Sample records for residential unitary low-temperature

  1. Simulation and optimization study on a solar space heating system combined with a low temperature ASHP for single family rural residential houses in Beijing

    DEFF Research Database (Denmark)

    Deng, Jie; Tian, Zhiyong; Fan, Jianhua


    A pilot project of the solar water heating system combined with a low temperature air source heat pump (ASHP) unit was established in 2014 in a detached residential house in the rural region of Beijing, in order to investigate the system application prospect for single family houses via system op...... the integrated solar space heating for reducing carbon emission, it is suggested that the Beijing municipal government should offer some financial subsidy to compensate the equivalent solar heat price per kWh....... pilot household on the current electricity price level of 0.5 RMB/kWh, comparing with the reference condition of the fully ASHP space heating. It is further found that the equivalent solar heat price per kWh is too high under the current solar market cost price and collector technology. To put forward...

  2. WORKSHOP: Low temperature devices

    International Nuclear Information System (INIS)



    With extraterrestrial neutrinos (whether from the sun or further afield) continuing to make science news, and with the search for the so far invisible 'dark matter' of the universe a continual preoccupation, physicists from different walks of life (solid state, low temperature, particles, astrophysics) gathered at a workshop on low temperature devices for the detection of neutrinos and dark matter, held from 12-13 March at Ringberg Castle on Lake Tegernsee in the Bavarian Alps, and organized by the Max Planck Institute for Physics and Astrophysics in Munich

  3. Low temperatures - hot topic

    International Nuclear Information System (INIS)



    Neutrino mass measurements, next-generation double beta experiments, solar neutrino detection, searches for magnetic monopoles and the challenge of discovering what most of the Universe is made of (dark matter), not to mention axions (cosmic and solar), supersymmetric neutral particles and cosmic neutrinos. All this physics could use cryogenic techniques. Thus the second European Workshop on Low Temperature Devices for the Detection of Low Energy Neutrinos and Dark Matter, held at LAPP (Annecy) in May, covered an active and promising field

  4. Low-Temperature Physics

    CERN Document Server

    Enss, Christian


    This book provides a concise but thorough introduction to important phenomena of low-temperature physics. It is ideally suited as a textbook for advanced undergraduates but will also be valuable for graduate students, scientists and engineers working in this field. Clear explanations of both theoretical and experimental approaches coupled with carefully selected problems will enable students to gain a firm understanding of even the most recent research developments.

  5. Mutually unbiased unitary bases (United States)

    Shaari, Jesni Shamsul; Nasir, Rinie N. M.; Mancini, Stefano


    We consider the notion of unitary transformations forming bases for subspaces of M (d ,C ) such that the square of the Hilbert-Schmidt inner product of matrices from the differing bases is a constant. Moving from the qubit case, we construct the maximal number of such bases for the four- and two-dimensional subspaces while proving the nonexistence of such a construction for the three-dimensional case. Extending this to higher dimensions, we commit to such a construct for the case of qutrits and provide evidence for the existence of such unitaries for prime dimensional quantum systems. Focusing on the qubit case, we show that the average fidelity for estimating any such transformation is equal to the case for estimating a completely unknown unitary from SU(2 ) . This is then followed by a quick application for such unitaries in a quantum cryptographic setup.

  6. Low Temperature Plasma Medicine (United States)

    Graves, David


    Ionized gas plasmas near room temperature are used in a remarkable number of technological applications mainly because they are extraordinarily efficient at exploiting electrical power for useful chemical and material transformations near room temperature. In this tutorial address, I will focus on the newest area of low temperature ionized gas plasmas (LTP), in this case operating under atmospheric pressure conditions, in which the temperature-sensitive material is living tissue. LTP research directed towards biomedical applications such as sterilization, surgery, wound healing and anti-cancer therapy has seen remarkable growth in the last 3-5 years, but the mechanisms responsible for the biomedical effects have remained mysterious. It is known that LTP readily create reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS (or RONS), in addition to a suite of other radical and non-radical reactive species, are essential actors in an important sub-field of aerobic biology termed ``redox'' (or oxidation-reduction) biology. I will review the evidence suggesting that RONS generated by plasmas are responsible for their observed therapeutic effects. Other possible bio-active mechanisms include electric fields, charges and photons. It is common in LTP applications that synergies between different mechanisms can play a role and I will review the evidence for synergies in plasma biomedicine. Finally, I will address the challenges and opportunities for plasma physicists to enter this novel, multidisciplinary field.

  7. On random unitary channels

    International Nuclear Information System (INIS)

    Audenaert, Koenraad M R; Scheel, Stefan


    In this paper, we provide necessary and sufficient conditions for a completely positive trace-preserving (CPT) map to be decomposable into a convex combination of unitary maps. Additionally, we set out to define a proper distance measure between a given CPT map and the set of random unitary maps, and methods for calculating it. In this way one could determine whether non-classical error mechanisms such as spontaneous decay or photon loss dominate over classical uncertainties, for example, in a phase parameter. The present paper is a step towards achieving this goal

  8. Unitary management, multiple practices? (United States)

    Johansen, Monica Skjøld; Gjerberg, Elisabeth


    The purpose of this paper is to explore whether unitary managers with different professional backgrounds carry out and reflect differently upon their roles as unitary managers. This paper presents findings from two different studies, comprising both data from qualitative interviews and a nationwide survey. Doctors and nurses in many respects perform their roles as unitary managers differently. They hold the same position but carry out their roles differently. Doctors are very committed to clinical tasks and stress to a great extent that clinical tasks should be integrated in management at the department level. The opposite is true for the nurses, where leadership first and foremost should be understood as management. Even though doctors and nurses are in the same position they manage differently, being committed to different tasks within the unit. This is not the intention of the reform. However, the question is thus, will this have (severe) consequences for the organization? Or does it represent a healthy diversity in the health organisation? This paper explores whether different professions carry out their managerial tasks differently and what practical implications this could have. It brings to the fore substantial empirical data on how one of the major reforms in Norwegian (and international) health care has been adopted and carried out by major professional groups.

  9. Low-temperature tracking detectors

    CERN Document Server

    Niinikoski, T O; Anbinderis, P; Anbinderis, T; D'Ambrosio, N; de Boer, Wim; Borchi, E; Borer, K; Bruzzi, M; Buontempo, S; Chen, W; Cindro, V; Dezillie, B; Dierlamm, A; Eremin, V; Gaubas, E; Gorbatenko, V; Granata, V; Grigoriev, E; Grohmann, S; Hauler, F; Heijne, Erik H M; Heising, S; Hempel, O; Herzog, R; Härkönen, J; Ilyashenko, Yu S; Janos, S; Jungermann, L; Kalesinskas, V; Kapturauskas, J; Laiho, R; Li, Z; Luukka, Panja; Mandic, I; De Masi, R; Menichelli, D; Mikuz, M; Militaru, O; Nüssle, G; O'Shea, V; Pagano, S; Paul, S; Perea-Solano, B; Piotrzkowski, K; Pirollo, S; Pretzl, K; Rahman, M; Rato-Mendes, P; Rouby, X; Ruggiero, G; Smith, K; Sousa, P; Tuominen, E; Tuovinen, E; Vaitkus, J; Verbitskaya, E; Da Vià, C; Vlasenko, L; Vlasenko, M; Wobst, E; Zavrtanik, M


    RD39 collaboration develops new detector techniques for particle trackers, which have to withstand fluences up to 10/sup 16/ cm/sup -2 / of high-energy particles. The work focuses on the optimization of silicon detectors and their readout electronics while keeping the temperature as a free parameter. Our results so far suggest that the best operating temperature is around 130 K. We shall also describe in this paper how the current-injected mode of operation reduces the polarization of the bulk silicon at low temperatures, and how the engineering and materials problems related with vacuum and low temperature can be solved. (9 refs).

  10. Low-temperature thermal expansion

    International Nuclear Information System (INIS)

    Collings, E.W.


    This chapter discusses the thermal expansion of insulators and metals. Harmonicity and anharmonicity in thermal expansion are examined. The electronic, magnetic, an other contributions to low temperature thermal expansion are analyzed. The thermodynamics of the Debye isotropic continuum, the lattice-dynamical approach, and the thermal expansion of metals are discussed. Relative linear expansion at low temperatures is reviewed and further calculations of the electronic thermal expansion coefficient are given. Thermal expansions are given for Cu, Al and Ti. Phenomenologic thermodynamic relationships are also discussed

  11. Certification testing at low temperatures

    International Nuclear Information System (INIS)

    Noss, P.W.; Ammerman, D.J.


    Regulations governing the transport of radioactive materials require that most hypothetical accident condition tests or analyses consider the effects of the environmental temperature that most challenges package performance. For many packages, the most challenging temperature environment is the cold condition (-29 C according to U.S. regulations), primarily because the low temperature causes the highest free drop impact forces due to the higher strength of many energy-absorbing materials at this temperature. If it is decided to perform low temperature testing, it is only necessary that the relevant parts of the package have the required temperature prior to the drop. However, the details of performing a drop at low temperature can have a large influence on testing cost and technical effectiveness. The selection of the test site, the chamber and type of chilling equipment, instrumentation, and even the time of year are all important. Control of seemingly minor details such as the effect on internal pressure, placement of monitoring thermocouples, the thermal time constant of the test article, and icing of equipment are necessary to ensure a successful low temperature test. This paper will discuss these issues and offer suggestions based on recent experience

  12. Low temperature fuel behavior studies (United States)

    Stockemer, F. J.


    Aircraft fuels at low temperatures near the freezing point. The principal objective was an improved understanding of the flowability and pumpability of the fuels in a facility that simulated the heat transfer and temperature profiles encountered during flight in the long range commercial wing tanks.

  13. Catalysts for low temperature oxidation (United States)

    Toops, Todd J.; Parks, III, James E.; Bauer, John C.


    The invention provides a composite catalyst containing a first component and a second component. The first component contains nanosized gold particles. The second component contains nanosized platinum group metals. The composite catalyst is useful for catalyzing the oxidation of carbon monoxide, hydrocarbons, oxides of nitrogen, and other pollutants at low temperatures.

  14. Automatic low-temperature calorimeter

    International Nuclear Information System (INIS)

    Malyshev, V.M.; Mil'ner, G.A.; Shibakin, V.F.; Sorkin, E.L.


    This paper describes a low-temperature adiabatic calorimeter with a range of 1.5-500K. The system for maintaining adiabatic conditions is implemented by two resitance thermometers, whose sensitivity at low temperatures is several orders higher than that of thermocouples. The calorimeter cryostat is installed in an STG-40 portable Dewar flask. The calorimeter is controlled by an Elektronika-60 microcomputer. Standard platinum and germanium thermometers were placed inside of the calorimeter to calibrate the thermometers of the calorimeter and the shield, and the specific heats of specimens of OSCh 11-4 copper and KTP-8 paste were measured to demonstrate the possibilities of the described calorimeter. Experience with the calorimeter has shown that a thorough study of the dependence of heat capacity on temperature (over 100 points for one specimen) can be performed in one or two dats

  15. Sustained Low Temperature NOx Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Zha, Yuhui


    Increasing regulatory, environmental, and customer pressure in recent years led to substantial improvements in the fuel efficiency of diesel engines, including the remarkable breakthroughs demonstrated through the Super Truck program supported by the U.S. Department of Energy (DOE). On the other hand, these improvements have translated into a reduction of exhaust gas temperatures, thus further complicating the task of controlling NOx emissions, especially in low power duty cycles. The need for improved NOx conversion over these low temperature duty cycles is also observed as requirements tighten with in-use emissions testing. Sustained NOx reduction at low temperatures, especially in the 150-200oC range, shares some similarities with the more commonly discussed cold-start challenge, however poses a number of additional and distinct technical problems. In this project we set a bold target of achieving and maintaining a 90% NOx conversion at the SCR catalyst inlet temperature of 150oC. The project is intended to push the boundaries of the existing technologies, while staying within the realm of realistic future practical implementation. In order to meet the resulting challenges at the levels of catalyst fundamentals, system components, and system integration, Cummins has partnered with the DOE, Johnson Matthey, and Pacific Northwest National Lab and initiated the Sustained Low-Temperature NOx Reduction program at the beginning of 2015. Through this collaboration, we are exploring catalyst formulations and catalyst architectures with enhanced catalytic activity at 150°C; opportunities to approach the desirable ratio of NO and NO2 in the SCR feed gas; options for robust low-temperature reductant delivery; and the requirements for overall system integration. The program is expected to deliver an on-engine demonstration of the technical solution and an assessment of its commercial potential. In the SAE meeting, we will share the initial performance data on engine to

  16. Energy and exergy analysis of low temperature district heating network

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend


    is designed to supply heating for 30 low energy detached residential houses. The network operational supply/return temperature is set as 55 °C/25 °C, which is in line with a pilot project carried out in Denmark. Two types of in-house substations are analyzed to supply the consumer domestic hot water demand......Low temperature district heating with reduced network supply and return temperature provides better match of the low quality building heating demand and the low quality heating supply from waste heat or renewable energy. In this paper, a hypothetical low temperature district heating network....... The space heating demand is supplied through floor heating in the bathroom and low temperature radiators in the rest of rooms. The network thermal and hydraulic conditions are simulated under steady state. A district heating network design and simulation code is developed to incorporate the network...

  17. Mechanical pumping at low temperature

    International Nuclear Information System (INIS)

    Perin, J.P.; Claudet, G.; Disdier, F.


    This novel concept consist of a mechanical pump able to run at low temperature (25K). Since gas density varies inversely with temperature, this pump would deliver much higher mass flow rate than at room temperature for a given size. Advantages of this concept are order of magnitude reduction in size, weight, when compared to a conventional pump scaled to perform the same mass flow rate at room temperature. This pump would be a solution to allow continuously tritium extraction and minimize the mass inventory. (orig.)

  18. Ammonia synthesis at low temperatures

    DEFF Research Database (Denmark)

    Rod, Thomas Holm; Logadottir, Ashildur; Nørskov, Jens Kehlet


    Density functional theory (DFT) calculations of reaction paths and energies for the industrial and the biological catalytic ammonia synthesis processes are compared. The industrial catalyst is modeled by a ruthenium surface, while the active part of the enzyme is modeled by a MoFe6S9 complex...... have been carried out to evaluate its feasibility. The calculations suggest that it might be possible to catalytically produce ammonia from molecular nitrogen at low temperatures and pressures, in particular if energy is fed into the process electrochemically. (C) 2000 American Institute of Physics....

  19. Thermoluminescent system for low temperatures

    International Nuclear Information System (INIS)

    Rosa, L.A.R. da; Caldas, L.V.E.; Leite, N.G.


    A system for measurements of the thermoluminescent glow curve, the thermoluminescent emission spectrum and the optical absorption spectrum of solid samples, from liquid nitrogen temperature up to 473 K, is reported. A specially designed temperature programmer provides a linear heating of the sample at a wide range of selectable heating rates, as also long term steady-state temperatures for annealing and isothermal decay studies. The system operates at a pressure of 1.33 x 10 -3 Pa. Presently it is being used for lithium fluoride low temperature thermoluminescent studies. (author) [pt

  20. The Low Temperature CFB Gasifier

    DEFF Research Database (Denmark)

    Stoholm, P.; Nielsen, Rasmus Glar; Richardt, K.


    The Low Temperature Circulating Fluidised Bed (LT-CFB) gasification process is described together with the 50 kW and the 500 kW test plants and latest test results. The LT-CFB process is especially developed for medium and large scale (few to >100 MW) gasification of problematic bio-fuels like...... of experiments with the 50 kW test plant with two extremely difficult types of straw has shown low char losses and high retentions of ash including e.g. potassium. Latest 27 hours of experiments with dried, high ash pig- and hen manure has further indicated the concepts high fuel flexibility. The new 500 kW test...

  1. The Low temperature CFB gasifier

    DEFF Research Database (Denmark)

    Stoholm, P.; Nielsen, Rasmus Glar; Fock, Martin W.


    The Low Temperature Circulating Fluidised Bed (LT-CFB) gasification process aims at avoiding problems due to ash deposition and agglomeration when using difficult fuels such as agricultural biomass and many waste materials. This, as well as very simple gas cleaning, is achieved by pyrolysing...... the fuel at around 650?C in a CFB reaction chamber and subsequently gasifying the char at around 730oC in a slowly fluidised bubbling bed chamber located in the CFB particle recirculation path. In this paper the novel LT-CFB concept is further described together with the latest test results from the 50 k......W LT-CFB test plant located at the Technical University of Denmark. In the latest 10-hour experiment the fuel was wheat straw containing 1,3-1,6% potassium, 0,6% chlorine and 12,2% ash (dry basis), and the bed material was ordinary silica sand without additives. The bed material was reused from 45...

  2. Low Temperature Hydrogen Antihydrogen Interactions

    International Nuclear Information System (INIS)

    Armour, E. A. G.; Chamberlain, C. W.


    In view of current interest in the trapping of antihydrogen (H-bar) atoms at low temperatures, we have carried out a full four-body variational calculation to determine s-wave elastic phase shifts for hydrogen antihydrogen scattering, using the Kohn Variational Principle. Terms outside the Born-Oppenheimer approximation have been taken into account using the formalism of Kolos and Wolniewicz. As far as we are aware, this is the first time that these terms have been included in an H H-bar scattering calculation. This is a continuation of earlier work on H-H-bar interactions. Preliminary results differ substantially from those calculated using the Born-Oppenheimer approximation. A method is outlined for reducing this discrepancy and taking the rearrangement channel into account.


    Energy Technology Data Exchange (ETDEWEB)

    Harlan U. Anderson


    This project has three main goals: Thin Films Studies, Preparation of Graded Porous Substrates and Basic Electrical Characterization and Testing of Planar Single Cells. During this time period substantial progress has been made in developing low temperature deposition techniques to produce dense, nanocrystalline yttrium-stabilized zirconia films on both dense oxide and polymer substrates. Progress has been made in the preparation and characterization of thin electrolytes and porous LSM substrates. Both of these tasks are essentially on or ahead of schedule. In our proposal, we suggested that the ZrO{sub 2}/Sc system needed to be considered as a candidate as a thin electrolyte. This was because microcrystalline ZrO{sub 2}/Sc has a significantly higher ionic conductivity than YSZ, particularly at the lower temperatures. As a result, some 0.5 micron thick film of ZrO{sub 2}/16% Sc on an alumina substrate (grain size 20nm) was prepared and the electrical conductivity measured as a function of temperature and oxygen activity. The Sc doped ZrO{sub 2} certainly has a higher conductivity that either 20nm or 2400nm YSZ, however, electronic conductivity dominates the conductivity for oxygen activities below 10{sup -15}. Whereas for YSZ, electronic conductivity is not a problem until the oxygen activity decreases below 10{sup -25}. These initial results show that the ionic conductivity of 20nm YSZ and 20nm ZrO{sub 2}/16% Sc are essentially the same and the enhanced conductivity which is observed for Sc doping in microcrystalline specimens is not observed for the same composition when it is nanocrystalline. In addition they show that the electronic conductivity of Sc doped ZrO{sub 2} is at least two orders of magnitude higher than that observed for YSZ. The conclusion one reaches is that for 0.5 to 1 micron thick nanocrystalline films, Sc doping of ZrO{sub 2} has no benefits compared to YSZ. As a result, electrolyte films of ZrO{sub 2}/Sc should not be considered as candidates

  4. Exergy and Energy Analysis of Low Temperature District Heating Network

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    Low temperature district heating (LTDH) with reduced network supply and return temperature provides better match of the low quality building thermal demand and the low quality waste heat supply. In this paper, an exemplary LTDH network was designed for 30 low energy demand residential houses, which...... is in line with a pilot project that is carrying out in Denmark with network supply/return temperature at 55oC/25 oC. The consumer domestic hot water (DHW) demand is supplied with a special designed district heating (DH) storage tank. The space heating (SH) demand is supplied with a low temperature radiator....... The network thermal and hydraulic conditions were simulated under steady state with an in-house district heating network design and simulation code. Through simulation, the overall system energetic and exergetic efficiencies were calculated and the exergy losses for the major district heating system...

  5. Matter and Methods at Low Temperatures

    CERN Document Server

    Pobell, F


    Matter and Methods at Low Temperatures contains a wealth of information essential for successful experiments at low temperatures, which makes it suitable as a reference and textbook. The first chapters describe the low-temperature properties of liquid and solid matter, including liquid helium. The major part of the book is devoted to refrigeration techniques and the physics on which they rely, the definition of temperature, thermometry, and a variety of design and construction techniques. The lively style and practical basis of this text make it easy to read and particularly useful to anyone beginning research in low-temperature physics. Low-temperature scientists will find it of great value due to its extensive compilation of materials data and relevant new results on refrigeration, thermometry, and materials properties. Problems are included as well. Furthermore, this third edition also describes newly developed low-temperature experimentation techniques and new materials properties; it also contains many a...

  6. Estimation of unitary quantum operations

    International Nuclear Information System (INIS)

    Ballester, Manuel A.


    The problem of optimally estimating an unknown unitary quantum operation with the aid of entanglement is addressed. The idea is to prepare an entangled pair, apply the unknown unitary to one of the two parts, and then measure the joint output state. This measurement could be an entangled one or it could be separable (e.g., measurements which can be implemented with local operations and classical communication or LOCC). A comparison is made between these possibilities and it is shown that by using nonseparable measurements one can improve the accuracy of the estimation by a factor of 2(d+1)/d where d is the dimension of the Hilbert space on which U acts

  7. Unitary equivalence of quantum walks

    International Nuclear Information System (INIS)

    Goyal, Sandeep K.; Konrad, Thomas; Diósi, Lajos


    Highlights: • We have found unitary equivalent classes in coined quantum walks. • A single parameter family of coin operators is sufficient to realize all simple one-dimensional quantum walks. • Electric quantum walks are unitarily equivalent to time dependent quantum walks. - Abstract: A simple coined quantum walk in one dimension can be characterized by a SU(2) operator with three parameters which represents the coin toss. However, different such coin toss operators lead to equivalent dynamics of the quantum walker. In this manuscript we present the unitary equivalence classes of quantum walks and show that all the nonequivalent quantum walks can be distinguished by a single parameter. Moreover, we argue that the electric quantum walks are equivalent to quantum walks with time dependent coin toss operator

  8. Unitary Housing Regimes in Transition

    DEFF Research Database (Denmark)

    Bengtsson, Bo; Jensen, Lotte


    Path dependence is strong in housing institutions and policy. In both Denmark and Sweden, today’s universal and ‘unitary’ (Kemeny) housing regimes can be traced back to institutions that were introduced fifty years back in history or more. Recently, universal and unitary housing systems...... in Scandinavia, and elsewhere, are under challenge from strong political and economic forces. These challenges can be summarized as economic cutbacks, privatization and Europeanization. Although both the Danish and the Swedish housing system are universal and unitary in character, they differ considerably...... in institutional detail. Both systems have corporatist features, however in Denmark public housing is based on local tenant democracy and control, and in Sweden on companies owned and controlled by the municipalities, combined with a centralized system of rent negotiations. In the paper the present challenges...

  9. Unitary deformations of counterdiabatic driving (United States)

    Takahashi, Kazutaka


    We study a deformation of the counterdiabatic-driving Hamiltonian as a systematic strategy for an adiabatic control of quantum states. Using a unitary transformation, we design a convenient form of the driver Hamiltonian. We apply the method to a particle in a confining potential and discrete systems to find explicit forms of the Hamiltonian and discuss the general properties. The method is derived by using the quantum brachistochrone equation, which shows the existence of a nontrivial dynamical invariant in the deformed system.

  10. Low temperature study of nonstoichiometric titanium carbide

    International Nuclear Information System (INIS)

    Tashmetov, M.Yu.


    By low temperature neutron diffraction method was studied structure in nonstoichiometric titanium carbide from room temperature up to 12K. It is found of low temperature phase in titanium carbide- TiC 0.71 . It is established region and borders of this phase. It is determined change of unit cell parameter. (author)

  11. Extremely low temperature properties of epoxy GFRP

    International Nuclear Information System (INIS)

    Kadotani, Kenzo; Nagai, Matao; Aki, Fumitake.


    The examination of fiber-reinforced plastics, that is, plastics such as epoxy, polyester and polyimide reinforced with high strength fibers such as glass, carbon, boron and steel, for extremely low temperature use began from the fuel tanks of rockets. Therafter, the trial manufacture of superconducting generators and extremely low temperature transformers and the manufacture of superconducting magnets for nuclear fusion experimental setups became active, and high performance FRPs have been adopted, of which the extremely low temperature properties have been sufficiently grasped. Recently, the cryostats made of FRPs have been developed, fully utilizing such features of FRPs as high strength, high rigidity, non-magnetic material, insulation, low heat conductivity, light weight and the freedom of molding. In this paper, the mechanical properties at extremely low temperature of the plastic composite materials used as insulators and structural materials for extremely low temperature superconducting equipment is outlined, and in particular, glass fiber-reinforced epoxy laminates are described somewhat in detail. The fracture strain of GFRP at extremely low temperature is about 1.3 times as large as that at room temperature, but at extremely low temperature, clear cracking occurred at 40% of the fracture strain. The linear thermal contraction of GFRP showed remarkable anisotropy. (Kako, I.)

  12. Energy and exergy analysis of low temperature district heating network

    International Nuclear Information System (INIS)

    Li, Hongwei; Svendsen, Svend


    Low temperature district heating with reduced network supply and return temperature provides better match of the low quality building heating demand and the low quality heating supply from waste heat or renewable energy. In this paper, a hypothetical low temperature district heating network is designed to supply heating for 30 low energy detached residential houses. The network operational supply/return temperature is set as 55 °C/25 °C, which is in line with a pilot project carried out in Denmark. Two types of in-house substations are analyzed to supply the consumer domestic hot water demand. The space heating demand is supplied through floor heating in the bathroom and low temperature radiators in the rest of rooms. The network thermal and hydraulic conditions are simulated under steady state. A district heating network design and simulation code is developed to incorporate the network optimization procedure and the network simultaneous factor. Through the simulation, the overall system energy and exergy efficiencies are calculated and the exergy losses for the major district heating system components are identified. Based on the results, suggestions are given to further reduce the system energy/exergy losses and increase the quality match between the consumer heating demand and the district heating supply. -- Highlights: ► Exergy and energy analysis for low and medium temperature district heating systems. ► Different district heating network dimensioning methods are analyzed. ► Major exergy losses are identified in the district heating network and the in-house substations. ► Advantages to apply low temperature district heating are highlighted through exergy analysis. ► The influence of thermal by-pass on system exergy/energy performance is analyzed.

  13. Improved Low Temperature Performance of Supercapacitors (United States)

    Brandon, Erik J.; West, William C.; Smart, Marshall C.; Gnanaraj, Joe


    Low temperature double-layer capacitor operation enabled by: - Base acetonitrile / TEATFB salt formulation - Addition of low melting point formates, esters and cyclic ethers center dot Key electrolyte design factors: - Volume of co-solvent - Concentration of salt center dot Capacity increased through higher capacity electrodes: - Zeolite templated carbons - Asymmetric cell designs center dot Continuing efforts - Improve asymmetric cell performance at low temperature - Cycle life testing Motivation center dot Benchmark performance of commercial cells center dot Approaches for designing low temperature systems - Symmetric cells (activated carbon electrodes) - Symmetric cells (zeolite templated carbon electrodes) - Asymmetric cells (lithium titanate/activated carbon electrodes) center dot Experimental results center dot Summary

  14. [Low temperature plasma technology for biomass refinery]. (United States)

    Fu, Xiaoguo; Chen, Hongzhang


    Biorefinery that utilizes renewable biomass for production of fuels, chemicals and bio-materials has become more and more important in chemical industry. Recently, steam explosion technology, acid and alkali treatment are the main biorefinery treatment technologies. Meanwhile, low temperature plasma technology has attracted extensive attention in biomass refining process due to its unique chemical activity and high energy. We systemically summarize the research progress of low temperature plasma technology for pretreatment, sugar platflow, selective modification, liquefaction and gasification in biomass refinery. Moreover, the mechanism of low temperature plasma in biorefinery and its further development were also discussed.

  15. Low temperature sealing capabilities of fluoroelastomers

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, D.D.; Thomas, E.W.; Brown, J.H.; Revolta, W.N.K.


    The purpose of this article is to examine some traditional rubber methods of measuring low temperature properties and compare those results to a test designed to evaluate the low temperature static sealing of o-rings. Testing is performed on a variety of fluoroelastomers to document differences and establish trends. By evaluating the performance of various fluoroelastomers in a practical low temperature o-ring test, the design engineer may gain a better understanding of the low temperature sealing capabilities of these polymers. Although the test results disclosed in this article are of short duration, it is the intention of the authors to evaluate the effects of longer term compressive deformation, stress relaxation and hot/cold cycling with the static o-ring test device in future work.

  16. Low temperature plasma technology methods and applications

    CERN Document Server

    Chu, Paul K


    Written by a team of pioneering scientists from around the world, Low Temperature Plasma Technology: Methods and Applications brings together recent technological advances and research in the rapidly growing field of low temperature plasmas. The book provides a comprehensive overview of related phenomena such as plasma bullets, plasma penetration into biofilms, discharge-mode transition of atmospheric pressure plasmas, and self-organization of microdischarges. It describes relevant technology and diagnostics, including nanosecond pulsed discharge, cavity ringdown spectroscopy, and laser-induce

  17. Unitary Root Music and Unitary Music with Real-Valued Rank Revealing Triangular Factorization (United States)



  18. On Investigating GMRES Convergence using Unitary Matrices

    Czech Academy of Sciences Publication Activity Database

    Duintjer Tebbens, Jurjen; Meurant, G.; Sadok, H.; Strakoš, Z.


    Roč. 450, 1 June (2014), s. 83-107 ISSN 0024-3795 Grant - others:GA AV ČR(CZ) M100301201; GA MŠk(CZ) LL1202 Institutional support: RVO:67985807 Keywords : GMRES convergence * unitary matrices * unitary spectra * normal matrices * Krylov residual subspace * Schur parameters Subject RIV: BA - General Mathematics Impact factor: 0.939, year: 2014

  19. Transition from Poisson to circular unitary ensemble

    Indian Academy of Sciences (India)

    ensemble (SE). These are defined by invariance of the ensemble measure under the orthogonal, unitary and symplectic transformations respectively and are related to the time reversal and rotational symmetries of the system. Gaussian ensembles. (GE) of Hermitian matrices and circular ensembles (CE) of unitary matrices ...

  20. Unitary symmetry, combinatorics, and special functions

    Energy Technology Data Exchange (ETDEWEB)

    Louck, J.D.


    From 1967 to 1994, Larry Biedenham and I collaborated on 35 papers on various aspects of the general unitary group, especially its unitary irreducible representations and Wigner-Clebsch-Gordan coefficients. In our studies to unveil comprehensible structures in this subject, we discovered several nice results in special functions and combinatorics. The more important of these will be presented and their present status reviewed.

  1. Unitary scintillation detector and system (United States)

    McElhaney, S.A.; Chiles, M.M.


    The invention is a unitary alpha, beta, and gamma scintillation detector and system for sensing the presence of alpha, beta, and gamma radiations selectively or simultaneously. The scintillators are mounted in a light-tight housing provided with an entrance window for admitting alpha, beta, and gamma radiation and excluding ambient light from the housing. Light pulses from each scintillator have different decay constants that are converted by a photosensitive device into corresponding differently shaped electrical pulses. A pulse discrimination system identifies the electrical pulses by their respective pulse shapes which are determined by decay time. The identified electrical pulses are counted in separate channel analyzers to indicate the respective levels of sensed alpha, beta, and gamma radiations. 10 figs.

  2. A unitary correlation operator method

    Energy Technology Data Exchange (ETDEWEB)

    Feldmeier, H.; Neff, T.; Roth, R.; Schnack, J.


    The short range repulsion between nucleons is treated by a unitary correlation operator which shifts the nucleons away from each other whenever their uncorrelated positions are within the repulsive core. By formulating the correlation as a transformation of the relative distance between particle pairs, general analytic expressions for the correlated wave functions and correlated operators are given. The decomposition of correlated operators into irreducible n-body operators is discussed. The one- and two-body-irreducible parts are worked out explicitly and the contribution of three-body correlations is estimated to check convergence. Ground state energies of nuclei up to mass number A=48 are calculated with a spin-isospin-dependent potential and single Slater determinants as uncorrelated states. They show that the deduced energy- and mass-number-independent correlated two-body Hamiltonian reproduces all ``exact`` many-body calculations surprisingly well. (orig.)

  3. Thermo-economic optimization of secondary distribution network of low temperature district heating network under local conditions of South Korea

    DEFF Research Database (Denmark)

    Park, Byung Sik; Imran, Muhammad; Hoon, Im-Yong


    A secondary distribution network of a low temperature district heating system is designed and optimized for a residential apartment complex under the local conditions of South Korea in the TRNSYS simulation environment. The residential apartment complex is a typical example of Korean residential...... °C, area of heat exchanger is increased by 68.2%, pumping power is also increased by 9.8% and heat loss is reduced by 15.6%. These results correspond to a temperature difference of 20 °C, the standard temperature difference in South Korea residential heating system. Economic assessment...

  4. Basics of Low-temperature Refrigeration

    CERN Document Server

    Alekseev, A.


    This chapter gives an overview of the principles of low temperature refrigeration and the thermodynamics behind it. Basic cryogenic processes - Joule-Thomoson process, Brayton process as well as Claude process - are described and compared. A typical helium laboratory refrigerator based on Claude process is used as a typical example of a low-temperature refrigeration system. A description of the hardware components for helium liquefaction is an important part of this paper, because the design of the main hardware components (compressors, turbines, heat exchangers, pumps, adsorbers, etc.) provides the input for cost calculation, as well as enables to estimate the reliability of the plant and the maintenance expenses. All these numbers are necessary to calculate the economics of a low temperature application.

  5. Kinetics and spectroscopy of low temperature plasmas

    CERN Document Server

    Loureiro, Jorge


    This is a comprehensive textbook designed for graduate and advanced undergraduate students. Both authors rely on more than 20 years of teaching experience in renowned Physics Engineering courses to write this book addressing the students’ needs. Kinetics and Spectroscopy of Low Temperature Plasmas derives in a full self-consistent way the electron kinetic theory used to describe low temperature plasmas created in the laboratory with an electrical discharge, and presents the main optical spectroscopic diagnostics used to characterize such plasmas. The chapters with the theoretical contents make use of a deductive approach in which the electron kinetic theory applied to plasmas with basis on the electron Boltzmann equation is derived from the basic concepts of Statistical and Plasma Physics. On the other hand, the main optical spectroscopy diagnostics used to characterize experimentally such plasmas are presented and justified from the point of view of the Atomic and Molecular Physics. Low temperature plasmas...

  6. Tar removal from low-temperature gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Zwart, R.W.R. [ECN Biomass, Petten (Netherlands); Van der Heijden, Simon; Emmen, R. [Dahlman, Maassluis (Netherlands); Dall Bentzen, Jens [Dall Energy, Hoersholm (Denmark); Ahrenfeldt, Jesper [Risoe DTU, Roskilde (Denmark); Stoholm, Peder [DFBT, Roskilde (Denmark); Krogh, Jorn [Anhydro, Soeborg (Denmark)


    In the title project two gas cleaning technologies are adapted and tested in connection to low-temperature gasification. These concern the OLGA tar removal technology developed by the Dutch partners in the project and the cooling, filtration and partial oxidation developed by the Danish partners in the project. This project aimed at judging the technical and economical suitability of two up-scalable tar removal methods (OLGA and Partial Oxidation) connected to high-efficiency low-temperature gasification. Suitability opens the way to high efficient and high fuel flexible biomass gasification systems for the connection to gas engines, gas turbines, fuel cells or catalytic synthesis gas reactors.

  7. Materials for low-temperature fuel cells

    CERN Document Server

    Ladewig, Bradley; Yan, Yushan; Lu, Max


    There are a large number of books available on fuel cells; however, the majority are on specific types of fuel cells such as solid oxide fuel cells, proton exchange membrane fuel cells, or on specific technical aspects of fuel cells, e.g., the system or stack engineering. Thus, there is a need for a book focused on materials requirements in fuel cells. Key Materials in Low-Temperature Fuel Cells is a concise source of the most important and key materials and catalysts in low-temperature fuel cells. A related book will cover key materials in high-temperature fuel cells. The two books form part

  8. Neutrinos, dark matter and low temperature detectors

    International Nuclear Information System (INIS)

    Gonzalez-Mestres, L.; Perret-Gallix, D.


    The present status of cryogenic detector developments for particle physics is discussed, with emphasis on applications at the cross-disciplinary frontier between particle physics and astrophysics, where low temperature devices appear to be particularly well suited. The overwiew of results is completed by a sketch of new ideas and possible ways for further improvements. Neutrino role importance is particularly shown

  9. Industrial Applications of Low Temperature Plasmas

    International Nuclear Information System (INIS)

    Bardsley, J N


    The use of low temperature plasmas in industry is illustrated by the discussion of four applications, to lighting, displays, semiconductor manufacturing and pollution control. The type of plasma required for each application is described and typical materials are identified. The need to understand radical formation, ionization and metastable excitation within the discharge and the importance of surface reactions are stressed

  10. Mechanism of bacterial adaptation to low temperature

    Indian Academy of Sciences (India)

    Survival of bacteria at low temperatures provokes scientific interest because of several reasons. Investigations in this area promise insight into one of the mysteries of life science – namely, how the machinery of life operates at extreme environments. Knowledge obtained from these studies is likely to be useful in controlling ...

  11. Wood preservation of low-temperature carbonisation

    NARCIS (Netherlands)

    Gosselink, R.J.A.; Krosse, A.M.A.; Putten, van der J.C.; Kolk, van der J.C.; Klerk-Engels, de B.; Dam, van J.E.G.


    Pine (Pinus sylvestris L.) wood with dimensions (100 x 10 x 10mm) was thermally treated at 275degreesC in a muffle oven to impart resistance to microbial degradation. Low-temperature carbonised pine resulted in a visually homogeneously treated product with a substantial (about 70% w/w) reduced

  12. Fuzzy Logic Controller for Low Temperature Application (United States)

    Hahn, Inseob; Gonzalez, A.; Barmatz, M.


    The most common temperature controller used in low temperature experiments is the proportional-integral-derivative (PID) controller due to its simplicity and robustness. However, the performance of temperature regulation using the PID controller depends on initial parameter setup, which often requires operator's expert knowledge on the system. In this paper, we present a computer-assisted temperature controller based on the well known.

  13. New unitary affine-Virasoro constructions

    International Nuclear Information System (INIS)

    Halpern, M.B.; Kiritsis, E.; Obers, N.A.; Poratti, M.; Yamron, J.P.


    This paper reports on a quasi-systematic investigation of the Virasoro master equation. The space of all affine-Virasoro constructions is organized by K-conjugation into affine-Virasoro nests, and an estimate of the dimension of the space shows that most solutions await discovery. With consistent ansatze for the master equation, large classes of new unitary nests are constructed, including quadratic deformation nests with continuous conformal weights, and unitary irrational central charge nests, which may dominate unitary rational central charge on compact g

  14. Non-unitary probabilistic quantum computing (United States)

    Gingrich, Robert M.; Williams, Colin P.


    We present a method for designing quantum circuits that perform non-unitary quantum computations on n-qubit states probabilistically, and give analytic expressions for the success probability and fidelity.

  15. Quantum unitary dynamics in cosmological spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Cortez, Jerónimo, E-mail: [Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, México D.F. 04510 (Mexico); Mena Marugán, Guillermo A., E-mail: [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, 28006 Madrid (Spain); Velhinho, José M., E-mail: [Departamento de Física, Faculdade de Ciências, Universidade da Beira Interior, R. Marquês D’Ávila e Bolama, 6201-001 Covilhã (Portugal)


    We address the question of unitary implementation of the dynamics for scalar fields in cosmological scenarios. Together with invariance under spatial isometries, the requirement of a unitary evolution singles out a rescaling of the scalar field and a unitary equivalence class of Fock representations for the associated canonical commutation relations. Moreover, this criterion provides as well a privileged quantization for the unscaled field, even though the associated dynamics is not unitarily implementable in that case. We discuss the relation between the initial data that determine the Fock representations in the rescaled and unscaled descriptions, and clarify that the S-matrix is well defined in both cases. In our discussion, we also comment on a recently proposed generalized notion of unitary implementation of the dynamics, making clear the difference with the standard unitarity criterion and showing that the two approaches are not equivalent.

  16. The unitary space of particle internal states

    International Nuclear Information System (INIS)

    Perjes, Z.


    A relativistic theory of particle internal properties has been developed. Suppressing space-time information, internal wave functions and -observables are constructed in a 3-complex-dimensional space. The quantum numbers of a spinning point particle in this unitary space correspond with those of a low-mass hadron. Unitary space physics is linked with space-time notions via the Penrose theory of twistors, where new flavors may be represented by many-twistor systems. It is shown here that a four-twistor particle fits into the unitary space picture as a system of two points with equal masses and oppositely pointing unitary spins. Quantum states fall into the ISU(3) irreducible representations discovered by Sparling and the author. Full details of the computation involving SU(3) recoupling techniques are given. (author)

  17. Manufacturing Demonstration Facility: Low Temperature Materials Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graham, David E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Moon, Ji-Won [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Armstrong, Beth L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Datskos, Panos G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duty, Chad E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gresback, Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ivanov, Ilia N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jacobs, Christopher B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jellison, Gerald Earle [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jang, Gyoung Gug [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Joshi, Pooran C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jung, Hyunsung [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Meyer, III, Harry M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Phelps, Tommy [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    The Manufacturing Demonstration Facility (MDF) low temperature materials synthesis project was established to demonstrate a scalable and sustainable process to produce nanoparticles (NPs) for advanced manufacturing. Previous methods to chemically synthesize NPs typically required expensive, high-purity inorganic chemical reagents, organic solvents and high temperatures. These processes were typically applied at small laboratory scales at yields sufficient for NP characterization, but insufficient to support roll-to-roll processing efforts or device fabrication. The new NanoFermentation processes described here operated at a low temperature (~60 C) in low-cost, aqueous media using bacteria that produce extracellular NPs with controlled size and elemental stoichiometry. Up-scaling activities successfully demonstrated high NP yields and quality in a 900-L pilot-scale reactor, establishing this NanoFermentation process as a competitive biomanufacturing strategy to produce NPs for advanced manufacturing of power electronics, solid-state lighting and sensors.

  18. Building a Cryogen Efficient Low Temperature Lab (United States)

    Davis, John


    Over the past few years we have built a new low temperature laboratory at the University of Alberta to study quantum optomechanics and superfluids in confined geometries. With liquid helium at 11/liter in Alberta, helium consumption was a top concern, but so was vibration for optomechanics experiments and magnet stability for ultra-low temperature experiments. I will describe the wet system we have constructed, along with our automated helium recovery and delivery system. Currently our system runs, fully loaded with a sensitive optomechanics experiment at 9 mK, with a waste of one liquid liter equivalent per day of operation - with room for improvement. This may provide a model for both new laboratories and upgrades to existing wet systems.

  19. Approximate unitary equivalence of normaloid type operators


    Zhu, Sen


    In this paper, we explore approximate unitary equivalence of normaloid operators and classify several normaloid type operators including transaloid operators, polynomial-normaloid operators and von Neumann operators up to approximate unitary equivalence. As an application, we explore approximation of transaloid operators with closed numerical ranges. Among other things, it is proved that those transaloid operators with closed numerical ranges are norm dense in the class of transaloid operators.

  20. Low temperature behavior of nonequilibrium multilevel systems

    Czech Academy of Sciences Publication Activity Database

    Maes, C.; Netočný, Karel; O'Kelly de Galway, W.


    Roč. 47, č. 3 (2014), "035002-1"-"035002-11" ISSN 1751-8113 R&D Projects: GA ČR GAP204/12/0897 Institutional support: RVO:68378271 Keywords : nonequilibrium state state * low temperature Subject RIV: BE - Theoretical Physics Impact factor: 1.583, year: 2014

  1. Thermal expansion of glasses at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, K.G.


    The linear thermal expansion coefficient (..cap alpha.. = (par. deltalnL/par. deltaT)/sub p/) was measured at temperatures to 1.2K for two amorphous solids, fused silica and PMMA (polymethylmethacrylate, plexiglas), using a parallel plate capacitor differential dilatometer. The low temperature expansion coefficients for these solids have the same temperature dependences as the specific heats, and show a contribution which is linear in the temperature and which can be associated with the postulate of a broad distribution of two level states. The Grueneisen parameters which are associated with this contribution are comparable for the two solids (Y approx. = -16), and suggest a further indication of common behavior for amorphous solids at low temperature. Large magnitudes for Grueneisen parameters (/..gamma../ > 5) generally are associated with tunneling models. A symmetric double harmonic oscillator tunneling model can be used to understand the sign and magnitude of ..gamma.. for these solids. This model is inconsistent with other thermal and thermodynamic data for fused silica. The existence of similar negative and large magnitude Grueneisen parameters for these two amorphous solids places an additional constraint on theories for the low temperature properties of glasses.

  2. Minimizing material damage using low temperature irradiation (United States)

    Craven, E.; Hasanain, F.; Winters, M.


    Scientific advancements in healthcare driven both by technological breakthroughs and an aging and increasingly obese population have lead to a changing medical device market. Complex products and devices are being developed to meet the demands of leading edge medical procedures. Specialized materials in these medical devices, including pharmaceuticals and biologics as well as exotic polymers present a challenge for radiation sterilization as many of these components cannot withstand conventional irradiation methods. The irradiation of materials at dry ice temperatures has emerged as a technique that can be used to decrease the radiation sensitivity of materials. The purpose of this study is to examine the effect of low temperature irradiation on a variety of polymer materials, and over a range of temperatures from 0 °C down to -80 °C. The effectiveness of microbial kill is also investigated under each of these conditions. The results of the study show that the effect of low temperature irradiation is material dependent and can alter the balance between crosslinking and chain scission of the polymer. Low temperatures also increase the dose required to achieve an equivalent microbiological kill, therefore dose setting exercises must be performed under the environmental conditions of use.

  3. Honeycomb artificial spin ice at low temperatures (United States)

    Zeissler, Katharina; Chadha, Megha; Cohen, Lesley; Branford, Will


    Artificial spin ice is a macroscopic playground for magnetically frustrated systems. It consists of a geometrically ordered but magnetically frustrated arrangement of ferromagnetic macros spins, e.g. an arrangement of single domain ferromagnetic nanowires on a honeycomb lattice. Permalloy and cobalt which have critical temperature scales far above 290 K, are commonly used in the construction of such systems. Previous measurements have shown unusual features in the magnetotransport signature of cobalt honeycomb artificial spin ice at temperatures below 50 K which are due to changes in the artificial spin ice's magnetic reversal. In that case, the artificial spin ice bars were 1 micron long, 100 nm wide and 20 nm thick. Here we explore the low temperature magnetic behavior of honeycomb artificial spin ice structures with a variety of bar dimensions, indirectly via electrical transport, as well as, directly using low temperature magnetic imaging techniques. We discuss the extent to which this change in the magnetic reversal at low temperatures is generic to the honeycomb artificial spin ice geometry and whether the bar dimensions have an influence on its onset temperature. The EPSRC (Grant No. EP/G004765/1; Grant No. EP/L504786/1) and the Leverhulme Trust (Grant No. RPG 2012-692) funded this scientific work.

  4. Computational Chemistry of Cyclopentane Low Temperature Oxidation

    KAUST Repository

    El Rachidi, Mariam


    Cycloalkanes are significant constituents of conventional fossil fuels, but little is known concerning their combustion chemistry and kinetics, particularly at low temperatures. This study investigates the pressure dependent kinetics of several reactions occurring during low-temperature cyclopentane combustion using theoretical chemical kinetics. The reaction pathways of the cyclopentyl + O2 adduct is traced to alkylhydroperoxide, cyclic ether, β-scission and HO2 elimination products. The calculations are carried out at the UCCSD(T)-F12b/cc-pVTZ-F12//M06-2X/6-311++G(d,p) level of theory. The barrierless entrance channel is treated using variable-reaction-coordinate transition state theory (VRC-TST) at the CASPT2(7e,6o) level of theory, including basis set, geometry relaxation and ZPE corrections. 1-D time-dependent multiwell master equation analysis is used to determine pressure-and temperature-dependent rate parameters of all investigated reactions. Tunneling corrections are included using Eckart barriers. Comparison with cyclohexane is used to elucidate the effect of ring size on the low temperature reactivity of naphthenes. The rate coefficients reported herein are suitable for use in cyclopentane and methylcyclopentane combustion models, even below ~900 K, where ignition is particularly sensitive to these pressure-dependent values.

  5. Neutron moderation at very low temperatures (1691)

    International Nuclear Information System (INIS)

    Lacaze, A.


    Starting from Harwell experiment carried out inside a low-power reactor, we intended to maintain a liquid hydrogen cell in a channel of the EL3 reactor (at Saclay) whose thermal neutrons flux is 10 14 neutrons/cm 2 /s. We tried to work out a device giving off an important beam of cold neutrons and able to operate in a way as automatic as possible during many consecutive day without a stop. Several circuits have already been achieved at very low temperatures but they brought out volumes and fluxes much lower than those we used this time. The difficulties we have met in carrying out such a device arose on the one hand from the very high energy release to which any kind of experiment is inevitably submitted when placed near the core of the reactor, on the other, hand from the very little room which is available in experimental channels of reactors. In such condition, it is necessary to use a moderator as effective as possible. This study is divided into three parts ; in the first part, we try to determine: a) conditions in which moderation takes place, hence the volume of the cell; b) materials likely to be used at low temperature and in pile; c) cooling system; hence we had to study fluid flow conditions at very low temperatures in very long ducts. The second part is devoted to the description of the device. The third part ventilates the results we have obtained. (author) [fr

  6. Optimal quantum learning of a unitary transformation

    International Nuclear Information System (INIS)

    Bisio, Alessandro; Chiribella, Giulio; D'Ariano, Giacomo Mauro; Facchini, Stefano; Perinotti, Paolo


    We address the problem of learning an unknown unitary transformation from a finite number of examples. The problem consists in finding the learning machine that optimally emulates the examples, thus reproducing the unknown unitary with maximum fidelity. Learning a unitary is equivalent to storing it in the state of a quantum memory (the memory of the learning machine) and subsequently retrieving it. We prove that, whenever the unknown unitary is drawn from a group, the optimal strategy consists in a parallel call of the available uses followed by a 'measure-and-rotate' retrieving. Differing from the case of quantum cloning, where the incoherent 'measure-and-prepare' strategies are typically suboptimal, in the case of learning the 'measure-and-rotate' strategy is optimal even when the learning machine is asked to reproduce a single copy of the unknown unitary. We finally address the problem of the optimal inversion of an unknown unitary evolution, showing also in this case the optimality of the 'measure-and-rotate' strategies and applying our result to the optimal approximate realignment of reference frames for quantum communication.

  7. Low Temperature Synthesis of Magnesium Aluminate Spinel

    International Nuclear Information System (INIS)

    Lebedovskaya, E.G.; Gabelkov, S.V.; Litvinenko, L.M.; Logvinkov, D.S.; Mironova, A.G.; Odejchuk, M.A.; Poltavtsev, N.S.; Tarasov, R.V.


    The low-temperature synthesis of magnesium-aluminum spinel is carried out by a method of thermal decomposition in combined precipitated hydrates. The fine material of magnesium-aluminium spinel with average size of coherent dispersion's area 4...5 nanometers is obtained. Magnesium-aluminum spinel and initial hydrates were investigated by methods of the differential thermal analysis, the x-ray phase analysis and measurements of weight loss during the dehydration and thermal decomposition. It is established that synthesis of magnesium-aluminum spinel occurs at temperature 300 degree C by method of the x-ray phase analysis

  8. Investigations of Low Temperature Time Dependent Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Van der Sluys, W A; Robitz, E S; Young, B A; Bloom, J


    The objective of this project was to investigate metallurgical and mechanical phenomena associated with time dependent cracking of cold bent carbon steel piping at temperatures between 327 C and 360 C. Boiler piping failures have demonstrated that understanding the fundamental metallurgical and mechanical parameters controlling these failures is insufficient to eliminate it from the field. The results of the project consisted of the development of a testing methodology to reproduce low temperature time dependent cracking in laboratory specimens. This methodology was used to evaluate the cracking resistance of candidate heats in order to identify the factors that enhance cracking sensitivity. The resultant data was integrated into current available life prediction tools.

  9. Low temperature waste form process intensification

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Cozzi, A. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hansen, E. K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hill, K. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    This study successfully demonstrated process intensification of low temperature waste form production. Modifications were made to the dry blend composition to enable a 50% increase in waste concentration, thus allowing for a significant reduction in disposal volume and associated costs. Properties measurements showed that the advanced waste form can be produced using existing equipment and processes. Performance of the waste form was equivalent or better than the current baseline, with approximately double the amount of waste incorporation. The results demonstrate the feasibility of significantly accelerating low level waste immobilization missions across the DOE complex and at environmental remediation sites worldwide.

  10. Low temperature anodic bonding to silicon nitride

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Bouaidat, Salim


    Low-temperature anodic bonding to stoichiometric silicon nitride surfaces has been performed in the temperature range from 3508C to 4008C. It is shown that the bonding is improved considerably if the nitride surfaces are either oxidized or exposed to an oxygen plasma prior to the bonding. Both bulk...... and thin-film glasses were used in the bonding experiments. Bond quality was evaluated using a tensile test on structured dies. The effect of oxygen-based pre-treatments of the nitride surface on the bond quality has been evaluated. Bond strengths up to 35 Nrmm2 and yields up to 100% were obtained....

  11. Low Temperature MOCVD-Processed Alumina Coatings


    Gleizes, Alain; Sovar, Maria-Magdalena; Samélor, Diane; Vahlas, Constantin


    We first present a Review about the preparation of alumina as thin films by the technique of MOCVD at low temperature (550°C and below). Then we present our results about thin films prepared by the low pressure MOCVD technique, using aluminium tri-isopropoxide as a source, and characterized by elemental analysis (EMPA, EDS, ERDA, RBS), FTIR, XRD and TGA. The films were grown in a horizontal, hot-wall reactor, with N2 as a carrier gas either pure or added with water vapour. The deposition t...

