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Sample records for hydride sorption cryocooler

  1. Effects of metastability on hydrogen sorption in fluorine substituted hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Pinatel, E.R.; Corno, M.; Ugliengo, P.; Baricco, M., E-mail: marcello.baricco@unito.it

    2014-12-05

    Highlights: • Fluorine substitution in simple metal hydrides has been modelled. • The stability of the MH{sub (1−x)}F{sub x} solid solutions has been discussed. • Conditions for reversibility of sorption reactions have been suggested. - Abstract: In this work ab initio calculations and Calphad modelling have been coupled to describe the effect of fluorine substitution on the thermodynamics of hydrogenation–dehydrogenation in simple hydrides (NaH, AlH{sub 3} and CaH{sub 2}). These example systems have been used to discuss the conditions required for the formation of a stable hydride–fluoride solid solution necessary to obtain a reversible hydrogenation reaction.

  2. Characterization of sorption compressor for mixed refrigerant J-T cryocooler

    Science.gov (United States)

    Mehta, Rohitkumar; Bapat, Shridhar; Atrey, Milind

    2012-06-01

    The requirement of a cryocooler with minimum vibrations for space borne system and highly sophisticated electronic devices for ground application, has led to the development of sorption compressor type J-T cryocooler. The adsorption capacity of any adsorbent material increases with an increase in pressure and decreases with an increase in temperature. In a Sorption compressor, adsorbed gases are desorbed in a confined volume by raising temperature of the sorption bed which results in increase in pressure of gas. A uniform temperature across the sorption bed ensures maximum discharge from the compressor amounting to higher flow rates and longer cycle time on account of reduced residual loading. In addition, it is also very important to determine the adsorption capacity of any material with respect to the gas or gases to be adsorbed as this varies with source of the adsorbent. The present work reports the characterization of a fully operational two-cell sorption compressor developed. The sorption compressor is characterized for discharge pressure variation with cycle time; this is essentially a function of a) the amount of adsorbent, b) the adsorption capacity for respective gas or gases, c) desorption temperature and its uniformity, and d) system dead volume. The present paper analyses these aspects theoretically and the results are compared with the experimental data obtained for individual gases as well as for gas mixtures. The effect of gas distribution on temperature uniformity across the bed and of heater power on high pressure generated is also studied. The paper also discusses the pressure profile obtained for a given amount of adsorbent for different gas or gas mixture. The work, based on the results obtained so far is being further extended for a four cell sorption compressor.

  3. 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

  4. The Planck Sorption Cooler: Using Metal Hydrides to Produce 20 K

    Science.gov (United States)

    Pearson, David P.; Bowman, R.; Prina, M.; Wilson, P.

    2006-01-01

    The Jet Propulsion Laboratory has built and delivered two continuous closed cycle hydrogen Joule-Thomson (JT) cryocoolers for the ESA Planck mission, which will measure the anisotropy in the cosmic microwave background. The metal hydride compressor consists of six sorbent beds containing LaNi4.78Sn0.22 alloy and a low pressure storage bed of the same material. Each sorbent bed contains a separate gas-gap heat switch that couples or isolates the bed with radiators during the compressor operating cycle. ZrNiHx hydride is used in this heat switch. The Planck compressor produces hydrogen gas at a pressure of 48 Bar by heating the hydride to approx.450 K. This gas passes through a cryogenic cold end consisting of a tube-in-tube heat exchanger, three pre-cooling stages to bring the gas to nominally 52 K, a JT value to expand the gas into the two-phase regime at approx.20 K, and two liquid - vapor heat exchangers that must remove 190 and 646 mW of heat respectively.

  5. Optimized autonomous operations of a 20 K space hydrogen sorption cryocooler

    Energy Technology Data Exchange (ETDEWEB)

    Borders, J.; Prina, M.; Pearson, D.; Bhandari, P. [California Inst. of Technology, Jet Propulsion Lab., Pasadena, CA (United States); Morgante, G. [California Inst. of Technology, Jet Propulsion Lab., Pasadena, CA (United States); IASF/CNR-Sezione di Bologna, Bologna (Italy)

    2004-08-01

    A fully redundant hydrogen sorption cryocooler is being developed for the European Space Agency Planck mission, dedicated to the measurement of the temperature anisotropies of the cosmic microwave background radiation with unprecedented sensitivity and resolution [Advances in Cryogenic Engineering 45A (2000) 499]. In order to achieve this ambitious scientific task, this cooler is required to provide a stable temperature reference ({approx}20 K) and appropriate cooling ({approx}1 W) to the two instruments on-board, with a flight operational lifetime of 18 months. During mission operations, communication with the spacecraft will be possible in a restricted time-window, not longer than 2 h/day. This implies the need for an operations control structure with the required robustness to safely perform autonomous procedures. The cooler performance depends on many operating parameters (such as the temperatures of the pre-cooling stages and the warm radiator), therefore the operation control system needs the capability to adapt to variations of these boundary conditions, while maintaining safe operating procedures. An engineering bread board (EBB) cooler was assembled and tested to evaluate the behavior of the system under conditions simulating flight operations and the test data were used to refine and improve the operation control software. In order to minimize scientific data loss, the cooler is required to detect all possible failure modes and to autonomously react to them by taking the appropriate action in a rapid fashion. Various procedures and schemes both general and specific in nature were developed, tested and implemented to achieve these goals. In general, the robustness to malfunctions was increased by implementing an automatic classification of anomalies in different levels relative to the seriousness of the error. The response is therefore proportional to the failure level. Specifically, the start-up sequence duration was significantly reduced, allowing a much

  6. 8th International Cryocooler Conference

    CERN Document Server

    1995-01-01

    The last few years have witnessed a substantial maturing of long life Stirling-cycle cryocoolers built upon the heritage of the flexure-bearing cryocoolers from Oxford University, and have seen the emergence of mature pulse tube cryocoolers competing head-to-head with the Stirling cryocoolers. Hydrogen sorption cryocoolers, Gifford-McMahon cryocoolers with rare earth regenerators, and helium Joule-Thomson cryocoolers have also made tremendous progress in opening up applications in the 4 K to 10 K temperature range. Tactical Stirling cryocoolers, now commonplace in the defense industry, are finding application in a number of cost­ constrained commercial applications and space missions, and are achieving ever longer lives as they move to linear-drive, clearance-seal compressors. Building on this expanding availability of commercially viable cryocoolers, numerous new applications are being enabled; many of these involve infrared imaging systems, and high­ temperature superconductors in the medical and ...

  7. Reversible Li-insertion in nanoscaffolds: A promising strategy to alter the hydrogen sorption properties of Li-based complex hydrides

    NARCIS (Netherlands)

    Ngene, Peter; Verkuijlen, Margriet H. W.; Barre, Charlotte; Kentgens, Arno P. M.; de Jongh, Petra E.

    Intercalation and de-intercalation of lithium into graphene layers is a well-established phenomenon in Li-ion battery technology. Here we show how this phenomenon can be exploited to destabilize, and alter the hydrogen sorption behaviour of Li-based metal hydrides (LiBH4 and LiAlH4), thereby

  8. Reversible Li-insertion in nanoscaffolds: A promising strategy to alter the hydrogen sorption properties of Li-based complex hydrides

    NARCIS (Netherlands)

    Ngene, Peter; Verkuijlen, Margriet H. W.; Barre, Charlotte; Kentgens, Arno P. M.; de Jongh, Petra E.

    2016-01-01

    Intercalation and de-intercalation of lithium into graphene layers is a well-established phenomenon in Li-ion battery technology. Here we show how this phenomenon can be exploited to destabilize, and alter the hydrogen sorption behaviour of Li-based metal hydrides (LiBH4 and LiAlH4), thereby achievi

  9. Effect of TiO2 nanoparticles on the hydrogen sorption characteristics of magnesium hydride.

    Science.gov (United States)

    Pandey, Sunita K; Bhatnagar, Ashish; Shahi, Rohit R; Hudson, M Sterlin Leo; Singh, Milind K; Srivastava, O N

    2013-08-01

    The present paper explores the enhancement in hydrogen sorption behavior of MgH2 with TiO2 nanoparticles. The catalytic effect of TiO2 nanoparticles with different sizes (7, 25, 50, 100 and 250 nm) were used for improving the sorption characteristics of MgH2. The MgH2 catalyzed with 50 nm of TiO2 exhibited the optimum catalytic effect for hydrogen sorption behavior. The desorption temperature of MgH2 catalyzed through 50 nm TiO2 was found to be 310 degrees C. This is 80 degrees C lower as compared to MgH2 having a desorption temperature of 390 degrees C. It was noticed that the dehydrogenated MgH2 catalyzed with 50 nm TiO2 reabsorbed 5.1 wt% of H2 within 6 minutes at temperature and pressure of 250 degrees C and 50 atm, respectively. The 50 nm TiO2 catalyst lowered the absorption activation energy of MgH2 from - 92 to - 52.7 kJ mol(-1).

  10. In-situ Hydrogen Sorption 2D-ACAR Facility for the Study of Metal Hydrides for Hydrogen Storage

    Science.gov (United States)

    Legerstee, W. J.; de Roode, J.; Anastasopol, A.; Falub, C. V.; Eijt, S. W. H.

    We developed a dedicated hydrogen sorption setup coupled to a positron 2D-ACAR (two-dimensional Angular Correlation of Annihilation Radiation) setup employing a 22Na-source, which will enable to collect 2D-ACAR momentum distributions in-situ as a function of temperature, hydrogen pressure and hydrogen content. In parallel, a dedicated glovebox was constructed for handling air-sensitive metal and metal hydride samples, with a special entrance for the 2D-ACAR sample insert. The 2D-ACAR setup was tested in first measurements on a Pd0.75Ag0.25 foil and on a ball-milled MgH2 powder in both the hydrogen loaded and desorbed states. The hydrogen loaded Pd0.75Ag0.25Hx sample was kept under a 1 bar hydrogen pressure to prevent partial desorption during measurements at room temperature. The collected 2D-ACAR distributions of Pd0.75Ag0.25 and Pd0.75Ag0.25Hx showed similar features as observed in previous studies. The broadening of the ACAR distributions observed for the Mg to MgH2 metal-insulator transition was compared in a quantitative manner to ab-initio calculations reported in the literature.

  11. The effect of metal oxide additives on the hydrogen sorption behaviour of magnesium hydride

    OpenAIRE

    2007-01-01

    MgH2 is considered to be one of the most promising options for a solid state hydrogen storage material. For practical use it is still imperative to find a convenient means of overcoming its slow kinetics and high stability. In this investigation, a range of binary and ternary metal oxides of aluminium, silicon, titanium, and zirconium, as well as Pd-modified Ti02 samples, were prepared and characterised. The prepared oxides were ball milled with MgH2, and the hydrogen sorption behaviour of th...

  12. Catalytic effect of chlorides compounds on hydrogen sorption properties of magnesium hydride

    Energy Technology Data Exchange (ETDEWEB)

    Conceição, M.O.T. da; Santos, D.S. dos, E-mail: dilson@metalmat.ufrj.br

    2014-12-05

    Highlights: • The NbCl{sub 5} and ZrCl{sub 4} showed to be promising catalysts. • The MgH{sub 2} + 5 wt.% NbCl{sub 5} composite reached the hydrogen capacity of 6.0 wt.% in 6 min. • The MgH{sub 2} + 5 wt.% ZrCl{sub 4} desorbed 6.2 wt.% of H{sub 2} in 4 min. - Abstract: The hydrogen sorption kinetics properties of MgH{sub 2} based composites obtained by mechanical milling were investigated. The composites analyzed in this paper were MgH{sub 2} ball milled with 5 wt.% of NbCl{sub 3}, NbCl{sub 5} and ZrCl{sub 4} chlorides. The samples were investigated using X-ray diffraction, XRD, differential scanning calorimetry, DSC and hydrogen absorption and desorption kinetics tests at 300 and 350 °C. DSC curves showed that the hydrogen desorption peak temperature of all samples milled with catalyst was lower when compared to MgH{sub 2} milled without catalyst. The NbCl{sub 5} catalyzed MgH{sub 2} showed the faster absorption kinetics attaining a total hydrogen capacity of 6 wt.% in 6 min at 300 °C and the sample containing NbCl{sub 3} showed the faster desorption kinetics, desorbing 5.5 wt.% of H{sub 2} in 10 min at 300 °C.

  13. Electromechanical cryocooler

    Science.gov (United States)

    Neufeld, Kenneth W.

    1996-01-01

    An electromechanical cryocooler is disclosed for substantially reducing vibrations caused by the cooler. The direction of the force of the vibrations is measured and a counterforce sufficient to substantially reduce this vibration is calculated and generated. The counterforce is 180.degree. out of phase with the direction of the force of the vibrations.

  14. Acoustic cryocooler

    Science.gov (United States)

    Swift, Gregory W.; Martin, Richard A.; Radenbaugh, Ray

    1990-01-01

    An acoustic cryocooler with no moving parts is formed from a thermoacoustic driver (TAD) driving a pulse tube refrigerator (PTR) through a standing wave tube. Thermoacoustic elements in the TAD are spaced apart a distance effective to accommodate the increased thermal penetration length arising from the relatively low TAD operating frequency in the range of 15-60 Hz. At these low operating frequencies, a long tube is required to support the standing wave. The tube may be coiled to reduce the overall length of the cryocooler. One or two PTR's are located on the standing wave tube adjacent antinodes in the standing wave to be driven by the standing wave pressure oscillations. It is predicted that a heat input of 1000 W at 1000 K will maintian a cooling load of 5 W at 80 K.

  15. In-situ Hydrogen Sorption 2D-ACAR Facility for the Study of Metal Hydrides for Hydrogen Storage

    NARCIS (Netherlands)

    Legerstee, W.J.; De Roode, J.; Anastasopol, A.; Falub, C.V.; Eijt, S.W.H.

    2012-01-01

    We developed a dedicated hydrogen sorption setup coupled to a positron 2D-ACAR (two-dimensional Angular Correlation of Annihilation Radiation) setup employing a 22Na-source, which will enable to collect 2D-ACAR momentum distributions in-situ as a function of temperature, hydrogen pressure and

  16. In-situ Hydrogen Sorption 2D-ACAR Facility for the Study of Metal Hydrides for Hydrogen Storage

    NARCIS (Netherlands)

    Legerstee, W.J.; De Roode, J.; Anastasopol, A.; Falub, C.V.; Eijt, S.W.H.

    2012-01-01

    We developed a dedicated hydrogen sorption setup coupled to a positron 2D-ACAR (two-dimensional Angular Correlation of Annihilation Radiation) setup employing a 22Na-source, which will enable to collect 2D-ACAR momentum distributions in-situ as a function of temperature, hydrogen pressure and hydrog

  17. Pressure cryocooling protein crystals

    Science.gov (United States)

    Kim, Chae Un; Gruner, Sol M.

    2011-10-04

    Preparation of cryocooled protein crystal is provided by use of helium pressurizing and cryocooling to obtain cryocooled protein crystal allowing collection of high resolution data and by heavier noble gas (krypton or xenon) binding followed by helium pressurizing and cryocooling to obtain cryocooled protein crystal for collection of high resolution data and SAD phasing simultaneously. The helium pressurizing is carried out on crystal coated to prevent dehydration or on crystal grown in aqueous solution in a capillary.

  18. Sorption Properties of Iron-Magnesium and Nickel-Magnesium Mg2FeH6 and Mg2NiH4 Hydrides

    Science.gov (United States)

    Matysina, Z. A.; Zaginaichenko, S. Yu.; Shchur, D. V.; Gabdullin, M. T.

    2016-06-01

    Based on molecular-kinetic representations, theory of hydrogen absorption-desorption processes in binary Mg-Fe and Mg-Ni alloys is developed. Free energies of hydrides of these alloys are calculated. Equations of their thermodynamically equilibrium state determining the P-T-c diagrams are derived. A temperature dependence of the desorbed hydrogen concentration is established. A maximal desorption temperature is estimated. The state diagrams determining the concentration dependence of the maximal desorption temperature are constructed. Isopleths and isotherms of hydrogen solubility in the alloys are calculated. The possibility of manifestation of the hysteresis effect in hydrogen solubility isotherms is revealed and the decrease of the width and length of a hysteresis loop with increasing temperature is demonstrated together with the influence of the magnesium hydrate MgH2 in Mg2FeH6 samples and running of chemical reactions on the behavior of the isotherms and the occurrence of bends and jumps in them. All established functional dependences of the sorption properties of the examined alloys are compared with experimental data available from the literature.

  19. Cryogenic microcooling. A micromachined cold stage operating with a sorption compressor in a vapor compression cycle

    Energy Technology Data Exchange (ETDEWEB)

    Burger, J.F.

    2001-01-12

    The development of a micromachined cryocooler was the initial project goal. To make this wide and ambitious goal more specific, the following four project goals were defined: (1) Investigate the opportunities and limitations of the miniaturization of common thermodynamic fluid cooling cycles ('top-down' approach); (2) Investigate how micromechanical techniques and components can be used to build a small cryocooler or cryocooler components ('bottom-up' approach); (3) Choose a cooling cycle that can be used to define specifications for the development of small cooler components; and (4) Develop the necessary components for this demonstrator cooling system and, if possible, combine the components into a working system. Chapter 2 presents an overview of a number of cooling cycles that can be applied in cryocoolers. Emphasis is put on thermodynamic theory, conceptual operation and possible loss mechanisms. This chapter serves as a conceptual framework on cryocooler theory which is referred to throughout this thesis. In chapter 2 also a new regenerative cooling cycle is proposed which appears particularly suitable to be applied on micro-scale. Miniaturization of cryocoolers is discussed in chapter 3. It is divided in three sub-topics: microfabrication, the influence of downscaling on the different fields that play a role in coolers, and the possible miniaturization of the cooling cycles that were discussed in chapter 2. Chapter 4 presents the operation and thermodynamic analysis of a sorption cooler, which consists of a sorption compressor and a Linde-Hampson cold stage. This cooling cycle was chosen for the development of small cooler elements because it appeared suitable to be applied on a small scale. The remainder of the thesis discusses the components that were developed; the requirements for the individual components are based on the specifications of the cooling cycle which are presented in section 4.7. Chapter 5 discusses the operation of a

  20. Understanding the role of few-layer graphene nanosheets in enhancing the hydrogen sorption kinetics of magnesium hydride.

    Science.gov (United States)

    Liu, Guang; Wang, Yijing; Jiao, Lifang; Yuan, Huatang

    2014-07-23

    The catalytic effects of few-layer, highly wrinkled graphene nanosheet (GNS) addition on the dehydrogenation/rehydrogenation performance of MgH2 were investigated. It was found that MgH2-5 wt %GNSs nanocomposites prepared by ball milling exhibit relatively lower sorption temperature, faster sorption kinetics, and more stable cycling performance than that of pure-milled MgH2. The dehydrogenation step confirms that the Avrami exponent n increases from 1.22 to 2.20 by the Johnson-Mehl-Avrami (JMA) formalism when the desorption temperature is reduced from 350 °C to 320 °C and 300 °C, implying that a change in the decomposition temperature can alter the mechanism during the dehydrogenation process. For rehydrogenation, the Avrami value n is close to 1; further study by several models coincident with n = 1 reveals that the absorption process of the MgH2-5 wt %GNSs sample conforms to the Mampel equation formulated through the random nucleation approach and that the nature of the absorption mechanism does not change within the temperature range studied. Furthermore, microstructure analysis demonstrated that the defective GNSs are distributed uniformly among the MgH2 particles and that the grain size of the MgH2-5 wt %GNSs nanocomposite is approximately 5-9 nm. The efficient metal-free catalytic dehydrogenation/rehydrogenation of MgH2 can be attributed to the coupling of the nanosize effect and defective GNSs.

  1. Sorption properties of nanocrystalline metal hydrides for the storage of hydrogen; Sorptionseigenschaften von nanokristallinen Metallhydriden fuer die Wasserstoffspeicherung

    Energy Technology Data Exchange (ETDEWEB)

    Oelerich, W.

    2000-07-01

    For the utilisation of hydrogen in emission-free automobiles new nanostructured Mg-based metal hydrides were developed. These materials show significantly faster absorption and desorption kinetics, which can be even further enhanced by additions of suitable catalysts. Contrary to conventional magnesium powder, hydrogenation at room temperature is demonstrated for the first time. During dehydrogenation at 250 C a desorption rate of 3 to 8 kW/kg with a capacity of 2.5 kWh/kg is achieved, that fulfills the technical requirements for automobile application. (orig.) [German] Im Hinblick auf den Einsatz von Wasserstoff in emissionsfreien Kraftfahrzeugen wurden neuartige nanostrukturierte Metallhydride auf Basis von Magnesium hergestellt. Diese Materialien zeigen eine deutlich schnellere Absorptions- und Desorptionskinetik, die sich durch den Zusatz von geeigneten Katalysatoren noch weiter steigern laesst. Im Gegensatz zu konventionellem Magnesiumpulver konnte erstmals eine Hydrierung bei Raumtemperatur demonstriert werden. Bei der Dehydrierung bei 250 C wird eine Desorptionsrate von 3 bis 8 kW/kg bei einer Kapazitaet von 2,5 kWh/kg erreicht, die die technischen Leistungsanforderungen von Kraftfahrzeugen erfuellt. (orig.)

  2. Complex and liquid hydrides for energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Callini, Elsa; Atakli, Zuleyha Özlem Kocabas; Hauback, Bjørn C.; Orimo, Shin-ichi; Jensen, Craig; Dornheim, Martin; Grant, David; Cho, Young Whan; Chen, Ping; Hjörvarsson, Bjørgvin; de Jongh, Petra; Weidenthaler, Claudia; Baricco, Marcello; Paskevicius, Mark; Jensen, Torben R.; Bowden, Mark E.; Autrey, Thomas S.; Züttel, Andreas

    2016-03-10

    The research on complex hydrides for hydrogen storage was imitated by the discovery of Ti as a hydrogen sorption catalyst in NaAlH4 by Boris Bogdanovic in 1996. A large number of new complex hydride materials in various forms and combinations have been synthesized and characterized and the knowledge on the properties of complex hydrides and the synthesis methods has grown enormously since then. A significant part of the research groups active in the field of complex hydrides are collaborators in the IEA task 32. This paper reports about the important issues in the field of the complex hydride research, i.e. the synthesis of borohydrides, the thermodynamics of complex hydrides and their thermodynamic properties, the effects of size and confinement, the hydrogen sorption mechanism and the complex hydride composites as well as the properties of liquid complex hydrides. This paper is the result of the collaboration of several groups and excellent summary of the recent achievements.

  3. (abstract) JPL Cryocooler Development and Test Program Overview

    Science.gov (United States)

    Ross, R. G.

    1994-01-01

    Many near-term and future space-instrument programs within NASA and the Ballistic Missile Defense Organization (BMDO) depend on the successful development of long-life, low-vibration space cryocoolers. The most demanding near-term programs include a number of science instruments selected for NASA's Earth Observing System (Eos) program, and a number of space reconnaissance instruments associated with the BMDO's Brilliant Eyes program; both of these programs require delivery of similar types of flight coolers in the next few years. To help ensure the success of these cooler commitments, JPL has implemented an extensive cryocooler program in support of the NASA/JPL AIRS project, the Air Force Phillips Laboratory (AFPL), and the Air Force Space and Missiles Systems Division (SMC). This program is directed at assisting industry in developing advanced cryocoolers that successfully address the broad array of complex performance requirements needed for NASA and BMDO long-life space instruments. The JPL cryocooler program includes extensive characterization and life testing of industry-developed cryocoolers, development and flight testing of advanced sorption cooler systems for detector cooling to 10 K , development of mechanical cryocooler enhancement technologies, and flight tests of advanced low-vibration Stirling-cooler systems.

  4. 3rd Cryocooler Conference

    CERN Document Server

    Louie, Berverly; McCarthy, Sandy

    1985-01-01

    Cryocoolers 3 documents the output of the Third Cryocooler Conference, held at the National Bureau of Standards, Boulder, Colorado, on September 17-18, 1984. About 140 people from 10 countries attended the conference representing industry, government, and academia. A total of 26 papers were presented orally at the conference and all appear in written form in the proceedings. The focus of this conference was on small cryocoolers in the temperature range of 4 - 80 K. Mechanical and nonmechanical types are discussed in the various papers. Applications of these small cryocoolers include the cooling of infrared detectors, cryopumps, small superconducting devices and magnets, and electronic devices. The conference proceedings reproduced here was published by the National Bureau of Standards in Boulder, Colorado as NBS Special Publication #698.

  5. International Cryocooler Conference

    CERN Document Server

    Cryocoolers 13

    2005-01-01

    This is the 13th volume in the conference series. Over the years the International Cryocoolers Conference has become the preeminent worldwide conference for the presentation of the latest developments and test experiences with cryocoolers. The typical applications of this technology include cooling space and terrestrial infrared focal plane arrays, space x-ray detectors, medical applications, and a growing number of high-temperature super-capacitor applications.

  6. 17th International Cryocooler Conference

    CERN Document Server

    Ross, Ronald G

    2012-01-01

    Cryocoolers 17 archives developments and performance measurements in the field of cryocoolers based on the contributions of leading international experts at the 17th International Cryocooler Conference that was held in Los Angeles, California, on July 9-12, 2012. The program of this conference consisted of 94 papers; of these, 71 are published here. Over the years the International Cryocoolers Conference has become the preeminent worldwide conference for the presentation of the latest developments and test experiences with cryocoolers. The typical applications of this technology include cooling space and terrestrial infrared focal plane arrays, space x-ray detectors, medical applications, and a growing number of high-temperature superconductor applications.

  7. 16th International Cryocooler Conference

    CERN Document Server

    Ross, Ronald G

    2011-01-01

    Cryocoolers 16 archives developments and performance measurements in the field of cryocoolers based on the contributions of leading international experts at the 16th International Cryocooler Conference that was held in Atlanta, Georgia, on May 17-20, 2010. The program of this conference consisted of 116 papers; of these, 89 are published here. Over the years the International Cryocoolers Conference has become the preeminent worldwide conference for the presentation of the latest developments and test experiences with cryocoolers. The typical applications of this technology include cooling space and terrestrial infrared focal plane arrays, space x-ray detectors, medical applications, and a growing number of high-temperature superconductor applications.

  8. Diaphragm Stirling cryocooler developments

    Science.gov (United States)

    Stacy, W. D.

    1992-01-01

    This paper reports on the status of several ongoing development programs aimed at the demonstration of diaphragm Stirling cycle cryocooler performance. Key attributes of this technology focus on long reliable operating life and excellent efficiency, making it a candidate for cooling of satellite-borne long wavelength sensors for astrophysics and earth observing missions. Three programs are described, each leading to system or component test hardware: a 2 W 65 K single-stage Standard Spacecraft Cryocooler, a 300 mW 30 K two-stage cooler and a 200 mW 4-20 K single-stage cooler. Design features are described, and breadboard experimental data are presented.

  9. 18th International Cryocooler Conference

    CERN Document Server

    Ross, Ronald G

    2014-01-01

    Cryocoolers 18 Cryocoolers 18 archives developments and performance measurements in the field of cryocoolers based on the contributions of leading international experts at the 18th International Cryocooler Conference that was held in Syracuse, New York, on June 9-12, 2014. The program of this conference lead to the 76 peer-reviewed papers that are published here. Over the years the International Cryocoolers Conference has become the preeminent worldwide conference for the presentation of the latest developments and test experiences with cryocoolers. The typical applications of this technology include cooling space and terrestrial infrared focal plane arrays, space x-ray detectors, medical applications, and a growing number of high-temperature superconductor applications.

  10. Destabilization of magnesium hydride through interface engineering

    OpenAIRE

    Mooij, L.P.A.

    2013-01-01

    The aim of this thesis is to study the thermodynamics of hydrogenation of nanoconfined magnesium within a thin film multilayer model system. Magnesium hydride is a potential material for hydrogen storage, which is a key component in a renewable energy system based on hydrogen. In bulk form, magnesium hydride is very stable, which means that hydrogen is released only at elevated temperature. Furthermore, the kinetics of hydrogen sorption is slow, which further hampers the practical use of this...

  11. Relationship between H2 sorption properties and aqueous corrosion mechanisms in A2Ni7 hydride forming alloys (A = Y, Gd or Sm)

    Science.gov (United States)

    Charbonnier, Véronique; Monnier, Judith; Zhang, Junxian; Paul-Boncour, Valérie; Joiret, Suzanne; Puga, Beatriz; Goubault, Lionel; Bernard, Patrick; Latroche, Michel

    2016-09-01

    Intermetallic compounds A2B7 (A = rare earth, B = transition metal) are of interest for Ni-MH batteries. Indeed they are able to absorb hydrogen reversibly and exhibit good specific capacity in electrochemical route. To understand the effect of rare earth on properties of interest such as thermodynamic, cycling stability and corrosion, we synthesized and studied three compounds: Y2Ni7, Gd2Ni7 and Sm2Ni7. Using Sieverts' method, we plot P-c-isotherms up to 10 MPa and study hydride stability upon solid-gas cycling. Electrochemical cycling was also performed, as well as calendar and cycling corrosion study. Corrosion products were characterized by means of X-ray diffraction, electron diffraction, Raman micro-spectroscopy and scanning and transmission electron microscopies. Magnetic measurements were also performed to calculate corrosion rates. A corrosion mechanism, based on the nature of corrosion products, is proposed. By combining results from solid-gas cycling, electrochemical cycling and corrosion study, we attribute the loss in capacity either to corrosion or loss of crystallinity.

  12. 10th International Cryocooler Conference

    CERN Document Server

    2002-01-01

    Cryocoolers 10 is the premier archival publication of the latest advances and performance of small cryogenic refrigerators designed to provide localized cooling for military, space, semi-conductor, medical, computing, and high-temperature superconductor cryogenic applications in the 2-200 K temperature range. Composed of papers written by leading engineers and scientists in the field, Cryocoolers 10 reports the most recent advances in cryocooler development, contains extensive performance test results and comparisons, and relates the latest experience in integrating cryocoolers into advanced applications.

  13. Optical cryocooling of diamond

    Science.gov (United States)

    Kern, M.; Jeske, J.; Lau, D. W. M.; Greentree, A. D.; Jelezko, F.; Twamley, J.

    2017-06-01

    The cooling of solids by optical means only using anti-Stokes emission has a long history of research and achievements. Such cooling methods have many advantages ranging from no moving parts or fluids through to operation in vacuum and may have applications to cryosurgery. However, achieving large optical cryocooling powers has been difficult to manage except in certain rare-earth crystals but these are mostly toxic and not biocompatible. Through study of the emission and absorption cross sections we find that diamond, containing either nitrogen vacancy (NV) or silicon vacancy defects, shows potential for optical cryocooling and, in particular, NV doping shows promise for optical refrigeration. We study the optical cooling of doped diamond microcrystals ranging 10-250 μ m in diameter trapped either in vacuum or in water. For the vacuum case we find NV-doped microdiamond optical cooling below room temperature could exceed |Δ T |>10 K for irradiation powers of Pin<100 mW. We predict that such temperature changes should be easily observed via large alterations in the diffusion constant for optically cryocooled microdiamonds trapped in water in an optical tweezer or via spectroscopic signatures such as the zero-phonon line width or Raman line.

  14. Low-power cryocooler survey

    NARCIS (Netherlands)

    Brake, ter H.J.M.; Wiegerinck, G.F.M.

    2002-01-01

    A cryocooler survey has been performed on data of 235 cryocoolers, with cooling powers below some tens of watts and operating between 4 and 120 K. The state-of-the-art is discussed and trends are investigated on cooling performance, mass and size, cost, lifetime and reliability. The data were compar

  15. 6th International Cryocoolers Conference

    CERN Document Server

    Knox, Margaret

    1991-01-01

    Cryocoolers 6 archives developments and performance measurements in the field of cryocoolers based on the contributions of leading international experts at the 6th International Cryocooler Conference that was held in Plymouth, Massachusetts, on October 25-26, 1990. This year's conference consisted of 54 papers and was sponsored by the David Taylor Naval Ship Research and Development Center of Annapolis, Maryland. The conference proceedings containing 49 submitted manuscripts was published by the David Taylor Naval Ship Research and Development Center in the report reproduced here.

  16. 7th International Cryocooler Conference

    CERN Document Server

    1993-01-01

    Cryocoolers 7 archives developments and performance measurements in the field of cryocoolers based on the contributions of leading international experts at the 7th International Cryocooler Conference which was held in Santa Fe, New Mexico, on November 17-19, 1992. This year's conference consisted of over 100 papers and was hosted by the Nichols Research Corp. and the Air Force Phillips Laboratory of Albuquerque, New Mexico. The conference proceedings were published by the Air Force Phillips Laboratory in the four-volume set reproduced here.

  17. Recent cryocooler progress in Japan

    Science.gov (United States)

    Matsubara, Y.

    1985-05-01

    The progress of cryocoolers and related devices in Japan is reviewed. The Japanese National Railways has developed the light weight 4 K on-board refrigerators since 1977 as part of the MAGLEV train program. Superconducting and cryogenic fundamental technology was examined which included high performance cryocooler, magnetic refrigerator and superfluid refrigeration. Space cryogenics such as the cooling systems of IR-detectors was studied. Cryocooler for special applications such as cryopump, NMR-CT and JJ devices was investigated. Compact heat exchangers, high performance regenerators and reliable compressors are investigated as a critical component technology.

  18. 4th International Cryocoolers Conference

    CERN Document Server

    Patton, George; Knox, Margaret

    1987-01-01

    The Cryocoolers 4 proceedings archives the contributions of leading international experts at the 4th International Cryocooler Conference that was held in Easton, Maryland on September 25-26, 1986. About 170 people attended the conference representing 11 countries, 14 universities, 21 government laboratories and 60 industrial companies. Thirty-one papers were presented describing advancements and applications of cryocoolers in the temperature range below 80K. This year's conference was sponsored by the David Taylor Naval Ship Research and Development Center of Annapolis, Maryland, and the conference proceedings reproduced here was published by them.

  19. 14th International Cryocooler Conference

    CERN Document Server

    Ross, Ronald G

    2007-01-01

    This is the 14th volume in the conference series. Over the years the International Cryocoolers Conference has become the preeminent worldwide conference for the presentation of the latest developments and test experiences with cryocoolers. The typical applications of this technology include cooling space and terrestrial infrared focal plane arrays, space x-ray detectors, medical applications, and a growing number of high-temperature superconductor applications.

  20. 15th International Cryocooler Conference

    CERN Document Server

    Ross, Ronald G

    2009-01-01

    This is the 15th volume in the conference series. Over the years the International Cryocooler Conference has become the preeminent worldwide conference for the presentation of the latest developments and test experiences with cryocoolers. The typical applications of this technology include cooling space and terrestrial infrared focal plane arrays, space x-ray detectors, medical applications, and a growing number of high-temperature superconductor applications.

  1. Novel diaphragm based Stirling cryocooler

    Science.gov (United States)

    Caughley, Alan; Tucker, Alan; Gschwendtner, Michael; Sellier, Mathieu

    2012-06-01

    Industrial Research Ltd has developed a unique diaphragm-based pressure wave generator technology for employment in pulse tube and Stirling cryocoolers. The system uses a pair of metal diaphragms to separate the clean cryocooler gas circuit from a conventionally lubricated mechanical driver, thus producing a clean pressure wave with a long-life drive. We have now extended the same diaphragm concept to support and seal the displacer in a free piston Stirling expander. The diaphragms allow displacer movement without rubbing or clearance gap seals, hence allowing for the development of costeffective long-life and efficient Stirling cryocoolers. Initial modeling, operating in conjunction with a 200 cc swept volume pressure wave generator, predicted in excess of 300 W cooling at 77 K with a Carnot efficiency of over 25%. A proof-of-concept prototype has achieved cryogenic temperatures. Details of the concept, modeling, and testing will be presented.

  2. Boron Hydrides

    Science.gov (United States)

    1946-07-01

    of direct interest could be b.P.4d. ’Thus the discovory of a now proj.ect, since silano is probably too readily infla-zmablo for practical usc’ this...devoted, ho specc4fie compounds vhitih a’-ould be tocdte at prescnt arc: nron tiy * silano , %;2.SiFi3 , diothyl sila~no, (C2 115 )2 Si112, mono r.-rop; ! (n...Bcrohydrido or Li h.... I .A-4A- The prepuation of Silano med of Stannane by the interaction or lithium aluzirun hydride v-ithl silicon tetrtchiorido and

  3. Hydrogenation reaction characteristics and properties of its hydrides for magnetic regenerative material HoCu2

    Institute of Scientific and Technical Information of China (English)

    金滔; 吴梦茜; 黄迦乐; 汤珂; 陈立新

    2016-01-01

    The hydrogenation reaction characteristics and the properties of its hydrides for the magnetic regenerative material HoCu2 (CeCu2-type) of a cryocooler were investigated. The XRD testing reveals that the hydrides of HoCu2 were a mixture of Cu, unknown hydride I, and unknown hydride II. Based on the PCT (pressure−concentration−temperature) curves under different reaction temperatures, the relationships among reaction temperature, equilibrium pressure, and maximum hydrogen absorption capacity were analyzed and discussed. The enthalpy changeΔH and entropy changeΔS as a result of the whole hydrogenation process were also calculated from the PCT curves. The magnetization and volumetric specific heat capacity of the hydride were also measured by SQUID magnetometer and PPMS, respectively.

  4. Cryocoolers for Space

    Science.gov (United States)

    Kittel, Peter; Feller, Jeff; Roach, Pat; Kashani, Ali; Helvensteijn, Ben

    2004-01-01

    Many planetary and Earth science missions require cooling to increase sensitivity and reduce thermal noise of detectors, for preserving high Isp propellants, or for protecting instruments from hostile environments. For space applications, such cooling requires reliable, efficient, long-life coolers that are relatively compact, lightweight, and have low vibration. We have developed and are developing coolers that meet these requirements over a wide range of temperatures. These include pulse tube coolers cooling from 300 K to below 6 K, a magnetic cooler cooling from 10 K to 2 K, a 3He sorption cooler cooling from 2 K to 0.3 K and a helium dilution cooler cooling from 0.3 K to 0.05 K. Details of these coolers and their advantages are presented.

  5. 5th International Conference on Cryocoolers

    CERN Document Server

    1989-01-01

    The Cryocoolers 5 proceedings archives the contributions of leading international experts at the 5th International Cryocooler Conference that was held in Monterey, California on August 18-19, 1988. The authors submitted twenty six papers describing advancements and applications of cryocoolers in the temperature range below 80K. This year's conference was hosted by the U.S. Naval Postgraduate School in Monterey, California, and the conference proceedings reproduced here were published by the Wright-Patterson AFB in Ohio.

  6. Regenerators for Liquid Hydrogen Cryocoolers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future NASA exloration, planetary and astrophysics missions will require various enhancements in multi-stage cryocoolers. These include increased efficiency, reduced...

  7. Regenerators for Liquid Hydrogen Cryocoolers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future NASA exloration, planetary and astrophysics missions will require various enhancements in multi-stage cryocoolers. These include increased efficiency, reduced...

  8. Advanced Hydride Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Motyka, T.

    1989-01-01

    Metal hydrides have been used at the Savannah River Tritium Facilities since 1984. However, the most extensive application of metal hydride technology at the Savannah River Site is being planned for the Replacement Tritium Facility, a $140 million facility schedules for completion in 1990 and startup in 1991. In the new facility, metal hydride technology will be used to store, separate, isotopically purify, pump, and compress hydrogen isotopes. In support of the Replacement Tritium Facility, a $3.2 million, cold,'' process demonstration facility, the Advanced Hydride Laboratory began operation in November of 1987. The purpose of the Advanced Hydride Laboratory is to demonstrate the Replacement Tritium Facility's metal hydride technology by integrating the various unit operations into an overall process. This paper will describe the Advanced Hydride Laboratory, its role and its impact on the application of metal hydride technology to tritium handling.

  9. Advanced Hydride Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Motyka, T.

    1989-12-31

    Metal hydrides have been used at the Savannah River Tritium Facilities since 1984. However, the most extensive application of metal hydride technology at the Savannah River Site is being planned for the Replacement Tritium Facility, a $140 million facility schedules for completion in 1990 and startup in 1991. In the new facility, metal hydride technology will be used to store, separate, isotopically purify, pump, and compress hydrogen isotopes. In support of the Replacement Tritium Facility, a $3.2 million, ``cold,`` process demonstration facility, the Advanced Hydride Laboratory began operation in November of 1987. The purpose of the Advanced Hydride Laboratory is to demonstrate the Replacement Tritium Facility`s metal hydride technology by integrating the various unit operations into an overall process. This paper will describe the Advanced Hydride Laboratory, its role and its impact on the application of metal hydride technology to tritium handling.

  10. Raytheon advanced pulse-tube cryocoolers

    Science.gov (United States)

    Conrad, Ted; Yates, Ryan; Kuo, Daniel; Schaefer, Brian; Arnoult, Matt

    2016-05-01

    Since the 1970s, Raytheon has developed, built, tested and integrated high performance cryocoolers. Our versatile designs for single and multi-stage cryocoolers provide reliable operation for temperatures from 10 to 200 Kelvin with power levels ranging from 50 W to nearly 600 W. These cryocoolers incorporate clearance seals, flexure suspensions, hermetic housings and dynamic balancing to provide long service life and reliable operation in all relevant environments. Recently, Raytheon has developed an advanced regenerator technology capable of operating efficiently at high frequencies and outperforming traditional screen regenerators. The Raytheon Advanced Miniature (RAM-100) cryocooler, a flight packaged, high frequency, single stage pulse tube cooler with an integrated surge volume and inertance tube, has been designed for use with this regenerator. Design details and experimentally measured performance of two iterations of the RAM cryocooler are presented in this paper.

  11. Hydrogen-storing hydride complexes

    Science.gov (United States)

    Srinivasan, Sesha S [Tampa, FL; Niemann, Michael U [Venice, FL; Goswami, D Yogi [Tampa, FL; Stefanakos, Elias K [Tampa, FL

    2012-04-10

    A ternary hydrogen storage system having a constant stoichiometric molar ratio of LiNH.sub.2:MgH.sub.2:LiBH.sub.4 of 2:1:1. It was found that the incorporation of MgH.sub.2 particles of approximately 10 nm to 20 nm exhibit a lower initial hydrogen release temperature of 150.degree. C. Furthermore, it is observed that the particle size of LiBNH quaternary hydride has a significant effect on the hydrogen sorption concentration with an optimum size of 28 nm. The as-synthesized hydrides exhibit two main hydrogen release temperatures, one around 160.degree. C. and the other around 300.degree. C., with the main hydrogen release temperature reduced from 310.degree. C. to 270.degree. C., while hydrogen is first reversibly released at temperatures as low as 150.degree. C. with a total hydrogen capacity of 6 wt. % to 8 wt. %. Detailed thermal, capacity, structural and microstructural properties have been demonstrated and correlated with the activation energies of these materials.

  12. Optimal performance of regenerative cryocoolers

    Science.gov (United States)

    de Boer, P. C. T.

    2011-02-01

    The key component of a regenerative cryocooler is its regenerative heat exchanger. This device is subject to losses due to imperfect heat transfer between the regenerator material and the gas, as well as due to viscous dissipation. The relative magnitudes of these losses can be characterized by the ratio of the Stanton number St to the Fanning friction factor f. Using available data for the ratio St/ f, results are developed for the optimal cooling rate and Carnot efficiency. The variations of pressure and temperature are taken to be sinusoidal in time, and to have small amplitudes. The results are applied to the case of the Stirling cryocooler, with flow being generated by pistons at both sides of the regenerator. The performance is found to be close to optimal at large ratio of the warm space volume to the regenerator void volume. The results are also applied to the Orifice Pulse Tube Refrigerator. In this case, optimal performance additionally requires a large ratio of the regenerator void volume to the cold space volume.

  13. Nanocrystalline Metal Hydrides Obtained by Severe Plastic Deformations

    Directory of Open Access Journals (Sweden)

    Jacques Huot

    2012-01-01

    Full Text Available It has recently been shown that Severe Plastic Deformation (SPD techniques could be used to obtain nanostructured metal hydrides with enhanced hydrogen sorption properties. In this paper we review the different SPD techniques used on metal hydrides and present some specific cases of the effect of cold rolling on the hydrogen storage properties and crystal structure of various types of metal hydrides such as magnesium-based alloys and body centered cubic (BCC alloys. Results show that generally cold rolling is as effective as ball milling to enhance hydrogen sorption kinetics. However, for some alloys such as TiV0.9Mn1.1 alloy ball milling and cold rolling have detrimental effect on hydrogen capacity. The exact mechanism responsible for the change in hydrogenation properties may not be the same for ball milling and cold rolling. Nevertheless, particle size reduction and texture seems to play a leading role in the hydrogen sorption enhancement of cold rolled metal hydrides.

  14. Synthesis of ruthenium hydride

    Science.gov (United States)

    Kuzovnikov, M. A.; Tkacz, M.

    2016-02-01

    Ruthenium hydride was synthesized at a hydrogen pressure of about 14 GPa in a diamond-anvil cell. Energy-dispersive x-ray diffraction was used to monitor the ruthenium crystal structure as a function of hydrogen pressure up to 30 GPa. The hydride formation was accompanied by phase transition from the original hcp structure of the pristine metal to the fcc structure. Our results confirmed the theoretical prediction of ruthenium hydride formation under hydrogen pressure. The standard Gibbs free energy of the ruthenium hydride formation reaction was calculated assuming the pressure of decomposition as the equilibrium pressure.

  15. Thermal Systems (TS): High Capacity Cryocooler Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The 20 Watt, 20 Kelvin cryocooler utilizes the reverse turbo-Brayton thermodynamic cycle to cool helium working gas at cryogenic temperatures, circulated through a...

  16. Nitrogen heat pipe for cryocooler thermal shunt

    Energy Technology Data Exchange (ETDEWEB)

    Prenger, F.C.; Hill, D.D.; Daney, D.E.; Daugherty, M.A. [Los Alamos National Lab., NM (United States); Green, G.F.; Roth, E.W. [Naval Surface Warfare Center, Annapolis, MD (United States)

    1995-09-01

    A nitrogen heat pipe was designed, built and tested for the purpose of providing a thermal shunt between the two stages of a Gifford-McMahan (GM) cryocooler during cooldown. The nitrogen heat pipe has an operating temperature range between 63 and 123 K. While the heat pipe is in the temperature range during the system cooldown, it acts as a thermal shunt between the first and second stage of the cryocooler. The heat pipe increases the heat transfer to the first stage of the cryocooler, thereby reducing the cooldown time of the system. When the heat pipe temperature drops below the triple point, the nitrogen working fluid freezes, effectively stopping the heat pipe operation. A small heat leak between cryocooler stages remains because of axial conduction along the heat pipe wall. As long as the heat pipe remains below 63 K, the heat pipe remains inactive. Heat pipe performance limits were measured and the optimum fluid charge was determined.

  17. Prototype Low Temperature Low Power Cryocooler,

    Science.gov (United States)

    1982-02-01

    4 t CO-other superconducting devices. lLEb In 1977 Dr. Jim Zimmerman of National Bureau of Standards, Boulder, CO described a stirling cycle...Zimmerman successfully operated a point-Contact Nb SQUID on a four- stage stirling cycle cryocooler with a mechanical drive power of approxi- mately 15...allow a complete pressure change in the Cryocooler cylinder (plus expan- ion volume and regenerator ). Since this is not easily accomplished in a

  18. Ultimate Temperature of Pulse Tube Cryocoolers

    Science.gov (United States)

    Kittel, P.

    2010-04-01

    An ideal pulse tube cryocooler using an ideal gas can operate at any temperature. This is not true for real gasses. The enthalpy flow resulting from the real gas effects of 3He, 4He, and their mixtures in ideal pulse tube cryocoolers puts limits on the operating temperature of pulse tube cryocoolers. The discussion of these effects follows a previous description of the real gas effects in ideal pulse tube cryocoolers and makes use of models of the thermophysical properties of 3He and 4He. Published data is used to extend the analysis to mixtures of 3He and 4He. The analysis was done for pressures below 2 MPa and temperatures below 2.5 K. Both gasses and their mixtures show low temperature limits for pulse tube cryocoolers. These limits are in the 0.5-2.2 K range and depend on pressure and mixture. In some circumstances, even lower temperatures may be possible. Pulse tube cryocoolers using the two-fluid properties of dilute 3He in superfluid 4He appear to have no limit.

  19. Hysteresis in Metal Hydrides.

    Science.gov (United States)

    Flanagan, Ted B., And Others

    1987-01-01

    This paper describes a reproducible process where the irreversibility can be readily evaluated and provides a thermodynamic description of the important phenomenon of hysteresis. A metal hydride is used because hysteresis is observed during the formation and decomposition of the hydride phase. (RH)

  20. A review of catalyst-enhanced magnesium hydride as a hydrogen storage material

    Science.gov (United States)

    Webb, C. J.

    2015-09-01

    Magnesium hydride remains an attractive hydrogen storage material due to the high hydrogen capacity and low cost of production. A high activation energy and poor kinetics at practical temperatures for the pure material have driven research into different additives to improve the sorption properties. This review details the development of catalytic additives and their effect on the activation energy, kinetics and thermodynamic properties of magnesium hydride.

  1. 330 W Cryocooler Developments and Testing

    Science.gov (United States)

    Emery, N.; Caughley, A.; Nation, M.; Kimber, A.; Allpress, N.; Reynolds, H.; Boyle, C.; Meier, J.; Tanchon, J.

    2015-12-01

    Fabrum Solutions in association with Callaghan Innovation and Absolut System has developed a 330 W pulse tube cryocooler based on Callaghan Innovation's novel diaphragm pressure wave generators (DPWG). A cost-effective, long life and robust cryocooler has been achieved due to the pulse tube's lack of moving parts and the DPWG's metal diaphragms separating the working gas from the oil lubricated drive mechanism. A 330 cc DPWG was designed and manufactured to run with an inline pulse tube. Absolut System carried out the pulse tube design; manufacture was by Fabrum Solutions, with integration and testing by Callaghan Innovation. The 330 W pulse tubes were run as cryocoolers mounted to 330 cc DPWG's. 480 W of cooling power at 77 K was achieved (target was 330 W at 77 K) from 7kW PV power and 12 kW of electrical input power. An endurance cryocooler was assembled with the left over parts from the optimization exercise. The endurance cryocooler was assembled to run as a liquefier. Calculation showed that 1 litre per hour of liquid nitrogen production was possible from 91 W of cooling power at 83 K. 1 litre per hour of liquid nitrogen was successfully produced for every 100 W of cooling power at 83 K, in a commercial application. Three more 330 W pulse tubes have been mounted to a single 1000 cc DPWG to produce > 1 kW of cooling power at 77 K. The commercialisation of the 1000 W cryocooler is the topic of another paper presented at this conference. Details of the design, development, testing and integration of the 330 W cryocooler are presented in this paper.

  2. Construction and Operation of a 165K Microcooler with a Sorption Compressor and a Micromachined Cold Stage

    NARCIS (Netherlands)

    Burger, Johannes Faas; Holland, Herman J.; ter Brake, Hermanus J.M.; Elwenspoek, Michael Curt; Rogalla, Horst; Ross, R.G. jr

    2003-01-01

    This paper presents the integration and testing of a 165 K microcooler that operates with a sorption compressor and a micromachined cold stage. Attractive features of this combination are the lack of vibration and a long lifetime for a potentially very small cryocooler. The developed cold stage work

  3. Construction and Operation of a 165K Microcooler with a Sorption Compressor and a Micromachined Cold Stage

    NARCIS (Netherlands)

    Burger, J.F.; Holland, H.J.; Brake, ter H.J.M.; Elwenspoek, M.C.; Rogalla, H.; Ross, R.G. jr

    2003-01-01

    This paper presents the integration and testing of a 165 K microcooler that operates with a sorption compressor and a micromachined cold stage. Attractive features of this combination are the lack of vibration and a long lifetime for a potentially very small cryocooler. The developed cold stage work

  4. Construction and Operation of a 165K Microcooler with a Sorption Compressor and a Micromachined Cold Stage

    NARCIS (Netherlands)

    Burger, Johannes Faas; Holland, Herman J.; ter Brake, Hermanus J.M.; Elwenspoek, Michael Curt; Rogalla, Horst; Ross, R.G. jr

    2003-01-01

    This paper presents the integration and testing of a 165 K microcooler that operates with a sorption compressor and a micromachined cold stage. Attractive features of this combination are the lack of vibration and a long lifetime for a potentially very small cryocooler. The developed cold stage

  5. Regenerative Hydride Heat Pump

    Science.gov (United States)

    Jones, Jack A.

    1992-01-01

    Hydride heat pump features regenerative heating and single circulation loop. Counterflow heat exchangers accommodate different temperatures of FeTi and LaNi4.7Al0.3 subloops. Heating scheme increases efficiency.

  6. Regenerative Hydride Heat Pump

    Science.gov (United States)

    Jones, Jack A.

    1992-01-01

    Hydride heat pump features regenerative heating and single circulation loop. Counterflow heat exchangers accommodate different temperatures of FeTi and LaNi4.7Al0.3 subloops. Heating scheme increases efficiency.

  7. Qualification test results for the TIRS cryocooler

    Science.gov (United States)

    Marquardt, Eric; Gully, Wilfred; Marquardt, Jennifer; Boyle, Robert; Hale, Taylor

    2012-06-01

    Ball Aerospace has completed qualification testing of its flight Stirling-cycle mechanical cryocooler for the Thermal Infrared Sensor (TIRS), an instrument slated to fly on the Landsat Data Continuity Mission (LDCM) platform. The TIRS cooler, developed under subcontract to NASA Goddard Space Flight Center, consists of a sophisticated and highly reliable, two-stage, fixed regenerator Stirling cryocooler and its drive electronics. The TIRS cooler provides 2 W of 38 K cooling to the TIRS detectors and 9.8 W shield cooling to 85 K for less than 225 W total input power. Performance test results are reported.

  8. Northrop Grumman Aerospace Systems cryocooler overview

    Science.gov (United States)

    Raab, J.; Tward, E.

    2010-09-01

    Mechanical long life cryocoolers are an enabling technology used to cool a wide variety of detectors in space applications. These coolers provide cooling over a range of temperatures from 2 K to 200 K, cooling powers from tens of mW to tens of watts. Typical applications are missile warning, Earth and climate sciences, astronomy and cryogenic propellant management. Northrop Grumman Aerospace Systems (NGAS) has delivered many of the US flight cooler systems and has 12 long life pulse tube and Stirling coolers on orbit with two having over 11 years of continuous operation. This paper will provide an overview of the NGAS cryocooler capabilities.

  9. Modelling heating effects in cryocooled protein crystals

    CERN Document Server

    Nicholson, J; Fayz, K; Fell, B; Garman, E

    2001-01-01

    With the application of intense X-ray beams from third generation synchrotron sources, damage to cryocooled macromolecular crystals is being observed more commonly . In order to fully utilize synchrotron facilities now available for studying biological crystals, it is essential to understand the processes involved in radiation damage and beam heating so that, if possible, action can be taken to slow the rate of damage. Finite Element Analysis (FEA) has been applied to model the heating effects of X-rays on cryocooled protein crystals, and to compare the relative cooling efficiencies of nitrogen and helium.

  10. Thermodynamic analysis of a thermally operated cascade sorption heat pump for continuous cold generation

    OpenAIRE

    P. Muthukumar, D.V.N. Lakshmi

    2013-01-01

    In this paper, the thermodynamic analysis of a cascade sorption system consists of a two-stage metal hydride heat pump as topping cycle and a single-stage lithium bromide water system as bottom cycle is presented. The effects of various operating temperatures such as driving heat, heat release and refrigeration temperatures, and design parameters such as ratio of metal hydride mass to reactor mass and sensible heat exchange factor on the combined coefficient of performance (COP) of the cascad...

  11. Lightweight hydride storage materials

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, G.J.; Guthrie, S.E.; Bauer, W. [Sandia National Labs., Livermore, CA (United States)

    1995-09-01

    The need for lightweight hydrides in vehicular applications has prompted considerable research into the use of magnesium and its alloys. Although this earlier work has provided some improved performance in operating temperature and pressure, substantial improvements are needed before these materials will significantly enhance the performance of an engineered system on a vehicle. We are extending the work of previous investigators on Mg alloys to reduce the operating temperature and hydride heat of formation in light weight materials. Two important results will be discussed in this paper: (1) a promising new alloy hydride was found which has better pressure-temperature characteristics than any previous Mg alloy and, (2) a new fabrication process for existing Mg alloys was developed and demonstrated. The new alloy hydride is composed of magnesium, aluminum and nickel. It has an equilibrium hydrogen overpressure of 1.3 atm. at 200{degrees}C and a storage capacity between 3 and 4 wt.% hydrogen. A hydrogen release rate of approximately 5 x 10{sup -4} moles-H{sub 2}/gm-min was measured at 200{degrees}C. The hydride heat of formation was found to be 13.5 - 14 kcal/mole-H{sub 2}, somewhat lower than Mg{sub 2}Ni. The new fabrication method takes advantage of the high vapor transport of magnesium. It was found that Mg{sub 2}Ni produced by our low temperature process was better than conventional materials because it was single phase (no Mg phase) and could be fabricated with very small particle sizes. Hydride measurements on this material showed faster kinetic response than conventional material. The technique could potentially be applied to in-situ hydride bed fabrication with improved packing density, release kinetics, thermal properties and mechanical stability.

  12. NASA Space Cryocooler Programs: A 2003 Overview

    Science.gov (United States)

    Ross, R. G., Jr.; Boyle, R. F.; Kittel, P.

    2004-01-01

    Mechanical cryocoolers represent a significant enabling technology for NASA's Earth and Space Science missions. An overview is presented of ongoing cryocooler activities within NASA in support of current flight projects, near-term flight instruments, and long-term technology development. NASA programs in Earth and space science observe a wide range of phenomena, from crop dynamics to stellar birth. Many of the instruments require cryogenic refrigeration to improve dynamic range, extend wavelength coverage, and enable the use of advanced detectors. Although, the largest utilization of coolers over the last decade has been for instruments operating at medium to high cryogenic temperatures (55 to 150 K), reflecting the relative maturity of the technology at these temperatures, important new developments are now focusing at the lower temperature range from 4 to 20 K in support of studies of the origin of the universe and the search for planets around distant stars. NASA's development of a 20K cryocooler for the European Planck spacecraft and its new Advanced Cryocooler Technology Development Program (ACTDP) for 6-18 K coolers are examples of the thrust to provide low temperature cooling for this class of missions.

  13. The 4 K Stirling cryocooler demonstration

    Science.gov (United States)

    Stacy, W. Dodd

    1992-01-01

    This report briefly summarizes the results and conclusions from an SBIR program intended to demonstrate an innovative Stirling cycle cryocooler concept for efficiently lifting heat from 4 K. Refrigeration at 4 K, a temperature useful for superconductors and sensitive instruments, is beyond the reach of conventional regenerative thermodynamic cycles due to the rapid loss of regenerator matrix heat capacity at temperatures below about 20 K. To overcome this fundamental limit, the cryocooler developed under this program integrated three unique features: recuperative regeneration between the displacement gas flow streams of two independent Stirling cycles operating at a 180 degree phase angle, tailored distortion of the two expander volume waveforms from sinusoidal to perfectly match the instantaneous regenerator heat flux from the two cycles and thereby unload the regenerator, and metal diaphragm working volumes to promote near isothermal expansion and compression processes. Use of diaphragms also provides unlimited operating life potential and eliminates bearings and high precision running seals. A phase 1 proof-of-principle experiment demonstrated that counterflow regenerator operation between 77 K and 4 K increases regenerator effectiveness by minimizing metal temperature transient cycling. In phase 2, a detailed design package for a breadboard cryocooler was completed. Fabrication techniques were successfully developed for manufacturing high precision miniature parallel plate recuperators, and samples were produced and inspected. Process development for fabricating suitably flat diaphragms proved more difficult and expensive than anticipated, and construction of the cryocooler was suspended at a completion level of approximately 75%. Subsequent development efforts on other projects have successfully overcome diaphragm fabrication difficulties, and alternate funding is currently being sought for completion and demonstration testing of the 4 K Stirling cryocooler.

  14. Cryocoolers: the state of the art and recent developments.

    Science.gov (United States)

    Radebaugh, Ray

    2009-04-22

    Cryocooler performance and reliability are continually improving. Consequently, they are more and more frequently implemented by physicists in their laboratory experiments or for commercial and space applications. The five kinds of cryocoolers most commonly used to provide cryogenic temperatures for various applications are the Joule-Thomson, Brayton, Stirling, Gifford-McMahon, and pulse tube cryocoolers. Many advances in all types have occurred in the past 20 years that have allowed all of them to be used for a wide variety of applications. The present state of the art and on-going developments of these cryocoolers are reviewed in this paper. In the past five years new research on these cryocoolers has offered the potential to significantly improve them and make them suitable for even more applications. The general trend of this new cryocooler research is also presented.

  15. Hydrogen, lithium, and lithium hydride production

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Sam W.; Spencer, Larry S.; Phillips, Michael R.; Powell, G. Louis; Campbell, Peggy J.

    2017-06-20

    A method is provided for extracting hydrogen from lithium hydride. The method includes (a) heating lithium hydride to form liquid-phase lithium hydride; (b) extracting hydrogen from the liquid-phase lithium hydride, leaving residual liquid-phase lithium metal; (c) hydriding the residual liquid-phase lithium metal to form refined lithium hydride; and repeating steps (a) and (b) on the refined lithium hydride.

  16. High-Efficiency, Low-Temperature Regenerators for Cryocoolers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future NASA planetary and astrophysics missions will require various enhancements in multi-stage cryocoolers. These include increased efficiency, reduced vibration...

