Conceptual design of the cryostat for the new high luminosity (HL-LHC) triplet magnets

NASA Astrophysics Data System (ADS)

Ramos, D.; Parma, V.; Moretti, M.; Eymin, C.; Todesco, E.; Van Weelderen, R.; Prin, H.; Berkowitz Zamora, D.

2017-12-01

The High Luminosity LHC (HL-LHC) is a project to upgrade the LHC collider after 2020-2025 to increase the integrated luminosity by about one order of magnitude and extend the physics production until 2035. An upgrade of the focusing triplets insertion system for the ATLAS and CMS experiments is foreseen using superconducting magnets operating in a pressurised superfluid helium bath at 1.9 K. This will require the design and construction of four continuous cryostats, each about sixty meters in length and one meter in diameter, for the final beam focusing quadrupoles, corrector magnets and beam separation dipoles. The design is constrained by the dimensions of the existing tunnel and accessibility restrictions imposing the integration of cryogenic piping inside the cryostat, thus resulting in a very compact integration. As the alignment and position stability of the magnets is crucial for the luminosity performance of the machine, the magnet support system must be carefully designed in order to cope with parasitic forces and thermo-mechanical load cycles. In this paper, we present the conceptual design of the cryostat and discuss the approach to address the stringent and often conflicting requirements of alignment, integration and thermal aspects.

A sigh of relief or a sigh of expected relief: Sigh rate in response to dyspnea relief.

PubMed

Vlemincx, Elke; Meulders, Michel; Luminet, Olivier

2018-02-01

Research has suggested that sighs may serve a regulatory function during stress and emotions by facilitating relief. Evidence supports the hypotheses that sighs both express and induce relief from stress. To explore the potential role of sighs in the regulation of symptoms, the present study aimed to investigate the relationship between sighs and relief of symptoms, and relief of dyspnea, specifically. Healthy volunteers participated in two studies (N = 44, N = 47) in which dyspnea was induced by mild (10 cmH 2 O/l/s) or high (20 cmH 2 0/l/s) inspiratory resistances. Dyspnea relief was induced by the offset of the inspiratory resistances (transitions from high and mild inspiratory resistance to no resistance). Control comparisons included dyspnea increases (transitions from no or mild inspiratory resistance to high inspiratory resistance) and dyspnea continuations (continuations of either no resistance or a high resistance). In Experiment 1, dyspnea levels were cued. In Experiment 2, no cues were provided. Sigh rate during dyspnea relief was significantly higher compared to control conditions, and sigh rate increased as self-reported dyspnea decreased. Additionally, sigh rate was higher during cued dyspnea relief compared to noncued dyspnea relief. These results suggest that sighs are important markers of dyspnea relief. Moreover, sighs may importantly express dyspnea relief, as they are related to experiential dyspnea decreases and occur more frequently during expected dyspnea relief. These findings suggest that sighs may not only be important in the regulation of stress and emotions, but also may be functional in the regulation of dyspnea. © 2017 Society for Psychophysiological Research.

Radiation Resistance and Life Time Estimates at Cryogenic Temperatures of Series Produced By-Pass Diodes for the LHC Magnet Protection

NASA Astrophysics Data System (ADS)

Denz, R.; Gharib, A.; Hagedorn, D.

2004-06-01

For the protection of the LHC superconducting magnets about 2100 specially developed by-pass diodes have been manufactured in industry and more than one thousand of these diodes have been mounted into stacks and tested in liquid helium. By-pass diode samples, taken from the series production, have been submitted to irradiation tests at cryogenic temperatures together with some prototype diodes up to an accumulated dose of about 2 kGy and neutron fluences up to about 3.0 1013 n cm-2 with and without intermediate warm up to 300 K. The device characteristics of the diodes under forward bias and reverse bias have been measured at 77 K and ambient versus dose and the results are presented. Using a thermo-electrical model and new estimates for the expected dose in the LHC, the expected lifetime of the by-pass diodes has been estimated for various positions in the LHC arcs. It turns out that for all of the by-pass diodes across the arc elements the radiation resistance is largely sufficient. In the dispersion suppresser regions of the LHC, on a few diodes annual annealing during the shut down of the LHC must be applied or those diodes may need to be replaced after some time.

CALCULATED REGENERATOR PERFORMANCE AT 4 K WITH HELIUM-4 AND HELIUM-3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radebaugh, Ray; Huang Yonghua; O'Gallagher, Agnes

2008-03-16

The helium-4 working fluid in regenerative cryocoolers operating with the cold end near 4 K deviates considerably from an ideal gas. As a result, losses in the regenerator, given by the time-averaged enthalpy flux, are increased and are strong functions of the operating pressure and temperature. Helium-3, with its lower boiling point, behaves somewhat closer to an ideal gas in this low temperature range and can reduce the losses in 4 K regenerators. An analytical model is used to find the fluid properties that strongly influence the regenerator losses as well as the gross refrigeration power. The thermodynamic and transportmore » properties of helium-3 were incorporated into the latest NIST regenerator numerical model, known as REGEN3.3, which was used to model regenerator performance with either helium-4 or helium-3. With this model we show how the use of helium-3 in place of helium-4 can improve the performance of 4 K regenerative cryocoolers. The effects of operating pressure, warm-end temperature, and frequency on regenerators with helium-4 and helium-3 are investigated and compared. The results are used to find optimum operating conditions. The frequency range investigated varies from 1 Hz to 30 Hz, with particular emphasis on higher frequencies.« less

Quench simulations for superconducting elements in the LHC accelerator

NASA Astrophysics Data System (ADS)

Sonnemann, F.; Schmidt, R.

2000-08-01

The design of the protection system for the superconducting elements in an accelerator such as the large Hadron collider (LHC), now under construction at CERN, requires a detailed understanding of the thermo-hydraulic and electrodynamic processes during a quench. A numerical program (SPQR - simulation program for quench research) has been developed to evaluate temperature and voltage distributions during a quench as a function of space and time. The quench process is simulated by approximating the heat balance equation with the finite difference method in presence of variable cooling and powering conditions. The simulation predicts quench propagation along a superconducting cable, forced quenching with heaters, impact of eddy currents induced by a magnetic field change, and heat transfer through an insulation layer into helium, an adjacent conductor or other material. The simulation studies allowed a better understanding of experimental quench data and were used for determining the adequate dimensioning and protection of the highly stabilised superconducting cables for connecting magnets (busbars), optimising the quench heater strip layout for the main magnets, and studying quench back by induced eddy currents in the superconductor. After the introduction of the theoretical approach, some applications of the simulation model for the LHC dipole and corrector magnets are presented and the outcome of the studies is compared with experimental data.

HL-LHC and HE-LHC Upgrade Plans and Opportunities for US Participation

NASA Astrophysics Data System (ADS)

Apollinari, Giorgio

2017-01-01

The US HEP community has identified the exploitation of physics opportunities at the High Luminosity-LHC (HL-LHC) as the highest near-term priority. Thanks to multi-year R&D programs, US National Laboratories and Universities have taken the leadership in the development of technical solutions to increase the LHC luminosity, enabling the HL-LHC Project and uniquely positioning this country to make critical contributions to the LHC luminosity upgrade. This talk will describe the shaping of the US Program to contribute in the next decade to HL-LHC through newly developed technologies such as Nb3Sn focusing magnets or superconducting crab cavities. The experience gained through the execution of the HL-LHC Project in the US will constitute a pool of knowledge and capabilities allowing further developments in the future. Opportunities for US participations in proposed hadron colliders, such as a possible High Energy-LHC (HE-LHC), will be described as well.

5-year operation experience with the 1.8 K refrigeration units of the LHC cryogenic system

NASA Astrophysics Data System (ADS)

Ferlin, G.; Tavian, L.; Claudet, S.; Pezzetti, M.

2015-12-01

Since 2009, the Large Hadron Collider (LHC) is in operation at CERN. The LHC superconducting magnets distributed over eight sectors of 3.3-km long are cooled at 1.9 K in pressurized superfluid helium. The nominal operating temperature of 1.9 K is produced by eight 1.8-K refrigeration units based on centrifugal cold compressors (3 or 4 stages depending to the vendor) combined with warm volumetric screw compressors with sub-atmospheric suction. After about 5 years of continuous operation, we will present the results concerning the availability for the final user of these refrigeration units and the impact of the design choice on the recovery time after a system trip. We will also present the individual results for each rotating machinery in terms of failure origin and of Mean Time between Failure (MTBF), as well as the consolidations and upgrades applied to these refrigeration units.

Helium-Recycling Plant

NASA Technical Reports Server (NTRS)

Cook, Joseph

1996-01-01

Proposed system recovers and stores helium gas for reuse. Maintains helium at 99.99-percent purity, preventing water vapor from atmosphere or lubricating oil from pumps from contaminating gas. System takes in gas at nearly constant low back pressure near atmospheric pressure; introduces little or no back pressure into source of helium. Concept also extended to recycling of other gases.

Cryogenic Testing of High Current By-Pass Diode Stacks for the Protection of the Superconducting Magnets in the LHC

NASA Astrophysics Data System (ADS)

Gharib, A.; Hagedorn, D.; Della Corte, A.; Fiamozzi Zignani, C.; Turtu, S.; Brown, D.; Rout, C.

2004-06-01

For the protection of the LHC superconducting magnets, about 2100 specially developed by-pass diodes were manufactured by DYNEX SEMICONDUCTOR LTD (Lincoln, GB) and about 1300 of these diodes were mounted into diode stacks and submitted to tests at cryogenic temperatures. To date about 800 dipole diode stacks and about 250 quadrupole diode stacks for the protection of the superconducting lattice dipole and lattice quadrupole magnets have been assembled at OCEM (Bologna,Italy) and successfully tested in liquid helium at ENEA (Frascati, Italy). This report gives an overview of the test results obtained so far. After a short description of the test installations and test procedures, a statistical analysis is presented for test data during diode production as well as for the performance of the diode stacks during testing in liquid helium, including failure rates and degradation of the diodes.

Does one need a 4.5 K screen in cryostats of superconducting accelerator devices operating in superfluid helium? lessons from the LHL

NASA Astrophysics Data System (ADS)

Lebrun, Philippe; Parma, Vittorio; Tavian, Laurent

2014-01-01

Superfluid helium is increasingly used as a coolant for superconducting devices in particle accelerators: the lower temperature enhances the performance of superconductors in high-field magnets and reduces BCS losses in RF acceleration cavities, while the excellent transport properties of superfluid helium can be put to work in efficient distributed cooling systems. The thermodynamic penalty of operating at lower temperature however requires careful management of the heat loads, achieved inter alia through proper design and construction of the cryostats. A recurrent question appears to be that of the need and practical feasibility of an additional screen cooled by normal helium at around 4.5 K surrounding the cold mass at about 2 K, in such cryostats equipped with a standard 80 K screen. We introduce the issue in terms of first principles applied to the configuration of the cryostats, discuss technical constraints and economical limitations, and illustrate the argumentation with examples taken from large projects confronted with this issue, i.e. CEBAF, SPL, ESS, LHC, TESLA, European X-FEL, ILC.

PDF4LHC recommendations for LHC Run II

DOE PAGES

Butterworth, Jon; Carrazza, Stefano; Cooper-Sarkar, Amanda; ...

2016-01-06

We provide an updated recommendation for the usage of sets of parton distribution functions (PDFs) and the assessment of PDF and PDF+αs uncertainties suitable for applications at the LHC Run II. We review developments since the previous PDF4LHC recommendation, and discuss and compare the new generation of PDFs, which include substantial information from experimental data from the Run I of the LHC. We then propose a new prescription for the combination of a suitable subset of the available PDF sets, which is presented in terms of a single combined PDF set. Lastly, we finally discuss tools which allow for themore » delivery of this combined set in terms of optimized sets of Hessian eigenvectors or Monte Carlo replicas, and their usage, and provide some examples of their application to LHC phenomenology.« less

Iraq’s Debt Relief: Procedure and Potential Implications for International Debt Relief

DTIC Science & Technology

2008-10-02

Order Code RL33376 Iraq’s Debt Relief: Procedure and Potential Implications for International Debt Relief Updated October 2, 2008 Martin A. Weiss...4. TITLE AND SUBTITLE Iraq?s Debt Relief: Procedure and Potential Implications for International Debt Relief 5a. CONTRACT NUMBER 5b. GRANT NUMBER...b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Iraq’s Debt Relief: Procedure

Alternative medicine - pain relief

MedlinePlus

Acupuncture - pain relief; Hypnosis - pain relief; Guided imagery - pain relief ... forms of alternative medicine. Alternatives to medicines include acupuncture, chiropractic, massage, hypnosis, biofeedback, meditation, yoga, and tai- ...

Precision searches in dijets at the HL-LHC and HE-LHC

NASA Astrophysics Data System (ADS)

Chekanov, S. V.; Childers, J. T.; Proudfoot, J.; Wang, R.; Frizzell, D.

2018-05-01

This paper explores the physics reach of the High-Luminosity Large Hadron Collider (HL-LHC) for searches of new particles decaying to two jets. We discuss inclusive searches in dijets and b-jets, as well as searches in semi-inclusive events by requiring an additional lepton that increases sensitivity to different aspects of the underlying processes. We discuss the expected exclusion limits for generic models predicting new massive particles that result in resonant structures in the dijet mass. Prospects of the Higher-Energy LHC (HE-LHC) collider are also discussed. The study is based on the Pythia8 Monte Carlo generator using representative event statistics for the HL-LHC and HE-LHC running conditions. The event samples were created using supercomputers at NERSC.

A portable helium sniffer

USGS Publications Warehouse

Friedman, Irving; Denton, E.H.

1976-01-01

A portable helium sniffer has been developed for field use. The instrument is mounted in a four-wheel-drive pickup truck and can detect 50 parts per billion of helium in soil gas. The usefulness of helium sniffing in soil is being investigated as a prospecting tool in gas, oil, uranium, and geothermal prospecting as well as in earthquake prediction.

Helium in inert matrix dispersion fuels

NASA Astrophysics Data System (ADS)

van Veen, A.; Konings, R. J. M.; Fedorov, A. V.

2003-07-01

The behaviour of helium, an important decay product in the transmutation chains of actinides, in dispersion-type inert matrix fuels is discussed. A phenomenological description of its accumulation and release in CERCER and CERMET fuel is given. A summary of recent He-implantation studies with inert matrix metal oxides (ZrO 2, MgAl 2O 4, MgO and Al 2O 3) is presented. A general picture is that for high helium concentrations helium and vacancy defects form helium clusters which convert into over-pressurized bubbles. At elevated temperature helium is released from the bubbles. On some occasions thermal stable nano-cavities or nano-pores remain. On the basis of these results the consequences for helium induced swelling and helium storage in oxide matrices kept at 800-1000 °C will be discussed. In addition, results of He-implantation studies for metal matrices (W, Mo, Nb and V alloys) will be presented. Introduction of helium in metals at elevated temperatures leads to clustering of helium to bubbles. When operational temperatures are higher than 0.5 melting temperature, swelling and helium embrittlement might occur.

Cavitation in flowing superfluid helium

NASA Technical Reports Server (NTRS)

Daney, D. E.

1988-01-01

Flowing superfluid helium cavitates much more readily than normal liquid helium, and there is a marked difference in the cavitation behavior of the two fluids as the lambda point is traversed. Examples of cavitation in a turbine meter and centrifugal pump are given, together with measurements of the cavitation strength of flowing superfluid helium. The unusual cavitation behavior of superfluid helium is attributed to its immense thermal conductivity .

Simplified Methodology to Estimate the Maximum Liquid Helium (LHe) Cryostat Pressure from a Vacuum Jacket Failure

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.; Richards, W. Lance

2015-01-01

The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared astronomical observation experiments. These experiments carry sensors cooled to liquid helium temperatures. The liquid helium supply is contained in large (i.e., 10 liters or more) vacuum-insulated dewars. Should the dewar vacuum insulation fail, the inrushing air will condense and freeze on the dewar wall, resulting in a large heat flux on the dewar's contents. The heat flux results in a rise in pressure and the actuation of the dewar pressure relief system. A previous NASA Engineering and Safety Center (NESC) assessment provided recommendations for the wall heat flux that would be expected from a loss of vacuum and detailed an appropriate method to use in calculating the maximum pressure that would occur in a loss of vacuum event. This method involved building a detailed supercritical helium compressible flow thermal/fluid model of the vent stack and exercising the model over the appropriate range of parameters. The experimenters designing science instruments for SOFIA are not experts in compressible supercritical flows and do not generally have access to the thermal/fluid modeling packages that are required to build detailed models of the vent stacks. Therefore, the SOFIA Program engaged the NESC to develop a simplified methodology to estimate the maximum pressure in a liquid helium dewar after the loss of vacuum insulation. The method would allow the university-based science instrument development teams to conservatively determine the cryostat's vent neck sizing during preliminary design of new SOFIA Science Instruments. This report details the development of the simplified method, the method itself, and the limits of its applicability. The simplified methodology provides an estimate of the dewar pressure after a loss of vacuum insulation that can be used for the initial design of the liquid helium dewar vent stacks. However, since it is not an exact

Thermo-electric analysis of the interconnection of the LHC main superconducting bus bars

NASA Astrophysics Data System (ADS)

Granieri, P. P.; Breschi, M.; Casali, M.; Bottura, L.; Siemko, A.

2013-01-01

Spurred by the question of the maximum allowable energy for the operation of the Large Hadron Collider (LHC), we have progressed in the understanding of the thermo-electric behavior of the 13 kA superconducting bus bars interconnecting its main magnets. A deep insight of the underlying mechanisms is required to ensure the protection of the accelerator against undesired effects of resistive transitions. This is especially important in case of defective interconnections which can jeopardize the operation of the whole LHC. In this paper we present a numerical model of the interconnections between the main dipole and quadrupole magnets, validated against experimental tests of an interconnection sample with a purposely built-in defect. We consider defective interconnections featuring a lack of bonding among the superconducting cables and the copper stabilizer components, such as those that could be present in the machine. We evaluate the critical defect length limiting the maximum allowable current for powering the magnets. We determine the dependence of the critical defect length on different parameters as the heat transfer towards the cooling helium bath, the quality of manufacturing, the operating conditions and the protection system parameters, and discuss the relevant mechanisms.

Development of a transferline connecting a helium liquefier coldbox and a liquid helium Dewar

NASA Astrophysics Data System (ADS)

Menon, Rajendran S.; Rane, Tejas; Chakravarty, Anindya; Joemon, V.

2017-02-01

A helium liquefier with demonstrated capacity of 32 1/hr has been developed by BARC. Mumbai. A transferline for two way flow of helium between the helium liquefier coldbox and receiver Dewar has been developed in-house at BARC. Further, a functionally similar, but structurally improved transferline has been developed through a local fabricator. This paper describes and discusses issues related to the development of these cryogenic transferlines. The developed transferlines have been tested with a flow of liquid nitrogen and successfully utilised later in the helium liquefier plant.

Effects of helium concentration and radiation temperature on interaction of helium atoms with displacement cascades in bcc iron

NASA Astrophysics Data System (ADS)

Gao, Chan; Tian, Dongfeng; Li, Maosheng; Qian, Dazhi

2018-03-01

In fusion applications, helium, implanted or created by transmutation, plays an important role in the response of reduced-activation ferritic/martensitic steels to neutron radiation damage. The effects of helium concentration and radiation temperature on interaction of interstitial helium atoms with displacement cascades have been studied in Fe-He system using molecular dynamics with recently developed Fe-He potential. Results indicate that interstitial helium atoms produce no additional defects at peak time and promote recombination of Frenkel pairs at lower helium concentrations, but suppress recombination of Frenkel pairs at larger helium concentrations. Moreover, large helium concentrations promote the production of defects at the end of cascades. The number of substitutional helium atoms increases with helium concentration at peak time and the end of cascades, but the number of substitutional helium atoms at peak time is smaller than that at the end of displacement cascades. High radiation temperatures promote the production at peak time and the recombination of defects at the end of cascades. The number of substitutional helium atoms increases with radiation temperature, but that at peak time is smaller than that at the end of cascades.

An Assessment of Helium Evolution from Helium-Saturated Propellant Depressurization in Space

NASA Technical Reports Server (NTRS)

Nguyen, Bich N.; Best, Frederick; Wong, Tony; Kurwitz, Cable; McConnaughey, H. (Technical Monitor)

2001-01-01

Helium evolution from the transfer of helium-saturated propellant in space is quantified to assess its impacts from creating two-phase gas/liquid flow from the supply tank, gas injection into the receiving tank, and liquid discharge from the receiving tank. Propellant transfer takes place between two similar tanks whose maximum storage capacity is approximately 2.55 cubic meters each. The maximum on-orbit propellants transfer capability is 9000 lbm (fuel and oxidizer). The transfer line is approximately 1.27 cm in diameter and 6096 cm in length and comprised of the fluid interconnect system (FICS), the orbiter propellant transfer system (OPTS), and the International Space Station (ISS) propulsion module (ISSPM). The propellant transfer rate begins at approximately 11 liter per minute (lpm) and subsequently drops to approximately 0.5 lpm. The tank nominal operating pressure is approximately 1827 kPa (absolute). The line pressure drops for Monomethy1hydrazine (MMH) and Nitrogen tetroxide (NTO) at 11.3 lpm are approximately 202 kPa and 302 kPa, respectively. The pressure-drop results are based on a single-phase flow. The receiving tank is required to vent from approximately 1827 kPa to a lower pressure to affect propellant transfer. These pressure-drop scenarios cause the helium-saturated propellants to release excess helium. For tank ullage venting, the maximum volumes of helium evolved at tank pressure are approximately 0.5 ft3 for MMH and 2 ft3 for NTO. In microgravity environment, due to lack of body force, the helium evolution from a liquid body acts to propel it, which influences its fluid dynamics. For propellant transfer, the volume fractions of helium evolved at line pressure are 0.1% by volume for MMH and 0.6 % by volume for NTO at 11.3 lpm. The void fraction of helium evolved varies as an approximate second order power function of flow rate.

Induced activation studies for the LHC upgrade to High Luminosity LHC

NASA Astrophysics Data System (ADS)

Adorisio, C.; Roesler, S.

2018-06-01

The Large Hadron Collider (LHC) will be upgraded in 2019/2020 to increase its luminosity (rate of collisions) by a factor of five beyond its design value and the integrated luminosity by a factor ten, in order to maintain scientific progress and exploit its full capacity. The novel machine configuration, called High Luminosity LHC (HL-LHC), will increase consequently the level of activation of its components. The evaluation of the radiological impact of the HL-LHC operation in the Long Straight Sections of the Insertion Region 1 (ATLAS) and Insertion Region 5 (CMS) is presented. Using the Monte Carlo code FLUKA, ambient dose equivalent rate estimations have been performed on the basis of two announced operating scenarios and using the latest available machine layout. The HL-LHC project requires new technical infrastructure with caverns and 300 m long tunnels along the Insertion Regions 1 and 5. The new underground service galleries will be accessible during the operation of the accelerator machine. The radiological risk assessment for the Civil Engineering work foreseen to start excavating the new galleries in the next LHC Long Shutdown and the radiological impact of the machine operation will be discussed.

Helium cluster isolation spectroscopy

NASA Astrophysics Data System (ADS)

Higgins, John Paul

Clusters of helium, each containing ~103- 104 atoms, are produced in a molecular beam and are doped with alkali metal atoms (Li, Na, and K) and large organic molecules. Electronic spectroscopy in the visible and UV regions of the spectrum is carried out on the dopant species. Since large helium clusters are liquid and attain an equilibrium internal temperature of 0.4 K, they interact weakly with atoms or molecules absorbed on their surface or resident inside the cluster. The spectra that are obtained are characterized by small frequency shifts from the positions of the gas phase transitions, narrow lines, and cold vibrational temperatures. Alkali atoms aggregate on the helium cluster surface to form dimers and trimers. The spectra of singlet alkali dimers exhibit the presence of elementary excitations in the superfluid helium cluster matrix. It is found that preparation of the alkali molecules on the surface of helium clusters leads to the preferential formation of high-spin, van der Waals bound, triplet dimers and quartet trimers. Four bound-bound and two bound-free transitions are observed in the triplet manifold of the alkali dimers. The quartet trimers serve as an ideal system for the study of a simple unimolecular reaction in the cold helium cluster environment. Analysis of the lowest quartet state provides valuable insight into three-body forces in a van der Waals trimer. The wide range of atomic and molecular systems studied in this thesis constitutes a preliminary step in the development of helium cluster isolation spectroscopy, a hybrid technique combining the advantages of high resolution spectroscopy with the synthetic, low temperature environment of matrices.

30 CFR 256.11 - Helium.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the manner required by the United States to such plants or reduction works as the United States may provide. (c) The extraction of helium shall not cause a reduction in the value of the lessee's gas or any... necessary for the extraction of helium. The extraction of helium shall not cause substantial delays in the...

30 CFR 256.11 - Helium.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Delivery shall be made in the manner required by the United States to such plants or reduction works as the United States may provide. (c) The extraction of helium shall not cause a reduction in the value of the... and other equipment necessary for the extraction of helium. The extraction of helium shall not cause...

Characterization of relief printing

NASA Astrophysics Data System (ADS)

Liu, Xing; Chen, Lin; Ortiz-Segovia, Maria-Valezzka; Ferwerda, James; Allebach, Jan

2014-03-01

Relief printing technology developed by Océ allows the superposition of several layers of colorant on different types of media which creates a variation of the surface height defined by the input to the printer. Evaluating the reproduction accuracy of distinct surface characteristics is of great importance to the application of the relief printing system. Therefore, it is necessary to develop quality metrics to evaluate the relief process. In this paper, we focus on the third dimension of relief printing, i.e. height information. To achieve this goal, we define metrics and develop models that aim to evaluate relief prints in two aspects: overall fidelity and surface finish. To characterize the overall fidelity, three metrics are calculated: Modulation Transfer Function (MTF), difference and root-mean-squared error (RMSE) between the input height map and scanned height map, and print surface angle accuracy. For the surface finish property, we measure the surface roughness, generate surface normal maps and develop a light reflection model that serves as a simulation of the differences between ideal prints and real prints that may be perceived by human observers. Three sets of test targets are designed and printed by the Océ relief printer prototypes for the calculation of the above metrics: (i) twisted target, (ii) sinusoidal wave target, and (iii) ramp target. The results provide quantitative evaluations of the printing quality in the third dimension, and demonstrate that the height of relief prints is reproduced accurately with respect to the input design. The factors that affect the printing quality include: printing direction, frequency and amplitude of the input signal, shape of relief prints. Besides the above factors, there are two additional aspects that influence the viewing experience of relief prints: lighting condition and viewing angle.

3He NMR studies on helium-pyrrole, helium-indole, and helium-carbazole systems: a new tool for following chemistry of heterocyclic compounds.

PubMed

Radula-Janik, Klaudia; Kupka, Teobald

2015-02-01

The (3)He nuclear magnetic shieldings were calculated for free helium atom and He-pyrrole, He-indole, and He-carbazole complexes. Several levels of theory, including Hartree-Fock (HF), Second-order Møller-Plesset Perturbation Theory (MP2), and Density Functional Theory (DFT) (VSXC, M062X, APFD, BHandHLYP, and mPW1PW91), combined with polarization-consistent pcS-2 and aug-pcS-2 basis sets were employed. Gauge-including atomic orbital (GIAO) calculated (3)He nuclear magnetic shieldings reproduced accurately previously reported theoretical values for helium gas. (3)He nuclear magnetic shieldings and energy changes as result of single helium atom approaching to the five-membered ring of pyrrole, indole, and carbazole were tested. It was observed that (3)He NMR parameters of single helium atom, calculated at various levels of theory (HF, MP2, and DFT) are sensitive to the presence of heteroatomic rings. The helium atom was insensitive to the studied molecules at distances above 5 Å. Our results, obtained with BHandHLYP method, predicted fairly accurately the He-pyrrole plane separation of 3.15 Å (close to 3.24 Å, calculated by MP2) and yielded a sizable (3)He NMR chemical shift (about -1.5 ppm). The changes of calculated nucleus-independent chemical shifts (NICS) with the distance above the rings showed a very similar pattern to helium-3 NMR chemical shift. The ring currents above the five-membered rings were seen by helium magnetic probe to about 5 Å above the ring planes verified by the calculated NICS index. Copyright © 2014 John Wiley & Sons, Ltd.

Physics perspectives with AFTER@LHC (A Fixed Target ExpeRiment at LHC)

NASA Astrophysics Data System (ADS)

Massacrier, L.; Anselmino, M.; Arnaldi, R.; Brodsky, S. J.; Chambert, V.; Da Silva, C.; Didelez, J. P.; Echevarria, M. G.; Ferreiro, E. G.; Fleuret, F.; Gao, Y.; Genolini, B.; Hadjidakis, C.; Hřivnáčová, I.; Kikola, D.; Klein, A.; Kurepin, A.; Kusina, A.; Lansberg, J. P.; Lorcé, C.; Lyonnet, F.; Martinez, G.; Nass, A.; Pisano, C.; Robbe, P.; Schienbein, I.; Schlegel, M.; Scomparin, E.; Seixas, J.; Shao, H. S.; Signori, A.; Steffens, E.; Szymanowski, L.; Topilskaya, N.; Trzeciak, B.; Uggerhøj, U. I.; Uras, A.; Ulrich, R.; Wagner, J.; Yamanaka, N.; Yang, Z.

2018-02-01

AFTER@LHC is an ambitious fixed-target project in order to address open questions in the domain of proton and neutron spins, Quark Gluon Plasma and high-x physics, at the highest energy ever reached in the fixed-target mode. Indeed, thanks to the highly energetic 7 TeV proton and 2.76 A.TeV lead LHC beams, center-of-mass energies as large as = 115 GeV in pp/pA and = 72 GeV in AA can be reached, corresponding to an uncharted energy domain between SPS and RHIC. We report two main ways of performing fixed-target collisions at the LHC, both allowing for the usage of one of the existing LHC experiments. In these proceedings, after discussing the projected luminosities considered for one year of data taking at the LHC, we will present a selection of projections for light and heavy-flavour production.

Pressure Relief Devices

NASA Astrophysics Data System (ADS)

Manha, William D.

2010-09-01

Pressure relief devices are used in pressure systems and on pressure vessels to prevent catastrophic rupture or explosion from excessive pressure. Pressure systems and pressure vessels have manufacturers maximum rated operating pressures or maximum design pressures(MDP) for which there are relatively high safety factors and minimum risk of rupture or explosion. Pressure systems and pressure vessels that have a potential to exceed the MDP by being connected to another higher pressure source, a compressor, or heat to water(boiler) are required to have over-pressure protecting devices. Such devices can be relief valves and/or burst discs to safely relieve potentially excessive pressure and prevent unacceptable ruptures and explosions which result in fail-safe pressure systems and pressure vessels. Common aerospace relief valve and burst disc requirements and standards will be presented. This will include the NASA PSRP Interpretation Letter TA-88-074 Fault Tolerance of Systems Using Specially Certified Burst Disks that dictates burst disc requirements for payloads on Shuttle. Two recent undesirable manned space payloads pressure relief devices and practices will be discussed, as well as why these practices should not be continued. One example for discussion is the use of three burst discs that have been placed in series to comply with safety requirements of three controls to prevent a catastrophic hazard of the over-pressurization and rupture of pressure system and/or vessels. The cavities between the burst discs are evacuated and are the reference pressures for activating the two upstream burst discs. If the upstream burst disc leaks into the reference cavity, the reference pressure increases and it can increase the burst disc activating pressure and potentially result in the burst disc assembly being ineffective for over pressure protection. The three burst discs-in-series assembly was found acceptable because the burst discs are designed for minimum risk(DFMR) of

Helium release during shale deformation: Experimental validation

DOE PAGES

Bauer, Stephen J.; Gardner, W. Payton; Heath, Jason E.

2016-07-01

This paper describes initial experimental results of helium tracer release monitoring during deformation of shale. Naturally occurring radiogenic 4He is present in high concentration in most shales. During rock deformation, accumulated helium could be released as fractures are created and new transport pathways are created. We present the results of an experimental study in which confined reservoir shale samples, cored parallel and perpendicular to bedding, which were initially saturated with helium to simulate reservoir conditions, are subjected to triaxial compressive deformation. During the deformation experiment, differential stress, axial, and radial strains are systematically tracked. Release of helium is dynamically measuredmore » using a helium mass spectrometer leak detector. Helium released during deformation is observable at the laboratory scale and the release is tightly coupled to the shale deformation. These first measurements of dynamic helium release from rocks undergoing deformation show that helium provides information on the evolution of microstructure as a function of changes in stress and strain.« less

Critical Landau Velocity in Helium Nanodroplets

NASA Astrophysics Data System (ADS)

Brauer, Nils B.; Smolarek, Szymon; Loginov, Evgeniy; Mateo, David; Hernando, Alberto; Pi, Marti; Barranco, Manuel; Buma, Wybren J.; Drabbels, Marcel

2013-10-01

The best-known property of superfluid helium is the vanishing viscosity that objects experience while moving through the liquid with speeds below the so-called critical Landau velocity. This critical velocity is generally considered a macroscopic property as it is related to the collective excitations of the helium atoms in the liquid. In the present work we determine to what extent this concept can still be applied to nanometer-scale, finite size helium systems. To this end, atoms and molecules embedded in helium nanodroplets of various sizes are accelerated out of the droplets by means of optical excitation, and the speed distributions of the ejected particles are determined. The measurements reveal the existence of a critical velocity in these systems, even for nanodroplets consisting of only a thousand helium atoms. Accompanying theoretical simulations based on a time-dependent density functional description of the helium confirm and further elucidate this experimental finding.

Helium-induced hardening effect in polycrystalline tungsten

NASA Astrophysics Data System (ADS)

Kong, Fanhang; Qu, Miao; Yan, Sha; Zhang, Ailin; Peng, Shixiang; Xue, Jianming; Wang, Yugang

2017-09-01

In this paper, helium induced hardening effect of tungsten was investigated. 50 keV He2+ ions at fluences vary from 5 × 1015 cm-2 to 5 × 1017 cm-2 were implanted into polycrystalline tungsten at RT to create helium bubble-rich layers near the surface. The microstructure and mechanical properties of the irradiated specimens were studied by TEM and nano-indentor. Helium bubble rich layers are formed in near surface region, and the layers become thicker with the rise of fluences. Helium bubbles in the area of helium concentration peak are found to grow up, while the bubble density is almost unchanged. Obvious hardening effect is induced by helium implantation in tungsten. Micro hardness increases rapidly with the fluence firstly, and more slowly when the fluence is above 5 × 1016 cm-2. The hardening effect of tungsten can be attributed to helium bubbles, which is found to be in agreement with the Bacon-Orowan stress formula. The growing diameter is the major factor rather than helium bubbles density (voids distance) in the process of helium implantation at fluences below 5 × 1017 cm-2.

Low helium flux from the mantle inferred from simulations of oceanic helium isotope data

NASA Astrophysics Data System (ADS)

Bianchi, Daniele; Sarmiento, Jorge L.; Gnanadesikan, Anand; Key, Robert M.; Schlosser, Peter; Newton, Robert

2010-09-01

The high 3He/ 4He isotopic ratio of oceanic helium relative to the atmosphere has long been recognized as the signature of mantle 3He outgassing from the Earth's interior. The outgassing flux of helium is frequently used to normalize estimates of chemical fluxes of elements from the solid Earth, and provides a strong constraint to models of mantle degassing. Here we use a suite of ocean general circulation models and helium isotope data obtained by the World Ocean Circulation Experiment to constrain the flux of helium from the mantle to the oceans. Our results suggest that the currently accepted flux is overestimated by a factor of 2. We show that a flux of 527 ± 102 mol year - 1 is required for ocean general circulation models that produce distributions of ocean ventilation tracers such as radiocarbon and chlorofluorocarbons that match observations. This new estimate calls for a reevaluation of the degassing fluxes of elements that are currently tied to the helium fluxes, including noble gases and carbon dioxide.

21 CFR 868.1640 - Helium gas analyzer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Helium gas analyzer. 868.1640 Section 868.1640...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1640 Helium gas analyzer. (a) Identification. A helium gas analyzer is a device intended to measure the concentration of helium in a gas...

21 CFR 868.1640 - Helium gas analyzer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Helium gas analyzer. 868.1640 Section 868.1640...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1640 Helium gas analyzer. (a) Identification. A helium gas analyzer is a device intended to measure the concentration of helium in a gas...

Transient boiling in two-phase helium natural circulation loops

NASA Astrophysics Data System (ADS)

Furci, H.; Baudouy, B.; Four, A.; Meuris, C.

2014-01-01

Two-phase helium natural circulation loops are used for cooling large superconducting magnets, as CMS for LHC. During normal operation or in the case of incidents, transients are exerted on the cooling system. Here a cooling system of this type is studied experimentally. Sudden power changes are operated on a vertical-heated-section natural convection loop, simulating a fast increase of heat deposition on magnet cooling pipes. Mass flow rate, heated section wall temperature and pressure drop variations are measured as a function of time, to assess the time behavior concerning the boiling regime according to the values of power injected on the heated section. The boiling curves and critical heat flux (CHF) values have been obtained in steady state. Temperature evolution has been observed in order to explore the operating ranges where heat transfer is deteriorated. Premature film boiling has been observed during transients on the heated section in some power ranges, even at appreciably lower values than the CHF. A way of attenuating these undesired temperature excursions has been identified through the application of high enough initial heating power.

Design of a 0-50 mbar pressure measurement channel compatible with the LHC tunnel radiation environment

NASA Astrophysics Data System (ADS)

Casas, Juan; Jelen, Dorota; Trikoupis, Nikolaos

2017-02-01

The monitoring of cryogenic facilities often require the measurement of pressure in the sub 5’000 Pa range that are used for flow metering applications, for saturated superfluid helium, etc. The pressure measurement is based on the minute displacement of a sensing diaphragm often through contactless techniques by using capacitive or inductive methods. The LHC radiation environment forbid the use of standard commercial sensors because of the embedded electronics that are affected both by radiation induced drift and transient Single Event Effects (SEE). Passive pressure sensors from two manufacturers were investigated and a CERN designed radiation-tolerant electronics has been developed for measuring variable-reluctance sensors. During the last maintenance stop of the LHC accelerator, four absolute pressure sensors were installed in some of the low pressure bayonet heat exchangers and four differential pressure sensors on the venturi flowmeters that monitor the cooling flow of the 20.5 kA current leads of the ATLAS end-cap superconducting toroids. The pressure sensors operating range is about 1000 to 5000 Pa and the targeted uncertainty is +/- 50 Pa which would permit to measure the equivalent saturation temperature at 1.8 K within better than 0.01 K. This paper describes the radiation hard measuring head that is based on an inductive bridge, its associated radiation-tolerant electronics that is installed under the LHC superconducting magnets or the ATLAS detector cavern; and the first operational experience.

Helium runaways in white dwarfs

NASA Technical Reports Server (NTRS)

Taam, R. E.

1979-01-01

The long term evolution of an accreting carbon white dwarf was studied from the onset of accretion to the ignition of helium. The variations in the details of the helium shell flash examined with respect to variations in mass accretion rate. For intermediate rates the helium flash is potentially explosive whereas for high rates the shell flash is relatively weak. The results are discussed in the context of the long term evolution of novae.

Digital relief generation from 3D models

NASA Astrophysics Data System (ADS)

Wang, Meili; Sun, Yu; Zhang, Hongming; Qian, Kun; Chang, Jian; He, Dongjian

2016-09-01

It is difficult to extend image-based relief generation to high-relief generation, as the images contain insufficient height information. To generate reliefs from three-dimensional (3D) models, it is necessary to extract the height fields from the model, but this can only generate bas-reliefs. To overcome this problem, an efficient method is proposed to generate bas-reliefs and high-reliefs directly from 3D meshes. To produce relief features that are visually appropriate, the 3D meshes are first scaled. 3D unsharp masking is used to enhance the visual features in the 3D mesh, and average smoothing and Laplacian smoothing are implemented to achieve better smoothing results. A nonlinear variable scaling scheme is then employed to generate the final bas-reliefs and high-reliefs. Using the proposed method, relief models can be generated from arbitrary viewing positions with different gestures and combinations of multiple 3D models. The generated relief models can be printed by 3D printers. The proposed method provides a means of generating both high-reliefs and bas-reliefs in an efficient and effective way under the appropriate scaling factors.

Paramagnetic Attraction of Impurity-Helium Solids

NASA Technical Reports Server (NTRS)

Bernard, E. P.; Boltnev, R. E.; Khmelenko, V. V.; Lee, D. M.

2003-01-01

Impurity-helium solids are formed when a mixture of impurity and helium gases enters a volume of superfluid helium. Typical choices of impurity gas are hydrogen deuteride, deuterium, nitrogen, neon and argon, or a mixture of these. These solids consist of individual impurity atoms and molecules as well as clusters of impurity atoms and molecules covered with layers of solidified helium. The clusters have an imperfect crystalline structure and diameters ranging up to 90 angstroms, depending somewhat on the choice of impurity. Immediately following formation the clusters aggregate into loosely connected porous solids that are submerged in and completely permeated by the liquid helium. Im-He solids are extremely effective at stabilizing high concentrations of free radicals, which can be introduced by applying a high power RF dis- charge to the impurity gas mixture just before it strikes the super fluid helium. Average concentrations of 10(exp 19) nitrogen atoms/cc and 5 x 10(exp 18) deuterium atoms/cc can be achieved this way. It shows a typical sample formed from a mixture of atomic and molecular hydrogen and deuterium. It shows typical sample formed from atomic and molecular nitrogen. Much of the stability of Im-He solids is attributed to their very large surface area to volume ratio and their permeation by super fluid helium. Heat resulting from a chance meeting and recombination of free radicals is quickly dissipated by the super fluid helium instead of thermally promoting the diffusion of other nearby free radicals.

Helium self-trapping and diffusion behaviors in deformed 316L stainless steel exposed to high flux and low energy helium plasma

NASA Astrophysics Data System (ADS)

Gong, Yihao; Jin, Shuoxue; Zhu, Te; Cheng, Long; Cao, Xingzhong; You, Li; Lu, Guanghong; Guo, Liping; Wang, Baoyi

2018-04-01

A large number of dislocation networks were introduced in to 316L stainless steel by cold rolling. Subsequently, low energy (40 eV) helium ions were implanted by exposing the steel to helium plasma. Thermal desorption and positron annihilation spectroscopy were used to study the behavior of helium in the presence of dislocations, with emphasis on helium self-trapping and migration behaviors. Helium desorption behaviour from different helium trapping states was measured by the thermal desorption spectroscopy. Most of the helium desorbed from the He m V n clusters, and the corresponding desorption peak is located at ~650 K. The desorption peak from helium-dislocation clusters (He m D) is at approximately 805 K. The effect of annealing on the defect evolution was investigated by positron annihilation spectroscopy. For the specimen exposed to helium plasma without displacement damage, the increment of S parameter meant the existence of helium self-trapping behavior (He m V n ). Helium atoms could diffuse two to three orders of magnitude deeper than the implantation depth calculated by SRIM. The diffusing helium atoms were gradually trapped by dislocation lines and formed He m D. Elevated temperatures enhance the self-trapping behavior and cause helium atoms to dissociate/desorb from the He m V n clusters, increasing the S parameters at 473-673 K. The gradual recovery of vacancies in the He m V n clusters decreased the S parameter above 673 K.

The High Luminosity LHC Project

NASA Astrophysics Data System (ADS)

Rossi, Lucio

The High Luminosity LHC is one of the major scientific project of the next decade. It aims at increasing the luminosity reach of LHC by a factor five for peak luminosity and a factor ten in integrated luminosity. The project, now fully approved and funded, will be finished in ten years and will prolong the life of LHC until 2035-2040. It implies deep modifications of the LHC for about 1.2 km around the high luminosity insertions of ATLAS and CMS and relies on new cutting edge technologies. We are developing new advanced superconducting magnets capable of reaching 12 T field; superconducting RF crab cavities capable to rotate the beams with great accuracy; 100 kA and hundred meter long superconducting links for removing the power converter out of the tunnel; new collimator concepts, etc... Beside the important physics goals, the High Luminosity LHC project is an ideal test bed for new technologies for the next hadron collider for the post-LHC era.

76 FR 57082 - Premium Penalty Relief; Alternative Premium Funding Target Election Relief

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-15

... PENSION BENEFIT GUARANTY CORPORATION Premium Penalty Relief; Alternative Premium Funding Target... situations involving alternative premium funding target elections. FOR FURTHER INFORMATION CONTACT: Catherine...; Alternative Premium Funding Target Elections; Box 5 Relief).\\1\\ \\1\\ http://www.pbgc.gov/res/other-guidance/tu...

Parametric study on the thermal performance of beam screen samples of the High-Luminosity LHC upgrade

NASA Astrophysics Data System (ADS)

Borges de Sousa, P.; Morrone, M.; Hovenga, N.; Garion, C.; van Weelderen, R.; Koettig, T.; Bremer, J.

2017-12-01

The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) will increase the accelerator’s luminosity by a factor 10 beyond its original design value, giving rise to more collisions and generating an intense flow of debris. A new beam screen has been designed for the inner triplets that incorporates tungsten alloy blocks to shield the superconducting magnets and the 1.9 K superfluid helium bath from incoming radiation. These screens will operate between 60 K and 80 K and are designed to sustain a nominal head load of 15 Wm-1, over 10 times the nominal heat load for the original LHC design. Their overall new and more complex design requires them and their constituent parts to be characterised from a thermal performance standpoint. In this paper we describe the experimental parametric study carried out on two principal thermal components: a representative sample of the beam screen with a tungsten-based alloy block and thermal link and the supporting structure composed of an assembly of ceramic spheres and titanium springs. Results from both studies are shown and discussed regarding their impact on the baseline considerations for the thermal design of the beam screens.

Superfluid helium on orbit transfer (SHOOT)

NASA Technical Reports Server (NTRS)

Dipirro, Michael J.

1987-01-01

A number of space flight experiments and entire facilities require superfluid helium as a coolant. Among these are the Space Infrared Telescope Facility (SIRTF), the Large Deployable Reflector (LDR), the Advanced X-ray Astrophysics Facility (AXAF), the Particle Astrophysics Magnet Facility (PAMF or Astromag), and perhaps even a future Hubble Space Telescope (HST) instrument. Because these systems are required to have long operational lifetimes, a means to replenish the liquid helium, which is exhausted in the cooling process, is required. The most efficient method of replenishment is to refill the helium dewars on orbit with superfluid helium (liquid helium below 2.17 Kelvin). To develop and prove the technology required for this liquid helium refill, a program of ground and flight testing was begun. The flight demonstration is baselined as a two flight program. The first, described in this paper, will prove the concepts involved at both the component and system level. The second flight will demonstrate active astronaut involvement and semi-automated operation. The current target date for the first launch is early 1991.

Fluid relief and check valve

DOEpatents

Blaedel, K.L.; Lord, S.C.; Murray, I.

1986-07-17

A passive fluid pressure relief and check valve allows the relief pressure to be slaved to a reference pressure independently of the exhaust pressure. The pressure relief valve is embodied by a submerged vent line in a sealing fluid, the relief pressure being a function of the submerged depth. A check valve is embodied by a vertical column of fluid (the maximum back pressure being a function of the height of the column of fluid). The pressure is vented into an exhaust system which keeps the exhaust out of the area providing the reference pressure.

Using tevatron magnets for HE-LHC or new ring in LHC tunnel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piekarz, Henryk; /Fermilab

Two injector accelerator options for HE-LHC of p{sup +} - p{sup +} collisions at 33 TeV cms energy are briefly outlined. One option is based on the Super-SPS (S-SPS) accelerator in the SPS tunnel, and the other one is based on the LER (Low-Energy-Ring) accelerator in the LHC tunnel. Expectations of performance of the main arc accelerator magnets considered for the construction of the S-SPS and of the LER accelerators are used to tentatively devise some selected properties of these accelerators as potential injectors to HE-LHC.

Backscattered helium spectroscopy in the helium ion microscope: Principles, resolution and applications

NASA Astrophysics Data System (ADS)

van Gastel, R.; Hlawacek, G.; Dutta, S.; Poelsema, B.

2015-02-01

We demonstrate the possibilities and limitations for microstructure characterization using backscattered particles from a sharply focused helium ion beam. The interaction of helium ions with matter enables the imaging, spectroscopic characterization, as well as the nanometer scale modification of samples. The contrast that is seen in helium ion microscopy (HIM) images differs from that in scanning electron microscopy (SEM) and is generally a result of the higher surface sensitivity of the method. It allows, for instance, a much better visualization of low-Z materials as a result of the small secondary electron escape depth. However, the same differences in beam interaction that give HIM an edge over other imaging techniques, also impose limitations for spectroscopic applications using backscattered particles. Here we quantify those limitations and discuss opportunities to further improve the technique.

Commercial helium reserves, continental rifting and volcanism

NASA Astrophysics Data System (ADS)

Ballentine, C. J.; Barry, P. H.; Hillegonds, D.; Fontijn, K.; Bluett, J.; Abraham-James, T.; Danabalan, D.; Gluyas, J.; Brennwald, M. S.; Pluess, B.; Seneshens, D.; Sherwood Lollar, B.

2017-12-01

Helium has many industrial applications, but notably provides the unique cooling medium for superconducting magnets in medical MRI scanners and high energy beam lines. In 2013 the global supply chainfailed to meet demand causing significant concern - the `Liquid Helium Crisis' [1]. The 2017 closure of Quatar borders, a major helium supplier, is likely to further disrupt helium supply, and accentuates the urgent need to diversify supply. Helium is found in very few natural gas reservoirs that have focused 4He produced by the dispersed decay (a-particle) of U and Th in the crust. We show here, using the example of the Rukwa section of the Tanzanian East African Rift, how continental rifting and local volcanism provides the combination of processes required to generate helium reserves. The ancient continental crust provides the source of 4He. Rifting and associated magmatism provides the tectonic and thermal mechanism to mobilise deep fluid circulation, focusing flow to the near surface along major basement faults. Helium-rich springs in the Tanzanian Great Rift Valley were first identified in the 1950's[2]. The isotopic compositions and major element chemistry of the gases from springs and seeps are consistent with their release from the crystalline basement during rifting [3]. Within the Rukwa Rift Valley, helium seeps occur in the vicinity of trapping structures that have the potential to store significant reserves of helium [3]. Soil gas surveys over 6 prospective trapping structures (1m depth, n=1486) show helium anomalies in 5 out of the 6 at levels similar to those observed over a known helium-rich gas reservoir at 1200m depth (7% He - Harley Dome, Utah). Detailed macroseep gas compositions collected over two days (n=17) at one site allows us to distinguish shallow gas contributions and shows the deep gas to contain between 8-10% helium, significantly increasing resource estimates based on uncorrected values (1.8-4.2%)[2,3]. The remainder of the deep gas is

Development and Dissemination of a Nationwide Helium Database for a National Assessment of Helium Resources.

