for the

Thermally regenerative hydrogen/oxygen fuel cell power cycles

Science.gov (United States)

Morehouse, J. H.

1986-01-01

Two innovative thermodynamic power cycles are analytically examined for future engineering feasibility. The power cycles use a hydrogen-oxygen fuel cell for electrical energy production and use the thermal dissociation of water for regeneration of the hydrogen and oxygen. The TDS (thermal dissociation system) uses a thermal energy input at over 2000 K to thermally dissociate the water. The other cycle, the HTE (high temperature electrolyzer) system, dissociates the water using an electrolyzer operating at high temperature (1300 K) which receives its electrical energy from the fuel cell. The primary advantages of these cycles is that they are basically a no moving parts system, thus having the potential for long life and high reliability, and they have the potential for high thermal efficiency. Both cycles are shown to be classical heat engines with ideal efficiency close to Carnot cycle efficiency. The feasibility of constructing actual cycles is investigated by examining process irreversibilities and device efficiencies for the two types of cycles. The results show that while the processes and devices of the 2000 K TDS exceed current technology limits, the high temperature electrolyzer system appears to be a state-of-the-art technology development. The requirements for very high electrolyzer and fuel cell efficiencies are seen as determining the feasbility of the HTE system, and these high efficiency devices are currently being developed. It is concluded that a proof-of-concept HTE system experiment can and should be conducted.

Process simulation of nuclear-based thermochemical hydrogen production with a copper-chlorine cycle

International Nuclear Information System (INIS)

Chukwu, C.C.; Naterer, G.F.; Rosen, M.A.

2008-01-01

Thermochemical processes for hydrogen production driven by nuclear energy are promising alternatives to existing technologies for large-scale commercial production of hydrogen without fossil fuels. The copper-chlorine (Cu-Cl) cycle, in which water is decomposed into hydrogen and oxygen, is promising for thermochemical hydrogen production in conjunction with a Supercritical Water Cooled Reactor. Here, the cycle efficiency is examined using the Aspen Plus process simulation code. Possible efficiency improvements are discussed. The results are expected to assist the development of a lab-scale cycle demonstration, which is currently being undertaken at University of Ontario Institute of Technology in collaboration with numerous partners. (author)

Integrated gasification and Cu-Cl cycle for trigeneration of hydrogen, steam and electricity

Energy Technology Data Exchange (ETDEWEB)

Aghahosseini, S; Dincer, I; Naterer, G F [University of Ontario, Oshawa, ON (Canada). Institute of Technology

2011-02-15

This paper develops and analyzes an integrated process model of an Integrated Gasification Combined Cycle (IGCC) and a thermochemical copper-chlorine (Cu-Cl) cycle for trigeneration of hydrogen, steam and electricity. The process model is developed with Aspen HYSYS software. By using oxygen instead of air for the gasification process, where oxygen is provided by the integrated Cu-Cl cycle, it is found that the hydrogen content of produced syngas increases by about 20%, due to improvement of the gasification combustion efficiency and reduction of syngas NOx emissions. Moreover, about 60% of external heat required for the integrated Cu-Cl cycle can be provided by the IGCC plant, with minor modifications of the steam cycle, and a slight decrease of IGCC overall efficiency. Integration of gasification and thermochemical hydrogen production can provide significant improvements in the overall hydrogen, steam and electricity output, when compared against the processes each operating separately and independently of each other.

Exergetic life cycle assessment of hydrogen production from renewables

Science.gov (United States)

Granovskii, Mikhail; Dincer, Ibrahim; Rosen, Marc A.

Life cycle assessment is extended to exergetic life cycle assessment and used to evaluate the exergy efficiency, economic effectiveness and environmental impact of producing hydrogen using wind and solar energy in place of fossil fuels. The product hydrogen is considered a fuel for fuel cell vehicles and a substitute for gasoline. Fossil fuel technologies for producing hydrogen from natural gas and gasoline from crude oil are contrasted with options using renewable energy. Exergy efficiencies and greenhouse gas and air pollution emissions are evaluated for all process steps, including crude oil and natural gas pipeline transportation, crude oil distillation and natural gas reforming, wind and solar electricity generation, hydrogen production through water electrolysis, and gasoline and hydrogen distribution and utilization. The use of wind power to produce hydrogen via electrolysis, and its application in a fuel cell vehicle, exhibits the lowest fossil and mineral resource consumption rate. However, the economic attractiveness, as measured by a "capital investment effectiveness factor," of renewable technologies depends significantly on the ratio of costs for hydrogen and natural gas. At the present cost ratio of about 2 (per unit of lower heating value or exergy), capital investments are about five times lower to produce hydrogen via natural gas rather than wind energy. As a consequence, the cost of wind- and solar-based electricity and hydrogen is substantially higher than that of natural gas. The implementation of a hydrogen fuel cell instead of an internal combustion engine permits, theoretically, an increase in a vehicle's engine efficiency of about of two times. Depending on the ratio in engine efficiencies, the substitution of gasoline with "renewable" hydrogen leads to (a) greenhouse gas (GHG) emissions reductions of 12-23 times for hydrogen from wind and 5-8 times for hydrogen from solar energy, and (b) air pollution (AP) emissions reductions of 38

Effect of the Miller cycle on the performance of turbocharged hydrogen internal combustion engines

International Nuclear Information System (INIS)

Luo, Qing-he; Sun, Bai-gang

2016-01-01

Highlights: • The Miller cycle can increase power density for turbocharged hydrogen engines. • The boundaries is limited by the turbocharged system and valve lift. • Broke power and BSFC of using Miller cycle is the best in three technical methods. - Abstract: Hydrogen is a promising energy carrier, and the port fuel injection (PFI) is a fuel-flexible, durable, and relatively cheap method of energy conversion. However, the contradiction of increasing the power density and controlling NOx emissions limits the wide application of PFI hydrogen internal combustion engines. To address this issue, two typical thermodynamic cycles—the Miller and Otto cycles—are studied based on the calculation model proposed in this study. The thermodynamic cycle analyses of the two cycles are compared and results show that the thermal efficiency of the Miller cycle (η_M_i_l_l_e_r) is higher than η_O_t_t_o, when the multiplied result of the inlet pressure and Miller cycle coefficient (δ_Mγ_M) is larger than that of the Otto cycle (i.e., the value of the inlet pressure ratio multiplied by the Miller cycle coefficient is larger than the value of the inlet pressure ratio of the Otto cycle). The results also show that the intake valve closure (IVC) of the Miller cycle is limited by the inlet pressure and valve lift. The two factors show the boundaries of the Miller cycle in increasing the power density of the turbocharged PFI hydrogen engine. The ways of lean burn + Otto cycle (LO), stoichiometric equivalence ratio burn + EGR + Otto cycle (SEO) and Miller cycle in turbocharged hydrogen engine are compared, the results show that the Miller cycle has the highest power density and the lowest BSFC among the three methods at an engine speed of 2800 rpm and NOx emissions below 100 ppm. The brake power of the Miller cycle increases by 37.7% higher than that of the LO and 26.3% higher than that of SEO, when γ_M is 0.7. The BSFC of the Miller cycle decreases by 16% lower than that of

Life cycle assessment of hydrogen production and fuel cell systems

International Nuclear Information System (INIS)

Dincer, I.

2007-01-01

This paper details life cycle assessment (LCA) of hydrogen production and fuel cell system. LCA is a key tool in hydrogen and fuel cell technologies for design, analysis, development; manufacture, applications etc. Energy efficiencies and greenhouse gases and air pollution emissions have been evaluated in all process steps including crude oil and natural gas pipeline transportation, crude oil distillation, natural gas reprocessing, wind and solar electricity generation , hydrogen production through water electrolysis and gasoline and hydrogen distribution and utilization

Investigation of hydrogen bubbles behavior in tungsten by high-flux hydrogen implantation

Science.gov (United States)

Zhao, Jiangtao; Meng, Xuan; Guan, Xingcai; Wang, Qiang; Fang, Kaihong; Xu, Xiaohui; Lu, Yongkai; Gao, Jun; Liu, Zhenlin; Wang, Tieshan

2018-05-01

Hydrogen isotopes retention and bubbles formation are critical issues for tungsten as plasma-facing material in future fusion reactors. In this work, the formation and growing up behavior of hydrogen bubbles in tungsten were investigated experimentally. The planar TEM samples were implanted by 6.0keV hydrogens to a fluence of 3.38 ×1018 H ṡ cm-2 at room temperature, and well-defined hydrogen bubbles were observed by TEM. It was demonstrated that hydrogen bubbles formed when exposed to a fluence of 1.5 ×1018 H ṡ cm-2 , and the hydrogen bubbles grew up with the implantation fluence. In addition, the bubbles' size appeared larger with higher beam flux until saturated at a certain flux, even though the total fluence was kept the same. Finally, in order to understand the thermal annealing effect on the bubbles behavior, hydrogen-implanted samples were annealed at 400, 600, 800, and 1000 °C for 3 h. It was obvious that hydrogen bubbles' morphology changed at temperatures higher than 800 °C.

Hydrogen storage stability of nanoconfined MgH2 upon cycling

DEFF Research Database (Denmark)

Huen, Priscilla; Paskevicius, Mark; Richter, Bo

2017-01-01

It is of utmost importance to optimise and stabilise hydrogen storage capacity during multiple cycles of hydrogen release and uptake to realise a hydrogen-based energy system. Here, the direct solvent-based synthesis of magnesium hydride, MgH2, from dibutyl magnesium, MgBu2, in four different...... issues are highlighted relating to the presence of unwanted gaseous by-products, Mg/MgH2 containment within the scaffold, and the purity of the carbon aerogel scaffold. The results presented provide a research path for future researchers to improve the nanoconfinement process for hydrogen storage...... carbon aerogels with different porosities, i.e., pore sizes, 15 hydrogenations, are conducted for each scaffold...

Controlling hydrogen behavior in light water reactors

International Nuclear Information System (INIS)

Cullingford, H.S.; Edeskuty, F.J.

1981-01-01

In the aftermath of the incident at Three Mile Island Unit 2 (TMI-2), a new and different treatment of the Light Water Reactor (LWR) risks is needed for public safety because of the specific events involving hydrogen generation, transport, and behavior following the core damage. Hydrogen behavior in closed environments such as the TMI-2 containment building is a complex phenomenon that is not fully understood. Hence, an engineering approach is presented for prevention of loss of life, equipment, and environment in case of a large hydrogen generation in an LWR. A six-level defense strategy is described that minimizes the possibility of ignition of released hydrogen gas and otherwise mitigates the consequences of hydrogen release. Guidance is given to reactor manufacturers, utility companies, regulatory agencies, and research organizations committed to reducing risk factors and insuring safety of life, equipment, and environment

Fatigue crack growth behavior in niobium-hydrogen alloys

International Nuclear Information System (INIS)

Lin, M.C.C.; Salama, K.

1997-01-01

Near-threshold fatigue crack growth behavior has been investigated in niobium-hydrogen alloys. Compact tension specimens (CTS) with three hydrogen conditions are used: hydrogen-free, hydrogen in solid solution, and hydride alloy. The specimens are fatigued at a temperature of 296 K and load ratios of 0.05, 0.4, and 0.75. The results at load ratios of 0.05 and 0.4 show that the threshold stress intensity range (ΔK th ) decreases as hydrogen is added to niobium. It reaches a minimum at the critical hydrogen concentration (C cr ), where maximum embrittlement occurs. The critical hydrogen concentration is approximately equal to the solubility limit of hydrogen in niobium. As the hydrogen concentration exceeds C cr , ΔK th increases slowly as more hydrogen is added to the specimen. At load ratio 0.75, ΔK th decreases continuously as the hydrogen concentration is increased. The results provide evidence that two mechanisms are responsible for fatigue crack growth behavior in niobium-hydrogen alloys. First, embrittlement is retarded by hydride transformation--induced and plasticity-induced crack closures. Second, embrittlement is enhanced by the presence of hydrogen and hydride

Life cycle test results of a bipolar nickel hydrogen battery

Science.gov (United States)

Cataldo, R. L.

1985-01-01

A history is given of low Earth orbit (LEO) laboratory test data on a 6.5 ampere-hour bipolar nickel hydrogen battery designed and built at the NASA Lewis Research Center. The bipolar concept is a means of achieving the goal of producing an acceptable battery, of higher energy density, able to withstand the demands of low-Earth-orbit regimes. Over 4100 LEO cycles were established on a ten cell battery. It seems that any perturbation on normal cycling effects the cells performance. Explanations and theories of the battery's behavior are varied and widespread among those closely associated with it. Deep discharging does provide a reconditioning effect and further experimentation is planned in this area. The battery watt-hour efficiency is about 75 percent and the time averaged, discharge voltage is about 1.26 volts for all cells at both the C/4 and LEO rate. Since a significant portion of the electrode capacity has degraded, the LEO cycle discharges are approaching depths of 90 to 100 percent of the high rate capacity. Therefore, the low end-of-discharge voltages occur precipitously after the knee of the discharge curve and is more an indication of electrode capacity and is a lesser indicator of overall cell performance.

Hydrogen Embrittlement Mechanism in Fatigue Behavior of Austenitic and Martensitic Stainless Steels

Directory of Open Access Journals (Sweden)

Sven Brück

2018-05-01

Full Text Available In the present study, the influence of hydrogen on the fatigue behavior of the high strength martensitic stainless steel X3CrNiMo13-4 and the metastable austenitic stainless steels X2Crni19-11 with various nickel contents was examined in the low and high cycle fatigue regime. The focus of the investigations were the changes in the mechanisms of short crack propagation. Experiments in laboratory air with uncharged and precharged specimen and uncharged specimen in pressurized hydrogen were carried out. The aim of the ongoing investigation was to determine and quantitatively describe the predominant processes of hydrogen embrittlement and their influence on the short fatigue crack morphology and crack growth rate. In addition, simulations were carried out on the short fatigue crack growth, in order to develop a detailed insight into the hydrogen embrittlement mechanisms relevant for cyclic loading conditions. It was found that a lower nickel content and a higher martensite content of the samples led to a higher susceptibility to hydrogen embrittlement. In addition, crack propagation and crack path could be simulated well with the simulation model.

[Life cycle assessment of the infrastructure for hydrogen sources of fuel cell vehicles].

Science.gov (United States)

Feng, Wen; Wang, Shujuan; Ni, Weidou; Chen, Changhe

2003-05-01

In order to promote the application of life cycle assessment and provide references for China to make the project of infrastructure for hydrogen sources of fuel cell vehicles in the near future, 10 feasible plans of infrastructure for hydrogen sources of fuel cell vehicles were designed according to the current technologies of producing, storing and transporting hydrogen. Then life cycle assessment was used as a tool to evaluate the environmental performances of the 10 plans. The standard indexes of classified environmental impacts of every plan were gotten and sensitivity analysis for several parameters were carried out. The results showed that the best plan was that hydrogen will be produced by natural gas steam reforming in central factory, then transported to refuelling stations through pipelines, and filled to fuel cell vehicles using hydrogen gas at last.

Effect of long-term hydrogen absorption/desorption cycling on hydrogen storage properties of MmNi3.55Co0.75Mn0.4Al0.3

International Nuclear Information System (INIS)

Li, S.L.; Chen, W.; Chen, D.M.; Yang, K.

2009-01-01

The effect of a long-term hydrogen absorption/desorption cycling up to 2000 cycles on the hydrogen storage properties of MmNi 3.55 Co 0.75 Mn 0.4 Al 0.3 alloy was investigated. The pressure-composition (PC) isotherms for absorption/desorption and absorption kinetics were measured at 338 K, 353 K and 368 K both after initial activation and 2000 cycles. X-ray diffraction analysis revealed that the alloy had a homogeneous hexagonal CaCu 5 type structure and kept this structure even after 2000 hydrogen absorption/desorption cycles. It is found that the absorption/desorption plateau pressures were lowered, the storage capacity and the absorption kinetics were slightly degraded and the hysteresis loss was increased at all the investigated temperatures after 2000 cycles. It is also found that the particle size after 2000 cycles was much smaller compared to that after initial activation. The change of the hydrogen absorption/desorption properties of the alloy after 2000 cycles has been explained by considering the crystal structure, disproportionation property, pulverization of the sample and the impurities in the charging hydrogen employed in cycling

Hydrogen production by thermochemical cycles of water splitting coupled to a solar energy source

International Nuclear Information System (INIS)

Charvin, P.

2007-11-01

The aim of this work is to identify, to test and to estimate new thermochemical cycles able to efficiently produce hydrogen from concentrated solar energy. In fact, the aim is to propose a hydrogen production way presenting a global energetic yield similar to electrolysis, that is to say 20-25%, electrolysis being at the present time the most advanced current process for a clean hydrogen production from water. After a first chapter dealing with the past and present researches on thermochemical cycles, the first step of this study has consisted on a selection of a limited number of thermochemical cycles able to produce great quantities of hydrogen from concentrated solar energy. It has consisted in particular on a review of the thermochemical cycles present in literature, on a first selection from argued criteria, and on an exergetic and thermodynamic analysis of the retained cycles for a first estimation of their potential. The second step of this study deals with the experimental study of all the chemical reactions occurring in the retained cycles. Two different oxides cycles have been particularly chosen and the aims are to demonstrate the feasibility of the reactions, to identify the optimal experimental conditions, to estimate and optimize the kinetics and the chemical yields. The following part of this work deals with the design, the modeling and the test of a solar reactor. A CFD modeling of a high temperature reactor of cavity type allows to identify the main heat losses of the reactor and to optimize the geometry of the cavity. A dynamic modeling of the reactor gives data on its behaviour in transient regime and under a real solar flux. The results of the preliminary experimental results are presented. The last part of this study deals with a process analysis of the thermochemical cycles from the results of the experimental study (experimental conditions, yields...). The matter and energy balances are established in order to estimate the global energetic

Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen flight cells - An update

Science.gov (United States)

Smithrick, John J.; Hall, Stephen W.

1991-01-01

An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells. An update

Science.gov (United States)

Smithrick, John J.; Hall, Stephen W.

1991-01-01

An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells - An update

Science.gov (United States)

Smithrick, John J.; Hall, Stephen W.

1991-01-01

An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.

Microstructural evolution during hydrogen sorption cycling of Mg-FeTi nanolayered composites

Energy Technology Data Exchange (ETDEWEB)

Kalisvaart, W.P., E-mail: pkalisvaart@gmail.com [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, Edmonton, AB, T6G 2V4 (Canada); Kubis, Alan; Danaie, Mohsen; Amirkhiz, Babak Shalchi [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, Edmonton, AB, T6G 2V4 (Canada); Mitlin, David, E-mail: dmitlin@ualberta.ca [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, Edmonton, AB, T6G 2V4 (Canada)

2011-03-15

This paper describes the microstructural evolution of Mg-FeTi mutlilayered hydrogen storage materials during extended cycling. A 28 nm Mg-5 nm FeTi multilayer has comparable performance to a cosputtered material with an equivalent composition (Mg-10%Fe-10%Ti), which is included as a baseline case. At 200 deg. C, the FeTi layers act as a barrier, preventing agglomeration of Mg particles. At 300 deg. C, the initial structure of the multilayer is preserved up to 35 cycles, followed by fracturing of the Mg layers in the in-plane direction and progressive delamination of the FeTi layers as observed by electron microscopy. Concurrently, an increase in the Mg grain size was observed from 32 to 76 nm between cycles 35 and 300. As a result, the absorption kinetics deteriorate with cycling, although 90% of the total capacity is still absorbed within 2 min after as many as 300 cycles. The desorption kinetics, on the other hand, remain rapid and stable, and complete desorption of 4.6 wt.% H is achieved in 1.5 min at ambient desorption pressure. In addition to showing good hydrogen storage performance, multilayers are an excellent model system for studying the relation between microstructure and hydrogen absorption/desorption kinetics.

Microstructural evolution during hydrogen sorption cycling of Mg-FeTi nanolayered composites

International Nuclear Information System (INIS)

Kalisvaart, W.P.; Kubis, Alan; Danaie, Mohsen; Amirkhiz, Babak Shalchi; Mitlin, David

2011-01-01

This paper describes the microstructural evolution of Mg-FeTi mutlilayered hydrogen storage materials during extended cycling. A 28 nm Mg-5 nm FeTi multilayer has comparable performance to a cosputtered material with an equivalent composition (Mg-10%Fe-10%Ti), which is included as a baseline case. At 200 deg. C, the FeTi layers act as a barrier, preventing agglomeration of Mg particles. At 300 deg. C, the initial structure of the multilayer is preserved up to 35 cycles, followed by fracturing of the Mg layers in the in-plane direction and progressive delamination of the FeTi layers as observed by electron microscopy. Concurrently, an increase in the Mg grain size was observed from 32 to 76 nm between cycles 35 and 300. As a result, the absorption kinetics deteriorate with cycling, although 90% of the total capacity is still absorbed within 2 min after as many as 300 cycles. The desorption kinetics, on the other hand, remain rapid and stable, and complete desorption of 4.6 wt.% H is achieved in 1.5 min at ambient desorption pressure. In addition to showing good hydrogen storage performance, multilayers are an excellent model system for studying the relation between microstructure and hydrogen absorption/desorption kinetics.

Hydrogen behavior in light-water reactors

International Nuclear Information System (INIS)

Berman, M.; Cummings, J.C.

1984-01-01

The Three Mile Island accident resulted in the generation of an estimated 150 to 600 kg of hydrogen, some of which burned inside the containment building, causing a transient pressure rise of roughly 200 kPa (2 atm). With this accident as the immediate impetus and the improved safety of reactors as the long-term goal, the nuclear industry and the Nuclear Regulatory Commission initiated research programs to study hydrogen behavior and control during accidents at nuclear plants. Several fundamental questions and issues arise when the hydrogen problem for light-water-reactor plants is examined. These relate to four aspects of the problem: hydrogen production; hydrogen transport, release, and mixing; hydrogen combustion; and prevention or mitigation of hydrogen combustion. Although much has been accomplished, some unknowns and uncertainties still remain, for example, the rate of hydrogen production during a degraded-core or molten-core accident, the rate of hydrogen mixing, the effect of geometrical structures and scale on combustion, flame speeds, combustion completeness, and mitigation-scheme effectiveness. This article discusses the nature and extent of the hydrogen problem, the progress that has been made, and the important unresolved questions

Life Cycle Assessment of Hydrogen Production and Consumption in an Isolated Territory

DEFF Research Database (Denmark)

Zhao, Guangling; Pedersen, Allan Schrøder

2018-01-01

cylinder by road and ferry. The hydrogen is used to provide electricity and heat through fuel cell stacks as well as hydrogen fuel for fuel cell vehicles. In order to evaluate the environmental impacts related to the hydrogen production and utilisation, this work conducts an investigation of the entire...... life cycle of the described hydrogen production, transportation, and utilisation. All the processes related to the equipment manufacture, operation, maintenance, and disposal are considered in this study....

Overview of the Modified SI Cycle to Produce Nuclear Hydrogen Coupled to VHTR

International Nuclear Information System (INIS)

Shin, Youngjoon; Lee, Taehoon; Lee, Kiyoung; Kim, Minhwan

2016-01-01

The steam reforming of methane is one of hydrogen production processes that rely on cheap fossil feedstocks. An overview of the VHTR-based nuclear hydrogen production process with the modified SI cycle has been carried out to establish whether it can be adopted as a feasible technology to produce nuclear hydrogen

Hydrogen behavior in ice condenser containments

Energy Technology Data Exchange (ETDEWEB)

Lundstroem, P.; Hongisto, O. [Power Plant Lab., Helsinki (Finland); Theofanous, T.G. [Univ. of California, Santa Barbara, CA (United States)] [and others

1995-09-01

A new hydrogen management strategy is being developed for the Loviisa ice condenser containment. The strategy relies on containment-wide natural circulations that develop, once the ice condenser doors are forced open, to effectively produce a well-mixed behavior, and a correspondingly slow rise in hydrogen concentration. Levels can then be kept low by a distributed catalytic recombiner system, and (perhaps) an igniter system as a backup, while the associated energy releases can be effectively dissipated in the ice bed. Verification and fine-tuning of the approach is carried out experimentally in the VICTORIA facility and by associated scaling/modelling studies. VICTORIA represents an 1/15th scale model of the Loviisa containment, hydrogen is simulated by helium, and local concentration measurements are obtained by a newly developed instrument specifically for this purpose, called SPARTA. This paper is focused on experimental results from several key experiments that provide a first delineation of key behaviors.

Technical project of complex fast cycle heat treatment of hydrogenous coal preparation

OpenAIRE

Moiseev, V. A.; Andrienko, V. G.; Pileckij, V. G.; Urvancev, A. I.; Gvozdyakov, Dmitry Vasilievich; Gubin, Vladimir Evgenievich; Matveev, Aleksandr Sergeevich; Savostiyanova, Ludmila Viktorovna

2015-01-01

Problems of heat-treated milled hydrogenous coal preparation site creation in leading fast cycle heat treatment complex were considered. Conditions for effective use of electrostatic methods of heat-treated milled hydrogenous coal preparation were set. Technical project of heat treatment of milled hydrogenous coal preparation site was developed including coupling of working equipment complex on fast heat treatment and experimental samples of equipment being designed for manufacturing. It was ...

BEHAVIOR OF THERMAL SPRAY COATINGS AGAINST HYDROGEN ATTACK

OpenAIRE

Vargas, Fabio; Latorre, Guillermo; Uribe, Iván

2003-01-01

The behavior of nickel and chrome alloys applied as thermal spray coatings to be used as protection against embrittlement by hydrogen is studied. Coatings were applied on a carbon steel substrate, under conditions that allow obtain different crystalline structures and porosity levels, in order to determine the effect of these variables on the hydrogen permeation kinetics and as a protection means against embrittlement caused this element. In order to establish behaviors as barriers and protec...

Thermoeconomic analysis of a copper-chlorine thermochemical cycle for nuclear-based hydrogen production

International Nuclear Information System (INIS)

Orhan, Mehmet F.; Dincer, Ibrahim; Rosen, Marc A.

2010-01-01

Thermochemical water splitting with a copper-chlorine (Cu-Cl) cycle is a promising process that could be linked with nuclear reactors to decompose water into its constituents, oxygen and hydrogen, through intermediate copper and chlorine compounds. In this paper, a comprehensive exergoeconomic analysis of the Cu-Cl cycle is reported to evaluate the production costs as a function of the amount and quality of the energy used for hydrogen production, as well as the costs of the exergy losses and the exergoeconomic improvement potential of the equipment used in the process. An additional objective is to determine changes in the design parameters of the Cu-Cl cycle that improve the cost effectiveness of the overall system. (orig.)

Preliminary tension effect on low-cycle fatigue of 40Kh13 steel in gaseous hydrogen

International Nuclear Information System (INIS)

Romaniv, A.N.

1984-01-01

Comparative bending tests of specimens deformed by tension at 65, 18 and 30% in hydrogen and vacuum were accomplished to reveal the effect of preliminary tension on low-cycle fatigue strength of 40Kh13 martensitic steel. It was found that small amounts of preliminary strains induced a considerable decrease in low-cycle durability in vacuum and hydrogen which was connected with developing defects arising at the early stages of plastic deformation. A rather high degree of preliminary tension promoted steel homogenization, hydrogen embrittlement decrease and service behaviour improvement

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cell - Update II

Science.gov (United States)

Smithrick, John J.; Hall, Stephen W.

1992-01-01

An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent KOH electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel (IPV) nickel-hydrogen cells has been previously reported. The cycle life of boiler plate cells containing 26 percent potassium hydroxide (KOH) electrolyte was about 40,000 LEO cycles, compared to 3500 cycles for cells containing 31 percent KOH. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min discharge (2X normal rate). The depth-of-discharge was 80 percent. Six 48-Ah Hughes recirculation design IPV nickel-hydrogen flight battery cells are being evaluated. Three of the cells contain 26 percent KOH (test cells), and three contain 31 percent KOH (control cells). They are undergoing real time LEO cycle life testing. The cycle regime is a 90-min LEO orbit consisting of a 54-min charge followed by a 36-min discharge. The depth-of-discharge is 80 percent. The cell temperature is maintained at 10 C. The three 31 percent KOH cells failed (cycles 3729, 4165, and 11355). One of the 26 percent KOH cells failed at cycle 15314. The other two 26 percent KOH cells were cycled for over 16,000 cycles during the continuing test.

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

Directory of Open Access Journals (Sweden)

Dudek Michał

2016-01-01

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

Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power

International Nuclear Information System (INIS)

Brown, L.C.; Funk, J.F.; Showalter, S.K.

1999-01-01

OAK B188 Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power There is currently no large scale, cost-effective, environmentally attractive hydrogen production process, nor is such a process available for commercialization. Hydrogen is a promising energy carrier, which potentially could replace the fossil fuels used in the transportation sector of our economy. Fossil fuels are polluting and carbon dioxide emissions from their combustion are thought to be responsible for global warming. The purpose of this work is to determine the potential for efficient, cost-effective, large-scale production of hydrogen utilizing high temperature heat from an advanced nuclear power station. Almost 800 literature references were located which pertain to thermochemical production of hydrogen from water and over 100 thermochemical watersplitting cycles were examined. Using defined criteria and quantifiable metrics, 25 cycles have been selected for more detailed study

Heat pump cycle by hydrogen-absorbing alloys to assist high-temperature gas-cooled reactor in producing hydrogen

International Nuclear Information System (INIS)

Satoshi, Fukada; Nobutaka, Hayashi

2010-01-01

A chemical heat pump system using two hydrogen-absorbing alloys is proposed to utilise heat exhausted from a high-temperature source such as a high-temperature gas-cooled reactor (HTGR), more efficiently. The heat pump system is designed to produce H 2 based on the S-I cycle more efficiently. The overall system proposed here consists of HTGR, He gas turbines, chemical heat pumps and reaction vessels corresponding to the three-step decomposition reactions comprised in the S-I process. A fundamental research is experimentally performed on heat generation in a single bed packed with a hydrogen-absorbing alloy that may work at the H 2 production temperature. The hydrogen-absorbing alloy of Zr(V 1-x Fe x ) 2 is selected as a material that has a proper plateau pressure for the heat pump system operated between the input and output temperatures of HTGR and reaction vessels of the S-I cycle. Temperature jump due to heat generated when the alloy absorbs H 2 proves that the alloy-H 2 system can heat up the exhaust gas even at 600 deg. C without any external mechanical force. (authors)

Hydrogen production at <550 C using a low temperature thermochemical cycle

International Nuclear Information System (INIS)

Lewis, M.A.; Serban, M.; Basco, J.K.

2004-01-01

A Department of Energy goal is to identify new technologies for producing hydrogen cost effectively without greenhouse gas emissions. Thermochemical cycles are one of the potential options under investigation. Thermochemical cycles consist of a series of reactions in which water is thermally decomposed and all other chemicals are recycled. Only heat and water are consumed. However, most thermochemical cycles require process heat at temperatures of 850-900 deg C. Argonne National Laboratory is developing low temperature cycles designed for lower temperature heat, 500-550 deg C, which is more readily available. For this temperature region, copper-chlorine (Cu-Cl) cycles are the most promising cycle. Several Cu-Cl cycles have been examined in the laboratory and the most promising cycle has been identified. Proof-of-principle experiments are nearly complete. A preliminary assessment of cycle efficiency is promising. Details of the experiments and efficiency calculations are discussed. (author)

Carbon dioxide emission in hydrogen production technology from coke oven gas with life cycle approach

Directory of Open Access Journals (Sweden)

Burmistrz Piotr

2016-01-01

Full Text Available The analysis of Carbon Footprint (CF for technology of hydrogen production from cleaned coke oven gas was performed. On the basis of real data and simulation calculations of the production process of hydrogen from coke gas, emission indicators of carbon dioxide (CF were calculated. These indicators are associated with net production of electricity and thermal energy and direct emission of carbon dioxide throughout a whole product life cycle. Product life cycle includes: coal extraction and its transportation to a coking plant, the process of coking coal, purification and reforming of coke oven gas, carbon capture and storage. The values were related to 1 Mg of coking blend and to 1 Mg of the hydrogen produced. The calculation is based on the configuration of hydrogen production from coke oven gas for coking technology available on a commercial scale that uses a technology of coke dry quenching (CDQ. The calculations were made using ChemCAD v.6.0.2 simulator for a steady state of technological process. The analysis of carbon footprint was conducted in accordance with the Life Cycle Assessment (LCA.

KOH concentration effect on the cycle life of nickel-hydrogen cells

Science.gov (United States)

Lim, H. S.; Verzwyvelt, S. A.

1985-01-01

Effects of KOH concentration on the cycle life of a sintered-type nickel electrode were studied in a boiler plate nickel-hydrogen cell at 23 C using an accelerated 45-min cycle regime at 80 percent depth of discharge. The cycle life improved greatly as the KOH concentration decreased, although the initial capacity of the cell decreased slightly. The cycle life improved by a factor of two or more when the KOH concentration was reduced from 36 to 31 percent and by a similar factor from reductions of 31 to 26 percent. For many applications, this life improvement may outweigh the initial capacity decrease.

A study on hydrogen adsorption behaviors of open-tip carbon nanocones

International Nuclear Information System (INIS)

Liao Mingliang

2012-01-01

Hydrogen adsorption behaviors of single-walled open-tip (tip-truncated) carbon nanocones (CNCs) with apex angles of 19.2° at temperatures of 77 and 300 K were investigated by the molecular dynamics simulations. Four nanomaterials (including three CNCs with different dimensions and a reference CNT) were analyzed to examine the hydrogen adsorption behaviors and influences of cone sharpness on the behaviors of the CNCs. Physisorption of hydrogen molecules could be observed from the distribution pattern of the hydrogen molecules adsorbed on the nanomaterials. Because of the cone geometry effect, the open-tip CNCs could have larger storage weight percentage and less desorption of hydrogen molecules (caused by the temperature growth) on their outer surfaces, as compared with those of the reference CNT. The hydrogen molecules inside the CNCs and the reference CNT, however, were noted to have similar desorption behaviors owing to the confinement effects from the structures of the nanomaterials. In addition, the sharper CNC could have higher storage weight percentage but the cone sharpness does not have evident enhancement in the average adsorption energy of the CNC. Combination of confinement and repulsion effects existing near the tip region of the CNC would be responsible for the non-enhancement feature.

Low cycle fatigue life of two nickel-base casting alloys in a hydrogen environment

International Nuclear Information System (INIS)

Cooper, R.A.

1976-01-01

Results of low cycle fatigue tests on alloy Mar-M-246 and Inconel 713 are presented. Based on the limited data, it was concluded that the Mar-M-246 material had a cyclic life in hydrogen that averaged three times higher than the alloy 713LC material for similar strain ranges. The hydrogen environment reduced life for both materials. The life reduction was more than an order of magnitude for the 713LC material. Porosity content of the cast specimens was as expected and was an important factor governing low cycle fatigue life

High stability of palladium/kieselguhr composites during absorption/desorption cycling for hydrogen isotope separation

Energy Technology Data Exchange (ETDEWEB)

Lei, Yang, E-mail: lei.y@outlook.com; Liu, Xiaopeng; Li, Shuo; Jiang, Lijun; Zhang, Chao; Li, Shuai; He, Di; Wang, Shumao

2016-12-15

Highlights: • Pd/K composites with as high as 57 wt.% of Pd have been successfully prepared. • Palladium particles can be effectively packed into the pores of kieselguhr substrates. • Variation of heat-treatment temperatures hardly affect hydrogen absorption capacity and hydrogen saturation time of the Pd/K. • Anti-pulverization property of Pd/K can be improved by packing palladium into the kieselguhr internal pores and heating at 1300 °C. - Abstract: Palladium/kieselguhr (Pd/K) composites with 57 wt.% of Pd were prepared by an improved dipping and thermal decomposition method and heated at elevated temperature to reduce breakdown during hydrogenation-dehydrogenation cycles. The hydrogen absorption kinetic properties of the samples heated at different temperatures were tested under the condition of 20 °C with 100 kPa hydrogen pressure. The 1300 °C heated Pd/K composites were repeated up to 4010 absorption and desorption cycles at temperature ranges between −40 °C and 200 °C. The results show that the phase structure, hydrogen absorption capacity and hydrogen saturation time of the Pd/K were not affected by the change of heat-treated temperatures. And after heat treatment at 1300 °C, the Pd/K particles were strengthened and fraction of larger than 80 mesh were as high as 93.4%.

Thermodynamic Cycle and CFD Analyses for Hydrogen Fueled Air-breathing Pulse Detonation Engines

Science.gov (United States)

Povinelli, Louis A.; Yungster, Shaye

2002-01-01

This paper presents the results of a thermodynamic cycle analysis of a pulse detonation engine (PDE) using a hydrogen-air mixture at static conditions. The cycle performance results, namely the specific thrust, fuel consumption and impulse are compared to a single cycle CFD analysis for a detonation tube which considers finite rate chemistry. The differences in the impulse values were indicative of the additional performance potential attainable in a PDE.

Buoyant Unstable Behavior of Initially Spherical Lean Hydrogen-Air Premixed Flames

Directory of Open Access Journals (Sweden)

Zuo-Yu Sun

2014-07-01

Full Text Available Buoyant unstable behavior in initially spherical lean hydrogen-air premixed flames within a center-ignited combustion vessel have been studied experimentally under a wide range of pressures (including reduced, normal, and elevated pressures. The experimental observations show that the flame front of lean hydrogen-air premixed flames will not give rise to the phenomenon of cellular instability when the equivalence ratio has been reduced to a certain value, which is totally different from the traditional understanding of the instability characteristics of lean hydrogen premixed flames. Accompanied by the smoothened flame front, the propagation mode of lean hydrogen premixed flames transitions from initially spherical outwardly towards upwardly when the flames expand to certain sizes. To quantitatively investigate such buoyant instability behaviors, two parameters, “float rate (ψ” and “critical flame radius (Rcr”, have been proposed in the present article. The quantitative results demonstrate that the influences of initial pressure (Pint on buoyant unstable behaviors are different. Based on the effects of variation of density difference and stretch rate on the flame front, the mechanism of such buoyant unstable behaviors has been explained by the competition between the stretch force and the results of gravity and buoyancy, and lean hydrogen premixed flames will display buoyant unstable behavior when the stretch effects on the flame front are weaker than the effects of gravity and buoyancy.

Hydrogen production using the sulfur-iodine cycle coupled to a VHTR: An overview

International Nuclear Information System (INIS)

Vitart, X.; Le Duigou, A.; Carles, P.

2006-01-01

The sulfur-iodine thermo-chemical cycle is considered to be one of the most promising routes for massive hydrogen production, using high temperature heat from a Generation IV VHTR. We propose here a brief overview of the main questions raised by this cycle, along with the general lines of French CEA's program

Assessing the Life-Cycle Performance of Hydrogen Production via Biofuel Reforming in Europe

Directory of Open Access Journals (Sweden)

Ana Susmozas

2015-06-01

Full Text Available Currently, hydrogen is mainly produced through steam reforming of natural gas. However, this conventional process involves environmental and energy security concerns. This has led to the development of alternative technologies for (potentially green hydrogen production. In this work, the environmental and energy performance of biohydrogen produced in Europe via steam reforming of glycerol and bio-oil is evaluated from a life-cycle perspective, and contrasted with that of conventional hydrogen from steam methane reforming. Glycerol as a by-product from the production of rapeseed biodiesel and bio-oil from the fast pyrolysis of poplar biomass are considered. The processing plants are simulated in Aspen Plus® to provide inventory data for the life cycle assessment. The environmental impact potentials evaluated include abiotic depletion, global warming, ozone layer depletion, photochemical oxidant formation, land competition, acidification and eutrophication. Furthermore, the cumulative (total and non-renewable energy demand is calculated, as well as the corresponding renewability scores and life-cycle energy balances and efficiencies of the biohydrogen products. In addition to quantitative evidence of the (expected relevance of the feedstock and impact categories considered, results show that poplar-derived bio-oil could be a suitable feedstock for steam reforming, in contrast to first-generation bioglycerol.

Bibliographic Review about Solar Hydrogen Production Through Thermochemical Cycles; Revision Bibliografica sobre la Produccion de Hidrogeno Solar Mediante Ciclos Termoquimicos

Energy Technology Data Exchange (ETDEWEB)

Fernandez Saavedra, R.

2007-12-28

This report presents a summary of the different thermical processes used to obtain hydrogen through solar energy, paying more attention to the production of hydrogen from water through thermochemical cycles. In this aspect, it is briefly described the most interesting thermochemical cycles, focusing on thermochemical cycles based on oxides. (Author) 25 refs.

Bibliographic Review about Solar Hydrogen Production Through Thermochemical Cycles; Revision Bibliografica sobre la Produccion de Hidrogeno Solar Mediante Ciclos Termoquimicos

Energy Technology Data Exchange (ETDEWEB)

Fernandez Saavedra, R.

2008-08-06

This report presents a summary of the different thermical processes used to obtain hydrogen through solar energy, paying more attention to the production of hydrogen from water through thermochemical cycles. In this aspect, it is briefly y described the most interesting thermochemical cycles, focusing on thermochemical cycles based on oxides. (Author) 25 refs.

The calculation of specific heats for some important solid components in hydrogen production process based on CuCl cycle

Directory of Open Access Journals (Sweden)

Avsec Jurij

2014-01-01

Full Text Available Hydrogen is one of the most promising energy sources of the future enabling direct production of power and heat in fuel cells, hydrogen engines or furnaces with hydrogen burners. One of the last remainder problems in hydrogen technology is how to produce a sufficient amount of cheap hydrogen. One of the best options is large scale thermochemical production of hydrogen in combination with nuclear power plant. copper-chlorine (CuCl cycle is the most promissible thermochemical cycle to produce cheap hydrogen.This paper focuses on a CuCl cycle, and the describes the models how to calculate thermodynamic properties. Unfortunately, for many components in CuCl cycle the thermochemical functions of state have never been measured. This is the reason that we have tried to calculate some very important thermophysical properties. This paper discusses the mathematical model for computing the thermodynamic properties for pure substances and their mixtures such as CuCl, HCl, Cu2OCl2 important in CuCl hydrogen production in their fluid and solid phase with an aid of statistical thermodynamics. For the solid phase, we have developed the mathematical model for the calculation of thermodynamic properties for polyatomic crystals. In this way, we have used Debye functions and Einstein function for acoustical modes and optical modes of vibrations to take into account vibration of atoms. The influence of intermolecular energy we have solved on the basis of Murnaghan equation of state and statistical thermodynamics.

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells-update 2

Science.gov (United States)

Smithrick, John J.; Hall, Stephen W.

1991-01-01

An update of validation test results confirming the breakthrough in low earth orbit (LEO) cycle life of nickel-hydrogen cells containing 26 percent KOH electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel (IPV nickel-hydrogen cells has been previously reported. The cycle life of boiler plate cells containing 26 percent potassium hydroxide (KOH) electrolyte was about 40 000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH. This test was conducted at Hughes Aircraft Company under a NASA Lewis contract. The purpose was to investigate the effect of KOH concentration on cycle life. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min discharge (2x normal rate). The depth of discharge (DOD) was 80 percent. The cell temperature was maintained at 23 C. The boiler plate test results are in the process of being validated using flight hardware and real time LEO test at the Naval Weapons Support Center (NWSC), Crane, Indiana under a NASA Lewis Contract. Six 48 Ah Hughes recirculation design IPV nickel-hydrogen flight battery cells are being evaluated. Three of the cells contain 26 percent KOH (test cells), and three contain 31 percent KOH (control cells). They are undergoing real time LEO cycle life testing. The cycle regime is a 90-min LEO orbit consisting of a 54-min charge followed by a 36-min discharge. The depth-of-discharge is 80 percent. The cell temperature is maintained at 10 C. The three 31 percent KOH cells failed (cycles 3729, 4165, and 11355). One of the 26 percent KOH cells failed at cycle 15314. The other two 26 percent KOH cells were cycled for over 16600 cycles during the continuing test.

Life cycle costs for the optimized production of hydrogen and biogas from microalgae

International Nuclear Information System (INIS)

Meyer, Markus A.; Weiss, Annika

2014-01-01

Despite the known advantages of microalgae compared with other biomass providers or fossil fuels, microalgae are predominately produced for high-value products. Economic constraints might limit the commercial energetic use of microalgae. Therefore, we identify the LCCs (life cycle costs) and economic hot spots for photoautotrophic hydrogen generation from photoautotrophically grown Chlamydomonas reinhardtii in a novel staggered PBR (photobioreactor) and the anaerobic digestion of the residual biomass to obtain biogas. The novel PBR aims at minimizing energy consumption for mixing and aeration and at optimizing the light conditions for algal growth. The LCCs per MJ amounted to 12.17 Euro for hydrogen and 0.99 Euro for biogas in 2011 for Germany. Market prices per MJ of 0.02 Euro for biogas and 0.04 Euro for hydrogen are considerably exceeded. Major contributors to operating costs, about 70% of total LCCs, are personnel and overhead costs. The investment costs consist to about 92% of those for the PBR with a share of 61% membrane costs. The choice of Madrid as another production location with higher incident solar irradiation and lower personnel costs reduces LCCs by about 40%. Projecting LCCs to 2030 with experience curves, the LCCs still exceed future market prices. - Highlights: • Life cycle cost assessment of hydrogen and biogas from microalgae in a novel photobioreactor. • Current and future (2030) economically viable production unlikely in Germany. • Personnel and photobioreactor costs are major cost drivers. • Changing the production location may significantly reduce the life cycle costs

Assessing the Life-Cycle Performance of Hydrogen Production via Biofuel Reforming in Europe

OpenAIRE

Susmozas, Ana; Iribarren, Diego; Dufour, Javier

2015-01-01

Currently, hydrogen is mainly produced through steam reforming of natural gas. However, this conventional process involves environmental and energy security concerns. This has led to the development of alternative technologies for (potentially) green hydrogen production. In this work, the environmental and energy performance of biohydrogen produced in Europe via steam reforming of glycerol and bio-oil is evaluated from a life-cycle perspective, and contrasted with that of conventional hydroge...

The effect of hydrogen on the multiaxial stress-strain behavior of titanium tubing

International Nuclear Information System (INIS)

Lentz, C.W.; Hecker, S.S.; Koss, D.A.; Stout, M.G.

1983-01-01

The influence of internal hydrogen on the multiaxial stress-strain behavior of commercially pure titanium has been studied. Thin-walled specimens containing either 20 or 1070 ppm hydrogen were tested at constant stress ratios in combined tension and internal pressure. Hydrogen lowers the yield strength but has no significant effect on strain hardening behavior at strains epsilon greater than or equal to 0.02. Thus, hydrogen embrittlement under plain strain or equibiaxial loading is not a consequence of changes of flow behavior. The yielding behavior is described well by Hill's quadratic yield criterion. As measured mechanically and pole figure analysis, the plastic anisotropy changes with deformation in a manner which depends on stress state. A strain dependent, texture-induced strengthening effect in equibiaxial tension an enhanced strain hardening rate

Thermodynamic of the associated cycle and application to the assembly of thermochemical iodine sulphur cycle and a nuclear engine for the hydrogen production

International Nuclear Information System (INIS)

Dumont, Y.

2008-01-01

This thesis is devoted to the design of an assembly of a hydrogen production process by the thermochemical iodine-sulphur cycle and a nuclear reactor. The suggested coupling network uses a power cycle which produces a work which is directly used for the heat pump running. The purpose of this thermodynamic cycle association is to recover the rejected energy at low temperature of a process to provide the energy needs of this same process at high temperature. This association is applied to the studied coupling. The construction of the energy distribution network is designed by the pinch analysis. In the case of a conventional coupling, the efficiency of hydrogen production is 22.0%. By integrating the associated cycles into the coupling, the efficiency of production is 42.6%. The exergetic efficiency, representative of the energy using quality, increases from 58.7% to 85.4%. (author) [fr

Molecular dynamics simulation of effect of hydrogen atoms on crack propagation behavior of α-Fe

Energy Technology Data Exchange (ETDEWEB)

Song, H.Y., E-mail: gsfshy@sohu.com; Zhang, L.; Xiao, M.X.

2016-12-16

The effect of the hydrogen concentration and hydrogen distribution on the mechanical properties of α-Fe with a pre-existing unilateral crack under tensile loading is investigated by molecular dynamics simulation. The results reveal that the models present good ductility when the front region of crack tip has high local hydrogen concentration. The peak stress of α-Fe decreases with increasing hydrogen concentration. The studies also indicate that for the samples with hydrogen atoms, the crack propagation behavior is independent of the model size and boundaries. In addition, the crack propagation behavior is significantly influenced by the distribution of hydrogen atoms. - Highlights: • The distribution of hydrogen plays a critical role in the crack propagation. • The peak stress decrease with the hydrogen concentration increasing. • The crack deformation behavior is disclosed and analyzed.

A TEM based study of the microstructure during room temperature and low temperature hydrogen storage cycling in MgH2 promoted by Nb–V

International Nuclear Information System (INIS)

Tan Xuehai; Zahiri, Beniamin; Holt, Chris M.B.; Kubis, Alan; Mitlin, David

2012-01-01

Magnesium hydride combined with a new bimetallic Nb–V catalyst displays remarkably rapid and stable low temperature (200 °C) hydrogen storage kinetics, even after 500 full volumetric absorption/desorption cycles. The system is also able to fairly rapidly absorb hydrogen at room temperature at a pressure of 1 bar. This unprecedented absorption behavior was demonstrated for 20 cycles. We employed extensive cryo-stage transmission electron microscopy (TEM) analysis on fully and partially sorbed materials to provide insight into the rapid Mg to MgH 2 phase transformation. After extended cycling of what was initially a 1.5 μm thick fully dense alloy film, the sample structure becomes analogous to that of a weakly agglomerated nanocomposite powder. The cycled Mg–V–Nb structure consists of a dense distribution of catalytic Nb–V nanocrystallites covering the surfaces of larger Mg and MgH 2 particles. The partially absorbed 20 °C and 200 °C microstructures both show this morphology. TEM results combined with Johnson–Mehl–Avrami-type kinetic analysis point to the surface catalyst distribution and stability against coarsening as being a key influence on the two-stage hydriding kinetics. Remarkably, the mean size of the Nb 0.5 V 0.5 H nanocrystallites stays essentially invariant throughout cycling; it is 3 nm after 45 cycles and 4 nm after 500 cycles. A mechanistic description is provided for the cycling-induced microstructural evolution in the ternary alloy as well as in the binary baselines.

Clean energy and hydrogen for oil sands development with CANDU SCWR nuclear reactors and Cu-Cl cycles

International Nuclear Information System (INIS)

Wang, Z.L.; Naterer, G.F.; Gabriel, K.S.

2010-01-01

In this paper, the unique capabilities and advantages of SCWR technology for cleaner oil sands development are discussed from two perspectives: lower temperature steam generation by supercritical water for steam assisted gravity drainage (SAGD), and hydrogen production for oil sands upgrading by coupling SCWR with the thermochemical copper-chlorine (Cu-Cl) cycle. The heat requirements for bitumen extraction from the oil sands and the hydrogen requirements for bitumen upgrading are evaluated. A conceptual layout of SCWR coupled with oil sands development is presented. The reduction of CO 2 emissions due to the use of SCWR and thermo chemical hydrogen production cycle is also analyzed. (author)

Preparation of platinum-decorated porous graphite nanofibers, and their hydrogen storage behaviors.

Science.gov (United States)

Kim, Byung-Joo; Lee, Young-Seak; Park, Soo-Jin

2008-02-15

In this work, the hydrogen storage behaviors of porous graphite nanofibers (GNFs) decorated by Pt nanoparticles were investigated. The Pt nanoparticles were introduced onto the GNF surfaces using a well-known chemical reduction method. We investigated the hydrogen storage capacity of the Pt-doped GNFs for the platinum content range of 1.3-7.5 mass%. The microstructure of the Pt/porous GNFs was characterized by X-ray diffraction and transmission electron microscopy. The hydrogen storage behaviors of the Pt/GNFs were studied using a PCT apparatus at 298 K and 10 MPa. It was found that amount of hydrogen stored increased with increasing Pt content to 3.4 mass%, and then decreased. This result indicates that the hydrogen storage capacity of porous carbons is based on both their metal content and dispersion rate.

Developing Behavioral Fluency with Movement Cycles Using SAFMEDS

Science.gov (United States)

Kubina, Richard M., Jr.; Yurich, Kirsten K. L.; Durica, Krina C.; Healy, Nora M.

2016-01-01

The Precision Teaching term "movement cycle" refers to a behavior with a clearly observable movement and a distinct beginning and end. The present experiment examined whether behavior analysts and special education teachers could become fluent identifying movement cycles. A frequency-building intervention called SAFMEDS, an acronym for…

Influence of hydrogen on high cycle fatigue of polycrystalline vanadium

International Nuclear Information System (INIS)

Chung, D.W.; Lee, K.S.; Stoloff, N.S.

1977-02-01

The room temperature fatigue behavior of several polycrystalline V-H 2 alloys is described. Hydrogen extends the life of unnotched vanadium but has a deleterious effect in notched materials. Crack propagation data are correlated with tensile yield stress and cyclic strain hardening data

Microstructure and kinetics evolution in MgH2–TiO2 pellets after hydrogen cycling

International Nuclear Information System (INIS)

Mirabile Gattia, D.; Di Girolamo, G.; Montone, A.

2014-01-01

Highlights: • MgH 2 was ball milled with TiO 2 anatase phase and expanded graphite to prepare pellets. • Different pellets have been prepared at different compression load. • Pellets were repeatedly cycled under hydrogen pressure to simulate tank exercise and verify their stability. • The compression load highly affects the stability of the pellets to cycling. • Microstructural evolution of the particles due to cycling have been observed. - Abstract: The interest in Mg-based hydrides for solid state hydrogen storage is associated to their capability to reversibly absorb and desorb large amounts of hydrogen. In this work MgH 2 powder with 5 wt.% TiO 2 was ball milled for 10 h. The as-milled nanostructured powder was enriched with 5 wt.% of Expanded Natural Graphite (ENG) and then compacted in cylindrical pellets by cold pressing using different loads. Both the powder and the pellets were subjected to kinetic and thermodynamic tests using a Sievert’s type gas reaction controller, in order to study the microstructural and kinetic changes which took place during repeated H 2 absorption and desorption cycles. The pellets exhibited good kinetic performance and durability, even if the pressure of compaction revealed to be an important parameter for their mechanical stability. Scanning Electron Microscopy observations of as-prepared and cycled pellets were carried out to investigate the evolution of their microstructure. In turn the phase composition before and after cycling was analyzed by X-ray diffraction

Measuring the environmental benefits of hydrogen transportation fuel cycles under uncertainty about external costs

International Nuclear Information System (INIS)

Chernyavs'ka, Liliya; Gulli, Francesco

2010-01-01

In this paper, we attempt to measure the environmental benefits of hydrogen deployment in the transportation sector. We compare the hydrogen pathways to the conventional transportation fuel cycles in terms of external costs, estimated using the results of the most accurate methodologies available in this field. The central values of performed analysis bring us ambiguous results. The external cost of the best conventional solution ('oil to diesel hybrid internal-combustion engine') in some cases is just higher and in others just lower than that of the best fossil fuel to hydrogen solution ('natural gas to hydrogen fuel cell'). Nevertheless, by accounting for the uncertainty about external costs, we are able to remove this ambiguity highlighting that the hydrogen pathway provides significant environmental benefits ,especially in densely populated areas, assuming 100% city driving.

