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Sample records for cryogenic conditions analogous

  1. High field conditioning of cryogenic RF cavities

    International Nuclear Information System (INIS)

    Cole, M.; Debiak, T.; Lom, C.; Shephard, W.; Sredniawski, J.

    1993-01-01

    Space-based and other related accelerators have conditioning and operation requirements that are not found in most machines. The use of cryogenic copper, relatively poor vacuum, and limited power storage and operating time put unusual demands on the high-field conditioning process and present some concerns. Two CW cryogenic engineering model open-quotes sparkerclose quotes cavities have been fabricated and tested to fairly high field levels. Tests included initial and repeated conditioning as well as sustained RF operations. The two cavities were an engineering model TDL and an engineering model RFQ. Both cavities operated at 425 MHz. The DTL was conditioned to 46 MV/m at 100% duty factor (CW) at cryogenic temperature. This corresponds to a gap voltage of 433 kV and a real estate accelerating gradient (energy gain/total cavity length) of 6.97 MV/m. The authors believe this to be record performance for cryo CW operation. During cryo pulsed operation, the same cavity reached 48 MV/m with 200 μsec pulses at 0.5% DF. The RFQ was conditioned to 30 MV/m CW at cryo, 85 kV gap voltage. During a brief period of cryo pulsed operation, the RFQ operated at 46 MV/m, or 125 kV gap voltage. Reconditioning experiments were performed on both cavities and no problems were encountered. It should be noted that the vacuum levels were not very stringent during these tests and no special cleanliness or handling procedures were followed. The results of these tests indicate that cavities can run CW without difficulty at cryogenic temperatures at normal conservative field levels. Higher field operation may well be possible, and if better vacuums are used and more attention is paid to cleanliness, much higher fields may be attainable

  2. Cryogenic Calcite: A Morphologic and Isotopic Analog to the ALH84001 Carbonates

    Science.gov (United States)

    Niles, P. B.; Leshin, L. A.; Socki, R. A.; Guan, Y.; Ming, D. W.; Gibson, E. K.

    2004-01-01

    Martian meteorite ALH84001 carbonates preserve large and variable microscale isotopic compositions, which in some way reflect their formation environment. These measurements show large variations (>20%) in the carbon and oxygen isotopic compositions of the carbonates on a 10-20 micron scale that are correlated with chemical composition. However, the utilization of these data sets for interpreting the formation conditions of the carbonates is complex due to lack of suitable terrestrial analogs and the difficulty of modeling under non-equilibrium conditions. Thus, the mechanisms and processes are largely unknown that create and preserve large microscale isotopic variations in carbonate minerals. Experimental tests of the possible environments and mechanisms that lead to large microscale isotopic variations can help address these concerns. One possible mechanism for creating large carbon isotopic variations in carbonates involves the freezing of water. Carbonates precipitate during extensive CO2 degassing that occurs during the freezing process as the fluid s decreasing volume drives CO2 out. This rapid CO2 degassing results in a kinetic isotopic fractionation where the CO2 gas has a much lighter isotopic composition causing an enrichment of 13C in the remaining dissolved bicarbonate. This study seeks to determine the suitability of cryogenically formed carbonates as analogs to ALH84001 carbonates. Specifically, our objective is to determine how accurately models using equilibrium fractionation factors approximate the isotopic compositions of cryogenically precipitated carbonates. This includes determining the accuracy of applying equilibrium fractionation factors during a kinetic process, and determining how isotopic variations in the fluid are preserved in microscale variations in the precipitated carbonates.

  3. Cryogenics

    International Nuclear Information System (INIS)

    Shukla, R.K.

    1990-01-01

    Cryogenics refers to the coldest area known in nature. This temperature range has an upper limit arbitrarily defined as -100 degrees C (-250 degrees C by some) and a lower limit of absolute zero. These limits separate it from the temperature range generally used in refrigerating engineering. One important application of cryogenics is the separation ad purification of air into its various components (oxygen, nitrogen, argon, and the rare gases). Other important developments have been the large-scale production of liquid hydrogen; helium extraction from natural gas; storage and transport of liquefied gases such as oxygen, argon, nitrogen, helium, neon, xenon, and hydrogen; liquefaction of natural gas for ocean transport and peak shaving; and many new types of cryogenic refrigeration devices. This paper introduces the topic of cryogenic engineering. Cryogenic processes generally range from ambient conditions to the boiling point of the cryogenic fluid. Cryogenic cycles also incorporate two or more pressure levels. These properties must also cover the vapor, vapor-liquid, and sometimes the solid regions. Therefore, the physical properties of fluids over a great range of temperatures and pressures must be known. Solubility of contaminants must be known in order to design for their removal. The main physical properties for design purposes are those usually used in unit operations, such as fluid flow, heat transfer, and the like, in addition to those directly related to the Joule-Thomson effect and expansion work. Properties such as density, viscosity, thermal conductivity, heat capacity, enthalpy, entropy, vapor pressure, and vapor-liquid equilibriums are generally obtained in graphical, tabular, or equation form, as a function of temperature and pressure

  4. Photoionization in Ultraviolet Processing of Astrophysical Ice Analogs at Cryogenic Temperatures

    Science.gov (United States)

    Woon, David E.

    2004-01-01

    Two recent experimental studies have demonstrated that amino acids or amino acid precursors are generated when astrophysical ice analogs are subjected to ultraviolet (UV) irradiation at cryogenic temperatures. Understanding the complete phenomenology of photoprocessing is critical to elucidating chemical reaction mechanisms that can function within an ice matrix under very cold conditions. Pushing beyond the much better characterized study of photolytic dissociation of chemical bonds through electronic excitation, this work explored the ability of UV radiation present in the interstellar medium to ionize small molecules embedded in ices. Quantum chemical calculations, including bulk solvation effects, were used to study the ionization of hydrogen (H2), water, and methanol (CH3OH) bound in small clusters of water. Ionization potentials were found to be much smaller in the condensed phase than in the gas phase; even a small cluster can account for large changes in the ionization potentials in ice, as well as the known formation of an OH--H3O+ pair in the case of H2O photoionization. To gauge the impact of photoionization on subsequent grain chemistry, the reaction between OH and CO in the presence of H3O+ was studied and compared with the potential energy surface without hydronium present, which is relevant to chemistry following photolysis. The differences indicate that the reaction is somewhat more likely to proceed to products (H + CO2) in the case of photoionization.

  5. Cryogenics

    International Nuclear Information System (INIS)

    Fradkov, A.B.

    1991-01-01

    The application of cryogenics in various areas of science and technology is related in a popular way. Utilization of cryogenics in the following production processes is described: separation of air, gas mixtures; production of helium; separation of hydrogen isotopes; production of deuterium. Applications of cryogenics in refrigerating engineering, superconductivity and high-energy physics, controlled thermonuclear fusion, superconducting electric motors and electric energy storages are considered

  6. Cryogenics

    International Nuclear Information System (INIS)

    Gutierrez R, C.; Jimenez D, J.; Cejudo A, J.; Hernandez M, V.

    1997-01-01

    Cryogenics is one of these technologies which contributes to scientific research that supports to the industry in the following benefits: 1. Storage ability and a great quantity of dense gases with cryogenic liquid which is found at high pressure. 2. Production ability at low cost with high purity gases through distillation or condensation. 3. Ability to use low temperatures in the refrigerating materials or alteration of the physical properties. This technology is used for reprocessing of those short and long half life radioactive wastes which always have been required that to be separated with classical methods. In this text we report the radioactive wastes separation by more sophisticated methods but more quickly and reliable. (Author)

  7. Deep Cryogenic Low Power 24 Bits Analog to Digital Converter with Active Reverse Cryostat

    Science.gov (United States)

    Turqueti, Marcos; Prestemon, Soren; Albright, Robert

    LBNL is developing an innovative data acquisition module for superconductive magnets where the front-end electronics and digitizer resides inside the cryostat. This electronic package allows conventional electronic technologies such as enhanced metal-oxide-semiconductor to work inside cryostats at temperatures as low as 4.2 K. This is achieved by careful management of heat inside the module that keeps the electronic envelop at approximately 85 K. This approach avoids all the difficulties that arise from changes in carrier mobility that occur in semiconductors at deep cryogenic temperatures. There are several advantages in utilizing this system. A significant reduction in electrical noise from signals captured inside the cryostat occurs due to the low temperature that the electronics is immersed in, reducing the thermal noise. The shorter distance that signals are transmitted before digitalization reduces pickup and cross-talk between channels. This improved performance in signal-to-noise rate by itself is a significant advantage. Another important advantage is the simplification of the feedthrough interface on the cryostat head. Data coming out of the cryostat is digital and serial, dramatically reducing the number of lines going through the cryostat feedthrough interface. It is important to notice that all lines coming out of the cryostat are digital and low voltage, reducing the possibility of electric breakdown inside the cryostat. This paper will explain in details the architecture and inner workings of this data acquisition system. It will also provide the performance of the analog to digital converter when the system is immersed in liquid helium, and in liquid nitrogen. Parameters such as power dissipation, integral non-linearity, effective number of bits, signal-to-noise and distortion, will be presented for both temperatures.

  8. Investigating the effects of critical phenomena in premixed methane-oxygen flames at cryogenic conditions

    Science.gov (United States)

    Gopal, Abishek; Yellapantula, Shashank; Larsson, Johan

    2017-11-01

    Methane is increasingly becoming viable as a rocket fuel in the latest generation of launch vehicles. In liquid rocket engines, fuel and oxidizer are injected under cryogenic conditions into the combustion chamber. At high pressures, typical of rocket combustion chambers, the propellants exist in supercritical states where the ideal gas thermodynamics are no longer valid. We investigate the effects of real-gas thermodynamics on transcritical laminar premixed methane-oxygen flames. The effect of the real-gas cubic equations of state and high-pressure transport properties on flame dynamics is presented. We also study real-gas effects on the extinction limits of the methane-oxygen flame.

  9. Criterion for burn-up conditions in gas-cooled cryogenic current leads

    International Nuclear Information System (INIS)

    Bejan, A.; Cluss, E.M. Jr.

    1976-01-01

    Superconducting magnets are energized through helium vapour-cooled cryogenic current leads operating at high ratios of current to mass flow. The high current operation where lead temperature, runaway, and eventual burn-up are likely to occur is investigated. A simple criterion for estimating the burn-up operation conditions (current, mass flow) for a given lead geometry (cross-sectional area, length, heat exchanger area) is presented. This article stresses the role played by the available heat exchanger area in avoiding burn-up at high ratios of current to mass flow. (author)

  10. Surface Characteristics of Machined NiTi Shape Memory Alloy: The Effects of Cryogenic Cooling and Preheating Conditions

    Science.gov (United States)

    Kaynak, Y.; Huang, B.; Karaca, H. E.; Jawahir, I. S.

    2017-07-01

    This experimental study focuses on the phase state and phase transformation response of the surface and subsurface of machined NiTi alloys. X-ray diffraction (XRD) analysis and differential scanning calorimeter techniques were utilized to measure the phase state and the transformation response of machined specimens, respectively. Specimens were machined under dry machining at ambient temperature, preheated conditions, and cryogenic cooling conditions at various cutting speeds. The findings from this research demonstrate that cryogenic machining substantially alters austenite finish temperature of martensitic NiTi alloy. Austenite finish ( A f) temperature shows more than 25 percent increase resulting from cryogenic machining compared with austenite finish temperature of as-received NiTi. Dry and preheated conditions do not substantially alter austenite finish temperature. XRD analysis shows that distinctive transformation from martensite to austenite occurs during machining process in all three conditions. Complete transformation from martensite to austenite is observed in dry cutting at all selected cutting speeds.

  11. Review on plasmas in extraordinary media: plasmas in cryogenic conditions and plasmas in supercritical fluids

    Science.gov (United States)

    Stauss, Sven; Muneoka, Hitoshi; Terashima, Kazuo

    2018-02-01

    Plasma science and technology has enabled advances in very diverse fields: micro- and nanotechnology, chemical synthesis, materials fabrication and, more recently, biotechnology and medicine. While many of the currently employed plasma tools and technologies are very advanced, the types of plasmas used in micro- and nanofabrication pose certain limits, for example, in treating heat-sensitive materials in plasma biotechnology and plasma medicine. Moreover, many physical properties of plasmas encountered in nature, and especially outer space, i.e. very-low-temperature plasmas or plasmas that occur in high-density media, are not very well understood. The present review gives a short account of laboratory plasmas generated under ’extreme’ conditions: at cryogenic temperatures and in supercritical fluids. The fundamental characteristics of these cryogenic plasmas and cryoplasmas, and plasmas in supercritical fluids, especially supercritical fluid plasmas, are presented with their main applications. The research on such exotic plasmas is expected to lead to further understanding of plasma physics and, at the same time, enable new applications in various technological fields.

  12. Methods and Piezoelectric Imbedded Sensors for Damage Detection in Composite Plates Under Ambient and Cryogenic Conditions

    Science.gov (United States)

    Engberg, Robert; Ooi, Teng K.

    2004-01-01

    New methods for structural health monitoring are being assessed, especially in high-performance, extreme environment, safety-critical applications. One such application is for composite cryogenic fuel tanks. The work presented here attempts to characterize and investigate the feasibility of using imbedded piezoelectric sensors to detect cracks and delaminations under cryogenic and ambient conditions. A variety of damage detection methods and different Sensors are employed in the different composite plate samples to aid in determining an optimal algorithm, sensor placement strategy, and type of imbedded sensor to use. Variations of frequency, impedance measurements, and pulse echoing techniques of the sensors are employed and compared. Statistical and analytic techniques are then used to determine which method is most desirable for a specific type of damage. These results are furthermore compared with previous work using externally mounted sensors. Results and optimized methods from this work can then be incorporated into a larger composite structure to validate and assess its structural health. This could prove to be important in the development and qualification of any 2" generation reusable launch vehicle using composites as a structural element.

  13. Flow Visualization at Cryogenic Conditions Using a Modified Pressure Sensitive Paint Approach

    Science.gov (United States)

    Watkins, A. Neal; Goad, William K.; Obara, Clifford J.; Sprinkle, Danny R.; Campbell, Richard L.; Carter, Melissa B.; Pendergraft, Odis C., Jr.; Bell, James H.; Ingram, JoAnne L.; Oglesby, Donald M.

    2005-01-01

    A modification to the Pressure Sensitive Paint (PSP) method was used to visualize streamlines on a Blended Wing Body (BWB) model at full-scale flight Reynolds numbers. In order to achieve these conditions, the tests were carried out in the National Transonic Facility operating under cryogenic conditions in a nitrogen environment. Oxygen is required for conventional PSP measurements, and several tests have been successfully completed in nitrogen environments by injecting small amounts (typically < 3000 ppm) of oxygen into the flow. A similar technique was employed here, except that air was purged through pressure tap orifices already existent on the model surface, resulting in changes in the PSP wherever oxygen was present. The results agree quite well with predicted results obtained through computational fluid dynamics analysis (CFD), which show this to be a viable technique for visualizing flows without resorting to more invasive procedures such as oil flow or minitufts.

  14. Proposed Method for the Verification of the LHC Bus Bar Splices during Commissioning at Cryogenic Conditions

    CERN Document Server

    Calvi, M; Rodríguez-Mateos, F

    2007-01-01

    The commissioning of the Large Hadron Collider at CERN includes the powering of about 1600 superconducting electrical circuits to currents ranging from 55 A to 11.8 kA. A large number of splices (over 70'000) are present at the magnet interconnects, which can only be validated with current at cryogenic conditions. This paper discusses the thermal effects related to possible faulty splices during the powering of the circuits. The calculations of the quench and detection currents, as well as the hot spot temperatures, are described. The heat transfer model with the surrounding coolant and the current profiles inside the splices are presented. This study is completed with a sensitivity analysis on the hot spot temperature with respect to the model parameters. Finally, the implications with respect to the powering ramps and parameters to be applied during the first powering are discussed.

  15. Chip formation in turning S45C medium carbon steel in cryogenic conditions

    Directory of Open Access Journals (Sweden)

    Jaharah A. Ghani

    2017-09-01

    Full Text Available This paper presents the tribology issue regarding the chip formation in machining medium carbon steel (S45C using a coated and uncoated carbide tools. The machining parameters under investigation were cutting speed, feed rate, and depth of cut under dry and cryogenic cutting condition using coated and uncoated carbide tools. The chip shape was largely depended on the combination of machining parameters, especially at high depth of cut and feed rate; the favorable chip was produced. Larger value of shear angle results in smaller shear plane area that provides benefits of lower cutting force needed to shear off the chips and lower cutting temperature being generated during the machining process.

  16. Numerical investigation on cryogenic liquid jet under transcritical and supercritical conditions

    Science.gov (United States)

    Li, Liang; Xie, Maozhao; Wei, Wu; Jia, Ming; Liu, Hongsheng

    2018-01-01

    Cryogenic fluid injection and mixing under transcritical and supercritical conditions is numerically investigated with emphasis on the difference of the mechanism and characteristics between the two injections. A new solver is developed which is capable of handling the nonideality of the equation of state and the anomalies in fluid transport properties and is incorporated into the CFD software OpenFOAM. The new solver has been validated against available experimental data and exhibits a good performance. Computational results indicates that the differences between transcritical and supercritical injections are mainly induced by the pseudo-boiling phenomenon, resulting in that the transcritical jet has a longer cold liquid core and an isothermal expansion occurs at the surface of the cold core. The thickness of the supercritical mixing layer and its increase value along the jet direction are greater than its transcritical counterpart. The high-temperature jet whose initial temperature is above the pseudo-boiling temperature has the ability of enhancing the mixing of the jet with the surrounding gas.

  17. Boundary-Layer Detection at Cryogenic Conditions Using Temperature Sensitive Paint Coupled with a Carbon Nanotube Heating Layer

    Science.gov (United States)

    Goodman, Kyle Z.; Lipford, William E.; Watkins, Anthony Neal

    2016-01-01

    Detection of flow transition on aircraft surfaces and models can be vital to the development of future vehicles and computational methods for evaluating vehicle concepts. In testing at ambient conditions, IR thermography is ideal for this measurement. However, for higher Reynolds number testing, cryogenic facilities are often used, in which IR thermography is difficult to employ. In these facilities, temperature sensitive paint is an alternative with a temperature step introduced to enhance the natural temperature change from transition. Traditional methods for inducing the temperature step by changing the liquid nitrogen injection rate often change the tunnel conditions. Recent work has shown that adding a layer consisting of carbon nanotubes to the surface can be used to impart a temperature step on the model surface with little change in the operating conditions. Unfortunately, this system physically degraded at 130 K and lost heating capability. This paper describes a modification of this technique enabling operation down to at least 77 K, well below the temperature reached in cryogenic facilities. This is possible because the CNT layer is in a polyurethane binder. This was tested on a Natural Laminar Flow model in a cryogenic facility and transition detection was successfully visualized at conditions from 200 K to 110 K. Results were also compared with the traditional temperature step method.

  18. Boundary-Layer Detection at Cryogenic Conditions Using Temperature Sensitive Paint Coupled with a Carbon Nanotube Heating Layer

    Directory of Open Access Journals (Sweden)

    Kyle Z. Goodman

    2016-12-01

    Full Text Available Detection of flow transition on aircraft surfaces and models can be vital to the development of future vehicles and computational methods for evaluating vehicle concepts. In testing at ambient conditions, IR thermography is ideal for this measurement. However, for higher Reynolds number testing, cryogenic facilities are often used, in which IR thermography is difficult to employ. In these facilities, temperature sensitive paint is an alternative with a temperature step introduced to enhance the natural temperature change from transition. Traditional methods for inducing the temperature step by changing the liquid nitrogen injection rate often change the tunnel conditions. Recent work has shown that adding a layer consisting of carbon nanotubes to the surface can be used to impart a temperature step on the model surface with little change in the operating conditions. Unfortunately, this system physically degraded at 130 K and lost heating capability. This paper describes a modification of this technique enabling operation down to at least 77 K, well below the temperature reached in cryogenic facilities. This is possible because the CNT layer is in a polyurethane binder. This was tested on a Natural Laminar Flow model in a cryogenic facility and transition detection was successfully visualized at conditions from 200 K to 110 K. Results were also compared with the traditional temperature step method.

  19. Survival of the insulator under the electrical stress condition at cryogenic temperature

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Seung Myeong [Dept. of Fire Protection Engineering, Changwon Moonsung University, Changwon (Korea, Republic of); Kim, Sang Hyun [Dept. of Electrical Engineering, Gyeongsang National University, Jinju (Korea, Republic of)

    2013-12-15

    We have clearly investigated with respect to the survival of the insulator at cryogenic temperature under the electrical stress. The breakdown and voltage-time characteristics of turn-to-turn models for point contact geometry and surface contact geometry using copper multi wrapped with polyimide film for an HTS transformer were investigated under AC and impulse voltage at 77 K. Polyimide film (Kapton) 0.025 mm thick is used for multi wrapping of the electrode. As expected, the breakdown voltages for the surface contact geometry are lower than that of the point contact geometry, because the contact area of the surface contact geometry is lager than that of the point contact geometry. The time to breakdown t50 decreases as the applied voltage is increased, and the lifetime indices increase slightly as the number of layers is increased. The electric field amplitude at the position where breakdown occurs is about 80% of the maximum electric field value. The relationship between survival probability and the electrical stress at cryogenic temperature was evident.

  20. Cryogenics safety

    International Nuclear Information System (INIS)

    Reider, R.

    1977-01-01

    The safety hazards associated with handling cryogenic fluids are discussed in detail. These hazards include pressure buildup when a cryogenic fluid is heated and becomes a gas, potential damage to body tissues due to surface contact, toxic risk from breathing air altered by cryogenic fluids, dangers of air solidification, and hazards of combustible cryogens such as liquified oxygen, hydrogen, or natural gas or of combustible mixtures. Safe operating procedures and emergency planning are described

  1. Fiber Bragg Grating Dilatometry in Extreme Magnetic Field and Cryogenic Conditions

    Directory of Open Access Journals (Sweden)

    Marcelo Jaime

    2017-11-01

    Full Text Available In this work, we review single mode SiO2 fiber Bragg grating techniques for dilatometry studies of small single-crystalline samples in the extreme environments of very high, continuous, and pulsed magnetic fields of up to 150 T and at cryogenic temperatures down to <1 K. Distinct millimeter-long materials are measured as part of the technique development, including metallic, insulating, and radioactive compounds. Experimental strategies are discussed for the observation and analysis of the related thermal expansion and magnetostriction of materials, which can achieve a strain sensitivity (ΔL/L as low as a few parts in one hundred million (≈10−8. The impact of experimental artifacts, such as those originating in the temperature dependence of the fiber’s index of diffraction, light polarization rotation in magnetic fields, and reduced strain transfer from millimeter-long specimens, is analyzed quantitatively using analytic models available in the literature. We compare the experimental results with model predictions in the small-sample limit, and discuss the uncovered discrepancies.

  2. Formation of a new benzene-ethane co-crystalline structure under cryogenic conditions.

    Science.gov (United States)

    Vu, Tuan Hoang; Cable, Morgan L; Choukroun, Mathieu; Hodyss, Robert; Beauchamp, Patricia

    2014-06-12

    We report the first experimental finding of a solid molecular complex between benzene and ethane, two small apolar hydrocarbons, at atmospheric pressure and cryogenic temperatures. Considerable amounts of ethane are found to be incorporated inside the benzene lattice upon the addition of liquid ethane onto solid benzene at 90-150 K, resulting in formation of a distinctive co-crystalline structure that can be detected via micro-Raman spectroscopy. Two new features characteristic of these co-crystals are observed in the Raman spectra at 2873 and 1455 cm(-1), which are red-shifted by 12 cm(-1) from the υ1 (a1g) and υ11 (eg) stretching modes of liquid ethane, respectively. Analysis of benzene and ethane vibrational bands combined with quantum mechanical modeling of isolated molecular dimers reveal an interaction between the aromatic ring of benzene and the hydrogen atoms of ethane in a C-H···π fashion. The most favored configuration for the benzene-ethane dimer is the monodentate-contact structure, with a calculated interaction energy of 9.33 kJ/mol and an equilibrium bonding distance of 2.66 Å. These parameters are comparable to those for a T-shaped co-crystalline complex between benzene and acetylene that has been previously reported in the literature. These results are relevant for understanding the hydrocarbon cycle of Titan, where benzene and similar organics may act as potential hydrocarbon reservoirs due to this incorporation mechanism.

  3. Helium cryogenics

    CERN Document Server

    Van Sciver, Steven W

    2012-01-01

    Twenty five years have elapsed since the original publication of Helium Cryogenics. During this time, a considerable amount of research and development involving helium fluids has been carried out culminating in several large-scale projects. Furthermore, the field has matured through these efforts so that there is now a broad engineering base to assist the development of future projects. Helium Cryogenics, 2nd edition brings these advances in helium cryogenics together in an updated form. As in the original edition, the author's approach is to survey the field of cryogenics with emphasis on helium fluids. This approach is more specialized and fundamental than that contained in other cryogenics books, which treat the associated range of cryogenic fluids. As a result, the level of treatment is more advanced and assumes a certain knowledge of fundamental engineering and physics principles, including some quantum mechanics. The goal throughout the work is to bridge the gap between the physics and engineering aspe...

  4. Cryogenic exciter

    Science.gov (United States)

    Bray, James William [Niskayuna, NY; Garces, Luis Jose [Niskayuna, NY

    2012-03-13

    The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.

  5. Comparison of pore water samplers and cryogenic distillation under laboratory and field conditions for soil water stable isotope analysis.

    Science.gov (United States)

    Thoma, Michael; Frentress, Jay; Tagliavini, Massimo; Scandellari, Francesca

    2018-02-15

    We used pore water samplers (PWS) to sample for isotope analysis (1) only water, (2) soil under laboratory conditions, and (3) soil in the field comparing the results with cryogenic extraction (CE). In (1) and (2), no significant differences between source and water extracted with PWS were detected with a mean absolute difference (MAD) always lower than 2 ‰ for δ 2 H and 1 ‰ for δ 18 O. In (2), CE water was more enriched than PWS-extracted water, with a MAD respect to source water of roughly 8 ‰ for δ 2 H and 4 ‰ for δ 18 O. In (3), PWS water was enriched relative to CE water by 3 ‰ for δ 2 H and 0.9 ‰ for δ 18 O. The latter result may be due to the distinct water portions sampled by the two methods. Large pores, easily sampled by PWS, likely retain recent, and enriched, summer precipitation while small pores, only sampled by CE, possibly retain isotopically depleted water from previous winter precipitation or irrigation inputs. Accuracy and precision were greater for PWS relative to CE. PWS is therefore suggested as viable tool to extract soil water for stable isotope analysis, particularly for soils used in this study (sandy and silty loams).

  6. Surface Tension Confines Cryogenic Liquid

    Science.gov (United States)

    Castles, Stephen H.; Schein, Michael E.

    1989-01-01

    New type of Dewar provides passive, constant-temperature cryogenic cooling for scientific instruments under normal-to low-gravity conditions. Known as Surface-Tension-Contained Liquid Cryogen Cooler (STCLCC), keeps liquid cryogen in known location inside the Dewar by trapping liquid inside spongelike material. Unique sponge material fills most of volume of inner tank. Sponge is all-silica, open-cell material similar to that used for Space Shuttle thermal-protection tiles.

  7. Analogy between soap film and gas dynamics. I. Equations and shock jump conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wen, C.Y.; Lai, J.Y. [Department of Mechanical Engineering, Da-Yeh University, Chang-Hwa (Taiwan)

    2003-01-01

    The governing equations of compressible flows in soap films are formulated based on the very specific property equations of soap films. The basic normal shock relations and the Rankine-Hugoniot equation are derived for steady one-dimensional flows in soap films. The results are similar to those of compressible gases. The analogy between compressible flows in soap films and that in gases is discussed. On short time scales, the dynamic response of the film is characterized by the Marangoni elasticity, and soap films are shown to be analogous to compressible gases with a specific heat ratio of {gamma}=1.0. Results for Gibbs elasticity are also presented for reference, and no clear analogy to compressible gases is obtained. (orig.)

  8. In vivo conditions to identify Prkci phosphorylation targets using the analog-sensitive kinase method in zebrafish.

    Directory of Open Access Journals (Sweden)

    Elena Cibrián Uhalte

    Full Text Available Protein kinase C iota is required for various cell biological processes including epithelial tissue polarity and organ morphogenesis. To gain mechanistic insight into different roles of this kinase, it is essential to identify specific substrate proteins in their cellular context. The analog-sensitive kinase method provides a powerful tool for the identification of kinase substrates under in vivo conditions. However, it has remained a major challenge to establish screens based on this method in multicellular model organisms. Here, we report the methodology for in vivo conditions using the analog-sensitive kinase method in a genetically-tractable vertebrate model organism, the zebrafish. With this approach, kinase substrates can uniquely be labeled in the developing zebrafish embryo using bulky ATPγS analogs which results in the thiophosphorylation of substrates. The labeling of kinase substrates with a thiophosphoester epitope differs from phosphoesters that are generated by all other kinases and allows for an enrichment of thiophosphopeptides by immunoaffinity purification. This study provides the foundation for using the analog-sensitive kinase method in the context of complex vertebrate development, physiology, or disease.

  9. Using Analogy to Improve Abstract Conditional Reasoning in Adolescents: Not as Easy as It Looks

    Science.gov (United States)

    Markovits, Henry; Doyon, Celine

    2011-01-01

    Abstract reasoning refers to the ability to reason logically with premises that do not allow reference to knowledge about the real world. This form of reasoning is complex and difficult, and at the same time, it is critical for understanding science and mathematics. Two studies examined the use of analogy as a method to bridge reasoning with…

  10. Spatio-Temporal Interpolation of Cloudy SST Fields Using Conditional Analog Data Assimilation

    Directory of Open Access Journals (Sweden)

    Ronan Fablet

    2018-02-01

    Full Text Available The ever increasing geophysical data streams pouring from earth observation satellite missions and numerical simulations along with the development of dedicated big data infrastructure advocate for truly exploiting the potential of these datasets, through novel data-driven strategies, to deliver enhanced satellite-derived gapfilled geophysical products from partial satellite observations. We here demonstrate the relevance of the analog data assimilation (AnDA for an application to the reconstruction of cloud-free level-4 gridded Sea Surface Temperature (SST. We propose novel AnDA models which exploit auxiliary variables such as sea surface currents and significantly reduce the computational complexity of AnDA. Numerical experiments benchmark the proposed models with respect to state-of-the-art interpolation techniques such as optimal interpolation and EOF-based schemes. We report relative improvement up to 40%/50% in terms of RMSE and also show a good parallelization performance, which supports the feasibility of an upscaling on a global scale.

  11. Cryogenics; Criogenia

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez R, C; Jimenez D, J; Cejudo A, J; Hernandez M, V [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    Cryogenics is one of these technologies which contributes to scientific research that supports to the industry in the following benefits: 1. Storage ability and a great quantity of dense gases with cryogenic liquid which is found at high pressure. 2. Production ability at low cost with high purity gases through distillation or condensation. 3. Ability to use low temperatures in the refrigerating materials or alteration of the physical properties. This technology is used for reprocessing of those short and long half life radioactive wastes which always have been required that to be separated with classical methods. In this text we report the radioactive wastes separation by more sophisticated methods but more quickly and reliable. (Author)

  12. Cryogenic regenerators

    International Nuclear Information System (INIS)

    Kush, P.; Joshi, S.C.; Thirumaleshwar, M.

    1986-01-01

    Importance of regenerators in cryogenic refrigerators is highlighted. Design aspects of regenerator are reviewed and the factors involved in the selection of regenerator material are enumerated. Various methods used to calculate the heat transfer coefficient and regenerator effectiveness are mentioned. Variation of effectiveness with various parameters is calculated by a computer programme using the ideal, Ackermann and Tipler formulae. Results are presented in graphical form. Listing of the computer programme is given in the Appendix. (author)

  13. Comparison of cryogenic (hydrogen) and TESPEL (polystyrene) pellet particle deposition in a magnetically confined plasma

    Science.gov (United States)

    McCarthy, K. J.; Tamura, N.; Combs, S. K.; Panadero, N.; Ascabíbar, E.; Estrada, T.; García, R.; Hernández Sánchez, J.; López Fraguas, A.; Navarro, M.; Pastor, I.; Soleto, A.; TJ-II Team

    2017-10-01

    A cryogenic pellet injector (PI) and tracer encapsulated solid pellet (TESPEL) injector system has been operated in combination on the stellarator TJ-II. This unique arrangement has been created by piggy-backing a TESPEL injector onto the backend of a pipe-gun-type PI. The combined injector provides a powerful new tool for comparing ablation and penetration of polystyrene TESPEL pellets and solid hydrogen pellets, as well as for contrasting subsequent pellet particle deposition and plasma perturbation under analogous plasma conditions. For instance, a significantly larger increase in plasma line-averaged electron density, and electron content, is observed after a TESPEL pellet injection compared with an equivalent cryogenic pellet injection. Moreover, for these injections from the low-magnetic-field side of the plasma cross-section, TESPEL pellets deposit electrons deeper into the plasma core than cryogenic pellets. Finally, the physics behind these observations and possible implications for pellet injection studies are discussed.

  14. Particles in a magnetic field and plasma analogies: doubly periodic boundary conditions

    International Nuclear Information System (INIS)

    Forrester, P J

    2006-01-01

    The N-particle free fermion state for quantum particles in the plane subject to a perpendicular magnetic field, and with doubly periodic boundary conditions, is written in a product form. The absolute value of this is used to formulate an exactly solvable one-component plasma model and further motivates the formulation of an exactly solvable two-species Coulomb gas. The large N expansion of the free energy of both these models exhibits the same O(1) term. On the basis of a relationship to the Gaussian free field, this term is predicted to be universal for conductive Coulomb systems in doubly periodic boundary conditions

  15. Cryogenic photodetectors

    Science.gov (United States)

    Chardin, G.

    2000-03-01

    Some of the most significant developments in cryogenic photodetectors are presented. In particular, the main characteristics of microbolometers involving Transition Edge- and NTD-sensors and offering resolutions of a few eV in the keV range, superconducting tunnel junction detectors with resolutions of the order of 10 eV or offering position sensitivity, and infrared bolometers with recent developments towards matrix detectors are discussed. Some of the recent achievements using large mass bolometers for gamma and neutron discriminating detectors, and future prospects of single photon detection in the far infrared using Single Electron Transistor devices are also presented.

  16. Cryogenic photodetectors

    CERN Document Server

    Chardin, G

    2000-01-01

    Some of the most significant developments in cryogenic photodetectors are presented. In particular, the main characteristics of microbolometers involving Transition Edge- and NTD-sensors and offering resolutions of a few eV in the keV range, superconducting tunnel junction detectors with resolutions of the order of 10 eV or offering position sensitivity, and infrared bolometers with recent developments towards matrix detectors are discussed. Some of the recent achievements using large mass bolometers for gamma and neutron discriminating detectors, and future prospects of single photon detection in the far infrared using Single Electron Transistor devices are also presented.

  17. Model photoautrophs isolated from a Proterozoic ocean analog - aerobic life under anoxic conditions

    Science.gov (United States)

    Hamilton, T. L.; de Beer, D.; Klatt, J.; Macalady, J.; Weber, M.; Lott, C.; Chennu, A.

    2016-12-01

    The 1-2 billion year delay before the final rise of oxygen at the end of the Proterozoic represents an important gap in our understanding of ancient biogeochemical cycling. Primary production fueled by sulfide-dependent anoxygenic photosynthesis, including the activity of metabolically versatile cyanobacteria, has been invoked as a mechanism for sustaining low atmospheric O2 throughout much of the Proterozoic. However, we understand very little about photoautotrophs that inhabit Proterozoic-like environments present on Earth today. Here we report on the isolation and characterization of a cyanobacterium and a green sulfur bacterium that are the dominant members of pinnacle mats in Little Salt Spring—a karst sinkhole in Florida with perennially low levels of dissolved oxygen and sulfide. The red pinnacle mats bloom in the anoxic basin of the sinkhole and receive light that is of very poor quality to support photosynthesis. Characterization of the isolates is consistent with observations of oxygenic and anoxygenic photosynthesis in situ—both organisms perform anoxygenic photosynthesis under conditions of very low light quality and quantity. Oxygenic photosynthesis by the cyanobacterium isolate is inhibited by the presence of sulfide and under optimal light conditions, rates of anoxygenic photosynthesis are nearly double that of oxygenic photosynthesis. The green sulfur bacterium is tolerant of oxygen and has a very low affinity for sulfide. In Little Salt Spring, oxygenic photosynthesis occurs for only four hours a day and the water column remains anoxic because of a continuous supply of sulfide. Isolation and characterization of these photoautotrophs combined with our high resolution microsensor data in situ highlight microbial biogeochemical cycling in this exceptional site where aerobic microorganisms persist in a largely anoxic ecosystem.

  18. Surface tension confined liquid cryogen cooler

    International Nuclear Information System (INIS)

    Castles, S.H.; Schein, M.E.

    1989-01-01

    A cryogenic cooler is described for use in craft such as launch, orbital and space vehicles subject to changes in orientation and conditions of vibration and weightlessness comprising: an insulated tank; a porous open celled sponge-like material disposed substantially throughout the contained volume of the insulated tank; a cryogenic fluid disposed within the sponge-like material; a cooling finger immersed in the cryogenic fluid, the finger extending from inside the insulated tank externally to an outside source such as an instrument detector for the purpose of transmitting heat from the outside source into the cryogenic fluid; means for filling the insulated tank with cryogenic fluid; and means for venting vaporized cryogenic fluid from the insulated tank

  19. Erythropoietin and a nonerythropoietic peptide analog promote aortic endothelial cell repair under hypoxic conditions: role of nitric oxide

    Directory of Open Access Journals (Sweden)

    Heikal L

    2016-08-01

    Full Text Available Lamia Heikal,1 Pietro Ghezzi,1 Manuela Mengozzi,1 Blanka Stelmaszczuk,2 Martin Feelisch,2 Gordon AA Ferns1 1Brighton and Sussex Medical School, Falmer, Brighton, 2Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital and Institute for Life Sciences, Southampton, UK Abstract: The cytoprotective effects of erythropoietin (EPO and an EPO-related nonerythropoietic analog, pyroglutamate helix B surface peptide (pHBSP, were investigated in an in vitro model of bovine aortic endothelial cell injury under normoxic (21% O2 and hypoxic (1% O2 conditions. The potential molecular mechanisms of these effects were also explored. Using a model of endothelial injury (the scratch assay, we found that, under hypoxic conditions, EPO and pHBSP enhanced scratch closure by promoting cell migration and proliferation, but did not show any effect under normoxic conditions. Furthermore, EPO protected bovine aortic endothelial cells from staurosporine-induced apoptosis under hypoxic conditions. The priming effect of hypoxia was associated with stabilization of hypoxia inducible factor-1α, EPO receptor upregulation, and decreased Ser-1177 phosphorylation of endothelial nitric oxide synthase (NOS; the effect of hypoxia on the latter was rescued by EPO. Hypoxia was associated with a reduction in nitric oxide (NO production as assessed by its oxidation products, nitrite and nitrate, consistent with the oxygen requirement for endogenous production of NO by endothelial NOS. However, while EPO did not affect NO formation in normoxia, it markedly increased NO production, in a manner sensitive to NOS inhibition, under hypoxic conditions. These data are consistent with the notion that the tissue-protective actions of EPO-related cytokines in pathophysiological settings associated with poor oxygenation are mediated by NO. These findings may be particularly relevant to atherogenesis and postangioplasty restenosis. Keywords

  20. LDR cryogenics

    Science.gov (United States)

    Nast, T.

    1988-01-01

    A brief summary from the 1985 Large Deployable Reflector (LDR) Asilomar 2 workshop of the requirements for LDR cryogenic cooling is presented. The heat rates are simply the sum of the individual heat rates from the instruments. Consideration of duty cycle will have a dramatic effect on cooling requirements. There are many possible combinations of cooling techniques for each of the three temperatures zones. It is clear that much further system study is needed to determine what type of cooling system is required (He-2, hybrid or mechanical) and what size and power is required. As the instruments, along with their duty cycles and heat rates, become better defined it will be possible to better determine the optimum cooling systems.

  1. Cryogenic detectors

    International Nuclear Information System (INIS)

    Zehnder, A.

    1987-01-01

    Presently the development of new large scale detector systems, used in very high energy physics experiments, is very active. In the low energy range, the introduction of charge coupled devices allows improved spacial and energy resolution. In the keV region, high resolution can only be achieved via the well established diffraction spectrometers with the well-known disadvantage of a small throughput. There exist no efficient detectors for non-ionizing radiation such as coherent nuclear scattering of weakly interacting particles. The development of high resolution solid state detectors in the keV-region with the possibility of nuclear recoil detection is therefore highly desired. Such detectors applied in astro and particle physics would thus allow one to obtain new information not achievable otherwise. Three types of cryogenic detectors exist: Calorimeters/Bolometers. This type is sensitive to the produced excess phonons and measures the deposited energy by detecting the heat pulses. Excess charge carriers should be used to produce phonons. Tunneling junctions. This type is sensitive to excess charge produced by the Cooper pair breakup. Excess phonons should be used to break up Cooper pairs. Superheated superconducting granules (SSG). An SSG detector consists of granules, the metastability of which is disturbed by radiation. The Meissner effect then causes a change in the field distribution of the applied external field, which can be detected. The present paper discusses the basic principle of calorimetric and tunneling junction detectors and some of their applications. 26 refs., 7 figs., 1 tab

  2. The ACTH4–9 analog ORG 2766 ‘normalizes’ the changes in motor activities of rats elicited by housing and test conditions

    NARCIS (Netherlands)

    Wolterink, G.; Ree, J.M. van

    1987-01-01

    Motor activities of rats were decreased by short-term (7 days) social isolation as well as by intense light test conditions. The ACTH4-9 analog ORG 2766, s.c. administered 50 min before testing, dose-dependently decreased the high motor activities of group-housed housed rats tested under low light

  3. Energy Efficient Cryogenics

    Science.gov (United States)

    Meneghelli, Barry J.; Notardonato, William; Fesmire, James E.

    2016-01-01

    The Cryogenics Test Laboratory, NASA Kennedy Space Center, works to provide practical solutions to low-temperature problems while focusing on long-term technology targets for the energy-efficient use of cryogenics on Earth and in space.

  4. Cryogenics a textbook

    CERN Document Server

    Thipse, S S

    2013-01-01

    A Textbook covers lucidly various cryogenic applications including cryogenic engines and space and electronic applications. Importance of cryogenic engines in space propulsion, complete thermodynamic analysis of cryogenic systems with special emphasis on cryogenic cycles, Dewar vessels used to store cryogenic fluids and their applications in various industries have also been discussed in detail. Explanation of Superconductivity and its applications with a description of various Cryocoolers used in industry has also been provided with extensive details. Further technical information on cryogens has been specified alongwith the vacuum technology which has been sufficiently described with examples. Science of Cryonics has been elaborated and all aspects of technology related to functioning of cryogenic plants and their construction including valves, pipes has been incorporated in this book.

  5. Cryogenic immersion microscope

    Science.gov (United States)

    Le Gros, Mark; Larabell, Carolyn A.

    2010-12-14

    A cryogenic immersion microscope whose objective lens is at least partially in contact with a liquid reservoir of a cryogenic liquid, in which reservoir a sample of interest is immersed is disclosed. When the cryogenic liquid has an index of refraction that reduces refraction at interfaces between the lens and the sample, overall resolution and image quality are improved. A combination of an immersion microscope and x-ray microscope, suitable for imaging at cryogenic temperatures is also disclosed.

  6. Encouraging conceptual change: the use of bridging analogies in the teaching of action reaction forces and the `at rest' condition in physics

    Science.gov (United States)

    Bryce, Tom; MacMillan, Kenneth

    2005-06-01

    The qualitative study described in this paper examined the effectiveness of bridging analogies intended to bring about conceptual change as part of a constructivist approach to teaching about action reaction forces in the ‘at rest’ condition in physics. Twenty-one 15-year-old students were involved in the investigation with subgroups previously exposed to different information regarding forces, weight and the accepted cause of the reaction force, in simple physical arrangements, including objects on tables. In-depth ‘think aloud’ interviews were used to track each student’s conceptual status as they worked with bridging analogies and transcript coding was carried out using open and axial coding (as in a grounded theory methodology). The findings showed that the bridging analogies were effective in engaging students with the idea of action reaction forces; students were adept in mapping each of the analogies to the target concept and using them to generate and refine their causal theories for the reaction force. There was evidence to suggest that, for some students, bridging analogies were more effective in bringing about conceptual change than didactic teaching. Their use extends beyond illustrative purposes and supports the development of meta-cognitive skills.

  7. Cryogen Safety Course 8876

    Energy Technology Data Exchange (ETDEWEB)

    Glass, George [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-13

    Cryogenics (from the Greek word κρvoζ, meaning frost or icy cold) is the study of the behavior of matter at very cold temperatures. The purpose of this course is to provide trainees with an introduction to cryogen use, the hazards and potential accidents related to cryogen systems, cryogen safety components, and the requirements that govern the design and use of cryogen systems at Los Alamos National Laboratory (LANL). The knowledge you gain will help you keep your workplace safe for yourself and your coworkers.

  8. Cryogenic heat transfer

    CERN Document Server

    Barron, Randall F

    2016-01-01

    Cryogenic Heat Transfer, Second Edition continues to address specific heat transfer problems that occur in the cryogenic temperature range where there are distinct differences from conventional heat transfer problems. This updated version examines the use of computer-aided design in cryogenic engineering and emphasizes commonly used computer programs to address modern cryogenic heat transfer problems. It introduces additional topics in cryogenic heat transfer that include latent heat expressions; lumped-capacity transient heat transfer; thermal stresses; Laplace transform solutions; oscillating flow heat transfer, and computer-aided heat exchanger design. It also includes new examples and homework problems throughout the book, and provides ample references for further study.

  9. The Radiation Tolerant Electronics for the LHC Cryogenic Controls: Basic Design and First Operational Experience

    CERN Document Server

    Casas-Cubillos, J; Rodríguez-Ruiz, M A

    2008-01-01

    The LHC optics is based in the extensive use of superconducting magnets covering 23 km inside the tunnel. The associated cryogenic system for keeping the magnets in nominal conditions is hence distributed all around the 27 km LHC tunnel and the cryogenic instrumentation submitted to the LHC radiation environment is composed of about 18’000 sensors and actuators. Radiation Tolerant (RadTol) electronics was designed and procured in order to keep the signals integrity against electromagnetic interference and to reduce cabling costs required in case of sending the analog signals into the 30 radiation protected areas. This paper presents the basic design, the qualification of the main RadTol components and the first operational results.

  10. Analog computing

    CERN Document Server

    Ulmann, Bernd

    2013-01-01

    This book is a comprehensive introduction to analog computing. As most textbooks about this powerful computing paradigm date back to the 1960s and 1970s, it fills a void and forges a bridge from the early days of analog computing to future applications. The idea of analog computing is not new. In fact, this computing paradigm is nearly forgotten, although it offers a path to both high-speed and low-power computing, which are in even more demand now than they were back in the heyday of electronic analog computers.

  11. Below-Ambient and Cryogenic Thermal Testing

    Science.gov (United States)

    Fesmire, James E.

    2016-01-01

    Thermal insulation systems operating in below-ambient temperature conditions are inherently susceptible to moisture intrusion and vapor drive toward the cold side. The subsequent effects may include condensation, icing, cracking, corrosion, and other problems. Methods and apparatus for real-world thermal performance testing of below-ambient systems have been developed based on cryogenic boiloff calorimetry. New ASTM International standards on cryogenic testing and their extension to future standards for below-ambient testing of pipe insulation are reviewed.

  12. Fundamental of cryogenics (for superconducting RF technology)

    CERN Document Server

    Pierini, Paolo

    2013-01-01

    This review briefly illustrates a few fundamental concepts of cryogenic engineering, the technological practice that allows reaching and maintaining the low-temperature operating conditions of the superconducting devices needed in particle accelerators. To limit the scope of the task, and not to duplicate coverage of cryogenic engineering concepts particularly relevant to superconducting magnets that can be found in previous CAS editions, the overview presented in this course focuses on superconducting radio-frequency cavities.

  13. Introduction to cryogenic engineering

    CERN Multimedia

    CERN. Geneva; Vandoni, Giovanna; Niinikoski, Tapio O

    2005-01-01

    Cryogenic engineering is one of the key technologies at CERN. It is widely used in research and has many applications in industry and last but not least in medicine. In research cryogenic engineering and its applications are omnipresent from the smallest laboratories to fusion reactors, hughe detectors and accelerators. With the termination of the LHC, CERN will in fact become the world's largest cryogenic installation. This series of talks intends to introduce the non-cryogenist to the basic principles and challenges of cryogenic engineering and its applications. The course will also provide a basis for practical application as well as for further learning.

  14. Cryogenics for LDR

    Science.gov (United States)

    Kittel, Peter

    1988-01-01

    Three cryogenic questions of importance to Large Deployable Reflector (LDR) are discussed: the primary cooling requirement, the secondary cooling requirement, and the instrument changeout requirement.

  15. Optical analogy. Synthesis report

    International Nuclear Information System (INIS)

    1965-01-01

    The authors report the study of conditions under which light attenuation (reflection, diffusion, absorption) and the attenuation of some radiations (notably thermal neutrons) can be described with analogical calculations. The analogy between light physical properties and neutron properties is not searched for, but the analogy between their attenuation characteristics. After having discussed this possible analogy, they propose a mathematical formulation of neutron and optical phenomena which could theoretically justify the optical analogy. The second part reports a more practical study of optics problems such as the study of simple optics materials and illumination measurements, or more precisely the study of angular distributions of optical reflections, a determination of such angular distributions, and an experimental determination of the albedo

  16. MOSFET's for Cryogenic Amplifiers

    Science.gov (United States)

    Dehaye, R.; Ventrice, C. A.

    1987-01-01

    Study seeks ways to build transistors that function effectively at liquid-helium temperatures. Report discusses physics of metaloxide/semiconductor field-effect transistors (MOSFET's) and performances of these devices at cryogenic temperatures. MOSFET's useful in highly sensitive cryogenic preamplifiers for infrared astronomy.

  17. MFTF magnet cryogenics

    International Nuclear Information System (INIS)

    VanSant, J.H.

    1981-07-01

    The prime requirement of the cryogenics of the magnets is to assure a superconducting state for the magnet coils, a large task considering their enormous size. The following presentation addresses the principal topics that have been considered in this cryogenic design

  18. The Nuclear Cryogenic Propulsion Stage

    Science.gov (United States)

    Houts, Michael G.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Broadway, Jeramie W.; Gerrish, Harold P.; Doughty, Glen; Belvin, Anthony; Borowski, Stanley K.; Scott, John

    2014-01-01

    The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP). Nuclear propulsion can be affordable and viable compared to other propulsion systems and must overcome a biased public fear due to hyper-environmentalism and a false perception of radiation and explosion risk.

  19. An analogy for evaporative heat transfer with wavy/stratified air-water flow in vertical counter-current flow conditions

    International Nuclear Information System (INIS)

    Kweon, H.; Park, K. C.

    2001-01-01

    An analogy for evaporative heat transfer with mass transfer was derived. From von-Karman analogy which has been applied between heat and momentum transfer in single phase turbulent flow, a modified Karman analogy was suggested at present paper. Nusselt number from this analogy showed good agreement with experimental results. Such a result shows that the analogy for a complex heat transfer mode between heat transfer and momentum transfer accompanying evaporation or condensation on the interface can be established

  20. Integrated cryogenic sensors

    International Nuclear Information System (INIS)

    Juanarena, D.B.; Rao, M.G.

    1991-01-01

    Integrated cryogenic pressure-temperature, level-temperature, and flow-temperature sensors have several advantages over the conventional single parameter sensors. Such integrated sensors were not available until recently. Pressure Systems, Inc. (PSI) of Hampton, Virginia, has introduced precalibrated precision cryogenic pressure sensors at the Los Angeles Cryogenic Engineering Conference in 1989. Recently, PSI has successfully completed the development of integrated pressure-temperature and level-temperature sensors for use in the temperature range 1.5-375K. In this paper, performance characteristics of these integrated sensors are presented. Further, the effects of irradiation and magnetic fields on these integrated sensors are also reviewed

  1. Cryogenics will cool LHC

    International Nuclear Information System (INIS)

    Anon.

    2001-01-01

    Results of the investigation into the cryogenic regulating line (QRL) performed by the LHC laboratory are presented. It is projected that eight cryogenic units located in five places around the LHC ring will provide superconducting magnets by liquid helium through eight cryogenic regulating lines of 3.2 km each. All QRL zones remain to be independent. CERN uses three test units with the aim of the certification of chosen constructions and verification of their thermal and mechanical efficiency before starting full-scale production [ru

  2. Fundamentals of cryogenic engineering

    CERN Document Server

    Mukhopadhyay, Mamata

    2014-01-01

    The author, with her vast and varied experience in teaching and allied fields, clearly enunciates the behaviour and various properties of common cryogenic fluids, methods of liquefaction, and separation and applications of cryogens with thermodynamic analysis for process selection. This profusely illustrated study with clear-cut diagrams and process charts, should serve not only as a textbook for students but also as an excellent reference for researchers and practising engineers on design of cryogenic refrigeration, and liquefaction and separation process plants for various applications.

  3. Polymers at cryogenic temperatures

    CERN Document Server

    Fu, Shao-Yun

    2013-01-01

    Kalia and Fu's novel monograph covers cryogenic treatment, properties and applications of cryo-treated polymer materials. Written by numerous international experts, the twelve chapters in this book offer the reader a comprehensive picture of the latest findings and developments, as well as an outlook on the field. Cryogenic technology has seen remarkable progress in the past few years and especially cryogenic properties of polymers are attracting attention through new breakthroughs in space, superconducting, magnetic and electronic techniques. This book is a valuable resource for researchers, educators, engineers and graduate students in the field and at technical institutions.

  4. FRIB Cryogenic Plant Status

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Kelly D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Ganni, Venkatarao [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Knudsen, Peter N. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Casagranda, Fabio [Michigan State Univ., East Lansing, MI (United States)

    2015-12-01

    After practical changes were approved to the initial conceptual design of the cryogenic system for MSU FRIB and an agreement was made with JLab in 2012 to lead the design effort of the cryogenic plant, many activities are in place leading toward a cool-down of the linacs prior to 2018. This is mostly due to using similar equipment used at CHLII for the 12 GeV upgrade at JLab and an aggressive schedule maintained by the MSU Conventional Facilities department. Reported here is an updated status of the cryogenic plant, including the equipment procurement status, plant layout, facility equipment and project schedule.

  5. Communication: Orientational self-ordering of spin-labeled cholesterol analogs in lipid bilayers in diluted conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kardash, Maria E.; Dzuba, Sergei A., E-mail: dzuba@kinetics.nsc.ru [Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia, and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2014-12-07

    Lipid-cholesterol interactions are responsible for different properties of biological membranes including those determining formation in the membrane of spatial inhomogeneities (lipid rafts). To get new information on these interactions, electron spin echo (ESE) spectroscopy, which is a pulsed version of electron paramagnetic resonance (EPR), was applied to study 3β-doxyl-5α-cholestane (DCh), a spin-labeled analog of cholesterol, in phospholipid bilayer consisted of equimolecular mixture of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphocholine. DCh concentration in the bilayer was between 0.1 mol.% and 4 mol.%. For comparison, a reference system containing a spin-labeled 5-doxyl-stearic acid (5-DSA) instead of DCh was studied as well. The effects of “instantaneous diffusion” in ESE decay and in echo-detected (ED) EPR spectra were explored for both systems. The reference system showed good agreement with the theoretical prediction for the model of spin labels of randomly distributed orientations, but the DCh system demonstrated remarkably smaller effects. The results were explained by assuming that neighboring DCh molecules are oriented in a correlative way. However, this correlation does not imply the formation of clusters of cholesterol molecules, because conventional continuous wave EPR spectra did not show the typical broadening due to aggregation of spin labels and the observed ESE decay was not faster than in the reference system. So the obtained data evidence that cholesterol molecules at low concentrations in biological membranes can interact via large distances of several nanometers which results in their orientational self-ordering.

  6. Cryogenics theory, processes and applications

    CERN Document Server

    Hayes, Allyson E

    2011-01-01

    Cryogenics is the study of the production of very low temperature (below -150 -C, -238 -F or 123 K) and the behaviour of materials at those temperatures. This book presents current research from across the globe in the study of cryogenics, including the effect of cryogenic treatment on microstructure and mechanical properties of light weight alloys; the application of Fiber Bragg grating sensors at cryogenic temperatures; cryogenic grinding; liquid oxygen magnetohydrodynamics; and, genetic engineering techniques used to improve tolerance to cryopreservation.

  7. Analog earthquakes

    International Nuclear Information System (INIS)

    Hofmann, R.B.

    1995-01-01

    Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository

  8. Cryogenics for LHC experiments

    CERN Multimedia

    2001-01-01

    Cryogenic systems will be used by LHC experiments to maximize their performance. Institutes around the world are collaborating with CERN in the construction of these very low temperature systems. The cryogenic test facility in hall 180 for ATLAS magnets. High Energy Physics experiments have frequently adopted cryogenic versions of their apparatus to achieve optimal performance, and those for the LHC will be no exception. The two largest experiments for CERN's new flagship accelerator, ATLAS and CMS, will both use large superconducting magnets operated at 4.5 Kelvin - almost 270 degrees below the freezing point of water. ATLAS also includes calorimeters filled with liquid argon at 87 Kelvin. For the magnets, the choice of a cryogenic version was dictated by a combination economy and transparency to emerging particles. For the calorimeters, liquid argon was selected as the fluid best suited to the experiment's physics requirements. High Energy Physics experiments are the result of worldwide collaborations and...