NASA Astrophysics Data System (ADS)

Brennan, S. T.; East, J. A., II; Garrity, C. P.

2015-12-01

In 2013, Congress passed the Helium Stewardship Act requiring the U.S. Geological Survey (USGS) to undertake a national helium gas resource assessment to determine the nation's helium resources. An important initial component necessary to complete this assessment was the development of a comprehensive database of Helium (He) concentrations from petroleum exploration wells. Because Helium is often used as the carrier gas for compositional analyses for commercial and exploratory oil and gas wells, this limits the available helium concentration data. A literature search in peer-reviewed publications, state geologic survey databases, USGS energy geochemical databases, and the Bureau of Land Management databases provided approximately 16,000 data points from wells that had measurable He concentrations in the gas composition analyses. The data from these wells includes, date of sample collection, American Petroleum Institute well number, formation name, field name, depth of sample collection, and location. The gas compositional analyses, some performed as far back as 1934, do not all have the same level of precision and accuracy, therefore the date of the analysis is critical to the assessment as it indicates the relative amount of uncertainty in the analytical results. Non-proprietary data was used to create a GIS based interactive web interface that allows users to visualize, inspect, interact, and download our most current He data. The user can click on individual locations to see the available data at that location, as well as zoom in and out on a data density map. Concentrations on the map range from .04 mol% (lowest concentration of economic value) to 12% (highest naturally occurring values). This visual interface will allow users to develop a rapid appreciation of the areas with the highest potential for high helium concentrations within oil and gas fields.

Photo-electron emission directly in superfluid helium

NASA Astrophysics Data System (ADS)

Zavyalov, V. V.; Pyurbeeva, E. B.; Khaldeev, S. I.

2018-03-01

Despite the fact that electron transport in condensed helium has been studied for over half a century [1], observations of new intriguing effects still appear [2]. Alas, the traditional methods of injecting electrons into condensed helium (radioactive-sources, electrical discharge or field emission) lead to generation of helium ions, recombination of which is accompanied by emergence of a large number of excitations. As a result, interpretation of such experiments is not simple and sometimes may be questionable. In this respect, photoelectron emitters, which operate with energies substantially smaller than the ionization energy of helium, are preferable. However, immersion of the photocathode into condensed helium suppresses electron emission. Nevertheless, we managed to achieve electron currents (>20 fA) with the In photocathode immersed directly in liquid superfluid helium. The UV light (λ=254 nm) was guided to the photocathode through a two-meter long Al-covered quartz optical fiber.

How to make Raman-inactive helium visible in Raman spectra of tritium-helium gas mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schloesser, M.; Pakari, O.; Rupp, S.

2015-03-15

Raman spectroscopy, a powerful method for the quantitative compositional analysis of molecular gases, e.g. mixtures of hydrogen isotopologues, is not able to detect monoatomic species like helium. This deficit can be overcome by using radioluminescence emission from helium atoms induced by β-electrons from tritium decay. We present theoretical considerations and combined Raman/radioluminescence spectra. Furthermore, we discuss the linearity of the method together with validation measurements for determining the pressure dependence. Finally, we conclude how this technique can be used for samples of helium with traces of tritium, and vice versa. (authors)

LOX Tank Helium Removal for Propellant Scavenging

NASA Technical Reports Server (NTRS)

Chato, David J.

2009-01-01

System studies have shown a significant advantage to reusing the hydrogen and oxygen left in these tanks after landing on the Moon in fuel cells to generate power and water for surface systems. However in the current lander concepts, the helium used to pressurize the oxygen tank can substantially degrade fuel cell power and water output by covering the reacting surface with inert gas. This presentation documents an experimental investigation of methods to remove the helium pressurant while minimizing the amount of the oxygen lost. This investigation demonstrated that significant quantities of Helium (greater than 90% mole fraction) remain in the tank after draining. Although a single vent cycle reduced the helium quantity, large amounts of helium remained. Cyclic venting appeared to be more effective. Three vent cycles were sufficient to reduce the helium to small (less than 0.2%) quantities. Two vent cycles may be sufficient since once the tank has been brought up to pressure after the second vent cycle the helium concentration has been reduced to the less than 0.2% level. The re-pressurization process seemed to contribute to diluting helium. This is as expected since in order to raise the pressure liquid oxygen must be evaporated. Estimated liquid oxygen loss is on the order of 82 pounds (assuming the third vent cycle is not required).

Global helium particle balance in LHD

NASA Astrophysics Data System (ADS)

Motojima, G.; Masuzaki, S.; Tokitani, M.; Kasahara, H.; Yoshimura, Y.; Kobayashi, M.; Sakamoto, R.; Morisaki, T.; Miyazawa, J.; Akiyama, T.; Ohno, N.; Mutoh, T.; Yamada, H.; LHD Experiment Group

2015-08-01

Global helium particle balance in long-pulse discharges is analyzed for the first time in the Large Helical Device (LHD) with the plasma-facing components of the first wall and the divertor tiles composed of stainless steel and carbon, respectively. During the 2-min discharge sustained by ion cyclotron resonance heating (ICRH) and electron cyclotron heating (ECH), helium is observed to be highly retained in the wall (regarded as both the first wall and the divertor tiles). Almost all (about 96%) puffed helium particles (1.3 × 1022 He) are absorbed in the wall near the end of the discharge. Even though a dynamic retention is eliminated, 56% is still absorbed. The analysis is also applied to longer pulse discharges over 40 min by ICRH and ECH, indicating that the helium wall retention is dynamically changed in time. At the initial phase of the discharge, a mechanism for adsorbing helium other than dynamical retention is invoked.

Dynamic Simulation of a Helium Liquefier

NASA Astrophysics Data System (ADS)

Maekawa, R.; Ooba, K.; Nobutoki, M.; Mito, T.

2004-06-01

Dynamic behavior of a helium liquefier has been studied in detail with a Cryogenic Process REal-time SimulaTor (C-PREST) at the National Institute for Fusion Science (NIFS). The C-PREST is being developed to integrate large-scale helium cryogenic plant design, operation and maintenance for optimum process establishment. As a first step of simulations of cooldown to 4.5 K with the helium liquefier model is conducted, which provides a plant-process validation platform. The helium liquefier consists of seven heat exchangers, a liquid-nitrogen (LN2) precooler, two expansion turbines and a liquid-helium (LHe) reservoir. Process simulations are fulfilled with sequence programs, which were implemented with C-PREST based on an existing liquefier operation. The interactions of a JT valve, a JT-bypass valve and a reservoir-return valve have been dynamically simulated. The paper discusses various aspects of refrigeration process simulation, including its difficulties such as a balance between complexity of the adopted models and CPU time.

Helium as a Dynamical Tracer in the Thermosphere

NASA Astrophysics Data System (ADS)

Thayer, J. P.; Liu, X.; Wang, W.; Burns, A. G.

2014-12-01

Helium has been a missing constituent in current thermosphere general circulation models. Although typically a minor gas relative to the more abundant major gasses, its unique properties of being chemically inert and light make it an excellent tracer of thermosphere dynamics. Studying helium can help simplify understanding of transport effects. This understanding can then be projected to other gasses whose overall structure and behavior are complex but, by contrasting with helium, can be evaluated for its transport dependencies. The dynamical influences on composition impact estimates of thermosphere mass density, where helium during solar minima can have a direct contribution, as well as ionosphere electron density. Furthermore, helium estimates in the upper thermosphere during solar minima have not been observed since the 1976 minimum. Indirect estimates of helium in the upper thermosphere during the recent extreme solar minimum indicates winter-time helium concentrations exceeded NRL-MSISE00 estimates by 30%-70% during periods of quiet geomagnetic activity. For times of active geomagnetic conditions, helium concentrations near ~450 km altitude are estimated to decrease while oxygen concentrations increase. An investigation of the altitude structure in thermosphere mass density storm-time perturbations reveal the important effects of composition change with maximum perturbation occurring near the He/O transition region and a much weaker maximum occurring near the O/N2 transition region. However, evaluating helium behavior and its role as a dynamical tracer is not straightforward and model development is necessary to adequately establish the connection to specific dynamical processes. Fortunately recent efforts have led to the implementation of helium modules in the NCAR TIEGCM and TIME-GCM. In this invited talk, the simulated helium behavior and structure will be shown to reproduce observations (such as the wintertime helium bulge and storm-time response) and its

Helium Evolution from the Transfer of Helium Saturated Propellant in Space

NASA Technical Reports Server (NTRS)

Nguyen, Bich N.

2000-01-01

Helium evolution from the transfer of helium saturated propellant in space is quantified to determine its impact from creating a two-phase mixture in the transfer line. The transfer line is approximately 1/2 inch in diameter and 2400 inches in length comprised of the Fluid Interconnect System (FICS), the Orbiter Propellant Transfer System (OPTS) and the International Space Station (ISS) Propulsion Module (ISSPM). The propellant transfer rate is approximately two to three gallons per minute, and the supply tank pressure is maintained at approximately 250 psig.

High efficiency pump for space helium transfer

NASA Technical Reports Server (NTRS)

Hasenbein, Robert; Izenson, Michael G.; Swift, Walter L.; Sixsmith, Herbert

1991-01-01

A centrifugal pump was developed for the efficient and reliable transfer of liquid helium in space. The pump can be used to refill cryostats on orbiting satellites which use liquid helium for refrigeration at extremely low temperatures. The pump meets the head and flow requirements of on-orbit helium transfer: a flow rate of 800 L/hr at a head of 128 J/kg. The overall pump efficiency at the design point is 0.45. The design head and flow requirements are met with zero net positive suction head, which is the condition in an orbiting helium supply Dewar. The mass transfer efficiency calculated for a space transfer operation is 0.99. Steel ball bearings are used with gas fiber-reinforced teflon retainers to provide solid lubrication. These bearings have demonstrated the longest life in liquid helium endurance tests under simulated pumping conditions. Technology developed in the project also has application for liquid helium circulation in terrestrial facilities and for transfer of cryogenic rocket propellants in space.

Helium induced fine structure in the electronic spectra of anthracene derivatives doped into superfluid helium nanodroplets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pentlehner, D.; Slenczka, A., E-mail: alkwin.slenczka@chemie.uni-regensburg.de

2015-01-07

Electronic spectra of organic molecules doped into superfluid helium nanodroplets show characteristic features induced by the helium environment. Besides a solvent induced shift of the electronic transition frequency, in many cases, a spectral fine structure can be resolved for electronic and vibronic transitions which goes beyond the expected feature of a zero phonon line accompanied by a phonon wing as known from matrix isolation spectroscopy. The spectral shape of the zero phonon line and the helium induced phonon wing depends strongly on the dopant species. Phonon wings, for example, are reported ranging from single or multiple sharp transitions to broadmore » (Δν > 100 cm{sup −1}) diffuse signals. Despite the large number of example spectra in the literature, a quantitative understanding of the helium induced fine structure of the zero phonon line and the phonon wing is missing. Our approach is a systematic investigation of related molecular compounds, which may help to shed light on this key feature of microsolvation in superfluid helium droplets. This paper is part of a comparative study of the helium induced fine structure observed in electronic spectra of anthracene derivatives with particular emphasis on a spectrally sharp multiplet splitting at the electronic origin. In addition to previously discussed species, 9-cyanoanthracene and 9-chloroanthracene will be presented in this study for the first time.« less

A new helium gas bearing turboexpander

NASA Astrophysics Data System (ADS)

Xiong, L. Y.; Chen, C. Z.; Liu, L. Q.; Hou, Y.; Wang, J.; Lin, M. F.

2002-05-01

A new helium gas bearing turboexpander of a helium refrigeration system used for space environment simulation experiments is described in this paper. The main design parameters and construction type of some key parts are presented. An improved calculation of thermodynamic efficiency and instability speed of this turboexpander has been obtained by a multiple objects optimization program. Experiments of examining mechanical and thermodynamic performance have been repeatedly conducted in the laboratory by using air at ambient and liquid nitrogen temperature, respectively. In order to predict the helium turboexpander performance, a similarity principles study has been developed. According to the laboratory and on-the-spot experiments, the mechanical and thermodynamic performances of this helium turboexpander are excellent.

Nanofabrication with a helium ion microscope

NASA Astrophysics Data System (ADS)

Maas, Diederik; van Veldhoven, Emile; Chen, Ping; Sidorkin, Vadim; Salemink, Huub; van der Drift, Emile..; Alkemade, Paul

2010-03-01

The recently introduced helium ion microscope (HIM) is capable of imaging and fabrication of nanostructures thanks to its sub-nanometer sized ion probe. The unique interaction of the helium ions with the sample material provides very localized secondary electron emission, thus providing a valuable signal for high-resolution imaging as well as a mechanism for very precise nanofabrication. The low proximity effects, due to the low yield of backscattered ions and the confinement of the forward scattered ions into a narrow cone, enable patterning of ultra-dense sub-10 nm structures. This paper presents various nanofabrication results obtained with direct-write, with scanning helium ion beam lithography, and with helium ion beam induced deposition.

Performance of the CMS precision electromagnetic calorimeter at LHC Run II and prospects for High-Luminosity LHC

NASA Astrophysics Data System (ADS)

Zhang, Zhicai

2018-04-01

Many physics analyses using the Compact Muon Solenoid (CMS) detector at the LHC require accurate, high-resolution electron and photon energy measurements. Following the excellent performance achieved during LHC Run I at center-of-mass energies of 7 and 8 TeV, the CMS electromagnetic calorimeter (ECAL) is operating at the LHC with proton-proton collisions at 13 TeV center-of-mass energy. The instantaneous luminosity delivered by the LHC during Run II has achieved unprecedented levels. The average number of concurrent proton-proton collisions per bunch-crossing (pileup) has reached up to 40 interactions in 2016 and may increase further in 2017. These high pileup levels necessitate a retuning of the ECAL readout and trigger thresholds and reconstruction algorithms. In addition, the energy response of the detector must be precisely calibrated and monitored. We present new reconstruction algorithms and calibration strategies that were implemented to maintain the excellent performance of the CMS ECAL throughout Run II. We will show performance results from the 2015-2016 data taking periods and provide an outlook on the expected Run II performance in the years to come. Beyond the LHC, challenging running conditions for CMS are expected after the High-Luminosity upgrade of the LHC (HL-LHC) . We review the design and R&D studies for the CMS ECAL and present first test beam studies. Particular challenges at HL-LHC are the harsh radiation environment, the increasing data rates, and the extreme level of pile-up events, with up to 200 simultaneous proton-proton collisions. We present test beam results of hadron irradiated PbWO crystals up to fluences expected at the HL-LHC . We also report on the R&D for the new readout and trigger electronics, which must be upgraded due to the increased trigger and latency requirements at the HL-LHC.

Molecular dynamics modeling of helium bubbles in austenitic steels

NASA Astrophysics Data System (ADS)

Jelea, A.

2018-06-01

The austenitic steel devices from pressurized water reactors are continuously subjected to neutron irradiation that produces crystalline point defects and helium atoms in the steel matrix. These species evolve into large defects such as dislocation loops and helium filled bubbles. This paper analyzes, through molecular dynamics simulations with recently developed interatomic potentials, the impact of the helium/steel interface on the helium behavior in nanosize bubbles trapped in an austenitic steel matrix. It is shown that the repulsive helium-steel interactions induce higher pressures in the bubble compared to bulk helium at the same temperature and average density. A new equation of state for helium is proposed in order to take into account these interface effects.

The adsorption of helium atoms on coronene cations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurzthaler, Thomas; Rasul, Bilal; Kuhn, Martin

2016-08-14

We report the first experimental study of the attachment of multiple foreign atoms to a cationic polycyclic aromatic hydrocarbon (PAH). The chosen PAH was coronene, C{sub 24}H{sub 12}, which was added to liquid helium nanodroplets and then subjected to electron bombardment. Using mass spectrometry, coronene cations decorated with helium atoms were clearly seen and the spectrum shows peaks with anomalously high intensities (“magic number” peaks), which represent ion-helium complexes with added stability. The data suggest the formation of a rigid helium layer consisting of 38 helium atoms that completely cover both faces of the coronene ion. Additional magic numbers canmore » be seen for the further addition of 3 and 6 helium atoms, which are thought to attach to the edge of the coronene. The observation of magic numbers for the addition of 38 and 44 helium atoms is in good agreement with a recent path integral Monte Carlo prediction for helium atoms on neutral coronene. An understanding of how atoms and molecules attach to PAH ions is important for a number of reasons including the potential role such complexes might play in the chemistry of the interstellar medium.« less

Helium sell-off risks future supply

NASA Astrophysics Data System (ADS)

Banks, Michael

2010-03-01

The US must stop selling off its helium reserves so that the country has enough of the gas to meet the needs of researchers and medical programmes, warns a report by the National Academy of Sciences (NAS). The report, entitled "Selling the Nation's Helium Reserve", says that failure to halt the sale of helium could lead to a drop in supply of the gas, which is vital for research into magnetic resonance imaging (MRI) techniques and low-temperature physics.

Approximating the Helium Wavefunction in Positronium-Helium Scattering

NASA Technical Reports Server (NTRS)

DiRienzi, Joseph; Drachman, Richard J.

2003-01-01

In the Kohn variational treatment of the positronium- hydrogen scattering problem the scattering wave function is approximated by an expansion in some appropriate basis set, but the target and projectile wave functions are known exactly. In the positronium-helium case, however, a difficulty immediately arises in that the wave function of the helium target atom is not known exactly, and there are several ways to deal with the associated eigenvalue in formulating the variational scattering equations to be solved. In this work we will use the Kohn variational principle in the static exchange approximation to d e t e e the zero-energy scattering length for the Ps-He system, using a suite of approximate target functions. The results we obtain will be compared with each other and with corresponding values found by other approximation techniques.

78 FR 19136 - Emergency Relief Program

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-29

... implementation of the Federal Transit Administration's (FTA) Public Transportation Emergency Relief Program under...-21, Pub. L. 112-141) authorized the Public Transportation Emergency Relief Program at 49 U.S.C. 5324. The Emergency Relief Program allows FTA to make grants for eligible public transportation capital and...

Commissioning of a new helium pipeline

NASA Technical Reports Server (NTRS)

2000-01-01

At the commissioning of a new high-pressure helium pipeline at Kennedy Space Center, participants cut the lines to helium-filled balloons. From left, they are Center Director Roy Bridges; Michael Butchko, president, SGS; Pierre Dufour, president and CEO, Air Liquide America Corporation; David Herst, director, Delta IV Launch Sites; Pamela Gillespie, executive administrator, office of Congressman Dave Weldon; and Col. Samuel Dick, representative of the 45th Space Wing. The nine-mile-long buried pipeline will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. It will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad. Others at the ceremony were Jerry Jorgensen, pipeline project manager, Space Gateway Support (SGS), and Ramon Lugo, acting executive director, JPMO.

Commissioning of a new helium pipeline

NASA Technical Reports Server (NTRS)

2000-01-01

At the commissioning of a new high-pressure helium pipeline at Kennedy Space Center, participants watch as helium-filled balloons take to the sky after their lines were cut. From left, they are Center Director Roy Bridges; Michael Butchko, president, SGS; Pierre Dufour, president and CEO, Air Liquide America Corporation; David Herst, director, Delta IV Launch Sites; Pamela Gillespie, executive administrator, office of Congressman Dave Weldon; and Col. Samuel Dick, representative of the 45th Space Wing. The nine-mile-long buried pipeline will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. It will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad. Others at the ceremony were Jerry Jorgensen, pipeline project manager, Space Gateway Support (SGS), and Ramon Lugo, acting executive director, JPMO.

Transparent Helium in Stripped Envelope Supernovae

NASA Astrophysics Data System (ADS)

Piro, Anthony L.; Morozova, Viktoriya S.

2014-09-01

Using simple arguments based on photometric light curves and velocity evolution, we propose that some stripped envelope supernovae (SNe) show signs that a significant fraction of their helium is effectively transparent. The main pieces of evidence are the relatively low velocities with little velocity evolution, as are expected deep inside an exploding star, along with temperatures that are too low to ionize helium. This means that the helium should not contribute to the shaping of the main SN light curve, and thus the total helium mass may be difficult to measure from simple light curve modeling. Conversely, such modeling may be more useful for constraining the mass of the carbon/oxygen core of the SN progenitor. Other stripped envelope SNe show higher velocities and larger velocity gradients, which require an additional opacity source (perhaps the mixing of heavier elements or radioactive nickel) to prevent the helium from being transparent. We discuss ways in which similar analysis can provide insights into the differences and similarities between SNe Ib and Ic, which will lead to a better understanding of their respective formation mechanisms.

Helium-Shrouded Planets Artist Concept

NASA Image and Video Library

2015-06-11

Planets having atmospheres rich in helium may be common in our galaxy, according to a new theory based on data from NASA's Spitzer Space Telescope. These planets would be around the mass of Neptune, or lighter, and would orbit close to their stars, basking in their searing heat. According to the new theory, radiation from the stars would boil off hydrogen in the planets' atmospheres. Both hydrogen and helium are common ingredients of gas planets like these. Hydrogen is lighter than helium and thus more likely to escape. After billions of years of losing hydrogen, the planet's atmosphere would become enriched with helium. Scientists predict the planets would appear covered in white or gray clouds. This is in contrast to our own Neptune, which is blue due to the presence of methane. Methane absorbs the color red, leaving blue. Neptune is far from our sun and hasn't lost its hydrogen. The hydrogen bonds with carbon to form methane. This artist's concept depicts a proposed helium-atmosphere planet called GJ 436b, which was found by Spitzer to lack in methane -- a first clue about its lack of hydrogen. The planet orbits every 2.6 days around its star, which is cooler than our sun and thus appears more yellow-orange in color. http://photojournal.jpl.nasa.gov/catalog/PIA19344

Analytical modeling of helium turbomachinery using FORTRAN 77

NASA Astrophysics Data System (ADS)

Balaji, Purushotham

Advanced Generation IV modular reactors, including Very High Temperature Reactors (VHTRs), utilize helium as the working fluid, with a potential for high efficiency power production utilizing helium turbomachinery. Helium is chemically inert and nonradioactive which makes the gas ideal for a nuclear power-plant environment where radioactive leaks are a high concern. These properties of helium gas helps to increase the safety features as well as to decrease the aging process of plant components. The lack of sufficient helium turbomachinery data has made it difficult to study the vital role played by the gas turbine components of these VHTR powered cycles. Therefore, this research work focuses on predicting the performance of helium compressors. A FORTRAN77 program is developed to simulate helium compressor operation, including surge line prediction. The resulting design point and off design performance data can be used to develop compressor map files readable by Numerical Propulsion Simulation Software (NPSS). This multi-physics simulation software that was developed for propulsion system analysis has found applications in simulating power-plant cycles.

Influence of Au ions irradiation damage on helium implanted tungsten

NASA Astrophysics Data System (ADS)

Kong, Fanhang; Qu, Miao; Yan, Sha; Cao, Xingzhong; Peng, Shixiang; Zhang, Ailin; Xue, Jianming; Wang, Yugang; Zhang, Peng; Wang, Baoyi

2017-10-01

The damages of implanted helium ions together with energetic neutrons in tungsten is concerned under the background of nuclear fusion related materials research. Helium is lowly soluble in tungsten and has high binding energy with vacancy. In present work, noble metal Au ions were used to study the synergistic effect of radiation damage and helium implantation. Nano indenter and the Doppler broaden energy spectrum of positron annihilation analysis measurements were used to research the synergy of radiation damage and helium implantation in tungsten. In the helium fluence range of 4.8 × 1015 cm-2-4.8 × 1016 cm-2, vacancies played a role of trappers only at the very beginning of bubble nucleation. The size and density is not determined by vacancies, but the effective capture radius between helium bubbles and scattered helium atoms. Vacancies were occupied by helium bubbles even at the lowest helium fluence, leaving dislocations and helium bubbles co-exist in tungsten materials.

The LHC Experiments

ScienceCinema

Lincoln, Don

2018-01-16

The Large Hadron Collider or LHC is the world’s biggest particle accelerator, but it can only get particles moving very quickly. To make measurements, scientists must employ particle detectors. There are four big detectors at the LHC: ALICE, ATLAS, CMS, and LHCb. In this video, Fermilab’s Dr. Don Lincoln introduces us to these detectors and gives us an idea of each one’s capabilities.

Helium heater design for the helium direct cycle component test facility. [for gas-cooled nuclear reactor power plant

NASA Technical Reports Server (NTRS)

Larson, V. R.; Gunn, S. V.; Lee, J. C.

1975-01-01

The paper describes a helium heater to be used to conduct non-nuclear demonstration tests of the complete power conversion loop for a direct-cycle gas-cooled nuclear reactor power plant. Requirements for the heater include: heating the helium to a 1500 F temperature, operating at a 1000 psia helium pressure, providing a thermal response capability and helium volume similar to that of the nuclear reactor, and a total heater system helium pressure drop of not more than 15 psi. The unique compact heater system design proposed consists of 18 heater modules; air preheaters, compressors, and compressor drive systems; an integral control system; piping; and auxiliary equipment. The heater modules incorporate the dual-concentric-tube 'Variflux' heat exchanger design which provides a controlled heat flux along the entire length of the tube element. The heater design as proposed will meet all system requirements. The heater uses pressurized combustion (50 psia) to provide intensive heat transfer, and to minimize furnace volume and heat storage mass.

A superfluid helium system for an LST IR experiment

NASA Technical Reports Server (NTRS)

Breckenridge, R. W., Jr.; Moore, R. W., Jr.

1975-01-01

The results are presented of a study program directed toward evaluating the problems associated with cooling an LST instrument to 2 K for a year by using superfluid helium as the cooling means. The results include the parametric analysis of systems using helium only, and systems using helium plus a shield cryogen. A baseline system, using helium only is described. The baseline system is sized for an instrument heat leak of 50 mw. It contains 71 Kg of superfluid helium and has a total, filled weight of 217 Kg. A brief assessment of the technical problems associated with a long life, spaceborne superfluid helium storage system is also made. It is concluded that a one year life, superfluid helium cooling system is feasible, pending experimental verification of a suitable low g vent system.

Helium diffusion in the sun

NASA Technical Reports Server (NTRS)

Bahcall, J. N.; Pinsonneault, M. H.

1992-01-01

We calculate improved standard solar models using the new Livermore (OPAL) opacity tables, an accurate (exportable) nuclear energy generation routine which takes account of recent measurements and analyses, and the recent Anders-Grevesse determination of heavy element abundances. We also evaluate directly the effect of the diffusion of helium with respect to hydrogen on the calculated neutrino fluxes, on the primordial solar helium abundance, and on the depth of the convective zone. Helium diffusion increases the predicted event rates by about 0.8 SNU, or 11 percent of the total rate, in the chlorine solar neutrino experiment, by about 3.5 SNU, or 3 percent, in the gallium solar neutrino experiments, and by about 12 percent in the Kamiokande and SNO solar neutrino experiments. The best standard solar model including helium diffusion and the most accurate nuclear parameters, element abundances, and radiative opacity predicts a value of 8.0 SNU +/- 3.0 SNU for the C1-37 experiment and 132 +21/-17 SNU for the Ga - 71 experiment, where the uncertainties include 3 sigma errors for all measured input parameters.

47 CFR 69.727 - Regulatory relief.

Code of Federal Regulations, 2010 CFR

2010-10-01

... customer. (b) Phase II relief. Upon satisfaction of the Phase II triggers specified in §§ 69.709(c) or 69... Pricing Flexibility § 69.727 Regulatory relief. (a) Phase I relief. Upon satisfaction of the Phase I... similarly situated customers; and (ii) The price cap LEC excludes all contract tariff offerings from price...

Helium-3 and helium-4 acceleration by high power laser pulses for hadron therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bulanov, S. S.; Esarey, E.; Schroeder, C. B.

The laser driven acceleration of ions is considered a promising candidate for an ion source for hadron therapy of oncological diseases. Though proton and carbon ion sources are conventionally used for therapy, other light ions can also be utilized. Whereas carbon ions require 400 MeV per nucleon to reach the same penetration depth as 250 MeV protons, helium ions require only 250 MeV per nucleon, which is the lowest energy per nucleon among the light ions (heavier than protons). This fact along with the larger biological damage to cancer cells achieved by helium ions, than that by protons, makes thismore » species an interesting candidate for the laser driven ion source. Two mechanisms (magnetic vortex acceleration and hole-boring radiation pressure acceleration) of PW-class laser driven ion acceleration from liquid and gaseous helium targets are studied with the goal of producing 250 MeV per nucleon helium ion beams that meet the hadron therapy requirements. We show that He3 ions, having almost the same penetration depth as He4 with the same energy per nucleon, require less laser power to be accelerated to the required energy for the hadron therapy.« less

Helium-3 and helium-4 acceleration by high power laser pulses for hadron therapy

DOE PAGES

Bulanov, S. S.; Esarey, E.; Schroeder, C. B.; ...

2015-06-24

The laser driven acceleration of ions is considered a promising candidate for an ion source for hadron therapy of oncological diseases. Though proton and carbon ion sources are conventionally used for therapy, other light ions can also be utilized. Whereas carbon ions require 400 MeV per nucleon to reach the same penetration depth as 250 MeV protons, helium ions require only 250 MeV per nucleon, which is the lowest energy per nucleon among the light ions (heavier than protons). This fact along with the larger biological damage to cancer cells achieved by helium ions, than that by protons, makes thismore » species an interesting candidate for the laser driven ion source. Two mechanisms (magnetic vortex acceleration and hole-boring radiation pressure acceleration) of PW-class laser driven ion acceleration from liquid and gaseous helium targets are studied with the goal of producing 250 MeV per nucleon helium ion beams that meet the hadron therapy requirements. We show that He3 ions, having almost the same penetration depth as He4 with the same energy per nucleon, require less laser power to be accelerated to the required energy for the hadron therapy.« less

Thermal desorption behavior of helium in aged titanium tritide films

NASA Astrophysics Data System (ADS)

Cheng, G. J.; Shi, L. Q.; Zhou, X. S.; Liang, J. H.; Wang, W. D.; Long, X. G.; Yang, B. F.; Peng, S. M.

2015-11-01

The desorption behavior of helium in TiT(1.5∼1.8)-x3Hex film samples (x = 0.0022-0.22) was investigated by thermal desorption technique in vacuum condition in this paper. The thermal helium desorption spectrometry (THDS) of aging titanium tritide films prepared by electron beam evaporation revealed that, depending on the decayed 3He concentration in the samples, there are more than four states of helium existing in the films. The divided four zones in THDS based on helium states represent respectively: (1) the mobile single helium atoms with low activation energy in all aging samples resulted from the interstitial sites or dissociated from interstitial clusters, loops and dislocations, (2) helium bubbles inside the grain lattices, (3) helium bubbles in the grain boundaries and interconnected networks of dislocations in the helium concentration of 3Hegen/Ti > 0.0094, and (4) helium bubbles near or linked to the film surface by interconnected channel for later aging stage with 3Hegen/Ti > 0.18. The proportion of helium desorption in each zone was estimated, and dissociated energies of helium for different trapping states were given.

Advanced helium magnetometer for space applications

NASA Technical Reports Server (NTRS)

Slocum, Robert E.

1987-01-01

The goal of this effort was demonstration of the concepts for an advanced helium magnetometer which meets the demands of future NASA earth orbiting, interplanetary, solar, and interstellar missions. The technical effort focused on optical pumping of helium with tunable solid state lasers. We were able to demonstrate the concept of a laser pumped helium magnetometer with improved accuracy, low power, and sensitivity of the order of 1 pT. A number of technical approaches were investigated for building a solid state laser tunable to the helium absorption line at 1083 nm. The laser selected was an Nd-doped LNA crystal pumped by a diode laser. Two laboratory versions of the lanthanum neodymium hexa-aluminate (LNA) laser were fabricated and used to conduct optical pumping experiments in helium and demonstrate laser pumped magnetometer concepts for both the low field vector mode and the scalar mode of operation. A digital resonance spectrometer was designed and built in order to evaluate the helium resonance signals and observe scalar magnetometer operation. The results indicate that the laser pumped sensor in the VHM mode is 45 times more sensitive than a lamp pumped sensor for identical system noise levels. A study was made of typical laser pumped resonance signals in the conventional magnetic resonance mode. The laser pumped sensor was operated as a scalar magnetometer, and it is concluded that magnetometers with 1 pT sensitivity can be achieved with the use of laser pumping and stable laser pump sources.

LRO-LAMP Observations of Lunar Exospheric Helium

NASA Astrophysics Data System (ADS)

Grava, Cesare; Retherford, Kurt D.; Hurley, Dana M.; Feldman, Paul D.; Gladstone, Randy; Greathouse, Thomas K.; Cook, Jason C.; Stern, Alan; Pryor, Wayne R.; Halekas, Jasper S.; Kaufmann, David E.

2015-11-01

We present results from Lunar Reconnaissance Orbiter’s (LRO) UV spectrograph LAMP (Lyman-Alpha Mapping Project) campaign to study the lunar atmosphere. Two kinds of off-nadir maneuvers (lateral rolls and pitches towards and opposite the direction of motion of LRO) were performed to search for resonantly scattering species, increasing the illuminated line-of-sight (and hence the signal from atoms resonantly scattering the solar photons) compared to previously reported LAMP “twilight observations” [Cook & Stern, 2014]. Helium was the only element distinguishable on a daily basis, and we present latitudinal profiles of its line-of-sight column density in December 2013. We compared the helium line-of-sight column densities with solar wind alpha particle fluxes measured from the ARTEMIS (Acceleration, Reconnection, Turbulence, & Electrodynamics of Moon’s Interaction with the Sun) twin spacecraft. Our data show a correlation with the solar wind alpha particle flux, confirming that the solar wind is the main source of the lunar helium, but not with a 1:1 relationship. Assuming that the lunar soil is saturated with helium atoms, our results suggest that not all of the incident alpha particles are converted to thermalized helium, allowing for a non-negligible fraction (~50 %) to escape as suprathermal helium or simply backscattered from the lunar surface. We also support the finding by Benna et al. [2015] and Hurley et al. [2015], that a non-zero contribution from endogenic helium, coming from radioactive decay of 232Th and 238U within the mantle, is present, and is estimated to be (4.5±1.2) x 106 He atoms cm-2 s-1. Finally, we compare LAMP-derived helium surface density with the one recorded by the mass spectrometer LACE (Lunar Atmospheric Composition Experiment) deployed on the lunar surface during the Apollo 17 mission, finding good agreement between the two measurements. These LRO off-nadir maneuvers allow LAMP to provide unique coverage of local solar time and

LHC Inauguration and LHCFest

ScienceCinema

None

2018-06-26

The LHC official inauguration will take place from 14h00 to 18h00, at Point 18 of the Laboratory, in the presence of the highest representatives from the member states of CERN and representatives from the other communities and authorities of the countries participating in the LHC adventure. 300 members from the international press are also expected, giving a total of 1500 guests. The ceremony will be broadcast live in the Laboratory’s main conference rooms, via webcast and satellite TV (Eurovision). The LHC-fest will follow in the evening in the same place. Its purpose is to, "thank all the actors – physicists, engineers, technicians and administrators – who took part in the design, construction, implementation and commissioning of this great enterprise." For obvious logistical reasons, it has been necessary to limit the number of invited guests to 3000, to include all members of personnel (blue badge holders), representatives of the LHC experiments and other users, as well as representatives from retired staff and industrial support.

Laser induced fluorescence spectroscopy of the Ca dimer deposited on helium and mixed helium/xenon clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaveau, Marc-André; Pothier, Christophe; Briant, Marc

2014-12-09

We study how the laser induced fluorescence spectroscopy of the calcium dimer deposited on pure helium clusters is modified by the addition of xenon atoms. In the wavelength range between 365 and 385 nm, the Ca dimer is excited from its ground state up to two excited electronic states leading to its photodissociation in Ca({sup 1}P)+Ca({sup 1}S): this process is monitored by recording the Ca({sup 1}P) fluorescence at 422.7nm. One of these electronic states of Ca{sub 2} is a diexcited one correlating to the Ca(4s4p{sup 3}P(+Ca(4s3d{sup 3}D), the other one is a repulsive state correlating to the Ca(4s4p1P)+Ca(4s21S) asymptote, accountingmore » for the dissociation of Ca{sub 2} and the observation of the subsequent Ca({sup 1}P) emission. On pure helium clusters, the fluorescence exhibits the calcium atomic resonance line Ca({sup 1}S←{sup 1}P) at 422.7 nm (23652 cm{sup −1}) assigned to ejected calcium, and a narrow red sided band corresponding to calcium that remains solvated on the helium cluster. When adding xenon atoms to the helium clusters, the intensity of these two features decreases and a new spectral band appears on the red side of calcium resonance line; the intensity and the red shift of this component increase along with the xenon quantity deposited on the helium cluster: it is assigned to the emission of Ca({sup 1}P) associated with the small xenon aggregate embedded inside the helium cluster.« less

Commissioning of a new helium pipeline

NASA Technical Reports Server (NTRS)

2000-01-01

Center Director Roy Bridges addresses the audience at the commissioning of a new high-pressure helium pipeline at Kennedy Space Center that will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. The nine-mile- long buried pipeline will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad. Others at the ceremony were Jerry Jorgensen, pipeline project manager, Space Gateway Support (SGS); Col. Samuel Dick, representative of the 45th Space Wing; Ramon Lugo, acting executive director, JPMO; David Herst, director, Delta IV Launch Sites; Pierre Dufour, president and CEO, Air Liquide America Corporation; and Michael Butchko, president, SGS.

Introduction to the HL-LHC Project

NASA Astrophysics Data System (ADS)

Rossi, L.; Brüning, O.

The Large Hadron Collider (LHC) is one of largest scientific instruments ever built. It has been exploring the new energy frontier since 2010, gathering a global user community of 7,000 scientists. To extend its discovery potential, the LHC will need a major upgrade in the 2020s to increase its luminosity (rate of collisions) by a factor of five beyond its design value and the integrated luminosity by a factor of ten. As a highly complex and optimized machine, such an upgrade of the LHC must be carefully studied and requires about ten years to implement. The novel machine configuration, called High Luminosity LHC (HL-LHC), will rely on a number of key innovative technologies, representing exceptional technological challenges, such as cutting-edge 11-12 tesla superconducting magnets, very compact superconducting cavities for beam rotation with ultra-precise phase control, new technology for beam collimation and 300-meter-long high-power superconducting links with negligible energy dissipation. HL-LHC federates efforts and R&D of a large community in Europe, in the US and in Japan, which will facilitate the implementation of the construction phase as a global project.

Cooling-capacity characteristics of Helium-4 JT cryocoolers

NASA Astrophysics Data System (ADS)

Wang, Y. L.; Liu, D. L.; Gan, Z. H.; Guo, Y. X.; Shen, Y. W.; Chen, S. F.

2017-12-01

Cooling capacity of a Helium-4 JT cryocooler may be achieved at a temperature higher than liquid helium temperature. The latent cooling capacity, which should be obtained at liquid helium temperature, is defined as a special part of cooling capacity. With the thermodynamic analysis on steady working conditions of a Helium-4 JT cryocooler, its cooling capacity and temperature characteristics are presented systematically. The effects of precooling temperature and high pressure on the cooling capacity and latent cooling capacity are illustrated. Furthermore, the JT cryocoolers using hydrogen and neon as the working fluids are also discussed. It is shown that helium JT cryocooler has a special cooling capacity characteristic which does not exist in JT cryocoolers using other pure working fluids.

Helium refrigeration considerations for cryomodule design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganni, V.; Knudsen, P.

Many of the present day accelerators are based on superconducting radio frequency (SRF) cavities, packaged in cryo-modules (CM), which depend on helium refrigeration at sub-atmospheric pressures, nominally 2 K. These specialized helium refrigeration systems are quite cost intensive to produce and operate. Particularly as there is typically no work extraction below the 4.5-K supply, it is important that the exergy loss between this temperature level and the CM load temperature(s) be minimized by the process configuration choices. This paper will present, compare and discuss several possible helium distribution process arrangements to support the CM loads.

How to Make a Helium Atmosphere

NASA Image and Video Library

2015-06-11

This diagram illustrates how hypothetical helium atmospheres might form. These would be on planets about the mass of Neptune, or smaller, which orbit tightly to their stars, whipping around in just days. They are thought to have cores of water or rock, surrounded by thick atmospheres of gas. Radiation from their nearby stars would boil off hydrogen and helium, but because hydrogen is lighter, more hydrogen would escape. It's also possible that planetary bodies, such as asteroids, could impact the planet, sending hydrogen out into space. Over time, the atmospheres would become enriched in helium. With less hydrogen in the planets' atmospheres, the concentration of methane and water would go down. Both water and methane consist in part of hydrogen. Eventually, billions of years later (a "Gyr" equals one billion years), the abundances of the water and methane would be greatly reduced. Since hydrogen would not be abundant, the carbon would be forced to pair with oxygen, forming carbon monoxide. NASA's Spitzer Space Telescope observed a proposed helium planet, GJ 436b, with these traits: it lacks methane, and appears to contain carbon monoxide. Future observations are needed to detect helium itself in the atmospheres of these planets, and confirm this theory. http://photojournal.jpl.nasa.gov/catalog/PIA19345

Helium Transfer System for the Superconducting Devices at NSRRC

NASA Astrophysics Data System (ADS)

Li, H. C.; Hsiao, F. Z.; Chang, S. H.; Chiou, W. S.

2006-04-01

A helium cryogenic plant with a maximum cooling power of 450 W at 4.5K was installed at the end of the year 2003. This plant has provide the cooling power for the test of one superconducting cavity and the commission of one superconducting magnet for nine months. In November 2004, we installed one helium transfer system in NSRRC's storage ring to fulfill the cooling requirement for the operation of one superconducting cavity and two superconducting magnets. This helium transfer system consists of a switch valve box and the nitrogen-shielding multi-channel transfer lines. The averaged heat leak to the helium process line (including the straight section, the joint, the elbow, the coupling) at liquid helium temperature is specified to be less than 0.1 W/m at 4.2K; the total heat leak of the switching valve box to helium process lines is less than 16 W at 4.2K. In this paper we present the function, design parameters and test result of the helium transfer system. Commissioning results of both the cavity and the magnets using this helium transfer system will be shown as well.

Helium interactions with alumina formed by atomic layer deposition show potential for mitigating problems with excess helium in spent nuclear fuel

NASA Astrophysics Data System (ADS)

Zhang, Shenli; Yu, Erick; Gates, Sean; Cassata, William S.; Makel, James; Thron, Andrew M.; Bartel, Christopher; Weimer, Alan W.; Faller, Roland; Stroeve, Pieter; Tringe, Joseph W.

2018-02-01

Helium gas accumulation from alpha decay during extended storage of spent fuel has potential to compromise the structural integrity the fuel. Here we report results obtained with surrogate nickel particles which suggest that alumina formed by atomic layer deposition can serve as a low volume-fraction, uniformly-distributed phase for retention of helium generated in fuel particles such as uranium oxide. Thin alumina layers may also form transport paths for helium in the fuel rod, which would otherwise be impermeable. Micron-scale nickel particles, representative of uranium oxide particles in their low helium solubility and compatibility with the alumina synthesis process, were homogeneously coated with alumina approximately 3-20 nm by particle atomic layer deposition (ALD) using a fluidized bed reactor. Particles were then loaded with helium at 800 °C in a tube furnace. Subsequent helium spectroscopy measurements showed that the alumina phase, or more likely a related nickel/alumina interface structure, retains helium at a density of at least 1017 atoms/cm3. High resolution transmission electron microscopy revealed that the thermal treatment increased the alumina thickness and generated additional porosity. Results from Monte Carlo simulations on amorphous alumina predict the helium retention concentration at room temperature could reach 1021 atoms/cm3 at 400 MPa, a pressure predicted by others to be developed in uranium oxide without an alumina secondary phase. This concentration is sufficient to eliminate bubble formation in the nuclear fuel for long-term storage scenarios, for example. Measurements by others of the diffusion coefficient in polycrystalline alumina indicate values several orders of magnitude higher than in uranium oxide, which then can also allow for helium transport out of the spent fuel.

Quantification of fatal helium exposure following self-administration.

PubMed

Malbranque, S; Mauillon, D; Turcant, A; Rouge-Maillart, C; Mangin, P; Varlet, V

2016-11-01

Helium is nontoxic at standard conditions, plays no biological role, and is found in trace amounts in human blood. Helium can be dangerous if inhaled to excess, since it is a simple tissue hypoxia and so displaces the oxygen needed for normal respiration. This report presents a fatal case of a middle-aged male victim who died from self-administered helium exposure. For the first time, the quantification of the helium levels in gastric and lung air and in blood samples was achieved using gas chromatography-mass spectrometry after airtight sampling. The results of the toxicological investigation showed that death was caused directly by helium exposure. However, based on the pathomorphological changes detected during the forensic autopsy, we suppose that the fatal outcome was the result of the lack of oxygen after inhalation.

Commissioning of a new helium pipeline

NASA Technical Reports Server (NTRS)

2000-01-01

At the commissioning of a new high-pressure helium pipeline at Kennedy Space Center, Ramon Lugo, acting executive director, JPMO , presents a plaque to Center Director Roy Bridges. The pipeline will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. Others at the ceremony were Jerry Jorgensen, pipeline project manager, Space Gateway Support (SGS); Col. Samuel Dick, representative of the 45th Space Wing; David Herst, director, Delta IV Launch Sites; Pierre Dufour, president and CEO, Air Liquide America Corporation; and Michael Butchko, president, SGS. The nine-mile-long buried pipeline will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad.

Commissioning of a new helium pipeline

NASA Technical Reports Server (NTRS)

2000-01-01

Jerry Jorgensen, pipeline project manager, Space Gateway Support (SGS) presents an award of appreciation to H.T. Everett, KSC Propellants manager, at the commissioning of a new high-pressure helium pipeline at Kennedy Space Center. The pipeline will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. The nine-mile-long buried pipeline will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad. Others at the ceremony were Center Director Roy Bridges;); Col. Samuel Dick, representative of the 45th Space Wing; Ramon Lugo, acting executive director, JPMO; David Herst, director, Delta IV Launch Sites; Pierre Dufour, president and CEO, Air Liquide America Corporation; and Michael Butchko, president, SGS.

Commissioning of a new helium pipeline

NASA Technical Reports Server (NTRS)

2000-01-01

Jerry Jorgensen welcomes the audience to the commissioning of a new high-pressure helium pipeline at Kennedy Space Center. Jorgensen, with Space Gateway Support (SGS), is the pipeline project manager. To the right is Ramon Lugo, acting executive director, JPMO. Others at the ceremony were Center Director Roy Bridges; Col. Samuel Dick, representative of the 45th Space Wing; David Herst, director, Delta IV Launch Sites; Pierre Dufour, president and CEO, Air Liquide America Corporation; and Michael Butchko, president, SGS. The pipeline will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. The nine-mile-long buried pipeline will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad.

Detection of Charged Particles in Superfluid Helium

NASA Astrophysics Data System (ADS)

Bandler, Simon Richard

1995-01-01

At the present time the measurement of the flux of neutrinos from the sun remains a challenging experimental problem. The ideal detector would be able to detect neutrinos at high rate, in real time, with good energy resolution and would have a threshold which is low enough for investigation of the entire solar neutrino spectrum. A new detection scheme using superfluid helium as a target has been proposed which has the potential to meet most of the criteria of the ideal detector. In this scheme a neutrino would be detected when it elastically scatters off an atomic electron in superfluid helium. The electron loses energy via a number of processes eventually leading to the generation of phonons and rotons in the liquid. At low temperatures these excitations propagate ballistically through the superfluid helium. When the excitations reach the free surface some of them are able to evaporate helium atoms. These atoms can be detected by an array of calorimeters suspended above the liquid surface. In this thesis, results are presented for a small -scale prototype of this type of detector. Experiments have been performed using various radioactive sources to generate energy depositions in the liquid. The results reveal details about the processes of generation of rotons and phonons, the propagation of these excitations through the superfluid, the evaporation of helium atoms and the adsorption of helium atoms onto the wafer. Results are also presented on the detection of fluorescent photons generated in the liquid. One source of energy depositions was 241{rm Am} which produces monoenergetic 5.5 MeV alpha particles. It was found that the ratio of the energy deposited in a calorimeter to the energy deposited in liquid helium was 0.084 when alpha's are emitted parallel to the liquid surface, and 0.020 for alpha's emitted perpendicular. The difference is due to the anisotropic distribution of helium excitations generated. A 113{rm Sn} source of 360 keV electrons stopped in

Safety Aspects of Big Cryogenic Systems Design

NASA Astrophysics Data System (ADS)

Chorowski, M.; Fydrych, J.; Poliński, J.

2010-04-01

Superconductivity and helium cryogenics are key technologies in the construction of large scientific instruments, like accelerators, fusion reactors or free electron lasers. Such cryogenic systems may contain more than hundred tons of helium, mostly in cold and high-density phases. In spite of the high reliability of the systems, accidental loss of the insulation vacuum, pipe rupture or rapid energy dissipation in the cold helium can not be overlooked. To avoid the danger of over-design pressure rise in the cryostats, they need to be equipped with a helium relief system. Such a system is comprised of safety valves, bursting disks and optionally cold or warm quench lines, collectors and storage tanks. Proper design of the helium safety relief system requires a good understanding of worst case scenarios. Such scenarios will be discussed, taking into account different possible failures of the cryogenic system. In any case it is necessary to estimate heat transfer through degraded vacuum superinsulation and mass flow through the valves and safety disks. Even if the design of the helium relief system does not foresee direct helium venting into the environment, an occasional emergency helium spill may happen. Helium propagation in the atmosphere and the origins of oxygen-deficiency hazards will be discussed.