  17. Hydrogen storage in sodium aluminum hydride.

    Energy Technology Data Exchange (ETDEWEB)

    Ozolins, Vidvuds; Herberg, J.L. (Lawrence Livermore National Laboratories, Livermore, CA); McCarty, Kevin F.; Maxwell, Robert S. (Lawrence Livermore National Laboratories, Livermore, CA); Stumpf, Roland Rudolph; Majzoub, Eric H.

    2005-11-01

    Sodium aluminum hydride, NaAlH{sub 4}, has been studied for use as a hydrogen storage material. The effect of Ti, as a few mol. % dopant in the system to increase kinetics of hydrogen sorption, is studied with respect to changes in lattice structure of the crystal. No Ti substitution is found in the crystal lattice. Electronic structure calculations indicate that the NaAlH{sub 4} and Na{sub 3}AlH{sub 6} structures are complex-ionic hydrides with Na{sup +} cations and AlH{sub 4}{sup -} and AlH{sub 6}{sup 3-} anions, respectively. Compound formation studies indicate the primary Ti-compound formed when doping the material at 33 at. % is TiAl{sub 3} , and likely Ti-Al compounds at lower doping rates. A general study of sorption kinetics of NaAlH{sub 4}, when doped with a variety of Ti-halide compounds, indicates a uniform response with the kinetics similar for all dopants. NMR multiple quantum studies of solution-doped samples indicate solvent interaction with the doped alanate. Raman spectroscopy was used to study the lattice dynamics of NaAlH{sub 4}, and illustrated the molecular ionic nature of the lattice as a separation of vibrational modes between the AlH{sub 4}{sup -} anion-modes and lattice-modes. In-situ Raman measurements indicate a stable AlH{sub 4}{sup -} anion that is stable at the melting temperature of NaAlH{sub 4}, indicating that Ti-dopants must affect the Al-H bond strength.

  18. From permanent magnets to rechargeable hydride electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Willems, J.J.G.; Buschow, K.H.J.

    1987-02-15

    A brief historical survey is given of how the study of coercitivity mechanisms in SmCo/sub 5/ permanent-magnet materials eventually led to the discovery of the favourable hydrogen sorption properties of the compound LaNi/sub 5/. It is shown how continued research by many investigators dealing with a variety of different physical and chemical properties has resulted in an advanced understanding of some of the principles that govern hydrogen absorption and which are responsible for the changes in physical properties that accompany it. The problems associated with various applications of LaNi/sub 5/-based hydrogen-storage materials are also briefly discussed. A large part of this paper is devoted to the applicability of LaNi/sub 5/-type materials in batteries. Research in this area has resulted in the development of a new type of rechargeable battery: the nickel-hydride cell. This battery can be charged and discharged at high rates and is relatively insensitive to overcharging and overdischarging. Special attention is given to the nature of the electrode degradation process and the effect of composition variations in LaNi/sub 5/-related materials on the lifetime of the corresponding hydride electrodes when subjected to severe electrochemical charge-discharge cycles.

  19. Metal hydrides for lithium-ion batteries.

    Science.gov (United States)

    Oumellal, Y; Rougier, A; Nazri, G A; Tarascon, J-M; Aymard, L

    2008-11-01

    Classical electrodes for Li-ion technology operate via an insertion/de-insertion process. Recently, conversion electrodes have shown the capability of greater capacity, but have so far suffered from a marked hysteresis in voltage between charge and discharge, leading to poor energy efficiency and voltages. Here, we present the electrochemical reactivity of MgH(2) with Li that constitutes the first use of a metal-hydride electrode for Li-ion batteries. The MgH(2) electrode shows a large, reversible capacity of 1,480 mAh g(-1) at an average voltage of 0.5 V versus Li(+)/Li(o) which is suitable for the negative electrode. In addition, it shows the lowest polarization for conversion electrodes. The electrochemical reaction results in formation of a composite containing Mg embedded in a LiH matrix, which on charging converts back to MgH(2). Furthermore, the reaction is not specific to MgH(2), as other metal or intermetallic hydrides show similar reactivity towards Li. Equally promising, the reaction produces nanosized Mg and MgH(2), which show enhanced hydrogen sorption/desorption kinetics. We hope that such findings can pave the way for designing nanoscale active metal elements with applications in hydrogen storage and lithium-ion batteries.

  20. Thermodynamic performance of a laser cryocooler.

    Science.gov (United States)

    Wu, Feng; Chen, Lingen; Wu, Shuang; Sun, Fengrui

    2007-05-28

    The quantum dynamic action of a laser cooling system is analyzed by means of a simplified luminescence center model with ground state and excited state in this paper. The thermodynamic performance of a laser cryocooler is described by solving quantum master equation. The cooling load and the coefficient of performance of the cooler are obtained by using finite time thermodynamics. Some features of the system under the weak coupling and under the intense coupling conditions are discussed.

  1. An Optical Cryostat with $^{3}$He Sorption Refrigerator

    CERN Document Server

    Trofimov, V N; Perminov, V G; Vdovin, V F; Vystavkin, A N

    2005-01-01

    An optical cryostat with $^{3}$He sorption refrigerator is described. The refrigerator is mounted on a copper plate with temperature 4.2 K in vacuum volume of a helium cryostat. It has two sorption steps: the first with working gas $^4$He is intended for condensation of $^{3}$He, the second with $^{3}$He for cooling down to 0.3 K. The cryostat is an independent device that does not contain the external gas communications aimed at reaching low temperatures, and working gases are stored in cans integrated with the cryostat. The refrigerator can be used together with the cryocoolers of Gifford--McMahon or pulse tube types with cooling power not less than 0.3 W/4 K, thus allowing operating without any liquid cryoagents.

  2. Development of Compact 2K GM Cryocoolers

    Science.gov (United States)

    Xu, Mingyao; Bao, Qian; Tsuchiya, Akihiro; Li, Rui

    A compact 2K Gifford-McMahon (GM) cryocooler has been developed for cooling electronic devices, such as Superconducting Single Photo Detectors (SSPD). The heat exchangers, regenerators are optimized with the numerical simulation method developed for 4K GM cryocoolers. After optimizing, the cylinder length is reduced by 85 mm compared with a commercial 0.1W 4K GM cryocooler. With no load on the second stage, a temperature of about 2.1 K has been achieved. With 1 W and 20 mW heat load, the temperature is 44.4 K at the first stage and 2.23 K at the second stage with an input power of about 1.1 kW. And also, it is found that the temperature oscillation decreases as the average temperature decreases. A temperature oscillation of about ±20 mK has been achieved. The object of the project, target specification, and a summary of experiment results will also be introduced in this paper.

  3. Air and metal hydride battery

    Energy Technology Data Exchange (ETDEWEB)

    Lampinen, M.; Noponen, T. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Applied Thermodynamics

    1998-12-31

    The main goal of the air and metal hydride battery project was to enhance the performance and manufacturing technology of both electrodes to such a degree that an air-metal hydride battery could become a commercially and technically competitive power source for electric vehicles. By the end of the project it was possible to demonstrate the very first prototype of the air-metal hydride battery at EV scale, achieving all the required design parameters. (orig.)

  4. Hydrogen Outgassing from Lithium Hydride

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, L N; Schildbach, M A; Smith, R A; Balazs1, B; McLean II, W

    2006-04-20

    Lithium hydride is a nuclear material with a great affinity for moisture. As a result of exposure to water vapor during machining, transportation, storage and assembly, a corrosion layer (oxide and/or hydroxide) always forms on the surface of lithium hydride resulting in the release of hydrogen gas. Thermodynamically, lithium hydride, lithium oxide and lithium hydroxide are all stable. However, lithium hydroxides formed near the lithium hydride substrate (interface hydroxide) and near the sample/vacuum interface (surface hydroxide) are much less thermally stable than their bulk counterpart. In a dry environment, the interface/surface hydroxides slowly degenerate over many years/decades at room temperature into lithium oxide, releasing water vapor and ultimately hydrogen gas through reaction of the water vapor with the lithium hydride substrate. This outgassing can potentially cause metal hydriding and/or compatibility issues elsewhere in the device. In this chapter, the morphology and the chemistry of the corrosion layer grown on lithium hydride (and in some cases, its isotopic cousin, lithium deuteride) as a result of exposure to moisture are investigated. The hydrogen outgassing processes associated with the formation and subsequent degeneration of this corrosion layer are described. Experimental techniques to measure the hydrogen outgassing kinetics from lithium hydride and methods employing the measured kinetics to predict hydrogen outgassing as a function of time and temperature are presented. Finally, practical procedures to mitigate the problem of hydrogen outgassing from lithium hydride are discussed.

  5. Versatile experimental low power 4 K cryocooler

    Science.gov (United States)

    Lambert, N.; Barbanera, S.; Zimmerman, J. E.

    The construction of a low power cryocooler consisting of a five-stage plastic Stirling cooler with an additional Joule-Thomson stage is described. Among its novel features are a contamination-free, pneumatic helium compressor and displacer drive. Valve timing is under computer control. Titanium foil embedded in the cylinder wall reduces helium diffusion through the plastic. The Joule-Thomson stage uses the same low pressure helium as the Stirling stages. The Stirling system cools down below 9 K. The Joule-Thomson stage delivers a few mW cooling at 4.2 K.

  6. AIM cryocooler developments for HOT detectors

    Science.gov (United States)

    Rühlich, I.; Mai, M.; Withopf, A.; Rosenhagen, C.

    2014-06-01

    Significantly increased FPA temperatures for both Mid Wave and Long Wave IR detectors, i.e. HOT detectors, which have been developed in recent years are now leaving the development phase and are entering real application. HOT detectors allowing to push size weight and power (SWaP) of Integrated Detectors Cooler Assemblies (IDCA's) to a new level. Key component mainly driving achievable weight, volume and power consumption is the cryocooler. AIM cryocooler developments are focused on compact, lightweight linear cryocoolers driven by compact and high efficient digital cooler drive electronics (DCE) to also achieve highest MTTF targets. This technology is using moving magnet driving mechanisms and dual or single piston compressors. Whereas SX030 which was presented at SPIE in 2012 consuming less 3 WDC to operate a typical IDCA at 140K, next smaller cooler SX020 is designed to provide sufficient cooling power at detector temperature above 160K. The cooler weight of less than 200g and a total compressor length of 60mm makes it an ideal solution for all applications with limited weight and power budget, like in handheld applications. For operating a typical 640x512, 15μm MW IR detector the power consumption will be less than 1.5WDC. MTTF for the cooler will be in excess of 30,000h and thus achieving low maintenance cost also in 24/7 applications. The SX020 compressor is based on a single piston design with integrated passive balancer in a new design achieves very low exported vibration in the order of 100mN in the compressor axis. AIM is using a modular approach, allowing the chose between 5 different compressor types for one common Stirling expander. The 6mm expander with a total length of 74mm is now available in a new design that fits into standard dewar bores originally designed for rotary coolers. Also available is a 9mm coldfinger in both versions. In development is an ultra-short expander with around 35mm total length to achieve highest compactness. Technical

  7. Investigation of metal hydride nanoparticles templated in metal organic frameworks.

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Benjamin W.; Herberg, Julie L. (Lawrence Livermore National Laboratory, Livermore, CA); Highley, Aaron M.; Grossman, Jeffrey (MIT, Cambridge, MA); Wagner, Lucas (MIT, Cambridge, MA); Bhakta, Raghu; Peaslee, D. (University of Missouri, St. Louis, MO); Allendorf, Mark D.; Liu, X. (University of Missouri, St. Louis, MO); Behrens, Richard, Jr.; Majzoub, Eric H. (University of Missouri, St. Louis, MO)

    2010-11-01

    Hydrogen is proposed as an ideal carrier for storage, transport, and conversion of energy. However, its storage is a key problem in the development of hydrogen economy. Metal hydrides hold promise in effectively storing hydrogen. For this reason, metal hydrides have been the focus of intensive research. The chemical bonds in light metal hydrides are predominantly covalent, polar covalent or ionic. These bonds are often strong, resulting in high thermodynamic stability and low equilibrium hydrogen pressures. In addition, the directionality of the covalent/ionic bonds in these systems leads to large activation barriers for atomic motion, resulting in slow hydrogen sorption kinetics and limited reversibility. One method for enhancing reaction kinetics is to reduce the size of the metal hydrides to nano scale. This method exploits the short diffusion distances and constrained environment that exist in nanoscale hydride materials. In order to reduce the particle size of metal hydrides, mechanical ball milling is widely used. However, microscopic mechanisms responsible for the changes in kinetics resulting from ball milling are still being investigated. The objective of this work is to use metal organic frameworks (MOFs) as templates for the synthesis of nano-scale NaAlH4 particles, to measure the H2 desorption kinetics and thermodynamics, and to determine quantitative differences from corresponding bulk properties. Metal-organic frameworks (MOFs) offer an attractive alternative to traditional scaffolds because their ordered crystalline lattice provides a highly controlled and understandable environment. The present work demonstrates that MOFs are stable hosts for metal hydrides and their reactive precursors and that they can be used as templates to form metal hydride nanoclusters on the scale of their pores (1-2 nm). We find that using the MOF HKUST-1 as template, NaAlH4 nanoclusters as small as 8 formula units can be synthesized inside the pores. A detailed picture of

  8. Analysis of an activated-carbon sorption compressor operating with gas mixtures

    Science.gov (United States)

    Tzabar, N.; Grossman, G.

    2012-10-01

    Sorption compressors elevate the pressure of gases and can provide a more or less continuous mass flow. Unlike mechanical compressors, sorption compressors have no moving parts, and therefore do not emit vibrations and are highly reliable. There exist different sorption compressors for different operating conditions and various gases. However, there are no published reports of sorption compressors for mixed gases. Such compressors, among other applications, may drive mixed-refrigerant Joule-Thomson cryocoolers. The adsorption of mixed gases is usually investigated under steady conditions, mainly for storage and separation processes. However, the sorption process in a compressor goes through varying states and mass changes; therefore, it differs from the common mixed gases adsorption applications. In this research a numerical analysis for mixed gas sorption compressors is developed, based on pure gas adsorption characteristics and the ideal adsorbed solution theory. Two pure gas adsorption models are used for calculating the conditions of the adsorbed phase: Langmuir and Sips; and the Peng-Robinson equation of state is used to calculate the conditions of the vapor phase. Two mixtures are investigated; nitrogen-methane and nitrogen-ethane. Finally, the analysis is verified against experimental results. This research provides initiatory observation for mixed gases sorption compressor in which each component is differently adsorbed.

  9. RICOR development of the next generation highly reliable rotary cryocooler

    Science.gov (United States)

    Regev, Itai; Nachman, Ilan; Livni, Dorit; Riabzev, Sergey; Filis, Avishai; Segal, Victor

    2016-05-01

    Early rotary cryocoolers were designed for the lifetime of a few thousands operating hours. Ricor K506 model's life expectancy was only 5,000 hours, then the next generation K508 model was designed to achieve 10,000 operating hours in basic conditions, while the modern K508N was designed for 20,000 operating hours. Nowadays, the new challenges in the field of rotary cryocoolers require development of a new generation cooler that could compete with the linear cryocooler reliability, achieving the lifetime goal of 30,000 operating hours, and even more. Such new advanced cryocooler can be used for upgrade existing systems, or to serve the new generation of high-temperature detectors that are currently under development, enabling the cryocooler to work more efficiently in the field. The improvement of the rotary cryocooler reliability is based on a deep analysis and understating of the root failure causes, finding solutions to reduce bearings wear, using modern materials and lubricants. All of those were taken into consideration during the development of the new generation rotary coolers. As a part of reliability challenges, new digital controller was also developed, which allows new options, such as discrete control of the operating frequency, and can extend the cooler operating hours due to new controlling technique. In addition, the digital controller will be able to collect data during cryocooler operation, aiming end of life prediction.

  10. Space Flight Qualification Program for the AMS-2 Commercial Cryocoolers

    Science.gov (United States)

    Shirey, K. A.; Banks, I. S.; Breon, S. R.; Boyle, R. F.; Krebs, Carolyn A. (Technical Monitor)

    2002-01-01

    The Alpha Magnetic Spectrometer-02 (AMS-02) experiment is a state-of-the-art particle physics detector containing a large superfluid helium-cooled superconducting magnet. Highly sensitive detector plates inside the magnet measure a particle's speed, momentum, charge, and path. The AMS-02 experiment will study the properties and origin of cosmic particles and nuclei including antimatter and dark matter. AMS-02 will be installed on the International Space Station on Utilization Flight-4. The experiment will be run for at least three years. To extend the life of the stored cryogen and minimize temperature gradients around the magnet, four Stirling-cycle Sunpower M87N cryocoolers will be integrated with AMS-02. The cryocooler cold tip will be connected via a flexible strap to the outer vapor cooled shield of the dewar. Initial thermal analysis shows the lifetime of the experiment is increased by a factor of 2.8 with the use of the cryocooler. The AMS-02 project selected the Sunpower M87 cryocoolers and has asked NASA Goddard to qualify the cryocoolers for space flight use. This paper describes the interfaces with the cryocoolers and presents data collected during testing of the two engineering model cryocoolers. Tests include thermal performance characterization and launch vibration testing. Magnetic field compatibility testing will be presented in a separate paper at the conference.

  11. A high pressure ratio DC compressor for tactical cryocoolers

    Science.gov (United States)

    Chen, Weibo; Cameron, Benjamin H.; Zagarola, Mark V.; Narayanan, Sri R.

    2016-05-01

    A high pressure ratio DC compressor is a critical component for many cryocooler cycles. Prior research has focused on the adaptation of commercial compressor technology (scroll, screw, linear with rectification valves, and regenerative) for use in cryogenic applications where long-life and oil-free (i.e., volatile contamination free) are unique requirements. In addition, many cryocooler applications are for cooling imaging instruments making low vibration an additional requirement. Another candidate compressor technology has emerged from the fuel cell industry. Proton Exchange Membranes (PEMs) are used in fuel cells to separate reactants and transport protons, and these capabilities may be used in cryocoolers to compress hydrogen from low to high pressure. A particular type of PEM utilizing an anhydrous membrane forms the basis of a solid-state cryocooler. Creare has been investigating the use of PEM compressors for low temperature Joule-Thomson and dilution cryocoolers. These cryocoolers have no moving parts, can operate at temperatures down to nominally 23 K, produce no vibration, and are low cost. Our work on the cycle optimization, cryocooler design, and development and demonstration of the compressor technology is the subject of this paper.

  12. Cryocooled Josephson standards for AC voltage metrology

    Science.gov (United States)

    Durandetto, P.; Sosso, A.; Monticone, E.; Trinchera, B.; Fretto, M.; Lacquaniti, V.

    2017-05-01

    The Josephson effect is worldwide used as a basis for constant reference voltages in national metrological institutes and in calibration laboratories of industry. Research on Josephson voltage standards is aiming at a fundamental change also in the metrology of the volt for AC and arbitrary waveforms: programmable Josephson voltage standards converting a digital code into a quantum-accurate stepwise waveform are already available in primary laboratories and even more advanced standards for converting sub-nanosecond binary coded pulses into any arbitrary signal with quantum accuracy are now actively developed and tested. A new experimental setup based on a two-stage Gifford-McMahon cryocooler has been developed at INRiM for the operation of AC-Josephson voltage standards. Among its distinct features, the possibility of employing both the aforementioned techniques (programmable and pulsed Josephson voltage standards) is particularly interesting. Quantum-based AC voltage sine waves have been synthesized with both programmable and pulse-driven arrays, although their accuracy is still limited by thermal oscillations due to the cryocooler piston motion.

  13. Application concepts of small regenerative cryocoolers in superconducting magnet systems

    Science.gov (United States)

    van der Laan, M. T. G.; Tax, R. B.; ten Kate, H. H. J.

    Superconducting magnets are in growing use outside laboratories for example MRI scanners in hospitals. Other applications under development are magnet systems for separation, levitated trains and ship propulsion. The application of cryocoolers can make these systems more practical. Interfacing these cryocoolers to the magnets can be designed in several different ways. The four basic methods will be dealt with. Test results of a realized GM cryocooler-SC magnet system will be shown. It handles about a 1:3 scale MRI magnet of which one of the six coils has been successfully tested at temperatures between 10 and 14 K.

  14. Interface reactions and stability of a hydride composite (NaBH4 + MgH2).

    Science.gov (United States)

    Kato, Shunsuke; Borgschulte, Andreas; Bielmann, Michael; Züttel, Andreas

    2012-06-21

    The use of the interaction of two hydrides is a well-known concept used to increase the hydrogen equilibrium pressure of composite mixtures in comparison to that of pure systems. The thermodynamics and reaction kinetics of such hydride composites are reviewed and experimentally verified using the example NaBH(4) + MgH(2). Particular emphasis is placed on the measurement of the kinetics and stability using thermodesorption experiments and measurements of pressure-composition isotherms, respectively. The interface reactions in the composite reaction were analysed by in situ X-ray photoelectron spectroscopy and by simultaneously probing D(2) desorption from NaBD(4) and H(2) desorption from MgH(2). The observed destabilisation is in quantitative agreement with the calculated thermodynamic properties, including enthalpy and entropy. The results are discussed with respect to kinetic limitations of the hydrogen desorption mechanism at interfaces. General aspects of modifying hydrogen sorption properties via hydride composites are given.

  15. Propellant Conditioning Using Improved Pulse Tube Cryocooler Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Application of the proposed technology (an affordable, large-scale, high-efficiency, low-temperature pulse tube cryocooler system), serves two NASA needs: an...

  16. Highly Effective Thermal Regenerator for Low Temperature Cryocoolers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future missions to investigate the structure and evolution of the universe require highly efficient, low-temperature cryocoolers for low-noise detector systems. We...

  17. A Low Input Power Cryocooler for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future NASA missions will require cryocoolers providing cooling capacities upwards of 0.3W at 35K with heat rejection capability to temperature sinks as low as 150K...

  18. High Pressure Cryocooling of Protein Crystals: The Enigma of Water

    Science.gov (United States)

    Gruner, Sol M.

    2010-03-01

    A novel high-pressure cryocooling technique for preparation biological samples for x-ray analysis is described. The method, high-pressure cryocooling, involves cooling samples to cryogenic temperatures (e.g., 100 K) in high-pressure Helium gas (up to 200 MPa). It bears both similarities and differences to high-pressure cooling methods that have been used to prepare samples for electron microscopy, and has been especially useful for cryocooling of macromolecular crystals for x-ray diffraction. Examples will be given where the method has been effective in providing high quality crystallographic data for difficult samples, such as cases where ligands needed to be stabilized in binding sites to be visualized, or where very high resolution data were required. The talk concludes with a discussion of data obtained by high-pressure cryocooling that pertains to two of the most important problems in modern science: the enigma of water and how water affects the activity of proteins.

  19. Cryocooler With Cold Compressor for Deep Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The unique built-in design features of the proposed mini pulse tube cryocooler avoid all thermal expansion issues enabling it to operate within a cold, 150 K...

  20. A Compact Remote Heat Transfer Device for Space Cryocoolers

    Science.gov (United States)

    Yan, T.; Zhao, Y.; Liang, T.

    In this paper a compact remote heat transfer device (CRHD) for cryocoolers is proposed. This device is especially attractive in cases where cryocoolers are not easy to set near the heat source, generally the infrared sensor. The CRHD is designed on basis of the concept of loop heat pipes, while the primary evaporator is located near the cryocooler cold head and a simple tube-in-tube secondary evaporator is remotely located and thermally connected with the heat source for cooling. With such a device a cooling power of 1 W is achieved across a heat transfer distance of about 2 m. The major problem of this device is the low heat transfer efficiency (1 W of net cooling power at the cost of about 7 W of cooling power from the cryocooler), and in the future a secondary wicked evaporator will be used instead of the tube-in-tube evaporator in order to improve the efficiency.

  1. The third type DC flow in pulse tube cryocooler

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    New phenomena discovered in the experimental research of the ultra-high frequency pulse tube cryocooler were presented.The cause of the new phenomena was analyzed and the third type DC flow was discovered in the pulse tube cryocooler.The third type DC flow not only deteriorated cooling capacity but also led to temperature instability of the pulse tube cryocooler.From the fluid network theory and the simple regenerator model,the root of the third type DC flow was concisely investigated in theory. The asymmetric resistance of oscillating flow in pulse tube cryocooler was the key mechanism of the third type DC flow.Some suppression methods were briefly discussed.

  2. Second Generation Low Cost Cryocooler Electronics (LCCE-2) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The LCCE-2 Program builds off the successes of the USAF "Low Cost Cryocooler Electronics for Space Missions" Program, extending the performance of the developed LCCE...

  3. Applications concepts of small regenerative cryocoolers in superconducitng magnet systems

    NARCIS (Netherlands)

    Laan, van der M.T.G.; Tax, R.B.; Kate, ten H.H.J.

    1992-01-01

    Superconducting magnets are in growing use outside laboratories for example MRI scanners in hospitals. Other applications under development are magnet systems for separation, levitated trains and ship propulsion. The application of cryocoolers can make these systems more practical. Interfacing these

  4. Cryocooler With Cold Compressor for Deep Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation is a high-frequency single-stage pulse tube cryocooler (PTC) that operates at a heat rejection temperature of 150 K. It employs a flexure-bearing...

  5. Second Generation Low Cost Cryocooler Electronics (LCCE-2) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The LCCE-2 Program builds off the successes of the USAF "Low Cost Cryocooler Electronics for Space Missions" Program, extending the performance of the developed LCCE...

  6. Remote actuated cryocooler for superconducting generator and method of assembling the same

    Energy Technology Data Exchange (ETDEWEB)

    Stautner, Ernst Wolfgang; Haran, Kiruba Sivasubramaniam; Fair, Ruben Jeevanasan

    2017-02-14

    In one embodiment, a cryocooler assembly for cooling a heat load is provided. The cryocooler assembly includes a vacuum vessel surrounding the heat load and a cryocooler at least partially inserted into the vacuum vessel, the cryocooler including a coldhead. The assembly further includes an actuator coupled to the cryocooler. The actuator is configured to translate the cryocooler coldhead into thermal engagement with the heat load and to maintain constant pressure of the coldhead against the heat load to facilitate maintaining thermal engagement with the heat load as the heat load shrinks during a cool down process.

  7. An Investigation of Certain Thermodynamic Losses in Minature Cryocoolers

    Science.gov (United States)

    2007-11-02

    Background A Stirling cycle cryocooler can be considered as undergoing an ideal cycle (with Carnot efficiency), with loss processes degrading the...causes no amplitude or start-up distortion (unlike synthesised ‘ reverse time’ inverse filters). 2. Calculate RMS and DC values (from full cycles ). 3...unlimited. 12b. DISTRIBUTION CODE A ABSTRACT (Maximum 200 words) Stirling cycle cryocoolers developed at Oxford have typically been

  8. On-Orbit Performance of the RHESSI Cryocooler

    Science.gov (United States)

    Boyle, Robert F.

    2004-01-01

    The Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spacecraft was launched on February 5,2002. With more than a year of operation on-orbit, its Sunpower M77 cryocooler continues to maintain the array of nine germanium detectors at 7% Trends have begun to emerge in cryocooler power and vibration, suggesting that the cooler's operating point is slowly changing. Possible causes are identified and discussed.

  9. An approach to optimization of low-power Stirling cryocoolers

    Science.gov (United States)

    Sullivan, D. B.; Radebaugh, R.; Daney, D. E.; Zimmerman, J. E.

    1983-01-01

    A method for optimizing the design (shape of the displacer) of low power Stirling cryocoolers relative to the power required to operate the systems is described. A variational calculation which includes static conduction, shuttle and radiation losses, as well as regenerator inefficiency, was completed for coolers operating in the 300 K to 10 K range. While the calculations apply to tapered displacer machines, comparison of the results with stepped displacer cryocoolers indicates reasonable agreement.

  10. Cryocooler applications for high-temperature superconductor magnetic bearings.

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, R. C.

    1998-05-22

    The efficiency and stability of rotational magnetic suspension systems are enhanced by the use of high-temperature superconductor (HTS) magnetic bearings. Fundamental aspects of the HTS magnetic bearings and rotational magnetic suspension are presented. HTS cooling can be by liquid cryogen bath immersion or by direct conduction, and thus there are various applications and integration issues for cryocoolers. Among the numerous cryocooler aspects to be considered are installation; operating temperature; losses; and vacuum pumping.

  11. Catalyzed light hydride nanomaterials embedded in a micro-channels hydrogen storage container.

    Science.gov (United States)

    Dehouche, Zahir; Peretti, Hernán A; Yoo, Yeong; Belkacemi, Khaled; Goyette, Jacques

    2009-01-01

    Activated alloys synthesized by arc-melting were examined as catalysts for improving the hydrogen sorption characteristics of nanostructured magnesium hydride, proposed as a reversible hydrogen storage material. The MgH(2)-catalyst absorbing materials were prepared by ball milling of pure MgH(2) with hydrided Zr(47)Ni(53), Zr(9)Ni(11), and other alloys investigated. The nanostructured MgH(2)-intermetallic systems were tested at 250 degrees C and catalyst addition of eutectoid Zr(47)Ni(53) resulted in the fastest desorption time and highest initial desorption rate. The catalyzed Mg-hydride with activated Zr(9)Ni(11) and Zr(7)Ni(10) phases showed fast desorption kinetics. Moreover, the results demonstrated that the composition of dispersed Zr(x)Ni(y)catalysts has a strong influence on the amount of accumulated hydrogen and desorption rate of Mg-nanocomposite. Part two covers advanced micro-channels hydrogen storage module design based on the results of semi-empirical computer simulations of heat and mass transfers in the container. The micro-channels reservoir concept offers many advantages over the conventional metal hydride hydrogen storage system. It is a micro-structured system that can pack a lot of power into a small space and dissipate effectively the heat of the sorption reactions. This review summarizes recent patents related to CNTS.

  12. Miniature Joule-Thomson cryocooling principles and practice

    CERN Document Server

    Maytal, Ben-Zion

    2013-01-01

    This book is the first in English being entirely dedicated to Miniature Joule-Thomson Cryocooling. The category of Joule-Thomson (JT) cryocoolers takes us back to the roots of cryogenics, in 1895, with figures like Linde and Hampson. The "cold finger" of these cryocoolers is compact, lacks moving parts, and sustains a large heat flux extraction at a steady temperature. Potentially, they cool down unbeatably fast. For example, cooling to below 100 K (minus 173 Celsius) might be accomplished within only a few seconds by liquefying argon. A level of about 120 K can be reached almost instantly with krypton. Indeed, the species of coolant plays a central role dictating the size, the intensity and the level of cryocooling. It is the JT effect that drives these cryocoolers and reflects the deviation of the "real" gas from the ideal gas properties. The nine chapters of the book are arranged in five parts. • The Common Principle of Cyrocoolers shared across the broad variety of cryocooler types • Theoretical Aspec...

  13. Metal Hydride Compression

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Terry A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Bowman, Robert [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Smith, Barton [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Anovitz, Lawrence [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jensen, Craig [Hawaii Hydrogen Carriers LLC, Honolulu, HI (United States)

    2017-07-01

    Conventional hydrogen compressors often contribute over half of the cost of hydrogen stations, have poor reliability, and have insufficient flow rates for a mature FCEV market. Fatigue associated with their moving parts including cracking of diaphragms and failure of seal leads to failure in conventional compressors, which is exacerbated by the repeated starts and stops expected at fueling stations. Furthermore, the conventional lubrication of these compressors with oil is generally unacceptable at fueling stations due to potential fuel contamination. Metal hydride (MH) technology offers a very good alternative to both conventional (mechanical) and newly developed (electrochemical, ionic liquid pistons) methods of hydrogen compression. Advantages of MH compression include simplicity in design and operation, absence of moving parts, compactness, safety and reliability, and the possibility to utilize waste industrial heat to power the compressor. Beyond conventional H2 supplies of pipelines or tanker trucks, another attractive scenario is the on-site generating, pressuring and delivering pure H2 at pressure (≥ 875 bar) for refueling vehicles at electrolysis, wind, or solar generating production facilities in distributed locations that are too remote or widely distributed for cost effective bulk transport. MH hydrogen compression utilizes a reversible heat-driven interaction of a hydride-forming metal alloy with hydrogen gas to form the MH phase and is a promising process for hydrogen energy applications [1,2]. To deliver hydrogen continuously, each stage of the compressor must consist of multiple MH beds with synchronized hydrogenation & dehydrogenation cycles. Multistage pressurization allows achievement of greater compression ratios using reduced temperature swings compared to single stage compressors. The objectives of this project are to investigate and demonstrate on a laboratory scale a two-stage MH hydrogen (H2) gas compressor with a

  14. Erbium hydride decomposition kinetics.

    Energy Technology Data Exchange (ETDEWEB)

    Ferrizz, Robert Matthew

    2006-11-01

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

  15. Hydride development for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, G.J.; Guthrie, S.E.; Bauer, W.; Yang, N.Y.C. [Sandia National Lab., Livermore, CA (United States); Sandrock, G. [SunaTech, Inc., Ringwood, NJ (United States)

    1996-10-01

    The purpose of this project is to develop and demonstrate improved hydride materials for hydrogen storage. The work currently is organized into four tasks: hydride development, bed fabrication, materials support for engineering systems, and IEA Annex 12 activities. At the present time, hydride development is focused on Mg alloys. These materials generally have higher weight densities for storing hydrogen than rare earth or transition metal alloys, but suffer from high operating temperatures, slow kinetic behavior and material stability. The authors approach is to study bulk alloy additions which increase equilibrium overpressure, in combination with stable surface alloy modification and particle size control to improve kinetic properties. This work attempts to build on the considerable previous research in this area, but examines specific alloy systems in greater detail, with attention to known phase properties and structures. The authors have found that specific phases can be produced which have significantly improved hydride properties compared to previous studies.

  16. Metal hydride air conditioner

    Institute of Scientific and Technical Information of China (English)

    YANG; Ke; DU; Ping; LU; Man-qi

    2005-01-01

    The relationship among the hydrogen storage properties, cycling characteristics and thermal parameters of the metal hydride air conditioning systems was investigated. Based on a new alloy selection model, three pairs of hydrogen storage alloys, LaNi4.4 Mn0.26 Al0.34 / La0.6 Nd0.4 Ni4.8 Mn0.2 Cu0. 1, LaNi4.61Mn0. 26 Al0.13/La0.6 Nd0.4 Ni4.8 Mn0.2 Cu0. 1 and LaNi4.61 Mn0.26 Al0.13/La0.6 Y0.4 Ni4.8 Mn0. 2, were selected as the working materials for the metal hydride air conditioning system. Studies on the factors affecting the COP of the system showed that higher COP and available hydrogen content need the proper operating temperature and cycling time,large hydrogen storage capacity, flat plateau and small hysterisis of hydrogen alloys, proper original input hydrogen content and mass ratio of the pair of alloys. It also needs small conditioning system was established by using LaNi4.61 Mn0.26 Al0. 13/La0.6 Y0.4 Ni4.8 Mn0.2 alloys as the working materials, which showed that under the operating temperature of 180℃/40℃, a low temperature of 13℃ was reached, with COP =0.38 and Wnet =0.09 kW/kg.

  17. Geoneutrino and Hydridic Earth model

    CERN Document Server

    Bezrukov, Leonid

    2013-01-01

    Uranium, Thorium and Potassium-40 abundances in the Earth were calculated in the frame of Hydridic Earth model. Terrestrial heat producton from U, Th and K40 decays was calculated also. We must admit the existance of Earth expansion process to understand the obtained large value of terrestrial heat producton. The geoneutrino detector with volume more than 5 kT (LENA type) must be constructed to definitely separate between Bulk Silicat Earth model and Hydridic Earth model.

  18. Sorption properties of wool

    Directory of Open Access Journals (Sweden)

    Radetić Maja M.

    2004-01-01

    Full Text Available Strict ecological legislation, especially in highly developed countries, imposed requirements for the purification of industrial effluents and the need for efficient oil clean up after sea and inland water spills. Although numerous processes have been developed, the application of sorbents is still one of the most efficient methods to remove heavy metal ions, dyes and crude oil from water. Recently, special attention was paid to sorbents based on natural fibres. A review of studies concerning the sorption properties of wool is presented in this paper. The presence of various functional groups on the wool fibre surface contributes to the efficient sorption of heavy metal ions and dyes. A hydrophobic, scaly surface and fibre crimp strongly influence the high sorption capacity of wool for oil. Wool has great sorption potential even as a recycled material. Accordingly, it can be used as a viable substitute to commercially available synthetic sorbents that show poor biodegradab ility.

  19. Physics of hydride fueled PWR

    Science.gov (United States)

    Ganda, Francesco

    The first part of the work presents the neutronic results of a detailed and comprehensive study of the feasibility of using hydride fuel in pressurized water reactors (PWR). The primary hydride fuel examined is U-ZrH1.6 having 45w/o uranium: two acceptable design approaches were identified: (1) use of erbium as a burnable poison; (2) replacement of a fraction of the ZrH1.6 by thorium hydride along with addition of some IFBA. The replacement of 25 v/o of ZrH 1.6 by ThH2 along with use of IFBA was identified as the preferred design approach as it gives a slight cycle length gain whereas use of erbium burnable poison results in a cycle length penalty. The feasibility of a single recycling plutonium in PWR in the form of U-PuH2-ZrH1.6 has also been assessed. This fuel was found superior to MOX in terms of the TRU fractional transmutation---53% for U-PuH2-ZrH1.6 versus 29% for MOX---and proliferation resistance. A thorough investigation of physics characteristics of hydride fuels has been performed to understand the reasons of the trends in the reactivity coefficients. The second part of this work assessed the feasibility of multi-recycling plutonium in PWR using hydride fuel. It was found that the fertile-free hydride fuel PuH2-ZrH1.6, enables multi-recycling of Pu in PWR an unlimited number of times. This unique feature of hydride fuels is due to the incorporation of a significant fraction of the hydrogen moderator in the fuel, thereby mitigating the effect of spectrum hardening due to coolant voiding accidents. An equivalent oxide fuel PuO2-ZrO2 was investigated as well and found to enable up to 10 recycles. The feasibility of recycling Pu and all the TRU using hydride fuels were investigated as well. It was found that hydride fuels allow recycling of Pu+Np at least 6 times. If it was desired to recycle all the TRU in PWR using hydrides, the number of possible recycles is limited to 3; the limit is imposed by positive large void reactivity feedback.

  20. Demonstration of active vibration control on a stirling-cycle cryocooler testbed

    Science.gov (United States)

    Johnson, Bruce G.; Flynn, Frederick J.; Gaffney, Monique S.; Johnson, Dean L.; Ross, Ronald G., Jr.

    1992-01-01

    SatCon Technology Corporation has demonstrated excellent vibration reduction performance using active control on the JPL Stirling-cycle cryocooler testbed. The authors address the use of classical narrowband feedback control to meet the cryocooler vibration specifications using one cryocooler in a self-cancellation configuration. Similar vibration reduction performance was obtained using a cryocooler back-to-back configuration by actively controlling a reaction mass actuator that was used to mimic the second cooler.

  1. Effect of lanthanum hydride on microstructures and hydrogen storage performances of 2LiNH2-MgH2 system

    Institute of Scientific and Technical Information of China (English)

    朱惜林; 韩树民; 赵鑫; 李媛; 刘宝忠

    2014-01-01

    Hydrogen storage properties of 2LiNH2-MgH2 system were improved by adding lanthanum hydride (LaH3), and the role of LaH3 in hydrogen sorption process of Li-Mg-N-H system was investigated. Temperature programmed sorption results showed that the addition of lanthanum hydride reduced the dehydriding/hydriding onset temperature of 2LiNH2-MgH2 system by at least 15 K. Moreover, A 0.053 wt.%/min average rate was determined for the hydrogen desorption of 2LiNH2-MgH2-0.05LaH3 composite, while it was only 0.035 wt.%/min for 2LiNH2-MgH2 system. Hydrogen absorption capacity increased from 1.62 wt.% to 2.12 wt.% within 200 min by adding LaH3 into 2LiNH2-MgH2 system at 383 K. In the dehydrogenation of 2LiNH2-MgH2-0.05LaH3 composite, LaH2 transferred to LaN phase, which reversed to LaH2 in the following hydrogen adsorption process. The reversible reaction of LaH2 ef-fectively promoted the hydrogen sorption of Li-Mg-N-H system. Moreover, the homogenous distribution of fine La hydride was fa-vorable to improving effect of lanthanum hydride.

  2. Enhanced hydrogen storage property of magnesium hydride by high surface area Raney nickel

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, Vinay; Rougier, Aline; Aymard, Luc; Tarascon, Jean-Marie [University of Picardie, Amiens (France); Nazri, Gholam-Abbas [GMR and D, Chemical and Environmental Sciences Lab, Warren, MI (United States)

    2007-12-15

    This paper describes the improvement of hydrogen sorption capacity and kinetics of MgH{sub 2} by addition of high surface area ({approx}100m{sup 2}/g) Raney nickel (RN). Herein, we demonstrate that enhanced hydrogen sorption by MgH{sub 2} due to RN is not only linked to the catalytic nature of Ni, but also correlates well with the BET surface area for the MgH{sub 2}-Ni composites. The Raney Ni also tends to form the less stable Mg{sub 2}NiH{sub 4} hydrides, which desorb hydrogen at much higher pressure as compared with that of the MgH{sub 2}. We have observed a significant improvement in hydrogen sorption capacity and increase in pressure of hydrogen desorption for MgH{sub 2} catalyzed by RN. (author)

  3. Raytheon's next generation compact inline cryocooler architecture

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. [Raytheon Space and Airborne Systems, 2000 E. El Segundo Blvd., El Segundo, CA 90245 (United States)

    2014-01-29

    Since the 1970s, Raytheon has developed, built, tested and integrated high performance cryocoolers. Our versatile designs for single and multi-stage cryocoolers provide reliable operation for temperatures from 10 to 200 Kelvin with power levels ranging from 50 W to nearly 600 W. These advanced cryocoolers incorporate clearance seals, flexure suspensions, hermetic housings and dynamic balancing to provide long service life and reliable operation in all relevant environments. Today, sensors face a multitude of cryocooler integration challenges such as exported disturbance, efficiency, scalability, maturity, and cost. As a result, cryocooler selection is application dependent, oftentimes requiring extensive trade studies to determine the most suitable architecture. To optimally meet the needs of next generation passive IR sensors, the Compact Inline Raytheon Stirling 1-Stage (CI-RS1), Compact Inline Raytheon Single Stage Pulse Tube (CI-RP1) and Compact Inline Raytheon Hybrid Stirling/Pulse Tube 2-Stage (CI-RSP2) cryocoolers are being developed to satisfy this suite of requirements. This lightweight, compact, efficient, low vibration cryocooler combines proven 1-stage (RS1 or RP1) and 2-stage (RSP2) cold-head architectures with an inventive set of warm-end mechanisms into a single cooler module, allowing the moving mechanisms for the compressor and the Stirling displacer to be consolidated onto a common axis and in a common working volume. The CI cryocooler is a significant departure from the current Stirling cryocoolers in which the compressor mechanisms are remote from the Stirling displacer mechanism. Placing all of the mechanisms in a single volume and on a single axis provides benefits in terms of package size (30% reduction), mass (30% reduction), thermodynamic efficiency (>20% improvement) and exported vibration performance (≤25 mN peak in all three orthogonal axes at frequencies from 1 to 500 Hz). The main benefit of axial symmetry is that proven balancing

  4. A New Reducing Regent: Dichloroindium Hydride

    Institute of Scientific and Technical Information of China (English)

    A. BABA; I. SHIBATA; N. HAYASHI

    2005-01-01

    @@ 1Introduction Among the hydride derivatives of group 13 elements, various types of aluminum hydrides and boron hydrides have been employed as powerful reduction tools. Indium hydrides have not received much attention,whereas the synthesis of indium trihydride (InH3) was reported several decades ago[1]. There have been no precedents for monometallic indium hydrides having practical reactivity, while activated hydrides such as an ate complex LiPhn InH4-n (n = 0- 2) and phosphine-coordinated indium hydrides readily reduce carbonyl compounds. In view of this background, we focused on the development of dichloroindium hydrides (Cl2InH) as novel reducing agents that bear characteristic features in both ionic and radical reactions.

  5. Hydride Olefin complexes of tantalum and niobium

    NARCIS (Netherlands)

    Klazinga, Aan Hendrik

    1979-01-01

    This thesis describes investigations on low-valent tantalum and niobium hydride and alkyl complexes, particularly the dicyclopentadienyl tantalum hydride olefin complexes Cp2Ta(H)L (L=olefin). ... Zie: Summary

  6. Cryogenic infrared mission “JAXA/SPICA” with advanced cryocoolers

    Science.gov (United States)

    Spica Working Group; Sugita, Hiroyuki; Nakagawa, Takao; Murakami, Hiroshi; Okamoto, Atsushi; Nagai, Hiroki; Murakami, Masahide; Narasaki, Katsuhiro; Hirabayashi, Masayuki; SPICA Working Group

    2006-02-01

    Since the next cryogenic infrared mission "JAXA/SPICA" employs advanced mechanical cryocoolers with effective radiant cooling in place of cryogen, the primary mirror, 3.5 m in diameter, and the optical bench can be maintained at 4.5 K for at least 5 years. First, the feasibility of the thermal design of the cryogenic system is presented. A 20 K-class Stirling cryocooler was then improved in cooling capacity and reliability for the mission, and the effects of contaminated working gas or new regenerator materials on cooling performance were investigated. Development of a new 3He-JT (Joule-Thomson) cryocooler for use at 1.7 K is also described, along with the successful results of a cooling capacity higher than the required 10 mW. A 4 K-class cryocooler was modified and developed for higher reliability over a five-year operational life and a higher cooling capacity exceeding the current 30 mW. Finally, we discuss a system for heat rejection from cryocoolers using thermal control devices.

  7. High-precision temperature control and stabilization using a cryocooler.

    Science.gov (United States)

    Hasegawa, Yasuhiro; Nakamura, Daiki; Murata, Masayuki; Yamamoto, Hiroya; Komine, Takashi

    2010-09-01

    We describe a method for precisely controlling temperature using a Gifford-McMahon (GM) cryocooler that involves inserting fiber-reinforced-plastic dampers into a conventional cryosystem. Temperature fluctuations in a GM cryocooler without a large heat bath or a stainless-steel damper at 4.2 K are typically of the order of 200 mK. It is particularly difficult to control the temperature of a GM cryocooler at low temperatures. The fiber-reinforced-plastic dampers enabled us to dramatically reduce temperature fluctuations at low temperatures. A standard deviation of the temperature fluctuations of 0.21 mK could be achieved when the temperature was controlled at 4.200 0 K using a feedback temperature control system with two heaters. Adding the dampers increased the minimum achievable temperature from 3.2 to 3.3 K. Precise temperature control between 4.200 0 and 300.000 K was attained using the GM cryocooler, and the standard deviation of the temperature fluctuations was less than 1.2 mK even at 300 K. This technique makes it possible to control and stabilize the temperature using a GM cryocooler.

  8. A vibration free cryostat using pulse tube cryocooler

    Science.gov (United States)

    Wang, Chao; Hartnett, John G.

    2010-05-01

    This paper introduces a new vibration free cryostat cooled by liquid helium and a 4 K pulse tube cryocooler. The cryogenic device mounts on the sample cooling station which is cooled by liquid helium. The boil off helium is recondensed by the pulse tube cryocooler, thus the cryostat maintains zero boil off. There is no mechanical contact between the cryogenic part of the cryocooler and the sample cooling station. A bellows is used to isolate the vibration which could transfer from the cryocooler flange to the cryostat flange at the room temperature. Any vibrations generated by the operation of the cryocooler are almost entirely isolated from the cryogenic device. The cryostat provides a cooling capacity of 0.65 W at 4.21 K on the sample cooling station while maintaining a vapor pressure of 102 kPa. The sample cooling station has a very stable temperature with oscillations of less than ±3 mK during all the operations. A cryogenic microwave oscillator has been successfully cooled and operated with the cryostat.

  9. Helium POT System for Maintaining Sample Temperature after Cryocooler Deactivation

    Science.gov (United States)

    Haid, B. J.

    2006-04-01

    A system for maintaining a sample at a constant temperature below 10 K after deactivating the cooling source is demonstrated. In this system, the cooling source is a 4 K GM cryocooler that is joined with the sample through an extension that consists of a helium pot and a thermal resistance. Upon stopping the cryocooler, the power applied to a heater located on the sample side of the thermal resistance is decreased gradually to maintain an appropriate temperature rise across the thermal resistance as the helium pot warms. The sample temperature is held constant in this manner without the use of solid or liquid cryogens and without mechanically disconnecting the sample from the cooler. Shutting off the cryocooler significantly reduces sample motion that results from vibration and expansion/contraction of the cold-head housing. The reduction in motion permits certain procedures that are very sensitive to sample position stability, but are performed with limited duration. A proof-of-concept system was built and operated with the helium pot pressurized to the cryocooler's charge pressure. A sample with 200 mW of continuous heat dissipation was maintained at 7 K while the cryocooler operated intermittently with a duty cycle of 9.5 minutes off and 20 minutes on.

  10. A high efficiency hybrid stirling-pulse tube cryocooler

    Science.gov (United States)

    Wang, Xiaotao; Zhang, Yibing; Li, Haibing; Dai, Wei; Chen, Shuai; Lei, Gang; Luo, Ercang

    2015-03-01

    This article presented a hybrid cryocooler which combines the room temperature displacers and the pulse tube in one system. Compared with a traditional pulse tube cryocooler, the system uses the rod-less ambient displacer to recover the expansion work from the pulse tube cold end to improve the efficiency while still keeps the advantage of the pulse tube cryocooler with no moving parts at the cold region. In the meantime, dual-opposed configurations for both the compression pistons and displacers reduce the cooler vibration to a very low level. In the experiments, a lowest no-load temperature of 38.5 K has been obtained and the cooling power at 80K was 26.4 W with an input electric power of 290 W. This leads to an efficiency of 24.2% of Carnot, marginally higher than that of an ordinary pulse tube cryocooler. The hybrid configuration herein provides a very competitive option when a high efficiency, high-reliability and robust cryocooler is desired.

  11. A high efficiency hybrid stirling-pulse tube cryocooler

    Directory of Open Access Journals (Sweden)

    Xiaotao Wang

    2015-03-01

    Full Text Available This article presented a hybrid cryocooler which combines the room temperature displacers and the pulse tube in one system. Compared with a traditional pulse tube cryocooler, the system uses the rod-less ambient displacer to recover the expansion work from the pulse tube cold end to improve the efficiency while still keeps the advantage of the pulse tube cryocooler with no moving parts at the cold region. In the meantime, dual-opposed configurations for both the compression pistons and displacers reduce the cooler vibration to a very low level. In the experiments, a lowest no-load temperature of 38.5 K has been obtained and the cooling power at 80K was 26.4 W with an input electric power of 290 W. This leads to an efficiency of 24.2% of Carnot, marginally higher than that of an ordinary pulse tube cryocooler. The hybrid configuration herein provides a very competitive option when a high efficiency, high-reliability and robust cryocooler is desired.

  12. Luminescent properties of aluminum hydride

    Energy Technology Data Exchange (ETDEWEB)

    Baraban, A.P.; Gabis, I.E.; Dmitriev, V.A. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Dobrotvorskii, M.A., E-mail: mstislavd@gmail.com [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Kuznetsov, V.G. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Matveeva, O.P. [National Mineral Resources University, Saint Petersburg 199106 (Russian Federation); Titov, S.A. [Petersburg State University of Railway Transport, Saint-Petersburg 190031 (Russian Federation); Voyt, A.P.; Elets, D.I. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation)

    2015-10-15

    We studied cathodoluminescence and photoluminescence of α-AlH{sub 3}– a likely candidate for use as possible hydrogen carrier in hydrogen-fueled vehicles. Luminescence properties of original α-AlH{sub 3} and α-AlH{sub 3} irradiated with ultraviolet were compared. The latter procedure leads to activation of thermal decomposition of α-AlH{sub 3} and thus has a practical implementation. We showed that the original and UV-modified aluminum hydride contain luminescence centers ‐ structural defects of the same type, presumably hydrogen vacancies, characterized by a single set of characteristic bands of radiation. The observed luminescence is the result of radiative intracenter relaxation of the luminescence center (hydrogen vacancy) excited by electrons or photons, and its intensity is defined by the concentration of vacancies, and the area of their possible excitation. UV-activation of the dehydrogenation process of aluminum hydride leads to changes in the spatial distribution of the luminescence centers. For short times of exposure their concentration increases mainly in the surface regions of the crystals. At high exposures, this process extends to the bulk of the aluminum hydride and ends with a decrease in concentration of luminescence centers in the surface region. - Highlights: • Aluminum hydride contains hydrogen vacancies which serve as luminescence centers. • The luminescence is the result of radiative relaxation of excited centers. • Hydride UV-irradiation alters distribution and concentration of luminescence centers.

  13. Photochemistry of Transition Metal Hydrides.

    Science.gov (United States)

    Perutz, Robin N; Procacci, Barbara

    2016-08-10

    Photochemical reactivity associated with metal-hydrogen bonds is widespread among metal hydride complexes and has played a critical part in opening up C-H bond activation. It has been exploited to design different types of photocatalytic reactions and to obtain NMR spectra of dilute solutions with a single pulse of an NMR spectrometer. Because photolysis can be performed on fast time scales and at low temperature, metal-hydride photochemistry has enabled determination of the molecular structure and rates of reaction of highly reactive intermediates. We identify five characteristic photoprocesses of metal monohydride complexes associated with the M-H bond, of which the most widespread are M-H homolysis and R-H reductive elimination. For metal dihydride complexes, the dominant photoprocess is reductive elimination of H2. Dihydrogen complexes typically lose H2 photochemically. The majority of photochemical reactions are likely to be dissociative, but hydride complexes may be designed with equilibrated excited states that undergo different photochemical reactions, including proton transfer or hydride transfer. The photochemical mechanisms of a few reactions have been analyzed by computational methods, including quantum dynamics. A section on specialist methods (time-resolved spectroscopy, matrix isolation, NMR, and computational methods) and a survey of transition metal hydride photochemistry organized by transition metal group complete the Review.

  14. Metal hydrides: an innovative and challenging conversion reaction anode for lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Luc Aymard

    2015-08-01

    Full Text Available The state of the art of conversion reactions of metal hydrides (MH with lithium is presented and discussed in this review with regard to the use of these hydrides as anode materials for lithium-ion batteries. A focus on the gravimetric and volumetric storage capacities for different examples from binary, ternary and complex hydrides is presented, with a comparison between thermodynamic prediction and experimental results. MgH2 constitutes one of the most attractive metal hydrides with a reversible capacity of 1480 mA·h·g−1 at a suitable potential (0.5 V vs Li+/Li0 and the lowest electrode polarization (2, TiH2, complex hydrides Mg2MHx and other Mg-based hydrides. The reversible conversion reaction mechanism of MgH2, which is lithium-controlled, can be extended to others hydrides as: MHx + xLi+ + xe− in equilibrium with M + xLiH. Other reaction paths—involving solid solutions, metastable distorted phases, and phases with low hydrogen content—were recently reported for TiH2 and Mg2FeH6, Mg2CoH5 and Mg2NiH4. The importance of fundamental aspects to overcome technological difficulties is discussed with a focus on conversion reaction limitations in the case of MgH2. The influence of MgH2 particle size, mechanical grinding, hydrogen sorption cycles, grinding with carbon, reactive milling under hydrogen, and metal and catalyst addition to the MgH2/carbon composite on kinetics improvement and reversibility is presented. Drastic technological improvement in order to the enhance conversion process efficiencies is needed for practical applications. The main goals are minimizing the impact of electrode volume variation during lithium extraction and overcoming the poor electronic conductivity of LiH. To use polymer binders to improve the cycle life of the hydride-based electrode and to synthesize nanoscale composite hydride can be helpful to address these drawbacks. The development of high-capacity hydride anodes should be inspired by the emergent

  15. Metal hydrides: an innovative and challenging conversion reaction anode for lithium-ion batteries.

    Science.gov (United States)

    Aymard, Luc; Oumellal, Yassine; Bonnet, Jean-Pierre

    2015-01-01

    The state of the art of conversion reactions of metal hydrides (MH) with lithium is presented and discussed in this review with regard to the use of these hydrides as anode materials for lithium-ion batteries. A focus on the gravimetric and volumetric storage capacities for different examples from binary, ternary and complex hydrides is presented, with a comparison between thermodynamic prediction and experimental results. MgH2 constitutes one of the most attractive metal hydrides with a reversible capacity of 1480 mA·h·g(-1) at a suitable potential (0.5 V vs Li(+)/Li(0)) and the lowest electrode polarization (hydrides Mg2MH x and other Mg-based hydrides. The reversible conversion reaction mechanism of MgH2, which is lithium-controlled, can be extended to others hydrides as: MH x + xLi(+) + xe(-) in equilibrium with M + xLiH. Other reaction paths-involving solid solutions, metastable distorted phases, and phases with low hydrogen content-were recently reported for TiH2 and Mg2FeH6, Mg2CoH5 and Mg2NiH4. The importance of fundamental aspects to overcome technological difficulties is discussed with a focus on conversion reaction limitations in the case of MgH2. The influence of MgH2 particle size, mechanical grinding, hydrogen sorption cycles, grinding with carbon, reactive milling under hydrogen, and metal and catalyst addition to the MgH2/carbon composite on kinetics improvement and reversibility is presented. Drastic technological improvement in order to the enhance conversion process efficiencies is needed for practical applications. The main goals are minimizing the impact of electrode volume variation during lithium extraction and overcoming the poor electronic conductivity of LiH. To use polymer binders to improve the cycle life of the hydride-based electrode and to synthesize nanoscale composite hydride can be helpful to address these drawbacks. The development of high-capacity hydride anodes should be inspired by the emergent nano-research prospects which

  16. Size effects on miniature Stirling cycle cryocoolers

    Science.gov (United States)

    Yang, Xiaoqin; Chung, J. N.

    2005-08-01

    Size effects on the performance of Stirling cycle cryocoolers were investigated by examining each individual loss associated with the regenerator and combining these effects. For the fixed cycle parameters and given regenerator length scale, it was found that only for a specific range of the hydrodynamic diameter the system can produce net refrigeration and there is an optimum hydraulic diameter at which the maximum net refrigeration is achieved. When the hydraulic diameter is less than the optimum value, the regenerator performance is controlled by the pressure drop loss; when the hydraulic diameter is greater than the optimum value, the system performance is controlled by the thermal losses. It was also found that there exists an optimum ratio between the hydraulic diameter and the length of the regenerator that offers the maximum net refrigeration. As the regenerator length is decreased, the optimum hydraulic diameter-to-length ratio increases; and the system performance is increased that is controlled by the pressure drop loss and heat conduction loss. Choosing appropriate regenerator characteristic sizes in small-scale systems are more critical than in large-scale ones.

  17. Size effects on miniature Stirling cycle cryocoolers

    Energy Technology Data Exchange (ETDEWEB)

    Xiaoqin Yang; Chung, J.N. [Florida Univ., Dept. of Mechanical and Aerospace Engineering, Gainesville, FL (United States)

    2005-08-01

    Size effects on the performance of Stirling cycle cryocoolers were investigated by examining each individual loss associated with the regenerator and combining these effects. For the fixed cycle parameters and given regenerator length scale, it was found that only for a specific range of the hydrodynamic diameter the system can produce net refrigeration and there is an optimum hydraulic diameter at which the maximum net refrigeration is achieved. When the hydraulic diameter is less than the optimum value, the regenerator performance is controlled by the pressure drop loss; when the hydraulic diameter is greater than the optimum value, the system performance is controlled by the thermal losses. It was also found that there exists an optimum ratio between the hydraulic diameter and the length of the regenerator that offers the maximum net refrigeration. As the regenerator length is decreased, the optimum hydraulic diameter-to-length ratio increases; and the system performance is increased that is controlled by the pressure drop loss and heat conduction loss. Choosing appropriate regenerator characteristic sizes in small-scale systems are more critical than in large-scale ones. (Author)

  18. Colouring cryo-cooled crystals: online microspectrophotometry

    Energy Technology Data Exchange (ETDEWEB)

    McGeehan, John [EMBL, 6 rue Jules Horowitz, 38042 Grenoble (France); Biophysics Laboratories, School of Biological Sciences, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth PO1 2DY (United Kingdom); Ravelli, Raimond B. G., E-mail: ravelli@lumc.nl [EMBL, 6 rue Jules Horowitz, 38042 Grenoble (France); Section Electron Microscopy, Department of Molecular Cell Biology, Leiden University Medical Center (LUMC), PO Box 9600, 2300RC Leiden (Netherlands); Murray, James W. [Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom); Imperial College, Exhibition Road, London SW7 2AZ (United Kingdom); Owen, Robin Leslie [Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom); Cipriani, Florent [EMBL, 6 rue Jules Horowitz, 38042 Grenoble (France); McSweeney, Sean [ESRF, 6 rue Jules Horowitz, 38043 Grenoble (France); Weik, Martin [Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale, Jean Pierre EBEL, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1 (France); Garman, Elspeth F., E-mail: ravelli@lumc.nl [Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom)

    2009-03-01

    A portable and readily aligned online microspectrophotometer that can be easily installed on macromolecular crystallography beamlines is described. It allows measurement of the spectral characteristics of macromolecular crystals prior, during, and after the X-ray diffraction experiment. X-rays can produce a high concentration of radicals within cryo-cooled macromolecular crystals. Some radicals have large extinction coefficients in the visible (VIS) range of the electromagnetic spectrum, and can be observed optically and spectrally. An online microspectrophotometer with high temporal resolution has been constructed that is capable of measuring UV/VIS absorption spectra (200–1100 nm) during X-ray data collection. The typical X-ray-induced blue colour that is characteristic of a wide range of cryo-conditions has been identified as trapped solvated electrons. Disulphide-containing proteins are shown to form disulphide radicals at millimolar concentrations, with absorption maxima around 400 nm. The solvated electrons and the disulphide radicals seem to have a lifetime in the range of seconds up to minutes at 100 K. The temperature dependence of the kinetics of X-ray-induced radical formation is different for the solvated electrons compared with the disulphide radicals. The online microspectrophotometer provides a technique complementary to X-ray diffraction for analysing and characterizing intermediates and redox states of proteins and enzymes.