  9. Advances in Cryogenic Principles

    Science.gov (United States)

    Barron, R. F.

    During the past 50 years, the use of digital computers has significantly influenced the design and analysis of cryogenic systems. At the time when the first Cryogenic Engineering Conference was held, thermodynamic data were presented in graphical or tabular form (the "steam table" format), whereas thermodynamic data for cryogenic system design is computer generated today. The thermal analysis of cryogenic systems in the 1950s involved analytical solutions, graphical solutions, and relatively simple finite-difference approaches. These approaches have been supplanted by finite-element numerical programs which readily solve complicated thermal problems that could not be solved easily using the methods of the 1950s. In distillation column design, the use of the McCabe-Thiele graphical method for determination of the number of theoretical plates has been replaced by numerical methods that allow consideration of several different components in the feed and product streams.

  10. The Cryogenic Supervision System in NSRRC

    CERN Document Server

    Li, Hsing-Chieh; Chiou, Wen-Song; Hsiao, Feng-Zone; Tsai, Zong-Da

    2005-01-01

    The helium cryogenic system in NSRRC is a fully automatic PLC system using the Siemens SIMATIC 300 controller. Modularization in both hardware and software makes it easy in the program reading, the system modification and the problem debug. Based on the Laview program we had developed a supervision system taking advantage of the Internet technology to get system's real-time information in any place. The functions of this supervision system include the real-time data accessing with more than 300 digital/analog signals, the data restore, the history trend display, and the human machine interface. The data is accessed via a Profibus line connecting the PLC system and the supervision system with a maximum baud rate 1.5 Mbit/s. Due to this supervision system, it is easy to master the status of the cryogenic system within a short time and diagnose the problem.

  11. Commissioning the cryogenic system of the first LHC sector

    International Nuclear Information System (INIS)

    Millet, F.; Claudet, S.; Ferlin, G.; Perin, A.; Riddone, G.; Serio, L.; Soubiran, M.; Tavian, L.; CERN; Ronayette, L.; GHMFL, Grenoble; Rabehl, R.; Fermilab

    2007-01-01

    The LHC machine, composed of eight sectors with superconducting magnets and accelerating cavities, requires a complex cryogenic system providing high cooling capacities (18 kW equivalent at 4.5 K and 2.4 W at 1.8 K per sector produced in large cold boxes and distributed via 3.3-km cryogenic transfer lines). After individual reception tests of the cryogenic subsystems (cryogen storages, refrigerators, cryogenic transfer lines and distribution boxes) performed since 2000, the commissioning of the cryogenic system of the first LHC sector has been under way since November 2006. After a brief introduction to the LHC cryogenic system and its specificities, the commissioning is reported detailing the preparation phase (pressure and leak tests, circuit conditioning and flushing), the cool-down sequences including the handling of cryogenic fluids, the magnet powering phase and finally the warm-up. Preliminary conclusions on the commissioning of the first LHC sector will be drawn with the review of the critical points already solved or still pending. The last part of the paper reports on the first operational experience of the LHC cryogenic system in the perspective of the commissioning of the remaining LHC sectors and the beam injection test

  12. Use of natural and archaeological analogs to validate long - term behaviour of HLW glass in geological disposal conditions

    International Nuclear Information System (INIS)

    Gin, S.; Verney-Carron, A.; Libourel, G.

    2008-01-01

    Some old basaltic and Roman glasses have been studied in order to validate the predictive models developed for assessing the long-term behaviour of nuclear glass in geological repository conditions. Leaching behaviour of basaltic glass altered in both laboratory and natural environment conditions allows to validate the key mechanisms that control glass dissolution kinetics and the order of magnitude of glass packages lifetime In a stable clayey formation (French reference concept for a geological disposal of high level waste). The study of Roman glass blocks (with the same geometry as nuclear glass package) altered during 1800 years in a marine environment gives new insight on the basic mechanisms involved in confined media (fractures and small cracks). Results show the importance of the coupling between transport of reactive species and chemical reactions. This study, still in progress, would allow to validate the modelling of such a complex system. (author)

  13. The dissolution rate of UO2 in the alkaline regime under oxidizing conditions using a simplified ground water analog

    International Nuclear Information System (INIS)

    Leider, H.R.; Nguyen, S.N.; Weed, H.C.; Steward, S.A.

    1992-01-01

    The major factor controlling the long term release of radionuclides from spent fuel in a geologic repository is the leaching/dissolution by groundwater of the UO 2 matrix, since more than 90% of the radionuclide waste is contained in the fuel matrix. The objective of this investigation is to provide experimental dissolution rates for UO 2 samples which can be used to develop a mechanistic release model (or models) for UO 2+x (x≥0) under repository conditions. Several types of data will be obtained from this study: (1) the dissolution rates of UO 2 as a function of pI-L temperature, carbonate and oxygen fugacity; (2) the comparison of the steady state dissolution rates of ''not-reduced'' versus ''reduced'' UO 2 samples and of single crystal versus polycrystalline UO 2 under identical experimental conditions; (3) the pre- and post-test surface analyses of the samples to provide information on the surface phases that may be formed under experimental conditions

  14. Simple Spreadsheet Thermal Models for Cryogenic Applications

    Science.gov (United States)

    Nash, Alfred

    1995-01-01

    Self consistent circuit analog thermal models that can be run in commercial spreadsheet programs on personal computers have been created to calculate the cooldown and steady state performance of cryogen cooled Dewars. The models include temperature dependent conduction and radiation effects. The outputs of the models provide temperature distribution and Dewar performance information. these models have been used to analyze the SIRTF Telescope Test Facility (STTF). The facility has been brought on line for its first user, the Infrared Telescope Technology Testbed (ITTT), for the Space Infrared Telescope Facility (SIRTF) at JPL. The model algorithm as well as a comparison between the models' predictions and actual performance of this facility will be presented.

  15. TPC magnet cryogenic system

    International Nuclear Information System (INIS)

    Green, M.A.; Burns, W.A.; Taylor, J.D.; Van Slyke, H.W.

    1980-03-01

    The Time Projection Chamber (TPC) magnet at LBL and its compensation solenoids are adiabatically stable superconducting solenoid magnets. The cryogenic system developed for the TPC magnet is discussed. This system uses forced two-phase tubular cooling with the two cryogens in the system. The liquid helium and liquid nitrogen are delivered through the cooled load by forced tubular flow. The only reservoirs of liquid cryogen exist in the control dewar (for liquid helium) and the conditioner dewar (for liquid nitrogen). The operation o these systems during virtually all phases of system operation are described. Photographs and diagrams of various system components are shown, and cryogenic system data are presented in the following sections: (1) heat leaks into the TPC coil package and the compensation solenoids; (2) heat leaks to various components of the TPC magnet cryogenics system besides the magnets and control dewar; (3) the control dewar and its relationship to the rest of the system; (4) the conditioner system and its role in cooling down the TPC magnet; (5) gas-cooled electrical leads and charging losses; and (6) a summation of the liquid helium and liquid nitrogen requirements for the TPC superconducting magnet system

  16. Cryogenic Fluid Management Facility

    Science.gov (United States)

    Eberhardt, R. N.; Bailey, W. J.

    1985-01-01

    The Cryogenic Fluid Management Facility is a reusable test bed which is designed to be carried within the Shuttle cargo bay to investigate the systems and technologies associated with the efficient management of cryogens in space. Cryogenic fluid management consists of the systems and technologies for: (1) liquid storage and supply, including capillary acquisition/expulsion systems which provide single-phase liquid to the user system, (2) both passive and active thermal control systems, and (3) fluid transfer/resupply systems, including transfer lines and receiver tanks. The facility contains a storage and supply tank, a transfer line and a receiver tank, configured to provide low-g verification of fluid and thermal models of cryogenic storage and transfer processes. The facility will provide design data and criteria for future subcritical cryogenic storage and transfer system applications, such as Space Station life support, attitude control, power and fuel depot supply, resupply tankers, external tank (ET) propellant scavenging, and ground-based and space-based orbit transfer vehicles (OTV).

  17. Cryogen therapy of skin cancer

    International Nuclear Information System (INIS)

    Zikiryakhodjaev, D.Z.; Sanginov, D.R.

    2001-01-01

    In this chapter authors studied the cure of skin cancer in particular cryogen therapy of skin cancer. They noted that cryogen therapy of skin cancer carried new possibilities and improved results of neoplasms treatment

  18. Validation and Performance of the LHC Cryogenic System through Commissioning of the First Sector

    CERN Document Server

    Serio, L; Casas-Cubillos, J; Chakravarty, A; Claudet, S; Gicquel, F; Gomes, P; Kumar, M; Kush, PK; Millet, F; Perin, A; Rabehl, R; Singh, MR; Soubiran, M; Tavian, L

    2008-01-01

    The cryogenic system [1] for the Large Hadron Collider accelerator is presently in its final phase of commissioning at nominal operating conditions. The refrigeration capacity for the LHC is produced using eight large cryogenic plants and eight 1.8 K refrigeration units installed on five cryogenic islands. Machine cryogenic equipment is installed in a 26.7-km circumference ring deep underground tunnel and are maintained at their nominal operating conditions via a distribution system consisting of transfer lines, cold interconnection boxes at each cryogenic island and a cryogenic distribution line. The functional analysis of the whole system during all operating conditions was established and validated during the first sector commissioning in order to maximize the system availability. Analysis, operating modes, main failure scenarios, results and performance of the cryogenic system are presented.

  19. Long-term cryogenic space storage system

    Science.gov (United States)

    Hopkins, R. A.; Chronic, W. L.

    1973-01-01

    Discussion of the design, fabrication and testing of a 225-cu ft spherical cryogenic storage system for long-term subcritical applications under zero-g conditions in storing subcritical cryogens for space vehicle propulsion systems. The insulation system design, the analytical methods used, and the correlation between the performance test results and analytical predictions are described. The best available multilayer insulation materials and state-of-the-art thermal protection concepts were applied in the design, providing a boiloff rate of 0.152 lb/hr, or 0.032% per day, and an overall heat flux of 0.066 Btu/sq ft hr based on a 200 sq ft surface area. A six to eighteen month cryogenic storage is provided by this system for space applications.

  20. Cryogenic Thermometer Calibration Facility at CERN

    CERN Document Server

    Balle, C; Thermeau, J P

    1998-01-01

    A cryogenic thermometer calibration facility has been designed and is being commissioned in preparation for the very stringent requirements on the temperature control of the LHC superconducting magnets. The temperature is traceable in the 1.5 to 30 K range to standards maintained in a national metrological laboratory by using a set of Rhodium-Iron temperature sensors of metrological quality. The calibration facility is designed for calibrating simultaneously 60 industrial cryogenic thermometers in the 1.5 K to 300 K temperature range, a thermometer being a device that includes both a temperature sensor and the wires heat-intercept. The thermometers can be calibrated in good and degraded vacuum or immersed in the surrounding fluid and at different Joule self-heating conditions that match those imposed by signal conditioners used in large cryogenic machinery. The calibration facility can be operated in an automatic mode and all the control and safety routines are handled by a Programmable Logic Controller (PLC)...

  1. The Paradox of Analogy

    Directory of Open Access Journals (Sweden)

    David Botting

    2012-03-01

    Full Text Available I will show that there is a type of analogical reasoning that instantiates a pattern of reasoning in confirmation theory that is considered at best paradoxical and at worst fatal to the entire syntactical approach to confirmation and explanation. However, I hope to elaborate conditions under which this is a sound (although not necessarily strong method of reasoning.

  2. Cryogenic process simulation

    International Nuclear Information System (INIS)

    Panek, J.; Johnson, S.

    1994-01-01

    Combining accurate fluid property databases with a commercial equation-solving software package running on a desktop computer allows simulation of cryogenic processes without extensive computer programming. Computer simulation can be a powerful tool for process development or optimization. Most engineering simulations to date have required extensive programming skills in languages such as Fortran, Pascal, etc. Authors of simulation code have also usually been responsible for choosing and writing the particular solution algorithm. This paper describes a method of simulating cryogenic processes with a commercial software package on a desktop personal computer that does not require these traditional programming tasks. Applications include modeling of cryogenic refrigerators, heat exchangers, vapor-cooled power leads, vapor pressure thermometers, and various other engineering problems

  3. CEBAF cryogenic system

    International Nuclear Information System (INIS)

    1995-01-01

    The CEBAF cryogenic system consists of 3 refrigeration systems: Cryogenic Test Facility (CTF), Central Helium Liquefier (CHL), and End Station Refrigerator (ESR). CHL is the main cryogenic system for CEBAF, consisting of a 4.8 kW, 2.0 K refrigerator and transfer line system to supply 2.0 K and 12 kW of 50 K shield refrigeration for the Linac cavity cryostats and 10 g/s of liquid for the end stations. This paper describes the 9-year effort to commission these systems, concentrating on CHL with the cold compressors. The cold compressors are a cold vacuum pump with an inlet temperature of 3 K which use magnetic bearings, thereby eliminating the possibility of air leaks into the subatmospheric He

  4. Cryogenic support member

    International Nuclear Information System (INIS)

    Niemann, R.C.; Gonczy, J.D.; Nicol, T.H.

    1987-01-01

    A cryogenic support member is described for restraining a cryogenic system comprising; a rod having a depression at a first end. The rod is made of non-metallic material. The non-metallic material has an effectively low thermal conductivity; a metallic plug; and a metallic sleeve. The plug and the sleeve are shrink-fitted to the depression in the rod and assembled thereto such that the plug is disposed inside the depression of the rod. The sleeve is disposed over the depression in the rod and the rod is clamped therebetween. The shrink-fit clamping the rod is generated between the metallic plug and the metallic sleeve

  5. Prediction of heat transfer coefficients for forced convective boiling of N2-hydrocarbon mixtures at cryogenic conditions using artificial neural networks

    Science.gov (United States)

    Barroso-Maldonado, J. M.; Belman-Flores, J. M.; Ledesma, S.; Aceves, S. M.

    2018-06-01

    A key problem faced in the design of heat exchangers, especially for cryogenic applications, is the determination of convective heat transfer coefficients in two-phase flow such as condensation and boiling of non-azeotropic refrigerant mixtures. This paper proposes and evaluates three models for estimating the convective coefficient during boiling. These models are developed using computational intelligence techniques. The performance of the proposed models is evaluated using the mean relative error (mre), and compared to two existing models: the modified Granryd's correlation and the Silver-Bell-Ghaly method. The three proposed models are distinguished by their architecture. The first is based on directly measured parameters (DMP-ANN), the second is based on equivalent Reynolds and Prandtl numbers (eq-ANN), and the third on effective Reynolds and Prandtl numbers (eff-ANN). The results demonstrate that the proposed artificial neural network (ANN)-based approaches greatly outperform available methodologies. While Granryd's correlation predicts experimental data within a mean relative error mre = 44% and the S-B-G method produces mre = 42%, DMP-ANN has mre = 7.4% and eff-ANN has mre = 3.9%. Considering that eff-ANN has the lowest mean relative error (one tenth of previously available methodologies) and the broadest range of applicability, it is recommended for future calculations. Implementation is straightforward within a variety of platforms and the matrices with the ANN weights are given in the appendix for efficient programming.

  6. Cryogenics system: strategy to achieve nominal performance and reliable operation

    International Nuclear Information System (INIS)

    Bremer, J.; Brodzinski, K.; Casas, J.; Claudet, S.; Delikaris, D.; Delruelle, N.; Ferlin, G.; Fluder, C.; Perin, A.; Perinic, G.; Pezzetti, M.; Pirotte, O.; Tavian, L.; Wagner, U.

    2012-01-01

    During the LHC operation in 2010 and 2011, the cryogenic system has achieved an availability level fulfilling the overall requirement. To reach this level, the cryogenic system has profited like many other beam-dependent systems from the reduced beam parameters. Therefore, impacts of some failures occurred during the LHC operation were mitigated by using the over-capacity margin, the existing built-in redundancy in between adjacent sector cryogenic plants and the 'cannibalization' of spares on two idle cryogenic plants. These two first years of operation were also crucial to identify the weaknesses of the present cryogenic maintenance plan and new issues like SEUs. After the LS1, nominal beam parameters are expected and the mitigated measures will be less effective or not applicable at all. Consequently, a consolidation plan to improve the MTBF and the MTTR of the LHC cryogenic system is under definition. Concerning shutdown periods, the present cryogenic sectorization imposes some restrictions in the type of interventions (e.g. cryo-magnet removal) which can be done without affecting the operating conditions of the adjacent sector. This creates additional constrains and possible extra down-time in the schedule of the shutdowns including the hardware commissioning. This presentation focuses on the consolidation plan foreseen during the LS1 to improve the performance of the LHC cryogenic system in terms of availability and sectorization. (authors)

  7. Effect of cryogenic treatment on distribution of residual stress in case carburized En 353 steel

    International Nuclear Information System (INIS)

    Bensely, A.; Venkatesh, S.; Mohan Lal, D.; Nagarajan, G.; Rajadurai, A.; Junik, Krzysztof

    2008-01-01

    The effect of cryogenic treatment on the distribution of residual stress in the case carburized steel (En 353) was studied using X-ray diffraction technique. Two types of cryogenic treatment: shallow cryogenic treatment (193 K) and deep cryogenic treatment (77 K) were adopted, as a supplement to conventional heat treatment. The amount of retained austenite in conventionally heat-treated, shallow cryogenically treated and deep cryogenically treated samples was found to be 28%, 22% and 14%, respectively. The conventionally heat-treated, shallow cryogenically treated and deep cryogenically treated samples in untempered condition had a surface residual stress of -125 MPa, -115 MPa and -235 MPa, respectively. After tempering the conventionally heat-treated, shallow cryogenically treated and deep cryogenically treated samples had a surface residual stress of -150 MPa, -80 MPa and -80 MPa, respectively. A comparative study of the three treatments revealed that there was an increase in the compressive residual stress in steel that was subjected to cryogenic treatment prior to tempering. The experimental investigation revealed that deep cryogenically treated steel when subjected to tempering has undergone a reduction in compressive residual stress. Such stress relieving behaviour was mainly due to the increased precipitation of fine carbides in specimens subjected to DCT with tempering

  8. Cryogenic vacuum pump design

    International Nuclear Information System (INIS)

    Bartlett, A.J.; Lessard, P.A.

    1984-01-01

    This paper is a review of the problems and tradeoffs involved in cryogenic vacuum pump analysis, design and manufacture. Particular attention is paid to the several issues unique to cryopumps, e.g., radiation loading, adsorption of noncondensible gases, and regeneration. A general algorithm for cryopump design is also proposed. 12 references

  9. Cryogenic current leads

    Energy Technology Data Exchange (ETDEWEB)

    Zizek, F.

    1982-01-01

    Theoretical, technical and design questions are examined of cryogenic current leads for SP of magnetic systems. Simplified mathematical models are presented for the current leads. To illustrate modeling, the calculation is made of the real current leads for 500 A and three variants of current leads for 1500 A for the enterprise ''Shkoda.''

  10. Structural transformations of 3-fluoro and 3-fluoro-4-methoxy benzaldehydes under cryogenic conditions: A computational and low temperature infrared spectroscopy investigation

    Science.gov (United States)

    Ogruc Ildiz, G.; Konarska, J.; Fausto, R.

    2018-05-01

    Structural transformations of 3-fluorobenzaldehyde (C7H5FO; 3FBA) and 3-fluoro-4-methoxybenzaldehyde (C8H7FO2; 3F4MBA), taking place in different solid phase environments and at low temperature, were investigated by infrared spectroscopy, complemented by quantum chemistry calculations undertaken at the DFT(B3LYP)/6-311++G(d,p) level of approximation. The studied compounds were isolated from gas phase into cryogenic inert matrices (Ar, Xe), allowing to characterize their equilibrium conformational composition in gas-phase at room temperature. In both cases, two conformers differing by the orientation of the aldehyde moiety (with the carbonyl aldehyde bond cis or trans in relation to the aromatic ring fluorine substituent) were found to coexist, with the cis conformer being slightly more populated than the trans form. In situ narrowband UV irradiation of the as-deposited matrices led either to preferential isomerization of the cis conformer into the trans form or decarbonylation of both conformers, depending on the used excitation wavelength. Deposition of the vapours of 3F4MBA only, onto the cold (15 K) substrate, produced an amorphous solid containing also both the cis and trans conformers of the compound. Subsequent heating of the amorphous phase up to 268 K led to crystallization of the compound, which is accompanied by conformational selection, the cis form being the single species present in the crystal. The experimentally observed transformations of the studied compounds, together with the structural and vibrational results obtained from the performed quantum chemical calculations, allowed a detailed structural and vibrational characterization of the individual conformers.

  11. Negative thermal expansion of lithium aluminosilicate ceramics at cryogenic temperatures

    International Nuclear Information System (INIS)

    Garcia-Moreno, Olga; Fernandez, Adolfo; Khainakov, Sergei; Torrecillas, Ramon

    2010-01-01

    Five lithium aluminosilicate compositions of the LAS system have been synthesized and sintered. The coefficient of thermal expansion of the sintered samples has been studied down to cryogenic conditions. The data presented here under cryogenic conditions will be of value in the future design of new composite materials with very low thermal expansion values. The variation in thermal expansion properties with composition and sintering temperature was studied and is discussed in relation to composition and crystal structure.

  12. A VME based cryogenic data acquisition and control system (CRYO-DACS)

    International Nuclear Information System (INIS)

    Antony, Joby; Rajkumar; Datta, T.S.

    2005-01-01

    This report describes a newly developed VME based data acquisition and control system named CRYO-DACS for acquiring and controlling various analog and digital cryogenic parameters from equipment's like beam-line cryostats, Helium compressors, liquefier, cryogenic distribution line etc. A new central control room has been set-up for the remote controls and monitoring. The system monitors various analog parameters like temperature, pressure, vacuum and cryogenic fluid levels inside the cryostats and performs closed loop controls of cryogen valves. The hardware architecture of CRYO-DACS is multi-crate distributed VME, all linked by workstation clients in 100 Mb/s LAN for distributed logging, historical trending, analysis, alarm management and control GUIs. (author)

  13. Selecting Populations for Non-Analogous Climate Conditions Using Universal Response Functions: The Case of Douglas-Fir in Central Europe.

    Science.gov (United States)

    Chakraborty, Debojyoti; Wang, Tongli; Andre, Konrad; Konnert, Monika; Lexer, Manfred J; Matulla, Christoph; Schueler, Silvio

    2015-01-01

    Identifying populations within tree species potentially adapted to future climatic conditions is an important requirement for reforestation and assisted migration programmes. Such populations can be identified either by empirical response functions based on correlations of quantitative traits with climate variables or by climate envelope models that compare the climate of seed sources and potential growing areas. In the present study, we analyzed the intraspecific variation in climate growth response of Douglas-fir planted within the non-analogous climate conditions of Central and continental Europe. With data from 50 common garden trials, we developed Universal Response Functions (URF) for tree height and mean basal area and compared the growth performance of the selected best performing populations with that of populations identified through a climate envelope approach. Climate variables of the trial location were found to be stronger predictors of growth performance than climate variables of the population origin. Although the precipitation regime of the population sources varied strongly none of the precipitation related climate variables of population origin was found to be significant within the models. Overall, the URFs explained more than 88% of variation in growth performance. Populations identified by the URF models originate from western Cascades and coastal areas of Washington and Oregon and show significantly higher growth performance than populations identified by the climate envelope approach under both current and climate change scenarios. The URFs predict decreasing growth performance at low and middle elevations of the case study area, but increasing growth performance on high elevation sites. Our analysis suggests that population recommendations based on empirical approaches should be preferred and population selections by climate envelope models without considering climatic constrains of growth performance should be carefully appraised before

  14. Selecting Populations for Non-Analogous Climate Conditions Using Universal Response Functions: The Case of Douglas-Fir in Central Europe

    Science.gov (United States)

    Chakraborty, Debojyoti; Wang, Tongli; Andre, Konrad; Konnert, Monika; Lexer, Manfred J.; Matulla, Christoph; Schueler, Silvio

    2015-01-01

    Identifying populations within tree species potentially adapted to future climatic conditions is an important requirement for reforestation and assisted migration programmes. Such populations can be identified either by empirical response functions based on correlations of quantitative traits with climate variables or by climate envelope models that compare the climate of seed sources and potential growing areas. In the present study, we analyzed the intraspecific variation in climate growth response of Douglas-fir planted within the non-analogous climate conditions of Central and continental Europe. With data from 50 common garden trials, we developed Universal Response Functions (URF) for tree height and mean basal area and compared the growth performance of the selected best performing populations with that of populations identified through a climate envelope approach. Climate variables of the trial location were found to be stronger predictors of growth performance than climate variables of the population origin. Although the precipitation regime of the population sources varied strongly none of the precipitation related climate variables of population origin was found to be significant within the models. Overall, the URFs explained more than 88% of variation in growth performance. Populations identified by the URF models originate from western Cascades and coastal areas of Washington and Oregon and show significantly higher growth performance than populations identified by the climate envelope approach under both current and climate change scenarios. The URFs predict decreasing growth performance at low and middle elevations of the case study area, but increasing growth performance on high elevation sites. Our analysis suggests that population recommendations based on empirical approaches should be preferred and population selections by climate envelope models without considering climatic constrains of growth performance should be carefully appraised before

  15. Cryogenic surface ion traps

    International Nuclear Information System (INIS)

    Niedermayr, M.

    2015-01-01

    Microfabricated surface traps are a promising architecture to realize a scalable quantum computer based on trapped ions. In principle, hundreds or thousands of surface traps can be located on a single substrate in order to provide large arrays of interacting ions. To this end, trap designs and fabrication methods are required that provide scalable, stable and reproducible ion traps. This work presents a novel surface-trap design developed for cryogenic applications. Intrinsic silicon is used as the substrate material of the traps. The well-developed microfabrication and structuring methods of silicon are utilized to create simple and reproducible traps. The traps were tested and characterized in a cryogenic setup. Ions could be trapped and their life time and motional heating were investigated. Long ion lifetimes of several hours were observed and the measured heating rates were reproducibly low at around 1 phonon per second at a trap frequency of 1 MHz. (author) [de

  16. Flexible cryogenic conduit

    International Nuclear Information System (INIS)

    Brindza, P.D.; Wines, R.R.; Takacs, J.J.

    1999-01-01

    A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament

  17. Cryogenics for SMES

    International Nuclear Information System (INIS)

    McIntosh, G.E.

    1981-01-01

    A wide-ranging study of superconducting magnetic energy storage (SMES) structural and cryogenic requirements was made. Concepts and computational methods have been developed for all of the major problems in these areas. Design analyses have been made to provide more detailed information on some items and experimental work has been performed to create data bases in the areas of superfluid heat transfer, superfluid dielectric properties, heat transfer from conductors, and in the thermal and mechanical properties of materials at low temperatures. In most cases optimum solutions have not been made because of the developing nature of the overall study but methodology for optimization has been worked out for essentially all SMES cryogenic and structural elements. The selection of 1.8 K cooling and all aluminum systems in bedrock continues to be the best choice

  18. Cryogenic treatment of gas

    Science.gov (United States)

    Bravo, Jose Luis [Houston, TX; Harvey, III, Albert Destrehan; Vinegar, Harold J [Bellaire, TX

    2012-04-03

    Systems and methods of treating a gas stream are described. A method of treating a gas stream includes cryogenically separating a first gas stream to form a second gas stream and a third stream. The third stream is cryogenically contacted with a carbon dioxide stream to form a fourth and fifth stream. A majority of the second gas stream includes methane and/or molecular hydrogen. A majority of the third stream includes one or more carbon oxides, hydrocarbons having a carbon number of at least 2, one or more sulfur compounds, or mixtures thereof. A majority of the fourth stream includes one or more of the carbon oxides and hydrocarbons having a carbon number of at least 2. A majority of the fifth stream includes hydrocarbons having a carbon number of at least 3 and one or more of the sulfur compounds.

  19. Chemiluminescence in cryogenic matrices

    Science.gov (United States)

    Lotnik, S. V.; Kazakov, Valeri P.

    1989-04-01

    The literature data on chemiluminescence (CL) in cryogenic matrices have been classified and correlated for the first time. The role of studies on phosphorescence and CL at low temperatures in the development of cryochemistry is shown. The features of low-temperature CL in matrices of nitrogen and inert gases (fine structure of spectra, matrix effects) and the data on the mobility and reactivity of atoms and radicals at very low temperatures are examined. The trends in the development of studies on CL in cryogenic matrices, such as the search for systems involving polyatomic molecules and extending the forms of CL reactions, are followed. The reactions of active nitrogen with hydrocarbons that are accompanied by light emission and CL in the oxidation of carbenes at T >= 77 K are examined. The bibliography includes 112 references.

  20. Cryogenic cooler thermal coupler

    International Nuclear Information System (INIS)

    Green, K.E.; Talbourdet, J.A.

    1984-01-01

    A thermal coupler assembly mounted to the coldfinger of a cryogenic cooler which provides improved thermal transfer between the coldfinger and the detector assembly mounted on the dewar endwell. The thermal coupler design comprises a stud and spring-loaded cap mounted on the coldfinger assembly. Thermal transfer is made primarily through the air space between the cap and coldwell walls along the radial surfaces. The cap is spring loaded to provide thermal contact between the cap and endwell end surfaces

  1. Cryogenic high current discharges

    International Nuclear Information System (INIS)

    Meierovich, B.E.

    1994-01-01

    Z-pinches formed from frozen deuterium fibers by a rapidly rising current have enhanced stability and high neutron yield. The efforts to understand the enhanced stability and neutron yield on the basis of classical picture of Bennett equilibrium of the current channel has not given satisfactory results. The traditional approach does not take into account the essential difference between the frozen deuterium fiber Z-pinches and the usual Z-pinches such as exploding wires or classical gas-puffed Z-pinches. The very low temperature of the fiber atoms (10 K), together with the rapidly rising current, result in the coexistence of a high current channel with unionized fiber atoms for a substantial period of time. This phenomena lasts during the risetime. This approach takes into account the difference of the breakdown in a dielectric deuterium fiber and the breakdown in a metallic wire. This difference is essential to the understanding of specific features of cryogenic high current discharges. Z-pinches in frozen deuterium fibers should be considered as a qualitatively new phenomenon on the boundary of cryogenic and high current physics. It is a start of a new branch in plasma physics: the physics of cryogenic high current discharges

  2. CEBAF cryogenic system

    International Nuclear Information System (INIS)

    Brindza, P.; Rode, C.

    1986-01-01

    The Continuous Electron Beam Accelerator Facility (CEBAF) is a standing wave superconducting linear accelerator with a maximum energy of 4 GeV and 200 μA beam current. The 418 Cornell/CEBAF superconducting niobium accelerating cavities are arranged in two 0.5 GeV linacs with magnetic recirculating arcs at each end. These accelerating cavities are arranged in pairs in a cryounit. The ensemble of four cryounits (8 cavities) together with their end caps makes up a complete cryostat called a cryogenic module. The four cryounit helium vessels are cross connected to each other and share a common cryogen supply, radiation shield and insulating vacuum. The cryogenics system for CEBAF consists of a 5kW central helium refrigerator and a transfer line system to supply 2.2 K 2.8 ATM helium to the cavity cryostats, 40 K helium at 3.5 ATM to the radiation shields and 4.5K helium at 2.8 ATM to the superconducting magnetic spectrometers in the experimental halls. Both the 2.2 K and the 4.5 K helium are expanded by Joule-Thompson (JT) valves in the individual cryostats yielding 2.0 K at .031 ATM and 4.4 K at 1.2 ATM respectively. The Central Helium Refrigerator is located in the center of the CEBAF racetrack with the transfer lines located in the linac tunnels

  3. Cryogenics in nuclear reactor technology

    International Nuclear Information System (INIS)

    Dharmadurai, G.

    1982-01-01

    The cryogenic technology has significantly contributed to the development of several proven techniques for use in the nuclear power industry. A noteworthy feature is the unique role of cryogenics in minimising the release of radioactive and some chemical pollutants to the environment during the operation of various plants associated with this industry. The salient technological features of several cryogenic processes relevant to the nuclear reactor technology are discussed. (author)

  4. Feasibility Study of Cryogenic Cutting Technology by Using a Computer Simulation and Manufacture of Main Components for Cryogenic Cutting System

    International Nuclear Information System (INIS)

    Kim, Sung Kyun; Lee, Dong Gyu; Lee, Kune Woo; Song, Oh Seop

    2009-01-01

    Cryogenic cutting technology is one of the most suitable technologies for dismantling nuclear facilities due to the fact that a secondary waste is not generated during the cutting process. In this paper, the feasibility of cryogenic cutting technology was investigated by using a computer simulation. In the computer simulation, a hybrid method combined with the SPH (smoothed particle hydrodynamics) method and the FE (finite element) method was used. And also, a penetration depth equation, for the design of the cryogenic cutting system, was used and the design variables and operation conditions to cut a 10 mm thickness for steel were determined. Finally, the main components of the cryogenic cutting system were manufactures on the basis of the obtained design variables and operation conditions.

  5. Terrestrial Spaceflight Analogs: Antarctica

    Science.gov (United States)

    Crucian, Brian

    2013-01-01

    Alterations in immune cell distribution and function, circadian misalignment, stress and latent viral reactivation appear to persist during Antarctic winterover at Concordia Station. Some of these changes are similar to those observed in Astronauts, either during or immediately following spaceflight. Others are unique to the Concordia analog. Based on some initial immune data and environmental conditions, Concordia winterover may be an appropriate analog for some flight-associated immune system changes and mission stress effects. An ongoing smaller control study at Neumayer III will address the influence of the hypoxic variable. Changes were observed in the peripheral blood leukocyte distribution consistent with immune mobilization, and similar to those observed during spaceflight. Alterations in cytokine production profiles were observed during winterover that are distinct from those observed during spaceflight, but potentially consistent with those observed during persistent hypobaric hypoxia. The reactivation of latent herpesviruses was observed during overwinter/isolation, that is consistently associated with dysregulation in immune function.

  6. Cryogenic implications for DT

    International Nuclear Information System (INIS)

    Souers, P.C.

    1977-10-01

    Cryogenic hydrogen data is being compiled for magnetic fusion engineering. Many physical properties of DT can be extrapolated from H 2 and D 2 values. The phase diagram properties of the D 2 -DT-T 2 mixture are being measured. Three properties which will be greatly affected by tritium should be measured. In order of their perceived importance, they are: (1) solid thermal conductivity, (2) solid mechanical strength, and (3) gaseous electrical conductivity. The most apparent need for DT data is in Tokomak fuel pellet injection. Cryopumping and distillation applications are also considered

  7. Kodak AMSD Cryogenic Test Plans

    Science.gov (United States)

    Matthews, Gary; Hammon, John; Barrett, David; Russell, Kevin (Technical Monitor)

    2002-01-01

    NGST will be an IR based optical system that will operate at cryogenic temperatures. As part of the AMSD program, Kodak must demonstrate the ability of our system to perform at these very cold temperatures. Kodak will discuss the test approach that will be used for cryogenic testing at MSFC's XRCF.

  8. Cryogenic forced convection refrigerating system

    International Nuclear Information System (INIS)

    Klee, D.J.

    1988-01-01

    This patent describes the method of refrigerating products by contact with a refrigerating gas which comprises introducing product into a refrigeration zone, contacting the product with the refrigerating gas for a sufficient time to refrigerate it to the appropriate extent and removing the refrigerated product. The improvement for producing the refrigeration gas from a liquid cryogen such that essentially all of the liquid cryogen is fully vaporized before contacting the product comprises: (a) introducing the liquid cryogen, selected from the group consisting of liquid air and liquid nitrogen, at elevated pressure into an ejector as the motive fluid to accelerate a portion of a warm refrigerating gas through the ejector while mixing the cryogen and gas to effect complete vaporization of the liquid cryogen and substantial cooling of the portion of the refrigerating gas resulting in a cold discharge gas which is above the liquefaction temperature of the cryogen; (b) introducing the cold discharge gas into a forced circulation pathway of refrigerating gas and producing a cold refrigerating gas which contacts and refrigerates product and is then at least partially recirculated; (c) sensing the temperature of the refrigerating gas in the forced circulation pathway and controlling the introduction of liquid cryogen with regard to the sensed temperature to maintain the temperature of the discharge gas above the liquefacton temperature of the cryogen utilized

  9. Cryogenics in CEBAF HMS dipole

    International Nuclear Information System (INIS)

    Bogensberger, P.; Ramsauer, F.; Brindza, P.; Wines, R.; Koefler, H.

    1994-01-01

    The paper will report upon the final design, manufacturing and tests of CEBAF's HMS Dipole cryogenic equipment. The liquid nitrogen circuits, the helium circuits and thermal insulation of the magnet will be addressed. The cryogenic reservoir and control module as an integral part of the HMS Dipole magnet will be presented. The construction, manufacturing, tests and final performance of the HMS Dipole cryogenic system will be reported. The LN 2 circuit and the He circuit are tied together by the control system for cool down, normal operation and standby. This system monitors proper temperature differences between both circuits and controls the cryogenic supply to meet the constraints. Implementation of the control features for the cryogenic system into the control system will be reported

  10. Cryogenic system for a superconducting spectrometer

    International Nuclear Information System (INIS)

    Porter, J.

    1983-03-01

    The Heavy Ion Spectrometer System (HISS) relies upon superconducting coils of cryostable, pool boiling design to provide a maximum particle bending field of 3 tesla. This paper describes the cryogenic facility including helium refrigeration, gas management, liquid nitrogen system, and the overall control strategy. The system normally operates with a 4 K heat load of 150 watts; the LN 2 circuits absorb an additional 4000 watts. 80K intercept control is by an LSI 11 computer. Total available refrigeration at 4K is 400 watts using reciprocating expanders at the 20K and 4K level. The minicomputer has the capability of optimizing overall utility input cost by varying operating points. A hybrid of pneumatic, analog, and digital control is successful in providing full time unattended operation. The 7m diameter magnet/cryostat assembly is rotatable through 180 degrees to provide a variety of spectrometer orientations

  11. A cryogenic multichannel electronically scanned pressure module

    Science.gov (United States)

    Shams, Qamar A.; Fox, Robert L.; Adcock, Edward E.; Kahng, Seun K.

    1992-01-01

    Consideration is given to a cryogenic multichannel electronically scanned pressure (ESP) module developed and tested over an extended temperature span from -184 to +50 C and a pressure range of 0 to 5 psig. The ESP module consists of 32 pressure sensor dice, four analog 8 differential-input multiplexers, and an amplifier circuit, all of which are packaged in a physical volume of 2 x 1 x 5/8 in with 32 pressure and two reference ports. Maximum nonrepeatability is measured at 0.21 percent of full-scale output. The ESP modules have performed consistently well over 15 times over the above temperature range and continue to work without any sign of degradation. These sensors are also immune to repeated thermal shock tests over a temperature change of 220 C/sec.

  12. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel J M

    2010-01-01

    The design of an analog-to-digital converter or digital-to-analog converter is one of the most fascinating tasks in micro-electronics. In a converter the analog world with all its intricacies meets the realm of the formal digital abstraction. Both disciplines must be understood for an optimum conversion solution. In a converter also system challenges meet technology opportunities. Modern systems rely on analog-to-digital converters as an essential part of the complex chain to access the physical world. And processors need the ultimate performance of digital-to-analog converters to present the results of their complex algorithms. The same progress in CMOS technology that enables these VLSI digital systems creates new challenges for analog-to-digital converters: lower signal swings, less power and variability issues. Last but not least, the analog-to-digital converter must follow the cost reduction trend. These changing boundary conditions require micro-electronics engineers to consider their design choices for...

  13. ODH, oxygen deficiency hazard cryogenic analysis

    International Nuclear Information System (INIS)

    Augustynowicz, S.D.

    1994-01-01

    An oxygen deficiency exists when the concentration of oxygen, by volume, drops to a level at which atmosphere supplying respiratory protection must be provided. Since liquid cryogens can expand by factors of 700 (LN 2 ) to 850 (LH e ), the uncontrolled release into an enclosed space can easily cause an oxygen-deficient condition. An oxygen deficiency hazard (ODH) fatality rate per hour (OE) is defined as: OE = Σ N i P i F i , where N i = number of components, P i = probability of failure or operator error, and F i = fatality factor. ODHs range from open-quotes unclassifiedclose quotes (OE -9 1/h) to class 4, which is the most hazardous (OE>10 -1 1/h). For Superconducting Super Collider Laboratory (SSCL) buildings where cryogenic systems exist, failure rate, fatality factor, reduced oxygen ratio, and fresh air circulation are examined

  14. Hydrogen isotope separation by cryogenic distillation method

    International Nuclear Information System (INIS)

    Hayakawa, Nobuo; Mitsui, Jin

    1987-01-01

    Hydrogen isotope separation in fusion fuel cycle and tritium recovery from heavy water reactor are very important, and therefore the early establishment of these separation techniques are desired. The cryogenic distillation method in particular is promising for the separation of hydrogen isotope and the recovery of high concentrated tritium. The studies of hydrogen isotope separation by cryogenic distillation method have been carried out by using the experimental apparatus made for the first time in Japan. The separation of three components (H 2 -HD-D 2 ) under total reflux conditions was got by using the packing tower of 500 mm height. It was confirmed that the Height Equivalent Theoretical Plate (HETP) was 20 - 30 mm for the vapor's line velocity of 20 - 80 mm/s. (author)

  15. Temperature Stratification in a Cryogenic Fuel Tank

    Science.gov (United States)

    Daigle, Matthew John; Smelyanskiy, Vadim; Boschee, Jacob; Foygel, Michael Gregory

    2013-01-01

    A reduced dynamical model describing temperature stratification effects driven by natural convection in a liquid hydrogen cryogenic fuel tank has been developed. It accounts for cryogenic propellant loading, storage, and unloading in the conditions of normal, increased, and micro- gravity. The model involves multiple horizontal control volumes in both liquid and ullage spaces. Temperature and velocity boundary layers at the tank walls are taken into account by using correlation relations. Heat exchange involving the tank wall is considered by means of the lumped-parameter method. By employing basic conservation laws, the model takes into consideration the major multi-phase mass and energy exchange processes involved, such as condensation-evaporation of the hydrogen, as well as flows of hydrogen liquid and vapor in the presence of pressurizing helium gas. The model involves a liquid hydrogen feed line and a tank ullage vent valve for pressure control. The temperature stratification effects are investigated, including in the presence of vent valve oscillations. A simulation of temperature stratification effects in a generic cryogenic tank has been implemented in Matlab and results are presented for various tank conditions.

  16. Creep behavior of an epoxy resin and an epoxy-based FRP in condition of simultaneous supply of radiation and stress at cryogenic temperatures

    International Nuclear Information System (INIS)

    Nishiura, Tetsuya; Nishijima, Shigehiro; Okada, Toichi

    1995-01-01

    Creep tests of an epoxy resin and an epoxy-based FRP in bending under irradiation condition have been carried out, to investigate the synergistic effects of radiation and stress on mechanical properties of FRP. Simultaneous supply of stress and irradiation on the epoxy resin and the FRP enhanced creep rates in comparison with that supply of the stress on a post-irradiated one did. ESR spectra measurement was also carried out to study the change of molecule of the resin irradiated. Increase of molecular weight between crosslinks was found out to be enhanced by the synergistic effect of radiation and stress. The mechanism of increased damage of FRP induced by the effects of simultaneous stress and irradiation is discussed. (author)

  17. Cryogenic Preamplifiers for Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Johansen, Daniel H.; Sanchez-Heredia, Juan D.; Petersen, Jan R.

    2018-01-01

    Pursuing the ultimate limit of detection in magnetic resonance imaging (MRI) requires cryogenics to decrease the thermal noise of the electronic circuits. As cryogenic coils for MRI are slowly emerging cryogenic preamplifiers are required to fully exploit their potential. A cryogenic preamplifier...

  18. Cryogenic Insulation Standard Data and Methodologies Project

    Science.gov (United States)

    Summerfield, Burton; Thompson, Karen; Zeitlin, Nancy; Mullenix, Pamela; Fesmire, James; Swanger, Adam

    2015-01-01

    Extending some recent developments in the area of technical consensus standards for cryogenic thermal insulation systems, a preliminary Inter-Laboratory Study of foam insulation materials was performed by NASA Kennedy Space Center and LeTourneau University. The initial focus was ambient pressure cryogenic boil off testing using the Cryostat-400 flat-plate instrument. Completion of a test facility at LETU has enabled direct, comparative testing, using identical cryostat instruments and methods, and the production of standard thermal data sets for a number of materials under sub-ambient conditions. The two sets of measurements were analyzed and indicate there is reasonable agreement between the two laboratories. Based on cryogenic boiloff calorimetry, new equipment and methods for testing thermal insulation systems have been successfully developed. These boiloff instruments (or cryostats) include both flat plate and cylindrical models and are applicable to a wide range of different materials under a wide range of test conditions. Test measurements are generally made at large temperature difference (boundary temperatures of 293 K and 78 K are typical) and include the full vacuum pressure range. Results are generally reported in effective thermal conductivity (ke) and mean heat flux (q) through the insulation system. The new cryostat instruments provide an effective and reliable way to characterize the thermal performance of materials under subambient conditions. Proven in through thousands of tests of hundreds of material systems, they have supported a wide range of aerospace, industry, and research projects. Boiloff testing technology is not just for cryogenic testing but is a cost effective, field-representative methodology to test any material or system for applications at sub-ambient temperatures. This technology, when adequately coupled with a technical standards basis, can provide a cost-effective, field-representative methodology to test any material or system

  19. Science Teachers' Analogical Reasoning

    Science.gov (United States)

    Mozzer, Nilmara Braga; Justi, Rosária

    2013-08-01

    Analogies can play a relevant role in students' learning. However, for the effective use of analogies, teachers should not only have a well-prepared repertoire of validated analogies, which could serve as bridges between the students' prior knowledge and the scientific knowledge they desire them to understand, but also know how to introduce analogies in their lessons. Both aspects have been discussed in the literature in the last few decades. However, almost nothing is known about how teachers draw their own analogies for instructional purposes or, in other words, about how they reason analogically when planning and conducting teaching. This is the focus of this paper. Six secondary teachers were individually interviewed; the aim was to characterize how they perform each of the analogical reasoning subprocesses, as well as to identify their views on analogies and their use in science teaching. The results were analyzed by considering elements of both theories about analogical reasoning: the structural mapping proposed by Gentner and the analogical mechanism described by Vosniadou. A comprehensive discussion of our results makes it evident that teachers' content knowledge on scientific topics and on analogies as well as their pedagogical content knowledge on the use of analogies influence all their analogical reasoning subprocesses. Our results also point to the need for improving teachers' knowledge about analogies and their ability to perform analogical reasoning.

  20. Cryogenic Tracking Detectors

    CERN Multimedia

    Luukka, P R; Tuominen, E M; Mikuz, M

    2002-01-01

    The recent advances in Si and diamond detector technology give hope of a simple solution to the radiation hardness problem for vertex trackers at the LHC. In particular, we have recently demonstrated that operating a heavily irradiated Si detector at liquid nitrogen (LN$_2$) temperature results in significant recovery of Charge Collection Efficiency (CCE). Among other potential benefits of operation at cryogenic temperatures are the use of large low-resistivity wafers, simple processing, higher and faster electrical signal because of higher mobility and drift velocity of carriers, and lower noise of the readout circuit. A substantial reduction in sensor cost could result The first goal of the approved extension of the RD39 program is to demonstrate that irradiation at low temperature in situ during operation does not affect the results obtained so far by cooling detectors which were irradiated at room temperature. In particular we shall concentrate on processes and materials that could significantly reduce th...

  1. Cryogenic Cam Butterfly Valve

    Science.gov (United States)

    McCormack, Kenneth J. (Inventor)

    2016-01-01

    A cryogenic cam butterfly valve has a body that includes an axially extending fluid conduit formed there through. A disc lug is connected to a back side of a valve disc and has a circular bore that receives and is larger than a cam of a cam shaft. The valve disc is rotatable for a quarter turn within the body about a lug axis that is offset from the shaft axis. Actuating the cam shaft in the closing rotational direction first causes the camming side of the cam of the cam shaft to rotate the disc lug and the valve disc a quarter turn from the open position to the closed position. Further actuating causes the camming side of the cam shaft to translate the valve disc into sealed contact with the valve seat. Opening rotational direction of the cam shaft reverses these motions.

  2. Influence of Thermal Cycling on Cryogenic Thermometers

    CERN Document Server

    Balle, C; Rieubland, Jean Michel; Suraci, A; Togny, F; Vauthier, N

    1999-01-01

    The stringent requirements on temperature control of the superconducting magnets for the Large Hadron Collider (LHC), impose that the cryogenic temperature sensors meet compelling demands such as long-term stability, radiation hardness, readout accuracy better than 5 mK at 1.8 K and compatibility with industrial control equipment. This paper presents the results concerning long-term stability of resistance temperature sensors submitted to cryogenic thermal cycles. For this task a simple test facility has been designed, constructed and put into operation for cycling simultaneously 115 cryogenic thermometers between 300 K and 4.2 K. A thermal cycle is set to last 71/4 hours: 3 hours for either cooling down or warming up the sensors and 1 respectively 1/4 hour at steady temperature conditions at each end of the temperature cycle. A Programmable Logic Controller (PLC) drives automatically this operation by reading 2 thermometers and actuating on 3 valves and 1 heater. The first thermal cycle was accomplished in a...

  3. Cryogenic characterization of LEDs for space application

    Science.gov (United States)

    Carron, Jérôme; Philippon, Anne; How, Lip Sun; Delbergue, Audrey; Hassanzadeh, Sahar; Cillierre, David; Danto, Pascale; Boutillier, Mathieu

    2017-09-01

    In the frame of EUCLID project, the Calibration Unit of the VIS (VISible Imager) instrument must provide an accurate and well characterized light source for in-flight instrument calibration without noise when it is switched off. The Calibration Unit consists of a set of LEDs emitting at various wavelengths in the visible towards an integrating sphere. The sphere's output provides a uniform illumination over the entire focal plane. Nine references of LEDs from different manufacturers were selected, screened and qualified under cryogenic conditions. Testing this large quantity of samples led to the implementation of automated testing equipment with complete in-situ monitoring of optoelectronic parameters as well as temperature and vacuum values. All the electrical and optical parameters of the LED have been monitored and recorded at ambient and cryogenic temperatures. These results have been compiled in order to show the total deviation of the LED electrical and electro-optical properties in the whole mission and to select the best suitable LED references for the mission. This qualification has demonstrated the robustness of COTS LEDs to operate at low cryogenic temperatures and in the space environment. Then 6 wavelengths were selected and submitted to an EMC sensitivity test at room and cold temperature by counting the number of photons when LEDs drivers are OFF. Characterizations were conducted in the full frequency spectrum in order to implement solutions at system level to suppress the emission of photons when the LED drivers are OFF. LEDs impedance was also characterized at room temperature and cold temperature.

  4. Properties of strain gages at cryogenic temperature

    International Nuclear Information System (INIS)

    Shibata, Nobuo; Fujiyoshi, Toshimitsu.

    1978-01-01

    At the time of developing superconduction generators, the stress measurement for rotor parts is required to grasp the safety and performance of the rotor at cryogenic temperature, which is cooled with liquid helium. In case of carrying out the stress measurement with strain gages, the problems are as follows. The strain gages and lead wires are exposed to cryogenic temperature from 4 to 10 K and strong magnetic field of about 3T, and subjected to high centrifugal acceleration of about 500G. In order to establish the techniques of the stress measurement under such conditions, the adhesives and damp-proof coatings for strain gages and strain gages themselves in Japan and foreign countries were examined on the properties at cryogenic temperature. As for the properties of strain gages, mainly the apparent strain owing to temperature change was investigated, and the change of the gage factors was studies only at liquid nitrogen temperature. The stress measurement with strain gages at low temperature had been studied in detail down to liquid nitrogen temperature concerning LNG tanks. The experimental apparatus, the samples, the testing methods and the test results of cooling tests on adhesives and damp-proof coatings, and the temperature characteristics of strain gages are reported. The usable adhesives and coatings were found, and correction by accurate temperature measurement is required for apparent strain. (Kako, I.)

  5. Cryogenic Propellant Storage and Transfer

    Data.gov (United States)

    National Aeronautics and Space Administration — Space Flight Demonstration development has been canceled in favor of a ground test bed development for of passive/active cryogenic propellant storage, transfer, and...

  6. Baseline Configuration of the Cryogenic System for the International Linear Collider

    CERN Document Server

    Casas-Cubillos, J; Claudet, S; Ganni, R; Klebaner, A; Parma, V; Peterson, T; Riddone, G; Rode, C; Rousset, B; Serio, L; Tavian, L; Theilacker, J; Vullierme, B; Van Weelderen, R; Weisend, J

    2007-01-01

    The paper discusses the main constraints and boundary conditions and describes the baseline configuration of the International Linear Collider (ILC) cryogenic system. The cryogenic layout, architecture and the cooling principle are presented. The paper addresses a plan for study and development required to demonstrate and improve the performance, to reduce cost and to attain the desired reliability.

  7. Intuitive analog circuit design

    CERN Document Server

    Thompson, Marc

    2013-01-01

    Intuitive Analog Circuit Design outlines ways of thinking about analog circuits and systems that let you develop a feel for what a good, working analog circuit design should be. This book reflects author Marc Thompson's 30 years of experience designing analog and power electronics circuits and teaching graduate-level analog circuit design, and is the ideal reference for anyone who needs a straightforward introduction to the subject. In this book, Dr. Thompson describes intuitive and ""back-of-the-envelope"" techniques for designing and analyzing analog circuits, including transistor amplifi

  8. Cryogenic, Absolute, High Pressure Sensor

    Science.gov (United States)

    Chapman, John J. (Inventor); Shams. Qamar A. (Inventor); Powers, William T. (Inventor)

    2001-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  9. Cryogenic High Pressure Sensor Module

    Science.gov (United States)

    Chapman, John J. (Inventor); Shams, Qamar A. (Inventor); Powers, William T. (Inventor)

    1999-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  10. Cryogenic foam insulation: Abstracted publications

    Science.gov (United States)

    Williamson, F. R.

    1977-01-01

    A group of documents were chosen and abstracted which contain information on the properties of foam materials and on the use of foams as thermal insulation at cryogenic temperatures. The properties include thermal properties, mechanical properties, and compatibility properties with oxygen and other cryogenic fluids. Uses of foams include applications as thermal insulation for spacecraft propellant tanks, and for liquefied natural gas storage tanks and pipelines.

  11. A Piezoelectric Cryogenic Heat Switch

    Science.gov (United States)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-01-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

  12. (abstract) Simple Spreadsheet Thermal Models for Cryogenic Applications

    Science.gov (United States)

    Nash, A. E.

    1994-01-01

    Self consistent circuit analog thermal models, that can be run in commercial spreadsheet programs on personal computers, have been created to calculate the cooldown and steady state performance of cryogen cooled Dewars. The models include temperature dependent conduction and radiation effects. The outputs of the models provide temperature distribution and Dewar performance information. These models have been used to analyze the Cryogenic Telescope Test Facility (CTTF). The facility will be on line in early 1995 for its first user, the Infrared Telescope Technology Testbed (ITTT), for the Space Infrared Telescope Facility (SIRTF) at JPL. The model algorithm as well as a comparison of the model predictions and actual performance of this facility will be presented.

  13. On-board cryogenic system for magnetic levitation of trains

    Energy Technology Data Exchange (ETDEWEB)

    Baldus, S A.W.; Kneuer, R; Stephan, A

    1975-02-01

    An experimental car based on electrodynamic levitation with superconducting magnets was developed and manufactured with an on-board cryogenic system. This system has to cope with new conditions and cryogenic tasks. It can be characterized in principle by liquid helium heat exchanger units, compressors, transfer lines, rotable and movable couplings and junctions. All transfer lines and couplings consist of three coaxial ducts for three different streams. Processes and components are discussed, and a brief description of the first results for the whole system under simulation conditions is given.

  14. On-board cryogenic system for magnetic levitation of trains

    International Nuclear Information System (INIS)

    Asztalos, St.; Baldus, W.; Kneuer, R.; Stephan, A.

    1974-01-01

    An experimental car based on electrodynamic levitation with superconducting magnets has been developed and manufactured by AEG, BBC, Siemens and other partners, together with Linde AG as the firm responsible for the on-board cryogenic system. This system has to cope with new conditions and cryogenic tasks. It can be characterized in principle by liquid helium heat exchanger units, compressors, transfer lines, rotatable and movable couplings and junctions. All transfer lines and couplings consist of three coaxial ducts for three different streams. This paper reports on processes and components. A brief description of the first results for the whole system under simulation conditions is given. (author)

  15. Evaluation of Losses Of Cold Energy of Cryogen Products in The Transport Systems

    Science.gov (United States)

    Uglanov, Dmitry; Sarmin, Dmitry; Tsapkova, Alexandra; Burdina, Yana

    2017-12-01

    At present, there are problems of energy saving in various areas of human life and in power complexes of industrial plants. One possible solution to the problem of increasing energy efficiency is the use of liquefied natural gas and its cold energy. Pipelines for fuel or gas supply in cryogen supply systems have different length depending on the mutual position of storage and cryogen consumption devices relatively to a start construction. Cryogen supply and transport systems include a lot of fittings of different assortment. Reservoirs can be installed on different elevation points. To reduce heat inleak and decrease cold energy of cryogen product different kinds of thermal insulation are used. Cryogen pipelines provide required operation conditions of storage and gasifying systems. The aim of the thermal calculation of cryogen transport and supply systems is to define the value of cryogen heat. In this paper it is shown values of cryogen temperature rise due to heat inleaks at cryogen’s transfer along transport systems for ethane, methane, oxygen and nitrogen were calculated. Heat inleaks also due to hydraulic losses were calculated. Specific losses of cold energy of cryogen product for laminar and turbulent flow were calculated. Correspondences of temperature rise, critical pipeline’s length and Reynolds number were defined for nitrogen, argon, methane and oxygen.