  12. Low Temperature Decomposition Rates for Tetraphenylborate Ion

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.D.


    Previous studies indicated that palladium is catalyzes rapid decomposition of alkaline tetraphenylborate slurries. Additional evidence suggest that Pd(II) reduces to Pd(0) during catalyst activation. Further use of tetraphenylborate ion in the decontamination of radioactive waste may require removal of the catalyst or cooling to temperatures at which the decomposition reaction proceeds slowly and does not adversely affect processing. Recent tests showed that tetraphenylborate did not react appreciably at 25 degrees Celsius over six months suggesting the potential to avoid the decomposition at low temperatures. The lack of reaction at low temperature could reflect very slow kinetics at the lower temperature, or may indicate a catalyst ''deactivation'' process. Previous tests in the temperature range 35 to 70 degrees Celsius provided a low precision estimate of the activation energy of the reaction with which to predict the rate of reaction at 25 percent Celsius. To understand the observations at 25 degrees Celsius, experiments must separate the catalyst activation step and the subsequent reaction with TPB. Tests described in this report represent an initial attempt to separate the two steps and determine the rate and activation energy of the reaction between active catalyst and TPB. The results of these tests indicate that the absence of reaction at 25 degrees Celsius was caused by failure to activate the catalyst or the presence of a deactivating mechanism. In the presence of activated catalyst, the decomposition reaction rate is significant.

  13. Extreme low temperature tolerance in woody plants

    Directory of Open Access Journals (Sweden)

    George Richard Strimbeck


    Full Text Available Woody plants in boreal to arctic environments and high mountains survive prolonged exposure to temperatures below -40˚C and minimum temperatures below -60˚C, and laboratory tests show that many of these species can also survive immersion in liquid nitrogen at -196˚C. Studies of biochemical changes that occur during acclimation, including recent proteomic and metabolomic studies, have identified changes in carbohydrate and compatible solute concentrations, membrane lipid composition, and proteins, notably dehydrins, that may have important roles in survival at extreme low temperature. Consideration of the biophysical mechanisms of membrane stress and strain lead to the following hypotheses for cellular and molecular mechanisms of survival at extreme low temperature: 1. Changes in lipid composition stabilize membranes at temperatures above the lipid phase transition temperature (-20 to 30˚C, preventing phase changes that result in irreversible injury. 2. High concentrations of oligosaccharides promote vitrification or high viscosity in the cytoplasm in freeze-dehydrated cells, which would prevent deleterious interactions between membranes. 3. Dehydrins bind membranes and further promote vitrification or act stearically to prevent membrane-membrane interactions.

  14. Behaviour of elastomeric seals at low temperature

    International Nuclear Information System (INIS)

    Weise, H.P.; Kowalewsky, H.; Wenz, R.


    The properties of elastomer O-ring seals (Viton, silicone rubber, EPDM) at low temperature have been investigated by measuring the gas leakage rate and the sealing force during thermal cycling between +20degC and -70degC. For all materials it has been found that at a well defined (critical) temperature the leakage rate sharply rises from permeation level to a high value which is determined by gas streaming through the leak path between the O-ring and the flange surfaces arising from thermal contraction of the elastomer in the glassy state. At the critical temperature the sealing force has been found to be zero or even negative due to adhesion between the elastomer material and the flanges. For all seals the critical temperature is well below the glass transition of the elastomer and also significantly below the temperature where the compression set becomes 100 %. Warming up the sealing system restores leak tightness. Low temperature cycle of elastomeric seals have been found to be entirely reversible. (author)

  15. Low-temperature Condensation of Carbon (United States)

    Krasnokutski, S. A.; Goulart, M.; Gordon, E. B.; Ritsch, A.; Jäger, C.; Rastogi, M.; Salvenmoser, W.; Henning, Th.; Scheier, P.


    Two different types of experiments were performed. In the first experiment, we studied the low-temperature condensation of vaporized graphite inside bulk liquid helium, while in the second experiment, we studied the condensation of single carbon atoms together with H2, H2O, and CO molecules inside helium nanodroplets. The condensation of vaporized graphite leads to the formation of partially graphitized carbon, which indicates high temperatures, supposedly higher than 1000°C, during condensation. Possible underlying processes responsible for the instant rise in temperature during condensation are discussed. This suggests that such processes cause the presence of partially graphitized carbon dust formed by low-temperature condensation in the diffuse interstellar medium. Alternatively, in the denser regions of the ISM, the condensation of carbon atoms together with the most abundant interstellar molecules (H2, H2O, and CO), leads to the formation of complex organic molecules (COMs) and finally organic polymers. Water molecules were found not to be involved directly in the reaction network leading to the formation of COMs. It was proposed that COMs are formed via the addition of carbon atoms to H2 and CO molecules ({{C}}+{{{H}}}2\\to {HCH},{HCH}+{CO}\\to {{OCCH}}2). Due to the involvement of molecular hydrogen, the formation of COMs by carbon addition reactions should be more efficient at high extinctions compared with the previously proposed reaction scheme with atomic hydrogen.

  16. Antimisting kerosene: Low temperature degradation and blending (United States)

    Yavrouian, A.; Parikh, P.; Sarohia, V.


    The inline filtration characteristics of freshly blended and degraded antimisting fuels (AMK) at low temperature are examined. A needle valve degrader was modified to include partial recirculation of degraded fuel and heat addition in the bypass loop. A pressure drop across the needle valve of up to 4,000 psi was used. The pressure drop across a 325 mesh filter screen placed inline with the degrader and directly downstream of the needle valve was measured as a function of time for different values of pressure drop across the needle valve. A volume flux of 1 gpm/sq in was employed based on the frontal area of the screen. It was found that, at ambient temperatures, freshly blended AMK fuel could be degraded using a single pass degradation at 4,000 psi pressure drop across the needle valve to give acceptable filterability performance. At fuel temperatures below -20 C, degradation becomes increasingly difficult and a single pass technique results in unacceptable filtration performance. Recirculation of a fraction of the degraded fuel and heat addition in the bypass loop improved low temperature degradation performance. The problem is addressed of blending the AMK additive with Jet A at various base fuel temperatures.

  17. An Estimate of Shallow, Low-Temperature Geothermal Resources of the United States: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Mullane, Michelle; Gleason, Michael; McCabe, Kevin; Mooney, Meghan; Reber, Timothy; Young, Katherine R.


    Low-temperature geothermal resources in the United States potentially hold an enormous quantity of thermal energy, useful for direct use in residential, commercial and industrial applications such as space and water heating, greenhouse warming, pool heating, aquaculture, and low-temperature manufacturing processes. Several studies published over the past 40 years have provided assessments of the resource potential for multiple types of low-temperature geothermal systems (e.g. hydrothermal convection, hydrothermal conduction, and enhanced geothermal systems) with varying temperature ranges and depths. This paper provides a summary and additional analysis of these assessments of shallow (= 3 km), low-temperature (30-150 degrees C) geothermal resources in the United States, suitable for use in direct-use applications. This analysis considers six types of geothermal systems, spanning both hydrothermal and enhanced geothermal systems (EGS). We outline the primary data sources and quantitative parameters used to describe resources in each of these categories, and present summary statistics of the total resources available. In sum, we find that low-temperature hydrothermal resources and EGS resources contain approximately 8 million and 800 million TWh of heat-in-place, respectively. In future work, these resource potential estimates will be used for modeling of the technical and market potential for direct-use geothermal applications for the U.S. Department of Energy's Geothermal Vision Study.

  18. An Estimate of Shallow, Low-Temperature Geothermal Resources of the United States

    Energy Technology Data Exchange (ETDEWEB)

    Mullane, Michelle; Gleason, Michael; Reber, Tim; McCabe, Kevin; Mooney, Meghan; Young, Katherine R.


    Low-temperature geothermal resources in the United States potentially hold an enormous quantity of thermal energy, useful for direct use in residential, commercial and industrial applications such as space and water heating, greenhouse warming, pool heating, aquaculture, and low-temperature manufacturing processes. Several studies published over the past 40 years have provided assessments of the resource potential for multiple types of low-temperature geothermal systems (e.g. hydrothermal convection, hydrothermal conduction, and enhanced geothermal systems) with varying temperature ranges and depths. This paper provides a summary and additional analysis of these assessments of shallow (= 3 km), low-temperature (30-150 degrees C) geothermal resources in the United States, suitable for use in direct-use applications. This analysis considers six types of geothermal systems, spanning both hydrothermal and enhanced geothermal systems (EGS). We outline the primary data sources and quantitative parameters used to describe resources in each of these categories, and present summary statistics of the total resources available. In sum, we find that low-temperature hydrothermal resources and EGS resources contain approximately 8 million and 800 million TWh of heat-in-place, respectively. In future work, these resource potential estimates will be used for modeling of the technical and market potential for direct-use geothermal applications for the U.S. Department of Energy's Geothermal Vision Study.

  19. Quench of non-Markovian coherence in the deep sub-Ohmic spin-boson model: A unitary equilibration scheme


    Yao, Yao


    The deep sub-Ohmic spin-boson model shows a longstanding non-Markovian coherence at low temperature. Motivating to quench this robust coherence, the thermal effect is unitarily incorporated into the time evolution of the model, which is calculated by the adaptive time-dependent density matrix renormalization group algorithm combined with the orthogonal polynomials theory. Via introducing a unitary heating operator to the bosonic bath, the bath is heated up so that a majority portion of the bo...

  20. Radically Different Kinetics at Low Temperatures (United States)

    Sims, Ian


    The use of the CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme, or Reaction Kinetics in Uniform Supersonic Flow) technique coupled with pulsed laser photochemical kinetics methods has shown that reactions involving radicals can be very rapid at temperatures down to 10 K or below. The results have had a major impact in astrochemistry and planetology, as well as proving an exacting test for theory. The technique has also been applied to the formation of transient complexes of interest both in atmospheric chemistry and combustion. Until now, all of the chemical reactions studied in this way have taken place on attractive potential energy surfaces with no overall barrier to reaction. The F + H2 {→} HF + H reaction does possess a substantial energetic barrier ({\\cong} 800 K), and might therefore be expected to slow to a negligible rate at very low temperatures. In fact, this H-atom abstraction reaction does take place efficiently at low temperatures due entirely to tunneling. I will report direct experimental measurements of the rate of this reaction down to a temperature of 11 K, in remarkable agreement with state-of-the-art quantum reactive scattering calculations by François Lique (Université du Havre) and Millard Alexander (University of Maryland). It is thought that long chain cyanopolyyne molecules H(C2)nCN may play an important role in the formation of the orange haze layer in Titan's atmosphere. The longest carbon chain molecule observed in interstellar space, HC11N, is also a member of this series. I will present new results, obtained in collaboration with Jean-Claude Guillemin (Ecole de Chimie de Rennes) and Stephen Klippenstein (Argonne National Labs), on reactions of C2H, CN and C3N radicals (using a new LIF scheme by Hoshina and Endo which contribute to the low temperature formation of (cyano)polyynes. H. Sabbah, L. Biennier, I. R. Sims, Y. Georgievskii, S. J. Klippenstein, I. W. M. Smith, Science 317, 102 (2007). S. D. Le Picard, M

  1. The Low Temperature Microgravity Physics Experiments Project (United States)

    Holmes, Warren; Lai, Anthony; Croonquist, Arvid; Chui, Talso; Eraker, J. H.; Abbott, Randy; Mills, Gary; Mohl, James; Craig, James; Balachandra, Balu; hide


    The Low Temperature Microgravity Physics Facility (LTMPF) is being developed by NASA to provide long duration low temperature and microgravity environment on the International Space Station (ISS) for performing fundamental physics investigations. Currently, six experiments have been selected for flight definition studies. More will be selected in a two-year cycle, through NASA Research Announcement. This program is managed under the Low Temperature Microgravity Physics Experiments Project Office at the Jet Propulsion Laboratory. The facility is being designed to launch and returned to earth on a variety of vehicles including the HII-A and the space shuttle. On orbit, the facility will be connected to the Exposed Facility on the Japanese Experiment Module, Kibo. Features of the facility include a cryostat capable of maintaining super-fluid helium at a temperature of 1.4 K for 5 months, resistance thermometer bridges, multi-stage thermal isolation system, thermometers capable of pico-Kelvin resolution, DC SQUID magnetometers, passive vibration isolation, and magnetic shields with a shielding factor of 80dB. The electronics and software architecture incorporates two VME buses run using the VxWorks operating system. Technically challenging areas in the design effort include the following: 1) A long cryogen life that survives several launch and test cycles without the need to replace support straps for the helium tank. 2) The minimization of heat generation in the sample stage caused by launch vibration 3) The design of compact and lightweight DC SQUID electronics. 4) The minimization of RF interference for the measurement of heat at pico-Watt level. 5) Light weighting of the magnetic shields. 6) Implementation of a modular and flexible electronics and software architecture. The first launch is scheduled for mid-2003, on an H-IIA Rocket Transfer Vehicle, out of the Tanegashima Space Center of Japan. Two identical facilities will be built. While one facility is onboard

  2. Desalination by very low temperature nuclear heat

    International Nuclear Information System (INIS)

    Saari, Risto


    A new sea water desalination method has been developed: Nord-Aqua Vacuum Evaporation, which utilizes waste heat at a very low temperature. The requisite vacuum is obtained by the aid of a barometric column and siphon, and the dissolved air is removed from the vacuum by means of water flows. According to test results from a pilot plant, the process is operable if the waste heat exists at a temperature 7degC higher than ambient. The pumping energy which is then required is 9 kcal/kg, or 1.5% of the heat of vaporization of water. Calculations reveal that the method is economically considerably superior to conventional distilling methods. (author)

  3. Preparation of silver nanoparticles at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Mini, E-mail: [Centre of Environmental Science, Department of Botany, University of Allahabad, Allahabad, U.P. (India); Chauhan, Pratima, E-mail: [Department of Physics, University of Allahabad, Allahabad U.P. (India)


    Silver from ancient time is used as antimicrobial agent in the bulk form but now with the advancement in nanotechnology silver in the form of nanoparticles shown potential effect against microbes which make us easy to fight with many diseases plants and animals. In this work silver nanoparticles were synthesized by chemical routes using sodium borohydride as reducing agent at low temperature. The particles were characterized through UV-Visible spectroscopy as well as X-Ray Diffraction. The UV-visible spectra of silver nanoparticles exhibited absorption at 425 cm; the crystallite size of the particles is between 19nm to 39nm. EDAX graph shows two peaks of silver and oxygen. Water absorbed by silver nanoparticles was removed by the calcinations.

  4. Recrystallization of magnesium deformed at low temperatures

    International Nuclear Information System (INIS)

    Fromageau, R.; Pastol, J.L.; Revel, G.


    The recrystallization of magnesium was studied after rolling at temperatures ranging between 248 and 373 K. For zone refined magnesium the annealing behaviour as observed by electrical resistivity measurements showed two stages at about 250 K and 400 K due respectively to recrystallization and grain growth. The activation energy associated with the recrystallization stage was 0.75 +- 0.01 eV. In less pure magnesium, with nominal purity 99.99 and 99.9%, the recrystallization stage was decomposed into two substages. Activation energies were determined in relation with deformation temperature and purity. The magnesium of intermediate purity (99.99%) behaved similarly to the lowest purity metal when it was deformed at high temperature and to the purest magnesium when the deformation was made at low temperature. This behaviour was discussed in connection with the theories of Luecke and Cahn. (Auth.)

  5. Studies of helium breakdown at low temperatures

    International Nuclear Information System (INIS)

    May, D.


    For designing cryogenic installations the breakdown strength of helium at temperatures near absolute zero has to be known. Various breakdown strengths are reported in literature concerning liquid helium. It is the objective of these studies to find an explanation for the different breakdown strengths by suitable variation of parameters. Various electrode materials commonly used in low temperature techniques with different sample preparation are used to measure breakdown strength of liquid helium in the gap range from 0.5 mm to 3 mm. A substantial influence of roughness, oxide layer and microcracks on strength is revealed. These terms are summarized and defined as 'condition of the electrode surface'. Taking this into account the various breakdown strengths can be qualitatively explained. Based on these results breakdown strength in supercritical high density helium is examined. A Paschen-curve can be given for this thermodynamical region. (orig./WL) [de

  6. On Low-temperature Polyamorphous transformations

    International Nuclear Information System (INIS)

    Bakay, A.S.


    A theory of polyamorphous transformations in glasses is constructed in the framework of a model of heterophase fluctuations with allowance for the fact that a glass inherits the short- and intermediate-range order from the liquid. A multicomponent order parameter describing the concentration of fluctuons with different types of short-range order is introduced, along with the concepts of isoconfigurational and non-isoconfigurational transitions in the glass. Taking the nonergodicity, nonequilibrium, and multiplicity of structural states of a glass into account leads to a kinetic criterion of observability of polyamorphism of a glass. As an example, a theory is constructed for the low-temperature first-order phase transition in an orientational glass based on doped fullerite. The relaxation processes of this system are described, including the subsystem of tunneling states. The possibility of a hierarchy of polyamorphous transformations in a glass is discussed

  7. Shock waves in helium at low temperatures

    International Nuclear Information System (INIS)

    Liepmann, H.W.; Torczynski, J.R.


    Results are reported from studies of the properties of low temperature He-4 using shock waves as a probe. Ideal shock tube theory is used to show that sonic speeds of Mach 40 are attainable in He at 300 K. Viscosity reductions at lower temperatures minimize boundary layer effects at the side walls. A two-fluid model is described to account for the phase transition which He undergoes at temperatures below 2.2 K, after which the quantum fluid (He II) and the normal compressed superfluid (He I) coexist. Analytic models are provided for pressure-induced shocks in He I and temperature-induced shock waves (called second sound) which appear in He II. The vapor-fluid interface of He I is capable of reflecting second and gasdynamic sound shocks, which can therefore be used as probes for studying phase transitions between He I and He II. 17 references

  8. Low temperature catalyst system for methanol production (United States)

    Sapienza, R.S.; Slegeir, W.A.; O'Hare, T.E.


    This patent discloses a catalyst and process useful at low temperatures (150/sup 0/C) and preferably in the range 80 to 120/sup 0/C used in the production of methanol from carbon monoxide and hydrogen. The catalyst components are used in slurry form and comprise (1) a complex reducing agent derived from the component structure NaH-ROH-M(OAc)/sub 2/ where M is selected from the group consisting of Ni, Pd, and Co and R is a lower alkyl group containing 1 to 6 carbon atoms and (2) a metal carbonyl of a group VI (Mo, Cr, W) metal. For the first component, Nic is preferred (where M = Ni and R = tertiary amyl). For the second component, Mo(CO)/sub 6/ is preferred. The mixture is subjected to a conditioning or activating step under temperature and pressure, similar to the parameters given above, to afford the active catalyst.

  9. Evaluation of Low Temperature CO Removal Catalysts (United States)

    Monje, Oscar


    CO removal from spacecraft gas streams was evaluated for three commercial, low temperature oxidation catalysts: Carulite 300, Sofnocat 423, and Hamilton Sundstrand Pt1. The catalysts were challenged with CO concentrations (1-100 ppm) under dry and wet (50% humidity) conditions using 2-3 % O2. CO removal and CO2 concentration were measured at constant feed composition using a FTIR. Water vapor affected the CO conversion of each catalyst differently. An initial screening found that Caulite 300 could not operate in humid conditions. The presence of water vapor affected CO conversion of Sofnocat 423 for challenge concentrations below 40 ppm. The conversion of CO by Sofnocat 423 was 80% at CO concentrations greater than 40 ppm under both dry and moist conditions. The HS Pt1 catalyst exhibited CO conversion levels of 100% under both dry and moist conditions.

  10. Low-Temperature Properties of Silver (United States)

    Smith, David R.; Fickett, F. R.


    Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability. PMID:29151733

  11. Low-temperature geothermal resources of Washington

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, J.E. [Washington State Dept. of Natural Resources, Olympia, WA (United States). Div. of Geology and Earth Resources; Bloomquist, R.G. [Washington State Energy Office, Olympia, WA (United States)


    This report presents information on the location, physical characteristics, and water chemistry of low-temperature geothermal resources in Washington. The database includes 941 thermal (>20C or 68F) wells, 34 thermal springs, lakes, and fumaroles, and 238 chemical analyses. Most thermal springs occur in the Cascade Range, and many are associated with stratovolcanoes. In contrast, 97 percent of thermal wells are located in the Columbia Basin of southeastern Washington. Some 83.5 percent are located in Adams, Benton, Franklin, Grant, Walla Walla, and Yakima Counties. Yakima County, with 259 thermal wells, has the most. Thermal wells do not seem to owe their origin to local sources of heat, such as cooling magma in the Earth`s upper crust, but to moderate to deep circulation of ground water in extensive aquifers of the Columbia River Basalt Group and interflow sedimentary deposits, under the influence of a moderately elevated (41C/km) average geothermal gradient.

  12. Low Temperature Waste Immobilization Testing Vol. I

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Schweiger, Michael J.; Westsik, Joseph H.; Hrma, Pavel R.; Smith, D. E.; Gallegos, Autumn B.; Telander, Monty R.; Pitman, Stan G.


    The Pacific Northwest National Laboratory (PNNL) is evaluating low-temperature technologies to immobilize mixed radioactive and hazardous waste. Three waste forms—alkali-aluminosilicate hydroceramic cement, “Ceramicrete” phosphate-bonded ceramic, and “DuraLith” alkali-aluminosilicate geopolymer—were selected through a competitive solicitation for fabrication and characterization of waste-form properties. The three contractors prepared their respective waste forms using simulants of a Hanford secondary waste and Idaho sodium bearing waste provided by PNNL and characterized their waste forms with respect to the Toxicity Characteristic Leaching Procedure (TCLP) and compressive strength. The contractors sent specimens to PNNL, and PNNL then conducted durability (American National Standards Institute/American Nuclear Society [ANSI/ANS] 16.1 Leachability Index [LI] and modified Product Consistency Test [PCT]) and compressive strength testing (both irradiated and as-received samples). This report presents the results of these characterization tests.

  13. The effect of low temperature cryocoolers on the development of low temperature superconducting magnets

    International Nuclear Information System (INIS)

    Green, Michael A.


    The commercial development of reliable 4 K cryocoolers improves the future prospects for magnets made from low temperature superconductors (LTS). The hope of the developers of high temperature superconductors (HTS) has been to replace liquid helium cooled LTS magnets with HTS magnets that operate at or near liquid nitrogen temperature. There has been limited success in this endeavor, but continued problems with HTS conductors have greatly slowed progress toward this goal. The development of cryocoolers that reliably operate below 4 K will allow magnets made from LTS conductor to remain very competitive for many years to come. A key enabling technology for the use of low temperature cryocoolers on LTS magnets has been the development of HTS leads. This report describes the characteristics of LTS magnets that can be successfully melded to low-temperature cryocoolers. This report will also show when it is not appropriate to consider the use of low-temperature cryocoolers to cool magnets made with LTS conductor. A couple of specific examples of LTS magnets where cryocoolers can be used are given

  14. HTPro: Low-temperature Surface Hardening of Stainless Steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Somers, Marcel A. J.


    Low-temperature surface hardening of stainless steel provides the required performance properties without affecting corrosion resistance.......Low-temperature surface hardening of stainless steel provides the required performance properties without affecting corrosion resistance....

  15. Generalized unitaries and the Picard group

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 116; Issue 4 ... After discussing some basic facts about generalized module maps, we use the representation theory of the algebra B B a ( E ) of adjointable operators on a Hilbert B -module to show that the quotient of the group of generalized unitaries on  ...

  16. Generalized unitaries and the Picard group

    Indian Academy of Sciences (India)

    Our motivation for these notes is to study one-parameter groups of generalized unitaries and to prepare the terrain for the ... have in mind the tensor product will be the key ingredient of the approach. We comment on these ideas at ... The two properties of iϕ mentioned before Observation 1.2 motivate the following definition.

  17. Unitary transformation method for solving generalized Jaynes ...

    Indian Academy of Sciences (India)

    Abstract. Two fully quantized generalized Jaynes–Cummings models for the interac- tion of a two-level atom with radiation field are treated, one involving intensity dependent coupling and the other involving multiphoton interaction between the field and the atom. The unitary transformation method presented here not only ...

  18. Remarks on unitary representations of Poincare group

    International Nuclear Information System (INIS)

    Burzynski, A.


    In this paper the elementary review of methods and notions using in the theory of unitary representations of Poincare group is included. The Poincare group is a basic group for relativistic quantum mechanics. Our aim is to introduce the reader into some problems of quantum physics, which are difficult approachable for beginners. (author)

  19. Chiral unitary theory: Application to nuclear problems

    Indian Academy of Sciences (India)

    PRAMANA c Indian Academy of Sciences. Vol. 57, Nos 2 & 3. — journal of. Aug. & Sept. 2001 physics pp. 417–431. Chiral unitary theory: Application to nuclear problems. E OSET ... Institute of High Energy Physics, Academia Sinica, Beijing, China. 3. Departamento ...... [57] D B Kaplan and A E Nelson, Phys. Lett. B175, 57 ...

  20. Local unitary invariants for multipartite quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Vrana, Peter, E-mail: [Department of Theoretical Physics, Institute of Physics, Budapest University of Technology and Economics, H-1111 Budapest (Hungary)


    A method is presented to obtain local unitary invariants for multipartite quantum systems consisting of fermions or distinguishable particles. The invariants are organized into infinite families, in particular, the generalization to higher dimensional single-particle Hilbert spaces is straightforward. Many well-known invariants and their generalizations are also included.

  1. Chiral unitary theory: Application to nuclear problems

    Indian Academy of Sciences (India)

    Sept. 2001 physics pp. 417–431. Chiral unitary theory: Application to nuclear problems ... parameters which are adjusted to the data or alternatively derived in some models. Chiral perturbation theory up ..... consistent with a large broadening of the and more experimental studies are under way at GSI (HADES collaboration) ...

  2. Low temperature humidification dehumidification desalination process

    International Nuclear Information System (INIS)

    Al-Enezi, Ghazi; Ettouney, Hisham; Fawzy, Nagla


    The humidification dehumidification desalination process is viewed as a promising technique for small capacity production plants. The process has several attractive features, which include operation at low temperature, ability to utilize sustainable energy sources, i.e. solar and geothermal, and requirements of low technology level. This paper evaluates the characteristics of the humidification dehumidification desalination process as a function of operating conditions. A small capacity experimental system is used to evaluate the process characteristics as a function of the flow rate of the water and air streams, the temperature of the water stream and the temperature of the cooling water stream. The experimental system includes a packed humidification column, a double pipe glass condenser, a constant temperature water circulation tank and a chiller for cooling water. The water production is found to depend strongly on the hot water temperature. Also, the water production is found to increase upon the increase of the air flow rate and the decrease of the cooling water temperature. The measured air and water temperatures, air relative humidity and the flow rates are used to calculate the air side mass transfer coefficient and the overall heat transfer coefficient. Measured data are found to be consistent with previous literature results

  3. Low temperature catalysts for methanol production (United States)

    Sapienza, Richard S.; Slegeir, William A.; O'Hare, Thomas E.; Mahajan, Devinder


    A catalyst and process useful at low temperatures (below about C.) and preferably in the range C. used in the production of methanol from carbon monoxide and hydrogen is disclosed. The catalyst is used in slurry form and comprises a complex reducing agent derived from the component structure NaH--RONa--M(OAc).sub.2 where M is selected from the group consisting of Ni, Pd, and Co and R is a lower alkyl group containing 1-6 carbon atoms. This catalyst is preferably used alone but is also effective in combination with a metal carbonyl of a group VI (Mo, Cr, W) metal. The preferred catalyst precursor is Nic (where M=Ni and R=tertiary amyl). Mo(CO).sub.6 is the preferred metal carbonyl if such component is used. The catalyst is subjected to a conditioning or activating step under temperature and pressure, similar to the parameters given above, to afford the active catalyst.

  4. Low temperature catalysts for methanol production (United States)

    Sapienza, R.S.; Slegeir, W.A.; O'Hare, T.E.; Mahajan, D.


    A catalyst and process useful at low temperatures (below about 160/sup 0/C) and preferably in the range 80 to 120/sup 0/C used in the production of methanol from carbon monoxide and hydrogen is disclosed. The catalyst is used in slurry form and comprises a complex reducing agent derived from the component structure NaH-RONa-M(OAc)/sub 2/ where M is selected from the group consisting of Ni, Pd, and Co and R is a lower alkyl group containing 1 to 6 carbon atoms. This catalyst is preferably used alone but is also effective in combination with a metal carbonyl of a group VI (Mo, Cr, W) metal. The preferred catalyst precursor is Nic (where M = Ni and R = tertiary amyl). Mo(CO)/sub 6/ is the preferred metal carbonyl if such component is used. The catalyst is subjected to a conditioning or activating step under temperature and pressure, similar to the parameters given above, to afford the active catalyst.

  5. Low Temperature Catalyst for NH3 Removal (United States)

    Monje, Oscar; Melendez, Orlando


    Air revitalization technologies maintain a safe atmosphere inside spacecraft by the removal of C02, ammonia (NH3), and trace contaminants. NH3 onboard the International Space Station (ISS) is produced by crew metabolism, payloads, or during an accidental release of thermal control refrigerant. Currently, the ISS relies on removing NH3 via humidity condensate and the crew wears hooded respirators during emergencies. A different approach to cabin NH3 removal is to use selective catalytic oxidation (SCO), which builds on thermal catalytic oxidation concepts that could be incorporated into the existing TCCS process equipment architecture on ISS. A low temperature platinum-based catalyst (LTP-Catalyst) developed at KSC was used for converting NH3 to H20 and N2 gas by SCO. The challenge of implementing SCO is to reduce formation of undesirable byproducts like NOx (N20 and NO). Gas mixture analysis was conducted using FTIR spectrometry in the Regenerable VOC Control System (RVCS) Testbed. The RVCS was modified by adding a 66 L semi-sealed chamber, and a custom NH3 generator. The effect of temperature on NH3 removal using the LTP-Catalyst was examined. A suitable temperature was found where NH3 removal did not produce toxic NO, (NO, N02) and N20 formation was reduced.

  6. Ultralightweight low-temperature fused Zerodur mirror (United States)

    Miller, Jennifer; Crowe, David A.; Clark, Patrick; Marker, Alexander J.


    The performance and utility of optical systems can be significantly improved by using lightweight stable mirror components. Such components have been incorporated into a mirror assembly through a process that utilizes low temperature fusion to bond low CTE faceplates onto a lightweight core structure. The core structure is fabricated using an abrasive waterjet cutting technique that enables the designer to optimize core geometry to enhance the structural performance of the blank. The faceplates are bonded to the lightweight core resulting in a stiff structural mirror. A 15.125 inch Zerodur mirror was fabricated using this unique process and subjected to a test program to measure the optical stability of the mirror in support of either space-based applications. Strength testing was performed to verify the integrity of the fused joints and determine appropriate design allowable stress. A thermal test program was designed to assess performance at various temperature extremes and a mechanical load test was run to verify the capability of the blank to withstand operational loads without degrading the optical surface. The surface figure of the part was measured before, during, and after a 200 degree F temperature cycle with no change in figure quality. In addition, the mirror was subjected to a 10 g load for ten minutes with no change in the figure quality.

  7. Active carbons from low temperature conversion chars

    International Nuclear Information System (INIS)

    Adebowale, K.O.; Bayer, E.


    Hulls obtained from the fruits of five tropical biomass have been subjected to low temperature conversion process and their chars activated by partial physical gasification to produce active carbons. The biomass are T. catappa, B. nitida, L leucophylla, D. regia and O. martiana. The bulk densities of the samples ranged from 0.32 3 to 0.52 3 . Out of the samples T. catappa recorded the highest cellulose content (41.9 g.100g -1 ), while O. martiana contained the highest lignin content (40.7 g.100g -1 ). The ash of the samples were low (0.5 - 4.4%). The percentage of char obtained after conversion were high (33.7% - 38.6%). Active carbons obtained from T. catappa, D. regia and O. martiana, recorded high methylene blue numbers and iodine values. They also displayed good micro- and mesostructural characteristics. Micropore volume (V micro ) was between 0.33cm 3 .g -1 - 0.40cm 3 .g -1 , while the mesopore volume(V meso ) was between 0.05 cm 3 .g -1 - 0.07 cm 3 .g -1 . The BET specific surface exceeds 1000 m 2 .g -1 . All these values compared favourably with high grade commercial active carbons. (author)

  8. Some experiments in low-temperature thermometry

    International Nuclear Information System (INIS)

    Fogle, W.E.


    A powdered cerous magnesium nitrate (CMN) temperature scale has been developed in the 0.016 to 3.8 K region which represents an interpolation between the 3 He/ 4 He (T 62 /T 58 ) vapor pressure scale and absolute temperatures in the millikelvin region as determined with a 60 Co in hcp Co nuclear orientation thermometer (NOT). Both ac and dc susceptibility thermometers were used in these experiments. The ac susceptibility of a 13 mg CMN-oil slurry was measured with a mutual inductance bridge employing a SQUID null detector while the dc susceptibility of a 3 mg slurry was measured with a SQUID/flux transformer combination. To check the internal consistency of the NOT, γ-ray intensities were measured both parallel and perpendicular to the Co crystal c-axis. The independent temperatures determined in this fashion were found to agree to within experimental error. For the CMN thermometers employed in these experiments, the susceptibility was found to obey a Curie-Weiss law with a Weiss constant of Δ = 1.05 +- 0.1 mK. The powdered CMN scale in the 0.05 to 1.0 K region was transferred to two germanium resistance thermometers for use in low-temperature specific heat measurements. The integrity of the scale was checked by examining the temperature dependence of the specific heat of high purity copper in the 0.1 to 1 K region. In more recent experiments in this laboratory, the scale was also checked by a comparison with the National Bureau of Standards cryogenic temperature scale (NBS-CTS-1). The agreement between the two scales in the 99 to 206 mK region was found to be on the order of the stated accuracy of the NBS scale

  9. Stability of a Unitary Bose Gas (United States)

    Fletcher, Richard J.; Gaunt, Alexander L.; Navon, Nir; Smith, Robert P.; Hadzibabic, Zoran


    We study the stability of a thermal K39 Bose gas across a broad Feshbach resonance, focusing on the unitary regime, where the scattering length a exceeds the thermal wavelength λ. We measure the general scaling laws relating the particle-loss and heating rates to the temperature, scattering length, and atom number. Both at unitarity and for positive a≪λ we find agreement with three-body theory. However, for a<0 and away from unitarity, we observe significant four-body decay. At unitarity, the three-body loss coefficient, L3∝λ4, is 3 times lower than the universal theoretical upper bound. This reduction is a consequence of species-specific Efimov physics and makes K39 particularly promising for studies of many-body physics in a unitary Bose gas.

  10. Unitary representations and harmonic analysis an introduction

    CERN Document Server

    Sugiura, M


    The principal aim of this book is to give an introduction to harmonic analysis and the theory of unitary representations of Lie groups. The second edition has been brought up to date with a number of textual changes in each of the five chapters, a new appendix on Fatou''s theorem has been added in connection with the limits of discrete series, and the bibliography has been tripled in length.

  11. Unitary Quantum Lattice Algorithms for Turbulence (United States)


    AFRL-AFOSR-VA-TR-2016-0191 Unitary Quantum Lattice Algorithms for Turbulence George Vahala COLLEGE OF WILLIAM & MARY THE Final Report 05/23/2016...5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) College of William & Mary 261... Richmond Rd Williamsburg, VA 23185-4042 8. PERFORMING ORGANIZATION REPORT NUMBER AFOSR-FA9550-3 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS

  12. Grism manufacturing by low temperature mineral bonding (United States)

    Kalkowski, G.; Grabowski, K.; Harnisch, G.; Flügel-Paul, T.; Zeitner, U.; Risse, S.


    By uniting a grating with a prism to a GRISM compound, the optical characteristics of diffractive and refractive elements can be favorably combined to achieve outstanding spectral resolution features. Ruling the grating structure into the prism surface is common for wavelengths around 1 μm and beyond, while adhesive bonding of two separate parts is generally used for shorter wavelengths and finer structures. We report on a manufacturing approach for joining the corresponding glass elements by the technology of hydrophilic direct bonding. This allows to manufacture the individual parts separately and subsequently combine them quasimonolithically by generating stiff and durable bonds of vanishing thickness, high strength and excellent transmission. With this approach for GRISM bonding, standard direct-write- or mask-lithography equipment may be used for the fabrication of the grating structure and the drawbacks of adhesive bonding (thermal mismatch, creep, aging) are avoided. The technology of hydrophilic bonding originates from "classical" optical contacting [1], but has been much improved and perfected during the last decades in the context of 3-dimensinal stacking Si-wafers for microelectronic applications [2]. It provides joins through covalent bonds of the Si-O-Si type at the nanometer scale, i.e. the elementary bond type in many minerals and glasses. The mineral nature of the bond is perfectly adapted to most optical materials and the extremely thin bonding layers generated with this technology are well suited for transmission optics. Creeping under mechanical load, as commonly observed with adhesive bonding, is not an issue. With respect to diffusion bonding, which operates at rather high temperatures close to the glass transition or crystal melting point, hydrophilic bonding is a low temperature process that needs only moderate heating. This facilitates provision of handling and alignment means for the individual parts during the set-up stages and greatly

  13. Low Temperature Trapping: from Reactions to Spectroscopy (United States)

    Schlemmer, S.; Asvany, O.; Brunken, S.


    The kinetics of ion - molecule reactions are investigated in higher-order multipole traps by observation of the temporal evolution of mass selected parent ions in the presence of a neutral reaction partner. Rate coeffients for fast reactions (proceeding at collision rate) and very slow reactions (taking millions of collisions) are determined over a wide range of temperatures. Endothermic or hindered reactions can be promoted by excitation of the ion via absorption of a photon. Scanning the photon energy while detecting the number of product ions establishes an action spectroscopy method which we developed over the last 10-15 years and termed LIR: laser or light induced reactions. The main advantages of LIR are mass selection of the parent ion and low temperature conditions in the trap. Long storage times in combination with a near unity detection efficiency make LIR one of the most sensitive spectroscopy methods. The status quo of LIR will be discussed on selected examples. Recent measurements are concerned with ro-vibrational spectra of CH_2D^+ and CH_5^+ at highest resolution using cw OPO radiation. In the particular case of CH_5^+, the lines in the mid IR have been measured at a nominal temperature of 10 K and a frequency comb has been used for absolute calibration. Line positions can be determined to an accuracy which shall enable us in the future to obtain rotational spectra in a THz-IR double resonance approach. We tested the feasibility of this two photon method recently on H_2D^+. S. Schlemmer, T. Kuhn, E. Lescop, and D. Gerlich, Laser excited N_2^+ in a 22-Pole Trap: Experimental Studies of Rotational Relaxation Processes, Int. J. Mass Spectrometry and Ion Processes, 185-187, 589-602, (1999), S.D. Ivanov, O. Asvany, A. Witt, E. Hugo, G. Mathias, B. Redlich, D. Marx and S. Schlemmer, Quantum-induced symmetry breaking explains infrared spectra of CH_5^+ isotopologues, Nature Chemistry, 2, 298-302 (2010) S. Gaertner, J. Krieg, A. Klemann, O. Asvany and S

  14. Low Temperature Surface Carburization of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Sunniva R; Heuer, Arthur H; Sikka, Vinod K


    Low-temperature colossal supersaturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels (SS) without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation. As a result, surface carbon concentrations in excess of 12 at. % are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility. LTCSS is a diffusional surface hardening process that provides a uniform and conformal hardened gradient surface with no risk of delamination or peeling. The treatment retains the austenitic phase and is completely non-magnetic. In addition, because parts are treated at low temperature, they do not distort or change dimensions. During this treatment, carbon diffusion proceeds into the metal at temperatures that constrain substitutional diffusion or mobility between the metal alloy elements. Though immobilized and unable to assemble to form carbides, chromium and similar alloying elements nonetheless draw enormous amounts of carbon into their interstitial spaces. The carbon in the interstitial spaces of the alloy crystals makes the surface harder than ever achieved before by more conventional heat treating or diffusion process. The carbon solid solution manifests a Vickers hardness often exceeding 1000 HV (equivalent to 70 HRC). This project objective was to extend the LTCSS treatment to other austenitic alloys, and to quantify improvements in fatigue, corrosion, and wear resistance. Highlights from the research include the following: • Extension of the applicability of the LTCSS process to a broad range of austenitic and duplex grades of steels • Demonstration of LTCSS ability for a variety of different component shapes and sizes • Detailed microstructural characterization of LTCSS-treated samples of 316L and other alloys

  15. Stable unitary integrators for the numerical implementation of continuous unitary transformations (United States)

    Savitz, Samuel; Refael, Gil


    The technique of continuous unitary transformations has recently been used to provide physical insight into a diverse array of quantum mechanical systems. However, the question of how to best numerically implement the flow equations has received little attention. The most immediately apparent approach, using standard Runge-Kutta numerical integration algorithms, suffers from both severe inefficiency due to stiffness and the loss of unitarity. After reviewing the formalism of continuous unitary transformations and Wegner's original choice for the infinitesimal generator of the flow, we present a number of approaches to resolving these issues including a choice of generator which induces what we call the "uniform tangent decay flow" and three numerical integrators specifically designed to perform continuous unitary transformations efficiently while preserving the unitarity of flow. We conclude by applying one of the flow algorithms to a simple calculation that visually demonstrates the many-body localization transition.

  16. Cryogenic Capacitors for Low-Temperature Power Systems Project (United States)

    National Aeronautics and Space Administration — TRS Technologies proposes to develop low-temperature multilayer ceramic capacitors (MLCCs) capable of operating at cyrogenic temperatures (<77K). These capacitors...

  17. Asymptotic gap probability distributions of the Gaussian unitary ensembles and Jacobi unitary ensembles

    Directory of Open Access Journals (Sweden)

    Shulin Lyu


    The σ function, namely, the derivative of the log of the smallest eigenvalue distributions of the finite-n LUE or the JUE, satisfies the Jimbo–Miwa–Okamoto σ form of PV and PVI, although in the shift Jacobi case, with the weight xα(1−xβ, the β parameter does not show up in the equation. We also obtain the asymptotic expansions for the smallest eigenvalue distributions of the Laguerre unitary and Jacobi unitary ensembles after appropriate double scalings, and obtained the constants in the asymptotic expansion of the gap probabilities, expressed in term of the Barnes G-function valuated at special point.

  18. Low temperature magnetic structure of MnSe

    Indian Academy of Sciences (India)

    Abstract. In this paper we report low temperature neutron diffraction studies on MnSe in order to understand the anomalous behaviour of their magnetic and transport prop- erties. Our study indicates that at low temperatures MnSe has two coexisting crystal structures, high temperature NaCl and hexagonal NiAs. NiAs phase ...

  19. Low temperature thin films for next-generation microelectronics (invited)

    NARCIS (Netherlands)

    Schmitz, Jurriaan


    In this article the current methodologies for low-temperature thin film deposition in microelectronics are reviewed. The paper discusses the high temperature processes in microchip manufacturing and describes the thermal budget fitting issue. The quest for low temperature deposition techniques is

  20. Low temperature gaseous surface hardening of stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.


    The present contribution gives an overview of some of the technological aspects of low temperature thermochemical treatment of stainless steel. Examples of low temperature gaseous nitriding, carburising and nitrocarburising of stainless steel are presented and discussed. In particular......, the morphology, microstructure and characteristics of so-called expanite “layers” on stainless steel are addressed....

  1. Low temperature gaseous surface hardening of stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.


    The present contribtion gives an overview of some of the technological aspects of low temperature thermochemical treatment of stainless steel. Examples of low temperature gaseous nitriding, carburising and nitrocarburising of stainless steel are presented and discussed. In particular......, the morphology, microstructure and characteristics of so-called expanded austenite "layers" on stainless steel are addressed....

  2. Physiological and biochemical responses to low temperature stress ...

    African Journals Online (AJOL)

    Cuttings of three hybrid clones of P. ussuriensis × P. deltoides were exposed to different low temperatures (cold and freezing) for 24 h, or consecutive low temperatures (5°C, 0 to 120 h), to determine physiological and biochemical responses to cold stress in these woody plants. Soluble sugar and protein contents increased ...

  3. Endoscopic classification of representations of quasi-split unitary groups

    CERN Document Server

    Mok, Chung Pang


    In this paper the author establishes the endoscopic classification of tempered representations of quasi-split unitary groups over local fields, and the endoscopic classification of the discrete automorphic spectrum of quasi-split unitary groups over global number fields. The method is analogous to the work of Arthur on orthogonal and symplectic groups, based on the theory of endoscopy and the comparison of trace formulas on unitary groups and general linear groups.

  4. Quench of non-Markovian coherence in the deep sub-Ohmic spin–boson model: A unitary equilibration scheme

    International Nuclear Information System (INIS)

    Yao, Yao


    The deep sub-Ohmic spin–boson model shows a longstanding non-Markovian coherence at low temperature. Motivating to quench this robust coherence, the thermal effect is unitarily incorporated into the time evolution of the model, which is calculated by the adaptive time-dependent density matrix renormalization group algorithm combined with the orthogonal polynomials theory. Via introducing a unitary heating operator to the bosonic bath, the bath is heated up so that a majority portion of the bosonic excited states is occupied. It is found in this situation the coherence of the spin is quickly quenched even in the coherent regime, in which the non-Markovian feature dominates. With this finding we come up with a novel way to implement the unitary equilibration, the essential term of the eigenstate-thermalization hypothesis, through a short-time evolution of the model

  5. Magnetometer probe with low temperature rotation and optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Pajerowski, D M; Meisel, M W [Department of Physics and the National High Magnetic Field Laboratory, University of Florida, Gainesville, Florida 32611-8440 (United States)], E-mail:


    A new probe has been developed that allows for both optical irradiation and uniaxial rotation, all in the low temperature environment of a commercial superconducting quantum interference device (SQUID) magnetometer. As part of the design process, various materials were investigated and characterized for their low temperature structural and magnetic properties, including nylon, Vespel, Delrin, Spiderwire monofilament, and PowerPro braided microfilament. Using this information, a prototype was built and operated. Characteristics of the probe will be presented along with a summary of the low temperature (T {>=} 2 K) and high magnetic field (H {<=} 7 T) properties of the construction materials.

  6. Magnetometer probe with low temperature rotation and optical fibers (United States)

    Pajerowski, D. M.; Meisel, M. W.


    A new probe has been developed that allows for both optical irradiation and uniaxial rotation, all in the low temperature environment of a commercial superconducting quantum interference device (SQUID) magnetometer. As part of the design process, various materials were investigated and characterized for their low temperature structural and magnetic properties, including nylon, Vespel, Delrin, Spiderwire monofilament, and PowerPro braided microfilament. Using this information, a prototype was built and operated. Characteristics of the probe will be presented along with a summary of the low temperature (T >= 2 K) and high magnetic field (H <= 7 T) properties of the construction materials.

  7. Low-temperature phase transformation in rubidium and cesium superoxides

    International Nuclear Information System (INIS)

    Alikhanov, R.A.; Toshich, B.S.; Smirnov, L.S.


    Crystal structures of rubidium and cesium superoxides which are two interpenetrating lattices of metal ions and oxygen molecule ions reveal a number of phase transformations with temperature decrease. Crystal-phase transformations in CsO 2 are 1-2, 2-3 and low temperature one 3-4 at 378, 190 and 10 K. Low temperature transition is considered as the instability of lattice quadrupoles of oxygen molecule ions to phase transformation of the order-disorder type. Calculated temperatures of low temperature phase transformations in PbO 2 and CsO 2 agree with experimental calculations satisfactory [ru

  8. Low temperature safety of lithium-thionyl chloride cells (United States)

    Subbarao, S.; Deligiannis, F.; Shen, D. H.; Dawson, S.; Halpert, G.

    The use of lithium thionyl chloride cells for low-temperature applications is presently restricted because of their unsafe behavior. An attempt is made in the present investigation to identify the safe/unsafe low temperature operating conditions and to understand the low temperature cell chemistry responsible for the unsafe behavior. Cells subjected to extended reversal at low rate and -40 C were found to explode upon warm-up. Lithium was found to deposit on the carbon cathodes during reversal. Warming up to room temperature may be accelerating the lithium corrosion in the electrolyte. This may be one of the reasons for the cell thermal runaway.

  9. Perfect state transfer in unitary Cayley graphs over local rings

    Directory of Open Access Journals (Sweden)

    Yotsanan Meemark


    Full Text Available In this work, using eigenvalues and eigenvectors of unitary Cayley graphs over finite local rings and elementary linear algebra, we characterize which local rings allowing PST occurring in its unitary Cayley graph. Moreover, we have some developments when $R$ is a product of local rings.

  10. Unitary representations of the fundamental group of orbifolds

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 126; Issue 4. Unitary representations of the fundamental group of orbifolds. INDRANIL BISWAS AMIT HOGADI. Research Article Volume 126 Issue 4 October 2016 pp ... Keywords. Orbifolds; polystable vector bundle; fundamental group; unitary representation ...

  11. Micromachined Active Magnetic Regenerator for Low Temperature Magnetic Coolers Project (United States)

    National Aeronautics and Space Administration — NASA's future science missions to investigate the structure and evolution of the universe require highly efficient, very low temperature coolers for low noise...

  12. Research on roadway performance and distress at low temperature. (United States)


    This research project investigated the performance and damage characteristics of Nebraska roadways at low-temperature : conditions. To meet the research objective, laboratory tests were incorporated with mechanistic numerical modeling. The : three mo...

  13. Predicting low-temperature cracking in asphalt pavements : [research brief]. (United States)


    In Wisconsin's winter climate, low temperatures can cause asphalt pavements to contract and crack, reducing their ride quality and service lives. To help engineers more accurately determine how well certain pavement designs will fare in such conditio...

  14. SmallSat Low Mass, Extreme Low Temperature Energy Storage (United States)

    National Aeronautics and Space Administration — High specific energy, low-temperature power systems would allow space exploration missions to do more science over longer periods, farther from the sun. This...

  15. Physiological and molecular changes in plants grown at low temperatures. (United States)

    Theocharis, Andreas; Clément, Christophe; Barka, Essaïd Ait


    Apart from water availability, low temperature is the most important environmental factor limiting the productivity and geographical distribution of plants across the world. To cope with cold stress, plant species have evolved several physiological and molecular adaptations to maximize cold tolerance by adjusting their metabolism. The regulation of some gene products represents an additional mechanism of cold tolerance. A consequence of these mechanisms is that plants are able to survive exposure to low temperature via a process known as cold acclimation. In this review, we briefly summarize recent progress in research and hypotheses on how sensitive plants perceive cold. We also explore how this perception is translated into changes within plants following exposure to low temperatures. Particular emphasis is placed on physiological parameters as well as transcriptional, post-transcriptional and post-translational regulation of cold-induced gene products that occur after exposure to low temperatures, leading to cold acclimation.

  16. 2014 Low-Temperature and Coproduced Geothermal Resources Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Tim Reinhardt, Program Manager


    As a growing sector of geothermal energy development, the Low-Temperature Program supports innovative technologies that enable electricity production and cascaded uses from geothermal resources below 300° Fahrenheit.

  17. Low-Temperature Microbial Activity in River Systems

    National Research Council Canada - National Science Library

    White, K


    This technical note examines dissolved oxygen (DO) levels and changes in river microbiology during winter, low temperatures, and periods of ice cover with the objective of providing guidance for winter water quality modeling...

  18. Lightweight Superconducting Magnets for Low Temperature Magnetic Coolers, Phase II (United States)

    National Aeronautics and Space Administration — NASA's future science missions to investigate the structure and evolution of the universe require efficient, very low temperature coolers for low noise detector...

  19. Lightweight Superconducting Magnets for Low Temperature Magnetic Coolers Project (United States)

    National Aeronautics and Space Administration — NASA's future science missions to investigate the structure and evolution of the universe require efficient, very low temperature coolers for low noise detector...

  20. Highly Effective Thermal Regenerator for Low Temperature Cryocoolers, Phase I (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...

  1. Unitary Quantum Relativity. (Work in Progress) (United States)

    Finkelstein, David Ritz


    A quantum universe is expressed as a finite unitary relativistic quantum computer network. Its addresses are subject to quantum superposition as well as its memory. It has no exact mathematical model. It Its Hilbert space of input processes is also a Clifford algebra with a modular architecture of many ranks. A fundamental fermion is a quantum computer element whose quantum address belongs to the rank below. The least significant figures of its address define its spin and flavor. The most significant figures of it adress define its orbital variables. Gauging arises from the same quantification as space-time. This blurs star images only slightly, but perhaps measurably. General relativity is an approximation that splits nature into an emptiness with a high symmetry that is broken by a filling of lower symmetry. Action principles result from self-organization pf the vacuum.

  2. Research of the high performance low temperature vortex street flowmeter (United States)

    Gao, Feng; Chen, Yang; Zhang, Zhen-peng; Geng, Wei-guo


    Flow measurement is the key method for R&D and operation monitoring of liquid rocket engine. Therefore, it is important to measure flux of low temperature liquid propellants for the liquid hydrogen/liquid oxygen or the liquid oxygen/kerosene rocket engine. Presently in China, the level meter and the turbine flowmeter are usually used in the experimentation of the liquid hydrogen/liquid oxygen rocket engine. The level meter can only scale average flux and the precision of the turbine flowmeter (the measuring wild point is 1.5%) can not be ensured due to the reason which there is not devices of low temperature real-time demarcation in China. Therefore, it is required to research the high performance low temperature flow measurement equipment and the vortex street flowmeter is selected because of its advantages. In the paper, some key techniques of low temperature vortex street flowmeter are researched from the design aspect. Firstly, the basic theoretical research of vortex street flowmeter includes signal detection method, shape of vortex producer and effects of dimension of vertex producer to vortex quality. Secondly, low temperature vortex street flowmeter adopts the method of piezoelectric components stress mode. As for the weakness of phase-change, lattice change and fragility for many piezoelectric materials in low temperature, it can not be fulfilled piezoelectric signal and mechanism performance under this condition. Some piezoelectric materials which can be used in low temperature are illustrated in the paper by lots of research in order for the farther research. The article places emphasis upon low temperature trait of piezoelectric materials, and the structure designs of signal detector and calculation of stress, electric charge quantity and heat transfer.