Solar Metal Sulfate-Ammonia Based Thermochemical Water Splitting Cycle for Hydrogen Production

Science.gov (United States)

Huang, Cunping (Inventor); T-Raissi, Ali (Inventor); Muradov, Nazim (Inventor)

2014-01-01

Two classes of hybrid/thermochemical water splitting processes for the production of hydrogen and oxygen have been proposed based on (1) metal sulfate-ammonia cycles (2) metal pyrosulfate-ammonia cycles. Methods and systems for a metal sulfate MSO.sub.4--NH3 cycle for producing H2 and O2 from a closed system including feeding an aqueous (NH3)(4)SO3 solution into a photoctalytic reactor to oxidize the aqueous (NH3)(4)SO3 into aqueous (NH3)(2)SO4 and reduce water to hydrogen, mixing the resulting aqueous (NH3)(2)SO4 with metal oxide (e.g. ZnO) to form a slurry, heating the slurry of aqueous (NH4)(2)SO4 and ZnO(s) in the low temperature reactor to produce a gaseous mixture of NH3 and H2O and solid ZnSO4(s), heating solid ZnSO4 at a high temperature reactor to produce a gaseous mixture of SO2 and O2 and solid product ZnO, mixing the gaseous mixture of SO2 and O2 with an NH3 and H2O stream in an absorber to form aqueous (NH4)(2)SO3 solution and separate O2 for aqueous solution, recycling the resultant solution back to the photoreactor and sending ZnO to mix with aqueous (NH4)(2)SO4 solution to close the water splitting cycle wherein gaseous H2 and O2 are the only products output from the closed ZnSO4--NH3 cycle.

Effect of storage and LEO cycling on manufacturing technology IPV nickel-hydrogen cells

Science.gov (United States)

Smithrick, John J.

1987-01-01

Yardney Manufacturing Technology (MANTECH) 50 A-hr space weight individual pressure vessel nickel-hydrogen cells were evaluated. This consisted of investigating: the effect of storage and charge/discharge cycling on cell performance. For the storage test the cells were precharged with hydrogen, by the manufacturer, to a pressure of 14.5 psia. After undergoing activation and acceptance tests, the cells were discharged at C/10 rate (5A) to 0.1 V or less. The terminals were then shorted. The cells were shipped to NASA Lewis Research Center where they were stored at room temperature in the shorted condition for 1 year. After storage, the acceptance tests were repeated at NASA Lewis. A comparison of test results indicate no significant degradation in electrical performance due to 1 year storage. For the cycle life test the regime was a 90 minute low earth orbit at deep depths of discharge (80 and 60 percent). At the 80 percent DOD the three cells failed on the average at cycle 741. Failure for this test was defined to occur when the cell voltage degraded to 1 V prior to completion of the 35 min discharge. The DOD was reduced to 60 percent. The cycle life test was continued.

Materials considerations for the coupling of thermochemical hydrogen cycles to tandem mirror reactors

International Nuclear Information System (INIS)

Krikorian, O.H.

1980-01-01

Candidate materials are discussed and initial choices made for the critical elements in a liquid Li-Na Cauldron Tandem Mirror blanket and the General Atomic Sulfur-Iodine Cycle for thermochemical hydrogen production. V and Ti alloys provide low neutron activation, good radiation damage resistance, and good chemical compatibility for the Cauldron design. Aluminide coated In-800H and siliconized SiC are materials choices for heat exchanger components in the thermochemical cycle interface

Hydrogen storage in binary and ternary Mg-based alloys: A comprehensive experimental study

Energy Technology Data Exchange (ETDEWEB)

Kalisvaart, W.P.; Harrower, C.T.; Haagsma, J.; Zahiri, B.; Luber, E.J.; Ophus, C.; Mitlin, D. [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, T6G 2V4, Edmonton, Alberta (Canada); Poirier, E.; Fritzsche, H. [National Research Council Canada, SIMS, Canadian Neutron Beam Centre, Chalk River Laboratories, Chalk River, Ontario, K0J 1J0 (Canada)

2010-03-15

This study focused on hydrogen sorption properties of 1.5 {mu}m thick Mg-based films with Al, Fe and Ti as alloying elements. The binary alloys are used to establish as baseline case for the ternary Mg-Al-Ti, Mg-Fe-Ti and Mg-Al-Fe compositions. We show that the ternary alloys in particular display remarkable sorption behavior: at 200 C the films are capable of absorbing 4-6 wt% hydrogen in seconds, and desorbing in minutes. Furthermore, this sorption behavior is stable over cycling for the Mg-Al-Ti and Mg-Fe-Ti alloys. Even after 100 absorption/desorption cycles, no degradation in capacity or kinetics is observed. For Mg-Al-Fe, the properties are clearly worse compared to the other ternary combinations. These differences are explained by considering the properties of all the different phases present during cycling in terms of their hydrogen affinity and catalytic activity. Based on these considerations, some general design principles for Mg-based hydrogen storage alloys are suggested. (author)

Hydrogen-rich saline attenuates anxiety-like behaviors in morphine-withdrawn mice.

Science.gov (United States)

Wen, Di; Zhao, Peng; Hui, Rongji; Wang, Jian; Shen, Qianchao; Gong, Miao; Guo, Hongyan; Cong, Bin; Ma, Chunling

2017-05-15

Hydrogen therapy is a new medical approach for a wide range of diseases. The effects of hydrogen on central nervous system-related diseases have recently become increasingly appreciated, but little is known about whether hydrogen affects the morphine withdrawal process. This study aims to investigate the potential effects of hydrogen-rich saline (HRS) administration on naloxone-precipitated withdrawal symptoms and morphine withdrawal-induced anxiety-like behaviors. Mice received gradually increasing doses (25-100 mg/kg, i.p.) of morphine over 3 days. In the naloxone-precipitated withdrawal procedure, the mice were treated with three HRS (20 μg/kg, i.p.) injections, and naloxone (1 mg/kg, i.p.) was given 30 min after HRS administration. Body weight, jumping behavior and wet-dog shakes were immediately assessed. In the spontaneous withdrawal procedure, the mice were treated with HRS (20 μg/kg, i.p.) every 8-h. Mice underwent naloxone-precipitated or spontaneous withdrawal were tested for anxiety-like behaviors in the elevated plus-maze (EPM) and light/dark box (L/D box) paradigm, respectively. In addition, the levels of plasma corticosterone were measured. We found that HRS administration significantly reduced body weight loss, jumping behavior and wet-dog shakes in mice underwent naloxone-precipitated withdrawal, and attenuated anxiety-like behaviors in the EPM and L/D box tests after naloxone-precipitated withdrawal or a 2-day spontaneous withdrawal period. Hypo-activity or motor impairment after HRS administration was not observed in the locomotion tests. Furthermore, HRS administration significantly decreased the levels of corticosterone in morphine-withdrawn mice. These are the first findings to indicate that hydrogen might ameliorate withdrawal symptoms and exert an anxiolytic-like effect in morphine-withdrawal mice. Copyright © 2017 Elsevier Ltd. All rights reserved.

Novel hydrogen decrepitation behaviors of (La, Ce)-Fe-B strips

Science.gov (United States)

Jin, Jiaying; Bai, Guohua; Zhang, Yujing; Peng, Baixing; Liu, Yongsheng; Ma, Tianyu; Yan, Mi

2018-05-01

La and Ce substitution for Nd in the 2:14:1-type sintered magnet is of commercial interest to reduce the material cost and to balance the utilization of rare earth (RE) sources. As hydrogen decrepitation (HD) is widely utilized to prepare the magnetic powders during magnets fabrication, incorporating La and Ce into the Nd-Fe-B permanent magnets, however, may exert complex influences on the decrepitation behavior. In the present work, through a comparative study of the HD behaviors between the (La, Ce)-Fe-B strips and the conventional Nd-Fe-B ones, we find that similar to the Nd-Fe-B system, increasing hydrogen pressures from 2.5 to 5.5 MPa do not break the 2:14:1 tetragonal structure of (La, Ce)-Fe-B strips. The enhanced hydrogen absorption behaviors are observed with increasing pressure, which are still inferior to that of the Nd-Fe-B strips. This should be ascribed to the higher oxygen affinity of La and Ce than that of Nd, leading to the decreased amount of active RE-rich phase and limited hydrogen diffusion channel. As a result, the hydrogen absorption of 2:14:1 matrix phase is significantly suppressed, dramatically weakening the exothermic effect. This finding suggests that La and Ce with stable 2:14:1 tetragonal structure upon HD process are promising alternatives for Nd, despite that more precise oxygen control is necessary for the microstructure modification and magnetic performance enhancement of (La, Ce)-Fe-B sintered magnets.

Coupling of copper-chloride hybrid thermochemical water splitting cycle with a desalination plant for hydrogen production from nuclear energy

International Nuclear Information System (INIS)

Orhan, Mehmet F.; Dincer, Ibrahim; Naterer, Greg F.; Rosen, Marc A.

2010-01-01

Energy and environmental concerns have motivated research on clean energy resources. Nuclear energy has the potential to provide a significant share of energy supply without contributing to environmental emissions and climate change. Nuclear energy has been used mainly for electric power generation, but hydrogen production via thermochemical water decomposition provides another pathway for the utilization of nuclear thermal energy. One option for nuclear-based hydrogen production via thermochemical water decomposition uses a copper-chloride (Cu-Cl) cycle. Another societal concern relates to supplies of fresh water. Thus, to avoid causing one problem while solving another, hydrogen could be produced from seawater rather than limited fresh water sources. In this study we analyze a coupling of the Cu-Cl cycle with a desalination plant for hydrogen production from nuclear energy and seawater. Desalination technologies are reviewed comprehensively to determine the most appropriate option for the Cu-Cl cycle and a thermodynamic analysis and several parametric studies of this coupled system are presented for various configurations. (author)

The annealing behavior of hydrogen implanted into Al-Si alloy

Energy Technology Data Exchange (ETDEWEB)

Ogura, Masahiko; Yamaji, Norisuke; Imai, Makoto; Itoh, Akio; Imanishi, Nobutsugu [Kyoto Univ. (Japan). Faculty of Engineering

1997-03-01

We have studied effects of not only defects but also an added elements on trap-sites of hydrogen in metals. For the purpose, we observed depth profiles and thermal behaviors of hydrogen implanted into Al-1.5at.%Si alloy samples in an implantation-temperature range of liquid nitrogen temperature (LNT) to 373K at different doses. The results were compared with those for pure aluminum samples. It was found that hydrogen is trapped as molecules in grain boundaries of Al/Si. (author)

Life Cycle Assessment of Hydrogen Production via Natural Gas Steam Reforming; TOPICAL

International Nuclear Information System (INIS)

Spath, P. L.; Mann, M. K.

2000-01-01

A life cycle assessment of hydrogen production via natural gas steam reforming was performed to examine the net emissions of greenhouse gases as well as other major environmental consequences. LCA is a systematic analytical method that helps identify and evaluate the environmental impacts of a specific process or competing processes

Life Cycle Assessment Of Hydrogen Production From Natural Gas Reforming Process

International Nuclear Information System (INIS)

Ozturk, M.

2010-01-01

Society has become concerned about the issues of natural resource depletion and environmental degradation. The environmental performance of products or processes has become a key issue, which is why ways to minimize the effects on the environment are investigated. The most effective tool for this purpose is called life cycle assessment (LCA). This concept considers the entire life cycle of product or process. The life cycle of a product begins with the extraction of raw materials from the earth to create the product and ends at the point when all materials are returned to the earth. LCA makes it possible to estimate the cumulative environmental impacts resulting from all stages in the product life cycle, often including impacts not considered in more traditional analyses. Therefore, LCA provides a comprehensive view of the environmental aspects of the product or process and a more accurate picture of the true environmental trade-offs in product selection. In the case of this study, life cycle assessments of hydrogen production via natural gas reforming process are investigated for environmental affect.

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight battery cells

Science.gov (United States)

Smithrick, John J.; Hall, Stephen W.

1990-01-01

A breakthrough in the low-earth-orbit (LEO) cycle life of individual pressure vessel (IPV) nickel hydrogen battery cells is reported. The cycle life of boiler plate cells containing 26 percent potassium hydroxide (KOH) electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH. The effect of KOH concentration on cycle life was studied. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min charge (2 x normal rate). The depth of discharge (DOD) was 80 percent. The cell temperature was maintained at 23 C. The next step is to validate these results using flight hardware and real time LEO test. NASA Lewis has a contract with the Naval Weapons Support Center (NWSC), Crane, Indiana to validate the boiler plate test results. Six 48 A-hr Hughes recirculation design IPV nickel-hydrogen flight battery cells are being evaluated. Three of the cells contain 26 percent KOH (test cells) and three contain 31 percent KOH (control cells). They are undergoing real time LEO cycle life testing. The cycle regime is a 90-min LEO orbit consisting of a 54-min charge followed by a 36-min discharge. The depth-of-discharge is 80 percent. The cell temperature is maintained at 10 C. The cells were cycled for over 8000 cycles in the continuing test. There were no failures for the cells containing 26 percent KOH. There were two failures, however, for the cells containing 31 percent KOH.

Acoustic emission monitoring of activation behavior of LaNi5 hydrogen storage alloy

Directory of Open Access Journals (Sweden)

Igor Maria De Rosa, Alessandro Dell'Era, Mauro Pasquali, Carlo Santulli and Fabrizio Sarasini

2011-01-01

Full Text Available The acoustic emission technique is proposed for assessing the irreversible phenomena occurring during hydrogen absorption/desorption cycling in LaNi5. In particular, we have studied, through a parametric analysis of in situ detected signals, the correlation between acoustic emission (AE parameters and the processes occurring during the activation of an intermetallic compound. Decreases in the number and amplitude of AE signals suggest that pulverization due to hydrogen loading involves progressively smaller volumes of material as the number of cycles increases. This conclusion is confirmed by electron microscopy observations and particle size distribution measurements.

Individual Pressure Vessel (PV) and Common Pressure Vessel (CPV) Nickel-Hydrogen Battery Performance Under LEO Cycling Conditions

Science.gov (United States)

Miller, Thomas B.; Lewis, Harlan L.

2004-01-01

LEO life cycle testing of Individual Pressure Vessel (PV) and Common Pressure Vessel (CPV) nickel-hydrogen cell packs have been sponsored by the NASA Aerospace Flight Battery Program. The cell packs have cycled under both 35% and 60% depth-of- discharge and temperature conditions of -5 C and +lO C. The packs have been on test since as early as 1992 and have generated a substantial database. This report will provide insight into performance trends as a function of the specific cell configuration and manufacturer for eight separate nickel-hydrogen battery cell packs.

Hydrogen storage behaviors of platinum-supported multi-walled carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Park, Soo-Jin; Lee, Seul-Yi [Department of Chemistry, Inha University, 253 Nam-gu, Incheon 402-751 (Korea, Republic of)

2010-12-15

In this work, the hydrogen storage behaviors of multi-walled carbon nanotubes (MWNTs) loaded by crystalline platinum (Pt) particles were studied. The microstructure of the Pt/MWNTs was characterized by X-ray diffraction and transmission electron microscopy. The pore structure and total pore volumes of the Pt/MWNTs were analyzed by N{sub 2}/77 K adsorption isotherms. The hydrogen storage capacity of the Pt/MWNTs was evaluated at 298 K and 100 bar. From the experimental results, it was found that Pt particles were homogeneously distributed on the MWNT surfaces. The amount of hydrogen storage capacity increased in proportion to the Pt content, with Pt-5/MWNTs exhibiting the largest hydrogen storage capacity. The superior amount of hydrogen storage was linked to an increase in the number of active sites and the optimum-controlled micropore volume for hydrogen adsorption due to the well-dispersed Pt particles. Therefore, it can be concluded that Pt particles play an important role in hydrogen storage characteristics due to the hydrogen spillover effect. (author)

Hydrogen production system based on high temperature gas cooled reactor energy using the sulfur-iodine (SI) thermochemical water splitting cycle

International Nuclear Information System (INIS)

Garcia, L.; Gonzalez, D.

2011-01-01

Hydrogen production from water using nuclear energy offers one of the most attractive zero-emission energy strategies and the only one that is practical on a substantial scale. Recently, strong interest is seen in hydrogen production using heat of a high-temperature gas-cooled reactor. The high-temperature characteristics of the modular helium reactor (MHR) make it a strong candidate for producing hydrogen using thermochemical or high-temperature electrolysis (HTE) processes. Eventually it could be also employ a high-temperature gas-cooled reactor (HTGR), which is particularly attractive because it has unique capability, among potential future generation nuclear power options, to produce high-temperature heat ideally suited for nuclear-heated hydrogen production. Using heat from nuclear reactors to drive a sulfur-iodine (SI) thermochemical hydrogen production process has been interest of many laboratories in the world. One of the promising approaches to produce large quantity of hydrogen in an efficient way using the nuclear energy is the sulfur-iodine (SI) thermochemical water splitting cycle. Among the thermochemical cycles, the sulfur iodine process remains a very promising solution in matter of efficiency and cost. This work provides a pre-conceptual design description of a SI-Based H2-Nuclear Reactor plant. Software based on chemical process simulation (CPS) was used to simulate the thermochemical water splitting cycle Sulfur-Iodine for hydrogen production. (Author)

Design and reliability assessment of control systems for a nuclear-based hydrogen production plant with copper-chlorine thermochemical cycle

Energy Technology Data Exchange (ETDEWEB)

Al-Dabbagh, Ahmad W. [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario, L1H 7K4 (Canada); Lu, Lixuan [Faculty of Energy Systems and Nuclear Science, Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario, L1H 7K4 (Canada)

2010-02-15

The thermochemical Copper-Chlorine (Cu-Cl) cycle is an emerging new method of nuclear-based hydrogen production. In the process, water is decomposed into hydrogen and oxygen through several physical and chemical processes. In this paper, a Distributed Control System (DCS) is designed for the thermochemical Cu-Cl cycle. The architecture and the communication networks of the DCS are discussed. Reliability of the DCS is assessed using fault trees. In the assessment, the impact of the malfunction of the actuators, sensors, controllers and communication networks on the overall system reliability is investigated. This provides key information for the selection of control system components, and determination of their inspection frequency and maintenance strategy. The hydrogen reactor unit, which is one of the major components in the thermochemical Cu-Cl cycle, is used to demonstrate the detailed design and analysis. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-03-15

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

Development of assessment technology for hydrogen burn and fission product behavior in containment

International Nuclear Information System (INIS)

Kim, S. B.; Kim, J. T.; Ha, K. S.; Hong, S. W.; Song, Y. M.; Park, J. H.; Cho, Y. R.; Kang, H. S.

2012-04-01

Analysis tools for hydrogen burn was established to resolve the hydrogen issues in containment. To validate CFX commercial CFD(computational fluid dynamics) code, the hydrogen combustion experiments such as FLAME and ENACEFF for reactor containment were analyzed. And OpenFOAM hydrogen combustion code was developed and validated. Experiments for the flame propagation characteristics in IRWST and the run-up-distance for DDT(Deflagration to detonation transition) were performed and analytical model was evaluated to evaluation of the performance of hydrogen mitigation system, that is, PAR(Passive auto-catalistic re-combiner) To improvement of the fission product modelling in containment, separate analysis module for Iodine behavior and its application tool of K-IODIP (Korea IODIne Package) were developed. PHEBUS FPT-3 analysis was performed to validate MELCOR code. And also the characteristics of fission product behaviors in Future Reactors(GEN-IV) were compared

Hydrogen permeation behavior through F82H at high temperature

Energy Technology Data Exchange (ETDEWEB)

Matsuda, S.; Katayama, K.; Shimozori, M.; Fukada, S. [Interdisciplinary Graduate School of Engineering Science, Kyushu University, Kyushu (Japan); Ushida, H. [Energy Science and Engineering, Faculty of Engineering, Kyushu University, Kyushu (Japan); Nishikawa, M. [Malaysia-Japan International Institute of Technology, UTM, Kuala Lumpur (Malaysia)

2015-03-15

F82H is a primary candidate of structural material and coolant pipe material in a blanket of a fusion reactor. Understanding tritium permeation behavior through F82H is important. In a normal operation of a fusion reactor, the temperature of F82H will be controlled below 550 C. degrees because it is considered that F82H can be used up to 30,000 hours at 550 C. degrees. However, it is necessary to assume the situation where F82H is heated over 550 C. degrees in a severe accident. In this study, hydrogen permeation behavior through F82H was investigated in the temperature range from 500 to 800 C. degrees. In some cases, water vapor was added in a sample gas to investigate an effect of water vapor on hydrogen permeation. The permeability of hydrogen in the temperature range from 500 to 700 C. degrees agreed well with the permeability reported by E. Serra et al. The degradation of the permeability by water vapor was not observed. After the hydrogen permeation reached in a steady state at 700 C. degrees, the F82H sample was heated to 800 C. degrees. The permeability of hydrogen through F82H sample which was once heated up to 800 C. degrees was lower than that of the original one. (authors)

Hydrogen isotope exchange in metal hydride columns

International Nuclear Information System (INIS)

Wiswall, R.; Reilly, J.; Bloch, F.; Wirsing, E.

1977-01-01

Several metal hydrides were shown to act as chromatographic media for hydrogen isotopes. The procedure was to equilibrate a column of hydride with flowing hydrogen, inject a small quantity of tritium tracer, and observe its elution behavior. Characteristic retention times were found. From these and the extent of widening of the tritium band, the heights equivalent to a theoretical plate could be calculated. Values of around 1 cm were obtained. The following are the metals whose hydrides were studied, together with the temperature ranges in which chromatographic behavior was observed: vanadium, 0 to 70 0 C; zirconium, 500 to 600 0 C; LaNi 5 , -78 to +30 0 C; Mg 2 Ni, 300 to 375 0 C; palladium, 0 to 70 0 C. A dual-temperature isotope separation process based on hydride chromatography was demonstrated. In this, a column was caused to cycle between two temperatures while being supplied with a constant stream of tritium-traced hydrogen. Each half-cycle was continued until ''breakthrough,'' i.e., until the tritium concentration in the effluent was the same as that in the feed. Up to that point, the effluent was enriched or depleted in tritium, by up to 20%

Catalytic effect of additional metallic phases on the hydrogen absorption behavior of a Zr-Based alloy

International Nuclear Information System (INIS)

Ruiz, F; Peretti, H; Castro, E; Real, S; Visitin, A; Triaca, W

2005-01-01

The electrochemical hydrogen absorption of electrodes containing Zr 0 .9Ti 0 .1(Ni 0 .5Mn 0 .25Cr 0 .20V 0 .05) 2 is studied in alkaline media by monitoring the activation and discharge capacity along charge-discharge cycling.The considered alloy is tested in both as melted and annealed condition in order to investigate the catalytic effect of small amounts of micro segregated secondary phases of the Zr-Ni system. Since these catalytic phases are only present in the as melted alloys, tests are also carried out using a composite material elaborated from powders of the annealed alloy with the addition of 18 wt.% of the suspected catalytic phases, melted separately.The hydrogen absorption-desorption behavior for the different cases is discussed and correlated with the metallurgical characterization of the materials.The catalytic effects are studied employing cyclic voltammetry and electrochemical impedance techniques. The results are analyzed in terms of a developed physicochemical model

Effects of hydrogen on fatigue of vanadium and niobium. Annual report

International Nuclear Information System (INIS)

Stoloff, N.S.; Chung, D.W.

1977-01-01

The fatigue behavior of unalloyed vanadium and niobium as well as their alloys with hydrogen is described. The response of vanadium-hydrogen alloys to cyclic loading is shown to depend markedly upon the presence or absence of notches, the hydrogen level, method of test, and frequency. In general, hydrides improve high cycle life of unnotched alloys, but are detrimental in the presence of a notch. Low test frequencies also lead to reduced fatigue lives. Stress-assisted hydride growth in previously hydrided alloys has been noted both in fatigue and in delayed failure experiments. Unalloyed vanadium and solid solution vanadium-hydrogen alloys do not undergo delayed failure. Preliminary tests on unalloyed niobium and several niobium-vanadium alloys reveal improvements in stress-controlled fatigue life and decreased low cycle life, in agreement with previous observations on vanadium-hydrogen alloys

Synfuels from fusion: using the tandem mirror reactor and a thermochemical cycle to produce hydrogen

International Nuclear Information System (INIS)

Werner, R.W.

1982-01-01

This study is concerned with the following area: (1) the tandem mirror reactor and its physics; (2) energy balance; (3) the lithium oxide canister blanket system; (4) high-temperature blanket; (5) energy transport system-reactor to process; (6) thermochemical hydrogen processes; (7) interfacing the GA cycle; (8) matching power and temperature demands; (9) preliminary cost estimates; (10) synfuels beyond hydrogen; and (11) thermodynamics of the H 2 SO 4 -H 2 O system

Life cycle cost analysis to examine the economical feasibility of hydrogen as an alternative fuel

International Nuclear Information System (INIS)

Lee, Ji-Yong; Yoo, Moosang; Cha, Kyounghoon; Hur, Tak; Lim, Tae Won

2009-01-01

This study uses a life cycle costing (LCC) methodology to identify when hydrogen can become economically feasible compared to the conventional fuels and which energy policy is the most effective at fostering the penetration of hydrogen in the competitive fuel market. The target hydrogen pathways in this study are H 2 via natural gas steam reforming (NG SR), H 2 via naphtha steam reforming (Naphtha SR), H 2 via liquefied petroleum gas steam reforming (LPG SR), and H 2 via water electrolysis (WE). In addition, the conventional fuels (gasoline, diesel) are also included for the comparison with the H 2 pathways. The life cycle costs of the target fuels are computed and several key factors are examined to identify the economical feasibilities of the target systems: fuel cell vehicle (FCV) price, social cost of greenhouse gases (GHGs) and regulated air emissions (CO, VOC, SO x , NO x , PM), fuel efficiency of FCV, capital costs of H 2 equipments at a H 2 fueling station. The life cycle costs of a H 2 pathway also depend on the production capacity. Although, at present, all H 2 pathways are more cost efficient than the conventional fuels in the fuel utilization stage, the H 2 pathways have lack competitiveness against the conventional fuels in the life cycle (well to wheel) costs due to the high price of FCV. From future scenario analyses in 2015, all H 2 pathways are expected to have lower life cycle costs than the conventional fuels as a transportation fuel. It is evident that the FCV price is the most important factor for encouraging the hydrogen economy and FCVs. Unless the FCV price is below US $62,320, it is necessary for the institution to subsidize the FCV price by any amount over US $62,320 in order to inject H 2 into the market of transportation fuel. The incentive or taxes on GHGs and regulated air emissions are also expected to effectively encourage the diffusion of H 2 and FCV, especially for the H 2 pathway of WE with wind power (WE[Wind]). The uncertainties

Behavior of implanted hydrogen in ferritic/martensitic steels under irradiation

Science.gov (United States)

Wan, F.; Takahashi, H.; Ohnuki, S.; Nagasaki, R.

1988-07-01

The aim of this study was to clarify the behavior of hydrogen under irradiation in ferritic/martensitic stainless steel Fe-10Cr-2Mo-1Ni. Hydrogen was implanted into the specimens by ion accelerator or chemical cathodic charging method, followed by electron irradiation in a HVEM at temperatures from room temperature to 773 K. Streaks in the electron diffraction patterns were observed only during electron irradiation at 623-723 K. From these results it is suggested that the occurrence of the streak pattern is due to the formation of radiation-induced complexes of Ni or Cr with hydrogen along directions.

Nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys

Energy Technology Data Exchange (ETDEWEB)

Tashlykova-Bushkevich, Iya I. [Belarusian State University of Informatics and Radioelectronics, Minsk (Belarus)

2015-12-31

The present work summarizes recent progress in the investigation of nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys foils produced at exceptionally high cooling rates. We focus here on the potential of modification of hydrogen desorption kinetics in respect to weak and strong trapping sites that could serve as hydrogen sinks in Al materials. It is shown that it is important to elucidate the surface microstructure of the Al alloy foils at the submicrometer scale because rapidly solidified microstructural features affect hydrogen trapping at nanostructured defects. We discuss the profound influence of solute atoms on hydrogen−lattice defect interactions in the alloys. with emphasis on role of vacancies in hydrogen evolution; both rapidly solidified pure Al and conventionally processed aluminum samples are considered.

Hydrogen retention behavior of beryllides as advanced neutron multipliers

Directory of Open Access Journals (Sweden)

Y. Fujii

2016-12-01

Full Text Available Beryllium intermetallic compounds (beryllides are the most promising candidate materials for use as advanced neutron multipliers in future fusion reactors because of their low swelling and high stability at high temperatures. Recently, beryllium–titanium beryllide pebbles such as Be12Ti have been successfully fabricated using a novel granulation process. In this study, the fundamental aspects of the behavior of hydrogen isotopes in Be12Ti pebbles were investigated via thermal desorption spectroscopy and transmission electron microscopy. In addition, atomistic calculations using first principles electronic-structure methods were applied to determine the solution energy of hydrogen in Be12Ti. The results showed simpler and weaker hydrogen-trapping efficiency for Be12Ti than for pure Be.

Decomposition analysis of cupric chloride hydrolysis in the Cu-Cl cycle of hydrogen production

International Nuclear Information System (INIS)

Daggupati, V.N.; Naterer, G.F.; Gabriel, K.S.; Gravelsins, R.; Wang, Z.

2009-01-01

This paper examines cupric chloride solid conversion during hydrolysis in a thermochemical copper-chlorine (Cu-Cl) cycle for hydrogen production. The hydrolysis reaction is a challenging step, in terms of the excess steam requirement and the decomposition of cupric chloride (CuCl 2 ) into cuprous chloride (CuCl) and chlorine (Cl 2 ). The hydrolysis and decomposition reactions are analyzed with respect to the chemical equilibrium constant. The effects of operating parameters are examined, including the temperature, pressure, excess steam and equilibrium conversion. A maximization of yield and selectivity are very important. Rate constants for the simultaneous reaction steps are determined using a uniform reaction model. A shrinking core model is used to determine the rate coefficients and predict the solid conversion time, with diffusional and reaction control. These new results are useful for scale-up of the engineering equipment in the thermochemical Cu-Cl cycle for hydrogen production. (author)

Synfuels from fusion: using the tandem mirror reactor and a thermochemical cycle to produce hydrogen

Energy Technology Data Exchange (ETDEWEB)

Werner, R.W. (ed.)

1982-11-01

This study is concerned with the following area: (1) the tandem mirror reactor and its physics; (2) energy balance; (3) the lithium oxide canister blanket system; (4) high-temperature blanket; (5) energy transport system-reactor to process; (6) thermochemical hydrogen processes; (7) interfacing the GA cycle; (8) matching power and temperature demands; (9) preliminary cost estimates; (10) synfuels beyond hydrogen; and (11) thermodynamics of the H/sub 2/SO/sub 4/-H/sub 2/O system. (MOW)

KOH concentration effect on the cycle life of nickel-hydrogen cells. 4: Results of failure analyse

Science.gov (United States)

Lim, H. S.; Verzwyvelt, S. A.

1989-01-01

Effects of KOH concentrations on failure modes and mechanisms of nickel-hydrogen cells were studied using long cycled boiler plate cells containing electrolytes of various KOH concentrations ranging 21 to 36 percent. Life of these cells were up to 40,000 cycles in an accelerated low earth orbit (LEO) cycle regime at 80 percent depth of discharge. An interim life test results were reported earlier in J. Power Sources, 22, 213-220, 1988. The results of final life test, end-of-life cell performance, and teardown analyses are discussed. These teardown analyses included visual observations, measurements of nickel electrode capacity in an electrolyte-flooded cell, dimensional changes of cell components, SEM studies on cell cross section, BET surface area and pore volume distribution in cycled nickel electrodes, and chemical analyses. Cycle life of a nickel-hydrogen cell was improved tremendously as KOH concentration was decreased from 36 to 31 percent and from 31 to 26 percent while effect of further concentration decrease was complicated as described in our earlier report. Failure mode of high concentration (31 to 36 percent) cells was gradual capacity decrease, while that of low concentration (21 to 26 percent) cells was mainly formation of a soft short. Long cycled (25,000 to 40,000 cycles) nickel electrodes were expanded more than 50 percent of the initial value, but no correlation was found between this expansion and measured capacity. All electrodes cycled in low concentration (21 to 26 percent) cells had higher capacity than those cycled in high concentration (31 to 36 percent) cells.

Effect of Gaseous Impurities on Long-Term Thermal Cycling and Aging Properties of Complex Hydrides for Hydrogen Storage

Energy Technology Data Exchange (ETDEWEB)

Chandra, Dhanesh [Primary Contact; Lamb, Joshua; Chien, Wen-Ming; Talekar, Anjali; and Pal, Narendra

2011-03-28

This program was dedicated to understanding the effect of impurities on Long-Term Thermal Cycling and aging properties of Complex Hydrides for Hydrogen Storage. At the start of the program we found reversibility between Li2NH+LiH LiH+LiNH2 (yielding ~5.8 wt.%H capacity). Then we tested the effect of impurity in H2 gas by pressure cycling at 255°C; first with industrial gas containing ppm levels of O2 and H2O as major impurities. Both these impurities had a significant impact on the reversibility and decreased the capacity by 2.65 wt.%H. Further increase in number of cycles from 500 to 1100 showed only a 0.2 wt%H more weight loss, showing some capacity is still maintained after a significant number of cycles. The loss of capacity is attributed to the formation of ~55 wt% LiH and ~30% Li2O, as major contaminant phases, along with the hydride Li2NH phase; suggesting loss of nitrogen during cycling. The effect of 100 ppm H2O in H2 also showed a decrease of ~2.5 wt.%H (after 560 cycles), and 100ppm O2 in H2; a loss of ~4.1 wt.%. Methane impurity (100 ppm, 100cycles), showed a very small capacity loss of 0.9 wt.%H under similar conditions. However, when Li3N was pressure cycled with 100ppmN2-H2 there were beneficial effects were observed (255oC); the reversible capacity increased to 8.4wt.%H after 853 cycles. Furthermore, with 20 mol.%N2-H2 capacity increased to ~10 wt.%H after 516 cycles. We attribute this enhancement to the reaction of nitrogen with liquid lithium during cycling as the Gibbs free energy of formation of Li3N (Go = -98.7 kJ/mol) is more negative than that of LiH (Go = -50.3 kJ/mol). We propose that the mitigation of hydrogen capacity losses is due to the destabilization of the LiH phase that tends to accumulate during cycling. Also more Li2NH phase was found in the cycled product. Mixed Alanates (3LiNH2:Li3AlH6) showed that 7 wt% hydrogen desorbed under dynamic vacuum. Equilibrium experiments (maximum 12 bar H2) showed up to 4wt% hydrogen reversibly

Hydrogen production with fully integrated fuel cycle gas and vapour core reactors

International Nuclear Information System (INIS)

Anghaie, S.; Smith, B.

2004-01-01

This paper presents results of a conceptual design study involving gas and vapour core reactors (G/VCR) with a combined scheme to generate hydrogen and power. The hydrogen production schemes include high temperature electrolysis as well as two dominant thermochemical hydrogen production processes. Thermochemical hydrogen production processes considered in this study included the calcium-bromine process and the sulphur-iodine processes. G/VCR systems are externally reflected and moderated nuclear energy systems fuelled by stable uranium compounds in gaseous or vapour phase that are usually operated at temperatures above 1500 K. A gas core reactor with a condensable fuel such as uranium tetrafluoride (UF 4 ) or a mixture of UF 4 and other metallic fluorides (BeF 2 , LiF, KF, etc.) is commonly known as a vapour core reactor (VCR). The single most relevant and unique feature of gas/vapour core reactors is that the functions of fuel and coolant are combined into one. The reactor outlet temperature is not constrained by solid fuel-cladding temperature limits. The maximum fuel/working fluid temperature in G/VCR is only constrained by the reactor vessel material limits, which is far less restrictive than the fuel clad. Therefore, G/VCRs can potentially provide the highest reactor and cycle temperature among all existing or proposed fission reactor designs. Gas and vapour fuel reactors feature very low fuel inventory and fully integrated fuel cycle that provide for exceptional sustainability and safety characteristics. With respect to fuel utilisation, there is no fuel burn-up limit for gas core reactors due to continuous recycling of the fuel. Owing to the flexibility in nuclear design characteristics of cavity reactors, a wide range of conversion ratio from completely burner to breeder is achievable. The continuous recycling of fuel in G/VCR systems allow for complete burning of actinides without removing and reprocessing of the fuel. The only waste products at the back

Microstructure and kinetics evolution in MgH{sub 2}–TiO{sub 2} pellets after hydrogen cycling

Energy Technology Data Exchange (ETDEWEB)

Mirabile Gattia, D., E-mail: daniele.mirabile@enea.it; Di Girolamo, G.; Montone, A.

2014-12-05

Highlights: • MgH{sub 2} was ball milled with TiO{sub 2} anatase phase and expanded graphite to prepare pellets. • Different pellets have been prepared at different compression load. • Pellets were repeatedly cycled under hydrogen pressure to simulate tank exercise and verify their stability. • The compression load highly affects the stability of the pellets to cycling. • Microstructural evolution of the particles due to cycling have been observed. - Abstract: The interest in Mg-based hydrides for solid state hydrogen storage is associated to their capability to reversibly absorb and desorb large amounts of hydrogen. In this work MgH{sub 2} powder with 5 wt.% TiO{sub 2} was ball milled for 10 h. The as-milled nanostructured powder was enriched with 5 wt.% of Expanded Natural Graphite (ENG) and then compacted in cylindrical pellets by cold pressing using different loads. Both the powder and the pellets were subjected to kinetic and thermodynamic tests using a Sievert’s type gas reaction controller, in order to study the microstructural and kinetic changes which took place during repeated H{sub 2} absorption and desorption cycles. The pellets exhibited good kinetic performance and durability, even if the pressure of compaction revealed to be an important parameter for their mechanical stability. Scanning Electron Microscopy observations of as-prepared and cycled pellets were carried out to investigate the evolution of their microstructure. In turn the phase composition before and after cycling was analyzed by X-ray diffraction.

Combined Reverse-Brayton Joule Thompson Hydrogen Liquefaction Cycle

Energy Technology Data Exchange (ETDEWEB)

Shimko, Martin A. [Gas Equipment Engineering Corporation, Milford, CT (United States); Dunn, Paul M. [Gas Equipment Engineering Corporation, Milford, CT (United States)

2011-12-31

The following is a compilation of Annual Progress Reports submitted to the DOE’s Fuel Cell Technologies Office by Gas Equipment Engineering Corp. for contract DE-FG36-05GO15021. The reports cover the project activities from August 2005 through June 2010. The purpose of this project is to produce a pilot-scale liquefaction plant that demonstrates GEECO’s ability to meet or exceed the efficiency targets set by the DOE. This plant will be used as a model to commercialize this technology for use in the distribution infrastructure of hydrogen fuel. It could also be applied to markets distributing hydrogen for industrial gas applications. Extensive modeling of plant performance will be used in the early part of the project to identify the liquefaction cycle architecture that optimizes the twin goals of increased efficiency and reduced cost. The major challenge of the project is to optimize/balance the performance (efficiency) of the plant against the cost of the plant so that the fully amortized cost of liquefying hydrogen meets the aggressive goals set by DOE. This project will design and build a small-scale pilot plant (several hundred kg/day) that will be both a hardware demonstration and a model for scaling to larger plant sizes (>50,000 kg/day). Though an effort will be made to use commercial or near-commercial components, key components that will need development for either a pilot- or full-scale plant will be identified. Prior to starting pilot plant fabrication, these components will be demonstrated at the appropriate scale to demonstrate sufficient performance for use in the pilot plant and the potential to achieve the performance used in modeling the full-scale plant.

Life-cycle implications of hydrogen fuel cell electric vehicle technology for medium- and heavy-duty trucks

Science.gov (United States)

Lee, Dong-Yeon; Elgowainy, Amgad; Kotz, Andrew; Vijayagopal, Ram; Marcinkoski, Jason

2018-07-01

This study provides a comprehensive and up-to-date life-cycle comparison of hydrogen fuel cell electric trucks (FCETs) and their conventional diesel counterparts in terms of energy use and air emissions, based on the ensemble of well-established methods, high-fidelity vehicle dynamic simulations, and real-world vehicle test data. For the centralized steam methane reforming (SMR) pathway, hydrogen FCETs reduce life-cycle or well-to-wheel (WTW) petroleum energy use by more than 98% compared to their diesel counterparts. The reduction in WTW air emissions for gaseous hydrogen (G.H2) FCETs ranges from 20 to 45% for greenhouse gases, 37-65% for VOC, 49-77% for CO, 62-83% for NOx, 19-43% for PM10, and 27-44% for PM2.5, depending on vehicle weight classes and truck types. With the current U.S. average electricity generation mix, FCETs tend to create more WTW SOx emissions than their diesel counterparts, mainly because of the upstream emissions related to electricity use for hydrogen compression/liquefaction. Compared to G.H2, liquid hydrogen (L.H2) FCETs generally provide smaller WTW emissions reductions. For both G.H2 and L.H2 pathways for FCETs, because of electricity consumption for compression and liquefaction, spatio-temporal variations of electricity generation can affect the WTW results. FCETs retain the WTW emission reduction benefits, even when considering aggressive diesel engine efficiency improvement.

Effect of hydrogen on the corrosion behavior of the Mg–xZn alloys

Directory of Open Access Journals (Sweden)

Yingwei Song

2014-09-01

Full Text Available Hydrogen evolution reaction is inevitable during the corrosion of Mg alloys. The effect of hydrogen on the corrosion behavior of the Mg–2Zn and Mg–5Zn alloys is investigated by charging hydrogen treatment. The surface morphologies of the samples after charging hydrogen were observed using a scanning electron microscopy (SEM and the corrosion resistance was evaluated by polarization curves. It is found that there are oxide films formed on the surface of the charged hydrogen samples. The low hydrogen evolution rate is helpful to improve the corrosion resistance of Mg alloys, while the high hydrogen evolution rate can increases the defects in the films and further deteriorates their protection ability. Also, the charging hydrogen effect is greatly associated with the microstructure of Mg substrate.

Hydrogen behavior in a large-dry pressurized water reactor containment building during a severe accident

International Nuclear Information System (INIS)

Hsu Wensheng; Chen Hungpei; Hung Zhenyu; Lin Huichen

2014-01-01

Following severe accidents in nuclear power plants, large quantities of hydrogen may be generated after core degradation. If the hydrogen is transported from the reactor vessel into the containment building, an explosion might occur, which might threaten the integrity of the building; this can ultimately cause the release of radioactive materials. During the Fukushima Daiichi nuclear accident in 2011, the primary containment structures remained intact but contaminated fragments broke off the secondary containment structures, which disrupted mitigation activities and triggered subsequent explosions. Therefore, the ability to predict the behavior of hydrogen after severe accidents may facilitate the development of effective nuclear reactor accident management procedures. The present study investigated the behavior of hydrogen in a large-dry pressurized water reactor (PWR). The amount of hydrogen produced was calculated using the Modular Accident Analysis Program. The hydrogen transport behavior and the effect of the explosion on the PWR containment building were simulated using the Flame Acceleration Simulator. The simulation results showed that the average hydrogen volume fraction is approximately 7% in the containment building and that the average temperature is 330 K. The maximum predicted pressure load after ignition is 2.55 bar, which does not endanger the structural integrity of the containment building. The results of this investigation indicate that the hydrogen mitigation system should be arranged on both the upper and lower parts of the containment building to reduce the impact of an explosion. (author)

Cognitive-Behavioral Therapy for Rapid Cycling Bipolar Disorder

Science.gov (United States)

Reilly-Harrington, Noreen A.; Knauz, Robert O.

2005-01-01

This article describes the application of cognitive-behavioral therapy (CBT) to the treatment of rapid cycling bipolar disorder. Between 10% and 24% of bipolar patients experience a rapid cycling course, with 4 or more mood episodes occurring per year. Characterized by nonresponse to standard mood-stabilizing medications, rapid cyclers are…

Effect of p-type multi-walled carbon nanotubes for improving hydrogen storage behaviors

International Nuclear Information System (INIS)

Lee, Seul-Yi; Yop Rhee, Kyong; Nahm, Seung-Hoon; Park, Soo-Jin

2014-01-01

In this study, the hydrogen storage behaviors of p-type multi-walled carbon nanotubes (MWNTs) were investigated through the surface modification of MWNTs by immersing them in sulfuric acid (H 2 SO 4 ) and hydrogen peroxide (H 2 O 2 ) at various ratios. The presence of acceptor-functional groups on the p-type MWNT surfaces was confirmed by X-ray photoelectron spectroscopy. Measurement of the zeta-potential determined the surface charge transfer and dispersion of the p-type MWMTs, and the hydrogen storage capacity was evaluated at 77 K and 1 bar. From the results obtained, it was found that acceptor-functional groups were introduced onto the MWNT surfaces, and the dispersion of MWNTs could be improved depending on the acid-mixed treatment conditions. The hydrogen storage was increased by acid-mixed treatments of up to 0.36 wt% in the p-type MWNTs, compared with 0.18 wt% in the As-received MWNTs. Consequently, the hydrogen storage capacities were greatly influenced by the acceptor-functional groups of p-type MWNT surfaces, resulting in increased electron acceptor–donor interaction at the interfaces. - Graphical abstract: Hydrogen storage behaviors of the p-type MWNTs with the acid-mixed treatments are described. Display Omitted Display Omitted

Effect of hydrogen on transformation characteristics and deformation behavior in a Ti-Ni shape memory alloy

International Nuclear Information System (INIS)

Hoshiya, Taiji; Ando, Hiroei; Den, Shoji; Katsuta, Hiroshi.

1992-01-01

Transformation characteristics and deformation behavior of hydrogenated Ti-50.5 at% Ni alloys, which were occluded in a low pressure range of hydrogen between 1.1 and 78.5 kPa, have been studied by electrical resistivity measurement, tensile test, X-ray diffraction analysis and microstructural observation. M S temperature of the Ti-Ni alloys decreased with an increase in hydrogen content. This corresponds to the stabilization of the parent phase during cooling, which was confirmed by X-ray diffraction: The suppression effect of hydrogen takes place on the martensitic transformation. Critical stress for slip deformation of hydrogenated Ti-Ni alloys changed with hydrogen content and thus hydrogen had a major influence on deformation behavior of those alloys. With hydrogen contents above 0.032 mol%, hardening was distinguished from softening which was pronounced in the contents from 0 to 0.032 mol% H. Hydrides were formed in hydrogen contents over 1.9 mol%. The hydride formation results in the reorientation in variants of the R phase and increase in the lattice strains of the parent phase. (author)

Attentiveness cycles: synchronized behavior and aggregate fluctuations

Directory of Open Access Journals (Sweden)

Orlando Gomes

2012-09-01

Full Text Available A sticky-information macroeconomic model is developed in order to analyze the behavior of the time trajectories of the inflation rate and of the output gap, when disturbed by eventual monetary policy shocks. In opposition to what is typical in the literature on this subject, different paces on information updating explicitly lead to a setting with interaction among heterogeneous agents. Specifically, we consider firms with different information updating frequencies whose behavior implies the emergence of attentiveness cycles of possibly large lengths; within these cycles we deduct a differently shaped Phillips curve for each time period. Systematic changes on the form of the aggregate supply relation will be the engine that triggers a sluggish response to shocks and the eventual persistence of business fluctuations.

Closed-Cycle Hydrogen-Oxygen Regenerative Fuel Cell at the NASA Glenn Research Center-An Update

Science.gov (United States)

Bents, David J.; Chang, Bei-Jiann; Johnson, Donald W.; Garcia, Christopher P.

2008-01-01

The closed cycle hydrogen-oxygen proton exchange membrane (PEM) regenerative fuel cell (RFC) at the NASA Glenn Research Center has demonstrated multiple back-to-back contiguous cycles at rated power and round-trip efficiencies up to 52 percent. It is the first fully closed cycle RFC ever demonstrated. (The entire system is sealed; nothing enters or escapes the system other than electrical power and heat.) During fiscal year fiscal year (FY) FY06 to FY07, the system s numerous modifications and internal improvements focused on reducing parasitic power, heat loss, and noise signature; increasing its functionality as an unattended automated energy storage device; and in-service reliability.

Oxide characterization and hydrogen behaviors of Zr-based alloys

International Nuclear Information System (INIS)

Kim, Y. S.; Kim, D. J.; Kwon, S. H.; Lee, H. S.; Oh, S. J.; Yim, B. J.; Son, S. B.; Yun, S. P.

2006-03-01

The work scope and contents of the research are as follows : basic properties of zirconium alloys, hydrogen pick-up mechanism of zirconium alloy, effects of hydride on the corrosion behaviors of zirconium alloys, estimation on stress of oxide layer in the zirconium alloy, microstructure and characteristic of oxide in pre-hydrided zirconium alloys

Low-cycle fatigue behaviors of pre-hardening Hadfield steel

Energy Technology Data Exchange (ETDEWEB)

Chen, Chen [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Lv, Bo [College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China); Wang, Fei [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Zhang, Fucheng, E-mail: zfc@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004 (China)

2017-05-17

Low-cycle fatigue behaviors of the pre-hardening (PH) and the water-quenching (WQ) Hadfield steel were studied using optical microscopy, transmission electron microscopy, and electron backscatter diffraction technique. The effect of the PH treatment on low-cycle fatigue behavior of the Hadfield steel was analyzed through comparing the cyclic hardening/softening behaviors and the changing regulations of stress amplitude, internal stress, and effective stress at different total strain amplitudes. Results showed obvious differences in fatigue behaviors between the PH (with a cold rolling deformation degree of 40%) and the WQ Hadfield steels. Transient hardening followed by cyclic stability behavior occurred in the PH Hadfield steel under cyclic loading, whereas cyclic softening behavior was barely observed. The fatigue life of the PH Hadfield steel was higher than that of the WQ Hadfield steel at relatively low strain amplitudes, while a contrary result was obtained at relatively high strain amplitudes. At low strain amplitudes, the deformation twins induced in the PH Hadfield steel could enhance the multiplication and slip process of dislocations, which actually improved the deformation uniformity. The long-range motion of dislocations was intensified at high strain amplitudes. However, the dislocation motion was also blocked by twin boundaries. As a result, the interactions between dislocations and deformation twins enhanced, finally causing severe dislocation accumulation. These two effects of deformation twins on dislocation motion eventually resulted in different low-cycle fatigue behaviors of the PH Hadfield steel.

Recent progress of hydrogen isotope behavior studies for neutron or heavy ion damaged W

International Nuclear Information System (INIS)

Oya, Yasuhisa; Hatano, Yuji; Shimada, Masashi; Buchenauer, Dean; Kolasinski, Robert; Merrill, Brad; Kondo, Sosuke; Hinoki, Tatsuya; Alimov, Vladimir Kh.

2016-01-01

Highlights: • This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. • Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. • The distribution of defects throughout the sample also changes the shape of TDS spectrum. • Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed. - Abstract: This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. In particular, the desorption temperature shifts higher as the defect concentration increases. In addition, the distribution of defects throughout the sample also changes the shape of TDS spectrum. Even if low energy traps were distributed in the bulk region, the D diffusion toward the surface requires additional time for trapping/detrapping during surface-to-bulk transport, contributing to a shift of desorption peaks toward higher temperatures. It can be said that both of distribution of damage (e.g. hydrogen isotope trapping sites) and their stabilities would have a large impact on desorption. In addition, transmutation effects should be also considered for an actual fusion environment. Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed.

Recent progress of hydrogen isotope behavior studies for neutron or heavy ion damaged W

Energy Technology Data Exchange (ETDEWEB)

Oya, Yasuhisa, E-mail: syoya@ipc.shizuoka.ac.jp [Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529 (Japan); Hatano, Yuji [University of Toyama, 3190 Gofuku, Toyama 939-8555 (Japan); Shimada, Masashi [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Buchenauer, Dean; Kolasinski, Robert [Sandia National Laboratories, Livermore, CA 94551 (United States); Merrill, Brad [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Kondo, Sosuke; Hinoki, Tatsuya [Kyoto University, Gokasho, Uji 611-0011 (Japan); Alimov, Vladimir Kh. [University of Toyama, 3190 Gofuku, Toyama 939-8555 (Japan)

2016-12-15

Highlights: • This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. • Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. • The distribution of defects throughout the sample also changes the shape of TDS spectrum. • Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed. - Abstract: This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. In particular, the desorption temperature shifts higher as the defect concentration increases. In addition, the distribution of defects throughout the sample also changes the shape of TDS spectrum. Even if low energy traps were distributed in the bulk region, the D diffusion toward the surface requires additional time for trapping/detrapping during surface-to-bulk transport, contributing to a shift of desorption peaks toward higher temperatures. It can be said that both of distribution of damage (e.g. hydrogen isotope trapping sites) and their stabilities would have a large impact on desorption. In addition, transmutation effects should be also considered for an actual fusion environment. Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed.

Studies on closed-cycle processes for hydrogen production, 3

International Nuclear Information System (INIS)

Sato, Shoichi; Ikezoe, Yasumasa; Shimizu, Saburo; Nakajima, Hayato; Kobayashi, Toshiaki

1978-10-01

Studies made in fiscal 1977 on the thermochemical and radiation chemical processes for hydrogen production are reported. In the thermochemical process, cerium (III) carbonate was used as an intermediate, and a workable process was found, which consisted of eight reaction steps. In other feasible processes, carbon dioxide was made to react with iron (II) chloride or iodide at high temperature to form carbon monoxide, and three or four reaction steps ensued. Also, an improved process of the sulfur cycle was studied. In this process, nickel salts were separated by solvent extraction. Estimated thermal efficiency (HHV) of the process was 30 - 40%, assuming 70 - 80% heat recovery. In the radiation chemical process, carbon dioxide was added with propane or nitrogen dioxide and radiolyzed: reaction mechanisms are discussed. (author)

Enhancement of Hydrogen Storage Behavior of Complex Hydrides via Bimetallic Nanocatalysts Doping

Directory of Open Access Journals (Sweden)

Prakash C. Sharma

2012-10-01

Full Text Available Pristine complex quaternary hydride (LiBH4/2LiNH2 and its destabilized counterpart (LiBH4/2LiNH2/nanoMgH2 have recently shown promising reversible hydrogen storage capacity under moderate operating conditions. The destabilization of complex hydride via nanocrystalline MgH2 apparently lowers the thermodynamic heat values and thus enhances the reversible hydrogen storage behavior at moderate temperatures. However, the kinetics of these materials is rather low and needs to be improved for on-board vehicular applications. Nanocatalyst additives such as nano Ni, nano Fe, nano Co, nano Mn and nano Cu at low concentrations on the complex hydride host structures have demonstrated a reduction in the decomposition temperature and overall increase in the hydrogen desorption reaction rates. Bi-metallic nanocatalysts such as the combination of nano Fe and nano Ni have shown further pronounced kinetics enhancement in comparison to their individual counterparts. Additionally, the vital advantage of using bi-metallic nanocatalysts is to enable the synergistic effects and characteristics of the two transitional nanometal species on the host hydride matrix for the optimized hydrogen storage behavior.