  16. Cryogenic Moisture Uptake in Foam Insulation for Space Launch Vehicles

    Science.gov (United States)

    Fesmire, James E.; ScholtensCoffman, Brekke E.; Sass, Jared P.; Williams, Martha K.; Smith, Trent M.; Meneghelli, Barrry J.

    2008-01-01

    Rigid polyurethane foams and rigid polyisocyanurate foams (spray-on foam insulation), like those flown on Shuttle, Delta IV, and will be flown on Ares-I and Ares-V, can gain an extraordinary amount of water when under cryogenic conditions for several hours. These foams, when exposed for eight hours to launch pad environments on one side and cryogenic temperature on the other, increase their weight from 35 to 80 percent depending on the duration of weathering or aging. This effect translates into several thousand pounds of additional weight for space vehicles at lift-off. A new cryogenic moisture uptake apparatus was designed to determine the amount of water/ice taken into the specimen under actual-use propellant loading conditions. This experimental study included the measurement of the amount of moisture uptake within different foam materials. Results of testing using both aged specimens and weathered specimens are presented. To better understand cryogenic foam insulation performance, cryogenic moisture testing is shown to be essential. The implications for future launch vehicle thermal protection system design and flight performance are discussed.

  17. Rhetoric and analogies

    OpenAIRE

    Aragonès, Enriqueta; Gilboa, Itzhak; Postlewaite, Andrew; Schmeidler, David; Universitat Autònoma de Barcelona. Unitat de Fonaments de l'Anàlisi Econòmica; Universitat Autònoma de Barcelona. Institut d'Anàlisi Econòmica

    2013-01-01

    The art of rhetoric may be defined as changing other people's minds (opinions, beliefs) without providing them new information. One tech- nique heavily used by rhetoric employs analogies. Using analogies, one may draw the listener's attention to similarities between cases and to re-organize existing information in a way that highlights certain reg- ularities. In this paper we offer two models of analogies, discuss their theoretical equivalence, and show that finding good analogies is a com- p...

  18. Analog techniques in CEBAF's RF control system

    International Nuclear Information System (INIS)

    Hovater, C.; Fugitt, J.

    1989-01-01

    Recent developments in high-speed analog technology have progressed into the areas of traditional RF technology. Diode related devices are being replaced by analog IC's in the CEBAF RF control system. Complex phase modulators and attenuators have been successfully tested at 70 MHz. They have three advantages over existing technology: lower cost, less temperature sensitivity, and more linearity. RF signal conditioning components and how to implement the new analog IC's will be covered in this paper. 4 refs., 5 figs

  19. Analog techniques in CEBAF'S RF control system

    International Nuclear Information System (INIS)

    Hovater, C.; Fugitt, J.

    1989-01-01

    Recent developments in high-speed analog technology have progressed into the areas of traditional rf technology. Diode-related devices are being replaced by analog IC's in the CEBAF rf control system. Complex phase modulators and attenuators have been successfully tested at 70 MHz. They have three advantages over existing technology: lower cost, less temperature sensitivity, and more linearity. Rf signal conditioning components and how to implement the new analog IC's will be covered in this paper. 4 refs., 5 figs

  20. Cryogenic Liquid Sample Acquisition System for Remote Space Applications

    Science.gov (United States)

    Mahaffy, Paul; Trainer, Melissa; Wegel, Don; Hawk, Douglas; Melek, Tony; Johnson, Christopher; Amato, Michael; Galloway, John

    2013-01-01

    There is a need to acquire autonomously cryogenic hydrocarbon liquid sample from remote planetary locations such as the lakes of Titan for instruments such as mass spectrometers. There are several problems that had to be solved relative to collecting the right amount of cryogenic liquid sample into a warmer spacecraft, such as not allowing the sample to boil off or fractionate too early; controlling the intermediate and final pressures within carefully designed volumes; designing for various particulates and viscosities; designing to thermal, mass, and power-limited spacecraft interfaces; and reducing risk. Prior art inlets for similar instruments in spaceflight were designed primarily for atmospheric gas sampling and are not useful for this front-end application. These cryogenic liquid sample acquisition system designs for remote space applications allow for remote, autonomous, controlled sample collections of a range of challenging cryogenic sample types. The design can control the size of the sample, prevent fractionation, control pressures at various stages, and allow for various liquid sample levels. It is capable of collecting repeated samples autonomously in difficult lowtemperature conditions often found in planetary missions. It is capable of collecting samples for use by instruments from difficult sample types such as cryogenic hydrocarbon (methane, ethane, and propane) mixtures with solid particulates such as found on Titan. The design with a warm actuated valve is compatible with various spacecraft thermal and structural interfaces. The design uses controlled volumes, heaters, inlet and vent tubes, a cryogenic valve seat, inlet screens, temperature and cryogenic liquid sensors, seals, and vents to accomplish its task.

  1. Cryogenic Electric Motor Tested

    Science.gov (United States)

    Brown, Gerald V.

    2004-01-01

    Technology for pollution-free "electric flight" is being evaluated in a number of NASA Glenn Research Center programs. One approach is to drive propulsive fans or propellers with electric motors powered by fuel cells running on hydrogen. For large transport aircraft, conventional electric motors are far too heavy to be feasible. However, since hydrogen fuel would almost surely be carried as liquid, a propulsive electric motor could be cooled to near liquid hydrogen temperature (-423 F) by using the fuel for cooling before it goes to the fuel cells. Motor windings could be either superconducting or high purity normal copper or aluminum. The electrical resistance of pure metals can drop to 1/100th or less of their room-temperature resistance at liquid hydrogen temperature. In either case, super or normal, much higher current density is possible in motor windings. This leads to more compact motors that are projected to produce 20 hp/lb or more in large sizes, in comparison to on the order of 2 hp/lb for large conventional motors. High power density is the major goal. To support cryogenic motor development, we have designed and built in-house a small motor (7-in. outside diameter) for operation in liquid nitrogen.

  2. Cryogenic Permanent Magnet Undulators

    International Nuclear Information System (INIS)

    Chavanne, J.; Lebec, G.; Penel, C.; Revol, F.; Kitegi, C.

    2010-01-01

    For an in-vacuum undulator operated at small gaps the permanent magnet material needs to be highly resistant to possible electron beam exposure. At room temperature, one generally uses Sm 2 Co 17 or high coercivity NdFeB magnets at the expense of a limited field performance. In a cryogenic permanent magnet undulator (CPMU), at a temperature of around 150 K, any NdFeB grade reveals a coercivity large enough to be radiation resistant. In particular, very high remanence NdFeB material can be used to build undulators with enhanced field and X-ray brilliance at high photon energy provided that the pre-baking of the undulator above 100 deg. C can be eliminated. The ESRF has developed a full scale 2 m long CPMU with a period of 18 mm. This prototype has been in operation on the ID6 test beamline since January 2008. A significant effort was put into the characterization of NdFeB material at low temperature, the development of dedicated magnetic measurement systems and cooling methods. The measured heat budget with beam is found to be larger than expected without compromising the smooth operation of the device. Leading on from this first experience, new CPMUs are currently being considered for the upgrade of the ESRF.

  3. CEBAF cryogenic system design

    International Nuclear Information System (INIS)

    Rode, C.; Brindza, P.

    1986-01-01

    The Continuous Electron Beam Accelerator Facility (CEBAF) is a standing wave superconducting linear accelerator with a maximum energy of 4 GeV and 200 μA beam current. The 418 Cornell/CEBAF superconducting niobium accelerating cavities are arranged in two 0.5 GeV linacs with magnetic recirculating arcs at each end. There is one recirculating arc for each energy beam that is circulating and any three of the four correlated energies may be supplied to any of the three experimental halls. The cryogenics system for CEBAF consists of a 5kW central helium refrigerator and a transfer line system to supply 2.2 K 2.8 ATM helium to the cavity cryostats, 40 K helium at 3.5 ATM to the radiation shields and 4.5K helium at 2.8 ATM to the superconducting magnetic spectrometers in the experimental halls. Both the 2.2K and the 4.5K helium are expanded by Joule-Thompson (JT) valves in the individual cryostats yielding 2.0K at .031 ATM and 4.4K at 1.2 ATM respectively. The Central Helium Refrigerator is located in the center of the CEBAF racetrack with the transfer lines located in the linac tunnels

  4. Analog and hybrid computing

    CERN Document Server

    Hyndman, D E

    2013-01-01

    Analog and Hybrid Computing focuses on the operations of analog and hybrid computers. The book first outlines the history of computing devices that influenced the creation of analog and digital computers. The types of problems to be solved on computers, computing systems, and digital computers are discussed. The text looks at the theory and operation of electronic analog computers, including linear and non-linear computing units and use of analog computers as operational amplifiers. The monograph examines the preparation of problems to be deciphered on computers. Flow diagrams, methods of ampl

  5. Structured Analog CMOS Design

    CERN Document Server

    Stefanovic, Danica

    2008-01-01

    Structured Analog CMOS Design describes a structured analog design approach that makes it possible to simplify complex analog design problems and develop a design strategy that can be used for the design of large number of analog cells. It intentionally avoids treating the analog design as a mathematical problem, developing a design procedure based on the understanding of device physics and approximations that give insight into parameter interdependences. The proposed transistor-level design procedure is based on the EKV modeling approach and relies on the device inversion level as a fundament

  6. A cryogenic slab CO laser

    International Nuclear Information System (INIS)

    Ionin, Andrei A; Kozlov, A Yu; Seleznev, L V; Sinitsyn, D V

    2009-01-01

    A compact capacitive transverse RF-discharge-pumped slab CO laser with cryogenically cooled electrodes, which operates both in the cw and repetitively pulsed regimes, is fabricated. The laser operation is studied in the free running multifrequency regime at the vibrational - rotational transitions of the fundamental (V + 1 → V) vibrational bands of the CO molecule in the spectral region from 5.1 to 5.4 μm. Optimal operation conditions (gas mixture composition and pressure, RF pump parameters) are determined. It is shown that only gas mixtures with a high content of oxygen (up to 20% with respect to the concentration of CO molecules) can be used as an active medium of this laser. It is demonstrated that repetitively pulsed pumping is more efficient compared to cw pumping. In this case, quasi-cw lasing regime can be obtained. The maximum average output power of ∼12 W was obtained for this laser operating on fundamental bands and its efficiency achieved ∼14 %. The frequency-selective operation regime of the slab RF-discharge-pumped CO laser was realised at ∼ 100 laser lines in the spectral region from 5.0 to 6.5 μm with the average output power of up to several tens of milliwatts in each line. Lasing at the transitions of the first vibrational overtone (V + 2 → V) of the CO molecule is obtained in the spectral region from 2.5 to 3.9 μm. The average output power of the overtone laser achieved 0.3 W. All the results were obtained without the forced gas mixture exchange in the discharge chamber. Under fixed experimental conditions, repetitively pulsed lasing (with fluctuations of the output characteristics no more than ±10 %) was stable for more than an hour. (lasers)

  7. Electric breakdown of high polymer insulating materials at cryogenic temperature

    International Nuclear Information System (INIS)

    Kim, Sanhyon; Yoshino, Katsumi

    1985-01-01

    Cryogenic properties : temperature dependence of E sub(b) and effects of media upon E sub(b) were investigated on several high polymers. Temperature conditions were provided by liquid He (4.2 K), liquid N 2 (77 K) and cryogen (dry ice-methyl alcohol, 194 K). Silicone oil was used also at ambient temperature and elevated temperature. Polymer film coated with gold by vacuum evaporation was placed in cryostat, and high tension from pulse generator was applied to the film. Dielectric breakdowns were detected by oscilloscope and observed visually. The results of experiment are summerized as follow. (1) E sub(b) of film in He is affected by medium remarkably, and covering with 3-methyl pentane is effective for increasing E sub(b). (2) Temperature dependence of E sub(b) was not recognized in cryogenic temperature below liquid N 2 . (3) Temperature characteristic of E sub(b) changes considerably at the critical temperature T sub(c), and T sub(c) is dependent on material. (4) Strength against dielectric breakdown under cryogenic temperature is not affected by bridging caused by irradiation of electron beam. (5) Dielectric breakdown is thought to be caused by electronic process such as electron avalanche. Consequently, for designing insulation for the temperature below liquid He, insulation design for liquid N 2 is thought to be sufficient. However, the degradation and breakdown by mechanical stress under cryogenic temperature must be taken into consideration. (Ishimitsu, A.)

  8. Cryogenics bringing the temperature down, underground

    CERN Multimedia

    2005-01-01

    The first 600m of the LHC cryogenic distribution line (QRL), which will feed the accelerator's superconducting magnets, has passed initial validating tests of its mechanical design at room and cryogenic temperatures.

  9. Safety experiences in using cryogenic liquid in IGCAR

    International Nuclear Information System (INIS)

    Senthilkumar, B.; Singh, Dharmendra S.; Kandasamy, S.

    2009-01-01

    Indira Gandhi Centre for Atomic Research is engaged in large-scale development work in the field of Fast Reactor Technology associated fuel cycle facilities metallurgy and material science. To meet the growing demands of these activities, the cryogenic are manufactured, stored, and handled in the Centre. Lot of precautionary measures are taken during the plant operations. However, the safety of the men and machine can be ensured only by systematic safety studies. So this study was taken up to identify the hazards of cryogenic, unsafe acts/unsafe conditions and to improve the safety standards in the Centre

  10. Materials for cold neutron sources: Cryogenic and irradiation effects

    International Nuclear Information System (INIS)

    Alexander, D.J.

    1990-01-01

    Materials for the construction of cold neutron sources must satisfy a range of demands. The cryogenic temperature and irradiation create a severe environment. Candidate materials are identified and existing cold sources are briefly surveyed to determine which materials may be used. Aluminum- and magnesium-based alloys are the preferred materials. Existing data for the effects of cryogenic temperature and near-ambient irradiation on the mechanical properties of these alloys are briefly reviewed, and the very limited information on the effects of cryogenic irradiation are outlined. Generating mechanical property data under cold source operating conditions is a daunting prospect. It is clear that the cold source material will be degraded by neutron irradiation, and so the cold source must be designed as a brittle vessel. The continued effective operation of many different cold sources at a number of reactors makes it clear that this can be accomplished. 46 refs., 8 figs., 2 tab

  11. Development of cryogenic installations for large liquid argon neutrino detectors

    CERN Document Server

    Adamowski, M; Geynisman, M; Hentschel, S; Montanari, D; Nessi, M; Norris, B

    2015-01-01

    A proposal for a very large liquid argon (68,000 kg) based neutrino detector is being studied. To validate the design principles and the detector technology, and to gain experience in the development of the cryostats and the cryogenic systems needed for such large experiments, several smaller scale installations will be developed and implemented, at Fermilab and CERN. The cryogenic systems for these installations will be developed, constructed, installed and commissioned by an international engineering team. These installations shall bring the required cooling power under specific conditions to the experiments for the initial cool-down and the long term operation, and shall also guarantee the correct distribution of the cooling power within the cryostats to ensure a homogeneous temperature distribution within the cryostat itself. The cryogenic systems shall also include gaseous and liquid phase argon purification devices to be used to reach and maintain the very stringent purity requirements needed for these...

  12. Cryogenic system for the HERA magnet measurement facility

    International Nuclear Information System (INIS)

    Barton, H.R. Jr.; Clausen, M.; Kebler, G.

    1986-01-01

    This paper describes the design for a helium, cryogenic distribution system that allows independent operation and testing of superconducting magnets of the HERA project before they are installed in the 6-km ring tunnel. The 820-GeV proton storage ring of HERA will contain approximately 650 magnets having superconducting coils which are clamped by aluminum/stainless-steel collars and surrounded by a yoke of magnetic iron at liquid helium temperature. When the magnets arive at DESY from the manufacture, each magnet will be individually tested at helium operating conditions in the magnet measurement facility to insure the quality of the magnetic characteristics and the cryogenic performance. The capabilities of the cryogenic system and the schedule for magnet testing are discussed

  13. Performance evaluation of various cryogenic energy storage systems

    International Nuclear Information System (INIS)

    Abdo, Rodrigo F.; Pedro, Hugo T.C.; Koury, Ricardo N.N.; Machado, Luiz; Coimbra, Carlos F.M.; Porto, Matheus P.

    2015-01-01

    This work compares various CES (cryogenic energy storage) systems as possible candidates to store energy from renewable sources. Mitigating solar and wind power variability and its direct effect on local grid stability are already a substantial technological bottleneck for increasing market penetration of these technologies. In this context, CES systems represent low-cost solutions for variability that can be used to set critical power ramp rates. We investigate the different thermodynamic and engineering constraints that affect the design of CES systems, presenting theoretical simulations, indicating that optimization is also needed to improve the cryogenic plant performance. - Highlights: • We assessed the performance of cryogenic energy storage systems. • We re-evaluated the Linde–Hampson cycle proposed by Chen. • We proposed the Claude and Collins cycles as alternatives for the Linde–Hampson cycle. • We concluded that Claude cycle is the best alternative for the simulated conditions.

  14. Cryogenic safety organisation at CERN

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    With Safety being a top priority of CERN’s general policy, the Organisation defines and implements a Policy that sets out the general principles governing Safety at CERN. To the end of the attainment of said Safety objectives, the organic units (owners/users of the equipment) are assigned the responsibility for the implementation of the CERN Safety Policy at all levels of the organization, whereas the Health and Safety and Environmental Protection Unit (HSE) has the role of providing assistance for the implementation of the Safety Policy, and a monitoring role related to the implementation of continuous improvement of Safety, compliance with the Safety Rules and the handling of emergency situations. This talk will elaborate on the roles, responsibilities and organisational structure of the different stakeholders within the Organization with regards to Safety, and in particular to cryogenic safety. The roles of actors of particular importance such as the Cryogenic Safety Officers (CSOs) and the Cryogenic Sa...

  15. Thermodynamic properties of cryogenic fluids

    CERN Document Server

    Leachman, Jacob; Lemmon, Eric; Penoncello, Steven

    2017-01-01

    This update to a classic reference text provides practising engineers and scientists with accurate thermophysical property data for cryogenic fluids. The equations for fifteen important cryogenic fluids are presented in a basic format, accompanied by pressure-enthalpy and temperature-entropy charts and tables of thermodynamic properties. It begins with a chapter introducing the thermodynamic relations and functional forms for equations of state, and goes on to describe the requirements for thermodynamic property formulations, needed for the complete definition of the thermodynamic properties of a fluid. The core of the book comprises extensive data tables and charts for the most commonly-encountered cryogenic fluids. This new edition sees significant updates to the data presented for air, argon, carbon monoxide, deuterium, ethane, helium, hydrogen, krypton, nitrogen and xenon. The book supports and complements NIST’s REFPROP - an interactive database and tool for the calculation of thermodynamic propertie...

  16. New Scanning Electron Microscope Used for Cryogenic Tensile Testing

    CERN Multimedia

    Maximilien Brice

    2013-01-01

    At CERN engineering department's installation for cryogenic tensile testing, the new scanning electron microscope (SEM) allows for detailed optical observations to be carried out. Using the SEM, surface coatings and tensile properties of materials can investigated in order to better understand how they behave under different conditions.

  17. Coupled Cryogenic Thermal and Electrical Models for Transient Analysis of Superconducting Power Devices with Integrated Cryogenic Systems

    Science.gov (United States)

    Satyanarayana, S.; Indrakanti, S.; Kim, J.; Kim, C.; Pamidi, S.

    2017-12-01

    Benefits of an integrated high temperature superconducting (HTS) power system and the associated cryogenic systems on board an electric ship or aircraft are discussed. A versatile modelling methodology developed to assess the cryogenic thermal behavior of the integrated system with multiple HTS devices and the various potential configurations are introduced. The utility and effectiveness of the developed modelling methodology is demonstrated using a case study involving a hypothetical system including an HTS propulsion motor, an HTS generator and an HTS power cable cooled by an integrated cryogenic helium circulation system. Using the methodology, multiple configurations are studied. The required total cooling power and the ability to maintain each HTS device at the required operating temperatures are considered for each configuration and the trade-offs are discussed for each configuration. Transient analysis of temperature evolution in the cryogenic helium circulation loop in case of a system failure is carried out to arrive at the required critical response time. The analysis was also performed for a similar liquid nitrogen circulation for an isobaric condition and the cooling capacity ratio is used to compare the relative merits of the two cryogens.

  18. Detecting analogies unconsciously

    Directory of Open Access Journals (Sweden)

    Thomas Peter Reber

    2014-01-01

    Full Text Available Analogies may arise from the conscious detection of similarities between a present and a past situation. In this functional magnetic resonance imaging study, we tested whether young volunteers would detect analogies unconsciously between a current supraliminal (visible and a past subliminal (invisible situation. The subliminal encoding of the past situation precludes awareness of analogy detection in the current situation. First, participants encoded subliminal pairs of unrelated words in either one or nine encoding trials. Later, they judged the semantic fit of supraliminally presented new words that either retained a previously encoded semantic relation (‘analog’ or not (‘broken analog’. Words in analogs versus broken analogs were judged closer semantically, which reflects unconscious analogy detection. Hippocampal activity associated with subliminal encoding correlated with the behavioral measure of unconscious analogy detection. Analogs versus broken analogs were processed with reduced prefrontal but enhanced medial temporal activity. We conclude that analogous episodes can be detected even unconsciously drawing on the episodic memory network.

  19. High efficiency, variable geometry, centrifugal cryogenic pump

    International Nuclear Information System (INIS)

    Forsha, M.D.; Nichols, K.E.; Beale, C.A.

    1994-01-01

    A centrifugal cryogenic pump has been developed which has a basic design that is rugged and reliable with variable speed and variable geometry features that achieve high pump efficiency over a wide range of head-flow conditions. The pump uses a sealless design and rolling element bearings to achieve high reliability and the ruggedness to withstand liquid-vapor slugging. The pump can meet a wide range of variable head, off-design flow requirements and maintain design point efficiency by adjusting the pump speed. The pump also has features that allow the impeller and diffuser blade heights to be adjusted. The adjustable height blades were intended to enhance the pump efficiency when it is operating at constant head, off-design flow rates. For small pumps, the adjustable height blades are not recommended. For larger pumps, they could provide off-design efficiency improvements. This pump was developed for supercritical helium service, but the design is well suited to any cryogenic application where high efficiency is required over a wide range of head-flow conditions

  20. A cryogenic DAC operating down to 4.2 K

    Science.gov (United States)

    Rahman, M. T.; Lehmann, T.

    2016-04-01

    This paper presents a 10 bit CMOS current steering digital to analog converter (DAC) that operates from room temperature to as low as 4.2 K. It works as the core part of a cryogenic Silicon quantum computer controller circuit producing rapid control gate voltage pulses for quantum bits (qubits) initialization. An improved analog calibration method with a unique unit current cell design is included in the D/A converter structure to overcome the extended cryogenic nonlinear and mismatch effects. The DAC retains its 10 bit linear monotonic behavior over the wide temperature range and it drives a 50 Ω load to 516 mV with a full scale rise time of 10 ns. The differential non-linearity (DNL) of the converter is 0.35LSB while its average power consumption is 32.18 mW from a 3 V power supply. The complete converter is fabricated using a commercial 0.5 μm 1 poly 3 metal Silicon on Sapphire (SOS) CMOS process. He briefly worked as a Lecturer in the Stamford University Bangladesh prior to starting his Ph.D. in 2012 in the School of Electrical Engineering and Telecommunications, UNSW. His Ph.D. research is focused on cryogenic electronics for Quantum Computer Interface. His main research interests are in designing data converters for ultra-low temperature electronics and biomedical applications. He spent two years as a Research Fellow at the University of Edinburgh, U.K., where he worked with biologically inspired artificial neural systems. From 1997 to 2000, he was an Assistant Professor in electronics at the Technical University of Denmark, working with low-power low-noise low-voltage analog and mixed analog-digital integrated circuits. From 2001 to 2003 he was Principal Engineer with Cochlear Ltd., Australia, where he was involved in the design of the world's first fully implantable cochlear implant. Today he is Associate Professor in microelectronics at the University of New South Wales, Australia. He has authored over 100 journal papers, conference papers, book chapters

  1. Analog circuit design

    CERN Document Server

    Dobkin, Bob

    2012-01-01

    Analog circuit and system design today is more essential than ever before. With the growth of digital systems, wireless communications, complex industrial and automotive systems, designers are being challenged to develop sophisticated analog solutions. This comprehensive source book of circuit design solutions aids engineers with elegant and practical design techniques that focus on common analog challenges. The book's in-depth application examples provide insight into circuit design and application solutions that you can apply in today's demanding designs. <

  2. Analog synthetic biology.

    Science.gov (United States)

    Sarpeshkar, R

    2014-03-28

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog-digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA-protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations.

  3. Heat switch technology for cryogenic thermal management

    Science.gov (United States)

    Shu, Q. S.; Demko, J. A.; E Fesmire, J.

    2017-12-01

    Systematic review is given of development of novel heat switches at cryogenic temperatures that alternatively provide high thermal connection or ideal thermal isolation to the cold mass. These cryogenic heat switches are widely applied in a variety of unique superconducting systems and critical space applications. The following types of heat switch devices are discussed: 1) magnetic levitation suspension, 2) shape memory alloys, 3) differential thermal expansion, 4) helium or hydrogen gap-gap, 5) superconducting, 6) piezoelectric, 7) cryogenic diode, 8) magneto-resistive, and 9) mechanical demountable connections. Advantages and limitations of different cryogenic heat switches are examined along with the outlook for future thermal management solutions in materials and cryogenic designs.

  4. Superconducting magnets and cryogenics: proceedings

    International Nuclear Information System (INIS)

    Dahl, P.F.

    1986-01-01

    Separate abstracts were prepared for 70 papers in these workshop proceeedings. Topics covered include: superconducting accelerator magnet research and development; superconductor development; electrical measurements; magnet design and construction methods; field correction methods; power schemes and quench protection; cryogenic systems; and magnet measurements

  5. Operation of large cryogenic systems

    International Nuclear Information System (INIS)

    Rode, C.H.; Ferry, B.; Fowler, W.B.; Makara, J.; Peterson, T.; Theilacker, J.; Walker, R.

    1985-06-01

    This report is based on the past 12 years of experiments on R and D and operation of the 27 kW Fermilab Tevatron Cryogenic System. In general the comments are applicable for all helium plants larger than 1000W (400 l/hr) and non mass-produced nitrogen plants larger than 50 tons per day. 14 refs., 3 figs., 1 tab

  6. Radiation hard cryogenic silicon detectors

    International Nuclear Information System (INIS)

    Casagrande, L.; Abreu, M.C.; Bell, W.H.; Berglund, P.; Boer, W. de; Borchi, E.; Borer, K.; Bruzzi, M.; Buontempo, S.; Chapuy, S.; Cindro, V.; Collins, P.; D'Ambrosio, N.; Da Via, C.; Devine, S.; Dezillie, B.; Dimcovski, Z.; Eremin, V.; Esposito, A.; Granata, V.; Grigoriev, E.; Hauler, F.; Heijne, E.; Heising, S.; Janos, S.; Jungermann, L.; Konorov, I.; Li, Z.; Lourenco, C.; Mikuz, M.; Niinikoski, T.O.; O'Shea, V.; Pagano, S.; Palmieuri, V.G.; Paul, S.; Pirollo, S.; Pretzl, K.; Rato, P.; Ruggiero, G.; Smith, K.; Sonderegger, P.; Sousa, P.; Verbitskaya, E.; Watts, S.; Zavrtanik, M.

    2002-01-01

    It has been recently observed that heavily irradiated silicon detectors, no longer functional at room temperature, 'resuscitate' when operated at temperatures below 130 K. This is often referred to as the 'Lazarus effect'. The results presented here show that cryogenic operation represents a new and reliable solution to the problem of radiation tolerance of silicon detectors

  7. LHC Cryogenics on the mend

    CERN Multimedia

    2004-01-01

    On 29 September, repairs began on the LHC cryogenic distribution line, or QRL, to replace a faulty part that occurs in the hundreds of elements of the line that are already on-site. The Accelerator Technology Department is designing a work programme to finish the repairs as soon as possible and minimize delays to the rest of the LHC project.

  8. Champagne for the cryogenics teams

    CERN Multimedia

    2005-01-01

    Christmas has come early for the LHC as a complete sector of the cryogenic distribution line has been operating at 10 degrees Kelvin (-263°C) for the past two weeks, just a few degrees above the machine's nominal operating temperature.

  9. Cryogenic detectors for particle physics

    International Nuclear Information System (INIS)

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

    1988-11-01

    A comprehensive introduction to cryogenic detector developments for particle physics is presented, covering conventional detectors cooled to low temperature (scintillators and semiconductors), superconductive and thermal sensitive devices, as well as the basics of cold electronics. After giving a critical overview of current work, we elaborate on possible new ways for further improvements and briefly evaluate the feasibility of the main proposed applications

  10. Formation of Fe/mg Smectite Under Acidic Conditions from Synthetic Adirondack Basaltic Glass: an Analog to Fe/mg Smectite Formation on Mars

    Science.gov (United States)

    Sutter, B.; Peretyazhko, T.; Morris, R. V.; Ming, D. W.

    2014-01-01

    Smectite has been detected as layered material hundreds of meters thick, in intracrater depositional fans, in plains sediments, and deposits at depth on Mars. If early Mars hosted a dense CO2 atmosphere, then extensive carbonate should have formed in the neutral/alkaline conditions expected for smectite formation. However, large carbonate deposits on Mars have not been discovered. Instead of neutral to moderately alkaline conditions, early Mars may have experienced mildly acidic conditions that allowed for Fe/Mg smectite formation but prevented widespread carbonate formation. The objective of this work is to demonstrate that Fe(II)/Mg saponite and nontronite can form in mildly acidic solutions (e.g., pH 4). Synthetic basaltic glass (Smectite was confirmed as the phyllosilicate after treatments with glycerol and KCl and heating to 550 C. Trioctahedral saponite was confirmed by the presence of a 4.58 to 4.63 Angstroms (02l) and 1.54Angstroms (060) peaks. Saponite concentration was highest, as indicated by XRD peak intensity, in the 10 mM Mg treatment followed by the 0 mM and then 10 mM Fe(II) treatments. This order of sapontite concentration suggests that Fe(II) additions may have a role in slowing the kinetics of saponite formation relative to the other treatments. Nontronite synthesis was attempted by exposing Adirondack basaltic glass to pH 4 oxic solutions (without N2 purge) at 200 C for 14 days. X-ray diffraction analysis indicated that mixtures of trioctahedral (saponite) and dioctahedral (nontronite) may have formed in these experiments based on the 02l and 060 peaks. Moessbauer analysis coupled with future experiments are planned to verify if nontronite can be formed under mildly acidic and oxic conditions. Results of this work demonstrate that acidic conditions could have occurred on an early Mars, which allowed for smectite formation but inhibited carbonate formation.

  11. Cryogenic readout techniques for germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Benato, G. [University of Zurich, (Switzerland); Cattadori, C. [INFN - Milano Bicocca, (Italy); Di Vacri, A. [INFN LNGS, (Italy); Ferri, E. [Universita Milano Bicocca/INFN Milano Bicocca, (Italy); D' Andrea, V.; Macolino, C. [GSSI/INFN LNGS, (Italy); Riboldi, S. [Universita degli Studi di Milano/INFN Milano, (Italy); Salamida, F. [Universita Milano Bicocca/INFN Milano Bicocca, (Italy)

    2015-07-01

    High Purity Germanium detectors are used in many applications, from nuclear and astro-particle physics, to homeland security or environment protection. Although quite standard configurations are often used, with cryostats, charge sensitive amplifiers and analog or digital acquisition systems all commercially available, it might be the case that a few specific applications, e.g. satellites, portable devices, cryogenic physics experiments, etc. also require the development of a few additional or complementary techniques. An interesting case is for sure GERDA, the Germanium Detector Array experiment, searching for neutrino-less double beta decay of {sup 76}Ge at the Gran Sasso National Laboratory of INFN - Italy. In GERDA the entire detector array, composed of semi-coaxial and BEGe naked crystals, is operated suspended inside a cryostat filled with liquid argon, that acts not only as cooling medium and but also as an active shield, thanks to its scintillation properties. These peculiar circumstances, together with the additional requirement of a very low radioactive background from all the materials adjacent to the detectors, clearly introduce significant constraints on the design of the Ge front-end readout electronics. All the Ge readout solutions developed within the framework of the GERDA collaboration, for both Phase I and Phase II, will be briefly reviewed, with their relative strength and weakness compared together and with respect to ideal Ge readout. Finally, the digital processing techniques developed by the GERDA collaboration for energy estimation of Ge detector signals will be recalled. (authors)

  12. Challenges in Using Analogies

    Science.gov (United States)

    Lin, Shih-Yin; Singh, Chandralekha

    2011-01-01

    Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features. One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same…

  13. Hydraulic Capacitor Analogy

    Science.gov (United States)

    Baser, Mustafa

    2007-01-01

    Students have difficulties in physics because of the abstract nature of concepts and principles. One of the effective methods for overcoming students' difficulties is the use of analogies to visualize abstract concepts to promote conceptual understanding. According to Iding, analogies are consistent with the tenets of constructivist learning…

  14. Multiresponse optimization of cryogenic drilling on Ti-6Al-4V alloy using topsis method

    International Nuclear Information System (INIS)

    Ahmed, L. Shakeel; Kumar, M. Pradeep

    2016-01-01

    Multiresponse optimization of process parameters in drilling is focused in this article using the TOPSIS technique to obtain minimum cutting temperature (T), thrust force (Ft), torque (Mt) and surface roughness (Ra), Circularity (Cir), Cylindricity (Cyl). The experiments were performed on Titanium alloy Ti-6Al-4V in different cooling environments: Wet cooling and cryogenic cooling conditions. Liquid nitrogen (LN 2 ) as a coolant is used in cryogenic machining. The control factors selected were machining environments, cutting speed (Vc) and feed rate (f). Eighteen experiments were conducted in wet and cryogenic LN2 conditions based on L 1 8 orthogonal array, respectively. The optimization results indicate drilling at V c = 40 m/min and f = 0.02 mm/rev which is of the lowest value in cryogenic LN 2 condition. A better performance is achieved too. The optimum multiresponses show that TOPSIS method is the most effective performance in the drilling process

  15. Cryogenic Hydrogen Fuel for Controlled Inertial Confinement Fusion (Cryogenic Target Factory Concept Based on FST-Layering Method)

    Science.gov (United States)

    Aleksandrova, I. V.; Koresheva, E. R.; Koshelev, I. E.; Krokhin, O. N.; Nikitenko, A. I.; Osipov, I. E.

    2017-12-01

    A central element of a power plant based on inertial confinement fusion (ICF) is a target with cryogenic hydrogen fuel that should be delivered to the center of a reactor chamber with a high accuracy and repetition rate. Therefore, a cryogenic target factory (CTF) is an integral part of any ICF reactor. A promising way to solve this problem consists in the FST layering method developed at the Lebedev Physical Institute (LPI). This method (rapid fuel layering inside moving free-standing targets) is unique, having no analogs in the world. The further development of FST-layering technologies is implemented in the scope of the LPI program for the creation of a modular CTF and commercialization of the obtained results. In this report, we discuss our concept of CTF (CTF-LPI) that exhibits the following distinctive features: using a FST-layering technology for the elaboration of an in-line production of cryogenic targets, using an effect of quantum levitation of high-temperature superconductors (HTSCs) in magnetic field for noncontacting manipulation, transport, and positioning of the free-standing cryogenic targets, as well as in using a Fourier holography technique for an on-line characterization and tracking of the targets flying into the reactor chamber. The results of original experimental and theoretical investigations performed at LPI indicate that the existing and developing target fabrication capabilities and technologies can be applied to ICF target production. The unique scientific, engineering, and technological base developed in Russia at LPI allows one to make a CTFLPI prototype for mass production of targets and delivery thereof at the required velocity into the ICF reactor chamber.

  16. Cryogenic systems for detectors and particle accelerators

    International Nuclear Information System (INIS)

    Sondericker, J.H.

    1988-01-01

    It's been one hundred years since the first successful experiments were carried out leading to the liquefaction of oxygen which birthed the field of cryogenics and about sixty years since cryogenics went commercial. Originally, cryogenics referred to the technology and art of producing low temperatures but today the definition adopted by the XII Congress of the International Institute of Refrigeration describes cryogenics as the study of phenomena, techniques, and concepts occurring at our pertaining to temperatures below 120 K. Modern acceptance of the importance and use of cryogenic fluids continues to grow. By far, the bulk of cryogenic products are utilized by industry for metal making, agriculture, medicine, food processing and as efficient storage of fuels. Cryogenics has found many uses in the scientific community as well, enabling the development of ultra low noise amplifiers, fast cold electronics, cryopumped ultra high vacuums, the production of intense magnetic fields and low loss power transmission through the sue of cryogenically cooled superconductors. High energy physic research has been and continues to use cryogenic hardware to produce liquids used as detector targets and to produce refrigeration necessary to cool superconducting magnets to design temperature for particle accelerator applications. In fact, today's super accelerators achieve energies that would be impossible to reach with conventional copper magnets, demonstrating that cryogenics has become an indispensable ingredient in today's scientific endeavors

  17. Meat analog: a review.

    Science.gov (United States)

    Malav, O P; Talukder, S; Gokulakrishnan, P; Chand, S

    2015-01-01

    The health-conscious consumers are in search of nutritious and convenient food item which can be best suited in their busy life. The vegetarianism is the key for the search of such food which resembles the meat in respect of nutrition and sensory characters, but not of animal origin and contains vegetable or its modified form, this is the point when meat analog evolved out and gets shape. The consumers gets full satisfaction by consumption of meat analog due to its typical meaty texture, appearance and the flavor which are being imparted during the skilled production of meat analog. The supplement of protein in vegetarian diet through meat alike food can be fulfilled by incorporating protein-rich vegetative food grade materials in meat analog and by adopting proper technological process which can promote the proper fabrication of meat analog with acceptable meat like texture, appearance, flavor, etc. The easily available vegetables, cereals, and pulses in India have great advantages and prospects to be used in food products and it can improve the nutritional and functional characters of the food items. The various form and functional characters of food items are available world over and attracts the meat technologists and the food processors to bring some innovativeness in meat analog and its presentation and marketability so that the acceptability of meat analog can be overgrown by the consumers.

  18. SURFACE ROUGHNESS AND CUTTING FORCES IN CRYOGENIC TURNING OF CARBON STEEL

    Directory of Open Access Journals (Sweden)

    T. C. YAP

    2015-07-01

    Full Text Available The effect of cryogenic liquid nitrogen on surface roughness, cutting forces, and friction coefficient of the machined surface when machining of carbon steel S45C in wet, dry and cryogenic condition was studied through experiments. The experimental results show that machining with liquid nitrogen increases the cutting forces, reduces the friction coefficient, and improves the chips produced. Beside this, conventional machining with cutting fluid is still the most suitable method to produce good surface in high speed machining of carbon steel S45C whereas dry machining produced best surface roughness in low speed machining. Cryogenic machining is not able to replace conventional cutting fluid in turning carbon steel.

  19. Results of radiation tests at cryogenic temperature on some selected organic materials for the LHC

    International Nuclear Information System (INIS)

    Tavlet, M.; Schoenbacher, H.

    1999-01-01

    In the near future, particle accelerators and detectors as well as fusion reactors will operate at cryogenic temperatures. At temperatures as low as 2 K, the organic materials used for the insulation of the superconducting magnets and cables will be exposed to high radiation levels. In this work, a representative selection of organic materials comprising insulating films, cable insulations and epoxy-type-impregnated resins were exposed to neutron and gamma radiation of nuclear reactors, both at ambient and cryogenic temperatures, and were subsequently mechanically tested. The results show that the radiation degradation is never worse in a cryogenic fluid than it is in usual ambient conditions. (author)

  20. Students' Pre- and Post-Teaching Analogical Reasoning when They Draw Their Analogies

    Science.gov (United States)

    Mozzer, Nilmara Braga; Justi, Rosaria

    2012-01-01

    Analogies are parts of human thought. From them, we can acquire new knowledge or change that which already exists in our cognitive structure. In this sense, understanding the analogical reasoning process becomes an essential condition to understand how we learn. Despite the importance of such an understanding, there is no general agreement in…

  1. Troubleshooting analog circuits

    CERN Document Server

    Pease, Robert A

    1991-01-01

    Troubleshooting Analog Circuits is a guidebook for solving product or process related problems in analog circuits. The book also provides advice in selecting equipment, preventing problems, and general tips. The coverage of the book includes the philosophy of troubleshooting; the modes of failure of various components; and preventive measures. The text also deals with the active components of analog circuits, including diodes and rectifiers, optically coupled devices, solar cells, and batteries. The book will be of great use to both students and practitioners of electronics engineering. Other

  2. Electromagnetic dampers for cryogenic applications

    Science.gov (United States)

    Brown, Gerald V.; Dirusso, Eliseo

    1988-01-01

    Cryogenic turbomachinery of the type used to pump high-pressure liquid hydrogen at -423 F and liquid oxygen at -297 F to the main engines of the Space Shuttle are subjected to lateral rotor vibrations from unbalance forces and transient loads. Conventional dampers which utilize viscous fluids such as lubricating oil cannot be used in turbopumps because the bearing components are filled with either liquid hydrogen or liquid oxygen, which have viscosity comparable to air and, therefore, are not effective in viscous dampers. Electromagentic dampers are currently being explored as a means of providing damping in cryogenic turbopumps because their damping effectiveness increases as temperature decreases and because they are compatible with the liquid hydrogen or liquid oxygen in the turbopumps.

  3. Testing of Prototype Magnetic Suspension Cryogenic Transfer Line

    Science.gov (United States)

    Fesmire, J. E.; Augustynowicz, S. D.; Nagy, Z. F.; Sojourner, S. J.; Shu, Q. S.; Cheng, G.; Susta, J. T.

    2006-04-01

    A 6-meter prototype cryogenic transfer line with magnetic suspension was tested for its mechanical and thermal performance at the Cryogenics Test Laboratory of NASA Kennedy Space Center (KSC). A test facility with two cryogenic end-boxes was designed and commissioned for the testing. Suspension mechanisms were verified through a series of tests with liquid nitrogen. The thermal performance of the prototype was determined using the new test apparatus. The tested prototype has incorporated temperature and vacuum pressure data acquisition ports, customized interfaces to cryogenic end-boxes, and instrumentation. All tests were conducted under simulated onsite transfer line working conditions. A static (boiloff rate measurement) testing method was employed to demonstrate the gross heat leak in the tested article. The real-time temperature distribution, vacuum level, levitation distance, and mass flow rate were measured. The main purpose of this paper is to summarize the testing facility design and preparation, test procedure, and primary test results. Special arrangements (such as turning on/off mechanical support units, observing levitation gap, and setting up the flowmeter) in testing of such a magnetically levitated transfer line are also discussed. Preliminary results show that the heat leak reduction of approximately one-third to one-half is achievable through such transfer lines with a magnetic suspension system.

  4. Cryogenic moderator simulations: confronting reality

    International Nuclear Information System (INIS)

    Iverson, E. B.

    1999-01-01

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a spallation neutron source dedicated to materials research. Its three cryogenic methane moderators provide twelve neutron beams to fourteen instruments and test facilities. This report concerns ongoing activities for benchmarking our Monte Carlo model of the IPNS neutron generation system. This paper concentrates on the techniques (both experimental and calculational) used in such benchmarking activities

  5. COOLING STAGES OF CRYOGENIC SYSTEMS

    OpenAIRE

    Троценко, А. В.

    2011-01-01

    The formalized definition for cooling stage of low temperature system is done. Based on existing information about the known cryogenic unit cycles the possible types of cooling stages are single out. From analyses of these stages their classification by various characteristics is suggested. The results of thermodynamic optimization of final throttle stage of cooling, which are used as working fluids helium, hydrogen and nitrogen, are shown.

  6. Composite materials for cryogenic structures

    International Nuclear Information System (INIS)

    Kasen, M.B.

    1978-01-01

    The paper is concerned with the composition, mechanical properties and capabilities of various types of composite materials for cryogenic structures. Attention is given to high-pressure plastic laminates, low-pressure plastic laminates, metal-matrix laminates, and aggregates (low-temperature concretes). The ability of these materials to match the strength and modulus of stainless steels suggests that their usage will substantially increase as alloying elements become scarce and more expensive

  7. Room temperature cryogenic test interface

    International Nuclear Information System (INIS)

    Faris, S. M.; Davidson, A.; Moskowitz, P. A.; Sai-Halasz, G. A.

    1985-01-01

    This interface permits the testing of high speed semiconductor devices (room-temperature chips) by a Josephson junction sampling device (cryogenic chip) without intolerable loss of resolution. The interface comprises a quartz pass-through plug which includes a planar transmission line interconnecting a first chip station, where the cryogenic chip is mounted, and a second chip station, where the semiconductor chip to be tested is temporarily mounted. The pass-through plug has a cemented long half-cylindrical portion and short half-cylindrical portion. The long portion carries the planar transmission line, the ends of which form the first and second chip mounting stations. The short portion completes the cylinder with the long portion for part of its length, where a seal can be achieved, but does not extend over the chip mounting stations. Sealing is by epoxy cement. The pass-through plug is sealed in place in a flange mounted to the chamber wall. The first chip station, with the cryogenic chip attached, extends into the liquid helium reservoir. The second chip station is in the room temperature environment required for semiconductor operation. Proper semiconductor operating temperature is achieved by a heater wire and control thermocouple in the vicinity of each other and the second chip mounting station. Thermal isolation is maintained by vacuum and seals. Connections for power and control, for test result signals, for temperature control and heating, and for vacuum complete the test apparatus

  8. Analog circuits cookbook

    CERN Document Server

    Hickman, Ian

    2013-01-01

    Analog Circuits Cookbook presents articles about advanced circuit techniques, components and concepts, useful IC for analog signal processing in the audio range, direct digital synthesis, and ingenious video op-amp. The book also includes articles about amplitude measurements on RF signals, linear optical imager, power supplies and devices, and RF circuits and techniques. Professionals and students of electrical engineering will find the book informative and useful.

  9. FGF growth factor analogs

    Science.gov (United States)

    Zamora, Paul O [Gaithersburg, MD; Pena, Louis A [Poquott, NY; Lin, Xinhua [Plainview, NY; Takahashi, Kazuyuki [Germantown, MD

    2012-07-24

    The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

  10. Characterizing Dissolved Gases in Cryogenic Liquid Fuels

    Science.gov (United States)

    Richardson, Ian A.

    Pressure-Density-Temperature-Composition (PrhoT-x) measurements of cryogenic fuel mixtures are a historical challenge due to the difficulties of maintaining cryogenic temperatures and precision isolation of a mixture sample. For decades NASA has used helium to pressurize liquid hydrogen propellant tanks to maintain tank pressure and reduce boil off. This process causes helium gas to dissolve into liquid hydrogen creating a cryogenic mixture with thermodynamic properties that vary from pure liquid hydrogen. This can lead to inefficiencies in fuel storage and instabilities in fluid flow. As NASA plans for longer missions to Mars and beyond, small inefficiencies such as dissolved helium in liquid propellant become significant. Traditional NASA models are unable to account for dissolved helium due to a lack of fundamental property measurements necessary for the development of a mixture Equation Of State (EOS). The first PrhoT-x measurements of helium-hydrogen mixtures using a retrofitted single-sinker densimeter, magnetic suspension microbalance, and calibrated gas chromatograph are presented in this research. These measurements were used to develop the first multi-phase EOS for helium-hydrogen mixtures which was implemented into NASA's Generalized Fluid System Simulation Program (GFSSP) to determine the significance of mixture non-idealities. It was revealed that having dissolved helium in the propellant does not have a significant effect on the tank pressurization rate but does affect the rate at which the propellant temperature rises. PrhoT-x measurements are conducted on methane-ethane mixtures with dissolved nitrogen gas to simulate the conditions of the hydrocarbon seas of Saturn's moon Titan. Titan is the only known celestial body in the solar system besides Earth with stable liquid seas accessible on the surface. The PrhoT-x measurements are used to develop solubility models to aid in the design of the Titan Submarine. NASA is currently designing the submarine

  11. The evolution of cryogenic safety at Fermilab

    International Nuclear Information System (INIS)

    Stanek, R.; Kilmer, J.

    1992-12-01

    Over the past twenty-five years, Fermilab has been involved in cryogenic technology as it relates to pursuing experimentation in high energy physics. The Laboratory has instituted a strong cryogenic safety program and has maintained a very positive safety record. The solid commitment of management and the cryogenic community to incorporating safety into the system life cycle has led to policies that set requirements and help establish consistency for the purchase and installation of equipment and the safety analysis and documentation

  12. The cryogenic control system of EAST

    International Nuclear Information System (INIS)

    Zhuang, M.; Hu, L.B.; Zhow, Z.W.; Xia, G.H.

    2012-01-01

    Highlights: ► A reliable and flexible duplex control system is required for cryogenic system. ► The cryogenic control system is based on Delta-V DCS. ► It has been proved to be an effective way to control cryogenic process. ► It will provide useful experience and inspiration for the development in the cryogenic control engineering. - Abstract: A large scale helium cryogenic system is one of the key components for the EAST tokamak device for the cooling of PF and TF coils, structures, thermal shields, buslines, current leads and cryopumps. Since the cooling scheme of the EAST cryogenic system is fairly complicated, a reliable and flexible control system is required for cryogenic system. The cryogenic control system is based on DeltaV DCS which is the process control software developed by Emerson Company. The EAST cryogenic system has been in operation for four years and has been proved to be safe, stable and energy saving by the past 7 experiments. This paper describes the redundant control network, hardware configuration, software structure, auxiliary system and the new development in the future.

  13. Electrical Circuits and Water Analogies

    Science.gov (United States)

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  14. CMOS analog circuit design

    CERN Document Server

    Allen, Phillip E

    1987-01-01

    This text presents the principles and techniques for designing analog circuits to be implemented in a CMOS technology. The level is appropriate for seniors and graduate students familiar with basic electronics, including biasing, modeling, circuit analysis, and some familiarity with frequency response. Students learn the methodology of analog integrated circuit design through a hierarchically-oriented approach to the subject that provides thorough background and practical guidance for designing CMOS analog circuits, including modeling, simulation, and testing. The authors' vast industrial experience and knowledge is reflected in the circuits, techniques, and principles presented. They even identify the many common pitfalls that lie in the path of the beginning designer--expert advice from veteran designers. The text mixes the academic and practical viewpoints in a treatment that is neither superficial nor overly detailed, providing the perfect balance.

  15. Scanning Quantum Cryogenic Atom Microscope

    Science.gov (United States)

    Yang, Fan; Kollár, Alicia J.; Taylor, Stephen F.; Turner, Richard W.; Lev, Benjamin L.

    2017-03-01

    Microscopic imaging of local magnetic fields provides a window into the organizing principles of complex and technologically relevant condensed-matter materials. However, a wide variety of intriguing strongly correlated and topologically nontrivial materials exhibit poorly understood phenomena outside the detection capability of state-of-the-art high-sensitivity high-resolution scanning probe magnetometers. We introduce a quantum-noise-limited scanning probe magnetometer that can operate from room-to-cryogenic temperatures with unprecedented dc-field sensitivity and micron-scale resolution. The Scanning Quantum Cryogenic Atom Microscope (SQCRAMscope) employs a magnetically levitated atomic Bose-Einstein condensate (BEC), thereby providing immunity to conductive and blackbody radiative heating. The SQCRAMscope has a field sensitivity of 1.4 nT per resolution-limited point (approximately 2 μ m ) or 6 nT /√{Hz } per point at its duty cycle. Compared to point-by-point sensors, the long length of the BEC provides a naturally parallel measurement, allowing one to measure nearly 100 points with an effective field sensitivity of 600 pT /√{Hz } for each point during the same time as a point-by-point scanner measures these points sequentially. Moreover, it has a noise floor of 300 pT and provides nearly 2 orders of magnitude improvement in magnetic flux sensitivity (down to 10-6 Φ0/√{Hz } ) over previous atomic probe magnetometers capable of scanning near samples. These capabilities are carefully benchmarked by imaging magnetic fields arising from microfabricated wire patterns in a system where samples may be scanned, cryogenically cooled, and easily exchanged. We anticipate the SQCRAMscope will provide charge-transport images at temperatures from room temperature to 4 K in unconventional superconductors and topologically nontrivial materials.

  16. Analogical Reasoning in Geometry Education

    Science.gov (United States)

    Magdas, Ioana

    2015-01-01

    The analogical reasoning isn't used only in mathematics but also in everyday life. In this article we approach the analogical reasoning in Geometry Education. The novelty of this article is a classification of geometrical analogies by reasoning type and their exemplification. Our classification includes: analogies for understanding and setting a…

  17. Digital and analog communication systems

    Science.gov (United States)

    Shanmugam, K. S.

    1979-01-01

    The book presents an introductory treatment of digital and analog communication systems with emphasis on digital systems. Attention is given to the following topics: systems and signal analysis, random signal theory, information and channel capacity, baseband data transmission, analog signal transmission, noise in analog communication systems, digital carrier modulation schemes, error control coding, and the digital transmission of analog signals.

  18. A Cryogenic Infrared Calibration Target

    Science.gov (United States)

    Wollack, E. J.; Kinzer, R. E., Jr.; Rinehart, S. A.

    2014-01-01

    A compact cryogenic calibration target is presented that has a peak diffuse reflectance, R target. The resulting target assembly is lightweight, has a low-geometric profile, and has survived repeated thermal cycling from room temperature to approx.4 K. Basic design considerations, governing equations, and test data for realizing the structure described are provided. The optical properties of selected absorptive materials-Acktar Fractal Black, Aeroglaze Z306, and Stycast 2850 FT epoxy loaded with stainless steel powder-are characterized and presented

  19. The Cryogenic Storage Ring CSR

    OpenAIRE

    von Hahn, Robert; Becker, Arno; Berg, Felix; Blaum, Klaus; Breitenfeldt, Christian; Fadil, Hisham; Fellenberger, Florian; Froese, Michael; George, Sebastian; Göck, Jürgen; Grieser, Manfred; Grussie, Florian; Guerin, Elisabeth A.; Heber, Oded; Herwig, Philipp

    2016-01-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion a...

  20. Cryogenic fluid management program flight concept definition

    Science.gov (United States)

    Kroeger, Erich

    1987-01-01

    The Lewis Research Center's cryogenic fluid management program flight concept definition is presented in viewgraph form. Diagrams are given of the cryogenic fluid management subpallet and its configuration with the Delta launch vehicle. Information is given in outline form on feasibility studies, requirements definition, and flight experiments design.

  1. Analogs for transuranic elements

    International Nuclear Information System (INIS)

    Weimer, W.C.; Laul, J.C.; Kutt, J.C.

    1981-01-01

    A combined theoretical and experimental approach is being used to estimate the long-term environmental and biogeochemical behaviors of selected transuranic elements. The objective of this research is to estimate the effect that long-term (hundreds of years) environmental weathering has on the behavior of the transuranic elements americium and curium. This is achieved by investigating the actual behavior of naturally occurring rare earth elements, especially neodymium, that serve as transuranic analogs. Determination of the analog element behavior provides data that can be used to estimate the ultimate availability to man of transuranic materials released into the environment

  2. Children's analogical reasoning about natural phenomena.

    Science.gov (United States)

    Pauen, S; Wilkening, F

    1997-10-01

    This report investigates children's analogical reasoning in a physics task, using an analogy generated by the children rather than by the experimenter. A total of 127 elementary school children took part in three related studies. Children learned to predict the behavior of a balance scale. Later, they were asked to solve a force interaction problem. Two versions of the balance scale training were devised: version A suggested an incorrect solution to the target problem (negative analogy), and version B suggested a correct solution to the target problem (positive analogy). In Study 1, 9- to 10-year-olds showed spontaneous transfer in both training conditions. In Study 2, 7-year-olds did not show any transfer in the positive analogy condition. Study 3 revealed that the lack of transfer in younger children was not due to a failure either to notice the analogy or to perform the mapping. Instead, 7-year-olds transferred only selected aspects of the correct solution. Copyright 1997 Academic Press.

  3. Thermographic Methods of Detecting Insulation Voids in Large Cryogenic Tanks

    Science.gov (United States)

    Arens, Ellen; Nurge, Mark; Youngquist, Robert; Starr, Stanley

    2010-01-01

    Four very large (900Kgal) cryogenic liquid hydrogen and oxygen storage tanks at Kennedy Space Center's LC-39 launch pads were constructed in 1965 to support the Apollo/Saturn V Program and continue to support the Space Shuttle Program. These double-walled spherical tanks with powdered insulation in the annular region, have received minimal refurbishment or even inspection over the years. Intrusively inspecting these tanks would mean a significant down time to the program as the cryogenic liquid and the perlite insulation would have to be removed which would be a significant task and long-term schedule disruption. A study of the tanks was performed to determine the extent to which performance and structural information could be revealed without intrusive inspection. Thermal images of the tanks were taken over a variety of environmental conditions to determine the best conditions under which to compare and use thermography as a health monitoring technique as the tanks continue to age. The settling and subsequent compaction of insulation is a serious concern for cryogenic tanks. Comparison of images from the tanks reveals significant variations in the insulation in the annual regions and point to the use of thermography as a way to monitor for insulation migration and possible compaction. These measurements, when combined with mathematical models of historical boil-off data provide key insight to the condition of the vessels. Acceptance testing methods for new tanks, before they are filled with cryogenic commodity (and thereby thermally cycled), are needed and we explore how thermography can be used to accomplish this.