  3. Measured Performance of a Low Temperature Air Source Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    R.K. Johnson


    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor “boosted heat pump” technology. The Low Temperature Heat Pump system operates with four increasing levels of capacity (heat output) as the outdoor temperature drops.


    African Journals Online (AJOL)

    The effect of a low temperature ageing treatment on the hardness, tensile and corrosion characteristics of sand cast Al-6.5%Si-0.35%Mg alloy was studied. The temper conditions are low temperature ageing at 90oC, 95oC, 100oCand 105oC respectively followed by ageing to 180oC for 2 hrs. This was compared with the ...

  5. Quantum simulation of low-temperature metallic liquid hydrogen


    Chen, Ji; Xin-Zheng, Li; Zhang, Qianfan; Probert, Matt; Pickard, Chris J.; Needs, Richard J.; Michaelides, Angelos; Wang, Enge


    Experiments and computer simulations have shown that the melt-ing temperature of solid hydrogen drops with pressure above about 65 GPa, suggesting that a liquid state might exist at low temperatures. It has also been suggested that this low temperature liquid state might be non-molecular and metallic, although evidence for such behaviour is lacking. Here, we report results for hydrogen at high pressures using ab initio path-integral molecular dynamics methods, which include a description of t...

  6. Innovative system for delivery of low temperature district heating


    Ianakiev, A; Cui, JM; Garbett, S; Filer, A


    An innovative low temperature district heating (LTDH) local network is developed in Nottingham, supported by the REMOURBAN project, part of the H2020 Smart City and Community Lighthouse scheme. It was proposed that a branch emanating from the return pipe of the existing district heating system in Nottingham would be created to use low temperature heating for the first time on such scale in the UK. The development is aimed to extract unused heat from existing district heating system and to mak...

  7. Spin Transport in a Unitary Fermi Gas (United States)

    Thywissen, Joseph


    We study spin transport in a quantum degenerate Fermi gas of 40K near an s-wave interaction resonance. The starting point of our measurements is a transversely spin-polarized gas, where each atom is in a superposition of the lowest two Zeeman eigenstates. In the presence of an external gradient, a spin texture develops across the cloud, which drives diffusive spin currents. Spin transport is described with two coefficients: D0⊥, the transverse spin diffusivity, and γ, the Leggett-Rice parameter. Diffusion is a dissipative effect that increases the entropy of the gas, eventually creating a mixture of spin states. γ parameterizes the rate at which spin current precesses around the local magnetization. Using a spin-echo sequence, we measure these transport parameters for a range of interaction strengths and temperatures. At unitarity, for a normal-state gas initially at one fifth of the Fermi temperature, we find D0⊥ = 2 . 3 (4) ℏ / m and γ = 1 . 08 (9) , where m is the atomic mass. In the limit of zero temperature, γ and D0⊥ are scale-invariant universal parameters of the unitary Fermi gas. The value of D0⊥ reveals strong scattering and is near its proposed quantum limit, such that the inferred value of the transport lifetime τ⊥ is comparable to ℏ /ɛF . This raises the possibility that incoherent transport may play a role. The nonzero value of γ tells us that spin waves in unitary Fermi gas are dispersive, or in other words, that the gas has a spin stiffness in the long-wavelength limit. Time permitting, we will also discuss a time-resolved measurement of the contact, through which we observe the microscopic transformation of the gas from ideal to strongly correlated.

  8. Quantum Entanglement Growth under Random Unitary Dynamics

    Directory of Open Access Journals (Sweden)

    Adam Nahum


    Full Text Available Characterizing how entanglement grows with time in a many-body system, for example, after a quantum quench, is a key problem in nonequilibrium quantum physics. We study this problem for the case of random unitary dynamics, representing either Hamiltonian evolution with time-dependent noise or evolution by a random quantum circuit. Our results reveal a universal structure behind noisy entanglement growth, and also provide simple new heuristics for the “entanglement tsunami” in Hamiltonian systems without noise. In 1D, we show that noise causes the entanglement entropy across a cut to grow according to the celebrated Kardar-Parisi-Zhang (KPZ equation. The mean entanglement grows linearly in time, while fluctuations grow like (time^{1/3} and are spatially correlated over a distance ∝(time^{2/3}. We derive KPZ universal behavior in three complementary ways, by mapping random entanglement growth to (i a stochastic model of a growing surface, (ii a “minimal cut” picture, reminiscent of the Ryu-Takayanagi formula in holography, and (iii a hydrodynamic problem involving the dynamical spreading of operators. We demonstrate KPZ universality in 1D numerically using simulations of random unitary circuits. Importantly, the leading-order time dependence of the entropy is deterministic even in the presence of noise, allowing us to propose a simple coarse grained minimal cut picture for the entanglement growth of generic Hamiltonians, even without noise, in arbitrary dimensionality. We clarify the meaning of the “velocity” of entanglement growth in the 1D entanglement tsunami. We show that in higher dimensions, noisy entanglement evolution maps to the well-studied problem of pinning of a membrane or domain wall by disorder.

  9. New developments in low temperature physics New developments in low temperature physics (United States)

    Hallock, Bob; Paalanenn, Mikko


    Below you will find part of the activity report to the IUPAP General Assembly, October 2008, by the present and previous Chairmen of C5. It provides an overview of the most important and recent developments in low temperature physics, much in line with the program of LT25. For the field of experimental low temperature physics, the ability to conduct research has been damaged by the dramatic increase in the price of liquid helium. In the USA, for example, the price of liquid helium has approximately doubled over the past two years. This has led to a reduction in activity in many laboratories as the funding agencies have not quickly increased support in proportion. The increase in price of liquid helium has accelerated interest in the development and use of alternative cooling systems. In particular, pulse-tube coolers are now available that will allow cryostats with modest cooling needs to operate dilution refrigerators without the need for repeated refills of liquid helium from external supply sources. Solid helium research has seen a dramatic resurgence. Torsional oscillator experiments have been interpreted to show that solid helium may undergo a transition to a state in which some of the atoms in the container do not follow the motion of the container, e.g. may be 'supersolid'. The observation is robust, but the interpretation is controversial. The shear modulus of solid helium undergoes a similar signature with respect to temperature. Experiments that should be expected to cause helium to flow give conflicting results. Theory predicts that a perfect solid cannot show supersolid behavior, but novel superfluid-like behavior should be seen in various defects that can exist in the solid, and vorticity may play a significant role. And, recently there have been reports of unusual mass decoupling in films of pure 4He on graphite surfaces as well as 3He- 4He mixture films on solid hydrogen surfaces. These may be other examples of unusual superfluid-like behavior. There

  10. Low temperature carbide precipitation in a nickel base superalloy (United States)

    Garosshen, T. J.; McCarthy, G. P.


    A M23C6 carbide phase has been observed to precipitate at relatively low temperatures (732 to 760 °C) in a nickel base superalloy.* Transmission Electron Microscopy shows the low temperature carbide to reside at the grain boundaries in a continuous morphology. The continuous carbide has a typical width of 25 to 40 nm with aspect ratios on the order of 30:1. The structure of the carbide is face-centered cubic with a lattice parameter (α0) of approximately 1.063 nm, which is typical of the M23C6 carbides that form at higher temperatures. STEM analysis indicates the carbide to have a typical M23C6 chemistry, enriched in chromium with lesser amounts of molybdenum, cobalt, and nickel. The formation of the continuous carbide occurs readily around 760 °C; however, at temperatures 55 °C lower the precipitation kinetics are significantly reduced. The extent of the low temperature carbide reaction is observed to be dependent upon the duration of the low temperature exposure and the degree of prior M23C6 stabilization at an intermediate temperature. Alloy modifications, involving hafnium additions and lower carbon levels, were studied with the aim of reducing the extent of this carbide reaction. Despite these chemistry modifications, the low temperature carbide was still observed to form to an appreciable extent. The presence of the continuous carbide is also observed to reduce the stress-rupture life of the alloy.

  11. Transcriptome profiling of sweetpotato tuberous roots during low temperature storage. (United States)

    Ji, Chang Yoon; Chung, Won-Hyong; Kim, Ho Soo; Jung, Won Yong; Kang, Le; Jeong, Jae Cheol; Kwak, Sang-Soo


    Sweetpotato [Ipomoea batatas (L.) Lam] is a globally important root crop with high industrial value. However, because sweetpotato tuberous roots undergo chilling injuries that negatively affect their quality at temperatures below 10 °C, postharvest damage during the winter season is a major constraint for industrialization. To understand chilling injury response during postharvest low temperature storage, we used next-generation sequencing technology to comprehensive analyze the transcriptome of tuberous roots stored at optimal (13 °C) or low temperature (4 °C) for 6 weeks. From nine cDNA libraries, we produced 298,765,564 clean reads, which were de novo assembled into 58,392 unigenes with an average length of 1100 bp. A total of 3216 differentially expressed genes (DEGs) were detected and categorized into six clusters, of which clusters 2, 4, and 5 (1464 DEGs) were up-regulated under low temperature. The genes in these three clusters are involved in biosynthesis of unsaturated fatty acids, pathogen defense, and phenylalanine metabolism. By contrast, genes in clusters 1, 3, and 6 (1752 DEGs), which were generally down-regulated at low temperature, encode antioxidant enzymes or are involved in glycerophospholipid, carbohydrate, or energy metabolism. We confirmed the results of the transcriptome analysis by quantitative RT-PCR. Our transcriptome analysis will advance our understanding of the comprehensive mechanisms of chilling injury during low temperature storage and facilitate improvements in postharvest storage of sweetpotato tuberous roots. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  12. Residential Waste

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Fruergaard, Thilde; Matsufuji, Y.


    are discussed in this chapter. Characterizing residential waste is faced with the problem that many residences already divert some waste away from the official collection systems, for example performing home composting of vegetable waste and garden waste, having their bundled newspaper picked up by the scouts...... twice a year or bringing their used furniture to the flea markets organized by charity clubs. Thus, much of the data available on residential waste represents collected waste and not necessarily all generated waste. The latter can only be characterized by careful studies directly at the source...

  13. Low Temperature Characterization of Ceramic and Film Power Capacitors (United States)

    Hammoud, Ahmad; Overton, Eric


    Among the key requirements for advanced electronic systems is the ability to withstand harsh environments while maintaining reliable and efficient operation. Exposures to low temperature as well as high temperature constitute such stresses. Applications where low temperatures are encountered include deep space missions, medical imaging equipment, and cryogenic instrumentation. Efforts were taken to design and develop power capacitors capable of wide temperature operation. In this work, ceramic and film power capacitors were developed and characterized as a function of temperature from 20 C to -185 C in terms of their dielectric properties. These properties included capacitance stability and dielectric loss in the frequency range of 50 Hz to 100 kHz. DC leakage current measurements were also performed on the capacitors. The manuscript presents the results that indicate good operational characteristic behavior and stability of the components tested at low temperatures.

  14. Low-temperature growth of nanostructured diamond films. (United States)

    Baker, P A; Catledge, S A; Vohra, Y K


    Nanostructured diamond films are grown on a titanium alloy substrate using a two-step deposition process. The first step is performed at elevated temperature (820 degrees C) for 30 min using a H2/CH4/N2 gas mixture to grow a thin (approximately 600 nm) nanostructured diamond layer and to improve film adhesion. The remainder of the deposition involves growth at low temperature (diamond film growth during low-temperature deposition is confirmed by in situ laser reflectance interferometry, atomic force microscopy, micro-Raman spectroscopy, and surface profilometry. Similar experiments performed without the initial nanostructured diamond layer resulted in poorly adhered films with a more crystalline appearance and a higher surface roughness. This low-temperature deposition of nanostructured diamond films on metals offers advantages in cases where high residual thermal stress leads to delamination at high temperatures.

  15. Asymptotic expansions for the Gaussian unitary ensemble

    DEFF Research Database (Denmark)

    Haagerup, Uffe; Thorbjørnsen, Steen


    Let g : R ¿ C be a C8-function with all derivatives bounded and let trn denote the normalized trace on the n × n matrices. In Ref. 3 Ercolani and McLaughlin established asymptotic expansions of the mean value ¿{trn(g(Xn))} for a rather general class of random matrices Xn, including the Gaussian U...... and covariance considered above correspond to, respectively, the one- and two-dimensional Cauchy (or Stieltjes) transform of the ....... Unitary Ensemble (GUE). Using an analytical approach, we provide in the present paper an alternative proof of this asymptotic expansion in the GUE case. Specifically we derive for a random matrix Xn that where k is an arbitrary positive integer. Considered as mappings of g, we determine the coefficients...... aj(g), j ¿ N, as distributions (in the sense of L. Schwarts). We derive a similar asymptotic expansion for the covariance Cov{Trn[f(Xn)], Trn[g(Xn)]}, where f is a function of the same kind as g, and Trn = n trn. Special focus is drawn to the case where and for ¿, µ in C\\R. In this case the mean...

  16. Nozzle dam having a unitary plug (United States)

    Veronesi, L.; Wepfer, R.M.


    Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator is disclosed. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening. Each plug includes a plurality of arms operable to engage the slots of the bracket for connecting each plug to the bracket, so that the nozzle is sealed as the plugs seal the openings and are connected to the bracket. 16 figs.

  17. Low Temperature District Heating for Future Energy Systems

    DEFF Research Database (Denmark)

    Ford, Rufus; Pietruschka, Dirk; Sipilä, Kari

    This report titled “Case studies and demonstrations” is the subtask D report of the IEA DHC|CHP Annex TS1 project “Low Temperature District Heating for Future Energy Systems” carried out between 2013 and 2016. The project was led by Fraunhofer Institute for Building Physics (IBP) with the other...... include examples on low temperature district heating systems, solar heating in a district heating system, heat pump based heat supply and energy storages for both peak load management and for seasonal heat storage. Some demonstrations have been implemented while others are at planning phase...

  18. Low temperature electrolytes for lithium/silver vanadium oxide cells (United States)

    Tuhovak, Denise R.; Takeuchi, Esther S.


    Combinations of methyl formate (MF) and propylene carbonate (PC) using salt concentrations of 0.6 to 2.4 M, with lithium hexafluoroarsenate and lithium tetrafluoroborate in a five to one molar ratio, were investigated as electrolytes in lithium/silver vanadium oxide batteries. The composition of the electrolyte affected cell performance at low temperature, self-discharge and abuse resistance as characterized by short circuit and crush testing. The electrolyte that provided the best combination of good low temperature performance, low cell self-discharge and abuse resistance was 0.6 M salt in 10:90 PC/MF.

  19. Heat Transfer and Cooling Techniques at Low Temperature

    CERN Document Server

    Baudouy, B


    The first part of this chapter gives an introduction to heat transfer and cooling techniques at low temperature. We review the fundamental laws of heat transfer (conduction, convection and radiation) and give useful data specific to cryogenic conditions (thermal contact resistance, total emissivity of materials and heat transfer correlation in forced or boiling flow for example) used in the design of cooling systems. In the second part, we review the main cooling techniques at low temperature, with or without cryogen, from the simplest ones (bath cooling) to the ones involving the use of cryocoolers without forgetting the cooling flow techniques.

  20. Instrument for Measuring Thermal Conductivity of Materials at Low Temperatures (United States)

    Fesmire, James; Sass, Jared; Johnson, Wesley


    With the advance of polymer and other non-metallic material sciences, whole new series of polymeric materials and composites are being created. These materials are being optimized for many different applications including cryogenic and low-temperature industrial processes. Engineers need these data to perform detailed system designs and enable new design possibilities for improved control, reliability, and efficiency in specific applications. One main area of interest is cryogenic structural elements and fluid handling components and other parts, films, and coatings for low-temperature application. An important thermal property of these new materials is the apparent thermal conductivity (k-value).

  1. Low Temperature Resistive Switching Behavior in a Manganite (United States)

    Salvo, Christopher; Lopez, Melinda; Tsui, Stephen


    The development of new nonvolatile memory devices remains an important field of consumer electronics. A possible candidate is bipolar resistive switching, a method by which the resistance of a material changes when a voltage is applied. Although there is a great deal of research on this topic, not much has been done at low temperatures. In this work, we compare the room temperature and low temperature behaviors of switching in a manganite thin film. The data indicates that the switching is suppressed upon cooling to cryogenic temperatures, and the presence of crystalline charge traps is tied to the physical mechanism.

  2. Constructing a unitary title regime for the European Patent System

    NARCIS (Netherlands)

    Rodriguez, V.F.


    The European Patent System without any unitary title allows Member States to retain institutional arrangements within their borders and to prevent any moves to delegate responsibility outside the national sphere. This intergovernmental patent regime suffers from fragmentation due to national

  3. Elegant Coercion and Iran: Beyond the Unitary Actor Model

    National Research Council Canada - National Science Library

    Moss, J. C


    .... At its core, then, coercion is about state decision-making. Most theories of coercion describe states as if they were unitary actors whose decision-making results from purely rational cost-benefit calculations...

  4. Theory of the unitary representations of compact groups

    International Nuclear Information System (INIS)

    Burzynski, A.; Burzynska, M.


    An introduction contains some basic notions used in group theory, Lie group, Lie algebras and unitary representations. Then we are dealing with compact groups. For these groups we show the problem of reduction of unitary representation of Wigner's projection operators, Clebsch-Gordan coefficients and Wigner-Eckart theorem. We show (this is a new approach) the representations reduction formalism by using superoperators in Hilbert-Schmidt space. (author)

  5. Future Housing Energy Efficiency Associated with the Auckland Unitary Plan


    Bin Su


    The draft Auckland Unitary Plan outlines the future land used for new housing and businesses with Auckland population growth over the next thirty years. According to Auckland Unitary Plan, over the next 30 years, the population of Auckland is projected to increase by one million, and up to 70% of total new dwellings occur within the existing urban area. Intensification will not only increase the number of median or higher density houses such as terrace house, apartment building, etc. within t...

  6. Low temperature current transport of Sn-GaAs contacts

    NARCIS (Netherlands)

    Heida, J; Wees, B.J. van; Bakker, Siemon; Klapwijk, T.M.; Alphenaar, B.W.


    We measure low temperature current transport properties of superconducting Sn contacts to p+-GaAs. For contacts alloyed at 450-degrees-C, the current-voltage characteristics show a strong dependence on alloying time. The critical temperature of Sn near the superconductor-semiconductor interface

  7. Chamber for uniaxial pressure application at low temperatures

    International Nuclear Information System (INIS)

    Grillo, M.L.N.; Carmo, L.C.S. do; Picon, A.P.


    A chamber for alignment of low temperature ferroelastic domains in crystals by the use of uniaxial stress was built. The system allows the use of EPR and optical techniques, as well as X-ray irradiation at temperatures as low as 77K. (Author) [pt

  8. Low temperature catalyst-assisted pyrolysis of polymer precursors to ...

    Indian Academy of Sciences (India)


    Nov 15, 2017 ... Low temperature catalyst-assisted pyrolysis of polymer precursors to carbon. RAMYA ARAGA, SURESH KALI and CHANDRA S SHARMA. ∗. Creative and Advanced Research Based On Nanomaterials (CARBON) Laboratory, Department of Chemical ...

  9. A Low Temperature Synthetic Route to Nanocrystalline TiN

    African Journals Online (AJOL)


    A simple chemical synthetic route has been developed to prepare nanocrystalline titanium nitride (TiN) in an autoclave, by the reaction of metallic Ti with NaNH2 at low temperature of 500–600 °C. The samples were characterized by X-ray powder diffraction, transmission electron microscopy, and X-ray photoelectron ...

  10. Microwave-assisted low temperature synthesis of sodium zirconium ...

    Indian Academy of Sciences (India)


    Abstract. Microwave-assisted procedure for low temperature solid state synthesis of sodium zirconium phosphate (NZP), a material with the potential for immobilization and disposal of high level nuclear waste, was developed. Three selected fission products, namely, Cesium, Strontium and Tellurium were introduced ...

  11. Low-temperature magnetic modification of sensitive biological materials

    Czech Academy of Sciences Publication Activity Database

    Pospišková, K.; Šafařík, Ivo


    Roč. 142, mar (2015), s. 184-188 ISSN 0167-577X R&D Projects: GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : magnetic iron oxides particles * microwave-assisted synthesis * low-temperature magnetic modification * immobilized enzymes Subject RIV: BO - Biophysics Impact factor: 2.437, year: 2015

  12. Microwave-assisted low temperature synthesis of sodium zirconium ...

    Indian Academy of Sciences (India)

    Microwave-assisted procedure for low temperature solid state synthesis of sodium zirconium phosphate (NZP), a material with the potential for immobilization and disposal of high level nuclear waste, was developed. Three selected fission products, namely, Cesium, Strontium and Tellurium were introduced (substituted) in ...

  13. Electron-dislocation interaction at low temperatures. Progress report

    International Nuclear Information System (INIS)


    The interaction of mobile dislocations with electrons in copper and copper alloys has shown that dislocation motion in copper, at low temperature, can be treated as an analog of an underdamped oscillator. We have also shown that the viscous drag on mobile dislocations in type II superconductors can be treated as an acoustic attenuation of an elastic wave

  14. New polymer electrolytes for low temperature fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Sundholm, F.; Elomaa, M.; Ennari, J.; Hietala, S.; Paronen, M. [Univ. of Helsinki (Finland). Lab. of Polymer Chemistry


    Proton conducting polymer membranes for demanding applications, such as low temperature fuel cells, have been synthesised and characterised. Pre-irradiation methods are used to introduce sulfonic acid groups, directly or using polystyrene grafting, in stable, preformed polymer films. The membranes produced in this work show promise for the development of cost-effective, highly conducting membranes. (orig.)

  15. Microstructural Characterization of Low Temperature Gas Nitrided Martensitic Stainless Steel

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.


    The present work presents microstructural investigations of the surface zone of low temperature gas nitrided precipitation hardening martensitic stainless steel AISI 630. Grazing incidence X-ray diffraction was applied to investigate the present phases after successive removal of very thin sections...

  16. Localized temperature stability of low temperature cofired ceramics (United States)

    Dai, Steven Xunhu


    The present invention is directed to low temperature cofired ceramic modules having localized temperature stability by incorporating temperature coefficient of resonant frequency compensating materials locally into a multilayer LTCC module. Chemical interactions can be minimized and physical compatibility between the compensating materials and the host LTCC dielectrics can be achieved. The invention enables embedded resonators with nearly temperature-independent resonance frequency.

  17. Strong anisotropy in the low temperature Compton profiles of ...

    Indian Academy of Sciences (India)

    Compton profiles of momentum distribution of conduction electrons in the orthorhombic phase of -Ga metal at low temperature are calculated in the band model for the three crystallographic directions (100), (010), and (001). Unlike the results at room temperature, previously reported by Lengeler, Lasser and Mair, the ...

  18. Advanced Low Temperature Thermoelectric Materials for Cryogenic Power Generation (United States)

    National Aeronautics and Space Administration — The current state of the art thermoelectric materials for low temperatures for the past 50 years have been alloys based upon Bi2Te3 with ZT of 1.2 at 300 K.  These...

  19. Oregon Low-Temperature-Resource Assessment Program. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Priest, G.R.; Black, G.L.; Woller, N.M.


    Numerous low-temperature hydrothermal systems are available for exploitation throughout the Cascades and eastern Oregon. All of these areas have heat flow significantly higher than crustal averages and many thermal aquifers. In northeastern Oregon, low temperature geothermal resources are controlled by regional stratigraphic aquifers of the Columbia River Basalt Group at shallow depths and possibly by faults at greater depths. In southeastern Oregon most hydrothermal systems are of higher temperature than those of northeastern Oregon and are controlled by high-angle fault zones and layered volcanic aquifers. The Cascades have very high heat flow but few large population centers. Direct use potential in the Cascades is therefore limited, except possibly in the cities of Oakridge and Ashland, where load may be great enough to stimulate development. Absence of large population centers also inhibits initial low temperature geothermal development in eastern Oregon. It may be that uses for the abundant low temperature geothermal resources of the state will have to be found which do not require large nearby population centers. One promising use is generation of electricity from freon-based biphase electrical generators. These generators will be installed on wells at Vale and Lakeview in the summer of 1982 to evaluate their potential use on geothermal waters with temperatures as low as 80/sup 0/C (176/sup 0/F).

  20. Circulator Integrated in Low Temperature Co-fired Ceramics Technology

    NARCIS (Netherlands)

    Dijk, R. van; Bent, G. van der; Ashari, M.; McKay, M.


    We present a demonstration of an integrated circulator for TR modules using low temperature co-fired ceramic (LTCC) technology. Two different circulators have been realised to be used in TR modules in two different frequency bands, C-and Ku-band. The circulator is a three-port junction microstrip

  1. Microwave-assisted low temperature synthesis of sodium zirconium

    Indian Academy of Sciences (India)

    Microwave-assisted procedure for low temperature solid state synthesis of sodium zirconium phosphate (NZP), a material with the potential for immobilization and disposal of high level nuclear waste, was developed. Three selected fission products, namely, Cesium, Strontium and Tellurium were introduced (substituted) in ...

  2. Low temperature CVD growth of ultrathin carbon films

    Directory of Open Access Journals (Sweden)

    Chao Yang


    Full Text Available We demonstrate the low temperature, large area growth of ultrathin carbon films by chemical vapor deposition under atmospheric pressure on various substrates. In particularly, uniform and continuous carbon films with the thickness of 2-5 nm were successfully grown at a temperature as low as 500 oC on copper foils, as well as glass substrates coated with a 100 nm thick copper layer. The characterizations revealed that the low-temperature-grown carbon films consist on few short, curved graphene layers and thin amorphous carbon films. Particularly, the low-temperature grown samples exhibited over 90% transmittance at a wavelength range of 400-750 nm and comparable sheet resistance in contrast with the 1000oC-grown one. This low-temperature growth method may offer a facile way to directly prepare visible ultrathin carbon films on various substrate surfaces that are compatible with temperatures (500-600oC used in several device processing technologies.

  3. Recent progress in low-temperature silicon detectors

    CERN Document Server

    Abreu, M; Berglund, P; Borchi, E; Borer, K; Bruzzi, M; Buontempo, S; Casagrande, L; Chapuy, S; Cindro, V; D'Ambrosio, N; De Masi, R; Devine, S R H; Dezillie, B; Dierlamm, A; Dimcovski, Zlatomir; Eremin, V; Esposito, A; Granata, V; Grigoriev, E; Grohmann, S; Härkönen, J; Hauler, F; Heijne, Erik H M; Heising, S; Hempel, O; Herzog, R; Janos, S; Jungermann, L; Konorov, I; Li, Z; Lourenço, Carlos; Rato-Mendes, P; Menichelli, D; Mikuz, M; Niinikoski, Tapio O; Pagano, S; Palmieri, V G; Paul, S; Pirollo, S; Pretzl, Klaus; Ruggiero, G; Shea, V O; Smith, K; Solano, B P; Sonderegger, Peter; Sousa, P; Tuominen, E; Verbitskaya, E; Watts, S; Wobst, E; Zavrtanik, M; Da Vià, C; de Boer, Wim


    The CERN RD39 Collaboration studies the possibility to extend the detector lifetime in a hostile radiation environment by operating them at low temperatures. The outstanding illustration is the Lazarus effect, which showed a broad operational temperature range around 130 K for neutron irradiated silicon detectors.

  4. Synthesis, structure and low temperature study of electric transport ...

    Indian Academy of Sciences (India)

    Synthesis, structure and low temperature study of electric transport and magnetic properties of GdSr2MnCrO7. Devinder ... Keywords. Chemical synthesis; X-ray diffraction; electrical properties; magnetic properties. Abstract. The layered perovskite oxide, GdSr2MnCrO7, has been prepared by the standard ceramic method.

  5. Low-temperature formation of silicon and silicon oxide structures

    NARCIS (Netherlands)

    Ishihara, R.; Trifunovic, M.; Van der Zwan, M.


    A method for low-temperature formation of a silicon/silicon-oxide structure on a substrate is described wherein the method comprises: forming a first (poly)silane layer over at least part of a substrate; transforming said first (poly)silane layer directly into a (crystalline) silicon layer by

  6. Potential market and characteristics of low-temperature reactors

    International Nuclear Information System (INIS)

    Lerouge, B.


    The low-temperature (100 to 200 deg C) heat market for industrial applications and district heating is very important. Two main studies have been developed: a swimming pool reactor delivering water at 110 deg C and a prestressed concrete vessel reactor delivering water at 200 deg C [fr

  7. Low-temperature localization in the transport properties of self ...

    Indian Academy of Sciences (India)

    Transport properties; scattering mechanisms; low temperature localization. 1. Introduction. The investigation on mixed-valent manganites with per- ovskite structure is on run for the last two decades. Specially, the studies on the hole doped manganites, La1−δAδMnO3. (A = divalent atom) still demands special attention ...

  8. Frugal Biotech Applications of Low-Temperature Plasma. (United States)

    Machala, Zdenko; Graves, David B


    Gas discharge low-temperature air plasma can be utilized for a variety of applications, including biomedical, at low cost. We term these applications 'frugal plasma' - an example of frugal innovation. We demonstrate how simple, robust, low-cost frugal plasma devices can be used to safely disinfect instruments, surfaces, and water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Phonon, magnon and electron contributions to low temperature ...

    Indian Academy of Sciences (India)

    Later on, following double-exchange mechanism the role of magnon is assessed towards spe- cific heat and found that at much low temperature, specific heat shows almost T3/2 dependence on the temperature. The present investigation ..... rate the electron–phonon coupling, electronic specific heat coefficient will take the ...

  10. Effects of low temperature and drought on the physiological and ...

    African Journals Online (AJOL)

    Water deficiency and low temperature are two important ecological factors which affect the distribution and cultivation of oil palm. To find out how oil palm adapts to the environmental conditions, the dynamics of a series of important physiological components derived from the leaves of potted oil palm seedlings under ...

  11. Scintillation of sapphire under particle excitation at low temperature

    International Nuclear Information System (INIS)

    Amare, J; Beltran, B; Cebrian, S; Coron, N; Dambier, G; GarcIa, E; Gomez, H; Irastorza, I G; Leblanc, J; Luzon, G; Marcillac, P de; Martinez, M; Morales, J; Ortiz de Solorzano, A; Pobes, C; Puimedon, J; Redon, T; RodrIguez, A; Ruz, J; Sarsa, M L; Torres, L; Villar, J A


    The scintillation properties of undoped sapphire at very low temperature have been studied in the framework of the ROSEBUD (Rare Objects SEarch with Bolometers UnDerground) Collaboration devoted to dark matter searches. We present an estimation of its light yield under gamma, alpha and neutron excitation

  12. Strong anisotropy in the low temperature Compton profiles of ...

    Indian Academy of Sciences (India)

    Abstract. Compton profiles of momentum distribution of conduction electrons in the orthorhom- bic phase of α-Ga metal at low temperature are calculated in the band model for the three crys- tallographic directions (100), (010), and (001). Unlike the results at room temperature, previously reported by Lengeler, Lasser and ...

  13. Scintillation of sapphire under particle excitation at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Amare, J [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Beltran, B [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Cebrian, S [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Coron, N [Institut d' Astrophysique Spatiale, Bat 121, 91405 Orsay, Paris (France); Dambier, G [Institut d' Astrophysique Spatiale, Bat 121, 91405 Orsay, Paris (France); GarcIa, E; Gomez, H [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Irastorza, I G [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Leblanc, J [Institut d' Astrophysique Spatiale, Bat 121, 91405 Orsay, Paris (France); Luzon, G [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Marcillac, P de [Institut d' Astrophysique Spatiale, Bat 121, 91405 Orsay, Paris (France); Martinez, M [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Morales, J [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Ortiz de Solorzano, A [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Pobes, C [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Puimedon, J [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Redon, T [Institut d' Astrophysique Spatiale, Bat 121, 91405 Orsay, Paris (France); RodrIguez, A [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Ruz, J [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Sarsa, M L [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Torres, L [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain); Villar, J A [Laboratorio de Fisica Nuclear, Universidad de Zaragoza, 50009 Zaragoza (Spain)


    The scintillation properties of undoped sapphire at very low temperature have been studied in the framework of the ROSEBUD (Rare Objects SEarch with Bolometers UnDerground) Collaboration devoted to dark matter searches. We present an estimation of its light yield under gamma, alpha and neutron excitation.

  14. Low-temperature enhancement of plasmonic performance in silver films

    Czech Academy of Sciences Publication Activity Database

    Jayanti, S.V.; Park, J.H.; Dejneka, Alexandr; Chvostová, Dagmar; McPeak, K.M.; Chen, X.; Oh, S.H.; Norris, D.J.


    Roč. 5, č. 5 (2015), 1147-1155 ISSN 2159-3930 R&D Projects: GA ČR(CZ) GA15-13853S Institutional support: RVO:68378271 Keywords : plasmonic performance * silver films * low temperature * spectroscopic ellipsometry Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.657, year: 2015

  15. Physiological and biochemical responses to low temperature stress ...

    African Journals Online (AJOL)

    ajl yemi


    Nov 9, 2011 ... temperatures (cold and freezing) for 24 h, or consecutive low temperatures (5°C, 0 to 120 h), to determine .... min (Aebi, 1984). CAT activity was calculated and expressed as nmol H2O2 mg-1 protein min-1. POD (EC activity was measured using a modification of the method described by Chance.

  16. Low-Temperature Synthesis Routes to Intermetallic Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Schaak, Raymond E


    Over the past few years, our group has gained expertise at developing low-temperature solution-based synthetic pathways to complex nanoscale solids, with particular emphasis on nanocrystalline intermetallic compounds. Our synthetic capabilities are providing tools to reproducibly generate intermetallic nanostructures with simultaneous control over crystal structure, composition, and morphology. This DOE-funded project aims to expand these capabilities to intermetallic superconductors. This could represent an important addition to the tools that are available for the synthesis and processing of intermetallic superconductors, which traditionally utilize high-temperature, high-pressure, thin film, or gas-phase vacuum deposition methods. Our current knowledge of intermetallic superconductors suggests that significant enhancements could result from the inherent benefits of low-temperature solution synthesis, e.g. metastable phase formation, control over nanoscale morphology to facilitate size-dependent property studies, robust and inexpensive processability, low-temperature annealing and consolidation, and impurity incorporation (for doping, stoichiometry control, flux pinning, and improving the critical fields). Our focus is on understanding the superconducting properties as a function of synthetic route, crystal structure, crystallite size, and morphology, and developing the synthetic tools necessary to accomplish this. This research program can currently be divided into two classes of superconducting materials: intermetallics (transition metal/post transition metal) and metal carbides/borides. Both involve the development and exploitation of low-temperature synthesis routes followed by detailed characterization of structures and properties, with the goal of understanding how the synthetic pathways influence key superconducting properties of selected target materials. Because of the low-temperature methods used to synthesize them and the nanocrystalline morphologies

  17. Analysis of Low-Temperature Utilization of Geothermal Resources

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Brian


    Full realization of the potential of what might be considered “low-grade” geothermal resources will require that we examine many more uses for the heat than traditional electricity generation. To demonstrate that geothermal energy truly has the potential to be a national energy source we will be designing, assessing, and evaluating innovative uses for geothermal-produced water such as hybrid biomass-geothermal cogeneration of electricity and district heating and efficiency improvements to the use of cellulosic biomass in addition to utilization of geothermal in district heating for community redevelopment projects. The objectives of this project were: 1) to perform a techno-economic analysis of the integration and utilization potential of low-temperature geothermal sources. Innovative uses of low-enthalpy geothermal water were designed and examined for their ability to offset fossil fuels and decrease CO2 emissions. 2) To perform process optimizations and economic analyses of processes that can utilize low-temperature geothermal fluids. These processes included electricity generation using biomass and district heating systems. 3) To scale up and generalize the results of three case study locations to develop a regionalized model of the utilization of low-temperature geothermal resources. A national-level, GIS-based, low-temperature geothermal resource supply model was developed and used to develop a series of national supply curves. We performed an in-depth analysis of the low-temperature geothermal resources that dominate the eastern half of the United States. The final products of this study include 17 publications, an updated version of the cost estimation software GEOPHIRES, and direct-use supply curves for low-temperature utilization of geothermal resources. The supply curves for direct use geothermal include utilization from known hydrothermal, undiscovered hydrothermal, and near-hydrothermal EGS resources and presented these results at the Stanford

  18. Experiments on Quantum Hall Topological Phases in Ultra Low Temperatures

    International Nuclear Information System (INIS)

    Du, Rui-Rui


    This project is to cool electrons in semiconductors to extremely low temperatures and to study new states of matter formed by low-dimensional electrons (or holes). At such low temperatures (and with an intense magnetic field), electronic behavior differs completely from ordinary ones observed at room temperatures or regular low temperature. Studies of electrons at such low temperatures would open the door for fundamental discoveries in condensed matter physics. Present studies have been focused on topological phases in the fractional quantum Hall effect in GaAs/AlGaAs semiconductor heterostructures, and the newly discovered (by this group) quantum spin Hall effect in InAs/GaSb materials. This project consists of the following components: 1) Development of efficient sample cooling techniques and electron thermometry: Our goal is to reach 1 mK electron temperature and reasonable determination of electron temperature; 2) Experiments at ultra-low temperatures: Our goal is to understand the energy scale of competing quantum phases, by measuring the temperature-dependence of transport features. Focus will be placed on such issues as the energy gap of the 5/2 state, and those of 12/5 (and possible 13/5); resistive signature of instability near 1/2 at ultra-low temperatures; 3) Measurement of the 5/2 gaps in the limit of small or large Zeeman energies: Our goal is to gain physics insight of 5/2 state at limiting experimental parameters, especially those properties concerning the spin polarization; 4) Experiments on tuning the electron-electron interaction in a screened quantum Hall system: Our goal is to gain understanding of the formation of paired fractional quantum Hall state as the interaction pseudo-potential is being modified by a nearby screening electron layer; 5) Experiments on the quantized helical edge states under a strong magnetic field and ultralow temperatures: our goal is to investigate both the bulk and edge states in a quantum spin Hall insulator under

  19. NATO Advanced Study Institute on Low Temperature Molecular Spectroscopy

    CERN Document Server


    Molecular spectroscopy has achieved rapid and significant progress in recent years, the low temperature techniques in particular having proved very useful for the study of reactive species, phase transitions, molecular clusters and crystals, superconductors and semiconductors, biochemical systems, astrophysical problems, etc. The widening range of applications has been accompanied by significant improvements in experimental methods, and low temperature molecular spectroscopy has been revealed as the best technique, in many cases, to establish the connection between experiment and theoretical calculations. This, in turn, has led to a rapidly increasing ability to predict molecular spectroscopic properties. The combination of an advanced tutorial standpoint with an emphasis on recent advances and new perspectives in both experimental and theoretical molecular spectroscopy contained in this book offers the reader insight into a wide range of techniques, particular emphasis being given to supersonic jet and matri...

  20. Low-temperature mobility measurements on CMOS devices

    International Nuclear Information System (INIS)

    Hairpetian, A.; Gitlin, D.; Viswanathan, C.R.


    The surface channel mobility of carriers in eta- and rho-MOS transistors fabricated in a CMOS process was accurately determined at low temperatures down to 5 Κ. The mobility was obtained by an accurate measurement of the inversion charge density using a split C-V technique and the conductance at low drain voltages. The split C-V technique was validated at all temperatures using a one-dimensional Poisson solver (MOSCAP), which was modified for low-temperature application. The mobility dependence on the perpendicular electric field for different substrate bias values appears to have different temperature dependence for eta- and rho-channel devices. The electron mobility increases with a decrease in temperature at all gate voltages. On the other hand, the hole mobility exhibits a different temperature behavior depending upon whether the gate voltage corresponds to strong inversion or is near threshold

  1. Characteristic of Low Temperature Carburized Austenitic Stainless Steel (United States)

    Istiroyah; Pamungkas, M. A.; Saroja, G.; Ghufron, M.; Juwono, A. M.


    Low temperature carburizing process has been carried out on austenitic stainless steel (ASS) type AISI 316L, that contain chromium in above 12 at%. Therefore, conventional heat treatment processes that are usually carried out at high temperatures are not applicable. The sensitization process due to chromium migration from the grain boundary will lead to stress corrosion crack and decrease the corrosion resistance of the steel. In this study, the carburizing process was carried out at low temperatures below 500 °C. Surface morphology and mechanical properties of carburized specimens were investigated using optical microscopy, non destructive profilometer, and Vicker microhardness. The surface roughness analysis show the carburising process improves the roughness of ASS surface. This improvement is due to the adsorption of carbon atoms on the surface of the specimen. Likewise, the hardness test results indicate the carburising process increases the hardness of ASS.

  2. Enhanced Corrosion Resistance of Stainless Steel Carburized at Low Temperature (United States)

    Martin, F. J.; Natishan, P. M.; Lemieux, E. J.; Newbauer, T. M.; Rayne, R. J.; Bayles, R. A.; Kahn, H.; Michal, G. M.; Ernst, F.; Heuer, A. H.


    The pitting corrosion resistance of surface-modified 316L austenitic stainless steel and N08367 (a “superaustenitic” stainless steel) were evaluated in 0.6 M NaCl solutions and compared to untreated samples of the same materials. The surface modification process used to treat the surfaces was a low-temperature carburization technology termed “low-temperature colossal supersaturation” (LTCSS). The process typically produces surface carbon concentrations of ~15 at. pct without the formation of carbides. The pitting potential of the LTCSS-treated 316L stainless steel in the NaCl solution substantially increased compared to untreated 316L stainless steel, while the pitting behavior of the LTCSS-treated N08367 was unchanged compared to the untreated alloy.

  3. Low Temperature District Heating for Future Energy Systems

    DEFF Research Database (Denmark)

    Schmidt, Dietrich; Kallert, Anna; Blesl, Markus


    of the building stock. Low temperature district heating (LTDH) can contribute significantly to a more efficient use of energy resources as well as better integration of renewable energy (e.g. geothermal or solar heat), and surplus heat (e.g. industrial waste heat) into the heating sector. LTDH offers prospects......The building sector is responsible for more than one third of the final energy consumption of societies and produces the largest amount of greenhouse gas emissions of all sectors. This is due to the utilisation of combustion processes of mainly fossil fuels to satisfy the heating demand...... for both the demand side (community building structure) and the supply side (network properties or energy sources). Especially in connection with buildings that demand only low temperatures for space heating. The utilisation of lower temperatures reduces losses in pipelines and can increase the overall...

  4. Low-temperature creep of austenitic stainless steels (United States)

    Reed, R. P.; Walsh, R. P.


    Plastic deformation under constant load (creep) in austenitic stainless steels has been measured at temperatures ranging from 4 K to room temperature. Low-temperature creep data taken from past and unreported austenitic stainless steel studies are analyzed and reviewed. Creep at cryogenic temperatures of common austenitic steels, such as AISI 304, 310 316, and nitrogen-strengthened steels, such as 304HN and 3116LN, are included. Analyses suggests that logarithmic creep (creep strain dependent on the log of test time) best describe austenitic stainless steel behavior in the secondary creep stage and that the slope of creep strain versus log time is dependent on the applied stress/yield strength ratio. The role of cold work, strain-induced martensitic transformations, and stacking fault energy on low-temperature creep behavior is discussed. The engineering significance of creep on cryogenic structures is discussed in terms of the total creep strain under constant load over their operational lifetime at allowable stress levels.

  5. Waste Home Appliance Disposal and Low Temperature Crushing Technology (United States)

    Hayashi, Masakatsu; Takamura, Yoshiyuki

    From the viewpoint of environmental preservation, considerable interest is being advanced by the recycling of industrial goods such as home appliances. In terms of waste home appliances, there is an urgent need for an improvement in recycling rates for waste, because four items (refrigerators, airconditioners, washing machines and televisions) were designated as primary specified goods under those laws that encourage the use of recycled materials. Under this situation, new merits are being discovered in low temperature crushing technology as an appropriate disposal technology for recycling activities. Here, crushing and separating technology for metal composites, and crushing and sorting technology for plastics will be introduced as examples of low temperature crushing technology developed for waste home appliances that achieves recycling rates of over 90% through recycle system for waste home appliances.

  6. On the Interpretation of Low Temperature Calorimetry Data

    DEFF Research Database (Denmark)

    Kjeldsen, Ane Mette; Geiker, Mette Rica


    The effect of selected factors and phenomena on Low Temperature Calorimetry (LTC) results has been investigated, in order to determine the possibilities and limitations of using LTC for characterisation of the porosity of cement-based materials. LTC was carried out on a model material with mono......-sized pores of approximately 14 nm saturated with either distilled water or a sodium chloride solution, as well as on water, the salt solution, and an artificial pore solution, alone. It was found that supercooling is unavoidable during the liquid-solid phase transition, and that even at low temperature...... to limit transport of liquid, whereas heating should be undertaken at a low rate to limit the effect of non-equilibrium....

  7. Attenuation of low-temperature stress in rice seedlings

    Directory of Open Access Journals (Sweden)

    Mara Grohs


    Full Text Available Rice is a cold-sensitive crop, and its exposure to low-temperature stress, during germination and early seedling growth, can negatively affect the initial stand establishment. Substances that act as growth regulators can be used to mitigate this initial stress. Thus, the influence of gibberellic acid, thiamethoxam and a phytohormone was investigated at the growth variables and antioxidant enzyme activity of the 'Irga 424' and 'Puita Inta CL' rice cultivars, at low-temperature (17 ºC. The products act on the germination percentage of 'Puita Inta CL', but vigor is only influenced by giberellic acid. Giberellic acid influences shoot length, irrespective of cultivar, while thiamethoxam and the phytohormone only affect length in 'Puita Inta CL'. The antioxidant activity depends on the cultivar and organ tested (shoot or root. These products mitigate the effects of cold, thereby preventing the formation of reactive-oxygen species and lipid peroxidation, and positively influence the superoxide dismutase enzyme activity.

  8. Thermoelectric harvesting of low temperature natural/waste heat (United States)

    Rowe, David Michael


    Apart from specialized space requirements current development in applications of thermoelectric generation mainly relate to reducing harmful carbon emissions and decreasing costly fuel consumption through the recovery of exhaust heat from fossil fuel powered engines and emissions from industrial utilities. Focus on these applications is to the detriment of the wider exploitations of thermoelectrics with other sources of heat energy, and in particular natural occurring and waste low temperature heat, receiving little, if any, attention. In this presentation thermoelectric generation applications, both potential and real in harvesting low temperature waste/natural heat are reviewed. The use of thermoelectrics to harvest solar energy, ocean thermal energy, geothermal heat and waste heat are discussed and their credibility as future large-scale sources of electrical power assessed.

  9. Low Temperature Heating and High Temperature Cooling in Buildings

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk

    , a holistic system evaluation is necessary to ensure an optimal indoor environment for the occupants and to achieve energy efficiency simultaneously. Low temperature heating and high temperature cooling systems are one of the possible approaches to heat or cool indoor spaces in buildings. In this thesis...... were monitored for one year while different control strategies were tested. Theoretical analyses consisted of comparing the performance of different heating and cooling systems using energy, exergy, and entransy methods under steady-state conditions. Dynamic simulations were used to study the energy...... performance of heating and cooling systems for achieving the same thermal indoor environment. The results show that it is crucial to minimize the heating and cooling demands in the design phase since these demands determine the terminal units and heat sources and sinks that could be used. Low temperature...

  10. Thermal fluids in low temperature systems. Part 2

    Energy Technology Data Exchange (ETDEWEB)

    Lynde, P.G.; Yonkers, E.D. [Albert Kahn Associates, Inc., Detroit, MI (United States)


    This article focuses on the lifeblood of these systems, the thermal transfer fluid itself. Low-temperature heat-transfer fluids are used to condition engine fluids, test chambers, cooling fluids, or a combination of these in environmental test facilities. To meet the specific test criteria, these fluids may be required to maintain pumpability and function with thermal efficiency at temperatures as low as {minus}120 F. This article presents information related to heat-transfer fluids used in low-temperature cooling applications. Three general groups of fluids are discussed: water-based antifreezes (ethylene and propylene glycol solutions); chlorinated solvents (methylene chloride and trichloroethylene); organic and synthetic coolants (diethylbenzene, two forms of dimethylpolysiloxane, heavy naphtha hydrotreated, and citrus terpene).

  11. Study on low temperature plasma driven permeation of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Takizawa, Masayuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment


    It is one of the most important problem in PWI of fusion devices from the point of view of tritium leakage that hydrogen diffuses in the wall of the device and permeates through it, which results in hydrogen being released to the coolant side. In this study, plasma driven permeation experiments were carried out with several kinds of metal membranes in the low temperature plasma where ionic and atomic hydrogen as well as electron existed in order to survey PDP mechanism from the many view points. In addition, incident flux rate from the plasma to the membrane surface was evaluated by calculation analysis. As a result the mechanism of low temperature PDP was found out and described as PDP models. The simulation of the membrane pump system was executed and the system performance was estimated with the models. (author). 135 refs.

  12. Innovative system for delivery of low temperature district heating

    Directory of Open Access Journals (Sweden)

    Anton Ivanov Ianakiev


    Full Text Available An innovative Low Temperature District Heating (LTDH local network is developed in Nottingham, supported by REMOURBAN project, part of the H2020 Smart City and Community Lighthouse scheme. It was proposed that a branch emanating from the return pipe of the of the existing district heating system in Nottingham would be created to use low temperature heating for the first time in UK. The development is aimed to extract wasted (unused heat from existing district heating system and make it more efficient and profitable. Four maisonette blocks of 94 low-raised flats, at Nottingham demo site of the REMOURBAN project will be connected to this new LTDH system. The scheme will provide a primary supply of heat and hot water at approximately 50oC to 60oC. Innovated solutions have been put forward to overcome certain barriers, such as legionella related risks and peak loads during extreme heating seasons and occasional maintenance.

  13. Performance Limits and Opportunities for Low Temperature Thermal Desalination


    Nayar, Kishor Govind; Swaminathan, Jaichander; Warsinger, David Elan Martin; Lienhard, John H.


    Conventional low temperature thermal desalination (LTTD) uses ocean thermal temperature gradients to drive a single stage flash distillation process to produce pure water from seawater. While the temperature difference in the ocean drives distillation and provides cooling in LTTD, external electrical energy is required to pump the water streams from the ocean and to maintain a near vacuum in the flash chamber. In this work, an LTTD process from the literature is compared against, the thermody...

  14. Carbon fiber production at low temperatures from polyacrylonitrile (United States)

    Cagliostro, D. E.


    Recent safety considerations have sought to lower the electrical conductivity of carbon fibers. Carbon fibers produced from polyacrylonitrile at low carbonization temperatures (600-900 C) possess low electrical conductivity but do not possess adequate strength. Low-temperature processes are described which improve fiber strength but do not increase electrical conductivity substantially. The processes result in a carbon fiber with nearly twice the tensile strength compared to the old process. Process development and its effect on fiber properties are reported.

  15. Study of Plant Waxes Using Low Temperature Method for ESEM

    Czech Academy of Sciences Publication Activity Database

    Neděla, Vilém; Tihlaříková, Eva; Schiebertová, P.; Zajícová, I.; Schwarzerová, K.


    Roč. 22, S3 (2016), s. 1180-1181 ISSN 1431-9276 R&D Projects: GA ČR(CZ) GA14-22777S; GA MŠk ED0017/01/01 Grant - others:GA MŠk(CZ) LO1211 Institutional support: RVO:68081731 Keywords : ESEM * plant waxes * low temperature method Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.891, year: 2016

  16. Structural disorder and electron transport in graphene at low temperatures (United States)

    Bobenko, N. G.; Egorushkin, V. E.; Melnikova, N. V.; Ponomarev, A. N.; Belosludtseva, A. A.; Barkalov, L. D.


    A theoretical study of electron transport characteristics of metalized epitaxial graphene with impurities and structural inhomogeneous of the short-range order type was performed. The electron relaxation time, mean free path, and diffusion coefficient were calculated and shown to be of the same order of magnitude as the corresponding values for phonon characteristics. It means that electron scattering on the short-range ordered domains has to be taken into account, especially at low temperatures when it may dominate phonon scattering.

  17. Low temperature chemical processing of graphite-clad nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, Robert A.


    A reduced-temperature method for treatment of a fuel element is described. The method includes molten salt treatment of a fuel element with a nitrate salt. The nitrate salt can oxidize the outer graphite matrix of a fuel element. The method can also include reduced temperature degradation of the carbide layer of a fuel element and low temperature solubilization of the fuel in a kernel of a fuel element.

  18. Muon-catalyzed processes in dense low-temperature plasma

    International Nuclear Information System (INIS)

    Men'shikov, L.I.


    The processes of mesic atomic and mesic molecular formation in low-temperature plasma are discussed. The new effective muon shaking mechanism from dμ-ions by ''running away'' electrons is proposed. The principal possibility of considerable increasing the number of cycles of muon catalysis in deuterium-tritium mixture up to (0.5-1)x10 3 is shown. The conditions for effective muon catalysis in pure deuterium and in inhomogeneous plasma are pointed out

  19. Technological aspects of UO2 sintering at low temperature

    International Nuclear Information System (INIS)

    Thern, Gerardo G.; Dominguez, Carlos A.; Benitez, Ana M.; Marajofsky, Adolfo


    Within the Fuel Cycle Program of CNEA, the knowledge that plant personnel has on sintering at low temperature was evaluated, because this process could decrease costs for UO 2 and (U,Gd)O 2 pellets production, simplify the furnace maintenance and facilitate the automation of the production process, specially convenient for uranium recovery. By applying this technology, some companies have achieved production at pilot-scale and irradiated a significant number of pellets. (author)

  20. Low-temperature strain gauges based on silicon whiskers

    Directory of Open Access Journals (Sweden)

    Druzhinin A. A.


    Full Text Available To create low-temperature strain gauges based on p-type silicon whiskers tensoresistive characteristics of these crystals in 4,2—300 K temperature range were studied. On the basis of p-type Si whiskers with different resistivity the strain gauges for different materials operating at cryogenic temperatures with extremely high gauge factor at 4,2 K were developed, as well as strain gauges operating at liquid helium temperatures in high magnetic fields.