The pipeline fracture behavior and pressure assessment under HIC (Hydrogen induced cracking) environment

Energy Technology Data Exchange (ETDEWEB)

Shaohua, Dong [China National Petroleum Corporation (CNPC), Beijing (China); Lianwei, Wang [University of Science and Technology Beijing (USTB), Beijing (China)

2009-07-01

As Hydrogen's transmit and diffuse, after gestating for a while, the density of hydrogen around crack tip of pipeline will get to the critical density, and the pipeline material will descend, make critical stress factor, the reason of pipeline Hydrogen Induced Cracking is Hydrogen's transmit and diffuse. The stress factor of Hydrogen Induced Cracking under surroundings-condition of stress is the key that estimate material's rupture behavior. The paper study the relationship among hydrogen concentrate, crack tip stress, stain field, hydrogen diffusion and inner pressure for crack tip process zone, then determined the length of HIC (hydrogen induced cracking) process zone. Based on the theory of propagation which reason micro-crack making core, dislocation model is produced for fracture criteria of HIC, the influence between material and environments under the HIC is analyzed, step by step pipeline maximum load pressure and threshold of J-integrity ( J{sub ISCC} ) is calculated, which is very significant for pipeline safety operation. (author)

Degradation of materials under conditions of thermochemical cycles for hydrogen production

International Nuclear Information System (INIS)

Klimas, S.J.; Searle, H.; Stolberg, L.

2010-01-01

A capsule method has been developed and employed to measure the degradation rates of selected materials under some of the most challenging conditions relevant to the sulphur-iodine (SI) and the copper-chlorine (Cu-Cl) thermochemical cycles for hydrogen production. The materials tested so far include metals and engineering alloys, structural and functional polymers, elastomers, carbon-based materials, ceramics and glasses, and composites. A number of characterization methods have been used to detect and quantify the degradation of the diverse materials and, when feasible, establish the mode of attack. The paper details the results of this ongoing experimental investigation. The investigation currently focuses on the copper-chlorine hybrid cycle. The environment representative of the conditions in the electrolyser subsystem was approximated with an aqueous solution of hydrochloric acid (13.6 mol/kg), copper(II) chloride (1.36 mol/kg) and copper(I) chloride (1.36 mol/kg) at 160°C and 2.5 MPa (absolute). The current (tentative) recommendations for the selection of the materials required for the construction of the electrolyser subsystem of the copper-chlorine hybrid cycle, and the associated rationale, are presented and discussed. (author)

Social-cognitive correlates of risky adolescent cycling behavior

Directory of Open Access Journals (Sweden)

Ruiter Robert AC

2010-07-01

Full Text Available Abstract Background Bicycle use entails high safety and health risks especially for adolescents. Most safety education programs aimed at adolescents focus on accident statistics and risk perceptions. This paper proposes the investigation of the social-cognitive correlates of risky cycling behaviors of adolescents prior to developing safety education programs. Method Secondary school students aged 13 to 18 years (n = 1446 filled out questionnaires regarding bicycle behavior, risky intentions, accident experience, and social-cognitive determinants as suggested by the theory of planned behavior. Results Regression analysis revealed that the proximal variables (i.e., self-efficacy, attitudes towards drunk driving, personal norm regarding safekeeping of self and others, and compared risk were able to predict 17% of the variance of risky behavior and 23% of the variance of risky intentions. The full model explained respectively 29% and 37% of the variance in risky behavior and risky intentions. Adolescents with positive attitudes towards risky behavior and low sense of responsibility report risky behavior, even when having been (close to an accident. Conclusions Adolescents realize whether they are risk takers or not. This implies that the focus of education programs should not be on risk perceptions, but on decreasing positive attitudes towards alcohol in traffic and increasing sense of responsibility instead. Cognitions regarding near accidents should be studied, the role of safe cycling self-efficacy is unclear.

Role of hydrogen on the incipient crack tip deformation behavior in α-Fe: An atomistic perspective

Science.gov (United States)

Adlakha, I.; Solanki, K. N.

2018-01-01

A crack tip in α-Fe presents a preferential trap site for hydrogen, and sufficient concentration of hydrogen can change the incipient crack tip deformation response, causing a transition from a ductile to a brittle failure mechanism for inherently ductile alloys. In this work, the effect of hydrogen segregation around the crack tip on deformation in α-Fe was examined using atomistic simulations and the continuum based Rice-Thompson criterion for various modes of fracture (I, II, and III). The presence of a hydrogen rich region ahead of the crack tip was found to cause a decrease in the critical stress intensity factor required for incipient deformation for various crack orientations and modes of fracture examined here. Furthermore, the triaxial stress state ahead of the crack tip was found to play a crucial role in determining the effect of hydrogen on the deformation behavior. Overall, the segregation of hydrogen atoms around the crack tip enhanced both dislocation emission and cleavage behavior suggesting that hydrogen has a dual role during the deformation in α-Fe.

Thermochemical cycles based on metal oxides for solar hydrogen production; Ciclos termoquimicos basados en oxidos metalicos para produccion de hidrogeno solar

Energy Technology Data Exchange (ETDEWEB)

Fernandez Saavedra, R.; Quejido Cabezas, J.

2012-11-01

The growing demand for energy requires the development and optimization of alternative energy sources. One of the options currently being investigated is solar hydrogen production with thermochemical cycles. This process involves the use of concentrated solar radiation as an energy source to dissociate water through a series of endothermic and exothermic chemical reactions, for the purpose of obtaining hydrogen on a sustainable basis. Of all the thermochemical cycles that have been evaluated, the most suitable ones for implementation with solar energy are those based on metal oxides. (Author) 20 refs.

The behavior of hydrogen in metals

International Nuclear Information System (INIS)

Hirabayashi, Makoto

1975-01-01

Explanation is made on the equilibrium diagrams of metal-hydrogen systems and the state of hydrogen in metals. Some metals perform exothermic reaction with hydrogen, and the others endothermic reaction. The former form stable hydrides and solid solutions over a wide range of composition. Hydrogen atoms in fcc and bcc metals are present at the interstitial positions of tetrahedron lattice and octahedron lattice. For example, hydrogen atoms in palladium are present at the intersititial positions of octahedron. When the ratio of the composition of hydrogen and palladium is 1:1, the structure becomes NaCl type. Hydrogen atoms in niobium and vanadium and present interstitially in tetrahedron lattice. Metal hydrides with high hydrogen concentration are becoming important recently as the containers of hydrogen. Hydrogen atoms diffuse in metals quite easily. The activation energy of the diffusion of hydrogen atoms in Nb and V is about 2-3 kcal/g.atom. The diffusion coefficient is about 10 -5 cm 2 /sec in alpha phase at room temperature. The number of jumps of a hydrogen atom between neighboring lattice sites is 10 11 --10 12 times per second. This datum is almost the same as that of liquid metals. Discussion is also made on the electronic state of hydrogen in metals. (Fukutomi, T.)

Analysis of transient permeation behavior of hydrogen isotope caused by abrupt temperature change of first wall and blanket wall material

International Nuclear Information System (INIS)

Yamawaki, Michio; Tanaka, Satoru; Kiyoshi, Tsukasa

1989-01-01

To obtain further information on the transient permeation behavior of hydrogen isotopes as caused by an abrupt temperature change, numerical calculations were carried out for two typical metals, nickel and vanadium. Deuterium permeation through nickel is analyzed as a typical case of bulk-diffusion-limited permeation. Its transient behavior changed dramatically according to the specimen thickness. The transient behavior, in general, is separated into two parts, initial and latter period behaviors. Conditions which cause such a separation were evaluated. Evaluation of the hydrogen diffusivity and solubility by an analysis of transient curves of hydrogen permeation was carried out. The transient behavior of simultaneous gas- and ion-driven hydrogen permeation through vanadium was also analyzed. Overshooting of the hydrogen permeation rate appears with an abrupt temperature increase. Increasing the impinging ion flux causes the overshooting peak to become sharper, and also reduces the change of the steady-state permeation rate to be attained after the temperature change compared with the initial value. (orig.)

Fatigue Crack Growth Behavior of Austempered AISI 4140 Steel with Dissolved Hydrogen

Directory of Open Access Journals (Sweden)

Varun Ramasagara Nagarajan

2017-11-01

Full Text Available The focus of this investigation was to examine the influence of dissolved hydrogen on the fatigue crack growth behavior of an austempered low-alloy AISI 4140 steel. The investigation also examined the influence of dissolved hydrogen on the fatigue threshold in this material. The material was tested in two conditions, as-received (cold rolled and annealed and austempered (austenitized at 882 °C for 1 h and austempered at 332 °C for 1 h. The microstructure of the annealed specimens consisted of a mix of ferrite and fine pearlite; the microstructure of the austempered specimens was lower bainite. Tensile and Compact Tension specimens were prepared. To examine the influence of dissolved hydrogen, two subsets of the CT specimens were charged with hydrogen for three different time periods between 150 and 250 h. All of the CT samples were then subjected to fatigue crack growth tests in the threshold and linear regions at room temperature. The test results indicate that austempering resulted in significant improvement in the yield and tensile strength as well as the fracture toughness of the material. The test results also show that, in the absence of dissolved hydrogen, the crack growth rate in the threshold and linear regions was lower in austempered samples compared to the as-received (annealed samples. The fatigue threshold was also slightly greater in the austempered samples. In presence of dissolved hydrogen, the crack growth rate was dependent upon the ∆K value. In the low ∆K region (<30 MPa√m, the presence of dissolved hydrogen caused the crack growth rate to be higher in the austempered samples as compared to annealed samples. Above this value, the crack growth rate was increasingly greater in the annealed specimens when compared to the austempered specimens in presence of dissolved hydrogen. It is concluded that austempering of 4140 steel appears to provide a processing route by which the strength, hardness, and fracture toughness of

A Study on the VHCF Fatigue Behaviors of Hydrogen Attacked Inconel 718 Alloy

Energy Technology Data Exchange (ETDEWEB)

Suh, Chang-Min [Kyungpook National Univ., DMI Senior Fellow, Daegu (Korea, Republic of); Nahm, Seung-Hoon [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Kim, Jun-Hyong; Pyun, Young-Sik [Sun Moon Univ., Chunan (Korea, Republic of)

2016-07-15

This study is to investigate the influence of hydrogen attack and UNSM on fatigue behaviors of the Inconel 718 alloy. The decrease of the fatigue life between the untreated and the hydrogen attacked material is 10-20%. The fatigue lives of hydrogen attacked specimen decreased without a fatigue limit, similar to those of nonferrous materials. Due to hydrogen embrittlement, about 80% of the surface cracks were smaller than the average grain size of 13 μm. Many small surface cracks caused by the embrittling effect of hydrogen attack were initiated at the grain boundaries and surface scratches. Cracks were irregularly distributed, grew, and then coalesced through tearing, leading to a reduction of fatigue life. Results revealed that the fatigue lives of UNSM-treated specimens were longer than those of the untreated specimens.

Conceptual design study FY 1981: synfuels from fusion - using the tandem mirror reactor and a thermochemical cycle to produce hydrogen

International Nuclear Information System (INIS)

Krikorian, O.H.

1982-01-01

This report represents the second year's effort of a scoping and conceptual design study being conducted for the express purpose of evaluating the engineering potential of producing hydrogen by thermochemical cycles using a tandem mirror fusion driver. The hydrogen thus produced may then be used as a feedstock to produce fuels such as methane, methanol, or gasoline. The main objective of this second year's study has been to obtain some approximate cost figures for hydrogen production through a conceptual design study

Studies on displacement behavior between hydrogen and deuterium in hydride column

International Nuclear Information System (INIS)

Lu Guangda; Li Gan; Jiang Guoqiang

2001-01-01

A series displacement experiments between hydrogen and deuterium in ZrCo, LaNi 5 , LaNi 4.7 Al 0.3 and Pd hydride column had been conducted at room temperature about. Results indicate that displacement characteristics related to factors such as temperature, gas flow rate, ratio surface area of solid phase and hydrogen isotope separation factor of the metal-hydrogen system. The palladium hydride have the best displacement characteristics, and LaNi 5 , LaNi 4.7 Al 0.3 and ZrCo are in the next places. Theoretical study reveals that the rule of the exchange reaction of hydrogen isotopes in gas-solid interface determines the displacement behavior and the displacing efficiency depends on exchange rate. The ideal stage mode could be used to describe the displacement breakthrough curve. The height equivalent to theoretical place (HETP) indicates the displacing effects. Also, the separation factor has a serious influence to HETP under the same condition

Performance Improvement of V-Fe-Cr-Ti Solid State Hydrogen Storage Materials in Impure Hydrogen Gas.

Science.gov (United States)

Ulmer, Ulrich; Oertel, Daria; Diemant, Thomas; Bonatto Minella, Christian; Bergfeldt, Thomas; Dittmeyer, Roland; Behm, R Jürgen; Fichtner, Maximilian

2018-01-17

Two approaches of engineering surface structures of V-Ti-based solid solution hydrogen storage alloys are presented, which enable improved tolerance toward gaseous oxygen (O 2 ) impurities in hydrogen (H 2 ) gas. Surface modification is achieved through engineering lanthanum (La)- or nickel (Ni)-rich surface layers with enhanced cyclic stability in an H 2 /O 2 mixture. The formation of a Ni-rich surface layer does not improve the cycling stability in H 2 /O 2 mixtures. Mischmetal (Mm, a mixture of La and Ce) agglomerates are observed within the bulk and surface of the alloy when small amounts of this material are added during arc melting synthesis. These agglomerates provide hydrogen-transparent diffusion pathways into the bulk of the V-Ti-Cr-Fe hydrogen storage alloy when the remaining oxidized surface is already nontransparent for hydrogen. Thus, the cycling stability of the alloy is improved in an O 2 -containing hydrogen environment as compared to the same alloy without addition of Mm. The obtained surface-engineered storage material still absorbs hydrogen after 20 cycles in a hydrogen-oxygen mixture, while the original material is already deactivated after 4 cycles.

Environmental Fatigue Behaviors of CF8M Stainless Steel in 310 .deg. C Deoxygenated Water - Effects of Hydrogen and Microstructure

Energy Technology Data Exchange (ETDEWEB)

Jang, Hun; Cho, Pyungyeon; Jang, Changheui [KAIST, Daejeon (Korea, Republic of); Kim, Tae Soon [Korea Hydro and Nuclear Power Corporation, Seoul (Korea, Republic of)

2014-01-15

The effects of environment and microstructure on low cycle fatigue (LCF) behaviors of CF8M stainless steels containing 11% of ferrites were investigated in a 310 .deg. C deoxygenated water environment. The reduction of LCF life of CF8M in a 310 .deg. C deoxygenated water was smaller than 316LN stainless steels. Based on the microstructure and fatigue surface analyses, it was confirmed that the hydrogen induced cracking contributed to the reduction in LCF life for CF8M as well as for 316LN. However, many secondary cracks were found on the boundaries of ferrite phases in CF8M, which effectively reduced the stress concentration at the crack tip. Because of the reduced stress concentration, the accelerated fatigue crack growth by hydrogen induced cracking was less significant, which resulted in the smaller environmental effects for CF8M than 316LN in a 310 .deg. C deoxygenated water.

Investigation for GOTHIC-3D prediction capability for the local hydrogen behavior analysis in the NPP containment

International Nuclear Information System (INIS)

Lee, Un-jang; Park, Goon-cherl

2002-01-01

Under a severe accident condition, hydrogen can be generated mainly from the reaction of zirconium cladding with hot steam and flammable hydrogen/air/steam mixtures can be formed. Thus hydrogen analysis is needed for a variety of reasons in the containment building; to predict the global containment response against the threat potential by hydrogen; to address certain safety issues such as the safety feature survivability due to global burning or explosion of hydrogen; or for designing and positioning of the hydrogen controller. In this study an analytical tool was used to predict the local hydrogen behavior in a small compartment and its analytical capability was examined through verification tests, which have been performed in SNU hydrogen mixing facilities. The analytical tool that was employed is the code GOTHIC which is a 3D three-fields (vapor, liquid and droplets) code specially developed for the containment analysis, and has the additional capability of modeling a number of different gases as well as air. The comparison between experimental and analytical tests results showed that the GOTHIC code is not applicable for the analysis of local hydrogen behavior in the highly transient condition and/or in small size compartment. (authors)

Hydrogen storage in binary and ternary Mg-based alloys. A comprehensive experimental study

Energy Technology Data Exchange (ETDEWEB)

Kalisvaart, W.P.; Harrower, C.T.; Haagsma, J.; Zahiri, B.; Luber, E.J.; Ophus, C.; Miltin, D. [Alberta Univ., Edmonton (Canada); Poirier, E.; Fritzsche, H. [Canadian Neutron Beam Centre, Chalk River, ON (Canada)

2010-07-01

This study focuses on hydrogen sorption properties of cosputtered 1.5 micrometer thick Mg-based films with Al, Fe and Ti as alloying elements. We show that ternary Mg-Al-Ti and Mg-Fe-Ti alloys in particular display remarkable sorption behavior: at 200 C, the films are capable of absorbing 4-6 wt.% hydrogen in seconds, and desorbing in minutes. Furthermore, this sorption behavior is stable for over 100 ab- and desorption cycles for Mg-Al-Ti and Mg-Fe-Ti alloys. No degradation in capacity or kinetics is observed. Based on these observations, some general design principles for Mg-based hydrogen storage alloys are suggested. For Mg-Fe-Ti, encouraging preliminary results on multilayered systems are also presented. (orig.)

Metal hydrides for hydrogen storage in nickel hydrogen batteries

International Nuclear Information System (INIS)

Bittner, H.F.; Badcock, C.C.; Quinzio, M.V.

1984-01-01

Metal hydride hydrogen storage in nickel hydrogen (Ni/H 2 ) batteries has been shown to increase battery energy density and improve battery heat management capabilities. However the properties of metal hydrides in a Ni/H 2 battery environment, which contains water vapor and oxygen in addition to the hydrogen, have not been well characterized. This work evaluates the use of hydrides in Ni/H 2 batteries by fundamental characterization of metal hydride properties in a Ni/H 2 cell environment. Hydrogen sorption properties of various hydrides have been measured in a Ni/H 2 cell environment. Results of detailed thermodynamic and kinetic studies of hydrogen sorption in LaNi 5 in a Ni/H 2 cell environment are presented. Long-term cycling studies indicate that degradation of the hydride can be minimized by cycling between certain pressure limits. A model describing the mechanism of hydride degradation is presented

Hydrogen production using the waste heat of Benchmark pressurized Molten carbonate fuel cell system via combination of organic Rankine cycle and proton exchange membrane (PEM) electrolysis

International Nuclear Information System (INIS)

Nami, Hossein; Akrami, Ehsan; Ranjbar, Faramarz

2017-01-01

Highlights: • Waste heat of the Benchmark system recovered using an ORC. • An integrated system is proposed to produce power and hydrogen. • The effects of some decision parameters on the produced hydrogen have investigated. - Abstract: Energy and exergy analyses are carried out for hydrogen production via combination of Benchmark system and organic Rankine cycle (ORC) coupled with a proton exchange membrane electrolyzer. A parametric study is reported and effects of such organic Rankine cycle significant variables as evaporator temperature, pinch point temperature difference in the evaporator and degree of superheat at the ORC turbine inlet on the rate of produced hydrogen, sustainability index, overall exergy efficiency and organic Rankine cycle net produced power are investigated. It is observed that the rate of produced hydrogen and overall exergy efficiency of the proposed combined system take the maximum value to change in the evaporator temperature. Also, it is revealed that increasing the pinch point temperature difference in the evaporator decreases the rate of produced hydrogen and the overall exergy efficiency of the system. Furthermore, the effects on the rate of produced hydrogen and the overall exergy efficiency of the degree of superheat at the ORC turbine inlet are the same as the effect of pinch point temperature difference.

Economic Cycles in a Behavioral Disequilibrium Perspective

DEFF Research Database (Denmark)

Mosekilde, Erik; Sterman, J.D.

1997-01-01

The paper reviews the characteristic features of the main economic cycles and discusses the behavioral foundation for each mode at the microlevel. The analysis continues to illustrate some of the nonlinear dynamic phenomena that can arise through interaction between the various modes and through...

Magnetic refrigerator for hydrogen liquefaction

Energy Technology Data Exchange (ETDEWEB)

Numazawa, T [National Institute for Materials Science, Tsukuba (Japan); Kamlya, K. [Japan Atomic Energy Agency, Naka (Japan); Utaki, T. [Osaka University, Osaka (Japan); Matsumoto, K. [Kanazawa University, Kanazawa (Japan)

2013-06-15

This paper reviews the development status of magnetic refrigeration system for hydrogen liquefaction. There is no doubt that hydrogen is one of most important energy sources in the near future. In particular, liquid hydrogen can be utilized for infrastructure construction consisting of storage and transportation. Liquid hydrogen is in cryogenic temperatures and therefore high efficient liquefaction method must be studied. Magnetic refrigeration which uses the magneto-caloric effect has potential to realize not only the higher liquefaction efficiency > 50 %, but also to be environmentally friendly and cost effective. Our hydrogen magnetic refrigeration system consists of Carnot cycle for liquefaction stage and AMR (active magnetic regenerator) cycle for precooling stages. For the Carnot cycle, we develop the high efficient system > 80 % liquefaction efficiency by using the heat pipe. For the AMR cycle, we studied two kinds of displacer systems, which transferred the working fluid. We confirmed the AMR effect with the cooling temperature span of 12 K for 1.8 T of the magnetic field and 6 second of the cycle. By using the simulation, we estimate the total efficiency of the hydrogen liquefaction plant for 10 kg/day. A FOM of 0.47 is obtained in the magnetic refrigeration system operation temperature between 20 K and 77 K including LN2 work input.

Numerical Study on Hydrogen Flow Behavior in Two Compartments with Different Connecting Pipes

Directory of Open Access Journals (Sweden)

HanChen Liu

2017-01-01

Full Text Available Hydrogen accumulation in the containment compartments under severe accidents would result in high concentration, which could lead to hydrogen deflagration or detonation. Therefore, getting detailed hydrogen flow and distribution is a key issue to arrange hydrogen removal equipment in the containment compartments. In this study, hydrogen flow behavior in local compartments has been investigated in two horizontal compartments. The analysis model is built by 3-dimensional CFD code in Cartesian coordinates based on the connection structure of the Advanced Pressurized Water Reactor (PWR compartments. It consists of two cylindrical vessels, representing the Steam Generator compartment (SG and Core Makeup Tank compartment (CMT. With standard k-ε turbulence model, the effects of the connecting pipe size and location on hydrogen concentration distribution are investigated. Results show that increasing the diameter of connection pipe (IP which is located at 800 mm from 150 mm to 300 mm facilitates hydrogen flow between compartments. Decreasing the length of IP which is located at 800 mm from 1000 mm to 500 mm can also facilitate hydrogen flow between compartments. Lower IP is in favor of hydrogen mixing with air in non-source compartment. Higher IP is helpful for hydrogen flow to the non-source term compartment from source term compartment.

Thermodynamic analysis of a nuclear-hydrogen power system using H2/O2 direct combustion product as a working substance in the bottom cycle

International Nuclear Information System (INIS)

Chen, D.Z.; Yu, C.P.

1990-01-01

A combined thermodynamic cycle using nuclear and hydrogen energy as heat sources was investigated in this paper. The cycle is composed of top cycle using HTGR as energy source and helium as working medium and a bottom cycle with H 2 /O 2 direct combustion product as working substance. hydrogen and oxygen are thermochemically by splitting of water produced through a part of nuclear heat recovered from the top cycle. They may be delivered to the O 2 /H 2 users or used as fuels for the high temperature bottom Rankine steam cycle. The combined cycle not only uses the new energy sources instead of conventional fossil fuels but it possess the advantages of both helium and steam cycle. It has a high thermal efficiency, large unit capacity, many-sided usage and less pollution. It may represent a new type of combined cycles for future energy conversion and power generation. Using computer diagram, a variety of schemes were calculated and analyzed. The influence of some main parameters upon the cycle performance were also studied

Electric field cycling behavior of ferroelectric hafnium oxide.

Science.gov (United States)

Schenk, Tony; Schroeder, Uwe; Pešić, Milan; Popovici, Mihaela; Pershin, Yuriy V; Mikolajick, Thomas

2014-11-26

HfO2 based ferroelectrics are lead-free, simple binary oxides with nonperovskite structure and low permittivity. They just recently started attracting attention of theoretical groups in the fields of ferroelectric memories and electrostatic supercapacitors. A modified approach of harmonic analysis is introduced for temperature-dependent studies of the field cycling behavior and the underlying defect mechanisms. Activation energies for wake-up and fatigue are extracted. Notably, all values are about 100 meV, which is 1 order of magnitude lower than for conventional ferroelectrics like lead zirconate titanate (PZT). This difference is mainly atttributed to the one to two orders of magnitude higher electric fields used for cycling and to the different surface to volume ratios between the 10 nm thin films in this study and the bulk samples of former measurements or simulations. Moreover, a new, analog-like split-up effect of switching peaks by field cycling is discovered and is explained by a network model based on memcapacitive behavior as a result of defect redistribution.

Hydrogen or Fossil Combustion Nuclear Combined Cycle Systems for Baseload and Peak Load Electricity Production. Annex X

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-12-15

A combined cycle power plant is described that uses: (i) heat from a high temperature nuclear reactor to meet baseload electrical demands; and (ii) heat from the same high temperature reactor and burning natural gas, jet fuel or hydrogen to meet peak load electrical demands. For baseload electricity production, fresh air is compressed, then flows through a heat exchanger, where it is heated to between 700 and 900{sup o}C by using heat provided by a high temperature nuclear reactor via an intermediate heat transport loop, and finally exits through a high temperature gas turbine to produce electricity. The hot exhaust from the Brayton cycle gas turbine is then fed to a heat recovery steam generator that provides steam to a steam turbine for added electrical power production. To meet peak electricity demand, the air is first compressed and then heated with the heat from a high temperature reactor. Natural gas, jet fuel or hydrogen is then injected into the hot air in a combustion chamber, combusts and heats the air to 1300{sup o}C - the operating conditions for a standard natural gas fired combined cycle plant. The hot gas then flows through a gas turbine and a heat recovery steam generator before being sent to the exhaust stack. The higher temperatures increase the plant efficiency and power output. If hydrogen is used, it can be produced at night using energy from the nuclear reactor and stored until required. With hydrogen serving as the auxiliary fuel for peak power production, the electricity output to the electrical grid can vary from zero (i.e. when hydrogen is being produced) to the maximum peak power while the nuclear reactor operates at constant load. As nuclear heat raises air temperatures above the auto-ignition temperatures of the various fuels and powers the air compressor, the power output can be varied rapidly (compared with the capabilities of fossil fired turbines) to meet spinning reserve requirements and stabilize the electrical grid. This combined

Research on the surface chemical behavior of uranium metal in hydrogen atmosphere by XPS

International Nuclear Information System (INIS)

Fu Xiaoguo; Wang Xiaolin; Yu Yong; Zhao Zhengping

2001-01-01

The surface chemical behavior clean uranium metal in hydrogen atmosphere at 100 and 200 degree C is studied by X-ray photoelectron spectroscopy (XPS), respectively. It leads to hydriding reaction when the hydrogen exposure is 12.0 Pa·s, and the U4f 7/2 binding energy of UH 3 is found to be 378.7 eV. The higher temperature (200 degree C) is beneficial to UH 3 formation at the same hydrogen exposures. XPS elemental depth profiles indicate that the distribution of uranium surface layer is UO 2 , UH 3 and U after exposure to 174.2 Pa·s hydrogen

Emergence of a High-Temperature Superconductivity in Hydrogen Cycled pd Compounds as AN Evidence for Superstoihiometric H/d Sites

Science.gov (United States)

Lipson, Andrei; Castano, Carlos; Miley, George; Lipson, Andrei; Lyakhov, Boris; Mitin, Alexander

2006-02-01

Transport and magnetic properties of hydrogen cycled PdHx and Pd/PdO:Hx (x ~ (4/6) × 10-4) nano-composite consisting of a Pd matrix with hydrogen trapped inside dislocation cores have been studied. The results suggest emergence of a high-temperature superconductivity state of a condensed hydrogen phase confined inside deep dislocation cores in the Pd matrix. The possible role of hydrogen/deuterium filled dislocation nano-tubes is discussed. These dislocation cores could be considered as active centers of LENR triggering due to (i) short D-D separation distance (~Bohr radius); (ii) high-local D-loading in the Pd and the corresponding effective lattice compression; (iii) a large optic phonon energy resulting in a most effective lattice-nuclei energy transfer.

Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen battery cells

Science.gov (United States)

Smithrick, John J.; Hall, Stephen W.

1990-01-01

An advanced 125 Ah individual pressure vessel (IPV) nickel-hydrogen cell was designed. The primary function of the advanced cell is to store and deliver energy for long-term, low earth-orbit (LEO) spacecraft missions. The new features of this design are: (1) use of 26 percent rather than 31 percent potassium hydroxide (KOH) electrolyte, (2) use of a patented catalyzed wall wick, (3) use of serrated-edge separators to facilitate gaseous oxygen and hydrogen flow within the cell, while still maintaining physical contact with the wall wick for electrolyte management, and (4) use of a floating rather than a fixed stack (state-of-the-art) to accommodate nickel electrode expansion. Six 125-Ah flight cells based on this design were fabricated by Eagle-Picher. Three of the cells contain all of the advanced features (test cells) and three are the same as the test cells except they don't have catalyst on the wall wick (control cells). All six cells are in the process of being evaluated in a LEO cycle life test. The cells have accumulated about 4700 LEO cycles (60 percent DOD 10 C). There have been no cell failures; the catalyzed wall wick cells, however, are performing better.

Hydrogen permeation and corrosion behavior of high strength steel MCM 430 in cyclic wet-dry SO2 environment

International Nuclear Information System (INIS)

Nishimura, Rokuro; Shiraishi, Daisuke; Maeda, Yasuaki

2004-01-01

Hydrogen permeation caused by corrosion under a cyclic wet (2 h)-dry (10 h) SO 2 condition was investigated for a high strength steel of MCM 430 by using an electrochemical technique in addition to the corrosion behavior obtained from weight loss measurement and the determination of corrosion products by using X-ray diffraction method. The hydrogen content converted from hydrogen permeation current density was observed in both wet and dry periods. The origin of proton was estimated to be from (1) the hydrolysis of ferrous ions, (2) the oxidation of ferrous ions and ferrous hydroxide, and (3) hydrolysis of SO 2 and formation of FeSO 4 , but not from the dissociation of H 2 O. With respect to the determination of the corrosion products consisting of inner (adherent) and outer (not adherent) layers, the outer layer is composed of α-FeOOH, amorphous phase and γ-FeOOH, where α-FeOOH increases with the increase in the wet-dry cycle, and amorphous phase shows the reverse trend. The corrosion product in the inner layer is mainly Fe 3 O 4 with them. On the basis of the results obtained, the role of the dry or wet period, the effect of SO 2 and the corrosion process during the cyclic wet-dry periods were discussed

A grey-based group decision-making methodology for the selection of hydrogen technologiess in Life Cycle Sustainability perspective

DEFF Research Database (Denmark)

Manzardo, Alessandro; Ren, Jingzheng; Mazzi, Anna

2012-01-01

The objective of this research is to develop a grey-based group decision-making methodology for the selection of the best renewable energy technology (including hydrogen) using a life cycle sustainability perspective. The traditional grey relational analysis has been modified to better address...... the issue of uncertainty. The proposed methodology allows multi-person to participate in the decision-making process and to give linguistic evaluation on the weights of the criteria and the performance of the alternative technologies. In this paper, twelve hydrogen production technologies have been assessed...... using the proposed methodology, electrolysis of water technology by hydropower has been considered to be the best technology for hydrogen production according to the decision-making group....

Bifurcation behavior during the hydrogen production in two compatible configurations of a novel circulating fluidized bed membrane reformer

International Nuclear Information System (INIS)

Chen, Z.; Elnashaie, S.S.

2004-01-01

'Full text:' Multiplicity of steady states (Static Bifurcation Behavior, SBB) in a novel Circulating Fluidized Bed (CFB) membrane reformer for the efficient production of hydrogen by steam reforming of heptane (model component of heavy hydrocarbons and renewable bio-oils) is investigated. The present paper highlights the practical implications of this phenomenon on the behavior of this novel reformer with special focusing on hydrogen production. Two configurations are considered and compared. One is with the catalyst regeneration before the gas-solid separation and the other one is with the catalyst regeneration after the gas-solid separation. Multiplicity of the steady states prevails over a number of design and operating parameters with important impact on the reformer performance. The basis of process evaluation is focused on the net hydrogen production. The dependence of the behavior of this autothermal CFB is shown to be quite complex and defy the simple logic of non-autothermal processes. The unit can be a very efficient hydrogen producer provided its bifurcation behavior is well understood and correctly exploited. (author)

Passivation behavior of AB{sub 5}-type hydrogen storage alloys for battery electrode application

Energy Technology Data Exchange (ETDEWEB)

Meli, F. [Fribourg Univ. (Switzerland). Inst. de Physique; Sakai, T. [Fribourg Univ. (Switzerland). Inst. de Physique; Zuettel, A. [Fribourg Univ. (Switzerland). Inst. de Physique; Schlapbach, L. [Fribourg Univ. (Switzerland). Inst. de Physique

1995-04-15

In many applications, AB{sub 5} type hydrogen storage alloys show passivation behavior, i.e. when fully discharged, metal hydride electrodes show (especially at higher temperatures) a decrease in activity and therefore a decrease in capacity at normal discharge currents for ensuing cycles. Passivation may continue to the point where activity becomes so low that the capacity is no longer accessible. Electrochemical measurements were taken of two different AB{sub 5}-type alloys, one with manganese and one without manganese (LaNi{sub 3.4}Co{sub 1.2}Al{sub 0.4} and LaNi{sub 3.4}Co{sub 1.2}Al{sub 0.3}Mn{sub 0.1}). Both alloys showed passivation behavior after remaining in the discharged state. The alloy with manganese showed a stronger tendency to passivation which is in contradiction with earlier observations. Photoelectron spectroscopic analysis together with sputter depth profiling was used to investigate the surface composition of samples which had undergone different surface pretreatments. Surface analysis of electrodes in the passivated state shows a lower content of metallic nickel and a thicker nickel surface oxide film. We attribute the low electrochemical kinetics of the alloys after passivation to the loss of metallic nickel and/or cobalt at the electrode-electrolyte interface. ((orig.))

Resistivity and strain behavior during transformation cycling in nickel-titanium

International Nuclear Information System (INIS)

Lee, K.H.

1983-09-01

The effects of stress and transformation fatigue cycling on the resistivity and strain behaviors in Ni-Ti wires were studied. The samples consisted of uncycled wires and wires cycled 5.78 million times in shape memory heat engine devices. Measurements of resistivity and strain were made as a function of temperature at various applied uniaxial tensile stresses. The resistivity-temperature and strain-temperature behaviors were observed to depend on the temperature or the portion of the transformation cycle at which the stress change is made. It was found that the low temperature resistivity and strain increased with increasing stress. Also, the transformation fatigue cycled wires showed a higher and broader resistivity peak with two-stage behavior. The increase in strain with increasing stress is explained in terms of the crystallographic multiplicity of martensite plates and the alteration of the martensite plate structure in response to the applied stress. Prior transformation fatigue cycling causes a decrease in the applied stress dependence of the total strain changes. Also, the shape of curve is changed upon annealing and the M/sub S/ temperature is lowered by transformation fatigue cycling. The lower M/sub S/ temperature upon cycling is due to a stabilization of the high-temperature phase due to transformation-induced dislocations acting as an impediment to further martensite nucleation. Another effect of the stress is to increase the resistivity of the low-temperature phase. However, it was noticed that the stress should be increased above M/sub S/ temperature to increase the resistivity of the low temperature phase. The increase in low-temperature resistivity is partially due to the change in form factor during transformation shape change and due to the alteration of the martensite variants in a preferred direction

Thermodynamic analysis of SCW NPP cycles with thermo-chemical co-generation of hydrogen

International Nuclear Information System (INIS)

Naidin, N.; Mokry, S.; Monichan, R.; Chophla, K.; Pioro, I.; Naterer, G.; Gabriel, K.

2009-01-01

Research activities are currently conducted worldwide to develop Generation IV nuclear reactor concepts with the objective of improving thermal efficiency and increasing economic competitiveness of Generation IV Nuclear Power Plants (NPPs) compared to modern thermal power plants. The Super-Critical Water-cooled Reactor (SCWR) concept is one of the six Generation IV options chosen for further investigation and development in several countries including Canada and Russia. Water-cooled reactors operating at subcritical pressures (10 - 16 MPa) have provided a significant amount of electricity production for the past 50 years. However, the thermal efficiency of the current NPPs is not very high (30 - 35%). As such, more competitive designs, with higher thermal efficiencies, which will be close to that of modern thermal power plants (45 - 50%), need to be developed and implemented. Super-Critical Water (SCW) NPPs will have much higher operating parameters compared to current NPPs (i.e., steam pressures of about 25 MPa and steam outlet temperatures up to 625 o C). Furthermore, SCWRs operating at higher temperatures can facilitate an economical co-generation of hydrogen through thermochemical cycles (particularly, the copper-chlorine cycle) or direct high-temperature electrolysis. The two SCW NPP cycles proposed by this paper are based on direct, regenerative, no-reheat and single-reheat configurations. As such, the main parameters and performance in terms of thermal efficiency of the SCW NPP concepts mentioned above are being analyzed. The cycles are generally comprised of: an SCWR, a SC turbine, one deaerator, ten feedwater heaters, and pumps. The SC turbine of the no-reheat cycle consists of one High-Pressure (HP) cylinder and two Low-Pressure (LP) cylinders. Alternatively, the SC turbine for the single-reheat cycle is comprised of one High-Pressure (HP) cylinder, one Intermediate-Pressure (IP) cylinder and two Low-Pressure (LP) cylinders. Since the single-reheat option

Effect of light-dark cycles on hydrogen and poly-β-hydroxybutyrate production by a photoheterotrophic culture and Rhodobacter capsulatus using a dark fermentation effluent as substrate.

Science.gov (United States)

Montiel Corona, Virginia; Le Borgne, Sylvie; Revah, Sergio; Morales, Marcia

2017-02-01

A Rhodobacter capsulatus strain and a photoheterotrophic culture (IZT) were cultivated to produce hydrogen under different light-dark cycles. A dark fermentation effluent (DFE) was used as substrate. It was found that IZT culture had an average cumulative hydrogen production (Paccum H 2 ) of 1300±43mLH 2 L -1 under continuous illumination and light-dark cycles of 30 or 60min. In contrast, R. capsulatus reduced its Paccum H 2 by 20% under 30:30min light-dark cycles, but tripled its poly-β-hydroxybutyrate (PHB) content (308±2mgPHB gdw -1 ) compared to continuous illumination. The highest PHB content by IZT culture was 178±10mgPHB gdw -1 under 15:15min light-dark cycles. PCR-DGGE analysis revealed that the IZT culture was mainly composed of Rhodopseudomonas palustris identified with high nucleotide similarity (99%). The evaluated cultures might be used for hydrogen and PHB production. They might provide energy savings by using light-dark cycles and DFE valorization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of the hybrid copper oxide-copper sulfate cycle for the thermochemical splitting of water for hydrogen production

International Nuclear Information System (INIS)

Gonzales, Ross B.; Law, Victor J.; Prindle, John C.

2009-01-01

The hybrid copper oxide-copper sulfate water-splitting thermochemical cycle involves two principal steps: (1) hydrogen production from the electrolysis of water, SO 2 (g) and CuO(s) at room temperature and (2) the thermal decomposition of the CuSO 4 product to form oxygen and SO 2 , which is recycled to the first step. A four-reaction version of the cycle (known in the literature as Cycle H-5) was used as the basis of the present work. For several of the four reactions, a rotating batch reactor sequence is proposed in order to overcome equilibrium limitations. Pinch technology was used to optimize heat integration. Sensitivity analyses revealed it to be economically more attractive to use a 10 C approach to minimize heat loss (rather than 20 C). Using standard Aspen Plus features and the Peng-Robinson equation of state for separations involving oxygen and sulfur oxides, a proposed flowsheet for the cycle was generated to yield ''Level 3'' results. A cost analysis of the designed plant (producing 100 million kmol/yr hydrogen) indicates a total major equipment cost of approximately $45 million. This translates to a turnkey plant price (excluding the cost of the high-temperature heat source or electrolyzer internals) of approximately $360 million. Based on a $2.50/kg selling price for hydrogen, gross annual revenue could be on the order of $500 million, resulting in a reasonable payback period when all capital and operating costs are considered. Previous efficiency estimates using Level 1 and Level 2 methods gave the process efficiency in the neighborhood of 47-48%. The Level 3 efficiency computation was 24-25% depending on the approach temperature used for recuperation. If the low quality heat rejected by the process can be recovered and used elsewhere, the Level 3 analysis could be as high as 51-53%. (author)

Vehicle driving cycle performance of the spark-less di-ji hydrogen engine

Energy Technology Data Exchange (ETDEWEB)

Boretti, Alberto A. [School of Science and Engineering, University of Ballarat, PO Box663, Ballarat, VIC 3353 (Australia)

2010-05-15

The paper describes coupled CFD combustion simulations and CAE engine performance computations to describe the operation over the full range of load and speed of an always lean burn, Direct Injection Jet Ignition (DI-JI) hydrogen engine. Jet ignition pre-chambers and direct injection are enablers of high efficiencies and load control by quantity of fuel injected. Towards the end of the compression stroke, a small quantity of hydrogen is injected within the spark-less pre-chamber of the DI-JI engine, where it mixes with the air entering from the main chamber and auto-ignites because of the high temperature of the hot glow plug. Then, jets of partially combusted hot gases enter the main chamber igniting there in the bulk, over multiple ignition points, lean stratified mixtures of air and fuel. Engine maps of brake specific fuel consumption vs. speed and brake mean effective pressure are computed first. CAE vehicle simulations are finally performed evaluating the fuel consumption over emission cycles of a vehicle equipped with this engine. (author)

Macroenvironmental regulation of hair cycling and collective regenerative behavior.

Science.gov (United States)

Plikus, Maksim V; Chuong, Cheng-Ming

2014-01-01

The hair follicle (HF) regeneration paradigm provides a unique opportunity for studying the collective behavior of stem cells in living animals. Activation of HF stem cells depends on the core inhibitory BMP and activating WNT signals operating within the HF microenvironment. Additionally, HFs receive multilayered signaling inputs from the extrafollicular macroenvironment, which includes dermis, adipocytes, neighboring HFs, hormones, and external stimuli. These activators/inhibitors are integrated across multiple stem-cell niches to produce dynamic hair growth patterns. Because of their pigmentation, these patterns can be easily studied on live shaved animals. Comparing to autonomous regeneration of one HF, populations of HFs display coupled decision making, allowing for more robust and adaptable regenerative behavior to occur collectively. The generic cellular automata model used to simulate coordinated HF cycling here can be extended to study population-level behavior of other complex biological systems made of cycling elements.

Hydrogen production through microheterogeneous photocatalysis of hydrogen sulfide cleavage. The thiosulfate cycle

Energy Technology Data Exchange (ETDEWEB)

Borgarello, E; Serpone, N; Graetzel, M; Pelizzetti, E

1985-01-01

Cleavage of hydrogen sulfide into hydrogen and sulfur occurs in alkaline aqueous CdS dispersions under visible light illumination. Small quantities of a noble metal catalyst (RuO/sub 2/) loaded onto 'naked' CdS particles markedly improve the yield of hydrogen formation. The effect of RuO/sub 2/ is ascribed to catalysis of electron transfer to proton. Simultaneous and efficient photogeneration of hydrogen and thiosulfate occurs in CdS dispersions containing both sulfite and bisulfide (or sulfide) ions. Electron transfer from the conduction band of CdS to that of TiO/sub 2/ particles occurs in alkaline suspensions containing these HS/sup -/ ions and has been exploited to improve the performance of a system achieving decomposition of H/sub 2/S by visible light. Equally important is a recent finding that the performance of a system containing 'naked' CdS in combination with RuO/sub 2/-loaded TiO/sub 2/ particles is far better than that of CdS/RuO/sub 2/ alone. Additionally, conduction band electrons produced by bandgap excitation of TiO/sub 2/ particles efficiently reduce thiosulfate to sulfide and sulfite. The valence band process in alklaine TiO/sub 2/ dispersions is thought to involve oxidation of S/sub 2/O/sub 3//sup 2 -/ to tetrathionate, S/sub 4/O/sub 6//sup 2 -/, which quantitatively dismutates into sulfite and thiosulfate. The photodriven disproportionation of thiosulfate into sulfide and sulfate is of great interest in systems that photochemically cleave hydrogen sulfide into hydrogen and sulfur. (author).

Evidence of superstoichiometric H/D LENR active sites and high-temperature superconductivity in a hydrogen-cycled Pd/PdO

International Nuclear Information System (INIS)

Lipson, A.G.; Castano, C.H.; Miley, G.H.; Lyakhov, B.F.; Tsivadze, A.Yu.; Mitin, A.V.

2006-01-01

Electron transport and magnetic properties have been studied in a 12.5 μm thick Pd foil with a thermally grown oxide and a low-residual concentration of hydrogen. This foil was deformed by cycling across the Pd hydride miscibility gap and the residual hydrogen was trapped at dislocation cores. Anomalies of both resistance and magnetic susceptibility have been observed below 70 K, indicating the appearance of excess conductivity and a diamagnetic response that we interpret in terms of filamentary superconductivity. These anomalies are attributed to a condensed hydrogen-rich phase at dislocation cores. The role of deuterium rich dislocation cores as LENR active sites is discussed. (author)

Evidence of Superstoichiometric H/d Lenr Active Sites and High-Temperature Superconductivity in a Hydrogen-Cycled Pd/PdO

Science.gov (United States)

Lipson, A. G.; Castano, C. H.; Miley, G. H.; Lyakhov, B. F.; Tsivadze, A. Yu.; Mitin, A. V.

Electron transport and magnetic properties have been studied in a 12.5 μm thick Pd foil with a thermally grown oxide and a low-residual concentration of hydrogen. This foil was deformed by cycling across the Pd hydride miscibility gap and the residual hydrogen was trapped at dislocation cores. Anomalies of both resistance and magnetic susceptibility have been observed below 70 K, indicating the appearance of excess conductivity and a diamagnetic response that we interpret in terms of filamentary superconductivity. These anomalies are attributed to a condensed hydrogen-rich phase at dislocation cores. The role of deuterium rich dislocation cores as LENR active sites is discussed.

Thermal desorption spectroscopy for investigating hydrogen isotope behavior in materials

International Nuclear Information System (INIS)

Xia Tirui; Yang Hongguang; Zhan Qin; Han Zhibo; He Changshui

2012-01-01

The behavior of hydrogen isotope generated in fusion reactor materials is the key issue for safety and economic operation of fusion reactors and becomes an interesting field. In order to investigate the mechanism of hydrogen isotope such as diffusion, release and retention, a high-sensitivity thermal desorption spectroscopy (TDS) in combination with a quadruple mass spectrometer (QMS) was developed. A major technical breakthrough in ultrahigh vacuum (UHV), low hydrogen background, linear heating and sensitivity calibration of TDS system was made. UHV of l × 10 -7 Pa and low hydrogen background of l × 10 -9 Pa were obtained by combining turbo molecule pump and sputter ion pump. Specimens can be linearly heated up to 1173 K at the rate of 1 to 50 K/min under the MCGS PID software. Sensitivity calibration of the TDS system was accomplished using a special deuterium leak in the detector mode of QMS second electron multiplier. The desorption sensitivity coefficient and the minimum detection limit of deuterium desorption rate are 6.22 × l0 24 s -l · and l.24 × l0 -10 s -1 , respectively. The measurement was also routinely conducted on a specimen of standard, deuterium-containing Zr-4 alloy maintained in the laboratory, so as to validate the TDS method. (authors)

Effect of chemical treatments on hydrogen storage behaviors of multi-walled carbon nanotubes

International Nuclear Information System (INIS)

Lee, Seul-Yi; Park, Soo-Jin

2010-01-01

In this work, the hydrogen storage behaviors of chemically treated multi-walled carbon nanotubes (MWNTs) were investigated. The surface properties of the functionalized MWNTs were confirmed by Fourier transfer infrared spectroscopy, X-ray diffraction, the Boehm titration method, and zeta-potential measurements. The hydrogen storage capacity of the MWNTs was evaluated at 298 K and 100 bar. In the experimental results, it was found that the chemical treatments introduced functional groups onto the MWNT surfaces. The amount of hydrogen storage was enhanced, by acidic surface treatment, to 0.42 wt.% in the acidic-treated MWNTs compared with 0.26 wt.% in the as-received MWNTs. Meanwhile, the basic surface treatment actually reduced the hydrogen storage capacity, to 0.24 wt.% in the basic-treated MWNTs sample. Consequently, it could be concluded that hydrogen storage is greatly influenced by the acidic characteristics of MWNT surfaces, resulting in enhanced electron acceptor-donor interaction at interfaces.

Analysis and optimal process development of the iodine-Sulfur cycle for nuclear hydrogen production

International Nuclear Information System (INIS)

Lee, Byung Jin

2009-02-01

Hydrogen is expected to be a main energy vector for the future society. Among many thermo-chemical water splitting technologies for mass production of hydrogen, Iodine-Sulfur (I-S) cycle is considered to be the most promising one. Originated in the 1980s by General Atomics in the United States, the I-S cycle utilizes high temperature heat from energy sources such as nuclear reactors. Despite its high viability relative to many other options, lots of technical challenges need to be resolved until it can practically contribute to the mass production of hydrogen. In the present work, based on the experimental data available from previous works and discussions collected through the literature survey, the optimal operating conditions were proposed for the Bunsen reaction, considering the key concerns of the I-S cycle: i.e., the liquid-liquid (L-L) phase separation performance, the water distributions between the sulfuric acid and poly-hydroiodic acid (HI x ) phases, the side reactions, and the operating cost due to the excess iodine and water. All the available experimental data were combined together, and a series of parametric studies were done to find out any trends among parameters. The optimal operating point is determined as 4 mol of excess iodine and 11 mol of excess water in the stoichiometry at temperature of 330K, while the allowable window ranges between 4∼6 mol for excess iodine, 11∼13 moles for excess water, and 330∼350K for temperature. As for the distribution of excess water after the Bunsen reaction and L-L phase separation, 5 mol moves to the sulfuric acid phase and 6∼8 mol to the HI x phase. By controlling the operation within this window, it should be possible to avoid the side reaction and iodine solidification, to increase the HI concentration well above the azeotrope in the HI x section, and to minimize the operating cost caused by the excess iodine and water. With the optimized Bunsen reaction process to yield an over-azeotropic HI liquid

Life cycle assessment of hydrogen production from S-I thermochemical process coupled to a high temperature gas reactor

Energy Technology Data Exchange (ETDEWEB)

Giraldi, M. R.; Francois, J. L.; Castro-Uriegas, D. [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac No. 8532, Col. Progreso, C.P. 62550, Jiutepec, Morelos (Mexico)

2012-07-01

The purpose of this paper is to quantify the greenhouse gas (GHG) emissions associated to the hydrogen produced by the sulfur-iodine thermochemical process, coupled to a high temperature nuclear reactor, and to compare the results with other life cycle analysis (LCA) studies on hydrogen production technologies, both conventional and emerging. The LCA tool was used to quantify the impacts associated with climate change. The product system was defined by the following steps: (i) extraction and manufacturing of raw materials (upstream flows), (U) external energy supplied to the system, (iii) nuclear power plant, and (iv) hydrogen production plant. Particular attention was focused to those processes where there was limited information from literature about inventory data, as the TRISO fuel manufacture, and the production of iodine. The results show that the electric power, supplied to the hydrogen plant, is a sensitive parameter for GHG emissions. When the nuclear power plant supplied the electrical power, low GHG emissions were obtained. These results improve those reported by conventional hydrogen production methods, such as steam reforming. (authors)

Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for super-stoichiometric H/D sites

International Nuclear Information System (INIS)

Lipson, Andrei; Castano, Carlos; Miley, George; Lipson, Andrei; Lyakhov, Boris; Mitin, Alexander

2006-01-01

Transport and magnetic properties of hydrogen cycled PdH x and Pd/PdO:H x (x ∼ = (4/6) x 10 -4 ) nano-composite consisting of a Pd matrix with hydrogen trapped inside dislocation cores have been studied. The results suggest emergence of a high-temperature superconductivity stale of a condensed hydrogen phase confined inside deep dislocation cores in the Pd matrix. The possible role of hydrogen/deuterium filled dislocation nano-tubes is discussed. These dislocation cores could be considered as active centers of LENR triggering due to (i) short D-D separation distance (∼Bohr radius); (ii) high-local D-loading in the Pd and the corresponding effective lattice compression; (iii) a large optic phonon energy resulting in a most effective lattice-nuclei energy transfer

Revisiting the Hydrogen Storage Behavior of the Na-O-H System

Directory of Open Access Journals (Sweden)

Jianfeng Mao

2015-04-01

Full Text Available Solid-state reactions between sodium hydride and sodium hydroxide are unusual among hydride-hydroxide systems since hydrogen can be stored reversibly. In order to understand the relationship between hydrogen uptake/release properties and phase/structure evolution, the dehydrogenation and hydrogenation behavior of the Na-O-H system has been investigated in detail both ex- and in-situ. Simultaneous thermogravimetric-differential thermal analysis coupled to mass spectrometry (TG-DTA-MS experiments of NaH-NaOH composites reveal two principal features: Firstly, an H2 desorption event occurring between 240 and 380 °C and secondly an additional endothermic process at around 170 °C with no associated weight change. In-situ high-resolution synchrotron powder X-ray diffraction showed that NaOH appears to form a solid solution with NaH yielding a new cubic complex hydride phase below 200 °C. The Na-H-OH phase persists up to the maximum temperature of the in-situ diffraction experiment shortly before dehydrogenation occurs. The present work suggests that not only is the inter-phase synergic interaction of protic hydrogen (in NaOH and hydridic hydrogen (in NaH important in the dehydrogenation mechanism, but that also an intra-phase Hδ+… Hδ– interaction may be a crucial step in the desorption process.

Early postnatal treatment with clomipramine induces female sexual behavior and estrous cycle impairment.