  19. Method of producing a chemical hydride

    Science.gov (United States)

    Klingler, Kerry M.; Zollinger, William T.; Wilding, Bruce M.; Bingham, Dennis N.; Wendt, Kraig M.

    2007-11-13

    A method of producing a chemical hydride is described and which includes selecting a composition having chemical bonds and which is capable of forming a chemical hydride; providing a source of a hydrocarbon; and reacting the composition with the source of the hydrocarbon to generate a chemical hydride.

  20. Hydrogen, lithium, and lithium hydride production

    Science.gov (United States)

    Brown, Sam W; Spencer, Larry S; Phillips, Michael R; Powell, G. Louis; Campbell, Peggy J

    2014-03-25

    A method of producing high purity lithium metal is provided, where gaseous-phase lithium metal is extracted from lithium hydride and condensed to form solid high purity lithium metal. The high purity lithium metal may be hydrided to provide high purity lithium hydride.

  1. Multimodal tuned dynamic absorber for split Stirling linear cryocooler

    Science.gov (United States)

    Veprik, Alexander; Tuito, Avi

    2016-05-01

    Low size, weight, power and price split Stirling linear cryocooler usually comprises electro-dynamically driven compressor and pneumatically driven expander which are side-by-side fixedly mounted upon the common frame and interconnected by the configurable transfer line. Vibration export produced by such a cryocooler comprises of a pair of tonal forces, the frequency of which essentially equals fixed driving frequency. In vibration sensitive applications, this may result in excessive angular line of sight jitter and translational defocusing affecting the image quality. The authors present Multimodal Tuned Dynamic Absorber, having one translational and two tilting modes essentially tuned to the driving frequency. Dynamic analysis shows that the dynamic reactions (force and moment) produced by such a dynamic absorber are capable of simultaneous attenuation of translational and tilting components of cryocooler induced vibration. The authors reveal the preferable design, the method of fine tuning and outcomes of numerical simulation on attainable performance.

  2. Cryogenic performance of a cryocooler-cooled superconducting undulator

    Energy Technology Data Exchange (ETDEWEB)

    Fuerst, J. D.; Doose, C.; Hasse, Q.; Ivanyushenkov, Y.; Kasa, M.; Shiroyanagi, Y. [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2014-01-29

    A cryocooler-cooled superconducting undulator has been installed and operated with beam at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The device consists of a dual-core 42-pole magnet structure that is cooled to 4.2 K with a system of four cryocoolers operating in a zero-boil-off configuration. This effort represents the culmination of a development program to establish concept feasibility and evaluate cryostat design and cryocooler-based refrigeration. Cryostat performance is described including cool-down/warm-up, steady-state operation, cooling margin, and the impact of beam during operation in the APS storage ring. Plans for future devices with longer magnets, which will incorporate lessons learned from the development program, are also discussed.

  3. The third type DC flow in pulse tube cryocooler

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yuan; GU Chao; CAI HuiKun

    2009-01-01

    New phenomena discovered in the experimental research of the ultra-high frequency pulse tube cryo cooler were presented.The cause of the new phenomena was analyzed and the third type DC flow was discovered in the pulse tube cryocooler.The third type DC flow not only deteriorated cooling capacity but also led to temperature instability of the pulse tube cryocooler.From the fluid network theory and the simple regenerator model,the root of the third type DC flow was concisely investigated in theory.The asymmetric resistance of oscillating flow in pulse tube cryocooler was the key mechanism of the third type DC flow.Some suppression methods were briefly discussed.

  4. Study of the minimum refrigeration temperature of regenerative cryocoolers

    Science.gov (United States)

    Chen, Guangming; Chen, Guobang; Yu, Jianping

    Based on the principles of thermodynamics, the relation between the isentropic expansion coefficient μs and the isobaric specific heat Cp has been found. The values of μs at different temperatures and pressures are calculated. From theoretical and experimental values of Cp of helium in the supercritical area, the minimum refrigeration temperature which may be reached by traditional regenerative cryocoolers is theoretically demonstrated. It is pointed out that this boundary is just the lambda line of helium. In order to obtain temperatures lower than the lambda line, a new type of regenerative cryocooler which can work in the helium II region is proposed. The working principle, schematic diagram and theoretical refrigeration temperature of this new cryocooler are discussed.

  5. Raytheon RSP2 Cryocooler Low Temperature Testing and Design Enhancements

    Science.gov (United States)

    Hon, R. C.; Kirkconnell, C. S.; Shrago, J. A.

    2010-04-01

    The High Capacity Raytheon Stirling/Pulse Tube Hybrid 2-Stage cryocooler (HC-RSP2) was originally developed to provide simultaneous cooling at temperatures of 85 K and 35 K. During testing performed in 2008 it was demonstrated that this stock-configuration cryocooler is capable of providing significant amounts of heat lift at 2nd stage temperatures as low as 12 K, and modeling indicated that minor changes to the 2nd stage inertance tube/surge volume setup could yield improved performance. These changes were implemented and the cooler was successfully retested, producing >350 mW of heat lift at 12 K. A comprehensive redesign of the system has been performed, the result of which is a robust 2-stage cryocooler system that is intended to efficiently produce relatively large amounts of cooling at 2nd stage temperatures system redesign. Expected performance, mass and packaging volume are addressed.

  6. Anodematerials for Metal Hydride Batteries

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf

    1997-01-01

    This report describes the work on development of hydride forming alloys for use as electrode materials in metal hydride batteries. The work has primarily been concentrated on calcium based alloys derived from the compound CaNi5. This compound has a higher capacity compared with alloys used in today......’s hydride batteries, but a much poorer stability towards repeated charge/discharge cycling. The aim was to see if the cycleability of CaNi5 could be enhanced enough by modifications to make the compound a suitable electrode material. An alloying method based on mechanical alloying in a planetary ball mill...... by annealing at 700°C for 12 hours. The alloys appeared to be nanocrystalline with an average crystallite size around 10 nm before annealing. Special steel containers was developed for the annealing of the metal powders in inert atmosphere. The use of various annealing temperatures was investigated...

  7. CFD analysis of a diaphragm free-piston Stirling cryocooler

    Science.gov (United States)

    Caughley, Alan; Sellier, Mathieu; Gschwendtner, Michael; Tucker, Alan

    2016-10-01

    This paper presents a Computational Fluid Dynamics (CFD) analysis of a novel free-piston Stirling cryocooler that uses a pair of metal diaphragms to seal and suspend the displacer. The diaphragms allow the displacer to move without rubbing or moving seals. When coupled to a metal diaphragm pressure wave generator, the system produces a complete Stirling cryocooler with no rubbing parts in the working gas space. Initial modelling of this concept using the Sage modelling tool indicated the potential for a useful cryocooler. A proof-of-concept prototype was constructed and achieved cryogenic temperatures. A second prototype was designed and constructed using the experience gained from the first. The prototype produced 29 W of cooling at 77 K and reached a no-load temperature of 56 K. The diaphragm's large diameter and short stroke produces a significant radial component to the oscillating flow fields inside the cryocooler which were not modelled in the one-dimensional analysis tool Sage that was used to design the prototypes. Compared with standard pistons, the diaphragm geometry increases the gas-to-wall heat transfer due to the higher velocities and smaller hydraulic diameters. A Computational Fluid Dynamics (CFD) model of the cryocooler was constructed to understand the underlying fluid-dynamics and heat transfer mechanisms with the aim of further improving performance. The CFD modelling of the heat transfer in the radial flow fields created by the diaphragms shows the possibility of utilizing the flat geometry for heat transfer, reducing the need for, and the size of, expensive heat exchangers. This paper presents details of a CFD analysis used to model the flow and gas-to-wall heat transfer inside the second prototype cryocooler, including experimental validation of the CFD to produce a robust analysis.

  8. Hydrogen Storage in Metal Hydrides

    Science.gov (United States)

    1990-08-01

    Hydrogen Storage Capacity Hydride by weight (%) [1) by volume (g/ml) [2] MgH2 7.00 0.101 Mg2NiH4 3.84 0,081 Mg2CuH4 2.04 - - 27 ...Include Security Classification) Hydrogen Storage in Metal Hydrides (U) 12. PERSONAL AUTHOR(S) DelaRosa, Mark J. 13a. TYPE OF REPORT 13b. TIME...objective of this program was to develop an economical process for pr-ducing a lightweight hydrogen storage medium by the chemical vapor infiltration

  9. Sub-millikelvin stabilization of a closed cycle cryocooler.

    Science.gov (United States)

    Dubuis, Guy; He, Xi; Božović, Ivan

    2014-10-01

    Intrinsic temperature oscillations (with the amplitude up to 1 K) of a closed cycle cryocooler are stabilized by a simple thermal damping system. It employs three different materials with different thermal conductivity and specific heat at various temperatures. The amplitude of oscillations of the sample temperature is reduced to less than 1 mK, in the temperature range from 4 K to 300 K, while the cooling power is virtually undiminished. The damping system is small, inexpensive, can be retrofitted to most existing closed cycle cryocoolers, and may improve measurements of any temperature-sensitive physics properties.

  10. Recent development status of compact 2 K GM cryocoolers

    Science.gov (United States)

    Bao, Q.; Xu, M. Y.; Tsuchiya, A.; Li, R.

    2015-12-01

    To meet the growing demand for a compact cooling solution for superconducting electronic devices, we developed a two-stage 2 K GM cryocooler and a cryostat system, which can reach 46.3 K / 2.2 K on the first and second stages under no-load conditions. Nevertheless, with several innovative technologies applied, the total length of the expander cylinder is reduced to under 70% of the smallest conventional 4 K GM cryocooler. In this paper we will present the design method, including material selection and structure design with detailed explanation, which has been confirmed by both simulation and experiment.

  11. Crystallography of shear transformations in zirconium hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Cassidy, Michael Philip [Univ. of Illinois, Urbana-Champaign, IL (United States)

    1978-01-01

    The crystallography and substructure of the transformations which have been hypothesized as involving a martensitic shear, and which occur between zirconium hydrides were investigated. Specifically, the formation of gamma zirconium hydride from delta hydride and the delta hydride to epsilon hydride transformation were studied. The habit planes, orientation relationships, lattice invariant shears, and interface structures were determined by transmission electron microscopy and diffraction. Surface tilts were observed and measured with an interference microscope. The direction and magnitude of the shape strain produced by the formation of gamma were determined by the measurement of fiducial scratch displacements. These results were compared with the phenomenological crystallographic theory of martensitic transformations.

  12. Characteristics and Applications of Metal Hydrides

    Science.gov (United States)

    Egan, G. J.; Lynch, F. E.

    1987-01-01

    Report discusses engineering principles of uses of metal hydrides in spacecraft. Metal hydrides absorb, store, pump, compress, and expand hydrogen gas. Additionally, they release or absorb sizeable amounts of heat as they form and decompose - property adapted for thermal-energy management or for propulsion. Describes efforts to: Identify heat sources and sinks suitable for driving metal hydride thermal cycles in spacecraft; develop concepts for hydride subsystems employing available heating and cooling methods; and produce data base on estimated sizes, masses, and performances of hydride devices for spacecraft.

  13. On the possible cycles via the unified perspective of cryocoolers. Part A: The Joule-Thomson cryocooler

    Energy Technology Data Exchange (ETDEWEB)

    Maytal, Ben-Zion [Rafael, Ltd., P.O. Box 2250, Haifa 3102102 (Israel); Pfotenhauer, John M. [University of Wisconsin-Madison, Madison, WI 53706 (United States)

    2014-01-29

    Joule-Thomson (JT) cryocoolers possess a self adjusting effect, which preserves the state of the returning stream from the evaporator as a saturated vapor. The heat load can be entirely absorbed at constant temperature by evaporation even for different sized heat exchangers. It is not possible for the steady state flow resulting from a gradual cool down to penetrate 'deeper' into the two-phase dome, and produce a two phase return flow even with a heat exchanger of unlimited size. Such behavior was implicitly taken for granted in the literature but never clearly stated nor questioned and therefore never systematically proven. The discussion provided below provides such a proof via the unified model of cryocoolers. This model portrays all cryocoolers as magnifiers of their respective elementary temperature reducing mechanism through the process of 'interchanging'.

  14. Characterization of hydrides and delayed hydride cracking in zirconium alloys

    Science.gov (United States)

    Fang, Qiang

    This thesis tries to fill some of the missing gaps in the study of zirconium hydrides with state-of-art experiments, cutting edge tomographical technique, and a novel numerical algorithm. A new hydriding procedure is proposed. The new anode material and solution combination overcomes many drawbacks of the AECLRTM hydriding method and leads to superior hydriding result compared to the AECL RTM hydriding procedure. The DHC crack growth velocity of as-received Excel alloy and Zr-2.5Nb alloy together with several different heat treated Excel alloy samples are measured. While it already known that the DHC crack growth velocity increases with the increase of base metal strength, the finding that the transverse plane is the weaker plane for fatigue crack growth despite having higher resistance to DHC crack growth was unexpected. The morphologies of hydrides in a coarse grained Zircally-2 sample have been studied using synchrotron x-rays at ESRF with a new technique called Diffraction Contrast Tomography that uses simultaneous collection of tomographic data and diffraction data to determine the crystallographic orientation of crystallites (grains) in 3D. It has been previously limited to light metals such as Al or Mg (due to the use of low energy x-rays). Here we show the first DCT measurements using high energy x-rays (60 keV), allowing measurements in zirconium. A new algorithm of a computationally effcient way to characterize distributions of hydrides - in particular their orientation and/or connectivity - has been proposed. It is a modification of the standard Hough transform, which is an extension of the Hough transform widely used in the line detection of EBSD patterns. Finally, a basic model of hydrogen migration is built using ABAQUS RTM, which is a mature finite element package with tested modeling modules of a variety of physical laws. The coupling of hydrogen diffusion, lattice expansion, matrix deformation and phase transformation is investigated under

  15. Metal hydride hydrogen compression: recent advances and future prospects

    Science.gov (United States)

    Yartys, Volodymyr A.; Lototskyy, Mykhaylo; Linkov, Vladimir; Grant, David; Stuart, Alastair; Eriksen, Jon; Denys, Roman; Bowman, Robert C.

    2016-04-01

    Metal hydride (MH) thermal sorption compression is one of the more important applications of the MHs. The present paper reviews recent advances in the field based on the analysis of the fundamental principles of this technology. The performances when boosting hydrogen pressure, along with two- and three-step compression units, are analyzed. The paper includes also a theoretical modelling of a two-stage compressor aimed at describing the performance of the experimentally studied systems, their optimization and design of more advanced MH compressors. Business developments in the field are reviewed for the Norwegian company HYSTORSYS AS and the South African Institute for Advanced Materials Chemistry. Finally, future prospects are outlined presenting the role of the MH compression in the overall development of the hydrogen-driven energy systems. The work is based on the analysis of the development of the technology in Europe, USA and South Africa.

  16. Properties of nanoscale metal hydrides.

    Science.gov (United States)

    Fichtner, Maximilian

    2009-05-20

    Nanoscale hydride particles may exhibit chemical stabilities which differ from those of a macroscopic system. The stabilities are mainly influenced by a surface energy term which contains size-dependent values of the surface tension, the molar volume and an additional term which takes into account a potential reduction of the excess surface energy. Thus, the equilibrium of a nanoparticular hydride system may be shifted to the hydrogenated or to the dehydrogenated side, depending on the size and on the prefix of the surface energy term of the hydrogenated and dehydrogenated material. Additional complexity appears when solid-state reactions of complex hydrides are considered and phase segregation has to be taken into account. In such a case the reversibility of complex hydrides may be reduced if the nanoparticles are free standing on a surface. However, it may be enhanced if the system is enclosed by a nanoscale void which prevents the reaction partners on the dehydrogenated side from diffusing away from each other. Moreover, the generally enhanced diffusivity in nanocrystalline systems may lower the kinetic barriers for the material's transformation and, thus, facilitate hydrogen absorption and desorption.

  17. Electronic Principles of Hydrogen Incorporation and Dynamics in Metal Hydrides

    Directory of Open Access Journals (Sweden)

    Ljiljana Matović

    2012-08-01

    Full Text Available An approach to various metal hydrides based on electronic principles is presented. The effective medium theory (EMT is used to illustrate fundamental aspects of metal-hydrogen interaction and clarify the most important processes taking place during the interaction. The elaboration is extended using the numerous existing results of experiment and calculations, as well as using some new material. In particular, the absorption/desorption of H in the Mg/MgH2 system is analyzed in detail, and all relevant initial structures and processes explained. Reasons for the high stability and slow sorption in this system are noted, and possible solutions proposed. The role of the transition-metal impurities in MgH2 is briefly discussed, and some interesting phenomena, observed in complex intermetallic compounds, are mentioned. The principle mechanism governing the Li-amide/imide transformation is also discussed. Latterly, some perspectives for the metal-hydrides investigation from the electronic point of view are elucidated.

  18. A free-piston Stirling cryocooler using metal diaphragms

    Science.gov (United States)

    Caughley, Alan; Sellier, Mathieu; Gschwendtner, Michael; Tucker, Alan

    2016-12-01

    A novel concept for a free-piston Stirling cryocooler has been proposed. The concept uses a pair of metal diaphragms to seal and suspend the displacer of a free-piston Stirling cryocooler. The diaphragms allow the displacer to move without rubbing or moving seals, potentially resulting in a long-life mechanism. When coupled to a metal diaphragm pressure wave generator, the system produces a complete Stirling cryocooler with no rubbing parts in the working gas space. Initial modelling of this concept using the Sage modelling tool indicates the potential for a useful cryocooler. A proof-of-concept prototype was constructed and achieved cryogenic temperatures. A second prototype was designed and constructed using the experience gained from the first. The prototype produced 29 W of cooling at 77 K and reached a no-load temperature of 56 K. Sage predicted the macroscopic behaviour of the prototype well but did not provide sufficient insights to improve performance significantly. This paper presents details of the development, modelling and testing of the proof-of-concept prototype and a second, improved prototype.

  19. Cryogenic cooling with cryocooler on a rotating system

    CERN Document Server

    Oguri, Shugo; Kawai, Masanori; Tajima, Osamu

    2013-01-01

    We developed a system that continuously maintains a cryocooler for long periods on a rotating table. A cryostat that holds the cryocooler is set on the table. A compressor is located on the ground and supplies high-purity (> 99.999%) and high-pressure (1.7 MPa) helium gas and electricity to the cryocooler. The operation of the cryocooler and other instruments requires the development of interface components between the ground and rotating table. A combination of access holes at the center of the table and two rotary joints allows simultaneous circulation of electricity and helium gas. The developed system provides two innovative functions under the rotating condition; cooling from room temperature and the maintenance of a cold condition for long periods. We have confirmed these abilities as well as temperature stability under a condition of continuous rotation at 20 revolutions per minute. The developed system can be applied in various fields; e.g., in tests of Lorentz invariance, searches for axion, radio as...

  20. Operating single quantum emitters with a compact Stirling cryocooler

    Energy Technology Data Exchange (ETDEWEB)

    Schlehahn, A.; Krüger, L.; Gschrey, M.; Schulze, J.-H.; Rodt, S.; Strittmatter, A.; Heindel, T., E-mail: tobias.heindel@tu-berlin.de; Reitzenstein, S. [Institute of Solid State Physics, Technische Universität Berlin, 10623 Berlin (Germany)

    2015-01-15

    The development of an easy-to-operate light source emitting single photons has become a major driving force in the emerging field of quantum information technology. Here, we report on the application of a compact and user-friendly Stirling cryocooler in the field of nanophotonics. The Stirling cryocooler is used to operate a single quantum emitter constituted of a semiconductor quantum dot (QD) at a base temperature below 30 K. Proper vibration decoupling of the cryocooler and its surrounding enables free-space micro-photoluminescence spectroscopy to identify and analyze different charge-carrier states within a single quantum dot. As an exemplary application in quantum optics, we perform a Hanbury-Brown and Twiss experiment demonstrating a strong suppression of multi-photon emission events with g{sup (2)}(0) < 0.04 from this Stirling-cooled single quantum emitter under continuous wave excitation. Comparative experiments performed on the same quantum dot in a liquid helium (LHe)-flow cryostat show almost identical values of g{sup (2)}(0) for both configurations at a given temperature. The results of this proof of principle experiment demonstrate that low-vibration Stirling cryocoolers that have so far been considered exotic to the field of nanophotonics are an attractive alternative to expensive closed-cycle cryostats or LHe-flow cryostats, which could pave the way for the development of high-quality table-top non-classical light sources.

  1. Cryogenic cooling with cryocooler on a rotating system.

    Science.gov (United States)

    Oguri, S; Choi, J; Kawai, M; Tajima, O

    2013-05-01

    We developed a system that continuously maintains a cryocooler for long periods on a rotating table. A cryostat that holds the cryocooler is set on the table. A compressor is located on the ground and supplies high-purity (>99.999%) and high-pressure (1.7 MPa) helium gas and electricity to the cryocooler. The operation of the cryocooler and other instruments requires the development of interface components between the ground and rotating table. A combination of access holes at the center of the table and two rotary joints allows simultaneous circulation of electricity and helium gas. The developed system provides two innovative functions under the rotating condition, cooling from room temperature and the maintenance of a cold condition for long periods. We have confirmed these abilities as well as temperature stability under a condition of continuous rotation at 20 rpm. The developed system can be applied in various fields, e.g., in tests of Lorentz invariance, searches for axion, radio astronomy, and cosmology, and application of radar systems. In particular, there is a plan to use this system for a radio telescope observing cosmic microwave background radiation.

  2. Cryogenic cooling with cryocooler on a rotating system

    Science.gov (United States)

    Oguri, S.; Choi, J.; Kawai, M.; Tajima, O.

    2013-05-01

    We developed a system that continuously maintains a cryocooler for long periods on a rotating table. A cryostat that holds the cryocooler is set on the table. A compressor is located on the ground and supplies high-purity (>99.999%) and high-pressure (1.7 MPa) helium gas and electricity to the cryocooler. The operation of the cryocooler and other instruments requires the development of interface components between the ground and rotating table. A combination of access holes at the center of the table and two rotary joints allows simultaneous circulation of electricity and helium gas. The developed system provides two innovative functions under the rotating condition, cooling from room temperature and the maintenance of a cold condition for long periods. We have confirmed these abilities as well as temperature stability under a condition of continuous rotation at 20 rpm. The developed system can be applied in various fields, e.g., in tests of Lorentz invariance, searches for axion, radio astronomy, and cosmology, and application of radar systems. In particular, there is a plan to use this system for a radio telescope observing cosmic microwave background radiation.

  3. Operating single quantum emitters with a compact Stirling cryocooler.

    Science.gov (United States)

    Schlehahn, A; Krüger, L; Gschrey, M; Schulze, J-H; Rodt, S; Strittmatter, A; Heindel, T; Reitzenstein, S

    2015-01-01

    The development of an easy-to-operate light source emitting single photons has become a major driving force in the emerging field of quantum information technology. Here, we report on the application of a compact and user-friendly Stirling cryocooler in the field of nanophotonics. The Stirling cryocooler is used to operate a single quantum emitter constituted of a semiconductor quantum dot (QD) at a base temperature below 30 K. Proper vibration decoupling of the cryocooler and its surrounding enables free-space micro-photoluminescence spectroscopy to identify and analyze different charge-carrier states within a single quantum dot. As an exemplary application in quantum optics, we perform a Hanbury-Brown and Twiss experiment demonstrating a strong suppression of multi-photon emission events with g((2))(0) Stirling-cooled single quantum emitter under continuous wave excitation. Comparative experiments performed on the same quantum dot in a liquid helium (LHe)-flow cryostat show almost identical values of g((2))(0) for both configurations at a given temperature. The results of this proof of principle experiment demonstrate that low-vibration Stirling cryocoolers that have so far been considered exotic to the field of nanophotonics are an attractive alternative to expensive closed-cycle cryostats or LHe-flow cryostats, which could pave the way for the development of high-quality table-top non-classical light sources.

  4. Operating single quantum emitters with a compact Stirling cryocooler

    Science.gov (United States)

    Schlehahn, A.; Krüger, L.; Gschrey, M.; Schulze, J.-H.; Rodt, S.; Strittmatter, A.; Heindel, T.; Reitzenstein, S.

    2015-01-01

    The development of an easy-to-operate light source emitting single photons has become a major driving force in the emerging field of quantum information technology. Here, we report on the application of a compact and user-friendly Stirling cryocooler in the field of nanophotonics. The Stirling cryocooler is used to operate a single quantum emitter constituted of a semiconductor quantum dot (QD) at a base temperature below 30 K. Proper vibration decoupling of the cryocooler and its surrounding enables free-space micro-photoluminescence spectroscopy to identify and analyze different charge-carrier states within a single quantum dot. As an exemplary application in quantum optics, we perform a Hanbury-Brown and Twiss experiment demonstrating a strong suppression of multi-photon emission events with g(2)(0) < 0.04 from this Stirling-cooled single quantum emitter under continuous wave excitation. Comparative experiments performed on the same quantum dot in a liquid helium (LHe)-flow cryostat show almost identical values of g(2)(0) for both configurations at a given temperature. The results of this proof of principle experiment demonstrate that low-vibration Stirling cryocoolers that have so far been considered exotic to the field of nanophotonics are an attractive alternative to expensive closed-cycle cryostats or LHe-flow cryostats, which could pave the way for the development of high-quality table-top non-classical light sources.

  5. Determination of arsenic and selenium by hydride generation and headspace solid phase microextraction coupled with optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tyburska, Anna; Jankowski, Krzysztof, E-mail: kj@ch.pw.edu.pl; Rodzik, Agnieszka

    2011-07-15

    A hydride generation headspace solid phase microextraction technique has been developed in combination with optical emission spectrometry for determination of total arsenic and selenium. Hydrides were generated in a 10 mL volume septum-sealed vial and subsequently collected onto a polydimethylsiloxane/Carboxen solid phase microextraction fiber from the headspace of sample solution. After completion of the sorption, the fiber was transferred into a thermal desorption unit and the analytes were vaporized and directly introduced into argon inductively coupled plasma or helium microwave induced plasma radiation source. Experimental conditions of hydride formation reaction as well as sorption and desorption of analytes have been optimized showing the significant effect of the type of the solid phase microextraction fiber coating, the sorption time and hydrochloric acid concentration of the sample solution on analytical characteristics of the method developed. The limits of detection of arsenic and selenium were 0.1 and 0.8 ng mL{sup -1}, respectively. The limit of detection of selenium could be improved further using biosorption with baker's yeast Saccharomyces cerevisiae for analyte preconcentration. The technique was applied for the determination of total As and Se in real samples.

  6. Thermodynamic analysis and experimental verfication on a novel looped pulse tube cryocooler

    Science.gov (United States)

    Wang, Xiaotao; Luo, Ercang; Dai, Wei; Hu, Jianying; Zhou, Yuan

    2012-06-01

    Compared with the Stirling cryocooler, the pulse tube cryocooler has obvious advantage in reliability. The reservoir is usually needed to help the inertance tube to obtain larger phase shifting ability, which makes the pulse tube cryocooler not to be as compact as the Stirling cryocoolers. To improve compactness, a looped pulse tube cryocooler without the reservoir was proposed in the paper. The inertance-tube is directly connected to the backside of a linear compressor and the reservoir is removed. To compare its cooling performance with that of the inertance-tube pulse tube cryocooler with a reservoir, the theoretical model including a linear compressor, main hot-end exchanger, regenerator, cold-end exchanger, pulse tube, and secondary hot-end exchanger are described for the both cryocoolers. The simulation results show that the looped cryocooler can achieve a similar or even better cooling performance, comparing with the traditional inertance-tube cryocooler. In the experiment, the performances of both cryocoolers driven by a same linear compressor were extensively tested. A lowest cold-head temperature of 40 K is acquired and the maximum cooling power reached 9.4 W at 77 K for the novel looped pulse tube cooler, corresponding to about 15% relative Carnot efficiency

  7. Elevated-pressure mixed-coolants Joule Thomson cryocooling

    Science.gov (United States)

    Maytal, B.-Z.; Nellis, G. F.; Klein, S. A.; Pfotenhauer, J. M.

    2006-01-01

    This paper explores the potential of mixed coolants at elevated pressures for Joule-Thomson cryocooling. A numerical model of a Joule-Thomson cryocooler is developed that is capable of simulating operation with mixtures of up to 9 components consisting of hydrocarbons, non-flammable halogenated refrigerants, and inert gases. The numerical model is integrated with a genetic optimization algorithm, which has a high capability for convergence in an environment of discontinuities, constraints and local optima. The genetic optimization algorithm is used to select the optimal mixture compositions that separately maximizes following two objective functions at each elevated pressure for 80, 90 and 95 K cryocooling: the molar specific cooling capacity (the highest attainable is 3200 J/mol) and the produced cooling capacity per thermal conductance which is a measure of the compactness of the recuperator. The optimized cooling capacity for a non-flammable halogenated refrigerant mixture is smaller than for a hydrocarbon mixture; however, the cooling capacity of the two types of mixtures approach one another as pressure becomes higher. The coefficient of performance, the required heat transfer area and the effect of the number of components in the mixture is investigated as a function of the pressure. It is shown that mixtures with more components provide a higher cooling capacity but require larger recuperative heat exchangers. Optimized mixtures for 90 K cryocooling have similar cooling capacity as those for 80 K. Optimized compactness for 80 K is about 50% higher than can be achieved by pure nitrogen. For 90 K, no mixture provides a more compact recuperator than can be achieved using pure argon. The results are discussed in the context of potential applications for closed and open cycle cryocoolers.

  8. Theory on single molecule_photon cryocooler

    Institute of Scientific and Technical Information of China (English)

    QIN; Weiping

    2001-01-01

    [1]Pringsheim, P., Zwei Bemerkungen über den Unterschied von Lumineszenz_ und Temperaturstrahlung, Z. Phys., 929, 57(8): 739.[2]Djeu, N., Whitney, W. T., Laser cooling by spontaneous anti_Stokes scattering, Phys. Rev. Lett., 98, 46(4): 236.[3]Epstein, I., Buchwald, M. I., Edwards, B. C. et al., Observation of laser_induced fluorescent cooling of a solid, Nature, 995, 377(2): 500.[4]Clark, J. L., Rumbles, G., Laser cooling in the condensed phase by frequency up_conversion, Phys. Rev. Lett., 996, 76(2): 2037.[5]Mungan, C. E., Buchwald, M. I., Edwards, B. C. et al., Laser cooling of a solid by 6 K starting from room temperature, Phys. Rev. Lett., 997, 78(6): 030.[6]Luo, X., Eisaman, M. D., Gosnell, T. R., Laser cooling of a solid by 2K starting from room temperature, Opt. Lett., 998, 23(8): 639.[7]Gosnell, T. R., Laser cooling of a solid by 2K starting from room temperature, Optics Let., 999, 24(5): 04.[8]Epstein, I., Buchwald, M. I., Edwards, B. C. et al., The Los Alamos solid_state optical refrigerator, Cryocoolers 9, New York: Plenum, 997, 68—686.[9]Qin Weiping, Zhang Jiahua, Huang Shihua, Laser_induced anti_Stokes fluorescent cooling, Physics (in Chinese), 998, 27(6): 323.[10]Christiansen, W. H., Hertzberg, A., Gasdynamic lasers and photon machines, Proc. IEEE, 973, 6(8): 060.[11]Qin Weiping, Zhang Jiahua, Huang Shihua, Study on the fluorescent cooling by energy transfer within in homogenous line shape in solids, Acta Physica Sinica (in Chinese), 998, 47(8): 397.[12]Qin Weiping, Zhang Jiahua, Chen Baojiu et al., Two basic mechanism in anti_Stokes fluorescent cooling of solids, Chinese Journal of Luminescence, 999, 20(2): 26.[13]Fournier, J. T., Bartram, R. H., Inhomogeneous broadening of the optical spectra of Yb3+in phosphate glass, J. Phys. Chem. Solids, 970, 3(2): 265.

  9. Development of a modular room-temperature hydride storage system for vehicular applications

    Science.gov (United States)

    Capurso, Giovanni; Schiavo, Benedetto; Jepsen, Julian; Lozano, Gustavo; Metz, Oliver; Saccone, Adriana; De Negri, Serena; Bellosta von Colbe, José M.; Klassen, Thomas; Dornheim, Martin

    2016-03-01

    The subject of this paper concerns the development of a vehicular hydrogen tank system, using a commercial interstitial metal hydride as storage material. The design of the tank was intended to feed a fuel cell in a light prototype vehicle, and the chosen hydride material, Hydralloy C5 by GfE, was expected to be able to absorb and desorb hydrogen in a range of pressure suitable for this purpose. A systematic analysis of the material in laboratory scale allows an extrapolation of the thermodynamic and reaction kinetics data. The following development of the modular tank was done according to the requirements of the prototype vehicle propulsion system and led to promising intermediate results. The modular approach granted flexibility in the design, allowing both to reach carefully the design goals and to learn the limiting factors in the sorption process. Proper heat management and suitable equipment remain key factors in order to achieve the best performances.

  10. The renaissance of hydrides as energy materials

    Science.gov (United States)

    Mohtadi, Rana; Orimo, Shin-Ichi

    2017-02-01

    Materials based on hydrides have been the linchpin in the development of several practical energy storage technologies, of which the most prominent example is nickel-metal hydride batteries. Motivated by the need to meet the future's energy demand, the past decade has witnessed substantial advancements in the research and development of hydrides as media for hydrogen energy storage. More recently, new and rapidly evolving discoveries have positioned hydrides as highly promising materials for future electrochemical energy storage, such as electrolytes for mono- and divalent batteries, and anodes for lithium-ion batteries. In addition, the potential of hydrides in efficient power transmission has been recently revealed. In this Review, we highlight key advances and illustrate how the versatility of hydrides has not only yielded a meaningful past, but also ensures a very bright future.

  11. Rechargeable metal hydrides for spacecraft application

    Science.gov (United States)

    Perry, J. L.

    1988-01-01

    Storing hydrogen on board the Space Station presents both safety and logistics problems. Conventional storage using pressurized bottles requires large masses, pressures, and volumes to handle the hydrogen to be used in experiments in the U.S. Laboratory Module and residual hydrogen generated by the ECLSS. Rechargeable metal hydrides may be competitive with conventional storage techniques. The basic theory of hydride behavior is presented and the engineering properties of LaNi5 are discussed to gain a clear understanding of the potential of metal hydrides for handling spacecraft hydrogen resources. Applications to Space Station and the safety of metal hydrides are presented and compared to conventional hydride storage. This comparison indicates that metal hydrides may be safer and require lower pressures, less volume, and less mass to store an equivalent mass of hydrogen.

  12. Siderophore sorption to clays.

    Science.gov (United States)

    Maurice, Patricia A; Haack, Elizabeth A; Mishra, Bhoopesh

    2009-08-01

    Siderophores are low molecular weight organic ligands exuded by some aerobic organisms and plants to acquire Fe under Fe-limited conditions. The hydroxamate siderophores may sorb to aluminosilicate clays through a variety of mechanisms depending upon the nature of the clay and of the siderophore along with solution conditions such as pH, ionic strength, and presence of metal cations. They may also affect metal binding to clays. Here, we review previous studies of siderophore sorption to aluminosilicate clays; briefly discuss how the techniques of X-ray diffractometry, Fourier-transform infrared spectroscopy, and X-ray absorption spectroscopy may be applied to such studies; review effects of siderophores on metal sorption to clays; and highlight some areas for future research.

  13. TECHNETIUM SORPTION MEDIA REVIEW

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB; KELLY SE; ROBBINS RA; ADAMS RD; THORSON MA; HAASS CC

    2011-08-25

    This report presents information and references to aid in the selection of 99Tc sorption media for feasibility studies regarding the removal of 99Tc from Hanford's low activity waste. The report contains literature search material for sorption media (including ion exchange media) for the most tested media to date, including SuperLig 639, Reillex HPQ, TAM (Kruion), Purolite A520E and A530E, and Dowex 1X8. The U.S. Department of Energy (DOE), Office of River Protection (ORP) is responsible for management and completion of the River Protection Project (RPP) mission, which comprises both the Hanford Site tank farms and the Waste Treatment and Immobilization Plant (WTP). The RPP mission is to store, retrieve and treat Hanford's tank waste; store and dispose of treated wastes; and close the tank farm waste management areas and treatment facilities in a safe, environmentally compliant, cost-effective and energy-effective manner.

  14. Nanostructured, complex hydride systems for hydrogen generation

    Directory of Open Access Journals (Sweden)

    Robert A. Varin

    2015-02-01

    Full Text Available Complex hydride systems for hydrogen (H2 generation for supplying fuel cells are being reviewed. In the first group, the hydride systems that are capable of generating H2 through a mechanical dehydrogenation phenomenon at the ambient temperature are discussed. There are few quite diverse systems in this group such as lithium alanate (LiAlH4 with the following additives: nanoiron (n-Fe, lithium amide (LiNH2 (a hydride/hydride system and manganese chloride MnCl2 (a hydride/halide system. Another hydride/hydride system consists of lithium amide (LiNH2 and magnesium hydride (MgH2, and finally, there is a LiBH4-FeCl2 (hydride/halide system. These hydride systems are capable of releasing from ~4 to 7 wt.% H2 at the ambient temperature during a reasonably short duration of ball milling. The second group encompasses systems that generate H2 at slightly elevated temperature (up to 100 °C. In this group lithium alanate (LiAlH4 ball milled with the nano-Fe and nano-TiN/TiC/ZrC additives is a prominent system that can relatively quickly generate up to 7 wt.% H2 at 100 °C. The other hydride is manganese borohydride (Mn(BH42 obtained by mechano-chemical activation synthesis (MCAS. In a ball milled (2LiBH4 + MnCl2 nanocomposite, Mn(BH42 co-existing with LiCl can desorb ~4.5 wt.% H2 at 100 °C within a reasonable duration of dehydrogenation. Practical application aspects of hydride systems for H2 generation/storage are also briefly discussed.

  15. Use of reversible hydrides for hydrogen storage

    Science.gov (United States)

    Darriet, B.; Pezat, M.; Hagenmuller, P.

    1980-01-01

    The addition of metals or alloys whose hydrides have a high dissociation pressure allows a considerable increase in the hydrogenation rate of magnesium. The influence of temperature and hydrogen pressure on the reaction rate were studied. Results concerning the hydriding of magnesium rich alloys such as Mg2Ca, La2Mg17 and CeMg12 are presented. The hydriding mechanism of La2Mg17 and CeMg12 alloys is given.

  16. Inhibited solid propellant composition containing beryllium hydride

    Science.gov (United States)

    Thompson, W. W. (Inventor)

    1978-01-01

    An object of this invention is to provide a composition of beryllium hydride and carboxy-terminated polybutadiene which is stable. Another object of this invention is to provide a method for inhibiting the reactivity of beryllium hydride toward carboxy-terminated polybutadiene. It was found that a small amount of lecithin inhibits the reaction of beryllium hydride with the acid groups in carboxy terminated polybutadiene.

  17. Development and optimization progress with RICOR cryocoolers for HOT IR detectors

    Science.gov (United States)

    Katz, Amiram; Bar Haim, Zvi; Riabzev, Sergey; Segal, Victor; Filis, Avishai; Gover, Dan

    2016-05-01

    The world growth in research and development of High Operating Temperature (HOT) IR detectors impels the development and optimization of suitable cryocoolers. The current developments at RICOR, which include three different cryocooler models and two new controllers, are focused on the - oriented design process, meaning small Size, low Weight, low Power consumption, improved performance and lower production cost, providing proper cryocoolers for future hand held thermal imagers. This paper shows the progress made during development of "HOT" cryocooler prototypes, engineering pre-production series and qualified production series cryocoolers working at the FPA temperature range of 130 - 200K. The progress with development of electronic control modules providing minimized regulated power consumption is also shown. The progress in development of cryocoolers reliability is also reported in the paper.

  18. Anodematerials for Metal Hydride Batteries

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf

    1997-01-01

    by annealing at 700°C for 12 hours. The alloys appeared to be nanocrystalline with an average crystallite size around 10 nm before annealing. Special steel containers was developed for the annealing of the metal powders in inert atmosphere. The use of various annealing temperatures was investigated......This report describes the work on development of hydride forming alloys for use as electrode materials in metal hydride batteries. The work has primarily been concentrated on calcium based alloys derived from the compound CaNi5. This compound has a higher capacity compared with alloys used in today...... was developed. The parameters milling time, milling intensity, number of balls and form of the alloying metals were investigated. Based on this a final alloying technique for the subsequent preparation of electrode materials was established. The technique comprises milling for 4 hours twice possibly followed...

  19. Predicting formation enthalpies of metal hydrides

    DEFF Research Database (Denmark)

    Andreasen, A.

    2004-01-01

    In order for the hydrogen based society viz. a society in which hydrogen is the primary energy carrier to become realizable an efficient way of storing hydrogen is required. For this purpose metal hydrides are serious candidates. Metal hydrides are formedby chemical reaction between hydrogen...... and metal and for the stable hydrides this is associated with release of heat (#DELTA#H_f ). The more thermodynamically stable the hydride, the larger DHf, and the higher temperature is needed in order to desorphydrogen (reverse reaction) and vice versa. For practical application the temperature needed...

  20. Research on Metal Hydride Compressor System

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Ti-Zr series Laves phase hydrogen storage alloys with good hydrogen storage properties, such as large hydrogen capacity, rapid hydriding and dehydriding rate, high compression ratio, gentle plateau, small hysteresis, easily being activated and long cyclic stability etc. for metal hydride compressor have been investigated. In addition, a hydride compressor with special characteristics, namely, advanced filling method, good heat transfer effect and reasonable structural design etc. has also been constructed. A hydride compressor cryogenic system has been assembled coupling the compressor with a J-T micro-throttling refrigeration device and its cooling capacity can reach 0.4 W at 25 K.

  1. Thermodynamic Hydricity of Transition Metal Hydrides.

    Science.gov (United States)

    Wiedner, Eric S; Chambers, Matthew B; Pitman, Catherine L; Bullock, R Morris; Miller, Alexander J M; Appel, Aaron M

    2016-08-10

    Transition metal hydrides play a critical role in stoichiometric and catalytic transformations. Knowledge of free energies for cleaving metal hydride bonds enables the prediction of chemical reactivity, such as for the bond-forming and bond-breaking events that occur in a catalytic reaction. Thermodynamic hydricity is the free energy required to cleave an M-H bond to generate a hydride ion (H(-)). Three primary methods have been developed for hydricity determination: the hydride transfer method establishes hydride transfer equilibrium with a hydride donor/acceptor pair of known hydricity, the H2 heterolysis method involves measuring the equilibrium of heterolytic cleavage of H2 in the presence of a base, and the potential-pKa method considers stepwise transfer of a proton and two electrons to give a net hydride transfer. Using these methods, over 100 thermodynamic hydricity values for transition metal hydrides have been determined in acetonitrile or water. In acetonitrile, the hydricity of metal hydrides spans a range of more than 50 kcal/mol. Methods for using hydricity values to predict chemical reactivity are also discussed, including organic transformations, the reduction of CO2, and the production and oxidation of hydrogen.

  2. Coinage Metal Hydrides: Synthesis, Characterization, and Reactivity.

    Science.gov (United States)

    Jordan, Abraham J; Lalic, Gojko; Sadighi, Joseph P

    2016-08-10

    Hydride complexes of copper, silver, and gold encompass a broad array of structures, and their distinctive reactivity has enabled dramatic recent advances in synthesis and catalysis. This Review summarizes the synthesis, characterization, and key stoichiometric reactions of isolable or observable coinage metal hydrides. It discusses catalytic processes in which coinage metal hydrides are known or probable intermediates, and presents mechanistic studies of selected catalytic reactions. The purpose of this Review is to convey how developments in coinage metal hydride chemistry have led to new organic transformations, and how developments in catalysis have in turn inspired the synthesis of reactive new complexes.

  3. Crystal structure of gold hydride

    Energy Technology Data Exchange (ETDEWEB)

    Degtyareva, Valentina F., E-mail: degtyar@issp.ac.ru

    2015-10-05

    Highlights: • Volume expansion of metal hydrides is due to the increase in the s-band filling. • AuH structure is similar to that of Hg having one more s electron compared to Au. • Structure stability of both Hg and AuH is governed by the Hume-Rothery rule. - Abstract: A number of transition metal hydrides with close-packed metal sublattices of fcc or hcp structures with hydrogen in octahedral interstitial positions were obtained by the high-pressure-hydrogen technique described by Ponyatovskii et al. (1982). In this paper we consider volume increase of metals by hydrogenation and possible crystal structure of gold hydride in relation with the structure of mercury, the nearest neighbor of Au in the Periodic table. Suggested structure of AuH has a basic tetragonal body-centered cell that is very similar to the mercury structure Hg-t I 2. The reasons of stability for this structure are discussed within the model of Fermi sphere–Brillouin zone interactions.

  4. Sorption of actinides onto nanodiamonds

    Energy Technology Data Exchange (ETDEWEB)

    Buchatskaya, Yulia; Romanchuk, Anna; Yakovlev, Ruslan; Kulakova, Inna [Lomonosov Moscow State Univ., Moscow (Russian Federation). Dept. of Chemistry; Shiryaev, Andrei [Russian Academy of Sciences, Moscow (Russian Federation). Frumkin Institute of Physical Chemistry and Electrochemistry; Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry; Kalmykov, Stepan [Lomonosov Moscow State Univ., Moscow (Russian Federation). Dept. of Chemistry; Russian Academy of Sciences, Moscow (Russian Federation). Frumkin Institute of Physical Chemistry and Electrochemistry; Russian Academy of Sciences, Moscow (Russian Federation). Vernadsky Institute of Geochemistry and Analytical Chemistry

    2015-06-01

    Detonation nanodiamonds (ND) present a significant part of nanocarbons group, which could be produced on commercial scale by detonation of explosives in a closed chamber. Their unique properties of high surface area, low weight and radiation resistance make ND a prospective candidate for applications in sorption processes in radiochemistry. To study the influence of surface chemistry on sorption properties, apristine sample of ND was treated with acids and hydrogen. The surface chemistry of the samples was characterised by infrared spectroscopy, X-ray photoelectron spectroscopy and Boehm titration. The sorption properties of ND were tested fordifferent radionuclides. The sorption capacity of ND was shown to be higher than those of commonly used radionuclide sorbents like activated carbon and compariable to other members of nanocarbon group like graphene oxide and carbon nanotubes. The sorption properties were shown to be influenced by the presence of oxygen-containing groups on the surface of ND. This represents an opportunity to increase the sorption capacity of ND.

  5. Metal hydrides as electrode/catalyst materials for oxygen evolution/reduction in electrochemical devices

    Science.gov (United States)

    Bugga, Ratnakumar V. (Inventor); Halpert, Gerald (Inventor); Fultz, Brent (Inventor); Witham, Charles K. (Inventor); Bowman, Robert C. (Inventor); Hightower, Adrian (Inventor)

    1997-01-01

    An at least ternary metal alloy of the formula, AB.sub.(5-Y)X(.sub.y), is claimed. In this formula, A is selected from the rare earth elements, B is selected from the elements of groups 8, 9, and 10 of the periodic table of the elements, and X includes at least one of the following: antimony, arsenic, and bismuth. Ternary or higher-order substitutions, to the base AB.sub.5 alloys, that form strong kinetic interactions with the predominant metals in the base metal hydride are used to form metal alloys with high structural integrity after multiple cycles of hydrogen sorption.

  6. Fundamental experiments on hydride reorientation in zircaloy

    Science.gov (United States)

    Colas, Kimberly B.

    In the current study, an in-situ X-ray diffraction technique using synchrotron radiation was used to follow directly the kinetics of hydride dissolution and precipitation during thermomechanical cycles. This technique was combined with conventional microscopy (optical, SEM and TEM) to gain an overall understanding of the process of hydride reorientation. Thus this part of the study emphasized the time-dependent nature of the process, studying large volume of hydrides in the material. In addition, a micro-diffraction technique was also used to study the spatial distribution of hydrides near stress concentrations. This part of the study emphasized the spatial variation of hydride characteristics such as strain and morphology. Hydrided samples in the shape of tensile dog-bones were used in the time-dependent part of the study. Compact tension specimens were used during the spatial dependence part of the study. The hydride elastic strains from peak shift and size and strain broadening were studied as a function of time for precipitating hydrides. The hydrides precipitate in a very compressed state of stress, as measured by the shift in lattice spacing. As precipitation proceeds the average shift decreases, indicating average stress is reduced, likely due to plastic deformation and morphology changes. When nucleation ends the hydrides follow the zirconium matrix thermal contraction. When stress is applied below the threshold stress for reorientation, hydrides first nucleate in a very compressed state similar to that of unstressed hydrides. After reducing the average strain similarly to unstressed hydrides, the average hydride strain reaches a constant value during cool-down to room temperature. This could be due to a greater ease of deforming the matrix due to the applied far-field strain which would compensate for the strains due to thermal contraction. Finally when hydrides reorient, the average hydride strains become tensile during the first precipitation regime and

  7. Development of miniature Stirling cryocooler technology for Infrared Focal Plane array

    National Research Council Canada - National Science Library

    Manmohan Singh; Mukesh Sadana; Sunil Sachdev; Gaurav Pratap

    2013-01-01

    .... The paper presents the progress of the development activities in Stirling cryocooler technology at SSPL, which evolved through essential milestones like the development of single and dual piston...

  8. Metal Hydrides for Rechargeable Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Valoeen, Lars Ole

    2000-03-01

    Rechargeable battery systems are paramount in the power supply of modern electronic and electromechanical equipment. For the time being, the most promising secondary battery systems for the future are the lithium-ion and the nickel metal hydride (NiMH) batteries. In this thesis, metal hydrides and their properties are described with the aim of characterizing and improving those. The thesis has a special focus on the AB{sub 5} type hydrogen storage alloys, where A is a rare earth metal like lanthanum, or more commonly misch metal, which is a mixture of rare earth metals, mainly lanthanum, cerium, neodymium and praseodymium. B is a transition metal, mainly nickel, commonly with additions of aluminium, cobalt, and manganese. The misch metal composition was found to be very important for the geometry of the unit cell in AB{sub 5} type alloys, and consequently the equilibrium pressure of hydrogen in these types of alloys. The A site substitution of lanthanum by misch metal did not decrease the surface catalytic properties of AB{sub 5} type alloys. B-site substitution of nickel with other transition elements, however, substantially reduced the catalytic activity of the alloy. If the internal pressure within the electrochemical test cell was increased using inert argon gas, a considerable increase in the high rate charge/discharge performance of LaNi{sub 5} was observed. An increased internal pressure would enable the utilisation of alloys with a high hydrogen equivalent pressure in batteries. Such alloys often have favourable kinetics and high hydrogen diffusion rates and thus have a potential for improving the high current discharge rates in metal hydride batteries. The kinetic properties of metal hydride electrodes were found to improve throughout their lifetime. The activation properties were found highly dependent on the charge/discharge current. Fewer charge/discharge cycles were needed to activate the electrodes if a small current was used instead of a higher

  9. Metal Hydrides for Rechargeable Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Valoeen, Lars Ole

    2000-03-01

    Rechargeable battery systems are paramount in the power supply of modern electronic and electromechanical equipment. For the time being, the most promising secondary battery systems for the future are the lithium-ion and the nickel metal hydride (NiMH) batteries. In this thesis, metal hydrides and their properties are described with the aim of characterizing and improving those. The thesis has a special focus on the AB{sub 5} type hydrogen storage alloys, where A is a rare earth metal like lanthanum, or more commonly misch metal, which is a mixture of rare earth metals, mainly lanthanum, cerium, neodymium and praseodymium. B is a transition metal, mainly nickel, commonly with additions of aluminium, cobalt, and manganese. The misch metal composition was found to be very important for the geometry of the unit cell in AB{sub 5} type alloys, and consequently the equilibrium pressure of hydrogen in these types of alloys. The A site substitution of lanthanum by misch metal did not decrease the surface catalytic properties of AB{sub 5} type alloys. B-site substitution of nickel with other transition elements, however, substantially reduced the catalytic activity of the alloy. If the internal pressure within the electrochemical test cell was increased using inert argon gas, a considerable increase in the high rate charge/discharge performance of LaNi{sub 5} was observed. An increased internal pressure would enable the utilisation of alloys with a high hydrogen equivalent pressure in batteries. Such alloys often have favourable kinetics and high hydrogen diffusion rates and thus have a potential for improving the high current discharge rates in metal hydride batteries. The kinetic properties of metal hydride electrodes were found to improve throughout their lifetime. The activation properties were found highly dependent on the charge/discharge current. Fewer charge/discharge cycles were needed to activate the electrodes if a small current was used instead of a higher

  10. Development of high capacity Stirling type pulse tube cryocooler

    Energy Technology Data Exchange (ETDEWEB)

    Imura, J. [College of Science and Technology, Nihon University, 7-24-1, Narashinodai, Funabashi-shi, Chiba 274-8501 (Japan)], E-mail: junnosuke_imura@yahoo.co.jp; Shinoki, S.; Sato, T.; Iwata, N.; Yamamoto, H.; Yasohama, K. [College of Science and Technology, Nihon University, 7-24-1, Narashinodai, Funabashi-shi, Chiba 274-8501 (Japan); Ohashi, Y.; Nomachi, H.; Okumura, N. [Aisin Seiki Co., Ltd., 2-1, Asahi-machi, Kariya, Aichi 448-8650 (Japan); Nagaya, S.; Tamada, T.; Hirano, N. [Chubu Electric Power Co., Inc., 1, Toshin-cho, Higashi-ku, Nagoya-shi, Aichi 261-8680 (Japan)

    2007-10-01

    We have been developing a Stirling type pulse tube cryocooler, aiming for a cooling capacity of 200 W at 80 K for a superconducting magnetic energy storage system. In this work, we adopted stainless steel meshes for the regenerator of the cryocooler, and studied the influences of the mesh number on the cooling capacity. The prepared mesh numbers were 150, 200, 250, 350 and 400. Using 250 mesh, and at a frequency of 45 Hz and power consumption of 3.1 kW, the achievable lowest temperature and cooling capacity at 80 K was 46.2 K and 123 W, respectively. Furthermore, in order to optimize the performance, some regenerators were made by stacking several kinds of meshes with different stacking orders. Using these regenerators, we have obtained a high cooling capacity of 169 W at 80 K with power consumption of 4 kW.

  11. Development of high capacity Stirling type pulse tube cryocooler

    Science.gov (United States)

    Imura, J.; Shinoki, S.; Sato, T.; Iwata, N.; Yamamoto, H.; Yasohama, K.; Ohashi, Y.; Nomachi, H.; Okumura, N.; Nagaya, S.; Tamada, T.; Hirano, N.

    2007-10-01

    We have been developing a Stirling type pulse tube cryocooler, aiming for a cooling capacity of 200 W at 80 K for a superconducting magnetic energy storage system. In this work, we adopted stainless steel meshes for the regenerator of the cryocooler, and studied the influences of the mesh number on the cooling capacity. The prepared mesh numbers were #150, 200, 250, 350 and 400. Using #250 mesh, and at a frequency of 45 Hz and power consumption of 3.1 kW, the achievable lowest temperature and cooling capacity at 80 K was 46.2 K and 123 W, respectively. Furthermore, in order to optimize the performance, some regenerators were made by stacking several kinds of meshes with different stacking orders. Using these regenerators, we have obtained a high cooling capacity of 169 W at 80 K with power consumption of 4 kW.

  12. Development of SNSPD System with Gifford-McMahon Cryocooler

    CERN Document Server

    Miki, Shigehito; Sasaki, Masahide; Wang, Zhen

    2010-01-01

    A superconducting nanowire single photon detector (SNSPD) system for telecommunication wavelength using a GM cryocooler was developed and its performance was verified. The cryocooler based SNSPD system can operate continuously with a 100 V AC power supply without any cryogen. The packaged SNSPD device was cooled to 2.96 K within a thermal fluctuation range of 10 mK. An SNSPD with an area of 20 x 20 $\\mu m^2$ showed good system detection efficiency (DE) at 100 Hz dark count rate of 2.6% and 4.5% at wavelengths of 1550 and 1310 nm, respectively. An SNSPD with an area of 10 x 10 $\\mu m^2$ and kinetic inductance lower than that of the large area device showed good system DE of 2.6% at a wavelength of 1550 nm. The SNSPD system could be operated for over 10 h with constant system DE and dark count rate.

  13. A GM cryocooler with cold helium circulation for remote cooling

    Science.gov (United States)

    Wang, Chao; Brown, Ethan

    2014-01-01

    A GM cryocooler with new cold helium circulation system has been developed at Cryomech. A set of check valves connects to the cold heat exchanger to convert a small portion of AC oscillating flow in the cold head to a DC gas flow for circulating cold helium in the remote loop. A cold finger, which is used for remote cooling, is connected to the check valves through a pair of 5 m long vacuum insulated flexible lines. The GM cryocooler, Cryomech model AL125 having 120 W at 80 K, is employed in the testing. The cold finger can provide 50 W at 81 K for the power input of 4.1 kW and 70.5 W at 81.8 K for the power input of 6 kW. This simple and low cost design is very attractive for some applications in the near future.

  14. Helium liquefaction with a 4 K pulse tube cryocooler

    Science.gov (United States)

    Wang, Chao

    2001-07-01

    Helium liquefaction with a two-stage 4 K pulse tube cryocooler is introduced in this paper. The helium liquefier has a feature of precooling helium gas to be liquefied by using inefficiency of the second stage regenerator in the pulse tube cryocooler. This process reduces enthalpy of the incoming helium gas when entering the condenser and significantly increases the condensation rate. Numerical analysis predicts the precooling heat load on the second stage regenerator, decreases the PTC second stage cooling capacity by only 11% of the heat actually absorbed into the regenerator. A prototype pulse tube helium liquefier was built, which has two precooling heat exchangers on the first stage cold head and the second stage regenerator. It continuously liquefies helium with a rate of 4.8 l/day under normal pressure while consumes 4.6 kW power input.

  15. High pressure ratio cryocooler with integral expander and heat exchanger

    Science.gov (United States)

    Crunkleton, J. A.; Smith, J. L., Jr.; Iwasa, Y.

    A new 1 W, 4.2 K cryocooler is under development that is intended to miniaturize helium temperature refrigeration systems using a high-pressure-ratio Collins-type cycle. The configuration resulted from optimization studies of a saturated vapor compression (SCV) cycle that employs miniature parallel-plate heat exchangers. The basic configuration is a long displacer in a close-fitting, thin-walled cylinder. The displacer-to-cylinder gap is the high-pressure passage of the heat exchanger, and the low-pressure passage is formed by a thin tube over the OD of the cylinder. A solenoid-operated inlet valve admits 40 atm helium to the displacer-to-cylinder gap at room temperature, while the solenoid-operated exhaust valve operates at 4 atm. The single-stage cryocooler produces 1 W of refrigeration at 40 K without precooling and at 20 K with liquid nitrogen precooling.

  16. Performance Limits of Pulse Tube Cryocoolers Using 3HE

    Science.gov (United States)

    Kittel, P.

    2008-03-01

    The enthalpy, entropy, and exergy flows resulting from the real gas effects of 3He in ideal pulse tube cryocoolers are described. The discussion follows a previous description of the real gas effects of 4He in ideal pulse tube cryocoolers and makes use of a recently developed model of the thermophysical properties of 3He. This model is used to describe how the thermodynamic flows are affected by real gas phenomena of 3He and compares these effects to similar effects for 4He. The analysis was done over the pressure range 0.3-2 MPa and temperatures down to 1 K. At 2 MPa there is almost no difference in the cooling power between 3He and 4He. At lower pressures, using 3He is advantageous. There is a 1-2 K reduction in the 3He cooling power vs. temperature curves compared to those for 4He in the 0.3-1 MPa range.

  17. Kinetics of hydride front in Zircaloy-2 and H release from a fractional hydrided surface

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, M.; Gonzalez-Gonzalez, A.; Moya, J. S.; Remartinez, B.; Perez, S.; Sacedon, J. L. [Instituto de Ciencia de Materiales de Madrid (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain); Iberdrola, Tomas Redondo 3, 28033 Madrid (Spain); Instituto de Ciencia de Materiales de Madrid (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain)

    2009-07-15

    The authors study the hydriding process on commercial nuclear fuel claddings from their inner surface using an ultrahigh vacuum method. The method allows determining the incubation and failure times of the fuel claddings, as well as the dissipated energy and the partial pressure of the desorbed H{sub 2} from the outer surface of fuel claddings during the hydriding process. The correlation between the hydriding dissipated energy and the amount of zirconium hydride (formed at different stages of the hydriding process) leads to a near t{sup 1/2} potential law corresponding to the time scaling of the reaction for the majority of the tested samples. The calibrated relation between energy and hydride thickness allows one to calculate the enthalpy of the {delta}-ZrH{sub 1.5} phase. The measured H{sub 2} desorption from the external surface is in agreement with a proposed kinetic desorption model from the hydrides precipitated at the surface.