  1. Specific heat of actinide compounds at low temperature

    International Nuclear Information System (INIS)

    Novion, C. de.


    Actinide compounds show phenomena of self-heating and recovery of self-irradiation induced defects which imply the development of apparatus and special methods for the measurement of their specific heat at low temperature. The case of insulating or semiconductor compounds is considered, with emphasis on the oxides MO 2 . The problem of 5f electrons in metallic compounds, then pure metals and the self-irradiation problems are examined [fr

  2. Low-temperature behavior of the quark-meson model (United States)

    Tripolt, Ralf-Arno; Schaefer, Bernd-Jochen; von Smekal, Lorenz; Wambach, Jochen


    We revisit the phase diagram of strong-interaction matter for the two-flavor quark-meson model using the functional renormalization group. In contrast to standard mean-field calculations, an unusual phase structure is encountered at low temperatures and large quark chemical potentials. In particular, we identify a regime where the pressure decreases with increasing temperature and discuss possible reasons for this unphysical behavior.

  3. National Low-Temperature Neutron-Irradiation Facility

    International Nuclear Information System (INIS)

    Coltman, R.R. Jr.; Klabunde, C.E.; Young, F.W. Jr.


    The Materials Sciences Division of the United States Department of Energy will establish a National Low Temperature Neutron Irradiation Facility (NLTNIF) which will utilize the Bulk Shielding Reactor (BSR) located at Oak Ridge National Laboratory. The facility will provide high radiation intensities and special environmental and testing conditions for qualified experiments at no cost to users. This report describes the planned experimental capabilities of the new facility

  4. Low-temperature localization in the transport properties of self ...

    Indian Academy of Sciences (India)

    293–298. c Indian Academy of Sciences. Low-temperature localization in the transport properties of self-doped. La0.9Mn0.98Zn0.02O3. K DE1 and S DAS2,∗. 1Neotia Institute of Technology, Management and Science, Jhinga 743 368, India. 2Department of Electronics and Communication Engineering, Guru Ghasidas ...

  5. Internal frictions of austenitic stainless steels at low temperature (United States)

    Tsubono, K.; Owa, S.; Mio, N.; Akasaka, N.; Hirakawa, H.

    Internal frictions were measured for three types of austenitic stainless steel, AISI 304, 310S and 316, in the temperature range 4-300 K. The intrinsic friction is presented in terms of the quality factor of a 20 kHz eigenmode vibration of discs made from each material. Temperature dependence is also given for the resonant frequency of each disc. These mechanical properties show some peculiarities at low temperature.

  6. Coulometric titration at low temperatures-nonstoichiometric silver selenide


    Beck, Gesa K.; Janek, Jürgen


    A modified coulometric titration technique is described for the investigation of nonstoichiometric phases at low temperatures. It allows to obtain titration curves at temperatures where the conventional coulometric titration technique fails because of too small chemical diffusion coefficients of the mobile component. This method for indirect coulometric titration is applied to silver selenide between -100 and 100 °C. The titration curves are analyzed on the basis of a defect chemical model an...

  7. An assessment of high and low temperature tars in Psoriasis. (United States)

    Chapman, R S; Finn, O A


    Comparison of the efficacy of crude coal tar from high and low temperature sources in the treatment of patients suffering from chronic psoriasis showed the tars to be equally effective. High temperature tar was then compared with standard refined tar. Again, an equal therapeutic response was achieved. Crude coal tars obtained by the carbonization of coal in coke ovens and in smokeless fuel manufacture can be employed in dermatological therapy in place of the dwindling supplies of crude tar of gasworks origin.

  8. Low temperature phase transition in KOH and KOD

    International Nuclear Information System (INIS)

    Bastow, T.J.; Elcombe, M.M.; Howard, C.J.


    Dielectric constant and differential scanning calorimetry measurements have shown a transition to a new phase in both KOH (at 233 K) and KOD (at 257 K); the shape of the dielectric anomaly suggests electrical ordering at low temperature. Structural parameters obtained from high resolution neutron powder diffraction data demonstrate the ordering to be antiferroelectric. A preliminary account is given of the structures at 293 K and 77 K. (author)

  9. Low-temperature field evaporation of Nb3Sn compound

    International Nuclear Information System (INIS)

    Ksenofontov, V.A.; Kul'ko, V.B.; Kutsenko, P.A.


    Investigation results on field evaporation of superconducting Nb 3 Sn compound wth A15 lattice are presented. Compound evaporation is shown to proceed in two stages. Evaporation field and ionic composition of evaporating material are determined. It is found out that in strong electric fields compound surface represents niobium skeleton, wich does not form regular image. Comparison of ion-microscopic and calculated images formed by low-temperature field evaporation indicates to possibility of sample surface reconstruction after preferable tin evaporation

  10. Characterization of the National Low-Temperature Neutron Irradiation Facility

    Energy Technology Data Exchange (ETDEWEB)

    Kerchner, H.R.; Coltman, R.R. Jr.; Klabunde, C.E.; Young, F.W. Jr.


    The National Low-Temperature Neutron Irradiation Facility (NLTNIF) is now operating at the Bulk Shielding Reactor at ORNL. The facility provides high radiation intensities and special environmental and testing conditions for qualified experiments at no cost to users. A general description and major specifications of the NLTNIF are presented along with the results of performance tests. In addition, the hardware and other considerations required to perform experiments in the NLTNIF are described.

  11. Low-Temperature Co-Fired Unipoled Multilayer Piezoelectric Transformers. (United States)

    Gao, Xiangyu; Yan, Yongke; Carazo, Alfredo Vazquez; Dong, Shuxiang; Priya, Shashank


    The reliability of piezoelectric transformers (PTs) is dependent upon the quality of fabrication technique as any heterogeneity, prestress, or misalignment can lead to spurious response. In this paper, unipoled multilayer PTs were investigated focusing on high-power composition and co-firing profile in order to provide low-temperature synthesized high-quality device measured in terms of efficiency and power density. The addition of 0.2 wt% CuO into Pb 0.98 Sr 0.02 (Mg 1/3 Nb 2/3 ) 0.06 (Mn 1/3 Nb 2/3 ) 0.06 (Zr 0.48 Ti 0.52 ) 0.88 O 3 (PMMnN-PZT) reduces the co-firing temperature from 1240 °C to 930 °C, which allows the use of Ag/Pd inner electrode instead of noble Pt inner electrode. Low-temperature synthesized material was found to exhibit excellent piezoelectric properties ( , , %, pC/N, and °C). The performance of the PT co-fired with Ag/Pd electrode at 930 °C was similar to that co-fired at 1240 °C with Pt electrode (25% reduction in sintering temperature). Both high- and low-temperature synthesized PTs demonstrated 5-W output power with >90% efficiency and 11.5 W/cm 3 power density.

  12. Sucrose Phosphate Synthase and Sucrose Accumulation at Low Temperature 1 (United States)

    Guy, Charles L.; Huber, Joan L. A.; Huber, Steven C.


    The influence of growth temperature on the free sugar and sucrose phosphate synthase content and activity of spinach (Spinacia oleracea) leaf tissue was studied. When plants were grown at 25°C for 3 weeks and then transferred to a constant 5°C, sucrose, glucose, and fructose accumulated to high levels during a 14-d period. Predawn sugar levels increased from 14- to 20-fold over the levels present at the outset of the low-temperature treatment. Sucrose was the most abundant free sugar before, during, and after exposure to 5°C. Leaf sucrose phosphate synthase activity was significantly increased by the low-temperature treatment, whereas sucrose synthase and invertases were not. Synthesis of the sucrose phosphate synthase subunit was increased during and after low-temperature exposure and paralleled an increase in the steady-state level of the subunit. The increases in sucrose and its primary biosynthetic enzyme, sucrose phosphate synthase, are discussed in relation to adjustment of metabolism to low nonfreezing temperature and freezing stress tolerance. Images Figure 1 Figure 2 Figure 3 PMID:16652990

  13. Future directions in geobiology and low-temperature geochemistry (United States)

    Freeman, Katherine H.; Goldhaber, M.B.


    Humanity is confronted with an enormous challenge, as succinctly stated by the late Steven Schneider (2001; quoted by Jantzen 2004*): “Humans are forcing the Earth’s environmental systems to change at a rate that is more advanced than their knowledge of the consequences.” Geobiologists and low-temperature geochemists characterize material from the lithosphere, hydrosphere, atmosphere, and biosphere to understand processes operating within and between these components of the Earth system from the atomic to the planetary scale. For this reason, the interwoven disciplines of geobiology and low-temperature geochemistry are central to understanding and ultimately predicting the behavior of these life-sustaining systems. We present here comments and recommendations from the participants of a workshop entitled “Future Directions in Geobiology and Low-Temperature Geochemistry,” hosted by the Carnegie Institution of Washington, Geophysical Laboratory, Washington, DC, on 27–28 August 2010. The goal of the workshop was to suggest ways to leverage the vast intellectual and analytical capabilities of our diverse scientific community to characterize the Earth’s past, present, and future geochemical habitat as we enter the second decade of what E. O. Wilson dubbed “the century of the environment.”

  14. Low temperature discharge characteristics of lithium-manganese dioxide cells

    Energy Technology Data Exchange (ETDEWEB)

    Hampartzumian, K.; Iltchev, N.


    Lithium-manganese dioxide cells have not only excellent specific energy and shelf life characteristics, but they are also capable of very promising performance at temperatures as low as -40/sup 0/C (-40/sup 0/F). The polarization and discharge curves of cylindrical and button cells at -40/sup 0/C are compared in an effort to evaluate the useful low temperature operation range. The cathode design, and type of MnO/sub 2/ strongly affect the low temperature behaviour. Although the excellent low temperature performance of the Li/SO/sub 2/ system can probably never be equalled, due to some diffusion shortcomings inherent in the Li/MnO/sub 2/ cells, for low and moderate current drains covering many meteorological, military, and consumer applications, Li/MnO/sub 2/ batteries are very competitive in terms of simple technology, increased safety, and price, offering satisfactory operation within the range -40 to +71/sup 0/C (-40/sup 0/F to +160/sup 0/F).

  15. Electron microscopic observation at low temperature on superconductors

    International Nuclear Information System (INIS)

    Yokota, Yasuhiro; Hashimoto, Hatsujiro; Yoshida, Hiroyuki.


    The authors have observed superconducting materials with a high resolution electron microscope at liquid helium temperature. First, observation was carried out on Nb system intermetallic compounds such as Nb 3 Al and Nb 3 Sn of Al 5 type and Nb 3 Ge of 11 type at extremely low temperature. Next, the observation of high temperature superconductive ceramics in the state of superconductivity was attempted. In this paper, first the development of the liquid helium sample holder for a 400 kV electron microscope to realize the observation is reported. Besides, the sample holder of Gatan Co. and an extremely low temperature, high resolution electron microscope with a superconducting lens are described. The purpose of carrying out the electron microscope observation of superconductors at low temperature is the direct observation of the crystalline lattice image in the state of superconductivity. Also the structural transformation from tetragonal crystals to rhombic crystals in Al 5 type superconductors can be observed. The results of observation are reported. (K.I.)

  16. RNA silencing is resistant to low-temperature in grapevine.

    Directory of Open Access Journals (Sweden)

    Marjorie Romon

    Full Text Available RNA silencing is a natural defence mechanism against viruses in plants, and transgenes expressing viral RNA-derived sequences were previously shown to confer silencing-based enhanced resistance against the cognate virus in several species. However, RNA silencing was shown to dysfunction at low temperatures in several species, questioning the relevance of this strategy in perennial plants such as grapevines, which are often exposed to low temperatures during the winter season. Here, we show that inverted-repeat (IR constructs trigger a highly efficient silencing reaction in all somatic tissues in grapevines. Similarly to other plant species, IR-derived siRNAs trigger production of secondary transitive siRNAs. However, and in sharp contrast to other species tested to date where RNA silencing is hindered at low temperature, this process remained active in grapevine cultivated at 4°C. Consistently, siRNA levels remained steady in grapevines cultivated between 26°C and 4°C, whereas they are severely decreased in Arabidopsis grown at 15°C and almost undetectable at 4°C. Altogether, these results demonstrate that RNA silencing operates in grapevine in a conserved manner but is resistant to far lower temperatures than ever described in other species.

  17. The 2017 Plasma Roadmap: Low temperature plasma science and technology (United States)

    Adamovich, I.; Baalrud, S. D.; Bogaerts, A.; Bruggeman, P. J.; Cappelli, M.; Colombo, V.; Czarnetzki, U.; Ebert, U.; Eden, J. G.; Favia, P.; Graves, D. B.; Hamaguchi, S.; Hieftje, G.; Hori, M.; Kaganovich, I. D.; Kortshagen, U.; Kushner, M. J.; Mason, N. J.; Mazouffre, S.; Mededovic Thagard, S.; Metelmann, H.-R.; Mizuno, A.; Moreau, E.; Murphy, A. B.; Niemira, B. A.; Oehrlein, G. S.; Petrovic, Z. Lj; Pitchford, L. C.; Pu, Y.-K.; Rauf, S.; Sakai, O.; Samukawa, S.; Starikovskaia, S.; Tennyson, J.; Terashima, K.; Turner, M. M.; van de Sanden, M. C. M.; Vardelle, A.


    Journal of Physics D: Applied Physics published the first Plasma Roadmap in 2012 consisting of the individual perspectives of 16 leading experts in the various sub-fields of low temperature plasma science and technology. The 2017 Plasma Roadmap is the first update of a planned series of periodic updates of the Plasma Roadmap. The continuously growing interdisciplinary nature of the low temperature plasma field and its equally broad range of applications are making it increasingly difficult to identify major challenges that encompass all of the many sub-fields and applications. This intellectual diversity is ultimately a strength of the field. The current state of the art for the 19 sub-fields addressed in this roadmap demonstrates the enviable track record of the low temperature plasma field in the development of plasmas as an enabling technology for a vast range of technologies that underpin our modern society. At the same time, the many important scientific and technological challenges shared in this roadmap show that the path forward is not only scientifically rich but has the potential to make wide and far reaching contributions to many societal challenges.

  18. Auburn low-temperature geothermal well. Volume 6. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, R.S.; Castor, T.P.


    The Auburn well was drilled to explore for low temperature geothermal resources in central New York State. The Auburn site was selected based on: its proximity to the Cayuga County anomaly (30/sup 0/C/km), its favorable local geological conditions and the potential to provide hot water and space heating to two educational facilities. The well was drilled to a total depth of 5250 feet and into the Pre-Cambrian Basement. The well was extensively logged, flow and stress tested, hydraulically stimulated, and pump (pressure transient analysis) tested. The low-temperature geothermal potential was assessed in terms of: geological environment; hydrological conditions; reservoir characteristics; and recoverable hydrothermal reserves. The average geothermal gradient was measured to be as high as 26.7/sup 0/C/km with a bottom-hole temperature of 126/sup 0/ +- 1/sup 0/F. The proved volumetric resources were estimated to be 3.0 x 10/sup 6/ stock tank barrels (STB) with a maximum initial deliverability of approx.11,600 STB/D and a continuous deliverability of approx.3400 STB/D. The proved hydrothermal reserves were estimated to be 21.58 x 10/sup 10/ Btu based on a volumetric component (4.13 x 10/sup 10/ Btu), and a reinjection component (17.45 x 10/sup 10/ Btu). The conclusion was made that the Auburn low-temperature reservoir could be utilized to provide hot water and space heating to the Auburn School District.

  19. 12th International Workshop on Low Temperature Electronics

    International Nuclear Information System (INIS)


    The present volume of the Journal of Physics: Conference Series represents contributions from participants of the 12th International Workshop on Low Temperature Electronics held in Tempe, Arizona, USA from September 18-21, 2016. The conference was organized by the School of Earth and Space Exploration at Arizona State University.The International Workshop on Low Temperature Electronics (WOLTE) is a biennial conference devoted to the presentation and exchange of the most recent advances in the field of low temperature electronics and its applications. This international forum is open to everyone in the field.The technical program included oral presentations and posters on fundamental properties of cryogenic materials, cryogenic transistors, quantum devices and systems, astronomy and physics instrumentation, and fabrication of cryogenic devices. More than 50 scientists and engineers from various academic, government, and industrial institutions in Europe, Asia, and the Americas attended the conference.We would like to thank all speakers for their presentations and all attendees for their participation. We would also like to express our sincerest gratitude to our sponsors: Lake Shore Cryotronics, ASU NewSpace, ASU School of Earth and Space Exploration, and IRA A. Fulton Schools of Engineering for making this conference possible. (paper)

  20. Erosion–corrosion and corrosion properties of DLC coated low temperature Erosion–corrosion and corrosion properties of DLC coated low temperature

    DEFF Research Database (Denmark)

    Jellesen, Morten Stendahl; Christiansen, Thomas; Hilbert, Lisbeth Rischel


    of AISI 316 as substrate for DLC coatings are investigated. Corrosion and erosion–corrosion measurements were carried out on low temperature nitrided stainless steel AISI 316 and on low temperature nitrided stainless steel AISI 316 with a top layer of DLC. The combination of DLC and low temperature...

  1. Non-unitary probabilistic quantum computing circuit and method (United States)

    Williams, Colin P. (Inventor); Gingrich, Robert M. (Inventor)


    A quantum circuit performing quantum computation in a quantum computer. A chosen transformation of an initial n-qubit state is probabilistically obtained. The circuit comprises a unitary quantum operator obtained from a non-unitary quantum operator, operating on an n-qubit state and an ancilla state. When operation on the ancilla state provides a success condition, computation is stopped. When operation on the ancilla state provides a failure condition, computation is performed again on the ancilla state and the n-qubit state obtained in the previous computation, until a success condition is obtained.

  2. Tables of the principal unitary representations of Fedorov groups

    CERN Document Server

    Faddeyev, D K


    Tables of the Principal Unitary Representations of Fedorov Groups contains tables of all the principal representations of Fedorov groups from which all irreducible unitary representations can be obtained with the help of some standard operations. The work originated at a seminar on mathematical crystallography held in 1952-1953 at the Faculty of Mathematics and Mechanics of the Leningrad State University. The book is divided into two parts. The first part discusses the relation between the theory of representations and the generalized Fedorov groups in Shubnikov's sense. It shows that all un

  3. Classification of delocalization power of global unitary operations in terms of LOCC one-piece relocalization

    Directory of Open Access Journals (Sweden)

    Akihito Soeda


    Full Text Available We study how two pieces of localized quantum information can be delocalized across a composite Hilbert space when a global unitary operation is applied. We classify the delocalization power of global unitary operations on quantum information by investigating the possibility of relocalizing one piece of the quantum information without using any global quantum resource. We show that one-piece relocalization is possible if and only if the global unitary operation is local unitary equivalent of a controlled-unitary operation. The delocalization power turns out to reveal different aspect of the non-local properties of global unitary operations characterized by their entangling power.

  4. Reservoir Simulations of Low-Temperature Geothermal Reservoirs (United States)

    Bedre, Madhur Ganesh

    The eastern United States generally has lower temperature gradients than the western United States. However, West Virginia, in particular, has higher temperature gradients compared to other eastern states. A recent study at Southern Methodist University by Blackwell et al. has shown the presence of a hot spot in the eastern part of West Virginia with temperatures reaching 150°C at a depth of between 4.5 and 5 km. This thesis work examines similar reservoirs at a depth of around 5 km resembling the geology of West Virginia, USA. The temperature gradients used are in accordance with the SMU study. In order to assess the effects of geothermal reservoir conditions on the lifetime of a low-temperature geothermal system, a sensitivity analysis study was performed on following seven natural and human-controlled parameters within a geothermal reservoir: reservoir temperature, injection fluid temperature, injection flow rate, porosity, rock thermal conductivity, water loss (%) and well spacing. This sensitivity analysis is completed by using ‘One factor at a time method (OFAT)’ and ‘Plackett-Burman design’ methods. The data used for this study was obtained by carrying out the reservoir simulations using TOUGH2 simulator. The second part of this work is to create a database of thermal potential and time-dependant reservoir conditions for low-temperature geothermal reservoirs by studying a number of possible scenarios. Variations in the parameters identified in sensitivity analysis study are used to expand the scope of database. Main results include the thermal potential of reservoir, pressure and temperature profile of the reservoir over its operational life (30 years for this study), the plant capacity and required pumping power. The results of this database will help the supply curves calculations for low-temperature geothermal reservoirs in the United States, which is the long term goal of the work being done by the geothermal research group under Dr. Anderson at

  5. Improved Thermal-Insulation Systems for Low Temperatures (United States)

    Fesmire, James E.; Augustynowicz, Stanislaw D.


    Improved thermal-insulation materials and structures and the techniques for manufacturing them are undergoing development for use in low-temperature applications. Examples of low-temperature equipment for which these thermal insulation systems could provide improved energy efficiency include storage tanks for cryogens, superconducting electric-power-transmission equipment, containers for transport of food and other perishable commodities, and cold boxes for low-temperature industrial processes. These systems could also be used to insulate piping used to transfer cryogens and other fluids, such as liquefied natural gas, refrigerants, chilled water, crude oil, or low-pressure steam. The present thermal-insulation systems are layer composites based partly on the older class of thermal-insulation systems denoted generally as multilayer insulation (MLI). A typical MLI structure includes an evacuated jacket, within which many layers of radiation shields are stacked or wrapped close together. Low-thermal-conductivity spacers are typically placed between the reflection layers to keep them from touching. MLI can work very well when a high vacuum level (less than 10(exp-4) torr) is maintained and utmost care is taken during installation, but its thermal performance deteriorates sharply as the pressure in the evacuated space rises into the soft vacuum range [pressures greater than 0.1 torr (greater than 13 Pa)]. In addition, the thermal performance of MLI is extremely sensitive to mechanical compression and edge effects and can easily decrease from one to two orders of magnitude from its ideal value even when the MLI is kept under high vacuum condition. The present thermal-insulation systems are designed to perform well under soft vacuum level, in particular the range of 1 to 10 torr. They are also designed with larger interlayer spacings to reduce vulnerability to compression (and consequent heat leak) caused by installation and use. The superiority of these systems is the

  6. Yttrium oxide transparent ceramics by low-temperature microwave sintering

    International Nuclear Information System (INIS)

    Luo, Junming; Zhong, Zhenchen; Xu, Jilin


    Graphical abstract: The figure shows the SEM photos of the surfaces of the Y 2 O 3 transparent ceramic samples obtained by microwave sintering and vacuum sintering. It is clearly demonstrated that the grain distribution of the vacuum sintering sample is not uniform with the smallest and the largest particle size at about 2 μm and 15 μm respectively, while the grain distribution of microwave sintering sample is uniform with the average diameter at about 2–4 μm (the smallest reported so far) and with no abnormal growth-up or coarsening phenomenon. We have further found out that the smaller the grain size, the higher the mechanical and optical properties. Display Omitted Highlights: ► The microwave sintering temperature of the sample is lower compared with vacuum. ► The microwave sintering time of the sample is shorter compared with vacuum. ► The mechanical properties of the microwave sintering sample is improved greatly. ► The Y 2 O 3 grain of microwave sintering sample is the smallest reported so far. -- Abstract: Yttrium oxide (Y 2 O 3 ) transparent ceramics samples have been successfully fabricated by microwave sintering processing at relatively low temperatures. In comparison with the vacuum sintering processing, Y 2 O 3 transparent ceramics can be obtained by microwave sintering at lower sintering temperature and shorter sintering time, and they possess higher transmittances and mechanical properties. The technologies of low-temperature microwave sintering and the relationships of the microstructures and properties of the specified samples have been investigated in detail. We have found out that the low-temperature microwave sintering technique has its obvious advantages over the conventional methods in manufacturing yttrium oxide transparent ceramics.

  7. 1992--1993 low-temperature geothermal assessment program, Colorada

    Energy Technology Data Exchange (ETDEWEB)

    Cappa, J.A.; Hemborg, H.T.


    Previous assessments of Colorado`s low-temperature geothermal resources were completed by the Colorado Geological Survey in 1920 and in the mid- to late-1970s. The purpose of the 1992--1993 low-temperature geothermal resource assessment is to update the earlier physical, geochemical, and utilization data and compile computerized databases of the location, chemistry, and general information of the low-temperature geothermal resources in Colorado. The main sources of the data included published data from the Colorado Geological Survey, the US Geological Survey WATSTOR database, and the files of the State Division of Water Resources. The staff of the Colorado Geological Survey in 1992 and 1993 visited most of the known geothermal sources that were recorded as having temperatures greater than 30{degrees}C. Physical measurements of the conductivity, pH, temperature, flow rate, and notes on the current geothermal source utilization were taken. Ten new geochemical analyses were completed on selected geothermal sites. The results of the compilation and field investigations are compiled into the four enclosed Quattro Pro 4 databases. For the purposes of this report a geothermal area is defined as a broad area, usually less than 3 sq mi in size, that may have several wells or springs. A geothermal site is an individual well or spring within a geothermal area. The 1992-1993 assessment reports that there are 93 geothermal areas in the Colorado, up from the 56 reported in 1978; there are 157 geothermal sites up from the 125 reported in 1978; and a total of 382 geochemical analyses are compiled, up from the 236 reported in 1978. Six geothermal areas are recommended for further investigation: Trimble Hot Springs, Orvis Hot Springs, an area southeast of Pagosa Springs, the eastern San Luis Valley, Rico and Dunton area, and Cottonwood Hot Springs.

  8. Programming Enhancements for Low Temperature Thermal Decomposition Workstation

    Energy Technology Data Exchange (ETDEWEB)

    Igou, R.E.


    This report describes a new control-and-measurement system design for the Oak Ridge Y-12 Plant's Low Temperature Thermal Decomposition (LTTD) process. The new design addresses problems with system reliability stemming from equipment obsolescence and addresses specific functional improvements that plant production personnel have identified, as required. The new design will also support new measurement techniques, which the Y-12 Development Division has identified for future operations. The new techniques will function in concert with the original technique so that process data consistency is maintained.

  9. Postmortem magnetic resonance imaging dealing with low temperature objects

    International Nuclear Information System (INIS)

    Kobayashi, Tomoya; Shiotani, Seiji; Isobe, Tomonori


    In Japan, the medical examiner system is not widespread, the rate of autopsy is low, and many medical institutions therefore perform postmortem imaging using clinical equipment. Postmortem imaging is performed to clarify cause of death, select candidates for autopsy, make a guide map for autopsy, or provide additional information for autopsy. Findings are classified into 3 categories: cause of death and associated changes, changes induced by cardiopulmonary resuscitation, and postmortem changes. Postmortem magnetic resonance imaging shows characteristic changes in signal intensity related to low body temperature after death; they are low temperature images. (author)

  10. Simple, compact source for low-temperature air plasmas (United States)

    Sheehan, D. P.; Lawson, J.; Sosa, M.; Long, R. A.


    A simple, compact source of low-temperature, spatially and temporally uniform air plasma using a Telsa induction coil driver is described. The low-power ionization discharge plasma is localized (2 cm×0.5 cm×0.1 cm) and essentially free of arc channels. A Teflon coated rolling cylindrical electrode and dielectric coated ground plate are essential to the source's operation and allow flat test samples to be readily exposed to the plasma. The plasma is a copious source of ozone and nitrogen oxides. Its effects on various microbes are discussed.

  11. Challenges in Smart Low-Temperature District Heating Development

    DEFF Research Database (Denmark)

    Li, Hongwei; Wang, Stephen Jia


    Previous research and development shows that low temperature district heating (LTDH) system is economic feasible for low energy buildings and buildings at sparse areas. Coupling with reduced network temperature and well-designed district heating (DH) networks, LTDH can reduce network heat loss...... by up to 75% comparing with the current medium temperature district heating system. Further system efficiency improvement can be achieved through a holistic approach which includes measures such as reduced system design margin, enhanced demand side management and improved operation of decentralized heat...

  12. Early stage of diamond growth at low temperature

    Czech Academy of Sciences Publication Activity Database

    Kromka, Alexander; Potocký, Štěpán; Čermák, Jan; Rezek, Bohuslav; Zemek, Josef; Vaněček, Milan


    Roč. 17, 7-10 (2008), s. 1252-1255 ISSN 0925-9635 R&D Projects: GA AV ČR KAN400100701; GA AV ČR KAN400100652; GA MŠk(CZ) 1M06002 Grant - others: Marie Curie RTN DRIVE(XE) MRTN-CT-2004-512224 Institutional research plan: CEZ:AV0Z10100521 Keywords : nanocrystalline diamond film * AFM * SEM * low temperature CVD Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.092, year: 2008

  13. Engineered Nanostructured MEA Technology for Low Temperature Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yimin


    The objective of this project is to develop a novel catalyst support technology based on unique engineered nanostructures for low temperature fuel cells which: (1) Achieves high catalyst activity and performance; (2) Improves catalyst durability over current technologies; and (3) Reduces catalyst cost. This project is directed at the development of durable catalysts supported by novel support that improves the catalyst utilization and hence reduce the catalyst loading. This project will develop a solid fundamental knowledge base necessary for the synthetic effort while at the same time demonstrating the catalyst advantages in Direct Methanol Fuel Cells (DMFCs).

  14. Local Approach of the Charpy Test at Low Temperature


    Rossoll, A.; Tahar, M.; Berdin, C.; Piques, R.; Forget, P.; Prioul, C.; Marini, B.


    Charpy V-notch impact testing is widely used in the toughness assessment of large forged components, e.g. the pressure vessel for pressurised water reactors (PWR). At low temperature, A508 Cl.3 nuclear pressure vessel steel fails by cleavage fracture. The results reported here are part of both an experimental program and numerical investigations which aim at the establishment of a non-empirical relationship between the lower shelf Charpy V-notch energy, CVN, and the fracture toughness, KIc, o...

  15. Alternating current calorimetry at very high pressure and low temperature

    CERN Document Server

    Wilhelm, H


    The specific heat of CePd sub 2 sub . sub 0 sub 2 Ge sub 1 sub . sub 9 sub 8 has been measured with an ac calorimetric technique up to 22 GPa for temperatures in the range 0.3 K <=T <=10 K. A thermocouple allowed the temperature oscillations to be read when an ac heating current was sent through the sample. The inverse of the thermovoltage V sub a sub c recorded at low temperature exhibits a pronounced anomaly as a function of pressure. It is shown that 1/V sub a sub c extrapolated to zero temperature is a measure of the Sommerfeld coefficient gamma.

  16. Utilization of low temperature heat for environmentally friendly electricity production

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Elmegaard, Brian; Haglind, Fredrik


    and industrial processes orfrom geothermal and solar heat sources. Utilization of such heat sources makes it possible to produce electricity with no additional burning of fossil fuel, and does therefore represent an environmentally friendly alternative to fossil fuel based electricity production. Utilization......The focus on reduction of fossil fuelled electricity generation has increased the attention on exploitation of low grade heat as the energy source for electricity producing power plants. Low grade heat is heat, which isavailable at a low temperature, e.g. from waste heat from marine diesel engines...

  17. Low temperature catalytic combustion of natural gas - hydrogen - air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Newson, E.; Roth, F. von; Hottinger, P.; Truong, T.B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)


    The low temperature catalytic combustion of natural gas - air mixtures would allow the development of no-NO{sub x} burners for heating and power applications. Using commercially available catalysts, the room temperature ignition of methane-propane-air mixtures has been shown in laboratory reactors with combustion efficiencies over 95% and maximum temperatures less than 700{sup o}C. After a 500 hour stability test, severe deactivation of both methane and propane oxidation functions was observed. In cooperation with industrial partners, scaleup to 3 kW is being investigated together with startup dynamics and catalyst stability. (author) 3 figs., 3 refs.

  18. A Low Temperature Analysis of the Boundary Driven Kawasaki Process (United States)

    Maes, Christian; O'Kelly de Galway, Winny


    Low temperature analysis of nonequilibrium systems requires finding the states with the longest lifetime and that are most accessible from other states. We determine these dominant states for a one-dimensional diffusive lattice gas subject to exclusion and with nearest neighbor interaction. They do not correspond to lowest energy configurations even though the particle current tends to zero as the temperature reaches zero. That is because the dynamical activity that sets the effective time scale, also goes to zero with temperature. The result is a non-trivial asymptotic phase diagram, which crucially depends on the interaction coupling and the relative chemical potentials of the reservoirs.

  19. Sea water desalination utilizing waste heat by low temperature evaporation

    International Nuclear Information System (INIS)

    Raha, A.; Srivastava, A.; Rao, I.S.; Majumdar, M.; Srivastava, V.K.; Tewari, P.K.


    Economics of a process is controlled by management of energy and resources. Fresh water has become most valued resource in industries. Desalination is a process by which fresh water resource is generated from sea water or brackish water, but it is an energy intensive process. The energy cost contributes around 25-40% to the total cost of the desalted water. Utilization of waste heat from industrial streams is one of the ecofriendly ways to produce low cost desalted water. Keeping this in mind Low Temperature Evaporation (LTE) desalination technology utilizing low quality waste heat in the form of hot water (as low as 50 deg C) or low pressure steam (0.13 bar) has been developed for offshore and land based applications to produce high purity water (conductivity < 2μS/cm) from sea water. The probability of the scale formation is practically eliminated by operating it at low temperature and controlling the brine concentration. It also does not require elaborate chemical pretreatment of sea water except chlorination, so it has no environmental impact. LTE technology has found major applications in nuclear reactors where large quantity of low quality waste heat is available to produce high quality desalted water for make up water requirement replacing conventional ion exchange process. Successful continuous operation of 30 Te/day LTE desalination plant utilizing waste heat from nuclear research reactor has demonstrated the safety, reliability, extreme plant availability and economics of nuclear desalination by LTE technology. It is also proposed to utilize waste heat from Main Heat Transport (MHT) purification circuit of Advanced Heavy Water Reactor (AHWR) to produce about 250 Te/ day high quality desalinated water by Low Temperature Evaporation (LTE) process for the reactor make up and plant utilization. Recently we have commissioned a 50 Te/day 2-effect low temperature desalination plant with cooling tower where the specific energy and cooling water requirement are

  20. Design for ASIC reliability for low-temperature applications (United States)

    Chen, Yuan; Mojaradi, Mohammad; Westergard, Lynett; Billman, Curtis; Cozy, Scott; Burke, Gary; Kolawa, Elizabeth


    In this paper, we present a methodology to design for reliability for low temperature applications without requiring process improvement. The developed hot carrier aging lifetime projection model takes into account both the transistor substrate current profile and temperature profile to determine the minimum transistor size needed in order to meet reliability requirements. The methodology is applicable for automotive, military, and space applications, where there can be varying temperature ranges. A case study utilizing this methodology is given to design for reliability into a custom application-specific integrated circuit (ASIC) for a Mars exploration mission.

  1. Thermal Properties of Double-Aluminized Kapton at Low Temperatures (United States)

    Tuttle, J.; DiPirro, M.; Canavan, E.; Hait, T.


    Double-aluminized kapton (DAK) is commonly used in multi-layer insulation blankets in cryogenic systems. NASA plans to use individual DAK sheets in lightweight deployable shields for satellites carrying instruments. A set of these shields will reflect away thermal radiation from the sun, the earth, and the instrument's warm side and allow the instrument's cold side to radiate its own heat to deep space. In order to optimally design such a shield system, it is important to understand the thermal characteristics of DAK down to low temperatures. We describe experiments which measured the thermal conductivity and electrical resistivity down to 4 Kelvin and the emissivity down to 10 Kelvin.

  2. Low temperature gaseous nitriding and carburising of stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A.J.


    The response of various austenitic and duplex stainless steel grades to low temperature gaseous nitriding and carburising was investigated. Gaseous nitriding was performed in ammonia/hydrogen mixtures at temperatures ,723 K; gaseous carburising was carried out in carbon monoxide/hydrogen mixtures...... for temperatures (783 K. The case developed by thermochemical treatment was examined using reflected light microscopy, X-ray diffraction analysis and microhardness testing. Both nitriding and carburising led to the development of expanded austenite in the surface adjacent zone, irrespective of the phase...... constitution of the substrate. A two step process, consisting of carburising followed by nitriding, provides great flexibility with regard to adjusting the hardness–depth profile....

  3. Low Temperature Growth of Nanostructured Diamond Films on Metals (United States)

    Baker, Paul A.; Catledge, Shane A.; Vohra, Yogesh K.


    The field of nanocrystalline diamond and tetrahedral amorphous carbon films has been the focus of intense experimental activity in the last few years for applications in field emission display devices, optical windows, and tribological coatings, The choice of substrate used in most studies has typically been silicon. For metals, however, the thermal expansion mismatch between the diamond film and substrate gives rise to thermal stress that often results in delamination of the film. To avoid this problem in conventional CVD deposition low substrate temperatures (less than 700 C) have been used, often with the incorporation of oxygen or carbon monoxide to the feedgas mixture. Conventionally grown CVD diamond films are also rough and would require post-deposition polishing for most applications. Therefore, there is an obvious need to develop techniques for deposition of well-adhered, smooth nano-structured diamond films on metals for various tribological applications. In our work, nanostructured diamond films are grown on a titanium alloy substrate using a two-step deposition process. The first step is performed at elevated temperature (820 C) for 30 minutes using a H2/CH4/N2 gas mixture in order to grow a thin (approx. 600 nm) nanostructured diamond layer and improve film adhesion. The remainder of the deposition involves growth at low temperature (less than 600 C) in a H2/CH4/O2 gas mixture. Laser reflectance Interferometry (LRI) pattern during growth of a nanostructured diamond film on Ti-6Al-4V alloy. The first 30 minutes are at a high temperature of 820 C and the rest of the film is grown at a low temperature of 580 T. The fringe pattern is observed till the very end due to extremely low surface roughness of 40 nm. The continuation of the smooth nanostructured diamond film growth during low temperature deposition is confirmed by in-situ laser reflectance interferometry and by post-deposition micro-Raman spectroscopy and surface profilometry. Similar experiments

  4. High-pressure-low-temperature x-ray power diffractometer. (United States)

    Syassen, K; Holzapfel, W B


    A high-pressure technique for x-ray diffraction studies at low temperatures is described. The system consists of a Bridgman anvil type high-pressure device with either tungsten carbide or boron carbide anvils, a liquid He cryostat, and x-ray diffractometer operating in Debye-Scherrer geometry. The newly developed boron carbide anvil cell is capable of containing a liquid pressure transmitting medium. The precision of the lattice parameter determination is discussed and the effect of nonisostatic stress components on the diffraction pattern is examined.

  5. Inert Anode Life in Low Temperature Reduction Process

    Energy Technology Data Exchange (ETDEWEB)

    Bradford, Donald R.


    The production of aluminum metal by low temperature electrolysis utilizing metal non-consumable anodes and ceramic cathodes was extensively investigated. Tests were performed with traditional sodium fluoride--aluminum fluoride composition electrolytes, potassium fluoride-- aluminum fluoride electrolytes, and potassium fluoride--sodium fluoride--aluminum fluoride electrolytes. All of the Essential First-Tier Requirements of the joint DOE-Aluminum Industry Inert Anode Road Map were achieved and those items yet to be resolved for commercialization of this technology were identified. Methods for the fabrication and welding of metal alloy anodes were developed and tested. The potential savings of energy and energy costs were determined and potential environmental benefits verified.

  6. Anomalous low-temperature desorption from preirradiated rare gas solids

    International Nuclear Information System (INIS)

    Savchenko, E.V.; Gumenchuk, G.B.; Yurtaeva, E.M.; Belov, A.G.; Khyzhniy, I.V.; Frankowski, M.; Beyer, M.K.; Smith-Gicklhorn, A.M.; Ponomaryov, A.N.; Bondybey, V.E.


    The role for the exciton-induced defects in the stimulation of anomalous low-temperature desorption of the own lattice atoms from solid Ar and Ne preirradiated by an electron beam is studied. The free electrons from shallow traps-structural defects-was monitored by the measurements of a yield of the thermally induced exoelectron emission (TSEE). The reaction of recombination of self-trapped holes with electrons is considered as a source of energy needed for the desorption of atoms from the surface of preirradiated solids. A key part of the exciton-induced defects in the phenomenon observed is demonstrated

  7. Low-temperature catalytic conversion of carbonaceous materials

    Directory of Open Access Journals (Sweden)

    Tabakaev Roman B.


    Full Text Available Laws of the rate of carbon conversion in steam atmosphere at a temperature in modes of the catalytic low-temperature treatment of peat, brown coal, semi-coke from peat and brown coal are obtained by experiments. Increasing of the rate of carbon conversion in temperature range up to 500 °C is achieved by using of catalysts. The possibility of using results is associated with the burners, a working zone of which is porous filling from carbonaceous particles.

  8. Not-In-Kind Technologies for Residential and Commercial Unitary Equipment

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, S.K.


    This project was initiated by the Department of Energy in response to a request from the HVAC industry for consolidated information about alternative heating and cooling cycles and for objective comparisons of those cycles in space conditioning applications. Twenty-seven different heat pumping technologies are compared on energy use and operating costs using consistent operating conditions and assumptions about component efficiencies for all of them. This report provides a concise summary of the underlying principals of each technology, its advantages and disadvantages, obstacles to commercial development, and economic feasibility. Both positive and negative results in this study are valuable; the fact that many of the cycles investigated are not attractive for space conditioning avoids any additional investment of time or resources in evaluating them for this application. In other cases, negative results in terms of the cost of materials or in cycle efficiencies identify where significant progress needs to be made in order for a cycle to become commercially attractive. Specific conclusions are listed for many of the technologies being promoted as alternatives to electrically-driven vapor compression heat pumps using fluorocarbon refrigerants. Although reverse Rankine cycle heat pumps using hydrocarbons have similar energy use to conventional electric-driven heat pumps, there are no significant energy savings due to the minor differences in estimated steady-state performance; higher costs would be required to accommodate the use of a flammable refrigerant. Magnetic and compressor-driven metal hydride heat pumps may be able to achieve efficiencies comparable to reverse Rankine cycle heat pumps, but they are likely to have much higher life cycle costs because of high costs for materials and peripheral equipment. Both thermoacoustic and thermionic heat pumps could have lower life cycle costs than conventional electric heat pumps because of reduced equipment and maintenance costs although energy use would be higher. There are strong opportunities for gas-fired heat pumps to reduce both energy use and operating costs outside of the high cooling climates in the southeast, south central states, and the southwest. Diesel and IC (Otto) engine-driven heat pumps are commercially available and should be able to increase their market share relative to gas furnaces on a life cycle cost basis; the cost premiums associated with these products, however, make it difficult to achieve three or five year paybacks which adversely affects their use in the U.S. Stirling engine-driven and duplex Stirling heat pumps have been investigated in the past as potential gas-fired appliances that would have longer lives and lower maintenance costs than diesel and IC engine-driven heat pumps at slightly lower efficiencies. These potential advantages have not been demonstrated and there has been a low level of interest in Stirling engine-driven heat pumps since the late 1980's. GAX absorption heat pumps have high heating efficiencies relative to conventional gas furnaces and are viable alternatives to furnace/air conditioner combinations in all parts of the country outside of the southeast, south central states, and desert southwest. Adsorption heat pumps may be competitive with the GAX absorption system at a higher degree of mechanical complexity; insufficient information is available to be more precise in that assessment.

  9. Synthesis of lanthanum hydroxide nanorods by low-temperature aging

    Energy Technology Data Exchange (ETDEWEB)

    Dodd, Aaron, E-mail: [Electron Microscope Unit, University of New South Wales, Chemical Sciences Building (F10), Kensington UNSW, Sydney NSW 2052 (Australia)


    This paper presents the results of an investigation into the synthesis of La(OH){sub 3} nanorods by low-temperature aging. It was found that formation of La(OH){sub 3} nanorods was suppressed at room temperature and also by the presence of precipitation by-products, such as NaCH{sub 3}COO and residual NaOH, during the aging process. Well formed nanorods were only achieved by washing the precipitated suspension prior to aging at an elevated temperature of 60 Degree-Sign C. Unlike previous studies that utilized hydrothermal processing at high temperature and pressure, the nanorods synthesised in this study were not single crystals but were instead composed of crystals viewed down the [12{sup Macron }10] and [11{sup Macron }00] zone axes with a common [0001] growth direction. -- Highlights: Black-Right-Pointing-Pointer Investigated low temperature aging as a simple method for preparing La(OH){sub 3} nanorods. Black-Right-Pointing-Pointer Nanorod formation favored by aging in pure water at slightly elevated temperature. Black-Right-Pointing-Pointer Nanorod structure was different to that produced by hydrothermal processing.

  10. Final Report - Low Temperature Combustion Chemistry And Fuel Component Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wooldridge, Margaret [Univ. of Michigan, Ann Arbor, MI (United States)


    Recent research into combustion chemistry has shown that reactions at “low temperatures” (700 – 1100 K) have a dramatic influence on ignition and combustion of fuels in virtually every practical combustion system. A powerful class of laboratory-scale experimental facilities that can focus on fuel chemistry in this temperature range is the rapid compression facility (RCF), which has proven to be a versatile tool to examine the details of fuel chemistry in this important regime. An RCF was used in this project to advance our understanding of low temperature chemistry of important fuel compounds. We show how factors including fuel molecular structure, the presence of unsaturated C=C bonds, and the presence of alkyl ester groups influence fuel auto-ignition and produce variable amounts of negative temperature coefficient behavior of fuel ignition. We report new discoveries of synergistic ignition interactions between alkane and alcohol fuels, with both experimental and kinetic modeling studies of these complex interactions. The results of this project quantify the effects of molecular structure on combustion chemistry including carbon bond saturation, through low temperature experimental studies of esters, alkanes, alkenes, and alcohols.

  11. Crystallization and doping of amorphous silicon on low temperature plastic (United States)

    Kaschmitter, James L.; Truher, Joel B.; Weiner, Kurt H.; Sigmon, Thomas W.


    A method or process of crystallizing and doping amorphous silicon (a-Si) on a low-temperature plastic substrate using a short pulsed high energy source in a selected environment, without heat propagation and build-up in the substrate. The pulsed energy processing of the a-Si in a selected environment, such as BF3 and PF5, will form a doped micro-crystalline or poly-crystalline silicon (pc-Si) region or junction point with improved mobilities, lifetimes and drift and diffusion lengths and with reduced resistivity. The advantage of this method or process is that it provides for high energy materials processing on low cost, low temperature, transparent plastic substrates. Using pulsed laser processing a high (> C.), localized processing temperature can be achieved in thin films, with little accompanying temperature rise in the substrate, since substrate temperatures do not exceed C. for more than a few microseconds. This method enables use of plastics incapable of withstanding sustained processing temperatures (higher than C.) but which are much lower cost, have high tolerance to ultraviolet light, have high strength and good transparency, compared to higher temperature plastics such as polyimide.

  12. Brittle fracture tests at low temperature for transport cask materials

    International Nuclear Information System (INIS)

    Kosaki, Akio; Ito, Chihiro; Arai, Taku; Saegusa, Toshiari


    The IAEA Regulations for the Safe Transport of Radioactive Material were revised in 1985, and brittle fracture assessment at low temperature for transport packages are now required. This report discusses the applicability of the actual method for brittle fracture assessment of type-B transport cask materials used in JAPAN. The necessity of brittle fracture assessment at low temperature was estimated for each material of type-B transport casks used in Japan and the applicability was investigated. Dynamic fracture toughness values, K Id (J Id ), and RT NDT values of Low-Mn Carbon Steels, that are SA 350 Gr.LF1 Modify and SA 516 Gr.70 material which used in type-B transport cask body, were also obtained to check whether or not an easier and conventional test method, that prescribed in ASME CODE SECTION III, can be substituted for the dynamic fracture test method. And for bolt materials, which include 1.8Ni-0.8Cr-0.3Mo Carbon Steel and type 630 H Stainless Steel, toughness data were obtained for reference. (J.P.N.)

  13. The physics of the low-temperature plasma in Czechoslovakia

    International Nuclear Information System (INIS)

    Kracik, J.


    A survey is given of low-temperature plasma research in Czechoslovakia since 1954 and its main results are pointed out. In the first years, various processes in electric discharges and electromagnetic acceleration of plasma clusters were studied at Czechoslovak universities and in the Institute of Physics. In the study of ionization waves, Czechoslovak physicists achieved world priority. Later on, low-temperature plasma investigation began in the Institute of Plasma Physics, founded in 1959. The issues of plasma interaction with the solid state and plasma applications in plasma chemistry were studied mainly by its Department of Applied Plasma Physics. The main effort of this group, transferred recently to the Institute of Physics, is aimed at thin film production and plasma-surface interactions; similar experimental studies are also carried out at universities in Brno and Bratislava. Last but not least, arc spraying of powder materials using water-cooled plasmatrons is being developed by the Department of Plasma Technology of the Institute of Plasma Physics. (J.U.)

  14. Low temperature processing solid-state dye sensitized solar cells (United States)

    Jiang, C. Y.; Koh, W. L.; Leung, M. Y.; Chiam, S. Y.; Wu, J. S.; Zhang, J.


    A study on low temperature processed solid state dye sensitized solar cell (LT-SDSC) is reported. The LT-SDSC uses a photoelectrode with a mesoporous TiO2 (mp-TiO2) film fabricated from a binder-free nanoparticle-TiO2 paste at room temperature, and a blocking layer of an amorphous TiO2 thin film deposited by atomic layer deposition (ALD) at 150 °C. A power conversion efficiency of 1.30% is obtained from the LT-SDSC with 0.9 μm mp-TiO2 layer and 20 nm ALD-TiO2 blocking layer, in cooperating with organic indoline dyes and a hole conductor, 2,2',7,7'-Tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD). The lower electron conductivity of the low-temperature-processed mp-TiO2 film and the amorphous blocking layer is equilibrated by using smaller thicknesses of the films. Ways to further boost the LT-SDSC performance are proposed. These LT-SDSC are potentially compatible with low cost plastic substrates and show promising manufacturing potential for low cost flexible SDSCs.

  15. Low temperature growth of conformal, transparent conducting oxides (United States)

    Gordon, Roy


    Transparent conductors (TC) are essential components of many widely-used technologies, including energy conserving low-E windows, electronic displays and solar cells. Currently, TC films are made by chemical vapor deposition (CVD) or by sputtering or evaporation (PVD). CVD has generally required high temperatures (greater than 500 C), so that is not applicable to plastic substrates and some solar cells. PVD makes films with low step coverage, so textured substrates, such as those with narrow holes, cannot be coated uniformly. The most effective PVD films are based on indium, a rare and expensive element. Recently, atomic layer deposition (ALD) processes have been developed that overcome all of these limitations, allowing highly uniform and conformal coating of substrates with very narrow holes even at substrate temperatures below 100 C. The metals used in these ALD TCs are tin and/or zinc, which are abundant and inexpensive elements. In this talk, we will review these ALD processes, along with the optical, structural and electrical properties of the TCs that they produce. Applications of these low-temperature, conformal TCs will also be discussed. Record-breaking solar cells made entirely from Earth-abundant elements were enabled by these ALD processes. Transparent transistors with excellent characteristics can now be made at low temperature even on rough or textured plastic surfaces. Micro-channel plate array detectors are being produced for use in highly sensitive imaging applications.

  16. A New Low-Temperature Electrochemical Hydrocarbon and NOx Sensor. (United States)

    Sekhar, Praveen Kumar; Moore, Zachary; Aravamudhan, Shyam; Khosla, Ajit


    In this article, a new investigation on a low-temperature electrochemical hydrocarbon and NO x sensor is presented. Based on the mixed-potential-based sensing scheme, the sensor is constructed using platinum and metal oxide electrodes, along with an Yttria-Stabilized Zirconia (YSZ)/Strontium Titanate (SrTiO₃) thin-film electrolyte. Unlike traditional mixed-potential sensors which operate at higher temperatures (>400 °C), this potentiometric sensor operates at 200 °C with dominant hydrocarbon (HC) and NO x response in the open-circuit and biased modes, respectively. The possible low-temperature operation of the sensor is speculated to be primarily due to the enhanced oxygen ion conductivity of the electrolyte, which may be attributed to the space charge effect, epitaxial strain, and atomic reconstruction at the interface of the YSZ/STO thin film. The response and recovery time for the NO x sensor are found to be 7 s and 8 s, respectively. The sensor exhibited stable response even after 120 days of testing, with an 11.4% decrease in HC response and a 3.3% decrease in NO x response.

  17. Measured Performance of a Low Temperature Air Source Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R. K. [Johnson Research LLC, Pueblo West, CO (United States)


    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor 'boosted heat pump' technology. The Low Temperature Heat Pumpsystem operates with four increasing levels of capacity (heat output) as the outdoor temperature drops. The system was shown to select capacity correctly, supplying the appropriate amount of heat to the house across the full range of outdoor temperatures. The system's Coefficient of Performance (Seasonal COP, or SCOP) over two entire winters was calculated, based on measured data, to be 3.29over the first winter and 2.68 over the second winter. A second seasonal efficiency calculation by a different method yielded a SCOP of 2.78 for the first winter and 2.83 for the second winter. This second seasonal efficiency calculation was determined by comparing measured heat pump energy use to the in situ energy use with resistance heat alone. This method is the ratio of the slopes of thedaily energy use load lines.

  18. Low-temperature thermal properties of yttrium and lutetium dodecaborides

    International Nuclear Information System (INIS)

    Czopnik, A; Shitsevalova, N; Pluzhnikov, V; Krivchikov, A; Paderno, Yu; Onuki, Y


    The heat capacity (C p ) and dilatation (α) of YB 12 and LuB 12 are studied. C p of the zone-melted YB 12 tricrystal is measured in the range 2.5-70 K, of the zone-melted LuB 12 single crystal in the range 0.6-70 K, and of the LuB 12 powder sample in the range 4.3-300 K; α of the zone-melted YB 12 tricrystal and LuB 12 single crystals is measured in the range 5-200 K. At low temperatures a negative thermal expansion (NTE) is revealed for both compounds: for YB 12 at 50-70 K, for LuB 12 at 10-20 K and 60-130 K. Their high-temperature NTE is a consequence of nearly non-interacting freely oscillating metal ions (Einstein oscillators) in cavities of a simple cubic rigid Debye lattice formed by B 12 cage units. The Einstein temperatures are ∼254 and ∼164 K, and the Debye temperatures are ∼1040 K and ∼1190 K for YB 12 and LuB 12 respectively. The LuB 12 low-temperature NTE is connected with an induced low-energy defect mode. The YB 12 superconducting transition has not been detected up to 2.5 K

  19. NTD germanium: a novel material for low-temperature bolometers

    International Nuclear Information System (INIS)

    Haller, E.E.; Palaio, N.P.; Rodder, M.; Hansen, W.L.; Kreysa, E.