Science.gov (United States)

Molina-Jiménez, Tania; Limón-Morales, Ofelia; Bonilla-Jaime, Herlinda

2018-03-01

Administration of clomipramine (CMI), a tricyclic antidepressant, in early stages of development in rats, is considered an animal model for the study of depression. This pharmacological manipulation has induced behavioral and physiological alterations, i.e., less pleasure-seeking behaviors, despair, hyperactivity, cognitive dysfunction, alterations in neurotransmitter systems and in HPA axis. These abnormalities in adult male rats are similar to the symptoms observed in major depressive disorders. One of the main pleasure-seeking behaviors affected in male rats treated with CMI is sexual behavior. However, to date, no effects of early postnatal CMI treatment have been reported on female reproductive cyclicity and sexual behavior. Therefore, we explored CMI administration in early life (8-21 PN) on the estrous cycle and sexual behavior of adult female rats. Compared to the rats in the early postnatal saline treatment (CTRL group), the CMI rats had fewer estrous cycles, fewer days in the estrous stage, and longer cycles during a 20-day period of vaginal cytology analysis. On the behavioral test, the CMI rats displayed fewer proceptive behaviors (hopping, darting) and had lower lordosis quotients. Also, they usually failed to display lordosis and only rarely manifested marginal or normal lordosis. In contrast, the CTRL rats tended to display normal lordosis. These results suggest that early postnatal CMI treatment caused long-term disruptions of the estrous cycle and female sexual behavior, perhaps by alteration in the hypothalamic-pituitary-gonadal (HPG) axes and in neuronal circuits involved in the regulation of the performance and motivational of sexual behavior as the noradrenergic and serotonergic systems. Copyright © 2018 Elsevier Inc. All rights reserved.

Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

Science.gov (United States)

Wang, Guihua; Ogden, Joan M.; Chang, Daniel P. Y.

Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air quality

Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

International Nuclear Information System (INIS)

Guihua Wang; Ogden, Joan M.; Chang, Daniel P.Y.

2007-01-01

Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x ) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air

Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for super-stoichiometric H/D sites

Energy Technology Data Exchange (ETDEWEB)

Lipson, Andrei; Castano, Carlos; Miley, George [University of Illinois at Urbana - Champaign, lL (United States); Lipson, Andrei; Lyakhov, Boris [lnstitute of Physical Chemistry, RAS, Moscow (Russian Federation); Mitin, Alexander [P. Kapitza Institute for Physical Problems, RAS, Moscow (Russian Federation)

2006-07-01

Transport and magnetic properties of hydrogen cycled PdH{sub x} and Pd/PdO:H{sub x} (x {approx} = (4/6) x 10{sup -4}) nano-composite consisting of a Pd matrix with hydrogen trapped inside dislocation cores have been studied. The results suggest emergence of a high-temperature superconductivity stale of a condensed hydrogen phase confined inside deep dislocation cores in the Pd matrix. The possible role of hydrogen/deuterium filled dislocation nano-tubes is discussed. These dislocation cores could be considered as active centers of LENR triggering due to (i) short D-D separation distance ({approx}Bohr radius); (ii) high-local D-loading in the Pd and the corresponding effective lattice compression; (iii) a large optic phonon energy resulting in a most effective lattice-nuclei energy transfer.

Muscle fascicle behavior during eccentric cycling and its relation to muscle soreness.

Science.gov (United States)

Peñailillo, Luis; Blazevich, Anthony J; Nosaka, Kazunori

2015-04-01

A single bout of eccentric exercise confers a protective effect against muscle damage and soreness in subsequent eccentric exercise bouts, but the mechanisms underpinning this effect are unclear. This study compared vastus lateralis (VL) muscle-tendon behavior between two eccentric cycling bouts to test the hypothesis that muscle-tendon behavior would be different between bouts and would be associated with the protective effect. Eleven untrained men (27.1 ± 7.0 yr) performed two bouts of eccentric cycling (ECC1 and ECC2) separated by 2 wk for 10 min at 65% of maximal concentric workload (191.9 ± 44.2 W) each. Muscle soreness (by visual analog scale) and maximal voluntary isometric contraction (MVC) torque of the knee extensors were assessed before and 1-2 d after exercise. Using ultrasonography, VL fascicle length and angle changes during cycling were assessed, and tendinous tissue (TT) length changes were estimated. VL EMG amplitude, crank torque, and knee joint angles were measured during cycling. Soreness was greater (P tendon behavior may be an important mechanism underpinning the protective effect.

NASA Lewis advanced IPV nickel-hydrogen technology

Science.gov (United States)

Smithrick, John J.; Britton, Doris L.

1993-01-01

Individual pressure vessel (IPV) nickel-hydrogen technology was advanced at NASA Lewis and under Lewis contracts. Some of the advancements are as follows: to use 26 percent potassium hydroxide electrolyte to improve cycle life and performance, to modify the state of the art cell design to eliminate identified failure modes and further improve cycle life, and to develop a lightweight nickel electrode to reduce battery mass, hence reduce launch and/or increase satellite payload. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen battery cells was reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 accelerated LEO cycles at 80 percent DOD compared to 3,500 cycles for cells containing 31 percent KOH. Results of the boiler plate cell tests have been validated at NWSC, Crane, Indiana. Forty-eight ampere-hour flight cells containing 26 and 31 percent KOH have undergone real time LEO cycle life testing at an 80 percent DOD, 10 C. The three cells containing 26 percent KOH failed on the average at cycle 19,500. The three cells containing 31 percent KOH failed on the average at cycle 6,400. Validation testing of NASA Lewis 125 Ah advanced design IPV nickel-hydrogen flight cells is also being conducted at NWSC, Crane, Indiana under a NASA Lewis contract. This consists of characterization, storage, and cycle life testing. There was no capacity degradation after 52 days of storage with the cells in the discharged state, on open circuit, 0 C, and a hydrogen pressure of 14.5 psia. The catalyzed wall wick cells have been cycled for over 22,694 cycles with no cell failures in the continuing test. All three of the non-catalyzed wall wick cells failed (cycles 9,588; 13,900; and 20,575). Cycle life test results of the Fibrex nickel electrode has demonstrated the feasibility of an improved nickel electrode giving a higher specific energy nickel-hydrogen cell. A nickel-hydrogen boiler plate cell using an 80

MELCOR simulation of steam condensation effect on hydrogen behavior in THAI HM-2 experiment

Energy Technology Data Exchange (ETDEWEB)

Lee, Seongnyeon; Lee, Jung-Jae; Cho, Yong-Jin [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

2015-10-15

In this study, MELCOR simulation was carried out for THAI HM-2 experiment of OECD. As a results, stratification of hydrogen cloud was reasonably captured in MELCOR simulation. Furthermore, the pressure from simulation results in cases where mass transfer coefficient of MELCOR condensation model was modified was good agreement with the experimental results. Containment Filtered Ventilation System (CFVS) has been introduced as facility to prevent containment failure during severe accident. However, possibility of hydrogen risk has been issued due to inflow of hydrogen, condensation and removal of steam and complicated inner structure in CFVS. Preferentially benchmark work for THAI HM-2 experiment of OECD was decided to validate the methodology before detailed assessment of hydrogen risk in CFVS. The objectives of THAI HM-2 experiment were evaluation of hydrogen behavior, verification of numerical analysis tools and so on. In this paper, therefore, MELCOR simulation was carried out in comparison with the experiment results. Additionally, steam condensation effect was considered for detailed simulation. Hydrogen concentration from MELCOR results was underestimated in comparison to the experimental results.

Low cycle fatigue behavior of titanium carbide coated molybdenum

International Nuclear Information System (INIS)

Nishi, Hiroshi; Oku, Tatsuo; Kodaira, Tsuneo; Kikuyama, Toshihiko

1985-09-01

Sintered molybdenum coated by TiC is used for the first wall such as a troidal fixed limiter and a magnetic limiter plate in JT-60, that is being operated at JAERI presently. This report describes the low cycle fatigue behavior of sintered molybdenum and the influence of TiC coating on fatigue strength. The low cycle fatigue test was conducted at room temperature and 500 0 C. The test results was also analyzed by fractographic observation, metallography and element analysis using EPMA. The low cycle fatigue strength of the molybdenum coated by TiC at 500 0 C is decreased compared with the one at room temperature. (author)

Developing suitable buffers to capture transport cycling behavior

DEFF Research Database (Denmark)

Madsen, Thomas; Schipperijn, Jasper; Christiansen, Lars Breum

2014-01-01

units (e.g., home-buffer-based neighborhoods) are not necessarily representative for environmental exposure. An increased understanding of appropriate neighborhoods is needed. GPS cycling tracks from 78 participants for 7 days form the basis for the development and testing of different neighborhood...... buffers for transport cycling. The percentage of GPS points per square meter was used as indicator of the effectiveness of a series of different buffer types, including home-based network buffers, shortest route to city center buffers, and city center-directed ellipse-shaped buffers. The results show...... center-directed ellipse-shaped buffers yielded better results than traditional home-based network buffer types. The ellipse-shaped buffer types could therefore be considered an alternative to more traditional buffers or administrative units in future studies of transport cycling behavior....

Hydrogen production processes; Procedes de production d'hydrogene

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-07-01

The goals of this first Gedepeon workshop on hydrogen production processes are: to stimulate the information exchange about research programs and research advances in the domain of hydrogen production processes, to indicate the domains of interest of these processes and the potentialities linked with the coupling of a nuclear reactor, to establish the actions of common interest for the CEA, the CNRS, and eventually EDF, that can be funded in the framework of the Gedepeon research group. This document gathers the slides of the 17 presentations given at this workshop and dealing with: the H{sub 2} question and the international research programs (Lucchese P.); the CEA's research program (Lucchese P., Anzieu P.); processes based on the iodine/sulfur cycle: efficiency of a facility - flow-sheets, efficiencies, hard points (Borgard J.M.), R and D about the I/S cycle: Bunsen reaction (Colette S.), R and D about the I/S cycle: the HI/I{sub 2}/H{sub 2}O system (Doizi D.), demonstration loop/chemical engineering (Duhamet J.), materials and corrosion (Terlain A.); other processes under study: the Westinghouse cycle (Eysseric C.), other processes under study at the CEA (UT3, plasma,...) (Lemort F.), database about thermochemical cycles (Abanades S.), Zn/ZnO cycle (Broust F.), H{sub 2} production by cracking, high temperature reforming with carbon trapping (Flamant G.), membrane technology (De Lamare J.); high-temperature electrolysis: SOFC used as electrolyzers (Grastien R.); generic aspects linked with hydrogen production: technical-economical evaluation of processes (Werkoff F.), thermodynamic tools (Neveu P.), the reactor-process coupling (Aujollet P.). (J.S.)

Efficiency of the sulfur–iodine thermochemical water splitting process for hydrogen production based on ADS (accelerator driven system)

International Nuclear Information System (INIS)

García, Lázaro; González, Daniel; García, Carlos; García, Laura; Brayner, Carlos

2013-01-01

The current hydrogen production is based on fossil fuels; they have a huge contribution to the atmosphere's pollution. Thermochemical water splitting cycles don't present this issue because the required process heat is obtained from nuclear energy and therefore, the environmental impact is smaller than using conventional fuels. Although, solar hydrogen production could be also used for practical applications because it's lower environmental impact. One of the promising approaches to produce large quantities of hydrogen in an efficient way using nuclear energy is the sulfur–iodine (S–I) thermochemical water splitting cycle. The nuclear source proposed in this paper is a pebble bed gas cooled transmutation facility. Pebble bed very high temperature advanced systems have great perspectives to assume the future nuclear energy. Softwares based on CPS (chemical process simulation) can be used to simulate the thermochemical water splitting sulfur-iodine cycle for hydrogen production. In this paper, a model for analyzing the sulfur-iodine process sensibility respect to the thermodynamics parameters: temperature, pressure and mass flow is developed. Efficiency is also calculated and the influence of different parameters on this value. The behavior of the proposed model for different values of initial reactant's flow, is analyzed. - Highlights: • Chemical Process Simulation (CPS) of the complete sulfur iodine cycle. • Conceptual design of an accelerator driven system for hydrogen production. • Radial and axial temperature profile for the end of stationary cycle (EOC). • Thermal stability of the sulfuric and hydriodic acid sections determination. • Sulfur iodine cycle efficiency analyses for different heat flow from the ADS

Achievement report for 1st phase (fiscal 1974-80) Sunshine Program research and development - Hydrogen energy. Research on hydrogen production technology using thermochemical process (Research on cycles of Fe systems etc.); 1974-1980 nendo suiso energy seika hokokusho. Netsu kagakuho ni yoru suiso seizo gijutsu no kenkyu (tetsukei cycle nado no kenkyu)

Energy Technology Data Exchange (ETDEWEB)

NONE

1981-03-01

Collected in this report are the results of efforts of the Government Industrial Research Institute, Osaka, in the 7-year period that began in fiscal 1974. The Institute, after looking for basic reactions in thermochemical cycles which are promising, has come to propose a new cycle in which iron and bromine are the reactants. In the research, the Fe-Br reaction is divided into a hydrogen generating loop and an oxygen generating loop, both to be developed into devices. Problems in developing them into a cycle are isolated, and solved. In the hydrogen generating loop, the use of a molten salt is contrived for the prevention of reduction in the reactivity of the Fe{sub 3}O{sub 4} to be generated, and now it is expected that the problem will be solved. No problem is detected in the oxygen generating loop. The process is now accepted as a superb one. As for the materials for the Fe-Br-based cycle apparatus, important tasks have to be undertaken since existing materials cannot be used as is. Besides, thermal efficiency etc. are estimated for a new As-Br-based hybrid cycle and the Fe-Br-based cycle. (NEDO)

Fatigue of vanadium--hydrogen alloys

International Nuclear Information System (INIS)

Lee, K.S.; Stoloff, N.S.

1975-01-01

Hydrogen contents near and above the room temperature solubility limit increase the high cycle fatigue life but decrease low cycle life of polycrystalline vanadium. Changes in endurance limit with hydrides may be a consequence of decreased cyclic strain hardening coefficient, n'. 132 ppM hydrogen in solution has only a slightly beneficial effect on stress controlled fatigue life and essentially no effect on low cycle fatigue life. Unalloyed vanadium exhibits profuse striations, while hydrides produce cleavage cracks in fatigued samples. 10 fig

Hydrogen storage behaviors of Ni-doped graphene Oxide/MIL-101 hybrid composites.

Science.gov (United States)

Lee, Seul-Yi; Park, Soo-Jin

2013-01-01

In this work, Ni-doped graphene oxide/MIL-101 hybrid composites (Ni--GO/MIL) were prepared to investigate their hydrogen storage behaviors. Ni--GO/MIL was synthesized by adding Ni--GO in situ during the synthesis of MIL-101 using a hydrothermal process, which was conducted by conventional convection heating with Cr(III) ion as a metal center and telephthalic acid as organic ligands. The crystalline structures and morphologies were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The specific surface area and micropore volume were investigated by N2/77 K adsorption isotherms using the Brunauer-Emmett-Teller (BET) method and Dubinin-Radushkevic (D-R) equation, respectively. The hydrogen storage capacity was investigated by BEL-HP at 77 K and 1 bar. The obtained results show that Ni--GO/MIL presents new directions for achieving novel hybrid materials with higher hydrogen storage capacity.

Precise calibration of few-cycle laser pulses with atomic hydrogen

Science.gov (United States)

Wallace, W. C.; Kielpinski, D.; Litvinyuk, I. V.; Sang, R. T.

2017-12-01

Interaction of atoms and molecules with strong electric fields is a fundamental process in many fields of research, particularly in the emerging field of attosecond science. Therefore, understanding the physics underpinning those interactions is of significant interest to the scientific community. One crucial step in this understanding is accurate knowledge of the few-cycle laser field driving the process. Atomic hydrogen (H), the simplest of all atomic species, plays a key role in benchmarking strong-field processes. Its wide-spread use as a testbed for theoretical calculations allows the comparison of approximate theoretical models against nearly-perfect numerical solutions of the three-dimensional time-dependent Schrödinger equation. Until recently, relatively little experimental data in atomic H was available for comparison to these models, and was due mostly due to the difficulty in the construction and use of atomic H sources. Here, we review our most recent experimental results from atomic H interaction with few-cycle laser pulses and how they have been used to calibrate important laser pulse parameters such as peak intensity and the carrier-envelope phase (CEP). Quantitative agreement between experimental data and theoretical predictions for atomic H has been obtained at the 10% uncertainty level, allowing for accurate laser calibration intensity at the 1% level. Using this calibration in atomic H, both accurate CEP data and an intensity calibration standard have been obtained Ar, Kr, and Xe; such gases are in common use for strong-field experiments. This calibration standard can be used by any laboratory using few-cycle pulses in the 1014 W cm-2 intensity regime centered at 800 nm wavelength to accurately calibrate their peak laser intensity to within few-percent precision.

LARGE-SCALE PRODUCTION OF HYDROGEN BY NUCLEAR ENERGY FOR THE HYDROGEN ECONOMY

International Nuclear Information System (INIS)

SCHULTZ, K.R.; BROWN, L.C.; BESENBRUCH, G.E.; HAMILTON, C.J.

2003-01-01

OAK B202 LARGE-SCALE PRODUCTION OF HYDROGEN BY NUCLEAR ENERGY FOR THE HYDROGEN ECONOMY. The ''Hydrogen Economy'' will reduce petroleum imports and greenhouse gas emissions. However, current commercial hydrogen production processes use fossil fuels and releases carbon dioxide. Hydrogen produced from nuclear energy could avoid these concerns. The authors have recently completed a three-year project for the US Department of Energy whose objective was to ''define an economically feasible concept for production of hydrogen, by nuclear means, using an advanced high-temperature nuclear reactor as the energy source''. Thermochemical water-splitting, a chemical process that accomplishes the decomposition of water into hydrogen and oxygen, met this objective. The goal of the first phase of this study was to evaluate thermochemical processes which offer the potential for efficient, cost-effective, large-scale production of hydrogen and to select one for further detailed consideration. The authors selected the Sulfur-Iodine cycle, In the second phase, they reviewed all the basic reactor types for suitability to provide the high temperature heat needed by the selected thermochemical water splitting cycle and chose the helium gas-cooled reactor. In the third phase they designed the chemical flowsheet for the thermochemical process and estimated the efficiency and cost of the process and the projected cost of producing hydrogen. These results are summarized in this paper

Experimental studies on optimal process of the iodine-sulfur cycle for nuclear hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Yoon, Ho Joon

2010-02-15

For nuclear hydrogen production, we selected Iodine-Sulfur (I-S) cycle as the most promising one by screening process among 115 thermo-chemical water splitting technologies. We developed a thermo-physical model for the hydrogen-iodide (HI) VLE and decomposition behavior in the iodine-sulfur (IS) cycle to improve the conventional I-S cycle suggested by GA. Neumann's modified NRTL model was improved by correcting an unphysical assumption for the non-randomness parameter, and using the two-step equilibrium approach for the HI decomposition modeling. However, the parameters of the model were decided through regression with the 271 sets of existing experimental data: the accuracy of the model should be improved by more experimental data over all operating ranges, especially, in the high temperature and high pressure regions. To obtain the data of those regions, an autoclave for high temperature and high pressure was designed and manufactured. Various materials and surface coating technologies were investigated for preventing corrosion from acids. However, we have currently failed to overcome the corrosion problems with highly corrosive acids at a high temperature and high pressure. We experimentally validated that azeotropic constraint between acid and H{sub 2}O undermined the total efficiency of the I-S cycle. As mentioned above, the conventional I-S cycle suffers from low thermal efficiency and highly corrosive streams. To alleviate these problems, we have proposed the optimal operating conditions for the Bunsen reaction and devised a new KAIST flowsheet that produces highly enriched HI through spontaneous L-L phase separation and simple flash processes under low pressure. A series of phase separation experiments were performed to validate the new flowsheet and extend its feasibility. When the molar ratio of I{sub 2}/H{sub 2}SO{sub 4} in the feed increased from 2 to 4, the molar ratio of HI/(HI+H{sub 2}O) in the HI{sub x} phase improved from 0.157 to 0.22, which

Experimental studies on optimal process of the iodine-sulfur cycle for nuclear hydrogen production

International Nuclear Information System (INIS)

Yoon, Ho Joon

2010-02-01

For nuclear hydrogen production, we selected Iodine-Sulfur (I-S) cycle as the most promising one by screening process among 115 thermo-chemical water splitting technologies. We developed a thermo-physical model for the hydrogen-iodide (HI) VLE and decomposition behavior in the iodine-sulfur (IS) cycle to improve the conventional I-S cycle suggested by GA. Neumann's modified NRTL model was improved by correcting an unphysical assumption for the non-randomness parameter, and using the two-step equilibrium approach for the HI decomposition modeling. However, the parameters of the model were decided through regression with the 271 sets of existing experimental data: the accuracy of the model should be improved by more experimental data over all operating ranges, especially, in the high temperature and high pressure regions. To obtain the data of those regions, an autoclave for high temperature and high pressure was designed and manufactured. Various materials and surface coating technologies were investigated for preventing corrosion from acids. However, we have currently failed to overcome the corrosion problems with highly corrosive acids at a high temperature and high pressure. We experimentally validated that azeotropic constraint between acid and H 2 O undermined the total efficiency of the I-S cycle. As mentioned above, the conventional I-S cycle suffers from low thermal efficiency and highly corrosive streams. To alleviate these problems, we have proposed the optimal operating conditions for the Bunsen reaction and devised a new KAIST flowsheet that produces highly enriched HI through spontaneous L-L phase separation and simple flash processes under low pressure. A series of phase separation experiments were performed to validate the new flowsheet and extend its feasibility. When the molar ratio of I 2 /H 2 SO 4 in the feed increased from 2 to 4, the molar ratio of HI/(HI+H 2 O) in the HI x phase improved from 0.157 to 0.22, which is high enough to generate

Hydrogen production by the iodine-sulphur thermochemical cycle. Total and partial pressure measurements

International Nuclear Information System (INIS)

D Doizi; V Dauvois; J L Roujou; V Delanne; P Fauvet; B Larousse; O Hercher; P Carles; C Moulin

2006-01-01

The iodine sulphur thermochemical cycle appears to be one of the most promising candidate for the massive production of hydrogen using nuclear energy. The key step in this cycle is the HI distillation section which must be optimized to get a good efficiency of the overall cycle. The concept of reactive versus extractive distillation of HI has been proposed because of its potentiality. The design and the optimization of the reactive distillation column requires the knowledge of the liquid vapour equilibrium over the ternary HI-I 2 -H 2 O mixtures up to 300 C and 100 bars. A general methodology based on three experimental devices imposed by the very corrosive and concentrated media will be described: 1) I1 for the total pressure measurement versus different ternary compositions. 2) I2 for the partial and total pressure measurements around 130 C and 2 bars to validate the choice of the analytical optical 'online' techniques we have proposed. 3) I3 for the partial and total pressures measurements in the process domain. The results obtained on pure samples, binary mixtures HI-H 2 O and ternary mixtures using an experimental design analysis in the experimental device I2 will be discussed. (authors)

Effects of molybdenum dithiocarbamate and zinc dialkyl dithiophosphate additives on tribological behaviors of hydrogenated diamond-like carbon coatings

International Nuclear Information System (INIS)

Yue, Wen; Liu, Chunyue; Fu, Zhiqiang; Wang, Chengbiao; Huang, Haipeng; Liu, Jiajun

2014-01-01

Highlights: • For MoDTC, DLC coating showed better anti-friction and worse anti-wear behaviors. • The improved anti-friction property was due to graphitization and MoS 2 . • Formation of MoO x resulted in a high wear volume. • For ZDDP, DLC coating showed the best anti-wear and the worst anti-friction behaviors. • Absence of friction reducing product and graphitized layer resulted in a higher friction. - Abstract: The tribological behaviors of hydrogenated diamond-like carbon (DLC) coatings under varied load conditions lubricated with polyalpha olefin (PAO), molybdenum dithiocarbamate (MoDTC) and zinc dialkyl dithiophosphate (ZDDP) additives were investigated in this paper. Hydrogenated DLC coatings were synthesized through the decomposition of acetylene by the ion source. The tribological performances were measured on a SRV tribometer. The morphologies and chemical structures of the DLC coatings were investigated by the scanning electron microscope (SEM), Raman spectrometer (Raman) and X-ray photoelectron spectroscope (XPS). It was shown that the low friction and high wear were achieved on the hydrogenated DLC coating under MoDTC lubrication, while low wear was found on the hydrogenated DLC coating lubricated by ZDDP. The primary reason was attributed to different tribofilms formed on the contact area and the formation of graphitic layer. Both factors working together leaded to quite different tribological behaviors

Effect of Thermal Cycling on the Tensile Behavior of CF/AL Fiber Metal Laminates

Directory of Open Access Journals (Sweden)

Muhammad Farhan Noor

2017-09-01

Full Text Available The objective of this research work was to estimate the effect of thermal cycling on the tensile behavior of CARALL composites. Fiber metal laminates (FMLs, based on 2D woven carbon fabric and 2024-T3 Alclad aluminum alloy sheet, was manufactured by pressure molding technique followed by hand layup method. Before fabrication, aluminum sheets were anodized with phosphoric acid to produce micro porous alumina layer on surface. This micro-porous layer is beneficial to produce strong bonding between metal and fiber surfaces in FMLs. The effect of thermal cycling (-65 to +70ºC on the tensile behavior of Cf/Al based FML was studied. Tensile strength was increased after 10 thermal cycles, but it was slightly decreased to some extent after 30, and 50 thermal cycles. Tensile modulus also shown the similar behavior as that of tensile strength.

Rate equations modeling for hydrogen inventory studies during a real tokamak material thermal cycle

Energy Technology Data Exchange (ETDEWEB)

Bonnin, X., E-mail: xavier.bonnin@iter.org [LSPM-CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue Jean-Baptiste Clément, F-93430 Villetaneuse (France); Hodille, E. [IRFM, CEA-Cadarache, F-13108 St-Paul-Lez-Durance (France); Ning, N. [LSPM-CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue Jean-Baptiste Clément, F-93430 Villetaneuse (France); Sang, C. [School of Physics and Optoelectronics Technology, Dalian University of Technology, Dalian 116024 (China); Grisolia, Ch. [IRFM, CEA-Cadarache, F-13108 St-Paul-Lez-Durance (France)

2015-08-15

Prediction and control of tritium inventory in plasma-facing components (PFCs) is a critical nuclear safety issue for ITER and future fusion devices. This goal can be achieved through rate equations models as presented here. We calibrate our models with thermal desorption spectrometry results to obtain a validated set of material parameters relevant to hydrogen inventory processes in bulk tungsten. The best fits are obtained with two intrinsic trap types, deep and shallow, and an extrinsic trap created by plasma irradiation and plastic deformation of the tungsten matrix associated with blister formation. We then consider a realistic cycle of plasma discharges consisting of 400 s of plasma exposure followed by a resting period of 1000 s, repeating for several hours. This cycle is then closed by a long “overnight” period, thus providing an estimate of the amount of tritium retained in the PFCs after a full day of standard operation.

Mitigation of climate change via a copper-chlorine hybrid thermochemical water splitting cycle for hydrogen production from nuclear energy

International Nuclear Information System (INIS)

Orhan, M.F.; Dincer, I.; Rosen, M.A.

2009-01-01

Concerns regarding climate change have motivated research on clean energy resources. While many energy resources have limitations, nuclear energy has the potential to supply a significant share of energy supply without contributing to climate change. Nuclear energy has been used mainly for electric power generation, but hydrogen production via thermochemical water decomposition provides another option for the utilization of nuclear thermal energy. This paper describes nuclear-based hydrogen production technologies and discusses the role of the Cu-Cl cycle for thermochemical water decomposition, potentially driven in part by waste heat from a nuclear generating station, in reducing greenhouse gas emissions. (author)

In-situ investigation of hydrogen evolution behavior in vanadium redox flow batteries

International Nuclear Information System (INIS)

Wei, L.; Zhao, T.S.; Xu, Q.; Zhou, X.L.; Zhang, Z.H.

2017-01-01

Highlights: • An in-situ method to investigate hydrogen evolution in VRFBs is developed. • The rate of hydrogen evolution during battery operation is quantified. • The gas evolution behaviors in the charge process of VRFBs are observed. - Abstract: In this work, we conceived and fabricated a three-electrode electrochemical cell and transparent vanadium redox flow battery to in-situ investigate the hydrogen evolution reaction during battery operation. Experimental results show that operating temperature has a strong influence on the HER rate. In particular, compared with V"3"+ reduction reaction, HER is more sensitive to temperature variation. It is also found that, contrary to the conventional wisdom that side reactions occur at the late stage of the charge process, H_2 evolves at a relatively low SOC. About 0.26 and 1.94 mL H_2 were collected at an early (SOC lower than 20%) and end of the charge process, respectively, suggesting that attention to the hydrogen formation at the negative electrode in the early charge process should also be paid to during long-term battery operations. Moreover, the produced hydrogen gas at the negative side prefers to form macroscopically observable bubbles onto the electrode surface, covering the active sites for vanadium redox reactions, while oxygen evolution (including CO_2 production) at the positive side corrodes electrode surface and introduces certain oxygen-containing functional groups.

Heat Balance Study on Integrated Cycles for Hydrogen and Electricity Generation in VHTR - Part 2 -

International Nuclear Information System (INIS)

Lee, Sang Il; Yoo, Yeon Jae; Heo, Gyunyoung; Park, Soyoung; Kang, Yeon Kwan

2015-01-01

In the paper, reverse engineering was performed on SCMHR proposed by NGNP to reconstruct it into PEPSE. This model was used to analyze sensitivity of key variables. The paper also presented a concept design of thermal cycle, where heat of nuclear reactor is partially used for hydrogen production and remaining heat is used to generate power through IHX. This study introduces the results of concept designs on thermal cycle constructed using methods that are somewhat different from the previous results. As for the first method, efficiency under main steam condition proposed by NGNP was analyzed using ultra supercritical steam cycle, which exhibits highest efficiency among commercial technologies available. Another method was to prepare heat balance using supercritical CO 2 cycle, which has recently been commercialized in small scale and is undergoing R and D efforts for scale-up. As a part of concept design for high temperature gas reactor, this paper attempts different types of electricity generation cycle design and compares their advantages and disadvantages. A reference model was developed to change original design of NGNP. Sensitivity analysis can be performed according to changing performance of facility and external conditions. A Rankine cycle model operated under SC or USC condition was created by adding to a previous study to carry out key sensitivity analysis. Data for future design will be prepared through supplementary study, and the ultimate objective is to make contribution to optimal design of high temperature gas reactor

Heat Balance Study on Integrated Cycles for Hydrogen and Electricity Generation in VHTR - Part 2 -

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Il; Yoo, Yeon Jae [Hyundai Engineering Company Ltd., Seouul (Korea, Republic of); Heo, Gyunyoung; Park, Soyoung; Kang, Yeon Kwan [Kyung Hee University, Yongin (Korea, Republic of)

2015-10-15

In the paper, reverse engineering was performed on SCMHR proposed by NGNP to reconstruct it into PEPSE. This model was used to analyze sensitivity of key variables. The paper also presented a concept design of thermal cycle, where heat of nuclear reactor is partially used for hydrogen production and remaining heat is used to generate power through IHX. This study introduces the results of concept designs on thermal cycle constructed using methods that are somewhat different from the previous results. As for the first method, efficiency under main steam condition proposed by NGNP was analyzed using ultra supercritical steam cycle, which exhibits highest efficiency among commercial technologies available. Another method was to prepare heat balance using supercritical CO{sub 2} cycle, which has recently been commercialized in small scale and is undergoing R and D efforts for scale-up. As a part of concept design for high temperature gas reactor, this paper attempts different types of electricity generation cycle design and compares their advantages and disadvantages. A reference model was developed to change original design of NGNP. Sensitivity analysis can be performed according to changing performance of facility and external conditions. A Rankine cycle model operated under SC or USC condition was created by adding to a previous study to carry out key sensitivity analysis. Data for future design will be prepared through supplementary study, and the ultimate objective is to make contribution to optimal design of high temperature gas reactor.

A general survey of the potential and the main issues associated with the sulfur-iodine thermochemical cycle for hydrogen production using nuclear heat

International Nuclear Information System (INIS)

Vitart, Xavier; Carles, Philippe; Anzieu, Pascal

2008-01-01

The thermochemical sulfur-iodine cycle is studied by CEA with the objective of massive hydrogen production using nuclear heat at high temperature. The challenge is to acquire by the end of 2008 the necessary decision elements, based on a scientific and validated approach, to choose the most promising way to produce hydrogen using a generation IV nuclear reactor. Amongst the thermochemical cycles, the sulfur-iodine process remains a very promising solution in matter of efficiency and cost, versus its main competitor, conventional electrolysis. The sulfur-iodine cycle is a very versatile process, which allows lot of variants for each section which can be adjusted in synergy in order to optimise the whole process. The main part of CEA's program is devoted to the study of the basic processes: new thermodynamics data acquisition, optimisation of water and iodine quantity, optimisation of temperature and pressure in each unit of the flow-sheet and survey of innovative solutions (membrane separations for instance). This program also includes optimisation of a detailed flow-sheet and studies for a hydrogen production plant (design, scale, first evaluations of safety issues and technico-economic questions). This program interacts strongly with other teams, in the framework of international collaborations (Europe, USA for instance). (author)

A general survey of the potential and the main issues associated with the sulfur-iodine thermochemical cycle for hydrogen production using nuclear heat

International Nuclear Information System (INIS)

Vitart, X.; Carles, P.; Anzieu, P.

2008-01-01

The thermochemical sulfur-iodine cycle is studied by CEA with the objective of massive hydrogen production using nuclear heat at high temperature. The challenge is to acquire by the end of 2008 the necessary decision elements, based on a scientific and validated approach, to choose the most promising way to produce hydrogen using a generation IV nuclear reactor. Amongst the thermochemical cycles, the sulfur-iodine process remains a very promising solution in matter of efficiency and cost, versus its main competitor, conventional electrolysis. The sulfur-iodine cycle is a very versatile process, which allows lot of variants for each section which can be adjusted in synergy in order to optimise the whole process. The main part of CEA's program is devoted to the study of the basic processes: new thermodynamics data acquisition, optimisation of water and iodine quantity, optimisation of temperature and pressure in each unit of the flow-sheet and survey of innovative solutions (membrane separations for instance). This program also includes optimisation of a detailed flow-sheet and studies for a hydrogen production plant (design, scale, first evaluations of safety issues and technico-economic questions). This program interacts strongly with other teams, in the framework of international collaborations (Europe, USA for instance). (authors)

Characterization of hydrogenation behavior on Mo-modified Zr-Nb alloys as nuclear fuel cladding materials

International Nuclear Information System (INIS)

Yang, H.L.; Shibukawa, S.; Abe, H.; Satoh, Y.; Matsukawa, Y.; Kido, T.

2014-01-01

The effects of Mo in Zr-Nb alloys are investigated in terms of their mechanical properties associated with microstructure, as well as their behavior under hydrogen environment. Zr-Nb-Mo alloys were fabricated by arc melting and subsequently cold rolling and annealing below the eutectoid temperature. Hydrogen was absorbed in a furnace under argon and hydrogen gas flow environment at high temperature. X-Ray diffraction, electron backscatter diffraction, and tensile test were jointly utilized to carry out detailed microstructural characterization and mechanical properties. Results showed that fcc-δ-ZrH 1.66 was formed in all hydrogen-absorbed alloys, and the amount of hydride enhanced with increasing of hydrogen content. In addition, it was clear that δ-ZrH 1.66 was precipitated both in grain boundary and interior, and preferential precipitation was observed on the habit planes of (0001) and {101-bar7}. Moreover, the strengthening effect by Mo addition was observed. The ductility loss by hydrogen absorption was found from fracture surface observation. Large area cleavage facets were found in Mo-free specimen, and less cleavage facets was observed in Mo-containing specimen, showing an appropriate addition of Mo can increase the tolerance to hydrogen embrittlement. (author)

Renewable hydrogen production via thermochemical/electrochemical coupling

Energy Technology Data Exchange (ETDEWEB)

Ambrosini, Andrea [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Babiniec, Sean Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Miller, James E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-10-01

A coupled electrochemical/thermochemical cycle was investigated to produce hydrogen from renewable resources. Like a conventional thermochemical cycle, this cycle leverages chemical energy stored in a thermochemical working material that is reduced thermally by solar energy. However, in this concept, the stored chemical energy only needs to be partially, but not fully, capable of splitting steam to produce hydrogen. To complete the process, a proton-conducting membrane is driven to separate hydrogen as it is produced, thus shifting the thermodynamics toward further hydrogen production. This novel coupled-cycle concept provides several benefits. First, the required oxidation enthalpy of the reversible thermochemical material is reduced, enabling the process to occur at lower temperatures. Second, removing the requirement for spontaneous steam-splitting widens the scope of materials compositions, allowing for less expensive/more abundant elements to be used. Lastly, thermodynamics calculations suggest that this concept can potentially reach higher efficiencies than photovoltaic-to-electrolysis hydrogen production methods. This Exploratory Express LDRD involved assessing the practical feasibility of the proposed coupled cycle. A test stand was designed and constructed and proton-conducting membranes were synthesized. While the full proof of concept was not achieved, the individual components of the experiment were validated and new capabilities that can be leveraged by a variety of programs were developed.

Greenhouse gas implications of using coal for transportation: Life cycle assessment of coal-to-liquids, plug-in hybrids, and hydrogen pathways

International Nuclear Information System (INIS)

Jaramillo, Paulina; Samaras, Constantine; Wakeley, Heather; Meisterling, Kyle

2009-01-01

Using coal to produce transportation fuels could improve the energy security of the United States by replacing some of the demand for imported petroleum. Because of concerns regarding climate change and the high greenhouse gas (GHG) emissions associated with conventional coal use, policies to encourage pathways that utilize coal for transportation should seek to reduce GHGs compared to petroleum fuels. This paper compares the GHG emissions of coal-to-liquid (CTL) fuels to the emissions of plug-in hybrid electric vehicles (PHEV) powered with coal-based electricity, and to the emissions of a fuel cell vehicle (FCV) that uses coal-based hydrogen. A life cycle approach is used to account for fuel cycle and use-phase emissions, as well as vehicle cycle and battery manufacturing emissions. This analysis allows policymakers to better identify benefits or disadvantages of an energy future that includes coal as a transportation fuel. We find that PHEVs could reduce vehicle life cycle GHG emissions by up to about one-half when coal with carbon capture and sequestration is used to generate the electricity used by the vehicles. On the other hand, CTL fuels and coal-based hydrogen would likely lead to significantly increased emissions compared to PHEVs and conventional vehicles using petroleum-based fuels.

Toxoplasma gondii influences aversive behaviors of female rats in an estrus cycle dependent manner.

Science.gov (United States)

Golcu, Doruk; Gebre, Rahiwa Z; Sapolsky, Robert M

2014-08-01

The protozoan Toxoplasma gondii (T. gondii) manipulates the behavior of its rodent intermediate host to facilitate its passage to its feline definitive host. This is accomplished by a reduction of the aversive response that rodents show towards cat odors, which likely increases the predation risk. Females on average show similar changes as males. However, behaviors that relate to aversion and attraction are usually strongly influenced by the estrus cycle. In this study, we replicated behavioral effects of T. gondii in female rats, as well as expanded it to two novel behavioral paradigms. We also characterized the role of the estrus cycle in the behavioral effects of T. gondii on female rats. Uninfected females preferred to spend more time in proximity to rabbit rather than bobcat urine, and in a dark chamber rather than a lit chamber. Infected females lost both of these preferences, and also spent more time investigating social novelty (foreign bedding in their environment). Taken together, these data suggest that infection makes females less risk averse and more exploratory. Furthermore, this effect was influenced by the estrus cycle. Uninfected rats preferred rabbit urine to bobcat urine throughout the cycle except at estrus and metestrus. In contrast, infected rats lost this preference at every stage of the cycle except estrus. Commensurate with the possibility that this was a hormone-dependent effect, infected rats had elevated levels of circulating progesterone, a known anxiolytic. Copyright © 2014 Elsevier Inc. All rights reserved.

Hydrogen production processes

International Nuclear Information System (INIS)

2003-01-01

The goals of this first Gedepeon workshop on hydrogen production processes are: to stimulate the information exchange about research programs and research advances in the domain of hydrogen production processes, to indicate the domains of interest of these processes and the potentialities linked with the coupling of a nuclear reactor, to establish the actions of common interest for the CEA, the CNRS, and eventually EDF, that can be funded in the framework of the Gedepeon research group. This document gathers the slides of the 17 presentations given at this workshop and dealing with: the H 2 question and the international research programs (Lucchese P.); the CEA's research program (Lucchese P., Anzieu P.); processes based on the iodine/sulfur cycle: efficiency of a facility - flow-sheets, efficiencies, hard points (Borgard J.M.), R and D about the I/S cycle: Bunsen reaction (Colette S.), R and D about the I/S cycle: the HI/I 2 /H 2 O system (Doizi D.), demonstration loop/chemical engineering (Duhamet J.), materials and corrosion (Terlain A.); other processes under study: the Westinghouse cycle (Eysseric C.), other processes under study at the CEA (UT3, plasma,...) (Lemort F.), database about thermochemical cycles (Abanades S.), Zn/ZnO cycle (Broust F.), H 2 production by cracking, high temperature reforming with carbon trapping (Flamant G.), membrane technology (De Lamare J.); high-temperature electrolysis: SOFC used as electrolyzers (Grastien R.); generic aspects linked with hydrogen production: technical-economical evaluation of processes (Werkoff F.), thermodynamic tools (Neveu P.), the reactor-process coupling (Aujollet P.). (J.S.)

Goal and Scope in Life Cycle Sustainability Analysis: The Case of Hydrogen Production from Biomass

Directory of Open Access Journals (Sweden)

Milena Stefanova

2014-08-01

Full Text Available The framework for life cycle sustainability analysis (LCSA developed within the project CALCAS (Co-ordination Action for innovation in Life-Cycle Analysis for Sustainability is introducing a truly integrated approach for sustainability studies. However, it needs to be further conceptually refined and to be made operational. In particular, one of the gaps still hindering the adoption of integrated analytic tools for sustainability studies is the lack of a clear link between the goal and scope definition and the modeling phase. This paper presents an approach to structure the goal and scope phase of LCSA so as to identify the relevant mechanisms to be further detailed and analyzed in the modeling phase. The approach is illustrated with an on-going study on a new technology for the production of high purity hydrogen from biomass, to be used in automotive fuel cells.

Boron-Based Hydrogen Storage: Ternary Borides and Beyond

Energy Technology Data Exchange (ETDEWEB)

Vajo, John J. [HRL Laboratories, LLC, Malibu, CA (United States)

2016-04-28

DOE continues to seek reversible solid-state hydrogen materials with hydrogen densities of ≥11 wt% and ≥80 g/L that can deliver hydrogen and be recharged at moderate temperatures (≤100 °C) and pressures (≤100 bar) enabling incorporation into hydrogen storage systems suitable for transportation applications. Boron-based hydrogen storage materials have the potential to meet the density requirements given boron’s low atomic weight, high chemical valance, and versatile chemistry. However, the rates of hydrogen exchange in boron-based compounds are thus far much too slow for practical applications. Although contributing to the high hydrogen densities, the high valance of boron also leads to slow rates of hydrogen exchange due to extensive boron-boron atom rearrangements during hydrogen cycling. This rearrangement often leads to multiple solid phases occurring over hydrogen release and recharge cycles. These phases must nucleate and react with each other across solid-solid phase boundaries leading to energy barriers that slow the rates of hydrogen exchange. This project sought to overcome the slow rates of hydrogen exchange in boron-based hydrogen storage materials by minimizing the number of solid phases and the boron atom rearrangement over a hydrogen release and recharge cycle. Two novel approaches were explored: 1) developing matched pairs of ternary borides and mixed-metal borohydrides that could exchange hydrogen with only one hydrogenated phase (the mixed-metal borohydride) and only one dehydrogenated phase (the ternary boride); and 2) developing boranes that could release hydrogen by being lithiated using lithium hydride with no boron-boron atom rearrangement.

Hydrogen Storage and Release Properties of Transition Metal-Added Magnesium Hydride Alloy Fabricated by Grinding in a Hydrogen Atmosphere

Energy Technology Data Exchange (ETDEWEB)

Kwon, Sung Nam; Song, Myoung Youp [Chonbuk National University, Jeonju (Korea, Republic of); Park, Hye Ryoung [Chonnam National University, Gwangju (Korea, Republic of)

2016-07-15

90 wt% MgH{sub 2}+5 wt% Ni+2.5 wt% Fe+2.5 wt% Ti (called MgH{sub 2}+Ni+Fe+Ti), a hydrogen storage and release material, was fabricated by grinding in a hydrogen atmosphere, and then its quantities of stored and released hydrogen as a function of time were examined. A nanocrystalline MgH{sub 2}+Ni+Fe+Ti specimen was made by grinding in a hydrogen atmosphere and subsequent hydrogen storage-release cycling. The crystallite size of Mg and the strain of the Mg crystallite after ten hydrogen storage-release cycles, which were obtained using the Williamson-Hall method, were 38.6 (±1.4) nm and 0.025 (±0.0081) %, respectively. The MgH{sub 2}+Ni+Fe+Ti sample after the process of grinding in a hydrogen atmosphere was highly reactive with hydrogen. The sample exhibited an available storage capacity of hydrogen (the amount of hydrogen stored during 60 minutes) of about 5.7 wt%. At the first cycle, the MgH2+Ni+Fe+Ti sample stored hydrogen of 5.53 wt% in 5 minutes, 5.66 wt% in 10 minutes and 5.73 wt% in 60 minutes at 573 K and 12 bar of hydrogen. The MgH{sub 2}+Ni+Fe+Ti after activation released hydrogen of 0.56 wt% in 5 minutes, 1.26 wt% in 10 minutes, 2.64 wt% in 20 minutes, 3.82 wt% in 30 minutes, and 5.03 wt% in 60 minutes.

Study on the combustion behavior of radiolytically generated hydrogen explosion in small scale annular vessels at the reprocessing plant

International Nuclear Information System (INIS)

Kudo, Tatsuya; Tamauchi, Yoshikazu; Arai, Nobuyuki; Dai, Wenbin; Sakaihara, Motohiro; Kanehira, Osamu

2017-01-01

Hydrogen is generated by radiolysis of water, etc. in process vessels in reprocessing plant. Usually, the hydrogen is scavenged by compressed air into vessels to prevent hydrogen explosion. When an earthquake beyond design based occurs, for example, the compressed air may stop and the hydrogen starts accumulating in the vessels, and under this condition, an ignition source might set off hydrogen explosion. Therefore, the explosion derived by the radiolytically generated hydrogen is designated as one of severe accidents on Rokkasho Reprocessing Plant in new regulatory requirements. It is important to understand the combustion behavior of hydrogen explosion inside a vessel for consideration of safety measures against the severe accident, because the influences of detonation are not considered in the design basis of vessels. Especially, the investigations about the combustion behavior which considered influence of interior obstacles inside the vessel are not performed yet. In order to investigate the combustion behavior comprehensively, explosion experiment, combustion analysis and structural analysis are carried out using the representative vessels (small scale annular vessel, small scale plate vessel, large scale annular vessel and large scale cylindrical vessel) selected from Rokkasho Reprocessing Plant. In this paper, the results of experiments and analysis of small scale annular vessel (as one of representative vessel, imitated a pulsed column in the reprocessing plant) are reported. As imitated vessels, three vessels are manufactured with different interior obstacle arrangements as follows, A) cylindrical obstacles are faithfully reproduced and are arranged based on the actual vessel, B) cylindrical obstacles are arranged more densely than the actual vessel, and C) there are no obstacles inside the vessel. Experiments of hydrogen explosion are performed under condition of stoichiometric hydrogen-air ratio (premixed hydrogen-air is used). As a result of

A study of hydrogen environment effects on microstructure property behavior of NASA-23 alloy and related alloy systems

International Nuclear Information System (INIS)

Diwan, R.M.

1990-01-01

The influence of hydrogen on the tensile properties and ductility behavior of NASA-23 alloy were analyzed. NASA-23 and other referenced alloys in cast and hipped conditions were solution treated and aged under selected conditions and characterized using optical metallography, scanning electron microscopy, and electron microprobe analysis techniques. The yield strength of NASA-23 is not affected much by hydrogen under tensile tests carried at 5000 psig conditions; however, the ultimate strength and ductility properties are degraded. This implies that the physical mechanisms operating would be related to the plastic deformation process. The fracture surfaces characteristics of NASA-23 specimens tensile tested in hydrogen, helium, and air were also analyzed. These revealed surface cracks around specimen periphery with the fracture surface showing a combination of intergranular and transgranular modes of fracture. It is seen that the specimens charged in hydrogen seem to favor a more brittle fracture mode in comparison to air and helium charged specimens. The AMCC casting characterization program is to be analyzed for their hydrogen behavior. As a result of this program, the basic microstructural factors and fracture characteristics in some cases were analyzed

Analysis of hydrogen content and distribution in hydrogen storage alloys using neutron radiography

International Nuclear Information System (INIS)

Sakaguchi, Hiroki; Hatakeyama, Keisuke; Satake, Yuichi; Esaka, Takao; Fujine, Shigenori; Yoneda, Kenji; Kanda, Keiji

2000-01-01

Small amounts of hydrogen in hydrogen storage alloys, such as Mg 2 Ni, were detected using neutron radiography (NRG). Hydrogen concentrations in a hydrogenated solid solution were determined by this technique. Furthermore, we were able to obtain NRG images for an initial stage of hydrogen absorption in the hydrogen storage alloys. NRG would be a new measurement method to clarify the behavior of hydrogen in hydrogen storage alloys. (author)

On the behavior of surface electromyographic variables during the menstrual cycle

International Nuclear Information System (INIS)

Soares, Fabiano Araujo; Salomoni, Sauro Emerick; De Carvalho, Joao Luiz Azevedo; Nascimento, Francisco Assis de Oliveira; Veneziano, Wilson Henrique; Pires, Kenia Fonseca; Da Rocha, Adson Ferreira

2011-01-01

The goal of this work is to study the behavior of electromyographic variables during the menstrual cycle. Ten female volunteers (24.0 ± 2.8 years of age) performed fatiguing isometric contractions, and electromyographic signals were measured on the biceps brachii in four phases of the menstrual cycle. Adaptations of classical algorithms were used for the estimation of the root mean square (RMS) value, absolute rectified value (ARV), mean frequency (MNF), median frequency (MDF), and conduction velocity (CV). The CV estimator had a higher (p = 0.002) rate of decrease at the end of the follicular phase and at the end of the luteal phase. The MDF (p = 0.002) and MNF (p = 0.004) estimators had a higher rate of decrease at the beginning of the follicular phase and at the end of the luteal phase. No significant differences between phases of the menstrual cycle were detected with the ARV and RMS estimators (p > 0.05). These results suggest that the behavior of the muscles in women presents different characteristics during different phases of the menstrual cycle. In particular, women were more susceptible to fatigue at the end of the luteal phase

ENERGY EFFICIENCY LIMITS FOR A RECUPERATIVE BAYONET SULFURIC ACID DECOMPOSITION REACTOR FOR SULFUR CYCLE THERMOCHEMICAL HYDROGEN PRODUCTION

Energy Technology Data Exchange (ETDEWEB)

Gorensek, M.; Edwards, T.

2009-06-11

A recuperative bayonet reactor design for the high-temperature sulfuric acid decomposition step in sulfur-based thermochemical hydrogen cycles was evaluated using pinch analysis in conjunction with statistical methods. The objective was to establish the minimum energy requirement. Taking hydrogen production via alkaline electrolysis with nuclear power as the benchmark, the acid decomposition step can consume no more than 450 kJ/mol SO{sub 2} for sulfur cycles to be competitive. The lowest value of the minimum heating target, 320.9 kJ/mol SO{sub 2}, was found at the highest pressure (90 bar) and peak process temperature (900 C) considered, and at a feed concentration of 42.5 mol% H{sub 2}SO{sub 4}. This should be low enough for a practical water-splitting process, even including the additional energy required to concentrate the acid feed. Lower temperatures consistently gave higher minimum heating targets. The lowest peak process temperature that could meet the 450-kJ/mol SO{sub 2} benchmark was 750 C. If the decomposition reactor were to be heated indirectly by an advanced gas-cooled reactor heat source (50 C temperature difference between primary and secondary coolants, 25 C minimum temperature difference between the secondary coolant and the process), then sulfur cycles using this concept could be competitive with alkaline electrolysis provided the primary heat source temperature is at least 825 C. The bayonet design will not be practical if the (primary heat source) reactor outlet temperature is below 825 C.

Enhanced Photoelectrochemical Behavior of H-TiO2 Nanorods Hydrogenated by Controlled and Local Rapid Thermal Annealing.

Science.gov (United States)

Wang, Xiaodan; Estradé, Sonia; Lin, Yuanjing; Yu, Feng; Lopez-Conesa, Lluis; Zhou, Hao; Gurram, Sanjeev Kumar; Peiró, Francesca; Fan, Zhiyong; Shen, Hao; Schaefer, Lothar; Braeuer, Guenter; Waag, Andreas

2017-12-01

Recently, colored H-doped TiO 2 (H-TiO 2 ) has demonstrated enhanced photoelectrochemical (PEC) performance due to its unique crystalline core-disordered shell nanostructures and consequent enhanced conduction behaviors between the core-shell homo-interfaces. Although various hydrogenation approaches to obtain H-TiO 2 have been developed, such as high temperature hydrogen furnace tube annealing, high pressure hydrogen annealing, hydrogen-plasma assisted reaction, aluminum reduction and electrochemical reduction etc., there is still a lack of a hydrogenation approach in a controlled manner where all processing parameters (temperature, time and hydrogen flux) were precisely controlled in order to improve the PEC performance of H-TiO 2 and understand the physical insight of enhanced PEC performance. Here, we report for the first time a controlled and local rapid thermal annealing (RTA) approach to prepare hydrogenated core-shell H-TiO 2 nanorods grown on F:SnO 2 (FTO) substrate in order to address the degradation issue of FTO in the typical TiO 2 nanorods/FTO system observed in the conventional non-RTA treated approaches. Without the FTO degradation in the RTA approach, we systematically studied the intrinsic relationship between the annealing temperature, structural, optical, and photoelectrochemical properties in order to understand the role of the disordered shell on the improved photoelectrochemical behavior of H-TiO 2 nanorods. Our investigation shows that the improvement of PEC performance could be attributed to (i) band gap narrowing from 3.0 to 2.9 eV; (ii) improved optical absorption in the visible range induced by the three-dimensional (3D) morphology and rough surface of the disordered shell; (iii) increased proper donor density; (iv) enhanced electron-hole separation and injection efficiency due to the formation of disordered shell after hydrogenation. The RTA approach developed here can be used as a suitable hydrogenation process for TiO 2 nanorods

Intentions to use bike-sharing for holiday cycling: An application of the Theory of Planned Behavior

DEFF Research Database (Denmark)

Kaplan, Sigal; Manca, Francesco; Nielsen, Thomas Alexander Sick

2014-01-01

This study explored the behavioral factors underlying tourist intentions to use urban bike-sharing for cycling while on holiday. The analytical framework relied on the Theory of Planned Behavior relating tourist intentions to favorable attitudes toward cycling, interest in bicycle technology...