Le LHC, un tunnel cosmique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Binetruy, Pierre

2009-09-17

Et si la lumière au bout du tunnel du LHC était cosmique ? En d’autres termes, qu’est-ce que le LHC peut nous apporter dans la connaissance de l’Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l’univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l’Univers ? La matière noire est-elle détectable au LHC ? L’énergie noire ? Pourquoi l’antimatière accumulée au CERN est-elle si rare dans l’Univers ? Et si le CERNmore » a bâti sa réputation sur l’exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l’évolution cosmique ? Depuis une trentaine d’années, notre compréhension de l’univers dans ses plus grandes dimensions et l’appréhension de son comportement aux plus petites distances sont intimement liées : en quoi le LHC va-t-il tester expérimentalement cette vision unifiée ? Tout public, entrée libre / Réservations au +41 (0)22 767 76 76« less

Who gives pain relief to children?

PubMed Central

Spedding, R L; Harley, D; Dunn, F J; McKinney, L A

1999-01-01

OBJECTIVE: To compare pre-hospital parental administration of pain relief for children with that of the accident and emergency (A&E) department staff and to ascertain the reason why pre-hospital analgesia is not being given. DESIGN/METHODS: An anonymous prospective questionnaire was given to parents/guardians of children < 17 years. The children were all self referred with head injuries or limb problems including burns. The first part asked for details of pain relief before attendance in the A&E department. The second part of the questionnaire contained a section for the examining doctor and triage nurse to fill in. The duration of the survey was 28 days. RESULTS: Altogether 203 of 276 (74%) of children did not receive pain relief before attendance at the A&E department. Reasons for parents not giving pain relief included 57/203 (28%) who thought that giving painkillers would be harmful; 43/203 (21%) who did not give painkillers because the accident did not happen at home; and 15/203 (7%) who thought analgesia was the responsibility of the hospital. Eighty eight of the 276 (32%) did not have any painkillers, suitable for children, at home. A&E staff administered pain relief in 189/276 (68%). CONCLUSIONS: Parents often do not give their children pain relief before attending the A&E department. Parents think that giving painkillers may be harmful and often do not have simple analgesics at home. Some parents do not perceive that their child is in pain. Parents require education about appropriate pre-hospital pain relief for their children. PMID:10417932

Helium resources of the United States, 1993. Information circular/1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamak, J.E.; Driskill, D.L.

1995-12-31

This report uses several criteria to determine reserves, marginal reserves, and subeconomic resources, including helium content, proximity to major gas transmission lines, and size of field. Refinements in evaluating other occurrences of helium and undiscovered resources also have been made for this report. As of this report, there is 33.7 Bcf of helium stored in Bush Dome at Cliffside Gasfield. The USBM owns 31.7 Bcf, and 2.0 Bcf is owned by private companies. There is also approximately 3.8 Bcf of helium contained in the natural gas in Bush Dome. This reserve of helium and the helium on Federal lands inmore » nondepleting fields will fulfill the USBM`s mission of supplying helium to meet all essential Government needs for several decades.« less

49 CFR 178.345-10 - Pressure relief.

Code of Federal Regulations, 2010 CFR

2010-10-01

... applicable individual specification. The pressure and vacuum relief system must be designed to operate and... resulting from loading, unloading, or from heating and cooling of lading. Pressure relief systems are not required to conform to the ASME Code. (b) Type and construction of relief systems and devices. (1) Each...

Capacity enhancement of indigenous expansion engine based helium liquefier

NASA Astrophysics Data System (ADS)

Doohan, R. S.; Kush, P. K.; Maheshwari, G.

2017-02-01

Development of technology and understanding for large capacity helium refrigeration and liquefaction at helium temperature is indispensable for coming-up projects. A new version of helium liquefier designed and built to provide approximately 35 liters of liquid helium per hour. The refrigeration capacity of this reciprocating type expansion engine machine has been increased from its predecessor version with continuous improvement and deficiency debugging. The helium liquefier has been built using components by local industries including cryogenic Aluminum plate fin heat exchangers. Two compressors with nearly identical capacity have been deployed for the operation of system. Together they consume about 110 kW of electric power. The system employs liquid Nitrogen precooling to enhance liquid Helium yield. This paper describes details of the cryogenic expander design improvements, reconfiguration of heat exchangers, performance simulation and their experimental validation.

Feasibility of lunar Helium-3 mining

NASA Astrophysics Data System (ADS)

Kleinschneider, Andreas; Van Overstraeten, Dmitry; Van der Reijnst, Roy; Van Hoorn, Niels; Lamers, Marvin; Hubert, Laurent; Dijk, Bert; Blangé, Joey; Hogeveen, Joel; De Boer, Lennaert; Noomen, Ron

With fossil fuels running out and global energy demand increasing, the need for alternative energy sources is apparent. Nuclear fusion using Helium-3 may be a solution. Helium-3 is a rare isotope on Earth, but it is abundant on the Moon. Throughout the space community lunar Helium-3 is often cited as a major reason to return to the Moon. Despite the potential of lunar Helium-3 mining, little research has been conducted on a full end-to-end mission. This abstract presents the results of a feasibility study conducted by students from Delft University of Technology. The goal of the study was to assess whether a continuous end-to-end mission to mine Helium-3 on the Moon and return it to Earth is a viable option for the future energy market. The set requirements for the representative end-to-end mission were to provide 10% of the global energy demand in the year 2040. The mission elements have been selected with multiple trade-offs among both conservative and novel concepts. A mission architecture with multiple decoupled elements for each transportation segment (LEO, transfer, lunar surface) was found to be the best option. It was found that the most critical element is the lunar mining operation itself. To supply 10% of the global energy demand in 2040, 200 tons of Helium-3 would be required per year. The resulting regolith mining rate would be 630 tons per second, based on an optimistic concentration of 20 ppb Helium-3 in lunar regolith. Between 1,700 to 2,000 Helium-3 mining vehicles would be required, if using University of Wisconsin’s Mark III miner. The required heating power, if mining both day and night, would add up to 39 GW. The resulting power system mass for the lunar operations would be in the order of 60,000 to 200,000 tons. A fleet of three lunar ascent/descent vehicles and 22 continuous-thrust vehicles for orbit transfer would be required. The costs of the mission elements have been spread out over expected lifetimes. The resulting profits from Helium

46 CFR 64.59 - Spring loaded pressure relief valve.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59 Spring loaded pressure relief valve. A spring loaded pressure relief valve must— (a) Be set at a nominal...

46 CFR 64.59 - Spring loaded pressure relief valve.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59 Spring loaded pressure relief valve. A spring loaded pressure relief valve must— (a) Be set at a nominal...

46 CFR 64.59 - Spring loaded pressure relief valve.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59 Spring loaded pressure relief valve. A spring loaded pressure relief valve must— (a) Be set at a nominal...

46 CFR 64.59 - Spring loaded pressure relief valve.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59 Spring loaded pressure relief valve. A spring loaded pressure relief valve must— (a) Be set at a nominal...

46 CFR 64.59 - Spring loaded pressure relief valve.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59 Spring loaded pressure relief valve. A spring loaded pressure relief valve must— (a) Be set at a nominal...

Liquid Oxygen Thermodynamic Vent System Testing with Helium Pressurization

NASA Technical Reports Server (NTRS)

VanDresar, Neil T.

2014-01-01

This report presents the results of several thermodynamic vent system (TVS) tests with liquid oxygen plus a test with liquid nitrogen. In all tests, the liquid was heated above its normal boiling point to 111 K for oxygen and 100 K for nitrogen. The elevated temperature was representative of tank conditions for a candidate lunar lander ascent stage. An initial test series was conducted with saturated oxygen liquid and vapor at 0.6 MPa. The initial series was followed by tests where the test tank was pressurized with gaseous helium to 1.4 to 1.6 MPa. For these tests, the helium mole fraction in the ullage was quite high, about 0.57 to 0.62. TVS behavior is different when helium is present than when helium is absent. The tank pressure becomes the sum of the vapor pressure and the partial pressure of helium. Therefore, tank pressure depends not only on temperature, as is the case for a pure liquid-vapor system, but also on helium density (i.e., the mass of helium divided by the ullage volume). Thus, properly controlling TVS operation is more challenging with helium pressurization than without helium pressurization. When helium was present, the liquid temperature would rise with each successive TVS cycle if tank pressure was kept within a constant control band. Alternatively, if the liquid temperature was maintained within a constant TVS control band, the tank pressure would drop with each TVS cycle. The final test series, which was conducted with liquid nitrogen pressurized with helium, demonstrated simultaneous pressure and temperature control during TVS operation. The simultaneous control was achieved by systematic injection of additional helium during each TVS cycle. Adding helium maintained the helium partial pressure as the liquid volume decreased because of TVS operation. The TVS demonstrations with liquid oxygen pressurized with helium were conducted with three different fluid-mixer configurations-a submerged axial jet mixer, a pair of spray hoops in the tank

Injuries sustained by earthquake relief workers: a retrospective analysis of 207 relief workers during Nepal earthquake.

PubMed

Du, Feizhou; Wu, Jialing; Fan, Jin; Jiang, Rui; Gu, Ming; He, Xiaowu; Wang, Zhiming; He, Ci

2016-07-26

This study aimed to analyse the injuries sustained by rescue workers in earthquake relief efforts in high altitude areas for improving the ways of how to effectively prevent the injuries. The clinical data of 207 relief workers from four military hospitals in Tibet, who were injured in the Tibetan disaster areas of China during '4.25' Nepal earthquake rescue period, was retrospectively analyzed. The demographic features, sites of injury and causes of injury were investigated. The most frequently injured sites were the ankle-foot and hand-wrist (n = 61, 26.5 %), followed by injuries in leg-knee-calf (n = 22, 9.6 %), head-neck (4.87 %), thoracic and abdominal region (2.6 %) and lower back (3.9 %). The specific high-altitude environment increased the challenges associated with earthquake relief. The specific plateau environment and climate increased the burden and challenge in earthquake relief. The injury distribution data shown in this study demonstrated that effective organization and personnel protection can reduce the injury occurrences. Relief workers were prone to suffering various injuries and diseases under specific high-altitude environment.

49 CFR 178.345-10 - Pressure relief.

Code of Federal Regulations, 2012 CFR

2012-10-01

... cargo tank must be provided with a primary pressure relief system consisting of one or more reclosing... parallel with the primary pressure relief system may be used to augment the total venting capacity of the cargo tank. Non-reclosing pressure relief devices are not authorized in any cargo tank except when in...

49 CFR 178.345-10 - Pressure relief.

Code of Federal Regulations, 2011 CFR

2011-10-01

... cargo tank must be provided with a primary pressure relief system consisting of one or more reclosing... parallel with the primary pressure relief system may be used to augment the total venting capacity of the cargo tank. Non-reclosing pressure relief devices are not authorized in any cargo tank except when in...

49 CFR 178.345-10 - Pressure relief.

Code of Federal Regulations, 2014 CFR

2014-10-01

... cargo tank must be provided with a primary pressure relief system consisting of one or more reclosing... parallel with the primary pressure relief system may be used to augment the total venting capacity of the cargo tank. Non-reclosing pressure relief devices are not authorized in any cargo tank except when in...

49 CFR 178.345-10 - Pressure relief.

Code of Federal Regulations, 2013 CFR

2013-10-01

... cargo tank must be provided with a primary pressure relief system consisting of one or more reclosing... parallel with the primary pressure relief system may be used to augment the total venting capacity of the cargo tank. Non-reclosing pressure relief devices are not authorized in any cargo tank except when in...

High Luminosity LHC: challenges and plans

NASA Astrophysics Data System (ADS)

Arduini, G.; Barranco, J.; Bertarelli, A.; Biancacci, N.; Bruce, R.; Brüning, O.; Buffat, X.; Cai, Y.; Carver, L. R.; Fartoukh, S.; Giovannozzi, M.; Iadarola, G.; Li, K.; Lechner, A.; Medina Medrano, L.; Métral, E.; Nosochkov, Y.; Papaphilippou, Y.; Pellegrini, D.; Pieloni, T.; Qiang, J.; Redaelli, S.; Romano, A.; Rossi, L.; Rumolo, G.; Salvant, B.; Schenk, M.; Tambasco, C.; Tomás, R.; Valishev, S.; Van der Veken, F. F.

2016-12-01

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will undergo a major upgrade in the 2020s. This will increase its rate of collisions by a factor of five beyond the original design value and the integrated luminosity by a factor ten. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 T superconducting magnets, including Nb3Sn-based magnets never used in accelerators before, compact superconducting cavities for longitudinal beam rotation, new technology and physical processes for beam collimation. The dynamics of the HL-LHC beams will be also particularly challenging and this aspect is the main focus of this paper.

Tritium Decay Helium-3 Effects in Tungsten

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shimada, M.; Merrill, B. J.

2016-06-01

A critical challenge for long-term operation of ITER and beyond to a Demonstration reactor (DEMO) and future fusion reactor will be the development of plasma-facing components (PFCs) that demonstrate erosion resistance to steady-state/transient heat fluxes and intense neutral/ion particle fluxes under the extreme fusion nuclear environment, while at the same time minimizing in-vessel tritium inventories and permeation fluxes into the PFC’s coolant. Tritium will diffuse in bulk tungsten at elevated temperatures, and can be trapped in radiation-induced trap site (up to 1 at. % T/W) in tungsten [1,2]. Tritium decay into helium-3 may also play a major role in microstructuralmore » evolution (e.g. helium embrittlement) in tungsten due to relatively low helium-4 production (e.g. He/dpa ratio of 0.4-0.7 appm [3]) in tungsten. Tritium-decay helium-3 effect on tungsten is hardly understood, and its database is very limited. Two tungsten samples (99.99 at. % purity from A.L.M.T. Co., Japan) were exposed to high flux (ion flux of 1.0x1022 m-2s-1 and ion fluence of 1.0x1026 m-2) 0.5%T2/D2 plasma at two different temperatures (200, and 500°C) in Tritium Plasma Experiment (TPE) at Idaho National Laboratory. Tritium implanted samples were stored at ambient temperature in air for more than 3 years to investigate tritium decay helium-3 effect in tungsten. The tritium distributions on plasma-exposed was monitored by a tritium imaging plate technique during storage period [4]. Thermal desorption spectroscopy was performed with a ramp rate of 10°C/min up to 900°C to outgas residual deuterium and tritium but keep helium-3 in tungsten. These helium-3 implanted samples were exposed to deuterium plasma in TPE to investigate helium-3 effect on deuterium behavior in tungsten. The results show that tritium surface concentration in 200°C sample decreased to 30 %, but tritium surface concentration in 500°C sample did not alter over the 3 years storage period, indicating possible

Atmospheric helium and geomagnetic field reversals.

NASA Technical Reports Server (NTRS)

Sheldon, W. R.; Kern, J. W.

1972-01-01

The problem of the earth's helium budget is examined in the light of recent work on the interaction of the solar wind with nonmagnetic planets. It is proposed that the dominant mode of helium (He4) loss is ion pumping by the solar wind during geomagnetic field reversals, when the earth's magnetic field is very small. The interaction of the solar wind with the earth's upper atmosphere during such a period is found to involve the formation of a bow shock. The penetration altitude of the shock-heated solar plasma is calculated to be about 700 km, and ionization rates above this level are estimated for a cascade ionization (electron avalanche) process to average 10 to the 9th power ions/sq cm/sec. The calculated ionization rates and the capacity of the solar wind to remove ionized helium (He4) from the upper atmosphere during geomagnetic dipole reversals are sufficient to yield a secular equilibrium over geologic time scales. The upward transport of helium from the lower atmosphere under these conditions is found to be adequate to sustain the proposed loss rate.

The operation of the LHC accelerator complex (2/2)

ScienceCinema

Redaelli, Stefano

2018-05-23

These lectures will give an overview of what happens when the LHC is in running mode. They are aimed at students working on the LHC experiments, but all those who are curious about what happens behind the scenes of the LHC are welcomed. You will learn all you always wanted to know about the LHC, and never had the courage to ask! The only pre-requisite is a basic, college-level, knowledge of EM and of the principles that allow to steer charged beams. Topics covered will include, among others: - the description of the injector chain, from the generation of the protons, to the delivery of bunches to the LHC. - the discussion of the steps required to accelerate the beams in the LHC, to bring them into collision, and to control the luminosity at the interaction points. - the description of the monitoring tools available to the LHC operators, and an explanation of the various plots and panels that can be found on the LHC web pages

The operation of the LHC accelerator complex (1/2)

ScienceCinema

Redaelli, Stefano

2018-05-23

These lectures will give an overview of what happens when the LHC is in running mode. They are aimed at students working on the LHC experiments, but all those who are curious about what happens behind the scenes of the LHC are welcomed. You will learn all you always wanted to know about the LHC, and never had the courage to ask! The only pre-requisite is a basic, college-level, knowledge of EM and of the principles that allow to steer charged beams. Topics covered will include, among others: - the description of the injector chain, from the generation of the protons, to the delivery of bunches to the LHC. - the discussion of the steps required to accelerate the beams in the LHC, to bring them into collision, and to control the luminosity at the interaction points. - the description of the monitoring tools available to the LHC operators, and an explanation of the various plots and panels that can be found on the LHC web pages.

49 CFR 178.347-4 - Pressure relief.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank must be equipped with a pressure and vacuum relief system in accordance with § 178.345-10 and this section. (b) Type and...

49 CFR 178.347-4 - Pressure relief.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank must be equipped with a pressure and vacuum relief system in accordance with § 178.345-10 and this section. (b) Type and...

49 CFR 178.347-4 - Pressure relief.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank must be equipped with a pressure and vacuum relief system in accordance with § 178.345-10 and this section. (b) Type and...

49 CFR 178.347-4 - Pressure relief.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank must be equipped with a pressure and vacuum relief system in accordance with § 178.345-10 and this section. (b) Type and...

Realization of mechanical rotation in superfluid helium

NASA Astrophysics Data System (ADS)

Gordon, E. B.; Kulish, M. I.; Karabulin, A. V.; Matyushenko, V. I.; Dyatlova, E. V.; Gordienko, A. S.; Stepanov, M. E.

2017-09-01

The possibility of using miniaturized low-power electric motors submerged in superfluid helium for organization of rotation inside a cryostat has been investigated. It has been revealed that many of commercial micromotors can operate in liquid helium consuming low power. Turret with 5 sample holders, assembled on the base of stepper motor, has been successfully tested in experiments on the nanowire production in quantized vortices of superfluid helium. Application of the stepper motor made it possible in a single experiment to study the effect of various experimental parameters on the yield and quality of the nanowires. The promises for continuous fast rotation of the bath filled by superfluid helium by using high-speed brushless micromotor were outlined and tested. Being realized, this approach will open new possibility to study the guest particles interaction with the array of parallel linear vortices in He II.

LHC Nobel Symposium Proceedings

NASA Astrophysics Data System (ADS)

Ekelöf, Tord

2013-12-01

In the summer of 2012, a great discovery emerged at the Large Hadron Collider (LHC) at CERN in Geneva. A plethora of new precision data had already by then been collected by the ATLAS and CMS experiments at LHC, providing further extensive support for the validity of the Standard Model of particle physics. But what now appeared was the first evidence for what was not only the last unverified prediction of the Standard Model, but also perhaps the most decisive one: the prediction made already in 1964 of a unique scalar boson required by the theory of François Englert and Peter Higgs on how fundamental particles acquire mass. At that moment in 2012, it seemed particularly appropriate to start planning a gathering of world experts in particle physics to take stock of the situation and try to answer the challenging question: what next? By May 2013, when the LHC Nobel Symposium was held at the Krusenberg Mansion outside Uppsala in Sweden, the first signs of a great discovery had already turned into fully convincing experimental evidence for the existence of a scalar boson of mass about 125 GeV, having properties compatible with the 50-year-old prediction. And in October 2013, the evidence was deemed so convincing that the Swedish Royal Academy of Sciences awarded the Nobel Prize in Physics to Englert and Higgs for their pioneering work. At the same time the search at the LHC for other particles, beyond those predicted by the Standard Model, with heavier masses up to—and in some cases beyond—1 TeV, had provided no positive result. The triumph of the Standard Model seems resounding, in particular because the mass of the discovered scalar boson is such that, when identified with the Higgs boson, the Standard Model is able to provide predictions at energies as high as the Planck mass, although at the price of accepting that the vacuum would be metastable. However, even if there were some feelings of triumph, the ambience at the LHC Nobel Symposium was more one of

Volunteer Clouds and Citizen Cyberscience for LHC Physics

NASA Astrophysics Data System (ADS)

Aguado Sanchez, Carlos; Blomer, Jakob; Buncic, Predrag; Chen, Gang; Ellis, John; Garcia Quintas, David; Harutyunyan, Artem; Grey, Francois; Lombrana Gonzalez, Daniel; Marquina, Miguel; Mato, Pere; Rantala, Jarno; Schulz, Holger; Segal, Ben; Sharma, Archana; Skands, Peter; Weir, David; Wu, Jie; Wu, Wenjing; Yadav, Rohit

2011-12-01

Computing for the LHC, and for HEP more generally, is traditionally viewed as requiring specialized infrastructure and software environments, and therefore not compatible with the recent trend in "volunteer computing", where volunteers supply free processing time on ordinary PCs and laptops via standard Internet connections. In this paper, we demonstrate that with the use of virtual machine technology, at least some standard LHC computing tasks can be tackled with volunteer computing resources. Specifically, by presenting volunteer computing resources to HEP scientists as a "volunteer cloud", essentially identical to a Grid or dedicated cluster from a job submission perspective, LHC simulations can be processed effectively. This article outlines both the technical steps required for such a solution and the implications for LHC computing as well as for LHC public outreach and for participation by scientists from developing regions in LHC research.

Physics opportunities with a fixed target experiment at the LHC (AFTER@LHC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadjidakis, Cynthia; Anselmino, Mauro; Arnaldi, R.

By extracting the beam with a bent crystal or by using an internal gas target, the multi-TeV proton and lead LHC beams allow one to perform the most energetic fixed-target experiments (AFTER@LHC) and to study p+p and p+A collisions at \\sqrt{s_NN}=115 GeV and Pb+p and Pb+A collisions at \\sqrt{s_NN}=72 GeV. Such studies would address open questions in the domain of the nucleon and nucleus partonic structure at high-x, quark-gluon plasma and, by using longitudinally or transversally polarised targets, spin physics. In this paper, we discuss the physics opportunities of a fixed-target experiment at the LHC and we report on themore » possible technical implementations of a high-luminosity experiment. We finally present feasibility studies for Drell-Yan, open heavy-flavour and quarkonium production, with an emphasis on high-x and spin physics.« less

Optomechanics in a Levitated Droplet of Superfluid Helium

NASA Astrophysics Data System (ADS)

Brown, Charles; Harris, Glen; Harris, Jack

2017-04-01

A critical issue common to all optomechanical systems is dissipative coupling to the environment, which limits the system's quantum coherence. Superfluid helium's extremely low optical and mechanical dissipation, as well as its high thermal conductivity and its ability cool itself via evaporation, makes the mostly uncharted territory of superfluid optomechanics an exciting avenue for exploring quantum effects in macroscopic objects. I will describe ongoing work that aims to exploit the unique properties of superfluid helium by constructing an optomechanical system consisting of a magnetically levitated droplet of superfluid helium., The optical whispering gallery modes (WGMs) of the droplet, as well as the mechanical oscillations of its surface, should offer exceptionally low dissipation, and should couple to each other via the usual optomechanical interactions. I will present recent progress towards this goal, and also discuss the background for this work, which includes prior demonstrations of magnetic levitation of superfluid helium, high finesse WGMs in liquid drops, and the self-cooling of helium drops in vacuum.

Simplified Helium Refrigerator Cycle Analysis Using the `Carnot Step'

DOE Office of Scientific and Technical Information (OSTI.GOV)

P. Knudsen; V. Ganni

2006-05-01

An analysis of the Claude form of an idealized helium liquefier for the minimum input work reveals the ''Carnot Step'' for helium refrigerator cycles. As the ''Carnot Step'' for a multi-stage polytropic compression process consists of equal pressure ratio stages; similarly for an idealized helium liquefier the ''Carnot Step'' consists of equal temperature ratio stages for a given number of expansion stages. This paper presents the analytical basis and some useful equations for the preliminary examination of existing and new Claude helium refrigeration cycles.

Helium segregation on surfaces of plasma-exposed tungsten

DOE PAGES

Maroudas, Dimitrios; Blondel, Sophie; Hu, Lin; ...

2016-01-21

Here we report a hierarchical multi-scale modeling study of implanted helium segregation on surfaces of tungsten, considered as a plasma facing component in nuclear fusion reactors. We employ a hierarchy of atomic-scale simulations based on a reliable interatomic interaction potential, including molecular-statics simulations to understand the origin of helium surface segregation, targeted molecular-dynamics (MD) simulations of near-surface cluster reactions, and large-scale MD simulations of implanted helium evolution in plasma-exposed tungsten. We find that small, mobile He-n (1 <= n <= 7) clusters in the near-surface region are attracted to the surface due to an elastic interaction force that provides themore » thermodynamic driving force for surface segregation. Elastic interaction force induces drift fluxes of these mobile Hen clusters, which increase substantially as the migrating clusters approach the surface, facilitating helium segregation on the surface. Moreover, the clusters' drift toward the surface enables cluster reactions, most importantly trap mutation, in the near-surface region at rates much higher than in the bulk material. Moreover, these near-surface cluster dynamics have significant effects on the surface morphology, near-surface defect structures, and the amount of helium retained in the material upon plasma exposure. We integrate the findings of such atomic-scale simulations into a properly parameterized and validated spatially dependent, continuum-scale reaction-diffusion cluster dynamics model, capable of predicting implanted helium evolution, surface segregation, and its near-surface effects in tungsten. This cluster-dynamics model sets the stage for development of fully atomistically informed coarse-grained models for computationally efficient simulation predictions of helium surface segregation, as well as helium retention and surface morphological evolution, toward optimal design of plasma facing components.« less

Helium segregation on surfaces of plasma-exposed tungsten

NASA Astrophysics Data System (ADS)

Maroudas, Dimitrios; Blondel, Sophie; Hu, Lin; Hammond, Karl D.; Wirth, Brian D.

2016-02-01

We report a hierarchical multi-scale modeling study of implanted helium segregation on surfaces of tungsten, considered as a plasma facing component in nuclear fusion reactors. We employ a hierarchy of atomic-scale simulations based on a reliable interatomic interaction potential, including molecular-statics simulations to understand the origin of helium surface segregation, targeted molecular-dynamics (MD) simulations of near-surface cluster reactions, and large-scale MD simulations of implanted helium evolution in plasma-exposed tungsten. We find that small, mobile He n (1  ⩽  n  ⩽  7) clusters in the near-surface region are attracted to the surface due to an elastic interaction force that provides the thermodynamic driving force for surface segregation. This elastic interaction force induces drift fluxes of these mobile He n clusters, which increase substantially as the migrating clusters approach the surface, facilitating helium segregation on the surface. Moreover, the clusters’ drift toward the surface enables cluster reactions, most importantly trap mutation, in the near-surface region at rates much higher than in the bulk material. These near-surface cluster dynamics have significant effects on the surface morphology, near-surface defect structures, and the amount of helium retained in the material upon plasma exposure. We integrate the findings of such atomic-scale simulations into a properly parameterized and validated spatially dependent, continuum-scale reaction-diffusion cluster dynamics model, capable of predicting implanted helium evolution, surface segregation, and its near-surface effects in tungsten. This cluster-dynamics model sets the stage for development of fully atomistically informed coarse-grained models for computationally efficient simulation predictions of helium surface segregation, as well as helium retention and surface morphological evolution, toward optimal design of plasma facing components.

Le LHC, un tunnel cosmique

ScienceCinema

None

2017-12-09

Et si la lumière au bout du tunnel du LHC était cosmique ? En d’autres termes, qu’est-ce que le LHC peut nous apporter dans la connaissance de l’Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l’univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l’Univers ? La matière noire est-elle détectable au LHC ? L’énergie noire ? Pourquoi l’antimatière accumulée au CERN est-elle si rare dans l’Univers ? Et si le CERN a bâti sa réputation sur l’exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l’évolution cosmique ? Depuis une trentaine d’années, notre compréhension de l’univers dans ses plus grandes dimensions et l’appréhension de son comportement aux plus petites distances sont intimement liées : en quoi le LHC va-t-il tester expérimentalement cette vision unifiée ? Tout public, entrée libre / Réservations au +41 (0)22 767 76 76

Effectiveness of Property Tax Relief in Oregon.

ERIC Educational Resources Information Center

Hartman, William T.; Hwang, C. S.

This study examines the effects of the 1979 Oregon Property Tax Relief Plan on 1980-81 school district budget decisions by comparing the available tax relief, the school expenditures, and the tax levies in the state for the years 1975-81. The history of direct and indirect property tax relief in Oregon is sketched for the years prior to 1979; the…

Hydrogen gas relief valve

DOEpatents

Whittlesey, Curtis C.

1985-01-01

An improved battery stack design for an electrochemical system having at least one cell from which a gas is generated and an electrolyte in communication with the cell is described. The improved battery stack design features means for defining a substantially closed compartment for containing the battery cells and at least a portion of the electrolyte for the system, and means in association with the compartment means for selectively venting gas from the interior of the compartment means in response to the level of the electrolyte within the compartment means. The venting means includes a relief valve having a float member which is actuated in response to the level of the electrolyte within the compartment means. This float member is adapted to close the relief valve when the level of the electrolyte is above a predetermined level and open the relief valve when the level of electrolyte is below this predetermined level.

Nanopore fabrication and characterization by helium ion microscopy

NASA Astrophysics Data System (ADS)

Emmrich, D.; Beyer, A.; Nadzeyka, A.; Bauerdick, S.; Meyer, J. C.; Kotakoski, J.; Gölzhäuser, A.

2016-04-01

The Helium Ion Microscope (HIM) has the capability to image small features with a resolution down to 0.35 nm due to its highly focused gas field ionization source and its small beam-sample interaction volume. In this work, the focused helium ion beam of a HIM is utilized to create nanopores with diameters down to 1.3 nm. It will be demonstrated that nanopores can be milled into silicon nitride, carbon nanomembranes, and graphene with well-defined aspect ratio. To image and characterize the produced nanopores, helium ion microscopy and high resolution scanning transmission electron microscopy were used. The analysis of the nanopores' growth behavior allows inferring on the profile of the helium ion beam.

Helium tables.

NASA Technical Reports Server (NTRS)

Havill, Clinton H

1928-01-01

These tables are intended to provide a standard method and to facilitate the calculation of the quantity of "Standard Helium" in high pressure containers. The research data and the formulas used in the preparation of the tables were furnished by the Research Laboratory of Physical Chemistry, of the Massachusetts Institute of Technology.

Relief Presentation on US National Park Service Maps

NASA Astrophysics Data System (ADS)

Patterson, Tom

2018-05-01

This paper examines the evolution of relief presentations on maps developed by Harpers Ferry Center, the media service center of the US National Park Service (NPS). Harpers Ferry Center produces the maps used by park visitors. I will discuss five park maps, each with a distinctive relief style and mode of production. They appear in rough chronological order of their development. Recent relief presentations are generally more detailed, colorful, and realistic than those from earlier years. Changing technology is largely responsible for the different relief styles found on park maps. Some relief treatments today were not possible, or imaginable, in 1977 when the NPS established the brochure program in its modern phase. Landscape heterogeneity is another factor behind the development of different relief styles. With over 400 park sites ranging from the glacial mountains of Alaska to the rolling piedmont of Virginia, a one-style-fits-all approach cannot adequately depict all landscapes. NPS maps serve some 300 million park visitors each year. Our ongoing effort to make understandable maps for this diverse audience has further spurred experiments in relief presentation.

Neutral helium beam probe

NASA Astrophysics Data System (ADS)

Karim, Rezwanul

1999-10-01

This article discusses the development of a code where diagnostic neutral helium beam can be used as a probe. The code solves numerically the evolution of the population densities of helium atoms at their several different energy levels as the beam propagates through the plasma. The collisional radiative model has been utilized in this numerical calculation. The spatial dependence of the metastable states of neutral helium atom, as obtained in this numerical analysis, offers a possible diagnostic tool for tokamak plasma. The spatial evolution for several hypothetical plasma conditions was tested. Simulation routines were also run with the plasma parameters (density and temperature profiles) similar to a shot in the Princeton beta experiment modified (PBX-M) tokamak and a shot in Tokamak Fusion Test Reactor tokamak. A comparison between the simulation result and the experimentally obtained data (for each of these two shots) is presented. A good correlation in such comparisons for a number of such shots can establish the accurateness and usefulness of this probe. The result can possibly be extended for other plasma machines and for various plasma conditions in those machines.

Abort Gap Cleaning for LHC Run 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uythoven, Jan; Boccardi, Andrea; Bravin, Enrico

2014-07-01

To minimize the beam losses at the moment of an LHC beam dump the 3 μs long abort gap should contain as few particles as possible. Its population can be minimised by abort gap cleaning using the LHC transverse damper system. The LHC Run 1 experience is briefly recalled; changes foreseen for the LHC Run 2 are presented. They include improvements in the observation of the abort gap population and the mechanism to decide if cleaning is required, changes to the hardware of the transverse dampers to reduce the detrimental effect on the luminosity lifetime and proposed changes to themore » applied cleaning algorithms.« less

Iraq’s Debt Relief: Procedure and Potential Implications for International Debt Relief

DTIC Science & Technology

2009-01-26

countries use different interest rates and levy different penalties for Iraq’s payment arrears . Hence, the debt owed to each creditor can grow at...REPORT DATE 26 JAN 2009 2. REPORT TYPE 3. DATES COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Iraq’s Debt Relief: Procedure and...Potential Implications for International Debt Relief 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e

High Luminosity LHC: Challenges and plans

DOE PAGES

Arduini, G.; Barranco, J.; Bertarelli, A.; ...

2016-12-28

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will undergo a major upgrade in the 2020s. This will increase its rate of collisions by a factor of five beyond the original design value and the integrated luminosity by a factor ten. The new configuration, known as High Luminosity LHC (HL-LHC), willmore » rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11–12 T superconducting magnets, including Nb 3Sn-based magnets never used in accelerators before, compact superconducting cavities for longitudinal beam rotation, new technology and physical processes for beam collimation. As a result, the dynamics of the HL-LHC beams will be also particularly challenging and this aspect is the main focus of this paper.« less

The scattering of low energy positrons by helium

NASA Technical Reports Server (NTRS)

Humberston, J. W.

1973-01-01

Kohn's variational method is used to calculate the positron-helium scattering length and low energy S-wave phase shifts for a quite realistic Hylleraas type of helium function containing an electron-electron correlation term. The zero energy wavefunction is used to calculate the value of the annihilation rate parameter Z sub eff. All the results are significantly different from those for Drachman's helium model B, but are in better agreement with the available experimental data.

The HL-LHC Accelerator Physics Challenges

NASA Astrophysics Data System (ADS)

Fartoukh, S.; Zimmermann, F.

The conceptual baseline of the HL-LHC project is reviewed, putting into perspective the main beam physics challenges of this new collider in comparison with the existing LHC, and the series of solutions and possible mitigation measures presently envisaged.

The Role of Helium Metastable States in Radio-Frequency Helium-Oxygen Atmospheric Pressure Plasma Jets: Measurement and Numerical Simulation

NASA Astrophysics Data System (ADS)

Niemi, Kari; Waskoenig, Jochen; Sadeghi, Nader; Gans, Timo; O'Connell, Deborah

2011-10-01

Absolute densities of metastable He atoms were measured line-of sight integrated along the plasma channel of a capacitively-coupled radio-frequency driven atmospheric pressure plasma jet operated in helium oxygen mixtures by tunable diode-laser absorption spectroscopy. Dependencies of the He metastable density with oxygen admixtures up to 1 percent were investigated. Results are compared to a 1-d numerical simulation, which includes a semi-kinetical treatment of the electron dynamics and the complex plasma chemistry (20 species, 184 reactions), and very good agreement is found. The main formation mechanisms for the helium metastables are identified and analyzed, including their pronounced spatio-temporal dynamics. Penning ionization through helium metastables is found to be significant for plasma sustainment, while it is revealed that helium metastables are not an important energy carrying species into the jet effluent and therefore will not play a direct role in remote surface treatments.

Anatomy of the inert two-Higgs-doublet model in the light of the LHC and non-LHC dark matter searches

NASA Astrophysics Data System (ADS)

Belyaev, Alexander; Cacciapaglia, Giacomo; Ivanov, Igor P.; Rojas-Abatte, Felipe; Thomas, Marc

2018-02-01

The inert two-Higgs-doublet model (i2HDM) is a theoretically well-motivated example of a minimal consistent dark matter (DM) model which provides monojet, mono-Z , mono-Higgs, and vector-boson-fusion +ETmiss signatures at the LHC, complemented by signals in direct and indirect DM search experiments. In this paper we have performed a detailed analysis of the constraints in the full five-dimensional parameter space of the i2HDM, coming from perturbativity, unitarity, electroweak precision data, Higgs data from the LHC, DM relic density, direct/indirect DM detection, and LHC monojet analysis, as well as implications of experimental LHC studies on disappearing charged tracks relevant to a high DM mass region. We demonstrate the complementarity of the above constraints and present projections for future LHC data and direct DM detection experiments to probe further i2HDM parameter space. The model is implemented into the CalcHEP and micrOMEGAs packages, which are publicly available at the HEPMDB database, and it is ready for a further exploration in the context of the LHC, relic density, and DM direct detection.

19 CFR 210.52 - Motions for temporary relief.

Code of Federal Regulations, 2010 CFR

2010-04-01

....52 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION INVESTIGATIONS OF UNFAIR PRACTICES IN IMPORT TRADE ADJUDICATION AND ENFORCEMENT Temporary Relief § 210.52 Motions for temporary relief... issuance of temporary relief, the Commission will be guided by practice under Rule 65 of the Federal Rules...

46 CFR 154.806 - Capacity of pressure relief valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Capacity of pressure relief valves. 154.806 Section 154... Equipment Cargo Vent Systems § 154.806 Capacity of pressure relief valves. Pressure relief valves for each cargo tank must have a combined relief capacity, including the effects of back pressure from vent piping...

Pulsed helium ionization detection system

DOEpatents

Ramsey, R.S.; Todd, R.A.

1985-04-09

A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

Pulsed helium ionization detection system

DOEpatents

Ramsey, Roswitha S.; Todd, Richard A.

1987-01-01

A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

Hybrid Circuit QED with Electrons on Helium

NASA Astrophysics Data System (ADS)

Yang, Ge

Electrons on helium (eHe) is a 2-dimensional system that forms naturally at the interface between superfluid helium and vacuum. It has the highest measured electron mobility, and long predicted spin coherence time. In this talk, we will first review various quantum computer architecture proposals that take advantage of these exceptional properties. In particular, we describe how electrons on helium can be combined with superconducting microwave circuits to take advantage of the recent progress in the field of circuit quantum electrodynamics (cQED). We will then demonstrate how to reliably trap electrons on these devices hours at a time, at millikelvin temperatures inside a dilution refrigerator. The coupling between the electrons and the microwave resonator exceeds 1 MHz, and can be reproduced from the design geometry using our numerical simulation. Finally, we will present our progress on isolating individual electrons in such circuits, to build single-electron quantum dots with electrons on helium.

Formation of the lunar helium corona and atmosphere

NASA Technical Reports Server (NTRS)

Hodges, R. R., Jr.

1977-01-01

Helium is one of the dominant gases of the lunar atmosphere. Its presence is easily identified in data from the mass spectrometer at the Apollo 17 landing site. The major part of these data was obtained in lunar nighttime, where helium concentration reaches the maximum of its diurnal cyclic variation. The large night to day concentration ratio agrees with the basic theory of exospheric lateral transport reported by Hodges and Johnson (1968). A reasonable fraction of atmospheric helium atoms has a velocity in excess of the gravitational escape velocity. The result is a short average lifetime and a tenuous helium atmosphere. A description is presented of an investigation which shows that the atmosphere of the moon has two distinct components including low energy atoms, which are gravitationally bound in trajectories that intersect the lunar surface, and higher energy atoms, which are trapped in satellite orbits. The total helium abundance in the lunar corona is shown to be about 1.3 times 10 to the 30th power atoms.

Helium vs. Proton Induced Displacement Damage in Electronic Materials

NASA Technical Reports Server (NTRS)

Ringo, Sawnese; Barghouty, A. F.

2010-01-01

In this project, the specific effects of displacement damage due to the passage of protons and helium nuclei on some typical electronic materials will be evaluated and contrasted. As the electronic material absorbs the energetic proton and helium momentum, degradation of performance occurs, eventually leading to overall failure. Helium nuclei traveling at the same speed as protons are expected to impart more to the material displacement damage; due to the larger mass, and thus momentum, of helium nuclei compared to protons. Damage due to displacement of atoms in their crystalline structure can change the physical properties and hence performance of the electronic materials.

Considerations on Energy Frontier Colliders after LHC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiltsev, Vladimir

2016-11-15

Since 1960’s, particle colliders have been in the forefront of particle physics, 29 total have been built and operated, 7 are in operation now. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). The future of the world-wide HEP community critically depends on the feasibility of possible post-LHC colliders. The concept of the feasibility is complex and includes at least three factors: feasibility of energy, feasibility of luminosity and feasibility of cost. Here wemore » overview all current options for post-LHC colliders from such perspective (ILC, CLIC, Muon Collider, plasma colliders, CEPC, FCC, HE-LHC) and discuss major challenges and accelerator R&D required to demonstrate feasibility of an energy frontier accelerator facility following the LHC. We conclude by taking a look into ultimate energy reach accelerators based on plasmas and crystals, and discussion on the perspectives for the far future of the accelerator-based particle physics. This paper largely follows previous study [1] and the presenta ion given at the ICHEP’2016 conference in Chicago [2].« less

Experiences in disaster-related mental health relief work: An exploratory model for the interprofessional training of psychological relief workers.

PubMed

Ren, ZhengJia; Wang, HongTao; Zhang, Wei

2017-01-01

The purpose of this study was to begin to generate an exploratory model of the disaster-related mental health education process associated with the training experiences of psychological relief workers active during the Sichuan earthquake in China. The data consisted of semi-structured interviews with 20 psychological relief workers from four different professions (social workers, psychiatric nurses, psychiatrists, and counsellors) regarding their experiences in training and ideas for improvement. The model explains the need to use a people-centred community interprofessional education approach, which focuses on role-modelling of the trainer, caring for relief workers, paying attention to the needs of the trainee, and building systematic interprofessional education strategies. The proposed model identifies areas for the comprehensive training of relief workers and aims to address the importance of people-centred mental health service provisions, ensure intentional and strategic training of relief workers using interprofessional concepts and strategies, and use culturally attuned and community-informed strategies in mental health training practices.

30 CFR 204.203 - What is the other relief option?

Code of Federal Regulations, 2010 CFR

2010-07-01

... MANAGEMENT ALTERNATIVES FOR MARGINAL PROPERTIES Accounting and Auditing Relief § 204.203 What is the other relief option? (a) Under this relief option, you may request any type of accounting and auditing relief...

Diffusion of radiogenic helium in natural uranium oxides

NASA Astrophysics Data System (ADS)

Roudil, Danièle; Bonhoure, Jessica; Pik, Raphaël; Cuney, Michel; Jégou, Christophe; Gauthier-Lafaye, F.

2008-08-01

The issue of nuclear waste management - and especially spent fuel disposal - demands further research on the long-term behavior of helium and its impact on physical changes in UO 2 and (U,Pu)O 2 matrices subjected to self-irradiation. Helium produced by radioactive decay of the actinides concentrates in the grains or is trapped at the grain boundaries. Various scenarios can be considered, and can have a significant effect on the radionuclide source terms that will be accessible to water after the canisters have been breached. Helium production and matrix damage is generally simulated by external irradiation or with actinide-doped materials. A natural uranium oxide sample was studied to acquire data on the behavior of radiogenic helium and its diffusion under self-irradiation in spent fuel. The sample from the Pen Ar Ran deposit in the Vendée region of France dated at 320 ± 9 million of years was selected for its simple geological history, making it a suitable natural analog of spent fuel under repository conditions during the initial period in a closed system not subject to mass transfer with the surrounding environment. Helium outgassing measured by mass spectrometry to determine the He diffusion coefficients through the ore shows that: (i) a maximum of 5% (2.1% on average) of the helium produced during the last 320 Ma in this natural analog was conserved, (ii) about 33% of the residual helium is occluded in the matrix and vacancy defects (about 10 -5 mol g -1) and 67% in bubbles that were analyzed by HRTEM. A similar distribution has been observed in spent fuel and in (U 0.9,Pu 0.1)O 2. The results obtained for the natural Pen Ar Ran sample can be applied by analogy to spent fuel, especially in terms of the apparent solubility limit and the formation, characteristics and behavior of the helium bubbles.

7 CFR 636.20 - Equitable relief.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Equitable relief. 636.20 Section 636.20 Agriculture Regulations of the Department of Agriculture (Continued) NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE LONG TERM CONTRACTING WILDLIFE HABITAT INCENTIVES PROGRAM § 636.20 Equitable relief. (a) If a...

7 CFR 636.20 - Equitable relief.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 6 2011-01-01 2011-01-01 false Equitable relief. 636.20 Section 636.20 Agriculture Regulations of the Department of Agriculture (Continued) NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE LONG TERM CONTRACTING WILDLIFE HABITAT INCENTIVE PROGRAM § 636.20 Equitable relief. (a) If a...

7 CFR 636.20 - Equitable relief.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 6 2014-01-01 2014-01-01 false Equitable relief. 636.20 Section 636.20 Agriculture Regulations of the Department of Agriculture (Continued) NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE LONG TERM CONTRACTING WILDLIFE HABITAT INCENTIVE PROGRAM § 636.20 Equitable relief. (a) If a...

7 CFR 636.20 - Equitable relief.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 6 2012-01-01 2012-01-01 false Equitable relief. 636.20 Section 636.20 Agriculture Regulations of the Department of Agriculture (Continued) NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE LONG TERM CONTRACTING WILDLIFE HABITAT INCENTIVE PROGRAM § 636.20 Equitable relief. (a) If a...

7 CFR 636.20 - Equitable relief.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 6 2013-01-01 2013-01-01 false Equitable relief. 636.20 Section 636.20 Agriculture Regulations of the Department of Agriculture (Continued) NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE LONG TERM CONTRACTING WILDLIFE HABITAT INCENTIVE PROGRAM § 636.20 Equitable relief. (a) If a...

Aspirator increases relief valve poppet stroke

NASA Technical Reports Server (NTRS)

Biddle, M. E.

1967-01-01

Addition of an aspirator to a relief valve increases the valve poppet stroke under dynamic flow conditions. The aspirator allows poppet inlet dynamic forces to overcome relief valve spring force. It reduces the fluid pressure in the skirt cavity by providing a low pressure sense probe.

Electronic Spectroscopy of Phthalocyanine and Porphyrin Derivatives in Superfluid Helium Nanodroplets.

PubMed

Slenczka, Alkwin

2017-07-25

Phthalocyanine and porphyrin were among the first organic compounds investigated by means of electronic spectroscopy in superfluid helium nanodroplets. Superfluid helium nanodroplets serve as a very gentle host system for preparing cold and isolated molecules. The uniqueness of helium nanodroplets is with respect to the superfluid phase which warrants the vanishing viscosity and, thus, minimal perturbation of the dopant species at a temperature as low as 0.37 K. These are ideal conditions for the study of molecular spectra in order to analyze structures as well as dynamic processes. Besides the investigation of the dopant species itself, molecular spectroscopy in helium droplets provides information on the helium droplet and in particular on microsolvation. This article, as part of a special issue on phthalocyanines and porphyrins, reviews electronic spectroscopy of phthalocyanine and porphyrin compounds in superfluid helium nanodroplets. In addition to the wide variety of medical as well as technical and synthetical aspects, this article discusses electronic spectroscopy of phthalocyanines and porphyrins in helium droplets in order to learn about both the dopant and the helium environment.

Speech intelligibility at high helium-oxygen pressures.

PubMed

Rothman, H B; Gelfand, R; Hollien, H; Lambertsen, C J

1980-12-01

Word-list intelligibility scores of unprocessed speech (mean of 4 subjects) were recorded in helium-oxygen atmospheres at stable pressures equivalent to 1600, 1400, 1200, 1000, 860, 690, 560, 392, and 200 fsw daring Predictive Studies IV-1975 by wide-bandwidth condenser microphones (frequency responses not degraded by increased gas density). Intelligibility scores were substantially lower in helium-oxygen a 200 fsw than in air at l ATA, but there was little difference between 200 fsw and 1600 fsw. A previously documented prominent decrease in intelligibility of speech between 200 or 600 fsw because of helium and pressure was probably due to degradation of microphone frequency response by high gas density.

Using Uncertainty Principle to Find the Ground-State Energy of the Helium and a Helium-like Hookean Atom

ERIC Educational Resources Information Center

Harbola, Varun

2011-01-01

In this paper, we accurately estimate the ground-state energy and the atomic radius of the helium atom and a helium-like Hookean atom by employing the uncertainty principle in conjunction with the variational approach. We show that with the use of the uncertainty principle, electrons are found to be spread over a radial region, giving an electron…

Damage-Free Relief-Valve Disassembly

NASA Technical Reports Server (NTRS)

Haselmaier, H.

1986-01-01

Tool safely disassembles relief valves without damage to sensitive parts. Relief-valve disassembly tool used to extract valve nozzle from its housing. Holding device on tool grops nozzle. When user strikes hammer against impact disk, holding device pulls nozzle from press fit. Previously, nozzle dislodged by striking spindle above it, but practice often damaged retaining screw. New tool removes nozzle directly. With minor modifications, tool adapted to valves from different manufacturers.

Crisis Communication Practices at an International Relief Agency

ERIC Educational Resources Information Center

Genova, Gina L.