    Six samples of ultra-pure (absolute value N/sub A/ - N/sub D/ absolute value less than or equal to 10 11 cm -3 ), single-crystal germanium have been neutron transmutation doped with neutron doses between 7.5 x 10 16 and 1.88 x 10 18 cm -2 . After thermal annealing at 400 0 C for six hours in a pure argon atmosphere, the samples have been characterized with Hall effect and resistivity measurements between 300 and 0.3 K. Our results show that the resistivity in the low temperature, hopping conduction regime can be approximated with rho = rho 0 exp(Δ/T). The three more heavily doped samples show values for rho 0 and Δ ranging from 430 to 3.3 Ω cm and from 4.9 to 2.8 K, respectively. The excellent reproducibility of neutron transmutation doping and the values of rho 0 and Δ make NTD Ge a prime candidate for the fabrication of low temperature, low noise bolometers. The large variation in the tabulated values of the thermal neutron cross sections for the different germanium isotopes makes it clear that accurate measurements of these cross-sections for well defined neutron energy spectra would be highly desirable

  20. GEM operation in helium and neon at low temperatures (United States)

    Buzulutskov, A.; Dodd, J.; Galea, R.; Ju, Y.; Leltchouk, M.; Rehak, P.; Tcherniatine, V.; Willis, W. J.; Bondar, A.; Pavlyuchenko, D.; Snopkov, R.; Tikhonov, Y.


    We study the performance of Gas Electron Multipliers (GEMs) in gaseous He, Ne and Ne+H 2 at temperatures in the range of 2.6-293 K. In He, at temperatures between 62 and 293 K, the triple-GEM structures often operate at rather high gains, exceeding 1000. There is an indication that this high gain is achieved by the Penning effect in the gas impurities released by outgassing. At lower temperatures, the gain-voltage characteristics are significantly modified probably due to the freeze-out of impurities. In particular, the double- and single-GEM structures can operate down to 2.6 K at gains reaching only several tens at a gas density of about 0.5 g/l; at higher densities the maximum gain drops further. In Ne, the maximum gain also drops at cryogenic temperatures. The gain drop in Ne at low temperatures can be reestablished in Penning mixtures of Ne+H 2: very high gains, exceeding 10 4, have been obtained in these mixtures at 50-60 K, at a density of 9.2 g/l corresponding to that of saturated Ne vapor near 27 K. The results obtained are relevant in the fields of two-phase He and Ne detectors for solar neutrino detection and electron avalanching at low temperatures.

  1. Potential of low-temperature nuclear heat applications

    International Nuclear Information System (INIS)


    At present, more than one third of the fossil fuel currently used is being consumed to produce space heating and to meet industrial needs in many countries of the world. Imported oil still represents a large portion of this fossil fuel and despite its present relatively low price future market evolutions with consequent upward cost revisions cannot be excluded. Thus the displacement of the fossil fuel by cheaper low-temperature heat produced in nuclear power plants is a matter which deserves careful consideration. Technico-economic studies in many countries have shown that the use of nuclear heat is fully competitive with most of fossil-fuelled plants, the higher investment costs being offset by lower production cost. Another point in favour of heat generation by nuclear source is its indisputable advantage in terms of benefits to the environment. The IAEA activity plans for 1985-86 concentrate on information exchange with specific emphasis on the design criteria, operating experience, safety requirements and specifications of heat-only reactors, co-generation plants and existing power plants backfitted for additional heat applications. The information gained up to 1985 was discussed during the Advisory Group Meeting on the Potential of Low-Temperature Nuclear Heat Applications held in the Federal Institute for Reactor Research, Wuerenlingen, Switzerland in September 1985 and, is included in the present Technical Document

  2. Material for electrodes of low temperature plasma generators (United States)

    Caplan, Malcolm; Vinogradov, Sergel Evge'evich; Ribin, Valeri Vasil'evich; Shekalov, Valentin Ivanovich; Rutberg, Philip Grigor'evich; Safronov, Alexi Anatol'evich


    Material for electrodes of low temperature plasma generators. The material contains a porous metal matrix impregnated with a material emitting electrons. The material uses a mixture of copper and iron powders as a porous metal matrix and a Group IIIB metal component such as Y.sub.2O.sub.3 is used as a material emitting electrons at, for example, the proportion of the components, mass %: iron: 3-30; Y.sub.2O.sub.3:0.05-1; copper: the remainder. Copper provides a high level of heat conduction and electric conductance, iron decreases intensity of copper evaporation in the process of plasma creation providing increased strength and lifetime, Y.sub.2O.sub.3 provides decreasing of electronic work function and stability of arc burning. The material can be used for producing the electrodes of low temperature AC plasma generators used for destruction of liquid organic wastes, medical wastes, and municipal wastes as well as for decontamination of low level radioactive waste, the destruction of chemical weapons, warfare toxic agents, etc.

  3. NMR study of CeTe at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Hinderer, J. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland)]. E-mail:; Weyeneth, S.M. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Weller, M. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Gavilano, J.L. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Felder, E. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Hulliger, F. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Ott, H.R. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland)


    We present {sup 125}Te NMR measurements on CeTe powder at temperatures between 1 and 150K and in magnetic fields between 5 and 8T. CeTe is a rocksalt-type intermetallic compound. It orders antiferromagnetically at T{sub N}{approx}2.2K with a much reduced ordered moment [H.R. Ott, J.K. Kjems, F. Hulliger, Phys. Rev. Lett. 42 20 (1979) 1378]. From our low-temperature NMR spectra we infer the presence of at least three inequivalent Te sites at low temperatures. Considering the crystal structure this result is completely unexpected. The linewidths and the Knight shifts of the individual lines are significantly different and increase substantially with decreasing temperature. They follow the temperature dependence of the magnetic susceptibility above 20K. Above T{sub N}, hyperfine fields of 1.6, 0.8 and 0.0T at the three Te sites per Bohr magneton of Ce moment are deduced from Knight shift vs. magnetic susceptibility data. These values are typical for transferred hyperfine fields via conduction electrons.

  4. DU and UD-invariants of unitary groups

    International Nuclear Information System (INIS)

    Aguilera-Navarro, M.C.K.


    Four distint ways of obtaining the eigenvalues of unitary groups, in any irreducible representation, are presented. The invariants are defined according to two different contraction conventions. Their eigenvalue can be given in terms of two classes of special partial hooks associated with the young diagram characterizing the irreducible representation considered

  5. Unitary operator bases and Q-deformed algebras

    Energy Technology Data Exchange (ETDEWEB)

    Galetti, D.; Pimentel, B.M. [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil); Lima, C.L. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica. Grupo de Fisica Nuclear e Teorica e Fenomenologia de Particulas Elementares; Lunardi, J.T. [Universidade Estadual de Ponta Grossa, PR (Brazil). Dept. de Matematica e Estatistica


    Starting from the Schwinger unitary operator bases formalism constructed out of a finite dimensional state space, the well-know q-deformed commutation relation is shown to emerge in a natural way, when the deformation parameter is a root of unity. (author)

  6. Unitary operator bases and q-deformed algebras

    Energy Technology Data Exchange (ETDEWEB)

    Galleti, D.; Lunardi, J.T.; Pimentel, B.M. [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil); Lima, C.L. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica


    Starting from the Schwinger unitary operator bases formalism constructed out of a finite dimensional state space, the well-know q-deformed communication relation is shown to emergence in a natural way, when the deformation parameter is a root of unity. (author). 14 refs.

  7. Low-temperature cofire ceramic (LTCC) for extreme external conditions; Low Temperature Cofire Ceramic (LTCC) fuer extreme Belastungen

    Energy Technology Data Exchange (ETDEWEB)

    Albers, S.; Roethlingshoefer, W.; Schaich, J. [Robert Bosch GmbH (Germany)


    Electronic systems to be installed in automobile vehicles often have to be implemented on extremely limited space and are subject to high temperature and acceleration stress. Bosch has fully developed a multi-layer ceramic system as a substrate (Low-Temperature Cofire Ceramic - LTCC) and has so far delivered approx. 70 million LTCC substrates for the most diverse electronic control units. Bosch manufactures the LTCC not only for its in-house production, but also supplies these substrates to other companies. This paper describes the applications and the structure of the LTCC and describes the key aspects of reliability and quality. (orig.) [German] Elektronik im Kraftfahrzeug ist oftmals unter extrem engen Bauraeumen bei hoher Temperatur- und Beschleunigsungsbelastung zu realisieren. Als Schaltungstraeger hat Bosch ein Mehrlagenkeramiksystem (Low Temperature Cofire Ceramic - LTCC) zur industriellen Reife entwickelt und bis heute etwa 70 Millionen LTCC-Substrate zum Aufbau verschiedenster elektronischer Steuergeraete geliefert. Im Folgenden werden Einsatzgebiete und Aufbau der LTCC erlaeutert und Aspekte fuer Zuverlaessigkeit und Qualitaet aufgezeigt. (orig.)

  8. Unitary or Non-Unitary Nature of Working Memory? Evidence from Its Relation to General Fluid and Crystallized Intelligence (United States)

    Dang, Cai-Ping; Braeken, Johan; Ferrer, Emilio; Liu, Chang


    This study explored the controversy surrounding working memory: whether it is a unitary system providing general purpose resources or a more differentiated system with domain-specific sub-components. A total of 348 participants completed a set of 6 working memory tasks that systematically varied in storage target contents and type of information…

  9. Solid density, low temperature plasma formation in a capillary discharge

    International Nuclear Information System (INIS)

    Kania, D.R.; Jones, L.A.; Maestas, M.D.; Shepherd, R.L.


    This work discusses the ability of the authors to produce solid density, low temperature plasmas in polyurethane capillary discharges. The initial capillary diameter is 20 μm. The plasma is produced by discharging a one Ohm parallel plate waterline and Marx generator system through the capillary. A peak current of 340 kA in 300 ns heats the inner wall of the capillary, and the plasma expands into the surrounding material. The authors studied the evolution of the discharge using current and voltage probes, axial and radial streak photography, axial x-ray diode array and schlieren photography, and have estimated the peak temperature of the discharge to be approximately 10 eV and the density to be near 10/sup 23/cm/sup -3/. This indicates that the plasma may approach the strongly coupled regime. They discuss their interpretation of the data and compare their results with theoretical models of the plasma dynamics

  10. Low temperature friction stir welding of P91 steel

    Directory of Open Access Journals (Sweden)

    Prasad Rao Kalvala


    Full Text Available Bead-on-plate friction stir welds were made on P91 alloy with low and high rotational speeds (100 and 1000 RPM to study their effects on weld microstructural changes and impression creep behavior. Temperatures experienced by the stir zone were recorded at the weld tool tip. Different zones of welds were characterized for their microstructural changes, hardness and creep behavior (by impression creep tests. The results were compared with submerged arc fusion weld. Studies revealed that the stir zone temperature with 100 RPM was well below Ac1 temperature of P91 steel while it was above Ac3 with 1000 RPM. The results suggest that the microstructural degradation in P91 welds can be controlled by low temperature friction stir welding technique.

  11. The HD+ dissociative recombination rate coefficient at low temperature

    Directory of Open Access Journals (Sweden)

    Wolf A.


    Full Text Available The effect of the rotational temperature of the ions is considered for low-energy dissociative recombination (DR of HD+. Merged beams measurements with HD+ ions of a rotational temperature near 300 K are compared to multichannel quantum defect theory calculations. The thermal DR rate coefficient for a Maxwellian electron velocity distribution is derived from the merged-beams data and compared to theoretical results for a range of rotational temperatures. Good agreement is found for the theory with 300 K rotational temperature. For a low-temperature plasma environment where also the rotational temperature assumes 10 K, theory predicts a considerably higher thermal DR rate coefficient. The origin of this is traced to predicted resonant structures of the collision-energy dependent DR cross section at few-meV collision energies for the particular case of HD+ ions in the rotational ground state.

  12. Generator of the low-temperature heterogeneous plasma flow (United States)

    Yusupov, D. I.; Gadzhiev, M. Kh; Tyuftyaev, A. S.; Chinnov, V. F.; Sargsyan, M. A.


    A generator of low-temperature dc plasma with an expanding channel of an output electrode for gas-thermal spraying was designed and constructed. The delivery of the sprayed powder into the cathode and anode arc-binding zones or into the plasma jet below the anode binding was realized. The electrophysical characteristics of both the plasma torch and the heterogeneous plasma flow with Al2O3 powder are studied. It is shown that the current-voltage characteristic (CVC) of a plasma torch depends on the gas flow rate. If the flow rate varies from 1 to 3 g/s, the falling CVC becomes gradually increasing. The speed and temperature of the sprayed powder are determined.

  13. The low-temperature phase of morpholinium tetrafluoroborate

    Directory of Open Access Journals (Sweden)

    Tadeusz Lis


    Full Text Available The crystal structure of the low-temperature form of the title compound, C4H10NO+·BF4−, was determined at 80 K. Two reversible phase transitions, at 158/158 and 124/126 K (heating/cooling, were detected by differential scanning calorimetry for this compound, and the sequence of phase transitions was subsequently confirmed by single-crystal X-ray diffraction experiments. The asymmetric unit at 80 K consists of three BF4− tetrahedral anions and three morpholinium cations (Z′ = 3. Hydrogen-bonded morpholinium cations form chains along the [100] direction. The BF4− anions are connected to these chains by N—H...F hydrogen bonds. In the crystal structure, two different layers perpendicular to the [001] direction can be distinguished, which differ in the geometry of the hydrogen bonds between cationic and anionic species.

  14. Low temperature phase selective deposition of MnS films (United States)

    Sivakumar, R.; Dhandayuthapani, T.; Girish, M.; Sanjeeviraja, C.


    Rock salt α-MnS, Wurzite γ-MnS and mixed metastable MnS films have been successfully synthesized by chemical bath deposition method at relatively low temperature. The formation of rock salt α-MnS, wurzite γ-MnS and metastable MnS were confirmed by X-ray diffraction. Raman analysis revealed a peak at 580 cm-1 for α-MnS, 612 cm-1 for γ-MnS and 650 cm-1 for metastable MnS. α-MnS and metastable MnS exhibit a strong blue emission, whereas, γ-MnS exhibit strong yellow emission as observed from PL study.

  15. Low temperature isotope effects of hydrogen diffusion in metallic glasses

    International Nuclear Information System (INIS)

    Hofmann, A.; Kronmueller, H.


    Snoek-like relaxation peaks of Hydrogen and Deuterium in amorphous Fe 80 B 20 , Fe 40 Ni 40 P 14 B 6 and Fe 91 Zr 9 are detected. At low H, D concentrations the peaks are near 200 K and show small isotope effects of the average activation energies (anti Q H ≅ 0.6 eV, anti Q D - anti Q H ≤ 10 meV). For higher H, D-contents the peaks shift to lower temperatures around to 120 K and show distinct isotope effects in the activation energies (anti Q H ≅ 0.3 eV, anti Q D - anti Q H ≅ 30 meV) and in the amplitude of the low temperature tails of the relaxation peaks. This points to isotope mass dependent deviations from the Arrhenius law due to nonthermal tunneling processes. (orig.)

  16. Gap in the black-body spectrum at low temperature

    International Nuclear Information System (INIS)

    Schwarz, Markus; Hofmann, Ralf; Giacosa, Francesco


    We postulate that the U(1) Y factor of the Standard Model is an effective manifestation of SU(2) gauge dynamics being dynamically broken by nonperturbative effects. The modified propagation properties of the photon at low temperatures and momenta are computed. As a result of strong screening, the presence of a sizable gap in the spectral power of a black body at temperatures T = 5...20 K and for low frequencies is predicted: A table-top experiment should be able to discover this gap. If the gap is observed then the Standard Model's mechanism for electroweak symmetry-breaking is endangered by a contradiction with Big-Bang nucleosynthesis. Based on our results, we propose an explanation for the stability of cold, old, dilute, and large clouds of atomic hydrogen in between spiral arms of the outer galaxy

  17. Mapping of low temperature heat sources in Denmark

    DEFF Research Database (Denmark)

    Bühler, Fabian; Holm, Fridolin Müller; Huang, Baijia


    heat. The total accessible waste heat potential is found to be approximately 266 PJ per year with 58 % of it below 100 °C. In the natural heat category, temperatures below 20 °C originate from ambient air, sea water and shallow geothermal energy, and temperatures up to 100 °C are found for solar...... and deep geothermal energy. The theoretical solar thermal potential alone would be above 500 PJ per year. For the development of advanced thermodynamic cycles for the integration of heat sources in the Danish energy system, several areas of interest are determined. In the maritime transport sector a high......Low temperature heat sources are available in many applications, ranging from waste heat from industrial processes and buildings to geothermal and solar heat sources. Technical advancements, such as heat pumps with novel cycle design and multi-component working fluids, make the utilisation of many...

  18. The Hydrolysis of Carbonyl Sulfide at Low Temperature: A Review (United States)

    Zhao, Shunzheng; Yi, Honghong; Tang, Xiaolong; Jiang, Shanxue; Gao, Fengyu; Zhang, Bowen; Zuo, Yanran; Wang, Zhixiang


    Catalytic hydrolysis technology of carbonyl sulfide (COS) at low temperature was reviewed, including the development of catalysts, reaction kinetics, and reaction mechanism of COS hydrolysis. It was indicated that the catalysts are mainly involved metal oxide and activated carbon. The active ingredients which can load on COS hydrolysis catalyst include alkali metal, alkaline earth metal, transition metal oxides, rare earth metal oxides, mixed metal oxides, and nanometal oxides. The catalytic hydrolysis of COS is a first-order reaction with respect to carbonyl sulfide, while the reaction order of water changes as the reaction conditions change. The controlling steps are also different because the reaction conditions such as concentration of carbonyl sulfide, reaction temperature, water-air ratio, and reaction atmosphere are different. The hydrolysis of carbonyl sulfide is base-catalyzed reaction, and the force of the base site has an important effect on the hydrolysis of carbonyl sulfide. PMID:23956697

  19. Regularities in Low-Temperature Phosphatization of Silicates (United States)

    Savenko, A. V.


    The regularities in low-temperature phosphatization of silicates are defined from long-term experiments on the interaction between different silicate minerals and phosphate-bearing solutions in a wide range of medium acidity. It is shown that the parameters of the reaction of phosphatization of hornblende, orthoclase, and labradorite have the same values as for clayey minerals (kaolinite and montmorillonite). This effect may appear, if phosphotization proceeds, not after silicate minerals with a different structure and composition, but after a secondary silicate phase formed upon interaction between silicates and water and stable in a certain pH range. Variation in the parameters of the reaction of phosphatization at pH ≈ 1.8 is due to the stability of the silicate phase different from that at higher pH values.

  20. Electromagnetic Isolation Solutions in Low Temperature Cofired Ceramic (LTCC)

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Daniel; Peterson, Ken; Euler, Laurie


    Low Temperature Cofired Ceramic (LTCC) is a commercial ceramic-glass multilayer technology with compelling advantages for microelectronics, microsystems and sensors. High frequency applications require good electrical properties such as low dielectric loss and newer applications require extreme isolation from electromagnetic interference (EMI) that is even difficult to measure (-150db). Approaches to providing this isolation, once provided by via fences, have included sidewall coating and full tape thickness features (FTTF) that have been introduced by the filling of slots with via-fill compositions. Several techniques for creating these structures have been modeled for stress and temperature effects in the face of other necessary attachments, such as metallic seal frames. The relative effects of attachment media, FTTF geometry, and alternative measures will be reported. Approaches for thick film and thin film implementations are described.

  1. Single interval Rényi entropy at low temperature (United States)

    Chen, Bin; Wu, Jie-qiang


    In this paper, we calculate the Rényi entropy of one single interval on a circle at finite temperature in 2D CFT. In the low temperature limit, we expand the thermal density matrix level by level in the vacuum Verma module, and calculate the first few leading terms in e -π/ T L explicitly. On the other hand, we compute the same Rényi entropy holographically. After considering the dependence of the Rényi entropy on the temperature, we manage to fix the interval-independent constant terms in the classical part of holographic Rényi entropy. We furthermore extend the analysis in [9] to higher orders and find exact agreement between the results from field theory and bulk computations in the large central charge limit. Our work provides another piece of evidence to support holographic computation of Rényi entropy in AdS3/CFT2 correspondence, even with thermal effect.

  2. Low temperature spalling of silicon: A crack propagation study

    Energy Technology Data Exchange (ETDEWEB)

    Bertoni, Mariana; Uberg Naerland, Tine; Stoddard, Nathan; Guimera Coll, Pablo


    Spalling is a promising kerfless method for cutting thin silicon wafers while doubling the yield of a silicon ingot. The main obstacle in this technology is the high total thickness variation of the spalled wafers, often as high as 100% of the wafer thickness. It has been suggested before that a strong correlation exists between low crack velocities and a smooth surface, but this correlation has never been shown during a spalling process in silicon. The reason lies in the challenge associated to measuring such velocities. In this contribution, we present a new approach to assess, in real time, the crack velocity as it propagates during a low temperature spalling process. Understanding the relationship between crack velocity and surface roughness during spalling can pave the way to attain full control on the surface quality of the spalled wafer.


    Directory of Open Access Journals (Sweden)

    Denysova Alla


    Full Text Available One of the basic directions of perfection of heat supply systems is the tendency of transition to the low-temperature heating systems based on application of heat pump installations. We consider heat supply system with heat pump installations using subsoil waters. Numerical simulation of thermal processes in the elements of a single-stage and double-stage heat pump systems has been worked out. Values of depths of wells and their quantity, necessary for effective operation of the offered installations, and values of capacity of electric water pumps for subsoil waters unit are calculated. Capacity of compressor electric drive and coefficient of performance of heat pump for the conditions of the city of Odessa are presented.

  4. Sensitive Dependence of Gibbs Measures at Low Temperatures (United States)

    Coronel, Daniel; Rivera-Letelier, Juan


    The Gibbs measures of an interaction can behave chaotically as the temperature drops to zero. We observe that for some classical lattice systems there are interactions exhibiting a related phenomenon of sensitive dependence of Gibbs measures: An arbitrarily small perturbation of the interaction can produce significant changes in the low-temperature behavior of its Gibbs measures. For some one-dimensional XY models we exhibit sensitive dependence of Gibbs measures for a (nearest-neighbor) interaction given by a smooth function, and for perturbations that are small in the smooth category. We also exhibit sensitive dependence of Gibbs measures for an interaction on a classical lattice system with finite-state space. This interaction decreases exponentially as a function of the distance between sites; it is given by a Lipschitz continuous potential in the configuration space. The perturbations are small in the Lipschitz topology. As a by-product we solve some problems stated by Chazottes and Hochman.

  5. Thermal control systems for low temperature Shuttle payloads (United States)

    Wright, J. P.; Trucks, H.


    Greater sensitivity and longer life for future space sensor systems place more stringent demands on cooling system technology. Results are presented for a study designed to determine and evaluate low-temperature thermal control system concepts for various cooling categories in the range 3-200 K and to generate hardware development plans for undeveloped viable system concepts. The study considered Shuttle launched payloads in the 1980-1991 time frame, with 1-5 yr of life. Cooling concepts are categorized as open-cycle (expendable), closed-cycle (mechanical), solid-state, and radiative. Particular attention is given to the concepts of multistage heat pipe radiator, diode heat pipe radiator, and radiator guarded cryostat. Results are given for parametric analyses of the Vuilleumier refrigerator, the rotary reciprocating refrigerator, the solid hydrogen refrigerator, the solid hydrogen/multistage radiator hybrid cooler, and the magneto-Peltier hybrid cooler.

  6. Small reactors for low-temperature nuclear heat applications

    International Nuclear Information System (INIS)


    In accordance with the Member States' calls for information exchange in the field of nuclear heat application (NHA) two IAEA meetings were organized already in 1976 and 1977. After this ''promising period'', the development of relevant programmes in IAEA Member States was slowed down and therefore only after several years interruption a new Technical Committee Meeting with a Workshop was organized in late 1983, to review the status of NHA, after a few new specific plans appeared in some IAEA Member States in the early 1980's for the use of heat from existing or constructed NPPs and for developing nuclear heating plants (NHP). In June 1987 an Advisory Group Meeting was convened in Winnipeg, Canada, to discuss and formulate a state-of-the-art review on ''Small Reactors for Low Temperature Nuclear Heat Application''. Information on this subject gained up to 1987 in the Member States whose experts attended this meeting is embodied in the present Technical Report. Figs and tabs

  7. Ultrasonic attenuation of CdSe at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, B.J., E-mail: braulio@ula.v [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes Apartado de Correos No.1, La Hechicera, Merida 5251 (Venezuela, Bolivarian Republic of); Calderon, E.; Bracho, D.B. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes Apartado de Correos No.1, La Hechicera, Merida 5251 (Venezuela, Bolivarian Republic of); Perez, J.F. [Laboratorio de Instrumentacion Cientifica, Facultad de Ciencias, Universidad de Los Andes Apartado de Correos No.1, La Hechicera, Merida 5251 (Venezuela, Bolivarian Republic of)


    The ultrasonic attenuation of a single crystal of CdSe has been investigated over the temperature range from 1.2 to 300 K at frequencies of 10, 30 and 90 MHz. We report here the temperature dependence of the attenuation in the range 1.2-30 K for piezoactive and non-piezoactive acoustic waves. A temperature-induced relaxation for two piezoactive waves, which scale with frequency towards higher temperatures, was found. A modified Hutson and White model with a new parameter {gamma} is proposed to explain the relaxation maxima of our data and others in the literature. In this model the parameter {gamma}, which seems to be closely related to the compensation, takes into account the impurities-sound wave piezoelectric coupling. By inverting the proposed expression for the sound attenuation to obtain the electrical conductivity from the relaxation, it is found that impurity conductivity of the hopping type is the dominant conduction process at low temperatures.

  8. Ultrasonic attenuation of CdSe at low temperatures

    International Nuclear Information System (INIS)

    Fernandez, B.J.; Calderon, E.; Bracho, D.B.; Perez, J.F.


    The ultrasonic attenuation of a single crystal of CdSe has been investigated over the temperature range from 1.2 to 300 K at frequencies of 10, 30 and 90 MHz. We report here the temperature dependence of the attenuation in the range 1.2-30 K for piezoactive and non-piezoactive acoustic waves. A temperature-induced relaxation for two piezoactive waves, which scale with frequency towards higher temperatures, was found. A modified Hutson and White model with a new parameter γ is proposed to explain the relaxation maxima of our data and others in the literature. In this model the parameter γ, which seems to be closely related to the compensation, takes into account the impurities-sound wave piezoelectric coupling. By inverting the proposed expression for the sound attenuation to obtain the electrical conductivity from the relaxation, it is found that impurity conductivity of the hopping type is the dominant conduction process at low temperatures.

  9. Low-temperature behaviour of the engine oil

    Directory of Open Access Journals (Sweden)

    Vojtěch Kumbár


    Full Text Available The behaviour of engine oil is very important. In this paper has been evaluated temperature dependence kinematic viscosity of engine oils in the low temperatures. Five different commercially distributed engine oils (primarily intended for automobile engines with viscosity class 0W–40, 5W–40, 10W–40, 15W–40, and 20W–40 have been evaluated. The temperature dependence kinematic viscosity has been observed in the range of temperature from −15 °C to 15 °C (for all oils. Considerable temperature dependence kinematic viscosity was found and demonstrated in case of all samples, which is in accordance with theoretical assumptions and literature data. Mathematical models have been developed and tested. Temperature dependence dynamic viscosity has been modeled using a polynomials 3rd and 4th degree. The proposed models can be used for prediction of flow behaviour of oils. With monitoring and evaluating we can prevent technical and economic losses.

  10. Work station for low temperature positron annihilation studies

    International Nuclear Information System (INIS)

    Chaturvedi, T.P.; Venkiteswaran, S.; Pujari, P.K.


    This report describes the automation implemented in the low temperature Positron Annihilation Spectroscopy studies system. Temperature programmer and controller (Lakeshore 330) is interfaced to PC-AT through an IEEE-488 add-on card. Through this data can be read and written to the temperature controller and it can be handled remotely. The PC- AT also houses the PCA-II card. Software (TEMP330.EXE) was developed to communicate with the temperature controller. A master software is also developed under which TEMP330.EXE and PCAII.EXE should run. Another program DATASEG.EXE creates a user file to store the temperature points given by user over which data acquisition is required. This has not only widened the scope of the positron research, but also helps achieve result with better precision. (author)

  11. Low temperature performance of lithium/silver vanadium oxide cells (United States)

    Takeuchi, E. S.; Tuhovak, D. R.; Post, C. J.


    Lithium/silver vanadium oxide cells for low temperature applications have been developed. Prismatic and spirally wound AA cells were tested under constant load discharge of 0.3 to 1.8 amps or pulse discharge of 0.225 or 1.0 amps at temperatures from -40 to 25 C. At -40 C with current densities of 2.5 mA/cm2, 23 percent of theoretical capacity was achieved under constant load discharge and 40 percent of theoretical capacity was achieved under pulse test. Self-discharge estimates of 0.7 percent per year at 25 C were obtained from microcalorimetry. Preliminary safety testing of the cells revealed no violent performance under short circuit or crush tests.

  12. Towards spontaneous parametric down-conversion at low temperatures

    Directory of Open Access Journals (Sweden)

    Akatiev Dmitrii


    Full Text Available The possibility of observing spontaneous parametric down-conversion in doped nonlinear crystals at low temperatures, which would be useful for combining heralded single-photon sources and quantum memories, is studied theoretically. The ordinary refractive index of a lithium niobate crystal doped with magnesium oxide LiNbO3:MgO is measured at liquid nitrogen and helium temperatures. On the basis of the experimental data, the coefficients of the Sellmeier equation are determined for the temperatures from 5 to 300 K. In addition, a poling period of the nonlinear crystal has been calculated for observing type-0 spontaneous parametric down-conversion (ooo-synchronism at the liquid helium temperature under pumping at the wavelength of λp = 532 nm and emission of the signal field at the wavelength of λs = 794 nm, which corresponds to the resonant absorption line of Tm3+ doped ions.

  13. Low temperature phonon boundary scattering in slightly rough Silicon nanowires (United States)

    Ghossoub, Marc; Valavala, Krishna; Seong, Myunghoon; Azeredo, Bruno; Sadhu, Jyothi S.; Sinha, Sanjiv


    Nanostructured materials have lower thermal conductivities than the bulk and are promising candidates for thermoelectric applications. In particular, measurements on single silicon nanowires show a reduction in thermal conductivity below the Casimir limit. This reduction increases with surface roughness but the trend and its connection to phonon boundary scattering are still elusive. Here, we measure the thermal conductivity of single silicon nanowires fabricated using metal-assisted chemical etching. High resolution TEM imaging shows crystalline wires with slightly rough surfaces. Their statistical correlation lengths (5-15 nm) and RMS heights (0.8-1.5 nm) are in a range where perturbation-based wave scattering theory is still applicable. We use the thermal conductivity data to extract the frequency dependence of phonon boundary scattering at low temperatures (10-40 K) and show agreement with multiple scattering theory. This work provides insight into enhancing the thermoelectric performance of nanostructures.

  14. Low temperature magnetic characterization of EuO1-x (United States)

    Rimal, Gaurab; Tang, Jinke

    EuO is a widely studied magnetic semiconductor. It is an ideal case of a Heisenberg ferromagnet as well as a model magnetic polaron system. The interesting aspect of this material is the existance of magnetic polarons in the low temperature region. We study the properties of oxygen deficient EuO prepared by pulsed laser deposition. Besides normal ferromagnetic transitions near 70K and 140K, we observe a different transition at 16K. We also observe a shift in the coercivity for field cooling versus zero field cooling. Possible mechanisms driving these behaviors will be discussed. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering (DEFG02-10ER46728) and by the School of Energy Resources of the University of Wyoming.

  15. Amorphous gallium oxide grown by low-temperature PECVD

    KAUST Repository

    Kobayashi, Eiji


    Owing to the wide application of metal oxides in energy conversion devices, the fabrication of these oxides using conventional, damage-free, and upscalable techniques is of critical importance in the optoelectronics community. Here, the authors demonstrate the growth of hydrogenated amorphous gallium oxide (a-GaO:H) thin-films by plasma-enhanced chemical vapor deposition (PECVD) at temperatures below 200 °C. In this way, conformal films are deposited at high deposition rates, achieving high broadband transparency, wide band gap (3.5-4 eV), and low refractive index (1.6 at 500 nm). The authors link this low refractive index to the presence of nanoscale voids enclosing H, as indicated by electron energy-loss spectroscopy. This work opens the path for further metal-oxide developments by low-temperature, scalable and damage-free PECVD processes.

  16. Low temperature thermal expansion of liquid Helium-4

    International Nuclear Information System (INIS)

    Berthold, J.E.


    Results of a measurement of the thermal expansion of liquid He-4 are presented along the saturated vapor pressure curve at low temperatures (0.1 - 0.6 0 K). The thermal expansion is related to the low momentum region of the He-4 excitation spectrum, and the results of this measurement are analyzed to gain information concerning deviations from linearity in the phonon region of the spectrum. The data is also compared with theoretical predictions of Alrich and Bhatt and McMillan and with the thermal expansion measurement of Van Degrift. In addition a discussion of previous experimental evidence on the shape of the low momentum region of the dispersion relation is presented

  17. Low-temperature excitations within the Bethe approximation

    International Nuclear Information System (INIS)

    Biazzo, I; Ramezanpour, A


    We propose the variational quantum cavity method to construct a minimal energy subspace of wavevectors that are used to obtain some upper bounds for the energy cost of the low-temperature excitations. Given a trial wavefunction we use the cavity method of statistical physics to estimate the Hamiltonian expectation and to find the optimal variational parameters in the subspace of wavevectors orthogonal to the lower-energy wavefunctions. To this end, we write the overlap between two wavefunctions within the Bethe approximation, which allows us to replace the global orthogonality constraint with some local constraints on the variational parameters. The method is applied to the transverse Ising model and different levels of approximations are compared with the exact numerical solutions for small systems. (paper)

  18. Magnetic resonance studies of atomic hydrogen gas at low temperatures

    International Nuclear Information System (INIS)

    Hardy, W.N.; Morrow, M.; Jochemsen, R.; Statt, B.W.; Kubik, P.R.; Marsolais, R.M.; Berlinsky, A.J.; Landesman, A.


    Using a pulsed low temperature discharge in a closed cell containing H 2 and 4 He, we have been able to store a low density (approximately 10 12 atoms/cc) gas of atomic hydrogen for periods of order one hour in zero magnetic field and T=1 K. Pulsed magnetic resonance at the 1420 MHz hyperfine transition has been used to study a number of the properties of the gas, including the recombination rate H + H + 4 He→H 2 + 4 He, the hydrogen spin-exchange relaxation rates, the diffusion coefficient of H in 4 He gas and the pressure shift of the hyperfine frequency due to the 4 He buffer gas. Here we discuss the application of hyperfine frequency shifts as a probe of the H-He potential, and as a means for determining the binding energy of H on liquid helium

  19. Anodes for Solid Oxide Fuel Cells Operating at Low Temperatures

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain

    An important issue that has limited the potential of Solid Oxide Fuel Cells (SOFCs) for portable applications is its high operating temperatures (800-1000 ºC). Lowering the operating temperature of SOFCs to 400-600 ºC enable a wider material selection, reduced degradation and increased lifetime....... On the other hand, low-temperature operation poses serious challenges to the electrode performance. Effective catalysts, redox stable electrodes with improved microstructures are the prime requisite for the development of efficient SOFC anodes. The performance of Nb-doped SrT iO3 (STN) ceramic anodes...... at 400ºC. The potential of using WO3 ceramic as an alternative anode materials has been explored. The relatively high electrode polarization resistance obtained, 11 Ohm cm2 at 600 ºC, proved the inadequate catalytic activity of this system for hydrogen oxidation. At the end of this thesis...

  20. Gasoline Ultra Efficient Fuel Vehicle with Advanced Low Temperature Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Confer, Keith [Delphi Automotive Systems, LLC, Troy, MI (United States)


    The objective of this program was to develop, implement and demonstrate fuel consumption reduction technologies which are focused on reduction of friction and parasitic losses and on the improvement of thermal efficiency from in-cylinder combustion. The program was executed in two phases. The conclusion of each phase was marked by an on-vehicle technology demonstration. Phase I concentrated on short term goals to achieve technologies to reduce friction and parasitic losses. The duration of Phase I was approximately two years and the target fuel economy improvement over the baseline was 20% for the Phase I demonstration. Phase II was focused on the development and demonstration of a breakthrough low temperature combustion process called Gasoline Direct- Injection Compression Ignition (GDCI). The duration of Phase II was approximately four years and the targeted fuel economy improvement was 35% over the baseline for the Phase II demonstration vehicle. The targeted tailpipe emissions for this demonstration were Tier 2 Bin 2 emissions standards.

  1. Ultra sound absorption measurements in rock samples at low temperatures (United States)

    Herminghaus, C.; Berckhemer, H.


    A new technique, comparable with the reverberation method in room acoustics, is described. It allows Q-measurements at rock samples of arbitrary shape in the frequency range of 50 to 600 kHz in vacuum (.1 mtorr) and at low temperatures (+20 to -180 C). The method was developed in particular to investigate rock samples under lunar conditions. Ultrasound absorption has been measured at volcanics, breccia, gabbros, feldspar and quartz of different grain size and texture yielding the following results: evacuation raises Q mainly through lowering the humidity in the rock. In a dry compact rock, the effect of evacuation is small. With decreasing temperature, Q generally increases. Between +20 and -30 C, Q does not change much. With further decrease of temperature in many cases distinct anomalies appear, where Q becomes frequency dependent.

  2. Spectral manifestation of distorted forms metalloporphyrins at low temperatures (United States)

    Starukhin, Aleksander; Gorski, Aleksander; Kijak, Michal


    Different spectral forms of a set of metalloporphyrins with Mg (II), Zn (II), Pd (II) and Pt (II) ions in solid solutions (Shpol'skii matrices, solid tetrahydrofuran and solid rare gas matrices) have been detected in the absorption and luminescence spectra at cryogenic temperatures. The spectral manifestation of a planar form, as well as two distorted forms for Mg- and Zn-porpyrins was formed in the ground electronic state at low temperatures. An existence of two spectral forms of Pd and Pt-porphyrins was observed in their phosphorescence spectra. In the case of Mg-porphyrin the spectral shift between positions of 0-0 transitions the planar and first distorted spectral forms is about 220 cm-1.

  3. Spectral manifestation of distorted forms metalloporphyrins at low temperatures

    Directory of Open Access Journals (Sweden)

    Starukhin Aleksander


    Full Text Available Different spectral forms of a set of metalloporphyrins with Mg (II, Zn (II, Pd (II and Pt (II ions in solid solutions (Shpol'skii matrices, solid tetrahydrofuran and solid rare gas matrices have been detected in the absorption and luminescence spectra at cryogenic temperatures. The spectral manifestation of a planar form, as well as two distorted forms for Mg- and Zn-porpyrins was formed in the ground electronic state at low temperatures. An existence of two spectral forms of Pd and Pt-porphyrins was observed in their phosphorescence spectra. In the case of Mg-porphyrin the spectral shift between positions of 0-0 transitions the planar and first distorted spectral forms is about 220 cm-1.

  4. The Future of Low Temperature Germanium as Dark Matter Detectors

    CERN Multimedia

    CERN. Geneva


    The Weakly Interactive Massive Particles (WIMPs) represent one of the most attractive candidates for the dark matter in the universe. With the combination of experiments attempting to detect WIMP scattering in the laboratory, of searches for their annihilation in the cosmos and of their potential production at the LHC, the next five years promise to be transformative. I will review the role played so far by low temperature germanium detectors in the direct detection of WIMPs. Because of its high signal to noise ratio, the simultaneous measurement of athermal phonons and ionization is so far the only demonstrated approach with zero-background. I will argue that this technology can be extrapolated to a target mass of the order of a tonne at reasonable cost and can keep playing a leading role, complementary to noble liquid technologies. I will describe in particular GEODM, the proposed Germanium Observatory for Dark Matter at the US Deep Underground Science and Engineering Laboratory (DUSEL).

  5. Design and Modelling of Small Scale Low Temperature Power Cycles

    DEFF Research Database (Denmark)

    Wronski, Jorrit

    he work presented in this report contributes to the state of the art within design and modelling of small scale low temperature power cycles. The study is divided into three main parts: (i) fluid property evaluation, (ii) expansion device investigations and (iii) heat exchanger performance...... times and below 10−7 away from the phase boundaries.Regarding expansion devices for small scale organic Rankine cycle (ORC) systems,this work focussed on reciprocating machines. A prototype of a reciprocating expander with a swept volume of 736 cm3 was tested and modelled. he model was written in object......-oriented Modelica code and was included in the thermo Cycle framework for small scale ORC systems. Special attention was paid to the valve system and a control method for variable expansion ratios was introduced based on a cogeneration scenario. Admission control based on evaporator and condenser conditions...

  6. California low-temperature geothermal resources update: 1993

    Energy Technology Data Exchange (ETDEWEB)

    Youngs, L.G.


    The US Department of Energy -- Geothermal Division (DOE/GD) recently sponsored the Low-Temperature Geothermal Resources and Technology Transfer Program to bring the inventory of the nation`s low- and moderate-temperature geothermal resources up to date and to encourage development of the resources. The Oregon Institute of Technology, Geo-Heat Center (OIT/GHC) and the University of Utah Research Institute (UURI) established subcontracts and coordinated the project with the state resource teams from the western states that participated in the program. The California Department of Conservation, Division of Mines and Geology (DMG) entered into contract numbered 1092--023(R) with the OIT/GHC to provide the California data for the program. This report is submitted in fulfillment of that contract.

  7. Method for low temperature preparation of a noble metal alloy (United States)

    Even, Jr., William R.


    A method for producing fine, essentially contamination free, noble metal alloys is disclosed. The alloys comprise particles in a size range of 5 to 500 nm. The method comprises 1. A method for preparing a noble metal alloy at low temperature, the method comprising the steps of forming solution of organometallic compounds by dissolving the compounds into a quantity of a compatible solvent medium capable of solvating the organometallic, mixing a portion of each solution to provide a desired molarity ratio of ions in the mixed solution, adding a support material, rapidly quenching droplets of the mixed solution to initiate a solute-solvent phase separation as the solvent freezes, removing said liquid cryogen, collecting and freezing drying the frozen droplets to produce a dry powder, and finally reducing the powder to a metal by flowing dry hydrogen over the powder while warming the powder to a temperature of about C.

  8. Material variability as measured by low temperature electrical resistivity. (United States)

    Clark, A. F.; Tryon, P. V.


    Low temperature electrical resistivity was used to determine the material variability (1) between different manufacturers, (2) between different heats from the same manufacturer, and (3) within a given heat for Al 2024, Al-5% Mg alloys, Inconel 718, A286 stainless, and AISI 316. Generally, the coefficient of variation for solution annealed alloys ranged from 1.2 to 14% between manufacturers, 0.8 to 5.1% between heats, and 0.1 to 1.6% within a heat with stainless steels at the low ends and Al 2024 at the high ends. The variability is increased if the material is in a precipitation-hardened condition. A statistical analysis suggests that the variability within a heat is non-normal.

  9. Low temperature oxidation of hydrocarbons using an electrochemical reactor

    DEFF Research Database (Denmark)

    Ippolito, Davide

    at different reaction temperatures. The study of the effect of the infiltration of different electroactive materials on the electrode behavior has been carried on by the use of electrochemical impedance spectroscopy (EIS). Both the methods have been employed to understand the relationship between the catalytic...... conversion was a complex function of multiple variables: the microstructure of the backbone, the polarization resistance of the electrodes, both at OCV and under polarization, the electrical and morphological properties of the infiltrated material and the specific reaction conditions like the propene......, the LSM/CGO exhibited a strong electrode activation and increase of catalytic activity after the application of prolonged polarization. The infiltration of LSM/CGO backbone with Ce0.9Gd0.1O1.95, heat treated at low temperature to form a continuous layer on the electrode, was the best compromise to obtain...

  10. Ecological implications of metabolic compensation at low temperatures in salamanders. (United States)

    Catenazzi, Alessandro


    Global warming is influencing the biology of the world's biota. Temperature increases are occurring at a faster pace than that experienced by organisms in their evolutionary histories, limiting the organisms' response to new conditions. Mechanistic models that include physiological traits can help predict species' responses to warming. Changes in metabolism at high temperatures are often examined; yet many species are behaviorally shielded from high temperatures. Salamanders generally favor cold temperatures and are one of few groups of metazoans to be most species-rich in temperate regions. I examined variation in body temperature, behavioral activity, and temperature dependence of resting heart rate, used as a proxy for standard metabolic rate, in fire salamanders (Salamandra salamandra). Over 26 years, I found that salamanders are behaviorally active at temperatures as low as 1 °C, and aestivate at temperatures above 16 °C. Infrared thermography indicates limited thermoregulation opportunities for these nocturnal amphibians. Temperature affects resting heart rate, causing metabolic depression above 11 °C, and metabolic compensation below 8 °C: heart rate at 3 °C is 224% the expected heart rate. Thus, salamanders operating at low temperatures during periods of peak behavioral activity are able to maintain a higher metabolic rate than the rate expected in absence of compensation. This compensatory mechanism has important ecological implications, because it increases estimated seasonal heart rates. Increased heart rate, and thus metabolism, will require higher caloric intake for field-active salamanders. Thus, it is important to consider a species performance breadth over the entire temperature range, and particularly low temperatures that are ecologically relevant for cold tolerant species such as salamanders.

  11. Ecological implications of metabolic compensation at low temperatures in salamanders

    Directory of Open Access Journals (Sweden)

    Alessandro Catenazzi


    Full Text Available Global warming is influencing the biology of the world’s biota. Temperature increases are occurring at a faster pace than that experienced by organisms in their evolutionary histories, limiting the organisms’ response to new conditions. Mechanistic models that include physiological traits can help predict species’ responses to warming. Changes in metabolism at high temperatures are often examined; yet many species are behaviorally shielded from high temperatures. Salamanders generally favor cold temperatures and are one of few groups of metazoans to be most species-rich in temperate regions. I examined variation in body temperature, behavioral activity, and temperature dependence of resting heart rate, used as a proxy for standard metabolic rate, in fire salamanders (Salamandra salamandra. Over 26 years, I found that salamanders are behaviorally active at temperatures as low as 1 °C, and aestivate at temperatures above 16 °C. Infrared thermography indicates limited thermoregulation opportunities for these nocturnal amphibians. Temperature affects resting heart rate, causing metabolic depression above 11 °C, and metabolic compensation below 8 °C: heart rate at 3 °C is 224% the expected heart rate. Thus, salamanders operating at low temperatures during periods of peak behavioral activity are able to maintain a higher metabolic rate than the rate expected in absence of compensation. This compensatory mechanism has important ecological implications, because it increases estimated seasonal heart rates. Increased heart rate, and thus metabolism, will require higher caloric intake for field-active salamanders. Thus, it is important to consider a species performance breadth over the entire temperature range, and particularly low temperatures that are ecologically relevant for cold tolerant species such as salamanders.

  12. Glycemic index: effect of food storage under low temperature

    Directory of Open Access Journals (Sweden)

    Marina Cassab Carreira


    Full Text Available This study was carried out to evaluate the influence of food storage under low temperature (-20ºC and the resistant starch formation, both on the glycemic index (GI. The GI of only cooked and cooked and stored foods under -20ºC for 30 days was evaluated in short-term tests with humans. Significant increase on the RS content was evidenced for all the stored foods. The food storage resulted in a significant decrease on the GI of beans and chick-peas; the GI of pasta remained the same and the GI of corn meal increased. Thus, the RS formation showed reduced influence on the glycemic index. The storage of starchy foods under low temperature can collaborate to the RS intake but its effect on the GI will depend on the characteristics of the carbohydrates of each food.O estudo foi realizado para avaliar a influência do armazenamento de alimentos sob baixa temperatura e a formação de amido resistente sobre o índice glicêmico (IG. O IG de alimentos cozidos ou cozidos e armazenados a -20ºC por 30 dias foi avaliado em ensaios de curta duração com humanos. Aumento significativo no conteúdo de AR foi evidenciado para todos os alimentos armazenados. O armazenamento dos alimentos resultou em significativa redução no IG do feijão e do grão de bico. O IG do macarrão foi o mesmo e da polenta sofreu aumento. Desta forma, a evidenciada formação de AR mostrou reduzida influência no IG. O armazenamento de alimentos fonte de amido sob baixa temperatura pode colaborar com a ingestão de AR, mas o efeito sobre o IG vai depender das características dos carboidratos de cada alimento.

  13. Low temperature gamma sterilization of a bioresorbable polymer, PLGA (United States)

    Davison, Lisa; Themistou, Efrosyni; Buchanan, Fraser; Cunningham, Eoin


    Medical devices destined for insertion into the body must be sterilised before implantation to prevent infection or other complications. Emerging biomaterials, for example bioresorbable polymers, can experience changes in their properties due to standard industrial sterilization processes. Gamma irradiation is one of the most reliable, large scale sterilization methods, however it can induce chain scission, cross-linking or oxidation reactions in polymers. sterilization at low temperature or in an inert atmosphere has been reported to reduce the negative effects of gamma irradiation. The aim of this study was to investigate the impact of low temperature sterilization (at -80 °C) when compared to sterilization at ambient temperature (25 °C) both in inert atmospheric conditions of nitrogen gas, on poly(lactide co-glycolide) (PLGA). PLGA was irradiated at -80 and 25 °C at 40 kGy in a nitrogen atmosphere. Samples were characterised using differential scanning calorimetry (DSC), tensile test, Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy and gel permeation chromatography (GPC). The results showed that the molecular weight was significantly reduced as was the glass transition temperature, an indication of chain scission. FTIR showed small changes in chemical structure in the methyl and carbonyl groups after irradiation. Glass transition temperature was significantly different between irradiation at -80 °C and irradiation at 25 °C, however this was a difference of only 1 °C. Ultimately, the results indicate that the sterilization temperature used does not affect PLGA when carried out in a nitrogen atmosphere.

  14. Design of stirling engine operating at low temperature difference

    Directory of Open Access Journals (Sweden)

    Sedlák Josef


    Full Text Available There are many sources of free energy available in the form of heat that is often simply wasted. The aim of this paper is to design and build a low temperature differential Stirling engine that would be powered exclusively from heat sources such as waste hot water or focused solar rays. A prototype is limited to a low temperature differential modification because of a choice of ABSplus plastic as a construction material for its key parts. The paper is divided into two parts. The first part covers a brief history of Stirling engine and its applications nowadays. Moreover, it describes basic principles of its operation that are supplemented by thermodynamic relations. Furthermore, an analysis of applied Fused Deposition Modelling has been done since the parts with more complex geometry had been manufactured using this additive technology. The second (experimental part covers 4 essential steps of a rapid prototyping method - Computer Aided Design of the 3D model of Stirling engine using parametric modeller Autodesk Inventor, production of its components using 3D printer uPrint, assembly and final testing. Special attention was devoted to last two steps of the process since the surfaces of the printed parts were sandpapered and sprayed. Parts, where an ABS plus plastic would have impeded the correct function, had been manufactured from aluminium and brass by cutting operations. Remaining parts had been bought in a hardware store as it would be uneconomical and unreasonable to manufacture them. Last two chapters of the paper describe final testing, mention the problems that appeared during its production and propose new approaches that could be used in the future to improve the project.

  15. Analysis of Low Temperature Organic Rankine Cycles for Solar Applications (United States)

    Li, Yunfei

    The present work focuses on Organic Rankine Cycle (ORC) systems and their application to low temperature waste heat recovery, combined heat and power as well as off-grid solar power generation applications. As CO_2 issues come to the fore front and fossil fuels become more expensive, interest in low grade heat recovery has grown dramatically in the past few years. Solar energy, as a clean, renewable, pollution-free and sustainable energy has great potential for the use of ORC systems. Several ORC solutions have been proposed to generate electricity from low temperature sources. The ORC systems discussed here can be applied to fields such as solar thermal, biological waste heat, engine exhaust gases, small-scale cogeneration, domestic boilers, etc. The current work presents a thermodynamic and economic analysis for the use of ORC systems to convert solar energy or low exergy energy to generate electrical power. The organic working fluids investigated here were selected to investigate the effect of the fluid saturation temperature on the performance of ORCs. The working fluids under investigation are R113, R245fa, R123, with boiling points between 40°C and 200°C at pressures from 10 kPa to 10 MPa. Ambient temperature air at 20oC to 30oC is utilized as cooling resource, and allowing for a temperature difference 10°C for effective heat transfer. Consequently, the working fluids are condensed at 40°C. A combined first- and second-law analysis is performed by varying some system independent parameters at various reference temperatures. The present work shows that ORC systems can be viable and economical for the applications such as waste heat use and off-grid power generation even though they are likely to be more expensive than grid power.