Development of thermal-hydraulic safety codes for HTGRs with gas-turbine and hydrogen process cycles

International Nuclear Information System (INIS)

No, Hee Cheon; Yoon, Ho Joon; Lee, Byung Jin; Kim, Yong Soo; Jin, Hyeng Gon; Kim, Ji Hwan; Kim, Hyeun Min; Lim, Hong Sik

2008-01-01

We present three nuclear/hydrogen-related R and D activities being performed at KAIST: air-ingressed LOCA analysis code development, gas turbine analysis tool development, and hydrogen-production system analysis model development. The ICE numerical technique widely used for the safety analysis of water-reactors is successfully implemented into GAMMA in which we solve the basic equations for continuity, momentum conservation, energy conservation of the gas mixture, and mass conservation of 6 species (He, N2, O2, CO, CO2, and H2O). GAMMA has been extensively validated using data from 14 test facilities. We developed SANA code to predict the characteristics of HTGR helium turbines based on the throughflow calculation with a Newton-Raphson method that overcomes the weakness of the conventional method based on the successive iteration scheme. It is found out that the current method reaches stable and quick convergence even under the off-normal condition with the same degree of accuracy. The GAMMA-SANA coupled code was assessed by comparing its results with the steady-state of the GTHTR300, and the load reduction transient was simulated for the 100% to 70% power operation. The calculation results confirm that two-dimensional throughflow modeling can be successfully used to describe the gas turbine behavior. The dynamic equations for the distillation column of the HI process in the I-S cycle are described with 4 material components involved in the HI process: H2O, HI, I2, and H2. For the VLE prediction in the HI process we improved the Neumann model based on the NRTL (Non-Random Two-Liquid) model. Relative to the experimental data, the improved Neumann model shows deviations of 8.6% in maximum and 2.5% in average for the total pressure, and 9.5% in maximum for the liquid-liquid separation composition. Through a parametric analysis using the published experimental data related to the Bunsen reaction and liquid-liquid separation, an optimized operating condition for the

SCC growth behavior of stainless steel weld heat-affected zone in hydrogenated high temperature water

International Nuclear Information System (INIS)

Yamada, Takuyo; Terachi, Takumi; Miyamoto, Tomoki; Arioka, Koji

2010-01-01

It is known that the SCC growth rate of stainless steels in high-temperature water is accelerated by cold-work (CW). The weld heat-affected-zone (HAZ) of stainless steels is also deformed by weld shrinkage. However, only little have been reported on the SCC growth of weld HAZ of SUS316 and SUS304 in hydrogenated high-temperature water. Thus, in this present study, SCC growth experiments were performed using weld HAZ of stainless steels, especially to obtain data on the dependence of SCC growth on (1) temperature and (2) hardness in hydrogenated water at temperatures from 250degC to 340degC. And then, the SCC growth behaviors were compared between weld HAZ and CW stainless steels. The following results have been obtained. Significant SCC growth were observed in weld HAZ (SUS316 and SUS304) in hydrogenated water at 320degC. The SCC growth rates of the HAZ are similar to that of 10% CW non-sensitized SUS316, in accordance with that the hardness of weld HAZ is also similar to that of 10% CW SUS316. Temperature dependency of SCC growth of weld HAZ (SUS316 and SUS304) is also similar to that of 10% CW non-sensitized SUS316. That is, no significant SCC were observed in the weld HAZ (SUS316 and SUS304) in hydrogenated water at 340degC. This suggests that SCC growth behaviors of weld HAZ and CW stainless steels are similar and correlated with the hardness or yield strength of the materials, at least in non-sensitized regions. And the similar temperature dependence between the HAZ and CW stainless steels suggests that the SCC growth behaviors are also attributed to the common mechanism. (author)

Advances in hydrogen production by thermochemical water decomposition: A review

International Nuclear Information System (INIS)

Rosen, Marc A.

2010-01-01

Hydrogen demand as an energy currency is anticipated to rise significantly in the future, with the emergence of a hydrogen economy. Hydrogen production is a key component of a hydrogen economy. Several production processes are commercially available, while others are under development including thermochemical water decomposition, which has numerous advantages over other hydrogen production processes. Recent advances in hydrogen production by thermochemical water decomposition are reviewed here. Hydrogen production from non-fossil energy sources such as nuclear and solar is emphasized, as are efforts to lower the temperatures required in thermochemical cycles so as to expand the range of potential heat supplies. Limiting efficiencies are explained and the need to apply exergy analysis is illustrated. The copper-chlorine thermochemical cycle is considered as a case study. It is concluded that developments of improved processes for hydrogen production via thermochemical water decomposition are likely to continue, thermochemical hydrogen production using such non-fossil energy will likely become commercial, and improved efficiencies are expected to be obtained with advanced methodologies like exergy analysis. Although numerous advances have been made on sulphur-iodine cycles, the copper-chlorine cycle has significant potential due to its requirement for process heat at lower temperatures than most other thermochemical processes.

Magnesium for Hydrogen Storage

DEFF Research Database (Denmark)

Pedersen, Allan Schrøder; Kjøller, John; Larsen, B.

1983-01-01

A study of the hydrogenation characteristics of fine magnesium powder during repeated cycling has been performed using a high-pressure microbalance facility. No effect was found from the cycling regarding kinetics and storage capacity. The reaction rate of the absorption process was fast...... at temperatures around 600 K and above, but the reversed reaction showed somewhat slower kinetics around 600 K. At higher temperatures the opposite was found. The enthalpy and entropy change by the hydrogenation, derived from pressure-concentration isotherms, agree fairly well with those reported earlier....

A review of nickel hydrogen battery technology

Energy Technology Data Exchange (ETDEWEB)

Smithrick, J.J.; Odonnell, P.M.

1995-05-01

This paper on nickel hydrogen batteries is an overview of the various nickel hydrogen battery design options, technical accomplishments, validation test results and trends. There is more than one nickel hydrogen battery design, each having its advantage for specific applications. The major battery designs are individual pressure vessel (IPV), common pressure vessel (CPV), bipolar and low pressure metal hydride. State-of-the-art (SOA) nickel hydrogen batteries are replacing nickel cadmium batteries in almost all geosynchronous orbit (GEO) applications requiring power above 1 kW. However, for the more severe low earth orbit (LEO) applications (greater than 30,000 cycles), the current cycle life of 4000 to 10,000 cycles at 60 percent DOD should be improved. A NASA Lewis Research Center innovative advanced design IPV nickel hydrogen cell led to a breakthrough in cycle life enabling LEO applications at deep depths of discharge (DOD). A trend for some future satellites is to increase the power level to greater than 6 kW. Another trend is to decrease the power to less than 1 kW for small low cost satellites. Hence, the challenge is to reduce battery mass, volume and cost. A key is to develop a light weight nickel electrode and alternate battery designs. A common pressure vessel (CPV) nickel hydrogen battery is emerging as a viable alternative to the IPV design. It has the advantage of reduced mass, volume and manufacturing costs. A 10 Ah CPV battery has successfully provided power on the relatively short lived Clementine Spacecraft. A bipolar nickel hydrogen battery design has been demonstrated (15,000 LEO cycles, 40 percent DOD). The advantage is also a significant reduction in volume, a modest reduction in mass, and like most bipolar designs, features a high pulse power capability. A low pressure aerospace nickel metal hydride battery cell has been developed and is on the market.

Analysis of sulfur-iodine thermochemical cycle for solar hydrogen production. Part 1: decomposition of sulfuric acid

Energy Technology Data Exchange (ETDEWEB)

Huang, Cunping; T-Raissi, Ali [Central Florida Univ., Florida Solar Energy Center, Cocoa, FL (United States)

2005-05-01

The sulfur-iodine (S-I) thermochemical water splitting cycle is one of the most studied cycles for hydrogen (H{sub 2}) production. S-I cycle consists of four sections: (I) acid production and separation and oxygen purification, (II) sulfuric acid concentration and decomposition, (III) hydroiodic acid (HI) concentration, and (IV) HI decomposition and H{sub 2} purification. Section II of the cycle is an endothermic reaction driven by the heat input from a high temperature source. Analysis of the S-I cycle in the past thirty years have been focused mostly on the utilization of nuclear power as the high temperature heat source for the sulfuric acid decomposition step. Thermodynamic as well as kinetic considerations indicate that both the extent and rate of sulfuric acid decomposition can be improved at very high temperatures (in excess of 1000 deg C) available only from solar concentrators. The beneficial effect of high temperature solar heat for decomposition of sulfuric acid in the S-I cycle is described in this paper. We used Aspen Technologies' HYSYS chemical process simulator (CPS) to develop flowsheets for sulfuric acid (H{sub 2}SO{sub 4}) decomposition that include all mass and heat balances. Based on the HYSYS analyses, two new process flowsheets were developed. These new sulfuric acid decomposition processes are simpler and more stable than previous processes and yield higher conversion efficiencies for the sulfuric acid decomposition and sulfur dioxide and oxygen formation. (Author)

Carbon compound used in hydrogen storage

International Nuclear Information System (INIS)

Iturbe G, J.L.; Lopez M, B.E.

2004-01-01

In the present work it is studied the activated carbon of mineral origin for the sorption of hydrogen. The carbon decreased of particle size by means of the one alloyed mechanical. The time of mill was of 10 hours. The characterization one carries out by scanning electron microscopy and X-ray diffraction. The hydrogen sipped in the carbon material it was determined using the Thermal gravimetric method (TGA). The conditions of hydrogenation went at 10 atm of pressure and ambient temperature during 18 hours. They were also carried out absorption/desorption cycles of hydrogen in the same one system of thermal gravimetric analysis. The results showed percentages of sorption of 2% approximately in the cycles carried out in the system TGA and of 4.5% in weight of hydrogen at pressure of 10 atmospheres and ambient temperature during 18 hours. (Author)

What Inventory Behavior Tells Us about Business Cycles

OpenAIRE

James A. Kahn; Mark Bils

2000-01-01

Manufacturers' finished goods inventories move less than shipments over the business cycle. We argue that this requires marginal cost to be more procyclical than is conventionally measured. We construct, for six manufacturing industries, alternative measures of marginal cost that attribute high-frequency productivity shocks to procyclical work effort, and find that they are much more successful in accounting for inventory behavior. The difference is attributable to cyclicality in the shadow p...

Hydrogen and acetate cycling in two sulfate-reducing sediments: Buzzards Bay and Town Cove, Massachusetts

Energy Technology Data Exchange (ETDEWEB)

Novelli, P.C. (SUNY, Stony Brook, NY (USA) Univ. of Colorado, Boulder (USA)); Michelson, A.R.; Scranton, M.I. (SUNY, Stony Brook, NY (USA)); Banta, G.T.; Hobbie, J.E. (Marine Biological Laboratory, Woods, Hole, MA (USA)); Howarth, R.W. (Cornell Univ., Ithaca, NY (USA))

1988-10-01

Molecular hydrogen and acetate are believed to be key intermediates in the anaerobic remineralization of organic carbon. The authors have made measurements of the cycling of both these compounds in two marine sediments: the bioturbated sediments of Buzzards Bay, Mass., and the much more reducing sediments of Town Cove, Orleans, Mass. Hydrogen concentrations are similar in these environments (from less than 5 to 30 nM), and are within the range previously reported for coastal sediments. However, apparent hydrogen production rates differ by a factor of 60 between these two sediments and at both sites show strong correlation with measured rates of sulfate reduction. Acetate concentrations generally increased with depth in both environments; this increase was greater in Buzzards Bay (22.5 to 71.5 {mu}M) than in Town Cove (26 to 44 {mu}M). Acetate oxidation rates calculated from measured concentrations and {sup 14}C-acetate consumption rate constants suggest that the measured acetate was not all available to sulfate-reducing bacteria. Using the measured sulfate reduction rates, they estimate that between 2% and 100% of the measured acetate pool is biologically available, and that the bioavailable pool decreases with depth. A diagenetic model of the total acetate concentration suggests that consumption may be first order with respect to only a fraction of the total pool.

High-Performance Hydrogen Storage Nanoparticles Inside Hierarchical Porous Carbon Nanofibers with Stable Cycling.

Science.gov (United States)

Xia, Guanglin; Chen, Xiaowei; Zhao, Yan; Li, Xingguo; Guo, Zaiping; Jensen, Craig M; Gu, Qinfen; Yu, Xuebin

2017-05-10

An effective route based on space-confined chemical reaction to synthesize uniform Li 2 Mg(NH) 2 nanoparticles is reported. The hierarchical pores inside the one-dimensional carbon nanofibers (CNFs), induced by the creation of well-dispersed Li 3 N, serve as intelligent nanoreactors for the reaction of Li 3 N with Mg-containing precursors, resulting in the formation of uniformly discrete Li 2 Mg(NH) 2 nanoparticles. The nanostructured Li 2 Mg(NH) 2 particles inside the CNFs are capable of complete hydrogenation and dehydrogenation at a temperature as low as 105 °C with the suppression of ammonia release. Furthermore, by virtue of the nanosize effects and space-confinement by the porous carbon scaffold, no degradation was observed after 50 de/rehydrogenation cycles at a temperature as low as 130 °C for the as-prepared Li 2 Mg(NH) 2 nanoparticles, indicating excellent reversibility. Moreover, the theoretical calculations demonstrate that the reduction in particle size could significantly enhance the H 2 sorption of Li 2 Mg(NH) 2 by decreasing the relative activation energy barrier, which agrees well with our experimental results. This method could represent an effective, general strategy for synthesizing nanoparticles of complex hydrides with stable reversibility and excellent hydrogen storage performance.

The Hydrogen Pickup Behavior for Zirconium-based Alloys in Various Out-of-pile Corrosion Test Conditions

Energy Technology Data Exchange (ETDEWEB)

Aomi, M.; Etoh, Y.; Ishimoto, S.; Une, K. [Nippon Nuclear Fuel Development, Co., Ltd., 2163 Narita-cho, Oarai-machi, Ibaraki-ken, 311-1313 (Japan); Ito, K. [Global Nuclear Fuel Japan Co., Ltd., 3-1 Uchikawa 2-chome, Yokosuka-shi, Kanagawa-ken, 239-0836 (Japan)

2009-06-15

An acceleration of hydrogen absorption in zirconium alloy claddings at high burnups is one of the most important issues limiting the fuel performance from the viewpoint of cladding integrity. In this context, advanced cladding materials with higher corrosion resistant and lower hydrogen absorption properties have been widely searched in various organizations. In this study, four kinds of zirconium-based alloys, whose in-pile data had been acquired [1,2] were subjected to comprehensive out-of-pile corrosion tests with various temperature and atmosphere conditions in order to investigate the correlation between in-pile and out-of-pile corrosion and hydrogen pick-up behavior, i.e. Zry-2, GNF-Ziron (Zry-2-based alloy with {approx}0.25 wt % of Fe), Hi-FeNi Zircaloy (Zry-2-based alloy with {approx}0.25 wt % of Fe and {approx}0.1 wt% Ni), and VB (Zr-based alloy containing Sn, Cr, and {approx}0.5 wt % of Fe). All the alloys were annealed in RXA condition. The out-of-pile corrosion tests were carried out in three different conditions of 400 deg. C steam, 475 deg. C supercritical water, and 290 deg. C LiOH aqueous solution. In addition to these alloys, several Zry-2-based alloys with various iron contents were tested in 290 deg. C LiOH aqueous solution. Among the four corrosion conditions, the 290 deg. C LiOH aqueous solution test well screened the hydrogen pick-up behavior of the alloys. The hydrogen absorption decreased with higher iron contents in the alloys in both the out-of-pile and in-pile conditions. Especially, the distinct suppression of hydrogen absorption was observed for VB with the highest iron content. The similar dependence of iron content on the hydrogen pick-up fraction was also obtained for the Zry-2-based alloys with different iron contents, which were corroded in the 290 deg. C LiOH aqueous solution condition. As for the corrosion behavior in the 290 deg. C LiOH aqueous solution condition, the weight gains of Zry-2, GNF-Ziron and VB followed the 1

Influence of surface treatments on micropore structure and hydrogen adsorption behavior of nanoporous carbons.

Science.gov (United States)

Kim, Byung-Joo; Park, Soo-Jin

2007-07-15

The scope of this work was to control the pore sizes of porous carbons by various surface treatments and to investigate the relation between pore structures and hydrogen adsorption capacity. The effects of various surface treatments (i.e., gas-phase ozone, anodic oxidation, fluorination, and oxygen plasma) on the micropore structures of porous carbons were investigated by N(2)/77 K isothermal adsorption. The hydrogen adsorption capacity was measured by H(2) isothermal adsorption at 77 K. In the result, the specific surface area and micropore volume of all of the treated samples were slightly decreased due to the micropore filling or pore collapsing behaviors. It was also found that in F(2)-treated carbons the center of the pore size distribution was shifted to left side, meaning that the average size of the micropores decreased. The F(2)- and plasma-treated samples showed higher hydrogen storage capacities than did the other samples, the F(2)-treated one being the best, indicating that the micropore size of the porous carbons played a key role in the hydrogen adsorption at 77 K.

A study of hydrogen environment effects on microstructure property behavior of NASA-23 alloy and related alloy systems

Science.gov (United States)

Diwan, Ravinder M.

1990-01-01

This work is part of the overall advanced main combustion chamber (AMCC) casting characterization program of the Materials and Processes Laboratory of the Marshall Space Flight Center. The influence of hydrogen on the tensile properties and ductility behavior of NASA-23 alloy were analyzed. NASA-23 and other referenced alloys in cast and hipped conditions were solution treated and aged under selected conditions and characterized using optical metallography, scanning electron microscopy, and electron microprobe analysis techniques. The yield strength of NASA-23 is not affected much by hydrogen under tensile tests carried at 5000 psig conditions; however, the ultimate strength and ductility properties are degraded. This implies that the physical mechanisms operating would be related to the plastic deformation process. The fracture surfaces characteristics of NASA-23 specimens tensile tested in hydrogen, helium, and air were also analyzed. These revealed surface cracks around specimen periphery with the fracture surface showing a combination of intergranular and transgranular modes of fracture. It is seen that the specimens charged in hydrogen seem to favor a more brittle fracture mode in comparison to air and helium charged specimens. The AMCC casting characterization program is to be analyzed for their hydrogen behavior. As a result of this program, the basic microstructural factors and fracture characteristics in some cases were analyzed.

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-07-01

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

Recent advances in SRS on hydrogen isotope separation using thermal cycling absorption process

Energy Technology Data Exchange (ETDEWEB)

Xiao, X.; Kit Heung, L.; Sessions, H.T. [Savannah River National Laboratory - SRNL, Aiken, SC (United States)

2015-03-15

TCAP (Thermal Cycling Absorption Process) is a gas chromatograph in principle using palladium in the column packing, but it is unique in the fact that the carrier gas, hydrogen, is being isotopically separated and the system is operated in a semi-continuous manner. TCAP units are used to purify tritium. The recent TCAP advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10 of the current production system's footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects.

Synfuels from fusion: producing hydrogen with the tandem mirror reactor and thermochemical cycles

International Nuclear Information System (INIS)

Ribe, F.L.; Werner, R.W.

1981-01-01

This report examines, for technical merit, the combination of a fusion reactor driver and a thermochemical plant as a means for producing synthetic fuel in the basic form of hydrogen. We studied: (1) one reactor type - the Tandem Mirror Reactor - wishing to use to advantage its simple central cell geometry and its direct electrical output; (2) two reactor blanket module types - a liquid metal cauldron design and a flowing Li 2 O solid microsphere pellet design so as to compare the technology, the thermal-hydraulics, neutronics and tritium control in a high-temperature operating mode (approx. 1200 K); (3) three thermochemical cycles - processes in which water is used as a feedstock along with a high-temperature heat source to produce H 2 and O 2

Improved hydrogen sorption kinetics in wet ball milled Mg hydrides

Energy Technology Data Exchange (ETDEWEB)

Meng, Li

2011-05-04

In this work, wet ball milling method is used in order to improve hydrogen sorption behaviour due to its improved microstructure of solid hydrogen materials. Compared to traditional ball milling method, wet ball milling has benefits on improvement of MgH{sub 2} microstructure and further influences on its hydrogen sorption behavior. With the help of solvent tetrahydrofuran (THF), wet ball milled MgH{sub 2} powder has much smaller particle size and its specific surface area is 7 times as large as that of dry ball milled MgH{sub 2} powder. Although after ball milling the grain size is decreased a lot compared to as-received MgH{sub 2} powder, the grain size of wet ball milled MgH{sub 2} powder is larger than that of dry ball milled MgH{sub 2} powder due to the lubricant effect of solvent THF during wet ball milling. The improved particle size and specific surface area of wet ball milled MgH{sub 2} powder is found to be determining its hydrogen sorption kinetics especially at relatively low temperatures. And it also shows good cycling sorption behavior, which decides on its industrial applicability. With three different catalysts MgH{sub 2} powder shows improved hydrogen sorption behavior as well as the cyclic sorption behavior. Among them, the Nb{sub 2}O{sub 5} catalyst is found to be the most effective one in this work. Compared to the wet ball milled MgH{sub 2} powder, the particle size and specific surface area of the MgH{sub 2} powder with catalysts are similar to the previous ones, while the grain size of the MgH{sub 2} with catalysts is much finer. In this case, two reasons for hydrogen sorption improvement are suggested: one is the reduction of the grain size. The other may be as pointed out in some literatures that formation of new oxidation could enhance the hydrogen sorption kinetics, which is also the reason why its hydrogen capacity is decreased compared to without catalysts. After further ball milling, the specific surface area of wet ball milled Mg

Nuclear hydrogen production and its safe handling

International Nuclear Information System (INIS)

Chung, Hongsuk; Paek, Seungwoo; Kim, Kwang-Rag; Ahn, Do-Hee; Lee, Minsoo; Chang, Jong Hwa

2003-01-01

An overview of the hydrogen related research presently undertaken at the Korea Atomic Energy Research Institute are presented. These encompass nuclear hydrogen production, hydrogen storage, and the safe handling of hydrogen, High temperature gas-cooled reactors can play a significant role, with respect to large-scale hydrogen production, if used as the provider of high temperature heat in fossil fuel conversion or thermochemical cycles. A variety of potential hydrogen production methods for high temperature gas-cooled reactors were analyzed. They are steam reforming of natural gas, thermochemical cycles, etc. The produced hydrogen should be stored safely. Titanium metal was tested primarily because its hydride has very low dissociation pressures at normal storage temperatures and a high capacity for hydrogen, it is easy to prepare and is non-reactive with air in the expected storage conditions. There could be a number of potential sources of hydrogen evolution risk in a nuclear hydrogen production facility. In order to reduce the deflagration detonation it is necessary to develop hydrogen control methods that are capable of dealing with the hydrogen release rate. A series of experiments were conducted to assess the catalytic recombination characteristics of hydrogen in an air stream using palladium catalysts. (author)

Nuclear-produced hydrogen by a thermochemical Cu-Cl plant for passenger hydrogen trains

International Nuclear Information System (INIS)

Marin, G.; Naterer, G.; Gabriel, K.

2010-01-01

This paper compares the technical and economic aspects of electrification of a passenger-train operation in Ontario Canada, versus operation with hydrogen trains using nuclear-produced hydrogen. A local GO Transit diesel operation in Ontario has considered electrification as an alternative to reduce greenhouse gas emissions of passenger trains in the Toronto area. Hydrogen production from nuclear energy via a thermo-chemical Copper-Chlorine (Cu-Cl) cycle for train operation is shown to have lower emissions than direct electrification. It significantly reduces the greenhouse gas emissions compared to diesel operation. A bench-mark reference case used for the nuclear thermo-chemical Cu-Cl cycle is the Sulfur-Iodine (S-I) cycle, under investigation in the USA, Japan, and France, among others. The comparative study in this paper considers a base case of diesel operated passenger trains, within the context of a benefits case analysis for train electrification, for GO Transit operations in Toronto, and the impact of each cost component is discussed. The cost analysis includes projected prices of fuel cell trains, with reference to studies performed by train operators. (author)

Hydrogen mobility from wind energy – A life cycle assessment focusing on the fuel supply

International Nuclear Information System (INIS)

Burkhardt, Jörg; Patyk, Andreas; Tanguy, Philippe; Retzke, Carsten

2016-01-01

Highlights: • Environmental performance, focusing on production and provision of hydrogen. • Primary data collected from a 700 bar refueling station incl. alkaline electrolyser. • Construction of facilities dominates the primary energy demand and emissions. • Refueling station contributes to same extent to GHG emissions as electricity supply. • Remarkably high expenditures for provision of supplies. - Abstract: In the current debates on reducing greenhouse gas emissions in the mobility sector, hydrogen produced via water electrolysis from renewable electricity is commonly regarded to be a sustainable energy carrier with large potential for decarbonisation of the mobility sector. Directly produced at the refueling stations site, hydrogen greenhouse gas emissions are presently defined to be zero in e.g. the Directives of the European Union since emissions arising from the facilities construction are defined to be negligible. In order to check the validity of this assumption with respect to the latest technical developments in hydrogen supply, the present article aims to report the environmental performance of hydrogen being produced and compressed for mobility purposes. To this end, a state-of-the-art hydrogen refueling station (HRS) with an on-site alkaline electrolyser is assessed, which was built and operated in Berlin. Assuming electricity supply from wind energy generation, a life cycle assessment for the complete value chain was carried out where primary data for the build-up of electrolyser and HRS were obtained during decommissioning of the station. The results show that the construction of HRS and on-site electrolyser requires higher material and energy expenditures compared to previous investigations on similar but technically less advanced systems. These expenditures generate a significant footprint in the specific e.g. greenhouse gas emissions if the electrolyser is operated at a reduced load factor as it may be foreseen for grid stabilisation

Hydrogen storage in Mg: a most promising material

International Nuclear Information System (INIS)

Jain, I.P.; Jain, A.; Lal, C.

2009-01-01

hydrides stand as promising candidate for competitive hydrogen storage with reversible hydrogen capacity up to 7.6 wt% for on board applications. Efforts have been devoted to these materials to decrease their desorption temperature, enhance the kinetics and cycle life. The kinetics has been improved by adding an appropriate catalyst into the system as well as by ball milling that introduces defects with improved surface properties. The studies reported promising results, such as improved kinetics and lower desorption temperatures, however, the state of the art materials are still far from meeting the aimed target for their transport applications. Therefore further research work is needed to achieve the goal by improving development on hydrogenation, thermal and cyclic behavior of metal hydrides. In the present article the possibility of commercialization of Mg based alloys has been discussed. (author)

Quantitative separation of the influence of hydrogen bonding of ethanol/water mixture on the shape recovery behavior of polyurethane shape memory polymer

International Nuclear Information System (INIS)

Lu, Haibao; Leng, Jinsong; Min Huang, Wei; Fu, Y Q

2014-01-01

A thermally responsive polyurethane shape memory polymer (SMP) can be actuated in water through a hydrogen bonding interaction between water and the SMP. In this work, we present a comprehensive approach to quantify the hydrogen bonding on the shape recovery behavior of a polyurethane SMP. The stimuli response to the hydrogen bonding of the polyurethane SMP was investigated in ethanol/water mixtures by varying the water content. It was found that depending on the water content, the SMP features a critical hydrogen bonding strength associated with its shape recovery behavior. The Hildebrand solubility parameter theory was employed to quantitatively identify and separate the hydrogen bonding effect of the ethanol/water mixture on the shape recovery ratio and the time. Furthermore, a phenomenological model was developed to predict the glass transition temperature and the shape recovery time of a polyurethane SMP and was verified by the available experimental results. (paper)

LOCAL INTERSTELLAR HYDROGEN'S DISAPPEARANCE AT 1 AU: FOUR YEARS OF IBEX IN THE RISING SOLAR CYCLE

International Nuclear Information System (INIS)

Saul, Lukas; Rodríguez, Diego; Scheer, Juergen; Wurz, Peter; Bzowski, Maciej; Kubiak, Marzena; Sokół, Justina; Fuselier, Stephen; McComas, Dave; Möbius, Eberhard

2013-01-01

NASA's Interstellar Boundary Explorer (IBEX) mission has recently opened a new window on the interstellar medium (ISM) by imaging neutral atoms. One ''bright'' feature in the sky is the interstellar wind flowing into the solar system. Composed of remnants of stellar explosions as well as primordial gas and plasma, the ISM is by no means uniform. The interaction of the local ISM with the solar wind shapes our heliospheric environment with hydrogen being the dominant component of the very local ISM. In this paper, we report on direct sampling of the neutral hydrogen of the local ISM over four years of IBEX observations. The hydrogen wind observed at 1 AU has decreased and nearly disappeared as the solar activity has increased over the last four years; the signal at 1 AU has dropped off in 2012 by a factor of ∼8 to near background levels. The longitudinal offset has also increased with time presumably due to greater radiation pressure deflecting the interstellar wind. We present longitudinal and latitudinal arrival direction measurements of the bulk flow as measured over four years beginning at near solar minimum conditions. The H distribution we observe at 1 AU is expected to be different from that outside the heliopause due to ionization, photon pressure, gravity, and filtration by interactions with heliospheric plasma populations. These observations provide an important benchmark for modeling of the global heliospheric interaction. Based on these observations we suggest a further course of scientific action to observe neutral hydrogen over a full solar cycle with IBEX.

Hydrogen Fuel Cell Vehicles

OpenAIRE

Anton Francesch, Judit

1992-01-01

Hydrogen is an especially attractive transportation fuel. It is the least polluting fuel available, and can be produced anywhere there is water and a clean source of electricity. A fuel cycle in which hydrogen is produced by solar-electrolysis of water, or by gasification of renewably grown biomass, and then used in a fuel-cell powered electric-motor vehicle (FCEV), would produce little or no local, regional, or global pollution. Hydrogen FCEVs would combine the best features of bat...

Fuel cell hybrid taxi life cycle analysis

Energy Technology Data Exchange (ETDEWEB)

Baptista, Patricia, E-mail: patricia.baptista@ist.utl.pt [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Ribau, Joao; Bravo, Joao; Silva, Carla [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Adcock, Paul; Kells, Ashley [Intelligent Energy, Charnwood Building, HolywellPark, Ashby Road, Loughborough, LE11 3GR (United Kingdom)

2011-09-15

A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO{sub 2} emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO{sub 2} emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: > A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. > The hydrogen powered vehicles have the lowest energy consumption and CO{sub 2} emissions results. > A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

Fuel cell hybrid taxi life cycle analysis

International Nuclear Information System (INIS)

Baptista, Patricia; Ribau, Joao; Bravo, Joao; Silva, Carla; Adcock, Paul; Kells, Ashley

2011-01-01

A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO 2 emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO 2 emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: → A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. → The hydrogen powered vehicles have the lowest energy consumption and CO 2 emissions results. → A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

Hydrogen enhanced thermal fatigue of y-titanium aluminide

NARCIS (Netherlands)

Dunfee, William; Gao, Ming; Wei, Robert P.; Wei, W.

1995-01-01

A study of hydrogen enhanced thermal fatigue cracking was carried out for a gamma-based Ti-48Al-2Cr alloy by cycling between room temperature and 750 or 900 °C. The results showed that hydrogen can severely attack the gamma alloy, with resulting lifetimes as low as three cycles, while no failures

Life Cycle Assessment and Water Footprint of Hydrogen Production Methods: From Conventional to Emerging Technologies

Directory of Open Access Journals (Sweden)

Andi Mehmeti

2018-02-01

Full Text Available A common sustainability issue, arising in production systems, is the efficient use of resources for providing goods or services. With the increased interest in a hydrogen (H2 economy, the life-cycle environmental performance of H2 production has special significance for assisting in identifying opportunities to improve environmental performance and to guide challenging decisions and select between technology paths. Life cycle impact assessment methods are rapidly evolving to analyze multiple environmental impacts of the production of products or processes. This study marks the first step in developing process-based streamlined life cycle analysis (LCA of several H2 production pathways combining life cycle impacts at the midpoint (17 problem-oriented and endpoint (3 damage-oriented levels using the state-of-the-art impact assessment method ReCiPe 2016. Steam reforming of natural gas, coal gasification, water electrolysis via proton exchange membrane fuel cell (PEM, solid oxide electrolyzer cell (SOEC, biomass gasification and reforming, and dark fermentation of lignocellulosic biomass were analyzed. An innovative aspect is developed in this study is an analysis of water consumption associated with H2 production pathways by life-cycle stage to provide a better understanding of the life cycle water-related impacts on human health and natural environment. For water-related scope, Water scarcity footprint (WSF quantified using Available WAter REmaining (AWARE method was applied as a stand-alone indicator. The paper discusses the strengths and weaknesses of each production pathway, identify the drivers of environmental impact, quantify midpoint environmental impact and its influence on the endpoint environmental performance. The findings of this study could serve as a useful theoretical reference and practical basis to decision-makers of potential environmental impacts of H2 production systems.

Orbital simulation life tests of nickel hydrogen batteries with additional non-eclipse cycles

Science.gov (United States)

Johnson, P. J.; Donley, S. W.; Verrier, D. C.

Nickel-hydrogen battery technology has established itself as the system of choice to provide energy storage on board Earth orbiting satellites. In addition to providing electrical power for the satellite during the periods the satellite's solar arrays are eclipsed by the Earth, applications are evolving (such as ion propulsion) where the battery is required to supplement the power supplied to the spacecraft by the solar panels in order to meet the peak power demands. In this paper, the results of a four-year accelerated life test programme, equivalent to more than 20 years in orbit, are reported. Additional non-eclipse cycles were added to both the eclipse and solstice seasons of each simulated spacecraft year. The results show that the additional discharges do not significantly effect the rates of performance degradation of the batteries.

Hydrogen assisted cracking and CO2 corrosion behaviors of low-alloy steel with high strength used for armor layer of flexible pipe

Science.gov (United States)

Liu, Zhenguang; Gao, Xiuhua; Du, Linxiu; Li, Jianping; Zhou, Xiaowei; Wang, Xiaonan; Wang, Yuxin; Liu, Chuan; Xu, Guoxiang; Misra, R. D. K.

2018-05-01

In this study, hydrogen induced cracking (HIC), sulfide stress corrosion cracking (SSCC) and hydrogen embrittlement (HE) were carried out to study hydrogen assisted cracking behavior (HIC, SSCC and HE) of high strength pipeline steel used for armor layer of flexible pipe in ocean. The CO2 corrosion behavior of designed steel with high strength was studied by using immersion experiment. The experimental results demonstrate that the corrosion resistance of designed steel with tempered martensite to HIC, SSCC and HE is excellent according to specific standards, which contributes to the low concentration of dislocation and vacancies previously formed in cold rolling process. The corrosion mechanism of hydrogen induced cracking of designed steel, which involves in producing process, microstructure and cracking behavior, is proposed. The designed steel with tempered martensite shows excellent corrosion resistance to CO2 corrosion. Cr-rich compound was first formed on the coupon surface exposed to CO2-saturated brine condition and chlorine, one of the corrosion ions in solution, was rich in the inner layer of corrosion products.

A review of nickel hydrogen battery technology

Energy Technology Data Exchange (ETDEWEB)

Smithrick, J.J.; O`Donnell, P.M. [NASA Lewis Research Center, Cleveland, OH (United States)

1995-12-31

This paper on nickel hydrogen batteries is an overview of the various nickel hydrogen battery design options, technical accomplishments, validation test results and trends. There is more than one nickel hydrogen battery design, each having its advantage for specific applications. The major battery designs are individual pressure vessel (IPV), common pressure vessel (CPV), bipolar and low pressure metal hydride. State-of-the-art (SOA) nickel hydrogen batteries are replacing nickel cadmium batteries in almost all geosynchronous orbit (GEO) applications requiring power above 1 kW. However, for the more severe low earth orbit (LEO) applications (>30,000 cycles), the current cycle life of 4,000 to 10,000 cycles at 60 percent DOD should be improved. A NASA Lewis Research Center innovative advanced design IPV nickel hydrogen cell led to a breakthrough in cycle life enabling LEO applications at deep depths of discharge (DOD). A trend for some future satellites is to increase the power level to greater than 6 kW. Another trend is to decrease the power to less than 1 kW for small low cost satellites. Hence, the challenge is to reduce battery mass, volume and cost. A key is to develop a light weight nickel electrode and alternate battery designs. A common pressure vessel (CPV) nickel hydrogen battery is emerging as a viable alternative to the IPV design. It has the advantage of reduced mass, volume and manufacturing costs. A 10 Ah CPV battery has successfully provided power on the relatively short lived Clementine Spacecraft.

A review of nickel hydrogen battery technology

Science.gov (United States)

Smithrick, John J.; Odonnell, Patricia M.

1995-01-01

This paper on nickel hydrogen batteries is an overview of the various nickel hydrogen battery design options, technical accomplishments, validation test results and trends. There is more than one nickel hydrogen battery design, each having its advantage for specific applications. The major battery designs are individual pressure vessel (IPV), common pressure vessel (CPV), bipolar and low pressure metal hydride. State-of-the-art (SOA) nickel hydrogen batteries are replacing nickel cadmium batteries in almost all geosynchronous orbit (GEO) applications requiring power above 1 kW. However, for the more severe low earth orbit (LEO) applications (greater than 30,000 cycles), the current cycle life of 4000 to 10,000 cycles at 60 percent DOD should be improved. A NASA Lewis Research Center innovative advanced design IPV nickel hydrogen cell led to a breakthrough in cycle life enabling LEO applications at deep depths of discharge (DOD). A trend for some future satellites is to increase the power level to greater than 6 kW. Another trend is to decrease the power to less than 1 kW for small low cost satellites. Hence, the challenge is to reduce battery mass, volume and cost. A key is to develop a light weight nickel electrode and alternate battery designs. A common pressure vessel (CPV) nickel hydrogen battery is emerging as a viable alternative to the IPV design. It has the advantage of reduced mass, volume and manufacturing costs. A 10 Ah CPV battery has successfully provided power on the relatively short lived Clementine Spacecraft. A bipolar nickel hydrogen battery design has been demonstrated (15,000 LEO cycles, 40 percent DOD). The advantage is also a significant reduction in volume, a modest reduction in mass, and like most bipolar designs, features a high pulse power capability. A low pressure aerospace nickel metal hydride battery cell has been developed and is on the market. It is a prismatic design which has the advantage of a significant reduction in volume and a

Electric and hydrogen consumption analysis in plug-in road vehicles

Energy Technology Data Exchange (ETDEWEB)

Ribau, Joao P.; Silva, Carla M.; Faria, Tiago L. [IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, Department of Mechanical Engineering, Av. Rovisco Pais, 1 Pav. Mecanica I, 2 andar, 1049-001 Lisboa (Portugal)

2010-07-01

The main goal of the present study is to analyze some of the capabilities and behavior of two types of plug-in cars: battery electric and hydrogen fuel cell hybrid electric, facing different driving styles, different road gradients, different occupation rates, different electrical loads, and different battery's initial state of charge. In order to do that, four vehicles with different power/weight (kW/kg) ratio (0.044 to 0.150) were simulated in the software ADVISOR, which gives predictions of energy consumption, and behavior of vehicle's power train components (including energy regeneration) along specified driving cycles. The required energy, electricity and/or hydrogen, to overcome the specified driving schedules, allowed to estimate fuel life cycle's CO2 emissions and primary energy. A vehicle with higher power/weight ratio (kW/kg) demonstrated to be less affected in operation and in variation of the energy consumption, facing the different case studies, however may have higher consumptions in some cases. The autonomy, besides depending on the fuel consumption, is directly associated with the type and capacity (kWh) of the chosen battery, plus the stored hydrogen (if fuel cell vehicles are considered, PHEV-FC). The PHEV-FC showed to have higher autonomy than the battery vehicles, but higher energy consumption which is extremely dependent on the type and ratio of energy used, hydrogen or electricity. An aggressive driving style, higher road gradient and increase of weight, required more energy and power to the vehicle and presented consumption increases near to 77%, 621%, 19% respectively. Higher electrical load and battery's initial state of charge, didn't affect directly vehicle's dynamic. The first one drained energy directly from the battery plus demanded a fraction of its power, with energy consumption maximum increasing near 71%. The second one restricted the autonomy without influence directly the energy consumption per

Energy, exergy and economic assessments of a novel integrated biomass based multigeneration energy system with hydrogen production and LNG regasification cycle

International Nuclear Information System (INIS)

Taheri, M.H.; Mosaffa, A.H.; Farshi, L. Garousi

2017-01-01

In this work, a novel integrated biomass based multigeneration energy system is presented and investigated for power, cooling and hydrogen production. The proposed system consists of a combination of biomass integrated gasifier-gas turbine cycle, a Rankine cycle, a cascade organic Rankine cycle, an absorption refrigeration system and a PEM to produce hydrogen. This system uses cold energy of LNG as a thermal sink. Comprehensive thermodynamic and economic analyses as well as an optimization are performed. The effects of operating parameters on thermodynamic performance and total cost rate are investigated for overall system and subsystems. The results show that the fuel mass flow rate is the dominant factor affecting the variation of energy efficiency and total cost rate. An increase in fuel mass flow rate from 4 kg s"−"1 to 10 kg s"−"1 leads to a decrease of 8.5% and an increase of 122.8% overall energy efficiency and total cost rate, respectively. Also, the largest increase in exergy efficiency occurs when gas turbine inlet temperature increases. The results of optimization showed that the highest net power output, mass flow rate of natural gas delivered to city and the flue gas temperature discharged to the environment are obtained for the exergy efficiency optimal design. - Highlights: • A novel multigeneration system is investigated and optimized thermodynamically and economically. • This system is proposed for power, cooling and hydrogen production. • Proposed system uses LNG cold energy thermal sink that can generate power after vaporization. • The effects of operating parameters on energy and exergy efficiencies and total cost rate are investigated. • An optimization is applied based on the energy, exergy and economic viewpoints.

Impact of anode substrates on electrodeposited zinc over cycling in zinc-anode rechargeable alkaline batteries

International Nuclear Information System (INIS)

Wei, Xia; Desai, Divyaraj; Yadav, Gautam G.; Turney, Damon E.; Couzis, Alexander; Banerjee, Sanjoy

2016-01-01

Electrochemical behavior of Ag, Bi, Cu, Fe, Ni and Sn substrates on zinc deposition was evaluated over battery cycling by cyclic voltammetry and electrochemical impedance spectroscopy. The effect of Bi, Cu, Ni, and Sn substrates on zinc electrodeposition during battery cycling was investigated using scanning electron microscopy and X-ray diffraction. The corrosion behavior of each metal in 9 M KOH and the corrosion rates of zinc plated on each substrate were analyzed by Tafel extrapolation method from the potentiodynamic polarization curves and electrochemical impedance spectroscopy. Although the charge-transfer resistance (R_c_t) of zinc electrodeposition is lowest on Sn, Sn eventually corrodes on cycling in alkaline media. Use of Ni as a substrate causes zinc to deteriorate on account of rapid hydrogen evolution. Bi and Cu substrates are more suitable for use as current collectors in zinc-anode alkaline rechargeable batteries because of their low corrosion rate and compact zinc deposition over battery cycling.

Hydrogen transport behavior of beryllium

Energy Technology Data Exchange (ETDEWEB)

Anderl, R.A.; Hankins, M.R.; Longhurst, G.R.; Pawelko, R.J. (Idaho National Engineering Lab., EG and G Idaho, Inc., Idaho Falls, ID (United States)); Macaulay-Newcombe, R.G. (Dept. of Engineering Physics, Univ. Hamilton, ON (Canada))

1992-12-01

Beryllium is being evaluated for use as a plasma-facing material in the International Thermonuclear Experimental Reactor (ITER). One concern in the evaluation is the retention and permeation of tritium implanted into the plasma-facing surface. We performed laboratory-scale studies to investigate mechanisms that influence hydrogen transport and retention in beryllium foil specimens of rolled powder metallurgy product and rolled ingot cast beryllium. Specimen characterization was accomplished using scanning electron microscopy. Auger electron spectroscopy, and Rutherford backscattering spectrometry (RBS) techniques. Hydrogen transport was investigated using ion-beam permeation experiments and nuclear reaction analysis (NRA). Results indicate that trapping plays a significant role in permeation, re-emission, and retention, and that surface processes at both upstream and downstream surfaces are also important. (orig.).

Comparative environmental impact and efficiency assessment of selected hydrogen production methods

Energy Technology Data Exchange (ETDEWEB)

Ozbilen, Ahmet, E-mail: Ahmet.Ozbilen@uoit.ca; Dincer, Ibrahim, E-mail: Ibrahim.Dincer@uoit.ca; Rosen, Marc A., E-mail: Marc.Rosen@uoit.ca

2013-09-15

The environmental impacts of various hydrogen production processes are evaluated and compared, considering several energy sources and using life cycle analysis. The results indicate that hydrogen produced by thermochemical water decomposition cycles are more environmentally benign options compared to conventional steam reforming of natural gas. The nuclear based four-step Cu–Cl cycle has the lowest global warming potential (0.559 kg CO{sub 2}-eq per kg hydrogen production), mainly because it requires the lowest quantity of energy of the considered processes. The acidification potential results show that biomass gasification has the highest impact on environment, while wind based electrolysis has the lowest. The relation is also investigated between efficiency and environmental impacts. -- Highlights: • Environmental performance of nuclear-based hydrogen production is investigated. • The GWP and AP results are compared with various hydrogen production processes. • Nuclear based 4-step Cu–Cl cycle is found to be an environmentally benign process. • Wind-based electrolysis has the lowest AP value.

Hydrogen absorption-desorption properties of Ti0.32Cr0.43V0.25 alloy

International Nuclear Information System (INIS)

Cho, Sung-Wook; Shim, Gunchoo; Choi, Good-Sun; Park, Choong-Nyeon; Yoo, Jeong-Hyun; Choi, Jeon

2007-01-01

Ti 0.32 Cr 0.43 V 0.25 alloy specimens were heat treated, and its various hydrogen storage properties were measured at 303 K to examine its potential as a hydrogen storage material. The heat treatment improved not only the total and the effective hydrogen storage capacities, but also the plateau flatness. The heat of hydride formation was approximately -36 kJ/mol H 2 . The effective hydrogen storage capacity remained at approximately 2 wt% after 1000 cycles of pressure swing cyclic tests. The hydrogen storage capacity could be recovered almost to the initial state by reactivating the alloy. The hydrogen absorption rate increased with the repetition of cycling for the first several cycles and remained almost constant afterward. At the 504th cycle, more than 98% of the hydrogen was absorbed within the first 2 min. X-ray diffraction (XRD) patterns showed that the crystal structure of the alloy became more amorphous as the number of cycles increased

Efficiency of the sulfur-iodine thermochemical water splitting process for hydrogen production based on ADS

International Nuclear Information System (INIS)

Gonzalez, D.; Garcia, L.; Garcia, C.; Garcia, L.; Brayner, C.

2013-01-01

The current hydrogel production is based on fossil fuels; they have a huge contribution to the atmosphere's pollution. thermochemical water splitting cycles don't present this issue because the required process heat is obtained from nuclear energy and therefore, the environmental impact is smaller than using conventional fuels. One of the promising approaches to produce large quantities of hydrogen in an efficient way using nuclear energy is the sulfur-iodine (S-I) thermochemical water splitting cycle. The nuclear source proposed in this paper is a pebble bed gas cooled transmutation facility. Pebble bed very high temperature advanced systems have great perspectives to assume the future nuclear energy. Software based on Chemical Process Simulation (CPS) can be used to simulate the thermochemical water splitting sulfur-iodine cycle for hydrogen production. In this paper, a model for analyzing the sulfur-iodine process sensibility is developed. Efficiency is also calculated and the influence of different parameters on this value. The behavior of the proposed model before different values of initial reactant's flow is analyzed. (Author)

The Italian hydrogen programme

International Nuclear Information System (INIS)

Raffaele Vellone

2001-01-01

Hydrogen could become an important option in the new millennium. It provides the potential for a sustainable energy system as it can be used to meet most energy needs without harming the environment. In fact, hydrogen has the potential for contributing to the reduction of climate-changing emissions and other air pollutants as it exhibits clean combustion with no carbon or sulphur oxide emissions and very low nitrogen oxide emissions. Furthermore, it is capable of direct conversion to electricity in systems such as fuel cells without generating pollution. However, widespread use of hydrogen is not feasible today because of economic and technological barriers. In Italy, there is an ongoing national programme to facilitate the introduction of hydrogen as an energy carrier. This programme aims to promote, in an organic frame, a series of actions regarding the whole hydrogen cycle. It foresees the development of technologies in the areas of production, storage, transport and utilisation. Research addresses the development of technologies for separation and sequestration of CO 2 , The programme is shared by public organisations (research institutions and universities) and national industry (oil companies, electric and gas utilities and research institutions). Hydrogen can be used as a fuel, with significant advantages, both for electric energy generation/ co-generation (thermo-dynamic cycles and fuel cells) and transportation (internal combustion engine and fuel cells). One focus of research will be the development of fuel cell technologies. Fuel cells possess all necessary characteristics to be a key technology in a future economy based on hydrogen. During the initial phase of the project, hydrogen will be derived from fossil sources (natural gas), and in the second phase it will be generated from renewable electricity or nuclear energy. The presentation will provide a review of the hydrogen programme and highlight future goals. (author)

Correlation between Fatigue Crack Growth Behavior and Fracture Surface Roughness on Cold-Rolled Austenitic Stainless Steels in Gaseous Hydrogen

Directory of Open Access Journals (Sweden)

Tai-Cheng Chen

2018-03-01

Full Text Available Austenitic stainless steels are often considered candidate materials for use in hydrogen-containing environments because of their low hydrogen embrittlement susceptibility. In this study, the fatigue crack growth behavior of the solution-annealed and cold-rolled 301, 304L, and 310S austenitic stainless steels was characterized in 0.2 MPa gaseous hydrogen to evaluate the hydrogen-assisted fatigue crack growth and correlate the fatigue crack growth rates with the fracture feature or fracture surface roughness. Regardless of the testing conditions, higher fracture surface roughness could be obtained in a higher stress intensity factor (∆K range and for the counterpart cold-rolled specimen in hydrogen. The accelerated fatigue crack growth of 301 and 304L in hydrogen was accompanied by high fracture surface roughness and was associated with strain-induced martensitic transformation in the plastic zone ahead of the fatigue crack tip.

Thermochemical hydrogen production based on magnetic fusion

International Nuclear Information System (INIS)

Krikorian, O.H.; Brown, L.C.

1982-01-01

Conceptual design studies have been carried out on an integrated fusion/chemical plant system using a Tandem Mirror Reactor fusion energy source to drive the General Atomic Sulfur-Iodine Water-Splitting Cycle and produce hydrogen as a future feedstock for synthetic fuels. Blanket design studies for the Tandem Mirror Reactor show that several design alternatives are available for providing heat at sufficiently high temperatures to drive the General Atomic Cycle. The concept of a Joule-boosted decomposer is introduced in one of the systems investigated to provide heat electrically for the highest temperature step in the cycle (the SO 3 decomposition step), and thus lower blanket design requirements and costs. Flowsheeting and conceptual process designs have been developed for a complete fusion-driven hydrogen plant, and the information has been used to develop a plot plan for the plant and to estimate hydrogen production costs. Both public and private utility financing approaches have been used to obtain hydrogen production costs of $12-14/GJ based on July 1980 dollars

Metal oxide-hydrogen secondary battery; Kinzoku sankabutsu-suiso niji denchi

Energy Technology Data Exchange (ETDEWEB)

Hosobuchi, H.; Edoi, M.; Katsumata, T.

1995-06-06

Recently, the metal oxide - hydrogen secondary battery characterized by employing the hydrogen storage alloy as the hydrogen negative electrode draws attention. However, the secondary batteries equipped with the negative electrode composed of hydrogen storage alloy powder have such shortcoming that the charge-discharge cycle life is rather short and it changes widely from battery to battery, as the hydrogen storage alloy is disintegrated. This invention solves the problem. Employing the alloy having a composition expressed as LmNi(w)Co(X)Mn(y)Al(z) (Lm = rare earth elements including La) can suppress the disintegration of hydrogen storage alloy powder during the charge-discharge cycle. In addition, controlling the oxygen content in the hydrogen storage alloy powder to 500 - 1500ppm can reduce the oxidation corrosion of the hydrogen storage alloy, resulting in suppression of its deterioration. 1 fig., 2 tabs.

Assessment of thermochemical hydrogen production. Project 8994 mid-contract progress report, July 1--November 1, 1977. [Iron chloride and copper sulfate cycles

Energy Technology Data Exchange (ETDEWEB)

Dafler, J.R.; Foh, S.E.; Schreiber, J.D.

1977-12-01

We have completed the base-case (first-cut) flowsheet analysis for two thermochemical water-splitting cycles that have been under study at the Institute of Gas Technology: a four-step iron chloride cycle (denoted B-1) and a four-step copper sulfate cycle (denoted H-5). In the case of Cycle B-1, an energy balance has located the worst problem areas in the cycle, and flowsheet modifications have begun. Calculations of equilibrium effects due to the hydrolysis of ferrous chloride at pressures high enough to interface with projected hydrogen transmission systems will, apparently, necessitate higher temperature process heat input for this step. Higher pressure operation of some critical separation processes yields more favorable heat balances. For Cycle H-5, the unmodified (base-case) flowsheet indicates that reaction product separations will be relatively simple with respect to Cycle B-1. Work of Schuetz and others dealing with the electrolysis and thermodynamics of HBr/H/sub 2/O/SO/sub 2/ systems is being extensively reviewed. Work plans for this part of the contract are currently being reviewed.

Cathodic cycling effects in the oxide films formed on zirconium alloys type AB2

International Nuclear Information System (INIS)

Zerbino, J.O; Visintin, A; Triaca, W

2003-01-01

The passive behavior of ZrNi alloys near the rest potential is studied through in situ voltammetry, ellipsometry, and microscopic observation.A significant oxide layer growth is observed in aqueous 1 M KOH during the application of different potential programs currently used in the activation processes of the alloy.The understanding of both the alloy activation process and the hydrogen absorption process is important in the strategies employed for the design of electrodes for nickel metal hydride batteries.The kinetics of the oxide layer formation, under potential cycling in the cathodic region related to the rest potential, plays a significant role in the activation process of metal alloy.Cathodic potential cycling increases the thickness and decreases the compactness of the passive oxide layer.The protonation of the oxide decreases the barrier effect and makes the anodic polarization more effective.Potential cycling gives rise to increasing surface oxidation, hydrogen absorption and hydride formation, and produces the consequent fragmentation of the material mainly through grain limits (J.Solid State Eletrochem. in press)

The influence of hydrogen on the deformation behavior of zircaloy 4

International Nuclear Information System (INIS)

Flanagan, M. E.; Koss, D. A.; Motta, A. T.