  4. Control and operation cost optimization of the HISS cryogenic system

    International Nuclear Information System (INIS)

    Porter, J.; Anderson, D.; Bieser, F.

    1984-01-01

    This chapter describes a control strategy for the Heavy Ion Spectrometer System (HISS), which relies upon superconducting coils of cryostable design to provide a particle bending field of 3 tesla. The control strategy has allowed full time unattended operation and significant operating cost reductions. Microprocessor control of flash boiling style LIN circuits has been successful. It is determined that the overall operating cost of most cryogenic systems using closed loop helium systems can be minimized by properly balancing the total heat load between the helium and nitrogen circuits to take advantage of the non-linearity which exists in the power input to 4K refrigeration characteristic. Variable throughput compressors have the advantage of turndown capability at steady state. It is concluded that a hybrid system using digital and analog input for control, data display and alarms enables full time unattended operation

  5. Cryogenic laboratory (80 K - 4 K)

    International Nuclear Information System (INIS)

    Brad, Sebastian; Steflea, Dumitru

    2002-01-01

    condensing temperature (65 K). In the Joule-Thompson valve, the helium is expanded to 1.2 bar (corresponding to approx. 4.4 K). The resulting helium-liquid-mixture is transferred to the LHe container via a coaxial, vacuum-insulated transfer pipe. The He-cold-gas in the LHe container is transferred back to the low-pressure side of the heat exchanger E 205 to the cold-box via the transfer pipe. In the counter-flow to the cooling high-pressure flow the gas is now heated up to approx. 293 K in the heat exchangers. The gas leaving the cold-box at a pressure of approx. 1.07 bar is transferred to the suction side of the screw compressor together with the feed gas out of the helium reserve container via PC 111. To put into service the helium liquefier Type L5 tests were made to determine the performances and the cryogenic cycle efficiency: modified and complete components and spare parts, in order to adapted to our laboratory conditions; rebuild the liquid helium feeding system for the helium liquid tank and changed all the missed spare parts; redesigned the configuration for helium gas plant supplying system; vacuum test in order to determine that the leakage rates remain within tolerance levels; functioning tests for transfer line, oil-injected screw-compressor, helium recovery unit and electrical control unit. (authors)

  6. Cryogen-free dilution refrigerators

    International Nuclear Information System (INIS)

    Uhlig, K

    2012-01-01

    We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 μW at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4 He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4 He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

  7. Cryogen-free dilution refrigerators

    Science.gov (United States)

    Uhlig, K.

    2012-12-01

    We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 μW at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

  8. Cryogenics for HL-LHC

    Science.gov (United States)

    Tavian, L.; Brodzinski, K.; Claudet, S.; Ferlin, G.; Wagner, U.; van Weelderen, R.

    The discovery of a Higgs boson at CERN in 2012 is the start of a major program of work to measure this particle's properties with the highest possible precision for testing the validity of the Standard Model and to search for further new physics at the energy frontier. The LHC is in a unique position to pursue this program. Europe's top priority is the exploitation of the full potential of the LHC, including the high-luminosity upgrade of the machine and detectors with an objective to collect ten times more data than in the initial design, by around 2030. To reach this objective, the LHC cryogenic system must be upgraded to withstand higher beam current and higher luminosity at top energy while keeping the same operation availability by improving the collimation system and the protection of electronics sensitive to radiation. This chapter will present the conceptual design of the cryogenic system upgrade with recent updates in performance requirements, the corresponding layout and architecture of the system as well as the main technical challenges which have to be met in the coming years.

  9. The cryogenic storage ring CSR

    Science.gov (United States)

    von Hahn, R.; Becker, A.; Berg, F.; Blaum, K.; Breitenfeldt, C.; Fadil, H.; Fellenberger, F.; Froese, M.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; Heber, O.; Herwig, P.; Karthein, J.; Krantz, C.; Kreckel, H.; Lange, M.; Laux, F.; Lohmann, S.; Menk, S.; Meyer, C.; Mishra, P. M.; Novotný, O.; O'Connor, A. P.; Orlov, D. A.; Rappaport, M. L.; Repnow, R.; Saurabh, S.; Schippers, S.; Schröter, C. D.; Schwalm, D.; Schweikhard, L.; Sieber, T.; Shornikov, A.; Spruck, K.; Sunil Kumar, S.; Ullrich, J.; Urbain, X.; Vogel, S.; Wilhelm, P.; Wolf, A.; Zajfman, D.

    2016-06-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm-3 is derived, equivalent to a room-temperature pressure below 10-14 mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  10. The cryogenic storage ring CSR.

    Science.gov (United States)

    von Hahn, R; Becker, A; Berg, F; Blaum, K; Breitenfeldt, C; Fadil, H; Fellenberger, F; Froese, M; George, S; Göck, J; Grieser, M; Grussie, F; Guerin, E A; Heber, O; Herwig, P; Karthein, J; Krantz, C; Kreckel, H; Lange, M; Laux, F; Lohmann, S; Menk, S; Meyer, C; Mishra, P M; Novotný, O; O'Connor, A P; Orlov, D A; Rappaport, M L; Repnow, R; Saurabh, S; Schippers, S; Schröter, C D; Schwalm, D; Schweikhard, L; Sieber, T; Shornikov, A; Spruck, K; Sunil Kumar, S; Ullrich, J; Urbain, X; Vogel, S; Wilhelm, P; Wolf, A; Zajfman, D

    2016-06-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm(-3) is derived, equivalent to a room-temperature pressure below 10(-14) mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  11. The cryogenic storage ring CSR

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, R. von; Becker, A.; Berg, F.; Blaum, K.; Fadil, H.; Fellenberger, F.; Froese, M.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; Herwig, P.; Karthein, J.; Krantz, C.; Kreckel, H.; Lange, M.; Laux, F.; Lohmann, S.; Menk, S. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); and others

    2016-06-15

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm{sup −3} is derived, equivalent to a room-temperature pressure below 10{sup −14} mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  12. Terrestrial Analogs to Mars

    Science.gov (United States)

    Farr, T. G.; Arcone, S.; Arvidson, R. W.; Baker, V.; Barlow, N. G.; Beaty, D.; Bell, M. S.; Blankenship, D. D.; Bridges, N.; Briggs, G.; Bulmer, M.; Carsey, F.; Clifford, S. M.; Craddock, R. A.; Dickerson, P. W.; Duxbury, N.; Galford, G. L.; Garvin, J.; Grant, J.; Green, J. R.; Gregg, T. K. P.; Guinness, E.; Hansen, V. L.; Hecht, M. H.; Holt, J.; Howard, A.; Keszthelyi, L. P.; Lee, P.; Lanagan, P. D.; Lentz, R. C. F.; Leverington, D. W.; Marinangeli, L.; Moersch, J. E.; Morris-Smith, P. A.; Mouginis-Mark, P.; Olhoeft, G. R.; Ori, G. G.; Paillou, P.; Reilly, J. F., II; Rice, J. W., Jr.; Robinson, C. A.; Sheridan, M.; Snook, K.; Thomson, B. J.; Watson, K.; Williams, K.; Yoshikawa, K.

    2002-08-01

    It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites, instrument tests, laboratory measurements (including analysis of Martian meteorites), and computer and laboratory modeling. The combination of all these activities allows scientists to constrain the processes operating in specific terrestrial environments and extrapolate how similar processes could affect Mars. The Terrestrial Analogs for Mars Community Panel has considered the following two key questions: (1) How do terrestrial analog studies tie in to the Mars Exploration Payload Assessment Group science questions about life, past climate, and geologic evolution of Mars, and (2) How can future instrumentation be used to address these questions. The panel has considered the issues of data collection, value of field workshops, data archiving, laboratory measurements and modeling, human exploration issues, association with other areas of solar system exploration, and education and public outreach activities.

  13. Reasoning through Instructional Analogies

    Science.gov (United States)

    Kapon, Shulamit; diSessa, Andrea A.

    2012-01-01

    This article aims to account for students' assessments of the plausibility and applicability of analogical explanations, and individual differences in these assessments, by analyzing properties of students' underlying knowledge systems. We developed a model of explanation and change in explanation focusing on knowledge elements that provide a…

  14. Analogy, explanation, and proof

    Science.gov (United States)

    Hummel, John E.; Licato, John; Bringsjord, Selmer

    2014-01-01

    People are habitual explanation generators. At its most mundane, our propensity to explain allows us to infer that we should not drink milk that smells sour; at the other extreme, it allows us to establish facts (e.g., theorems in mathematical logic) whose truth was not even known prior to the existence of the explanation (proof). What do the cognitive operations underlying the inference that the milk is sour have in common with the proof that, say, the square root of two is irrational? Our ability to generate explanations bears striking similarities to our ability to make analogies. Both reflect a capacity to generate inferences and generalizations that go beyond the featural similarities between a novel problem and familiar problems in terms of which the novel problem may be understood. However, a notable difference between analogy-making and explanation-generation is that the former is a process in which a single source situation is used to reason about a single target, whereas the latter often requires the reasoner to integrate multiple sources of knowledge. This seemingly small difference poses a challenge to the task of marshaling our understanding of analogical reasoning to understanding explanation. We describe a model of explanation, derived from a model of analogy, adapted to permit systematic violations of this one-to-one mapping constraint. Simulation results demonstrate that the resulting model can generate explanations for novel explananda and that, like the explanations generated by human reasoners, these explanations vary in their coherence. PMID:25414655

  15. How Analogy Drives Physics

    International Nuclear Information System (INIS)

    Hofstadter, Doug

    2004-01-01

    Many new ideas in theoretical physics come from analogies to older ideas in physics. For instance, the abstract notion of 'isospin' (or isotopic spin) originated in the prior concept of 'spin' (quantized angular momentum); likewise, the concept of 'phonon' (quantum of sound, or quantized collective excitation of a crystal) was based on the prior concept of 'photon' (quantum of light, or quantized element of the electromagnetic field). But these two examples, far from being exceptions, in fact represent the bread and butter of inventive thinking in physics. In a nutshell, intraphysics analogy-making -- borrowing by analogy with something already known in another area of physics -- is central to the progress of physics. The aim of this talk is to reveal the pervasiveness -- indeed, the indispensability -- of this kind of semi-irrational, wholly intuitive type of thinking (as opposed to more deductive mathematical inference) in the mental activity known as 'doing physics'. Speculations as to why wild analogical leaps are so crucial to the act of discovery in physics (as opposed to other disciplines) will be offered.

  16. Quantum Analog Computing

    Science.gov (United States)

    Zak, M.

    1998-01-01

    Quantum analog computing is based upon similarity between mathematical formalism of quantum mechanics and phenomena to be computed. It exploits a dynamical convergence of several competing phenomena to an attractor which can represent an externum of a function, an image, a solution to a system of ODE, or a stochastic process.

  17. Cryogenic instrumentation with cold electronics-A review

    International Nuclear Information System (INIS)

    Rao, M.G.; Scurlock, R.G.

    1986-01-01

    The low level signals from cryogenic sensors and transducers are usually carried to the electronic signal conditioning and data handling systems at ambient temperatures by long electrical leads running from the cyrogenic environment to ambient. There are many applications, outside those using superconducting devices, in which there are advantages to be gained by placing part or all of the electronic system in the cryogenic environment adjacent to the measuring point. This paper discusses the requirements for an ideal cold electronic instrumentation system and then reviews the present state of the art in relation to off-the-shelf electronic components, devices and integrated circuits, and the published literature. The integration of sensors/transducers with cold electronics is discussed and areas for development are outlined

  18. Comparative analysis on flexibility requirements of typical Cryogenic Transfer lines

    Science.gov (United States)

    Jadon, Mohit; Kumar, Uday; Choukekar, Ketan; Shah, Nitin; Sarkar, Biswanath

    2017-04-01

    The cryogenic systems and their applications; primarily in large Fusion devices, utilize multiple cryogen transfer lines of various sizes and complexities to transfer cryogenic fluids from plant to the various user/ applications. These transfer lines are composed of various critical sections i.e. tee section, elbows, flexible components etc. The mechanical sustainability (under failure circumstances) of these transfer lines are primary requirement for safe operation of the system and applications. The transfer lines need to be designed for multiple design constraints conditions like line layout, support locations and space restrictions. The transfer lines are subjected to single load and multiple load combinations, such as operational loads, seismic loads, leak in insulation vacuum loads etc. [1]. The analytical calculations and flexibility analysis using professional software are performed for the typical transfer lines without any flexible component, the results were analysed for functional and mechanical load conditions. The failure modes were identified along the critical sections. The same transfer line was then refurbished with the flexible components and analysed for failure modes. The flexible components provide additional flexibility to the transfer line system and make it safe. The results obtained from the analytical calculations were compared with those obtained from the flexibility analysis software calculations. The optimization of the flexible component’s size and selection was performed and components were selected to meet the design requirements as per code.

  19. Cryogenic refrigeration. (Latest citations from the Aerospace database). Published Search

    International Nuclear Information System (INIS)

    1993-09-01

    The bibliography contains citations concerning cryogenic refrigeration or cryocooling. Design, development, testing, and evaluation of cryogenic cooling systems are discussed. Design applications in spacecraft, magnet cooling, superconductors, liquid fuel storage, radioastronomy, and medicine are presented. Material properties at cryogenic temperatures and cryogenic rocket propellants are considered in separate bibliographies. (Contains 250 citations and includes a subject term index and title list.)

  20. Effects of Multimedia and Schema Induced Analogical Reasoning on Science Learning

    Science.gov (United States)

    Zheng, R. Z.; Yang, W.; Garcia, D.; McCadden, E. P.

    2008-01-01

    The present study investigates the effects of multimedia and schema induced analogical reasoning on science learning. It involves 89 fourth grade elementary students in the north-east of the United States. Participants are randomly assigned into four conditions: (a) multimedia with analogy; (b) multimedia without analogy; (c) analogy without…

  1. Numerical Prediction of Magnetic Cryogenic Propellant Storage in Reduced Gravity

    Science.gov (United States)

    Marchetta, J. G.; Hochstein, J. I.

    2002-01-01

    Numerical Prediction of Magnetic Cryogenic Propellant Storage in Reduced strong evidence that a magnetic positioning system may be a feasible alternative technology for use in the management of cryogenic propellants onboard spacecraft. The results of these preliminary studies have indicated that further investigation of the physical processes and potential reliability of such a system is required. The utility of magnetic fields as an alternative method in cryogenic propellant management is dependent on its reliability and flexibility. Simulations and experiments have previously yielded evidence in support of the magnetic positive positioning (MPP) process to predictably reorient LOX for a variety of initial conditions. Presently, though, insufficient evidence has been established to support the use of magnetic fields with respect to the long-term storage of cryogenic propellants. Current modes of propellant storage have met with a moderate level of success and are well suited for short duration missions using monopropellants. However, the storage of cryogenic propellants warrants additional consideration for long-term missions. For example, propellant loss during storage is due to vaporization by incident solar radiation and the vaporized ullage must be vented to prevent excessive pressurization of the tank. Ideally, positioning the fluid in the center of the tank away from the tank wall will reduce vaporization by minimizing heat transfer through the tank wall to the liquid. A second issue involves the capability of sustaining a stable fluid configuration at tank center under varying g-levels or perturbations propellant storage. Results presented herein include comparisons illustrating the influence of gravity, fluid volume, and the magnetic field on a paramagnetic fluid, LOX. The magnetic Bond number is utilized as predictive correlating parameter for investigating these processes. A dimensionless relationship between the Bom and Bo was sought with the goal of

  2. Selected physico-mechanical characteristics of cryogenic and ambient ground turmeric

    Science.gov (United States)

    Barnwal, Pradyuman; Mohite, Ashish M.; Singh, Krishna K.; Kumar, Pankaj

    2014-03-01

    In this communication, selected physicomechanical characteristics of ground turmeric (cv. Prabha) were investigated for cryogenic and ambient grinding conditions of turmeric at different moisture contents (4, 6, 8 and 10% w.b.). A cryogenic grinder (Model: 100 UPZ, Hosokawa Alpine, Germany) and a micro pulverizer (hammer mill) were used for cryogenic and ambient grinding, respectively. The ground turmeric was graded in three grades viz. Gr-I, Gr-II and Gr-III with a sieve shaker using BSS Nos. 40, 85 and pan, respectively. Tap densities for cryogenic and ambient ground turmeric decreased from 678.7 (Gr-I) to 546.7 kgm-3 (Gr-III) and from 642.3 (Gr-I) to 468.6 kgm-3 (Gr-III), respectively, with the moisture increase. The angle of repose for cryogenic and ambient ground turmeric increased linearly from 26.85 (Gr-I) to 34.0° (Gr-III) and from 23.10 (Gr-I) to 28.06° (Gr-III), respectively with the increase in moisture content. The static coefficient of friction was the highest on plywood surface followed by mild steel sheet and galvanized iron sheet. The cryoground samples were found better in colour. Thermal conductivity of cryo-ground samples was higher than that of ambient ground samples. These physico-mechanical characteristics of cryogenic and ambient ground turmeric will be helpful for packaging, handling, and storage.

  3. Solid-cryogen-stabilized, cable-in-conduit (CIC) superconducting cables

    Science.gov (United States)

    Voccio, J. P.; Michael, P. C.; Bromberg, L.; Hahn, S.

    2015-12-01

    This paper considers the use of a solid cryogen as a means to stabilize, both mechanically and thermally, magnesium diboride (MgB2) superconducting strands within a dual-channel cable-in-conduit (CIC) cable for use in AC applications, such as a generator stator winding. The cable consists of two separate channels; the outer channel contains the superconducting strands and is filled with a fluid (liquid or gas) that becomes solid at the device operating temperature. Several options for fluid will be presented, such as liquid nitrogen, hydrocarbons and other chlorofluorocarbons (CFCs) that have a range of melting temperatures and volumetric expansions (from solid at operating temperature to fixed volume at room temperature). Implications for quench protection and conductor stability, enhanced through direct contact with the solid cryogen, which has high heat capacity and thermal conductivity (compared with helium gas), will be presented. Depending on the cryogen, the conductor will be filled initially either with liquid at atmospheric conditions or a gas at high pressure (∼100 atm). After cooldown, the cryogen in the stranded-channel will be solid, essentially locking the strands in place, preventing strand motion and degradation due to mechanical deformation while providing enhanced thermal capacity for stability and protection. The effect of cryogen porosity is also considered. The relatively high heat capacity of solid cryogens at these lower temperatures (compared to gaseous helium) enhances the thermal stability of the winding. During operation, coolant flow through the open inner channel will minimize pressure drop.

  4. StructUre and test results of the Tokamak-7 device cryogenic system

    International Nuclear Information System (INIS)

    Babaev, I.V.; VolobUev, A.N.; Zhul'kin, V.F.

    1982-01-01

    A cryogenic system (CS) of the Tokamak-7 (T-7) installation with the longitudinal field superconducting magnetic system (SMS) is described. The CS is designed for cool-down, cryostatic cooling and heating of the T-7 cryogenic objects and consists of a helium system (HS) and a nitrogen cryogenic system (NCS). The HS consists of:a a heliUm delivery system intended for distributing and controlling the helium flows in the SMS; cryogenic helium units; a 1.25 m 3 volume for storing liquid helium; a compressor compartment using piston compressors at the 3 MPa operating pressure and 140 g/s total capacity; gaseous helium storages (3600 m 3 under normal conditions); helium cleaning and drying systems; a gas holder of 20 m 3 operating volume; cryogenic pipelines and pipe fittings. The NCS operates on delivered nitrogen and includes a 120 m 3 liquid nitrogen storage, evaporators and electric heaters producing up to 230 g/s of gaseous nitrogen at 300 K, a separator, cryogenic pipelines and fittings. It is found that the CS has the necessary cold production reserve, ensures reliable operation of the Tokamak-7 device and permits to carry out practically continuous plasma experiments

  5. Real-Time Model-Based Leak-Through Detection within Cryogenic Flow Systems

    Science.gov (United States)

    Walker, M.; Figueroa, F.

    2015-01-01

    The timely detection of leaks within cryogenic fuel replenishment systems is of significant importance to operators on account of the safety and economic impacts associated with material loss and operational inefficiencies. Associated loss in control of pressure also effects the stability and ability to control the phase of cryogenic fluids during replenishment operations. Current research dedicated to providing Prognostics and Health Management (PHM) coverage of such cryogenic replenishment systems has focused on the detection of leaks to atmosphere involving relatively simple model-based diagnostic approaches that, while effective, are unable to isolate the fault to specific piping system components. The authors have extended this research to focus on the detection of leaks through closed valves that are intended to isolate sections of the piping system from the flow and pressurization of cryogenic fluids. The described approach employs model-based detection of leak-through conditions based on correlations of pressure changes across isolation valves and attempts to isolate the faults to specific valves. Implementation of this capability is enabled by knowledge and information embedded in the domain model of the system. The approach has been used effectively to detect such leak-through faults during cryogenic operational testing at the Cryogenic Testbed at NASA's Kennedy Space Center.

  6. Development of bonding techniques for cryogenic components (2). HIP bonding between Cu Alloys and Ti, cryogenic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Shigeru; Ouchi, Nobuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Fukaya, Kiyoshi [Nihon Advanced Technology Ltd., Tokai, Ibaraki (Japan); Ishiyama, Shintaro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Tsuchiya, Yoshinori; Nakajima, Hideo [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2003-03-01

    Several joints between dissimilar materials are required in the superconducting (SC) magnet system of SC linear accelerator or fusion reactor, Pure titanium (Ti) is one of candidate materials for a jacket of SC coil of fusion reactor because Ti is non-magnetic material and has a feature that its thermal expansion is similar to SC material in addition to good corrosion resistance and workability. Also, Ti does not require strict control of environment during reaction heat treatment of SC material. Copper (Cu) or Cu-alloy is used in electrical joints and cryogenic stainless steel (SS) is used in cryogenic pipes. Therefore, it is necessary to develop new bonding techniques for joints between Ti, Cu, and SS because jacket, electrical joint and cryogenic pipe have to be bonded each other to cool SC coils. Japan Atomic Energy Research Institute (JAERI) has started to develop dissimilar material joints bonded by hot isostatic pressing (HIP), which can bring a high strength joint with good tolerance and can applied to a large or complex geometry device. HIP conditions for Cu-Ti, Cu alloy-Ti, Cu alloy-SS were investigated in this study and most stable HIP condition were evaluated by microscopic observation, tensile and bending tests at room temperature. (author)

  7. Cryogenic system for TRISTAN superconducting RF cavity

    International Nuclear Information System (INIS)

    Hosoyama, K.; Hara, K.; Kabe, A.; Kojima, Yuuji; Ogitsu, T.; Sakamoto, Y.; Kawamura, S.; Ishimaru, Y.

    1990-01-01

    A cryogenic system consisting of a helium refrigerator (4 kW at 4.4 K) and a liquid helium distribution transfer system for TRISTAN 508 MHz 32 x 5-cell superconducting RF cavities was designed and constructed. After the performance test of the cryogenic system, 16 x 5-cell superconducting RF cavities in 8 cryostats were installed in underground TRISTAN electron-positron collider and connected to the helium refrigerator on the ground level through the transfer line (total length about 330 m) and cooled by liquid helium pool boiling in parallel. The cryogenic system and its operation experience are described. (author)

  8. Analog storage integrated circuit

    Science.gov (United States)

    Walker, J.T.; Larsen, R.S.; Shapiro, S.L.

    1989-03-07

    A high speed data storage array is defined utilizing a unique cell design for high speed sampling of a rapidly changing signal. Each cell of the array includes two input gates between the signal input and a storage capacitor. The gates are controlled by a high speed row clock and low speed column clock so that the instantaneous analog value of the signal is only sampled and stored by each cell on coincidence of the two clocks. 6 figs.

  9. Analogy, Explanation, and Proof

    Directory of Open Access Journals (Sweden)

    John eHummel

    2014-11-01

    Full Text Available People are habitual explanation generators. At its most mundane, our propensity to explain allows us to infer that we should not drink milk that smells sour; at the other extreme, it allows us to establish facts (e.g., theorems in mathematical logic whose truth was not even known prior to the existence of the explanation (proof. What do the cognitive operations underlying the (inductive inference that the milk is sour have in common with the (deductive proof that, say, the square root of two is irrational? Our ability to generate explanations bears striking similarities to our ability to make analogies. Both reflect a capacity to generate inferences and generalizations that go beyond the featural similarities between a novel problem and familiar problems in terms of which the novel problem may be understood. However, a notable difference between analogy-making and explanation-generation is that the former is a process in which a single source situation is used to reason about a single target, whereas the latter often requires the reasoner to integrate multiple sources of knowledge. This small-seeming difference poses a challenge to the task of marshaling our understanding of analogical reasoning in the service of understanding explanation. We describe a model of explanation, derived from a model of analogy, adapted to permit systematic violations of this one-to-one mapping constraint. Simulation results demonstrate that the resulting model can generate explanations for novel explananda and that, like the explanations generated by human reasoners, these explanations vary in their coherence.

  10. Cryogenic polarized target facility: status

    International Nuclear Information System (INIS)

    Gould, C.; Nash, H.K.; Roberson, N.; Schneider, M.; Seagondollar, W.; Soderstrum, J.

    1985-01-01

    The TUNL cryogenically polarized target facility consists of a 3 He- 4 He dilution refrigerator and a superconducting magnet, together capable of maintaining samples at between 10 and 20 mK in magnetic fields up to 7 Tesla. At these temperatures and magnetic fields brute-force nuclear orientation occurs. Polarizations from 20 to 60% are attainable in about twenty nonzero spin nuclei. Most are metals, ranging in mass from 6 Li to 209 Bi, but the nuclei 1 H and 3 He are also polarizable via this method. The main effort is directed towards a better determination of the effective spin-spin force in nuclei. These experiments are briefly described and the beam stabilization system, cryostat and polarized 3 He targets are discussed

  11. Computed tomography of cryogenic cells

    International Nuclear Information System (INIS)

    Schneider, Gerd; Anderson, E.; Vogt, S.; Knochel, C.; Weiss, D.; LeGros, M.; Larabell, C.

    2001-01-01

    Due to the short wavelengths of X-rays and low numerical aperture of the Fresnel zone plates used as X-ray objectives, the depth of field is several microns. Within the focal depth, imaging a thick specimen is to a good approximation equivalent to projecting the specimen absorption. Therefore, computed tomography based on a tilt series of X-ray microscopic images can be used to reconstruct the local linear absorption coefficient and image the three-dimensional specimen structure. To preserve the structural integrity of biological objects during image acquisition, microscopy is performed at cryogenic temperatures. Tomography based on X-ray microscopic images was applied to study the distribution of male specific lethal 1 (MSL-1), a nuclear protein involved in dosage compensation in Drosophila melanogaster, which ensures that males with single X chromosome have the same amount of most X-linked gene products as females with two X chromosomes. Tomographic reconstructions of X-ray microscopic images were used to compute the local three-dimensional linear absorption coefficient revealing the arrangement of internal structures of Drosophila melanogaster cells. Combined with labelling techniques, nanotomography is a new technique to study the 3D distribution of selected proteins inside whole cells. We want to improve this technique with respect to resolution and specimen preparation. The resolution in the reconstruction can be significantly improved by reducing the angular step size to collect more viewing angles, which requires an automated data acquisition. In addition, fast-freezing with liquid ethane instead of cryogenic He gas will be applied to improve the vitrification of the hydrated samples. We also plan to apply cryo X-ray nanotomography in order to study different types of cells and their nuclear protein distributions

  12. Metrological analysis of a virtual flowmeter-based transducer for cryogenic helium

    Energy Technology Data Exchange (ETDEWEB)

    Arpaia, P., E-mail: pasquale.arpaia@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Girone, M., E-mail: mario.girone@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Department of Engineering, University of Sannio, Benevento (Italy); Liccardo, A., E-mail: annalisa.liccardo@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Pezzetti, M., E-mail: marco.pezzetti@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Piccinelli, F., E-mail: fabio.piccinelli@cern.ch [Department of Mechanical Engineering, University of Brescia, Brescia (Italy)

    2015-12-15

    The metrological performance of a virtual flowmeter-based transducer for monitoring helium under cryogenic conditions is assessed. At this aim, an uncertainty model of the transducer, mainly based on a valve model, exploiting finite-element approach, and a virtual flowmeter model, based on the Sereg-Schlumberger method, are presented. The models are validated experimentally on a case study for helium monitoring in cryogenic systems at the European Organization for Nuclear Research (CERN). The impact of uncertainty sources on the transducer metrological performance is assessed by a sensitivity analysis, based on statistical experiment design and analysis of variance. In this way, the uncertainty sources most influencing metrological performance of the transducer are singled out over the input range as a whole, at varying operating and setting conditions. This analysis turns out to be important for CERN cryogenics operation because the metrological design of the transducer is validated, and its components and working conditions with critical specifications for future improvements are identified.

  13. Component Processes in Analogical Reasoning

    Science.gov (United States)

    Sternberg, Robert J.

    1977-01-01

    Describes alternative theoretical positions regarding (a) the component information processes used in analogical reasoning and (b) strategies for combining these processes. Also presents results from three experiments on analogical reasoning. (Author/RK)

  14. The Liquid Krypton Calorimeter Cryogenics for the NA48 Experiment

    CERN Document Server

    Bremer, J; Dauvergne, J P; Gonidec, A; Kesseler, G; Kubischta, Werner; Linser, G; Schinzel, D; Taureg, Hans; Wertelaers, Piet

    1998-01-01

    The NA48 cryogenic system has to provide stable thermal conditions (120 K) in a 9000 liter liquid krypton calorimeter, and has to ensure safe and loss free storage of the liquid during idle periods. Direct cooling of the krypton by nitrogen is used in emergency cases, while an intermediate cooler, containing saturated liquid argon at around 10 bar (117 K) is used under normal operation conditions when high thermal stability is needed. The krypton pressure is, during data taking, regulated to a value of (1.05 ± 0.01) bar for a period of about 8 months of continuous operation of the calorimeter.

  15. Cryogenic flow rate measurement with a laser Doppler velocimetry standard

    Science.gov (United States)

    Maury, R.; Strzelecki, A.; Auclercq, C.; Lehot, Y.; Loubat, S.; Chevalier, J.; Ben Rayana, F.

    2018-03-01

    A very promising alternative to the state-of-the-art static volume measurements for liquefied natural gas (LNG) custody transfer processes is the dynamic principle of flow metering. As the Designated Institute (DI) of the LNE (‘Laboratoire National de métrologie et d’Essais’, being the French National Metrology Institute) for high-pressure gas flow metering, Cesame-Exadebit is involved in various research and development programs. Within the framework of the first (2010-2013) and second (2014-2017) EURAMET Joint Research Project (JRP), named ‘Metrological support for LNG custody transfer and transport fuel applications’, Cesame-Exadebit explored a novel cryogenic flow metering technology using laser Doppler velocimetry (LDV) as an alternative to ultrasonic and Coriolis flow metering. Cesame-Exadebit is trying to develop this technique as a primary standard for cryogenic flow meters. Currently, cryogenic flow meters are calibrated at ambient temperatures with water. Results are then extrapolated to be in the Reynolds number range of real applications. The LDV standard offers a unique capability to perform online calibration of cryogenic flow meters in real conditions (temperature, pressure, piping and real flow disturbances). The primary reference has been tested on an industrial process in a LNG terminal during truck refuelling. The reference can calibrate Coriolis flow meters being used daily with all the real environmental constraints, and its utilisation is transparent for LNG terminal operators. The standard is traceable to Standard International units and the combined extended uncertainties have been determined and estimated to be lower than 0.6% (an ongoing improvement to reducing the correlation function uncertainty, which has a major impact in the uncertainty estimation).

  16. Spray-On Foam Insulations for Launch Vehicle Cryogenic Tanks

    Science.gov (United States)

    Fesmire, J. E.; Cofman, B. E.; Menghelli, B. J.; Heckle, K. W.

    2011-01-01

    Spray-on foam insulation (SOFI) has been developed for use on the cryogenic tanks of space launch vehicles beginning in the 1960s with the Apollo program. The use of SOFI was further developed for the Space Shuttle program. The External Tank (ET) of the Space Shuttle, consisting of a forward liquid oxygen tank in line with an aft liquid hydrogen tank, requires thermal insulation over its outer surface to prevent ice formation and avoid in-flight damage to the ceramic tile thermal protection system on the adjacent Orbiter. The insulation also provides system control and stability with throughout the lengthy process of cooldown, loading, and replenishing the tank. There are two main types of SOFI used on the ET: acreage (with the rind) and closeout (machined surface). The thermal performance of the seemingly simple SOFI system is a complex of many variables starting with the large temperature difference of from 200 to 260 K through the typical 25-mm thickness. Environmental factors include air temperature and humidity, wind speed, solar exposure, and aging or weathering history. Additional factors include manufacturing details, launch processing operations, and number of cryogenic thermal cycles. The study of the cryogenic thermal performance of SOFI under large temperature differentials is the subject of this article. The amount of moisture taken into the foam during the cold soak phase, termed Cryogenic Moisture Uptake, must also be considered. The heat leakage rates through these foams were measured under representative conditions using laboratory standard liquid nitrogen boiloff apparatus. Test articles included baseline, aged, and weathered specimens. Testing was performed over the entire pressure range from high vacuum to ambient pressure. Values for apparent thermal conductivity and heat flux were calculated and compared with prior data. As the prior data of record was obtained for small temperature differentials on non-weathered foams, analysis of the

  17. Spray-on foam insulations for launch vehicle cryogenic tanks

    Science.gov (United States)

    Fesmire, J. E.; Coffman, B. E.; Meneghelli, B. J.; Heckle, K. W.

    2012-04-01

    Spray-on foam insulation (SOFI) has been developed for use on the cryogenic tanks of space launch vehicles beginning in the 1960s with the Apollo program. The use of SOFI was further developed for the Space Shuttle program. The External Tank (ET) of the Space Shuttle, consisting of a forward liquid oxygen tank in line with an aft liquid hydrogen tank, requires thermal insulation over its outer surface to prevent ice formation and avoid in-flight damage to the ceramic tile thermal protection system on the adjacent Orbiter. The insulation also provides system control and stability throughout the lengthy process of cooldown, loading, and replenishing the tank. There are two main types of SOFI used on the ET: acreage (with the rind) and closeout (machined surface). The thermal performance of the seemingly simple SOFI system is a complex array of many variables starting with the large temperature difference of 200-260 K through the typical 25-mm thickness. Environmental factors include air temperature and humidity, wind speed, solar exposure, and aging or weathering history. Additional factors include manufacturing details, launch processing operations, and number of cryogenic thermal cycles. The study of the cryogenic thermal performance of SOFI under large temperature differentials is the subject of this article. The amount of moisture taken into the foam during the cold soak phase, termed Cryogenic Moisture Uptake, must also be considered. The heat leakage rates through these foams were measured under representative conditions using laboratory standard liquid nitrogen boiloff apparatus. Test articles included baseline, aged, and weathered specimens. Testing was performed over the entire pressure range from high vacuum to ambient pressure. Values for apparent thermal conductivity and heat flux were calculated and compared with prior data. As the prior data of record was obtained for small temperature differentials on non-weathered foams, analysis of the different

  18. Periodic flow hydrodynamic resistance parameters for woven screen matrices at cryogenic temperatures

    Science.gov (United States)

    Perrella, M. D.; Ghiaasiaan, S. M.

    2017-12-01

    The regenerator is a critical component in all Stirling and Pulse Tube cryocoolers. It generally consists of a microporous metallic or rare-earth filler material contained within a cylindrical shell. Accurate modelling of the hydrodynamic and thermal behaviour of different regenerator materials is crucial to the successful design of cryogenic systems. Previous investigations have used experimental measurements at steady and periodic flow conditions in conjunction with pore-level CFD analysis to determine the pertinent hydrodynamic parameters, namely the Darcy permeability and Forchheimer coefficients. Due to the difficulty associated with experimental measurement at cryogenic temperatures, past investigations were mostly performed at ambient conditions and their results are assumed to be appropriate for cryogenic temperatures. In this study, a regenerator filled with woven screen matrices such as 400 mesh T316 stainless steel were assembled and experimentally tested under periodic helium flow at cryogenic temperatures. The mass flow and pressure drop data were analysed using CFD to determine the dimensionless friction factor, Darcy Permeability and Forchheimer coefficients. These results are compared to previous investigations at ambient temperature conditions, and the relevance of room-temperature models and correlations to cryogenic temperatures is critically assessed.

  19. Inductive, Analogical, and Communicative Generalization

    Directory of Open Access Journals (Sweden)

    Adri Smaling

    2003-03-01

    Full Text Available Three forms of inductive generalization - statistical generalization, variation-based generalization and theory-carried generalization - are insufficient concerning case-to-case generalization, which is a form of analogical generalization. The quality of case-to-case generalization needs to be reinforced by setting up explicit analogical argumentation. To evaluate analogical argumentation six criteria are discussed. Good analogical reasoning is an indispensable support to forms of communicative generalization - receptive and responsive (participative generalization — as well as exemplary generalization.

  20. Analog circuit design a tutorial guide to applications and solutions

    CERN Document Server

    Williams, Jim

    2011-01-01

    * Covers the fundamentals of linear/analog circuit and system design to guide engineers with their design challenges. * Based on the Application Notes of Linear Technology, the foremost designer of high performance analog products, readers will gain practical insights into design techniques and practice. * Broad range of topics, including power management tutorials, switching regulator design, linear regulator design, data conversion, signal conditioning, and high frequency/RF design. * Contributors include the leading lights in analog design, Robert Dobkin, Jim Willia

  1. The analogic model ''RIC'' of thermal behaviour of mass concrete

    International Nuclear Information System (INIS)

    Gonzalez Redondo, M.; Gonzalez de Posada, F.; Plana Claver, J.

    1997-01-01

    In order to study the thermal field and calorific flows in heat sources (i.e. mass concrete during setting) we have conceived, built and experimented with an analogical electric model. This model, named RIC, consists of resistors (R) and capacitors (C) in which nodes an electric current (I) has been injected. Several analogical constants were used for the mathematical approximation. Thus, this paper describes the analogical RIC model, simulating heat generation, boundary and initial conditions and concreting. (Author) 4 refs

  2. Cryogenic Safety Rules and Guidelines at CERN

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    CERN defines and implements a Safety Policy that sets out the general principles governing safety at CERN. As an intergovernmental organisation, CERN further establishes its own Safety Rules as necessary for its proper functioning. In this process, it takes into account the laws and regulation of the Host States (France and Switzerland), EU regulations and directives, as well as international regulations, standards and directives. For the safety of cryogenic equipment, this is primarily covered by the Safety Regulation for Mechanical Equipment and the General Safety Instruction for Cryogenic Equipment. In addition, CERN has also developed Safety Guidelines to support the implementation of these safety rules, covering cryogenic equipment and oxygen deficiency hazard assessment and mitigation. An overview of the cryogenic safety rules and these safety guidelines will be presented.

  3. Temperature Stratification in a Cryogenic Fuel Tank

    Data.gov (United States)

    National Aeronautics and Space Administration — A reduced dynamical model describing temperature stratification effects driven by natural convection in a liquid hydrogen cryogenic fuel tank has been developed. It...

  4. The cryogenic control system of BEPCⅡ

    Institute of Scientific and Technical Information of China (English)

    LI Gang; WANG Ke-Xiang; ZHAO Ji-Jiu; YUE Ke-Juan; DAI Ming-Sui; HUANG Yi-Ling; JIANG Bo

    2008-01-01

    A superconducting cryogenic system has been designed and deployed in the Beijing Electron-Positron Collider Upgrade Project(BEPCⅡ).The system consists of a Siemens PLC(ST-PLC,Programmable Logic Controller)for the compressor control,an Allen Bradley(AB)PLC for the cryogenic equipments,and the Experimental Physics and Industrial Control System(EPICS)that integrates the PLCs.The system fully automates the superconducting cryogenic control with process control,PID(Proportional-Integral-Differential)control loops,real-time data access and data storage,alarm handler and human machine interface.It is capable of automatic recovery as well.This paper describes the BEPCⅡ cryogenic control system,data communication between ST-PLC and EPICS Input/Output Controllers(IOCs),and the integration of the flow control,the low level interlock,the AB-PLC,and EPICS.

  5. Cryogenic Insulation Standard Data and Methodologies

    Data.gov (United States)

    National Aeronautics and Space Administration — Extending some recent developments in the area of technical consensus standards for cryogenic thermal insulation systems, a preliminary Inter-Laboratory Study of...

  6. Status of the LBNF Cryogenic System

    CERN Document Server

    Montanari, D; Bremer, J; Delany, M; Diaz, A; Doubnik, R; Haaf, K; Henstchel, S; Norris, B; Voirin, E

    2017-01-01

    The Sanford Underground Research Facility (SURF) will host the Deep Underground Neutrino Experiment (DUNE), an international multi-kiloton Long-Baseline neutrino experiment that will be installed about a mile underground in Lead, SD. In the current configuration four cryostats will contain a modular detector and a total of 68,400 tons of ultrapure liquid argon, with a level of impurities lower than 100 parts per trillion of oxygen equivalent contamination. The Long-Baseline Neutrino Facility (LBNF) provides the conventional facilities and the cryogenic infrastructure to support DUNE. The system is comprised of three sub-systems: External/Infrastructure, Proximity and Internal cryogenics. An international engineering team will design, manufacture, commission, and qualify the LBNF cryogenic system. This contribution presents the modes of operations, layout and main features of the LBNF cryogenic system. The expected performance, the functional requirements and the status of the design are also highlighted.

  7. Cryogenic target formation using cold gas jets

    International Nuclear Information System (INIS)

    Hendricks, C.D.

    1980-01-01

    A method and apparatus using cold gas jets for producing a substantially uniform layer of cryogenic materials on the inner surface of hollow spherical members having one or more layers, such as inertially imploded targets, are described. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on an inner surface of the spherical member. Basically the method involves directing cold gas jets onto a spherical member having one or more layers or shells and containing the cryogenic material, such as a deuterium-tritium (DT) mixture, to freeze the contained material, momentarily heating the spherical member so as to vaporize the contained material, and quickly refreezing the thus vaporized material forming a uniform layer of cryogenic material on an inner surface of the spherical member

  8. Cryogenic MEMS Pressure Sensor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A directly immersible cryogenic MEMS pressure sensor will be developed. Each silicon die will contain a vacuum-reference and a tent-like membrane. Offsetting thermal...

  9. Status of the LBNF Cryogenic System

    Science.gov (United States)

    Montanari, D.; Adamowski, M.; Bremer, J.; Delaney, M.; Diaz, A.; Doubnik, R.; Haaf, K.; Hentschel, S.; Norris, B.; Voirin, E.

    2017-12-01

    The Sanford Underground Research Facility (SURF) will host the Deep Underground Neutrino Experiment (DUNE), an international multi-kiloton Long-Baseline neutrino experiment that will be installed about a mile underground in Lead, SD. In the current configuration four cryostats will contain a modular detector and a total of 68,400 tons of ultrapure liquid argon, with a level of impurities lower than 100 parts per trillion of oxygen equivalent contamination. The Long-Baseline Neutrino Facility (LBNF) provides the conventional facilities and the cryogenic infrastructure to support DUNE. The system is comprised of three sub-systems: External/Infrastructure, Proximity and Internal cryogenics. An international engineering team will design, manufacture, commission, and qualify the LBNF cryogenic system. This contribution presents the modes of operations, layout and main features of the LBNF cryogenic system. The expected performance, the functional requirements and the status of the design are also highlighted.

  10. Reliability of analog quantum simulation

    Energy Technology Data Exchange (ETDEWEB)

    Sarovar, Mohan [Sandia National Laboratories, Digital and Quantum Information Systems, Livermore, CA (United States); Zhang, Jun; Zeng, Lishan [Shanghai Jiao Tong University, Joint Institute of UMich-SJTU, Key Laboratory of System Control and Information Processing (MOE), Shanghai (China)

    2017-12-15

    Analog quantum simulators (AQS) will likely be the first nontrivial application of quantum technology for predictive simulation. However, there remain questions regarding the degree of confidence that can be placed in the results of AQS since they do not naturally incorporate error correction. Specifically, how do we know whether an analog simulation of a quantum model will produce predictions that agree with the ideal model in the presence of inevitable imperfections? At the same time there is a widely held expectation that certain quantum simulation questions will be robust to errors and perturbations in the underlying hardware. Resolving these two points of view is a critical step in making the most of this promising technology. In this work we formalize the notion of AQS reliability by determining sensitivity of AQS outputs to underlying parameters, and formulate conditions for robust simulation. Our approach naturally reveals the importance of model symmetries in dictating the robust properties. To demonstrate the approach, we characterize the robust features of a variety of quantum many-body models. (orig.)

  11. Analogical Reasoning and Computer Programming.

    Science.gov (United States)

    Clement, Catherine A.; And Others

    1986-01-01

    A study of correlations between analogical reasoning and Logo programming mastery among female high school students related the results of pretests of analogical reasoning to posttests of programming mastery. A significant correlation was found between analogical reasoning and the ability to write subprocedures for use in several different…

  12. Some of the QRL team in UJ22 of the LHC tunnel, where the last sector of the cryogenic distribution line was installed.

    CERN Multimedia

    Viviane Li

    2006-01-01

    The cryogenic distribution line "the QRL" is a circle built in 8 sectors, each approximately 3 km in length. It will circulate helium in liquid and gas phases, at different temperatures and pressures, to provide the cryogenic conditions for the superconducting magnets in the LHC tunnel.

  13. Modified friction factor correlation for CICC's based on a porous media analogy

    Science.gov (United States)

    Lewandowska, Monika; Bagnasco, Maurizio

    2011-09-01

    A modified correlation for the bundle friction factor in CICC's based on a porous media analogy is presented. The correlation is obtained by the analysis of the collected pressure drop data measured for 23 CICC's. The friction factors predicted by the proposed correlation are compared with those resulting from the pressure drop data for two CICC's measured recently using cryogenic helium in the SULTAN test facility at EPFL-CRPP.

  14. Neutron detection with cryogenics and semiconductors

    International Nuclear Information System (INIS)

    Bell, Zane W.; Carpenter, D.A.; Cristy, S.S.; Lamberti, V.E.; Burger, Arnold; Woodfield, Brian F.; Niedermayr, Thomas; Dragos Hau, I.; Labov, Simon E.; Friedrich, Stephan; Geoffrey West, W.; Pohl, Kenneth R.; Berg, Lodewijk van den

    2005-01-01

    The common methods of neutron detection are reviewed with special attention paid to the application of cryogenics and semiconductors to the problem. The authors' work with LiF- and boron-based cryogenic instruments is described as well as the use of CdTe and HgI 2 for direct detection of neutrons. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Surface tension confined liquid cryogen cooler

    Science.gov (United States)

    Castles, Stephen H. (Inventor); Schein, Michael E. (Inventor)

    1989-01-01

    A cryogenic cooler is provided for use in craft such as launch, orbital, and space vehicles subject to substantial vibration, changes in orientation, and weightlessness. The cooler contains a small pore, large free volume, low density material to restrain a cryogen through surface tension effects during launch and zero-g operations and maintains instrumentation within the temperature range of 10 to 140 K. The cooler operation is completely passive, with no inherent vibration or power requirements.

  16. A hall for assembly and cryogenic tests

    International Nuclear Information System (INIS)

    Beaunier, J.; Buhler, S.; Caruette, A.; Chevrollier, R.; Junquera, T.; Le Scornet, J.C.

    1999-01-01

    Cryodrome, an assembly hall and the testing ground for cryogenic equipment and R and D experiments for the superconducting cavities is going to be transformed for its future missions. The cryogenic utilities, especially the He low pressure pumping capacity, was rearranged and extended to a new area. Space was provided to install CRYHOLAB, a new horizontal cryostat for cavity testing. Automatic control and supervision of the utilities and the experimental area are rebuilt and updated. (authors)

  17. Analogical scaffolding: Making meaning in physics through representation and analogy

    Science.gov (United States)

    Podolefsky, Noah Solomon

    This work reviews the literature on analogy, introduces a new model of analogy, and presents a series of experiments that test and confirm the utility of this model to describe and predict student learning in physics with analogy. Pilot studies demonstrate that representations (e.g., diagrams) can play a key role in students' use of analogy. A new model of analogy, Analogical Scaffolding, is developed to explain these initial empirical results. This model will be described in detail, and then applied to describe and predict the outcomes of further experiments. Two large-scale (N>100) studies will demonstrate that: (1) students taught with analogies, according to the Analogical Scaffolding model, outperform students taught without analogies on pre-post assessments focused on electromagnetic waves; (2) the representational forms used to teach with analogy can play a significant role in student learning, with students in one treatment group outperforming students in other treatment groups by factors of two or three. It will be demonstrated that Analogical Scaffolding can be used to predict these results, as well as finer-grained results such as the types of distracters students choose in different treatment groups, and to describe and analyze student reasoning in interviews. Abstraction in physics is reconsidered using Analogical Scaffolding. An operational definition of abstraction is developed within the Analogical Scaffolding framework and employed to explain (a) why physicists consider some ideas more abstract than others in physics, and (b) how students conceptions of these ideas can be modeled. This new approach to abstraction suggests novel approaches to curriculum design in physics using Analogical Scaffolding.

  18. Experimental investigation of optical fiber temperature sensors at cryogenic temperature and in high magnetic fields

    International Nuclear Information System (INIS)

    Tanaka, Y.; Ogata, M.; Nagashima, K.; Agawa, H.; Matsuura, S.; Kumagai, Y.

    2010-01-01

    If it is possible to monitor the conditions in the cryogenic equipments including the super-conducting magnets, the indication of failure can be detected beforehand and the reliability in the operation can improve. Optical fiber temperature sensing is an advantageous method in terms of heat invasion, electric insulation, etc. Therefore, the experiments which confirm the characteristics of optical fiber temperature sensors at cryogenic temperatures and in high magnetic fields were performed, and the possibility of measuring under these conditions was confirmed. However, since the resolution of temperature was a problem, the method of analysis that predicts the measurements was contrived, and the method to improve the problem was examined.

  19. Academic Training: Introduction to cryogenic Engineering

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 5, 6, 7, 8 and 9 December from 11:00 to 12:00 - Main Auditorium, bldg. 500 Introduction to cryogenic Engineering by G. Perinic - CERN-AT Cryogenic engineering is one of the key technologies at CERN. It is widely used in research and has many applications in industry and last but not least in medicine. In research cryogenic engineering and its applications are omnipresent from the smallest laboratories to fusion reactors, huge detectors and accelerators. With the termination of the LHC, CERN will in fact become the world’s largest cryogenic installation. This series of talks intends to introduce the non-cryogenist to the basic principles and challenges of cryogenic engineering and its applications. The course will also provide a basis for practical application as well as for further learning. Monday 5.12.2005 Introduction: From History to Modern Refrigeration Cycles (Goran Perinic) Tuesday 6.12.2005 Refrigerants, Standard Cryostats, Cryogenic Des...

  20. Academic Training: Introduction to cryogenic Engineering

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 5, 6, 7, 8 and 9 December from 11:00 to 12:00 - Main Auditorium, bldg. 500 Introduction to cryogenic Engineering by G. Perinic - CERN-AT Cryogenic engineering is one of the key technologies at CERN. It is widely used in research and has many applications in industry and last but not least in medicine. In research cryogenic engineering and its applications are omnipresent from the smallest laboratories to fusion reactors, hughe detectors and accelerators. With the termination of the LHC, CERN will in fact become the world's largest cryogenic installation. This series of talks intends to introduce the non-cryogenist to the basic principles and challenges of cryogenic engineering and its applications. The course will also provide a basis for practical application as well as for further learning. From history to modern refrigeration cycles (1/5) Refrigerants, standard cryostats, cryogenic design (2/5) Heat transfer and insulation (3/5) Safety in cryoge...

  1. Discrete Calculus by Analogy

    CERN Document Server

    Izadi, F A; Bagirov, G

    2009-01-01

    With its origins stretching back several centuries, discrete calculus is now an increasingly central methodology for many problems related to discrete systems and algorithms. The topics covered here usually arise in many branches of science and technology, especially in discrete mathematics, numerical analysis, statistics and probability theory as well as in electrical engineering, but our viewpoint here is that these topics belong to a much more general realm of mathematics; namely calculus and differential equations because of the remarkable analogy of the subject to this branch of mathemati

  2. ESD analog circuits and design

    CERN Document Server

    Voldman, Steven H

    2014-01-01

    A comprehensive and in-depth review of analog circuit layout, schematic architecture, device, power network and ESD design This book will provide a balanced overview of analog circuit design layout, analog circuit schematic development, architecture of chips, and ESD design.  It will start at an introductory level and will bring the reader right up to the state-of-the-art. Two critical design aspects for analog and power integrated circuits are combined. The first design aspect covers analog circuit design techniques to achieve the desired circuit performance. The second and main aspect pres

  3. Analogy Mapping Development for Learning Programming

    Science.gov (United States)

    Sukamto, R. A.; Prabawa, H. W.; Kurniawati, S.

    2017-02-01

    Programming skill is an important skill for computer science students, whereas nowadays, there many computer science students are lack of skills and information technology knowledges in Indonesia. This is contrary with the implementation of the ASEAN Economic Community (AEC) since the end of 2015 which is the qualified worker needed. This study provided an effort for nailing programming skills by mapping program code to visual analogies as learning media. The developed media was based on state machine and compiler principle and was implemented in C programming language. The state of every basic condition in programming were successful determined as analogy visualization.

  4. Cryogenic ion chemistry and spectroscopy.

    Science.gov (United States)

    Wolk, Arron B; Leavitt, Christopher M; Garand, Etienne; Johnson, Mark A

    2014-01-21

    The use of mass spectrometry in macromolecular analysis is an incredibly important technique and has allowed efficient identification of secondary and tertiary protein structures. Over 20 years ago, Chemistry Nobelist John Fenn and co-workers revolutionized mass spectrometry by developing ways to non-destructively extract large molecules directly from solution into the gas phase. This advance, in turn, enabled rapid sequencing of biopolymers through tandem mass spectrometry at the heart of the burgeoning field of proteomics. In this Account, we discuss how cryogenic cooling, mass selection, and reactive processing together provide a powerful way to characterize ion structures as well as rationally synthesize labile reaction intermediates. This is accomplished by first cooling the ions close to 10 K and condensing onto them weakly bound, chemically inert small molecules or rare gas atoms. This assembly can then be used as a medium in which to quench reactive encounters by rapid evaporation of the adducts, as well as provide a universal means for acquiring highly resolved vibrational action spectra of the embedded species by photoinduced mass loss. Moreover, the spectroscopic measurements can be obtained with readily available, broadly tunable pulsed infrared lasers because absorption of a single photon is sufficient to induce evaporation. We discuss the implementation of these methods with a new type of hybrid photofragmentation mass spectrometer involving two stages of mass selection with two laser excitation regions interfaced to the cryogenic ion source. We illustrate several capabilities of the cryogenic ion spectrometer by presenting recent applications to peptides, a biomimetic catalyst, a large antibiotic molecule (vancomycin), and reaction intermediates pertinent to the chemistry of the ionosphere. First, we demonstrate how site-specific isotopic substitution can be used to identify bands due to local functional groups in a protonated tripeptide designed to

  5. The performance of a piezoelectric-sensor-based SHM system under a combined cryogenic temperature and vibration environment

    International Nuclear Information System (INIS)

    Qing, Xinlin P; Beard, Shawn J; Kumar, Amrita; Sullivan, Kevin; Aguilar, Robert; Merchant, Munir; Taniguchi, Mike

    2008-01-01

    A series of tests have been conducted to determine the survivability and functionality of a piezoelectric-sensor-based active structural health monitoring (SHM) SMART Tape system under the operating conditions of typical liquid rocket engines such as cryogenic temperature and vibration loads. The performance of different piezoelectric sensors and a low temperature adhesive under cryogenic temperature was first investigated. The active SHM system for liquid rocket engines was exposed to flight vibration and shock environments on a simulated large booster LOX-H 2 engine propellant duct conditioned to cryogenic temperatures to evaluate the physical robustness of the built-in sensor network as well as operational survivability and functionality. Test results demonstrated that the developed SMART Tape system can withstand operational levels of vibration and shock energy on a representative rocket engine duct assembly, and is functional under the combined cryogenic temperature and vibration environment

  6. Design and construction of the SSCL magnet test laboratory cryogenic systems

    International Nuclear Information System (INIS)

    Freeman, M.A.; Kobel, T.A.

    1992-01-01

    The intent of this document is to provide a brief summary of the execution, by Process Systems International, Inc. (PSI), of the Design and Construction of the SSCL Magnet Test Laboratory Cryogenic Systems. This $30 million project requires the expenditure of over 200,000 manhours and the procurement of $17 million in materials within a two year period. SSC magnets will be performance tested at the Magnet Test Laboratory (MTL) and the Accelerator System String Test (ASST) facility under conditions simulating the environment of the SSC main ring. The cryogenic system consists of test stands (five for MTL, one for ASST) and the associated equipment including cryogenic storage, purification, thermal conditioning, and helium refrigeration necessary to support the test program

  7. Thermal stress state of cryogenic HP vessels under freezing and pressurization

    International Nuclear Information System (INIS)

    Tsybenko, A.S.; Kuranov, B.A.; Chepurnoj, A.D.; Shaposhnikov, V.A.; Krishchuk, N.G.