  16. Nanostructural studies on monoelaidin-water systems at low temperatures. (United States)

    Kulkarni, Chandrashekhar V


    In recent years, lipid based nanostructures have increasingly been used as model membranes to study various complex biological processes. For better understanding of such phenomena, it is essential to gain as much information as possible for model lipid structures under physiological conditions. In this paper, we focus on one of such lipids--monoelaidin (ME)--for its polymorphic nanostructures under varying conditions of temperature and water content. In the recent contribution (Soft Matter, 2010, 6, 3191), we have reported the phase diagram of ME above 30 °C and compared with the phase behavior of other lipids including monoolein (MO), monovaccenin (MV), and monolinolein (ML). Remarkable phase behavior of ME, stabilizing three bicontinuous cubic phases, motivates its study at low temperatures. Current studies concentrate on the low-temperature (ME and subsequent reconstruction of its phase diagram over the entire temperature-water composition space (temperature, 0-76 °C; and water content, 0-70%). The polymorphs found for the monoelaidin-water system include three bicontinuous cubic phases, i.e., Ia3d, Pn3m, and Im3m, and lamellar phases which exhibit two crystalline (L(c1) and L(c0)), two gel (L(β) and L(β*)), and a fluid lamellar (L(α)) states. The fluid isotropic phase (L(2)) was observed only for lower hydrations (<20%), whereas hexagonal phase (H(2)) was not found under studied conditions. Nanostructural parameters of these phases as a function of temperature and water content are presented together with some molecular level calculations. This study might be crucial for perception of the lyotropic phase behavior as well as for designing nanostructural assemblies for potential applications. © 2011 American Chemical Society

  17. Summaries of reports of the 30. Conference on low-temperature physics. Pt. 2. Quantum liquids and crystals. Low-temperature solid-state physics. Electron phenomena at low temperatures

    International Nuclear Information System (INIS)


    Report thesises of the conference on the low-temperature physics are presented. The fundamental problems of solids low-temperature physics, quantum liquids and crystals. Specific features are considered of structures, magnetic and thermodynamic properties of metals, alloys and other materials, and also optical and electric properties of thin films

  18. Microstructure in hardened cement pastes measured by mercury intrusion porosimetry and low temperature microcalorimetry

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Baroghel, V.B.; Künzel, H.M.


    , image analysis, mercury intrusion porosimetry and low temperature microcalorimetry.The present paper is dealing with cumulated pore size distributions measured by mercury intrusion porosimetry (MIP) from two laboratories (LCPC, IBP) and low temperature microcalorimetry (CAL) from one laboratory (BKM...


    The objective of the study was to evaluate several low-temperature characteristics of Challenge 5100, a new protective clothing material developed by Chemical Fabrics Corporation. The low temperature characteristics of three other protective clothing materials were also evaluated...

  20. Development of a sample environment for neutron diffraction at low temperature

    International Nuclear Information System (INIS)

    Lee, Jeong Soo; Lee, Chang Hee; Choi, Yong Nam


    This report contains the development of low temperature sample environment for the neutron diffraction and its utilization techniques. With this research, a low temperature experimental facility of T=10-300 K was developed. We measured magnetic peak of La 1 .4Sr 1 .6Mn 2 O 7 due to low temperature phase transition successfully by this unit installed at the sample table of HRPD. Therefore, the research capability for various materials under the low temperature was expanded

  1. Low temperature impact testing of welded structural wrought iron (United States)

    Rogers, Zachary

    During the second half of the 19th century, structural wrought iron was commonly used in construction of bridges and other structures. Today, these remaining structures are still actively in use and may fall under the protection of historic preservation agencies. Continued use and protection leads to the need for inspection, maintenance, and repair of the wrought iron within these structures. Welding can be useful to achieve the appropriate repair, rehabilitation, or replacement of wrought iron members. There is currently very little published on modern welding techniques for historic wrought iron. There is also no pre-qualified method for this welding. The demand for welding in the repair of historic structural wrought iron has led to a line of research investigating shielded metal arc welding (SMAW) of historic wrought iron at the University of Colorado Denver. This prior research selected the weld type and other weld specifications to try and achieve a recognized specific welding procedure using modern SMAW technology and techniques. This thesis continues investigating SMAW of historic wrought iron. Specifically, this thesis addresses the toughness of these welds from analysis of the data collected from performing Charpy V-Notch (CVN) Impact Tests. Temperature was varied to observe the material response of the welds at low temperature. The wrought iron used in testing was from a historic vehicle bridge in Minnesota, USA. This area, and many other areas with wrought iron structures, can experience sustained or fluctuating temperatures far below freezing. Investigating the toughness of welds in historic wrought iron at these temperatures is necessary to fully understand material responses of the existing structures in need of maintenance and repair. It was shown that welded wrought iron is tougher and more ductile than non-welded wrought iron. In regards to toughness, welding is an acceptable repair method. Information on wrought iron, low temperature failure

  2. Unitary-matrix models as exactly solvable string theories (United States)

    Periwal, Vipul; Shevitz, Danny


    Exact differential equations are presently found for the scaling functions of models of unitary matrices which are solved in a double-scaling limit, using orthogonal polynomials on a circle. For the case of the simplest, k = 1 model, the Painleve II equation with constant 0 is obtained; possible nonperturbative phase transitions exist for these models. Equations are presented for k = 2 and 3, and discussed with a view to asymptotic behavior.

  3. On relevant boundary perturbations of unitary minimal models

    International Nuclear Information System (INIS)

    Recknagel, A.; Roggenkamp, D.; Schomerus, V.


    We consider unitary Virasoro minimal models on the disk with Cardy boundary conditions and discuss deformations by certain relevant boundary operators, analogous to tachyon condensation in string theory. Concentrating on the least relevant boundary field, we can perform a perturbative analysis of renormalization group fixed points. We find that the systems always flow towards stable fixed points which admit no further (non-trivial) relevant perturbations. The new conformal boundary conditions are in general given by superpositions of 'pure' Cardy boundary conditions

  4. Emergent phase space description of unitary matrix model (United States)

    Chattopadhyay, Arghya; Dutta, Parikshit; Dutta, Suvankar


    We show that large N phases of a 0 dimensional generic unitary matrix model (UMM) can be described in terms of topologies of two dimensional droplets on a plane spanned by eigenvalue and number of boxes in Young diagram. Information about different phases of UMM is encoded in the geometry of droplets. These droplets are similar to phase space distributions of a unitary matrix quantum mechanics (UMQM) ((0 + 1) dimensional) on constant time slices. We find that for a given UMM, it is possible to construct an effective UMQM such that its phase space distributions match with droplets of UMM on different time slices at large N . Therefore, large N phase transitions in UMM can be understood in terms of dynamics of an effective UMQM. From the geometry of droplets it is also possible to construct Young diagrams corresponding to U( N) representations and hence different large N states of the theory in momentum space. We explicitly consider two examples: single plaquette model with Tr U 2 terms and Chern-Simons theory on S 3. We describe phases of CS theory in terms of eigenvalue distributions of unitary matrices and find dominant Young distributions for them.

  5. Ancilla-assisted sequential approximation of nonlocal unitary operations (United States)

    Saberi, Hamed


    We consider the recently proposed “no-go” theorem of Lamata [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.101.180506 101, 180506 (2008)] on the impossibility of sequential implementation of global unitary operations with the aid of an itinerant ancillary system and view the claim within the language of Kraus representation. By virtue of an extremely useful tool for analyzing entanglement properties of quantum operations, namely, operator-Schmidt decomposition, we provide alternative proof to the no-go theorem and also study the role of initial correlations between the qubits and ancilla in sequential preparation of unitary entanglers. Despite the negative response from the no-go theorem, we demonstrate explicitly how the matrix-product operator (MPO) formalism provides a flexible structure to develop protocols for sequential implementation of such entanglers with an optimal fidelity. The proposed numerical technique, which we call variational matrix-product operator (VMPO), offers a computationally efficient tool for characterizing the “globalness” and entangling capabilities of nonlocal unitary operations.

  6. Low-temperature synthesis of silicon carbide powder using shungite

    Energy Technology Data Exchange (ETDEWEB)

    Gubernat, A.; Pichor, W.; Lach, R.; Zientara, D.; Sitarz, M.; Springwald, M.


    The paper presents the results of investigation the novel and simple method of synthesis of silicon carbide. As raw material for synthesis was used shungite, natural mineral rich in carbon and silica. The synthesis of SiC is possible in relatively low temperature in range 1500–1600°C. It is worth emphasising that compared to the most popular method of SiC synthesis (Acheson method where the temperature of synthesis is about 2500°C) the proposed method is much more effective. The basic properties of products obtained from different form of shungite and in wide range of synthesis temperature were investigated. The process of silicon carbide formation was proposed and discussed. In the case of synthesis SiC from powder of raw materials the product is also in powder form and not requires any additional process (crushing, milling, etc.). Obtained products are pure and after grain classification may be used as abrasive and polishing powders. (Author)

  7. Optimization criteria for low temperature waste heat utilization

    International Nuclear Information System (INIS)

    Kranebitter, F.


    A special case in this field is the utilization of very low temperature waste heat. The temperature level under consideration in this paper is in the range between the body temperature of human beings and their environment. The waste heat from power generation and industrial processes is also considered. Thermal energy conversion will be mainly accomplished by heat cycles where discharged waste heat is reverse proportional to the upper cycle temperature. Limiting this upper cycle temperature by technological reasons the optimization of the heat cycle will depend on the nature of the cycle itself and specially on the temperature selected for the heat discharge. The waste heat discharge is typical for the different kinds of heat cycles and the paper presents the four most important of them. Feasible heat transfer methods and their economic evaluations are discussed and the distillation processes will be the basis for further considerations. The waste heat utilization for distillation purposes could be realized by three different cycles, the open cycle, the closed cycle and the multy cycle. Resulting problems as deaeration of large water streams and removal of the dissolved gases and their solutions are also discussed. (M.S.)

  8. Rheological behavior of drilling fluids under low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Lomba, Rosana F.T.; Sa, Carlos H.M. de; Brandao, Edimir M. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas]. E-mails: rlomba, chsa,


    The so-called solid-free fluids represent a good alternative to drill through productive zones. These drill-in fluids are known to be non-damaging to the formation and their formulation comprise polymers, salts and acid soluble solids. Xanthan gum is widely used as viscosifier and modified starch as fluid loss control additive. The salts most commonly used are sodium chloride and potassium chloride, although the use of organic salt brines has been increasing lately. Sized calcium carbonate is used as bridging material, when the situation requires. The low temperatures encountered during deep water drilling demand the knowledge of fluid rheology at this temperature range. The rheological behavior of drill-in fluids at temperatures as low as 5 deg C was experimentally evaluated. Special attention was given to the low shear rate behavior of the fluids. A methodology was developed to come up with correlations to calculate shear stress variations with temperature. The developed correlations do not depend on a previous choice of a rheological model. The results will be incorporated in a numerical simulator to account for temperature effects on well bore cleaning later on. (author)

  9. The Consumers Characteristics Analysis of Low Temperature Home Delivery

    Directory of Open Access Journals (Sweden)

    Shu-Fang Lai


    Full Text Available Because of technological advancements and the popularity of the Internet, online shopping has become an important shopping channel for consumers. Because people increasingly eat out, more consumers shop online, and food products are collected from convenience stores, or frozen food home delivery services are used. This study used questionnaire surveys to analyze the consumption habits of residents who shop online for frozen foods in the urban areas of northern Taiwan (Taipei City and New Taipei City. We distributed and collected 548 questionnaires, of which 484 were valid. Descriptive statistics, a chi-square test, and logistics regression analysis were used to analyze consumer characteristics, as well as important influential factors. The research results indicated that most online shoppers were women, and the top 3 factors influencing their purchasing decisions were freshness, delivery convenience, and ordering convenience. Participants in the age group of 40-49 years old, living in the urban area of New Taipei City, without junior college education, and with less than 10,000 NTD monthly incomes, were less likely to purchase frozen foods using low-temperature logistics services.

  10. Low-temperature densification of high-Tc superconductors

    International Nuclear Information System (INIS)

    Capone, D.W. II


    It is believed that the weak-link behavior in YBa 2 Cu 3 O 7 , 123 bulk materials results from the presence of non-superconducting second phases coating the grain boundaries of sintered 123 compacts. These second phases result from the BaCuO 2 - CuO eutectic, which is a liquid at sintering temperatures above 870 degrees C. Sintering below this temperature results in low densities (ca. 70/% of the theoretical density). Sintering above 870 degrees C produces dense samples via liquid-phase sintering, resulting in the grain boundary phases mentioned above. The authors report the results of a series of low-temperature densification experiments designed to produce 100% dense ceramic samples at temperatures below 870 degrees C. Room-temperature swaging, using standard powder metallurgy techniques, has been used for form fibers having green (unsintered) densities greater than 90% of the theoretical density of the 123. A warm extrusion technique (T ≥ 300 degrees C) has also been used to produce 100% dense 123 compacts. In both cases, after fabrication, the oxygen content of the 123 materials is near 7.0. However, x- ray diffraction experiments show that the cation lattice is disordered, and the materials are not superconducting. These materials can be ordered using suitable posts-annealing techniques. The effect of time and temperature on the degree of ordering and the superconductivity is presented

  11. Post-irradiation grafting of tetrafluoroethylene at low temperatures

    International Nuclear Information System (INIS)

    Barkalov, I.M.; Kiryukhin, D.P.; Muydinov, M.R.


    Low-temperature postirradiation grafting of tetrafluoroethylene (TFE) to polyolefines and silicone elastomers was the subject of study. After preliminary dissolution of TFE in the polymer at 273 0 K the system was slowly cooled to 77 0 K. In this process a certain part of TFE in polyolefines (ethylene-propylene copolymer and polypropylene) is retained by the vitreous polymer matrix. When slowly heated after radiolysis at 77 0 K this system shows graft polymerization of dissolved TFE after T/sub g/. The graft copolymer is soluble and its IR spectra contain absorption bands characteristic of polytetrafluoroethylene. In polydimethylsiloxane rubber (SKT) the dissolved TFE when frozen to 77 0 K remains sorbed between the SKT crystallites rather than in a separate phase. When those radiolyzed samples are heated the graft-polymerization occurs primarily over the temperature range between the TFE and SKT melting points. The technique provides for 100 to 150% grafting of TFE. This method also permits grafting to silicone rubbers and to several other polymers and elastomers

  12. A leech capable of surviving exposure to extremely low temperatures.

    Directory of Open Access Journals (Sweden)

    Dai Suzuki

    Full Text Available It is widely considered that most organisms cannot survive prolonged exposure to temperatures below 0°C, primarily because of the damage caused by the water in cells as it freezes. However, some organisms are capable of surviving extreme variations in environmental conditions. In the case of temperature, the ability to survive subzero temperatures is referred to as cryobiosis. We show that the ozobranchid leech, Ozobranchus jantseanus, a parasite of freshwater turtles, has a surprisingly high tolerance to freezing and thawing. This finding is particularly interesting because the leach can survive these temperatures without any acclimation period or pretreatment. Specifically, the leech survived exposure to super-low temperatures by storage in liquid nitrogen (-196°C for 24 hours, as well as long-term storage at temperatures as low as -90°C for up to 32 months. The leech was also capable of enduring repeated freeze-thaw cycles in the temperature range 20°C to -100°C and then back to 20°C. The results demonstrated that the novel cryotolerance mechanisms employed by O. jantseanus enable the leech to withstand a wider range of temperatures than those reported previously for cryobiotic organisms. We anticipate that the mechanism for the observed tolerance to freezing and thawing in O. jantseanus will prove useful for future studies of cryopreservation.

  13. Foundations of low-temperature plasma physics—an introduction (United States)

    von Keudell, A.; Schulz-von der Gathen, V.


    The use of plasmas as a reactive mixture of ions, electrons and neutrals is at the core of numerous technologies in industry, enabling applications in microelectronics, automotives, packaging, environment and medicine. Recently, even the use of plasmas in medical applications has made great progress. The dominant character of a plasma is often its non equilibrium nature with different temperatures for the individual species in a plasma, the ions, electrons and neutrals. This opens up a multitude of reaction pathways which are inaccessible to conventional methods in chemistry, for example. The understanding of plasmas requires expertise in plasma physics, plasma chemistry and in electrical engineering. This first paper in a series of foundation papers on low temperature plasma science is intended to provide the very basics of plasmas as a common starting point for the more in-depth discussion of particular plasma generation methods, plasma modeling and diagnostics in the other foundation papers. In this first paper of the series, the common terminology, definitions and main concepts are introduced. The covered aspects start with the basic definitions and include further plasma equilibria, particle collisions and transport, sheaths and discharge breakdowns.

  14. Foundations of modelling of nonequilibrium low-temperature plasmas (United States)

    Alves, L. L.; Bogaerts, A.; Guerra, V.; Turner, M. M.


    This work explains the need for plasma models, introduces arguments for choosing the type of model that better fits the purpose of each study, and presents the basics of the most common nonequilibrium low-temperature plasma models and the information available from each one, along with an extensive list of references for complementary in-depth reading. The paper presents the following models, organised according to the level of multi-dimensional description of the plasma: kinetic models, based on either a statistical particle-in-cell/Monte-Carlo approach or the solution to the Boltzmann equation (in the latter case, special focus is given to the description of the electron kinetics); multi-fluid models, based on the solution to the hydrodynamic equations; global (spatially-average) models, based on the solution to the particle and energy rate-balance equations for the main plasma species, usually including a very complete reaction chemistry; mesoscopic models for plasma–surface interaction, adopting either a deterministic approach or a stochastic dynamical Monte-Carlo approach. For each plasma model, the paper puts forward the physics context, introduces the fundamental equations, presents advantages and limitations, also from a numerical perspective, and illustrates its application with some examples. Whenever pertinent, the interconnection between models is also discussed, in view of multi-scale hybrid approaches.

  15. Low temperature high frequency coaxial pulse tube for space application

    Energy Technology Data Exchange (ETDEWEB)

    Charrier, Aurelia; Charles, Ivan; Rousset, Bernard; Duval, Jean-Marc [SBT, UMR-E CEA / UJF-Grenoble 1, INAC, 17, rue des Martyrs, Grenoble, F-38054 (France); Daniel, Christophe [CNES, 18, avenue Edouard Belin, Toulouse, F-31401 (France)


    The 4K stage is a critical step for space missions. The Hershel mission is using a helium bath, which is consumed day by day (after depletion, the space mission is over) while the Plank mission is equipped with one He4 Joule-Thomson cooler. Cryogenic chain without helium bath is a challenge for space missions and 4.2K Pulse-Tube working at high frequency (around 30Hz) is one option to take it up. A low temperature Pulse-Tube would be suitable for the ESA space mission EChO (Exoplanet Characterisation Observatory, expected launch in 2022), which requires around 30mW cooling power at 6K; and for the ESA space mission ATHENA (Advanced Telescope for High ENergy Astrophysics), to pre-cool the sub-kelvin cooler (few hundreds of mW at 15K). The test bench described in this paper combines a Gifford-McMahon with a coaxial Pulse-Tube. A thermal link is joining the intercept of the Pulse-Tube and the second stage of the Gifford-McMahon. This intercept is a separator between the hot and the cold regenerators of the Pulse-Tube. The work has been focused on the cold part of this cold finger. Coupled with an active phase shifter, this Pulse-Tube has been tested and optimized and temperatures as low as 6K have been obtained at 30Hz with an intercept temperature at 20K.

  16. Improving the low temperature properties of biodiesel fuel

    Energy Technology Data Exchange (ETDEWEB)

    Bhale, Purnanand Vishwanathrao; Deshpande, Nishikant V.; Thombre, Shashikant B. [Visvesvaraya National Institute of Technology, Mechanical Engineering, South Ambazari Road, Near Bajaj Nagar, 440011 Nagpur, Maharashtra (India)


    The use of biodiesel as a diesel fuel extender and lubricity improver is rapidly increasing. While most of the properties of biodiesel are comparable to petroleum based diesel fuel, improvement of its low temperature flow characteristic still remains one of the major challenges when using biodiesel as an alternative fuel for diesel engines. The biodiesel fuels derived from fats or oils with significant amounts of saturated fatty compounds will display higher cloud points and pour points. This paper is aimed to investigate the cold flow properties of 100% biodiesel fuel obtained from Madhuca indica, one of the important species in the Indian context. In this paper, the cold flow properties of biodiesel were evaluated with and without pour point depressants towards the objectives of identifying the pumping and injecting of these biodiesel in CI engines under cold climates. Effect of ethanol, kerosene and commercial additive on cold flow behavior of this biodiesel was studied. A considerable reduction in pour point has been noticed by using these cold flow improvers. The performance and emission with ethanol blended Mahua biodiesel fuel and ethanol-diesel blended Mahua biodiesel fuel have also been studied. A considerable reduction in emission was obtained. Ethanol blended biodiesel is totally a renewable, viable alternative fuel for improved cold flow behavior and better emission characteristics without affecting the engine performance. (author)

  17. Selective and low temperature transition metal intercalation in layered tellurides (United States)

    Yajima, Takeshi; Koshiko, Masaki; Zhang, Yaoqing; Oguchi, Tamio; Yu, Wen; Kato, Daichi; Kobayashi, Yoji; Orikasa, Yuki; Yamamoto, Takafumi; Uchimoto, Yoshiharu; Green, Mark A.; Kageyama, Hiroshi


    Layered materials embrace rich intercalation reactions to accommodate high concentrations of foreign species within their structures, and find many applications spanning from energy storage, ion exchange to secondary batteries. Light alkali metals are generally most easily intercalated due to their light mass, high charge/volume ratio and in many cases strong reducing properties. An evolving area of materials chemistry, however, is to capture metals selectively, which is of technological and environmental significance but rather unexplored. Here we show that the layered telluride T2PTe2 (T=Ti, Zr) displays exclusive insertion of transition metals (for example, Cd, Zn) as opposed to alkali cations, with tetrahedral coordination preference to tellurium. Interestingly, the intercalation reactions proceed in solid state and at surprisingly low temperatures (for example, 80 °C for cadmium in Ti2PTe2). The current method of controlling selectivity provides opportunities in the search for new materials for various applications that used to be possible only in a liquid.

  18. Low-temperature graphene synthesis using microwave plasma CVD (United States)

    Yamada, Takatoshi; Kim, Jaeho; Ishihara, Masatou; Hasegawa, Masataka


    The graphene chemical vapour deposition (CVD) technique at substrate temperatures around 300 °C by a microwave plasma sustained by surface waves (surface wave plasma chemical vapour deposition, SWP-CVD) is discussed. A low-temperature, large-area and high-deposition-rate CVD process for graphene films was developed. It was found from Raman spectra that the deposited films on copper (Cu) substrates consisted of high-quality graphene flakes. The fabricated graphene transparent conductive electrode showed uniform optical transmittance and sheet resistance, which suggests the possibility of graphene for practical electrical and optoelectronic applications. It is intriguing that graphene was successfully deposited on aluminium (Al) substrates, for which we did not expect the catalytic effect to decompose hydrocarbon and hydrogen molecules. We developed a roll-to-roll SWP-CVD system for continuous graphene film deposition towards industrial mass production. A pair of winder and unwinder systems of Cu film was installed in the plasma CVD apparatus. Uniform Raman spectra were confirmed over the whole width of 297 mm of Cu films. We successfully transferred the deposited graphene onto PET films, and confirmed a transmittance of about 95% and a sheet resistance of less than 7 × 105 Ω/sq.

  19. Experimental results on a low-temperature magnetic refrigerator

    International Nuclear Information System (INIS)

    Barclay, J.A.; Stewart, W.F.; Overton, W.C.; Candler, R.J.; Harkleroad, O.D.


    A Carnot-cycle magnetic refrigerator has been designed, built, and tested in the temperature range of approx.4 K to approx.15 K. Gadolinium gallium garnet in the rim of a wheel is the refrigerant. The wheel rim rotates through a gap between two superconducting Helmholtz coils that produce a magnetic field of up to 6 T. Helium gas is used as the heat-transfer fluid in the hot and cold regions of the wheel. The refrigerator performance has been measured in an open-cycle flow system because no suitable low-temperature helium gas pumps were available for closed loop circulation of helium gas. Over one watt of cooling power with a temperature span of several degrees was achieved. At low frequencies the cooling power and temperature changes of the refrigerator match the entropy-temperature data used in the design. Problems associated with friction and gas mixing limit the performance at frequencies above about 0.1 Hz. Separate friction measurements suggest that gas flow control is the dominant problem that needs to be solved before significant improvement in refrigerator operation can be expected. The present measured efficiency is about 20% of Carnot if the drive motor efficiency is ignored. With friction and other losses in the drive motor mechanism, the overall efficiency is approx.1% of Carnot

  20. Model for low temperature oxidation during long term interim storage

    International Nuclear Information System (INIS)

    Desgranges, Clara; Bertrand, Nathalie; Gauvain, Danielle; Terlain, Anne; Poquillon, Dominique; Monceau, Daniel


    For high-level nuclear waste containers in long-term interim storage, dry oxidation will be the first and the main degradation mode during about one century. The metal lost by dry oxidation over such a long period must be evaluated with a good reliability. To achieve this goal, modelling of the oxide scale growth is necessary and this is the aim of the dry oxidation studies performed in the frame of the COCON program. An advanced model based on the description of elementary mechanisms involved in scale growth at low temperatures, like partial interfacial control of the oxidation kinetics and/or grain boundary diffusion, is developed in order to increase the reliability of the long term extrapolations deduced from basic models developed from short time experiments. Since only few experimental data on dry oxidation are available in the temperature range of interest, experiments have also been performed to evaluate the relevant input parameters for models like grain size of oxide scale, considering iron as simplified material. (authors)

  1. Localized temperature stability in Low Temperature Cofired Ceramics (LTCC).

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Steven Xunhu; Hsieh, Lung-Hwa.


    The base dielectrics of commercial low temperature cofired ceramics (LTCC) systems have a temperature coefficient of resonant frequency ({tau}{sub f}) in the range -50 {approx} -80 ppm/C. In this research we explored a method to realize zero or near zero {tau}{sub f} resonators by incorporating {tau}{sub f} compensating materials locally into a multilayer LTCC structure. To select composition for {tau}{sub f} adjustment, {tau}{sub f} compensating materials with different amount of titanates were formulated, synthesized, and characterized. Chemical interactions and physical compatibility between the {tau}{sub f} modifiers and the host LTCC dielectrics were investigated. Studies on stripline (SL) resonator panels with multiple compensating dielectrics revealed that: 1) compositions using SrTiO{sub 3} provide the largest {tau}{sub f} adjustment among titanates, 2) the {tau}{sub f} compensation is proportional to the amount of SrTiO{sub 3} in compensating materials, as well as the thickness of the compensating layer, and 3) the most effective {tau}{sub f} compensation is achieved when the compensating dielectric is integrated next to the SL. Using the effective dielectric constant of a heterogeneous layered dielectric structure, results from Method of Momentum (MoM) electromagnetic simulations are consistent with the experimental observations.

  2. Low temperature catalytic reforming of heptane to hydrogen and syngas

    Directory of Open Access Journals (Sweden)

    M.E.E. Abashar


    Full Text Available The production of hydrogen and syngas from heptane at a low temperature is studied in a circulating fast fluidized bed membrane reactor (CFFBMR. A thin film of palladium-based membrane is employed to the displacement of the thermodynamic equilibrium for high conversion and yield. A mathematical model is developed to simulate the reformer. A substantial improvement of the CFFBMR is achieved by implementing the thin hydrogen membrane. The results showed that almost complete conversion of heptane and 46.25% increase of exit hydrogen yield over the value without membrane are achieved. Also a wide range of the H2/CO ratio within the recommended industrial range is obtained. The phenomena of high spikes of maximum nature at the beginning of the CFFBMR are observed and explanation offered. The sensitivity analysis results have shown that the increase of the steam to carbon feed ratio can increase the exit hydrogen yield up to 108.29%. It was found that the increase of reaction side pressure at a high steam to carbon feed ratio can increase further the exit hydrogen yield by 49.36% at a shorter reactor length. Moreover, the increase of reaction side pressure has an important impact in a significant decrease of the carbon dioxide and this is a positive sign for clean environment.

  3. Enhancement of low-temperature thermometry by strong coupling (United States)

    Correa, Luis A.; Perarnau-Llobet, Martí; Hovhannisyan, Karen V.; Hernández-Santana, Senaida; Mehboudi, Mohammad; Sanpera, Anna


    We consider the problem of estimating the temperature T of a very cold equilibrium sample. The temperature estimates are drawn from measurements performed on a quantum Brownian probe strongly coupled to it. We model this scenario by resorting to the canonical Caldeira-Leggett Hamiltonian and find analytically the exact stationary state of the probe for arbitrary coupling strength. In general, the probe does not reach thermal equilibrium with the sample, due to their nonperturbative interaction. We argue that this is advantageous for low-temperature thermometry, as we show in our model that (i) the thermometric precision at low T can be significantly enhanced by strengthening the probe-sampling coupling, (ii) the variance of a suitable quadrature of our Brownian thermometer can yield temperature estimates with nearly minimal statistical uncertainty, and (iii) the spectral density of the probe-sample coupling may be engineered to further improve thermometric performance. These observations may find applications in practical nanoscale thermometry at low temperatures—a regime which is particularly relevant to quantum technologies.

  4. Low temperature particle detectors with magnetic penetration thermometers

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, N.; Hengstler, D.; Kampkoetter, A.; Kempf, S.; Pies, C.; Pizzigoni, G.; Ranitzsch, P.; Schaefer, S.; Uhl, S.; Gastaldo, L.; Fleischmann, A.; Enss, C. [Kirchhoff-Institut fuer Physik, INF 227, 69120 Heidelberg (Germany)


    We present low temperature micro-calorimeters based on a novel sensor concept, the Magnetic Penetration Thermometers (MPTs). The MPTs make use of the temperature dependence of the critical magnetic field and the penetration depth of a superconducting sensor. The superconducting sensor is inductively coupled to a superconducting pick-up coil which also provides a bias magnetic field. The flux in the pick-up coil depends on the position of the interface between normal and superconducting regions in the sensor which in turn is a steep function of temperature. The change of magnetic flux upon the absorption of a particle is read-out by low-noise high-bandwidth dc-SQUIDs. Similar to metallic magnetic calorimeters, MPTs operate in a wide range of temperature and without intrinsic bias power dissipation. We present the results of numerical simulations for the signal size and energy resolution for various superconducting films based on a simple thermo-dynamical model, as well as first experimental results.

  5. Low temperature ozone oxidation of solid waste surrogates (United States)

    Nabity, James A.; Lee, Jeffrey M.


    Solid waste management presents a significant challenge to human spaceflight and especially, long-term missions beyond Earth orbit. A six-month mission will generate over 300 kg of solid wastes per crewmember that must be dealt with to eliminate the need for storage and prevent it from becoming a biological hazard to the crew. There are several methods for the treatment of wastes that include oxidation via ozone, incineration, microbial oxidation or pyrolysis and physical methods such as microwave drying and compaction. In recent years, a low temperature oxidation process using ozonated water has been developed for the chemical conversion of organic wastes to CO2 and H2O. Experiments were conducted to evaluate the rate and effectiveness with which ozone oxidized several different waste materials. Increasing the surface area by chopping or shredding the solids into small pieces more than doubled the rate of oxidation. A greater flow of ozone and agitation of the ozonated water system also increased processing rates. Of the materials investigated, plastics have proven the most difficult to oxidize. The processing of plastics above the glass transition temperatures caused the plastics to clump together which reduced the exposed surface area, while processing at lower temperatures reduced surface reaction kinetics.

  6. Low temperature spent fuel oxidation under tuff repository conditions

    International Nuclear Information System (INIS)

    Einziger, R.E.; Woodley, R.E.


    The Nevada Nuclear Waste Storage Investigations Project is studying the suitability of tuffaceous rocks at Yucca Mountain, Nye County, Nevada, for high level waste disposal. The oxidation state of LWR spent fuel in a tuff repository may be a significant factor in determining its ability to inhibit radionuclide migration. Long term exposure at low temperatures to the moist air expected in a tuff repository is expected to increase the oxidation state of the fuel. A program is underway to determine the spent fuel oxidation mechanisms which might be active in a tuff repository. Initial work involves a series of TGA experiments to determine the effectiveness of the technique and to obtain preliminary oxidation data. Tests were run at 200 0 C and 225 0 C for as long as 720 hours. Grain boundary diffusion appears to open up a greater surface area for oxidation prior to onset of bulk diffusion. Temperature strongly influences the oxidation rates. The effect of moisture is small but readily measurable. 25 refs., 7 figs., 4 tabs

  7. Selective and low temperature transition metal intercalation in layered tellurides (United States)

    Yajima, Takeshi; Koshiko, Masaki; Zhang, Yaoqing; Oguchi, Tamio; Yu, Wen; Kato, Daichi; Kobayashi, Yoji; Orikasa, Yuki; Yamamoto, Takafumi; Uchimoto, Yoshiharu; Green, Mark A.; Kageyama, Hiroshi


    Layered materials embrace rich intercalation reactions to accommodate high concentrations of foreign species within their structures, and find many applications spanning from energy storage, ion exchange to secondary batteries. Light alkali metals are generally most easily intercalated due to their light mass, high charge/volume ratio and in many cases strong reducing properties. An evolving area of materials chemistry, however, is to capture metals selectively, which is of technological and environmental significance but rather unexplored. Here we show that the layered telluride T2PTe2 (T=Ti, Zr) displays exclusive insertion of transition metals (for example, Cd, Zn) as opposed to alkali cations, with tetrahedral coordination preference to tellurium. Interestingly, the intercalation reactions proceed in solid state and at surprisingly low temperatures (for example, 80 °C for cadmium in Ti2PTe2). The current method of controlling selectivity provides opportunities in the search for new materials for various applications that used to be possible only in a liquid. PMID:27966540

  8. High pressure apparatus for neutron scattering at low temperature

    International Nuclear Information System (INIS)

    Munakata, Koji; Uwatoko, Yoshiya; Aso, Naofumi


    Effects of pressure on the physical properties are very important for understanding highly correlated electron systems, in which pressure-induced attractive phenomena such as superconductivity and magnetically ordered non-Fermi liquid have been observed. Up to now, many scientists have developed a lot of high pressure apparatus for each purpose. The characteristic features of various materials and pressure transmitting media for use of high pressure apparatus are reported. Then, two kinds of clamp type high-pressure cell designed for low-temperature neutron diffraction measurements are shown; one is a piston cylinder type high-pressure cell which can be attached to the dilution refrigerator, and the other one is a newly-developed cubic anvil type high-pressure cell which can generate pressure above 7GPa. We also introduce the results of magnetic neutron scattering under pressure on a pressure-induced superconducting ferromagnet UGe 2 in use of the piston cylinder type clamp cell, and those on an iron arsenide superconductor SrFe 2 As 2 in use of the cubic anvil type clamp cell. (author)

  9. Development of decay energy spectroscopy using low temperature detectors. (United States)

    Jang, Y S; Kim, G B; Kim, K J; Kim, M S; Lee, H J; Lee, J S; Lee, K B; Lee, M K; Lee, S J; Ri, H C; Yoon, W S; Yuryev, Y N; Kim, Y H


    We have developed a high-resolution detection technique for measuring the energy and activity of alpha decay events using low-temperature detectors. A small amount of source material containing alpha-emitting radionuclides was enclosed in a 4π metal absorber. The energy of the alpha particles as well as that of the recoiled nuclides, low-energy electrons, and low-energy x-rays and γ-rays was converted into thermal energy of the gold absorber. A metallic magnetic calorimeter serving as a fast and sensitive thermometer was thermally attached to the metal absorber. In the present report, experimental demonstrations of Q spectroscopy were made with a new meander-type magnetic calorimeter. The thermal connection between the temperature sensor and the absorber was established with annealed gold wires. Each alpha decay event in the absorber resulted in a temperature increase of the absorber and the temperature sensor. Using the spectrum measured for a drop of (226)Ra solution in a 4π gold absorber, all of the alpha emitters in the sample were identified with a demonstration of good detector linearity. The resolution of the (226)Ra spectrum showed a 3.3 keV FWHM at its Q value together with an expected gamma escape peak at the energy shifted by its γ-ray energy. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Formation of Hydroxylamine in Low-Temperature Interstellar Model Ices. (United States)

    Tsegaw, Yetsedaw A; Góbi, Sándor; Förstel, Marko; Maksyutenko, Pavlo; Sander, Wolfram; Kaiser, Ralf I


    We irradiated binary ice mixtures of ammonia (NH 3 ) and oxygen (O 2 ) ices at astrophysically relevant temperatures of 5.5 K with energetic electrons to mimic the energy transfer process that occurs in the track of galactic cosmic rays. By monitoring the newly formed molecules online and in situ utilizing Fourier transform infrared spectroscopy complemented by temperature-programmed desorption studies with single-photon photoionization reflectron time-of-flight mass spectrometry, the synthesis of hydroxylamine (NH 2 OH), water (H 2 O), hydrogen peroxide (H 2 O 2 ), nitrosyl hydride (HNO), and a series of nitrogen oxides (NO, N 2 O, NO 2 , N 2 O 2 , N 2 O 3 ) was evident. The synthetic pathway of the newly formed species, along with their rate constants, is discussed exploiting the kinetic fitting of the coupled differential equations representing the decomposition steps in the irradiated ice mixtures. Our studies suggest the hydroxylamine is likely formed through an insertion mechanism of suprathermal oxygen into the nitrogen-hydrogen bond of ammonia at such low temperatures. An isotope-labeled experiment examining the electron-irradiated D3-ammonia-oxygen (ND 3 -O 2 ) ices was also conducted, which confirmed our findings. This study provides clear, concise evidence of the formation of hydroxylamine by irradiation of interstellar analogue ices and can help explain the question how potential precursors to complex biorelevant molecules may form in the interstellar medium.

  11. Low temperature irradiation effects on plastic deformation in BCC metals

    International Nuclear Information System (INIS)

    Aono, Yasuhisa


    Low temperature electron beam experiment was carried out on high purity iron and molybdenum single crystals, and its effect on the plastic deformation was examined. As the characteristics of the irradiated iron below 77 K, remarkable softening occurred in all orientations. This phenomenon is based on the interaction of self interstitial atoms and screw dislocations, and the other features such as the absorption of interstitial atoms into screw dislocations and the slip on maximum shearing stress planes were shown. On the other hand, the aggregate of interstitial atoms formed by annealing showed the different plastic characteristics from those of interstitial atoms, and gave the results corresponding to respective stages of the electric resistance recovery curves. Regarding molybdenum, the transfer of its self interstitial atoms is near 40 K, therefore at 77 K, cluster is formed, and it largely affects abnormal slip, which is one of the features of the plasticity of molybdenum. The peculiar dependence of the yield stress on the crystalline orientation was shown. The property of the interaction of the aggregate of interstitial atoms formed and grown by the annealing from 77 K to 500 K with dislocations corresponded to the information of defects obtained by the X-ray research of Maeta, and the similarity to the aggregate of iron was observed. (Kako, I.)

  12. Collective excitations and low temperature transport properties of bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Chudzinski, Piotr; Giamarchi, Thierry [DPMC-MaNEP, University of Geneva (Switzerland)


    We examine the influence of collective excitations on several transport coefficients (conductivity, magneto-optical conductivity, Nernst effect) for semimetal, bismuth. A longstanding problem of the transport coefficients in this material is the fact that their amplitude and temperature dependences do not obey naive Fermi liquid expectations. For the conductivity, we show that at high temperatures Baber scattering is able to explain quantitatively the DC resistivity experiments, while at low temperatures many-body effects need to be introduced to explain qualitative deviations from the standard T{sup 2} behavior. An atypical feature in magneto-optical conductivity is predicted. The Nernst effect in bismuth was recently the subject of several contradictory theoretical studies. We show that a plasmon physics allows to get a coherent picture and leads to very large values of the Nernst signal. We use two complementary methods- Feynmann diagrams and field theory (Hubbard-Stratonovich transformation). These methods, which go beyond the standard RPA study, allow to set a limit to the validity of our model and to make contact with the other family of semimetals, 1T-TiSe{sub 2}, also subject of recent experimental interest. To complete the discussion of semimetals, we also study the case of graphite.

  13. Low temperature heat capacity of scandium and alloys of scandium

    International Nuclear Information System (INIS)

    Tsang, T.W.E.


    The heat capacity of three electrotransport purified scandium samples has been measured from 1 to 20 0 K. The resultant electronic specific heat constant and Debye temperature are 10.337 +- 0.015 mJ/gm-atom K 2 and 346.7 +- 0.8 0 K respectively, and these values are believed to be truly representative of intrinsic scandium. Alloying studies have also been carried out to investigate the band structure of scandium based on the rigid band model, with zirconium to raise the electron concentration and magnesium to lower it. The results are then compared to the theoretical band structure calculations. Low temperature heat capacity measurements have also been made on some dilute Sc-Fe alloys. An anomaly is observed in the C/T vs. T 2 plot, but the C vs. T curve shows no evidence of magnetic ordering down to 1 0 K, and electrical resistance measurement from 4 to 0.3 0 K also indicates that no magnetic ordering took place

  14. Surface-modified low-temperature solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Beom; Holme, Timothy P. [Department of Mechanical Engineering, Stanford University, Stanford, CA 94305 (United States); Guer, Turgut M. [Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 (United States); Prinz, Fritz B. [Department of Mechanical Engineering, Stanford University, Stanford, CA 94305 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 (United States)


    This paper reports both experimental and theoretical results of the role of surface modification on the oxygen reduction reaction in low-temperature solid oxide fuel cells (LT-SOFC). Epitaxial ultrathin films of yttria-doped ceria (YDC) cathode interlayers (<10-130 nm) are grown by pulsed laser deposition (PLD) on single-crystalline YSZ(100). Fuel cell current-voltage measurements and electrochemical impedance spectroscopy are performed in the temperature range of 350 C {approx} 450 C. Quantum mechanical simulations of oxygen incorporation energetics support the experimental results and indicate a low activation energy of only 0.07 eV for YDC, while the incorporation reaction on YSZ is activated by a significantly higher energy barrier of 0.38 eV. Due to enhanced oxygen incorporation at the modified Pt/YDC interface, the cathodic interface resistance is reduced by two-fold, while fuel cell performance shows more than a two-fold enhancement with the addition of an ultrathin YDC interlayer at the cathode side of an SOFC element. The results of this study open up opportunities for improving cell performance, particularly of LT-SOFCs by adopting surface modification of YSZ surface with catalytically superior, ultrathin cathodic interlayers. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Rock swelling during shaft construction caused by low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Demich, L.M.; Kozel, A.M.; Kostyrkin, A.A.; Koldobskii, Yu.A.


    This paper Discusses effects of rock swelling during shaft sinking using rock freezing. A coal mine shaft is sunk up to a depth of 314.8m. The average temperature of sedimentary rocks amounts to 30.5 C. A zone 17.5m in diameter is frozen by 63 freezing pipes. Temperature of freezing mixture amounts to minus 30 C. Location of boreholes and control boreholes as well as fluctuating dimensions of frozen zone are shown in 2 schemes. Rock swelling caused by expansion of water in pores and fissures up to a depth of 135 m is analyzed. Liner deformations reach 30 mm. The most intensive deformations occur in aleurolite zone, with moisture content up to 22.4%. The maximum load which acts on liners amounts to 2,773 kPa. Deformed liners are reinforced by roof bolting and wire net. Negative effects of deformation of monolithic concrete are stressed. It is suggested that when using rock freezing in shaft sinking in porous rock bearing strata rock expansion caused by low temperature should be considered in calculations. Using yielding materials in zones exposed to the highest deformations is recommended. (3 refs.) (In Russian)

  16. Ulta-Low Temperature Properties of Amorphous and Glassy Materials

    Energy Technology Data Exchange (ETDEWEB)

    Douglas D. Osheroff


    During the grant period we made detailed studies of the dynamics of two level tunneling systems in glasses at very low temperature and by the application of AC and DC electric fields. Models have been developed that now account for both the formation and subsequent breaking of resonant tunneling pairs, and strongly bound pairs in a swept electric field. Perhaps most importantly, we saw a critical field in the polymeric glass Mylar, beyond which recovery following the application of a strong electric field is substantially modified from the predictions of current models. It was essential during the final grant period to see how general these new properties were by testing for them in a new and broader set of glasses. At the same time, the discovery that tunneling systems with nuclei possessing electric quadrupole moments that couple the TS behavior to magnetic fields was studied in this laboratory, using some of the probes that we alone employ. Finally, we were developing our own dielectric pulsed echo system, operating for the first time at the low energy splittings and hence temperatures at which interactions between TS are important. We combined this technique with the sudden application of both electric and strain fields to better understand the dynamics of the response of TS in glasses on a much shorter time scale than is possible with our established probes.

  17. Low Temperature Plasma Kills SCaBER Cancer Cells (United States)

    Barekzi, Nazir; van Way, Lucas; Laroussi, Mounir


    Squamous cell carcinoma of the bladder is a rare type of bladder cancer that forms as a result of chronic irritation of the epithelial lining of the bladder. The cell line used in this study is SCaBER (ATCC® HTB-3™) derived from squamous cell carcinoma of the human urinary bladder. Current treatments of bladder cancer include surgery, radiation and chemotherapy. However, the cost of these treatments, the potential toxicity of the chemotherapeutic agents and the systemic side-effects warrant an alternative to current cancer treatment. This paper represents preliminary studies to determine the effects of biologically tolerant plasma (BTP) on a cell line of human bladder cancer cells. Previous work by our group using the plasma pencil revealed the efficacy of BTP on leukemia cells suspended in solution. Based on these earlier findings we hypothesized that the plasma exposure would elicit a similar programmed cell death in the SCaBER cells. Trypan blue exclusion and MTT assays revealed the cell killing after exposure to BTP. Our study indicates that low temperature plasma generated by ionizing helium gas and the reactive species may be a suitable and safe alternative for cancer therapy.

  18. Development of UItra-Low Temperature Motor Controllers: Ultra Low Temperatures Evaluation and Characterization of Semiconductor Technologies For The Next Generation Space Telescope (United States)

    Elbuluk, Malik E.


    Electronics designed for low temperature operation will result in more efficient systems than room temperature. This improvement is a result of better electronic, electrical, and thermal properties of materials at low temperatures. In particular, the performance of certain semiconductor devices improves with decreasing temperature down to ultra-low temperature (-273 'C). The Low Temperature Electronics Program at the NASA Glenn Research Center focuses on research and development of electrical components and systems suitable for applications in deep space missions. Research is being conducted on devices and systems for use down to liquid helium temperatures (-273 'C). Some of the components that are being characterized include semiconductor switching devices, resistors, magnetics, and capacitors. The work performed this summer has focused on the evaluation of silicon-, silicon-germanium- and gallium-Arsenide-based (GaAs) bipolar, MOS and CMOS discrete components and integrated circuits (ICs), from room temperature (23 'C) down to ultra low temperatures (-263 'C).

  19. Low Temperature Regolith Bricks for In-Situ Structural Material (United States)

    Grossman, Kevin; Sakthivel, Tamil S.; Mantovani, James; Seal, Sudipta


    Current technology for producing in-situ structural materials on future missions to Mars or the moon relies heavily on energy-intensive sintering processes to produce solid bricks from regolith. This process requires heating the material up to temperatures in excess of 1000 C and results in solid regolith pieces with compressive strengths in the range of 14000 to 28000 psi, but are heavily dependent on the porosity of the final material and are brittle. This method is currently preferred over a low temperature cementation process to prevent consumption of precious water and other non-renewable materials. A high strength structural material with low energy requirements is still needed for future colonization of other planets. To fulfill these requirements, a nano-functionalization process has been developed to produce structural bricks from regolith simulant and shows promising mechanical strength results. Functionalization of granular silicate particles into alkoxides using a simple low temperature chemical process produces a high surface area zeolite particles that are held together via inter-particle oxygen bonding. Addition of water in the resulting zeolite particles produces a sol-gel reaction called "inorganic polymerization" which gives a strong solid material after a curing process at 60 C. The aqueous solution by-product of the reaction is currently being investigated for its reusability; an essential component of any ISRU technology. For this study, two batches of regolith bricks are synthesized from JSC-1A; the first batch from fresh solvents and chemicals, the second batch made from the water solution by-product of the first batch. This is done to determine the feasibility of recycling necessary components of the synthesis process, mainly water. Characterization including BET surface area, SEM, and EDS has been done on the regolith bricks as well as the constituent particles,. The specific surface area of 17.53 sq m/g (average) of the granular regolith

  20. Conversion of medium and low temperature heat to power (United States)

    Fischer, Johann; Wendland, Martin; Lai, Ngoc Anh


    Presently most electricity is produced in power plants which use high temperature heat supplied by coal, oil, gas or nuclear fission and Clausius-Rankine cycles (CRC) with water as working fluid (WF). On the other hand, geo-, solar-, ocean-, and biogenic-heat have medium and low temperatures. At these temperatures, however, the use of other WF and/or other cycles can yield higher efficiencies than those of the water-CRC. For an assessment of the efficiency we model systems which include the heat transfer to and from the WF and the cycle. Optimization criterion is the exergy efficiency defined as the ratio of the net power output to the incoming exergy flow of the heat carrier. First, for a better understanding we discuss some thermodynamic properties of the WFs: 1) the critical point parameters, 2) the shape of the vapour- liquid coexistence curve in the temperature vs entropy (T,s)-diagram which may be either bell-shaped or overhanging [1,2], and 3) the shape of sub- and supercritical isobars for pure fluids and fluid mixtures. Second, we show that the problems of a CRC with water at lower temperatures are 1) the shape of the T,s-diagram and 2) the exergy loss during heat transfer to the WF. The first problem can be overcome by using an organic working fluid in the CRC which then is called organic Rankine cycle (ORC). The second problem is reduced by supercritical organic Rankine cycles (sORC) [1,2], trilateral cycles (TLC) and the more general power-flash cycles (PFC) [2], and organic flash cycles (OFC) [3]. Next, selected results for systems with the above mentioned cycles will be presented. The heat carrier inlet temperatures THC range from 120°C to 350°C.The pure working fluids are water, refrigerants, alkanes, aromates and siloxanes and have to be selected to match with THC. It is found that TLC with water have the highest efficiencies but show very large volume flows at lower temperatures. Moreover, expansion machines for TLC and PFC are still under

  1. Low Temperature and Modified Atmosphere: Hurdles for Antibiotic Resistance Transfer? (United States)

    Van Meervenne, Eva; Van Coillie, Els; Van Weyenberg, Stephanie; Boon, Nico; Herman, Lieve; Devlieghere, Frank


    Food is an important dissemination route for antibiotic-resistant bacteria. Factors used during food production and preservation may contribute to the transfer of antibiotic resistance genes, but research on this subject is scarce. In this study, the effect of temperature (7 to 37°C) and modified atmosphere packaging (air, 50% CO2-50% N2, and 100% N2) on antibiotic resistance transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes was evaluated. Filter mating was performed on nonselective agar plates with high-density inocula. A more realistic setup was created by performing modified atmosphere experiments on cooked ham using high-density and low-density inocula. Plasmid transfer was observed between 10 and 37°C, with plasmid transfer also observed at 7°C during a prolonged incubation period. When high-density inocula were used, transconjugants were detected, both on agar plates and cooked ham, under the three atmospheres (air, 50% CO2-50% N2, and 100% N2) at 7°C. This yielded a median transfer ratio (number of transconjugants/number of recipients) with an order of magnitude of 10(-4) to 10(-6). With low-density inocula, transfer was only detected under the 100% N2 atmosphere after 10-day incubation at 7°C, yielding a transfer ratio of 10(-5). Under this condition, the highest bacterial density was obtained. The results indicate that low temperature and modified atmosphere packaging, two important hurdles in the food industry, do not necessarily prevent plasmid transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes.

  2. Low-temperature susceptibility of concentrated magnetic fluids (United States)

    Pshenichnikov, Alexander F.; Lebedev, Alexander V.


    The initial susceptibility of concentrated magnetic fluids (ferrocolloids) has been experimentally investigated at low temperatures. The results obtained indicate that the interparticle dipole-dipole interactions can increase the susceptibility by several times as compared to the Langevin value. It is shown that good agreement between recent theoretical models and experimental observations can be achieved by introducing a correction for coefficients in the series expansion of susceptibility in powers of density and aggregation parameter. A modified equation for equilibrium susceptibility is offered to sum over corrections made by Kalikmanov (Statistical Physics of Fluids, Springer-Verlag, Berlin, 2001) and by B. Huke and M. Lücke (Phys. Rev. E 67, 051403, 2003). The equation gives good quantitative agreement with the experimental data in the wide range of temperature and magnetic particles concentration. It has been found that in some cases the magnetic fluid solidification occurs at temperature several tens of kelvins higher than the crystallization temperature of the carrier liquid. The solidification temperature of magnetic fluids is independent of particle concentration (i.e., magneto-dipole interparticle interactions) and dependent on the surfactant type and carrier liquid. This finding allows us to suggest that molecular interactions and generation of some large-scale structure from colloidal particles in magnetic fluids are responsible for magnetic fluid solidification. If the magnetic fluid contains the particles with the Brownian relaxation mechanism of the magnetic moment, the solidification manifests itself as the peak on the "susceptibility-temperature" curve. This fact proves the dynamic nature of the observed peak: it arises from blocking the Brownian mechanism of the magnetization relaxation.