  18. Theoretical study on a Miniature Joule-Thomson & Bernoulli Cryocooler

    Science.gov (United States)

    Xiong, L. Y.; Kaiser, G.; Binneberg, A.

    2004-11-01

    In this paper, a microchannel-based cryocooler consisting of a compressor, a recuperator and a cold heat exchanger has been developed to study the feasibility of cryogenic cooling by the use of Joule-Thomson effect and Bernoulli effect. A set of governing equations including Bernoulli equations and energy equations are introduced and the performance of the cooler is calculated. The influences of some working conditions and structure parameters on the performance of coolers are discussed in details.

  19. Basic Operation of Cryocoolers and Related Thermal Machines

    Science.gov (United States)

    de Waele, A. T. A. M.

    2011-09-01

    This paper deals with the basics of cryocoolers and related thermodynamic systems. The treatment is based on the first and second law of thermodynamics for inhomogeneous, open systems using enthalpy flow, entropy flow, and entropy production. Various types of machines, which use an oscillating gas flow, are discussed such as: Stirling refrigerators, GM coolers, pulse-tube refrigerators, and thermoacoustic coolers and engines. Furthermore the paper deals with Joule-Thomson and dilution refrigerators which use a constant flow of the working medium.

  20. 10 K high frequency pulse tube cryocooler with precooling

    Science.gov (United States)

    Liu, Sixue; Chen, Liubiao; Wu, Xianlin; Zhou, Yuan; Wang, Junjie

    2016-07-01

    A high frequency pulse tube cryocooler with precooling (HPTCP) has been developed and tested to meet the requirement of weak magnetic signals measurement, and the performance characteristics are presented in this article. The HPTCP is a two-stage pulse tube cryocooler with the precooling-stage replaced by liquid nitrogen. Two regenerators completely filled with stainless steel (SS) meshes are used in the cooler. Together with cold inertance tubes and cold gas reservoir, a cold double-inlet configuration is used to control the phase relationship of the HPTCP. The experimental result shows that the cold double-inlet configuration has improved the performance of the cooler obviously. The effects of operation parameters on the performance of the cooler are also studied. With a precooling temperature of 78.5 K, the maximum refrigeration capacity is 0.26 W at 15 K and 0.92 W at 20 K when the input electric power are 174 W and 248 W respectively, and the minimum no-load temperature obtained is 10.3 K, which is a new record on refrigeration temperature for high frequency pulse tube cryocooler reported with SS completely used as regenerative matrix.

  1. Numerical analysis of stirling type pulse tube cryocoolers

    Science.gov (United States)

    Boroujerdi, A. A.; Ashrafizadeh, A.; Mousavi Naeenian, S. M.

    2011-09-01

    A one-dimensional finite volume discretization method is proposed and is implemented as a computer program for the modeling of a family of stirling type Pulse Tube Cryocoolers (PTC). The set of unsteady, one-dimensional, viscous compressible flow equations are written in a general form such that all, porous and non-porous, sections of the PTC can be modeled with these governing equations. In present work, temperature dependency of thermo-physical properties are taken into account as well as the heat transfer between the working fluid and the solid parts, and heat conductions of the gas and solid. The simulation tool can be used to model both the inertance tube type and the orifice type cryocoolers equipped with regenerators made up of different matrix constructions. The PTC might have an arbitrary orientation with respect to the gravitational field. By using the computer program, an orifice type and an inertance tube type pulse tube cryocooler are simulated. Diameter of the orifice and length of the inertance tube are optimized in order to maximize the coefficient of performance. Furthermore, the cooling power of the two types is obtained as a function of the cooling temperature. The behavior of thermodynamic parameters of the inertance tube PTC is investigated. Mean cyclic values of the parameters are presented.

  2. Real gas features on the performance of pulse tube cryocoolers

    Science.gov (United States)

    Ju, Y. L.

    2002-05-01

    The working helium gas in a pulse tube cryocooler operating at temperatures down to 80 K is mainly assumed to be an ideal gas. Therefore, the time-variations of the temperature profiles and the position of the gas element traveling with pressure oscillations inside the pulse tube can be readily determined by the law of Poisson function. However, this is certainly invalid for the pulse tube cryocooler operating at temperature range of liquid helium, in which the thermal properties of the helium gas change drastically. The temperature profiles in the regenerator and the pulse tube are strongly affected by the real thermal properties of the helium gas. We derive in this paper, the respective expressions to follow the tracks of the gas elements as they move in the pulse tube, and to reveal the time dependence of the temperature profiles and the position of gas elements traveling with the pressure oscillations inside the pulse tube. The approach is based on the thermodynamic equations for the real gas. We will show that contrary to the ideal gas case there is another term which determines the dynamic behaviors of the temperature distributions and the position of the gas elements. A typical calculation is presented for visualizing the time dependence of the cooling-down processes of the temperature profiles in the pulse tube of a 4K two-stage pulse tube cryocooler from room temperature down to low temperature.

  3. Space Stirling Cryocooler Contamination Lessons Learned and Recommended Control Procedures

    Science.gov (United States)

    Glaister, D. S.; Price, K.; Gully, W.; Castles, S.; Reilly, J.

    The most important characteristic of a space cryocooler is its reliability over a lifetime typically in excess of 7 years. While design improvements have reduced the probability of mechanical failure, the risk of internal contamination is still significant and has not been addressed in a consistent approach across the industry. A significant fraction of the endurance test and flight units have experienced some performance degradation related to internal contamination. The purpose of this paper is to describe and assess the contamination issues inside long life, space cryocoolers and to recommend procedures to minimize the probability of encountering contamination related failures and degradation. The paper covers the sources of contamination, the degradation and failure mechanisms, the theoretical and observed cryocooler sensitivity, and the recommended prevention procedures and their impact. We begin with a discussion of the contamination sources, both artificial and intrinsic. Next, the degradation and failure mechanisms are discussed in an attempt to arrive at a contaminant susceptibility, from which we can derive a contamination budget for the machine. This theoretical sensitivity is then compared with the observed sensitivity to illustrate the conservative nature of the assumed scenarios. A number of lessons learned on Raytheon, Ball, Air Force Research Laboratory, and NASA GSFC programs are shared to convey the practical aspects of the contamination problem. Then, the materials and processes required to meet the proposed budget are outlined. An attempt is made to present a survey of processes across industry.

  4. Jitter suppression techniques for mechanical cryocooler-induced disturbances

    Science.gov (United States)

    Wolfe, D. W.; Kirkconnell, C. S.; Fleischman, G. L.; Sunada, W. H.

    2008-08-01

    Closed-cycle mechanical cryogenic refrigerators, or cryocoolers, are an enabling technology for next generation infrared (IR) sensors. Passive cryoradiators and stored cryogen systems have been used successfully in the past, but the increased cooling requirements for emerging systems cannot practically be met with these passive techniques. Modern systems are employing much larger focal plane arrays that dissipate more energy and have higher parasitic thermal loads than in the past. Additional "on chip" FPA data processing capability, such as time delay and integration (TDI) and analog-to-digital conversion (ADC), is further driving up the heat loads. While loads are going up, temperatures are going down. The desire to operate at long wave infrared (LWIR) wavelengths (>9 microns) for a broader range of remote sensing missions is driving the need for 35-40 K refrigeration, significantly colder than past systems that operated at shorter wavelengths. Unfortunately, the use of a mechanical rather than passive cryocooler introduces an additional jitter source that must be properly mitigated. Techniques include the use of inherently low vibration cryocoolers, closedloop active vibration cancellation servo systems, damping struts, soft mounts, or a combination of these techniques. Implementation of these techniques within a proper system engineering context is presented.

  5. Attenuation of cryocooler induced vibration in spaceborne infrared payloads

    Science.gov (United States)

    Veprik, A.; Twitto, A.

    2014-01-01

    Recent advancement of operational responsive space programs calls for a development of compact, reliable, low power and vibration free cryogenic cooling for sophisticated infrared payloads. The refrigeration in a typical closed cycle split Stirling linear cryocooler is achieved by a cyclic compression and expansion of a gaseous working agent due to a synchronized reciprocation of electro-dynamically and pneumatically actuated compressor and expander pistons. Attenuation of the cryocooler induced vibration usually relies on the concept of actively assisted momentum cancellation. In a typical dual-piston compressor this objective is achieved by actively synchronizing the motion of oppositely moving piston assemblies; a typical single-piston expander may be counterbalanced by a motorized counter-balancer. The above approach produces complexity, weight, size, high incurred costs and affects reliability. The authors analyze the case of passive attenuation the vibration export induced by the split Stirling linear cryocooler comprised of inline mounted single-piston compressor and expander. Placement of all the moving components onto a common axis results in a single axis consolidation of vibration export and enables use of single tuned dynamic absorber and low frequency vibration mount. From theoretical analysis and full-scale testing, the performance of such vibration protection arrangement is similar to known systems of active vibration cancellation.

  6. Sorption product heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Antonini, G.; Francois, O.; Gendarme, J.P.; Guilleminot, J.J.; Meunier, F.

    1988-07-15

    A continuous operating, and thus with enhanced performance, heat pump is presented. In this heat pump, the heat transfer between the hot source and the output system or network is realized through a solid adsorbent-refrigerant couple having endothermal desorption properties and exothermal adsorption or absorption properties. The sorption products are carried in a closed cycle movement between the two parts of the reactor. Each side of the reactor is assuming always the same function and the thermal inertia have to be overcome only when starting the reactor.

  7. Ionic conduction of lithium hydride single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Pilipenko, G.I.; Oparin, D.V.; Zhuravlev, N.A.; Gavrilov, F.F.

    1987-09-01

    Using the electrical-conductivity- and NMR-measurement- methods, the ionic-conduction mechanism is established in stoichiometric lithium hydride single crystals. The activation energies of migration of anion- and cation-vacancies and the formation of Schottky-pair defects are determined. They assume that the mechanisms of self-diffusion and conductivity are different in lithium hydride.

  8. Submillimeter Spectroscopy of Hydride Molecules

    Science.gov (United States)

    Phillips, T. G.

    1998-05-01

    Simple hydride molecules are of great importance in astrophysics and astrochemistry. Physically they dominate the cooling of dense, warm phases of the ISM, such as the cores and disks of YSOs. Chemically they are often stable end points of chemical reactions, or may represent important intermediate stages of the reaction chains, which can be used to test the validity of the process. Through the efforts of astronomers, physicists, chemists, and laboratory spectroscopists we have an approximate knowledge of the abundance of some of the important species, but a great deal of new effort will be required to achieve the comprehensive and accurate data set needed to determine the energy balance and firmly establish the chemical pathways. Due to the low moment of inertia, the hydrides rotate rapidly and so have their fundamental spectral lines in the submillimeter. Depending on the cloud geometry and temperature profile they may be observed in emission or absorption. Species such as HCl, HF, OH, CH, CH(+) , NH_2, NH_3, H_2O, H_2S, H_3O(+) and even H_3(+) have been detected, but this is just a fraction of the available set. Also, most deduced abundances are not nearly sufficiently well known to draw definitive conclusions about the chemical processes. For example, the most important coolant for many regions, H_2O, has a possible range of deduced abundance of a factor of 1000. The very low submillimeter opacity at the South Pole site will be a significant factor in providing a new capabilty for interstellar hydride spectroscopy. The new species and lines made available in this way will be discussed.

  9. Facilitating protein crystal cryoprotection in thick-walled plastic capillaries by high-pressure cryocooling.

    Science.gov (United States)

    Chen, Yi-Fan; Tate, Mark W; Gruner, Sol M

    2009-06-01

    Many steps in the X-ray crystallographic solution of protein structures have been automated. However, the harvesting and cryocooling of crystals still rely primarily on manual handling, frequently with consequent mechanical damage. An attractive alternative is to grow crystals directly inside robust plastic capillaries that may be cryocooled and mounted on the beamline goniometer. In this case, it is still desirable to devise a way to cryoprotect the crystals, which is difficult owing to the poor thermal conductivity of thick plastic capillary walls and the large thermal mass of the capillary and internal mother liquor. A method is described to circumvent these difficulties. It is shown that high-pressure cryocooling substantially reduced the minimal concentrations of cryoprotectants required to cryocool water inside capillaries without formation of ice crystals. The minimal concentrations of PEG 200, PEG 400 and glycerol necessary for complete vitrification under pressure cryocooling were determined.

  10. Sorption Behaviours of Exfoliated Graphite

    Institute of Scientific and Technical Information of China (English)

    戴光泽; 伍川辉

    2002-01-01

    Exfoliated graphite (EG) is selected as a new kind of sorbent to sorb heavy oil spilled. In order to make use of EG more effectively, some basic experiments are performed to investigate its sorption properties,i.e., specific sorption, height of saturation layer, sorption time constant. In the present experiments, A-grade heavy oil is employed as a standard sorbate. It is concluded that 1) under the condition that the area of solid (filter bottom)-liquid (heavy oil) interface is a constant, specific sorption usually decreases when the amount of EG filled or the apparent bulk density increase; however, the specific sorption initially increases when the apparent bulk density is too low and the amount of EG filled is too much; 2) under the condition that the apparent bulk density of EG filled is a constant, the sorption time constant tends to increase when the amount of EG filled increases; however, for a constant amount of EG filled, the sorption time constant will decrease when the apparent bulk density increases.

  11. Hydride heat pump with heat regenerator

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative hydride heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system. A series of at least four canisters containing a lower temperature performing hydride and a series of at least four canisters containing a higher temperature performing hydride is provided. Each canister contains a heat conductive passageway through which a heat transfer fluid is circulated so that sensible heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  12. Sorption isotherms and isosteric heats of sorption of Malaysian paddy.

    Science.gov (United States)

    Mousa, Wael; Ghazali, Farinazleen Mohamad; Jinap, S; Ghazali, Hasanah Mohd; Radu, Son

    2014-10-01

    Understanding the water sorption characteristics of cereal is extremely essential for optimizing the drying process and ensuring storage stability. Water relation of rough rice was studied at 20, 30, 40 and 50 °C over relative humidity (RH.) between 0.113 and 0.976 using the gravimetric technique. The isotherms displayed the general sigmoid, Type II pattern and exhibited the phenomenon of hysteresis where it was more pronounced at lower temperatures. The sorption characteristics were temperature dependence where the sorption capacity of the paddy increased as the temperature was decreased at fixed (RH). Among the models assessed for their ability to fit the sorption data, Oswin equation was the best followed by the third order polynomial, GAB, Smith, Chung-Pfost, and Henderson models. The monolayer moisture content was higher for desorption than adsorption and tend to decrease with the increase in temperature. Given the temperature dependence of the sorption isotherms the isosteric heats of sorption were calculated using Claussius-Clapeyron equation. The net isosteric heats decreased as the moisture content was increased and heats of desorption were greater than that of adsorption.

  13. Design, development and testing twin pulse tube cryocooler

    Science.gov (United States)

    Gour, Abhay Singh; Sagar, Pankaj; Karunanithi, R.

    2017-09-01

    The design and development of Twin Pulse Tube Cryocooler (TPTC) is presented. Both the coolers are driven by a single Linear Moving Magnet Synchronous Motor (LMMSM) with piston heads at both ends of the mover shaft. Magnetostatic analysis for flux line distribution was carried-out during design and development of LMMSM based pressure wave generator. Based on the performance of PWG, design of TPTC was carried out using Sage and Computational Fluid Dynamics (CFD) analysis. Detailed design, fabrication and testing of LMMSM, TPTC and their integration tests are presented in this paper.

  14. Erbium-based magnetic refrigerant (regenerator) for passive cryocooler

    Science.gov (United States)

    Gschneidner, Jr., Karl A.; Pecharsky, Vitalij K.

    1996-07-23

    A two stage Gifford-McMahon cryocooler having a low temperature stage for reaching approximately 10K, wherein the low temperature stage includes a passive magnetic heat regenerator selected from the group consisting of Er.sub.6 Ni.sub.2 Sn, Er.sub.6 Ni.sub.2 Pb, Er.sub.6 Ni.sub.2 (Sn.sub.0.75 Ga.sub.0.25), and Er.sub.9 Ni.sub.3 Sn comprising a mixture of Er.sub.3 Ni and Er.sub.6 Ni.sub.2 Sn in the microstructure.

  15. Cool Down Analysis of a Cryocooler Based Quadrupole Magnet Cryostat

    Science.gov (United States)

    Choudhury, A.; Kar, S.; Chacko, J.; Kumar, M.; Babu, S.; Sahu, S.; Kumar, R.; Antony, J.; Datta, T. S.

    A superconducting quadrupole doublet magnet with cold superferric iron cover for the Hybrid Recoil Mass Analyzer (HYRA) beam line has been commissioned. The total cold mass of the helium vessel with iron yoke and pole is 2 ton. A set of two Sumitomo cryocoolers take care of various heat loads to the cryostat. The first successful cool down of the cryostat has been completed recently, magnets have been powered and magnetic field profiling has been done inside theroom temperature beam tube. This paper will highlight the cryostat details along with the cool down and operational test results obtained from the first cool down.

  16. Multi-axis analog adaptive feedforward cancellation of cryocooler vibration

    Science.gov (United States)

    Collins, Simon Andrew

    1994-01-01

    The vibration produced by Stirling cryocoolers is incompatible with spacecraft-borne precision-pointing imaging instruments. Thermal considerations prevent the addition of sufficient mechanical isolation to eliminate the effects of this vibration. The objective of this research is the design, analysis, and experimental verification of a multi-axis vibration cancellation system for the expander of a split Stirling cryocooler. Cancellation of the periodic cryocooler vibration is achieved with a set of load cells, a custom three-axis electrodynamic actuator, and a narrowband adaptive feedforward controller. In order to size the actuator, a simple model of the cryocooler's vibration is combined with a first-order analysis of a four-magnet two-return-plate forcing element. While the resulting actuator has sufficient force capability, it exhibits significant nonlinearity. A nonlinear actuator model is developed that accounts for in-plane flexure restraint due to both large-amplitude static deflections and large-amplitude vibrations. Numerical solutions of the nonlinear model accurately reflect jump phenomena and higher harmonics observed in the actuator's response. The adaptive feedforward controller employs the filtered-x least-mean-square (FXLMS) algorithm to update an adaptive filter. Rather than implementing this filter with a digital signal processor (DSP), for which there is little flight heritage, a continuous-time analog realization of the FXLMS filter is selected. Theoretically, the FXLMS filter may be represented by an equivalent linear transfer function. However a comprehensive treatment of factors associated with the actual implementation reveals the limitations of the transfer function representation. Factors such as harmonic distortion of the reference signal and imperfect quadrature are shown to result in frequency-shifted terms in the filter's output. The presence of these output components is confirmed experimentally, and their effect on performance is

  17. Cryogenic characterization of the Planck sorption cooler system flight model

    CERN Document Server

    Morgante, G; Melot, F; Stassi, P; Terenzi, L; Wilson, P; Hernandez, B; Wade, L; Gregorio, A; Bersanelli, M; Butler, C; Mandolesi, N; 10.1088/1748-0221/4/12/T12016

    2009-01-01

    This paper is part of the Prelaunch status LFI papers published on JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/1748-0221 Two continuous closed-cycle hydrogen Joule-Thomson (J-T) sorption coolers have been fabricated and assembled by the Jet Propulsion Laboratory (JPL) for the European Space Agency (ESA) Planck mission. Each refrigerator has been designed to provide a total of ~ 1W of cooling power at two instrument interfaces: they directly cool the Planck Low Frequency Instrument (LFI) around 20K while providing a pre-cooling stage for a 4 K J-T mechanical refrigerator for the High Frequency Instrument (HFI). After sub-system level validation at JPL, the cryocoolers have been delivered to ESA in 2005. In this paper we present the results of the cryogenic qualification and test campaigns of the Nominal Unit on the flight model spacecraft performed at the CSL (Centre Spatial de Liege) facilities in 2008. Test results in terms of input power, cooling power, temperature, and temperature fluctuations o...

  18. Cryogenic characterization of the Planck sorption cooler system flight model

    Energy Technology Data Exchange (ETDEWEB)

    Morgante, G; Terenzi, L; Butler, C; Mandolesi, N [INAF - IASF Bologna, via P. Gobetti 101, 40129 Bologna (Italy); Pearson, D; Wilson, P; Hernandez, B; Wade, L [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena California 91109 (United States); Melot, F; Stassi, P [Laboratoire de Physique Subatomique et de Cosmologie 53 Avenue des Martyrs, 38026 Grenoble Cedex (France); Gregorio, A [Dipartimento di Fisica, Universita degli Studi di Trieste, via Valerio 2 - I-34127 Trieste (Italy); Bersanelli, M, E-mail: morgante@iasfbo.inaf.i [Dipartimento di Fisica, Universita degli Studi di Milano, via Celoria 16, - I20133 Milano (Italy)

    2009-12-15

    Two continuous closed-cycle hydrogen Joule-Thomson (J-T) sorption coolers have been fabricated and assembled by the Jet Propulsion Laboratory (JPL) for the European Space Agency (ESA) Planck mission. Each refrigerator has been designed to provide a total of {approx} 1W of cooling power at two instrument interfaces: they directly cool the Planck Low Frequency Instrument (LFI) around 20K while providing a pre-cooling stage for a 4 K J-T mechanical refrigerator for the High Frequency Instrument (HFI). After sub-system level validation at JPL, the cryocoolers have been delivered to ESA in 2005. In this paper we present the results of the cryogenic qualification and test campaigns of the Nominal Unit on the flight model spacecraft performed at the CSL (Centre Spatial de Liege) facilities in 2008. Test results in terms of input power, cooling power, temperature, and temperature fluctuations over the flight allowable ranges for these interfaces are reported and analyzed with respect to mission requirements.

  19. Body centered cubic magnesium niobium hydride with facile room temperature absorption and four weight percent reversible capacity.

    Science.gov (United States)

    Tan, XueHai; Wang, Liya; Holt, Chris M B; Zahiri, Beniamin; Eikerling, Michael H; Mitlin, David

    2012-08-21

    We have synthesized a new metastable metal hydride with promising hydrogen storage properties. Body centered cubic (bcc) magnesium niobium hydride (Mg(0.75)Nb(0.25))H(2) possesses 4.5 wt% hydrogen gravimetric density, with 4 wt% being reversible. Volumetric hydrogen absorption measurements yield an enthalpy of hydride formation of -53 kJ mol(-1) H(2), which indicates a significant thermodynamic destabilization relative to the baseline -77 kJ mol(-1) H(2) for rutile MgH(2). The hydrogenation cycling kinetics are remarkable. At room temperature and 1 bar hydrogen it takes 30 minutes to absorb a 1.5 μm thick film at sorption cycle 1, and 1 minute at cycle 5. Reversible desorption is achieved in about 60 minutes at 175 °C. Using ab initio calculations we have examined the thermodynamic stability of metallic alloys with hexagonal close packed (hcp) versus bcc crystal structure. Moreover we have analyzed the formation energies of the alloy hydrides that are bcc, rutile or fluorite.

  20. Hydrogen storage in complex metal hydrides

    National Research Council Canada - National Science Library

    Bogdanovic, Borislav; Felderhoff, Michael; Streukens, Guido

    2009-01-01

    ...) are solid-state hydrogen-storage materials with high hydrogen capacities. They can be used in combination with fuel cells as a hydrogen source thus enabling longer operation times compared with classical metal hydrides...

  1. Method of forming metal hydride films

    Science.gov (United States)

    Steinberg, R.; Alger, D. L.; Cooper, D. W. (Inventor)

    1977-01-01

    The substrate to be coated (which may be of metal, glass or the like) is cleaned, both chemically and by off-sputtering in a vacuum chamber. In an ultra-high vacuum system, vapor deposition by a sublimator or vaporizer coats a cooled shroud disposed around the substrate with a thin film of hydride forming metal which getters any contaminant gas molecules. A shutter is then opened to allow hydride forming metal to be deposited as a film or coating on the substrate. After the hydride forming metal coating is formed, deuterium or other hydrogen isotopes are bled into the vacuum system and diffused into the metal film or coating to form a hydride of metal film. Higher substrate temperatures and pressures may be used if various parameters are appropriately adjusted.

  2. Sealed aerospace metal-hydride batteries

    Science.gov (United States)

    Coates, Dwaine

    1992-01-01

    Nickel metal hydride and silver metal hydride batteries are being developed for aerospace applications. There is a growing market for smaller, lower cost satellites which require higher energy density power sources than aerospace nickel-cadmium at a lower cost than space nickel-hydrogen. These include small LEO satellites, tactical military satellites and satellite constellation programs such as Iridium and Brilliant Pebbles. Small satellites typically do not have the spacecraft volume or the budget required for nickel-hydrogen batteries. NiCd's do not have adequate energy density as well as other problems such as overcharge capability and memory effort. Metal hydride batteries provide the ideal solution for these applications. Metal hydride batteries offer a number of advantages over other aerospace battery systems.

  3. Probing the cerium/cerium hydride interface using nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Brierley, Martin, E-mail: martin.brierley@awe.co.uk [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom); University of Manchester, Manchester M13 9PL (United Kingdom); Knowles, John, E-mail: john.knowles@awe.co.uk [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom)

    2015-10-05

    Highlights: • A disparity exists between the minimum energy and actual shape of a cerium hydride. • Cerium hydride is found to be harder than cerium metal by a ratio of 1.7:1. • A zone of material under compressive stress was identified surrounding the hydride. • No distribution of hardness was apparent within the hydride. - Abstract: A cerium hydride site was sectioned and the mechanical properties of the exposed phases (cerium metal, cerium hydride, oxidised cerium hydride) were measured using nanoindentation. An interfacial region under compressive stress was observed in the cerium metal surrounding a surface hydride that formed as a consequence of strain energy generated by the volume expansion associated with precipitation of the hydride phase.

  4. Effects of cyclic mean pressure of helium gas on performance of integral crank driven stirling cryocooler

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Yong Ju; Ko, Jun Seok; Kim, Hyo Bong; Park, Seong Je [Korea Institute of Machinery and Materials, Changwon (Korea, Republic of)

    2016-09-15

    An integral crank driven Stirling cryocooler is solidly based on concepts of direct IR detector mounting on the cryocooler's cold finger, and the integral construction of the cryocooler and Dewar envelope. Performance factors of the cryocooler depend on operating conditions of the cryocooler such as a cyclic mean pressure of the working fluid, a rotational speed of driving mechanism, a thermal environment, a targeted operation temperature and etc.. At given charging condition of helium gas, the cyclic mean pressure of helium gas in the cryocooler changes with temperatures of the cold end and the environment. In this study, effects of the cyclic mean pressure of helium gas on performances of the Stirling cryocooler were investigated by numerical analyses using the Sage software. The simulation model takes into account thermodynamic losses due to an inefficiency of regenerator, a pressure drop, a shuttle heat transfer and solid conductions. Simulations are performed for the performance variation according to the cyclic mean pressure induced by the temperature of the cold end and the environment. This paper presents P-V works in the compression and expansion space, cooling capacity, contribution of losses in the expansion space.

  5. Air Force Research Laboratory Spacecraft Cryocooler Endurance Evaluation Facility Closing Report

    Science.gov (United States)

    Armstrong, J.; Martin, K. W.; Fraser, T.

    2015-12-01

    The Air Force Research Laboratory (AFRL) Spacecraft Component Thermal Research Group has been devoted to evaluating lifetime performance of space cryocooler technology for over twenty years. Long-life data is essential for confirming design lifetimes for space cryocoolers. Continuous operation in a simulated space environment is the only accepted method to test for degradation. AFRL has provided raw data and detailed evaluations to cryocooler developers for advancing the technology, correcting discovered deficiencies, and improving cryocooler designs. At AFRL, units of varying design and refrigeration cycles were instrumented in state-of-the-art experiment stands to provide spacelike conditions and were equipped with software data acquisition to track critical cryocooler operating parameters. This data allowed an assessment of the technology's ability to meet the desired lifetime and documented any long-term changes in performance. This paper will outline a final report of the various flight cryocoolers tested in our laboratory. The data summarized includes the seven cryocoolers tested during 2014-2015. These seven coolers have a combined total of 433,326 hours (49.5 years) of operation.

  6. Preparation and hydrogen sorption properties of Mg-Cu-Y-H systems

    Institute of Scientific and Technical Information of China (English)

    LI Zhinian; LIU Xiaopeng; HUANG Zuo; JIANG Lijun; WANG Shumao

    2006-01-01

    Mg-xwt.%CuY (x=15, 20, 25) composites were successfully prepared by reactive mechanical alloying (RMA).X-ray diffraction (XRD) measurement shows that main phases of the as milled composites are MgH2 and Mg2Cu, and they converted into Mg and MgCu2 after dehydrogenation, respectively.Pressure-Composition-Isotherm (PCI) test shows that the composites exhibit double pressure plateau at each isothermal desorption process.The hydrogen absorption and desorption kinetics of the composites become worse with increasing x content, indicating that Mg-Cu phase has a negative effect on the hydrogen sorption properties of the composites.It is supposed that the good hydrogen sorption properties of the composites attribute to the catalyst effect of yttrium hydride distributed in Mg substrate and the particles size reduction and crystal defects formed by RMA.

  7. Application of Severe Plastic Deformation Techniques to Magnesium for Enhanced Hydrogen Sorption Properties

    Directory of Open Access Journals (Sweden)

    Daniel Fruchart

    2012-08-01

    Full Text Available In this paper we review the latest developments in the use of severe plastic deformation (SPD techniques for enhancement of hydrogen sorption properties of magnesium and magnesium alloys. Main focus will be on two techniques: Equal Channel Angular Pressing (ECAP and Cold Rolling (CR. After a brief description of these two techniques we will discuss their effects on the texture and hydrogen sorption properties of magnesium alloys. In particular, the effect of the processing temperature in ECAP on texture will be demonstrated. We also show that ECAP and CR have produced different textures. Despite the scarcity of experimental results, the investigations up to now indicate that SPD techniques produce metal hydrides with enhanced hydrogen storage properties.

  8. Cryocooled Facilities for Superconducting Coils Testing in Gaseous Helium

    Science.gov (United States)

    Naumov, A. V.; Keilin, V. E.; Kovalev, I. A.; Surin, M. I.; Shcherbakov, V. I.; Shevchenko, S. A.; Ilin, A. A.

    Two superconducting coil test facilities equipped by Sumitomo SRDK-415D cryocoolers were developed, manufactured and tested. The motivation for their constructing was to make cheaper the testing (and especially training of LTS magnets) by liquid helium (LHe) saving. It is well known that the helium price increases rapidly and this tendency most probably will continue for a long time, as the demand of helium grows faster than its production. The utilization of heat-exchange gas considerably reduces many problems, that arise in the design of completely dry LTS magnets. The goal was to decrease or even completely avoid the consumption of rather expensive liquid helium for testing the laboratory size Nb-Ti and Nb3Sn coils including their training process. Several superconducting magnets were tested by using these facilities. For example, the first facility was successfully used for testing of 13 T, 60 kg coil cooled by cryocooler in helium gas (several torr pressure) heat exchange atmosphere. The precooling time was about 45 hours. The quench current (240 A at 4.2 K) was equal to that reached in the pool boiling LHe cryostat. The second facility with 420 mm wide access bore can be used for testing of corresponding size superconducting coils with very modest consumption of liquid helium with its level well below the lower flange of the coil. Each test facility is equipped by 2 pairs of HTS current leads. Design and operational experience of one of them is described.

  9. Cryocooler operation of SNIS Josephson arrays for AC Voltage standards

    Science.gov (United States)

    Sosso, A.; De Leo, N.; Fretto, M.; Monticone, E.; Roncaglione, L.; Rocci, R.; Lacquaniti, V.

    2014-05-01

    Avoiding liquid helium is now a worldwide issue, thus cryocooler operation is becoming mandatory for a wider use of superconductive electronics. Josephson voltage standards hold a peculiar position among superconducting devices, as they are in use in high precision voltage metrology since decades. Higher temperature operation would reduce the refrigerator size and complexity, however, arrays of Josephson junctions made with high temperature superconductors for voltage standard applications are not to date available. The SNIS (Superconductor-Normal metal-Insulator-Superconductor) junction technology developed at INRIM, based on low temperature superconductors, but capable of operation well above liquid helium temperature, is interesting for application to a compact cryocooled standard, allowing to set a compromise between device and refrigerator requirements. In this work, the behavior of SNIS devices cooled with a closed-cycle refrigerator has been investigated, both in DC and under RF irradiation. Issues related to thermal design of the apparatus to solve specific problems not faced with liquid coolants, like reduced cooling power and minimization of thermal gradients for uniform operation of the chip are discussed in detail.

  10. Performance and reliability characteristic of Stirling cryocoolers in China

    Science.gov (United States)

    Liu, X. G.; Wu, Y. N.; He, L.

    2008-03-01

    With extensive application of infrared detective techniques, Stirling cryocoolers, used as an active cooling source, have been developed vigorously in China. An overview of the status and performance for some Stirling cryocoolers having been developed is presented. To analyze the cooler's reliability characteristic, failure analysis has been done, and the four crucial failure modes affecting cooler's long-life running are wear, gaseous contamination, Helium leakage and fatigue. According to each failure mechanism, the measures taken to control or minimize its damage were discussed, and some experiments were designed and carried to quantitatively analyze the relationship between failure and performance in detail. To the wear, an ageing test, which was thermal cycle and for about 500 h, was used to improve the internal frication status and eliminate the defective products. To the gaseous contamination, an accelerated experiment was carried by adding contaminants to the cooler by a 3-way valve to get the relationship between performance degradation and amount of contaminants. The chance of a fatigue related failure is very small now because of the FEM analysis and screening test. Based on charge pressure experiment results, the criteria to judge the sealing procedure was given by the ratio of leak rate to cooler volume.

  11. Study of Random Wire Type Regenerators for Stirling Cryocoolers

    Science.gov (United States)

    Jeong, Sangkwon; Nam, Kwanwoo; Choi, Sungryel

    2004-06-01

    This paper describes the performance evaluation for the random wire type regenerator used in Stirling cryocoolers. Metallic and non-metallic regenerators are tested and analyzed. Non-metallic regenerator we test is made of high-temperature resistant polymer. First, the ineffectiveness is determined by measuring the instantaneous pressure, the flow rate and the gas temperature at both ends of the regenerator. The cold-end temperature is maintained around 100 K and the operating frequency is fixed at 60 Hz. It is found that the non-metallic regenerator with high heat transfer area has a low ineffectiveness even though its volumetric heat capacity is lower than the metallic regenerator. Second, dynamic analysis is performed for the displacer of Stirling cryocooler containing the above regenerators. Oscillating flow model is proposed to accurately predict the pressure drop through the regenerator. Amplitude and phase angle of the displacer are calculated both from the oscillating flow model and the steady flow model. Superiority of the proposed oscillating flow model is demonstrated by the comparison between the analysis result and the experimental measurements.

  12. Scaling STI's sapphire cryocooler for applications requiring higher heat loads

    Science.gov (United States)

    Karandikar, Abhijit; Fiedler, Andreas

    2012-06-01

    Superconductor Technologies Inc. (STI) developed the Sapphire cryocooler specifically for the SuperLink® product; a high performance superconducting Radio Frequency (RF) front-end receiver used by wireless carriers such as Verizon Wireless and AT&T to improve network cell coverage and data speeds. STI has built and deployed over 6,000 systems operating 24 hours a day (24/7), 7 days a week in the field since 1999. Sapphire is an integrated free piston Stirling cycle cryocooler with a cooling capacity of 5 Watts at 77 Kelvin (K) with less than 100 Watts (W) input power. It has a field-proven Mean Time Between Failure (MTBF) of well over 1 million hours, requires zero maintenance and has logged over 250 million cumulative runtime hours. The Sapphire cooler is built on a scalable technology platform, enabling the design of machines with cooling capacities greater than 1 kilowatt (kW). This scalable platform also extends the same outstanding attributes as the Sapphire cooler, namely high reliability, zero maintenance, and compact size - all at a competitive cost. This paper will discuss emerging applications requiring higher heat loads and these attributes, describe Sapphire, and show a preliminary concept of a scaled machine with a 100 W cooling capacity.

  13. Design of an improved high cooling power 4 K GM cryocooler and helium compressor

    Science.gov (United States)

    Hao, X. H.

    2015-12-01

    High cooling power 4 K cryocoolers are in high demand given their broad applications in such fields as magnetic resonance imaging (MRI) and low temperature superconductors. ARS has recently designed and developed a high cooling power 4 K pneumatic-drive GM cryocooler which achieves a typical cooling power of 1.75 W/4.2 K. Steady input power of our newly developed helium compressor supplied to the cold head is 11.8 kW at 60 Hz. The operational speed of the cold head is 30 RPM. The effects of geometries and operational conditions on the cooling performance of this 4 K GM cryocooler are also experimentally tested.

  14. Development of a linear compressor for two-stage pulse tube cryocoolers

    Institute of Scientific and Technical Information of China (English)

    Peng-da YAN; Wei-li GAO; Guo-bang CHEN

    2009-01-01

    A valveless linear compressor was built up to drive a self-made two-stage pulse tube cryocooler. With a designed maximum swept volume of 60 cm~3, the compressor can provide the cryocooler with a pressure volume (PV) power of 400 W.Preliminary measurements of the compressor indicated that both an efficiency of 35%~55% and a pressure ratio of 1.3~1.4 could be obtained. The two-stage pulse tube cryocooler driven by this compressor achieved the lowest temperature of 14.2 K.

  15. A critical review of liquid helium temperature high frequency pulse tube cryocoolers for space applications

    Science.gov (United States)

    Wang, B.; Gan, Z. H.

    2013-08-01

    The importance of liquid helium temperature cooling technology in the aerospace field is discussed, and the results indicate that improving the efficiency of liquid helium cooling technologies, especially the liquid helium high frequency pulse tube cryocoolers, is the principal difficulty to be solved. The state of the art and recent developments of liquid helium high frequency pulse tube cryocoolers are summarized. The main scientific challenges for high frequency pulse tube cryocoolers to efficiently reach liquid helium temperatures are outlined, and the research progress addressing those challenges are reviewed. Additionally some possible solutions to the challenges are pointed out and discussed.

  16. Development of a Novel Brayton-Cycle Cryocooler and Key Component Technologies

    Science.gov (United States)

    Nieczkoski, S. J.; Mohling, R. A.

    2004-06-01

    Brayton-cycle cryocoolers are being developed to provide efficient cooling in the 6 K to 70 K temperature range. The cryocoolers are being developed for use in space and in terrestrial applications where combinations of long lifetime, high efficiency, compactness, low mass, low vibration, flexible interfacing, load variability, and reliability are essential. The key enabling technologies for these systems are a mesoscale expander and an advanced oil-free scroll compressor. Both these components are nearing completion of their prototype development phase. The emphasis on the component and system development has been on invoking fabrication processes and techniques that can be evolved to further reduction in scale tending toward cryocooler miniaturization.

  17. gamma-Zr-Hydride Precipitate in Irradiated Massive delta- Zr-Hydride

    DEFF Research Database (Denmark)

    Warren, M. R.; Bhattacharya, D. K.

    1975-01-01

    During examination of A Zircaloy-2-clad fuel pin, which had been part of a test fuel assembly in a boiling water reactor, several regions of severe internal hydriding were noticed in the upper-plenum end of the pin. Examination of similar fuel pins has shown that hydride of this type is caused...

  18. The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components Delayed Hydride Cracking

    CERN Document Server

    Puls, Manfred P

    2012-01-01

    By drawing together the current theoretical and experimental understanding of the phenomena of delayed hydride cracking (DHC) in zirconium alloys, The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components: Delayed Hydride Cracking provides a detailed explanation focusing on the properties of hydrogen and hydrides in these alloys. Whilst the focus lies on zirconium alloys, the combination of both the empirical and mechanistic approaches creates a solid understanding that can also be applied to other hydride forming metals.   This up-to-date reference focuses on documented research surrounding DHC, including current methodologies for design and assessment of the results of periodic in-service inspections of pressure tubes in nuclear reactors. Emphasis is placed on showing that our understanding of DHC is supported by progress across a broad range of fields. These include hysteresis associated with first-order phase transformations; phase relationships in coherent crystalline metallic...

  19. A review of recent advances on the effects of microstructural refinement and nano-catalytic additives on the hydrogen storage properties of metal and complex hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Varin, R. A.; Zbroniec, L. [University of Waterloo, Department of Mechanical and Mechatronics Engineering, Waterloo, Ontario (Canada); Polanski, M.; Bystrzycki, J. [Faculty of Advanced Technology and Chemistry, Military University of Technology, Warsaw (Poland)

    2011-07-01

    The recent advances on the effects of microstructural refinement and various nano-catalytic additives on the hydrogen storage properties of metal and complex hydrides obtained in the last few years in the allied laboratories at the University of Waterloo (Canada) and Military University of Technology (Warsaw, Poland) are critically reviewed in this paper. The research results indicate that microstructural refinement (particle and grain size) induced by ball milling influences quite modestly the hydrogen storage properties of simple metal and complex metal hydrides. On the other hand, the addition of nanometric elemental metals acting as potent catalysts and/or metal halide catalytic precursors brings about profound improvements in the hydrogen absorption/desorption kinetics for simple metal and complex metal hydrides alike. In general, catalytic precursors react with the hydride matrix forming a metal salt and free nanometric or amorphous elemental metals/intermetallics which, in turn, act catalytically. However, these catalysts change only kinetic properties i.e. the hydrogen absorption/desorption rate but they do not change thermodynamics (e.g., enthalpy change of hydrogen sorption reactions). It is shown that a complex metal hydride, LiAlH{sub 4}, after high energy ball milling with a nanometric Ni metal catalyst and/or MnCl{sub 2} catalytic precursor, is able to desorb relatively large quantities of hydrogen at room temperature, 40 and 80 {sup o}C. This kind of behavior is very encouraging for the future development of solid state hydrogen systems. (authors)

  20. A Review of Recent Advances on the Effects of Microstructural Refinement and Nano-Catalytic Additives on the Hydrogen Storage Properties of Metal and Complex Hydrides

    Directory of Open Access Journals (Sweden)

    Jerzy Bystrzycki

    2010-12-01

    Full Text Available The recent advances on the effects of microstructural refinement and various nano-catalytic additives on the hydrogen storage properties of metal and complex hydrides obtained in the last few years in the allied laboratories at the University of Waterloo (Canada and Military University of Technology (Warsaw, Poland are critically reviewed in this paper. The research results indicate that microstructural refinement (particle and grain size induced by ball milling influences quite modestly the hydrogen storage properties of simple metal and complex metal hydrides. On the other hand, the addition of nanometric elemental metals acting as potent catalysts and/or metal halide catalytic precursors brings about profound improvements in the hydrogen absorption/desorption kinetics for simple metal and complex metal hydrides alike. In general, catalytic precursors react with the hydride matrix forming a metal salt and free nanometric or amorphous elemental metals/intermetallics which, in turn, act catalytically. However, these catalysts change only kinetic properties i.e. the hydrogen absorption/desorption rate but they do not change thermodynamics (e.g., enthalpy change of hydrogen sorption reactions. It is shown that a complex metal hydride, LiAlH4, after high energy ball milling with a nanometric Ni metal catalyst and/or MnCl2 catalytic precursor, is able to desorb relatively large quantities of hydrogen at RT, 40 and 80 °C. This kind of behavior is very encouraging for the future development of solid state hydrogen systems.

  1. Preliminary development of flaw evaluation procedures for delayed hydride cracking initiation under hydride non-ratcheting conditions

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S.; Cui, J.; Kawa, D.; Shek, G.K.; Scarth, D.A. [Kinectrics Inc., Toronto, Ontario (Canada)

    2006-07-01

    The flaw evaluation procedure for Delayed Hydride Cracking (DHC) initiation currently provided in the CSA Standard N285.8 was developed for hydride ratcheting conditions, in which flaw-tip hydrides do not completely dissolve at peak temperature. Test results have shown that hydrided regions formed under non-ratcheting conditions, in which flaw-tip hydrides completely dissolve at peak temperature, have significantly higher resistance to cracking than those formed under ratcheting conditions. This paper presents some preliminary work on the development of a procedure for the evaluation of DHC initiation for flaws under hydride non-ratcheting conditions. (author)

  2. Development of Thermoelectric Power Generation and Peltier Cooling Properties of Materials for Thermoelectric Cryocooling Devices

    Science.gov (United States)

    2015-05-12

    Distribution Unlimited Final Report: Development of Thermoelectric Power Generation and Peltier Cooling Properties of Materials for Thermoelectric...Thermoelectric Power Generation and Peltier Cooling Properties of Materials for Thermoelectric Cryocooling Devices Report Title The research

  3. Development of a 77K Reverse-Brayton Cryocooler with Multiple Coldheads Project

    Data.gov (United States)

    National Aeronautics and Space Administration — RTI will design and optimize an 80 W, 77K cryocooler based on the reverse turbo Brayton cycle (RTBC) with four identical coldheads for distributed cooling. Based on...

  4. A high-efficiency coaxial pulse tube cryocooler with 500 W cooling capacity at 80 K

    Science.gov (United States)

    Hu, J. Y.; Zhang, L. M.; Zhu, J.; Chen, S.; Luo, E. C.; Dai, W.; Li, H. B.

    2014-07-01

    High-temperature superconductivity power-grid technologies require a highly reliable and efficient cryocooler with cooling power of 100 W to kilowatt level at liquid-nitrogen temperatures to produce cryogenic environments. This paper describes the design of a coaxial Stirling-type pulse tube cryocooler to meet this need. In the designed cryocooler, the regenerator and pulse tube are lengthened to avoid possible temperature inhomogeneity. In an experiment, the azimuthal temperature difference at the middle of the regenerator was less than 30 K. With 7.6 kW electric power input, the cryocooler offers more than 520 W cooling power at 80 K corresponding to a relative Carnot efficiency of 18.2%. When the cooling power was less than 370 W, the efficiency is higher than 20%.

  5. PERFORMANCE ENHANCEMENT OF A MINIATURE STIRLING CRYOCOOLER WITH A MULTI MESH REGENERATOR DESIGN

    National Research Council Canada - National Science Library

    KISHOR KUMAR V. V; BIJU T. KUZHIVELI

    2017-01-01

    A parametric study has been carried out using the software REGEN 3.3 to optimize the regenerator of a miniature Stirling cryocooler operating with a warm end temperature of 300 K and cold end temperature of 80 K...

  6. Advanced, Long-Life Cryocooler Technology for Zero-Boil-Off Cryogen Storage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Long-life, high-capacity cryocoolers are a critical need for future space systems utilizing stored cryogens. The cooling requirements for planetary and...

  7. High efficiency linear compressor driven pulse tube cryocooler operating in liquid nitrogen temperature

    Institute of Scientific and Technical Information of China (English)

    HU JianYing; WANG XiaoTao; DAI Wei; LUO ErCang; HUANG Yu

    2009-01-01

    The inertance tube is one of the key components of a pulse tube cryocooler. It has great influence not only on the efficiency of the pulse tube cryocooler, but also on the efficiency of the linear compressor. Meanwhile, it is very difficult to predict the impedance of an inertance tube because of the turbulent flow. In this paper, using a quasi-turbulent model, the inertance tube is optimized to match a linear compressor driven pulse tube cryocooler. Experimental results show that this model can predict the impedance quite well. With 127 W input electric power, the pulse tube cryocooler obtains 9.4 W cooling power at a temperature of 77 K. The relative Carnot efficiency of the whole system reaches 19.8%.

  8. A three-stage Stirling pulse tube cryocooler operating below the critical point of helium-4

    Science.gov (United States)

    Qiu, L. M.; Cao, Q.; Zhi, X. Q.; Gan, Z. H.; Yu, Y. B.; Liu, Y.

    2011-10-01

    Precooled phase shifters can significantly enhance the phase shift effect and further improve the performance of pulse tube cryocoolers. A separate three-stage Stirling pulse tube cryocooler (SPTC) with a cold inertance tube was designed and fabricated. Helium-4 instead of the rare helium-3 was used as the working fluid. The cryocooler reached a bottom temperature of 4.97 K with a net cooling power of 25 mW at 6.0 K. The operating frequency was 29.9 Hz and the charging pressure was 0.91 MPa. It is the first time a refrigeration temperature below the critical point of helium-4 was obtained in a three-stage Stirling pulse tube cryocooler.

  9. Study on a pulse tube cryocooler using gas mixture as its working fluid

    Science.gov (United States)

    Gao, C. M.; He, Y. L.; Chen, Z. Q.

    2000-01-01

    In order to improve the performance of a one-stage pulse tube cryocooler, gas mixtures are used for comparison, which have been used in other cryocoolers. A mixture of hydrogen and helium was investigated in this study. When the structure of the pulse tube is the same as mentioned in [C. Wang, P.Y. Wu, Zh.Q. Chen, Numerical modeling of an orifice pulse tube cryocooler, Cryogenics 32 (1992) 785] and the working conditions are: frequency 15 Hz, average pressure 1.1 MPa, hot end temperature 300 K and cold end temperature 80 K, it has been found that there are optimal molar percentage for the maximal cooling power and the maximal-coefficient of performance (COP) of this cryocooler.

  10. Transient analysis of single stage GM type double inlet pulse tube cryocooler

    Science.gov (United States)

    Gujarati, P. B.; Desai, K. P.; Naik, H. B.; Atrey, M. D.

    2015-12-01

    Transient analysis of single stage GM type double inlet pulse tube cryocooler is carried out using a one dimensional numerical model based on real gas properties of helium. The model solves continuity, momentum and energy equation for gas and solid to analyse the physical process occurring inside of the pulse tube cryocooler. Finite volume method is applied to discretize the governing equations with realistic initial and boundary conditions. Input data required for solving the model are the design data and operating parameters viz. pressure waveform from the compressor, regenerator matrix data, and system geometry including pulse tube, regenerator size and operating frequency for pulse tube cryocooler. The model investigates the effect of orifice opening, double inlet opening, pressure ratio, system geometry on no load temperature and refrigeration power at various temperatures for different charging pressure. The results are compared with experimental data and reasonable agreement is observed. The model can further be extended for designing two stage pulse tube cryocooler.

  11. Loss Analysis of High Power Stirling-Type Pulse Tube Cryocooler

    Science.gov (United States)

    Nakano, K.; Hiratsuka, Y.

    2015-12-01

    For the purpose of cooling high-temperature superconductor (HTS) devices, such as superconductor motors, superconducting magnetic energy storage (SMES) and current fault limiters, cryocoolers should be compact in size, light-weight, and have high efficiency and reliability. In order to meet the demand of HTS devices world-wide, the cryocooler needs to have COP efficiency >0.1. We have developed a high power Stirling-type pulse tube cryocooler (SPTC) with an in-line expander. The experimental results were reported in June 2012[1]. The cooling capacity was 210 W at 77 K and the minimum temperature was 37 K when the compressor input power was 3.8 kW. Accordingly, the COP was about 0.055. To further improve the efficiency, the energy losses in the cryocooler were analyzed. The experimental results and the numerical calculation results are reported in this paper.

  12. Miniature Stirling cryocoolers at Thales Cryogenics: qualification results and integration solutions

    Science.gov (United States)

    Arts, R.; Martin, J.-Y.; Willems, D.; Seguineau, C.; de Jonge, G.; Van Acker, S.; Mullié, J.; Le Bordays, J.; Benschop, T.

    2016-05-01

    During the 2015 SPIE-DSS conference, Thales Cryogenics presented new miniature cryocoolers for high operating temperatures. In this paper, an update is given regarding the qualification programme performed on these new products. Integration aspects are discussed, including an in-depth examination of the influence of the dewar cold finger on sizing and performance of the cryocooler. The UP8197 will be placed in the reference frame of the Thales product range of high-reliability linear cryocoolers, while the rotary solution will be considered as the most compact solution in the Thales portfolio. Compatibility of the cryocoolers design with new and existing 1/4" dewar designs is examined, and potential future developments are presented.

  13. 4 Kelvin Cooling with Innovative Final Stage of Multistage Cryocooler Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Proposed for development is a proof-of-concept prototype for the final stage of a multistage cryocooler. This final stage comprises a high frequency pulse tube cold...

  14. Development of miniature moving magnet cryocooler SX040

    Science.gov (United States)

    Rühlich, I.; Mai, M.; Rosenhagen, C.; Schreiter, A.; Möhl, C.

    2011-06-01

    State of the art high performance cooled IR systems need to have more than just excellent E/O performance. Minimum size weight and power (SWaP) are the design goals to meet our forces' mission requirements. Key enabler for minimum SWaP of IR imagers is the operation temperature of the focal plane array (FPA) employed. State of the art MCT or InAsSb nBn technology has the potential to rise the FPA temperature from 77 K to 130-150 K (high operation temperature HOT) depending on the specific cut-off wavelength. Using a HOT FPA will significantly lower SWaP and keep those parameters finally dominated by the employed cryocooler. Therefore compact high performance cryocoolers are mandatory. For highest MTTF life AIM developed its Flexure Bearing Moving Magnet product family "SF". Such coolers achieve more than 20000 h MTTF with Stirling type expander and more than 5 years MTTF life with Pulse Tube coldfinger (like for Space applications). To keep the high lifetime potential but to significantly improve SWaP AIM is developing its "SX" type cooler family. The new SX040 cooler incorporates a highly efficient dual piston Moving Magnet driving mechanism resulting in very compact compressor of less than 100mm length. The cooler's high lifetime is also achieved by placing the coils outside the helium vessel as usual for moving magnet motors. The mating ¼" expander is extremely compact with less than 63 mm length. This allows a total dewar length from optical window to expander warm end of less than 100 mm even for large cold shields. The cooler is optimized for HOT detectors with operating temperatures exceeding 95 K. While this kind of cooler is the perfect match for many applications, handheld sights or targeting devices for the dismounted soldier are even more challenging with respect to SWaP. AIM therefore started to develop an even smaller cooler type with single piston and balancer. This paper gives an overview on the development of this new compact cryocooler. Technical

  15. Thin-film metal hydrides.

    Science.gov (United States)

    Remhof, Arndt; Borgschulte, Andreas

    2008-12-01

    The goal of the medieval alchemist, the chemical transformation of common metals into nobel metals, will forever be a dream. However, key characteristics of metals, such as their electronic band structure and, consequently, their electric, magnetic and optical properties, can be tailored by controlled hydrogen doping. Due to their morphology and well-defined geometry with flat, coplanar surfaces/interfaces, novel phenomena may be observed in thin films. Prominent examples are the eye-catching hydrogen switchable mirror effect, the visualization of solid-state diffusion and the formation of complex surface morphologies. Thin films do not suffer as much from embrittlement and/or decrepitation as bulk materials, allowing the study of cyclic absorption and desorption. Therefore, thin-metal hydride films are used as model systems to study metal-insulator transitions, for high throughput combinatorial research or they may be used as indicator layers to study hydrogen diffusion. They can be found in technological applications as hydrogen sensors, in electrochromic and thermochromic devices. In this review, we discuss the effect of hydrogen loading of thin niobium and yttrium films as archetypical examples of a transition metal and a rare earth metal, respectively. Our focus thereby lies on the hydrogen induced changes of the electronic structure and the morphology of the thin films, their optical properties, the visualization and the control of hydrogen diffusion and on the study of surface phenomena and catalysis.

  16. Technical and economic evaluation of hydrogen storage systems based on light metal hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Jepsen, Julian

    2014-07-01

    Novel developments regarding materials for solid-state hydrogen storage show promising prospects. These complex hydrides exhibit high mass-related storage capacities and thus great technical potential to store hydrogen in an efficient and safe way. However, a comprehensive evaluation of economic competitiveness is still lacking, especially in the case of the LiBH4 / MgH2 storage material. In this study, an assessment with respect to the economic feasibility of implementing complex hydrides as hydrogen storage materials is presented. The cost structure of hydrogen storage systems based on NaAlH4 and LiBH4 / MgH2 is discussed and compared with the conventional high pressure (700 bar) and liquid storage systems. Furthermore, the properties of LiBH4 / MgH2, so-called Li-RHC (Reactive Hydride Composite), are scientifically compared and evaluated on the lab and pilot plant scale. To enhance the reaction rate, the addition of TiCl3 is investigated and high energy ball milling is evaluated as processing technique. The effect of the additive in combination with the processing technique is described in detail. Finally, an optimum set of processing parameters and additive content are identified and can be applied for scaled-up production of the material based on simple models considering energy input during processing. Furthermore, thermodynamic, heat transfer and kinetic properties are experimentally determined by different techniques and analysed as a basis for modelling and designing scaled-up storage systems. The results are analysed and discussed with respect to the reaction mechanisms and reversibility of the system. Heat transfer properties are assessed with respect to the scale-up for larger hydrogen storage systems. Further improvements of the heat transfer were achieved by compacting the material. In this regard, the influence of the compaction pressure on the apparent density, thermal conductivity and sorption behaviour, was investigated in detail. Finally, scaled

  17. Development of a dry linear compressor for GM and pulse tube cryocoolers

    CERN Document Server

    Höhne, Jens

    2015-01-01

    Pressure Wave Systems GmbH has developed a dry compressor for GM and pulse tube cryocoolers. The concept is based on hydraulically driven metal bellows in which the Helium working gas is compressed. The system is operated in the region of 1 kW of electrical input power and has been successfully tested with a SHI RDK-101D GM cryocooler cold head. Set-up, performance and reliability of the compressor system will be discussed.

  18. Development of a dry linear compressor for GM and pulse tube cryocoolers

    Science.gov (United States)

    Hoehne, J.

    2015-12-01

    Pressure Wave Systems GmbH has developed a dry compressor for GM and pulse tube cryocoolers. The concept is based on hydraulically driven metal bellows in which the Helium working gas is compressed. The system is operated in the region of 1 kW of electrical input power and has been successfully tested with a SHI RDK-101D GM cryocooler cold head. Set-up, performance and reliability of the compressor system will be discussed.

  19. Physical and Structural Studies on the Cryo-cooling of Insulin Crystals

    Science.gov (United States)

    Lovelace, J.; Bellamy, H.; Snell, E. H.; Borgstahl, G.

    2003-01-01

    Reflection profiles were analyzed from microgravity-(mg) and earth-grown insulin crystals to measure mosaicity (h) and to reveal mosaic domain structure and composition. The effects of cryocooling on single and multi-domain crystals were compared. The effects of cryocooling on insulin structure were also re-examined. Microgravity crystals were larger, more homogeneous, and more perfect than earth crystals. Several mg crystals contained primarily a single mosaic domain with havg of 0.005deg. The earth crystals varied in quality and all contained multiple domains with havg of 0.031deg. Cryocooling caused a 43-fold increase in h for mg crystals (havg=0.217deg) and an %fold increase for earth crystals (havg=0.246deg). These results indicate that very well-ordered crystals are not completely protected from the stresses associated with cryocooling, especially when structural perturbations occur. However, there were differences in the reflection profiles. For multi-mosaic domain crystals, each domain individually broadened and separated from the other domains upon cryo-cooling. Cryo-cooling did not cause an increase in the number of domains. A crystal composed of a single domain retained this domain structure and the reflection profiles simply broadened. Therefore, an improved signal-to-noise ratio for each reflection was measured from cryo-cooled single domain crystals relative to cryo-cooled multi-domain crystals. This improved signal, along with the increase in crystal size, facilitated the measurement of the weaker high- resolution reflections. The observed broadening of reflection profiles indicates increased variation in unit cell dimensions which may be linked to cryo-cooling-associated structural changes and disorder.

  20. High H- ionic conductivity in barium hydride

    Science.gov (United States)

    Verbraeken, Maarten C.; Cheung, Chaksum; Suard, Emmanuelle; Irvine, John T. S.

    2015-01-01

    With hydrogen being seen as a key renewable energy vector, the search for materials exhibiting fast hydrogen transport becomes ever more important. Not only do hydrogen storage materials require high mobility of hydrogen in the solid state, but the efficiency of electrochemical devices is also largely determined by fast ionic transport. Although the heavy alkaline-earth hydrides are of limited interest for their hydrogen storage potential, owing to low gravimetric densities, their ionic nature may prove useful in new electrochemical applications, especially as an ionically conducting electrolyte material. Here we show that barium hydride shows fast pure ionic transport of hydride ions (H-) in the high-temperature, high-symmetry phase. Although some conductivity studies have been reported on related materials previously, the nature of the charge carriers has not been determined. BaH2 gives rise to hydride ion conductivity of 0.2 S cm-1 at 630 °C. This is an order of magnitude larger than that of state-of-the-art proton-conducting perovskites or oxide ion conductors at this temperature. These results suggest that the alkaline-earth hydrides form an important new family of materials, with potential use in a number of applications, such as separation membranes, electrochemical reactors and so on.

  1. Sorption phenomena of PCBs in environment

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The relationship between the properties of PCBs and the behavior of soil and sediment is reviewed. The sorption phenomena of PCBs in the environment are described with different models. The research progress on the sorption mechanisms is also discussed.

  2. Development of a Space-Type 4-Stage Pulse Tube Cryocooler for Very Low Temperature

    Science.gov (United States)

    Olson, J. R.; Moore, M.; Champagne, P.; Roth, E.; Evtimov, B.; Jensen, J.; Collaço, A.; Nast, T.

    2006-04-01

    The Lockheed Martin Advanced Technology Center (LMATC) has built and tested a 4-stage pulse tube cryocooler, which provides simultaneous cooling at 6 K and 18 K. The cryocooler is designed to meet NASA's cryocooler needs for low temperature, with immediate application to the Terrestrial Planet Finder, Constellation-X, and other future space-science missions. The simplicity with LMATC's approach of the single compressor, coldhead, and electronic controller makes it very appealing for applications requiring high reliability. It further allows the system to be readily modified for different program requirements. The LM pulse tube is a simple 4-stage coldhead with no moving parts, driven by a long-life linear flexure-bearing clearance-seal compressor. The cryocooler is designed to provide 20 mW of cooling at 6 K and 150 mW cooling at 18 K while rejecting heat at 290 K. Performance data is presented, showing excellent cryocooler performance, meeting JPL's cooling requirements, and achieving a no-load temperature below 4 K. This work was funded by the Jet Propulsion Laboratory's Advanced Cryocooler Technology Development Program (ACTDP), Ron G. Ross, Contract Manager.