    1986-01-01

    A mathematical model is developed for thermomechanical processes in cryogenic HP vessels under freezing either by liquid and (or) gaseous cryogen and under pressurization. Equations of nonlinear nonstationary thermal conductivity and nonisothermal thermoelastoplasticity are used for the case of the theory off low with isotropic hardening. Semiempiricaldependences of nonstationary heat exchange for gaseous medium, experimental curves of cryogenic liquid boiling, mass exchange relationships are allowed for when formulating boundary conditions. The mathematical modelis realized on the basi of the finite element method in the form of highly automated program complex TERSOD (heat resistanceof vessels), oriented for computer of the Unified System. Heat and stress-strained states for three constructions of vessels are thoroughly studied under different conditions of gaseous, liquid and combined freezing with subsequent pressurization

  8. Cryogenic trapping of keV ion beams at the CSR prototype

    Energy Technology Data Exchange (ETDEWEB)

    Menk, Sebastian; Blaum, Klaus; Froese, Michael; Grieser, Manfred; Lange, Michael; Orlov, Dimitry; Sieber, Thomas; Hahn, Robert von; Varju, Jozef; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Heber, Oded; Rappaport, Michael; Zajfman, Daniel [Weizmann Institut of Science, Rehovot (Israel)

    2009-07-01

    A Cryogenic Trap for Fast ion beams (CTF) was built to explore cooling techniques and test thermal decoupling of ion optics for the development of the electrostatic Cryogenic Storage Ring (CSR). These challenging projects will lead to a new experimental field of atomic and molecular physics with keV ion beams. The cold conditions of 2-10 K minimize the blackbody radiation field and are expected to lead to extremely low restgas densities (equivalent pressure at room temperature {approx}10{sup -13} mbar) which result in long storage lifetimes and for molecular ions to radiative cooling to their ro-vibrational ground states. The CTF consists of two stacks of electrostatic mirror electrodes allowing the storage of up to 20 keV ion beams. Cryogenic ion beam storage has been realized with this device using a liquid helium refrigeration system to cool down the experimental trapping area to few-Kelvin cryogenic temperatures and experiments with cryogenically trapped molecular nitrogen ions have been performed to verify the low vacuum conditions by measuring their storage lifetimes.

  9. Progressive Tool Wear in Cryogenic Machining: The Effect of Liquid Nitrogen and Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Yusuf Kaynak

    2018-05-01

    Full Text Available This experimental study focuses on various cooling strategies and lubrication-assisted cooling strategies to improve machining performance in the turning process of AISI 4140 steel. Liquid nitrogen (LN2 and carbon dioxide (CO2 were used as cryogenic coolants, and their performances were compared with respect to progression of tool wear. Minimum quantity lubrication (MQL was also used with carbon dioxide. Progression of wear, including flank and nose, are the main outputs examined during experimental study. This study illustrates that carbon dioxide-assisted cryogenic machining alone and with minimum quantity lubrication does not contribute to decreasing the progression of wear within selected cutting conditions. This study also showed that carbon dioxide-assisted cryogenic machining helps to increase chip breakability. Liquid nitrogen-assisted cryogenic machining results in a reduction of tool wear, including flank and nose wear, in the machining process of AISI 4140 steel material. It was also observed that in the machining process of this material at a cutting speed of 80 m/min, built-up edges occurred in both cryogenic cooling conditions. Additionally, chip flow damage occurs in particularly dry machining.

  10. Mathematical Modeling of the Thermal Shell State of the Cylindrical Cryogenic Tank During Filling and Emptying

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2015-01-01

    Full Text Available Liquid hydrogen and oxygen are used as the oxidizer and fuel for liquid rocket engines. Liquefied natural gas, which is based on methane, is seen as a promising motor fuel for internal combustion engines. One of the technical problems arising from the use of said cryogenic liquid is to provide containers for storage, transport and use in the propulsion system. In the design and operation of such vessels it is necessary to have reliable information about their temperature condition, on which depend the loss of cryogenic fluids due to evaporation and the stress-strain state of the structural elements of the containers.Uneven temperature distribution along the generatrix of the cylindrical thin-walled shell of rocket cryogenic tanks, in a localized zone of cryogenic liquid level leads to a curvature of the shell and reduce the permissible axle load in a hazard shell buckling in the preparation for the start of the missile in flight with an increasing acceleration. Moving the level of the cryogenic liquid during filling or emptying the tank at a certain combination of parameters results in an increase of the local temperature distribution nonuniformity.Along with experimental study of the shell temperature state of the cryogenic container, methods of mathematical modeling allow to have information needed for designing and testing the construction of cryogenic tanks. In this study a mathematical model is built taking into account features of heat transfer in a cryogenic container, including the boiling cryogenic liquid in the inner surface of the container. This mathematical model describes the temperature state of the thin-walled shell of cylindrical cryogenic tank during filling and emptying. The work also presents a quantitative analysis of this model in case of fixed liquid level, its movement at a constant speed, and harmonic oscillations relative to a middle position. The quantitative analysis of this model has allowed to find the limit options

  11. Albert Einstein, Analogizer Extraordinaire

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    Where does deep insight in physics come from? It is tempting to think that it comes from the purest and most precise of reasoning, following ironclad laws of thought that compel the clear mind completely rigidly. And yet the truth is quite otherwise. One finds, when one looks closely at any major discovery, that the greatest of physicists are, in some sense, the most crazily daring and irrational of all physicists. Albert Einstein exemplifies this thesis in spades. In this talk I will describe the key role, throughout Albert Einstein's fabulously creative life, played by wild guesses made by analogy lacking any basis whatsoever in pure reasoning. In particular, in this year of 2007, the centenary of 1907, I will describe how over the course of two years (1905 through 1907) of pondering, Einstein slowly came, via analogy, to understand the full, radical consequences of the equation that he had first discovered and published in 1905, arguably the most famous equation of all time: E = mc2.

  12. Device for delivering cryogen to rotary super-conducting winding of cryogen-cooled electrical machine

    International Nuclear Information System (INIS)

    Filippov, I.F.; Gorbunov, G.S.; Khutoretsky, G.M.; Popov, J.S.; Skachkov, J.V.; Vinokurov, A.A.

    1980-01-01

    A device is disclosed for delivering cryogen to a superconducting winding of a cryogen-cooled electrical machine comprising a pipe articulated along the axis of the electrical machine and intended to deliver cryogen. One end of said pipe is located in a rotary chamber which communicates through channels with the space of the electrical machine, and said space accommodating its superconducting winding. The said chamber accommodates a needle installed along the chamber axis, and the length of said needle is of sufficient length such that in the advanced position of said cryogen delivering pipe said needle reaches the end of the pipe. The layout of the electrical machine increases the reliability and effectiveness of the device for delivering cryogen to the superconducting winding, simplifies the design of the device and raises the efficiency of the electrical machine

  13. Ion Acceleration by Laser Plasma Interaction from Cryogenic Microjets

    Energy Technology Data Exchange (ETDEWEB)

    Propp, Adrienne [Harvard Univ., Cambridge, MA (United States)

    2015-08-16

    Processes that occur in extreme conditions, such as in the center of stars and large planets, can be simulated in the laboratory using facilities such as SLAC National Accelerator Laboratory and the Jupiter Laser Facility (JLF) at Lawrence Livermore National Laboratory (LLNL). These facilities allow scientists to investigate the properties of matter by observing their interactions with high-power lasers. Ion acceleration from laser plasma interaction is gaining greater attention today due to its widespread potential applications, including proton beam cancer therapy and fast ignition for energy production. Typically, ion acceleration is achieved by focusing a high power laser on thin foil targets through a mechanism called Target Normal Sheath Acceleration. However, this mechanism is not ideal for creating the high-energy proton beams needed for future applications. Based on research and recent experiments, we hypothesized that a pure liquid cryogenic jet would be an ideal target for exploring new regimes of ion acceleration. Furthermore, it would provide a continuous, pure target, unlike metal foils which are consumed in the interaction and easily contaminated. In an effort to test this hypothesis, we used the 527 nm split beam, frequency-doubled TITAN laser at JLF. Data from the cryogenic jets was limited due to the flow of current up the jet into the nozzle during the interaction, heating the jet and damaging the orifice. However, we achieved a pure proton beam with evidence of a monoenergetic feature. Furthermore, data from gold and carbon wires showed surprising and interesting results. Preliminary analysis of data from two ion emission diagnostics, Thomson parabola spectrometers (TPs) and radio chromic films (RCFs), suggests that shockwave acceleration occurred rather than target normal sheath acceleration, the standard mechanism of ion acceleration. Upon completion of the experiment at TITAN, I researched the possibility of transforming our liquid cryogenic

  14. Ion Acceleration by Laser Plasma Interaction from Cryogenic Microjets

    International Nuclear Information System (INIS)

    Propp, Adrienne

    2015-01-01

    Processes that occur in extreme conditions, such as in the center of stars and large planets, can be simulated in the laboratory using facilities such as SLAC National Accelerator Laboratory and the Jupiter Laser Facility (JLF) at Lawrence Livermore National Laboratory (LLNL). These facilities allow scientists to investigate the properties of matter by observing their interactions with high-power lasers. Ion acceleration from laser plasma interaction is gaining greater attention today due to its widespread potential applications, including proton beam cancer therapy and fast ignition for energy production. Typically, ion acceleration is achieved by focusing a high power laser on thin foil targets through a mechanism called Target Normal Sheath Acceleration. However, this mechanism is not ideal for creating the high-energy proton beams needed for future applications. Based on research and recent experiments, we hypothesized that a pure liquid cryogenic jet would be an ideal target for exploring new regimes of ion acceleration. Furthermore, it would provide a continuous, pure target, unlike metal foils which are consumed in the interaction and easily contaminated. In an effort to test this hypothesis, we used the 527 nm split beam, frequency-doubled TITAN laser at JLF. Data from the cryogenic jets was limited due to the flow of current up the jet into the nozzle during the interaction, heating the jet and damaging the orifice. However, we achieved a pure proton beam with evidence of a monoenergetic feature. Furthermore, data from gold and carbon wires showed surprising and interesting results. Preliminary analysis of data from two ion emission diagnostics, Thomson parabola spectrometers (TPs) and radio chromic films (RCFs), suggests that shockwave acceleration occurred rather than target normal sheath acceleration, the standard mechanism of ion acceleration. Upon completion of the experiment at TITAN, I researched the possibility of transforming our liquid cryogenic

  15. Dynamics of cold helium flow inside a cryoline used for large cryogenic distribution system

    International Nuclear Information System (INIS)

    Kumar, Uday; Jadon, Mohit; Choukekar, Ketan; Shukla, Vinit; Patel, Pratik; Kapoor, Himanshu; Shah, Nitin; Muralidhara, Srinivasa; Sarkar, Biswanath

    2015-01-01

    The Cryolines, which by definition transfers cryogens from the source, normally a cryogenic plant, to several systems requiring cooling at cryogenic temperature to the level of 4 K and 80 K. The operations of cryolines are normally assumed to be steady state following a cool down from room temperature to the cryogenic temperature. It is to be noted that in a distributed cryogenic system, especially in a nuclear facility such as ITER having confinement definition due to the regulatory requirements, do also attract the attention in the system design that the release from safety valves cannot be allowed inside a building. Therefore, all safety valves need to be discharged inside a confined space, which is a specific space requiring fulfillment of definition for a cryogenic line. The specificity in such cases is that such cryogenic lines will realize dynamic conditions for each release of safety valves or a combination of safety valves in terms of pressure, temperature and flow, leading to unexpected failures. Such operating scenarios also lead to serious impact on fatigue with a question mark on the reliability. Therefore, one can define such cryolines as Relief Collection Header (RCH) which collects discharged helium and transport it to the appropriate place as defined in the system design. The discharges of cold helium from safety relief discharge ports of equipment can result into significantly unsteady and compressible flow in RCH. The proper design of the RCH has to be supported by detailed dynamic of expected flow phenomena for specific cases. The paper presents the dynamics of cold helium flow inside the typical RCH that has been performed to investigate the variation in flow parameters (pressure, temperature, velocity and density) along the axis of RCH and predictions on its reliability. (author)

  16. Repeatability of Cryogenic Multilayer Insulation

    Science.gov (United States)

    Johnson, W. L.; Vanderlaan, M.; Wood, J. J.; Rhys, N. O.; Guo, W.; Van Sciver, S.; Chato, D. J.

    2017-12-01

    Due to the variety of requirements across aerospace platforms, and one off projects, the repeatability of cryogenic multilayer insulation (MLI) has never been fully established. The objective of this test program is to provide a more basic understanding of the thermal performance repeatability of MLI systems that are applicable to large scale tanks. There are several different types of repeatability that can be accounted for: these include repeatability between identical blankets, repeatability of installation of the same blanket, and repeatability of a test apparatus. The focus of the work in this report is on the first two types of repeatability. Statistically, repeatability can mean many different things. In simplest form, it refers to the range of performance that a population exhibits and the average of the population. However, as more and more identical components are made (i.e. the population of concern grows), the simple range morphs into a standard deviation from an average performance. Initial repeatability testing on MLI blankets has been completed at Florida State University. Repeatability of five Glenn Research Center (GRC) provided coupons with 25 layers was shown to be +/- 8.4% whereas repeatability of repeatedly installing a single coupon was shown to be +/- 8.0%. A second group of 10 coupons has been fabricated by Yetispace and tested by Florida State University, the repeatability between coupons has been shown to be +/- 15-25%. Based on detailed statistical analysis, the data has been shown to be statistically significant.

  17. Cryogenic Deflashing for Rubber Products

    Directory of Open Access Journals (Sweden)

    Abhilash M.

    2018-01-01

    Full Text Available Deflashing is the process of removal of excess flashes from the rubber products. Initially deflashing was a manual operation where dozen of workers, seated at small work stations would take each part and trim the excess rubber off with scissors, knives or by grinding. Still the same method is employed in most of the rubber industry. The drawbacks of this method are demand inconsistent and repeatable quality. Work done by hand is often inconsistent. There are commercially available cryogenic deflashing machine but they are too expensive hence cost effectiveness is also a prime factor. The objective of this paper is to develop a technique, to identify the media through which the flashes can be removed easily and effectively. Based on the test results obtained from testing of five different types of media, ABCUT Steel media gave best results. The testing of the ABCUT Steel media on rubber samples like O-rings, grommet tail door, bottom bush etc. shows good results.

  18. Cryogenic helium gas convection research

    International Nuclear Information System (INIS)

    Donnelly, R.J.

    1994-10-01

    This is a report prepared by a group interested in doing research in thermal convection using the large scale refrigeration facilities available at the SSC Laboratories (SSCL). The group preparing this report consists of Michael McAshan at SSCL, Robert Behringer at Duke University, Katepalli Sreenivasan at Yale University, Xiao-Zhong Wu at Northern Illinois University and Russell Donnelly at the University of Oregon, who served as Editor for this report. This study reports the research and development opportunities in such a project, the technical requirements and feasibility of its construction and operation, and the costs associated with the needed facilities and support activities. The facility will be a unique national resource for studies of high-Reynolds-number and high-Rayleigh-number and high Rayleigh number turbulence phenomena, and is one of the six items determined as suitable for potential funding through a screening of Expressions of Interest. The proposed facility is possible only because of the advanced cryogenic technology available at the SSCL. Typical scientific issues to be addressed in the facility will be discussed. It devolved during our study, that while the main experiment is still considered to be the thermal convection experiment discussed in our original Expression of Interest, there are now a very substantial set of other, important and fundamental experiments which can be done with the large cryostat proposed for the convection experiment. We believe the facility could provide several decades of front-line research in turbulence, and shall describe why this is so

  19. A cryogenic infrared calibration target

    Science.gov (United States)

    Wollack, E. J.; Kinzer, R. E.; Rinehart, S. A.

    2014-04-01

    A compact cryogenic calibration target is presented that has a peak diffuse reflectance, R ⩽ 0.003, from 800 to 4800 cm-1 (12 - 2 μm). Upon expanding the spectral range under consideration to 400-10 000 cm-1 (25 - 1 μm) the observed performance gracefully degrades to R ⩽ 0.02 at the band edges. In the implementation described, a high-thermal-conductivity metallic substrate is textured with a pyramidal tiling and subsequently coated with a thin lossy dielectric coating that enables high absorption and thermal uniformity across the target. The resulting target assembly is lightweight, has a low-geometric profile, and has survived repeated thermal cycling from room temperature to ˜4 K. Basic design considerations, governing equations, and test data for realizing the structure described are provided. The optical properties of selected absorptive materials—Acktar Fractal Black, Aeroglaze Z306, and Stycast 2850 FT epoxy loaded with stainless steel powder—are characterized and presented.

  20. FABRICATION OF WINDOW SADDLES FOR NIF CRYOGENIC HOHLRAUMS

    International Nuclear Information System (INIS)

    GIRALDEZ, E; KAAE, J.L

    2003-09-01

    OAK-B135 A planar diagnostic viewing port attached to the cylindrical wall of the NIF cryogenic hohlraum requires a saddle-like transition piece. While the basic design of this window saddle is straightforward, its fabrication is not, given the scale and precision of the component. They solved the problem through the use of a two segment copper mandrel to electroform the gold window saddle. The segments were micro-machined using a combination of single-point diamond turning and single point diamond milling. These processes as well as the electroplating conditions, final machining and mandrel removal are described in this paper

  1. Deformation behavior of austenitic stainless steel at deep cryogenic temperatures

    Science.gov (United States)

    Han, Wentuo; Liu, Yuchen; Wan, Farong; Liu, Pingping; Yi, Xiaoou; Zhan, Qian; Morrall, Daniel; Ohnuki, Somei

    2018-06-01

    The nonmagnetic austenite steels are the jacket materials for low-temperature superconductors of fusion reactors. The present work provides evidences that austenites transform to magnetic martensite when deformation with a high-strain is imposed at 77 K and 4.2 K. The 4.2 K test is characterized by serrated yielding that is related to the specific motion of dislocations and phase transformations. The in-situ transmission electron microscope (TEM) observations in nanoscale reveal that austenites achieve deformation by twinning under low-strain conditions at deep cryogenic temperatures. The generations of twins, martensitic transformations, and serrated yielding are in order of increasing difficulty.

  2. Detecting analogical resemblance without retrieving the source analogy.

    Science.gov (United States)

    Kostic, Bogdan; Cleary, Anne M; Severin, Kaye; Miller, Samuel W

    2010-06-01

    We examined whether people can detect analogical resemblance to an earlier experimental episode without being able to recall the experimental source of the analogical resemblance. We used four-word analogies (e.g., robin-nest/beaver-dam), in a variation of the recognition-without-cued-recall method (Cleary, 2004). Participants studied word pairs (e.g., robin-nest) and were shown new word pairs at test, half of which analogically related to studied word pairs (e.g., beaver-dam) and half of which did not. For each test pair, participants first attempted to recall an analogically similar pair from the study list. Then, regardless of whether successful recall occurred, participants were prompted to rate the familiarity of the test pair, which was said to indicate the likelihood that a pair that was analogically similar to the test pair had been studied. Across three experiments, participants demonstrated an ability to detect analogical resemblance without recalling the source analogy. Findings are discussed in terms of their potential relevance to the study of analogical reasoning and insight, as well as to the study of familiarity and recognition memory.

  3. Feedback in analog circuits

    CERN Document Server

    Ochoa, Agustin

    2016-01-01

    This book describes a consistent and direct methodology to the analysis and design of analog circuits with particular application to circuits containing feedback. The analysis and design of circuits containing feedback is generally presented by either following a series of examples where each circuit is simplified through the use of insight or experience (someone else’s), or a complete nodal-matrix analysis generating lots of algebra. Neither of these approaches leads to gaining insight into the design process easily. The author develops a systematic approach to circuit analysis, the Driving Point Impedance and Signal Flow Graphs (DPI/SFG) method that does not require a-priori insight to the circuit being considered and results in factored analysis supporting the design function. This approach enables designers to account fully for loading and the bi-directional nature of elements both in the feedback path and in the amplifier itself, properties many times assumed negligible and ignored. Feedback circuits a...

  4. LASERS: A cryogenic slab CO laser

    Science.gov (United States)

    Ionin, Andrei A.; Kozlov, A. Yu; Seleznev, L. V.; Sinitsyn, D. V.

    2009-03-01

    A compact capacitive transverse RF-discharge-pumped slab CO laser with cryogenically cooled electrodes, which operates both in the cw and repetitively pulsed regimes, is fabricated. The laser operation is studied in the free running multifrequency regime at the vibrational - rotational transitions of the fundamental (V + 1 → V) vibrational bands of the CO molecule in the spectral region from 5.1 to 5.4 μm. Optimal operation conditions (gas mixture composition and pressure, RF pump parameters) are determined. It is shown that only gas mixtures with a high content of oxygen (up to 20% with respect to the concentration of CO molecules) can be used as an active medium of this laser. It is demonstrated that repetitively pulsed pumping is more efficient compared to cw pumping. In this case, quasi-cw lasing regime can be obtained. The maximum average output power of ~12 W was obtained for this laser operating on fundamental bands and its efficiency achieved ~14 %. The frequency-selective operation regime of the slab RF-discharge-pumped CO laser was realised at ~ 100 laser lines in the spectral region from 5.0 to 6.5 μm with the average output power of up to several tens of milliwatts in each line. Lasing at the transitions of the first vibrational overtone (V + 2 → V) of the CO molecule is obtained in the spectral region from 2.5 to 3.9 μm. The average output power of the overtone laser achieved 0.3 W. All the results were obtained without the forced gas mixture exchange in the discharge chamber. Under fixed experimental conditions, repetitively pulsed lasing (with fluctuations of the output characteristics no more than ±10 %) was stable for more than an hour.

  5. Cryogenic readout for multiple VUV4 Multi-Pixel Photon Counters in liquid xenon

    Science.gov (United States)

    Di Giovanni, A.

    2018-03-01

    This work concerned the preliminary tests and characterization of a cryogenic preamplifier board for an array made of 16 S13370-3050CN (VUV4 family) Multi-Pixel Photon Counters manufactured by Hamamatsu and operated at liquid xenon temperature. The proposed prototype is based on the use of the Analog Devices AD8011 current feedback operational amplifier. The detector allows for single photon detection, making this device a promising choice for the future generation of neutrino and dark matter detectors based on liquid xenon targets.

  6. The Future with Cryogenic Fluid Dynamics

    Science.gov (United States)

    Scurlock, R. G.

    The applications of cryogenic systems have expanded over the past 50 years into many areas of our lives. During this time, the impact of the common features of Cryogenic Fluid Dynamics, CryoFD, on the economic design of these cryogenic systems, has grown out of a long series of experimental studies carried out by teams of postgraduate students at Southampton University.These studies have sought to understand the heat transfer and convective behavior of cryogenic liquids and vapors, but they have only skimmed over the many findings made, on the strong convective motions of fluids at low temperatures. The convection takes place in temperature gradients up to 10,000 K per meter, and density gradients of 1000% per meter and more, with rapid temperature and spatially dependent changes in physical properties like viscosity and surface tension, making software development and empirical correlations almost impossible to achieve. These temperature and density gradients are far larger than those met in other convecting systems at ambient temperatures, and there is little similarity. The paper will discuss the likely impact of CryoFD on future cryogenic systems, and hopefully inspire further research to support and expand the use of existing findings, and to improve the economy of present-day systems even more effectively. Particular examples to be mentioned include the following. Doubling the cooling power of cryo-coolers by a simple use of CryoFD. Reducing the boil-off rate of liquid helium stored at the South Pole, such that liquid helium availability is now all-the-year-round. Helping to develop the 15 kA current leads for the LHC superconducting magnets at CERN, with much reduced refrigeration loads. Improving the heat transfer capability of boiling heat transfer surfaces by 10 to 100 fold. This paper is an edited text of an invited plenary presentation at ICEC25/ICMC2014 by Professor Scurlock on the occasion of his being presented with the ICEC Mendelssohn Award for his

  7. Cryogenic systems for inertial fusion energy

    International Nuclear Information System (INIS)

    Chatain, D.; Perin, J.P.; Bonnay, P.; Bouleau, E.; Chichoux, M.; Communal, D.; Manzagol, J.; Viargues, F.; Brisset, D.; Lamaison, V.; Paquignon, G.

    2008-01-01

    The Low Temperatures Laboratory of CEA/Grenoble (France) is involved in the development of cryogenic systems for inertial fusion since a ten of years. A conceptual design for the cryogenic infrastructure of the Laser MegaJoule (LMJ) facility has been proposed. Several prototypes have been designed, built and tested like for example the 1500 bars cryo-compressor for the targets filling, the target positioner and the thermal shroud remover. The HIPER project will necessitate the development of such equipments. The main difference is that this time, the cryogenic targets are direct drive targets. The first phase of HIPER experiments is a single shot period. Based oil the experience gained the last years, not only by our laboratory but also by Omega and G.A teams, we could design the new HIPER equipments for this phase. Some experimental results obtained with the prototypes of the LMJ cryogenic system are given and a first conceptual design for the HIPER single shot cryogenic system is shown. (authors)

  8. Status of the Cryogenic Storage Ring (CSR)

    Energy Technology Data Exchange (ETDEWEB)

    Menk, Sebastian; Becker, Arno; Berg, Felix; Blaum, Klaus; Fellenberger, Florian; Froese, Michael; Goullon, Johannes; Grieser, Manfred; Krantz, Claude; Lange, Michael; Laux, Felix; Repnow, Roland; Schornikov, Andrey; Hahn, Robert von; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik (MPIK), 69117 Heidelberg (Germany); Spruck, Kaija [Institut fuer Atom- und Molekuelphysik Justus-Liebig-Universitaet, 35392 Giessen (Germany)

    2012-07-01

    A novel cryogenic storage ring is currently under construction at the MPIK. By electrostatic ion optical elements, the 35 m circumference Cryogenic Storage Ring will be able to store ions at energies of up to 300 keV per charge unit without any mass limitations. The CSR consists of a cryogenic ({proportional_to}5 K) beam pipe surrounded by two radiation shields (40 and 80 K) in a large outer, thermal insulation vacuum. Extreme vacuum (density {proportional_to}10{sup 3} cm{sup -3}) will be achieved by 2 K cryopumping as demonstrated in a prototype ion beam trap. The ion optics was completely assembled within the precision cryogenic mounting and shielding structure of the first corner. There, cooldown tests to {proportional_to}40 K were performed which confirmed the required sub-millimeter accuracy of the specially designed electrode positioning under large temperature changes. The high-voltage connections to the cryogenic electrodes were installed and breakdown tests will be reported. Based on the test results the beam pipe, electrode mounting and shielding structures are under final construction for mounting during 2012.

  9. Design and development of a device management platform for EAST cryogenic system

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Zhiwei, E-mail: zzw@ipp.ac.cn; Lu, Xiaofei, E-mail: xiaofeilu@ipp.ac.cn; Zhuang, Ming, E-mail: zhm@ipp.ac.cn; Hu, Liangbing, E-mail: huliangbing@ipp.ac.cn; Xia, Genhai, E-mail: xgh@ipp.ac.cn

    2014-05-15

    Highlights: • A device management platform for EAST cryogenic system based on DCS is designed. • This platform enhances the integrity and continuity of system device information. • It can help predictive maintenance and device management decision. - Abstract: EAST cryogenic system is one of the critical sub-systems of the EAST tokamak device. It is a large scale helium cryoplant, which adopts distributed control system to realize monitoring and control of the cryogenic process and devices. However, the maintenance and management of most field devices are still in the corrective maintenance or traditional preventive maintenance stage. Under maintained or over maintained problems widely exist, which could cause devices fault and increase operation costs. Therefore, a device management platform is proposed for a safe and steady operation as well as fault diagnosis and predictive maintenance of EAST cryogenic system. This paper presents the function design and architecture design of the cryogenic device management platform. This platform is developed based on DeltaV DCS and acquires monitoring data through OPC protocol. It consists of three pillars, namely device information management, device condition management, and device performance monitoring. The development and implementation of every pillar are illustrated in detail in this paper. Test results and discussions are presented in the end.

  10. Beginning analog electronics through projects

    CERN Document Server

    Singmin, Andrew

    2001-01-01

    Analog electronics is the simplest way to start a fun, informative, learning program. Beginning Analog Electronics Through Projects, Second Edition was written with the needs of beginning hobbyists and students in mind. This revision of Andrew Singmin's popular Beginning Electronics Through Projects provides practical exercises, building techniques, and ideas for useful electronics projects. Additionally, it features new material on analog and digital electronics, and new projects for troubleshooting test equipment.Published in the tradition of Beginning Electronics Through Projects an

  11. In-Space Cryogenic VOST Connect/Disconnect, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Two novel cryogenic couplings will be designed, fabricated and tested. Intended for in-space use at cryogenic propellant depots, the couplings are based on patented...

  12. A cryogenic test stand for full length SSC magnets with superfluid capability

    International Nuclear Information System (INIS)

    Peterson, T.J.; Mazur, P.O.

    1989-02-01

    The Fermilab Magnet Test Facility performs testing of the full scale SSC magnets on test stands capable of simulating the cryogenic environment of the SSC main ring. One of these test stands, Stand 5, also has the ability to operate the magnet under test at temperatures from 1.8K to 4.5K with either supercritical helium or subcooled liquid, providing at least 25 Watts of refrigeration. At least 50 g/s flow is available from 2.3K to 4.5K, whereas superfluid operation occurs with zero flow. Cooldown time from 4.5K to 1.8K is 1.5 hours. A maximum current capability of 10,000 amps is provided, as is instrumentation to monitor and control the cryogenic conditions. This paper describes the cryogenic design of this test stand. 8 refs., 6 figs

  13. A Low Heat Inleak Cryogenic Station for Testing HTS Current Leads for the Large Hadron Collider

    CERN Document Server

    Ballarino, A; Gomes, P; Métral, L; Serio, L; Suraci, A

    1999-01-01

    The LHC will be equipped with about 8000 superconducting magnets of all types. The total current to be transported into the cryogenic enclosure amounts to some 3360 kA. In order to reduce the heat load into the liquid helium, CERN intends to use High Temperature Superconducting (HTS) material for leads having current ratings up to 13 kA. The resistive part of the leads is cooled by forced flow of gaseous helium between 20 K and 300 K. The HTS part of the lead is immersed in a 4.5 K liquid helium bath, operates in self cooling conditions and is hydraulically separated from the resistive part. A cryogenic test station has been designed and built in order to assess the thermal and electrical performances of 13 kA prototype current leads. We report on the design, commissioning and operation of the cryogenic test station and illustrate its performance by typical test results of HTS current leads.

  14. Thermal and mechanical properties of selected 3D printed thermoplastics in the cryogenic temperature regime

    International Nuclear Information System (INIS)

    Weiss, K-P; Bagrets, N; Lange, C; Goldacker, W; Wohlgemuth, J

    2015-01-01

    Insulating materials for use in cryogenic boundary conditions are still limited to a proved selection as Polyamid, Glasfiber reinforced resins, PEEK, Vespel etc. These materials are usually formed to parts by mechanical machining or sometimes by cast methods. Shaping complex geometries in one piece is limited. Innovative 3D printing is now an upcoming revolutionary technology to construct functional parts from a couple of thermoplastic materials as ABS, Nylon and others which possess quite good mechanical stability and allow realizing very complex shapes with very subtle details. Even a wide range of material mixtures is an option and thermal treatments can be used to finish the material structure for higher performance. The use of such materials in cryogenic environment is very attractive but so far poor experience exists. In this paper, first investigations of the thermal conductivity, expansion and mechanical strength are presented for a few selected commercial 3D material samples to evaluate their application prospects in the cryogenic temperature regime. (paper)

  15. Children's Development of Analogical Reasoning: Insights from Scene Analogy Problems

    Science.gov (United States)

    Richland, Lindsey E.; Morrison, Robert G.; Holyoak, Keith J.

    2006-01-01

    We explored how relational complexity and featural distraction, as varied in scene analogy problems, affect children's analogical reasoning performance. Results with 3- and 4-year-olds, 6- and 7-year-olds, 9- to 11-year-olds, and 13- and 14-year-olds indicate that when children can identify the critical structural relations in a scene analogy…

  16. A Reference Guide for Cryogenic Properties of Materials

    Energy Technology Data Exchange (ETDEWEB)

    Weisend, John G

    2003-09-16

    A thorough knowledge of the behavior of materials at cryogenic temperatures is critical for the design of successful cryogenic systems. Over the past 50 years, a tremendous amount of material properties at cryogenic temperatures have been measured and published. This guide lists resources for finding these properties. It covers online databases, computer codes, conference proceedings, journals, handbooks, overviews and monographs. It includes references for finding reports issued by government laboratories and agencies. Most common solids and fluids used in cryogenics are covered.

  17. The Management of Cryogens at CERN

    CERN Document Server

    Delikaris, D; Passardi, Giorgio; Serio, L; Tavian, L

    2005-01-01

    CERN is a large user of industrially procured cryogens essentially liquid helium and nitrogen. Recent contracts have been placed by the Organization for the delivery of quantities up to 280 tons of liquid helium over four years and up to 50000 tons of liquid nitrogen over three years. Main users are the very large cryogenic system of the LHC accelerator complex, the physics experiments using superconducting magnets and liquefied gases and all the related test facilities whether industrial or laboratory scale. With the commissioning of LHC, the need of cryogens at CERN will considerably increase and the procurement policy must be adapted accordingly. In this paper, we discuss procurement strategy for liquid helium and nitrogen, including delivery rates, distribution methods and adopted safety standards. Global turnover, on site re-liquefaction capacity, operational consumption, accidental losses, purification means and storage capacity will be described. Finally, the short to medium term evolution of the Orga...

  18. Austenitic stainless steels with cryogenic resistance

    International Nuclear Information System (INIS)

    Tarata, Daniela Florentina

    1999-01-01

    The most used austenitic stainless steels are alloyed with chromium and nickel and have a reduced carbon content, usually lower than 0.1 % what ensures corresponding properties for processing by plastic deformation at welding, corrosion resistance in aggressive environment and toughness at low temperatures. Steels of this kind alloyed with manganese are also used to reduce the nickel content. By alloying with manganese which is a gammageneous element one ensures the stability of austenites. Being cheaper these steels may be used extensively for components and equipment used in cryogenics field. The best results were obtained with steels of second group, AMnNi, in which the designed chemical composition was achieved, i.e. the partial replacement of nickel by manganese ensured the toughness at cryogenic temperatures. If these steels are supplementary alloyed, their strength properties may increase to the detriment of plasticity and toughness, although the cryogenic character is preserved

  19. Technical presentation: BGM Cryogenic Engineering Limited

    CERN Multimedia

    Caroline Laignel - FI Department

    2006-01-01

    13 - 14 June 2006 TECHNICAL PRESENTATION BGM Cryogenic Engineering Limited 09:00 - 18:00, 60-2-016, Main Building. Presentation on BGM: 11:00 - 12:00, 60-2-016, Main Building. BGM Cryogenic Engineering Limited manufactures assemblies, sub-assemblies and machined components for the cryogenic technology sector. The primary markets served include superconducting magnets used in the healthcare sector (eg MRI body scanners), spectroscopy and NMR equipment for numerous R & D and technology applications, high vacuum applications and particle physics research. BGM has specialist assembly capability including stainless steel and aluminium welding, vacuum testing, electromechanical assembly and metal finishing. BGM offers a ‘one stop shop'facility to satisfy any customer requirement. Through our design partner we can offer a full design and modelling service, including 3D modelling and production of 2D drawings on your own borders. We can conduct heat load and force calculations and advise on the best...

  20. Designs of pulsed power cryogenic transformers

    International Nuclear Information System (INIS)

    Singh, S.K.; Heyne, C.J.; Hackowrth, D.T.; Shestak, E.J.; Eckels, P.W.; Rogers, J.D.

    1988-01-01

    The Westinghouse Electric Corporation has completed designs of three pulsed power cryogenic transformers of three pulsed power cryogenic transformers for the Los Alamos National Laboratory. These transformers will be configured to transfer their stored energy sequentially to an electro-magnetic launcher and form a three-stage power supply. The pulse transformers will act as two winding energy storage solenoids which provide a high current and energy pulse compression by transforming a 50 kA power supply into a megamp level power supply more appropriate for the electromagnetic launcher duty. This system differs from more traditional transformer applications in that significant current levels do not exists simultaneously in the two windings of the pulse transformer. This paper describes the designs of the pulsed power cryogenic transformers

  1. Cryogenic cooling system for HTS cable

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Shigeru [Taiyo Nippon Sanso, Tsukuba (Japan)

    2017-06-15

    Recently, Research and development activity of HTS (High Temperature Superconducting) power application is very progressive worldwide. Especially, HTS cable system and HTSFCL (HTS Fault current limiter) system are proceeding to practical stages. In such system and equipment, cryogenic cooling system, which makes HTS equipment cooled lower than critical temperature, is one of crucial components. In this article, cryogenic cooling system for HTS application, mainly cable, is reviewed. Cryogenic cooling system can be categorized into conduction cooling system and immersion cooling system. In practical HTS power application area, immersion cooling system with sub-cooled liquid nitrogen is preferred. The immersion cooling system is besides grouped into open cycle system and closed cycle system. Turbo-Brayton refrigerator is a key component for closed cycle system. Those two cooling systems are focused in this article. And, each design and component of the cooling system is explained.

  2. Cryogenics for Particle Accelerators and Detectors

    CERN Document Server

    Lebrun, P; Vandoni, Giovanna; Wagner, U

    2002-01-01

    Cryogenics has become a key ancillary technology of particle accelerators and detectors, contributing to their sustained development over the last fifty years. Conversely, this development has produced new challenges and markets for cryogenics, resulting in a fruitful symbiotic relation which materialized in significant technology transfer and technical progress. This began with the use of liquid hydrogen and deuterium in the targets and bubble chambers of the 1950s, 1960s and 1970s. It developed more recently with increasing amounts of liquefied noble gases - mainly argon, but also krypton and even today xenon - in calorimeters. In parallel with these applications, the availability of practical type II superconductors from the early 1960s triggered the use of superconductivity in large spectrometer magnets - mostly driven by considerations of energy savings - and the corresponding development of helium cryogenics. It is however the generalized application of superconductivity in particle accelerators - RF ac...

  3. Physics of cryogenics an ultralow temperature phenomenon

    CERN Document Server

    Zohuri, Bahman

    2018-01-01

    Physics of Cryogenics: An Ultralow Temperature Phenomenon discusses the significant number of advances that have been made during the last few years in a variety of cryocoolers, such as Brayton, Joule-Thomson, Stirling, pulse tube, Gifford-McMahon and magnetic refrigerators. The book reviews various approaches taken to improve reliability, a major driving force for new research areas. The advantages and disadvantages of different cycles are compared, and the latest improvements in each of these cryocoolers is discussed. The book starts with the thermodynamic fundamentals, followed by the definition of cryogenic and the associated science behind low temperature phenomena and properties. This book is an ideal resource for scientists, engineers and graduate and senior undergraduate students who need a better understanding of the science of cryogenics and related thermodynamics.

  4. Procedures for cryogenic X-ray ptychographic imaging of biological samples.

    Science.gov (United States)

    Yusuf, M; Zhang, F; Chen, B; Bhartiya, A; Cunnea, K; Wagner, U; Cacho-Nerin, F; Schwenke, J; Robinson, I K

    2017-03-01

    Biological sample-preparation procedures have been developed for imaging human chromosomes under cryogenic conditions. A new experimental setup, developed for imaging frozen samples using beamline I13 at Diamond Light Source, is described. This manuscript describes the equipment and experimental procedures as well as the authors' first ptychographic reconstructions using X-rays.

  5. Procedures for cryogenic X-ray ptychographic imaging of biological samples

    Directory of Open Access Journals (Sweden)

    M. Yusuf

    2017-03-01

    Full Text Available Biological sample-preparation procedures have been developed for imaging human chromosomes under cryogenic conditions. A new experimental setup, developed for imaging frozen samples using beamline I13 at Diamond Light Source, is described. This manuscript describes the equipment and experimental procedures as well as the authors' first ptychographic reconstructions using X-rays.

  6. 49 CFR 173.316 - Cryogenic liquids in cylinders.

    Science.gov (United States)

    2010-10-01

    ... filling density for hydrogen, cryogenic liquid is defined as the percent ratio of the weight of lading in... 49 Transportation 2 2010-10-01 2010-10-01 false Cryogenic liquids in cylinders. 173.316 Section... REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.316 Cryogenic liquids in...

  7. Characterization of a cryogenic ion guide at IGISOL

    NARCIS (Netherlands)

    Saastamoinen, A.; Moore, I. D.; Ranjan, M.; Dendooven, P.; Penttila, H.; Perajarvi, K.; Popov, A.; Aysto, J.

    2012-01-01

    A small volume cryogenic ion guide has been characterized at the IGISOL facility, Jyvaskyla, as a prototype to verify whether there are any major obstacles to the use of high-density cryogenic helium gas for the stopping and extraction of high-energy ions from a large volume cryogenic ion catcher.

  8. Cryogenic propulsion for lunar and Mars missions

    Science.gov (United States)

    Redd, Larry

    1988-01-01

    Future missions to the moon and Mars have been investigated with regard to propulsion system selection. The results of this analysis show that near state-of-the-art LO2/LH2 propulsion technology provides a feasible means of performing lunar missions and trans-Mars injections. In other words, existing cryogenic space engines with certain modifications and product improvements would be suitable for these missions. In addition, present day cryogenic system tankage and structural weights appear to scale reasonably when sizing for large payload and high energy missions such as sending men to Mars.

  9. Computer automation of a dilution cryogenic system

    International Nuclear Information System (INIS)

    Nogues, C.

    1992-09-01

    This study has been realized in the framework of studies on developing new technic for low temperature detectors for neutrinos and dark matter. The principles of low temperature physics and helium 4 and dilution cryostats, are first reviewed. The cryogenic system used and the technic for low temperature thermometry and regulation systems are then described. The computer automation of the dilution cryogenic system involves: numerical measurement of the parameter set (pressure, temperature, flow rate); computer assisted operating of the cryostat and the pump bench; numerical regulation of pressure and temperature; operation sequence full automation allowing the system to evolve from a state to another (temperature descent for example)

  10. Cryogenic test facility at VECC, Kolkata

    International Nuclear Information System (INIS)

    Sarkar, Amit; Bhunia, Uttam; Pradhan, J.; Sur, A.; Bhandari, R.K.; Ranganathan, R.

    2003-01-01

    In view of proposed K-500 superconducting cyclotron project, cryogenic test facility has been set up at the centre. The facility can broadly be categorized into two- a small scale test facility and a large scale test facility. This facility has been utilized for the calibration of liquid helium level probe, cryogenic temperature probe, and I-B plot for a 7 T superconducting magnet. Spiral-shaped superconducting short sample with specific dimension and specially designed stainless steel sample holder has already been developed for the electrical characterisation. The 1/5 th model superconducting coil along with its quench detection circuit and dump resistor has also been developed

  11. Compact insert design for cryogenic pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, Salvador M.; Ledesma-Orozco, Elias Rigoberto; Espinosa-Loza, Francisco; Petitpas, Guillaume; Switzer, Vernon A.

    2017-06-14

    A pressure vessel apparatus for cryogenic capable storage of hydrogen or other cryogenic gases at high pressure includes an insert with a parallel inlet duct, a perpendicular inlet duct connected to the parallel inlet. The perpendicular inlet duct and the parallel inlet duct connect the interior cavity with the external components. The insert also includes a parallel outlet duct and a perpendicular outlet duct connected to the parallel outlet duct. The perpendicular outlet duct and the parallel outlet duct connect the interior cavity with the external components.

  12. Cryogenic system for liquid hydrogen polarimeter

    International Nuclear Information System (INIS)

    Kitami, T.; Chiba, M.; Hirabayashi, H.; Ishii, T.; Kato, S.

    1979-01-01

    A cryogenic system has been constructed for a liquid hydrogen polarimeter in order to measure polarization of high energy proton at the 1.3 GeV electron synchrotron of Institute for Nuclear Study, University of Tokyo. The system principally consists of a cryogenerator with a cryogenic transfer line, a liquid hydrogen cryostat, and a 14.5 l target container of thin aluminum alloy where liquid hydrogen is served for the experiment. The refrigeration capacity is about 54 W at 20.4 K without a target container. (author)

  13. Optical analog transmission device

    International Nuclear Information System (INIS)

    Ikawa, Shinji.

    1994-01-01

    The present invention concerns a device such as electro-optical conversion elements, optoelectric-electric elements and optical transmission channel, not undergoing deleterious effects on the efficiency of conversion and transmission due to temperature, and aging change. That is, a sine wave superposing means superposes, on a detector signal to be transmitted, a sine-wave signal having a predetermined amplitude and at a frequency lower than that of the detector signal. An optoelectric conversion means converts the electric signal as the signal of the sine-wave signal superposing means into an optical signal and outputs the same to an optical transmitting channel. The optoelectric conversion means converts the transmitted signal to an electric signal. A discriminating means discriminates the electric signal into a detector signal and a sine-wave signal. A calculating means calculates an optical transmitting efficiency of the transmitting channel based on the amplitude of the discriminated sine-wave signal. A processing means compensates an amplitude value of the detector signals discriminated by the discriminating means based on the optical transmission efficiency. As a result, an optical analog transmission device can be attained, which conducts optical transmission at a high accuracy without undergoing the defective effects of the optical transmission efficiency. (I.S.)

  14. Engineered Surface Properties of Porous Tungsten from Cryogenic Machining

    Science.gov (United States)

    Schoop, Julius Malte

    Porous tungsten is used to manufacture dispenser cathodes due to it refractory properties. Surface porosity is critical to functional performance of dispenser cathodes because it allows for an impregnated ceramic compound to migrate to the emitting surface, lowering its work function. Likewise, surface roughness is important because it is necessary to ensure uniform wetting of the molten impregnate during high temperature service. Current industry practice to achieve surface roughness and surface porosity requirements involves the use of a plastic infiltrant during machining. After machining, the infiltrant is baked and the cathode pellet is impregnated. In this context, cryogenic machining is investigated as a substitutionary process for the current plastic infiltration process. Along with significant reductions in cycle time and resource use, surface quality of cryogenically machined un-infiltrated (as-sintered) porous tungsten has been shown to significantly outperform dry machining. The present study is focused on examining the relationship between machining parameters and cooling condition on the as-machined surface integrity of porous tungsten. The effects of cryogenic pre-cooling, rake angle, cutting speed, depth of cut and feed are all taken into consideration with respect to machining-induced surface morphology. Cermet and Polycrystalline diamond (PCD) cutting tools are used to develop high performance cryogenic machining of porous tungsten. Dry and pre-heated machining were investigated as a means to allow for ductile mode machining, yet severe tool-wear and undesirable smearing limited the feasibility of these approaches. By using modified PCD cutting tools, high speed machining of porous tungsten at cutting speeds up to 400 m/min is achieved for the first time. Beyond a critical speed, brittle fracture and built-up edge are eliminated as the result of a brittle to ductile transition. A model of critical chip thickness ( hc ) effects based on cutting

  15. Conjecturing via Reconceived Classical Analogy

    Science.gov (United States)

    Lee, Kyeong-Hwa; Sriraman, Bharath

    2011-01-01

    Analogical reasoning is believed to be an efficient means of problem solving and construction of knowledge during the search for and the analysis of new mathematical objects. However, there is growing concern that despite everyday usage, learners are unable to transfer analogical reasoning to learning situations. This study aims at facilitating…

  16. Musik som analogi og metafor

    DEFF Research Database (Denmark)

    Bonde, Lars Ole

    2014-01-01

    Indeholder underkapitlerne: 2.5.1 Musik som analogi 2.5.2 Musik som metafor 2.5.3 Musikkens psykologiske funktioner - en taxonomi og metaforisk lytning til fire baroksatser......Indeholder underkapitlerne: 2.5.1 Musik som analogi 2.5.2 Musik som metafor 2.5.3 Musikkens psykologiske funktioner - en taxonomi og metaforisk lytning til fire baroksatser...

  17. Drawing Analogies in Environmental Education

    Science.gov (United States)

    Affifi, Ramsey

    2014-01-01

    Reconsidering the origin, process, and outcomes of analogy-making suggests practices for environmental educators who strive to disengage humans from the isolating illusions of dichotomizing frameworks. We can view analogies as outcomes of developmental processes within which human subjectivity is but an element, threading our sense of self back…

  18. Trapping proton transfer intermediates in the disordered hydrogen-bonded network of cryogenic hydrofluoric acid solutions.

    Science.gov (United States)

    Ayotte, Patrick; Plessis, Sylvain; Marchand, Patrick

    2008-08-28

    A molecular-level description of the structural and dynamical aspects that are responsible for the weak acid behaviour of dilute hydrofluoric acid solutions and their unusual increased acidity at near equimolar concentrations continues to elude us. We address this problem by reporting reflection-absorption infrared spectra (RAIRS) of cryogenic HF-H(2)O binary mixtures at various compositions prepared as nanoscopic films using molecular beam techniques. Optical constants for these cryogenic solutions [n(omega) and k(omega)] are obtained by iteratively solving Fresnel equations for stratified media. Modeling of the experimental RAIRS spectra allow for a quantitative interpretation of the complex interplay between multiple reflections, optical interference and absorption effects. The evolution of the strong absorption features in the intermediate 1000-3000 cm(-1) range with increasing HF concentration reveals the presence of various ionic dissociation intermediates that are trapped in the disordered H-bonded network of cryogenic hydrofluoric acid solutions. Our findings are discussed in light of the conventional interpretation of why hydrofluoric acid is a weak acid revealing molecular-level details of the mechanism for HF ionization that may be relevant to analogous elementary processes involved in the ionization of weak acids in aqueous solutions.

  19. Dynamic simulations of the cryogenic system of a tokamak

    International Nuclear Information System (INIS)

    Cirillo, R.; Hoa, C.; Michel, F.; Rousset, B.; Poncet, J.M.

    2015-01-01

    In a tokamak plasma confinement is achieved through high magnetic fields generated by superconductive coils that need to be cooled down to 4.4 K with a forced flow of supercritical Helium. Tokamak's coil system works cyclically and so it is subject to pulsed heat loads which have to be handled by the refrigerator. This latter has to be sized on the average power value and not according to the peak to limit investment and operation costs and hence the heat load needs to be smoothed. CEA Grenoble is in charge of providing the cryogenic system for the Japanese tokamak JT60-SA, currently under construction in Naka (Japan). Hence, in order to model and study the smoothing strategies, an experimental set up: HELIOS (Helium Loop for high load smoothing) has been built. This is a scaled down model (1:20) of the helium distribution system whose main components are a saturated helium bath and a supercritical helium loop. This large installation can reproduce conditions of pressure, temperature and transport times, similar to those expected in the cooling circuits of the central solenoid superconducting magnets of JT-60SA. The peak loads representative of the tokamak operation have been reproduced and smoothed before they arrive in the refrigerator, by means of a saturated helium bath (thermal reservoir). A dynamic modelling of the cryogenic system is presented, with results on the pulsed load scenarios. All the simulations have been performed with EcosimPro software developed and the cryogenic library: CRYOLIB. This document is made up of an abstract and the slides of the presentation

  20. Operational and troubleshooting experiences in the SST-1 cryogenic system

    Science.gov (United States)

    Mahesuria, G.; Panchal, P.; Panchal, R.; Patel, R.; Sonara, D.; Gupta, N. C.; Srikanth, G. L. N.; Christian, D.; Garg, A.; Bairagi, N.; Patel, K.; Shah, P.; Nimavat, H.; Sharma, R.; Patel, J. C.; Tank, J.; Tanna, V. L.; Pradhan, S.

    2014-01-01

    Recently, the cooldown and current charging campaign have been carried out towards the demonstration of the first successful plasma discharge in the steady state superconducting Tokomak (SST-1). The SST-1 machine consists of cable-in-conduit wound superconducting toroidal as well as poloidal coils, cooled using 1.3 kW at 4.5 K helium refrigerator -cum- liquefier (HRL) system. The cryo system provides the two-phase helium at 0.13 MPa at 4.5 K as well as forced-flow pressurized helium at 0.4 MPa and in addition to 7 g-s-1 liquefaction capacity required for the current leads and other cold mass at 4.5 K. The entire integrated cold masses having different thermo hydraulic resistances cooled with the SST-1 HRL in optimised process parameters. In order to maintain different levels of temperatures and to facilitate smooth and reliable cooldown, warm-up, normal operations as well as to handle abnormal events such as, quench or utilities failures etc., exergy efficient process are adopted for the helium refrigerator-cum-liquefier (HRL) with an installed equivalent capacity of 1.3 kW at 4.5 K. Using the HRL, the cold mass of about 40 tons is being routinely cooled down from ambient temperature to 4.5 K with an average cooldown rate of 0.75 - 1 K-h-1. Long-term cryogenic stable conditions were obtained within 15 days in the superconducting coils and their connecting feeders. Afterwards, all of the cold mass is warmed-up in a controlled manner to ambient temperature. In this paper, we report the recent operational results of the cryogenic system during the first plasma discharge in SST-1 as well as the troubleshooting experiences of the cryogenic plant related hardware.

  1. Studies on cryogenic distillation columns for hydrogen isotope separation

    International Nuclear Information System (INIS)

    Kinoshita, Masahiro

    1984-08-01

    Cryogenic distillation is applicable to a number of situations. The feed condition, column cascade configuration, input and output specifications vary greatly from situation to situation. In the mainstream fuel circulation system for a fusion reactor, the feed composition may fluctuate greatly during the operation. The radiological standards for tritium lost to the environment are increasingly becoming stricter. Systematic studies are needed to achieve the goal of long-term operation meeting the strict requirements for products even under great fluctuation of the feed condition in all the situations. The present report gives a critical, brief review of the studies which have been made by the author. The subjects treated are development of computer simulation procedures, analysis on an H-T separation column with a feedback stream, dynamics and control, proposal of a new cascade, analysis on helium effects on column behavior, start-up analysis for a cascade, and preliminary experimental study on dependence of HETP on operational conditions. (author)

  2. Multiresponse optimization of cryogenic drilling on Ti-6Al-4V alloy using topsis method

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, L. Shakeel; Kumar, M. Pradeep [Anna University, Chennai (India)

    2016-04-15

    Multiresponse optimization of process parameters in drilling is focused in this article using the TOPSIS technique to obtain minimum cutting temperature (T), thrust force (Ft), torque (Mt) and surface roughness (Ra), Circularity (Cir), Cylindricity (Cyl). The experiments were performed on Titanium alloy Ti-6Al-4V in different cooling environments: Wet cooling and cryogenic cooling conditions. Liquid nitrogen (LN{sub 2} ) as a coolant is used in cryogenic machining. The control factors selected were machining environments, cutting speed (Vc) and feed rate (f). Eighteen experiments were conducted in wet and cryogenic LN2 conditions based on L{sub 1}8 orthogonal array, respectively. The optimization results indicate drilling at V{sub c} = 40 m/min and f = 0.02 mm/rev which is of the lowest value in cryogenic LN{sub 2} condition. A better performance is achieved too. The optimum multiresponses show that TOPSIS method is the most effective performance in the drilling process.

  3. CRYOGENIC AND VACUUM TECHNOLOGICAL ASPECTS OF THE LOW-ENERGY ELECTROSTATIC CRYOGENIC STORAGE RING

    International Nuclear Information System (INIS)

    Orlov, D. A.; Lange, M.; Froese, M.; Hahn, R. von; Grieser, M.; Mallinger, V.; Sieber, T.; Weber, T.; Wolf, A.; Rappaport, M.

    2008-01-01

    The cryogenic and vacuum concepts for the electrostatic Cryogenic ion Storage Ring (CSR), under construction at the Max-Planck-Institut fuer Kernphysik in Heidelberg, is presented. The ring will operate in a broad temperature range from 2 to 300 K and is required to be bakeable up to 600 K. Extremely high vacuum and low temperatures are necessary to achieve long lifetimes of the molecular ions stored in the ring so that the ions will have enough time to cool by radiation to their vibrational and rotational ground states. To test cryogenic and vacuum technological aspects of the CSR, a prototype is being built and will be connected to the commercial cryogenic refrigerator recently installed, including a specialized 2-K connection system. The first results and the status of current work with the prototype are also presented

  4. Generating explanations via analogical comparison.

    Science.gov (United States)

    Hoyos, Christian; Gentner, Dedre

    2017-10-01

    Generating explanations can be highly effective in promoting learning in both adults and children. Our interest is in the mechanisms that underlie this effect and in whether and how they operate in early learning. In adult reasoning, explanation may call on many subprocesses-including comparison, counterfactual reasoning, and reasoning by exclusion; but it is unlikely that all these processes are available to young children. We propose that one process that may serve both children and adults is comparison. In this study, we asked whether children would use the results of a comparison experience when asked to explain why a model skyscraper was stable. We focused on a challenging principle-that diagonal cross-bracing lends stability to physical structures (Gentner et al., Cognitive Science, 40, 224-240, 2016). Six-year-olds either received no training or interacted with model skyscrapers in one of three different conditions, designed to vary in their potential to invite and support comparison. In the Single Model condition, children interacted with a single braced model. In the comparison conditions (Low Alignability and High Alignability), children compared braced and unbraced models. Following experience with the models, children were asked to explain why the braced model was stable. They then received two transfer tasks. We found that children who received highly alignable pairs were most likely to (a) produce brace-based explanations and (b) transfer the brace principle to a dissimilar context. This provides evidence that children can benefit from analogical comparison in generating explanations and also suggests limitations on this ability.