2006-01-01

When a disaster strikes, the affected population relies upon the swift response and aid rendered by relief organizations such as the California-based Direct Relief International. Since 1948, Direct Relief's mission has been to provide essential material resources to locally run health programs in areas affected by natural disasters, wars, and…

19 CFR 210.68 - Complainant's temporary relief bond.

Code of Federal Regulations, 2010 CFR

2010-04-01

... bond is being posted, the amount of the bond, the effective date and duration of the bond (as... 19 Customs Duties 3 2010-04-01 2010-04-01 false Complainant's temporary relief bond. 210.68... relief bond. (a) In every investigation under this part involving a motion for temporary relief, the...

Development of an Agent-based Model to Analyze Contemporary Helium Markets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riddle, Matthew E.; Uckun, Canan; Conzelmann, Guenter

Although U.S. helium demand has remained relatively flat since 2009, exports of helium have increased significantly since then, driven primarily by demand for electronic and semiconductor manufacturing in Asia. In the midst of this global demand shift, the Helium Act dictates a new procedure for pricing and distributing the gas through a reserve that historically functioned as a loose “oligarchy.” The new procedure requires prices to be determined by the open market through auctions and a survey of market prices, as opposed to increasing prices according to the consumer price index. Response to these changes has caused temporary shortages, pricemore » increases, and a significant increase in the development of the helium extraction technologies used to produce helium from formerly marginal sources. Technologies are being developed and refined to extract helium from formerly low-yielding natural gas fields containing much lower amounts of helium than the previously considered economic threshold of 0.3%. Combining these transformative policies with the potential for new and significant global supplies from Qatar, Algeria, and Russia could lead to new and unforeseen market behaviors and reactions from global helium markets. The objective of the project is to analyze the global helium markets.« less

Design and Manufacturing of the Kstar Tokamak Helium Refrigeration System

NASA Astrophysics Data System (ADS)

Dauguet, P.; Briend, P.; Abe, I.; Fauve, E.; Bernhardt, J. M.; Andrieu, F.; Beauvisage, J.

2008-03-01

The KSTAR (Korean Superconducting Tokamak Advanced Research) project makes intensive use of superconducting (SC) magnets operated at 4.4 K. The cold components of KSTAR require a forced flow of supercritical helium for magnets and structure, boiling liquid helium for current leads, and gaseous helium for thermal shields. A helium refrigeration system has been custom-designed for this project. The purpose of this paper is to give a brief overview of the proposed cryogenic system. The specified thermal loads for the different operating modes are presented. This specification results in the definition of a design mode for the refrigerator. The design and construction of the resulting 9 kW at 4.5-K Helium Refrigeration System (HSR) are presented.

Development of a Novel Method for the Exploration of the Thermal Response of Superfluid Helium Cooled Superconducting Cables to Pulse Heat Loads

NASA Astrophysics Data System (ADS)

Winkler, T.; Koettig, T.; van Weelderen, R.; Bremer, J.; ter Brake, H. J. M.

Management of transient heat deposition in superconducting magnets and its extraction from the aforementioned is becoming increasingly important to bring high energy particle accelerator performance to higher beam energies and intensities. Precise knowledge of transient heat deposition phenomena in the magnet cables will permit to push the operation of these magnets as close as possible to their current sharing limit, without unduly provoking magnet quenches. With the prospect of operating the Large Hadron Collider at CERN at higher beam energies and intensities an investigation into the response to transient heat loads of LHC magnets, operating in pressurized superfluid helium, is being performed. The more frequently used approach mimics the cable geometry by resistive wires and uses Joule-heating to deposit energy. Instead, to approximate as closely as possible the real magnet conditions, a novel method for depositing heat in cable stacks made out of superconducting magnet-cables has been developed. The goal is to measure the temperature difference as a function of time between the cable stack and the superfluid helium bath depending on heat load and heat pulse length. The heat generation in the superconducting cable and precise measurement of small temperature differences are major challenges. The functional principle and experimental set-up are presented together with proof of principle measurements.

Education in Helium Refrigeration

NASA Astrophysics Data System (ADS)

Gistau Baguer, G. M.

2004-06-01

On the one hand, at the end of the time I was active in helium refrigeration, I noticed that cryogenics was stepping into places where it was not yet used. For example, a conventional accelerator, operating at room temperature, was to be upgraded to reach higher particle energy. On the other hand, I was a little bit worried to let what I had so passionately learned during these years to be lost. Retirement made time available, and I came gradually to the idea to teach about what was my basic job. I thought also about other kinds of people who could be interested in such lessons: operators of refrigerators or liquefiers who, often by lack of time, did not get a proper introduction to their job when they started, young engineers who begin to work in cryogenics… and so on. Consequently, I have assembled a series of lessons about helium refrigeration. As the audiences have different levels of knowledge in the field of cryogenics, I looked for a way of teaching that is acceptable for all of them. The course is split into theory of heat exchangers, refrigeration cycles, technology and operation of main components, process control, and helium purity.

Coupling of the coronal helium abundance to the solar wind

NASA Technical Reports Server (NTRS)

Hansteen, Viggo H.; Leer, Egil; Holzer, Thomas E.

1994-01-01

Models of the transition region-corona-solar wind system are investigated in order to find the coronal helium abundance and to study the role played by coronal helium in controlling the solar wind proton flux. The thermal force on alpha-particles in the transition region sets the flow of helium into the corona. The frictional coupling between alpha-particles and protons and/or the electric polarization field determines the proton flux in the solar wind as well as the fate of the coronal helium content. The models are constructed by solving the time-dependent population and momentum equations for all species of hydrogen and helium in an atmosphere with a given temperature profile. Several temperature profiles are considered in order to very the roles of frictional coupling and electric polarization field in the solar wind, and the thermal force in the transition region. Steady-state solutions are found for coronae with a hydrogen flux at 1 AU of 1.0 x 10(exp 9)/cm(exp 2)/sec or larger. For coronae with lower hydrogen fluxes, the helium flux into the corona is larger than the flux 'pulled out' by the solar wind protons, and solutions with increasing coronal helium content are found. The timescale for forming a helium-filled corona, that may allow for a steady outflow, is long compared to the mixing time for the corona.

Theory of Positron Annihilation in Helium-Filled Bubbles in Plutonium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sterne, P A; Pask, J E

2003-02-13

Positron annihilation lifetime spectroscopy is a sensitive probe of vacancies and voids in materials. This non-destructive measurement technique can identify the presence of specific defects in materials at the part-per-million level. Recent experiments by Asoka-Kumar et al. have identified two lifetime components in aged plutonium samples--a dominant lifetime component of around 182 ps and a longer lifetime component of around 350-400ps. This second component appears to increase with the age of the sample, and accounts for only about 5 percent of the total intensity in 35 year-old plutonium samples. First-principles calculations of positron lifetimes are now used extensively to guidemore » the interpretation of positron lifetime data. At Livermore, we have developed a first-principles finite-element-based method for calculating positron lifetimes for defects in metals. This method is capable of treating system cell sizes of several thousand atoms, allowing us to model defects in plutonium ranging in size from a mono-vacancy to helium-filled bubbles of over 1 nm in diameter. In order to identify the defects that account for the observed lifetime values, we have performed positron lifetime calculations for a set of vacancies, vacancy clusters, and helium-filled vacancy clusters in delta-plutonium. The calculations produced values of 143ps for defect-free delta-Pu and 255ps for a mono-vacancy in Pu, both of which are inconsistent with the dominant experimental lifetime component of 182ps. Larger vacancy clusters have even longer lifetimes. The observed positron lifetime is significantly shorter than the calculated lifetimes for mono-vacancies and larger vacancy clusters, indicating that open vacancy clusters are not the dominant defect in the aged plutonium samples. When helium atoms are introduced into the vacancy cluster, the positron lifetime is reduced due to the increased density of electrons available for annihilation. For a mono-vacancy in Pu containing one

Supersymmetry Breaking, Gauge Mediation, and the LHC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shih, David

2015-04-14

Gauge mediated SUSY breaking (GMSB) is a promising class of supersymmetric models that automatically satisfies the precision constraints. Prior work of Meade, Seiberg and Shih in 2008 established the full, model-independent parameter space of GMSB, which they called "General Gauge Mediation" (GGM). During the first half of 2010-2015, Shih and his collaborators thoroughly explored the parameter space of GGM and established many well-motivated benchmark models for use by the experimentalists at the LHC. Through their work, the current constraints on GGM from LEP, the Tevatron and the LHC were fully elucidated, together with the possible collider signatures of GMSB atmore » the LHC. This ensured that the full discovery potential for GGM could be completely realized at the LHC.« less

Run II of the LHC: The Accelerator Science

NASA Astrophysics Data System (ADS)

Redaelli, Stefano

2015-04-01

In 2015 the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) starts its Run II operation. After the successful Run I at 3.5 TeV and 4 TeV in the 2010-2013 period, a first long shutdown (LS1) was mainly dedicated to the consolidation of the LHC magnet interconnections, to allow the LHC to operate at its design beam energy of 7 TeV. Other key accelerator systems have also been improved to optimize the performance reach at higher beam energies. After a review of the LS1 activities, the status of the LHC start-up progress is reported, addressing in particular the status of the LHC hardware commissioning and of the training campaign of superconducting magnets that will determine the operation beam energy in 2015. Then, the plans for the Run II operation are reviewed in detail, covering choice of initial machine parameters and strategy to improve the Run II performance. Future prospects of the LHC and its upgrade plans are also presented.

Will there be energy frontier colliders after LHC?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiltsev, Vladimir

2016-09-15

High energy particle colliders have been in the forefront of particle physics for more than three decades. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). The future of the world-wide HEP community critically depends on the feasibility of possible post-LHC colliders. The concept of the feasibility is complex and includes at least three factors: feasibility of energy, feasibility of luminosity and feasibility of cost. Here we overview all current options for post-LHC collidersmore » from such perspective (ILC, CLIC, Muon Collider, plasma colliders, CEPC, FCC, HE-LHC) and discuss major challenges and accelerator R&D required to demonstrate feasibility of an energy frontier accelerator facility following the LHC. We conclude by taking a look into ultimate energy reach accelerators based on plasmas and crystals, and discussion on the perspectives for the far future of the accelerator-based particle physics.« less

Limited Quantum Helium Transportation through Nano-channels by Quantum Fluctuation

PubMed Central

Ohba, Tomonori

2016-01-01

Helium at low temperatures has unique quantum properties such as superfluidity, which causes it to behave differently from a classical fluid. Despite our deep understanding of quantum mechanics, there are many open questions concerning the properties of quantum fluids in nanoscale systems. Herein, the quantum behavior of helium transportation through one-dimensional nanopores was evaluated by measuring the adsorption of quantum helium in the nanopores of single-walled carbon nanohorns and AlPO4-5 at 2–5 K. Quantum helium was transported unimpeded through nanopores larger than 0.7 nm in diameter, whereas quantum helium transportation was significantly restricted through 0.4-nm and 0.6-nm nanopores. Conversely, nitrogen molecules diffused through the 0.4-nm nanopores at 77 K. Therefore, quantum helium behaved as a fluid comprising atoms larger than 0.4–0.6 nm. This phenomenon was remarkable, considering that helium is the smallest existing element with a (classical) size of approximately 0.27 nm. This finding revealed the presence of significant quantum fluctuations. Quantum fluctuation determined the behaviors of quantum flux and is essential to understanding unique quantum behaviors in nanoscale systems. PMID:27363671

Bas-Relief Modeling from Normal Images with Intuitive Styles.

PubMed

Ji, Zhongping; Ma, Weiyin; Sun, Xianfang

2014-05-01

Traditional 3D model-based bas-relief modeling methods are often limited to model-dependent and monotonic relief styles. This paper presents a novel method for digital bas-relief modeling with intuitive style control. Given a composite normal image, the problem discussed in this paper involves generating a discontinuity-free depth field with high compression of depth data while preserving or even enhancing fine details. In our framework, several layers of normal images are composed into a single normal image. The original normal image on each layer is usually generated from 3D models or through other techniques as described in this paper. The bas-relief style is controlled by choosing a parameter and setting a targeted height for them. Bas-relief modeling and stylization are achieved simultaneously by solving a sparse linear system. Different from previous work, our method can be used to freely design bas-reliefs in normal image space instead of in object space, which makes it possible to use any popular image editing tools for bas-relief modeling. Experiments with a wide range of 3D models and scenes show that our method can effectively generate digital bas-reliefs.

Resource letter SH-1: superfluid helium

NASA Astrophysics Data System (ADS)

Hallock, Robert B.

1982-03-01

The resource letter covers the general subject of superfluid helium and treats 3He and 3He-4He mixtures as well as 4He. No effort has been made to include the fascinating experiments on either solid helium or the equally fascinating work on adsorbed helium where the helium coverage is below that necessary for superfluidity. An earlier resource letter by C. T. Lane [Am. J. Phys. 35, 367 (1967)] may be consulted for additional comments on some of the cited earlier manuscripts, but the present work is self-contained and may be used independently. Many high-quality research reports have not been cited here. Rather, the author has tried in most cases to include works particularly readable or relevant. There is a relatively heavy emphasis on experimental references. The primary reason is that these works tend to be more generally readable. No doubt some works that might have been included, have not, and for this the author takes responsibility with apology. Articles selected for incorporation in a reprint volume (to be published separately by the American Association of Physics Teachers) are marked with an asterisk(*). Following each referenced work the general level of difficulty is indicated by E, I, or A for elementary, intermediate, or advanced.

Analysis of Helium Segregation on Surfaces of Plasma-Exposed Tungsten

NASA Astrophysics Data System (ADS)

Maroudas, Dimitrios; Hu, Lin; Hammond, Karl; Wirth, Brian

2015-11-01

We report a systematic theoretical and atomic-scale computational study of implanted helium segregation on surfaces of tungsten, which is considered as a plasma facing component in nuclear fusion reactors. We employ a hierarchy of atomic-scale simulations, including molecular statics to understand the origin of helium surface segregation, targeted molecular-dynamics (MD) simulations of near-surface cluster reactions, and large-scale MD simulations of implanted helium evolution in plasma-exposed tungsten. We find that small, mobile helium clusters (of 1-7 He atoms) in the near-surface region are attracted to the surface due to an elastic interaction force. This thermodynamic driving force induces drift fluxes of these mobile clusters toward the surface, facilitating helium segregation. Moreover, the clusters' drift toward the surface enables cluster reactions, most importantly trap mutation, at rates much higher than in the bulk material. This cluster dynamics has significant effects on the surface morphology, near-surface defect structures, and the amount of helium retained in the material upon plasma exposure.

L'Aventure du LHC

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-06-11

Cette présentation s’adressera principalement aux personnes qui ont construit le LHC. La construction du LHC fut longue et difficile. De nombreux problèmes sont apparus en cours de route. Tous ont été résolus grâce au dévouement et à l’engagement du personnel et des collaborateurs. Je reviendrai sur les coups durs et les réussites qui ont marqués ces 15 dernières années et je vous montrerai combien cette machine, le fruit de vos efforts, est extraordinaire.

Effect of carbon and alloying solute atoms on helium behaviors in α-Fe

NASA Astrophysics Data System (ADS)

Zhang, Yange; You, Yu-Wei; Xu, Yichun; Liu, C. S.; Chen, J. L.; Luo, G.-N.

2017-02-01

Helium bubbles could strongly degrade the mechanical properties of ferritic steels in fission and fusion systems. The formation of helium bubble is directly affected by the interactions between helium and the compositions in steels, such as solute atoms, carbon and irradiation defects. We thereby performed systematical first-principles calculations to investigate the interactions of solute-helium and carbon-solute-helium. It is found that substitutional helium is more attractive than interstitial helium to all the considered 3p, 4p, 5p and 6p solutes. The attraction between carbon and substitutional helium suggests the carbon-solute-helium complex can be formed stably. By examining the charge density difference and thermal stability, it is found that the ternary complex shows stronger attraction with He than that of solute-helium pair for some solutes (S, Se, In, Te, Pb and Bi) and the complex could existed in iron stably at 700 K. The present theoretical results may be helpful for exploring alloy additions to mitigate the formation of large helium bubbles.

49 CFR 179.500-12 - Pressure relief devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure relief devices. 179.500-12 Section 179... Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of...

49 CFR 179.500-12 - Pressure relief devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure relief devices. 179.500-12 Section 179... Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of...

49 CFR 179.500-12 - Pressure relief devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure relief devices. 179.500-12 Section 179... Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of...

49 CFR 179.500-12 - Pressure relief devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure relief devices. 179.500-12 Section 179... Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of...

Theoretical model of the helium zone plate microscope

NASA Astrophysics Data System (ADS)

Salvador Palau, Adrià; Bracco, Gianangelo; Holst, Bodil

2017-01-01

Neutral helium microscopy is a new technique currently under development. Its advantages are the low energy, charge neutrality, and inertness of the helium atoms, a potential large depth of field, and the fact that at thermal energies the helium atoms do not penetrate into any solid material. This opens the possibility, among others, for the creation of an instrument that can measure surface topology on the nanoscale, even on surfaces with high aspect ratios. One of the most promising designs for helium microscopy is the zone plate microscope. It consists of a supersonic expansion helium beam collimated by an aperture (skimmer) focused by a Fresnel zone plate onto a sample. The resolution is determined by the focal spot size, which depends on the size of the skimmer, the optics of the system, and the velocity spread of the beam through the chromatic aberrations of the zone plate. An important factor for the optics of the zone plate is the width of the outermost zone, corresponding to the smallest opening in the zone plate. The width of the outermost zone is fabrication limited to around 10 nm with present-day state-of-the-art technology. Due to the high ionization potential of neutral helium atoms, it is difficult to build efficient helium detectors. Therefore, it is crucial to optimize the microscope design to maximize the intensity for a given resolution and width of the outermost zone. Here we present an optimization model for the helium zone plate microscope. Assuming constant resolution and width of the outermost zone, we are able to reduce the problem to a two-variable problem (zone plate radius and object distance) and we show that for a given beam temperature and pressure, there is always a single intensity maximum. We compare our model with the highest-resolution zone plate focusing images published and show that the intensity can be increased seven times. Reducing the width of the outermost zone to 10 nm leads to an increase in intensity of more than 8000

Germanium resistance thermometer calibration at superfluid helium temperatures

NASA Technical Reports Server (NTRS)

Mason, F. C.

1985-01-01

The rapid increase in resistance of high purity semi-conducting germanium with decreasing temperature in the superfluid helium range of temperatures makes this material highly adaptable as a very sensitive thermometer. Also, a germanium thermometer exhibits a highly reproducible resistance versus temperature characteristic curve upon cycling between liquid helium temperatures and room temperature. These two factors combine to make germanium thermometers ideally suited for measuring temperatures in many cryogenic studies at superfluid helium temperatures. One disadvantage, however, is the relatively high cost of calibrated germanium thermometers. In space helium cryogenic systems, many such thermometers are often required, leading to a high cost for calibrated thermometers. The construction of a thermometer calibration cryostat and probe which will allow for calibrating six germanium thermometers at one time, thus effecting substantial savings in the purchase of thermometers is considered.

Performance of an efficient Helium Circulation System on a MEG

NASA Astrophysics Data System (ADS)

Takeda, T.; Okamoto, M.; Atsuda, K.; Katagiri, K.

2009-02-01

We report a Helium Circulation System (HCS) that re-liquefies all the evaporating helium gas, consumes far less power and has extremely lower magnetic noise compared with conventional systems. It collects warm helium gas about 300 K, cools it to about 40K and returns it to the neck tube of the Dewar to keep it cold. It also collects helium gas just above the liquid helium surface while it is still cold, re-liquefies and returns it to the Dewar. A special transfer tube (TT) about 2 m length with 7 multi-concentric pipes was developed to allow the dual helium streams. It separates the HCS with a MEG to reduce magnetic noise. A refiner to collect the contaminating gases such as oxygen and nitrogen effectively by freezing the gases is developed. It has an electric heater to remove the frozen contamination in the form of gases into the air. A gas flow controller is also developed, which automatically control the heater to cleanup the contamination. The developed TT has very low heat inflow less than 0.1W/m to the liquid helium ensuring the efficient operation. The HCS can re-liquefy up to 35.5 1/D of liquid helium from the evaporated helium gas using two 1.5W@4.2K GM cryocoolers (SRDK-415D, Sumitomo Heavy Industries, Ltd.). It has been confirmed that the HCS could be used with the real MEG system without any noise problem for over one year. The maintenance cost (electricity charges and cryocoolers maintenance fee) of the MEG has reduced to be less than 1/10 of the previous cost.

Overview of LHC physics results at ICHEP

ScienceCinema

Mangano, Michelangelo

2018-06-20

This month LHC physics day will review the physics results presented by the LHC experiments at the 2010 ICHEP in Paris. The experimental presentations will be preceeded by the bi-weekly LHC accelerator status report.The meeting will be broadcast via EVO (detailed info will appear at the time of the meeting in the "Video Services" item on the left menu bar). For those attending, information on accommodation, access to CERN and laptop registration is available from http://cern.ch/lpcc/visits

Helium recovery at the National High Magnetic Field Laboratory

NASA Astrophysics Data System (ADS)

Barrios, M.; Kynoch, J.

2015-12-01

Helium conservation is becoming increasingly important as helium availability is on the decline and prices are on the rise. The Florida State University National High Magnetic Field Laboratory has taken several steps over the past five years to increase the percentage of helium recovered. These include the installation of a standalone purifier, recovery flow meters, contamination meters, and a new piping system. The improvements to the recovery system have reduced the amount of helium purchased by the Mag Lab by 60% while helium usage has increased by roughly 40%. This article will provide details about the recovery system as a whole and describe some of the main components. There will also be some examples of the problems we've had to overcome, and some that we are still working on. Finally, there will be an update on the current status of the recovery system and a description of our plans for the future.

Helium sequestration at nanoparticle-matrix interfaces in helium + heavy ion irradiated nanostructured ferritic alloys

DOE PAGES

Parish, Chad M.; Unocic, Kinga A.; Tan, Lizhen; ...

2016-10-24

Here we irradiated four ferritic alloys with energetic Fe and He ions: one castable nanostructured alloy (CNA) containing Ti-W-Ta-carbides, and three nanostructured ferritic alloys (NFAs). The NFAs were: 9Cr containing Y-Ti-O nanoclusters, and two Fe-12Cr-5Al NFAs containing Y-Zr-O or Y-Hf-O clusters. All four were subjected to simultaneous dual-beam Fe + He ion implantation (650 °C, ~50 dpa, ~15 appm He/dpa), simulating fusion-reactor conditions. Examination using scanning/transmission electron microscopy (STEM) revealed high-number-density helium bubbles of ~8 nm, ~10 21 m -3 (CNA), and of ~3 nm, 10 23 m -3 (NFAs). STEM combined with multivariate statistical analysis data mining suggests thatmore » the precipitate-matrix interfaces in all alloys survived ~50 dpa at 650 °C and serve as effective helium trapping sites. All alloys appear viable structural material candidates for fusion or advanced fission energy systems. Finally, among these developmental alloys the NFAs appear to sequester the helium into smaller bubbles and away from the grain boundaries more effectively than the early-generation CNA.« less

49 CFR 601.42 - Emergency relief docket.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Emergency Relief Docket in the publicly accessible DOT Docket Management System (DMS) (http://dms.dot.gov... message on its web page (http://www.fta.dot.gov) indicating the Emergency Relief Docket has been opened...

49 CFR 601.42 - Emergency relief docket.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Emergency Relief Docket in the publicly accessible DOT Docket Management System (DMS) (http://dms.dot.gov... message on its web page (http://www.fta.dot.gov) indicating the Emergency Relief Docket has been opened...

49 CFR 601.42 - Emergency relief docket.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Emergency Relief Docket in the publicly accessible DOT Docket Management System (DMS) (http://dms.dot.gov... message on its web page (http://www.fta.dot.gov) indicating the Emergency Relief Docket has been opened...

49 CFR 601.42 - Emergency relief docket.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Emergency Relief Docket in the publicly accessible DOT Docket Management System (DMS) (http://dms.dot.gov... message on its web page (http://www.fta.dot.gov) indicating the Emergency Relief Docket has been opened...

49 CFR 601.42 - Emergency relief docket.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Emergency Relief Docket in the publicly accessible DOT Docket Management System (DMS) (http://dms.dot.gov... message on its web page (http://www.fta.dot.gov) indicating the Emergency Relief Docket has been opened...

Survey of natural helium occurrences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinnah, D.W.; Hamak, J.E.

1993-01-01

Since 1917, gas samples from oil and gas wells and natural gas pipelines throughout the United States and other countries worldwide have been collected by the USBM in a continuing search for helium occurrences. Analyses of 15,583 of the samples, which were collected from 40 States and 26 foreign countries, are available from the USBM. The USBM is charged with the responsibility of ensuring a continuing supply of helium to meet essential Government needs, and this survey of the world's natural gas fields is made in connection with this responsibility. Most of these analyses have been published in USBM publications.more » The first of this series of publications was Bulletin 486 and was followed by two more bulletins. These three publications contained data on analyses of 5,218 gas samples collected from the beginning of the survey through 1960. Data on gas analyses since 1961 have been published on an annual basis, and 35 Information Circulars have presented the analyses of 10,365 gas samples collected through 1991. These analyses are also available on magnetic tape and 3.5-inch diskettes from the National Technical Information Service. The helium survey program is conducted by soliciting natural gas samples throughout the United States and from other countries with free market economies. Without the assistance of the oil and gas industry, State and National agencies, and many individuals engaged in oil and gas exploration and production, the present scope of the helium survey would have been impossible. 39 refs., 3 tabs.« less

LHC: The Emptiest Space in the Solar System

ERIC Educational Resources Information Center

Cid-Vidal, Xabier; Cid, Ramon

2011-01-01

Proton beams have been colliding at 7 TeV in the Large Hadron Collider (LHC) since 30 March 2010, meaning that the LHC research programme is underway. Particle physicists around the world are looking forward to using the data from these collisions, as the LHC is running at an energy three and a half times higher than previously achieved at any…

Helium Speech: An Application of Standing Waves

ERIC Educational Resources Information Center

Wentworth, Christopher D.

2011-01-01

Taking a breath of helium gas and then speaking or singing to the class is a favorite demonstration for an introductory physics course, as it usually elicits appreciative laughter, which serves to energize the class session. Students will usually report that the helium speech "raises the frequency" of the voice. A more accurate description of the…

Cryogenics for HL-LHC

NASA Astrophysics Data System (ADS)

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.

Helium extraction and nitrogen removal from LNG boil-off gas

NASA Astrophysics Data System (ADS)

Xiong, L.; Peng, N.; Liu, L.; Gong, L.

2017-02-01

The helium bearing boil off gas (BOG) from liquid natural gas (LNG) storage tank in LNG plant, which has a helium concentration of about 1%, has attracted the attention in China as a new helium source. As the BOG is usually reused by re-condensing to recover methane, it is likely to cause continuous accumulation of nitrogen in the unit, thus a nitrogen removal process must be integrated. This paper describes a conceptional cryogenic separation system aiming at recovering methane, helium and nitrogen from BOG based on cryogenic distillation and condensation process.

29 CFR 553.225 - Early relief.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 3 2011-07-01 2011-07-01 false Early relief. 553.225 Section 553.225 Labor Regulations... Enforcement Employees of Public Agencies Tour of Duty and Compensable Hours of Work Rules § 553.225 Early... employees on the previous shift prior to the scheduled starting time. Such early relief time may occur...

29 CFR 553.225 - Early relief.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Early relief. 553.225 Section 553.225 Labor Regulations... Enforcement Employees of Public Agencies Tour of Duty and Compensable Hours of Work Rules § 553.225 Early... employees on the previous shift prior to the scheduled starting time. Such early relief time may occur...

Reward, motivation and emotion of pain and its relief

PubMed Central

Porreca, Frank; Navratilova, Edita

2016-01-01

The experience of pain depends on interpretation of context and past experience that guide the choice of an immediate behavioral response and influence future decisions of actions to avoid harm. The aversive qualities of pain underlie its physiological role in learning and motivation. In this review, we highlight findings from human and animal investigations that suggest that both pain, and the relief of pain, are complex emotions that are comprised of feelings and their motivational consequences. Relief of aversive states, including pain, is rewarding. How relief of pain aversiveness occurs is not well understood. Termination of aversive states can directly provide relief as well as reinforce behaviors that result in avoidance of pain. Emerging preclinical data also suggests that relief may elicit a positive hedonic value that results from activation of neural cortical and mesolimbic brain circuits that may also motivate behavior. Brain circuits mediating the reward of pain relief, as well as relief-induced motivation are significantly impacted as pain becomes chronic. In chronic pain states, the negative motivational value of nociception may be increased while the value of the reward of pain relief may decrease. As a consequence, the impact of pain on these ancient, and conserved brain limbic circuits suggest a path forward for discovery of new pain therapies. PMID:28106670

Overview of LHC physics results at ICHEP

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2011-02-25

 This month LHC physics day will review the physics results presented by the LHC experiments at the 2010 ICHEP in Paris. The experimental presentations will be preceeded by the bi-weekly LHC accelerator status report.The meeting will be broadcast via EVO (detailed info will appear at the time of the meeting in the "Video Services" item on the left menu bar)For those attending, information on accommodation, access to CERN and laptop registration is available from http://cern.ch/lpcc/visits

A sigh of relief or a sigh to relieve: The psychological and physiological relief effect of deep breaths.

PubMed

Vlemincx, Elke; Van Diest, Ilse; Van den Bergh, Omer

2016-10-15

Both animal and human research have revealed important associations between sighs and relief. Previously we argued to conceive of sighs as resetters which temporarily induce relief. The present study aimed to investigate the psychological and physiological relief effect of sighs by instructed deep breaths and spontaneous sighs compared to a control breathing maneuver. Participants completed three blocks of 40 trials during which uncertainty cues were followed by either safety cues followed by a positive picture, or danger cues followed by a negative picture. One block was presented without breathing instructions, two subsequent blocks with breathing instructions. During the presentation of the safety and danger cues, an instruction was given to either 'take a deep breath' or 'postpone the next inhalation for 2 s (breath hold). Continuously, participants rated relief and Frontalis electromyography was recorded. Trait anxiety sensitivity was assessed by the Anxiety Sensitivity Index. Self-reported relief and physiological tension were compared 5s before and after instructed deep breaths and breath holds, and before and after spontaneous deep breaths and breath holds in the respective blocks. Results show that self-reported relief following an instructed deep breath was higher than before. Physiological tension decreased following a spontaneous sigh in high anxiety sensitive persons and following a spontaneous breath hold in low anxiety sensitive persons. These results are the first to show that a deep breath relieves and, in anxiety sensitive persons, reduces physiological tension. These findings support the hypothesis that sighs are psychological and physiological resetters. Copyright © 2016 Elsevier Inc. All rights reserved.

Cosmic Ray Helium Intensities over the Solar Cycle from ACE

NASA Technical Reports Server (NTRS)

DeNolfo, G. A.; Yanasak, N. E.; Binns, W. R.; Cohen, C. M. S.; Cummings, A. C.; Davis, A. J.; George, J. S.; Hink. P. L.; Israel, M. H.; Lave, K.;

New Physics Undercover at the LHC

NASA Astrophysics Data System (ADS)

Lou, Hou Keong

With the completion of 7 TeV and 8 TeV data taking at the Large Hadron Collider (LHC), the physics community witnessed one of the great triumphs of modern physics: the completion of the Standard Model (SM) as an effective theory. The final missing particle, the Higgs boson, was observed and its mass was measured. However, many theoretical questions remain unanswered. What is the source of electroweak symmetry breaking? What is the nature of dark matter? How does gravity fit into the picture? With no definitive hints of new physics at the LHC, we must consider the possibility that our search strategies need to be expanded. Conventional LHC searches focus on theoretically motivated scenarios, such as the Minimal Supersymmetric Standard Models and Little Higgs Theories. However, it is possible that new physics may be entirely different from what we might expect. In this thesis, we examine a variety of scenarios that lead to new physics undercover at the LHC. First we look at potential new physics hiding in Quantum Chromo-Dynamics backgrounds, which may be uncovered using jet substructure techniques in a data-driven way. Then we turn to new long-lived particles hiding in Higgs decay, which may lead to displaced vertices. Such a signal can be unearthed through a data-driven analysis. Then we turn to new physics with ``semi-visible jets'', which lead to missing momentum aligned with jet momentum. These events are vetoed in traditional searches and we demonstrate ways to uncover these signals. Lastly, we explore performance of future colliders in two case studies: Stops and Higgs Portal searches. We show that a 100 TeV collider will lead to significant improvements over 14 TeV LHC runs. Indeed, new physics may lie undercover at the LHC and future colliders, waiting to be discovered.

HEATHER - HElium Ion Accelerator for RadioTHERapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Jordan; Edgecock, Thomas; Green, Stuart

2017-05-01

A non-scaling fixed field alternating gradient (nsFFAG) accelerator is being designed for helium ion therapy. This facility will consist of 2 superconducting rings, treating with helium ions (He²⁺ ) and image with hydrogen ions (H + 2 ). Currently only carbon ions are used to treat cancer, yet there is an increasing interest in the use of lighter ions for therapy. Lighter ions have reduced dose tail beyond the tumour compared to carbon, caused by low Z secondary particles produced via inelastic nuclear reactions. An FFAG approach for helium therapy has never been previously considered. Having demonstrated isochronous acceleration frommore » 0.5 MeV to 900 MeV, we now demonstrate the survival of a realistic beam across both stages.« less

Helium in the eroding atmosphere of an exoplanet.

PubMed

Spake, J J; Sing, D K; Evans, T M; Oklopčić, A; Bourrier, V; Kreidberg, L; Rackham, B V; Irwin, J; Ehrenreich, D; Wyttenbach, A; Wakeford, H R; Zhou, Y; Chubb, K L; Nikolov, N; Goyal, J M; Henry, G W; Williamson, M H; Blumenthal, S; Anderson, D R; Hellier, C; Charbonneau, D; Udry, S; Madhusudhan, N

2018-05-01

Helium is the second-most abundant element in the Universe after hydrogen and is one of the main constituents of gas-giant planets in our Solar System. Early theoretical models predicted helium to be among the most readily detectable species in the atmospheres of exoplanets, especially in extended and escaping atmospheres 1 . Searches for helium, however, have hitherto been unsuccessful 2 . Here we report observations of helium on an exoplanet, at a confidence level of 4.5 standard deviations. We measured the near-infrared transmission spectrum of the warm gas giant 3 WASP-107b and identified the narrow absorption feature of excited metastable helium at 10,833 angstroms. The amplitude of the feature, in transit depth, is 0.049 ± 0.011 per cent in a bandpass of 98 angstroms, which is more than five times greater than what could be caused by nominal stellar chromospheric activity. This large absorption signal suggests that WASP-107b has an extended atmosphere that is eroding at a total rate of 10 10 to 3 × 10 11 grams per second (0.1-4 per cent of its total mass per billion years), and may have a comet-like tail of gas shaped by radiation pressure.

Helium in the eroding atmosphere of an exoplanet

NASA Astrophysics Data System (ADS)

Spake, J. J.; Sing, D. K.; Evans, T. M.; Oklopčić, A.; Bourrier, V.; Kreidberg, L.; Rackham, B. V.; Irwin, J.; Ehrenreich, D.; Wyttenbach, A.; Wakeford, H. R.; Zhou, Y.; Chubb, K. L.; Nikolov, N.; Goyal, J. M.; Henry, G. W.; Williamson, M. H.; Blumenthal, S.; Anderson, D. R.; Hellier, C.; Charbonneau, D.; Udry, S.; Madhusudhan, N.

2018-05-01

Helium is the second-most abundant element in the Universe after hydrogen and is one of the main constituents of gas-giant planets in our Solar System. Early theoretical models predicted helium to be among the most readily detectable species in the atmospheres of exoplanets, especially in extended and escaping atmospheres1. Searches for helium, however, have hitherto been unsuccessful2. Here we report observations of helium on an exoplanet, at a confidence level of 4.5 standard deviations. We measured the near-infrared transmission spectrum of the warm gas giant3 WASP-107b and identified the narrow absorption feature of excited metastable helium at 10,833 angstroms. The amplitude of the feature, in transit depth, is 0.049 ± 0.011 per cent in a bandpass of 98 angstroms, which is more than five times greater than what could be caused by nominal stellar chromospheric activity. This large absorption signal suggests that WASP-107b has an extended atmosphere that is eroding at a total rate of 1010 to 3 × 1011 grams per second (0.1-4 per cent of its total mass per billion years), and may have a comet-like tail of gas shaped by radiation pressure.

Dark Matter Detection Using Helium Evaporation and Field Ionization.

PubMed

Maris, Humphrey J; Seidel, George M; Stein, Derek

2017-11-03

We describe a method for dark matter detection based on the evaporation of helium atoms from a cold surface and their subsequent detection using field ionization. When a dark matter particle scatters off a nucleus of the target material, elementary excitations (phonons or rotons) are produced. Excitations which have an energy greater than the binding energy of helium to the surface can result in the evaporation of helium atoms. We propose to detect these atoms by ionizing them in a strong electric field. Because the binding energy of helium to surfaces can be below 1 meV, this detection scheme opens up new possibilities for the detection of dark matter particles in a mass range down to 1  MeV/c^{2}.

Dark Matter Detection Using Helium Evaporation and Field Ionization

NASA Astrophysics Data System (ADS)

Maris, Humphrey J.; Seidel, George M.; Stein, Derek

2017-11-01

We describe a method for dark matter detection based on the evaporation of helium atoms from a cold surface and their subsequent detection using field ionization. When a dark matter particle scatters off a nucleus of the target material, elementary excitations (phonons or rotons) are produced. Excitations which have an energy greater than the binding energy of helium to the surface can result in the evaporation of helium atoms. We propose to detect these atoms by ionizing them in a strong electric field. Because the binding energy of helium to surfaces can be below 1 meV, this detection scheme opens up new possibilities for the detection of dark matter particles in a mass range down to 1 MeV /c2 .

A Cryogen Recycler with Pulse Tube Cryocooler for Recondensing Helium and Nitrogen

NASA Astrophysics Data System (ADS)

Wang, C.; Lichtenwalter, B.

2015-12-01

We have developed a cryogen recycler using a 4 K pulse tube cryocooler for recondensing helium and nitrogen in a NMR magnet. The liquid helium cooled NMR magnet has a liquid nitrogen cooled radiation shield. The magnet boils off 0.84 L/day of liquid helium and 6 L/day of liquid nitrogen. The recycler is designed with both a liquid helium return tube and a liquid nitrogen return tube, which are inserted into the fill ports of liquid helium and nitrogen. Therefore the recycler forms closed loops for helium and nitrogen. A two-stage 4 K pulse tube cryocooler, Cryomech model PT407 (0.7W at 4.2 K), is selected for the recycler. The recycler was first tested with a Cryomech's test cryostat and resulted in the capacities of recondensing 8.2 L/day of nitrogen and liquefying 4 L/day of helium from room temperature gas. The recycler has been installed in the NMR magnet at University of Sydney since August, 2014 and continuously maintains a zero boil off for helium and nitrogen.

Southern Alaska Coastal Relief Model

NASA Astrophysics Data System (ADS)

Lim, E.; Eakins, B.; Wigley, R.

2009-12-01

The National Geophysical Data Center (NGDC), an office of the National Oceanic and Atmospheric Administration (NOAA), in conjunction with the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado at Boulder, has developed a 24 arc-second integrated bathymetric-topographic digital elevation model of Southern Alaska. This Coastal Relief Model (CRM) was generated from diverse digital datasets that were obtained from NGDC, the United States Geological Survey, and other U.S. and international agencies. The CRM spans 170° to 230° E and 48.5° to 66.5° N, including the Gulf of Alaska, Bering Sea, Aleutian Islands, and Alaska’s largest communities: Anchorage, Fairbanks, and Juneau. The CRM provides a framework for enabling scientists to refine tsunami propagation and ocean circulation modeling through increased resolution of geomorphologic features. It may also be useful for benthic habitat research, weather forecasting, and environmental stewardship. Shaded-relief image of the Southern Alaska Coastal Relief Model.

Superfluid Helium Tanker (SFHT) study

NASA Technical Reports Server (NTRS)

Eberhardt, Ralph N.; Dominick, Sam M.; Anderson, John E.; Gille, John P.; Martin, Tim A.; Marino, John S.; Paynter, Howard L.; Traill, R. Eric; Herzl, Alfred; Gotlib, Sam

1988-01-01

Replenishment of superfluid helium (SFHe) offers the potential of extending the on-orbit life of observatories, satellite instruments, sensors and laboratories which operate in the 2 K temperature regime. A reference set of resupply customers was identified as representing realistic helium servicing requirements and interfaces for the first 10 years of superfluid helium tanker (SFHT) operations. These included the Space Infrared Telescope Facility (SIRTF), the Advanced X-ray Astrophysics Facility (AXAF), the Particle Astrophysics Magnet Facility (Astromag), and the Microgravity and Materials Processing Sciences Facility (MMPS)/Critical Point Phenomena Facility (CPPF). A mixed-fleet approach to SFHT utilization was considered. The tanker permits servicing from the Shuttle cargo bay, in situ when attached to the OMV and carried to the user spacecraft, and as a depot at the Space Station. A SFHT Dewar ground servicing concept was developed which uses a dedicated ground cooling heat exchanger to convert all the liquid, after initial fill as normal fluid, to superfluid for launch. This concept permits the tanker to be filled to a near full condition, and then cooled without any loss of fluid. The final load condition can be saturated superfluid with any desired ullage volume, or the tank can be totally filed and pressurized. The SFHT Dewar and helium plumbing system design has sufficient component redundancy to meet fail-operational, fail-safe requirements, and is designed structurally to meet a 50 mission life usage requirement. Technology development recommendations were made for the selected SFHT concept, and a Program Plan and cost estimate prepared for a phase C/D program spanning 72 months from initiation through first launch in 1997.

22 countries: tax relief for vaccines, ORS, and contraceptives.

PubMed

Krasovec, K; Connor, C

1999-01-01

This article presents the implementation of tax relief of the three key public health commodities--vaccines, oral rehydration salts (ORS), and contraceptives--in 22 countries. Tax relief was provided in the form of exemptions, waivers, reductions or some combination thereof, with the goal of improving the health status of the population. Tax relief is known to aid in the achievement of policy objectives, which include reduction of buyer's administrative cost, and budget needs, reduction of consumer prices and increase of product supply. Through a global e-mail survey in 1997, information on vaccine, ORS, and contraceptive tax exemptions was gathered. Results revealed that 68% of the countries granted tax relief. It was observed that 87% of the public sector benefits from tax relief for at least one commodity, 67% of the private nonprofit sector, and 53% of the private for-profit sector. On the other hand, the use of waiver procedures for tax relief greatly differs across countries. It was noted that tax exemptions rather than waiver procedures result in the greatest benefits. This article suggests further expansion of private nonprofit and for-profit sectors with appropriate guarantees of consumer savings, as well as implementation of tax relief.

Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone

USGS Publications Warehouse

Lowenstern, Jacob B.; Evans, William C.; Bergfeld, D.; Hunt, Andrew G.

2014-01-01

Helium is used as a critical tracer throughout the Earth sciences, where its relatively simple isotopic systematics is used to trace degassing from the mantle, to date groundwater and to time the rise of continents1. The hydrothermal system at Yellowstone National Park is famous for its high helium-3/helium-4 isotope ratio, commonly cited as evidence for a deep mantle source for the Yellowstone hotspot2. However, much of the helium emitted from this region is actually radiogenic helium-4 produced within the crust by α-decay of uranium and thorium. Here we show, by combining gas emission rates with chemistry and isotopic analyses, that crustal helium-4 emission rates from Yellowstone exceed (by orders of magnitude) any conceivable rate of generation within the crust. It seems that helium has accumulated for (at least) many hundreds of millions of years in Archaean (more than 2.5 billion years old) cratonic rocks beneath Yellowstone, only to be liberated over the past two million years by intense crustal metamorphism induced by the Yellowstone hotspot. Our results demonstrate the extremes in variability of crustal helium efflux on geologic timescales and imply crustal-scale open-system behaviour of helium in tectonically and magmatically active regions.

The Descending Helium Balloon

ERIC Educational Resources Information Center

Helseth, Lars Egil

2014-01-01

I describe a simple and fascinating experiment wherein helium leaks out of a rubber balloon, thereby causing it to descend. An estimate of the volumetric leakage rate is made by measuring its rate of descent.

Improved Helium-Barrier Bag

NASA Technical Reports Server (NTRS)

Viger, Brent J.; Logan, Robert F.; Fink, Jeffrey E.

1992-01-01

Specially designed bag maintains helium atmosphere around large, low-temperature duct. Easy to install, durable, and reusable. Intended to prevent cryopumping occurring if air or nitrogen allowed to make contact with cold surface of duct.

Hydrogen and helium shell burning during white dwarf accretion

NASA Astrophysics Data System (ADS)

Cui, Xiao; Meng, Xiang-Cun; Han, Zhan-Wen

2018-05-01

Type Ia supernovae (SNe Ia) are believed to be thermonuclear explosions of carbon oxygen (CO) white dwarfs (WDs) with masses close to the Chandrasekhar mass limit. How a CO WD accretes matter and grows in mass to this limit is not well understood, hindering our understanding of SN Ia explosions and the reliability of using SNe Ia as a cosmological distance indicator. In this work, we employed the stellar evolution code MESA to simulate the accretion process of hydrogen-rich material onto a 1.0 M ⊙ CO WD at a high rate (over the Eddington limit) of 4.3 × 10‑7 M ⊙ yr‑1. The simulation demonstrates the characteristics of the double shell burning on top of the WD, with a hydrogen shell burning on top of a helium burning shell. The results show that helium shell burning is not steady (i.e. it flashes). Flashes from the helium shell are weaker than those in the case of accretion of helium-rich material onto a CO WD. The carbon to oxygen mass ratio resulting from the helium shell burning is higher than what was previously thought. Interestingly, the CO WD growing due to accretion has an outer part containing a small fraction of helium in addition to carbon and oxygen. The flashes become weaker and weaker as the accretion continues.

Geometric beam coupling impedance of LHC secondary collimators

NASA Astrophysics Data System (ADS)

Frasciello, Oscar; Tomassini, Sandro; Zobov, Mikhail; Salvant, Benoit; Grudiev, Alexej; Mounet, Nicolas

2016-02-01

The High Luminosity LHC project is aimed at increasing the LHC luminosity by an order of magnitude. One of the key ingredients to achieve the luminosity goal is the beam intensity increase. In order to keep beam instabilities under control and to avoid excessive power losses a careful design of new vacuum chamber components and an improvement of the present LHC impedance model are required. Collimators are among the major impedance contributors. Measurements with beam have revealed that the betatron coherent tune shifts were higher by about a factor of 2 with respect to the theoretical predictions based on the LHC impedance model up to 2012. In that model the resistive wall impedance has been considered as the dominating impedance contribution for collimators. By carefully simulating also their geometric impedance we have contributed to the update of the LHC impedance model, reaching also a better agreement between the measured and simulated betatron tune shifts. During the just ended LHC Long Shutdown I (LSI), TCS/TCT collimators were replaced by new devices embedding BPMs and TT2-111R ferrite blocks. We present here preliminary estimations of their broad-band impedance, showing that an increase of about 20% is expected in the kick factors with respect to previous collimators without BPMs.

The development of diamond tracking detectors for the LHC

NASA Astrophysics Data System (ADS)

Adam, W.; Berdermann, E.; Bergonzo, P.; de Boer, W.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Doroshenko, J.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fischer, P.; Fizzotti, F.; Furetta, C.; Gan, K. K.; Ghodbane, N.; Grigoriev, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kaplon, J.; Karl, C.; Kass, R.; Keil, M.; Knöpfle, K. T.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; mac Lynne, L.; Manfredotti, C.; Marshall, R. D.; Meier, D.; Menichelli, D.; Meuser, S.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Perera, L.; Pernegger, H.; Pernicka, M.; Polesello, P.; Potenza, R.; Riester, J. L.; Roe, S.; Rudge, A.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Sutera, C.; Trischuk, W.; Tromson, D.; Tuve, C.; Vincenzo, B.; Weilhammer, P.; Wermes, N.; Wetstein, M.; Zeuner, W.; Zoeller, M.; RD42 Collaboration

2003-11-01

Chemical vapor deposition diamond has been discussed extensively as an alternate sensor material for use very close to the interaction region of the LHC where extreme radiation conditions exist. During the last few years diamond devices have been manufactured and tested with LHC electronics with the goal of creating a detector usable by all LHC experiment. Extensive progress on diamond quality, on the development of diamond trackers and on radiation hardness studies has been made. Transforming the technology to the LHC specific requirements is now underway. In this paper we present the recent progress achieved.

Glass-to-Metal Seal Against Liquid Helium

NASA Technical Reports Server (NTRS)

Watkins, John L.; Gatewood, John R.

1987-01-01

Simple compression joint with indium gasket forms demountable seal for superfluids. Seal developed for metal lid on glass jar used in experiments on liquid helium. Glass container allows contents to be viewed for such purposes as calibration of liquid-level detectors and adjustments of displacement plungers. Seal contains liquid helium even when temperature drops below 2.19K. Made from inexpensive, commercially available materials and parts.

Irreversible adsorption of atmospheric helium on olivine: A lobster pot analogy

NASA Astrophysics Data System (ADS)

Protin, Marie; Blard, Pierre-Henri; Marrocchi, Yves; Mathon, François

2016-04-01

This study reports new experimental results that demonstrate that large amounts of atmospheric helium may be adsorbed onto the surfaces of olivine grains. This behavior is surface-area-related in that this contamination preferentially affects grains that are smaller than 125 μm in size. One of the most striking results of our study is that in vacuo heating at 900 °C for 15 min is not sufficient to completely remove the atmospheric contamination. This suggests that the adsorption of helium may involve high-energy trapping of helium through irreversible anomalous adsorption. This trapping process of helium can thus be compared to a ;lobster pot; adsorption: atmospheric helium easily gets in, but hardly gets out. While this type of behavior has previously been reported for heavy noble gases (Ar, Kr, Xe), this is the first time that it has been observed for helium. Adsorption of helium has, until now, generally been considered to be negligible on silicate surfaces. Our findings have significant implications for helium and noble gas analysis of natural silicate samples, such as for cosmic-ray exposure dating or noble gas characterization of extraterrestrial material. Analytical procedures in future studies should be adapted in order to avoid this contamination. The results of this study also allow us to propose an alternative explanation for previously described matrix loss of cosmogenic 3He.