  3. Spinal cord evoked magnetic field measurement using a magnetospinography system equipped with a cryocooler.

    Science.gov (United States)

    Adachi, Yoshiaki; Oyama, Daisuke; Kawai, Jun; Kawabata, Shigenori; Uehara, Gen

    2013-01-01

    We have developed a magnetospinography (MSG) system that detects weak magnetic fields associated with spinal cord neural activity using an array of low-temperature superconducting quantum interference device (SQUID)-based magnetic flux sensors. A functional image of the spinal cord can be obtained noninvasively by using this system, and it is effective for precise lesion localization in the diagnosis of spinal cord diseases. The running cost of the developed MSG system mainly depends on liquid helium (LHe) consumption, which is required to maintain the superconducting state of the SQUID sensors. To reduce the LHe consumption, we incorporate a pulse-tube-refrigerator-based cryocooler into the MSG system. Cold gaseous helium is circulated between the cryocooler and the MSG system for cooling the thermal radiation shield of the dewar vessel. Consequently, we achieved a 46% decrease in the LHe consumption rate. Conventional biomagnetic field detection such as magnetoencephalography is often hindered by severe low-frequency band noise from the cryocooler. However, in the case of MSG measurements, such noise can be filtered out because the band of the signal is much higher than that of the cryocooler noise. We demonstrated that the signal-to-noise ratio of the cervical spinal cord evoked magnetic field measurement performed with a working cryocooler is comparable to that of the measurement without a cryocooler.

  4. Optimization of a Brayton cryocooler for ZBO liquid hydrogen storage in space

    Science.gov (United States)

    Deserranno, D.; Zagarola, M.; Li, X.; Mustafi, S.

    2014-11-01

    NASA is evaluating and developing technology for long-term storage of cryogenic propellant in space. A key technology is a cryogenic refrigerator which intercepts heat loads to the storage tank, resulting in a reduced- or zero-boil-off condition. Turbo-Brayton cryocoolers are particularly well suited for cryogen storage applications because the technology scales well to high capacities and low temperatures. In addition, the continuous-flow nature of the cycle allows direct cooling of the cryogen storage tank without mass and power penalties associated with a cryogenic heat transport system. To quantify the benefits and mature the cryocooler technology, Creare Inc. performed a design study and technology demonstration effort for NASA on a 20 W, 20 K cryocooler for liquid hydrogen storage. During the design study, we optimized these key components: three centrifugal compressors, a modular high-capacity plate-fin recuperator, and a single-stage turboalternator. The optimization of the compressors and turboalternator were supported by component testing. The optimized cryocooler has an overall flight mass of 88 kg and a specific power of 61 W/W. The coefficient of performance of the cryocooler is 23% of the Carnot cycle. This is significantly better performance than any 20 K space cryocooler existing or under development.

  5. Extended range of the Lockheed Martin coax Micro cryocooler

    Science.gov (United States)

    Frank, D.; Champagne, P.; Will, E.; Kaldas, G.; Sanders, L.; Roth, E.; Olson, J. R.

    2016-03-01

    This paper describes the higher cooling capability of the Lockheed Martin coax Micro cryocooler thermal mechanical unit. The design of the previously qualified TRL6 Micro (Nast et al., 2014) [1] was modified to accommodate over twice the input power, greatly increasing the cooling capability. These Micro units are in a split configuration with the cold head separated from the compressor. This unit was optimized for cooling at 105 K and provides cooling over a wide range of temperatures. With a weight below 450 g, this small unit is ideal for compact instruments. Load lines were obtained over a range of powers, cold tip temperatures and rejection temperatures. This testing raised the Technology Readiness Level to six.

  6. A helium liquefier using three 4 k pulse tube cryocoolers

    Science.gov (United States)

    Wang, Chao; Oviedo, Abner

    2012-06-01

    We have developed a helium liquefier which can be used for recondensing/reliquefying helium vapor in a helium cryostat or liquefying helium gas in a storage dewar. The helium liquefier employs three 4 K pulse tube cryocoolers, Cryomech model PT415. Each PT415 has remote motor/rotary valve assembly to minimize vibration, providing ≥ 1.5W at 4.2K. The liquefier can liquefy room temperature helium gas with a liquefaction rate of 62 Liter/day. When installing it in the cryostat, it can recondense and reliquefy helium vapor with a rate of 78 L/day. The liquefier will be installed in a gravitational wave detector in Brazil to recondense/reliquefy the helium boil off from the cryostat.

  7. Application of Cryocoolers to a Vintage Dilution Refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, Richard; Smith, Gary; Ruschman, Mark; /Fermilab; Beaty, Jim; /Minnesota U.

    2011-06-06

    A dilution refrigerator is required for 50mK detector operation of CDMS (Cryogenic Dark Matter Search). Besides shielding the dilution refrigerator itself, the liquid nitrogen shield and liquid helium bath in the refrigerator cool the detector cryostat heat shields and cool electronics, resulting in significant external heat loads at 80K and at 4K. An Oxford Instruments Kelvinox 400 has served this role for ten years but required daily transfers of liquid nitrogen and liquid helium. Complicating the cryogen supply is the location 800 meters below ground in an RF shielded, class 10000 clean room at Soudan, MN. Nitrogen and helium re-liquefiers using cryocoolers were installed outside the clean room and continuously condense room temperature gas and return the liquids to the dilution refrigerator through a transfer line. This paper will describe the design, installation, controls and performance of liquefaction systems.

  8. Application of cryocoolers to a vintage dilution refrigerator

    Science.gov (United States)

    Schmitt, Richard L.; Smith, Gary; Ruschman, Mark; Beaty, Jim

    2012-06-01

    A dilution refrigerator is required for 50 mK detector operation of CDMS (Cryogenic Dark Matter Search). Besides shielding the dilution refrigerator itself, the liquid nitrogen shield and liquid helium bath in the refrigerator cool the detector cryostat heat shields and cool electronics, resulting in significant external heat loads at 80 K and at 4 K. An Oxford Instruments Kelvinox 400 has served this role for ten years but required daily transfers of liquid nitrogen and liquid helium. Complicating the cryogen supply is the location 800 meters below ground in an RF shielded, class 10000 clean room at Soudan, MN. Nitrogen and helium re-liquefiers using cryocoolers were installed outside the clean room and continuously condense room temperature gas and return the liquids to the dilution refrigerator through a transfer line. This paper will describe the design, installation, controls and performance of liquefaction systems.

  9. Vibration-free stirling cryocooler for high definition microscopy

    Science.gov (United States)

    Riabzev, S. V.; Veprik, A. M.; Vilenchik, H. S.; Pundak, N.; Castiel, E.

    2009-12-01

    The normal operation of high definition Scanning Electronic and Helium Ion microscope tools often relies on maintaining particular components at cryogenic temperatures. This has traditionally been accomplished by using liquid coolants such as liquid Nitrogen. This inherently limits the useful temperature range to above 77 K, produces various operational hazards and typically involves elevated ownership costs, inconvenient logistics and maintenance. Mechanical coolers, over-performing the above traditional method and capable of delivering required (even below 77 K) cooling to the above cooled components, have been well-known elsewhere for many years, but their typical drawbacks, such as high purchasing cost, cooler size, low reliability and high power consumption have so far prevented their wide-spreading. Additional critical drawback is inevitable degradation of imagery performance originated from the wideband vibration export as typical for the operation of the mechanical cooler incorporating numerous movable components. Recent advances in the development of reliable, compact, reasonably priced and dynamically quiet linear cryogenic coolers gave rise to so-called "dry cooling" technologies aimed at eventually replacing the traditional use of outdated liquid Nitrogen cooling facilities. Although much improved these newer cryogenic coolers still produce relatively high vibration export which makes them incompatible with modern high definition microscopy tools. This has motivated further research activity towards developing a vibration free closed-cycle mechanical cryocooler. The authors have successfully adapted the standard low vibration Stirling cryogenic refrigerator (Ricor model K535-LV) delivering 5 W@40 K heat lift for use in vibration-sensitive high definition microscopy. This has been achieved by using passive mechanical counterbalancing of the main portion of the low frequency vibration export in combination with an active feed-forward multi

  10. The Ricor K508 cryocooler operational experience on Mars

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Dean L.; Lysek, Mark J.; Morookian, John Michael [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2014-01-29

    The Mars Science Laboratory (Curiosity) landed successfully on Mars on August 5, 2012, eight months after launch. The chosen landing site of Gale Crater, located at 4.5 degrees south latitude, 137.4 degrees east longitude, has provided a much more benign environment than was originally planned for during the critical design and integration phases of the MSL Project when all possible landing sites were still being considered. The expected near-surface atmospheric temperatures at the Gale Crater landing site during Curiosity's primary mission (1 Martian year or 687 Earth days) are from −90°C to 0°C. However, enclosed within Curiosity's thermal control fluid loops the Chemistry and Mineralogy (CheMin) instrument is maintained at approximately +20°C. The CheMin instrument uses X-ray diffraction spectroscopy to make precise measurements of mineral constituents of Mars rocks and soil. The instrument incorporated the commercially available Ricor K508 Stirling cycle cryocooler to cool the CCD detector. After several months of brushing itself off, stretching and testing out its subsystems, Curiosity began the exploration of the Mars surface in October 2012. The CheMin instrument on the Mars Science Laboratory (MSL) received its first soil sample from Curiosity on October 24, and successfully analyzed its first soil sample. After a brief review of the rigorous Ricor K508 cooler qualification tests and life tests based on the original MSL environmental requirements this paper presents final pre-launch instrument integration and testing results, and details the operational data of the CheMin cryocooler, providing a snapshot of the resulting CheMin instrument analytical data.

  11. Lattice contraction in photochromic yttrium hydride

    Energy Technology Data Exchange (ETDEWEB)

    Maehlen, Jan Petter, E-mail: jepe@ife.no; Mongstad, Trygve T.; You, Chang Chuan; Karazhanov, Smagul

    2013-12-15

    Highlights: •Photochromic yttrium hydride films (YH:O) were prepared by reactive sputtering. •Black and transparent YH:O films were studied by time-resolved synchrotron XRD. •Both YH:O samples showed a lattice contraction upon illumination. •Also exposure to the X-ray beam itself results in a lattice contraction. -- Abstract: A strong photochromic effect was recently discovered in thin films of oxygen-containing yttrium hydride taking place at room temperature and reacting to ultraviolet and visible light. In this paper, we report on a lattice contraction upon illumination observed for thin-film samples of photochromic yttrium hydride, recorded by time-resolved X-ray diffraction using synchrotron radiation. The time dependence of the lattice contraction is consistent with the observed photochromic response of the samples.

  12. Atom probe analysis of titanium hydride precipitates.

    Science.gov (United States)

    Takahashi, J; Kawakami, K; Otsuka, H; Fujii, H

    2009-04-01

    It is expected that the three-dimensional atom probe (3DAP) will be used as a tool to visualize the atomic scale of hydrogen atoms in steel is expected, due to its high spatial resolution and very low detection limit. In this paper, the first 3DAP analysis of titanium hydride precipitates in metal titanium is reported in terms of the quantitative detection of hydrogen. FIB fabrication techniques using the lift-out method have enabled the production of needle tips of hydride precipitates, of several tens of microns in size, within a titanium matrix. The hydrogen concentration estimated from 3DAP analysis was slightly smaller than that of the hydride phase predicted from the phase diagram. We discuss the origin of the difference between the experimental and predicted values and the performance of 3DAP for the quantitative detection of hydrogen.

  13. Hydrogen storage in complex metal hydrides

    Directory of Open Access Journals (Sweden)

    BORISLAV BOGDANOVIĆ

    2009-02-01

    Full Text Available Complex metal hydrides such as sodium aluminohydride (NaAlH4 and sodium borohydride (NaBH4 are solid-state hydrogen-storage materials with high hydrogen capacities. They can be used in combination with fuel cells as a hydrogen source thus enabling longer operation times compared with classical metal hydrides. The most important point for a wide application of these materials is the reversibility under moderate technical conditions. At present, only NaAlH4 has favourable thermodynamic properties and can be employed as a thermally reversible means of hydrogen storage. By contrast, NaBH4 is a typical non- -reversible complex metal hydride; it reacts with water to produce hydrogen.

  14. Iron Group Hydrides in Noyori Bifunctional Catalysis.

    Science.gov (United States)

    Morris, Robert H

    2016-12-01

    This is an overview of the hydride-containing catalysts prepared in the Morris group for the efficient hydrogenation of simple ketones, imines, nitriles and esters and the asymmetric hydrogenation and transfer hydrogenation of prochiral ketones and imines. The work was inspired by and makes use of Noyori metal-ligand bifunctional concepts involving the hydride-ruthenium amine-hydrogen HRuNH design. It describes the synthesis and some catalytic properties of hydridochloro, dihydride and amide complexes of ruthenium and in one case, osmium, with monodentate, bidentate and tetradentate phosphorus and nitrogen donor ligands. The iron hydride that has been identified in a very effective asymmetric transfer hydrogenation process is also mentioned. The link between the HMNH structure and the sense of enantioinduction is demonstrated by use of simple transition state models.

  15. Thermodynamic analysis of a thermally operated cascade sorption heat pump for continuous cold generation

    Directory of Open Access Journals (Sweden)

    P. Muthukumar, D.V.N. Lakshmi

    2013-01-01

    Full Text Available In this paper, the thermodynamic analysis of a cascade sorption system consists of a two-stage metal hydride heat pump as topping cycle and a single-stage lithium bromide water system as bottom cycle is presented. The effects of various operating temperatures such as driving heat, heat release and refrigeration temperatures, and design parameters such as ratio of metal hydride mass to reactor mass and sensible heat exchange factor on the combined coefficient of performance (COP of the cascade cycle, and specific cooling power (SCP and total cold output of the metal hydride heat pump cycle are presented. It is observed that the combined COP is found to increase with heat release and refrigeration temperatures and however, decreases with driving heat temperature. Increase of sensible heat exchange factor improves the system performances significantly. Reduction in mass ratio from 0.5 to 0.1 improves the combined COP of the cascade system by about 10 %. The maximum predicted combined COP of the system is about 1.66 at the driving heat, heat release and refrigeration temperatures of 270 °C, 125 °C and 12°C, respectively.

  16. Thermodynamic analysis of a thermally operated cascade sorption heat pump for continuous cold generation

    Energy Technology Data Exchange (ETDEWEB)

    Muthukumar, P.; Lakshmi, D.V.N. [Department of Mechanical Engineering, Indian Institute of Technology, Guwahati – 781039 (India)

    2013-07-01

    In this paper, the thermodynamic analysis of a cascade sorption system consists of a two-stage metal hydride heat pump as topping cycle and a single-stage lithium bromide water system as bottom cycle is presented. The effects of various operating temperatures such as driving heat, heat release and refrigeration temperatures, and design parameters such as ratio of metal hydride mass to reactor mass and sensible heat exchange factor on the combined coefficient of performance (COP) of the cascade cycle, and specific cooling power (SCP) and total cold output of the metal hydride heat pump cycle are presented. It is observed that the combined COP is found to increase with heat release and refrigeration temperatures and however, decreases with driving heat temperature. Increase of sensible heat exchange factor improves the system performances significantly. Reduction in mass ratio from 0.5 to 0.1 improves the combined COP of the cascade system by about 10 %. The maximum predicted combined COP of the system is about 1.66 at the driving heat, heat release and refrigeration temperatures of 270 deg C, 125 deg C and 12deg C, respectively.

  17. Moisture Sorption in Porous Materials

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    2007-01-01

    Abstract: Information on pore geometry is very important in any study of the mechanical and physical behavior of porous materials. Unfortunately pores are not very accessible for direct measurements. Indirect methods have to be used which involve impregnation (sorption) experiments from which...... in the subject considered this software is available on request to the author. Keywords: Porous materials, moisture, adsorption, desorption, BET-parameters....

  18. Oil sorption by lignocellulosic fibers

    Science.gov (United States)

    Beom-Goo. Lee; James S. Han; Roger M. Rowell

    1999-01-01

    The oil sorption capacities of cotton fiber, kenaf bast fiber, kenaf core fiber, and moss fiber were compared after refining, extraction, and reduction in particle sizes. The tests were conducted on diesel oil in a pure form. Cotton fiber showed the highest capacity, followed by kenaf core and bast fibers. Wetting, extraction, and reduction in particle size all...

  19. Evidence of stress-induced hydrogen ordering in zirconium hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Steuwer, A. [FaME38 at the ESRF-ILL, 6 rue J Horowitz, 38042 Grenoble (France); ESS Scandinavia, University of Lund, Stora Algatan 4, 22350 Lund (Sweden)], E-mail: steuwer@ill.fr; Santisteban, J.R. [Centro Atomico Bariloche, CNEA, San Carlos de Bariloche (Argentina); Preuss, M. [University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Peel, M.J.; Buslaps, T. [European Synchrotron Radiation Facility, 6 rue J Horowitz, 38042 Grenoble (France); Harada, M. [R and D Section, Chofu-Kita Plant, Kobe Special Tube Co, Shimonoseki 752-0953 (Japan)

    2009-01-15

    The formation of hydrides in zirconium alloys significantly affects their mechanical properties and is considered to play a critical role in their failure mechanisms, yet relatively little is known about the micromechanical behavior of hydrides in the bulk. This paper presents the result of in situ uniaxial mechanical tensioning experiments on hydrided zircaloy-2 and zircaloy-4 specimens using energy-dispersive synchrotron X-ray diffraction, which suggests that a stress-induced transformation of the {delta}-hydride to {gamma}-hydride via ordering of the hydrogen atoms occurs, akin to a Snoek-type relaxation. Subsequent annealing was found to reverse the ordering phenomenon.

  20. A magnetic resonance (MR) microscopy system using a microfluidically cryo-cooled planar coil.

    Science.gov (United States)

    Koo, Chiwan; Godley, Richard F; Park, Jaewon; McDougall, Mary P; Wright, Steven M; Han, Arum

    2011-07-07

    We present the development of a microfluidically cryo-cooled planar coil for magnetic resonance (MR) microscopy. Cryogenically cooling radiofrequency (RF) coils for magnetic resonance imaging (MRI) can improve the signal to noise ratio (SNR) of the experiment. Conventional cryostats typically use a vacuum gap to keep samples to be imaged, especially biological samples, at or near room temperature during cryo-cooling. This limits how close a cryo-cooled coil can be placed to the sample. At the same time, a small coil-to-sample distance significantly improves the MR imaging capability due to the limited imaging depth of planar MR microcoils. These two conflicting requirements pose challenges to the use of cryo-cooling in MR microcoils. The use of a microfluidic based cryostat for localized cryo-cooling of MR microcoils is a step towards eliminating these constraints. The system presented here consists of planar receive-only coils with integrated cryo-cooling microfluidic channels underneath, and an imaging surface on top of the planar coils separated by a thin nitrogen gas gap. Polymer microfluidic channel structures fabricated through soft lithography processes were used to flow liquid nitrogen under the coils in order to cryo-cool the planar coils to liquid nitrogen temperature (-196 °C). Two unique features of the cryo-cooling system minimize the distance between the coil and the sample: (1) the small dimension of the polymer microfluidic channel enables localized cooling of the planar coils, while minimizing thermal effects on the nearby imaging surface. (2) The imaging surface is separated from the cryo-cooled planar coil by a thin gap through which nitrogen gas flows to thermally insulate the imaging surface, keeping it above 0 °C and preventing potential damage to biological samples. The localized cooling effect was validated by simulations, bench testing, and MR imaging experiments. Using this cryo-cooled planar coil system inside a 4.7 Tesla MR system

  1. Atoms and Nanoparticles of Transition Metals as Catalysts for Hydrogen Desorption from Magnesium Hydride

    Directory of Open Access Journals (Sweden)

    N. Bazzanella

    2011-01-01

    Full Text Available The hydrogen desorption kinetics of composite materials made of magnesium hydride with transition metal additives (TM: Nb, Fe, and Zr was studied by several experimental techniques showing that (i a few TM at.% concentrations catalyse the H2 desorption process, (ii the H2 desorption kinetics results stabilized after a few H2 sorption cycles when TM atoms aggregate by forming nanoclusters; (iii the catalytic process occurs also at TM concentration as low as 0.06 at.% when TM atoms clustering is negligible, and (iv mixed Fe and Zr additives produce faster H2 desorption kinetics than single additive. The improved H2 desorption kinetics of the composite materials can be explained by assuming that the interfaces between the MgH2 matrix and the TM nanoclusters act as heterogeneous sites for the nucleation of the Mg phase in the MgH2 matrix and promote the formation of fast diffusion channels for H migrating atoms.

  2. Hydride formation on deformation twin in zirconium alloy

    Science.gov (United States)

    Kim, Ju-Seong; Kim, Sung-Dae; Yoon, Jonghun

    2016-12-01

    Hydrides deteriorate the mechanical properties of zirconium (Zr) alloys used in nuclear reactors. Intergranular hydrides that form along grain boundaries have been extensively studied due to their detrimental effects on cracking. However, it has been little concerns on formation of Zr hydrides correlated with deformation twins which is distinctive heterogeneous nucleation site in hexagonal close-packed metals. In this paper, the heterogeneous precipitation of Zr hydrides at the twin boundaries was visualized using transmission electron microscopy. It demonstrates that intragranular hydrides in the twinned region precipitates on the rotated habit plane by the twinning and intergranular hydrides precipitate along the coherent low energy twin boundaries independent of the conventional habit planes. Interestingly, dislocations around the twin boundaries play a substantial role in the nucleation of Zr hydrides by reducing the misfit strain energy.

  3. Nucleation and growth mechanisms of nano magnesium hydride from the hydrogen sorption kinetics.

    Science.gov (United States)

    Mooij, Lennard; Dam, Bernard

    2013-07-21

    We use a combination of hydrogenography and Johnson-Mehl-Avrami-Kolmogorov (JMAK) analyses to identify (1) the driving force dependence of the nucleation and growth mechanism of MgH2 in thin film multilayers of Mg (10 nm) and (2) the nucleation and growth mechanism of Mg in the earlier formed MgH2, i.e. the hydrogen desorption process. We conclude that JMAK may be successfully applied to obtain the nucleation and growth mechanism of hydrogen absorption. The desorption mechanism, however, is not simply the reverse of the absorption mechanism. We find evidence that the barrier for nucleation of Mg is small. The dehydrogenation probably involves the formation of voids, which is energetically more favorable than elastic and plastic deformation of the multilayer.

  4. Destabilization of magnesium hydride through interface engineering

    NARCIS (Netherlands)

    Mooij, L.P.A.

    2013-01-01

    The aim of this thesis is to study the thermodynamics of hydrogenation of nanoconfined magnesium within a thin film multilayer model system. Magnesium hydride is a potential material for hydrogen storage, which is a key component in a renewable energy system based on hydrogen. In bulk form,

  5. Destabilization of magnesium hydride through interface engineering

    NARCIS (Netherlands)

    Mooij, L.P.A.

    2013-01-01

    The aim of this thesis is to study the thermodynamics of hydrogenation of nanoconfined magnesium within a thin film multilayer model system. Magnesium hydride is a potential material for hydrogen storage, which is a key component in a renewable energy system based on hydrogen. In bulk form, magnesiu

  6. Destabilization of magnesium hydride through interface engineering

    NARCIS (Netherlands)

    Mooij, L.P.A.

    2013-01-01

    The aim of this thesis is to study the thermodynamics of hydrogenation of nanoconfined magnesium within a thin film multilayer model system. Magnesium hydride is a potential material for hydrogen storage, which is a key component in a renewable energy system based on hydrogen. In bulk form, magnesiu

  7. Aging Effects on the Hydrogen Storage Characteristics of Li-Mg-B-N-H Complex Hydrides

    Science.gov (United States)

    Srinivasan, Sesha; Vickers, Eric; Mulharan, James; Darkazalli, Gazi; Goswami, Yogi; Stefanakos, Elias; FLPoly-CERC Collaboration

    2015-03-01

    The aging effects on the hydrogen storage characteristics and chemical formulations of the complex hydrides are discussed in this study. The aging effects due to atmospheric events such as oxygen and moisture coverage and self-decomposition are currently under investigation. The candidate material chosen for this study is Lithium/Magnesium based complex hydride LiBH4/LiNH2/MgH2. These materials were prepared using high energy ball milling under Ar/H2 atmosphere with different milling durations. The chemical, structural and microstructural characteristics of the synthesized and aged materials were compared and investigated using TGA/DSC, FTIR, XRD, BET and SEM analytical tools. Hydrogen storage properties such as hydrogen sorption kinetics, cycle life and pressure-composition isotherm (PCI) was examined via high pressure, high temperature Sievert's type apparatus. This current study will shed light to compare and contrast the above mentioned characteristics for the aged samples practically at the same experimental conditions. Furthermore, we have investigated the relationship between the aging effects with respect to the crystallite sizes of the candidate compounds and their nano-dopant variants. We acknowledge the grant from Florida Energy Systems Consortium and support from Florida Polytechnic University.

  8. Advances on a cryogen-free Vuilleumier type pulse tube cryocooler

    Science.gov (United States)

    Wang, Yanan; Zhao, Yuejing; Zhang, Yibing; Wang, Xiaotao; Vanapalli, Srinivas; Dai, Wei; Li, Haibing; Luo, Ercang

    2017-03-01

    This paper presents experimental results and numerical evaluation of a Vuilleumier (VM) type pulse tube cryocooler. The cryocooler consists of three main subsystems: a thermal compressor, a low temperature pulse tube cryocooler, and a Stirling type precooler. The thermal compressor, similar to that in a Vuilleumier cryocooler, is used to drive the low temperature stage pulse tube cryocooler. The Stirling type precooler is used to establish a temperature difference for the thermal compressor to generate pressure wave. A lowest no-load temperature of 15.1 K is obtained with a pressure ratio of 1.18, a working frequency of 3 Hz and an average pressure of 2.45 MPa. Numerical simulations have been performed to help the understanding of the system performance. With given experimental conditions, the simulation predicts a lowest temperature in reasonable agreement with the experimental result. Analyses show that there is a large discrepancy in the pre-cooling power between experiments and calculation, which requires further investigation.

  9. RICOR Cryocoolers for HOT IR detectors from development to optimization for industrialized production

    Science.gov (United States)

    Levin, Eli; Katz, Amiram; Bar Haim, Zvi; Nachman, Ilan; Riabzev, Sergey; Gover, Dan; Segal, Victor; Filis, Avishai

    2017-05-01

    The modern needs of the electro-optical market for small low-power and light-weight IR systems are impelling research and development of High Operating Temperature (HOT) IR detectors, requiring development of dedicated "HOT" cryocoolers. The development of cryocoolers with emphasis on the "SWAP3" configuration means small size, low weight, improved performance, low power consumption and low price, in order to optimize IDDCA for future hand held thermal sights. This paper will present the development and the progress made with the new "HOT" cryocooler, including customer data after the evaluation process, performances achieved using a common cold finger, test results update on a large series of production coolers, life and qualification test update and acoustic noise reduction. All the above mentioned information relates to the FPA temperature range of 130 - 200K for various cryocooler models based on rotary and linear design concepts. The paper will also review the progress with the latest development activities implemented in the cryocoolers and the electronic control modules in order to improve reliability and minimize regulated power consumption.

  10. Integration of a Cryocooler into a SQUID Magnetospinography System for Reduction of Liquid Helium Consumption

    Science.gov (United States)

    Adachi, Yoshiaki; Oyama, Daisuke; Kawai, Jun; Ogata, Hisanao; Uehara, Gen

    We are currently developing a magnetospinography (MSG) system for noninvasive functional imaging of the spinal cord. The MSG system is a device for observing a weak magnetic field accompanied by the neural activity of the spinal cord by using an array of low-temperature superconducting quantum interference device (SQUID) magnetic flux sensors. As in the case of other biomagnetic measurement systems such as the magnetoencephalography (MEG) system, the running cost of the MSG system is mainly dependent on the liquid helium (LHe) consumption of a dewar vessel. We integrated a cryocooler into the MSG system to reduce LHe consumption. A pulse tube cryocooler with a cooling power of 0.5Wat 4 K was placed adjacent to a magnetically shielded room and was directly connected to the thermal radiation shield of the dewar by an electrically isolated transfer tube. Cold helium gas was circulated between the cryocooler and the radiation shield. Consequently, the temperature of the radiation shield decreased below 40 K. Previous studies have shown that the detection of a weak magnetic field is often hindered by severe low-frequency band noise from the cryocooler. However, the band of the MSG signals is much higher than that of the cryocooler noise. Therefore, the noise can be filtered out and has a less detrimental effect on MSG measurement than on other biomagnetic field measurements such as MEG measurement. As a result, LHe consumption was reduced by 46%, with no increase in the noise floor.

  11. Cryocooled superconducting magnets for high magnetic fields at the HFLSM and future collaboration with the TML

    Science.gov (United States)

    Watanabe, K.; Nishijima, G.; Awaji, S.; Koyama, K.; Takahashi, K.; Kobayashi, N.; Kiyoshi, T.

    2006-11-01

    A hybrid magnet needs a large amount of liquid helium for operation. In order to make an easy-to-operate hybrid magnet system, we constructed a cryocooled 28 T hybrid magnet, consisting of an outer cryocooled 10 T superconducting magnet and an inner traditional water-cooled 19 T resistive magnet. As a performance test, the cryocooled hybrid magnet generated 27.5 T in a 32 mm room temperature experimental bore. As long as Nb3Sn superconducting wires are employed, the expected maximum high field generation in the cryocooled superconducting magnet will be 17 T at 5 K. We adopted the high temperature superconducting insert coil, employing Ag-sheathed Bi2Sr2Ca2Cu3O10superconducting tape. In combination with the low temperature 16.5 T back-up coil with a 174 mm cold bore, the cryocooled high temperature superconducting magnet successfully generated the total central field of 18.1 T in a 52 mm room temperature bore. As a next step, we start the collaboration with the National Institute for Materials Science for the new developmental works of a 30 T high temperature superconducting magnet and a 50 T-class hybrid magnet.

  12. Study on a Single-Stage 120 HZ Pulse Tube Cryocooler

    Science.gov (United States)

    Wu, Y. Z.; Gan, Z. H.; Qiu, L. M.; Chen, J.; Li, Z. P.

    2010-04-01

    Miniaturization of pulse tube cryocoolers is required for some particular applications where size and mass for devices are limited. In order to pack more cooling power in a small volume, higher operating frequencies are commonly used for Stirling-type pulse tube cryocoolers. To maintain high efficiency of the regenerator with a higher frequency, a higher charging pressure, smaller hydraulic diameters of regenerator material and a shorter regenerator length should be applied. A rapid growth of research and development on pulse tube cryocoolers operating at a high frequency over 100 Hz in the last 3 years has occurred. In this study, a single stage pulse tube cryocooler with 120 Hz to provide 10 W of lift at 80 K has been developed by using the numerical model, known as REGEN 3.2. Experiments performed on this cryocooler driven by a CFIC linear compressor show that a no-load temperature of 49.6 K was achieved and the net refrigeration power at 78.5 K was 8.0 W. The effect of pulse tube orientation was tested, and the copper velvet as a regenerator matrix was proposed for high frequency operation.

  13. Dynamic simulation of 10 kW Brayton cryocooler for HTS cable

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ho-Myung; Park, Chan Woo [Hong Ik University, Department of Mechanical Engineering, Seoul, 121-791 (Korea, Republic of); Yang, Hyung Suk; Hwang, Si Dole [KEPCO Research Institute, Daejeon, 305-760 (Korea, Republic of)

    2014-01-29

    Dynamic simulation of a Brayton cryocooler is presented as a partial effort of a Korean governmental project to develop 1∼3 km HTS cable systems at transmission level in Jeju Island. Thermodynamic design of a 10 kW Brayton cryocooler was completed, and a prototype construction is underway with a basis of steady-state operation. This study is the next step to investigate the transient behavior of cryocooler for two purposes. The first is to simulate and design the cool-down process after scheduled or unscheduled stoppage. The second is to predict the transient behavior following the variation of external conditions such as cryogenic load or outdoor temperature. The detailed specifications of key components, including plate-fin heat exchangers and cryogenic turbo-expanders are incorporated into a commercial software (Aspen HYSYS) to estimate the temporal change of temperature and flow rate over the cryocooler. An initial cool-down scenario and some examples on daily variation of cryocooler are presented and discussed, aiming at stable control schemes of a long cable system.

  14. An Optical Cryostat for Use in Microscopy Cooled by Stirling-Type Pulse Tube Cryocooler

    Science.gov (United States)

    Liubiao, Chen; Qiang, Zhou; Xiaoshuang, Zhu; Yuan, Zhou; Junjie, Wang

    The few products of an optical cryostat for use in microscopy in commercialapplications are generally cooled by liquid nitrogen, liquid helium or cryocoolers such as G-M cryocooler or G-M type pulse tube cryocooler (PTC). Sometimes it is not convenient to use G-M cryocooler or G-M type PTC because of its noise and big size; and in some places, liquid nitrogen, especially liquid helium, is not easily available. To overcome this limitation, an optical cryostat for use in microscopy cooled by a Stirling-type pulse tube cryocooler (SPTC) has been designed, built and tested. The refrigerator system SPTC is an important component of the optical cryostat; it has the advantages of compactness, high efficiency, and low vibration. For simplification and compactness, single-stage configuration with coaxial arrangement was employed in the developed SPTC. In order to lower the vibration, the separated configuration was adopted; its compressor and pulse tube are connected with a flexible connecting tube. At present, a lowest temperature of 20 K could be achieved. The temperature fluctuation can be controlled at ±10 mK by adjusting the input electric power to the compressor; and some considerations for further improvement will also be described in this paper.

  15. Progress Towards a 6-10 K Turbo-Brayton Cryocooler

    Science.gov (United States)

    Zagarola, M. V.; Cragin, K. J.; Breedlove, J. J.; Davis, T. M.

    2006-04-01

    Turbomachine-based Brayton (turbo-Brayton) cryocoolers are an ideal option for long-duration space missions. Key attributes inherent to the technology are high reliability, extremely low vibration emittance, and flexible packaging and integration with instruments and spacecraft systems. The first space implementation of the technology was the NICMOS Cryocooler, which is a single-stage unit that was installed on the Hubble Space Telescope in March 2002. This cryocooler provides 7 W of cooling at 70 K and has been operating for 3.3 years (July 2005) without degradation in performance. New developments at Creare are focused on two-stage configurations with load temperatures as low as 6 K. The lower temperatures and loads have required advances in component technologies to meet aggressive targets for cryocooler mass, size and performance. The development of the electronics, compressors and intermediate turboalternator for a 6-10 K cryocooler are complete. This paper summarizes our accomplishments on the completed components, and reviews our progress towards the development of the remaining critical components, a lightweight recuperator and a high performance low temperature turboalternator.

  16. Development of miniature Stirling cryocooler technology for Infrared Focal Plane array

    Directory of Open Access Journals (Sweden)

    Manmohan Singh

    2013-12-01

    Full Text Available A reliable miniature cryocooler is one of the basic and foremost requirements for successful operation of high performance cooled infrared focal plane array (IRFPA used for defence applications. Technological complexity and requirement of long duration fail-safe operation of the cryocooler demands robust design, fabrication and assembly with tolerances and, perfection of an array of sub-technologies. The paper presents the progress of the development activities in Stirling cryocooler technology at SSPL, which evolved through essential milestones like the development of single and dual piston linear motor driven split coolers to the state-of-the-art integral Brushless DC (BLDC motor crank-driven type highly miniaturized coolers of capacities ranging from 0.25 to 0.5W at 80K. The theoretical investigations in the design of Stirling cycle cryocooler have been reported and the issues related to the design aspects are discussed in sufficient details. Experimental results of cryocooler performance tests are also presented. The paper also focuses on regenerator design optimization. The results of optimizations have been shown at the end considering a sample data.Defence Science Journal, 2013, 63(6, pp.571-580, DOI:http://dx.doi.org/10.14429/dsj.63.5756

  17. Development of high-efficiency Stirling cryocoolers for high temperature superconducting motors

    Science.gov (United States)

    Nakano, K.; Yumoto, K.; Hiratsuka, Y.

    2015-12-01

    For wide spread high-temperature superconductor (HTS) devices, a cryocooler having COP of >0.1, with a compact size, light weight, high efficiency and high reliability is required. For practical use of superconductive devices, Sumitomo Heavy Industries, Ltd. (SHI) developed a high-efficiency Stirling type pulse tube cryocooler (STPC). The STPC had high reliability and low vibration. However, its efficiency was not enough to meet the demands of an HTS motor. To further improve the efficiency, we reconsidered the expander of cryocooler and developed a Stirling cryocooler (STC). Two prototype units of a compact, high-efficiency split Stirling cryocooler were designed, built and tested. With the second prototype unit, a cooling capacity of 151 W at 70 K and a minimum temperature of 33 K have been achieved with a compressor input power of 2.15 kW. Accordingly, COP of about 0.07 has been achieved. The detailed design of the prototype units and the experimental results will be reported in this paper.

  18. Development of 1 kW Stirling cryocooler using a linear compressor

    Science.gov (United States)

    Ko, J.; Kim, H.; Hong, Y. J.; Yeom, H.; In, S.; Park, S. J.

    2015-12-01

    Cryogenic cooling systems for HTS electric power devices require a reliable and efficient high-capacity cryocooler. A Striling cryocooler with a linear compressor can be a good candidate. It has advantages of low vibration and long maintenance cycle compared with a kinematic-driven Stirling cryocooler. In this study, we developed a dual-opposed linear compressor of 12 kW electric input power with two 6 kW linear motors. Electrical performance of the fabricated linear compressor is verified by experimental measurement of thrust constant. The developed Stirling cryocooler has a gamma-type configuration. The piston and displacer are supported with a flexure spring. A slit-type heat exchanger is adopted for the cold and warm-end, and the generated heat is rejected by cooling water. In the cooling performance test, waveforms of voltage, current, displacement and pressure are obtained and their amplitude and phase difference are analysed. The developed cryocooler reaches 47.8 K within 23.4 min. with no-load. Heat load tests shows a cooling capacity of 440 W at 78.1 K with 6.45 kW of electric input power and 19.4 of % Carnot COP.

  19. Sorption of dissolved organic matter and its effects on the atrazine sorption on soils

    Institute of Scientific and Technical Information of China (English)

    LING Wan-ting; WANG Hai-zhen; XU Jian-ming; GAO Yan-zheng

    2005-01-01

    The dissolved organic matter(DOM), water soluble organic matter derived from sewage sludge was separated into hydrophobic fraction(Ho) and hydrophilic fraction(Hi). The sorption of DOM and its fractions on soils and the effects of DOM sorption on a nonionic pesticide(atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-trazine)) distribution between soil and water were investigated using a batch equilibrium technique. The total DOM sorption on soils described by the Langmuir equation reached saturation as the DOMconcentration increased. The sorption of Ho fit the Freundlich model. In contrast, a negative retention evidently occurred as adding Hi at higher level in tested soils. The sorption of Ho dominated the total DOM sorption and the release of soil organic matter(SOM). Effects of DOM on the atrazine sorption by soils were DOM-concentration dependent and dominated by the interaction of atrazine, DOM, and soil solids. Generally, the presence of DOM with lower concentration promoted atrazine sorption on soils, namely the apparent partitioning constant( K; ) for atrazine sorption in the presence of DOM was larger than the distribution constant ( Kd ) without DOM; whereas the presence of DOM with higher concentration inhibited atrazine sorption(i. e., K; < Kd ) . The overall effects of DOM on atrazine sorption in soils might be related to the DOM sorption and the release of soil intrinsic organic matter into aqueous solution. The sorption of Ho on soils promoted the atrazine sorption on soil, while the release of SOM by Hi and the competitive sorption between Hi and atrazine on soil surface led to a decrease of atrazine sorption. Information provided in this work may contribute to a better understanding of the DOM sorption and its impacts on the contaminant soil-water distribution.

  20. Indium Sorption to Iron Oxides

    Science.gov (United States)

    White, S. J.; Sacco, S. A.; Hemond, H.; Hussain, F. A.; Runkel, R. L.; Walton-Day, K. E.; Kimball, B. A.; Shine, J. P.

    2014-12-01

    Indium is an increasingly important metal in semiconductors and electronics, and its use is growing rapidly as a semiconductive coating (as indium tin oxide) for liquid crystal displays (LCDs) and flat panel displays. It also has uses in important energy technologies such as light emitting diodes (LEDs) and photovoltaic cells. Despite its rapid increase in use, very little is known about the environmental behavior of indium, and concerns are being raised over the potential health effects of this emerging metal contaminant. One source of indium to the environment is acid mine drainage from the mining of lead, zinc, and copper sulfides. In our previous studies of a stream in Colorado influenced by acid mine drainage from lead and zinc mining activities, indium concentrations were found to be 10,000 times those found in uncontaminated rivers. However, the speciation and mobility of indium could not be reliably modeled because sorption constants to environmental sorbents have not been determined. In this study, we generate sorption constants for indium to ferrihydrite in the laboratory over a range of pHs, sorbent to sorbate ratios, and ionic strengths. Ferrihydrite is one of the most important sorbents in natural systems, and sorption to amorphous iron oxides such as ferrihydrite is thought to be one of the main removal mechanisms of metals from the dissolved phase in aqueous environments. Because of its relatively low solubility, we also find that indium hydroxide precipitation can dominate indium's partitioning at micromolar concentrations of indium. This precipitation may be important in describing indium's behavior in our study stream in Colorado, where modeling sorption to iron-oxides does not explain the complete removal of indium from the dissolved phase when the pH of the system is artificially raised to above 8. This study contributes much-needed data about indium's aqueous behavior, in order to better understand its fate, transport, and impacts in the

  1. Design and development of a four-cell sorption compressor based J-T cooler using R134a as working fluid

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, R. N. [Mechanical Engineering Department, Indian Institute of Technology Bombay, Mumbai - 400076, India and Government Engineering College Bharuch, Gujarat - 392002 (India); Bapat, S. L.; Atrey, M. D. [Mechanical Engineering Department, Indian Institute of Technology Bombay, Mumbai - 400076 (India)

    2014-01-29

    The need of a cooler with no electromagnetic interference and practically zero vibration has led to sorption compressor based Joule-Thomson (J-T) coolers. These are useful for sophisticated electronic, ground based and space borne systems. In a Sorption compressor, adsorbed gases are desorbed into a confined volume by raising temperature of the sorption bed resulting in an increase in pressure of the liberated gas. In order to have the system (compressor) functioning on a continuous basis, with almost a constant gas flow rate, multiple cells are used with the adaptation of Temperature Swing Adsorption (TSA) process. As the mass of the desorbed gas dictates the compressor throughput, a combination of sorbent material with high adsorption capacity for a chosen gas or gas mixture has to be selected for efficient operation of the compressor. Commercially available (coconut-shell base) activated carbon has been selected for the present application. The characterization study for variation of discharge pressure is used to design the Four-cell sorption compressor based cryocooler with a desired output. Apart from compressor, the system includes a) After cooler b) Return gas heat exchanger c) capillary tube as the J-T expansion device and d) Evaporator.

  2. Design and development of a four-cell sorption compressor based J-T cooler using R134a as working fluid

    Science.gov (United States)

    Mehta, R. N.; Bapat, S. L.; Atrey, M. D.

    2014-01-01

    The need of a cooler with no electromagnetic interference and practically zero vibration has led to sorption compressor based Joule-Thomson (J-T) coolers. These are useful for sophisticated electronic, ground based and space borne systems. In a Sorption compressor, adsorbed gases are desorbed into a confined volume by raising temperature of the sorption bed resulting in an increase in pressure of the liberated gas. In order to have the system (compressor) functioning on a continuous basis, with almost a constant gas flow rate, multiple cells are used with the adaptation of Temperature Swing Adsorption (TSA) process. As the mass of the desorbed gas dictates the compressor throughput, a combination of sorbent material with high adsorption capacity for a chosen gas or gas mixture has to be selected for efficient operation of the compressor. Commercially available (coconut-shell base) activated carbon has been selected for the present application. The characterization study for variation of discharge pressure is used to design the Four-cell sorption compressor based cryocooler with a desired output. Apart from compressor, the system includes a) After cooler b) Return gas heat exchanger c) capillary tube as the J-T expansion device and d) Evaporator.

  3. Fast Response Temperature Measurements in Stirling Cycle Cryocooler Components

    Science.gov (United States)

    Kar, K.; Dadd, M. W.; Bailey, P. B.; Stone, C. R.

    2008-03-01

    One reason that heat transfer processes are not well understood is the difficulty of obtaining reliable temperature measurements when gas temperatures vary rapidly. In the work described here gas temperatures have been measured using a fine wire resistance thermometer with a 3.8 micron active sensor. The equipment represented the basic elements of a cryocooler: a clearance seal linear compressor and a wire mesh regenerator. Both were operated close to ambient temperature, with gas temperatures being measured close to the regenerator. The test rig was run at different volume ratios, frequencies (8-50 Hz), gases and filling pressures (1-26 bar). The waveforms of the gas temperature were found to vary dramatically for differing flow regimes. The results suggested that the thermometer was measuring the temperatures of two distinct volumes of gas, and that the gas must remain stratified in the compression space. A flow transition was identified from the cycle-by-cycle variations in temperature. The critical Reynolds number was determined to be 9.6-11. At the critical condition, the temperature was so unstable that fluctuations up to 250 Hz were observed. A series of validation tests have confirmed that the observed temperatures were not artifacts.

  4. Vibrational stability of a cryocooled horizontal double-crystal monochromator

    Science.gov (United States)

    Kristiansen, Paw; Johansson, Ulf; Ursby, Thomas; Jensen, Brian Norsk

    2016-01-01

    The vibrational stability of a horizontally deflecting double-crystal monochromator (HDCM) is investigated. Inherently a HDCM will preserve the vertical beam stability better than a ‘normal’ vertical double-crystal monochromator as the vibrations of a HDCM will almost exclusively affect the horizontal stability. Here both the relative pitch vibration between the first and second crystal and the absolute pitch vibration of the second crystal are measured. All reported measurements are obtained under active cooling by means of flowing liquid nitrogen (LN2). It is found that it is favorable to circulate the LN2 at high pressures and low flow rates (up to 5.9 bar and down to 3 l min−1 is tested) to attain low vibrations. An absolute pitch stability of the second crystal of 18 nrad RMS, 2–2500 Hz, and a relative pitch stability between the two crystals of 25 nrad RMS, 1–2500 Hz, is obtained under cryocooling conditions that allow for 1516 W to be adsorbed by the LN2 before it vaporizes. PMID:27577758

  5. Hydrodynamic parameters of mesh fillers relevant to miniature regenerative cryocoolers

    Science.gov (United States)

    Landrum, E. C.; Conrad, T. J.; Ghiaasiaan, S. M.; Kirkconnell, Carl S.

    2010-06-01

    Directional hydrodynamic parameters of two fine-mesh porous materials that are suitable for miniature regenerative cryocoolers were studied under steady and oscillating flows of helium. These materials included stacked discs of #635 stainless steel (wire diameter of 20.3 μm) and #325 phosphor bronze (wire diameter of 35.6 μm) wire mesh screens, which are among the commercially available fillers for use in small-scale regenerators and heat exchangers, respectively. Experiments were performed in test sections in which pressure variations across these fillers, in the axial and lateral (radial) directions, were measured under steady and oscillatory flows. The directional permeability and Forchheimer's inertial coefficient were then obtained by using a Computational Fluid Dynamics (CFD)-assisted method. The oscillatory flow experiments covered a frequency range of 50-200 Hz. The results confirmed the importance of anisotropy in the mesh screen fillers, and indicated differences between the directional hydrodynamic resistance parameters for steady and oscillating flow regimes.

  6. Sorption Energy Maps of Clay Mineral Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Cygan, Randall T.; Kirkpatrick, R. James

    1999-07-19

    A molecular-level understanding of mineral-water interactions is critical for the evaluation and prediction of the sorption properties of clay minerals that may be used in various chemical and radioactive waste disposal methods. Molecular models of metal sorption incorporate empirical energy force fields, based on molecular orbital calculations and spectroscopic data, that account for Coulombic, van der Waals attractive, and short-range repulsive energies. The summation of the non-bonded energy terms at equally-spaced grid points surrounding a mineral substrate provides a three dimensional potential energy grid. The energy map can be used to determine the optimal sorption sites of metal ions on the exposed surfaces of the mineral. By using this approach, we have evaluated the crystallographic and compositional control of metal sorption on the surfaces of kaolinite and illite. Estimates of the relative sorption energy and most stable sorption sites are derived based on a rigid ion approximation.

  7. A 63 K phase change unit integrating with pulse tube cryocoolers

    Science.gov (United States)

    Chunhui, Kong; Liubiao, Chen; Sixue, Liu; Yuan, Zhou; Junjie, Wang

    2017-02-01

    This article presents the design and computer model results of an integrated cooler system which consists of a single stage pulse tube cryocooler integrated with a small amount of a phase change material. A cryogenic thermal switch was used to thermally connect the phase change unit to the cold end of the cryocooler. During heat load operation, the cryogenic thermal switch is turned off to avoid vibrations. The phase change unit absorbs heat loads by melting a substance in a constant pressure-temperature-volume process. Once the substance has been melted, the cryogenic thermal turned on, the cryocooler can then refreeze the material. Advantages of this type of cooler are no vibrations during sensor operations; the ability to absorb increased heat loads; potentially longer system lifetime; and a lower mass, volume and cost. A numerical model was constructed from derived thermodynamic relationships for the cooling/heating and freezing/melting processes.

  8. The development of a range of small mechanical cryocoolers for space and avionic applications

    Science.gov (United States)

    Hocking, Barry

    1990-10-01

    The design features of a mechanical cryocooler, including a compressor, displacer, connecting pipe, and electronic controller are described. The complete system is filled with helium gas to a pressure of 10 bar. Long life, low exported vibration, and good refrigeration within the defined temperature range are emphasized as the main requirements. A number of improvements with regard to the reliability required for long-life space coolers are outlined, and emphasis is placed on the improved sealing for the helium gas and the outgassing properties of all components. Scaling up of the cryocooler design for increased refrigeration is reviewed as well as a space-system interface. Testing of space-rated cryocooler systems producing nominal 0.5 W and 1 W cooling at 65 K from a single system is discussed.

  9. New application of plate-fin heat exchanger with regenerative cryocoolers

    Science.gov (United States)

    Chang, Ho-Myung; Gwak, Kyung Hyun

    2015-09-01

    A design idea is newly proposed and investigated for the application of plate-fin heat exchanger (PFHX) with regenerative cryocoolers. The role of this heat exchanger is to effectively absorb heat from the stream of coolant and deliver it to the cold-head of a cryocooler. While various types of tubular HX's have been developed so far, a small PFHX could be more useful for this purpose by taking advantage of compactness and design flexibility. In order to confirm the feasibility and effectiveness, a prototype of aluminum-brazed PFHX is designed, fabricated, and tested with a single-stage GM cryocooler in experiments for subcooling liquid nitrogen from 78 K to 65-70 K. The results show that the PFHX is 30-50% more effective in cooling rate than the tubular HX's. Several potential applications of PFHX are presented and discussed with specific design concepts.

  10. Manganese Nitride Sorption Joule-Thomson Refrigerator

    Science.gov (United States)

    Jones, Jack A.; Phillips, Wayne M.

    1992-01-01

    Proposed sorption refrigeration system of increased power efficiency combines MnxNy sorption refrigeration stage with systems described in "Regenerative Sorption Refrigerator" (NPO-17630). Measured pressure-vs-composition isotherms for reversible chemisorption of N2 in MnxNy suggest feasibility to incorporate MnxNy chemisorption stage in Joule-Thomson cryogenic system. Discovery represents first known reversible nitrogen chemisorption compression system. Has potential in nitrogen-isotope separation, nitrogen purification, or contamination-free nitrogen compression.

  11. Mixed-refrigerant Joule-Thomson (MR JT) mini-cryocoolers

    Science.gov (United States)

    Tzabar, Nir

    2014-01-01

    This paper presents the progress in our ongoing research on Mixed-Refrigerant (MR) Joule-Thomson (JT) cryocoolers. The research begun by exploring different MRs and testing various compressors: oil-lubricated and oil-free, reciprocating and linear, custom-made and commercial. Closed-cycle JT cryocoolers benefit from the fact that the compressor might be located far from the cold-end and thus there are no moving parts, no vibrations, and no heat emission near the cold-end. As a consequence, the compressor may be located where there are no severe size limitations, its heat can be conveniently removed, and it can be easily maintained. However, in some applications there is still a demand for a small compressor to drive a JT cryocooler although it is located far from the cooled device. Recently, we have developed a miniature oil-free compressor for MR JT cryocoolers that weighs about 700 g and its volume equals about 300 cc. The cryocooler operates with a MR that contains Ne, N2, and Hydrocarbons. This MR has been widely investigated with different compressors and varying operating conditions and proved to be stable. The current research investigates the performances of MR JT mini-cryocooler operating with the MR mentioned above, driven with our miniature compressor, and a cold-finger prototype. A Dewar with heat load of about 230 mW is cooled to about 80 K at ambient temperatures between 0°C and 40°C. The experimental results obtained are stable and demonstrate the ability to control the cooling temperature by changing the rotation speed of the compressor.

  12. Numerical study of a magnesium hydride tank

    Science.gov (United States)

    Delhomme, Baptiste; de Rango, Patricia; Marty, Philippe

    2012-11-01

    Hydrogen storage in metal hydride tanks (MHT) is a very promising solution. Several experimental tanks, studied by different teams, have already proved the feasibility and the interesting performances of this solution. However, in much cases, an optimization of tank geometry is still needed in order to perform fast hydrogen loading. The development of efficient numerical tools is a key issue for MHT design and optimization. We propose a simple model representing a metal hydride tank exchanging its heat of reaction with a thermal fluid flow. In this model, the radial and axial discretisations have been decoupled by using Matlab® one-dimensional tools. Calculations are compared to experimental results obtained in a previous study. A good agreement is found for the loading case. The discharging case shows some discrepancies, which are discussed in this paper.

  13. The electrochemical impedance of metal hydride electrodes

    DEFF Research Database (Denmark)

    Valøen, Lars Ole; Lasia, Andrzej; Jensen, Jens Oluf

    2002-01-01

    The electrochemical impedance responses for different laboratory type metal hydride electrodes were successfully modeled and fitted to experimental data for AB5 type hydrogen storage alloys as well as one MgNi type electrode. The models fitted the experimental data remarkably well. Several AC......, explaining the experimental impedances in a wide frequency range for electrodes of hydride forming materials mixed with copper powder, were obtained. Both charge transfer and spherical diffusion of hydrogen in the particles are important sub processes that govern the total rate of the electrochemical...... hydrogen absorption/desorption reaction. To approximate the experimental data, equations describing the current distribution in porous electrodes were needed. Indications of one or more parallel reduction/oxidation processes competing with the electrochemical hydrogen absorption/desorption reaction were...

  14. Performance of the SITP 35K two-stage Stirling cryocooler

    Science.gov (United States)

    Liu, Dongyu; Li, Ao; Li, Shanshan; Wu, Yinong

    2010-04-01

    This paper presents the design, development, optimization experiment and performance of the SITP two-stage Stirling cryocooler. The geometry size of the cooler, especially the diameter and length of the regenerator were analyzed. Operating parameters by experiments were optimized to maximize the second stage cooling performance. In the test the cooler was operated at various drive frequency, phase shift between displacer and piston, fill pressure. The experimental results indicate that the cryocooler has a higher efficiency with a performance of 0.85W at 35K with a compressor input power of 56W at a phase shift of 65°, an operating frequency of 40Hz, 1MPa fill pressure.

  15. ELISA: a cryocooled 10 GHz oscillator with 10-15 frequency stability

    CERN Document Server

    Grop, S; Bazin, N; Kersale, Y; Rubiola, E; Langham, C; Oxborrow, M; Clapton, D; Walker, S; De Vicente, J; Giordano, V

    2009-01-01

    This article reports the design, the breadboarding and the validation of an ultra-stable Cryogenic Sapphire Oscillator operated in an autonomous cryocooler. The objective of this project was to demonstrate the feasibility of a frequency stability of 3x10-15 between 1 s and 1,000 s for the European Space Agency deep space stations. This represents the lowest fractional frequency instability ever achieved with cryocoolers. The preliminary results presented in this paper validate the design we adopted for the sapphire resonator, the cold source and the oscillator loop.

  16. Investigation on a Single-stage Coaxial Pulse Tube Cryocooler for Small Particle Detectors at CERN

    CERN Document Server

    Haug, F; Essler, J; Koettig, T; Wu, J H

    2009-01-01

    A single-stage coaxial pulse tube cryocooler has been developed for cooling small particle tracking detectors needed for future luminosity upgrades of the LHC. It is designed for remote operation in high radiation areas of the tunnel with restricted space. It features novel phase-adjusting mechanisms integrated into the warm flange. This flange is cooled with ambient air to reach a simple and compact design. The dimensions of the cold-finger are 24 mm diameter and 170 mm length. The measured no-load temperature is 52 K and the pulse tube cryocooler provides a cooling capacity of 5 W at 80 K.

  17. ELISA: a cryocooled 10 GHz oscillator with 10(-15) frequency stability.

    Science.gov (United States)

    Grop, S; Bourgeois, P Y; Bazin, N; Kersalé, Y; Rubiola, E; Langham, C; Oxborrow, M; Clapton, D; Walker, S; De Vicente, J; Giordano, V

    2010-02-01

    This article reports the design, the breadboarding, and the validation of an ultrastable cryogenic sapphire oscillator operated in an autonomous cryocooler. The objective of this project was to demonstrate the feasibility of a frequency stability of 3x10(-15) between 1 and 1000 s for the European Space Agency deep space stations. This represents the lowest fractional frequency instability ever achieved with cryocoolers. The preliminary results presented in this paper validate the design we adopted for the sapphire resonator, the cold source, and the oscillator loop.

  18. Influence of regenerator matrix and working fluid on optimisation of design parameters of Stirling cryocoolers

    Science.gov (United States)

    Atrey, M. D.; Bapat, S. L.; Narayankhedkar, K. G.

    The performance of Stirling cryocooler is governed by principal designparameters. The optimum combination of these design parameters gives maximum refrigeration effect and minimum desired efforts. The performance of the cryocooler depends significantly on the regenerator functioning and the working fluids. The mesh size of the regenerator affects dead space, pressure drop, regenerator effectiveness, etc. The working fluids differ in their thermal properties and therefore affect the performance significantly, The present paper aims to study the influence of regenerator matrix and working fluids on these design parameters. The matrix material considered is Phosphor Bronze while the working fluids considered are Helium and Hydrogen.

  19. Development of the mechanical cryocooler system for the Sea Land Surface Temperature Radiometer

    Science.gov (United States)

    Camilletti, Adam; Burgess, Christopher; Donchev, Anton; Watson, Stuart; Weatherstone Akbar, Shane; Gamo-Albero, Victoria; Romero-Largacha, Victor; Caballero-Olmo, Gema

    2014-11-01

    The Sea Land Surface Temperature Radiometer is a dual view Earth observing instrument developed as part of the European Global Monitoring for Environment and Security programme. It is scheduled for launch on two satellites, Sentinel 3A and 3B in 2014. The instrument detectors are cooled to below 85 K by two split Stirling Cryocoolers running in hot redundancy. These coolers form part of a cryocooler system that includes a support structure and drive electronics. Aspects of the system design, including control and reduction of exported vibration are discussed; and results, including thermal performance and exported vibration from the Engineering Model Cryooler System test campaign are presented.

  20. Nickel metal hydride LEO cycle testing

    Science.gov (United States)

    Lowery, Eric

    1995-01-01

    The George C. Marshall Space Flight Center is working to characterize aerospace AB5 Nickel Metal Hydride (NiMH) cells. The cells are being evaluated in terms of storage, low earth orbit (LEO) cycling, and response to parametric testing (high rate charge and discharge, charge retention, pulse current ability, etc.). Cells manufactured by Eagle Picher are the subjects of the evaluation. There is speculation that NiMH cells may become direct replacements for current Nickel Cadmium cells in the near future.

  1. Storing hydrogen in the form of light alloy hydrides

    Science.gov (United States)

    Freund, E.; Gillerm, C.

    1981-01-01

    Different hydrides are investigated to find a system with a sufficiently high storage density (at least 3%). The formation of hydrides with light alloys is examined. Reaction kinetics for hydride formation were defined and applied to the systems Mg-Al-H, Mg-Al-Cu-H, Ti-Al-H, Ti-Al-Cu-H, and Ti-Al-Ni-H. Results indicate that the addition of Al destabilizes MgH2 and TiH2 hydrides while having only a limited effect on the storage density.