  5. Impact resistance cryogenic bunker fuel tanks

    NARCIS (Netherlands)

    Voormeeren, L.O.; Atli-Veltin, B.; Vredeveldt, A.W.

    2014-01-01

    The increasing use of liquefied natural gas (LNG) as bunker fuel in ships, calls for an elaborate study regarding the risks involved. One particular issue is the vulnerability of cryogenic LNG storage tanks with respect to impact loadings, such as ship collisions and dropped objects. This requires

  6. The Cryogenic Test Bed experiments: Cryogenic heat pipe flight experiment CRYOHP (STS-53). Cryogenic two phase flight experiment CRYOTP (STS-62). Cryogenic flexible diode flight experiment CRYOFD

    Science.gov (United States)

    Thienel, Lee; Stouffer, Chuck

    1995-09-01

    This paper presents an overview of the Cryogenic Test Bed (CTB) experiments including experiment results, integration techniques used, and lessons learned during integration, test and flight phases of the Cryogenic Heat Pipe Flight Experiment (STS-53) and the Cryogenic Two Phase Flight Experiment (OAST-2, STS-62). We will also discuss the Cryogenic Flexible Diode Heat Pipe (CRYOFD) experiment which will fly in the 1996/97 time frame and the fourth flight of the CTB which will fly in the 1997/98 time frame. The two missions tested two oxygen axially grooved heat pipes, a nitrogen fibrous wick heat pipe and a 2-methylpentane phase change material thermal storage unit. Techniques were found for solving problems with vibration from the cryo-collers transmitted through the compressors and the cold heads, and mounting the heat pipe without introducing parasitic heat leaks. A thermally conductive interface material was selected that would meet the requirements and perform over the temperature range of 55 to 300 K. Problems are discussed with the bi-metallic thermostats used for heater circuit protection and the S-Glass suspension straps originally used to secure the BETSU PCM in the CRYOTP mission. Flight results will be compared to 1-g test results and differences will be discussed.

  7. Nuclear heat sources for cryogenic refrigerator applications

    International Nuclear Information System (INIS)

    Raab, B.; Schock, A.; King, W.G.; Kline, T.; Russo, F.A.

    1975-01-01

    Spacecraft cryogenic refrigerators require thermal inputs on the order of 1000 W. First, the characteristics of solar-electric and radioisotope heat source systems for supplying this thermal input are compared. Then the design of a 238 Pu heat source for this application is described, and equipment for shipping and handling the heat source is discussed. (LCL)

  8. Cryogenic Heat Exchanger with Turbulent Flows

    Science.gov (United States)

    Amrit, Jay; Douay, Christelle; Dubois, Francis; Defresne, Gerard

    2012-01-01

    An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N[subscript 2] and He gases from room temperatures. We present first the experimental results of…

  9. Cryogenic testing of the TPC superconducting solenoid

    International Nuclear Information System (INIS)

    Green, M.A.; Smits, R.G.; Taylor, J.D.

    1983-06-01

    This report describes the results of a series of tests on the TPC superconducting magnet cryogenic system which occurred during the winter and spring of 1983. The tests occurred at interaction region 2 of the PEP colliding beam facility at the Stanford Linear Accelerator Center (SLAC). The TPC Magnet Cryogenic System which was tested includes the following major components: a remote helium compressor with a full flow liquid nitrogen purification station, 400 meters of high pressure supply and low pressure return lines; and locally a CTi Model 2800 refrigerator with two Sulzer gas bearing turbines, the TPC magnet control dewar, 70 meters of transfer lines, and the TPC thin superconducting solenoid magnet. In addition, there is a conditioner (liquid nitrogen heat exchangers and gas heaters) system for cooldown and warmup of the magnet. This report describes the local cryogenic system and describes the various steps in the cooldown and operation of the TPC magnet. The tests were successful in that they showed that the TPC magnet could be cooled down in 24 hours and the magnet could be operated on the refrigerator or a helium pump with adequate cooling margin. The tests identified problems with the cryogenic system and the 2800 refrigerator. Procedures for successful operation and quenching of the superconducting magnet were developed. 19 references

  10. Comparison of cryogenic low-pass filters

    Science.gov (United States)

    Thalmann, M.; Pernau, H.-F.; Strunk, C.; Scheer, E.; Pietsch, T.

    2017-11-01

    Low-temperature electronic transport measurements with high energy resolution require both effective low-pass filtering of high-frequency input noise and an optimized thermalization of the electronic system of the experiment. In recent years, elaborate filter designs have been developed for cryogenic low-level measurements, driven by the growing interest in fundamental quantum-physical phenomena at energy scales corresponding to temperatures in the few millikelvin regime. However, a single filter concept is often insufficient to thermalize the electronic system to the cryogenic bath and eliminate spurious high frequency noise. Moreover, the available concepts often provide inadequate filtering to operate at temperatures below 10 mK, which are routinely available now in dilution cryogenic systems. Herein we provide a comprehensive analysis of commonly used filter types, introduce a novel compact filter type based on ferrite compounds optimized for the frequency range above 20 GHz, and develop an improved filtering scheme providing adaptable broad-band low-pass characteristic for cryogenic low-level and quantum measurement applications at temperatures down to few millikelvin.

  11. Comparison of cryogenic low-pass filters.

    Science.gov (United States)

    Thalmann, M; Pernau, H-F; Strunk, C; Scheer, E; Pietsch, T

    2017-11-01

    Low-temperature electronic transport measurements with high energy resolution require both effective low-pass filtering of high-frequency input noise and an optimized thermalization of the electronic system of the experiment. In recent years, elaborate filter designs have been developed for cryogenic low-level measurements, driven by the growing interest in fundamental quantum-physical phenomena at energy scales corresponding to temperatures in the few millikelvin regime. However, a single filter concept is often insufficient to thermalize the electronic system to the cryogenic bath and eliminate spurious high frequency noise. Moreover, the available concepts often provide inadequate filtering to operate at temperatures below 10 mK, which are routinely available now in dilution cryogenic systems. Herein we provide a comprehensive analysis of commonly used filter types, introduce a novel compact filter type based on ferrite compounds optimized for the frequency range above 20 GHz, and develop an improved filtering scheme providing adaptable broad-band low-pass characteristic for cryogenic low-level and quantum measurement applications at temperatures down to few millikelvin.

  12. Cryogenic refrigeration for cold neutron sources

    International Nuclear Information System (INIS)

    Gistau-Baguer, Guy

    1998-01-01

    Neutron moderation by means of a fluid at cryogenic temperature is a very interesting way to obtain cold neutrons. Today, a number of nuclear research reactors are using this technology. This paper deals with thermodynamics and technology which are used for cooling Cold Neutron Sources

  13. Cryogenic Fuel Tank Draining Analysis Model

    Science.gov (United States)

    Greer, Donald

    1999-01-01

    One of the technological challenges in designing advanced hypersonic aircraft and the next generation of spacecraft is developing reusable flight-weight cryogenic fuel tanks. As an aid in the design and analysis of these cryogenic tanks, a computational fluid dynamics (CFD) model has been developed specifically for the analysis of flow in a cryogenic fuel tank. This model employs the full set of Navier-Stokes equations, except that viscous dissipation is neglected in the energy equation. An explicit finite difference technique in two-dimensional generalized coordinates, approximated to second-order accuracy in both space and time is used. The stiffness resulting from the low Mach number is resolved by using artificial compressibility. The model simulates the transient, two-dimensional draining of a fuel tank cross section. To calculate the slosh wave dynamics the interface between the ullage gas and liquid fuel is modeled as a free surface. Then, experimental data for free convection inside a horizontal cylinder are compared with model results. Finally, cryogenic tank draining calculations are performed with three different wall heat fluxes to demonstrate the effect of wall heat flux on the internal tank flow field.

  14. Cryogenic Filters for RFI Mitigation in Radioastronomy

    OpenAIRE

    Tuccari, G.; Caddemi, A.; Barbarino, S.; Nicotra, G.; Consoli, F.; Schilliro, F.; Catalfamo, F.

    2005-01-01

    RFI mitigation in Radioastronomy can be achieved adopting cryogenic filters in appropriate typologies. A study has been conducted in L, C and X band with the evaluation of the filter architecture in copper, with theoretical estimation, computer simulations, prototypes realization, laboratory measurements. Such work has been preliminary to the realization of HTS samples with the purpose of a similar complete characterization approach.

  15. Cryogenics Testbed Laboratory Flange Baseline Configuration

    Science.gov (United States)

    Acuna, Marie Lei Ysabel D.

    2013-01-01

    As an intern at Kennedy Space Center (KSC), I was involved in research for the Fluids and Propulsion Division of the NASA Engineering (NE) Directorate. I was immersed in the Integrated Ground Operations Demonstration Units (IGODU) project for the majority of my time at KSC, primarily with the Ground Operations Demonstration Unit Liquid Oxygen (GODU L02) branch of IGODU. This project was established to develop advancements in cryogenic systems as a part of KSC's Advanced Exploration Systems (AES) program. The vision of AES is to develop new approaches for human exploration, and operations in and beyond low Earth orbit. Advanced cryogenic systems are crucial to minimize the consumable losses of cryogenic propellants, develop higher performance launch vehicles, and decrease operations cost for future launch programs. During my internship, I conducted a flange torque tracking study that established a baseline configuration for the flanges in the Simulated Propellant Loading System (SPLS) at the KSC Cryogenics Test Laboratory (CTL) - the testing environment for GODU L02.

  16. Cryogenic Liquid Fluctuations in a Motionless Tank

    Directory of Open Access Journals (Sweden)

    Min Vin Ai

    2014-01-01

    Full Text Available The article considers approximate numerical methods to determine own frequencies of cryogenic liquid fluctuations stratification of which changes under any law. The increasing use of cryogenic liquids, liquefied gas, superfluid solutions, and slush liquids in modern mechanical engineering define relevance of a perspective. Interest in the considered problem is also caused by the fact that in cryogenic liquid along with superficial waves there can be internal wave movements penetrating all thickness of liquid in a tank and therefore playing important role in many hydro-dynamic processes.This article considers problems of determining the own frequencies of cryogenic liquid fluctuations, partially filling cylindrical tank of any cross section. It is supposed that the change of the liquid particles density due to thermal stratification of entire liquid mass can proceed continuously under any law. To solve numerically a similar problem, a method of trigonometric series (MTS and a method of final elements (MFE were used. When using the MTS method the unknown solution and variable coefficients of the equation were presented in the form of trigonometric series. Further, after multiplication of series and the subsequent mathematical operations the frequency equation was obtained. Bubnov-Galyorkin's approach was used to obtain solutions by the MFE method. Reliability of received numerical results is confirmed by coincidence with frequency results calculated by analytical formulas of solutions of differential equations with constant frequency of buoyancy.

  17. Cryogenics system: strategy to achieve nominal performance and reliable operation

    CERN Document Server

    Bremer, J; Casas, J; Claudet, S; Delikaris, D; Delruelle, N; Ferlin, G; Fluder, C; Perin, A; Perinic, G; Pezzetti, M; Pirotte, O; Tavian, L; Wagner, U

    2012-01-01

    During the LHC operation in 2010 and 2011, the cryogenic system has achieved an availability level fulfilling the overall requirement. To reach this level, the cryogenic system has profited like many other beam-dependent systems from the reduced beam parameters. Therefore, impacts of some failures occurred during the LHC operation were mitigated by using the overcapacity margin, the existing built-in redundancy in between adjacent sector cryogenic plants and the "cannibalization" of spares on two idle cryogenic plants. These two first years of operation were also crucial to identify the weaknesses of the present cryogenic maintenance plan and new issues like SEUs. After the LS1, nominal beam parameters are expected and the mitigated measures will be less effective or not applicable at all. Consequently, a consolidation plan to improve the MTBF and the MTTR of the LHC cryogenic system is under definition. Concerning shutdown periods, the present cryogenic sectorization imposes some restrictions in the type of ...

  18. Analog fourier transform channelizer and OFDM receiver

    OpenAIRE

    2007-01-01

    An OFDM receiver having an analog multiplier based I-Q channelizing filter, samples and holds consecutive analog I-Q samples of an I-Q baseband, the I-Q basebands having OFDM sub-channels. A lattice of analog I-Q multipliers and analog I-Q summers concurrently receives the held analog I-Q samples, performs analog I-Q multiplications and analog I-Q additions to concurrently generate a plurality of analog I-Q output signals, representing an N-point discrete Fourier transform of the held analog ...

  19. Cryogenic hydrogen fuel for controlled inertial confinement fusion (formation of reactor-scale cryogenic targets)

    Energy Technology Data Exchange (ETDEWEB)

    Aleksandrova, I. V.; Koresheva, E. R., E-mail: elena.koresheva@gmail.com; Krokhin, O. N. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Osipov, I. E. [Power Efficiency Centre, Inter RAO UES (Russian Federation)

    2016-12-15

    In inertial fusion energy research, considerable attention has recently been focused on low-cost fabrication of a large number of targets by developing a specialized layering module of repeatable operation. The targets must be free-standing, or unmounted. Therefore, the development of a target factory for inertial confinement fusion (ICF) is based on methods that can ensure a cost-effective target production with high repeatability. Minimization of the amount of tritium (i.e., minimization of time and space at all production stages) is a necessary condition as well. Additionally, the cryogenic hydrogen fuel inside the targets must have a structure (ultrafine layers—the grain size should be scaled back to the nanometer range) that supports the fuel layer survivability under target injection and transport through the reactor chamber. To meet the above requirements, significant progress has been made at the Lebedev Physical Institute (LPI) in the technology developed on the basis of rapid fuel layering inside moving free-standing targets (FST), also referred to as the FST layering method. Owing to the research carried out at LPI, unique experience has been gained in the development of the FST-layering module for target fabrication with an ultrafine fuel layer, including a reactor- scale target design. This experience can be used for the development of the next-generation FST-layering module for construction of a prototype of a target factory for power laser facilities and inertial fusion power plants.

  20. Upgrade to the Cryogenic Hydrogen Gas Target Monitoring System

    Science.gov (United States)

    Slater, Michael; Tribble, Robert

    2013-10-01

    The cryogenic hydrogen gas target at Texas A&M is a vital component for creating a secondary radioactive beam that is then used in experiments in the Momentum Achromat Recoil Spectrometer (MARS). A stable beam from the K500 superconducting cyclotron enters the gas cell and some incident particles are transmuted by a nuclear reaction into a radioactive beam, which are separated from the primary beam and used in MARS experiments. The pressure in the target chamber is monitored so that a predictable isotope production rate can be assured. A ``black box'' received the analog pressure data and sent RS232 serial data through an outdated serial connection to an outdated Visual Basic 6 (VB6) program, which plotted the chamber pressure continuously. The black box has been upgraded to an Arduino UNO microcontroller [Atmel Inc.], which can receive the pressure data and output via USB to a computer. It has been programmed to also accept temperature data for future upgrade. A new computer program, with updated capabilities, has been written in Python. The software can send email alerts, create audible alarms through the Arduino, and plot pressure and temperature. The program has been designed to better fit the needs of the users. Funded by DOE and NSF-REU Program.

  1. Molecular modeling of fentanyl analogs

    Directory of Open Access Journals (Sweden)

    LJILJANA DOSEN-MICOVIC

    2004-11-01

    Full Text Available Fentanyl is a highly potent and clinically widely used narcotic analgesic. A large number of its analogs have been synthesized, some of which (sufentanil and alfentanyl are also in clinical use. Theoretical studies, in recent years, afforded a better understanding of the structure-activity relationships of this class of opiates and allowed insight into the molecular mechanism of the interactions of fentanyl analogs with their receptors. An overview of the current computational techniques for modeling fentanyl analogs, their receptors and ligand-receptor interactions is presented in this paper.

  2. Gemini analogs of vitamin D.

    Science.gov (United States)

    Pazos, Gonzalo; Rivadulla, Marcos L; Pérez-García, Xenxo; Gandara, Zoila; Pérez, Manuel

    2014-01-01

    The Gemini analogs are the last significant contribution to the family of vitamin D derivatives in medicine, for the treatment of cancer. The first Gemini analog was characterized by two symmetric side chains at C-20. Following numerous modifications, the most active analog bears a C-23-triple bond, C-26, 27- hexafluoro substituents on one side chain and a terminal trideuteromethylhydroxy group on the other side chain. This progression was possible due to improvements in the synthetic methods for the preparation of these derivatives, which allowed for increasing molecular complexity and complete diastereoselective control at C-20 and the substituted sidechains.

  3. Analogy as a means of theoretical adoption of pedagogical disciplines

    Directory of Open Access Journals (Sweden)

    Solovcova Irina A.

    2006-01-01

    Full Text Available The paper considers an application of analogy in the initial-teacher training as a tool of approaching pedagogical disciplines. The author proposes a classification of pedagogical analogies which provides choices of the most efficient model for a specific didactic situation. The article clarifies the model of the theoretical approach to pedagogical disciplines through active use of analogy, which contributes to a higher efficiency in a teacher and student interaction. The model consists of three stages: training (the stage of acquiring analogy model, the analytical stage (acquisition of pedagogical concepts, phenomena and systems through the application of analogy, and the stage of self-realization (the application of analogy method in students’ scientific-research activities considering external and internal didactic conditions which transform analogy from a teaching method into a tool for the acquisition of pedagogical disciplines. The author demonstrates that the application of analogy has a positive effect not only on the acquisition of pedagogical knowledge (especially methodic and the development of heuristic skills in students, but also on motivation for the study of pedagogical disciplines (cognitive aspect and professional pedagogical activity (formation of an individual-pedagogical attitude. .

  4. Optimization of light collection from crystal scintillators for cryogenic experiments

    International Nuclear Information System (INIS)

    Mokina, V.M.; Danevich, F.A.; Kobychev, V.V.; Kraus, H.; Mikhailik, V.B.; Nagornaya, L.L.

    2012-01-01

    Cryogenic scintillation bolometers are a promising technique to search for dark matter and neutrinoless double decay. Improvement of light collection and energy resolution are important requirements in such experiments. Energy resolutions and relative pulse amplitudes of scintillation detectors using ZnWO 4 scintillation crystals of different shapes (cylinder 20x20 mm and hexagonal prism with diagonal 20 mm and height 20 mm), reflector materials and shapes, optical contact and surface properties (polished and diffused) were measured. The crystal scintillator of hexagonal shape shows the better energy resolution and pulse amplitude. The best energy resolution (FWHM = 9.3 % for 662 keV γ quanta of 137 Cs) was obtained with a hexagonal scintillator with all surfaces diffuse, in optical contact with a PMT and surrounded by a reflector (3M) of size 26x25 mm. In the geometry w ithout optical contact r epresenting the conditions of light collection for a cryogenic scintillating bolometer the best energy resolution and relative pulse amplitude was obtained for a hexagonal shape scintillator with diffuse side and polished face surfaces, surrounded by a reflector with a gap between the scintillator and the reflector

  5. Cryogenic system for the 45 Tesla hybrid magnet

    International Nuclear Information System (INIS)

    Van Sciver, S.W.; Miller, J.R.; Welton, S.; Schneider-Muntau, H.J.; McIntosh, G.E.

    1994-01-01

    The 45 Tesla hybrid magnet system will consist of a 14 Tesla superconducting outsert magnet and a 31 Tesla water cooled insert. The magnet is planned for operation in early 1995 at the National High Magnetic Field Laboratory. Its purpose is to provide the highest DC magnetic fields for the materials research community. The present paper discusses the overall design of the cryogenic system for the superconducting magnet. Unique features of this system include static 1.8 K pressurized He II as a coolant for the magnet and a refrigerated structural support system for load transfer during fault conditions. The system will consist of two connected cryostats. The magnet is contained within one cryostat which has a clear warm bore of 616 mm and is designed to be free of system interfaces and therefore minimize interference with the magnet user. A second supply cryostat provides the connections to the refrigeration system and magnet power supply. The magnet and supply cryostats are connected to each other through a horizontal services duct section. Issues to be discussed in the present paper include design and thermal analysis of the magnet system during cooldown and in steady state operation and overall cryogenic system design

  6. Cryotribology: Development of cryotribological theories and application to cryogenic devices

    Energy Technology Data Exchange (ETDEWEB)

    Iwasa, Y.; Michael, P. (Massachusetts Inst. of Tech., Cambridge, MA (United States)); Rabinowicz, E. (Massachusetts Inst. of Tech., Cambridge, MA (United States) Massachusetts Inst. of Tech., Cambridge, MA (United States). Francis Bitter National Magnet Lab.)

    1992-09-15

    High-performance superconducting solenoids are susceptible to premature quenches, or superconducting to normal state transitions, due to abrupt conductor movements within the winding. Abrupt motions involving 5{approximately}10{mu}m conductor displacements dissipate sufficient energy to trigger a quench. Sliding and mechanical behaviors of materials at cryogenic temperatures have been experimentally examined. After accounting for changes in the sliding materials' low-temperature strength properties, we have found that the adhesion theory of friction and wear remains applicable at cryogenic temperatures. The adhesion friction theory suggests two methods for controlling unsteady sliding motions. The first involves the selection of sliding materials whose friction coefficients increase with increasing sliding speed. A number of material pairs have been examined for positive friction-velocity characteristics. This materials-based approach to frictional stabilization does not seem a viable option at 4.2 K. The second altemative is to preprogram the force conditions within high-risk regions of the winding to regulate the occurrence of unsteady sliding motions. Structural models are proposed to account for unsteady conductor motions on a variety of dimensional scales. The models are used to design a small superconducting solenoid. Performance of this solenoid suggests that force-based motion control is a potentially viable design approach for achieving successful dry-wound magnets.

  7. Targeting thyroid diseases with TSH receptor analogs.

    Science.gov (United States)

    Galofré, Juan C; Chacón, Ana M; Latif, Rauf

    2013-12-01

    The thyroid-stimulating hormone (TSH) receptor (TSHR) is a major regulator of thyroid function and growth, and is the key antigen in several pathological conditions including hyperthyroidism, hypothyroidism, and thyroid tumors. Various effective treatment strategies are currently available for many of these clinical conditions such as antithyroid drugs or radioiodine therapy, but they are not devoid of side effects. In addition, treatment of complications of Graves' disease such as Graves' ophthalmopathy is often difficult and unsatisfactory using current methods. Recent advances in basic research on both in vitro and in vivo models have suggested that TSH analogs could be used for diagnosis and treatment of some of the thyroid diseases. The advent of high-throughput screening methods has resulted in a group of TSH analogs called small molecules, which have the potential to be developed as promising drugs. Small molecules are low molecular weight compounds with agonist, antagonist and, in some cases, inverse agonist activity on TSHR. This short review will focus on current advances in development of TSH analogs and their potential clinical applications. Rapid advances in this field may lead to the conduct of clinical trials of small molecules related to TSHR for the management of Graves' disease, thyroid cancer, and thyroid-related osteoporosis in the coming years. Copyright © 2012 SEEN. Published by Elsevier Espana. All rights reserved.

  8. Analog filters in nanometer CMOS

    CERN Document Server

    Uhrmann, Heimo; Zimmermann, Horst

    2014-01-01

    Starting from the basics of analog filters and the poor transistor characteristics in nanometer CMOS 10 high-performance analog filters developed by the authors in 120 nm and 65 nm CMOS are described extensively. Among them are gm-C filters, current-mode filters, and active filters for system-on-chip realization for Bluetooth, WCDMA, UWB, DVB-H, and LTE applications. For the active filters several operational amplifier designs are described. The book, furthermore, contains a review of the newest state of research on low-voltage low-power analog filters. To cover the topic of the book comprehensively, linearization issues and measurement methods for the characterization of advanced analog filters are introduced in addition. Numerous elaborate illustrations promote an easy comprehension. This book will be of value to engineers and researchers in industry as well as scientists and Ph.D students at universities. The book is also recommendable to graduate students specializing on nanoelectronics, microelectronics ...

  9. Analog elements for transuranic chemistries

    International Nuclear Information System (INIS)

    Weimer, W.C.

    1982-01-01

    The analytical technique for measuring trace concentrations of the analog rare earth elements has been refined for optimal detection. The technique has been used to determine the rare earth concentrations in a series of geological and biological materials, including samples harvested from controlled lysimeter investigations. These studies have demonstrated that any of the trivalent rare earth elements may be used as analog elements for the trivalent transuranics, americium and curium

  10. CMOS Analog IC Design: Fundamentals

    OpenAIRE

    Bruun, Erik

    2018-01-01

    This book is intended for use as the main textbook for an introductory course in CMOS analog integrated circuit design. It is aimed at electronics engineering students who have followed basic courses in mathematics, physics, circuit theory, electronics and signal processing. It takes the students directly from a basic level to a level where they can start working on simple analog IC design projects or continue their studies using more advanced textbooks in the field. A distinct feature of thi...

  11. Analogical Arguments in Ethics and Law: A Defence of Deductivism

    Directory of Open Access Journals (Sweden)

    Fábio Perin Shecaira

    2013-09-01

    Full Text Available The paper provides a qualified defence of Bruce Waller’s deductivist schema for a priori analogical arguments in ethics and law. One crucial qualification is that the schema represents analogical arguments as complexes composed of one deductive inference (hence “deductivism” but also of one non-deductive subargument. Another important qualification is that the schema is informed by normative assumptions regarding the conditions that an analogical argument must satisfy in order for it to count as an optimal instance of its kind. Waller’s schema (in qualified form is defended from criticisms formulated by Trudy Govier, Marcello Guarini and Lilian Bermejo-Luque.

  12. Analogical proportions: another logical view

    Science.gov (United States)

    Prade, Henri; Richard, Gilles

    This paper investigates the logical formalization of a restricted form of analogical reasoning based on analogical proportions, i.e. statements of the form a is to b as c is to d. Starting from a naive set theoretic interpretation, we highlight the existence of two noticeable companion proportions: one states that a is to b the converse of what c is to d (reverse analogy), while the other called paralogical proportion expresses that what a and b have in common, c and d have it also. We identify the characteristic postulates of the three types of proportions and examine their consequences from an abstract viewpoint. We further study the properties of the set theoretic interpretation and of the Boolean logic interpretation, and we provide another light on the understanding of the role of permutations in the modeling of the three types of proportions. Finally, we address the use of these proportions as a basis for inference in a propositional setting, and relate it to more general schemes of analogical reasoning. The differences between analogy, reverse-analogy, and paralogy is still emphasized in a three-valued setting, which is also briefly presented.

  13. Software approach to automatic patching of analog computer

    Science.gov (United States)

    1973-01-01

    The Automatic Patching Verification program (APV) is described which provides the hybrid computer programmer with a convenient method of performing a static check of the analog portion of his study. The static check insures that the program is patched as specified, and that the computing components being used are operating correctly. The APV language the programmer uses to specify his conditions and interconnections is similar to the FORTRAN language in syntax. The APV control program reads APV source program statements from an assigned input device. Each source program statement is processed immediately after it is read. A statement may select an analog console, set an analog mode, set a potentiometer or DAC, or read from the analog console and perform a test. Statements are read and processed sequentially. If an error condition is detected, an output occurs on an assigned output device. When an end statement is read, the test is terminated.

  14. Assembly for the deformation by drawing in cryogenic conditions

    International Nuclear Information System (INIS)

    Volchok, O.I.; Dmitrenko, L.I.; Yaes, N.A.

    2003-01-01

    Design of the assembly for the drawing in liquid nitrogen is described. Such a design ensures the tensor recording of drawing force, the wire arrangement on the drawing force dram, the drawing realization with the linear ultrasonic (f approx 20 kHz) mechanical vibrations superposition. The comparative data of some material samples physical-mechanical properties are presented. The presented data demonstrate the low temperature deformation efficiency

  15. Ion irradiation damage in ilmenite under cryogenic conditions

    International Nuclear Information System (INIS)

    Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.

    1996-01-01

    A natural single crystal of ilmenite was irradiated at 100 K with 200 keV Ar 2+ . Rutherford backscattering spectroscopy and ion channeling with 2 MeV He + ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 x 10 15 Ar 2+ cm -2 , considerable near-surface He + ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 mm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO 3 ) and spinel (MgAl 2 O 4 ) to explore factors that may influence radiation damage response in oxides

  16. Development of cryogenic permanent magnet undulator

    International Nuclear Information System (INIS)

    Hara, Toru; Tanaka, Takashi; Shirasawa, Katsutoshi; Kitamura, Hideo; Bizen, Teruhiko; Seike, Takamitsu; Marechal, Xavier; Tsuru, Rieko; Iwaki, Daisuke

    2005-01-01

    A short period undulator increases not only the photon energy of undulator radiation, but also the brilliance due to its increased number of undulator periods. As a result, brilliant undulator radiation becomes available in the photon energy range, which is currently covered by wigglers. In order to develop a short period undulator, high performance magnets are indispensable and superconductive undulators have been actively investigated in recent years. In this paper, however, we propose a new approach, so called a cryogenic permanent magnet undulator using NdFeB magnets at the temperatures around 150 K. The current status of this cryogenic permanent magnet undulator development at SPring-8 is presented including the results of the magnetic field measurements on a prototype undulator. (author)

  17. Cryogenic in situ microcompression testing of Sn

    International Nuclear Information System (INIS)

    Lupinacci, A.; Kacher, J.; Eilenberg, A.; Shapiro, A.A.; Hosemann, P.; Minor, A.M.

    2014-01-01

    Characterizing plasticity mechanisms below the ductile-to-brittle transition temperature is traditionally difficult to accomplish in a systematic fashion. Here, we use a new experimental setup to perform in situ cryogenic mechanical testing of pure Sn micropillars at room temperature and at −142 °C. Subsequent electron microscopy characterization of the micropillars shows a clear difference in the deformation mechanisms at room temperature and at cryogenic temperatures. At room temperature, the Sn micropillars deformed through dislocation plasticity, while at −142 °C they exhibited both higher strength and deformation twinning. Two different orientations were tested, a symmetric (1 0 0) orientation and a non-symmetric (4 5 ¯ 1) orientation. The deformation mechanisms were found to be the same for both orientations

  18. Characterization of titanium alloys for cryogenic applications

    International Nuclear Information System (INIS)

    Reytier, M.; Kircher, F.; Levesy, B.

    2002-01-01

    Titanium alloys are employed in the design of superconducting magnet support systems for their high mechanical strength associated with their low thermal conductivity. But their use requires a careful attention to their crack tolerance at cryogenic temperature. Measurements have been performed on two extra low interstitial materials (Ti-5Al-2.5Sn ELI and Ti-6Al-4V ELI) with different thickness and manufacturing process. The investigation includes the tensile properties at room and liquid helium temperatures using smooth and notched samples. Moreover, the fracture toughness has been determined at 4.2 K using Compact Tension specimens. The microstructure of the different alloys and the various fracture surfaces have also been studied. After a detailed description of the experimental procedures, practical engineering characteristics are given and a comparison of the different titanium alloys is proposed for cryogenic applications

  19. Cryogenic cooling for high power laser amplifiers

    Directory of Open Access Journals (Sweden)

    Perin J.P.

    2013-11-01

    Full Text Available Using DPSSL (Diode Pumped Solid State Lasers as pumping technology, PW-class lasers with enhanced repetition rates are developed. Each of the Yb YAG amplifiers will be diode-pumped at a wavelength of 940 nm. This is a prerequisite for achieving high repetition rates (light amplification duration 1 millisecond and repetition rate 10 Hz. The efficiency of DPSSL is inversely proportional to the temperature, for this reason the slab amplifier have to be cooled at a temperature in the range of 100 K–170 K with a heat flux of 1 MW*m−2. This paper describes the thermo-mechanical analysis for the design of the amplification laser head, presents a preliminary proposal for the required cryogenic cooling system and finally outlines the gain of cryogenic operation for the efficiency of high pulsed laser.

  20. Test of a cryogenic helium pump

    International Nuclear Information System (INIS)

    Lue, J.W.; Miller, J.R.; Walstrom, P.L.; Herz, W.

    1981-01-01

    The design of a cryogenic helium pump for circulating liquid helium in a magnet and the design of a test loop for measuring the pump performance in terms of mass flow vs pump head at various pump speeds are described. A commercial cryogenic helium pump was tested successfully. Despite flaws in the demountable connections, the piston pump itself has performed satisfactorily. A helium pump of this type is suitable for the use of flowing supercritical helium through Internally Cooled Superconductor (ICS) magnets. It has pumped supercritical helium up to 7.5 atm with a pump head up to 2.8 atm. The maximum mass flow rate obtained was about 16 g/s. Performance of the pump was degraded at lower pumping speeds

  1. Producing and Recognizing Analogical Relations

    Science.gov (United States)

    Lipkens, Regina; Hayes, Steven C

    2009-01-01

    Analogical reasoning is an important component of intelligent behavior, and a key test of any approach to human language and cognition. Only a limited amount of empirical work has been conducted from a behavior analytic point of view, most of that within Relational Frame Theory (RFT), which views analogy as a matter of deriving relations among relations. The present series of four studies expands previous work by exploring the applicability of this model of analogy to topography-based rather than merely selection-based responses and by extending the work into additional relations, including nonsymmetrical ones. In each of the four studies participants pretrained in contextual control over nonarbitrary stimulus relations of sameness and opposition, or of sameness, smaller than, and larger than, learned arbitrary stimulus relations in the presence of these relational cues and derived analogies involving directly trained relations and derived relations of mutual and combinatorial entailment, measured using a variety of productive and selection-based measures. In Experiment 1 participants successfully recognized analogies among stimulus networks containing same and opposite relations; in Experiment 2 analogy was successfully used to extend derived relations to pairs of novel stimuli; in Experiment 3 the procedure used in Experiment 1 was extended to nonsymmetrical comparative relations; in Experiment 4 the procedure used in Experiment 2 was extended to nonsymmetrical comparative relations. Although not every participant showed the effects predicted, overall the procedures occasioned relational responses consistent with an RFT account that have not yet been demonstrated in a behavior-analytic laboratory setting, including productive responding on the basis of analogies. PMID:19230515

  2. Thermodynamic Vent System for an On-Orbit Cryogenic Reaction Control Engine

    Science.gov (United States)

    Hurlbert, Eric A.; Romig, Kris A.; Jimenez, Rafael; Flores, Sam

    2012-01-01

    A report discusses a cryogenic reaction control system (RCS) that integrates a Joule-Thompson (JT) device (expansion valve) and thermodynamic vent system (TVS) with a cryogenic distribution system to allow fine control of the propellant quality (subcooled liquid) during operation of the device. It enables zero-venting when coupled with an RCS engine. The proper attachment locations and sizing of the orifice are required with the propellant distribution line to facilitate line conditioning. During operations, system instrumentation was strategically installed along the distribution/TVS line assembly, and temperature control bands were identified. A sub-scale run tank, full-scale distribution line, open-loop TVS, and a combination of procured and custom-fabricated cryogenic components were used in the cryogenic RCS build-up. Simulated on-orbit activation and thruster firing profiles were performed to quantify system heat gain and evaluate the TVS s capability to maintain the required propellant conditions at the inlet to the engine valves. Test data determined that a small control valve, such as a piezoelectric, is optimal to provide continuously the required thermal control. The data obtained from testing has also assisted with the development of fluid and thermal models of an RCS to refine integrated cryogenic propulsion system designs. This system allows a liquid oxygenbased main propulsion and reaction control system for a spacecraft, which improves performance, safety, and cost over conventional hypergolic systems due to higher performance, use of nontoxic propellants, potential for integration with life support and power subsystems, and compatibility with in-situ produced propellants.

  3. Cryogenic freezing of fresh date fruits for quality preservation during frozen storage

    Directory of Open Access Journals (Sweden)

    Abdullah Alhamdan

    2018-01-01

    Full Text Available Fresh date fruits, especially Barhi cultivar, are favored and widely consumed at the Khalal maturity stage (first color edible stage. These fruits are seasonal and perishable and there is a need for extending their shelf life. This study evaluates two different freezing methods, namely cryogenic freezing using liquid nitrogen and conventional deep freezing on preserving the quality and stability of date fruits (cv. Barhi at Khalal maturity stage. Fresh date fruits (cv. Barhi at Khalal stage were frozen utilizing the two methods. The produced frozen dates were stored under frozen storage conditions for nine months (at −20 °C and −40 °C for the conventional and cryogenic freezing, respectively. Color values, textural properties (hardness, elasticity, chewiness and resilience, and nutrition attributes (enzymes and sugars for fresh dates before freezing and for the frozen dates were measured every three months during the frozen storage. Color values of the frozen dates were affected by the freezing method and the frozen storage period. There are substantial differences in the quality of the frozen fruits in favor of cryogenic freezing compared to the conventional slow freezing. The results revealed a large disparity between the times of freezing of the two methods. The freezing time accounted to 10 min in the cryogenic freezing method, whereas it was 1800 min for the conventional slow freezing system.

  4. Results of KEPCO HTS cable system tests and design of hybrid cryogenic system

    International Nuclear Information System (INIS)

    Lim, J.H.; Sohn, S.H.; Yang, H.S.; Hwang, S.D.; Kim, D.L.; Ryoo, H.S.; Choi, H.O.

    2010-01-01

    In order to investigate the compatibility as a power utility facility, Korea Electric Power Corporation (KEPCO) had installed a 22.9 kV, 1250 A, 100 m long high temperature superconducting (HTS) power cable system. Using the HTS cable, various tests have been performed to investigate electrical and thermo-mechanical properties. Since 2005, a series of thermal cycle tests between liquid nitrogen (LN 2 ) and ambient temperatures have been conducted using a vacuum-pump driven open-loop cryogenic system with a capacity of 3 kW. In the tests, although the open-loop cryogenic system was reliable to operate the HTS cable system, it was not effective in economic view point because LN 2 consumption was larger than expected. In order to secure against unexpected emergencies and solve the problem of LN 2 consumption, a hybrid cryogenic system was designed and installed. A stirling cryocooler was employed and combined with the open-loop cryogenic system. Considering the average heat load at rated condition, the cooling capacity of the cryocooler was determined to 4 kW at 77 K. In this paper, results of performance tests and the design of the hybrid cooling system are presented.

  5. Conceptual design of the cryogenic system and estimation of the recirculated power for CFETR

    Science.gov (United States)

    Liu, Xiaogang; Qiu, Lilong; Li, Junjun; Wang, Zhaoliang; Ren, Yong; Wang, Xianwei; Li, Guoqiang; Gao, Xiang; Bi, Yanfang

    2017-01-01

    The China Fusion Engineering Test Reactor (CFETR) is the next tokamak in China’s roadmap for realizing commercial fusion energy. The CFETR cryogenic system is crucial to creating and maintaining operational conditions for its superconducting magnet system and thermal shields. The preliminary conceptual design of the CFETR cryogenic system has been carried out with reference to that of ITER. It will provide an average capacity of 75 to 80 kW at 4.5 K and a peak capacity of 1300 kW at 80 K. The electric power consumption of the cryogenic system is estimated to be 24 MW, and the gross building area is about 7000 m2. The relationships among the auxiliary power consumed by the cryogenic system, the fusion power gain and the recirculated power of CFETR are discussed, with the suggestion that about 52% of the electric power produced by CFETR in phase II must be recirculated to run the fusion test reactor.

  6. Experimental investigation on hydrogen cryogenic distillation equipped with package made by ICIT

    International Nuclear Information System (INIS)

    Bornea, A.; Zamfirache, M.; Stefan, L.; Stefanescu, I.; Preda, A.

    2015-01-01

    ICIT (Institute for Cryogenics and Isotopic Technologies) has used its experience in cryogenic water distillation process to propose a similar process for hydrogen distillation that can be used in detritiation technologies. This process relies on the same packages but a stainless filling is tested instead of the phosphorous bronze filling used for water distillation. This paper presents two types of packages developed for hydrogen distillation, both have a stainless filling but it differs in terms of density, exchange surface and specific volume. Performance data have been obtained on laboratory scale. In order to determine the characteristics of the package, the installation was operated in the total reflux mode, for different flow rate for the liquid. There were made several experiments considering different operating conditions. Samples extracted at the top and bottom of cryogenic distillation column allowed mathematical processing to determine the separation performance. The experiments show a better efficiency for the package whose exchange surface was higher and there were no relevant differences between both packages as the operating pressure of the cryogenic column was increasing. For a complete characterization of the packages, future experiments will be considered to determine performance at various velocities in the column and their correlation with the pressure in the column. We plan further experiments to separate tritium from the mixture of isotopes DT, having in view that our goal is to apply this results to a detritiation plant

  7. Automatic Management Systems for the Operation of the Cryogenic Test Facilities for LHC Series Superconducting Magnets

    CERN Document Server

    Tovar-Gonzalez, A; Herblin, L; Lamboy, J P; Vullierme, B

    2006-01-01

    Prior to their final preparation before installation in the tunnel, the ~1800 series superconducting magnets of the LHC machine shall be entirely tested at reception on modular test facilities. The operation 24 hours per day of the cryogenic test facilities is conducted in turn by 3-operator teams, assisted in real time by the use of the Test Bench Priorities Handling System, a process control application enforcing the optimum use of cryogenic utilities and of the "Tasks Tracking System", a web-based e-traveller application handling 12 parallel 38-task test sequences. This paper describes how such computer-based management systems can be used to optimize operation of concurrent test benches within technical boundary conditions given by the cryogenic capacity, and how they can be used to study the efficiency of the automatic steering of all individual cryogenic sub-systems. Finally, this paper presents the overall performance of the cryomagnet test station for the first complete year of operation at high produ...

  8. Uses of cryogenics in power industry

    Energy Technology Data Exchange (ETDEWEB)

    Jungnickel, H

    1975-05-01

    A review of the present and possible future uses of cryogenic engineering and applied superconductivity. The applications discussed cover: transport of natural gas, superconducting N/sub 2/-filled cable for 275 kV. Cable with Ni/Ti conductor, homopolar machines with dix-type superconducting field coils, and superconducting magnetic propulsion. Important references to original works from different countries describing the latest developments are given.

  9. Experiments with a cryogenic torsion balance

    International Nuclear Information System (INIS)

    Newman, R.D.

    1983-01-01

    The torsion balance is a remarkably capable instrument for the measurement of slowly varying exceedingly small forces; indeed its potential abilities are still largely untapped. The author outlines some of the virtues (and limitations) of the torsion balance, and presents a menu of gravitation-related experiments to which it may be applied. He discusses plans for developing torsion balances operating at cryogenic temperatures, and describes an experiment to search for anomalous long-range interactions associated with intrinsic spin. (Auth.)

  10. Strong, Ductile Rotor For Cryogenic Flowmeters

    Science.gov (United States)

    Royals, W. T.

    1993-01-01

    Improved magnetic flowmeter rotor resists cracking at cryogenic temperatures, yet provides adequate signal to magnetic pickup outside flowmeter housing. Consists mostly of stainless-steel alloy 347, which is ductile and strong at low temperatures. Small bead of stainless-steel alloy 410 welded in groove around circumference of round bar of stainless-steel alloy 347; then rotor machined from bar. Tips of rotor blades contain small amounts of magnetic alloy, and passage of tips detected.

  11. A breath of fresh air for cryogenics training

    CERN Multimedia

    HSE Unit

    2014-01-01

    Whether you work full-time in a cryogenic installation or are required to handle cryogenic substances temporarily, you need to have followed the appropriate safety training.   Photo: Christoph Balle. Two new training courses are now available in English and French at CERN: “Cryogenic Safety – Fundamentals” (at the Prévessin Training Centre) and “Cryogenic Safety – Helium Transfer” (at the Cryolab). The first covers the content of levels 1 and 2 of the old “Cryogenic Safety” course. The second is a completely new course for CERN: it covers specific aspects of the transfer of liquid helium, such as the evaporation process of helium and the associated risks to human health (asphyxia due to displacement of oxygen), the colour code for gas bottles, etc. These training modules have been rewritten in response to the increase in the number of projects involving cryogenics and following various related incident...

  12. Cryogenic system for TRISTAN superconducting RF cavities

    International Nuclear Information System (INIS)

    Hosoyama, K.; Hara, K.; Kabe, A.; Kojima, Y.; Ogitsu, T.; Sakamoto, Y.; Kawamura, S.; Matsumoto, K.

    1993-01-01

    A large cryogenic system has been designed, constructed and operated in the TRISTAN electron-positron collider at KEK for 508 MHz, 32x5-cell superconducting RF cavities. A 6.5 kW, 4.4 K helium refrigerator with 5 turbo-expanders on the ground level supplies liquid helium in parallel to the 16 cryostats in the TRISTAN tunnel through about 250 m long multichannel transfer line. Two 5-cell cavities are coupled together, enclosed in a cryostat and cooled by about 830 L pool boiling liquid helium. A liquid nitrogen circulation system with a turbo-expander has been adopted for 80 K radiation shields in the multichannel transfer line and the cryostats to reduce liquid nitrogen consumption and to increase the operation stability of the system. The cryogenic system has a total of about 18 000 hours of operating time from the first cool down test in August 1988 to November 1991. The design principle and outline of the cryogenic system and the operational experience are presented. (orig.)

  13. Fast multichannel analog storage system

    International Nuclear Information System (INIS)

    Freytag, D.R.

    1982-11-01

    A Multichannel Analog Storage System based on a commercial 32-channel parallel in/serial out (PISO) analog shift register is described. The basic unit is a single width CAMAC module containing 512 analog cells and the associated logic for data storage and subsequent readout. At sampling rates of up to 30 MHz the signals are strobed directly into the PISO. At higher rates signals are strobed into a fast presampling stage and subsequently transferred in block form into an array of PISO's. Sampling rates of 300 MHz have been achieved with the present device and 1000 MHz are possible with improved signal drivers. The system is well suited for simultaneous handling of many signal channels with moderate numbers of samples in each channel. RMS noise over full scale signal has been measured as 1:3000 (approx. = 11 bit). However, nonlinearities in the response and differences in sensitivity of the analog cells require an elaborate calibration system in order to realize 11 bit accuracy for the analog information

  14. PIP-II Cryogenic System and the evolution of Superfluid Helium Cryogenic Plant Specifications

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarty, Anindya [Fermilab; Rane, Tejas [Fermilab; Klebaner, Arkadiy [Fermilab

    2017-07-06

    The PIP-II cryogenic system consists of a Superfluid Helium Cryogenic Plant (SHCP) and a Cryogenic Distribution System (CDS) connecting the SHCP to the Superconducting (SC) Linac consisting of 25 cryomodules. The dynamic heat load of the SC cavities for continuous wave (CW) as well as pulsed mode of operation has been listed out. The static heat loads of the cavities along with the CDS have also been discussed. Simulation study has been carried out to compute the supercritical helium (SHe) flow requirements for each cryomodule. Comparison between the flow requirements of the cryomodules for the CW and pulsed modes of operation have also been made. From the total computed heat load and pressure drop values in the CDS, the basic specifications for the SHCP, required for cooling the SC Linac, have evolved.

  15. Cryogenic Safety HSE Seminar | 21 - 23 September 2016

    CERN Multimedia

    2016-01-01

    With the LHC being the world’s largest superconducting installation, it’s not surprising that CERN is a world leader in cryogenic safety. On 21 and 22 September, over 100 experts in cryogenic safety will be coming to CERN to take part in CERN’s first Cryogenic Safety Seminar, which aims to stimulate collaboration and further the state of the art in this increasingly important field.  

  16. Some General Principles in Cryogenic Design, Implementation, and Testing

    Science.gov (United States)

    Dipirro, Michael James

    2015-01-01

    Brief Course Description: In 2 hours only the most basic principles of cryogenics can be presented. I will concentrate on the differences between a room temperature thermal analysis and cryogenic thermal analysis, namely temperature dependent properties. I will talk about practical materials for thermal contact and isolation. I will finish by describing the verification process and instrumentation used that is unique to cryogenic (in general less than 100K) systems.

  17. Synthesis of pure ozone by nanosecond discharge at cryogenic temperatures

    International Nuclear Information System (INIS)

    Amirov, R.H.; Asinovsky, E.I.; Samoilov, I.S.

    1996-01-01

    Synthesis of pure ozone by nanosecond discharge at cryogenic temperatures was experimentally examined. The average ozone concentration in the volume of the discharge tube was less at cryogenic temperatures than at room temperatures. The production of condensed ozone have been determined by measuring the ozone concentration when the walls was heated and ozone evaporated. The energy yield of ozone generation at cryogenic temperatures has been calculated. The maximum value was 200 g/kWh

  18. Biomedical sensor design using analog compressed sensing

    Science.gov (United States)

    Balouchestani, Mohammadreza; Krishnan, Sridhar

    2015-05-01

    The main drawback of current healthcare systems is the location-specific nature of the system due to the use of fixed/wired biomedical sensors. Since biomedical sensors are usually driven by a battery, power consumption is the most important factor determining the life of a biomedical sensor. They are also restricted by size, cost, and transmission capacity. Therefore, it is important to reduce the load of sampling by merging the sampling and compression steps to reduce the storage usage, transmission times, and power consumption in order to expand the current healthcare systems to Wireless Healthcare Systems (WHSs). In this work, we present an implementation of a low-power biomedical sensor using analog Compressed Sensing (CS) framework for sparse biomedical signals that addresses both the energy and telemetry bandwidth constraints of wearable and wireless Body-Area Networks (BANs). This architecture enables continuous data acquisition and compression of biomedical signals that are suitable for a variety of diagnostic and treatment purposes. At the transmitter side, an analog-CS framework is applied at the sensing step before Analog to Digital Converter (ADC) in order to generate the compressed version of the input analog bio-signal. At the receiver side, a reconstruction algorithm based on Restricted Isometry Property (RIP) condition is applied in order to reconstruct the original bio-signals form the compressed bio-signals with high probability and enough accuracy. We examine the proposed algorithm with healthy and neuropathy surface Electromyography (sEMG) signals. The proposed algorithm achieves a good level for Average Recognition Rate (ARR) at 93% and reconstruction accuracy at 98.9%. In addition, The proposed architecture reduces total computation time from 32 to 11.5 seconds at sampling-rate=29 % of Nyquist rate, Percentage Residual Difference (PRD)=26 %, Root Mean Squared Error (RMSE)=3 %.

  19. Design, production, and testing of field effect transistors. [cryogenic MOSFETS

    Science.gov (United States)

    Sclar, N.

    1982-01-01

    Cryogenic MOSFETS (CRYOFETS), specifically designed for low temperature preamplifier application with infrared extrinsic detectors were produced and comparatively tested with p-channel MOSFETs under matched conditions. The CRYOFETs exhibit lower voltage thresholds, high source-follower gains at lower bias voltage, and lower dc offset source voltage. The noise of the CRYOFET is found to be 2 to 4 times greater than the MOSFET with a correspondingly lower figure of merit (which is established for source-follower amplifiers). The device power dissipation at a gain of 0.98 is some two orders of magnitude lower than for the MOSFET. Further, CRYOFETs are free of low temperature I vs V character hysteresis and balky conduction turn-on effects and operate effectively in the 2.4 to 20 K range. These devices have promise for use on long term duration sensor missions and for on-focal-plane signal processing at low temperatures.

  20. Environmental compatibility of CRYOPLANE the cryogenic-fuel aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Klug, H G [Daimler Benz Aerospace Airbus, Hamburg (Germany)

    1998-12-31

    `CRYOPLANE` is the project name for an aircraft powered by cryogenic fuel, either liquid natural gas (LNG, mainly consisting of methane) or liquid hydrogen (LH{sub 2}). Emission of CO{sub 2}, unburnt hydrocarbons, soot and sulfur will be completely avoided by hydrogen combustion: LH{sub 2} is an extremely pure liquid. Emission of water as a primary combustion product is increased by a factor of 2.6. Exhaust gases behind hydrogen engines contain more water than behind kerosene engines, and hence can form contrails under a wider range of atmospheric conditions. Liquid hydrogen fueled aircraft promise big advantages relative to kerosene aircraft in terms of environmental compatibility. (R.P.)

  1. Environmental compatibility of CRYOPLANE the cryogenic-fuel aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Klug, H.G. [Daimler Benz Aerospace Airbus, Hamburg (Germany)

    1997-12-31

    `CRYOPLANE` is the project name for an aircraft powered by cryogenic fuel, either liquid natural gas (LNG, mainly consisting of methane) or liquid hydrogen (LH{sub 2}). Emission of CO{sub 2}, unburnt hydrocarbons, soot and sulfur will be completely avoided by hydrogen combustion: LH{sub 2} is an extremely pure liquid. Emission of water as a primary combustion product is increased by a factor of 2.6. Exhaust gases behind hydrogen engines contain more water than behind kerosene engines, and hence can form contrails under a wider range of atmospheric conditions. Liquid hydrogen fueled aircraft promise big advantages relative to kerosene aircraft in terms of environmental compatibility. (R.P.)

  2. Optimal design of gas adsorption refrigerators for cryogenic cooling

    Science.gov (United States)

    Chan, C. K.

    1983-01-01

    The design of gas adsorption refrigerators used for cryogenic cooling in the temperature range of 4K to 120K was examined. The functional relationships among the power requirement for the refrigerator, the system mass, the cycle time and the operating conditions were derived. It was found that the precool temperature, the temperature dependent heat capacities and thermal conductivities, and pressure and temperature variations in the compressors have important impacts on the cooling performance. Optimal designs based on a minimum power criterion were performed for four different gas adsorption refrigerators and a multistage system. It is concluded that the estimates of the power required and the system mass are within manageable limits in various spacecraft environments.

  3. Large Eddy Simulation of Cryogenic Injection Processes at Supercritical Pressure

    Science.gov (United States)

    Oefelein, Joseph C.

    2002-01-01

    This paper highlights results from the first of a series of hierarchical simulations aimed at assessing the modeling requirements for application of the large eddy simulation technique to cryogenic injection and combustion processes in liquid rocket engines. The focus is on liquid-oxygen-hydrogen coaxial injectors at a condition where the liquid-oxygen is injected at a subcritical temperature into a supercritical environment. For this situation a diffusion dominated mode of combustion occurs in the presence of exceedingly large thermophysical property gradients. Though continuous, these gradients approach the behavior of a contact discontinuity. Significant real gas effects and transport anomalies coexist locally in colder regions of the flow, with ideal gas and transport characteristics occurring within the flame zone. The current focal point is on the interfacial region between the liquid-oxygen core and the coaxial hydrogen jet where the flame anchors itself.

  4. A High Reliability Gas-driven Helium Cryogenic Centrifugal Compressor

    CERN Document Server

    Bonneton, M; Gistau-Baguer, Guy M; Turcat, F; Viennot, P

    1998-01-01

    A helium cryogenic compressor was developed and tested in real conditions in 1996. The achieved objective was to compress 0.018 kg/s Helium at 4 K @ 1000 Pa (10 mbar) up to 3000 Pa (30 mbar). This project was an opportunity to develop and test an interesting new concept in view of future needs. The main features of this new specific technology are described. Particular attention is paid to the gas bearing supported rotor and to the pneumatic driver. Trade off between existing technologies and the present work are presented with special stress on the bearing system and the driver. The advantages are discussed, essentially focused on life time and high reliability without maintenance as well as non pollution characteristic. Practical operational modes are also described together with the experimental performances of the compressor. The article concludes with a brief outlook of future work.

  5. The DFBX cryogenic distribution boxes for the LHC straight sections

    International Nuclear Information System (INIS)

    Zbasnik, Jon P.; Corradi, Carol A.; Green, Michael A.; Kajiyama, Y.; Knolls, Michael J.; LaMantia, Roberto F.; Rasson, Joseph E.; Reavill, Dulie; Turner, William C.

    2002-01-01

    The DFBX distribution boxes are designed to connect the LHC cryogenic distribution system to the interaction region quadrupoles [1] and dipoles for the Large Hadron Collider (LHC). The DFBX distribution boxes also have the current leads for the superconducting interaction region magnets and the LHC interaction region correction coils. The DFBX boxes also connect the magnet and cryogenic instrumentation to the CERN data collection system. The DFBX boxes serve as the cryogenic circulation center and the nerve center for four of the LHC straight sections. This report describes primarily the cryogenic function of the DFBXs

  6. Thermal Stabilization of Cryogenic System in Superconducting Cyclotron

    International Nuclear Information System (INIS)

    Shin, Seung Jae; Kim, Kyung Min; Cho, Hyung Hee; Hong, Bong Hwan; Kang, Joon Sun; Ahn, Dong Hyun

    2011-01-01

    Radiology has some useful applications for medical purpose. For cancer therapy, the superconducting cyclotron should generate heavy ion beams. It radiates heavy ion beams to cancer patients. In order to make cyclotron system stable, the cryogenic system which makes superconducting state should work constantly. However, radiation heat transfer of cryogenic system should be considered because liquid helium's boiling point is extremely low and there is huge temperature difference between the cryogenic system and ambient temperature. Accordingly, thermal analysis should be carried out. In this paper, the numerical analysis of the cryogenic system in practical superconducting cyclotron show temperature distribution and suggest the number of coolers using ANSYS Workbench program

  7. High Reliability Cryogenic Piezoelectric Valve Actuator, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic fluid valves are subject to harsh exposure and actuators to drive these valves require robust performance and high reliability. DSM's piezoelectric...