Laser Spectroscopy of Radicals, Carbenes, and Ions in Superfluid Helium Droplets

NASA Astrophysics Data System (ADS)

Douberly, Gary E.

2015-06-01

The first beam of helium droplets was reported in the 1961 paper Strahlen aus kondensiertem Helium im Hochvakuum by Von E. W. Becker and co-workers. However, molecular spectroscopy of helium-solvated dopants wasn't realized until 30 years later in the laboratories of Scoles and Toennies. It has now been two decades since this early, seminal work on doped helium droplets, yet the field of helium droplet spectroscopy is still fresh with vast potential. Analogous in many ways to cryogenic matrix isolation spectroscopy, the helium droplet is an ideal environment to spectroscopically probe difficult to prepare molecular species, such as radicals, carbenes and ions. The quantum nature of helium at 0.35 K often results in molecular spectra that are sufficiently resolved to evoke an analysis of line shapes and fine-structure that is worthy of the International Symposium on Molecular Spectroscopy. The present talk will focus on our recent successful attempts to efficiently dope the title molecular species into helium droplets and probe their properties with infrared laser Stark and Zeeman spectroscopies. E. W. Becker, R. Klingelhöfer, P. Lohse, Z. Naturforsch. A 16A, 1259 (1961). S. Goyal, D. L. Schutt, G. Scoles, Phys. Rev. Lett. 69, 933 (1992). M. Hartmann, R. E. Miller, J. P. Toennies, A. F. Vilesov, Phys. Rev. Lett. 75, 1566, (1995).

Superconducting cable cooling system by helium gas and a mixture of gas and liquid helium

DOEpatents

Dean, John W.

1977-01-01

Thermally contacting, oppositely streaming cryogenic fluid streams in the same enclosure in a closed cycle that changes from a cool high pressure helium gas to a cooler reduced pressure helium fluid comprised of a mixture of gas and boiling liquid so as to be near the same temperature but at different pressures respectively in go and return legs that are in thermal contact with each other and in thermal contact with a longitudinally extending superconducting transmission line enclosed in the same cable enclosure that insulates the line from the ambient at a temperature T.sub.1. By first circulating the fluid in a go leg from a refrigerator at one end of the line as a high pressure helium gas near the normal boiling temperature of helium; then circulating the gas through an expander at the other end of the line where the gas becomes a mixture of reduced pressure gas and boiling liquid at its boiling temperature; then by circulating the mixture in a return leg that is separated from but in thermal contact with the gas in the go leg and in the same enclosure therewith; and finally returning the resulting low pressure gas to the refrigerator for compression into a high pressure gas at T.sub.2 is a closed cycle, where T.sub.1 >T.sub.2, the temperature distribution is such that the line temperature is nearly constant along its length from the refrigerator to the expander due to the boiling of the liquid in the mixture. A heat exchanger between the go and return lines removes the gas from the liquid in the return leg while cooling the go leg.

In situ radiation test of silicon and diamond detectors operating in superfluid helium and developed for beam loss monitoring

NASA Astrophysics Data System (ADS)

Kurfürst, C.; Dehning, B.; Sapinski, M.; Bartosik, M. R.; Eisel, T.; Fabjan, C.; Rementeria, C. A.; Griesmayer, E.; Eremin, V.; Verbitskaya, E.; Zabrodskii, A.; Fadeeva, N.; Tuboltsev, Y.; Eremin, I.; Egorov, N.; Härkönen, J.; Luukka, P.; Tuominen, E.

2015-05-01

As a result of the foreseen increase in the luminosity of the Large Hadron Collider, the discrimination between the collision products and possible magnet quench-provoking beam losses of the primary proton beams is becoming more critical for safe accelerator operation. We report the results of ongoing research efforts targeting the upgrading of the monitoring system by exploiting Beam Loss Monitor detectors based on semiconductors located as close as possible to the superconducting coils of the triplet magnets. In practice, this means that the detectors will have to be immersed in superfluid helium inside the cold mass and operate at 1.9 K. Additionally, the monitoring system is expected to survive 20 years of LHC operation, resulting in an estimated radiation fluence of 1×1016 proton/cm2, which corresponds to a dose of about 2 MGy. In this study, we monitored the signal degradation during the in situ irradiation when silicon and single-crystal diamond detectors were situated in the liquid/superfluid helium and the dependences of the collected charge on fluence and bias voltage were obtained. It is shown that diamond and silicon detectors can operate at 1.9 K after 1×1016 p/cm2 irradiation required for application as BLMs, while the rate of the signal degradation was larger in silicon detectors than in the diamond ones. For Si detectors this rate was controlled mainly by the operational mode, being larger at forward bias voltage.

The role of helium metastable states in radio-frequency driven helium-oxygen atmospheric pressure plasma jets: measurement and numerical simulation

NASA Astrophysics Data System (ADS)

Niemi, K.; Waskoenig, J.; Sadeghi, N.; Gans, T.; O'Connell, D.

2011-10-01

Absolute densities of metastable He(23S1) atoms were measured line-of-sight integrated along the discharge channel of a capacitively coupled radio-frequency driven atmospheric pressure plasma jet operated in technologically relevant helium-oxygen mixtures by tunable diode-laser absorption spectroscopy. The dependences of the He(23S1) density in the homogeneous-glow-like α-mode plasma with oxygen admixtures up to 1% were investigated. The results are compared with a one-dimensional numerical simulation, which includes a semi-kinetical treatment of the pronounced electron dynamics and the complex plasma chemistry (in total 20 species and 184 reactions). Very good agreement between measurement and simulation is found. The main formation mechanisms for metastable helium atoms are identified and analyzed, including their pronounced spatio-temporal dynamics. Penning ionization through helium metastables is found to be significant for plasma sustainment, while it is revealed that helium metastables are not an important energy carrying species into the jet effluent and therefore will not play a direct role in remote surface treatments.

Helium shell flashes and evolution of accreting white dwarfs

NASA Astrophysics Data System (ADS)

Fujimoto, M. Y.; Sugimoto, D.

1982-06-01

The evolution of accreting white dwarfs is investigated from the onset of accretion through the helium shell flash. Properties of the helium shell flashes are studied by means of a generalized theory of shell flash and by numerical computations, and it is found that the shell flash grows up to the strength of a supernova explosion when the mass of the helium zone is large enough on a massive white dwarf. Although accretion onto a hot white dwarf causes a weaker shell flash than those onto cool ones, a strong tendency exists for the strength to be determined mainly by the accretion rate. For fast accretion, the shell flashes are weak and triggered recurrently, while for slow accretion the helium shell flash, once triggered, develops into a detonation supernova.

The Hall D solenoid helium refrigeration system at JLab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laverdure, Nathaniel A.; Creel, Jonathan D.; Dixon, Kelly d.

Hall D, the new Jefferson Lab experimental facility built for the 12GeV upgrade, features a LASS 1.85 m bore solenoid magnet supported by a 4.5 K helium refrigerator system. This system consists of a CTI 2800 4.5 K refrigerator cold box, three 150 hp screw compressors, helium gas management and storage, and liquid helium and nitrogen storage for stand-alone operation. The magnet interfaces with the cryo refrigeration system through an LN2-shielded distribution box and transfer line system, both designed and fabricated by JLab. The distribution box uses a thermo siphon design to respectively cool four magnet coils and shields withmore » liquid helium and nitrogen. We describe the salient design features of the cryo system and discuss our recent commissioning experience.« less

Helium Speech: An Application of Standing Waves

NASA Astrophysics Data System (ADS)

Wentworth, Christopher D.

2011-04-01

Taking a breath of helium gas and then speaking or singing to the class is a favorite demonstration for an introductory physics course, as it usually elicits appreciative laughter, which serves to energize the class session. Students will usually report that the helium speech "raises the frequency" of the voice. A more accurate description of the phenomenon requires that we distinguish between the frequencies of sound produced by the larynx and the filtering of those frequencies by the vocal tract. We will describe here an experiment done by introductory physics students that uses helium speech as a context for learning about the human vocal system and as an application of the standing sound-wave concept. Modern acoustic analysis software easily obtained by instructors for student use allows data to be obtained and analyzed quickly.

30 CFR 203.53 - What relief will MMS grant?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false What relief will MMS grant? 203.53 Section 203.53 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR MINERALS REVENUE MANAGEMENT RELIEF OR REDUCTION IN ROYALTY RATES OCS Oil, Gas, and Sulfur General Royalty Relief for End-Of...

21 CFR 358.310 - Ingrown toenail relief active ingredient.

Code of Federal Regulations, 2011 CFR

2011-04-01

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Code of Federal Regulations, 2010 CFR

2010-04-01

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Code of Federal Regulations, 2013 CFR

2013-04-01

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Code of Federal Regulations, 2012 CFR

2012-04-01

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Code of Federal Regulations, 2014 CFR

2014-04-01

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The Effects of the Pauli Exclusion Principle in Determining the Ionization Energies of the Helium Atom and Helium-Like Ions

ERIC Educational Resources Information Center

Deeney, F. A.; O'Leary, J. P.

2012-01-01

For helium and helium-like ions, we have examined the differences between the values of the ionization energies as calculated from the Bohr theory and those measured in experiments. We find that these differences vary linearly with the atomic number of the system. Using this result, we show how the Bohr model for single-electron systems may be…

Acquisition system testing with superfluid helium. [cryopumping for space

NASA Technical Reports Server (NTRS)

Anderson, John E.; Fester, Dale A.; Dipirro, Michael J.

1988-01-01

Minus one-g outflow tests were conducted with superfluid helium in conjunction with a thermomechanical pump setup in order to study the use of capillary acquisition systems for NASA's Superfluid Helium On-Orbit Transfer (SHOOT) flight experiment. Results show that both fine mesh screen and porous sponge systems are capable of supplying superfluid helium to the thermomechanical pump inlet against a one-g head up to 4 cm, fulfilling the SHOOT requirements. Sponge results were found to be reproducible, while the screen results were not.

LOX, GOX and Pressure Relief

NASA Technical Reports Server (NTRS)

McLeod, Ken; Stoltzfus, Joel

2006-01-01

Oxygen relief systems present a serious fire hazard risk with often severe consequences. This presentation offers a risk management solution strategy which encourages minimizing ignition hazards, maximizing best materials, and utilizing good practices. Additionally, the relief system should be designed for cleanability and ballistic flow. The use of the right metals, softgoods, and lubricants, along with the best assembly techniques, is stressed. Materials should also be tested if data is not available and a full hazard analysis should be conducted in an effort to minimize risk and harm.

Applications of Groundwater Helium

USGS Publications Warehouse

Kulongoski, Justin T.; Hilton, David R.

2011-01-01

Helium abundance and isotope variations have widespread application in groundwater-related studies. This stems from the inert nature of this noble gas and the fact that its two isotopes ? helium-3 and helium-4 ? have distinct origins and vary widely in different terrestrial reservoirs. These attributes allow He concentrations and 3He/4He isotope ratios to be used to recognize and quantify the influence of a number of potential contributors to the total He budget of a groundwater sample. These are atmospheric components, such as air-equilibrated and air-entrained He, as well as terrigenic components, including in situ (aquifer) He, deep crustal and/or mantle He and tritiogenic 3He. Each of these components can be exploited to reveal information on a number of topics, from groundwater chronology, through degassing of the Earth?s crust to the role of faults in the transfer of mantle-derived volatiles to the surface. In this review, we present a guide to how groundwater He is collected from aquifer systems and quantitatively measured in the laboratory. We then illustrate the approach of resolving the measured He characteristics into its component structures using assumptions of endmember compositions. This is followed by a discussion of the application of groundwater He to the types of topics mentioned above using case studies from aquifers in California and Australia. Finally, we present possible future research directions involving dissolved He in groundwater.

Digital Shaded-Relief Image of Alaska

USGS Publications Warehouse

Riehle, J.R.; Fleming, Michael D.; Molnia, B.F.; Dover, J.H.; Kelley, J.S.; Miller, M.L.; Nokleberg, W.J.; Plafker, George; Till, A.B.

1997-01-01

Introduction One of the most spectacular physiographic images of the conterminous United States, and the first to have been produced digitally, is that by Thelin and Pike (USGS I-2206, 1991). The image is remarkable for its crispness of detail and for the natural appearance of the artificial land surface. Our goal has been to produce a shaded-relief image of Alaska that has the same look and feel as the Thelin and Pike image. The Alaskan image could have been produced at the same scale as its lower 48 counterpart (1:3,500,000). But by insetting the Aleutian Islands into the Gulf of Alaska, we were able to print the Alaska map at a larger scale (1:2,500,000) and about the same physical size as the Thelin and Pike image. Benefits of the 1:2,500,000 scale are (1) greater resolution of topographic features and (2) ease of reference to the U.S. Geological Survey (USGS) (1987) Alaska Map E and the statewide geologic map (Beikman, 1980), which are both 1:2,500,000 scale. Manually drawn, shaded-relief images of Alaska's land surface have long been available (for example, Department of the Interior, 1909; Raisz, 1948). The topography depicted on these early maps is mainly schematic. Maps showing topographic contours were first available for the entire State in 1953 (USGS, 1:250,000) (J.H. Wittmann, USGS, written commun., 1996). The Alaska Map E was initially released in 1954 in both planimetric (revised in 1973 and 1987) and shaded-relief versions (revised in 1973, 1987, and 1996); topography depicted on the shaded-relief version is based on the 1:250,000-scale USGS topographic maps. Alaska Map E was later modified to include hypsometric tinting by Raven Maps and Images (1989, revised 1993) as copyrighted versions. Other shaded-relief images were produced for The National Geographic Magazine (LaGorce, 1956; 1:3,000,000) or drawn by Harrison (1970; 1:7,500,000) for The National Atlas of the United States. Recently, the State of Alaska digitally produced a shaded-relief image

Seesaw at Lhc Through Left-Right Symmetry

NASA Astrophysics Data System (ADS)

Senjanović, Goran

I argue that LHC may shed light on the nature of neutrino mass through the probe of the seesaw mechanism. The smoking gun signature is lepton number violation through the production of same sign lepton pairs, a collider analogy of the neutrinoless double beta decay. I discuss this in the context of left-right symmetric theories, which led originally to neutrino mass and the seesaw mechanism. A WR gauge boson with a mass in a few TeV region could easily dominate neutrinoless double beta decay, and its discovery at LHC would have spectacular signatures of parity restoration and lepton number violation. Moreover, LHC can measure the masses of the right-handed neutrinos and the right-handed leptonic mixing matrix, which could in turn be used to predict the rates for neutrinoless double decay and lepton flavor violating violating processes. The LR scale at the LHC energies offers great hope of observing these low energy processes in the present and upcoming experiments.

Stepping outside the neighborhood of T at LHC

NASA Astrophysics Data System (ADS)

Wiedemann, Urs Achim

2009-11-01

“ As you are well aware, many in the RHIC community are interested in the LHC heavy-ion program, but have several questions: What can we learn at the LHC that is qualitatively new? Are collisions at LHC similar to RHIC ones, just with a somewhat hotter/denser initial state? If not, why not? These questions are asked in good faith, and this talk is an opportunity to answer them directly to much of the RHIC community.” With these words, the organizers of Quark Matter 2009 in Knoxville invited me to discuss the physics opportunities for heavy ion collisions at the LHC without recalling the standard arguments, which are mainly based on the extended kinematic reach of the machine. In response, I emphasize here that lattice QCD indicates characteristic qualitative differences between thermal physics in the neighborhood of the critical temperature (T400-500MeV), for which the relevant energy densities will be solely attainable at the LHC.

Helium on Venus - Implications for uranium and thorium

NASA Technical Reports Server (NTRS)

Prather, M. J.; Mcelroy, M. B.

1983-01-01

Helium is removed at an average rate of 10 to the 6th atoms per square centimeter per second from Venus's atmosphere by the solar wind following ionization above the plasmapause. The surface source of helium-4 on Venus is similar to that on earth, suggesting comparable abundances of crustal uranium and thorium.

Production of stoponium at the LHC

NASA Astrophysics Data System (ADS)

Kim, Chul; Idilbi, Ahmad; Mehen, Thomas; Yoon, Yeo Woong

2014-04-01

Although the Large Hadron Collider (LHC) has not observed supersymmetric (SUSY) partners of the Standard Model particles, their existence is not ruled out yet. One recently explored scenario in which there are light SUSY partners that have evaded current bounds from the LHC is that of a light long-lived stop quark. In this paper we consider light stop pair production at the LHC when the stop mass is between 200 and 400 GeV. If the stops are long-lived they can form a bound state, stoponium, which then undergoes two-body decays to Standard Model particles. By considering the near-threshold production of such a pair through the gluon-gluon fusion process and taking into account the strong Coulombic interactions responsible for the formation of this bound state, we obtain factorization theorems for the stop pair inclusive and differential production cross sections. We also perform a resummation of large threshold logarithms up to next-to-next-to-leading logarithmic accuracy using well-established renormalization group equations in an effective field theory methodology. These results are used to calculate the invariant mass distributions of two photons or two Z bosons coming from the decay of the stoponium at the LHC. For our choices of SUSY model parameters, the stoponium is not detectable above Standard Model backgrounds in γγ or ZZ at 8 TeV, but will be visible with 400 fb-1 of accumulated data if its mass is below 500 GeV when the LHC runs at 14 TeV.

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2011 CFR

2011-10-01

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46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2010 CFR

2010-10-01

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46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2014 CFR

2014-10-01

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46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2012 CFR

2012-10-01

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46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2013 CFR

2013-10-01

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Statistical Performance Evaluation Of Soft Seat Pressure Relief Valves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Stephen P.; Gross, Robert E.

2013-03-26

Risk-based inspection methods enable estimation of the probability of failure on demand for spring-operated pressure relief valves at the United States Department of Energy's Savannah River Site in Aiken, South Carolina. This paper presents a statistical performance evaluation of soft seat spring operated pressure relief valves. These pressure relief valves are typically smaller and of lower cost than hard seat (metal to metal) pressure relief valves and can provide substantial cost savings in fluid service applications (air, gas, liquid, and steam) providing that probability of failure on demand (the probability that the pressure relief valve fails to perform its intendedmore » safety function during a potentially dangerous over pressurization) is at least as good as that for hard seat valves. The research in this paper shows that the proportion of soft seat spring operated pressure relief valves failing is the same or less than that of hard seat valves, and that for failed valves, soft seat valves typically have failure ratios of proof test pressure to set pressure less than that of hard seat valves.« less

Energetic helium particles trapped in the magnetosphere

NASA Technical Reports Server (NTRS)

Chen, Jiasheng; Guzik, T. Gregory; Sang, Yeming; Wefel, John P.; Cooper, John F.

1994-01-01

High energy (approximately 40-100 MeV/nucleon) geomagnetically trapped helium nuclei have been measured, for the first time, by the ONR-604 instrument during the 1990/1991 Combined Release and Radiation Effects Satellite (CRRES) mission. The helium events observed at L less than 2.3 have a pitch angle distribution peaking perpendicular to the local magnetic field and are contained in peaks located at L = 1.2 and 1.9. The events in each peak can be characterized by power law energy spectra with indices of 10.0 +/- 0.7 for L = 1.9-2.3 and 6.8 +/- 1.0 for L = 1.15-1.3, before the large storm of 24 March 1991. CRRES was active during solar maximum when the anomalous component is excluded from the inner heliosphere, making it unlikely that the observed events derived from the anomalous component. The trapped helium counting rates decrease gradually with time indicating that these high energy ions were not injected by flares during the 1990/91 mission. Flare injection prior to mid-1990 may account for the highest energy particles, while solar wind injection during magnetic storms and subsequent acceleration could account for the helium at lower energies.

Further results related to the turbulent boundary layer with slot injection of helium

NASA Technical Reports Server (NTRS)

Larue, J. C.; Libby, P. A.

1978-01-01

Data from an experiment involving the slot injection of helium into a turbulent boundary layer in air are analyzed in terms of unconditioned and conditioned Favre-averages. The conditioning is based on two levels of helium concentration so that the contributions to the unconditioned statistics from air, helium, and mixture of these two gases can be determined. The distributions of intermittency associated with the two helium levels establish the domains of influence of air, helium, and mixture.

The PDF4LHC report on PDFs and LHC data: Results from Run I and preparation for Run II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rojo, Juan; Accardi, Alberto; Ball, Richard D.

2015-09-16

The accurate determination of Parton Distribution Functions (PDFs) of the proton is an essential ingredient of the Large Hadron Collider (LHC) program. PDF uncertainties impact a wide range of processes, from Higgs boson characterization and precision Standard Model measurements to New Physics searches. A major recent development in modern PDF analyses has been to exploit the wealth of new information contained in precision measurements from the LHC Run I, as well as progress in tools and methods to include these data in PDF fits. In this report we summarize the information that PDF-sensitive measurements at the LHC have provided somore » far, and review the prospects for further constraining PDFs with data from the recently started Run II. As a result, this document aims to provide useful input to the LHC collaborations to prioritize their PDF-sensitive measurements at Run II, as well as a comprehensive reference for the PDF-fitting collaborations.« less

The Large Hadron Collider (LHC): The Energy Frontier

NASA Astrophysics Data System (ADS)

Brianti, Giorgio; Jenni, Peter

The following sections are included: * Introduction * Superconducting Magnets: Powerful, Precise, Plentiful * LHC Cryogenics: Quantum Fluids at Work * Current Leads: High Temperature Superconductors to the Fore * A Pumping Vacuum Chamber: Ultimate Simplicity * Vertex Detectors at LHC: In Search of Beauty * Large Silicon Trackers: Fast, Precise, Efficient * Two Approaches to High Resolution Electromagnetic Calorimetry * Multigap Resistive Plate Chamber: Chronometry of Particles * The LHCb RICH: The Lord of the Cherenkov Rings * Signal Processing: Taming the LHC Data Avalanche * Giant Magnets for Giant Detectors

Acoustic properties of supersonic helium/air jets at low Reynolds numbers

NASA Technical Reports Server (NTRS)

Mclaughlin, Dennis K.; Barron, W. D.; Vaddempudi, Appa R.

1992-01-01

Experiments have been performed with the objective of developing a greater understanding of the physics of hot supersonic jet noise. Cold helium/air jets are used to easily and inexpensively simulate the low densities of hot air jets. The experiments are conducted at low Reynolds numbers in order to facilitate study of the large-scale turbulent structures (instability waves) that cause most of the radiated noise. Experiments have been performed on Mach 1.5 and 2.1 jets of pure air, pure helium and 10 percent helium by mass. Helium/air jets are shown to radiate more noise than pure air jets due to the increased exit velocity. Microphone spectra are usually dominated by a single spectral component at a predictable frequency. Increasing the jet's helium concentration is shown to increase the dominant frequency. The helium concentration in the test chamber is determined by calculating the speed of sound from the measured phase difference between two microphone signals. Bleeding outside air into the test chamber controls the accumulation of helium so that the hot jet simulation remains valid. The measured variation in the peak radiated noise frequency is in good agreement with the predictions of the hot jet noise theory of Tam et al.

Testing the Interstellar Wind Helium Flow Direction with Galileo Euvs Data

NASA Astrophysics Data System (ADS)

Pryor, W. R.; Simmons, K. E.; Ajello, J. M.; Tobiska, W. K.; Retherford, K. D.; Stern, S. A.; Feldman, P. D.; Frisch, P. C.; Bzowski, M.; Grava, C.

2014-12-01

Forty years of measurements of the flow of interstellar helium through the heliosphere suggest that variations of the flow direction with time are possible. We will model Galileo Extreme Ultraviolet Spectrometer (EUVS) data to determine the best-fitting flow direction and compare it to values obtained by other spacecraft. The Galileo EUVS (Hord et al., 1992) was mounted on the spinning part of the spacecraft and obtained interstellar wind hydrogen Lyman-alpha 121.6 nm and helium 58.4 nm data on great circles passing near the ecliptic poles during the interplanetary cruise phase of the mission and also during the Jupiter orbital phase of the mission. The Galileo hydrogen cruise data have been previously published (Hord et al., 1991, Pryor et al., 1992; 1996; 2001), but the helium data have not. Our model was previously used by Ajello et al., 1978, 1979 to model Mariner 10 interstellar wind helium data, and by Stern et al., 2012 and Feldman et al., 2012 to model the interplanetary helium background near the moon in Lunar Reconnaissance Orbiter (LRO) Lyman-alpha Mapping Project (LAMP) data. The model has been updated to include recent determinations of daily helium 58.4 nm solar flux variations and helium losses due to EUV photoionization and electron impact ionization.

Production of carbon monoxide-free hydrogen and helium from a high-purity source

DOEpatents

Golden, Timothy Christopher [Allentown, PA; Farris, Thomas Stephen [Bethlehem, PA

2008-11-18

The invention provides vacuum swing adsorption processes that produce an essentially carbon monoxide-free hydrogen or helium gas stream from, respectively, a high-purity (e.g., pipeline grade) hydrogen or helium gas stream using one or two adsorber beds. By using physical adsorbents with high heats of nitrogen adsorption, intermediate heats of carbon monoxide adsorption, and low heats of hydrogen and helium adsorption, and by using vacuum purging and high feed stream pressures (e.g., pressures of as high as around 1,000 bar), pipeline grade hydrogen or helium can purified to produce essentially carbon monoxide -free hydrogen and helium, or carbon monoxide, nitrogen, and methane-free hydrogen and helium.

Helium diffusion parameters of hematite from a single-diffusion-domain crystal

NASA Astrophysics Data System (ADS)

Farley, K. A.

2018-06-01

This contribution reports new parameters for helium diffusion in hematite useful for interpretation of cosmogenic 3He and radiogenic 4He chronometry. Fragments of a coarse, euhedral single crystal of hematite from Minas Gerais, Brazil were subjected to bulk step-heating helium diffusion experiments after proton irradiation to make a uniform distribution of 3He. Aliquots of three different grain sizes ranging from ∼300 to ∼700 μm in equivalent-sphere radius yielded helium diffusion activation energies Ea ∼ 170 kJ/mol, very similar to previous estimates for Ea in hematite. Uniquely in this specimen, diffusivity varies with the dimensions of the analyzed fragments in precisely the fashion expected if the diffusion domain corresponds to the physical grain. This contrasts with previous studies that concluded that the analyzed hematites consist of polycrystalline aggregates in which helium migration is governed by the size distribution of the constituent crystallites. These new data permit a direct estimate of the helium diffusivity at infinite temperature for hematite of ln(Do) = -0.66 ± 0.35 in cm2/s. The major implication of the new diffusion parameters is that hematite is very retentive of helium even at very small crystal sizes. For example, a 20 nm radius hematite crystal, at the smallest end of the size range so far described in dated polycrystalline hematite specimens, will retain more than 99% of its ingrown He over 1 Myr at 30 °C, and more than 90% over 100 Myr. Under most conditions, hematite is close to quantitatively helium-retentive on the Earth's surface, simplifying radiogenic and cosmogenic helium dating of this phase. In a system cooling at 10 °C/Myr, the 20 nm hematite crystal has a He closure temperature of ∼70 °C, similar to a typical ∼100 μm apatite crystal. Helium is likely held tightly in hematite owing to its dense hexagonal closest packing structure and absence of migration-enhancing channels. The isostructural minerals corundum

r-process nucleosynthesis in dynamic helium-burning environments

NASA Technical Reports Server (NTRS)

Cowan, J. J.; Cameron, A. G. W.; Truran, J. W.

1985-01-01

The results of an extended examination of r-process nucleosynthesis in helium-burning enviroments are presented. Using newly calculated nuclear rates, dynamical r-process calculations have been made of thermal runaways in helium cores typical of low-mass stars and in the helium zones of stars undergoing supernova explosions. These calculations show that, for a sufficient flux of neutrons produced by the C-13 neutron source, r-process nuclei in solar proportions can be produced. The conditions required for r-process production are found to be 10 to the 20th-10 to the 21st neutrons per cubic centimeter for times of 0.01-0.1 s and neutron number densities in excess of 10 to the 19th per cubic centimeter for times of about 1 s. The amount of C-13 required is found to be exceedingly high - larger than is found to occur in any current stellar evolutionary model. It is thus unlikely that these helium-burning environments are responsible for producing the bulk of the r-process elements seen in the solar system.

Photovoltaic application for disaster relief

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, W.R. Jr.

1995-11-01

Hurricanes, floods, tornados, and earthquakes are natural disasters that can happen at any time destroying homes, businesses, and natural surroundings. One such disaster, Hurricane Andrew, devastated South Florida leaving several hundred-thousand people homeless. Many people were without electrical service, functioning water and sewage systems, communications, and medical services for days, even weeks in the aftermath of the storm. Emergency management teams, the military, and countless public and private organizations staged a massive relief effort. Dependency on electrical utility power became a pronounced problem as emergency services were rendered to survivors and the rebuilding process started. Many of the energy needsmore » of emergency management organizations, relief workers, and the general public can be satisfied with solar electric energy systems. Photovoltaic (PV) power generated from solar energy is quiet, safe, inexhaustible and pollution-free. Previously, photovoltaics have supplied emergency power for Hurricanes Hugo and Andrew, and the earthquake at Northridge in Southern California. This document focuses on photovoltaic technology and its application to disaster relief efforts.« less

48 CFR 252.229-7001 - Tax relief.

Code of Federal Regulations, 2011 CFR

2011-10-01

... following paragraph (d) to the basic clause: (d) Tax relief will be claimed in Germany pursuant to the provisions of the Agreement Between the United States of America and Germany Concerning Tax Relief to be Accorded by Germany to United States Expenditures in the Interest of Common Defense. The Contractor shall...

48 CFR 252.229-7001 - Tax relief.

Code of Federal Regulations, 2010 CFR

2010-10-01

... following paragraph (d) to the basic clause: (d) Tax relief will be claimed in Germany pursuant to the provisions of the Agreement Between the United States of America and Germany Concerning Tax Relief to be Accorded by Germany to United States Expenditures in the Interest of Common Defense. The Contractor shall...

48 CFR 252.229-7001 - Tax relief.

Code of Federal Regulations, 2012 CFR

2012-10-01

... following paragraph (d) to the basic clause: (d) Tax relief will be claimed in Germany pursuant to the provisions of the Agreement Between the United States of America and Germany Concerning Tax Relief to be Accorded by Germany to United States Expenditures in the Interest of Common Defense. The Contractor shall...

48 CFR 252.229-7001 - Tax relief.

Code of Federal Regulations, 2013 CFR

2013-10-01

... following paragraph (d) to the basic clause: (d) Tax relief will be claimed in Germany pursuant to the provisions of the Agreement Between the United States of America and Germany Concerning Tax Relief to be Accorded by Germany to United States Expenditures in the Interest of Common Defense. The Contractor shall...

LHC magnet quench protection system

NASA Astrophysics Data System (ADS)

Coull, L.; Hagedorn, D.; Remondino, V.; Rodriguez-Mateos, F.

1994-07-01

The quench protection system for the superconducting magnets of the CERN Large Hadron Collider (LHC) is described. The system is based on the so called 'cold diode' concept. In a group of series connected magnets if one magnet quenches then the magnetic energy of all the magnets will be dissipated in the quenched magnet so destroying it. This is avoided by by-passing the quenched magnet and then rapidly de-exciting the unquenched magnets. For the LHC machine it is foreseen to use silicon diodes situated inside the cryostat as by-pass elements - so called 'cold diodes'. The diodes are exposed to some 50 kGray of radiation during a 10 year operation life-time. The high energy density of the LHC magnets (500 kJ/m) coupled with the relatively slow propagation speed of a 'natural' quench (10 to 20 m/s) can lead to excessive heating of the zone where the quench started and to high internal voltages. It is therefore necessary to detect quickly the incipient quench and fire strip heaters which spread the quench out more quickly over a large volume of the magnet. After a quench the magnet chain must be de-excited rapidly to avoid spreading the quench to other magnets and over-heating the by-pass diode. This is done by switching high-power energy-dump resistors in series with the magnets. The LHC main ring magnet will be divided into 16 electrically separated units which has important advantages.

Commissioning of the JT-60SA helium refrigerator

NASA Astrophysics Data System (ADS)

Kamiya, Koji; Natsume, Kyohei; Ohtsu, Kiichi; Oishi, Makoto; Honda, Atsushi; Kashiwa, Yoshitoshi; Kizu, Kaname; Koide, Yoshihiko; Hoa, Christine; Michel, Frederic; Roussel, Pascal; Lamaison, Valerie; Bonne, Francois; Dipietro, Enrico; Cardella, Antonino; Wanner, Manfred; Legrand, Jerome; Pudys, Vincent; Langevin, Baptiste

2017-09-01

The JT-60SA project will use superconducting magnets to confine the plasma and achieve a plasma current with a typical flat top duration of 100 second in purely inductive mode. The helium refrigerator has an equivalent cooling power of 9 kW at 4.5 K providing 3.7 K, 4.5 K, 50 K and 80 K for the diverter cryopump, the superconducting magnets, the HTS current leads, and the thermal shields, respectively. This paper summarizes the JT-60SA helium refrigerator commissioning activities aiming at successful operation of heat load smoothing technology to manage the 12 kW heat pulses by 9 kW cooling power using a 7000 liter liquid helium.

Helium diffusion in carbonates

NASA Astrophysics Data System (ADS)

Amidon, W. H.; Cherniak, D. J.; Watson, E. B.; Hobbs, D.

2013-12-01

The abundance and large grain size of carbonate minerals make them a potentially attractive target for 4He thermochronology and 3He cosmogenic dating, although the diffusive properties of helium in carbonates remain poorly understood. This work characterizes helium diffusion in calcite and dolomite to better understand the crystal-chemical factors controlling He transport and retentivity. Slabs of cleaved natural calcite and dolomite, and polished sections of calcite cut parallel or normal to c, were implanted with 3He at 3 MeV with a dose of 5x1015/cm2. Implanted carbonates were heated in 1-atm furnaces, and 3He distributions following diffusion anneals were profiled with Nuclear Reaction Analysis using the reaction 3He(d,p)4He. For 3He transport normal to cleavage surfaces in calcite, we obtain the following Arrhenius relation over the temperature range 78-300°C: Dcalcite = 9.0x10-9exp(-55 × 6 kJ mol-1/RT) m2sec-1. Diffusion in calcite exhibits marked anisotropy, with diffusion parallel to c about two orders of magnitude slower than diffusion normal to cleavage faces. He diffusivities for transport normal to the c-axis are similar in value to those normal to cleavage surfaces. Our findings are broadly consistent with helium diffusivities from step-heating measurements of calcite by Copeland et al. (2007); these bulk degassing data may reflect varying effects of diffusional anisotropy. Helium diffusion normal to cleavage surfaces in dolomite is significantly slower than diffusion in calcite, and has a much higher activation energy for diffusion. For dolomite, we obtain the following Arrhenius relation for He diffusion over the temperature range 150-400°C: Ddolomite = 9.0x10-8exp(-92 × 9 kJ mol-1/RT) m2sec-1. The role of crystallographic structure in influencing these differences among diffusivities was evaluated using the maximum aperture approach of Cherniak and Watson (2011), in which crystallographic structures are sectioned along possible diffusion

Pain relief at the end of life: nurses' experiences regarding end-of-life pain relief in patients with dementia.

PubMed

Brorson, Hanna; Plymoth, Henrietta; Örmon, Karin; Bolmsjö, Ingrid

2014-03-01

Patients with dementia receive suboptimal palliative care, and this patient group is at risk to have pain at the end of life. Because communicative impairments are common in this patient group, nurses play an important caregiver role in identifying, assessing, and relieving patients' pain. This study aimed to describe nurses' experiences regarding end-of-life pain relief in patients with dementia. This descriptive exploratory qualitative study was based on seven semistructured interviews. Burnard's content analysis inspired the data analysis. Two main categories were identified: (1) nurses' experience of difficulties concerning pain relief and (2) nurses' experience of resources concerning pain relief. Nurses experienced difficulties, such as feeling of powerlessness because of difficulties in obtaining adequate prescriptions for analgesics, ethical dilemmas, feeling of inadequacy because analgesia did not have the desired effect, and a feeling of not being able to connect with the patient. Factors, including knowledge about the patient, professional experience, utilization of pain assessment tools, interpersonal relationships, and interprofessional cooperation, served as resources and enabled end-of-life pain relief. The results of this study highlight the complexity of pain relief in patients with dementia at the end of life from a nursing perspective. The inability of patients with dementia to verbally communicate their pain makes them a vulnerable patient group, dependent on their caregivers. Knowing the life story of the patient, professional experience, teamwork based on good communication, and use of a pain assessment tool were reported by the nurses to improve pain relief at the end of life for patients with dementia. Copyright © 2014 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

30 CFR 204.201 - Who may obtain accounting and auditing relief?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Who may obtain accounting and auditing relief... MINERALS REVENUE MANAGEMENT ALTERNATIVES FOR MARGINAL PROPERTIES Accounting and Auditing Relief § 204.201 Who may obtain accounting and auditing relief? (a) You may obtain accounting and auditing relief under...

Long-term variations of fluxes of solar protons and helium isotopes

NASA Astrophysics Data System (ADS)

Anufriev, G. S.

2012-11-01

The fluxes of hydrogen and helium isotopes in the solar wind are reconstructed over a long time scale since the present time up to 600 million years back. Abundances of helium isotopes, obtained in the helium isotopic analysis made for 8 lunar soil samples, were used as initial data in the reconstruction procedure. Samples were taken off from various levels of the 1.6-m core of lunar soil delivered by the automatic Luna-24 station in 1976. The data on modern hydrogen and helium fluxes were used as well. The developed reconstruction procedure allowed one to select various solar wind components in a "gross" composition. Proton flux variations over the interval of 600 million years do not exceed a value of 40 %. Helium flux variations reach a value of 1.5-2 relative to the average value. Most likely, this circumstance is caused by considerable variations of a number of coronal mass ejections ( CME) enriched by helium. The arguments in favor of solar activity polycyclicity on a long time scale are discussed.

Evolution Models of Helium White Dwarf–Main-sequence Star Merger Remnants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Xianfei; Bi, Shaolan; Hall, Philip D.

It is predicted that orbital decay by gravitational-wave radiation and tidal interaction will cause some close binary stars to merge within a Hubble time. The merger of a helium-core white dwarf with a main-sequence (MS) star can produce a red giant branch star that has a low-mass hydrogen envelope when helium is ignited and thus become a hot subdwarf. Because detailed calculations have not been made, we compute post-merger models with a stellar evolution code. We find the evolutionary paths available to merger remnants and find the pre-merger conditions that lead to the formation of hot subdwarfs. We find thatmore » some such mergers result in the formation of stars with intermediate helium-rich surfaces. These stars later develop helium-poor surfaces owing to diffusion. Combining our results with a model population and comparing to observed stars, we find that some observed intermediate helium-rich hot subdwarfs can be explained as the remnants of the mergers of helium-core white dwarfs with low-mass MS stars.« less

L'Aventure du LHC

ScienceCinema

None

2018-05-16

Cette présentation s’adressera principalement aux personnes qui ont construit le LHC. La construction du LHC fut longue et difficile. De nombreux problèmes sont apparus en cours de route. Tous ont été résolus grâce au dévouement et à l’engagement du personnel et des collaborateurs. Je reviendrai sur les coups durs et les réussites qui ont marqués ces 15 dernières années et je vous montrerai combien cette machine, le fruit de vos efforts, est extraordinaire.

Fast resolution change in neutral helium atom microscopy

NASA Astrophysics Data System (ADS)

Flatabø, R.; Eder, S. D.; Ravn, A. K.; Samelin, B.; Greve, M. M.; Reisinger, T.; Holst, B.

2018-05-01

In neutral helium atom microscopy, a beam of atoms is scanned across a surface. Though still in its infancy, neutral helium microscopy has seen a rapid development over the last few years. The inertness and low energy of the helium atoms (less than 0.1 eV) combined with a very large depth of field and the fact that the helium atoms do not penetrate any solid material at low energies open the possibility for a non-destructive instrument that can measure topology on the nanoscale even on fragile and insulating surfaces. The resolution is determined by the beam spot size on the sample. Fast resolution change is an attractive property of a microscope because it allows different aspects of a sample to be investigated and makes it easier to identify specific features. However up till now it has not been possible to change the resolution of a helium microscope without breaking the vacuum and changing parts of the atom source. Here we present a modified source design, which allows fast, step wise resolution change. The basic design idea is to insert a moveable holder with a series of collimating apertures in front of the source, thus changing the effective source size of the beam and thereby the spot size on the surface and thus the microscope resolution. We demonstrate a design with 3 resolution steps. The number of resolution steps can easily be extended.

Formation of Triplet Positron-helium Bound State by Stripping of Positronium Atoms in Collision with Ground State Helium

NASA Technical Reports Server (NTRS)

Drachman, Richard J.

2006-01-01

Formation of triplet positron-helium bound state by stripping of positronium atoms in collision with ground state helium JOSEPH DI RlENZI, College of Notre Dame of Maryland, RICHARD J. DRACHMAN, NASA/Goddard Space Flight Center - The system consisting of a positron and a helium atom in the triplet state e(+)He(S-3)(sup e) was conjectured long ago to be stable [1]. Its stability has recently been established rigorously [2], and the values of the energies of dissociation into the ground states of Ps and He(+) have also been reported [3] and [4]. We have evaluated the cross-section for this system formed by radiative attachment of a positron in triplet He state and found it to be small [5]. The mechanism of production suggested here should result in a larger cross-section (of atomic size) which we are determining using the Born approximation with simplified initial and final wave functions.

Theoretical and experimental investigation of magnetic field related helium leak in helium vessel of a large superconducting magnet

NASA Astrophysics Data System (ADS)

Bhattachryya, Pranab; Gupta, Anjan Dutta; Dhar, S.; Sarma, P. R.; Mukherjee, Paramita

2017-06-01

The helium vessel of the superconducting cyclotron (SCC) at the Variable Energy Cyclotron centre (VECC), Kolkata shows a gradual loss of insulation vacuum from 10-7 mbar to 10-4 mbar with increasing coil current in the magnet. The insulation vacuum restores back to its initial value with the withdrawal of current. The origin of such behavior has been thought to be related to the electromagnetic stress in the magnet. The electromagnetic stress distribution in the median plane of the helium vessel was studied to figure out the possible location of the helium leak. The stress field from the possible location was transferred to a simplified 2D model with different leak geometries to study the changes in conductance with coil current. The leak rate calculated from the changes in the leak geometry was compared with the leak rate calculated from the experimental insulation vacuum degradation behavior to estimate the initial leak shape and size.

46 CFR 54.30-10 - Method of performing mechanical stress relief.

Code of Federal Regulations, 2011 CFR

2011-10-01

... PRESSURE VESSELS Mechanical Stress Relief § 54.30-10 Method of performing mechanical stress relief. (a) The mechanical stress relief shall be carried out in accordance with the following stipulations using water as... 46 Shipping 2 2011-10-01 2011-10-01 false Method of performing mechanical stress relief. 54.30-10...

46 CFR 54.30-10 - Method of performing mechanical stress relief.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Method of performing mechanical stress relief. 54.30-10... PRESSURE VESSELS Mechanical Stress Relief § 54.30-10 Method of performing mechanical stress relief. (a) The mechanical stress relief shall be carried out in accordance with the following stipulations using water as...

46 CFR 54.30-10 - Method of performing mechanical stress relief.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Method of performing mechanical stress relief. 54.30-10... PRESSURE VESSELS Mechanical Stress Relief § 54.30-10 Method of performing mechanical stress relief. (a) The mechanical stress relief shall be carried out in accordance with the following stipulations using water as...

46 CFR 54.30-10 - Method of performing mechanical stress relief.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Method of performing mechanical stress relief. 54.30-10... PRESSURE VESSELS Mechanical Stress Relief § 54.30-10 Method of performing mechanical stress relief. (a) The mechanical stress relief shall be carried out in accordance with the following stipulations using water as...

46 CFR 54.30-10 - Method of performing mechanical stress relief.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Method of performing mechanical stress relief. 54.30-10... PRESSURE VESSELS Mechanical Stress Relief § 54.30-10 Method of performing mechanical stress relief. (a) The mechanical stress relief shall be carried out in accordance with the following stipulations using water as...

Applying Chemical Potential and Partial Pressure Concepts to Understand the Spontaneous Mixing of Helium and Air in a Helium-Inflated Balloon

ERIC Educational Resources Information Center

Jee-Yon Lee; Hee-Soo Yoo; Jong Sook Park; Kwang-Jin Hwang; Jin Seog Kim

2005-01-01

The spontaneous mixing of helium and air in a helium-inflated balloon is described in an experiment in which the partial pressure of the gases in the balloon are determined from the mole factions and the total pressure measured in the balloon. The results described provide a model for teaching concepts of partial pressure, chemical potential, and…

Turning the LHC ring into a new physics search machine

NASA Astrophysics Data System (ADS)

Orava, Risto

2017-03-01

The LHC Collider Ring is proposed to be turned into an ultimate automatic search engine for new physics in four consecutive phases: (1) Searches for heavy particles produced in Central Exclusive Process (CEP): pp → p + X + p based on the existing Beam Loss Monitoring (BLM) system of the LHC; (2) Feasibility study of using the LHC Ring as a gravitation wave antenna; (3) Extensions to the current BLM system to facilitate precise registration of the selected CEP proton exit points from the LHC beam vacuum chamber; (4) Integration of the BLM based event tagging system together with the trigger/data acquisition systems of the LHC experiments to facilitate an on-line automatic search machine for the physics of tomorrow.

46 CFR 154.519 - Piping relief valves.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Process Piping Systems § 154.519 Piping relief valves. (a) The liquid relief valve that protects the cargo piping system from liquid pressure exceeding the design pressure must discharge into: (1) A cargo tank; or (2) A cargo vent mast if that vent mast has a means for the detection and removal of the liquid...

46 CFR 154.519 - Piping relief valves.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Process Piping Systems § 154.519 Piping relief valves. (a) The liquid relief valve that protects the cargo piping system from liquid pressure exceeding the design pressure must discharge into: (1) A cargo tank; or (2) A cargo vent mast if that vent mast has a means for the detection and removal of the liquid...

46 CFR 154.519 - Piping relief valves.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Process Piping Systems § 154.519 Piping relief valves. (a) The liquid relief valve that protects the cargo piping system from liquid pressure exceeding the design pressure must discharge into: (1) A cargo tank; or (2) A cargo vent mast if that vent mast has a means for the detection and removal of the liquid...

46 CFR 154.519 - Piping relief valves.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Process Piping Systems § 154.519 Piping relief valves. (a) The liquid relief valve that protects the cargo piping system from liquid pressure exceeding the design pressure must discharge into: (1) A cargo tank; or (2) A cargo vent mast if that vent mast has a means for the detection and removal of the liquid...

49 CFR 178.347-4 - Pressure relief.

Code of Federal Regulations, 2010 CFR

2010-10-01

... adequate vapor and liquid capacity to limit the tank pressure to the cargo tank test pressure at maximum... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Specifications for Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank...

46 CFR 154.801 - Pressure relief systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Pressure relief systems. 154.801 Section 154.801 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Vent Systems § 154.801 Pressure relief systems. (a) Each cargo tank that has a volume of 20m3 (706 ft.3...

Concept for a dark matter detector using liquid helium-4

NASA Astrophysics Data System (ADS)

Guo, W.; McKinsey, D. N.

2013-06-01

Direct searches for light dark matter particles (mass<10GeV) are especially challenging because of the low energies transferred in elastic scattering to typical heavy nuclear targets. We investigate the possibility of using liquid helium-4 as a target material, taking advantage of the favorable kinematic matching of the helium nucleus to light dark matter particles. Monte Carlo simulations are performed to calculate the charge, scintillation, and triplet helium molecule signals produced by recoil He ions, for a variety of energies and electric fields. We show that excellent background rejection might be achieved based on the ratios between different signal channels. The sensitivity of the helium-based detector to light dark matter particles is estimated for various electric fields and light collection efficiencies.

Mechanical Design of the LHC Standard Half-Cell

NASA Astrophysics Data System (ADS)

Poncet, A.; Brunet, J. C.; Cruikshank, P.; Genet, M.; Parma, V.; Rohmig, P.; Saban, R.; Tavian, L.; Veness, R.; Vlogaert, J.; Williams, L. R.

1997-05-01

The LHC Conceptual Design Report issued on 20th October 1995 (CERN/AC/95-05 (LHC) - nicknamed "Yellow Book") introduced significant changes to some fundamental features of the LHC standard half-cell, composed of one quadrupole, 3 dipoles and a set of corrector magnets. A separate cryogenic distribution line was introduced, which was previously inside the main cryostat. The dipole length has been increased from 10 to 15 m and independent powering of the focusing and defocusing quadrupole magnets was chosen. Individual quench protection diodes were introduced in magnets interconnects and many auxiliary bus bars were added to feed in series the various families of correcting superconducting magnets. The various highly intricate basic systems such as: cryostats and cryogenics feeders, superconducting magnets and their electrical feeding and protection, vacuum beam screen and its cooling, support and alignment devices have been redesigned, taking into account the very tight space available. These space constraints are given by the necessity to have maximum integral bending field strength for maximum LHC energy, and the existing LHC tunnel. Finally, cryogenic and vacuum sectorisation have been introduced to reduce downtimes and facilitate commissioning.

The local interstellar helium density - Corrected

NASA Technical Reports Server (NTRS)

Freeman, J.; Paresce, F.; Bowyer, S.

1979-01-01

An upper bound for the number density of neutral helium in the local interstellar medium of 0.004 + or - 0.0022 per cu cm was previously reported, based on extreme-ultraviolet telescope observations at 584 A made during the 1975 Apollo-Soyuz Test Project. A variety of evidence is found which indicates that the 584-A sensitivity of the instrument declined by a factor of 2 between the last laboratory calibration and the time of the measurements. The upper bound on the helium density is therefore revised to 0.0089 + or - 0.005 per cu cm.