  2. Plasmonic hydrogen sensing with nanostructured metal hydrides.

    Science.gov (United States)

    Wadell, Carl; Syrenova, Svetlana; Langhammer, Christoph

    2014-12-23

    In this review, we discuss the evolution of localized surface plasmon resonance and surface plasmon resonance hydrogen sensors based on nanostructured metal hydrides, which has accelerated significantly during the past 5 years. We put particular focus on how, conceptually, plasmonic resonances can be used to study metal-hydrogen interactions at the nanoscale, both at the ensemble and at the single-nanoparticle level. Such efforts are motivated by a fundamental interest in understanding the role of nanosizing on metal hydride formation processes in the quest to develop efficient solid-state hydrogen storage materials with fast response times, reasonable thermodynamics, and acceptable long-term stability. Therefore, a brief introduction to the thermodynamics of metal hydride formation is also given. However, plasmonic hydrogen sensors not only are of academic interest as research tool in materials science but also are predicted to find more practical use as all-optical gas detectors in industrial and medical applications, as well as in a future hydrogen economy, where hydrogen is used as a carbon free energy carrier. Therefore, the wide range of different plasmonic hydrogen sensor designs already available is reviewed together with theoretical efforts to understand their fundamentals and optimize their performance in terms of sensitivity. In this context, we also highlight important challenges to be addressed in the future to take plasmonic hydrogen sensors from the laboratory to real applications in devices, including poisoning/deactivation of the active materials, sensor lifetime, and cross-sensitivity toward other gas species.

  3. Plutonium sorption and desorption behavior on bentonite.

    Science.gov (United States)

    Begg, James D; Zavarin, Mavrik; Tumey, Scott J; Kersting, Annie B

    2015-03-01

    Understanding plutonium (Pu) sorption to, and desorption from, mineral phases is key to understanding its subsurface transport. In this work we study Pu(IV) sorption to industrial grade FEBEX bentonite over the concentration range 10(-7)-10(-16) M to determine if sorption at typical environmental concentrations (≤10(-12) M) is the same as sorption at Pu concentrations used in most laboratory experiments (10(-7)-10(-11) M). Pu(IV) sorption was broadly linear over the 10(-7)-10(-16) M concentration range during the 120 d experimental period; however, it took up to 100 d to reach sorption equilibrium. At concentrations ≥10(-8) M, sorption was likely affected by additional Pu(IV) precipitation/polymerization reactions. The extent of sorption was similar to that previously reported for Pu(IV) sorption to SWy-1 Na-montmorillonite over a narrower range of Pu concentrations (10(-11)-10(-7) M). Sorption experiments with FEBEX bentonite and Pu(V) were also performed across a concentration range of 10(-11)-10(-7) M and over a 10 month period which allowed us to estimate the slow apparent rates of Pu(V) reduction on a smectite-rich clay. Finally, a flow cell experiment with Pu(IV) loaded on FEBEX bentonite demonstrated continued desorption of Pu over a 12 day flow period. Comparison with a desorption experiment performed with SWy-1 montmorillonite showed a strong similarity and suggested the importance of montorillonite phases in controlling Pu sorption/desorption reactions on FEBEX bentonite.

  4. High-resolution X-ray crystal structure of bovine H-protein using the high-pressure cryocooling method

    Energy Technology Data Exchange (ETDEWEB)

    Higashiura, Akifumi, E-mail: hgsur-a@protein.osaka-u.ac.jp [Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Ohta, Kazunori; Masaki, Mika; Sato, Masaru [Japan Aerospace Exploration Agency, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan); Inaka, Koji [Maruwa Foods and Biosciences Inc., Nara 639-1123 (Japan); Tanaka, Hiroaki [Confocal Science Inc., Tokyo 101-0032 (Japan); Nakagawa, Atsushi [Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2013-11-01

    Using the high-pressure cryocooling method, the high-resolution X-ray crystal structure of bovine H-protein was determined at 0.86 Å resolution. This is the first ultra-high-resolution structure obtained from a high-pressure cryocooled crystal. Recently, many technical improvements in macromolecular X-ray crystallography have increased the number of structures deposited in the Protein Data Bank and improved the resolution limit of protein structures. Almost all high-resolution structures have been determined using a synchrotron radiation source in conjunction with cryocooling techniques, which are required in order to minimize radiation damage. However, optimization of cryoprotectant conditions is a time-consuming and difficult step. To overcome this problem, the high-pressure cryocooling method was developed (Kim et al., 2005 ▶) and successfully applied to many protein-structure analyses. In this report, using the high-pressure cryocooling method, the X-ray crystal structure of bovine H-protein was determined at 0.86 Å resolution. Structural comparisons between high- and ambient-pressure cryocooled crystals at ultra-high resolution illustrate the versatility of this technique. This is the first ultra-high-resolution X-ray structure obtained using the high-pressure cryocooling method.

  5. Experimental Studies on a Single Stage Stirling Type Pulse Tube Cryocooler Driven by Oil-Lubricated Compressor

    Science.gov (United States)

    Jia, Ren; Jianying, Hu; Ercang, Luo; Xiaotao, Wang

    2010-04-01

    Because lubricating oil for moving parts is not allowed to go into the pulse tube cryocooler, Stirling type pulse tube cryocoolers are generally driven by oil-free compressors although oil-lubricated compressors are much cheaper and facile. Recently, it was proposed that an acoustic transparent and oil blocking diaphragm could be employed to separate the compressor and the cryocooler. Thus, the cryocooler can be driven by oil-lubricated compressors. In this paper, a pulse tube cryocooler is designed to match a crankcase compressor. Although the efficiency of the crankcase compressor is lower compared with the oil-free linear compressor, the crankcase compressor can easily work at lower frequency which results in higher efficiency for the cryocooler. So the relative high performance of the whole system can be maintained. In this system, the cryocooler delivers 28.5 W of cooling at 80 K with 680 W of electrical input power and operates at 15 Hz. The corresponding Carnot efficiency is 11.52%.

  6. Nitrate Sorption in an Agricultural Soil Profile

    Directory of Open Access Journals (Sweden)

    Wissem Hamdi

    2013-01-01

    Full Text Available Increasing concentrations of in surface water and groundwater can cause ecological and public health effects and has come under increased scrutiny by both environmental scientists and regulatory agencies. For many regions though, including the Sahel of Tunisia, little is known about the sorption capacity of soils. In this project we measured sorption by a profile of an iso-humic soil from Chott Meriem, Tunisia. Soil samples were collected from four soil depths (0–25, 25–60, 60–90, and 90–120 cm on 1 June 2011, and their sorption capacity was determined using batch experiments under laboratory conditions. The effects of contact time, the initial concentration, and the soil-solution ratio on sorption were investigated. In general, the results suggested that was weakly retained by the Chott Meriem soil profile. The quantity of sorption increased with depth, contact time, initial concentration, and soil-solution ratios. To evaluate the sorption capacities of the soil samples at concentrations ranging between 25 and 150 mg L−1 experimental data were fitted to both Freundlich and Langmuir isotherm sorption models. The results indicated that Freundlich model was better for describing sorption in this soil profile.

  7. Phenanthrene Sorption on Biochar-Amended Soils

    DEFF Research Database (Denmark)

    Kumari, K. G I D; Moldrup, Per; Paradelo, Marcos

    2014-01-01

    on their influences on the sorption of environmental contaminants. In a field-based study at two experimental sites in Denmark, we investigated the effect of birch wood-derived biochar (Skogans kol) on the sorption of phenanthrene in soils with different properties. The soil sorption coefficient, Kd (L kg-1......), of phenanthrene was measured on sandy loam and loamy sand soils which have received from zero up to 100 t ha-1 of biochar. Results show that birch wood biochar had a higher Kd compared to soils. Furthermore, the application of birch wood biochar enhanced the sorption of phenanthrene in agricultural soils...... carbon, while it negatively correlated with clay content. The results also revealed that biochar-mineral interactions play an important role in the sorption of phenanthrene in biochar-amended soil....

  8. Sorption kinetics of ofloxacin in soils and mineral particles.

    Science.gov (United States)

    Pan, Bo; Wang, Peng; Wu, Min; Li, Jing; Zhang, Di; Xiao, Di

    2012-12-01

    The environmental behavior of antibiotics is not well known and the precise environmental risk assessment is not practical. This study investigated the sorption kinetics of ofloxacin, a widely used antibiotics, on soil particles with different organic carbon contents as well as soil components (a humic acid, ferric oxide and kaolinite). Two-compartment sorption kinetics were mathematically recognized (except ferric oxide because of its very fast sorption). The apparent sorption rate and the contribution of fast sorption compartment decreased with the increased organic carbon content with the exception of humic acid, suggesting that the slow sorption sites were partially located in organo-mineral complex. The OFL concentration-dependent sorption kinetics suggested that the slow sorption compartment was not controlled by diffusion process as indicated by slower sorption at higher OFL loading. The difference between OFL sorption kinetics and those of hydrophobic organic contaminants was discussed and possible mechanism of OFL two-compartment sorption was proposed.

  9. Sorption kinetics of hexadecyltrimethylammonium on natural clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.

    1999-09-14

    Sorption kinetics of hexadecyltrimethylammonium (HDTMA) chloride on a natural clinoptilolite was studied in this research. The amount of HDTMA sorbed is a function of the initial HDTMA input and the sorption time. When the initial HDTMA input is less than the external cation-exchange capacity of the clinoptilolite, the HDTMA sorption is fast and equilibrium can be established in 1 h. As the initial HDTMA input is greater than the external cation-exchange capacity of clinoptilolite, which will result in more than a monolayer HDTMA surface coverage, the time for HDTMA sorption to reach equilibrium increases exponentially. The HDTMA sorption maximum on clinoptilolite increases logarithmically with mixing time. The counterion solution concentration data suggest that at the initial stage HDTMA molecules sorb on the zeolite via micelle forms, which is manifested by a decrease in chloride solution concentration with time. When HDTMA solution concentration is depleted to less than its critical micelle concentration, the adsorbed micelles (admicelles) rearrange themselves to a more stable monolayer or bilayer configuration, which is reflected by an increase in counterion solution concentration due to the desorption of chloride from admicelles. The time required for the surface rearrangement increases exponentially as the HDTMA input increases. The data of HDTMA sorption kinetics were fitted to different kinetic models, and the parabolic diffusion model fits the data best for the HDTMA sorption, counterion sorption at the initial stage and counterion desorption at the rearrangement stage. Thus, the sorption of HDTMA on clinoptilolite surfaces is diffusion controlled. The results also indicate that it is incomplete to discuss surfactant sorption without counterion concentration data.

  10. James Webb Space Telescope Mid Infra-Red Instrument Pulse-Tube Cryocooler Electronics

    Science.gov (United States)

    Harvey, D.; Flowers, T.; Liu, N.; Moore, K.; Tran, D.; Valenzuela, P.; Franklin, B.; Michaels, D.

    2013-01-01

    The latest generation of long life, space pulse-tube cryocoolers require electronics capable of controlling self-induced vibration down to a fraction of a newton and coldhead temperature with high accuracy down to a few kelvin. Other functions include engineering diagnostics, heater and valve control, telemetry and safety protection of the cryocooler subsystem against extreme environments and operational anomalies. The electronics are designed to survive the thermal, vibration, shock and radiation environment of launch and orbit, while providing a design life in excess of 10 years on-orbit. A number of our current generation high reliability radiation-hardened electronics units are in various stages of integration on several space flight payloads. This paper describes the features and performance of our latest flight electronics designed for the pulse-tube cryocooler that is the pre-cooler for a closed cycle Joule-Thomson cooler providing 6K cooling for the James Webb Space Telescope (JWST) Mid Infra-Red Instrument (MIRI). The electronics is capable of highly accurate temperature control over the temperature range from 4K to 15K. Self-induced vibration is controlled to low levels on all harmonics up to the 16th. A unique active power filter controls peak-to-peak reflected ripple current on the primary power bus to a very low level. The 9 kg unit is capable of delivering 360W continuous power to NGAS's 3-stage pulse-tube High-Capacity Cryocooler (HCC).

  11. Analysis and comparison of different phase shifters for Stirling pulse tube cryocooler

    DEFF Research Database (Denmark)

    Lei, Tian; Pfotenhauer, John M.; Zhou, Wenjie

    2016-01-01

    Investigations of phase shifters and power recovery mechanisms are of sustainable interest for developing Stirling pulse tube cryocoolers (SPTC) with higher power density, more compact design and higher efficiency. This paper investigates the phase shifting capacity and the applications of four d...

  12. Study on a high capacity two-stage free piston Stirling cryocooler working around 30 K

    Science.gov (United States)

    Wang, Xiaotao; Zhu, Jian; Chen, Shuai; Dai, Wei; Li, Ke; Pang, Xiaomin; Yu, Guoyao; Luo, Ercang

    2016-12-01

    This paper presents a two-stage high-capacity free-piston Stirling cryocooler driven by a linear compressor to meet the requirement of the high temperature superconductor (HTS) motor applications. The cryocooler system comprises a single piston linear compressor, a two-stage free piston Stirling cryocooler and a passive oscillator. A single stepped displacer configuration was adopted. A numerical model based on the thermoacoustic theory was used to optimize the system operating and structure parameters. Distributions of pressure wave, phase differences between the pressure wave and the volume flow rate and different energy flows are presented for a better understanding of the system. Some characterizing experimental results are presented. Thus far, the cryocooler has reached a lowest cold-head temperature of 27.6 K and achieved a cooling power of 78 W at 40 K with an input electric power of 3.2 kW, which indicates a relative Carnot efficiency of 14.8%. When the cold-head temperature increased to 77 K, the cooling power reached 284 W with a relative Carnot efficiency of 25.9%. The influences of different parameters such as mean pressure, input electric power and cold-head temperature are also investigated.

  13. Pulse tube cryocooler with self-cancellation of cold stage vibration

    CERN Document Server

    Suzuki, T; Ikushima, Y; Li, R; Sato, N; Shintomi, T; Tomaru, T; Yamamoto, A

    2006-01-01

    We experimentally demonstrated a new method for reducing the vibration of the cold stage of a cryocooler. Comparing the RMS amplitude with the case of no phase shift of the driving gas pressure between the two pairs, the longitudinal vibration of the cold stage was reduced by 96.1% at 126 K by supplying gas pressure with 180 degrees of phase shift.

  14. Investigation of pressure drop in capillary tube for mixed refrigerant Joule-Thomson cryocooler

    Energy Technology Data Exchange (ETDEWEB)

    Ardhapurkar, P. M. [Mechanical Engineering Department, Indian Institute of Technology Bombay, Mumbai, MS 400 076 India and S. S. G. M. College of Engineering Shegaon, MS 444 203 (India); Sridharan, Arunkumar; Atrey, M. D. [Mechanical Engineering Department, Indian Institute of Technology Bombay, Mumbai, MS 400 076 (India)

    2014-01-29

    A capillary tube is commonly used in small capacity refrigeration and air-conditioning systems. It is also a preferred expansion device in mixed refrigerant Joule-Thomson (MR J-T) cryocoolers, since it is inexpensive and simple in configuration. However, the flow inside a capillary tube is complex, since flashing process that occurs in case of refrigeration and air-conditioning systems is metastable. A mixture of refrigerants such as nitrogen, methane, ethane, propane and iso-butane expands below its inversion temperature in the capillary tube of MR J-T cryocooler and reaches cryogenic temperature. The mass flow rate of refrigerant mixture circulating through capillary tube depends on the pressure difference across it. There are many empirical correlations which predict pressure drop across the capillary tube. However, they have not been tested for refrigerant mixtures and for operating conditions of the cryocooler. The present paper assesses the existing empirical correlations for predicting overall pressure drop across the capillary tube for the MR J-T cryocooler. The empirical correlations refer to homogeneous as well as separated flow models. Experiments are carried out to measure the overall pressure drop across the capillary tube for the cooler. Three different compositions of refrigerant mixture are used to study the pressure drop variations. The predicted overall pressure drop across the capillary tube is compared with the experimentally obtained value. The predictions obtained using homogeneous model show better match with the experimental results compared to separated flow models.

  15. Harmonic frequency mixing using high Tc superconductor Josephson junction mounted on pulse tube cryocooler

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A frequency mixing system including microwave coupling and intermediate frequency (IF) measurement arrangements is esigned. In lieu of liquid nitrogen, a pulse tube cryocooler is used to cool the whole system. With YBa2Cu3O7/Yttrium stabilized irconia (YBCO/YSZ) bicrystal Josephson junction as the mixing element, 36th harmonic frequency mixing at the 8 mm waveband is obtained.

  16. Construction and test of a cryocooler-cooled low-Tc SQUID gradiometer system

    NARCIS (Netherlands)

    Rijpma, A.P.; Krooshoop, H.J.G.; Lefevere, M.W.; Leeuwen, van E.P.; Holland, H.J.; Haken, ten B.; Brake, ter H.J.M.

    2008-01-01

    A cryocooler-cooled low-Tc SQUID gradiometer system was designed and constructed. It is based on a 4 K GM-cooler that is positioned several meters from the measuring head containing the SQUID sensors. The cooling power is transported by means of a circulating helium flow. Thus, there are three main

  17. James Webb Space Telescope Mid Infra-Red Instrument Pulse-Tube Cryocooler Electronics

    Science.gov (United States)

    Harvey, D.; Flowers, T.; Liu, N.; Moore, K.; Tran, D.; Valenzuela, P.; Franklin, B.; Michaels, D.

    2013-01-01

    The latest generation of long life, space pulse-tube cryocoolers require electronics capable of controlling self-induced vibration down to a fraction of a newton and coldhead temperature with high accuracy down to a few kelvin. Other functions include engineering diagnostics, heater and valve control, telemetry and safety protection of the cryocooler subsystem against extreme environments and operational anomalies. The electronics are designed to survive the thermal, vibration, shock and radiation environment of launch and orbit, while providing a design life in excess of 10 years on-orbit. A number of our current generation high reliability radiation-hardened electronics units are in various stages of integration on several space flight payloads. This paper describes the features and performance of our latest flight electronics designed for the pulse-tube cryocooler that is the pre-cooler for a closed cycle Joule-Thomson cooler providing 6K cooling for the James Webb Space Telescope (JWST) Mid Infra-Red Instrument (MIRI). The electronics is capable of highly accurate temperature control over the temperature range from 4K to 15K. Self-induced vibration is controlled to low levels on all harmonics up to the 16th. A unique active power filter controls peak-to-peak reflected ripple current on the primary power bus to a very low level. The 9 kg unit is capable of delivering 360W continuous power to NGAS's 3-stage pulse-tube High-Capacity Cryocooler (HCC).

  18. A 1 T, 0.33 m bore superconducting magnet operating with cryocoolers at 12 K

    NARCIS (Netherlands)

    Laan, van der M.T.G.; Tax, R.B.; Kate, ten H.H.J.; Klundert, van de L.J.M.

    1992-01-01

    The application of small cryocoolers to cooling a superconducting magnet at 12 K has important advantages, especially for small and medium-size magnets. Simple construction and a helium-free magnet system were obtained. The demonstration magnet developed is a six-coil system with a volume of 75 L an

  19. High-frequency operation and miniaturization aspects of pulse-tube cryocoolers

    NARCIS (Netherlands)

    Vanapalli, Srinivas

    2008-01-01

    Cryocoolers are small refrigerators capable of achieving useful refrigeration below 120 K. Recent developments in the field of high Tc superconductors spawned a wide range of applications such as terahertz sensors, SQUIDS, low noise amplifiers, filters for microwave applications and many more. These

  20. Hampson’s type cryocoolers with distributed Joule-Thomson effect for mixed refrigerants closed cycle

    Science.gov (United States)

    Maytal, Ben-Zion

    2014-05-01

    Most previous studies on Joule-Thomson cryocoolers of mixed refrigerants in a closed cycle focus on the Linde kind recuperator. The present study focuses on four constructions of Hampson’s kind miniature Joule-Thomson cryocoolers based on finned capillary tubes. The frictional pressure drop along the tubes plays the role of distributed Joule-Thomson expansion so that an additional orifice or any throttle at the cold end is eliminated. The high pressure tube is a throttle and a channel of recuperation at the same time. These coolers are tested within two closed cycle systems of different compressors and different compositions of mixed coolants. All tests were driven by the same level of discharge pressure (2.9 MPa) while the associated suction pressures and the associated reached temperatures are dependent on each particular cryocooler and on the closed cycle system. The mixture of higher specific cooling capacity cannot reach temperatures below 80 K when driven by the smaller compressor. The other mixture of lower specific cooling capacity driven by the larger compressor reaches lower temperatures. The examined parameters are the cooldown period and the reachable temperatures by each cryocooler.

  1. Adaptive periodic disturbance cancellation in a set-up of two cryocoolers

    NARCIS (Netherlands)

    Rijpma, A.P.; Verberne, J.F.C.; Wtbreuk, E.H.R.; Bruins, P.C.; Brake, ter H.J.M.

    1998-01-01

    The work presented describes adaptive periodic disturbance cancellation as applied to the vibration of two cryocoolers. The coolers are driven by linear motors. The periodic input signal necessary to reduce the disturbance is calculated by vibration measurements using the systems frequency response.

  2. Affects of Mechanical Milling and Metal Oxide Additives on Sorption Kinetics of 1:1 LiNH2/MgH2 Mixture

    Directory of Open Access Journals (Sweden)

    Donald L. Anton

    2011-05-01

    Full Text Available The destabilized complex hydride system composed of LiNH2:MgH2 (1:1 molar ratio is one of the leading candidates of hydrogen storage with a reversible hydrogen storage capacity of 8.1 wt%. A low sorption enthalpy of ~32 kJ/mole H2 was first predicted by Alapati et al. utilizing first principle density function theory (DFT calculations and has been subsequently confirmed empirically by Lu et al. through differential thermal analysis (DTA. This enthalpy suggests that favorable sorption kinetics should be obtainable at temperatures in the range of 160 °C to 200 °C. Preliminary experiments reported in the literature indicate that sorption kinetics are substantially lower than expected in this temperature range despite favorable thermodynamics. Systematic isothermal and isobaric sorption experiments were performed using a Sievert’s apparatus to form a baseline data set by which to compare kinetic results over the pressure and temperature range anticipated for use of this material as a hydrogen storage media. Various material preparation methods and compositional modifications were performed in attempts to increase the kinetics while lowering the sorption temperatures. This paper outlines the results of these systematic tests and describes a number of beneficial additions which influence kinetics as well as NH3 formation.

  3. AFFECTS OF MECHANICAL MILLING AND METAL OXIDE ADDITIVES ON SORPTION KINETICS OF 1:1 LiNH2/MgH2 MIXTURE

    Energy Technology Data Exchange (ETDEWEB)

    Erdy, C.; Anton, D.; Gray, J.

    2010-12-08

    The destabilized complex hydride system composed of LiNH{sub 2}:MgH{sub 2} (1:1 molar ratio) is one of the leading candidates of hydrogen storage with a reversible hydrogen storage capacity of 8.1 wt%. A low sorption enthalpy of {approx}32 kJ/mole H{sub 2} was first predicted by Alapati et al. utilizing first principle density function theory (DFT) calculations and has been subsequently confirmed empirically by Lu et al. through differential thermal analysis (DTA). This enthalpy suggests that favorable sorption kinetics should be obtainable at temperatures in the range of 160 C to 200 C. Preliminary experiments reported in the literature indicate that sorption kinetics are substantially lower than expected in this temperature range despite favorable thermodynamics. Systematic isothermal and isobaric sorption experiments were performed using a Sievert's apparatus to form a baseline data set by which to compare kinetic results over the pressure and temperature range anticipated for use of this material as a hydrogen storage media. Various material preparation methods and compositional modifications were performed in attempts to increase the kinetics while lowering the sorption temperatures. This paper outlines the results of these systematic tests and describes a number of beneficial additions which influence kinetics as well as NH{sub 3} formation.

  4. Method of making crack-free zirconium hydride

    Science.gov (United States)

    Sullivan, Richard W.

    1980-01-01

    Crack-free hydrides of zirconium and zirconium-uranium alloys are produced by alloying the zirconium or zirconium-uranium alloy with beryllium, or nickel, or beryllium and scandium, or nickel and scandium, or beryllium and nickel, or beryllium, nickel and scandium and thereafter hydriding.

  5. Creating nanoshell on the surface of titanium hydride bead

    Directory of Open Access Journals (Sweden)

    PAVLENKO Vyacheslav Ivanovich

    2016-12-01

    Full Text Available The article presents data on the modification of titanium hydride bead by creating titanium nanoshell on its surface by ion-plasma vacuum magnetron sputtering. To apply titanium nanoshell on the titanium hydride bead vacuum coating plant of multifunctional nanocomposite coatings QVADRA 500 located in the center of high technology was used. Analysis of the micrographs of the original surface of titanium hydride bead showed that the microstructure of the surface is flat, smooth, in addition the analysis of the microstructure of material surface showed the presence of small porosity, roughness, mainly cavities, as well as shallow longitudinal cracks. The presence of oxide film in titanium hydride prevents the free release of hydrogen and fills some micro-cracks on the surface. Differential thermal analysis of both samples was conducted to determine the thermal stability of the initial titanium hydride bead and bead with applied titanium nanoshell. Hydrogen thermal desorption spectra of the samples of the initial titanium hydride bead and bead with applied titanium nanoshell show different thermal stability of compared materials in the temperature range from 550 to 860о C. Titanium nanoshells applied in this way allows increasing the heat resistance of titanium hydride bead – the temperature of starting decomposition is 695о C and temperature when decomposition finishes is more than 1000о C. Modified in this way titanium hydride bead can be used as a filler in the radiation protective materials used in the construction or upgrading biological protection of nuclear power plants.

  6. Hydrogen storage in the form of metal hydrides

    Science.gov (United States)

    Zwanziger, M. G.; Santana, C. C.; Santos, S. C.

    1984-01-01

    Reversible reactions between hydrogen and such materials as iron/titanium and magnesium/ nickel alloy may provide a means for storing hydrogen fuel. A demonstration model of an iron/titanium hydride storage bed is described. Hydrogen from the hydride storage bed powers a converted gasoline electric generator.

  7. Electrochemical and Optical Properties of Magnesium-Alloy Hydrides Reviewed

    Directory of Open Access Journals (Sweden)

    Thirugnasambandam G. Manivasagam

    2012-10-01

    Full Text Available As potential hydrogen storage media, magnesium based hydrides have been systematically studied in order to improve reversibility, storage capacity, kinetics and thermodynamics. The present article deals with the electrochemical and optical properties of Mg alloy hydrides. Electrochemical hydrogenation, compared to conventional gas phase hydrogen loading, provides precise control with only moderate reaction conditions. Interestingly, the alloy composition determines the crystallographic nature of the metal-hydride: a structural change is induced from rutile to fluorite at 80 at.% of Mg in Mg-TM alloy, with ensuing improved hydrogen mobility and storage capacity. So far, 6 wt.% (equivalent to 1600 mAh/g of reversibly stored hydrogen in MgyTM(1-yHx (TM: Sc, Ti has been reported. Thin film forms of these metal-hydrides reveal interesting electrochromic properties as a function of hydrogen content. Optical switching occurs during (dehydrogenation between the reflective metal and the transparent metal hydride states. The chronological sequence of the optical improvements in optically active metal hydrides starts with the rare earth systems (YHx, followed by Mg rare earth alloy hydrides (MgyGd(1-yHx and concludes with Mg transition metal hydrides (MgyTM(1-yHx. In-situ optical characterization of gradient thin films during (dehydrogenation, denoted as hydrogenography, enables the monitoring of alloy composition gradients simultaneously.

  8. High energy density battery based on complex hydrides

    Science.gov (United States)

    Zidan, Ragaiy

    2016-04-26

    A battery and process of operating a battery system is provided using high hydrogen capacity complex hydrides in an organic non-aqueous solvent that allows the transport of hydride ions such as AlH.sub.4.sup.- and metal ions during respective discharging and charging steps.

  9. High energy density battery based on complex hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Zidan, Ragaiy

    2016-04-26

    A battery and process of operating a battery system is provided using high hydrogen capacity complex hydrides in an organic non-aqueous solvent that allows the transport of hydride ions such as AlH.sub.4.sup.- and metal ions during respective discharging and charging steps.

  10. Synthesis, characterization and properties of some organozinc hydride complexes

    NARCIS (Netherlands)

    Koning, A.J. de; Boersma, J.; Kerk, G.J.M. van der

    1980-01-01

    The synthesis and characterization of the monopyridine complexes of ethylzinc hydride and phenylzinc hydride are described. On treatment with TMED these complexes are converted into R2Zn3H4. TMED species through a combination of ligand-exchange and disproportionation. The formation of organozinc hyd

  11. Hydride morphology and striation formation during delayed hydride cracking in Zr-2.5% Nb

    Energy Technology Data Exchange (ETDEWEB)

    Shek, G.K. [Ontario Hydro Technol., Ont. (Canada). Mater. Technol. Unit; Jovanovic, M.T. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mining, Metallurgical and Petroleum Engineering; Seahra, H. [Ontario Hydro Technol., Ont. (Canada). Mater. Technol. Unit; Ma, Y. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mining, Metallurgical and Petroleum Engineering; Li, D. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mining, Metallurgical and Petroleum Engineering; Eadie, R.L. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mining, Metallurgical and Petroleum Engineering

    1996-08-01

    These experiments were designed to study hydride formation at the crack tip, acoustic emission (AE), potential drop (PD) and striation formation during DHC (delayed hydride cracking) in Zr-2.5% Nb. The test material was taken from an especially extruded pressure tube, which showed similar strength properties to normal pressure tube material but somewhat coarser microstructure. In testing at K{sub I} below 12 MPa {radical}m at both 200 and 250 C very large striations (>40 {mu}m at 200 and >50 {mu}m at 250 C) were produced. In simultaneous monitoring with acoustic emission and potential drop, both AE and PD jumps were shown to be monolithic. The number of striations on the fracture surface corresponded to the number of monolithic AE/PD jumps. Tapered shaped hydrides with the thick end adjacent to the crack tip were observed. These hydrides grew in size during the incubation period until they reached the striation length and then fractured monolithically. However, when K{sub I} was increased beyond about 12 MPa {radical}m for these same specimens, the striation spacing decreased below 30 {mu}m, the monolithic jumping dissolved into more continuous changes in signals, although the smaller striations were still visible on the fracture surface. (orig.).

  12. Hydride morphology and striation formation during delayed hydride cracking in Zr-2.5% Nb

    Science.gov (United States)

    Shek, G. K.; Jovanoviċ, M. T.; Seahra, H.; Ma, Y.; Li, D.; Eadie, R. L.

    1996-08-01

    These experiments were designed to study hydride formation at the crack tip, acoustic emission (AE), potential drop (PD) and striation formation during DHC (delayed hydride cracking) in Zr-2.5% Nb. The test material was taken from an especially extrude pressure tube, which showed similar strength properties to normal pressure tube material but somewhat coarser microstructure. In testing at KI below 12 MPa √m at both 200 and 250°C very large striations (> 40 μ at 200 and >50 μm at 250°C) were produced. In simultaneous monitoring with acoustic emission and potential drop, both AE and PD jumps were shown to be monolithic. The number of striations on the fracture surface corresponded to the number of monolithic AE/PD jumps. Tapered shaped hydrides with the thick end adjacent to the crack tip were observed. These hydrides grew in size during the incubation period until they reached the striation length and then fractured monolithically. However, when KI was increased beyond about 12 MPa √m for these same specimens, the striation spacing decreased below 30 μ, the monolithic jumping dissolved into more continuous changes in signals, although the smaller striations were still visible on the fracture surface.

  13. High ramp rate thermogravimetric analysis of zirconium(II) hydride and titanium(II) hydride

    Energy Technology Data Exchange (ETDEWEB)

    Licavoli, Joseph J., E-mail: jjlicavo@mtu.edu; Sanders, Paul G., E-mail: sanders@mtu.edu

    2015-09-20

    Highlights: • A unique arc image device has been proposed for high ramp rate thermogravimetry. • Powder oxidation influences decomposition kinetics at temperatures below 933 K. • Particle size has a negligible effect on TiH{sub 2} decomposition behavior. • Improvements to the device are required to conduct accurate kinetic analysis. - Abstract: Zirconium and titanium hydride are utilized in liquid phase metal foam processing techniques. This application results in immediate exposure to molten metal and almost immediate decomposition at high temperatures. Most decomposition characterization techniques utilize slow heating rates and are unable to capture the decomposition behavior of hydrides under foam processing conditions. In order to address this issue a specialized high ramp rate thermogravimetric analyzer was created from a xenon arc image refiner. In addition to thermogravimetry, complimentary techniques including X-ray diffraction and scanning electron microscopy were used to characterize hydride decomposition and compare the results to literature. Hydrides were partially oxidized and separated into particles size ranges to evaluate the influence of these factors on decomposition. Oxidizing treatments were found to decrease decomposition rate only at temperatures below 933 K (660 °C) while particle size effects appeared to be negligible. Several improvements to the unique TGA apparatus presented in the current work are suggested to allow reliable kinetic modeling and analysis.

  14. ORNL Interim Progress Report on Hydride Reorientation CIRFT Tests

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yan, Yong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Hong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-10-28

    A systematic study of H. B. Robinson (HBR) high burnup spent nuclear fuel (SNF) vibration integrity was performed in Phase I project under simulated transportation environments, using the Cyclic Integrated Reversible-Bending Fatigue Tester (CIRFT) hot cell testing technology developed at Oak Ridge National Laboratory in 2013–14. The data analysis on the as-irradiated HBR SNF rods demonstrated that the load amplitude is the dominant factor that controls the fatigue life of bending rods. However, previous studies have shown that the hydrogen content and hydride morphology has an important effect on zirconium alloy mechanical properties. To address the effect of radial hydrides in SNF rods, in Phase II a test procedure was developed to simulate the effects of elevated temperatures, pressures, and stresses during transfer-drying operations. Pressurized and sealed fuel segments were heated to the target temperature for a preset hold time and slow-cooled at a controlled rate. The procedure was applied to both non-irradiated/prehydrided and high-burnup Zircaloy-4 fueled cladding segments using the Nuclear Regulatory Commission-recommended 400°C maximum temperature limit at various cooling rates. Before testing high-burnup cladding, four out-of-cell tests were conducted to optimize the hydride reorientation (R) test condition with pre-hydride Zircaloy-4 cladding, which has the same geometry as the high burnup fuel samples. Test HR-HBR#1 was conducted at the maximum hoop stress of 145 MPa, at a 400°C maximum temperature and a 5°C/h cooling rate. On the other hand, thermal cycling was performed for tests HR-HBR#2, HR-HBR#3, and HR-HBR#4 to generate more radial hydrides. It is clear that thermal cycling increases the ratio of the radial hydride to circumferential hydrides. The internal pressure also has a significant effect on the radial hydride morphology. This report describes a procedure and experimental results of the four out-of-cell hydride reorientation tests of

  15. Growth and decomposition of Lithium and Lithium hydride on Nickel

    DEFF Research Database (Denmark)

    Engbæk, Jakob; Nielsen, Gunver; Nielsen, Jane Hvolbæk

    2006-01-01

    In this paper we have investigated the deposition, structure and decomposition of lithium and lithium-hydride films on a nickel substrate. Using surface sensitive techniques it was possible to quantify the deposited Li amount, and to optimize the deposition procedure for synthesizing lithium......-hydride films. By only making thin films of LiH it is possible to study the stability of these hydride layers and compare it directly with the stability of pure Li without having any transport phenomena or adsorbed oxygen to obscure the results. The desorption of metallic lithium takes place at a lower...... temperature than the decomposition of the lithium-hydride, confirming the high stability and sintering problems of lithium-hydride making the storage potential a challenge. (c) 2006 Elsevier B.V. All rights reserved....

  16. Helium trapping at erbium oxide precipitates in erbium hydride

    Energy Technology Data Exchange (ETDEWEB)

    Foiles, Stephen M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Battaile, Corbett Chandler [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-02-01

    The formation of He bubbles in erbium tritides is a significant process in the aging of these materials. Due to the long-standing uncertainty about the initial nucleation process of these bubbles, there is interest in mechanisms that can lead to the localization of He in erbium hydrides. Previous work has been unable to identify nucleation sites in homogeneous erbium hydride. This work builds on the experimental observation that erbium hydrides have nano- scale erbium oxide precipitates due to the high thermodynamic stability of erbium oxide and the ubiquitous presence of oxygen during materials processing. Fundamental DFT calculations indicate that the He is energetically favored in the oxide relative to the bulk hydride. Activation energies for the motion of He in the oxide and at the oxide-hydride interface indicate that trapping is kinetically feasible. A simple kinetic Monte Carlo model is developed that demonstrates the degree of trapping of He as a function of temperature and oxide fraction.

  17. Photochromism of rare-earth metal-oxy-hydrides

    Science.gov (United States)

    Nafezarefi, F.; Schreuders, H.; Dam, B.; Cornelius, S.

    2017-09-01

    Recently, thin films of yttrium oxy-hydride (YOxHy) were reported to show an unusual color-neutral photochromic effect promising for application in smart windows. Our present work demonstrates that also oxy-hydrides based on Gd, Dy, and Er have photochromic properties and crystal structures similar to YOxHy. Compared to YOxHy, the optical bandgaps of the lanthanide based oxy-hydrides are smaller while photochromic contrast and kinetics show large variation among different cations. Based on these findings, we propose that cation alloying is a viable pathway to tailor the photochromic properties of oxy-hydride materials. Furthermore, we predict that the oxy-hydrides of the other lanthanides are also potentially photochromic.

  18. Metal hydrides for concentrating solar thermal power energy storage

    Science.gov (United States)

    Sheppard, D. A.; Paskevicius, M.; Humphries, T. D.; Felderhoff, M.; Capurso, G.; Bellosta von Colbe, J.; Dornheim, M.; Klassen, T.; Ward, P. A.; Teprovich, J. A.; Corgnale, C.; Zidan, R.; Grant, D. M.; Buckley, C. E.

    2016-04-01

    The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost of concentrating solar thermal power. We focus on the underlying technology that allows metal hydrides to function as thermal energy storage (TES) systems and highlight the current state-of-the-art materials that can operate at temperatures as low as room temperature and as high as 1100 °C. The potential of metal hydrides for thermal storage is explored, while current knowledge gaps about hydride properties, such as hydride thermodynamics, intrinsic kinetics and cyclic stability, are identified. The engineering challenges associated with utilising metal hydrides for high-temperature TES are also addressed.

  19. Thermal properties of a large-bore cryocooled 10 T superconducting magnet for a hybrid magnet

    Energy Technology Data Exchange (ETDEWEB)

    Ishizuka, M., E-mail: Mas_Ishizuka@shi.co.j [Graduate School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 (Japan); Research and Development Center, Sumitomo Heavy Industries, Ltd., 19 Natsushima-chou, Yokosuka, Kanagawa 237-8555 (Japan); Hamajima, T. [Graduate School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 (Japan); Itou, T. [Ehime Works, Sumitomo Heavy Industries, Ltd., 5-2 Soubiraki-cho, Niihama, Ehime 792-8588 (Japan); Sakuraba, J. [Research and Development Center, Sumitomo Heavy Industries, Ltd., 19 Natsushima-chou, Yokosuka, Kanagawa 237-8555 (Japan); Nishijima, G.; Awaji, S.; Watanabe, K. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2010-11-01

    A cryocooled 10 T superconducting magnet with a 360 mm room temperature bore has been developed for a hybrid magnet. The superconducting magnet cooled by four Gifford-McMahon cryocoolers has been designed to generate a magnetic field of 10 T. Since superconducting wires composed of coils were subjected to large hoop stress over 150 MPa and Nb{sub 3}Sn superconducting wires particularly showed a low mechanical strength due to those brittle property, Nb{sub 3}Sn wires strengthened by NbTi-filaments were developed for the cryocooled superconducting magnet. We have already reported that the hybrid magnet could generate the resultant magnetic field of 27.5 T by adding 8.5 T from the superconducting magnet and 19 T from a water-cooled Bitter resistive magnet, after the water-cooled resistive magnet was inserted into the 360 mm room temperature bore of the cryocooled superconducting magnet. When the hybrid magnet generated the field of 27.5 T, it achieved the high magnetic-force field (B x {partial_derivative}Bz/{partial_derivative}z) of 4500 T{sup 2}/m, which was useful for magneto-science in high fields such as materials levitation research. In this paper, we particularly focus on the cause that the cryocooled superconducting magnet was limited to generate the designed magnetic field of 10 T in the hybrid magnet operation. As a result, it was found that there existed mainly two causes as the limitation of the magnetic field generation. One was a decrease of thermal conductive passes due to exfoliation from the coil bobbin of the cooling flange. The other was large AC loss due to both a thick Nb{sub 3}Sn layer and its large diameter formed on Nb-barrier component in Nb{sub 3}Sn wires.

  20. VIRTIS on board Rosetta: cryocoolers usage analysis in support of Comet phases observations

    Science.gov (United States)

    Giuppi, Stefano; Politi, Romolo; Capria, Maria Teresa; Piccioni, Giuseppe; De Sanctis, Maria Cristina; Erard, Stéphane; Tosi, Federico; Capaccioni, Fabrizio; Filacchione, Gianrico

    Rosetta is a planetary cornerstone mission of the European Space Agency (ESA). It is devoted to the study of minor bodies of our solar system and it will be the first mission ever to land on a comet (the Jupiter-family comet 67P/Churyumov-Gerasimenko). VIRTIS-M is a sophisticated imaging spectrometer that combines two data channels in one compact instrument, respectively for the visible and the infrared range (0.25-5.0 μm). VIRTIS-H is devoted to infrared spectroscopy (2.5-5.0 μm) with high spectral resolution. Since the satellite will be inside the tail of the comet during one of the most important phases of the mission, it would not be appropriate to use a passive cooling system, due to the high flux of contaminants on the radiator. Therefore the IR sensors are cooled by two Stirling cycle cryocoolers. This paper focuses on the usage of VIRTIS cryocoolers from the beginning of the Rosetta mission till spacecraft hibernation in order to optimize their usage. After a description of the cryocooler used in the mission, a detailed information about time usage and power consumption is provided. On the basis of previous experiences with this kind of cryocoolers it has been made an estimation of the remaining working life of the VIRTIS coolers operating in Rosetta mission. Moreover an estimation of the minimum time between a cryocooler switch off and on again has been carried out in order to preserve the coolers working life.

  1. Results of NDE Technique Evaluation of Clad Hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Kunerth, Dennis C. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-09-01

    This report fulfills the M4 milestone, M4FT-14IN0805023, Results of NDE Technique Evaluation of Clad Hydrides, under Work Package Number FT-14IN080502. During service, zirconium alloy fuel cladding will degrade via corrosion/oxidation. Hydrogen, a byproduct of the oxidation process, will be absorbed into the cladding and eventually form hydrides due to low hydrogen solubility limits. The hydride phase is detrimental to the mechanical properties of the cladding and therefore it is important to be able to detect and characterize the presence of this constituent within the cladding. Presently, hydrides are evaluated using destructive examination. If nondestructive evaluation techniques can be used to detect and characterize the hydrides, the potential exists to significantly increase test sample coverage while reducing evaluation time and cost. To demonstrate the viability this approach, an initial evaluation of eddy current and ultrasonic techniques were performed to demonstrate the basic ability to these techniques to detect hydrides or their effects on the microstructure. Conventional continuous wave eddy current techniques were applied to zirconium based cladding test samples thermally processed with hydrogen gas to promote the absorption of hydrogen and subsequent formation of hydrides. The results of the evaluation demonstrate that eddy current inspection approaches have the potential to detect both the physical damage induced by hydrides, e.g. blisters and cracking, as well as the combined effects of absorbed hydrogen and hydride precipitates on the electrical properties of the zirconium alloy. Similarly, measurements of ultrasonic wave velocities indicate changes in the elastic properties resulting from the combined effects of absorbed hydrogen and hydride precipitates as well as changes in geometry in regions of severe degradation. However, for both approaches, the signal responses intended to make the desired measurement incorporate a number of contributing

  2. Nanoindentation measurements of the mechanical properties of zirconium matrix and hydrides in unirradiated pre-hydrided nuclear fuel cladding

    Science.gov (United States)

    Rico, A.; Martin-Rengel, M. A.; Ruiz-Hervias, J.; Rodriguez, J.; Gomez-Sanchez, F. J.

    2014-09-01

    It is well known that the mechanical properties of the nuclear fuel cladding may be affected by the presence of hydrides. The average mechanical properties of hydrided cladding have been extensively investigated from a macroscopic point of view. In addition, the mechanical and fracture properties of bulk hydride samples fabricated from zirconium plates have also been reported. In this paper, Young's modulus, hardness and yield stress are measured for each phase, namely zirconium hydrides and matrix, of pre-hydrided nuclear fuel cladding. To this end, nanoindentation tests were performed on ZIRLO samples in as-received state, on a hydride blister and in samples with 150 and 1200 ppm of hydrogen homogeneously distributed along the hoop direction of the cladding. The results show that the measured mechanical properties of the zirconium hydrides and ZIRLO matrix (Young's modulus, hardness and yield stress) are rather similar. From the experimental data, the hydride volume fraction in the cladding samples with 150 and 1200 ppm was estimated and the average mechanical properties were calculated by means of the rule of mixtures. These values were compared with those obtained from ring compression tests. Good agreement between the results obtained by both methods was found.

  3. Nanoindentation measurements of the mechanical properties of zirconium matrix and hydrides in unirradiated pre-hydrided nuclear fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Rico, A., E-mail: alvaro.rico@urjc.es [DIMME, Departamento de Tecnología Mecánica, Universidad Rey Juan Carlos, c/Tulipán s/n, E-28933 Móstoles, Madrid (Spain); Martin-Rengel, M.A., E-mail: mamartin@mater.upm.es [Departamento de Ciencia de los Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos, Profesor Aranguren SN, E-28040 Madrid (Spain); Ruiz-Hervias, J., E-mail: jesus.ruiz@upm.es [Departamento de Ciencia de los Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos, Profesor Aranguren SN, E-28040 Madrid (Spain); Rodriguez, J. [DIMME, Departamento de Tecnología Mecánica, Universidad Rey Juan Carlos, c/Tulipán s/n, E-28933 Móstoles, Madrid (Spain); Gomez-Sanchez, F.J., E-mail: javier.gomez@amsimulation.com [Advanced Material Simulation, S.L, Madrid (Spain)

    2014-09-15

    It is well known that the mechanical properties of the nuclear fuel cladding may be affected by the presence of hydrides. The average mechanical properties of hydrided cladding have been extensively investigated from a macroscopic point of view. In addition, the mechanical and fracture properties of bulk hydride samples fabricated from zirconium plates have also been reported. In this paper, Young’s modulus, hardness and yield stress are measured for each phase, namely zirconium hydrides and matrix, of pre-hydrided nuclear fuel cladding. To this end, nanoindentation tests were performed on ZIRLO samples in as-received state, on a hydride blister and in samples with 150 and 1200 ppm of hydrogen homogeneously distributed along the hoop direction of the cladding. The results show that the measured mechanical properties of the zirconium hydrides and ZIRLO matrix (Young’s modulus, hardness and yield stress) are rather similar. From the experimental data, the hydride volume fraction in the cladding samples with 150 and 1200 ppm was estimated and the average mechanical properties were calculated by means of the rule of mixtures. These values were compared with those obtained from ring compression tests. Good agreement between the results obtained by both methods was found.

  4. Sorption equilibria of ethanol on cork.

    Science.gov (United States)

    Lequin, Sonia; Chassagne, David; Karbowiak, Thomas; Bellat, Jean-Pierre

    2013-06-01

    We report here for the first time a thermodynamic study of gaseous ethanol sorption on raw cork powder and plate. Our study aims at a better understanding of the reactivity of this material when used as a stopper under enological conditions, thus in close contact with a hydroethanolic solution, wine. Sorption−desorption isotherms were accurately measured by thermogravimetry at 298 K in a large range of relative pressures. Sorption enthalpies were determined by calorimetry as a function of loading. Sorption−desorption isotherms exhibit a hysteresis loop probably due to the swelling of the material and the absorption of ethanol. Surprisingly, the sorption enthalpy of ethanol becomes lower than the liquefaction enthalpy as the filling increases. This result could be attributed to the swelling of the material, which would generate endothermic effects. Sorption of SO₂ on cork containing ethanol was also studied. When the ethanol content in cork is 2 wt %, the amount of SO₂ sorbed is divided by 2. Thus, ethanol does not enhance the sorption rate for SO₂ but, on the contrary, decreases the SO₂ sorption activity onto cork, probably because of competitive sorption mechanisms.

  5. Sorption of melanoidin onto surfactant modified zeolite

    Directory of Open Access Journals (Sweden)

    Onyango Maurice S.

    2011-01-01

    Full Text Available Melanoidin is responsible for the dark brown colour of distillery wastewater. Discharge of coloured wastewater has a major environmental impact on the biota of the receiving water body. Consequently, this study explores the removal of melanodin from aqueous solution. The equilibrium, kinetics and thermodynamics of melanoidin sorption are studied by varying initial solution pH, initial concentration, adsorbent dose and temperature. Kinetically, the melanoidin removal from solution by a surfactant modified zeolite is rapid and the amount adsorbed is dependent on pH, initial concentration, adsorbent dose and temperature. The equilibrium sorption data are fitted to the Freundlich and Langmuir models while the sorption, kinetics is described by the Ho pseudo-second order and Elovich models. The thermodynamic analysis indicates that the sorption is spontaneous and endothermic in nature. The FTIR spectra analyses show no new peaks or shift in peaks after sorption indicating that the melanoidin sorption may have occurred by a physical process. The results from desorption studies showed that melanoidin eluted back easily to the solution using distilled water which corroborates the physical sorption mechanism.

  6. Nanostructured Magnesium Hydride for Reversible Hydrogen Storage

    Science.gov (United States)

    de Rango, P.; Chaise, A.; Fruchart, D.; Miraglia, S.; Marty, Ph.

    2013-05-01

    The aim of this work was to develop suitable materials to store hydrogen in a solid state. A systematic investigation of the co-milling process of magnesium hydride with a transition metal was undertaken in order to produce nanostructured and highly reactive powders. The initiating role of the transition metal was evidenced by in situ neutron diffraction experiments. High performances in terms of thermal and mechanical behavior were achieved introducing expanded graphite and compacting the mixture to form composite materials. Absorption and desorption kinetics have been measured versus temperature and H2 pressure.

  7. Lithium hydride - A space age shielding material

    Science.gov (United States)

    Welch, F. H.

    1974-01-01

    Men and materials performing in the environment of an operating nuclear reactor require shielding from the escaping neutron particles and gamma rays. For efficient shielding from gamma rays, dense, high atomic number elements such as iron, lead, or tungsten are required, whereas light, low atomic number elements such as hydrogen, lithium, or beryllium are required for efficient neutron shielding. The use of lithium hydride (LiH) as a highly efficient neutron-shielding material is considered. It contains, combined into a single, stable compound, two of the elements most effective in attenuating and absorbing neutrons.

  8. Highly Concentrated Palladium Hydrides/Deuterides; Theory

    Energy Technology Data Exchange (ETDEWEB)

    Papaconstantopoulos, Dimitrios

    2013-11-26

    Accomplishments are reported in these areas: tight-binding molecular dynamics study of palladium; First-principles calculations and tight-binding molecular dynamics simulations of the palladium-hydrogen system; tight-binding studies of bulk properties and hydrogen vacancies in KBH{sub 4}; tight-binding study of boron structures; development of angular dependent potentials for Pd-H; and density functional and tight-binding calculations for the light-hydrides NaAlH4 and NaBH4

  9. Development of nickel-metal hydride cell

    Science.gov (United States)

    Kuwajima, Saburo; Kamimori, Nolimits; Nakatani, Kensuke; Yano, Yoshiaki

    1993-01-01

    National Space Development Agency of Japan (NASDA) has conducted the research and development (R&D) of battery cells for space use. A new R&D program about a Nickel-Metal Hydride (Ni-MH) cell for space use from this year, based on good results in evaluations of commercial Ni-MH cells in Tsukuba Space Center (TKSC), was started. The results of those commercial Ni-MH cell's evaluations and recent status about the development of Ni-MH cells for space use are described.

  10. Sorption of methylxanthines by different sorbents

    Science.gov (United States)

    Dmitrienko, S. G.; Andreeva, E. Yu.; Tolmacheva, V. V.; Terent'eva, E. A.

    2013-05-01

    Sorption of caffeine, theophylline, theobromine, diprophylline, and pentoxyphylline on different sorbents (supercross-linked polystyrene, surface-modified copolymer of styrene and divinylbenzene Strata-X, and carbon nanomaterials Taunit and Diasorb-100-C16T) was studied in a static mode in an effort to find new sorbents suitable for sorption isolation and concentration of methylxanthines. The peculiarities of sorption of methylxanthines were explained in relation to the solution acidity, the nature of the sorbates and their concentration, the nature of the solvent, and the structural characteristics of the sorbents.

  11. Effect of operating frequency and phase angle on performance of Alpha Stirling cryocooler driven by a novel compact mechanism

    Science.gov (United States)

    Sant, K. D.; Bapat, S. L.

    2015-12-01

    Amongst the mechanical cryocoolers in use, Stirling cycle cryocoolers exhibit the desirable features such as high efficiency, low specific power consumption, small size and mass and large mean time before failure. Stirling cycle cryocooler of Alpha configuration exhibits better theoretical performance as compared to Gamma. However, the theory could not be put into practice due to unavailability of compatible drive mechanism for Alpha cryocooler providing large stroke to diameter ratio. The concept of novel compact drive mechanism can be made functional to operate miniature Alpha Stirling cryocoolers. It allows the use of multicylinder system while converting rotary motion to reciprocating. This permits the drive mechanism to be employed for driving different configurations of Stirling cryocooler simultaneously. This drive is capable of providing large stroke to diameter ratio compared to other drive mechanisms generally in use for the purpose. A stroke to diameter ratio of three is chosen in the present work and the drive dimensions are calculated for four piston-cylinder arrangements with 90° phase difference between adjacent arrangements providing two Alpha Stirling cryocoolers working simultaneously. It has to be noted that the coolers operate at half the frequency of the motor used. As the two coolers operate at phase difference of 180°, during compression stroke of one unit, the suction stroke occurs for the other unit. Due to power output of second unit, the combined peak torque requirement falls by 26.81% below the peak torque needed when one unit is operated separately. This allows for use of a comparatively lower torque motor. The practicability of the drive ensuring smooth operation of the system is decided based on comparison between torque availability from the motor and torque requirement of the complete unit. The second order method of cyclic (or thermodynamic) analysis provides a simple computational procedure useful for the design of Stirling

  12. Sorption Refrigeration / Heat Pump Cycles

    Science.gov (United States)

    Saha, Bidyut Baran; Alam, K. C. Amanul; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

    Over the past few decades there have been considerable efforts to use adsorption (solid/vapor) for cooling and heat pump applications, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). Up to now, only the desiccant evaporative cooling system of the open type has achieved commercial use, predominantly in the United States. Closed-type adsorption refrigeration and heat pump systems are rarely seen in the market, or are still in the laboratory testing stage. Promising recent development have been made in Japan for the use of porous metal hydrides and composite adsorbents. In this paper, a short description of adsorption theories along with an overview of present status and future development trends of thermally powered adsorption refrigeration cycles are outlined putting emphasis on experimental achievements. This paper also addressed some advanced absorption cycles having relatively higher COP, and also summarizes fundamental concepts of GAX cycles and various GAX cycles developed for heat pump applications.

  13. NATO Advanced Study Institute on Metal Hydrides

    CERN Document Server

    1981-01-01

    In the last five years, the study of metal hydrides has ex­ panded enormously due to the potential technological importance of this class of materials in hydrogen based energy conversion schemes. The scope of this activity has been worldwide among the industrially advanced nations. There has been a consensus among researchers in both fundamental and applied areas that a more basic understanding of the properties of metal/hydrogen syster;,s is required in order to provide a rational basis for the selection of materials for specific applications. The current worldwide need for and interest in research in metal hydrides indicated the timeliness of an Advanced Study Insti­ tute to provide an in-depth view of the field for those active in its various aspects. The inclusion of speakers from non-NATO coun­ tries provided the opportunity for cross-fertilization of ideas for future research. While the emphasis of the Institute was on basic properties, there was a conscious effort to stimulate interest in the applic...

  14. Molecular rare-earth-metal hydrides in non-cyclopentadienyl environments.

    Science.gov (United States)

    Fegler, Waldemar; Venugopal, Ajay; Kramer, Mathias; Okuda, Jun

    2015-02-02

    Molecular hydrides of the rare-earth metals play an important role as homogeneous catalysts and as counterparts of solid-state interstitial hydrides. Structurally well-characterized non-metallocene-type hydride complexes allow the study of elementary reactions that occur at rare-earth-metal centers and of catalytic reactions involving bonds between rare-earth metals and hydrides. In addition to neutral hydrides, cationic derivatives have now become available.

  15. Development of GM cryocooler separate type liquid-helium-free 3He-4He dilution refrigerator system

    Science.gov (United States)

    Yamanaka, Y.; Ito, T.; Umeno, T.; Suzuki, Y.; Yoshida, S.; Kamioka, Y.; Maehata, K.

    2009-02-01

    We developed the new liquid-helium-free dilution refrigerator system, in which the Gifford-McMahon (GM) cycle cryocooler and dilution refrigerator (DR) unit are separated. We obtained the base temperature below 50 mK in this DR system. In usual liquid-helium-free DR systems, the DR unit directly couples with GM-cryocooler in the same vacuum chamber. Therefore the mechanical vibration of GM-cryocooler is hardly removed from DR unit. In order to eliminate the vibration problem, the separated vacuum chamber contacting the GM-cryocooler is connected with the DR unit chamber by the flexible hose with length of about 1 meter. Thin flexible tubes used for circulation of the refrigerant gas and radiation shield are installed in the connection hose. The 4He gas, cooled in the GM-cryocooler unit, transfers to the DR unit throw the thin flexible tubes. After cooling the DR unit, the gas returns to GM-cryocooler unit with cooling of the radiation shield. We expect that our separate-type dilution refrigerator becomes a useful piece of apparatus for the low temperature experiments.

  16. Development of GM cryocooler separate type liquid-helium-free {sup 3}He-{sup 4}He dilution refrigerator system

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, Y; Ito, T; Umeno, T; Suzuki, Y; Yoshida, S; Kamioka, Y [Taiyo Nippon Sanso Corporation, 10 Okubo, Tsukuba-shi, 300-2611 (Japan); Maehata, K [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka-shi, 819-0395 (Japan)], E-mail: Yoshihiro.Yamanaka@tn-sanso.co.jp

    2009-02-01

    We developed the new liquid-helium-free dilution refrigerator system, in which the Gifford-McMahon (GM) cycle cryocooler and dilution refrigerator (DR) unit are separated. We obtained the base temperature below 50 mK in this DR system. In usual liquid-helium-free DR systems, the DR unit directly couples with GM-cryocooler in the same vacuum chamber. Therefore the mechanical vibration of GM-cryocooler is hardly removed from DR unit. In order to eliminate the vibration problem, the separated vacuum chamber contacting the GM-cryocooler is connected with the DR unit chamber by the flexible hose with length of about 1 meter. Thin flexible tubes used for circulation of the refrigerant gas and radiation shield are installed in the connection hose. The {sup 4}He gas, cooled in the GM-cryocooler unit, transfers to the DR unit throw the thin flexible tubes. After cooling the DR unit, the gas returns to GM-cryocooler unit with cooling of the radiation shield. We expect that our separate-type dilution refrigerator becomes a useful piece of apparatus for the low temperature experiments.

  17. Development of a 4 K Stirling-Type Pulse Tube Cryocooler for a Mobile Terahertz Detection System

    Science.gov (United States)

    Bradley, P. E.; Gerecht, E.; Radebaugh, R.; Garaway, I.

    2010-04-01

    We discuss in this paper the design and development of a 4 K Stirling-type pulse tube cryocooler for a mobile terahertz detection system. This system integrates new heterodyne detector technology at terahertz frequencies with advancements of Stirling-type pulse tube technology that brings the advent of cooled detector sensitivities in a mobile, compact, and long duration operation system without degradation of sensitivity. To achieve this goal we reduced overall system size, input power, and temperature fluctuations and mechanical vibrations in order to maintain the detector sensitivity. The Stirling-type pulse tube cryocooler developed for this system is a hybrid design employing a He-4 pulse-tube cryocooler operating at 60 Hz and 2.5 MPa average pressure that precools a He-3 pulse tube cryocooler operating at 30 Hz and 1.0 MPa average pressure to achieve 4 K cooling for the terahertz receiver. The He-4 cryocooler employs stainless steel mesh regenerators for the first stage and ErPr spheres for the second stage, while the He-3 cryocooler employs stainless mesh for the first stage and ErPr spheres for the second stage with a layered rare-earth third stage regenerator. Design details and cooler performance goals are discussed.

  18. Performance analysis of a miniature Joule-Thomson cryocooler with and without the distributed J-T effect

    Science.gov (United States)

    Damle, Rashmin; Atrey, Milind

    2015-12-01

    Cryogenic temperatures are obtained with Joule-Thomson (J-T) cryocoolers in an easier way as compared to other cooling techniques. Miniature J-T cryocoolers are often employed for cooling of infrared sensors, cryoprobes, biological samples, etc. A typical miniature J-T cryocooler consists of a storage reservoir/compressor providing the high pressure gas, a finned tube recuperative heat exchanger, an expansion valve/orifice, and the cold end. The recuperative heat exchanger is indispensable for attaining cryogenic temperatures. The geometrical parameters and the operating conditions of the heat exchanger drastically affect the cryocooler performance in terms of cool down time and cooling effect. In the literature, the numerical models for the finned recuperative heat exchanger have neglected the distributed J-T effect. The distributed J-T effect accounts for the changes in enthalpy of the fluid due to changes of pressure in addition to those due to changes of temperature. The objective of this work is to explore the distributed J-T effect and study the performance of a miniature J-T cryocooler with and without the distributed J-T effect. A one dimensional transient model is employed for the numerical analysis of the cryocooler. Cases with different operating conditions are worked out with argon and nitrogen as working fluids.