2008-01-01

The deformation behavior of Zr based cladding forms a basis for fuel behavior codes and affects failure criteria; as such, it is critical to reactor safety. The present study examines the influence of hydrogen on the uniaxial deformation behavior of hydrided cold worked and stress relieved Zircaloy 4 plate material. Specimens of various orientations (i.e., stress axis aligned with the rolling direction, the transverse direction, or normal to the plate surface direction) were tested in compression at a range of temperatures (25 .deg. , 300 .deg. , and 400 .deg. C), and strain rates (from 10-4/s to 10-1/s). Contrasting the deformation behavior of the material containing ∼45 wt ppm H with that of the material containing ∼420 wt. ppm H shows that increasing H content (a) causes a small decrease in the 0.2% yield stress that is eliminated at 1.0% flow stress, (b) increases the strain hardening in the rolling direction but not in the other orientations, (c) has no effect on the temperature dependence of the strain hardening, and (d) does not affect the strain rate hardening behavior. Increasing H content also has no observable effect on the high degree of plastic anisotropy of this plate material which is manifested in difficult through thickness deformation, resulting in high flow stresses for specimens oriented in the normal to plate surface direction

Notch Effect on Tensile Deformation Behavior of 304L and 316L Steels in Liquid Helium and Hydrogen

International Nuclear Information System (INIS)

Shibata, K.; Fujii, H.

2004-01-01

Tensile tests of type 304L and 316L steels were carried out using round bar specimens with a notch in liquid helium, hydrogen, liquid nitrogen and at ambient temperature. The obtained tensile strengths were compared with the tensile strengths of smooth specimens. For smooth specimens, tensile strength increased with a decrease in temperature and the strengths in liquid helium and hydrogen show similar values in both steels. For notched specimen of 304L steel, tensile strength (including fracture strength) increased noticeably from ambient to liquid nitrogen temperature but showed a large decrease in liquid helium and hydrogen. In liquid hydrogen and helium, the tensile strength is a little lower in liquid hydrogen than in liquid helium and both strengths are lower than tensile strengths of smooth specimens. For notched specimen of 316L steel, an increase in tensile strength from ambient to liquid nitrogen temperature was not so large and a decrease from liquid nitrogen to liquid hydrogen was small. The tensile strengths in liquid helium and hydrogen were nearly same and higher than those of smooth specimens. Different behavior of serration was observed between liquid helium and hydrogen, and between 304L and 316L steels. The reasons for these differences were discussed using computer simulation

Hydrogen Storage Characteristics of CNT doped NaAlH4

International Nuclear Information System (INIS)

Pukazhselvan, D.; Sterlin Leo Hudson, M.; Bipin Kumar Gupta; Srivastava, O.N.

2006-01-01

The current Hydrogen based energy infrastructure required a high energy density consumer friendly hydrogen storage media. Although the desired goals for the hydrogen fueled vehicular transport has not yet met by any hydrogen storage material, complex Sodium Alanate is said to be a promising candidate under this demand due to its high hydrogen storage capacity and the thermodynamically permissible reversible hydrogen storage capacity. However its poor sorption behavior under moderate conditions (NaAlH 4 →Na 3 AlH 6 ; 3.7 wt % vs 50 hrs at ∼170 C and Na 3 AlH 6 →NaH; 1.85 wt % vs 30 hrs at ∼220 C) urges their limited uses in ages. But these limitations can be removed by using catalysts particularly transition elements but the location of catalyst in NaAlH 4 matrix and the possible mechanism is not yet clearly understood. The aim of the present investigation is to improve the overall sorption characteristics of NaAlH 4 by a new light weighted high surface area (1315 sq mtr/gm) material (CNT) admixing and to obtain a best doping level to NaAlH 4 . So far only Ti has been attempted as a suitable catalyst. It is believed that the high surface area of CNT can provide an additional solid-gas (H 2 ) surface/interface and it can produce thermal contact between grains (thermal conductivity Kth of MWCNT: 3000 w/k and Kth of NaAlH 4 : 0.32 w/k) for stimulating their thermally activated dissociation in NaAlH 4 . In parallel with this approach XRD of NaAlH 4 reveals that there was no change in lattice structure after doping by CNT, SEM picture depicts that CNT precipitation in grain surfaces. Catalytic concentration of various mole % of x values finds that x = 8 is the best doping level as it gives 3.3 wt % of hydrogen within 2 hrs. The comparative sorption behavior with Ti:NaAlH 4 also shows CNTs as an optimum alternative catalyst to NaAlH 4 and besides this CNT doped desorbed ingredients shown good re-hydrogenation behavior(3.7 wt % at 8. cycle and 4.2 wt % maximum at

Use of nuclear energy for hydrogen production

International Nuclear Information System (INIS)

Axente, Damian

2006-01-01

Full text: The potentials of three hydrogen production processes under development for the industrial production of hydrogen using nuclear energy, namely the advanced electrolysis the steam reforming, the sulfur-iodine water splitting cycle, are compared and evaluated in this paper. Water electrolysis and steam reforming of methane are proven and used extensively today for the production of hydrogen. The overall thermal efficiency of the electrolysis includes the efficiency of the electrical power generation and of the electrolysis itself. The electrolysis process efficiency is about 75 % and of electrical power generation is only about 30 %, the overall thermal efficiency for H 2 generation being about 25 %. Steam reforming process consists of reacting methane (or natural gas) and steam in a chemical reactor at 800-900 deg. C, with a thermal efficiency of about 70 %. In a reforming process, with heat supplied by nuclear reactor, the heat must be supplied by a secondary loop from the nuclear side and be transferred to the methane/steam mixture, via a heat exchanger type reactor. The sulfur-iodine cycle, a thermochemical water splitting, is of particular interest because it produces hydrogen efficiently with no CO 2 as byproduct. If heated with a nuclear source it could prove to be an ideal environmental solution to hydrogen production. Steam reforming remains the cheapest hydrogen production method based on the latest estimates, even when implemented with nuclear reactor. The S-I cycle offers a close second solution and the electrolysis is the most expensive of the options for industrial H 2 production. The nuclear plant could power electrolysis operations right away; steam reforming with nuclear power is a little bit further off into the future, the first operation with nuclear facility is expected to have place in Japan in 2008. The S-I cycle implementation is still over the horizon, it will be more than 10 years until we will see that cycle in full scale

Thermomechanical behavior modeling and experimental validation of polymer-wound composite multi-layers. Hydrogen storage application

International Nuclear Information System (INIS)

Gentilleau, Benoit

2012-01-01

The purpose of this research is to study the thermomechanical behavior of the constituent materials of a type IV hydrogen storage tank: a composite, ensuring the strength, is wound around the polyurethane liner that ensures sealing of the tank and thermal insulation; at the extremities, stainless steel parts are used to allow the process connection. In this type of tank, during filling, there is a significant increase in hydrogen temperature, resulting in a gradual heating of the structure and the presence of temperature gradients. The purpose of this study is primarily to characterize the behavior of such a structure when subjects to complex thermomechanical loading. Initially, mechanical and thermal characterization tests have been made over the service life range of temperature of the tank to obtain the necessary data for the realization of a thermomechanical numerical model. Then, a behavior law of the composite, easily transferable to a complex structure such as the whole tank and taking into account the non-linearity, the matrix damage, the progressive loss of shear modulus, and the thermo-dependence of the materials parameters, is developed. The tests on technological representative specimens have been performed to better understand the mechanisms that can appear in the tank and to validate the model. Finally, a numerical study of a tank was performed. The coupled influence of temperature and damage matrix on the behavior of this structure is analyzed. (author)

Thermodynamic efficiency analysis and cycle optimization of deeply precooled combined cycle engine in the air-breathing mode

Science.gov (United States)

Zhang, Jianqiang; Wang, Zhenguo; Li, Qinglian

2017-09-01

The efficiency calculation and cycle optimization were carried out for the Synergistic Air-Breathing Rocket Engine (SABRE) with deeply precooled combined cycle. A component-level model was developed for the engine, and exergy efficiency analysis based on the model was carried out. The methods to improve cycle efficiency have been proposed. The results indicate cycle efficiency of SABRE is between 29.7% and 41.7% along the flight trajectory, and most of the wasted exergy is occupied by the unburned hydrogen in exit gas. Exergy loss exists in each engine component, and the sum losses of main combustion chamber(CC), pre-burner(PB), precooler(PC) and 3# heat exchanger(HX3) are greater than 71.3% of the total loss. Equivalence ratio is the main influencing factor of cycle, and it can be regulated by adjusting parameters of helium loop. Increase the maximum helium outlet temperature of PC by 50 K, the total assumption of hydrogen will be saved by 4.8%, and the cycle efficiency is advanced by 3% averagely in the trajectory. Helium recirculation scheme introduces a helium recirculation loop to increase local helium flow rate of PC. It turns out the total assumption of hydrogen will be saved by 9%, that's about 1740 kg, and the cycle efficiency is advanced by 5.6% averagely.

Future outlook of hydrogen market

International Nuclear Information System (INIS)

Ozmen, S.; Leprince, P.

1976-01-01

Up to now, hydrogen has been produced from hydrocarbons for chemical uses. In the future, it will have to find a new market for itself which will depend on the development of nuclear power plants. Through the use of electric or thermal energy available during off-peak hours, water decomposition by electrolytic or thermal methods (redox cycle) could produce hydrogen, a storable and transportable gas. In addition to hydrogen consumption for chemical uses (methanol and ammonia manufacturing, petroleum fraction processing, metallurgy, etc.) plans are being drawn up to use hydrogen as a vehicle for energy [fr

Study on transient hydrogen behavior and effect on passive containment cooling system of the advanced PWR

International Nuclear Information System (INIS)

Wang Yan

2014-01-01

A certain amount of hydrogen will be generated due to zirconium-steam reaction or molten corium concrete interaction during severe accidents in the pressurized water reactor (PWR). The generated hydrogen releases into the containment, and the formed flammable mixture might cause deflagration or detonation to produce high thermal and pressure loads on the containment, which may threaten the integrity of the containment. The non-condensable hydrogen in containment may also reduce the steam condensation on the containment surface to affect the performance of the passive containment cooling system (PCCS). To study the transient hydrogen behavior in containment with the PCCS performance during the accidents is significant for the further study on the PCCS design and the hydrogen risk mitigation. In this paper, a new developed PCCS analysis code with self-reliance intellectual property rights, which had been validated by comparison on the transients in the containment during the design basis accidents with other developed PCCS analysis code, is brief introduced and used for the transient simulation in the containment under a postulated small break LOCA of cold-leg. The results show that the hydrogen will flow upwards with the coolant released from the break and spread in the containment by convection and diffusion, and it results in the increase of the pressure in the containment due to reducing the heat removal capacity of the PCCS. (author)

Healing behavior of preexisting hydrogen micropores in aluminum alloys during plastic deformation

International Nuclear Information System (INIS)

Toda, H.; Minami, K.; Koyama, K.; Ichitani, K.; Kobayashi, M.; Uesugi, K.; Suzuki, Y.

2009-01-01

Synchrotron X-ray microtomography was used to observe the shrinkage and annihilation behaviors of hydrogen micropores in three dimensions during hot and cold plastic deformation of an Al-Mg alloy. Whether complete healing of micropores is achieved after plastic deformation was examined by exposing the material to a high temperature after plastic deformation. Although micropores generally show a pattern of shrinking and closing, closer inspection of a single specimen revealed a variety of geometrically variable behaviors. It is noteworthy that some of the micropores are reinitiated in positions identical to those before their annihilation, even after an 8-22% macroscopic strain has been further applied after annihilation. We attribute local variations such as these to significant local strain variation, which we measured in a series of tomographic volumes by tracking the microstructural features.

Contribution to the study of new hydrogen production, purification and storage processes

International Nuclear Information System (INIS)

Manaud, Jean-Pierre

1984-01-01

This research thesis addresses the various aspects of hydrogen production, purification and process within the scope of hydrogen-based energy production. Hydrogen production is achieved by water decomposition through a thermo-chemical process. The author reports the thermodynamic assessment of a water decomposition thermo-chemical cycle for chlorine and sulphur-related cycles. He reports the experimental investigation of hydrogen purification by selective diffusion, the study of contamination of a CeMg12 alloy by nitrogen, oxygen and water vapour with application to hydrogen storage under the form of hydrides [fr

Damage behavior of SnAgCu/Cu solder joints subjected to thermomechanical cycling

International Nuclear Information System (INIS)

Xiao, H.; Li, X.Y.; Hu, Y.; Guo, F.; Shi, Y.W.

2013-01-01

Highlights: •A creep–fatigue damage model based on CDM was proposed. •Designed system includes load frame, strain measure device and damage test device. •Damage evolution of solder joints was a function of accumulated inelastic strain. •Damage of solder joints is an interaction between creep and low-cycle fatigue. -- Abstract: Thermomechanical fatigue damage is a progressive process of material degradation. The objective of this study was to investigate the damage behavior of SnAgCu/Cu solder joints under thermomechanical cycling. A damage model was proposed based on continuum damage mechanics (CDM). Based upon an analysis of displacements for flip-chip solder joints subjected to thermal cycling, a special bimetallic loading frame with single-solder joint samples was designed to simulate the service conditions of actual joints in electronic packages. The assembly, which allowed for strain measurements of an individual solder joint during temperature cycling, was used to investigate the impact of stress–strain cycling on the damage behavior of SnAgCu/Cu solder joints. The characteristic parameters of the damage model were determined through thermomechanical cycling and strain measurement tests. The damage variable D = 1 − R 0 /R was selected, and values for it were obtained using a four-probe method for the single-solder joint samples every dozen cycles during thermomechanical cycling tests to verify the model. The results showed that the predicted damage was in good agreement with the experimental results. The damage evolution law proposed here is a function of inelastic strain, and the results showed that the damage rate of SnAgCu/Cu solder joints increased as the range of the applied strain increased. In addition, the microstructure evolution of the solder joints was analyzed using scanning electron microscopy, which provided the microscopic explanation for the damage evolution law of SnAgCu/Cu solder joints

Damage behavior of SnAgCu/Cu solder joints subjected to thermomechanical cycling

Energy Technology Data Exchange (ETDEWEB)

Xiao, H., E-mail: xiaohui2013@yahoo.com.cn; Li, X.Y.; Hu, Y.; Guo, F.; Shi, Y.W.

2013-11-25

Highlights: •A creep–fatigue damage model based on CDM was proposed. •Designed system includes load frame, strain measure device and damage test device. •Damage evolution of solder joints was a function of accumulated inelastic strain. •Damage of solder joints is an interaction between creep and low-cycle fatigue. -- Abstract: Thermomechanical fatigue damage is a progressive process of material degradation. The objective of this study was to investigate the damage behavior of SnAgCu/Cu solder joints under thermomechanical cycling. A damage model was proposed based on continuum damage mechanics (CDM). Based upon an analysis of displacements for flip-chip solder joints subjected to thermal cycling, a special bimetallic loading frame with single-solder joint samples was designed to simulate the service conditions of actual joints in electronic packages. The assembly, which allowed for strain measurements of an individual solder joint during temperature cycling, was used to investigate the impact of stress–strain cycling on the damage behavior of SnAgCu/Cu solder joints. The characteristic parameters of the damage model were determined through thermomechanical cycling and strain measurement tests. The damage variable D = 1 − R{sub 0}/R was selected, and values for it were obtained using a four-probe method for the single-solder joint samples every dozen cycles during thermomechanical cycling tests to verify the model. The results showed that the predicted damage was in good agreement with the experimental results. The damage evolution law proposed here is a function of inelastic strain, and the results showed that the damage rate of SnAgCu/Cu solder joints increased as the range of the applied strain increased. In addition, the microstructure evolution of the solder joints was analyzed using scanning electron microscopy, which provided the microscopic explanation for the damage evolution law of SnAgCu/Cu solder joints.

Hydrogen isotope effect on storage behavior of U{sub 2}Ti and UZr{sub 2.3}

Energy Technology Data Exchange (ETDEWEB)

Jat, Ram Avtar; Sawant, S.G.; Rajan, M.B.; Dhanuskar, J.R. [Product Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Kaity, Santu [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Parida, S.C., E-mail: sureshp@barc.gov.in [Product Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2013-11-15

U{sub 2}Ti and UZr{sub 2.3} alloys were prepared by arc melting method, vacuum annealed and characterized by XRD, SEM and EDX methods. Hydrogen isotope effect on the storage behavior of these alloys were studied by measuring the hydrogen/deuterium desorption pressure–composition–temperature (PCT) profiles in the temperature range of 573–678 K using a Sievert’s type volumetric apparatus. It was observed that, in the temperature and pressure range of investigation, all the isotherms show a single desorption plateau. The PCT data reveals that both U{sub 2}Ti and UZr{sub 2.3} alloys had normal isotope effects on hydrogen/deuterium desorption at all experimental temperatures. Thermodynamic parameters for dehydrogenation and dedeuteration reactions of the corresponding hydrides and deuterides of the above alloys were deduced from the PCT data.

Enhanced hydrogen storage in sandwich-structured rGO/Co1-xS/rGO hybrid papers through hydrogen spillover

Science.gov (United States)

Han, Lu; Qin, Wei; Jian, Jiahuang; Liu, Jiawei; Wu, Xiaohong; Gao, Peng; Hultman, Benjamin; Wu, Gang

2017-08-01

Reduced graphene oxide (rGO) based two-dimensional (2D) structures have been fabricated for electrochemical hydrogen storage. However, the effective transfer of atomic hydrogen to adjacent rGO surfaces is suppressed by binders, which are widely used in conventional electrochemical hydrogen storage electrodes, leading to a confining of the performance of rGO for hydrogen storage. As a proof of concept experiment, a novel strategy is developed to fabricate the binder-free sandwich-structured rGO/Co1-xS/rGO hybrid paper via facile ball milling and filtration process. Based on the structure investigation, Co1-xS is immobilized in the space between the individual rGO sheets by the creation of chemical "bridges" (Csbnd S bonds). Through the Csbnd S bonds, the atomic hydrogen is transferred from Co1-xS to rGO accompanying a Csbnd H chemical bond formation. When used as an electrode, the hybrid paper exhibits an improved hydrogen storage capacity of 3.82 wt% and, most importantly, significant cycling stability for up to 50 cycles. Excluding the direct hydrogen storage contribution from the Co1-xS in the hybrid paper, the hydrogen storage ability of rGO is enhanced by 10× through the spillover effects caused by the Co1-xS modifier.

Ultrafine hydrogen storage powders

Science.gov (United States)

Anderson, Iver E.; Ellis, Timothy W.; Pecharsky, Vitalij K.; Ting, Jason; Terpstra, Robert; Bowman, Robert C.; Witham, Charles K.; Fultz, Brent T.; Bugga, Ratnakumar V.

2000-06-13

A method of making hydrogen storage powder resistant to fracture in service involves forming a melt having the appropriate composition for the hydrogen storage material, such, for example, LaNi.sub.5 and other AB.sub.5 type materials and AB.sub.5+x materials, where x is from about -2.5 to about +2.5, including x=0, and the melt is gas atomized under conditions of melt temperature and atomizing gas pressure to form generally spherical powder particles. The hydrogen storage powder exhibits improved chemcial homogeneity as a result of rapid solidfication from the melt and small particle size that is more resistant to microcracking during hydrogen absorption/desorption cycling. A hydrogen storage component, such as an electrode for a battery or electrochemical fuel cell, made from the gas atomized hydrogen storage material is resistant to hydrogen degradation upon hydrogen absorption/desorption that occurs for example, during charging/discharging of a battery. Such hydrogen storage components can be made by consolidating and optionally sintering the gas atomized hydrogen storage powder or alternately by shaping the gas atomized powder and a suitable binder to a desired configuration in a mold or die.

Process chemistry related to hydrogen isotopes

International Nuclear Information System (INIS)

Iwasaki, Matae; Ogata, Yukio

1991-01-01

Hydrogen isotopes, that is, protium, deuterium and tritium, are all related deeply to energy in engineering region. Deuterium and tritium exist usually as water in extremely thin state. Accordingly, the improvement of the technology for separating these isotopes is a large engineering subject. Further, tritium is radioactive and its half-life period is 12.26 years, therefore, it is desirable to fix it in more stable form besides its confinement in the handling system. As the chemical forms of hydrogen, the molecular hydrogen with highest reactivity, metal hydride, carbon-hydrogen-halogen system compounds, various inorganic hydrides, most stable water and hydroxides are enumerated. The grasping of the behavior from reaction to stable state of these hydrogen compounds and the related materials is the base of process chemistry. The reaction of exchanging isotopes between water and hydrogen on solid catalyzers, the decomposition of ethane halide containing hydrogen, the behavior of water and hydroxides in silicates are reported. The isotope exchange between water and hydrogen is expected to be developed as the process of separating and concentrating hydrogen isotopes. (K.I.) 103 refs

Adsorption process to recover hydrogen from feed gas mixtures having low hydrogen concentration

Science.gov (United States)

Golden, Timothy Christopher; Weist, Jr., Edward Landis; Hufton, Jeffrey Raymond; Novosat, Paul Anthony

2010-04-13

A process for selectively separating hydrogen from at least one more strongly adsorbable component in a plurality of adsorption beds to produce a hydrogen-rich product gas from a low hydrogen concentration feed with a high recovery rate. Each of the plurality of adsorption beds subjected to a repetitive cycle. The process comprises an adsorption step for producing the hydrogen-rich product from a feed gas mixture comprising 5% to 50% hydrogen, at least two pressure equalization by void space gas withdrawal steps, a provide purge step resulting in a first pressure decrease, a blowdown step resulting in a second pressure decrease, a purge step, at least two pressure equalization by void space gas introduction steps, and a repressurization step. The second pressure decrease is at least 2 times greater than the first pressure decrease.

Low Cycle Fatigue Behavior of Alloy617 Weldment at 850°C

Energy Technology Data Exchange (ETDEWEB)

Hwang, Jeong Jun; Kim, Seon Jin [Pukyong Nat’l Univ., Busan (Korea, Republic of); Kim, Woo Gon; Kim, Eung-Seon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-03-15

Alloy 617 is one of the primary candidate materials to be used in a very high temperature reactor (VHTR) system as an intermediate heat exchanger (IHX). To investigate the low cycle fatigue behavior of Alloy 617 weldments at a high temperature of 850℃, fully reversed strain-controlled fatigue tests were conducted with the total strain values ranging from 0.6~1.5%. The weldment specimens were machined using the weld pads fabricated with a single V-grove configuration by gas tungsten arc welding (GTAW) process. The fatigue life is reduced as the total strain range increases. For all testing conditions, the cyclic stress response behavior of the Alloy 617 weldments exhibited the initial cyclic strain hardening phenomenon during the initial small number of cycles. Furthermore, the overall fatigue cracking and the propagation or cracks showed a transgranular failure mode.

Collective behaviors of suprachiasm nucleus neurons under different light—dark cycles

International Nuclear Information System (INIS)

Gu Chang-Gui; Liu Zong-Hua; Zhang Xin-Hua

2014-01-01

The principal circadian clock in the suprachiasm nucleus (SCN) regulates the circadian rhythm of physiological and behavioral activities of mammals. Except for the normal function of the circadian rhythm, the ensemble of SCN neurons may show two collective behaviors, i.e., a free running period in the absence of a light—dark cycle and an entrainment ability to an external T cycle. Experiments show that both the free running periods and the entrainment ranges may vary from one species to another and can be seriously influenced by the coupling among the SCN neurons. We here review the recent progress on how the heterogeneous couplings influence these two collective behaviors. We will show that in the case of homogeneous coupling, the free running period increases monotonically while the entrainment range decreases monotonically with the increase of the coupling strength. While in the case of heterogenous coupling, the dispersion of the coupling strength plays a crucial role. It has been found that the free running period decreases with the increase of the dispersion while the entrainment ability is enhanced by the dispersion. These findings provide new insights into the mechanism of the circadian clock in the SCN. (topical review - statistical physics and complex systems)

Sex steroid hormones during the ovarian cycle of an all-female, parthenogenetic lizard and their correlation with pseudosexual behavior.

Science.gov (United States)

Moore, M C; Whittier, J M; Crews, D

1985-11-01

Cnemidophorus uniparens is a unisexual lizard that reproduces by parthenogenesis. Individuals of this species display male-like and female-like copulatory behaviors during different phases of the ovarian cycle suggesting that these pseudocopulatory behaviors are hormonally activated. To learn more about both the endocrinology of parthenogenesis and the possible hormonal activation of male-like copulatory behavior in female individuals, we (1) characterized changes in plasma levels of the sex steroid hormones progesterone, 5 alpha-dihydrotestosterone, testosterone, and 17 beta-estradiol during the ovarian cycle in both free-living and captive individuals, and (2) measured sex steroid hormones in plasma collected from captive individuals immediately after they expressed male-like or female-like copulatory behavior. In general, the pattern of secretion of ovarian hormones in C. uniparens appears to be similar to that of other oviparous vertebrates with similar reproductive cycles. Estradiol is elevated only during the preovulatory phase, whereas progesterone increases slightly during vitellogenesis and then increases dramatically following ovulation. Circulating levels of androgen are very low and are generally below the sensitivity of our radioimmunoassay at all stages of the ovarian cycle. The hormonal correlates of female-like copulatory behavior suggest that, as in other vertebrates, female receptivity is activated by a synergism of estradiol and progesterone. There is no evidence that the hormonal cycle has been altered to produce elevated levels of androgens during the phase of the cycle when male-like behavior is expressed. Rather it seems more likely that the central nervous system has evolved a novel response to a typical pattern of ovarian steroid hormone secretion. At present, the best hormonal correlate of male-like behavior is that changes in plasma levels of progesterone closely parallel changes in probability of expressing male-like behavior.

KOH concentration effect on cycle life of nickel-hydrogen cells. III - Cycle life test

Science.gov (United States)

Lim, H. S.; Verzwyvelt, S. A.

1988-01-01

A cycle life test of Ni/H2 cells containing electrolytes of various KOH concentrations and a sintered type nickel electrode was carried out at 23 C using a 45 min accelerated low earth orbit (LEO) cycle regime at 80 percent depth of discharge. One of three cells containing 26 percent KOH has achieved over 28,000 cycles, and the other two 19,000 cycles, without a sign of failure. Two other cells containing 31 percent KOH electrolyte, which is the concentration presently used in aerospace cells, failed after 2,979 and 3,620 cycles. This result indicates that the cycle life of the present type of Ni/H2 cells may be extended by a factor of 5 to 10 simply by lowering the KOH concentration. Long cycle life of a Ni/H2 battery at high depth-of-discharge operation is desired, particularly for an LEO spacecraft application. Typically, battery life of about 30,000 cycles is required for a five year mission in an LEO. Such a cycle life with presently available cells can be assured only at a very low depth-of-discharge operation. Results of testing already show that the cycle life of an Ni/H2 cell is tremendously improved by simply using an electrolyte of low KOH concentration.

Proposal of emergency systems for the liberations control in a hydrogen producer plant with the cycle S-I

International Nuclear Information System (INIS)

Ruiz S, T.; Francois, J. L.; Nelson, P. F.; Cruz G, M. J.

2012-10-01

At present, one of the processes that theoretically has demonstrated to be of the most efficient for the hydrogen production is the thermal-chemistry cycle Sulfur-Iodine (S-I) coupled to a nuclear reactor of very high temperature (VHTR). Because this chemical process of hydrogen production requires of a great inventory of toxic materials (sulfurous compounds, hydriodic acid and iodine) is necessary the emergency systems design with the purpose of protecting the facilitates and equipment s, the atmosphere and population. Inside the important considerations for this design are the obtained results in the liberations simulations of the substances involved in the process. These simulations were realized with the computer code Phast, including the leak through a small failure of the pipe, as well as the catastrophic failure. To determine the good localization of the equipment s, as well as the inventory required for the liberations control. The operation conditions were taken of a combination of the preliminary design proposed by the General Atomics and the optimized conditions by the Korea Advanced Institute of Science and Technology, considering a hydrogen production of 1 kg-mol/s. The proposed materials for the neutralization of the liberated substances were selected considering that they did not increase the inventory of process toxic substances. (Author)

HTTR hydrogen production system. Structure and main specifications of mock-up test facility (Contract research)

International Nuclear Information System (INIS)

Kato, Michio; Aita, Hideki; Inagaki, Yoshiyuki; Hayashi, Koji; Ohashi, Hirofumi; Sato, Hiroyuki; Iwatsuki, Jin; Takada, Shoji; Inaba, Yoshitomo

2007-03-01

The mock-up test facility was fabricated to investigate performance of the steam generator for mitigation of the temperature fluctuation of helium gas and transient behavior of the hydrogen production system for HTTR and to obtain experimental data for verification of a dynamic analysis code. The test facility has an approximate hydrogen production capacity of 120Nm 3 /h and the steam reforming process of methane; CH 4 +H 2 O=3H 2 +CO, was used for hydrogen production of the test facility. An electric heater was used as a heat source instead of the reactor in order to heat helium gas up to 880degC (4MPa) at the chemical reactor inlet which is the same temperature as the HTTR hydrogen production system. Fabrication of the test facility was completed in February in 2002, and seven cycle operations were carried out from March in 2002 to December in 2004. This report describes the structure and main specifications of the test facility. (author)

HIGH EFFICIENCY GENERATION OF HYDROGEN FUELS USING NUCLEAR POWER

Energy Technology Data Exchange (ETDEWEB)

BROWN,LC; BESENBRUCH,GE; LENTSCH,RD; SCHULTZ,KR; FUNK,JF; PICKARD,PS; MARSHALL,AC; SHOWALTER,SK

2003-06-01

fossil fuels has trace contaminants (primarily carbon monoxide) that are detrimental to precious metal catalyzed fuel cells, as is now recognized by many of the world's largest automobile companies. Thermochemical hydrogen will not contain carbon monoxide as an impurity at any level. Electrolysis, the alternative process for producing hydrogen using nuclear energy, suffers from thermodynamic inefficiencies in both the production of electricity and in electrolytic parts of the process. The efficiency of electrolysis (electricity to hydrogen) is currently about 80%. Electric power generation efficiency would have to exceed 65% (thermal to electrical) for the combined efficiency to exceed the 52% (thermal to hydrogen) calculated for one thermochemical cycle. Thermochemical water-splitting cycles have been studied, at various levels of effort, for the past 35 years. They were extensively studied in the late 70s and early 80s but have received little attention in the past 10 years, particularly in the U.S. While there is no question about the technical feasibility and the potential for high efficiency, cycles with proven low cost and high efficiency have yet to be developed commercially. Over 100 cycles have been proposed, but substantial research has been executed on only a few. This report describes work accomplished during a three-year project whose objective is to ''define an economically feasible concept for production of hydrogen, by nuclear means, using an advanced high temperature nuclear reactor as the energy source.'' The emphasis of the first phase was to evaluate thermochemical processes which offer the potential for efficient, cost-effective, large-scale production of hydrogen from water in which the primary energy input is high temperature heat from an advanced nuclear reactor and to select one (or, at most three) for further detailed consideration. During Phase 1, an exhaustive literature search was performed to locate all cycles

Life cycle assessment of hydrogen and power production by supercritical water reforming of glycerol

International Nuclear Information System (INIS)

Galera, S.; Gutiérrez Ortiz, F.J.

2015-01-01

Highlights: • The environmental performance of the supercritical water reforming (SCWR) of glycerol was assessed. • Biogenic CO 2 emissions allowed quantifying a realistic GHG inventory of 3.8 kg CO 2 -eq/kg H 2 . • The environmental profile of SCWR process was compared to those of other technologies. • A good environmental performance of H 2 and power production by SCWR of glycerol was obtained. - Abstract: The environmental performance of hydrogen and electricity production by supercritical water reforming (SCWR) of glycerol was evaluated following a Life Cycle Assessment (LCA) approach. The heat-integrated process was designed to be energy self-sufficient. Mass and energy balances needed for the study were performed using Aspen Plus 8.4, and the environmental assessment was carried out through SimaPro 8.0. CML 2000 was selected as the life cycle impact assessment method, considering as impact categories the global warming, ozone layer depletion, abiotic depletion, photochemical oxidant formation, eutrophication, acidification, and cumulative energy demand. A distinction between biogenic and fossil CO 2 emissions was done to quantify a more realistic GHG inventory of 3.77 kg CO 2 -eq per kg H 2 produced. Additionally, the environmental profile of SCWR process was compared to other H 2 production technologies such as steam methane reforming, carbon gasification, water electrolysis and dark fermentation among others. This way, it is shown that SCWR of glycerol allows reducing greenhouse gas emissions and obtaining a favorable positive life cycle energy balance, achieving a good environmental performance of H 2 and power production by SCWR of glycerol

Risk analysis of complex hydrogen infrastructures

DEFF Research Database (Denmark)

Markert, Frank; Marangon, Alessia; Carcassi, Marco

2015-01-01

Developing a future sustainable refuelling station network is the next important step to establish hydrogen as a fuel for vehicles and related services. Such stations will most likely be integrated in existing refuelling stations and result in multi-fuel storages with a variety of fuels being...... to improve the quality of biomass based fuels. Therefore, hydrogen supply and distribution chains will likely not only serve to fulfil the demands of refuelling, but may also be important for the wider electrical power and fuel industries. Based on an integrated hydrogen supply and distribution network...... assessment methodologies, and how functional models could support coherent risk and sustainability (Risk Assessment, Life Cycle Assessment /Life Cycle Costing) assessments, in order to find optimal solutions for the development of the infrastructure on a regional or national level....

Multiferroic behavior associated with an order-disorder hydrogen bonding transition in metal-organic frameworks (MOFs) with the perovskite ABX3 architecture.

Science.gov (United States)

Jain, Prashant; Ramachandran, Vasanth; Clark, Ronald J; Zhou, Hai Dong; Toby, Brian H; Dalal, Naresh S; Kroto, Harold W; Cheetham, Anthony K

2009-09-30

Multiferroic behavior in perovskite-related metal-organic frameworks of general formula [(CH(3))(2)NH(2)]M(HCOO)(3), where M = Mn, Fe, Co, and Ni, is reported. All four compounds exhibit paraelectric-antiferroelectric phase transition behavior in the temperature range 160-185 K (Mn: 185 K, Fe: 160 K; Co: 165 K; Ni: 180 K); this is associated with an order-disorder transition involving the hydrogen bonded dimethylammonium cations. On further cooling, the compounds become canted weak ferromagnets below 40 K. This research opens up a new class of multiferroics in which the electrical ordering is achieved by means of hydrogen bonding.

A study on the hydrogen behavior and its mitigation in the APR1400 containment during a severe accident

International Nuclear Information System (INIS)

Kim, Jong Tae; Hong, Seong Wan; Park, Rae Joon; Kim, Sang Baik

2005-02-01

During a hypothetical severe accident in a nuclear power plant (NPP), hydrogen is generated by the active reaction of fuel-cladding and steam in the reactor pressure vessel and released with steam into the containment. In this study, the analysis of the hydrogen and steam behavior during selected severe accidents in the APR1400 containment has been conducted by using the GASFLOW code. For the SBLOCA, hydrogen was accumulated in the containment dome region quickly when only PARSs were used. When the igniters were turned on, a standing flame was formed around a coolant pump and burnt most of the hydrogen blown-out. For the TLOFW accident, the flap-type pressure damper installed at the IRWST vents strongly affected the flow structure of the hydrogen. And by the steam-rich and oxygen starvation conditions in the IRWST, DDT is not likely to occur. For the SBO accident, dry hydrogen was release in the IRWST by the assumption of full condensation of the released steam in the IRWST water. In this case, the possibility of flame acceleration is high in the IRWST and annular compartment. In this study two design modifications were proposed in view of the hydrogen mitigation strategy and their effectiveness was evaluated by the GASFLOW analysis

The corrosion rate and the hydrogen absorption behavior of titanium under reducing condition-III. Research document

International Nuclear Information System (INIS)

Suzuki, H.; Taniguchi, N.; Kawakami, S.

2005-03-01

Titanium is one of the candidate materials for overpacks as a high corrosion resistance metal. At the initial stage of repository, oxidizing condition will be given around the overpack because oxygen will be brought from the ground. The oxygen will be consumed by the reaction with impurities in buffer material or corrosion of overpack, and reducing condition will be achieved around the overpack. With the changing of redox condition, the water reduction becomes to dominate the cathodic reaction accompanying hydrogen generation. Crevice corrosion and hydrogen embrittlement are main causes of the damage of long term integrity of titanium overpack. However, it is not known about the corrosion resistance and hydrogen absorption behavior of titanium under reduction condition. In this study, the completely sealed ampoule test and the immersion test of titanium in aqueous solution and bentonite was carried out. In order to obtain reliable data about the hydrogen generation rate and the ratio of hydrogen absorption in titanium. From the result of 3 years immersion tests, corrosion rate of titanium were estimated to be in the order of 10 -2 ∼10 -1 μm/y in the aqueous solution, and 10 -3 ∼10 -2 μm/y in bentonite. This value is almost the same as the last report. Almost all the hydrogen generated by corrosion was absorbed in titanium in the immersion tests in completely sealed ampoule. In the examination that changed each parameter, it was suggested that the amount of the hydrogen absorption become 2∼3 times in 1M HCO 3- and pH13. (author)

Energy pathway analysis - a hydrogen fuel cycle framework for system studies

International Nuclear Information System (INIS)

Badin, J.S.; Tagore, S.

1997-01-01

An analytical framework has been developed that can be used to estimate a range of life-cycle costs and impacts that result from the incremental production, storage, transport, and use of different fuels or energy carriers, such as hydrogen, electricity, natural gas, and gasoline. This information is used in a comparative analysis of energy pathways. The pathways provide the U.S. Department of Energy (DOE) with an indication of near-, mid-, and long-term technologies that have the greatest potential for advancement and can meet the cost goals. The methodology and conceptual issues are discussed. Also presented are results for selected pathways from the E3 (Energy, Economics, Emissions) Pathway Analysis Model. This model will be expanded to consider networks of pathways and to be compatible with a linear programming optimization processor. Scenarios and sets of constraints (energy demands, sources, emissions) will be defined so the effects on energy transformation activities included in the solution and on the total optimized system cost can be investigated. This evaluation will be used as a guide to eliminate technically feasible pathways if they are not cost effective or do not meet the threshold requirements for the market acceptance. (Author)

Nickel-hydrogen bipolar battery system

Science.gov (United States)

Thaller, L. H.

1982-01-01

Rechargeable nickel-hydrogen systems are described that more closely resemble a fuel cell system than a traditional nickel-cadmium battery pack. This was stimulated by the currently emerging requirements related to large manned and unmanned low Earth orbit applications. The resultant nickel-hydrogen battery system should have a number of features that would lead to improved reliability, reduced costs as well as superior energy density and cycle lives as compared to battery systems constructed from the current state-of-the-art nickel-hydrogen individual pressure vessel cells.

Hydrogen embrittlement and galvanic corrosion of titanium alloys

Energy Technology Data Exchange (ETDEWEB)

Soh, Jeong Ryong; Jeong, Y. H.; Choi, B. K.; Baek, J. H.; Hwang, D. Y.; Choi, B. S.; Lee, D. J

2000-06-01

The material properties including the fracture behavior of titanium alloys used as a steam generator tube in SMART can be degraded de to the hydrogen embrittlement and the galvanic corrosion occurring as a result of other materials in contact with titanium alloys in a conducting corrosive environment. In this report the general concepts and trends of hydrogen embrittlement are qualitatively described to adequately understand and expect the fracture behavior from hydrogen within the bulk of materials and under hydrogen containing environments because hydrogen embrittlement may be very complicated process. And the characteristics of galvanic corrosion closely related to hydrogen embrittlement is qualitatively based on wimple electrochemical theory.

Hydrogen embrittlement and galvanic corrosion of titanium alloys

International Nuclear Information System (INIS)

Soh, Jeong Ryong; Jeong, Y. H.; Choi, B. K.; Baek, J. H.; Hwang, D. Y.; Choi, B. S.; Lee, D. J.

2000-06-01

The material properties including the fracture behavior of titanium alloys used as a steam generator tube in SMART can be degraded de to the hydrogen embrittlement and the galvanic corrosion occurring as a result of other materials in contact with titanium alloys in a conducting corrosive environment. In this report the general concepts and trends of hydrogen embrittlement are qualitatively described to adequately understand and expect the fracture behavior from hydrogen within the bulk of materials and under hydrogen containing environments because hydrogen embrittlement may be very complicated process. And the characteristics of galvanic corrosion closely related to hydrogen embrittlement is qualitatively based on wimple electrochemical theory

Hydrogenation Behaviors of MgH{sub x}-Graphene Composites by Reactive Mechanical Grinding

Energy Technology Data Exchange (ETDEWEB)

Jang, Min-hyuk; Park, So-Hyun; Hong, Tae-Whan [Korea National University of Transportation, Chungju (Korea, Republic of)

2016-04-15

In order to mitigate the disadvantage of the Mg hydrides, several studies have been conducted that have used MgH{sub x} intermixed with carbon. Graphene is a kind of carbon allotrope that is easily subject to a desorption reaction at low temperatures because such a reaction is exothermic. In this work, an MgH{sub x}-graphene mixture has been prepared by reactive mechanical grinding. The synthesized powder was characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and simultaneous thermogravimetric (TG) and differential scanning calorimetric (DSC) analyses. The hydrogenation behaviors were evaluated using a Sievert’s type automatic pressure-composition-temperature (PCT) apparatus without activation treatment. From the characteristics of the absorption kinetics and the curves observed, the role of graphene as a catalyst in hydrogen absorption was determined. According to the results of the PCI curve, the available hydrogen storage amounts for MgH{sub x}-5 wt% graphene composites had maximum values of 3.69, 5.09, and 5.72 wt% at 423, 523, and 623 K, respectively. Those values for MgH{sub x}-10 wt% graphene were 5.08, 5.45, and 5.83 wt% at 423, 523, and 673K, respectively.

A Rechargeable Hydrogen Battery.

Science.gov (United States)

Christudas Dargily, Neethu; Thimmappa, Ravikumar; Manzoor Bhat, Zahid; Devendrachari, Mruthunjayachari Chattanahalli; Kottaichamy, Alagar Raja; Gautam, Manu; Shafi, Shahid Pottachola; Thotiyl, Musthafa Ottakam

2018-04-27

We utilize proton-coupled electron transfer in hydrogen storage molecules to unlock a rechargeable battery chemistry based on the cleanest chemical energy carrier molecule, hydrogen. Electrochemical, spectroscopic, and spectroelectrochemical analyses evidence the participation of protons during charge-discharge chemistry and extended cycling. In an era of anthropogenic global climate change and paramount pollution, a battery concept based on a virtually nonpolluting energy carrier molecule demonstrates distinct progress in the sustainable energy landscape.

Dimensional behavior of Ni-YSZ composites during redox cycling

DEFF Research Database (Denmark)

Pihlatie, Mikko; Kaiser, Andreas; Larsen, Peter Halvor

2009-01-01

The dimensional behavior of Ni-yttria-stabilized zirconia (YSZ) cermets during redox cycling was tested in dilatometry within the temperature range 600-1000 degrees C. The effect Of humidity oil redox stability was investigated at intermediate and low temperatures. We show that both the sintering...... of nickel depending on temperature of the initial reduction and the operating conditions, and the temperature of reoxidation are very important for the size of the dimensional change. Cumulative redox strain (CRS) is shown to be correlated with temperature. Measured maximum CRS after three redox cycles...... varies within 0.25-3.2% dL/L in dry gas and respective temperature range of 600-1000 degrees C. A high degree of redox reversibility was reached at low temperature. however. reversibility is lost at elevated temperatures. We found that at 850 degrees C, 6% steam and a very high p(H2O)/p(H2) ratio...

Life Cycle Greenhouse Gas Emissions of By-product Hydrogen from Chlor-Alkali Plants

Energy Technology Data Exchange (ETDEWEB)

Lee, Dong-Yeon [Argonne National Lab. (ANL), Argonne, IL (United States). Systems Assessment Group, Energy Systems Division; Elgowainy, Amgad A. [Argonne National Lab. (ANL), Argonne, IL (United States). Systems Assessment Group, Energy Systems Division; Dai, Qiang [Argonne National Lab. (ANL), Argonne, IL (United States). Systems Assessment Group, Energy Systems Division

2017-12-01

Current hydrogen production capacity in the U.S. is about 15.8 million tonne (or metric ton) per year (Brown 2016). Some of the hydrogen (2 million tonne) is combusted for its heating energy value, which makes total annual net production 13.8 million tonne (Table 1). If captive by-product hydrogen (3.3 million tonne) from catalytic reforming at oil refineries is excluded (Brown 2016; EIA 2008), approximately 11 million tonne is available from the conventional captive and merchant hydrogen market (DOE 2013). Captive hydrogen (owned by the refiner) is produced and consumed on site (e.g., process input at refineries), whereas merchant hydrogen is produced and sold as a commodity to external consumers. Whether it is merchant or captive, most hydrogen produced in the U.S. is on-purpose (not by-product)— around 10 million tonne/year.

The life cycle greenhouse gas emissions implications of power and hydrogen production for oil sands operations

International Nuclear Information System (INIS)

McKellar, J.M.; Bergerson, J.A.; MacLean, H.L.

2009-01-01

'Full text:' The Alberta Oil Sands represent a major economic opportunity for Canada, but the industry is also a significant source of greenhouse gas (GHG) emissions. One of the sources of these emissions is the use of natural gas for the production of electricity, steam and hydrogen. Due to concerns around resource availability and price volatility, there has been considerable discussion regarding the potential replacement of natural gas with an alternative fuel. While some of the options are non-fossil and could potentially reduce GHG emissions (e.g., nuclear, geothermal, biomass), others have the potential to increase emissions. A comparative life cycle assessment was completed to investigate the relative GHG emissions, energy consumption and financial implications of replacing natural gas with coal, coke, asphaltenes or bitumen for the supply of electricity, steam and hydrogen to oil sands operations. The potential use of carbon capture and storage (CCS) was also investigated as a means of reducing GHG emissions. Preliminary results indicate that, without CCS, the natural gas systems currently in use have lower life cycle GHG emissions than gasification systems using any of the alternative fuels analysed. However, when CCS is implemented in both the coke gasification and natural gas systems, the coke systems have lower GHG emissions and financial costs than the natural gas systems (assuming a 30-year project life and a natural gas price of 6.5 USD/gigajoule). The use of CCS does impose a financial penalty though, indicating that it is unlikely to be implemented without some financial incentive. While this study has limitations and uncertainties, the preliminary results indicate that although the GHG emissions of oil sands development pose a challenge to Canada, there are opportunities available for their abatement. (author)

Effect of coexistent hydrogen isotopes on tracer diffusion of tritium in alpha phase of group-V metal-hydrogen systems

International Nuclear Information System (INIS)

Sakamoto, Kan; Hashizume, Kenichi; Sugisaki, Masayasu

2009-01-01

Tracer diffusion coefficients of tritium in the alpha phase of group-V metal-hydrogen systems, α-MH(D)xTy (M=V and Ta; x>>y), were measured in order to clarify the effects of coexistent hydrogen isotopes on the tritium diffusion behavior. The hydrogen concentration dependence of such behavior and the effects of the coexistent hydrogen isotopes (protium and deuterium) were determined. The results obtained in the present (for V and Ta) and previous (for Nb) studies revealed that tritium diffusion was definitely dependent on hydrogen concentration but was not so sensitive to the kind of coexistent hydrogen isotopes. By summarizing those data, it was found that the hydrogen concentration dependence of the tracer diffusion coefficient of tritium in the alpha phase of group-V metals could be roughly expressed by a single empirical curve. (author)

Hydrogen storage alloy electrode and the nickel-hydrogen secondary battery using the electrode; Suiso kyuzo gokin denkyoku to sorewo mochiita nikkeru/suiso niji denchi

Energy Technology Data Exchange (ETDEWEB)

Ono, T. [Furukawa Electric Co. Ltd., Tokyo (Japan); Furukawa, J. [The Furukawa Battery Co. Ltd., Yokohama (Japan)

1997-02-14

With respect to the conventional nickel-hydrogen secondary battery, pulverization of the hydrogen storage alloy due to repetition of charging-discharging cycles can be prevented by using a fluorocarbon resin as a binder in manufacture of the hydrogen storage alloy electrode; however, the inner pressure increase of the battery in case of overcharging can not be fully controlled. The invention relates to control of the inner pressure increase of the nickel-hydrogen secondary battery in case of overcharging. As to the hydrogen storage alloy electrode, the compound comprising the hydrogen storage alloy powder as a main ingredient is supported by a current collector; further, the compound particularly comprises a fluororubber as a binder. The nickel-hydrogen secondary battery equipped with the hydrogen storage alloy electrode can control the inner pressure increase of the battery in case of overcharging, and lessen decrease of the battery capacity due to repetition of charging-discharging cycles over long time. The effects are dependent on the use of the fluororubber as a binder which has good flexibility, and strong binding capacity as well as water repellency. 1 tab.

Analysis of alternative flow sheets for the hybrid chlorine cycle

Energy Technology Data Exchange (ETDEWEB)

Gooding, Charles H. [Department of Chemical and Biomolecular Engineering, 209 Earle Hall, Clemson University, Clemson, SC 29634-0909 (United States)

2009-05-15

This paper reports the results of the most complete conceptual study conducted to date on hydrogen production using the hybrid chlorine cycle. Three alternative process flow sheets were developed, each capable of producing hydrogen at 35 C (308 K) and 21 bar. The alternative approaches differ primarily in the way HCl is isolated and converted to hydrogen and chlorine gases. Aspen Plus trademark simulation software was used to model the unit processes, supplemented where necessary by custom Excel spreadsheets. Major equipment was sized for a 200-million kg/yr plant; feasible materials of construction were identified; fixed capital investments and variable costs were estimated. Estimated net thermal efficiencies of the flow sheets range from 30% to 36%, based on the lower heating value of the hydrogen produced. With electrical power valued at $0.05/kWh, the cost of hydrogen produced by the hybrid chlorine cycle would be at least $3/kg. These results indicate that direct electrolysis of water is a more attractive way to produce hydrogen than any presently conceived version of the hybrid chlorine cycle. (author)

Evaluation of Nuclear Hydrogen Production System

International Nuclear Information System (INIS)

Park, Won Seok; Park, C. K.; Park, J. K. and others

2006-04-01

The major objective of this work is tow-fold: one is to develop a methodology to determine the best VHTR types for the nuclear hydrogen demonstration project and the other is to evaluate the various hydrogen production methods in terms of the technical feasibility and the effectiveness for the optimization of the nuclear hydrogen system. Both top-tier requirements and design requirements have been defined for the nuclear hydrogen system. For the determination of the VHTR type, a comparative study on the reference reactors, PBR and PBR, was conducted. Based on the analytic hierarchy process (AHP) method, a systematic methodology has been developed to compare the two VHTR types. Another scheme to determine the minimum reactor power was developed as well. Regarding the hydrogen production methods, comparison indices were defined and they were applied to the IS (Iodine-Sulfur) scheme, Westinghouse process, and the, high-temperature electrolysis method. For the HTE, IS, and MMI cycle, the thermal efficiency of hydrogen production were systematically evaluated. For the IS cycle, an overall process was identified and the functionality of some key components was identified. The economy of the nuclear hydrogen was evaluated, relative to various primary energy including natural gas coal, grid-electricity, and renewable. For the international collaborations, two joint research centers were established: NH-JRC between Korea and China and NH-JDC between Korea and US. Currently, several joint researches are underway through the research centers

High-cycle fatigue behavior of ultrafine-grained austenitic stainless and TWIP steels

Energy Technology Data Exchange (ETDEWEB)

Hamada, A.S. [Materials Engineering Laboratory (4KOMT), Box 4200, University of Oulu, 90014 Oulu (Finland); Metallurgical and Materials Engineering Department, Faculty of Petroleum and Mining Engineering, Suez Canal University, Box 43721, Suez (Egypt); Karjalainen, L.P., E-mail: pentti.karjalainen@oulu.fi [Materials Engineering Laboratory (4KOMT), Box 4200, University of Oulu, 90014 Oulu (Finland)

2010-08-20

High-cycle fatigue behavior of ultrafine-grained (UFG) 17Cr-7Ni Type 301LN austenitic stainless and high-Mn Fe-22Mn-0.6C TWIP steels were investigated in a reversed plane bending fatigue and compared to the behavior of steels with conventional coarse grain (CG) size. Optical, scanning and transmission electron microscopy were used to examine fatigue damage mechanisms. Testing showed that the fatigue limits leading to fatigue life beyond 4 x 10{sup 6} cycles were about 630 MPa for 301LN while being 560 MPa for TWIP steel, and being 0.59 and 0.5 of the tensile strength respectively. The CG counterparts were measured to have the fatigue limits of 350 and 400 MPa. The primary damage caused by fatigue took place by grain boundary cracking in UFG 301LN, while slip band cracking occurred in CG 301LN. However, in the case of TWIP steel, the fatigue damage mechanism is similar in spite of the grain size. In the course of cycling neither the formation of a martensite structure nor mechanical twinning occurs, but intense slip bands are created with extrusions and intrusions. Fatigue crack initiates preferentially on grain and twin boundaries, and especially in the intersection sites of slip bands and boundaries.