High resolution spectroscopy of six new extreme helium stars

NASA Technical Reports Server (NTRS)

Heber, U.; Jones, G.; Drilling, J. S.

1986-01-01

High resolution spectra of six newly discovered extreme helium stars are presented. LSS 5121 is shown to be a spectroscopical twin of the hot extreme helium star HD 160641. A preliminary LTE analysis of LSS 3184 yielded an effective temperature of 22,000 K and a surface gravity of log g = 3.2. Four stars form a new subgroup, classified by sharp-lined He I spectra and pronounced O II spectra, and it is conjectured that these lie close to the Eddington limit. The whole group of extreme helium stars apparently is inhomogeneous with respect to luminosity to mass ratio and chemical composition.

Multi-objective Optimization on Helium Liquefier Using Genetic Algorithm

NASA Astrophysics Data System (ADS)

Wang, H. R.; Xiong, L. Y.; Peng, N.; Meng, Y. R.; Liu, L. Q.

2017-02-01

Research on optimization of helium liquefier is limited at home and abroad, and most of the optimization is single-objective based on Collins cycle. In this paper, a multi-objective optimization is conducted using genetic algorithm (GA) on the 40 L/h helium liquefier developed by Technical Institute of Physics and Chemistry of the Chinese Academy of Science (TIPC, CAS), steady solutions are obtained in the end. In addition, the exergy loss of the optimized system is studied in the case of with and without liquid nitrogen pre-cooling. The results have guiding significance for the future design of large helium liquefier.

Anomalous behavior of cristobalite in helium under high pressure

NASA Astrophysics Data System (ADS)

Sato, Tomoko; Takada, Hiroto; Yagi, Takehiko; Gotou, Hirotada; Okada, Taku; Wakabayashi, Daisuke; Funamori, Nobumasa

2013-01-01

We have investigated the high-pressure behavior of cristobalite in helium by powder X-ray diffraction. Cristobalite transformed to a new phase at about 8 GPa. This phase is supposed to have a molar volume of about 30 % larger than cristobalite, suggesting the dissolution of helium atoms in its interstitial voids. On further compression, the new phase transformed to a different phase which showed an X-ray diffraction pattern similar to cristobalite X-I at about 21 GPa. On the other hand, when the new phase was decompressed, it transformed to another new phase at about 7 GPa, which is also supposed to have a molar volume of about 25 % larger than cristobalite. On further decompression, the second new phase transformed to cristobalite II at about 2 GPa. In contrast to cristobalite, quartz did not show anomalous behavior in helium. The behavior of cristobalite in helium was also consistent with that in other mediums up to about 8 GPa, where the volume of cristobalite became close to that of quartz. These results suggest that dissolution of helium may be controlled not only by the density (amount of voids) but also by the network structure of SiO4 tetrahedra (topology of voids).

LHC forward physics

DOE PAGES

Akiba, K.; Akbiyik, M.; Albrow, M.; ...

2016-10-17

The goal of this report is to give a comprehensive overview of the rich field of forward physics, with a special attention to the topics that can be studied at the LHC. The report starts presenting a selection of the Monte Carlo simulation tools currently available, chapter 2, then enters the rich phenomenology of QCD at low, chapter 3, and high, chapter 4, momentum transfer, while the unique scattering conditions of central exclusive production are analyzed in chapter 5. The last two experimental topics, Cosmic Ray and Heavy Ion physics are presented in the chapter 6 and 7 respectively. Chaptermore » 8 is dedicated to the BFKL dynamics, multiparton interactions, and saturation. Here, the report ends with an overview of the forward detectors at LHC. Each chapter is correlated with a comprehensive bibliography, attempting to provide to the interested reader with a wide opportunity for further studies.« less

LHC forward physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cartiglia, N.; Royon, C.

The goal of this report is to give a comprehensive overview of the rich field of forward physics, with a special attention to the topics that can be studied at the LHC. The report starts presenting a selection of the Monte Carlo simulation tools currently available, chapter 2, then enters the rich phenomenology of QCD at low, chapter 3, and high, chapter 4, momentum transfer, while the unique scattering conditions of central exclusive production are analyzed in chapter 5. The last two experimental topics, Cosmic Ray and Heavy Ion physics are presented in the chapter 6 and 7 respectively. Chaptermore » 8 is dedicated to the BFKL dynamics, multiparton interactions, and saturation. The report ends with an overview of the forward detectors at LHC. Each chapter is correlated with a comprehensive bibliography, attempting to provide to the interested reader with a wide opportunity for further studies.« less

Superfluid helium quantum interference devices: physics and applications.

PubMed

Sato, Y; Packard, R E

2012-01-01

We present an overview of recent developments related to superfluid helium quantum interference devices (SHeQUIDs). We discuss the physics of two reservoirs of superfluid helium coupled together and describe the quantum oscillations that result from varying the coupling strength. We explain the principles behind SHeQUIDs that can be built based on these oscillations and review some techniques and applications.

Stopping-Power and Range Tables for Electrons, Protons, and Helium Ions

National Institute of Standards and Technology Data Gateway

SRD 124 NISStopping-Power and Range Tables for Electrons, Protons, and Helium Ions (Web, free access)   The databases ESTAR, PSTAR, and ASTAR calculate stopping-power and range tables for electrons, protons, or helium ions. Stopping-power and range tables can be calculated for electrons in any user-specified material and for protons and helium ions in 74 materials.

The Federal Helium supply: How we got here and where we might be going

NASA Astrophysics Data System (ADS)

Elsesser, Mark

2015-03-01

Helium is a limited, non-renewable resource with large uncertainties in both supply and price. It's essential for academic researchers across the physical sciences and engineering disciplines who depend on liquid helium to perform experiments and maintain critical instruments. However, because only about three percent of helium is used for scientific research, academic users have little leverage in the helium marketplace. With the Federal Helium Reserve required to sell off its remaining supply and close its doors within the next decade, many in academia are wondering ``what's next''? I will discuss the history of the Federal Helium Reserve, including legislation that shaped its development, and possibilities going forward. Additionally, I will describe a new APS initiative where we have formed a small consortium of academic liquid helium users and are allowing the Defense Logistics Agency to represent the consortium in liquid helium contract negotiations.

Performance of the Helium Circulation System on a Commercialized MEG

NASA Astrophysics Data System (ADS)

T, Takeda; M, Okamoto; T, Miyazaki; K, Katagiri

2012-12-01

We report the performance of a helium circulation system (HCS) mounted on a MEG (Magnetoencephalography) at Nagoya University, Japan. This instrument is the first commercialized version of an HCS. The HCS collects warm helium gas at approximately 300 K and then cools it to approximately 40 K. The gas is returned to the neck tube of a Dewar of the MEG to keep it cold. It also collects helium gas in the region just above the liquid helium surface while it is still cold, re-liquefies the gas and returns it to the Dewar. A special transfer tube (TT) of approximately 3 m length was developed to allow for dual helium streams. This tube separates the HCS using a MEG to reduce magnetic noise. A refiner was incorporated to effectively collect contaminating gases by freezing them. The refiner was equipped with an electric heater to remove the frozen contaminants as gases into the air. A gas flow controller was also developed, which automatically controlled the heater and electric valves to clean up contamination. The developed TT exhibited a very low heat inflow of less than 0.1 W/m to the liquid helium, ensuring efficient operation. The insert tube diameter, which was 1.5 in. was reduced to a standard 0.5 in. size. This dimensional change enabled the HCS to mount onto any commercialized MEG without any modifications to the MEG. The HCS can increase liquid helium in the Dewar by at least 3 liters/Day using two GM cryocoolers (SRDK-415D, Sumitomo Heavy Industries, Ltd.). The noise levels were virtually the same as before this installation.

Commissioning the cryogenic system of the first LHC sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Millet, F.; Claudet, S.; Ferlin, G.

2007-12-01

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 commissioningmore » 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.« less

The compressibility and the capacitance coefficient of helium-oxygen atmospheres.

PubMed

Imbert, G; Dejours, P; Hildwein, G

1982-12-01

The capacitance coefficient beta of an ideal gas mixture depends only on its temperature T, and its value is derived from the ideal gas law (i.e., beta = 1/RT, R being the ideal gas constant). But real gases behave as ideal gases only at low pressures, and this would not be the case in deep diving. High pressures of helium-oxygen are used in human and animal experimental dives (up to 7 or 12 MPa or more, respectively). At such pressures deviations from the ideal gas law cannot be neglected in hyperbaric atmospheres with respect to current accuracy of measuring instruments. As shown both theoretically and experimentally by this study, the non-ideal nature of helium-oxygen has a significant effect on the capacitance coefficient of hyperbaric atmospheres. The theoretical study is based on interaction energy in either homogeneous (He-He and O2-O2) or heterogeneous (He-O2) molecular pairs, and on the virial equation of state for gas mixtures. The experimental study is based on weight determination of samples of known volume of binary helium-oxygen mixtures, which are prepared in well-controlled pressure and temperature conditions. Our experimental results are in good agreement with theoretical predictions. 1) The helium compressibility factor ZHe increases linearly with pressure [ZHe = 1 + 0.0045 P (in MPa) at 30 degrees C]; and 2) in same temperature and pressure conditions (T = 303 K and P = 0.1 to 15 MPa), the same value for Z is valid for a helium-oxygen binary mixture and for pure helium. As derived from the equation of state of real gases, the capacitance coefficient is inversely related to Z (beta = 1/ZRT); therefore, for helium-oxygen mixtures, this coefficient would decrease with increasing pressure. A table is given for theoretical values of helium-oxygen capacitance coefficient, at pressures ranging from 0.1 to 15.0 MPa and at temperatures ranging from 25 degrees C to 37 degrees C.

Limits on relief through constrained exchange on random graphs

NASA Astrophysics Data System (ADS)

LaViolette, Randall A.; Ellebracht, Lory A.; Gieseler, Charles J.

2007-09-01

Agents are represented by nodes on a random graph (e.g., “small world”). Each agent is endowed with a zero-mean random value that may be either positive or negative. All agents attempt to find relief, i.e., to reduce the magnitude of that initial value, to zero if possible, through exchanges. The exchange occurs only between the agents that are linked, a constraint that turns out to dominate the results. The exchange process continues until Pareto equilibrium is achieved. Only 40-90% of the agents achieved relief on small-world graphs with mean degree between 2 and 40. Even fewer agents achieved relief on scale-free-like graphs with a truncated power-law degree distribution. The rate at which relief grew with increasing degree was slow, only at most logarithmic for all of the graphs considered; viewed in reverse, the fraction of nodes that achieve relief is resilient to the removal of links.

The control of tonic pain by active relief learning

PubMed Central

Mano, Hiroaki; Lee, Michael; Yoshida, Wako; Kawato, Mitsuo; Robbins, Trevor W

2018-01-01

Tonic pain after injury characterises a behavioural state that prioritises recovery. Although generally suppressing cognition and attention, tonic pain needs to allow effective relief learning to reduce the cause of the pain. Here, we describe a central learning circuit that supports learning of relief and concurrently suppresses the level of ongoing pain. We used computational modelling of behavioural, physiological and neuroimaging data in two experiments in which subjects learned to terminate tonic pain in static and dynamic escape-learning paradigms. In both studies, we show that active relief-seeking involves a reinforcement learning process manifest by error signals observed in the dorsal putamen. Critically, this system uses an uncertainty (‘associability’) signal detected in pregenual anterior cingulate cortex that both controls the relief learning rate, and endogenously and parametrically modulates the level of tonic pain. The results define a self-organising learning circuit that reduces ongoing pain when learning about potential relief. PMID:29482716

Ultra high vacuum pumping system and high sensitivity helium leak detector

DOEpatents

Myneni, Ganapati Rao

1997-01-01

An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10.sup.-13 atm cc s.sup.-1. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces backstreaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium.

Ultra high vacuum pumping system and high sensitivity helium leak detector

DOEpatents

Myneni, G.R.

1997-12-30

An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10{sup {minus}13} atm cc/s. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces back streaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium. 2 figs.

R-axion detection at LHC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goh, Hock-Seng; /UC, Berkeley /LBL, Berkeley; Ibe, Masahiro

2009-06-19

Supersymmetric models with spontaneously broken approximate R-symmetry contains a light spin 0 particle, the R-axion. The properties of the particle can be a powerful probe of the structure of the new physics. In this paper, we discuss the possibilities of the R-axion detection at the LHC experiments. It is challenge to observe this light particle in the LHC environment. However, for typical values in which the mass of the R-axion is a few hundred MeV, we show that those particles can be detected by searching for displaced vertices from R-axion decay.

2. SOUTHEAST SIDE. HIGH PRESSURE HELIUM STORAGE TANKS AT LEFT. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. SOUTHEAST SIDE. HIGH PRESSURE HELIUM STORAGE TANKS AT LEFT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Helium Compression Plant, Test Area 1-115, intersection of Altair & Saturn Boulevards, Boron, Kern County, CA

Helium refrigeration system for hydrogen liquefaction applications

NASA Astrophysics Data System (ADS)

Nair, J. Kumar, Sr.; Menon, RS; Goyal, M.; Ansari, NA; Chakravarty, A.; Joemon, V.

2017-02-01

Liquid hydrogen around 20 K is used as cold moderator for generating “cold neutron beam” in nuclear research reactors. A cryogenic helium refrigeration system is the core upon which such hydrogen liquefaction applications are built. A thermodynamic process based on reversed Brayton cycle with two stage expansion using high speed cryogenic turboexpanders (TEX) along with a pair of compact high effectiveness process heat exchangers (HX), is well suited for such applications. An existing helium refrigeration system, which had earlier demonstrated a refrigeration capacity of 470 W at around 20 K, is modified based on past operational experiences and newer application requirements. Modifications include addition of a new heat exchanger to simulate cryogenic process load and two other heat exchangers for controlling the temperatures of helium streams leading out to the application system. To incorporate these changes, cryogenic piping inside the cold box is suitably modified. This paper presents process simulation, sizing of new heat exchangers as well as fabrication aspects of the modified cryogenic process piping.

Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load

NASA Technical Reports Server (NTRS)

Garcia, Sam; Meagher, Daniel; Linza, Robert; Saheli, Fariborz; Vargas, Gerardo; Lauterbach, John; Reis, Carl; Ganni, Venkatarao (Rao); Homan, Jonathan

2008-01-01

NASA s Johnson Space Center (JSC) Building 32 houses two large thermal-vacuum chambers (Chamber A and Chamber B). Within these chambers are liquid nitrogen shrouds to provide a thermal environment and helium panels which operate at 20K to provide cryopumping. Some amount of air leakage into the chambers during tests is inevitable. This causes "air fouling" of the helium panel surfaces due to the components of the air that adhere to the panels. The air fouling causes the emittance of the helium panels to increase during tests. The increase in helium panel emittance increases the heat load on the helium refrigerator that supplies the 20K helium for those panels. Planning for thermal-vacuum tests should account for this increase to make sure that the helium refrigerator capacity will not be exceeded over the duration of a test. During a recent test conducted in Chamber B a known-size air leak was introduced to the chamber. Emittance change of the helium panels and the affect on the helium refrigerator was characterized. A description of the test and the results will be presented.

Refuge alternatives relief valve testing and design with updated test stand.

PubMed

Lutz, T J; Bissert, P T; Homce, G T; Yonkey, J A

2018-03-01

Underground refuge alternatives require an air source to supply breathable air to the occupants. This requires pressure relief valves to prevent unsafe pressures from building up within the refuge alternative. The U.S. Mine Safety and Health Administration (MSHA) mandates that pressure relief valves prevent pressure from exceeding 1.25 kPa (0.18 psi), or as specified by the manufacturer, above mine atmospheric pressure when a fan or compressor is used for the air supply. The U.S. National Institute for Occupational Safety and Health (NIOSH) tested a variety of pressure relief valves using an instrumented test fixture consisting of data acquisition equipment, a centrifugal blower, ductwork and various sensors to determine if the subject pressure relief valves meet the MSHA requirement. Relief pressures and flow characteristics, including opening pressure and flow rate, were measured for five different pressure relief valves under a variety of conditions. The subject pressure relief valves included two off-the-shelf modified check valves, two check valves used in MSHA-approved built-in-place refuge alternatives, and a commercially available valve that was designed for a steel refuge alternative and is currently being used in some built-in-place refuge alternatives. The test results showed relief pressures ranging from 0.20 to 1.53 kPa (0.03 to 0.22 psi) and flow rates up to 19.3 m 3 /min (683 scfm). As tested, some of the pressure relief valves did not meet the 1.25 kPa (0.18 psi) relief specification.

Refuge alternatives relief valve testing and design with updated test stand

PubMed Central

Lutz, T.J.; Bissert, P.T.; Homce, G.T.; Yonkey, J.A.

2018-01-01

Underground refuge alternatives require an air source to supply breathable air to the occupants. This requires pressure relief valves to prevent unsafe pressures from building up within the refuge alternative. The U.S. Mine Safety and Health Administration (MSHA) mandates that pressure relief valves prevent pressure from exceeding 1.25 kPa (0.18 psi), or as specified by the manufacturer, above mine atmospheric pressure when a fan or compressor is used for the air supply. The U.S. National Institute for Occupational Safety and Health (NIOSH) tested a variety of pressure relief valves using an instrumented test fixture consisting of data acquisition equipment, a centrifugal blower, ductwork and various sensors to determine if the subject pressure relief valves meet the MSHA requirement. Relief pressures and flow characteristics, including opening pressure and flow rate, were measured for five different pressure relief valves under a variety of conditions. The subject pressure relief valves included two off-the-shelf modified check valves, two check valves used in MSHA-approved built-in-place refuge alternatives, and a commercially available valve that was designed for a steel refuge alternative and is currently being used in some built-in-place refuge alternatives. The test results showed relief pressures ranging from 0.20 to 1.53 kPa (0.03 to 0.22 psi) and flow rates up to 19.3 m3/min (683 scfm). As tested, some of the pressure relief valves did not meet the 1.25 kPa (0.18 psi) relief specification. PMID:29563650

Compact Instruments Measure Helium-Leak Rates

NASA Technical Reports Server (NTRS)

Stout, Stephen; Immer, Christopher

2003-01-01

Compact, lightweight instruments have been developed for measuring small flows of helium and/or detecting helium leaks in solenoid valves when the valves are nominally closed. These instruments do not impede the flows when the valves are nominally open. They can be integrated into newly fabricated valves or retrofitted to previously fabricated valves. Each instrument includes an upstream and a downstream thermistor separated by a heater, plus associated analog and digital heater-control, signal- conditioning, and data-processing circuits. The thermistors and heater are off-the-shelf surface mount components mounted on a circuit board in the flow path. The operation of the instrument is based on a well-established thermal mass-flow-measurement technique: Convection by the flow that one seeks to measure gives rise to transfer of heat from the heater to the downstream thermistor. The temperature difference measured by the thermistors is directly related to the rate of flow. The calibration curve from temperature gradient to helium flow is closely approximated via fifth-order polynomial. A microprocessor that is part of the electronic circuitry implements the calibration curve to compute the flow rate from the thermistor readings.

49 CFR 179.500-16 - Tests of pressure relief devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Tests of pressure relief devices. 179.500-16... FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be...

Bas-relief generation using adaptive histogram equalization.

PubMed

Sun, Xianfang; Rosin, Paul L; Martin, Ralph R; Langbein, Frank C

2009-01-01

An algorithm is presented to automatically generate bas-reliefs based on adaptive histogram equalization (AHE), starting from an input height field. A mesh model may alternatively be provided, in which case a height field is first created via orthogonal or perspective projection. The height field is regularly gridded and treated as an image, enabling a modified AHE method to be used to generate a bas-relief with a user-chosen height range. We modify the original image-contrast-enhancement AHE method to use gradient weights also to enhance the shape features of the bas-relief. To effectively compress the height field, we limit the height-dependent scaling factors used to compute relative height variations in the output from height variations in the input; this prevents any height differences from having too great effect. Results of AHE over different neighborhood sizes are averaged to preserve information at different scales in the resulting bas-relief. Compared to previous approaches, the proposed algorithm is simple and yet largely preserves original shape features. Experiments show that our results are, in general, comparable to and in some cases better than the best previously published methods.

Periodic spectrum variations in helium-rich stars

NASA Technical Reports Server (NTRS)

Walborn, N. R.

1982-01-01

Spectroscopic observations of four helium-rich stars are presented. In HD 37776, antiphase variations of Si III and He I have been found, which represent another point of similarity to the Ap phenomenon. The remarkable H-alpha emission variations in Sigma Ori E are illustrated with uniform phase coverage, and strict periodicity over a five-year interval is shown. A radial-velocity study of HD 64740 shows constancy to within the accuracy of the observations. Finally, Delta Ori B is confirmed as a helium-rich star.

A forward model for the helium plume effect and the interpretation of helium charge exchange measurements at ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Kappatou, A.; McDermott, R. M.; Pütterich, T.; Dux, R.; Geiger, B.; Jaspers, R. J. E.; Donné, A. J. H.; Viezzer, E.; Cavedon, M.; the ASDEX Upgrade Team

2018-05-01

The analysis of the charge exchange measurements of helium is hindered by an additional emission contributing to the spectra, the helium ‘plume’ emission (Fonck et al 1984 Phys. Rev. A 29 3288), which complicates the interpretation of the measurements. The plume emission is indistinguishable from the active charge exchange signal when standard analysis of the spectra is applied and its intensity is of comparable magnitude for ASDEX Upgrade conditions, leading to a significant overestimation of the He2+ densities if not properly treated. Furthermore, the spectral line shape of the plume emission is non-Gaussian and leads to wrong ion temperature and flow measurements when not taken into account. A kinetic model for the helium plume emission has been developed for ASDEX Upgrade. The model is benchmarked against experimental measurements and is shown to capture the underlying physics mechanisms of the plume effect, as it can reproduce the experimental spectra and provides consistent values for the ion temperature, plasma rotation, and He2+ density.

Tables of thermodynamic properties of helium magnet coolant, revision A

NASA Astrophysics Data System (ADS)

McAshan, M.

1992-07-01

The most complete treatment of the thermodynamic properties of helium at the present time is the monograph by McCarty: 'Thermodynamic Properties of Helium 4 from 2 to 1500 K at Pressures to 10(exp 8) Pa', Robert D. McCarty, Journal of Physical and Chemical Reference Data, Vol. 2, page 923-1040 (1973). In this work the complete range of data on helium is examined and the P-V-T surface is described by an equation of state consisting of three functions P(r,T) covering different regions together with rules for making the transition from one region to another. From this thermodynamic compilation together with correlations of the transport properties of helium was published the well-known NBS Technical Note: 'Thermophysical Properties of Helium 4 from 2 to 1500 K with pressures to 1000 Atmospheres', Robert D. McCarty, US Department of Commerce, National Bureau of Standards Technical Note 631 (1972). This is the standard reference for helium cryogenics. The NBS 631 tables cover a wide range of temperature and pressure, and as a consequence, the number of points tabulated in the region of the single phase coolant for the SSC magnets are relatively few. The present work sets out to cover the range of interest in more detail in a way that is consistent with NBS 631. This new table is essentially identical to the older one and can be used as an auxiliary to it.

8. ORIGINAL HELIUM COMPRESSOR, CIRCA 1957, BY HASKELL ENGINEERING, GLENDALE, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. ORIGINAL HELIUM COMPRESSOR, CIRCA 1957, BY HASKELL ENGINEERING, GLENDALE, CALIFORNIA. Looking north. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Helium Compression Plant, Test Area 1-115, intersection of Altair & Saturn Boulevards, Boron, Kern County, CA

46 CFR 38.25-10 - Safety relief valves-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Safety relief valves-TB/ALL. 38.25-10 Section 38.25-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Periodic Tests and Inspections § 38.25-10 Safety relief valves—TB/ALL. (a) The cargo tank safety relief valves shall...

46 CFR 38.25-10 - Safety relief valves-TB/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false Safety relief valves-TB/ALL. 38.25-10 Section 38.25-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Periodic Tests and Inspections § 38.25-10 Safety relief valves—TB/ALL. (a) The cargo tank safety relief valves shall...

46 CFR 38.25-10 - Safety relief valves-TB/ALL.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false Safety relief valves-TB/ALL. 38.25-10 Section 38.25-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Periodic Tests and Inspections § 38.25-10 Safety relief valves—TB/ALL. (a) The cargo tank safety relief valves shall...

46 CFR 38.25-10 - Safety relief valves-TB/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false Safety relief valves-TB/ALL. 38.25-10 Section 38.25-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Periodic Tests and Inspections § 38.25-10 Safety relief valves—TB/ALL. (a) The cargo tank safety relief valves shall...

46 CFR 38.25-10 - Safety relief valves-TB/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 1 2014-10-01 2014-10-01 false Safety relief valves-TB/ALL. 38.25-10 Section 38.25-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Periodic Tests and Inspections § 38.25-10 Safety relief valves—TB/ALL. (a) The cargo tank safety relief valves shall...

49 CFR 179.500-16 - Tests of pressure relief devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Tests of pressure relief devices. 179.500-16... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air...

49 CFR 179.500-16 - Tests of pressure relief devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Tests of pressure relief devices. 179.500-16... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air...

49 CFR 179.500-16 - Tests of pressure relief devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Tests of pressure relief devices. 179.500-16... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air...

49 CFR 179.500-16 - Tests of pressure relief devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Tests of pressure relief devices. 179.500-16... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air...

Does pain relief by CT-guided indirect cervical nerve root injection with local anesthetics and steroids predict pain relief after decompression surgery for cervical nerve root compression?

PubMed

Antoniadis, Alexander; Dietrich, Tobias J; Farshad, Mazda

2016-10-01

The relationship of pain relief from a recently presented CT-guided indirect cervical nerve root injection with local anesthetics and steroids to surgical decompression as a treatment for single-level cervical radiculopathy is not clear. This retrospective study aimed to compare the immediate and 6-week post-injection effects to the short- and long-term outcomes after surgical decompression, specifically in regard to pain relief. Patients (n = 39, age 47 ± 10 years) who had undergone CT-guided indirect injection with local anesthetics and steroids as an initial treatment for single cervical nerve root radiculopathy and who subsequently needed surgical decompression were included retrospectively. Pain levels (VAS scores) were monitored before, immediately after, and 6 weeks after injection (n = 34), as well as 6 weeks (n = 38) and a mean of 25 months (SD ± 12) after surgical decompression (n = 36). Correlation analysis was performed to find potential associations of pain relief after injection and after surgery to investigate the predictive value of post-injection pain relief. There was no correlation between immediate pain relief after injection (-32 ± 27 %) and 6 weeks later (-7 ± 19 %), (r = -0.023, p = 0.900). There was an association by tendency between immediate pain relief after injection and post-surgical pain relief at 6 weeks (-82 ± 27 %), (r = 0.28, p = 0.08). Pain relief at follow-up remained high at -70 ± 21 % and was correlated with the immediate pain amelioration effect of the injection (r = 0.37, p = 0.032). Five out of seven patients who reported no pain relief from injection had a pain relief from surgery in excess of 50 %. The amount of immediate radiculopathic pain relief after indirect cervical nerve root injection is associated with the amount of pain relief achieved at long-term follow-up after surgical decompression of single-level cervical radiculopathy

Refuge alternatives relief valve testing and design

PubMed Central

Lutz, T.J.; Bissert, P.T.; Homce, G.T.; Yonkey, J.A.

2016-01-01

The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer’s steel prefabricated RAs and had been adapted for use in one mine operator’s built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer’s specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster. PMID:28018003

Rectangular Relief Diffraction Gratings for Coherent Lidar Beam Scanning

NASA Technical Reports Server (NTRS)

Cole, H. J.; Chambers, D. M.; Dixit, S. N.; Britten, J. A.; Shore, B. W.; Kavaya, M. J.

1999-01-01

The application of specialized rectangular relief transmission gratings to coherent lidar beam scanning is presented. Two types of surface relief transmission grating approaches are studied with an eye toward potential insertion of a constant thickness, diffractive scanner where refractive wedges now exist. The first diffractive approach uses vertically oriented relief structure in the surface of an optical flat; illumination of the diffractive scanner is off-normal in nature. The second grating design case describes rectangular relief structure slanted at a prescribed angle with respect to the surface. In this case, illumination is normal to the diffractive scanner. In both cases, performance predictions for 2.0 micron, circularly polarized light at beam deflection angles of 30 or 45 degrees are presented.

5. INTERIOR, LOOKING PAST HELIUM COMPRESSORS NO. 3 AND NO. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. INTERIOR, LOOKING PAST HELIUM COMPRESSORS NO. 3 AND NO. 2, TO NORTHEAST FRONT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Helium Compression Plant, Test Area 1-115, intersection of Altair & Saturn Boulevards, Boron, Kern County, CA

43 CFR 16.1 - Agreements to dispose of helium in natural gas.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Agreements to dispose of helium in natural gas. 16.1 Section 16.1 Public Lands: Interior Office of the Secretary of the Interior CONSERVATION OF HELIUM § 16.1 Agreements to dispose of helium in natural gas. (a) Pursuant to his authority and...

43 CFR 16.1 - Agreements to dispose of helium in natural gas.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Agreements to dispose of helium in natural gas. 16.1 Section 16.1 Public Lands: Interior Office of the Secretary of the Interior CONSERVATION OF HELIUM § 16.1 Agreements to dispose of helium in natural gas. (a) Pursuant to his authority and...

Equation of state of fluid helium at high temperatures and densities

NASA Astrophysics Data System (ADS)

Cai, Lingcang; Chen, Qifeng; Gu, Yunjun; Zhang, Ying; Zhou, Xianming; Jing, Fuqian

2005-03-01

Hugoniot curves and shock temperatures of gas helium with initial temperature 293 K and three initial pressures 0.6, 1.2, and 5.0 MPa were measured up to 15000 K using a two-stage light-gas gun and transient radiation pyrometer. It was found that the calculated Hugoniot EOS of gas helium at the same initial pressure using Saha equation with Debye-Hückel correction was in good agreement with the experimental data. The curve of the calculated shock wave velocity with the particle velocity of gas helium which is shocked from the initial pressure 5 MPa and temperature 293 K, i.e., the D ≈ u relation, D= C 0+λ u ( u<10 km/s, λ=1.32) in a low pressure region, is approximately parallel with the fitted D ≈ u (λ=1.36) of liquid helium from the experimental data of Nellis et al. Our calculations show that the Hugoniot parameter λ is independent of the initial density p{in0}. The D≈ u curves of gas helium will transfer to another one and approach a limiting value of compression when their temperature elevates to about 18000 K and the ionization degree of the shocked gas helium reaches 10-3.

46 CFR 38.10-15 - Safety relief valves-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Safety relief valves-TB/ALL. 38.10-15 Section 38.10-15..., Fittings, and Accessory Equipment § 38.10-15 Safety relief valves—TB/ALL. (a) Each tank shall be fitted with or (subject to approval by the Commandant) connected to one or more safety relief valves designed...

A Neurogenetic Dissociation between Punishment-, Reward-, and Relief-Learning in Drosophila

PubMed Central

Yarali, Ayse; Gerber, Bertram

2010-01-01

What is particularly worth remembering about a traumatic experience is what brought it about, and what made it cease. For example, fruit flies avoid an odor which during training had preceded electric shock punishment; on the other hand, if the odor had followed shock during training, it is later on approached as a signal for the relieving end of shock. We provide a neurogenetic analysis of such relief learning. Blocking, using UAS-shibirets1, the output from a particular set of dopaminergic neurons defined by the TH-Gal4 driver partially impaired punishment learning, but left relief learning intact. Thus, with respect to these particular neurons, relief learning differs from punishment learning. Targeting another set of dopaminergic/serotonergic neurons defined by the DDC-Gal4 driver on the other hand affected neither punishment nor relief learning. As for the octopaminergic system, the tbhM18 mutation, compromising octopamine biosynthesis, partially impaired sugar-reward learning, but not relief learning. Thus, with respect to this particular mutation, relief learning, and reward learning are dissociated. Finally, blocking output from the set of octopaminergic/tyraminergic neurons defined by the TDC2-Gal4 driver affected neither reward, nor relief learning. We conclude that regarding the used genetic tools, relief learning is neurogenetically dissociated from both punishment and reward learning. This may be a message relevant also for analyses of relief learning in other experimental systems including man. PMID:21206762

Processing LHC data in the UK

PubMed Central

Colling, D.; Britton, D.; Gordon, J.; Lloyd, S.; Doyle, A.; Gronbech, P.; Coles, J.; Sansum, A.; Patrick, G.; Jones, R.; Middleton, R.; Kelsey, D.; Cass, A.; Geddes, N.; Clark, P.; Barnby, L.

2013-01-01

The Large Hadron Collider (LHC) is one of the greatest scientific endeavours to date. The construction of the collider itself and the experiments that collect data from it represent a huge investment, both financially and in terms of human effort, in our hope to understand the way the Universe works at a deeper level. Yet the volumes of data produced are so large that they cannot be analysed at any single computing centre. Instead, the experiments have all adopted distributed computing models based on the LHC Computing Grid. Without the correct functioning of this grid infrastructure the experiments would not be able to understand the data that they have collected. Within the UK, the Grid infrastructure needed by the experiments is provided by the GridPP project. We report on the operations, performance and contributions made to the experiments by the GridPP project during the years of 2010 and 2011—the first two significant years of the running of the LHC. PMID:23230163

How absent negativity relates to affect and motivation: an integrative relief model

PubMed Central

Deutsch, Roland; Smith, Kevin J. M.; Kordts-Freudinger, Robert; Reichardt, Regina

2015-01-01

The present paper concerns the motivational underpinnings and behavioral correlates of the prevention or stopping of negative stimulation – a situation referred to as relief. Relief is of great theoretical and applied interest. Theoretically, it is tied to theories linking affect, emotion, and motivational systems. Importantly, these theories make different predictions regarding the association between relief and motivational systems. Moreover, relief is a prototypical antecedent of counterfactual emotions, which involve specific cognitive processes compared to factual or mere anticipatory emotions. Practically, relief may be an important motivator of addictive and phobic behaviors, self destructive behaviors, and social influence. In the present paper, we will first provide a review of conflicting conceptualizations of relief. We will then present an integrative relief model (IRMO) that aims at resolving existing theoretical conflicts. We then review evidence relevant to distinctive predictions regarding the moderating role of various procedural features of relief situations. We conclude that our integrated model results in a better understanding of existing evidence on the affective and motivational underpinnings of relief, but that further evidence is needed to come to a more comprehensive evaluation of the viability of IRMO. PMID:25806008

How absent negativity relates to affect and motivation: an integrative relief model.

PubMed

Deutsch, Roland; Smith, Kevin J M; Kordts-Freudinger, Robert; Reichardt, Regina

2015-01-01

The present paper concerns the motivational underpinnings and behavioral correlates of the prevention or stopping of negative stimulation - a situation referred to as relief. Relief is of great theoretical and applied interest. Theoretically, it is tied to theories linking affect, emotion, and motivational systems. Importantly, these theories make different predictions regarding the association between relief and motivational systems. Moreover, relief is a prototypical antecedent of counterfactual emotions, which involve specific cognitive processes compared to factual or mere anticipatory emotions. Practically, relief may be an important motivator of addictive and phobic behaviors, self destructive behaviors, and social influence. In the present paper, we will first provide a review of conflicting conceptualizations of relief. We will then present an integrative relief model (IRMO) that aims at resolving existing theoretical conflicts. We then review evidence relevant to distinctive predictions regarding the moderating role of various procedural features of relief situations. We conclude that our integrated model results in a better understanding of existing evidence on the affective and motivational underpinnings of relief, but that further evidence is needed to come to a more comprehensive evaluation of the viability of IRMO.

Diffuse Helium Emission as a Precursory Sign of Volcanic Unrest

NASA Astrophysics Data System (ADS)

Padron, E.; Perez, N.; Hernandez Perez, P. A.; Sumino, H.; Melian Rodriguez, G.; Barrancos, J.; Nolasco, D.; Padilla, G.; Dionis, S.; Rodriguez, F.; Hernandez, I.; Calvo, D.; Peraza, M.; Nagao, K.

2012-12-01

Since July 16, 2011, an anomalous seismicity at El Hierro island, the youngest and smallest of the Canary Islands, was recorded by IGN seismic network. After the occurrence of more than 10,000 seismic events, volcanic tremor was recorded since 05:15 of the October 10, by all of the seismic stations on the island, with highest amplitudes recorded in the southernmost station. During the afternoon of October 12 a large light-green coloured area was observed in the sea to the souht of La Restinga village (at the southernmost part of El Hierro island), suggesting the existence of a submarine eruption. Since October 12, frequent episodes of, turbulent gas emission and foaming, and the appearance of steamy lava fragments has been observed on the sea surface. As part of the volcanic surveillance of the island, the Instituto Volcanologico de Canarias (INVOLCAN) geochemical monitoring program is carrying out diffuse helium surveys on the surface environment of El Hierro (soil atmosphere). This nobel gas has been investigated because it has been considered an almost ideal geochemical indicator because it is chemically inert, physically stable, nonbiogenic, sparingly soluble in water under ambient conditions and almost non-adsorbable. At each survey, 600 sampling sites covering the whole island and following an homogeneous distribution are selected for helium measurements in the soil gases, The helium concentration gradients with respect to its value on air (5.24 ppm) allow us to estimate a pure diffusive emission rate of helium throughout the island. The first survey was carried out on the summer of 2003, when the island was on a quiescence period. At this survey, the amount of helium released by the volcanic system of El Hierro was estimated in 6 kg/d. Since the beginning of the seismic unrest, 13 helium emission surveys have been carried out. The helium emission rate has shown an excellent agreement with the evolution of the volcanic crisis of the island, reaching 30 kg

7 CFR 3201.59 - Topical pain relief products.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false Topical pain relief products. 3201.59 Section 3201.59... MANAGEMENT, DEPARTMENT OF AGRICULTURE GUIDELINES FOR DESIGNATING BIOBASED PRODUCTS FOR FEDERAL PROCUREMENT Designated Items § 3201.59 Topical pain relief products. (a) Definition. Products that can be balms, creams...

7 CFR 3201.59 - Topical pain relief products.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 15 2012-01-01 2012-01-01 false Topical pain relief products. 3201.59 Section 3201.59... MANAGEMENT, DEPARTMENT OF AGRICULTURE GUIDELINES FOR DESIGNATING BIOBASED PRODUCTS FOR FEDERAL PROCUREMENT Designated Items § 3201.59 Topical pain relief products. (a) Definition. Products that can be balms, creams...

7 CFR 3201.59 - Topical pain relief products.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 15 2013-01-01 2013-01-01 false Topical pain relief products. 3201.59 Section 3201.59... MANAGEMENT, DEPARTMENT OF AGRICULTURE GUIDELINES FOR DESIGNATING BIOBASED PRODUCTS FOR FEDERAL PROCUREMENT Designated Items § 3201.59 Topical pain relief products. (a) Definition. Products that can be balms, creams...

46 CFR 154.912 - Inerted spaces: Relief devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces must...

46 CFR 154.912 - Inerted spaces: Relief devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces must...

46 CFR 154.912 - Inerted spaces: Relief devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces must...

46 CFR 154.912 - Inerted spaces: Relief devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces must...

46 CFR 154.912 - Inerted spaces: Relief devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces must...

The influence of dislocation and hydrogen on thermal helium desorption behavior in Fe9Cr alloys

NASA Astrophysics Data System (ADS)

Zhu, Te; Jin, Shuoxue; Gong, Yihao; Lu, Eryang; Song, Ligang; Xu, Qiu; Guo, Liping; Cao, Xingzhong; Wang, Baoyi

2017-11-01

Transmutation helium may causes serious embrittlement which is considered to be due to helium from clustering as a bubble in materials. Suppression of transmutation helium can be achieved by introducing trapping sites such as dislocations and impurities in materials. Here, effects of intentionally-induced dislocations and hydrogen on helium migrate and release behaviors were investigated using thermal desorption spectrometry (TDS) technique applied to well-annealed and cold-worked Fe9Cr alloys irradiated by energetic helium/hydrogen ions. Synchronous desorption of helium and hydrogen was observed, and the microstructure states during helium release at different temperatures were analyzed. High thermally stable HenD type complexes formed in cold-worked specimens, resulting in the retardation of helium migration and release. The existence of hydrogen will strongly affect the thermal helium desorption which could be reflected in the TDS spectrum. It was confirmed that hydrogen retained in the specimens can result in obvious delay of helium desorption.

Thermophysicochemical Reaction of ZrCo-Hydrogen-Helium System

NASA Astrophysics Data System (ADS)

Jung, Kwangjin; Kang, Hee-Seok; Yun, Sei-Hun; Chung, Hongsuk

2017-11-01

Nuclear fusion energy, which is clean and infinite, has been studied for more than half a century. Efforts are in progress worldwide for the demonstration and validation of nuclear fusion energy. Korea has been developing hydrogen isotope storage and delivery system (SDS) technologies including a basic scientific study on a hydrogen storage medium. An SDS bed, which is a key component of the SDS, is used for storing hydrogen isotopes in a metal hydride form and supplying them to a tokamak. Thermophysicochemical properties of the ZrCo-H2-He system are investigated for the practical utilization of a hydriding alloy system. The hydriding reaction, in which ZrCoHx is composed as ZrCo absorbing hydrogen, is exothermic. The dehydriding reaction, in which ZrCoHx decomposes into ZrCo and hydrogen, is endothermic. The heat generated through the hydriding reaction interrupts the hydriding progress. The heat loss by a dehydriding reaction impedes the dehydriding progress. The tritium decay product, helium-3, covers the ZrCo and keeps the hydrogen from contact with ZrCo in the SDS bed. In this study, we designed and fabricated a ZrCo bed and its performance test rig. The helium blanketing effect on a ZrCo hydrogen reaction with 0 % to 20 % helium content in a gaseous phase and a helium blanket removal method were studied experimentally. In addition, the volumetric flow rates and temperature at the beginning of a ZrCo hydrogen reaction in a hydrogen or helium atmosphere, and the cooling of the SDS bed by radiation only and by both radiation and natural convection related to the reuse cycle, were obtained.

The ALICE experiment at the CERN LHC

NASA Astrophysics Data System (ADS)