  19. Computer simulation of molecular sorption in zeolites

    CERN Document Server

    Calmiano, M D

    2001-01-01

    The work presented in this thesis encompasses the computer simulation of molecular sorption. In Chapter 1 we outline the aims and objectives of this work. Chapter 2 follows in which an introduction to sorption in zeolites is presented, with discussion of structure and properties of the main zeolites studied. Chapter 2 concludes with a description of the principles and theories of adsorption. In Chapter 3 we describe the methodology behind the work carried out in this thesis. In Chapter 4 we present our first computational study, that of the sorption of krypton in silicalite. We describe work carried out to investigate low energy sorption sites of krypton in silicalite where we observe krypton to preferentially sorb into straight and sinusoidal channels over channel intersections. We simulate single step type I adsorption isotherms and use molecular dynamics to study the diffusion of krypton and obtain division coefficients and the activation energy. We compare our results to previous experimental and computat...

  20. The effect of TTNT nanotubes on hydrogen sorption using MgH2

    Directory of Open Access Journals (Sweden)

    Mariana Coutinho Brum

    2013-06-01

    Full Text Available Nanotubes are promising materials to be used with magnesium hydride, as catalysts, in order to enhance hydrogen sorption. A study was performed on the hydrogen absorption/desorption properties of MgH2 with the addition of TTNT (TiTanate NanoTubes. The MgH2-TTNT composite was prepared by ball milling and the influence of the TTNT amount (1.0 and 5.0 wt. (% on the hydrogen capacity was evaluated. The milling of pure MgH2 was performed for 24 hours and afterwards the MgH2-TTNT composite was milled for 20 minutes. Transmission Electronic Microscopy (TEM and Scanning Electron Microscopy (SEM were used to evaluate the nanotube synthesis and show the particle morphology of the MgH2-TTNT composite, respectively. The Differential Scanning Calorimetry (DSC examination provided some evidence with the shifting of the peaks obtained when the amount of TTNT is increased. The hydrogen absorption/desorption kinetics tests showed that the TTNT nanotubes can enhance hydrogen sorption effectively and the total hydrogen capacity obtained was 6.5 wt. (%.

  1. The effect of TTNT nanotubes on hydrogen sorption using MgH{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Brum, Mariana Coutinho; Jardim, Paula Mendes; Conceicao, Monique Osorio Talarico da; Santos, Dilson Silva dos, E-mail: monique@metalmat.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (PEMM/COPPEP/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais

    2013-11-01

    Nanotubes are promising materials to be used with magnesium hydride, as catalysts, in order to enhance hydrogen sorption. A study was performed on the hydrogen absorption/desorption properties of MgH{sub 2} with the addition of TTNT (TiTanate nanotubes). The MgH{sub 2} -TTNT composite was prepared by ball milling and the influence of the TTNT amount (1.0 and 5.0 wt. (%)) on the hydrogen capacity was evaluated. The milling of pure MgH{sub 2} was performed for 24 hours and afterwards the MgH{sub 2} -TTNT composite was milled for 20 minutes. Transmission Electronic Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used to evaluate the nanotube synthesis and show the particle morphology of the MgH{sub 2} -TTNT composite, respectively. The Differential Scanning Calorimetry (DSC) examination provided some evidence with the shifting of the peaks obtained when the amount of TTNT is increased. The hydrogen absorption/desorption kinetics tests showed that the TTNT nanotubes can enhance hydrogen sorption effectively and the total hydrogen capacity obtained was 6.5 wt. (%). (author)

  2. Filiform-mode hydride corrosion of uranium surfaces

    Science.gov (United States)

    Hill, M. A.; Schulze, R. K.; Bingert, J. F.; Field, R. D.; McCabe, R. J.; Papin, P. A.

    2013-11-01

    Hydride nucleation and growth has previously been studied in uranium with an air-formed oxide. Preferred directional growth of uranium hydride has not been observed, presumably due to the constraint of the oxide layer and/or the presence of a surface layer distorted by mechanical grinding and polishing. Instead, hydrides typically first form as subsurface blisters that do not exhibit preferred growth directionality. By eliminating the strained surface layer through electropolishing, removing the natural oxide through ion sputtering, avoiding exposure of the uranium to air, and then exposing uranium to high purity hydrogen in an environmental cell, hydride growth patterns emerge that correspond to defect structures within the microstructure. These hydride growth patterns are similar to filiform corrosion, a type of corrosion that frequently forms under thin protective films. This work describes the first reported observation of filiform-like corrosion in uranium. The uranium hydride initiates at defects, but grows into filaments up to 20 μm wide, and tends to form in straight lines, largely propagating along twin boundaries. Propagation is driven by hydrogen reaction at the filament head, promoted by more efficient delivery of reactant. However, this phenomenon does not involve an electrochemical process associated with conventional filiform corrosion and is therefore described as filiform-like. Hydride growth was observed using optical microscopy for a period of nearly three years. Sample characterization included automated electron backscatter diffraction (EBSD) measurements to determine growth directions. Observation of this anomalous hydride growth provides clues as to the mechanisms operating in uranium hydriding for more conventionally prepared sample surfaces.

  3. Development and investigation of novel nanostructures and complex hydrides for hydrogen storage

    Science.gov (United States)

    Niemann, Michael Ulrich

    2009-12-01

    Over the past few years, the need for a clean and renewable fuel has sharply risen. This is due to increasing fossil fuel costs and the desire to limit or eliminate harmful byproducts which are created during the burning of these fuels. Hydrogen is the most abundant element in the universe and can be used in either fuel cells or traditional internal combustion engines to produce energy with no harmful emissions. One of the main obstacles facing the implementation of a hydrogen economy is its storage. Classical methods of storage involve either high and unsafe pressures or liquid storage involving a large amount of energy. Two alternative hydrogen storage methods are investigated---physisorption, which is the weak chemical bonding to a material, as well as chemisorption, which is a strong chemical bond of hydrogen to a host material. Polyaniline, a conducting polymer, is investigated in both its bulk form as well as in nanostructured forms, more precisely nanofibers and nanospheres, to store hydrogen via physisorption. It is found the bulk form of polyaniline can store only approximately 0.5wt.% hydrogen, which is far short of the 6wt.% required for practical applications. Nanofibers and nanospheres, however, have been developed, which can store between 4wt.% and 10wt.% of hydrogen at room temperature with varying kinetics. A new complex metal hydride comprised of LiBH4, LiNH 2 and MgH2 has been developed to store hydrogen via chemisorption. While the parent compounds require high temperatures and suffer of slow kinetics for hydrogen sorption, the work performed as part of this dissertation shows that optimized processing conditions reduce the hydrogen release temperature from 250°C to approximately 150°C, while the addition of nano sized materials has been found to increase the kinetics of hydrogen sorption as well as further decrease the hydrogen release temperature, making this one of the first viable hydrogen storage materials available. This is the first time

  4. Cobalt sorption in silica-pillared clays.

    Science.gov (United States)

    Sampieri, A; Fetter, G; Bosch, P; Bulbulian, S

    2006-01-03

    Silicon pillared samples were prepared following conventional and microwave irradiation methods. The samples were characterized and tested in cobalt sorption. Ethylenediammine was added before cobalt addition to improve the amount of cobalt retained. The amount of cobalt introduced in the original clay in the presence of ethylenediammine was the highest. In calcined pillared clays the cobalt retention with ethylenediammine was lower (ca. 40%). In all cases the presence of ethylenediammine increased twice the amount of cobalt sorption measured for aqueous solutions.

  5. Enhanced fluoride sorption by mechanochemically activated kaolinites.

    Science.gov (United States)

    Meenakshi, S; Sundaram, C Sairam; Sukumar, Rugmini

    2008-05-01

    Kaolinite clay obtained from the mines was processed and studied for its fluoride sorption capacity. The surface area of the clay mineral was increased from 15.11 m(2)/g (raw) to 32.43 m(2)/g (activated) by mechanochemical activation. Batch adsorption studies were conducted to optimize various equilibrating conditions like the effect of contact time, dosage, pH for both raw and micronized kaolinites (RK and MK). The effect of other interfering anions on the defluoridation capacity (DC) of the sorbents was studied. Sorption of fluoride by the sorbents was observed over a wide pH range of 3-11. The studies revealed there is an enhanced fluoride sorption on MK. FTIR and XRD were used for the characterization of the sorbent. The surface morphology of the clay material was observed using SEM. The adsorption of fluoride was studied at three different temperatures, viz., 303, 313 and 323 K. The sorption data obtained at optimized conditions were subjected to Freundlich and Langmuir isotherms. Sorption intensity (1/n) (0.770-0.810) has been evaluated using Freundlich isotherm, whereas the values of sorption capacity Q(0) (0.609, 0.714 and 0.782 mg/g) and binding energy b (0.158, 0.145 and 0.133 L/mg) at three different temperatures have been estimated using Langmuir isotherm. Adsorption process was found to be controlled by both Freundlich and Langmuir isotherms. Thermodynamic studies revealed that the sorption of fluoride on MK is endothermic and a spontaneous process. The kinetic studies indicate that the sorption of fluoride on MK follows pseudo-first-order and intraparticle diffusion models.

  6. Enhanced fluoride sorption by mechanochemically activated kaolinites

    Energy Technology Data Exchange (ETDEWEB)

    Meenakshi, S. [Department of Chemistry, Gandhigram Rural University, Gandhigram 624302, Tamilnadu (India)], E-mail: drs_meena@rediffmail.com; Sundaram, C. Sairam [Department of Science and Humanities, Karaikal Polytechnic College, Karaikal 609609, Puducherry (India); Sukumar, Rugmini [Chemical Sciences and Technologies, Regional Research Laboratory, Trivandrum 695019, Kerala (India)

    2008-05-01

    Kaolinite clay obtained from the mines was processed and studied for its fluoride sorption capacity. The surface area of the clay mineral was increased from 15.11 m{sup 2}/g (raw) to 32.43 m{sup 2}/g (activated) by mechanochemical activation. Batch adsorption studies were conducted to optimize various equilibrating conditions like the effect of contact time, dosage, pH for both raw and micronized kaolinites (RK and MK). The effect of other interfering anions on the defluoridation capacity (DC) of the sorbents was studied. Sorption of fluoride by the sorbents was observed over a wide pH range of 3-11. The studies revealed there is an enhanced fluoride sorption on MK. FTIR and XRD were used for the characterization of the sorbent. The surface morphology of the clay material was observed using SEM. The adsorption of fluoride was studied at three different temperatures, viz., 303, 313 and 323 K. The sorption data obtained at optimized conditions were subjected to Freundlich and Langmuir isotherms. Sorption intensity (1/n) (0.770-0.810) has been evaluated using Freundlich isotherm, whereas the values of sorption capacity Q{sup 0} (0.609, 0.714 and 0.782 mg/g) and binding energy b (0.158, 0.145 and 0.133 L/mg) at three different temperatures have been estimated using Langmuir isotherm. Adsorption process was found to be controlled by both Freundlich and Langmuir isotherms. Thermodynamic studies revealed that the sorption of fluoride on MK is endothermic and a spontaneous process. The kinetic studies indicate that the sorption of fluoride on MK follows pseudo-first-order and intraparticle diffusion models.

  7. Sorption of organophosphate esters by carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Wei; Yan, Li [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Duan, Jinming [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Jing, Chuanyong, E-mail: cyjing@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2014-05-01

    Graphical abstract: The interfacial interactions between the OPE molecules and CNTs. - Highlights: • Oxygen-containing groups on CNTs change the sorption property for OPEs. • Molecular configuration of OPEs has insignificant impact on their sorption. • Hydrophobic, π–π EDA and Brønsted acid–base interaction occurred between the CNTs and OPEs. - Abstract: Insights from the molecular-level mechanism of sorption of organophosphate esters (OPEs) on carbon nanotubes (CNTs) can further our understanding of the fate and transport of OPEs in the environment. The motivation for our study was to explore the sorption process of OPEs on multi-walled CNTs (MWCNTs), single-walled CNTs (SWCNTs) and their oxidized counterparts (O-MWCNTs and O-SWCNTs), and its molecular mechanism over a wide concentration range. The sorption isotherm results revealed that the hydrophobicity of OPEs dominated their affinities on a given CNT and the π–π electron donor–acceptor (EDA) interaction also played an important role in the sorption of aromatic OPEs. This π–π EDA interaction, verified with Raman and FT-IR spectroscopy, could restrict the radial vibration of SWCNTs and affect the deformation vibration γ(CH) bands of OPE molecules. The OPE surface coverage on CNTs, estimated using the nonlinear Dubinin–Ashtakhov model, indicated that the oxygen-containing functional groups on CNTs could interact with water molecules by H-bonding, resulting in a decrease in effective sorption sites. In addition, FTIR analysis also confirmed the occurrence of Brønsted acid–base interactions between OPEs and surface OH groups of SWCNTs. Our results should provide mechanistic insights into the sorption mechanism of OPE contaminants on CNTs.

  8. Peculiarities of sorption isotherm and sorption chemisms of caesium by mixed nickel-potassium ferrocyanide based on hydrated titanium dioxide

    OpenAIRE

    Voronina, A. V.; Semenishchev, V. S.; Nogovitsyna, E. V.; Betenekov, N. D.

    2013-01-01

    Sorption isotherm of caesium from tap water by mixed nickel-potassium ferrocyanide based on hydrated titanium dioxide is obtained for a wide range of concentrations of caesium. It is shown that there are three types of specificity to caesium sorption sites in this sorbent. Sorption chemisms of caesium are studied, factors conditioned high sorption capacity of the sorbent are revealed. It is shown that occupation of sorption sites I and II is well approximated by Langmuir equilibrium and this ...

  9. Self-assembled air-stable magnesium hydride embedded in 3-D activated carbon for reversible hydrogen storage.

    Science.gov (United States)

    Shinde, S S; Kim, Dong-Hyung; Yu, Jin-Young; Lee, Jung-Ho

    2017-06-01

    The rational design of stable, inexpensive catalysts with excellent hydrogen dynamics and sorption characteristics under realistic environments for reversible hydrogen storage remains a great challenge. Here, we present a simple and scalable strategy to fabricate a monodispersed, air-stable, magnesium hydride embedded in three-dimensional activated carbon with periodic synchronization of transition metals (MHCH). The high surface area, homogeneous distribution of MgH2 nanoparticles, excellent thermal stability, high energy density, steric confinement by carbon, and robust architecture of the catalyst resulted in a noticeable enhancement of the hydrogen storage performance. The resulting MHCH-5 exhibited outstanding hydrogen storage performance, better than that of most reported Mg-based hydrides, with a high storage density of 6.63 wt% H2, a rapid kinetics loading in hydrogenation compared to that of commercial MgH2. The origin of the intrinsic hydrogen thermodynamics was elucidated via solid state (1)H NMR. This work presents a readily scaled-up strategy towards the design of realistic catalysts with superior functionality and stability for applications in reversible hydrogen storage, lithium ion batteries, and fuel cells.

  10. In operando visualization of hydride-graphite composites during cyclic hydrogenation by high-resolution neutron imaging

    Science.gov (United States)

    Pohlmann, Carsten; Herbrig, Kai; Gondek, Łukasz; Kardjilov, Nikolay; Hilger, André; Figiel, Henryk; Banhart, John; Kieback, Bernd; Manke, Ingo; Röntzsch, Lars

    2015-03-01

    Hydrogen solid-state storage in metal hydrides has attracted remarkable attention within the past decades due to their high volumetric storage densities at low operating pressures. In particular, recently emerged hydride-graphite composites (HGC) can enable a safe, reliable and very compact hydrogen storage solution for various applications. In this regard, only little is known about the activation behavior of such HGC, their cycle stability and degradation effects. Because of the high sensitivity to hydrogen, neutron imaging offers a distinctive approach to examine in operando reaction fronts, swelling effects and microstructural changes of hydrogen absorbing materials with high spatial and temporal resolution. In this contribution, a comprehensive analysis of various phenomena during activation and cycling of HGC based on a Ti-Mn hydrogen absorbing alloy and expanded natural graphite is reported for the first time. A neutron radiography and tomography set-up with a spatial resolution down to 7 μm was utilized allowing highest detection precision. During initial hydrogenation, regions with enhanced reactivity are observed which contradicts a theoretically expected homogeneous reactivity inside the HGC. These active regions grow with the number of hydrogenation-dehydrogenation cycles until the whole HGC volume uniformly participates in the hydrogen sorption reaction. With regard to long-term hydrogenation-dehydrogenation cycling, inhomogeneous swelling effects were observed from which essential conclusions for technical HGC-based tank systems can be derived.

  11. Technical and economic aspects of hydrogen storage in metal hydrides

    Science.gov (United States)

    Schmitt, R.

    1981-01-01

    The recovery of hydrogen from such metal hydrides as LiH, MgH2, TiH2, CaH2 and FeTiH compounds is studied, with the aim of evaluating the viability of the technique for the storage of hydrogen fuel. The pressure-temperature dependence of the reactions, enthalpies of formation, the kinetics of the hydrogen absorption and desorption, and the mechanical and chemical stability of the metal hydrides are taken into account in the evaluation. Economic aspects are considered. Development of portable metal hydride hydrogen storage reservoirs is also mentioned.

  12. PIE techniques for hydride reorientation test at NDC

    Energy Technology Data Exchange (ETDEWEB)

    Tsuda, Tomohiro; Shinohara, Yasunari; Yamaguchi, Yoichiro [Nuclear Development Corporation, Ibaraki (Japan)

    2008-11-15

    Dry storage of spent fuels in the interim storage facility is being planned in Japan. However, the gradual deterioration of the mechanical property of fuel cladding due to internal pressure and temperature during the storage term is known. Therefore, the integrity of stored fuel rods should be confirmed before the start of dry storage. For the last several years, NDC had a lot of experiences on the hydride reorientation test. The specimen preparation techniques on the hydride reorientation test and the mechanical testing techniques after the hydride reorientation are shown in this paper.

  13. SORPTION PROPERTIES OF PERIODATE OXIDIZED COTTON

    Directory of Open Access Journals (Sweden)

    Tanja Nikolić

    2011-09-01

    Full Text Available The effect of periodate oxidation on the chemical and sorption properties of cotton yarn was investigated by determining aldehyde group content, moisture sorption, water retention and iodine sorption. Oxidation of cotton yarn was performed by varying concentration of sodium periodate solution and reaction time. To measure the aldehyde content present in the oxidized cotton, the aldehyde groups were selectively oxidized to carboxyl groups with sodium chlorite at pH 4-5, at room temperature for 48 h, and carboxyl group content was determined by modified calcium-acetate method. Differences in the sorption properties of untreated and oxidized cotton samples were obtained using conventional methods. The aldehyde groups were introduced into the oxidized cotton up to 99.2 µmol/g. Compared to the untreated fibers, oxidized cotton samples exhibited higher moisture sorption (up to 9% and lower water retention values (up to 19% and iodine sorption values (up to 31%. Based on the obtained results, it can be concluded that the crystalline structure of cellulose is not significantly changed by periodate oxidation, which is of great importance for textile material production.

  14. Hydrogen storage in metal hydrides and complex hydrides; Wasserstoffspeicherung in Metall- und komplexen Hydriden - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bielmann, M.; Zuettel, A.

    2007-07-01

    This final report for the Swiss Federal Office of Energy (SFOE), reports on work done in 2007 at the Swiss Federal Laboratories for Materials Science and Technology EMPA on the storage of hydrogen in metal hydrides and complex hydrides. In particular, the use of tetrahydroborates is noted. The potential of this class of materials is stressed. The structures at room-temperature were examined using neutron and X-ray diffraction methods. Thermodynamic methods helped determine the thermodynamic stability of the materials. Also, a complete energy diagram for the materials was developed. The use of silicon oxide to reduce activation energy and its catalytic effects are discussed. The challenges placed by desorption mechanisms are noted. The authors note that reversibility is basically proven.

  15. Thermodynamics of cationic surfactant sorption onto natural clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, E.J.; Bowman, R.S. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States); Carey, J.W. [Los Alamos National Lab., NM (United States)

    1998-10-15

    Sorption enthalpies of hexadecyltrimethylammonium bromide (HDTMA) as monomers and micelles and tetraethylammonium bromide (TEA) were used with surfactant, counterion, and co-ion sorption isotherms to infer the conformation, sorption mechanism, and relative stability of the sorbed surfactants on natural clinoptilolite. The average value of the sorption enthalpy was {minus}10.38 kJ/mol for monomers, {minus}11.98 kJ/mol for micelles, and +3.03 kJ/mol for TEA. Sorption of monomers produced a lower sorption plateau than equivalent micelle sorption (maxima 145 mmol/kg, 225 mmol/kg). Analysis of the sorption data demonstrated a change in the sorption mechanism at the external cation exchange capacity (ECEC) of clinoptilolite. Sorption data from below and above the ECEC were fit to a simple polynomial model and the Gibbs free energy of sorption ({Delta} G{sub m}{sup 0}) and sorption entropies were calculated. Resultant values of {Delta} G{sub m}{sup 0} were {minus}9.27 and {minus}14.38 kJ/mol for HDTMA monomers and micelles, respectively, for sorption below the ECEC, and {minus}16.11 and {minus}23.10 kJ/mol, respectively, for sorption above the ECEC. The value for TEA was {minus}1.04 kJ/mol, indicating weaker sorption than for HDTMA. Monomer sorption to clinoptilolite exceeded the ECEC, even when the solution concentration was below the critical micelle concentration. Hydrophobic (tail-tail) components of {Delta} G{sub m}{sup 0} were the driving force for sorption of HDTMA, both below and above the ECEC. A significant kinetic effect was observed in the sorption isotherms with a period of rapid sorption followed by slow equilibration requiring 7 days to achieve steady state for HDTMA; TEA equilibration occurred within 24 h.

  16. Thermodynamic design of 10 kW Brayton cryocooler for HTS cable

    Science.gov (United States)

    Chang, Ho-Myung; Park, C. W.; Yang, H. S.; Sohn, Song Ho; Lim, Ji Hyun; Oh, S. R.; Hwang, Si Dole

    2012-06-01

    Thermodynamic design of Brayton cryocooler is presented as part of an ongoing governmental project in Korea, aiming at 1 km HTS power cable in the transmission grid. The refrigeration requirement is 10 kW for continuously sub-cooling liquid nitrogen from 72 K to 65 K. An ideal Brayton cycle for this application is first investigated to examine the fundamental features. Then a practical cycle for a Brayton cryocooler is designed, taking into account the performance of compressor, expander, and heat exchangers. Commercial software (Aspen HYSYS) is used for simulating the refrigeration cycle with real fluid properties of refrigerant. Helium is selected as a refrigerant, as it is superior to neon in thermodynamic efficiency. The operating pressure and flow rate of refrigerant are decided with a constraint to avoid the freezing of liquid nitrogen

  17. Closed cycle cryocooler for low temperature electronics circuits: Cold end test

    Science.gov (United States)

    Pirtle, F. W.

    1983-08-01

    A fabricated MACOR cold end including a metallic coating to prevent helium permeation and a fabricated die post displacer support bearing were combined with a compressor and motor which are standard CTI-CRYOGENICS products. A mechanical test was performed on the test cryocooler to determine that the mechanical test was performed on the test cryocooler to determine that the MACOR displacer was successfully guided by the die post bearing. Thermodynamic tests were conducted to determine the lowest temperature of the 4th (coldest) stage as a function of operating speed, helium charge pressure, 4th stage electrical heat load, and transfer tube diameter. Cooldown and steady state results are reported. Results indicate a low temperature limit of approximately 95K with the current test hardware. Although this represents an improvement from 122K during the program, a resizing will be necessary to reach 10K. The die post displacer support bearing and the MACOR cold finger construction are mechanically satisfactory.

  18. Design of a Cryocooled Sapphire Oscillator for the Cassini Ka-Band Experiment

    Science.gov (United States)

    Dick, G. J.; Wang, R. T.

    1998-04-01

    We present design aspects of a cryogenic sapphire oscillator that is being developed for ultra-high short-term stability and low phase noise in support of the Cassini Ka-band (32-GHz) radio science experiment. With cooling provided by a commercial cryocooler instead of liquid helium, this standard is designed to operate continuously for periods of a year or more. Performance targets are a stability of 3 x 10^(-15) (1 second ≤ τ ≤ 100 seconds) and a phase noise of -73 dBc/Hz at 1 Hz measured at 34 GHz. Test results are reported for several subsystems, including the cryocooler, vibration isolation system, and ruby compensating element.

  19. Testing of a Helium Loop Heat Pipe for Large Area Cryocooling

    Science.gov (United States)

    Ku, Jentung; Robinson, Franklin

    2016-01-01

    Future NASA space telescopes and exploration missions require cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks. One device that can potentially be used to provide closed-loop cryocooling is the cryogenic loop heat pipe (CLHP). A CLHP has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A helium CLHP has been tested extensively in a thermal vacuum chamber using a cryocooler as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components in the 3K temperature range. A copper plate with attached electrical heaters was used to simulate the heat source, and heat was collected by the CLHP evaporator and transferred to the cryocooler for ultimate heat rejection. The helium CLHP thermal performance test included cool-down from the ambient temperature, startup, capillary limit, heat removal capability, rapid power changes, and long duration steady state operation. The helium CLHP demonstrated robust operation under steady state and transient conditions. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully without pre-conditioning by simply applying power to both the capillary pump and the evaporator plate. It could adapt to rapid changes in the heat load, and reach a new steady state very quickly. Heat removal between 10mW and 140mW was demonstrated, yielding a power turn down ratio of 14. When the CLHP capillary limit was exceeded, the loop could resume its normal function by reducing the power to the capillary pump. Steady state operations up to 17 hours at several heat loads were demonstrated. The ability of the helium CLHP to cool large areas was therefore successfully verified.

  20. Hydrodynamic parameters for ErPr cryocooler regenerator fillers under steady and periodic flow conditions

    Science.gov (United States)

    Pathak, M. G.; Patel, V. C.; Ghiaasiaan, S. M.; Mulcahey, T. I.; Helvensteijn, B. P.; Kashani, A.; Feller, J. R.

    2013-12-01

    The regenerator, typically a microporous structure that is subject to periodic flow of a cryogenic fluid, is the most critical component of Pulse Tube or Stirling cryocoolers, which are widely used for high-demand defense and aerospace applications. Despite the critical impact of hydrodynamic irreversibilities in the regenerator on the overall cycle efficiency, the impact of the parameters that influence these losses are poorly understood.

  1. 120 Hz pulse tube cryocooler for fast cooldown to 50 K

    NARCIS (Netherlands)

    Vanapalli, Srinivas; Lewis, Michal; Gan, Zhihua; Radebaugh, Ray

    2007-01-01

    A pulse tube cryocooler operating at 120 Hz with 3.5 MPa average pressure achieved a no-load temperature of about 49.9 K and a cooldown time to 80 K of 5.5 min. The net refrigeration power at 80 K was 3.35 W with an efficiency of 19.7% of Carnot when referred to input pressure-volume (PV or a

  2. Simulation of Thermal Processes in Superconducting Pancake Coils Cooled by GM Cryocooler

    Science.gov (United States)

    Lebioda, M.; Rymaszewski, J.; Korzeniewska, E.

    2014-04-01

    This article presents the thermal model of a small scale superconducting magnetic energy storage system with the closed cycle helium cryocooler. The authors propose the use of contact-cooled coils with maintaining the possibility of the system reconfiguring. The model assumes the use of the second generation superconducting tapes to make the windings in the form of flat discs (pancakes). The paper presents results for a field model of the single pancake coil and the winding system consisting of several coils.

  3. A self-circulation helium liquefaction system with five 4 K G-M cryocoolers

    Science.gov (United States)

    Xu, Dong; Gong, Linghui; Li, Laifeng; Xu, Xiangdong; Xie, Zuqi; Zhao, Hongwei; Guo, Xiaohong

    2011-06-01

    A self-circulation helium liquefaction system (SCHLS) with five 4 K G-M cryocoolers is developed to supply liquid helium (LHe) for SECRAL (a superconducting ECR ion source used in Lanzhou city, China). LHe is vaporized in SECRAL and warmed up to room temperature. SCHLS will re-liquefy the helium gas at a rate of 83.2 L/day under normal atmosphere pressure. With SCHLS, SECRAL system can run online without any interruption of refilling LHe.

  4. A model of a subcritical Joule-Thomson cryocooler with condensation inside the recuperator

    Science.gov (United States)

    Shusser, M.; Ben-Zvi, I.; Maytal, B.-Z.; Grossman, G.

    2009-08-01

    To develop a tool for predicting of heat and mass transfer in Joule-Thomson cryocoolers working at subcritical pressures, we study a counter flow heat exchanger with condensation by employing the integral method. The effects of inlet pressure and working fluid are predicted. We also show that there is an optimal value of the enthalpy difference along the heat exchanger for which its length is minimal.

  5. A model of a subcritical Joule-Thomson cryocooler with condensation inside the recuperator

    Energy Technology Data Exchange (ETDEWEB)

    Shusser, M.; Grossman, G. [Technion, Faculty of Mechanical Engineering, Haifa (Israel); Ben-Zvi, I.; Maytal, B.Z. [Rafael Ltd., Haifa (Israel)

    2009-08-15

    To develop a tool for predicting of heat and mass transfer in Joule-Thomson cryocoolers working at subcritical pressures, we study a counter flow heat exchanger with condensation by employing the integral method. The effects of inlet pressure and working fluid are predicted. We also show that there is an optimal value of the enthalpy difference along the heat exchanger for which its length is minimal. (orig.)

  6. Acute arsenious hydride intoxication. Four cases

    Energy Technology Data Exchange (ETDEWEB)

    Gosselin, B.; Mathieu, D.; Desprez-Nolf, M.; Cosson, A.; Goudemand, J.; Haguenoer, J.M.; Wattel, F.

    1982-02-06

    While engaged in the repair of a zinc furnace, 4 workers were accidentally exposed to arsenious hydride (AsH3) fumes. Acute intravascular haemolysis developed within a few hours. On admission, the patients immediately underwent exsanguino-transfusion; 8.2 to 10.2 l of blood were exchanged through a continuous perfusion pump at the rate of 1 l/hour. Two patients resumed diuresis during transfusion, but the other two required repeated haemodialysis. Between the 10th and 30th days, while renal function was gradually returning to normal, mildly megaloblastic anaemia developed. This was followed during the 3rd month by clinical and electric signs of polyneuritis of the lower and upper limbs, which subsequently regressed. Regular measurements of arsenic levels in the blood and urine were performed between and during exsanguino-transfusion and haemodialysis.

  7. Hydrogen desorption from nanostructured magnesium hydride composites

    Directory of Open Access Journals (Sweden)

    Brdarić Tanja P.

    2007-01-01

    Full Text Available The influence of 3d transition metal addition (Fe, Co and Ni on the desorption properties of magnesium hydride were studied. The ball milling of MgH2-3d metal blends was performed under Ar. Microstructural and morphological characterization were performed by XRD and SEM analysis, while the hydrogen desorption properties were investigated by DSC. The results show a strong correlation between the morphology and thermal stability of the composites. The complex desorption behavior (the existence of more than one desorption peak was correlated with the dispersion of the metal additive particles that appear to play the main role in the desorption. The desorption temperature can be reduced by more than 100 degrees if Fe is added as additive. The activation energy for H2 desorption from the MgH2-Fe composite is 120 kJ/mol, implying that diffusion controls the dehydration process.

  8. Review of magnesium hydride-based materials: development and optimisation

    NARCIS (Netherlands)

    Crivello, J. -C.; Dam, B.; Denys, R. V.; Dornheim, M.; Grant, D. M.; Huot, J.; Jensen, T. R.; de Jongh, P.|info:eu-repo/dai/nl/186125372; Latroche, M.; Milanese, C.; Milcius, D.; Walker, G. S.; Webb, C. J.; Zlotea, C.; Yartys, V. A.

    Magnesium hydride has been studied extensively for applications as a hydrogen storage material owing to the favourable cost and high gravimetric and volumetric hydrogen densities. However, its high enthalpy of decomposition necessitates high working temperatures for hydrogen desorption while the

  9. Direct observation of hydrides formation in cavity-grade niobium

    Directory of Open Access Journals (Sweden)

    F. Barkov

    2012-12-01

    Full Text Available Niobium is an important technological superconductor used to make radio frequency cavities for particle accelerators. Using laser confocal microscopy we have directly investigated hydride precipitates formation in cavity-grade niobium at 77 and 140 K. We have found that large hydrides were usually formed after chemical or mechanical treatments, which are known to lead to a strong degradation of the quality factor known as Q disease. From our experiments we can conclude that hydrides causing Q disease are islands with a characteristic thickness of ≳100  nm and in-plane dimensions 1–10  μm. Our results show that mechanical polishing uploads a lot of hydrogen into bulk niobium while electropolishing leads to a mild contamination. Vacuum treatments at 600–800°C are demonstrated to preclude large hydride formation in line with the absence of Q disease in similarly treated cavities.

  10. Materials science of Mg-Ni-based new hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Orimo, S.; Fujii, H. [Hiroshima Univ. (Japan). Faculty of Integrated Arts and Sciences

    2001-02-01

    One of the advantageous functional properties of Mg alloys (or compounds) is to exhibit the reversible hydriding reaction. In this paper, we present our systematic studies regarding the relationship between nanometer- or atomistic-scale structures and the specific hydriding properties of the Mg-Ni binary system, such as(1) nanostructured (n)-Mg{sub 2}Ni, (2) a mixture of n-Mg{sub 2}Ni and amorphous (a)-MgNi,(3) pure a-MgNi, and(4) n-MgNi{sub 2}. Further studies on(5) an a-MgNi-based system for clarifying the effect of the short-range ordering on the structural and hydriding properties and(6) a MgNi{sub 2}-based system for synthesizing the new Laves phase structure are also presented. The materials science of Mg-Ni-based new hydrides will provide indispensable knowledge for practically developing the Mg alloys as hydrogen-storage materials. (orig.)

  11. Structure and bonding of second-row hydrides

    OpenAIRE

    Blinder, S. M.

    2014-01-01

    The atomic orbitals, hybridization and chemical bonding of the most common hydrides of boron, carbon, nitrogen and oxygen are described. This can be very instructive for beginning students in chemistry and chemical physics.

  12. Artificial exomuscle investigations for applications--metal hydride.

    Science.gov (United States)

    Crevier, Marie-Charlotte; Richard, Martin; Rittenhouse, D Matheson; Roy, Pierre-Olivier; Bédard, Stéphane

    2007-03-01

    In pursuing the development of bionic devices, Victhom identified a need for technologies that could replace current motorized systems and be better integrated into the human body motion. The actuators used to obtain large displacements are noisy, heavy, and do not adequately reproduce human muscle behavior. Subsequently, a project at Victhom was devoted to the development of active materials to obtain an artificial exomuscle actuator. An exhaustive literature review was done at Victhom to identify promising active materials for the development of artificial muscles. According to this review, metal hydrides were identified as a promising technology for artificial muscle development. Victhom's investigations focused on determining metal hydride actuator potential in the context of bionics technology. Based on metal hydride properties and artificial muscle requirements such as force, displacement and rise time, an exomuscle was built. In addition, a finite element model, including heat and mass transfer in the metal hydride, was developed and implemented in FEMLAB software.

  13. DETERMINATION OF METAL HYDRIDE SYSTEMS CHARACTERISTICS WHILE HEATING

    Directory of Open Access Journals (Sweden)

    Yu. Kluchka

    2012-01-01

    Full Text Available Experimental dependence of the pressure of hydrogen in the hydride cartridge when it is heated is obtained. Experimental data prove the theoretical values with an accuracy of ≈ 6%.

  14. Bipolar Nickel-Metal Hydride Battery Being Developed

    Science.gov (United States)

    Manzo, Michelle A.

    1998-01-01

    The NASA Lewis Research Center has contracted with Electro Energy, Inc., to develop a bipolar nickel-metal hydride battery design for energy storage on low-Earth-orbit satellites. The objective of the bipolar nickel-metal hydride battery development program is to approach advanced battery development from a systems level while incorporating technology advances from the lightweight nickel electrode field, hydride development, and design developments from nickel-hydrogen systems. This will result in a low-volume, simplified, less-expensive battery system that is ideal for small spacecraft applications. The goals of the program are to develop a 1-kilowatt, 28-volt (V), bipolar nickel-metal hydride battery with a specific energy of 100 watt-hours per kilogram (W-hr/kg), an energy density of 250 W-hr/liter and a 5-year life in low Earth orbit at 40-percent depth-of-discharge.

  15. High-pressure synthesis of noble metal hydrides.

    Science.gov (United States)

    Donnerer, Christian; Scheler, Thomas; Gregoryanz, Eugene

    2013-04-07

    The formation of hydride phases in the noble metals copper, silver, and gold was investigated by in situ x-ray diffraction at high hydrogen pressures. In the case of copper, a novel hexagonal hydride phase, Cu2H, was synthesised at pressures above 18.6 GPa. This compound exhibits an anti-CdI2-type structure, where hydrogen atoms occupy every second layer of octahedral interstitial sites. In contrast to chemically produced CuH, this phase does not show a change in compressibility compared to pure copper. Furthermore, repeated compression (after decomposition of Cu2H) led to the formation of cubic copper hydride at 12.5 GPa, a phenomenon attributed to an alteration of the microstructure during dehydrogenation. No hydrides of silver (up to 87 GPa) or gold (up to 113 GPa) were found at both room and high temperatures.

  16. Artificial exomuscle investigations for applications-metal hydride

    Energy Technology Data Exchange (ETDEWEB)

    Crevier, Marie-Charlotte; Richard, Martin; Rittenhouse, D Matheson; Roy, Pierre-Olivier; Bedard, Stephane [Victhom Human Bionics Inc., Saint-Augustin-de-Desmaures, QC (Canada)

    2007-03-01

    In pursuing the development of bionic devices, Victhom identified a need for technologies that could replace current motorized systems and be better integrated into the human body motion. The actuators used to obtain large displacements are noisy, heavy, and do not adequately reproduce human muscle behavior. Subsequently, a project at Victhom was devoted to the development of active materials to obtain an artificial exomuscle actuator. An exhaustive literature review was done at Victhom to identify promising active materials for the development of artificial muscles. According to this review, metal hydrides were identified as a promising technology for artificial muscle development. Victhom's investigations focused on determining metal hydride actuator potential in the context of bionics technology. Based on metal hydride properties and artificial muscle requirements such as force, displacement and rise time, an exomuscle was built. In addition, a finite element model, including heat and mass transfer in the metal hydride, was developed and implemented in FEMLAB software. (review article)

  17. Out-of-pile accelerated hydriding of Zircaloy fasteners

    Energy Technology Data Exchange (ETDEWEB)

    Clayton, J.C.

    1979-10-01

    Mechanical joints between Zircaloy and nickel-bearing alloys, mainly the Zircaloy-4/Inconel-600 combination, were exposed to water at 450/sup 0/F and 520/sup 0/F to study hydriding of Zircaloy in contact with a dissimilar metal. Accelerated hydriding of the Zircaloy occurred at both temperatures. At 450/sup 0/F the dissolved hydrogen level of the water was over ten times that at 520/sup 0/F. At 520/sup 0/F the initially high hydrogen ingress rate decreased rapidly as exposure time increased and was effectively shut off in about 25 days. Severely hydrided Zircaloy components successfully withstood thermal cycling and mechanical testing. Chromium plating of the nickel-bearing parts was found to be an effective and practical barrier in preventing nickel-alloy smearing and accelerated hydriding of Zircaloy.

  18. A vibration free closed-cycle 1 K cryostat with a 4 K pulse tube cryocooler

    Science.gov (United States)

    Wang, Chao; Lichtenwalter, Ben

    2014-01-01

    A 1 K closed-cycle cryostat, pre-cooled by a 4 K pulse tube cryocooler, has been developed. The Cryomech PT410 pulse tube cryocooler liquefies helium in a vacuum insulated sleeve at a pressure of ˜1 atm. Liquid helium flows through a JT valve and into a 1 K pot that is evacuated by a vacuum pump. The discharged gas from the vacuum is routed to the top of the sleeve to be liquefied. This design accomplishes closed-cycle 1 K refrigeration and provides continuous cooling below 2 K. Using two XDS10 vacuum pumps and with the JT valve optimized for maximum cooling capacity, the 1 K cooling station can reach a no-load temperature of 1.51 K and provide a capacity of 225 mW at 1.76 K. The temperature oscillations on the 4 K and 1 K cooling stations are ± 3 mK. The cryostat is designed so that there is no direct mechanical contact between the pulse tube cryocooler heat exchangers and the 1 K cooling station. This design feature enables exceptionally low vibration operation at the 1 K cooling station.

  19. Operation of A Sunpower M87 Cryocooler In A Magnetic Field

    Science.gov (United States)

    Breon, S. R.; Shirey, K. A.; Banks, I. S.; Warner, B. A.; Boyle, R. F.; Mustafi, S.; Krebs,Carolyn A. (Technical Monitor)

    2002-01-01

    The Alpha Magnetic Spectrometer-02 (AMS-02) is an experiment that will be flown as an attached payload on the International Space Station to detect dark matter and antimatter. It uses large superconducting magnets cooled with superfluid helium to bend the path of cosmic particles through a series of detectors, which then measure the mass, speed, charge, and direction of the particles. Four Sunpower M87N Stirling-cycle cryocoolers are used to extend the mission life by cooling the outer vapor-cooled shield of the dewar. The main magnet coils are separated by a distance of approximately 1 m and the coolers are located approximately 1.5 m from the center line of the magnet, where the field is as high as 925 gauss perpendicular to the cryocooler axis and 400 gauss along the cryocooler axis. Interactions between the applied magnetic field and the linear motor may result in additional forces and torques on the compressor piston. Motion of the compressor arid displacer pistons through the magnetic field spatial gradients will generate eddy currents. Additional eddy currents are created during magnet charge, discharge, and quench by the time-varying magnetic field. The results of tests to determine the magnitude of the forces, torques, and heating effects, as well as the need for additional magnetic shielding, are presented.

  20. Cool-down acceleration of G-M cryocoolers with thermal oscillations passively damped by helium

    Science.gov (United States)

    Webber, R. J.; Delmas, J.

    2015-12-01

    4 K Gifford-McMahon cryocoolers suffer from inherent temperature oscillations which can be a problem for certain attached electronic instrumentation. Sumitomo Heavy Industries has exploited the high volumetric specific heat of super-critical He to quell these oscillations (approx. 10 dB) by strongly thermally linking a separate vessel of He to the second stage; no significant thermal resistance is added between the payload and the working gas of the cryocooler. A noticeable effect of the helium damper is to increase the cool-down time of the second stage below 10 K. For the operation of niobium-based superconducting electronics (NbSCE), a common practice is to warm the circuits above the critical temperature (∼9 K) and then cool to the operating point in order to redistribute trapped magnetic fluxons, so for NbSCE users, the time to cool from 10 K is important. The gas in the helium damper is shared between a room-temperature buffer tank and the 2nd stage vessel, which are connected by a capillary tube. We show that the total cool-down time below 10 K can be substantially reduced by introducing a combination of thermal linkages between the cryocooler and the capillary tube and in-line relief valves, which control the He mass distribution between the warm canister and cold vessel. The time to reach operating temperature from the superconducting transition has been reduced to <25% of the time needed without these low-cost modifications.

  1. A novel coupled VM-PT cryocooler operating at liquid helium temperature

    Science.gov (United States)

    Pan, Changzhao; Zhang, Tong; Zhou, Yuan; Wang, Junjie

    2016-07-01

    This paper presents experimental results on a novel two-stage gas-coupled VM-PT cryocooler, which is a one-stage VM cooler coupled a pulse tube cooler. In order to reach temperatures below the critical point of helium-4, a one-stage coaxial pulse tube cryocooler was gas-coupled on the cold end of the former VM cryocooler. The low temperature inertance tube and room temperature gas reservoir were used as phase shifters. The influence of room temperature double-inlet was first investigated, and the results showed that it added excessive heat loss. Then the inertance tube, regenerator and the length of the pulse tube were researched experimentally. Especially, the DC flow, whose function is similar to the double-orifice, was experimentally studied, and shown to contribute about 0.2 K for the no-load temperature. The minimum no-load temperature of 4.4 K was obtained with a pressure ratio near 1.5, working frequency of 2.2 Hz, and average pressure of 1.73 MPa.

  2. Reduction of temperature fluctuation within low temperature region using a cryocooler.

    Science.gov (United States)

    Nakamura, Daiki; Hasegawa, Yasuhiro; Murata, Masayuki; Yamamoto, Hiroya; Tsunemi, Fumiaki; Komine, Takashi

    2011-04-01

    Modeling and experiments are performed to decrease temperature fluctuation generated by the periodic motion of the displacer in a Gifford-McMahon (GM) type cryocooler within the low-temperature region. The one-dimensional heat equation allows us to show that thermal diffusivity is an essential factor to achieve much smaller temperature fluctuation, and fiber-reinforced plastic (FRP) with low thermal diffusivity makes it possible to reduce the temperature fluctuation dramatically. Based on the model, experiments are performed to vary the thickness of two FRP dampers, on the cryohead of the cryocooler and on the sample stage. As a result, the FRP dampers enable us to achieve the temperature fluctuations of only 0.7 mK, corresponding to a standard deviation of 0.25 mK, when the sample stage is maintained at 4.2000 K, even if a GM cryocooler is utilized for cooling the temperature, which introduces an initial temperature fluctuation of 282 mK at the cryohead.

  3. Experimental investigation and optimization of small-scale helium liquefaction with multi-cryocoolers

    Science.gov (United States)

    Xu, Dong; Gong, Linghui; Li, Laifeng; Xu, Xiangdong; Liu, Huiming; Huang, Rongjin

    2015-07-01

    Small-scale helium liquefiers using regenerative cryocoolers with cooling power up to 1.5 W at 4.2 K could be used to re-liquefy evaporated helium gas of small- and medium-sized cryogenic devices such as MEG and PPMS. A serial-parallel-path helium liquefier with a liquefaction rate of 83 Litres per day (L/d) using five 4 K G-M cryocoolers is developed, and has been applied to the Wuhan National High Magnetic Field Center (WHMFC) in China. Different from parallel-path helium liquefier, the helium gas is effectively, stepwise precooled by heat exchangers on multi-cold flanges, and thus the additional purifier and precooling coil heat exchangers on the thinner part of the cold head cylinder containing the 2nd stage displacer could be removed to simplify the construction. Through theoretical calculation and conclusive analysis, an optimum configuration is proposed and makes a reference to the design of serial-parallel-path helium liquefier with multi-cryocoolers.

  4. Compact high-efficiency linear cryocooler in single-piston moving magnet design for HOT detectors

    Science.gov (United States)

    Rühlich, I.; Mai, M.; Rosenhagen, C.; Withopf, A.; Zehner, S.

    2012-06-01

    State of the art Mid Wave IR-technology has the potential to rise the FPA temperature from 77K to 130-150K (High Operation Temperature, HOT). Using a HOT FPA will significantly lower SWaP and keep those parameters finally dominated by the employed cryocooler. Therefore, compact high performance cryocoolers are mandatory. AIM has developed the SX040 cooler, optimized for FPA temperatures of about 95K (presented at SPIE 2010). The SX040 cooler incorporates a high efficient dual piston driving mechanism resulting in a very compact compressor of less than 100mm length. Higher compactness - especially shorter compressors - can be achieved by change from dual to single piston design. The new SX030 compressor has such a single piston Moving Magnet driving mechanism resulting in a compressor length of about 60mm. Common for SX040 and SX030 family is a Moving Magnet driving mechanism with coils placed outside the helium vessel. In combination with high performance plastics for the piston surfaces this design enables lifetimes in excess of 20,000h MTTF. Because of the higher FPA temperature and a higher operating frequency also a new displacer needs to be developed. Based on the existing 1/4" coldfinger interface AIM developed a new displacer optimized for an FPA temperature of 140K and above. This paper gives an overview on the development of this new compact single piston cryocooler. Technical details and performance data will be shown.

  5. Joule-Thomson cryocooler with neon and nitrogen mixture using commercial air-conditioning compressors

    Science.gov (United States)

    Lee, Jisung; Oh, Haejin; Baek, Seungwhan; Lee, Cheonkyu; Jeong, Sangkwon

    2014-01-01

    A 2-stage mixed refrigerant (MR) Joule-Thomson (JT) cryocooler was designed for cooling high temperature superconducting cable below 70 K. The low temperature cycle was to operate with neon-nitrogen mixture, and the required compression ratio was approximately 24 when the suction pressure was 100 kPa. The high compression ratio of 24, the low pressure of 100 kPa at compressor suction, and the working fluid with high heat of compression were challenging issues to existing typical compression systems. We developed an innovative compression system with commercial oil-lubricated air-conditioning compressors. They were 2-stage rotary compressors originally designed for R410Aand connected in series. The compressors were modified to accommodate effective intercooling at every stage to alleviate compressor overheating problem. Additionally, fine-grade three-stage oil filters, an adsorber, and driers were installed at the discharge line to avoid a potential clogging problem from oil mist and moisture at low temperature sections. The present compression system was specifically demonstrated with a neon-nitrogen MR JT cryocooler. The operating pressure ratio was able to meet the designed specifications, and the recorded no-load mini mum temperature was 63.5 K . Commercial air-conditioning compressors were successfully applied to the high-c ompression ratio MR JT cryocooler with adequate modification using off-the-shelf components.

  6. Linear Resonance Compressor for Stirling-Type Cryocoolers Activated by Piezoelectric Stack-Type Elements

    Science.gov (United States)

    Sobol, S.; Grossman, G.

    2015-12-01

    A novel type of a PZT- based compressor operating at mechanical resonance, suitable for pneumatically-driven Stirling-type cryocoolers was developed theoretically and built practically during this research. A resonance operation at relatively low frequency was achieved by incorporating the piezo ceramics into the moving part, and by reducing the effective piezo stiffness using hydraulic amplification. The detailed concept, analytical model and the test results of the preliminary prototype were reported earlier and presented at ICC17 [2]. A fine agreement between the simulations and experiments spurred development of the current actual compressor designed to drive a miniature Pulse Tube cryocooler, particularly our MTSa model, which operates at 103 Hz and requires an average PV power of 11 W, filling pressure of 40 Bar and a pressure ratio of 1.3. The paper concentrates on design aspects and optimization of the governing parameters. The small stroke to diameter ratio (about 1:10) allows for the use of a composite diaphragm instead of a clearance-seal piston. The motivation is to create an adequate separation between the working fluid and the buffer gas of the compressor, thus preventing possible contamination in the cryocooler. Providing efficiency and power density similar to those of conventional linear compressors, the piezo compressor may serve as a good alternative for cryogenic applications requiring extreme reliability and absence of magnetic field interference.

  7. Linear-drive cryocoolers for the Department of Defense standard advanced dewar assembly (SADA)

    Science.gov (United States)

    Tate, Garin S.

    2005-05-01

    The Standard Advanced Dewar Assembly (SADA) is the critical module in the Department of Defense (DoD) standardization of scanning second-generation thermal imaging systems. The DoD has established a family of SADAs to fulfill a range of performance requirements for various platforms. The SADA consists of the Infrared Focal Plane Array (IRFPA), Dewar, Command & Control Electronics (C&CE), and the cryogenic cooler, and is used in platforms such as the Apache helicopter, the M1A2 Abrams main battle tank, the M2 Bradley Infantry Fighting Vehicle, and the Javelin Command Launch Unit (CLU). In support of the family of SADAs, the DoD defined a complementary family of tactical linear drive cryocoolers. The Stirling cycle linear drive cryocoolers are utilized to cool the Infrared Focal Plane Arrays (IRFPAs) in the SADAs. These coolers are required to have low input power, a quick cool-down time, low vibration output, low audible noise, and a higher reliability than currently fielded rotary coolers. These coolers must also operate in a military environment with its inherent high vibration level and temperature extremes. This paper will (1) outline the characteristics of each cryocooler, (2) present the status and results of qualification tests, (3) present the status of production efforts, and (4) present the status of efforts to increase linear drive cooler reliability.

  8. Performance of the helium dewar and cryocoolers of ASTRO-H SXS

    Science.gov (United States)

    Fujimoto, Ryuichi; Takei, Yoh; Mitsuda, Kazuhisa; Yamasaki, Noriko Y.; Tsujimoto, Masahiro; Koyama, Shu; Ishikawa, Kumi; Sugita, Hiroyuki; Sato, Yoichi; Shinozaki, Keisuke; Okamoto, Atsushi; Kitamoto, Shunji; Hoshino, Akio; Sato, Kosuke; Ezoe, Yuichiro; Ishisaki, Yoshitaka; Yamada, Shinya; Seta, Hiromi; Ohashi, Takaya; Tamagawa, Toru; Noda, Hirofumi; Sawada, Makoto; Tashiro, Makoto; Yatsu, Yoichi; Mitsuishi, Ikuyuki; Kanao, Kenichi; Yoshida, Seiji; Miyaoka, Mikio; Tsunematsu, Shoji; Otsuka, Kiyomi; Narasaki, Katsuhiro; DiPirro, Michael J.; Shirron, Peter J.; Sneiderman, Gary A.; Kilbourne, Caroline A.; Porter, F. Scott; Chiao, Meng P.; Eckart, Megan E.; Kelley, Richard L.

    2016-07-01

    The Soft X-ray Spectrometer (SXS) is a cryogenic high-resolution X-ray spectrometer onboard the ASTRO-H satellite, that achieves energy resolution better than 7 eV at 6 keV, by operating the detector array at 50 mK using an adiabatic demagnetization refrigerator. The cooling chain from room temperature to the ADR heat sink is composed of 2-stage Stirling cryocoolers, a 4He Joule-Thomson cryocooler, and super uid liquid He, and is installed in a dewar. It is designed to achieve a helium lifetime of more than 3 years with a minimum of 30 liters. The satellite was launched on 2016 February 17, and the SXS worked perfectly in orbit, until March 26 when the satellite lost its function. It was demonstrated that the heat load on the He tank was about 0.7 mW, which would have satisfied the lifetime requirement. This paper describes the design, results of ground performance tests, prelaunch operations, and initial operation and performance in orbit of the flight dewar and cryocoolers.

  9. Electronic structure of ternary hydrides based on light elements

    Energy Technology Data Exchange (ETDEWEB)

    Orgaz, E. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico)]. E-mail: orgaz@eros.pquim.unam.mx; Membrillo, A. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico); Castaneda, R. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico); Aburto, A. [Departamento de Fisica, Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico)

    2005-12-08

    Ternary hydrides based on light elements are interesting owing to the high available energy density. In this work we focused into the electronic structure of a series of known systems having the general formula AMH{sub 4}(A=Li,Na,M=B,Al). We computed the energy bands and the total and partial density of states using the linear-augmented plane waves method. In this report, we discuss the chemical bonding in this series of complex hydrides.

  10. Ab-Initio Study of the Group 2 Hydride Anions

    Science.gov (United States)

    Harris, Joe P.; Wright, Timothy G.; Manship, Daniel R.

    2013-06-01

    The beryllium hydride (BeH)- dimer has recently been shown to be surprisingly strongly bound, with an electronic structure which is highly dependent on internuclear separation. At the equilibrium distance, the negative charge is to be found on the beryllium atom, despite the higher electronegativity of the hydrogen. The current study expands this investigation to the other Group 2 hydrides, and attempts to explain these effects. M. Verdicchio, G. L. Bendazzoli, S. Evangelisti, T. Leininger J. Phys. Chem. A, 117, 192, (2013)

  11. Suppression of the critical temperature in binary vanadium hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, M.D., E-mail: michael.dolan@csiro.au [CSIRO Energy Technology, 1 Technology Court, Pullenvale, QLD 4069 (Australia); McLennan, K.G. [CSIRO Energy Technology, 1 Technology Court, Pullenvale, QLD 4069 (Australia); Chandra, D. [Department of Chemical and Materials Engineering, University of Nevada, Reno, Reno, NV 89557 (United States); Kochanek, M.A. [CSIRO Energy Technology, 1 Technology Court, Pullenvale, QLD 4069 (Australia); Song, G. [CSIRO Process Science and Engineering, Gate 4, Normanby Rd, Clayton, VIC 3168 (Australia)

    2014-02-15

    Highlights: • Addition of 10 mol% Cr to V increases the β-hydride T{sub C} to >200 °C. • Addition of 10 mol% Ni to V increases the β-hydride T{sub C} to >400 °C. • Addition of 10 mol% Al to V decreases the β-hydride T{sub C} to <30 °C. • V{sub 90}Al{sub 10} membrane can be cycled to <30 °C under H{sub 2} without β-hydride formation. -- Abstract: The tendency of vanadium-based alloy membranes to embrittle is the biggest commercialisation barrier for this hydrogen separation technology. Excessive hydrogen absorption and the α → β hydride transition both contribute to brittle failure of these membranes. Alloying is known to reduce absorption, but the influence of alloying on hydride phase formation under conditions relevant to membrane operation has not been studied in great detail previously. Here, the effect of Cr, Ni, and Al alloying additions on V–H phase equilibrium has been studied using hydrogen absorption measurements and in situ X-ray diffraction studies. The addition of 10 mol% Ni increases the critical temperature for α + β hydride formation to greater than 400 °C, compared to 170 °C for V. Cr also increases the critical temperature, to between 200 and 300 °C. The addition of 10 mol% Al, however, suppresses the critical temperature to less than 30 °C, thereby enabling this material to be cycled thermally and hydrostatically while precluding formation of the β-hydride phase. This is despite Al also decreasing hydrogen absorption. The implication of this finding is that one of the mechanisms of brittle failure in vanadium-based hydrogen-selective membranes has been eliminated, thereby increasing the robustness of this material relative to V.

  12. Method of selective reduction of polyhalosilanes with alkyltin hydrides

    Science.gov (United States)

    Sharp, Kenneth G.; D'Errico, John J.

    1989-01-01

    The invention relates to the selective and stepwise reduction of polyhalosilanes by reacting at room temperature or below with alkyltin hydrides without the use of free radical intermediates. Alkyltin hydrides selectively and stepwise reduce the Si--Br, Si--Cl, or Si--I bonds while leaving intact any Si--F bonds. When two or more different halogens are present on the polyhalosilane, the halogen with the highest atomic weight is preferentially reduced.

  13. Method of selective reduction of halodisilanes with alkyltin hydrides

    Science.gov (United States)

    D'Errico, John J.; Sharp, Kenneth G.

    1989-01-01

    The invention relates to the selective and sequential reduction of halodisilanes by reacting these compounds at room temperature or below with trialkyltin hydrides or dialkyltin dihydrides without the use of free radical intermediates. The alkyltin hydrides selectively and sequentially reduce the Si-Cl, Si-Br or Si-I bonds while leaving intact the Si-Si and Si-F bonds present.

  14. Electronic structure and optical properties of lightweight metal hydrides

    NARCIS (Netherlands)

    Setten, van M.J.; Popa, V.A.; Wijs, de G.A.; Brocks, G.

    2007-01-01

    We study the dielectric functions of the series of simple hydrides LiH, NaH, MgH2, and AlH3, and of the complex hydrides Li3AlH6, Na3AlH6, LiAlH4, NaAlH4, and Mg(AlH4)2, using first-principles density-functional theory and GW calculations. All compounds are large gap insulators with GW single-partic

  15. Experimental study of a mixed refrigerant Joule-Thomson cryocooler using a commercial air-conditioning scroll compressor

    Science.gov (United States)

    Lee, Jisung; Lee, Kyungsoo; Jeong, Sangkwon

    2013-05-01

    Mixed refrigerant Joule-Thomson (MR J-T) cryocoolers have been used to create cryogenic temperatures and are simple, efficient, cheap, and durable. However, compressors for MR J-T cryocoolers still require optimization. As the MR J-T cryocooler uses a commercial scroll compressor developed for air-conditioning systems, compressor overheating due to the use of less optimized refrigerants may not be negligible, and could cause compressor malfunction due to burn-out of scroll tip seals. Therefore, in the present study, the authors propose procedures to optimize compressor operation to avoid the overheating issue when the MR J-T cryocooler is used with a commercial oil lubricated scroll compressor, and the present experimental results obtained for a MR J-T cryocooler. A single stage 1.49 kW (2 HP) scroll compressor designed for R22 utilizing a mixture of nitrogen and hydrocarbons was used in the present study. As was expected, compressor overheating and irreversible high temperatures at a compressor discharge port were found at the beginning of compressor operation, which is critical, and hence, the authors used a water injection cooling system for the compressor to alleviate temperature overshooting. In addition, a portion of refrigerant in the high-pressure stream was by-passed into the compressor suction port. This allowed an adequate compression ratio, prevented excessive temperature increases at the compressor discharge, and eventually enabled the MR J-T cryocooler to operate stably at 121 K. The study shows that commercial oil lubricated scroll compressors can be used for MR J-T cryocooling systems if care is exercised to avoid compressor overheating.

  16. Sorption of Organic Compounds in Soil Organic Matter

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Soil organic matter (SOM)is the predominant component for sorption of hydrophobic organic compouds in soil and sorption by SOM ultimately affects chemical fate and availability in soil ,and the degree of remedia tion success of contaminated soils. This paper summarizes the latest development on sorption of organic com pounds in soil (natural) organic matter, addresses four sorption mechanisms: surface adsorption, solid - phase partitioning,dual-mode sorption,and fixed-pore sorption model ,and presents future research directions as well.

  17. Optimization of Hydride Rim Formation in Unirradiated Zr 4 Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Shimskey, Rick W.; Hanson, Brady D.; MacFarlan, Paul J.