Hydrogen behavior at a subcomparment in the containment building

Energy Technology Data Exchange (ETDEWEB)

Lee, U J; Park, G C [Seoul National University, Seoul (Korea, Republic of)

1998-12-31

For hydrogen management in severe accidents with degraded nuclear core of PWR`s, several experiments have been performed in the SNU hydrogen mixing facility. The objectives are understanding the extent of hydrogen mixing and analyzing the effects of factors which dominate uniform or non-uniform mixing at compartments in the containment building. The facility represents on a 1/11th linearly scaled model of the YGN unit 3 and 4, hydrogen was simulated by helium. Because there are the gaps between safety injection tank and compartment layers in the containment, the test facility was constructed in three dimensional mode for analyzing of mixture behaviour through the gaps. >From the experimental results we could conclude that overall hydrogen concentration distributed uniformly in the free volume of the test compartment, but fluctuated in the gaps. This paper is focused on experimental result from several experiments. 5 refs., 4 figs. (Author)

Hydrogen behavior at a subcomparment in the containment building

Energy Technology Data Exchange (ETDEWEB)

Lee, U. J.; Park, G. C. [Seoul National University, Seoul (Korea, Republic of)

1997-12-31

For hydrogen management in severe accidents with degraded nuclear core of PWR`s, several experiments have been performed in the SNU hydrogen mixing facility. The objectives are understanding the extent of hydrogen mixing and analyzing the effects of factors which dominate uniform or non-uniform mixing at compartments in the containment building. The facility represents on a 1/11th linearly scaled model of the YGN unit 3 and 4, hydrogen was simulated by helium. Because there are the gaps between safety injection tank and compartment layers in the containment, the test facility was constructed in three dimensional mode for analyzing of mixture behaviour through the gaps. >From the experimental results we could conclude that overall hydrogen concentration distributed uniformly in the free volume of the test compartment, but fluctuated in the gaps. This paper is focused on experimental result from several experiments. 5 refs., 4 figs. (Author)

Effect of MoS2 on hydrogenation storage properties of LiBH4

International Nuclear Information System (INIS)

Liang, Dan; Han, Shumin; Wang, Jiasheng; Zhang, Wei; Zhao, Xin; Zhao, Ziyang

2014-01-01

The hydrogen storage properties of LiBH 4 ball milled with 20 wt% MoS 2 have been investigated. It shows that the LiBH 4 doped with MoS 2 exhibits favorable hydrogenation and dehydrogenation properties in terms of decomposition temperature and hydriding/dehydriding reversibility. The sample with MoS 2 starts to release hydrogen at 230 °C and has a decrease of 80 °C in contrast with pristine LiBH 4 . Furthermore, for the second cycle, the LiBH 4 with MoS 2 maintains a reversible hydrogen storage capacity of about 8.0 wt% which is almost identical with the first cycle under 5 MPa at 550 °C. Analyzed by the XRD and the FTIR results, LiBH 4 can be regenerated after re-hydrogenation under a relatively mild condition by adding MoS 2 . The improvement of the hydrogenation and dehydrogenation properties mainly results from the formation of Li 2 S and MoB 2 during ball milling. -- Graphical abstract: Hydrogen absorption curves of LiBH 4 doped with MoS 2 for five cycles at 400 °C. Highlights: • The hydrogen absorption capacity is nearly the same for 5 cycles at 400 °C. • The sample with MoS 2 starts to release hydrogen at 230 °C. • The coexistence of MoB 2 and Li 2 S catalyzes the decomposition of LiBH 4

Neutron time behavior for deuterium neutral beam injection into a hydrogen plasma in ORMAK

International Nuclear Information System (INIS)

England, A.C.; Howe, H.C.; Mihalczo, J.T.; Fowler, R.H.

1977-10-01

Neutrons were produced by D-D interactions when a 28-keV deuterium beam was coinjected into a hydrogen plasma in the Oak Ridge Tokamak (ORMAK). Fokker-Planck calculations, which correctly predict the time behavior of the neutron rate after beam turnon, show that the majority of the neutrons are from injected particles interacting with previously injected deuterons that have scattered to pitch angles of approximately 60 to 90 0 while slowing down

Hydrogen production from solar energy

Science.gov (United States)

Eisenstadt, M. M.; Cox, K. E.

1975-01-01

Three alternatives for hydrogen production from solar energy have been analyzed on both efficiency and economic grounds. The analysis shows that the alternative using solar energy followed by thermochemical decomposition of water to produce hydrogen is the optimum one. The other schemes considered were the direct conversion of solar energy to electricity by silicon cells and water electrolysis, and the use of solar energy to power a vapor cycle followed by electrical generation and electrolysis. The capital cost of hydrogen via the thermochemical alternative was estimated at $575/kW of hydrogen output or $3.15/million Btu. Although this cost appears high when compared with hydrogen from other primary energy sources or from fossil fuel, environmental and social costs which favor solar energy may prove this scheme feasible in the future.

Ammonium generation during SRAT cycle

International Nuclear Information System (INIS)

Hsu, C.W.

1992-01-01

During the IDMS noble-metal demonstration runs ammonium nitrate deposition was found in the vessel vent system of the feed preparation area. In the bench-scale experiments of studying the hydrogen generation during the sludge treatment cycle, ammonium ion production was also monitored. It was found that: During a simulation of the DWPF Cold Chemical Runs SRAT cycle no detectable amount of ammonium ions was generated when treating a non-noble-metal containing sludge simulant according to the nitric acid flowsheet. Ammonium ions were generated during the SRAT-SME cycle when treating the noble-metal containing sludge with either formic acid or nitric acid/late-washing PHA. This is due to the reaction between formic acid and nitrate catalyzed by the noble metals in the sludge simulant. Ammonium ion production closely followed the hydrogen evolution from the catalytic decomposition of formic acid. This report summarizes the results of the production of ammonia during the SRAT cycle

A microfabricated nickel-hydrogen battery using thick film printing techniques

Science.gov (United States)

Tam, Waiping G.; Wainright, Jesse S.

To utilize the distinctive cycle life and safety characteristics of the nickel-hydrogen chemistry while eliminating the high pressure limitations of conventional nickel-hydrogen cells, a microfabricated nickel-hydrogen battery using a low-pressure metal hydride for hydrogen storage is being developed for powering micro-electromechanical systems (MEMS) devices and for biomedical applications where the battery would be implanted within the body. Thick film printing techniques which are simple and low cost were used to fabricate this battery. Inks were developed for each of the different battery components, including the electrodes, current collectors and separator. SEM images on these printed components showed the desired characteristics for each. Positive electrode cycling tests were performed on the printed positive electrodes while cyclic voltammetry was used to characterize the printed negative electrodes. Consistent charge and discharge performance was observed during positive electrode cycling. Full cells with printed positive and negative assemblies were assembled and tested.

A microfabricated nickel-hydrogen battery using thick film printing techniques

Energy Technology Data Exchange (ETDEWEB)

Tam, Waiping G.; Wainright, Jesse S. [Department of Chemical Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States)

2007-02-25

To utilize the distinctive cycle life and safety characteristics of the nickel-hydrogen chemistry while eliminating the high pressure limitations of conventional nickel-hydrogen cells, a microfabricated nickel-hydrogen battery using a low-pressure metal hydride for hydrogen storage is being developed for powering micro-electromechanical systems (MEMS) devices and for biomedical applications where the battery would be implanted within the body. Thick film printing techniques which are simple and low cost were used to fabricate this battery. Inks were developed for each of the different battery components, including the electrodes, current collectors and separator. SEM images on these printed components showed the desired characteristics for each. Positive electrode cycling tests were performed on the printed positive electrodes while cyclic voltammetry was used to characterize the printed negative electrodes. Consistent charge and discharge performance was observed during positive electrode cycling. Full cells with printed positive and negative assemblies were assembled and tested. (author)

Electron-microscopy studies of NaAlH{sub 4} with TiF{sub 3} additive: hydrogen-cycling effects

Energy Technology Data Exchange (ETDEWEB)

Andrei, C.M.; Holmestad, R. [Norwegian University of Science and Technology, Department of Physics, Trondheim (Norway); Walmsley, J.C. [SINTEF Materials and Chemistry, Trondheim (Norway); Brinks, H.W.; Hauback, B.C. [Institute for Energy Technology, P.O. Box 40, Kjeller (Norway); Srinivasan, S.S.; Jensen, C.M. [University of Hawaii, Department of Chemistry, Honolulu, HI (United States)

2005-02-01

NaAlH{sub 4} is a promising candidate material for hydrogen storage. Ti additives are effective in reducing the reaction temperatures and improving kinetics. In this work, the microstructure of NaAlH{sub 4} with 2% TiF{sub 3} has been studied in different conditions using a combination of transmission electron microscopy and scanning electron microscopy, both with energy-dispersive spectroscopic X-ray analysis. The effect of the additive on particle and grain size was examined after the initial ball-milling process and after 15 cycles. The additive has an uneven distribution in the sample after ball milling. Selected-area diffraction and high-resolution imaging confirmed the presence of TiF{sub 3}. This phase accounts for most of the Ti in the material at this stage and showed limited mixing with the alanate. The grain size within particles for TiF{sub 3} is larger than for the alanate particles. Diffraction from the latter was dominated by metallic aluminium. After cycling, the TiF{sub 3} has decomposed and energy-dispersive spectroscopic X-ray analysis maps showed some combination of Ti with the alanate phase. There is no significant change in the measurable grain size of the Al-containing alanate particles between the ball-milled and the 15-cycled samples, but more cycles result in agglomeration of the material. (orig.)

High-temperature low cycle fatigue behavior of a gray cast iron

Energy Technology Data Exchange (ETDEWEB)

Fan, K.L., E-mail: 12klfan@tongji.edu.cn; He, G.Q.; She, M.; Liu, X.S.; Lu, Q.; Yang, Y.; Tian, D.D.; Shen, Y.

2014-12-15

The strain controlled low cycle fatigue properties of the studied gray cast iron for engine cylinder blocks were investigated. At the same total strain amplitude, the low cycle fatigue life of the studied material at 523 K was higher than that at 423 K. The fatigue behavior of the studied material was characterized as cyclic softening at any given total strain amplitude (0.12%–0.24%), which was attributed to fatigue crack initiation and propagation. Moreover, this material exhibited asymmetric hysteresis loops due to the presence of the graphite lamellas. Transmission electron microscopy analysis suggested that cyclic softening was also caused by the interactions of dislocations at 423 K, such as cell structure in ferrite, whereas cyclic softening was related to subgrain boundaries and dislocation climbing at 523 K. Micro-analysis of specimen fracture appearance was conducted in order to obtain the fracture characteristics and crack paths for different strain amplitudes. It showed that the higher the temperature, the rougher the crack face of the examined gray cast iron at the same total strain amplitude. Additionally, the microcracks were readily blunted during growth inside the pearlite matrix at 423 K, whereas the microcracks could easily pass through pearlite matrix along with deflection at 523 K. The results of fatigue experiments consistently showed that fatigue damage for the studied material at 423 K was lower than that at 523 K under any given total strain amplitude. - Highlights: • The low cycle fatigue behavior of the HT250 for engine cylinder blocks was investigated. • TEM investigations were conducted to explain the cyclic deformation response. • The low cycle fatigue cracks of HT250 GCI were studied by SEM. • The fatigue life of the examined material at 523 K is higher than that at 423 K.

78 FR 43870 - Hydrogen Energy California's Integrated Gasification Combined Cycle Project; Preliminary Staff...

Science.gov (United States)

2013-07-22

... DEPARTMENT OF ENERGY Notice of Availability Hydrogen Energy California's Integrated Gasification... Energy (DOE) announces the availability of the Hydrogen Energy California's Integrated Gasification... potential environmental impacts associated with the Hydrogen Energy California's (HECA) Integrated...

Ultimate refrigerating conditions, behavior turning and a thermodynamic analysis for absorption–compression hybrid refrigeration cycle

International Nuclear Information System (INIS)

Zheng Danxing; Meng Xuelin

2012-01-01

Highlights: ► Two novel fundamental concepts of the absorption refrigeration cycle were proposed. ► The interaction mechanism of compressor pressure increasing with other key-parameters was investigated. ► A set of optimal operating condition of hybrid refrigeration cycle was found. ► A simulation and investigation for R134a-DMF hybrid refrigeration cycle was performed. - Abstract: The absorption–compression hybrid refrigeration cycle has been considered as an effective approach to reduce the mechanical work consumption by using low-grade heat, such as solar energy. This work aims at studying the thermodynamic mechanism of the hybrid refrigeration cycle. Two fundamental concepts have been proposed, which are the ultimate refrigerating temperature (or the ultimate temperature lift) and the behavior turning. On the basis of that, the interaction mechanism of compressor pressure increasing with other key-parameters and the impact of compressor pressure increasing on the cycle performance have been investigated. The key-parameters include the concentration difference, the circulation ratio of working fluid, etc. The work points out that the hybrid refrigeration cycle performance varies with the change of compressor outlet pressure and depends on which one achieves dominance in the hybrid refrigeration cycle, the absorption sub-system or the compression sub-system. The behavior turning point during parameters changing corresponds to a maximum value of the heat powered coefficient of performance. In this case, the hybrid refrigeration cycle performance is optimal because the low-grade heat utilization is the most effective. In addition, to validate the theoretical analysis, a solar hybrid refrigeration cycle with R134a–DMF as working pair was simulated. The Peng–Robinson equation of state was adopted to calculate thermophysical properties when the reliability assessment of the prediction models on the available literature data of R134a–DMF system had been

Hydrogen Pathways: Updated Cost, Well-to-Wheels Energy Use, and Emissions for the Current Technology Status of Ten Hydrogen Production, Delivery, and Distribution Scenarios

Energy Technology Data Exchange (ETDEWEB)

Ramsden, T.; Ruth, M.; Diakov, V.; Laffen, M.; Timbario, T. A.

2013-03-01

This report describes a life-cycle assessment conducted by the National Renewable Energy Laboratory (NREL) of 10 hydrogen production, delivery, dispensing, and use pathways that were evaluated for cost, energy use, and greenhouse gas (GHG) emissions. This evaluation updates and expands on a previous assessment of seven pathways conducted in 2009. This study summarizes key results, parameters, and sensitivities to those parameters for the 10 hydrogen pathways, reporting on the levelized cost of hydrogen in 2007 U.S. dollars as well as life-cycle well-to-wheels energy use and GHG emissions associated with the pathways.

Thermodynamic analysis of the use a chemical heat pump to link a supercritical water-cooled nuclear reactor and a thermochemical water-splitting cycle for hydrogen production

International Nuclear Information System (INIS)

Granovskii, Mikhail; Dincer, Ibrahim; Rosen, Marc A.; Pioro, Igor

2008-01-01

Increases in the power generation efficiency of nuclear power plants (NPPs) are mainly limited by the permissible temperatures in nuclear reactors and the corresponding temperatures and pressures of the coolants in reactors. Coolant parameters are limited by the corrosion rates of materials and nuclear-reactor safety constraints. The advanced construction materials for the next generation of CANDU reactors, which employ supercritical water (SCW) as a coolant and heat carrier, permit improved 'steam' parameters (outlet temperatures up to 625degC and pressures of about 25 MPa). An increase in the temperature of steam allows it to be utilized in thermochemical water splitting cycles to produce hydrogen. These methods are considered by many to be among the most efficient ways to produce hydrogen from water and to have advantages over traditional low-temperature water electrolysis. However, even lower temperature water splitting cycles (Cu-Cl, UT-3, etc.) require an intensive heat supply at temperatures higher than 550-600degC. A sufficient increase in the heat transfer from the nuclear reactor to a thermochemical water splitting cycle, without jeopardizing nuclear reactor safety, might be effectively achieved by application of a heat pump, which increases the temperature of the heat supplied by virtue of a cyclic process driven by mechanical or electrical work. Here, a high-temperature chemical heat pump, which employs the reversible catalytic methane conversion reaction, is proposed. The reaction shift from exothermic to endothermic and back is achieved by a change of the steam concentration in the reaction mixture. This heat pump, coupled with the second steam cycle of a SCW nuclear power generation plant on one side and a thermochemical water splitting cycle on the other, increases the temperature of the 'nuclear' heat and, consequently, the intensity of heat transfer into the water splitting cycle. A comparative preliminary thermodynamic analysis is conducted of

Low cycle fatigue behavior of a ferritic reactor pressure vessel steel

Energy Technology Data Exchange (ETDEWEB)

Sarkar, Apu, E-mail: asarkar@barc.gov.in; Kumawat, Bhupendra K.; Chakravartty, J.K.

2015-07-15

The cyclic stress–strain response and the low cycle fatigue (LCF) behavior of 20MnMoNi55 pressure vessel steel were studied. Tensile strength and LCF properties were examined at room temperature (RT) using specimens cut from rolling direction of a rolled block. The fully reversed strain-controlled LCF tests were conducted at a constant total strain rate with different axial strain amplitude levels. The cyclic strain–stress relationships and the strain–life relationships were obtained through the test results, and related LCF parameters of the steel were calculated. The studied steel exhibits cyclic softening behavior. Furthermore, analysis of stabilized hysteresis loops showed that the steel exhibits non-Masing behavior. Complementary scanning electron microscopy examinations were also carried out on fracture surfaces to reveal dominant damage mechanisms during crack initiation, propagation and fracture. Multiple crack initiation sites were observed on the fracture surface. The investigated LCF behavior can provide reference for pressure vessel life assessment and fracture mechanisms analysis.

Thermochemical reactivity of 5–15 mol% Fe, Co, Ni, Mn-doped cerium oxides in two-step water-splitting cycle for solar hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Gokon, Nobuyuki, E-mail: ngokon@eng.niigata-u.ac.jp [Center for Transdisciplinary Research, Niigata University, 8050 Ikarashi 2-nocho, Nishi-ku, Niigata 950-2181 (Japan); Suda, Toshinori [Graduate School of Science and Technology, Niigata University, 8050 Ikarashi 2-nocho, Niigata 950-2181 (Japan); Kodama, Tatsuya [Department of Chemistry & Chemical Engineering, Faculty of Engineering, Niigata University, 8050 Ikarashi 2-nocho, Niigata 950-2181 (Japan)

2015-10-10

Highlights: • 5–15 mol% M-doped ceria are examined for thermochemical two-step water-splitting. • 5 mol% Fe- and Co-doped ceria have stoichiometric production of oxygen and hydrogen. • 10–15 mol% Fe- and Mn-doped ceria showed near-stoichiometric production. - Abstract: The thermochemical two-step water-splitting cycle using transition element-doped cerium oxide (M–CeO{sub 2−δ}; M = Fe, Co, Ni, Mn) powders was studied for hydrogen production from water. The oxygen/hydrogen productivity and repeatability of M–CeO{sub 2−δ} materials with M doping contents in the 5–15 mol% range were examined using a thermal reduction (TR) temperature of 1500 °C and water decomposition (WD) temperatures in the 800–1150 °C range. The temperature, steam partial pressure, and steam flow rate in the WD step had an impact on the hydrogen productivity and production rate. 5 mol% Fe- and Co-doped CeO{sub 2−δ} enhances hydrogen productivity by up to 25% on average compared to undoped CeO{sub 2}, and shows stable repeatability of stoichiometric oxygen and hydrogen production for the cyclic thermochemical two-step water-splitting reaction. In addition, 5 mol% Mn-doped CeO{sub 2−δ}, 10 and 15 mol% Fe- and Mn-doped CeO{sub 2−δ} show near stoichiometric reactivities.

Proceedings of the DOE chemical energy storage and hydrogen energy systems contracts review

Energy Technology Data Exchange (ETDEWEB)

1980-02-01

Sessions were held on electrolysis-based hydrogen storage systems, hydrogen production, hydrogen storage systems, hydrogen storage materials, end-use applications and system studies, chemical heat pump/chemical energy storage systems, systems studies and assessment, thermochemical hydrogen production cycles, advanced production concepts, and containment materials. (LHK)

Hydrogenated amorphous silicon thin film anode for proton conducting batteries

Science.gov (United States)

Meng, Tiejun; Young, Kwo; Beglau, David; Yan, Shuli; Zeng, Peng; Cheng, Mark Ming-Cheng

2016-01-01

Hydrogenated amorphous Si (a-Si:H) thin films deposited by chemical vapor deposition were used as anode in a non-conventional nickel metal hydride battery using a proton-conducting ionic liquid based non-aqueous electrolyte instead of alkaline solution for the first time, which showed a high specific discharge capacity of 1418 mAh g-1 for the 38th cycle and retained 707 mAh g-1 after 500 cycles. A maximum discharge capacity of 3635 mAh g-1 was obtained at a lower discharge rate, 510 mA g-1. This electrochemical discharge capacity is equivalent to about 3.8 hydrogen atoms stored in each silicon atom. Cyclic voltammogram showed an improved stability 300 mV below the hydrogen evolution potential. Both Raman spectroscopy and Fourier transform infrared spectroscopy studies showed no difference to the pre-existing covalent Si-H bond after electrochemical cycling and charging, indicating a non-covalent nature of the Si-H bonding contributing to the reversible hydrogen storage of the current material. Another a-Si:H thin film was prepared by an rf-sputtering deposition followed by an ex-situ hydrogenation, which showed a discharge capacity of 2377 mAh g-1.

Hydrogen Embrittlement

Science.gov (United States)

Woods, Stephen; Lee, Jonathan A.

2016-01-01

hydrogen embrittlement. The effects of hydrogen gas on mechanical properties such as tensile strength, ductility, fracture, low and high cycle fatigue, crack growth rate, and creep rupture are analyzed with respect to the general trends established from the HEE index values. It is observed that the severity of HE effects is also influenced by environmental factors such as pressure, temperature, and hydrogen gas purity. The severity of HE effects is also influenced by material factors such as surface finish, heat treatment, and product forms, compositions, grain direction, and crystal orientations.

TEM analysis of the microstructure in TiF3-catalyzed and pure MgH2 during the hydrogen storage cycling

International Nuclear Information System (INIS)

Danaie, Mohsen; Mitlin, David

2012-01-01

We utilized transmission electron microscopy (TEM) analysis, with a cryogenically cooled sample stage, to detail the microstructure of partially transformed pure and titanium fluoride-catalyzed magnesium hydride powder during hydrogenation cycling. The TiF 3 -catalyzed MgH 2 powder demonstrated excellent hydrogen storage kinetics at various temperatures, whereas the uncatalyzed MgH 2 showed significant degradation in both kinetics and capacity. TEM analysis on the partially hydrogen absorbed and partially desorbed pure Mg(MgH 2 ) revealed a large fraction of particles that were either not transformed at all or were completely transformed. On the other hand, in the MgH 2 +TiF 3 system it was much easier to identify regions with both the hydride and the metal phase coexisting in the same particle. This enabled us to establish the metal hydride orientation relationship (OR) during hydrogen absorption. The OR was determined to be (1 1 0)MgH 2 || (−1 1 0 −1)Mg and [−1 1 1]MgH 2 || [0 1 −1 1]Mg. During absorption the number density of the hydride nuclei does not show a dramatic increase due the presence of TiF 3 . Conversely, during desorption the TiF 3 catalyst substantially increases the number of the newly formed Mg crystallites, which display a strong texture correlation with respect to the parent MgH 2 phase. Titanium fluoride also promotes extensive twinning in the hydride phase.

Hydrogen and water reactor safety: proceedings

International Nuclear Information System (INIS)

1982-01-01

Separate abstracts were prepared for papers presented in the following areas of interest: 1) hydrogen research programs; 2) hydrogen behavior during light water reactor accidents; 3) combustible gas generation; 4) hydrogen transport and mixing; 5) combustion modeling and experiments; 6) accelerated flames and detonations; 7) combustion mitigation and control; and 8) equipment survivability

Hydrogen and water reactor safety: proceedings

Energy Technology Data Exchange (ETDEWEB)

1982-01-01

Separate abstracts were prepared for papers presented in the following areas of interest: 1) hydrogen research programs; 2) hydrogen behavior during light water reactor accidents; 3) combustible gas generation; 4) hydrogen transport and mixing; 5) combustion modeling and experiments; 6) accelerated flames and detonations; 7) combustion mitigation and control; and 8) equipment survivability.

Effects of high mean stress on the high-cycle fatigue behavior of PWA 1480

International Nuclear Information System (INIS)

Majumdar, S.; Antolovich, S.; Milligan, W.

1985-03-01

PWA 1480 is a potential candidate material for use in the high-pressure fuel turbine blade of the Space Shuttle Main Engine. As an engine material it will be subjected to high-cycle fatigue loading superimposed on a high mean stress due to combined centrifugal and thermal loadings. This paper describes results obtained in an ongoing program to determine the effects of a high mean stress on the high-cycle fatigue behavior of this material

Numerical Methods for an Analysis of Hydrogen Behaviors Coupled with Thermal Hydraulics in a NPP Containment

International Nuclear Information System (INIS)

Kim, Jongtae; Park, Rae-Joon; Hong, Seong-Wan; Kim, Gun-Hong

2016-01-01

In a containment safety analysis, multi-dimensional characteristics in thermal hydraulics are very important because the flow paths are not confined in a large free volume of the containment. The analysis is difficult because of a difference in length scales between a characteristic length of the flow and representative length of the containment. In order to simulate hydrogen and steam behaviors in a containment during postulated severe accidents, the GASFLOW code as a multi-dimensional analysis tool for NPP containment has been used for years because of its computational efficiency. Though GASFLOW is well developed for a real NPP containment analysis, there exist shortcomings in nodalization, two-phase and turbulence models. It is based on a Cartesian or cylindrical coordinate mesh, so it is impractical to refine a mesh locally in a region with a physical or geometrical complication. In this paper, the importance of the hydrogen safety in an NPP containment and requirements of the analysis tool was described. And physical models necessary for the hydrogen safety analysis code were listed. As a member of international collaborative project HYMERES for containment thermal hydraulics, KAERI is actively participating in an analytic working group. As an analysis tool for blind benchmarkes, the analysis code described in this paper was used. From the blind benchmark analyses, it was found that the code is very promising for hydrogen safety analysis. Currently, it is proposed to develop the code collaboratively in a hydrogen safety community based on an open-source strategy

Numerical Methods for an Analysis of Hydrogen Behaviors Coupled with Thermal Hydraulics in a NPP Containment

Energy Technology Data Exchange (ETDEWEB)

Kim, Jongtae; Park, Rae-Joon; Hong, Seong-Wan; Kim, Gun-Hong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

In a containment safety analysis, multi-dimensional characteristics in thermal hydraulics are very important because the flow paths are not confined in a large free volume of the containment. The analysis is difficult because of a difference in length scales between a characteristic length of the flow and representative length of the containment. In order to simulate hydrogen and steam behaviors in a containment during postulated severe accidents, the GASFLOW code as a multi-dimensional analysis tool for NPP containment has been used for years because of its computational efficiency. Though GASFLOW is well developed for a real NPP containment analysis, there exist shortcomings in nodalization, two-phase and turbulence models. It is based on a Cartesian or cylindrical coordinate mesh, so it is impractical to refine a mesh locally in a region with a physical or geometrical complication. In this paper, the importance of the hydrogen safety in an NPP containment and requirements of the analysis tool was described. And physical models necessary for the hydrogen safety analysis code were listed. As a member of international collaborative project HYMERES for containment thermal hydraulics, KAERI is actively participating in an analytic working group. As an analysis tool for blind benchmarkes, the analysis code described in this paper was used. From the blind benchmark analyses, it was found that the code is very promising for hydrogen safety analysis. Currently, it is proposed to develop the code collaboratively in a hydrogen safety community based on an open-source strategy.

Large-field behavior of the LoSurdo-Stark resonances in atomic hydrogen

Energy Technology Data Exchange (ETDEWEB)

Alvarez, G. (Departamento de Fisica Teorica, Facultad de Ciencias Fisicas, Universidad Complutense, 28040 Madrid (Spain)); Silverstone, H.J. (Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218 (United States))

1994-12-01

The Schroedinger equation for atomic hydrogen in a large electric field [ital F] is solved by separation in parabolic coordinates. As [ital F][r arrow][infinity], the scaled field [ital f] that enters the separated equations tends to 0. Thus the large-[ital F] asymptotics depend on the small-[ital f] behavior of the separated equations, each of which in turn is equivalent to a quarticly perturbed two-dimensional anharmonic oscillator. The Bender-Wu branch cuts of the oscillator play a major role in the hydrogen asymptotics. A simple iterative algorithm permits the calculation of the branch points at which two eigenvalues coincide. We have found numerically that, as [ital F][r arrow][infinity], the separation constant [beta][sub 1] returns to the smaller of the unperturbed values [beta][sub 1][sup (0)] or [beta][sub 2][sup (0)]. At the same time, [beta][sub 2] tends to the negative of the smaller value. As the real electric field [ital F] increases from 0 to [infinity], in each case that [beta][sub 1][sup (0)] and [beta][sub 2][sup (0)] are not equal, the trajectory of either [ital f] or [ital e][sup [minus][ital i][pi

Evidence from data storage tags for the presence of lunar and semilunar behavioral cycles in spawning Atlantic cod

Science.gov (United States)

Grabowski, Timothy B.; McAdam, Bruce J.; Thorsteinsson, Vilhjalmur; Marteinsdóttir, Gudrún

2015-01-01

Understanding the environmental processes determining the timing and success of reproduction is of critical importance to developing effective management strategies of marine fishes. Unfortunately it has proven difficult to comprehensively study the reproductive behavior of broadcast-spawning fishes. The use of electronic data storage tags (DSTs) has the potential to provide insights into the behavior of fishes. These tags allow for data collection over relatively large spatial and temporal scales that can be correlated to predicted environmental conditions and ultimately be used to refine predictions of year class strength. In this paper we present data retrieved from DSTs demonstrating that events putatively identified as Atlantic cod spawning behavior is tied to a lunar cycle with a pronounced semi-lunar cycle within it. Peak activity occurs around the full and new moon with no evidence of relationship with day/night cycles.

Contribution of the low cycle fatigue on ultra high purity Ni-Cr-Fe alloys and on Ni monocrystals to the understanding of the hydrogen role in stress corrosion cracking for the alloys 600 and 690

International Nuclear Information System (INIS)

Renaudot, N.

1999-06-01

We discuss the role of hydrogen in cracking of Ni base alloys used for pressurised water reactor (PWR) primary tubes (alloy 600 and 690). Cracking can be explained by a Stress Corrosion Cracking (SCC) phenomenon. For this purpose, Low cycle fatigue (R = - 1) under cathodic charging at room temperature is conducted to study hydrogen effects on propagation of cracks mechanically initiated by the formation of Persistent Slip Bands (PSB). Low cycle fatigue on Ultra High Purity specimens (Ni, alloy 600 and 690) reveals the very important hydrogen effect on crack propagation rate, whatever the Cr content in the Ni base alloy. If Cr seems to have an effect over-hydrogen penetration in specimens (by a protective film formation), it have no beneficial effect when hydrogen have diffused ahead of a crack tip. Propagation rates (transgranular or intergranular) are highly increased, no matter of the absence of impurities like sulphur. Then, in PWR, the difference in the behaviour of alloy 600 and 690 could be due to a slower microcrack propagation rate for alloy 690. Protective films could play an important role in this difference, which is to study. Low cycle fatigue on Ni single crystals oriented for single slip shows, for the first time on bulk specimen, a macroscopic softening which can be explained. by hydrogen-dislocation interactions. Moreover, a simple quantitative model based on these interactions results in the same softening as the one observed experimentally. These results allow to validate experimentally one of the most important steps in the 'Corrosion Enhanced Plasticity (CEP) model', i.e. the softening ahead of a stress corrosion crack tip by hydrogen dislocation interactions. This is of importance because this model can explain cracking in numerous FCC materials-environment couple. (author)

Influence of hydrogen reduction on photoelectro-chemical behavior of anodic oxidized n-TiO2 layers

Energy Technology Data Exchange (ETDEWEB)

Hartig, K J; Getoff, N

1983-07-01

The behavior of polycrystalline n-TiO2 photoanodes produced by anodic oxidation of Ti metal foils and subsequently reduced in hydrogen atmosphere at various temperatures and different times was investigated. The employed methods for their characterization were: scanning electron microscopy, X-ray diffraction, thickness determination, open-circuit voltage and capacitance/voltage studies as well as photoelectrochemical measurements. The reduction process results in an increase of oxygen deficiencies and a decrease of the amount of recombination centers and of grain-boundary energy barriers between the crystallites. All these parameters lead to a significant increase of the photoefficiency. The best photoanodes were obtained when the anodically oxidized samples were reduced under hydrogen at 800-850 C for 15 min (conversion of anatase to rutile crystal structures). 17 references.

Positron Spectroscopy of Nanodiamonds after Hydrogen Sorption

Directory of Open Access Journals (Sweden)

Lyudmila Nikitina

2018-01-01

Full Text Available The structure and defects of nanodiamonds influence the hydrogen sorption capacity. Positronium can be used as a sensor for detecting places with the most efficient capture of hydrogen atoms. Hydrogenation of carbon materials was performed from gas atmosphere. The concentration of hydrogen absorbed by the sample depends on the temperature and pressure. The concentration 1.2 wt % is achieved at the temperature of 243 K and the pressure of 0.6 MPa. The hydrogen saturation of nanodiamonds changes the positron lifetime. Increase of sorption cycle numbers effects the positron lifetime, as well as the parameters of the Doppler broadening of annihilation line. The electron-positron annihilation being a sensitive method, it allows detecting the electron density fluctuation of the carbon material after hydrogen saturation.

Hydrogenation and high temperature oxidation of Zirconium claddings

International Nuclear Information System (INIS)

Novotny, T.; Perez-Feró, E.; Horváth, M.

2015-01-01

In the last few years a new series of experiments started for supporting the new LOCA criteria, considering the proposals of US NRC. The effects which can cause the embrittlement of VVER fuel claddings were reviewed and evaluated in the framework of the project. The purpose of the work was to determine how the fuel cladding’s hydrogen uptake under normal operating conditions, effect the behavior of the cladding under LOCA conditions. As a first step a gas system equipment with gas valves and pressure gauge was built, in which the zirconium alloy can absorb hydrogen under controlled conditions. In this apparatus E110 (produced by electrolytic method, currently used at Paks NPP) and E110G (produced by a new technology) alloys were hydrogenated to predetermined hydrogen contents. According the results of ring compression tests the E110G alloys lose their ductility above 3200 ppm hydrogen content. This limit can be applied to determine the ductile-brittle transition of the nuclear fuel claddings. After the hydrogenation, high temperature oxidation experiments were carried out on the E110G and E110 samples at 1000 °C and 1200 °C. 16 pieces of E110G and 8 samples of E110 with 300 ppm and 600 ppm hydrogen content were tested. The oxidation of the specimens was performed in steam, under isothermal conditions. Based on the ring compression tests load-displacement curves were recorded. The main objective of the compression tests was to determine the ductile-brittle transition. These results were compared to the results of our previous experiments where the samples did not contain hydrogen. The original claddings showed more ductile behavior than the samples with hydrogen content. The higher hydrogen content resulted in a more brittle mechanical behavior. However no significant difference was observed in the oxidation kinetics of the same cladding types with different hydrogen content. The experiments showed that the normal operating hydrogen uptake of the fuel claddings

Hydrogen-absorbing alloys for the nickel-metal hydride battery

Energy Technology Data Exchange (ETDEWEB)

Mingming Geng; Jianwen Han; Feng Feng [University of Windsor, Ontario (Canada). Mechanical and Materials Engineering; Northwood, D.O. [University of Windsor, Ontario (Canada). Mechanical and Materials Engineering]|[Ryerson Polytechnic University, Toronto (Canada)

1998-12-31

In recent years, owing to the rapid development of portable electronic and electrical appliances, the market for rechargeable batteries has increased at a high rate. The nickel-metal hydride battery (Ni/MH) is one of the more promising types, because of its high capacity, high-rate charge/discharge capability and non-polluting nature. This type of battery uses a hydrogen storage alloy as its negative electrode. The characteristics of the Ni/MH battery, including discharge voltage, high-rate discharge capability and charge/discharge cycle lifetime are mainly determined by the construction of the negative electrode and the composition of the hydrogen-absorbing alloy. The negative electrode of the Ni/MH battery described in this paper was made from a mixture of hydrogen-absorbing alloy, nickel powder and polytetrafluoroethylene (PTFE). A multicomponent MmNi{sub 5}-based alloy (Mm{sub 0.95}Ti{sub 0.05}Ni{sub 3.85} Co{sub 0.45}Mn{sub 0.35}Al{sub 0.35}) was used as the hydrogen-absorbing alloy. The discharge characteristics of the negative electrode, including discharge capacity, cycle lifetime, and polarization overpotential, were studied by means of electrochemical experiments and analysis. The decay of the discharge capacity for the Ni/MH battery (AA size, 1 Ah) was about 1% after 100 charge/discharge cycles and 10% after 500 charge/discharge cycles. (author)

Effects of the estrous cycle and ovarian hormones on behavioral indices of anxiety in female rats.

Science.gov (United States)

Mora, S; Dussaubat, N; Díaz-Véliz, G

1996-10-01

The influence of the estrous cycle and the effects of exogenous administration of estradiol and progesterone on level of anxiety were studied in intact and ovariectomized rats. Intact Sprague-Dawley female rats were classified according to the stages of estrous cycle. Another group of rats was ovariectomized bilaterally and, 14 days after surgery, they received estradiol benzoate (10 micrograms/kg, s.c.) and/or progesterone (25 mg/kg, s.c.) or corn oil (1 ml/kg). The behavioral tests began 3 h after estradiol or 6 h after progesterone and consisted of: (1) exploration of an elevated plus-maze; and (2) retention of a passive avoidance response. Open-arm exploration of the plus-maze varied according to light intensity and the stages of the estrous cycle. There was a slight increase in open-arm exploration by rats in metestrus, under high light intensity. Low light intensity increased the exploration of the open arms by rats in proestrus and estrus, compared to the other phases of the cycle. Retention of the passive avoidance response was inhibited during proestrus and estrus. Progesterone increased open-arm exploration of the plus-maze under high light conditions, whereas estradiol antagonized this effect. Retention of passive avoidance was inhibited after estradiol or progesterone injection. These results suggest that the behavioral indices of anxiety can vary across the estrous cycle, that low light intensities have anxiolytic-like effects, and that the sensitivity to this effect is higher during proestrus and estrus. This could be explained through modulatory effects of ovarian hormones upon behavioral indices of anxiety.

Corrosion behavior of construction materials for ionic liquid hydrogen compressor

DEFF Research Database (Denmark)

Arjomand Kermani, Nasrin; Petrushina, Irina; Nikiforov, Aleksey Valerievich

2016-01-01

The corrosion behavior of various commercially available stainless steels and nickel-based alloys as possible construction materials for components which are in direct contact with one of five different ionic liquids was evaluated. The ionic liquids, namely: 1-ethyl-3-methylimidazolium triflate, 1...... liquid hydrogen compressor. An electrochemical cell was specially designed, and steady-state cyclic voltammetry was used to measure the corrosion resistance of the alloys in the ionic liquids at 23 °C, under atmospheric pressure. The results showed a very high corrosion resistance and high stability...... for all the alloys tested. The two stainless steels, AISI 316L and AISI 347 showed higher corrosion resistance compared to AISI 321 in all the ionic liquids tested. It was observed that small addition of molybdenum, tantalum, and niobium to the alloys increased the corrosion stability in the ionic liquids...

Advantages of the use of hydrogen fuel as compared to kerosene

International Nuclear Information System (INIS)

Koroneos, C.; Dompros, A.; Roumbas, G.; Moussiopoulos, N.

2005-01-01

A life cycle assessment (LCA) study has been carried out to investigate the environmental aspects of two types of aviation fuel, kerosene that is presently used and hydrogen. Hydrogen is selected as a future aircraft fuel because of the absence of CO 2 emissions from its use, its high energy content and its combustion kinetics. The life cycle of aviation fuel includes the production and the use of the aviation fuel in different types of aircraft. Hydrogen production by natural gas steam reforming and production upon renewable energy sources (RES) are examined. A very large number of environmental burdens result from the operation of the different fuel cycles. Air pollution is by far the biggest environmental problem that is resulting from hydrogen and kerosene production and use. This work has been mainly concentrated with this environmental impact category. It is shown that the production of hydrogen from RES has significantly lower environmental impact as compared to that of kerosene. However, the use of different RES carries different environmental impacts among them. The production of hydrogen resulting from the use of photovoltaics to capture solar energy carries the biggest environmental impact among the other RES, wind, hydropower, biomass and solar thermal

Membrane pumping technology, helium and hydrogen isotopes separation in the fusion hydrogen

International Nuclear Information System (INIS)

Pigarov, A.Yu.; Pistunovich, V.I.; Busnyuk, A.O.

1994-01-01

A gas pumping system for the ITER, improved by implementation of superpermeable membranes for selective hydrogen isotope exhaust, is considered. The study of the pumping capability of a niobium membrane for a hydrogen-helium mixture has been fulfilled. The membrane superpermeability can be only realized for atomic hydrogen. Helium does not pass through the membrane, and its presence does not affect the hydrogen pumping. A detailed Monte Carlo simulation of gas behavior for the experimental facility has been done. The probability of permeation for a hydrogen atom for one collision with the membrane is ∼0.1; the same probability of molecule permeation is ∼10 -5 . The probability for atomization, i.e. re-emission of an atomizer is ∼0.2; the probability of recombination of an atom is ∼0.2

Stability and Behaviors of Methane/Propane and Hydrogen Micro Flames

Science.gov (United States)

Yoshimoto, Takamitsu; Kinoshita, Koichiro; Kitamura, Hideki; Tanigawa, Ryoichi

The flame stability limits essentially define the fundamental operation of the combustion system. Recently the micro diffusion flame has been remarked. The critical conditions of the flame stability limit are highly dependent on nozzle diameter, species of fuel and so on. The micro diffusion flame of Methane/Propane and Hydrogen is formed by using the micro-scale nozzle of which inner diameter is less than 1mm. The configurations and behaviors of the flame are observed directly and visualized by the high speed video camera The criteria of stability limits are proposed for the micro diffusion flame. The objectives of the present study are to get further understanding of lifting/blow-off for the micro diffusion flame. The results obtained are as follows. (1) The behaviors of the flames are classified into some regions for each diffusion flame. (2) The micro diffusion flame of Methane/Propane cannot be sustained, when the nozzle diameter is less than 0.14 mm. (3) The diffusion flame cannot be sustained below the critical fuel flow rate. (4) The minimum flow which is formed does not depends on the average jet velocity, but on the fuel flow rate. (5) the micro flame is laminar. The flame length is decided by fuel flow rate.

Effect of heating on the behaviors of hydrogen in C-TiC films with auger electron spectroscopy and secondary ion mass spectroscopy analyses

International Nuclear Information System (INIS)

Zou, Y.; Wang, L.W.; Huang, N.K.

2007-01-01

C-TiC films with a content of 75% TiC were prepared with magnetron sputtering deposition followed by Ar + ion bombardment. Effect of heating on the behaviors of hydrogen in C-TiC films before and after heating was studied with Auger Electron Spectroscopy and Secondary Ion Mass Spectroscopy (SIMS) analyses. SIMS depth profiles of hydrogen after H + ion implantation and thermal treatment show different hydrogen concentrations in C-TiC coatings and stainless steel. SIMS measurements show the existence of TiH, TiH 2 , CH 3 , CH 4 , C 2 H 2 bonds in the films after H + ion irradiation and the changes in the Ti LMM, Ti LMV and C KLL Auger line shape reveal that they have a good hydrogen retention ability after heating up to the temperature 393 K. All the results show that C-TiC coatings can be used as a hydrogen retainer or hydrogen permeable barrier on stainless steel to protect it from hydrogen brittleness

Motor behavior during the first chewing cycle in subjects with fixed tooth- or implant-supported prostheses.

Science.gov (United States)

Grigoriadis, Joannis; Trulsson, Mats; Svensson, Krister G

2016-04-01

Appropriate sensory information from periodontal mechanoreceptors (PMRs) is important for optimizing the positioning of food and adjustment of force vectors during precision biting. This study was designed to describe motor behavior during the first cycle of a natural chewing task and to evaluate the role of such sensory input in this behavior. While 10 subjects with natural dentition, 11 with bimaxillary fixed tooth-supported prostheses (TSP) and 10 with bimaxillary fixed implant-supported prostheses (ISP) (mean age 69 [range 61-83]) chewed a total of five hazelnuts, their vertical and lateral jaw movements were recorded. Data obtained during the first chewing cycle of each hazelnut were analyzed. The amplitude of vertical and lateral mandibular movement and duration of jaw opening did not differ between the groups, indicating similar behavior during this part of the chewing cycle. However, only 30% of the subjects in the natural dentate group, but 82% of those in the TSP and 70% in the ISP group exhibited slippage of the hazelnut during jaw closure in at least one of five trials. The TSP and ISP groups also exhibited more irregular and narrower patterns of motion (total lateral/vertical movement = 0.15 and 0.19, respectively, compared to 0.27 for the natural group). Subjects with fixed tooth- or implant-supported prostheses in both jaws show altered behavior, including inadequate control of the hazelnut, during the first chewing cycle. We propose that these differences are due to impairment or absence of sensory signaling from PMRs in these individuals. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Processes of hydrogen production, coupled with nuclear reactors: Economic perspectives

International Nuclear Information System (INIS)

Werkoff, Francois; Avril, Sophie; Mansilla, Christine; Sigurvinsson, Jon

2006-01-01

Hydrogen production, using nuclear power is considered from a technic-economic (TE) point of view. Three different processes are examined: Alkaline electrolysis, High-temperature steam electrolysis (HTE) and the thermochemical Sulphur-Iodine (S/I) cycle. The three processes differ, in the sense that the first one is operational and both last ones are still at demonstration stages. For them, it is at present only possible to identify key points and limits of competitiveness. The cost of producing hydrogen by alkaline electrolysis is analysed. Three major contributions to the production costs are examined: the electricity consumption, the operation and maintenance expenditures and the depreciation capital expenditures. A technic-economic evaluation of hydrogen production by HTE coupled to a high-temperature reactor (HTR) is presented. Key points appear to be the electrolyser and the high temperature heat exchangers. The S/I thermochemical cycle is based on the decomposition and the re-composition of H 2 SO 4 and HI acids. The energy consumption and the recovery of iodine are key points of the S/I cycle. With the hypothesis that the hydrogen energy will progressively replace the fossil fuels, we give a first estimate of the numbers of nuclear reactors (EPR or HTR) that would be needed for a massive nuclear hydrogen production. (authors)

KOH concentration effect on cycle life of nickel-hydrogen cells

Science.gov (United States)

Lim, Hong S.; Verzwyvelt, S. A.

1987-01-01

A cycle life test of Ni/H2 cells containing electrolytes of various KOH concentrations and a sintered type nickel electrode was carried out at 23 C using a 45 min accelerated low Earth orbit (LEO) cycle regime at 80 percent depth of discharge. One of three cells containing 26 percent KOH has achieved over 28,000 cycles, and the other two 19,000 cycles, without a sign of failure. Two other cells containing 31 percent KOH electrolyte, which is the concentration presently used in aerospace cells, failed after 2,979 and 3,620 cycles. This result indicates that the cycle life of the present type of Ni/H2 cells may be extended by a factor of 5 to 10 simply by lowering the KOH concentration. Long cycle life of a Ni/H2 battery at high depth-of-discharge operation is desired, particularly for an LEO spacecraft application. Typically, battery life of about 30,000 cycles is required for a five year mission in an LEO. Such a cycle life with presently available cells can be assured only at a very low depth-of-discharge operation. Results of testing already show that the cycle life of an Ni/H2 cell is tremendously improved by simply using an electrolyte of low KOH concentration.

Collection of summaries of Sunshine Program achievement reports for fiscal 1981. Hydrogen energy; 1981 nendo sunshine keikaku seika hokokusho gaiyoshu. Suuiso energy

Energy Technology Data Exchange (ETDEWEB)

NONE

1982-04-01

The collection includes research on hydrogen production through the electrolysis of water using an acid-type solid polymer electrolyte, electrolysis of water using an alkali-type solid polymer electrolyte, thermochemical method using an iodine-based cycle, thermochemical method using a bromine-based cycle, thermochemical method using a mixed cycle, high-temperature direct thermolysis, and the utilization of solar radiation. Furthermore, it includes a study of materials to build a iodine-based cycle apparatus. In a research on the transportation and storage of hydrogen, technologies of hydrogen transportation and storage using metallic hydrides are taken up. In a research on the application of hydrogen, technologies of hydrogen combustion and hydrogen-fueled engines are discussed. In a research on hydrogen safety measures, technologies for the prevention of hydrogen explosion disasters and of hydrogen embrittlement of materials in use with hydrogen are studied. In addition, a study is conducted of a hydrogen energy total system, and research and development is carried out of a plant that produces hydrogen by means of the high-temperature high-pressure electrolysis of water. (NEDO)

Thermal integration of SCWR nuclear and thermochemical hydrogen plants

International Nuclear Information System (INIS)

Wang, Z.; Naterer, G.F.; Gabriel, K.S.

2010-01-01

In this paper, the intermediate heat exchange between a Generation IV supercritical water-cooled nuclear reactor (SCWR) and a thermochemical hydrogen production cycle is discussed. It is found that the maximum and range of temperatures of a thermochemical cycle are the dominant parameters that affect the design of its coupling with SCWR. The copper-chlorine (Cu-Cl) thermochemical cycle is a promising cycle that can link with SCWRs. The location of extracting heat from a SCWR to a thermochemical cycle is investigated in this paper. Steam bypass lines downstream of the SCWR core are suggested for supplying heat to the Cu-Cl hydrogen production cycle. The stream extraction location is strongly dependent on the temperature requirements of the chemical steps of the thermochemical cycle. The available quantity of heat exchange at different hours of a day is also studied. It is found that the available heat at most hours of power demand in a day can support an industrial scale steam methane reforming plant if the SCWR power station is operating at full design capacity. (author)

Storage of Renewable Energy by Reduction of CO2 with Hydrogen.

Science.gov (United States)

Züttel, Andreas; Mauron, Philippe; Kato, Shunsuke; Callini, Elsa; Holzer, Marco; Huang, Jianmei

2015-01-01

The main difference between the past energy economy during the industrialization period which was mainly based on mining of fossil fuels, e.g. coal, oil and methane and the future energy economy based on renewable energy is the requirement for storage of the energy fluxes. Renewable energy, except biomass, appears in time- and location-dependent energy fluxes as heat or electricity upon conversion. Storage and transport of energy requires a high energy density and has to be realized in a closed materials cycle. The hydrogen cycle, i.e. production of hydrogen from water by renewable energy, storage and use of hydrogen in fuel cells, combustion engines or turbines, is a closed cycle. However, the hydrogen density in a storage system is limited to 20 mass% and 150 kg/m(3) which limits the energy density to about half of the energy density in fossil fuels. Introducing CO(2) into the cycle and storing hydrogen by the reduction of CO(2) to hydrocarbons allows renewable energy to be converted into synthetic fuels with the same energy density as fossil fuels. The resulting cycle is a closed cycle (CO(2) neutral) if CO(2) is extracted from the atmosphere. Today's technology allows CO(2) to be reduced either by the Sabatier reaction to methane, by the reversed water gas shift reaction to CO and further reduction of CO by the Fischer-Tropsch synthesis (FTS) to hydrocarbons or over methanol to gasoline. The overall process can only be realized on a very large scale, because the large number of by-products of FTS requires the use of a refinery. Therefore, a well-controlled reaction to a specific product is required for the efficient conversion of renewable energy (electricity) into an easy to store liquid hydrocarbon (fuel). In order to realize a closed hydrocarbon cycle the two major challenges are to extract CO(2) from the atmosphere close to the thermodynamic limit and to reduce CO(2) with hydrogen in a controlled reaction to a specific hydrocarbon. Nanomaterials with

Natural gas usage as a heat source for integrated SMR and thermochemical hydrogen production technologies

International Nuclear Information System (INIS)

Jaber, O.; Naterer, G.F.; Dincer, I.

2010-01-01

This paper investigates various usages of natural gas (NG) as an energy source for different hydrogen production technologies. A comparison is made between the different methods of hydrogen production, based on the total amount of natural gas needed to produce a specific quantity of hydrogen, carbon dioxide emissions per mole of hydrogen produced, water requirements per mole of hydrogen produced, and a cost sensitivity analysis that takes into account the fuel cost, carbon dioxide capture cost and a carbon tax. The methods examined are the copper-chlorine (Cu-Cl) thermochemical cycle, steam methane reforming (SMR) and a modified sulfur-iodine (S-I) thermochemical cycle. Also, an integrated Cu-Cl/SMR plant is examined to show the unique advantages of modifying existing SMR plants with new hydrogen production technology. The analysis shows that the thermochemical Cu-Cl cycle out-performs the other conventional methods with respect to fuel requirements, carbon dioxide emissions and total cost of production. (author)

Collection of summaries of Sunshine Program achievement reports for fiscal 1982. Hydrogen energy; 1982 nendo sunshine keikaku seika hokokusho gaiyoshu. Suiso energy

Energy Technology Data Exchange (ETDEWEB)

NONE

1983-04-01

The collection includes achievements of research relating to hydrogen energy. In the research on hydrogen production by electrolysis, electrolysis of water using an acid-type solid polymer electrolyte and electrolysis of water using an alkali-type solid polymer electrolyte are taken up. In the research on hydrogen production by thermochemical methods, studies are conducted on the iodine-based cycle, the bromine-based cycle, materials for devices for the iodine-based cycle, and the mixed cycle. Hydrogen production using high-temperature direct thermolysis and solar radiation is also studied. In the research on hydrogen transportation and storage, use of metallic hydrides in these processes are taken up. In the research on the application of hydrogen, techniques of hydrogen combustion and hydrogen-fueled engines are discussed. In the research on hydrogen safety measures, technologies for the prevention of hydrogen explosions and of hydrogen embrittlement of materials in use with hydrogen are studied. In addition, a study is conducted of a hydrogen energy total system, and research and development is carried out for a plant that produces hydrogen by high-temperature high-pressure electrolysis of water. (NEDO)

Low cycle fatigue behaviors of low alloy steels in 310 .deg. C deoxygenated water

International Nuclear Information System (INIS)

Jang, Hun

2008-02-01

After low cycle fatigue tests of SA508 Gr.1a low alloy steel in 310 .deg. C deoxygenated water, the fatigue surface and the sectioned area of specimens were observed to understand the effect of the cyclic strain rate on the environmentally assisted cracking behaviors. From the fatigue crack morphologies of the specimen tested at a strain rate of 0.008 %/s, unclear ductile striations and blunt crack tip were observed. So, metal dissolution could be the main cracking mechanism of the material at the strain rate. On the other hand, on the fatigue surface of the specimen tested at strain rates of 0.04 and 0.4 %/s, the brittle cracks and the flat facets, which are the evidence of the hydrogen induced cracking, were observed. Also, the tendency of linkage between the main crack and micro-cracks was observed on the sectioned area. Therefore, the main cracking mechanism at the strain rates of 0.04 and 0.4 %/s could be the hydrogen induced cracking. Additionally, the evidence of the dissolved MnS inclusions was observed on the fatigue surface from energy dispersive x-ray spectrometer analyses. So, despite of the low sulfur content of the test material, the sulfides seem to contribute to environmentally assisted cracking of SA508 Gr.1a low alloy steel in 310 .deg. C deoxygenated water. Additionally, our experimental fatigue life data of SA508 Gr.1a low alloy steel (heat A) showed a consistent difference with statistical model produced in argon national laboratory. So, additional low cycle fatigue tests of other heat SA508 Gr.1a (heat B) and SA508 Gr.3 low alloy steels were performed to investigate the effect of material variability on fatigue behaviors of low alloy steels in 310 .deg. C deoxygenated water. In results, the fatigue lives of three low alloy steels were increased following order: SA508 Gr.1a low alloy steel - heat A, SA508 Gr.3 low alloy steel, and SA508 Gr.1a low alloy steel - heat B. From microstructure observation, the fatigue surface of SA508 Gr.1a low alloy

Weak hydrogen bonding interactions influence slip system activity and compaction behavior of pharmaceutical powders.