ALICE Collaboration; Aamodt, K.; Abrahantes Quintana, A.; Achenbach, R.; Acounis, S.; Adamová, D.; Adler, C.; Aggarwal, M.; Agnese, F.; Aglieri Rinella, G.; Ahammed, Z.; Ahmad, A.; Ahmad, N.; Ahmad, S.; Akindinov, A.; Akishin, P.; Aleksandrov, D.; Alessandro, B.; Alfaro, R.; Alfarone, G.; Alici, A.; Alme, J.; Alt, T.; Altinpinar, S.; Amend, W.; Andrei, C.; Andres, Y.; Andronic, A.; Anelli, G.; Anfreville, M.; Angelov, V.; Anzo, A.; Anson, C.; Anticić, T.; Antonenko, V.; Antonczyk, D.; Antinori, F.; Antinori, S.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Aprodu, V.; Arba, M.; Arcelli, S.; Argentieri, A.; Armesto, N.; Arnaldi, R.; Arefiev, A.; Arsene, I.; Asryan, A.; Augustinus, A.; Awes, T. C.; Äysto, J.; Danish Azmi, M.; Bablock, S.; Badalà, A.; Badyal, S. K.; Baechler, J.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baldit, A.; Bán, J.; Barbera, R.; Barberis, P.-L.; Barbet, J. M.; Barnäfoldi, G.; Barret, V.; Bartke, J.; Bartos, D.; Basile, M.; Basmanov, V.; Bastid, N.; Batigne, G.; Batyunya, B.; Baudot, J.; Baumann, C.; Bearden, I.; Becker, B.; Belikov, J.; Bellwied, R.; Belmont-Moreno, E.; Belogianni, A.; Belyaev, S.; Benato, A.; Beney, J. L.; Benhabib, L.; Benotto, F.; Beolé, S.; Berceanu, I.; Bercuci, A.; Berdermann, E.; Berdnikov, Y.; Bernard, C.; Berny, R.; Berst, J. D.; Bertelsen, H.; Betev, L.; Bhasin, A.; Baskar, P.; Bhati, A.; Bianchi, N.; Bielčik, J.; Bielčiková, J.; Bimbot, L.; Blanchard, G.; Blanco, F.; Blanco, F.; Blau, D.; Blume, C.; Blyth, S.; Boccioli, M.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Boldizsár, L.; Bombara, M.; Bombonati, C.; Bondila, M.; Bonnet, D.; Bonvicini, V.; Borel, H.; Borotto, F.; Borshchov, V.; Bortoli, Y.; Borysov, O.; Bose, S.; Bosisio, L.; Botje, M.; Böttger, S.; Bourdaud, G.; Bourrion, O.; Bouvier, S.; Braem, A.; Braun, M.; Braun-Munzinger, P.; Bravina, L.; Bregant, M.; Bruckner, G.; Brun, R.; Bruna, E.; Brunasso, O.; Bruno, G. E.; Bucher, D.; Budilov, V.; Budnikov, D.; Buesching, H.; Buncic, P.; Burns, M.; Burachas, S.; Busch, O.; Bushop, J.; Cai, X.; Caines, H.; Calaon, F.; Caldogno, M.; Cali, I.; Camerini, P.; Campagnolo, R.; Campbell, M.; Cao, X.; Capitani, G. P.; Romeo, G. Cara; Cardenas-Montes, M.; Carduner, H.; Carena, F.; Carena, W.; Cariola, P.; Carminati, F.; Casado, J.; Casanova Diaz, A.; Caselle, M.; Castillo Castellanos, J.; Castor, J.; Catanescu, V.; Cattaruzza, E.; Cavazza, D.; Cerello, P.; Ceresa, S.; Černý, V.; Chambert, V.; Chapeland, S.; Charpy, A.; Charrier, D.; Chartoire, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chepurnov, V.; Chernenko, S.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chochula, P.; Chiavassa, E.; Chibante Barroso, V.; Choi, J.; Christakoglou, P.; Christiansen, P.; Christensen, C.; Chykalov, O. A.; Cicalo, C.; Cifarelli-Strolin, L.; Ciobanu, M.; Cindolo, F.; Cirstoiu, C.; Clausse, O.; Cleymans, J.; Cobanoglu, O.; Coffin, J.-P.; Coli, S.; Colla, A.; Colledani, C.; Combaret, C.; Combet, M.; Comets, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Contin, G.; Contreras, J.; Cormier, T.; Corsi, F.; Cortese, P.; Costa, F.; Crescio, E.; Crochet, P.; Cuautle, E.; Cussonneau, J.; Dahlinger, M.; Dainese, A.; Dalsgaard, H. H.; Daniel, L.; Das, I.; Das, T.; Dash, A.; Da Silva, R.; Davenport, M.; Daues, H.; DeCaro, A.; de Cataldo, G.; DeCuveland, J.; DeFalco, A.; de Gaspari, M.; de Girolamo, P.; de Groot, J.; DeGruttola, D.; DeHaas, A.; DeMarco, N.; DePasquale, S.; DeRemigis, P.; de Vaux, D.; Decock, G.; Delagrange, H.; DelFranco, M.; Dellacasa, G.; Dell'Olio, C.; Dell'Olio, D.; Deloff, A.; Demanov, V.; Dénes, E.; D'Erasmo, G.; Derkach, D.; Devaux, A.; Di Bari, D.; Di Bartelomen, A.; Di Giglio, C.; Di Liberto, S.; Di Mauro, A.; Di Nezza, P.; Dialinas, M.; Diaz, L.; Díaz Valdes, R.; Dietel, T.; Dima, R.; Ding, H.; Dinca, C.; Divià, R.; Dobretsov, V.; Dobrin, A.; Doenigus, B.; Dobrowolski, T.; Domínguez, I.; Dorn, M.; Drouet, S.; Dubey, A. E.; Ducroux, L.; Dumitrache, F.; Dumonteil, E.; Dupieux, P.; Duta, V.; Dutta Majumdar, A.; Dutta Majumdar, M.; Dyhre, Th; Efimov, L.; Efremov, A.; Elia, D.; Emschermann, D.; Engster, C.; Enokizono, A.; Espagnon, B.; Estienne, M.; Evangelista, A.; Evans, D.; Evrard, S.; Fabjan, C. W.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Farano, R.; Fearick, R.; Fedorov, O.; Fekete, V.; Felea, D.; Feofilov, G.; Férnandez Téllez, A.; Ferretti, A.; Fichera, F.; Filchagin, S.; Filoni, E.; Finck, C.; Fini, R.; Fiore, E. M.; Flierl, D.; Floris, M.; Fodor, Z.; Foka, Y.; Fokin, S.; Force, P.; Formenti, F.; Fragiacomo, E.; Fragkiadakis, M.; Fraissard, D.; Franco, A.; Franco, M.; Frankenfeld, U.; Fratino, U.; Fresneau, S.; Frolov, A.; Fuchs, U.; Fujita, J.; Furget, C.; Furini, M.; Fusco Girard, M.; Gaardhøje, J.-J.; Gabrielli, A.; Gadrat, S.; Gagliardi, M.; Gago, A.; Gaido, L.; Gallas Torreira, A.; Gallio, M.; Gandolfi, E.; Ganoti, P.; Ganti, M.; Garabatos, J.; Garcia Lopez, A.; Garizzo, L.; Gaudichet, L.; Gemme, R.; Germain, M.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Giolu, G.; Giraudo, G.; Giubellino, P.; Glasow, R.; Glässel, P.; Ferreiro, E. G.; Gonzalez Gutierrez, C.; Gonzales-Trueba, L. H.; Gorbunov, S.; Gorbunov, Y.; Gos, H.; Gosset, J.; Gotovac, S.; Gottschlag, H.; Gottschalk, D.; Grabski, V.; Grassi, T.; Gray, H.; Grebenyuk, O.; Grebieszkow, K.; Gregory, C.; Grigoras, C.; Grion, N.; Grigoriev, V.; Grigoryan, A.; Grigoryan, C.; Grigoryan, S.; Grishuk, Y.; Gros, P.; Grosse-Oetringhaus, J.; Grossiord, J.-Y.; Grosso, R.; Grynyov, B.; Guarnaccia, C.; Guber, F.; Guerin, F.; Guernane, R.; Guerzoni, M.; Guichard, A.; Guida, M.; Guilloux, G.; Gulkanyan, H.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, V.; Gustafsson, H.-A.; Gutbrod, H.; Hadjidakis, C.; Haiduc, M.; Hamar, G.; Hamagaki, H.; Hamblen, J.; Hansen, J. C.; Hardy, P.; Hatzifotiadou, D.; Harris, J. W.; Hartig, M.; Harutyunyan, A.; Hayrapetyan, A.; Hasch, D.; Hasegan, D.; Hehner, J.; Heine, N.; Heinz, M.; Helstrup, H.; Herghelegiu, A.; Herlant, S.; Herrera Corral, G.; Herrmann, N.; Hetland, K.; Hille, P.; Hinke, H.; Hippolyte, B.; Hoch, M.; Hoebbel, H.; Hoedlmoser, H.; Horaguchi, T.; Horner, M.; Hristov, P.; Hřivnáčová, I.; Hu, S.; Guo, C. Hu; Humanic, T.; Hurtado, A.; Hwang, D. S.; Ianigro, J. C.; Idzik, M.; Igolkin, S.; Ilkaev, R.; Ilkiv, I.; Imhoff, M.; Innocenti, P. G.; Ionescu, E.; Ippolitov, M.; Irfan, M.; Insa, C.; Inuzuka, M.; Ivan, C.; Ivanov, A.; Ivanov, M.; Ivanov, V.; Jacobs, P.; Jacholkowski, A.; Jančurová, L.; Janik, R.; Jasper, M.; Jena, C.; Jirden, L.; Johnson, D. P.; Jones, G. T.; Jorgensen, C.; Jouve, F.; Jovanović, P.; Junique, A.; Jusko, A.; Jung, H.; Jung, W.; Kadija, K.; Kamal, A.; Kamermans, R.; Kapusta, S.; Kaidalov, A.; Kakoyan, V.; Kalcher, S.; Kang, E.; Kapitan, J.; Kaplin, V.; Karadzhev, K.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Karpio, K.; Kazantsev, A.; Kebschull, U.; Keidel, R.; Mohsin Khan, M.; Khanzadeev, A.; Kharlov, Y.; Kikola, D.; Kileng, B.; Kim, D.; Kim, D. S.; Kim, D. W.; Kim, H. N.; Kim, J. S.; Kim, S.; Kinson, J. B.; Kiprich, S. K.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, T.; Kiworra, V.; Klay, J.; Klein Bösing, C.; Kliemant, M.; Klimov, A.; Klovning, A.; Kluge, A.; Kluit, R.; Kniege, S.; Kolevatov, R.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kornas, E.; Koshurnikov, E.; Kotov, I.; Kour, R.; Kowalski, M.; Kox, S.; Kozlov, K.; Králik, I.; Kramer, F.; Kraus, I.; Kravčáková, A.; Krawutschke, T.; Krivda, M.; Kryshen, E.; Kucheriaev, Y.; Kugler, A.; Kuhn, C.; Kuijer, P.; Kumar, L.; Kumar, N.; Kumpumaeki, P.; Kurepin, A.; Kurepin, A. N.; Kushpil, S.; Kushpil, V.; Kutovsky, M.; Kvaerno, H.; Kweon, M.; Labbé, J.-C.; Lackner, F.; Ladron de Guevara, P.; Lafage, V.; La Rocca, P.; Lamont, M.; Lara, C.; Larsen, D. T.; Laurenti, G.; Lazzeroni, C.; LeBornec, Y.; LeBris, N.; LeGailliard, C.; Lebedev, V.; Lecoq, J.; Lee, K. S.; Lee, S. C.; Lefévre, F.; Legrand, I.; Lehmann, T.; Leistam, L.; Lenoir, P.; Lenti, V.; Leon, H.; Monzon, I. Leon; Lévai, P.; Li, Q.; Li, X.; Librizzi, F.; Lietava, R.; Lindegaard, N.; Lindenstruth, V.; Lippmann, C.; Lisa, M.; Listratenko, O. M.; Littel, F.; Liu, Y.; Lo, J.; Lobanov, V.; Loginov, V.; López Noriega, M.; López-Ramírez, R.; López Torres, E.; Lorenzo, P. M.; Løvhøiden, G.; Lu, S.; Ludolphs, W.; Lunardon, M.; Luquin, L.; Lusso, S.; Lutz, J.-R.; Luvisetto, M.; Lyapin, V.; Maevskaya, A.; Magureanu, C.; Mahajan, A.; Majahan, S.; Mahmoud, T.; Mairani, A.; Mahapatra, D.; Makarov, A.; Makhlyueva, I.; Malek, M.; Malkiewicz, T.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manea, C.; Mangotra, L. K.; Maniero, D.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Marcel, A.; Marchini, S.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marin, A.; Marin, J.-C.; Marras, D.; Martinengo, P.; Martínez, M. I.; Martinez-Davalos, A.; Martínez Garcia, G.; Martini, S.; Marzari Chiesa, A.; Marzocca, C.; Masciocchi, S.; Masera, M.; Masetti, M.; Maslov, N. I.; Masoni, A.; Massera, F.; Mast, M.; Mastroserio, A.; Matthews, Z. L.; Mayer, B.; Mazza, G.; Mazzaro, M. D.; Mazzoni, A.; Meddi, F.; Meleshko, E.; Menchaca-Rocha, A.; Meneghini, S.; Meoni, M.; Mercado Perez, J.; Mereu, P.; Meunier, O.; Miake, Y.; Michalon, A.; Michinelli, R.; Miftakhov, N.; Mignone, M.; Mikhailov, K.; Milosevic, J.; Minaev, Y.; Minafra, F.; Mischke, A.; Miśkowiec, D.; Mitsyn, V.; Mitu, C.; Mohanty, B.; Moisa, D.; Molnar, L.; Mondal, M.; Mondal, N.; Montaño Zetina, L.; Monteno, M.; Morando, M.; Morel, M.; Moretto, S.; Morhardt, Th; Morsch, A.; Moukhanova, T.; Mucchi, M.; Muccifora, V.; Mudnic, E.; Müller, H.; Müller, W.; Munoz, J.; Mura, D.; Musa, L.; Muraz, J. F.; Musso, A.; Nania, R.; Nandi, B.; Nappi, E.; Navach, F.; Navin, S.; Nayak, T.; Nazarenko, S.; Nazarov, G.; Nellen, L.; Nendaz, F.; Nianine, A.; Nicassio, M.; Nielsen, B. S.; Nikolaev, S.; Nikolic, V.; Nikulin, S.; Nikulin, V.; Nilsen, B.; Nitti, M.; Noferini, F.; Nomokonov, P.; Nooren, G.; Noto, F.; Nouais, D.; Nyiri, A.; Nystrand, J.; Odyniec, G.; Oeschler, H.; Oinonen, M.; Oldenburg, M.; Oleks, I.; Olsen, E. K.; Onuchin, V.; Oppedisano, C.; Orsini, F.; Ortiz-Velázquez, A.; Oskamp, C.; Oskarsson, A.; Osmic, F.; Österman, L.; Otterlund, I.; Ovrebekk, G.; Oyama, K.; Pachr, M.; Pagano, P.; Paić, G.; Pajares, C.; Pal, S.; Pal, S.; Pálla, G.; Palmeri, A.; Pancaldi, G.; Panse, R.; Pantaleo, A.; Pappalardo, G. S.; Pastirčák, B.; Pastore, C.; Patarakin, O.; Paticchio, V.; Patimo, G.; Pavlinov, A.; Pawlak, T.; Peitzmann, T.; Pénichot, Y.; Pepato, A.; Pereira, H.; Peresunko, D.; Perez, C.; Perez Griffo, J.; Perini, D.; Perrino, D.; Peryt, W.; Pesci, A.; Peskov, V.; Pestov, Y.; Peters, A. J.; Petráček, V.; Petridis, A.; Petris, M.; Petrov, V.; Petrov, V.; Petrovici, M.; Peyré, J.; Piano, S.; Piccotti, A.; Pichot, P.; Piemonte, C.; Pikna, M.; Pilastrini, R.; Pillot, P.; Pinazza, O.; Pini, B.; Pinsky, L.; Pinto Morais, V.; Pismennaya, V.; Piuz, F.; Platt, R.; Ploskon, M.; Plumeri, S.; Pluta, J.; Pocheptsov, T.; Podesta, P.; Poggio, F.; Poghosyan, M.; Poghosyan, T.; Polák, K.; Polichtchouk, B.; Polozov, P.; Polyakov, V.; Pommeresch, B.; Pompei, F.; Pop, A.; Popescu, S.; Posa, F.; Pospíšil, V.; Potukuchi, B.; Pouthas, J.; Prasad, S.; Preghenella, R.; Prino, F.; Prodan, L.; Prono, G.; Protsenko, M. A.; Pruneau, C. A.; Przybyla, A.; Pshenichnov, I.; Puddu, G.; Pujahari, P.; Pulvirenti, A.; Punin, A.; Punin, V.; Putschke, J.; Quartieri, J.; Quercigh, E.; Rachevskaya, I.; Rachevski, A.; Rademakers, A.; Radomski, S.; Radu, A.; Rak, J.; Ramello, L.; Raniwala, R.; Raniwala, S.; Rasmussen, O. B.; Rasson, J.; Razin, V.; Read, K.; Real, J.; Redlich, K.; Reichling, C.; Renard, C.; Renault, G.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Revol, J.-P.; Reygers, K.; Ricaud, H.; Riccati, L.; Ricci, R. A.; Richter, M.; Riedler, P.; Rigalleau, L. M.; Riggi, F.; Riegler, W.; Rindel, E.; Riso, J.; Rivetti, A.; Rizzi, M.; Rizzi, V.; Rodriguez Cahuantzi, M.; Røed, K.; Röhrich, D.; Román-López, S.; Romanato, M.; Romita, R.; Ronchetti, F.; Rosinsky, P.; Rosnet, P.; Rossegger, S.; Rossi, A.; Rostchin, V.; Rotondo, F.; Roukoutakis, F.; Rousseau, S.; Roy, C.; Roy, D.; Roy, P.; Royer, L.; Rubin, G.; Rubio, A.; Rui, R.; Rusanov, I.; Russo, G.; Ruuskanen, V.; Ryabinkin, E.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahoo, R.; Saini, J.; Saiz, P.; Salur, S.; Sambyal, S.; Samsonov, V.; Šándor, L.; Sandoval, A.; Sann, H.; Santiard, J.-C.; Santo, R.; Santoro, R.; Sargsyan, G.; Saturnini, P.; Scapparone, E.; Scarlassara, F.; Schackert, B.; Schiaua, C.; Schicker, R.; Schioler, T.; Schippers, J. D.; Schmidt, C.; Schmidt, H.; Schneider, R.; Schossmaier, K.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Schyns, E.; Scioli, G.; Scomparin, E.; Snow, H.; Sedykh, S.; Segato, G.; Sellitto, S.; Semeria, F.; Senyukov, S.; Seppänen, H.; Serci, S.; Serkin, L.; Serra, S.; Sesselmann, T.; Sevcenco, A.; Sgura, I.; Shabratova, G.; Shahoyan, R.; Sharkov, E.; Sharma, S.; Shigaki, K.; Shileev, K.; Shukla, P.; Shurygin, A.; Shurygina, M.; Sibiriak, Y.; Siddi, E.; Siemiarczuk, T.; Sigward, M. H.; Silenzi, A.; Silvermyr, D.; Silvestri, R.; Simili, E.; Simion, V.; Simon, R.; Simonetti, L.; Singaraju, R.; Singhal, V.; Sinha, B.; Sinha, T.; Siska, M.; Sitár, B.; Sitta, M.; Skaali, B.; Skowronski, P.; Slodkowski, M.; Smirnov, N.; Smykov, L.; Snellings, R.; Snoeys, W.; Soegaard, C.; Soerensen, J.; Sokolov, O.; Soldatov, A.; Soloviev, A.; Soltveit, H.; Soltz, R.; Sommer, W.; Soos, C.; Soramel, F.; Sorensen, S.; Soyk, D.; Spyropoulou-Stassinaki, M.; Stachel, J.; Staley, F.; Stan, I.; Stavinskiy, A.; Steckert, J.; Stefanini, G.; Stefanek, G.; Steinbeck, T.; Stelzer, H.; Stenlund, E.; Stocco, D.; Stockmeier, M.; Stoicea, G.; Stolpovsky, P.; Strmeň, P.; Stutzmann, J. S.; Su, G.; Sugitate, T.; Šumbera, M.; Suire, C.; Susa, T.; Sushil Kumar, K.; Swoboda, D.; Symons, J.; Szarka, I.; Szostak, A.; Szuba, M.; Szymanski, P.; Tadel, M.; Tagridis, C.; Tan, L.; Tapia Takaki, D.; Taureg, H.; Tauro, A.; Tavlet, M.; Tejeda Munoz, G.; Thäder, J.; Tieulent, R.; Timmer, P.; Tolyhy, T.; Topilskaya, N.; Torcato de Matos, C.; Torii, H.; Toscano, L.; Tosello, F.; Tournaire, A.; Traczyk, T.; Tröger, G.; Tromeur, W.; Truesdale, D.; Trzaska, W.; Tsiledakis, G.; Tsilis, E.; Tsvetkov, A.; Turcato, M.; Turrisi, R.; Tuveri, M.; Tveter, T.; Tydesjo, H.; Tykarski, L.; Tywoniuk, K.; Ugolini, E.; Ullaland, K.; Urbán, J.; Urciuoli, G. M.; Usai, G. L.; Usseglio, M.; Vacchi, A.; Vala, M.; Valiev, F.; Vande Vyvre, P.; Van Den Brink, A.; Van Eijndhoven, N.; Van Der Kolk, N.; van Leeuwen, M.; Vannucci, L.; Vanzetto, S.; Vanuxem, J.-P.; Vargas, M. A.; Varma, R.; Vascotto, A.; Vasiliev, A.; Vassiliou, M.; Vasta, P.; Vechernin, V.; Venaruzzo, M.; Vercellin, E.; Vergara, S.; Verhoeven, W.; Veronese, F.; Vetlitskiy, I.; Vernet, R.; Victorov, V.; Vidak, L.; Viesti, G.; Vikhlyantsev, O.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y.; Vodopianov, A.; Volpe, G.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Wabnitz, C.; Wagner, V.; Wallet, L.; Wan, R.; Wang, Y.; Wang, Y.; Wheadon, R.; Weis, R.; Wen, Q.; Wessels, J.; Westergaard, J.; Wiechula, J.; Wiesenaecker, A.; Wikne, J.; Wilk, A.; Wilk, G.; Williams, C.; Willis, N.; Windelband, B.; Witt, R.; Woehri, H.; Wyllie, K.; Xu, C.; Yang, C.; Yang, H.; Yermia, F.; Yin, Z.; Yin, Z.; Ky, B. Yun; Yushmanov, I.; Yuting, B.; Zabrodin, E.; Zagato, S.; Zagreev, B.; Zaharia, P.; Zalite, A.; Zampa, G.; Zampolli, C.; Zanevskiy, Y.; Zarochentsev, A.; Zaudtke, O.; Závada, P.; Zbroszczyk, H.; Zepeda, A.; Zeter, V.; Zgura, I.; Zhalov, M.; Zhou, D.; Zhou, S.; Zhu, G.; Zichichi, A.; Zinchenko, A.; Zinovjev, G.; Zoccarato, Y.; Zubarev, A.; Zucchini, A.; Zuffa, M.

2008-08-01

ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 16 × 16 × 26 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This

Helium refrigeration systems for super-conducting accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganni, V.

Many of the present day accelerators are based on superconducting technology which requires 4.5-K or 2-K helium refrigeration systems. These systems utilize superconducting radio frequency (SRF) cavities and/or superconducting magnets which are packaged into vacuum vessels known as cryo-modules (CM’s). Many of the present day accelerators are optimized to operate primarily at around 2-K, requiring specialized helium refrigeration systems which are cost intensive to produce and to operate. Some of the cryogenic refrigeration system design considerations for these challenging applications are discussed.

LHC: The Large Hadron Collider

ScienceCinema

Lincoln, Don

2018-01-16

The Large Hadron Collider (or LHC) is the world’s most powerful particle accelerator. In 2012, scientists used data taken by it to discover the Higgs boson, before pausing operations for upgrades and improvements. In the spring of 2015, the LHC will return to operations with 163% the energy it had before and with three times as many collisions per second. It’s essentially a new and improved version of itself. In this video, Fermilab’s Dr. Don Lincoln explains both some of the absolutely amazing scientific and engineering properties of this modern scientific wonder.

Molecular dynamics simulations of the diffusion and coalescence of helium in tungsten

NASA Astrophysics Data System (ADS)

Zhou, Y. L.; Wang, J.; Hou, Q.; Deng, A. H.

2014-03-01

Molecular dynamics (MD) simulations are performed on the diffusion and coalescence of helium in tungsten. A new method for determining the effective capture radii (ECRs) and the dissociation energies of helium-related defects is proposed in this work. It is observed that the ECR of an interstitial helium atom trapping helium interstitials (denoted as He-Hen, n = 1-3) decreases with increasing temperature, except for He-He2 at T < 400 K. The traditional view that the ECR is approximately equal to the lattice constant, which has been widely used in kinetic Monte Carlo (KMC) and rate theory (RT) models, is only valid in some cases. However, the ECR between an interstitial helium atom and a substitutional helium atom (denoted as He-HeV) always approximates the third nearest-neighbor tetrahedral positions of the HeV. The diffusion coefficients Dn for helium clusters are also investigated. He2 migrates more quickly than a single He atom does at T < 400 K, whereas the diffusion path of He2 changes at higher temperatures. Another counterintuitive observation is that D5 > D3 > D4 at T < 500 K, which can be attributed to the disordered structure of He5. The Arrhenius relation describes the diffusion of Hen well in the temperature range from 300 K to 550 K, whereas the diffusion is not a standard thermally activated process at higher temperatures. Taken together, these results help elucidate the initial stage of helium bubble formation in tungsten as well as the requirements of long-term evolution methods such as KMC or RT models.

Behavior of helium gas atoms and bubbles in low activation 9Cr martensitic steels

NASA Astrophysics Data System (ADS)

Hasegawa, Akira; Shiraishi, Haruki; Matsui, Hideki; Abe, Katsunori

1994-09-01

The behavior of helium-gas release from helium-implanted 9Cr martensitic steels (500 appm implanted at 873 K) during tensile testing at 873 K was studied. Modified 9Cr-1Mo, low-activation 9Cr-2W and 9Cr-0.5V were investigated. Cold-worked AISI 316 austenitic stainless steel was also investigated as a reference which was susceptible helium embrittlement at high temperature. A helium release peak was observed at the moment of rupture in all the specimens. The total quantity of helium released from these 9Cr steels was in the same range but smaller than that of 316CW steel. Helium gas in the 9Cr steels should be considered to remain in the matrix at their lath-packets even if deformed at 873 K. This is the reason why the martensitic steels have high resistance to helium embrittlement.

The excitation of helium resonance lines in solar flares

NASA Technical Reports Server (NTRS)

Porter, J. G.; Gebbie, K. B.; November, L. J.

1985-01-01

Helium resonance line intensities are calculated for a set of six flare models corresponding to two rates of heating and three widely varying incident fluxes of soft X-rays. The differing ionization and excitation equilibria produced by these models, the processes which dominate the various cases, and the predicted helium line spectra are examined. The line intensities and their ratios are compared with values derived from Skylab NRL spectroheliograms for a class M flare, thus determining which of these models most nearly represents the density vs temperature structure and soft X-ray flux in the flaring solar transition region, and the temperature and dominant mechanaism of formation of the helium line spectrum during a flare.

LHC collider phenomenology of minimal universal extra dimensions

NASA Astrophysics Data System (ADS)

Beuria, Jyotiranjan; Datta, AseshKrishna; Debnath, Dipsikha; Matchev, Konstantin T.

2018-05-01

We discuss the collider phenomenology of the model of Minimal Universal Extra Dimensions (MUED) at the Large hadron Collider (LHC). We derive analytical results for all relevant strong pair-production processes of two level 1 Kaluza-Klein partners and use them to validate and correct the existing MUED implementation in the fortran version of the PYTHIA event generator. We also develop a new implementation of the model in the C++ version of PYTHIA. We use our implementations in conjunction with the CHECKMATE package to derive the LHC bounds on MUED from a large number of published experimental analyses from Run 1 at the LHC.

BPM CALIBRATION INDEPENDENT LHC OPTICS CORRECTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

CALAGA,R.; TOMAS, R.; GIOVANNOZZI, M.

2007-06-25

The tight mechanical aperture for the LHC imposes severe constraints on both the beta and dispersion beating. Robust techniques to compensate these errors are critical for operation of high intensity beams in the LHC. We present simulations using realistic errors from magnet measurements and alignment tolerances in the presence of BPM noise. Correction reveals that the use of BPM calibration and model independent observables are key ingredients to accomplish optics correction. Experiments at RHIC to verify the algorithms for optics correction are also presented.

Relief as a Reward: Hedonic and Neural Responses to Safety from Pain

PubMed Central

Leknes, Siri; Lee, Michael; Berna, Chantal; Andersson, Jesper; Tracey, Irene

2011-01-01

Relief fits the definition of a reward. Unlike other reward types the pleasantness of relief depends on the violation of a negative expectation, yet this has not been investigated using neuroimaging approaches. We hypothesized that the degree of negative expectation depends on state (dread) and trait (pessimism) sensitivity. Of the brain regions that are involved in mediating pleasure, the nucleus accumbens also signals unexpected reward and positive prediction error. We hypothesized that accumbens activity reflects the level of negative expectation and subsequent pleasant relief. Using fMRI and two purpose-made tasks, we compared hedonic and BOLD responses to relief with responses during an appetitive reward task in 18 healthy volunteers. We expected some similarities in task responses, reflecting common neural substrates implicated across reward types. However, we also hypothesized that relief responses would differ from appetitive rewards in the nucleus accumbens, since only relief pleasantness depends on negative expectations. The results confirmed these hypotheses. Relief and appetitive reward task activity converged in the ventromedial prefrontal cortex, which also correlated with appetitive reward pleasantness ratings. In contrast, dread and pessimism scores correlated with relief but not with appetitive reward hedonics. Moreover, only relief pleasantness covaried with accumbens activation. Importantly, the accumbens signal appeared to specifically reflect individual differences in anticipation of the adverse event (dread, pessimism) but was uncorrelated to appetitive reward hedonics. In conclusion, relief differs from appetitive rewards due to its reliance on negative expectations, the violation of which is reflected in relief-related accumbens activation. PMID:21490964

31 CFR 306.112 - Type of relief granted.

Code of Federal Regulations, 2010 CFR

2010-07-01

... time relief is authorized using interest rate factors based on then current market yields on Treasury... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Type of relief granted. 306.112 Section 306.112 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL...

Experiments on the properties of superfluid helium in zero gravity

NASA Technical Reports Server (NTRS)

Mason, P.; Collins, D.; Petrac, D.; Yang, L.; Edeskuty, F.; Williamson, K.

1976-01-01

The paper describes a research program designed to study the behavior of superfluid liquid helium in low and zero gravity in order to determine the properties which are critically important to its use as a stored cryogen for cooling scientific instruments aboard spacecraft for periods up to several months. The experiment program consists of a series of flights of an experiment package on a free-fall trajectory both on an aircraft and on a rocket. The objectives are to study thickness of thin films of helium as a function of acceleration, heat transfer in thin films, heat transfer across copper-liquid helium interfaces, fluid dynamics of bulk helium in high and low accelerations and under various conditions of rotations, alternate methods of separation of liquid and vapor phases and of efficient venting of the vapor, and undesirable thermomechanical oscillations in the vent pipes. Preliminary results from aircraft tests are discussed.

Some properties of solid helium and helium nanoclusters using the effective HFD-like interaction potential: Adsorption and desorption inside carbon nanotube

NASA Astrophysics Data System (ADS)

Abbaspour, M.; Akbarzadeh, H.; Banihashemi, S. Z.; Sotoudeh, A.

2018-02-01

We have calculated the zero equation of state of solid helium using a two-body Hartree-Fock dispersion (HFD)-like potential from molecular dynamics (MD) simulation. To take many-body forces into account, our simple and accurate empirical expression is used with the HFD-like potential without requiring an expensive three-body calculation. This potential model also includes the quantum effects for helium at low temperatures. The results indicate that our effective HFD-like potential improves the prediction of the classical two-body results to get better agreement with experiment than many other two-body and three-body potentials of helium reported in the literature. We have also simulated the adsorption and desorption processes of the (He)55, (He)147, (He)309, (He)561, and (He)923 icosahedral nanoclusters confined into the different armchair and zigzag CNTs from 0 to 50 K using our effective model. We have observed an interesting phenomenon at 0 K for helium. The nanoclusters adsorb to the inner CNT wall as a melting process. But, the heavier noble gas clusters (such as Ne and Xe) show the different behavior than the He clusters. They form a multilayered solid structure into the CNT at zero temperature and adsorb into the inner wall of the CNT at higher temperatures. Our results for He clusters show that the absolute value of the adsorption energy increases as the size of the nanocluster increases. The desorption process begins at a certain temperature and represents itself by a jump in the configurational energy values. We have also investigated the structural and dynamical properties of the confined helium nanoclusters during the adsorption and desorption processes at different temperatures.

Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Yunteng; Zhang, Jie; Li, Yang

2015-08-15

We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He{sub 2}{sup +} and He{sub 4}{sup +}, which are signatures of superfluid helium droplets. Without ionizing any helium atoms, multiphoton non-resonant laser ionization of CCl{sub 4} doped in superfluid helium droplets at 266 nm generates complex cluster ions of dopant fragments with helium atoms, including (He){sub n}C{sup +}, (He){sub n}Cl{sup +}, and (He){sub n}CCl{sup +}. Usingmore » both methods, we have characterized our cryogenic pulsed valve—the Even-Lavie valve. We have observed a primary pulse with larger helium droplets traveling at a slower speed and a rebound pulse with smaller droplets at a faster speed. In addition, the pickup efficiency of dopant is higher for the primary pulse when the nozzle temperature is higher than 13 K, and the total time duration of the doped droplet pulse is only on the order of 20 μs. These results stress the importance of fast and easy characterization of the droplet beam for sensitive measurements such as electron diffraction of doped droplets.« less

Optimization of Helium Vessel Design for ILC Cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fratangelo, Enrico

2009-01-01

The ILC (International Linear Collider) is a proposed new major particle accelerator. It consists of two 20 km long linear accelerators colliding electrons and positrons at an energy exceeding 500 GeV, Achieving this collision energy while keeping reasonable accelerator dimensions requires the use of high electric field superconducting cavities as the main acceleration element. These cavities are operated at l.3 GHz inside an appropriate container (He vessel) at temperatures as low as 1.4 K using superfluid Helium as the refrigerating medium. The purpose of this thesis, in the context of the ILC R&D activities currently in progress at Fermilab (Fermimore » National Accelerator Laboratory), is the mechanical study of an ILC superconducting cavity and Helium vessel prototype. The main goals of these studies are the determination of the limiting working conditions of the whole He vessel assembly, the simulation of the manufacturing process of the cavity end-caps and the assessment of the Helium vessel's efficiency. In addition this thesis studies the requirements to certify the compliance with the ASME Code of the whole cavity/vessel assembly. Several Finite Elements Analyses were performed by the candidate himself in order to perform the studies listed above and described in detail in Chapters 4 through 8. ln particular the candidate has developed an improved procedure to obtain more accurate results with lower computational times. These procedures will be accurately described in the following chapters. After an introduction that briefly describes the Fennilab and in particular the Technical Division (where all the activities concerning with this thesis were developed), the first part of this thesis (Chapters 2 and 3) explains some of the main aspects of modem particle accelerators. Moreover it describes the most important particle accelerators working at the moment and the basic features of the ILC project. Chapter 4 describes all the activities that were done to

Helium-ion-induced human cataractogenesis

NASA Technical Reports Server (NTRS)

Blakely, E. A.; Daftari, I. K.; Meecham, W. J.; Alonso, L. C.; Collier, J. M.; Kroll, S. M.; Gillette, E. L.; Lee, A. C.; Lett, J. T.; Cox, A. B.

1994-01-01

Retrospective and ongoing analyses of clinical records from 347 primary intraocular melanoman patients treated with helium ions at Lawrence Berkeley Laboratory (LBL) will allow examination of the exposure-response data for human cataract; which is a complication of the therapy from incidental exposure of the lens. Direct particle beam traversal of at least a portion of the lens usually is unavoidable in treatment of posterior intraocular tumors. The precise treatment planned for each patient permits quantitative assessment of the lenticular dose and its radiation quality. We are reporting our preliminary results on the development of helium-ion-induced lens opacifications and cataracts in 54 of these patients who had 10% or less of their lens in the treatment field. We believe these studies will be relevant to estimating the human risk for cataract in space flight.

Calibrating the Helium Pressurization System for the Space Shuttle Liquid-Hydrogen Tank

NASA Technical Reports Server (NTRS)

2008-01-01

Analysis of the results from the STS-114 tanking tests and subsequent launch called into question existing thermal and mass models of helium pressurization of the liquid hydrogen tank. This hydrogen tank, which makes up the bottom two-thirds of the External Tank, is pressurized prior to launch to avoid cavitation in the Shuttle Main Engine pumps. At about 2 minutes prior to launch, the main vent valve is closed, and pressurized helium flows into the tank ullage space to achieve set point pressure. As the helium gas cools, its pressure drops, calling for additional helium. Subsequent helium flows are provided in short, timed pulses. The number of pulses is taken as a rough leak indicator. An analysis of thermal models by Marshall Space Flight Center showed considerable uncertainty in the pressure-versus-time behavior of the helium ullage space and the ability to predict the number of pulses normally expected. Kennedy Space Center proposed to calibrate the dime-sized orifice, which together with valves, controls the helium flow quantity (Figure 1). Pressure and temperature sensors were installed to provide upstream and downstream measurements necessary to compute flow rate based on the orifice discharge coefficient. An assessment of flow testing with helium indicated an extremely costly use of this critical resource. In order to reduce costs, we proposed removing the orifices from each Mobile Launcher Platform (MLP) and asking Colorado Engineering Experiment Station Inc. (CEESI) to calibrate the flow. CEESI has a high-pressure air flow system with traceable flow meters capable of handling the large flow rates. However, literature research indicated that square-edged orifices of small diameters often exhibit significant hysteresis and nonrepeatability in the vicinity of choked or sonic flow. Fortunately, the MLP orifices behaved relatively well in testing (Figure 2). Using curve fitting of the air-flow data, in conjunction with ASME orifice modeling equations, a

Design of superconducting corrector magnets for LHC

NASA Astrophysics Data System (ADS)

Baynham, D. E.; Coombs, R. C.; Ijspeert, A.; Perin, R.

1994-07-01

The Large Hadron Collider (LHC) will require a range of superconducting corrector magnets. This paper presents the design of sextupole and decapole corrector coils which will be included as spool pieces adjacent to each main ring dipole. The paper gives detailed 3D field computations of the coil configurations to meet LHC beam dynamics requirements. Coil protection within a long string environment is addressed and mechanical design outlines are presented.

Radiation Hard Silicon Particle Detectors for Phase-II LHC Trackers

NASA Astrophysics Data System (ADS)

Oblakowska-Mucha, A.

2017-02-01

The major LHC upgrade is planned after ten years of accelerator operation. It is foreseen to significantly increase the luminosity of the current machine up to 1035 cm-2s-1 and operate as the upcoming High Luminosity LHC (HL-LHC) . The major detectors upgrade, called the Phase-II Upgrade, is also planned, a main reason being the aging processes caused by severe particle radiation. Within the RD50 Collaboration, a large Research and Development program has been underway to develop silicon sensors with sufficient radiation tolerance for HL-LHC trackers. In this summary, several results obtained during the testing of the devices after irradiation to HL-LHC levels are presented. Among the studied structures, one can find advanced sensors types like 3D silicon detectors, High-Voltage CMOS technologies, or sensors with intrinsic gain (LGAD). Based on these results, the RD50 Collaboration gives recommendation for the silicon detectors to be used in the detector upgrade.

Konstantinov effect in helium II

NASA Astrophysics Data System (ADS)

Melnikovsky, L. A.

2008-04-01

The reflection of first and second sound waves by a rigid flat wall in helium II is considered. A nontrivial dependence of the reflection coefficients on the angle of incidence is obtained. Sound conversion is predicted at oblique incidence.

46 CFR 154.517 - Piping: Liquid pressure relief.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Piping: Liquid pressure relief. 154.517 Section 154.517... and Process Piping Systems § 154.517 Piping: Liquid pressure relief. The cargo loading and discharge crossover headers, cargo hoses, and cargo loading arms must have means to relieve cargo pressure and to...

46 CFR 154.517 - Piping: Liquid pressure relief.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Piping: Liquid pressure relief. 154.517 Section 154.517... and Process Piping Systems § 154.517 Piping: Liquid pressure relief. The cargo loading and discharge crossover headers, cargo hoses, and cargo loading arms must have means to relieve cargo pressure and to...

46 CFR 154.517 - Piping: Liquid pressure relief.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Piping: Liquid pressure relief. 154.517 Section 154.517... and Process Piping Systems § 154.517 Piping: Liquid pressure relief. The cargo loading and discharge crossover headers, cargo hoses, and cargo loading arms must have means to relieve cargo pressure and to...

46 CFR 154.517 - Piping: Liquid pressure relief.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Piping: Liquid pressure relief. 154.517 Section 154.517... and Process Piping Systems § 154.517 Piping: Liquid pressure relief. The cargo loading and discharge crossover headers, cargo hoses, and cargo loading arms must have means to relieve cargo pressure and to...

46 CFR 154.517 - Piping: Liquid pressure relief.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Piping: Liquid pressure relief. 154.517 Section 154.517... and Process Piping Systems § 154.517 Piping: Liquid pressure relief. The cargo loading and discharge crossover headers, cargo hoses, and cargo loading arms must have means to relieve cargo pressure and to...

Solar flares and solar wind helium enrichments - July 1965-July 1967.

NASA Technical Reports Server (NTRS)

Hirshberg, J.; Bame, S. J.; Robbins, D. E.

1972-01-01

It has previously been suggested that the very high relative abundances of helium occasionally observed in the solar wind mark the plasma accelerated by major solar flares. To confirm this hypothesis, we have studied the 43 spectra with He/H greater than 15% that were observed among 10,300 spectra collected by Vela 3 between July 1965-July 1967. Six new flare-enhancement events are discussed in this paper. It is concluded that the association of helium enhancements with major flares is real, nonrandom, and very strong. With this study, there are 12 cases of reliable associations between helium enhancements and flares reported in the literature. The general characteristics of these events are discussed. It is found that the flares are typically large and bright (2B or 3B), often they produce cosmic ray protons, and they are widely distributed in solar longitude. A qualitative discussion of some of the possibilities for the source of helium enhanced plasma is presented. It is suggested that the helium enriched plasma may be the piston producing the shock causing the Type II radio emission.

Feasibility study for long lifetime helium dewar

NASA Technical Reports Server (NTRS)

Parmley, R. T.

1981-01-01

A feasible concept for a launchable three year lifetime helium dewar was investigted. Current helium dewar designs were examined to see where the largest potential reductions in parasitic heat loads can be made. The study was also devoted to examining support concepts. The support concept chosen, a passive orbital disconnect strut (PODS), has an orbital support conductance that is lower by more than an order of magnitude over current tension band supports. This lower support conductance cuts the total dewar weight in half for the same three year life time requirements. Effort was also concentrated on efficient wire feed through designs and vapor cooling of the multilayer insulation, supports, wire feed throughs and plumbing penetrations. A single stage helium dewar vs. dual stage dewars with a guard cryogen of nitrogen or neon was examined. The single stage dewar concept was selected. Different support concepts were analyzed from which the PODS support concepts was chosen. A preliminary design of the dewar was thermally and structurally analyzed and laid out including system weights, thermal performance and performance sensitivities.

On the LHC sensitivity for non-thermalised hidden sectors

NASA Astrophysics Data System (ADS)

Kahlhoefer, Felix

2018-04-01

We show under rather general assumptions that hidden sectors that never reach thermal equilibrium in the early Universe are also inaccessible for the LHC. In other words, any particle that can be produced at the LHC must either have been in thermal equilibrium with the Standard Model at some point or must be produced via the decays of another hidden sector particle that has been in thermal equilibrium. To reach this conclusion, we parametrise the cross section connecting the Standard Model to the hidden sector in a very general way and use methods from linear programming to calculate the largest possible number of LHC events compatible with the requirement of non-thermalisation. We find that even the HL-LHC cannot possibly produce more than a few events with energy above 10 GeV involving states from a non-thermalised hidden sector.

Lunar exospheric helium observations of LRO/LAMP coordinated with ARTEMIS

NASA Astrophysics Data System (ADS)

Grava, C.; Retherford, K. D.; Hurley, D. M.; Feldman, P. D.; Gladstone, G. R.; Greathouse, T. K.; Cook, J. C.; Stern, S. A.; Pryor, W. R.; Halekas, J. S.; Kaufmann, D. E.

2016-07-01

We present results from Lunar Reconnaissance Orbiter's (LRO) UV spectrograph LAMP (Lyman-Alpha Mapping Project) campaign to study the lunar atmosphere. Several off-nadir maneuvers (lateral rolls) were performed to search for resonantly scattering species, increasing the illuminated line-of-sight (and hence the signal from atoms resonantly scattering the solar photons) compared to previously reported LAMP's "twilight observations" (Cook, J.C., Stern, S.A. [2014]. Icarus 236, 48-55). Helium was the only element distinguishable on a daily basis, and we present latitudinal profiles of its line-of-sight column density in December 2013. We compared the helium line-of-sight column densities with solar wind alpha particle fluxes measured from the ARTEMIS (Acceleration, Reconnection, Turbulence, & Electrodynamics of Moon's Interaction with the Sun) twin spacecraft. Our data show a correlation with the solar wind alpha particle flux, confirming that the solar wind is the main source of the lunar helium. We also support the finding by Benna et al. (Benna, M. et al. [2015]. Geophys. Res. Lett. 42, 3723-3729) and Hurley et al. (Hurley, D.M. et al. [2015]. Icarus, this issue), that a non-zero contribution from endogenic helium, coming from radioactive decay of 232Th and 238U, is present. Moreover, our results suggest that not all of the incident alpha particles are converted to thermalized helium, allowing for a non-negligible fraction to escape as suprathermal helium or simply backscattered from the lunar surface. We compare LAMP-derived helium surface density with the one recorded by the mass spectrometer LACE (Lunar Atmospheric Composition Experiment) deployed on the lunar surface during the Apollo 17 mission, finding good agreement between the two measurements. The LRO/LAMP roll observations presented here are in agreement with the most recent lunar exospheric helium model (Hurley, D.M. et al. [2015]. Icarus, this issue) around mid- to high-latitudes (50-70°) regardless of

Source and movement of helium in the eastern Morongo groundwater Basin: The influence of regional tectonics on crustal and mantle helium fluxes

USGS Publications Warehouse

Kulongoski, J.T.; Hilton, David R.; Izbicki, J.A.

2005-01-01

We assess the role of fracturing and seismicity on fluid-driven mass transport of helium using groundwaters from the eastern Morongo Basin (EMB), California, USA. The EMB, located ???200 km east of Los Angeles, lies within a tectonically active region known as the Eastern California Shear Zone that exhibits both strike-slip and extensional deformation. Helium concentrations from 27 groundwaters range from 0.97 to 253.7 ?? 10-7 cm3 STP g-1 H2O, with corresponding 3He/4He ratios falling between 1.0 and 0.26 RA (where RA is the 3He/4He ratio of air). All groundwaters had helium isotope ratios significantly higher than the crustal production value of ???0.02 RA. Dissolved helium concentrations were resolved into components associated with solubility equilibration, air entrainment, in situ production within the aquifer, and extraneous fluxes (both crustal and mantle derived). All samples contained a mantle helium-3 (3Hem) flux in the range of 4.5 to 1351 ?? 10-14 cm3 STP 3He cm-2 yr-1 and a crustal flux (J0) between 0.03 and 300 ?? 10-7 cm3 STP 4He cm-2 yr-1. Groundwaters from the eastern part of the basin contained significantly higher 3Hem and deep crustal helium-4 (4Hedc) concentrations than other areas, suggesting a localized source for these components. 4Hedc and 3Hem are strongly correlated, and are associated with faults in the basin. A shallow thermal anomaly in a >3,000 m deep graben in the eastern basin suggests upflow of fluids through active faults associated with extensional tectonics. Regional tectonics appears to drive large scale crustal fluid transport, whereas episodic hydrofracturing provides an effective mechanism for mantle-crust volatile transport identified by variability in the magnitude of degassing fluxes (3Hem and J0) across the basin. Copyright ?? 2005 Elsevier Ltd.

Chemical reactions studied at ultra-low temperature in liquid helium clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huisken, Friedrich; Krasnokutski, Serge A.

Low-temperature reaction rates are important ingredients for astrophysical reaction networks modeling the formation of interstellar matter in molecular clouds. Unfortunately, such data is difficult to obtain by experimental means. In an attempt to study low-temperature reactions of astrophysical interest, we have investigated relevant reactions at ultralow temperature in liquid helium droplets. Being prepared by supersonic expansion of helium gas at high pressure through a nozzle into a vacuum, large helium clusters in the form of liquid droplets constitute nano-sized reaction vessels for the study of chemical reactions at ultra-low temperature. If the normal isotope {sup 4}He is used, the heliummore » droplets are superfluid and characterized by a constant temperature of 0.37 K. Here we present results obtained for Mg, Al, and Si reacting with O{sub 2}. Mass spectrometry was employed to characterize the reaction products. As it may be difficult to distinguish between reactions occurring in the helium droplets before they are ionized and ion-molecule reactions taking place after the ionization, additional techniques were applied to ensure that the reactions actually occurred in the helium droplets. This information was provided by measuring the chemiluminescence light emitted by the products, the evaporation of helium atoms by the release of the reaction heat, or by laser-spectroscopic identification of the reactants and products.« less

Performance Testing of Jefferson Lab 12 GeV Helium Screw Compressors

DOE PAGES

Knudsen, P.; Ganni, V.; Dixon, K.; ...

2015-08-10

Oil injected screw compressors have essentially superseded all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, reliability, minimal vibration, and capability of handling helium's high heat of compression. At the present state of compressor system designs for helium refrigeration systems, typically two-thirds of the lost input power is due to the compression system. It is important to understand the isothermal and volumetric efficiencies of these machines to help properly design the compression system to match the refrigeration process. It is also important to identify those primary compressor skid exergetic loss mechanisms which maymore » be reduced, thereby offering the possibility of significantly reducing the input power to helium refrigeration processes which are extremely energy intensive. This paper summarizes the results collected during the commissioning of the new compressor system for Jefferson Lab's (JLab's) 12 GeV upgrade. The compressor skid packages were designed by JLab and built to print by industry. They incorporate a number of modifications not typical of helium screw compressor packages and most importantly allow a very wide range of operation so that JLab's patented Floating Pressure Process can be fully utilized. This paper also summarizes key features of the skid design that allow this process and facilitate the maintenance and reliability of these helium compressor systems.« less

Performance Testing of Jefferson Lab 12 GeV Helium Screw Compressors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knudsen, P.; Ganni, V.; Dixon, K.

Oil injected screw compressors have essentially superseded all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, reliability, minimal vibration, and capability of handling helium's high heat of compression. At the present state of compressor system designs for helium refrigeration systems, typically two-thirds of the lost input power is due to the compression system. It is important to understand the isothermal and volumetric efficiencies of these machines to help properly design the compression system to match the refrigeration process. It is also important to identify those primary compressor skid exergetic loss mechanisms which maymore » be reduced, thereby offering the possibility of significantly reducing the input power to helium refrigeration processes which are extremely energy intensive. This paper summarizes the results collected during the commissioning of the new compressor system for Jefferson Lab's (JLab's) 12 GeV upgrade. The compressor skid packages were designed by JLab and built to print by industry. They incorporate a number of modifications not typical of helium screw compressor packages and most importantly allow a very wide range of operation so that JLab's patented Floating Pressure Process can be fully utilized. This paper also summarizes key features of the skid design that allow this process and facilitate the maintenance and reliability of these helium compressor systems.« less

Charged-particle multiplicity at LHC energies

ScienceCinema

Grosse-Oetringhaus, Jan Fiete

2018-05-24

The talk presents the measurement of the pseudorapidity density and the multiplicity distribution with ALICE at the achieved LHC energies of 0.9 and 2.36 TeV.An overview about multiplicity measurements prior to LHC is given and the related theoretical concepts are briefly discussed.The analysis procedure is presented and the systematic uncertainties are detailed. The applied acceptance corrections and the treatment of diffraction are discussed.The results are compared with model predictions. The validity of KNO scaling in restricted phase space regions is revisited. 

49 CFR 179.500-12 - Pressure relief devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure relief devices. 179.500-12 Section 179... TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure...

Cost Analysis of NEDU’s Helium Reclaimer.

DTIC Science & Technology

1981-09-01

T ITLE (and Subtitle) S . TYPE OF REPORT 6 PERIOD COVERED COST ANALYSIS OF NEDU’S HELIUM RECLAIMER . Survey 6 . PERFORMING ORG. REPORT NUMSER 7...telephone conversation). 5. Charles T. Horngren , "Introduction tu Management Accounting " Fourth Edition. 3 . .4m mmnssmmlm~ • FIGURE 1 PRESENT, FUTURE AND...FEET COST OF PERIODIC MAINTENANCE OF HELIUM ELECTRIiC COST COST OF TOTAL RECLAIMED POWER NEW COST PRESENT WORTH YEAR N PER YEAR ( S /1000 FT

Particle production at RHIC and LHC energies

NASA Astrophysics Data System (ADS)

Tawfik, A.; Gamal, E.; Shalaby, A. G.

2015-07-01

The production of pion, kaon and proton was measured in Pb-Pb collisions at nucleus-nucleus center-of-mass energy sNN = 2.76TeV by the ALICE experiment at Large Hadron Collider (LHC). The particle ratios of these species compared to the RHIC measurements are confronted to the hadron resonance gas (HRG) model and to simulations based on the event generators PYTHIA 6.4.21 and HIJING 1.36. It is found that the homogeneous particle-antiparticle ratios (same species) are fully reproducible by means of HRG and partly by PYTHIA 6.4.21 and HIJING 1.36. The mixed kaon-pion and proton-pion ratios measured at RHIC and LHC energies seem to be reproducible by the HRG model. On the other hand, the strange abundances are underestimated in both event generators. This might be originated to strangeness suppression in the event generators and/or possible strangeness enhancement in the experimental data. It is apparent that the values of kaon-pion ratios are not sensitive to the huge increase of sNN from 200 (RHIC) to 2760 GeV (LHC). We conclude that the ratios of produced particle at LHC seem not depending on the system size.

Test program, helium II orbital resupply coupling

NASA Technical Reports Server (NTRS)

Hyatt, William S.

1991-01-01

The full scope of this program was to have included development tests, design and production of custom test equipment and acceptance and qualification testing of prototype and protoflight coupling hardware. This program was performed by Ball Aerospace Systems Division, Boulder, Colorado until its premature termination in May 1991. Development tests were performed on cryogenic face seals and flow control devices at superfluid helium (He II) conditions. Special equipment was developed to allow quantified leak detection at large leak rates up to 8.4 x 10(exp -4) SCCS. Two major fixtures were developed and characterized: The Cryogenic Test Fixture (CTF) and the Thermal Mismatch Fixture (Glovebox). The CTF allows the coupling hardware to be filled with liquid nitrogen (LN2), liquid helium (LHe) or sub-cooled liquid helium when hardware flow control valves are either open or closed. Heat leak measurements, internal and external helium leakage measurements, cryogenic proof pressure tests and external load applications are performed in this fixture. Special reusable MLI closures were developed to provide repeatable installations in the CTF. The Thermal Mismatch Fixture allows all design configurations of coupling hardware to be engaged and disengaged while measuring applied forces and torques. Any two hardware components may be individually thermally preconditioned within the range of 117 deg K to 350 deg K prior to engage/disengage cycling. This verifies dimensional compatibility and operation when thermally mismatched. A clean, dry GN2 atmosphere is maintained in the fixture at all times. The first shipset of hardware was received, inspected and cycled at room temperature just prior to program termination.

Building relations with women's organisations in relief work.

PubMed

Gell, F

1997-02-01

An Oxfam Emergency Team arrived in Ingushetia in the Northern Caucasus region of the former Soviet Union in August 1996 to set up a program of shelter, rehabilitation, and relief in response to the large influx of people displaced by conflicts in the neighboring republics of Chechnya and North Ossetia. The team was also tasked with contacting community organizations such as women's groups and developing a relationship with them through joint relief work. The Chechen population was comprised of mainly women, children, and the elderly. The internally displaced population of 100,000 people is now scattered throughout the republic in collective centers and host families. Small committees of women were formed to help identify the most vulnerable residents and to distribute winter clothing. It was found during the relief work that fledgling women's groups are establishing themselves as vehicles for change, increasingly open to work with and learn from international organizations such as Oxfam. The Chechen branch of the Union of North Caucasian Women and the Ingushetian ALMOS played leading roles in peacemaking, human rights observance, and humanitarian relief.

The adsorption of helium atoms on small cationic gold clusters.

PubMed

Goulart, Marcelo; Gatchell, Michael; Kranabetter, Lorenz; Kuhn, Martin; Martini, Paul; Gitzl, Norbert; Rainer, Manuel; Postler, Johannes; Scheier, Paul; Ellis, Andrew M

2018-04-04

Adducts formed between small gold cluster cations and helium atoms are reported for the first time. These binary ions, Aun+Hem, were produced by electron ionization of helium nanodroplets doped with neutral gold clusters and were detected using mass spectrometry. For a given value of n, the distribution of ions as a function of the number of added helium atoms, m, has been recorded. Peaks with anomalously high intensities, corresponding to so-called magic number ions, are identified and interpreted in terms of the geometric structures of the underlying Aun+ ions. These features can be accounted for by planar structures for Aun+ ions with n ≤ 7, with the addition of helium having no significant effect on the structures of the underlying gold cluster ions. According to ion mobility studies and some theoretical predictions, a 3-D structure is expected for Au8+. However, the findings for Au8+ in this work are more consistent with a planar structure.