  3. Interaction of Low Temperature Plasmas with Prokaryotic and Eukaryotic Cells (United States)

    Laroussi, Mounir


    Due to promising possibilities for their use in medical applications such as wound healing, surface modification of biocompatible materials, and the sterilization of reusable heat-sensitive medical instruments, low temperature plasmas and plasma jets are making big strides as a technology that can potentially be used in medicine^1-2. At this stage of research, fundamental questions about the effects of plasma on prokaryotic and eukaryotic cells are still not completely answered. An in-depth understanding of the pathway whereby cold plasma interact with biological cells is necessary before real applications can emerge. In this paper, first an overview of non-equilibrium plasma sources (both low and high pressures) will be presented. Secondly, the effects of plasma on bacterial cells will be discussed. Here, the roles of the various plasma agents in the inactivation process will be outlined. In particular, the effects of UV and that of various reactive species (O3, O, OH) are highlighted. Thirdly, preliminary findings on the effects of plasma on few types of eukaryotic cells will be presented. How plasma affects eukaryotic cells, such as mammalian cells, is very important in applications where the viability/preservation of the cells could be an issue (such as in wound treatment). Another interesting aspect is the triggering of apoptosis (programmed cell death). Some investigators have claimed that plasma is able to induce apoptosis in some types of cancer cells. If successfully replicated, this can open up a novel method of cancer treatment. In this talk however, I will briefly focus more on the wound healing potential of cold plasmas. ^1E. A. Blakely, K. A. Bjornstad, J. E. Galvin, O. R. Monteiro, and I. G. Brown, ``Selective Neuron Growth on Ion Implanted and Plasma Deposited Surfaces'', In Proc. IEEE Int. Conf. Plasma Sci., (2002), p. 253. ^2M. Laroussi, ``Non-thermal Decontamination of Biological Media by Atmospheric Pressure Plasmas: Review, Analysis, and

  4. Low temperature sintering of fluorapatite glass-ceramics. (United States)

    Denry, Isabelle; Holloway, Julie A


    Fluorapatite glass-ceramics have been shown to be excellent candidates as scaffold materials for bone grafts, however, scaffold production by sintering is hindered by concurrent crystallization of the glass. Objective, our goal was to investigate the effect of Ca/Al ratio on the sintering behavior of Nb-doped fluorapatite-based glasses in the SiO2-Al2O3-P2O5-MgO-Na2O-K2O-CaO-CaF2 system. Methods, glass compositions with Ca/Al ratio of 1 (A), 2 (B), 4 (C) and 19 (D) were prepared by twice melting at 1525°C for 3h. Glasses were either cast as cylindrical ingots or ground into powders. Disk-shaped specimens were prepared by either sectioning from the ingots or powder-compacting in a mold, followed by heat treatment at temperatures ranging between 700 and 1050°C for 1h. The density was measured on both sintered specimens and heat treated discs as controls. The degree of sintering was determined from these measurements. Results and Significance XRD showed that fluorapatite crystallized in all glass-ceramics. A high degree of sintering was achieved at 775°C for glass-ceramic D (98.99±0.04%), and 900°C for glass-ceramic C (91.31±0.10). Glass-ceramics A or B were only partially sintered at 1000°C (63.6±0.8% and 74.1±1.5%, respectively). SEM revealed a unique microstructure of micron-sized spherulitic fluorapatite crystals in glass-ceramics C and D. Increasing the Ca/Al ratio promoted low temperature sintering of fluorapatite glass-ceramics, which are traditionally difficult to sinter. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  5. Effect of low temperature baking on niobium cavities

    Energy Technology Data Exchange (ETDEWEB)

    Peter Kneisel; Ganapati Myneni; William Lanford; Gianluigi Ciovati


    A low temperature (100 C-150 C) ''in situ'' baking under ultra-high vacuum has been successfully applied as final preparation of niobium RF cavities by several laboratories over the last few years. The benefits reported consist mainly of an improvement of the cavity quality factor and a recovery from the so-called ''Q-drop'' without field emission at high field. A series of experiments with a CEBAF single cell cavity have been carried out at Jefferson Lab to carefully investigate the effect of baking at progressively higher temperatures for a fixed time on all the relevant material parameters. Measurements of the cavity quality factor in the temperature range 1.37K-280K and resonant frequency shift between 6K-9.3K provide information about the surface resistance, energy gap, penetration depth and mean free path. The experimental data have been analyzed with the complete BCS theory of superconductivity using a modified version of the computer code originally written by J. Halbritter [1] . Small niobium samples inserted in the cavity during its surface preparation were analyzed with respect to their hydrogen content with a Nuclear Reaction Analysis (NRA). The single cell cavity has been tested at three different temperatures before and after baking to gain some insight on thermal conductivity and Kapitza resistance and the data are compared with different models. This paper describes the results from these experiments and comments on the existing models to explain the effect of baking on the performance of niobium RF cavities.

  6. Transcriptional responses of olive flounder (Paralichthys olivaceus to low temperature.

    Directory of Open Access Journals (Sweden)

    Jinwei Hu

    Full Text Available The olive flounder (Paralichthys olivaceus is an economically important flatfish in marine aquaculture with a broad thermal tolerance ranging from 14 to 23°C. Cold-tolerant flounder that can survive during the winter season at a temperature of less than 14°C might facilitate the understanding of the mechanisms underlying the response to cold stress. In this study, the transcriptional response of flounder to cold stress (0.7±0.05°C was characterized using RNA sequencing. Transcriptome sequencing was performed using the Illumina MiSeq platform for the cold-tolerant (CT group, which survived under the cold stress; the cold-sensitive (CS group, which could barely survive at the low temperature; and control group, which was not subjected to cold treatment. In all, 29,021 unigenes were generated. Compared with the unigene expression profile of the control group, 410 unigenes were up-regulated and 255 unigenes were down-regulated in the CT group, whereas 593 unigenes were up-regulated and 289 unigenes were down-regulated in the CS group. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed that signal transduction, lipid metabolism, digestive system, and signaling molecules and interaction were the most highly enriched pathways for the genes that were differentially expressed under cold stress. All these pathways could be assigned to the following four biological functions for flounder that can survive under cold stress: signal response to cold stress, cell repair/regeneration, energy production, and cell membrane construction and fluidity.

  7. Low temperature aluminum nitride thin films for sensory applications

    Energy Technology Data Exchange (ETDEWEB)

    Yarar, E.; Zamponi, C.; Piorra, A.; Quandt, E., E-mail: [Institute for Materials Science, Chair for Inorganic Functional Materials, Kiel University, D-24143 Kiel (Germany); Hrkac, V.; Kienle, L. [Institute for Materials Science, Chair for Synthesis and Real Structure, Kiel University, D-24143 Kiel (Germany)


    A low-temperature sputter deposition process for the synthesis of aluminum nitride (AlN) thin films that is attractive for applications with a limited temperature budget is presented. Influence of the reactive gas concentration, plasma treatment of the nucleation surface and film thickness on the microstructural, piezoelectric and dielectric properties of AlN is investigated. An improved crystal quality with respect to the increased film thickness was observed; where full width at half maximum (FWHM) of the AlN films decreased from 2.88 ± 0.16° down to 1.25 ± 0.07° and the effective longitudinal piezoelectric coefficient (d{sub 33,f}) increased from 2.30 ± 0.32 pm/V up to 5.57 ± 0.34 pm/V for film thicknesses in the range of 30 nm to 2 μm. Dielectric loss angle (tan δ) decreased from 0.626% ± 0.005% to 0.025% ± 0.011% for the same thickness range. The average relative permittivity (ε{sub r}) was calculated as 10.4 ± 0.05. An almost constant transversal piezoelectric coefficient (|e{sub 31,f}|) of 1.39 ± 0.01 C/m{sup 2} was measured for samples in the range of 0.5 μm to 2 μm. Transmission electron microscopy (TEM) investigations performed on thin (100 nm) and thick (1.6 μm) films revealed an (002) oriented AlN nucleation and growth starting directly from the AlN-Pt interface independent of the film thickness and exhibit comparable quality with the state-of-the-art AlN thin films sputtered at much higher substrate temperatures.


    Directory of Open Access Journals (Sweden)

    Padhraig eMadden


    Full Text Available The effect of sulphate addition on the stability of, and microbial community behaviour in, low-temperature anaerobic expanded granular sludge bed-based bioreactors was investigated at 15°C. Efficient bioreactor performance was observed, with chemical oxygen demand removal efficiencies of >90%, and a mean SO42- removal rate of 98.3%. In situ methanogensis appeared unaffected at a COD:SO42- influent ratio of 8:1, and subsequently of 3:1, and was impacted marginally only when the COD: SO42- ratio was 1:2. . Specific methanogenic activity assays indicated a complex set of interactions between sulphate-reducing bacteria (SRB, methanogens and homoacetogenic bacteria. SO42- addition resulted in predominantly acetoclastic, rather than hydrogenotrophic, methanogenesis until >600 days of SO42--influenced bioreactor operation. Temporal microbial community development was monitored by denaturation gradient gel electrophoresis (DGGE of 16S rRNA genes. Fluorescence in situ hybridisations (FISH, qPCR and microsensor analysis were combined to investigate the distribution of microbial groups, and particularly SRB and methanogens, along the structure of granular biofilms. qPCR data indicated that sulphidogenic genes were present in methanogenic and sulfidogenic biofilms, indicating the potential for sulphate reduction even in bioreactors not exposed to SO42-. Although the architecture of methanogenic and sulphidogenic granules was similar, indicating the presence of SRB even in methanogenic systems, FISH with rRNA targets found that the SRB were more abundant in the sulphidogenic biofilms. Methanosaeta species were the predominant, keystone members of the archaeal community, with the complete absence of the Methanosarcina species in the experimental bioreactor by trial conclusion. Microsensor data suggested the ordered distribution of sulphate reduction and sulphide accumulation, even in methanogenic granules.

  9. Low temperature sintering of fluorapatite glass-ceramics (United States)

    Denry, Isabelle; Holloway, Julie A.


    Fluorapatite glass-ceramics have been shown to be excellent candidates as scaffold materials for bone grafts, however, scaffold production by sintering is hindered by concurrent crystallization of the glass. Our goal was to investigate the effect of Ca/Al ratio on the sintering behavior of Nb-doped fluorapatite-based glasses in the SiO2-Al2O3-P2O5-MgO-Na2O-K2O-CaO-CaF2 system. Glass compositions with Ca/Al ratio of 1 (A), 2 (B), 4 (C) and 19 (D) were prepared by twice melting at 1525°C for 3h. Glasses were either cast as cylindrical ingots or ground into powders. Disc-shaped specimens were prepared by either sectioning from the ingots or powder-compacting in a mold, followed by heat treatment at temperatures ranging between 700 and 1050°C for 1h. The density was measured on both sintered specimens and heat treated discs as controls. The degree of sintering was determined from these measurements. XRD showed that fluorapatite crystallized in all glass-ceramics. A high degree of sintering was achieved at 775°C for glass-ceramic D (98.99±0.04%), and 900°C for glass-ceramic C (91.31±0.10). Glass-ceramics A or B were only partially sintered at 1000°C (63.6±0.8% and 74.1±1.5%, respectively). SEM revealed a unique microstructure of micron-sized spherulitic fluorapatite crystals in glass-ceramics C and D. Increasing the Ca/Al ratio promoted low temperature sintering of fluorapatite glass-ceramics, which are traditionally difficult to sinter. PMID:24252652

  10. Low Temperature Combustion Demonstrator for High Efficiency Clean Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda, William de


    The project which extended from November 2005 to May of 2010 demonstrated the application of Low Temperature Combustion (LTC) with engine out NOx levels of 0.2 g/bhp-hr throughout the program target load of 12.6bar BMEP. The project showed that the range of loads could be extended to 16.5bar BMEP, therefore matching the reference lug line of the base 2007 MY Navistar 6.4L V8 engine. Results showed that the application of LTC provided a dramatic improvement over engine out emissions when compared to the base engine. Furthermore LTC improved thermal efficiency by over 5% from the base production engine when using the steady state 13 mode composite test as a benchmark. The key enablers included improvements in the air, fuel injection, and cooling systems made in Phases I and II. The outcome was the product of a careful integration of each component under an intelligent control system. The engine hardware provided the conditions to support LTC and the controller provided the necessary robustness for a stable combustion. Phase III provided a detailed account on the injection strategy used to meet the high load requirements. During this phase, the control strategy was implemented in a production automotive grade ECU to perform cycle-by-cycle combustion feedback on each of the engine cylinders. The control interacted on a cycle base with the injection system and with the Turbo-EGR systems according to their respective time constants. The result was a unique system that could, first, help optimize the combustion system and maintain high efficiency, and secondly, extend the steady state results to the transient mode of operation. The engine was upgraded in Phase IV with a Variable Valve Actuation system and a hybrid EGR loop. The impact of the more versatile EGR loop did not provide significant advantages, however the application of VVA proved to be an enabler to further extend the operation of LTC and gain considerable benefits in fuel economy and soot reduction. Finally

  11. Defect studies in low-temperature-grown GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Bliss, David Emory [Univ. of California, Berkeley, CA (United States)


    High content of excess As is incorporated in GaAs grown by low-temperature molecular-beam-epitaxy (LTMBE). The excess As exists primarily as As antisite defects AsGa and a lesser extent of gallium vacancies VGa. The neutral AsGa-related defects were measured by infrared absorption at 1μm. Gallium vacancies, VGa, was investigated by slow positron annihilation. Dependence of defect contents on doping was studied by Si and Be dopants. No free carriers are generated by n-type or p-type doping up to 1019 cm-3 Si or Be. Raman data indicate Be occupies Ga substitutional sites but Si atom is not substitutional. Si induces more AsGa in the layer. As AsGa increases, photoquenchable AsGa decreases. Fraction of photoquenchable defects correlates to defects within 3 nearest neighbor separations disrupting the metastability. Annealing reduces neutral AsGa content around 500C, similar to irradiation damaged and plastically deformed GaAs, as opposed to bulk grown GaAs in which AsGa-related defects are stable up to 1100C. The lower temperature defect removal is due to VGa enhanced diffusion of AsGa to As precipitates. The supersaturated VGa and also decreases during annealing. Annealing kinetics for AsGa-related defects gives 2.0 ± 0.3 eV and 1.5 ± 0.3 eV migration enthalpies for the AsGa and VGa. This represents the difference between Ga and As atoms hopping into the vacancy. The non-photoquenchable AsGa-related defects anneal with an activation energy of 1.1 ± 0.3eV. Be acceptors can be activated by 800C annealing. Temperature difference between defect annealing and Be activation formation of AsGa-BeGa pairs. Si donors can only be partially activated.

  12. Defect studies in low-temperature-grown GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Bliss, D.E.


    High content of excess As is incorporated in GaAs grown by low-temperature molecular-beam-epitaxy (LTMBE). The excess As exists primarily as As antisite defects AsGa and a lesser extent of gallium vacancies V[sub Ga]. The neutral AsGa-related defects were measured by infrared absorption at 1[mu]m. Gallium vacancies, V[sub Ga], was investigated by slow positron annihilation. Dependence of defect contents on doping was studied by Si and Be dopants. No free carriers are generated by n-type or p-type doping up to 10[sup 19] cm[sup [minus]3] Si or Be. Raman data indicate Be occupies Ga substitutional sites but Si atom is not substitutional. Si induces more As[sub Ga] in the layer. As As[sub Ga] increases, photoquenchable As[sub Ga] decreases. Fraction of photoquenchable defects correlates to defects within 3 nearest neighbor separations disrupting the metastability. Annealing reduces neutral As[sub Ga] content around 500C, similar to irradiation damaged and plastically deformed Ga[sub As], as opposed to bulk grown GaAs in which As[sub Ga]-related defects are stable up to 1100C. The lower temperature defect removal is due to V[sub Ga] enhanced diffusion of As[sub Ga] to As precipitates. The supersaturated V[sub GA] and also decreases during annealing. Annealing kinetics for As[sub Ga]-related defects gives 2.0 [plus minus] 0.3 eV and 1.5 [plus minus] 0.3 eV migration enthalpies for the As[sub Ga] and V[sub Ga]. This represents the difference between Ga and As atoms hopping into the vacancy. The non-photoquenchable As[sub Ga]-related defects anneal with an activation energy of 1.1 [plus minus] 0.3eV. Be acceptors can be activated by 800C annealing. Temperature difference between defect annealing and Be activation formation of As[sub Ga]-Be[sub Ga] pairs. Si donors can only be partially activated.

  13. Determination of viability of preserved skin in low temperature

    International Nuclear Information System (INIS)

    Yang Hong Chang; Hao Zheng Ming; Zao Xiao Chun


    preservation temperature was important and the lower the better as the survival rate was high. Also results showed that the skin could be stored for a long period of time. There are still many necessary conditions and influential factors for preservation of skin in low temperature. However, no discussion on it was made in this experiment

  14. Global unitary fixing and matrix-valued correlations in matrix models

    International Nuclear Information System (INIS)

    Adler, Stephen L.; Horwitz, Lawrence P.


    We consider the partition function for a matrix model with a global unitary invariant energy function. We show that the averages over the partition function of global unitary invariant trace polynomials of the matrix variables are the same when calculated with any choice of a global unitary fixing, while averages of such polynomials without a trace define matrix-valued correlation functions, that depend on the choice of unitary fixing. The unitary fixing is formulated within the standard Faddeev-Popov framework, in which the squared Vandermonde determinant emerges as a factor of the complete Faddeev-Popov determinant. We give the ghost representation for the FP determinant, and the corresponding BRST invariance of the unitary-fixed partition function. The formalism is relevant for deriving Ward identities obeyed by matrix-valued correlation functions

  15. Non-unitary neutrino propagation from neutrino decay

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, Jeffrey M., E-mail: [Northwestern University, Department of Physics & Astronomy, 2145 Sheridan Road, Evanston, IL 60208 (United States); Gouvêa, André de; Hernández, Daniel [Northwestern University, Department of Physics & Astronomy, 2145 Sheridan Road, Evanston, IL 60208 (United States); Oliveira, Roberto L.N. [Northwestern University, Department of Physics & Astronomy, 2145 Sheridan Road, Evanston, IL 60208 (United States); Instituto de Física Gleb Wataghin Universidade Estadual de Campinas, UNICAMP 13083-970, Campinas, São Paulo (Brazil)


    Neutrino propagation in space-time is not constrained to be unitary if very light states – lighter than the active neutrinos – exist into which neutrinos may decay. If this is the case, neutrino flavor-change is governed by a handful of extra mixing and “oscillation” parameters, including new sources of CP-invariance violation. We compute the transition probabilities in the two- and three-flavor scenarios and discuss the different phenomenological consequences of the new physics. These are qualitatively different from other sources of unitarity violation discussed in the literature.

  16. Non-unitary neutrino propagation from neutrino decay

    International Nuclear Information System (INIS)

    Berryman, Jeffrey M.; Gouvêa, André de; Hernández, Daniel; Oliveira, Roberto L.N.


    Neutrino propagation in space-time is not constrained to be unitary if very light states – lighter than the active neutrinos – exist into which neutrinos may decay. If this is the case, neutrino flavor-change is governed by a handful of extra mixing and “oscillation” parameters, including new sources of CP-invariance violation. We compute the transition probabilities in the two- and three-flavor scenarios and discuss the different phenomenological consequences of the new physics. These are qualitatively different from other sources of unitarity violation discussed in the literature

  17. A Unitary-Transformative Nursing Science: From Angst to Appreciation. (United States)

    Cowling, W Richard


    The discord within nursing regarding the definition of nursing science has created great angst, particularly for those who view nursing science as a body of knowledge derived from theories specific to its unique concerns. The purpose of this brief article is to suggest a perspective and process grounded in appreciation of wholeness that may offer a way forward for proponents of a unitary-transformative nursing science that transcends the discord. This way forward is guided by principles of fostering dissent without contempt, generating a well-imagined future, and garnering appreciatively inspired action for change.

  18. Introduction to orthogonal, symplectic and unitary representations of finite groups

    CERN Document Server

    Riehm, Carl R


    Orthogonal, symplectic and unitary representations of finite groups lie at the crossroads of two more traditional subjects of mathematics-linear representations of finite groups, and the theory of quadratic, skew symmetric and Hermitian forms-and thus inherit some of the characteristics of both. This book is written as an introduction to the subject and not as an encyclopaedic reference text. The principal goal is an exposition of the known results on the equivalence theory, and related matters such as the Witt and Witt-Grothendieck groups, over the "classical" fields-algebraically closed, rea

  19. Local unitary representation of braids and N-qubit entanglements (United States)

    Yu, Li-Wei


    In this paper, by utilizing the idea of stabilizer codes, we give some relationships between one local unitary representation of braid group in N-qubit tensor space and the corresponding entanglement properties of the N-qubit pure state |Ψ >, where the N-qubit state |Ψ > is obtained by applying the braiding operation on the natural basis. Specifically, we show that the separability of |Ψ > =B|0> ^{⊗ N} is closely related to the diagrammatic version of the braid operator B. This may provide us more insights about the topological entanglement and quantum entanglement.

  20. Deformations of polyhedra and polygons by the unitary group

    International Nuclear Information System (INIS)

    Livine, Etera R.


    We introduce the set of framed (convex) polyhedra with N faces as the symplectic quotient C 2N //SU(2). A framed polyhedron is then parametrized by N spinors living in C 2 satisfying suitable closure constraints and defines a usual convex polyhedron plus extra U(1) phases attached to each face. We show that there is a natural action of the unitary group U(N) on this phase space, which changes the shape of faces and allows to map any (framed) polyhedron onto any other with the same total (boundary) area. This identifies the space of framed polyhedra to the Grassmannian space U(N)/ (SU(2)×U(N−2)). We show how to write averages of geometrical observables (polynomials in the faces' area and the angles between them) over the ensemble of polyhedra (distributed uniformly with respect to the Haar measure on U(N)) as polynomial integrals over the unitary group and we provide a few methods to compute these integrals systematically. We also use the Itzykson-Zuber formula from matrix models as the generating function for these averages and correlations. In the quantum case, a canonical quantization of the framed polyhedron phase space leads to the Hilbert space of SU(2) intertwiners (or, in other words, SU(2)-invariant states in tensor products of irreducible representations). The total boundary area as well as the individual face areas are quantized as half-integers (spins), and the Hilbert spaces for fixed total area form irreducible representations of U(N). We define semi-classical coherent intertwiner states peaked on classical framed polyhedra and transforming consistently under U(N) transformations. And we show how the U(N) character formula for unitary transformations is to be considered as an extension of the Itzykson-Zuber to the quantum level and generates the traces of all polynomial observables over the Hilbert space of intertwiners. We finally apply the same formalism to two dimensions and show that classical (convex) polygons can be described in a similar

  1. Multiscale differential phase contrast analysis with a unitary detector

    KAUST Repository

    Lopatin, Sergei


    A new approach to generate differential phase contrast (DPC) images for the visualization and quantification of local magnetic fields in a wide range of modern nano materials is reported. In contrast to conventional DPC methods our technique utilizes the idea of a unitary detector under bright field conditions, making it immediately usable by a majority of modern transmission electron microscopes. The approach is put on test to characterize the local magnetization of cylindrical nanowires and their 3D ordered arrays, revealing high sensitivity of our method in a combination with nanometer-scale spatial resolution.

  2. Low-temperature Stirling Engine for Geothermal Electricity Generation

    Energy Technology Data Exchange (ETDEWEB)

    Stillman, Greg [Cool Energy, Inc., Boulder, CO (United States); Weaver, Samuel P. [Cool Energy, Inc., Boulder, CO (United States)


    Up to 2700 terawatt-hours per year of geothermal electricity generation capacity has been shown to be available within North America, typically with wells drilled into geologically active regions of the earth's crust where this energy is concentrated (Huttrer, 2001). Of this potential, about half is considered to have temperatures high enough for conventional (steam-based) power production, while the other half requires unconventional power conversion approaches, such as organic Rankine cycle systems or Stirling engines. If captured and converted effectively, geothermal power generation could replace up to 100GW of fossil fuel electric power generation, leading to a significant reduction of US power sector emissions. In addition, with the rapid growth of hydro-fracking in oil and gas production, there are smaller-scale distributed power generation opportunities in heated liquids that are co-produced with the main products. Since 2006, Cool Energy, Inc. (CEI) has designed, fabricated and tested four generations of low-temperature (100°C to 300°C) Stirling engine power conversion equipment. The electric power output of these engines has been demonstrated at over 2kWe and over 16% thermal conversion efficiency for an input temperature of 215°C and a rejection temperature of 15°C. Initial pilot units have been shipped to development partners for further testing and validation, and significantly larger engines (20+ kWe) have been shown to be feasible and conceptually designed. Originally intended for waste heat recovery (WHR) applications, these engines are easily adaptable to geothermal heat sources, as the heat supply temperatures are similar. Both the current and the 20+ kWe designs use novel approaches of self-lubricating, low-wear-rate bearing surfaces, non-metallic regenerators, and high-effectiveness heat exchangers. By extending CEI's current 3 kWe SolarHeart® Engine into the tens of kWe range, many additional applications are possible, as one

  3. Low Temperature Plasma for the Treatment of Epithelial Cancer Cells (United States)

    Mohades, Soheila

    Biomedical applications of low temperature plasmas (LTP) may lead to a paradigm shift in treating various diseases by conducting fundamental research on the effects of LTP on cells, tissues, organisms (plants, insects, and microorganisms). This is a rapidly growing interdisciplinary research field that involves engineering, physics, life sciences, and chemistry to find novel solutions for urgent medical needs. Effects of different LTP sources have shown the anti-tumor properties of plasma exposure; however, there are still many unknowns about the interaction of plasma with eukaryotic cells which must be elucidated in order to evaluate the practical potential of plasma in cancer treatment. Plasma, the fourth state of matter, is composed of electrons, ions, reactive molecules (radicals and non-radicals), excited species, radiation, and heat. A sufficient dose (time) of plasma exposure can induce death in cancer cells. The plasma pencil is employed to study the anti-tumor properties of this treatment on epithelial cells. The plasma pencil has been previously used for the inactivation of bacteria, destroying amyloid fibrils, and the killing of various cancer cells. Bladder cancer is the 9th leading cause of cancer. In this dissertation, human urinary bladder tissue with the squamous cell carcinoma disease (SCaBER cells) is treated with LTP utilizing two different approaches: direct plasma exposure and Plasma Activated Media (PAM) as an advancement to the treatment. PAM is produced by exposing a liquid cell culture medium to the plasma pencil. Direct LTP treatment of cancer cells indicates a dose-dependent killing effect at post-treatment times. Similarly, PAM treatment shows an anti-cancer effect by inducing substantial cell death. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) have an important role in the biomedical effects of LTP treatment. This study demonstrates the capability of the plasma pencil to transport ROS/RNS into cell culture media

  4. Organ preservation at low temperature: a physical and biological problem (United States)

    Aussedat, J.; Boutron, P.; Coquilhat, P.; Descotes, J. L.; Faure, G.; Ferrari, M.; Kay, L.; Mazuer, J.; Monod, P.; Odin, J.; Ray, A.


    Before reporting the preliminary results obtained by our group, we first review the main problems to be solved in the preservation of organs at very low temperature, before being transplanted. This cryopreservation is being presently explored in order to increase the preservation tiine of transplants and to contribute to a better control of the donor recipient compatibility. We recall that, for the isolated cells to be preserved at nitrogen liquid temperatures, as now successfully performed at industrial scale, it is necessary to immerse the cells in a solution containing more or less t,oxical additives (so-called cryopro tect ants). Furthermore cooling and warming rates must be specific of each type of cells. We then show that cryo preservation could be extrapolated to whole organs by means of vitrification, the only way to avoid any ice crystallization. This vitrification will be the result of two directions of research, the one on the elaboration of cryoprotective solutions, the least toxic possible, the other on the obtention of high enough and homogeneous cooling and warming rates. After having briefly summarized the state of research on the heart and kidneys of small mammals, we present the first results that we have obtained on perfusion at 4 ^{circ}C and the auto-transplantation of rabbit kidneys, on the toxicity of a new cryoprotectant, 2,3-butanediol, on the heart rate, and on the cooling of experimental models of organs. Avant de présenter les résultats préliminaires obtenus par notre groupe, nous passons d'abord en revue les principaux problèmes à résoudre pour conserver à très basse température des organes en vue de leur transplantation. Cette cryopréservation est une voie de recherche actuellement explorée pour augmenter la durée de conservation des greffons et permettre ainsi de mieux contrôler la compatibilité donneur-receveur. Nous rappelons que la conservation des cellules isolées à la température de l'azote liquide, actuellement

  5. Functional analysis of lipid metabolism genes in wine yeasts during alcoholic fermentation at low temperature


    L?pez-Malo, Mar?a; Garc?a-R?os, Est?fani; Chiva, Rosana; Guillamon, Jos? M.


    Wine produced by low-temperature fermentation is mostly considered to have improved sensory qualities. However few commercial wine strains available on the market are well-adapted to ferment at low temperature (10 – 15°C). The lipid metabolism of Saccharomyces cerevisiae plays a central role in low temperature adaptation. One strategy to modify lipid composition is to alter transcriptional activity by deleting or overexpressing the key genes of lipid metabolism. In a previous study, we identi...

  6. Radiation detection at very low temperature. DRTBT 1991 Aussois - Course collection

    International Nuclear Information System (INIS)

    Salce, B.; Godfrin, H.; Dumoulin, L.; Garoche, Pierre; Pannetier, B.; Equer, B.; Hubert, PH.; Urbina, C.; Lamarre, J.M.; Brison, J.P.; Lesueur, D.; Bret, J.L.; Ayela, F.; Coron, N.; Gonzalez-Mestres, L.


    This publication gather several courses which propose or address: Thermal conduction, Kapitza resistance, Metal-insulator transition, Thermal properties and specific heat at low temperature, Thermometry, Low temperature superconductors, Defects due to irradiations in solids, Semiconducting detectors, Techniques of protection of a measurement assembly at low temperatures against perturbations, Noise reduction by impedance matching converter at low temperature, Low noise electronics and measurement, Low radio-activities, SQUID and electrometer, Results and expectations related to bolometers, Infrared and sub-millimetre radiation in astrophysics, Neutrinos, dark matter and heavy ions

  7. The hyperreality of clinical ethics: a unitary theory and hermeneutics. (United States)

    Ten Have, H


    Medical ethics nowadays is dominated by a conception of ethics as the application of moral theories and principles. This conception is criticized for its depreciation of the internal morality of medical practice and its narrow view of external morality. This view reflects both a lack of interest in the empirical realities of medicine and a neglect of the socio-cultural value-contexts of medical ethical issues, including the creative development of a broader philosophical framework for a practicable medical ethics. Several alternative approaches and conceptions have been proposed. The unified clinical ethics theory, developed by Graber and Thomasma, is an interesting attempt to synthesize these alternative approaches. It correctly identifies as the crucial problem the present disconnectedness of medical ethics from theoretical philosophy as well as the practice of medicine. In this paper, however, it is argued that the unitary theory should take more serious attention to the hermeneutic character of medicine as well as ethics. This implies that the unitary theory must in fact transform itself into an interpretive clinical ethics theory. The theoretical characteristics and practical consequences of an interpretive theory of medical ethics are discussed in the present paper.


    International Nuclear Information System (INIS)

    Pike, J


    Liquid Waste Organization (LWO) identified aluminum dissolution as a method to mitigate the effect of having about 50% more solids in High Level Waste (HLW) sludge than previously planned. Previous aluminum dissolution performed in a HLW tank in 1982 was performed at approximately 85 C for 5 days, which became the baseline aluminum dissolution process. LWO initiated a project to modify a waste tank to meet these requirements. Subsequent to an alternative evaluation, LWO management identified an opportunity to perform aluminum dissolution on sludge destined for Sludge Batch 5, but within a limited window that would not allow time for any modifications for tank heating. A variation of the baseline process, dubbed Low Temperature Aluminum Dissolution (LTAD), was developed based on the constraint of available energy input in Tank 51 and the window of opportunity, but was not constrained to a minimum extent of dissolution, i.e. dissolve as much aluminum as possible within the time available. This process was intended to operate between 55 and 70 C, but for a significantly longer time than the baseline process. LTAD proceeded in parallel with the baseline project. The preliminary evaluation at the completion of LTAD focused on the material balance and extent of the aluminum dissolved. The range of values of extent of dissolution, 56% to 64%, resulted from the variation in liquid phase sample data available at the time. Additional solid phase data is available from a sample taken after LTAD to refine this range. This report provides additional detailed evaluation of the LTAD process based on analytical and field data and includes: a summary of the process chronology; a determination of an acceptable blending strategy for the aluminum-laden supernate stored in Tank 11; an update to the determination of aluminum dissolved using more complete sample results; a determination of the effect of LTAD on uranium, plutonium, and other metals; a determination of the rate of heat

  9. Low temperature electrical and photo-responsive properties of MoSe2

    DEFF Research Database (Denmark)

    Fan, Chao; Yue, Qu; Yang, Juehan


    MoSe2 was fabricated by a facile hydrothermal method, and a simple device based on it was prepared to investigate the low temperature electrical and photo-responsive (PR) properties. PR current of MoSe2 under 650 nm red illumination is 2.55 × 10−5 A and remains approximately at low temperatures, ...

  10. Analysis and research on promising solutions of low temperature district heating without risk of legionella

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Fog, Jette M.


    resources. The most crucial restriction for applying low temperature district heating is the worry about the breakout of legionella, which exists preferably in low temperature hot water systems. Several novel techniques such as electric tracing and flat station were investigated for such dilemma. The pros...

  11. Achieving low return temperature for domestic hot water preparation by ultra-low-temperature district heating

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Svendsen, Svend


    District heating (DH) is a cost-effective method of heat supply, especially to area with high heat density. Ultra-low-temperature district heating (ULTDH) is defined with supply temperature at 35-45 degrees C. It aims at making utmost use of the available low-temperature energy sources. In order ...

  12. Comparison Of Different Noble Metal Catalysts For The Low Temperature Catalytic Partial Oxidation Of Methane

    Energy Technology Data Exchange (ETDEWEB)

    Rabe, S.; Truong, T.-B.; Vogel, F.


    The generation of synthesis gas at low temperatures can contribute to a more economic production of clean transportation fuels (Fischer-Tropsch liquids) from natural gas. In this report, the performance of different noble metal catalysts in a low temperature catalytic partial oxidation process is presented. (author)

  13. Low-temperature atomic layer deposition delivers more active and stable Pt-based catalysts

    NARCIS (Netherlands)

    Bui, H.V.; Grillo, F.; Kulkarni, S.S.; Bevaart, Ronald; Nguyên, V.T.; van der Linden, B.; Moulijn, J.A.; Makkee, M.; Kreutzer, M.T.; van Ommen, J.R.


    We tailored the size distribution of Pt nanoparticles (NPs) on graphene nanoplatelets at a given metal loading by using low-temperature atomic layer deposition carried out in a fluidized bed reactor operated at atmospheric pressure. The Pt NPs deposited at low temperature (100 °C) after 10 cycles

  14. Effect of low temperature during the night in young sweet pepper plants

    NARCIS (Netherlands)

    Gorbe Sanchez, Elisa; Heuvelink, E.; Jalink, H.; Stanghellini, C.


    The optimization of heating in greenhouses should be an energy saving target in the cultivation of sweet pepper plants; from both an environmental and economical point of view. It is important to understand the effect of low temperatures on this crop. While the effect of low temperature has been

  15. Bioelectrochemical enhancement of methane production in low temperature anaerobic digestion at 10 °C

    NARCIS (Netherlands)

    Liu, Dandan; Zhang, Lei; Chen, Si; Buisman, Cees; Heijne, ter Annemiek


    Anaerobic digestion at low temperature is an attractive technology especially in moderate climates, however, low temperature results in low microbial activity and low rates of methane formation. This study investigated if bioelectrochemical systems (BESs) can enhance methane production from

  16. Generalized Grüneisen parameters and low temperature limit of ...

    Indian Academy of Sciences (India)

    The generalized Grüneisen parameters ( j ′ ) and ( j ″ ) for cadmium and zirconium were calculated from the second- and third-order elastic constants to determine the low temperature limit of the volume thermal expansion of these metals of hexagonal symmetry. The low temperature limit of cadmium and zirconium ...

  17. Compactifications of the Heterotic string with unitary bundles

    Energy Technology Data Exchange (ETDEWEB)

    Weigand, T.


    In this thesis we investigate a large new class of four-dimensional supersymmetric string vacua defined as compactifications of the E{sub 8} x E{sub 8} and the SO(32) heterotic string on smooth Calabi-Yau threefolds with unitary gauge bundles and heterotic five-branes. The first part of the thesis discusses the implementation of this idea into the E{sub 8} x E{sub 8} heterotic string. After specifying a large class of group theoretic embeddings featuring unitary bundles, we analyse the effective four-dimensional N=1 supergravity upon compactification. From the gauge invariant Kaehler potential for the moduli fields we derive a modification of the Fayet-Iliopoulos D-terms arising at one-loop in string perturbation theory. From this we conjecture a one-loop deformation of the Hermitian Yang-Mills equation and introduce the idea of {lambda}-stability as the perturbatively correct stability concept generalising the notion of Mumford stability valid at tree-level. We then proceed to a definition of SO(32) heterotic vacua with unitary gauge bundles in the presence of heterotic five-branes and find agreement of the resulting spectrum with the S-dual framework of Type I/Type IIB orientifolds. A similar analysis of the effective four-dimensional supergravity is performed. Further evidence for the proposed one-loop correction to the stability condition is found by identifying the heterotic corrections as the S-dual of the perturbative part of {pi}-stability as the correct stability concept in Type IIB theory. After reviewing the construction of holomorphic stable vector bundles on elliptically fibered Calabi-Yau manifolds via spectral covers, we provide semi-realistic examples for SO(32) heterotic vacua with Pati-Salam and MSSM-like gauge sectors. We finally discuss the construction of realistic vacua with flipped SU(5) GUT and MSSM gauge group within the E{sub 8} x E{sub 8} framework, based on the embedding of line bundles into both E{sub 8} factors. Some of the appealing

  18. The Schur algorithm for generalized Schur functions III : J-unitary matrix polynomials on the circle

    NARCIS (Netherlands)

    Alpay, Daniel; Azizov, Tomas; Dijksma, Aad; Langer, Heinz


    The main result is that for J = ((1)(0) (0)(-1)) every J-unitary 2 x 2-matrix polynomial on the unit circle is an essentially unique product of elementary J-unitary 2 x 2-matrix polynomials which are either of degree 1 or 2k. This is shown by means of the generalized Schur transformation introduced

  19. Qubit transport model for unitary black hole evaporation without firewalls* (United States)

    Osuga, Kento; Page, Don N.


    We give an explicit toy qubit transport model for transferring information from the gravitational field of a black hole to the Hawking radiation by a continuous unitary transformation of the outgoing radiation and the black hole gravitational field. The model has no firewalls or other drama at the event horizon, and it avoids a counterargument that has been raised for subsystem transfer models as resolutions of the firewall paradox. Furthermore, it fits the set of six physical constraints that Giddings has proposed for models of black hole evaporation. It does utilize nonlocal qubits for the gravitational field but assumes that the radiation interacts locally with these nonlocal qubits, so in some sense the nonlocality is confined to the gravitational sector. Although the qubit model is too crude to be quantitatively correct for the detailed spectrum of Hawking radiation, it fits qualitatively with what is expected.

  20. Momentum Distribution in the Unitary Bose Gas from First Principles. (United States)

    Comparin, Tommaso; Krauth, Werner


    We consider a realistic bosonic N-particle model with unitary interactions relevant for Efimov physics. Using quantum Monte Carlo methods, we find that the critical temperature for Bose-Einstein condensation is decreased with respect to the ideal Bose gas. We also determine the full momentum distribution of the gas, including its universal asymptotic behavior, and compare this crucial observable to recent experimental data. Similar to the experiments with different atomic species, differentiated solely by a three-body length scale, our model only depends on a single parameter. We establish a weak influence of this parameter on physical observables. In current experiments, the thermodynamic instability of our model from the atomic gas towards an Efimov liquid could be masked by the dynamical instability due to three-body losses.

  1. Territory in the Constitutional Standards of Unitary States

    Directory of Open Access Journals (Sweden)

    Marina V. Markhgeym


    Full Text Available The article is based on the analysis of the constitutions of seven European countries (Albania, Hungary, Greece, Spain, Malta, Poland, Sweden. The research allows to reveal general and specific approaches to consolidation of norms on territories in a state and give the characteristic of the corresponding constitutional norms. Given the authors ' comprehensive approach to the definition of the territory of the state declared constitutional norms were assessed from the perspective of the fundamental principles and constituent elements of the territory. Considering the specifics of the constitutional types of state territories authors suggest typical and variative models and determine the constitutions of unitary states, distinguished by their originality in the declared group of legal relations. The original constitutional language areas associated with the introduction at the state level, these types of areas that are not typical for other countries.

  2. An Informal Overview of the Unitary Group Approach

    Energy Technology Data Exchange (ETDEWEB)

    Sonnad, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Escher, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kruse, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Baker, R. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Physics and Astronomy


    The Unitary Groups Approach (UGA) is an elegant and conceptually unified approach to quantum structure calculations. It has been widely used in molecular structure calculations, and holds the promise of a single computational approach to structure calculations in a variety of different fields. We explore the possibility of extending the UGA to computations in atomic and nuclear structure as a simpler alternative to traditional Racah algebra-based approaches. We provide a simple introduction to the basic UGA and consider some of the issues in using the UGA with spin-dependent, multi-body Hamiltonians requiring multi-shell bases adapted to additional symmetries. While the UGA is perfectly capable of dealing with such problems, it is seen that the complexity rises dramatically, and the UGA is not at this time, a simpler alternative to Racah algebra-based approaches.

  3. The SNARC effect is not a unitary phenomenon. (United States)

    Basso Moro, Sara; Dell'Acqua, Roberto; Cutini, Simone


    Models of the spatial-numerical association of response codes (SNARC) effect-faster responses to small numbers using left effectors, and the converse for large numbers-diverge substantially in localizing the root cause of this effect along the numbers' processing chain. One class of models ascribes the cause of the SNARC effect to the inherently spatial nature of the semantic representation of numerical magnitude. A different class of models ascribes the effect's cause to the processing dynamics taking place during response selection. To disentangle these opposing views, we devised a paradigm combining magnitude comparison and stimulus-response switching in order to monitor modulations of the SNARC effect while concurrently tapping both semantic and response-related processing stages. We observed that the SNARC effect varied nonlinearly as a function of both manipulated factors, a result that can hardly be reconciled with a unitary cause of the SNARC effect.

  4. The Science of Unitary Human Beings in a Creative Perspective. (United States)

    Caratao-Mojica, Rhea


    In moving into a new kind of world, nurses are encouraged to look ahead and be innovative by transcending to new ways of using nursing knowledge while embracing a new worldview. "We need to recognize that we're going to have to use our imagination more and more" (Rogers, 1994). On that note, the author in this paper explicates Rogers' science of unitary human beings in a creative way relating it to painting. In addition, the author also explores works derived from Rogers' science such as Butcher's (1993) and Cowling's (1997), which are here discussed in light of an artwork. A painting is presented with the unpredictability, creativity, and the "dance of color and light" (Butcher, 1993) is appreciated through comprehending essence, pandimensionality, and wholeness. © The Author(s) 2015.

  5. Mesoscopic Fluctuations for the Thinned Circular Unitary Ensemble (United States)

    Berggren, Tomas; Duits, Maurice


    In this paper we study the asymptotic behavior of mesoscopic fluctuations for the thinned Circular Unitary Ensemble. The effect of thinning is that the eigenvalues start to decorrelate. The decorrelation is stronger on the larger scales than on the smaller scales. We investigate this behavior by studying mesoscopic linear statistics. There are two regimes depending on the scale parameter and the thinning parameter. In one regime we obtain a CLT of a classical type and in the other regime we retrieve the CLT for CUE. The two regimes are separated by a critical line. On the critical line the limiting fluctuations are no longer Gaussian, but described by infinitely divisible laws. We argue that this transition phenomenon is universal by showing that the same transition and their laws appear for fluctuations of the thinned sine process in a growing box. The proofs are based on a Riemann-Hilbert problem for integrable operators.

  6. Nonclassicality by Local Gaussian Unitary Operations for Gaussian States

    Directory of Open Access Journals (Sweden)

    Yangyang Wang


    Full Text Available A measure of nonclassicality N in terms of local Gaussian unitary operations for bipartite Gaussian states is introduced. N is a faithful quantum correlation measure for Gaussian states as product states have no such correlation and every non product Gaussian state contains it. For any bipartite Gaussian state ρ A B , we always have 0 ≤ N ( ρ A B < 1 , where the upper bound 1 is sharp. An explicit formula of N for ( 1 + 1 -mode Gaussian states and an estimate of N for ( n + m -mode Gaussian states are presented. A criterion of entanglement is established in terms of this correlation. The quantum correlation N is also compared with entanglement, Gaussian discord and Gaussian geometric discord.

  7. The genetic architecture of low-temperature adaptation in the wine yeast Saccharomyces cerevisiae. (United States)

    García-Ríos, Estéfani; Morard, Miguel; Parts, Leopold; Liti, Gianni; Guillamón, José M


    Low-temperature growth and fermentation of wine yeast can enhance wine aroma and make them highly desirable traits for the industry. Elucidating response to cold in Saccharomyces cerevisiae is, therefore, of paramount importance to select or genetically improve new wine strains. As most enological traits of industrial importance in yeasts, adaptation to low temperature is a polygenic trait regulated by many interacting loci. In order to unravel the genetic determinants of low-temperature fermentation, we mapped quantitative trait loci (QTLs) by bulk segregant analyses in the F13 offspring of two Saccharomyces cerevisiae industrial strains with divergent performance at low temperature. We detected four genomic regions involved in the adaptation at low temperature, three of them located in the subtelomeric regions (chromosomes XIII, XV and XVI) and one in the chromosome XIV. The QTL analysis revealed that subtelomeric regions play a key role in defining individual variation, which emphasizes the importance of these regions' adaptive nature. The reciprocal hemizygosity analysis (RHA), run to validate the genes involved in low-temperature fermentation, showed that genetic variation in mitochondrial proteins, maintenance of correct asymmetry and distribution of phospholipid in the plasma membrane are key determinants of low-temperature adaptation.

  8. Radiation detection at very low temperature. DRTBT 1992 -Londe-Les-Maures - Course collection

    International Nuclear Information System (INIS)

    Bellefon, A. de; Serra, Guy; Broniatowski, A.; Giraud-Heraud, Y.; Bruere Dawson, R.; Waysand, G.; Maneval, J.P.; Jacquier, B.; Leotin, J.; Chapellier, M.; Beaudin, G.; Encrenaz, P.; Gheudin, M.; Lamarre, J.M.; Ravex, A.; Godfrin, H.; Bret, J.L.; Gianese, Chr.; Torre, J.P.; Marcillac, P. de; Benoit, A.; Jegoudez, G.; Pari, P.


    The contributions addressed various themes: Cooled sensors, what are they for? (Search for rare events; Astrophysics, X rays and infrared, Spectrometry in nuclear physics); Cooled sensors (Bolometer physics, Bolometers for photometry, Bolometers for particle detection, Superconducting sensors, Other types of bolometers, Low temperature luminescence, Photo-conductors and photovoltaic BIB, Ionisation at very low temperature, Heterodyne detection); Problems related to the signal (Photometry and external measurement noise, Line, amplification and signal processing), Pulse measurement (Line and amplification, Signal processing), Cryogenics (Cryogenic machines, Very low temperature cryogenics, Noise and environment). Nota: contributions are printed in a different order than they are listed in the table of contents

  9. Low Temperature Transformation of Fe-Pd and Fe-Pt Invar Alloys


    Masaaki, Matsui; Kengo, Adachi; Hidefumi, Asano; Department of Iron and Steel Engineering, Faculty of Engineering Nagoya University; Department of Iron and Steel Engineering, Faculty of Engineering Nagoya University; Department of Iron and Steel Engineering, Faculty of Engineering Nagoya University


    Low temperature structures of Fe-Pd and Fe-Pt alloys in the Invar region have been determined by means of low temperature X-ray diffraction experiment. The phase diagrams are obtained. A new fct phase is found in the ordered and disordered Fe-Pt and the disordered Fe-Pd systems. An effect of the degree of order for Fe_3Pt to the structural transformations are examined. The lattice instability of Fe-based fcc Invar alloys are discussed from the low temperature structures with the lattice softe...

  10. Factorization of J-unitary matrix polynomials on the line and a Schur algorithm for generalized Nevanlinna functions

    NARCIS (Netherlands)

    Alpay, D.; Dijksma, A.; Langer, H.


    We prove that a 2 × 2 matrix polynomial which is J-unitary on the real line can be written as a product of normalized elementary J-unitary factors and a J-unitary constant. In the second part we give an algorithm for this factorization using an analog of the Schur transformation.

  11. Bi-directional modulation of AMPA receptor unitary conductance by synaptic activity

    Directory of Open Access Journals (Sweden)

    Matthews Paul


    Full Text Available Abstract Background Knowledge of how synapses alter their efficiency of communication is central to the understanding of learning and memory. The most extensively studied forms of synaptic plasticity are long-term potentiation (LTP and its counterpart long-term depression (LTD of AMPA receptor-mediated synaptic transmission. In the CA1 region of the hippocampus, it has been shown that LTP often involves a rapid increase in the unitary conductance of AMPA receptor channels. However, LTP can also occur in the absence of any alteration in AMPA receptor unitary conductance. In the present study we have used whole-cell dendritic recording, failures analysis and non-stationary fluctuation analysis to investigate the mechanism of depotentiation of LTP. Results We find that when LTP involves an increase in unitary conductance, subsequent depotentiation invariably involves the return of unitary conductance to pre-LTP values. In contrast, when LTP does not involve a change in unitary conductance then depotentiation also occurs in the absence of any change in unitary conductance, indicating a reduction in the number of activated receptors as the most likely mechanism. Conclusions These data show that unitary conductance can be bi-directionally modified by synaptic activity. Furthermore, there are at least two distinct mechanisms to restore synaptic strength from a potentiated state, which depend upon the mechanism of the previous potentiation.

  12. Carbon and nitrogen metabolism in arbuscular mycorrhizal maize plants under low-temperature stress

    DEFF Research Database (Denmark)

    Zhu, Xian-Can; Song, Feng-Bin; Liu, Fulai


    Effects of the arbuscular mycorrhizal (AM) fungus Glomus tortuosum on carbon (C) and nitrogen (N) metabolism of Zea mays L. grown under low-temperature stress was investigated. Maize plants inoculated or not inoculated with AM fungus were grown in a growth chamber at 258C for 4 weeks...... plants were higher than those of non-AM plants. AM plants had a higher net photosynthetic rate (Pn) than non-AM plants, although low temperature inhibited the Pn. Compared with non-AM plants, AM plants exhibited higher leaf soluble sugars, reducing sugars, root sucrose and fructose contents, and sucrose...... phosphate synthase and amylase activities at low temperature. Moreover, low-temperature stress increased theC :Nratio in the leaves of maize plants, and AM colonisation decreased the root C :N ratio. These results suggested a difference in the C and N metabolism of maize plants at ambient and low...

  13. Rugged Low Temperature Actuators for Tunable Fabry Perot Optical Filters, Phase I (United States)

    National Aeronautics and Space Administration — During our Phase I SBIR research, we propose to integrate a novel low-temperature large-strain actuator technology into Fabry-Perot optical filters. The resulting...

  14. Comparison of Low-temperature District Heating Concepts in a Long-Term Energy System Perspective

    DEFF Research Database (Denmark)

    Lund, Rasmus Søgaard; Østergaard, Dorte Skaarup; Yang, Xiaochen


    District heating systems are important components in an energy efficient heat supply. With increasing amounts of renewable energy, the foundation for district heating is changing and the approach to its planning will have to change. Reduced temperatures of district heating are proposed...... as a solution to adapt it to future renewable energy systems. This study compares three alternative concepts for district heating temperature level: Low temperature (55/25 oC), Ultra-low temperature with electric boosting (45/25 oC), and Ultra-low temperature with heat pump boosting (35/20 oC) taking...... into account the grid losses, production efficiencies and building requirements. The scenarios are modelled and analysed in the analysis tool EnergyPLAN and compared on primary energy supply and socioeconomic costs. The results show that the low temperature solution (55/25 oC) has the lowest costs, reducing...

  15. Influence of extreme low temperature conditions on the dynamic mechanical properties of carbon fiber reinforced polymers (United States)

    Zaoutsos, S. P.; Zilidou, M. C.


    In the current study dynamic mechanical analysis (DMA) is performed in CFRPs that have been exposed for certain periods of time to extreme low temperatures. Through experimental data arising from respective DMA tests the influence of low temperature exposure (-40 °C) on the dynamic mechanical properties is studied. DMA tests were conducted in CFRP specimens in three point bending mode at both frequency and thermal scans in order to determine the viscoelastic response of the material in low temperatures. All experimental tests were run both for aged and pristine materials for comparison purposes. The results occurred reveal that there is deterioration both on transition temperature (Tg) and storage modulus values while there is also a moderate increase in the damping ability of the tested material as expressed by the factor tanδ as the period of exposure to low temperature increases.

  16. Internal friction and magnetic after-effect anomalies in pure iron at low temperatures

    International Nuclear Information System (INIS)

    Dufresne, J.F.; Moser, P.; Ritchie, I.G.


    The magnetomechanical properties of iron at low temperature are affected by a large anomalous drop of the magnetic permeability which can be induced by a magnetic or elastic perturbation as low as H=20 Oe epsilon=10 -5

  17. Treatment of the early-stage glottic cancer using low-temperature radiofrequency coblation

    Directory of Open Access Journals (Sweden)

    Bing Liu


    Conclusions: Although the current probe design has limitations for the resection of certain tumors, low-temperature RF coblation appears to be a potentially effective method for the endoscopic resection of selected glottic cancers.

  18. The development of low-temperature calorimeter on the Peltier elements (United States)

    Baturevich, Tatyana; Tyagunin, Anatoly


    The article is devoted to the design of low-temperature calorimeter on the Peltier elements. This calorimeter can be used to study the temperature dependence of the specific heat capacity of different substances.

  19. The Low Temperature Induced Physiological Responses of Avena nuda L., a Cold-Tolerant Plant Species

    Directory of Open Access Journals (Sweden)

    Wenying Liu


    Full Text Available The paperaim of the was to study the effect of low temperature stress on Avena nuda L. seedlings. Cold stress leads to many changes of physiological indices, such as membrane permeability, free proline content, malondialdehyde (MDA content, and chlorophyll content. Cold stress also leads to changes of some protected enzymes such as peroxidase (POD, superoxide dismutase (SOD, and catalase (CAT. We have measured and compared these indices of seedling leaves under low temperature and normal temperature. The proline and MDA contents were increased compared with control; the chlorophyll content gradually decreased with the prolongation of low temperature stress. The activities of SOD, POD, and CAT were increased under low temperature. The study was designated to explore the physiological mechanism of cold tolerance in naked oats for the first time and also provided theoretical basis for cultivation and antibiotic breeding in Avena nuda L.

  20. A Plateau-Burning, Low Temperature-Operable Solid Propellant for Mars Sample Return, Phase I (United States)

    National Aeronautics and Space Administration — The Mars ascent vehicle (MAV) is required to endure a long space transit time, high-g loading during planetary entry, and high launch loads, all at low temperatures...

  1. Rugged Low Temperature Actuators for Tunable Fabry Perot Optical Filters, Phase II (United States)

    National Aeronautics and Space Administration — Why are rugged, low temperature actuator materials important? By themselves, they are useless; however, when fabricated into thin films and integrated into optical...