Science.gov (United States)

Khomane, Kailas S; Bansal, Arvind K

2013-12-01

Markedly different mechanical behavior of powders of polymorphs, cocrystals, hydrate/anhydrate pairs, or structurally similar molecules has been attributed to the presence of active slip planes system in their crystal structures. Presence of slip planes in the crystal lattice allows easier slip under the applied compaction pressure. This allows greater plastic deformation of the powder and results into increased interparticulate bonding area and greater tensile strength of the compacts. Thus, based on this crystallographic feature, tableting performance of the active pharmaceutical ingredients can be predicted. Recently, we encountered a case where larger numbers of CH···O type interactions across the proposed slip planes hinder the slip and thus resist plastic deformation of the powder under the applied compaction pressure. Hence, attention must be given to these types of interactions while identifying slip planes by visualization method. Generally, slip planes are visualized as flat layers often strengthened by a two-dimensional hydrogen-bonding network within the layers or planes. No hydrogen bonding should exist between these layers to consider them as slip planes. Moreover, one should also check the presence of CH···O type interactions across these planes. Mercury software provides an option for visualization of these weak hydrogen bonding interactions. Hence, caution must be exercised while selecting appropriate solid form based on this crystallographic feature. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

Are the lessons of the techno-economic studies on the sulphur-iodine cycle applicable to the other cycles?

International Nuclear Information System (INIS)

Werkoff, F.; Mansilla, C.

2007-01-01

Further advances in nuclear energy system design can broaden the opportunities for the use of nuclear energy. To explore these opportunities, several countries are involved in a forum on the development of next generation nuclear energy systems known as 'Generation IV'. Six concepts have been chosen by the forum, to be studied. The Very High Temperature Reactor (VHTR) offers perspectives for producing electricity and hydrogen with high efficiencies. Nuclear production of hydrogen by thermochemical means is one of the prime candidates for powering the hydrogen economy without producing green house gases. Among them, the Sulphur-Iodine (S-I) thermochemical cycle appeared well fitted with the VHTR, due to the temperature needed for the decomposition of the sulphuric acid. It was invented in the 1970's and it benefits from a revival of interest in the framework of Generation IV. In the last past years, assessments of the S-I process, coupled with a VHTR have been carried out. It appeared that these assessments have to be considered, looking with a particular care to the recommendations of the Generation IV crosscutting economics group [1]: a Generation IV system will: 1. Have a clear life-cost advantage over other energy systems. 2. Have a level of financial risk comparable to other energy projects. The experience gained from techno-economic studies [2, 3] which consider the S-I cycle, indicates that the choice of alternatives cycles to the S-I one must be driven by the characteristic of a previously selected nuclear reactor, mainly the temperature at the nuclear core outlet. Moreover, the net efficiency of the thermochemical cycle must be higher than a reference value defined from the alkaline electrolysis fed by the electricity produced from the selected reactor. Besides, the technical feasibility of the thermochemical processes is not yet established and the production cost of hydrogen from these processes is the result of the sum of several cost factors which are

Diel cycles of hydrogen peroxide in marine bathing waters in Southern California, USA: In situ surf zone measurements

International Nuclear Information System (INIS)

Clark, Catherine D.; De Bruyn, Warren J.; Hirsch, Charlotte M.; Aiona, Paige

2010-01-01

Hydrogen peroxide is photochemically produced in natural waters. It has been implicated in the oxidative-induced mortality of fecal indicator bacteria (FIB), a microbial water quality measure. To assess levels and cycling of peroxide in beach waters monitored for FIB, diel studies were carried out in surf zone waters in July 2009 at Crystal Cove State Beach, Southern California, USA. Maximum concentrations of 160-200 nM were obtained within 1 h of solar noon. Levels dropped at night to 20-40 nM, consistent with photochemical production from sunlight. Day-time production and night-time dark loss rates averaged 16 ± 3 nM h -1 and 12 ± 4 nM h -1 respectively. Apparent quantum yields averaged 0.07 ± 0.02. Production was largely dominated by sunlight, with some dependence on chromophoric dissolved organic matter (CDOM) levels in waters with high absorption coefficients. Peroxide levels measured here are sufficient to cause oxidative-stress-induced mortality of bacteria, affect FIB diel cycling and impact microbial water quality in marine bathing waters.

18th world hydrogen energy conference 2010. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

This CD-ROM contains lectures, power points slides and posters presented on the 18th World Hydrogen Energy Conference. The topics of the conference are: (A). Fuel Cell Basics: 1. Electrochemistry of PEM Fuell Cells; 2. PEM/HT-PEM Fuel Cells: Electrolytes, Stack Components; 3. Direct Fuel Cells; 4. High-Temperature Fuel Cells; 5. Advanced Modelling (B). Existing and Emerging Markets: 1. Off-Grid Power Supply and Premium Power Generation; 2. Space and Aeronautic Applications; 3. APUs for LDV, Trucks, Ships and Airplanes; 4. Portable Applications and Light Traction. (C). Stationary Applications: 1. High-Temperature Fuel Cells; 2. Fuell Cells for Buildings. (D). Transportation Applications: 1. Fuel-Cell Power Trains; 3. Hydrogen Internal Combustion Engines; 4. Systems Analysis and Well-to-Wheel Studies; 5. Demonstration Projects, Costs and Market Introduction; 6 Electrification in Transportation Systems. (E). Fuel Infrastructures: 1. Hydrogen Distribution Technologies; 2. Hydrogen Deployment; 3. Fuel Provision for Early Market Applications. (G). Hydrogen Production Technologies: 1a. Photobiological Hydrogen Production; 1b. Fermentative Hydrogen Production; 1c. The HYVOLUTION Project. (H). Thermochemical Cycles: 3a. Hydrogen from Renewable Electricity; 3b. High-Temperature Electrolysis; 3c Alcaline Electrolysis; 3d PEM Electrolysis; 4a Reforming and Gasification-Fossil Energy Carriers; 4b Reforming and Gasification-Biomass; 5. Hydrogen-Separation Membranes; 6. Hydrogen Systems Assessment;.7. Photocatalysis (I). Storages: 1. Physical Hydrogen Storage; 2a. Metal Hydrides; 2b. Complex Hydrides; 3. Adsorption Technologies; (J). Strategic Analyses: 1. Research + Development Target and Priorities; 2. Life-Cycle Assessment and Economic Impact; 3. Socio-Economic Studies; 4. Education and Public Awareness; 5. Market Introduction; 7. Regional Activities; 8. The Zero Regio Project. (K). Safety Issues: 1. Vehicle and Infrastructural Safety; 2. Regulations, Codes, Standards and Test

18th world hydrogen energy conference 2010. Proceedings

International Nuclear Information System (INIS)

2010-01-01

This CD-ROM contains lectures, power points slides and posters presented on the 18th World Hydrogen Energy Conference. The topics of the conference are: (A). Fuel Cell Basics: 1. Electrochemistry of PEM Fuell Cells; 2. PEM/HT-PEM Fuel Cells: Electrolytes, Stack Components; 3. Direct Fuel Cells; 4. High-Temperature Fuel Cells; 5. Advanced Modelling (B). Existing and Emerging Markets: 1. Off-Grid Power Supply and Premium Power Generation; 2. Space and Aeronautic Applications; 3. APUs for LDV, Trucks, Ships and Airplanes; 4. Portable Applications and Light Traction. (C). Stationary Applications: 1. High-Temperature Fuel Cells; 2. Fuell Cells for Buildings. (D). Transportation Applications: 1. Fuel-Cell Power Trains; 3. Hydrogen Internal Combustion Engines; 4. Systems Analysis and Well-to-Wheel Studies; 5. Demonstration Projects, Costs and Market Introduction; 6 Electrification in Transportation Systems. (E). Fuel Infrastructures: 1. Hydrogen Distribution Technologies; 2. Hydrogen Deployment; 3. Fuel Provision for Early Market Applications. (G). Hydrogen Production Technologies: 1a. Photobiological Hydrogen Production; 1b. Fermentative Hydrogen Production; 1c. The HYVOLUTION Project. (H). Thermochemical Cycles: 3a. Hydrogen from Renewable Electricity; 3b. High-Temperature Electrolysis; 3c Alcaline Electrolysis; 3d PEM Electrolysis; 4a Reforming and Gasification-Fossil Energy Carriers; 4b Reforming and Gasification-Biomass; 5. Hydrogen-Separation Membranes; 6. Hydrogen Systems Assessment;.7. Photocatalysis (I). Storages: 1. Physical Hydrogen Storage; 2a. Metal Hydrides; 2b. Complex Hydrides; 3. Adsorption Technologies; (J). Strategic Analyses: 1. Research + Development Target and Priorities; 2. Life-Cycle Assessment and Economic Impact; 3. Socio-Economic Studies; 4. Education and Public Awareness; 5. Market Introduction; 7. Regional Activities; 8. The Zero Regio Project. (K). Safety Issues: 1. Vehicle and Infrastructural Safety; 2. Regulations, Codes, Standards and Test

Cost Evaluation with G4-ECONS Program for SI based Nuclear Hydrogen Production Plant

International Nuclear Information System (INIS)

Kim, Jong-ho; Lee, Ki-young; Kim, Yong-wan

2014-01-01

Contemporary hydrogen is production is primarily based on fossil fuels, which is not considered as environments friendly and economically efficient. To achieve the hydrogen economy, it is very important to produce a massive amount of hydrogen in a clean, safe and efficient way. Nuclear production of hydrogen would allow massive production of hydrogen at economic prices while avoiding environments pollution reducing the release of carbon dioxide. Nuclear production of hydrogen could thus become the enabling technology for the hydrogen economy. The economic assessment was performed for nuclear hydrogen production plant consisting of VHTR coupled with SI cycle. For the study, G4-ECONS developed by EMWG of GIF was appropriately modified to calculate the LUHC, assuming 36 months of plant construction time, 5 % of annual interest rate and 12.6 % of fixed charge rate. In G4-ECONS program, LUHC is calculated by the following formula; LUHC = (Annualized TCIC + Annualized O-M Cost + Annualized Fuel Cycle Cost + Annualized D-D Cost) / Annual Hydrogen Production Rate

Technical Analysis of Hydrogen Production

Energy Technology Data Exchange (ETDEWEB)

Ali T-Raissi

2005-01-14

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

The hydrogen economy - an opportunity for gas

International Nuclear Information System (INIS)

Soederbaum, J.; Martin, G.; O'Neill, C.

2003-01-01

Natural gas could play a pivotal role in any transition to a hydrogen economy-that is one of the findings of the recently-released National Hydrogen Study, commissioned by the Commonwealth Department of Industry, Tourism and Resources, and undertaken by the consulting firms ACIL Tasman and Parsons Brinckerhoff. The key benefits of hydrogen include zero emissions at the point of combustion (water is the main by-product) and its abundance Hydrogen can be produced from a range of primary energy sources including gas and coal, or through the electrolysis of water. Depending on the process used to manufacture hydrogen (especially the extent to which any associated carbon can be captured and sequestered), life-cycle emissions associated with its production and use can be reduced or entirely eliminated

Comparison of cell encapsulation technologies for single pressure vessel nickel-hydrogen battery

Energy Technology Data Exchange (ETDEWEB)

Rao, G. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center; Vaidyanathan, H. [COMSAT Labs., Clarksburg, MD (United States)

1996-12-31

Two single pressure vessel (SPV) batteries containing 22 series-connected nickel-hydrogen (Ni-H{sub 2}) cells of 19-Ah capacity were designed and procured from Eagle-Picher Industries. The two batteries were similar in mechanical design, dimensions, and composition of the active core. However, they differed in cell encapsulation, location and structure of the gas diffusion membrane, and cell activation. Both batteries have been subjected to detailed flight qualification testing at COMSAT Laboratories. The batteries met the requirements in capacity, capacity retention, discharge voltage, impedance, thermal behavior in vacuum, and response to vibration. The batteries are currently being cycle tested in a low earth orbit (LEO) regime using V-T charge control at a depth of discharge of 40% and at 20 C. The battery design, and its characterization, environmental, and LEO cycle test data are presented.

Thermal tests of a multi-tubular reactor for hydrogen production by using mixed ferrites thermochemical cycle

Science.gov (United States)

Gonzalez-Pardo, Aurelio; Denk, Thorsten; Vidal, Alfonso

2017-06-01

The SolH2 project is an INNPACTO initiative of the Spanish Ministry of Economy and Competitiveness, with the main goal to demonstrate the technological feasibility of solar thermochemical water splitting cycles as one of the most promising options to produce H2 from renewable sources in an emission-free way. A multi-tubular solar reactor was designed and build to evaluate a ferrite thermochemical cycle. At the end of this project, the ownership of this plant was transferred to CIEMAT. This paper reviews some additional tests with this pilot plant performed in the Plataforma Solar de Almería with the main goal to assess the thermal behavior of the reactor, evaluating the evolution of the temperatures inside the cavity and the relation between supplied power and reached temperatures. Previous experience with alumina tubes showed that they are very sensitive to temperature and flux gradients, what leads to elaborate an aiming strategy for the heliostat field to achieve a uniform distribution of the radiation inside the cavity. Additionally, the passing of clouds is a phenomenon that importantly affects all the CSP facilities by reducing their efficiency. The behavior of the reactor under these conditions has been studied.

Hydrogen production at hydro-power plants

Science.gov (United States)

Tarnay, D. S.

A tentative design for hydrogen-producing installations at hydropower facilities is discussed from technological, economic and applications viewpoints. The plants would use alternating current to electrolyze purified river water. The hydrogen would be stored in gas or liquid form and oxygen would be sold or vented to the atmosphere. The hydrogen could later be burned in a turbine generator for meeting peak loads, either in closed or open cycle systems. The concept would allow large hydroelectric plants to function in both base- and peak-load modes, thus increasing the hydraulic utilization of the plant and the capacity factor to a projected 0.90. Electrolyzer efficiencies ranging from 0.85-0.90 have been demonstrated. Excess hydrogen can be sold for other purposes or, eventually, as domestic and industrial fuel, at prices competitive with current industrial hydrogen.

Early construction and operation of the highly contaminated water treatment system in Fukushima Daiichi Nuclear Power Station (4). Assessment of hydrogen behavior in stored Cs adsorption vessel

International Nuclear Information System (INIS)

Kondo, Masahiro; Arai, Takahiro; Nishi, Yoshihisa

2014-01-01

Hydrogen diffusion behavior in a cesium adsorption vessel is assessed. The vessel is used to remove radioactive substance from contaminated water, which is proceeded from Fukushima accident. Experiment and numerical calculation are conducted to clarify the characteristics of natural circulation in the vessel. The natural circulation arising from the temperature difference between inside and outside the vessel is confirmed. We develop an evaluation model to predict the natural circulation and its prediction agrees well with the results obtained by the experiment and the calculation. Using the model, we predict steady and transient behavior of hydrogen concentration. Results indicate that hydrogen concentration is kept lower than the flammability limit when the short vent pipe is open. (author)

Evaluation of hydrogen trapping mechanisms during performance of different hydrogen fugacity in a lean duplex stainless steel

Energy Technology Data Exchange (ETDEWEB)

Silverstein, R., E-mail: barrav@post.bgu.ac.il [Department of Material Science and Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Eliezer, D. [Department of Material Science and Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Glam, B.; Eliezer, S.; Moreno, D. [Soreq Nuclear Research Center, Yavne, 81800 (Israel)

2015-11-05

Hydrogen trapping behavior in a lean duplex stainless steel (LDS) is studied by means of thermal desorption spectrometry (TDS). The susceptibility of a metal to hydrogen embrittlement is directly related to the trap characteristics: source or sink (reversible or irreversible, respectively). Since trapping affects the metal's diffusivity, it has a major influence on the hydrogen assisted cracking (HAC) phenomenon. It is known from previously published works that the susceptibility will depend on the competition between reversible and irreversible traps; meaning a direct relation to the hydrogen's initial state in the steel. In this research the trapping mechanism of LDS, exposed to different hydrogen charging environments, is analyzed by means of TDS. The TDS analysis was supported and confirmed by means of X-ray diffraction (XRD), hydrogen quantitative measurements and microstructural observations. It was found that gaseous charging (which produces lower hydrogen fugacity) creates ∼22% higher activation energy for hydrogen trapping compared with cathodic charging (which produces higher hydrogen fugacity). These results are due to the different effects on the hydrogen behavior in LDS which causes a major difference in the hydrogen contents and different hydrogen assisted phase transitions. The highest activation energy value in the cathodic charged sample was ascribed to the dominant phase transformation of γ → γ{sup ∗}, whereas in the gaseous charged sample it was ascribed to the dominant formation of intermetallic compound, sigma (σ). The relation between hydrogen distribution in LDS and hydrogen trapping mechanism is discussed in details. - Highlights: • The relation between hydrogen distribution and trapping in LDS is discussed. • Hydrogen's initial state in LDS causes different microstructural changes. • Gaseous charged LDS creates higher trapping energy compared to cathodic charged LDS. • The dominant phase transformation in

Stress development in thin yttrium films on hard substrates during hydrogen loading

International Nuclear Information System (INIS)

Dornheim, M.; Pundt, A.; Kirchheim, R.; Molen, S. J. v. d.; Kooij, E. S.; Kerssemakers, J.; Griessen, R.; Harms, H.; Geyer, U.

2003-01-01

Polycrystalline (0002)-textured yttrium (Y) films of 50-500 nm thickness on sapphire substrates were loaded electrolytically with hydrogen (H). The stresses which build up in these films were measured in situ using curvature measurements. The results are compared to the behavior of bulk Y-H. A linear elastic model is used to predict the behavior of clamped thin films. Basic properties of the bulk Y-H phase diagram and elastic constants resemble the measured values of the thin films. Compressive stress builds up during H-loading in the α-Y phase and in the (α-Y+β-YH 2 ) two-phase field, showing an initial stress increase of -1.3 GPa per hydrogen concentration X H (compressive stress). While bulk Y-H samples are known to show a contraction in the β-YH 2 phase during H loading, thin films show no evidence for such a contraction during the first loading cycle of the film. The stress remains constant in the bulk β-phase concentration range (ΔX H =0.1 H/Y). This is attributed to the narrow β-phase field (ΔX H =0.02 H/Y) of the thin film during the first loading. Only samples which have been kept at a hydrogen concentration of about 1.5 H/Y for weeks show tensile stress in the concentration range of the bulk β phase. Amazingly a stress increase of about +0.5 GPa/X H (tensile stress) is measured in the β+γ two-phase field. This is attributed to the smaller in-plane nearest-neighbor distance in the γ phase compared to the β phase. In the γ-phase field compressive stress is built up again, compensating the tensile stress. It increases by -1.3 GPa/X H . In total, the net stress in Y-H films remains comparably small. This could be a reason for the good mechanical stability of such Y-H switchable mirrors during H cycling

Global warming potential of the sulfur-iodine process using life cycle assessment methodology

International Nuclear Information System (INIS)

Lattin, William C.; Utgikar, Vivek P.

2009-01-01

A life cycle assessment (LCA) of one proposed method of hydrogen production - thermochemical water-splitting using the sulfur-iodine cycle couple with a very high-temperature nuclear reactor - is presented in this paper. Thermochemical water-splitting theoretically offers a higher overall efficiency than high-temperature electrolysis of water because heat from the nuclear reactor is provided directly to the hydrogen generation process, instead of using the intermediate step of generating electricity. The primary heat source for the S-I cycle is an advanced nuclear reactor operating at temperatures corresponding to those required by the sulfur-iodine process. This LCA examines the environmental impact of the combined advanced nuclear and hydrogen generation plants and focuses on quantifying the emissions of carbon dioxide per kilogram of hydrogen produced. The results are presented in terms of global warming potential (GWP). The GWP of the system is 2500 g carbon dioxide-equivalent (CO 2 -eq) per kilogram of hydrogen produced. The GWP of this process is approximately one-sixth of that for hydrogen production by steam reforming of natural gas, and is comparable to producing hydrogen from wind- or hydro-electric conventional electrolysis. (author)

Dynamic behavior of Rankine cycle system for waste heat recovery of heavy duty diesel engines under driving cycle

International Nuclear Information System (INIS)

Xie, Hui; Yang, Can

2013-01-01

Highlights: • Waste heat recovery behavior of the RCS during driving cycle was investigated. • Four operating modes were defined to describe the operating process of the RCS under driving cycle. • The operating mode switching is the crucial reason for on-road inefficiency. • The dry and isentropic fluids are superior to the wet ones on the adaptability to unsteady ExGE. • The effects of the vapor parameters on RCT-E and power mode percentage are opposite. - Abstract: The RCS (Rankine cycle system) used to recover the WHE (waste heat energy) from engines has been regarded as one of the most potential ways of achieving higher efficiency. However, it is of great challenge to keep the RCS still in good performance under driving cycle. This paper tries to reveal and explain its on-road inefficiency. The operating process of the RCS under driving cycle was analyzed in advance. Afterwards, four basic operating modes were defined, including startup mode, turbine turning mode, power mode and protection mode. Then, a RCS model was established and operating performances of the RCS under an actual driving cycle were discussed based on this model. The results indicate that the on-road RCS-E (Rankine cycle system efficiency) is as low as 3.63%, which is less than half of the design RCS-E (7.77%) at the rated operating point. Despite the inevitable vapor state fluctuation, it is the operating mode switching during the driving cycle that leads to the on-road inefficiency. Further investigations indicate that the expander safety temperature and its safety margin affected by the working fluids, designed superheat degree and evaporating pressure are the main factors determining the operating mode switching. Finally, the effects of the working fluids, designed superheat degree and evaporating pressure on the operating mode switching and RC (Rankine cycle) efficiencies were profoundly investigated. The study shows that the dry and isentropic fluids are superior to the wet

Hydrogen Process Coupling to Modular Helium Reactors

International Nuclear Information System (INIS)

Shenoy, Arkal; Richards, Matt; Buckingham, Robert

2009-01-01

The U.S. Department of Energy (DOE) has selected the helium-cooled High Temperature Gas-Cooled Reactor (HTGR) as the concept to be used for the Next Generation Nuclear Plant (NGNP), because it is the most advanced Generation IV concept with the capability to provide process heat at sufficiently high temperatures for production of hydrogen with high thermal efficiency. Concurrently with the NGNP program, the Nuclear Hydrogen Initiative (NHI) was established to develop hydrogen production technologies that are compatible with advanced nuclear systems and do not produce greenhouse gases. The current DOE schedule for the NGNP Project calls for startup of the NGNP plant by 2021. The General Atomics (GA) NGNP pre-conceptual design is based on the GA Gas Turbine Modular Helium Reactor (GT-MHR), which utilizes a direct Brayton cycle Power Conversion System (PCS) to produce electricity with a thermal efficiency of 48%. The nuclear heat source for the NGNP consists of a single 600-MW(t) MHR module with two primary coolant loops for transport of the high-temperature helium exiting the reactor core to a direct cycle PCS for electricity generation and to an Intermediate Heat Exchanger (IHX) for hydrogen production. The GA NGNP concept is designed to demonstrate hydrogen production using both the thermochemical sulfur-iodine (SI) process and high-temperature electrolysis (HTE). The two primary coolant loops can be operated independently or in parallel. The reactor design is essentially the same as that for the GT-MHR, but includes the additional primary coolant loop to transport heat to the IHX and other modifications to allow operation with a reactor outlet helium temperature of 950 .deg. C (vs. 850 .deg. C for the GT-MHR). The IHX transfers a nominal 65 MW(t) to the secondary heat transport loop that provides the high-temperature heat required by the SI-based and HTE-based hydrogen production facilities. Two commercial nuclear hydrogen plant variations were evaluated with

USE OF THE MODULAR HELIUM REACTOR FOR HYDROGEN PRODUCTION

International Nuclear Information System (INIS)

SCHULTZ, K.R.

2003-01-01

OAK-B135 A significant ''Hydrogen Economy'' is predicted that will reduce our dependence on petroleum imports and reduce pollution and greenhouse gas emissions. Hydrogen is an environmentally attractive fuel that has the potential to displace fossil fuels, but contemporary hydrogen production is primarily based on fossil fuels. The author has recently completed a three-year project for the US Department of Energy (DOE) whose objective was to ''define an economically feasible concept for production of hydrogen, using an advanced high-temperature nuclear reactor as the energy source''. Thermochemical water-slitting, a chemical process that accomplishes the decomposition of water into hydrogen and oxygen, met this objective. The goal of the first phase of this study was to evaluate thermochemical processes which offer the potential for efficient, cost-effective, large-scale production of hydrogen, and to select one for further detailed consideration. They selected the Sulfur-Iodine cycle. In the second phase, they reviewed all the basic reactor types for suitability to provide the high temperature heat needed by the selected thermochemical water splitting cycle and chose the helium gas-cooled reactor. In the third phase they designed the chemical flowsheet for the thermochemical process and estimated the efficiency and cost of the process and the projected cost of producing hydrogen. These results are summarized in this report

Hydrogen: an energy carrier of the future

Energy Technology Data Exchange (ETDEWEB)

Hamerak, K

1977-02-01

Some advantages and fields of application of hydrogen are outlined in the introduction. Hydrogen production by conventional water electrolysis, by the thermochemical iron-chlorine cycle process, and by a new water electrolysis method still in the laboratory stage are dealt with in which the electrolysis voltage is considerably reduced by the action of solar UV light on an anode consisting of p-conducting material.

Effects of High Mean Stress on High-cycle Fatigue Behavior of PWA 1480

Science.gov (United States)

Majumdar, S.; Antolovich, S. D.; Milligan, W. W.

1985-01-01

PWA 1480 is a potential candidate material for use in the high-pressure fuel turbine blade of the space shuttle main engine. As an engine material it will be subjected to high-cycle fatigue loading superimposed on a high mean stress due to combined centrifugal and thermal loadings. The present paper describes the results obtained in an ongoing program at the Argonne National Laboratory, sponsored by NASA Lewis, to determine the effects of a high mean stress on the high-cycle fatigue behavior of this material. Straight-gauge high-cycle fatigue specimens, 0.2 inch in diameter and with the specimen axis in the 001 direction, were supplied by NASA Lewis. The nominal room temperature yield and ultimate strength of the material were 146 and 154 ksi, respectively. Each specimen was polished with 1-micron diamond paste prior to testing. However, the surface of each specimen contained many pores, some of which were as large as 50 micron. In the initial tests, specimens were subjected to axial-strain-controlled cycles. However, very little cyclic plasticity was observed.

Hydrogen and oxygen behaviors on Porous-Si surfaces observed using a scanning ESD ion microscope

International Nuclear Information System (INIS)

Itoh, Yuki; Ueda, Kazuyuki

2004-01-01

A scanning electron-stimulated desorption (ESD) ion microscope (SESDIM) measured the 2-D images of hydrogen and oxygen distribution on solid surfaces. A primary electron beam at 600 eV, with a pulse width of 220 ns, resulted in ion yields of H + and O + . This SESDIM is applied to the surface analysis of Porous-Si (Po-Si) partially covered with SiN films. During the heating of a specimen of the Po-Si at 800 deg. C under ultra-high-vacuum (UHV) conditions, the components of the surface materials were moved or diffused by thermal decomposition accompanied by a redistribution of hydrogen and oxygen. After cyclic heating of above 800 deg. C, the dynamic behaviors of H + and O + accompanied by the movements of the SiN layers were observed as images of H + and O + . This was because the H + and O + ions have been identified as composite materials by their kinetic energies

Hydrogen Economy Model for Nearly Net-Zero Cities with Exergy Rationale and Energy-Water Nexus

Directory of Open Access Journals (Sweden)

Birol Kılkış

2018-05-01

Full Text Available The energy base of urban settlements requires greater integration of renewable energy sources. This study presents a “hydrogen city” model with two cycles at the district and building levels. The main cycle comprises of hydrogen gas production, hydrogen storage, and a hydrogen distribution network. The electrolysis of water is based on surplus power from wind turbines and third-generation solar photovoltaic thermal panels. Hydrogen is then used in central fuel cells to meet the power demand of urban infrastructure. Hydrogen-enriched biogas that is generated from city wastes supplements this approach. The second cycle is the hydrogen flow in each low-exergy building that is connected to the hydrogen distribution network to supply domestic fuel cells. Make-up water for fuel cells includes treated wastewater to complete an energy-water nexus. The analyses are supported by exergy-based evaluation metrics. The Rational Exergy Management Efficiency of the hydrogen city model can reach 0.80, which is above the value of conventional district energy systems, and represents related advantages for CO2 emission reductions. The option of incorporating low-enthalpy geothermal energy resources at about 80 °C to support the model is evaluated. The hydrogen city model is applied to a new settlement area with an expected 200,000 inhabitants to find that the proposed model can enable a nearly net-zero exergy district status. The results have implications for settlements using hydrogen energy towards meeting net-zero targets.

Hydrogen transport behavior of metal coatings for plasma-facing components

Energy Technology Data Exchange (ETDEWEB)

Anderl, R.A.; Holland, D.F.; Longhurst, G.R. (Idaho National Engineering Lab., Idaho Falls (USA))

1990-12-01

Plasma-facing components for experimental and commercial fusion reactor studies may include cladding or coatings of refractory metals like tungsten on metallic structural substrates such as copper, vanadium alloys and austenitic stainless steel. Issues of safety and fuel economy include the potential for inventory buildup and permeation of tritium implanted into the plasma-facing surface. This paper reports on laboratory-scale studies with 3 keV D{sub 3}{sup +} ion beams to investigate the hydrogen transport behavior in tungsten coatings on substrates of copper. These experiments entailed measurements of the deuterium re-emission and permeation rates of tungsten, copper, and tungsten-coated copper specimens at temperatures ranging from 638 to 825 K and implanting particle fluxes of approximately 5x10{sup 19} D/m{sup 2} s. Diffusion constants and surface recombination coefficients with enhancement factors due to sputtering were obtained from these measurements. These data may be used in calculations to estimate permeation rates and inventory buildups for proposed diverter designs. (orig.).

Hydrogen transport behavior of metal coatings for plasma-facing components

Science.gov (United States)

Anderl, R. A.; Holland, D. F.; Longhurst, G. R.

1990-12-01

Plasma-facing components for experimental and commercial fusion reactor studies may include cladding or coatings of refractory metals like tungsten on metallic structural substrates such as copper, vanadium alloys and austenitic stainless steel. Issues of safety and fuel economy include the potential for inventory buildup and permeation of tritium implanted into the plasma-facing surface. This paper reports on laboratory-scale studies with 3 keV D +3 ion beams to investigate the hydrogen transport behavior in tungsten coatings on substrates of copper. These experiments entailed measurements of the deuterium re-emission and permeation rates for tungsten, copper, and tungsten-coated copper specimens at temperatures ranging from 638 to 825 K and implanting particle fluxes of approximately 5 × 10 19 D/m 2 s. Diffusion constants and surface recombination coefficients with enhancement factors due to sputtering were obtained from these measurements. These data may be used in calculations to estimate permeation rates and inventory buildups for proposed diverter designs.

Hydrogen transport behavior of metal coatings for plasma facing components

International Nuclear Information System (INIS)

Anderl, R.A.; Holland, D.F.; Longhurst, G.R.

1990-01-01

Plasma-facing components for experimental and commercial fusion reactor studies may include cladding or coatings of refractory metals like tungsten on metallic structural substrates such as copper, vanadium alloys and austenitic stainless steel. Issues of safety and fuel economy include the potential for inventory buildup and permeation of tritium implanted into the plasma-facing surface. This paper reports on laboratory-scale studies with 3-keV D 3 + ion beams to investigate the hydrogen transport behavior in tungsten coatings on substrates of copper. These experiments entailed measurements of the deuterium re-emission and permeation rates for tungsten, copper, and tungsten-coated copper specimens at temperatures ranging from 638 K to 825 K and implanting particle fluxes of approximately 5 x 10 19 D/m 2 s. Diffusion constants and surface recombination coefficients with enhancement factors due to sputtering were obtained from these measurements. These data may be used in calculations to estimate permeation rates and inventory buildups for proposed diverter designs. 18 refs., 3 figs., 3 tabs

Electrochemical behavior of heavily cycled nickel electrodes in Ni/H2 cells containing electrolytes of various KOH concentrations

Science.gov (United States)

Lim, H. S.; Verzwyvelt, S. A.

1989-01-01

A study has been made of charge and discharge voltage changes with cycling of Ni/H2 cells containing electrolytes of various KOH concentrations. A study has also been made of electrochemical behavior of the nickel electrodes from the cycled Ni/H2 cells as a function of overcharge amounts. Discharge voltages depressed gradually with cycling for cells having high KOH concentrations (31 to 36 percent), but the voltages increased for those having low KOH concentrations (21 to 26 percent). To determine if there was a crystallographic change of the active material due to cycling, electrochemical behavior of nickel electrodes was studied in an electrolyte flooded cell containing either 31 or 26 percent KOH electrolyte as a function of the amount of overcharge. The changes in discharge voltage appear to indicate crystal structure changes of active material from gamma-phase to beta-phase in low KOH concentrations, and vice versa in high KOH concentration.

Effect of tungsten and tantalum on the low cycle fatigue behavior of reduced activation ferritic/martensitic steels

Energy Technology Data Exchange (ETDEWEB)

Shankar, Vani, E-mail: vani@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Mariappan, K.; Nagesha, A.; Prasad Reddy, G.V.; Sandhya, R.; Mathew, M.D.; Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India)

2012-05-15

Highlights: Black-Right-Pointing-Pointer Effect of tungsten and tantalum on low cycle fatigue behavior of RAFM steels. Black-Right-Pointing-Pointer Both alloying elements W and Ta improved fatigue life. Black-Right-Pointing-Pointer Increase in Ta content improved fatigue life more than W. Black-Right-Pointing-Pointer Optimization of W content at 1.4 wt.%. Black-Right-Pointing-Pointer Softening behavior closely related to W and Ta content. - Abstract: Reduced activation ferritic/martensitic (RAFM) steels are candidate materials for the test blanket modules of International Thermonuclear Experimental Reactor (ITER). Several degradation mechanisms such as thermal fatigue, low cycle fatigue, creep fatigue interaction, creep, irradiation hardening, swelling and phase instability associated irradiation embrittlement must be understood in order to estimate the component lifetime and issues concerning the structural integrity of components. The current work focuses on the effect of tungsten and tantalum on the low cycle fatigue (LCF) behavior of RAFM steels. Both alloying elements tungsten and tantalum improved the fatigue life. Influence of Ta on increasing fatigue life was an order of magnitude higher than the influence of W on improving the fatigue life. Based on the present study, the W content was optimized at 1.4 wt.%. Softening behavior of RAFM steels showed a strong dependence on W and Ta content in RAFM steels.

Operating Point Optimization of a Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Steam Turbine (SOFC-ST Plant

Directory of Open Access Journals (Sweden)

Juanjo Ugartemendia

2013-09-01

Full Text Available This paper presents a hydrogen powered hybrid solid oxide fuel cell-steam turbine (SOFC-ST system and studies its optimal operating conditions. This type of installation can be very appropriate to complement the intermittent generation of renewable energies, such as wind generation. A dynamic model of an alternative hybrid SOFC-ST configuration that is especially suited to work with hydrogen is developed. The proposed system recuperates the waste heat of the high temperature fuel cell, to feed a bottoming cycle (BC based on a steam turbine (ST. In order to optimize the behavior and performance of the system, a two-level control structure is proposed. Two controllers have been implemented for the stack temperature and fuel utilization factor. An upper supervisor generates optimal set-points in order to reach a maximal hydrogen efficiency. The simulation results obtained show that the proposed system allows one to reach high efficiencies at rated power levels.

Hydrogen storing and electrical properties of hyperbranched polymers-based nanoporous materials

International Nuclear Information System (INIS)

Abdel Rehim, Mona H.; Ismail, Nahla; Badawy, Abd El-Rahman A.A.; Turky, Gamal

2011-01-01

Highlights: · The hydrogen storage capacity of hyperbranched P-Urea, PAMAM and PAMAM and VO x is studied and electrical properties of the samples are also investigated; the measurements showed complete insulating behavior at hydrogenation measuring temperature. These investigations ensure that the polymer conductivity does not play a role in hydrogen uptake, also hyperbranched polymers are promising materials for hydrogen storage. · Electrical properties measurements for the samples showed complete insulating behavior at hydrogenation measuring temperature. · These investigations ensure that the polymer conductivity does not play a role in hydrogen uptake, also hyperbranched polymers are promising materials for hydrogen storage. - Abstract: Hydrogen storage and electrical properties of different hyperbranched polymer systems beside a nanocomposite are studied. The polymers examined are aliphatic hyperbranched poly urea (P-Urea), polyamide amine (PAMAM) and polyamide amine/vanadium oxide (PAMAM/VO x ) nanocomposite. At 80 K and up to 20 bar hydrogen pressure, the hydrogen storage capacity of hyperbranched P-Urea reached 1.6 wt%, 0.9 wt% in case of PAMAM and 0.6 wt% for VO x . The hydrogen storage capacity significantly enhanced when PAMAM and VO x form a nanocomposite and increased up to 2 wt%. At 298 K and up to 20 bar, all the samples did not show measurable hydrogen uptake. Electrical properties of the samples are also investigated; the measurements showed complete insulating behavior at hydrogenation measuring temperature. These investigations ensure that the polymer conductivity does not play a role in hydrogen uptake, also hyperbranched polymers are promising materials for hydrogen storage.

High temperature corrosion in the thermochemical hydrogen production from nuclear heat

International Nuclear Information System (INIS)

Coen-Porisini, F.; Imarisio, G.

1976-01-01

In the production of hydrogen by water decomposition utilizing nuclear heat, a multistep process has to be employed. Water and the intermediate chemical products reach in chemical cycles giving hydrogen and oxygen with regeneration of the primary products used. Three cycles are examined, characterized by the presence of halide compounds and particularly hydracids at temperatures up to 800 0 C. Corrosion tests were carried out in hydrobromic acid, hydrochloric acid, ferric chloride solutions, and hydriodic acid

Measuring the distribution of equity in terms of energy, environmental, and economic costs in the fuel cycles of alternative fuel vehicles with hydrogen pathway scenarios

Science.gov (United States)

Meyer, Patrick E.

Numerous analyses exist which examine the energy, environmental, and economic tradeoffs between conventional gasoline vehicles and hydrogen fuel cell vehicles powered by hydrogen produced from a variety of sources. These analyses are commonly referred to as "E3" analyses because of their inclusion of Energy, Environmental, and Economic indicators. Recent research as sought a means to incorporate social Equity into E3 analyses, thus producing an "E4" analysis. However, E4 analyses in the realm of energy policy are uncommon, and in the realm of alternative transportation fuels, E4 analyses are extremely rare. This dissertation discusses the creation of a novel E4 simulation tool usable to weigh energy, environmental, economic, and equity trade-offs between conventional gasoline vehicles and alternative fuel vehicles, with specific application to hydrogen fuel cell vehicles. The model, dubbed the F uel Life-cycle Analysis of Solar Hydrogen -- Energy, Environment, Economic & Equity model, or FLASH-E4, is a total fuel-cycle model that combines energy, environmental, and economic analysis methodologies with the addition of an equity analysis component. The model is capable of providing results regarding total fuel-cycle energy consumption, emissions production, energy and environmental cost, and level of social equity within a population in which low-income drivers use CGV technology and high-income drivers use a number of advanced hydrogen FCV technologies. Using theories of equity and social indicators conceptually embodied in the Lorenz Curve and Gini Index, the equity of the distribution of societal energy and environmental costs are measured for a population in which some drivers use CGVs and other drivers use FCVs. It is found, based on baseline input data representative of the United States (US), that the distribution of energy and environmental costs in a population in which some drivers use CGVs and other drivers use natural gas-based hydrogen FCVs can be

Dimeric Self-assembling via Hydrogen Bonding and Emissive Behavior of a New Copper (I Complex

Directory of Open Access Journals (Sweden)

Juciely M. dos Reis

2017-04-01

Full Text Available This work describes the synthesis, structural characterization and emissive behavior of a new copper (I complex based on 1-thiocarbamoyl-5-(4-methoxiphenyl-3-phenyl-4,5-dihydro-1H-pyrazole ligand. A dimeric self-assembling via hydrogen bonding was determined by analyzing the short contacts present in the solid-state structure by means of X-ray crystallography. The spectroscopic properties were determined using UV-Vis and fluorescence experiments and an interesting behavior as bluish luminescence was assigned mainly to the mixed (MLCT + IL electronic transitions of the Cu(Id10 ® (S=C–Nligand type. The complete characterization of the new copper (I complex also included elemental analyses and IR spectroscopy. DOI: http://dx.doi.org/10.17807/orbital.v9i1.952

Thermo analytic investigation of hydrogen effusion behavior - sensor evaluation and calibration

Energy Technology Data Exchange (ETDEWEB)

Ried, P.; Gaber, M.; Beyer, K.; Mueller, R.; Kipphardt, H.; Kannengiesser, T. [BAM, Federal Institute for Material Research and Testing, Berlin (Germany)

2011-01-15

The well established carrier gas analysis (CGA) method was used to test different hydrogen detectors comprising a thermal conductivity detector (TCD) and a metal oxide semiconducting (MOx) sensor. The MOx sensor provides high hydrogen sensitivity and selectivity, whereas the TCD exhibits a much shorter response time and a linear hydrogen concentration dependency. Therefore, the TCD was used for quantitative hydrogen concentration measurements above 50 {mu}mol/mol. The respective calibration was made using N{sub 2}/H{sub 2} gas mixtures. Furthermore, the hydrogen content and degassing behaviour of titanium hydride (TiH{sub 2-x}) was studied. This material turned out to be a potential candidate for a solid sample calibration. Vacuum hot extraction (VHE) coupled with a mass spectrometer (MS) was then calibrated with TiH{sub 2-x} as transfer standard. The calibration was applied for the evaluation of the hydrogen content of austenitic steel samples (1.4301) and the comparison of CGA-TCD and VHE-MS. (Copyright copyright 2011 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Hydrogen production by nuclear heat

International Nuclear Information System (INIS)

Crosbie, Leanne M.; Chapin, Douglas

2003-01-01

A major shift in the way the world obtains energy is on the horizon. For a new energy carrier to enter the market, several objectives must be met. New energy carriers must meet increasing production needs, reduce global pollution emissions, be distributed for availability worldwide, be produced and used safely, and be economically sustainable during all phases of the carrier lifecycle. Many believe that hydrogen will overtake electricity as the preferred energy carrier. Hydrogen can be burned cleanly and may be used to produce electricity via fuel cells. Its use could drastically reduce global CO 2 emissions. However, as an energy carrier, hydrogen is produced with input energy from other sources. Conventional hydrogen production methods are costly and most produce carbon dioxide, therefore, negating many of the benefits of using hydrogen. With growing concerns about global pollution, alternatives to fossil-based hydrogen production are being developed around the world. Nuclear energy offers unique benefits for near-term and economically viable production of hydrogen. Three candidate technologies, all nuclear-based, are examined. These include: advanced electrolysis of water, steam reforming of methane, and the sulfur-iodine thermochemical water-splitting cycle. The underlying technology of each process, advantages and disadvantages, current status, and production cost estimates are given. (author)

A study of hydrogen effects on fracture behavior of radioactive waste storage tanks. Final report, October 1992-September 1994

International Nuclear Information System (INIS)

Murty, K.L.; Elleman, T.S.

1994-01-01

The processing of high-level radioactive wastes now stored at Hanford and Savannah River Laboratories will continue over many years and it will be necessary for some of the liquids to remain in the tanks until well into the next century. Continued tank integrity is therefore an issue of prime importance and it will be necessary to understand any processes which could lead to tank failure. Hydrogen embrittlement resulting from absorption of radiolytic hydrogen could alter tank fracture behavior and be an issue in evaluating the effect of stresses on the tanks from rapid chemical oxidation-reduction reactions. The intense radiation fields in some of the tanks could be a factor in increasing the hydrogen permeation rates through protective oxide films on the alloy surface and be an additional factor in contributing to embrittlement. The project was initiated in October 1992 for a two year period to evaluate hydrogen uptake in low carbon steels that are representative of storage tanks. Steel specimens were exposed to high gamma radiation fields to generate radiolytic hydrogen and to potentially alter the protective surface films to increase hydrogen uptake. Direct measurements of hydrogen uptake were made using tritium as a tracer and fracture studies were undertaken to determine any alloy embrittlement. The rates of hydrogen uptake were noted to be extremely low in the experimental steels. Gamma radiation did not reveal any significant changes in the mechanical and fracture characteristics following exposures as long as a month. It is highly desirable to investigate further the tritium diffusion under stress in a cracked body where stress-assisted diffusion is expected to enhance these rates. More importantly, since welds are the weakest locations in the steel structures, the mechanical and fracture tests should be performed on welds exposed to tritium with and without stressed crack-fronts

Needs of thermal-hydraulic codes for analyzing hydrogen behavior of future chinese NPPs

International Nuclear Information System (INIS)

Zhiwei Zhou; Jianjun Xiao; Mengjia Yang

2005-01-01

severe accident management guidelines are therefore needed for dealing with both the in-vessel and ex-vessel phenomena, including hydrogen generation, diffusion/convection and deflagration/detonation. To develop the sophisticated thermalhydraulic codes for analyzing severe accident related hydrogen behavior of a light water reactor system is quite expensive and rather unrealistic for China along to bear the cost. Therefore, the most effective way for China to establish the design capability of analyzing severe accident for new nuclear power plant projects is to participate the international or multi-national R and D program, such as EUROATOM cost-sharing program and GEN-IV program, etc. By international cooperation, China can not only gain in most extent the successful experience of the countries with advanced technology in developing nuclear power plants, but also contribute itself most effectively in keeping the momentum of enlarging the peaceful utilization of nuclear energy in the world. Certainly, the future Chinese nuclear power market will be a significant industrial driver for developing the-state-of-the-art thermal-hydraulic codes, including hydrogen behavior analysis codes. This paper also reports some computational study on hydrogen diffusion/convection behavior in the containment related to Daya Bay NPP severe accident analysis with CFD code GASFLOW. The code validation were largely carried out in past few years in Germany and had been applied to EPR and other German NPPs. (authors)

Semiempirical quantum model approach for hydrogen adsorption in ZrNi alloys

Energy Technology Data Exchange (ETDEWEB)

Chen, Bin-Hao, E-mail: binhao17@gmail.com [Department of Energy Application Engineering, Far East University, No. 49, Zhonghua Rd., Xinshi Dist., Tainan City 74448, Taiwan, ROC (China); Huang, Chien-Chung [Department of Hydrogen Energy and Fuel Cells, Green Energy and Eco-Technology Center, ITRI, No. 49, Zhonghua Rd., Xinshi Dist., Tainan City 74448, Taiwan, ROC (China); Yeh, Yen-Lian; Jang, Ming-Jyi [Department of Automation and Control Engineering, Far East University, No. 49, Zhonghua Rd., Xinshi Dist., Tainan City 74448, Taiwan, ROC (China)

2013-12-15

Highlights: •The hydrogen diffusion behavior in solid ZrNi alloy performs clearly by MD. •Shear and Young’s modulus agree with the experiment study very well. •Current model can apply to hydrogen-tech material development. -- Abstract: Hydrogen storage is an important topic because of its relevance to the future energy economy. Hydrogen diffusivity in materials plays an important role in hydrogen technology both for hydrogen separation and hydrogen storage. To clarify the mechanism of the rate-controlling step, diffusion mechanism of hydrogen in metallic materials is studied by molecular dynamics method. This study performs semi-empirical-quantum molecular dynamic simulations in order to clarify hydrogen atom diffusion behavior in ZrNi alloys materials. We investigate the mechanical properties change associated with temperature variation for ZrNi base alloys and also consider the influence of materials micro-structure change of hydrogen diffusion. Finally, current work presents a theoretically prediction of dynamical diffusion coefficient to compare diffusion kinetics of crystalline and amorphous structure.

Hydrogen-Oxygen PEM Regenerative Fuel Cell at NASA Glenn Research Center

Science.gov (United States)

Bents, David J.

2004-01-01

The NASA Glenn Research Center has constructed a closed-cycle hydrogen-oxygen PEM regenerative fuel cell (RFC) to explore its potential use as an energy storage device for a high altitude solar electric aircraft. Built up over the last 2 years from specialized hardware and off the shelf components the Glenn RFC is a complete "brassboard" energy storage system which includes all the equipment required to (1) absorb electrical power from an outside source and store it as pressurized hydrogen and oxygen and (2) make electrical power from the stored gases, saving the product water for re-use during the next cycle. It consists of a dedicated hydrogen-oxygen fuel cell stack and an electrolyzer stack, the interconnecting plumbing and valves, cooling pumps, water transfer pumps, gas recirculation pumps, phase separators, storage tanks for oxygen (O2) and hydrogen (H2), heat exchangers, isolation valves, pressure regulators, nitrogen purge provisions, instrumentation, and other components. It specific developmental functions include: (1) Test fuel cells and fuel cell components under repeated closed-cycle operation (nothing escapes; everything is used over and over again). (2) Simulate diurnal charge-discharge cycles (3) Observe long-term system performance and identify degradation and loss mechanisms. (4) Develop safe and convenient operation and control strategies leading to the successful development of mission-capable, flight-weight RFC's.

Simulation of hydrogen and hydrogen-assisted propane ignition in Pt catalyzed microchannel

Energy Technology Data Exchange (ETDEWEB)

Seshadri, Vikram; Kaisare, Niket S. [Department of Chemical Engineering, Indian Institute of Technology - Madras, Chennai 600 036 (India)

2010-11-15

This paper deals with self-ignition of catalytic microburners from ambient cold-start conditions. First, reaction kinetics for hydrogen combustion is validated with experimental results from the literature, followed by validation of a simplified pseudo-2D microburner model. The model is then used to study the self-ignition behavior of lean hydrogen/air mixtures in a Platinum-catalyzed microburner. Hydrogen combustion on Pt is a very fast reaction. During cold start ignition, hydrogen conversion reaches 100% within the first few seconds and the reactor dynamics are governed by the ''thermal inertia'' of the microburner wall structure. The self-ignition property of hydrogen can be used to provide the energy required for propane ignition. Two different modes of hydrogen-assisted propane ignition are considered: co-feed mode, where the microburner inlet consists of premixed hydrogen/propane/air mixtures; and sequential feed mode, where the inlet feed is switched from hydrogen/air to propane/air mixtures after the microburner reaches propane ignition temperature. We show that hydrogen-assisted ignition is equivalent to selectively preheating the inlet section of the microburner. The time to reach steady state is lower at higher equivalence ratio, lower wall thermal conductivity, and higher inlet velocity for both the ignition modes. The ignition times and propane emissions are compared. Although the sequential feed mode requires slightly higher amount of hydrogen, the propane emissions are at least an order of magnitude lower than the other ignition modes. (author)

Palladium alloys for hydrogen diffusion

International Nuclear Information System (INIS)

1977-01-01

A palladium-base alloy with tin and/or a silicon addition and its use in the production of hydrogen from water via a cycle of chemical reactions, of which the decomposition of HI into H 2 and I 2 is the most important, is described

Prospect of HTGRs for hydrogen production in Indonesia

International Nuclear Information System (INIS)

Rusli, A.; Dasuki, A.S.; Rahman, M.; Nuriman; Sudarto

1997-01-01

Hydrogen energy system is interesting to many people of the world that because of hydrogen promised to save our planet earth from destroying of burning of fossil fuels. The selected development of hydrogen production from water such as electrolysis and thermochemical cycles are evaluated. These processes are allowed to split the water at lower temperature, still in the range of HTGRs' working temperature. An overview of related studies in recent years enables the development of research to be followed, studied and evaluated are mentioned. The prospect of hydrogen market in Indonesia and economic consideration based on previous studied are also analyzed and evaluated. (author). 11 refs, 5 figs, 13 tabs

Influence of Manufacturing Parameters on Microstructure and Hydrogen Sorption Behavior of Electron Beam Melted Titanium Ti-6Al-4V Alloy.

Science.gov (United States)

Pushilina, Natalia; Syrtanov, Maxim; Kashkarov, Egor; Murashkina, Tatyana; Kudiiarov, Viktor; Laptev, Roman; Lider, Andrey; Koptyug, Andrey

2018-05-10

Influence of manufacturing parameters (beam current from 13 to 17 mA, speed function 98 and 85) on microstructure and hydrogen sorption behavior of electron beam melted (EBM) Ti-6Al-4V parts was investigated. Optical and scanning electron microscopies as well as X-ray diffraction were used to investigate the microstructure and phase composition of EBM Ti-6Al-4V parts. The average α lath width decreases with the increase of the speed function at the fixed beam current (17 mA). Finer microstructure was formed at the beam current 17 mA and speed function 98. The hydrogenation of EBM Ti-6Al-4V parts was performed at the temperatures 500 and 650 °С at the constant pressure of 1 atm up to 0.3 wt %. The correlation between the microstructure and hydrogen sorption kinetics by EBM Ti-6Al-4V parts was demonstrated. Lower average hydrogen sorption rate at 500 °C was in the sample with coarser microstructure manufactured at the beam current 17 mA and speed function 85. The difference of hydrogen sorption kinetics between the manufactured samples at 650 °C was insignificant. The shape of the kinetics curves of hydrogen sorption indicates the phase transition α H + β H →β H .

A Simulation Study of Inter Heat Exchanger Process in SI Cycle Process for Hydrogen Production

International Nuclear Information System (INIS)

Shin, Jae Sun; Cho, Sung Jin; Choi, Suk Hoon; Qasim, Faraz; Lee, Euy Soo; Park, Sang Jin; Lee, Heung N.; Park, Jae Ho; Lee, Won Jae

2014-01-01

SI Cyclic process is one of the thermochemical hydrogen production processes using iodine and sulfur for producing hydrogen molecules from water. VHTR (Very High Temperature Reactor) can be used to supply heat to hydrogen production process, which is a high temperature nuclear reactor. IHX (Intermediate Heat Exchanger) is necessary to transfer heat to hydrogen production process safely without radioactivity. In this study, the strategy for the optimum design of IHX between SI hydrogen process and VHTR is proposed for various operating pressures of the reactor, and the different cooling fluids. Most economical efficiency of IHX is also proposed along with process conditions

A method for generating hydrogen from water

International Nuclear Information System (INIS)

Godin, Paul; Mascarello, Jean; Millet, Jacques.

1974-01-01

Description is given of a method and an installation for generating hydrogen from water, through an endothermic cycle of several successive chemical reactions involving intermediate substances regenerated during said cycle, said reactions occuring at different temperatures. The reaction which takes place at the highest temperature is carried out electrochemically. This can be applied to power-generating units comprising a nuclear reactor [fr

Effect of Thermal Cycling on the Tensile Behavior of Polymer Composites Reinforced by Basalt and Carbon Fibers

Science.gov (United States)

Khalili, S. Mohammad Reza; Najafi, Moslem; Eslami-Farsani, Reza

2017-01-01

The aim of the present work was to investigate the effect of thermal cycling on the tensile behavior of three types of polymer-matrix composites — a phenolic resin reinforced with woven basalt fibers, woven carbon fibers, and hybrid basalt and carbon fibers — in an ambient environment. For this purpose, tensile tests were performed on specimens previously subjected to a certain number of thermal cycles. The ultimate tensile strength of the specimen reinforced with woven basalt fibers had by 5% after thermal cycling, but the strength of the specimen with woven carbon fibers had reduced to a value by 11% higher than that before thermal cycling.