    2013-09-30

    The purpose of this work is to build on the results reported in the M2 milestone M2FT 13PN0805051, document number FCRD-USED-2013-000151 (Hanson, 2013). In that work, it was demonstrated that unirradiated samples of zircaloy-4 cladding could be pre-hydrided at temperatures below 400°C in pure hydrogen gas and that the growth of hydrides on the surface could be controlled by changing the surface condition of the samples and form a desired hydride rim on the outside diameter of the cladding. The work performed at Pacific Northwest National Laboratory since the issuing of the M2 milestone has focused its efforts to optimize the formation of a hydride rim on available zircaloy-4 cladding samples by controlling temperature variation and gas flow control during pre-hydriding treatments. Surface conditioning of the outside surface was also examined as a variable. The results of test indicate that much of the variability in the hydride thickness is due to temperature variation occurring in the furnaces as well as how hydrogen gas flows across the sample surface. Efforts to examine other alloys, gas concentrations, and different surface conditioning plan to be pursed in the next FY as more cladding samples become available

  18. Mechanochemical synthesis of nanostructured chemical hydrides in hydrogen alloying mills

    Energy Technology Data Exchange (ETDEWEB)

    Wronski, Z. [CANMET' s Materials Technology Laboratory, Natural Resources Canada, Ottawa (Canada) and Department of Mechanical Engineering, University of Waterloo, Waterloo, Ont., Canada N2L 3G1 (Canada)]. E-mail: zwronski@nrcan.gc.ca; Varin, R.A. [Department of Mechanical Engineering, University of Waterloo, Waterloo, Ont., Canada N2L 3G1 (Canada); Chiu, C. [Department of Mechanical Engineering, University of Waterloo, Waterloo, Ont., Canada N2L 3G1 (Canada); Czujko, T. [Department of Mechanical Engineering, University of Waterloo, Waterloo, Ont., Canada N2L 3G1 (Canada); Calka, A. [Department of Materials Science and Engineering, University of Wollongong, NSW 2518 (Australia)

    2007-05-31

    Mechanical alloying of magnesium metal powders with hydrogen in specialized hydrogen ball mills can be used as a direct route for mechanochemical synthesis of emerging chemical hydrides and hydride mixtures for advanced solid-state hydrogen storage. In the 2Mg-Fe system, we have successfully synthesized the ternary complex hydride Mg{sub 2}FeH{sub 6} in a mixture with nanometric Fe particles. The mixture of complex magnesium-iron hydride and nano-iron released 3-4 wt.%H{sub 2} in a thermally programmed desorption experiment at the range 285-295 {sup o}C. Milling of the Mg-2Al powder mixture revealed a strong competition between formation of the Al(Mg) solid solution and the {beta}-MgH{sub 2} hydride. The former decomposes upon longer milling as the Mg atoms react with hydrogen to form the hydride phase, and drive the Al out of the solid solution. The mixture of magnesium dihydride and nano-aluminum released 2.1 wt.%H{sub 2} in the temperature range 329-340 {sup o}C in the differential scanning calorimetry experiment. The formation of MgH{sub 2} was suppressed in the Mg-B system; instead, a hydrogenated amorphous phase (Mg,B)H {sub x}, was formed in a mixture with nanometric MgB{sub 2}. Annealing of the hydrogen-stabilized amorphous mixture produced crystalline MgB{sub 2}.

  19. Metal Hydrides for High-Temperature Power Generation

    Directory of Open Access Journals (Sweden)

    Ewa C. E. Rönnebro

    2015-08-01

    Full Text Available Metal hydrides can be utilized for hydrogen storage and for thermal energy storage (TES applications. By using TES with solar technologies, heat can be stored from sun energy to be used later, which enables continuous power generation. We are developing a TES technology based on a dual-bed metal hydride system, which has a high-temperature (HT metal hydride operating reversibly at 600–800 °C to generate heat, as well as a low-temperature (LT hydride near room temperature that is used for hydrogen storage during sun hours until there is the need to produce electricity, such as during night time, a cloudy day or during peak hours. We proceeded from selecting a high-energy density HT-hydride based on performance characterization on gram-sized samples scaled up to kilogram quantities with retained performance. COMSOL Multiphysics was used to make performance predictions for cylindrical hydride beds with varying diameters and thermal conductivities. Based on experimental and modeling results, a ~200-kWh/m3 bench-scale prototype was designed and fabricated, and we demonstrated the ability to meet or exceed all performance targets.

  20. Novel fuel cell stack with coupled metal hydride containers

    Science.gov (United States)

    Liu, Zhixiang; Li, Yan; Bu, Qingyuan; Guzy, Christopher J.; Li, Qi; Chen, Weirong; Wang, Cheng

    2016-10-01

    Air-cooled, self-humidifying hydrogen fuel cells are often used for backup and portable power sources, with a metal hydride used as the hydrogen storage material. To provide a stable hydrogen flow to the fuel cell stack, heat must be provided to the metal hydride. Conventionally, the heat released from the exothermic reaction of hydrogen and oxygen in the fuel cell stack to the exhaust air is used to heat a separate metal hydride container. In this case, the heat is only partially used instead of being more closely coupled because of the heat transfer resistances in the system. To achieve better heat integration, a novel scheme is proposed whereby hydrogen storage and single fuel cells are more closely coupled. Based on this idea, metal hydride containers in the form of cooling plates were assembled between each pair of cells in the stack so that the heat could be directly transferred to a metal hydride container of much larger surface-to-volume ratio than conventional separate containers. A heat coupled fuel cell portable power source with 10 cells and 11 metal hydride containers was constructed and the experimental results show that this scheme is beneficial for the heat management of fuel cell stack.

  1. The use of metal hydrides in fuel cell applications

    Directory of Open Access Journals (Sweden)

    Mykhaylo V. Lototskyy

    2017-02-01

    Full Text Available This paper reviews state-of-the-art developments in hydrogen energy systems which integrate fuel cells with metal hydride-based hydrogen storage. The 187 reference papers included in this review provide an overview of all major publications in the field, as well as recent work by several of the authors of the review. The review contains four parts. The first part gives an overview of the existing types of fuel cells and outlines the potential of using metal hydride stores as a source of hydrogen fuel. The second part of the review considers the suitability and optimisation of different metal hydrides based on their energy efficient thermal integration with fuel cells. The performances of metal hydrides are considered from the viewpoint of the reversible heat driven interaction of the metal hydrides with gaseous H2. Efficiencies of hydrogen and heat exchange in hydrogen stores to control H2 charge/discharge flow rates are the focus of the third section of the review and are considered together with metal hydride – fuel cell system integration issues and the corresponding engineering solutions. Finally, the last section of the review describes specific hydrogen-fuelled systems presented in the available reference data.

  2. Metal hydrides based high energy density thermal battery

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Zhigang Zak, E-mail: zak.fang@utah.edu [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Zhou, Chengshang; Fan, Peng [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Udell, Kent S. [Department of Metallurgical Engineering, The University of Utah, 50 S. Central Campus Dr., Room 2110, Salt Lake City, UT 84112-0114 (United States); Bowman, Robert C. [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Vajo, John J.; Purewal, Justin J. [HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265 (United States); Kekelia, Bidzina [Department of Metallurgical Engineering, The University of Utah, 50 S. Central Campus Dr., Room 2110, Salt Lake City, UT 84112-0114 (United States)

    2015-10-05

    Highlights: • The principle of the thermal battery using advanced metal hydrides was demonstrated. • The thermal battery used MgH{sub 2} and TiMnV as a working pair. • High energy density can be achieved by the use of MgH{sub 2} to store thermal energy. - Abstract: A concept of thermal battery based on advanced metal hydrides was studied for heating and cooling of cabins in electric vehicles. The system utilized a pair of thermodynamically matched metal hydrides as energy storage media. The pair of hydrides that was identified and developed was: (1) catalyzed MgH{sub 2} as the high temperature hydride material, due to its high energy density and enhanced kinetics; and (2) TiV{sub 0.62}Mn{sub 1.5} alloy as the matching low temperature hydride. Further, a proof-of-concept prototype was built and tested, demonstrating the potential of the system as HVAC for transportation vehicles.

  3. Metallographic and fractographic observations of hydrides during delayed hydride cracking in Zr-2.5% Nb alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jovanovic, M.T.; Eadie, R.L. [Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Chemical and Materials Engineering; Shek, G.K.; Seahra, H. [Ontario Hydro Technologies, Toronto, Ontario (Canada)

    1998-01-01

    Potential drop measurements, optical microscopy, and scanning electron microscopy were performed to study the mechanism of delayed hydride cracking (DHC), the relation of the fracture to the hydride morphology, and the fractography of the DHC mechanism. The material used in this study was taken from modified extrusions of the material used to manufacture Zr-2.5% Nb pressure tubes. The material was electrolytically hydrided to approximately 60 {micro}g/g before testing. Cracking tests were carried out at 250 C with an applied K{sub 1} of 12 MPa {radical}m. The number of potential jumps was strongly correlated to the number of striations on the fracture surface. The results indicate that the DHC process occurs in these samples in an intermittent fashion. Brittle fracture is the operating fracture mechanism for the hydrides that cover most of the fracture surface, but there are some regions of ductile fracture both within the fracture and at the striations.

  4. Trialkylborane-Assisted CO(2) Reduction by Late Transition Metal Hydrides.

    Science.gov (United States)

    Miller, Alexander J M; Labinger, Jay A; Bercaw, John E

    2011-01-01

    Trialkylborane additives promote reduction of CO(2) to formate by bis(diphosphine) Ni(II) and Rh(III) hydride complexes. The late transition metal hydrides, which can be formed from dihydrogen, transfer hydride to CO(2) to give a formate-borane adduct. The borane must be of appropriate Lewis acidity: weaker acids do not show significant hydride transfer enhancement, while stronger acids abstract hydride without CO(2) reduction. The mechanism likely involves a pre-equilibrium hydride transfer followed by formation of a stabilizing formate-borane adduct.

  5. Sorption of small molecules in polymeric media

    Science.gov (United States)

    Camboni, Federico; Sokolov, Igor M.

    2016-12-01

    We discuss the sorption of penetrant molecules from the gas phase by a polymeric medium within a model which is very close in spirit to the dual sorption mode model: the penetrant molecules are partly dissolved within the polymeric matrix, partly fill the preexisting voids. The only difference with the initial dual sorption mode situation is the assumption that the two populations of molecules are in equilibrium with each other. Applying basic thermodynamics principles we obtain the dependence of the penetrant concentration on the pressure in the gas phase and find that this is expressed via the Lambert W-function, a different functional form than the one proposed by dual sorption mode model. The Lambert-like isotherms appear universally at low and moderate pressures and originate from the assumption that the internal energy in a polymer-penetrant-void ternary mixture is (in the lowest order) a bilinear form in the concentrations of the three components. Fitting the existing data shows that in the domain of parameters where the dual sorption mode model is typically applied, the Lambert function, which describes the same behavior as the one proposed by the gas-polymer matrix model, fits the data equally well.

  6. Sorption of tylosin on clay minerals.

    Science.gov (United States)

    Zhang, Qian; Yang, Chen; Huang, Weilin; Dang, Zhi; Shu, Xiaohua

    2013-11-01

    The equilibrium sorption of tylosin (TYL) on kaolinite and montmorillonite was measured at different solution pH using batch reactor systems. The results showed that all the sorption isotherms were nonlinear and that the nonlinearity decreased as the solution pH increased for a given clay. At a specific aqueous concentration, the single-point sorption distribution coefficient (KD) of TYL decreased rapidly as the solution pH increased. A speciation-dependent sorption model that accounted for the contributions of the cationic and neutral forms of TYL fit the data well, suggesting that the sorption may be dominated by both ion exchange and hydrophobic interactions. The isotherm data also fit well to a dual mode model that quantifies the contributions of a site-limiting Langmuir component (ion exchange) and a non-specific linear partitioning component (hydrophobic interactions). X-ray diffraction analyses revealed that the interlayers of montmorillonite were expanded due to the uptake of TYL. TYL molecules likely form a monolayer surface coverage.

  7. A quantitative phase field model for hydride precipitation in zirconium alloys: Part II. Modeling of temperature dependent hydride precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Zhihua [The Hong Kong Polytechnic University, Shenzhen Research Institute, Shenzhen (China); PolyU Base (Shenzhen) Limited, Shenzhen (China); Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Hao, Mingjun [The Hong Kong Polytechnic University, Shenzhen Research Institute, Shenzhen (China); Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Guo, Xianghua [State Key Laboratory of Explosion and Safety Science, Beijing Institute of Technology, Beijing 100081 (China); Tang, Guoyi [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Shi, San-Qiang, E-mail: mmsqshi@polyu.edu.hk [The Hong Kong Polytechnic University, Shenzhen Research Institute, Shenzhen (China); PolyU Base (Shenzhen) Limited, Shenzhen (China); Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

    2015-04-15

    A quantitative free energy functional developed in Part I (Shi and Xiao, 2014 [1]) was applied to model temperature dependent δ-hydride precipitation in zirconium in real time and real length scale. At first, the effect of external tensile load on reorientation of δ-hydrides was calibrated against experimental observations, which provides a modification factor for the strain energy in free energy formulation. Then, two types of temperature-related problems were investigated. In the first type, the effect of temperature transient was studied by cooling the Zr–H system at different cooling rates from high temperature while an external tensile stress was maintained. At the end of temperature transients, the average hydride size as a function of cooling rate was compared to experimental data. In the second type, the effect of temperature gradients was studied in a one or two dimensional temperature field. Different boundary conditions were applied. The results show that the hydride precipitation concentrated in low temperature regions and that it eventually led to the formation of hydride blisters in zirconium. A brief discussion on how to implement the hysteresis of hydrogen solid solubility on hydride precipitation and dissolution in the developed phase field scheme is also presented.

  8. Designing metal hydride complexes for water splitting reactions: a molecular electrostatic potential approach.

    Science.gov (United States)

    Sandhya, K S; Suresh, Cherumuttathu H

    2014-08-28

    The hydridic character of octahedral metal hydride complexes of groups VI, VII and VIII has been systematically studied using molecular electrostatic potential (MESP) topography. The absolute minimum of MESP at the hydride ligand (Vmin) and the MESP value at the hydride nucleus (VH) are found to be very good measures of the hydridic character of the hydride ligand. The increasing/decreasing electron donating feature of the ligand environment is clearly reflected in the increasing/decreasing negative character of Vmin and VH. The formation of an outer sphere metal hydride-water complex showing the HH dihydrogen interaction is supported by the location and the value of Vmin near the hydride ligand. A higher negative MESP suggested lower activation energy for H2 elimination. Thus, MESP features provided a way to fine-tune the ligand environment of a metal-hydride complex to achieve high hydridicity for the hydride ligand. The applicability of an MESP based hydridic descriptor in designing water splitting reactions is tested for group VI metal hydride model complexes of tungsten.

  9. Kinetic, equilibrium and thermodynamic modelling of the sorption of ...

    African Journals Online (AJOL)

    Kinetic, equilibrium and thermodynamic modelling of the sorption of metals ... Batch sorption studies were conducted to assess the potential of a ... negative Ea values, indicating their preference to bind to low-energy sites. ... Article Metrics.

  10. Chemical Hydride Slurry for Hydrogen Production and Storage

    Energy Technology Data Exchange (ETDEWEB)

    McClaine, Andrew W

    2008-09-30

    The purpose of this project was to investigate and evaluate the attractiveness of using a magnesium chemical hydride slurry as a hydrogen storage, delivery, and production medium for automobiles. To fully evaluate the potential for magnesium hydride slurry to act as a carrier of hydrogen, potential slurry compositions, potential hydrogen release techniques, and the processes (and their costs) that will be used to recycle the byproducts back to a high hydrogen content slurry were evaluated. A 75% MgH2 slurry was demonstrated, which was just short of the 76% goal. This slurry is pumpable and storable for months at a time at room temperature and pressure conditions and it has the consistency of paint. Two techniques were demonstrated for reacting the slurry with water to release hydrogen. The first technique was a continuous mixing process that was tested for several hours at a time and demonstrated operation without external heat addition. Further work will be required to reduce this design to a reliable, robust system. The second technique was a semi-continuous process. It was demonstrated on a 2 kWh scale. This system operated continuously and reliably for hours at a time, including starts and stops. This process could be readily reduced to practice for commercial applications. The processes and costs associated with recycling the byproducts of the water/slurry reaction were also evaluated. This included recovering and recycling the oils of the slurry, reforming the magnesium hydroxide and magnesium oxide byproduct to magnesium metal, hydriding the magnesium metal with hydrogen to form magnesium hydride, and preparing the slurry. We found that the SOM process, under development by Boston University, offers the lowest cost alternative for producing and recycling the slurry. Using the H2A framework, a total cost of production, delivery, and distribution of $4.50/kg of hydrogen delivered or $4.50/gge was determined. Experiments performed at Boston

  11. Hydriding and Dehydriding Properties of Zinc Borohydride, Nickel, and Titanium-Added Magnesium Hydride

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Young Jun; Kwon, Sung Nam; Song, Myoung Youp [Chonbuk National University, Jeonju (Korea, Republic of)

    2015-11-15

    A Zn(BH{sub 4}){sub 2} sample was prepared by milling ZnCl{sub 2} and NaBH{sub 4} in a planetary ball mill under Ar gas. This sample contained NaCl. Then, 90 wt% MgH{sub 2}-5 wt% Zn(BH{sub 4}){sub 2}-2.5 wt% Ni-2.5 wt% Ti samples [named 90MgH{sub 2}-5Zn(BH{sub 4}){sub 2}-2.5Ni-2.5Ti] were prepared by milling in a planetary ball mill under H{sub 2} gas. The hydrogen absorption and release properties of the prepared samples were investigated. In particular, the variations of the initial hydriding and dehydriding rates with temperature were examined. SEM micrographs and XRD patterns of 90MgH{sub 2}-5Zn(BH{sub 4}){sub 2}-2.5Ni-2.5Ti after reactive mechanical grinding and after hydriding-dehydriding were also studied. Particle size distributions and BET specific surface areas of 90MgH{sub 2}-5Zn(BH{sub 4}){sub 2}-2.5Ni-2.5Ti after reactive mechanical grinding and after 11 hydriding-dehydriding cycles were analyzed. The 90MgH{sub 2}-5Zn(BH{sub 4}){sub 2}-2.5Ni-2.5Ti had an effective hydrogen storage capacity (the quantity of hydrogen absorbed for 60 min) of near 5 wt% (4.91 wt% at 593 K).

  12. Sorption Properties of Some Romanian Gingerbread

    Directory of Open Access Journals (Sweden)

    Tulbure Anca

    2014-06-01

    Full Text Available Water activity of gingerbread is very important for keeping the product freshness and shelf life. Water activity is influenced by composition, water content and temperature. The water content of gingerbread could vary according with storage condition. i.e. rH. 11 gingerbread samples were analysed. The water content and water activity lies between 7.0 and 12.6% and respectively 0.590 and 0.715. The sorption isotherms were determined at 30°C by gravimetric method. The moisture sorption is influenced by composition, especially sweeteners and humectants. Honey and invert sugar have the same impact on gingerbread higroscopicity.

  13. A Sorption Hysteresis Model For Cellulosic Materials

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Damkilde, Lars

    2006-01-01

    The equilibrium concentration of adsorbed water in cellulosic materials is dependent on the history of the variations of vapor pressure in the ambient air, i.e. sorption hysteresis. Existing models to describe this phenomenon such as the independent domain theory have numerical drawbacks and....../or imply accounting for the entire history variations of every material point. This paper presents a sorption hysteresis model based on a state formulation and expressed in closed-form solutions, which makes it suitable for implementation into a numerical method....

  14. Gas Sorption and Storage Properties of Calixarenes

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Rahul S.; Banerjee, Debasis; Atwood, Jerry L.; Thallapally, Praveen K.

    2016-12-01

    Calixarenes, a class of organic macrocyclic molecules have shown interesting gas sorption properties towards industrially important gases such as carbon di-oxide, hydrogen, methane and acetylene. These macrocycles are involved in weak van der Waals interaction to form multidimensional supramolecular frameworks. The gas-diffusion and subsequent sorption occurs due to a cooperative behavior between neighboring macrocycles. Furthermore, the flexibility at the upper rim functional group also plays a key role in the overall gas uptake of calixarene. In this book chapter, we give a brief account of interaction and diffusion of gases in calixarene and selected derivatives.

  15. Performance Prediction and Experimental Investigations on Integral Pulse Tube Cryocooler for 15 W at 70 K Using Indigenously Developed Linear Compressor

    Science.gov (United States)

    Gawali, B. S.; Narayankhedkar, K. G.

    2006-04-01

    Theoretical model based on cyclic analysis has been extended to design the integral pulse tube cryocooler. Cryocooler is developed to match with the indigenously developed opposed piston linear compressor of 30 cc swept volume. The design is carried for the Stirling type Pulse Tube cryocooler to develop 15 W at 70 K. The Pulse Tube cryocooler has been developed with due attention to the heat exchangers and regenerator. Experimental investigations have been carried out for study of the effect of pulse tube aspect ratio and to confirm the consistency of the model and suitability of the linear compressor. Experimental investigation confirmed consistent performance of the linear compressor as well as the Pulse Tube cryocooler.

  16. An improved experimental and regression methodology for sorption isotherms

    NARCIS (Netherlands)

    Quirijns, E.J.; Boxtel, van A.J.B.; Loon, van W.K.P.; Straten, van G.

    2005-01-01

    Sorption isotherms of corn and starch cylinders with immobilised catalase are experimentally determined at different temperatures for use in drying models in optimal control studies. This application of the sorption isotherm requires an accurate prediction of the sorption data at different temperatu

  17. Sorption induced relaxations during water diffusion in S-PEEK

    NARCIS (Netherlands)

    Potreck, Jens; Uyar, Fuat; Sijbesma, Hylke; Nijmeijer, Kitty; Stamatialis, Dimitris; Wessling, Matthias

    2009-01-01

    This paper presents an analysis of the sorption kinetics of water vapor and liquid water in the glassy polymer sulfonated poly(ether ether ketone) (S-PEEK). Sorption isotherms are determined experimentally using a gravimetric sorption balance, and the relative contributions of Fickian diffusion and

  18. Hydrogen storage as a hydride. Citations from the International Aerospace Abstracts data base

    Science.gov (United States)

    Zollars, G. F.

    1980-01-01

    These citations from the international literature concern the storage of hydrogen in various metal hydrides. Binary and intermetallic hydrides are considered. Specific alloys discussed are iron titanium, lanthanium nickel, magnesium copper and magnesium nickel among others.

  19. Hydrogen storage as a hydride. Citations from the International Aerospace Abstracts data base

    Science.gov (United States)

    Zollars, G. F.

    1980-01-01

    These citations from the international literature concern the storage of hydrogen in various metal hydrides. Binary and intermetallic hydrides are considered. Specific alloys discussed are iron titanium, lanthanium nickel, magnesium copper and magnesium nickel among others.

  20. Numerical simulation and performance test of metal hydride hydrogen storage system

    Directory of Open Access Journals (Sweden)

    Tzu-Hsiang Yen, Bin-Hao Chen, Bao-Dong Chen

    2011-05-01

    Full Text Available Metal hydride reactors are widely used in many industrial applications, such as hydrogen storage, thermal compression, heat pump, etc. According to the research requirement of metal hydride hydrogen storage, the thermal analyses have been implemented in the paper. The metal hydride reaction beds are considered as coupled cylindrical tube modules which combine the chemical absorption and desorption in metal hydride. The model is then used metal hydride LaNi5 as an example to predict the performance of metal hydride hydrogen storage devices, such as the position of hydration front and the thermal flux. Under the different boundary condition the characteristics of heat transfer and mass transfer in metal hydride have influence on the hydrogen absorption and desorption. The researches revealed that the scroll design can improve the temperature distribution in the reactor and the porous tube for directing hydrogen can increase the penetration depth of hydride reaction to decrease the hydrogen absorption time.

  1. Micro-scale fracture experiments on zirconium hydrides and phase boundaries

    Science.gov (United States)

    Chan, H.; Roberts, S. G.; Gong, J.

    2016-07-01

    Fracture properties of micro-scale zirconium hydrides and phase boundaries were studied using microcantilever testing methods. FIB-machined microcantilevers were milled on cross-sectional surfaces of hydrided samples, with the most highly-stressed regions within the δ-hydride film, within the α-Zr or along the Zr-hydride interface. Cantilevers were notched using the FIB and then tested in bending using a nanoindenter. Load-displacement results show that three types of cantilevers have distinct deformation properties. Zr cantilevers deformed plastically. Hydride cantilevers fractured after a small amount of plastic flow; the fracture toughness of the δ-hydride was found to be 3.3 ± 0.4 MPam1/2 and SEM examination showed transgranular cleavage on the fracture surfaces. Cantilevers notched at the Zr-hydride interface developed interfacial voids during loading, at loads considerably lower than that which initiate brittle fracture of hydrides.

  2. The design and fabrication of a reverse Brayton cycle cryocooler system for the high temperature superconductivity cable cooling

    Science.gov (United States)

    Park, Jae Hong; Kwon, Yong Ha; Kim, Young Soo

    2005-01-01

    A high temperature superconductivity cable must be cooled below the nitrogen liquefaction temperature to apply the cable to power generation and transmission systems under superconducting state. To maintain the superconducting state, a reliable cryocooler system is also required. The design and fabrication of a cryocooler system have been performed with a reverse Brayton cycle using neon gas as a refrigerant. The system consists of a compressor, a recuperator, a cold-box, and control valves. The design of the system is made to have 1 kW cooling capacity. The heat loss through multilayer insulators is calculated. Conduction heat loss is about 7 W through valves and access ports and radiation heat loss is about 18 W on the surface of a cryocooler. The design factors are discussed in detail.

  3. Numerical Study of a 10 K Two Stage Pulse Tube Cryocooler with Precooling Inside the Pulse Tube

    Science.gov (United States)

    Xiaomin, Pang; Xiaotao, Wang; Wei, Dai; Jianyin, Hu; Ercang, Luo

    2017-02-01

    High efficiency cryocoolers working below 10 K have many applications such as cryo-pump, superconductor cooling and cryogenic electronics. This paper presents a thermally coupled two-stage pulse tube cryocooler system and its numeric analysis. The simulation results indicate that temperature distribution in the pulse tube has a significant impact on the system performance. So a precooling heat exchanger is put inside the second stage pulse tube for a deep investigation on its influence on the system performance. The influences of operating parameters such as precooling temperature, location of the precooling heat exchanger are discussed. Comparison of energy losses apparently show the advantages of the configuration which leads to an improvement on the efficiency. Finally, the cryocooler is predicted to be able to reach a relative Carnot efficiency of 10.7% at 10 K temperature.

  4. Study of annealing effects on structural and sorption properties of low energy mechanically alloyed AB{sub 5}'s

    Energy Technology Data Exchange (ETDEWEB)

    Talaganis, B.A., E-mail: talaganb@ib.cnea.gov.a [Instituto Balseiro (UNCu) and CNEA, Av. Bustillo Km. 9.5 (R8402AGP), Bariloche, Rio Negro (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Esquivel, M.R. [Instituto Balseiro (UNCu) and CNEA, Av. Bustillo Km. 9.5 (R8402AGP), Bariloche, Rio Negro (Argentina); Centro Atomico Bariloche, Comision Nacional de Energia Atomica (CNEA) (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); C.R.U.B.-U.N.Co. Quintral 1250 (R8400FRF), Bariloche, Rio Negro (Argentina); Meyer, G. [Instituto Balseiro (UNCu) and CNEA, Av. Bustillo Km. 9.5 (R8402AGP), Bariloche, Rio Negro (Argentina); Centro Atomico Bariloche, Comision Nacional de Energia Atomica (CNEA) (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina)

    2010-04-16

    In this work, various AB{sub 5}'s were mechanically alloyed using a low energy mill until final or completion milling stages were reached. This process leaves micro- and nano-structured materials with highly distorted microstructures. Then, further annealing is needed to obtain an intermetallic suitable for hydrogen thermal compression process. After milling, the samples were annealed and analyzed by X-ray diffraction and Differential Scanning Calorimetry. Hydriding properties were studied using volumetric methods. After annealing at 200 {sup o}C for 24 h no changes occur in neither structural nor hydriding properties. For samples annealed at 400 {sup o}C, relaxation effects of the structure were observed. It occurs due to the release of strain produced by annealing on the microstructure. It leads to the improvements in both structural and hydriding properties. Strong recrystallization effect was present between 400 and 600 {sup o}C. At 600 {sup o}C, the main improvements were larger crystallite size, lower strain values and pressure-composition isotherms with well-defined plateaus. Despite this behavior, no evidence of crystallization was observed by Differential Scanning Calorimetry measurements from room temperature up to 500 {sup o}C. These topics, the amount of energy supplied during mechanical alloying and the correlation between the structural and sorption properties are discussed according to the governing mechanisms of recrystallization observed in each temperature range. From these results, an improved synthesis-thermal treatment method is outlined.

  5. Hydration and sorption characteristics of a polyfunctional weak-base anion exchanger after the sorption of vanillin and ethylvanillin

    Science.gov (United States)

    Rodionova, D. O.; Voronyuk, I. V.; Eliseeva, T. V.

    2016-07-01

    Features of the sorption of substituted aromatic aldehydes by a weak-base anion exchanger under equilibrium conditions are investigated using vanillin and ethylvanillin as examples. Analysis of the sorption isotherms of carbonyl compounds at different temperatures allows us to calculate the equilibrium characteristics of their sorption and assess the entropy and enthalpy contributions to the energy of the process. Hydration characteristics of the macroporous weak-base anion exchanger before and after the sorption of aromatic aldehydes are compared.

  6. Investigation of Cracked Lithium Hydride Reactor Vessels

    Energy Technology Data Exchange (ETDEWEB)

    bird, e.l.; mustaleski, t.m.

    1999-06-01

    Visual examination of lithium hydride reactor vessels revealed cracks that were adjacent to welds, most of which were circumferentially located in the bottom portion of the vessels. Sections were cut from the vessels containing these cracks and examined by use of the metallograph, scanning electron microscope, and microprobe to determine the cause of cracking. Most of the cracks originated on the outer surface just outside the weld fusion line in the base material and propagated along grain boundaries. Crack depths of those examined sections ranged from {approximately}300 to 500 {micro}m. Other cracks were reported to have reached a maximum depth of 1/8 in. The primary cause of cracking was the creation of high tensile stresses associated with the differences in the coefficients of thermal expansion between the filler metal and the base metal during operation of the vessel in a thermally cyclic environment. This failure mechanism could be described as creep-type fatigue, whereby crack propagation may have been aided by the presence of brittle chromium carbides along the grain boundaries, which indicates a slightly sensitized microstructure.

  7. Transition-Metal Hydride Radical Cations.

    Science.gov (United States)

    Hu, Yue; Shaw, Anthony P; Estes, Deven P; Norton, Jack R

    2016-08-10

    Transition-metal hydride radical cations (TMHRCs) are involved in a variety of chemical and biochemical reactions, making a more thorough understanding of their properties essential for explaining observed reactivity and for the eventual development of new applications. Generally, these species may be treated as the ones formed by one-electron oxidation of diamagnetic analogues that are neutral or cationic. Despite the importance of TMHRCs, the generally sensitive nature of these complexes has hindered their development. However, over the last four decades, many more TMHRCs have been synthesized, characterized, isolated, or hypothesized as reaction intermediates. This comprehensive review focuses on experimental studies of TMHRCs reported through the year 2014, with an emphasis on isolated and observed species. The methods used for the generation or synthesis of TMHRCs are surveyed, followed by a discussion about the stability of these complexes. The fundamental properties of TMHRCs, especially those pertaining to the M-H bond, are described, followed by a detailed treatment of decomposition pathways. Finally, reactions involving TMHRCs as intermediates are described.

  8. In situ X-ray Raman spectroscopy study of the hydrogen sorption properties of lithium borohydride nanocomposites.

    Science.gov (United States)

    Miedema, Piter S; Ngene, Peter; van der Eerden, Ad M J; Sokaras, Dimosthenis; Weng, Tsu-Chien; Nordlund, Dennis; Au, Yuen S; de Groot, Frank M F

    2014-11-07

    Nanoconfined alkali metal borohydrides are promising materials for reversible hydrogen storage applications, but the characterization of hydrogen sorption in these materials is difficult. Here we show that with in situ X-ray Raman spectroscopy (XRS) we can track the relative amounts of intermediates and final products formed during de- and re-hydrogenation of nanoconfined lithium borohydride (LiBH4) and therefore we can possibly identify the de- and re-hydrogenation pathways. In the XRS of nanoconfined LiBH4 at different points in the de- and re-hydrogenation, we identified phases that lead to the conclusion that de- and re-hydrogenation pathways in nanoconfined LiBH4 are different from bulk LiBH4: intercalated lithium (LiCx), boron and lithium hydride were formed during de-hydrogenation, but as well Li2B12H12 was observed indicating that there is possibly some bulk LiBH4 present in the nanoconfined sample LiBH4-C as prepared. Surprisingly, XRS revealed that the de-hydrogenated products of the LiBH4-C nanocomposites can be partially rehydrogenated to about 90% of Li2B12H12 and 2-5% of LiBH4 at a mild condition of 1 bar H2 and 350 °C. This suggests that re-hydrogenation occurs via the formation of Li2B12H12. Our results show that XRS is an elegant technique that can be used for in and ex situ study of the hydrogen sorption properties of nanoconfined and bulk light-weight metal hydrides in energy storage applications.

  9. Comparison of the interactions in the rare gas hydride and Group 2 metal hydride anions.

    Science.gov (United States)

    Harris, Joe P; Manship, Daniel R; Breckenridge, W H; Wright, Timothy G

    2014-02-28

    We study both the rare gas hydride anions, RG-H(-) (RG = He-Rn) and Group 2 (Group IIa) metal hydride anions, MIIaH(-) (MIIa = Be-Ra), calculating potential energy curves at the CCSD(T) level with augmented quadruple and quintuple basis sets, and extrapolating the results to the basis set limit. We report spectroscopic parameters obtained from these curves; additionally, we study the Be-He complex. While the RG-H(-) and Be-He species are weakly bound, we show that, as with the previously studied BeH(-) and MgH(-) species, the other MIIaH(-) species are strongly bound, despite the interactions nominally also being between two closed shell species: M(ns(2)) and H(-)(1s(2)). We gain insight into the interactions using contour plots of the electron density changes and population analyses. For both series, the calculated dissociation energy is significantly less than the ion/induced-dipole attraction term, confirming that electron repulsion is important in these species; this effect is more dramatic for the MIIaH(-) species than for RG-H(-). Our analyses lead us to conclude that the stronger interaction in the case of the MIIaH(-) species arises from sp and spd hybridization, which allows electron density on the MIIa atom to move away from the incoming H(-).

  10. Multidimensional simulations of hydrides during fuel rod lifecycle

    Science.gov (United States)

    Stafford, D. S.

    2015-11-01

    In light water reactor fuel rods, waterside corrosion of zirconium-alloy cladding introduces hydrogen into the cladding, where it is slightly soluble. When the solubility limit is reached, the hydrogen precipitates into crystals of zirconium hydride which decrease the ductility of the cladding and may lead to cladding failure during dry storage or transportation events. The distribution of the hydride phase and the orientation of the crystals depend on the history of the spatial temperature and stress profiles in the cladding. In this work, we have expanded the existing hydride modeling capability in the BISON fuel performance code with the goal of predicting both global and local effects on the radial, azimuthal and axial distribution of the hydride phase. We compare results from 1D simulations to published experimental data. We demonstrate the new capability by simulating in 2D a fuel rod throughout a lifecycle that includes irradiation, short-term storage in the spent fuel pool, drying, and interim storage in a dry cask. Using the 2D simulations, we present qualitative predictions of the effects of the inter-pellet gap and the drying conditions on the growth of a hydride rim.

  11. The effect of stress state on zirconium hydride reorientation

    Science.gov (United States)

    Cinbiz, Mahmut Nedim

    Prior to storage in a dry-cask facility, spent nuclear fuel must undergo a vacuum drying cycle during which the spent fuel rods are heated up to elevated temperatures of ≤ 400°C to remove moisture the canisters within the cask. As temperature increases during heating, some of the hydride particles within the cladding dissolve while the internal gas pressure in fuel rods increases generating multi-axial hoop and axial stresses in the closed-end thin-walled cladding tubes. As cool-down starts, the hydrogen in solid solution precipitates as hydride platelets, and if the multiaxial stresses are sufficiently large, the precipitating hydrides reorient from their initial circumferential orientation to radial orientation. Radial hydrides can severely embrittle the spent nuclear fuel cladding at low temperature in response to hoop stress loading. Because the cladding can experience a range of stress states during the thermo-mechanical treatment induced during vacuum drying, this study has investigated the effect of stress state on the process of hydride reorientation during controlled thermo-mechanical treatments utilizing the combination of in situ X-ray diffraction and novel mechanical testing analyzed by the combination of metallography and finite element analysis. The study used cold worked and stress relieved Zircaloy-4 sheet containing approx. 180 wt. ppm hydrogen as its material basis. The failure behavior of this material containing radial hydrides was also studied over a range of temperatures. Finally, samples from reactor-irradiated cladding tubes were examined by X-ray diffraction using synchrotron radiation. To reveal the stress state effect on hydride reorientation, the critical threshold stress to reorient hydrides was determined by designing novel mechanical test samples which produce a range of stress states from uniaxial to "near-equibiaxial" tension when a load is applied. The threshold stress was determined after thermo-mechanical treatments by

  12. Sodium-based hydrides for thermal energy applications

    Science.gov (United States)

    Sheppard, D. A.; Humphries, T. D.; Buckley, C. E.

    2016-04-01

    Concentrating solar-thermal power (CSP) with thermal energy storage (TES) represents an attractive alternative to conventional fossil fuels for base-load power generation. Sodium alanate (NaAlH4) is a well-known sodium-based complex metal hydride but, more recently, high-temperature sodium-based complex metal hydrides have been considered for TES. This review considers the current state of the art for NaH, NaMgH3- x F x , Na-based transition metal hydrides, NaBH4 and Na3AlH6 for TES and heat pumping applications. These metal hydrides have a number of advantages over other classes of heat storage materials such as high thermal energy storage capacity, low volume, relatively low cost and a wide range of operating temperatures (100 °C to more than 650 °C). Potential safety issues associated with the use of high-temperature sodium-based hydrides are also addressed.

  13. Design of a 2 Slot VLPC Cryostat Cooled by a Cryocooler

    Energy Technology Data Exchange (ETDEWEB)

    Rucinski, Russell A.; /Fermilab

    2004-04-22

    The conceptual design and preliminary engineering calculations have been completed for a two cassette cryostat. This report summarizes the design. A cryocooler is permanently mounted in the center of a stainless steel, 0.75 inch thick top lid. The cryocooler sits upon a spacer which raises the cooling stage elevations to favorably match the cassette heat intercept elevations. The top lid (32.0-inch outside diameter) mates to a 24-inch pipe size flange with o-ring. The 24-inch pipe size vacuum vessel with end plate has a minimum internal depth of 16-inch to give adequate clearance for the depth of the cryocooler and multilayer insulation blankets. Support stand legs elevate the container to a convenient height and allow for placement of the AFE power supply underneath. Two cassette slots are located on either side of the cryocooler. The slots are positioned parallel to each other, 10.5-inch center to center (6 standard cassette slot widths) so that the standard 8 slot AFE backplane can be used. The slot opening through the lid is approximately 1.422-inch x 16.782-inch. A 0.016-inch thick titanium (Ti-6AI-4V) envelope with sealing lip is inserted through lid and defines the gas helium boundary that the VLPC cassette resides. The internal dimensions of the titanium envelope are 1.390-inch x 16.75-inch x 10.531-inch deep. When the cassette is inserted the clearances will be 0.015-inch on the long side, 0.063-inch on the short side, and 0.032-inch at the bottom. The cassette gasket seals against the top lip of the titanium envelope. A soft gasket or thin vacuum sealant tape seals the underside of the titanium envelope to the top surface of the lid. A clamping hold down bar may be necessary to make this vacuum seal. Gas helium for the cassette space is supplied through a fitting and port that is added to the cassette bulkhead assembly. This is the only modification necessary the standard D-Zero cassette. Evacuation and backfilling and then stagnant positive pressure are

  14. Sorption Recovery of Gold Thiosulphate Complexes

    Institute of Scientific and Technical Information of China (English)

    A.G.Kholmogorov; O.N.Kononova; 等

    2002-01-01

    The gold sorption from thiosulphate solutions on carbon sorbents and on anion exchangers was studied. It was shown that the anion exchangers AV-17-10P and AP-100 are the most effective and selective at pH=5-8. These anion exchangers can be recommended for the gold recovery from the industrial solutions.

  15. SORPTION PROPERTIES OF PLANT POLYSACCHARIDE COMPLEXES

    Directory of Open Access Journals (Sweden)

    L. E. Glagoleva

    2012-01-01

    Full Text Available The article presents information on the laws of the sorption of water to grow-negative polysaccharide complexes of the pumpkin and briar, deter-mined the rate constant of swelling as a function of temperature and pH, the maximum degree of swelling and limit the time to achieve it.

  16. Sorption of metals by Chlorobium spp.

    Science.gov (United States)

    Garcia-Gil, J; Borrego, C

    1997-12-01

    The capacity of two species of green phototrophic sulfur bacteria, Chlorobium limicola and C. phaeobacteroides, to sorb several metal ions (Mn2+, Fe2+, Ni2+, Cu2+, Zn2+, Cd2+ and Pb2+) has been tested in laboratory batch cultures at increasing concentrations up to 2,000 mumol/l. Except for nickel--which was not sorbed to bacterial cells--the rest of metals tested were bound in a fast and passive process, which was mathematically described by means of Freundlich isotherms models. The sorption capacity of the two species studied were found to be dependent on the metal involved, whereas no differences were observed in the sorption intensity, suggesting that in all cases the sorption process proceeds in a similar way. Further, the comparison of the sorption intensity values as well as the metal recovery index (Ri), for both species, revealed that C. phaeobacteroides was more efficient that C. limicola to attach metal ions. The ecological significance of this ability in the water column of some stratified lakes, where coinciding maxima of ferrous iron and green photosynthetic sulfur bacteria are frequently found, is discussed.

  17. A Sorption Hysteresis Model For Cellulosic Materials

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Damkilde, Lars

    2006-01-01

    The equilibrium concentration of adsorbed water in cellulosic materials is dependent on the history of the variations of vapor pressure in the ambient air, i.e. sorption hysteresis. Existing models to describe this phenomenon such as the independent domain theory have numerical drawbacks and/or i...

  18. Enhancement of the bentonite sorption properties.

    Science.gov (United States)

    Mockovciaková, Annamária; Orolínová, Zuzana; Skvarla, Jirí

    2010-08-15

    The almost monomineral fraction of bentonite rock-montmorillonite was modified by magnetic particles to enhance its sorption properties. The method of clay modification consists in the precipitation of magnetic nanoparticles, often used in preparing of ferrofluids, on the surface of clay. The influence of the synthesis temperature (20 and 85 degrees C) and the weight ratio of bentonite/iron oxides (1:1 and 5:1) on the composite materials properties were investigated. The obtained materials were characterized by the X-ray diffraction method and Mössbauer spectroscopy. Changes in the surface and pore properties of the magnetic composites were studied by the low nitrogen adsorption method and the electrokinetic measurements. The natural bentonite and magnetic composites were used in sorption experiments. The sorption of toxic metals (zinc, cadmium and nickel) from the model solutions was well described by the linearized Langmuir and Freundlich sorption model. The results show that the magnetic bentonite is better sorbent than the unmodified bentonite if the initial concentration of studied metals is very low. Copyright 2010 Elsevier B.V. All rights reserved.

  19. Sorption of pesticides to aquifer minerals

    DEFF Research Database (Denmark)

    Clausen, Liselotte; Fabricius, Ida Lykke

    2000-01-01

    This paper summarizes results from a work were the sorption of five pesticides on seven minerals were studied in order to quantify the adsorption to different mineral surfaces. Investigated mineral phases are: quartz, calcite, kaolinite, a-alumina, and three iron oxides (2-line ferrihydrite, goet...

  20. High performance fiber-coupled NbTiN superconducting nanowire single photon detectors with Gifford-McMahon cryocooler

    CERN Document Server

    Miki, Shigehito; Terai, Hirotaka; Wang, Zhen

    2013-01-01

    We present high performance fiber-coupled niobium titanium nitride superconducting nanowire single photon detectors fabricated on thermally oxidized silicon substrates. The best device showed a system detection efficiency (DE) of 74%, dark count rate of 100 c/s, and full width at half maximum timing jitter of 68 ps under a bias current of 18.0 uA with a practical Gifford-McMahon cryocooler system. We also introduced six detectors into the cryocooler and confirmed that the system DE of all detectors was higher than 63% at the dark count rate of 100 c/s.

  1. Development of 0.5-5 W, 10K Reverse Brayton Cycle Cryocoolers - Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Doty, F. D.; Boman, A.; Arnold, S.; Spitzmesser, J. B.; Jones, D.; McCree, D.; Hacker, L. J.

    2001-10-15

    Miniature cryocoolers for the 8-30 K range are needed to provide 0.5-5 w of cooling to high sensitivity detectors (for long-wave-length IR, magnetism, mm-wave, X-ray, dark matter, and possibly y-ray detection) while maintaining low mass, ultra-low vibration, and good efficiency. This project presents a new approach to eliminating the problems normally encountered in efforts to build low-vibration, fieldable, miniature cryocoolers. Using the reverse Brayton Cycle (RBC), the approach applies and expands on existing spinner technology previously used only in Nuclear Magnetic Resonance (NMR) probes.

  2. High performance fiber-coupled NbTiN superconducting nanowire single photon detectors with Gifford-McMahon cryocooler.

    Science.gov (United States)

    Miki, Shigehito; Yamashita, Taro; Terai, Hirotaka; Wang, Zhen

    2013-04-22

    We present high performance fiber-coupled niobium titanium nitride superconducting nanowire single photon detectors fabricated on thermally oxidized silicon substrates. The best device showed a system detection efficiency (DE) of 74%, dark count rate of 100 c/s, and full width at half maximum timing jitter of 68 ps under a bias current of 18.0 μA with a practical Gifford-McMahon cryocooler system. We also introduced six detectors into the cryocooler and confirmed that the system DE of all detectors was higher than 67% at the dark count rate of 100 c/s.

  3. Comparison of Hydrogen Elimination from Molecular Zinc and Magnesium Hydride Clusters

    NARCIS (Netherlands)

    Intemann, J.; Sirsch, Peter; Harder, Sjoerd

    2014-01-01

    In analogy to the previously reported tetranuclear magnesium hydride cluster with a bridged dianionic bis-beta-diketiminate ligand, a related zinc hydride cluster has been prepared. The crystal structures of these magnesium and zinc hydride complexes are similar: the metal atoms are situated at the

  4. Use of triammonium salt of aurin tricarboxylic acid as risk mitigant for aluminum hydride

    Science.gov (United States)

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

    2017-08-08

    A process and a resulting product by process of an aluminum hydride which is modified with by physically combining in a ball milling process an aluminum hydride with a triammonium salt of aurin tricarboxylic acid. The resulting product is an aluminum hydride which is resistant to air, ambient moisture, and liquid water while maintaining useful hydrogen storage and release kinetics.

  5. Comparison of Hydrogen Elimination from Molecular Zinc and Magnesium Hydride Clusters

    NARCIS (Netherlands)

    Intemann, J.; Sirsch, Peter; Harder, Sjoerd

    2014-01-01

    In analogy to the previously reported tetranuclear magnesium hydride cluster with a bridged dianionic bis-beta-diketiminate ligand, a related zinc hydride cluster has been prepared. The crystal structures of these magnesium and zinc hydride complexes are similar: the metal atoms are situated at the

  6. Investigation of metal hydride materials as hydrogen reservoirs for metal-hydrogen batteries

    Science.gov (United States)

    ONISCHAK

    1976-01-01

    The performance and suitability of various metal hydride materials were examined for use as possible hydrogen storage reservoirs for secondary metal-hydrogen batteries. Lanthanum pentanickel hydride appears as a probable candidate in terms of stable hydrogen supply under feasible thermal conditions. A kinetic model describing the decomposition rate data of the hydride has been developed.

  7. The structural characterization and H2 sorption properties of carbon-supported Mg1-xNix nanocrystallites

    Science.gov (United States)

    Bogerd, René; Adelhelm, Philipp; Meeldijk, Johannes H.; de Jong, Krijn P.; de Jongh, Petra E.

    2009-05-01

    Magnesium (hydride) is a promising system for the reversible on-board storage of hydrogen, but suffers from slow sorption kinetics and a high thermodynamic stability of the hydride. We explored a combined approach to tackle these problems: nanosizing and carbon-supporting the magnesium, and doping it with nickel. Samples were prepared by melt infiltration with magnesium of nanoporous carbon onto which 1-12 wt% nickel nanoparticles had been predeposited. For loadings up to 15 wt% MgH2, 10-30 nm crystallites with different compositions were formed inside the porous carbon, each giving a specific H2 desorption signature. Surprisingly, higher Mg loadings resulted in more homogeneously mixed samples, which was due to the facilitated wetting of the carbon with the magnesium due to the presence of nickel. Hydrogen release temperatures close to that of Mg2NiH4 were observed for high MgH2 loadings (50 wt%) and small amounts of Ni (Mg0.95Ni0.05). The favourable H2 desorption properties could mainly be attributed to excellent kinetics due to the efficient mixing of magnesium, nickel and carbon on the nanoscale.

  8. The structural characterization and H(2) sorption properties of carbon-supported Mg(1-x)Nix nanocrystallites.

    Science.gov (United States)

    Bogerd, René; Adelhelm, Philipp; Meeldijk, Johannes H; de Jong, Krijn P; de Jongh, Petra E

    2009-05-20

    Magnesium (hydride) is a promising system for the reversible on-board storage of hydrogen, but suffers from slow sorption kinetics and a high thermodynamic stability of the hydride. We explored a combined approach to tackle these problems: nanosizing and carbon-supporting the magnesium, and doping it with nickel. Samples were prepared by melt infiltration with magnesium of nanoporous carbon onto which 1-12 wt% nickel nanoparticles had been predeposited. For loadings up to 15 wt% MgH2, 10-30 nm crystallites with different compositions were formed inside the porous carbon, each giving a specific H2 desorption signature. Surprisingly, higher Mg loadings resulted in more homogeneously mixed samples, which was due to the facilitated wetting of the carbon with the magnesium due to the presence of nickel. Hydrogen release temperatures close to that of Mg2NiH4 were observed for high MgH2 loadings (50 wt%) and small amounts of Ni (Mg(0.95)Ni(0.05)). The favourable H2 desorption properties could mainly be attributed to excellent kinetics due to the efficient mixing of magnesium, nickel and carbon on the nanoscale.

  9. Sorption behavior of o-nitrophenol on marine sediment

    Institute of Scientific and Technical Information of China (English)

    YANG Guipeng; WU Ping; KONG Dexin

    2005-01-01

    Systematic study on sorption behavior of o-nitrophenol on marine sediments was conducted.Isotherms of sorption of o-nitrophenol on marine sediments could be described by Freundlich model; and the isotherm of sorption of o-nitrophenol on HCl-treated sediment could be described by Langmuir model. The sorption behavior was affected by various factors including organic carbon content, aqueous solution salinity,temperature, and acidity. The sorption amount of o-nitrophenol increased when salinity and acidity of the aqueous solution increase, but decreased with increasing temperature. Organic carbon content in sediments had apparent effect on the behavior except for HCl-treated sediments.

  10. Implementation of sorption hysteresis in multi-Fickian moisture transport

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Svensson, Staffan

    2007-01-01

    represent this behavior. The multi-Fickian model describes the combined transport of bound water and vapor and their interaction through sorption. The bound-water concentration is also influenced by sorption hysteresis. In the worst case, sorption hysteresis may result in deviations of up to 30......-35% in moisture content. Hence, for a precise moisture content computation, sorption hysteresis must be taken into account. The present paper explains the relation between sorption hysteresis and multi-Fickian moisture transport, and clarifies how models for the two phenomena are coupled. To illustrate...

  11. Implementation of sorption hysteresis in multi-Fickian moisture transport

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Svensson, Staffan

    2007-01-01

    this behavior. The multi-Fickian model describes the combined transport of bound water and vapor and their interaction through sorption. The bound-water concentration is also influenced by sorption hysteresis. In the worst case, sorption hysteresis may result in deviations of up to 30-35% in moisture content....... Hence, for a precise moisture content computation, sorption hysteresis must be taken into account. The present paper explains the relation between sorption hysteresis and multi-Fickian moisture transport, and clarifies how models for the two phenomena are coupled. To illustrate the effects, a finite...

  12. Thermal Vacuum Testing of a Helium Loop Heat Pipe for Large Area Cryocooling

    Science.gov (United States)

    Ku, Jentung; Robinson, Franklin

    2016-01-01

    Future NASA space telescopes and exploration missions require cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks. One device that can potentially be used to provide closed-loop cryocooling is the cryogenic loop heat pipe (CLHP). A CLHP has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A helium CLHP has been tested extensively in a thermal vacuum chamber using a cryocooler as the heat sink to characterize its transient and steady performance and to verify its ability to cool large areas or components in the 3 degrees Kelvin temperature range. The helium CLHP thermal performance test included cool-down from the ambient temperature, startup, capillary limit, heat removal capability, rapid power changes, and long duration steady state operation. The helium CLHP demonstrated robust operation under steady state and transient conditions. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully by simply applying power to both the capillary pump and the evaporator plate without pre-conditioning. It could adapt to a rapid heat load change and quickly reach a new steady state. Heat removal between 10 megawatts and 140 megawatts was demonstrated, yielding a power turn down ratio of 14. When the CLHP capillary limit was exceeded, the loop could resume its normal function by reducing the power to the capillary pump. Steady state operations up to 17 hours at several heat loads were demonstrated. The ability of the helium CLHP to cool large areas was therefore successfully verified.

  13. A study of advanced magnesium-based hydride and development of a metal hydride thermal battery system

    Science.gov (United States)

    Zhou, Chengshang

    Metal hydrides are a group of important materials known as energy carriers for renewable energy and thermal energy storage. A concept of thermal battery based on advanced metal hydrides is studied for heating and cooling of cabins in electric vehicles. The system utilizes a pair of thermodynamically matched metal hydrides as energy storage media. The hot hydride that is identified and developed is catalyzed MgH2 due to its high energy density and enhanced kinetics. TiV0.62Mn1.5, TiMn2, and LaNi5 alloys are selected as the matching cold hydride. A systematic experimental survey is carried out in this study to compare a wide range of additives including transitions metals, transition metal oxides, hydrides, intermetallic compounds, and carbon materials, with respect to their effects on dehydrogenation properties of MgH2. The results show that additives such as Ti and V-based metals, hydride, and certain intermetallic compounds have strong catalytic effects. Solid solution alloys of magnesium are exploited as a way to destabilize magnesium hydride thermodynamically. Various elements are alloyed with magnesium to form solid solutions, including indium and aluminum. Thermodynamic properties of the reactions between the magnesium solid solution alloys and hydrogen are investigated, showing that all the solid solution alloys that are investigated in this work have higher equilibrium hydrogen pressures than that of pure magnesium. Cyclic stability of catalyzed MgH2 is characterized and analyzed using a PCT Sievert-type apparatus. Three systems, including MgH2-TiH 2, MgH2-TiMn2, and MgH2-VTiCr, are examined. The hydrogenating and dehydrogenating kinetics at 300°C are stable after 100 cycles. However, the low temperature (25°C to 150°C) hydrogenation kinetics suffer a severe degradation during hydrogen cycling. Further experiments confirm that the low temperature kinetic degradation can be mainly related the extended hydrogenation-dehydrogenation reactions. Proof

  14. Modeling Fission Product Sorption in Graphite Structures

    Energy Technology Data Exchange (ETDEWEB)

    Szlufarska, Izabela [University of Wisconsin, Madison, WI (United States); Morgan, Dane [University of Wisconsin, Madison, WI (United States); Allen, Todd [University of Wisconsin, Madison, WI (United States)

    2013-04-08

    The goal of this project is to determine changes in adsorption and desorption of fission products to/from nuclear-grade graphite in response to a changing chemical environment. First, the project team will employ principle calculations and thermodynamic analysis to predict stability of fission products on graphite in the presence of structural defects commonly observed in very high- temperature reactor (VHTR) graphites. Desorption rates will be determined as a function of partial pressure of oxygen and iodine, relative humidity, and temperature. They will then carry out experimental characterization to determine the statistical distribution of structural features. This structural information will yield distributions of binding sites to be used as an input for a sorption model. Sorption isotherms calculated under this project will contribute to understanding of the physical bases of the source terms that are used in higher-level codes that model fission product transport and retention in graphite. The project will include the following tasks: Perform structural characterization of the VHTR graphite to determine crystallographic phases, defect structures and their distribution, volume fraction of coke, and amount of sp2 versus sp3 bonding. This information will be used as guidance for ab initio modeling and as input for sorptivity models; Perform ab initio calculations of binding energies to determine stability of fission products on the different sorption sites present in nuclear graphite microstructures. The project will use density functional theory (DFT) methods to calculate binding energies in vacuum and in oxidizing environments. The team will also calculate stability of iodine complexes with fission products on graphite sorption sites; Model graphite sorption isotherms to quantify concentration of fission products in graphite. The binding energies will be combined with a Langmuir isotherm statistical model to predict the sorbed concentration of fission

  15. Sorption of niobium on boreal forest soil

    Energy Technology Data Exchange (ETDEWEB)

    Soederlund, Mervi; Hakanen, Martti; Lehto, Jukka [Helsinki Univ. (Finland). Lab. of Radiochemistry

    2015-07-01

    The sorption of niobium (Nb) was investigated on humus and mineral soil samples taken from various depths of a four-metre deep forest soil pit on Olkiluoto Island, southwestern Finland. Mass distribution coefficients, K{sub d}, were determined in batch sorption tests. The steady state of Nb sorption was observed in the mineral soil samples already after one week of equilibration, and sorption decreased with depth from a very high value of 185000 mL/g at 0.7 m to 54000 mL/g at 3.4 m. The reason behind this decrease is probably the tenfold reduction in the specific surface area of the soil at the same depth range. Distribution coefficients were clearly lower in the humus layer (1000 mL/g). The K{sub d} values determined in pure water at a pH range of 4.7-6.5 were at a high level (above 55000 mL/g), but decreased dramatically above pH 6.5, corresponding to the change in the major Nb species from the neutral Nb(OH){sub 5} to the low-sorbing anionic Nb(OH){sub 6}{sup -} and Nb(OH){sub 7}{sup 2-}. However, the K{sub d} values in the model soil solution were in the slightly alkaline range an order of magnitude higher than in pure water, which is probably caused by the formation of calcium niobate surface precipitate or electrostatic interaction between surface-sorbed calcium and solute Nb. Among nine soil constituent minerals kaolinite performed best in retaining Nb in both pure water and model soil solution at pH 8, whereas potassium feldspar showed the poorest sorption. The K{sub d} value for kaolinite was above 500000 mL/g in both solutions, while the respective potassium feldspar values were in the range of 120-220 mL/g.

  16. Study on a 5.0 W/80 K single stage Stirling type pulse tube cryocooler

    Institute of Scientific and Technical Information of China (English)

    Zhi-hua GAN; Guo-jun LIU; Ying-zhe WU; Qiang CAO; Li-min QIU; Guo-bang CHEN; J.M.PFOTENHAUER

    2008-01-01

    A single stage Stifling pulse tube cryocooler was designed based on REGEN 3.2 and fabricated for testing.The experimental results show that the cooler can provide a cooling capacity of 5.0 W at 79.1 K,and produce a no-load temperature of 57.0 K,operating with an average pressure of 2.50 Mpa and a frequency of 60 Hz,performance results that are very close to the calculated values.The cryoeooler can be cooled from room temperature to 80 K in 8.5 min.The fast cooldown time is a result of the small regenerator.

  17. Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas

    Energy Technology Data Exchange (ETDEWEB)

    Chu, X. X.; Zhang, D. X.; Qian, Y.; Liu, W. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800 (China); Zhang, M. M.; Xu, D. [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 (China)

    2014-01-29

    In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H{sub 2} from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H{sub 2} in helium recycle gas are less than 1 ppb.

  18. Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas

    Science.gov (United States)

    Chu, X. X.; Zhang, M. M.; Zhang, D. X.; Xu, D.; Qian, Y.; Liu, W.

    2014-01-01

    In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H2 from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H2 in helium recycle gas are less than 1 ppb.

  19. Performance Study on ST/JT Hybrid Cryocoolers Working at Liquid Helium Temperature

    Science.gov (United States)

    Dongli, Liu; Xuan, Tao; Xiao, Sun; Zhihua, Gan

    The ST/JT hybridcryocooler consists of a Stirling-typecryocooler and a J-T loop. The common process of steady-state operation is given. Pressure-Enthalpy map analysis and thermodynamic calculation showhow the precooling temperature, high pressure and recuperator effectiveness affect thecooling powerat liquid helium temperature. Applying the current performance level of the Stirling cooler,the overall COP of the hybrid cryocooleris roughly optimized. This performance study shows that the hybrid cryocooler can develop its performance potential with improved J-T compressors with larger pressure ratio and aprecooler working at lower temperature.

  20. Precooling of a superconducting magnet using a cryocooler and thermal switches.

    Science.gov (United States)

    Yamamoto, J; Yanai, M

    1979-11-01

    A simple precooling system for a superconducting magnet is developed using a Cryomech GB02 cryocooler and gas filled thermal switches. A superconducting magnet (NbTi wire, 7 T of maximum field, 5.6 kg of weight) is precooled to 16 K in about 70 h without any manual control. Heat transfer rate of each thermal switch (H2 or N2 gas filled at 1.3 MPa at room temperature) is about 3x10(-1) W/K during the ON state, and 5x10(-3) W/K during the OFF state.