  2. Liquefied Gas Catholytes for UItra-Low Temperature Lithium Primary Batteries, Phase I (United States)

    National Aeronautics and Space Administration — NASA's Ocean Worlds exploration missions require batteries which operate as low as -100 C (defined here are "Ultra-Low Temperatures") and lower, a critically...


    Low temperature evaporation and reverse osmosis systems were each evaluated (on a pilot scale) on their respective ability to process rinse water collected from a nickel electroplating operation. Each system offered advantages under specific operating conditions. The low temperat...

  4. Micromachined Active Magnetic Regenerator for Low Temperature Magnetic Coolers, Phase I (United States)

    National Aeronautics and Space Administration — NASA's future science missions to investigate the structure and evolution of the universe require highly efficient, very low temperature coolers for low noise...

  5. Engineering low-temperature expression systems for heterologous production of cold-adapted enzymes. (United States)

    Bjerga, Gro Elin Kjæreng; Lale, Rahmi; Williamson, Adele Kim


    Production of psychrophilic enzymes in the commonly used mesophilic expression systems is hampered by low intrinsic stability of the recombinant enzymes at the optimal host growth temperatures. Unless strategies for low-temperature expression are advanced, research on psychrophilic enzymes may end up being biased toward those that can be stably produced in commonly used mesophilic host systems. Two main strategies are currently being explored for the development of low-temperature expression in bacterial hosts: (i) low-temperature adaption of existing mesophilic expression systems, and (ii) development of new psychrophilic hosts. These developments include genetic engineering of the expression cassettes to optimize the promoter/operator systems that regulate heterologous expression. In this addendum we present our efforts in the development of such low-temperature expression systems, and speculate about future advancements in the field and potential applications.

  6. Numerical evaluation of induction heating assisted compaction technology for low temperature asphalt pavement construction

    NARCIS (Netherlands)

    Zhou, C.; Liu, X.; Apostolidis, P.


    Low Temperature Asphalt (LTA) technologies are utilized in asphalt pavement industry to lower energy demands and greenhouse gas emission during mixing and construction processes. Although these technologies are currently available and hope to demonstrate similar performance with Hot Mix Asphalt

  7. Experimental research on sealing performance of sulfur hexafluoride electrical equipment under low-temperature environment (United States)

    Li, G. X.; Li, L.; Zhang, R.; Jiang, Z. Q.; Zhu, X. C.; Gao, Z. W.; Zhang, H. D.; Zhang, J.


    It is discovered that the sealing performance of the sulfur hexafluoride electrical equipment worsens under low temperature, but research in the aspect is reported rarely when corresponding measures are adopted for improving the sealing performance of electrical equipment. Therefore, sealing and leakage test of sulfur hexafluoride electrical equipment was implemented under low-temperature environment according to the analysis on gas sealing methods of sulfur hexafluoride electrical equipment. Causes of gas leakage of sulfur hexafluoride electrical equipment under low temperature environment were analyzed according to test results. Effective measures were proposed for improving the gas sealing performance of the equipment, thereby providing valuable reference for gas sealing design, installation, operation maintenance and failure analysis of sulfur hexafluoride electrical equipment under low - temperature environment.

  8. Low temperature fiber optic pyrometer for fast time resolved temperature measurements (United States)

    Willsch, M.; Bosselmann, T.; Gaenshirt, D.; Kaiser, J.; Villnow, M.; Banda, M.


    Low temperature Pyrometry at temperatures beyond 150°C is limited in the measurement speed due to slow pyroelectric detectors. To detect the circumferential temperature distribution of fast rotating machines a novel Fiber Optical Pyrometer Type is presented here.

  9. Linking the Unitary Paradigm to Policy through a Synthesis of Caring Science and Integrative Nursing. (United States)

    Koithan, Mary S; Kreitzer, Mary Jo; Watson, Jean


    The principles of integrative nursing and caring science align with the unitary paradigm in a way that can inform and shape nursing knowledge, patient care delivery across populations and settings, and new healthcare policy. The proposed policies may transform the healthcare system in a way that supports nursing praxis and honors the discipline's unitary paradigm. This call to action provides a distinct and hopeful vision of a healthcare system that is accessible, equitable, safe, patient-centered, and affordable. In these challenging times, it is the unitary paradigm and nursing wisdom that offer a clear path forward.

  10. Functional conservation analysis and expression modes of grape anthocyanin synthesis genes responsive to low temperature stress. (United States)

    Zhang, Cheng; Jia, Haifeng; Wu, Weimin; Wang, Xicheng; Fang, Jinggui; Wang, Chen


    In grape cultivation, low temperature generally increases the expression of genes involved in synthesis of anthocyanin. In this study, multi-type structural analysis of the proteins encoded by five anthocyanin biosynthesis genes VvF3H, VvPAL, VvCHS3, VvCHS2 and VvLDOX, in addition to nine of their homologous genes revealed that proteins in grapevine shared a high similarity with that in kiwi, red orange and some other species in which the biosynthesis of anthocyanin significantly influenced by low temperature as proved by previous studies. Low temperature regulatory elements were also found in the promoter region of the grapevine genes VvCHS2, VvPAL and VvF3H. These findings indicate that the functions of anthocyanin biosynthesis genes in grapevine are conservative and might be sensitive to low temperature. In order to identify the specific expression patterns of the five anthocyanin biosynthesis genes and the changes of polyphenols, anthocyanins and flavonoids under low temperature stress. The transcription analysis of the five genes and the content of polyphenols, anthocyanins and flavonoids in grape skins were examined, by using Vitis vinifera L. cv. 'Yongyou 1' and 'Juxing' berries as experimental material and treated at 4°C and 25°C for 24h, 48 h, 72 h and 96 h. The results showed that low temperature greatly enhanced the expression of the five anthocyanin biosynthesis genes. Low temperature greatly slowed down the decomposition of polyphenol, anthocyanin, and flavonoid in grape skins. Our study also found that cv. 'Juxing' responded more sensitively to low temperature than cv. 'Yongyou 1'. All the findings would provide a basis for further study on the mechanism of anthocyanin biosynthesis under environmental stress. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. influence of a low temperature ageing on the properties of al-6.5%si ...

    African Journals Online (AJOL)


    The effect of a low temperature ageing treatment on the hardness, tensile and corrosion characteristics of sand cast. Al-6.5%Si-0.35%Mg alloy was studied. The temper conditions are low temperature ageing at 90oC, 95oC, 100oCand. 105oC respectively followed by ageing to 180oC for 2 hrs. This was compared with the ...

  12. Advanced Low Temperature Geothermal Power Cycles (The ENTIV Organic Project) Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mugerwa, Michael [Technip USA, Inc., Claremont, CA (United States)


    Feasibility study of advanced low temperature thermal power cycles for the Entiv Organic Project. Study evaluates amonia-water mixed working fluid energy conversion processes developed and licensed under Kalex in comparison with Kalina cycles. Both cycles are developed using low temperature thermal resource from the Lower Klamath Lake Geothermal Area. An economic feasibility evaluation was conducted for a pilot plant which was deemed unfeasible by the Project Sponsor (Entiv).

  13. High-pressure cell for neutron scattering at very low temperatures

    International Nuclear Information System (INIS)

    Paureau, J.; Vettier, C.


    The high pressure cell for neutron scattering experiments at low temperatures described here consists of an autofreggated chamber and a shield. The bursting pressures for pressure cells of 7075-T6 and 7049A-T6 aluminium alloys have been measured at different temperatures. These studies demonstrate the feasibility and the safety of experiments at pressures up to 6 kbar at low temperatures. (author)

  14. Evidence from Fermi surface analysis for the low-temperature structure of lithium (United States)

    Elatresh, Sabri F.; Cai, Weizhao; Ashcroft, N. W.; Hoffmann, Roald; Deemyad, Shanti; Bonev, Stanimir A.


    The low-temperature crystal structure of elemental lithium, the prototypical simple metal, is a several-decades-old problem. At 1 atm pressure and 298 K, Li forms a body-centered cubic lattice, which is common to all alkali metals. However, a low-temperature phase transition was experimentally detected to a structure initially identified as having the 9R stacking. This structure, proposed by Overhauser in 1984, has been questioned repeatedly but has not been confirmed. Here we present a theoretical analysis of the Fermi surface of lithium in several relevant structures. We demonstrate that experimental measurements of the Fermi surface based on the de Haas-van Alphen effect can be used as a diagnostic method to investigate the low-temperature phase diagram of lithium. This approach may overcome the limitations of X-ray and neutron diffraction techniques and makes possible, in principle, the determination of the lithium low-temperature structure (and that of other metals) at both ambient and high pressure. The theoretical results are compared with existing low-temperature ambient pressure experimental data, which are shown to be inconsistent with a 9R phase for the low-temperature structure of lithium.

  15. Rooftop Unitary Air Conditioner with Integral Dedicated Outdoor Air System

    Energy Technology Data Exchange (ETDEWEB)

    Tiax Llc


    Energy use of rooftop and other unitary air-conditioners in commercial applications accounts for about 1 quad (10{sup 15} Btu) of primary energy use annually in the U.S. [Reference 7]. The realization that this cooling equipment accounts for the majority of commercial building cooled floorspace and the majority also of commercial building energy use has spurred development of improved-efficiency equipment as well as development of stricter standards addressing efficiency levels. Another key market driver affecting design of rooftop air-conditioning equipment has been concern regarding comfort and the control of humidity. Trends for increases in outdoor air ventilation rates in certain applications, and the increasing concern about indoor air quality problems associated with humidity levels and moisture in buildings points to a need for improved dehumidification capability in air-conditioning equipment of all types. In many cases addressing this issue exacerbates energy efficiency, and vice versa. The integrated dedicated outdoor air system configuration developed in this project addresses both energy and comfort/humidity issues.

  16. Unitary equivalence between ordinary intelligent states and generalized intelligent states

    International Nuclear Information System (INIS)

    Nha, Hyunchul


    Ordinary intelligent states (OISs) hold equality in the Heisenberg uncertainty relation involving two noncommuting observables (A,B), whereas generalized intelligent states (GISs) do so in the more generalized uncertainty relation, the Schroedinger-Robertson inequality. In general, OISs form a subset of GISs. However, if there exists a unitary evolution U that transforms the operators (A,B) to a new pair of operators in a rotation form, it is shown that an arbitrary GIS can be generated by applying the rotation operator U to a certain OIS. In this sense, the set of OISs is unitarily equivalent to the set of GISs. It is the case, for example, with the su(2) and the su(1,1) algebras which have been extensively studied, particularly in quantum optics. When these algebras are represented by two bosonic operators (nondegenerate case), or by a single bosonic operator (degenerate case), the rotation, or pseudorotation, operator U corresponds to phase shift, beam splitting, or parametric amplification, depending on two observables (A,B)

  17. Conditional mutual information of bipartite unitaries and scrambling

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Dawei; Hayden, Patrick; Walter, Michael [Stanford Institute for Theoretical Physics, Department of Physics, Stanford University,382 Via Pueblo, Stanford, CA 94305 (United States)


    One way to diagnose chaos in bipartite unitary channels is via the tripartite information of the corresponding Choi state, which for certain choices of the subsystems reduces to the negative conditional mutual information (CMI). We study this quantity from a quantum information-theoretic perspective to clarify its role in diagnosing scrambling. When the CMI is zero, we find that the channel has a special normal form consisting of local channels between individual inputs and outputs. However, we find that arbitrarily low CMI does not imply arbitrary proximity to a channel of this form, although it does imply a type of approximate recoverability of one of the inputs. When the CMI is maximal, we find that the residual channel from an individual input to an individual output is completely depolarizing when the other input is maximally mixed. However, we again find that this result is not robust. We also extend some of these results to the multipartite case and to the case of Haar-random pure input states. Finally, we look at the relationship between tripartite information and its Rényi-2 version which is directly related to out-of-time-order correlation functions. In particular, we demonstrate an arbitrarily large gap between the two quantities.

  18. Positive-definite functions and unitary representations of locally compact groups in a Hilbert space

    International Nuclear Information System (INIS)

    Gali, I.M.; Okb el-Bab, A.S.; Hassan, H.M.


    It is proved that the necessary and sufficient condition for the existence of an integral representation of a group of unitary operators in a Hilbert space is that it is positive-definite and continuous in some topology

  19. Low Temperature Geothermal Resource Assessment for Membrane Distillation Desalination in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Akar, Sertac; Turchi, Craig


    Substantial drought and declines in potable groundwater in the United States over the last decade has increased the demand for fresh water. Desalination of saline water such as brackish surface or groundwater, seawater, brines co-produced from oil and gas operations, industrial wastewater, blow-down water from power plant cooling towers, and agriculture drainage water can reduce the volume of water that requires disposal while providing a source of high-quality fresh water for industrial or commercial use. Membrane distillation (MD) is a developing technology that uses low-temperature thermal energy for desalination. Geothermal heat can be an ideal thermal-energy source for MD desalination technology, with a target range of $1/m3 to $2/m3 for desalinated water depending on the cost of heat. Three different cases were analyzed to estimate levelized cost of heat (LCOH) for integration of MD desalination technology with low-grade geothermal heat: (1) residual heat from injection brine at a geothermal power plant, (2) heat from existing underutilized low-temperature wells, and (3) drilling new wells for low-temperature resources. The Central and Western United States have important low-temperature (<90 degrees C) geothermal resource potential with wide geographic distribution, but these resources are highly underutilized because they are inefficient for power production. According to the USGS, there are 1,075 identified low temperature hydrothermal systems, 55 low temperature sedimentary systems and 248 identified medium to high temperature geothermal systems in the United States. The estimated total beneficial heat potential from identified low temperature hydrothermal geothermal systems and residual beneficial heat from medium to high temperature systems is estimated as 36,300 MWth, which could theoretically produce 1.4 to 7 million m3/day of potable water, depending on desalination efficiency.

  20. Low Temperature Geothermal Resource Assessment for Membrane Distillation Desalination in the United States: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Akar, Sertac; Turchi, Craig


    Substantial drought and declines in potable groundwater in the United States over the last decade has increased the demand for fresh water. Desalination of saline water such as brackish surface or groundwater, seawater, brines co-produced from oil and gas operations, industrial wastewater, blow-down water from power plant cooling towers, and agriculture drainage water can reduce the volume of water that requires disposal while providing a source of high-quality fresh water for industrial or commercial use. Membrane distillation (MD) is a developing technology that uses low-temperature thermal energy for desalination. Geothermal heat can be an ideal thermal-energy source for MD desalination technology, with a target range of $1/m3 to $2/m3 for desalinated water depending on the cost of heat. Three different cases were analyzed to estimate levelized cost of heat (LCOH) for integration of MD desalination technology with low-grade geothermal heat: (1) residual heat from injection brine at a geothermal power plant, (2) heat from existing underutilized low-temperature wells, and (3) drilling new wells for low-temperature resources. The Central and Western United States have important low-temperature (<90 degrees C) geothermal resource potential with wide geographic distribution, but these resources are highly underutilized because they are inefficient for power production. According to the USGS, there are 1,075 identified low temperature hydrothermal systems, 55 low temperature sedimentary systems and 248 identified medium to high temperature geothermal systems in the United States. The estimated total beneficial heat potential from identified low temperature hydrothermal geothermal systems and residual beneficial heat from medium to high temperature systems is estimated as 36,300 MWth, which could theoretically produce 1.4 to 7 million m3/day of potable water, depending on desalination efficiency.

  1. Development and industrial application of catalyzer for low-temperature hydrogenation hydrolysis of Claus tail gas

    Directory of Open Access Journals (Sweden)

    Honggang Chang


    Full Text Available With the implementation of more strict national environmental protection laws, energy conservation, emission reduction and clean production will present higher requirements for sulfur recovery tail gas processing techniques and catalyzers. As for Claus tail gas, conventional hydrogenation catalyzers are gradually being replaced by low-temperature hydrogenation catalyzers. This paper concentrates on the development of technologies for low-temperature hydrogenation hydrolysis catalyzers, preparation of such catalyzers and their industrial application. In view of the specific features of SO2 hydrogenation and organic sulfur hydrolysis during low-temperature hydrogenation, a new technical process involving joint application of hydrogenation catalyzers and hydrolysis catalyzers was proposed. In addition, low-temperature hydrogenation catalyzers and low-temperature hydrolysis catalyzers suitable for low-temperature conditions were developed. Joint application of these two kinds of catalyzers may reduce the inlet temperatures in the conventional hydrogenation reactors from 280 °C to 220 °C, at the same time, hydrogenation conversion rates of SO2 can be enhanced to over 99%. To further accelerate the hydrolysis rate of organic sulfur, the catalyzers for hydrolysis of low-temperature organic sulfur were developed. In lab tests, the volume ratio of the total sulfur content in tail gas can be as low as 131 × 10−6 when these two kinds of catalyzers were used in a proportion of 5:5 in volumes. Industrial application of these catalyzers was implemented in 17 sulfur recovery tail gas processing facilities of 15 companies. As a result, Sinopec Jinling Petrochemical Company had outstanding application performances with a tail gas discharging rate lower than 77.9 mg/m3 and a total sulfur recovery of 99.97%.

  2. A remark on the unitary group of a tensor product of n finite ...

    Indian Academy of Sciences (India)

    By using the method of quantum circuits in the theory of quantum computing as outlined in Nielsen and Chuang [2] and using a key lemma of Jaikumar [1] we show that every unitary operator on the tensor product H = H 1 ⊗ H 2 ⊗ … ⊗ H n can be expressed as a composition of a finite number of unitary operators living on ...

  3. Linear optical implementation of perfect discrimination between single-bit unitary operations

    International Nuclear Information System (INIS)

    Zhang Pei; Peng Liang; Wang Zhiwei; Ren Xifeng; Liu Biheng; Huang Yunfeng; Guo Guangcan


    Discrimination of unitary operations is a fundamental task of quantum information. Assisted by linear optical elements, we experimentally demonstrate perfect discrimination between single-bit unitary operations using the sequential scheme which is proved by Duan et al (Phys. Rev. Lett. 2007 98 100503). We also make a comparison with another perfect discrimination scheme called the parallel scheme. The complexity and resource consumed are analysed

  4. Development of a Novel Home Cogeneration System using a Polymer Electrolyte Fuel Cell which Enabled Air Conditioning by Its Low-TemperatureWaste Heat (United States)

    Nishimura, Nobuya; Honda, Kuniaki; Kawakami, Ryuichiro; Nishikawa, Toshimichi; Iyota, Hiroyuki; Nomura, Tomohiro

    Micro-scale distributed power generation system, which means a micro-cogeneration system in almost cases, has been paid a great attention from a standpoint of saving fossil fuels' consumption and preventing global warming. Especially, polymer electrolyte fuel cell (PEFC) is considered the most promising power generation system for small scale commercial use and residential use. In the PEFC cogeneration system, small amount of waste heat at low temperature from a cell stack is almost used to produce hot water. Therefore, in the paper, we proposed a new heat utilization method of the waste heat for air conditioning. In the proposed home cogeneration system, absorption refrigerator is introduced in order to produce chilled water. Thermal performances of the proposed system have been analyzed by a computer simulation which was developed for the prediction both of power generation characteristics of PEFC and absorption refrigerator's behavior.

  5. Analytical and unitary approach in mesons electromagnetic form factor applications

    International Nuclear Information System (INIS)

    Liptaj, A.


    In the dissertation thesis we address several topics related to the domain of particle physics. All of them represent interesting open problems that can be connected to the elastic or transition electromagnetic form factors of mesons, the form factors being the main objects of our interest. Our ambition is to contribute to the solution of these problems and use for that purpose known analytic properties of the form factors and the unitarity condition. These two tools are very powerful in the low energy domain (such as bound states of partons), where the perturbative QCD looses its validity. This is the motivation for construction of the unitary and analytic (U and A) models of studied form factors, that enable us to get the majority of our results. We use the U and A model to evaluate the contribution of the processes e + e - → Pγ, P = π 0 , η, η to the muon magnetic anomaly a μ in the lowest order of the hadronic vacuum polarization. For the contribution a μ had,LO (π + π - ) we demonstrate, that the use of the model leads to a dramatic error reduction with respect to the results of other authors. We also get a shift in the central value in the 'correct' direction, that brings the theoretical value closer to the experimental one. This results encourages us to use the model also for the evaluation of a μ had,LO (P γ ). These contributions are smaller, however the precision of the experiment makes their evaluation necessary. We further use the U and A model of the transition form factors of π 0 , η and η ' mesons to predict the partial decay widths of these particles Γ π 0 →γγ and Γ η→γγ and Γ η ' →γγ . In this way we make an independent cross check of the PDG table values. We find an agreement in the case of Γ η→γγ and Γ η ' →γγ , even a smaller uncertainty for Γ η ' →γγ . In the case of Γ π 0 →γγ we find a disagreement that points to an interesting problem. We wonder whether it

  6. Electrical transport in La1−xCaxMnO3 thin films at low temperatures

    Indian Academy of Sciences (India)

    Electrical transport in La1−xCaxMnO3 thin films at low temperatures. S ANGAPPANE, K SETHUPATHI and G RANGARAJAN. Physics Department, Low Temperature Laboratory, Indian Institute of Technology,. Chennai 600 036, India. Abstract. We report here the low-temperature resistivity of the chemical solution deposited.

  7. Effect of different arbuscular mycorrhizal fungi on growth and physiology of maize at ambient and low temperature regimes

    DEFF Research Database (Denmark)

    Chen, Xiaoying; Song, Fengbin; Liu, Fulai


    and soluble sugar contents under low temperature condition. The activities of catalase (CAT) and peroxidase of AM inoculated maize were higher than those of non-AM ones. Low temperature noticeably decreased the activities of CAT. The results suggest that low temperature adversely affects maize physiology...

  8. Unitary three-body calculation of nucleon-nucleon scattering

    International Nuclear Information System (INIS)

    Tanabe, H.; Ohta, K.


    We calculate nucleon-nucleon elastic scattering phase parameters based on a unitary, relativistic, pion-exchange model. The results are highly dependent on the off-shell amplitudes of πN scattering. The isobar-dominated model for the P 33 interaction leads to too small pion production rates owing to its strong suppression of off-shell pions. We propose to expand the idea of the Δ-isobar model in such a manner as to incorporate a background (non-pole) interaction. The two-potential model, which was first applied to the P 11 partial wave by Mizutani and Koltun, is applied also to the P 33 wave. Our phenomenological model for πN interaction in the P 33 partial wave differs from the conventional model only in its off-shell extrapolation, and has two different variants for the πN → Δ vertex. The three-body approach of Kloet and Silbar is extended such that the background interactions can be included straightfowardly. We make detailed comparisons of the new model with the conventional one and find that our model adequately reproduces the 1 D 2 phase parameters as well as those of peripheral partial waves. We also find that the longitudinal total cross section difference Δσ L (pp → NNπ) comes closer to the data compared to Kloet and Silbar. We discuss about the backward pion propagation in the three-body calculation, and the Pauli-principle violating states for the background P 11 interaction. (author)

  9. Tactical weapons algorithm development for unitary and fused systems (United States)

    Talele, Sunjay E.; Watson, John S.; Williams, Bradford D.; Amphay, Sengvieng A.


    A much needed capability in today's tactical Air Force is weapons systems capable of precision guidance in all weather conditions against targets in high clutter backgrounds. To achieve this capability, the Armament Directorate of Wright Laboratory, WL/MN, has been exploring various seeker technologies, including multi-sensor fusion, that may yield cost effective systems capable of operating under these conditions. A critical component of these seeker systems is their autonomous acquisition and tracking algorithms. It is these algorithms which will enable the autonomous operation of the weapons systems in the battlefield. In the past, a majority of the tactical weapon algorithms were developed in a manner which resulted in codes that were not releasable to the community, either because they were considered company proprietary or competition sensitive. As a result, the knowledge gained from these efforts was not transitioning through the technical community, thereby inhibiting the evolution of their development. In order to overcome this limitation, WL/MN has embarked upon a program to develop non-proprietary multi-sensor acquisition and tracking algorithms. To facilitate this development, a testbed has been constructed consisting of the Irma signature prediction model, data analysis workstations, and the modular algorithm concept evaluation tool (MACET) algorithm. All three of these components have been enhanced to accommodate both multi-spectral sensor fusion systems and the there dimensional signal processing techniques characteristic of ladar. MACET is a graphical interface driven system for rapid prototyping and evaluation of both unitary and fused sensor algorithms. This paper describes the MACET system and specifically elaborates on the three-dimensional capabilities recently incorporated into it.

  10. PREFACE: Low temperature Plasma in the Processes of Functional Coating Preparation (United States)

    Gali Yunusovich, Dautov; Kashapov Faikovich, Nail; Larionov, Viktor; Gerfanovich Zaripov, Renat; Galyautdinov Tagirovich, Raphael; Ilnaz, Fayrushin; Ramil Nailevich, Kashapov


    In November 2013 the V Republican Scientific Technical Conference 'Low-temperature plasma during the deposition of functional coatings' was held in Kazan. The Conference took place from 4-7 November at the Academy of Sciences of the Republic of Tatarstan and Kazan Federal University chaired by a member of the Academy of Sciences of the Republic of Tatarstan Nail Kashapov, Professor, Doctor of Technical Science, and a member of the Scientific and Technical Council of the Ministry of Economy of the Republic of Tatarstan. At the conference, the participants were offered a wide range of issues affecting the theoretical and computational aspects of the research problems in the physics and technology of low-temperature plasma. There was also a whole series of works devoted to the study of thin films, obtained by low-temperature plasma. For the second year at this conference, work dedicated to the related field of pulsation combustion and low- temperature plasma was considered. In addition much interest is devoted to reports on the exploration of gas discharges with liquid electrolytic electron trodes and the study of dusty plasmas. The VI All-Russian Conference 'Low-temperature plasma during the deposition of functional coatings', an extended version with international participation, is scheduled to take place in November 2014. Nail Kashapov Editor

  11. Evaluation of Asphalt Mixture Low-Temperature Performance in Bending Beam Creep Test (United States)

    Rys, Dawid; Jaskula, Piotr; Szydlowski, Cezary


    Low-temperature cracking is one of the most common road pavement distress types in Poland. While bitumen performance can be evaluated in detail using bending beam rheometer (BBR) or dynamic shear rheometer (DSR) tests, none of the normalized test methods gives a comprehensive representation of low-temperature performance of the asphalt mixtures. This article presents the Bending Beam Creep test performed at temperatures from −20 °C to +10 °C in order to evaluate the low-temperature performance of asphalt mixtures. Both validation of the method and its utilization for the assessment of eight types of wearing courses commonly used in Poland were described. The performed test indicated that the source of bitumen and its production process (and not necessarily only bitumen penetration) had a significant impact on the low-temperature performance of the asphalt mixtures, comparable to the impact of binder modification (neat, polymer-modified, highly modified) and the aggregate skeleton used in the mixture (Stone Mastic Asphalt (SMA) vs. Asphalt Concrete (AC)). Obtained Bending Beam Creep test results were compared with the BBR bitumen test. Regression analysis confirmed that performing solely bitumen tests is insufficient for comprehensive low-temperature performance analysis. PMID:29320443

  12. Lipid composition of wine strains of Saccharomyces kudriavzevii and Saccharomyces cerevisiae grown at low temperature. (United States)

    Tronchoni, Jordi; Rozès, Nicolas; Querol, Amparo; Guillamón, José Manuel


    Some species of the Saccharomyces genus have shown better adaptation at low temperature than the wine yeast Saccharomyces cerevisiae. That is the case of the cryophilic yeast Saccharomyces kudriavzevii. Several studies have revealed the importance of the lipid composition in the yeast adaptive response at different environmental temperatures. Thus we analysed the lipid composition of three S. kudriavzevii strains during growth at optimum (28°C) and low temperature (12°C), and compared them with different commercial strains; one S. cerevisiae strain and two hybrids between S. cerevisiae and S. kudriavzevii. Our results show a general increase in the medium-chain fatty acid, triacylglyceride, sterol esters and squalene and a decrease in the chain length of the fatty acids, in phosphatidic acid and in the ratio phosphatidylcholine/phosphatidylethanolamine at low temperatures. The S. kudriavzevii strains had higher percentages of medium-chain fatty acids and squalene and shorter chain lengths regardless of the growth temperature. This differential lipid composition may partially explain the better adaptation of S. kudriavzevii at low temperatures. We have also confirmed the better fermentation performance of the strains of this species at low temperature, being an appealing alternative to S. cerevisiae for cold fermentations. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Analysis of low temperature-induced genes (LTIG) in wine yeast during alcoholic fermentation. (United States)

    Chiva, Rosana; López-Malo, Maria; Salvadó, Zoel; Mas, Albert; Guillamón, Jósé Manuel


    Fermentations carried out at low temperatures, that is, 10-15 °C, not only enhance the production and retention of flavor volatiles, but also increase the chances of slowing or arresting the process. In this study, we determined the transcriptional activity of 10 genes that were previously reported as induced by low temperatures and involved in cold adaptation, during fermentation with the commercial wine yeast strain QA23. Mutant and overexpressing strains of these genes were constructed in a haploid derivative of this strain to determine the importance of these genes in growth and fermentation at low temperature. In general, the deletion and overexpression of these genes did affect fermentation performance at low temperature. Most of the mutants were unable to complete fermentation, while overexpression of CSF1, HSP104, and TIR2 decreased the lag phase, increased the fermentation rate, and reached higher populations than that of the control strain. Another set of overexpressing strains were constructed by integrating copies of these genes in the delta regions of the commercial wine strain QA23. These new stable overexpressing strains again showed improved fermentation performance at low temperature, especially during the lag and exponential phases. Our results demonstrate the convenience of carrying out functional analysis in commercial strains and in an experimental set-up close to industrial conditions. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  14. Low temperature treatment affects concentration and distribution of chrysanthemum stunt viroid in Argyranthemum

    Directory of Open Access Journals (Sweden)

    Zhibo eZhang


    Full Text Available Chrysanthemum stunt viroid (CSVd can infect Argyranthemum and cause serious economic loss. Low temperature treatment combined with meristem culture has been applied to eradicate viroids from their hosts, but without success in eliminating CSVd from diseased Argyranthemum. The objectives of this work were to investigate 1 the effect of low temperature treatment combined with meristem culture on elimination of CSVd, 2 the effect of low temperature treatment on CSVd distribution pattern in shoot apical meristem (SAM, and 3 CSVd distribution in flowers and stems of two infected Argyranthemum cultivars. After treatment with low temperature combined with meristem tip culture, two CSVd-free plants were found in ‘Border Dark Red’, but none in ‘Yellow Empire’. With the help of in situ hybridization, we found that CSVd distribution patterns in the SAM showed no changes in diseased ‘Yellow Empire’ following 5oC treatment, compared with non-treated plants. However, the CSVd-free area in SAM was enlarged in diseased ‘Border Dark Red’ following prolonged 5oC treatment. Localization of CSVd in the flowers and stems of infected ‘Border Dark Red’ and ‘Yellow Empire’ indicated that seeds could not transmit CSVd in these two cultivars, and CSVd existed in phloem. Results obtained in the study contributed to better understanding of the distribution of CSVd in systemically infected plants and the combination of low temperature treatment and meristem tip culture for production of viroid-free plants.

  15. Physiological response to low temperature in the freshwater apple snail, Pomacea canaliculata (Gastropoda: Ampullariidae). (United States)

    Matsukura, Keiichiro; Tsumuki, Hisaaki; Izumi, Yohei; Wada, Takashi


    Cold hardiness of the freshwater apple snail, Pomacea canaliculata, varies seasonally. We investigated lethal factors and physiological changes arising from exposure of P. canaliculata to low temperatures. Snails did not survive freezing. The supercooling point of cold-acclimated (cold tolerant) snails (-6.6+/-0.8 degrees C) did not differ significantly from that of non-acclimated ones (-7.1+/-1.5 degrees C) under laboratory conditions. Furthermore, snails died even under more moderately low temperatures approaching 0 degrees C. These results indicate that indirect chilling injury is a factor in the death of P. canaliculata at low temperatures. Regardless of whether the snails were acclimated to low temperatures, all of the dead, and even some of the snails still alive at 0 degrees C, had injured mantles, indicating that the mantle may be the organ most susceptible to the effects of low temperatures. The concentration of glucose in the posterior chamber of the kidney and concentration of glycerol in the digestive gland were significantly higher in cold-acclimated snails than in non-acclimated ones, suggesting carbohydrate metabolic pathways are altered in snails during cold acclimation.

  16. Low Temperature Performance Characteristics of Reclaimed Asphalt Pavement (RAP Mortars with Virgin and Aged Soft Binders

    Directory of Open Access Journals (Sweden)

    Feipeng Xiao


    Full Text Available Reclaimed asphalt pavement (RAP has many advantages and is utilized to improve the high temperature properties of asphalt mixtures. Low temperature cracking is a predominant distress in asphalt pavements containing RAP materials. Thus, the evaluation of fracture resistance for asphalt mixtures containing RAP is of interest. The objective of this research is to explore the low temperature performance characteristics of RAP mortars containing sieved RAP and soft binders at three aged states. The stiffness values and m-values from bending beam rheometer (BBR tests at three test temperatures of −18 °C, −12 °C and −6 °C were obtained to conduct the minimum low temperature grades. RAP mortar with a higher aged binder content had a higher minimum low temperature regardless of RAP source. In addition, RAP mortars with virgin soft binder had the best low temperature resistance followed by the RAP mortars with rolling thin film oven (RTFO and pressure-aged vessel (PAV binders.

  17. Low Temperature Plasma: A Novel Focal Therapy for Localized Prostate Cancer?

    Directory of Open Access Journals (Sweden)

    Adam M. Hirst


    Full Text Available Despite considerable advances in recent years for the focal treatment of localized prostate cancer, high recurrence rates and detrimental side effects are still a cause for concern. In this review, we compare current focal therapies to a potentially novel approach for the treatment of early onset prostate cancer: low temperature plasma. The rapidly evolving plasma technology has the potential to deliver a wide range of promising medical applications via the delivery of plasma-induced reactive oxygen and nitrogen species. Studies assessing the effect of low temperature plasma on cell lines and xenografts have demonstrated DNA damage leading to apoptosis and reduction in cell viability. However, there have been no studies on prostate cancer, which is an obvious candidate for this novel therapy. We present here the potential of low temperature plasma as a focal therapy for prostate cancer.

  18. On the nature of low temperature internal friction peaks in metallic glasses

    International Nuclear Information System (INIS)

    Khonik, V.A.; Spivak, L.V.


    Low temperature (30 60 Nb 40 subjected to preliminary inhomogeneous deformation by cold rolling, homogeneous tensile deformation or electrolytic charging with hydrogen is investigated. Cold rolling or hydrogenation result in appearance of similar internal friction peaks and hysteresis damping. Homogeneous deformation has no influence on low temperature internal friction. The phenomenon of microplastic deformation during hydrogenation of weakly stressed samples is revealed. It is argued that microplastic deformation of metallic glasses during hydrogenation without external stress takes place too. Plastic flow both on cold rolling and hydrogenation occurs via formation and motion of dislocation-like defects which are the reason of the observed anelastic anomalies. It is concluded that low temperature internal friction peaks described in the literature for as-cast, cold deformed and hydrogenated samples have common dislocation-like origin

  19. Comparative technical-economic analysis of the low temperature heating systems

    International Nuclear Information System (INIS)

    Sharevski, Vasko; Sharevski, Milan


    A method for comparative technical-economic analysis between low temperature heating systems and heating systems with fossil fuel boiler plant, heat pump heating system and electrical heating systems is presented. The single and combined heating systems are analyzed. The technical-economic priority application of the heating system is determined according to the prices of the low temperature heat energy, fossil fuel heat energy, electrical energy, as well as to the coefficient of the annual use of the installed heating capacity, investment expenses, structure of the combined heating system and coefficient of performances of the heat pump. The combined heating system, composed with a low temperature heating subsystem, which is used to cover the base heat demands, and a oil boiler plant heating subsystem, for the top heat demands, have technical-economic justification and wide range of priority application, in comparison with single heating systems. (author)

  20. On the nature of low temperature internal friction peaks in metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Khonik, V.A. [State Pedagogical Univ., Voronezh (Russian Federation); Spivak, L.V. [State Univ., Perm (Russian Federation)


    Low temperature (30 < T < 300 K) internal friction in a metallic glass Ni{sub 60}Nb{sub 40} subjected to preliminary inhomogeneous deformation by cold rolling, homogeneous tensile deformation or electrolytic charging with hydrogen is investigated. Cold rolling or hydrogenation result in appearance of similar internal friction peaks and hysteresis damping. Homogeneous deformation has no influence on low temperature internal friction. The phenomenon of microplastic deformation during hydrogenation of weakly stressed samples is revealed. It is argued that microplastic deformation of metallic glasses during hydrogenation without external stress takes place too. Plastic flow both on cold rolling and hydrogenation occurs via formation and motion of dislocation-like defects which are the reason of the observed anelastic anomalies. It is concluded that low temperature internal friction peaks described in the literature for as-cast, cold deformed and hydrogenated samples have common dislocation-like origin.

  1. Continuous Emission Spectrum Measurement for Electron Temperature Determination in Low-Temperature Collisional Plasmas

    International Nuclear Information System (INIS)

    Liu Qiuyan; Li Hong; Chen Zhipeng; Xie Jinlin; Liu Wandong


    Continuous emission spectrum measurement is applied for the inconvenient diagnostics of low-temperature collisional plasmas. According to the physical mechanism of continuous emission, a simplified model is presented to analyze the spectrum in low temperature plasma. The validity of this model is discussed in a wide range of discharge parameters, including electron temperature and ionization degree. Through the simplified model, the continuous emission spectrum in a collisional argon internal inductively coupled plasma is experimentally measured to determine the electron temperature distribution for different gas pressures and radio-frequency powers. The inverse Abel transform is also applied for a better spatially resoluted results. Meanwhile, the result of the continuous emission spectrum measurement is compared to that of the electrostatic double probes, which indicates the effectiveness of this method. (low temperature plasma)

  2. Disproportionation reaction of LaH2 at high pressure and low temperature (United States)

    Machida, A.; Watanuki, T.; Kawana, D.; Aoki, K.


    Structural change of LaH2 has been investigated at high pressure and low temperature by synchrotron radiation X-ray diffraction. LaH2 has an fcc metal lattice with interstitial hydrogen atoms located at tetrahedral sites. The fcc-LaH2 decomposes into two phases, which have different hydrogen compositions such as hydrogen-poor LaH and hydrogen -rich LaH2+δ phases, at 11 GPa at room temperature. In spite of largely suppressed diffusivity of the interstitial hydrogen atoms at low temperature, we have found the disproportionation reaction around 14 GPa at 200 K. Difference in the molar volume between each phases suggests monohydride LaH is formed as the disproportionation product even at low temperature. The volume fraction of the hydrogen-poor phase relative to the hydrogen-rich one at 200 K rapidly rises against pressure and reaches to ~0.45 at ~17 GPa.

  3. Integration of space heating and hot water supply in low temperature district heating

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael


    of the consumers involves both domestic hot water and space heating. Space heating may be provided at low temperature in low energy buildings. Domestic hot water, however, needs sufficient temperatures to avoid growth of legionella. If the network temperature is below the demand temperature, supplementary heating......District heating may supply many consumers efficiently, but the heat loss from the pipes to the ground is a challenge. The heat loss may be lowered by decreasing the network temperatures for which reason low temperature networks are proposed for future district heating. The heating demand...... is required by the consumer. We study conventional district heating at different temperatures and compare the energy and exergetic efficiency and annual heating cost to solutions that utilize electricity for supplementary heating of domestic hot water in low temperature district heating. This includes direct...

  4. Radiation detection at very low temperature. DRTBT 2002, Oleron - Course collection

    International Nuclear Information System (INIS)

    Pekola, J.; Charles, I.; Jin, Yong; Camus, Ph.; Juillard, A.; Chardin, G.; Leblanc, Elvire; Delabrouille, Jacques; Pigot, C.


    The contributions of this session addressed several themes: Tools (pumped helium-3 cryostats; dilution based cryostats; principle and application scope of demagnetisation devices; cooling by tunnel evaporation of electrons; very low temperatures without external cryogenic fluid), Very low temperature thermometry - resistive thermometry and its difficulties (temperature control, low temperature electronics), Bolometers (focussing, filtering and absorption; principle of a bolometer with resistive sensor, bolometer matrices, multiplexing; Anderson insulator; superconductors); Signal formation mechanism (high energy phonons, ballistic phonons and final thermalization), Signal acquisition and processing (reduction of noise due to the environment, from the cold pre-amplifier to the hard disk, signal processing and data analysis), and scientific culture (metrology, the microwave cosmological background, other astrophysical applications of cryogenic sensors). Contributions are printed in a different order than they listed in the table of contents

  5. Modeling thermal spike driven reactions at low temperature and application to zirconium carbide radiation damage (United States)

    Ulmer, Christopher J.; Motta, Arthur T.


    The development of TEM-visible damage in materials under irradiation at cryogenic temperatures cannot be explained using classical rate theory modeling with thermally activated reactions since at low temperatures thermal reaction rates are too low. Although point defect mobility approaches zero at low temperature, the thermal spikes induced by displacement cascades enable some atom mobility as it cools. In this work a model is developed to calculate "athermal" reaction rates from the atomic mobility within the irradiation-induced thermal spikes, including both displacement cascades and electronic stopping. The athermal reaction rates are added to a simple rate theory cluster dynamics model to allow for the simulation of microstructure evolution during irradiation at cryogenic temperatures. The rate theory model is applied to in-situ irradiation of ZrC and compares well at cryogenic temperatures. The results show that the addition of the thermal spike model makes it possible to rationalize microstructure evolution in the low temperature regime.

  6. Effect of low temperature on highly unsaturated fatty acid biosynthesis in activated sludge. (United States)

    He, Su; Ding, Li-Li; Xu, Ke; Geng, Jin-Ju; Ren, Hong-Qiang


    Low temperature is a limiting factor for the microbial activity of activated sludge for sewage treatment plant in winter. Highly unsaturated fatty acid (UFA) biosynthesis, phospholipid fatty acid (PLFA) constituents and microbial structure in activated sludge at low temperature were investigated. Over 12 gigabases of metagenomic sequence data were generated with the Illumina HiSeq 2000 platform. The result showed 43.11% of phospholipid fatty acid (PLFA) in the activated sludge participated in UFA biosynthesis, and γ-Linolenic could be converted to Arachidonic acid at low temperature. The highly UFA biosynthesis in activated sludge was n-6 highly UFA biosynthesis, rather than n-3 highly UFA biosynthesis. The microbial community structures of activated sludge were analyzed by PLFA and high-throughput sequencing (HiSeq) simultaneously. Acidovorax, Pseudomonas, Flavobacterium and Polaromonas occupied higher percentage at 5°C, and genetic changes of highly UFA biosynthesis derived from microbial community structures change. Copyright © 2016. Published by Elsevier Ltd.

  7. Change in digestibility of gamma-irradiated starch by low temperature cooking

    International Nuclear Information System (INIS)

    Kume, T.; Ishigaki, I.; Rahman, S.


    Combination effect of irradiation and low temperature cooking on starch digestibility has been investigated as a basic research for application of radiosterilization on starch fermentation. The digestion of corn starch by glucoamylase after cooking at low temperature was enhanced by γ-irradiation and the required cooking temperature was decreased from 75-80 0 C to 65 0 C by 25 kGy. Gelatinization of starches except tapioca starch was enhanced by irradiation and it corresponds to the digestibility. The digestibility of potato starch which has a high viscosity was especially enhanced at low temperature cooking because the viscosity was markedly decreased by irradiation. These results show that the irradiation of starches is useful not only for the sterilization of fermentation broth but also for the enhancement of digestion. (orig.) [de

  8. The performance of a residential heat pump operating with a nonazeotropic binary refrigerant mixture (United States)

    Didion, D.; Mulroy, W.

    Results of laboratory measurement of the performance change of a substantially unmodified residential heat pump designed for 222 when charged with a non azeotropic, binary mixture of R1381 and R152a is presented. Results are presented for various sizes of fixed expansion devices. The effect of gliding temperature in the saturation zone was found to be small. The effect of compositions shift by flash distillation in the accumulator was found to measurably improve low temperature heating performance. It was further observed that some system modification (such as the addition of a receiver) could have further enhanced this low temperature heating performance improvement.

  9. Functional analysis of lipid metabolism genes in wine yeasts during alcoholic fermentation at low temperature

    Directory of Open Access Journals (Sweden)

    María López-Malo


    Full Text Available Wine produced by low-temperature fermentation is mostly considered to have improved sensory qualities. However few commercial wine strains available on the market are well-adapted to ferment at low temperature (10 – 15°C. The lipid metabolism of Saccharomyces cerevisiae plays a central role in low temperature adaptation. One strategy to modify lipid composition is to alter transcriptional activity by deleting or overexpressing the key genes of lipid metabolism. In a previous study, we identified the genes of the phospholipid, sterol and sphingolipid pathways, which impacted on growth capacity at low temperature. In the present study, we aimed to determine the influence of these genes on fermentation performance and growth during low-temperature wine fermentations. We analyzed the phenotype during fermentation at the low and optimal temperature of the lipid mutant and overexpressing strains in the background of a derivative commercial wine strain. The increase in the gene dosage of some of these lipid genes, e.g., PSD1, LCB3, DPL1 and OLE1, improved fermentation activity during low-temperature fermentations, thus confirming their positive role during wine yeast adaptation to cold. Genes whose overexpression improved fermentation activity at 12°C were overexpressed by chromosomal integration into commercial wine yeast QA23. Fermentations in synthetic and natural grape must were carried out by this new set of overexpressing strains. The strains overexpressing OLE1 and DPL1 were able to finish fermentation before commercial wine yeast QA23. Only the OLE1 gene overexpression produced a specific aroma profile in the wines produced with natural grape must.

  10. Biomedical Applications of Low Temperature Atmospheric Pressure Plasmas to Cancerous Cell Treatment and Tooth Bleaching (United States)

    Lee, Jae Koo; Kim, Myoung Soo; Byun, June Ho; Kim, Kyong Tai; Kim, Gyoo Cheon; Park, Gan Young


    Low temperature atmospheric pressure plasmas have attracted great interests and they have been widely applied to biomedical applications to interact with living tissues, cells, and bacteria due to their non-thermal property. This paper reviews the biomedical applications of low temperature atmospheric pressure plasmas to cancerous cell treatment and tooth bleaching. Gold nanoparticles conjugated with cancer-specific antibodies have been introduced to cancerous cells to enhance selective killing of cells, and the mechanism of cell apoptosis induced by plasma has been investigated. Tooth exposed to helium plasma jet with hydrogen peroxide has become brighter and the productions of hydroxyl radicals from hydrogen peroxide have been enhanced by plasma exposure.

  11. Computer simulation of low-temperature composites sintering processes for additive technologies (United States)

    Tovpinets, A. O.; Leytsin, V. N.; Dmitrieva, M. A.


    This is impact research of mixture raw components characteristics on the low-temperature composites structure formation during the sintering process. The obtained results showed that the structure determination of initial compacts obtained after thermal destruction of the polymer binder lets quantify the concentrations of main components and the refractory crystalline product of thermal destruction. Accounting for the distribution of thermal destruction refractory product allows us to refine the forecast of thermal stresses in the matrix of sintered composite. The presented results can be considered as a basis for optimization of initial compositions of multilayer low-temperature composites obtained by additive technologies.

  12. On the nature of low temperature anomalies of metallic glass inelastic properties

    International Nuclear Information System (INIS)

    Spivak, L.V.; Khonik, V.A.


    Low-temperature (30 60 Nb 40 metallic glass (MG) exposed to the preliminary cold deformation via rolling, to high-temperature homogeneous deformation or to electrolytic hydrogen absorption were investigated. Conclusion is made that the published low-temperature peaks of the internal friction in quick-hardened cold-deformed or hydrogen absorbed MGs are of the common dislocation-like nature. Effect of 2 MeV electron irradiation on the temperature dependence of the internal friction and on the elasticity module of hydrogenated specimens was investigated, as well [ru

  13. Performance of ultra low temperature district heating systems with utility plant and booster heat pumps

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Thorsen, Jan Eric; Markussen, Wiebke Brix


    The optimal integration of booster heat pumps in ultra low temperature district heating (ULTDH) was investigated and compared to the performance of low temperature district heating. Two possible heat production technologies for the DH networks were analysed, namely extraction combined heat...... and power (CHP) and central heat pumps (HPs). The analysis focussed on the characteristic heat demands of newly build multi-story buildings and the results were based on the ratio of the individual demands compared to the total. It was found that the optimal return temperature was dependent on the forward...

  14. The Use of Low Temperature Detectors for Direct Measurements of the Mass of the Electron Neutrino

    Directory of Open Access Journals (Sweden)

    A. Nucciotti


    Full Text Available Recent years have witnessed many exciting breakthroughs in neutrino physics. The detection of neutrino oscillations has proved that neutrinos are massive particles, but the assessment of their absolute mass scale is still an outstanding challenge in today particle physics and cosmology. Since low temperature detectors were first proposed for neutrino physics experiments in 1984, there has been tremendous technical progress: today this technique offers the high energy resolution and scalability required to perform competitive experiments challenging the lowest electron neutrino masses. This paper reviews the thirty-year effort aimed at realizing calorimetric measurements with sub-eV neutrino mass sensitivity using low temperature detectors.

  15. High pressure neutron and X-ray diffraction at low temperatures

    International Nuclear Information System (INIS)

    Ridley, Christopher J.; Kamenev, Konstantin V.


    This paper presents a review of techniques and considerations in the design and construction of high pressure, low temperature diffraction experiments. Also intended as an introductory text to new high pressure users, the crucial aspects of pressure cell design are covered. The general classification of common designs, and a discussion into the key beam interaction, mechanical, and thermal properties of commonly used materials is given. The advantages of different materials and high pressure cell classifications are discussed, and examples of designs developed for low temperature diffraction studies are presented, and compared. (orig.)

  16. Low-temperature structural phase transition in deuterated and protonated lithium acetate dihydrate

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, F., E-mail: schroeder@kristall.uni-frankfurt.d [Goethe-Universitaet Frankfurt am Main, Institut fuer Geowissenschaften, Abt. Kristallographie, Altenhoeferallee 1, 60438 Frankfurt am Main (Germany); Winkler, B.; Haussuehl, E. [Goethe-Universitaet Frankfurt am Main, Institut fuer Geowissenschaften, Abt. Kristallographie, Altenhoeferallee 1, 60438 Frankfurt am Main (Germany); Cong, P.T.; Wolf, B. [Goethe-Universitaet Frankfurt am Main, Physikalisches Institut, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Avalos-Borja, M. [Instituto Potosino de Investigacion Cientifica y Tecnologica, A.C. Camino a la Presa San Jose 2055, Col. Lomas 4 seccion CP 78216, San Luis Potosi (Mexico); Quilichini, M.; Hennion, B. [Laboratoire Leon Brillouin, CEN Saclay, 91191 Gif-sur-Yvette (France)


    Heat capacity measurements of protonated lithium acetate dihydrate show a structural phase transition at T = 12 K. This finding is in contrast to earlier work, where it was thought that only the deuterated compound undergoes a low temperature structural phase transition. This finding is confirmed by low temperature ultrasound spectroscopy, where the structural phase transition is associated with a velocity decrease of the ultrasonic waves, i.e. with an elastic softening. We compare the thermodynamic properties of the protonated and deuterated compounds and discuss two alternatives for the mechanism of the phase transition based on the thermal expansion measurements.

  17. Destruction of α-synuclein based amyloid fibrils by a low temperature plasma jet (United States)

    Karakas, Erdinc; Munyanyi, Agatha; Greene, Lesley; Laroussi, Mounir


    Amyloid fibrils are ordered beta-sheet aggregates that are associated with a number of neurodegenerative diseases such as Alzheimer and Parkinson. At present, there is no cure for these progressive and debilitating diseases. Here we report initial studies that indicate that low temperature atmospheric pressure plasma can break amyloid fibrils into smaller units in vitro. The plasma was generated by the "plasma pencil," a device capable of emitting a long, low temperature plasma plume/jet. This avenue of research may facilitate the development of a plasma-based medical treatment.

  18. Destruction of α-synuclein based amyloid fibrils by a low temperature plasma jet

    International Nuclear Information System (INIS)

    Karakas, Erdinc; Laroussi, Mounir; Munyanyi, Agatha; Greene, Lesley


    Amyloid fibrils are ordered beta-sheet aggregates that are associated with a number of neurodegenerative diseases such as Alzheimer and Parkinson. At present, there is no cure for these progressive and debilitating diseases. Here we report initial studies that indicate that low temperature atmospheric pressure plasma can break amyloid fibrils into smaller units in vitro. The plasma was generated by the 'plasma pencil', a device capable of emitting a long, low temperature plasma plume/jet. This avenue of research may facilitate the development of a plasma-based medical treatment.

  19. Experimental study of the use of probe methods for diagnostic of low-temperature magnetized plasma


    Zanáška, Michal


    The ball-pen probe is a relatively new diagnostic method, that has been designed for direct measurement of plasma potential in magnetized plasmas. Nowadays, it is routinely used at several high-temperature plasma devices in Europe and it has been tested also in conditions of low-temperature plasma, which are substantially different from that of high-temperature plasma. The measurements performed so far showed, that ball-pen probe could be used also in low-temperature plasma. However, more mea...

  20. Growth Mechanism for Low Temperature PVD Graphene Synthesis on Copper Using Amorphous Carbon (United States)

    Narula, Udit; Tan, Cher Ming; Lai, Chao Sung


    Growth mechanism for synthesizing PVD based Graphene using Amorphous Carbon, catalyzed by Copper is investigated in this work. Different experiments with respect to Amorphous Carbon film thickness, annealing time and temperature are performed for the investigation. Copper film stress and its effect on hydrogen diffusion through the film grain boundaries are found to be the key factors for the growth mechanism, and supported by our Finite Element Modeling. Low temperature growth of Graphene is achieved and the proposed growth mechanism is found to remain valid at low temperatures.