  8. Analog electronics for radiation detection

    CERN Document Server

    2016-01-01

    Analog Electronics for Radiation Detection showcases the latest advances in readout electronics for particle, or radiation, detectors. Featuring chapters written by international experts in their respective fields, this authoritative text: Defines the main design parameters of front-end circuitry developed in microelectronics technologies Explains the basis for the use of complementary metal oxide semiconductor (CMOS) image sensors for the detection of charged particles and other non-consumer applications Delivers an in-depth review of analog-to-digital converters (ADCs), evaluating the pros and cons of ADCs integrated at the pixel, column, and per-chip levels Describes incremental sigma delta ADCs, time-to-digital converter (TDC) architectures, and digital pulse-processing techniques complementary to analog processing Examines the fundamental parameters and front-end types associated with silicon photomultipliers used for single visible-light photon detection Discusses pixel sensors ...

  9. Natural analogs for Yucca Mountain

    International Nuclear Information System (INIS)

    Murphy, W.M.

    1995-01-01

    High-level radioactive waste in the US, spent fuels from commercial reactors and nuclear materials generated by defense activities, will remain potentially hazardous for thousands of years. Demonstrable long-term stability of certain geologic and geochemical systems motivates and sustains the concept that high-level waste can be safely isolated in geologic repositories for requisite periods of time. Each geologic repository is unique in its properties and performance with reguard to isolation of nuclear wastes. Studies of processes analogous to waste-form alteration and radioelement transport in environments analogous to Yucca Mountain are being conducted at two sites, described in this article to illustrate uses of natural analog data: the Nopal I uranium deposit in the Sierra Pena Blanca, Mexico, and the Akrotiri archaeological site on the island of Santorini, Greece

  10. Synthetic Analogs of Phospholipid Metabolites as Antimalarials.

    Science.gov (United States)

    1979-07-01

    phosphatidic acid analogs containing ether and phosphonate groups; completely non- hydrolyzable lecithin analogs containing phosphinate and ether groups...substance is a completely non- hydrolyzable analog of lecithin containing ether and phosphonate moieties instead of the normally labile carboxylic and...and also ant-i-phospholipase C (clostridial enzyme) activity. This substance Is a completely non- hydrolyzable analog of lecithin containing ether

  11. Series Supply of Cryogenic Venturi Flowmeters for the ITER Project

    International Nuclear Information System (INIS)

    André, J; Poncet, J M; Ercolani, E; Clayton, N; Journeaux, J Y

    2015-01-01

    In the framework of the ITER project, the CEA-SBT has been contracted to supply 277 venturi tube flowmeters to measure the distribution of helium in the superconducting magnets of the ITER tokamak. Six sizes of venturi tube have been designed so as to span a measurable helium flowrate range from 0.1 g/s to 400g/s. They operate, in nominal conditions, either at 4K or at 300K, and in a nuclear and magnetic environment. Due to the cryogenic conditions and the large number of venturi tubes to be supplied, an individual calibration of each venturi tube would be too expensive and time consuming. Studies have been performed to produce a design which will offer high repeatability in manufacture, reduce the geometrical uncertainties and improve the final helium flowrate measurement accuracy. On the instrumentation side, technologies for differential and absolute pressure transducers able to operate in applied magnetic fields need to be identified and validated. The complete helium mass flow measurement chain will be qualified in four test benches: - A helium loop at room temperature to insure the qualification of a statistically relevant number of venturi tubes operating at 300K.- A supercritical helium loop for the qualification of venturi tubes operating at cryogenic temperature (a modification to the HELIOS test bench). - A dedicated vacuum vessel to check the helium leak tightness of all the venturi tubes. - A magnetic test bench to qualify different technologies of pressure transducer in applied magnetic fields up to 100mT. (paper)

  12. Fiber-Optic Continuous Liquid Sensor for Cryogenic Propellant Gauging

    Science.gov (United States)

    Xu. Wei

    2010-01-01

    An innovative fiber-optic sensor has been developed for low-thrust-level settled mass gauging with measurement uncertainty optical fiber to measure liquid level and liquid distribution of cryogenic propellants. Every point of the sensing fiber is a point sensor that not only distinguishes liquid and vapor, but also measures temperature. This sensor is able to determine the physical location of each point sensor with 1-mm spatial resolution. Acting as a continuous array of numerous liquid/vapor point sensors, the truly distributed optical sensing fiber can be installed in a propellant tank in the same manner as silicon diode point sensor stripes using only a single feedthrough to connect to an optical signal interrogation unit outside the tank. Either water or liquid nitrogen levels can be measured within 1-mm spatial resolution up to a distance of 70 meters from the optical interrogation unit. This liquid-level sensing technique was also compared to the pressure gauge measurement technique in water and liquid nitrogen contained in a vertical copper pipe with a reasonable degree of accuracy. It has been demonstrated that the sensor can measure liquid levels in multiple containers containing water or liquid nitrogen with one signal interrogation unit. The liquid levels measured by the multiple fiber sensors were consistent with those virtually measured by a ruler. The sensing performance of various optical fibers has been measured, and has demonstrated that they can survive after immersion at cryogenic temperatures. The fiber strength in liquid nitrogen has also been measured. Multiple water level tests were also conducted under various actual and theoretical vibration conditions, and demonstrated that the signal-to-noise ratio under these vibration conditions, insofar as it affects measurement accuracy, is manageable and robust enough for a wide variety of spacecraft applications. A simple solution has been developed to absorb optical energy at the termination of

  13. Analog to digital conversion for nuclear spectrometry

    International Nuclear Information System (INIS)

    Carvalho, P.V.R. de.

    1982-04-01

    A study of the analog to digital conversion techniques for nuclear spectrometry is presented and the main design philosophies of nuclear ADC's are compared. Among them, the most suitable for the current Brazilian conditions, concerning the specifications and components avaiability is the one that employs a statistical correction of successive approximation converters. This technique is described in full detail. A prototype has been developed an tested for the practical demonstration of the theoretical conclusions. These tests was carried on nuclear spectrometry data aquisition system whose implementation is also described. (Author) [pt

  14. Cryogenic beam loss monitoring for the LHC

    International Nuclear Information System (INIS)

    Kurfürst, C.

    2013-01-01

    A Beam Loss Monitoring (BLM) system was installed on the outside surface of the LHC magnet cryostats to protect the accelerator equipment from beam losses. The protection is achieved by extracting the beam from the ring in case thresholds imposed on measured radiation levels are exceeded. Close to the interaction regions of the LHC, the present BLM system is sensitive to particle showers generated in the interaction region of the two beams. In the future, with beams of higher energy and brightness resulting in higher luminosity, distinguishing between these interaction products and possible quench-provoking beam losses from the primary proton beams will be challenging. The particle showers measured by the present BLM configuration are partly shielded by the cryostat and the iron yoke of the magnets. The system can hence be optimised by locating beam loss monitors as close as possible to the protected element, i. e. the superconducting coils, inside the cold mass of the magnets in superfluid helium at 1.9 K. The advantage is that the dose measured by the Cryogenic Beam Loss Monitor (CryoBLM) would more precisely correspond to the dose deposited in the superconducting coil. The main challenges of this placement are the low temperature of 1.9 K and the integrated dose of 2 MGy in 20 years. Furthermore the CryoBLM should work in a magnetic field of 2 T and at a pressure of 1.1 bar, withstanding a fast pressure rise up to 20 bar in case of a magnet quench. The detector response should be linear between 0.1 and 10 mGy/s and faster than 1 ms. Once the detectors are installed in the LHC magnets, no access will be possible. Hence the detectors need to be available, reliable and stable for 20 years. Following intense research it became clear that no existing technology was proven to work in such conditions. The candidates under investigation in this work are diamond and silicon detectors and an ionisation chamber, using the liquid helium itself as particle detection medium

  15. Development of bonding techniques for cryogenic components. 1. HIP bonding tests between Ti and cryogenic stainless steels

    International Nuclear Information System (INIS)

    Saito, Shigeru; Ouchi, Nobuo; Ishiyama, Shintaro; Tsuchiya, Yoshinori; Nakajima, Hideo

    2002-05-01

    Around the super conducting (SC) coils of SC linear accelerator or fusion reactor, several kinds of dissimilar material joints will be needed. In case of fusion reactor, pure titanium has been proposed as jacket material of SC coil. Pure titanium has many advantages, for instance, almost same thermal expansion with Nb 3 Sn SC coil, non-magnetivity and good workability. However, it is difficult to bond Ti and cryogenic stainless steels by welding. Therefore, it is necessary to develop new bonding techniques and we started the development of the bonding technology by hot isostatic press (HIP) method to bond titanium with stainless steels. In this experiments, optimization of HIP bonding condition and evaluation of bonding strength were performed by metallurgical observation, mechanical property tests and heat cycle test. (author)

  16. Multichannel analog temperature sensing system

    International Nuclear Information System (INIS)

    Gribble, R.

    1985-08-01

    A multichannel system that protects the numerous and costly water-cooled magnet coils on the translation section of the FRX-C/T magnetic fusion experiment is described. The system comprises a thermistor for each coil, a constant current circuit for each thermistor, and a multichannel analog-to-digital converter interfaced to the computer

  17. 49205 ANALOGE OG DIGITALE FILTRE

    DEFF Research Database (Denmark)

    Gaunholt, Hans

    1997-01-01

    Theese lecture notes treats the fundamental theory and the most commonly used design methods for passive- active and digital filters with special emphasis on microelectronic realizations. The lecture notes covers 75% of the material taught in the course 49205 Analog and Digital Filters...

  18. Drawing Analogies to Deepen Learning

    Science.gov (United States)

    Fava, Michelle

    2017-01-01

    This article offers examples of how drawing can facilitate thinking skills that promote analogical reasoning to enable deeper learning. The instructional design applies cognitive principles, briefly described here. The workshops were developed iteratively, through feedback from student and teacher participants. Elements of the UK National…

  19. THERMAL AND THERMO-MECHANICAL CHARACTERISTICS OF CRYOGENIC MICROCOOLER FOR OPTIMUM PERFORMANCE AND RELIABILITY

    Science.gov (United States)

    2017-10-19

    reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of...contracted fundamental research deemed exempt from public affairs security and policy review in accordance with SAF/AQR memorandum dated 10 Dec 08 and AFRL...subjected to cryogenic operating conditions was assessed by proposing a hierarchical physics -of-failure-based reliability assessment model. 15. SUBJECT

  20. Modeling of cryogenic frictional behaviour of titanium alloys using Response Surface Methodology approach

    International Nuclear Information System (INIS)

    El-Tayeb, N.S.M.; Yap, T.C.; Venkatesh, V.C.; Brevern, P.V.

    2009-01-01

    The potential of cryogenic effect on frictional behaviour of newly developed titanium alloy Ti-5Al-4V-0.6Mo-0.4Fe (Ti54) sliding against tungsten carbide was investigated and compared with conventional titanium alloy Ti6Al4V (Ti64). In this study, four models were developed to describe the interrelationship between the friction coefficient (response) and independent variables such as speed, load, and sliding distance (time). These variables were investigated using the design of experiments and utilization of the response surface methodology (RSM). By using this method, it was possible to study the effect of main and mixed (interaction) independent variables on the friction coefficient (COF) of both titanium alloys. Under cryogenic condition, the friction coefficient of both Ti64 and Ti54 behaved differently, i.e. an increase in the case of Ti64 and decrease in the case of Ti54. For Ti64, at higher levels of load and speed, sliding in cryogenic conditions produces relatively higher friction coefficients compared to those obtained in dry air conditions. On contrary, introduction of cryogenic fluid reduces the friction coefficients of Ti54 at all tested conditions of load, speed, and time. The established models demonstrated that the mixed effect of load/speed, time/speed, and load/time consistently decrease the COF of Ti54. However this was not the case for Ti64 whereas the COF increased up to 20% when the Ti64 was tested at higher levels of load and sliding time. Furthermore, the models indicated that interaction of loads and speeds was more effective for both Ti-alloy and have the most substantial influence on the friction. In addition, COF for both alloys behaved linearly with the speed but nonlinearly with the load.

  1. Superconducting magnets and cryogenics for the steady state superconducting tokamak SST-1

    International Nuclear Information System (INIS)

    Saxena, Y.C.

    2000-01-01

    SST-1 is a steady state superconducting tokamak for studying the physics of the plasma processes in tokamak under steady state conditions and to learn technologies related to the steady state operation of the tokamak. SST-1 will have superconducting magnets made from NbTi based conductors operating at 4.5 K temperature. The design of the superconducting magnets and the cryogenic system of SST-1 tokamak are described. (author)

  2. Proceedings of the 26th International Cryogenic Engineering Conference - International Cryogenic Material Conference 2016

    Science.gov (United States)

    Datta, T. S.; Sharma, R. G.; Kar, S.

    2017-02-01

    International Conference ICEC 26 - ICMC 2016 was organized at New Delhi, India during March 7-11, 2016. Previous conference ICEC25-ICMC 2014 was held at the University of Twente, The Netherlands in July 2014. Next Conference ICEC 27- ICMC 2018 will be held at Oxford, UK during September 3-7, 2018 1. Introduction This is a biennial international conference on cryogenic engineering and cryogenics materials organized by the International Cryogenic Engineering Committee and the International Cryogenic Material Committee. For some years, the host country has been alternating between Europe and Asia. The present conference was held at the Manekshaw Convention Centre, New Delhi, India during March 7-11, 2016 and hosted jointly by the Indian Cryogenics Council (ICC) and the Inter-University Accelerator Centre (IUAC), New Delhi. Put all together as many as 547 persons participated in the conference. Out of these 218 were foreign delegates coming from 25 countries and the rest from India. 2. Inaugural Session & Course Lectures The pre conference short course lectures on “Cryocoolers” and “Superconducting Materials for Power Applications” were organized on 7th March. Cryocooler course was given jointly by Dr. Chao Wang from M/s. Cryomech, USA and Prof. Milind Atrey from IIT Bombay, India. The Course on Superconducting Materials was given by Prof. Venkat Selvamanickam from the University of Houston, USA. The conference was inaugurated in the morning of March 8th in a typical Indian tradition and in the presence of the Chief Guest, Dr. R Chidambaram (Principle Scientific Adviser to Govt. of India), Guest of Honour, Prof. H Devaraj (Vice Chairman University Grant Commission), Prof Marcel ter Brake ( Chair, ICEC Board), Prof. Wilfried Goldacker (Chair, ICMC board), Dr. D Kanjilal (Director IUAC), Dr R K Bhandari, (President, Indian Cryogenic Council ). Dr. T S Datta, Chair Local Organizing Committee coordinated the proceedings of the inaugural function. 3. Technical

  3. Large Cryogenic Infrastructure for LHC Superconducting Magnet and Cryogenic Component Tests: Layout, Commissioning and Operational Experience

    International Nuclear Information System (INIS)

    Calzas, C.; Chanat, D.; Knoops, S.; Sanmarti, M.; Serio, L.

    2004-01-01

    The largest cryogenic test facility at CERN, located at Zone 18, is used to validate and to test all main components working at cryogenic temperature in the LHC (Large Hadron Collider) before final installation in the machine tunnel. In total about 1300 main dipoles, 400 main quadrupoles, 5 RF-modules, eight 1.8 K refrigeration units will be tested in the coming years.The test facility has been improved and upgraded over the last few years and the first 18 kW refrigerator for the LHC machine has been added to boost the cryogenic capacity for the area via a 25,000 liter liquid helium dewar. The existing 6 kW refrigerator, used for the LHC Test String experiments, will also be employed to commission LHC cryogenic components.We report on the design and layout of the test facility as well as the commissioning and the first 10,000 hours operational experience of the test facility and the 18 kW LHC refrigerator

  4. Bayesian analogy with relational transformations.

    Science.gov (United States)

    Lu, Hongjing; Chen, Dawn; Holyoak, Keith J

    2012-07-01

    How can humans acquire relational representations that enable analogical inference and other forms of high-level reasoning? Using comparative relations as a model domain, we explore the possibility that bottom-up learning mechanisms applied to objects coded as feature vectors can yield representations of relations sufficient to solve analogy problems. We introduce Bayesian analogy with relational transformations (BART) and apply the model to the task of learning first-order comparative relations (e.g., larger, smaller, fiercer, meeker) from a set of animal pairs. Inputs are coded by vectors of continuous-valued features, based either on human magnitude ratings, normed feature ratings (De Deyne et al., 2008), or outputs of the topics model (Griffiths, Steyvers, & Tenenbaum, 2007). Bootstrapping from empirical priors, the model is able to induce first-order relations represented as probabilistic weight distributions, even when given positive examples only. These learned representations allow classification of novel instantiations of the relations and yield a symbolic distance effect of the sort obtained with both humans and other primates. BART then transforms its learned weight distributions by importance-guided mapping, thereby placing distinct dimensions into correspondence. These transformed representations allow BART to reliably solve 4-term analogies (e.g., larger:smaller::fiercer:meeker), a type of reasoning that is arguably specific to humans. Our results provide a proof-of-concept that structured analogies can be solved with representations induced from unstructured feature vectors by mechanisms that operate in a largely bottom-up fashion. We discuss potential implications for algorithmic and neural models of relational thinking, as well as for the evolution of abstract thought. Copyright 2012 APA, all rights reserved.

  5. Crows spontaneously exhibit analogical reasoning.

    Science.gov (United States)

    Smirnova, Anna; Zorina, Zoya; Obozova, Tanya; Wasserman, Edward

    2015-01-19

    Analogical reasoning is vital to advanced cognition and behavioral adaptation. Many theorists deem analogical thinking to be uniquely human and to be foundational to categorization, creative problem solving, and scientific discovery. Comparative psychologists have long been interested in the species generality of analogical reasoning, but they initially found it difficult to obtain empirical support for such thinking in nonhuman animals (for pioneering efforts, see [2, 3]). Researchers have since mustered considerable evidence and argument that relational matching-to-sample (RMTS) effectively captures the essence of analogy, in which the relevant logical arguments are presented visually. In RMTS, choice of test pair BB would be correct if the sample pair were AA, whereas choice of test pair EF would be correct if the sample pair were CD. Critically, no items in the correct test pair physically match items in the sample pair, thus demanding that only relational sameness or differentness is available to support accurate choice responding. Initial evidence suggested that only humans and apes can successfully learn RMTS with pairs of sample and test items; however, monkeys have subsequently done so. Here, we report that crows too exhibit relational matching behavior. Even more importantly, crows spontaneously display relational responding without ever having been trained on RMTS; they had only been trained on identity matching-to-sample (IMTS). Such robust and uninstructed relational matching behavior represents the most convincing evidence yet of analogical reasoning in a nonprimate species, as apes alone have spontaneously exhibited RMTS behavior after only IMTS training. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Reactions induced by low energy electrons in cryogenic films

    International Nuclear Information System (INIS)

    Bass, A.D.; Sanche, L.

    2003-01-01

    We review recent research on reactions (including dissociation) initiated by low-energy electron bombardment of monolayer and multilayer molecular solids at cryogenic temperatures. With incident electrons of energies below 20 eV, dissociation is observed by the electron stimulated desorption (ESD) of anions from target films and is attributed to the processes of dissociative electron attachment (DEA) and to dipolar dissociation. It is shown that DEA to condensed molecules is sensitive to environmental factors such as the identity of co-adsorbed species and film morphology. The effects of image-charge induced polarization on cross-sections for DEA to CH3Cl are also discussed. Taking as examples, the electron-induced production of CO within multilayer films of methanol and acetone, it is shown that the detection of electronic excited states by high resolution electron energy loss spectroscopy can be used to monitor electron beam damage. In particular, the incident energy dependence of the CO indicates that below 19 eV, dissociation proceeds via the decay of transient negative ions (TNI) into electronically excited dissociative states. The electron induced dissociation of biomolecular targets is also considered, taking as examples the ribose analog tetrahydrofuran and DNA bases adenine and thymine, cytosine and guanine. The ESD of anions from such films also show dissociation via the formation of TNI. In multilayer molecular solids, fragment species resulting from dissociation, may react with neighboring molecules, as is demonstrated in anion ESD measurements from films containing O 2 and various hydrocarbon molecules. X-ray photoelectron spectroscopy measurements reported for electron irradiated monolayers of H 2 O and CF 4 on a Si - H passivated surface further show that DEA is an important initial step in the electron-induced chemisorption of fragment species

  7. The effect of cryogenic cooling and minimum quantity lubrication on end milling of titanium alloy Ti-6Al-4V

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyung Hee; Yang, Gi Dong; Lee, Dong Yoon; Kim, Tae Gon; Lee, Seok Woo [Korea Institute of Industrial Technology, Cheonan (Korea, Republic of); Suhaimi, M. A. [Universiti Teknologi Malaysia, Johor Bahru (Malaysia); Kim, Dong Won [Chonbuk National University, Jeonju (Korea, Republic of)

    2015-11-15

    The cooling down of cutting temperature in machining is very important for the improvement of tool life, especially when dealing with work materials that have low thermal conductivity such as titanium alloy. In this study designed to investigate the machining performance of a variety of cooling methods, cryogenic, Minimum quantity lubrication (MQL), and flood cooling are performed on solid end milling of titanium alloy, Ti-6Al-4V. In particular, the effect of internal and external spray methods on cryogenic machining is analyzed with a specially designed liquid nitrogen spraying system by evaluating tool wear and cutting force at cutting conditions. The cutting force is also analyzed for tool breakage detection. As a result, the combination of MQL and internal cryogenic cooling improves tool life by up to 32% compared to conventional cooling methods. The cutting force is also reduced significantly by this combination of cooling and lubrication strategy of side end milling.

  8. The effect of cryogenic cooling and minimum quantity lubrication on end milling of titanium alloy Ti-6Al-4V

    International Nuclear Information System (INIS)

    Park, Kyung Hee; Yang, Gi Dong; Lee, Dong Yoon; Kim, Tae Gon; Lee, Seok Woo; Suhaimi, M. A.; Kim, Dong Won

    2015-01-01

    The cooling down of cutting temperature in machining is very important for the improvement of tool life, especially when dealing with work materials that have low thermal conductivity such as titanium alloy. In this study designed to investigate the machining performance of a variety of cooling methods, cryogenic, Minimum quantity lubrication (MQL), and flood cooling are performed on solid end milling of titanium alloy, Ti-6Al-4V. In particular, the effect of internal and external spray methods on cryogenic machining is analyzed with a specially designed liquid nitrogen spraying system by evaluating tool wear and cutting force at cutting conditions. The cutting force is also analyzed for tool breakage detection. As a result, the combination of MQL and internal cryogenic cooling improves tool life by up to 32% compared to conventional cooling methods. The cutting force is also reduced significantly by this combination of cooling and lubrication strategy of side end milling.

  9. Automatic control of cryogenic wind tunnels

    Science.gov (United States)

    Balakrishna, S.

    1989-01-01

    Inadequate Reynolds number similarity in testing of scaled models affects the quality of aerodynamic data from wind tunnels. This is due to scale effects of boundary-layer shock wave interaction which is likely to be severe at transonic speeds. The idea of operation of wind tunnels using test gas cooled to cryogenic temperatures has yielded a quantrum jump in the ability to realize full scale Reynolds number flow similarity in small transonic tunnels. In such tunnels, the basic flow control problem consists of obtaining and maintaining the desired test section flow parameters. Mach number, Reynolds number, and dynamic pressure are the three flow parameters that are usually required to be kept constant during the period of model aerodynamic data acquisition. The series of activity involved in modeling, control law development, mechanization of the control laws on a microcomputer, and the performance of a globally stable automatic control system for the 0.3-m Transonic Cryogenic Tunnel (TCT) are discussed. A lumped multi-variable nonlinear dynamic model of the cryogenic tunnel, generation of a set of linear control laws for small perturbation, and nonlinear control strategy for large set point changes including tunnel trajectory control are described. The details of mechanization of the control laws on a 16 bit microcomputer system, the software features, operator interface, the display and safety are discussed. The controller is shown to provide globally stable and reliable temperature control to + or - 0.2 K, pressure to + or - 0.07 psi and Mach number to + or - 0.002 of the set point value. This performance is obtained both during large set point commands as for a tunnel cooldown, and during aerodynamic data acquisition with intrusive activity like geometrical changes in the test section such as angle of attack changes, drag rake movements, wall adaptation and sidewall boundary-layer removal. Feasibility of the use of an automatic Reynolds number control mode with

  10. A Scanning Quantum Cryogenic Atom Microscope

    Science.gov (United States)

    Lev, Benjamin

    Microscopic imaging of local magnetic fields provides a window into the organizing principles of complex and technologically relevant condensed matter materials. However, a wide variety of intriguing strongly correlated and topologically nontrivial materials exhibit poorly understood phenomena outside the detection capability of state-of-the-art high-sensitivity, high-resolution scanning probe magnetometers. We introduce a quantum-noise-limited scanning probe magnetometer that can operate from room-to-cryogenic temperatures with unprecedented DC-field sensitivity and micron-scale resolution. The Scanning Quantum Cryogenic Atom Microscope (SQCRAMscope) employs a magnetically levitated atomic Bose-Einstein condensate (BEC), thereby providing immunity to conductive and blackbody radiative heating. The SQCRAMscope has a field sensitivity of 1.4 nT per resolution-limited point (2 um), or 6 nT / Hz1 / 2 per point at its duty cycle. Compared to point-by-point sensors, the long length of the BEC provides a naturally parallel measurement, allowing one to measure nearly one-hundred points with an effective field sensitivity of 600 pT / Hz1 / 2 each point during the same time as a point-by-point scanner would measure these points sequentially. Moreover, it has a noise floor of 300 pT and provides nearly two orders of magnitude improvement in magnetic flux sensitivity (down to 10- 6 Phi0 / Hz1 / 2) over previous atomic probe magnetometers capable of scanning near samples. These capabilities are for the first time carefully benchmarked by imaging magnetic fields arising from microfabricated wire patterns and done so using samples that may be scanned, cryogenically cooled, and easily exchanged. We anticipate the SQCRAMscope will provide charge transport images at temperatures from room to \\x9D4K in unconventional superconductors and topologically nontrivial materials.

  11. Cryogen spray cooling during laser tissue welding.

    Science.gov (United States)

    Fried, N M; Walsh, J T

    2000-03-01

    Cryogen cooling during laser tissue welding was explored as a means of reducing lateral thermal damage near the tissue surface and shortening operative time. Two centimetre long full-thickness incisions were made on the epilated backs of guinea pigs, in vivo. India ink was applied to the incision edges then clamps were used to appose the edges. A 4 mm diameter beam of 16 W, continuous-wave, 1.06 microm, Nd:YAG laser radiation was scanned over the incisions, producing approximately 100 ms pulses. There was a delay of 2 s between scans. The total irradiation time was varied from 1-2 min. Cryogen was delivered to the weld site through a solenoid valve in spurt durations of 20, 60 and 100 ms. The time between spurts was either 2 or 4 s, corresponding to one spurt every one or two laser scans. Histology and tensile strength measurements were used to evaluate laser welds. Total irradiation times were reduced from 10 min without surface cooling to under 1 min with surface cooling. The thermal denaturation profile showed less denaturation in the papillary dermis than in the mid-dermis. Welds created using optimized irradiation and cooling parameters had significantly higher tensile strengths (1.7 +/- 0.4 kg cm(-2)) than measured in the control studies without cryogen cooling (1.0 +/- 0.2 kg cm(-2)) (p laser welding results in increased weld strengths while reducing thermal damage and operative times. Long-term studies will be necessary to determine weld strengths and the amount of scarring during wound healing.

  12. Using Composite Materials in a Cryogenic Pump

    Science.gov (United States)

    Batton, William D.; Dillard, James E.; Rottmund, Matthew E.; Tupper, Michael L.; Mallick, Kaushik; Francis, William H.

    2008-01-01

    Several modifications have been made to the design and operation of an extended-shaft cryogenic pump to increase the efficiency of pumping. In general, the efficiency of pumping a cryogenic fluid is limited by thermal losses which is itself caused by pump inefficiency and leakage of heat through the pump structure. A typical cryogenic pump includes a drive shaft and two main concentric static components (an outer pressure containment tube and an intermediate static support tube) made from stainless steel. The modifications made include replacement of the stainless-steel drive shaft and the concentric static stainless-steel components with components made of a glass/epoxy composite. The leakage of heat is thus reduced because the thermal conductivity of the composite is an order of magnitude below that of stainless steel. Taking advantage of the margin afforded by the decrease in thermal conductivity, the drive shaft could be shortened to increase its effective stiffness, thereby increasing the rotordynamic critical speeds, thereby further making it possible to operate the pump at a higher speed to increase pumping efficiency. During the modification effort, an analysis revealed that substitution of the shorter glass/epoxy shaft for the longer stainless-steel shaft was not, by itself, sufficient to satisfy the rotordynamic requirements at the desired increased speed. Hence, it became necessary to increase the stiffness of the composite shaft. This stiffening was accomplished by means of a carbon-fiber-composite overwrap along most of the length of the shaft. Concomitantly with the modifications described thus far, it was necessary to provide for joining the composite-material components with metallic components required by different aspects of the pump design. An adhesive material formulated specially to bond the composite and metal components was chosen as a means to satisfy these requirements.

  13. Cryogenic Scan Mechanism for Fourier Transform Spectrometer

    Science.gov (United States)

    Brasunas, John C.; Francis, John L.

    2011-01-01

    A compact and lightweight mechanism has been developed to accurately move a Fourier transform spectrometer (FTS) scan mirror (a cube corner) in a near-linear fashion with near constant speed at cryogenic temperatures. This innovation includes a slide mechanism to restrict motion to one dimension, an actuator to drive the motion, and a linear velocity transducer (LVT) to measure the speed. The cube corner mirror is double-passed in one arm of the FTS; double-passing is required to compensate for optical beam shear resulting from tilting of the moving cube corner. The slide, actuator, and LVT are off-the-shelf components that are capable of cryogenic vacuum operation. The actuator drives the slide for the required travel of 2.5 cm. The LVT measures translation speed. A proportional feedback loop compares the LVT voltage with the set voltage (speed) to derive an error signal to drive the actuator and achieve near constant speed. When the end of the scan is reached, a personal computer reverses the set voltage. The actuator and LVT have no moving parts in contact, and have magnetic properties consistent with cryogenic operation. The unlubricated slide restricts motion to linear travel, using crossed roller bearings consistent with 100-million- stroke operation. The mechanism tilts several arc seconds during transport of the FTS mirror, which would compromise optical fringe efficiency when using a flat mirror. Consequently, a cube corner mirror is used, which converts a tilt into a shear. The sheared beam strikes (at normal incidence) a flat mirror at the end of the FTS arm with the moving mechanism, thereby returning upon itself and compensating for the shear

  14. Cryogenic instrumentation for ITER magnets

    Science.gov (United States)

    Poncet, J.-M.; Manzagol, J.; Attard, A.; André, J.; Bizel-Bizellot, L.; Bonnay, P.; Ercolani, E.; Luchier, N.; Girard, A.; Clayton, N.; Devred, A.; Huygen, S.; Journeaux, J.-Y.

    2017-02-01

    Accurate measurements of the helium flowrate and of the temperature of the ITER magnets is of fundamental importance to make sure that the magnets operate under well controlled and reliable conditions, and to allow suitable helium flow distribution in the magnets through the helium piping. Therefore, the temperature and flow rate measurements shall be reliable and accurate. In this paper, we present the thermometric chains as well as the venturi flow meters installed in the ITER magnets and their helium piping. The presented thermometric block design is based on the design developed by CERN for the LHC, which has been further optimized via thermal simulations carried out by CEA. The electronic part of the thermometric chain was entirely developed by the CEA and will be presented in detail: it is based on a lock-in measurement and small signal amplification, and also provides a web interface and software to an industrial PLC. This measuring device provides a reliable, accurate, electromagnetically immune, and fast (up to 100 Hz bandwidth) system for resistive temperature sensors between a few ohms to 100 kΩ. The flowmeters (venturi type) which make up part of the helium mass flow measurement chain have been completely designed, and manufacturing is on-going. The behaviour of the helium gas has been studied in detailed thanks to ANSYS CFX software in order to obtain the same differential pressure for all types of flowmeters. Measurement uncertainties have been estimated and the influence of input parameters has been studied. Mechanical calculations have been performed to guarantee the mechanical strength of the venturis required for pressure equipment operating in nuclear environment. In order to complete the helium mass flow measurement chain, different technologies of absolute and differential pressure sensors have been tested in an applied magnetic field to identify equipment compatible with the ITER environment.

  15. The oxycoal process with cryogenic oxygen supply

    Science.gov (United States)

    Kather, Alfons; Scheffknecht, Günter

    2009-09-01

    Due to its large reserves, coal is expected to continue to play an important role in the future. However, specific and absolute CO2 emissions are among the highest when burning coal for power generation. Therefore, the capture of CO2 from power plants may contribute significantly in reducing global CO2 emissions. This review deals with the oxyfuel process, where pure oxygen is used for burning coal, resulting in a flue gas with high CO2 concentrations. After further conditioning, the highly concentrated CO2 is compressed and transported in the liquid state to, for example, geological storages. The enormous oxygen demand is generated in an air-separation unit by a cryogenic process, which is the only available state-of-the-art technology. The generation of oxygen and the purification and liquefaction of the CO2-enriched flue gas consumes significant auxiliary power. Therefore, the overall net efficiency is expected to be lowered by 8 to 12 percentage points, corresponding to a 21 to 36% increase in fuel consumption. Oxygen combustion is associated with higher temperatures compared with conventional air combustion. Both the fuel properties as well as limitations of steam and metal temperatures of the various heat exchanger sections of the steam generator require a moderation of the temperatures during combustion and in the subsequent heat-transfer sections. This is done by means of flue gas recirculation. The interdependencies among fuel properties, the amount and the temperature of the recycled flue gas, and the resulting oxygen concentration in the combustion atmosphere are investigated. Expected effects of the modified flue gas composition in comparison with the air-fired case are studied theoretically and experimentally. The different atmosphere resulting from oxygen-fired combustion gives rise to various questions related to firing, in particular, with regard to the combustion mechanism, pollutant reduction, the risk of corrosion, and the properties of the fly

  16. The oxycoal process with cryogenic oxygen supply.

    Science.gov (United States)

    Kather, Alfons; Scheffknecht, Günter

    2009-09-01

    Due to its large reserves, coal is expected to continue to play an important role in the future. However, specific and absolute CO2 emissions are among the highest when burning coal for power generation. Therefore, the capture of CO2 from power plants may contribute significantly in reducing global CO2 emissions. This review deals with the oxyfuel process, where pure oxygen is used for burning coal, resulting in a flue gas with high CO2 concentrations. After further conditioning, the highly concentrated CO2 is compressed and transported in the liquid state to, for example, geological storages. The enormous oxygen demand is generated in an air-separation unit by a cryogenic process, which is the only available state-of-the-art technology. The generation of oxygen and the purification and liquefaction of the CO2-enriched flue gas consumes significant auxiliary power. Therefore, the overall net efficiency is expected to be lowered by 8 to 12 percentage points, corresponding to a 21 to 36% increase in fuel consumption. Oxygen combustion is associated with higher temperatures compared with conventional air combustion. Both the fuel properties as well as limitations of steam and metal temperatures of the various heat exchanger sections of the steam generator require a moderation of the temperatures during combustion and in the subsequent heat-transfer sections. This is done by means of flue gas recirculation. The interdependencies among fuel properties, the amount and the temperature of the recycled flue gas, and the resulting oxygen concentration in the combustion atmosphere are investigated. Expected effects of the modified flue gas composition in comparison with the air-fired case are studied theoretically and experimentally. The different atmosphere resulting from oxygen-fired combustion gives rise to various questions related to firing, in particular, with regard to the combustion mechanism, pollutant reduction, the risk of corrosion, and the properties of the fly

  17. Piezoresistive silicon pressure sensors in cryogenic environment

    Science.gov (United States)

    Kahng, Seun K.; Chapman, John J.

    1989-01-01

    This paper presents data on low-temperature measurements of silicon pressure sensors. It was found that both the piezoresistance coefficients and the charge-carrier mobility increase with decreasing temperature. For lightly doped semiconductor materials, the density of free charge carriers decreases with temperature and can freeze out eventually. However, the effect of carrier freeze-out can be minimized by increasing the impurity content to higher levels, at which the temperature dependency of piezoresistance coefficients is reduced. An impurity density of 1 x 10 to the 19th/cu cm was found to be optimal for cryogenic applications of pressure sensor dies.

  18. SPICA sub-Kelvin cryogenic chains

    Science.gov (United States)

    Duband, L.; Duval, J. M.; Luchier, N.; Prouve, T.

    2012-04-01

    SPICA, a Japanese led mission, is part of the JAXA future science program and is planned for launch in 2018. SPICA will perform imaging and spectroscopic observations in the mid- and far-IR waveband, and is developing instrumentation spanning the 5-400 μm range. The SPICA payload features several candidate instruments, some of them requiring temperature down to 50 mK. This is currently the case for SAFARI, a core instrument developed by a European-based consortium, and BLISS proposed by CALTECH/JPL in the US. SPICA's distinctive feature is to actively cool its telescope to below 6 K. In addition, SPICA is a liquid cryogen free satellite and all the cooling will be provided by radiative cooling (L2 orbit) down to 30 K and by mechanical coolers for lower temperatures. The satellite will launch warm and slowly equilibrate to its operating temperatures once in orbit. This warm launch approach makes it possible to eliminate a large liquid cryogen tank and to use the mass saved to launch a large diameter telescope (3.2 m). This 4 K cooled telescope significantly reduces its own thermal radiation, offering superior sensitivity in the infrared region. The cryogenic system that enables this warm launch/cooled telescope concept is a key issue of the mission. This cryogenic chain features a number of cooling stages comprising passive radiators, Stirling coolers and several Joule Thomson loops, offering cooling powers at typically 20, 4.5, 2.5 and 1.7 K. The SAFARI and BLISS detectors require cooling to temperatures as low as 50 mK. The instrument coolers will be operated from these heat sinks. They are composed of a small demagnetization refrigerator (ADR) pre cooled by either a single or a double sorption cooler, respectively for SAFARI and BLISS. The BLISS cooler maintains continuous cooling at 300 mK and thus suppresses the thermal equilibrium time constant of the large focal plane. These hybrid architectures allow designing low weight coolers able to reach 50 mK. Because

  19. Ferromagnetic Josephson Junctions for Cryogenic Memory

    Science.gov (United States)

    Niedzielski, Bethany M.; Gingrich, Eric C.; Khasawneh, Mazin A.; Loloee, Reza; Pratt, William P., Jr.; Birge, Norman O.

    2015-03-01

    Josephson junctions containing ferromagnetic materials are of interest for both scientific and technological purposes. In principle, either the amplitude of the critical current or superconducting phase shift across the junction can be controlled by the relative magnetization directions of the ferromagnetic layers in the junction. Our approach concentrates on phase control utilizing two junctions in a SQUID geometry. We will report on efforts to control the phase of junctions carrying either spin-singlet or spin-triplet supercurrent for cryogenic memory applications. Supported by Northorp Grumman Corporation and by IARPA under SPAWAR Contract N66001-12-C-2017.

  20. Cryogenic semiconductor high-intensity radiation monitors

    International Nuclear Information System (INIS)

    Palmieri, V.G.; Bell, W.H.; Borer, K.; Casagrande, L.; Da Via, C.; Devine, S.R.H.; Dezillie, B.; Esposito, A.; Granata, V.; Hauler, F.; Jungermann, L.; Li, Z.; Lourenco, C.; Niinikoski, T.O.; Shea, V. O'; Ruggiero, G.; Sonderegger, P.

    2003-01-01

    This paper describes a novel technique to monitor high-intensity particle beams by means of a semiconductor detector. It consists of cooling a semiconductor detector down to cryogenic temperature to suppress the thermally generated leakage current and to precisely measure the integrated ionization signal. It will be shown that such a device provides very good linearity and a dynamic range wider than is possible with existing techniques. Moreover, thanks to the Lazarus effect, extreme radiation hardness can be achieved providing in turn absolute intensity measurements against precise calibration of the device at low beam flux

  1. The cryogenic source of slow monochromatic positrons

    International Nuclear Information System (INIS)

    Meshkov, I.N.; Pavlov, V.N.; Sidorin, A.O.; Yakovenko, S.L.

    2008-01-01

    The cryogenic source of slow monochromatic positrons based on the 22 Na isotope has been designed and constructed at JINR. Positrons emitted from radioactive source 22 Na have a very broad energy spectrum up to 0.5 MeV. To generate monochromatic beam of slow positrons the solid neon is used as a moderator. The solid neon allows forming slow positron beam of the energy of 1.2 eV at the spectrum width of 1 eV. The efficiency of moderation is 1 % of total positron flux

  2. ngVLA Cryogenic Subsystem Concept

    Science.gov (United States)

    Wootten, Al; Urbain, Denis; Grammer, Wes; Durand, S.

    2018-01-01

    The VLA’s success over 35 years of operations stems in part from dramatically upgraded components over the years. The time has come to build a new array to lead the radio astronomical science into its next 40 years. To accomplish that, a next generation VLA (ngVLA) is envisioned to have 214 antennas with diameters of 18m. The core of the array will be centered at the current VLA location, but the arms will extend out to 1000km.The VLA cryogenic subsystem equipment and technology have remained virtually unchanged since the early 1980s. While adequate for a 27-antenna array, scaling the current system for an array of 214 antennas would be prohibitively expensive in terms of operating cost and maintenance. The overall goal is to limit operating cost to within three times the current level, despite having 8 times the number of antennas. To help realize this goal, broadband receivers and compact feeds will be utilized to reduce both the size and number of cryostats required. The current baseline front end concept calls for just two moderately-sized cryostats for the entire 1.2-116 GHz frequency range, as opposed to 8 in the VLA.For the ngVLA cryogenics, our objective is a well-optimized and efficient system that uses state-of-the-art technology to minimize per-antenna power consumption and maximize reliability. Application of modern technologies, such as variable-speed operation for the scroll compressors and cryocooler motor drives, allow the cooling capacity of the system to be dynamically matched to thermal loading in each cryostat. Significantly, power savings may be realized while the maintenance interval of the cryocoolers is also extended.Finally, a receiver designed to minimize thermal loading can produce savings directly translating to lower operating cost when variable-speed drives are used. Multi-layer insulation (MLI) on radiation shields and improved IR filters on feed windows can significantly reduce heat loading.Measurements done on existing cryogenic

  3. Cryogenic transimpedance amplifier for micromechanical capacitive sensors.

    Science.gov (United States)

    Antonio, D; Pastoriza, H; Julián, P; Mandolesi, P

    2008-08-01

    We developed a cryogenic transimpedance amplifier that works at a broad range of temperatures, from room temperature down to 4 K. The device was realized with a standard complementary metal oxide semiconductor 1.5 mum process. Measurements of current-voltage characteristics, open-loop gain, input referred noise current, and power consumption are presented as a function of temperature. The transimpedance amplifier has been successfully applied to sense the motion of a polysilicon micromechanical oscillator at low temperatures. The whole device is intended to serve as a magnetometer for microscopic superconducting samples.

  4. Renovation of the Sissi cryogenic system

    International Nuclear Information System (INIS)

    Anon.

    1999-01-01

    SISSI (high current superconductor secondary ion source) involved a cryo-generator operating in a close circuit when the whole system was put in service in 1994. Since then the cryo-generator has proved to be insufficiently reliable. A new cryogenic system based on an external liquid helium supply has been designed. The helium transfer lines are surrounded by a shield at liquid nitrogen temperature and numerous layers of super-insulators in order to have minimum thermal losses. The installation was integrated to SISSI in summer 1998 and after the first operating period some improvements concerning the cooling procedure have to be considered. (A.C.)

  5. Thin Cryogenic X-ray Windows

    CERN Document Server

    Niinikoski, T O; Davenport, M; Elias, N; Aune, S; Franz, J

    2009-01-01

    We describe the construction and tests of cryogenic X-ray windows of 47 mm diameter made of 15 ìm thick polypropylene foil glued on a UHV flange and supported with a strongback mesh machined by electro-erosion. These hermetic windows of the solar axion telescope of the CAST experiment at CERN withstand the static and dynamic pressures of the buffer gas that are normally below 130 mbar, but may reach 1.2 bar when the magnet quenches. They were tested at 60 K up to 3.5 bar static pressure without permanent deformation.

  6. Explosive Boiling of Superheated Cryogenic Liquids

    CERN Document Server

    Baidakov, V G

    2007-01-01

    The monograph is devoted to the description of the kinetics of spontaneous boiling of superheated liquefied gases and their solutions. Experimental results are given on the temperature of accessible superheating, the limits of tensile strength of liquids due to processes of cavitation and the rates of nucleation of classical and quantum liquids. The kinetics of evolution of the gas phase is studied in detail for solutions of cryogenic liquids and gas-saturated fluids. The properties of the critical clusters (bubbles of critical sizes) of the newly evolving gas phase are analyzed for initial st

  7. Cryogen free low temperature sample environment for neutron scattering experiments

    International Nuclear Information System (INIS)

    Kirichek, O; Evans, B E; Down, R B E; Bowden, Z A

    2009-01-01

    Recent increase in liquid helium cost caused by global helium supply problems rose significant concern about affordability of conventional cryogenic equipment. Luckily the progress in cryo-cooler technology offers a new generation of cryogenic systems with significantly reduced consumption and in some cases nearly complete elimination of cryogens. These cryogen-free systems also offer the advantage of operational simplicity and require less space than conventional cryogen-cooled systems. The ISIS facility carries on an internal development program intended to substitute gradually all conventional cryogenic systems with cryogen free systems preferably based on pulse tube refrigerators. A unique feature of this cryo-cooler is the absence of cold moving parts. This considerably reduces vibrations and increases the reliability of the cold head. The program includes few development projects which are aiming to deliver range of cryogen free equipment including top-loading cryostat, superconducting magnets and dilution refrigerators. Here we are going to describe the design of these systems and discuss the results of prototypes testing.

  8. Cryogenic storage tank with built-in pump

    International Nuclear Information System (INIS)

    Zwick, E.B.

    1984-01-01

    A cryogenic storage tank with a built-in pump for pumping cryogen directly from the primary storage container consistent with low boil-off losses of cryogen has an outer vessel, an inner vessel and an evacuated insulation space therebetween. A pump mounting tube assembly extends into the interior of the inner vessel and includes an inner pump mounting tube and an outer pump mounting tube joined at their lower rims to define an insulating jacket between the two tubes. The inner pump mounting tube is affixed at its upper end to the outer vessel while the outer pump mounting tube is affixed at its upper end to the inner vessel. The inner pump mounting tube defines a relatively long heat path into the cryogenic container and is itself insulated from the liquid cryogen by a pocket of trapped gas formed within the inner pump mounting tube by heated cryogen. A pump may be introduced through the inner pump mounting tube and is also insulated against contact with liquid cryogen by the trapped gas such that only the lowermost end of the pump is immersed in cryogen thereby minimizing heat leakage into the tank

  9. Commissioning of cryogenic system for China Spallation Neutron Source

    Science.gov (United States)

    Ye, Bin; He, Chongchao; Li, Na; Ding, Meiying; Wang, Yaqiong; Yu, Zhang; He, Kun

    2017-12-01

    China Spallation Neutron Source(CSNS) cryogenic system provides supercritical cryogenic hydrogen to neutron moderators, including a helium refrigerator, hydrogen loop and hydrogen safety equipment. The helium refrigerator is provided by Linde with cooling capacity of 2200 W at 20 K. Hydrogen loop system mainly includes cryogenic hydrogen pipes, hydrogen circulator cold-box and accumulator cold-box. Cryogenic hydrogen pump, ortho-para convertor, helium-hydrogen heat-exchanger, hydrogen heater and accumulator are integrated in hydrogen circulation cold-box, and accumulator cold-box. Hydrogen safety equipment includes safety valves, rupture disk, hydrogen sensor, flame detector and other equipment to ensure that cryogenic system in dangerous situations will go down, vents, or takes other measures. The cryogenic system commissioning work includes four steps. First, in order to test the refrigerating capacity of refrigerator, when acceptance testing, refrigerator internal heater was used as thermal load. Second, using simulation load as heat load of moderator, hydrogen loop use helium instead of hydrogen, and cooled down to 20 K, then re-warming and test the leak detection of hydrogen loop system. Third, base on the step 2, using hydrogen as working medium, and optimized the control logic. Forth, cryogenic system with the moderators joint commissioning. Now, cryogenic system is connected with the moderators, and the forth step will be carried out in the near future.

  10. Endpoint distinctiveness facilitates analogical mapping in pigeons.

    Science.gov (United States)

    Hagmann, Carl Erick; Cook, Robert G

    2015-03-01

    Analogical thinking necessitates mapping shared relations across two separate domains. We investigated whether pigeons could learn faster with ordinal mapping of relations across two physical dimensions (circle size & choice spatial position) relative to random mapping of these relations. Pigeons were trained to relate six circular samples of different sizes to horizontally positioned choice locations in a six alternative matching-to-sample task. Three pigeons were trained in a mapped condition in which circle size mapped directly onto choice spatial position. Three other pigeons were trained in a random condition in which the relations between size and choice position were arbitrarily assigned. The mapped group showed an advantage over the random group in acquiring this task. In a subsequent second phase, relations between the dimensions were ordinally reversed for the mapped group and re-randomized for the random group. There was no difference in how quickly matching accuracy re-emerged in the two groups, although the mapped group eventually performed more accurately. Analyses suggested this mapped advantage was likely due to endpoint distinctiveness and the benefits of proximity errors during choice responding rather than a conceptual or relational advantage attributable to the common or ordinal mapping of the two dimensions. This potential difficulty in mapping relations across dimensions may limit the pigeons' capacity for more advanced types of analogical reasoning. This article is part of a Special Issue entitled: Tribute to Tom Zentall. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Endpoint Distinctiveness Facilitates Analogical Mapping in Pigeons

    Science.gov (United States)

    Hagmann, Carl Erick; Cook, Robert G.

    2015-01-01

    Analogical thinking necessitates mapping shared relations across two separate domains. We investigated whether pigeons could learn faster with ordinal mapping of relations across two physical dimensions (circle size & choice spatial position) relative to random mapping of these relations. Pigeons were trained to relate six circular samples of different sizes to horizontally positioned choice locations in a six alternative matching-to-sample task. Three pigeons were trained in a mapped condition in which circle size mapped directly onto choice spatial position. Three other pigeons were trained in a random condition in which the relations between size and choice position were arbitrarily assigned. The mapped group showed an advantage over the random group in acquiring this task. In a subsequent second phase, reassignment, relations between the dimensions were ordinally reversed for the mapped group and re-randomized for the random group. There was no difference in how quickly matching accuracy re-emerged in the two groups, although the mapped group eventually performed more accurately. Analyses suggested this mapped advantage was likely due endpoint distinctiveness and the benefits of proximity errors during choice responding rather than a conceptual or relational advantage attributable to the common or ordinal map of the two dimensions. This potential difficulty in mapping relations across dimensions may limit the pigeons’ capacity for more advanced types of analogical reasoning. PMID:25447511

  12. Research of the cold shield in cryogenic liquid storage

    Science.gov (United States)

    Chen, L. B.; Zheng, J. P.; Wu, X. L.; Cui, C.; Zhou, Y.; Wang, J. J.

    2017-12-01

    To realize zero boil-off storage of cryogenic liquids, a cryocooler that can achieve a temperature below the boiling point temperature of the cryogenic liquid is generally needed. Taking into account that the efficiency of the cryocooler will be higher at a higher operating temperature, a novel thermal insulation system using a sandwich container filled with cryogenic liquid with a higher boiling point as a cold radiation shield between the cryogenic tank and the vacuum shield in room temperature is proposed to reduce the electricity power consumption. A two-stage cryocooler or two separate cryocoolers are adopted to condense the evaporated gas from the cold shield and the cryogenic tank. The calculation result of a 55 liter liquid hydrogen tank with a liquid nitrogen shield shows that only 14.4 W of electrical power is needed to make all the evaporated gas condensation while 121.7 W will be needed without the liquid nitrogen shield.

  13. Infrared detectors and test technology of cryogenic camera

    Science.gov (United States)

    Yang, Xiaole; Liu, Xingxin; Xing, Mailing; Ling, Long

    2016-10-01

    Cryogenic camera which is widely used in deep space detection cools down optical system and support structure by cryogenic refrigeration technology, thereby improving the sensitivity. Discussing the characteristics and design points of infrared detector combined with camera's characteristics. At the same time, cryogenic background test systems of chip and detector assembly are established. Chip test system is based on variable cryogenic and multilayer Dewar, and assembly test system is based on target and background simulator in the thermal vacuum environment. The core of test is to establish cryogenic background. Non-uniformity, ratio of dead pixels and noise of test result are given finally. The establishment of test system supports for the design and calculation of infrared systems.

  14. A heat exchanger analogy of automotive paint ovens

    International Nuclear Information System (INIS)

    Rao, Preetham P.

    2013-01-01

    Computational prediction of vehicle temperatures in an automotive paint oven is essential to predict paint quality and manufacturability. The complex geometry of vehicles, varying scales in the flow, transient nature of the process, and the tightly coupled conjugate heat transfer render the numerical models computationally very expensive. Here, a novel, simplified model of the oven is developed using an analogy to a three-stream cross flow heat exchanger that transfers heat from air to a series of moving bodies and supporting carriers. The analogous heat exchanger equations are developed and solved numerically. Steady state Computational Fluid Dynamics (CFD) simulations are carried out to model the flow field and to extract the heat transfer coefficients around the body and carriers. The air temperature distribution from the CFD models is used as a boundary condition in the analogous model. Correction coefficients are used in the analogy to take care of various assumptions. These are determined from existing test data. The same corrections are used to predict air temperatures for a modified configuration of the oven and a different vehicle. The method can be used to conduct control volume analysis of ovens to determine energy efficiency, and to study new vehicle or oven designs. -- Highlights: • Analogy of an automotive paint oven as a three stream cross flow heat exchanger. • The three streams are vehicle bodies, carriers and hot air. • Convection coefficients and inlet air stream temperatures from steady CFD simulations. • Analogy useful for overall energy efficiency analysis of conveyor ovens in general

  15. Analog circuit design art, science and personalities

    CERN Document Server

    Williams, Jim

    1991-01-01

    This book is far more than just another tutorial or reference guide - it's a tour through the world of analog design, combining theory and applications with the philosophies behind the design process. Readers will learn how leading analog circuit designers approach problems and how they think about solutions to those problems. They'll also learn about the `analog way' - a broad, flexible method of thinking about analog design tasks.A comprehensive and useful guide to analog theory and applications. Covers visualizing the operation of analog circuits. Looks at how to rap

  16. Cryogenic Fluid Management Technology for Moon and Mars Missions

    Science.gov (United States)

    Doherty, Michael P.; Gaby, Joseph D.; Salerno, Louis J.; Sutherlin, Steven G.

    2010-01-01

    In support of the U.S. Space Exploration Policy, focused cryogenic fluid management technology efforts are underway within the National Aeronautics and Space Administration. Under the auspices of the Exploration Technology Development Program, cryogenic fluid management technology efforts are being conducted by the Cryogenic Fluid Management Project. Cryogenic Fluid Management Project objectives are to develop storage, transfer, and handling technologies for cryogens to support high performance demands of lunar, and ultimately, Mars missions in the application areas of propulsion, surface systems, and Earth-based ground operations. The targeted use of cryogens and cryogenic technologies for these application areas is anticipated to significantly reduce propellant launch mass and required on-orbit margins, to reduce and even eliminate storage tank boil-off losses for long term missions, to economize ground pad storage and transfer operations, and to expand operational and architectural operations at destination. This paper organizes Cryogenic Fluid Management Project technology efforts according to Exploration Architecture target areas, and discusses the scope of trade studies, analytical modeling, and test efforts presently underway, as well as future plans, to address those target areas. The target areas are: liquid methane/liquid oxygen for propelling the Altair Lander Ascent Stage, liquid hydrogen/liquid oxygen for propelling the Altair Lander Descent Stage and Ares V Earth Departure Stage, liquefaction, zero boil-off, and propellant scavenging for Lunar Surface Systems, cold helium and zero boil-off technologies for Earth-Based Ground Operations, and architecture definition studies for long term storage and on-orbit transfer and pressurization of LH2, cryogenic Mars landing and ascent vehicles, and cryogenic production via in situ resource utilization on Mars.

  17. Integrated Circuits for Analog Signal Processing

    CERN Document Server

    2013-01-01

      This book presents theory, design methods and novel applications for integrated circuits for analog signal processing.  The discussion covers a wide variety of active devices, active elements and amplifiers, working in voltage mode, current mode and mixed mode.  This includes voltage operational amplifiers, current operational amplifiers, operational transconductance amplifiers, operational transresistance amplifiers, current conveyors, current differencing transconductance amplifiers, etc.  Design methods and challenges posed by nanometer technology are discussed and applications described, including signal amplification, filtering, data acquisition systems such as neural recording, sensor conditioning such as biomedical implants, actuator conditioning, noise generators, oscillators, mixers, etc.   Presents analysis and synthesis methods to generate all circuit topologies from which the designer can select the best one for the desired application; Includes design guidelines for active devices/elements...

  18. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel

    2017-01-01

    This textbook is appropriate for use in graduate-level curricula in analog-to-digital conversion, as well as for practicing engineers in need of a state-of-the-art reference on data converters. It discusses various analog-to-digital conversion principles, including sampling, quantization, reference generation, nyquist architectures and sigma-delta modulation. This book presents an overview of the state of the art in this field and focuses on issues of optimizing accuracy and speed, while reducing the power level. This new, third edition emphasizes novel calibration concepts, the specific requirements of new systems, the consequences of 22-nm technology and the need for a more statistical approach to accuracy. Pedagogical enhancements to this edition include additional, new exercises, solved examples to introduce all key, new concepts and warnings, remarks and hints, from a practitioner’s perspective, wherever appropriate. Considerable background information and practical tips, from designing a PCB, to lay-o...