THE EFFECTS OF CURVATURE AND EXPANSION ON HELIUM DETONATIONS ON WHITE DWARF SURFACES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Kevin; Bildsten, Lars; Townsley, Dean M.

2013-10-20

Accreted helium layers on white dwarfs have been highlighted for many decades as a possible site for a detonation triggered by a thermonuclear runaway. In this paper, we find the minimum helium layer thickness that will sustain a steady laterally propagating detonation and show that it depends on the density and composition of the helium layer, specifically {sup 12}C and {sup 16}O. Detonations in these thin helium layers have speeds slower than the Chapman-Jouget (CJ) speed from complete helium burning, v{sub CJ} = 1.5 × 10{sup 9} cm s{sup –1}. Though gravitationally unbound, the ashes still have unburned helium (≈80%more » in the thinnest cases) and only reach up to heavy elements such as {sup 40}Ca, {sup 44}Ti, {sup 48}Cr, and {sup 52}Fe. It is rare for these thin shells to generate large amounts of {sup 56}Ni. We also find a new set of solutions that can propagate in even thinner helium layers when {sup 16}O is present at a minimum mass fraction of ≈0.07. Driven by energy release from α captures on {sup 16}O and subsequent elements, these slow detonations only create ashes up to {sup 28}Si in the outer detonated He shell. We close by discussing how the unbound helium burning ashes may create faint and fast 'Ia' supernovae as well as events with virtually no radioactivity, and speculate on how the slower helium detonation velocities impact the off-center ignition of a carbon detonation that could cause a Type Ia supernova in the double detonation scenario.« less

Development of silicon detectors for Beam Loss Monitoring at HL-LHC

NASA Astrophysics Data System (ADS)

Verbitskaya, E.; Eremin, V.; Zabrodskii, A.; Bogdanov, A.; Shepelev, A.; Dehning, B.; Bartosik, M. R.; Alexopoulos, A.; Glaser, M.; Ravotti, F.; Sapinski, M.; Härkönen, J.; Egorov, N.; Galkin, A.

2017-03-01

Silicon detectors were proposed as novel Beam Loss Monitors (BLM) for the control of the radiation environment in the vicinity of the superconductive magnets of the High-Luminosity Large Hadron Collider. The present work is aimed at enhancing the BLM sensitivity and therefore the capability of triggering the beam abort system before a critical radiation load hits the superconductive coils. We report here the results of three in situ irradiation tests of Si detectors carried out at the CERN PS at 1.9-4.2 K. The main experimental result is that all silicon detectors survived irradiation up to 1.22× 1016 p/cm2. The third test, focused on the detailed characterization of the detectors with standard (300 μm) and reduced (100 μm) thicknesses, showed only a marginal difference in the sensitivity of thinned detectors in the entire fluence range and a smaller rate of signal degradation that promotes their use as BLMs. The irradiation campaigns produced new information on radiation damage and carrier transport in Si detectors irradiated at the temperatures of 1.9-4.2 K. The results were encouraging and permitted to initiate the production of the first BLM prototype modules which were installed at the end of the vessel containing the superconductive coil of a LHC magnet immersed in superfluid helium to be able to test the silicon detectors in real operational conditions.

What a Relief: Using Paper Relief Sculpture to Teach Topographic Map Skills

ERIC Educational Resources Information Center

Price, Kelly

2005-01-01

While the struggle persists in science classes to help students visualize in three dimensions, art classes are creating unique sculptures out of paper that produce three-dimensional displays from two-dimensional resources. The translation of paper relief sculpting from the art classroom to the science classroom adds dimension to the teaching of…

43 CFR 3195.30 - How do I apply to become a Federal helium supplier?

Code of Federal Regulations, 2011 CFR

2011-10-01

... Federal helium buyers; and (3) A satisfactory record of performance in the distribution of helium or other compressed gases. (b) You must fill out and execute BLM's In-Kind Crude Helium Sales Contract and submit it...

30 CFR 203.80 - When can I get royalty relief if I am not eligible for royalty relief under other sections in the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... ROYALTY RATES OCS Oil, Gas, and Sulfur General Royalty Relief for Pre-Act Deep Water Leases and for... you may apply for royalty relief apart from our programs for end-of-life leases or for pre-Act deep...

Characterization of high flux magnetized helium plasma in SCU-PSI linear device

NASA Astrophysics Data System (ADS)

Xiaochun, MA; Xiaogang, CAO; Lei, HAN; Zhiyan, ZHANG; Jianjun, WEI; Fujun, GOU

2018-02-01

A high-flux linear plasma device in Sichuan University plasma-surface interaction (SCU-PSI) based on a cascaded arc source has been established to simulate the interactions between helium and hydrogen plasma with the plasma-facing components in fusion reactors. In this paper, the helium plasma has been characterized by a double-pin Langmuir probe. The results show that the stable helium plasma beam with a diameter of 26 mm was constrained very well at a magnetic field strength of 0.3 T. The core density and ion flux of helium plasma have a strong dependence on the applied current, magnetic field strength and gas flow rate. It could reach an electron density of 1.2 × 1019 m-3 and helium ion flux of 3.2 × 1022 m-2 s-1, with a gas flow rate of 4 standard liter per minute, magnetic field strength of 0.2 T and input power of 11 kW. With the addition of -80 V applied to the target to increase the helium ion energy and the exposure time of 2 h, the flat top temperature reached about 530 °C. The different sizes of nanostructured fuzz on irradiated tungsten and molybdenum samples surfaces under the bombardment of helium ions were observed by scanning electron microscopy. These results measured in the SCU-PSI linear device provide a reference for International Thermonuclear Experimental Reactor related PSI research.

Dynamics of Superfluid Helium in Low-Gravity

NASA Technical Reports Server (NTRS)

Frank, David J.

1997-01-01

This report summarizes the work performed under a contract entitled 'Dynamics of Superfluid Helium in Low Gravity'. This project performed verification tests, over a wide range of accelerations of two Computational Fluid Dynamics (CFD) codes of which one incorporates the two-fluid model of superfluid helium (SFHe). Helium was first liquefied in 1908 and not until the 1930s were the properties of helium below 2.2 K observed sufficiently to realize that it did not obey the ordinary physical laws of physics as applied to ordinary liquids. The term superfluidity became associated with these unique observations. The low temperature of SFHe and it's temperature unifonrmity have made it a significant cryogenic coolant for use in space applications in astronomical observations with infrared sensors and in low temperature physics. Superfluid helium has been used in instruments such as the Shuttle Infrared Astronomy Telescope (IRT), the Infrared Astronomy Satellite (IRAS), the Cosmic Background Observatory (COBE), and the Infrared Satellite Observatory (ISO). It is also used in the Space Infrared Telescope (SIRTF), Relativity Mission Satellite formally called Gravity Probe-B (GP-B), and the Test of the Equivalence Principle (STEP) presently under development. For GP-B and STEP, the use of SFHE is used to cool Superconducting Quantum Interference Detectors (SQUIDS) among other parts of the instruments. The Superfluid Helium On-Orbit Transfer (SHOOT) experiment flown in the Shuttle studied the behavior of SFHE. This experiment attempted to get low-gravity slosh data, however, the main emphasis was to study the low-gravity transfer of SFHE from tank to tank. These instruments carried tanks of SFHE of a few hundred liters to 2500 liters. The capability of modeling the behavior of SFHE is important to spacecraft control engineers who must design systems that can overcome disturbances created by the movement of the fluid. In addition instruments such as GP-B and STEP are very

Effects of strong laser fields on hadronic helium atoms

NASA Astrophysics Data System (ADS)

Lee, Han-Chieh; Jiang, Tsin-Fu

2015-12-01

The metastable hadronic helium atoms in microseconds lifetime are available in laboratory, and two-photon spectroscopy was reported recently. This exotic helium atom has an electron in the ground state and a negative hadron rotating around the helium nucleus. We theoretically study the excitation on hadronic helium by femtosecond pulse and elucidate the influence of moleculelike structure and rotation behavior on the photoelectron spectra and high-order harmonic generation. Because of the moleculelike structure, the electronic ground state consists of several angular orbitals. These angular orbitals can enhance photoelectron spectra at high energies, and also influence the harmonic generation spectra considerably. In particular, the harmonic spectra can occur at even harmonic orders because of the transition between these angular orbitals and continuum states. On the other side, the rotation behavior of hadron can induce a frequency shift in the harmonic spectra. The magnitude of the frequency shift depends on the orbiting speed of the hadron, which is considerable because the rotation period is in a few femtoseconds, a time scale that is comparable to that of infrared laser and is feasible in current laser experiments.

Helium bubbles aggravated defects production in self-irradiated copper

NASA Astrophysics Data System (ADS)

Wu, FengChao; Zhu, YinBo; Wu, Qiang; Li, XinZhu; Wang, Pei; Wu, HengAn

2017-12-01

Under the environment of high radiation, materials used in fission and fusion reactors will internally accumulate numerous lattice defects and bubbles. With extensive studies focused on bubble resolution under irradiation, the mutually effects between helium bubbles and displacement cascades in irradiated materials remain unaddressed. Therefore, the defects production and microstructure evolution under self-irradiation events in vicinity of helium bubbles are investigated by preforming large scale molecular dynamics simulations in single-crystal copper. When subjected to displacement cascades, distinguished bubble resolution categories dependent on bubble size are observed. With the existence of bubbles, radiation damage is aggravated with the increasing bubble size, represented as the promotion of point defects and dislocations. The atomic mechanisms of heterogeneous dislocation structures are attributed to different helium-vacancy cluster modes, transforming from the resolved gas trapped with vacancies to the biased absorption of vacancies by the over-pressured bubble. In both cases, helium impedes the recombination of point defects, leading to the accelerated formation of interstitial loops. The results and insight obtained here might contribute to understand the underlying mechanism of transmutant solute on the long-term evolution of irradiated materials.

hhjj production at the LHC

DOE PAGES

Dolan, Matthew J.; Englert, Christoph; Greiner, Nicolas; ...

2015-08-25

The search for di-Higgs production at the LHC in order to set limits on the Higgs trilinear coupling and constraints on new physics is one of the main motivations for the LHC high-luminosity phase. Recent experimental analyses suggest that such analyses will only be successful if information from a range of channels is included. We therefore investigate di-Higgs production in association with two hadronic jets and give a detailed discussion of both the gluon- and the weak boson-fusion (WBF) contributions, with a particular emphasis on the phenomenology with modified Higgs trilinear and quartic gauge couplings. We perform a detailed investigationmore » of the full hadronic final state and find that hhjj production should add sensitivity to a di-Higgs search combination at the HL-LHC with 3 ab -1. Since the WBF and GF contributions are sensitive to different sources of physics beyond the Standard Model, we devise search strategies to disentangle and isolate these production modes. In addition, while gluon fusion remains non-negligible in WBF-type selections, sizeable new physics contributions to the latter can still be constrained. As an example of the latter point we investigate the sensitivity that can be obtained for a measurement of the quartic Higgs–gauge boson couplings.« less

12 CFR 303.248 - Truth in Lending Act-Relief from reimbursement.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Truth in Lending Act-Relief from reimbursement... PRACTICE FILING PROCEDURES Other Filings § 303.248 Truth in Lending Act—Relief from reimbursement. (a) Scope. This section applies to requests for relief from reimbursement pursuant to the Truth in Lending...

LHC searches for dark sector showers

NASA Astrophysics Data System (ADS)

Cohen, Timothy; Lisanti, Mariangela; Lou, Hou Keong; Mishra-Sharma, Siddharth

2017-11-01

This paper proposes a new search program for dark sector parton showers at the Large Hadron Collider (LHC). These signatures arise in theories characterized by strong dynamics in a hidden sector, such as Hidden Valley models. A dark parton shower can be composed of both invisible dark matter particles as well as dark sector states that decay to Standard Model particles via a portal. The focus here is on the specific case of `semi-visible jets,' jet-like collider objects where the visible states in the shower are Standard Model hadrons. We present a Simplified Model-like parametrization for the LHC observables and propose targeted search strategies for regions of parameter space that are not covered by existing analyses. Following the `mono- X' literature, the portal is modeled using either an effective field theoretic contact operator approach or with one of two ultraviolet completions; sensitivity projections are provided for all three cases. We additionally highlight that the LHC has a unique advantage over direct detection experiments in the search for this class of dark matter theories.

Superfluid helium leak sealant study

NASA Technical Reports Server (NTRS)

Vorreiter, J. W.

1981-01-01

Twenty-one leak specimens were fabricated in the ends of stainless steel and aluminum tubes. Eighteen of these tubes were coated with a copolymer material to seal the leak. The other three specimens were left uncoated and served as control specimens. All 21 tubes were cold shocked in liquid helium 50 times and then the leak rate was measured while the tubes were submerged in superfluid helium at 1.7 K. During the cold shocks two of the coated specimens were mechanically damaged and eliminated from the test program. Of the remaining 16 coated specimens one suffered a total coating failure and resulting high leak rate. Another three of the coated specimens suffered partial coating failures. The leak rates of the uncoated specimens were also measured and reported. The significance of various leak rates is discussed in view of the infrared astronomical satellite (IRAS) Dewar performance.

Dramatic reduction of void swelling by helium in ion-irradiated high purity α-iron

DOE PAGES

Bhattacharya, Arunodaya; Meslin, Estelle; Henry, Jean; ...

2018-04-11

Effect of helium on void swelling was studied in high-purity α-iron, irradiated using energetic self-ions to 157 displacements per atom (dpa) at 773 K, with and without helium co-implantation up to 17 atomic parts-per-million (appm) He/dpa. Helium is known to enhance cavity formation in metals in irradiation environments, leading to early void swelling onset. In this study, microstructure characterization by transmission electron microscopy revealed compelling evidence of dramatic swelling reduction by helium co-implantation, achieved primarily by cavity size reduction. In conclusion, a comprehensive understanding of helium induced cavity microstructure development is discussed using sink strength ratios of dislocations and cavities.

Gas-blowout control by water injection through relief wells: a theoretical analysis. [Injection of water into the formation through relief wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lehner, F.; Williamson, A.S.

1974-08-01

Koninklijke/Shell Exploratie en Produktie Laboratorium in The Netherlands suggests bringing a gas blowout under control by injecting water into the formation through relief wells. By avoiding direct contact between relief well and blowout well, this technique reduces the inflow of gas by creating sufficient back pressure in the formation itself. The mechanics of the technique are considered.

Helium liquefaction plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toscano, W.M.

1981-05-19

In a helium liquefaction plant, a compressor includes first, second and third stages and a precooling section includes first, second and third turboexpanders in series between high and low pressure lines of a heat exchanger. A portion of the medium pressure gas at the output of the second turboexpander is directed back through the heat exchanger and mixed with the output of the first compressor stage. The third turboexpander is positioned between the medium and low pressure lines.

Excitation of multiple surface-plasmon-polariton waves using a compound surface-relief grating

NASA Astrophysics Data System (ADS)

Faryad, Muhammad; Lakhtakia, Akhlesh

2012-01-01

The excitation of multiple surface-plasmon-polariton waves, all of the same frequency but different polarization states, phase speeds, spatial profiles and degrees of localization, by a compound surface-relief grating formed by a metal and a rugate filter, both of finite thickness, was studied using the rigorous coupled-wave approach. Each period of the compound surface-relief grating was chosen to have an integral number of periods of two different simple surface-relief gratings. The excitation of different SPP waves was inferred from the absorptance peaks that were independent of the thickness of the rugate filter. The excitation of each SPP wave could be attributed to either a simple surface-relief grating present in the compound surface-relief grating or to the compound surface-relief grating itself. However, the excitation of SPP waves was found to be less efficient with the compound surface-relief grating than with a simple surface-relief grating.

LHC Computing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lincoln, Don

The LHC is the world’s highest energy particle accelerator and scientists use it to record an unprecedented amount of data. This data is recorded in electronic format and it requires an enormous computational infrastructure to convert the raw data into conclusions about the fundamental rules that govern matter. In this video, Fermilab’s Dr. Don Lincoln gives us a sense of just how much data is involved and the incredible computer resources that makes it all possible.

Study of helium embrittlement in boron doped EUROFER97 steels

NASA Astrophysics Data System (ADS)

Gaganidze, E.; Petersen, C.; Aktaa, J.

2009-04-01

To simulate helium effects in Reduced Activation Ferritic/Martensitic steels, experimental heats ADS2, ADS3 and ADS4 with the basic composition of EUROFER97 (9%Cr-WVTa) were doped with different contents of natural boron and separated 10B-isotope (0.008-0.112 wt.%) and irradiated in High Flux Reactor (HFR) Petten up to 16.3 dpa at 250-450 °C and in Bor-60 fast reactor in Dimitrovgrad up to 31.8 dpa at 332-338 °C. The embrittlement and hardening are investigated by instrumented Charpy-V tests with subsize specimens. Complete burn-up of 10B isotope under neutron irradiation in HFR Petten led to generation of 84, 432 and 5580 appm He and partial boron-to-helium transformation in Bor-60 led to generation of 9, 46, 880 appm He in ADS2, ADS3 and ADS4 heats, respectively. At low irradiation temperatures Tirr ⩽ 340 °C the boron doped steels show progressive embrittlement with increasing helium amount. Irradiation induced DBTT shift of EUROFER97 based heat doped with 1120 wppm separated 10B isotope could not be quantified due to large embrittlement found in the investigated temperature range. At Tirr ⩽ 340 °C helium induced extra embrittlement is attributed to material hardening induced by helium bubbles and described in terms of phenomenological model.

Focal depth measurement of scanning helium ion microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Hongxuan, E-mail: Guo.hongxuan@nims.go.jp; Itoh, Hiroshi; Wang, Chunmei

2014-07-14

When facing the challenges of critical dimension measurement of complicated nanostructures, such as of the three dimension integrated circuit, characterization of the focal depth of microscopes is important. In this Letter, we developed a method for characterizing the focal depth of a scanning helium ion microscope (HIM) by using an atomic force microscope tip characterizer (ATC). The ATC was tilted in a sample chamber at an angle to the scanning plan. Secondary electron images (SEIs) were obtained at different positions of the ATC. The edge resolution of the SEIs shows the nominal diameters of the helium ion beam at differentmore » focal levels. With this method, the nominal shapes of the helium ion beams were obtained with different apertures. Our results show that a small aperture is necessary to get a high spatial resolution and high depth of field images with HIM. This work provides a method for characterizing and improving the performance of HIM.« less

The thermodynamic properties of normal liquid helium 3

NASA Astrophysics Data System (ADS)

Modarres, M.; Moshfegh, H. R.

2009-09-01

The thermodynamic properties of normal liquid helium 3 are calculated by using the lowest order constrained variational (LOCV) method. The Landau Fermi liquid model and Fermi-Dirac distribution function are considered as our statistical model for the uncorrelated quantum fluid picture and the Lennard-Jones and Aziz potentials are used in our truncated cluster expansion (LOCV) to calculate the correlated energy. The single particle energy is treated variationally through an effective mass. The free energy, pressure, entropy, chemical potential and liquid phase diagram as well as the helium 3 specific heat are evaluated, discussed and compared with the corresponding available experimental data. It is found that the critical temperature for the existence of the pure gas phase is about 4.90 K (4.45 K), which is higher than the experimental prediction of 3.3 K, and the helium 3 flashing temperature is around 0.61 K (0.50 K) for the Lennard-Jones (Aziz) potential.

Cermet coating tribological behavior in high temperature helium

DOE Office of Scientific and Technical Information (OSTI.GOV)

CACHON, Lionel; ALBALADEJO, Serge; TARAUD, Pascal

As the CEA is highly involved in the Generation IV Forum, a comprehensive research and development program has been conducted for several years, in order to establish the feasibility of Gas Cooled Reactor (GCR) technology projects using helium as a cooling fluid. Within this framework, a tribology program was launched in order to select and qualify coatings and materials, and to provide recommendations for the sliding components operating in GCRs. The purpose of this paper is to describe the CEA Helium tribology study on several GCR components (thermal barriers, control rod drive mechanisms, reactor internals, ..) requiring protection against wearmore » and bonding. Tests in helium atmosphere are necessary to be fully representative of tribological environments and to assess the material or coating candidates which can provide a reliable answer to these situations. This paper focuses on the tribology tests performed on CERMET (Cr{sub 3}C-2- NiCr) coatings within a temperature range of between 800 and 1000 deg C.« less

Focal depth measurement of scanning helium ion microscope

NASA Astrophysics Data System (ADS)

Guo, Hongxuan; Itoh, Hiroshi; Wang, Chunmei; Zhang, Han; Fujita, Daisuke

2014-07-01

When facing the challenges of critical dimension measurement of complicated nanostructures, such as of the three dimension integrated circuit, characterization of the focal depth of microscopes is important. In this Letter, we developed a method for characterizing the focal depth of a scanning helium ion microscope (HIM) by using an atomic force microscope tip characterizer (ATC). The ATC was tilted in a sample chamber at an angle to the scanning plan. Secondary electron images (SEIs) were obtained at different positions of the ATC. The edge resolution of the SEIs shows the nominal diameters of the helium ion beam at different focal levels. With this method, the nominal shapes of the helium ion beams were obtained with different apertures. Our results show that a small aperture is necessary to get a high spatial resolution and high depth of field images with HIM. This work provides a method for characterizing and improving the performance of HIM.

Loss Control and Collimation for the LHC

NASA Astrophysics Data System (ADS)

Burkhardt, H.

2005-06-01

The total energy stored in the LHC is expected to reach 360 Mega Joule, which is about two orders of magnitude higher than in HERA or the Tevatron. Damage and quench protection in the LHC require a highly efficient and at the same time very robust collimation system. The currently planned system, the status of the project and the expected performance of the collimation system from injection up to operation with colliding beams will be presented.

Study of helium transfer technology for STICCR: Fluid management

NASA Technical Reports Server (NTRS)

Frank, D. J.; Yuan, S. W. K.; Grove, R. K.; Lheureux, J. M.

1987-01-01

The Space Infrared Telescope Facility (SIRTF) is a long life cryogenically cooled space based telescope for infrared astronomy from 2 to 700 microns currently under study and planned for launch in the mid 90's. SIRTF will operate as a multi-user facility, initially carrying 3 instruments at the focal plane. It will be cooled to below 2 K by superfluid liquid helium to achieve radiometric sensitivity limited only by the statistical fluctuations in the natural infrared background radiation over most of its spectral range. The lifetime of the mission will be limited by the lifetime of the liquid helium supply, and is currently baselined to be 2 years. Candidates are reviewed for a liquid management device to be used in the resupply of liquid helium, and for the selection of an appropriate candidate.

More effective wet turboexpander for the nuclotron helium refrigerators

NASA Astrophysics Data System (ADS)

Agapov, N. N.; Batin, V. I.; Davydov, A. B.; Khodzhibagian, H. G.; Kovalenko, A. D.; Perestoronin, G. A.; Sergeev, I. I.; Stulov, V. L.; Udut, V. N.

2002-05-01

In order to raise the efficiency of cryogenic refrigerators and liquefiers, it is very important to replace the JT process, which involves large losses of exergy, by the improved process of adiabatic expansion. This paper presents test results of the second-generation wet turboexpander for the Nuclotron helium refrigerators. A rotor is fixed vertically by a combination of gas and hydrostatic oil bearings. The turbines are capable to operate at a speed of 300,000 revolutions per minute. The power generated by the turbine goes into friction in the oil bearings. The design of the new wet turboexpander was executed in view of those specific conditions, which arise due to the operation at liquid helium temperature. The application of this new expansion machine increases the efficiency of the Nuclotron helium refrigerators by 25%.

Observations of Lunar Exospheric Helium with LAMP UV Spectrograph onboard the Lunar Reconnaissance Orbiter

NASA Astrophysics Data System (ADS)

Grava, Cesare; Hurley, Dana M.; Retherford, Kurt D.; Gladstone, G. Randall; Feldman, Paul D.; Pryor, Wayne R.; Greathouse, Thomas K.; Mandt, Kathleen E.

2017-04-01

Helium was one of the first elements discovered in the lunar exosphere, being detected by the mass spectrometer LACE (Lunar Atmosphere Composition Experiment) deployed at the lunar surface during the Apollo 17 mission. Most of it comes from neutralization of solar wind alpha particles impinging on the lunar surface, but there is increasing evidence that a non-negligible fraction of it diffuses from the interior of the Moon, as a result of radioactive decay of thorium and uranium. Therefore, pinpointing the amount of endogenic helium can constrain the abundance of these two elements in the crust, with implication for the formation of the Moon. The Lyman-Alpha Mapping Project (LAMP) far-UV spectrograph onboard the Lunar Reconnaissance Orbiter (LRO) carried out an atmospheric campaign to study the lunar exospheric helium. The spacecraft was pitched along the direction of motion to look through a longer illuminated column of gas, compared to the usual nadir-looking mode, and therefore enhancing the brightness of the emission line at 58.4 nm of helium atoms resonantly scattering solar photons. The lines of sight of the observations spanned a variety of local times, latitudes, longitudes, and altitudes, allowing us to reconstruct the temporal and spatial distribution of helium and its radial density profile with the help of an exospheric model. Moreover, correlating the helium density inferred by LAMP with the flux of solar wind alpha particles (the main source of lunar helium) measured from the twin ARTEMIS spacecraft, it is possible to constrain the amount of helium which comes from the interior of the Moon via outgassing. While most of the observations can be explained by the exospheric model, we have found discrepancies between the model and LAMP observations, with the former underestimating the latter, especially at northern selenographic latitudes, when LRO altitude is maximum. Such discrepancies suggest that the vertical distribution of helium differs from a

The surprisingly transparent sQGP at LHC

NASA Astrophysics Data System (ADS)

Horowitz, W. A.; Gyulassy, Miklos

2011-12-01

We present parameter-free predictions of the nuclear modification factor, RAAπ(p,s), of high p pions produced in Pb + Pb collisions at s=2.76 and 5.5 ATeV based on the WHDG/DGLV (radiative + elastic + geometric fluctuation) jet energy loss model. The initial quark gluon plasma (QGP) density at LHC is constrained from a rigorous statistical analysis of PHENIX/RHIC π quenching data at s=0.2 ATeV and the charged particle multiplicity at ALICE/LHC at 2.76 ATeV. Our perturbative QCD tomographic theory predicts significant differences between jet quenching at RHIC and LHC energies, which are qualitatively consistent with the p-dependence and normalization—within the large systematic uncertainty—of the first charged hadron nuclear modification factor, RAAch, data measured by ALICE. However, our constrained prediction of the central to peripheral pion modification, Rcpπ(p), for which large systematic uncertainties associated with unmeasured p + p reference data cancel, is found to be over-quenched relative to the charged hadron ALICE Rcpch data in the range 5LHC identified (h=π,K,p) hadron RAAh data (together with precise p + p, p + Pb, and Z boson and direct photon Pb + Pb control data) are needed to assess if the QGP produced at LHC is indeed less opaque to jets than predicted by constrained extrapolations from RHIC.

Molecular dynamics study of the role of symmetric tilt grain boundaries on the helium distribution in nickel

NASA Astrophysics Data System (ADS)

Torres, E.; Pencer, J.

2018-04-01

Helium impurities, from either direct implantation or transmutation reactions, have been associated with embrittlement in nickel-based alloys. Helium has very low solubility in nickel, and has been found to aggregate at lattice defects such as vacancies, dislocations, and grain boundaries. The retention and precipitation of helium in nickel-based alloys have deleterious effects on the material mechanical properties. However, the underlying mechanisms that lead to helium effects in the host metal are not fully understood. In the present work, we investigate the role of symmetric tilt grain boundary (STGB) structures on the distribution of helium in nickel using molecular dynamics simulations. We investigate the family of STGBs specific to the 〈 110 〉 tilt axis. The present results indicate that accumulation of helium at the grain boundary may be modulated by details of grain boundary geometry. A plausible correlation between the grain boundary energy and misorientation with the accumulation and mobility of helium is proposed. Small clusters with up to 6 helium atoms show significant interstitial mobility in the nickel bulk, but also become sites for nucleation and grow of more stable helium clusters. High-energy GBs are found mainly populated with small helium clusters. The high mobility of small clusters along the GBs indicates the role of these GBs as fast two-dimensional channels for diffusion. In contrast, the accumulation of helium in large helium clusters at low-energy STGB creates a favorable environment for the formation of large helium bubbles, indicating a potential role for low-energy STGB in promoting helium-induced GB embrittlement.

Persistent Currents in a Rotating Superleak Partially Filled with Superfluid Helium.

DTIC Science & Technology

1982-12-01

the difference in pressure of the helium bath Po and the reduced vapor pressure in the cell P. In the region from 1.0 to 0.1 the log Po-P has been seen...easily measurable quantities of temperature, T, the helium bath pressure, Po, and the cell pressure P to the film thickness d. Alpha is a measure of the...rotation is controlled by a motor and power supply. The temperature is controlled by the pumping rate and a feedback heater in the helium bath and -maybe

The Hottest Horizontal-Branch Stars in Omega Centauri: Late Hot Flasher vs. Helium Enrichment

NASA Technical Reports Server (NTRS)

Moehler, S.; Dreizler, S.; Lanz, T.; Bono, G.; Sweigart, A V.; Calamida, A.; Monelli, M.; Nonino, M.

2007-01-01

UV observations of some massive globular clusters uncovered a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario here stars experience the helium flash while on the white dwarf cooling curve or by the helium-rich sub-population recently postulated to exist in some clusters. Spectroscopic analyses of blue hook stars in omega Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C, N enrichment could not be verified from existing data. We want to determine effective temperatures, surface gravities and abundances of He, C, N in blue hook and canonical extreme horizontal branch (EHB) star candidates. Moderately high resolution spectra of stars at the hot end of the blue horizontal branch in the globular cluster omega Cen were analysed for atmospheric parameters (T(sub eff), log g) and abundances using LTE and Non-LTE model atmospheres. In the temperature range 30,000 K to 50,000 K we find that 37% of our stars are helium-poor (log nHe/nH less than -2), 49% have solar helium abundance within a factor of 3 (-1.5 less than or equal to log nHe/nH less than or equal to -0.5) and 14% are helium rich (log nHe/nH greater than -0.4). We also find carbon enrichment in step with helium enrichment, with a maximum carbon enrichment of 3% by mass. At least 30% of the hottest HB stars in omega Centauri show helium abundances well above the predictions from the helium enrichment scenario (Y = 0.42 corresponding to log nHe/nH approximately equal to -0.74). In addition the most helium-rich stars show strong carbon enrichment as predicted by the late hot flasher scenario. We conclude that the helium-rich HB stars in omega Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence.

Relief diffracted elements recorded on absorbent photopolymers.

PubMed

Gallego, S; Márquez, A; Ortuño, M; Francés, J; Pascual, I; Beléndez, A

2012-05-07

Relief surface changes provide interesting possibilities for storing diffractive optical elements on photopolymers and are an important source of information for characterizing and understanding the material behavior. In this paper we use a 3-dimensional model, based on direct parameter measurements, for predicting the relief structures generated on without-coverplate photopolymers. We have analyzed different spatial frequency and recording intensity distributions such as binary and blazed periodic patterns. This model was successfully applied to different photopolymers with different values of monomer diffusion.

Helium transfer from water into quartz crystals: A new approach for porewater dating [rapid communication

NASA Astrophysics Data System (ADS)

Tolstikhin, I.; Gannibal, M.; Tarakanov, S.; Pevzner, B.; Lehmann, B.; Ihly, B.; Waber, H. N.

2005-09-01

Several important fundamental and applied problems require a quantification of slow rates of groundwater flow. To resolve these problems helium appears to be a promising tracer. In this contribution we discuss a new approach, which gives the helium inventory in a rock - pore water system by using the relevant mineral record, i.e., without extraction and investigation of the porewater samples. Some U- and Th-poor minerals such as quartz (quartz separates from Permo-Carboniferous Formation, sandstone-shale interlayering, Molasses Basin, Northern Switzerland, hereafter PCF, are used in this study) contain excessive helium having migrated into their internal helium-accessible volume (HAV) from the surrounding porewater [I.N. Tolstikhin, B.E. Lehmann, H.H. Loosli, A. Gautschi, Helium and argon isotopes in rocks, minerals and related groundwaters: a case study in Northern Switzerland, Geochim. Cosmochim. Acta 60 (1996) 1497-1514]. These volumes are estimated by using helium as a nano-size penetrating tool, i.e., by saturation of the minerals with helium under controlled pressure-temperature conditions and subsequent measurements of the helium-saturated concentrations. In the quartz separates HAV/total volume ratios vary from 0.017% to 0.16%; along with the measured initial (unsaturated) He concentration the HAV gives the internal helium pressure, the mean value obtained for 7 samples (25 sample aliquots) is P = 0.45 ± 0.15 atm (1 σ). The product of helium pressure and solubility (7.35 × 10 - 3 cc STP He/cc H 2O for the temperature and salinity of PCF aquifers reported in [F.J. Pearson, W. Balderer, H.H. Loosli, B.E. Lehmann, A. Matter, T. Peters, H. Schmassmann, A. Gautschi, Applied Isotope Hydrogeology-A Case Study in Northern Switzerland, Elsevier Amsterdam, 1991, 439 pp.]) is the mineral-derived He concentration in the respective porewater, CPW = 0.0035 ± 0.0017 cc He/cc H 2O. This value is in full accord with measured He concentrations in PCF aquifers, CPCF

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 1 2014-10-01 2014-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

26 CFR 1.6015-5 - Time and manner for requesting relief.

Code of Federal Regulations, 2010 CFR

2010-04-01

... relief. (a) Requesting relief. To elect the application of § 1.6015-2 or 1.6015-3, or to request... general. To elect the application of § 1.6015-2 or 1.6015-3, or to request equitable relief under § 1.6015... spouse after July 22, 1998, with respect to the joint tax liability. (2) Definitions—(i) Collection...

Impact of a CP-violating Higgs sector: from LHC to baryogenesis.

PubMed

Shu, Jing; Zhang, Yue

2013-08-30

We observe a generic connection between LHC Higgs data and electroweak baryogenesis: the particle that contributes to the CP-odd hgg or hγγ vertex would provide the CP-violating source during a first-order phase transition. It is illustrated in the two Higgs doublet model that a common complex phase controls the lightest Higgs properties at the LHC, electric dipole moments, and the CP-violating source for electroweak baryogenesis. We perform a general parametrization of Higgs effective couplings and a global fit to the LHC Higgs data. Current LHC measurements prefer a nonzero phase for tanβ≲1 and electric dipole moment constraints still allow an order-one phase for tanβ∼1, which gives sufficient room to generate the correct cosmic baryon asymmetry. We also give some prospects in the direct measurements of CP violation in the Higgs sector at the LHC.

Diffusion of Hydrogen and Helium in Inconel 625

NASA Technical Reports Server (NTRS)

Palosz, W.; Gillies, D.; Lehoczky, S.

2006-01-01

Diffusion parameters for hydrogen and helium in Inconel 625 were investigated. The dependence of permeability of hydrogen in the temperature range 310 - 750 C is given. Solubility of hydrogen at 1 atm in the range 640 - 860 C was determined and diffusivity of the gas was calculated. Experiments with diffusion and solubility at 0.09 atm suggest a molecular mechanism of solution of hydrogen in the material. Diffusivity of helium was estimated at less than 10(exp -18) sq cm/s (at 1040 C).

Coordination and resource maximization during disaster relief efforts.

PubMed

Lee, Vernon J; Low, Edwin

2006-01-01

In the aftermath of the Earthquake and Tsunami in Southeast Asia, many relief organizations sent medical aid to affected areas. The aim of this paper is to examine the mix of healthcare workers resulting from an influx of aid to Meulaboh, Indonesia, and how they met local healthcare needs. Data were collected from the registration center for relief organizations in Meulaboh and daily hospital meetings on healthcare needs and available workers. Prior to the Tsunami, there were 14 doctors and 120 nurses in the hospital. By the third week after the Tsunami, there were 21 surgeons performing 10 surgeries daily, and >20 non-surgical doctors in the 90-bed hospital. There were <70 nurses available during the month after the Tsunami, which was insufficient for the needs of the hospital. In the town of Meulaboh, the number of doctors exceeded the number of nurses, while public health workers comprised <5% of the healthcare workers. An initial disaster-coordinating agency, formed by the United Nations (UN) in conjunction with affected countries, should link actively with relief organizations. This will optimize help in meeting local needs, and direct relief to where it is needed most.

Recovery of purified helium or hydrogen from gas mixtures

DOEpatents

Merriman, J.R.; Pashley, J.H.; Stephenson, M.J.; Dunthorn, D.I.

1974-01-15

A process is described for the removal of helium or hydrogen from gaseous mixtures also containing contaminants. The gaseous mixture is contacted with a liquid fluorocarbon in an absorption zone maintained at superatomspheric pressure to preferentially absorb the contaminants in the fluorocarbon. Unabsorbed gas enriched in hydrogen or helium is withdrawn from the absorption zone as product. Liquid fluorocarbon enriched in contaminants is withdrawn separately from the absorption zone. (10 claims)

Torsion limits from t t macr production at the LHC

NASA Astrophysics Data System (ADS)

de Almeida, F. M. L.; de Andrade, F. R.; do Vale, M. A. B.; Nepomuceno, A. A.

2018-04-01

Torsion models constitute a well-known class of extended quantum gravity models. In this work, one investigates the phenomenological consequences of a torsion field interacting with top quarks at the LHC. A torsion field could appear as a new heavy state characterized by its mass and couplings to fermions. This new state would form a resonance decaying into a top antitop pair. The latest ATLAS t t ¯ production results from LHC 13 TeV data are used to set limits on torsion parameters. The integrated luminosity needed to observe torsion resonance at the next LHC upgrades are also evaluated, considering different values for the torsion mass and its couplings to Standard Model fermions. Finally, prospects for torsion exclusion at the future LHC phases II and III are obtained using fast detector simulations.

Lead ions and Coulomb’s Law at the LHC (CERN)

NASA Astrophysics Data System (ADS)

Cid-Vidal, Xabier; Cid, Ramon

2018-03-01

Although for most of the time the Large Hadron Collider (LHC) at CERN collides protons, for around one month every year lead ions are collided, to expand the diversity of the LHC research programme. Furthermore, in an effort not originally foreseen, proton-lead collisions are also taking place, with results of high interest to the physics community. All the large experiments of the LHC have now joined the heavy-ion programme, including the LHCb experiment, which was not at first expected to be part of it. The aim of this article is to introduce a few simple physical calculations relating to some electrical phenomena that occur when lead-ion bunches are running in the LHC, using Coulomb’s Law, to be taken to the secondary school classroom to help students understand some important physical concepts.

ERDA, RBS, TEM and SEM characterization of microstructural evolution in helium-implanted Hastelloy N alloy

NASA Astrophysics Data System (ADS)

Gao, Jie; Bao, Liangman; Huang, Hefei; Li, Yan; Lei, Qiantao; Deng, Qi; Liu, Zhe; Yang, Guo; Shi, Liqun

2017-05-01

Hastelloy N alloy was implanted with 30 keV, 5 × 1016 ions/cm2 helium ions at room temperature, and subsequent annealed at 600 °C for 1 h and further annealed at 850 °C for 5 h in vacuum. Using elastic recoil detection analysis (ERDA) and transmission electron microscopy (TEM), the depth profiles of helium concentration and helium bubbles in helium-implanted Hastelloy N alloy were investigated, respectively. The diffusion of helium and molybdenum elements to surface occurred during the vacuum annealing at 850 °C (5 h). It was also observed that bubbles in molybdenum-enriched region were much larger in size than those in deeper region. In addition, it is worth noting that plenty of nano-holes can be observed on the surface of helium-implanted sample after high temperature annealing by scanning electron microscope (SEM). This observation provides the evidence for the occurrence of helium release, which can be also inferred from the results of ERDA and TEM analysis.

Pulsed beam of extremely large helium droplets

NASA Astrophysics Data System (ADS)

Kuma, Susumu; Azuma, Toshiyuki

2017-12-01

We generated a pulsed helium droplet beam with average droplet diameters of up to 2 μ m using a solenoid pulsed valve operated at temperatures as low as 7 K. The droplet diameter was controllable over two orders of magnitude, or six orders of the number of atoms per droplet, by lowering the valve temperature from 21 to 7 K. A sudden droplet size change attributed to the so-called ;supercritical expansion; was firstly observed in pulsed mode, which is necessary to obtain the micrometer-scale droplets. This beam source is beneficial for experiments that require extremely large helium droplets in intense, pulsed form.

Effects of displacement damage and helium production rates on the nucleation and growth of helium bubbles - Positron annihilation spectroscopy aspects

NASA Astrophysics Data System (ADS)

Krsjak, Vladimir; Degmova, Jarmila; Sojak, Stanislav; Slugen, Vladimir

2018-02-01

Fe-12 wt% Cr model alloy samples were implanted by 250 keV He2+ ions to three different fluencies (3 × 1017, 9 × 1017 and 1.5 × 1018 cm-2) at T < 100 °C. In a depth profile manner, the implantation impact according to defined peak profile was investigated using variable energy slow positrons, with the primary focus on the 2-13 dpa region. The obtained data were compared to published data on Optifer IX steel samples [1] irradiated in the frame of a two-years irradiation program of the Swiss Spallation Neutron Source. Bi-modal defect distribution represented by two defect components in positron lifetime spectrum reveals two distinct helium bubbles growth mechanisms. While at the lower helium production rate of the spallation environment, the bubbles grow primarily by migration and coalescence, at the high production rates of helium in the implanted samples, the results indicate this growth is driven by Ostwald ripening mechanism. A competitive growth process via emission of interstitial atoms (clusters) is discussed in terms of low-temperature He implantations.

7 CFR 795.24 - Relief.

Code of Federal Regulations, 2011 CFR

2011-01-01

... PROVISIONS COMMON TO MORE THAN ONE PROGRAM PAYMENT LIMITATION General § 795.24 Relief. If a producer relied... determined that the producers acted in good faith based upon the original “person” determination. [51 FR 8454...

7 CFR 795.24 - Relief.

Code of Federal Regulations, 2010 CFR

2010-01-01

... PROVISIONS COMMON TO MORE THAN ONE PROGRAM PAYMENT LIMITATION General § 795.24 Relief. If a producer relied... determined that the producers acted in good faith based upon the original “person” determination. [51 FR 8454...

Liquid helium-free cryostat and hermetically sealed cryogenic microwave cavity for hyperfine spectroscopy of antiprotonic helium

PubMed Central

Massiczek, O.; Friedreich, S.; Juhász, B.; Widmann, E.; Zmeskal, J.

2011-01-01

The design and properties of a new cryogenic set-up for laser–microwave–laser hyperfine structure spectroscopy of antiprotonic helium – an experiment performed at the CERN-Antiproton Decelerator (AD), Geneva, Switzerland – are described. Similar experiments for 4He have been performed at the AD for several years. Due to the usage of a liquid helium operated cryostat and therefore necessary refilling of coolants, a loss of up to 10% beamtime occurred. The decision was made to change the cooling system to a closed-circuit cryocooler. New hermetically sealed target cells with minimised 3He gas volume and different dimensions of the microwave resonator for measuring the 3He transitions were needed. A new set-up has been designed and tested at Stefan Meyer Institute in Vienna before being used for the 2009 and 2010 beamtimes at the AD. PMID:22267883

Integration of real-time mapping technology in disaster relief distribution.

DOT National Transportation Integrated Search

2013-02-01

Vehicle routing for disaster relief distribution involves many challenges that distinguish this problem from those in commercial settings, given the time sensitive and resource constrained nature of relief activities. While operations research approa...

Crystal orientation effects on helium ion depth distributions and adatom formation processes in plasma-facing tungsten

DOE PAGES

Hammond, Karl D.; Wirth, Brian D.

2014-10-09

Here, we present atomistic simulations that show the effect of surface orientation on helium depth distributions and surface feature formation as a result of low-energy helium plasma exposure. We find a pronounced effect of surface orientation on the initial depth of implanted helium ions, as well as a difference in reflection and helium retention across different surface orientations. Our results indicate that single helium interstitials are sufficient to induce the formation of adatom/substitutional helium pairs under certain highly corrugated tungsten surfaces, such as {1 1 1}-orientations, leading to the formation of a relatively concentrated layer of immobile helium immediately belowmore » the surface. The energies involved for helium-induced adatom formation on {1 1 1} and {2 1 1} surfaces are exoergic for even a single adatom very close to the surface, while {0 0 1} and {0 1 1} surfaces require two or even three helium atoms in a cluster before a substitutional helium cluster and adatom will form with reasonable probability. This phenomenon results in much higher initial helium retention during helium plasma exposure to {1 1 1} and {2 1 1} tungsten surfaces than is observed for {0 0 1} or {0 1 1} surfaces and is much higher than can be attributed to differences in the initial depth distributions alone. Lastly, the layer thus formed may serve as nucleation sites for further bubble formation and growth or as a source of material embrittlement or fatigue, which may have implications for the formation of tungsten “fuzz” in plasma-facing divertors for magnetic-confinement nuclear fusion reactors and/or the lifetime of such divertors.« less

Helium dilution refrigeration system

DOEpatents

Roach, Patrick R.; Gray, Kenneth E.

1988-01-01

A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

Helium dilution refrigeration system

DOEpatents

Roach, P.R.; Gray, K.E.

1988-09-13

A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation is disclosed. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains [sup 3]He and [sup 4]He liquids which are precooled by a coupled container containing [sup 3]He liquid, enabling the phase separation of a [sup 3]He rich liquid phase from a dilute [sup 3]He-[sup 4]He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the [sup 3]He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute [sup 3]He-[sup 4]He liquid phase. 2 figs.

Ice thickness and topographic relief in glaciated landscapes of the western USA

NASA Astrophysics Data System (ADS)

Brocklehurst, Simon H.; Whipple, Kelin X.; Foster, David

2008-05-01

The development of relief in glaciated landscapes plays a crucial role in hypotheses relating climate change and tectonic processes. In particular, glaciers can only be responsible for peak uplift if they are capable of generating significant relief in formerly nonglaciated landscapes. Previous work has suggested that relief in glaciated landscapes should scale with the thickness of the ice. Here we summarise a field-based test of this hypothesis in two mountain ranges in the western United States, the Sierra Nevada, California, and the Sangre de Cristo Range, Colorado. These areas exhibit a range of degrees of glacial occupation during the Quaternary, including some drainage basins essentially unoccupied by ice, allowing a detailed exploration of how relief in different parts of a drainage basin evolves in response to glacial modification. We mapped last glacial maximum (LGM) trimlines to estimate the ice thickness at the equilibrium line altitude during the LGM, and determined several metrics of relief for drainage basins across the full spectrum of LGM ice extents. Comparison between measures of relief and ice thickness estimates indicates that relief production in glaciated mountain belts scales with ice thickness and consequently also drainage area. We extended our study to the Bitterroot Range in Idaho/Montana, and the Teton Range in Wyoming, for a more comprehensive understanding of sub-ridgeline relief, or 'missing mass'. This measure of mean relief is surprisingly little affected by either the degree of glacial modification or the total material removed by glaciers, but appears to be influenced by the more active tectonics of the Teton Range. While the effects of glacial modification on the landscape are clear (valley widening, hanging valley formation), the overall change in the relief structure of the mountain ranges studied here is surprisingly modest.

Development Specification for RV-346/348 Positive Pressure Relief Valves (PPRV)

NASA Technical Reports Server (NTRS)

Ralston, Russell L.

2017-01-01

This specification establishes the requirements for design, performance, safety, testing, and manufacture of the RV-346 and RV-348, Positive Pressure Relief Valve (PPRV) as part of the Advanced Extravehicular Mobility Unit (EMU)(AEMU) Portable Life Support System (PLSS). The RV-346 serves as the Positive Pressure Relief Valve (PPRV), and the RV-348 serves as the Secondary Positive Pressure Relief Valve (SPPRV).

32 CFR 2.2 - Statutory relief for participating programs.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 1 2012-07-01 2012-07-01 false Statutory relief for participating programs. 2.2 Section 2.2 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE ACQUISITION PILOT PROGRAM POLICY § 2.2 Statutory relief for participating programs. (a) Within the limitations prescribed...

32 CFR 2.2 - Statutory relief for participating programs.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 1 2010-07-01 2010-07-01 false Statutory relief for participating programs. 2.2 Section 2.2 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE ACQUISITION PILOT PROGRAM POLICY § 2.2 Statutory relief for participating programs. (a) Within the limitations prescribed...

32 CFR 2.2 - Statutory relief for participating programs.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 1 2011-07-01 2011-07-01 false Statutory relief for participating programs. 2.2 Section 2.2 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE ACQUISITION PILOT PROGRAM POLICY § 2.2 Statutory relief for participating programs. (a) Within the limitations prescribed...

32 CFR 2.2 - Statutory relief for participating programs.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 1 2014-07-01 2014-07-01 false Statutory relief for participating programs. 2.2 Section 2.2 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE ACQUISITION PILOT PROGRAM POLICY § 2.2 Statutory relief for participating programs. (a) Within the limitations prescribed...

32 CFR 2.2 - Statutory relief for participating programs.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 1 2013-07-01 2013-07-01 false Statutory relief for participating programs. 2.2 Section 2.2 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE ACQUISITION PILOT PROGRAM POLICY § 2.2 Statutory relief for participating programs. (a) Within the limitations prescribed...

30 CFR 203.53 - What relief will MMS grant?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 2 2011-07-01 2011-07-01 false What relief will MMS grant? 203.53 Section 203.53 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR MINERALS REVENUE MANAGEMENT RELIEF OR REDUCTION IN ROYALTY RATES OCS Oil, Gas, and Sulfur...

31 CFR 306.111 - Procedure for applying for relief.

Code of Federal Regulations, 2010 CFR