  19. Cryogenic refractive index of Heraeus homosil glass

    Science.gov (United States)

    Miller, Kevin H.; Quijada, Manuel A.; Leviton, Douglas B.

    2017-08-01

    This paper reports measurements of the refractive index of Homosil (Heraeus) over the wavelength range of 0.34—3.16 μm and temperature range of 120—335 K. These measurements were performed by using the Cryogenic High Accuracy Refraction Measuring System (CHARMS) facility at the NASA's Goddard Space Flight Center. These measurements were in support of an integrated Structural-Thermal-Optical-Performance (STOP) model that was developed for a fieldwidened Michelson interferometer that is being built and tested for the High Spectral Resolution Lidar (HSRL) project at the NASA Langley Research Center (LaRC). The cryogenic refractive index measurements were required in order to account for the highly sensitive performance of the HSRL instrument to changes in refractive index with temperature, temperature gradients, thermal expansion, and deformation due to mounting stresses. A dense coverage of the absolute refractive index over the aforementioned wavelength and temperature ranges was used to determine the thermo-optic coefficient (dn/dT) and dispersion relation (dn/dλ) as a function of wavelength and temperature. Our measurements of Homosil will be compared with measurements of other glasses from the fused silica family studied in CHARMS as well as measurements reported elsewhere in the literature.

  20. Cryogenic Silicon Microstrip Detector Modules for LHC

    CERN Document Server

    Perea-Solano, B

    2004-01-01

    CERN is presently constructing the LHC, which will produce collisions of 7 TeV protons in 4 interaction points at a design luminosity of 1034 cm-2 s-1. The radiation dose resulting from the operation at high luminosity will cause a serious deterioration of the silicon tracker performance. The state-of-art silicon microstrip detectors can tolerate a fluence of about 3 1014 cm-2 of hadrons or charged leptons. This is insufficient, however, for long-term operation in the central parts of the LHC trackers, in particular after the possible luminosity upgrade of the LHC. By operating the detectors at cryogenic temperatures the radiation hardness can be improved by a factor 10. This work proposes a cryogenic microstrip detector module concept which has the features required for the microstrip trackers of the upgraded LHC experiments at CERN. The module can hold an edgeless sensor, being a good candidate for improved luminosity and total cross-section measurements in the ATLAS, CMS and TOTEM experiments. The design o...

  1. SiPM properties at cryogenic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Biroth, Maik; Achenbach, Patrick; Thomas, Andreas [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, Mainz (Germany); Downie, Evangeline [George Washington University, DC (United States); Collaboration: A2-Collaboration

    2015-07-01

    At the electron accelerator Mainzer Mikrotron (MAMI) an active target build of polarizable scintillators will be operated at approximately 25 mK. To read out the scintillation light, the photodetectors have to withstand cryogenic temperatures of 4 K and high count rates. Therefore the properties of different types of silicon photomultipliers (SiPMs) were studied at cryogenic temperatures. In liquid nitrogen at 77 K, problems with quenching in Hamamatsu SiPMs and with the protective epoxy layer covering Zecotek SiPMs were observed. Tests with one Zecotek SiPM were successful after removal of the epoxy layer in liquid helium at 4 K and no after-pulses could be observed. Fundamental parameters like break-down voltage, single-pixel gain, crosstalk probability and the dark-count rate were measured and compared to room temperature. The photon detection efficiency was estimated by SiPMs response to short LED pulses. All these parameters were extracted by curve-fitting of SiPM charge spectra with a new analytical function.

  2. Neutron Detection with a Cryogenic Spectrometer

    CERN Document Server

    Bell, Z W; Cristy, S S; Lamberti, V E

    2003-01-01

    Cryogenic calorimeters are used for x-ray detection because of their exquisite energy resolution and have found application in x-ray astronomy, and the search for dark matter. These devices operate by detecting the heat pulse produced by ionization in an absorber cooled to temperatures below 1 K. Such temperatures are needed to lower the absorber's heat capacity to the point that the deposition of even a few eV results in a measurable temperature excursion. Typical absorbers for dark matter measurements are massive Si or Ge crystals, and, with Ge, have achieved a resolution of 650 eV at 10 keV. Chow, et al., report the measurement of the 60 keV emission from sup 2 sup 4 sup 1 Am with 230 eV resolution using a superconducting tin absorber. Cunningham, et al., also using a superconducting tin absorber, have recently reported a four-fold improvement over Chow. With such results being reported from the x- and gamma-ray world it is natural to examine the possibilities for cryogenic neutron spectroscopy. Such a det...

  3. Advanced ACTPol Cryogenic Detector Arrays and Readout

    Science.gov (United States)

    Henderson, S. W.; Allison, R.; Austermann, J.; Baildon, T.; Battaglia, N.; Beall, J. A.; Becker, D.; De Bernardis, F.; Bond, J. R.; Calabrese, E.; Choi, S. K.; Coughlin, K. P.; Crowley, K. T.; Datta, R.; Devlin, M. J.; Duff, S. M.; Dunkley, J.; Dünner, R.; van Engelen, A.; Gallardo, P. A.; Grace, E.; Hasselfield, M.; Hills, F.; Hilton, G. C.; Hincks, A. D.; Hloẑek, R.; Ho, S. P.; Hubmayr, J.; Huffenberger, K.; Hughes, J. P.; Irwin, K. D.; Koopman, B. J.; Kosowsky, A. B.; Li, D.; McMahon, J.; Munson, C.; Nati, F.; Newburgh, L.; Niemack, M. D.; Niraula, P.; Page, L. A.; Pappas, C. G.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Sehgal, N.; Sherwin, B. D.; Sievers, J. L.; Simon, S. M.; Spergel, D. N.; Staggs, S. T.; Stevens, J. R.; Thornton, R.; Van Lanen, J.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-08-01

    Advanced ACTPol is a polarization-sensitive upgrade for the 6 m aperture Atacama Cosmology Telescope, adding new frequencies and increasing sensitivity over the previous ACTPol receiver. In 2016, Advanced ACTPol will begin to map approximately half the sky in five frequency bands (28-230 GHz). Its maps of primary and secondary cosmic microwave background anisotropies—imaged in intensity and polarization at few arcminute-scale resolution—will enable precision cosmological constraints and also a wide array of cross-correlation science that probes the expansion history of the universe and the growth of structure via gravitational collapse. To accomplish these scientific goals, the Advanced ACTPol receiver will be a significant upgrade to the ACTPol receiver, including four new multichroic arrays of cryogenic, feedhorn-coupled AlMn transition edge sensor polarimeters (fabricated on 150 mm diameter wafers); a system of continuously rotating meta-material silicon half-wave plates; and a new multiplexing readout architecture which uses superconducting quantum interference devices and time division to achieve a 64-row multiplexing factor. Here we present the status and scientific goals of the Advanced ACTPol instrument, emphasizing the design and implementation of the Advanced ACTPol cryogenic detector arrays.

  4. Cryogenic setup for trapped ion quantum computing.

    Science.gov (United States)

    Brandl, M F; van Mourik, M W; Postler, L; Nolf, A; Lakhmanskiy, K; Paiva, R R; Möller, S; Daniilidis, N; Häffner, H; Kaushal, V; Ruster, T; Warschburger, C; Kaufmann, H; Poschinger, U G; Schmidt-Kaler, F; Schindler, P; Monz, T; Blatt, R

    2016-11-01

    We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120 dB reduction of 50 Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield. The cryostat design incorporates vibration isolation to avoid decoherence of optical qubits due to the motion of the cryostat. We measure vibrations of the cryostat of less than ±20 nm over 2 s. In addition to the cryogenic apparatus, we describe the setup required for an operation with 40 Ca + and 88 Sr + ions. The instability of the laser manipulating the optical qubits in 40 Ca + is characterized by yielding a minimum of its Allan deviation of 2.4 ⋅ 10 -15 at 0.33 s. To evaluate the performance of the apparatus, we trapped 40 Ca + ions, obtaining a heating rate of 2.14(16) phonons/s and a Gaussian decay of the Ramsey contrast with a 1/e-time of 18.2(8) ms.

  5. Experimental investigation of cryogenic oscillating heat pipes

    Science.gov (United States)

    Jiao, A.J.; Ma, H.B.; Critser, J.K.

    2010-01-01

    A novel cryogenic heat pipe, oscillating heat pipe (OHP), which consists of an 4 × 18.5 cm evaporator, a 6 × 18.5 cm condenser, and 10 cm length of adiabatic section, has been developed and experimental characterization conducted. Experimental results show that the maximum heat transport capability of the OHP reached 380W with average temperature difference of 49 °C between the evaporator and condenser when the cryogenic OHP was charged with liquid nitrogen at 48% (v/v) and operated in a horizontal direction. The thermal resistance decreased from 0.256 to 0.112 while the heat load increased from 22.5 to 321.8 W. When the OHP was operated at a steady state and an incremental heat load was added to it, the OHP operation changed from a steady state to an unsteady state until a new steady state was reached. This process can be divided into three regions: (I) unsteady state; (II) transient state; and (III) new steady state. In the steady state, the amplitude of temperature change in the evaporator is smaller than that of the condenser while the temperature response keeps the same frequency both in the evaporator and the condenser. The experimental results also showed that the amplitude of temperature difference between the evaporator and the condenser decreased when the heat load increased. PMID:20585410

  6. Modelling and control of large cryogenic refrigerator

    International Nuclear Information System (INIS)

    Bonne, Francois

    2014-01-01

    This manuscript is concern with both the modeling and the derivation of control schemes for large cryogenic refrigerators. The particular case of those which are submitted to highly variable pulsed heat load is studied. A model of each object that normally compose a large cryo-refrigerator is proposed. The methodology to gather objects model into the model of a subsystem is presented. The manuscript also shows how to obtain a linear equivalent model of the subsystem. Based on the derived models, advances control scheme are proposed. Precisely, a linear quadratic controller for warm compression station working with both two and three pressures state is derived, and a predictive constrained one for the cold-box is obtained. The particularity of those control schemes is that they fit the computing and data storage capabilities of Programmable Logic Controllers (PLC) with are well used in industry. The open loop model prediction capability is assessed using experimental data. Developed control schemes are validated in simulation and experimentally on the 400W1.8K SBT's cryogenic test facility and on the CERN's LHC warm compression station. (author) [fr

  7. The DAΦNE cryogenic system

    International Nuclear Information System (INIS)

    Modena, M.

    1997-12-01

    The DAΦNE Project utilises superconductivity technology for a total of six superconducting magnets: the two Experiment magnets (KLOE and FINUDA) and the four Compensator Solenoid magnets needed to compensate the magnetic effect of the Experiment magnets on the electron and positron beams. This effect, on beams of 510 MeV (nominal DAΦNE Energy), is expected to be relevant, especially with the aim of achieving a very high luminosity, which is the main target of the Project. The KLOE superconducting magnet has two possible working positions: the first in the DAΦNE Hall, when the Experiment will be in operation, and the second one in the KLOE Assembly Hall. This second position is the first to be utilised for the KLOE magnet Acceptance Test and magnetic field mapping, prior to the mounting of all the experimental apparatus inside the magnet. This note intends to present the DAΦNE Cryogenic System and how the authors have converged to the definition of a common Cryogenic System compatible with all the six superconducting magnets

  8. Analogies between antiferromagnets and antiferroelectrics

    International Nuclear Information System (INIS)

    Enz, C.P.; Matthias, B.T.

    1980-01-01

    Ferro- and antiferromagnetism in the Laves phase TiBesub(2-x) Cusub(x) occurs for 0.1 4 H 2 PO 4 and its solid solutions with TlH 2 PO 4 and with the ferroelectric KH 2 PO 4 are discussed as function of deuteration and of pressure. Another analogy as function of pressure is established with the antiferroelectric perovskite PbZrO 3 . (author)

  9. Novel phosphanucleoside analogs of dideoxynucleosides

    Czech Academy of Sciences Publication Activity Database

    Páv, Ondřej; Buděšínský, Miloš; Rosenberg, Ivan

    2017-01-01

    Roč. 73, č. 34 (2017), s. 5220-5228 ISSN 0040-4020 R&D Projects: GA ČR(CZ) GA17-12703S; GA ČR GA13-26526S; GA MZd NV15-31604A Institutional support: RVO:61388963 Keywords : phosphanucleoside * nucleoside analog * ring-closing metathesis * stereoselective hydroboration * chiral resolution Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 2.651, year: 2016

  10. Advances in cryogenic engineering. Volume 27 - Proceedings of the Cryogenic Engineering Conference, San Diego, CA, August 11-14, 1981

    Science.gov (United States)

    Fast, R. W.

    Applications of superconductivity are considered, taking into account MHD and fusion, generators, transformers, transmission lines, magnets for physics, cryogenic techniques, electrtronics, and aspects of magnet stability. Advances related to heat transfer in He I are discussed along with subjects related to theat transfer in He II, refrigeration of superconducting systems, refrigeration and liquefaction, dilution and magnetic refrigerators, refrigerators for space applications, mass transfer and flow phenomena, and the properties of fluids. Developments related to cryogenic applications are also explored, giving attention to bulk storage and transfer of cryogenic fluids, liquefied natural gas operations, space science and technology, and cryopumping. Topics related to cryogenic instrumentation and controls include the production and use of high grade silicon diode temperature sensors, the choice of strain gages for use in a large superconducting alternator, microprocessor control of cryogenic pressure, and instrumentation, data acquisition and reduction for a large spaceborne helium dewar. For individual items see A83-43221 to A83-43250

  11. Electrostatic analogy for symmetron gravity

    Science.gov (United States)

    Ogden, Lillie; Brown, Katherine; Mathur, Harsh; Rovelli, Kevin

    2017-12-01

    The symmetron model is a scalar-tensor theory of gravity with a screening mechanism that suppresses the effect of the symmetron field at high densities characteristic of the Solar System and laboratory scales but allows it to act with gravitational strength at low density on the cosmological scale. We elucidate the screening mechanism by showing that in the quasistatic Newtonian limit there are precise analogies between symmetron gravity and electrostatics for both strong and weak screening. For strong screening we find that large dense bodies behave in a manner analogous to perfect conductors in electrostatics. Based on this analogy we find that the symmetron field exhibits a lightning rod effect wherein the field gradients are enhanced near the ends of pointed or elongated objects. An ellipsoid placed in a uniform symmetron gradient is shown to experience a torque. By symmetry there is no gravitational torque in this case. Hence this effect unmasks the symmetron and might serve as the basis for future laboratory experiments. The symmetron force between a point mass and a large dense body includes a component corresponding to the interaction of the point mass with its image in the larger body. None of these effects have counterparts in the Newtonian limit of Einstein gravity. We discuss the similarities between symmetron gravity and the chameleon model as well as the differences between the two.

  12. Cryogenic Photogrammetry and Radiometry for the James Webb Space Telescope Microshutters

    Science.gov (United States)

    Chambers, Victor J.; Morey, Peter A.; Zukowski, Barbara J.; Kutyrev, Alexander S.; Collins, Nicholas R.

    2012-01-01

    The James Webb Space Telescope (JWST) relies on several innovations to complete its five year mission. One vital technology is microshutters, the programmable field selectors that enable the Near Infrared Spectrometer (NIRSpec) to perform multi-object spectroscopy. Mission success depends on acquiring spectra from large numbers of galaxies by positioning shutter slits over faint targets. Precise selection of faint targets requires field selectors that are both high in contrast and stable in position. We have developed test facilities to evaluate microshutter contrast and alignment stability at their 35K operating temperature. These facilities used a novel application of image registration algorithms to obtain non-contact, sub-micron measurements in cryogenic conditions. The cryogenic motion of the shutters was successfully characterized. Optical results also demonstrated that shutter contrast far exceeds the NIRSpec requirements. Our test program has concluded with the delivery of a flight-qualified field selection subsystem to the NIRSpec bench.

  13. Cryogenic and thermal design for the Space Infrared Telescope Facility (SIRTF)

    Science.gov (United States)

    Lee, J. H.; Brooks, W. F.

    1984-01-01

    The 1-meter class cryogenically cooled Space Infrared Telescope Facility (SIRTF) planned by NASA, is scheduled for a 1992 launch. SIRTF would be deployed from the Shuttle, and placed into a sun synchronous polar orbit of 700 km. The facility has been defined for a mission with a minimum initial lifetime of one year in orbit with mission extension that could be made possible through in-orbit servicing of the superfluid helium cryogenic system, and use of a thermal control system. The superfluid dewar would use an orbital disconnect system for the tank supports, and vapor cooling of the barrel baffle. The transient analysis of the design shows that the superfluid helium tank with no active feedback comes within temperature requirements for the nominal orbital aperture heat load, quiescent instrument, and chopper conditions.

  14. Energy Efficiency of large Cryogenic Systems: the LHC Case and Beyond

    CERN Document Server

    Claudet, S; Ferlin, G; Lebrun, P; Tavian, L; Wagner, U

    2013-01-01

    Research infrastructures for high-energy and nuclear physics, nuclear fusion and production of high magnetic fields are increasingly based on applied superconductivity and associated cryogenics in their quest for scientific breakthroughs at affordable capital and operation costs, a condition for their acceptance and sustained funding by society. The thermodynamic penalty for operating at low temperature makes energy efficiency a key requirement for their large cryogenic systems, from conceptual design to procurement, construction and operation. Meeting this requirement takes a combined approach on several fronts in parallel: management of heat loads and sizing of cooling duties, distribution of cooling power matching the needs of the superconducting devices, efficient production of refrigeration, optimal control resting on precise instrumentation and diagnostics, as well as a targeted industrial procurement policy. The case of the Large Hadron Collider (LHC) at CERN is presented. Potential improvements for fu...

  15. A camac-based intelligent subsystem for ATLAS example application: cryogenic monitoring and control

    International Nuclear Information System (INIS)

    Pardo, R.; Kawarasaki, Y.; Wasniewski, K.

    1985-01-01

    A subunit of the CAMAC accelerator control system of ATLAS for monitoring and, eventually, controlling the cryogenic refrigeration and distribution facility is under development. This development is the first application of a philosophy of distributed intelligence which will be applied throughout the ATLAS control system. The control concept is that of an intelligent subunit of the existing ATLAS CAMAC control highway. A single board computer resides in an auxiliary crate controller which allows access to all devices within the crate. The local SBC can communicate to the host over the CAMAC highway via a protocol involving the use of memory in the SBC which can be accessed from the host in a DMA mode. This provides a mechanism for global communications, such as for alarm conditions, as well as allowing the cryogenic system to respond to the demands of the accelerator system

  16. Characteristics of GaAs/AlGaAs-doped channel MISFET's at cryogenic temperatures

    International Nuclear Information System (INIS)

    Laskar, J.; Kolodzey, J.; Ketterson, A.A.; Adesida, I.; Cho, A.Y.

    1990-01-01

    The authors present high-frequency measurements at cryogenic temperatures to 125 K of 0.3-μm gate length GaAs/Al 0.3 Ga 0.7 As metal insulator semiconductor field-effect transistors (MISFET's) with a doped channel. Experimental results demonstrate significant improvement in performance including an increase in the maximum frequency of oscillation f max from 70 to 81 GHz and an increase in the unity current gain cutoff frequency f T from 46 to 57 GHz. Independently determined decreases in electron mobility and increases in electron velocity under similar conditions lead to the conclusion that carrier velocity and not mobility controls transport in these devices. These results show the high-speed potential of doped channel MISFET's at both room temperature and cryogenic temperatures

  17. The method for assurance to operational safety of cryogenics equipment through definite maintenance

    International Nuclear Information System (INIS)

    Anghel, Vasile

    2004-01-01

    The present paper reports about a method of ensuring operational safety of cryogenics equipment through specific maintenance measures which imply a definite concept of maintainability and operational reliability, methods of maintenance, necessary logistic and necessary personnel. The stages of the concept should succeed in a logical order and must be based on detailed analyses of the process of maintenance. The method starts from the operation conditions of cryogenic equipment in nuclear regime. Thus maintenance policy must be well defined within the boundaries of the nuclear plant through definition of coherent objectives and responsibility delegation for the personnel implied in maintenance activity. This method ensures performance in maintenance and an efficient feedback from equipment analysis. (author)

  18. The Control System for the Cryogenics in the LHC Tunnel [First Experience and Improvements

    CERN Document Server

    Gomes, P; Casas, J; Fluder, C; Fortescue, E; Le Roux, P; Penacoba, G; Pezzetti, M; Soubiran, M; Tovar, A; Zwalinski, L

    2010-01-01

    The Large Hadron Collider (LHC) was commissioned at CERN and started operation with beams in 2008. Several months of operation in nominal cryogenic conditions have triggered an optimisation of the process functional analysis. This lead to a few revisions of the control logic, which were realised on-the-fly. During the 2008-09 shut-down, and in order to enhance the safety, availability and operability of the LHC cryogenics, a major rebuild of the logic and several hardware modifications were implemented. The databases, containing instruments and controls in-formation, are being rationalized; the automatic tool, that extracts data for the control software, is being simplified. This paper describes the main improvements and sug-gests perspectives of further developments.

  19. Cryogenic thermometer calibration system using a helium cooling loop and a temperature controller [for LHC magnets

    CERN Document Server

    Chanzy, E; Thermeau, J P; Bühler, S; Joly, C; Casas-Cubillos, J; Balle, C

    1998-01-01

    The IPN-Orsay and CERN are designing in close collaboration a fully automated cryogenic thermometer calibration facility which will calibrate in 3 years 10,000 cryogenic thermometers required for the Large Hadron Collider (LHC) operation. A reduced-scale model of the calibration facility has been developed, which enables the calibration of ten thermometers by comparison with two rhodium-iron standard thermometers in the 1.8 K to 300 K temperature range under vacuum conditions. The particular design, based on a helium cooling loop and an electrical temperature controller, gives good dynamic performances. This paper describes the experimental set-up and the data acquisition system. Results of experimental runs are also presented along with the estimated global accuracy for the calibration. (3 refs).

  20. Test Results of Selected Commercial DC/DC Converters under Cryogenic Temperatures - A Digest

    Science.gov (United States)

    Patterson, Richard; Hammoud, Ahmad

    2010-01-01

    DC/DC converters are widely used in space power systems in the areas of power management and distribution, signal conditioning, and motor control. Design of DC/DC converters to survive cryogenic temperatures will improve the power system performance, simplify design, and reduce development and launch costs. In this work, the performance of nine COTS modular, low-tomedium power DC/DC converters was investigated under cryogenic temperatures. The converters were evaluated in terms of their output regulation, efficiency, and input and output currents. At a given temperature, these properties were obtained at various input voltages and at different load levels. A summary on the performance of the tested converters was given. More comprehensive testing and in-depth analysis of performance under long-term exposure to extreme temperatures are deemed necessary to establish the suitability of these and other devices for use in the harsh environment of space exploration missions.

  1. ITER task T332a (1996) low-inventory cryogenic distillation tests

    International Nuclear Information System (INIS)

    Woodall, K.; Bellamy, D.

    1997-02-01

    The overall objective of this ITER task was to perform tests which would improve the accuracy of the ITER Isotope Separation System (ISS) tritium inventory estimates and to allow designers to lower the tritium and hydrogen inventory estimates. The work program was also designed to give a better understanding of cryogenic distillation hydraulics and provide information which would improve process control. The work program this year addressed the following specific task objectives. Measure the detailed hydraulics for deuterium/deuterium hydride mixtures in a cryogenic distillation column using Helipak C packing. Determine maximum vapour velocity, HETP and tritium and deuterium inventory data for a column that can be operated right up to flooding conditions. Determine if a proprietary surface treatment improves the wetting characteristics for hydrogen on stainless steel packing. Measure the isotope separation and inventory performance of a Helipak C column large enough to handle up to 45 mm. Investigate additional hydraulic effects in the reboiler and column. 7 refs., 7 figs

  2. CAMAC-based intelligent subsystem for ATLAS example application: cryogenic monitoring and control

    International Nuclear Information System (INIS)

    Pardo, R.; Kawarasaki, Y.; Wasniewski, K.

    1985-01-01

    A subunit of the CAMAC accelerator control system of ATLAS for monitoring and, eventually, controlling the cryogenic refrigeration and distribution facility is under development. This development is the first application of a philosophy of distributed intelligence which will be applied throughout the ATLAS control system. The control concept is that of an intelligent subunit of the existing ATLAS CAMAC control highway. A single board computer resides in an auxiliary crate controller which allows access to all devices within the crate. The local SBC can communicate to the host over the CAMAC highway via a protocol involving the use of memory in the SBC which can be accessed from the host in a DMA mode. This provides a mechanism for global communications, such as for alarm conditions, as well as allowing the cryogenic system to respond to the demands of the accelerator system

  3. Automatic control of NASA Langley's 0.3-meter cryogenic test facility

    Science.gov (United States)

    Thibodeaux, J. J.; Balakrishna, S.

    1980-01-01

    Experience during the past 6 years of operation of the 0.3-meter transonic cryogenic tunnel at the NASA Langley Research Center has shown that there are problems associated with efficient operation and control of cryogenic tunnels using manual control schemes. This is due to the high degree of process crosscoupling between the independent control variables (temperature, pressure, and fan drive speed) and the desired test condition (Mach number and Reynolds number). One problem has been the inability to maintain long-term accurate control of the test parameters. Additionally, the time required to change from one test condition to another has proven to be excessively long and much less efficient than desirable in terms of liquid nitrogen and electrical power usage. For these reasons, studies have been undertaken to: (1) develop and validate a mathematical model of the 0.3-meter cryogenic tunnel process, (2) utilize this model in a hybrid computer simulation to design temperature and pressure feedback control laws, and (3) evaluate the adequacy of these control schemes by analysis of closed-loop experimental data. This paper will present the results of these studies.

  4. The Development of Analogical Reasoning Processes.

    Science.gov (United States)

    Sternberg, Robert J.; Rifkin, Bathsheva

    1979-01-01

    Two experiments were conducted to test the generalizability to children of a theory of analogical reasoning processes, originally proposed for adults, and to examine the development of analogical reasoning processes in terms of five proposed sources of cognitive development. (MP)

  5. 16-channel analog store and multiplexer unit

    Energy Technology Data Exchange (ETDEWEB)

    Brossard, M; Kulka, Z [Clermont-Ferrand-2 Univ., 63 - Aubiere (France). Lab. de Physique Corpusculaire

    1979-03-15

    A 16-channel analog store and multiplexer unit is described. The unit enables storing and selection of analog information which is then digitally encoded by single ADC. This solution becomes economically attractive particularly in multidetector pulse height analysis systems.

  6. Experimental study on the thermal hydraulic performance of plate-fin heat exchangers for cryogenic applications

    Science.gov (United States)

    Jiang, Qingfeng; Zhuang, Ming; Zhang, Qiyong; Zhu, Zhigang; Geng, Maofei; Sheng, Linhai; Zhu, Ping

    2018-04-01

    Efficient and compact plate-fin heat exchangers are critical for large-scale helium liquefaction/refrigeration systems as they constitute major part in the cold box. This study experimentally explores the heat transfer and pressure drop behaviors of helium gas at low temperature in four types of plate-fin channels, namely offset-strip and perforated fins, with different geometrical parameters. A series of cryogenic experiments at approximately liquid nitrogen temperature are carried out to measure the Colburn j factors and Fanning friction f factors with a wide range of Reynolds number. Besides, to reveal the performance variations under different operating temperatures, comparative experiments respectively conducted at room temperature and liquid nitrogen temperature are implemented. The results show that in comparison with the performance data at room temperature, most of j factors are relatively smaller perhaps because the lower aluminum thermal conductivity and higher Prandtl Number at low temperature. Meanwhile, the f factors corresponding to cryogenic conditions exhibit slightly larger even though the core pressure drops show considerable reductions. In contrast to the calculated results from the frequently-used performance curves (Chen and Shen, 1993), the Root Mean Squared Errors of j and f values are correlated within 8.38% and 6.97% for one perforated fin core, 41.29% and 34.97% for three OSF cores, respectively. For OSFs, further comparisons with the previous empirical correlations from literatures are conducted to verify the accuracy of each correlation. Generally, most of the calculated results predict acceptably within the deviations of ±25% for the j factors, while the predicted results express relatively large deviations for the f factors. Therefore, it may be revealed that most of the existing correlations were not able to accurately predict the experimental data in consideration of the performance differences under realistic cryogenic operating

  7. Atheism and Analogy: Aquinas Against the Atheists

    OpenAIRE

    Linford, Daniel J.

    2014-01-01

    In the 13th century, Thomas Aquinas developed two models for how humans may speak of God - either by the analogy of proportion or by the analogy of proportionality. Aquinas's doctrines initiated a theological debate concerning analogy that spanned several centuries. In the 18th century, there appeared two closely related arguments for atheism which both utilized analogy for their own purposes. In this thesis, I show that one argument, articulated by the French materialist Paul-Henri Thiry Bar...

  8. Enhancing programming logic thinking using analogy mapping

    Science.gov (United States)

    Sukamto, R. A.; Megasari, R.

    2018-05-01

    Programming logic thinking is the most important competence for computer science students. However, programming is one of the difficult subject in computer science program. This paper reports our work about enhancing students' programming logic thinking using Analogy Mapping for basic programming subject. Analogy Mapping is a computer application which converts source code into analogies images. This research used time series evaluation and the result showed that Analogy Mapping can enhance students' programming logic thinking.

  9. Cooling pipeline disposing structure for large-scaled cryogenic structure

    International Nuclear Information System (INIS)

    Takahashi, Hiroyuki.

    1996-01-01

    The present invention concerns an electromagnetic force supporting structure for superconductive coils. As the size of a cryogenic structure is increased, since it takes much cooling time, temperature difference between cooling pipelines and the cryogenic structure is increased over a wide range, and difference of heat shrinkage is increased to increase thermal stresses. Then, in the cooling pipelines for a large scaled cryogenic structure, the cooling pipelines and the structure are connected by way of a thin metal plate made of a material having a heat conductivity higher than that of the material of the structure by one digit or more, and the thin metal plate is bent. The displacement between the cryogenic structure and the cooling pipelines caused by heat shrinkage is absorbed by the elongation/shrinkage of the bent structure of the thin metal plate, and the thermal stresses due to the displacement is reduced. In addition, the heat of the cryogenic structures is transferred by way of the thin metal plate. Then, the cooling pipelines can be secured to the cryogenic structure such that cooling by heat transfer is enabled by absorbing a great deviation or three dimensional displacement due to the difference of the temperature distribution between the cryogenic structure enlarged in the scale and put into the three dimensional shape, and the cooling pipelines. (N.H.)

  10. Process simulations for the LCLS-II cryogenic systems

    Science.gov (United States)

    Ravindranath, V.; Bai, H.; Heloin, V.; Fauve, E.; Pflueckhahn, D.; Peterson, T.; Arenius, D.; Bevins, M.; Scanlon, C.; Than, R.; Hays, G.; Ross, M.

    2017-12-01

    Linac Coherent Light Source II (LCLS-II), a 4 GeV continuous-wave (CW) superconducting electron linear accelerator, is to be constructed in the existing two mile Linac facility at the SLAC National Accelerator Laboratory. The first light from the new facility is scheduled to be in 2020. The LCLS-II Linac consists of thirty-five 1.3 GHz and two 3.9 GHz superconducting cryomodules. The Linac cryomodules require cryogenic cooling for the super-conducting niobium cavities at 2.0 K, low temperature thermal intercept at 5.5-7.5 K, and a thermal shield at 35-55 K. The equivalent 4.5 K refrigeration capacity needed for the Linac operations range from a minimum of 11 kW to a maximum of 24 kW. Two cryogenic plants with 18 kW of equivalent 4.5 K refrigeration capacity will be used for supporting the Linac cryogenic cooling requirements. The cryogenic plants are based on the Jefferson Lab’s CHL-II cryogenic plant design which uses the “Floating Pressure” design to support a wide variation in the cooling load. In this paper, the cryogenic process for the integrated LCLS-II cryogenic system and the process simulation for a 4.5 K cryoplant in combination with a 2 K cold compressor box, and the Linac cryomodules are described.

  11. Analogies and the 5E Model

    Science.gov (United States)

    Orgill, Mary Kay; Thomas, Megan

    2007-01-01

    Science classes are full of abstract or challenging concepts that are easier to understand if an analogy is used to illustrate the points. Effective analogies motivate students, clarify students' thinking, help students overcome misconceptions, and give students ways to visualize abstract concepts. When they are used appropriately, analogies can…

  12. Science Teachers' Analogical Reasoning

    Science.gov (United States)

    Mozzer, Nilmara Braga; Justi, Rosária

    2013-01-01

    Analogies can play a relevant role in students' learning. However, for the effective use of analogies, teachers should not only have a well-prepared repertoire of validated analogies, which could serve as bridges between the students' prior knowledge and the scientific knowledge they desire them to understand, but also know how to…

  13. The Micro-Category Account of Analogy

    Science.gov (United States)

    Green, Adam E.; Fugelsang, Jonathan A.; Kraemer, David J. M.; Dunbar, Kevin N.

    2008-01-01

    Here, we investigate how activation of mental representations of categories during analogical reasoning influences subsequent cognitive processing. Specifically, we present and test the central predictions of the "Micro-Category" account of analogy. This account emphasizes the role of categories in aligning terms for analogical mapping. In a…

  14. Commissioning of the Cryogenic Plant for the Cryogenic Storage Ring (CSR) at Heidelberg

    CERN Document Server

    von Hahn, R; Grieser, M; Haberstroh, C; Kaiser, D; Lange, M; Laux, F; Menk, S; Orlov, D A; Repnow, R; Sieber, T; Quack, H; Varju, J; Wolf A

    2009-01-01

    At the Max-Planck-Institute for Nuclear Physics in Heidelberg a next generation electrostatic storage ring for low velocity atomic and molecular ion beams is under construction. In contrast to existing electrostatic storage rings, the Cryogenic Storage Ring CSR will be cooled down to temperatures below 2 K. Thus acting as a large cryopump it will provide long storage times and, in addition, open a new field of quantum state controlled molecular physics due to a low heat radiation background from space-like environment. A concept for cooling the storage ring has been developed and is presently tested by means of a linear trap as a prototype with a length of 1/10 of the planned ring. A commercial refrigerator with 21 W at 2 K has been successfully commissioned and was connected to the prototype. This paper presents the status of the cryogenic plant after the commissioning and one year of operation.

  15. Cold atoms in a cryogenic environment

    International Nuclear Information System (INIS)

    Haslinger, S.

    2011-01-01

    The idea of quantum information processing attracts increasingly interest, where a complex collection of quantum objects and quantum bits are employed to find the ideal building blocks for quantum information systems. Hybrid quantum systems are therefore promising objects as they countervail the particular drawbacks of single quantum objects. Based on superconducting resonator technology, microwave coplanar waveguides provide a well suited interconnection for photons and solid-state quantum bits (qubits), extensively investigated in recent years. Since a quantum memory is presently missing in those electrical accessible circuit cavity quantum devices, connecting the fast processing in a solid sate device to the exceptional long coherence times in atomic ensembles, the presented work is focused to establish the technological foundations for the hybridization of such quantum systems. The microwave photons stored in a superconducting high finesse microwave resonator are therefore an ideal connection between the atom and the solid state quantum world. In the last decade, the miniaturization and integration of quantum optics and atomic physics manipulation techniques on to a single chip was successfully established. Such atom chips are capable of detailed quantum manipulation of ultra-cold atoms and provide a versatile platform to combine the manipulation techniques from atomic physics with the capability of nano-fabrication. In recent years several experiments succeeded in realization of superconducting atom chips in cryogenic environments which opens the road for integrating super-conductive microwave resonators to magnetically couple an atomic ensemble to photons stored in the coplanar high finesse cavity. This thesis presents the concept, design and experimental setup of two approaches to establish an atomic ensemble of rubidium atoms inside a cryogenic environment, based on an Electron beam driven alkali metal atom source for loading a magneto optical trap in a

  16. Evacuation apparatus with cryogenic pump and trap assembly

    International Nuclear Information System (INIS)

    Mahl, G.

    1980-01-01

    An evacuation apparatus comprising a vessel defining a vacuum chamber therein, vacuumizing means communicating with an opening to said vacuum chamber for selectively drawing a vacuum therein comprising cryogenic pump means disposed closely adjacent to said opening and defined by substantial cryogenically cooled trap surfaces for freezing-out water vapor from air evacuated from said vacuum chamber, said opening being common to said vacuum chamber and to said cryogenic pump means, valve means for selectively opening or closing the opening to said vacuum chamber and movable from a first position within said cryogenic pump means closing said opening to a second position within said cryogenic pump means directly exposing said vacuum chamber to said cryogenic pump means, through said opening, baffle means disposed closely adjacent to the opening to said vacuum chamber for providing substantial open communication to said vacuum chamber and for substantially preventing ingress of contaminants into said vacuum chamber, said baffle means being positioned to provide an optically dense view of said opening when viewed from a downstream side of said baffle means, and a plurality of longitudinally spaced and cryogenically cooled fins mounted in nested relationship within said baffle means and disposed in out-of-contact relationship therewith, said fins being positioned to provide an optically dense view of the downstream side of said baffle means when viewed from said openings. The cryogenic pump is adapted for use in an evacuation apparatus comprising a housing defining an opening to a vacuum chamber, a plurality of metallic plates defining a first chamber therein communicating with said vacuum chamber through said opening and further defining a second chamber at least partially surrounding said first chamber and adapted to be at least partially filled with a cryogenic liqui.d

  17. An fMRI investigation of cognitive stages in reasoning by analogy.

    Science.gov (United States)

    Krawczyk, Daniel C; McClelland, M Michelle; Donovan, Colin M; Tillman, Gail D; Maguire, Mandy J

    2010-06-25

    We compared reasoning about four-term analogy problems in the format (A:B::C: D) to semantic and perceptual control conditions that required matching without analogical mapping. We investigated distinct phases of the problem solving process divided into encoding, mapping/inference, and response. Using fMRI, we assessed the brain activation relevant to each of these phases with an emphasis on achieving a better understanding of analogical reasoning relative to these other matching conditions. We predicted that the analogical condition would involve the most cognitive effort in the encoding and mapping/inference phases, while the control conditions were expected to engage greater prefrontal cortex (PFC) activation at the response period. Results showed greater activation for the analogical condition relative to the control conditions at the encoding phase in several predominantly left lateralized and medial areas of the PFC. Similar results were observed for the mapping/inference phase, though this difference was limited to the left PFC and rostral PFC. The response phase resulted in the fastest and most accurate responses in the analogy condition relative to the control conditions. This was accompanied by greater processing within the left lateral and the medial PFC for the control conditions relative to the analogy condition, consistent with most of the cognitive processing of the analogy condition having occurred in the prior task phases. Overall we demonstrate that the left ventral and dorsal lateral, medial, and rostral PFC are important in both the encoding of relational information, mapping and inference processes, and verification of semantic and perceptual responses in four term analogical reasoning. Copyright 2010 Elsevier B.V. All rights reserved.

  18. Cryogenic system operating experience review for fusion applications

    International Nuclear Information System (INIS)

    Cadwallader, L.C.

    1992-01-01

    This report presents a review of cryogenic system operating experiences, from particle accelerator, fusion experiment, space research, and other applications. Safety relevant operating experiences and accident information are discussed. Quantitative order-of-magnitude estimates of cryogenic component failure rates and accident initiating event frequencies are presented for use in risk assessment, reliability, and availability studies. Safety concerns with cryogenic systems are discussed, including ozone formation, effects of spills, and modeling spill behavior. This information should be useful to fusion system designers and safety analysts, such as the team working on the International Thermonuclear Experimental Reactor design

  19. Thermohydrodynamic analysis of cryogenic liquid turbulent flow fluid film bearings

    Science.gov (United States)

    Andres, Luis San

    1993-01-01

    A thermohydrodynamic analysis is presented and a computer code developed for prediction of the static and dynamic force response of hydrostatic journal bearings (HJB's), annular seals or damper bearing seals, and fixed arc pad bearings for cryogenic liquid applications. The study includes the most important flow characteristics found in cryogenic fluid film bearings such as flow turbulence, fluid inertia, liquid compressibility and thermal effects. The analysis and computational model devised allow the determination of the flow field in cryogenic fluid film bearings along with the dynamic force coefficients for rotor-bearing stability analysis.

  20. Status of the Cryogenic System Commissioning at SNS

    CERN Document Server

    Casagrande, Fabio; Campisi, Isidoro E; Creel, Jonathan; Dixon, Kelly; Ganni, Venkatarao; Gurd, Pamela; Hatfield, Daniel; Howell, Matthew; Knudsen, Peter; Stout, Daniel; Strong, William

    2005-01-01

    The Spallation Neutron Source (SNS) is under construction at Oak Ridge National Laboratory. The cold section of the Linac consists of 81 superconducting radio frequency cavities cooled to 2.1K by a 2400 Watt cryogenic refrigeration system. The major cryogenic system components include warm helium compressors with associated oil removal and gas management, 4.5K cold box, 7000L liquid helium dewar, 2.1K cold box (consisting of 4 stages of cold compressors), gaseous helium storage, helium purification and gas impurity monitoring system, liquid nitrogen storage and the cryogenic distribution transfer line system. The overall system commissioning strategy and status will be presented.

  1. Experimental study on friction and wear behaviour of amorphous carbon coatings for mechanical seals in cryogenic environment

    Science.gov (United States)

    Wang, Jianlei; Jia, Qian; Yuan, Xiaoyang; Wang, Shaopeng

    2012-10-01

    The service life and the reliability of contact mechanical seal are directly affected by the wear of seal pairs (rotor vs. stator), especially under the cryogenic environment in liquid rocket engine turbopumps. Because of the lower friction and wear rate, amorphous carbon (a-C) coatings are the promising protective coatings of the seal pairs for contact mechanical seal. In this paper, a-C coatings were deposited on 9Cr18 by pulsed DC magnetron sputtering. The tribological performances of the specimen were tested under three sealed fluid conditions (air, water and liquid nitrogen). The results show that the coatings could endure the cryogenic temperature while the friction coefficients decrease with the increased contact load. Under the same contact condition, the friction coefficient of the a-C coatings in liquid nitrogen is higher than that in water and that they are in air. The friction coefficients of the a-C coatings in liquid nitrogen range from 0.10 to 0.15. In the cryogenic environment, the coatings remain their low specific wear rates (0.9 × 10-6 to 1.8 × 10-6 mm3 N-1 m-1). The results provide an important reference for designing a water lubricated bearing or a contact mechanical seal under the cryogenic environment that is both reliable and has longevity.

  2. Are all analogies created equal? Prefrontal cortical functioning may predict types of analogical reasoning.

    Science.gov (United States)

    Chrysikou, Evangelia G; Thompson-Schill, Sharon L

    2010-06-01

    Abstract The proposed theory can account for analogies based on learned relationships between elements in the source and target domains. However, its explanatory power regarding the discovery of new relationships during analogical reasoning is limited. We offer an alternative perspective for the role of PFC in analogical thought that may better address different types of analogical mappings.

  3. Cryogenic air separation: the last twenty years

    International Nuclear Information System (INIS)

    Grenier, M.; Petit, P.

    1986-01-01

    In the last 20 years cryogenic air separation plant sizes have increased from 150 tons per day to 2800 tons per day. Progressively reversing heat exchangers have replaced regenerators. However, with this arrangement, the quantity of pure product output is limited to about 50% of the air input. With the appearance on the market of molecular sieve, another arrangement was developed, which allows one to produce a combined pure product flow equivalent to 85% of the air input. Recently, there has been a strong tendency for the reversing exchangers to be superseded by this arrangement. Due to the ever increasing cost of energy, optimization studies are today pushed much further than they used to be; as a consequence there have been major changes in the size of equipment, improvements in the machinery, and simultaneous developments in instrumentation

  4. CALDER: High-sensitivity cryogenic light detectors

    International Nuclear Information System (INIS)

    Casali, N.; Bellini, F.; Cardani, L.

    2017-01-01

    The current bolometric experiments searching for rare processes such as neutrinoless double-beta decay or dark matter interaction demand for cryogenic light detectors with high sensitivity, large active area and excellent scalability and radio-purity in order to reduce their background budget. The CALDER project aims to develop such kind of light detectors implementing phonon-mediated Kinetic Inductance Detectors (KIDs). The goal for this project is the realization of a 5 × 5 cm"2 light detector working between 10 and 100mK with a baseline resolution RMS below 20 eV. In this work the characteristics and the performances of the prototype detectors developed in the first project phase will be shown.

  5. Rotary bayonets for cryogenic and vacuum service

    International Nuclear Information System (INIS)

    Rucinski, R.A.; Dixon, K.D.; Krasa, R.; Krempetz, K.J.; Mulholland, G.T.; Trotter, G.R.; Urbin, J.B.

    1993-07-01

    Rotary bayonets were designed, tested, and installed for liquid nitrogen, liquid argon, and vacuum service. This paper will present the design, testing, and service record for two sizes of vacuum jacketed cryogenic rotary bayonets and two sizes of vacuum service rotary bayonets. Materials used in construction provide electrical isolation across the bayonet joint. The joint permits 360 degrees of rotation between the male and female pipe sections while maintaining integrity of service. Assemblies using three such joints were built to allow end connection points to be translated through at least 1 meter of horizontal travel while kept in service. Vacuum jacketed sizes built in-house at Fermi National Accelerator Laboratory are 1-1/2 in. inner pipe size, 3 in. vacuum jacket, and 4 in. inner pipe size, 6 in. vacuum jacket The single wall vacuum service bayonets are in 4 in. and 6 in. pipe sizes. The bayonets have successfully been in active service for over one year

  6. Cryogenically enhanced magneto-Archimedes levitation

    Energy Technology Data Exchange (ETDEWEB)

    Catherall, A T; Lopez-Alcaraz, P; Benedict, K A; King, P J; Eaves, L [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

    2005-05-01

    The application of both a strong magnetic field and magnetic field gradient to a diamagnetic body can produce a vertical force which is sufficient to counteract its weight due to gravity. By immersing the body in a paramagnetic fluid, an additional adjustable magneto-buoyancy force is generated which enhances the levitation effect. Here we show that cryogenic oxygen and oxygen-nitrogen mixtures in both gaseous and liquid form provide sufficient buoyancy to permit the levitation and flotation of a wide range of materials. These fluids may provide an alternative to synthetic ferrofluids for the separation of minerals. We also report the dynamics of corrugation instabilities on the surface of magnetized liquid oxygen.

  7. Cryogenically enhanced magneto-Archimedes levitation

    International Nuclear Information System (INIS)

    Catherall, A T; Lopez-Alcaraz, P; Benedict, K A; King, P J; Eaves, L

    2005-01-01

    The application of both a strong magnetic field and magnetic field gradient to a diamagnetic body can produce a vertical force which is sufficient to counteract its weight due to gravity. By immersing the body in a paramagnetic fluid, an additional adjustable magneto-buoyancy force is generated which enhances the levitation effect. Here we show that cryogenic oxygen and oxygen-nitrogen mixtures in both gaseous and liquid form provide sufficient buoyancy to permit the levitation and flotation of a wide range of materials. These fluids may provide an alternative to synthetic ferrofluids for the separation of minerals. We also report the dynamics of corrugation instabilities on the surface of magnetized liquid oxygen

  8. Cryogenically assisted abrasive jet micromachining of polymers

    International Nuclear Information System (INIS)

    Getu, H; Papini, M; Spelt, J K

    2008-01-01

    The abrasive jet micromachining (AJM) of elastomers and polymers such as polydimethylsiloxane (PDMS), acrylonitrile butadiene styrene (ABS) and polytetrafluoroethylene (PTFE) for use in micro-fluidic devices was found to be very slow or impossible at room temperature. To enhance the material removal rate in such materials, a stream of liquid nitrogen (LN 2 ) was injected into the abrasive jet, cooling the target to cryogenic temperatures. Erosion rate measurements on the three polymeric materials (PDMS, ABS and PTFE) with and without the use of LN 2 were compared along with the profiles of micromachined channels and holes. It was found that the use of LN 2 cooling caused brittle erosion in PDMS, allowing it to be micromachined successfully. An erosion rate increase was also observed in PTFE and ABS at high and intermediate impact angles. The use of LN 2 also was found to reduce particle embedding

  9. Helium Inventory Management For LHC Cryogenics

    CERN Document Server

    Pyarali, Maisam

    2017-01-01

    The LHC is a 26.7 km circumference ring lined with superconducting magnets that operate at 1.9 K. These magnets are used to control the trajectory of beams of protons traveling in opposite directions and collide them at various experimental sites across the LHC where their debris is analyzed. The focus of this paper is the cryogenic system that allows the magnets to operate in their superconducting states. It aims to highlight the operating principles of helium refrigeration and liquefaction, with and without nitrogen pre-cooling; discuss the various refrigerators and liquefiers used at CERN for both LHC and Non-LHC applications, with their liquefaction capacities and purposes; and finally to deliberate the management of the LHC inventory and how it contributes to the strategic decision CERN makes regarding the inventory management during the Year-End Technical Stop (YETS), Extended Year-End Technical Stop (EYETS) and long shutdowns.

  10. Hermeticity of three cryogenic calorimeter geometries

    International Nuclear Information System (INIS)

    Strovink, M.; Wormersley, W.J.; Forden, G.E.

    1989-04-01

    We calculate the effect of cracks and dead material on resolution in three simplified cryogenic calorimeter geometries, using a crude approximation that neglects transverse shower spreading and considers only a small set of incident angles. For each dead region, we estimate the average unseen energy using a shower parametrization, and relate it to resolution broadening using a simple approximation that agrees with experimental data. Making reasonable and consistent assumptions on cryostat wall thicknesses, we find that the effects of cracks and dead material dominate the expected resolution in the region where separate ''barrel'' and ''end'' cryostats meet. This is particularly true for one geometry in which the end calorimeter caps the barrel and also protrudes into the hole within it. We also find that carefully designed auxiliary ''crack filler'' detectors can substantially reduce the loss of resolution in these areas. 6 figs

  11. Stainless steels for cryogenic bolts and nuts

    International Nuclear Information System (INIS)

    Leroy, F.; Rabbe, P.; Odin, G.

    1975-01-01

    Stainless steel for cryogenic applications are generally austenitic steels which, under the effect of cold-drawing, can or cannot undergo a partial martensitic transformation according to their composition. It has been shown that very high ductility and endurance characteristics at low temperatures, together with very high yield strength and resistances values, can be attained with grades of nitrogenous steels of types Z2CN18-10N and Z3CMN18-8-6N. Optimum ductility values are obtained by employing to the best possible, the martensitic transformations which develop during cold-drawing. From the plotting of the rational traction curves, it is possible to analyse very simply the influence of the composition on the martensitic transformations [fr

  12. First Experience with the LHC Cryogenic Instrumentation

    CERN Document Server

    Vauthier, N; Balle, Ch; Casas-Cubillos, J; Ciechanowski, M; Fernandez-Penacoba, G; Fortescue-Beck, E; Gomes, P; Jeanmonod, N; Lopez-Lorente, A; Suraci, A

    2008-01-01

    The LHC under commissioning at CERN will be the world's largest superconducting accelerator and therefore makes extensive use of cryogenic instruments. These instruments are installed in the tunnel and therefore have to withstand the LHC environment that imposes radiation-tolerant design and construction. Most of the instruments require individual calibration; some of them exhibit several variants as concerns measuring span; all relevant data are therefore stored in an Oracle® database. Those data are used for the various quality assurance procedures defined for installation and commissioning, as well as for generating tables used by the control system to configure automatically the input/output channels. This paper describes the commissioning of the sensors and the corresponding electronics, the first measurement results during the cool-down of one machine sector; it discusses the different encountered problems and their corresponding solutions.

  13. Cryogenic Wind Tunnel Models. Design and Fabrication

    Science.gov (United States)

    Young, C. P., Jr. (Compiler); Gloss, B. B. (Compiler)

    1983-01-01

    The principal motivating factor was the National Transonic Facility (NTF). Since the NTF can achieve significantly higher Reynolds numbers at transonic speeds than other wind tunnels in the world, and will therefore occupy a unique position among ground test facilities, every effort is being made to ensure that model design and fabrication technology exists to allow researchers to take advantage of this high Reynolds number capability. Since a great deal of experience in designing and fabricating cryogenic wind tunnel models does not exist, and since the experience that does exist is scattered over a number of organizations, there is a need to bring existing experience in these areas together and share it among all interested parties. Representatives from government, the airframe industry, and universities are included.

  14. Rotary bayonets for cryogenic and vacuum service

    International Nuclear Information System (INIS)

    Rucinski, R.A.; Dixon, K.D.; Krasa, R.; Krempetz, K.J.; Mulholland, G.T.; Trotter, G.R.; Urbin, J.B.

    1994-01-01

    Rotary bayonets were designed, tested, and installed for liquid nitrogen, liquid argon, and vacuum service. This paper will present the design, testing, and service record for two sizes of vacuum jacketed cryogenic rotary bayonets and two sizes of vacuum service rotary bayonets. Materials used in construction provide electrical isolation across the bayonet joint. The joint permits 360 degrees of rotation between the male and female pipe sections while maintaining integrity of service. Assemblies using three such joints were built to allow end connection points to be translated through at least 1 meter of horizontal travel while kept in service. Vacuum jacketed sizes built in-house at Fermi National Accelerator Laboratory are 1 1/2 inches inner pipe size, 3 inches vacuum jacket, and 4 inches inner pipe size, 6 inches vacuum jacket. The single wall vacuum service bayonets are in 4 inch and 6 inch pipe sizes. The bayonets have successfully been in active service for over one year

  15. Initial performance of upgraded Tevatron cryogenic systems

    International Nuclear Information System (INIS)

    Norris, B.L.

    1996-09-01

    Fermilab began operating a re-designed satellite refrigerator systems in November 1993. Upgrades were installed to operate the Tevatron at a magnet temperature of 3.5 K, approximately 1K lower than the original design. Refrigerator upgrades included new valve boxes, larger reciprocating expanders, the installation of cold vapor compressors, new sub-atmospheric instrumentation and an entirely new distributed controls system. Cryogenic system reliability data for Colliding Physics Run 1B is presented emphasizing a failure analysis for each aspect of the upgrade. Comparison to data for Colliding Physics Run 1A (previous to upgrade) is presented to show the impact of a major system overhaul. New operational problems and their solutions are presented in detail

  16. Nuclear Cryogenic Propulsion Stage Affordable Development Strategy

    Science.gov (United States)

    Doughty, Glen E.; Gerrish, H. P.; Kenny, R. J.

    2014-01-01

    The development of nuclear power for space use in nuclear thermal propulsion (NTP) systems will involve significant expenditures of funds and require major technology development efforts. The development effort must be economically viable yet sufficient to validate the systems designed. Efforts are underway within the National Aeronautics and Space Administration's (NASA) Nuclear Cryogenic Propulsion Stage Project (NCPS) to study what a viable program would entail. The study will produce an integrated schedule, cost estimate and technology development plan. This will include the evaluation of various options for test facilities, types of testing and use of the engine, components, and technology developed. A "Human Rating" approach will also be developed and factored into the schedule, budget and technology development approach.

  17. Practical analog electronics for technicians

    CERN Document Server

    Kimber, W A

    2013-01-01

    'Practical Analog Electronics for Technicians' not only provides an accessible introduction to electronics, but also supplies all the problems and practical activities needed to gain hands-on knowledge and experience. This emphasis on practice is surprisingly unusual in electronics texts, and has already gained Will Kimber popularity through the companion volume, 'Practical Digital Electronics for Technicians'. Written to cover the Advanced GNVQ optional unit in electronics, this book is also ideal for BTEC National, A-level electronics and City & Guilds courses. Together with 'Practical Digit

  18. Resistive RAMs as analog trimming elements

    Science.gov (United States)

    Aziza, H.; Perez, A.; Portal, J. M.

    2018-04-01

    This work investigates the use of Resistive Random Access Memory (RRAM) as an analog trimming device. The analog storage feature of the RRAM cell is evaluated and the ability of the RRAM to hold several resistance states is exploited to propose analog trim elements. To modulate the memory cell resistance, a series of short programming pulses are applied across the RRAM cell allowing a fine calibration of the RRAM resistance. The RRAM non volatility feature makes the analog device powers up already calibrated for the system in which the analog trimmed structure is embedded. To validate the concept, a test structure consisting of a voltage reference is evaluated.

  19. Analog and mixed-signal electronics

    CERN Document Server

    Stephan, Karl

    2015-01-01

    A practical guide to analog and mixed-signal electronics, with an emphasis on design problems and applications This book provides an in-depth coverage of essential analog and mixed-signal topics such as power amplifiers, active filters, noise and dynamic range, analog-to-digital and digital-to-analog conversion techniques, phase-locked loops, and switching power supplies. Readers will learn the basics of linear systems, types of nonlinearities and their effects, op-amp circuits, the high-gain analog filter-amplifier, and signal generation. The author uses system design examples to motivate

  20. Analog circuit design art, science, and personalities

    CERN Document Server

    Williams, Jim

    1991-01-01

    Analog Circuit Design: Art, Science, and Personalities discusses the many approaches and styles in the practice of analog circuit design. The book is written in an informal yet informative manner, making it easily understandable to those new in the field. The selection covers the definition, history, current practice, and future direction of analog design; the practice proper; and the styles in analog circuit design. The book also includes the problems usually encountered in analog circuit design; approach to feedback loop design; and other different techniques and applications. The text is